Fail-fixed hydraulic actuator

Patent metadata

Field	Value
Publication number	US-10619654-B2
Application number	US-201715588162-A
Country	US
Kind code	B2
Filing date	May 5, 2017
Priority date	May 5, 2017
Publication date	Apr 14, 2020
Grant date	Apr 14, 2020

Abstract

A method of operating a fail-fixed hydraulic actuator system is provided. The method includes providing an actuator in an initial position, electromechanically operating a valve assembly to hydraulically drive actuator movement and halting the hydraulic driving of the actuator movement by the valve assembly.

First claim

What is claimed is:

1. A method of operating a fail-fixed hydraulic actuator system, the method comprising:
providing an actuator in an initial position;
electromechanically operating a valve assembly to hydraulically drive actuator movement relative to the initial position; and
halting the hydraulic driving of the actuator movement by the valve assembly,
wherein:
the actuator comprises:
a ramp toward which a lever configured to execute the halting is elastically biased;
a body defining cavities on opposite sides of the ramp; and
piping fluidly communicative with the cavities, and

the valve assembly increases pressure in the cavities via the piping to hydraulically drive the actuator movement.

2. The method according to claim 1 , further comprising executing the electromechanically operating in accordance with the actuator movement.

3. The method according to claim 1 , wherein the electromechanical operation comprises controlling a cam with a stepper motor to assume various angular positions.

4. The method according to claim 1 , further comprising communicating high and low pressure fluids from an engine system between the cavities of the actuator and the valve assembly via the piping to hydraulically drive the actuator.

5. A fail-fixed hydraulic actuator system, comprising:
an actuator disposable in an initial position;
a valve assembly configured to hydraulically drive actuator movement relative to the initial position;
a stepper motor assembly that initiates an hydraulic driving of the actuator movement by electromechanical operation of the valve assembly; and
a lever that halts the hydraulic driving of the actuator movement by the valve assembly,
wherein:
the actuator comprises a ramp toward which the lever is elastically biased, a body defining cavities on opposite sides of the ramp and piping fluidly communicative with the cavities, and
the valve assembly increases pressure in the cavities via the piping to hydraulically drive the actuator movement.

6. The fail-fixed hydraulic actuator system according to claim 5 , further comprising an electronic controller receptive of data reflecting the actuator movement and configured to instruct the stepper motor assembly to operate accordingly.

7. The fail-fixed hydraulic actuator system according to claim 5 , wherein:
the cavities comprise first and second cavities at first and second sides of the ramp, respectively,
the piping comprises first and second piping fluidly communicative with the valve assembly and the first and second cavities, respectively, and
high and low pressure fluids from an engine system are communicated between the first and second cavities of the actuator and the valve assembly via the first and second piping, respectively.

8. The fail-fixed hydraulic actuator system according to claim 5 , wherein the valve assembly comprises:
a valve; and
a cam disposed to assume various angular positions to open or close the valve.

9. The fail-fixed hydraulic actuator system according to claim 5 , wherein the stepper motor assembly comprises:
a stepper motor; and
a gear train interposed between the stepper motor assembly and the valve assembly.

10. The fail-fixed hydraulic actuator system according to claim 9 , wherein the gear train comprises a reduction gear.

11. The fail-fixed hydraulic actuator system according to claim 5 , wherein the lever comprises:
an axle defining a rotational axis;
a first lever arm extending from the actuator to the axle; and
a second lever arm transversely oriented relative to the first lever arm and extending from the axle to the valve assembly.

12. A fail-fixed hydraulic actuator system, comprising:
a housing;
a valve comprising a spool movable relative to the housing in accordance with a valve state and a sleeve movable relative to the spool;
an actuator comprising a ramp, a body defining first and second cavities at first and second sides of the ramp, respectively, and first and second piping by which the first and second cavities are fluidly communicative with the spool, respectively, such that the actuator is hydraulically driven to move from an initial position upon a first movement of the spool relative to the housing until a second movement of the sleeve relative to the spool;
a cam disposed to assume various positions to change the valve state;
a stepper motor assembly that electromechanically controls the cam to occupy and move between the various positions to change the valve state and to thereby drive the first movement of the spool; and
a lever that is elastically biased toward the ramp and which drives the second movement of the sleeve responsive to actuator movement.

13. The fail-fixed hydraulic actuator system according to claim 12 , further comprising an electronic controller receptive of data reflecting the actuator movement and configured to instruct the stepper motor assembly to operate accordingly.

14. The fail-fixed hydraulic actuator system according to claim 12 , wherein high and low pressure fluids from an engine system are communicated between the first and second cavities and ports of the spool via the first and second piping, respectively.

15. The fail-fixed hydraulic actuator system according to claim 12 , wherein the cam is disposed to assume various angular positions to open or close the valve.

16. The fail-fixed hydraulic actuator system according to claim 12 , wherein the stepper motor assembly comprises:
a stepper motor; and
a gear train interposed between the stepper motor and the cam.

17. The fail-fixed hydraulic actuator system according to claim 16 , wherein the gear train comprises a reduction gear.

18. The fail-fixed hydraulic actuator system according to claim 12 , wherein the lever comprises:
an axle defining a rotational axis;
a first lever arm extending from the actuator to the axle; and
a second lever arm transversely oriented relative to the first lever arm and extending from the axle to the sleeve.

Assignees

• Hamilton Sundstrand Corp

Inventors

• Haugsjaahabink Todd

Classifications

• F15B2211/8623

  Electric supply failure · CPC title

• F15B2211/8752

  Emergency operation mode, e.g. fail-safe operation mode · CPC title

• F15B13/0444

  with rotary electric motor · CPC title

• F15B9/10

  in which the controlling element and the servomotor each controls a separate member, these members influencing different fluid passages or the same passage · CPC title

• F15B20/002 Primary

  Electrical failure · CPC title