# US 2019/0376509 A1 · Variable displacement pump > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0376509 A1 - Document ID: US20190376509A1 - Status: Published application - Kind: A1 - Application number: 16/462,473 - Filed: 2017-10-27 - Published: 2019-12-12 - Earliest claimed: 2016-11-30 - Assignees: Hitachi Automotive Systems, Ltd. - Applicants: Hitachi Automotive Systems, Ltd. - Inventors: Shigeyuki MIYAZAWA - Web page: https://patentgrep.com/patent/US20190376509A1 ## CPC - F04C 2/344: with vanes reciprocating with respect to the inner member - F04C 2/3442: {the surfaces of the inner and outer member, forming the working space, being surfaces of revolution} - F04C 14/12: using sliding valves - F04C 14/226: {by pivoting the cam around an eccentric axis} - F04C 14/24: characterised by using valves controlling pressure or flow rate, e.g. discharge valves {or unloading valves}(F04C14/10 takes precedence) - F04C 28/12: using sliding valves - F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS ## Abstract A variable displacement pump according to the present invention is notably configured such that the opening area of a variable metering orifice (MO) is variably controlled by a second control valve (6) as a spool valve having a second spool valve body (61). According to this type of the second control valve (6), a larger amount of movement (stroke movement) of the second spool valve body (61) can be ensured. Consequently, the opening area of the variable metering orifice (MO) can be controlled without being restricted by a range of variation in a proper discharge amount based on an amount of movement of a cam ring (2), thereby achieving sufficient energy conservation of the pump. ## Claims ### Claim 1 A variable displacement pump, comprising: a pump housing including a pump element accommodation part thereinside; a cam ring formed in an annular shape and provided inside the pump element accommodation part; a pump element rotatably provided inside the cam ring and configured to carry out suction and discharge of hydraulic fluid; a first fluid pressure chamber and a second fluid pressure chamber that are a pair of spaces provided between the pump element accommodation part and the cam ring, wherein by acting a pressure of at least the first fluid pressure chamber on the cam ring, the cam ring is driven, and a proper discharge amount that is a discharge amount per one rotation of the pump element varies; a suction port provided to the pump housing and opened to a suction region of the pump element; a discharge port provided to the pump housing and opened to a discharge region of the pump element; a suction passage provided to the pump housing and used for supplying the hydraulic fluid to the suction port; a discharge passage provided to the pump housing and used for supplying the hydraulic fluid discharged from the discharge port to an outside of the pump housing; a variable metering orifice that is a throttle portion provided to the discharge passage; a first control valve that is a first control valve controlled based on a pressure on an upstream side and a pressure on a downstream side of the variable metering orifice, and which is configured to control a pressure to be introduced into the first fluid pressure chamber with the pressure on the upstream side of the metering orifice and a pressure of the suction passage; and a second control valve that is a second control valve configured to variably control an opening area of the variable metering orifice, and which is provided with a valve body controlled based on a pressure of the second fluid pressure chamber or the suction passage and a pressure of the first fluid pressure chamber. ### Claim 2 (depends on 1) The variable displacement pump according to claim 1, wherein the pressure of the suction passage is introduced into the second fluid pressure chamber. ### Claim 3 (depends on 1) The variable displacement pump according to claim 1, wherein the pressure on the downstream side of the variable metering orifice is introduced into the second fluid pressure chamber. ### Claim 4 (depends on 1) The variable displacement pump according to claim 1, wherein the second control valve is configured to increase the opening area of the variable metering orifice with a rise in the downstream pressure of the variable metering orifice. ### Claim 5 (depends on 4) The variable displacement pump according to claim 4, wherein the valve body is a spool valve body, and includes a first pressure receiving portion on which the pressure of the first fluid pressure chamber acts. ### Claim 6 (depends on 5) The variable displacement pump according to claim 5, wherein the spool valve body includes: a second pressure receiving portion for biasing the spool valve body in a direction in which the opening area of the variable metering orifice increases by acting the downstream pressure of the variable metering orifice thereon; and a third pressure receiving portion for biasing the spool valve body in a direction in which the opening area of the variable metering orifice decreases by acting the downstream pressure of the variable metering orifice thereon, the third pressure receiving portion having a smaller pressure receiving area than a pressure receiving area of the second pressure receiving portion. ### Claim 7 (depends on 5) The variable displacement pump according to claim 5, wherein the second control valve includes a thrust imparting mechanism for imparting thrust to the spool valve body in a direction in which the opening area of the variable metering orifice increases with a rise in the downstream pressure of the variable metering orifice. ### Claim 8 (depends on 1) The variable displacement pump according to claim 1, wherein the valve body is a spool valve body, and includes a first pressure receiving portion on which the pressure of the first fluid pressure chamber acts. ### Claim 9 (depends on 8) The variable displacement pump according to claim 8, wherein the second control valve includes: a first pressure chamber into which, through a first pressure introduction passage, the pressure of the first fluid pressure chamber is introduced; and a second pressure chamber into which, through a second pressure introduction passage, the pressure of the second fluid pressure chamber or the suction passage is introduced, and wherein a damper orifice that is a throttle portion is provided to the first pressure introduction passage or the second pressure introduction passage. ### Claim 10 (depends on 8) The variable displacement pump according to claim 8, wherein the second control valve includes: a first pressure chamber into which, through a first pressure introduction passage, the pressure of the first fluid pressure chamber is introduced; and a second pressure chamber into which, through a second pressure introduction passage, the pressure of the second fluid pressure chamber or the suction passage is introduced, and wherein a damper valve for buffering vibration of flow directed toward the first pressure chamber or the second pressure chamber is provided to the first pressure introduction passage or the second pressure introduction passage. ### Claim 11 (depends on 10) The variable displacement pump according to claim 10, wherein the damper valve is provided to the second pressure introduction passage. ### Claim 12 (depends on 8) The variable displacement pump according to claim 8, wherein the second control valve includes: a spool valve accommodation hole extending in a moving direction of the spool valve body; a discharge passage opening part provided to the spool valve accommodation hole and opened to the discharge passage; and a land part provided to the spool valve body and formed for varying the opening area of the discharge passage opening part with movement of the spool valve. ### Claim 13 (depends on 12) The variable displacement pump according to claim 12, wherein the discharge passage opening part has a circular shape in cross section. ### Claim 14 (depends on 1) The variable displacement pump according to claim 1, wherein the second control valve is provided separately from the pump housing.