PRESSURE SOURCE UNIT

Description

TECHNICAL FIELD

The present disclosure relates to a pressure source unit for use in a hydraulic circuit.

BACKGROUND ART

Conventionally, there is a known pressure source unit including a hydraulic pump and an electric motor. For example, FIG. 6 of Patent Literature 1 discloses a pressure source unit installed on an injection molding machine. In Patent Literature 1, the pressure source unit is referred to as a “hydraulic pressure generator”.

Specifically, the pressure source unit includes a sleeve that is located between a pump casing of a hydraulic pump and a motor casing of an electric motor. The sleeve connects the pump casing and the motor casing to each other. Inside the sleeve, the rotating shaft of the hydraulic pump and the output shaft of the electric motor are coupled to each other. The sleeve is fixed to the injection molding machine via a bracket.

CITATION LIST

Patent Literature

• • PTL 1: Japanese Laid-Open Patent Application Publication No. H 11-314257

SUMMARY OF INVENTION

Technical Problem

However, in the above-described pressure source unit, since the electric motor is positioned in the air, there is a desire to suppress vibration of the electric motor.

In view of the above, an object of the present disclosure is to provide a pressure source unit that makes it possible to suppress vibration of its electric motor.

Solution to Problem

The present disclosure provides a pressure source unit installed on a machine, the pressure source unit including: a hydraulic pump including a rotating shaft and a pump casing; an electric motor including an output shaft and a motor casing, the output shaft being coupled to the rotating shaft; and a connecting structure that is located between the pump casing and the motor casing and that connects the pump casing and the motor casing to each other. The pump casing or the connecting structure is fixed to the machine. The motor casing is supported by the machine via an elastic body.

Advantageous Effects of Invention

The present disclosure provides a pressure source unit that makes it possible to suppress vibration of its electric motor.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view of a pressure source unit according to one embodiment.

FIG. 2 is a sectional view of a variation of the pressure source unit.

DESCRIPTION OF EMBODIMENTS

FIG. 1 shows a pressure source unit 1 according to one embodiment. The pressure source unit 1 is installed on a machine 9. FIG. 1 shows only part of the machine 9. For example, the machine 9 may be a construction machine such as a hydraulic excavator or a wheel loader, or may be an industrial machine such as an injection molding machine or press equipment.

Specifically, the pressure source unit 1 includes: a hydraulic pump 2; an electric motor 6; and a connecting structure 5 between the hydraulic pump 2 and the electric motor 6. The hydraulic pump 2 and the electric motor 6 are positioned side by side laterally to each other. In the present embodiment, the hydraulic pump 2 and the electric motor 6 are located coaxially.

In the present embodiment, the hydraulic pump 2 is a swash plate pump that is one type of axial piston pump. Alternatively, the hydraulic pump 2 may be a bent axis pump that is another type of axial piston pump. Further alternatively, the hydraulic pump 2 may be a different type of pump, such as a vane pump, a gear pump, or a screw pump.

The hydraulic pump 2 includes: a rotating shaft 21 extending in the horizontal direction; and a pump casing 22, which supports the rotating shaft 21 via bearings 23 and 24 such that the rotating shaft 21 is rotatable. The pump casing 22 is a hollow casing, and a valve plate 31, a cylinder block 32, and a swash plate 36 are accommodated in the pump casing 22.

To be more specific, the pump casing 22 includes: a front wall penetrated by the rotating shaft 21; a valve cover that faces the front wall in the axial direction of the rotating shaft 21; and a peripheral wall that surrounds a space between the front wall and the valve cover. The valve cover includes a suction passage and a delivery passage.

The valve plate 31 is fixed to the valve cover. The valve plate 31 includes: an arc-shaped suction port that communicates with the suction passage; and an arc-shaped delivery port that communicates with the delivery passage. The suction port and the delivery port are located on the same circumference about the rotating shaft 21.

The cylinder block 32 is fixed to the rotating shaft 21, and rotates together with the rotating shaft 21 while sliding on the valve plate 31. The cylinder block 32 includes cylinder bores. Some of the cylinder bores communicate with the suction port, and some of the other cylinder bores communicate with the delivery port.

Pistons 33 are received in the respective cylinder bores of the cylinder block 32. Shoes 34 are mounted to the heads of the respective pistons 33. In the present embodiment, the shoes 34 slide on a shoe plate 35 fixed to the swash plate 36. Alternatively, the shoes 34 may directly slide on the swash plate 36.

The electric motor 6 includes: an output shaft 61 extending in the horizontal direction; and a motor casing 62, which supports the output shaft 61 via bearings such that the output shaft 61 is rotatable. The motor casing 62 is a hollow casing, and a rotor and a stator are accommodated in the motor casing 62. The rotor is fixed to the output shaft 61, and the stator is fixed to the motor casing 62.

In the present embodiment, the rotating shaft 21 of the hydraulic pump 2 and the output shaft 61 of the electric motor 6 are coupled to each other by a tubular coupling 4. The inner peripheral surface of the coupling 4 includes a spline-shaped toothed surface, and each of the outer peripheral surface of the rotating shaft 21 and the outer peripheral surface of the output shaft 61 includes a spline-shaped toothed surface. These toothed surfaces mesh with each other.

However, the rotating shaft 21 and the output shaft 61 need not be coupled to each other by the coupling 4. For example, an end portion of one of the rotating shaft 21 or the output shaft 61 may be a hollow end portion; the one of the rotating shaft 21 or the output shaft 61 may receive therein the other; and a spline-shaped toothed surface of the rotating shaft 21 and a spline-shaped toothed surface of the output shaft 61 may directly mesh with each other. Alternatively, the rotating shaft 21 and the output shaft 61 may be coupled to each other via gears that mesh with each other, the gears being fixed to the rotating shaft 21 and the output shaft 61, respectively.

The connecting structure 5 is located between the pump casing 22 and the motor casing 62, and connects the pump casing 22 and the motor casing 62 to each other. In the present embodiment, the connecting structure 5 is a tubular structure that extends in the axial direction of the rotating shaft 21 and the output shaft 61, i.e., in the horizontal direction. The rotating shaft 21 and the output shaft 61 are accommodated in the connecting structure 5.

In the present embodiment, the pump casing 22 is fixed to the machine 9, and the connecting structure 5 and the electric motor 6 are positioned in the air to form a cantilever structure whose supporting point is the pump casing 22. An end of the motor casing 62 on the opposite side of the motor casing 62 from the connecting structure 5 is supported by the machine 9 via an elastic body 7. That is, the elastic body 7 is joined to the machine 9 and the end of the motor casing 62.

For example, in a case where the pressure source unit 1 is located within a room in the machine 9, the motor casing 62 may be supported by the surface of the floor of the room via the elastic body 7, or may be supported by the surface of a lateral wall of the room via the elastic body 7. The elastic body 7 may be, for example, a rubber block.

However, the elastic body 7 need not be joined to the end of the motor casing 62, but may be located between the motor casing 62 and the machine 9 such that the elastic body 7 is in surface contact with the bottom surface of the motor casing 62. In this case, the elastic body 7 may be, for example, a compression coil spring or a plate spring.

As described above, in the pressure source unit 1 of the present embodiment, since the motor casing 62 is supported by the machine 9 via the elastic body 7, vibration of the electric motor 6 can be suppressed. In other words, vibration of the electric motor 6 is absorbed by the elastic body 7.

Variations

The present disclosure is not limited to the above-described embodiment. Various modifications can be made without departing from the scope of the present disclosure.

For example, the hydraulic pump 2 may be a tandem pump or parallel pump that includes two piston pump structures, each piston pump structure including the valve plate 31, the cylinder block 32, the pistons 33, the shoes 34, and the swash plate 36. In a case where the hydraulic pump 2 is a tandem pump or parallel pump, by fixing the pump casing 22 of the relatively large-weight hydraulic pump 2 to the machine 9, the influence of the vibration is reduced.

Alternatively, as in a hydraulic system 1A of FIG. 2 showing a variation, not the pump casing 22 of the hydraulic pump 2, but the connecting structure 5 may be fixed to the machine 9. In FIG. 2, a stand 51, which extends downward from the connecting structure 5, is integrated with the connecting structure 5, and an elastic body 55 is located between the stand 51 and the machine 9. That is, the connecting structure 5 is fixed to the machine 9 via the stand 51 and the elastic body 55. The elastic body 55 may be, for example, a rubber block. In a case where the connecting structure 5 is fixed to the machine 9 in such a manner, since the length from the fixing position to the end of the electric motor 6 is reduced compared to a case where the pump casing 22 is fixed to the machine 9, the influence of the vibration is reduced.

In a case where the connecting structure 5 is fixed to the machine 9, desirably, an end of the pump casing 22 on the opposite side of the pump casing 22 from the connecting structure 5 is also supported by the machine 9 via an elastic body 8. The elastic body 8 may be, for example, a rubber block.

For example, the elastic body 8 is joined to the machine 9 and the end of the pump casing 22. However, the elastic body 8 need not be joined to the end of the pump casing 22, but may be located between the pump casing 22 and the machine 9 such that the elastic body 8 is in surface contact with the bottom surface of the pump casing 22. In this case, the elastic body 8 may be, for example, a compression coil spring or a plate spring.

According to the configuration shown in FIG. 2, vibration of the hydraulic pump 2, the vibration occurring in a case where the connecting structure 5 is fixed to the machine 9, can be suppressed.

Summary

The present disclosure provides, as a first mode, a pressure source unit installed on a machine, the pressure source unit including: a hydraulic pump including a rotating shaft and a pump casing; an electric motor including an output shaft and a motor casing, the output shaft being coupled to the rotating shaft; and a connecting structure that is located between the pump casing and the motor casing and that connects the pump casing and the motor casing to each other. The pump casing or the connecting structure is fixed to the machine. The motor casing is supported by the machine via an elastic body.

According to the above configuration, since the motor casing is supported by the machine via the elastic body, vibration of the electric motor can be suppressed. Particularly in a case where the hydraulic pump is a tandem pump or a parallel pump, by fixing the pump casing of the relatively large-weight hydraulic pump to the machine, the influence of the vibration is reduced. Alternatively, in a case where the connecting structure is fixed to the machine, since the length from the fixing position to an end of the electric motor is reduced compared to a case where the pump casing is fixed to the machine, the influence of the vibration is reduced.

As a second mode, in the first mode, the connecting structure may be fixed to the machine, and the pump casing may be supported by the machine via an elastic body. According to this configuration, vibration of the hydraulic pump, the vibration occurring in a case where the connecting structure is fixed to the machine, can be suppressed.

As a third mode, in the first or second mode, for example, the connecting structure may be a tubular structure that accommodates therein the rotating shaft and the output shaft.