ADJUSTING DRIVE FOR A STEERING COLUMN AND STEERING COLUMN FOR A MOTOR VEHICLE

Description

State of the art

[0001] The invention relates to an adjustment drive for a motor-adjustable steering column for a motor vehicle, comprising a threaded spindle having an axis engaging a spindle nut, and a drive unit with a belt drive having a belt that can be driven by a motor and runs around a circumferential belt running surface of a belt pulley that is connected in a rotationally fixed manner to the spindle nut or the threaded spindle. The belt pulley is rotatably mounted about the axis in a bearing arrangement that has at least one bearing ring axially attached to the belt pulley. A steering column with at least one such adjustment drive is also subject of the invention.

[0002] Steering columns for motor vehicles have a steering shaft with a steering spindle. At the rear end in the direction of travel, closest to the driver, a steering wheel is attached to which the driver can initiate steering commands. The steering spindle is mounted so that it can rotate about its longitudinal axis in an actuating unit which is held on the vehicle body by a support unit. Because the actuating unit is held in a casing unit connected to the support unit, also known as a guide box or box swing arm, and is telescopically movable in the direction of the longitudinal axis, longitudinal adjustment is possible. Height adjustment can be achieved by mounting the actuating unit, or a casing unit holding it, on the support unit so that it can pivot in the height direction. The adjustment of the actuating unit in the longitudinal or vertical direction is possible.Height direction allows the adjustment of an ergonomically comfortable steering wheel position relative to the driver's position in the operating position, also known as the driving or operating position, in which manual steering intervention can take place.

[0003] It is known in the art to provide a motorized adjustment drive with a drive unit for adjusting the actuating unit relative to the support unit. The drive unit comprises an electric motor connected - usually via a gear - to a spindle drive comprising a threaded spindle screwed into a spindle nut. The drive unit drives the threaded spindle and the spindle nut in rotation relative to one another about the threaded spindle axis, whereby the threaded spindle and the spindle nut can be moved translationally towards or away from one another depending on the direction of rotation. In one embodiment, the threaded spindle can be driven in rotation by the drive unit, which is fixedly connected to the actuating unit or the support unit, and engages the spindle nut, which is fixedly attached to the support unit or alternatively to the actuating unit with respect to rotation about the threaded spindle axis.In the direction of the threaded spindle axis, the threaded spindle rests on the support unit or the adjusting unit, and the spindle nut rests on the adjusting unit or alternatively on the support unit, so that a rotary drive of the threaded spindle causes a translational adjustment of the support unit and the adjusting unit relative to each other in the direction of the threaded spindle axis. This design is therefore also referred to as a rotary spindle drive.

[0004] In an alternative embodiment, the threaded spindle is non-rotatably coupled to the support unit or, alternatively, to the actuating unit with respect to rotation about its threaded spindle axis, and the spindle nut is rotatable but fixed in the direction of the threaded spindle axis, correspondingly mounted on the actuating unit or, alternatively, on the support unit. As in the first embodiment, the threaded spindle is supported on the support unit or, alternatively, on the actuating unit in the direction of the threaded spindle axis, and the spindle nut is supported accordingly on the actuating unit or, alternatively, on the support unit, so that the threaded spindle can be translated in the direction of the threaded spindle axis by the spindle nut being driven in rotation by the drive unit. This design is referred to as a plunger spindle drive.

[0005] As with the first-mentioned design, the rotary drive of the threaded spindle enables a translational adjustment of the support unit and the actuating unit relative to each other in the direction of the threaded spindle axis. In both designs, the spindle drive forms a motorized adjustment drive acting between the support unit and the actuating unit, allowing the actuating unit to be adjusted relative to the support unit.

[0006] To achieve longitudinal adjustment of the actuating unit along the longitudinal axis of the steering spindle, the spindle drive of an adjustment drive can be arranged between the actuating unit and a casing unit, also called a guide box or box rocker, which accommodates the actuating unit in an axially longitudinally displaceable manner and is connected to the support unit. The threaded spindle axis can be aligned substantially parallel to the longitudinal axis. For height adjustment, a spindle drive can be arranged between the support unit and a vertically pivotable actuating unit or casing unit in which the actuating unit is accommodated. Motorized longitudinal and height adjustment can be implemented individually or in combination on a steering column.

[0007] In an adjustment drive of the type mentioned above, the spindle drive is driven via a belt drive in which a drive wheel designed as a belt pulley can be rotated by the motor. This drive wheel is coupled via a rotating belt to a belt wheel which, depending on the design of the spindle drive, is connected in a rotationally fixed manner to the spindle nut or to the threaded spindle. The belt wheel has an externally rotating belt running surface which, in the case of a toothed belt drive, can have teeth. In the prior art, such an adjustment drive is described, for example, in DE 10 2017 218 894 A1. A fundamental advantage of the belt drive is its smooth running and relatively low weight. During operation, however, transverse forces can occur, for example due to load changes, which can potentially impair the operating behavior.

[0008] An adjustment drive of the type mentioned above is known from US 2015 / 0183455 A1. In view of this, it is an object of the present invention to enable improved operating behavior in a belt-driven motorized adjustment drive and to be able to optimize the operating behavior of a steering column with such an adjustment drive. Description of the invention

[0009] This object is achieved according to the invention by the adjustment drive having the features of claim 1 and the steering column according to claim 10. Advantageous further developments emerge from the subclaims.

[0010] In an adjustment drive for a motor-adjustable steering column for a motor vehicle, comprising a threaded spindle having an axis engaging in a spindle nut, and a drive unit with a belt drive having a belt that can be driven in rotation by a motor and runs around a circumferential belt running surface of a belt pulley that is connected in a rotationally fixed manner to the spindle nut or the threaded spindle, which belt pulley is rotatably mounted about the axis in a bearing arrangement that has at least one bearing ring attached axially to the belt pulley, the invention provides that the bearing ring has a flanged disk section that projects radially beyond the belt running surface and limits the width of the belt running surface.

[0011] The belt wheel is also referred to as a pulley in the following.

[0012] An axial bearing ring according to the invention enables optimized support of the axial bearing forces exerted on the pulley via the threaded spindle during operation, for example by transferring the axial forces acting on the pulley to an axial abutment, which is attached or designed, for example, as an outer bearing ring on or in a bearing housing. This bearing housing can provide axial support for the spindle nut or the threaded spindle driven by the motor. Depending on the design of the bearing arrangement, the bearing ring can be optimized in terms of its dimensions and material to ensure smooth rotation of the pulley and, at the same time, enable low bearing play with an optimized support and bearing geometry.In this way, improved running smoothness, especially during load changes that occur during operation, and low wear can be achieved, which can lead to improved long-term operating behavior.

[0013] In addition, the flanged pulley section which projects radially, i.e. outwards with respect to the axis, beyond the belt running surface, forms a lateral limitation of the belt running surface, in other words a defined axial limitation of the possible lateral movement of the belt on the belt running surface. With respect to the belt running surface, the flanged pulley section preferably projects outwards in a stepped manner and, in other words, has a larger outer diameter than the smallest diameter of the belt running surface. The flanged pulley section thus has, at least over a partial circumferential area, preferably continuously over the entire circumference, an axial stop surface or axial surface directed against the axial position of the belt running surface. This clearly defines the axial area in which the belt can move in the axial direction relative to the belt pulley during operation, i.e.in which it can move laterally perpendicular to its direction of rotation until it hits the stop surface of the flanged pulley section. If the belt moves towards the lateral, axial edge of the belt running surface after a large number of revolutions during operation, for example when adjusting the steering column over the full adjustment range, it is safely guided laterally by a stop (running into) the flanged pulley section and held on the belt running surface. In other words, the width of the belt running surface measured in the axial direction can be clearly limited and defined by the flanged pulley section. This can prevent excessive skew of the belt and reduce adverse friction, which enables increased smoothness and less wear, thus improving overall operating behavior.

[0014] One advantage of the invention is that the bearing ring serves a dual function of optimizing the bearing support of the pulley and optimizing the belt guidance on the pulley. This enables a functional improvement with minimal design effort, compact dimensions, and low weight.

[0015] Preferably, the flanged pulley section can be designed as a continuous annular disk-shaped flanged pulley which has a larger outer diameter than the belt running surface.

[0016] In an advantageous embodiment, two bearing rings can be arranged axially on either side of the belt running surface. For this purpose, one of the two bearing rings can be arranged on the end face of the belt pulley. As a result, the belt running surface is located between the stop surfaces of the flanged pulley sections, which are opposite one another in the axial direction and protrude radially beyond the belt running surface. In this way, the width of the belt running surface is limited, measured between the axial stop surfaces of the flanged pulleys. By adapting the width of the belt running surface to the belt width with minimal lateral play, optimized guidance of the belt during operation can be achieved, advantageously reducing unwanted noise and wear.

[0017] It is advantageous for the belt pulley (belt wheel) to have circumferential teeth, over which the flanged pulley section protrudes radially. The belt drive is designed as a toothed belt drive, and accordingly, the belt is designed as a toothed belt and the pulley as a corresponding toothed belt pulley. The toothed belt drive enables low-slip and smooth torque transmission from a drive wheel coupled to the motor shaft of the electric motor to the belt wheel according to the invention, which, like the drive wheel, is designed as a toothed belt wheel. The flanged pulley sections according to the invention guide the toothed belt securely on the toothed belt running surface, thereby increasing smoothness and reducing friction and wear.

[0018] The bearing arrangement can preferably be formed between the belt pulley and a bearing housing. The spindle nut or the threaded spindle together with the belt pulley is rotatably mounted in the bearing housing. The bearing housing can be a drive housing of the belt drive or form a part thereof to which the motor is attached. Furthermore, the bearing housing can be designed for attaching the adjustment drive to the steering column. The bearing rings, which are preferably arranged on both axial end faces of the belt pulley, can be axially supported and rotatably mounted with their axial outer sides against corresponding end-face bearing surfaces of outer bearing rings, which are attached to the bearing housing. Because the belt pulley is supported against the outer bearing rings in both axial directions via the bearing rings, a smooth-running bearing arrangement with low bearing play can be achieved.The belt is guided through the flanged pulley sections and kept at a distance from the bearing surfaces and other internal surfaces of the bearing housing, so that smooth running is advantageously increased and friction and wear are reduced at the same time.

[0019] An advantageous embodiment can provide for the bearing arrangement to comprise a rolling bearing, with the bearing ring being designed as the raceway of the rolling bearing. In order to realize the known advantages of a rolling bearing, such as smooth running with low wear, rolling elements, for example balls or rollers, can be arranged between bearing rings, preferably arranged on both sides of the belt pulley, and corresponding outer bearing rings of the bearing housing. A bearing ring according to the invention has a rolling element raceway, for example a ball raceway, on its outer end face facing the belt pulley, and a stop surface for limiting the belt running surface on its end face facing the belt pulley. As a result, the bearing ring in this embodiment has a dual function as part of a rolling bearing and as a flanged pulley for guiding the belt, which enables a compact design with relatively low design and manufacturing effort.

[0020] The rolling bearings can preferably be designed as angular contact bearings, in which the rolling surfaces of the rolling elements - for example, the approximately point-like contact surfaces of balls - on the bearing and outer bearing ring each lie on a connecting line that is oblique to the axis. Such angular contact bearings enable low-backlash and robust bearings while simultaneously absorbing axial and radial loads. The rolling bearings arranged on either side of the belt pulley can form an X arrangement, in which the intersection points of the connecting lines with the axis are located between the bearings, or an O arrangement, in which the intersection points of the connecting lines with the axis are located outside the bearing arrangement. The inventive advantages of optimized belt guidance through the flanged pulley sections can be realized equally advantageously in the different bearing arrangements.

[0021] It is possible for the belt pulley to have a hub body to which at least one bearing ring is connected. The hub body preferably comprises the belt running surface. In a submersible spindle drive, the hub body has the internal thread of the spindle nut, which can be formed as a single piece or in an inserted or externally mounted threaded bushing. In a rotary spindle drive, the hub body is axially and rotationally fixedly connected to the threaded spindle, for example, by a single piece or by a rotationally fixed connection.

[0022] In an advantageous embodiment, the bearing ring(s) and the hub body can be made of different materials. This allows the material properties to be optimally adapted to the specific loads and requirements during operation. For this purpose, the bearing ring(s) and hub body can initially be manufactured separately, preferably from different materials, and then joined together using suitable joining processes. This allows for further optimization of the operating properties.

[0023] It can be advantageous for the hub body to be made of a plastic and / or metal. A plastic material, such as a thermoplastic polymer, enables efficient production using plastic injection molding, allowing for considerable design freedom and low weight. External toothing can be integrated as the running surface of a timing belt with little effort, and the material properties of the plastic can be tailored to the belt in order to optimize running characteristics and wear, particularly in a timing belt drive. Furthermore, the hub body can be efficiently connected to a threaded spindle by injection molding, or to an inserted threaded bushing of a spindle nut. Alternatively, it is also conceivable to integrate the internal thread of the spindle nut into the plastic of the injection-molded part.Alternatively, the hub body can be formed at least partially from a metallic material, for example, as a pressed or die-cast part, such as aluminum, magnesium, or non-ferrous metal alloys or the like. A composite construction made of plastic and metallic materials is also possible to combine the advantageous properties of the different materials.

[0024] It can advantageously be provided that the bearing ring comprises a sheet metal part. A bearing ring can, for example, be efficiently manufactured as a press-stamped part from sheet steel or another, preferably metallic, material that has greater strength and / or hardness than the material of the hub body. This enables a space-saving, yet resilient, and low-wear design, which is also well suited, for example, for the formation of a rolling bearing bearing ring.

[0025] Separately provided bearing rings can preferably be attached axially to the end faces of a hub body on both sides, preferably by means of a permanent connection. This can, for example, comprise a positive connection, and additionally or alternatively a material connection, such as a welded or adhesive connection. It is also conceivable and possible to injection-mold a plastic hub body onto the bearing rings.

[0026] It is possible to provide a sensor device for detecting the rotation of the pulley. The sensor device can comprise an electronic sensor arrangement, for example an absolute value or incremental sensor, which preferably operates according to a contactless measuring method, for example optical, inductive, capacitive or the like. The bearing ring preferably has a sensor arrangement so that the angle of rotation can be detected by means of a sensor arranged fixedly relative to the adjustment drive. This makes it possible to measure and monitor the rotation of the spindle nut or the threaded spindle, so that the adjustment path of the spindle drive can be determined. Operation can also be monitored, for example by detecting a damaged toothed belt or a blockage.

[0027] In an advantageous development, the bearing ring can be partially magnetized around its circumference so that the sensor arrangement, for example, a Hall sensor, can detect this. Preferably, the magnetization is provided in the flange section. In this case, magnetized areas alternate with unmagnetized areas in the circumferential direction relative to the axis of the threaded spindle. Alternatively, magnetized north pole areas alternate with magnetized south pole areas in the circumferential direction relative to the axis of the threaded spindle.

[0028] Alternatively or additionally, the bearing ring, preferably in the flanged portion, can have openings or recesses distributed around the circumference, which are detected by the sensor arrangement. The openings or recesses are preferably arranged evenly around the circumference relative to the axis of the threaded spindle. In other words, the bearing ring forms a type of perforated disk that can be detected by an optical sensor. As an alternative to openings or recesses, the bearing ring, preferably its flanged portion, can have regions distributed around the circumference that have different reflective properties. These form a type of pattern that can be detected by the sensor arrangement.

[0029] Preferably, the sensor array is connected to a control unit, which evaluates and further processes the measured values ​​provided by the sensor array and preferably forwards them to other components. Preferably, the sensor array is connected to the same power supply as the adjustment drive. This is cost-effective and eliminates the need for additional cabling.

[0030] Preferably, at least two sensor devices, preferably operating according to different measuring principles, can be provided. This allows for a redundant measuring arrangement, which increases operational reliability and reliability and can also potentially enable greater measurement accuracy.

[0031] Furthermore, the invention relates to a motor-adjustable steering column for a motor vehicle, comprising a support unit which can be attached to a vehicle body and which holds an adjusting unit in which a steering spindle is mounted rotatably about a longitudinal axis, and comprising an adjusting drive which is connected to the support unit and to the adjusting unit and by which the adjusting unit is adjustable relative to the support unit, wherein the adjusting drive comprises a threaded spindle having an axis which engages in a spindle nut, and a drive unit comprising a belt drive which has a belt which can be driven in rotation by a motor and which runs around a circumferential belt running surface of a belt pulley which is connected in a rotationally fixed manner to the spindle nut or the threaded spindle and which is mounted rotatably about the axis in a bearing arrangement, wherein the invention providesthat the adjustment drive is designed according to one of the previously described embodiments or combinations thereof.,

[0032] The steering column can be provided with an adjustment drive according to the invention for longitudinal adjustment and, in addition or alternatively, for height adjustment. This allows the steering column to be adjusted smoothly and reliably, and a relatively low weight can be achieved. Description of the drawings

[0033] Advantageous embodiments of the invention are explained in more detail below with reference to the drawings. In detail: Figure 1 shows a schematic perspective view of an electrically adjustable steering column according to the invention; Figure 2 shows the steering column according to Figure 1 in a further perspective view; Figure 3 shows an adjustment drive according to the invention in a schematic perspective view, Figure 4 shows a cross section AA through the adjustment drive according to Figure 3 , Figure 5 a longitudinal section through an adjustment drive according to Figure 3 , Figure 6 a longitudinal section through an adjustment drive according to Figure 3 in a second embodiment, Figure 7 shows a longitudinal section through an adjustment drive according to the invention in a third embodiment. Embodiments of the invention

[0034] In the various figures, identical parts are always provided with the same reference symbols and are therefore usually named or mentioned only once.

[0035] Figure 1 shows a steering column 1 according to the invention in a schematic perspective view from above obliquely towards the rear end, based on the direction of travel of a vehicle not shown, where a steering wheel not shown here is held in the operating area. Figure 2 shows the same steering column 1 in a view from below.

[0036] The steering column 1 comprises a support unit 2, which is designed as a console and has fastening means 21 in the form of mounting holes for attachment to a vehicle body (not shown). The support unit 2 holds an actuating unit 3, which is housed in a casing unit 4—also referred to as a guide box or box-type rocker arm.

[0037] The actuating unit 3 has a casing tube 31 in which a steering spindle 32 is rotatably mounted about a longitudinal axis L, which extends axially in the longitudinal direction, i.e., in the direction of the longitudinal axis L. At the rear end, a fastening section 33 is formed on the steering spindle 32, to which a steering wheel (not shown) can be attached. At the front end, the steering spindle 32 is torque-locked to a fork 351 of a universal joint 35.

[0038] The actuating unit 3 is accommodated in the casing unit 4 in a telescopically displaceable manner in the direction of the longitudinal axis L in order to realize a longitudinal adjustment in order to be able to position the steering wheel connected to the steering spindle 32 forwards and backwards in the longitudinal direction relative to the support unit 2, as indicated by the double arrow parallel to the longitudinal axis L.

[0039] A first adjustment drive 5 for the longitudinal adjustment of the actuating unit 3 relative to the casing unit 4 in the direction of the longitudinal axis L has a spindle drive with a spindle nut 51 with an internal thread, into which a threaded spindle 52, also referred to as spindle 52 for short, extends along a threaded spindle axis G, also referred to as axis G for short, engages, i.e., is screwed with its external thread into the corresponding internal thread of the spindle nut 51. The axis G of the threaded spindle 52 runs essentially parallel to the longitudinal axis L.

[0040] The spindle nut 51 is mounted in a bearing housing 81 of a gear 8, which is fixedly connected to the casing unit 4, for rotation about the axis G. In the direction of the axis G, the spindle nut 51 is axially supported on the casing unit 4 via the bearing housing 81, as will be explained in more detail below.

[0041] The threaded spindle 52 is connected to the actuating unit 3 by means of a fastening element 54 formed at its rear end via a transmission element 34, namely fixedly in the axial direction, i.e. in the direction of the axis G or the longitudinal axis L and fixed with respect to rotation about the axis G. A so-called submersible spindle drive is realized by the rotationally drivable spindle nut 51 and the threaded spindle 52 which is fixed with respect to rotation about the axis G.

[0042] How Figure 2can be removed, the transmission element 34 extends from the actuating unit 3 through a slot-shaped through opening 42 in the casing unit 4. In order to adjust the steering column 1 in the longitudinal direction, the transmission element 34 can be moved freely in the through opening 42 in the longitudinal direction.

[0043] The adjustment drive 5 has an electric motor 55, which drives the spindle nut 51 in rotation relative to the fixed threaded spindle 52 with respect to the axis G. Depending on the direction of rotation of the motor 55, the threaded spindle 52 can be displaced translationally relative to the spindle nut 51 in the direction of the axis G, so that the adjusting device 3 connected to the threaded spindle 52 is correspondingly adjusted relative to the casing unit 4 connected to the spindle nut 51 in the direction of the longitudinal axis L. The drive of the spindle nut 51 will be explained in more detail below.

[0044] In Figure 2It can also be seen how a second adjustment drive 6 for adjustment in the height direction H is attached to the steering column 1. This adjustment drive 6 comprises a spindle nut 61, in whose internal thread 74 a threaded spindle 62 engages along an axis G. The adjustment drive 6 has a gear 9, in which the threaded spindle 62 is mounted in a gear housing 91, which is fastened to the casing unit 4, so as to be rotatable about the axis G and is supported axially, i.e. in the direction of the axis G, on the casing unit 4. The threaded spindle 62 can be driven selectively in both directions of rotation about its axis G by an electric motor 65.

[0045] The spindle nut 61 is fixed with respect to rotation about the axis G at one end of the two-armed adjusting lever 41, which is mounted on the support unit 22 so as to be rotatable about a pivot bearing 23, and whose other arm is connected at the other end to the casing unit 4.

[0046] By rotating the threaded spindle 61 - depending on the direction of rotation of the motor 65 - the spindle nut 61 can be displaced translationally relative to the threaded spindle 62 in the direction of the threaded spindle axis G, so that the casing unit 4 connected to the spindle nut 61 via the adjusting lever 41, together with the adjusting device 3 accommodated therein, can be adjusted up or down in the height direction H relative to the support unit 2, as indicated by the double arrow.

[0047] A so-called rotary spindle drive is realized by the rotating threaded spindle 62 and the spindle nut 61 which is fixed in rotation.

[0048] The present invention relates to an adjustment drive 5, in which the gear 8 for transmitting torque from the motor 55 to the spindle nut 51 is designed according to the invention as a toothed belt drive 8. Such an adjustment drive 5 is detached from the steering column 1 in Figure 3shown in a perspective view, in Figure 4 in a cross section AA through the gear 8 perpendicular to the axis G, and in Figure 5 in a longitudinal section along the axis G. Figure 6 shows a further development of the adjustment drive 5 according to Figure 5 in the same view. In the same view as in Figure 5 is in Figure 7 a modified version is shown, which, in contrast to the one shown in the Figures 4 to 7 The plunger spindle drive shown is designed as a rotary spindle drive similar to the adjustment drive 6.

[0049] The same reference symbols are used for parts with the same function, even for different versions.

[0050] The belt transmission 8 comprises a drive wheel 82 mounted on the motor shaft 56 of the motor 55 and designed as a toothed belt pulley, a belt wheel 83 connected in a rotationally fixed manner to the spindle nut 51 and also designed as a toothed belt pulley, and a toothed belt 84 circulating around the drive wheel 82 and the belt wheel 83. This arrangement is clearly shown in Figure 4 recognizable.

[0051] In the example shown, the spindle nut 51 is integrated with the pulley 83. As in Figure 5 As can be seen, the belt pulley 83 comprises a hub body 85, which is formed integrally with the spindle nut 51 and can, for example, be designed as a plastic injection-molded part. The hub body 85 has an externally circumferential toothing 86, which has a width B axially, measured in the direction of the axis G, and forms the circumferential belt running surface for the toothed belt 84.

[0052] The toothed belt 84 has a width z which is smaller than the width B of the toothing.

[0053] The toothing 86 extends between axial end faces of the hub body 83, with an inventive, annular bearing ring 9 being mounted on each of these end faces. Each bearing ring 9 has a flanged pulley section 91 projecting radially outward from the hub body 85 beyond the toothing 86 and thus beyond the belt running surface. With their axially opposing stop surfaces, the flanged pulley sections 91 delimit the belt running surface on both sides, so that the toothed belt 84 circulating around the hub body 85 is guided between the flanged pulley sections 91. The opposing stop surfaces of the flanged pulley sections 91 have an axial distance equal to the width B of the belt running surface 86.

[0054] On their axial sides located outward relative to the hub body 85, the bearing rings 9 each have a circumferential ball raceway 92. Between the ball raceways 92 and the outer bearing rings 87, which are axially supported relative thereto on the bearing housing 81, balls 88 are arranged as rolling elements, rolling in the circumferential direction. Thus, each bearing ring 9, together with the outer bearing ring 87 and the balls 88, forms a rolling bearing, in this specific example an angular contact ball bearing.

[0055] The bearing rings 9 can be formed as sheet metal parts, preferably as stamped and pressed steel parts. These have sufficient hardness and strength in the area of ​​the ball track 92 to allow the balls 88 to roll.

[0056] The bearing rings 9 can preferably be firmly and non-detachably connected to the hub body 85, for example by welding and / or gluing to the plastic material of the hub body 85.

[0057] The Figure 6The version shown is similar to that in Figure 5 constructed. In addition, the bearing ring 9, arranged on the left in the drawing, has sensor elements 93 distributed around the circumference in the area of ​​its flanged disk section 91, for example, magnetic and / or optical markings or the like. By means of a sensor element 94 fixedly attached to the bearing housing 81, which can comprise, for example, a Hall sensor or an optical sensor or the like, the sensor elements 93 can be metrologically detected in order to detect a rotation of the pulley 83. In this way, a sensor arrangement with a rotation sensor is provided.

[0058] At the Figure 7The embodiment shown is an inventive design of a rotary spindle drive, such as the above-mentioned adjusting drive 6 with its threaded spindle 62 which can be driven in rotation by the motor 65. The toothed belt transmission 8 can be functionally essentially the same as in Figure 5 The difference is that the hub body 85 of the belt pulley 83 is axially and rotationally fixedly connected to the threaded spindle 62, so that the latter can be driven in rotation via the toothed belt drive 8. List of reference symbols

[0059] 1Steering column 2Support unit 21Fasteners 22, 23Pivot bearing 3Adjusting unit 31Steering tube 32Steering spindle 33Fastening section 34Transmission element 4Steering unit 41Adjusting lever 42Through opening 5, 6Adjustment drive 51, 61Spindle nut 52, 62Threaded spindle 54Fastening element 55, 65Motor 56, 66Motor shaft (drive shaft) Worm 8Gearbox (timing belt drive) 81Bearing housing 82Drive wheel 83Belt wheel (pulley) 84Timing belt 85Hub body 86Toothing (belt running surface) 87Outer bearing ring 88Balls 9Bearing ring 91Flanged wheel section 92Ball race LLongitudinal axis GAxis BWidth ZWidth

Claims

1. Adjustment drive (6, 7) for a motor-adjustable steering column (1) for a motor vehicle, comprising a threaded spindle (52, 62) engaging in a spindle nut (51, 61) and having an axle (G), and a drive unit with a belt drive (8) which has a belt (84) which can be driven in rotation by a motor (55, 65), which runs around a circumferential belt running surface (86) of a belt wheel (83) which is non-rotatably connected to the spindle nut (52) or the threaded spindle (62) and which is mounted rotatably about the axis (G) in a bearing arrangement (87, 88, 9) which has at least one bearing ring (9) mounted axially on the belt wheel (83), characterized in in that the bearing ring (9) has a flanged pulley section (91) which projects radially beyond the belt running surface (86) and limits the width of the belt running surface (86).

2. Adjustment drive according to claim 1, characterized in that two bearing rings (9) are arranged axially on both sides of the belt running surface (86).

3. Adjustment drive according to one of the preceding claims, characterized in that the belt pulley (83) has a circumferential toothing (86), over which the flanged pulley section (91) projects radially.

4. Adjustment drive according to one of the preceding claims, characterized in that the bearing arrangement (87, 88, 9) is formed between the belt pulley (83) and a bearing housing (81).

5. Adjustment drive according to one of the preceding claims, characterized in that the bearing arrangement (97, 88, 9) comprises a rolling bearing, the bearing ring (9) being designed as a race of the rolling bearing.

6. Adjustment drive according to one of the preceding claims, characterized in that the belt wheel (83) has a hub body (85) to which at least one bearing ring (9) is connected.

7. Adjustment drive according to one of the preceding claims, characterized in that the hub body (85) comprises a plastic material and / or a metal.

8. Adjustment drive according to one of the preceding claims, characterized in that the bearing ring (9) comprises a sheet metal part.

9. Adjustment drive according to one of the preceding claims, characterized in that a sensor device (93, 94) is provided for detecting the rotation of the pulley (83).

10. Motor-adjustable steering column (1) for a motor vehicle, having a support unit (2), which can be attached to a vehicle body, and by which an adjusting unit (3) is held, in which a steering spindle (32) is mounted rotatably about a longitudinal axis (L), and having an adjustment drive (5, 6), which is connected to the support unit (2) and to the adjusting unit (3), and by which the adjusting unit (3) can be adjusted relative to the support unit (2), characterized in in that the adjustment drive (5, 6) is designed in accordance with at least one of claims 1 to 9.