WO2015085089A1

WO2015085089A1 - Wobble plate device

Info

Publication number: WO2015085089A1
Application number: PCT/US2014/068618
Authority: WO
Inventors: Kent E. LEININGER
Original assignee: Leininger Kent E
Priority date: 2013-12-07
Filing date: 2014-12-04
Publication date: 2015-06-11

Abstract

A wobble plate device comprises a frame that supports a drive shaft and a wobble plate mounted at an oblique angle to an axis of rotation of the drive shaft. Moreover, the device comprises a riding shaft suspended by the frame spaced from an end periphery of the wobble plate. An axial piston assembly is arranged to traverse along the riding shaft. The axial piston assembly comprises a C-mass section, an arm extending from the C-mass section to a position over the wobble plate, a ball extending from the arm towards the wobble plate, and a puck. The puck includes a socket that receives the ball, and a base extending from a first major surface of the wobble plate. In operation, rotational movement of the wobble plate causes corresponding linear movement of the axial piston assembly along the riding shaft.

Description

WOBBLE PLATE DEVICE

TECHNICAL FIELD

Various aspects of the present disclosure relate generally to a device with a wobble plate, and more particularly to a device that uses a wobble plate to efficiently transform between rotational motion and linear motion.

BACKGROUND ART

A wobble plate can be used to convert between rotational motion and linear motion. More particularly, a typical wobble plate device includes a surface that is tilted at an angle relative to a shaft that rotates the wobble plate such that the plane of the wobble plate surface is inclined relative to the rotational axis of the shaft. In this regard, the wobble plate can function as an axial piston motor by using pressure thrust onto a set of pistons arrayed around the tilted surface of the wobble plate to convert the linear reciprocating motion of the pistons into rotational movement of the wobble plate. Rotation of the wobble plate in turn, rotates the shaft. The wobble plate can also function as a pump. In this implementation, the shaft is caused to rotate, which correspondingly rotates the wobble plate. The wobble plate causes reciprocating motion to a set of pistons arrayed around the tilted surface of the wobble plate.

SUMMARY OF INVENTION

According to aspects of the present disclosure herein, a wobble plate device comprises a frame, a wobble plate, a translation station, and an axial piston assembly. The frame supports a drive shaft for axial rotation within the frame. The wobble plate has a first major surface and a second major surface opposite the first major surface. Moreover, the wobble plate is mounted at an oblique angle to an axis of rotation of the drive shaft such that rotational motion of the drive shaft causes corresponding rotational motion of the wobble plate.

The translation station has a riding shaft spaced from an end periphery of the wobble plate. The axial piston assembly is arranged to traverse along the riding shaft. The axial piston assembly includes a first mass section, a first arm extending from the first mass section to a position over the first major surface of the wobble plate, a second mass section, and a second arm extending from the second mass section to a position over the second major surface of the wobble plate. In operation, rotational movement of the wobble plate causes corresponding linear movement of the axial piston assembly along the riding shaft. BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is a perspective view of a wobble plate device according to aspects of the present disclosure;

FIG. 2 is a side view of an example frame member that implements a manifold for the delivery of fluid to the wobble plate device;

FIG. 3 is a cross-sectional view of a riding shaft according to an example implementation, illustrating the internal passageway that delivers fluid from the manifold to the wobble plate;

FIG. 4 is a partial cutaway view of a section of an axial piston assembly coupled to a riding shaft according to an example implementation;

FIG. 5 is a schematic view illustrating a top-down view of a portion of an axial piston assembly according to an example implementation, illustrating the symmetry of the components thereof;

FIG. 6 is a schematic view according to an example implementation, illustrating the orifices in a riding shaft that provide fluid to a reservoir are located along the shaft so that as the corresponding axial piston assembly traverses along the shaft, the piston assembly always overlies the orifices;

FIG. 7 is a side schematic cross-sectional view of an axial piston assembly according to an example implementation, illustrating the first riding shaft and the second riding shaft and the fluid path from the interior of the riding shafts to the reservoirs to the pathways that lead through the first and second arms;

FIG. 8 is a schematic view according to an example implementation, illustrating the flow of fluid through a pair of opposing hydrostatic thrust bearings according to aspects of the present disclosure;

FIG. 9 is a schematic view according to an example implementation, of a single thrust bearing;

FIG. 10 is a schematic view according to an example implementation, of the relationship between a ball, and a puck that functions as a hydrostatic thrust bearing, according to aspects of the present disclosure; FIG. 11 is a perspective view according to an example implementation, of an upper section of a hydrostatic thrust bearing according to aspects of the present disclosure;

FIG. 12 is a perspective view according to an example implementation, of a lower section of a hydrostatic thrust bearing that mates with the upper section of FIG. 11;

FIG. 13 is a bottom view of the lower section of the hydrostatic thrust bearing of

FIG 12, according to aspects of the present disclosure; and

FIG. 14 is a schematic view of a wobble plate device connected in an example system. MODES FOR CARRYING OUT THE DISCLOSURE

Various aspects of the present disclosure describe a wobble plate device that provides an efficient and effective conversion between rotational motion and linear motion. In this regard, the wobble plate device provides torque multiplication that can be used to generate electricity, to operate pistons for applications such as compressors, to convert the generated linear motion back to rotational motion, e.g., to act as a motor, to tap off of the torque multiplied output of the rotating shaft, or perform other tasks.

In certain implementations herein, a wobble plate device includes a wobble plate having a pair of parallel major surfaces. This allows the wobble plate to work in two opposing directions, such as by using a piston assembly constructed as a "C-mass" assembly that symmetrically straddles the outer circumference of the wobble plate and attaches to each major surface of the wobble plate via a bearing, e.g., a hydrostatic bearing, magnetic bearing, etc. Here, the piston assembly traverses back and forth along one or more riding shafts (also referred to herein as rails) that extend parallel to the drive shaft. In this configuration, when the wobble plate pushes a first one of the thrust bearings in a first direction, the piston assembly travels in the first direction along the length of the riding shaft(s). Likewise, the second thrust bearing is pulled in the first direction due to the structure of the C-mass assembly. Likewise, when the wobble plate pushes the second thrust bearing in the second direction, the piston assembly travels along the riding shaft(s) in the second direction. Likewise, the first thrust bearing is pulled in the second direction. As such, thrust is generated in both linear directions (double thrust). Accordingly, springs and/or other additional hardware are not required, as is typical of common compressors and other like devices. In certain implementations herein, such as generator applications, it may be sufficient that the wobble plate is fixed relative to a drive shaft so as to rotate at a fixed oblique angle. That is, the major surfaces of the wobble plate are not adjustable relative to the axis of rotation of the drive shaft that turns the wobble plate.

Moreover, multiple piston assemblies (analogous to that described above) can be arrayed around the circumference of the wobble plate. Thus, each piston assembly is configured so as to traverse linearly along one or more corresponding riding shafts that run parallel to the drive shaft that rotates the wobble plate. Because the piston assemblies ride on rails, back and forth in synchronization with the rotation of the wobble plate, the piston assemblies act as followers of the wobble plate. As such, there is no need for bores or other cylinder chambers common in piston-type compressors and other traditional swash plate structures.

General System Overview:

Referring to drawings and in particular to FIG. 1 , a wobble plate device 10 is illustrated according to various aspects of the present disclosure. In general, the wobble plate device 10 comprises a frame 12, which includes a first frame member 12A and a second frame member 12B positioned opposite the first frame member 12 A. The first frame member 12A includes a base 14A and a support member 16A extending from the base 14A. Likewise, the second frame member 12B includes a base 14B and a support member 16B extending from the base 14B. As illustrated, the first frame member 12A and the second frame member 12B are similarly dimensioned and form "bookends" of the wobble plate device 10. However, in practice, the frame 12 can take on any desired shape, e.g., a housing that covers and encloses the content of the wobble plate device 10, or other desired form factor.

The first frame member 12A has an aperture 18 through the support member 16A through which a drive shaft 20 passes. The aperture 18 may include a bearing or other suitable structure to allow the shaft 20 to rotate relative to the first frame member 12 A. Moreover, since the shaft 20 enters the frame 12 at the aperture 18 along the first support member 16A of the first frame member 12 A, this portion of the device is generally referred to as the input.

The second frame member 12B has a bearing mounted in or on the support member 16B, which receives the drive shaft 20 such that the drive shaft 20 is supported by the frame 12 and is journaled for rotation within the frame 12 between the first frame member 12A and the second frame member 12B. In yet further implementations, the drive shaft 20 may extend entirely through the second frame member 12B so as to project outside the frame 12, thus providing a torque multiplied output. In still further exemplary implementations, the drive shaft 20 need not be supported by the second frame member 12B, e.g., such as where the drive shaft 20 can cantilever into the frame 12 or where the drive shaft 20 is otherwise suitably mounted.

External to the frame 12, the drive shaft 20 may be coupled to any desired components (not shown for sake of clarity). For instance, in an application where the wobble plate device 10 converts rotational motion into linear motion, the drive shaft 20 may connect (e.g., outside of the frame 12) to a gear box, which is driven by a motor. As another example, where the wobble plate device 10 is used to convert linear motion into rotational motion, the drive shaft 20 external to the frame 12 may connect to one or more gears, belt and pulleys, or other devices.

A wobble plate 22 is mounted at an oblique angle to an axis of rotation of the drive shaft 20 such that rotational motion of the drive shaft 20 causes corresponding rotational motion of the wobble plate 22. The wobble plate has a first major surface 22A and a second major surface 22B, which is positioned opposite the first major surface 22A. Moreover, in certain implementations, the first major surface 22A is parallel to the second major surface 22B. In an example implementation, the angle of the wobble plate 22 (oblique angle of the wobble plate 22 relative to the drive shaft 20) is set (i.e., fixed) and does not change during operation of the device 10.

At least one translation station 30 is positioned within the frame 12. For instance, as illustrated, there are six translation stations 30 extending between the first frame member 12A and the second frame member 12B. The various translation stations 30 are spaced apart so as to circumscribe the wobble plate 22. Moreover, each translation station 30 defines a linear path between the first frame member 12A and the second frame member 12B. For instance, in an illustrative implementation, each translation station 30 is implemented by a pair of spaced shafts defining a first riding shaft 32 and a second riding shaft 34 that each extend between, and are supported by, the first frame member 12A and the second frame member 12B. In particular, the first riding shaft 32 runs parallel to the second riding shaft 34 between the first support member 16A of the first frame member 12A and the second support member 16B of the second frame member 12B. Moreover, the first riding shaft 32 and the second riding shaft 34 may extend parallel to the drive shaft 20. In an alternative example implementation, each translation station 30 may comprise a single riding shaft.

Although a wobble plate device 10 may function with a single translation station 30, the overall application will dictate ultimate number of translation stations 30 provided in a specific implementation. For instance, two translation stations 30 may be utilized to generate single phase power. Likewise, four translation stations 30 may be utilized to generate two phase power, and six translation stations 30 may be utilized to generate three-phase power. As another example, four translation stations 30 may be utilized to drive a four piston compressor, etc.

An axial piston assembly 40 is associated with each of the translation stations 30. More particularly, each axial piston assembly 40 is slidably mounted to a corresponding translation station 30 so as to traverse along a linear path between the first frame member 12A and the second frame member 12B. For instance, each axial piston assembly 40 may traverse along a corresponding riding shaft of an associated translation station 30.

Each axial piston assembly 40 is further coupled to both the first major surface 22A and the second major surface 22B of the wobble plate 22. For instance, the axial piston assembly can include a first mass section, a first arm extending from the first mass section to a position over the first major surface 22A of the wobble plate 22, a second mass section, and a second arm extending from the second mass section to a position over the second major surface 22B of the wobble plate 22. In this manner, an axial piston assembly traverses along the corresponding translation station 30 in response to rotation of the wobble plate 22. In certain implementations, the configuration of the axial piston assembly 40 may dictate whether to use a single riding shaft or multiple riding shafts for each translation station 30.

Axial Piston Assembly:

In an example implementation of the wobble plate device 10, an axial piston assembly 40 is constructed as a C-mass assembly that symmetrically straddles the outer circumference of the wobble plate. The axial piston assembly traverses linearly along the pair of shafts defining the first riding shaft 32 and second riding shaft 34, such as by using fluid film bushings. Moreover, the axial piston assembly 40 attaches to each major surface (i.e., the first major surface 22A and the second major surface 22B) of the wobble plate 22 via a suitable bearing, e.g., a hydrostatic thrust bearing.

More particularly, in the example implementation, each axial piston assembly 40 comprises a first end cap 42, a first mass section 44 adjacent to the first end cap 42, a block 46 adjacent to the first mass section 44, a second mass section 48 adjacent to the block 46, and a second end cap 50 adjacent to the second mass section 48. Because the overall axial piston assembly 40 takes on a generally C-shape in the example implementation, the first mass section 44 is also referred to herein as a first C-mass section 44. Likewise, the second mass section 48 is also referred to herein as a second C-mass section. In this manner, the block 46 is positioned between the first C-mass section 44 and the second C-mass section 48. The first C-mass section 44 is positioned between the first end 42 and the block 46. Likewise, the second C-mass section 48 is positioned between the block 46 and the second end 50.

Each axial piston assembly 40 also comprises a first arm 52 extending from the first C-mass section 44 to a position over and spaced from the first major surface 22A of the wobble plate 20. Analogously, each axial piston assembly 40 comprises a second arm 54 extending from the second C-mass section 48, to a position over and spaced from the second major surface 22B of the wobble plate 22.

Each of the arms 52, 54 includes a ball 56 at the distal end of the arm 52, 54 towards the wobble plate 22. A puck 58 has a socket 60 that receives the ball 56, and a base 62 adjacent to the wobble plate 22, as will be described in greater detail herein.

In this regard, each axial piston assembly 40 includes a first ball 56 extending from the first arm 52 towards the first major surface 22A of the wobble plate 22, and a first puck 58 having a socket 60 that receives the first ball 56, and a base 62 adjacent to the first major surface 22A of the wobble plate 22. Likewise, each axial piston assembly 40 includes a second ball 56 extending from the second arm 54 towards the second major surface 22B of the wobble plate 22, and a second puck 58 having a socket 60 that receives the second ball 56 and a base 62 proximate to the second major surface 22B of the wobble plate 22. In an example implementation, the pucks 58 function as hydrostatic bearings, as will be described in greater detail herein.

In operation, rotational movement of the wobble plate 22 causes corresponding linear movement of each axial piston assembly 40 in a reciprocating manner along the corresponding translation station 30. Notably, by configuring the piston assembly 40 to straddle the wobble plate 22, the wobble plate device 10 can be balanced through the design of the axial piston assembly 40 and will remain balanced during operation. That is, for each translation station 30, the corresponding piston assembly 40 includes a first arm 52, ball 56 and puck 58 on a first side of the wobble plate 22, and a corresponding second arm 54, ball 56 and puck 58 on a second side of the wobble plate opposite the first arm 52, ball 56 and puck 58.

Example Operation:

In operation, a motor (e.g., a five horse power (5 HP) motor) turns a gearbox attached to the shaft 20 outside the first frame member 12 A. A motor with a different horse power rating may alternatively be used. As an illustrative example, a gearbox may be direct drive or shaft mounted to a C-face motor to produce 600 revolutions per minute (RPM) output at 540 inch pounds of torque. As another example, for generating electricity, the gearbox may output 60 RPM.

Regardless of speed, as the shaft rotates, the wobble plate 22 also rotates. Because of the oblique angle of the wobble plate 22 relative to the shaft 20, an edge of the wobble plate 22 describes a path that oscillates along the shaft's length as observed from a non- rotating point of view away from the shaft. The apparent linear motion is converted into actual linear motion because the pucks 58 function as followers that do not turn with the wobble plate 22. Rather, each puck 58 presses against one of the disk's two surfaces (first major surface 22A or second major surface 22B) near the circumference of the wobble plate 22.

In this configuration, when the wobble plate 22 pushes the puck 58 attached to the first arm 52 in a first direction, the axial piston assembly 40 travels in the first direction along the length of the first riding shaft 32 and the second riding shaft 34. Likewise, the second puck 58 attached to the second arm 54 is pulled in the first direction due to the structure of the C-mass assembly. Likewise, when the wobble plate 22 pushes the second puck 58 in a second direction opposite the first direction the axial piston assembly 40 travels along the first riding shaft 32 and the second riding shaft 34 in the second direction. Likewise, the first puck 58 is pulled in the second direction. As such, thrust is generated in both linear directions (double thrust).

Keeping with the above examples, the wobble plate 22 may have a 16" (approximately 40.64 centimeters) centerline diameter. In an example implementation, a 1" thick wobble plate 22 is mounted at a 30 degree angle relative to a perpendicular plane to the axial length of the drive shaft 20. In this example, the wobble plate 22 has an actual diameter of approximately 18.48" (approximately 46.93 centimeters).

In an example implementation, the axial piston assemblies 40 are implemented as C-style assemblies that encapsulate both sides of the wobble plate 22 via the pucks 58 (e.g., hydrostatic thrust bearings). Moreover, bushings serve as bearing points to enable the axial piston assembly 40 to traverse the associated translation station 30, using fluid film/hydrostatic technology or other frictionless bearing technology, e.g., magnetic support components.

The frame 12 may be mounted in a horizontal fashion to the frame 12 via frictionless bushings to support the mass of the drive shaft 20, with the wobble plate 22 installed thereon. When in motion, a balanced operation should be noticed, somewhat like a gyro due to the symmetry of the axial piston assemblies 40. However, if the frame 12 is mounted vertically, a frictionless thrust bearing may be necessary on the bottom of the main drive shaft with a frictionless bushing below the gearbox for maintaining balanced rotation.

As the external motor (not shown in FIG. 1) drives the gearbox (also not shown in FIG. 1), the resultant torque is transferred into the drive shaft 20, which rotates the wobble plate 22. The wobble plate 22 accelerates the mass of the axial piston assemblies 40, e.g., to a force calculated to be a minimum of 30 times greater than the mass of the axial piston assemblies in an example implementation. An average accelerated force of the combined axial piston assemblies (e.g., using four axial piston assemblies) can create an output greater than the input, e.g., approximately 18 times greater than a five horse power (5 HP) input used to rotate the drive shaft 20 in the above example.

The force generated by the wobble plate device 10 may be applied, such as through use of timing belts attached to the axial piston assemblies 40 using a cam arrangement in an offset fashion on the axial piston assemblies, to drive a timing belt pulley on an external shaft, such as through a roller/ramp clutch. The reciprocating action of the axial piston assemblies 40 occurs each time a complete revolution of the wobble plate 22 occurs and the output is one complete revolution of the drive shaft 20. The total up/down stroke is related to the pitch diameter of the pulleys so one up/down action is one complete revolution. Alternatively, the linear motion of the axial piston assemblies 40 can be used directly. For instance, since the output is torque multiplied from the input, the drive shaft 20 can extend outside the frame 12, e.g., by extending outside the second frame member 12B. In this manner, a drive gear pulley or other device can attach directly to the drive shaft 20. As yet another example, the wobble plate device 10 can turn a jack shaft can also drive a pump so that hydraulic components can be used for power transmission of vehicles and equipment which need controlled speed.

Fluid Delivery System:

According to aspects of the present disclosure, hydraulic fluid, e.g., oil, is delivered to various components of the wobble plate device 10 to reduce friction and to enable efficient operation.

Fluid Delivery Through a Manifold and Piping:

Referring to FIG. 2, oil is delivered to the wobble plate device 10 via a manifold. For instance, as illustrated, the manifold is integrated into the first frame member 12 A. In alternative configurations, the manifold may be implemented in other structures. In general, the manifold includes a fluid delivery component 70 for each translation station 30.

Keeping with the example of FIG. 1, there are six translation stations in the exemplary wobble plate device 10. As such, there are six fluid delivery components 70. Each fluid delivery component 70 is aligned with a corresponding one of the translation stations 30. Moreover, in the example of FIG. 1, each translation station 30 comprises a first riding shaft 32 and a second riding shaft 34. As such, each fluid delivery component includes a first delivery port 72 aligned to deliver fluid to the first riding shaft 32, and a second delivery port 74 aligned to deliver fluid to the second riding shaft 34.

A pump used to deliver the fluid to the manifold is not illustrated for sake of clarity of example, but may be any pump or other device capable of supplying a constant fluid pressure. In an illustrative example, the fluid pressure is 1,600 pounds per square inch (psi), although other pressures may be used depending upon the specific application. Moreover, in an illustrative example, the fluid delivery system pumps at least 0.08 gallons per minute of fluid through each puck 58.

The first riding shaft 32 and the second riding shaft 34 each have a hollow defining a fluid passageway, e.g., through the center of the shaft. Thus, the first riding shaft 32 and the second riding shaft 34 are hollow tubes or pipes. In particular, fluid enters the manifold via the first port 72, and flows from the first port 72 into the fluid passageway within the interior of the first riding shaft 32. Likewise, fluid enters the manifold via the second port 74, and flows from the second port 74 into the fluid passageway within the interior of the second riding shaft 34.

Referring to FIG. 3, the first riding shaft 32 and the second riding shaft 34 each include a "shaft within a shaft" design. More particularly, a "notched" inner shaft 76 includes a plurality of channels or grooves that extend along the outside surface. The riding shafts 32, 34 each include a hollow therein defining a passageway 78. The notched shaft 76 is concentric and located within the passageway 78.

With reference to FIGS. 2 and 3, when the first riding shaft 32 is installed in the frame 12, the passageway 78 of the first riding shaft 32 aligns with a corresponding orifice 72 of the manifold. As such, fluid, e.g., oil, entering the manifold, e.g., from a fluid pump, passes through each instance of the orifice 72 and into the passageway 78 of each associated instance of the first riding shaft 32. This allows the fluid to fill the passageway 78 between the interior surface of the first riding shaft 32 and the outside surface of the notched shaft 76 therein. Likewise, the passageway 78 of the second riding shaft 34 aligns with a corresponding orifice 74 of the manifold. In an analogous manner, fluid, e.g., oil, entering the manifold, e.g., from a fluid pump, passes through each instance of the orifice 74 and into the passageway 78 of each associated instance of the second riding shaft 34. This allows the fluid to fill the passageway 78 between the interior surface of the second riding shaft 34 and the outside surface of the notched shaft 76 therein.

Fluid Delivery Through the Axial Piston Assembly:

The first riding shaft 32 and the second riding shaft 34 each have one or more orifices that connect the fluid passageway through the interior of the shaft to the exterior of the shaft. This allows the creation of at least one reservoir to retain and store fluid.

Moreover, this allows the creation of a hydrostatic bearing to reduce friction and to lubricate the shafts 32, 34 as the associated piston assembly 40 traverses back and forth. For instance, there may be from three to six orifices around the perimeter of the shaft. In an illustrative implementation, the orifices are not aligned in the same plane, i.e., cross- section taken perpendicular to the axial direction. Rather, the orifices may be staggered along the axial length of the shaft. Each orifice opens to the surface of the shaft so that fluid may be delivered to a reservoir in the corresponding axial piston assembly 40, as described in greater detail herein. In practice, any number of suitable orifices may be provided.

Thus, the first riding shaft 32 has a series of orifices around the perimeter of its shaft to deliver fluid from the passageway, which runs through an inner coaxial conduit of the first riding shaft, into the axial piston assembly. Likewise, the second riding shaft has a series of orifices around the perimeter of its shaft to deliver fluid from the passageway, which runs through an inner coaxial conduit of the second riding shaft, into the associated axial piston assembly 40. Working Example

Referring to FIG. 4, a cutout shows the left-hand side of a portion of an axial piston assembly 40 in cooperation with the first riding shaft 32. Only a partial view is provided for clarity of discussion herein. The discussion below applies by analogy to the structure of the axial piston assembly 40 relative to the second riding shaft 34.

As illustrated, the axial piston assembly 40 includes an end cap 42 adjacent to a first C-mass section 44. The first end cap 42 includes a retainer cap 80 that concentrically secures to a bushing 82. The retainer cap 80 secures, e.g., screws, bolts or otherwise connects to the first C-mass section 44 to facilitate easy assembly and manufacture. A plug 84 plugs the first riding shaft 32 to prevent fluid from escaping the hollow in the first riding shaft 32.

The C-mass 44 includes a hollow through which the first riding shaft 32 passes. The hollow includes an area defining a reservoir 86. Fluid in the passageway of the first riding shaft 32 fills the reservoir 86 via orifices 88 that connect the fluid passageway through the interior of the first riding shaft 32 to the exterior of the first riding shaft 32. This allows the fluid injected into the manifold to fill the reservoir 86. For instance, there may be from three to six orifices around the perimeter of the first riding shaft 32. The orifices 88 are not aligned in the same plane, i.e., cross-section taken perpendicular to the axial direction of the first riding shaft 32. Rather, the orifices 88 are staggered along the axial length of the first riding shaft 32.

A passageway 90 connects the reservoir 86 to a gap between the bushing 82 and the first riding shaft 32 to create a hydrostatic bearing 92 to reduce friction as the associated piston assembly 40 traverses back and forth. For instance, a small gap, e.g., 0.001 inches (0.0254 millimeters) extends between the surface of the first riding shaft 32 and the bushing 82. The fluid that fills the gap, e.g., an oil film keeps the axial piston assembly 40 concentric on the first riding shaft 32.

In practice, the structure of FIG. 4 is mirrored on the right-hand side of the axial piston assembly 40 in cooperation with the first riding shaft 32. Moreover, the structure of FIG. 3 is analogous to the portion of the axial piston assembly 40 in cooperation with the second riding shaft 34. As such, a first reservoir 86 is formed in an interior volume of the piston assembly 40, which receives fluid from the series of orifices 88 in the first riding shaft 32. Likewise, a second reservoir 86 is formed in an interior volume of the piston assembly 40, which receives fluid from the series of orifices 88 in the second riding shaft 34.

The first end block 42 comprises a bushing and a hydrostatic bearing 92 about each of the first riding shaft 32 and the second riding shaft 34. Likewise, the second end block 50 comprises a bushing and a hydrostatic bearing 92 about each of the first riding shaft 32 and the second riding shaft 34. Moreover, the axial piston assembly 40 is supported on each of the first riding shaft 32 and second riding shaft 34 via the bushing and corresponding hydrostatic bearing in the first end cap 42 and end cap 50.

Referring to FIG. 5, a schematic partial view of an axial piston assembly 40 illustrates that the axial piston assembly 40 rides on the first and second riding shafts 32, 34 via the bearings 92 in the first end cap 42 and second end cap 50. The view of FIG. 5 further illustrates the reservoir 86 extending between the first end cap 42 and the second end cap 50. However, the reservoir 86 may be other dimensions. Also, in practice, there is a reservoir 86 for each of the first riding shaft 32 and the second riding shaft 34. The view of FIG. 5 also illustrates the mirror image configuration of the first arm 52 and second arm 54.

Referring to FIG. 6, as noted in greater detail herein, the first riding shaft 32 and the second riding shaft 34 each include orifices 88 that allow fluid to flow into reservoirs 86 within the associated axial piston assembly 40. The axial piston assembly 40 traverses back and forth along each of the first riding shaft 32 and the second riding shaft 34. As such, the orifices 88 are located in an area where there is always some overlap of the axial piston assembly 40 regardless of where the axial piston assembly 40 is in the forward or reverse stroke.

Referring to FIG. 7, a side cross-sectional view illustrates an example where the first riding shaft 32 has six orifices 88 there along that feed a first reservoir 86. Similarly, the second riding shaft 34 includes six orifices 88 that feed the second reservoir 86. The reservoirs 86 supply a common passageway 114 to each of the arms 52, 54.

Fluid Delivery Through the Hydrostatic Thrust Bearings:

Referring to FIG. 8, a simplified schematic view illustrates the general flow of fluid from the first riding shaft 32 and second riding shaft 34 into the arms 52, 54, through the balls 56 A, 56B and through the corresponding pucks 58 A, 58B of a representative one of the piston assemblies 40.

Initially, it is noted that the shaft 20 is supported by the frame 12 via a first bearing 102, e.g., a radial hydrostatic bearing. Likewise, the shaft is supported by the frame via a second bearing 104, e.g., another radial hydrostatic bearing. The radial hydrostatic bearing 102 is provided in the aperture 18 of the support member 16A of the first frame member 12A (described with reference to FIG. 1), and the radial hydrostatic bearing 104 is supported by the support member 16B of the second frame member 16B. The wobble plate 22 mounts to the drive shaft 20 via a mounting hub 106 that fixes the angle of incline of the wobble plate (e.g., 30 degrees in a working example), and ensures that the wobble plate 22 rotates with corresponding rotation of the shaft 20.

As noted above, fluid is delivered to the piston assembly 40 via fluid passed through the first riding shaft 32 and the second riding shaft 34 from the manifold. In an illustrative implementation, the first arm 52 includes a fluid passageway to deliver fiuid from the first riding shaft 32 to the first ball 56A. The first ball 56A delivers the fluid to the corresponding first puck 58 A. Likewise, the second arm 54 includes a fluid passageway to deliver fluid from the second riding shaft 34 to the second ball 56B. The second ball 56 correspondingly delivers the fluid to the corresponding second puck 58B.

More particularly, a hydrostatic bearing is formed between the first ball 56A and socket 60 A of the first puck 58A via fluid delivered through the first ball 56A to the socket 60A of the first puck 58 A. Also, fluid is delivered through the first puck 58A to the bottom of the base 62 A of the first puck 58 A, so as to form a film of fluid between the bottom of the base 62A of the first puck 58A and the first major surface 22A of the wobble plate 22. Thus, the first puck 58A is physically separated from the first major surface 22A of the wobble plate 22 by the film of fluid defining a first hydrostatic thrust bearing. As will be described in greater detail herein, the bottom of the base 62A of the first puck 58 has at least one pocket to collect fluid. Likewise, a hydrostatic bearing is formed between the second ball 56B and socket 60B of the second puck 58B via fluid delivered through the second ball 56B to the socket 60B of the second puck 58B. Also, fluid is delivered through the second puck 58B to the a bottom of the base 62B of the second puck 58B, so as to form a film of fluid between the bottom of the base 62B of the second puck 58B and the second major surface 22B of the wobble plate 22. Accordingly, the second puck 58B is likewise physically separated from the second major surface 22B of the wobble plate 22 by the film of fluid defining a second hydrostatic thrust bearing. As will be described in greater detail herein, the bottom of the base 62B of the second puck 58B also has at least one pocket to collect fluid.

Referring to FIG. 9, as noted in greater detail herein, the first and second riding shafts 32, 34 each include orifices that connect the fluid passing through the shafts to the corresponding axial piston assembly 40. For instance, as illustrated, the first riding shaft 32 includes an orifice 88 that connects the outside surface of the first riding shaft 32 to the internal passageway through which fluid passes. This allows the formation of a fluid passageway in the region 112 in a gap between the riding shaft 32 and the axial piston assembly 40. When fluid flows through the device, the fluid in the region 112 lubricates the surface of the first riding shaft 32 and reduces friction in the linear movement of the axial piston assembly 40. As discussed in greater detail herein, the axial piston assembly 40 rides back and forth on the first riding shaft 32 and the second riding shaft 34 via the hydrostatic bushings 92 (see FIG. 4).

Fluid then flows through a passageway 114 through the first arm 52 into the ball 56 as described more fully herein. The fluid exits the ball into the socket 60 to form a hydrostatic bearing in the ball/socket region 116 that reduces friction between the ball 56 and the puck 58. The fluid further passes from the ball through a passageway 118 in the puck 58 to the bottom of the base 62.

The fluid forms hydrostatic bearing between the bottom of the base 62 of the puck 58 and the wobble plate 22 (not shown in FIG. 9 for clarity) by filling a thrust region 120 with fluid. More particularly, the base 62 of each puck 58 comprises at least one pocket 122 that recesses into the base 62 forming a gap between the base 62 and the wobble plate 22. The bottom of the base 62 further comprises at least one step 124 that is shallower than each pocket 122 so as to create a step in the gap between the base 62 of the puck 58 and the wobble plate 22. Referring to FIG. 10, a partial cross-sectional view of the wobble plate 22, ball 56, and puck 58 illustrates the formation of several hydrostatic bearings during operation. More particularly, as fluid flows, a hydrostatic bearing is formed in the ball/socket region 116 between the ball 56 and the socket 60 of the puck 58 thus reducing friction between the ball 56 and puck 58. Also, a hydrostatic bearing is formed between the base 62 and the wobble plate 22. Because of the pockets 122 and steps 124 on the bottom on the base 62, fluid forms in multiple thicknesses. As such, the film formed between the puck 58 and the wobble plate 22 is not uniform. This non-uniformity prevents friction as a result of physical contact between the puck 58 and the wobble plate 22 during operation of the device.

With reference to the preceding FIGURES, although the specification mentions a passageway, channel, orifice, orifice, pocket, step, etc., in practice, there may be multiple implementations of each of the above features, e.g., to direct fluid to different parts of the device. As such, a practical implementation is not limited to a single instance of the fluid routing features described herein.

Example Hydrostatic Thrust Bearing:

Large pressure loads can develop in the wobble plate device 10, which may lead to mechanical deformations that the hydrostatic bearing must accommodate. Moreover, the interface between the puck 58 and the wobble plate 22 is a complex interaction. For instance, the motion of the puck 58 over the wobble plate 22 changes direction and speed constantly, which makes for time changing thermal effects in the fluid forming the thrust bearing between the puck 58 and the wobble plate 22.

Referring to FIGS. 11-13, the example implementation of a puck 58 is assembled in two components including an upper component 130 (FIG. 11) and a lower component (FIGS. 12, 13). This two-component approach allows the ball 56 and puck 58 to be easily assembled during manufacturing.

Referring specifically to FIG. 11, the upper section 130 of the puck 58 includes threaded through holes that allow the upper component 130 to bolt to the lower component. The upper component 130 also comprises passageways 134 to deliver fluid to the lower component, and channels 136 to create gaps to form the hydrostatic bearing between the ball 56 and socket 60. As illustrated, the upper component 130, in practice, provides multiple passageways 134 and multiple channels 136.

Referring to FIG. 12, a view illustrates the top of the lower component 140. The lower component 140 includes threaded holes that align with the threaded through holes 132 of the upper component 130. The lower component also includes passageways 144 to facilitate fluid flow and channels 146, which are analogous to the channels 136 of FIG. 11. The lower component also includes passageways 148, which allow fluid to flow to the bottom of the puck 58. As illustrated, the lower component 140, in practice, provides multiple passageways 144, multiple passageways channels 146, and multiple passageways 148.

Referring to FIG. 13, a view illustrates the bottom of the puck 58. In particular, the bottom of the base 62 includes multiple pockets 152. The pockets are analogous to the pockets 122 of FIG. 9. Extending adjacent to each pocket 152 is a step 154 (analogous to the steps 124 of FIG. 9). As illustrated, there are in practice, multiple distinct steps 154 arranged around the periphery of the corresponding pocket 152. The base 62 of the puck 58 also includes orifices 156 that couple to at least one passageway delivering fluid into each pocket 152 (e.g., to the passageways 148 illustrated in FIG. 12).

With reference to FIGS. 11-13 generally, according to various aspects of the present disclosure, the upper component 130 defines a ring that mounts to the top of the puck via the lower component 140. Moreover, a bearing geometry is provided via the puck 58 described with reference to FIGS. 11-13, which strongly reduces the effects of thermal distortions brought about by uneven sliding film thicknesses. In particular, the geometry of the thrust bearing brings about a film thickness that facilitates a self aligning feature that prevents edge wear and misalignment, and minimizes thermal distortions. Moreover, the geometry herein can prevent or otherwise minimize fluid shearing. Fluid shearing can be detrimental to performance by generating heat and thermal distortion.

As such, the geometry herein balances fluid flow and film thicknesses in a manner that minimizes the effects of misalignment of the hydrostatic bearing to the wobble plate. As a result, the deflections are extremely small, e.g., much smaller than the film thicknesses. In this regard, the pressure forces applied to the bearing affect the deflections and stresses, which can be used to determine the pocket 142 and step 154 configuration.

As illustrated in FIG. 13, in addition to each pocket 152, one or more steps 154 are provided around the outer circumference of each pocket 152. Particularly, the bottom of the base of the puck 58 has multiple wedge shaped pockets 152, each pocket 152 in communication with at least one fluid passageway 148 extending through the puck 58.

At least one step 154 is located between a select one of the shaped pockets and an edge of the base, creating at least three different depths of fluid between the bottom of the base of the puck and the wobble plate. Moreover, the steps 154 automatically cause the leakage flow to accelerate through the sudden gap height reduction causing a large pressure increase. The arrangement is self regulating with large gaps producing less pressure increase and small gaps producing large pressure increase. The net effect is to inherently self align the bearing with respect to the rotating wobble plate 22. In the aligned state, the thermal distortions should also be minimized.

The socket 60 of each puck 58 defines a generally spherical impression for receiving the ball 56. A series of fluid passageways 134, 144, 148 extend from within the generally spherical impression through to the bottom of the base 62 (exiting out orifices 156).

In general, the thrust bearing may deform, e.g., due to thermal expansion.

Moreover, inertial impulse loads can affect the puck 58. Still further, manufacturing tolerances and other production limitations must be taken into account. As such, if the film thickness is not correctly established, the bearing may wear and ultimately fail. However, the design of the puck 58 set out herein avoids such issues.

Connecting to External Devices:

Referring to FIG. 14, a schematic representation of the wobble plate device 10 is illustrated in an exemplary system. In particular, a motor 202 is connected to a gearbox 204, which turns the shaft 20 that feeds the wobble plate device 10. A fluid delivery system 208 feeds the fluid, e.g., oil, as described more fully herein, into a manifold of the wobble plate device 10. As illustrated, the fluid delivery is to the same side of the wobble plate device 10 as the motor 202. This eliminates obstacles clutter from the output end of the wobble plate device 10, and is not a requirement. The wobble plate device 10 functions as a torque multiplier to drive an output device 210. Examples of a suitable output device 210 are set out more fully herein.

As an example application of generating electricity, the motor 202 and gearbox 204 cooperate to rotate the drive shaft 20 at 60 R.P.M. Each axial piston assembly of the wobble plate device 10 includes a conductor and magnet assembly mounted to the device so as to cooperate in conjunction with movement of the axial piston assembly so as to induce a current in the coil sufficient to generate electricity. The conductor can be a coil, plate, or other structure that will create opposing fields in cooperation with the magnets as the axial piston assembly 40 reciprocates. For instance, one or more magnets can move with the axial piston assembly with the conductor(s) remaining stationary. Alternatively, one or more conductors can move with the axial piston assembly relative to the magnets, which may be fixed in position.

Miscellaneous:

Referring to the FIGURES generally, in an illustrative implementation, instead of terminating the shaft 20 in a bearing journaled for rotation within or on the second frame 12B, the shaft could extend through the frame 12 so as to extend outside the second frame member 12. Here, the output end of the drive shaft 20 (opposite end of the drive motor), through the action of the C-mass on the wobble plate 22, can increase the output torque on the shaft 20, which could facilitate coupling the shaft 20 to another device such as a rotational generator set to produce electricity or drive other mechanical equipment.

The rectilinear motion generated by the wobble plate device 10 can be further converted to rotational motion without use of cranks, to more efficiently use the created force as torque to drive a final output shaft (not shown). For instance, the output of the wobble plate device 10 can be used to drive timing belts that are not subject to stretch but utilizing material like carbon fiber or Kevlar in the core. As an example, an embodiment may use four axial piston assemblies. In this implementation, two belt assemblies (using two belts per assembly) can be mounted at 180 degrees around the wobble plate relative to each other, to drive one common shaft between these a first pair of the axial piston assemblies, while two other belt assemblies connected to the other pair of axial piston assemblies. Each drive a shaft set parallel to the first long shaft. Use of roller ramp clutches on the pulleys, drive one belt while the other recovers during each up/down action of the belt assemblies.

If imbalance/vibration is discovered when only driving one pulley per belt, splitting the increased load to a drive shaft on each end of the belt assemblies should be done to balance the system and minimize vibration. Timing belts may be utilized to connect two parallel shafts to one common shaft and this common shaft to a jackshaft to drive another piece of equipment such as a generator (AC or DC), hydraulic drive, or transmission to be used in motion of a vehicle.

Although described with reference to hydrostatic bearings, other bearings may be utilized including air, magnetic, etc.

The torque multiplication of the wobble plate device 10 is constant. However, a need for varying speed to other equipment can be accomplished by other devices external to the wobble plate device 10.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as orifice, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. Aspects of the disclosure were chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.

Claims

What is claimed is: 1. A device comprising:

a frame that supports a drive shaft for axial rotation within the frame;

a wobble plate mounted at an oblique angle to an axis of rotation of the drive shaft such that rotational motion of the drive shaft causes corresponding rotational motion of the wobble plate, wherein the wobble plate has a first major surface and a second major surface opposite the first major surface;

a translation station having a riding shaft spaced from an end periphery of the wobble plate; and

an axial piston assembly arranged to traverse along the riding shaft, comprising: a first mass section;

a first arm extending from the first mass section to a position over the first major surface of the wobble plate;

a second mass section; and

a second arm extending from the second mass section to a position over the second major surface of the wobble plate;

wherein:

rotational movement of the wobble plate causes corresponding linear movement of the axial piston assembly along the riding shaft.

2. The device of claim 1, wherein:

the riding shaft defines a first riding shaft;

the translation station further comprising:

a second riding shaft spaced apart and parallel to the first riding shaft such that the axial piston assembly is coupled to both the first riding shaft and the second riding shaft.

3. The device of claim 2, wherein:

the axial piston assembly further comprises:

a first ball extending from the first arm towards the wobble plate;

a first puck having a socket that receives the first ball, and a base extending from the first major surface of the wobble plate;

a second ball extending from the second arm towards the wobble plate; and a second puck having a socket that receives the second ball, and a base extending from the second major surface of the wobble plate generally opposite the first puck.

4. The device of claim 3, wherein:

the axial piston assembly further comprises:

a first end cap;

a second end cap; and

a fluid delivery system that delivers fluid to the device;

wherein:

the first end cap and second end cap bookend the first mass section and the second mass section;

the first end cap and second end cap each receive fluid from the fluid delivery system so as to form a first hydrostatic bushing that supports the axial piston assembly on the first riding shaft, and so as to form a second hydrostatic bushing that supports the axial piston assembly on the second riding shaft;

the first end cap and second end cap each receive fluid from the fluid delivery system so as to form a first hydrostatic bearing with respect to the first riding shaft and a second hydrostatic bearing with respect to the second riding shaft, thus facilitating the ability of the axial piston assembly to reciprocate along the first riding shaft and the second riding shaft;

the first puck is physically separated from the first major surface of the wobble plate by a film of fluid, defining a first hydrostatic thrust bearing; and

the second puck is physically separated from the second major surface of the wobble plate by a film of fluid defining a second hydrostatic thrust bearing.

5. The device of claim 1, wherein:

the frame comprises a first frame member and a second frame member opposite the first frame member, wherein:

the first frame member has an aperture for receiving the drive shaft therethrough; and

at least one of the first frame member and the second frame member defines a manifold that includes a fluid passageway to deliver f uid from a fluid delivery system to the riding shaft.

6. The device of claim 5, wherein:

the riding shaft defines a first riding shaft having a fluid passageway defined by a hollow in the first riding shaft, to receive a flow of fluid from the manifold;

the translation station further comprising:

a second riding shaft spaced apart and parallel to the first riding shaft such that the axial piston assembly is coupled to both the first riding shaft and the second riding shaft, the second riding shaft having a fluid passageway to receive a flow of fluid from the manifold.

7. The device according to claim 6, wherein:

the fluid passageway of the first riding extends axially through the first riding shaft;

the first riding shaft has:

a notched shaft that extends concentrically within the passageway; and

at least one orifice that extends in a radial direction from a surface of the first riding shaft into the fluid passageway to deliver fluid passing within the fluid passageway between the notched shaft and the interior surface of the first riding shaft, into the axial piston assembly; the fluid passageway of the second riding shaft extends axially through the second riding shaft; and the second riding shaft has:

a notched shaft that extends concentrically within the passageway; and

at least one orifice that extends in a radial direction from a surface of the second riding shaft into the fiuid passageway, to deliver fluid passing within the fluid passageway between the notched shaft and the interior surface of the second riding shaft, into the axial piston assembly.

8. The device according to claim 7, wherein:

a first reservoir is formed in an interior volume of the axial piston assembly, the first reservoir receiving fluid that flows from the at least one orifice in the first riding shaft;

a second reservoir is formed in an interior volume of the piston assembly, the second reservoir receiving fluid from the at least one orifice in the second riding shaft; the first end block comprises a bushing and a hydrostatic bearing about each of the first riding shaft and the second riding shaft; and

the second end block comprises a bushing and a hydrostatic bearing about each of the first riding shaft and the second riding shaft;

wherein:

the hydrostatic bearings of the first end block and the second end block keep the axial piston assembly concentric with the first and second riding shafts.

9. The device according to claim 8, wherein:

the axial piston assembly further comprises:

a first ball extending from the first arm towards the wobble plate;

a second ball extending from the second arm towards the wobble plate; a second puck having a socket that receives the second ball, and a base extending from the second major surface of the wobble plate generally opposite the first puck;

the first arm includes a fluid passageway to deliver f uid from at least one of the first reservoir or the second reservoir, to the first ball, wherein the first ball delivers the fluid to the corresponding first puck; and

the second arm includes a fluid passageway to deliver fluid from at least one of the first reservoir or the second reservoir, to the second ball, wherein the second ball delivers the fluid to the corresponding second puck.

10. The device according to claim 9, wherein:

the first puck includes a fluid passageway to deliver fluid to a bottom of the base of the first puck, so as to form a film of fluid between the bottom of the base of the first puck and the first major surface of the wobble plate, the bottom of the base of the first puck having at least one pocket to collect fluid; and

the second puck includes a fluid passageway to deliver fluid to a bottom of the base of the second puck, so as to form a film of fluid between the bottom of the base of the second puck and the second major surface of the wobble plate, the bottom of the base of the second puck having at least one pocket to collect fluid.

11. The device of claim 1 , wherein:

the base of the first puck comprises at least one pocket that recesses into the base forming a gap between the base and the first major surface of the wobble plate; and

the base of the second puck comprises at least one pocket that recesses into the base forming a gap between the base and the second major surface of the wobble plate.

12. The device of claim 11, wherein the bottom of the base further comprises at least one step that is more shallow than each pocket so as to create a step in the gap between the base of the puck and the wobble plate.

13. The device of claim 1 , wherein:

the axial piston assembly further comprises:

a first ball extending from the first arm towards the wobble plate;

a second ball extending from the second arm towards the wobble plate; and a second puck having a socket that receives the second ball, and a base extending from the second major surface of the wobble plate generally opposite the first puck;

further comprising:

a fluid passageway through the axial piston assembly;

a fluid passageway through the first ball and first puck to form a film of fluid between the base of the first puck and the first major surface of the wobble plate; and

a fluid passageway through the second ball and second puck to form a film of fluid between the base of the second puck and the second major surface of the wobble plate.

14. The device of claim 13 further comprising:

a fluid delivery system that pumps at least 0.08 gallons per minute of fluid through each puck.

15. The device of claim 14, further comprising a fluid pressure source that injects the fluid through the device with a pressure of at least 1600 pounds per square inch.

16. The device of claim 1, further comprising a conductor and magnet assembly mounted to the device so as to cooperate in conjunction with movement of the axial piston assembly so as to induce a current in the coil sufficient to generate electricity.

17. A device comprising:

a frame having a first frame member and a second frame member opposite the first frame member, wherein:

the first frame member has an orifice for receiving a drive shaft

therethrough; and

the second frame member has a bearing for receiving the drive shaft such that the drive shaft is supported by the frame and is journaled for rotation within the frame;

a wobble plate mounted at an oblique angle to an axis of rotation of the drive shaft such that rotational motion of the drive shaft causes corresponding rotational motion of the wobble plate, wherein the wobble plate has a first major surface and a second major surface opposite and parallel to the first major surface; at least four translation stations extending between the first frame member and the second frame member, which are spaced apart so as to circumscribe the wobble plate and define a linear path between the first frame member and the second frame member; and an axial piston assembly associated with each one of the at least four translation stations, each axial piston assembly arranged to traverse along the linear path between the first frame member and the second frame member, each axial piston assembly comprising:

a first C-mass section;

a first arm extending from the first C-mass section, to a position over and spaced from the first major surface of the wobble plate;

a first ball extending from the first arm towards the wobble plate;

a first puck having a base extending from the first major surface of the wobble plate and a socket that receives the first ball;

a second C-mass section;

a second arm extending from the second C-mass section, to a position over and spaced from the second major surface of the wobble plate;

a second ball extending from the second arm towards the wobble plate; and a second puck having a base extending from the second major surface of the wobble plate and a socket that receives the second ball generally opposite the first puck;

wherein:

rotational movement of the wobble plate causes corresponding linear movement of each axial piston assembly.

18. The device according to claim 17, wherein:

each translation station comprises:

a pair of spaced shafts defining a first riding shaft and a second riding shaft that extend between the first frame member and the second frame member, the first riding shaft having a hollowed out portion to deliver fluid received from a fluid delivery system to the first C-mass section, and the second riding shaft having a hollowed out portion to deliver fluid received from the fluid delivery system to the second C-mass section.

19. The device according to claim 18, wherein:

a first reservoir is formed in an interior volume of the axial piston assembly, the first reservoir receiving fluid from the series of orifices in the first riding shaft;

a second reservoir is formed in an interior volume of the piston assembly, the second reservoir receiving fluid from the series of orifices in the second riding shaft; the axial piston assembly further comprises a first end block having a bushing and a hydrostatic bearing about each of the first riding shaft and the second riding shaft; and the axial piston assembly further comprises a second end block having a bushing and a hydrostatic bearing about each of the first riding shaft and the second riding shaft; wherein:

20. The device according to claim 19, wherein:

the first arm of each axial piston assembly includes a fluid passageway to deliver fluid from the first riding shaft to the first ball, wherein the first ball delivers the fluid to the corresponding first puck; and

the second arm of each axial piston assembly includes a fluid passageway to deliver fluid from the second riding shaft to the second ball, wherein the second ball delivers the fluid to the corresponding second puck.

21. The device according to claim 20, wherein:

the first puck of each axial piston assembly includes a fluid passageway to deliver fluid to a bottom of the base of the first puck, so as to form a film of fluid between the bottom of the base of the first puck and the first major surface of the wobble plate, the bottom of the base of the first puck having at least one pocket to collect fluid and at least one step that is more shallow than each pocket so as to create a step in the gap between the base of the first puck and the wobble plate; and

the second puck of each axial piston assembly includes a fluid passageway to deliver fluid to a bottom of the base of the second puck, so as to form a film of fluid between the bottom of the base of the second puck and the second major surface of the wobble plate, the bottom of the base of the second puck having at least one pocket to collect fluid and at least one step that is more shallow than each pocket so as to create a step in the gap between the base of the second puck and the wobble plate.