Adjustment drive for steering column of motor vehicle and steering column for motor vehicle

Abstract

The invention relates to an adjustment drive (5) for a steering column (1) of a motor vehicle, comprising a threaded spindle (52), which extends axially in the direction of a spindle axis (G) and engages with a spindle nut (51), and a drive unit (55), by means of which the threaded spindle (52) and the spindle nut (51) are driven in relative rotation; wherein the drive unit (55) has a gear mechanism comprising a worm (56) which can rotate about a worm axis (W) transverse to the spindle axis (G), and a worm thread (57) of the worm engages with a toothing (72) of a gear (7) which is coaxially connected to the threaded spindle (52) or the spindle nut (51), the threaded teeth (57) of the worm thread engage with a tooth space (74) between two adjacent teeth (73) of the toothing (72) of the gear (7), and wherein a locking device is provided, which can be placed in a locking position in order to fix the threaded spindle (52) relative to the spindle nut (51). In order to achieve a high level of safety at low cost, the invention proposes that the toothed wheel (7) and the worm (56) can be moved relative to each other in the direction of the spindle axis (G), and that the toothing (72) and the worm thread are designed to convert the relative axial displacement into a reduction in the backlash between the toothed wheel (72) and the worm (56).

Description

Existing technology

[0001] The present invention relates to an adjustment drive for a motor vehicle steering column, comprising a threaded spindle extending axially in the direction of the spindle axis and meshing with a spindle nut, and a drive unit by which the threaded spindle and the spindle nut are driven for relative rotation. The drive unit has a gear mechanism comprising a worm rotatable about a worm axis transverse to the spindle axis, the worm thread of the worm meshing with a toothed portion of a gear coaxially connected to the threaded spindle or the spindle nut, the thread teeth of the worm thread meshing with a tooth groove between two adjacent teeth of the toothed portion, and a locking device provided that can be placed in a locked position to secure the threaded spindle relative to the spindle nut. The present invention also relates to a steering column having such an adjustment drive.

[0002] The steering column comprises a carrier unit that can be mounted on the vehicle body, the carrier unit supporting an actuating unit, in which a steering spindle is mounted and rotatably mounted about its longitudinal axis extending in the longitudinal direction. To set an ergonomic operating position, the position of a steering wheel mounted on the steering spindle can be adjusted relative to the carrier unit, in particular longitudinally in the direction of the longitudinal axis and / or, as an alternative, vertically up and down perpendicular to the longitudinal axis.

[0003] For example, the motor-driven adjustment drive can include a linear actuator drive driven by an electric motor for longitudinal adjustment, which can act on the actuating unit and the housing unit, wherein the actuating unit can be adjusted telescopically in the longitudinal direction. For vertical adjustment, the adjustment drive can be arranged between the carrier unit and the actuating unit pivotally supported thereby.

[0004] Typically, the adjustment drive is designed as a spindle drive, in which the external threads of a threaded spindle, extending along its spindle axis, engage in a spindle nut. When driven to rotate by a motor drive unit, the threaded spindle and spindle nut can move relative to each other along the spindle axis. To adjust the steering column, the threaded spindle and spindle nut are connected to components within the steering column that can be adjusted relative to each other, such as the actuating unit and the carrier unit.

[0005] To ensure fast and smooth adjustment with low drive forces, the spindle drive is designed to minimize friction. Consequently, large external forces acting on the adjustment drive along the spindle axis—for example, high force peaks from a vehicle impacting the steering wheel in a crash—can cause the threaded spindle and spindle nut to rotate relative to each other, leading to slippage in the adjustment drive. This can lead to uncontrolled relative movement of the carrier unit and actuating unit, which can have adverse safety implications. For example, in the event of a crash, the effectiveness of energy absorbers, which are located between the actuating unit and the carrier unit to control the dissipation of kinetic energy, can be compromised.

[0006] To prevent the adjusting drive from slipping under high external loads, DE 10 2017 201594 B1 discloses a locking device that can be brought into a fixed position in the event of a crash to secure the adjusting drive in the set adjustment position. To this end, the threaded spindle and spindle nut are fixed relative to each other so that the spindle drive cannot yield in the adjustment direction and, even under high force peaks in a crash, does not slip, but instead forms a rigid force transmission element. This ensures that, particularly in the event of a crash, the forces introduced into the actuating unit are transmitted almost completely, as intended, to the energy absorption device disposed between the actuating unit and the support unit, thereby achieving optimal and controlled energy absorption.

[0007] However, although the known locking device is effective, it requires an additional locking element to be provided between the threaded spindle and the spindle nut, thereby increasing the design and production costs.

[0008] In view of the above problems, an object of the present invention is to achieve a higher security level at a lower cost. Summary of the Invention

[0009] The object of the invention is achieved by an adjustment drive according to claim 1 and a steering column according to claim 11. Further developments can be found in the dependent claims.

[0010] In an adjustment drive device for a steering column of a motor vehicle, it includes a threaded spindle, which extends axially in the direction of the spindle axis and engages with a spindle nut, and a drive unit, by which the threaded spindle and the spindle nut are driven to rotate relative to each other, the drive unit having a gear mechanism, the gear mechanism including a worm, which can rotate around a worm axis transverse to the spindle axis, the worm thread of the worm engaging with the tooth portion of a gear coaxially connected to the threaded spindle or the spindle nut, wherein the thread teeth of the worm thread engage with the tooth groove between two adjacent teeth of the tooth portion, and a locking device is provided, which can be placed in a locking position so as to fix the threaded spindle relative to the spindle nut. According to the present invention, the gear and the worm can move relative to each other in the direction of the spindle axis, and the tooth portion and the worm thread are designed to convert the relative axial displacement into a reduction in the tooth gap between the gear and the worm.

[0011] As known in the prior art, this drive device features a gear mechanism configured as a worm gear, located between an electric motor and a spindle drive. The motor rotates the worm about its worm axis, with its worm thread meshing with a gear configured as a worm gear. In so-called immersed spindle drives, the threaded spindle is fixed with respect to rotation, and the gear is fixedly connected to the spindle nut, allowing the spindle nut to be driven in rotation. In rotating spindle drives, the spindle nut is mounted in a rotationally fixed manner on the steering column, while the threaded spindle is connected to the gear.

[0012] According to the present invention, the locking device in the gear mechanism is implemented by the cooperation between the gear and the worm. Here, the locking device holds the worm and the gear relative to each other so that under the action of high axial forces, i.e., forces applied in the direction of the main shaft axis, the worm can be displaced in the axial direction and loaded onto the gear.

[0013] Thanks to the design according to the present invention, high external forces acting on the adjustment drive in the adjustment direction, such as the impact force generated by a person striking the steering wheel in a collision, are transmitted axially to the main shaft gear of the adjustment drive. This causes relative axial displacement of the gear and worm along the main shaft axis.

[0014] According to the present invention, the backlash is reduced due to the relative displacement, resulting in a greater friction force on the contact surface between the worm and the gear meshing with the toothed gear. Therefore, the design according to the present invention can also be defined as follows: the gear teeth and the worm are configured to convert relative axial loads into an increase in meshing friction between the gear and the worm. Due to the reduced backlash or increased gear friction under the action of external forces, the worm wheel enters a self-locking state. The resulting increased friction prevents the gear from rotating about the spindle axis. Therefore, when a high external axial force acting in the adjustment direction applies a counter-torque to the spindle nut or the threaded spindle, the gear rotates relative to the worm.

[0015] In the present invention, the spindle drive is locked and fixed in its current adjusted position simply by axially displacing the gear and worm. This ensures that the steering column will not compress uncontrollably even under extremely high external loads, such as in a crash. This ensures the perfect functioning of safety systems, such as the energy absorption system.

[0016] One advantage of the present invention is that self-locking can be activated simply by designing the gear and worm accordingly, without requiring additional locking elements or the like. This allows for an advantageously simplified design and a compact construction with low weight, while at the same time ensuring high functional reliability by eliminating additional moving parts.

[0017] In an advantageous embodiment, a triggering threshold can be formed between the gear and the worm. This can be achieved by a retaining device that, during normal operation, holds the worm and gear in a defined meshing position relative to each other. As long as the axial force acting on the adjustment drive—in particular, the adjustment force—is below a predefined limit value, the relative position of the worm and gear remains unchanged. Only when a defined limit force is exceeded, such as in the event of a high force peak in a crash, does relative axial displacement between the gear and worm occur. This has the advantage that, during normal operation and under the expected loads on the adjustment drive, the locking device according to the present invention cannot be accidentally activated, while simultaneously achieving the lowest possible gear friction. The triggering threshold can, for example, be achieved by a defined friction, wherein the force threshold is achieved through a frictional connection. Alternatively or additionally, a pre-breaking element, a deforming element, or the like can be provided that allows relative movement of the worm and gear when a predefined limit force is exceeded.

[0018] An advantageous embodiment can provide that the individual tooth gaps taper at least partially in a wedge-shaped manner in the direction of their longitudinal extension.

[0019] The tooth gaps form the groove-like depressions between two adjacent teeth. In their longitudinal extension—along the direction of the tooth, also referred to as the "tooth direction"—the tooth gaps extend between the tooth width or tooth section width, between the two axial end faces of the tooth section. The tooth section is preferably designed as helical gear teeth, with the teeth extending at an angle relative to the longitudinal axis. In this case, the tooth gaps also extend at an angle in the tooth direction, and preferably all tooth gaps taper in a wedge-shaped manner.

[0020] When the axial extension of the tooth gap is mentioned herein, this means that the tooth gap extends in the longitudinal direction of the tooth direction.

[0021] The thread teeth of the worm have a defined thread cross-section that preferably remains constant during the spiraling process and engages with a positive fit in the open cross-section of the tooth gap. A certain clearance is predefined between the tooth flanks of the thread teeth and the opposing contact surfaces of the tooth gap, which allows for low-friction torque transmission.

[0022] Under the action of an axial impact force, the worm is displaced axially relative to the gear (hereinafter referred to as the force direction or impact direction), perpendicular to its worm axis. This load causes the threaded portion of the worm, meshing with the toothed gear, to move in the longitudinal direction of the tooth gap (i.e., the tooth direction). This causes the thread teeth to become wedged between the inner surfaces of the tooth gap, which gradually converge in a wedge-shaped manner in the tooth direction. Consequently, the backlash between the contact surfaces of the thread teeth and the tooth gap is reduced to zero when meshing, generating greater friction between the worm and gear.

[0023] The advantage of the above design is that the advantages of the present invention can be achieved simply by configuring the gear teeth accordingly.

[0024] Provision can be made for the width of the tooth gap to decrease at least partially in the tooth direction. A tooth gap extends in the tooth direction between two teeth. Its width, measured circumferentially at a specific diameter (e.g., the reference diameter of the gear), is also referred to as the slot width. The slot width therefore represents the distance between two inner surfaces of the tooth gap, measured circumferentially, which face each other and are referred to as slot flanks. Unlike the prior art, where the slot width remains constant along the tooth width in the tooth direction, the present invention allows the slot width to taper in a wedge-shaped manner. One advantage of this is that, even with relatively small axial displacements of the worm and gear and relatively low axial loads, a small wedge angle allows for a high normal force to be generated between the opposing contact surfaces of the frictional connection, resulting in high friction and correspondingly secure self-locking. Furthermore, the thread teeth are securely clamped in the tooth gap without generating large outward radial forces that could cause the worm to disengage.

[0025] Additionally or alternatively, the depth of the tooth gap can be at least partially reduced in the tooth direction. The tooth gap depth is defined by the radial distance between the radially outward-pointing tooth tips of the teeth and the tooth gap base or bottom, which delimits the tooth gap in the radially inward direction. Due to the displacement described herein, frictional contact occurs between the radial contact surfaces of the thread teeth and the toothing, thereby increasing the self-locking effect.

[0026] In order to reduce the depth of the tooth groove, a radially protruding wedge-shaped portion can be provided on the tooth groove. The wedge-shaped portion can protrude outward from the bottom of the tooth groove.

[0027] Width and depth can be used alone or in combination to form a wedge shape.

[0028] The wedge shape of the tooth gaps can be linear, continuous or partially linear, or have a curved profile, continuous or partially curved. The configuration and profile of the wedge shape allow the friction to be adapted in a defined manner to the axial displacement or load. Using a small wedge angle, higher clamping and friction forces can be generated at lower relative loads on the gear and worm.

[0029] The tooth gap may have an axial end face. This axial end face defines the tooth gap in the tooth direction. To this end, it extends at least partially across the open groove or groove cross section of the tooth gap. Preferably, the end face extends across the entire open cross section of the tooth gap. This offers the following advantages: in the event of a collision, the worm contacts the end face during relative displacement of the gear and worm, and the resulting frictional connection enhances the self-locking effect. Furthermore, the flange provides an end stop, preventing the worm from disengaging in the tooth direction during displacement.

[0030] The gear may have a flange element axially defining the toothing. For example, the flange element may be configured as a disc and axially connected to the toothing at the end face. Preferably, the flange diameter of the flange element matches the toothing diameter, measured at the radially outwardly pointing tooth tips. Since the flange diameter is greater than or equal to the toothing diameter, the end face formed on the flange element can partially, and preferably completely, close the open cross-section of the tooth groove on one side of the end face.

[0031] Preferably, the gear has an integral toothing. This toothing may include teeth, tooth gaps, and, if necessary, a flange element. For example, it may be provided as a casting or similar component, produced in a suitable manner. The toothing is preferably integrally connected to the spindle nut or threaded spindle.

[0032] The gear preferably comprises plastic. Preferably, the gear is at least partially made of a thermoplastic polymer using an injection molding process. It is particularly advantageous if the tooth gaps are formed from plastic, thereby achieving high running smoothness and low wear. Furthermore, the gear is preferably injection molded onto a metal core, such as a metal spindle nut.

[0033] A steering column for a motor vehicle includes at least two mutually adjustable components, between which an adjustment drive is arranged. According to the present invention, the adjustment drive is configured according to one or a combination of the aforementioned designs. The adjustment drive can exert an adjustment force on the structural element in an adjustment direction determined by the direction of the spindle axis. The structural element can include at least a load-bearing unit and an actuating unit, which are mutually adjustable in the longitudinal and / or vertical direction.

[0034] The advantage of using one or more adjustment drives according to the invention is that, in the event of a collision, the steering column retains its current adjustment state even under extreme external loads and does not undergo uncontrolled deformation, thereby ensuring optimal operating conditions of the safety system, in particular the energy absorption device arranged between the actuating unit and the carrier unit.

[0035] Preferably, the steering column has a load-bearing unit that can be connected to the vehicle body, which supports the actuating unit, in which the steering spindle is rotatably mounted and is equipped with an adjustment drive device, which includes a threaded spindle that engages with the spindle nut via an external thread, and a drive unit coupled to the threaded spindle or the spindle nut. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The advantageous embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. In the drawings:

[0037] Figure 1 shows a schematic perspective view of a steering column according to the invention,

[0038] Figure 2 yes Figure 1 A further perspective view of the steering column according to the invention from another viewing angle,

[0039] Figure 3 yes Figure 1 and Figure 2 A schematic sectional view of the adjustment drive of the steering column according to the invention is shown,

[0040] Figure 4 Shows Figure 3 A perspective view of a gear of an adjustment drive according to the invention,

[0041] Figure 5 An axial view of a gear according to a second design of the invention is shown,

[0042] Figure 6 yes Figure 5 Axial view of the gears shown in the opposite direction,

[0043] Figure 7 yes Figure 5 and Figure 6 A perspective view of the gears in the middle.

[0044] Figure 8 yes Figure 5 and Figure 6 Another perspective view of the gear in the middle. DETAILED DESCRIPTION

[0045] In the various figures, identical components are always provided with the same reference symbols, so each component is usually only referenced or mentioned once.

[0046] Figure 1 The steering column 1 according to the invention is shown in a schematic perspective view from the upper left obliquely towards the rear end in the direction of travel of a vehicle (not shown), wherein a steering wheel (not shown here) is fixed to the operating area. Figure 2 The steering column 1 is shown viewed from the opposite side, ie from the upper right.

[0047] The steering column 1 comprises a carrier unit 2 having fastening means 21 in the form of fastening holes for connection to a vehicle body (not shown). The carrier unit 2 supports an actuating unit 3 which is mounted in a housing unit 4, also referred to as a guide box or box-section swing arm.

[0048] The actuating unit 3 has a sleeve 31 in which a steering spindle 32 is mounted, which can extend axially around a longitudinal direction, i.e., a longitudinal axis L. A fastening portion 33 is formed at the rear end of the steering spindle 32 to which a steering wheel (not shown) can be fixed.

[0049] In order to achieve longitudinal adjustment, the actuating unit 3 is installed in the housing unit 4 so that it can be telescopically moved in the direction of the longitudinal axis L, so that the steering wheel connected to the steering spindle 32 can be positioned forward and backward relative to the supporting unit 2 in the longitudinal direction, as indicated by the double arrow parallel to the longitudinal axis L.

[0050] The housing unit 4 is mounted in a pivot bearing 22 on the carrier unit 2 and is pivotable about a horizontal pivot axis S, which is transverse to the longitudinal axis L. In the rear region, the housing unit 4 is connected to the carrier unit 2 via an actuating lever 41. By rotating the actuating lever 41 using the illustrated actuator drive 6 (see FIG. 2 ), the housing unit 4 can be rotated relative to the carrier unit 2 about the horizontal pivot axis S in the mounted state, thereby allowing adjustment of the steering wheel connected to the fastening portion 33 in the vertical direction H, as indicated by the double arrow.

[0051] The first adjustment drive 5 serves for longitudinal adjustment of the actuating unit 3 relative to the housing unit 4 in the direction of the longitudinal axis L and comprises a spindle drive having a spindle nut 51 with an internal thread 74 extending along an axis G—the threaded spindle axis—and a threaded spindle 52 meshing with this internal thread, i.e., its external thread is screwed into a corresponding internal thread 74 of the spindle nut 51. The axis G—the threaded spindle axis of the threaded spindle 52—is essentially parallel to the longitudinal axis L.

[0052] The spindle nut 51 is mounted in a bearing housing 53, which is fixedly connected to the housing unit 4 so as to be rotatable about the axis G. In the direction of the axis G, the spindle nut 51 is axially supported on the housing unit 4 by the bearing housing 53. Therefore, the adjustment drive 5 is a so-called immersed spindle drive.

[0053] The axis G defines the adjustment direction of the adjustment drive 5. The axial direction mentioned below in relation to the adjustment drive 5 is consistent with the direction of the axis A.

[0054] By means of a fastening element 54 formed at its rear end, the threaded spindle 52 is connected to the actuating unit 3 via the transmission element 34 , specifically so that it is fixed in the direction of the axis G or longitudinal axis L and remains stationary in rotation relative to the axis G. The rotatably drivable spindle nut 51 and the rotationally fixed threaded spindle 52 together form a so-called immersed spindle drive.

[0055] The transmission element 34 extends from the actuating unit 3 through a slot-shaped passage opening 42 on the housing unit 4. In order to adjust the steering column 1 in the longitudinal direction, the transmission element 34 can be freely moved in the passage opening 42 in the longitudinal direction.

[0056] The adjustment drive 5 comprises an electric motor 55, which can be used to drive the spindle nut 51 to rotate relative to the stationary threaded spindle 52 along the axis G. Therefore, depending on the direction of rotation of the drive motor 55, the threaded spindle 52 can be translated relative to the spindle nut 51 in the direction of the axis G, so that the actuating unit 3 connected to the threaded spindle 52 is adjusted relative to the housing unit 4 connected to the spindle nut 51 in the direction of the longitudinal axis L.

[0057] Figure 2 It is from Figure 1 The perspective view of the steering column 1 from the rear side shows how the second adjustment drive 6 is connected to the steering column 1 for adjustment in the vertical direction H. This adjustment drive 6 comprises a spindle nut 61, with a threaded spindle 52 engaging its internal thread 74 in the direction of axis G. The threaded spindle 52 is mounted in a bearing housing 63, which is fixed to the housing unit 4 so as to be rotatable about axis G and axially supported on the housing unit 4 in the direction of axis G. The threaded spindle 52 can be driven by an electric drive motor 65 and can be selectively driven for rotation in both directions about axis G. Therefore, this adjustment drive 6 is a so-called rotating spindle drive.

[0058] The spindle nut 61 can be made of plastic or non-ferrous metal (such as brass or similar material). It is fixedly mounted on one end of the double-arm actuator rod 41 so that it remains stationary relative to the rotation around the axis G. The actuator rod 41 is mounted on the carrying unit 2 so that it can rotate around the pivot bearing 23, and its other end is connected to the housing unit 4.

[0059] By rotating the threaded spindle 62 - depending on the direction of rotation of the drive motor 65, the spindle nut 61 can be translated relative to the threaded spindle 62 in the direction of the axis G, so that the housing unit 4, which is connected to the spindle nut 61 via the actuating rod 41, and the actuating device 3 therein can be adjusted upward or downward in the vertical direction H relative to the supporting unit 2, as indicated by the double arrow.

[0060] Figure 3 A separate sectional view of the actuating drive 5 is shown as an immersed spindle drive, with the bearing housing 53 omitted for greater clarity. Figure 5 shows a longitudinal section along the spindle axis G, Figure 6 This is an enlarged detail picture.

[0061] The adjustment drive 5 has a gear wheel 7 or a toothed wheel 7 comprising a hub element 71 (=hub) having a spindle nut 51 with an internal thread 511 and arranged here coaxially with the spindle axis G. However, it is also conceivable for the spindle nut 51 to be made of a metallic material and for the hub element 71 to be made of plastic and to be formed using a plastic injection molding process.

[0062] Figure 4 A perspective sectional view of a first design of a gear wheel 7 is shown. On its outer side, it has a toothing 72 coaxial with a hub element 71. It is configured as a helical gear toothing with a plurality of radially outwardly projecting teeth 73, between which tooth gaps 74 are arranged in the circumferential direction. The teeth 73 and the corresponding tooth gaps 74 extend in a toothing direction Z, oblique to the axis G.

[0063] The worm 56 is connected to the motor shaft of the motor 55 and can be driven to rotate around its worm axis W. The worm axis W is arranged transversely, preferably perpendicular to the axis G.

[0064] The worm 56 has worm teeth 57 extending along its helix and meshing with the tooth grooves 74 of the toothed portion 72 to form a gearing engagement.

[0065] Each tooth gap 74 has a gap width A measured approximately in the circumferential direction, in particular perpendicularly to the tooth direction Z. The gap width A corresponds to the distance from the tooth flank of the worm tooth 57 of the worm 56 in the meshing state.

[0066] According to the present invention, the groove width A decreases along the tooth direction Z, so that the tooth groove 74 gradually changes into a wedge shape when viewed from the tooth direction Z. Figure 4 In the embodiment, the groove width A at the end facing the observer is greater than that at the end away from the observer.

[0067] In the event of a collision, if a person strikes the steering wheel, a high collision force F will act on the adjustment drive 5 via the steering spindle 32 and the sleeve 31. Figure 3 As can be seen in the figure, the impact force F is transmitted to gear 7 via the threaded spindle 52 in the axial direction of axis G. Gear 7 is displaced axially relative to worm 56 in the direction of the impact force F, perpendicular to worm axis W. At this time, worm teeth 57 move along tooth grooves 54 in tooth direction Z. Because the groove width A gradually narrows in this tooth direction Z until it becomes smaller than the width of worm teeth 57, when gear 7 is displaced relative to worm 56, worm teeth 57 are wedged into tooth grooves 74 between the flanks of teeth 73 and secured by friction. This increases gear friction, and the worm gear enters a self-locking state.

[0068] Figures 5 to 8 Various views of a second design of a gear wheel 7 according to the invention are shown, in particular Figure 5 Axial end view along the direction of collision force F and Figure 6 Axial end view in opposite directions. Figure 7 and Figure 8 A perspective view is shown.

[0069] It's obvious. Figure 5 The slot width A ratio Figure 6That is, according to the present invention, the groove width A gradually changes in a wedge shape in the tooth direction Z.

[0070] In the second embodiment, the gear 7 has a flange 75 that is axially formed on the tooth in the region of the reduced slot width A. As shown in the example, the diameter of the flange 75 can be approximately equal to the diameter of the gear 7, measured along the tooth tip of the tooth 73. The tooth gap 74 is thus axially closed in the tooth direction Z.

[0071] During the displacement, the worm 56 with the worm teeth 57 may hit the flange 75, thereby increasing the friction. In addition, the flange 75 also acts as an end stop, which prevents the worm 56 from disengaging from the gear meshing during the displacement.

[0072] Reference numerals list: 1 steering column

[0073] 2 load-bearing units

[0074] 21 Fastening device

[0075] 22, 23 pivot bearing 3 actuating unit

[0076] 31 casing

[0077] 32 steering spindle

[0078] 33 Fastening part

[0079] 34 transmission elements

[0080] 4 Shell elements

[0081] 41 Actuating rod

[0082] Channel 42

[0083] 5,6 Adjustment drive device 51,61 Spindle nut 511 Internal thread

[0084] 52, 62 threaded spindle 53, 63 bearing housing 54 fastening element

[0085] 55, 65 motors

[0086] 56, 66 worm gear

[0087] 57 worm teeth

[0088] 7 gears

[0089] 71 wheel hub components

[0090] 72 teeth

[0091] 73 teeth

[0092] 74 tooth grooves

[0093] 75 flange

[0094] L longitudinal axis

[0095] H vertical direction

[0096] G spindle axis (thread spindle axis)

[0097] W worm shaft

[0098] Z tooth direction

[0099] A slot width.

Claims

1. An adjustment drive device (5) for a steering column (1) of a motor vehicle, comprising a threaded spindle (52) extending axially in the direction of a spindle axis (G) and meshing with a spindle nut (51), and a drive unit (55) by which the threaded spindle (52) and the spindle nut (51) are driven in relative rotation; The drive unit (55) has a gear mechanism comprising a worm (56) which is rotatable about a worm axis (W) transverse to the spindle axis (G), and a worm thread (57) of the worm meshing with a toothed portion (72) of a gear (7) connected coaxially to the threaded spindle (52) or the spindle nut (51), wherein: The thread teeth (57) of the worm screw thread mesh with the tooth groove (74) between two adjacent teeth (73) of the tooth portion (72) of the gear (7). A locking device is provided which can be placed in a locking position in order to fix the threaded spindle (52) relative to the spindle nut (51). It is characterized in that The gear (7) and the worm (56) are capable of relative movement in the direction of the spindle axis (G), and the tooth portion (72) and the worm thread are designed to convert relative axial displacement into a reduction in the tooth gap between the gear (72) and the worm (56).

2. The adjustment drive device according to claim 1, characterized in that A triggering threshold is formed between the gear (7) and the worm (56).

3. The adjustment drive device according to any of the preceding claims, characterized in that Each tooth gap (74) is at least partially narrowed in a wedge shape in the tooth direction (Z).

4. The adjustment drive device according to claim 3, characterized in that The width of the tooth gap (74) decreases at least partially in the tooth direction (Z).

5. The adjustment drive device according to any one of claims 3 or 4, characterized in that: The depth of the tooth groove (74) decreases at least partially in the tooth direction (Z).

6. The adjustment drive device according to claim 5, characterized in that The tooth groove (74) has a radially protruding wedge-shaped portion.

7. The adjustment drive according to any of the preceding claims, characterized in that The tooth groove (74) has an axial end surface.

8. The adjustment drive according to any one of the preceding claims, characterized in that The gear (7) has a flange element (75) which defines a toothed portion (72) in the axial direction.

9. The adjustment drive according to any of the preceding claims, characterized in that The gear (7) has an integrally formed tooth component.

10. The adjustment drive according to any of the preceding claims, characterized in that The gear (7) is made of plastic.

11. A steering column (1) for a motor vehicle, comprising at least two parts (2, 3, 31) which are adjustable relative to one another, between which an adjustment drive (5, 6) is arranged. It is characterized in that The adjusting drive (5, 6) is configured according to any one of the preceding claims 1 to 10.

12. The steering column according to claim 11, characterized in that It comprises a carrier unit (2) which can be mounted on a vehicle body and which supports an actuating unit (3), wherein a steering spindle (37) is rotatably mounted in the actuating unit (3) and comprises an adjustment drive (5, 6), which comprises a threaded spindle (52, 62) which engages in a spindle nut (51, 61) via an external thread, and a drive unit (55, 65) which is coupled to the threaded spindle (52, 62) or the spindle thread (51, 61) such that the threaded spindle (52, 62) and the spindle nut (51, 61) can rotate relative to each other, wherein the adjustment drive (5, 6) is connected to the carrier unit (2) or the actuating unit (3).

13. The steering column according to claim 11 or 12, characterized in that An energy absorption device is connected between the carrying unit (2) and the actuating unit (3).

Images