JPS6394086A - Guide mechanism for variable stroke swash plate type compressor piston support - Google Patents

Abstract

PURPOSE:To enhance durability of the captioned piston support, by providing a support pin to a piston support connected to a connecting rod and guiding the piston support by means of both a slide shoe provided to the support pin and a guide groove that is formed parallel to a driving shaft of a housing. CONSTITUTION:A piston support 21 is connected to one end of a connecting rod 32 the other end of which a piston 31 is installed to. A support pin 26 extending in the radial direction is installed to the lower end of the piston support 21, while a slide shoe 29 is installed to the tip end of the piston support 21 via a slide ball 27. A radial guide groove 28 is formed in the inner periphery of a front housing 1, while the slide shoe 29 is fitted into the guide groove 28. The guide shoe 29 reciprocates within the guide groove 28 under being prevented by the guide groove 28 from rotating around the axis of the piston support 21.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a refrigerant compressor for an automobile air conditioner, and in particular to a variable stroke swash plate compressor suitable for a piston support guide mechanism having excellent durability and a compact structure. Regarding machines.

[Conventional technology]

Conventional piston support guide mechanisms for variable stroke compressors are disclosed in Japanese Patent Application Laid-open No. 56-77578 and Japanese Patent Publication No. 1987-61-
25917, etc., (1) a method in which a semi-cylindrical guide and a bearing body slide in the shaft direction on a guide rod supported parallel to the drive shaft;
(2) It was based on a universal schwin assembly held in a ball bearing supported at one end of the arm.

[Problem that the invention seeks to solve]

In the above conventional technology, in the case of method (1), the sliding speed of the bearing body that slides the guide rod is high, and the rotational speed of the compressor is particularly high when used in car air conditioners etc.
At the same rotation speed, the sliding speed of the bearing body exceeds 8 m/s. Therefore, there were problems with the lubrication and durability of the sliding parts including the bearing body. In addition, in the case of method (2), the reaction force of the drive torque of the compressor acts on the arm that supports the ball bearing, so the arm lacks rigidity, and the structure is complex and the arm is not installed. Because of this, the outside diameter of the compressor became larger, and insufficient consideration was given to making the compressor smaller and lighter, which caused layout problems in mounting the compressor in the engine room of an automobile.

The purpose of the present invention is to eliminate the drawbacks of the piston support guide mechanism of the variable stroke compressor, provide excellent durability,
The objective is to provide a compact variable stroke compressor that is small, lightweight, and durable.

[Means for solving problems]

A feature of the present invention is that a support pin is fixed in the lower position of the piston support in the radial direction by press-fitting or plastic bonding, and the support pin has a slide ball and a pair of spherical parts facing the slide ball. A semi-cylindrical slide shoe is rotatably and slidably mounted. Further, the shoe reciprocates in an axial groove provided on the inner circumferential surface of the front housing, and restricts movement around the axis so that the piston support does not rotate around the main axis. By providing such a piston support guide mechanism, the above object is achieved.

[Effect]

With the piston support guide mechanism described above, the slide ball and the support pin are a sliding pair, but since the sliding distance of the slide ball is short, the sliding speed can be significantly reduced. Further, since the groove for guiding the slide shoe is formed on the inner circumference of the front housing, the rigidity of the groove is improved and the outer diameter of the compressor can be reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show the overall structure of a variable stroke swash plate compressor according to the present invention. Figure 1 shows swash plate 1
2 indicates the maximum tilt, that is, the maximum piston stroke. At one end of the cylindrical cylinder block 2, there is a front housing 1 that rotatably supports the main shaft 13 via a radial bearing 18 in the center! i! are placed and fixed to form a swash plate chamber 10. The cylinder block 2
A plurality of cylinders 33 are formed circumferentially around the main shaft and parallel to the axis of the main shaft 13 . The main shaft 13 is located approximately on the center line of the cylinder block 2 and is provided with radial bearings 18 and 19 provided at the center of the cylinder block 2 and the front housing 1.
The drive plate 14 is rotatably supported by the drive plate 14, and the drive plate 14 is fixed by press fitting, pins, plastic bonding, or the like. The drive plate 14 is provided with a cam groove 142, and a fulcrum pin 16, which is fitted into the swash plate lug 121 with a gap, is movably mounted in the groove. Further, the drive plate lug 141 provided with the cam 142 groove and the swash plate lug 121 are structured so that their sides come into contact with each other.

As a result, the rotation of the main shaft 13 causes the drive plate 1 to
4 rotates, the ears 141 on the drive plate 14
A rotational force is applied to the swash plate lug 121, causing the swash plate 12 to rotate. A sleeve 15 is incorporated into the main shaft 13 so as to be slidable in the axial direction with respect to the main shaft 13.
And what is the swash plate 12?

Swash plate 12 relative to sleeve 15 by pivot pin 17
is rotatably fastened around the pivot pin 17. Therefore, due to the rotation of the main shaft 13, the drive plate 14. The swash plate 12° and the sleeve 15 rotate together. A piston support 21 is fastened to the swash plate 12 via a bearing 23, and a spacer 221 and a stopper 22 fixed to the swash plate 12 allow the bearing 23 to
It is fixed to the hub portion 122 of the swash plate so as not to move in the direction of the rotation axis of the swash plate 12.

On the other hand, the piston support 21 is restricted from moving to the right in FIG. Movement to is also regulated. Further, a support pin 26 is fixed in the lower position of the piston support 21 in the radial direction by a method such as press-fitting or plastic coupling. A pair of semi-cylindrical slide shoes 29 are rotatably and slidably mounted. In addition, the slide shoe 29
The piston support 21 reciprocates in an axial groove 28 provided on the inner circumference of the front housing 1, and the piston support 21 moves toward the main shaft 1.
The movement around the axis is restricted so that it does not rotate around 3. The piston support 21 has balls 32 at both ends.
A plurality of connecting rods 32 having an angle of 1°322
One end is rotatably attached around the center of the ball 321, and the piston 31 is attached to the other end so as to be rotatable around the center of the ball 322. The plurality of pistons 31 are assembled into a plurality of cylinders 33 provided in the cylinder block 2. The piston 31 is fitted with piston rings 34,35. The cylinder block 2 also includes a suction valve plate 5. Cylinder head 4. Discharge valve plate 6. A gasket 7 and a rear cover 3 are arranged, and a drive plate 14. The swash plate 12 is fixed to the rear cover 3 with bolts 36, 37 etc. integrally with the front housing 1 arranged so as to surround the piston support 21 etc., and the front housing 1 and the cylinder block 2
O-ring 38. The rear cover 3, cylinder block 2, and gasket 7 are kept airtight by an O-ring 39. The cylinder head 4 is provided with a suction boat 401 and a discharge port 402 corresponding to each cylinder 33,
It communicates with a suction chamber 8 and a discharge chamber 9 provided in the rear cover 3, respectively. The rear cover 3 has an inlet 301 and an outlet (
(not shown), and a control valve 41 is provided in the suction passage 302 between the suction port 301 and the suction chamber 8 .

The upstream side of the control valve 41 and the swash plate chamber 10 in the front housing 1 are connected to the rear cover 3. Packing 7, discharge valve plate 6. Conduction holes 303, 703, 603° 403 and 503 provided at the center of the cylinder head 4 and suction valve plate 5, and a passage 131 provided at the center of the main shaft 13, connected to the passages 131 and connected to the drive plate 14 in the radial direction. Passage 143 to open
It is connected by Further, the downstream side of the control valve 41 communicates with the suction chamber 8 .

With the configuration described above, when the main shaft 13 of the compressor is driven by the engine (not shown), the drive plate 14. The swash plate 12 rotates, and the piston support 21 swings about the rotation axis of the main shaft 13. therefore,
The piston 31 reciprocates inside the cylinder and sucks gas,
Compress. Note that the maximum stroke position can be regulated by bringing the sleeve 15 into contact with the drive plate 14, and the minimum stroke position can be regulated by installing a stopper 131 in a groove provided in the main shaft 13 and applying the sleeve to this. This has been achieved by The cam Wt142 formed on the drive plate 14 is a closed curve such that the top dead center position of the piston 31 does not change even if the fulcrum pin 16 moves within the cam groove 142. The thrust force that acts on the main shaft 13 when compressing gas is transmitted by the thrust bearing 42 installed between the drive plate 14 and the front housing 1, and also by the main shaft 13.
The radial force acting on the front housing 1 and the cylinder block 2 are
and 18.

3 and 4 are partial views showing the guide mechanism of the piston support 21. FIG. While the main shaft 13 rotates once, the support pin 26, slide ball 27, and slide shoe 29 move into the groove 28 provided in the front housing 1.
It makes one round trip in the order of (,) → (b) → (c) → (b) → (a). In FIG. 3, when the distance between the main shaft 13 and the center of the groove is Ll, and the swash plate tilt angle is α, the sliding distance Ls of the slide shoe 29 in the axial direction is expressed by equation (1).

Ls= 2 Lstana −
(1) Furthermore, the distance LB of the slide ball 27 sliding on the support pin 26 at this time is expressed by equation (2).

La= LA (1/cosa-1)
-(2) If the rotation angle of the main shaft is θ, the sliding speeds of the slide shoe 29 and the slide ball 27 vs and vB
are respectively expressed by the following equations. In other words, vs= 2 (
11LztanCLcosO-(3)va=2ωLx(
1/cosα−1)cosθ・(4)θ=ω・
t...(5)
Here, ω is the rotational angular velocity of the main shaft.

Here, the ratio β of the sliding speeds of the slide ball 27 and the slide shoe 29 is 2 tanα, and when α=25″, β″:0.1.

Therefore, the sliding speed of the slide ball 27 is significantly lower than the sliding speed of the slide shoe 29.

Next, if the driving torque of the compressor is T, then the support pin 26, the slide ball 27, and the slide shoe 2
The reaction force F acting on 9 is F = T r / Li
−(7). Therefore, slide ball 2
The surface pressure pa of 7 is: Here, d The inner diameter of the Nislide ball B The axial width of the Nislide ball The surface pressure Ps of the slide shoe is Here, A The length of the Nislide shoe C The width of the Nisslide shoe It will be done. Therefore, when the ratio γ of the surface pressure of the slide ball 27 and the surface pressure of the slide shoe 29 is determined, it becomes the ratio of the pressure receiving area as shown by. Here, B<C and d<
From the relationship A (see FIG. 4), γ>1. on the other hand,
A and C cannot be made too large due to structural limitations, and in the present invention, γ≦3. Therefore,
1, γ≦3, and the surface pressure acting on the slide ball 27 is greater than the surface pressure on the slide shoe 29.

Looking at the p-iV value, which represents the sliding characteristics of the sliding part, from the above results, the P-V value of the slide ball 27 is greater than the P-v value of the slide shoe 29, with B.γ=0. lX
3=0.3 times. Therefore, the sliding characteristics of the slide ball 27 can be significantly improved.

As shown in FIGS. 1, 2, and 3, a guide groove 28 for the slide shoe 29 to reciprocate
is provided at the bottom of the front housing 1 and has a substantially arch shape.

Therefore, the rigidity against the reaction force expressed by the above equation (7) is sufficiently taken into consideration.

In the present invention, the gap between the guide groove 28 of the front housing and the slide shoe 29 is approximately 30 to 40 μm.

【Effect of the invention〕

As described above, according to the present invention, in the guide mechanism for piston support, the sliding characteristics can be improved and the rigidity of the guide groove can be strengthened, so that a compact and lightweight variable stroke swash plate compressor with excellent durability can be realized. Can be provided.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram of a variable stroke swash plate compressor showing an embodiment of the present invention, FIG. 2 is a sectional view taken along line 1-1 in FIG. 1, and FIG. 3 is a partial view showing a piston support guide mechanism. Fourth
The figure is a perspective view of the guide mechanism section. DESCRIPTION OF SYMBOLS 1... Front housing, 2... Cylinder block, 12... Swash plate, 13... Main shaft, 21... Piston support, 26... Support pin, 27... Slide ball, 28... ...Guide groove, 29...Guide shoe, 31...Piston, 32...Connecting rod, 33...Cylinder.

Claims (3)

[Claims] 1. a housing having a crank chamber, a suction space, and a discharge space therein; a drive shaft rotatably supported within the housing; a plurality of cylinders, a piston fitted into each cylinder reciprocably, and a swash plate rotatably mounted around an axis perpendicular to the drive shaft;
The piston includes a rod fixed to the piston, a piston support that supports each rod and performs a rocking motion corresponding to the inclination angle of the swash plate, and the swash plate corresponds to the inclination angle with respect to the drive shaft. In a variable stroke swash plate compressor that reciprocates the piston during a stroke, a guide pin is fixed to the piston support, and the guide pin includes a pair of semi-cylindrical slides having a slide ball and a spherical portion facing the slide ball. mating the shoe,
A guide mechanism for a variable stroke swash plate type compressor piston support, characterized in that the slide shoe is rotatably and slidably mounted in a guide groove formed parallel to the drive shaft. 2. Claim 1, characterized in that the guide groove is formed in the inner peripheral part of the housing, and the groove shape is cylindrical.
Guide mechanism for variable stroke swash plate type compressor piston support as described in . 3. The sliding gap between the guide groove and the guide shoe is δ
The variable stroke swash plate type compressor piston support guide mechanism according to claim 1, wherein 30 μm≦δ≦50 μm.