JPH0121355B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a variable capacity compressor, and particularly to an improvement of a variable angle swinging swash plate compressor which is particularly suitable for use in vehicle air conditioning.

BACKGROUND ART Conventionally, as a compressor for vehicle air conditioning, a suction chamber and a discharge chamber are selectively communicated with a crank chamber through appropriate control means, and the pressure in the crank chamber is controlled to create a pressure difference between the suction pressure and the suction pressure. A variable angle wobble plate type compressor is known from Japanese Patent Application Laid-open No. 158382/1982, which changes the wobble plate angle and therefore the discharge capacity. This compressor is equipped with a rotation prevention mechanism so that the wobble plate performs rocking motion without rotating integrally with the rotary drive plate. In this anti-rotation mechanism, a guide pin press-fitted into the cylinder block and crankcase parallel to the drive shaft slidably guides a ball guide held on a wobble plate. The ball guide is held via a pair of semi-cylindrical guide shoes that are slidably mounted to allow radial reciprocation within the wobble plate. This configuration is published in Japanese Patent Publication No. 56-77578.
This is more clearly disclosed in the publication No.

In this type of compressor, a crankcase and a head are connected at the front and back by clamping the cylinder block, and this combination consists of multiple units spaced apart in the circumferential direction and extending parallel to the drive shaft. They are fastened together with a through bolt. This form is not clearly defined in the former conventional example, but in the latter conventional example, flange portions are formed on the outer shells of the crankcase and the head, respectively, and the above-mentioned through bolts are inserted into these flange portions. Achieved closure. However, since the formation of such a bulging flange increases the size of the compressor, considering installation in a limited engine room, the arrangement of the through bolts is limited to the axial projected area of the crankcase and head. Of these, it is particularly advantageous to require the interstices of a plurality of bores. Of course, there is no need to exemplify the arrangement of the through-bolts between the bores, as they are often used in compressors equipped with conventional fixed swash plates.

Problems to be Solved by the Invention As shown in the conventional example, for example, in a variable angle swinging swash plate compressor having five bores, the above-mentioned through bolts are arranged evenly between each of the bores. However, one of the bore intervening portions is occupied by the above-mentioned wobble plate, that is, the guide pin responsible for preventing rotation of the rocking plate. Therefore, if an attempt is made to dispose the through bolt further outward to avoid interference with the guide pin, not only will this portion bulge, resulting in an increase in the size of the compressor, but the above-mentioned joint that sandwiches the cylinder block will There is also the disadvantage of making the means of sealing between the bodies difficult. In addition, since the guide pin in the conventional example is press-fitted into the cylinder block, the distance relative to the bore must be secured to take account of the deformation of the bore. Coupled with the fact that a somewhat larger diameter must be selected in order to sufficiently withstand the bending force that accompanies movement, the above-mentioned disadvantages of increased physique are exacerbated.

This invention provides a mechanism for preventing the rotation of the oscillating plate by disposing a through bolt within the axial projected area set to the minimum necessary without causing the above-mentioned combined body that sandwiches the cylinder block to bulge and deform. The problem it attempts to solve is to skillfully coexist.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention has one of the through bolts engaged with one corner of the rocking plate via a universal joint that fits therein, A configuration is adopted that inhibits the rotation of the rocking plate while simultaneously guiding its movement in the axial direction.

Function: Therefore, one of the through bolts takes over the function of the conventional guide pin, so the through bolt can be distributed almost evenly between each bore clamp without the difficulty in placement caused by installing the through bolt together with the guide pin. At the same time, the through bolt is inserted with a gap between each element of the joint body, so there is no adverse effect such as press-fit deformation, and the through bolt can be inserted by tightening the joint body together. Since a tensile force is applied to the bolts, there is a large resistance to bending, and it becomes possible to use a bolt having the minimum diameter that ensures the strength necessary for the above-mentioned co-tightening.

Embodiment Hereinafter, an embodiment in which the present invention is embodied in a variable capacity compressor of a variable angle swinging swash plate type used in a vehicle air conditioner will be described with reference to FIGS. 1 to 5.

As shown in FIG. 1, a head 3 is connected to the left end surface of the cylinder block 1 via a valve plate 2. An annular suction chamber S is formed inside the head 3, and an inlet port 3a is connected to the head 3. Connected to external cooling circuit. In addition, a discharge chamber D is located in the center of the head 3.
is formed, and is also connected to the cooling circuit through a discharge port (not shown).

A crankcase 4 is coupled to the right end face of the cylinder block 1, and a shaft support hole 1a penetrating through the center of the block 1 and a cylindrical boss portion 4a integrally formed at the center of the crankcase 4 have a A drive shaft 6 is rotatably supported by a pair of radial bearings 5. The head 3, valve plate 2, cylinder block 1, and crankcase 4 are fastened together by through bolts 21 arranged parallel to the drive shaft 6 between respective bores, which will be described later. The drive shaft 6 is rotated by the power of the engine via a belt, a pulley, and an electromagnetic clutch (not shown).
Note that the inner end surface of the boss portion 4a and the stepped portion 6 of the drive shaft 6
A thrust bearing 7 is interposed between the shaft and the shaft a. In addition, a shaft seal chamber 8 is provided in the boss portion 4a.
A passage 4 is provided and is transparent to the crankcase 4.
It communicates with the crank chamber C through b, and is lubricated.

The cylinder block 1 has five bores 1b (one shown in FIG. 1 and five shown in FIG. 2) extending parallel to the drive shaft 6.
These bores 1b are spaced apart from the axis of the drive shaft 6 at equal angles in the radial direction and are located on concentric circles. A piston 10 having a seal 9 is mounted in each bore 1b so as to be capable of reciprocating sliding movement. A rod 12 is connected to the rear surface of each piston 10 via a spherical joint 11, and the rear end of each rod 12 is connected via a spherical joint 14 to a rocking plate 13 received so as to surround the drive shaft 6. (the piston 10 and rod 12 are collectively referred to as a piston assembly).

The oscillating plate 13 is the supporting cylinder portion 1 of the rotary drive plate 15.
5a, and its position is regulated by a thrust washer 16 and a stop ring 17 provided at the tip of the cylindrical portion 15a, and a thrust bearing 18 is interposed between the rotary drive plate 15 and the front surface thereof. The above drive shaft 6
A drive pin 19 is provided protruding in the radial direction, and the rotary drive plate 15 is attached to the pin 19 in the inclined guide groove 1.
It is attached so as to be tiltable in the axial direction by a connecting pin 20 penetrating through 9a.

A sleeve 40 is disposed on the drive shaft 6 so as to be positioned inside the support cylinder portion 15a of the rotary drive plate 15 and slidable in the axial direction on the drive shaft 6.
is loosely fitted, and the support cylinder portion 15a is attached to the sleeve 40 so as to be tiltable about the engagement pin 41, so that the drive plate 15 can be tilted stably around the connection pin 20. It's becoming like that. Note that a recess 40a from which the connecting pin 19 protrudes is formed in a part of the sleeve 40.

The swing plate 13 is provided with a rotation prevention mechanism that engages with one corner of the swing plate 13 so as not to rotate together with the rotary drive plate 15. This anti-rotation mechanism is shown in Figure 3~
As illustrated in more detail in FIG. 5, a major feature of the present invention is that the through bolt 2
One of these is the heavy pressure on alternatives. That is, the through bolt 21a located at the bottom in the figure
A ball guide 22 formed in a spherical shape is slidably fitted on the top, and the ball guide 22 has a concave hemispherical surface 23a that matches the spherical surface, and the back surface 2
3b is held between a pair of guide shoes 23, 23 formed in a convex semi-cylindrical shape. The swing plate 13 is provided with a slot 13a cut out in the radial direction at the lower part in the figure, and the opposing surfaces 13b, 13b
Each of the guide shoes 23 is formed into a concave semi-cylindrical shape that fits with the back surface 23b of the guide shoe 23. Therefore, the pair of guide shoes 23, 23 are fitted into the slot 13a while holding the ball guide 22, and the swing plate 1 is inserted along the opposing surfaces 13b, 13b.
Relative movement is allowed between 3 and 3.

On the other hand, a suction hole 2a for introducing refrigerant gas from the suction chamber S to the compression chamber in the cylinder chamber 1b is provided through the valve plate 2, and a suction valve 24 is provided corresponding to the suction hole 2a. There is. Similarly, a discharge hole 2b for guiding the refrigerant gas compressed in the cylinder chamber 1b to the discharge chamber D is provided through the valve plate 2, and a discharge valve 25 and a valve holder 26 are attached to a caulking pin 27 in correspondence with the discharge hole 2b. It is attached by.

Next, the operation of the variable angle swinging swash plate compressor configured as described above will be explained.

In the compressor, when the drive shaft 6 is rotated by the power of the engine, the drive pin 19 and the connecting pin 2
The rotary drive plate 15 is rotated via the rotary drive plate 15, thereby causing the swing plate 13 to swing back and forth without rotating. When the rocking plate 13 is rocked, the rod 12
Each piston 10 is reciprocated within the bore 1b through the refrigerant gas, and the refrigerant gas sucked from the suction chamber S through the suction hole 2a is compressed in the compression chamber of the bore 1b, and then is force-fed to the discharge chamber D from the discharge hole 2b.

Therefore, control of the discharge capacity according to the cooling load is generally performed as follows. That is, during periods of high cooling load, since the crank chamber C is communicated with the suction chamber S through a passage and control means (not shown), the blow-by gas released into the crank chamber C is also led out to the suction chamber S. Pressure increase in the crank chamber C is suppressed. Therefore, the pressure difference between the suction pressure and the crank chamber pressure (pressure acting on the back surface of the piston 10) is small, the rocking plate 13 maintains a deep slope as shown in the figure, and a large discharge capacity can be obtained by increasing the piston stroke. .

On the other hand, when the suction pressure decreases to a predetermined value due to a decrease in the cooling load, the control means reduces the cross-sectional area of the passage connecting the crank chamber C and the suction chamber S, and By appropriately opening the passage connecting the two, the crank chamber pressure is increased and the pressure difference between the crank chamber pressure and the suction pressure is increased. That is, the pressure acting on the back surface of the piston 10 is increased, thereby reducing the inclination of the rocking plate 13 and the piston stroke, thereby preventing a drop in suction pressure and at the same time reducing the capacity.

With the movement of the rocking plate 13 described above, the ball guide 22 slides on the through bolt 21a, and the guide shoes 23, 23, which clamp the ball guide 22, engage the ball guide 22 with their concave hemispherical surfaces 23a, 23a. Ball guide 2
At the same time, the rear surfaces 23b, 23b formed in a convex semi-cylindrical shape relatively slide along the opposing surfaces 13b, 13b of the corresponding slot 13a, thereby facilitating the smooth movement of the rocking plate 13. and rotation prevention is achieved.

In addition, in the above-mentioned embodiment, the through bolts 21, 21
A is screwed into the head 3, but if you reverse the head and tail and screw it into the crankcase 4, you can attach the rotational drive member, piston assembly, etc. to the cylinder block in advance, and then install the crankcase. Because it can be crowned and fastened,
Assembly work can be facilitated.

Furthermore, the above-mentioned mechanism for preventing rotation of the rocking plate is not limited to the ball guide and guide shoe fitted into the through bolt, but also includes a ball guide and a guide shoe fitted with the through bolt to smoothly guide the movement of the rocking plate. Of course, any universal joint may be used as long as it includes other means capable of inhibiting the rotation.

Effects of the Invention The variable displacement compressor according to the present invention has the following excellent effects due to the configuration described in the claims.

(1) There is no need to separately install a guide pin to prevent the rocking plate from rotating, and there is no bulge in the assembly including the cylinder block, which reduces the number of parts and downsizes the compressor. It's advantageous.

(2) Since the cylinder block does not have a press-fit like conventional guide pins, problems such as bore deformation do not occur, and the guide pin does not wobble due to loose interference and axial force. I don't feel sad.

(3) The through bolts, which are responsible for preventing the rotation of the rocking plate, are subjected to tensile force due to the joint tightening of the joints, so they exhibit strong resistance to the bending force that accompanies the movement of the rocking plate. A small diameter one can be used.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional front view showing an embodiment of a variable capacity compressor according to the present invention, and FIG.
3 is an enlarged side view showing the rotation prevention mechanism of the rocking plate, FIG. 4 is a plan view taken along the - line in FIG. 3, and FIG. 5 is a front view taken along the - line in FIG. be. 1...Cylinder block, 3...Head, 4...
... Crank case, 6 ... Drive shaft, 13 ... Rocking plate, 15 ... Rotating drive plate, 21, 21a ... Through bolt, 22 ... Ball guide, 23 ... Guide shoe.

Claims (1)

[Claims] 1. A cylinder block having a plurality of bores in the radial direction, a crankcase and a head connected to the front and rear parts of the cylinder block, a drive shaft supported by the cylinder block and crankcase, and a rotating shaft connected to the drive shaft. A variable capacity variable capacity comprising a drive plate, a rocking plate, a piston assembly, and a through bolt disposed in parallel with the drive shaft between each of the bores for fastening the crankcase, cylinder block, and head together. In the compressor, one of the through-bolts engages with one corner of the rocking plate through a universal joint fitted thereto, thereby inhibiting rotation of the rocking plate and at the same time preventing movement in the axial direction. A variable capacity compressor characterized in that it is configured to guide.