Apparatus for detecting a vibratory movement of a laundry drum

Abstract

An apparatus detects a vibratory movement of the rotary shaft of an internal unit, which is suspended such that it can vibrate, of a washing machine having a laundry drum which is driven by an electric motor. The apparatus has a sensor part and a measured-value detector which is connected to the rotary shaft and provides a measured variable which varies periodically with the rotational speed of the rotary shaft and periodically with the vibratory movement in at least one direction parallel to the axis of rotation or in at least one radial direction.

1 . An apparatus for detecting a vibratory movement of a rotary shaft of an internal unit of a washing machine, the washing machine having a laundry drum driven by an electric motor, the internal unit being suspended for allowing the internal unit to vibrate, the apparatus comprising: 
 a sensor part; and    a measured-value detector connected to the rotary shaft and providing a measured variable varying periodically with a rotational speed of the rotary shaft and periodically with the vibratory movement in at least one direction parallel to an axis of rotation of the rotary shaft or in at least one radial direction.    
     
     
         2 . The apparatus according to  claim 1 , further comprising an acceleration sensor, said sensor part and said measured-value detector are parts of said acceleration sensor.  
     
     
         3 . The apparatus according to  claim 1 , wherein said measured-value detector is connected to a rotor of the electric motor or to a drum-bearing shaft.  
     
     
         4 . The apparatus according to  claim 1 , wherein said measured-value detector influences a rotary-encoder signal, which represents the rotational speed of the electric motor or the laundry drum, by modulating a pulse width, a frequency or an amplitude.  
     
     
         5 . The apparatus according to  claim 1 , wherein said measured-value detector has an actuator part which is fixed in terms of rotation with respect to the axis of rotation.  
     
     
         6 . The apparatus according to  claim 5 , wherein said measured-value detector has an actuator part which can move axially and/or radially with respect to the axis of rotation.  
     
     
         7 . The apparatus according to  claim 6 , wherein said actuator part which is fixed in terms of rotation and said actuator part which can move are coupled to one another such that they can rotate.  
     
     
         8 . The apparatus according to  claim 4 , further comprising two stops, said measured-value detector is mounted such that it can move and whose ability to move is limited by said two stops.  
     
     
         9 . The apparatus according to  claim 8 , wherein said measured-value detector is formed in such a way that a ratio of a division predefined by said measured-value detector changes as a result of the vibratory movement.  
     
     
         10 . The apparatus according to  claim 9 , wherein said measured-value detector has a device with a toothed or perforated division.  
     
     
         11 . The apparatus according to  claim 9 , wherein said measured-value detector is formed in such a way that a different division ratio is produced at each of said two stops, being mutually opposite stops, on account of an axial or radial movement, resulting from a vibratory movement, of said measured-value detector or of a part thereof in relation to said sensor part being a fixed position sensor part.  
     
     
         12 . The apparatus according to  claim 11 , wherein changes in the division ratio vary periodically with the vibratory movement.  
     
     
         13 . The apparatus according to  claim 12 , wherein a periodic change in the division ratio in the electric motor is included in a change in a mark/space ratio of the rotary-encoder signal generated during detection of the rotational speed.  
     
     
         14 . The apparatus according to  claim 1 , wherein at least one of said measured-value detector and said sensor part is integrated in a rotational-speed sensor that is connected to the rotary shaft.  
     
     
         15 . The apparatus according to  claim 1 , wherein said sensor part is a forked light barrier.  
     
     
         16 . The apparatus according to  claim 1 , wherein said sensor part can move axially and/or radially with respect to the axis of rotation.  
     
     
         17 . The apparatus according to claim l, wherein said sensor part can move radially and said measured-value detector or a part thereof can move axially with respect to the axis of rotation.  
     
     
         18 . The apparatus according to  claim 1 , wherein said sensor part can move axially and said measured-value detector or a part thereof can move radially with respect to the axis of rotation.  
     
     
         19 . The apparatus according to  claim 16 , wherein said measured-value detector has two mutually opposite stops, said sensor part produces a different division ratio at each of said mutually opposite stops on account of an axial and/or radial movement, resulting from a vibratory movement.