Hydraulic actuators

• US 9,874,231 B2
• Filed: 01/14/2016
• Issued: 01/23/2018
• Est. Priority Date: 01/14/2015
• Status: Active Grant

• Current Assignee: BAE Systems Plc
• Original Assignee: BAE Systems Plc
• Inventors: Hare, Colin
• Primary Examiner(s): Leslie, Michael
• Assistant Examiner(s): Collins, Daniel
• Application Number:
  US14/995,391
• Publication Number:
  US 20160208824A1
• Time in Patent Office: 740 Days
• Field of Search: 60413
• CPC Class Codes: B64C 13/40 using fluid pressure
• CPC Class Codes: F15B 1/027 having accumulator charging devices
• CPC Class Codes: F15B 1/033 with electrical control means
• CPC Class Codes: F15B 1/08 using a gas cushion; Gas charging devices; Indicators or floats therefor
• CPC Class Codes: F15B 11/08 with only one servomotor
• CPC Class Codes: F15B 2201/00 Accumulators
• CPC Class Codes: F15B 2211/212 the pressure sources being accumulators
• CPC Class Codes: F15B 2211/625 Accumulators
• CPC Class Codes: F15B 2211/7053 Double-acting output members
• CPC Class Codes: F15B 2211/864 Failure of an output member, e.g. actuator or motor failure
• CPC Class Codes: F15B 2211/8752 Emergency operation mode, e.g. fail-safe operation mode
• CPC Class Codes: F15B 7/00 Systems in which the movement produced is definitely related to the output of a volumetric pump; Telemotors

Abstract

A hydraulic charging and driving system (4), aircraft employing the same, and corresponding methods, for extending and retracting a hydraulic actuator (2), comprising: a motor assembly (22); and an accumulator assembly (20), the motor assembly (22) and the accumulator assembly (20) being hydraulically coupled to each other; wherein the motor assembly (22) is arranged to recharge the accumulator assembly (20) with hydraulic fluid at a relatively slow rate that is slower than the rate at which the accumulator assembly (20) is arranged to discharge when actuating the hydraulic actuator (2). The system may further comprise a selector valve (24). The accumulator assembly (20) may comprise an accumulator chamber (30), and a compression means (32) provided within the accumulator chamber (30). The motor assembly (22) may comprise a motor (42) arranged to vary a volume of a hydraulic charging chamber (38) of the motor assembly (22).

Claims

1. A hydraulic charging and driving system (4) for extending and retracting a hydraulic actuator (2), comprising:

a motor assembly (22), the motor assembly (22) comprising a motor (42), a piston (36) and a charging chamber (38);

an accumulator assembly (20) comprising an accumulator chamber (30);

the charging chamber (38) and the accumulator chamber (30) being hydraulically coupled to each other; and

a selector valve (24);

wherein

the motor assembly (22) is arranged to recharge the accumulator assembly (20) with hydraulic fluid by the motor (42) moving the piston (36) to eject the hydraulic fluid from the charging chamber (38) of the motor assembly (22) into the accumulator chamber (30) of the accumulator assembly (20);

the accumulator assembly (20) and the selector valve (24) are arranged such that hydraulic fluid in the accumulator chamber (30) discharges via the selector valve (24) into the hydraulic actuator (2) to provide at least a part of an actuation of the hydraulic actuator (2) responsive to the selector valve (24) being switched; and

the recharging of the accumulator assembly (20) is performed at a relatively slow rate that is slower than the rate at which the accumulator assembly (20) is arranged to discharge when providing the at least part of the actuation of the hydraulic actuator (2).

2. The system according to claim 1, wherein the accumulator assembly (20) comprises a compression means (32) provided within the accumulator chamber (30).

3. A system according to claim 1, further comprising a hydraulic actuator (2) comprising a bottom chamber (16) and a piston-side chamber (18);

wherein the accumulator assembly (20) is hydraulically coupled to the bottom chamber (16) via a first setting of the selector valve (24) to provide extension of the hydraulic actuator (2).

4. A system according to claim 3, wherein the accumulator assembly (20) is further hydraulically coupled to the piston-side chamber (18), in addition to being hydraulically coupled to the bottom chamber (16), via the first setting of the selector valve (24) to provide extension of the hydraulic actuator (2).

5. A system according to claim 3, wherein the piston-side chamber (18) is hydraulically coupled to the motor assembly (22) via a further setting of the selector valve (24) to provide retraction of the hydraulic actuator (2).

6. A system according to claim 1, wherein the whole of the actuation of the hydraulic actuator (2) is provided by the discharge of the hydraulic fluid from the accumulator chamber (30) via the selector valve (24) to the hydraulic actuator (2).

7. A system according to claim 1, further comprising an emergency assembly (26) arranged to provide at least emergency extension of the hydraulic actuator (2).

8. An aircraft comprising a plurality of separate hydraulic charging and driving systems according to claim 1, each of the systems providing independent operation to a respective different movable part of the aircraft.

9. A method of operating a hydraulic system comprising a hydraulic actuator (2), a selector valve (24), a motor assembly (22), and an accumulator assembly (20) hydraulically coupled in a hydraulic circuit (28), the motor assembly (22) comprising a motor (42), a piston (36) and a charging chamber (38), the accumulator assembly (20) comprising an accumulator chamber (30), the charging chamber (38) and the accumulator chamber (30) being hydraulically coupled to each other via a part of the hydraulic circuit (28);

the method comprising;

hydraulically extending the hydraulic actuator (2), the hydraulic extension being provided at least in part by hydraulic fluid being discharged from the accumulator chamber (30) via the selector valve (24) to the hydraulic actuator (2) responsive to the selector valve (24) being switched; and

thereafter, recharging the accumulator assembly (20) with hydraulic fluid at a relatively slow recharge rate such that the recharge takes longer than the time taken to extend the hydraulic actuator (2), the recharging being performed by the motor (42) moving the piston (36) to eject hydraulic fluid from the charging chamber (38) of the motor assembly (22) into the accumulator chamber (30) of the accumulator assembly (20).

10. A method according to claim 9, wherein the step of hydraulically extending the hydraulic actuator (2) is performed by hydraulically coupling the accumulator assembly (20) to a bottom chamber (16) of the hydraulic actuator (2) by setting the selector valve (24) to a first setting.

11. A method according to claim 10, wherein the step of hydraulically extending the hydraulic actuator (2) is performed by, in addition to hydraulically coupling the accumulator assembly (20) to a bottom chamber (16) of the hydraulic actuator (2), also hydraulically coupling the accumulator assembly (20) to the piston-side chamber (18), by setting the selector valve (24) to the first setting.

12. A method according to claim 9, the method further comprising hydraulically retracting the hydraulic actuator (2).

13. A method according to claim 12, the method further comprising, after hydraulically retracting the hydraulic actuator (2), recharging the accumulator assembly (20) with hydraulic fluid via the hydraulic circuit (28) at a relatively slow recharge rate such that the recharge takes longer than the time taken to retract the hydraulic actuator (2).

14. A method according to claim 9, the method further comprising performing at least an emergency extension of the hydraulic actuator (2).

15. A method of operating an aircraft, comprising operating a first moveable part of the aircraft by implementing the method of claim 9 using a first hydraulic system, and operating a second moveable part of the aircraft of the aircraft by implementing the method of claim 9 using a second hydraulic system, the first and second hydraulic systems being two respective closed hydraulic systems.