US3011453A

US3011453A - Hydraulic apparatus

Info

Publication number: US3011453A
Application number: US129A
Authority: US
Inventors: Tadeusz Budzich
Original assignee: Individual
Current assignee: Individual
Priority date: 1960-01-04
Filing date: 1960-01-04
Publication date: 1961-12-05
Anticipated expiration: 1978-12-05
Also published as: GB920555A

Description

Dec. 5, 1961 T. BUDZICH HYDRAULIC APPARATUS 3 Sheets-Sheet 1 Filed Jan. 4, 1960 INVENTOR. TADEUSZ BUDZ ICH WA/%% AT TORNE Y Dec. 5, 1961 T. BUDZICH HYDRAULIC APPARATUS 5 Sheets-Sheet 2 Filed Jan. 4, 1960 V GI INVIENTOR. TADEUSZ BUDZICH A ATTORNEY Dec. 5, 1961 T. BUDZICH HYDRAULIC APPARATUS 5 Sheets-Sheet 3 Filed Jan. 4, 1960 INVENTOR. TA DEUSZ BUDZ/CH BY I ATTORNEY 3,011,453 HYDRAULIC APPARATUS V Tadeusz Budzich, 3344 Colwyn Road, Cleveland 20, Ohio Filed Jan. 4, 1960, Ser. No. 129

17 Claims. (Cl. 103-173) The present invention relates to fluid pressure apparatus and more particularly to fluid pumps and motors of axial piston type. In still more particular aspects the invention relates to axial piston pumps and motors of the type having a stationary cylinder barrel and employing a rotary cam plate and rotary valving means.

Both rotating and stationary cylinder barrel types of multi-piston axial pumps and motors are well known in the art. Both types have certain inherent advantages and disadvantages.

Hereto-fore the rotating cylinder barrel type has been characterized by high mechanical and volumetric efficiencies while working at relatively high pressures and low rotational speeds. This is mainly due to a construction in which the cylinder barrel is capable of aligning itself to a working face of a valve plate and there hydrostatically balanced with minimum mechanical losses and operable with minimum leakage. But the rotating cylinder barrel has heretofore had serious disadvantages because the rotating piston assemblies \are subjected to centrifugal force. This not only increases the bearing pressure between each piston and cylinder bore butproduces an unbalanced couple since, due to the reciprocating motion, the centers of gravity of the individual piston assemblies are spaced longitudinally from each other while rotating. This disturbs the equilibrium of the cylinder bar-rel and results in loss of efiiciency. While these disturbing centrifugal effects are small at low r.p.m., the disturbing influence is proportional to the speed squared, so that at high rotational speeds they become quite serious and require that high unbalanced loads be carried on the face of the valve plate to prevent separation of cylinder barrel from valve plate. I 1

In the stationary cylinder barrel .type of multi-piston axial pumps and motors the effect of increased bearing pressures (between piston and cylinders) and disturbing couples due to centrifugal effect are completely elimi- States Patent self-aligning cylinder barrel is stabilized by dynamic pads supporting the cylinder barrel around its full outer periphery.

Another object is to provide means biasing cylinder barrel and valve plate together for starting.

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

FIG. 1 is a longitudinal section view of a fluid pump or motor embodying the present invention; I FIG. 2 is a vertical section view taken on the line 2--2 of FIG. 1;

,. FIG. 3 shows end face of valve plate as viewed in the direction of arrows 3-3 in FIG. 2, and

FIG. 4 shows end face of cylinder barrel as viewed in the direction of the' arrows 44 of FIG. 2.

FIG. 5 shows a modified arrangement of high pressure porting of a valve otherwise as in FIG. 2;

FIG. 6 shows end face of valve plate as viewed in the direction of arrows 6-6 in FIG. 5 and FIG. 7 is a diagrammatic illustration of the principle of suspending cylinder barrel in accordance with one aspect of the present invention.

There are a number of different types of pumps and motors employing a rotating cylinder barrel in which the cylinder barrel is suspended either on the shaft or in a special bearing located between cylinder barrel and housing at 'a point in a plane perpendicular to the center line of the pump at the intersection of pump center line and a plane connecting spherical piston ends. With the rotary cylinder barrel suspended at this point, all the transverse moments induced by radial components of piston reaction force are balanced and the cylinder barrel is free to float and alignitself to the face of a stationary valve plate. But in these solutions an anti-friction beara ing of one kind or another must be introduced. Accordnated. However, a stationary cylinder barrel requires movable valving means. Movable valving means heretofore known in the art, whether of the pintle type or of the type Where an eccentrioally mounted valvingpplate oscillates across a cylinder block face, are, not of hydrostatically balanced type and either involve the use of expensive bearings or entail large mechanical losses, the volumetric and leakage characteristics of these types being inherently poor.

It is an object of the present invention to provide simple and inexpensive means for overcoming the above difficulties. I

Another object of the invention is to retain the selfaligning cylinder block characteristics of usual rotary cylinder barrel design with its advantages of high mechanical and volumetric efliciency while eliminating the parasitic effects of centrifugal force on rotating pistons by employing a cylinder barrel which is relatively stationary.

Another object is to provide a stationary cylinder barrel pump or motor with a self-aligning cylinder barrel from which all disturbing forces are eliminated so it can work at high efliciency level at substantially all speeds.

Another object is to provide an improved non-rotating cylinder barrel type of apparatus in which the cylinder barrel is free from transverse moments induced by radial components of hydraulic reaction forces.

Another object is to provide an improved rotating valve plate operable without introduction of any disturbing ing to the present invention the free-floating feature of cylinder barrel is still retained, the cylinder barrel being free to align itself to the face of rotating valve plate but, at the same time, the great disadvantages of a rotary floating point with associated heavy anti-friction bear in gs is eliminated. i

The deviceshown in the drawings will be described as a motor, although it can work just well as a pump. As shown in FIG, 1 a motor body 10 is closed at one end by a cover 11 secured as by a series of bolts 12. A driving shaft 16 is provided with internal splines 17 (as for driving a load) and is formed integral with a cam plate 23 which is rotatable with respect to the housing 10 on anti-friction bearings 24. An inner shaft 25 has one end in sliding splined engagement with the cam plate 23 and its other end in sliding splined engagement with the valve plate 26. 1 a

A relatively stationary cylinder barrel 27 works in operational engagement at one end with the valve plate I 26 and at the other end the barrel 27 is slide ably and universally mounted by a part-spherical surface 28 provided on an annular extension of the cylinder barrel. The part-spherical surface 28 of the cylinder barrel is radially located in a sleeve 29 which, in turn, is fixed tudinal bores 33' in which pistons 34 are slideably 3 mounted for reciprocation.v The pistons 34 have partspherical ends 35, and swagged over and thus universally mounted piston shoes 36 work in contact with the flat face of-the cam plate 123 and are axially constrained from leaving this flat surface by a nuta-ting plate 38. The piston shoes 36 are hydrostatically balanced in a well-known manner as by each having a recess containing high-pressure oil, and balancing lands thereabout. The high-pressure oil is conducted to the recess by a drilling through each shoe 36 and by'longitudinal drillings 39 along the center lines of the pistons 34.

The cylinder barrel 27 with its annular extension equipped with part-spherical surface 28 is universally mounted with respect to the reaction sleeve 29 at a point or along a peripheral line lying in a plane passing through the point of intersection of a plane connecting the centers of the spherical piston ends 35' with the center line of the cylinder barrel and its coaxial extension.

A compression spring 46 has one end located in a recess provided in the pump body 10 and has its other end engaging a fiat end surface of the annular extension of the cylinder barrel 27.

At the opposite end of the cylinder barrel 27 a flat surface thereof works in operational contact with the valve plate 26 and is, as is shown in FIG. 4, equipped with a series of kidney-shaped slots 46. sequentially brought into register with the individual slots 46 are valve plate slots 47 and 68 (see FIGS. 2 and 3).

Slot 47 is a high pressure kidney-shaped opening having a counter-part at the opposite side of the valve plate and these slots communicate with plural axially extending drillings 49 which in turn communicate with radial drillings 56 for establishing communication from the high pressure valve port 47 to a valve plate central cavity 51 and in turn with a collector ring 52 and a high pressure port 53 which, for motor operation, is the point at which pressure fluid is introduced to the device.

Meanwhile the low pressure valve plate slot 48 communicates through radial drillings 55 with an annular space within the housing and outside the valve plate and cylinder barrel and in turn with a low pressure port 56 which, for motor action, takes care of the discharge fluid and for pump action provides the inlet oil.

As will be seen in FIG. 2, the radial drillings 50' may be sealed off with screw plugs 57 and the central passage 51 may be a drilling later sealed off with a screw plug 53, and the valve plate has a portion journalled with respect to the housing cover 11 on either side of the rotating and stationaryportions of the collector ring 52.

Referring to FIGS. and'6, a modification is shown in which the valve plate is not directly journalled in the end cover 1-1. In FIG. 5, like parts are like numbered as in FIG. 2, while a central drilling 61 terminates at one end in the valve plate flat face adjacent the cylinder barrel, and at the opposite end terminates in a valve plate flat face against which a balance sleeve 62 works in operational engagement while held thereagainst initially by a spring 63 and sealed with respect to the cover 11 by an O ring 65. A balance cap 66 is connected to a balancing piston 67 by a stem 68 which passes through the cam plate central drilling 61 and through the balance sleeve 62 which affords communication from a space 69 communicating with the high pressure port 53. Balancing piston 67 is shown secured to stem 68 by a nut 71 and operates in a balancing cylinder portion 72 provided in cover 11. Cap 66 has a face 73 engaging the flat face of the valve plate. A cam plate drive sleeve 74 is caused to rotate the cam plate through a pin- 75 while secured to a driving shaft 76 through a pin 77. At its opposite end shaft'76 may be provided with a spline for engaging the cam plate. If desired, the piston 67 may be provided with a sealing ring 78 to prevent leakage of high pressure to atmosphere.

Some liberties have been taken in the drawing for reasons of clarity of demonstration and those in the art will understand that there will usually be an odd number of pistons, as indicated by the number of slots 46 in FIG. 4, and not an even number of pistons, the section of FIG. 1 showing pistons at positions of maximum and minimum displacement merely for the sake of demonstration, andthe sections i'of FIGS. 2 and 5 showing apparently 180 opposite cylinders merely in order to correspond with FIG. 1.

Operation of the unit The operation of the unit may be described as that of a high-pressure motor. The housings cylinder barrel mounting sleeve 29 acts as a circular reaction ring permanently retained in the pump housing It). The cylinder barrel 27 with its annular extension equipped with a part-spherical surface 28 is universally mounted with respect to this reaction ring 29' preferably at a point or along a peripheral line lying in a plane passing through the point of intersection of a plane connecting the centers of the spherical piston ends with the center line of the cylinder barrel and its annular extension. The cylinder barrel 27 is prevented from rotation (about its own axis) by pin 36 which engages hole 31 which is made substantially oversize so that it doesnt impair the freedom of alignment of the cylinder barrel 27. The flat face of the cylinder barrel 27 works in operational contact with a fiat face of the valve plate 26 which is rotationally connected through the shaft 25 with the cam plate 26. The cylinder barrel 27 retains the slideable pistons 34 which work in operative association, through piston shoes 36, with the cam plate 23.

In FIGS. 2 and 5 alternative arrangements of valve plate have been shown, but for the device tooperate as a motor, the arrangement of FIG. 5 is preferable,and operation with this arrangement will be the operation primarily described.

For motor operation, high pressure fluid is introduced through port 53 to chamber 69, through sleeve 62, central passage 61, radial drillings 50, valve plate kidney slot 47, to passages 46 (for those of the cylinders to be subjected to high pressure), cylinder bores 33, and pistons 34. In FIG- 5, the space 61 is shown closed at one end by the cap 66 and on the other end by the balancing piston 67. The, balancing sleeve 62 Separates the highpressure oil from the low-pressure zone communicating through passages 55 ultimately with the low-pressure port 56. This construction provides a valve which is free to align itself with the flat face of the pump cover and with the flat face of the cylinder barrel, all of the forces resulting from introduction of high-pressure oil to the valve plate being eliminated by balancing. Thus the pressure acting on balancing piston 67 induces a force carried by the stem 68 to cap 66 which has a flat surface73 working in operational contact with the valve plate, with the eifective area of 73 (depending on leakage gradient) and the effective area of cap 66 subjected to oil and the effective surface of the balancing piston 67 so selected and arranged that the net force maintains the valve plate in a state of equilibrium. Areas such as 64 and 73 are so proportioned so that a small portion of the force supplied, by the piston 67 in the case of area 72, and by the sleeve 62 in the case of area '64, positively maintains the cap 66 and balancing sleeve 62 in contact with the valve plate 26, thus sealing the high-pressure oil. The spring 63 anchored at one end to the pump or motor cover and at its other end bearing on a portion of the sleeve 62 maintains the balancing sleeve 62 in contact with the valve plate for starting. Ordinarily the

parts

66, 62 and 67 because of the magnitude of sliding forces will remain rotatively stationary, although these parts can rotate without any detrimental effect. All three are free to slide axially the amount required while the valve plate 26 is driven from the driving sleeve 74 and shaft 76 and the sleeve 74 by its engagement with the walls of a central passage 79 in the cylinder barrel maintains the radial alignment of the valve plate 26.

High-pressure fluid from the port 53 is introduced through the valve plate kidney 47 to the slots 46 leading to the cylinder bores located on one side of the principal axis of the cam plate 23. Such acarn principal'axis is an imaginary center line passing along the greatest'inclination of the cam surface and through its center of rotation and for the showing of FIG. 1 it may be assumed that the cam principal axis lies in the plane'of the drawing. Accordingly, pistons to one side of the principal axis of the cam urge their piston shoes against the inclined plane of the cam plate and induce a rotary moment in the cam plate which will cause it to revolve while supported by the anti-friction bearings 24 and this rotation will be transmitted through the

spline shaft

25 or 76 and through sleeve 74 (FIG. to the valve plate 26, providing a continuous rotary motion of cam plate while the low-pressure exhaust oil from cylinders located on the opposite side of the cam principal axis is directly discharged to the space 48 of the valve plate and through drillings 55 to the inside of the pump housing outside the cylinder barrel and valve plate balancing lands and through the low pressure port 56.

Hydraulic reaction acting on the cylinder barrel 27 is transferred to the valve plate 26 in conventional manner well-known to the art so that only a fraction of the total reaction force is transferred to the valve plate as contact pressure. both the port 48 and the kidney-slot 47 on the front face of the valve plate find their equal equivalents on the back-side of the valve plate. In this Way, the very small forces necessary for sealing are carried onlyon the flat faces of the valve plate, the valve plate being maintained in a state of equilibrium.

VJith the arrangement of FIG. 2, however, although the front and back faces are again balanced, the highpressure oil is introduced from port 53 through the col lector ring 52 and through the central passage 51 and radial passages 50, axial drillings 49, and arcuate slots 47, on both faces of the valve plate. So that the leakage of pressure around the outside of the annular extension of the valve plate will not build up and in the end space 59, and thereby cause an unseating of valve plate, this space 59 is preferably ported back to the low-pressure space around the cylinder barrel by means of drillings or piping not shown, except as in FIG. 1.

The cylinder barrel 27 is relatively stationary and is mounted with respect to the housing on the part-spherical surface 28 in contact with the ring 29 with these surfaces so positioned, as shown in FIG. 7, that a plane cc through the centers of the spherical piston ends intersects the axis aa of the pump or motor at the same point as a plane bb substantially through the center of the partspherical surface 28 intersects the axis a-a of the pump or motor. Preferably, too, the radius R of the partspherical surface 28 finds its center at this same point of intersection of axis of machine with a plane passing through the centers of spherical piston ends so that the pistons to one side of the vertical have their reaction forces Fr (exerting a clock-wise moment around the aabb intersection) balanced out by pistons at the other side of bb exerting a counter-clockwise moment. Thus it is possible to use a relatively stationary cylinder barrel while having transverse components of piston reaction forces completely eliminated while the cylinder barrel is still capable of free-floating for aligning itself against a flat face of the valve plate.

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 freely align itself to the flat face of the valve plate therefore permitting working the device at minimum leakage level.

Free rotation of the cylinder barrel is prevented by the pin 30 which, as shown, engages an oversize hole in the cylinder barrel annular extension.

Since the cylinder barrel 27 is constrained from rotation by the pin 30, the full torque (proportional to the I hydraulic reaction force and the angle of inclination of the cam plate 23) will be transmitted to rotate the cam It should be observed that in the valve plate plate 23, and therefore to rotate shaft 25 (or 76) and valve plate 26. V

Thus the whole arrangement is such as to cause a minimum of mechanical and volumetric losses While permitting the cylinder barrel to align itself to the valve plate and the valve plate with its balanced back face to carry the reactive loads, while high-pressure oil is introduced through the valve plate in such way as to cause no disturbing forces which wouldupset this equilibrium, and the advantages usually associated with rotating cylinder barrel type pumps are provided in a type of pump having a relatively stationary cylinder barrel.

While I have illustrated and described particular em bodiments, various modifications may obviously be made without departing-from the true spirit and scope of the 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, 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 portwhich sequentially registers with each cylinder bore, said housing and said cylinder barrel including coacting means to permit universal movement therebetween, and

drive means extending through said central bore drivingly interconnecting said valve plate and said cam plate, said drive means slidably engaging at least one of said plates, whereby the axial hydraulic reaction forces on said plates are carried by the housing member.

2. In a device of claim 1, a pin carried by said housing and a pin abutment surface on said cylinder barrel, said pin being abuttable against said pin abutment surface to prevent ro'tative movement between said housing and said barrel and permit universal movement therebetween.

3. In the device of claim 1, said coacting means including an arcuate surface on said barrel and a c'oacting surface on said housing engaging said arcuate surface, said pistons including spherical 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 axis of the drive means at a point, said point lying on a plane defined by the engagement of said arcuate surface with said coacting surface.

4. In the device of claim 1, wherein there is an axially extending clearance radially between the drive means and the cylinder barrel, and at least one spline drive means interconnecting the cam plate through the drive means to the valve plate for driving the valve plate through said clearance to permit freedom of alignment of the parts.

5. A device as in claim 1 further characterized by said drive means including a shaft, the cam plate device being connected to said shaft through a spline to permit axial movement of one with respect to the other, a driv ing sleeve connected to rotate with said shaft and radially constrained within the cylinder barrel, and a connection between said sleeve and valve plate to rotatethe valve plate While providing radial location thereof with respect to cylinder barrel.

6. A hydraulic pump or motor device having an outer housing, a substantially non-rotatable cylinder barrel, a part-spherical surf-ace provided on one of said parts for universally mounting the barrel with respect to the housing, pistons arranged for reciprocation in said cylinder barrel, a rotatable cam plate positioned at one end of said cylinder barrel, a rotatable valve plate positioned at the opposite end of said cylinder barrel, a shaft connecting the cam plate and the valve plate so that one may effect rotation of the other, said valve plate having one flat face in contact with the cylinder barrel and an opposite flat face in contact With a portion of the housing, said valve plate having kidney-shaped ports disposed equally on the two fiat faces and a central passage extending between said flat faces, and having radially extending passages interconnecting said central passage with the kidney-shaped ports on both faces whereby high-pressure fluid may be readily transmitted between the central passage and the kidney-shaped ports.

7. A device as in claim 6 further characterized by a cap sealing the central passage of the valve plate at the end thereof in contact with the cylinder barrel, a stem. for said cap extending through the valve plate central pas- .sage, and a piston subjected to high pressure and connected to said stem to urge said cap against said one valve plate face.

8. A device as in claim 7 further characterized by a balancing sleeve arranged about said stern and operable against the face of the valve plate in contact With the housing, and means conducting high-pressure oil to force said sleeve against valve plate for sealing the central passage with respect to the housing and to cause the pieton to urge the cap against the valve. plate for sealing the central passage at the opposite end.

9. A device as in claim 8 further characterized by the balancing sleeve, piston and cap being configured and arranged so that during normal operation the balancing sleeve provides against the valve plate a force equal and opposite to that exerted by the piston and the cap on the opposite side of the valve plate.

10. A device as in claim 9 further characterized by the cap having a face operating against said one face of the valve plate to provide a leakage pressure gradient balancing a portion of the force exerted on the piston while a small remaining force biases the cap against the valve plate. 1

11. A device as in claim 10 further characterized by the balancing sleeve having a face in contact with said opposite valve plate face so arranged that a force acting on the cross-section area of the balancing sleeve is counter-balanced by pressure gradient distribution between said faces with a remaining small force maintaining the, sleeve in contact With said opposite valve plate face thus preventing appreciable leakage.

12. A device as in claim 10 further characterized by a compression spring interposed between the balancing sleeve and a portion of the housing and for maintaining the sleeve against the valve plate for starting purposes.

13. A device as in claim 9 further characterized by the housing having a high-pressure port leading through a cavity in the housing into a collector ring chamber formed about the cap stem between the sleeve and the piston.

14. A device as in claim 13 further characterized by the valve plate having a body extending about a central axis but relieved at one portion to provide substantially direct communication for low-pressure fluid.

15. A device as in claim 14 further characterized by th valve plate being relieved to provide an arcuate space which communicates with the pistons at low pressure, and the valve plate having an outer ring portion with radial drillings about said space and for providing communication with the interior of the housing about the cylinder barrel, and the housing having a low pressure port communicating with said space about the cylinderv barrel.

16. A device as in claim 6 further characterized by the valve plate having onefiat face adjacent the cylinder barrel and an opposite flat face interrupted by a central cylindrical portion extending beyond said second face and having an internal passage in communication with a collector ring communicating with a high-pressure inlet passing through a portion of the housing, and said valve plate having radial drillings communicating between said central passage and arcuate passages in both faces.

17. A device as in claim 16 further characterized by the shaft being splined at one end to slide with respect to the cam plate and splined at the other end for making sliding engagement with the valve plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,971,601 Dilg Aug. 28, 1934 2,534,153 Widmer Dec. 12, 1950 2,608,159 Born Aug. 26, 1952 2,674,197 Dudley Apr. 6, 1954 FOREIGN PATENTS 69,346 France May 27, 1958 (1st addition to No. 1,146,899) 1,120,346 France Apr. 16, 1956