US2468948A

US2468948A - Sealed motor-compressor unit

Info

Publication number: US2468948A
Application number: US596287A
Authority: US
Inventors: Rolf M Smith
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1945-05-28
Filing date: 1945-05-28
Publication date: 1949-05-03
Anticipated expiration: 1966-05-03

Description

y 1949- R. M. SMITH 2,468,948

v SEALED MOTOR-COMPRESSORUNIT F iled May 28, 1945' 2 Sheets-Sheet 1 l4 4 a ID-IVENTOR. I BYpQA Mm 1%,

May 3, 1949. R. M. SMITH 2,468,948

SEALED MOTOR- COMPRES SOR UNIT Filed May 28, 1945 2 sheets-sheet 2 WMINVENTOR.

BY 7a.

Patented May 3, 1949 amass SEALED MOTOR-COLIPRESSOB UNIT Rolf M; Smith, Dayton, Ohio, assignor to General'MotoH Corporation, Dayton, Ohio, a cor- 1 *poration of Delaware Application-May 2a, 1945, Serial No. 596,28:

ll'Claims. (01.- 230-139) This invention relates to refrigerating apparatus and more particularly to an improved motorv compressor construction.

It is an object of this invention to reduce the cost of a motor-compressor unit by simplifying the manufacture and assembly of the various parts which make up the unit.

It is another object of this invention to increase the operating efllciency of a motor-compressor unit. I

Another object of this invention is to facilitate accurate alignment of the parts during assembly.

Still another object of this invention is to provide a practical unloading arrangement which eliminates the need for a large number of moving parts.

A further object of thisinvention is to provide an improved lubricant distributing system in which lubricant under pressure is used for loading the compressor.

Still another object of this invention is to provide an improved 4-vane rotor construction in which the rotor is made separate from the shaft and in which a portic .1 of the rotor next to the shaft is cut away for the multiple purpose of reducing friction, facilitating the distribution of lubricant to the parts, and serving as a means for equalizing the pressure at the inner ends of the vanes.

Further objects and advantages of the present invention will be apparent from the following description, referencebeing had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a vertical sectional view of a motorcompressor unit embodying my invention;

Fig. 2 is a horizontal sectional view taken. substantially on line 2-2 of Fig. 1; and

Fig. 3 is a view taken substantially on line 3-3 of Fig. 2.

Referring now to the drawing wherein I have shown a preferred embodiment of my invention, reference numeral i designates a substantially cup-shaped sheet metal casing which is adapted to be closed at its upper end by means of a cap I2 which is bolted or otherwise secured to the casing III. A compressor mounting block I4 is welded or otherwise secured in place within the lower portion of the cup-shaped casing Ill. The lower portion of the block l4 projects outside of the casing I3 and is provided with a horizontal nassage l6 which communicates with the suction l he A motor stator 23 is secured to the'inner wall of the casing III, as shown. A-motor rotor'; 22, I carried by the upper end of the motor-compressor shaft 24, is disposed in alignment with the motor stator and serves to impart rotation to "the shaft 24 in accordance with well-known practice.

The bottom end of the shaft 24 is journalled in the bearing block 23 which also serves as the lower end plate for the main compressor cylinder 23. The central portion of the shaft 24' is journalled in the upper end plate 33 ofthe compressor. The

end plates

26 and 30 together with the main cylinder 23 are held in place by means.

of a plurality of bolts 32 which securely bolt these elements to themounting block i4, as shown.

It will be noted that the outer circumference of the

elements

26, 28 and 331s slightly less than the inner circumference of the motor stator whereby it is possible to assemble the compressor down through the motor stator opening after the motor stator has been mounted in place within the casing It. By virtue of this construction and arrangement, it is possible to accurately align the shaft bearings with the internal surface of the motor stator 23 and to remove, if necessary, the compressor from the casing without removing the motor stator. The shape of the shaft 24 is such that it and the motor rotor 22 which is secured thereto may be inserted or removed after the compressor parts have been bolted in place on the mounting block l4. By machining the upper surface of the block l4 perpendicular to the motor stator mounting surface, it is possible to accurately align the critical parts in a [very simple manner.

After machining both the upper surface of the means of a split positioning ring 33 which snugly fits within the recess 35 provided in the mounting block l4, as shown. The recess 35 is made concentric to the inner surface of the casing i0 which supports the motor stator 20. The end plate 26 is provided with a circular groove 31 for the reception of the split ring 33. The groove 31 is made concentric with the bearing aperture in the plate 26. By virtue of the above described arrangement, the split ring 33 serves to centrally locate the compressor mechanism. By. making the split ring 33 removable it is possible to lap the meeting surfaces of the plate 26 and the mountaaeaeea ing block It without interference from any positioning lugs or the like.

The rotor 34 is of the i-vane type and is arranged to be operated by the shaft 26. In order to facilitate assembly and in order to reduce the cost of the unit in general, the rotor 34% is made separate from the; shaft 2% but is keyed or other wise fastened to the shaft 25 so as to rotate therewith during operation of the compressor. For

purposes of illustration, 1 have shown a key 25 (Fig. 2) for drivingly connecting the shaft Ed and the rotor A substantially conical cavity is formed at each end of the rotor as best shown in Fig. 1. One purpose of this construction is to reduce friction between the ends of the rotor 35 and the end plates 25 and 3B. This reduction in friction is partly accounted for by the reduction in the area of contact between the ends of the rotor and the end plates and is further accounted for by the fact that the shorter contact between the rotor and the shaft makes it possible for the ends of the rotor to line up better with the end plates. It has been discovered that the rate of wear between the ends of the rotor and the end plates may be materially reduced by cutting away the rotor in the above described manner.

As best shown in Fig. 2, the rotor M is provided with four slots 36 within which the vanes 38 are slidably mounted. The vanes 38 are provided with vane shoes it which are rockably held in place relative to the vanes in the manner more fully explained in the David W. Meg'eber patent application S. N. 596,285, filed May 28, 1945, now Patent No. 2,458,620, issued January 11, 1949, and entitled Refrigerating apparatus." The inner end of each vane is cut away as indicated at 2 so as to provide a relief passage for lubricant. The cut away portion d2 thus serves as a means of communication between the conical cavities 2? provided at the opposite ends of the rotor is as clearly shown in Fig. 1. The vanes 38 will move inwardly and unload the compressor when the compressor runs slow or stops running as the only forces holding the vanes outwardly are the centrifugal force and the force of the oil pressure I a may be varied somewhat without departing from the spirit of my invention.

The bottom of the cup-shaped casing it! serves two separate oil feed grooves it and it which are back of the vanes and these forces are overcome by the force of the compressed gas acting against the outer ends of the vanes at slow speeds.

directed to the inlet valve cavity 35 located in the mounting block it. As shown in Figs. 1 and 3, the inlet valve comprises a valve plate which has spacing lugs 52 serving to centrally locate the. valve plate in spaced relationship to the side walls of the narrow portion of the cavity 35. A valve seat 56 which is preferably made of suitable gasket material is provided as shown in Fig. 1 for engagement by the valve plate 50 when the valve is in the closed or down position. The valve plate 58 moves upwardly off from the seat 56 during operation of the compressor and is limited in its upward movement by the bottom side of the end thrust bearing assembly Ell. The assembly 60 is secured to the compressor end plate 26 by means of one or more'screws 62 and projects down into the recess 35, as shown in Fig. l. The end plate 25 is provided with a gas passage t l which communicates with the main inlet port til in the side wall of the cylinder 28. The main cylinder 28 is provided with an outlet port iii in one wall thereof as best shown in Fig. 2. The construction and arrangement of the inlet and outlet ports shown used for pumping oil from the oil sum into the various bearing surfaces. Thus, the upper end of the oil feed groove it discharges lubricant into the conical recess 2? formed in the lower end of the rotor 3% whereas, the oil feed groove lb feeds lubricant into a longitudinally extending lubri cant passage be provided in the shaft 2%. The passage 8?; may be formed by drilling a hole up= wardly from the lower end of the shaft and then plugging the lower end or inlet of the hole. A radial hole 82 leading from the lower end of the passage 8b serves to convey lubricant from the upper end of the oil feed groove "it into the passage Bll whereas, a radial hole 65 conveys lubricant from the upper end of the passage til into an oil feed groove 86 which serves to supply oil to the upper bearing end and which then discharges the excess oil into the conical cavity 2'5 at the upper end of the rotor., By virtue of the above described arrangement, it is obvious that oil is fed into the space behind the vanes from both ends of the rotor. A lubricant outlet passage lid is provided in the upper end plate 30 for discharging the excess lubricant back into the main lubricant sump. The size of the outlet is such that the lubricant in the space behind the vanes is maintained under pressure.

In order to simplify this disclosure, I have not shown gasket means for sealing the joints between the various metallic surfaces whereas, it is within the purview of this invention to use such gasket means wherever desired.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, as may come within the scope of the claims which follow.

What is claimed is as follows:

1. In a sealed motor-compressor unit, a substantially cup-shaped casing, a motor including a motor rotor and a motor stator, said motor stator being supported by said casing and provided with a central opening for the reception of said motor rotor, a rotary compressor driven by said motor and having an end surface, compressor mounting block means carried by the bottom wall of said casing and providing a compressor engaging surface, said mounting block means having a recess in its upper surface, a removable ring-like element carried within said recess and having a portion projecting upwardly beyond said compressor engaging surface, a circular groove provided in the end surface of said compressor for engagement with said ring to properly position said compressor upon said mounting block means, said ring being arranged in axial alignment with the central opening of said motor stator and serving to align said compressor with said central opening, and means for rigidly securing said compressor to said mounting block means.

2. In a sealed motor-compressor unit. a casing, a motor stator disposed within said casing, compressor mounting block means secured to said casing and having a flat compressor mounting surface, a compressor assembly mounted on said mounting block means, said mounting block means having a recess in its upper face, said compressor assembly comprising a cylindermember having an inlet and an outlet for refrigerant fluid to be compressed therein, a pair of end plates for closing the ends of said cylinder and having bearing apertures therein, a motor-compressor shaft journalled in said bearing apertures, an end thrust bearing assembly secured to the bottom side of the lower end plate and projecting into the recess in the upper surface of said mounting block, and an inlet valve disposed in said recess including a valve plate, said end thrust bearing assembly serving as a means for limiting upward movement of said valve plate, said unit having a refrigerant inlet port communicating with said recess and an outlet port adjacent the upper end of said impeller. a third communicating with said recess and with the inlet of said compressor cylinder member.

3. In a sealed motor-compressor unit; a cupshaped casing formed of stamped sheet metal material; a motor including a motor stator supported by said casing; compressor mounting means secured to the bottom wall of said casing; a compressor assembly comprising a cylinder, top and bottom end plates for said cylinder having shaft bearing apertures therein, a shaft driven by said motor, an impeller between said end plates driven by said shaft, a longitudinally extending oil feed passage provided in said shaft, said compressor assembly and said compressor mounting means having formed therebetween a lubricant cavity, means for feeding lubricant to I said cavity, spiral oil feed grooves provided on said shaft, one of said grooves having its inlet in said cavity-and having its outlet communicating with the lower end of said oil feed passage, a second oil feed groove on said shaft having its inlet end communicating with the upper end of said oil feedpassage and having its lower end discharging lubricant adjacent the'upper end of said impeller, a third oil feed groove having its inlet in said lubricant cavity and having its outlet adjacent the lower end of said impeller.

4. In a sealed motor-compressor unit; a cupshaped casing formed of stamped sheet metal material; a motor including a motor statorsupported by said casing; compressor mounting means secured to the bottom wall of said casing; a compressor assembly comprising a cylinder forming a working chamber and provided with communicating inlet and outlet ports, top and bottom end plates for said cylinder having shaft bearing apertures therein, a shaft driven by said motor, an impeller between said end plates driven by said shaft and arranged to draw fluid in through said inlet port, compress the same'and discharge it through said outlet port, a'longitudinally extending oil feed passage provided in said shaft, said compressor assembly and said compressor mounting means having formed therebetween a lubricant cavity, means for feeding lubricant to said cavity, spiral oil feed grooves provided on said shaft, one of said grooves having its inlet in said cavity and having its outlet communicating with the lower end of said oil feed passage, a second oil feed groove on said shaft having its inlet end communicating with the upper end of said oil feed passage and having its lower end discharging lubricant cavity and having its outlet adjacent the lower end of said impeller, said impeller having vane slots formed in its outer periphery, .and vanes disposed in said slots, said impeller having lubrl-,

cant chambers adjacent its ends connecting said vane slots.

5. In a sealed motor-compressor unit; a cupshaped casing formed of stamped sheet metal material;-a motor including a motor stator supported by said casing; compressor mountin means secured to the bottom wall of said casing; a compressor assembly comprising a cylinder forming a working chamber and provided with communicating inlet and outlet ports, top and bottom end plates for said cylinder having-shaft bearing apertures therein, a shaft driven by said motor, an impeller between said end plates driven by said shaft and arranged to draw fluid in through said inlet port, compress the same and discharge it through said outlet port a longitudinally extending oil feed passage provided in said shaft, said compressor assembly and said compressor mounting means having formed therebetween a lubricant cavity, means for feeding lubricant to said cavity, spiral oil feed grooves provided on said shaft, one of said grooves having its inlet in said cavity and having its outlet communictaing with the lower end of said oil feed passage, a second oil feed groove on said shaft having its inlet end communicating with the upper end of said oil feed passage and having its lower end discharging lubricant adjacent the upper end of said impeller, a third oil feed groove having its inlet'in said lubricant cavity and having its outlet adjacent the lower end of said impeller, said impeller having vane slots formed in its outer periphery, and vanes disposed in said slots, said impeller having lubricant chambers adjacent its ends connecting said vane slots, the upper impeller chamber receiving lubricant from said second oil feed groove and a lower impeller chamber receiving lubricant from said third oil feed groove, said vanes having a cavity in their inner ends communicating with each of said impeller lubricant receiving chambers.

6. A compressor assembly comprising in combination, means forming a main fluid working cylinder having an inlet and an outlet communicating T therewith, top and bottom end plates for' said cylinder having shaft bearing apertures therein, a shaft supported by said shaft bearing apertures, an impeller between said end plates driven by said shaft and arranged to draw fluid -in through said inlet, compress the same and discharge it through said outlet, said impeller having vane slots provided in its outer periphery, vanes disposed within said vane slots, the ends of said impeller having recesses formed centrally thereof, the outer portions of said recesses intersecting said vane slots, said recesses extending inwardly far enough so that each recess extends substantially one-third of the way through said impeller, the inner ends of said vanes having lubricant channels formed therein for the free passage of lubricant from said vane slots into said recesses and from one recess into the other, said channels being disposed inwardly from the side walls of said vanes so as not to reduce the sealing surface of the side walls of the vane.

7. A compressor assembly comprising in combination, means forming a main fluid working cylinder having an inlet and an outlet communiaeeaoas substantially one-third of the Way through said impeller.

8. In a motor-compressor unit, a casing'having portions formed of stamped sheet metal material, a rotor stator disposed within said casing, compressor mounting block means forming a portion. of said casing and having a fiat compressor mounting surface, a compressor assembly mount ed on said mounting block means, said mounting block means having a recess in its upper surface, said compressor assembly comprising a cylinder member provided with port means, a pair of end plates for closing the ends of said cylinder and having bearing apertures therein, a motor-compressor shaft journaled in said bearing apertures, an end thrust bearing assembly secured to the bottom side of the lower end plate and projecting into the recess in the upper surface of said mounting block, an inlet valve disposed in said recess 9. A motor-compressor unit comprising in combination, a casing, a compressor mounting block secured to said casin with a portion thereof projecting through the bottom wall of. the casing, a motor stator carrier directly by said casing adjacent the upper portion thereof, compressor mechanism supported on said mounting block, said compressor mechanism comprising a pair of apertured end plates and a main cylinder mounted between said plates, a compressor rotor disposed within said cylinder, said compressor rotor having a central aperture, a shaft journaled in the aperture of said end plates and having a portion arranged in driving engagement with said compressor rotor, a motor rotor within said motor stator and secured to said shaft, said cylinder having a refrigerant inlet port and a refrigerant outlet port, said compressor rotor having vane slots formed in its outer periphery, vanes disposed withinsaid slots, said compressor mechanism being adapted to draw refrigerant into said cylinder through said inlet port, compress the refrigerant and discharge the same through said outlet port, said compressor rotor having a lubricant chamber adjacent each of its ends communicating with said vane slots, said compressor mechanism and said compressor mounting block having formed therebetween a lubricant cavity, means for supplying lubricant pressor mounting block means forming a wall to said cavity, a longitudinally extending oil feed passage provided in said shaft, spiral oil feed d grooves provided on said shaft, one of said grooves being provided on the lower end portion of said shaft with its imet in said cavity and its outlet communicating with the lower end of said oil feed passage for circulating oil thereto, a second oil feed groove on an upper portion or said shaft with its inlet communicating with and adapted to receive oil from the upper end of said oil feed passage and its outlet adjacent the upper end of said compressor rotor for dischargin oil into the lubricant chamber therein, and a third oil feed groove provided on the lower end portion of said shaft with its inlet in said cavity and its outlet adjacent the lower end of said compressor rotor for circulating oil to the lubricant chamber therein.

10. The combination defined in claim 9 where in the inner end of said vanes have a lubricant channel provided therein communicating with each of the lubricant chambers of said compres sor rotor for the free passage of oil therebetween.

11. In a motor-compressor unit, a casing, a rotor stator disposed within. said casing, comportion of said casing and having a flat compressor mounting surface, a compressor mechanism mounted on said mounting block means, said compressor mechanism comprising a cylinder member provided with inlet and outlet port means for refrigerant to be compressed therein, said mounting block means having a recess in said surface thereof, upper and lower end plates for closing the ends of said cylinder and each having bearing apertures therein, a motor-compressor shaft journaled in said bearing apertures, an end thrust bearing assembly secured to the bottom-side of said lower end plate and projecting into the recess in said surface of said mount-= ing block means, means for introducing refrigerant vapor to be compressed by said compressing mechanism into said recess in thermal exchange relationship with said bearing assembly, means for conveying oil to the upper-side of said and thrust bearing, and means for circulating oil from the upper-side of said end thrust bearing to the bearing apertures in said end plates.

ROLF, M. SMITH.

The following references are of record in the file of this patent:

UNTIED STATES PATENTS Number Name Date 1,635,006 Oliver July 5, 1927 1,878,744 Wilson Sept. 20, 1932 1,967,034 Lipman July 17, 1934 1,992,348 Belden Feb. 26, 1935 2,124,234 McCormack July 19, 1938 2,135,515 Hull et a1. Nov. 8, 1938 2,135,881 Wentworth Nov. 8,1938 2,137,962 Weiher Nov. 22, 1938 2,141,053 Tarleton Dec. 20,1938 2,174,536 Smith Oct. 3, 1939 2,215,512 Kucher Sept. 24, 1940 2,246,275 Davidson June 17, 1941 2,395,065 Rataiczak Feb. 19, 1946 FOREIGN PATENTS Number Country Date 348,521 Great Britain May 5, 1931