US3011452A - Hydraulic apparatus - Google Patents

Description

Dec. 5, 1961 T. BUDZICH 3, 5

HYDRAULIC APPARATUS Filed Jan. 4, 1960 2 Sheets-Sheet l IN VEN TOR. TA DE USZ BUDZ 6 H A TTOR/VE Y Dec. 5, 1961 T. BUDZICH 3,011,452

HYDRAULIC APPARATUS} Filed Jan. 4, 1960 2 Sheets-Sheet 2 IN VENTOR. TADEUSZ BUDZ/CH w myu cw United States Patent 3,011,452 HYDRAULIC APPARATUS Tadeusz Budzich, 3344 Colwyn Road, Cleveland, Ohio Filed Jan. 4, 1960, Ser. No. 127

13 Claims. (Cl. 103173) The present invention relates generally tohydraulic apparatus and more. particularly to fluid pressure energy I translating pumps and motors of the axial piston type in which a stationary but free floating cylinder barrel carpump housing. Since the axial forces in high pressure pumps are large, the anti-friction bearings usually are expensive, bulky and a limiting factor as far as the life of the unit is concerned. Another disadvantage of this type of unit lies in the fact that the cylinder barrel is usually rigidly located with respect to the pump or motor housing and this makes the selection of pump valving difficult. But despite these disadvantages, this type of construction carries one basic advantage over the type of pump employing a rotating cylinder barrel. This advantage lies in the absence of centrifugal forces to which piston assemblies are subjected in rotating cylinder barrel pumps. Due to the absence of such centrifugal forces the stationary cylinder barrel type pump can operate at much higher r.p.rn. I

- An object of the present invention is to provide an improved pump or motor retaining all the advantages of apparatus employing a stationary cylinder barrel while at the same time eliminating all major disadvantages usually associated with this type of design.

Another object of the invention is toprovide a pump with a non-rotating cylinder barrel capable of aligning itself to the flat face of a valve plate.

Another object of the invention is to provide an improved construction by which oil from a rotating valve plate is transferred, as to a pump outlet, With minimum leakage and friction losses.

In accordance with one aspect of the present invention, I meet these and other objects by providing a pump having a free floating non-rotating cylinder barrel in combination with the provision of anti-friction bearings located at opposite ends of a tie shaft connecting a cam plate and valve plate, taking care of all transverse components of the reaction forces while the axial forces induced by the pressure loads acting on the pistons are carried in tension by such a tie member connecting rotatable cam at one end of the cylinder barrel with valve plate at the opposite end thus eliminating the necessity of high-priced, short-lived, and bulky anti-friction bearings.

Other objects and advantages will become apparent and the invention may be better understood from consideration of the following description of a preferred embodiment taken in connection with the accompanying drawings in which:

FIG. 1 is a longitudinal section view of a fluid pump or' motor illustrating a tie member shaft connecting rotary cam plate and rotary valve plate;

'FIG. 2 is a longitudinal section showing a portion of the pump as in FIG. 1 but with the valve plate rotated 90;

FIG. 3 shows end face of cylinder barrel (and crosssection of tie rod) as viewed along the line 3-3 of FIG. 2;

we 3,011,452 Patented Dec. 5, 1961 ice The device as shown in FIGS. 1-4 will be described as a motor, although it can work just as well as an arcuate pump. A motor body 10 is closed at one end by an end cover 11 secured by a series of bolts 12. The end cover 11 and body 10 carry two anti-friction bearings 13 and 14 locating a driving shaft 16. The shaft 16 is equipped at one end with a valve plate 17 permanently secured as by welding to a collector sleeve 18, and on the other end the shaft rotatably engages, through a pin 20, sleeve 21 and snap-ring 22, a cam plate 23. A relatively stationary cylinder barrel 25 works in operational engagement at one end with the valve plate 17 and at the other end the barrel 25 is slideably and universally mounted by a surface 26 provided on an annular extension 27 of the cylinder barrel. The surface 26 of the cylinder barrel is radially located e.g., with a clearance, in a sleeve 28 which, in turn, is located in the body 10 and axially constrained by cover 11. The sleeve 28, as can 'be seen in the drawings, has a cylindrical surface 28a (FIG. 5) contacting the arcuate surface 26 of the cylinder barrel to provide the universal mounting. The cylinder barrel 25 is prevented from rotation by a pin 30 working in an oversize hole 31 provided in the surface 26.

Cylinder barrel 25 is equipped with a series of longitudinal bores 33 in which pistons 34 are slideably mounted for reciprocation. The pistons 34 have part-spherical ends 35, and universally mounted piston shoes 36 work in Contact with a fiat face of the cam plate 23 and are axially constrained from leaving this flat surface by a nutating plate 38 engaging a circular flange portion 40 of each piston shoe 36. The piston shoes 36 are hydrostatically balanced in well-known manner as by each having a recess 41 containing high-pressure oil, and balancing lands 42. The high pressure oil is conducted to the recess 41 by a drilling through shoes 36 and by longitudinal drillings (not shown) along the center lines of the pistons 34. The nutating plate 38' is mounted adjacent the outer periphery of cam plate 23 which, in turn, is permanently connected to sleeve 21 which is in rotatable engagement with the shaft through pin 20, the snapring 22 carrying the full axial force of the hydraulic reaction. A compression spring 44 has one end located in a recess pro- Vided in the pump cover 11 and has it other end engaging a flat end surface of the annular extension 27 of the cylinder barrel 25.

At the opposite end of the cylinder barrel 25 a flat surface thereof works in operational contact with the Valve plate 17 and is, as is shown in FIG. 3, equipped with a series of kidney-shaped slots 46. Sequentially brought into register with the individual slots 46 is a valve plate kidney-slot 47 (see FIG. 4) conducting fluid in or out of the cylinder barrel depending on Whether the device is working as a pump or as a motor. Dyna-mic pads 43 stabilize the cylinder barrel 25 on the surface of the valve plate 17. The kidney 47 of the valve plate 17 is connected by series of drilled holes 49 with a central bore 54 housing the collector sleeve 18. A flat end face of the collector sleeve 18 works in sliding operational contact with a balance sleeve 51, mounted in the housing 10 with limited universal freedom and sealed by an 0 ring 52 and prevented from rotation by a pin 53 working in a hole provided in a flange portion 54 of sleeve 51.

action) pressure fluid, and, as most clearly seen in FIG.

. 2, the path of such fluid will then be through the in-.

terior of sleeve 51, then through sleeve 18 to space 50, passages 49, port 47, to associate kidneys 46 of the cylinder barrel, while a low pressure port 57 is used to connect the inside of the housing 10 with a reservoir of low pressure discharge or suction oil depending on whether the unit is working as a motor or as a pump.

Operation of the unit The operation of the unit will be described as that of a high-pressure motor. The housings cylinder barrel mounting sleeve 28 acts as a circular reaction ring per- I manently retained in the pump housing 10 and clamped in position by cover 11. The cylinder barrel 25 with its annular extension 27 equipped with surface 26 is mounted with respect to this reaction ring 28. The cylinder barrel 25 is prevented from rotation (about its own axis) by pin 30 which engages hole 31 which is made substantially oversize so that it doesnt impair the freedom of alignment of the cylinder barrel 25. The fiat face of the cylinder barrel 25 works in operational contact with the flat face of the valve plate 17 which is rotationally connected through the shaft 16 with the cam plate 23. The cylinder barrel 25 retains the slide able pistons 34 which Work in operative association, through piston shoes 36, with the cam plate 23. Oil is supplied through the port 55 eventually reaching some of the ports 46 in the cylinder barrel 25. A line dividing the valve plate into low pressure and high pressure areas is so positioned, in respect to cam plate 23, that with end to end projection it coincides with the principal axis of the cam 23. Such a cam principal axis is a center line passing along the greatest inclination of the cam surface and through the center of rotation. Then, the valve plate kidney-shaped recess 47 will connect high pressure oil to cylinder bores positioned on one side of the principal axis of the cam. The force induced by this high pressure oil acting on the cross-section area of the associate pistons 34 is transmitted through the universal jointspheres 35 and piston shoes 36 to the surface of the cam plate 23. The axial force of the hydraulic piston reaction acting on the inclined plane of the cam plate 23 will transmit to it a rotary moment, as is well known in the art.

Since the cylinder barrel 25 is constrained from rotation by the pin 30, the full torque (proportional to the hydraulic reaction force and the angle of inclination of the cam plate 30) will be transmitted to rotate the cam plate 30 and therefore, through the pin 20, to rotate shaft 16, and valve plate 17, and any connected (driven) load, all of which will revolve under action of the induced torque.- However, the forces of the hydraulic reaction acting through the pistons, and on the inclined face of the cam plate 23, will not only induce torque but, at the same time, will induce a proportional transverse load which must be carried by the bearings 13 and 14. At the same time the transverse component of the piston hydraulic reaction force acting through the center of the spherical piston ends 35 will induce a bending moment in each piston 34 involved and will therefore induce a transverse moment in the cylinder barrel 25. This transverse moment acting on the cylinder barrel 25 and induced by certain ones of the pistons 34 will tend to rotate the cylinder barrel 25 in a certain direction along the point of contact between the surface 26 and reaction ring 28. A transverse moment of the same magnitude will be transmitted to the cylinder barrel 25 from each piston assembly subjected to high pressure oil.

In this way the transverse moments acting on the cylinder barrel cancel each other leaving the cylinder barrel free to align itself to the valve plate.

With the cam plate 23 inducing a rotational movement of shaft 16, the valve plate will rotate, sequentially connecting piston assemblies located on one side of the principal axis of the cam plate 23'. In this way a continuous rotation of the mechanism can be obtained. It is Well known in the art that for most efiicient operation a cylinder barrel (such as 25) should be capable of aligning itself to an associate valve plate. In accordance with the present invention the total sum of piston reaction force is transmitted to cam plate 23, thus to sleeve 21 to which the cam plate is permanently secured, and the axial components are transmitted from sleeve 21 to snap ring 22- which prevents axial movement between cam plate and shaft 16. As shown, the sleeve 21 is provided with a cylindrical extension portion 21e closing over snap-ring 22 to prevent it leaving a corresponding groove in the shaft.

Meanwhile equal and opposite. reaction force acting on cross-section area of the cylinder bore and valve plate is transmitted to the cylinder barrel 25 and to the valve plate 17. In some conventional designs these two forces are carried by separate thrust bearings. But in accordance with the present invention these very large axial reaction forces are carried by the shaft 16 acting as a tie rod and having this large reaction force in tension on the circular section located between the valve 17 and the snap-ring 22.

The advantages of this type of arrangement are great because it is possible to thus eliminate large thrust bearings. At the same time the geometry of the pump or motor is so arranged that even with a rotating valve plate and a relatively stationary cylinder barrel, the latter can align itself to the flat face of the valve plate therefore permitting working the device at minimum leakage level. The spring 44 supplies axial force to maintain the cylinder barrel 2-5 in contact with the flat face of the valve plate 10 for starting purposes. It should be noted thatthe cylinder barrel 25 is hydrostatically balanced so that the bearing force between the rotating valve plate 17 and the fiat face of stationary cylinder barrel 25 is reduced to a minimum.

The balance sleeve 51 is mounted with limited universal freedom in the pump body. itself to the flat end of the collector sleeve 18. The O- ring 52 effectively seals the high pressure oil inside the pump and at the same time does not affect freedom of alignment of the balance ring. The balance ring 51 is prevented from rotation by pin 53 preferably operative in an oversized hole. to provide freedom of alignment. The distribution of forces acting on the balance ring 15 is such that there always exists a very small positive force holding the balance ring 51 against the flat face of the collector ring 18. This positive sealing force is obtained by arranging the areas in such a way that the total forces on areas subjected to pressure and leakage pressure gradient are substantially balanced. With the unit acting as a motor the exhaust low pressure oil is discharged directly from some of the small kidneyshaped ports 46 of the cylinder barrel 25 to the inside of the pump because, as shown in FIGS. 2 and 4, only one-half of a valve plate is provided, the low pressure part being dispensed with. All the cylinder bores, positioned at an instant on the low-pressure side of the principal axis of the cam, are directly connected to the low pressure oil contained in the inside of the pump housing. The exhaust oil from the motor is then conducted from the pump housing through the port 57. This arrangement permits using a new type of rotary valve plate which carries substantial advantages over conventional designs which provided passages for conducting the low pressure (as well as high pressure) oil and therefore induced additional losses along the wav.

The anti-friction bearings 13 and 14 carry the radial component of hydraulic reaction force equivalent to motor torque. At the same time one of the hearings, in this case bearing 13, carries the additional small component of the hydraulic reaction force caused by the seal, ing surface between balance ring 15 and the flat face of the collector ring 13.

It is free to align During operation, the piston assemblies subjected to high pressure are kept in contact with the surface of the cam plate 23 by the hydraulic reaction forces, while the piston assemblies subjected to low pressure are kept in contact with the cam plate by the nutating plate 38 bodiment various modifications may obviously be made without departing from the true spirit and scope of the v invention which I intend to have defined only by the appended claims taken with all reasonable equivalents.

I claim:

1. An energy translating fluid pressure device, comprising, a housing member, a cylinder barrel member non-rotatably disposed in said housing member, said cylinder barrel member having longitudinal bores, pistons slidably mounted for reciprocation in said bores, rotatable valving means arranged to sequentially register with each of the cylinder bores, a rotatable cam plate coactable with said pistons, one of said members including an arcuate surface, the other of said members including a coactable surface contacting said arcuate surface, said arcuate surface and said coacting surface permitting universal movement between said members to align the cylinder barrel and the valve plate for sealing therebetween.

2. In the device of claim 1, said arcuate surface being on said barrel member and said coacting surface being a cylindrical surface on said housing member.

3. In the device of claim 1, keying means interposed between said members, said keying means including means to prevent rotative movement between the members and permit universal movement therebetween.

4. An energy translating fluid pressure device comprising a housing, a cylinder barrel substantially non-rotatively positioned in said housing, said cylinder barrel having a central bore, said cylinder barrel having a plurality of cylindrical bores and pistons reciprocally disposed therein, a rotary cam plate coactable with said pistons, a rotary valve plate in abutment with one end of said cylinder'barrel, said valve plate including at least one port which sequentially registers with each cylinder bore, said housing and said cylinder barrel including coacting means to permit universal movement therebetween, and rotary tie rod means journaled in said housing passing through said central bore andrigidly interconnecting said cam plate and said valve plate, said tie rod carrying in tension the axial hydraulic reaction forces developed between the' cam plate and the valve plate.

5. In the device of claim 4, said coacting means inspherical parts'adjacent said cam plate, the centers of said spherical parts lying on a plane parallel to the cam plate, said plane of the spherical parts intersecting the axisof the tie rod at a point, said point lying on a plane defined by the engagement of said arcuate surface with said coacting surface.

7. The device of claim 4 wherein said coacting means include keying means interposed between the housing and the cylinder barrel, said keying means including means to prevent rotative movement between the housing and the barrel and permit universal movement therebetween. i

' a 8. The device of claim 7 wherein the keying means includesa pin carried by said housing and a pin abutment surface on said cylinder barrel, said pin'being abuttablev against said pin abutment surface to prevent rotative movement between said housing and said barrel and permit universal movement therebetweenc 9. The device of claim 8 wherein a biasing spring is interposed between said cylinder barrel and said housing 1 and urging thebarrel axially against said valve plate.

10. The device 'of claim 4 wherein said valve plate port is kidney-shaped, and wherein said valve plate includes'a plurality of passages communicating with said cluding an arcuate surface on said cylinder barrel and a 7 coacting surface on said housing.

6. In the device of claim 5, said pistons including kidney-shaped port, said passages communicating with high pressure fluid conducting means formed in said housing.

11. In the device of claim 4, said housing including high pressure and low pressure fluid conducting means and a fluid pressure transmitting balancing ring interposed between said valve plate and said high pressure fluid conducting means, said balancing ring including a passage interconnecting said port in said valve plate and said high pressure fluid conducting means.

-12. In the device of claim;11 the provision of fluid sealing means between said balancing ring and said housing, and means interposed between said ring and said housing to substantially prevent relative rotation therebetween.

13. In the device of claim 12, said valve plate including an annular collector ring adjacent said balancing ring, said collector ring having an annular surface adjacent said balancing ring, said balancing ring including at least one annular balancing land abuttingsa'id annular face of said collector ring.

References Cited in the file of this patent 'VUNITED STATES PATENTS 2,429,806. Deschamps Oct. 28, 1947 2,608,159 Born Aug. 26, 1952 2,674,497 Dudley Apr. 6, 1954 FOREIGN PATENTS 69,346 France Dec. 27, 1952;

(Addition to No. 1,146,899)

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