JPH03153912A - Piston device - Google Patents

Abstract

PURPOSE:To realize relaxation of machining and assembling accuracies in a piston device in which a piston is connected through a piston pin to the small end part of a connecting rod having a large end part and the small end part by using a spherical bearing in at least of the large end part and the small end part. CONSTITUTION:With a piston device, a connecting rod 2 having a large end part 1A and a small end part 3 on its both ends is connected through a piston pin 4 to a piston 5 at the small end part 3. The inside of the large end part 1A loaded with a spherical bearing 6 is spherically machined, the divided journal type bearing is fitted to the inside, and the inside diameter part is fitted to a mating rotary shaft to be formed into a reasonably machined surface. With the piston device incorporated, for example, into a closed type compressor, since the spherical bearing 6 has the degree of freedom in all directions of rotation, the deviation of squareness between a rotary shaft fitted to the inside diameter of the large end part 1A and the center-axis of the inside diameter of a cylinder into which the outside diameter of the piston 5 is fitted, is absorbed, and a relative position of the rotary shaft and the piston can be always traced even in the operation. Relaxation of the accuracies of machining and assembling various parts, stabilized sliding characteristic and starting characteristic can thus be realized.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a piston device, and is applied to, for example, a hermetic compressor for a refrigerator, and is particularly suitable for reducing processing accuracy and assembly accuracy. This invention relates to a piston device.

[Conventional technology]

A conventional piston device will be explained with reference to FIGS. 5 and 6.

FIG. 5 is a sectional view of a conventional piston device, and FIG. 6 is a longitudinal sectional view of a main part of a hermetic compressor to which the piston device of FIG. 5 is applied.

In the piston device shown in FIG. 5, a connecting rod 2 having a large end 1 and a small end 3 at both ends is connected to a piston 5 at the small end 3 via a piston pin 4.

When this piston device is assembled into a hermetic compressor as shown in FIG. It is something to match. In FIG. 6, 9 indicates a frame, and 10 indicates a closed container.

In addition, related piston devices of this type include:
For example, %Kan Sho 60-125785 can be mentioned.

[Problem to be solved by the invention]

As mentioned above, since the piston device of the prior art is used by being incorporated into a hermetic compressor, the large end 1 of the piston device
High precision is required for the perpendicularity between the inner diameter center axis of the piston 5 and the outer length center axis of the piston 5, and the perpendicularity between the center axis of the rotary shaft 7 and the inner diameter center axis of the cylinder 8. For this reason, it was necessary to strictly control the dimensional accuracy of each component during processing and assembly.

Furthermore, due to the lack of precision in the perpendicularity, there is a fear that wear of the sliding portion may be accelerated, deterioration of starting characteristics, etc. may occur.

The present invention was made in order to solve the problems of the above-mentioned conventional technology, and it alleviates processing accuracy and assembly accuracy, prevents wear,
It is an object of the present invention to provide a piston device that makes it possible to improve starting characteristics.

[Means to solve the problem]

In order to achieve the above object, a piston device according to the present invention includes a connecting rod having a large end and a small end, and a piston is connected to the small end via a piston pin. In the piston device, a spherical bearing is used on the inner diameter of at least one of the large end portion and the small end portion.

[Effect]

By using a spherical bearing at the large or small end of the connecting rod, degrees of freedom are added in all rotational directions of each center shaft, so that the perpendicularity between the large end and the center axes of the piston is improved. In addition, the perpendicularity deviation between the rotating shaft and the central axis of the inner diameter of the cylinder in a device body into which the piston device is incorporated, for example, a hermetic compressor, is also absorbed. Furthermore, the sliding properties are improved.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 is a cross-sectional view of a piston device according to one embodiment of the present invention, FIG. 2 is a cross-sectional view of a piston device according to another embodiment of the present invention, and FIG. 5 is a cross-sectional view of a piston device according to another embodiment of the present invention. FIG. 4, a cross-sectional view of the piston device according to the embodiment, is an explanatory diagram of the centripetal action of the spherical bearing of FIG. 3. In each figure, the same reference numerals as in FIG. 5 indicate parts equivalent to the prior art.

In the piston device shown in FIG. 1, a connecting rod 2 having a large end and a small end 3 at both ends is connected to a piston 5 at the small end 3 via a piston pin 4.

In this embodiment, a spherical bearing 6 is employed on the inner diameter of one large end. The inside of the large end where the spherical bearing is to be mounted is machined into a spherical surface, and a journal type spherical bearing divided into multiple parts is fitted into it. The inner diameter portion is formed on a properly machined surface for fitting with the mating rotating shaft. Note that a commercially available spherical bearing may be used.

The piston device shown in FIG.
When installed in the hermetic compressor shown in the figure, the single spherical bearing 6 has a degree of freedom in all rotational directions, so the large end 1Ao^ is slightly fitted between the rotating shaft 7 and the piston 5. It absorbs the deviation of the perpendicularity of the center axis of the inner diameter of the cylinder 8 to which the outer diameter is fitted. In addition, since the relative position of the rotating shaft and piston can always be traced even during operation, it is possible to reduce the machining accuracy of each part, ease the assembly accuracy, and achieve stable sliding and starting characteristics. becomes.

According to this embodiment, it is possible to realize a piston structure that absorbs errors in one dimension well, that is, a piston structure that is insensitive to dimensional variations, and stable sliding characteristics, so it is possible to reduce the cost by reducing processing accuracy and assembly accuracy. We can provide highly reliable piston devices.

Next, in the piston device of the embodiment shown in FIG. 2, a spherical bearing 6A is employed on the inner diameter of the small end portion 3A.

According to the embodiment shown in FIG. 2, the same effects as those described in the embodiment shown in FIG. 1 can be expected.

Next, in the piston device of the embodiment shown in Fig. 5.4, the center of gravity G0 of the sphere forming the spherical bearing 6B.

It is located vertically above the center of gravity G of the large end 1B.

As shown in Figure 4, if the large end IBK collapses,
A moment in the opposite direction to the tilting direction is generated at the center of gravity G of the large end portion 1B, and an alignment action can be performed, so that stable movement is possible.

According to the embodiment shown in FIG. 3.4, the same effects as those of the previous embodiments are expected.

By forming the spheres of the spherical bearings in each of the above embodiments from a sintered material with high oil-free lubricity, higher reliability can be obtained.

In each of the above embodiments, examples have been described in which spherical bearings are used at the large end or the small end, but needless to say, spherical bearings may be used at both ends.

〔Effect of the invention〕

According to one aspect of the present invention, as described in detail above.

It is possible to provide a piston device that can reduce processing accuracy and assembly accuracy, prevent wear, and improve starting characteristics.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a piston device according to one embodiment of the present invention, FIG. 2 is a cross-sectional view of a piston device according to another embodiment of the present invention, and FIG. 5 is a cross-sectional view of a piston device according to another embodiment of the present invention. A sectional view of the piston device according to the embodiment, FIG. 4 is an explanatory diagram of the centripetal action of the spherical bearing in FIG. tx3, FIG. 5 is a sectional view of the conventional piston device, and FIG. 1 is a vertical sectional view of a main part of a hermetic compressor to which the above is applied. Explanation of symbols 1, 1A, IB...-Big end, 2... Connecting rod, 5.
3A... Small end, 4... Piston pin, 5... Piston, 4, 4A, 6B... Spherical bearing, 7... Rotating shaft, 8... Cylinder, 10... Sealing container. Fig. 1 Fig. 4 Fig. 5・-・Three-sided bearing

Claims (1)

[Scope of Claims] 1. A piston device comprising a connecting rod having a large end and a small end, and a piston connected to the small end via a piston pin, wherein the large end and the small end are connected to each other via a piston pin. A piston device characterized in that a spherical bearing is used for the inner diameter of at least one of the ends. 2. The center of gravity of the spheres constituting the spherical bearing is located vertically above the centering range of the center of gravity of either the large end or the small end into which the spheres are fitted. A piston device according to claim 1. 3. The piston device according to claim 1 or 2, wherein the sphere constituting the spherical bearing is made of a sintered material with high oil-free lubricity. 4. In a hermetic compressor in which an electric motor section and a compression mechanism section are housed in a closed container, the outer diameter of the piston of the piston device according to any one of claims 1 to 3 is set to the inner diameter of the cylinder of the compression mechanism section. , a hermetic compressor characterized in that the inner diameter of the large end is fitted to the outer diameter of the rotating shaft of the electric motor.