Patent Publication Number: US-2023141259-A1

Title: Steering apparatus with a blocking device for limiting a steering angle of rotation, and steer-by-wire steering system with such a steering apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to German Priority Application No. 102021212670.7, filed Nov. 10, 2021, the disclosure of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The disclosure relates to a steering apparatus with a blocking device for limiting a steering angle of rotation, wherein the blocking device has a blocking element which is movable between a locking position and a release position, and with a shaft which is mounted rotatably about its centre longitudinal axis, wherein, in the locking position, the blocking element interacts with a blocking contour, which is connected to the shaft for rotation therewith, in order to stop a rotational movement of the shaft, and the blocking device has an electromagnetic or electromechanical actuator, wherein the blocking element is movable by the actuator for interaction with the blocking contour. Furthermore, the disclosure relates to a steer-by-wire steering system with such a steering apparatus. 
     BACKGROUND 
     In the case of a steer-by-wire steering system, there is no mechanical connection between a steering wheel and a steering gear. Steering commands are therefore transmitted by a control unit to an electric motor which, via the steering gear, displaces or moves a rack for steering the wheels. The rack can adjust a steering angle at the wheels by track rods here. The steering apparatus preferably has a feedback motor which simulates steering forces in order to provide the driver with feedback from the steering forces which are in action. 
     In the case of a conventional steering system with a mechanical connection between the steering wheel and the rack, the steering angle of rotation of a steering wheel is limited because of the predetermined mechanism. By contrast, due to the lack of a mechanical connection between the steering apparatus and the steering gear in a steer-by-wire steering system, it would be possible to rotate the steering wheel endlessly in a direction of rotation. However, there is thus the risk of overloading or damaging components of the steering apparatus. In addition, the driver requires feedback about the maximally achievable steering angle at the wheels. 
     The steering apparatus mentioned at the beginning therefore comprises a blocking device for limiting the steering angle of rotation. In particular, limiting the steering angle of rotation should be understood as meaning that the shaft of the steering apparatus and/or a steering wheel which is connected to the shaft can rotate only within a predetermined angular range and between two end stop positions. 
     SUMMARY 
     The disclosure relates to a steering apparatus. The steering apparatus can have a steering wheel or can be connected to a steering wheel. The term steering wheel is a synonym here for a steering handle of any shape and/or form. In particular, the steering apparatus is designed for a motor vehicle and/or for steering a motor vehicle. The steering apparatus has a blocking device for limiting a steering angle of rotation. The blocking device has a blocking element which is movable between a locking position and a release position. In particular, the blocking device and/or the blocking element is controllable. A control device can be provided for controlling the blocking device and/or the blocking element. The control device is preferably a component of the steering apparatus. In particular, the blocking device and/or the blocking element are/is controlled by signals from a steering angle of rotation sensor. 
     The steering apparatus has a shaft which is mounted rotatably about its centre longitudinal axis. In particular, the shaft is rotatable about the centre longitudinal axis in two directions of rotation directed facing away from each other. The steering angle of rotation and therefore the rotation of the shaft about its centre longitudinal axis in the two directions of rotation is limited or can be limited here by the blocking device. The blocking device preferably permits rotation of the shaft and/or of the steering wheel connected to the shaft only within a predetermined steering angle of rotation range and between two end stop positions which are predefined or can be predefined by the blocking device. The shaft can be designed or can be referred to as a steering shaft. Furthermore, the shaft can be formed integrally or in multiple parts. 
     The steering apparatus can have a feedback motor. In this case, the shaft can be set by the feedback motor into the rotational movement about the centre longitudinal axis of the shaft, in particular with the interconnection of a transmission, and/or can provide a controllable torque resistance. The driver of a vehicle or motor vehicle with such a steering apparatus can be provided with feedback from the steering forces acting on the wheels. In particular, the feedback motor is designed as an electric motor. 
     In the locking position, the blocking element interacts with a blocking contour, which is connected to the shaft for rotation therewith, in order to stop a rotational movement of the shaft. For this purpose, the blocking device has an electromagnetic or electromechanical actuator, wherein the blocking element is movable by the actuator in order to interact with the blocking contour. In particular in the locking position, the blocking element engages in the blocking contour. The blocking device and/or the blocking element is preferably arranged in a fixed position and/or immovably with respect to the shaft, for example on a housing or housing cover. 
     The steering angle of rotation in two directions of rotation directed facing away from one another can be limited and/or is limited by the blocking element, wherein both a first end stop position in a first direction of rotation and a second end stop position in a second direction of rotation opposed to the first direction of rotation can be predefined and/or is predefined by the blocking element and in interaction with the blocking contour. 
     It is advantageous here that a single blocking device and/or a single blocking element suffices to limit or to block the rotation of the shaft both in the first direction of rotation and in the second direction of rotation opposed to the first direction of rotation. Therefore, both the first end stop position and the second end stop position can be realized with a single blocking device and/or a single blocking element. A more compact and/or more cost-effective design is thereby made possible. It is possible to avoid having to provide two blocking devices, in order to be able to limit the steering angle of rotation in both directions of rotation. In particular, other arrangements are made possible. 
     According to a further exemplary arrangement, the blocking device has a restoring device for transferring the blocking element from the locking position into the release position. In particular, the restoring device here is designed as a non-mechanical restoring device. The restoring device is used to exert a force which acts on the blocking element and pulls or pushes the blocking element out of the blocking contour. 
     The restoring device can have a restoring element acting on the blocking element. The restoring device can act on the blocking element for transferring the blocking element from the locking position into the release position by a spring force. A corresponding restoring element can be designed as a spring, for example as a compression spring, spiral spring, leaf spring or wave spring. In particular, the restoring device and/or the restoring element acts counter to a movement of the blocking element for interacting with the blocking contour. When an actuator is activated, this force of the restoring device and/or of the restoring element is overcome, and therefore the blocking element is moved in the direction of the blocking contour counter to the force of the restoring device and/or of the restoring element. The blocking element can preferably be transferred back from the locking position and from an end stop position into the release position by the restoring device when the direction of rotation is reversed and/or an actuator is deactivated. It is therefore possible to ensure by the restoring device and/or the restoring element that the blocking element can be reliably transferred from the locking position into the release position. The blocking element is preferably held in the release position by the restoring device and/or the restoring element. This makes it reliably possible to prevent the blocking element from passing, when an actuator is deactivated and therefore unintentionally, from the release position into the locking position. 
     The restoring device can act on the blocking element for transferring the blocking element from the locking position into the release position by a magnetic force. The blocking element can therefore be moved from the locking position into the release position by magnetic force. In particular, the restoring device has a permanent magnet for interacting with a metal part or iron core. The permanent magnet is preferably arranged on or fastened to the blocking element. The metal part or the iron core can be part of the actuator. For example, the actuator can be designed as an electromagnet with an iron core. If such an actuator or such an electromagnet is deactivated, the permanent magnet and therefore the blocking element is pulled in the direction of the iron core. When an actuator is activated or an electromagnet is activated, the magnetic force between the permanent magnet of the blocking element and the iron core is overcome and, instead, the blocking element and the permanent magnet are repelled from the actuator. 
     According to a development, the blocking element is guided in a linearly displaceable manner in a guide. The guide can be designed as an integral or single-piece component of a housing or of a housing cover. In particular, a guide channel of the guide is formed in a housing or housing cover. The guide channel can extend parallel to the centre longitudinal axis of the shaft. A guide protrusion of the blocking element preferably engages slidably in the guide channel. 
     In particular, the blocking element is arranged in the guide in a manner displaceable parallel to the centre longitudinal axis of the shaft. This results in a particularly compact design of the steering apparatus with the blocking device. This arises in particular in comparison to another arrangement, in which the guide and/or a guide channel is arranged radially or at a right angle to the centre longitudinal axis of the shaft and therefore the blocking element is also arranged in the guide in a manner displaceable radially or at a right angle to the centre longitudinal axis of the shaft. 
     The blocking element can be designed in the manner of a bolt or in the manner of a piston. In particular, a portion of the blocking element that interacts with the blocking contour is designed in the manner of a bolt or in the manner of a piston. The blocking contour interacting with the blocking element in the locking position of the blocking element can be designed as a depression, in particular in the manner of a blind hole or in the manner of a groove or in the manner of an annular portion. 
     According to a further exemplary arrangement, the actuator is designed as a controllable electromagnet, in particular with an iron core, or as a cylindrical coil. According to the last-mentioned exemplary arrangement of the actuator, the actuator can therefore be designed as a solenoid. In particular if the actuator is designed as a cylindrical coil or as a solenoid, the actuator can be activated both for transferring the blocking element from the release position into the locking position and also for transferring the blocking element from the locking position into the release position. However, the actuator, in particular if the actuator is designed as a controllable electromagnet, is preferably activated for transferring the blocking element from the release position into the locking position and deactivated for transferring the blocking element from the locking position into the release position. In particular, the blocking element is transferred here from the locking position into the release position by the restoring device when the actuator is deactivated. 
     According to a development, an annular body which is connected to the shaft for rotation therewith has the blocking contour for interacting with the blocking element. The annular body is therefore arranged in a fixed position on the shaft and/or about the shaft or is held on the shaft. When the shaft rotates about its centre longitudinal axis, the annular body therefore rotates at the same time. The annular body has at least one blocking contour or a plurality of blocking contours for partially receiving and fastening the blocking element in the locking position. The blocking contour preferably has two mutually opposite stop surfaces for fastening the blocking element in the first end stop position or in the second end stop position. In particular, the stop surface acts counter to a further rotational movement of the shaft in the direction of rotation directed at the blocking element. The stop surface is preferably oriented radially with respect to the centre longitudinal axis of the shaft. In particular, the stop surface is oriented both radially and also parallel to the centre longitudinal axis of the shaft. 
     The annular body can be designed as a toothed wheel. The toothed wheel here can have a plurality of blocking contours on its outer circumference. In another example, the annular body can be designed as a worm wheel. The toothed wheel or the worm wheel can be connected to the feedback motor, in particular with the interposition of a transmission. When the annular body is designed as a worm wheel, at least one blocking contour or a plurality of blocking contours can be formed in an annular portion oriented at a right angle to the centre longitudinal axis. The annular portion is formed in particular between the shaft and an outer circumference of the worm wheel. 
     The at least one blocking contour is preferably designed such that, in the locking position of the blocking element, a rotational movement of the shaft from the first end stop position or from the second end stop position in a direction of rotation directed away from the respective end stop position is made possible. Thus, with a rotational movement which is directed in a direction of rotation directed away from the stop surface or the respective end stop position, the blocking element can be released from the stop surface or the blocking contour from the blocking element. In particular, the length of the at least one blocking contour in the direction of rotation of the shaft is greater than a width of the blocking element, which engages in the blocking contour, in the direction of rotation of the shaft. Therefore, after the respective end stop position is reached, a reversal of the direction of rotation or rotational movement is also made possible with the blocking element in the locking position. 
     Based upon detection of a rotational movement of the shaft from the first end stop position or from the second end stop position in a direction of rotation directed away from the respective end stop position, the actuator of the blocking element is deactivated. The blocking element can be transferred, in particular by the restoring device, from the locking position into the release position, and therefore a continuously proceeding rotational movement directed away from the respective end stop position is made possible. 
     According to a development, the blocking device and/or the blocking element and/or the actuator are/is arranged between two bearings, in particular two ball bearings, for the rotatable mounting on the shaft. This results in a particularly compact design. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The disclosure is explained in more detail below with reference to the figures. The same reference signs refer here to identical, similar or functionally identical components or elements. In the figures: 
         FIG.  1    shows a detail from a sectioned side view of a first steering apparatus according to the disclosure, and 
         FIG.  2    shows a detail from a sectioned side view of a further steering apparatus according to the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    shows a detail from a sectioned side view of a first steering apparatus  1  according to the disclosure. The steering apparatus  1  is part of a steer-by-wire steering system, not illustrated specifically here. The steering apparatus  1  is provided or designed here, by way of example, for a motor vehicle. The steering apparatus  1  has a shaft  2 . The shaft  2  is rotatable or is mounted rotatably about its centre longitudinal axis  3 . In this exemplary arrangement, the shaft  2  is formed from a plurality of components and therefore from multiple parts. Furthermore, in this exemplary arrangement, the shaft  2  is connectable or connected to a steering wheel, not illustrated specifically here. The shaft  2  is rotatable, in particular by the steering wheel, in two directions of rotation, which are directed facing away from each other, about the centre longitudinal axis  3 . 
     An annular body  4  is arranged on the shaft  2 . The annular body  4  is arranged on the shaft  2  for rotation therewith or in a fixed position thereon. When the shaft  2  rotates about the centre longitudinal axis  3 , the annular body  4  therefore rotates at the same time. A centre longitudinal axis of the annular body  4  coincides here with the centre longitudinal axis  3  of the shaft  2 . In this exemplary arrangement, the annular body  4  is designed as a worm wheel. The annular body  4  is connected to a feedback motor, not illustrated specifically here. The annular body  4  can therefore be driven by the feedback motor, as a result of which the shaft  2  is set into a rotational movement and/or a predefined or adjustable torque counteracts a rotation of the shaft  2 . As a result, steering feedback can be simulated for a driver. 
     The steering apparatus  1  has a housing  5  in which the shaft  2  is mounted rotatably by bearings  6 ,  7 . In this exemplary arrangement, the bearings  6 ,  7  are designed as ball bearings. Only part of the bearing  7  above the centre longitudinal axis  3  is illustrated here according to  FIG.  1   . 
     The steering apparatus  1  has a blocking device  8  for limiting a steering angle of rotation of the steering apparatus  1 . Based on the blocking device  8 , a rotational movement of the shaft  2  about the centre longitudinal axis  3  in two directions of rotation facing away from each other is therefore limited or can be limited in a variably adjustable manner. The blocking device  8  has a blocking element  9 . The blocking element  9  is movable between a locking position and a release position. In the illustration shown here, the blocking element  9  is in the release position. In this release position, the shaft  2  can rotate together with the annular body  4  in one of the two directions of rotation about the centre longitudinal axis  3 . 
     In order to stop the rotational movement of the shaft  2 , the blocking element  9  in the locking position interacts with a blocking contour  10  connected to the shaft  2  for rotation therewith. In this exemplary arrangement, the annular body  4  has the blocking contour  10 . The blocking contour  10  is designed here by way of example as a depression the manner of a blind hole. In particular, the blocking contour  10  has a form which is in the manner of an annular portion and is oriented about the centre longitudinal axis  3 . 
     Furthermore, just a single blocking contour  10  can be seen here. In another example, the annular body  4  can have a plurality of blocking contours  10 . The blocking contour  10  is formed here in an annular portion  11  of the annular body  4  that is oriented at a right angle to the centre longitudinal axis  3 . The annular portion  11  is therefore part of the annular body  4  and is arranged between the shaft  2  and an outer circumference of the annular body  4 . Furthermore, the blocking contour  10  is located on a side of the annular body  4  that faces the blocking element  9 . 
     The blocking element  9  has a portion  12  which is in the manner of a bolt and which faces the blocking contour  10 . In the locking position, not illustrated specifically here, the portion  12  in the manner of a bolt engages in the blocking contour  10 . 
     The blocking device  8  has an actuator  13  which, in this exemplary arrangement, is designed as an electromagnetic actuator. In detail, in this exemplary arrangement, the actuator  13  is realized as a controllable electromagnet. According to this example, this electromagnet has an iron core  14 . The blocking element  9  is movable by the activated actuator  13  in order to interact with the blocking contour  10  and in order to transfer from the release position into the locking position. 
     The blocking element  9  has a permanent magnet  15 . In this exemplary arrangement, the permanent magnet  15  is arranged on a side of the blocking element  9  that faces the actuator  13 . 
     Furthermore, the blocking element  9  is guided in a linearly displaceable manner in a guide  16 . In this case, the blocking element  9  is arranged in the guide  16  in a manner displaceable parallel to the centre longitudinal axis  3  of the shaft  2 . In this exemplary arrangement, the guide  16  has a guide channel  17  which is formed here in a housing cover  18 . The housing cover  18  is fastened to the housing  5  by suitable fasteners  19 , for example screws, in order to close the housing  5 . 
     For the transfer of the blocking element  9  out of the release position illustrated here into a locking position, the actuator  13  is activated. As a result, the blocking element  9  is pushed with the permanent magnet  15  away from the actuator  13  parallel to the centre longitudinal axis  3  on the basis of a magnetic force which is in effect and along the guide  16  into the blocking contour  10 . 
     In order to transfer the blocking element  9  from the locking position back into the release position, the blocking device  8  has a non-mechanically acting restoring device  20 . In this exemplary arrangement, the restoring device  20  is used to exert a magnetic force on the blocking element  9  for transferring the blocking element  9  from the locking position into the release position illustrated here. The permanent magnet  15  and the iron core  14  are part of the restoring device  20  here. In order to transfer the blocking element  9  from the locking position into the release position, the actuator  13  is deactivated. As a result, the permanent magnet  15 , and therefore the blocking element  9 , is pulled in the direction of the iron core and therefore in the direction of the actuator  13  such that the portion  12  in the manner of a bolt becomes disengaged from the blocking contour  10 . 
     The blocking contour  10  has two mutually opposite stop surfaces  21  for fastening the blocking element  9  in an end stop position. Only one of the two stop surfaces  21  can be seen here. The stop surfaces  21  are oriented radially and parallel to the centre longitudinal axis  3  of the shaft  2 . In the locking position, the blocking element  9  or the portion  12  of the blocking element  9  that is in the manner of a bolt strikes against one of the two stop surfaces  21  depending on the direction of rotation, as a result of which a further rotational movement of the shaft  2  and of the annular body  4  in the direction of rotation directed at the blocking element  9  is blocked. 
     In this exemplary arrangement, the blocking contour  10  is designed such that, in the locking position of the blocking element  9 , a rotational movement of the shaft  2  from the respective end stop position in a direction of rotation directed away from the respective end stop position is made possible. For this purpose, in this exemplary arrangement, the blocking contour  10  has a length, as seen in the direction of rotation of the shaft  2 , which length is greater than a width of the blocking element  9  engaging in the blocking contour, as seen in the direction of rotation of the shaft  2 . As a result, a reversal of the rotational movement out of the end stop position and with a blocking element  9  in the locking position is made possible. 
     On the basis of a detection of the rotational movement of the shaft  2  from the end stop position, the actuator  13  of the blocking element  9  is deactivated. As a result, the blocking element  9  passes, in particular by way of the restoring device  20 , from the locking position into the release position before the blocking element  9  strikes against the opposite stop surface  21 . The detection of the rotational movement, the deactivation and/or the activation of the actuator  13  can be undertaken by a control device, not illustrated specifically here. In particular, such a control device is connected to the actuator  13 . 
     The steering angle of rotation of the steering apparatus  1  in two directions of rotation directed facing away from each other can be limited by the blocking element  9 . In this case, both a first end stop position in a first direction of rotation and a second end stop position in a second direction of rotation opposed to the first direction of rotation can be predefined by the blocking element  9  and in interaction with the blocking contour  10 . 
       FIG.  2    shows a detail from a sectioned side view of a further steering apparatus  22  according to the disclosure. Identical features bear the same reference signs as previously. To this extent, reference is also made to the preceding description in order to avoid repetitions. 
     Instead of the blocking device  8  according to  FIG.  1   , the steering apparatus  22  which is illustrated here has a blocking device  23 . The blocking device  23  is likewise designed for limiting a steering angle of rotation of the steering apparatus  22 . For this purpose, the blocking device  23  has a blocking element  24 . The blocking element  24  is movable between a locking position and a release position, the blocking element  24  being illustrated here in the release position. In order to stop the rotational movement of the shaft  2 , the blocking element  24  in the locking position interacts with a blocking contour  25  which is connected to the shaft  2  for rotation therewith. 
     In this exemplary arrangement, a further annular body  26  has the blocking contour  25 . The further annular body  26  is connected to the shaft  2  for rotation therewith such that said annular body rotates together with the shaft  2  about the centre longitudinal axis  3 . Furthermore, in this exemplary arrangement, the annular body  26  is designed as a toothed wheel, with a plurality of blocking contours  25  on an outer circumference of the annular body  26  being designed as depressions. In this case, the blocking contours  25  in the manner of depressions extend from the outer circumference of the annular body  26  inwards radially with respect to the centre longitudinal axis  3 . 
     The blocking device  23  has an actuator  27  which is designed here as an electromagnetic actuator, namely as a cylindrical coil or as a solenoid. The blocking element  24  is guided in a linearly displaceable manner in a guide  28 . The guide  28  has a guide channel  29  for the blocking element  24 , the guide channel  29  in this exemplary arrangement being formed by interaction of portions of the housing  5  and of a housing cover  30 . In this exemplary arrangement, the blocking element  24  is guided in a linearly displaceable manner at a right angle to the centre longitudinal axis  3  by the guide  28 . When an actuator  27  is activated, the blocking element  24  is moved in the direction of the blocking contour  25  until the portion  12  of the blocking element  24  which is in the manner of a bolt engages in the blocking contour  25  and strikes against one of the two stop surfaces  21 . 
     Only one of the two stop surfaces  21  can be seen here. The stop surfaces  21  are oriented radially and parallel to the centre longitudinal axis  3  of the shaft  2 . In the locking position, the blocking element  24  strikes against one of the two stop surfaces  21  depending on the direction of rotation, as a result of which a further rotational movement of the shaft  2  and of the annular body  26  in the direction of rotation directed at the blocking element  24  is blocked. 
     In this exemplary arrangement, the blocking contour  25  is designed such that, in the locking position of the blocking element  24 , a rotational movement of the shaft  2  from the respective end stop position in a direction of rotation directed away from the respective end stop position is made possible. For this purpose, in this exemplary arrangement, the blocking contour  25  has a length, as seen in the circumferential direction of the annular body  26 , which length is greater than a width of the blocking element  24  that engages in the blocking contour  25 , as seen in the direction of rotation of the shaft  2 . As a result, a reversal of the rotational movement from the end stop position and with a blocking element  24  in the locking position is made possible. 
     On the basis of a detection of the rotational movement of the shaft  2  from the end stop position, the actuator  27  of the blocking element  24  is deactivated. As a result, the blocking element  24  passes, in particular by way of a restoring device  31 , from the locking position into the release position before the blocking element  24  strikes against the opposite stop surface  21 . The detection of the rotational movement, the deactivation and/or the activation of the actuator  27  can be undertaken by a control device, not illustrated specifically here. 
     In this exemplary arrangement, the restoring device  31  has a restoring element  32  acting on the blocking element  24 . The restoring element  32  is designed here as a helical compression spring.