Hermetic compressor

Abstract: This hermetic compressor includes a regulation mechanism, which is arranged between a lower washer and an upper end face of a bearing, for regulating a movable distance in a thrust direction of the lower washer so that the movable distance can be shorter than clearance between an inner diameter of the lower washer and an outer diameter of a main shaft portion. It is possible to prevent the inner diameter of the lower washer from coming into contact with the outer diameter of the main shaft portion by this regulation mechanism. (end of abstract)

Hermetic compressor description/claims

Brief Patent Description

Full Patent Description

Patent Application Claims

TECHNICAL FIELD

The present invention relates to a hermetic compressor mainly used for a refrigerator for domestic use.

BACKGROUND ART

In a conventional hermetic compressor in which a thrust ball bearing is employed for enhancing the efficiency, washers arranged on the upper and lower sides of the thrust ball bearing can be freely rotated round the shaft and the bearing. This prior art is disclosed, for example, in the official gazette of Japanese Patent Unexamined Publication No. 61-53474.

Referring to the drawings, the above conventional hermetic compressor will be explained below.

FIG. 18 is a longitudinal sectional view of the conventional hermetic compressor and FIG. 19 is an enlarged sectional view showing a primary portion of the conventional hermetic compressor.

In FIGS. 18 and 19, refrigerant 3002 is charged into hermetic container 3001. Further, refrigerating machine oil 3003 is stored in hermetic container 3001.

Electrically driving element 3011 includes: stator 3012 connected to an external electric power source (not shown): and rotor 3013 arranged inside stator 3012, forming a predetermined gap between rotor 3013 and stator 3012.

Compression element 3021 includes: shaft 3022; cylinder block 3023; bearing 3024; piston 3025 reciprocating in compression chamber 3023a; connecting portion 3026; and thrust ball bearing 3031. Shaft 3022 includes: main shaft portion 3022a; and eccentric shaft portion 3022c. Cylinder block 3023 is fixed under stator 3012 and forms compression chamber 3023a. Bearing 3024 supports shaft 3022 provided in cylinder block 3023. Piston 3025 is reciprocated in compression chamber 3023a. Connecting portion 3026 connects piston 3025 with eccentric shaft portion 3022c. Thrust ball bearing 3031 is arranged between rotor 3013 and an upper end face of bearing 3024. Compression element 3021 composes a reciprocating type compression mechanism.

Thrust ball bearing 3031 includes: a plurality of balls 3032; holder portion 3033 to hold balls 3032; upper washer 3034 arranged above balls 3032; and lower washer 3035 arranged below balls 3032.

Operation of the hermetic compressor composed as described above will be explained as follows.

When stator 3012 is energized by an external electric power source, rotor 3013 is rotated together with shaft 3022. Due to the foregoing, an eccentric motion is conducted by eccentric shaft portion 3022c. Therefore, eccentric shaft portion 3022c reciprocates piston 3025 through connecting portion 3026 in compression chamber 3023a. Accordingly, a predetermined compressive motion to compress suction gas is conducted.

Thrust ball bearing 3031 supports a vertical load generated by the dead weights of rotor 3013 and shaft 3022. Therefore, it is possible to reduce a frictional force generated between rotor 3013 and bearing 3024. Accordingly, an intensity of electric power to be inputted into the hermetic compressor can be decreased and the efficiency can be enhanced.

However, in the above conventional structure, in order to make it easy to assemble the components, thrust ball bearing 3031 is only put on an upper end face of bearing 3024, that is, thrust ball bearing 3031 is arranged without being fixed. Accordingly, there is a possibility that lower washer 3035 is arranged being shifted at the time of assembling. Further, there is a possibility that lower washer 3035 is shifted by a shock while the device is being conveyed and an inner diameter of lower washer 3035 comes into contact with an outer diameter of main shaft portion 3022 which is being rotated.

Concerning lower washer 3035, since a lower face of lower washer 3035 is closely contacted with an upper end face of bearing 3024 through viscosity of refrigerating machine oil 3003, lower washer 3035 is not rotated together with balls 3032 and holder portion 3033. Therefore, when an inner diameter of lower washer 3035 comes into contact with an outer diameter of main shaft portion 3022a which is rotating, abrasion powder is generated. The thus generated abrasion powder spreads to each sliding portion of the hermetic compressor and causes abrasion.

DISCLOSURE OF THE INVENTION

A hermetic compressor comprises:

an electrically driving element having stator and a rotor, the electrically driving element being accommodated in a hermetic container; and

a compression element driven by the electrically driving element, the compression element being accommodated in the hermetic container,

the compression element comprising: