Patent Publication Number: US-2023135320-A1

Title: Rotation-limiting assembly and steering wheel assembly for a steer-by-wire steering system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to German Priority Application No. 102021212302.3, filed Nov. 2, 2021, the disclosure of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The disclosure relates to a rotation-limiting assembly for a steer-by-wire steering system, having a housing, in which a shaft portion rotatable about a center axis, is accommodated and can be coupled rotationally to a steering wheel shaft or is designed as a portion of the steering wheel shaft. 
     BACKGROUND 
     Rotation-limiting assemblies are customarily configured in such a manner that, when the maximally permitted angle of rotation is reached, the shaft portion runs against a comparatively hard stop and can no longer be further rotated. This striking action may surprise a driver of the vehicle provided with the rotation-limiting assembly and may therefore be perceived to be uncomfortable. The driver does not have any possibility of getting ready for imminently reaching the maximally permitted angle of rotation. 
     SUMMARY 
     The disclosure describes a rotation-limiting assembly, in which the shaft portion is coupled to the housing via a threaded pair, comprises an external thread and an internal thread screwed into the external thread, a sliding guide with a sliding guide external contour and a sliding guide internal contour, and a force fit. Instead of the force fit, a further sliding guide may also be provided. The threaded pair, the sliding guide, and the force fit or the further sliding guide are arranged sequentially in the radial direction. If a force fit is provided, the latter couples the shaft portion to the housing in such a manner that, when a predefined breakaway torque is exceeded, the shaft portion is rotatable in relation to the housing. In addition, a first stop disk is provided on the shaft portion on a first axial side of the sliding guide external contour and a second stop disk is provided on the shaft portion on a second axial side which is opposed to the first axial side. The first stop disk and the second stop disk are designed to make contact with a component carrying the sliding guide internal contour, in order to limit a rotational movement of the shaft portion. In this connection, the sequential arrangement of the threaded pair, the sliding guide, and the force fit or the further sliding guide does not imply any order whatsoever. The threaded pair, the sliding guide, and the force fit or the further sliding guide can therefore be arranged in any order along a radial direction of flow of force or torque. 
     The threaded pair serves to convert a rotational movement of the shaft portion into a translational movement. The translational movement takes place along the center axis, i.e. axially. The sliding guide serves to support the torque introduced by rotation of the shaft portion and to ensure movability in the axial direction. Depending on the direction of rotation, after overcoming a predetermined axial distance which corresponds to a maximally permissible angle of rotation of the shaft portion, the component carrying the sliding guide internal contour therefore makes contact with the first stop disk or the second stop disk. Rotation of the shaft portion is thereby reliably limited. If the shaft portion is coupled to the housing via the force fit, even in the event of making contact with the respective stop disk the shaft portion can be rotated further in relation to the housing if the breakaway torque is exceeded. If the shaft portion is coupled to the housing via the further sliding guide, a further displacement relative to the housing can take place. From the view of a user of the rotation-limiting assembly, rotation of the steering wheel is therefore not limited by a hard stop. On the contrary, after contact is made with the first stop disk or the second stop disk, the user feels a significantly increased resistance on operating the steering wheel. This may cause the user not to rotate the steering wheel further. Overall, a high degree of comfort for the operation of the rotation-limiting assembly is produced. The rotation-limiting assembly comprises few components and is therefore constructed structurally simply and compactly. Owing to the fact that sliding guides, force fits, and threaded pairs can easily be produced by conventional methods and systems, the rotation-limiting assembly can also be produced cost-effectively. 
     The sliding guide comprises, for example, a toothing running solely in the axial direction. It is also possible to realize the sliding guide by flattened portions provided on the shaft portion. 
     In another exemplary arrangement, the sliding guide external contour is provided on the external circumference of a first sliding guide sleeve that is fastened on the shaft portion via the force fit such that, when a predefined breakaway torque is exceeded, the first sliding guide sleeve is rotatable in relation to the shaft portion. 
     The component carrying the sliding guide internal contour can likewise be a sleeve-shaped component, on the internal circumference of which the sliding guide internal contour is provided. This component can be referred to as a second sliding guide sleeve. 
     In a further exemplary arrangement, an internally threaded sleeve is provided which, on its internal circumference, has an internal thread that cooperates with an external thread provided on the component carrying the sliding guide internal contour, wherein the internally threaded sleeve is fastened to the housing via the force fit such that, when a predefined breakaway torque is exceeded, the internally threaded sleeve is rotatable in relation to the housing. In another example, the internally threaded sleeve is coupled non-rotatably, but axially displaceably, to the housing via the further sliding guide. Furthermore, the internally threaded sleeve has a compact design, and therefore the rotation-limiting assembly can be installed as a whole in a small construction space. Compared to the previously mentioned arrangement, there is moreover the advantage that a torque that has to be introduced into the threaded pair from the shaft portion does not pass via the force fit in a situation in which the predefined breakaway torque is not exceeded. 
     The first sliding guide sleeve can be fastened to the shaft portion via a force-fitting ring arranged radially between the first sliding guide sleeve and the shaft portion. In another example, the internally threaded sleeve can be fastened to the housing via a force-fitting ring arranged radially between the internally threaded sleeve and the housing. A force-fitting ring here is an annular component that can be arranged in an annular gap between two components to be coupled to each other. The force-fitting ring couples these two components in a force-fitting or frictionally locking manner. Furthermore, the force-fitting ring has the property that it acts with respectively predefined friction forces on the components to be coupled. A breakaway torque can therefore be set precisely. 
     The force-fitting ring is formed as a punched and bent part. The force-fitting ring can be produced from sheet metal. As a rule, they have a multiplicity of tabs or convexities which can each be applied under a predefined stress to the associated components. A breakaway torque can thereby be set with a comparatively high degree of accuracy. 
     According to one exemplary arrangement, at least one holding disk that is spring-loaded in the axial direction lies under prestress in the axial direction on the first sliding guide sleeve such that the first sliding guide sleeve is fastened to the shaft portion by the holding disk via the force fit. In another example, the at least one holding disk that is spring-loaded in the axial direction lies under prestress in the axial direction on the internally threaded sleeve such that the internally threaded sleeve is fastened to the housing by the holding disk via the force fit. In the first case, the holding disk can be coupled non-rotatably but axially displaceably to the shaft portion. In the second case, the holding disk can be coupled non-rotatably, but axially displaceably to the housing. An associated breakaway torque can be set in a simple manner by a corresponding prestress in the axial direction being selected. In order to produce the prestress, use can be made, for example, of a spring device. Overall, a simple design of the rotation-limiting assembly is produced. 
     Such a holding disk may be, but does not have to be, used in combination with a force-fitting ring. It is therefore conceivable for the force fit within the rotation-limiting assembly to be realized by a holding disk. It is likewise possible, as already explained, for the force fit to be brought about by a force-fitting ring, i.e. without a holding disk. Furthermore, it is conceivable to use both a force-fitting ring and a holding disk for generating the force fit. In this case, the force fit is in each case provided partly by the holding disk and partly by the force-fitting ring. 
     The holding disk can act as a stop disk. Such a holding disk therefore has a further function in addition to realizing the force fit. In other words, a single part constituting both a stop disk and a holding disk is provided. This results overall in a compact design of the rotation-limiting assembly. 
     The internally threaded sleeve can be coupled to the housing via a rotation-limiting mechanism such that, even when the breakaway torque is exceeded, the internally threaded sleeve is rotatable only to a limited extent in relation to the housing. In another example, the first sliding guide sleeve can be coupled to the shaft portion via a rotation-limiting mechanism such that, even when the breakaway torque is exceeded, the first sliding guide sleeve is rotatable only to a limited extent in relation to the shaft portion. In this way, an undesirably large relative rotation between the shaft portion and the housing may be avoided. During the operation of such a rotation-limiting assembly, a user therefore feels an increased resistance while rotating the steering wheel, the resistance implying that the breakaway torque of the force fit and a resultantly released rotatability is exceeded. The user therefore feels that a maximum angle of rotation will be imminently reached. After a certain further relative rotation, the rotation-limiting mechanism limits any further relative rotation. This is then no longer surprising for the user. 
     It is possible here for the rotation-limiting mechanism to comprise a pin that engages in a groove extending in the circumferential direction or in an elongated hole extending in the circumferential direction. A direction of extent of the groove or of the elongated hole is understood in each case as meaning the associated longitudinal direction, Such a rotation-limiting mechanism is constructed structurally simply and is reliable in operation. 
     According to one example, at least one of the stop disks is formed integrally with the shaft portion. In particular, such a stop disk is designed as a shaft shoulder. This results in a simple design of the rotation-limiting assembly. 
     When viewed in the radial direction, a first axial distance between the first stop disk and the component carrying the sliding guide internal contour and a second axial distance between the second stop disk and the component carrying the sliding guide internal contour can be cumulatively greater than or equal to two times a pitch of the internal thread. The first axial distance and the second axial distance can be cumulatively greater than or equal to three times a pitch of the internal thread. As discussed herein, a rotational movement of the shaft portion is converted by the threaded pair into an axial movement of the component carrying the sliding guide internal contour. It is therefore possible to set a maximally permitted angle of rotation of the shaft portion in a first direction of rotation via the first axial distance and a maximally permitted angle of rotation of the shaft portion in a second direction of rotation, which is opposed to the first direction of rotation, via the second axial distance. A rotational movement of the shaft portion can be converted here via the thread pitch into an axial movement of the component carrying the sliding guide internal contour. It goes without saying that a pitch of the internal thread and of the external thread meshing therewith can be the same. A pitch of a thread is understood here as meaning the axial distance that is covered by one revolution. This is synonymous with an axial distance between two thread tips. The pitch of a thread is sometimes also referred to as a lead. In the event that the cumulative axial distance is two times a pitch of the internal thread, the thread portion can be rotated from a rotational position, which corresponds to a center position, by 360° in both directions before the component carrying the sliding guide internal contour makes contact with the corresponding stop disk. In the event that the cumulative distance is three times a pitch of the internal thread, the shaft portion can be rotated from the center position by 540° in each direction. 
     The steering wheel assembly provides high operating comfort since a user is not surprised by a limitation of a rotation of the steering wheel and of the steering wheel shaft coupled thereto. 
     Furthermore, the effects and advantages explained in respect of the rotation-limiting assembly according to the disclosure also apply to the steering wheel assembly according to the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The disclosure is explained below with reference to various exemplary arrangements, which are shown in the attached drawings, in which: 
         FIG.  1    shows a steering wheel assembly according to the disclosure with a rotation-limiting assembly according to the disclosure according to a first exemplary arrangement in a center position, 
         FIG.  2    shows the steering wheel assembly from  FIG.  1   , the rotation-limiting assembly assuming a first stop position, 
         FIG.  3    shows the steering wheel assembly from  FIGS.  1  and  2   , the rotation-limiting assembly assuming a second stop position, 
         FIG.  4    shows a force-fitting ring, which is designed as a tolerance ring of the rotation-limiting assembly from  FIGS.  1  to  3    in an isolated illustration, 
         FIG.  5    shows a steering wheel assembly according to the disclosure with a rotation-limiting assembly according to the disclosure according to a second exemplary arrangement, 
         FIG.  6    shows a steering wheel assembly according to the disclosure with a rotation-limiting assembly according to the disclosure according to a third exemplary arrangement, 
         FIG.  7    shows a steering wheel assembly according to the disclosure with a rotation-limiting assembly according to the disclosure according to a fourth exemplary arrangement, 
         FIG.  8    shows a steering wheel assembly according to the disclosure with a rotation-limiting assembly according to the disclosure according to a fifth exemplary arrangement in a center position, 
         FIG.  9    shows the steering wheel assembly from  FIG.  8   , the rotation-limiting assembly assuming a stop position, 
         FIG.  10    shows the steering wheel assembly from  FIGS.  8  and  9   , the rotation-limiting assembly being moved beyond the stop position, and 
         FIG.  11    shows a steering wheel assembly according to the disclosure with a rotation-limiting assembly according to the disclosure according to a sixth exemplary arrangement. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosure is directed toward a steering wheel assembly for a steer-by-wire steering system, which comprises a steering wheel fastened to a first end of a steering wheel shaft, and a rotation-limiting assembly, wherein the rotation-limiting assembly is provided at a second end of the steering wheel shaft, which end faces away from the steering wheel. 
     Sometimes, the components of steering wheel assemblies are also referred to as a handwheel actuator or as a torque feedback unit. However, these terms may not include the steering wheel. In some instances, steering wheel assemblies are designed, inter alia, to generate a torque that provides the driver with mechanical feedback in the form of a restoring moment. 
     Rotation-limiting assemblies are sometimes also referred to as a mechanical torque limiter, with the aim here being for the introduction of a torque into the steering wheel assembly by operation of the steering wheel to be limited. Accordingly, rotation-limiting assemblies are used in steer-by-wire steering systems in order to limit a rotation of the steering wheel in both directions of rotation. Thus, the wiring for electrical systems that are arranged in the steering wheel are not damaged. Customarily, rotation-limiting assemblies are configured in such a manner that they permit rotation of the steering wheel by, for example, 540°, i.e. 1.5 revolutions, in both directions. In addition, for safety reasons, rotation-limiting assemblies have to be designed in such a manner that they function even if a power supply fails. 
       FIG.  1    shows a steering wheel assembly  10  for a steer-by-wire steering system. 
     The steering wheel assembly  10  comprises a steering wheel  12 , illustrated schematically, that is fastened to a first end of a steering wheel shaft  14 , and a rotation-limiting assembly  16  according to a first exemplary arrangement, which is provided at a second end of the steering wheel shaft  14 , which end faces away from the steering wheel  12 . 
     The steering wheel  12  is rotatable together with the steering wheel shaft  14  about a center axis  18 . 
     The rotation-limiting assembly  16  can limit a rotation of the steering wheel  12  and of the steering wheel shaft  14 , which is connected thereto, in both directions. 
     The rotation-limiting assembly  16  has a housing  20  in which a shaft portion  14   a  of the steering wheel shaft  14  is accommodated. 
     Furthermore, a first sliding guide sleeve  22  is provided. 
     The latter, on its external circumference, carries a sliding guide external contour  24 . 
     On its internal circumference, the first sliding guide sleeve  22  is fastened on the shaft portion  14   a  by a force-fitting ring  26 , which is designed as a tolerance ring, via a force fit  28 , in more precise terms via a first force-fitting portion. 
     The force-fitting ring  26  is arranged radially between the first sliding guide sleeve  22  and the shaft portion  14   a.    
     The rotation-limiting assembly  16  also comprises a second sliding guide sleeve  30 . 
     The second sliding guide sleeve  30  has, on its internal circumference, a sliding guide internal contour  32  that engages in the sliding guide external contour  24 . 
     The sliding guide internal contour  32  and the sliding guide external contour  24  therefore form a sliding guide  34 . 
     Generally, the second sliding guide sleeve  30  is a component  35  carrying the sliding guide internal contour  32 . 
     On its external circumference, the second sliding guide sleeve  30  has an external thread  36 . The latter cooperates with an internal thread  38  that is provided on the housing  20 . 
     The external thread  36  and the internal thread  38  therefore form a threaded pair  39 . 
     In the example arrangement illustrated, the sliding guide internal contour  32  and the sliding guide external contour  24  are designed as axial toothings. 
     The second sliding guide sleeve  30  is therefore held non-rotatably on the first sliding guide sleeve  22 , but so as to be displaceable axially in relation thereto. 
     Owing to the threaded pair  39 , the second sliding guide sleeve  30  can be rotated in relation to the housing  20 . 
     The shaft portion  14   a  is therefore coupled to the housing  20  via the threaded pair  39 , the sliding guide  34  and the force fit  28 . The threaded pair  39 , the sliding guide  34  and the force fit  28  are arranged sequentially in the radial direction here. 
     The force fit  28  is designed in such a manner that, when a predefined breakaway torque is exceeded, the shaft portion  14   a  can be rotated in relation to the housing  20 . In other words, the force-fitting ring  26  can slip through as soon as the shaft portion  14   a  is loaded with a torque, which exceeds the breakaway torque, relative to the housing  20 . 
     For example, when the predefined breakaway torque is exceeded, the first sliding guide sleeve  22  is therefore rotatable in relation to the shaft portion  14   a.    
     Furthermore, a first stop disk  40  is provided on a first axial side of the sliding guide external contour  24 , i.e. on a first axial side of the first sliding guide sleeve  22 . 
     The first stop disk  40  is substantially in the shape of a circular disk, with the shaft portion  14   a  extending through a central opening in the first stop disk  40 . 
     A second stop disk  42  is provided on a second axial side of the sliding guide external contour  24 , which side is opposed to the first axial side. 
     The second stop disk  42  is therefore positioned on a side of the first sliding guide sleeve  22 , which side is opposed to the first stop disk  40 . 
     The second stop disk  42  is also substantially in the shape of a circular disk, with the shaft portion  14   a  again extending through a central opening in the second stop disk  42 . 
     On an axial side facing away from the first sliding guide sleeve  22 , the first stop disk  40  is placed against a shaft shoulder  14   b  via an O ring  44 . 
     In other words, the first stop disk  40  is clamped in the axial direction between the O ring  44  and the first sliding guide sleeve  22 . 
     In a corresponding manner, the second stop disk  42  lies via an O ring  46  on a thrust piece  48  that is fastened to an axial end of the shaft portion  14   a  by a screw  50 . 
     The second stop disk  42  is therefore clamped between the first sliding guide sleeve  22  and the O ring  46 . 
     When the stop disks  40 ,  42  are clamped and the O rings  44 ,  46  are compressed, the stop disks  40 ,  42  lie under prestress in the axial direction on the first sliding guide sleeve  22 . 
     The force fit  28  is therefore proportionally also brought about by contact of the stop disks  40 ,  42  against the first sliding guide sleeve  22 . 
     The stop disks  40 ,  42  therefore also act as holding disks  52 ,  54 . 
     Furthermore, the first stop disk  40  is designed to make contact with the second sliding guide sleeve  30  in order to limit a rotational movement of the shaft portion  14   a  in a first direction of rotation D 1 . 
     The second stop disk  42  is designed to make contact with the second sliding guide sleeve  30  in order to limit a rotational movement of the shaft portion  14   a  in a second direction of rotation D 2 . 
     In this connection, the rotation-limiting assembly  16  is configured in such a manner that, when viewed in the radial direction, a first axial distance A 1  between the first stop disk  40  and the second sliding guide sleeve  30  and a second axial distance A 2  between the second stop disk  42  and the second sliding guide sleeve  30  cumulatively correspond to two times a pitch of the internal thread  38 . 
       FIG.  1    illustrates the second sliding guide sleeve  30  of the rotation-limiting assembly  16  in a center position, and therefore the axial distances A 1  and A 2  can be identical in size. 
     If, proceeding therefrom, the steering wheel shaft  14  is rotated in the first direction of rotation D 1 , the second sliding guide sleeve  30  makes contact with the first stop disk  40  after a revolution of 360° (see  FIG.  2   ). 
     Proceeding from this situation, the shaft portion  14   a  can then only be rotated further relative to the housing  20  if the breakaway torque is exceeded. In this situation, a user of the steering wheel assembly  10  therefore can feel a significantly increased resistance during rotation of the steering wheel  12  coupled to the steering wheel shaft  14 . 
     The same applies if the steering wheel  12  and the steering wheel shaft  14 , which is coupled thereto, is rotated from the center position in the second direction of rotation D 2 . 
     Base on the effect of the threaded pair  39 , the second sliding guide sleeve  30  shifts in the axial direction and, after a revolution of 360°, strikes against the second stop disk  42 . Further rotation is then still possible, but the breakaway torque needs to be overcome. A user of the steering wheel assembly  10  therefore notices an increased rotational resistance. 
     It is understood the axial distances A 1 , A 2  can be selected depending on the application. For example, the axial distances A 1 , A 2  can also be selected in such a manner that they cumulatively amount to three times the pitch of the internal thread. The shaft portion  14   a  can then be rotated from the center position shown in  FIG.  1    by 1.5 revolutions in each direction before the second sliding guide sleeve  30  runs against a respectively associated stop disk  40 ,  42 . 
     In another exemplary arrangement, not illustrated specifically here, one thread direction of rotation of the threaded pair  39  can be designed in such a manner that, when the steering wheel  12  and the steering wheel shaft  14  that is coupled thereto are rotated from the center position in the first direction of rotation D 1 , the second sliding guide sleeve  30  shifts until it strikes against the second stop disk  42 , In this exemplary arrangement, when the steering wheel  12  and the steering wheel shaft  14  coupled thereto rotate from the center position in the second direction of rotation D 2 , the second sliding guide sleeve  30  would therefore ultimately strike against the first stop disk  40 . Whether the second sliding guide sleeve  30  therefore strikes against the first stop disk  40  or the second stop disk  42 , depending on the direction of rotation D 1  or D 2 , therefore also depends on the thread direction of rotation of the threaded pair  39 . 
       FIG.  4    shows the force-fitting ring  26 , which is in the form of a tolerance ring, in an isolated illustration. 
     It can be seen here that the force-fitting ring  26  is in the form of a punched and bent part made from sheet metal. On its external circumference, it has a multiplicity of convexities  55  that are compressed in a defined manner when the force-fitting ring  26  is arranged between the shaft portion  14   a  and the first sliding guide sleeve  22 . 
     A steering wheel assembly  10  with a rotation-limiting assembly  16  according to a second exemplary arrangement is illustrated in  FIG.  5   . 
     Only the difference in relation to the rotation-limiting assembly  16  according to the first exemplary arrangement is discussed here. Identical or mutually corresponding components are provided with the same reference signs. 
     In the present case, the differences concern the mounting and prestress of the stop disks  40 ,  42 , that are again also holding disks  52 ,  54 . 
     In comparison to the first exemplary arrangement, the O rings  44 ,  46  have now been omitted. The first stop disk  40  therefore lies on one side directly on the shaft shoulder  14   b  and on the other side directly on the first sliding guide sleeve  22 . 
     The second stop disk  42  also lies directly on the first sliding guide sleeve  22 . However, on the axial side of the second stop disk, which side faces away from the first sliding guide sleeve  22 , a disk spring  56  is provided via which the second stop disk  42  is prestressed in the axial direction by the thrust piece  48 . 
     In respect of its function and the remaining structure, the rotation-limiting assembly  16  according to the second exemplary arrangement corresponds to the first exemplary arrangement, and therefore reference can be made to the explanations above. 
     A steering wheel assembly  10  having a rotation-limiting assembly  16  according to a third exemplary arrangement is shown in  FIG.  6   . 
     Again, only the differences with regard to the exemplary arrangements that have already been explained will be discussed here. Identical or mutually corresponding components are provided with the same reference signs. 
     In contrast to the previously explained exemplary arrangements, the sliding guide external contour  24  is now provided directly on the shaft portion  14   a . The first sliding guide sleeve  22  is therefore dispensed with. 
     A further difference can comprise that an internally threaded sleeve  58  is now provided, the internal circumference of which is provided with an internal thread  60  that engages with an external thread  36  of the second sliding guide sleeve  30 . 
     The threaded pair  39  is therefore provided between the internally threaded sleeve  58  and the second sliding guide sleeve  30 . The internally threaded sleeve  58  is mounted here in the housing  20  via a force-fitting ring  62 , which is in the form of a tolerance ring. 
     The force-fitting ring  62  is now designed in such a manner that it brings about a force-fitting connection between the internally threaded sleeve  58  and the housing  20 , the connection being designed in such a manner that the internally threaded sleeve  58  can be rotated in relation to the housing  20  if a predetermined breakaway torque is exceeded. 
     The force-fitting ring  62  is illustrated in isolation in  FIG.  4   . 
     The force-fitting ring  62  is arranged radially between the internally threaded sleeve  58  and the housing  20 . 
     There are also differences in respect of the stop disks  40 ,  42 . 
     The first stop disk  40  is now formed integrally with the shaft portion  14   a . In other words, the first stop disk  40  is formed by the shaft shoulder  14   b.    
     The second stop disk  42  is fastened to the axial end of the shaft portion  14   a  by the screw  50 . The second stop disk  42  can also be considered to be a development of the thrust piece  48 . 
     The two stop disks  40 ,  42  are mounted rigidly in relation to the shaft portion  14   a.    
     The stop disks  40 ,  42  are now also no longer designed as holding disks. 
     The function of the rotation-limiting assembly according to  FIG.  6    is as in the previously explained exemplary arrangements. One difference is that, after the second sliding guide sleeve  30  has made contact with the first stop disk  40  or the second stop disk  42 , a relative rotation occurs between the internally threaded sleeve  58  and the housing  20 . This relative rotation replaces a relative rotation between the shaft portion  14   a  and the first sliding guide sleeve  22 . 
     A variant of the steering wheel assembly  10  having a rotation-limiting assembly according to the third exemplary arrangement is shown in  FIG.  7   . This variant is referred to as a fourth exemplary arrangement. 
     The difference in relation to the third exemplary arrangement can comprise that a rotation-limiting mechanism  64  is now provided. 
     In this case, the internally threaded sleeve  58  is coupled to the housing  20  via said rotation-limiting mechanism  64 , and therefore, even when the breakaway torque is exceeded, the internally threaded sleeve  58  is rotatable only to a limited extent in relation to the housing  20 . 
     The rotation-limiting mechanism  64  comprises a pin  66  that is mounted in an associated opening  68  on the housing  20 . The pin  66  is held immovably here on the housing  20 . 
     The pin  66  protrudes radially inward from the housing  20  and engages in an elongated hole  70  that is formed on the internally threaded sleeve  58  and extends in the circumferential direction. 
     The internally threaded sleeve  58  can therefore be rotated in relation to the housing  20  only to the extent that the pin  66  is displaceable relative to the elongated hole. As soon as the pin  66  strikes against an end of the elongated hole  70 , no further rotation is possible. 
     Furthermore, the explanations with regard to the third exemplary arrangement also apply to the fourth exemplary arrangement. 
     It is understood that the rotation-limiting mechanism  64  which is explained in connection with the fourth exemplary arrangement can readily also be used in the other exemplary arrangements. 
     For example, a variant of the first exemplary arrangement can be equipped with such a rotation-limiting mechanism  64  (not illustrated). In this case, the pin  66  is positioned in an associated opening  68  on the shaft portion  14   a  and interacts with an elongated hole  70  that is provided on the first sliding guide sleeve  22 . 
       FIGS.  8  to  10    illustrate a steering wheel assembly  10  having a rotation-limiting assembly  16  according to a fifth exemplary arrangement. 
     The fifth exemplary arrangement is a development of the third exemplary arrangement. As such, only the differences in relation to the third exemplary arrangement will be explained below. 
     As already mentioned, the stop disks  40 ,  42  are not holding disks in the fifth exemplary arrangement either. 
     However, holding disks  52 ,  54 , which are separated from the stop disks  40 ,  42 , are now provided. 
     The first holding disk  52  is placed here onto the internally threaded sleeve  58  under axial prestress that results from an axial compression of a spring element  72 . 
     The spring element  72  is held axially on the housing  20  by a securing ring  74 . 
     The second holding disk  54  is likewise placed onto the internally threaded sleeve  58  under axial prestress. The axial prestress results here from the compression of a spring element  76 . The latter is arranged between the second holding disk  54  and the housing  20 . 
     Both the spring element  72  and the spring element  76  are designed as elastomer springs. It is likewise conceivable to produce at least one of the spring elements  72 ,  76  from metal, for example in the form of a disk spring made from steel. 
     If the rotation-limiting assembly  16  according to the fifth exemplary arrangement is operated in such a manner that the second sliding guide sleeve  30  runs against the second stop disk  42  (see  FIG.  9   ), the internally threaded sleeve  58  can be moved in a direction away from the second stop disk  42 . The spring element  72  is compressed in the process. 
     If the spring element  72  cannot be compressed further, but, via the shaft portion  14   a , a torque is introduced that is greater than the breakaway torque of the force-fitting ring  62 , the internally threaded sleeve  58  can be rotated in relation to the housing  20  (see  FIG.  10   ). 
     The same applies (not illustrated) for a situation in which the second sliding guide sleeve  30  runs against the first stop disk  40 . 
     It is understood that the rotation-limiting assembly  16  according to the fifth exemplary arrangement can also be combined with a rotation-limiting mechanism  64  as has been described in conjunction with the rotation-limiting assembly  16  according to the fourth exemplary arrangement. However, care has to be taken to ensure that the elongated hole  70  is of such a width in the axial direction that it does not obstruct the previously descried axial shifting of the internally threaded sleeve  58 . 
       FIG.  11    shows a steering wheel assembly  10  having a rotation-limiting assembly  16  according to a sixth exemplary arrangement. 
     This exemplary arrangement is a development of the fifth exemplary arrangement from  FIGS.  8  to  10   , and therefore it is explained on this basis. 
     In comparison to the fifth exemplary arrangement, the force-fitting ring  62  is omitted. 
     The internally threaded sleeve  58  is now mounted on the housing  20  in an axially displaceable manner via a further sliding guide  78 , but non-rotatably. 
     If the second sliding guide sleeve  30  strikes against one of the stop disks  40 ,  42 , the shaft portion  14   b  can therefore now rotate further because the internally threaded sleeve  58  can be shifted axially under axial compression of the respectively associated spring element  72 ,  76 . 
     The holding disks  52 ,  54  accordingly serve merely for compressing the spring elements  72 ,  76 . 
     The rotation-limiting assembly  16  according to the sixth exemplary arrangement therefore manages without a force fit.