GB2268779A

GB2268779A - Reduced sized rotary hydraulic motor.

Info

Publication number: GB2268779A
Application number: GB9316672A
Authority: GB
Inventors: Jr Hollis Newcomb White
Original assignee: WHITE HOLLIS NEWCOMB JUN
Current assignee: WHITE HOLLIS NEWCOMB JUN
Priority date: 1990-01-29
Filing date: 1993-08-11
Publication date: 1994-01-19
Anticipated expiration: 2010-07-12
Also published as: GB2268779B; GB2275084B; GB9404872D0; GB2275084A; GB9316672D0

Abstract

In a motor of the gerotor type passages 71 in a swirl plate 29 have intermediate portions which are further from the centre of the plate than are the ends of the passages. The passages 71 communicate between value openings (70, Fig 8) in a valving plate 28 and cell openings (72, Fig 10) in a cell opening plate 30. The orbiting valve of a valve assembly 27 is connected to a wobble stick 34 for rotation therewith, the orbiting valve being non-circular with discrete valving openings (61, Figs 13 and 16) formed therethrough to define an inner valve opening and notches (62) formed in its circumference to define an outer valving opening formed by the enlarged circumferential surface. The units 34, 35 adjacent the valve assembly each comprise a number of ported plates brazed together. <IMAGE>

Description

REDUCED SIZED HYDRAULIC MOTOR This invention relates to a reduced sized hydraulic pressure device.

Background of the Invention Historically hydraulic pressure devices have been large, weighty units designed to provide low speed, high torque in applications remote from a central power source. The U.S.

Patents 3,606,601 and 4,697,997 are examples of these heavy duty hydraulic motors. These heavy duty hydraulic motors are of a significant size and weight. The size and weight limits the number of potential applications for the hydraulic pressure devices. This limits the utilization of such devices.

Objects of the Invention It is an object of this present invention to provide for a reduced size hydraulic motor.

It is an object of this invention to provide for a high torque device in a small package.

It is an object of this present invention to increase the potential applications for gerotor motors.

It is an object of this invention to reduce the cost of gerotor motors.

Other objects and a more complete understanding of the invention may be had by referring to the drawings in which: Drawings Figure 1 is a longitudinal cross sectional view of a pressure device incorporating the invention of the application; Figure 2 is a lateral cross sectional view of the port plate for the hydraulic device of Figure 1; Figure 3 is a lateral cross sectional view of the first fluid passage plate of the device of Figure 1; Figure 4 is a lateral cross sectional view of the second passage plate of the device of Figure 1; Figure 5 is a lateral cross sectional view of the transfer plate of the device of Figure 1; Figure 6 is a lateral cross sectional view of the commutation plate of the device of Figure 1; Figure 7 is a lateral cross sectional view of the orbiting valve of the device of Figure 1;; Figure 8 is a lateral cross sectional view of the valving plate of the device of Figure 1; Figure 9 is a lateral cross sectional view of the swirl plate of the device of Figure 1; Figure 10 is a lateral cross sectional view of the opening plate of the device of Figure 1; Figure 11 is a lateral cross sectional view of the gerotor structure of the device of Figure 1; Figure 12 is a lateral cross sectional view of the mounting piece of the device of Figure 1; Figure 13 is a lateral cross sectional view of the orbiting valve located on top of the commutation plate taken generally from line 13-13 in Figure 1; Figure 14 is a view of the orbiting valve on top of the valving plate of Figure 8 taken generally from line 14-14 in Figure 1; Figure 15 is a view of the gerotor device on top of the cell opening plate of Figure 10 taken generally from line 15-15 in Figure 1;; Figure 16 is a conceptual drawing detailing the cooperation and shape of the orbiting valve; Figure 17 is an enlarged drawing of a section of Figure 16; Figure 18 is a drawing of a representational prior art orbiting valve; Figure 19 is a cross-sectional drawing of the wear plate 39; and, Figure 20 is a cross-s.ectional drawing of an alternate wobble stick having oversized teeth.

Description of the Drawings This invention relates to a reduced size pressure device. The invention will be described in its preferred embodiment of a gerotor motor having an orbiting valve separate from the rotor.

The gerotor motor 20 has a body including a port plate 22, first and second passage plates 23 and 24, a transfer plate 25, a commutation plate 26, an orbiting valve structure 27, a valving plate 28, a swirl plate 29, a cell opening-plate 30, a gerotor structure 31, a mounting piece 32, a drive shaft 33, and a wobble stick 34.

The port plate 22 interconnects the motor 20 to the pressure and return lines through ports 40, 41 and connects the interior of the motor 20 to a drain line via the port 42. The port plate 22 itself is brazed together with the two passage plates 23, 24, the transfer plate 25, and the commutation plate 26 in order to form an integral, single piece assembly 34.

Small pins 43 through a series of three alignment holes 44 in each of this series of plates aligns the plates into their correct orientation in respect to the other plates in order hQ ease the assembly and brazing of this unit 34. An orientation bump 45 on each of the plates further facilitates the assembly process.

The port openings 40, 41 extend through the port plate 42, the first passage plate 23, and the second passage plate 24. These openings are tapped after the unit 34 is brazed together. This allows for a solid connection of the pressure and return lines for the gerotor device in a minimum space (i.e. not adding any longitudinal length). The case drain 42 likewise extends through all three plates and is tapped in a similar manner. The port plate and passage plate therefore together retain the fluid pressure, return, and drain lines to the motor 20. If desired another method of connecting these lines could also be utilized (such as additional already threaded external taps brazed directly into the untapped openings or otherwise).

The transfer plate 25 fluidically connects the ports 40, 41, 42 in the port plate 22 to the respective openings in the commutation plate 26. The passages in the transfer plate 25 accomplish this synergistically with the commutation passages in the commutation plate 26. The fluid from the port 41 interconnects with one of the passages 50 in the transfer plate 25. There are walls 53 between and around each of these passages 50 separating them from each other. The commutation passages 55 in the neighboring commutation plate 26 overlay the passages 50 in the transfer plate 25 so as to interconnect the otherwise separated passages 50 (and visa versa).The commutation passages 55 in the commutation plate allow fluid to pass between the passages 50 in the transfer plate 25 over the walls 53 and the passages 50 in the transfer plate 25 in turn allow fluid to bypass the walls 54 between the commutation passages 55 in the commutation plate 26. In a like manner the fluid from the port 40 interconnects to the passages 51 in the transfer plate 25. Again the wall portions 58 between the passages 51 in the transfer plate are bypassed by the commutation passages 56 in the commutation plate and the walls 59 in the commutation plate 26 are bypassed by the passages 51 in the transfer plate. The use of the passages in one plate to bypass walls between passages in another plate allows fluid to flow in a manner as if the walls were not there while also locating the passages (and other parts of the plates) into a reliable and predictable location. Thus the operation and construction of the device are both facilitated at the same time.

In addition to these synergistic overlaying passages, there is a passage 52 in the transfer plate which interconnects the drain port 42 to a hole 57 in the center of the commutation plate 26. This hole 57 interconnects to the interior of the motor 20 as later described. Note that the passages 50, 51, 52, 54, 55, and 56 are located asymmetrically on the transfer plate and commutation plate. This asymmetric location or orientation allows for passages to occupy the same radial space as other passages in order to reduce the overall diameter of the device while providing at the same time for an efficient fluid transfer between these passages and operation of the device.

The commutation passages 55, 56 in the commutation plate 26 communicate at all times with the area 63 surrounding the orbiting valve 60 and a groove 66 cut on the back side of the rotor 60 which groove is in turn interconnected to the four inner valving openings 61 for the device. This connection allows for communication of fluid from the ports 40, 41 to the two valving openings 61, 62 in the orbiting valve. In addition the central drive opening 64 of the orbiting valve 60 communicates with the hole 57 in order to connect such central drive opening 64 to the opening 57 in the commutation plate 26.

This latter connection provides the fluidic transfer path for the case drain from the interior of the gerotor motor 20.

In the preferred embodiment fluid is fed into this interior in order to cool and lubricate the bearings and wobble stick drive interconnections. This fluid begins in the periodially pressurized swirls 71 in plate 29, travels down the bolt holes 80 (about the.bolts 81) to a circular groove 82 cut s into the interior of the mounting plate 32 radially outward of the main thrust bearing. As this fluid is pressurized (during the selective valving to the gerotor cells), the fluid then passes through the radial thrust bearing into the interior of the mounting plate and eventually through the central drive opening 64 and the hole 57 to exit the device through port 42.

(As the central drive opening 64 is held at a low pressure, there is no significant reverse flow back down the bolt holes 80 (via the particular swirl(s) connection to return instead of pressure.) If desired a separate valved flow of high pressure could be provided.

The orbiting valve 60 is the main operative valve for the gerotor motor 20. This orbiting valve 60 seen in Figure 7 includes a series of four inner valving openings 61 and a series of four outer valving notches 62. These inner openings and valving notches cooperate with a series of five valving openings 70 in the valving plate 28 in order to valve the device. This four valving opening, five cell (and fewer openings/cells) device is the preferred environment for the invention.

The shape and design of. the orbiting valve 60 is unique. In a normal toe driven orbiting valve (similar to that shown in the U.S. Patent 3,606,601), the orbiting valve 100 is circular in shape with even diameters throughout the valve and continuously extending valving openings (the inside 102 and outside 103 edges of the main valving section 101). The normal orbiting valve is also free to rotate in respect to the wobble stick. This is shown in representative form in Figure 18.

In contrast the preferred orbiting valve 60 of this application has a series of discreet hat shaped inner openings 61 and is connected to the wobble stick for rotation therewith.

In addition, a series of discreet recessed notches 62 improves the outer opening valving operation. The shape of the openings 61 are determined by generating the path traced by a particular salving opening 70 in respect to a moving valve 60. (This design is what one would see the opening 70 follow if one was standing on the orbiting valve 60 during a 3600 valving peration.) As shown in Figures 16 and 17 the hat shaped inner opening 61 is laid out in a pattern matching that followed by the valving opening 70 (instead of extending for 3600 as in the representative orbiting valve of Figure 18). The outermost extension 65 of the opening 61 (the top of the hat) is radially outward of that in an ordinary orbiting'valve. This increase the surface area of valving fluid passages between the opening 61 and valving opening 70.Note that the main section 69 of the hat shaped opening 61 is slightly oversized in an inward and circumferential direction - i.e. bigger than the valving opening 70. This provides a measure of tolerance to the valving of the device. The curved cutouts 63 in the top of the openings 61 are designed so as to allow a minimal null position wherein the particular valving opening 70 is connected to neither the opening 61 or the notch 62 (null opening identified as the dotted lined opening 78 in Figure 17).

There is an increased spacing between the opening 70 with the opening 61 and the notch 62 in a diagonal direction as contrasted to that in a radial direction (i.e. almost no spacing in a radial direction with about three thousandths spacing in a diagonal direction). This increased spacing is designed to minimize direct leakage between the opening 61 and notch 62 by approximately equalizing both the radial and diagonal sealing time (as opposed to equalizing the radial and diagonal distances). Note that the inner openings 61 defined in Figures 16 and 17 are separately, individually located radially spaced about the parameter of the orbiting valve 60.

It is preferred that a groove 64 on a surface of the valve 60 (preferably the backside) interconnect the openings 61 (groove 64 omitted in Figure 13 for clarity). This groove increases the commutation fluid flow to the openings 61 by effectively combining their surface area for commutation. This is needed with the asymmetric commutation shown. With other types of commutation, the groove would be an added feature.

The notch 62 is cut inwardly into the outer circumference of the orbiting valve 60 for two reasons. The leading and trailing triangles 66 (dotted lines) are cut into the circumference 68 of the valve 60 in order to improve the valving to the outermost valving opening. The inner crescent 67 is cut into the valve 60 in order to create a clearance for the bolts 81 that hold the device together. This in combination with the valve 60 being keyed to the wobble stick allows the orbiting valve 60 to be oversized in respect to the remainder of the device. This facilitates the accuracy of the valving.

Note that due to the shapes of the opening 61 and the notch 62 the valving opening 70 is connected to each for substantially the same length of time due to the circumferential extension of the opening 61 and notch 63 differing. This increases the smoothness of the power generated by the device.

The valving plate 28 cooperates with the swirl plate 29 and the cell opening plate 30 in order to accomplish the offset needed for the type of orbiting valving utilized in the gerotor motor. These three plates 28, 29, 30 are brazed together to form an integral assembly 35. In this assembly each hole 70 in the valving plate communicates through the swirl 71 in the swirl plate 29 to interconnect with a cell opening 72 in the cell opening plate 30. The number of these passages is equal to the number of gerotor cells in the gerotor device 31, in this case five in number. The shape of the openings 70 is unusual for their slightly elliptical shape.

This shape allows one to maximize the radial valving dwell time while reducing the radial dimension of the device slightly mor than an equivalent circle would do. The shape of the passages 71 in a swirl plate 29 are unusual in that these passages swirl outwards around the bolts 81 and then back inwardly to the approximate location of the cell openings 72 in the plate 30.

The actual shape of these passages 71 are dictated more by the geometry of the valve 60 and the cell openings 72 than any other factor. In specific the ends of the passages 71 match the shapes of the valving openings 70 in the valving plate 28 and the cell opening 72 in the cell opening plate 30 with the -length between these two ends being designed to have a minimum wall thickness between adjacent or overlaying passages. This allows one to maximize the fluid flow through these swirls 71 for the particular dimensions shown and described. The cell openings 72 in the cell opening plate 30 have a geometry largely dictated again by ,the remainder of the device. For example the outer edges 73 of the openings 72 are designed to allow the swirls 71 in plate 29 to bypass on the inside of the bolts through such plate.An additional example the inside 74 of the cell openings 72 are designed to allow for a clearance of the wobble stick drive on the inside of the rotor so as to insure a separation between the case drain and the openings 72.

The width of the cell openings 72 are designed as a compromise between the desire to have the passages 71 as large as in cross section as possible while also insuring that there is a good flow path through such passages 72.

The plates 28, 29, 30 are connected into an assembly 35. As with the assembly 34 there are a series of locating pins 75 in a series of holes 76 in order to align these plates into position prior to and during brazing assembly. Again a nub 77 on the outside of the plates provides external verification that the plates are located in their proper orientation.

The gerotor device 31 is a relatively standard gerotor device with the exception of the fact the preferred rotor is driven by a heavy, equal number-toothed wobble stick 34 having teeth in alignment with the lobes of the rotor. The rotor lobes thus allow room for the teeth of the wobble stick without significant compromise. In the embodiment shown, the outside diameter about the rotor end teeth of the wobble stick is the maximum integral size that can fit through the circular drive hole in the wear plate. This diameter was determined in consideration primarily of the size of the circular hole, the thickness of the wear plate, the number of teeth, the root diameter of the teeth, and the thickness of the teeth.An alternate way of' obtaining oversized teeth at the wobble stick rotor drive interconnection would be to use a two piece wobble stick (see for example Figure 20--two piece construction 200, 201 with a multiple spline 202 interconnection). The alternate method would allow even larger teeth for the wobble stick rotor drive interconnection shown at a added materials/assembly cost.

In certain very high torque applications these even larger teeth would be beneficial. Other construction methods to allow oversized teeth could also be utilized as appropriate (multiple piece wear plates, laminated wear plates, pass through notches in the wear plate--later filled or unfilled, separate wobble stick teeth, etc.). In any event it is preferred that the maximum outside diameter about the wobble stick teeth be substantially equal to or greater than the root or minor diameter (minimum diameter) at the base of the rotor's lobes.

This in combination with the fact that the wobble stick teeth are in alignment with the rotor lobes allows for a greater strength to the wobble stick construction rotor drive interconnection. The drive shaft end teeth of the wobble stick are similarly oversized. However there are fewer design constraints on these teeth than those in the rotor.

The rotor 35 of this gerotor device cooperates with the surrounding stator 36 in order to form expanding and contracting gerotor cells 37. The stator rolls for the stator rotate on a thin film of oil to ease this operation. It is preferred that the rotor 35 be slightly oversized in respect to the geometry of the stator 36 so as to force these rolls outward during the operation of the gerotor device 31. This outward force increases the quality of the seal for the gerotor device and thus improves the efficiency of'such device. The openings in the center of the rotor about the wobble stick 34 allow fluid from the interior of the gerotor device 20 to pass down the length of the opening 79 in the assembly 35 to interconnect to the openings about the valve drive 64 and thus interconnect to the hole 57 and port 42 in the port plate.

This provides for a drain passage for the interior of the gerotor device 20 allowing the fluid therein to escape the device.

The mounting piece 32 is utilized to retain the gerotor motor 20 in operative position in respect to the device with which it will be utilized. A series of bolts 80 extend from this mounting piece through the gerotor structure 31, the assembly 35, and the valving plate to interconnect with the threaded holes 81 in the assembly 34. This series of bolts 80 retains all of the pieces together to form the integral housing for the gerotor device 20. Due to the fact that the heads of the bolts 80 are recessed, mounting of the gerotor motor 20 is not compromised. If desired these bolts 80 could extend through the device 20 in the other direction with the threads in the mounting piece 32, be terminated differently (a nut) or otherwise modified to suit a particular application.

Separately tapped holes extending between and parallel to the bolts 80 allow for the mounting of the particular motor shown.

Other methods could also be utilized as appropriate.

The drive shaft 33 is the output for the gerotor device 20. In the preferred embodiment this drive shaft is of a significant diameter in respect to the size of the remainder of the gerotor device. This size is due to the recognition of the tremendous torque which is capable of being generated by this reduced size gerotor device as well as the five to one speed reduction inherent in the gerotor structure. If desired other forms of drive output could be utilized. An example of this would be to bolt the gerotor structure itself from the wear plate 39 through the port plate 22 directly onto the device being powered with the wobble stick 34 extending into the device to directly power an internally splined shaft for the device (instead of the intermediate drive shaft 33).

Therefore, although the invention has been described in its preferred form with a certain degree of particularity it is to be understood that numerous changes can be made without partinc from the invention as hereinafter claimed. For example the inner valve openings 61 shown are four discreet holes located at the operative positions necessary for inner valving openings. If desired a groove could be cut on, the face of the valve 60 interconnecting these holes (in a pattern recognizing the cooperation with the holes 70 to valve the device). 'One such groove 60 is shown in dotted lines in Figure 14. This groove would allow fluid to pass on both sides of the valve to the operative opening(s). Other modifications could also be made.

Claims

1. In a gerotor hydraulic pressure device having a series of swirls between valving openings and cell openings, which swirls compensate for the angular placement of an orbiting valve in respect to the cells, the improvement of the swirls extending radially outward and then inward to connect the valving openings with the cell openings respectively.

2. In a gerotor hydraulic pressure device having a wobble stick toe driven orbiting valve with input and output commutation thereto , the improvement of the input and output commutation to the orbiting valve being asymmetrical.

3. In a gerotor hydraulic pressure device having a wobble stick with teeth drivingly engaging a rotor, the improvement of the teeth of the wobble stick being laid out in the pattern of the lobes of the rotor.

4. In a gerotor hydraulic pressure device having a wobble stick with teeth having an outside diameter drivingly engaging a rotor having lobes with a minor diameter, the improvement of the outside diameter of the wobble stick teeth being at least equal to the minor diameter of the rotor lobes.

5. In a gerotor hydraulic pressure device having bidirectional cell openings in the body of the device and a wobble stick driven rotor , the cell openings having an inner edge and the wobble stick having teeth which trace a pattern on the surface containing the cell openings, the improvement of the inner edge of the cell openings being laid out in a pattern so as to avoid the areas traced by the teeth of the wobble stick.

6. A gerotor hydraulic pressure device comprising a first plate, a first set of passages, said first set of passages being laid out in said first plate, said first set of passages being interrupted by walls, a second plate, a second series of passages, said second set of passages being laid out in said second plate, said second series of passages being interrupted by walls, and at least one of said wall of said first set of passages being displaced from at least one of said walls of said second set of passages so as to allow fluid flow between said passages about said walls respectively.

7. In a gerotor hydraulic pressure device having bolts and a toe driven valve orbiting in an opening, the valve having an outer circumference, the improvement comprising the bolts protruding into the opening, the valve being connected to the toe for rotation therewith, crescents, and said crescents being in the outer circumference of the valve allowing clearance for the bolts.

8. In a gerotor device having an orbiting valve and valving openings, the improvement of the valving openings being laid out in an ellipse so as to equalize radial and diagonal sealing time.

9. In a gerotor device having bi-directional alternately pressurized passages, closed centre valving, and a separate case drain, the improvement of a hole, and said hole interconnecting a bi-directional alternately pressurized passage to the isolated centre case of the gerotor device so as to circulate cooling and lubrication fluid therethrough.

10. In a gerotor device having a case, closed centre valving with an opening in the valve, an improved case drain comprising means to drain the case, said means to drain the case including the opening in the valve.

Il. In a gerotor hydraulic pressure device having a rotor with a separate wobble stick toe driven orbiting valve, the orbiting valve having an inner and outer opening that cooperate with bi-directional passage valving openings in the body of the device to valve the device, the improvement comprising the orbiting valve being connected to the wobble stick for rotation therewith and the inner valving opening being divided into a set of discreet openings.

12. The gerotor pressure device of Claim 11 wherein the valve has a commutation surface and characterized in that the set of discreet openings are interconnected by a channel on the commutation surface.

13. The gerotor pressure device of Claim 11 wherein the outer opening is a circumference of the valve and characterized by the addition of a series of triangle notches, and said series of triangle notches being in the outer circumference of the valve to increase the surface area of the valving between the outer opening and the valving opening.

14. The gerotor pressure device of Claim 11 wherein the orbiting valve has an outer circumference and orbits in an area having protrusions and characterized by the addition of a series of clearance crescents, and said series of clearance crescents being in the outer circumference of the valve so as to provide clearance for the protrusions.

15. The gerotor pressure device of Claim 14 characterized in that said series of clearance crescents directly adjoin said series of triangle notches so as to be integral therewith.

16. The gerotor pressure device of Claim 11 wherein the valving opening has a radial dimension and characterized in that the inner opening includes a radially outward section, and said radially outward section being radially spaced from the outer opening by less than the radial dimension of the valving opening.

17. The gerotor pressure device of Claim 16 wherein the outer opening is a circumference of the valve and characterized by the addition of a series of triangular notches, and said series of triangular notches being in the outer circumference of the valve to increase the surface area of the valving between the outer opening and the valving opening.

18. The gerotor pressure device of Claim 17 wherein the valving opening has a diagonal dimension and characterized in that the inner opening is diagonally spaced from the outer opening by at least the diagonal dimension of the valving opening.

19. In a gerotor hydraulic pressure device having a rotor with a separate wobble stick, toe driven orbiting value, the orbiting valve having inner and outer openings that cooperate with bi-directional passage valving openings in the body of the device to valve the device, the valving openings having a dimension, the outside edge of the inner valving openings extending a first distance from the centre of the valve and the inside edge of the outer valving openings extending a second distance from the centre of the valve; the improvement comprising the orbiting valve being non-rotatively connected to the wobble stick for rotation therewith and the second distance being different from said first distance by less than the dimension of the valving opening.

20. The improved gerotor device of Claim 19 wherein the orbiting valve has an outer circumference and characterized in that the inner valving openings are notches in the outer circumference of the orbiting valve.

21. The improved gerotor device of Claim 19 characterized in that the inner valving openings are holes in the orbiting valve.

22. The improved gerotor device of Claim 19 wherein the bidirectional passage valving openings have a diagonal length and characterized in that the inner valving openings are diagonally spaced from said outer valving openings by at least this diagonal length.

23. The improved device of Claim 19 wherein such device has gerotor cells and characterised in that such device has five or fewer gerotor cells.

24. In a gerotor hydraulic pressure device having a rotor with a separate wobble stick toe driven orbiting valve, the orbiting valve having an outer circumference and inner and outer valving openings that cooperate with bi-directional passage valving openings in the body of the device to valve the device, the improvement comprising the outer circumference of the orbiting valve having a series of notches, said series of notches being the outer valving openings, the orbiting valve having a series of holes, said series of holes being the inner valving openings and the orbiting valve being non-rotatively connected to the wobble stick for rotation therewith.

25. The improved gerotor hydraulic device of Claim 24 wherein the device has gerotor cells and characterized in that there are five gerotor cells, four notches as the outer valving openings, and four holes as the inner valving openings.

26. The improved gerotor hydraulic pressure device of Claim 24 wherein the bi-directional passage valving openings have a diagonal dimension on the surface of a valving plate of the body of the device and characterized in that each of said holes are diagonally spaced from each of said notches on the surface of the orbiting valve adjacent to the surface of the valving plate by at least such diagonal dimension of the bi-directional passage valving openings.

27. The improved gerotor hydraulic pressure device of Claim 26 wherein the gerotor device includes longitudinally extending bolts and said notches allow clearance for the bolts.

28. The improved gerotor hydraulic pressure device of Claim 24 wherein there is fluid commutation to and from the valve and characterized in that this fluid commutation to and from the valve occurs on a different side of the orbiting valve from the valving of the inner and outer valving openings to the bi-directional passage valving openings.

29. The improved gerotor hydraulic pressure device of Claim 24 wherein there are cell openings for the bi-directional passages opening into the rotor cavity and the rotor is driven by a heavy toothed wobble stick tracing a pattern on the surface of the valving plate and characterized in that the radially inside edge of the cell openings are laid out to clear the pattern traced by the heavy toothed wobble stick.

30. The improved gerotor hydraulic pressure device of Claim 29 characterized by the addition of a case drain passage for the interior of the gerotor device, said case drain passage including a hole within the pattern traced by the heavy toothed wobble stick.

31. The improved gerotor hydraulic pressure device of Claim 24 wherein there are passages leading to and from ports to commutation openings to and from.the orbiting valve and characterized in that these passages leading to and from ports to commutation openings are asymmetrically laid out.

32. The improved gerotor hydraulic pressure device of Claim 24 wherein said series of holes is interconnected by a groove on the face of the orbiting valve facing the bidirectional passage valving openings.

33. In a gerotor hydraulic pressure device having a rotor with a separate wobble stick toe driven orbiting valve, the orbiting valve having an outer circumference and inner and outer valving openings that cooperate with the bidirectional passage valving openings in the body of the device to valve the device, the outside edge of the inner valving openings extending a first distance from the centre of the valve and the inside edge of the outer valving openings extending a second distance from the centre of the valve, the improvement of the orbiting valve being nonrotatively connected to the wobble stick for rotation therewith and the second distance being less than said first distance, the outer valving openings being notches in the outer circumference of the orbiting valve, and the inner valving openings being holes in the orbiting valve.

34. The improved gerotor device of Claim 33 wherein the bidirectional passage valving openings have a diagonal length and characterized in that the notches are diagonally spaced from the holes by at least this diagonal length.

35. The improved gerotor hydraulic pressure device of claim 33 wherein there is fluid commutation to and from the valve and characterized in that this fluid commutation to and from the valve occurs on a different side of the orbiting valve from the valving of the inner and outer valving openings to the bi-directional passage valving openings.

36. The improved gerotor hydraulic pressure device of Claim 33 wherein there are cell openings for the bi-directional passages opening into the rotor cavity and the rotor is driven by a heavy toothed wobble stick tracing a pattern on the surface of the valving plate and characterized in that the radially inside edge of the cell openings are laid out to clear the pattern traced by the heavy toothed wobble stick.

37. The improved gerotor hydraulic pressure device of Claim 33 characterized by the addition of a case drain passage for the interior of the gerotor device, said case drain passage including a hole within the pattern traced by the heavy toothed wobble stick.

38. In a gerotor hydraulic pressure device having a rotor with a separate wobble stick toe driven orbiting valve, an improved connection for the orbiting valve comprising means to interconnect the orbiting valve to the wobble stick toe so as to rotatively lock the orbiting valve to the wobble stick.

39. In a gerotor hydraulic pressure device having a rotor with a separate wobble stick toe driven orbiting valve, the orbiting valve having an outer circumference that cooperates with bi-directional passage valving openings in the body of the device to partially valve the device, the improvement of notches in the outer circumference of the orbiting valve.

40. In a gerotor hydraulic pressure device having a wobble stick toe driven orbiting valve, the orbiting valve having inner and outer valving openings that cooperate with bidirectional valving openings in the body of the device to valve the device with fluid commutation to and from the valve, the improvement of the fluid commutation to and from the valve occurring on a different side of the orbiting valve from the valving to the bi-directional passage valving openings, and wherein the fluid commutation passages and bidirectional passages are each within a multiplate construction section on either side of the orbiting valve.

41. A gerotor hydraulic pressure device substantially as hereinbefore described with reference to Figures 1-17 and 19, or Figures 1-17 and 19, as modified in Figure 20 of the accompanying drawings.