Method of detecting failure of a servo-valve, and a servo-valve applying the method

• US 9,897,116 B2
• Filed: 10/09/2012
• Issued: 02/20/2018
• Est. Priority Date: 10/10/2011
• Status: Active Grant

• Current Assignee: Safran Aerosystems Hydraulics
• Original Assignee: In-Lhc
• Inventors: Ozzello, Guylain
• Primary Examiner(s): Price, Craig J
• Application Number:
  US13/647,924
• Publication Number:
  US 20130087223A1
• Time in Patent Office: 1,960 Days
• Field of Search: 13762561-62564, 13762566, 137 1, 137 14, 137551, 137553, 137554, 137556, 335 17, 335205-207, 25112912
• CPC Class Codes: F15B 13/0436 the pilot valves being of the steerable jet type
• CPC Class Codes: F15B 19/005 Fault detection or monitoring
• CPC Class Codes: H02K 11/20 for measuring, monitoring, testing, protecting or switching rectifiers H02K11/04; power electronics H02K11/33
• CPC Class Codes: H02K 26/00 Machines adapted to function as torque motors, i.e. to exert a torque when stalled
• CPC Class Codes: Y10T 137/0318 Processes
• CPC Class Codes: Y10T 137/0396 Involving pressure control
• CPC Class Codes: Y10T 137/2278 Pressure modulating relays or followers
• CPC Class Codes: Y10T 137/8158 With indicator, register, recorder, alarm or inspection means
• CPC Class Codes: Y10T 137/8242 Electrical
• CPC Class Codes: Y10T 137/8275 Indicator element rigidly carried by the movable element whose position is indicated
• CPC Class Codes: Y10T 137/86598 Opposed orifices; interposed modulator

Abstract

A method of detecting failure of a two-stage servo-valve in which the power-controlling movable member is connected to the rotor of a torque motor of a pilot stage by mechanical feedback. A malfunction signal is generated in response to detecting that the rotor of the torque motor has engaged a stop. The invention also provides a servo-valve for implementing such a method.

Claims

1. A method of detecting a failure of a servo-valve having a power stage with a movable member for distributing power and a pilot stage that includes a motor having a stationary portion and a movable magnetic flapper that occupies a position that is controlled in order to move the movable member for distributing power in controlled manner, said movable member for distributing power being connected to the movable magnetic flapper of the motor by a feedback member, the method including detecting the movable magnetic flapper of the motor engaging a magnetic stop in response to the closing of a switch and generating a malfunction signal in response to such detection,

wherein the malfunction signal indicates that the servo-valve is not functioning properly.

2. A method according to claim 1, wherein the movable magnetic flapper engaging the stop is detected by the switch operationally connected to the movable magnetic flapper of the motor in such a manner as to change state when the movable magnetic flapper of the motor engages the magnetic stop, with the change in state generating the malfunction signal.

3. A method according to claim 1, wherein the detecting includes the movable magnetic flapper engaging the magnetic stop to close the switch located adjacent to the magnetic stop, the switch is a dry contact or contactless switch.

5. The method according to claim 1, further comprising deactivating the servo-valve in response to the malfunction signal indicating that the servo-valve is not functioning properly.

4. A servo-valve comprising a power stage with a movable member for distributing power and a pilot stage that includes a motor having a stationary portion and a movable magnetic flapper that occupies a position that is controlled in order to move the movable member for distributing power in controlled manner, said movable member for distributing power being connected to the movable magnetic flapper of the motor by a feedback member, wherein the servo-valve is fitted with a detector for detecting the movable magnetic flapper of the motor engaging a magnetic stop, the detector includes a switch which, when closed, generates a malfunction signal,

wherein the malfunction signal indicates that the servo-valve is not functioning properly.

6. A servo-valve according to claim 4, wherein the switch is operationally connected to the movable magnetic flapper of the motor in such a manner as to change state when the movable magnetic flapper of the motor engages the magnetic stop.

7. The servo-valve according to claim 4, wherein the malfunction signal is generated in response to a break in the feedback member of the servo-valve.