US 12,448,955 B2
Displacement control for hydraulic pump
Matthew H. Simon, Paw Paw, MI (US); Daniel Dyminski, Portage, MI (US); and Brewce Larkin, Everett, WA (US)
Assigned to Parker-Hannifin Corporation, Cleveland, OH (US)
Appl. No. 18/255,795
Filed by Parker-Hannifin Corporation, Cleveland, OH (US)
PCT Filed Feb. 14, 2022, PCT No. PCT/US2022/016262
§ 371(c)(1), (2) Date Jun. 2, 2023,
PCT Pub. No. WO2022/177841, PCT Pub. Date Aug. 25, 2022.
Claims priority of provisional application 63/149,833, filed on Feb. 16, 2021.
Prior Publication US 2024/0003341 A1, Jan. 4, 2024
Int. Cl. F04B 1/324 (2020.01); F04B 1/20 (2020.01); F04B 1/2078 (2020.01); F04B 49/00 (2006.01)
CPC F04B 1/324 (2013.01) [F04B 1/20 (2013.01); F04B 49/002 (2013.01); F04B 1/2078 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A hydraulic pump comprising:
a piston rotating group comprising a plurality of reciprocating pistons configured to displace a volume of hydraulic fluid from the pump;
a movable displacement control member that is configured to move within a displacement range to interact with the pistons and vary the displacement of the pump;
a control actuator configured to interact with the movable displacement control member to control the position of the displacement control member within the displacement range; and
a displacement control valve assembly configured to provide mechanical feedback control of the position of the control actuator and thereby the displacement control member;
wherein the displacement control valve assembly includes a control valve member that is movable within a fluid flow path of the displacement control valve assembly to control a flow of fluid to or from the control actuator, the control valve member including a first valve part, a second valve part, and a biasing member configured to selectively position one or more portions of the first valve part and one or more portions of the second valve part relative to each other to open or close a vent flow passage in response to an operating state of the pump;
wherein in a normal operating state of the pump, the biasing member is configured to position the one or more portions of the first valve part and the one or more portions of the second valve part relative to each other such that the vent flow passage is closed, and the control valve member is movable in the fluid flow path to control the flow of fluid to or from the control actuator;
wherein in a failsafe state of the pump, the biasing member is configured to position the one or more portions of the first valve part and the one or more portions of the second valve part relative to each other such that the vent flow passage is opened, thereby enabling fluid from the control actuator to escape via the vent flow passage;
wherein the first and second valve parts are discrete parts, and at least in the normal operating state, the first valve part and the second valve part are rigidly-coupled together for common axial movement;
wherein the second valve part is configured as a check valve member, wherein the second valve part separates from the first valve part to open a flow path between the first and second valve parts,
wherein the second valve part includes a main body portion and an intermediate portion movable relative to the main body portion;
wherein the biasing member is interposed between the main body portion and the intermediate portion; and
wherein the first valve part maintains engagement with the intermediate portion of the second valve part for common axial movement therewith relative to the main body portion.