Patent ID: 7151324

Claim:
Electric steering lock for motor vehicles with a locking pin ( 10 ) which, with respect to a steering column ( 15 ), can move back and forth ( 14 ) between a locking end position ( 10 . 1 ) and an unlocking end position ( 10 . 2 ); with a device for detecting the position of the locking pin ( 10 ), comprising: a permanent magnet ( 20 ) and two different Hall sensors ( 21 , 22 ), which are connected to an evaluator ( 19 ); where the permanent magnet ( 20 ) or the Hall sensors ( 21 , 22 ) move back and forth ( 14 ) along with the locking pin ( 10 ) and where, during this concomitant movement ( 14 ), a pole transition ( 23 ) of the permanent magnet ( 20 ) passes over the Hall sensors ( 21 , 22 ), and one sensor ( 21 ) monitors the locking position ( 10 . 1 ), while the other sensor ( 22 ) monitors the unlocking position ( 10 . 2 ), wherein, both sensors ( 21 , 22 ) are digital, one of the sensors ( 22 ) is S-active, whereas the other sensor ( 22 ) is N-active, the two Hall sensors ( 21 , 22 ) are mounted in an intermediate space ( 25 ) between the two end positions ( 10 . 1 , 10 . 2 ) of the pole transition ( 23 ) of the permanent magnet ( 20 ) and have a defined final distance ( 38 ; 39 ) in the two end positions ( 10 . 1 , 10 . 2 ), when in one end position ( 10 . 1 ), the N-active sensor ( 21 ) faces the north pole of the permanent magnet ( 20 ), and when in the other end position ( 10 . 2 ) the S-active sensor ( 22 ) faces the south pole of the permanent magnet ( 20 ), and the final distance ( 38 ; 39 ) corresponds to a distance at which the magnetic flux density ( 30 . 1 ) of the permanent magnet ( 20 ) at a highest temperature which can occur during operation is at least equal to a threshold value ( 22 . 1 , 21 . 1 ) required to turn on ( 26 . 1 , 27 . 1 ; 28 . 1 , 29 . 1 ) the N- or S-active sensor ( 22 ; 21 ).