Push rod system with torque support device, and motor vehicle

Abstract

The present invention relates to a push rod system (1) for a steering system (2) for a motor vehicle (3), having a push rod (4) with a threaded region (5) and a form-fitting region (6), wherein the form-fitting region (6) has a form-fitting outer contour (7), wherein a ball nut for forming a ball screw drive is arranged on the threaded region (5), wherein a torque support device (8) is arranged on the form-fitting region (6), wherein the torque support device (8) is designed to form-fittingly limit a rotation of the push rod (4) relative to a steering housing (9) of the steering system (2). The torque support device (8) has a guide sleeve (10) with a sleeve outer side (12), which can be arranged in a receptacle (11) of the steering housing (9), and a sleeve inner contour (13), and a sliding bush (14), which is arranged within the guide sleeve (10) and has a bush outer contour (15) and a bush inner contour (16), wherein the sleeve inner contour (13) engages into the form-fitting outer contour (7). The invention further relates to a motor vehicle (3), having a steering system (2).

Description

[0001] Description

[0002] Push rod system with moment support device and motor vehicle

[0003] The present invention relates to a push rod system for a steering system for a motor vehicle. Furthermore, the invention relates to a motor vehicle with a steering system having a generic push rod system.

[0004] In today's conventional electromechanical steering systems with parallel-axis drive for motor vehicles, a steering movement is transmitted to a rack section of a push rod via a steering pinion, which is mechanically coupled to a steering wheel. For additional servo assistance, a motor, such as an electric motor, is mounted parallel to the push rod and is mechanically coupled to a ball screw drive, for example, via a belt as a reduction gear. The steering assistance force applied by the motor is transmitted to the push rod via the ball screw drive.

[0005] In steer-by-wire steering systems, there is typically no longer a direct mechanical connection between the steering wheel and the push rod, thus eliminating the need for a steering pinion. Steering movement of the steering wheel is detected by a sensor and transmitted to a control device that controls the electric motor. By eliminating the steering pinion, actuation of the ball screw by the electric motor can cause the push rod to rotate. Such steer-by-wire steering systems are known, for example, from documents EP 3 819 190 A1, US 2018 / 0 093 699 A1, and US 2022 / 0 048 561 A1.

[0006] Document US 2008 / 0 088 104 A1 shows a steering system in which the ball screw drive is replaced by a rack and pinion drive. With such a rack and pinion drive, no torsional moments occur, thus preventing twisting of the push rod.

[0007] A push rod guide assembly for guiding a push rod is known from document US 2021 / 0 171 096 A1. The push rod guide assembly comprises a housing with a receiving portion in which a one-piece sliding bushing is received. The sliding bushing is arranged on a push rod in a rotationally secure manner via a form-fitting portion. On one end face, the sliding bushing has a structure that interacts with a counterstructure on an inner surface of the housing and thus prevents rotation of the sliding bushing relative to the housing.

[0008] Document US 2022 / 0 001 918 A1 relates to a steer-by-wire steering system in which a plain bearing is provided, which prevents relative rotation of a push rod via a plain bearing to a steering gear housing by means of a positive fit. The plain bearing has several segments distributed around the circumference. At least one segment is designed for radial support, at least one segment is designed to prevent rotation in one direction of rotation, and at least one segment is designed to prevent rotation in the opposite direction of rotation.

[0009] A steering system in which a rotation of a push rod can be limited by an additional rotation limiting device is known from the document

[0010] WO 2020 241 091 A1. A sliding bushing is also provided to support the push rod against a bearing housing.

[0011] Conventional steering systems have the disadvantage that it is not always possible to reliably prevent the push rod from twisting during operation of the ball screw. Furthermore, the individual components can sometimes be very complex, making the steering system very complex and expensive to manufacture. Furthermore, anti-twist devices provided by plain bearings often exhibit increased friction with the push rod, so moving the push rod requires a more powerful electric motor, resulting in higher energy consumption in addition to the increased manufacturing costs.

[0012] It is therefore an object of the present invention to eliminate, or at least partially eliminate, the disadvantages described above in a steering system. In particular, it is an object of the present invention to provide a push rod system for a steering system for a motor vehicle and a steering system for a motor vehicle that prevent increased friction of the push rod and / or improve the anti-twist protection of the push rod in a simple and cost-effective manner.

[0013] The above object is achieved by the patent claims. Accordingly, the object is achieved by a push rod system for a steering system for a motor vehicle having the features of independent claim 1 and by a steering system for a motor vehicle having the features of independent claim 10. Further features and details of the invention emerge from the subclaims, the description, and the drawings. Features and details described in connection with the push rod system according to the invention naturally also apply in connection with the steering system according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0014] According to a first aspect of the invention, this object is achieved by a push rod system for a steering system for a motor vehicle. The push rod system comprises a push rod with a threaded region and a positive-locking region, wherein the positive-locking region has a positive-locking outer contour. A ball nut is arranged on the threaded region to form a ball screw drive. A torque support device is arranged on the positive-locking region, wherein the torque support device is designed to positively limit a relative rotation of the push rod to a steering housing of the steering system.According to the invention, the torque support device has a guide sleeve with a sleeve outer side that can be arranged in a receptacle of the steering housing and a sleeve inner contour and a sliding bushing arranged within the guide sleeve with a bushing outer contour and a bushing inner contour, wherein the sleeve inner contour engages in the positive-locking outer contour of the push rod.

[0015] The push rod system is particularly suitable for a steer-by-wire steering system in which there is no mechanical connection between a steering wheel and the push rod. The push rod system is therefore particularly suitable for a steer-by-wire steering system which does not have a steering pinion that engages with a rack section of the push rod. Thus, it is preferred that the push rod does not have a rack section. The push rod system is particularly designed for an axially parallel drive in which the motor for driving the ball nut of the ball screw drive is arranged next to the push rod and axially parallel to the push rod. For torque transmission from the motor to the ball nut, a belt, a gearing or the like can be provided, for example.

[0016] The push rod has several push rod sections. These include the threaded section and the positive-locking section. The threaded section forms part of the ball screw drive. The positive-locking section is designed to support the push rod and to prevent or at least limit the rotation of the push rod about its longitudinal axis. End sections of the push rod formed in the longitudinal direction are preferably designed to be coupled to a respective tie rod for steering a wheel of the motor vehicle.

[0017] The ball nut is located on the threaded portion. The ball nut is designed for mechanical coupling to a steering system drive, such as an electric motor. The ball nut, which is preferably fixedly mounted on the bearing housing, is rotatable via the electric motor. This rotation causes balls of the ball nut to roll on the threaded portion, exerting a force on the push rod, which causes a translational movement of the push rod. In this way, the steering angle of the vehicle's wheels can be specifically changed.

[0018] A positive locking region is understood to be a push rod region of the push rod that deviates from a circular cross-section formed coaxially to the longitudinal axis of the push rod. The positive locking outer contour of the positive locking region can, for example, have one or more cams that protrude radially outward. Preferably, the positive locking outer contour has two cams, which are preferably arranged offset by 180° in the circumferential direction. More preferably, the positive locking outer contour has four cams, which are preferably arranged offset by 90° in the circumferential direction. Particularly preferably, the positive locking outer contour has six cams, which are preferably arranged offset by 60° in the circumferential direction.

[0019] The cams preferably extend along the longitudinal axis of the push rod in the form-locking region. Preferably, the cross-section of the push rod in the form-locking region is symmetrical. Particularly preferably, the cross-section of the push rod in the form-locking region is symmetrical, with two axes of symmetry, preferably three axes of symmetry, and particularly preferably with four or six axes of symmetry. The form-locking region is designed in such a way that a sliding bushing can slide smoothly over the form-locking region. Accordingly, it is preferred that the form-locking region have a ground and / or polished surface. A cold-drawn or rolled surface is preferably used.

[0020] To better support the push rod and prevent rotation of the push rod about its longitudinal axis relative to the steering housing, the torque support device is arranged on the form-fitting area. The torque support device comprises the guide sleeve and the sliding bushing arranged within the guide sleeve. The guide sleeve and the sliding bushing are preferably designed as separate components that are assembled such that the guide sleeve surrounds the sliding bushing. The guide sleeve and the sliding bushing preferably extend coaxially to the longitudinal axis of the push rod.

[0021] The sliding bushing has an outer bushing contour and an inner bushing contour. The inner bushing contour engages with the positive-locking outer contour of the positive-locking area, preferably such that the inner bushing contour encompasses the positive-locking outer contour and rests against the positive-locking outer contour. It is preferred that the sliding bushing completely surrounds the push rod in the positive-locking area. The inner bushing contour preferably has a particularly low coefficient of friction to promote relative sliding of the push rod relative to the sliding bushing. The outer bushing contour faces the guide sleeve.

[0022] The guide sleeve has the outer sleeve side and the inner sleeve contour. The outer sleeve side is designed for arrangement in the receptacle of the steering housing. The receptacle preferably has a circular cross-section. Accordingly, the guide sleeve on the outer sleeve side preferably also has a circular cross-section. The outer sleeve side and the receptacle are preferably designed according to a fit, such as a clearance fit or a press fit, in order to ensure that the guide sleeve is securely held in the receptacle. Furthermore, this improves the alignment and centering of the guide sleeve with respect to the receptacle. To prevent relative movement of the guide sleeve to the steering housing along the longitudinal axis, the receptacle preferably has a stop, such as an annular stop, and an annular groove for a removable fixing ring.

[0023] The inner contour of the sleeve faces the outer contour of the bushing and engages with it. The guide sleeve and the sliding bushing are further designed such that the inner contour of the sleeve also engages with the positive-locking outer contour. This engagement can be achieved, for example, by cams and corresponding recesses. Thus, in the circumferential direction of the push rod, at least one push rod region of the push rod is arranged next to a bushing region of the sliding bushing and a sleeve region of the guide sleeve. A torsional moment introduced into the push rod via the ball screw drive can therefore be transferred to the guide sleeve along a linear force path via the positive-locking outer contour and the sliding bushing.

[0024] A push rod system according to the invention for a steering system for a motor vehicle has the advantage over conventional push rod systems that, by providing a linear force path in the circumferential direction between the push rod and the torque support device, relative twisting of the push rod to the steering housing is reliably prevented using simple means and in a cost-effective manner. Due to the multi-layer design, the torque support device, in interaction with the push rod, exhibits particularly low friction, so that particularly low forces are required for the translational relative movement of the push rod to the torque support device. A motor of the steering system can thus have lower power and therefore lower weight and smaller dimensions. Finally, the torque support device is easy to manufacture, simple to assemble, and can be disassembled without great effort.

[0025] According to a preferred further development of the invention, in a push rod system, the bushing outer contour can engage the sleeve inner contour. Thus, the moment support device has at least one first inner region, in which the sleeve inner contour of the guide sleeve engages the bushing outer contour of the sliding bush, and at least one second inner region, in which the bushing outer contour engages the sleeve inner contour. Preferably, the moment support device has a plurality of first inner regions and a plurality of second inner regions. The engagement can be realized, for example, by cams and corresponding recesses. This has the advantage that, with simple means and in a cost-effective manner, a particularly reliable anti-twist device for the push rod in both possible directions of rotation is provided with relatively low friction between the moment support device and the push rod.

[0026] It is preferred according to the invention that the sliding bushing predominantly or completely covers the inner contour of the sleeve in the radial direction relative to the push rod. Complete covering is understood in the context of the invention to mean that the push rod is completely covered by the sliding bushing in a partial area of ​​the form-fitting region in which the moment support device is arranged, in the radially outward direction. In this partial area, the sliding bushing does not allow direct contact between the push rod and the guide sleeve. Only indirect contact is provided via the sliding bushing. With predominantly covering, the sliding bushing can have clearances such as longitudinal slots, feedthroughs or the like. Direct contact between the push rod and the guide sleeve is preferably further prevented by the sliding bushing.This has the advantage that a particularly reliable anti-twist device for the push rod is provided using simple means and in a cost-effective manner with relatively low friction between the moment support device and the push rod.

[0027] More preferably, the sliding bushing has a first bushing body and a second bushing body, wherein the first bushing body is arranged in the radial direction between the push rod and the second bushing body, wherein the first bushing body has a higher rigidity than the second bushing body. In other words, a distance of the second bushing body to the longitudinal axis of the push rod is greater than a distance of the first bushing body to the longitudinal axis. The second bushing body is preferably arranged on the first bushing body or held on the first bushing body. Preferably, the second bushing body is arranged on a section of the first bushing body which has a greater distance from the longitudinal axis than an average distance of the first bushing body to the longitudinal axis.Particularly preferably, the second bushing body is arranged on a section of the first bushing body which has a maximum distance from the longitudinal axis compared to all other sections of the first region. It is preferred that the first bushing body completely or at least predominantly surrounds the push rod. Further preferably, the first bushing body is formed in one piece or monolithically. It is preferred that the second bushing body only covers part of the first bushing body. Preferably, the sliding bush has a plurality of second bushing bodies. The second bushing bodies are preferably arranged separately on the first bushing body. The second bushing bodies are preferably distributed evenly over the first bushing body in the circumferential direction. Particularly preferably, all second bushing body segments are connected to one another. The first bushing body has a higher rigidity than the second bushing body.As a result, for example, torsional moments of the push rod can be absorbed more directly, small radial relative movements, such as vibrations, can be better dampened, and dimensional and shape deviations of the positive-locking outer contour and the sleeve inner contour can be compensated. The first bushing body and the second bushing body are preferably made of different materials. The first bushing body preferably comprises a rigid thermoplastic, such as modified POM, modified PA, or the like. The second bushing body preferably comprises a flexible elastomer, such as rubber, thermoplastic elastomer, or the like. The sliding bush is preferably manufactured using a two-component injection-molding process. Alternatively, the second bushing body can also be injection-molded or vulcanized onto the first bushing body arranged in an injection mold.This has the advantage of providing a particularly reliable anti-twist mechanism for the push rod using simple and cost-effective means, with relatively low friction between the moment support device and the push rod. Furthermore, vibrations in the push rod system are better dampened.

[0028] In a particularly preferred embodiment of the invention, in a push rod system, the second bushing body can have a plurality of sliding bushing segments, wherein the sliding bushing segments each have two longitudinal webs extending in the longitudinal direction. The longitudinal webs thus have a smaller width than length. In the radially outward direction, the longitudinal webs preferably have a taper, tip, rounding or the like. Preferably, the second bushing body has two longitudinal webs which are connected to one another at one end via a transverse web. Preferably, the longitudinal webs are monolithic with the transverse web. More preferably, the longitudinal webs are arranged parallel to one another and, together with the transverse web, have a U-shaped configuration.This has the advantage of providing a particularly reliable anti-rotation lock for the push rod using simple and cost-effective means, with relatively low friction between the moment support device and the push rod, and compensating for dimensional and shape deviations of the positive-lock outer contour and the inner contour of the sleeve. Furthermore, vibrations of the push rod system are better dampened.

[0029] The sliding bushing preferably has a plurality of transverse webs between the sliding bushing segments of the second bushing body, resulting in longitudinal slots extending in the longitudinal direction. The longitudinal slots are preferably also formed in the first bushing body of the sliding bushing. More preferably, the longitudinal slots are formed in a bushing region of the sliding bushing which is at a greater distance from the longitudinal axis than other bushing regions of the sliding bushing. The longitudinal slots are greater in length than in width. The longitudinal slots allow small tolerances between the push rod and the sliding bushing to be better compensated. The longitudinal slots further reduce friction between the sliding bushing and the push rod. It is preferred that the longitudinal slots, together with the transverse slots, form an S-shape, preferably a continuous S-shape, which extends circumferentially over the bushing body.This has the advantage that a particularly reliable anti-twist device for the push rod is provided using simple means and in a cost-effective manner with relatively low friction between the moment support device and the push rod. According to a preferred embodiment of the invention, in a push rod system, the transverse webs can be arranged alternately on the first end face and the second end face. The longitudinal webs are preferably connected to one another in pairs by the transverse webs. This ensures flexibility of the sliding bush. Thus, the longitudinal slots are open in the longitudinal direction towards the first end face and closed towards an opposite second end face.This has the advantage that a particularly reliable anti-twist device for the push rod is provided using simple means and in a cost-effective manner with relatively low friction between the moment support device and the push rod.

[0030] Particularly preferably, the guide sleeve is designed as a cold-formed part. Alternatively, the guide sleeve can also be designed as a sintered part or as an additively manufactured component. A cold-formed part is particularly easy and cost-effective to manufacture and is therefore well-suited for series production. Furthermore, such a guide sleeve reliably transmits the torque of the push rod to the steering housing mount. This has the advantage of providing a particularly reliable anti-twist device for the push rod using simple means and in a cost-effective manner.

[0031] It is preferred according to the invention that the guide sleeve has knurling on the outside of the sleeve. The knurling is preferably formed over its entire circumference on the outside of the sleeve. In the longitudinal direction, preferably only a portion of the outside of the sleeve has such knurling. The knurling creates a positive connection between the guide sleeve and the steering housing mount, thus preventing relative rotation of the torque support to the mount. This has the advantage of providing a particularly reliable anti-twist device for the push rod using simple means and in a cost-effective manner.

[0032] According to a second aspect of the invention, the object is achieved by a motor vehicle. The motor vehicle has a steering system. According to the invention, the steering system has a push rod system according to the invention.

[0033] The steering system is preferably designed as a steer-by-wire steering system. There is preferably no mechanical connection between a steering wheel of the steering system and the push rod. A steering pinion is therefore preferably not present. Likewise, the push rod preferably does not have a rack section. The steering system preferably has a steering housing in which a receptacle is formed. The torque support device of the push rod system according to the invention is arranged in the receptacle, preferably with frictional engagement, in a rotationally secure manner. The receptacle preferably has a circular cross-section. The guide sleeve therefore preferably also has a flexible circular cross-section on the outer side of the sleeve. The outer side of the sleeve and the receptacle are preferably designed according to a press fit in order to ensure that the guide sleeve is securely held in the receptacle.

[0034] Preferably, a relative movement of the torque support device to the receptacle in the longitudinal direction is prevented, preferably in a form-fitting manner, for example by a shoulder on the receptacle extending radially inward and a fixing ring arranged in a circumferential groove of the steering housing on the receptacle. Preferably, the fixing ring and / or the shoulder contact the end faces of the guide sleeve of the torque support device. More preferably, the fixing ring and / or the shoulder do not contact the sliding bushing of the torque support device. Preferably, a gap is formed between the sliding bushing and the fixing ring and / or the shoulder.

[0035] To move the push rod, the steering system preferably has a motor, such as an electric motor, arranged axially parallel to the push rod in or on the steering housing. The motor is mechanically coupled to the ball nut, for example, via a belt, gearing, or the like, to set the ball nut in a rotational motion.

[0036] The motor vehicle according to the invention offers all the advantages already described for a push rod system according to the first aspect of the invention. Accordingly, the motor vehicle according to the invention has the advantage over conventional motor vehicles that, by providing the linear force path in the circumferential direction between the push rod and the torque support device of the steering system, relative twisting of the push rod to the steering housing is reliably prevented using simple means and in a cost-effective manner. Due to the multi-layer design, the torque support device, in interaction with the push rod, has particularly low friction, in addition to the ability to compensate for manufacturing tolerances, thermal expansion effects, and wear, so that particularly low forces are required for the translational relative movement of the push rod to the torque support device.The motor of the steering system can thus have a lower power output and thus a lower weight and smaller dimensions. Finally, the steering system is easy to manufacture, simple to assemble, and disassemble without great effort. A push rod system according to the invention for a steering system for a motor vehicle, as well as a motor vehicle according to the invention with a steering system having a push rod system according to the invention, are explained in more detail below with reference to the drawings.

[0037] They show schematically:

[0038] Figure 1 shows a sectional view of a section of a push rod system according to a preferred first embodiment of the invention,

[0039] Figure 2 shows a frontal plan view of the push rod system from Figure 1,

[0040] Figure 3 shows a perspective view of a section of a preferred embodiment of a push rod for a push rod system according to the invention,

[0041] Figure 4 shows a perspective view of a preferred embodiment of a guide sleeve for a push rod system according to the invention,

[0042] Figure 5 shows a perspective view of a preferred first embodiment of a sliding bush for a push rod system according to the invention,

[0043] Figure 6 shows a perspective view of a preferred second embodiment of a sliding bush for a push rod system according to the invention

[0044] Figure 7 shows a sectional view of a section of a preferred embodiment of a push rod system according to the invention, and

[0045] Figure 8 shows a side view of a preferred embodiment of a motor vehicle according to the invention.

[0046] Elements with the same function and mode of operation are provided with the same reference numerals in Figures 1 to 8.

[0047] Fig. 1 shows a section of a push rod system 1 for a steering system 2 (cf. Fig. 8) according to a preferred first embodiment of the invention, schematically in a sectional view. Fig. 2 shows the push rod system 1 from Fig. 1 schematically in a sectional view of a sectional plane S. The push rod system 1 has a push rod 4 with a threaded area 5 for receiving a ball nut (not shown) and a form-fitting area 6 with a form-fitting outer contour 7. The push rod 4 extends along a longitudinal direction L and in a radial direction R. The form-fitting outer contour 7 has six form-fitting elements which stand out outwards in the radial direction R from other areas of the form-fitting outer contour 7 and extend parallel to the longitudinal direction L.

[0048] To radially support the push rod 4 and to prevent rotation of the push rod 4, the push rod system 1 has a torque support device 8. The torque support device 8 has a guide sleeve 10 with a sleeve outer surface 12 and a sleeve inner contour 13. The guide sleeve 10 is received in a receptacle 11 of a steering housing 9 of the steering system 2 such that the sleeve outer surface 12 contacts an inner wall of the receptacle 11, preferably in a press fit. To limit a relative movement of the guide sleeve 10 to the steering housing 9 in the longitudinal direction L, the steering housing 9 has a stop 25 on one side of the guide sleeve 10 and a fixing ring 26 on another side of the guide sleeve 10.

[0049] Furthermore, the moment support device 8 has a sliding bushing 14 with a bushing outer contour 15 and a bushing inner contour 16. The sliding bushing 14 is arranged within the guide sleeve 10 such that the bushing outer contour 15 engages the sleeve inner contour 13. Preferably, the sliding bushing 14 is pressed into the guide sleeve 10. The sliding bushing 14 is also arranged on the form-fitting area 6 of the push rod 4 such that the form-fitting outer contour 7 engages the bushing inner contour 16 and the sleeve inner contour 13.

[0050] Fig. 3 shows a schematic perspective view of a preferred embodiment of a push rod 4 for a push rod system 1 according to the invention. The illustrated section shows the positive-locking region 6 of the push rod 4 with the positive-locking outer contour 7. The positive-locking outer contour 7 is cam-shaped.

[0051] Fig. 4 shows a preferred embodiment of a guide sleeve 10 for a push rod system 1 according to the invention, schematically in a perspective view. In this embodiment, a knurling 22 is arranged on the outer side 12 of the guide sleeve 10 to prevent relative rotation of the guide sleeve 10 to the steering housing 9. Remaining areas of the outer side 12 of the sleeve can, for example, be smooth.

[0052] Fig. 5 shows a schematic perspective view of a preferred first embodiment of a sliding bushing 14 for a push rod system 1 according to the invention. The sliding bushing 14 has a one-piece first bushing body 17 with six sliding bushing segments 27, which are alternately connected by means of transverse webs 28 and thus form a unit, with a first end face 21 and a second end face 24. This results in a plurality of longitudinal slots 20 in the first bushing body 17, which extend in the longitudinal direction L. The longitudinal slots 20 are thus distributed evenly over a circumference of the sliding bushing 14. The longitudinal slots 20 are each open alternately towards the first end face 21 and the second end face 24 and each end inside the first bushing body 17 at the respective transverse web 28.On a section of the first bushing body 17 that is furthest outward in the radial direction R, a plurality of second bushing bodies 18 of the sliding bushing 14 are arranged. The second bushing bodies 18 each have two longitudinal webs 19 per sliding bushing segment 27, which extend in the longitudinal direction L and form a maximum extension of the sliding bushing 14 in the radial direction R. The flexible longitudinal webs 19 are arranged such that they press the intermediate sliding bushing segment 27 of the first bushing body against the side surfaces of two adjacent cams of the positive-locking outer contour 7. This ensures a play-free transmission of torsional loads from the push rod 4 to the sliding bushing 14.The transfer of torsional load from the sliding bushing 14 to the guide sleeve 10 preferably has a narrow transition area with reduced rigidity during rotational direction changes, resulting from the combination of preload of the longitudinal webs 19, freewheeling between the longitudinal webs of the guide sleeve 10 on the inner sleeve contour 13 and the outer bushing contour 15, and the resulting deformation work to bridge the gap during rotational direction changes. A minimum gap size and overlap area of ​​the flexible components is preferably maintained to ensure backlash-free operation under all geometric, environmental, and aging influences.

[0053] Fig. 6 shows a preferred second embodiment of a sliding bushing 14 for a push rod system 1 according to the invention, schematically in a perspective view. The second embodiment differs from the first embodiment in the design of the second bushing bodies 18. The second bushing bodies 18 each have two longitudinal webs 19, which are formed monolithically with a common transverse web 23. A longitudinal slot 20 is arranged between each of the longitudinal webs 19 of a second bushing body 18. The transverse web 23 is arranged on the closed side of the longitudinal slot 20.

[0054] Fig. 7 shows a schematic sectional view of a preferred embodiment of a push rod system 1 according to the invention. This view shows that the flexible second bushing bodies 18 press against the guide sleeve 10 in the radial direction R. The stiffer first bushing body 17 rests circumferentially against the form-fitting contour 7 and the inner contour 13 of the sleeve, thus ensuring particularly reliable anti-rotation protection of the push rod 4.

[0055] Fig. 8 shows a preferred embodiment of a motor vehicle 3 according to the invention schematically in a side view. The motor vehicle 3 has a steering system 2 with a push rod system 1 according to the invention.

[0056] List of reference symbols

[0057] Push rod system Steering system Motor vehicle Push rod Threaded area Form-fit area Form-fit outer contour Torque support device Steering housing

[0058] 10 guide sleeve

[0059] 1 1 recording

[0060] 12 Sleeve outside

[0061] 13 Sleeve inner contour

[0062] 14 sliding bushing

[0063] 15 Bushing outer contour

[0064] 16 Bushing inner contour

[0065] 17 first socket body

[0066] 18 second socket body

[0067] 19 Longitudinal web

[0068] 20 longitudinal slot

[0069] 21 first front side

[0070] 22 Knurling

[0071] 23 Crossbar

[0072] 24 second front side

[0073] 25 stops

[0074] 26 Fixing ring

[0075] 27 sliding bushing segment

[0076] 28 Crossbar

[0077] L longitudinal direction

[0078] R radial direction

[0079] S cutting plane

Claims

Patent claims 1 . A push rod system (1) for a steering system (2) for a motor vehicle (3), comprising a push rod (4) with a threaded region (5) and a form-fitting region (6), wherein the form-fitting region (6) has a form-fitting outer contour (7), wherein a ball nut is arranged on the threaded region (5) to form a ball screw drive, wherein a moment support device (8) is arranged on the form-fitting region (6), wherein the moment support device (8) is designed to form-fit a relative rotation of the push rod (4) to a steering housing (9) of the steering system (2), characterized in that the moment support device (8) comprises a guide sleeve (10) with a sleeve outer side (12) that can be arranged in a receptacle (11) of the steering housing (9) and a sleeve inner contour (13), and a sliding bushing (14) arranged within the guide sleeve (10) with a bushing outer contour (15) and a bushing inner contour (16),wherein the sleeve inner contour (13) engages in the form-fitting outer contour (7)., 2. Push rod system (1) according to claim 1, characterized in that the bushing outer contour (15) engages in the sleeve inner contour (13).

3. Push rod system (1) according to claim 1 or 2, characterized in that the sliding bush (14) covers the sleeve inner contour (13) in the radial direction (R) predominantly or completely relative to the push rod (4).

4. Push rod system (1) according to one of the preceding claims, characterized in that the sliding bush (14) has a first bushing body (17) and a second bushing body (18), wherein the first bushing body (17) is arranged in the radial direction (R) between the push rod (4) and the second bushing body (18), wherein the first bushing body (17) has a higher rigidity than the second bushing body (18).

5. Push rod system (1) according to claim 4, characterized in that the second bushing body (18) has a plurality of sliding bushing segments (27), wherein the sliding bushing segments (27) have two longitudinal webs (19) extending in the longitudinal direction (L).

6. Push rod system (1) according to one of the preceding claims, characterized in that the sliding bush (14) has a plurality of transverse webs (28) between the sliding bush segments (27) of the second bush body (18), resulting in longitudinal slots (20) extending in the longitudinal direction (L).

7. Push rod system (1) according to claim 6, characterized in that the transverse webs (28) are arranged alternately on the first end face (21) and the second end face (24).

8. Push rod system (1) according to one of the preceding claims, characterized in that the guide sleeve (10) is designed as a cold-formed part.

9. Push rod system (1) according to one of the preceding claims, characterized in that the guide sleeve (10) has a knurling (22) on the outer side (12) of the sleeve.

10. Motor vehicle (3) comprising a steering system (2), characterized in that the steering system (2) comprises a push rod system (1) according to one of the preceding claims.

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