Hydraulic radial piston device with improved pressure transition mechanism

Patent metadata

Field	Value
Publication number	US-10378357-B2
Application number	US-201614995904-A
Country	US
Kind code	B2
Filing date	Jan 14, 2016
Priority date	Jan 20, 2015
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

A hydraulic radial piston device is provided with a mechanism for reducing pressure pulsations and providing a smooth pressure transition throughout different displacement operations. In certain examples, the hydraulic radial piston device is configured to maintain an amount of precompression and an amount of decompression of hydraulic fluid trapped in a cylinder chamber to be consistent, respectively, throughout different displacement operations.

First claim

What is claimed is:

1. A hydraulic radial piston device comprising:
a housing having a hydraulic fluid inlet and a hydraulic fluid outlet;
a pintle shaft fixed within the housing, the pintle shaft defining a pintle inlet and a pintle outlet, the pintle inlet being in fluid communication with the hydraulic fluid inlet, and the pintle outlet being in fluid communication with the hydraulic fluid outlet;
a rotor mounted on the pintle shaft and configured to rotate relative to the pintle shaft about a rotor axis of rotation, the rotor axis of rotation extending through a length of the pintle shaft, the rotor defining a plurality of radially oriented cylinders and a plurality of rotor fluid ports, each of the plurality of rotor fluid ports being in fluid communication with at least one of the plurality of radially oriented cylinders and being alternatively in fluid communication with either the pintle inlet or the pintle outlet as the rotor rotates relative to the pintle shaft about the rotor axis of rotation;
a plurality of pistons received in the plurality of radially oriented cylinders, respectively;
a thrust ring disposed about the rotor and having a thrust ring axis of rotation, the thrust ring being in contact with the plurality of pistons and configured to rotate about the thrust ring axis of rotation as the rotor rotates relative to the pintle shaft about the rotor axis of rotation; and
a ring displacement driver operable to move the thrust ring through a range of movement within the housing between a first position in which the radial piston device has a minimum displacement of hydraulic fluid per each rotation of the rotor and a second position in which the radial piston device has a maximum displacement of hydraulic fluid per each rotation of the rotor, the ring displacement driver operating to maintain the thrust ring axis of rotation in offset relation relative to the rotor axis of rotation such that a precompression stroke distance and a decompression stroke distance of each of the plurality of pistons remain consistent, respectively, regardless of a position of the thrust ring in the range of movement of the thrust ring within the housing, thereby providing a smooth pressure transition in the each of the plurality of radially oriented cylinders.

2. The hydraulic radial piston device according to claim 1 , wherein the pintle inlet and the pintle outlet are spaced apart 180 degrees around the pintle shaft to define a first reference line extending through the pintle inlet and the pintle outlet and intersecting the rotor axis of rotation.

3. The hydraulic radial piston device according to claim 2 , further comprising an offset reference line extending through the rotor axis of rotation and the thrust ring axis of rotation, the offset reference line being aligned with the first reference line when the thrust ring is in the first position.

4. The hydraulic radial piston device according to claim 3 , wherein the offset reference line that intersects the rotor axis of rotation and the thrust ring axis of rotation rotates about the rotor axis of rotation as the thrust ring is moved through the range of movement.

5. The hydraulic radial piston device according to claim 1 , wherein:
the pintle shaft has an outer circumferential surface defining a fluid inlet section, a fluid precompression section, a fluid outlet section, and a fluid decompression section, the fluid inlet section defined by the pintle inlet, the fluid outlet section defined by the pintle outlet, the precompression section defined as a region between the fluid inlet section and the fluid outlet section, and the decompression section defined as a region between the fluid outlet section and the fluid inlet section and opposite to the precompression section;
each of the plurality of rotor fluid ports moves on the outer circumferential surface of the pintle shaft to pass the fluid inlet section, the fluid precompression section, the fluid outlet section, and the fluid decompression section as the rotor rotates relative to the pintle shaft about the rotor axis of rotation;
the fluid inlet section and the fluid outlet section are arranged to be oppositely positioned about the rotor axis of rotation to define a first reference line extending through the fluid inlet section and the fluid outlet section and intersecting the rotor axis of rotation; and
the precompression section and the decompression section are arranged to be oppositely positioned about the rotor axis of rotation to define a second reference line extending through the precompression section and the decompression section and intersecting the rotor axis of rotation.

6. The hydraulic radial piston device according to claim 5 , wherein the first reference line is perpendicular to the second reference line.

7. The hydraulic radial piston device according to claim 5 , further comprising an offset reference line extending through the rotor axis of rotation and the thrust ring axis of rotation, the offset reference line being aligned with the first reference line when the thrust ring is in the first position and with the second reference line when the thrust ring is in the second position.

8. The hydraulic radial piston device according to claim 7 , wherein the ring displacement driver is configured to adjust a position of the thrust ring within the housing between the first and second positions such that the offset reference line pivots about the rotor axis of rotation as the thrust ring is moved through the range of movement, wherein a decompression value that occurs within the cylinders as the rotor fluid ports move across the decompression section remains constant as the thrust ring moves through the range of movement, and wherein a compression value that occurs within the cylinders as the rotor fluid ports move across the precompression section remains constant as the thrust ring moves through the range of movement.

9. The hydraulic radial piston device according to claim 1 , wherein the ring displacement driver comprises a cam ring configured to at least partially receive and rotatably support the thrust ring, and a control element engageable with the cam ring and operable to adjust a position of the cam ring within the housing.

10. The hydraulic radial piston device according to claim 9 , wherein:
the housing includes an inner cam supporting surface; and
the control element is configured to move the cam ring along the inner cam supporting surface such that the thrust ring axis of rotation moves in parallel with the inner cam supporting surface while being offset from the rotor axis of rotation.

11. The hydraulic radial piston device according to claim 10 , wherein the inner cam supporting surface of the housing is tilted to define a ramp surface on which the cam ring moves such that the thrust ring axis of rotation moves in parallel with the ramp surface while being offset from the rotor axis of rotation.

12. A hydraulic radial piston device comprising:
a housing having a hydraulic fluid inlet and a hydraulic fluid outlet;
a pintle shaft fixed within the housing, the pintle shaft having an outer circumferential surface defining a fluid inlet section, a fluid precompression section, a fluid outlet section, and a fluid decompression section, the pintle shaft including a pintle inlet defined in the fluid inlet section and a pintle outlet defined in the fluid outlet section, the pintle inlet being in fluid communication with the hydraulic fluid inlet, and the pintle outlet being in fluid communication with the hydraulic fluid outlet;
a rotor mounted on the pintle shaft and configured to rotate relative to the pintle shaft about a rotor axis of rotation, the ro

Assignees

• Eaton Intelligent Power Ltd

Inventors

• Skinner Jeffrey David
• Gibson Kendrick Michael
• Blackman Lawrence David

Classifications

• F01B1/061

  with two or more series radial piston-cylinder units · CPC title

• F04B1/047

  with actuating or actuated elements at the outer ends of the cylinders · CPC title

• F03C1/047

  the pistons co-operating with an actuated element at the outer ends of the cylinders · CPC title

• F04B1/07 Primary

  by varying the relative eccentricity between two members, e.g. a cam and a drive shaft · CPC title

• F03C1/046

  by changing the excentricity of one element relative to another element · CPC title