JP2551258B2 - Swash plate type 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 an improvement of a swash plate type variable displacement compressor equipped with a double-headed piston.

[0002]

2. Description of the Related Art A swash plate type variable displacement compressor suitable for air conditioning of a vehicle is disclosed, for example, in JP-A-63-147977.
The compressor of this type shown in FIG. 3 has a double-headed piston 53 accommodated in a plurality of bores 52 formed in a cylinder block 51, and a rotary shaft on an axis parallel to the bores 52. 54 is provided, and a sleeve 55 is slidably fitted on the rotary shaft 54. A swash plate 57 whose peripheral portion engages with the double-headed piston 53 via the shoe 56 is fitted to the spherical support portion 55a of the sleeve 55 by the matching spherical surface portion 57a, and is stretched in front of the swash plate 57. A guide pin 58 is attached to the connecting portion 57b,
This is guided by the long hole 54b formed in the front shaft portion 54a of the rotary shaft 54, so that the swash plate 57 can be tilted as the sleeve 55 slides, and the tilting center is the double-headed piston 53. The top dead center position on the rear side is set to be unchanged.

The compression reaction force of the double-headed piston 53 always acts as a moment M in a direction to reduce the tilt angle of the swash plate 57, which urges the plunger 60 to the right in the drawing through the sleeve 55, while the plunger 60 is also moved to the right. 60
Is also urged to the left in the drawing by the motive pressure supplied to the control pressure chamber 59, and therefore, the inclination angle of the swash plate 57, that is, the discharge capacity of the compressor is determined by the balance of these opposing urging forces. Reference numeral 70 is a control valve for selectively adjusting the driving pressure supplied to the control pressure chamber 59. The detection pressure chamber of the control valve 70 is communicated with the swash plate chamber 61 via the pressure detection conduit a,
The suction pressure is immediately introduced as the detection pressure. Then, according to the detected pressure, the discharge pressure from the discharge chamber 62 via the high pressure pipe c is supplied as the activating pressure to the control pressure chamber 59 via the supply pipe b, or the pressure inside the control pressure chamber 59 is changed to the low pressure pipe. It escapes via the path d and the activation pressure is reduced accordingly.

[0004]

By the way, in the variable displacement type compressor as described above, the plunger 60 as a variable mechanism having a driving member substantially in the center of the cylinder block 51 and the rear housing 50 reciprocates in the front-rear direction. It is arranged freely. Therefore, a sufficient sealing area cannot be secured in the peripheral portion of the plunger 60. Therefore, the high-pressure compressed gas from the bore 52 leaks from between the cylinder block 51 and the valve plate 63 to the low-pressure inner peripheral portion, and the compression efficiency decreases.

The present invention has been made in view of the above circumstances, and it is a technical subject to be solved that the airtightness between the cylinder block and the valve plate in the peripheral portion of the driving member is enhanced to obtain high compression efficiency. Is.

[0006]

In order to solve the above-mentioned problems, the present invention closes a cylinder block accommodating a double-headed piston in a plurality of bores and front and rear end surfaces of the cylinder block through valve plates. A front and rear housing having a suction chamber and a discharge chamber which are provided in the end face on the valve plate side,
A rotary shaft disposed on an axis parallel to the bore, a sleeve slidably fitted to the rotary shaft, and a guide pin fitted into an elongated hole formed in the rotary shaft, The swash plate is rotatably supported by the sleeve so that the rear-side top dead center of the engaged double-headed piston does not change, and the driving member that changes the swash plate tilt angle by axial displacement of the sleeve. In the swash plate type variable displacement compressor, a spacer is arranged in the suction chamber of the rear housing, and the spacer is
A cylindrical base portion, a plurality of blades extending radially from the base portion and held on the inner wall surface of the suction chamber, and a front end surface extending forward from the base portion, the front end surface of which is a rear portion at an outer peripheral portion of the drive member. Side of the valve plate, which is capable of pressurizing, presses the valve plate by elastic deformation reaction force of the wing piece based on the interference provided between the valve plate and the closed end face of the rear housing. It is characterized in that the plate is pressed.

[0007]

In the compressor according to the present invention, since the pressing portion of the spacer arranged in the suction chamber presses the valve plate at the outer peripheral portion of the actuating member by the elastic deformation reaction force of the blade piece, It is possible to reliably prevent the high-pressure compressed gas from leaking to the low-pressure inner peripheral portion between the cylinder block and the valve plate.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a swash plate type variable displacement compressor according to the present embodiment. The front and rear end surfaces of a cylinder block 1 having a swash plate chamber 1a formed in the center thereof have front housings 2 through valve plates 15 and 16, respectively. The rear housing 3 is fixedly joined and closed. A plurality of sets of bores 1b and 1c are formed in the cylinder block 1 at opposing positions on the front side and the rear side of the swash plate chamber 1a, and a double-headed piston 10 is reciprocally housed in each of the bores 1b and 1c. . A rotation shaft 4 is rotatably supported by the front housing 2 and the cylinder block 1 on an axis parallel to the bores 1b and 1c.
The rear end of the rotary shaft 4 is connected and fixed coaxially with the rear shaft portion 4b through a connecting body 5 having an elongated hole 5a. A sleeve 7 is slidably fitted on the rear shaft portion 4b. A spring 8a is inserted in a gap between the rear shaft portion 4b and the sleeve 7, one end of the spring 8a is the connecting body 5, and the other end is the sleeve 7.
Is biased in the opposite direction. The sleeve 7 is inserted into a sleeve 6a having openings at both ends, and the sleeve 6a is attached to the cylinder block 1
It is slidably held in the rear sliding hole 1d. Sleeve 6
The sleeve 7 a is supported by the thrust bearing 13 and the radial bearing 14. At the center of the rear part of the cylinder block 1, a sleeve tube 6a and a plunger 6 to be described later are provided.
A central hole 1e through which b is inserted is formed.

A pair of support shafts 7a are provided in a radial direction at the base of the sleeve 7 located in the swash plate chamber 1a, and a swash plate 9 is tiltably supported with the support shafts 7a as pivots. Swash plate 9
Engages with the double-headed piston 10 via shoes 11, 12. A guide pin 9b is fitted to the central top of a bridge 9a having two pairs of legs extending from the front of the swash plate 9 so as to project in parallel with the support shaft 7a.
A rotor 9c is attached to the. The bridge 9a is inserted in the central gap (not shown) of the connecting body 5,
The rotor 9c is guided in the elongated hole 5a of the connecting body 5. Then, based on the axial displacement of the sleeve 7 cooperating with the sleeve 6a, the guide pin 9b is guided to the elongated hole 5a, whereby the tilt angle of the swash plate 12 changes, and the tilt center is the rear side of the double-headed piston 10. The top dead center is set to be unchanged.

Valve plates 15 and 16 are interposed between the cylinder block 1 and the front and rear housings 2 and 3, respectively.
In the front and rear housings 2 and 3, there are suction chambers 17,
18 and discharge chambers 19 and 20 are formed, and each discharge chamber 19 and 20 is connected to an external cooling circuit via a discharge port 21. Swash plate chamber 1 via front suction passage 22
The front suction chamber 17 communicating with a communicates with the front compression chamber Pf via the suction valve mechanism 23 provided on the valve plate 15, and the front discharge chamber 19 also communicates with the front compression chamber Pf via the discharge valve mechanism 24. It is in communication. On the other hand, the rear suction chamber 1 communicating with the swash plate chamber 1a via the rear suction passage 25
8 also communicates with the rear compression chamber Pr via a similar suction valve mechanism 26 provided on the valve plate 16, and the rear discharge chamber 20 also communicates with the rear compression chamber Pr via a discharge valve mechanism 27.

A plunger 6 is provided on the rear side of the rear suction chamber 18.
The b is fitted to the sleeve tube 6a so as to be slidable in the axial direction, and a control pressure chamber 18a is formed between the plunger 6b and the rear housing 3. In addition,
The plunger 6b and the sleeve tube 6a constitute a driving member according to the present invention. The plunger 6b has a large-diameter pressure receiving portion 62 at its rear end, and the outer peripheral surface of the pressure receiving portion 62 has a control pressure chamber 18a.
It is slidably held on the inner peripheral surface of the. Plunger 6b
A recess 63 is formed in the center of the rear end face, and the bottom of the recess 63 is biased toward the sleeve 6a by one end of the spring 8b, and the other end of the spring 8b is locked to the rear housing 3.

Rear suction chamber 1 divided by a plunger 6b
8 is provided with a ring-shaped spacer 31 through which the shaft cylinder portion 61 of the plunger 6b passes. As shown in the perspective view of FIG. 2, the spacer 31 has a thick-walled tubular base portion 32 and five thin-walled portions radially extending integrally from the outer peripheral surface of the base portion 32 and arranged at equal intervals in the circumferential direction. A plate-shaped wing 33 and a base 32
At the position where each wing piece 33 is formed, it is composed of the base portion 32 and five pressing portions 34 that extend in the same thickness as the front portion. Each wing piece 33 of the spacer 31 is fitted and held between a step portion 35 formed on the inner wall surface of the rear suction chamber 18 and five holding pieces 36 projecting from the inner wall surface in the centripetal direction. There is. The front end surface of each pressing portion 34 of the spacer 31 is in contact with the retainer 28 constituting the discharge valve mechanism. The front end surface of each pressing portion 34 faces the end surface of the cylinder block 1 between each rear bore 1c and the center hole 1e.
The press contact portion 34 of the spacer 31 is provided with an interference with the closed end surface A of the rear housing 3. Therefore, each wing piece 33 is held in a state of being elastically deformed.
Further, in the maximum capacity state of the compressor, the pressure receiving portion 62 of the plunger 6b abuts against the rear end surface of the base portion 32 of the spacer 31 and presses it, so that it has a so-called maximum capacity positioning function of the compressor. In the state, the pressure receiving portion 62 is configured to be separated from the spacer 31.

An activating pressure controlled by a control valve mechanism (not shown) is supplied to the control pressure chamber 18a. In this way, the driving pressure supplied into the control pressure chamber 18a is transmitted to the swash plate 9 via the plunger 6b, the sleeve 6a and the sleeve 7, and this is in the direction in which the inclination angle of the swash plate 9 is always reduced by the compression reaction force. The tilt angle of the swash plate 9, that is, the discharge capacity of the compressor is determined by counteracting the acting moment M and balancing the forces of the two.

When the compressor constructed as described above is operated and the rotary shaft 4 rotates, the swash plate 9 rotates integrally with the rotary shaft 4 and oscillates, and the two heads are passed through the shoes 11 and 12. The piston 10 reciprocates in the bores 1b and 1c.
The return refrigerant gas introduced via the suction pipe enters the swash plate chamber 1a from the inlet portion as the double-headed piston 10 reciprocates,
It is guided to the front and rear suction chambers 17 and 18 through the front suction passage 22 and the rear suction passage 25, respectively.
From this, it is sucked into the compression chambers Pf, Pr on the front side and the rear side and subjected to a compression action. Then, the refrigerant gas discharged from both compression chambers to the discharge chambers 19 and 20 via the discharge valve mechanisms 24 and 27 is sent out to the external refrigerant gas circuit via the discharge passage.

In the compressor of this embodiment, the spacer 3
The front end surface of each pressing contact portion 34 of the No. 1 opposes the end surface of the cylinder block 1 between each rear side bore 1c and the central hole 1e, and is in contact with the retainer 28. Moreover, the pressing contact portion 34 has an elastic deformation reaction force of each wing piece 33 based on the interference provided between the pressing contact portion 34 and the closed end surface A of the rear housing 3, that is, a force that always urges the pressing contact portion 34 forward. Is working.
Therefore, each pressing portion 34 can always press the valve plate 16 against the end surface of the cylinder block 1 in an airtight manner. Further, in the maximum capacity state of the compressor with the plunger 6b moved forward, the pressure receiving portion 62 of the plunger 6b abuts against the rear end surface of the base portion 32 of the spacer 31 and presses it. Therefore, in the maximum capacity state of the compressor where the compression ratio becomes high and the pressure easily escapes from the bore 1c to the central hole 1e, the valve plate 16 is pushed by the pressing load of the plunger 6b in addition to the elastic deformation reaction force of each blade 33. The cylinder block 1 can be pressed in an airtight manner.

Therefore, in the compressor of this embodiment, the high discharge pressure from each bore 1c causes the cylinder block 1 and the valve plate 1 to be discharged.
It is possible to reliably prevent the leakage from the portion between 6 and 6 to the low pressure central hole 1e side, and it is possible to obtain high compression efficiency. Further, the valve plate 16 can be airtightly pressed against the cylinder block 1 by applying the pressing load of the plunger 6b in the maximum capacity state where the leakage of the pressure in the bore 1c is a particular problem.

[0017]

As described in detail above, according to the present invention,
The spacer press-contact portion airtightly presses the valve plate against the cylinder block at the outer peripheral portion of the actuating member, and ensures that the compressed gas from the bore leaks to the low pressure inner peripheral portion between the cylinder block and the valve plate. Since this can be prevented, high compression efficiency can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a compressor showing an embodiment of the present invention.

FIG. 2 is a perspective view showing a spacer of the compressor.

FIG. 3 is a sectional view showing a conventional compressor.

[Explanation of symbols]

1 is a cylinder block, 1b and 1c are bores, 2 and 3 are housings, 4 is a rotating shaft, 6a is a sleeve, 6b is a plunger, 7 is a sleeve, 9 is a swash plate, 10 is a double-headed piston, 1
Reference numerals 5 and 16 are valve plates, 17 and 18 are suction chambers, 31 is a spacer, 32 is a base portion, 33 is a wing piece, and 34 is a pressing portion.

Claims (1)

(57) [Claims] 1. A cylinder block in which a double-headed piston is housed in a plurality of bores, and front and rear end surfaces of the cylinder block are closed via valve plates, respectively, and a suction is provided in the end surface on the valve plate side. A front and rear housing having a chamber and a discharge chamber, a rotary shaft arranged on an axis parallel to the bore, a sleeve slidably fitted on the rotary shaft, and the rotary shaft. A swash plate pivotally supported by the sleeve so as to keep the rear top dead center of the engaging double-headed piston unchanged, comprising a guide pin fitted into the elongated hole;
In a swash plate type variable displacement compressor provided with an activating member that changes the swash plate inclination angle by axial displacement of the sleeve,
A spacer is disposed in the suction chamber of the rear housing, and the spacer has a cylindrical base portion, a plurality of wings extending radially from the base portion and held on the inner wall surface of the suction chamber, and a front portion from the base portion. And a front end surface of the pushing member which is capable of pressurizing the valve plate on the rear side at the outer peripheral portion of the activating member and which is provided between the pressing portion and the closed end surface of the rear housing. A swash plate type variable displacement compressor characterized in that the valve plate is pressed by an elastic deformation reaction force of the blade piece based on the tightened margin.