US2739539A

US2739539A - Power transmission

Info

Publication number: US2739539A
Application number: US314650A
Authority: US
Inventors: Duncan B Gardiner
Original assignee: Vickers Inc
Current assignee: Vickers Inc
Priority date: 1952-10-14
Filing date: 1952-10-14
Publication date: 1956-03-27
Anticipated expiration: 1973-03-27

Description

March 27, 1956 D. B- GARDINER POWER TRANSMISSION Filed Oct. 14, 1952 FIG.|

FIG. 2

INVENTOR. DUNCAN B. GARD'NER ATTORNEY PGWER TRANSMHSSION Duncan B. Gardiner, Detroit, Mich, assignor to Viclrers incorporated, Detroit, Mich a corporation of Michigan Application October 14, 1952, Serial No. 314,650

Claims. ((11. 103-136) This invention relates to power transmissions, and is particularly applicable to those of the type comprising two or more fluid pressure energy translating devices, one of which may function as a pump and another as a fluid motor.

More particularly, the invention relates to fluid pumps or motors of the type having telescopically disposed rotor and stator elements of substantially the same axial thickness. Exemplary of such units are those utilizing intermeshing impellers of the gear type and those having a rotor provided with vanes radially slidable into contact with an encircling cam ring.

One of the major problems of designing such pumps and motors is to provide proper end clearance between relatively rotatable parts so as to have a free running unit and yet maintain high volumetric eificiency. Unavoidable deflection of those components under pressure further complicates the issue. A pump design which has been highly successful in meeting this problem is illustrated in the patent to Duncan B. Gardiner et al., 2,544,988.

The Gardiner patent utilizes a pressure plate having a shoulder which abuts the stator element and a central portion which overlies the rotor to provide end clearance. The unsupported central portion of the plate is deflectable toward the rotor in response to increasing operating pressure to decrease that end clearance. Thus reducing the end clearance at higher pressures permits high volumetric efl'ieiency and a free running pump over a wide range of pressures. The continuing trend toward higher operating pressures of the order of 3000 p. s. i. has, however, necessitated an undesirable increase in the pressure plate thickness and provision of end clearances which are excessive during low pressure operation.

It is an object of the present invention to provide an improved low cost rotary fluid pump or motor.

A further object is to provide such a unit which is capable of eflicient operation over a wider range of pressures than prior devices.

Another object is to provide such a unit having automatically adjustable end clearance to compensate for wear.

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

In the drawing:

Figure l is a longitudinal section of a vane pump embodying a preferred form of the present invention.

Figure 2 is a transverse section taken on line 22 of Figure 1.

Figure 3 is a transverse section taken on line 3-3 of Figure 1.

Referring now to Figure 1 the pump comprises a body 10, ring 12, and a head 14 arranged in a sandwich relation and secured together by a plurality of bolts 16 extending through head 14 and ring 12 into threaded holes in body rates Patent be 10. O ring seals 18 and 20 insure a fluid tight juncture of head 14 and body 10 with ring 12.

The ring 12 provides a stator element having a generally elliptically contoured bore 22 therein. A rotor 24, carrying a plurality of vanes 26 slidable in substantially radial slots 23, is positioned in bore 22 in a telescopic relation with ring 12. During operation of the pump the ends of vanes 26 are maintained radially outward against bore 22 by centrifugal force aided by pressure conducted to the inner ends of the vanes by a pair of similarly proportioned

annular channels

30 and 32 in rotor 24 which intersect the enlarged inner ends of slots 28.

The spaces between adjacent vanes may be termed working chambers and it should be noted that each has a complementary working chamber diametrically opposed thereto. For example, chambers 34 and 36 are a complementary pair as are 38 and 40. Assuming a counterclockwise rotation of rotor 24, as viewed in Figure 3, it can be seen that chambers 34 and 3 6 are at the moment increasing in volume while chambers and 40 are decreasing. A hydraulically balanced pumping action is thus provided. Such pumping mechanism is described in more detail in the patent to Harry F. Vickers, 1,989,900.

Body 10 includes a plane face 42 which axially abuts ring 12 and against which rotor 24 and vanes 26 are axially slidable. A pair of kidney-

shaped inlet ports

44 and 46 in the face 42 are so positioned as to overlie the expanding working chambers, and they communicate through a branched passage 4a with a threaded external connection port 50 in the flange 52. A drive shaft 54, splined at 55, extends through passage 48 and a clearance hole 57, in face 42, to engage rotor 24. Shaft 54 is supported by a pair of spaced bearings 56 and 5'3. A conventional shaft seal 61 is provided in body 10 to prevent leakage therefrom.

The head 14 has a recess therein which has its open end adjacent ring 12 and rotor 24. Pressure plate 62 is axially slidable in recess 60 and is biased into engagement with ring 12 by a spring 64. Plate 62 is in peripheral fluid sealing engagement with bore 60 and presents an annular plane face 66 to ring 12 and the adjacent ends of rotor 24 and vanes 26. Pressure plate 62 cooperates with bore 60 to form a pressure chamber 68 from which a delivery passage 70 extends to a threaded external connection port 72 in a flange 74. A pair of kidney-

shaped outlet ports

76 and 78 extend from face 66 completely through pressure plate 62 into communication with pressure chamber 68. Proper angular alignment.

between body 10, ring 12, and pressure plate 62 is maintained by a pair of dowel pins 79 extending from the body through the ring and into the plate. Operating pressure of the pump thus exists in chamber 68 and is conducted through a plurality of drilled passages to

channels

30 and 32 for a purpose heretofore discussed. it is pointed out that the dotted outlines of ports 76 and 13, as well as that of bore 66, in Figure 2 are merely to illustrate positional relations and are not hidden object lines.

Face 66 of plate 62 is in fluid sealing proximity with those areas of the ring 12, rotor 24, and vanes 26 which are speckled in Figure 3. Rotor 24 and vanes 26 are made slightly thinner than ring 12 to provide running clearance between face 66 and their adjacent ends. Pressure in chamber 68 will aid spring 64 in biasing plate 62 against ring 12 and further, will induce deflection of the plate 62 into bore 22 toward rotor 24 and vanes 26 much in the manner of the cheek plate in the Gardiner patent heretofore mentioned.

Pressure plate 62 has a stepped bore 80 therein having its larger and adjacent rotor 26. A large piston 82 provided with an 8 ring seal 84 and a smaller piston 86 provided with an O ring seal 88 are axially slidable in bore 80. Spring 90, acting through piston 86, resiliently biases piston 82 toward rotor 24. A drilled passage 92 in piston 82 extends from the area intermediate the two pistons to a circular central recess 94 in rotor 24. The recess 94 drains to the return passage 48 through the clearance around spline 55. Operating pressure .in chamber 68 thus acts on the area of piston 86 to bias piston 32 toward rotor 24. The inner edge of channel 30 and the outer edge of recess 94 form, respectively, the outside and the inside diameters of an annular surface 96 on rotor 24 toward which piston 82 is biased. Piston 82 is selected to have its outside diameter identical to the outside diameter of annulus 96. As heretofore noted, operating pressure exists in channel 30 and tank pressure exists in recess 94. In accordance with well known hydraulic principles, 2. thin film of oil will extend over the annulus 96 between rotor 24 and piston 82 during operation of the pump. Pressure in this film will be in a uniform gradient from operating pressure at the outside diameter to tank pressure at the inside diameter, and will tend to separate the rotor 24 and piston 82. The mean effective unit pressure in the annular film will be approximately one-half the operating pressure. Thus, to counteract separating force in the annular film tending to move piston 82 away from rotor 24, the small piston 86 provided with an effective area exposed to operating pressure in chamber 68 which is approximately one-half that of annulus 96. Actually, the area of piston 86 is made slightly more than one-half than that of annulus 96, thus insuring against separation of piston 82 and rotor 24 due to pressure in the film.

As heretofore noted,

channels

30 and 32 are similarly proportioned and each has operating pressure of the unit therein. For the purpose of hydraulically balancing rotor 24 in the axial direction, shaft clearance hole 57 preferably has the same diameter as recess 94, thereby providing an annular area 98, equal in area and opposed to area 96, having similar pressure conditions thereacross.

It should be noted here that

pistons

82 and 86 in effect comprise a differential piston and could be made in one piece. More liberal eccentricity and squareness tolerances are possible with the construction shown, however.

It can be seen that the area of piston 86 can be reduced if accompanied by a corresponding reduction in the area of annulus 96. The relation between

pistons

86 and 82 should be such that during operation of the pump the product of the operating pressure and the eflfective area of piston 86 slightly exceeds the product of the opposing effective area of piston 82 and the mean effective unit pressure thereon.

The axial sealing function has thus been broken down into two distinct phases. Pressure plate 62 is urged by spring 64 and pressure in chamber 68 into fluid sealing proximity with the speckled areas in Figure 3 while spring 90 and pressure in chamber 68 urge piston 82 into fluid sealing proximity with the annular area 96 on rotor 24.

The invention has provided axial scaling for a rotary pump or motor which has the advantages of deflection sealing as described in the heretofore mentioned Gardiner patent but which avoids excessive central deflection under high operating pressures. These ends have been achieved in an improved, low cost unit capable of eflicient operation over a wide range of pressures.

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

What is claimed is as follows:

1. In a fluid pressure energy translating device of the type having telescopically disposed rotor and stator elements of substantially the same axial thickness: an'abutment member presenting a common plane face to one end of both the rotor and stator; a second abutment member having a common plane face overlapping, in a fluid sealing relation, adjoining surfaces at those other ends of both the stator and rotor which are axially opposed to said one end, said second abutment member being axially shiftable toward said elements; a thirdabutment member slidably positioned in the second of the aforementioned abutment members and axially slidable into fluid sealing proximity with the adjacent end of only one of said elements; and means for resiliently biasing said second and third abutment members toward said elements.

2. In a fluid pressure energy translating device of the type having telescopically disposed rotor and stator elements of substantially the same axial thickness: an abutment member presenting a common plane face to one end of both the rotor and stator; a second abutment member having a common plane face overlapping, in a fluid sealing relation, adjoining surfaces at those other ends of both the stator and rotor which are axially opposed to said one end; a third abutment member slidably positioned in the second of the aforementioned abutment members and axially slidable into fluid sealing proximity with the adjacent end of only one of said elements; and means for resiliently biasing said third abutment member axially toward said one element, said means including an area on said third member exposed to operating pressure of the device.

3. In a fluid pressure energy translating device of the type having telescopically disposed rotor and stator elements of substantially the same axial thickness: an abutment member presenting a common plane face to one end of both the rotor and stator; a second abutment member having a common'plane face overlapping, in a fluid sealing relation, adjoining surfaces at those other ends of both the stator and rotor which are axially opposed to said one end, said second abutment member being axially shiftable toward said elements; a third abutment member slidably positioned in the second of the aforementioned abutment members and axially slidable into fluid sealing proximity with the adjacent end of only one of said elements; and means for resiliently biasing said second and third abutment members toward said elements, said means including an area on each of said second and third abutment members exposed to operating pressure of the device.

4. In a fluid pressure energy translating device of the type having telescopically disposed rotor and stator elements of slightly differing axial thickness: an abutment member presenting a common plane face to one end of both the rotor and stator; a second abutment member having a common plane face overlapping, in a fluid sealing relation, adjoining surfaces at those other ends of both the stator and rotor which are axially opposed to said one end, said second member having an area exposed to operating pressure of the device and being .in abutment with the thicker of said elements and deflectable toward the thinner in response to pressure on said area; a third abutment member slidably positioned in the second of said abutment members and axially slidable into'fiuid sealing proximity with the adjacent end of only one of said elements; and means for resiliently biasing said third abutment member axially toward said one element.

5. In a fluid pressure energy translating device of the type having telescopically disposed rotor and stator elements of substantially the same axial thickness: an'abub ment member presenting a common plane face to 'one end of both the rotor and stator; a second abutment member having a common plane face overlapping, in a fluid sealing relation, adjoining surfaces at those other ends of both the stator and rotor which are axially opposed to said one end; a third abutment member slidably positioned in the second of the aforementioned abutment members and axially slidable into fluid sealing proximity with the adjacent end of only one of said elements; and means for resiliently biasing said third abutment member axially toward said one element, said means including an effective area on said third member exposed to operating pressure of the device, so proportioned as to counterbalance the pressure forces tending to separate said third member and said one element. v Y

.6. In a fluid pressure energy translating device of the type having telescopically disposed rotor and stator elements of substantially the same axial thickness: an abutment member presenting a common plane face to one end of both the rotor and stator; a second abutment member having a common plane face overlapping, in a fluid sealing relation, adjoining surfaces at those other ends of both the stator and rotor which are axially opposed to said one end; a third abutment member slidably positioned in the second of the aforementioned abutment members and axially slidable into fluid sealing proximity with an annular area on the adjacent end of only one of said elements; and means for resiliently biasing said third abutment member axially toward said one element, said means including an effective area on said third member exposed to operating pressure of the device so proportioned as to counterbalance the pressure forces across said annular area tending to separate said third member and said one element.

7. In a fluid pressure energy translating device of the type having telescopically disposed rotor and stator elements of substantially the same axial thickness: an abutment member presenting a common plane face to one end of both the rotor and stator; a second abutment memher having a common plane face overlapping, in a fluid sealing relation, adjoining surfaces at those other ends of both the stator and rotor which are axially opposed to said one end; a third abutment member slidably positioned in the second of the aforementioned abutment members and axially slidable into fluid sealing proximity with the adjacent end of only one of said elements; and means for resiliently biasing said third abutment member axially toward said one element, said means including an eflective area on said third member exposed to operating pressure of the device so proportioned that the prodnet of that area and the operating pressure always slightly exceeds the product of the effective area of said third member adjacent said one element and the mean effective unit pressure thereon.

8. In a fluid pressure energy translating device of the type having telescopically disposed rotor and stator elements of substantially the same axial thickness: a body member having fluid passage means therein and presenting a common plane face to one end of both the rotor and stator; port means in said face connected to said fluid passage means; a head member having a recessed end adjacent the rotor and stator elements and having fluid passage means therein connected to the recess; an abutment member in the recess forming a pressure chamber therewith and presenting a common plane face to that other end of both the stator and rotor which is axially opposed to said one end; port means in the plane face of said abutment member; fluid passage means connected to the last mentioned port means and extending through the abutment member to said pressure chamber; a stepped bore extending through said abutment member, having its large end adjacent said rotor and its small end open to said pressure chamber; differential piston means axially slidable in said bore, having a small area exposed to pressure in the pressure chamber and a relatively large area adjacent the rotor.

9. In a fluid pressure energy translating device of the type having telescopically disposed rotor and stator ele ments of slightly difiering axial thickness: a body member having fluid passage means therein and presenting a common plane face to one end of both the rotor and stator; port means in said face connected to said fluid passage means; a head member having a recessed end adjacent the rotor and stator elements and having fluid passage means therein connected to the recess; an abutment member axially slidable in the recess forming a pressure chamber therewith and presenting a common plane face to that other end of both the stator and rotor which is axially opposed to said one end, said face abutting the thicker of said elements and deflectable toward the thinner in response to pressure in said chamber; port means in the plane face of said abutment member; fluid passage means connected to the last mentioned port means and extending through the abutment member to said pressure chamber; a stepped bore extending through said abutment member, having its large end adjacent said rotor and its small end open to said pressure chamber; and differential piston means axially slidable in said bore, having a small area exposed to pressure in the pressure chamber and a relatively large area adjacent the rotor.

10. In a fluid pressure energy translating device of the type having telescopically disposed rotor and stator elements of substantially the same axial thickness: a body member having fluid passage means therein and presenting a common plane face to one end of both the rotor and stator; port means in said face connected to said fluid passage means; a head member having a recessed end adjacent the rotor and stator elements and having fluid passage means therein connected to the recess; an abutment member in the recess forming a pressure chamber therewith and presenting a common plane face to that other end of both the stator and rotor which is axially opposed to said one end; port means in the plane face of said abutment member; fluid passage means connected to the last mentioned port means and extending through the abutment member to said pressure chamber; a stepped bore extending through said abutment member, having its large end adjacent said rotor and its small end open to said pressure chamber; and differential piston means axially slidable in said bore, having a small area exposed to pressure in the pressure chamber and a relatively large area adjacent the rotor, said small and large areas being so proportioned that the product of the area of said small piston and the pressure in the pressure chamber will slightly exceed the product of the large area and the mean effective unit pressure thereon.

References Cited in the file of this patent UNITED STATES PATENTS 465,907 Whipple Dec. 29, 1891 2,044,873 Beust June 23, 1936 2,544,988 Gardiner et al Mar. 13, 1951 2,627,232 Lauck Feb. 3, 1953 2,642,001 Dale et al June 16, 1953 FOREIGN PATENTS 463,304 Italy Apr. 26, 1951