Steering column assembly for a vehicle

Abstract

A steering column assembly for a vehicle comprises an elongate steering column mounted for rotation about its longitudinal axis and configured for attachment of a steering wheel at one end. A first gear is connected to the steering column at a location spaced from where the steering wheel is attached and is configured to rotate with the steering column. The assembly has first and second motors, each having an output shaft and first and second worm screws directly connected to and rotatable with the output shaft of the first and second motors, respectively and engaged with the first gear, and a control arrangement is configured to operate the first and second motors. A motor position sensor arrangement senses the rotational position of the motor output shafts, each sensor arrangement comprising a target member fixedly mounted to a respective motor output shaft on an opposite side of the worm screw from the motor and a sensor for detecting the target member. The control arrangement comprises a substantially planar circuit board carrying one or more electrical and/or electronic components, the plane of the circuit board being inclined to the longitudinal axis of the steering column.

1 . A steering column assembly for a vehicle, comprising:
 an elongate steering column mounted for rotation about its longitudinal axis and configured for attachment to a steering wheel at one end;   a first gear connected to the steering column at a location spaced from a portion of the steering column where the steering wheel is attached, the first gear configured to rotate with the steering column;   first and second motors, each having an output shaft;   first and second worm screws directly connected to and rotatable with the output shaft of the first and second motors respectively and engaged with the first gear;   a control arrangement configured to operate the first and second motors; and   a motor position sensor arrangement for sensing the rotational position of the motor output shafts, each sensor arrangement comprising a target member fixedly mounted to a respective motor output shaft on an opposite side of the worm screw from the motor and a sensor for detecting the target member;   wherein the control arrangement comprises a substantially planar circuit board carrying one or more electrical and/or electronic components, a plane of the circuit board being inclined to the longitudinal axis of the steering column.   
     
     
         2 . A steering column assembly as claimed in  claim 1 , wherein the plane of the circuit board is substantially perpendicular to the longitudinal axis of the steering column. 
     
     
         3 . A steering column assembly as claimed in  claim 1 , wherein rotational axes of the output shafts of the first and second motors are substantially parallel. 
     
     
         4 . A steering column assembly as claimed in  claim 3 , wherein the plane of the circuit board is substantially parallel to the rotational axes of the output shafts of the first and second motors. 
     
     
         5 . A steering column assembly as claimed in  claim 1 , wherein the first gear is connected to the steering column at the opposite end of the steering column from the steering wheel. 
     
     
         6 . A steering column assembly as claimed in  claim 1 , wherein each target member is mounted to one end of a respective motor output shaft. 
     
     
         7 . A steering column assembly as claimed in  claim 1 , wherein each motor is mounted at one end of a respective motor output shaft. 
     
     
         8 . A steering column assembly as claimed in  claim 1 , further comprising a bearing for the output shaft of each motor, located between the respective worm screw and the target member. 
     
     
         9 . A steering column assembly as claimed in  claim 1 , wherein each target member comprises a magnetic member. 
     
     
         10 . A steering column assembly as claimed in  claim 1 , wherein each target member comprises a variable reluctance resolver. 
     
     
         11 . A steering column assembly as claimed in  claim 1 , wherein the sensors for detecting the target members are located at or adjacent to ends of the motor output shafts on opposite side of the worm screws from the motors. 
     
     
         12 . A steering column assembly as claimed in  claim 1 , further comprising a second circuit board on which the sensors for detecting the target members are mounted. 
     
     
         13 . A steering column assembly as claimed in  claim 1 , wherein the worm screws are positioned on opposite sides of the rotational axis of the first gear. 
     
     
         14 . A steering column assembly as claimed in  claim 12 , wherein the worm screws are positioned at diametrically opposite sides of the rotational axis of the first gear. 
     
     
         15 . A steering column assembly as claimed in  claim 1 , wherein the first and second worm screws form part of the output shaft of the first and second motors respectively. 
     
     
         16 . A steering column assembly as claimed in  claim 1 , wherein the rotational axes of the output shafts of the first and second motors are oriented substantially perpendicularly to the rotational axis of the steering column. 
     
     
         17 . A steering column assembly as claimed in  claim 1 , wherein the first and second motors are positioned below the first and second worm screws respectively. 
     
     
         18 . A vehicle comprising a steering column assembly as claimed in  claim 1 . 
     
     
         19 . A steering column assembly as claimed in  claim 3 , wherein each target member is mounted to one end of a respective motor output shaft. 
     
     
         20 . A steering column assembly as claimed in  claim 19 , wherein each target member comprises a magnetic member.