Rotor Supporting Arrangement For A Compressor

Abstract

A stationary pintle projects from one side of a housing into a housing cavity, and has two axially spaced bearing supporting a rotor which has a pot-shaped portion including an endless wall surrounding the pintle and closed by a bottom part to which a drive shaft portion of the rotor is secured. The bearings are either provided between the endless wall and the outer surface of the pintle, or between the drive shaft portion and the inner surface of a tubular pintle. Preferably, the center of gravity of the rotor is located between the bearings.

Description

BACKGROUND OF THE INVENTION

The present invention relates to an improvement in compressors, particularly a compressor of the type in which vanes are slidable in substantial radial slots of a rotor and have outer ends engaging an endless cam surface so that expanding and contracting intervane soaces are formed.

The U.S. Pat. No. 2,046,873 discloses a machine of this type in which the rotor is supported on a pintle on one side of its housing so that a comparatively long bearing is required for the rotor, causing large size of the machine. The machine of the prior art, which operates satisfactorily as a pump when low sealing requirements are made, but cannot be used as a compressor without great disadvantages. In a vane compressor, the tolerances between the rotor and the inner surface of the housing must be exactly observed, and during operation of the compressor, the adjusted play must not change, since otherwise the efficiency of the compressor is unduly reduced. The machine of the prior art is of the one flow type which causes a one-sided load on the bearings. On the other end, great inertia forces of the heavy rotor cannot be prevented at very high rotary speed. This is particularly important if the compressor is to be used in an automobile, and as has been shown by tests, the one sided support of the rotor is hardly capable of resisting the forces produced by the moving masses when oscillation accelerations up to 40g occur during the operation of a motor car provided with the compressor.

SUMMARY OF THE INVENTION

It is the object of the invention to provide a compressor which can be economically manufactured, but has great resistance to wear and a long span of life, even if subjected to high acceleration.

Another object of the invention is to support the rotor of a compressor on two axially spaced bearings on a supporting pintle or trunnion which is located only on one side of the rotor and housing.

In accordance with the invention, the rotor of the compressor is mounted on two bearings on a pintle which at least partly projects into an inner housing cavity, and which supports by the two bearings, a pot-shaped rotor portion whose endless wall surrounds the pintle, and whose bottom part is secured to, or integral with, a drive shaft portion of the rotor which projects on one side of the rotor out of the housing.

The arrangement of the invention has the advantage that the rotor is mounted on a pintle on one side of the housing, but is supported on two axially spaced bearings. Due to the one-sided support, easy adjustability of the gap between the rotor and the inner endless housing surface is obtained, and on the other hand, the bearing support is capable of withstanding even very high loads.

It is particularly advantageous to support the pintle on one side wall of the housing which closes the cavity of the housing at one axial end, and to mount the side wall on a pivot supported in the housing and permitting angular adjustment of the side wall with the pintle and the rotor relative to the inner endless cam face of the housing.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an axial sectional view illustrating a first embodiment of the invention;

FIG. 2 is a cross sectional view of the embodiment of FIG. 1; and

FIG. 3 is an axial sectional view of a second embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to FIGS. 1 and 2, a vane compressor has a housing with five parts. An annular central housing part 1 forms together with two side walls 2 and 4 an inner cavity. The side walls 2 and 4 are covered by outer covers 3 and 5 which are held together by threaded bolts 28 and nuts 30. The annular central housing wall 1 is double-walled and includes an outer wall 6a and an inner wall 6 connected by ribs 6b in such a manner that chambers are formed between the inner wall 6 and the outer wall 6a.

The inner endless wall 6 has an inner endless camming surface 6c of elipsoid shape which is the outer boundary of the housing cavity 7. A rotor 8 is arranged in cavity 7, and has a diameter which, with small play, has a length corresponding to the length of the small axis of the elipsoid inner camming surface 6c. Between the outer surface of rotor 8, and the inner elipsoid surface 6c of the endless inner wall 6, two crescent working spaces are formed which are divided into suction chambers 7a and pressure chambers 7b by radial vanes 11 mounted in radial slots formed by inner ribs 10 of the rotor 8. As best seen in FIG. 1, rotor 8 has a pot-shaped portion including an endless wall 8a and a bottom 12. The rotor has a drive shaft portion 13 which is secured to the bottom part 12 of the pot-shaped portion 8. The endless wall 8a surrounds a tubular pintle 14 mounted on side wall 2 and having a portion projecting into the cavity 7, and an axially outer portion projecting into the space between the cover 3 and side wall 2.

The drive shaft portion 13 of the rotor passes through the inner bore of tubular pintle 14, and is supported in two axially spaced bearings 15 and 16 mounted in the inner bore of pintle 14 at the ends of the pintle.

The radial outer ends of the vanes 11 slidingly engage the inner elipsoid camming surface 6c and divide the crescent-shaped spaces between the rotor and the camming surface 6c, into expanding suction chambers 7a and pressure chambers 7b. The region of the suction chambers is connected by openings 17 in the inner wall 6 with suction chambers 18 formed between the inner wall 6 and the outer wall 6a of the central housing portion 1. The pressure chambers 7b communicate with pressure chambers 21 between housing walls 1 and 6 through outlets 19. Check valve means 20 including springs 32 and abutment members 33 close the outlet 19, but are opened by pressure fluid entering the chamber 21 through outlets 19. Part-cylindrical springs 34 urge a base plate 35 of the check valve means 31 against the outside of the inner wall 6. The check valve arrangement is not an object of the present invention.

On the right side of FIG. 1, the side wall 4 and the cover wall 5 close the inner cavity within the endless wall 6. The cover 5 forms an annular channel 22 which interconnects the pressure chambers 21 in the central housing part 1 with the outlet 23. An annular channel 25 between the cover 3 and the side wall 2 connects the suction chambers 18 with the inlet 26. A bore in cover 3 through which the drive shaft portion 13 of rotor 8 passes, is sealed by an axial sealing means 27.

When the rotor 8 is rotated by operation of the drive shaft portion 13, the vanes 11 move along the endless inner camming surface 6c of the inner endless wall 6 which bounds the housing cavity 7. The intervane spaces 7a expand, and draw the fluid through the opening 17. During further rotation, the intervane spaces 7b contract, so that the compressed medium is discharged through the opening 19 and the check valve means 20 out of outlet 23.

Due to the construction of the compressor permitting two flows of the fluid, the rotor 8 is completely relieved of fluid pressure, so that the rotor can be mounted on the one-sided pintle 14. The one-sided support of the rotor permits easy adjustment of the play between the outer surface of the rotor and the inner surface 6c of planar wall 6. The pivot pin 24, secured to the central housing portion 1, supports the pintle 14 for angular adjusting movement with rotor 8 relative to the inner surface 6c. It is particularly advantageous for the load on bearings 15 and 16 if the center of gravity of the rotor is located between the bearings 15 and 16 and preferably if a vertical line from the center of gravity passes through the axis of the rotor shaft 13 and of the bearings 15 and 16.

The arrangement of the invention shown in FIG. 1 permits the mounting of the rotor 8, and more particularly of its drive shaft portion 13, on two axially spaced bearings 15 and 16 supported on the side wall 2 by pintle 16, without requiring one of the bearings to be located outside of the other side wall 4.

FIG. 3 shows another embodiment of the invention whose general construction is similar to the construction of the embodiment of FIGS. 1 and 2, but the rotor is differently constructed. The housing consists of five parts, a central housing portion 41, two side walls 42 and 44, and two covers 43 and 45. A pintle 54 is supported on the side wall 42 projecting into the cavity 7 formed by the inner endless camming surface 47. As in the embodiment of FIG. 1, the free end of the pintle 54 is spaced from the side wall 42, and the rotor 48 has a pot-shaped portion with an endless wall 48 surrounding pintle 54 and the bottom part 48b located adjacent side wall 42. The bottom part 48b is integral with the drive shaft portion 53 which is mounted in the cover wall 43, sealed by sealing means 67. The endless wall of the pot-shaped rotor portion 48 surrounds the pintle 54, and between the inner cylindrical surface of the endless wall 48a and the outer surface of the pintle 54, axially spaced bearings 55, 56 are provided so that the rotor is supported for rotation on the pintle 54. A bore 54a in pintle 54 reduces the weight of pintle 54. Bearings 55 and 56 are preferably roller bearings. A pivot pin 64 is secured to the central housing part 41 and projects into a bore of side wall 44 permitting angular adjustment of side wall 44 with pintle 54 and rotor 48 relative to the inner endless camming surface 47 on which the outer ends of the vanes slide.

The embodiment of FIG. 3 has the advantage that the drive shaft portion 53 is short. In the embodiment of FIGS. 1 and 2, the drive shaft portion 13, which passes through the interior of the pot-shaped rotor portion, is much longer so that resonance oscillations are possible which are avoided by the embodiment of FIG. 3.

In both embodiments, the bottom part 12 or 48b of the pot-shaped rotor portion, is located between the free end of pintle 14 or 54 and the respective side wall 4 or 44.

Generally speaking, the arrangement of the present invention comprises housing means including first and second side wall means 2, 3, 4, 5 or 42, 43, 44, 45 and forming a cavity 7; a stationary supporting pintle 14 or 54 secured at one end to one of said side wall means and projecting therefrom into said cavity, the other end of said pintle being spaced from the respective other side wall means; rotor means 8 or 48 having an axis and located in said cavity 7, said rotor means including a pot-shaped portion having an endless wall 8a or 48c surrounding said pintle 14 or 54, and a bottom part 12 or 48a located between said other end of said pintle and said other side wall means, said rotor means 8 or 48 further including a drive shaft portion 13 or 53 projecting from said bottom part 12 or 48a through said first side wall means 2, 3 or 42, 43 out of said cavity; and two bearings 15, 16 or 55, 56 located spaced along the length of said pintle 14 or 54 and supporting said rotor means on said pintle for rotation about said axis.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of rotor supporting arrangements for compressors differing from the type described above.

While the invention has been illustrated and described as embodied in a compressor in which the rotor is supported on two bearings axially spaced along a pintle, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

Claims

We claim:

1. Rotor supporting arrangement for a compressor, comprising housing means including first and second side wall means, and forming a cavity; a stationary supporting pintle projecting from one of said side wall means into said cavity and having a free end spaced from the respective other side wall means; rotor means having an axis, and located in said cavity, said rotor means including a pot-shaped portion having an endless wall surrounding said pintle, and a bottom part located between said free end of said pintle and said other side wall means, said rotor means further including a drive shaft portion projecting from said bottom part through said first side wall means out of said cavity; and two bearings mounted on said pintle spaced from each other and supporting said drive shaft on said pintle for rotation about said axis.

2. Arrangement as claimed in claim 1, wherein said axis of said rotor means and of said bearings is horizontal; and wherein a vertical line through the center of gravity of said rotor means passes between said bearings.

3. Arrangement as claimed in claim 2, wherein said vertical line and said horizontal axis intersect in a common plane.

4. Arrangement as claimed in claim 1, wherein said one side wall means include an outer cover, and a planar end wall bounding one axial end of said cavity and supporting said pintle.

5. Arrangement as claimed in claim 4, wherein said housing means includes a central annular housing part on which said first and second side wall means abut, and a pivot pin secured to said annular central housing part and mounting said end wall for angular adjustment with said pintle.

6. Arrangement as claimed in claim 1, wherein said one side wall means is said first side wall means and said other side wall means is said second side wall means; wherein said pintle is tubular and has an inner cylindrical bore; wherein said bearings are mounted in said cylindrical bore; and wherein said drive shaft portion is located in said cylindrical bore supported on said bearings and passes through said endless wall of said pot-shaped part, said drive shaft portion being secured to said bottom part so that said pot-shaped portion of said rotor means is supported by said drive shaft portion on said tubular pintle.

7. Arrangement as claimed in claim 6, wherein said tubular pintle includes a tubular portion projecting axially outward from said first side wall means; and wherein one of said bearing is located in said tubular portion.

8. Arrangement as claimed in claim 1, wherein said one side wall means is said second side wall means; wherein said bottom part is located adjacent said first side wall means; wherein said drive shaft portion is secured to the outside of said bottom part and projects out of said cavity through said first side wall means; and wherein said bearings are located between the outer surface of said pintle and the inner surface of said endless wall of said pot-shaped portion of said rotor means.

9. Arrangement as claimed in claim 8, wherein said bottom part is integral with said drive shaft portion.

10. Arrangement as claimed in claim 1, wherein said bottom part has a slide face slidingly engaging said free end of said pintle.