Valve plate arrangement for an axial piston pump

Patent metadata

Field	Value
Publication number	US-9803634-B2
Application number	US-201414478180-A
Country	US
Kind code	B2
Filing date	Sep 5, 2014
Priority date	Sep 5, 2014
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

An axial piston pump may comprise a valve plate assembly including a plurality of valve plates rotatably disposed adjacent to each other and configured to control the flow of fluid between a piston chamber and inlet and outlet port passages. The piston pump may also comprise a swashplate arrangement that is capable of being angled in two different directions to be used in combination with the valve plate assembly. A fixed displacement axial piston pump may also comprise the valve plate assembly disclosed herein in which pressure transitions are facilitated in the same fashion, but without the variable of changing swashplate angles which control pump flow.

First claim

I claim:

1. A variable displacement axial piston pump adapted for use in a fluid system, comprising:
a housing having a body portion and a head portion with an inlet port passage and an outlet port passage;
a rotating group disposed in the body portion and having an axis of rotation and including:
a barrel having a plurality of cylinder bores,
a plurality of piston assemblies with each of the plurality of piston assemblies having a piston slideably disposed within one of the cylinder bores, and
a shoe pivotably attached to and extending from the piston, the rotating group being in fluid communication with the inlet and outlet port passages of the head portion;

a valve plate assembly disposed between the head portion of the housing and the rotating group, the valve plate assembly comprising:
a plurality of plates rotatably disposed adjacent each other and configured to control a flow of fluid between the rotating group and one or more of the inlet and outlet port passages of the head portion,
wherein one or more of the plurality of plates comprises an arcuate slot configured to control the flow of fluid between the rotating group and one or more of the inlet and outlet port passages of the housing head portion, and the one or more plurality of plates comprise a first plate comprising a first arcuate slot, and a second plate comprising a second arcuate slot;

a swashplate arrangement disposed in the body portion and being pivotable in a first arcuate direction relative to the axis of rotation of the rotating group and pivotable in a second arcuate direction relative to the axis of rotation of the rotating group; and
a protrusion disposed adjacent the first arcuate slot of the first plate, the protrusion configured to nest with at least a portion of the second arcuate slot of the second plate.

2. The variable displacement axial piston pump of claim 1 , in combination with a fluid system having a tank, fluid actuator, and a fluid control valve disposed between the fluid actuator and the variable displacement axial piston pump.

3. The variable displacement axial piston pump of claim 1 , wherein each of the plurality of plates comprises an arcuate slot configured to control a flow of fluid between the rotating group and one or more of the inlet and outlet port passages of the head portion.

4. The variable displacement axial piston pump of claim 1 , wherein an alignment of each of the arcuate slots of the plurality of plates relative to each other defines the flow of fluid between the rotating group and one or more of the inlet and outlet port passages of the housing head portion.

5. The variable displacement axial piston pump of claim 1 , wherein the swashplate arrangement comprises a primary member disposed in the body portion and pivotable in the first arcuate direction relative to the axis of rotation of the rotating group and a secondary member disposed within the primary member that pivots in the second arcuate direction relative to the primary member.

6. The variable displacement axial piston pump of claim 5 , wherein the pivot direction of the primary member is at an angle about the axis of rotation of the rotating group with respect to the pivot direction of the secondary member.

7. The variable displacement axial piston pump of claim 5 , including an actuating mechanism disposed between the primary member and the secondary member.

8. A method of operating an axial piston pump comprising a swashplate, a valve plate assembly comprising a plurality of plates, and a group of piston assemblies disposed between the swashplate and the valve plate assembly, the method comprising:
adjusting a position of a swashplate arrangement in at least one direction to displace one or more of a top dead center and a bottom dead center of the group of piston assemblies;
slideably rotating one or more of the plurality of plates of the valve plate assembly relative to another plate of the plurality of plates to control the compression or decompression of an amount of trapped fluid volume effected by the valve plate assembly; and
rotating the group of piston assemblies,
wherein one or more of the plurality of plates comprises:
an arcuate slot configured to control a flow of fluid between the group of piston assemblies and one or more of the inlet port passage and the outlet port passage, and
a protrusion disposed adjacent the arcuate slot and configured to nest with at least a portion of an arcuate slot of another one of the plurality of plates.

Assignees

• Caterpillar Inc

Inventors

• May Michael P

Classifications

• F04B53/10

  Valves; Arrangement of valves · CPC title

• F16K3/029

  with two or more gates · CPC title

• F16K3/316

  Guiding of the slide · CPC title

• F04B49/225 Primary

  with throttling valves or valves varying the pump inlet opening or the outlet opening · CPC title

• F04B1/2042

  Valves · CPC title