STEERING COLUMN FOR A MOTOR VEHICLE

Description

State of the art

[0001] The invention relates to a steering column for a motor vehicle, comprising an outer casing unit which can be connected directly or indirectly to the body of a motor vehicle and in which a casing tube is mounted so as to be adjustable in the longitudinal direction, in which a steering spindle is mounted so as to be rotatable about its longitudinal axis lying in the longitudinal direction, and a clamping device which can be brought into a fixing position in which it fixes the casing unit relative to the casing tube, and into a release position in which it releases an adjustment of the casing tube relative to the casing unit at least in the longitudinal direction, wherein the clamping device has an engagement element extending in the longitudinal direction and supported on the casing tube, with an upper side and lateral edge sides lying parallel to the longitudinal axis, and a locking element supported longitudinally on the casing unit,which is movable by the clamping device in the normal direction of the upper side against the engagement element for adjusting the fixing position, wherein complementary form-locking elements formed on the locking element and the engagement element can be brought into engagement with one another to produce a form-locking effect in the longitudinal direction, and wherein an energy absorption device is arranged between the casing tube and the engagement element, wherein lateral form-locking elements are formed on at least one of the edge sides of the engagement element.

[0002] Steering columns in various designs are known in the art for adjusting the steering wheel position to the driver's seating position. The steering wheel, mounted at the rear end of the steering spindle, can be positioned longitudinally in the vehicle interior by adjusting the longitudinal axis of the steering column.

[0003] The length adjustability is achieved by an inner jacket tube, in which the steering spindle is rotatably mounted, being telescopically extendable and retractable in the longitudinal direction relative to an outer jacket unit. This inner jacket tube can be locked, i.e., releasably fixed, in various longitudinal positions by means of a releasable clamping device. The clamping device, also referred to as a fixing or locking device, acts on the jacket unit held on the body. When the clamping device is open—referred to as the release position—it allows the jacket tube to be moved within the jacket unit to adjust the steering wheel position.By actuating the clamping device, a clamping stroke is generated for locking, so that in the closed state - also called the fixing position or locking position - the jacket tube is clamped in the jacket unit and the steering wheel position is fixed under the expected mechanical stresses during normal driving.

[0004] As an effective measure to improve occupant safety in the event of a vehicle collision, the so-called crash scenario in which the driver impacts the steering wheel at high speed, it is known to design the steering column to be longitudinally collapsible even when the clamping device is in the locking position if a high force is exerted on the steering wheel that exceeds a limit that only occurs in a crash. To ensure controlled deceleration of a body impacting the steering wheel, an energy absorption device is coupled between the jacket unit and the steering column tube. These units are secured together by the clamping device during normal operation, but are pushed together relative to each other in the event of a crash.This converts the introduced kinetic energy into plastic deformation of an energy absorption element, for example by tearing open a tear tab or bending or squeezing an elongated deformation element, such as a bending wire or bending strip.

[0005] A generic steering column is described in DE 10 2016 220 531 A1. The tensioning device described therein comprises an engagement element attached to the casing tube, which is designed as a toothed plate extending in the longitudinal direction. The toothed plate has an upper side with a normal direction perpendicular to the longitudinal direction. On the upper side, positive-locking elements projecting in the normal direction are designed in the form of a toothing, with a plurality of teeth extending transversely to the longitudinal direction. A locking element is supported longitudinally on the outer casing unit and is designed as a toothed block, which has a toothing on its front side facing the upper side of the engagement element, which corresponds to the said toothing of the engagement element.To secure the locking element, the clamping stroke of the clamping device moves the locking element in the normal direction toward the top of the engagement element until the front side comes into contact with the top and the positive locking elements on the locking and engagement elements engage with each other to form a positive connection effective in the longitudinal direction. To release the locking element, the clamping device lifts the locking element in the opposite direction from the engagement element in the normal direction, releasing the positive connection of the gears and allowing the casing tube to be moved longitudinally within the casing unit to adjust the steering wheel position.

[0006] In this generic steering column, the engagement element is connected to the inner jacket tube via an energy absorption device, which forms a rigid connection between the outer jacket unit and the inner jacket tube during normal operation. In the event of a crash, however, such a large force is introduced into the engagement element via the locking element that the jacket unit and the jacket tube move longitudinally against each other, and an energy absorption element integrated in the force flow between the engagement element and the jacket tube is plastically deformed, thereby braking the movement in a controlled manner.

[0007] A steering column of the type mentioned above is known from US 2017 / 320513 A1.

[0008] A disadvantage is the complex manufacturing process for inserting the toothing into the top of the engagement element. Machining results in high tool wear and time expenditure. Furthermore, the effective holding force of the form-locking element depends on the profile height of the form-locking elements in the normal direction and the engagement force exerted by the clamping device in the normal direction on the locking element for fixation.

[0009] In view of the problems explained above, it is an object of the present invention to reduce the manufacturing effort in the production of a steering column and to ensure a high level of functional reliability. Description of the invention

[0010] 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.

[0011] In a steering column for a motor vehicle, comprising an outer casing unit which can be connected directly or indirectly to the body of a motor vehicle and in which a casing tube is mounted so as to be adjustable in the longitudinal direction, in which a steering spindle is mounted so as to be rotatable about its longitudinal axis lying in the longitudinal direction, and a clamping device which can be brought into a fixing position in which it fixes the casing unit relative to the casing tube, and into a release position in which it releases an adjustment of the casing tube relative to the casing unit at least in the longitudinal direction, wherein the clamping device has an engagement element extending in the longitudinal direction and supported on the casing tube, having an upper side and lateral edge sides lying parallel to the longitudinal axis, and a locking element supported longitudinally on the casing unit,which is movable by the clamping device in the normal direction of the upper side against the engagement element to adjust the fixing position, wherein complementary form-locking elements formed on the locking element and the engagement element can be brought into engagement with one another to produce a form-locking effect in the longitudinal direction, and wherein an energy absorption device is arranged between the casing tube and the engagement element, wherein lateral form-locking elements are formed on at least one of the edge sides of the engagement element, it is provided according to the invention that the locking element has at least one side arm which, in the fixing position, engages around an edge side and has form-locking elements corresponding to the lateral form-locking elements of the edge side.

[0012] The engagement element according to the invention, as is known per se, has an upper side facing the locking element in the normal direction, and edge sides that delimit the upper side laterally, i.e., transversely to the normal direction. The edge sides can have edge surfaces extending in the normal and longitudinal directions, which are also referred to as side surfaces. According to the invention, form-locking elements protrude laterally from at least one of the side surfaces, transversely to the normal direction.

[0013] The width of the upper side is specified by the dimension transverse to the normal and longitudinal direction between the edge sides. The height of the edge sides corresponds to the dimension transverse to the longitudinal direction, in the normal direction. Preferably, the engagement element can have a flat, approximately rectangular cross-section with a width greater than a height.

[0014] The positive-locking elements can preferably be designed as a toothing with teeth extending transversely to the longitudinal direction, which have tooth flanks extending transversely to the longitudinal direction, at least in sections in the normal direction. The engagement element can preferably be designed as a tooth plate, in which the positive-locking elements have a toothing on at least one of the edge sides. The toothing can be formed from a plurality of teeth, which protrude laterally, at least in sections, transversely to the normal direction, and whose tooth flanks extend over at least part of their height in the normal direction over the edge side.

[0015] The form-locking elements can be introduced into the edge sides efficiently and cost-effectively, for example by punching, in which a punching tool having the contour of the form-locking elements is moved relative to the engagement element in a machining stroke with a movement component in the normal direction. A strip-shaped engagement element with a flat cross-section can thus be manufactured as a stamped part including the form-locking elements on the edge sides, which reduces manufacturing effort and tool wear compared to inserting form-locking elements into the upper side. Furthermore, the solution according to the invention offers the advantage that skipping of the form-locking elements, i.e. an unintentional displacement of the engagement element and the locking element relative to one another in the fixing position, is effectively prevented in the event of a sudden force introduction, such as in the event of a crash.

[0016] It is particularly advantageous for form-locking elements to be formed on both edge sides and to protrude transversely to the longitudinal and normal directions on both sides of the engagement element. It can be provided that the form-locking elements on the two edge sides are designed symmetrically to one another. Alternatively, it is also conceivable and possible for the form-locking elements on the two edge sides to be designed asymmetrically to one another.

[0017] According to the invention, the locking element has at least one side arm which, in the fixing position, engages around an edge side and has form-locking elements corresponding to the lateral form-locking elements of the edge side. The side arm projects from the locking element in the engagement direction, i.e. in the normal direction towards the upper side, and has an inner side opposite the edge side in the fixing position. The inner side preferably extends parallel to the edge side. On the inner side there are complementary form-locking elements which correspond to the lateral form-locking elements on the engagement element. For example, the locking element is designed as a tartar, in which teeth are formed on the inner side, the tooth flanks of which run parallel to the tooth flanks of the lateral toothing on the engagement element in the normal direction.During fixation, the corresponding lateral positive locking elements of the locking and engagement elements are moved relative to each other, with the tooth flanks that create the positive locking being moved along their extension in the normal direction. This results in the advantage that the positive locking elements engage with their effective tooth cross-section right at the beginning of the fixation movement, and thus more quickly, than if the teeth were engaged transversely to their extension, as with the known positive locking elements on the top side.

[0018] Preferably, lateral form-locking elements are formed on both edges of the engagement element. For example, the engagement element can be designed as a toothed plate, preferably with a flat rectangular cross-section, with both edges having a toothing, each with a plurality of teeth whose tooth flanks run, at least in sections, parallel to the normal direction of the upper side. Such a double-sided toothing can be efficiently manufactured by stamping.

[0019] The locking element preferably has two opposing side arms, between which the engagement element can be received. The side arms protrude in the normal direction toward the engagement part, whereby the locking element has an inverted U-shaped configuration. Because, in the fixed position, the locking element encompasses the engagement element between the opposing inner sides of the side arms, a positive connection is created between the locking element and the engagement element, which is effective laterally transversely to the longitudinal direction.

[0020] The two side arms have inner sides opposite one another transversely to the longitudinal direction. Formed on at least one of the inner sides are form-locking elements which correspond to the engagement element and can be brought into positive engagement. Preferably, both side arms and both edge sides have form-locking elements. The locking element is preferably designed as a toothed wheel with teeth which correspond to the lateral teeth of the toothed plate. In the locking position, the engagement element at least partially encompasses the edge sides of the engagement element with its two side arms. The engagement element is received transversely to the longitudinal direction in a form-locking manner between the side arms, and at the same time, the form-locking effect in the longitudinal direction is created by the form-locking lateral form-locking elements on the side arms of the locking element and the edge sides of the engagement element.

[0021] An advantage of the latter design is that the positive connection of the lateral form-locking elements according to the invention is locked force-free in the locking position, i.e., the fixing position. This means that no holding force needs to be exerted by the clamping device in the engagement direction, i.e., the normal direction, in the fixing position to maintain the positive connection. Because the two side arms laterally encompass the engagement element, the positive connections between the edge sides and the side arms are laterally supported and secured transversely to the normal direction. This ensures that the positive connection is maintained even under very high loads caused by force peaks in the event of a crash, even if the clamping device is damaged.

[0022] An advantageous embodiment provides that the lateral form-locking elements are inclined obliquely relative to the normal direction. One or both edge sides can have inclined surfaces, at least in sections, on which the form-locking elements run tilted relative to the normal direction and which, viewed in cross-section, converge towards the top side relative to the normal direction. Such an inclined surface can, for example, be arranged diagonally in an edge region between the top and edge sides, such that it forms an angle of greater than 90° with the top side. In particular, by arranging inclined surfaces with inclined form-locking elements along both edge sides, a cross-section of the engagement element that converges in a wedge shape towards the top side can be realized. The wedge-shaped cross-section facilitates the insertion of the engagement element in the normal direction between the two side arms of a locking element with a U-shaped cross-section during fixing.The inclined surfaces act as insertion chamfers, ensuring that the locking element is automatically centered on the engagement element transversely to the longitudinal direction during fixation. This results in a further advantage: the form-locking elements inclined on the inclined surfaces, for example, gears with teeth that are at least partially inclined to the normal direction, engage evenly and securely on both edges. This is particularly advantageous when both edges have form-locking elements on inclined surfaces, which are preferably inclined mirror-symmetrically to each other.

[0023] Alternatively or additionally, the locking element can also have lateral form-locking elements inclined at an angle relative to the normal direction, which can be formed on inclined surfaces on the inside of one or both side arms. This causes the gap between the side arms, which is open toward the engagement element, to widen in a V-shape toward the engagement element. This also allows for insertion chamfers to be implemented, which facilitate placement during fastening and can ensure mutual centering of the locking and engagement elements.

[0024] It is possible for the locking element or the engagement element to have inclined positive-locking elements, or for both the locking element and the engagement element to have mutually inclined positive-locking elements arranged on corresponding inclined surfaces. For example, complementary teeth can be inclined at substantially the same angle, at least in some sections.

[0025] The inclined arrangement of the form-locking elements also makes it possible to generate a force transmission through the wedge effect, whereby the force acting during engagement between the form-locking elements is greater than the engagement force exerted in the normal direction for fixing by means of the clamping device. This results in a particularly secure form-locking engagement.

[0026] In principle, diagonally running form-locking elements can be introduced as described for the edge side by punching, cold forming or similarly efficient forming processes.

[0027] It is also possible for the form-locking elements to be convex or concave in cross-section, at least in sections. The form-locking elements, for example teeth of a gearing, run transversely to the longitudinal direction and can be arranged in a linear, elongated manner on a substantially flat base surface, according to the invention on an edge side in the normal direction, or arranged at an angle on an inclined surface, or as in the prior art on a flat upper side. However, in a further development of the invention it is also possible for the form-locking elements to be arranged on a base shape which is shaped outwards or inwards in cross-section, preferably curved. For example, the edge side or the edge region between the edge side and upper side can be convex in cross-section, i.e. rounded outwards, preferably arcuate, with the teeth also having a convex profile following the convexly curved base surface.It is also possible to design one side with a grooved, convex shape. Within a convex or concave contour, the form-locking elements can assume different inclinations relative to the normal direction. This allows the specific advantages of differently inclined form-locking elements to be realized in a single design. Furthermore, rounded form-locking elements can compensate for minor misorientations, for example, due to dimensional tolerances or changing operating conditions, making the form-locking engagement less sensitive to tolerances.

[0028] It is possible that the form-locking elements on the locking and engagement elements are both flat, or concave and complementarily convex, or both convex, or concave and flat.

[0029] It is conceivable and possible for the engagement element to have form-locking elements at least partially on the upper side. Preferably, form-locking elements formed according to the invention in at least one of the edge sides, for example, teeth of a toothing, can extend around the edge region between the edge and upper side and continue over at least a partial area of ​​the upper side. For example, it is possible for the form-locking elements to extend over inclined or rounded base surfaces arranged in the edge region.

[0030] Preferably, an area free of form-locking elements can be provided on the upper side of the engagement element, which area amounts to at least 20% of the width of the engagement element.

[0031] It is advantageous for the engagement element to have a deformation element that is operatively connected to an energy absorption element arranged between the engagement element and the casing tube. The energy absorption device is designed and arranged such that, upon a relative movement of the engagement element and the casing tube in the event of a crash when the tensioning device is in the fixing position, an energy absorption element is plastically deformed, absorbing kinetic energy. The engagement element can transfer the kinetic energy into the energy absorption element via the deformation element. In the event of a crash, the deformation element causes a plastic deformation, for example, by bending, separating, crushing, stretching, machining, or the like, of at least one energy absorption element, or combinations thereof.

[0032] At least one deformation element can preferably be formed integrally with the engagement element, particularly preferably integrally. This enables simplified and cost-effective production and assembly.

[0033] An advantageous embodiment of the invention provides that the engagement element has guide means on its underside facing away from the top side and towards the casing tube. The guide means are designed to guide the engagement element relative to the casing tube in the longitudinal direction and, in the event of a crash, bring about a defined, guided movement of the engagement element relative to the casing tube, such that the energy absorption element arranged therebetween is deformed in a defined manner. The engagement element can, for example, be designed as a rider or sliding piece that can slide longitudinally on a rail or projection on the casing tube, or vice versa. The guide means can then simply comprise a longitudinally continuous guide groove or the like on the underside of the engagement element, which faces away from the top side and towards the casing tube, thereby creating a positive-locking guide transverse to the longitudinal direction.

[0034] It can be provided that the energy absorption element has a longitudinally elongated deformation strip fastened to the casing tube, which is movable in the longitudinal direction under plastic deformation relative to a deformation element. The deformation strip can be designed as a longitudinally elongated strip, for example as a stamped sheet metal strip, which is fixed to the outside of the casing tube in its end regions. Deformation elements arranged on the engagement element, preferably on the underside, can have deformation means that engage with the deformation strip. The deformation means can, for example, have a passage encompassing the deformation strip, the passage cross-section of which is smaller than the outer cross-section of the deformation strip.If the jacket tube is moved relative to the engagement element in the event of a crash, the deformation strip is forced lengthwise through the passage and is thereby crushed and / or machined, thereby absorbing kinetic energy.

[0035] The deformation strip can be guided in a longitudinal guide groove arranged on the engagement element. This allows the deformation strip to fulfill a dual function as an energy absorption and guiding element.

[0036] As an alternative to the described deformation strip, the energy absorption element can comprise a bending strip or wire that is continuously bent by a deformation element of the engagement part in the event of a crash, or is continuously bent while supported between the deformation element and the casing tube. Other known energy absorption systems can also be implemented, for example, by a deformation element formed as a mandrel on the engagement part, which continuously widens a slot of an energy absorption element, or by a detachable tear tab or the like. Description of the drawings

[0037] Advantageous embodiments of the invention are explained in more detail below with reference to the drawings. In detail: Figure 1 shows a steering column according to the invention in a schematic perspective view, Figure 2 shows the steering column according to Figure 1in partially exploded state, Figure 3 a partial view of the steering column according to Figures 1 and 2 in a partially exploded state, Figure 4 shows an engagement element according to the invention and a corresponding locking element in a first embodiment, Figure 5 shows a schematic cross section of the engagement element according to Figure 4 , Figure 6the locking element according to Figure 4 , Figure 7 an engagement element according to the invention and a locking element in a third embodiment, Figure 8 the locking element according to Figure 6 , Figure 9 shows a second embodiment of an energy absorption device in a representation analogous Figure 3 . Embodiments of the invention

[0038] In the various figures, identical parts are always provided with the same reference symbols and are therefore usually named or mentioned only once.

[0039] Figures 1 and 2show a perspective view obliquely from the rear—relative to the direction of travel of a motor vehicle not shown here—a steering column 1 having a support unit 2 with fastening means 21 for connection to the body of the motor vehicle (not shown), for example, as shown, fastening openings with different diameters for improved installation in the motor vehicle. Two opposing side walls 22 and 23 extend downward from the support unit 2.

[0040] Between the side walls 22 and 23, an actuating unit 3 is accommodated, which has a steering spindle 31 mounted in an inner casing tube 32 for rotation about its longitudinal axis L. The casing tube 32 is accommodated in an outer casing unit 33 for longitudinal displacement in the direction of the longitudinal axis L, as schematically indicated by a double arrow. At the rear end, relative to the direction of travel, the steering spindle 31 has a fastening section 34 for the rotationally fixed attachment of a steering wheel (not shown).

[0041] The casing tube 32 has a mounting element 321 made of a plastic material, which is firmly connected to the casing tube 32, for example, by means of a screw connection, rivet connection, or ultrasonic welding. This mounting element 321 has a mounting structure with bores so that a steering column switch module (not shown here) can be connected to the mounting element 321 of the steering column 1.

[0042] The casing unit 33 is pivotally mounted on the support unit 2 about a pivot axis 24 located transversely to the longitudinal axis L. This allows the adjusting unit 3 to be moved up and down in the height direction H relative to the support unit 2 between the side cheeks 22 and 23 to adjust the height position of the steering wheel by pivoting it about the pivot axis 24, as indicated by a double arrow.

[0043] A clamping device 4 is designed to clamp the actuating unit 3 selectively in the fixing position relative to the support unit 2 or to enable an adjustment in the direction of the longitudinal axis L and / or in the height direction H in the release position.

[0044] The clamping device 4 has a clamping bolt 41 as an actuating element, which extends transversely to the longitudinal axis L through elongated holes 25 in the opposing side walls 22 and 23. The elongated holes 25 extend in the vertical direction H. At one end of the clamping bolt 41, an actuating lever 42 is mounted in a rotationally fixed manner, while the other end is rotatably but tensile-resistantly mounted on the side wall 23.

[0045] A lifting disc 43 is connected in a rotationally fixed manner to the actuating lever 42 and is designed as a cam disc with cams projecting axially from the outside against the side cheek 22 in the axial direction of the clamping bolt 41, ie the clamping axis S.

[0046] A fixing element 5 is arranged on the clamping bolt 41 between the lifting disc 43 and the outside of the side wall 22. The clamping bolt 51 extends in the direction of the clamping axis S through an opening of the fixing element 5, through which, as shown in Figure 2 visible. The clamping bolt 41 is rotatable relative to the fixing element 5.

[0047] The fixing element 5 has a pressure plate 53 designed as a cam plate. This has a circular disk-shaped basic shape and is arranged coaxially with the opening 52. On its axial end face, which faces the lifting plate 43 in the assembled state, the pressure plate 53 has axially projecting cams. The cams interact with the corresponding cams of the lifting plate 43 attached to the actuating lever 42 to form a known lifting gear. For fixing, the clamping bolt 41 is rotated about its clamping axis S by means of the actuating lever 42 or alternatively by means of a motor drive (not shown). The fixing element 5 is fixedly held against rotation on the side wall 22. As a result, the lifting disc 43 and the pressure disc 53 perform a relative stroke in the axial direction of the clamping bolt 41, so that the pressure disc 53 and thus the fixing element 5 is pressed from the outside against the side cheek 22 transversely to the longitudinal axis L.As a result, the casing unit 33 and thus the actuating unit 3 are clamped or clamped between the side walls 22 and 23.

[0048] Attached to the fixing element 5 is a locking element 6 designed according to the invention, which can preferably be designed as a tartar and will be explained in more detail below. The locking element 6 protrudes from the outside through the elongated hole 25, directed toward the adjusting unit 3, and is supported therein in the longitudinal direction on the casing unit 3.

[0049] The locking element 6 can be moved by the clamping device 4 in the direction of the clamping axis S against an engagement element 7, which is attached to the casing tube 32, to adjust the fixing position. This engagement movement takes place in the direction of the clamping axis S, as shown in Figure 2 indicated by the arrow, opposite to a normal direction N perpendicular to the upper side of the engagement element 7, as will be explained further below.

[0050] An energy absorption device 8 is arranged between the engagement element 7 and the casing tube 32, which has an energy absorption element 81. In the Figures 1, 2 and 3 In the embodiment shown, the energy absorption element 81 is designed as a longitudinally elongated deformation strip, which is permanently attached at its ends to the outside of the casing tube 32 by means of fastening elements 82 such as rivets or the like, as in Figure 3 recognizable.

[0051] In Figure 4 the locking element 5 is shown together with the engagement element 7 in operative engagement in the fixing position, ie in mutual positive engagement. Figure 5 shows the engagement element 7 in a schematic cross-section, with the section plane parallel to the normal direction N. To increase clarity, the hatching has been omitted. Figure 6 shows the locking element 6 individually cut out.

[0052] The engagement element 7 has an upper side 71 which has a surface normal in the normal direction N. The upper side extends flat in the longitudinal direction L and transversely thereto in the transverse direction Q. Two lateral edge sides 72 extend in the longitudinal direction L and in the normal direction N and, in the embodiment shown, are perpendicular to the upper side 71. The edge sides 72 each have a toothing with lateral form-locking elements 73 which are designed as teeth whose tooth flanks run transversely to the longitudinal axis L. According to the invention, these lateral form-locking elements 73 protrude laterally with their tooth cross section transversely to the normal direction N, wherein their tooth flanks run at least partially in the normal direction N at least in the upper partial region of the lateral surfaces 72.

[0053] In the execution according to Figure 4A special feature is that the form-locking elements 73 extend over the edge regions formed between the upper side 71 and the edge sides 72, with the teeth having an arcuate profile. As a result, the form-locking elements 73 are convex, on a basic shape that connects the upper side 71 with the edge sides 72 and has an arcuate cross-section.

[0054] In their course, the tooth flanks are inclined at least in sections against the normal direction N, and run on inclined inclined surfaces D, as in Figures 4 and 5 schematically shown. While the edge sides 72 can be at right angles to the top side 71, as shown, the inclined surfaces can be inclined at an angle α (alpha) greater than 90° and less than 180° to the top side 71: 90° < α (alpha) < 180°.

[0055] The inclined form-locking elements 73 can be produced with less manufacturing effort than in the prior art, for example by means of obliquely positioned punching tools or the like.

[0056] The form-locking elements 73 can extend from both edge sides 72 to the upper side 71, wherein preferably on the upper side 71 there remains an area 74 free of form-locking elements 73, which area preferably amounts to at least 20% of the width of the engagement element 7, measured in the transverse direction Q.

[0057] The locking element 6 has two side arms 61 which are directed against the normal direction N towards the upper side 71. Figure 6shows a view from the top side 71. On their inner sides 62, which face one another transversely to the normal direction N and in the transverse direction Q, there are arranged form-locking elements 63 which are complementary to the form-locking elements 73 on the engagement element 7. In the example shown, teeth extending transversely to the longitudinal axis L are formed on the inner sides 62, which can engage positively with the toothing of the engagement element 7 to produce a form-locking engagement effective in the direction of the longitudinal axis L.

[0058] From the inner sides 62, the form-locking elements 63 are convexly formed as arcuate teeth towards the front ends of the side arms 61. Along their course, they exhibit a variable inclination relative to the normal direction N, from a parallel position to an orientation substantially perpendicular to the normal direction N. In this case, inclined surfaces D are taken up at least in sections, which Figure 6as in the Figures 4 and 5 are shown schematically.

[0059] In the Figure 4 In the engagement or fixing position shown, the form-locking elements 63 engage the edges of the corresponding form-locking elements of the engagement element 7 to form a longitudinally effective form-lock. The engagement element 7 is at least partially received between the side arms 61 in cross-section. As a result, the locking element 6 is also positively fixed to the engagement element 7 transversely to the longitudinal axis L. Due to the convex shape, the arrangement is insensitive to minor misalignments.

[0060] On its underside facing away from the upper side 61, the engagement element 7 has a guide groove 75 extending in the longitudinal direction as a guide means.

[0061] In Figure 7An engagement element 7 is shown, which has, on its two edge sides 61, form-locking elements 73 projecting transversely to the normal direction N, each of which is designed as a straight toothing with straight teeth running parallel to the normal direction N. Accordingly, the matching locking element 6 has, on the inner sides of the side arms 61, form-locking elements 63 directed towards one another in the form of a corresponding toothing, the tooth flanks of which also run parallel to the normal direction N.

[0062] To fix the locking part 6 is removed from the Figure 6In the release or unfastening position shown, the clamping device 4 moves the locking element 63 against the normal direction N toward the upper side 71 until the engagement element 7 is received between the side arms 61, and the positive locking elements 63 and 73 engage with one another to form a positive locking action in the longitudinal direction. The locking element 6 is also held positively on the engagement element 7 transversely to the longitudinal direction.

[0063] In the guide groove 75, the energy absorption element 81 is as in Figures 1 and 2recognizably recorded. In the undeformed state, the engagement element 7 sits with the guide groove 75 on a holding section 811 of the energy absorption element 81, which has a smaller width than the width of the said guide groove 75. The holding section 811 is followed by a deformation section 812, which has a greater width than the inner width of the guide groove 75. Furthermore, the engagement element 7 can have a guide groove constriction 751, which is also designed as a deformation element and deforms the energy absorption element 81 upon a displacement of the engagement element 7 relative to the energy absorption element 81.

[0064] During normal operation, the engagement element 7 is held in a form-fitting manner in the longitudinal direction in the holding region 811 and, in particular, cannot be displaced into the deformation region 812. In the event of a crash, a high crash force acts on the steering wheel-side end of the steering spindle 31, pressing the deformation region 812 into the guide groove 75 in the longitudinal direction, wherein the deformation region 812 is squeezed, i.e., plastically deformed, in the engagement element 7, whereby kinetic energy is absorbed. In the event of a crash, the engagement element 7 is fixed by the engagement of the locking part 6, so that the casing tube 31, together with the energy absorption element 81, is displaced relative to the engagement element 7, and the energy absorption element 81 is deformed by the engagement element 7.

[0065] In the event of a crash, the guide groove 75 therefore acts simultaneously as a guide and deformation element, which is formed integrally with the engagement element 7.

[0066] Figure 9 shows a further embodiment in which a bending strip 83 is used as the energy absorption element. The bending strip 83 has a first end 831 on a first leg pointing in the longitudinal direction, which is connected via a bend of approximately 180° to a second leg, also pointing in the longitudinal direction, which has a bent hook 832 at its end. The first end 831 is supported longitudinally against a U-shaped retaining profile 84, which is fastened to the casing tube 32.

[0067] The engagement element 7 has a driver pin 76 as a guide means, which is guided through a longitudinally extending slot 841 in the holding profile 84 and engages behind the hook 832 of the bending strip 83.

[0068] In the event of a crash, the driver pin 76 slides along the slot, guided along, and carries the hook 832 longitudinally toward the end 831, whereby the bending strip 83 is continuously bent, i.e., the bend passes through the bending strip 83. Through this plastic bending, kinetic crash energy is converted into deformation and absorbed. The driver pin 76 acts both as a guide and deformation element, which can preferably be formed integrally with the engagement element 7. List of reference symbols

[0069] 1Steering column 2Support unit 21Fasteners 22, 23Side cheeks 24Pivot axis 25Elongated hole 3Adjusting unit 31Steering spindle 32Steering tube 33Steering unit 34Fastening section 4Clamping device 41Clamping bolt 42Actuating lever 43Lifting disc 5Fixing element 53Thrust washer 6Locking element 61Side arm 62Inside 63Form-locking elements 7Engaging element 71Top side 72Edge side 73Form-locking elements 74Free area 75Guide groove 76Drive pin 8Energy absorption device 81Energy absorption element 82Fastening elements 83Bending strip 831End 832Hook 84Retaining profile 841Slot LLongitudinal axis HHeight direction SSclamping axis NNormal direction QTransverse direction

Claims

1. A steering column (1) for a motor vehicle, comprising an outer casing unit (33) which can be connected directly or indirectly to the body of a motor vehicle and in which there is retained so as to be able to be displaced in the longitudinal direction a casing pipe (32), in which a steering spindle (31) is rotatably supported about the longitudinal axis (L) thereof located in the longitudinal direction, and a clamping device (4) which can be moved into a fixing position, in which it secures the casing unit (33) relative to the casing pipe (32), and a release position, in which it releases a displacement of the casing pipe (32) relative to the casing unit (33) at least in the longitudinal direction, wherein the clamping device (4) has an engagement element (7) which is supported on the casing pipe (32) and which extends in the longitudinal direction and which has an upper side (71) which is located parallel with the longitudinal axis (L) and lateral edge sides (72) and a locking element (6) which is supported in the longitudinal direction on the casing unit (33) and which can be moved by the clamping device (4) in order to adjust the fixing position in the normal direction (N) of the upper side (71) against the engagement element (7), wherein complementary positive-locking elements (63, 73) which are constructed on the locking element (6) and the engagement element (7) can be brought into engagement with each other in order to produce a positive-locking connection which is effective in the longitudinal direction and wherein an energy absorption device (8) is arranged between the casing pipe (32) and the engagement element (7), wherein lateral positive-locking elements (73) are constructed at least on one of the edge sides (72) of the engagement element (7), characterized in that the locking element (6) has at least one side arm (61) which engages around an edge side (72) in the fixing position and which has positive-locking elements (63) which correspond to the lateral positive-locking elements (73) of the edge side (72).

2. The steering column as claimed in claim 1, characterized in that the locking element (6) has two mutually opposing side arms (61) between which the engagement element (7) can be received.

3. The steering column as claimed in one of the preceding claims, characterized in that the lateral positive-locking elements (72, 62) are inclined obliquely with respect to the normal direction (N).

4. The steering column as claimed in one of the preceding claims, characterized in that the positive-locking elements (72, 62) are at least partially constructed in a convex or concave manner.

5. The steering column as claimed in one of the preceding claims, characterized in that the engagement element (7) has positive-locking elements (73) at least partially on the upper side (71).

6. The steering column as claimed in claim 5, characterized in that the positive-locking elements (73) are constructed to extend at least partially from the upper side (71) to at least one of the edge sides (72).

7. The steering column as claimed in one of the preceding claims, characterized in that the engagement element (7) has a deformation element (75, 76) which is operationally connected to an energy absorption element (8) which is arranged between the engagement element (7) and the casing pipe (32).

8. The steering column as claimed in one of the preceding claims, characterized in that the engagement element (7) has guiding means (75, 76).

9. The steering column as claimed in one of the preceding claims 7 to 8, characterized in that the energy absorption element (7) has a deformation strip (81) which is elongate in the longitudinal direction and which is secured to the casing pipe (32) and which can be moved in the longitudinal direction with plastic deformation along a deformation element (75).

10. The steering column as claimed in one of the preceding claims, characterized in that the positive-locking elements (63, 73) are constructed as a tooth arrangement with teeth (63, 73) which extend transversely relative to the longitudinal direction.