Rotation angle limiting unit for a steering system of a vehicle

Abstract

The invention relates to a rotation angle limiting unit (4) for a shaft (3) of a steering system (1) of a vehicle, the unit comprising: a first axial bearing ring (5) comprising a first bearing cage (6) and a first rolling element (7) guided in the first bearing cage (6); a first limiting element (8) which can be torque-transmittingly coupled to the shaft (3), surrounds the shaft (3), and forms a first raceway (9) for the first rolling element (7) and a first stop (10) for the first rolling element (7); and a second limiting element (11) which is torque-transmittingly connected to the surroundings (2) and forms a second raceway (12) and a second stop (13) for the first rolling element (7); characterised in that at least one of the stops (10, 13) protrudes from the raceway (9, 12) as an axial projection (14) and the corresponding limiting element or elements have a recess (16) axially adjacent to the axial projection on a side (15) facing away from the raceway (9, 12).

Description

[0001] Angle limiting unit for a steering system of a vehicle

[0002] The present invention relates to a rotation angle limiting unit for a steering system of a vehicle, in particular for the steering shaft of a handwheel actuator for a steer-by-wire steering system.

[0003] With steer-by-wire steering systems, the driver's steering command is not transmitted directly to the wheels mechanically via a steering gear. Instead, the steering command is detected by a sensor-equipped unit with which the driver interacts, then processed in a control unit, and transmitted to the wheels as a steering command via a servo drive in a steering actuator. This eliminates the immediate need for a steering wheel familiar from conventional steering systems, as any other means of detecting the driver's input can also be used. However, entering steering commands via a steering wheel has become established among drivers and will therefore largely be retained in the future, if only to avoid making the transition to a new type of steering system even more difficult.

[0004] In conventional steering systems, the steering wheel's rotation is limited by the steering angle that occurs at full wheel lock. Depending on the manufacturer's configuration, one and a half to two turns from the center position in either direction is a common value. With steer-by-wire steering systems, this limitation theoretically no longer exists. The characteristics of the resulting vehicle steering angle can be adjusted independently of the driver's steering angle, for example, depending on speed. Nevertheless, there is a need to mechanically limit the possible steering angle of the steering wheel and thus provide the driver with feedback that the maximum steering angle has been reached. Angle limiters are used for this purpose.

[0005] For example, DE 10 2019207 609 A1 discloses a mechanical angle limiter for a steer-by-wire steering system. In this angle limiter, the steering wheel's rotation is transmitted via rolling elements similar to an axial bearing. The rolling elements run in track-like grooves interrupted by stops. As soon as the rolling elements hit the stops, further rotation is inhibited. By connecting several stages in series, large angle ranges can also be achieved. A disadvantage of this design is the manufacturing of the grooves for the disc-shaped rolling elements. Such grooves, as recesses, are very difficult to produce in cost-effective large-scale production.

[0006] DE 10 2022 112 862 A1 proposes a ball-based angle limiter. Three balls are provided per stage, rolling in ball raceways recessed into the disc bodies, which is technically complex to manufacture. The raceways only cover a partial angular range; three rolling elements and thus three partial raceways per stage are proposed. Cage elements, as known from axial bearing technology, are provided to guide the balls in the circumferential direction, while guidance in the radial direction is provided by the raceways themselves. The end of each partial raceway then represents the end stop of the rotational movement. As soon as the ball hits the end of the raceway, it attempts to roll over the stop. This creates an axial force, which in turn must be absorbed between the steering shaft and the surrounding structure.Therefore, the design also includes additional stop elements between the individual discs to reduce the axial forces acting on the surrounding area and the shaft bearings. These additional stop elements increase manufacturing costs. Furthermore, several stages connected in series are provided to cover the required total rotation angle range.

[0007] It is the object of the invention to provide an improved angle of rotation limiter in which, in particular, the track elements can be manufactured cost-effectively and the required torques can be transmitted safely and without additional stop elements.

[0008] According to the invention, this object is achieved by a rotation angle limiting unit according to the preamble of claim 1, in which at least one stop for the first rolling element protrudes from the raceway as an axial projection and has a recess on a side facing away from the raceway. The invention is based on a basic arrangement in which a first limiting element is torque-proof connected to the shaft whose rotation angle is to be limited. Limiting elements within the meaning of the invention are, for example, annular components provided with a passage for the shaft and which each axially form a raceway for a rolling element on at least one side. However, they could theoretically also take on a different shape or be formed as part of another component.

[0009] A second limiting element transmits the angle of rotation to an unspecified vehicle-mounted environment. This environment could be, for example, the steering unit or a handwheel actuator. Generally, this environment is considered to be fixed to the vehicle, but can also be adjustable to accommodate different driver sizes.

[0010] The rolling element is arranged between the raceways of the limiting elements. According to the invention, the rolling element is accommodated in a bearing cage, thus forming an axial bearing ring. By being guided in a cage, additional radial rolling element guidance is unnecessary, and the raceway can be designed without radial limitation. This, in turn, opens up the possibility of making the raceway flat, which simplifies manufacturing. With a disc-shaped base element for a limiting element, which is obtained, for example, by punching from sheet metal, mechanical machining of the running surface could be omitted. The bearing cage can be made of various materials. These can be metallic materials, which are primarily processed into a bearing cage by forming, or plastics, which enable cost savings and also reduce the weight of the overall unit.

[0011] In order to achieve the function of limiting the angle of rotation, stops for the rolling element are provided in the raceways, meaning the rolling element cannot rotate completely. In its respective end position, the rolling element takes up a position between a first stop on the first limiting element and a second stop on the second limiting element, thus limiting the rotational movement of the limiting elements relative to one another. The invention is based on the finding that the side of the limiting elements facing away from the raceway has no shape requirements arising from the basic function, and that it is therefore permissible for there to be depressions in the side facing away from the raceway. This opens up the possibility of shaping the axial projections through a forming process, instead of mechanically machining the raceway into the component from an original surface, for example.Such a forming process can, for example, be an extrusion process, in which material is pressed by a punch acting on the side facing away from the raceway into a negative mold of the axial projection formed on the raceway side in the tool or die. Furthermore, a deep-drawing process is also conceivable, or a hybrid of deep-drawing and extrusion, which can be carried out in one or more stages. In summary, a characteristic of an axial projection produced by a forming process within the meaning of the invention is that the side facing away from the direction of formation in the axial direction has a recess caused by the forming process.

[0012] A shaft in the sense of the invention is to be understood in particular as a steering shaft of a handwheel actuator for a steer-by-wire steering arrangement, which provides the steering wheel or other steering device for interaction with a driver at one end and which is connected to the vehicle-fixed environment already described via a bearing.

[0013] In an advantageous embodiment of the invention, the rolling element is designed as a cylindrical roller. Rollers within the meaning of the invention can be needles or cylindrical rollers, which essentially only differ in a different length to diameter ratio. The advantage of rollers over balls is that they make line contact with their raceway and, in the case of a rotation angle limiting unit, with their stops, which means that the transmittable forces and torques are significantly higher. In a particularly advantageous embodiment of the invention, two rolling elements are used, which the person skilled in the art will arrange 180° apart to achieve a maximum rotation angle range. In order to limit a rotation angle range in terms of a configuration, a different arrangement could also be chosen. An arrangement offset by 180° is advantageous, but also in terms of a symmetrical and evenly distributed force and torque introduction.In addition, with symmetrical force introduction, the support forces on the limiting elements are equalized and these only need to be supported in a torque-transmitting manner relative to the shaft or the environment.

[0014] Due to the single-stage design, the maximum achievable angle of rotation between the stops is limited by its design. Depending on the extent of the axial projections in the circumferential direction, a maximum of one full rotation can be achieved in each direction from a central position of the limiting elements, which corresponds to the straight-ahead driving position of the vehicle, minus the space required by the design of the axial projections and the rolling element. The advantage is that the rotary motion is transmitted via a rolling element with a 2:1 ratio, since the cage with the rolling element only executes half the angle of rotation compared to the shaft.

[0015] As the number of rolling elements increases, this angular range decreases significantly. An advantageous embodiment of the invention addresses this problem by inserting additional rotation angle limiting stages between the first and second limiting elements. One rotation angle limiting stage, as defined by the invention, results for each axial bearing ring inserted between the limiting elements. Since axial bearing rings cannot rotate against each other, an intermediate ring with axial projections protruding from both sides is provided for each additional axial bearing ring.

[0016] An intermediate ring disk, in the sense of this invention, is a disk that is arranged between two axial bearing races to limit the angle of rotation. Furthermore, an intermediate ring disk is not connected to the shaft or the environment in a torque-resistant manner. An intermediate ring disk is distinguished from the first and second limiting element in that it has raceways on both sides for contact with the rolling elements of the axial bearing races and therefore also has axial projections on both sides. These axial projections are expediently arranged in such a way that a symmetrical force distribution results. With one axial projection per side, they would be 180° opposite each other; with two axial projections per side, which in turn are 180° opposite each other, the opposite side would be offset by 90°, etc. This also means, however, that the raceway area of ​​each rolling element has a recess between the two stops that limit it.If this recess is wider than the roller rolling over it, or if one end of the roller protrudes freely into the recess, the roller could enter the recess and cause jamming, for example. While the bearing cage could also prevent the roller from entering the recess, this would not be reliable for all operating conditions.

[0017] Therefore, an advantageous development of the invention is to design the rollers longer than the radial extent of the recesses. The resulting local reduction in the contact width when rolling over a recess, especially since all rollers of the rotation angle limiting unit would be affected at the same time, would normally be avoided by a person skilled in the art, as it would result in a reduced load capacity of the bearing arrangement. However, in the case of a rotation angle limiting unit, there are no or only very slight axial forces in the intermediate position between the stops, so this approach can be taken.

[0018] A particularly advantageous embodiment of the invention results if a further raceway is arranged on the first limiting element, which is connected to the shaft in a torque-resistant manner, on the side facing away from the first raceway with axial projections. This arrangement is possible due to the previously made finding that rollers which are wider than recesses can run smoothly on such a raceway as long as the load is not too great. A further axial bearing can thus be arranged on this raceway, but this axial bearing is not limited in its angle of rotation by stops in its raceway. Furthermore, this advantageous embodiment has an axial bearing disk which engages with the axial bearing which does not have a limited angle of rotation and which contacts an axially acting clamping device on the side facing away from the axial bearing.The clamping device, in turn, rests on an inner lateral stop surface of a housing, which encloses the entire angle of rotation limitation unit to form a ready-to-assemble assembly. The second limiting element rests on the opposite, second lateral stop surface of the housing. This creates a structural unit that does not introduce any axial force into the torque-tight components, i.e., the shaft and the surrounding area, either in the central position between the angle of rotation limitations or when actuated against the angle-side end stops. Furthermore, this structural unit can be easily positioned and installed by the manufacturer of the handwheel actuator. Its placement along the steering shaft is flexible, as no axial support forces need to be absorbed by the shaft, its bearings, or the surrounding area. Therefore, the shaft bearings can also be dimensioned independently, which reduces the installation space required at this point.

[0019] The housing can, for example, be manufactured as a sleeve in a deep-drawing process.

[0020] A clamping device within the scope of the invention is an elastic component within the rotation angle limiting unit, which has the task of clamping the components of the rotation angle limiting unit against each other in the axial direction and thus enabling backlash-free operation. Backlash-free operation is an important criterion for enabling low-noise and low-friction operation. The clamping device is preferably designed as a disc spring, which requires little axial space. However, alternative designs can also be considered, for example, wave springs, coil springs, or rubber elements. The geometry of the spring element can also vary, and multiple disc springs, layered springs, or progressive spring elements can be used for a non-linear spring effect.The spring element can perform additional functions, for example acting as a limiter for the axial stroke in the rotation angle limiting unit in order to keep the actuating forces within defined limits and thus prevent overloading of the bearing components.

[0021] To minimize the overall effort, the person skilled in the art will endeavor to use as few rollers as possible per stage in order to maximize the possible angle of rotation per stage and minimize the total number of stages. In the case of two rollers per stage, such an arrangement makes it possible for the bearing cage enclosing the rollers to tilt about the longitudinal axis of the rollers. Therefore, an advantageous embodiment of the invention provides for axial support elements to be provided on the bearing cages and / or on the intermediate ring disks and / or on the first and second limiting elements, which prevent or at least reduce this tilting. In addition, these support elements have the function of absorbing axial operating forces that arise from rotation in the stops. These forces are generated because the stops must be less than half the height of half the diameter of the rolling elements in order to be able to move freely against each other when rotated.Therefore, if the torque is sufficiently high, the rolling element would rise in the axial direction at the stop. If this axial movement were not impeded, the rolling element would jump over the stop, and the rotation angle limiting function of the rotation angle limiting unit would no longer be effective. This could be counteracted by geometrically designing the maximum permissible travel provided on the clamping element relative to the housing in such a way that jumping over is not possible. However, despite such a design, jumping over is still possible if the axial force deforms the components, particularly the spacer washers, to such an extent that jumping over is possible.The intermediate ring washers are particularly vulnerable in this regard, as in the design with two rolling elements per stage, i.e., two rolling elements per side, positioned 180° opposite each other, they are supported by two rolling elements on the other side, rotated 90° and also positioned 180° opposite each other, which can lead to distortion of the intermediate ring washers. The washer could be made thicker, but this would be counteracted by increased costs, additional weight, limited installation space, and the suitability of the production for formed axial projections. The axial support elements contribute to this, supporting the intermediate ring washers against the housing via the axial bearing rings and the limiting elements.

[0022] The design allows for no relative movement between the second limiting element, which is torque-tightly connected to the environment, and the housing. Since the designer is always interested in reducing the number of components, it can be advantageous to form the second limiting element as part of the housing, which represents a further advantageous embodiment.

[0023] In a further advantageous embodiment, the axial projections are designed with a ramp shape in the running direction of the rolling elements. A ramp-shaped design generates an axial movement of the rolling element, which must primarily be absorbed by the clamping device. For the driver, who turns the steering wheel to the stop, this behavior manifests itself as a gentle or dampened rotation angle end stop. In this case, it is up to the expert to decide, within the scope of the design, how many of the end stops present in the system are to be designed in this way in order to achieve the desired behavior in the rotation angle end stop. For example, the stops of the first limiting element or the second limiting element or the intermediate ring disks, or a combination thereof, could be designed with a ramp shape.

[0024] An advantageous embodiment provides for the first limiting element to be connected in a torque-resistant manner by means of a positive connection at its inner diameter, which is in contact with the shaft. In particular, a toothed arrangement is an advantageous embodiment, since toothing on the shaft and limiting element is easy to manufacture and can transmit the required torques reliably and with minimal backlash.

[0025] A further advantageous embodiment provides that the housing has a flanged collar, via which the assembly is connected to one another via a flanging process. Since the second limiting element must be connected directly or indirectly to the cylinder head in a torque-resistant manner, the flanged collar is interrupted by a recess through which a radial extension of the second limiting element extends and is supported against the surrounding area in a torque-resistant manner. It is also conceivable for the second limiting element to be supported against the housing in a torque-resistant manner, and for the housing, in turn, to be supported against the surrounding area in a torque-resistant manner. This embodiment will not be discussed further here.

[0026] In the following, a preferred embodiment is explained in more detail with reference to figures.

[0027] It shows

[0028] Fig. 1 shows a first embodiment of the rotation angle limiting unit in an exploded view,

[0029] Fig. 2 shows a first limiting element of the rotation angle limiting unit according to Fig. 1 in a plan view and a side view,

[0030] Fig. 3 shows an intermediate ring disc of the rotation angle limiting unit according to Fig. 1 in a plan view and a side view,

[0031] Fig. 4 shows a first bearing cage of the rotation angle limiting unit according to Fig. 1 in a plan view and a side view,

[0032] Fig. 5 shows a second limiting element of the rotation angle limiting unit according to Fig. 1 in a plan view and a side view,

[0033] Fig. 6 shows a housing of the rotation angle limiting unit according to Fig. 1 in a perspective view,

[0034] Fig. 7 shows a second axial bearing ring of the rotation angle limiting unit according to Fig. 1 in a plan view and a side view, Fig. 8 shows a second embodiment of a rotation angle limiting unit in an axial sectional view,

[0035] Fig. 9 shows an intermediate ring disc of the second embodiment of the rotation angle limiting unit according to Fig. 8 in a side sectional view and a perspective view,

[0036] Fig. 10 shows a third embodiment of a rotation angle limiting unit in an axial sectional view,

[0037] Fig. 11 is a front view of a rotation angle limiting unit installed in an environment, and

[0038] Fig. 12 is a schematic representation of a motor vehicle with a steer-by-wire steering system in plan view.

[0039] Figure 1 shows a first embodiment of the rotation angle limiting unit 4, which is designed to accommodate a shaft 3 rotatably mounted about the rotation axis 35 and to limit the rotation angle of this shaft. The shaft 3 is not visible in Fig. 1, but is only shown in Fig. 12. Via the first limiting element 8, the rotation angle limiting unit 4 can be connected to the shaft 3 in a torque-transmitting manner by means of a toothing 37. The first limiting element 8 has a first raceway 9 for two first rolling elements 7 designed as rollers 17. The raceway 9 is limited in the circumferential direction by two opposing first stops 10 designed as axial projections 14, which are offset from one another by 180°.

[0040] The two rollers 17, together with a first bearing cage 6, form a first axial bearing ring 5. The rollers 17 of the first axial bearing ring 5, arranged after the first limiting element 8, thus run, on the one hand, on the raceway 9 of the first limiting element 8. On the other hand, the rollers 17 are in contact with one of the raceways 20 of an intermediate ring disk 19, present on both sides. The intermediate ring disk 19 is designed on each side with two stops 21, each designed as axial projections 14. The axial projections 14 are formed from the intermediate ring disk 19 by means of a forming process. As a result, the intermediate ring disk 19 has recesses 16 on the surface 23 facing away from the axial projections 14, axially adjacent to the axial projections 14. Thus, the intermediate ring disk 19 is fundamentally designed such that it has no preferred installation direction. The same applies to the first axial bearing ring 5.The recesses 16 of the intermediate ring disc 19 are overrun on both sides by the rollers 17 rolling on the raceways 20, which is why the rollers 17 are designed to be longer than the width of the recesses 16. This allows the rollers 17 to roll over the recesses 16 without interference.

[0041] In the axial direction, the above-described first intermediate ring disk 19 is followed by a further first axial bearing ring 5, followed by a second intermediate ring disk 19, in turn followed by a third first axial bearing ring 5.

[0042] In the axial direction, the angle of rotation limiting unit 4 is closed off by a second limiting element 11. This second limiting element 11 has a second raceway 12, which is limited by two second stops 13. These second stops 13 are also formed as axial projections 14. On the side 15 facing away from the second raceway 12, the second limiting element 11 has recesses 16. In addition, two form-locking elements 34 are formed on the second limiting element 11. These form-locking elements 34 can be supported outwardly in a form-fitting manner against a geometry of the environment 2 shown in Fig. 11 and thus support the torques introduced into the shaft 3 at the angle of rotation end stop.

[0043] Configured in this way, the rotation angle limiting unit 4 shown in Figure 1 has three rotation angle limiting stages, each represented by a first axial bearing ring 5. This arrangement allows the rotation angle limiting range of the device to be adapted to the respective requirements. If a higher required rotation angle limiting range is required, further stages are added so that the rotation angle limiting unit can be easily adapted to the requirements of the application. Conversely, if the required rotation angle limiting range is smaller, stages are removed. Since this type of generation of a specific total rotation angle limiting range is quantized by a multiple of the rotation angle limiting range of the individual stage, the person skilled in the art will set a specifically required total rotation angle limiting range by modifying the rotation angle limiting range of the individual stages.This is achieved by appropriately designing the width of the axial projections 14 in the circumferential direction.

[0044] In summary, Figure 1 shows the function of the rotation angle limiter as follows: From an imaginary center position, which corresponds to the steering wheel position for straight-ahead travel, the shaft 3 and thus the first limiting element 8 are rotated in one direction. The rollers 17 transmit this rotational movement to the first intermediate ring disk 19 until they encounter the first stops 10 of the first limiting element and the stops 21 of the intermediate ring disk 19. As soon as this occurs, the intermediate ring disk 19 is carried along by the rollers 17 and thus transmits the rotational movement of the shaft 3 to the rollers 17 of the next first axial bearing ring 5.As soon as its rollers 17 hit the stops 21, in this case the two intermediate ring disks 19, the second intermediate ring disk 19 is also driven and transfers the rotational movement of the shaft 3 to the rollers 17 of the third first axial bearing ring 5 until these rollers 17 hit the second stops 13 of the second limiting element 11. Since the second limiting element 11 is torque-tightly connected to the environment 2, the rotational movement comes to a halt at this point, and the shaft 3 can no longer be rotated against the environment 2. The rotation angle limiting function is thus realized.

[0045] In this embodiment, the first limiting element 8 has, on the side 15 facing away from the first raceway 9, a further raceway 22 on which a second axial bearing ring 25 is arranged, consisting of an axial bearing cage 40 and second rollers 39. The second rollers 39 correspond dimensionally to the rollers 17 in the sense of using the same parts. Since the further raceway 22 is also interrupted by recesses 16, the second rollers 39 of the second axial bearing ring 25 are also longer than the width of the recesses 16. However, no axial projections are arranged on the further raceway 22, whereby the second axial bearing ring 25 is not limited in its angle of rotation. It is also in contact with an axial bearing disk 26, which in turn is preloaded by a clamping device 27, here designed as a disc spring. The second axial bearing ring 25 and the axial bearing disk 26 together form the axial bearing 24.The clamping device 27, in turn, rests against a stop surface 38 of a housing 28, which axially encompasses the entire torque limiting unit 4 from the clamping device 27 to the second limiting element 11. For axial closure of the torque limiting unit 4, the housing 28, which is manufactured by deep drawing without machining, is provided with a flanged collar 32, which is folded over after assembly of the individual parts. The clamping device 27 thus creates a rotation angle limiting unit 4 free of axial play, which absorbs all axial forces generated by the internal stops 10, 13, 21 and the clamping device 27 and does not transfer any axial forces to the environment.

[0046] Furthermore, recesses 33 are provided in the housing 28, which penetrate the flanged collar 32 and through which the form-locking elements 34 of the second limiting element 11 extend. Thus, the housing 28 can also be connected to the environment 2 in a torque-resistant manner indirectly via the second limiting element 11.

[0047] Furthermore, in Figure 1, four axial support elements 30 in the form of hemispherical elevations are attached to the end faces 29 of the first bearing cages 6 on each side. Since the first axial bearing rings 5 ​​only have two diagonally opposite rollers 17 each, it is possible for the first bearing cages 6 to tilt about the axes 31 of the rollers 17. This tilting is reduced or completely prevented by the axial support elements 30. Since the first bearing cages 6 are made of plastic, the axial support elements 30 can be easily produced using the injection molding process. Furthermore, the axial support elements 30 serve to absorb deformation effects in the arrangement. As soon as the rollers 17 run up against the stops 21 of the intermediate ring discs, they want to rise out of the respective raceway at the stops 21 in the axial direction, since the stops 21 must always be lower than half the roller diameter minus the space for the first bearing cages 6.This axial force is supported by the limiting elements 8, 11 and the intermediate ring discs 19. The axial support elements 30 can reduce any resulting deformation of the components.

[0048] To prevent an overly harsh stop at the end of the rotary movement, stops 10, 13, and 21 are designed with a ramp. This ensures that both the above-described entrainment of the intermediate ring discs 19 and the end stop at the end of the movement, due to a gradual increase in force, do not occur harshly and suddenly for the driver, but are gently cushioned. The ramp-shaped stops 10, 13, and 21 generate an axial movement that is absorbed by the clamping device 27. The design of the spring constant results in the desired spring effect, which manifests itself for the driver in a gentle stop sensation.

[0049] The reference numerals on the repeating elements intermediate ring disk 19 (two pieces) and first axial bearing ring 5 (three pieces) are representative of all the same elements for reasons of clarity in Figure 1 and are given only on one element.

[0050] In Figures 2-7, various individual parts of Figure 1 are shown in more detail and described in more detail below.

[0051] Figure 2 shows the first limiting element 8. This is designed as an annular, flat disk as a formed sheet metal part. A toothing 37 is attached to the inner diameter, with which the first limiting element 8 can be connected to the shaft 3 in a torque-resistant manner. The first stops 10 are formed as axial projections 14 protruding from the disk by means of a forming process. This creates recesses 16 on the opposite side 15. The axial projections 14 are ramp-shaped so that the rollers 17 contacting them do not suddenly strike the stop 10, but are first deflected slightly out of the raceway plane in the axial direction. The side 15 facing away from the axial projections 14 is designed as a further raceway 22.

[0052] Figure 3 shows a limiting element 18 designed as an intermediate ring disk 19, which is configured as a formed sheet metal part. As an intermediate ring disk 19, this limiting element 18 has raceways 20 on both sides and two stops 21, also designed as axial projections 14. These are formed so that they protrude from the intermediate ring disk 19, which is why a recess 16 is present axially adjacent to the surface 23 facing away from the respective axial projection 14. The stops 20 on one side are offset from one another by 180° in the circumferential direction. The stops 20 on the two sides are offset from one another by 90° in the circumferential direction. Furthermore, the stops 20 are ramp-shaped. Reference is made to the further description of the ramp-shaped design in Figure 2.

[0053] Figure 4 shows the first axial bearing ring 5, which consists of a first bearing cage 6 and two first rolling elements 7, which are designed as rollers 17. The rollers 17 are arranged offset from one another by 180° in the circumferential direction and form the common axis 31 from their axes of rotation. On the bearing cage 6, which is manufactured using a plastic injection molding process, support elements 30 are formed on both sides of the end faces 29 as hemispherical axial projections. For their function, reference is made to the description of Figure 1.

[0054] Figure 5 shows the second limiting element 11, which is designed as a formed sheet metal part and is also constructed as a flat disk. It forms the second raceway 12 and two second stops 13 protruding therefrom, which are designed as axial projections 14 by forming technology and therefore have recesses 16 on the side 15 facing away from the raceway. The second stops 13 are offset from one another by 180° in the circumferential direction. In addition, two form-locking elements 34 for torque support are formed on the outer diameter. On the one hand, the housing 28 is supported in a torque-resistant manner on these form-locking elements 34, and in addition, the rotation angle limiting unit 4 is supported as a whole in the environment 2 via the form-locking elements 34, which have axially extending legs bent by 90°. The form-locking elements 34 are arranged offset from one another by 180° in the circumferential direction.

[0055] Figure 6 shows the housing 28, which is manufactured using a deep-drawing process without cutting. The housing 28 has an inner stop surface 38 at one end, against which the clamping device 27 is supported. A flanged collar 32 is provided at the other axial end of the housing 28. The flanged collar 32 is interrupted by two recesses 33, which are offset from one another by 180° in the circumferential direction. The form-locking elements 34 of the second limiting element 11 engage through the recesses 33 in the rotation angle limiting unit 4, whereby the housing 28 is connected to the second limiting element 11 in a torque-resistant manner. After all individual parts of the rotation angle limiting unit 4 have been assembled, the flanged collar 32 is folded over and thus axially encloses the rotation angle limiting unit 4.

[0056] Figure 7 shows the second axial bearing ring 25, which in turn consists of a plurality of second rollers 39 distributed equidistantly around the circumference and an axial bearing cage 40. The axial bearing cage 40 is made of sheet metal.

[0057] Figure 8 shows a second embodiment of a rotation angle limiting unit 4. The arrangement of the components as well as the basic functioning of the rotation angle limiter is analogous to Figure 1, so that reference is made to the identical explanations for Figure 1. Differences arise in the design of the support elements 30. In Figure 8, these are not formed from the first bearing cages 6, but in the form of axially extending collars on the intermediate ring disks 19 and on the first and second limiting elements 8, 11. The axial projections 14 produced by forming with the axially adjacent recesses 16 in the first 8 and second limiting elements 11 are also clearly visible. Figure 9 shows an intermediate ring disk 19 from the design of the rotation angle limiting unit 4 as shown in Figure 8.Like the intermediate ring disk 19 shown in Figure 3, this intermediate ring disk 19 also has its defining elements, such as two raceways 20, two axial projections 14 on each side, and the corresponding recesses 16 on the respective opposite surface 23, due to the non-cutting manufacturing process. In addition, support elements 30 in the form of circumferential collars extending axially from the end faces 29 are formed on the inner diameter and outer diameter. This creates a Z-shape in the cross-section of the ring disk. The first bearing cages 6 of the first axial bearing rings 5, which are arranged on both sides of the intermediate ring disk 19, can be supported on these collars and thus reduce or prevent tilting about the axis of the rollers 17.

[0058] Figure 10 shows a third embodiment of the rotation angle limiting unit 4. The difference from Figures 1 and 8 again concerns the axial support elements 30, while the other basic function remains the same. In Figure 10, the axial support elements are attached to all parts involved in the torque limiting function, i.e., to the first limiting element 8, to the first axial bearing rings 5, to the intermediate ring disks 19, and to the second limiting element 11. The first limiting element 8, the first axial bearing rings 5, and the intermediate ring disks 19 have a collar on their respective outer diameters that extends axially in the direction of the next element. The second limiting element 11, the first axial bearing rings 5, and the intermediate ring disks 19 have a collar on their respective inner diameters that extends axially in the direction of the previous element.This results in a Z-shaped cross-section at the first axial bearing rings 5 ​​and the intermediate ring disks 19, while the first and second limiting elements 8, 11 have an L-shaped cross-section. Consequently, all of the described elements are supported on the adjacent elements via support elements 30 on both the inner and outer diameters, which leads to significantly increased overall rigidity when the rotation angle limiting unit 4 is rotated against the rotation angle end stop. The alternative arrangement of the support elements 30 shown in Figures 8 and 10 clearly shows that there are many possible combinations for implementing support elements 30 on the components.

[0059] Figure 11 shows the rotation angle limiting unit 4 from Figure 1 installed in an environment 2. The environment 2 can, for example, be part of a steering housing. The form-locking elements 34 are positively coupled to the environment 2 in a torque-transmitting manner. The two form-locking elements 34 are formed from the second limiting element 11 and are arranged circumferentially offset from one another by 180°. The form-locking elements 34 pass through the housing 28 at the recesses 33 and thus serve to secure the housing 28 against rotation relative to the second limiting element 11 and thus indirectly the housing 28 relative to the environment 2. Furthermore, the toothing 37 can be seen, with which the first limiting element 8 can be connected to a shaft 3 in a torque-resistant manner. The second limiting element 8 further has the recesses 16, which are located on the side facing away from a second raceway 12.The anti-rotation device in Figure 11 is supported in a similar manner by a form-fitting manner on the inner contour of the hexagonal surrounding geometry. It would also be conceivable for the form-fitting elements 34 to engage in corresponding recesses in the surrounding area.

[0060] Figure 12 shows a possible use of the angle limiting unit 4 in a steering system 1 of a vehicle 36, which, as indicated in Figure 12, has a steer-by-wire steering system. The angle limiting unit 4 is housed in a handwheel actuator, which converts the driver's steering commands into electrical signals via the angle position of shaft 3—here a steering shaft mounted for rotation about axis 35. These signals are then sent to a roadwheel actuator, which in turn mechanically converts the steering commands into a steering angle of the wheels. In principle, however, it would also be possible to use the angle limiting unit 4 for a conventional steering arrangement in which the vehicle wheels are mechanically coupled to the shaft via a steering rod.

[0061] 1 steering

[0062] 2 Surroundings

[0063] 3 Wave

[0064] 4 Angle of rotation limiting unit

[0065] 5 first axial bearing ring

[0066] 6 first bearing cage

[0067] 7 first rolling element

[0068] 8 first boundary element

[0069] 9 first career

[0070] 10 first attack

[0071] 11 second boundary element

[0072] 12 second career

[0073] 13 second attack

[0074] 14 Axial projection

[0075] 15 opposite side

[0076] 16 Return

[0077] 17 rolls

[0078] 18 Boundary element

[0079] 19 spacer discs

[0080] 20 Career

[0081] 21 stop

[0082] 22 further careers

[0083] 23 facing away surface

[0084] 24 thrust bearings

[0085] 25 second axial bearing ring

[0086] 26 Axial bearing disc

[0087] 27 clamping devices

[0088] 28 housings

[0089] 29 Frontal surface

[0090] 30 support element

[0091] 31 Axis

[0092] 32 flanged collar 33 recess

[0093] 34 Form-locking element

[0094] 35 Shaft axis

[0095] 36 Vehicle 37 Gearing

[0096] 38 Stop surface

[0097] 39 second role

[0098] 40 axial bearing cage

Claims

Claims 1 . Rotation angle limiting unit (4) for a shaft (3) of a steering system (1) of a vehicle, comprising: • a first axial bearing ring (5) comprising a first bearing cage (6) and a first rolling element (7) guided in the first bearing cage (6), • a first limiting element (8) which can be coupled to the shaft (3) in a torque-transmitting manner and which surrounds the shaft (3), which forms a first raceway (9) for the first rolling element (7) and a first stop (10) for the first rolling element (7), and • a second limiting element (11) which is connected to an environment (2) in a torque-transmitting manner and which forms a second raceway (12) and a second stop (13) for the first rolling element (7), characterized in that • at least one of the stops (10, 13) protrudes from the raceway (9, 12) as an axial projection (14) and the corresponding limiting element(s) have a recess (16) on a side (15) facing away from the raceway (9, 12) axially adjacent to the axial projection.

2. Rotation angle limiting unit (4) according to claim 1, characterized in that at least one of the axial projections (14) is formed by a forming process from the first (8) or second limiting element (11).

3. Rotation angle limiting unit (4) according to one of the preceding claims, characterized in that the first rolling body (7) is designed as a cylindrical roller (17).

4. Rotation angle limiting unit (4) according to one of the preceding claims, characterized in that the first axial bearing ring (5) has two first rolling elements (7) and the first (8) and the second limiting element (11) each have two axial projections (14).

5. Rotation angle limiting unit (4) according to one of the preceding claims, characterized in that the rotation angle limiting unit (4) has two first axial bearing rings (5) with a common limiting element (18) designed as an intermediate ring disk (19), wherein the intermediate ring disk (19) forms raceways (20) for the first rolling elements (7) on both sides, from which axial projections (14) protrude, which form stops (21) for the first rolling elements (7) and have recesses (16) on a surface (23) facing away from the raceway (20) axially adjacent to the axial projections (14).

6. Rotation angle limiting unit (4) according to claim 4 and 5, characterized in that the rollers (17) of the first axial bearing rings (5) are longer than the width of the recesses (16) of the intermediate ring discs (19) in the radial direction.

7. Rotation angle limiting unit (4) according to one of the preceding claims, characterized in that • the first limiting element (8) forms a further raceway (22) on a surface (15) facing away from the first raceway (9), on which a non-rotation angle-limited axial bearing (24) runs, comprising • a second axial bearing ring (25) and • an axial bearing disc (26), on which in turn • an axially acting clamping device (27) to • a housing (28) which axially encloses the rotation angle limiting unit (4) and absorbs axial forces generated by the clamping means (27) and / or axially acting operating forces.

8. Rotation angle limiting unit (4) according to one of the preceding claims, characterized in that the first bearing cages (6) have end faces (29), wherein one and / or both end faces (29) have axial support elements (30) for reducing or preventing tilting of the first bearing cages (6) about an axis (31) of the rollers (17) and for transmitting operating forces and / or the intermediate ring discs (19) have end faces (29), wherein one or both end faces (29) have axial support elements (30) for reducing or preventing axial tilting of the intermediate ring discs (19) and for transmitting operating forces.

9. Rotation angle limiting unit (4) according to claim 7 or 8, characterized in that the second limiting element (11) is formed as part of the housing (28).

10. Rotation angle limiting unit (4) according to one of the preceding claims, characterized in that the axial projections (14) of the first limiting element (8) and / or the axial projections (14) of the second limiting element (11) and / or the axial projections (14) of the intermediate ring discs (19) are ramp-shaped in the running direction of the rolling elements (7).

11. Rotation angle limiting unit (4) according to claim 7, characterized in that the housing (28) has a flanged collar (32), wherein the flanged collar (32) has at least one recess (33) in the circumferential direction, which is supported on a form-fitting element (34) of the second limiting element (11).

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