JPH10318143A - Hermetic motor-driven compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hermetic motor-driven compressor which can prevent occurrence of abnormal noise caused by intermittent contact of a connecting rod with a washer due to inclination of a bearing and a shaft. SOLUTION: In this hermetic motor-driven compressor, when a connecting rod and a U-like washer 17 are inserted in a hollow part 16 of a piston 6, the washer 17 abuts with the hollow part 16 at four points 16a, 16b, 16c, 16d while a clearance is held between the connecting rod and the U-like washer 17, and the washer 17 is formed in such a shape that it is curved toward the connecting rod in the vicinity of the piston pin 19. Accordingly, an effect for damping the vertical motion of the connecting rod can be exhibited so as to prevent occurrence of resonation of the U-like washer 17, and therefore, exciting force transmitted from the piston and the cylinder is decreased so as to prevent occurrence of abnormal sound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for reducing noise in a joint between a piston and a connecting rod of a hermetic electric compressor.

[0002]

2. Description of the Related Art Conventionally, the structure of a connecting portion between a piston and a connecting rod of a hermetic electric compressor is disclosed in Japanese Patent Application Laid-Open No. 8-30333.
No. 49 and JP-A-1-80683 are known.

FIG. 4 is a sectional view of a conventional hermetic electric compressor. Reference numeral 1 denotes a hermetic case, 2 denotes a compressor portion, 3 denotes a motor portion, and the compressor portion 2 and the motor portion 3 are elastically supported by the hermetic case 1. ing. In the compressor unit 2, 4 is a shaft, 4a is a crank part of the shaft 4, 5 is a bearing, 6 is a piston, 7 is a connecting rod, 8
Is a cylinder, 9 is a compression chamber, and a piston 6 reciprocates in the cylinder 8 via a connecting rod 7 connected to the crank part 4a of the shaft 4, thereby compressing the refrigerant gas. Motor unit 3
, 11 is a stator, and 12 is a rotor.

FIGS. 5 and 6 are a sectional view and an exploded perspective view of a conventional assembly of a piston 6 and a connecting rod 7, respectively.
Is a U washer, 19 is a piston pin, and when assembling the piston 6 and the connecting rod 7,
The small end portion 7a of the connecting rod and the U washer 17 are inserted into the piston pin insertion hole 6a in the hollow portion 16 of the piston 6, and the piston pin through hole 18a of the U washer 17
The piston pin 19 is inserted by aligning the hole 7a at the small end of the connecting rod and the piston pin 19 is inserted. Further, the piston pin through hole 18b of the U washer 17 and the piston pin insertion hole 6b of the hollow portion 16 of the piston 6 are aligned. Then, the piston 6 and the connecting rod 7 are assembled. At this time, a clearance is provided between the connecting rod small end portion 7a and the U washer 17, and the bottom of the U washer 17 is loosely fitted into the hollow portion 16. I have.

[0005] The operation of the reciprocating electric compressor constructed as described above will be described. With the rotation of the rotor 12, the shaft 4
The piston 6 reciprocates in the cylinder 8 via a connecting rod 7 connected to the crank portion 4a of the compressor, compresses the refrigerant gas in the compression portion, and discharges the refrigerant gas to the system through a discharge pipe (not shown).

[0006] Here, the reciprocating motion of the compressor section 2 generates rotational vibration in the connecting rod 7 connected to the crank section 4a of the shaft 4. In the compression step, a compression load is applied to the piston 6, so that the piston 6 is tilted in the cylinder 8 and the bearing 5
The shaft 4 is inclined by the clearance of the shaft 4 and the strength of the shaft 4. The inclination of the shaft 4 causes the connecting rod 7 to move up and down, so that the casting surface of the hollow portion 16 of the piston 6 and the small end 7a of the connecting rod come into contact with the swinging motion, and the end surface of the small connecting rod end 7a is worn. I do. For this purpose, a U washer 17 having a smooth surface is inserted into a portion that comes into contact with the connecting rod small end 7a.

[0007]

However, in the above configuration, the connecting rod moves up and down due to the inclination of the bearing and the shaft, and an impact occurs due to intermittent contact between the connecting rod and the U washer. This impact becomes a force for exciting the U washer, and furthermore, a resonance occurs between the connecting rod and the U washer, and this resonance is transmitted to the piston and the cylinder to generate an abnormal sound.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to prevent abnormal noise generated from resonance between the connecting rod and the U washer.

[0009]

In order to solve the above-mentioned problems, according to the present invention, the hollow portion of the piston and both arms of the U washer contact each other at four points to stabilize the gap between the U washer and the connecting rod. The vertical movement of the connecting rod is regulated.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is characterized in that the hollow portion of the piston and both arms of the U-washer each have four arms.
At the point and contact with the small end of the connecting rod near the piston pin, so both arms of the U-washer buffer the minute vertical movement of the connecting rod due to the compressive load. This has the effect of avoiding resonance of the arm.

According to a second aspect of the present invention, the hollow portion of the piston and the arms of the U washer contact each other at four points, contact the small end of the connecting rod near the piston pin, and bend R to R8 to R8. The U-washer has two arms that buffer the vertical movement of the connecting rod due to the compression load, so that a stable vertical movement of the connecting rod is obtained. Has the effect of reducing the impact force of the connecting rod.

According to a third aspect of the present invention, the hollow portion of the piston and the two arms of the U washer abut at four points, respectively, come into contact with the small end of the connecting rod near the piston pin, and have a bending angle of 10 °. ４０40 °, and both arms of the U-washer buffer the minute vertical movement of the connecting rod due to the compression load, so that a stable vertical movement of the connecting rod is obtained. Since it has an initial load that pushes against the hollow portion, it has an effect of eliminating minute chattering generated between the U washer and the hollow portion of the piston.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. The basic configuration and operation are the same as those of the conventional example, and the same components are denoted by the same reference numerals, and the description of the overlapping portions will be omitted.

In FIG. 1, reference numeral 16 denotes a hollow portion of the piston 6, 16a, 16b, 16c, and 16d denote four points which come into contact with the hollow portion 16 of the piston when a U washer is inserted. , And the U washer 17 has a shape that bends toward the connecting rod 7, so that the U washer 17 has a function of providing a buffering effect even if the connecting rod 7 moves up and down.

A second embodiment of the present invention will be described with reference to FIG. In FIG. 3, A is a U washer 17
In the example of bending R, bending is performed from the center of the piston pin insertion hole of both arms, and the R dimension is R8 to R40,
A shape that curves toward the connecting rod 7 side of the U washer 17 can be secured.

A third embodiment of the present invention will be described with reference to FIG. In FIG. 3, B is a U washer 17
By setting the bending angle to 10 ° to 40 °, there is an effect of ensuring four points in contact with the hollow portion 16 of the piston even when the dimensions of the hollow portion 16 of the piston have a tolerance.

[0017]

As is apparent from the above embodiment, according to the first aspect of the present invention, since the U-washer has a structure in which the both arms of the U-washer are securely in contact with the hollow portion of the piston at four points, the compression is achieved. When the piston of the machine part reciprocates, the bearing and the shaft are inclined by the clearance, so that rotational vibration is transmitted to the connecting rod connected to the crank part of the shaft, and this vibration causes the connecting rod to move up and down and hit the U washer. The U-washer and the hollow part of the piston are securely contacted at four points to prevent the U-washer from resonating, and the U-washer is curved to the connecting rod side, thereby damping the shock vibration when the connecting rod hits. Is obtained.

Further, by using the inventions of the second and third aspects together, the above-mentioned effect can be exhibited.

[Brief description of the drawings]

FIG. 1 is an assembled sectional view of a piston and connecting rod according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of FIG. 1;

FIG. 3 is a plan view of a U washer showing a second and a third embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of an electric compressor showing a conventional embodiment.

FIG. 5 is an assembled sectional view of a piston connecting rod showing a conventional embodiment.

FIG. 6 is an exploded perspective view of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealing case 2 Compressor part 3 Motor part 6 Piston 6a Piston pin hole 6b Piston pin hole 7 Connecting rod 7a Connecting rod small end part 7b Connecting rod small end part hole 16 Piston hollow part 16a Contact part between hollow part and U washer 16b Contact portion between hollow portion and U washer 16c Contact portion between hollow portion and U washer 16d Contact portion between hollow portion and U washer 17 U washer 18a Piston pin through hole 18b Piston pin through hole 19 Piston pin

Continued on the front page (72) Inventor Hiroshi Sasano Matsushita Refrigerator Co., Ltd. 4-5-2, Takaidahondori, Higashiosaka City, Osaka

Claims (3)

[Claims] 1. A connecting rod for accommodating a compressor section and an electric motor section in a closed case, and having holes having parallel axes at both ends of a small end and a large end in the compressor section, respectively. A piston having a piston pin insertion hole and a hollow portion into which the small end portion of the connecting rod is inserted; and a substantially U-shaped, free end having a piston pin through hole at each free end, the hollow portion of the piston and the small end of the connecting rod A U-washer that is elastically fitted between the portion and a piston pin inserted through the piston pin insertion hole, a small end of the connecting rod, and a through-hole of the U washer, and rotatably holds the connecting rod. The arm of the U washer contacts the hollow portion of the piston at two or more points at positions sandwiching the piston pin, and is curved toward the small end of the connecting rod near the piston pin. And a hermetic electric compressor. 2. The hermetic electric compressor according to claim 1, wherein the bending R of the warp portions of the both arms of the U washer is R8 to R40. 3. The hermetic electric compressor according to claim 1, wherein the bending angle of both arms of the U washer is formed to be 10 ° to 40 °.