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WO-2026094903-A1 - CLOSED LIQUID SYSTEM

WO2026094903A1WO 2026094903 A1WO2026094903 A1WO 2026094903A1WO-2026094903-A1

Abstract

A closed liquid system (1) comprises: a positive displacement pump (7) that is connected to objects (21 to 26) via a supply path (41) and supplies liquid to the objects; a reservoir (6) that is connected to the objects via a return path (42) and pressurizes liquid stored therein; and a booster device (8) that is located in a second supply path (43) connecting the positive displacement pump and the reservoir, and has a non-positive displacement pump that boosts the pressure of the pressurized liquid from the reservoir and sends the boosted liquid to the positive displacement pump.

Inventors

  • HASEGAWA KAZUOMI
  • ONISHI TAKAAKI
  • MINAMI YUTARO

Assignees

  • 住友精密工業株式会社

Dates

Publication Date
20260507
Application Date
20251028
Priority Date
20241029

Claims (18)

  1. A positive displacement pump connected to an object via a supply path and supplying liquid to the object, A reservoir connected to the object via a return path, comprising a reservoir that pressurizes the liquid stored therein, A boosting device having a non-positive displacement pump located in a second supply path connecting the positive displacement pump and the reservoir, and which boosts the pressurized liquid from the reservoir and sends it to the positive displacement pump, A closed liquid system equipped with [a specific feature/feature].
  2. In the closed liquid system according to claim 1, A closed liquid system comprising a bypass path that bypasses the boosting device and connects the reservoir and the positive displacement pump, further comprising an openable and closable bypass path.
  3. In the closed liquid system according to claim 2, The bypass path is a closed liquid system that is opened and closed depending on the state of the closed liquid system.
  4. In the closed liquid system according to claim 3, The bypass path is a closed liquid system that opens and closes in accordance with the difference between the discharge pressure of the booster device and the pressure of the reservoir.
  5. In the closed liquid system according to claim 4, A closed liquid system located in the bypass path and further comprising a check valve that prevents backflow from the second supply path to the reservoir.
  6. In the closed liquid system according to claim 4, A closed liquid system further comprising a switching valve that, when the difference between the discharge pressure of the boosting device and the pressure of the reservoir exceeds a predetermined value, opens the bypass passage and closes the second supply passage, and when the difference between the discharge pressure of the boosting device and the pressure of the reservoir falls below the predetermined value, closes the bypass passage and opens the second supply passage.
  7. In the closed liquid system according to claim 3, The bypass is a closed fluid system that opens and closes in accordance with the pressure of the reservoir.
  8. In the closed liquid system according to claim 2, A closed liquid system in which the opening of the bypass path changes according to the state of the closed liquid system.
  9. In a closed liquid system according to any one of claims 1 to 8, The positive displacement pump, the reservoir, the boosting device, the supply path, the return path, and the second supply path constitute a closed liquid system, forming a closed circulation circuit isolated from the outside.
  10. In a closed liquid system according to any one of claims 1 to 9, The reservoir is a closed liquid system having a storage chamber and a pressure accumulator, and pressurizing the liquid in the storage chamber by the pressure of the gas filled in the pressure accumulator.
  11. In a closed liquid system according to any one of claims 1 to 10, The boosting device is a closed liquid system having one or more of the non-positive displacement pumps.
  12. In the closed liquid system according to claim 11, The boosting device is a closed liquid system having at least one of a centrifugal pump and an inducer.
  13. In the closed liquid system according to claim 12, The boosting device is a closed liquid system having the centrifugal pump and the inducer provided at the suction portion of the centrifugal pump.
  14. In a closed liquid system according to any one of claims 1 to 10, The boosting device is a closed liquid system having a centrifugal pump and a diffuser provided at the discharge section of the centrifugal pump.
  15. In a closed liquid system according to any one of claims 1 to 10, The pressure boosting device is a closed liquid system comprising a centrifugal pump, an inducer provided at the suction portion of the centrifugal pump, and a diffuser provided at the discharge portion of the centrifugal pump.
  16. In a closed liquid system according to any one of claims 1 to 15, A closed liquid system further comprising a prime mover connected to both the positive displacement pump and the booster device, and for driving each of the positive displacement pump and the booster device, respectively.
  17. In a closed liquid system according to any one of claims 1 to 16, A closed-loop liquid system installed on an aircraft.
  18. In the closed liquid system according to claim 17, The object includes at least one of the aircraft's flight control actuator and its takeoff and landing actuator, The positive displacement pump is a closed liquid system that supplies hydraulic fluid to the actuator to power the actuator.

Description

Closed liquid system The technology disclosed herein relates to a closed liquid system. Patent Document 1 describes a conventional EHA (Electro-Hydraulic Actuator) system. The EHA system is an example of a closed-loop fluid system. The EHA system described in Patent Document 1 is mounted on an aircraft. The EHA system raises and lowers the landing gear. The EHA system comprises a hydraulic actuator and an electric hydraulic pump. The hydraulic actuator is attached to the aircraft's landing gear and raises and lowers the gear. The electric hydraulic pump is connected to the hydraulic actuator via a supply channel and supplies hydraulic fluid to the hydraulic actuator. The EHA system further comprises a reservoir. The reservoir is a tank for absorbing the volume fluctuations within the hydraulic actuator due to its extension and retraction. The reservoir is connected to the electric hydraulic pump via a supply channel and to the hydraulic actuator via a return channel. Figure 1 shows an aircraft-mounted hydraulic system as a closed fluid system.Figure 2 shows various configurations of a boost device.Figure 3 shows the change in hydraulic fluid pressure from the reservoir to the pump.Figure 4 shows a part of the liquid system related to the modified example; the upper figure shows the supply state of hydraulic fluid through the booster device, and the lower figure shows the supply state of hydraulic fluid through the bypass path.Figure 5 shows the operation of the switching valve in a modified example.Figure 6 shows a part of the modified liquid system; the upper figure shows the supply state of hydraulic fluid through the booster device, and the lower figure shows the supply state of hydraulic fluid through the bypass.Figure 7 shows a part of the modified liquid system; the upper figure shows the supply state of hydraulic fluid through the booster device, and the lower figure shows the supply state of hydraulic fluid through the bypass. The following describes embodiments of a closed liquid system with reference to the drawings. The closed liquid system described here is illustrative. (Overall configuration of a closed liquid system) Figure 1 shows the overall configuration of the closed-loop fluid system 1. The closed-loop fluid system 1 is installed on an aircraft. The closed-loop fluid system 1 supplies hydraulic fluid to the hydraulic equipment installed on the aircraft. The closed-loop fluid system 1 is the aircraft's hydraulic system. The closed-loop fluid system 1 comprises a hydraulic circuit 10 including multiple hydraulic devices. The hydraulic equipment includes, as an example, the following hydraulic actuators 21-26. Specifically, as shown in Figure 1, the hydraulic equipment includes an aileron actuator 21, an elevator actuator 22, a rudder actuator 23, a flap actuator 24, a slat actuator 25, and a landing gear actuator 26. The landing gear actuator 26 includes, for example, at least one of the following actuators: a gear actuator, a door actuator, and a downlock release actuator. The gear actuator is an actuator that raises and lowers the landing gear struts. The door actuator is an actuator that opens and closes the doors of the bay that houses the landing gear. The downlock release actuator is an actuator that releases the downlock mechanism that fixes the landing gear struts in the lowered position. These hydraulic actuators 21-26 are examples of objects to which the closed liquid system 1 supplies hydraulic fluid. Hydraulic fluid is an example of a liquid. The closed liquid system 1 may supply hydraulic fluid to a portion of the hydraulic actuators 21-26. The closed liquid system 1 may also supply hydraulic fluid to hydraulic equipment other than the hydraulic actuators 21-26. The hydraulic actuators 21-26 are, for example, telescopic actuators having a cylinder and a piston. The aileron actuator 21, elevator actuator 22, and rudder actuator 23 are primary flight control actuators that operate during the aircraft's cruising flight and during takeoff and landing. Primary flight control actuators have a relatively short stroke and operate intermittently over long periods during aircraft flight. The pressure required for the operation of primary flight control actuators is relatively high. Furthermore, the flow rate of hydraulic fluid required for the operation of primary flight control actuators is relatively low. The flap actuator 24 and the slat actuator 25 are secondary flight control actuators. Both the flap actuator 24 and the slat actuator 25 are included in the category of flight control actuators. The flap actuator 24 and the slat actuator 25 have a moderate stroke and operate temporarily during aircraft takeoff and landing. The pressure required for the operation of the secondary flight control actuators is moderate. Furthermore, the hydraulic fluid flow rate required for the operation of the secondary flight control actuators is also moderate. Hereinafter, the aileron actuator 21, el