Compressor

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This application claims priority from Korean Patent Application No. 2005-81668 filed Sep. 2, 2005, incorporated herein by reference in its entirety.

The present invention relates to a compressor, and more particularly, to a compressor, which has ribs for directly supporting a part of a valve plate in a suction chamber of a housing, thereby preventing a noise caused by vibration of the valve plate during the strike of a suction reed valve.

2. Background Art

In general, a compressor constituting an air conditioning device of an automobile is a device for selectively receiving driving power from a power source by a restricting action of an electromagnetic clutch, compressing refrigerant gas by a straight reciprocating motion of pistons after absorbing the refrigerant gas from an evaporator, and discharging it toward a condenser. Such a compressor is classified into various kinds according to compression methods and structures, and out of the compressors of the various kinds, a variable capacity compressor, which can vary a compression volume, has been widely used.

Hereinafter, referring to FIGS. 1 and 2, a prior art variable capacity swash plate type compressor will be described as an example.

The variable capacity swash plate type compressor 1 includes: a cylinder block 10 having a plurality of cylinder bores 11 formed inside the cylinder block 10 axially along a concentric circle; a front housing 20 mounted at the front part of the cylinder block 10 and having a crank chamber 21 formed therein; a rear housing 30 mounted at the rear part of the cylinder block 10 and having a suction chamber 31 and a discharge chamber 32 formed therein; a plurality of pistons 40 reciprocatingly inserted into each of the cylinder bores 11 of the cylinder block 10 and having a bridge 41 at the rear end portion thereof; a driving shaft 50 having an end portion rotatably passing through the front housing 20 and the other end portion rotatably inserted and mounted into the center of the cylinder block 10; a rotor 60 combined to the driving shaft 50 inside the crank chamber 21 and rotating with the driving shaft 50; a swash plate 70 mounted on the circumference of the driving shaft 50 by slidably combining a sleeve 65, having an edge rotatably mounted to an insertion space of the piston bridge 41 by interposing a shoe 45 between the insertion space and the edge of the swash plate 70, and movably connected to a hinge arm 61 of the rotor 60 so as to be rotated together with the rotor 60 and adjust its inclination angle against the driving shaft 50; and a valve unit 80 mounted between the cylinder block 10 and the rear housing 30 to suck refrigerant from the suction chamber 31 into the cylinder bore 11 during a suction stroke and discharge compressed refrigerant from the cylinder bore 11 into the discharge chamber 32 during a compression stroke.

In addition, the inclination angle of the swash plate 70 against the driving shaft 50 can be adjusted according to a change in pressure inside the crank chamber 21 by a control valve 90 mounted in the rear housing 30.

Furthermore, the compression coil spring 55 interposed on the driving shaft 50 between the rotor 60 and the swash plate 70 elastically supports the sleeve 65, to which the swash plate 70 is rotatably combined, against the rotor 60, so that the swash plate 70 can be returned to its original position.

Moreover, the valve unit 80 includes: a valve plate 81 having a refrigerant suction hole 81b and a refrigerant discharge hole 81a; a suction reed valve 82 mounted at a side of the valve plate 81 for opening and closing the refrigerant suction hole 81b; and a discharge reed valve 83 mounted at the other side of the valve plate 81 for opening and closing the refrigerant discharge hole 81a.

Meanwhile, the rotor 60 has a slot 62 formed on the hinge arm 61 thereof, and a connection hinge arm 73 having a hinge pin 74 is formed on a hub 71 of the swash plate 70, which puts opposite the hinge arm 61 of the rotor 60. The connection hinge arm 73 protrudes toward both sides of the hinge arm 61 and is movably combined to the slot 62 of the hinge arm 61.

As described above, in the variable capacity swash plate type compressor 1, a plurality of the pistons 40 arranged along the concentric circle of the cylinder block 10 perform the and backward reciprocating motion in order by the rotation of the swash plate 70.

Here, during the suction stroke of the pistons 40, the suction reed valve 82 of the valve unit 80 is opened by a drop of pressure inside the cylinder bore 11, whereby the cylinder bore 11 and the suction chamber 31 are fluidically communicated with each other and the refrigerant is induced from the suction chamber 31 into the cylinder bore 11.

Additionally, during the compression stroke of the pistons 40, the discharge reed valve 83 of the valve unit 80 is opened while the refrigerant is compressed by a rise of pressure inside the cylinder bore 11, whereby the cylinder bore 11 and the discharge chamber 32 are fluidically communicated with each other and the compressed refrigerant is discharged from the cylinder bore 11 into the discharge chamber 32.

In addition, the swash plate 70 adjusts its inclination angle in correspondence to a difference between pressure inside the crank chamber 21 and suction pressure inside the cylinder bore 11, whereby a discharge volume of the compressor 1 is varied.

However, the suction reed valve 82 strikes a blow to the valve plate 81 while being closed to tightly seal the refrigerant suction hole 81b of the valve plate 81, but in this instance, the valve plate 81 is vibrated and so generates noise when the suction reed valve 82 strikes a blow to the valve plate 81.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made to solve the above disadvantages of the prior arts, and it is an object of the present invention to provide a compressor, which has a rib for directly supporting a part of a valve plate in a suction chamber of a housing, thereby preventing a noise due to shaking of the valve plate during the strike of a suction reed valve.

To accomplish the above objects, according to the present invention, there is provided a compressor including: front and rear housings; a cylinder block mounted between the front and rear housings and having a plurality of cylinder bores; a plurality of pistons mounted inside the cylinder bores and performing a reciprocating motion while cooperating with a rotating motion of a swash plate rotating together with a driving shaft; and a valve unit mounted between one of the front and rear housings, which has a suction chamber and a discharge chamber, and the cylinder block, the valve unit having a suction reed valve and a discharge reed valve mounted at both sides of a valve plate, wherein the suction chamber has support means for directly supporting a part of the valve plate at a position corresponding to each valve plate of the suction reed valve to prevent a noise caused by vibration of the valve plate during the strike of the suction reed valve.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawings, in which:

FIG. 1 is a sectional view of a prior art compressor;

FIG. 2 is a sectional view of a rear housing of FIG. 1, showing a state where a suction reed valve is located virtually;

FIG. 3 is a sectional view of a compressor according to the present invention;

FIG. 4 is an exploded perspective view of a valve unit in the compressor according to the present invention;

FIG. 5 is a sectional view of a rear housing of FIG. 3, showing a state where a suction reed valve is located virtually; and

FIG. 6 is a graph for comparing noise of the prior art compressor with noise of the compressor of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will be now made in detail to the preferred embodiment of the present invention with reference to the attached drawings.

FIG. 3 is a sectional view of a compressor according to the present invention, FIG. 4 is an exploded perspective view of a valve unit in the compressor according to the present invention, FIG. 5 is a sectional view of a rear housing of FIG. 3, showing a state where a suction reed valve is located virtually, and FIG. 6 is a graph for comparing noise of the prior art compressor with noise of the compressor of the present invention.

As shown in the drawings, the variable capacity swash plate type compressor 100 includes: a cylinder block 110 having a plurality of cylinder bores 11 axially formed on a concentric circle; a front housing 120 mounted on the front part of the cylinder block 110 and having a crank chamber 121 formed therein; and a rear housing 130 mounted on the rear part of the cylinder block 110 and having a suction chamber 131 and a discharge chamber 132 therein.

A plurality of pistons 140 having a bridge 141 at the rear end thereof are reciprocatingly inserted and mounted to each of the cylinder bores 111 of the cylinder block 110.

In addition, a driving shaft 150 has an end portion rotatably passing through the front housing 120 and the other end portion inserted into the center of the cylinder block 110 in such a way as to be rotatably supported.

Moreover, a rotor 160 is combined to the driving shaft 150 inside the crank chamber 121 to rotate together with the driving shaft 150.

Furthermore, a swash plate 170 is rotatably mounted on a sleeve 165 which is slidably combined to the driving shaft 150 inside the crank chamber 121, has an edge rotatably mounted to an insertion space of the piston bridge 141 by interposing a shoe 145 between the insertion space and the swash plate, and is movably connected to a hinge arm 161 of the rotor 160 so that the swash plate 170 adjusts its inclination angle against the driving shaft 150 while being rotated together with the rotor 160.

Here, the swash plate 170 includes a hub 171 rotatably combined to the sleeve 165, which is slidably combined to the driving shaft 150, via a hub pin 166, and a swash plate board 172 combined to the outer peripheral surface of the hub 171.

In addition, the rotor 160 has a slot 162 formed on the hinge arm 161 thereof, and a connection hinge arm 173 having a hinge pin 174 is formed on the hub 171 of the swash plate 170, which puts opposite the hinge arm 161 of the rotor 160. The connection hinge arm 173 protrudes toward both sides of the hinge arm 161 and is movably combined to the slot 162 of the hinge arm 161.

Therefore, during displacement of the inclination angle of the swash plate 170, the hinge pin 174 supports an inclination motion of the swash plate 170 while sliding along the slot 162.

Meanwhile, a control valve 190 is mounted in the rear housing 130 and operationally fluidically communicates the discharge chamber 132 and the crank chamber 121 with each other to vary a difference between refrigerant suction pressure inside the cylinder bore 111 and gas pressure inside the crank chamber 121, whereby the inclination angle of the swash plate 170 can be adjusted.

Moreover, a compression coil spring 155 is mounted on the driving shaft 150 between the rotor 160 and the swash plate 170 to return the swash plate 170 to the original position.

In addition, a valve unit 180 is mounted between the cylinder block 110 and the rear housing 130 to suck refrigerant from the suction chamber 131 into the cylinder bore 111 during a suction stroke and discharge compressed refrigerant from the cylinder bore 111 into the discharge chamber 132 during a compression stroke.

The valve unit 180 includes: a valve plate 181, and a suction reed valve 182 and a discharge reed valve 183 mounted at both sides of the valve plate 181.

Here, the suction reed valve 182 is mounted on the side facing the cylinder bores 111 of the valve plate 181, and the discharge reed valve 183 is mounted on the side facing the rear housing 130.

The valve plate 181 includes: a plurality of refrigerant discharge holes 181a formed at a predetermined radial distance from the center thereof to be fluidically communicated with the discharge chamber 132 of the rear housing 130; and refrigerant suction holes 181b of the same number as the refrigerant discharge holes 181a, the refrigerant suction holes 181b being formed at a radial distance larger than the distance of the refrigerant discharge holes 181a to be fluidically communicated with the suction chamber 131 of the rear housing 130.

Here, five refrigerant suction holes 181b and five refrigerant discharge holes 181a are formed in the drawing, but it would be appreciated that the number of the refrigerant suction holes and the refrigerant discharge holes can be increased or decreased according to the number of the cylinder bores 111 of the cylinder block 110.

In addition, the valve plate 181 has setting pins 181c protruding from both sides thereof to set the positions of the suction reed valve 182 and the discharge reed valve 183 when they are combined to the valve plate 181.

Moreover, the suction reed valve 182 and the discharge reed valve 183 respectively have reeds 182a and 183a, which have a fixed elasticity and can open and close the refrigerant suction holes 181b and the refrigerant discharge holes 181a according to bending and spreading of the reeds 182a and 183a.

The suction reed valve 182 and the discharge reed valve 183 respectively have setting holes 182b and 183b for setting the positions of the suction reed valve 182 and the discharge reed valve 183 while the setting holes 182b and 183b are fit to the setting pins 181c of the valve plate 181.

Moreover, the suction chamber 131 of the rear housing 130 has support means 135 for directly supporting a part of the valve plate 181 at a position corresponding to each reed 182a of the suction reed valve 182 to prevent noise caused by vibration of the valve plate 181 during a strike by the opening and closing actions of the suction reed valve 182.

The support means 135 is formed by extending ribs 136 at a side of the inner wall surface of the suction chamber 131.

Here, the ribs 136 are in close contact with the valve plate 181, and can be formed in various shapes within a range that the ribs 136 are not overlapped with the refrigerant suction hole 181b formed on the valve plate 181. In the present invention, a pair of ribs 136 are formed at positions corresponding to both sides of the upper end portion of each reed 182a.

In this instance, it is preferable that the ribs 136 extend toward the center of the refrigerant suction holes 181b formed on the valve plate 181.

Furthermore, it is preferable that an angle (θ) formed between the central lines of the ribs 136 satisfies the following formula, 80°≦θ≦100° in order not to obstruct suction of the refrigerant through the refrigerant suction hole 181b of the valve plate 181 and to effectively prevent vibration of the valve plate 181.

If the angle (θ) is out of the range of the above formula, the ribs 136 become too distant from each other or get too near to each other, and so, vibration/noise of the valve plate 181 cannot be effectively prevented.

Moreover, when a thickness of the rib 136 is t and a diameter of the refrigerant suction hole 181b is D, it is preferable that a formula t/D satisfies the following formula: 0.36 ≤ t D ≤ 0.40 .

In the same way, when the above formula is satisfied, vibration/noise of the valve plate 181 can be effectively prevented without obstruction of suction of the refrigerant. Otherwise, namely, if the thickness (t) of the rib 136 is too small, vibration/noise of the valve plate 181 cannot be effectively prevented since the rib 136 cannot effectively support the valve plate 181, but if the thickness (t) of the rib 136 is too large, weight and material costs of the compressor are increased.

In addition, when the shortest distance from the center of the refrigerant suction hole 181b to the rib 136 is L and a diameter of the refrigerant suction hole 181b is D, a formula L/D satisfies the following formula: 0.44 ≤ L D ≤ 0.51 .

If the above formula is not satisfied, namely, if the shortest distance (L) becomes shorter, the rib 136 obstructs suction of the refrigerant, but if the shortest distance (L) becomes longer, the rib 136 becomes distant from the refrigerant suction hole 181b, and so, vibration/noise of the valve plate 181 cannot be effectively prevented since the rib 136 cannot effectively support the valve plate 181.

Meanwhile, as another example of the support means 135, the suction chamber 131 of the rear housing 130 may have additional pin (not shown) for directly supporting the valve plate 181.

FIG. 6 is a graph for comparing noise of the prior art compressor with noise of the compressor of the present invention. In FIG. 6, a red line is a measured noise value while an air conditioner is in an ON-state, and a black line is a measured noise value while the air conditioner is in an OFF-state. As shown in FIG. 6, when the air conditioner is in the ON-state, during an initial operation of the compressor 100, namely, at a low hertz area (a dotted line part), in the prior art compressor which has no ribs 136, noise (dB) is greatly increased, but in the compressor according to the present invention, which has the ribs 136, noise (dB) is decreased enough to satisfy.

As described above, the compressor 100 according to the present invention has the ribs 136 for directly supporting a part of the valve plate 181 to the suction chamber 131 of the rear housing, and so, can prevent vibration and noise of the valve plate 181 since the ribs 136 are in close contact with the valve plate 181 even though the reeds 182a strike a blow to the valve plate 181 when the suction reed valve 182 is opened or closed.

In addition, the case where the structure that the ribs 136 for directly supporting the valve plate 181 to the suction chamber 131 to prevent vibration and noise of the valve plate 181 is applied to the variable capacity swash plate type compressor 100 is described in the present invention, but the present invention is not restricted to the above, and can be applied to compressors of various kinds, such as a fixed capacity swash plate type compressor, a motor driven compressor and others, in the same method and structure to obtain the same effects.

The present invention can prevent vibration and noise of the valve plate during the strike of the suction reed valve since the suction chamber of the rear housing has the ribs for directly supporting a part of the valve plate.