US20110135523A1

US20110135523A1 - Sealed compressor with motor standard spacer providing bearing mount

Info

Publication number: US20110135523A1
Application number: US12/633,839
Authority: US
Inventors: John R. Williams; Tracy L. Milliff; Gene M. Fields; Zili Sun; Edward A. Tomayko; Gregory W. Hahn; Thomas R. Barito; Carlos Zamudio; Joe T. Hill
Original assignee: Individual
Current assignee: Danfoss Scroll Technologies LLC
Priority date: 2009-12-09
Filing date: 2009-12-09
Publication date: 2011-06-09

Abstract

A spacer is positioned between an outer periphery of a motor stator, and the inner periphery of a center shell for a sealed compressor. The spacer allows a relatively small diameter motor to be used in a relatively large diameter center shell. The spacer includes a bearing mount in a lower plate, and a plurality of axially extending fingers positioned between the stator and the center shell. The spacer also includes a stop for proper positioning of the stator within the center shell.

Description

BACKGROUND OF THE INVENTION

This application relates to a sealed compressor, wherein a spacer is positioned between a motor stator and an internal wall of a cylindrical shell, such that smaller diameter motors can be utilized. The spacer provides a motor stop surface and mounts a bearing.
Sealed compressors are known, and typically include an electric motor driving a shaft to drive a pump unit. One relatively popular type of sealed compressor is a scroll compressor.
It is known to seal a housing for the compressor such that refrigerant can circulate within the compressor housing. As an example, suction refrigerant on its way to the compressor pump unit is often circulated over the cooled motor. This requires the housing shell to be hermetically sealed. Typically, a cylindrical shell is attached to end caps at each axial end.
The cylindrical shell must have a particular diameter for a variety of reasons. One reason might be the size of the compressor pump unit. This sometimes requires an undesirably large diameter motor.
Thus, the size of the compressor shell has limited the available motors, and often required unnecessarily large electric motors. It has been proposed in the prior art to put a cylindrical ring as a spacer between an outer periphery of the motor stator and an inner periphery of the cylindrical shell, to allow the use of a smaller motor. However, the proposed structure is generally a cylindrical ring, and would raise assembly issues.

SUMMARY OF THE INVENTION

In a disclosed embodiment of this invention, a spacer is positioned between a stator of an electric motor, and an interior wall of a center shell. The spacer allows a motor with a smaller outer diameter than the inner diameter of the center shell, to be secured within the center shell. The spacer includes a relatively flat plate at an end of the sealed compressor remote from a compressor pump unit, and having a bearing mount. In this manner, a bearing for supporting a shaft driven by an electric motor can be mounted into the spacer, which simplifies positioning and centering of the motor and the shaft relative to the center shell. In other features, the spacer is formed of a plurality of fingers extending axially from the plate, and which are positioned between the outer periphery of the motor and the center shell. Also, a stop is formed on the spacer to provide an axial stop for the motor stator as it moves within the center shell.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of the sealed compressor incorporating the present invention.

FIG. 2 is a perspective view of a spacer according to an embodiment of this invention.

FIG. 3 is an assembly step according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a sealed compressor 20 incorporating a compressor pump unit 22, and an end cap 24 secured to a cylindrical center shell 26. A lower end cap 28 is secured to an opposed end of the center shell 26. The center shell has an inner diameter which is defined in part by the size of the compressor pump unit 22. A motor has a stator 30 with a smaller outer diameter than the inner diameter of the shell 26. A spacer 38 is positioned between an inner periphery of the center shell 26 and an outer periphery of the stator 30. The stator 30 drives a rotor 32 which in turn drives a shaft 34. As shown in FIG. 1, the shaft 34 is supported within a bearing 36. The bearing 36 is supported in a plate-like lower portion 42 of the spacer 38. A bearing member 54 is secured within an opening 44. A plurality of fingers 41 extend axially towards the pump unit 22 from the plate 42, and are positioned intermediate the stator 30 and the center shell 26. As can be seen, a stop 40 provides a stop surface to properly axially position the stator 30.
As shown in FIG. 2, the fingers 41 include radially outwardly extending portions 57 and radially inwardly extending portions 59. As can be appreciated, radially outwardly extending portions 57 abut the inner periphery of the center shell 26 and radially inwardly extending portions 59 abut the outer periphery of the stator 30.
As also shown, the plate 42 has a downwardly extending bearing mount 44 for receiving the bearing 54. Ribs 43 are formed on the plate to provide a strong construction.
As shown in FIG. 3, the center shell 26 may be mounted downwardly over the fingers 41, with the fingers 41 having a chamfered top end 80 to facilitate the downward movement. The center shell 26 moves downwardly towards the lower end cap 28 to a position 100. As can be appreciated, the stator can then be moved into the legs 41, and will be secured by the legs 41, and supported on the pump 40.
The present invention thus provides a spacer that not only secures a motor stator within a center shell, but also properly positions a stator, and further provides a bearing mount for the shaft.
A related way of adapting a small frame motor to a larger diameter shell is disclosed in co-pending U.S. patent application Ser. No. ______, filed on even date herewith, and entitled “Deformed Shell for Holding Motor Stator in a Compressor Shell.”
Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.

Claims

1. A sealed compressor comprising:

a center shell having an inner periphery of a first diameter;

at least one end cap secured to said center shell;

a compressor pump unit mounted within said center shell;

an electric motor having a stator with an outer periphery of a second diameter, said second diameter being smaller than said first diameter, and said stator driving a rotor, said rotor driving a rotating shaft, and said rotating shaft driving said compressor pump unit; and

a spacer positioned between said outer periphery of said stator and said inner periphery of said center shell, said spacer having a lower plate, said lower plate including a bearing mount, said bearing mount receiving a bearing, and said rotating shaft mounted within said bearing.

2. The sealed compressor as set forth in claim 1, wherein said spacer further including a plurality of circumferentially spaced fingers extending from said lower plate, and said fingers being positioned between said outer periphery of said stator and said inner periphery of said shell.

3. The sealed compressor a set forth in claim 2, wherein an upper extent of said fingers includes a chamfer to facilitate movement of said center shell over said fingers.

4. The sealed compressor as set forth in claim 1, wherein said spacer including a stop, said stator being positioned on said stop, with said stop properly positioning said stator along an axis of rotation.

5. The sealed compressor as set forth in claim 1, wherein said lower plate includes a plurality of ribs to provide rigidity.

6. A sealed compressor comprising:

a center shell having an inner periphery of a first diameter;

at least one end cap secured to said center shell;

a compressor pump unit mounted within said center shell;

a spacer positioned between said outer periphery of said stator and said inner periphery of said center shell, said spacer including a stop, said stator being positioned on said stop, with said stop properly positioning said stator along an axis of rotation of said shaft.

7. The sealed compressor as set forth in claim 6, wherein said spacer further including a plurality of circumferentially spaced fingers extending from a plate, said plate including a bearing mount, and said fingers being positioned between said outer periphery of said stator and said inner periphery of said shell.

8. The sealed compressor as set forth in claim 7, wherein said plate includes a plurality of ribs to provide rigidity.

10. The sealed compressor a set forth in claim 7, wherein an upper extent of said fingers includes a chamfer to facilitate movement of said center shell over said fingers.