Patent Publication Number: US-2021179161-A1

Title: Electrically adjustable steering column

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is related to and claims the benefit of French Patent Application Number 1914683 filed on Dec. 17, 2019, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to an electrically adjustable vehicle steering column, more particularly a steering column adjustable in height relative to a support base fixed to the vehicle chassis. 
     BACKGROUND 
     The steering column according to the disclosure is intended in particular but not exclusively for a motor vehicle. 
     Steering columns transmit the rotation of the steering wheel to the wheels to change their orientation, for example in the following order: steering wheel, steering column, intermediate axle, rack and pinion and finally the wheels. 
     Related art steering columns allow the steering wheel to be adjusted in depth and/or height. 
     A related art steering column includes:
         a steering member intended to be connected to a vehicle steering wheel,   a support base supporting this member in relation to the vehicle chassis,   adjustment means arranged to be able to change the height of the steering member in relation to this support base.       

     If you want to be able to adjust the tilt of the steering element electrically, it is known to use mechanisms using various levers to change the tilt of the steering element with the help of an electric actuator. Existing systems are relatively complex since they require a large number of components such as cantilever systems, columns, racks . . . . 
     The multiplication of connections and components within the steering column has an impact on the kinematics and the assembly process. In addition, when adjusting the height of a steering column via a cantilever, for example, there is a direct impact on the lower pivot. It is then necessary to add a degree of freedom on the lower pivot to avoid problems of hyperstatism. 
     BRIEF SUMMARY 
     A purpose of the present disclosure is to respond to the disadvantages of the above-mentioned prior art, in particular by reducing the number of connections necessary to allow height adjustment. The disclosure aims at proposing a less expensive solution in terms of parts but also in terms of assembly process. 
     For this purpose, a first aspect of the disclosure concerns a steering column comprising a support base intended to be fixedly mounted with respect to a vehicle chassis, a steering member intended to be connected to a vehicle steering wheel, said steering member being pivotally mounted with respect to said support base about a first transverse axis, a steering member tilt adjustment device for tilt adjustment with respect to the support base by pivoting the steering member about the first transverse axis. The steering column is characterized in that the steering member tilt adjustment device comprises an actuator which is pivotally mounted on the steering member about a second transverse axis substantially parallel to the first transverse axis. The actuator controls the translation of an actuating member which is articulated on the support base about a third transverse axis substantially parallel to the first transverse axis. 
     Thus the disclosure reduces costs by reducing the number of components, simplifying kinematics, and facilitating assembly. In particular, the disclosure allows lateral assembly of the entire steering member tilt adjustment device, without complex manipulations, since it is possible to mount the adjustment device on only one side of the steering column. The disclosure also makes it possible to reduce the mass of the steering column and the external dimensions. 
     According to an alternative embodiment of the disclosure, the translation direction of the actuator is substantially perpendicular to the second transverse axis. 
     According to an alternative embodiment of the disclosure, the actuating element is an adjusting screw. 
     According to an alternative embodiment of the disclosure, the adjusting screw is pivotally mounted on the support base and is movable in translation with respect to the actuator. 
     In an alternative embodiment of the disclosure, the adjusting screw is screwed into a nut which is pivotally mounted on the support base, the adjusting screw being fixed in relation to the actuator. 
     According to an alternative embodiment of the disclosure, the actuator is a geared motor. 
     According to an alternative embodiment of the disclosure, the part of the steering member which is directly mounted on the support base is called the lower body, and the lower body has a transverse second pivot pin which is provided for the pivot mounting of the actuator about the second transverse axis. 
     According to an alternative embodiment of the disclosure, the second pivot pin is made in one piece with the lower body or with the actuator body. 
     According to an alternative embodiment of the disclosure, the second pivot pin is a separate part which is mounted in a bearing on the lower body and in a bearing on the actuator body. 
     According to an alternative embodiment of the disclosure, the support base comprises two longitudinal members, which extend generally parallel to the steering member, and a transverse shaft which is attached to the two longitudinal members, one of the free ends of the transverse shaft forming a pivot for the articulation of the actuating member on the support base about the third pivot axis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other characteristics and advantages of the present disclosure will appear more clearly on reading the following detailed description of an embodiment of the disclosure given as an example, which is by no means restrictive and illustrated by the appended drawings, in which: 
         FIG. 1 ] is a perspective view which represents an example of a steering column according to a first embodiment of the disclosure; 
         FIG. 2 ] is a cross-section view according to Plane  2 - 2 , which represents the steering column of  FIG. 1 ; 
         FIG. 3 ] is a side view which represents the steering column of  FIG. 1  in a first tilted position; 
         FIG. 4 ] is a side view which represents the steering column of  FIG. 1  in a second tilted position; 
         FIG. 5 ] is a side view similar to that of  FIG. 3  representing a second embodiment of the disclosure; 
         FIG. 6 ] is a view similar to the one of  FIG. 2  which represents an alternative embodiment of the pivot connection between the actuator and the lower body of the steering column of  FIG. 1  in which a second pivot pin is arranged on the side of the actuator; 
         FIG. 7 ] is a view similar to the one of  FIG. 2 , which represents an alternative embodiment of the pivot connection between the actuator and the lower body of the steering column of  FIG. 1  in which the second pivot pin is separated from the actuator body and the lower body. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 to 4  illustrate a steering column  10  for a motor vehicle according to a first embodiment of the disclosure, integrating a support base  12 , also called a cap, for a steering member  14 . This support base  12  is intended to be fixed to the chassis of the vehicle (not shown), during the assembly of the latter. 
     The steering member  14  comprises a tube, known as the upper tube  16 , connected to a steering wheel nipple  18 , the latter being intended to be connected to the steering wheel (not shown) of the vehicle. The steering wheel nipple  18  forms the end of a steering shaft that is free to rotate about an axis of rotation. This rotation transmits the steering wheel rotations to the steering mechanisms (not shown) that cause the vehicle&#39;s wheels to steer. This axis of rotation is called the steering column axis A 1 . 
     The upper tube  16  is slidably mounted in a lower body  20  according to an axial adjustment axis, coaxial with the steering column axis A 1 . This sliding allows a depth adjustment of the steering wheel, also called axial adjustment. 
     The lower body  20 , is mounted freely rotating around a first pivot pin  22 , or pivot shaft, carried by the cap  12 . This is an example of a design allowing the articulation of the steering member  14  to the support base  12  by pivoting around a first pivot axis B 1 . This swivel allows radial adjustment of the steering wheel about the first pivot axis B 1 . The first pivot pin  22  is intended to be horizontal when the steering column  10  is mounted in the vehicle. This radial adjustment is also referred to as height adjustment or tilt adjustment. 
     In the following part of the description, the term transverse will be used, without limitation, to describe a direction that is substantially parallel to the first pivot axis B 1 . 
     The steering column  10  also has a steering member tilt adjustment device  24 . This steering member tilt adjustment device  24  comprises an electric actuator  26  which is pivotally mounted on the steering member  14  about a second transverse pivot axis C 1  which is substantially parallel to the first pivot axis B 1 . According to the design shown, the lower body  20  is provided with a second pivot pin  28 , or pivot shaft, which is fixed in relation to the lower body  20  and which extends on a side flank of the lower body  20 , on the left as seen in  FIG. 2 , to allow pivotal mounting of the actuator  26 . The second pivot pin  28  is here made in one piece with the lower body  20  and the actuator  26  has a bearing  30  designed to pivotally receive the free end of the second pivot pin  28 . 
     According to an alternative embodiment shown in  FIG. 6 , the second pivot pin  28  can be arranged directly on the actuator  26 , e.g. it can be made in one piece with the body of the actuator  26 , and the bearing  30  can be arranged on the lower body  20 . For the other parts, the structure of the steering column  10  and the steering member tilt adjustment device  24  remain the same. 
     According to another alternative embodiment shown in  FIG. 7 , the second pivot pin  28  is designed as a separate cylindrical part which is pressed into a bearing  30  formed on the body of the actuator  26  and into a bearing  30  formed on the lower body  20  in order to provide the pivot connection between the actuator  26  and the lower body  20 . For the other parts, the structure of the steering column  10  and the steering member tilt adjustment device  24  remain the same. 
     The steering member tilt adjustment device  24  furthermore comprises an actuating member  32  which is controlled by the actuator  26  and which is articulated on the support base  12  about a third transverse pivot axis D 1  so as to change the tilt of the steering member  14  relative to the support base  12  by means of a translational movement of the actuating member  32 . Thus, in addition to the first pivot pin  22 , the steering member  14  is connected to the support base  12  by two pivot connections, one arranged between the actuator body  26  and the lower body  20 , the other arranged between the actuator member  32  and the support base  12 . 
     Preferably the actuator  26  is a worm and gear motor gearbox which is designed to rotate an adjusting screw  34 . 
     According to the first embodiment shown in  FIGS. 1 to 4 , the actuator member  32  comprises the adjusting screw  34  and the nut  36 . The adjusting screw  34  is here intended to be rotated by the actuator  26  so that it rotates on itself about its axis, which corresponds to the translation direction T 1 . The adjusting screw  34  is here of the fixed type, i.e. it is locked in translation relative to the actuator  26 . The adjusting screw  34  cooperates with the nut  36  in such a way that it moves in the translation direction T 1 , through the nut  36 , relative to the support base  12 . This displacement is illustrated in  FIGS. 3 and 4 , which show the steering member  14  in two distinct tilted positions P 1 , P 2 , one at a first angle α 1  and the other at a second angle α 2  with respect to a horizontal plane H 1 . Nut  36  is here pivotally mounted around a transverse shaft  38  which is fixed on the support base  12 . 
     The second embodiment, which is shown in  FIG. 5 , differs from the first embodiment in that the adjusting screw  34  is of the movable type, i.e. it is movable in translation, along the translation direction T 1 , with respect to the actuator  26 . The nut  36  here comprises a threaded element driven in rotation by the actuator  26  in such a way as to cause a displacement of the adjusting screw  34  with respect to the actuator  26 . One end of the adjusting screw  34  is here provided with a bearing which is hinged to a free end of the transverse shaft  38  so that the adjusting screw  34  can be pivoted about the third pivot axis D 1 . 
     According to the embodiments shown, the support base  12  comprises a lower plate  40  which supports the first pivot pin  22 , two longitudinal members  42 ,  44  which extend generally parallel to the steering member  14  from the lower plate  40  to an upper plate  46 . The transverse shaft  38  is attached to the upper end of each longitudinal member  42 ,  44  which, together with the upper plate  46 , helps to stiffen the entire support base  12 . 
     Preferably, the nut  36 , according to the first embodiment, or the adjusting screw  34 , according to the second design, is hinged against a side wall of one longitudinal member  42 , on the opposite side to the other longitudinal member  44 . 
     The operation of the steering member tilt adjustment device  24  is now described according to the disclosure, in particular with reference to  FIGS. 3 and 4  of the first embodiment. 
     Starting from the first tilted position P 1  shown in  FIG. 3 , the geared motor is controlled in a first direction of rotation which causes a corresponding rotation of the adjusting screw  34 . By turning on itself, the adjusting screw  34  cooperates with the threads of the nut  36  which generates a translation of the adjusting screw  34  through the nut  36 , here upwards, until the geared motor stops. By moving upwards, the adjusting screw  34  causes the actuator  26  to move upwards, which in turn causes the steering member  14  to move upwards as well, since the actuator  26  and the steering member  14  are connected by the second pivot pin  28  and the bearing  30 . Thus, after the geared motor has stopped, the steering member  14  occupies the second tilted position P 2  shown in  FIG. 4 . Of course, by controlling the geared motor in the opposite direction, it is possible to control the pivoting of the steering member  14  in the opposite direction, in this case downwards. 
     It will be understood that various modifications and/or improvements obvious to the person skilled in the art may be made to the different embodiment of the disclosure described in the present description without going beyond the scope of the disclosure defined by the appended claims. 
     For example, according to an alternative embodiment (not shown), the position of actuator  26  and the position of actuator  32  could be reversed. That is, the actuator  26  could be pivotally mounted on the support base  12  and the actuator  32  could be pivotally mounted on the steering member  14 .