Variable displacement pumps

Patent metadata

Field	Value
Publication number	US-2024183345-A1
Application number	US-202218075199-A
Country	US
Kind code	A1
Filing date	Dec 5, 2022
Priority date	Dec 5, 2022
Publication date	Jun 6, 2024
Grant date	—

Abstract

A variable displacement pump system can include a piston sleeve having at least a first inner diameter portion and a second in inner diameter portion and an actuator piston configured to be disposed within the piston sleeve. The actuator piston can have a first piston portion having a first outer diameter, and a second piston portion having a second outer diameter. The first outer diameter can be different than the second outer diameter. The first piston portion can be configured to seal to the first inner diameter portion of the piston sleeve. The second piston portion of the actuator piston can be configured to seal to the second inner diameter portion of the piston sleeve.

First claim

What is claimed is:

1 . A variable displacement pump system, comprising:
a piston sleeve having at least a first inner diameter portion and a second inner diameter portion; an actuator piston configured to be disposed within the piston sleeve, the actuator piston having:
a first piston portion having a first outer diameter; and
a second piston portion having a second outer diameter, wherein the first outer diameter is different than the second outer diameter, wherein the first piston portion is configured to seal to the first inner diameter portion of the piston sleeve, and wherein the second piston portion of the actuator piston is configured to seal to the second inner diameter portion of the piston sleeve.

2 . The variable displacement pump system of claim 1 , wherein the first piston portion of the actuator piston and the first inner diameter portion of the piston sleeve define a first pressure volume, wherein the first piston portion and second piston portion of the actuator piston and the first inner diameter portion and the second inner diameter portion of the piston sleeve define a second pressure volume.

3 . The variable displacement pump system of claim 2 , wherein the piston sleeve includes a first port in fluid communication with the first pressure volume and a second port in fluid communication with the second pressure volume.

4 . The variable displacement system of claim 1 , wherein the first outer diameter is smaller than the second outer diameter.

5 . The variable displacement pump system of claim 1 , further comprising an actuator rod operatively connected to the second piston portion of the actuator piston via a ball joint, wherein the actuator rod is configured to connect to a tilting mechanism of a variable displacement pump, wherein a rod connection side of the second piston portion of the actuator piston is configured to be exposed to a pump inlet pressure.

6 . The variable displacement pump of claim 1 , wherein the actuator is top-hat shaped.

7 . The variable displacement system of claim 1 , wherein the piston sleeve has a third inner diameter portion different than the second inner diameter, wherein the actuator piston further includes a third piston portion having a third outer diameter, wherein the third piston portion is configured to seal to the third inner diameter portion of the piston sleeve.

8 . The variable displacement system of claim 7 , wherein the third inner diameter portion is smaller than the second inner diameter portion, wherein the third outer diameter is smaller than the first outer diameter

9 . The variable displacement system of claim 8 , wherein the third inner diameter portion is the same diameter as the first inner diameter portion, wherein the third outer diameter is the same as the first outer diameter.

10 . The variable displacement system of claim 7 , wherein the first piston portion of the actuator piston and the first inner diameter portion of the piston sleeve define a first pressure volume, wherein the first piston portion and second piston portion of the actuator piston and the first inner diameter portion and the second inner diameter portion of the piston sleeve define a second pressure volume, and wherein the third piston portion and second piston portion of the actuator piston and the third inner diameter portion of the piston sleeve define a third pressure volume.

11 . The variable displacement pump system of claim 10 , wherein the piston sleeve includes a first port in fluid communication with the first pressure volume and a second port in fluid communication with the second pressure volume, wherein the piston sleeve includes a third port in fluid communication with the third pressure volume.

12 . The variable displacement system of claim 11 , wherein the actuator rod is operatively connected to the third piston portion of the actuator via a ball joint, wherein a rod connection side of the third piston portion of the actuator piston is configured to be exposed to a pump inlet pressure.

13 . The variable displacement pump of claim 10 , wherein the third inner diameter portion forms a standoff to limit a position of the actuator piston.

14 . The variable displacement pump system of claim 1 , wherein the actuator piston includes a plurality of glands defined therein and configured to receive one or more seals, wherein the plurality of glands include at least one gland defined on each portion of the actuator piston.

15 . The variable displacement pump system of claim 3 , further comprising an electro-hydraulic servo valve (EHSV) configured to provide controlled pressure to one or more of the ports.

16 . The variable displacement pump system of claim 15 , wherein the EHSV is operatively connected to the first port to provide a first controlled pressure to the first port and operatively connected to the second port to provide a second controlled pressure to the second port.

17 . The variable displacement pump system of claim 15 , wherein the EHSV is operatively connected to the second port to provide a controlled pressure to the second port, wherein the first port is configured to be connected to a pump discharge pressure.

18 . An actuator piston assembly for a variable displacement pump, comprising:
an actuator piston; and a piston sleeve, wherein the actuator piston and the piston sleeve are configured to define at least a first pressure volume and a second pressure volume therebetween, wherein the first pressure volume is in fluid communication with a first pressure port and wherein the second pressure volume is in fluid communication with a second pressure port such that a position and/or rate of movement of the actuator piston within the piston sleeve is controllable as a function of a first pressure applied to the first pressure port and a second pressure applied to the second pressure port.

19 . A non-transitory computer readable medium, comprising computer executable instructions configured to cause a computer to perform a method, the method, comprising:
controlling a pressure provided to a plurality of ports of an actuator piston assembly of a variable displacement pump to control a slew rate of an actuator piston.

20 . The non-transitory computer readable medium of claim 19 , wherein controlling the pressure includes controlling an electrohydraulic servo valve (EHSV) connected to at least one of the plurality of ports.

Assignees

• Hamilton Sundstrand Corp

Inventors

• Goy Edward W
• Le Duc Zachary Allen Ray
• Shoemaker Mark W
• Rosenberg Mason

Classifications

• F04B9/02 Primary

  the means being mechanical · CPC title

• F04B19/22

  of reciprocating-piston type · CPC title

• F04B53/14

  Pistons, piston-rods or piston-rod connections · CPC title

• F04B53/144

  Adaptation of piston-rods · CPC title

• F04B1/146 Primary

  Swash plates; Actuating elements · CPC title