ADJUSTMENT DRIVE FOR A STEERING COLUMN, DRIVE UNIT FOR AN ADJUSTMENT DRIVE, MOTOR-ADJUSTABLE STEERING COLUMN FOR A MOTOR VEHICLE, AND METHOD FOR PRODUCING AN ADJUSTMENT DRIVE FOR A STEERING COLUMN

Abstract

An adjustment drive for a motor-adjustable steering column for a motor vehicle includes a drive unit having a transmission in which there is mounted a drive wheel. The drive wheel can be driven to rotate about a drive axis and is in operative engagement with a transmission wheel which is mounted in the transmission so as to be rotatable about a transmission axis. The transmission has a drive module, which includes the drive wheel, and a transmission module, which includes the transmission wheel. The drive module and the transmission are connected to one another by a joining connection.

Claims

1.-13. (canceled)

14. An adjustment drive for a motor-adjustable steering column for a motor vehicle, comprising: a drive unit having a transmission; a drive wheel mounted in the transmission and which when driven rotates about a drive axis; and a transmission wheel in operative engagement with the drive wheel, the transmission wheel rotatably mounted in the transmission about a transmission axis, wherein the transmission is composed of a drive module, which comprises the drive wheel, and a transmission module, which comprises the transmission wheel, wherein the drive module and the transmission module are connected to one another by a joining connection.

15. The adjustment drive of claim 14, wherein the drive module comprises a drive part housing in which the drive wheel is mounted, the transmission module comprises a transmission part housing in which the transmission wheel is mounted, and wherein the drive part housing is connected to the transmission part housing via the joining connection.

16. The adjustment drive of claim 15, wherein the drive part housing comprises, in a region of the drive wheel, and the transmission part housing comprises, in a region of the transmission wheel, an open engagement region, wherein the drive wheel and the transmission wheel are in operative engagement with one another through the engagement region.

17. The adjustment drive of claim 14, wherein the drive module and the transmission module comprise corresponding joining elements.

18. The adjustment drive of claim 14, wherein the joining connection comprises a form-fitting and/or force-fitting and/or integrally bonded connection.

19. The adjustment drive of claim 14, wherein the transmission part housing comprises at least one tubular portion which is coaxial to the transmission axis and which is encompassed by the drive part housing at least over a circumferential subregion.

20. The adjustment drive of claim 14, wherein the drive wheel is coupled coaxially to the motor shaft of an actuating motor, and the transmission wheel is connected to a threaded spindle or a spindle nut.

21. The adjustment drive of claim 20, wherein the actuating motor is attached to the drive part housing.

22. The adjustment drive of claim 14, wherein the drive axis and the transmission axis are perpendicular to one another and have a distance from one another which is determined by the axis distance between drive wheel and transmission wheel in operative engagement.

23. The adjustment drive of claim 14, wherein the drive wheel is a worm and the transmission wheel is a worm wheel.

24. A drive unit for an adjustment drive, comprising: a transmission in which there is mounted a drive wheel which when driven rotates about a drive axis and a transmission wheel in operative engagement with the drive wheel; the transmission wheel rotatably mounted in the transmission about a transmission axis, wherein the transmission is composed of a drive module, which comprises the drive wheel, and of a transmission module, which comprises the transmission wheel, wherein the drive module and the transmission module are connected to one another by a joining connection.

25. A motor-adjustable steering column for a motor vehicle, comprising: a carrying unit which is configured to attach to a vehicle body; an actuating unit held by the carrying unit; a steering spindle rotatably mounted in the actuating unit about a longitudinal axis; and an adjustment drive which is connected to the carrying unit and to the actuating unit and by which the actuating unit is adjustable relative to the carrying unit; wherein the adjustment drive comprises: a threaded spindle that engages in a spindle nut; and a drive unit having a transmission in which there is mounted a drive wheel which when driven rotates about a drive axis and which is in operative engagement with a transmission wheel which is rotatably mounted in the transmission about a transmission axis and is connected to the threaded spindle or the spindle nut; wherein the transmission is composed of a drive module, which comprises the drive wheel, and of a transmission module, which comprises the transmission wheel, wherein the drive module and the transmission module are connected to one another by a joining connection.

26. A method for producing an adjustment drive for a motor-adjustable steering column for a motor vehicle, comprising: providing a drive module which comprises a drive part housing having a drive wheel which is rotatably mounted therein about a drive axis; providing a transmission module which comprises a transmission part housing having a transmission wheel which is rotatably mounted about a transmission axis; positioning the drive module and transmission module relative to one another in an engagement position such that the drive wheel and transmission wheel are brought into operative engagement; and fixing the drive module and transmission module in the engagement position.

27. The method of claim 26, wherein a joining connection between the drive part housing and the transmission part housing is produced in order to fix the drive module and transmission module.

Description

DESCRIPTION OF THE DRAWINGS

[0040] Advantageous embodiments of the invention will be explained in more detail below with reference to the drawings, in which specifically:

[0041] FIG. 1 shows a schematic perspective view of a steering column according to the invention,

[0042] FIG. 2 shows a further perspective view of the steering column according to the invention as shown in FIG. 1 from another angle of view,

[0043] FIG. 3 shows a drive unit of an adjustment drive of the steering column as shown in FIGS. 1 and 2,

[0044] FIG. 4 shows the drive unit as shown in FIG. 3 in an exploded state,

[0045] FIG. 5 shows a cross section through a drive unit as shown in FIG. 2 in a first embodiment,

[0046] FIG. 6 shows a cross section through a drive unit as shown in FIG. 2 in a second embodiment,

[0047] FIG. 7 shows a cross section through a drive unit as shown in FIG. 2 in a third embodiment,

[0048] FIG. 8 shows a cross section through a drive unit as shown in FIG. 2 in a fourth embodiment,

[0049] FIG. 9 shows a side view of the drive unit as shown in FIG. 5 in a first variant,

[0050] FIG. 10 shows a side view of the drive unit as shown in FIG. 5 in a second variant.

EMBODIMENTS OF THE INVENTION

[0051] In the various figures, the same parts are always provided with the same reference signs and therefore are generally also only referred to or mentioned once in each case.

[0052] FIG. 1 shows, from obliquely top right, a steering column 1 according to the invention in a schematic perspective view of the rear end with respect to the direction of travel of a vehicle (not shown), where a steering wheel (not shown here) is held in the operating region. FIG. 2 shows the steering column 1 in a view from the opposite side, that is to say as seen from top right.

[0053] The steering column 1 comprises a carrying unit 2 which is designed as a bracket which comprises fastening means 21 in the form of fastening holes for attachment to a vehicle body (not shown). The carrying unit 2 holds an actuating unit 3 which is received in a casing unit 4—also referred to as a guide box or box-section swinging fork.

[0054] The actuating unit 3 comprises a casing tube 31 in which a steering spindle 32 is mounted so as to be rotatable about a longitudinal axis L, said steering spindle extending axially in the longitudinal direction, that is to say in the direction of the longitudinal axis L. At the rear end, a fastening portion 33 to which a steering wheel (not shown) can be attached is formed on the steering spindle 32. At the front end, the steering spindle 32 is connected to a fork of a universal joint 35 in a torque-transmitting manner.

[0055] In order to realize a longitudinal adjustment, the actuating unit 3 is received in the casing unit 4 so as to be telescopically displaceable 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 in the longitudinal direction relative to the carrying unit 2, as indicated by the double arrow parallel to the longitudinal axis L.

[0056] The casing unit 4 is mounted in its front end region in a pivot bearing 22 on the carrying unit 2 so as to be pivotable about a horizontal pivot axis S situated transversely to the longitudinal axis L. In the rear region, the casing unit 4 is connected to the carrying unit 2 via a rotatable actuating lever 41. As a result of a rotational movement of the actuating lever 41 by means of an illustrated actuating drive 6 (see FIG. 2), the casing unit 4 can be pivoted relative to the carrying unit 2 about the pivot axis S which lies horizontally in the installed state, whereby it is possible to carry out an adjustment of a steering wheel attached to the fastening portion 33 in the vertical direction H, which is indicated by the double arrow.

[0057] A first adjustment drive 5 for longitudinally adjusting the actuating unit 3 relative to the casing unit 4 in the direction of the longitudinal axis L comprises a spindle drive having a spindle nut 51 with an internal thread 74 in which a threaded spindle 52 extending along a threaded spindle axis G engages, that is to say is screwed by its external thread into the corresponding internal thread 74 of the spindle nut 51. The threaded spindle axis G of the threaded spindle 52 extends substantially parallel to the longitudinal axis L.

[0058] The spindle nut 51 is mounted in a transmission housing 81 so as to be rotatable about the threaded spindle axis G in a transmission 8, which transmission housing is fixedly connected to the casing unit 4. In the direction of the threaded spindle axis G, which is also referred to below with the same meaning as transmission axis G, the spindle nut 51 is supported axially on the casing unit 4 via the transmission housing 81, as will be explained in more detail below.

[0059] The threaded spindle 52 is connected by way of a fastening element 54 formed on its rear end to the actuating unit 3 via a transmission element 34, specifically fixedly in the direction of the threaded spindle axis G or the longitudinal axis L and fixedly with respect to rotation about the threaded spindle axis G. A so-called plunging spindle drive is realized by the rotationally drivable spindle nut 51 and the threaded spindle 52 which is fixed with respect to rotation.

[0060] The transmission element 34 extends from the actuating unit 3 through a slot-shaped through-opening 42 in the casing unit 4. To adjust the steering column 1 in the longitudinal direction, the transmission element 34 can be moved along freely in the longitudinal direction in the through-opening 42.

[0061] The adjustment drive 5 comprises an electric actuating motor 55 by which the spindle nut 51 can be driven to rotate with respect to the threaded spindle axis G relative to the fixed threaded spindle 52. It is thus possible—depending on the direction of rotation of the actuating motor 55—for the threaded spindle 52 to be displaced in the direction of the axis G translationally relative to the spindle nut 51, with the result that correspondingly the actuating device 3 connected to the threaded spindle 52 is 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.

[0062] In FIG. 2, which shows a perspective view of the steering column 1 from the side situated to the rear in FIG. 1, it can be seen how a second adjustment drive 6 for adjustment in the vertical 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 a threaded spindle axis G. The adjustment drive comprises a transmission 9 in which the threaded spindle 62 is mounted so as to be rotatable in a transmission housing 91, which is fastened to the casing unit 4, about the threaded spindle axis G, which is referred to with the same meaning as a transmission axis G, and is axially supported, in the direction of the threaded spindle axis G, on the casing unit 4. The threaded spindle 62 can be selectively driven to rotate about the threaded spindle axis G in both directions of rotation by an electric actuating motor 65.

[0063] The spindle nut 61 is attached fixedly with respect to a rotation about the threaded spindle axis G on one end of the two-arm actuating lever 41, which is mounted on the carrying unit 22 so as to be rotatable about a pivot bearing 23, and its other arm is connected by the other end to the casing unit 4.

[0064] By rotating the threaded spindle 61 it is possible—depending on the direction of rotation of the actuating motor 65—for the spindle nut 61 to be displaced translationally relative to the threaded spindle 62 in the direction of the threaded spindle axis G, with the result that correspondingly the casing unit 4 connected to the spindle nut 61 via the actuating lever 41, together with the actuating device 3 received in said casing unit, can be adjusted up or down relative to the carrying unit 2 in the vertical direction H, as indicated by the double arrow.

[0065] A so-called rotational spindle drive is realized by the rotationally drivable threaded spindle 62 and the spindle nut 61 which is fixed with respect to rotation.

[0066] The invention relates to the design of a transmission housing 8 or 9, the latter being substantially only distinguished in that, in the transmission housing 9, it is the threaded spindle 52 which is mounted so as to be rotatable about the respective threaded spindle axis G and is mounted fixedly in the axial direction, and, in the transmission housing 8, it is the spindle nut 61. In the following, FIGS. 3 to 9 will be used to explain exemplary embodiments of the transmission housing 9 of the adjustment drive 6 designed as a rotational spindle drive, wherein the features can be transferred to the embodiment of a transmission housing 8 for an adjustment drive 5 designed as a plunging spindle drive by virtue of the fact that, instead of the threaded spindle 62, the spindle nut 51 is arranged in a rotationally drivable manner.

[0067] FIG. 3 shows the drive unit released from the adjustment drive 6 in the assembled state. In FIG. 4, the key functional parts are shown apart from one another in an exploded illustration. The arrangement of the individual parts explained in more detail below can be gathered from the sectional illustrations in FIGS. 5, 6 and 7.

[0068] The transmission housing 91 of the transmission 9 is assembled according to the invention from a drive module 92 and a transmission module 91.

[0069] The drive module 92 comprises a drive part housing 921 in which there is rotatably mounted a drive wheel which is designed as a worm 922 and which is fastened to a driveshaft 923 which extends in the direction of a drive axis A. The worm 922 is preferably fastened to the driveshaft 923 by means of a transverse interference fit. This offers the advantage that there is no need for high pressing-on forces as in the case of a longitudinal interference fit. The worm 922 is preferably inductively heated before the joining operation and then pushed onto the driveshaft 923 with little application of force, with the result that the worm 922 is shrunk on the driveshaft 923 after cooling. The driveshaft 923 can be rotationally driven by the actuating motor 65, with the motor shaft thereof being able to form the driveshaft 923 or being coupled thereto at least in a torque-transmitting manner. The actuating motor 65 is flanged onto the drive part housing 921 and connected thereto, wherein the driveshaft 923 is rotatably mounted, at its end remote from the motor, in a bearing 924 in the drive part housing 921, and, in its region close to the motor, in a motor bearing 925 which, together with the actuating motor 65, is likewise fixed in the drive part housing 921.

[0070] The transmission module 91 comprises a tubular transmission part housing 911 which is formed in a hollow cylindrical manner coaxially to the transmission axis G and in which a transmission wheel designed as a worm wheel 912 is mounted so as to be rotatable about the transmission axis G. The worm wheel 912 is connected to the threaded spindle 62 in a rotationally fixed manner. As can be seen in FIG. 4, the transmission part housing 911 comprises an engagement opening 913 in the region of the worm wheel 912.

[0071] The drive part housing 921 comprises fastening portions 926 which are arranged on an at least partially hollow cylindrical receiving region 927 and are situated opposite to one another with respect to the transmission axis G. The receiving region 927 has approximately the shape of a channel which extends in the direction of the transmission axis G and which has a semicircular open cross section which is configured for the form-fitting reception of the outwardly cylindrical transmission part housing 911.

[0072] In order to produce a transmission 9, a drive module 92 is made available by virtue of the fact that the worm 922 is inserted into the drive part housing 921, said worm being mounted so as to be rotatable about the drive axis A by way of the driveshaft 923 in the bearing 924 in the drive part housing 921. The driveshaft 923 is coupled to the motor shaft of the actuating motor 65, which is likewise connected to the drive module 92.

[0073] Also provided is a transmission module 91, wherein the worm wheel 912 connected to the threaded spindle 62 is mounted in the transmission part housing 911 so as to be rotatable about the transmission axis G, which is identical to the threaded spindle axis G.

[0074] The drive module 92 and the transmission module 91 are positioned relative to one another in such a way that the transmission part housing 911 is received between the fastening portions 926 of the drive part housing 921. The transmission part housing 911 is now positioned transversely to the transmission axis G relative to the drive part housing 921 until the engagement distance E, also referred to as axis distance E, between the drive axis A and the transmission axis G is set, wherein the worm 922 plunges (protrudes) through the engagement opening 913 and engages in the worm wheel 912, and the optimal engagement position of the worm 922 and worm wheel 912 is produced.

[0075] In the optimal engagement position with axis distance E, the drive module 92 is fixed to the transmission module 91 by producing a joining connection between the drive part housing 921 and the transmission part housing 911.

[0076] In the embodiment shown in FIG. 5, joining connections 93 take the form of caulking connections. In order to produce a caulking connection, a pin-shaped tool 11 is used to plastically form in each case an embossment 931 from outside into the fastening portion 926 by means of a linear movement indicated by the double arrow. The embossment 931 projects inwardly in a form-fitting manner and engages in a form-fitting manner in a corresponding cutout 932 in the outer side of the transmission part housing 911. By virtue of the fact that this transmission part housing 911 is for its part received in a form-fitting manner between the fastening portions 926 in a form-fitting manner in the concave receiving region 927 of the drive part housing 921, it is permanently fixed in a form-fitting manner by the introduction of the embossments 931. As a result, the set axis distance E is likewise fixed. For the embodiment illustrated in FIG. 5, the drive part housing 921 is preferably created from a metallic material.

[0077] FIG. 9 is a side view showing the arrangement of an embossment 931 in a fastening portion 926 of the drive part housing 921. An alternative arrangement of a plurality of embossments 931 is shown in FIG. 10. This has the further advantage that, where appropriate, a tilting of the transmission axis G relative to the drive module 92 that is introduced for tolerance compensation can be set and fixed.

[0078] A further possibility of joining connections 93 is shown in FIG. 6. In the latter, the drive part housing 921 is connected to the transmission part housing 911 by means of screws 933 which are guided through the fastening portions 926. The screws 933 make it possible to form a releasable connection which, for example, allows readjustment of the axis distance E.

[0079] As shown in FIG. 7, the joining connections 93 can be realized by welding seams 934 which can also be configured as spot welds. This integrally bonded nonreleasable connection can be efficiently produced and is precise and reliable. An integrally bonded connection can be produced in a particularly efficient manner by means of a laser welding process.

[0080] In the fourth embodiment shown in FIG. 8, joining connections 93 take the form of ultrasonic welding connections. In order to produce a form-fitting connection, a sonotrode 111 is used to form in each case a formation 935 from outside into the fastening portion 926 by local thermal melting of the drive part housing 921 created from plastic. After solidification of the locally melted plastic, there is a form-fitting connection between the transmission part housing 911 and the drive part housing 921. The formation 935 projects inwardly in a form-fitting manner and engages in a form-fitting manner in a corresponding cutout 932 in the outer side of the transmission part housing 911. By virtue of the fact that this transmission part housing 911 is for its part received in a form-fitting manner between the fastening portions 926 in a form-fitting manner in the concave receiving region 927 of the drive part housing 921, it is permanently fixed in a form-fitting manner by the introduction of the formations 935. As a result, the set axis distance E is likewise fixed.

LIST OF REFERENCE SIGNS

[0081] 1 Steering column [0082] 11 Tool [0083] 111 Sonotrode [0084] 2 Carrying unit [0085] 21 Fastening means [0086] 22, 23 Pivot bearing [0087] 3 Actuating unit [0088] 31 Casing tube [0089] 32 Steering spindle [0090] 33 Fastening portion [0091] 34 Transmission element [0092] 4 Casing unit [0093] 41 Actuating lever [0094] 42 Through-opening [0095] 5, 6 Adjustment drive [0096] 51, 61 Spindle nut [0097] 52, 62 Threaded spindle [0098] 54 Fastening element [0099] 55, 65 Actuating motor [0100] 56, 66 Worm [0101] 7 Transmission wheel [0102] 71 Core element [0103] 72 Toothing (worm toothing) [0104] 73 Connecting portion [0105] 74 Internal thread [0106] 8, 9 Transmission [0107] 81, 91 Transmission housing [0108] 91 Transmission module [0109] 911 Transmission part housing [0110] 912 Worm wheel [0111] 913 Engagement opening [0112] 92 Drive module [0113] 921 Drive part housing [0114] 922 Worm [0115] 923 Driveshaft [0116] 924 Bearing [0117] 925 Bearing [0118] 926 Fastening portions [0119] 927 Receiving region [0120] 93 Joining connection [0121] 931 Embossment [0122] 932 Cutout [0123] 933 Screw [0124] 934 Welding seam [0125] 935 Formation [0126] L Longitudinal axis [0127] H Vertical direction [0128] G Threaded spindle axis (transmission axis) [0129] A Drive axis [0130] E Engagement distance