The present description relates generally to an axial piston assembly. More specifically, the present disclosure relates to an adjustment screw and a bearing element for adjusting a position of a distribution plate of an axial piston assembly.
Hydraulic axial piston assemblies are often used as stand-alone pumps, hydraulic motors, or compressors. A hydraulic axial piston assembly may comprise an axial piston system and a distributor system. The axial piston system may include a plurality of cylinders arranged in a circular array around a central axis. Each cylinder may contain a reciprocating piston. Different mechanisms may be used to drive the reciprocating motion of the pistons in their cylinders, such as swashplate drives. A swashplate is in effect a cam surface attached to and rotating with a crankshaft that drives or is driven by the reciprocating linear motion of the pistons. Each piston may have one or more bearings attached to it that slide or roll over the surface of the swashplate cam surface.
The reciprocating linear motion of the pistons along their longitudinal axes may drive fluid both into and out of the cylinders of the axial piston system through a distributor plate. The response of the axial piston system depends on the rotational position of the distributor plate relative to a body of the distributor system. In some examples, adjusting the rotational position of the distributor plate may require the disassembly of at least a portion of the hydraulic axial piston assembly.
Other attempts to avoid disassembling the hydraulic axial piston assembly when changing the position of the distributor plate include rotating the distributor plate via an external screw and eccentric pin that is centered directly on the distributor plate. However, the inventors herein have recognized potential issues with such systems. Such systems may require an increased thickness of the distributor plate to accommodate for the rotation of the eccentric pin around the rotational axis of the external screw. A distributor plate with increased thickness may have increased manufacturing cost and require a larger packaging space. Additionally, with only the eccentric pin rotationally coupling the adjustment screw to the distributor plate, the rotational forces of the external screw may be discharged directly on the eccentric pin, increasing the rate at which the eccentric pin may degrade.
In one example, the issues described above may be addressed by a hydraulic axial piston assembly comprising a distributor plate, a bearing element directly and orthogonally connected to a side of the distributor plate, and an adjustment screw orthogonally connected to the bearing element, where the adjustment screw is externally accessible and manually rotatable to adjust a timing angle of the distributor plate. The externally accessible adjustment screw may allow the rotatable distributor plate to be rotated to vary the behavior of the hydraulic axial piston assembly without any part of the hydraulic axial piston assembly having to be disassembled and/or reassembled. Further, the adjustment screw may discharge forces on the bearing element, instead of directly onto an eccentric pin, which may reduce degradation of the eccentric pin.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.
As shown in
The distributor body 102 may include an adjustment screw bore 122 and a bearing element bore 116. The adjustment screw bore 122 may be cylindrical and may extend into the distributor body 102 along an axis parallel to the y-axis. The bearing element bore 116 may be cylindrical and may extend into the distributor body 102 along an axis parallel to the x-axis (e.g., the bearing element bore 116 may be orthogonal to the adjustment screw bore 122). Further, the distributor body 102 may include an adjustment screw 118 and a bearing element 111, positioned within the adjustment screw bore 122 and the bearing element bore 116, respectively. The bearing element 111 may comprise an eccentric pin 112 and a bearing body 114, where a portion of the eccentric pin 112 may be positioned within the bearing body 114. Similarly, a portion of the eccentric pin 112 may be in face sharing contact with the distributor plate 106, as described in reference to
The distributor body 102 may include a shaft bore 104, where the shaft bore 104 is circular and extends into the distributor body along a central axis 108. The shaft bore 104 may be configured to accommodate a shaft 109. In some examples, the shaft 109 may be a crankshaft. The shaft 109 may be positioned within the shaft bore 104 such that the shaft 109 may extend into the distributor body 102. The longitudinal axis of the shaft 109 may be aligned with the central axis 108. Further, the shaft 109 may be configured to rotate around its longitudinal axis (e.g., around the central axis 108) within the shaft bore 104 of the distributor body 102.
The axial piston system 105 may include a shaft bore 136, a system body 107, a swashplate 130, a cylinder block 134, and a piston 124. The system body 107 of the axial piston system 105 may include an inner volume 113. The swashplate 130, the cylinder block 134, and the piston 124 may each be positioned within the inner volume 113 of the system body 107. Further, the shaft bore 136 may extend through the axial piston system 105 along the central axis 108.
The cylinder block 134 may be an annulus that is positioned circumferentially around the shaft bore 136 and that has a longitudinal axis parallel to the central axis 108. The cylinder block 134 may include a cylinder bore 120. The cylinder bore 120 may be circular and extend into the cylinder block 134 from a first side 135 of the cylinder block 134, where the first side 135 is positioned distal the distributor system 100. A first end 121 of the cylinder bore 120 (e.g., the end of the cylinder bore 120 that is positioned closest to the distributor system 100) may narrow into a fluid channel 128, which may be circular and extend from the first end 121 of the cylinder bore 120 to a second end 137 of the cylinder block 134. The second end 137 of the cylinder block 134 may be in face sharing contact with the distributor plate 106. The fluid channel 128 may fluidly couple the axial piston system 105 (e.g., the cylinder block 134) to the distributor system 100. As such, fluid may travel between the cylinder bore 120 and the distributor system 100 as described herein.
At least a portion of the piston 124 may be positioned within the cylinder bore 120 such that an outer circumferential surface of the piston 124 is in face sharing contact with the inner surface of the cylinder bore 120. The piston 124 may include a coupling end 126 that is positioned outside of the cylinder bore 120. The coupling end 126 may couple to a slipper 132 that is positioned in face sharing contact with the swashplate 130. In some examples, the slipper 132 may not be rigidly coupled to the swashplate 130, and instead may be coupled to the swashplate 130 in such a way that the slipper 132 may translate across a surface of the swashplate 130. As such, if the swashplate 130 were to rotate around the central axis 108, the slipper 132 may not rotate but instead may stay in the same position relative to the y-axis and z-axis. The swashplate 130 may be oriented such that the swashplate 130 is not orthogonal to the longitudinal axis of the shaft 109 (e.g., not orthogonal to the central axis 108). As such, one portion of the swashplate 130 may be positioned closer to the cylinder block 134 than another portion of the swashplate 130, relative to the x-axis.
The shaft 109 may extend from the shaft bore 104 of the distributor body 102 into the shaft bore 136 of the axial piston system 105 along the central axis 108. In some examples, the shaft 109 may couple to the swashplate 130. As the shaft 109 rotates around the central axis 108, the swashplate 130 may rotate around the central axis 108 simultaneously (e.g., with the same rotational speed and in the same direction) with the shaft 109. The slipper 132 may not be rigidly coupled to the swashplate 130 and therefore may not rotate around the central axis 108 with the swashplate 130 and the shaft 109. Due to the orientation of the swashplate 130 relative to the cylinder block 134 (e.g., oriented non-orthogonally), rotation of the swashplate 130 around the central axis may drive a reciprocating linear motion of the slipper 132 along an axis parallel to the x-axis. Similarly, the slipper 132 may drive a reciprocating linear motion of the piston 124 within the cylinder bore 120 via the coupling end 126 of the piston 124. The reciprocating liner motion of the piston 124 in the cylinder bore 120 may drive displacement of fluid through the fluid channel 128. As the swashplate 130 pushes the piston 124 toward bottom dead center (e.g., away from the distributor system 100) within the cylinder bore 120, fluid may be forced into the cylinder bore 120 through the fluid channel 128. Similarly, as the swashplate 130 pushes the piston 124 toward top dead center (e.g., toward the distributor system 100) within the cylinder bore 120, fluid may be forced out of the cylinder bore 120 and through the fluid channel 128. Any fluid that flows through the axial piston system 105 may also flow through the distributor plate 106 and the distributor body 102, as described in reference to
In other examples, the shaft 109 may couple to the cylinder block 134 and not to the swashplate 130. As the shaft 109 rotates around the central axis 108, the cylinder block 134 may rotate around the central axis 108 simultaneously with the shaft 109. The positon of the piston 124 within the cylinder bore 120 may drive the piston 124 to rotate around the central axis 108 simultaneously with the cylinder block 134 and the shaft 109. Similarly, the coupling end 126 of the piston 124 may drive the slipper 132 to rotate around the central axis 108 simultaneously with the piston 124, the cylinder block 134, and the shaft 109. As the slipper 132 rotates around the central axis 108, the slipper 132 may remain in face sharing contact with the swashplate 130. The orientation of the swashplate 130 relative to the cylinder block 134 may drive a reciprocating linear motion of the slipper 132 along an axis parallel to the x-axis as the slipper 132 rotates around the central axis 108. Similarly, the slipper 132 may drive a reciprocating linear motion of the piston 124 within the cylinder bore 120 as the piston 124 rotates around the central axis 108. As the piston 124 moves toward bottom dead center (e.g., away from the distributor system 100) within the cylinder bore 120, fluid may be forced into the cylinder bore 120 through the fluid channel 128. Similarly, as the piston 124 moves toward top dead center (e.g., toward the distributor system 100) within the cylinder bore 120, fluid may be forced out of the cylinder bore 120 and through the fluid channel 128. Any fluid that flows through the axial piston system 105 may also flow through the distributor plate 106 and the distributor body 102, as described in reference to
In some examples, the axial piston system 105 may include a control piston (not shown). The control piston may couple to an outer surface of the system body 107 of the axial piston system 105 and may be positioned above the swashplate 130, relative to the y-axis. The control piston may exert a force on the swashplate 130 in order to change the angle of the swashplate 130 relative to the central axis 108. As the angle of the swashplate 130 changes, the stroke of the piston 124 within the cylinder bore 120, and therefore the amount of fluid displaced by the piston 124, may change as well. In some examples, the control piston may not control the angle of the swashplate 130 but instead may sense the current displacement of the axial piston system 105 and signal to one or more additional components to change the angle of the swashplate 130.
Although the illustrated example of
As shown in
The distributor body 102 may include a front surface 224 and a top surface 226, with the top surface 226 being orthogonal to the front surface 224. The top surface 226 may be an external surface of the distributor body 102. The top surface 226 may include a fluid inlet passage 228 and a fluid outlet passage 230, which may be an inlet port and outlet port of the hydraulic axial piston assembly, respectively, though the position of the inlet port and outlet port may be swapped without departing from the scope of this disclosure. In some examples, the fluid inlet passage 228 and the fluid outlet passage 230 may be positioned on raised areas of the top surface 226. Additionally, the top surface 226 may include an adjustment screw bore 122 (e.g., a first bore). The adjustment screw bore 122 may extend from the top surface 226 into the distributor body 102 along an axis that is parallel to the y-axis.
The front surface 224 may be a coupling surface, and as such may be configured to couple to the axial piston system to facilitate distribution of fluid to and from and the axial piston system. In some examples, the shaft bore 104 may be included on the front surface 224 of the distributor body 102. The shaft bore 104 may be circular and extend along an axis parallel to the x-axis, such as a central axis 108 of
As each piston rotates around the longitudinal axis of the shaft, the swashplate may cause the piston to undergo reciprocating linear motion within a cylinder bore. The reciprocating linear motion of a piston within a cylinder bore may drive the displacement of fluid through the distributor system 100. As the swashplate pushes the piston toward bottom dead center (BDC), fluid may be forced into the cylinder bore. Similarly, as the swashplate pushes the piston towards top dead center (TDC), fluid may be forced out of the cylinder bore.
The front surface 224 may also include a plurality of body ports 210. The plurality of body ports 210 may comprise a first body port 210a, a second body port 210b, a third body port 210c, a fourth body port 210d, a fifth body port 210e, and a sixth body port 210f. In some examples, the first body port 210a, the second body port 210b, and the third body port 210c may be inlet ports. Similarly, in some examples, the fourth body port 210d, the fifth body port 210e, and the sixth body port 210f may be outlet ports. Each port in the plurality of body ports 210 may be arranged such that the plurality of body ports 210 are positioned concentrically around the shaft bore 104. In other examples, the plurality of body ports 210 may include a different number of total ports comprising one or more inlet ports and one or more outlet ports.
Each of the first body port 210a, the second body port 210b, and the third body port 210c (e.g., each of the inlet ports in the plurality of body ports 210) may be connected to the fluid inlet passage 228 on the top surface 226 of the distributor body 102. As such, fluid may flow from the fluid inlet passage 228 to each of the first body port 210a, the second body port 210b, and the third body port 210c. Similarly, each of the fourth body port 210d, the fifth body port 210e, and the sixth body port 210f (e.g., each of the outlet ports in the plurality of body ports 210) may be connected to the fluid outlet passage 230 on the top surface 226 of the distributor body 102. As such, fluid may flow from each of the fourth body port 210d, the fifth body port 210e, and the sixth body port 210f to the fluid outlet passage 230.
The front surface 224 of the distributor body 102 may not be completely flat (e.g., planar) and may include one or more recessed areas, such as a recessed area 260. The recessed area 260 may be recessed into the front surface 224 an amount in a range of 0.08+/−0.01 cm. A first portion 262 of the recessed area 260 may be an annulus positioned immediately surrounding the shaft bore 104 on the front surface 224. As such, the first portion 262 of the recessed area 260 may be positioned between the shaft bore 104 and the plurality of body ports 210 on the front surface 224. A second portion 264 of the recessed area 260 may be an annulus positioned surrounding the plurality of body ports 210 on the front surface 224. In this way, the plurality of body ports 210 may be positioned on an area of the front surface 224 that is surrounded by the recessed area 260 but is not itself recessed. Additionally, a bearing element bore 116 may be positioned at the topmost point, relative to the y-axis, of the second portion 264 of the recessed area 260.
The first portion 262 and the second portion 264 of the recessed area 260 may be connected by a third portion 266 and a fourth portion 268 of the recessed area 260. The third portion 266 of the recessed area 260 may comprise two oblong recesses extending downwards (e.g., relative to the y-axis) from the first portion 262 and passing through the second portion 264. The first oblong recess of the third portion 266 may be laterally offset (e.g., relative to the z-axis) from the second oblong recess of the third portion 266. The bottommost edge (e.g., relative to the y-axis) of each of the oblong recesses of the third portion 266 may be rounded.
The fourth portion 268 of the recessed area 260 may comprise two oblong recesses extending upwards (e.g., relative to the y-axis) from the first portion 262 and passing through the second portion 264. The first oblong recess of the fourth portion 268 may be laterally offset (e.g., relative to the z-axis) from the second oblong recess of the fourth portion 268. The topmost edge, (e.g., relative to the y-axis) of each of the oblong recesses of the fourth portion 268 may be rounded. Additionally, the bearing element bore 116 may be positioned on the front surface 224 in between the first oblong recess and the second oblong recess of the fourth portion 268 of the recessed area 260.
As illustrated in
In some examples, the distributor plate 106 may include a central bore 258 which may have a circular shape. The central bore 258 may pass through the center of the first flat surface 232 and the center of the second flat surface 306, relative to the y-z plane, of the distributor plate 106. The central bore 258 may accommodate the shaft that passes through the shaft bore 104 of the distributor body 102. Additionally, the distributor plate 106 may include a plurality of plate ports 208. The plurality of plate ports 208 may comprise a first plate port 208a, a second plate port 208b, a third plate port 208c, a fourth plate port 208d, a fifth plate port 208e, and a sixth plate port 208f. Each port in the plurality of plate ports 208 may pass through the first flat surface 232 and the second flat surface 306 of the distributor plate 106, and may be arranged such that the plurality of plate ports 208 are distributed concentrically around the central bore 258. As shown in
In some examples, the first plate port 208a, the second plate port 208b, and the third plate port 208c may be inlet ports. Similarly, in some examples, the fourth plate port 208d, the fifth plate port 208c, and the sixth plate port 208f may be outlet ports. In other examples, the plurality of body ports 210 may include a different number of total ports comprising one or more inlet ports and one or more outlet ports.
Each port in the plurality of plate ports 208 may be fluidly coupled to either the fluid inlet passage 228 or the fluid outlet passage 230 on the top surface 226 via a port in the plurality of body ports 210. The first plate port 208a, the second plate port 208b, the third plate port 208c, the fourth plate port 208d, the fifth plate port 208e, and the sixth plate port 208f may fluidly couple to the first body port 210a, the second body port 210b, the third body port 210c, the fourth body port 210d, the fifth body port 210e, and the sixth body port 210f, respectively. As such, fluid may flow from the fluid inlet passage 228, through each inlet port in the plurality of body ports 210, to each of the first plate port 208a, the second plate port 208b, and the third plate port 208c (e.g., to each inlet port in the plurality of plate ports 208). Similarly, fluid may flow from each of the fourth plate port 208d, the fifth plate port 208c, and the sixth plate port 208f (e.g., from each outlet port in the plurality of plate ports 208), through each outlet port in the plurality of body ports 210, and to the fluid outlet passage 230.
The reciprocating linear motion of the pistons of the axial piston system may actuate the flow of fluid through the distributor system 100, as described above. Additionally, fluid may be pumped into or out of a cylinder when the cylinder is aligned with a port in the plurality of plate ports 208. As the piston moves down toward BDC, fluid may be forced into the cylinder when the cylinder passes over one of the three inlet ports of the plurality of plate ports 208. Similarly, as the piston moves from BDC toward TDC, fluid may be forced out of the cylinder when the cylinder passes over one of the three outlet ports of the plurality of plate ports 208.
The second flat surface 306 of the distributor plate 106 may be oriented such that it is parallel to the front surface 224 of the distributor body 102. As shown in
As illustrated in
The distributor plate 106 may include one or more tapered edges on the plurality of plate ports 208, such as the first tapered edge 408 on the first plate port 208a. As illustrated in
As shown in
The distributor system 100 may include the adjustment screw 118 and a lock nut 220. The adjustment screw 118 may comprise a body 246, a longitudinal end 248, and a coupling end 250, where the body 246 may be intermediate the longitudinal end 248 and the coupling end 250. As such, the longitudinal end 248 may be couple to the body 246, and the body 246 may couple to the coupling end 250. In some examples, the lock nut 220 may be a sealing lock nut.
Referring to
The front surface 238 of the bearing body 114 may be oriented in the same direction as the front surface 224 of the distributor body 102 (e.g., pointed along the x-axis). Additionally, the front surface 238 of the bearing body 114 may be coplanar with the front surface 224, such that both the front surface 238 and the front surface 224 may extend in the x-z plane. In some examples, the front bore 252 may extend approximately 50% of the way into the bearing body 114 along an axis parallel to the x-axis. The front bore 252 may accommodate the base 242 of the eccentric pin 112, while the head 244 of the eccentric pin 112 may extend outwards past the front surface 238 of the bearing body 114, relative to the x-axis.
The base 242 of the eccentric pin 112 (e.g., the front bore 252) may be positioned between an upper lip 310 of the bearing body 114 and a lower portion 312 of the bearing body 114. The upper lip 310 may be positioned above (e.g., relative to the y-axis) the base 242 of the eccentric pin 112 such that the upper lip 310 is between the base 242 and the top (e.g., relative to the y-axis) of the inner surface of the bearing element bore 116. The upper lip 310 may be thinner (e.g., relative to the y-axis) than the lower portion 312 of the bearing body 114, such that the position of the base 242 of the eccentric pin 112 is eccentrically positioned relative to the y-axis.
In some examples, the head 244 of the eccentric pin 112 may have a rectangular shape when viewed from the side, as shown in
As illustrated in
The base 242 of the eccentric pin 112 may be positioned within the front bore 252 of the bearing body 114. As such, the eccentric pin may be positioned eccentrically in the bearing body 114 (e.g., closer to a top of the bearing body 114 than a bottom of the bearing body 114). The base 242 of the eccentric pin 112 may be in face sharing contact with the inner surface of the front bore 252 such that the eccentric pin 112 is unable to move translationally within the bearing body 114. However, the eccentric pin 112 may rotate around its longitudinal axis (e.g., an axis parallel to the x-axis) within the front bore 252. In this way, the notch 256 of the distributor plate 106 may accommodate the head 244 of the eccentric pin 112 while the bearing body 114 and/or the distributor plate 106 rotate around their respective rotational axes.
As shown in
The coupling end 250 of the adjustment screw 118 may be spherical in shape and may extend from the body 246 of the adjustment screw 118 via a connector 304. The connector 304 may have a smaller radius than either the adjustment screw 118 or the coupling end 250. In some examples, the size and shape of the coupling end 250 and the connector 304 may allow the coupling end 250 to lock into a slot (e.g., the coupling end 250 may be prevented from translational movement in one or more directions). For example, the coupling end 250 may be inserted vertically (e.g., along an axis parallel to the y-axis) into a bore (e.g., the top bore 254) and moved translationally in a direction perpendicular to the longitudinal axis of the adjustment screw 118 (e.g., perpendicular to the y-axis). In this way, the connector 304 may be positioned into a notch or slot (e.g., an opening) with a radius smaller than the radius of the coupling end 250. As such, the coupling end 250 may not be able to translate vertically (e.g., along an axis parallel to the y-axis) and the adjustment screw 118 may be locked in place by the notch or slot.
The body 246 of the adjustment screw 118 may have a cylindrical shape and may be positioned (e.g., housed) within the adjustment screw bore 122. The adjustment screw bore 122 may be open to atmosphere (e.g., externally accessible) through the top surface 226 (e.g., an external surface) of the distributor body 102. The adjustment screw 118 may be shorter than the adjustment screw bore 122, and therefore the adjustment screw 118 may fit completely into the adjustment screw bore 122. The body 246 may include threads that allow the adjustment screw 118 to couple to the adjustment screw bore 122. Similarly, at least a portion of the adjustment screw bore 122 may include threads that couple to the threads on the body 246 of the adjustment screw 118. In this way, the body 246 of the adjustment screw 118 may be in face sharing contact with the adjustment screw bore 122. In some examples, as shown in
As illustrated in
Thus, the adjustment screw 118 may be rotated by a suitable tool positioned in the tool slot 302 of the longitudinal end 248. In turn, the coupling end 250 of the adjustment screw 118 may rotate and translate at least a portion of the rotation into the bearing element 111 (e.g., the adjustment screw 118 may drive rotation of the bearing element 111) via the bearing body 114. The bearing body 114 may rotate along an axis orthogonal to the axis of rotation of the adjustment screw 118. As such, the eccentric pin 112 may rotate around the axis of rotation of the bearing body 114 simultaneously (e.g., with the same rotational speed and in the same direction) with the bearing body 114. The bearing body 114 may reduce the amount of force discharged onto the eccentric pin 112 via the adjustment screw 118, and may therefore reduce degradation of the eccentric pin 112.
The head 244 of the eccentric pin 112 may directly engage with the surfaces of the distributor plate 106 that form the notch 256. As such, the eccentric pin 112 may rotationally couple to the notch 256 of the distributor plate 106. A front surface, a bottom surface, a first side surface, and a second side surface of the head 244 may be in face sharing contact with the notch 256, allowing rotational force to be transferred from the eccentric pin 112 to the distributor plate 106 without requiring an increased thickness of the distributor plate 106. In this way, the distributor plate 106 may rotate around an axis of rotation (e.g., around central axis 108) that is parallel to, but offset from, the axis of rotation of the bearing body 114. Due to the offset rotational axes of the bearing body 114 and the distributor plate 106, as well as the position of the head 244 of the eccentric pin 112 in the notch 256, the eccentric pin 112 may also rotate within the front bore 252 around the longitudinal axis of the eccentric pin. Therefore, by rotating the adjustment screw 118 an operator may cause the distributor plate 106 to rotate. As the distributor plate 106 rotates, the behavior of the distributor system 100 may vary by changing the working pressure and timing angle of fluid passing through the distributor system 100.
At 602, method 600 may include rotating an adjustment screw with an external tool. The external tool may be a screwdriver, hex key, or other suitable tool. The adjustment screw may be a non-limiting example of the adjustment screw 118 of
At 604, method 600 may include rotating a coupling end of the adjustment screw within a bearing element. The coupling end of the adjustment screw may be positioned on the longitudinal end of the adjustment screw that is distal the tool slot and thus as the adjustment screw rotates within the adjustment screw bore, the coupling end of the adjustment screw may also rotate simultaneously (e.g., with the same rotational speed and in the same direction) with the rotation of the tool end. The coupling end may be positioned within a top bore of a bearing body, such as within the top bore 254 of the bearing body 114.
At 606, method 600 may include rotating the bearing body and the eccentric pin via the adjustment screw. The adjustment screw may be rotationally coupled to the bearing body via the coupling end and the top bore. As such, a rotation of the adjustment screw via an external tool may drive a rotation of the bearing body within the bearing element bore. In some examples, the axis of rotation of the bearing body may be orthogonal to the axis of rotation of the adjustment screw. A portion of the eccentric pin may be positioned within the bearing body, and as such, the eccentric pin may be rotationally coupled to the bearing body. In this way, the eccentric pin may rotate around the rotational axis of the bearing body when the bearing body is rotated via the adjustment screw.
At 608, method 600 may include rotating a distributor plate coupled to the distributor body via the eccentric pin. As explained previously, the distributor plate may include a notch (e.g., notch 256 of
As the distributor plate of the distributor system rotates, the position of the plurality of plate ports on the distributor plate may be varied relative to a plurality of body ports (e.g., the plurality of body ports 210) on the distributor body of the distributor system. Fluid may be pumped first through a port in the plurality of body ports and then immediately through a port in the plurality of plate ports (e.g., fluid flowing out of the distributor system), or vice versa (e.g., fluid flowing into the distributor system). When the alignment between a port in the plurality of plate ports and a corresponding port in the plurality of body ports changes, the area that fluid can flow through to enter or exit the axial piston system may also change. The volume of each cylinder in an axial pump system may remain fixed, and therefore the volume of fluid displaced by a reciprocating piston within the cylinder may also remain fixed. Thus, if the alignment between the plurality of plate ports and the plurality of body ports changes, the velocity at which fluid displaces into and out of each cylinder of the axial piston system may change. As such, the pressure of fluid as it is pumped by the distributor system may vary based on the orientation of the plurality of plate ports relative to the plurality of body ports.
More specifically, as the distributor plate rotates, the alignment between the plurality of plate ports and the plurality of body ports may change. When the alignment between a port in the plurality of plate ports and a corresponding port in the plurality of body ports changes, the area that fluid can flow through to enter or exit the axial piston system may also change. The volume of each cylinder in an axial pump system may remain fixed, and therefore the volume of fluid displaced by a reciprocating piston within the cylinder may also remain fixed. Thus, if the plurality of plate ports becomes less aligned with the plurality of body ports (e.g., the fluid path becomes more constricted), the pressure drop across the distributor plate may increase. Similarly, if the plurality of plate ports becomes more aligned with the plurality of body ports (e.g., the fluid path becomes less constricted), the pressure drop across the distributor plate may decrease. Additionally, the rotation of the distributor plate may adjust the timing angle of the fluid that is pumped by the axial piston system. A change in the timing angle of fluid that pumped into/out of the cylinders through the three separate inlet ports and three separate outlet ports may cause the fluid to pulsate and may affect the amount of noise created by the axial piston system and distributor system.
Each behavior exhibited by the distributor system may illustrate the movement of a single piston relative to a given position of the distribution plate during operation of the hydraulic axial piston assembly. As the position of the piston changes relative to a given position on the distributor plate, the timing of the hydraulic axial piston assembly may change. As such, an x-axis of graph 700 may represent a position along a first axis and a y-axis of the graph 700 may represent a position along a second axis, where the second axis is orthogonal to the first axis. In some examples, the x-axis of graph 700 may represent a lateral position of the piston (e.g., an axis parallel to the plane of the distributor plate), and the y-axis of the graph 700 may represent a longitudinal position of the piston (e.g., an axis perpendicular to the plane of the distributor plate).
The graph 700 may include a first behavior 702 and a second behavior 708, which may represent a first extreme behavior and a second extreme behavior of the distributor system, respectively. The first behavior 702 may be exhibited by the distributor system when a distributor plate of the distributor system is oriented in a first extreme position. The distributor plate may be configured to rotate through a range of angles (e.g., −10 to 10 degrees, where 0 degrees is the default position shown in
Additionally, the graph 700 may include a first intermediate behavior 704 and a second intermediate behavior 706. The first intermediate behavior 704 may be exhibited by the distributor system when the distributor plate is oriented in a position intermediate the first extreme position and the second extreme position. As such, the movement of the piston during the first intermediate behavior 704 may occur at a position lower than the first behavior 702 but higher than the second behavior 708 on the graph 700, relative to the y-axis. Similarly, the second intermediate behavior 706 may be exhibited by the distributor system when the distributor plate is oriented in a position intermediate the first intermediate position and the second extreme position. As such, the movement of the piston during the second intermediate behavior 706 may occur at a position lower than the first intermediate behavior 704 but higher than the second behavior 708 on the graph 700, relative to the y-axis.
Each of the first behavior 702, second behavior 708, first intermediate behavior 704, and second intermediate behavior 706 may occur when the distributor plate is oriented in a different rotational position. The position of the distributor plate, and therefore the distributor timing, may also affect the position and/or reaction of a control piston. In turn, the control piston may at least in part affect the relationship between an operating pressure of the axial piston system and an amount of overturning torque on a swashplate of the axial piston system. The amount of overturning torque on the swashplate may at least in part determine the amount of fluid displaced by the axial piston system.
The graph 710 may include a first relationship 712, which may correspond to the first behavior 702 of the graph 700 of
The graph 710 may include a fourth relationship 718, which may correspond to the second behavior 708 of the graph 700 of
The graph 710 may include a second relationship 714, which may correspond to the first intermediate behavior 704 of the graph 700 of
The graph 710 may include a third relationship 716, which may correspond to the second intermediate behavior 706 of the graph 700 of
As illustrated in
The disclosure also provides support for a hydraulic axial piston assembly, comprising: a distributor plate, a bearing element directly and orthogonally connected to a side of the distributor plate, and an adjustment screw orthogonally connected to the bearing element, where the adjustment screw is externally accessible and manually rotatable to adjust a timing angle of the distributor plate. In a first example of the hydraulic axial piston assembly, the bearing element comprises a front surface, a back surface, and a circumferential outer surface and the adjustment screw comprises a coupling end, a longitudinal end, and a body positioned intermediate the coupling end and the longitudinal end. In a second example of the hydraulic axial piston assembly, optionally including the first example, the circumferential outer surface of the bearing element includes a top bore and the coupling end of the adjustment screw is positioned within the top bore. In a third example of the hydraulic axial piston assembly, optionally including one or both of the first and second examples, the hydraulic axial piston assembly further comprises: a distributor body, wherein the distributor body includes a front surface and a top surface that is orthogonal to the front surface. In a fourth example of the hydraulic axial piston assembly, optionally including one or more or each of the first through third examples, the distributor body includes a bearing element bore that extends through the front surface of the distributor body and the distributor body includes an adjustment screw bore that extends through the top surface of the distributor body and is orthogonal to the bearing element bore. In a fifth example of the hydraulic axial piston assembly, optionally including one or more or each of the first through fourth examples, the bearing element is positioned in the bearing element bore of the distributor body such that a circumferential outer surface of the bearing element is in face sharing contact with an inner surface of the bearing element bore. In a sixth example of the hydraulic axial piston assembly, optionally including one or more or each of the first through fifth examples, the adjustment screw is positioned in the adjustment screw bore of the distributor body such that the body of the adjustment screw is in face sharing contact with an inner surface of the adjustment screw bore. In a seventh example of the hydraulic axial piston assembly, optionally including one or more or each of the first through sixth examples, the adjustment screw bore is open to atmosphere and a longitudinal end of the adjustment screw includes a tool slot that is configured to accommodate a tool to rotate the adjustment screw. In an eighth example of the hydraulic axial piston assembly, optionally including one or more or each of the first through seventh examples, the distributor plate comprises a first flat surface, a second flat surface, and an outer circumferential surface. In a ninth example of the hydraulic axial piston assembly, optionally including one or more or each of the first through eighth examples, the distributor plate includes a central bore and a plurality of plate ports that extend through the first flat surface and the second flat surface. In a tenth example of the hydraulic axial piston assembly, optionally including one or more or each of the first through ninth examples, the front surface of the bearing element includes a front bore offset from a center of the front surface, and wherein a base of an eccentric pin is positioned within the front bore. In a eleventh example of the hydraulic axial piston assembly, optionally including one or more or each of the first through tenth examples, a head of the eccentric pin is coupled to the base of the eccentric pin and the head of the eccentric pin extends outwards past the front surface of the bearing element. In a twelfth example of the hydraulic axial piston assembly, optionally including one or more or each of the first through eleventh examples, the distributor plate includes a notch and an inner surface of the notch is in face sharing contact with a front surface, a bottom surface, a first side surface, and a second side surface of the head of the eccentric pin of the bearing element.
The disclosure also provides support for a hydraulic axial piston assembly, comprising: a distributor plate configured to fluidly couple one or more cylinder bores of an axial piston system to a distributor body that includes a fluid inlet passage and a fluid outlet passage, and an eccentric bearing including a pin housed within a notch of the distributor plate and configured to rotate via rotation of an adjustment screw, wherein the eccentric bearing and adjustment screw are positioned in the distributor body and wherein the adjustment screw extends orthogonally to the eccentric bearing. In a first example of the hydraulic axial piston assembly, the distributor plate fluidly couples the one or more cylinder bores of the axial piston system to the distributor body via a plurality of plate ports of the distributor plate, wherein a position of the plurality of plate ports is varied via rotation of the distributor plate. In a second example of the hydraulic axial piston assembly, optionally including the first example, the distributor body includes a plurality of body ports, wherein rotating the distributor plate changes the position of the plurality of plate ports of the distributor plate relative to a position of the plurality of body ports of the distributor body. In a third example of the hydraulic axial piston assembly, optionally including one or both of the first and second examples, rotation of the adjustment screw drives rotation of the eccentric bearing around an axis of rotation orthogonal to the axis of rotation of the adjustment screw.
The disclosure also provides support for a hydraulic axial piston assembly, comprising: an axial piston system, a distributor body coupled to the axial piston system via a coupling surface, the distributor body including a fluid inlet passage and a fluid outlet passage, the distributor body further including a first bore extending from an external surface of the distributor body to a second bore extending to the coupling surface of the distributor body, the first bore extending along a first axis that is orthogonal to a second axis along which the second bore extends, and a distributor plate configured to fluidly couple one or more cylinder bores of the axial piston system to the fluid inlet passage and the fluid outlet passage of the distributor body, wherein the distributor plate is rotatable via an eccentric bearing including a pin housed within a notch of the distributor plate and configured to rotate via rotation of an adjustment screw, wherein the eccentric bearing is housed in the second bore and adjustment screw is housed in the first bore. In a first example of the hydraulic axial piston assembly, the pin is positioned within the eccentric bearing such that the pin is offset from an axis of rotation of the eccentric bearing. In a second example of the hydraulic axial piston assembly, optionally including the first example, the adjustment screw includes a tool slot that is accessible from the external surface of the distributor body, wherein the tool slot is configured to accommodate a tool to rotate the adjustment screw.
As used herein, the term “approximately” is construed to mean plus or minus five percent of the range unless otherwise specified.
The following claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.