JPH0311165A - Swash plate type compressor - Google Patents

Abstract

PURPOSE:To suppress the beating noise due to the collision between a piston connection part and the outer peripheral surface of a swash plate and reduce noise by forming thinned parts so as to offset the revolution imbalance around a piston shaft, onto the outer periphery in the vicinity of the connection part of the piston. CONSTITUTION:A swash plate 2 is fixedly installed onto a shaft 1. A piston 5 is retained onto the swash plate 2 through slippers 3a and 3b and balls 4a and 4b which act as universal joints. Thinned parts 5c and 5c' are formed on the outer peripheries of 5b and 5b' in the vicinity of the connection part 5a of the piston 5 so as to offset the revolution imbalance around a piston shaft due to the weight of a piston connection part 5a. The turning moment due to the weight of the piston connection part 5a is softened, and the beating sounds due to the collision between the piston connection part 5a and the outer peripheral surface of the swash plate 2 can be reduced. Thus, noise can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a double-headed piston type swash plate compressor used in automobile air conditioners and the like.

[Conventional technology]

In order to reduce the hammering noise that occurs when the piston connection portion collides with the outer circumferential surface of the swash plate, there is a method of fundamentally restraining the rotation of the piston or weakening the rotational force of the piston. A known example of the former method is a method of restraining the rotation of the piston by providing a projection or the like on the piston and providing a groove or the like for holding the projection on the cylinder side, as described in Utility Model Application Laid-Open No. 62-133973. There is. A known example of the latter is a method of weakening the rotational force of the piston by forming a solid lubricant film such as fluorinated ethylene on the friction interface between the piston and the universal joint, as described in Japanese Patent Publication No. 11195/1983. be.

[Problem to be solved by the invention]

In the conventional technique described above, for example, in the method of restricting the rotation of a piston by providing a projection on the piston, a gap exists between the projection and the groove on the cylinder side that holds the projection.

There was a problem in that a tapping sound was generated when the protrusion came into contact with the groove wall surface. In addition, with the method of forming a solid lubricant film on the friction interface between the piston and the universal joint to weaken the rotational force of the piston, the solid lubricant film will wear out over a long period of operation, and the piston base material and the universal joint will become damaged. When there is direct friction, there is a problem in that the piston loses its effectiveness in weakening the rotational force of the piston.

The purpose of the present invention is to reduce the rotational force of the piston by eliminating the unbalance of rotation around the piston shaft due to the weight of the piston connection, and to reduce the hammering noise that occurs when the piston connection and the outer peripheral surface of the swash plate collide. The purpose is to prevent it.

[Means to solve the problem]

The above object can be achieved by providing a thin strip on the outer periphery of the piston near the piston connecting portion so as to cancel out the coaxial imbalance around the piston axis caused by the weight of the piston connecting portion.

[Effect]

By thinning the outer periphery of the piston, unbalanced rotation around the piston axis due to the weight of the piston connecting portion is eliminated. Therefore, the rotational force due to the weight of the piston connecting portion is alleviated, and the hitting noise caused by the collision between the piston connecting portion and the outer surface of the swash plate can be reduced.

〔Example〕

Embodiments of the present invention will be described using FIGS. 1 and 2. Shaft 1 that rotates by receiving power from a drive system (not shown)
A swash plate 2 is fixedly attached to the swash plate 2.

The swash plate 2 is provided with a slipper 3a that acts as a universal joint.
, 3b and balls 4a, 4b, the piston 5 is held in place. Here, the outer periphery 5b, 5b' of the piston 5 near the connecting portion 5a is provided with a thinning portion 5c so as to counteract the rotational imbalance around the piston axis due to the weight of the piston connecting portion 5a.

5c' is provided. A plurality of cylinder bores 7 for reciprocatingly holding the piston 5 are arranged around the shaft 1 in the cylinders 6a and 6b that rotatably hold the shaft 1. Further, the cylinders 6a, 6
A discharge valve 9a is connected to the end face of b through suction valves 8a and 8b.
, 9b are provided.

The cylinder heads 10a, 10b include a low pressure chamber 11a,
side cover 13 having llb and high pressure chambers 12a and 12b
Patchkin 14a by a, 13b.

It is fixed to the end surfaces of the cylinders 6a, 6b via 14b.

Next, the operation will be explained. When the shaft 1 rotates by receiving power from a drive system (not shown), the swash plate 2 fixed to the shaft 1 performs a rotational oscillating motion.

Due to the rotational swing movement of the swash plate 2, the piston 5 is
reciprocates within the cylinder bore 7.

Here, the balls 4a, 4b and the piston 5 are in contact at a point P as shown in FIG. When the piston 5 reciprocates within the cylinder bore 7, the contact point P rotates around with a radius of -5 inches θ (d is the ball diameter and θ is the nail extraction angle), as shown in FIG. 4, and as a result, the piston 5 Under the influence of the twisting load, the piston connecting portion 5a rotates in the same direction as the rotational direction of the swash plate 2, and the piston connecting portion 5a comes into contact with the outer peripheral surface 2a of the swash plate. At this time, if the above-mentioned contact always occurs, the sound generated at this part is a continuous sliding sound and cannot be determined as an abnormal sound. However, the swash plate compressor is
6 cylinders), the cross section perpendicular to the axis as shown in Fig. 6 (10 cylinders), and in a conventional piston as shown in Fig. 7, the direction of rotation of the piston due to the rotation of the contact point P,
There is a piston in which the direction of rotation of the piston due to the weight of the piston connecting portion 5a is reversed. In this case, when the piston 5 is in the compression stroke, the piston 5 rotates in the direction of rotation of the swash plate 2, and the piston connecting portion 5a is in contact with the outer peripheral surface 2a of the swash plate. When the pressure is balanced, the piston 5 is moved by the weight of the piston connecting portion 5a.
rotates in the opposite direction and moves away from the swash plate outer circumferential surface 2a.The piston load increases and is again affected by the drag load.
When the piston 5 rotates in the rotational direction of the swash plate 2, the piston connecting portion 5a collides with the outer peripheral surface 2a of the swash plate, producing abnormal noise.

However, in the case of this embodiment, the piston 5c is provided on the outer periphery of the piston 5 so as to cancel out the weight of the piston connection part 5a, so that the rotation of the piston due to the weight of the piston connection part 5a is eliminated. As a result.

The piston 5 receives only the drag load of the contact point P, and the piston connecting portion 5a and the swash plate outer circumferential surface 2a are always in contact with each other, eliminating any abnormal noise caused by collision.

〔Effect of the invention〕

According to the present invention, the rotational imbalance around the piston axis due to the weight of the piston connection part is eliminated by thinning the outer circumference of the piston, so there is no hitting sound caused by the collision between the piston connection part and the outer peripheral surface of the swash plate, and noise is reduced. be able to.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a piston showing an embodiment of the present invention;
The figure is a longitudinal sectional view of a swash plate compressor showing an embodiment of the present invention, FIG. -1 line enlarged sectional view, FIGS. 5 and 6 are axially perpendicular sectional views of the swash plate compressor, and FIG. 7 is a perspective view showing a conventional piston. 2... Swash plate, 2a... Swash plate outer peripheral surface, 3... Slipper, 4... Ball, 5... Piston, 5a... Piston connection portion, 5b, 5b'... Piston Outer circumference, 5C
, 50' ... Meat theft on the outer periphery of the piston.

Claims (1)

[Claims] 1. A shaft rotatably inserted into the shaft holes of a pair of left and right cylinder blocks, and a swash plate fixed to the shaft;
A plurality of pistons are moored to the swash plate via a slipper and a ball as a universal joint, and the pistons reciprocate within a cylinder bore provided in the cylinder block due to the rotational oscillation of the swash plate. What is claimed is: 1. A swash plate compressor characterized in that a swash plate is provided on the outer periphery of the piston in the vicinity of the connection portion thereof so as to counteract rotational imbalance around the piston axis due to the weight of the piston connection portion.