Patent Publication Number: US-2023132966-A1

Title: Rotation limitation module and steering wheel module for a steer-by-wire steering system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to German Priority Application No. 102021212303.1, filed Nov. 2, 2021, the disclosure of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The disclosure relates to a rotation limitation module for a steer-by-wire steering system, having a housing in which a shaft portion that is rotatable about a central axis and that is able to be coupled in a rotationally fixed manner to a steering wheel shaft or is configured as a portion of the steering wheel shaft is received. The disclosure is also directed toward a steering wheel module for a steer-by-wire steering system, which comprises a steering wheel, which is fastened to a first end of a steering wheel shaft, and a rotation limitation module of the type mentioned at the outset, the rotation limitation module being provided on a second end of the steering wheel shaft that faces away from the steering wheel. 
     BACKGROUND 
     Steering wheel modules and rotation limitation modules of this type are known from the prior art. To some extent, the components of steering wheel modules are collectively also referred to as a hand wheel actuator or as a torque feedback unit. However, these terms usually do not include the steering wheel. As also already suggested by these designations, known steering wheel modules are configured, inter alia, for generating a torque which supplies to the driver mechanical feedback in the form of a restoring moment. 
     Rotation limitation modules are sometimes also referred to as mechanical torque limiters, this being based on the fact that the introduction of a torque into the steering wheel module is limited as a result of the activation of the steering wheel. Accordingly, rotation limitation modules are used in steer-by-wire steering systems in order to limit a rotation of the steering wheel in both rotation directions, said steering wheel in such steering systems no longer being mechanically coupled to a steering gear on the axle. It is ensured in this way, for example, that wiring for electrical systems disposed in the steering wheel is not damaged. Rotation limitation modules are usually configured such that they permit a rotation of the steering wheel in both directions by, for example, 540°, thus 1.5 revolutions. Moreover, rotation limitation modules for safety reasons have to be embodied so that they also function in the event of a failure of an electric power supply. 
     SUMMARY 
     What is needed is to further improve known rotation limitation modules and steering wheel modules equipped therewith. A rotation limitation module which is of simple and cost-effective construction is the aim of the disclosure. 
     A rotation limitation module of the type mentioned at the outset is disclosed, which has a limiter disk which by way of a sliding guide is coupled in a rotationally fixed manner to the shaft portion and has an external thread which is driven into an internal thread of the housing. A housing portion, which delimits the housing in a first axial direction along the central axis, supports a first detent geometry. A housing portion, which delimits the housing in a second axial direction, counter to said first axial direction, along the central axis, supports a second detent geometry. Moreover, provided on a side of the limiter disk that faces the first detent geometry is a first counter-detent geometry, which, for limiting a rotation of the shaft portion in a first rotation direction, is configured for contacting the first detent geometry. Provided on a side of the limiter disk that faces the second detent geometry is a second counter-detent geometry which, for limiting a rotation of the shaft portion in a second rotation direction, counter to the first rotation direction, is configured for contacting the second detent geometry. In one exemplary arrangement, the limiter disk is a singular limiter disk. 
     The basic concept of the disclosure lies in providing a rotation limitation module having a single limiter disk which is mounted so as to be rotationally fixed but axially displaceable on the shaft portion. Moreover, the limiter disk is guided in the housing by way of a thread. When the shaft portion is now rotated in a first rotation direction, the limiter disk is conjointly rotated and, by virtue of the effect of the thread, displaced in a first axial direction. The limiter disk, more specifically the first counter-detent geometry thereof, in the process runs onto a housing portion, for example, a first detent geometry, when said limiter disk has overcome a predefined maximum distance along the first axial direction. This predefined maximum distance is adapted to a maximum angle of rotation of the shaft portion such that the shaft portion and the steering wheel, which is coupled thereto, are limited in terms of rotation in the first rotation direction. The maximum angle of rotation of the shaft portion here corresponds directly or indirectly to a maximum steering wheel angle. When the shaft portion is rotated in a second rotation direction, counter to the first rotation direction, the limiter disk is likewise conjointly rotated and, by virtue of the effect of the thread, displaced in a second axial direction which is counter to the first axial direction. In this axial direction, the limiter disk, more specifically the second counter-detent geometry thereof, also runs onto a housing portion, more specifically the second detent geometry, when said limiter disk has overcome a predefined maximum distance along the second axial direction. The predefined maximum distance in the second axial direction is also adapted to a maximum permissible angle of rotation, such that a rotation limitation for the shaft portion and the steering wheel, which is coupled thereto, is also implemented in this direction. The maximum angle of rotation of the shaft portion again corresponds directly or indirectly to a maximum steering wheel angle. 
     The rotation limitation module according to the disclosure comprises only a few components, for example, a few moving components. The coupling between the limiter disk and the shaft portion here is performed by way of a sliding guide which can be produced in a simple and cost-effective manner using standard methods and production plants. The same applies to the coupling between the limiter disk and the housing by way of a thread. The entire rotation limitation module is thus constructed in a simple and cost-effective manner. Moreover, the rotation limitation module is extremely compact. In addition, the rotation limitation module according to the disclosure causes only comparatively little noise during operation. Moreover, the potential noise caused by the rotation of the limiter disk in the thread of the housing is uniform, Noise which a user could perceive as irritating is thus avoided overall. This is particularly true in comparison to known rotation limitation modules in the operation of which a plurality of moving elements have to be successively entrained and numerous mechanical contacts take place before the actual rotation limitation is reached, said mechanical contacts in each case being associated with a noise. Moreover, the limitation module can be adjusted in a simple and precise manner in that a spacing in the axial direction between the limiter disk and the housing-proximal detent geometries is chosen such that a desired maximum angle of rotation for the shaft portion results. The axial displacement which is imparted to the limiter disk by virtue of a relative rotation in relation to the housing in the process can be very easily determined by way of the thread pitch. 
     In this context, the sliding guide comprises a toothing which runs purely in the axial direction, for example. It is also possible for the sliding guide to be implemented by bevels provided on the shaft portion. 
     According to one exemplary arrangement, the first detent geometry is configured on an axial protrusion of the associated housing portion that points into the interior of the housing. Alternatively, or additionally, the second detent geometry is configured on an axial protrusion of the associated housing portion that points into the interior of the housing. Alternatively, or additionally, the first counter-detent geometry is configured on an axial protrusion of the limiter disk. Alternatively, or additionally, the second counter-detent geometry is configured on an axial protrusion of the limiter disk. In other words, at least one detent geometry is configured on an axial protrusion of the associated housing portion, or at least one counter-detent geometry is configured on an axial protrusion of the limiter disk. The at least one detent geometry and/or the at least one counter-detent geometry can thus be produced with high precision. Moreover, the provision of an axial protrusion has the effect that the rotation limitation module can be easily rotated back from an operating situation in which a counter-detent geometry contacts the assigned detent geometry. In other words, it is avoided in this way that the limiter disk is undesirably jammed or braced in the housing. 
     The axial protrusion that supports the first detent geometry and/or the axial protrusion that supports the second detent geometry and/or the axial protrusion that supports the first counter-detent geometry and/or the axial protrusion that supports the second counter-detent geometry in the circumferential direction here can extend across 45 angular degrees or less. In one exemplary arrangement, the extent is across 30 angular degrees or less. The axial protrusions are thus embodied in a comparatively compact manner such that an overall compact construction of the rotation limitation module results. 
     It is also possible for the axial protrusion that supports the first detent geometry and/or the axial protrusion that supports the second detent geometry and/or the axial protrusion that supports the first counter-detent geometry and/or the axial protrusion that supports the second counter-detent geometry in the radial direction to be at least 1.5 mm in length. In one exemplary arrangement, the axial protrusion is at least 3 mm in length. Installation space in the radial direction is thus utilized for a sufficiently large design of the detent geometry and/or the counter-detent geometry. In this way, mechanical stresses in the housing and/or the limiter disk can be kept to a low level. The installation space in the radial direction here is usually less critical, i.e. typically available, in comparison to installation space in the axial direction. The installation spaces available are thus cleverly utilized by the rotation limitation module according to the disclosure. 
     In one alternative arrangement, the axial protrusion that supports the first detent geometry is furthermore configured so as to be integral to the associated housing portion. Alternatively or additionally, the axial protrusion that supports the second detent geometry is configured so as to be integral to the associated housing portion. In this way, the detent geometries can be produced in a cost-effective manner. Assembling the detent geometries on the housing is consequently not necessary. 
     The axial protrusion that supports the first counter-detent geometry can moreover be configured so as to be integral to the limiter disk, or be provided on a detent component that is held so as to be elastically displaceable on the limiter disk. Alternatively or additionally, the axial protrusion that supports the second counter-detent geometry can be configured so as to be integral to the limiter disk, or be provided on a detent component which is held so as to be elastically displaceable on the limiter disk. The integral exemplary arrangement of the counter-detent geometries has the advantage that the limiter disk, including the counter-detent geometries, can be produced in a simple and cost-effective manner. No assembly operations are obviously required. In comparison, providing the counter-detent geometries on a detent component has the advantage that the detent can be provided with a damping characteristic such that the user experiences a comparatively soft rotation limitation. 
     In the case of both counter-detent geometries being provided on a detent component, a common detent component which supports both counter-detent geometries can be used. A simple construction results in this way. 
     In one exemplary arrangement, the first detent geometry and/or the second detent geometry and/or the first counter-detent geometry and/or the second counter-detent geometry are/is configured as detent faces. This has the advantage that the forces which are transmitted during contact between mutually assigned detent geometries and counter-detent geometries result in only comparatively minor mechanical stresses in the assigned components. The mutually assigned detent geometries and counter-detent geometries thus bear on one another in a planar manner. In this way, the forces which are to be transmitted when a detent is contacted are distributed in the detent face. As a result, the rotation limitation module has a comparatively high level of reliability and a comparatively long service life. 
     In one exemplary arrangement, the detent faces are substantially flat. 
     The first detent geometry and/or the second detent geometry and/or the first counter-detent geometry and/or the second counter-detent geometry in terms of the central axis can be oriented substantially in the circumferential direction. A geometry which is oriented in the circumferential direction here is understood to mean that a normal points in the circumferential direction. In the case of the detent geometries and/or the counter-detent geometries being configured as flat detent faces, the latter thus extend in the axial direction and in the radial direction. The limiter disk thus impacts the respectively relevant housing portion in the circumferential direction, Jamming or bracing of the rotation limitation module is avoided in this way. The limiter disk and the shaft portion can thus also be easily rotated back from a detent situation. 
     When viewed in the radial direction, a first axial spacing between the housing portion, which supports the first detent geometry, and the limiter disk, and a second axial spacing between the housing portion, which supports the second detent geometry, and the limiter disk are chosen such that the end sides of the respective axial protrusion do not impact the housing, the housing lid and the limiter disk in the event of maximum rotation. In this way, these axial spacings depend on the angle of rotation required. 
     In one exemplary arrangement, the first axial spacing and the second axial spacing in cumulative terms are greater than or equal to a pitch of the external thread of the limiter disk. Furthermore, the first axial spacing and the second axial spacing in cumulative terms are greater than or equal to 1.5 times a pitch of the external thread of the limiter disk. Since the external thread of the limiter disk is driven into an internal thread of the housing, the same naturally also applies to the internal thread. A pitch of a thread here is understood to mean the axial distance traveled as a result of one revolution. This corresponds to an axial spacing between two crests of the thread. The pitch of a thread is in some instances also referred to as the lead. The axial spacings here are in each case determined as the spacings of mutually closest points of the respective housing portion and of the limiter disk. The axial protrusions that support the detent geometries and counter-detent geometries thus potentially have the effect of reducing the spacing. The angle of rotation permitted by the rotation limitation module can be adjusted by way of the axial spacings. In one exemplary arrangement in which a detent geometry and/or a counter-detent geometry are/is not provided on the entire circumference, it has to be additionally taken into account here, however, that the counter-detent geometry in a certain way can plunge into the assigned housing portion such that an axial spacing of zero is not equivalent to an impact on the detent. An axial protrusion that supports a detent geometry, and an assigned axial protrusion that supports a counter-detent geometry, can thus still be rotatable relative to one another even in an operating state in which said axial protrusions overlap in the axial direction. In the event that the cumulative axial spacings correspond to a pitch of the thread, the limiter disk, proceeding from a center position, can thus perform half a revolution in each direction before the respective counter-detent geometry in the axial direction potentially plunges into the associated housing portion. For determining the actual detent, it is additionally to be considered how far the limiter disk in the plunged state can be rotated in relation to the assigned housing portion. 
     In one exemplary arrangement, at least an axial end side of the limiter disk or an axial end side of the housing portion that supports the first detent geometry, or an axial end side of the housing portion that supports the second detent geometry, at least in portions are/is covered by an elastically deformable shock-absorbent material. In this way, a rotation limitation is perceived to be soft by a user. Said user, when rotating the steering wheel, senses a gradually increasing resistance before any further rotation is no longer possible. The shock-absorbent material is, for example, an elastomer material. 
     Moreover, the housing portion that supports the first detent geometry can be a housing lid that axially closes the housing. Alternatively, or additionally, the housing portion that supports the second detent geometry can be a housing lid that axially doses the housing. In this context, axial dosing does not preclude the presence of a defined opening, the shaft portion extending through the latter, for example. Such a configuration has the effect that the rotation limitation module can be constructed from comparatively few components. 
     A steering wheel module of the type mentioned at the outset is also disclosed, in which the rotation limitation module is embodied as a rotation limitation module according to the disclosure. By virtue of the fact that the rotation limitation module is of simple and compact construction, the steering wheel module overall is also of simple and compact construction. Moreover, a steering wheel module of this type can be operated while emitting comparatively little noise. 
     Furthermore, the effects and advantages discussed in the context of the rotation limitation module according to the disclosure also apply to the steering wheel module according to the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The disclosure will be explained hereunder by various exemplary arrangements that are shown in the appended drawings, in which: 
         FIG.  1    shows a steering wheel module according to the disclosure, having a rotation limitation module according to the disclosure and according to a first exemplary arrangement, in a longitudinal sectional illustration, 
         FIG.  2    shows the steering wheel module from  FIG.  1    in a sectional view along the plane II-II in  FIG.  1   , 
         FIG.  3    shows a steering wheel module according to the disclosure having a rotation limitation module according to the disclosure and according to a second exemplary arrangement, in a longitudinal sectional illustration, 
         FIG.  4    shows a steering wheel module according to the disclosure having a rotation limitation module according to the disclosure and according to a third exemplary arrangement, in a longitudinal sectional illustration, 
         FIG.  5    shows the steering wheel module from  FIG.  4    in a lateral view, 
         FIG.  6    shows the steering wheel module from  FIGS.  4  and  5    in a view along the direction VI in  FIG.  5   , 
         FIG.  7    shows a housing casing part of the rotation limitation module from  FIGS.  4  to  6    in a stand-alone illustration in a view along the direction VII from  FIG.  8   , 
         FIG.  8    shows the housing casing part from  FIG.  7    in a view along the direction VIII from  FIG.  7   , 
         FIG.  9    shows a second housing portion of the rotation limitation module from  FIGS.  4  to  6   , said second housing portion being embodied as a housing lid, in a stand-alone illustration, 
         FIG.  10    shows a first housing portion of the rotation limitation module from  FIGS.  4  to  6   , said first housing portion being embodied as a housing lid, in a stand-alone illustration, 
         FIG.  11    shows a sub-module of the rotation limitation module from  FIGS.  4  to  6   , which comprises the second housing portion from  FIG.  9    and the housing casing part from  FIGS.  7  and  8   , 
         FIG.  12    shows a sub-module of the rotation limitation module from  FIGS.  4  to  6   , which comprises the first housing portion from  FIG.  10    and the housing casing part from  FIGS.  7  and  8   , 
         FIG.  13    shows an alternative sliding guide which can be used in combination with all above-mentioned exemplary arrangements of the rotation limitation module, 
         FIG.  14    shows a view of the sliding guide from  FIG.  13    along the direction XIV from  FIG.  13   , and 
         FIG.  15    shows a perspective sectional view through a steering module according to the disclosure, in which the housing is friction-welded. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    shows a steering wheel module  10  for a steer-by-wire steering system. 
     The steering wheel module  10  comprises a steering wheel  12  which is only schematically illustrated and is fastened to a first end of a steering wheel shaft  14 , and a rotation limitation module  16  according to a first exemplary arrangement, which is provided on a second end of the steering wheel shaft  14  that faces away from the steering wheel  12 . 
     The steering wheel  12 , conjointly with the steering wheel shaft  14 , is rotatable about a central axis  18 . 
     The task of the rotation limitation module  16  lies in limiting a rotation of the steering wheel  12  and of the steering wheel shaft  14  connected to the former in both directions. 
     To this end, the rotation limitation module  16  has a housing  20  in which a shaft portion  14   a  of the steering wheel shaft  14  is received. 
     Furthermore provided is a limiter disk  22 . 
     The latter is coupled in a rotationally fixed manner to the shaft portion  14   a  by way of a sliding guide  24 . The limiter disk  22  can thus be displaced along the central axis  18  in relation to the shaft portion  14   a , but cannot be rotated in relation to the shaft portion  14   a.    
     In the exemplary arrangement illustrated, the sliding guide  24  on the shaft comprises a total of four bevels  24   a ,  24   b ,  24   c ,  24   d . An opening  26 , which is provided in the limiter disk  22  and into which the shaft portion  14   a  is inserted, is designed in a complementary manner. 
     The limiter disk  22  on the external circumference thereof moreover has an external thread  28  which is driven into an internal thread  30  provided on an internal circumference of the housing  20 . 
     Both the external thread  28  and the internal thread  30  run completely in a circumferential manner. 
     Furthermore, the internal thread  30  extends substantially across the entire axial length of the housing  20 . 
     The two threads in the exemplary arrangement illustrated are metric threads of the size M60. An associated thread pitch is 1 mm or 1.5 mm. These values are examples. 
     If the shaft portion  14   a  is rotated by virtue of an activation of the steering wheel  12 , the limiter disk  22  is thus repositioned in the axial direction. 
     In order for a rotation in a first rotation direction D 1  to be limited, an axial protrusion  36 , substantially in the shape of an angular segment, is provided on a housing portion  32 , the latter delimiting the housing  20  in a first axial direction R 1  and in the exemplary arrangement illustrated being embodied so as to be integral to a housing casing part  34  (see also  FIG.  2   ). 
     The axial protrusion  36  is produced so as to be integral to the housing portion  32 . 
     Furthermore, the axial protrusion  36  points into the interior of the housing  20 . 
     The axial protrusion  36  here extends substantially across 10 angular degrees. 
     Moreover, said axial protrusion  36  has a length of approx. 10 mm measured in the radial direction. 
     Said axial protrusion  36  has a height measured in the axial direction of approx. 1 mm. 
     Moreover, a circumferential face of the axial protrusion  36  that points counter to the rotation direction D 1  to be limited is configured as a detent geometry  38  which in the exemplary arrangement illustrated is a substantially flat detent face  39 . 
     In order fora rotation of the shaft portion  14   a  in a second rotation direction D 2 , counter to the first rotation direction D 1 , to be limited, a second axial protrusion  42  is provided on a housing portion  40  that delimits the housing  20  in a second axial direction R 2 . 
     The second axial direction R 2  here is counter to the first axial direction R 1 . 
     The housing portion  40  along the central axis  18  is thus opposite the housing portion  32 . 
     In the exemplary arrangement illustrated, the housing portion  40  is embodied as a housing lid  41  that axially closes the housing  20 , and the axial protrusion  42  is provided so as to be integral to the housing lid  41 . 
     The second axial protrusion  42  is also substantially in the shape of an angular segment. The design of said second axial protrusion  42  here corresponds to the design of the first axial protrusion  36 . 
     The axial protrusion  36  thus likewise points into the interior of the housing  20 . 
     Said axial protrusion  36  also extends substantially across 10 angular degrees. 
     Furthermore, said axial protrusion  36  has a length of approx. 10 mm measured in the radial direction. 
     The height of said axial protrusion  36  measured in the axial direction is approx. 1 mm. 
     A detent geometry  44 , which in the exemplary arrangement illustrated is a substantially flat detent face  45 , is moreover configured on a circumferential face of the axial protrusion  42  that points counter to the second rotation direction D 2  to be limited. 
     The detailed design of the axial protrusions  36 ,  42  and of the detent faces  39 ,  45  provided on the latter is also apparent in  FIGS.  9  to  12   . These figures are however directed toward another embodiment of the rotation limitation module  16 , but there are no differences in terms of the design of the axial protrusions  36 ,  42 . 
     A further axial protrusion  46  is provided on a side of the limiter disk  22  that faces the first detent geometry  38 . 
     In one exemplary arrangement, the axial protrusion  46  is embodied so as to be integral to the limiter disk  22 . 
     Like the axial protrusions  36 ,  42  already explained, the axial protrusion  46  is also substantially in the shape of an angular segment. The design of said axial protrusion  46  here corresponds to the design of the axial protrusions  36  and  42 . 
     The axial protrusion  46  thus also extends substantially across 10 angular degrees. 
     Furthermore, said axial protrusion  46  has a length of approx. 10 mm measured in the radial direction. 
     The height of said axial protrusion  46  measured in the axial direction is approx. 1 mm. 
     A first counter-detent geometry  48 , which in the exemplary arrangement illustrated is a substantially flat detent face  50 , is moreover configured on a circumferential face of the axial protrusion  46  that points in the direction of the rotation direction D 1  to be limited. 
     The first counter-detent geometry  48 , for limiting a rotation of the shaft portion  14   a  in the first rotation direction D 1 , is configured for contacting the first detent geometry  38 . 
     In other words, the detent faces  39  and  50  are configured for contacting each other when the limiter disk  22 , by virtue of a rotation of the shaft portion  14   a , moves to the right in  FIG.  1   . In this case, the detent faces  39  and  50  come to bear on each other in a planar manner. 
     It is understood here that both detent faces  39 ,  50  are oriented in the circumferential direction, i.e. that a respective surface normal points in the circumferential direction. The detent faces  39 ,  50  per se thus extend in the axial direction and the radial direction. 
     An axial protrusion  52  is also provided on a side of the limiter disk  22  that faces the second detent geometry  44 . 
     In one exemplary arrangement, the axial protrusion  52  is likewise embodied so as to be integral to the limiter disk  22 . 
     The design of said axial protrusion  52  here corresponds to the design of the axial protrusion  46 . Furthermore, the axial protrusion  52  along the central axis  18  lies exactly opposite the axial protrusion  46 . 
     Said axial protrusion  52  thus also extends substantially across 10 angular degrees. 
     Furthermore, said axial protrusion  52  has a length of approx, 10 mm measured in the radial direction. 
     The height of said axial protrusion  52  measured in the axial direction is approx. 1 mm. 
     A second counter-detent geometry  58 , which in the exemplary arrangement illustrated is a substantially flat detent face  60 , is moreover configured on a circumferential face of the axial protrusion  52  that points in the direction of the rotation direction to be limited. 
     The second counter-detent geometry  58 , for limiting a rotation of the shaft portion  14   a  in the second rotation direction D 2 , is configured for contacting the second detent geometry  44 . 
     In other words, the detent faces  45  and  60  are configured for contacting each other when the limiter disk  22 , by virtue of a rotation of the shaft portion  14   a , moves to the left in  FIG.  1   . In this instance, the detent faces  45  and  60  come to bear on each other in a planar manner. 
     The two detent faces  45 ,  60  are also oriented in the circumferential direction, i.e. a respective surface normal points in the circumferential direction. The faces per se thus extend in the axial direction and the radial direction. 
     The detailed design of the axial protrusions  46 ,  52  and of the detent faces  50 ,  60  provided thereon is also apparent in  FIGS.  13  to  14   . The limiter disk  22  shown in these figures here differs from the limiter disk  22  of the rotation limitation module  16  according to the first exemplary arrangement only in terms of the sliding guide  24 . There are thus no differences in terms of the design of the axial protrusions  46 ,  52 . 
     The limiter disk  22  in  FIG.  1    is illustrated in a central position which is distinguished in that a first axial spacing A 1 , between the limiter disk  22  and the housing portion  32  that supports the first detent geometry  38 , and a second axial spacing A 2 , between the limiter disk  22  and the housing portion  40  that supports the second detent geometry  44 , are identical. 
     As is evident in  FIG.  1   , the axial spacings A 1 , A 2  are measured so as to proceed from the axial end faces of the axial protrusions  36 ,  46 ,  42 ,  52 . The smallest spacing between the limiter disk  22  and the assigned housing portions  32 ,  40  is thus relevant. 
     The central position of the limiter disk  22  preferably also corresponds to a central position of the steering wheel  12 , which corresponds to an assigned vehicle traveling straight ahead. 
     A measure by which the shaft portion  14   a  can be rotated in the first rotation direction D 1  is thus the sum of an angle of rotation which is required to overcome the spacing A 1  and of an angle of rotation which the axial protrusion  46  upon overcoming the axial spacing A 1 , in a state plunged into the housing portion  32  so to speak, can still perform before the detent faces  39  and  50  contact each other. 
     The same applies to the second rotation direction D 2 . 
     A measure by which the shaft portion  14   a  can be rotated in the second rotation direction accordingly is the sum of an angle of rotation that is required to overcome the axial spacing A 2  and of an angle of rotation that the axial protrusion  52  upon overcoming the spacing A 2 , in a state plunged into the housing portion  40  so to speak, can perform before the detent faces  45  and  60  contact each other. 
     Consequently, an angle of rotation permitted by the rotation limitation module  16  can be adjusted by selecting the size of the axial spacings A 1 , A 2 , on the one hand, and by selecting the respective angle of rotation in the plunged state, on the other hand. 
     The axial spacings A 1  and A 2  here can be adjusted by the axial relative positioning of the limiter disk  22  in relation to the housing portions  32 ,  40 . 
     The angles of rotation in the plunged state are a function of a relative rotary position of the detent face  39  in relation to the detent face  50 , and of the detent face  45  in relation to the detent face  60 , this being present in a situation in which the respectively relevant axial spacing A 1 , A 2  is zero. 
     This rotary position can be adjusted by a suitable rotary positioning of the housing portions  32 ,  40 . 
     The housing portion  32  in the exemplary arrangement illustrated here is embodied so as to be integral to the housing casing part  34  such that no relative movement between the housing portion  32  and the housing casing part  34  is possible in this context. However, the housing portion  40 , which is embodied as a housing lid  41 , can be established in a suitable rotary position on the housing casing part  34 . 
     The pitch of the external thread  28  and of the internal thread  30  is relevant when an angle of rotation of the shaft portion  14   a  is converted into an axial displacement of the limiter disk  22 . 
     In the exemplary arrangement illustrated, the rotation limitation module  16  is configured such that, when viewed in the radial direction, the first axial spacing A 1  and the second axial spacing A 2  in cumulative terms correspond to a pitch of the external thread  28  of the limiter disk  22 . 
     Proceeding from a central position, the shaft portion  14   a  can thus be rotated by in each case half a revolution in both directions until the respective axial protrusion  46 ,  52  begins to plunge into the respectively assigned housing portion  32 ,  40 . 
     Furthermore, the detent faces  39 ,  50  and  45 ,  60  in rotary terms are in each case positioned relative to one another in such a way that a rotation of approx. 270° is still possible once plunging has taken place. 
     Such a rotation limitation module  16  overall thus limits a rotation to in each case approx. 450° i.e. 125 revolutions, in both directions. 
     It is understood here that the dimensional specifications mentioned above, either spacings or angles, serve only for easier explanation and on no account are to be considered limiting. 
     In one variant of the first exemplary arrangement, the housing portion  32  is not embodied so as to be integral to the housing casing part  34  but is likewise implemented by a housing lid that axially delimits the housing  20 . 
     In this context, such a housing lid may be connected to the housing casing part  34  by friction welding to a precise angle, this yet to be explained later in connection with  FIG.  15   . 
     In order for the impacting action of the detent faces  39 ,  50  and  45 ,  60  to be damped, at least an axial end side of the limiter disk  22 , or an axial end side of the housing portion  32  that supports the first detent geometry  38 , or an axial end side of the second housing portion  40  that supports the second detent geometry  44 , at least in portions can moreover be covered with an elastically deformable shock-absorbent material  61 . In this context, a shock-absorbent material  61  of this type, which is compressed in the axial direction before the detent faces  39 ,  50  impact each other, is plotted in a purely exemplary manner in  FIG.  2   . 
     Shown in  FIG.  3    is a steering wheel module  10  in which the rotation limitation module  16  is designed according to a second exemplary arrangement. 
     Only the points of differentiation in comparison to the first exemplary arrangement will be discussed here. Identical or functionally equivalent components have the same reference signs. 
     The second exemplary arrangement differs from the first exemplary arrangement only in terms of the housing portion  32 . 
     In the second exemplary arrangement here, the housing portion  32  is embodied as a housing lid  33  that axially delimits the housing  20 . 
     In order for the housing lid  33  to be held on the housing casing part  34 , the axial peripheral region  62  of the latter is folded radially inward. 
     Moreover, the housing lid  33  in rotary terms is positioned on the housing casing part  34  by a pin  64  such that the adjustment possibilities in terms of the permissible angle of rotation explained in detail above continue to be maintained. 
     A steering wheel module  10  having a rotation limitation module  16  according to a third exemplary arrangement is illustrated in  FIGS.  4  to  12   . 
     Only the points of differentiation in comparison to the first exemplary arrangement will again be discussed. Identical or functionally equivalent components are again provided with the same reference signs. 
     In the rotation limitation module  16  according to the third exemplary arrangement, the first housing portion  32  and the second housing portion  40  are in each case embodied as a housing lid  33 ,  41  that delimits the housing  20  in the axial direction. 
     In order to be able to position the housing lid  33  at a precise angle on the housing casing part  34 , said housing lid  33  is provided with positioning cams  66  which project in a substantially radial manner (see in particular  FIG.  10   ). 
     To this end, complementary depressions  68  are configured on the housing casing part  34 . 
     In this way, the housing lid  33  is always assembled on the housing casing part  34  in such a way that the positioning cams  66  engage in each case in an assigned depression  68 . 
     In the exemplary arrangement illustrated, the housing lid  33  has a total of twelve positioning cams  66  such that an angular pattern of 30° results. 
     Positioning cams  72 , which, however, extend substantially in the axial direction, are likewise formed on the housing lid  41 . Depressions  74 , which are formed on a shoulder  76 , are assigned to said positioning cams  72  on the housing casing part  34 . 
     The housing lid  41  is thus always positioned on the housing casing part  34  in such a way that each of the positioning cams  72  engages in an assigned depression  74 . 
     A total of twelve positioning cams  72  are also provided on the housing lid  41  such that an angular pattern of 30° results again. 
     The previously explained angles of rotation of the shaft portion  14   a  made possible in the first rotation direction D 1  and the second rotation direction D 2 , for example in terms of those proportions of angles of rotation that are still possible after the plunging of the axial protrusions  46 ,  52 , can thus be adjusted by positioning the housing lids  33 ,  41  in terms of rotation by the positioning cams  66 ,  72 . 
     The housing  20  of the rotation limitation module  16  thus adjusted is then placed onto a housing  78  of the steering wheel module  10  and fastened thereto by means of a holding plate  80 . 
     In the exemplary arrangement illustrated, the holding plate  80  is fixed to the housing  78  by a plurality of screws  82 . 
     An alternative exemplary arrangement of the sliding guide  24  is shown in  FIGS.  13  and  14   . 
     Instead of the bevels  24   a ,  24   b ,  24   c ,  24   d  (cf.  FIG.  2    an axial toothing  84  is provided on the shaft portion  14   a . The opening  26  on the limiter disk  22  is provided with grooves  86  which are configured and disposed in a manner complementary to said axial toothing  84 . In this way, the limiter disk  22  can also be connected in a rotationally fixed manner to the shaft portion  14   a  and at the same time remain axially displaceable. 
     An exemplary arrangement in which the housing lids  33 ,  41  are configured as disks, which are fastened to the housing casing part  34  by friction welding, is shown in  FIG.  15   . These components can thus be designed and assembled in a very simple and cost-effective manner, and do not have any radial toothings. The compactness is also highly distinctive in this variant. Assembling here can also very easily take place in an automated manner. 
     The welded locations are provided on the two opposite end sides of the housing casing part  34 . 
     The housing lids  23 ,  31  and the limiter disk  22  can be produced from a cold-formed strip of sheet metal, this representing one option. 
     The housing lids  23 ,  31  may have contours which simplify and improve assembling, on the one hand, and friction welding, on the other hand. 
     The rotating procedure during friction welding has to be terminated in a targeted manner, and it has to be achieved specifically that the axial protrusions  36 ,  46  are at the correct circumferential position in relation to the threads, since said axial protrusions  36 ,  46  define the terminal detent. 
     Insulation seals, which can act as terminal detent dampers between the end sides of the axial protrusions  36 ,  46  and  42 ,  52 , can be additionally provided. 
     The central opening shown in the housing lid  33  can also be omitted, this preventing an ingress of dirt.