STEERING COLUMN FOR A MOTOR VEHICLE

Description

State of the art

[0001] The invention relates to a steering column according to the preamble of patent claim 1.

[0002] A steering column for a motor vehicle comprises a steering column housing in which a steering spindle is mounted in a steering spindle bearing unit for rotation about its longitudinal axis. At the rear end of the steering spindle, facing the driver, a steering wheel is mounted for the driver to initiate steering commands. The steering column housing is held by a support unit attached to the vehicle body. By adjusting the steering column housing relative to the support unit, the steering wheel position relative to the vehicle body can be adjusted.

[0003] Longitudinal adjustment, in which the steering wheel can be adjusted backward or forward in the longitudinal direction, i.e., along the longitudinal axis relative to the driver's position, is made possible in a steering column of this type by a telescopically adjustable design of the steering column unit and the steering spindle. Furthermore, the steering column can be collapsed longitudinally in the event of a crash, effectively preventing the steering column from penetrating the interior of the passenger compartment and causing injuries to the occupants.

[0004] The casing unit of a generic steering column has at least three telescopic elements that can be telescoped relative to one another, which are also generally referred to as casing or profile elements. This can, for example, be a triple or multiple telescopic arrangement with at least three or more nested telescopic elements designed as casing tubes. This comprises at least one inner casing tube, also referred to as the inner casing tube or inner casing, which extends coaxially into at least one middle or intermediate casing tube, which in turn extends telescopically into an outer casing tube, also referred to as the outer casing tube or outer casing. By pushing the casing tubes together or extending them longitudinally, the casing unit and thus the steering column can be shortened or lengthened.

[0005] The casing tubes can be guided directly against one another, with only casing elements being present as telescopic elements. Designs of casing units are also known in which one or more intermediate elements are arranged between the casing tubes, which are telescopic with respect to the casing tubes. In this case, a plain or rolling bearing unit can be arranged coaxially between two adjacent casing tubes as the telescopic element. Such a rolling bearing unit, which is described, for example, in DE 10 2017 221 004 A1, comprises a rolling element cage arranged coaxially to the casing tubes, in which rolling elements such as balls or rollers are mounted, which can roll between the casing tubes. This forms a linear rolling bearing arrangement that enables smooth adjustment and low-backlash, rigid support. Alternatively, a linear sliding unit can be provided, which is mounted coaxially between the casing tubes, for example as a sliding sleeve.Such a rolling bearing unit or sliding unit, which can be arranged between outer, inner and / or intermediate casing tubes, is also telescopic relative to at least one casing tube and can thus form a generic telescopic element, namely an intermediately mounted intermediate element.

[0006] To adjust the longitudinal position of a steering column, an adjustment force is typically exerted in the longitudinal direction between the outer and inner telescopic elements, i.e., between the outer and inner casing tubes. In autonomous driving, this force is preferably applied by an electric motor. The telescopic element(s) interposed between the outer and inner telescopic elements, such as intermediate casing tubes, rolling bearing units, sliding units, or the like, are moved along in the longitudinal direction exclusively by friction when the casing tubes are adjusted. This can result in undefined slippage, and, particularly after repeated adjustments, the interposed telescopic elements can move to different axial positions relative to the casing tubes in the same steering column setting.A disadvantage of this uncontrolled movement is that the jacket unit can have different stiffness at the same length setting depending on the relative position of the intermediate telescopic elements. Furthermore, the required adjustment force can fluctuate adversely due to uncontrolled longitudinal stop of intermediate elements.

[0007] A steering column of this type is known from DE 10 2004 014506 A1. However, this allows only limited adjustment.

[0008] In view of the problems explained above, it is an object of the present invention to provide a steering column which has an improved adjustment behavior. Description of the invention

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

[0010] In a steering column for a motor vehicle, comprising a casing unit in which a steering spindle is rotatably mounted about a longitudinal axis extending in the longitudinal direction, wherein the casing unit has at least three telescopically guided telescopic elements that are longitudinally adjustable relative to one another, wherein a positioning device for synchronizing the relative movement has a synchronous rotor that is rotatably mounted about a rotor axis lying transversely to the longitudinal axis and whose outer circumference can roll along at least one telescopic element in the longitudinal direction, the invention provides that the synchronous rotor has at least a first synchronous wheel and a second synchronous wheel that are connected to one another in a rotationally fixed manner, wherein the first synchronous wheel has a first pitch circle diameter and can roll along a first telescopic element, and the second synchronous wheel has a second pitch circle diameter and can roll along a second telescopic element,wherein the first pitch circle diameter is different from the second pitch circle diameter.,

[0011] Thanks to the positioning device according to the invention, a forced positioning of the three telescopic elements can be achieved, and the relative longitudinal movement of the three telescopic elements is synchronized, so that even after several adjustment cycles, the telescopic elements remain in a previously determined position relative to each other, and there is no undefined movement of one telescopic element relative to the other two telescopic elements, as in the prior art. Thanks to the solution according to the invention, the rigidity of the steering column can be increased and the adjustment behavior improved.

[0012] In an advantageous further development, the telescopic elements of the casing unit are guided into one another.

[0013] According to the invention, a synchronous gear arrangement is provided with at least two or more synchronous gears connected to one another in a rotationally fixed manner, each having different pitch circle diameters. For example, two, three, or more synchronous gears can be mounted on a common rotor or synchronous shaft.

[0014] Due to the different diameters of the pitch circles (pitch circle diameters), different rolling distances are covered in the longitudinal direction by at least two synchronous gears when rolling around a certain rolling angle. The rolling distance of a synchronous gear describes the distance in the longitudinal direction by which the rotor axis moves for a given rolling angle in the longitudinal direction relative to the telescopic element on which the synchronous gear in question rolls with its outer circumference. The effective diameter of the outer circumference during rolling is defined as the pitch circle diameter. For a given rolling angle α, the rolling distance I is the product of the pitch circle diameter d as: I = d * α.Consequently, the invention advantageously allows the ratio between different relative adjustment paths of the telescopic elements, which correspond to the relative rolling paths of telescopic elements synchronized with each other by the synchronous rotor, to be simply specified by the ratio of the pitch circle diameters of the synchronous gears. Advantageously, the ratio can be freely selected, for example, to realize a different central relative positioning than a fixed one between coaxially adjacent telescopic elements.

[0015] A further particular advantage of this development is that, using a synchronous rotor, the relative longitudinal movement of three or more telescopic elements can be synchronized easily and with minimal design effort. Each of the synchronous wheels can roll on one telescopic element, or on two telescopic elements, for example, on the outside of an inner telescopic element and the inside of an outer telescopic element. Another telescopic element can have a synchronous carrier or be designed as such, in which the synchronous rotor is rotatably mounted about a synchronous axis, so that the synchronous axis can move linearly together with the telescopic element during adjustment.Thus, a single synchronous rotor according to the invention with two synchronous gears can synchronize five telescopic elements, three synchronous gears can synchronize seven telescopic elements, and generally, with a number of n synchronous gears, a telescopic arrangement with (2*n+1) telescopic elements can be synchronized. This makes it easy to realize controlled, synchronized adjustment of multiple telescopes with additional rolling element or sliding units, requiring only one synchronous rotor, or a small number. This reduces manufacturing and assembly costs, and also advantageously reduces the weight and dimensions of an adjustable steering column.

[0016] It can be arranged for two or more synchronous wheels to each roll on a telescopic element, or for all or just some of the synchronous wheels to each roll on two telescopic elements. In this way, a larger number of telescopic elements can be positively coupled and synchronized with each other with less design and construction effort than with the single synchronous wheel in the prior art.

[0017] An advantageous embodiment is that at least one synchronous wheel is designed as a gear. The gear can, for example, be designed as a spur gear with externally rotating teeth and engage with at least one corresponding rack that extends longitudinally on a telescopic element. A gear can engage with two racks simultaneously, which can, for example, be attached or formed on the outside of an inner telescopic element and on the inside of an outer telescopic element. The intermeshing teeth create a positive engagement so that the gear can roll practically slip-free on the rack, and thus on the corresponding telescopic element. The pitch circle diameter relevant for determining the rolling path can be specified in a conventional manner by the gear diameter, module and tooth geometry, for example an involute toothing.The use of gears has the advantage of enabling a precise, slip-free and resilient forced coupling, so that synchronization occurs with a high level of functional and operational reliability.

[0018] The manufacturing and assembly costs can also be advantageously kept low. For example, a rack can be molded into a telescopic element, for example as a single piece through plastic forming or machining, thus achieving a lightweight and compact design. It is also conceivable and possible to provide a rack separately and subsequently mount it on a telescopic element. For example, the rack can be designed as an injection-molded part, for example from a thermoplastic. This rack can then be connected to the telescopic element, for example by means of a clip connection, in which a locking tongue of the rack engages in a corresponding recess in the telescopic element.

[0019] It is possible for at least one synchronous wheel to be designed as a friction wheel. The outer circumference of a friction wheel can roll frictionally, i.e. non-positively, on a linear roller track on the corresponding telescopic element. The outer diameter of the friction wheel is identical to the pitch circle diameter. To avoid slippage, the friction wheel can be designed to increase friction entirely or partially, at least on its rolling outer circumference. Additionally or alternatively, the telescopic element can be designed to increase friction entirely or partially in the area of ​​the roller track on which the friction wheel can roll with its outer circumference. A friction-increasing design can be achieved, for example, by roughening the surface, such as embossing, knurling or the like, and additionally or alternatively by a friction-increasing coating, for example a rubber coating or the like.Such friction wheels can be provided with little manufacturing and assembly effort, and the corresponding roller tracks can also be easily created by longitudinally extending surfaces, tracks, rails or the like.

[0020] It can be provided that the synchronous rotor is rotatably mounted on a synchronous carrier formed by a telescopic element. A synchronous rotor is rotatably mounted on one of the telescopic elements, and the synchronous gears can roll on two or more other telescopic elements. This positively couples and synchronizes the relative movement of the telescopic element forming the synchronous carrier with the other telescopic elements.

[0021] Alternatively, the synchronous rotor can be rotatably mounted on a synchronous carrier that is arranged to be movable relative to the telescopic elements. The synchronous carrier can, for example, comprise a bearing unit that is freely movable longitudinally relative to the telescopic elements and can preferably be guided in the possible direction of movement. In this design, the positive coupling is achieved exclusively by the rolling of the synchronous wheels on the respective telescopic elements, so that with n synchronous wheels (2*n), telescopic elements can be synchronized with each other if each individual synchronous wheel rolls on two telescopic elements.

[0022] If the synchronous gears interact with the telescopic elements exclusively via their rolling outer circumference, the synchronous carrier can be designed separately from the telescopic elements. In this design, none of the synchronous gears is rotatably mounted on a telescopic element. In other words, the common synchronous axis of the synchronous gears of a synchronous rotor is movable longitudinally relative to the telescopic elements. One advantage of this independent synchronous carrier is that virtually any desired motion ratio of the telescopic elements can be freely specified simply by adjusting the pitch circle diameters of the synchronous gears.

[0023] It can be provided that the synchronizer axis is arranged tangentially between two telescopic elements. The synchronizer wheels can therefore roll on a radial inner or outer side of the telescopic elements. A synchronizer axis can be arranged parallel to a tangent relative to the circumference of a substantially tubular telescopic element. A synchronizer wheel can then roll on one or both coaxially adjacent telescopic elements. The racks or roller tracks corresponding to the synchronizer wheels extend longitudinally parallel to tangential planes. It is also possible for a synchronizer wheel of a synchronous rotor to be arranged so that it can only roll between two coaxially adjacent telescopic elements, i.e. no telescopic element is provided which rotatably supports the synchronous rotor.A further synchronous wheel of the synchronous rotor can extend through radial openings or recesses in the adjacent telescopic element(s) and can be rolled on further telescopic elements located coaxially further outwards or inwards.

[0024] It is also possible for the synchronizer shaft to pass essentially radially through at least three telescopic elements. The synchronizer wheels are preferably arranged such that they can each roll longitudinally on a rack or roller track arranged or formed in a radial passage of a respective telescopic element. The advantage of this arrangement is that it is possible to mount all synchronizer wheels, which interact with a plurality, preferably all, telescopic elements in a rolling manner, together in a rotationally fixed manner on a synchronizer shaft. This allows a simple design with one or a few synchronizer rotors to be realized even in a casing unit with a plurality of telescopic elements.

[0025] The telescopic elements can comprise at least one casing tube, which can be an outer, inner, or intermediate casing tube of a casing unit. A telescopic element can also comprise a rolling bearing unit or sliding unit arranged between two casing tubes. In all designs, a synchronous rotor can be mounted on a casing tube or a rolling bearing or sliding unit arranged therebetween, or can be freely rollable, i.e., not rotatably mounted in a telescopic element, between coaxially adjacent telescopic elements.

[0026] The telescopic elements – casing tubes or intermediate elements arranged coaxially therebetween, such as rolling bearing or sliding units – can preferably be tubular with a round or non-circular profile cross-section. A non-circular profile cross-section can, for example, be triangular, quadrangular, hexagonal, octagonal, or multi-edged. With such a multi-edged profile, a synchronous rotor according to the invention can preferably be arranged in the region of a planar, essentially flat side wall. A rack can also be arranged there or be integrated into the wall of the casing tube. Alternatively, the side wall can have a track for a synchronous wheel. Even when the telescopic elements are designed with a non-circular profile cross-section, they are not intended for torque transmission. In this respect, the telescopic elements differ significantly from the steering spindle, because the steering spindle transmits the steering torque applied by the driver.The telescopic elements therefore do not form a torque-transmitting steering spindle or steering shaft, but rather accommodate or support the steering spindle in a rotatable manner.

[0027] It is expedient for the casing unit to have a steering spindle bearing unit. The steering spindle bearing unit comprises one or more bearings in which the steering spindle is rotatably mounted relative to one or more casing tubes. Such bearings, which may include rolling and plain bearings, are preferably arranged in at least one inner casing tube and / or one outer casing tube.

[0028] The steering spindle is preferably designed to be adjustable in length, for example by means of steering spindle sections that can be telescoped in the longitudinal direction.

[0029] To adjust the steering column, it can be provided that a motorized adjustment drive engages two of the telescopic elements in order to adjust the casing tubes relative to one another at least in the longitudinal direction. The adjustment drive can, for example, engage the coaxially outer casing tube of a casing unit and the coaxially inner inner casing tube in order to pull them apart or push them together for longitudinal adjustment. The relative movement of telescopic elements arranged coaxially between the inner and outer casings can be synchronized by a synchronous rotor according to the invention. It is also conceivable and possible for the adjustment drive to engage any two synchronized and thus positively coupled telescopic elements, whereby all of the synchronously coupled telescopic elements can also be adjusted.

[0030] The adjustment drive can comprise a spindle drive with a spindle nut arranged on a threaded spindle and a drive motor, which can rotate the threaded spindle and the spindle nut relative to each other. Such adjustment drives are known in principle in the prior art and are considered reliable and robust. The spindle nut is fixedly mounted on one telescopic element, such as a casing tube, for example, the inner or outer casing tube, in the direction of the longitudinal axis, and the threaded spindle is mounted on another casing tube, the outer or inner casing tube, which can be telescoped thereto.The electric drive motor drives the spindle nut or the threaded spindle in rotation via a suitable gear, for example a worm or belt gear, whereby the threaded spindle or spindle nut, which is fixed relative to it with respect to rotation, is moved translationally in the direction of the spindle's longitudinal axis and, depending on the relative direction of rotation, the telescopic elements are moved together or apart in the longitudinal direction. Description of the drawings

[0031] Figure 1 shows a steering column according to the invention in a schematic perspective view, Figure 2 shows a longitudinal section through the steering column according to Figure 1 , Figure 3 a cross section AA through the steering column according to Figure 2 , Figure 4 an enlarged section of Figure 3 , Figure 5 a cross section through the steering column in a second embodiment, Figure 6 an enlarged section of Figure 5, Figure 7 shows a cross section through a steering column in a third embodiment, Figure 8 shows a fourth embodiment of a steering column according to the invention in a schematic perspective view, Figure 9 shows an enlarged detailed view of Figure 8 , Figure 10 a partially disassembled schematic perspective view of the steering column according to Figure 8 , Figure 11 a detailed view of a synchronous rotor according to the invention of the steering column according to Figure 8 , Figure 12 a cross section through the steering column according to Figure 8 . Embodiments of the invention

[0032] In the various figures, identical parts are always provided with the same reference symbols and are therefore usually named or mentioned only once.

[0033] Figure 1shows a steering column 1 according to the invention in a view obliquely from the rear with respect to the direction of travel, which steering column has an adjusting unit 2. The adjusting unit 2 comprises a casing unit 3, which has an outer casing tube 31, a middle casing tube or intermediate casing tube 32 and an inner casing tube 33, which are referred to collectively as casing tubes 31, 32, and 33. The outer casing tube 31, the intermediate casing tube 32 and the inner casing tube 33 form telescopic elements within the meaning of the invention. These are arranged coaxially one inside the other and are telescopically displaceable in the longitudinal direction, which corresponds to the direction of a longitudinal axis L, as indicated by the double arrow. The intermediate casing tube 32 forms an intermediate element within the meaning of the invention.

[0034] Coaxially arranged between the casing tubes 31 and 32 is a telescopic bearing unit 34, which can be designed as a rolling bearing unit or a sliding bushing. Coaxially arranged between the casing tubes 32 and 33 is a telescopic bearing unit 35, which can be designed as a rolling bearing unit or a sliding bushing. A bearing unit 34 or 35 designed as a rolling bearing unit can comprise a tubular profile-shaped rolling bearing cage, which - as shown in the sectional view of Figure 3 and Figure 4 visible - is arranged coaxially between the casing tubes 32 and 33 and in which rolling elements that can roll longitudinally on the casing tubes 32 and 33 can be rotatably mounted. Alternatively, a tubular profile-shaped sliding bushing can also be provided without the rolling elements.

[0035] The casing tubes 31, 32, 33 and the bearing units 34, 35 are arranged in a telescopically nested manner and form telescopic elements within the meaning of the invention. In the example shown, the telescopic elements 31, 32, 33, 34, 35 are designed as octagonal tube sections.

[0036] A steering spindle 4 is mounted in the casing unit 3, rotatable about the longitudinal axis L, and has a connecting section 41 at its rear end for attaching a steering wheel (not shown). The steering spindle 4 is mounted in the casing tube 33 in a steering spindle bearing unit 42, which can preferably comprise a rolling bearing. Another steering spindle bearing unit of similar design, not visible here, can preferably be arranged in the outer casing tube 31.

[0037] The casing unit 3 is held in a two-part support unit 5, which has fastening means 51 in the form of openings for attachment to a vehicle body (not shown).

[0038] An adjustment drive 6 has a spindle drive with a spindle nut 61 and a threaded spindle 62 screwed therein, which can be driven in rotation relative to one another by an electric motor 63. The threaded spindle 62 extends parallel to the longitudinal axis L and is connected to the inner casing tube 33, and the spindle nut 61 is supported longitudinally on the outer casing tube 31 via the adjustment drive 6. By a relative rotation by means of the motor 63, the threaded spindle 62 and the spindle nut 61 are moved together or apart depending on the direction of rotation, whereby the inner casing tube 33 is retracted or extended longitudinally into the outer casing tube 31, as indicated by the double arrow. This realizes a longitudinal adjustment by means of which a steering wheel attached to the connecting section 41 can be brought forward into a stowed position in which the inner casing tube 33 and the intermediate casing tube 32 are retracted into the outer casing tube 31, i.e.i.e. are sunk forward, or in an operating position in the operating area in which the casing tubes 31, 32 and 33 are extended apart.

[0039] Alternatively, the spindle nut 61 can be supported on the inner casing tube 33 and the threaded spindle 62 on the outer casing tube 31.

[0040] In Figure 1 an adjustment position of the steering column 1 is shown in an operating position in which the intermediate casing tube 32 and the inner casing tube 33 are at least partially extended out of the outer casing tube 31 in the longitudinal direction rearward relative to the direction of travel of the motor vehicle - to the right in the drawing - so that a steering wheel attached to the connecting section 41 is located in the operating area for inputting steering commands.

[0041] The jacket unit 3 is shown in longitudinal section along the longitudinal axis L in Figure 2This shows the coaxial, telescopic arrangement of the telescopic elements 31, 32, 33, 34, 35, comprising the jacket tubes 31, 32, 33 and the bearing units 34, 35.

[0042] The steering spindle 4 is also designed to be longitudinally adjustable and has an inner shaft 43 that extends telescopically into an outer shaft 44. Due to a non-circular profile, this connection is designed to be torque-locking in a conventional manner.

[0043] A positioning device 7 according to the invention has a synchronous rotor 71 which is mounted in the casing tube 32 (intermediate casing tube) so as to be rotatable about the synchronous axis S, as shown in Figure 4 is recognizable.

[0044] The synchronous rotor 71 has a first synchronous wheel 72, which has a first pitch circle diameter d1, and is rotationally fixedly connected to a second synchronous wheel 73, which in the example has a smaller pitch circle diameter d2.

[0045] The synchronous wheel 72 rolls with its outer circumference on a roller track 310 formed on the inside of the casing tube 31 (outer casing tube) and on a roller track 330 formed on the outside of the casing tube 33 (inner casing tube). The synchronous wheel 73 rolls with its outer circumference on a roller track 340 formed on the inside of the bearing unit 34, for example a rolling bearing cage, and on a roller track 350 formed on the outside of the bearing unit 35.

[0046] The synchronous wheels 72 and 73 can be designed as gears with externally circumferential spur gearing, which engage with the roller tracks 310, 330, 340, 350 designed as corresponding racks. As a result, the synchronous wheels 72, 73 roll slip-free in the longitudinal direction along the telescopic elements 31, 33, 34, 35 during adjustment.

[0047] The synchronous rotor 71 positively couples the telescopic elements 31, 32, 33, 34, 35 with respect to their relative movement in the longitudinal direction, and thus synchronizes them. When the jacket tube 33 is moved relative to the jacket tube 31 by an adjustment path w, for example in Figure 4 is pulled out towards the viewer, or in Figure 2to the right, the synchronizer wheel 72 rolls in between and takes the casing tube 32 with it by half the adjustment path w / 2, so that it is always located centrally between the casing tubes 31 and 33. The synchronizer wheel 73 moves the bearing unit 35 with respect to the casing tube 32 in the direction of the casing tube 33, but by a fraction d2 / d1 of the ratio of the rolling circle diameters less than the casing tube 33. If d2 / d1 is 0.5, for example, the bearing unit is moved half as far and is always located centrally between the casing tubes 33 and 32. Analogously, the bearing unit 34, which is also in engagement with the synchronizer wheel 73, is moved in the opposite direction so that it is always located centrally between the casing tubes 31 and 32.

[0048] In this way, all telescopic elements 31, 32, 33, 34, 35 can be synchronized by means of a single synchronous rotor 71 according to the invention.

[0049] The Figure 5 in the same view as in Figure 3 shown version, which in Figure 6 as in Figure 4 is shown enlarged, is characterized in that the synchronous rotor 71 has a total of four synchronous wheels 72, 73, 74, 75 which are connected to one another in a rotationally fixed manner.

[0050] The synchronous rotor 71 is mounted on the casing tube 32 (intermediate casing tube) so as to be rotatable about the synchronous axis S.

[0051] The synchronous wheel 72 has a pitch circle diameter d1 and rolls only on the casing tube 33 (inner casing tube), on the roller track 330.

[0052] The synchronous wheel 73 has a pitch circle diameter d2 and rolls only on the bearing unit 35 arranged between the casing tubes 32 and 33, for example on a rolling element cage of a rolling element unit, on the roller track 350.

[0053] The synchronous wheel 74 has a pitch circle diameter d3 and rolls only on the casing tube 31 (outer casing tube), on the roller track 310.

[0054] The synchronous wheel 75 has a pitch circle diameter d4 and rolls only on the bearing unit 34 arranged between the casing tubes 32 and 31, for example on a rolling element cage, on the roller track 340.

[0055] Through the ratios of the pitch circle diameters d1:d2:d3:d4, which can all be different as in the example shown, the ratios of the relative movements of the telescopic elements 31, 32, 33, 34, 35 can be predetermined in a forced-coupled manner during adjustment and thus synchronized.

[0056] The synchronous wheels 72, 73, 74, 75 can also be designed as friction wheels, which roll with their outer circumference in a frictionally engaged manner in the longitudinal direction on the telescopic elements 31, 33, 34, 35.

[0057] The synchronous gears 72, 73, 74, and 75 can be non-rotatably coupled on a common through shaft. It is also conceivable and possible to construct all synchronous gears 72, 73, 74, and 75 as a single piece, for example, as an injection-molded plastic part or from a cast metal.

[0058] Figure 7 shows a further training in a sectional view such as Figure 4 or 5 , the synchronous rotor 71 being similar to the described embodiments, for example in Figure 4 or 6, can be designed. In this case, the raceway on which the synchronous rotor 71 rolls with the synchronous wheel 72 on the casing tube 33 (inner casing tube) is designed as a crash element 8. Such a crash element 8 can, for example, comprise a toothed rack which is connected to the casing tube 33 via an energy absorption device, or can itself be designed as part of an energy absorption device. For example, the crash element 8 can comprise an element or material which, in the event of a crash, when a body or object impacting the steering column 1 exerts a high force peak in the longitudinal direction on the casing unit 3, is plastically deformed during a relative longitudinal movement of the synchronous rotor 71 to the telescopic elements 31, 32, 33, 34, 35 and thereby absorbs kinetic crash energy and converts it into deformation and heat.For example, the crash element 8 can have a toothing made of a soft material, which is plastically torn or crushed by jerky, non-synchronized slipping of the synchronous wheel 72 in the event of a crash.

[0059] One or more crash elements 8 can also be arranged or formed on other or additional telescopic elements 31, 32, 33, 34, 35. Known energy absorption elements can also be arranged between the crash element 8 and the telescopic element(s) 31, 32, 33, 34, 35, for example, expansion, bending, crushing, and / or tearing elements, which are plastically deformed during a relative movement in the longitudinal direction, absorbing energy only in the event of a crash.

[0060] Figure 8 shows another possible embodiment of a steering column 1 in a perspective overall view, and Figure 9An enlarged view of an alternative embodiment of a positioning device 7 according to the invention. The same reference numerals are used for equivalent parts.

[0061] An electromotive adjustment drive 60, which can be designed similarly to the adjustment drive 6, is arranged between the casing unit 3 and the support unit 5 and enables a height adjustment of the casing unit 3 in the height direction H.

[0062] The positioning device 7 has a synchronous rotor 71, which is Figure 11 is shown separately. This comprises a total of four synchronous gears 72, 73, 74, 75 that are connected to one another in a rotationally fixed manner and are rotatably mounted about their common synchronous axis S in a synchronous carrier 76.

[0063] The synchronous rotor 71 extends with the synchronous axis S through a radial opening 36 passing through the telescopic elements 31, 32, 33, 34, 35. Roller tracks 310, 330, 340, 350 are arranged on each longitudinal edge of the opening 36, which in this embodiment are designed as toothed racks, the toothings of which are formed in the circumferential direction with respect to the longitudinal axis L into the telescopic elements 31, 32, 33, 34, 35.

[0064] The synchronizer carrier 76 is guided longitudinally in the opening 76, with the synchronizer gears 72, 73, 74, 75 meshing with the roller tracks 310, 330, 340, 350. This creates a forced relative positioning of the telescopic elements 31, 32, 33, 34, 35 in the longitudinal direction, thus achieving synchronization. The synchronizer axis S moves together with the synchronizer carrier 76, which is not rigidly connected to any of the telescopic elements 31, 32, 33, 34, 35, but is coupled to them only via the synchronizer gears 72, 73, 74, 75.

[0065] The radial arrangement of the synchronous rotor 71, which radially penetrates the telescopic elements 31, 32, 33, 34, 35 through the opening 76, is in the cross section of Figure 12 clearly visible.

[0066] Figure 10 shows a partially opened view of the casing unit 3, in which the radial arrangement of the synchronous rotor 71 in the opening 76 is illustrated. It also shows how rolling elements 37 are rotatably arranged in the bearing unit 35, which is designed as a rolling element unit and can roll on the casing tubes 32 and 33 during adjustment.

[0067] In an embodiment not shown, it can be provided to use gears and friction wheels combined with one another as synchronous wheels in a single design. List of reference symbols

[0068] 1Lenksäule 2Stelleinheit 3Manteleinheit 31Außenmantelrohr 32Zwischenmantelrohr 33Innenmantelrohr 34, 35Lagereinheit 36Öffnung 37Wälzkörper 310, 330, 340, 350Rollbahnen 4Lenkspindel 41Anschlussabschnitt 42Lenkspindellagereinheit 43Innenwelle 44Außenwelle 5Trageinheit 51Befestigungsmittel 6, 60Verstellantrieb 61Spindelmutter 62Gewindespindel 63Motor 7Positioniereinrichtung 71Synchronrotor 72, 73, 74, 75Synchronräder 76Synchronträger 8Crashelement LLängsachse HHöhenrichtung SSynchronachse d1, d2, d3, d4Wälzkreisdurchmesser

Claims

1. Steering column (1) for a motor vehicle, comprising a sheath unit (3) in which a steering spindle (4) is mounted rotatably about a longitudinal axis (L) extending in the longitudinal direction, the sheath unit (3) having at least three telescopic elements (31, 32, 33, 34, 35) which are adjustable relative to one another in the longitudinal direction and are guided telescopically wherein a positioning device (7) for synchronizing the relative movement has a synchronous rotor (71) which is mounted rotatably about a rotor axis (S) lying transversely to the longitudinal axis and can be rolled with its outer circumference on at least one telescopic element (31, 32, 33, 34, 35) in the longitudinal direction, characterized in in that the synchronous rotor (71) has at least one first synchronizing wheel (72) and one second synchronizing wheel (73), which are connected to one another in a rotationally fixed manner, the first synchronizing wheel (72) having a first pitch circle diameter (d1) and being able to be rolled on a first telescopic element (33), and the second synchronizing wheel (73) has a second pitch circle diameter (d2) and can be rolled on a second telescopic element (35), wherein the first pitch circle diameter (d1) is different from the second pitch circle diameter (d2).

2. Steering column (1) according to claim 1, characterized in that at least one synchronizing wheel (72, 73, 74, 75) is designed as a toothed wheel.

3. Steering column (1) according to one of the preceding claims, characterized in that at least one synchronizing wheel (72, 73, 74, 75) is designed as a friction wheel.

4. Steering column (1) according to one of the preceding claims, characterized in that the synchronous rotor (71) is rotatably mounted on a synchronous carrier which is formed by a telescopic element (31, 32, 33, 34, 35).

5. Steering column (1) according to one of the preceding claims, characterized in that the synchronous rotor (71) is rotatably mounted on a synchronous carrier (76), which is arranged movably relative to the telescopic elements (31, 32, 33, 34, 35).

6. Steering column (1) according to one of the preceding claims, characterized in that none of the synchronous wheels (72, 73, 74, 75) is rotatably mounted on a telescopic element (31, 32, 33, 34, 35).

7. Steering column (1) according to one of the preceding claims, characterized in that the synchronous axle (S) is arranged tangentially between two telescopic elements (31, 32, 33, 34, 35).

8. Steering column (1) according to one of the preceding claims 1 to 6, characterized in that the synchronous axle (S) passes radially through at least three telescopic elements (31, 32, 33, 34, 35).

9. Steering column (1) according to one of the preceding claims, characterized in that the synchronous rotor (71) extends radially through at least one telescopic element (31, 32, 33, 34, 35).

10. Steering column (1) according to one of the preceding claims, characterized in that a telescopic element (31, 32, 33, 34, 35) comprises a casing tube (31, 32, 33).

11. Steering column (1) according to one of the preceding claims, characterized in that a telescopic element (31, 32, 33, 34, 35) comprises a rolling bearing unit (34, 35) or sliding unit arranged between two casing tubes (31, 32, 33).

12. Steering column (1) according to one of the preceding claims, characterized in that the casing unit (3) has a steering spindle bearing unit (42).

13. Steering column (1) according to one of the preceding claims, characterized in that at least one synchronous wheel (72, 73, 74, 75) can be rolled on two telescopic elements (31, 32, 33, 34, 35).