Brake force transducer for electric brakes

Abstract

An electric brake actuator and force transducer for the brake system of an aircraft is presented. A brake actuator includes a piston driven by a cylindrical nut and screw arrangement, driven by an appropriate motor of the actuator. Application of brake force results in a reactionary force that deflects the top cover of the actuator. The axial component of this deflection correlates directly with the brake force applied. A beam is interposed between this cover and a top cap, such that deflection of the beam correlates to applied brake face. Piezo-resistive devices are connected to the beam and, through a whetstone bridge, provide an electrical output signal correlating to applied brake force.

1 . A force transducer for an electric brake actuator, said force transducer adapted for interposition between a top cover and a cap of the brake actuator, said force transducer comprising:
 an elongated member adapted to be restrained at an outer portion thereof by the cap and at an inner portion thereof by the top cover, said elongated member receiving a biasing member centrally thereof and normal thereto, said biasing member being adjustably adapted to urge said elongated member away from the top cover and toward the cap, the biasing member being threadedly received by said elongated member and having an end thereof adapted to engage the top cover.   
   
   
       2 . The force transducer according to  claim 1 , wherein said elongated member is deflectable by a reactionary force applied to said inner portion where said member is restrained at said outer portion. 
   
   
       3 . The force transducer according to  claim 2 , wherein said force transducer comprises piezo-electric sensors connected to said elongated member. 
   
   
       4 . The force transducer actuator according to  claim 3 , wherein said piezo-electric sensors respond to movement of said elongated member resulting from and correlating with said reactionary force. 
   
   
       5 . The force transducer according to  claim 4 , wherein said elongated member comprises a beam and said sensors comprise piezo-electric devices on opposite sides of said beam. 
   
   
       6 . The force transducer according to  claim 5 , wherein said beam is of an enlarged mass in a center portion between opposite ends, said piezo-electric devices being positioned between said center portion and said end. 
   
   
       7 . The force transducer actuator according to  claim 6 , wherein said piezo-electric devices are connected to a bridge circuit for monitoring deflection of said beam. 
   
   
       8 . The force transducer according to  claim 7 , wherein said piezo-electric devices comprise piezo-electric resistors. 
   
   
       9 . The force transducer according to  claim 1 , wherein said elongated member comprises a beam, said beam having center and outer regions of a thickness substantially greater than a thickness of said beam therebetween. 
   
   
       10 . The force transducer according to  claim 9 , wherein said beam has a width between said thicker center and outer regions that is greatest adjacent said center region and tapers to a narrower width adjacent said outer region. 
   
   
       11 . The improvement of a brake force transducer according to  claim 10 , wherein said beam, has piezo-resistive devices attached to top and bottom surfaces thereof between said center and outer regions. 
   
   
       12 . A force transducer, comprising:
 an elongated member restrained at each of two opposite ends thereof, and configured for force application at a center region thereof; and   a plurality of sensors attached to said elongated member and responding to deflection of said elongated member.   
   
   
       13 . The force transducer according to  claim 12 , wherein said elongated member comprises a beam, said two opposite ends and said center region being of a thickness greater than the thickness of said beam between said center region and said two opposite ends. 
   
   
       14 . The force transducer according to  claim 13 , wherein said beam between said center region and said two opposite ends is of a larger width adjacent said center region, and tapered to a smaller width adjacent said ends. 
   
   
       15 . The force transducer according to  claim 14 , wherein said beam is symmetrical about said center region. 
   
   
       16 . The force transducer according to  claim 15 , wherein said sensors are uniformly and equidistantly spaced upon said beam. 
   
   
       17 . The force transducer according to  claim 16 , wherein said sensors comprise piezo-electric devices.