JPH0726627B2 - Variable capacity compressor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable capacity compressor suitable for use as, for example, a refrigerant compressor of an automobile air conditioner, and more particularly to a variable capacity compressor characterized by a sealing device for sealing an end face of a housing. Type compressor.

[0002]

2. Description of the Related Art In a vane type variable displacement compressor that employs a so-called "suction gas bypass system", a suctioned fluid (for example, a refrigerant) is compressed to some extent,
The discharge capacity of the compressor is changed (decreased) by discharging from the working chamber of the cylinder to the suction side through the bypass valve. However, by adjusting the opening degree of the bypass valve, the bypass amount, and accordingly the discharge amount. In order to change the capacity, a signal pressure intermediate between the discharge pressure (high pressure) and the suction pressure (low pressure) is created and supplied to the bypass valve. In that case, the passage for guiding the intermediate pressure (signal pressure) to the bypass valve is formed as a groove including a slit provided in the gasket on the mating surface (sealing surface) between the front housing and the front cover fastened thereto. Is convenient.

11 and 12 show an example of such a conventional technique. FIG. 11 shows a vane type variable displacement refrigerant compressor in which a front cover 12 is removed from a front housing (not shown). FIG. 12 is a side view showing the inner surface side, and FIG. 12 shows between the mating surface (sealing surface) 14 that is fastened to the front housing of the front cover 12 and the mating surface (sealing surface) on the front housing side. Loop gasket 16 to prevent the fluid from leaking through those gaps when sandwiched.
It is a top view which removes and shows these from the sealing surface.

As shown in FIG. 11, the sealing surface 14 of the front cover 12 is formed with a series of grooves 20 which are a part of the intermediate pressure introducing passage 18 extending over a substantially half circumference. The slit 16 is also provided with some slits 22 in series. The intermediate pressure introducing passage 18 is formed by these grooves 20 and slits 22, but it goes without saying that corresponding grooves can be provided on the sealing surface of the front housing in some cases. The internal space of the front cover 12 serves as a suction chamber 24, and in the case of a refrigerant compressor used for an air conditioner, the refrigerant is filled with a refrigerant having a pressure slightly higher than the atmospheric pressure returning from an evaporator (not shown), and When 10 is driven, it is sucked into the working chamber and is compressed.

The plate-shaped loop-shaped gasket 16 is made of a single or laminated thin metal plate, rubber or a synthetic resin material, and in some cases, an inorganic material such as asbestos. 12 in FIG.
A series of ridges 26 as shown in -b-c-d-e are formed so that when the front cover 12 is fastened to the front side housing by several bolts passing through bolt holes 28, the gasket 16 is It is effective to prevent the refrigerant from leaking into the outside air from the groove 20 forming the suction chamber 24 and the intermediate pressure introducing passage 18 by being pressed against the sealing surface 14 of the front cover 12 and the surface pressure of the portion of the protrusion 26 becomes particularly high. To prevent it.

[0006]

In the variable displacement compressor 10 of the intake gas bypass type, which has been prototyped in the past, the pressure (low pressure) of the refrigerant in the suction chamber 24 is abnormally increased, or the compressor 10 There is a problem in that the temperature of the discharged refrigerant may rise abnormally, which reduces the operating performance of the compressor. As a result of the inventors pursuing the cause thereof, it has been found that this problem is caused by leakage of the intermediate pressure refrigerant from the groove 20 serving as the intermediate pressure introduction passage 18 to the inside suction chamber 24 side. .

Therefore, if internal leakage of intermediate pressure is prevented,
It was expected that the problems of low pressure rise and high discharge temperature as described above would be solved, but in an attempt, in the inner peripheral portion 30 of the gasket 16 between the intermediate pressure introduction passage 18 and the suction chamber 24,
If a ridge similar to the ridge 26 along the outer peripheral edge is provided,
It was also found that a new problem occurs that the refrigerant leaks from the intermediate pressure introducing passage 18 toward the outer peripheral edge. This new problem is that the intermediate pressure introducing passage 18 is provided near the chain line a-b.
The intermediate pressure, which is higher than the suction pressure of the suction chamber 24, is exerted by the groove 20 which is a part of the bolt 16, and the bolt is provided by providing an additional protrusion on the inner peripheral portion 30 of the gasket 16. Since the tightening force is distributed to both the projections substantially evenly, and the surface pressure of the projections 26 on the sealing surface 14 of the front cover 12 near the chain line a-b is reduced, the intermediate pressure introducing passage 18 is provided. High pressure refrigerant
Before leaking to the suction chamber 24 side where the pressure is higher than atmospheric pressure,
It is considered that this is because the air leaks toward the outer peripheral side toward the outside air having a low pressure.

The present invention recognizes the above-mentioned problems of the prior art and solves the problems of the prior art by taking effective measures against the cause found as described above. This is a problem to be solved by the invention.

[0009]

In order to solve the above-mentioned problems, a variable displacement compressor according to the present invention is provided with a housing having a cylinder space formed therein and a bearing for rotating in the cylinder space. A rotor, a vane supported by the rotor so as to slide on an inner wall surface of the cylinder space, a working chamber formed by the inner wall surface of the cylinder space and the vane for compressing a fluid, A front having a mounting seal surface formed on one side of the housing and a suction chamber having a mounting seal surface matching the sealing surface for sucking a fluid to be compressed into the working chamber of the cylinder space. A groove that is provided on either or both of the cover and the sealing surface and forms a part of an intermediate pressure introducing passage that supplies a signal pressure to a bypass valve that changes the discharge capacity. A gasket having a slit at a position corresponding to the groove of the sealing surface and being sandwiched and fastened between the sealing surfaces, wherein the gasket has a large surface in an area along an outer peripheral edge of the outside of the slit. A pressure is generated, and a surface pressure smaller than the large surface pressure of the area along the outer peripheral edge and larger than the other parts on the gasket is generated in the area along the inner peripheral edge of the inside of the slit. It is characterized by being.

[0010]

[Operation] When the rotor is rotationally driven by external power,
The working chamber formed by the inner wall surface of the cylinder space and the vane expands to suck the fluid from the suction chamber, and then compresses and discharges the fluid when contracting. The bypass valve changes the discharge capacity of the compressor by releasing the fluid in the middle of compression to the suction chamber, but the signal pressure for operating it bypasses through the intermediate pressure introduction passage of the seal surface that sandwiches the gasket. Supplied to the valve. The intermediate pressure introduction passage is formed by the groove on the sealing surface and the slit provided at the corresponding position on the gasket.There is a possibility that the fluid with high pressure introduced into this passage may leak not only to the outside but also to the suction chamber inside. is there. However, in the present invention, a large surface pressure is generated in the area along the outer peripheral edge of the slit provided in the gasket, and in the area along the inner peripheral edge of the inside of the slit, the large area of the area along the outer peripheral edge. Since the surface pressure is smaller than the surface pressure and larger than the other parts on the gasket, the large area of the surface pressure along the outer peripheral edge of the slit prevents the fluid from leaking to the outside. In addition, the internal leakage from the intermediate pressure introduction passage to the suction chamber is also prevented by the region along the inner peripheral edge of the slit that generates a surface pressure smaller than that.

In the present invention, since the order of the magnitude of the surface pressure generated in each region of the gasket is provided, the surface pressure is reduced over the entire surface of the gasket and the pressure difference from the intermediate pressure introducing passage is large. There is no fear of fluid leaking to the outside, and effective prevention of leakage from the intermediate pressure introduction passage to the internal suction chamber prevents excessive rises in suction pressure and discharge temperature. The performance of the machine is improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 3 to 5 show the structure of the main part of a variable capacity compressor 110 in which the present invention is implemented. In particular, in FIG. 3, which is a vertical sectional front view of the entire structure, 112 is a front cover, and its mounting seal surface 114
Is pressed against the sealing surface 134 of the front side housing 132 via the gasket 116, and the through bolt 1
36 and the like are integrally fastened. Front cover 1
The mounting seal surface 114 of 12 has an intermediate pressure introduction passage 1
The groove 120 that is a part of the
Is provided over approximately half the circumference.

FIG. 4 is a front cover 11 shown in FIG.
2 is removed and the compressor body side such as the side surface of the front side housing 132 is viewed, and the state where the gasket 116 is attached to the sealing surface 134 of the front side housing 132 is shown. The gasket 116 is provided with a slit 122 that substantially coincides with the groove 120 provided on the mounting seal surface 114 of the front cover 112, and constitutes an intermediate pressure introducing passage 118 together with the groove 120. The intermediate pressure introducing passage 118 is shown in detail in FIG. 5, which is a sectional view taken along line VV in FIG.
The pressure chamber 142 is connected to the pressure chamber 142, and the intermediate pressure refrigerant between the discharge pressure (high pressure) and the suction pressure (low pressure) is guided to the pressure chamber 142 as a signal pressure.

The bypass valve 140 has a piston-shaped valve element 146 which is slidably displaced in a cylinder chamber 144 formed integrally with the front side housing 132, and is formed on the valve element 146 as described above. Pressure chamber 142
The signal pressure is received from the intermediate pressure introduction passage 118, and the space below the valve body 146 communicates with the low pressure suction chamber 124. Further, the valve body 146 is provided with a compression spring 148.
The pressure chamber 142 is biased by the direction. On the wall surface of the cylinder chamber 144, a bypass inlet 150 (two in the illustrated example) that is opened and closed by a valve body 146,
The bypass outlet 15 which is also opened and closed by the valve body 146
2 is provided, and the bypass inlet 150 is opened to the working chamber side of the cylinder of the variable displacement compressor 110, and the bypass outlet 152 is opened to the suction chamber 124 side formed in the front cover 112. The bypass outlet 152 has a cover member 1 for suppressing pressure fluctuation.
54 are attached by bolts 156.

Returning to FIG. 3, the center housing (cylinder) 1 fastened to the front side housing 132 is shown.
A cylinder space 162 is formed in the rotor 60, and the rotor 16 integrated with the shaft 164 is formed at an eccentric position in the cylinder space 162.
6 is bearing. A number of vanes 168 are attached to the rotor 166 so that the vanes 168 can freely slide in and out, and the tips of the vanes 168 slide on the inner surface of the wall of the cylinder space 162, so that between the adjacent vanes 168, the rotor 166 rotates. A working chamber 170 having a variable volume is formed. The discharge chamber housing 1 is located above the center housing 160.
72 is attached and a discharge chamber 174 is formed therein. Reference numeral 176 represents a discharge valve.

In FIG. 3, 178 is a rear side housing which is fastened to the center housing (cylinder) 160, 180 is a rear cover which is fastened further outside the rear side housing 178 and forms an oil separation chamber 182 inside, 184 is a discharge chamber 174 and It is a discharge port that communicates with the oil separation chamber 182 and sends the compressed high-pressure refrigerant toward the condenser. Then, the front cover 112, the front side housing 132, the center housing 16
0, rear side housing 178, and rear cover 18
0 constitutes the outer shell of the variable displacement compressor 110 that is wholly integrated by being fastened by several through bolts 136. Of these, the front side housing 132, the center housing 160, and The rear side housing 178 integrally includes the cylinder space 16
In the present invention, these components are collectively referred to as a "housing" because they constitute the second component.

When the variable capacity compressor 110 is used as a refrigerant compressor of an air conditioner, low temperature and low pressure refrigerant gas returning from an evaporator (not shown) enters the suction chamber 124,
The air is sucked from the suction port 188 shown in FIG. 4 into the working chamber 170 formed between the plurality of vanes 168. Shaft 1
64 is driven to rotate the rotor 166 in the eccentric position, so that the working chamber 170 formed between the vanes 168.
After the volume expands and the refrigerant is sucked in as described above,
By being removed from the position of the inlet 188, it is sealed,
Next, the volume is reduced to compress the refrigerant and discharge the high-temperature, high-pressure refrigerant gas to the discharge chamber 174. The discharged high-pressure refrigerant gas is sent to a condenser (not shown) via the oil separation chamber 182 and the discharge port 184, cooled to become a liquid refrigerant, and circulates in the refrigeration cycle to transfer heat.

Until the discharge amount (flow rate) exceeds the target value, a high pressure close to the discharge pressure is supplied as a signal pressure to the pressure chamber 142 of the bypass valve 140 shown in FIG. 5 through the intermediate pressure introducing passage 118. , Thereby the piston-shaped valve body 14
Since 6 is pushed down against the compression spring 148 and blocks the communication between the bypass inlet 150 and the bypass outlet 152, the pressure in the working chamber 170 of the cylinder does not drop halfway. When the discharge amount of the variable displacement compressor 110 exceeds the target value, the intermediate pressure introduction passage 1
The pressure of 18 is reduced by the action of a pressure control valve (not shown) and approaches the pressure (low pressure) of the suction chamber 124. Therefore, the piston-shaped valve body 146 is pushed by the compression spring 148 and moves upward so as to reduce the pressure chamber 142,
Due to the communication between the bypass inlet 150 and the bypass outlet 152, a part of the refrigerant compressed in the working chamber 170 is discharged to the suction chamber 124 through the cover member 154 and discharged to the discharge chamber 174. The amount of refrigerant is reduced. In this way, the variable displacement compressor 110 can freely change the discharge capacity.

Next, the gasket 11 which is an essential part of the present invention.
A first embodiment of No. 6 will be described. Gasket 1 of the first embodiment
16 is shown in FIG. 1, and the II-II cross section in FIG. 1 is shown by (a) and (b) of FIG. Gasket 11
6 is made of one or a combination of one or a combination of thin metal plates, rubber or synthetic resin materials, and in some cases inorganic materials such as asbestos, as in the conventional case, or a combination thereof. Are provided in series over approximately half the circumference. In addition, the broken line a-b-
By forming a series of ridges 126 as shown in cd-e, the front cover 112 is fastened to the front side housing 132 by several bolts 136 (see FIG. 3) passing through the bolt holes 128. The sealing between the mounting seal surface 114 of the front cover 112 and the seal surface 134 of the front side housing 132 is substantially the same as the conventional example described with reference to FIG. is there.

The feature of the first embodiment is that, in addition to the protrusion 126 extending along the outer peripheral edge of the gasket 116, a special protrusion 186 is also formed on the inner peripheral portion 130 inside the slit 122 by a chain line f-.
It is provided like gh-i. The ridges 126 along the outer peripheral edge have the same height h ₁ over the entire circumference of the gasket 116 as shown in the cross section of FIG. 186
₂ is formed so low that its height h ₂ is about 60% of the height h ₁ of the protrusion 126 along the outer peripheral edge, as shown in the cross section in FIG.

Since the gasket 116 of the first embodiment is constructed in this way, it is attached to the mounting seal surface 114 of the front cover 112 and the front side housing 1.
When the through bolt 136 is tightened while being sandwiched between the mounting seal surface 134 of 32, the gasket 116.
Ridges 12 along the outer peripheral edge protruding the highest from the surface of the
6 is the mounting sealing surface 114 or 13 opposite to it
4, a local surface pressure is generated and the suction chamber 12
4 and the intermediate pressure introducing passage 118 can prevent the refrigerant from leaking to the outside. Through bolt 136
When tightened, the ridge 126 along the outer peripheral edge is further compressed,
Not only does the surface pressure increase to improve the sealing performance, but this time, the inner peripheral side protrusions 186 also come into contact with the opposing sealing surface, and are slightly smaller than the protrusions 126 along the outer peripheral edge, but the intermediate pressure is introduced. A sufficient amount of surface pressure is created for the purpose of an internal seal between the passage 118 and the suction chamber 124. In this way, simply tightening the through bolt 136
Inner and outer ridges 186 and 126 and mating sealing surface 114
Or 134, a surface pressure having a large or small difference is automatically given, and the refrigerant is not only directed to the outside but also to the suction chamber 12 inside.
There is no fear of leaking to 4. In addition, the inner ridge 1
Since the surface pressure generated at 86 is relatively small,
The surface pressure generated on the protrusions 126 along the outer peripheral edge is reduced by a small amount, and external leakage does not occur in place of preventing internal leakage.

FIG. 6 shows a second embodiment of the gasket 116 according to the present invention, and the plan view thereof is not much different from that of FIG. 1, so that it is omitted here to avoid duplication. The gasket 116 of the second embodiment has a cross-sectional shape that is bent and has a step to improve the sealing property. The corners 190 and 192 generated by the step are as if the ridges of the first embodiment are generated by tightening the gasket 116 of the second embodiment between the sealing surfaces 114 and 134 of the front cover 112 and the front side housing 132. 1
Similar to 26 and 186. That is, the surface pressure becomes higher in the corners 190 and 192 than in the other parts, thereby improving the sealing performance.

Then, in a portion along the outer peripheral edge, as shown in FIG.
When a step of only h ₃ is given as shown in (a), in the inner peripheral portion 130 inside the slit 122,
By giving the step h ₄ smaller than that,
For the same reason as described in the embodiment, it is possible to completely prevent the leakage of the refrigerant from the intermediate pressure introducing passage 118 to the outside, and also to sufficiently prevent the leakage to the inside (suction chamber 124). .

7 and 8 show a gasket 1 according to the present invention.
16 shows a third embodiment of the present invention, in which the width of the inner peripheral portion 130 of the gasket 116, which is the inside of the slit 122, is compared with the width of the outer peripheral portion, while the protrusions 126 are provided along the outer peripheral edge as in the conventional case. It is characterized by being extremely narrow. For example, when the width w _{1 of the} outer peripheral portion is several mm, the inner peripheral portion 1
The width w ₂ of 30 is about 1 mm. In FIG. 8, (a)
Shows a cross section of the outer peripheral portion of the gasket 116 having the protrusion 126, and (b) shows a cross section of the inner peripheral portion 130. When the width w ₂ of the inner peripheral portion 130 becomes smaller, the load bearing area becomes smaller. Therefore, even if the surface pressure of the inner peripheral portion 130 is not as great as the surface pressure of the ridge 126 along the outer peripheral edge, It is larger than the part without the line. Therefore,
This part is the slit 122 which is the intermediate pressure introducing passage 118.
To prevent the refrigerant from leaking into the suction chamber 124. The leakage of the refrigerant to the outside is completely prevented by the ridges 126 along the outer peripheral edge, and the action is the inner peripheral portion 13 having a narrow width.
The presence of 0 is not substantially weakened. Note that as the width of the inner peripheral portion 130 of the gasket 116 is reduced, the sealing surfaces 114, 13 of the front side housing 132 and the front cover 112 that come into contact with the inner peripheral portion 130 are narrowed.
It goes without saying that the width of 4 can be narrowed.

9 and 10 show a fourth embodiment of the present invention. In this embodiment, instead of using the conventional gasket 116, the mounting seal surface 114 of the front cover 112 or the front side housing is used. 132
The sealing surface 134 is modified with an improvement. Figure 9
As shown in FIG. 5, the groove 120 (the intermediate pressure introducing passage 11
8) has an inner peripheral portion 194 which is a land portion on the inner side of FIG.
The groove 196 as illustrated in FIG. The width and depth of the groove 196 are both 1 to 2 for example.
It is about mm. Although the cross-sectional shape of the groove 196 shown in FIG. 10 is a wedge shape, the shape is not necessarily limited to that. By providing the groove 196, the effective width of the inner peripheral portion 194 is narrowed, and the inner peripheral portion 194 and the gasket 16 in the mounting seal surface 114 are the same as in the third embodiment.
The contact surface pressure with is a little higher than other parts. Therefore, the leakage of the refrigerant from the intermediate pressure introducing passage 118 to the suction chamber 124 is prevented. Leakage from the intermediate pressure introduction passage 118 to the outside is completely prevented by the protrusions 26 along the outer peripheral edge which are also provided in the conventional gasket 16.

[0026]

By implementing the present invention, both external leakage and internal leakage of the compressed fluid in the variable displacement compressor can be reliably prevented. In particular, since internal leakage from the intermediate pressure introduction passage for the bypass valve to the suction chamber is prevented, it is possible to avoid an abnormal rise in suction pressure and discharge temperature, and improve the operating performance of the compressor.

[Brief description of drawings]

FIG. 1 is a plan view showing a gasket according to a first embodiment of the present invention.

2A and 2B are enlarged cross-sectional views of a II-II portion of FIG.

FIG. 3 is a vertical cross-sectional view showing the entire structure of a variable displacement compressor.

FIG. 4 is a side view showing a part of the variable displacement compressor of FIG. 3 as seen.

5 is a cross-sectional view showing a bypass valve of VV section in FIG.

6 (a) and 6 (b) are sectional views showing a part of a gasket according to a second embodiment of the present invention in an enlarged manner.

FIG. 7 is a plan view showing a gasket according to a third embodiment of the present invention.

8A and 8B are enlarged cross-sectional views taken along line VIII-VIII in FIG. 7.

FIG. 9 is a side view showing a variable capacity compressor according to a fourth embodiment of the present invention with a part thereof removed.

10 is a cross-sectional view showing a groove of an XX portion in FIG.

FIG. 11 is a side view showing a conventional variable displacement compressor with a part thereof removed.

12 is a cross-sectional view showing a gasket used in the variable displacement compressor of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Conventional variable capacity compressor 16 ... Conventional gasket 26 ... Projection along the outer peripheral edge 30 ... Inner peripheral portion 110 ... Variable capacity compressor 112 of the present invention 112 ... Front covers 114,134 ... Mounting seal surface 116 ... Gasket 118 ... Intermediate pressure introducing passage 120 ... Groove 122 ... Slit 124 ... Suction chamber 126 ... Projection 130 ... Inner peripheral portion 132 ... Front side housing 140 ... Bypass valve 162 ... Cylinder space 168 ... Vane 170 ... Working chamber 186 ... Inner periphery Side protrusions 188 ... Intake ports 190, 192 ... Corners

Claims (1)

[Claims] 1. A housing having a cylinder space formed therein, a rotor rotatably supported in the cylinder space, and a vane supported by the rotor so as to slide on an inner wall surface of the cylinder space. A working chamber formed by the inner wall surface of the cylinder space and the vane for compressing fluid, a mounting seal surface formed on one side of the housing, and a mounting seal surface matching the sealing surface. To a bypass valve that is provided on either or both of a front cover that internally forms a suction chamber for sucking the fluid to be compressed into the working chamber of the cylinder space and that changes the discharge capacity. A groove forming a part of the intermediate pressure introducing passage for supplying a signal pressure,
The gasket includes a gasket having a slit at a position corresponding to the groove of the sealing surface and sandwiched between the sealing surfaces and fastened, and the gasket has a large surface pressure in a region along an outer peripheral edge of the outside of the slit. And a surface pressure smaller than the large surface pressure of the area along the outer peripheral edge and larger than the other parts on the gasket are generated in the area along the inner peripheral edge of the inside of the slit. A variable capacity compressor characterized in that