JPS634029B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a swash plate compressor suitable for vehicle air conditioning, and more particularly to a swash plate compressor having a suction hole and a suction valve at the top of a piston.

In a swash plate compressor that is equipped with a suction hole and a suction valve at the top of the piston and is configured to suck refrigerant gas from the swash plate chamber into the cylinder bore, a rivet or the like is press-fitted into a blind hole drilled in the axial direction at the top of the piston. Since the suction valve is fixed by tightening, the air sealed in the cavity at the bottom of the hole may push out the rivet during operation of the compressor, or the rivet may rust due to the sealed air. There were other drawbacks.

An object of the present invention is to provide a swash plate compressor that can eliminate the above-mentioned conventional problems.

Embodiments of the present invention will be specifically described below based on the drawings. As shown in the figure, the opposite ends of the front and rear cylinder blocks 1 and 2 are connected to valve plates 3 and 4.
Through front and rear housing 5,6
is blocked by. front housing 5
A suction chamber 7 and a discharge chamber 8 are defined by a partition wall 9, and the suction chamber 7 is communicated with an external circuit via a suction port 10, and the discharge chamber 8 is communicated with an external circuit via a discharge port (not shown). There is. The rear housing 6 is formed with a bulge 6a that presses the discharge chamber 11 and the valve plate 4 against the rear end face of the cylinder block 2, and the rear discharge chamber 11 and the front discharge chamber 8 are arranged as follows.
As shown in FIG. 2, they are communicated by discharge passages 12, 13 extending through the valve plates 3, 4 and discharge passages 14, 15 extending through the cylinder blocks 1, 2.

A drive shaft 16 is inserted through the center of the cylinder blocks 1 and 2 and rotatably supported by a bearing 17, and one end of the drive shaft 16 extends through the suction chamber 7 of the front housing 5. It can be connected to an external drive source. A swash plate 1 , which is fixed to the drive shaft 16 at an angle, is provided in a swash plate chamber 18 formed at the opposing portion of the cylinder blocks 1 and 2 .
9 is rotatably housed, and this swash plate chamber 18
are a suction passage 20 bored in the front cylinder block 1 and a suction passage 2 penetrated in the valve plate 3.
It communicates with the suction chamber 7 via 1. Furthermore, both cylinder blocks 1 and 2 are provided with the drive shaft 1.
A suitable number of cylinder bores 22, 23 are bored in the cylinder bores 22, 23, which are arranged radially and parallel to each other, with the cylinder center 6 as the center. show 2
A double-headed piston 25 moored via a bearing device consisting of four bearings is fitted so as to be able to reciprocate and slide.

The piston 25 has at its top a suction hole 26 for introducing refrigerant gas from the swash plate chamber 18 into the cylinder bores 22, 23, and a suction valve 27 for opening and closing the suction hole 26. The rivet 2 is inserted into the mounting hole 28 drilled in the axial direction.
It is fixed by press fitting 9. Also,
A first communication hole 30 is bored in the axial direction in the piston 25 as a relief hole for opening the bottom cavity 28a of the mounting hole 28 to the outer surface of the piston.
communicates the hole bottom cavity 28a with a concave spherical surface portion 31 which is the engagement seating surface of the ball 24. Furthermore, a second communication hole 32 as a relief hole is bored in the piston 25 in the radial direction, and the second communication hole 32 communicates the hole bottom cavity 28a with the vicinity of the entrance of the suction hole 26. In addition, in the figure, 33 is the valve plate 3, 4.
34 is a discharge valve, and 35 is a valve holder.

This embodiment is configured as described above,
Therefore, when the compressor is operated, refrigerant gas flows from the suction chamber 7 through the suction hole 21 and the suction passage 20 into the swash plate chamber 18, and from there flows into the cylinder bores 22, 2 through the suction hole 26 of the piston 25.
3, the gas in the rear discharge chamber 11 is forced into the discharge chambers 8 and 11 through the discharge hole 33 by the compression action of the piston 25, and the gas in the rear discharge chamber 11 passes through the discharge hole 13 and the discharge passage 14 to the front. It merges with the gas in the discharge chamber 8 and flows out to the external circuit.

During operation of the compressor, during the suction stroke, the pressure near the inlet of the suction hole 26 temporarily decreases compared to other locations in the swash plate chamber 18 due to the gas suction action; )
Since the gap between the shoe 24 and the piston spherical portion 31 (and the gap between the shoe 24 and the swash plate 19) increases, a portion of the gas in the swash plate chamber 18 is transferred from the gap between the shoe 24 and the piston spherical portion 31 to the 1 communication hole 30
and the second through the hole bottom cavity 28a of the mounting hole 28.
It flows into the communication hole 32. That is, during operation, the above-mentioned gas flow occurs, resulting in the above-mentioned drawbacks of the prior art. Trouble caused by sealed air remaining in the hole bottom cavity 28a is eliminated, and
The lubricating effect of the oil in the gas flowing between the shoe 24 and the piston spherical portion 31 is enhanced, and wear and seizure thereof are prevented.

In addition, when only the first communication hole 30 is used as a relief hole for the bottom cavity 28a of the mounting hole 28, the mounting hole 2
Not only can it prevent air from remaining in 8.
The hole bottom cavity 28a and the first communication hole 30 function as oil reservoirs, which can be expected to have a lubricating effect on the spherical surface, and if only the second communication hole 32 is used, the residual air in the mounting hole 28 It is possible to prevent this.

Next, another embodiment of the present invention will be described based on FIG. In this embodiment, as shown in the figure, the first communication hole 30 is formed in the same manner as in the previous embodiment, and the second communication hole 32 is opened to the cylinder bores 22 and 23. Therefore, according to this embodiment, during the suction stroke, the second communication hole 32 becomes a so-called suction hole, and the pressure in the hole bottom cavity 28a of the mounting hole 28 decreases to approximately the same level as the pressure in the cylinder bores 22, 23. Therefore, a large amount of gas flows into the first communication hole 30 through the gap between the shoe 24 and the piston spherical portion 31, and the lubrication effect of the oil in the gas on the spherical portion can be further improved. Note that during the discharge stroke, the second communication hole 32 is closed by the suction valve 27, so the cylinder bore 2
The compressed gas in 2 and 23 will not blow out to the swash plate chamber 18 side.

In the illustrated example, the bearing device is composed of a hemispherical shoe 24, but the bearing device may be composed of a combination of a ball and a shoe. Further, the suction valve 27 may be attached using bolts instead of the rivets 29.

As described in detail above, the present invention provides a swash plate compressor having a suction hole and a suction valve at the top of the piston. By opening it to the outer surface of the piston through the relief hole,
It is possible to prevent air from remaining trapped in the hollow space at the bottom of the hole, thereby eliminating problems such as falling out of rivets and rust due to the trapped air. Further, in the present invention, the first communication hole serving as the relief hole is opened to the spherical surface that is the engagement surface between the piston and the bearing device, and the second communication hole is opened near the entrance of the suction hole or to the cylinder bore. By doing so, an active gas flow is generated in the gap between the shoe and the spherical surface of the piston, thereby increasing the lubrication effect of the oil in the gas on the spherical surface, thereby reducing wear and preventing seizure.

Note that as a means for lubricating the spherical surface of the piston, a method in which a small hole is formed in the piston to communicate the cylinder bore and the spherical surface has been proposed.
In the case of this type, compressed gas remains in the small hole when the discharge stroke is completed, and this residual compressed gas expands during the suction stroke, deteriorating the suction efficiency. However, the present invention described above It is superior in that it can enhance the lubrication effect of the spherical surface without causing any disadvantages.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a side cross-sectional view of a swash plate compressor, FIG. 2 is a cross-sectional view showing a communication portion between front and rear discharge chambers, and FIG. 3 is a cross-sectional view of a swash plate compressor. FIG. 1, 2... Cylinder block, 5, 6... Housing, 16... Drive shaft, 18... Swash plate chamber, 19
...Swash plate, 22, 23...Cylinder bore, 24...
...Show, 25... Piston, 26... Suction hole,
27... Suction valve, 28... Mounting hole, 28a... Hole bottom cavity, 29... Rivet, 30... First communicating hole, 31... Spherical surface portion, 32... Second communicating hole.

Claims (1)

[Scope of Claims] 1. A piston is moored via a bearing device to a swash plate that is tilted and fixed on a drive shaft, and a swash plate chamber that rotatably accommodates the swash plate and a piston are provided at the top of the piston. In a swash plate compressor having a suction hole that communicates with a cylinder bore that is accommodated in a reciprocally slidable manner and a suction valve that opens and closes the suction hole, a bolt hole for installing the suction valve or A swash plate type compressor characterized in that the bottom cavity of a rivet hole is opened to the outer surface of the piston by a relief hole. 2. The swash plate compressor according to claim 1, wherein the relief hole for the hole bottom cavity is open to a spherical surface of a bearing device of the piston. 3. Claim 1, characterized in that one of the relief holes for the hole bottom cavity is opened to a spherical surface part of the bearing device of the piston, and the other one is opened near the entrance of the suction hole. The swash plate compressor described in Section 1. 4. One of the relief holes for the hole bottom cavity is open to a spherical part of the bearing device of the piston, and the other one is opened to the cylinder bore via a suction valve. The swash plate compressor according to item 1.