US3664771A

US3664771A - Hermetically sealed electric compressor

Info

Publication number: US3664771A
Application number: US113037A
Authority: US
Inventors: Akira Suzuki; Keisuke Ida
Original assignee: Tokyo Shibaura Electric Co Ltd
Current assignee: Toshiba Corp
Priority date: 1970-02-20
Filing date: 1971-02-03
Publication date: 1972-05-23
Anticipated expiration: 1989-05-23

Abstract

A HERMETICALLY SEALED COMPRESSOR COMPRISING A COMPRESSOR BODY ELASTICALLY SUPPORTED IN A SEALING CASE AN A PROTECTOR SO DISPOSED AS TO ENCLOSE THE LOWER END OF THE REVOLVING SHAFT OF AN ELECTRIC MOTOR CONSTITUTING AN ELEMENT OF SAID BODY AND PROVIDED WITH AT LEAST ONE REPULSING MEANS WHEREIN, WHEN THE REVOLVING SHAFT ROTATES ALONG THE INNER WALL OF THE PROTECTOR UPON THE HEAVY SHAKING OF THE COMPRESSOR BODY, AND THE LOWER END OF THE SHAFT IS FORCED BACK TO THE ORIGINAL POSITION OF THE PROTECTOR BY THE REPULSING MEANS, THEREBY PREVENTING SAID ROTATION FROM BEING CARRIED TO EXCESS.

Description

May 23, 1972 AKlRA SUZUK| ETAL 3,664,771

HERMETICALLY SEALED ELECTRIC COMPRESSOR Filed Feb. 3, 1971 FIG.

FIG. 2

FIG. 4

FIG. 3

FIG. 5

United States Patent US. Cl. 417-410 4 Claims ABSTRACT OF THE DISCLOSURE A hermetically sealed compressor comprising a compressor body elastically supported in a sealing case and a protector so disposed as to enclose the lower end of the revolving shaft of an electric motor constituting an element of said body and provided with at least one repulsing means wherein, when the revolving shaft rotates along the inner Wall of the protector upon the heavy shaking of the compressor body, and the lower end of the shaft is forced back to the original position of the protector by the repulsing means, thereby preventing said rotation from being carried to excess.

BACKGROUND OF- THE INVENTION The present invention relates to a hermetically sealed electric compressor and more particularly to such compressor having at least one repulsing means provided in a protector intended to prevent the lateral shaking of a compressor body. With a conventional compressor of such type wherein there is elastically supported in a sealing casing a compressor body consisting of a compressing unit and an electric motor, the lower end of the revolving shaft of the electric motor is made to abut against the inner wall of a cylindrical protector so disposed as to enclose said end, thereby preventing the compressor body from striking against the inner wall of the sealing casing upon its heavy shaking due to impacts being applied thereto. However, it often happens with such cylindrical protector that when the compressor body rocks sidewise during the rotation of the revolving shaft to cause the shaft to touch the inner wall of the protector, then the shaft continues revolving while rotating itself along the inner wall of the protector, failing to be brought back to its original position. Said sliding has resulted in not only the occurrence of noises but also the generation of fine iron particles, possibly causing the failure of the compressor itself.

SUMMARY OF THE INVENTION The present invention has been accomplished to eliminate the aforementioned drawbacks and is characterized in that the protector assumes a cylindrical form comprising in cross section a pair of half circles whose centers are laterally displaced from each other or a substantially helical shape and the inner wall of said protector is provided with at least one repulsing means.

An object of the present invention is to provide a hermetically sealed electric compressor wherein the revolving shaft is forced back to its original position by at least one repulsing means constituting part of the inner wall of the protector or formed by one of the edges thereof so as to be prevented from continuing its rotation in close contact with the inner wall of the protector, thereby saving the compressor from the resulting noises and failure.

Another object of the present invention is to provide a hermetically sealed electric compressor provided with a protector for preventing the occurrence of accidents due 3,664,771 Patented May 23, 1972 to the compressor body striking upon its heavy shaking against the inner wall of the sealing casing.

BRIEF EXPLANATION OF THE DRAWINGS FIG. 1 is a sectional view of a hermetically sealed electric compressor according to an embodiment of the present invention;

FIG. 2 is a perspective view of a protector according to an embodiment of the invention used in said compressor;

FIG. 3 is a plan view of the protector of FIG. 2;

FIG. 4 is a perspective view of a protector according to another embodiment of the invention used in the compressor of FIG. 1; and

FIG. 5 is a plan view of the protector of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1, numeral 1 denotes a casing, in which there is elastically suspended a compressor body 2 by means of spring hangers 3 fixed to the upper part of the inner wall of the casing and springs 4 fitted to said hangers 3.

The compressor body 2 comprises a frame 5, an electric motor 6 having a revolving shaft 7 rotatably fitted into the center of the frame 5 and a compressing unit 8 operated by the motor 6. The electric motor 6 consists of the revolving shaft 7, a rotor 9 substantially integrally fitted thereto and a stator 10 suspended from the underside of the frame 5. The compressing unit 8 is formed of a cylinder 11 fixed to the upper surface of the frame 5 and a piston 12 reciprocating through the cylinder 11. To the upper end of the revolving shaft 7 is secured a crank shaft 13 at a point displaced from the axial center of the revolving shaft 7, said crank shaft 13 being connected to the piston 12 through a scotch yoke 14.

In this embodiment, the compressing unit 8 is mounted on the upper surface of the frame 5 and the electric motor 6 is fitted to the underside thereof, but said positions may be reversed.

At the inner bottom of the casing 1 is stored a lubricant 15, which is normally designed to pass through a lubricant passage (not shown) bored lengthwise through the revolving shaft 7 so as to wet the rotating and sliding parts of the compressor. The revolving shaft 7 is here assumed to rotate clockwise.

Throughout FIGS. 1 to 3, numeral 16 is a protector for preventing the compressor body 2 from striking against the inner wall of the casing 1 when it shakes broadly under external impacts. The protector 16 is generally fixed to the inner bottom wall of the casing 1 so as to surround the lower end of the revolving shaft 7 with said end disposed at the center of the protector 16. This protector 16 is made of iron or other materials resistant to the chemical action of the lubricant 15 as well as to mechanical shocks.

As seen from FIGS. 2 and 3, the protector assumes a deformed cylindrical form consisting in cross section of a pair of half-circles 'whose centers are laterally displaced from each other, that is, a substantially helical shape. In the case of this embodiment, the center of the lower half-circle is displaced, as illustrated in FIG. 3, to the right of that of the upper half-circle. Where, however, the revolving shaft 7 rotates counterclockwise, said displacement takes place to the opposite side. Namely the revolving shaft 7 makes a precessional movement in a reverse direction to its own revolution.

T he vertical edges of said two substantially semicircular members :are integrally joined together with a smooth surface presented on both inside and outside, said joint constituting repulsing means 17. Referring to FIG. 3, it is further preferred that the inner wall of the repulsing means 17 be inclined slightly, for example, about 5 degrees toward the outside of the protector with respect to a line connecting the centers of both semicircular members. At the upper part of the repulsing means 17 is formed a notch 18 so as to allow the lubricant 15 to pass therethrough into the protector 16. In this case, the bottom plane of said notch 18 should be located above the lower end of the revolving shaft 7. Where the motor unit is mounted on the frame and the compressor unit is fitted to the underside thereof, there is no need to condut the lubricant 15 into the protector, so that the notch 18 may be omitted. 1

There will now be described the operation of this embodiment. When the electric motor 6 drives the revolving shaft 7, the compressing unit 8 is operated by means of the crank shaft 13 and scotch yoke 14 to compress a refrigerant introduced through an inlet tubing (not shown) and conduct it to an outlet tubing (neither shown). Normally the lower end of the revolving shaft 7 rotates substantially at the center of the protector 16. Even when the lower end of the revolving shaft 7 strikes against the inner wall of the protector 16 upon the broad shaking of the compressor body under external or internal impacts, the compressor body 2 does not rock beyond that extent, being prevented from impinging on the inner wall of the casing 1.

When the lower end of the revolving shaft 7 is driven against the inner wall of the protector 16, the shaft 7 sometimes rotates along said inner wall counterclockwise as viewed from FIG. 3. In this case, the protector 16 according to this embodiment causes the revolving shaft 7 to rotate counterclockwise only by one half-circle at most along said inner wall, but upon arrival at the first repulsing means 17 to be forced back to the original position of the protector 16. Accordingly, the occurrence of noises and/or compressor failure resulting from contact between the revolving shaft 7 and the inner wall of the protector 16 is minimized.

Long use of a compressor sometimes leads to sedimentation of foreign matter such as fine iron particles or impurities contained in a lubricant 15 at the bottom of a lubricant reservoir. In the protector 16 of the present invention, however, there is provided the notch 18 at the upper part of the repulsing means, causing only that portion of the lubricant 15 which contains least amounts of foreign matter to be introduced into the protector 16, so that a compressor of the type where the lubricant 15 is conducted from the lower end of the revolving shaft 7 to the rotating and sliding parts is effectively saved from accidents resulting from entrainment of foreign matter with the lubricant 15.

FIGS. 4 and illustrate a protector according to another embodiment of the present invention used in a hermetically sealed compressor. Numeral 116 represents a protector which is made of the same material as the protector 16 of the preceding embodiment. The protector 116 is formed of a spiral piece rolled counterclockwise substantially only once. The outer vertical edge of the joint loosely overlaps the inner vertical edge, whose face constitutes repulsing means 117.

In this case, it is preferred that a plane defined by both edge faces of the protector 116 be slightly inclined toward the outside of the protector 116 with respect to a normal line connecting said inner vertical edge constituting the repulsing means 117 and the center of the protector 116.

With a compressor wherein the revolving shaft 7 rotates counterclockwise, the single piece constituting the protector 116 is rolled clockwise. Between the outside of the repulsing means 117 and the opposite inner wall of the protector 116 is provided a clearance 119 'narrower than the radius of the revolving shaft 7. With a compressor containing a protector 116 constructed asIdescribed above, even when the lower end of the revolving shaft 7 rotates in contact with the inner wall of the protector 116 due to the heavy shaking of the compressor body 2, said lower end is driven back inward of the protector 116 upon 'im pingement on the repulsing means to be instantly removed from the inner wall of the protector 116.

In the embodiment of FIG. 5, the lubricant 15 is allowed to flow into the protector 116 through the clearance 119, even without particularly providing a notch as in FIGS. 2 and 3. Further, the embodiment of FIG. 5 hasv the advantage that it is of simpler construction and easier to fabricate than that of the preceding embodiment.

What we claim is:

1. A hermetically sealed electric compressor comprising a casing; a compressing unit received in said casing and formed of a frame, an electric motor whose revolving shaft is rotatably fitted into the frame and a compressing unit driven by said motor; and a protector so disposed at the inner bottom of the casing as to surround the lower end of the revolving shaft in order to prevent the compressor body from striking against the inner wall of the casing, said protector being provided 'with at least one repulsing means for forcing back the revolving shaft making a precessional movement in a reverse direction to the revolution of said shaft along the inner wall of the protector to an original position of the shaft.

2. The compressor according to claim 1 wherein the protector takes a deformed cylindrical shape comprising in cross section two half-circles whose centers are laterally displaced from each other and the repulsing means is formed by connecting the opposite edges of two semicir-' cular members. I V

3. The compressor according to claim 2 wherein the repulsing means has a notch formed at the upper part thereof so as to allow a lubricant to pass therethrough into the protector.

4. The compressor according to claim 1 wherein the protector comprises a spiral piece rolled substantially only once with a clearance allowed between the opposite edges of the joint and the repulsing means is constituted by the inner edge face.

References Cited UNITED STATES PATENTS ROBERT M. WALKER, Primary Examiner US. Cl. X.R. 417-902