US3799707A

US3799707A - Rotary compressor

Info

Publication number: US3799707A
Application number: US00261830A
Authority: US
Inventors: A Newton
Original assignee: Borg Warner Corp
Current assignee: Borg Warner Corp
Priority date: 1972-06-12
Filing date: 1972-06-12
Publication date: 1974-03-26
Anticipated expiration: 1991-03-26

Abstract

A capacity control system for a rotary gas compressor of the sliding vane type having a rotor placed eccentrically within a working chamber provided by the cylinder of a stator housing, the rotor carrying blades or vanes freely slidable in slots in the rotor to engage the cylinder. A control plate is positioned between the rotor and one of the housing cover plates and has an arcuate aperture providing a flow path for refrigerant gas. The control plate is rotatably adjustable to locate the aperture in relation to slots in the rotor periphery, between the blades, to vary the effective size of the compression chamber.

Description

United States Patent [1 1 Newton Mar. 26, 1974 ROTARY COMPRESSOR Primary ExaminerC. J. Husar Assistant Examiner-Leonard Smith [75] Inventor AIM. B. Newton York 133' Attorney, Agent, or Firm-Donald W. Banner [73] Assignee: Borg-Warner Corporation, Chicago,

57 ABSTRACT [22] Filed: June 12, 1972 1 A capacity control system for a rotary gas compressor pp No: 261,830 of the sliding vane type having a rotor placed eccentrically within a working chamber provided by the cylin- 52 us. (:1 418/77, 418/78, 418/79, def Of a Stator using, the rotor carrying blades 0r 418/270 vanes freely slidable in slots in the rotor to engage the 51 Int. Cl. F04c 15/04 cylinden A Control Plate is PSltined between [58 Field of Search 1. 418/16, 30, 183, 77, 78, rotor and one of the housing Plates and has 418/79 270 arcuate aperture providing a flow path for refrigerant gas. The control plate is rotatably adjustable to locate [56] References Cited the aperture in relation to slots in the rotor periphery, UNITED STATES PATENTS between the blades, to vary the effective size of the compression chamber. 3,l20,8l4 2/1964 Mueller 417/310 6 Claims, 2 Drawing Figures 1 ROTARY COMPRESSOR SUMMARY or THE INVENTION This invention relates to gas compressors and more particularly to capacity control systems for rotary gas compressors.

.One type of conventional rotary gas compressor comprises a bladed rotor eccentrically mounted in a cylindrical statorhousing including inlet or suction and outlet or discharge ports communicating with a crescent-shaped working chamber defined between the rotor and housing. In operation, displacement of the rotary compressor is essentially constant per revolution.

The rotary gas compressor of the present invention is characterized by the provision of a capacity control system including a compression control member in the form of a plate rotatably positioned between the bladed rotor and its stator housing and carried by the housing, the plate having control passages cooperating with control slots in the rotor periphery between the blades to vent the gas compression chamber to the suction side of the compressor in response to rotation of the plate to thereby control the effective size of the compression chamber and the amount of capacity of the compressor so as to establish a desired setting conducive to its most efficient operation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view-of a rotary gas compressor having an improved capacity control system; and

FIG. 2 is a cross-sectional view taken along the plane of line 2-2 of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS. 1 and 2, the gas compressor embodies the improved control system of the present invention and comprises a rotor assembly 11 rotatable within a stator assembly 12 and which serves as a housing for the rotor assembly. More particularly, the stator assembly 12 comprises a housing including an annular member 13 and cover plates 14 and 15 providing end walls closing the open ends of the annular member 13 and held in engagement with the same by a plurality of bolts 16. The plates 14 and 15 are bored as at 17 and 18 to provide bearings for rotatably mounting the rotor assembly 11.

The rotor assembly 11 comprises a cylindrical rotor 19 having a plurality of equidistantly-spaced slots 20 adapted to receive vanes or blades 21 slidable reciprocally therein. Rotor 19 is keyed at 22 to a drive shaft 23 journalled in the bearings 17 and 18 in plates 14 and 15 of the stator assembly and rotated by a pulley 24 driven by a motor (not shown) or other suitable drive means. In the case of an automotive application, the compressor is usually driven from the engine through an accessory drive system.

As shown in FIG. 2, the hollow substantially cylindrical inner surface 25 of the stator housing is provided with contact area 26. Since the rotor is rotatably mounted on an axis 27 offset from the center-line of the cylinder 25, the rotor is substantially in sliding contact with the cylinder at 26, leaving a generally crescentshaped working chamber 28 extending over a substantial portion of the inner periphery of the stator housing 13. The direction of rotation of the rotor is indicated by the arrow in FIG. 2.v

As shown in FIG. 2, the annularmember 13 of the stator housing is provided with a suction or inlet port 29 connected to the chamber 28. Also, a discharge or outlet port 30 is provided in the annular member 13, the port 30 communicating with the working chamber 28.

The improved control system comprises the slots 32, which are formed in the periphery of the rotor and are of small volume and disposed near theleading edge of each vane. If desired, the slots may be located elsewhere, even adjacent the trailing edges of the vanes. The system includes an annular member or plate 33 positioned within a cylindrical recess or cavity 34 in the housing end plate 15 and between the rotor 19 and plate 15, the drive shaft 23 extending through the central opening in the plate 33. The cylindrical cavity 34.

in the housing has its center located eccentrically to the center of the housing surface 25 and concentric with the axis of the rotor so that it completely covers the contiguous side of the rotor. The control plate 33 is rotatable in the housing recess 34 by a pinion or gear 35 having its teeth meshedwith the ring gear teeth 36 on the side of the plate 33. The pinion 35 is formed or fitted on the inner end of an operating shaft 37 mounted in a suitable sleeve bearing 38 in the end plate 15 and extending upwardly and exteriorly of the plate 15 so as to be manually rotatable by the knurled knob 39 fixed to the shaft 37 to rotate the control plate 33.

As shown in FIG. 2, the annular control plate 33 is provided with an arcuately-shaped aperture 40. The slots 32 in the rotor periphery communicate with the working chamber 28 and are located to intercept the arcuate aperture 40 in the plate 33 upon rotation of the a rotor. The aperture is of such length as to span the distance between any two adjacent slots.

In the operation of the control system, the control plate 33 is operative to vary the effective length of the suction portion of the working chamber 28 and its corresponding volume. More particularly, when the plate is moved to the position shown in FIG. 2, the aperture 40 is located in its extreme clockwise position so that the suction is not closed until a point close to the discharge port 30. When the plate 33 is moved to its extreme couner-clockwise position, the suction closes at a point much closer to the inlet port 29 and the volume of gas admitted is correspondingly larger and the compressor capacity is increased.

It will be apparent that there is provided an improved and satisfactory system for controlling the existence and the amount of capacity reduction of rotary compressors with a minimum of loss in efficiency.

What is claimed is:

1. A rotary compressor comprising a housing having a closed working chamber provided with a substantially cylindrical surface, said housing having an inlet port and an outlet port communicating with said chamber; a rotor mounted in said chamber and rotatable about an axis eccentric to the axis of said cylindrical surface, said rotor having contact with said cylindrical surface at one point on its periphery, and a plurality of vanes slidably supported in said rotor and engaging said cylindrical surface, said rotor having slots in the periphery thereof between said vanes and each slot communicating with said chamber; and a control member mounted in said housing and provided with an aperture capable of spanning two adjacent rotor slots and operative to connect slots consecutively positioned in communication therewith by rotation of said rotor, said control member being positioned in said housing to vent the compression side of the chamber, through said aperture and the slots connectible thereto, to the suction side of the chamber to control the capacity of the compressor.

2. A rotary compressor as defined in claim 1 in which said control member is rotatable relative to said housing for adjustment to different positions effective to vary the capacity of the compressor.

3. A rotary compressor as defined in claim 1 in which said control member comprises an annular plate engaging one side of said rotor and which side is provided with said slots connectible to said aperture of said plate.

4. A rotary compressor as defined in claim 4 in which said plate is rotatable about the axis of rotation of said rotor for adjustment to different positions effective to vary the capacity of the compressor.

5. A rotary compressor as defined in claim 1 in which said housing comprises an annular member having said inlet port and cylindrical surface, and spaced walls closing the open ends of said annular member to provide said chamber with one of said walls having a recess, and said control member comprising an annular plate concentric to the axis of said rotor and mounted in said recess to engage the side of said rotor.

6. A rotary compressor as defined in claim 5 in which said control plate is rotatable relative to said rotor and said housing for adjustment to different positions effective to vary the capacity of the compressor.