Rotary compressor

Abstract

A rotary compressor including a case defining an external appearance of the compressor. A compressing device is arranged inside the case, and a lower cap is fixed to a lower end of the case. The rotary compressor further includes a weld zone to fix the compressing device and lower cap to each other.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 2009-0000712, filed on Jan. 6, 2009 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

1. Field

Embodiments of the present invention relate to a rotary compressor, a compressing device of which is fixedly welded inside a case via an improved configuration.

2. Description of the Related Art

In a general rotary compressor, an eccentric part and a roller are coupled to a rotating shaft that is rotated via electromagnetic interaction between a stator and a rotor. As the eccentric part and roller are eccentrically rotated in a compression chamber defined in a cylinder, compression of refrigerant suctioned into the compression chamber is accomplished. A vane is supported by a vane spring in the compression chamber while being in contact with a surface of the roller, the vane dividing the compression chamber into a low-pressure chamber for suction of refrigerant and a high-pressure chamber for discharge of compressed refrigerant. Such a rotary compressor includes a case provided with a refrigerant suction pipe and a refrigerant discharge pipe, a drive device to generate rotating force, and a compressing device to perform suction and compression of refrigerant.

The drive device includes a stator, a rotor, and a rotating shaft coupled to the rotor and adapted to be rotated along with the rotor. The eccentric part and roller are eccentrically coupled to one end of the rotating shaft thus performing eccentric rotation via rotation of the rotating shaft.

The compressing device includes the compression chamber in which the eccentric rotation of the eccentric part and roller is performed, the cylinder defining the compression chamber, an upper bearing and a lower flange coupled respectively to upper and lower ends of the cylinder to hermetically seal the cylinder, and the vane dividing the compression chamber into the high pressure chamber and the low pressure chamber, the vane being arranged in contact with an outer periphery of the roller and adapted to perform vertical sliding motion based on the eccentric rotation of the roller. The vane is supported by the vane spring in a vane slot defined in one side of the cylinder.

A region of the case in contact with the cylinder is perforated with a plurality of through-holes, and each of the through-holes is formed with a weld zone to integrally couple the cylinder to the case by welding.

In the above-described rotary compressor, to fix the cylinder inside the case, the plurality of through-holes may be perforated in the case and also, an edge of each through-hole may be welded to the cylinder in a radial direction of the case. This may cause the case to be thermally deformed by heat generated during welding, or the cylinder and the upper bearing to be deformed upon receiving the heat transmitted from the case. In addition, welding the edge of the through-hole to the cylinder in the radial direction of the case causes distortion of a gap between the stator and the rotor, resulting in excessive drive load of the compressing device and deteriorating compression efficiency and use life thereof.

SUMMARY

Therefore, it is an aspect of the present invention to provide a rotary compressor, a compressing device of which may be fixed inside a case with a minimized possibility of thermal deformation of a cylinder and an upper bearing, resulting in enhanced efficiency of the compressing device.

Additional aspects of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.

In accordance with one aspect, a rotary compressor includes a case defining an external appearance of the compressor, a compressing device arranged inside the case, a lower cap fixed to a lower end of the case, and a weld zone to fix the compressing device and lower cap to each other.

The weld zone may be formed by at least one reinforcing protrusion extending from the compressing device to the lower cap by a predetermined length.

The weld zone may be formed by at least one supporting protrusion protruding from the lower cap to the compressing device by a predetermined length.

The compressing device may include a cylinder defining a compression chamber for compression of refrigerant gas, and a lower bearing to support the cylinder from the lower side of the cylinder, and the weld zone may be formed in a boundary region between the reinforcing protrusion axially provided at the lower bearing and a through-hole perforated in the lower cap.

The compressing device may include a cylinder defining a compression chamber for compression of refrigerant gas, and a lower bearing to support the cylinder from the lower side of the cylinder, and the weld zone may be formed in a boundary region between a through-hole perforated in the supporting protrusion and the lower bearing.

The reinforcing protrusion may be provided at a peripheral position of a lower bearing to come into close contact with a bottom surface of the lower cap when the lower cap is fixed to the case.

The supporting protrusion may be provided at a peripheral position of the lower cap to come into close contact with a lower bearing when the lower cap is fixed to the case.

The compressing device may further include an upper bearing to support the cylinder from the upper side of the cylinder.

The rotary compressor may further include a stator fixed to the case, a rotor rotatably supported inside the stator, and a rotating shaft press-fitted in the rotor.

In accordance with another aspect of the invention, a rotary compressor includes a case, a cylinder arranged inside the case, a lower bearing closely coupled to a lower end of the cylinder, and a lower cap fixedly welded to the lower bearing for fixing the cylinder in an axial direction.

At least one protrusion may be provided between the lower bearing and the lower cap, to fixedly weld the lower bearing to the lower cap.

The protrusion may be integrally formed with any one of the lower bearing and the lower cap.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a sectional view illustrating a rotary compressor according to an embodiment of the present invention;

FIG. 2 is an exploded partial sectional view of the rotary compressor shown in FIG. 1;

FIG. 3 is a sectional view illustrating a compressing device and a lower cap of the rotary compressor according to the embodiment;

FIG. 4 is an enlarged perspective view of a lower bearing and the lower cap according to the embodiment;

FIG. 5 is a sectional view illustrating a rotary compressor according to another embodiment; and

FIG. 6 is an enlarged perspective view illustrating a lower cap of the rotary compressor shown in FIG. 5.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout.

FIG. 1 is a sectional view illustrating a rotary compressor according to an embodiment, and FIG. 2 is an exploded partial sectional view of the rotary compressor shown in FIG. 1.

As shown in FIGS. 1 and 2, a rotary compressor 10 according to the embodiment includes a case 100 defining an external appearance of the compressor, a drive device 200 to generate drive force, and a compressing device 300 to compress refrigerant gas upon receiving the drive force of the drive device 200. Both the drive device 200 and the compressing device 300 are arranged inside the cylindrical case 100.

The case 100 includes a cylindrical case body 110 in which the drive device 200 and the compressing device 300 are mounted, an upper cap 120, a part of which is fixedly inserted into an upper end opening of the case body 110, and a lower cap 130, a part of which is fixedly inserted into a lower end opening of the case body 110.

The upper cap 120 is subjected to welding in a peripheral direction thereof so as to be coupled to an upper end of the case 100, and the lower cap 130 is subjected to welding in a peripheral direction thereof so as to be coupled to a lower end of the case 100. More particularly, the welding of the upper or lower cap is performed in a peripheral direction such that a fixing weld zone 140 is created in a boundary region between the end of the case 100 and the cap.

A suction pipe 160 is connected to one side of a lower part of the case 100, through which refrigerant gas is fed from an accumulator 150 to the compressing device 300, the accumulator 150 functioning to filter liquid-phase refrigerant. Also, a discharge pipe 170 is connected to an upper part of the case 100, through which the refrigerant gas compressed in the compressing device 300 is discharged. An oil storage space 180 is provided in a bottom region of the case 100, in which a predetermined amount of oil is stored for lubrication and cooling of any frictional member.

The drive device 200 includes a stator 210 fixed to the case 100, a rotor 220 rotatably supported inside the stator 210, and a rotating shaft 230 press-fitted in the rotor 220. With this configuration, if power is applied to the stator 210, the rotor 220 is rotated by electromagnetic force and simultaneously, the rotating shaft 230 integrally press-fitted in the rotor 220 transmits a rotating force of the rotor 220 to the compressing device 300.

The compressing device 300 includes an eccentric part 310 formed near a lower end of the rotating shaft 230, a roller 320 fitted around the eccentric part 310, a cylinder 330 defining a compression chamber 360 in which the roller 320 is received, and an upper bearing 340 and a lower bearing 350 coupled respectively to an upper end and a lower end of the cylinder 330 and adapted to hermetically seal the compression chamber 360 while supporting the rotating shaft 230.

The cylinder 300 and the upper and lower bearings 340 and 350 have bolt fastening holes 300b. As fastening bolts 300a are fastened through the bolt fastening holes 300b, the upper and lower bearings 340 and 350 are brought into close contact with upper and lower surfaces of the cylinder 330, thereby hermetically sealing the compression chamber 360.

The cylinder 330 is provided at one side thereof with a suction port 370, which is connected to the suction pipe 160 connected to the accumulator 150 and is used to feed refrigerant gas into the compression chamber 360, and at the other side thereof with a discharge port (not shown) to guide the refrigerant gas compressed in the compression chamber 360 to the outside of the compression chamber 360.

The upper bearing 340 has a discharge hole 380 formed in communication with the discharge port (not shown) in order to discharge the refrigerant gas guided through the discharge port (not shown) to the outside. A valve device 390 is arranged on the upper bearing 340 at a position immediately above the discharge hole 380 and is used to open or close the discharge hole 380. A mixture of refrigerant and oil is introduced through the suction port 370 and is supplied into the compression chamber 360. Of the mixture, the oil serves to seal the interior of the compression chamber 360. The amount of oil supplied into the compression chamber 360 may be determined to assure appropriate mixing with the refrigerant within a range exerting no degradation in compression efficiency.

FIG. 3 is a sectional view illustrating the compressing device and the lower cap of the rotary compressor according to the embodiment, and FIG. 4 is an enlarged perspective view of the lower bearing and the lower cap according to the embodiment.

As shown in FIGS. 3 and 4, in the rotary compressor 10 according to the embodiment, the compressing device 300 and the lower cap 130 are arranged close to each other, such that a weld zone 400 is created at a contact position therebetween. The weld zone 400 may be created in a boundary region between a reinforcing protrusion 353 extending from the compressing device 300 to the lower cap 130 and a through-hole 130a of the lower cap 130.

The lower bearing 350 of the compressing device 300 includes a bearing body 351 in close contact with the lower surface of the cylinder 330, a rotating shaft inserting portion 352 located at the center of the bearing body 351 and extending perpendicular to the bearing body 351, through which the rotating shaft 230 is inserted, and at least one reinforcing protrusion 353 extending in an axial direction A of the bearing body 351.

The lower cap 130 includes a bottom portion 131 arranged to close the lower end opening of the case 100, and a peripheral portion 132 extending upward from a peripheral edge of the bottom portion 131. The boundary region between the peripheral portion 132 of the lower cap 130 and the case 100 is subjected to welding in the peripheral direction, to create the fixing weld zone 140 for fixedly welding the lower cap 130 to the case 100.

Also, the weld zone 400 is created in the bottom portion 131 via the through-hole 130a, i.e. in the boundary region between the through-hole 130a and the lower bearing 350, thereby fixedly welding the lower bearing 350 to the lower cap 130. In this way, the compressing device 300 is fixedly welded to the lower cap 130 located therebelow to thereby be fixed inside the case 100. More particularly, as the cylinder 330 is fixedly welded in the axial direction A to the lower cap 130 via the lower bearing 350 that supports the cylinder 300, the cylinder 330 may be fixed inside the case 100 without unwanted movement:

The reinforcing protrusion 353 extends downward from the lower bearing 350 in the axial direction A, to allow the lower bearing 350 to be welded to the lower cap 130. In the embodiment as shown in FIG. 2, three cylindrical reinforcing protrusions 353 may be arranged on peripheral positions of a lower surface of the bearing body 351 to extend parallel to the rotating shaft inserting portion 352 in the axial direction A. Of course, the reinforcing protrusions 353 are simply provided for the purpose of connecting the compressing device 300 to the lower cap 130 for welding therebetween and therefore, the reinforcing protrusions 353 may be replaced by various numbers and shapes of substitutions between the lower bearing 350 and the lower cap 130.

Now, an assembly method of the rotary compressor according to the embodiment will be described.

First, the stator 210 of the drive device 200, the compressing device 300, and the rotor 220 of the drive device 200 are sequentially press-fitted into the case 100. Then, in a state wherein a gap gauge (not shown) is inserted into a gap between the stator 210 and the rotor 220, a height of the rotary compressor 10 is aligned.

Next, the peripheral portion 132 of the lower cap 130 is inserted into the lower end opening of the case 100 and is fixedly welded to the case 100. Then, the bottom portion 131 of the lower cap 130 is welded to the compressing device 300 in the axial direction A, to fix the compressing device 300 inside the case 100.

After removing the gap gauge (not shown) between the stator 210 and the rotor 220, the upper cap 120 is welded to the case 100, completing the assembly of the rotary compressor 10.

Hereinafter, operation of the rotary compressor according to the embodiment will be described.

In the rotary compressor 10 according to the embodiment, to fix the compressing device 300 inside the case 100, the compressing device 300 is welded in the axial direction A of the case 100, rather than being welded in a radial direction of the case 100. Therefore, interior elements, such as, e.g., the cylinder 330 and the rotating shaft 230, may be fixed at positions assuring smooth motions thereof.

Further, owing to the weld zone 400 for fixation of the compressing device 300 being provided in the boundary region between the compressing device 300 and the lower cap 130, neither the cylinder 330 nor the upper bearing 340 are thermally deformed by heat generated during welding.

Furthermore, in a state wherein the gap gauge (not shown) is inserted between the stator 210 and the rotor 220 of the drive device 200 to assure a desired space, the lower cap 130 is first welded to the case 100 and thereafter, is welded to the compressing device 300. This assures the welding of the compressing device 300 to have only minimal effect on a gap of the rotary compressor 10, preventing deterioration in performance of the rotary compressor 10 caused when the stator 210 and rotor 220 of the rotary compressor 10 are incorrectly aligned.

Next, another embodiment will be described with reference to FIGS. 5 and 6. The same or similar elements as those of the previous embodiment are denoted by the same reference numerals, and a description thereof will be omitted. FIG. 5 is a sectional view illustrating a rotary compressor according to another embodiment, and FIG. 6 is an enlarged perspective view illustrating a lower cap of the rotary compressor shown in FIG. 5.

A rotary compressor 10′ according to the present embodiment includes the case 100 defining an external appearance of the compressor 10′, a compressing device 300′ arranged inside the case 100, a lower cap 130′ coupled to the lower end opening of the case 100, and a weld zone 400′ to fix the compressing device 300 and lower cap 130′ to each other.

The weld zone 400′ according to the present embodiment may be created in a boundary region between a supporting protrusion 133′ extending from the lower cap 130′ to the compressing device 300′ and the compressing device 300′.

The lower cap 130′ includes a bottom portion 131′ arranged to close the lower end opening of the case 100, and a peripheral portion 132′ extending upward from a peripheral edge of the bottom portion 131′. At least one supporting protrusion 133′ may protrude upward from the bottom portion 131′ and in turn, a through-hole 130a′ may be perforated throughout the supporting protrusion 133′.

A certain number of supporting protrusions 133′ may be arranged on peripheral positions of the bottom portion 131′. Of course, similar to the above-described reinforcing protrusions 353, the number and shape of the supporting protrusions 133′ may be determined in various manners so long as the supporting protrusions 133′ provide satisfactory connection between the compressing device 300′ and the lower cap 130′. That is, the shape and size of the supporting protrusions 133′ may be determined in such a manner that the supporting protrusions 133′ formed on the bottom portion 131′ come into close contact with the compressing device 300′ when the lower cap 130′ is inserted into the lower end opening of the case 100, thereby being fixedly welded to the compressing device 300′ via the through-holes 130a′.

Accordingly, the compressing device 300′ is fixedly welded to the lower cap 130′ located therebelow to thereby be fixed inside the case 100. More particularly, as the cylinder 330 is fixedly welded in the axial direction A to the lower cap 130′ via a lower bearing 350′ that supports the cylinder 300, the cylinder 330 may be fixed inside the case 100 without unwanted movement.

As is apparent from the above description, a rotary compressor according to the embodiments is basically configured in such a manner that a compressing device is axially welded to a lower cap, preventing thermal deformation of interior elements while assuring that the interior elements are coupled at accurate positions for smooth motion thereof.

Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Claims

1. A rotary compressor comprising:

a case defining an external appearance of the compressor;

a compressing device arranged inside the case;

a lower cap fixed to a lower end of the case; and

a weld zone to fix the compressing device and lower cap to each other.

2. The compressor according to claim 1, wherein the weld zone is formed by at least one reinforcing protrusion extending from the compressing device to the lower cap by a predetermined length.

3. The compressor according to claim 1, wherein the weld zone is formed by at least one supporting protrusion protruding from the lower cap to the compressing device by a predetermined length.

4. The compressor according to claim 2, wherein the compressing device includes a cylinder defining a compression chamber for compression of refrigerant gas, and a lower bearing to support the cylinder from the lower side of the cylinder, and wherein the weld zone is formed in a boundary region between the reinforcing protrusion axially provided at the lower bearing and a through-hole perforated in the lower cap.

5. The compressor according to claim 3, wherein the compressing device includes a cylinder defining a compression chamber for compression of refrigerant gas, and a lower bearing to support the cylinder from the lower side of the cylinder, and

wherein the weld zone is formed in a boundary region between a through-hole perforated in the supporting protrusion and the lower bearing.

6. The compressor according to claim 2, wherein the reinforcing protrusion is provided at a peripheral position of a lower bearing to come into close contact with a bottom surface of the lower cap when the lower cap is fixed to the case.

7. The compressor according to claim 3, wherein the supporting protrusion is provided at a peripheral position of the lower cap to come into close contact with a lower bearing when the lower cap is fixed to the case.

8. The compressor according to claim 4 or 5, wherein the compressing device further includes an upper bearing to support the cylinder from the upper side of the cylinder.

9. The compressor according to claim 8, further comprising:

a stator fixed to the case;

a rotor rotatably supported inside the stator; and

a rotating shaft press-fitted in the rotor.

10. A rotary compressor comprising:

a case;

a cylinder arranged inside the case;

a lower bearing closely coupled to a lower end of the cylinder; and

a lower cap fixedly welded to the lower bearing for fixing the cylinder in an axial direction.

11. The compressor according to claim 10, wherein at least one protrusion is provided between the lower bearing and the lower cap, to fixedly weld the lower bearing to the lower cap.

12. The compressor according to claim 10, wherein the protrusion is integrally formed with any one of the lower bearing and the lower cap.