Piezo-Based Encoder with Magnetic Brake for Powered Window Closing

Abstract

The device ( 1 ) comprises a frame ( 42 ) comprising a static magnetic pole ( 48 ), a movable member ( 44 ) relatively to the frame ( 42 ), the movable member ( 44 ) comprising a moving magnetic pole ( 46 ), the static magnetic pole ( 48 ) and the moving magnetic pole ( 46 ) being magnetically coupled in some position of the movable member ( 44 ), a piezosensitive element ( 50 ) so that the force due to the magnetic coupling between the moving magnetic pole ( 46 ) and the static magnetic pole ( 48 ) reacts on the piezosensitive element ( 50 ), and means ( 52, 54, 56, 58 ) for outputting an electric signal from the piezosensitive element ( 50 ), the signal being useful in determining the position and/or the speed and/or the direction of the movable member ( 44 ).

1 - 19 . (canceled)  
   
   
       20 . A device ( 1 ) comprising: 
 a motor housing ( 42 ) of a motor ( 32 ), comprising a static magnetic pole ( 48 ),    a rotor ( 44 ) of the motor ( 32 ), that can rotate inside the motor housing ( 42 ), the rotor ( 44 ) comprising a moving magnetic pole ( 46 ), the static magnetic pole ( 48 ) and the moving magnetic pole ( 46 ) being magnetically coupled in some position of the rotor ( 44 ),    a piezosensitive element ( 50 ) so that the force due to the magnetic coupling between the moving magnetic pole ( 46 ) and the static magnetic pole ( 48 ) reacts on the piezosensitive element ( 50 ), and    means ( 52 ,  54 ,  56 ,  58 ) for outputting an electric signal from the piezosensitive element ( 50 ), the signal being useful in determining the position and/or the speed and/or the direction of the rotor ( 44 ).    
   
   
       21 . The device as claimed in  claim 20 , wherein the piezosensitive element ( 50 ) is fixed to the motor housing ( 42 ).  
   
   
       22 . The device as claimed in  claim 20 , wherein the static magnetic pole is a magnet ( 48 ).  
   
   
       23 . The device as claimed in  claim 20 , which comprises: 
 a first static magnetic pole and a first piezosensitive element,    a second static magnetic pole and a second piezosensitive element, the static magnetic poles being fixed to the frame via the piezosensitive elements so that the force due to the magnetic coupling between the moving magnetic poles and the static magnetic poles stresses the piezosensitive element, these poles being disposed with an angular offset different from 180°.    
   
   
       24 . The device as claimed in  claim 23 , wherein the angular offset is equal to about 90°.  
   
   
       25 . A device ( 4 ) comprising: 
 a stator tube ( 201 ) of a switching flux linear motor, comprising a pad ( 202 ) made of ferromagnetic material,    a sliding element ( 400 ) of the switching flux linear motor, sliding relatively to the stator tube ( 201 ), the sliding element ( 400 ) comprising a magnetized element ( 209 ,  210 ), the pad ( 202 ) made of ferromagnetic material and the magnetized element ( 209 , 210 ) being magnetically coupled in some position of the sliding element ( 400 ),    a piezosensitive element ( 300 ,  232 ) so that the force due to the magnetic coupling between the magnetized element ( 209 ,  210 ) and the pad ( 202 ) reacts on the piezosensitive element ( 300 ,  232 ), and    means ( 52 ,  54 ,  56 ,  58 ) for outputting an electric signal from the piezosensitive element ( 300 ,  232 ), the signal being useful in determining the position and/or the speed and/or the direction of the sliding element ( 400 ).    
   
   
       26 . The device as claimed in  claim 25 , wherein the piezosensitive element ( 300 ) is fixed to the stator tube ( 201 ).  
   
   
       27 . The device as claimed in  claim 25 , wherein the magnetized element ( 210 ) comprises a permanent magnet ( 231 ) and a piece of ferromagnetic material ( 230   a ), the piezosensitive element ( 232 ) being sandwiched between the permanent magnet ( 231 ) and the piece of ferromagnetic material ( 230   a ).  
   
   
       28 . The device as claimed in  claim 20 , wherein the motor is a rotating brushless motor, in that the rotor comprises at least a permanent magnet being the moving magnetic pole, and in that the static magnetic pole is a pad made of ferromagnetic material secured on the stator.  
   
   
       29 . The device as claimed in  claim 28 , wherein the piezosensitive element is sandwiched between the static magnetic pole and the stator.  
   
   
       30 . The device as claimed in  claim 28 , wherein the piezosensitive element is sandwiched between the permanent magnet and a piece of ferromagnetic material.  
   
   
       31 . The device as claimed in  claim 20 , wherein the means for outputting an electric signal from the piezosensitive element comprise leads ( 52 ,  54 ), an amplifier ( 56 ) and a processing circuit ( 58 ).  
   
   
       32 . The device as claimed in  claim 20 , wherein the piezosensitive element is a piezoelectric element.  
   
   
       33 . The device as claimed in  claim 20 , wherein the piezosensitive element is a resistor.  
   
   
       34 . A powered assembly ( 10 ) including: 
 an object ( 16 ) that is selected from the group consisting of window coverings, roller blinds, awnings, skylight coverings, curtains, and screens and that can be moved between a first configuration and a second configuration, and    a device as claimed in  claim 20 , the movable element of the device being mechanically coupled to the object ( 16 ).    
   
   
       35 . The use of an electric signal output from a device according to  claim 20  for controlling the electric power supply of an element of a motor.