HYDRAULIC CONTROL SYSTEM AND HYDRAULIC CONTROL METHOD FOR GRADER, AND GRADER

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of International Application No. PCT/CN2024/073887, filed on Jan. 24, 2024, which claims priority to Chinese Patent Application No. 202311404299.2, filed on Oct. 26, 2023. All of the aforementioned applications are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present application relates to the field of grader technologies, and in particular, to a hydraulic control system for a grader, a hydraulic control method for a grader, and a grader.

BACKGROUND

At present, a grader, as a type of earth-moving machinery, a working device thereof may be applied to various working conditions such as earthwork leveling, ditch excavation, and slope trimming by changing a lock pin hole position. In the related art, inserting and removing manners of a lock pin of a grader swing frame mainly include a manual inserting and removing manner and a hydraulic control inserting and removing manner. The hydraulic control inserting and removing manner is widely used due to its convenience.

However, during the hydraulic control inserting and removing process, left and right lift cylinders and a swinging cylinder are in a locked state, resulting in that an unbalanced pressure of each hydraulic cylinder exerts a significant radial load on the lock pin. Moreover, as the working device and bearings of a swing frame mechanism wear out, the radial load will further increase, thereby making it difficult to unplug the lock pin, and thus affecting construction efficiency.

SUMMARY

Embodiments of the present application aim to solve at least one of technical problems existing in the conventional technologies.

In the first aspect, according to the embodiments of the present application, the hydraulic control system for the grader is provided. The hydraulic control system for the grader is applied to the grader. The grader includes a swing frame assembly and a first working device, and the swing frame assembly is provided with a plurality of lock pin holes. The hydraulic control system for the grader includes a cylinder assembly, a lock pin assembly and a control valve group. The cylinder assembly is connected to the swing frame assembly and the first working device, and the cylinder assembly includes a plurality of first working cylinders. The lock pin assembly includes a driving member and a lock pin connected to each other. The lock pin is configured to be inserted into or removed from any one of the plurality of lock pin holes when driven by the driving member. The control valve group is connected to at least one of the plurality of first working cylinders. In a case that the control valve group causes an oil pressure in an oil chamber of the at least one of the first working cylinders to be less than or equal to a preset value, the driving member drives the lock pin to be removed from the lock pin hole.

According to the hydraulic control system for the grader provided by the embodiments of the present application, before removing the lock pin, the oil pressure in the oil chamber of the at least one of the first working cylinders is reduced to make the at least one of the first working cylinders be in a floating state, that is, pressure in the at least one of the first working cylinders is released, thereby reducing a radial force applied to the lock pin, and thus achieving unloading of a radial load on the lock pin. In this case, the lock pin is driven to be removed from the lock pin hole by the driving member, so that the difficulty of removing the lock pin may be reduced, thereby achieving rapid removal of the lock pin, and thus improving construction efficiency.

According to the second aspect of the present application, the grader is provided. The grader includes the hydraulic control system for the grader provided by any one of the above technical solutions. Therefore, it has all the beneficial technical effects of the hydraulic control system for the grader, which will not be repeated herein. Further, the grader also includes a display screen, the display screen is electrically connected to the control valve group.

According to the third aspect of the present application, the hydraulic control method for the grader is provided. The grader includes a swing frame assembly, a first working device, a cylinder assembly and a lock pin assembly. The cylinder assembly is connected to the swing frame assembly and the first working device, and the cylinder assembly includes a plurality of first working cylinders. The swing frame assembly is provided with a plurality of lock pin holes, and the lock pin assembly includes a driving member and a lock pin connected to each other. The lock pin is configured to be inserted into or removed from any one of the plurality of lock pin holes when driven by the driving member, and the hydraulic control method includes: performing pressure relief on an oil chamber of at least one of the first working cylinders to make an oil pressure in the oil chamber of the at least one of the first working cylinders be less than or equal to a preset value; and controlling the driving member to drive the lock pin to be removed from the lock pin hole.

According to the hydraulic control method for the grader provided by the embodiments of the present application, before removing the lock pin, the pressure in the at least one of the first working cylinders is released to make the at least one of the first working cylinders be in a floating state, thereby reducing a radial force applied to the lock pin, and thus achieving unloading of a radial load on the lock pin. In this case, the lock pin is driven to be removed from the lock pin hole by the driving member, so that the difficulty of removing the lock pin may be reduced, thereby achieving rapid removal of the lock pin, and thus improving construction efficiency.

Additional aspects and advantages of the present application will be given in the following description, a portion of which will become apparent from the following description, or be understood through practice of the present application.

BRIEF DESCRIPTION OF THE DRAWINGS

The aforementioned and/or additional aspects and advantages of the present application will become apparent and easily understood from description of the embodiments with reference to following drawings.

FIG. 1 is a schematic structural diagram of a hydraulic control system for a grader provided by an embodiment of the present application.

FIG. 2 is a schematic structural diagram of a display screen provided by an embodiment of the present application.

FIG. 3 is another schematic structural diagram of a hydraulic control system for a grader provided by an embodiment of the present application.

FIG. 4 is another schematic structural diagram of a display screen provided by an embodiment of the present application.

FIG. 5 is yet another schematic structural diagram of a hydraulic control system for a grader provided by an embodiment of the present application.

FIG. 6 is yet another schematic structural diagram of a display screen provided by an embodiment of the present application.

FIG. 7 is a schematic structural diagram of a grader provided by an embodiment of the present application.

FIG. 8 is another schematic structural diagram of a grader provided by an embodiment of the present application.

FIG. 9 is a schematic flowchart of a hydraulic control method for a grader provided by an embodiment of the present application.

FIG. 10 is another schematic flowchart of a hydraulic control method for a grader provided by an embodiment of the present application.

FIG. 11 is yet another schematic flowchart of a hydraulic control method for a grader provided by an embodiment of the present application.

FIG. 12 is still another schematic flowchart of a hydraulic control method for a grader provided by an embodiment of the present application.

DETAILED DESCRIPTION OF THE EMBODIMENTS

To more clearly illustrate the above objectives, features, and advantages of the present application, the present application will be described in further detail with reference to drawings and specific implements. It should be noted that, in a case of no conflict, the embodiments of the present application and the features in the embodiments may be combined with each other.

In following description, many specific details are described to facilitate thoroughly understanding the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present application is not limited by the specific embodiments disclosed below.

With reference to FIG. 1 to FIG. 12, a hydraulic control system for a grader 100, a grader 300, and a hydraulic control method for a grader provided by some embodiments of the present application will be described below.

According to an embodiment of the present application, as shown in FIG. 1, FIG. 2, FIG. 3, FIG. 7, and FIG. 8, the hydraulic control system for the grader 100 is proposed. The hydraulic control system for the grader 100 is applied to the grader 300. The grader 300 includes a swing frame assembly 320 and a first working device 330, and the swing frame assembly 320 is provided with a plurality of lock pin holes 321. The hydraulic control system for the grader 100 includes a cylinder assembly 110, a lock pin assembly 120 and a control valve group 130. The cylinder assembly 110 is connected to the swing frame assembly 320 and the first working device 330, and the cylinder assembly 110 includes a plurality of first working cylinders 111. The lock pin assembly 120 includes a driving member 121 and a lock pin 122 connected to each other, and the lock pin 122 is configured to be inserted into or removed from any one of the plurality of lock pin holes 321 when driven by the driving member 121. The control valve group 130 is connected to at least one of the plurality of first working cylinders 111. In a case that the control valve group 130 causes an oil pressure in an oil chamber of the at least one of the first working cylinders 111 to be less than or equal to a preset value, the driving member 121 drives the lock pin 122 to be removed from the lock pin hole 321.

The hydraulic control system for the grader 100 provided by the embodiments of the present application includes the cylinder assembly 110, the lock pin assembly 120 and the control valve group 130. Specifically, the grader 300 includes the swing frame assembly 320 and the first working device 330, and the cylinder assembly 110 is connected to the swing frame assembly 320 and the first working device 330. Optionally, the first working device 330 includes a blade.

The swing frame assembly 320 is provided with the plurality of lock pin holes 321. The lock pin assembly 120 includes the lock pin 122 and the driving member 121 connected to each other. When driven by the driving member 121, the lock pin 122 is capable of being inserted into or removed from any one of the lock pin holes 321 to make the first working device 330 switch between different working postures by changing the lock pin hole 321, and thus allowing it to operate under various conditions such as earthwork leveling, ditch excavation, and slope trimming.

When it is necessary to remove the lock pin 122 from the lock pin hole 321 to change the lock pin hole 321, due to imbalance in pressures among the plurality of first working cylinders 111 in the cylinder assembly 110, a significant radial load is applied to the lock pin 122. Moreover, as a usage time of the apparatus increases, or the first working device 330 and bearings of the swing frame assembly 320 wear out, or factors like this, resulting the pressure imbalance among various hydraulic cylinders under working conditions intensifies, thereby making it difficult to remove the lock pin 122, and thus affecting the construction efficiency.

The cylinder assembly 110 includes the plurality of first working cylinders 111. Optionally, the plurality of first working cylinders 111 include lift cylinders 113 and a swing cylinder. The lift cylinders 113 includes a left lift cylinder and a right lift cylinder.

The control valve group 130 is connected to at least one of the first working cylinders 111, and the control valve group 130 is capable of releasing the pressure of the oil chamber of the at least one of the first working cylinders 111 to reduce the oil pressure in the oil chamber of the at least one of the first working cylinders 111. When the oil pressure in the oil chamber of the at least one of the first working cylinders 111 decreases below the preset value, the lock pin 122 is driven by the driving member 121 to be removed from the lock pin hole 321.

In other words, before removing the lock pin 122, the oil pressure in the oil chamber of the at least one of the first working cylinders 111 is reduced to make the at least one of the first working cylinders 111 be in a floating state. That is, the pressure of the at least one of the first working cylinders 111 is released, thereby reducing a radial force applied to the lock pin 122, and thus achieving unloading of the radial load on the lock pin 122. In this case, when the lock pin 122 is driven by the driving member 121 to be removed from the lock pin hole 321, the difficulty of removing the lock pin 122 is reduced, thereby achieving the rapid removal of the lock pin 122, and thus improving the construction efficiency.

Optionally, when the oil pressure in the oil chamber of the at least one of the first working cylinders 111 is less than or equal to the preset value, the oil pressure in the oil chamber of the at least one of the first working cylinders 111 is a standby oil pressure of a system, or the oil pressure in the oil chamber of the at least one of the first working cylinders 111 is equal to 0 MPa.

The oil in at least one of the first working cylinders 111 is released to an oil return port 152 of an oil source 150. When the oil pressure in the oil chamber of the at least one of the first working cylinders 111 is less than or equal to the preset value, the oil pressure in the oil chamber of the at least one of the first working cylinders 111 is the standby oil pressure of the system.

When the oil in the at least one of the first working cylinders 111 is released to another oil tank, the oil pressure in the oil chamber of the at least one of the first working cylinder 111 may be 0 MPa when the oil pressure in the oil chamber of the at least one of the first working cylinders 111 is less than or equal to the preset value, that is, the pressure in the at least one of the first working cylinders 111 is eliminated, thereby further reducing the radial force applied to the lock pin 122, and thus achieving complete unloading of the radial load on the lock pin 122.

In other words, the control valve group 130 may be used for communicating with the oil chamber of the at least one of the first working cylinders 111 and the oil return port 152 of the oil source 150 or another oil tank to release the pressure in the oil chamber of the at least one of the first working cylinders 111.

Optionally, the preset value is 1 MPa or 2 MPa. When the oil pressure in the oil chamber of the at least one of the first working cylinders 111 is depressurized to the standby oil pressure of the system, the standby oil pressure is less than or equal to 1 MPa, or the standby oil pressure is less than or equal to 2 MPa.

Alternatively, the lock pin 122 is removed when the oil pressure in the oil chamber of the at least one of the first working cylinders 111 is depressurized below 1 MPa or 2 MPa.

Optionally, the left lift cylinder and the right lift cylinder may be simultaneously placed in a floating state. Alternatively, the left lift cylinder and the swing cylinder may be simultaneously placed in the floating state, or the right lift cylinder and the swing cylinder may be simultaneously placed in the floating state, or the left lift cylinder, the right lift cylinder, and the swing cylinder may be simultaneously placed in the floating state, so that the radial load applied to the lock pin 122 due to the pressure imbalance of the cylinders is minimized, thereby further achieving the rapid removal of the lock pin 122.

In some embodiments, the control valve group 130 is capable of making the oil pressure in the oil chamber of the at least one of the first working cylinders 111 be equal to 0 MPa.

In this embodiment, an unbalanced force of the at least one of the first working cylinders 111 is eliminated, so that the radial force applied to the lock pin 122 is further reduced, thereby achieving the complete unloading of the radial load on the lock pin 122, and thus the difficulty of removing the lock pin 122 is further reduced.

Optionally, when the oil in the at least one of the first working cylinders 111 is released to another oil tank, the oil pressure in the oil chamber of the at least one of the first working cylinders 111 may be depressurized to 0 MPa.

When the left lift cylinder, the right lift cylinder, and the swing cylinder are simultaneously placed in the floating state, the first working device 330 rests on the ground in a floating condition.

As shown in FIG. 1, FIG. 2, and FIG. 3, in some embodiments, the hydraulic control system 100 for the grader also includes a pump assembly 140 and an oil source 150. Specifically, the pump assembly 140 includes a first pump 141 which is capable of communicating with the cylinder assembly 110. The oil source 150 includes an oil outlet port 151 and an oil return port 152. The oil outlet port 151 communicates with the first pump 141, and the control valve group 130 enables the oil chamber of the at least one of the first working cylinders 111 to communicate with the oil return port 152. In the case that the oil pressure in the oil chamber of the at least one of the first working cylinders 111 is less than or equal to the preset value, the oil pressure in the oil chamber of the first working cylinder 111 is the standby oil pressure of the hydraulic control system for the grader 100.

In this embodiment, it is defined that the hydraulic control system for the grader 100 also includes the pump assembly 140 and the oil source 150. Specifically, the pump assembly 140 includes the first pump 141, and the first pump 141 is capable of communicating with the cylinder assembly 110 to adjust a working posture of the first working device 330.

The first pump 141 communicates with the oil outlet port 151 of the oil source 150. Before removing the lock pin 122, the control valve group 130 is used for communicating with the oil chamber of the at least one of the first working cylinders 111 and the oil return port 152 of the oil source 150 to release the pressure in the oil chamber of the at least one of the first working cylinders 111, thereby reducing the radial force applied to the lock pin 122, and thus achieving the unloading of the radial load on the lock pin 122. In this case, the driving member 121 is used for driving the lock pin 122 to be removed from the lock pin hole 321, the difficulty of removing the lock pin 122 is reduced, thereby achieving the rapid removal of the lock pin 122, and thus improving the construction efficiency.

Optionally, the first pump 141 includes an open-circuit piston pump. The open-circuit piston pump includes a load-sensing variable displacement pump or a fixed displacement pump. Specifically, the open-circuit piston pump includes the load-sensing variable displacement pump, which may automatically adjust its displacement according to a load of a working cylinder.

Optionally, the load-sensing variable displacement pump includes a load-sensing (LS) oil port, which communicates with a LS oil circuit of the control valve group 130 (a control passage for a load-sensing function).

Optionally, the fixed displacement pump includes a gear pump.

Optionally, the control valve group 130 includes an electrically controlled multi-way valve or a manually controlled multi-way valve.

Optionally, the control valve group 130 includes a load-sensing multi-way valve for a variable displacement system or a load-sensing multi-way valve for a fixed displacement system. The load-sensing multi-way valve for the variable displacement system matches with the load-sensing variable displacement pump, and the load-sensing multi-way valve for the fixed displacement system matches with the fixed displacement pump.

As shown in FIG. 1 and FIG. 3, in some embodiments, the plurality of first working cylinders 111 include the lift cylinder 113. Oil chambers of the lift cylinder 113 include a first chamber 160 and a second chamber 170. The control valve group 130 includes a first control valve 131 and/or a second control valve 132. The first control valve 131 is connected to the first chamber 160, and is configured to control communication or cutoff between the first chamber 160 and the oil return port 152. The second control valve 132 is connected to the second chamber 170, and is configured to control the communication or cutoff between the second chamber 170 and the oil return port 152.

In this embodiment, it is defined that the control valve group 130 includes the first control valve 131 and/or the second control valve 132. Specifically, the first control valve 131 is capable of controlling whether the first chamber 160 communicates with the oil return port 152, in other words, the first control valve 131 is capable of controlling whether to release the pressure of the first chamber 160. The second control valve 132 is capable of controlling whether the second chamber 170 communicates with the oil return port 152, in other words, the second control valve 132 is capable of controlling whether to release the pressure of the second chamber 170.

When it is necessary to remove the lock pin 122 change the lock pin hole 321, the first control valve 131 communicates with the first chamber 160 and the oil return port 152, and the second control valve 132 communicates with the second chamber 170 and the oil return port 152, so as to release the pressure in the first chamber 160 and the second chamber 170 of the lift cylinder 113, thereby reducing the radial load applied to the lock pin 122, and thus lowering the difficulty of removing the lock pin 122.

Optionally, the first control valve 131 includes a solenoid valve or a manual valve.

Optionally, the second control valve 132 includes a solenoid valve or a manual valve.

Optionally, in a case that both the first control valve 131 and the second control valve 132 are solenoid valves, when the grader 300 is in a working state, a first solenoid valve (the first control valve 131) and a second solenoid valve (the second control valve 132) are de-energized. As shown in FIG. 1 and FIG. 3, the first solenoid valve and the second solenoid valve are in a right position, and both the first chamber 160 and the second chamber 170 are cut off from the oil return port 152. When it is necessary to remove the lock pin 122, the first solenoid valve and the second solenoid valve are energized, and the first solenoid valve and the second solenoid valve are in a left position. At this time, the first chamber 160 and the second chamber 170 communicate with the oil return port 152, separately, and oil pressures in the first chamber 160 and the second chamber 170 are reduced to the standby oil pressure of the system. Therefore, the blade rests on the ground in a floating state, the unbalanced force of the lift cylinder 113 is eliminated, so that the unloading of the lock pin 122 is achieved. In this case, the lock pin 122 is driven to be removed.

Optionally, the lift cylinders 113 include the left lift cylinder and the right lift cylinder. The numbers of the first control valves 131 and the second control valves 132 are two, respectively. One pair of the first control valve 131 and the second control valve 132 respectively control whether the first chamber 160 and the second chamber 170 of the left lift cylinder are simultaneously depressurized. The other pair of the first control valve 131 and the second control valve 132 respectively control whether the first chamber 160 and the second chamber 170 of the right lift cylinder are simultaneously depressurized.

Optionally, the plurality of first working cylinders 111 also include the swing cylinder. The first control valve 131 and the second control valve 132 respectively control whether the first chamber 160 and the second chamber 170 of the swing cylinder are simultaneously depressurized. Specifically, it may be set according to actual requirements.

Optionally, each first working cylinder 111 also includes a first oil port and a second oil port. The first pump 141 may communicate with the first chamber 160 via the first oil port, and the first pump 141 may also communicate with the second chamber 170 via the second oil port, so as to adjust a working posture of the blade.

As shown in FIG. 5, in some embodiments, the plurality of first working cylinders 111 include the lift cylinder 113. The oil chambers of the lift cylinder 113 include the first chamber 160 and the second chamber 170. The control valve group 130 includes a third control valve 133 which is connected to the first pump 141 and the lift cylinder 113. The third control valve 133 includes a plurality of working positions which includes a first working position 1331 and a second working position 1332. In a case that the third control valve 133 is in the first working position 1331, the first chamber 160 and the second chamber 170 communicate with the oil return port 152, separately. In a case that the third control valve 133 is in the second working position 1332, one of the first chamber 160 and the second chamber 170 communicates with the first pump 141, and the other of the first chamber and the second chamber communicates with the oil return port 152.

In this embodiment, it is defined that an alternative method for placing the first working cylinder 111 in a floating state. Specifically, the control valve group 130 includes the third control valve 133 which is connected to the first pump 141 and the lift cylinder 113.

The third control valve 133 includes the plurality of working positions including the first working position 1331 and the second working position 1332. When the third control valve 133 is in the first working position 1331, the first chamber 160 and the second chamber 170 of the lift cylinder 113 communicate with the oil return port 152, separately, thereby releasing the pressure in the first chamber 160 and the second chamber 170. In other words, when it is necessary to remove the lock pin 122, the third control valve 133 is firstly placed in the first working position 1331. After the oil pressures in the first chamber 160 and the second chamber 170 drop below the preset value, the driving member 121 is controlled to drive the lock pin 122 to be removed, thereby reducing the difficulty of removing the lock pin 122.

When the third control valve 133 is in the second working position 1332, the first chamber 160 communicates with the first pump 141, and the second chamber 170 communicates with the oil return port 152; or, the second chamber 170 communicates with the first pump 141, and the first chamber 160 communicates with the oil return port 152. In other words, when the third control valve 133 is in the second working position 1332, the working posture of the blade may be adjusted upward or downward.

Optionally, the plurality of first working cylinders 111 also include the swing cylinder. By placing the third control valve 133 in different working positions, the swing cylinder is controlled to adjust the posture of the blade or be in the floating state.

Optionally, the third control valve 133 includes a directional control valve. The directional control valve includes a solenoid-operated directional control valve or a manual-operated directional control valve.

As shown in FIG. 5, in some embodiments, the plurality of working positions also include a third working position 1333. The hydraulic control system for the grader 100 also includes a hydraulic lock 180 located on a communication path between the third control valve 133 and the lift cylinder 113, and the hydraulic lock 180 may be opened or closed. In a case that the third control valve 133 is in the first working position 1331 or the second working position 1332, the hydraulic lock 180 is opened. In a case that the third control valve 133 is in the third working position 1333, the hydraulic lock 180 is closed, and any one of the first chamber 160 and the second chamber 170 is cut off from the first pump 141 and the oil return port 152.

In this embodiment, it is defined that the hydraulic control system for the grader 100 also includes the hydraulic lock 180. Specifically, the plurality of working positions also include the third working position 1333. When the third control valve 133 is in the third working position 1333, the first chamber 160 is cut off from the first pump 141 and the oil return port 152, the second chamber 170 is cut off from the first pump 141 and the oil return port 152. Consequently, the working position of the first working device 330 is locked.

Optionally, in a case that the directional control valve includes the solenoid-operated directional control valve, the solenoid-operated directional control valve includes a first valve body 137 and a second valve body 138. Specifically, when the first valve body 137 is de-energized and the second valve body 138 is energized with a maximum level current, the solenoid-operated directional control valve is in a lower position, a pilot oil circuit of the hydraulic lock 180 communicates with a pressure oil circuit, and the hydraulic lock 180 is opened. At this time, the first chamber 160 and the second chamber 170 communicate with an oil drainage circuit (the oil return port 152), and the lift cylinder 113 is floating, that is, the solenoid-operated directional control valve is in the first working position 1331.

When the first valve body 137 is energized and the second valve body 138 is de-energized, the solenoid-operated directional control valve is in an upper position. The pilot oil circuit of the hydraulic lock 180 communicates with the pressure oil circuit, and the hydraulic lock 180 is opened. At this time, the first chamber 160 communicates with the pressure oil circuit (the first pump 141), the second chamber 170 communicates with the oil return port 152, and the lift cylinder 113 descends for adjusting the blade downward. That is, the solenoid-operated directional control valve is in a first case of the first working position 1331.

When the first valve body 137 is de-energized and the second valve body 138 is energized with a medium level current, the solenoid-operated directional control valve is in a middle-lower position. The pilot oil circuit of the hydraulic lock 180 communicates with the pressure oil circuit, and the hydraulic lock 180 is opened. At this time, the second chamber 170 communicates with the pressure oil circuit (the first pump 141), the first chamber 160 communicates with the oil return port 152, and the lift cylinder 113 rises for adjusting the blade upward. That is, the solenoid-operated directional control valve is in a second case of the first working position 1331.

When the first valve body 137 is de-energized, the second valve body 138 is de-energized, the solenoid-operated directional valve is in a middle position, and the hydraulic lock 180 is closed. At this time, the lift cylinder 113 is locked. That is, the first chamber 160 does not communicate with the pressure oil circuit and the oil return port 152, the second chamber 170 does not communicate with the pressure oil circuit and the oil return port 152, and a position of the blade is locked, which is suitable for working conditions.

Optionally, the plurality of first working cylinders 111 also include the swing cylinder. The control valve group 130 also includes a sixth control valve. The sixth control valve communicates with the first pump 141 and the swing cylinder. The sixth control valve includes the solenoid-operated directional valve, and the solenoid-operated directional control valve includes a third valve body and a fourth valve body. When both the third valve body and the fourth valve body are de-energized, the solenoid-operated directional valve is in the middle position, the hydraulic lock 180 is closed, so that the swing cylinder is locked, and thus the blade position is locked, which is suitable for the working conditions.

When the third valve body is energized, the fourth valve body is de-energized, the solenoid-operated directional valve is in the upper position. The pilot oil circuit of the hydraulic lock 180 communicates with the pressure oil circuit, and the hydraulic lock 180 is opened. At this time, pressure oil is introduced into a rodless chamber of the swing cylinder, and a rod chamber of the swing cylinder communicates with the oil drainage circuit (the oil return port 152). The swing cylinder extends and is in a right-swing working position for adjusting the posture of the blade to the right.

When the third valve body is de-energized, the fourth valve body is energized, the solenoid-operated directional valve is in the lower position. At this time, the pilot oil circuit of the hydraulic lock 180 communicates with the pressure oil circuit, and the hydraulic lock 180 is opened. The pressure oil is introduced into the rod chamber of the swing cylinder, and the rodless chamber of the swing cylinder communicates with the oil drainage circuit. The swing cylinder retracts and is in a left-swing working position for adjusting the posture of the blade to the left.

The first valve body 137, the second valve body 138, the third valve body, and the fourth valve body are electrically connected to a display screen 310 of the grader 300. An action of each working hydraulic cylinder is controlled by energizing or de-energizing the respective valve body.

As shown in FIG. 1 and FIG. 5, in some embodiments, the grader 300 also includes a second working device 360. The driving member 121 includes a driving cylinder 123, and the cylinder assembly 110 also includes a second working cylinder 112 configured to connect to the second working device 360. The control valve group 130 also includes a fourth control valve 134 provided to the second working cylinder 112, and the fourth control valve 134 enables the second working cylinder 112 to communicate with the first pump 141 to increase a main oil pressure of the hydraulic control system for the grader 100. In a case that the fourth control valve 134 enables the second working cylinder 112 to communicate with the first pump 141, the control valve group 130 enables the driving cylinder 123 to communicate with the first pump 141, so as to drive the lock pin 122 to be removed from the lock pin hole 321.

In this embodiment, it is defined that the control valve group 130 also includes the fourth control valve 134. Specifically, the cylinder assembly 110 also includes the second working cylinder 112, and the second working cylinder 112 is used for connecting the second working device 360. Optionally, the second working device 360 includes a ripper, a dozer blade, a loose-earth rake, or a front wheel tilt mechanism, in other words, the second working cylinder 112 includes a ripper cylinder, a dozer blade cylinder, a loose-earth rake cylinder, or a front wheel tilt cylinder.

The driving member 121 is the driving cylinder 123, and the driving cylinder 123 is capable of communicating with the first pump 141. In other words, the lock pin 122 is driven by the driving cylinder 123 to be inserted into or removed from the lock pin hole 321.

The fourth control valve 134 is capable of controlling the communication or cutoff between the second working cylinder 112 and the first pump 141. When the fourth control valve 134 enables the second working cylinder 112 to communicate with the first pump 141, that is, when the pressure oil is introduced into the oil chamber of the second working cylinder 112, the main oil pressure of an entire hydraulic control system is increased.

When it is necessary to remove the lock pin 122, the pressure oil is firstly introduced into the second working cylinder 112 via the fourth control valve 134, so that the main oil pressure of the entire hydraulic control system is increased. Subsequently, an oil chamber of the driving cylinder 123 communicates with the first pump 141 to drive the lock pin 122 to be removed from the lock pin hole 321, so that a removing force of the lock pin is increased to satisfy a force required for the lock pin 122 to be removed, thereby achieving the rapid removal of the lock pin 122.

In addition, before removing the lock pin 122, the pressure oil is introduced into the second working cylinder 112 to ensure that the removing force of the lock pin is greater than an insertion force of the lock pin. Compared to the related art where the insertion force of the lock pin 122 is greater than the removing force of the lock pin 122 to make the lock pin 122 be wedged into a taper sleeve, the radial load applied by the taper sleeve in the lock pin hole 321 to the lock pin 122 may be further reduced. Consequently, as the apparatus usage time increases, when the required removing force of the lock pin increases due to factors such as wear of the lock pin 122, wear of the lock pin 122 and the taper sleeve of the lock pin 122, poor lubrication, and rust, the difficulty of removing the lock pin 122 is reduced, and thus satisfying the removing force required for the lock pin 122 to be removed.

Specifically, the removing force required for removing the lock pin 122 depends on the main oil pressure of the system, which may be calculated according to a formula:

F out = P out × S b ;

where, the F_out is the removing force of the lock pin 122, the P_out is an oil pressure for removing the lock pin 122, the S_b is a cross-sectional area of a first oil chamber 230 of the driving cylinder 123 minus a cross-sectional area of the piston rod of the driving cylinder 123.

When the main oil pressure of the system increases, the oil pressure for removing the lock pin 122 correspondingly increases, thereby increasing the removing force of the lock pin.

Optionally, the fourth control valve 134 includes a solenoid valve. The solenoid valve is controlled to be energized, that is, the second working cylinder 112 is controlled to communicate with the first pump 141.

Optionally, the driving cylinder 123 includes the first oil chamber 230 and the second oil chamber 240. When the first oil chamber 230 communicates with the first pump 141, the driving cylinder 123 drives the lock pin 122 to be inserted into the lock pin hole 321. When the second oil chamber 240 communicates with the first pump 141, the driving cylinder 123 drives the lock pin 122 to be removed from the lock pin hole 321. That is, the first oil chamber 230 is a rodless chamber, and the second oil chamber 240 is a rod chamber.

Optionally, there are a plurality of second working cylinders 112 and a plurality of fourth control valves 134. Each fourth control valve 134 is connected to one second working cylinder 112. When it is necessary to remove the lock pin 122, the plurality of fourth control valves 134 control the plurality of second working cylinders 112 to communicate with the first pump 141.

In other words, the pressure oil is introduced into the plurality of second working cylinders 112, so that the removing force of the lock pin is significantly greater than the insertion force of the lock pin. Compared to the related art where the insertion force of the lock pin 122 is greater than the removing force of the lock pin 122 to make the lock pin 122 be wedged into the taper sleeve, the radial load applied by the taper sleeve in the lock pin hole 321 to the lock pin 122 may be further reduced, the difficulty of removing the lock pin 122 is further reduced, thereby satisfying a force required for inserting and removing the lock pin 122 throughout its entire lifecycle, and thus effectively solving a problem of difficulty in removing the lock pin 122.

Optionally, the hydraulic control system for the grader 100 also includes a plurality of shuttle valves 190 and a plurality of compensation valves 220. There are the plurality of third control valves 133, and the plurality of third control valves 133 are connected to the plurality of first working cylinders 111, respectively. The plurality of compensation valves 220 are respectively located at outlets of the plurality of third control valves 133 and the plurality of fourth control valves 134.

Specifically, a workload of each first working cylinder 111 communicates with an oil inlet of a corresponding shuttle valve 190 via the third control valve 133 connected to the first working cylinder 111. Through a pressure comparison function of the shuttle valve 190, maximum workloads of all working cylinders are output to the plurality of compensation valves 220. Through the compensation valve 220, outlet oil pressures of the plurality of third control valves 133 and the plurality of fourth control valves 134 are consistent and maximized, thereby ensuring an oil pressure required to simultaneously drive all the working cylinders to operate.

Optionally, the hydraulic control system for the grader 100 also includes a second overflow valve 210. The second overflow valve 210 communicates with a LS oil port of the first pump 141 and the oil return port 152, so that a pressure of a LS oil circuit via the second overflow valve 210 is limited, thereby controlling a maximum oil pressure of the system, and thus protecting the system.

In addition, through oil pressure feedback from the LS oil port, the displacement of the first pump 141 is adjusted to satisfy a flow requirement for operation of the cylinder assembly 110.

As shown in FIG. 3, in some embodiments, the grader 300 also includes a fan 340 and a hydraulic motor 340. The hydraulic motor 340 is configured to drive the fan 340. The driving member 121 includes the driving cylinder 123, and the pump assembly 140 also includes a second pump 142 communicating with the hydraulic motor 340. The control valve group 130 also includes a speed control valve 135 provided to the hydraulic motor 340, and the speed control valve 135 includes a first state and a second state. When the speed control valve 135 is in the first state, a rotational speed of the hydraulic motor 340 is a first rotational speed value, and the control valve group 130 enables the driving cylinder 123 to communicate with the second pump 142 to drive the lock pin 122 to be removed from the lock pin hole 321. When the speed control valve 135 is in the second state, the rotational speed of the hydraulic motor 340 is a second rotational speed value, and the second rotational speed value is less than the first rotational speed value.

In this embodiment, it is defined that the control valve group 130 also includes the speed control valve 135. Specifically, the grader 300 includes the hydraulic motor 340 and the fan 340, and the hydraulic motor 340 is configured to drive the fan 340 to rotate to dissipate heat for an apparatus to be cooled.

The hydraulic motor 340 communicates with the second pump 142, and the second pump 142 is capable of communicating with the driving cylinder 123. When the rotational speed of the hydraulic motor 340 increases, the main oil pressure in the oil circuits of the oil source 150, the second pump 142, and the driving cylinder 123 is increased, that is, the main oil pressure of the second pump 142 is increased.

The speed control valve 135 has the first state and the second state. The rotational speed of the hydraulic motor 340 when the speed control valve 135 is in the first state is greater than the rotational speed of the hydraulic motor 340 when the speed control valve 135 is in the second state. In other words, when it is necessary to remove the lock pin 122, the speed control valve 135 is set to be in the first state, so that the hydraulic motor 340 operates at a high rotational speed, thereby increasing the main oil pressure of the second pump 142, and thus increasing the removing force of the lock pin to satisfy the force required for removing the lock pin 122 to achieve the rapid removal of the lock pin 122.

In addition, before removing the lock pin 122, by increasing the rotational speed of the hydraulic motor 340, the removing force of the lock pin is greater than the insertion force of the lock pin. Compared to the related art where the insertion force of the lock pin 122 is greater than the extraction force of the lock pin 122 to make the lock pin 122 be wedged into the taper sleeve, the radial load applied by the taper sleeve in the lock pin hole 321 to the lock pin 122 may further be reduced. Consequently, as the apparatus usage time increases, when the required extraction force of the lock pin increases due to factors such as the wear of the lock pin 122 and the taper sleeve of the lock pin 122, the poor lubrication, and the rust, the difficulty for removing the lock pin 122 is reduced, thereby satisfying the extraction force required for the lock pin 122 to be removed.

When the lock pin 122 is removed, the speed control valve 135 is set to be in the second state, so that the hydraulic motor 340 operates at a low rotational speed.

Optionally, the second state includes an exit control state. In other words, when the removal of the lock pin 122 is completed, control of the speed control valve 135 is exited.

Optionally, the speed control valve 135 includes a proportional solenoid valve. When the proportional solenoid valve is de-energized, the rotational speed of the hydraulic motor 340 is maximized, so that the removing force of the lock pin is significantly greater than the insertion force, thereby satisfying the force required for inserting and removing the lock pin 122 throughout its entire lifecycle.

That is, the rotational speed of the hydraulic motor 340 may be adjusted by de-energizing the proportional solenoid valve or exit the control thereof.

Optionally, the rotational speed of the hydraulic motor 340 may be adjusted by controlling a magnitude of an applied current. Specific implementation may be set according to actual requirements.

Optionally, the first pump 141 and the second pump 142 may communicate with a same oil source 150, or to different oil source 150.

Optionally, the second pump 142 may obtain an oil source 150 of hydraulic oil from systems with independent oil source 150, such as a brake hydraulic system or a transmission hydraulic system. Specific implementation may be set according to actual requirements.

Optionally, the second pump 142 includes a variable displacement pump or the fixed displacement pump.

Specifically, when the second pump 142 includes the displacement variable pump, the variable displacement pump includes a load-sensing open-circuit piston pump. When the second pump 142 includes the fixed displacement pump, the fixed displacement pump includes a gear pump.

As shown in FIG. 1, FIG. 3, and FIG. 5, in some embodiments, the driving cylinder 123 includes the first oil chamber 230 and the second oil chamber 240. The control valve group 130 also includes a fifth control valve 136 which is connected to the driving cylinder 123 and the pump assembly 140. The fifth control valve 136 enables the first oil chamber 230 or the second oil chamber 240 to communicate with the pump assembly 140. In a case that the fifth control valve 136 enables the first oil chamber 230 to communicate with the pump assembly 140, the driving cylinder 123 drives the lock pin 122 to be inserted into any one of the lock pin holes 321. The hydraulic control system for the grader 100 also includes a first overflow valve 250 which communicates with the first oil chamber 230, and the first overflow valve 250 may communicate with the oil return port 152.

In this embodiment, it is defined that the control valve group 130 also includes the fifth control valve 136. Specifically, the fifth control valve 136 communicates with the driving cylinder 123 and the pump assembly 140. The fifth control valve 136 enables the pump assembly 140 to communicate with the first oil chamber 230 of the driving cylinder 123 or the second oil chamber 240 of the driving cylinder 123, so as to drive the lock pin 122 to be inserted into or removed from the lock pin hole 321.

Specifically, when it is necessary to insert the lock pin 122 into the lock pin hole 321, the fifth control valve 136 enables the pump assembly 140 to communicate with the first oil chamber 230, that is, the first oil chamber 230 is a rodless chamber.

When it is necessary to remove the lock pin 122, the fifth control valve 136 enables the pump assembly 140 to communicate with the second oil chamber 240, that is, the second oil chamber 240 is a rod chamber.

Optionally, the fifth control valve 136 includes the solenoid valve. The pump assembly 140 is controlled to communicate with the first oil chamber 230 or the second oil chamber 240 by energizing or de-energizing the solenoid valve.

The hydraulic control system for the grader 100 also includes the first overflow valve 250. Specifically, the first overflow valve 250 communicates with the first oil chamber 230 and the oil return port 152.

When it is necessary to insert the lock pin 122 into the lock pin hole 321, the fifth control valve 136 enables the pump assembly 140 to communicate with the first oil chamber 230. After the lock pin 122 is fully inserted, since the first overflow valve 250 is provided, when the oil pressure in the first oil chamber 230 further increases, the first overflow valve 250 will be opened to overflow to make an oil pressure in the first oil chamber 230 maintain stable, so that the force required for inserting the lock pin 122 is satisfied while preventing the insertion force from being too large, thereby preventing the lock pin 122 from being over-wedged into the taper sleeve in the lock pin hole 321, and thus the clamping force between the taper sleeve and the lock pin 122 is reduced. Therefore, the radial force that the taper sleeve applied on the lock pin 122 is reduced when it is necessary to remove the lock pin 122, thereby lowering the difficulty of removing the lock pin 122.

Specifically, the insertion force is calculated according to a formula:

F i ⁢ n = P i ⁢ n × S a ;

where, the F_in is the insertion force of the lock pin, the P_in is the oil pressure of the first oil chamber 230, and the S_a is a cross-sectional area of the first oil chamber 230 of the driving cylinder 123.

By setting the first overflow valve 250, the oil pressure of the first oil chamber 230 may be maintained constant. That is, the insertion force of the lock pin is a fixed value. Therefore, the clamping force between the taper sleeve and the lock pin 122 is greatly reduced, so that solving a problem that a control pressure of the driving cylinder 123 is a fixed value or the insertion force of the lock pin will increase proportionally when the removing force of the lock pin increases, thereby satisfying a required insertion force of the lock pin while preventing the insertion force from being too large.

As shown in FIG. 1, FIG. 3, and FIG. 5, in some embodiments, the hydraulic control system for the grader 100 also includes a filter assembly 280 and a flow restricting orifice 260. An inlet of the filter assembly 280 communicates with the pump assembly 140, and an outlet of the filter assembly 280 may communicate with the cylinder assembly 110 and the driving cylinder 123. An inlet of the flow restricting orifice 260 communicates with an outlet of the filter assembly 280 via a first pipeline 270, and an outlet of the flow restricting orifice 260 communicates with the driving cylinder 123. A flow cross-sectional area of the flow restricting orifice 260 is less than a flow cross-sectional area of the first pipeline 270.

In this embodiment, it is defined that the hydraulic control system for the grader 100 also includes the filter assembly 280. Specifically, oil flowing out of the pump assembly 140 is filtered by the filter assembly 280 before entering the cylinder assembly 110 or the driving cylinder 123, thereby filtering impurities in the hydraulic oil to ensure cleanliness of the oil in the entire system, and thus ensuring reliability and stability of operation of the entire system.

The hydraulic control system for the grader 100 also includes the flow restricting orifice 260. Specifically, two ends of the flow restricting orifice 260 communicate with the filter assembly 280 and the driving cylinder 123, respectively. Since the flow cross-sectional area of the flow restricting orifice 260 is less than the flow cross-sectional area of the first pipeline 270, a flow rate of the hydraulic oil entering the driving cylinder 123 is restricted. Therefore, a flow rate required for inserting and removing the lock pin 122 is satisfied while preventing an excessive flow rate of the hydraulic oil entering the fifth control valve 136 when a system pressure is high, which will cause a high energy consumption of the system, and thus ensuring stable operation of the system.

Optionally, the flow restricting orifice 260 includes a damping hole.

Optionally, the hydraulic control system for the grader 100 also includes a check valve. The check valve is located between the flow restricting orifice 260 and the fifth control valve 136, and is used for controlling an unidirectional flow from the filter assembly 280 to the driving cylinder 123, thereby providing reverse locking of the driving cylinder 123 in a shutdown state, that is, maintaining a pressure in the first oil chamber 230 of the driving cylinder 123, and thus preventing the lock pin 122 from being removed from the lock pin hole 321.

Specifically, when it is necessary to insert the lock pin 122 into the lock pin hole 321, the solenoid valve (the fifth control valve 136) is de-energized, the hydraulic oil passes through the flow restricting orifice 260, the check valve and the solenoid valve and enters the first oil chamber 230, and the hydraulic oil in the second oil chamber 240 flows to the oil return port 152.

When the it is necessary to remove the lock pin 122, the solenoid valve is energized, the hydraulic oil passes through the flow restricting orifice 260, the check valve and the solenoid valve and enters the second oil chamber 240, and the hydraulic oil in the first oil chamber 230 flows to the oil return port 152.

As shown in FIG. 2, FIG. 4, and FIG. 6, in some embodiments, the hydraulic control system for the grader 100 also includes a detection member 290. The detection member 290 is disposed on the lock pin assembly 120 for detecting whether the lock pin 122 is inserted into or removed from the lock pin hole 321.

In this embodiment, it is defined that the hydraulic control system for the grader 100 also includes the detection member 290. Specifically, the detection member 290 is provided for the lock pin assembly 120, and the detection member 290 is capable of detecting whether the lock pin 122 is inserted into or removed from the lock pin hole 321. That is, the detection member 290 detects whether the lock pin 122 is in an inserted state or a removing state, thereby ensuring a smooth operation of the grader 300.

Optionally, the detection member 290 is integrated on the driving cylinder 123, and is configured to detect a displacement of a piston rod of the driving cylinder 123 to identify whether the lock pin 122 is in the inserted state or the extracted state.

Optionally, the detection member 290 includes sensors such as a displacement sensor or a proximity switch, or the like.

According to a second aspect of the present application, a grader 300 is provided. The grader 300 includes the hydraulic control system for the grader 100 provided in any one of the above embodiments, thereby having all the beneficial technical effects of the hydraulic control system for the grader 100, and details will not be described herein.

As shown in FIG. 2, FIG. 4, and FIG. 6, in some embodiments, the grader 300 also includes the display screen 310. The display screen 310 is electrically connected to the control valve group 130.

In this embodiment, it is defined that the grader 300 also includes the display screen 310. Specifically, the display screen 310 is electrically connected to the control valve group 130, and the display screen 310 controls an action of the cylinder assembly 110 through the control valve group 130, so that it is convenient to operate. Optionally, the grader 300 also includes a controller. The controller is electrically connected to the control valve group 130.

As shown in FIG. 10, in a specific embodiment, an operation method for removing the lock pin (the hydraulic control method for the grader) includes:

step 202: checking whether a vehicle speed is zero, and if the vehicle speed is zero, entering a control program for removing the lock pin.

This prevents the lock pin from being removed during driving to avoid affecting driving safety.

step 204: controlling four solenoid valves of a floating valve group to be energized to enable the left lift cylinder and the right lift cylinder to float to allow the blade to land under its own weight, to make the lock pin be unloaded.

step 206: energizing one solenoid valve in the control valve group (for any one of the ripper, the dozer blade, the loose-earth rake, or the front wheel tilt hydraulic cylinder to increase the main oil pressure of the system.

This provides sufficient oil pressure for removing the lock pin.

step 208: controlling a lock pin control solenoid valve to be energized to remove the lock pin, and entering a next step after detecting that the lock pin is removed through a displacement sensor of the lock pin and the piston rod of the hydraulic cylinder.

step 210: controlling the four solenoid valves of the floating valve group to be de-energized, or one solenoid valve in the control valve group to be de-energized to exit the floating state, to make the main oil pressure of the system return to the previous level.

In this embodiment, the floating valve group includes a plurality of first control valves and a plurality of second control valves. The four solenoid valves of the floating valve group are controlled to be energized, that is, the two first control valves and two second control valves are controlled to be energized, so that the oil chambers of two first working cylinders communicate with the oil return port to depressurize the pressure.

One solenoid valve in the control valve group is energized, that is, the fourth control valve is controlled to be energized, so that the pressure oil is introduced into the second working cylinder.

The left lift cylinder and the right lift cylinder are the two first working cylinders.

The lock pin control solenoid valve is the fifth control valve, and the displacement sensor of the lock pin and the piston rod of the hydraulic cylinder is the detection member.

As shown in FIG. 11, in another specific embodiment, the operation method for removing the lock pin (the hydraulic control method for the grader) includes:

step 302: checking whether the vehicle speed is zero, if the vehicle speed is zero, entering the lock pin control program.

This prevents the lock pin from being removed during driving to avoid affecting the driving safety.

step 304: controlling the four solenoid valves of the floating valve group to be energized to enable the left lift cylinder and the right lift cylinder to float to allow the blade to land under its own weight, to make the lock pin be unloaded.

step 306: controlling a fan 340 speed control solenoid valve to be de-energized to increase a main oil pressure of a fan 340 pump.

step 308: controlling the lock pin control solenoid valve to be energized to remove the lock pin, and entering a next step after detecting that the lock pin is removed through the displacement sensor of the lock pin and the piston rod of the hydraulic cylinder.

step 310: controlling the four solenoid valves of the floating valve group to be de-energized and exiting control the fan 340 speed control solenoid valve to exit the floating state, to make the main oil pressure of the system return to the previous level.

In this embodiment, the floating valve group includes the plurality of first control valves and the plurality of second control valves. The four solenoid valves of the floating valve group are controlled to be energized, that is, the two first control valves and the two second control valves are controlled to be energized, so that the oil chambers of the two first working cylinders communicate with the oil return port to release the pressure.

The left lift cylinder and the right lift cylinder are the two first working cylinders.

The fan 340 speed control solenoid valve is the solenoid valve. The fan 340 pump is the second pump.

The lock pin control solenoid valve is the fifth control valve, and the displacement sensor of the lock pin and the piston rod of the hydraulic cylinder is the detection member.

As shown in FIG. 12, in still another specific embodiment, the operation method for removing the lock pin (the hydraulic control method for the grader) includes:

step 402: checking whether the vehicle speed is zero, if the vehicle speed is zero, entering the lock pin control program.

This prevents the lock pin from being removed during driving to avoid affecting the impact of the driving safety.

step 404: controlling multi-way valves D1 and D2 to energize a maximum level current and C1 and C2 to be de-energized, to enable the left lift cylinder and the right lift cylinder to float to allow the blade to land under its own weight, to make the lock pin be unloaded.

step 406: controlling a multi-way valve D4 to be energized and C4 to be de-energized to increase the main oil pressure of the system.

step 408: energizing the lock pin control solenoid valve to remove the lock pin, and entering a next step after detecting that the lock pin is removed through the displacement sensor of the lock pin and the piston rod of the hydraulic cylinder.

step 410: controlling the multi-way valves D1, D2, D4 to be de-energized to exit the floating state, to make the main oil pressure of the system return to the previous level.

In this embodiment, the multi-way valve includes the third control valve and the fourth control valve. The number of the third control valves is two, and each the third control valve is connected to a different first working cylinder. The C1 and the C2 are the first valve bodies of the two third control valves, and the D1 and the D2 are the second valve bodies of the two third control valves.

The fourth control valve includes a solenoid-operated directional control valve. The solenoid-operated directional control valve includes a fifth valve body and a sixth valve body, the C4 is the fifth valve body, and the D4 is the sixth valve body.

The lock pin control solenoid valve is the fifth control valve, and the displacement sensor of the lock pin and the piston rod of the hydraulic cylinder is the detection member.

According to a third aspect of the present application, as shown in FIG. 9, the hydraulic control method for the grader is provided. The grader includes a swing frame assembly, a first working device, a cylinder assembly, and a lock pin assembly. The cylinder assembly is connected to the swing frame assembly and the first working device. The cylinder assembly includes a plurality of first working cylinders, and the swing frame assembly is provided with a plurality of lock pin holes. The lock pin assembly includes a driving member and a lock pin connected to each other, and the lock pin is configured to be inserted into or removed from any one of the plurality of lock pin holes when driven by the driving member. The hydraulic control method includes:

step 102: performing pressure relief on an oil chamber of at least one of the first working cylinders to make an oil pressure in the oil chamber of the at least one of the first working cylinders be less than or equal to a preset value.

step 104: controlling the driving member to drive the lock pin to be removed from the lock pin hole.

The hydraulic control method for the grader is provided by the embodiments of the present application. Specifically, the grader includes the swing frame assembly, the first working device, the cylinder assembly and the lock pin assembly. The cylinder assembly is connected to the swing frame assembly and the first working device. Optionally, the first working device includes a blade.

The swing frame assembly is provided with the plurality of lock pin holes. The lock pin assembly includes the lock pin and the driving member connected to each other. The lock pin is configured to be inserted into or removed from any one of the lock pin holes when driven by the driving member, thereby enabling the first working device to switch between different working postures by changing the lock pin hole, and thus allowing it to operate under various conditions such as earthwork leveling, ditch excavation, and slope trimming.

When it is necessary to remove the lock pin from the lock pin hole to change the lock pin hole, due to imbalance in pressures among the plurality of first working cylinders in the cylinder assembly, a significant radial load is applied to the lock pin. Moreover, as a usage time of the apparatus increases, or the first working device and bearings of the swing frame assembly wear out, or factors like this, resulting in the pressure imbalance among various hydraulic cylinders under working conditions intensifies, thereby making it difficult to remove the lock pin, and thus affecting construction efficiency.

The cylinder assembly includes the plurality of first working cylinders. Optionally, the plurality of first working cylinders include lift cylinders and a swing cylinder. The lift cylinders include a left lift cylinder and a right lift cylinder.

Before removing the lock pin, pressure relief is performed on the oil chamber of the at least one of the first working cylinders to reduce the oil pressure in the oil chamber of the at least one of the first working cylinders. When the oil pressure in the oil chamber of the at least one of the first working cylinders is less than or equal to the preset value, the driving member is controlled to drive the lock pin to be removed from the lock pin hole.

In other words, before removing the lock pin, the pressure relief is performed on the at least one of the first working cylinders to make the at least one of the first working cylinders be in a floating state, thereby reducing a radial force applied to the lock pin, and thus achieving an unloading of the radial load on the lock pin. In this case, the driving member is controlled to drive the lock pin to be removed from the lock pin hole, so that the difficulty of removing the lock pin is reduced, thereby achieving rapid removal of the lock pin, and thus improving the construction efficiency.

Optionally, when the oil pressure in the oil chamber of the at least one of the first working cylinders is less than or equal to the preset value, the oil pressure in the oil chamber of the at least one of the first working cylinders is a standby oil pressure of a system, or the oil pressure in the oil chamber of the at least one of the first working cylinders equals to 0 MPa.

The oil in at least one of the first working cylinders is released to an oil return port of an oil source. When the oil pressure in the oil chamber of the at least one of the first working cylinders is less than or equal to the preset value, the oil pressure in the oil chamber of the at least one of the first working cylinders is the standby oil pressure of the system.

When the oil in the at least one of the first working cylinders is released to another oil tank, the oil pressure in the oil chamber of the at least one of the first working cylinders may be 0 MPa when the oil pressure in the oil chamber of the at least one of the first working cylinders 111 is less than or equal to the preset value, that is, a pressure in the at least one of the first working cylinders is eliminated, thereby further reducing the radial force applied to the lock pin, and thus achieving complete unloading of the radial load on the lock pin.

In other words, the oil chamber of the at least one of the first working cylinders may communicate with the oil return port of the oil source or another oil tank via the control valve group, so as to release the pressure in the oil chamber of the at least one of the first working cylinders.

Optionally, the preset value is 1 MPa or 2 MPa.

Optionally, both the left lift cylinder and the right lift cylinder may be simultaneously placed in a floating state. Alternatively, the left lift cylinder and the swing cylinder may be simultaneously placed in the floating state, or the right lift cylinder and the swing cylinder may be simultaneously placed in the floating state, or the left lift cylinder, the right lift cylinder, and the swing cylinder may be simultaneously placed in the floating state, so that the radial load applied to the lock pin due to the pressure imbalance of the cylinders is minimized, thereby further achieving the rapid removal of the lock pin.

In some embodiments, the driving member includes a driving cylinder. The grader also includes a second working device 360, a first pump, and a second working cylinder. The first pump communicates with the driving cylinder, and the second working cylinder is configured to connect the second working device 360. Before the controlling driving member to drive the lock pin to be removed from the lock pin hole, the hydraulic control method also includes: controlling the second working cylinder to communicate with the first pump.

In this embodiment, the second working cylinder is configured to connect the second working device 360. Optionally, the second working device 360 includes a ripper, a dozer blade, a loose-earth rake, or a front wheel tilt mechanism, in other words, the second working cylinder includes a ripper hydraulic cylinder, a dozer blade hydraulic cylinder, a loose-earth rake hydraulic cylinder, or a front wheel tilt hydraulic cylinder.

The driving member is the driving cylinder. The driving cylinder may communicate with the first pump. In other words, the driving cylinder drives the lock pin to be inserted into or removed from the lock pin hole.

When it is necessary to remove the lock pin, the second working cylinder is controlled to communicate with the first pump. That is, pressure oil is introduced into the second working cylinder to increase a main oil pressure of an entire hydraulic control system. Subsequently, controlling an oil chamber of the driving cylinder to communicate with the first pump to drive the lock pin to be removed from the lock pin hole. Therefore, a removing force of the lock pin is increased to satisfy a force required for the lock pin to be removed, thereby achieving the rapid removal of the lock pin.

In addition, before removing the lock pin, the pressure oil is introduced into the second working cylinder, so that the removing force of the lock pin is greater than an insertion force of the lock pin. Compared to the related art where the insertion force of the lock pin is greater than the removing force to make the lock pin to be wedged into a taper sleeve, the radial load applied by the taper sleeve in the lock pin hole to the lock pin may be further reduced. Consequently, as apparatus usage time increases, when the required removing force of the lock pin increases due to factors such as wear of the lock pin 122, wear of the taper sleeve of the lock pin 122, poor lubrication, and rust, the difficulty of removing the lock pin is reduced, and thus satisfying the removing force required for the lock pinto be removed.

Specifically, the removing force required for removing the lock pin depends on the main oil pressure of the system, which may be calculated according to a formula:

F out = P out × S b ;

where, the F_out is the removing force of the lock pin, the P_out is an oil pressure for removing the lock pin, and the S_b is a cross-sectional area of a first oil chamber of the driving cylinder minus a cross-sectional area of a piston rod of the driving cylinder.

When the main oil pressure of the system increases, the oil pressure for removing the lock pin correspondingly increases, thereby increasing the removing force of the lock pin.

Optionally, the driving cylinder includes the first oil chamber and a second oil chamber. When the first oil chamber communicates with the first pump, the driving cylinder drives the lock pin to be inserted into the lock pin hole. When the second oil chamber communicates with the first pump, the driving cylinder drives the lock pin to be removed from the lock pin hole. That is, the first oil chamber is a rodless chamber, and the second oil chamber is a rod chamber.

Optionally, there are a plurality of second working cylinders. When it is necessary to remove the lock pin, the plurality of second working cylinders are controlled to communicate with the first pump. That is, the pressure oil is introduced into the plurality of second working cylinders, so that the removing force of the lock pin is significantly greater than the insertion force of the lock pin. Compared to the related art where the insertion force of the lock pin is greater than the extraction force of the lock pin 122 to make the lock pin be wedged into the taper sleeve, the radial load applied by the taper sleeve in the lock pin hole to the lock pin is further reduced, so that the difficulty of removing the lock pin is further reduced to satisfy the force required for inserting and removing the lock pin throughout its lifecycle, and thus effectively solving a problem of difficulty in removing the lock pin.

In some embodiments, the driving member includes the driving cylinder. The grader also includes a fan 340, a hydraulic motor and a second pump. The hydraulic motor is configured to drive the fan 340, and the second pump communicates with the hydraulic motor and the driving cylinder. Before the controlling the driving member to drive the lock pin to be removed from the lock pin hole, the hydraulic control method also includes: controlling the hydraulic motor to operate at a first speed value; and after the controlling the driving member to drive the lock pin to be removed from the lock pin hole, the hydraulic control method also includes: controlling the hydraulic motor to operate at a second speed value. The second speed value is less than the first speed value.

In this embodiment, the grader includes the hydraulic motor and the fan 340. The hydraulic motor is configured to drive fan 340 to rotate to dissipate heat for an apparatus to be cooled.

The hydraulic motor communicates with the second pump, and the second pump is capable of communicating with the driving cylinder. When increasing the rotational speed of the hydraulic motor, the main oil pressure of the oil circuits of the oil source, the second pump and the driving cylinder is increased, that is, the main oil pressure of the second pump is increased.

In addition, before removing the lock pin, by increasing the rotational speed of the hydraulic motor, the removing force of the lock pin is greater than the insertion force of the lock pin. Compared to the related art where the insertion force of the lock pin is greater than the removing force of the lock pin 122 to make the lock pin to be wedged into the taper sleeve, the radial load applied by the taper sleeve in the lock pin hole to the lock pin may further reduced. Consequently, as the apparatus usage time increases, when the required removing force of the lock pin increases due to factors such as wear of the lock pin 122, wear of the taper sleeve of the lock pin 122, poor lubrication, and rust, the difficulty of removing the lock pin is reduced, and thus satisfying the removing force required for the lock pin to be removed.

After removing the lock pin, the hydraulic motor operates at a low speed.

In the description of this specification, terms such as “connect”, “install”, “fix”, should be understood broadly. For example, the “connect” may be a fixed connection, a detachable connection, or an integrated connection; or it is a direct connection or an indirect connection through an intermediate medium. For those with ordinary skill in the art, specific meanings of the above terms in the present application are understood according to specific situations.

In the description of this specification, terms such as “an embodiment”, “some embodiments”, “specific embodiments” indicate that specific features, structures, materials, or characteristics described with reference the embodiment or example are included in at least one embodiment or example of the present application. In this specification, schematic expression of the above terms does not necessarily refer to a same embodiment or instance. Moreover, the described specific features, structures, materials, or characteristics may be combined in any one of or more of the embodiments or examples in a suitable manner.

The above are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modifications, equivalent substitutions, improvements, or the like made within the spirit and principles of the present application shall be included within the protection scope of the present application.