RETAINER DRIVE PLATE WITH INTEGRATED TORQUE AND RETENTION COMPONENTS FOR USE WITH A BENT-AXIS HYDRAULIC PUMP/MOTOR

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Patent Application Serial No. 63/062,096, filed on August 6, 2020, the disclosure of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

This disclosure relates to an axial piston hydraulic device of the bent-axis type.

BACKGROUND

An axial piston pump or motor of the “bent axis” type is one in which the axis of the input-output shaft is coaxial with the axis of rotation of the cylinder barrel only when the device is in its zero displacement condition. The greater the angle of displacement of the rotating group, the larger the output flow per revolution of the inputoutput shaft, when the device is being used as a pump or motor.

The design of the bent axis pump or motor includes a retainer plate and barrel drive features that are typically managed separately. As such, the design can require more parts and require high tolerance machining of barrel features inside the barrel drive.

Further improvements are desirable to reduce the complexity of design and manufacture.

SUMMARY

The present disclosure is directed to simplifying the design of a bent-axis hydraulic pump/motor. The design has a multi-functional hub that includes torque transfer components and piston rod head retention components that are integrated together as one part.

The torque transfer components of the multi-functional hub are configured to provide coupling between a drive shaft and a rotating group of the hydraulic pump/motor. The rotating group includes a cylinder block that has a plurality of cylinders and a plurality of piston rods adapted to slide axially within the plurality of cylinders of the cylinder block.

The piston rod head retention components of the multi-functional hub are configured to retain piston rod heads of the piston rods with respect to the drive shaft. The multi-functional hub is secured to the drive shaft such that the multi-functional hub and the drive shaft are adapted to rotate in unison with one another with torque being transferred therebetween.

The design complexity is reduced and allows the drive features to be more easily manufactured without increasing the component count within the bent-axis hydraulic pump/motor.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the description, illustrate several aspects of the present disclosure. A brief description of the drawings is as follows:

FIG. 1 is a side view of a bent-axis hydraulic pump/motor in accordance with principles of the present disclosure.

FIG. 2 is an opposite side view of the bent-axis hydraulic pump/motor of FIG. 1.

FIG. 3 is a perspective view showing a mounting flange and drive shaft at a first end of the bent-axis hydraulic pump/motor of FIG. 1.

FIG. 4 is a perspective view showing a valve block mounted at a second end of the bent-axis hydraulic pump/motor of FIG. 1.

FIG. 5 is an end view showing the first end of the bent-axis hydraulic pump/motor of FIG. 1.

FIG. 6 is an exploded view of the bent-axis hydraulic pump/motor of

FIG. 1

FIG. 7 is another exploded view of the bent-axis hydraulic pump/motor of

FIG. 1. FIG. 8 is a cross-sectional view of the bent-axis hydraulic pump/motor of

FIG. 1.

FIG. 9 is an enlarged view of a portion of the bent-axis hydraulic pump/motor of FIG. 8.

FIG. 10 is a perspective view of a multi-functional hub and drive shaft in accordance with the principles of the present disclosure.

FIGS. 11-14 are multiple views of the multi-functional hub of FIG. 10.

FIGS. 15-18 are multiple views of another example multi-functional hub in accordance with the principles of the present disclosure.

FIG. 19 is a cross-sectional view of an enlarged portion of the multifunctional hub and drive shaft of FIG. 9 showing a pivotal torque transfer interface.

FIG. 20 is a cross-sectional view of another example pivotal torque transfer interface.

FIG. 21 is a perspective view of an alternate multi-functional hub and drive shaft in accordance with the principles of the present disclosure.

FIGS. 22-25 are multiple views of the multi-functional hub of FIG. 21.

FIGS. 26-29 are multiple views of another alternate multi-functional hub in accordance with the principles of the present disclosure.

DETAILED DESCRIPTION

The present disclosure is directed to simplifying the design of a bent-axis hydraulic pump/motor by combining a multi-functional hub and drive components into one integrated part.

FIGS. 1-5 are perspective views of a bent-axis hydraulic pump/motor 10 in accordance with the principles of the present disclosure. The bent-axis hydraulic pump/motor 10 includes a housing 12 having a main housing body 12a. The main housing body 12a has a first end 11 and an opposite second end 13. A mounting flange 15 is provided at the first end 11 and a valve block 14 mounts to the second end 13 of the main housing body 12a.

FIGS. 6-7 are exploded views of the bent-axis hydraulic pump/motor 10. The bent-axis hydraulic pump/motor 10 includes an internal assembly 17 that is configured to mount within the housing 12. The internal assembly 17 includes a rotating group 28, a drive shaft 30 (e.g., input/output shaft), and a slide/valve plate 22 (e.g., hydraulic valve manifold). The bent-axis hydraulic pump/motor 10 can also include a multi-functional hub 32 (see FIG. 8) and a pivot link 34 (see FIG. 9).

The rotating group 28 includes a cylinder block 36 (see FIG. 8) that is rotatable about a rotating group axis X (see FIG. 19) relative to the valve block 14 and the slide/valve plate 22. The drive shaft 30 can be rotatable about a drive shaft axis Xi (e.g., axis of rotation)(see FIG. 19) that is angled relative to the rotating group axis X to provide pump/motor displacement when the drive shaft 30 and the rotating group 28 are rotated. The drive shaft 30 includes a first end 54 that has a torque input/output portion 19 that projects outwardly from the first end 11 of the main housing body 12a and a second end 56 that includes a drive flange 58.

The bent-axis hydraulic pump/motor 10 also includes an actuator 21 (e.g., a solenoid, a servo-device, etc.) that is actuated to change the angle of the rotating group 28 relative to the drive shaft 30 to modify the volume of hydraulic fluid that is displaced by the bent-axis hydraulic pump/motor 10 for each rotation of the drive shaft 30.

The valve block 14 includes a first service port 18 (e.g., an input/output port, hydraulic port) and a second service port 20 (e.g., an input/output port, hydraulic port) for allowing hydraulic fluid to flow through the rotating group 28 of the bent-axis hydraulic pump/motor 10. The bent-axis hydraulic pump/motor 10 can function as a pump under certain conditions and as a motor under other conditions. When the bentaxis hydraulic pump/motor 10 is operated as a hydraulic motor, higher pressure hydraulic fluid is directed into the motor through one of the first and second service ports 18, 20 and lower pressure hydraulic fluid exits the motor through the other of the first and second service ports 18, 20. The pressurized hydraulic fluid flowing through the motor drives rotation of the rotating group 28 which drives rotation of the drive shaft 30 such that torque can be output from the motor from the torque input/output portion 19 of the drive shaft 30. Thus, hydraulic pressure and hydraulic fluid flow is converted into torque by the motor. When the bent-axis hydraulic pump/motor 10 is operated as a hydraulic pump, torque is applied to the torque input/output portion 19 of the drive shaft 30 to drive rotation of the drive shaft 30 which in turn drives rotation of the rotating group 28. As the rotating group 28 is rotated, the rotating group 28 draws hydraulic fluid into the pump through one of the first and second service ports 18, 20 and pressurized hydraulic fluid is outputted from the rotating group 28 through the other of the first and second service ports 18, 20. Thus, torque is converted to hydraulic pressure and flow by the pump.

Referring to FIGS. 8-9, cross-sectional views of the bent-axis hydraulic pump/motor 10 is depicted. The cylinder block 36 of the rotating group 28 includes a plurality of cylinders 38 that are parallel to and circumferentially spaced about the rotating group axis X. The rotating group 28 also includes a plurality of piston rods 40 that each have a first end 42 with a first rod head 44 and a second end 46 with a second rod head 48. The first rod heads 44 at the first end 42 are adapted to slide axially within the plurality of cylinders 38 of the cylinder block 36. The second ends 46 are coupled to the drive flange 58 provided at the second end 56 of the drive shaft 30.

Each of the plurality of piston rods 40 can define an axially extending fluid passage 52 operable to communication pressurized fluid for lubrication purposes. The lubrication fluid which flows through the fluid passage 52 serves to lubricate the outer surface of the second rod head 48 as it pivots relative to the multi-functional hub 32. Each cylinder 38 terminates, at its rearward end in a fluid port 50. In a manner well known to those skilled in the art, each of the fluid ports 50 is in communication with one of the first or second hydraulic ports 18, 20, as the cylinder block 36 rotates.

The first hydraulic port 18 and the second hydraulic port 20 in cooperation with the slide/valve plate 22 allow hydraulic fluid to flow into and out of the cylinders 38 of the cylinder block 36 during rotation of the cylinder block 36 about the rotating group axis X. The slide/valve plate 22 includes a first curved slot 24 and a second curved slot 26 positioned on opposite sides of the rotating group axis X such that each curves about the rotating group axis X. The first curved slot 24 is in fluid communication with the first hydraulic port 18 and the second curved slot 26 is in fluid communication with the second hydraulic port 20. The first and second curved slots 24, 26 are adapted to curve about the rotating group axis X and do not rotate with the cylinder block 36. At a given point in time during operation of the bent-axis hydraulic pump/motor 10, the first curved slot 24 can provide fluid communication between the first hydraulic port 18 and half of the cylinders 38 and the second curved slot 26 can provide fluid communication with a remaining half of the cylinders 38. That is, during rotation of the cylinder block 36 about the rotating group axis X, each of the cylinders 38 can be in fluid communication with the first curved slot 24 for approximately 180 degrees of rotation of the cylinder block 36 and can be in fluid communication with the second curved slot 26 for approximately a remaining 180 degrees of rotation of the cylinder block 36.

Still referring to FIG. 8, an actuator link 27 (e.g., pin) is shown that couples the actuator 21 to the slide/valve plate 22. The actuator 21 is configured to move the actuator link 27 which causes the slide/valve plate 22 to slide along a curved surface of the valve block 14 to change the angle of the rotating group axis X relative to the drive shaft axis Xi to control the displacement of the pump.

A pivot link 84 is provided for transferring torque between the cylinder block 36 and the drive shaft 30 while concurrently allowing for relative pivotal movement between the drive shaft 30 and the cylinder block 36 to modify the angle defined between the drive shaft axis Xi and the rotating group axis X. When the drive shaft axis Xi is co-axially aligned with the rotating group axis X, the bent-axis hydraulic pump/motor 10 is adapted to provide zero displacement of hydraulic fluid upon rotation of the rotating group 28 about the rotating group axis X. This is because in the co-axial position, rotation of the rotating group 28 does not cause reciprocation of the piston rods 40 within the cylinders 38 of the cylinder block 36 (i.e., the piston rods have a stroke length of zero). In contrast, when the drive shaft 30 is angled relative to the rotating group axis X, the piston rods 40 are caused to reciprocate within the cylinders 38 of the cylinder block 36 as the rotating group 28 rotates about the rotating group axis X. The reciprocation stroke length of the piston rods 40 increases in direct proportion to the angle defined between the drive shaft axis Xi and the rotating group axis X. Thus, the displacement of the bent-axis hydraulic pump/motor 10 increases with the angle defined between the drive shaft axis Xi and the rotating group axis X.

Referring to FIG. 10, the drive flange 58 of the drive shaft 30 defines an axial face 60 that includes a plurality of rod head pockets 62 in which the second rod heads 48 of the piston rods 40 are received. The rod head pockets 62 can be unitary with the drive flange 58. The plurality of rod head pockets 62 can be circumferentially spaced about the drive shaft axis Xi. In certain examples, the drive flange 58 defining the plurality of rod head pockets 62 can be made from a bronze alloy suitable for pivotal engagement, under load, with the second rod heads 48, while maintaining good wear characteristics.

The multi-functional hub 32 includes a pivot link coupling sleeve 64 that has a first end 66 and an opposite second end 68. The first end 66 of the pivot link coupling sleeve 64 can be inserted into the second end 56 of the drive shaft 30. The multi-functional hub 32 can include a rod head retention flange 70 at the second end 68 that retains the second rod heads 48 of the piston rods 40 in the rod head pockets 62 of the drive flange 58. In one example, the rod head retention flange 70 can include a plurality of piston head tabs 70a separated by recesses 70b, although alternatives are possible. Portions of the rod head retention flange 70 coinciding with the recesses 70b are adapted to overlap the rod head pockets 62 to retain the second rod heads 48 therein.

In other examples, the rod head retention flange 70 may define holes that are adapted to encompass the second rod heads 48 of the piston rods 40.

In other examples, a flange without tabs or recesses can be used to overlap the rod head pockets 62 to retain the second rod heads 48 therein. The rod head retention flange 70 can be unitary (e.g., formed as a single piece) with the pivot link coupling sleeve 64.

In one example, the multi-functional hub 32 can be secured to the drive shaft 30 by fasteners 72 that extend axially through fastener holes 74 defined in the rod head retention flange 70 and into openings 76 defined in the axial face of the drive flange 58. It will be appreciated that the multi-functional hub 32 can be secured to the drive shaft 30 by other connecting techniques.

The multi-functional hub 32 can be co-axially aligned along the drive shaft axis Xi and can be secured to the drive shaft 30 such that the multi-functional hub 32 and the drive shaft 30 are adapted to rotate in unison with one another about the drive shaft axis Xi with torque being transferred between the drive shaft 30 and the multifunctional hub 32. The torque input-output end of the drive shaft 30 can be splined, include one or more torque transfer flats, or be keyed. The drive shaft 30 can be rotatably supported within the main housing body 12a by bearings 78. The bearings 78 allow the drive shaft 30 to rotate relative to the main housing body 12a about the drive shaft axis Xi. The bearings 78 can include a thrust bearing 78a that transfers axial load and a rotational bearing 78b. The rotation bearing 78b has an outer race 77a and an inner race 77b where the inner race 77b can rotate relative to the outer race 77a. During use, the inner race 77b is configured to press against the drive shaft 30 and the outer race 77a is configured to press against the housing 12 so that drive shaft 30 rotates relative to the housing 12.

Referring to FIGS. 11-14, a pivot link receiver 80 can be unitarily formed within the pivot link coupling sleeve 64 of the multi-functional hub 32. The pivot link receiver 80 includes a universal joint drive slot 82 in the pivot link coupling sleeve 64.

FIGS. 15-18 depict another example multi-functional hub 32a. The multifunctional hub 32a has similar features as the multi-function hub 32 previously described except for the universal joint drive slot 82. The multi-functional hub 32a includes a pivot link receiver 80a that has a tripode drive configuration with three drive slots 82a having curved sides for use with a tripode constant velocity joint.

Turning to FIG. 19, the bent-axis hydraulic pump/motor 10 includes a pivot link 84 for transferring torque between the multi-functional hub 32 and the cylinder block 36. The pivot link 84 includes a first end 86 and an opposite second end 88.

The first end 86 of the pivot link 84 is adapted to be coupled with the pivot link coupling sleeve 64 at a first pivotal torque transfer interface 90 for transferring torque between the pivot link 84 and the pivot link coupling sleeve 64 while concurrently permitting pivotal movement of the first end 86 of the pivot link 84 relative to the pivot link coupling sleeve 64.

The second end 88 of the pivot link 84 is adapted to be coupled with the cylinder block 36 at a second pivotal torque transfer interface 92 for transferring torque between the pivot link 84 and the cylinder block 36 while concurrently permitting pivotal movement of the second end 88 of the pivot link 84 relative to the cylinder block 36.

The pivot link 84 is configured to allow the cylinder block 36 and the drive shaft 30 to be pivotally moved relative to one another to vary a stroke length of the piston rods 40 with respect to the cylinders 38 of the cylinder block 36. When the rotating group 28 is coaxial with the axis of rotation Xi of the drive shaft 30, such would constitute the minimum displacement condition of the rotating group 28. In the minimum displacement condition, there is substantially zero flow output from the bent-axis hydraulic pump/motor 10 (when being used as a pump) per revolution of the drive shaft 30.

The first and second ends 86, 88 of the pivot link 84 include a cross-pin 94 with a first end 96 and an opposite second end 98. The first and second ends 96, 98 of the cross-pin 94 are configured to engage the joint drive slot 82 defined in the pivot link receiver 80 to allow the transfer of torque between the multi-functional hub 32 and the pivot link 84 while concurrently allowing pivotal movement of the pivot link 84 relative to the multi-functional hub 32.

As the pivot link 84 pivots, the first end 86 of the pivot link 84 is configured to ride along a flat surface 104 (see FIGS. 8-9) of a spring loaded seat 106. The spring loaded seat 106 is adapted to engage the first end 86 of the pivot link 84.

In other examples, the pivot link 84 can be configured to ride along a curved surface 104a of a spring loaded seat 106a. The spring loaded seat 106a can define a passage 108 for receiving lubricant to lubricate the curved surface 104a on which the first end 86 of the pivot link 84 rides.

A spring 110 can be positioned in a bore 112 of the drive shaft 30. The spring 110 is designed to provide constant contact of the spring loaded seat 106 with the first end 86 of the pivot link 84.

FIG. 20 shows an alternate configuration with a cross-pin 94a that has a smaller cross diameter than the cross-pin 94. The cross-pin 94a includes blocks 102 that can be pressed fit at the first and second ends 96, 98. In certain examples, the blocks 102 can have a sliding fit at the first and second ends 96, 98. The blocks 102 are shaped to mount within the universal joint drive slot 82 to provide torque transfer and pivotal movement.

FIG. 21 depicts an alternate multi-functional hub 32b and drive shaft 30a in accordance with the principles of the present disclosure. The multi-functional hub 32b has similar features as the multi-function hubs 32, 32b previously described except the rod head retention flange 70c does not include tabs or recesses to overlap the rod head pockets 62 for retaining the second rod heads 48 therein. The multi-functional hub 32b can be simpler and easier to manufacture, while still providing adequate piston retention. The rod head retention flange 70c of the multi-functional hub 32b includes a chamfered edge 114 that is configured to overlap portions of the second rod heads 48 positioned in the rod head pockets 62 of the drive flange 58a to hold the second rod heads 48 in place. The chamfered edge 114 is arranged and configured to provide adequate retention of the second rod heads 48 within the rod head pockets 62.

FIGS. 22-25 are multiple views of the multi-functional hub 32b. The multi-functional hub 32b can be secured to the drive shaft 30a by fasteners 72 that extend axially through fastener holes 74 defined in the rod head retention flange 70c and into openings 76 defined in the axial face of the drive flange 58a of the drive shaft 30a. It will be appreciated that the multi-functional hub 32b can be secured to the drive shaft 30a by other connecting techniques.

The multi-functional hub 32b includes a pivot link coupling sleeve 64 that has a first end 66 and an opposite second end 68. The first end 66 of the pivot link coupling sleeve 64 can be inserted into the second end 56 of the drive shaft 30a. The rod head retention flange 70c can be unitary (e.g., formed as a single piece) with the pivot link coupling sleeve 64.

A pivot link receiver 80b can be unitarily formed within the pivot link coupling sleeve 64 of the multi-functional hub 32b. The pivot link receiver 80b includes a universal joint drive slot 82b in the pivot link coupling sleeve 64.

A cross-pin 94 can be configured to engage the universal joint drive slot 82b defined in the pivot link receiver 80b to allow the transfer of torque between the multi-functional hub 32b and the pivot link 84 while concurrently allowing pivotal movement of the pivot link 84 relative to the multi-functional hub 32b.

The universal joint drive slot 82b can define grooves 116. The grooves 116 are designed to make the manufacturing process easier by avoiding the need to tool sharp corners in the universal joint drive slot 82b of the pivot link receiver 80b, which can become a stress concentration area. The grooves 116 can also help to provide clearance for the cross-pin 94. FIG. 26 depicts an alternate multi-functional hub 32c in accordance with the principles of the present disclosure. The multi-functional hub 32c has similar features as the multi-function hub 32b previously described except the rod head retention flange 70d includes a radius around the perimeter.

Turning to FIGS. 27-29, the rod head retention flange 70d of the multifunctional hub 32c includes a radius 118 around the rod head retention flange 70d perimeter and a chamfered edge 120 that extends in an opposite direction from the radius 118. The radius 118 is configured to overlap portions of the second rod heads 48 positioned in the rod head pockets 62 of the drive flange 58a to hold the second rod heads 48 in place. The radius 118 is arranged and configured to provide adequate retention of the second rod heads 48 within the rod head pockets 62. That is, the radius 118 helps to improve the retention of the second rod heads 48 in the rod head pockets 62 because of the increased overlap provided by the radius 118 can make the interface stronger. Furthermore, the radius 118 can be less sensitive to manufacturing variation. Preferably the radius is less than 10 mm. More preferably the radius is between 6.0 and 9.0 mm and in particular between 7.0 and 8.0 mm or even 8.0 to 8.75 mm.

The multi-functional hub 32c includes a pivot link coupling sleeve 64 that has a first end 66 and an opposite second end 68. The first end 66 of the pivot link coupling sleeve 64 can be inserted into the second end 56 of the drive shaft 30a. The rod head retention flange 70d can be unitary (e.g., formed as a single piece) with the pivot link coupling sleeve 64.

A pivot link receiver 80c can be unitarily formed within the pivot link coupling sleeve 64 of the multi-functional hub 32c. The pivot link receiver 80c includes a universal joint drive slot 82c in the pivot link coupling sleeve 64.

Similar to the multi-functional hub 32b described above, the cross-pin 94 can be configured to engage the universal joint drive slot 82c defined in the pivot link receiver 80c to allow the transfer of torque between the multi-functional hub 32c and the pivot link 84 while concurrently allowing pivotal movement of the pivot link 84 relative to the multi-functional hub 32c. The universal joint drive slot 82c can also define grooves 116 as described above. The multi-functional hub 32c can be secured to the drive shaft 30a by fasteners 72 that extend axially through fastener holes 74 defined in the rod head retention flange 70c and into the openings 76 defined in the axial face of the drive flange 58a of the drive shaft 30a. It will be appreciated that the multi-functional hub 32c can be secured to the drive shaft 30a by other connecting techniques.

The various examples described above are provided by way of illustration only and should not be construed to limit the scope of the present disclosure. Those skilled in the art will readily recognize various modifications and changes that may be made with respect to the examples and applications illustrated and described herein without departing from the true spirit and scope of the present disclosure.