STEERING COLUMN FOR A MOTOR VEHICLE

Abstract

A steering column for a motor vehicle may include a supporting unit and a displacement unit. The supporting unit may be connectable to a chassis of the motor vehicle, and the displacement unit may be displaceable relative to the supporting unit along a displacement path in a crash event. The steering column may further include an energy absorption element positioned between the supporting unit and the displacement unit. In a crash event, the energy absorption element may absorb energy over the displacement path. In some examples, the energy absorption element includes local laser solidifications that help control an energy absorption level of the energy absorption element.

Claims

1.-10. (canceled)

11. A steering column for a motor vehicle comprising: a supporting unit that is connectable to a chassis of the motor vehicle; a displacement unit that is displaceable relative to the supporting unit along a displacement path in a crash event; and an energy absorption element disposed between the supporting unit and the displacement unit, the energy absorption element comprising a local laser solidification, wherein the energy absorption element is configured to absorb energy over the displacement path in the crash event.

12. The steering column of claim 11 wherein the energy absorption element is at least one of a bending tab, a bending wire, a bending tear tab, a crash bead, or a crash sleeve.

13. The steering column of claim 11 wherein the local laser solidification is linear.

14. The steering column of claim 11 wherein the local laser solidification is polygonal.

15. The steering column of claim 11 wherein the local laser solidification has a zigzag shape or a meandering shape.

16. The steering column of claim 11 wherein the local laser solidification is disposed along an outer contour of the energy absorption element.

17. The steering column of claim 11 wherein the local laser solidification is disposed along an inner contour of the energy absorption element.

18. The steering column of claim 11 wherein the local laser solidification is disposed over a partial surface of the energy absorption element or over a full surface of the energy absorption element.

19. The steering column as claimed in claim 1 wherein the local laser solidification in the energy absorption element is provided in a linear, polygonal, zigzag-shaped, or meandering manner, in a manner lying in an area of the energy absorption element or lying along an outer contour and/or along an inner contour of the energy absorption element, or as a line, as a partial surface, and/or over a full surface.

20. The steering column of claim 11 wherein the local laser solidification comprises a first local laser solidification and a second local laser solidification, wherein the first and second local laser solidifications vary in at least one of width, number of branches, or arrangement.

21. The steering column of claim 11 wherein a configuration of the local laser solidification is based at least in part on a region in which the steering column is to be used.

22. The steering column of claim 11 wherein the supporting unit is configured as a bracket and the displacement unit is configured as a holding slide for holding guide box.

23. The steering column of claim 11 wherein the displacement unit is configured as a steering column adjustment.

24. The steering column of claim 11 wherein the local laser solidification comprises a plurality of local laser solidifications having configurations that vary in at least one of width, number of branches, or arrangement, wherein an energy absorption level of the energy absorption element depends on the configurations of the local laser solidifications.

25. The steering column of claim 11 wherein the local laser solidification is achieved by a variation in width, number and/or arrangement of constituent local laser solidifications in order to select a desired energy absorption level of the energy absorption element.

26. The steering column of claim 11 wherein the energy absorption element has a plurality of local laser solidifications that are selected from two different possible local laser solidifications that vary in width, number, and/or arrangement.

27. The steering column of claim 11 wherein the energy absorption element is selected from at least two energy absorption elements with different local laser solidifications depending on a region of use of the steering column.

28. A method of adapting an energy absorption behavior of a steering column that comprises an energy absorption element to a type of motor vehicle, the method comprising introducing local laser solidifications into the energy absorption element.

29. The method of claim 28 further comprising determining at least one of a geometry, a number, a shape, or a thickness of the local laser solidification based on a desired energy absorption level.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0023] Preferred further embodiments and aspects of the present invention are explained in more detail by the description below of the figures, in which:

[0024] FIG. 1 shows a schematic perspective view of a first exemplary embodiment of a steering column;

[0025] FIG. 2 shows a schematic side view of the steering column from FIG. 1 in an initial position for use during the normal driving mode;

[0026] FIG. 3 shows a schematic side view of the steering column from FIGS. 1 and 2 after a displacement of a displacement unit in relation to a supporting unit following an action of force in the event of a crash;

[0027] FIG. 4 shows an embodiment of an energy absorption element in the form of a bending tear tab with a local laser solidification;

[0028] FIG. 5 shows a further embodiment of an energy absorption element in the form of a bending tear tab with a local laser solidification;

[0029] FIG. 6 shows a further embodiment of an energy absorption element in the form of a bending tear tab with a local laser solidification;

[0030] FIG. 7 shows a further embodiment of an energy absorption element in the form of a bending tear tab with a local laser solidification;

[0031] FIG. 8 shows a further embodiment of an energy absorption element in the form of a bending tear tab with a local laser solidification;

[0032] FIG. 9 shows a schematic perspective view of a further exemplary embodiment of a steering column in the initial state;

[0033] FIG. 10 shows an embodiment of an energy absorption element in the form of a bending tab for the steering column shown in FIG. 9;

[0034] FIG. 11 shows a further embodiment of an energy absorption element in the form of a bending tab for the steering column shown in FIG. 9;

[0035] FIG. 12 shows a further embodiment of an energy absorption element in the form of a bending tab for the steering column shown in FIG. 9;

[0036] FIG. 13 shows a schematic, perspective, partially exploded illustration of a further steering column;

[0037] FIG. 14 shows a schematic side view of the holding box of the steering column from FIG. 13 with an energy absorption element in the form of a crash bead;

[0038] FIG. 15 shows a schematic perspective view of an embodiment of an energy absorption element in the form of a crash sleeve; and

[0039] FIG. 16 shows a schematic perspective view of a further embodiment of an energy absorption element in the form of a crash sleeve.

DETAILED DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS

[0040] Preferred exemplary embodiments are described below with reference to the figures. Identical, similar or identically acting elements in the various figures are denoted here by identical reference signs, and a repeated description of said elements is partially dispensed with in the description below in order to avoid redundancy.

[0041] FIGS. 1 to 3 show a steering column 1 which supports a steering spindle 10, at the driver-side end of which a steering wheel (not shown here) can be mounted, via which the driver can then apply a steering torque to the steering spindle 10. The steering torque is transmitted by the steering spindle 10 via a steering shaft 12 to a steering pinion (not shown) which meshes with a rack (likewise not shown) which then, for its part, transmits the predefined steering angle to the steerable wheels of the motor vehicle via corresponding tie rods. An electric and/or hydraulic power assistance can be provided in order to assist the steering torque entered via the steering spindle 10 or in order to introduce an additional steering angle into the steering system, said steering angle then being added to the steering angle applied by the driver via the steering wheel.

[0042] The steering column 1 comprises a supporting unit 2 with a bracket 20 which is connectable to the chassis of a motor vehicle.

[0043] A displacement unit 3 is held on the supporting unit 2 and is displaceable along a displacement path in relation to the supporting unit 2. The displacement unit 3 comprises a holding slide 30 which holds a guide box 32 in which a steering column tube 14 with the steering spindle 10 mounted rotatably therein is arranged.

[0044] In the event of a crash, the displacement unit 3 is displaceable along a displacement path (indicated schematically by the arrow V) in relation to the supporting unit 2. In order to provide this displaceability, the holding slide 30 is held on the supporting unit 2 via a clamping guide 300, but, in the event of a crash, is correspondingly displaceable after overcoming the static friction provided by the clamping.

[0045] In order to prevent displacement of the displacement unit 3 in relation to the supporting unit 2 during normal operation, but to provide a defined absorption of energy along the entire displacement path V during a displacement, an energy absorption element 4 is provided which is arranged between supporting unit 2 and displacement unit 3. When the displacement unit 3, for example the holding slide 30, is displaced in relation to the supporting unit 2, for example the bracket 20, the energy absorption element 4 tears and/or is deformed and, in the process, absorbs crash energy over the displacement path V. By the driver striking against the steering wheel (not shown here), the crash energy is customarily entered here in such a manner that the displacement unit 3 is displaced in relation to the supporting unit 2.

[0046] FIGS. 2 and 3 show two different positions of the displacement unit 3 relative to the supporting unit 2. FIG. 2 shows the initial position of the steering column 1, in which the holding slide 30 is not displaced in relation to the supporting unit 2. In this initial position of the steering column 1, the normal operation of the motor vehicle takes place.

[0047] By contrast, in FIG. 3, the displacement unit 3 in the form of the holding slide 30 has been displaced along the displacement path V in relation to the supporting unit 2 in such a manner that the steering spindle 10 has receded by the displacement path V in relation to its initial position. The steering column 1, in particular the displacement unit 3, takes up this configuration if the displacement unit 3 has traversed the entire displacement path V and has accordingly arrived at a rear end of the displacement path. At least part of the crash energy entered into the steering column 1 and in particular to the displacement unit 3 via the steering wheel can thus be absorbed in a defined manner by the energy absorption element 4 over the displacement path between the initial position and the displaced position. The energy absorption element 4 is deformed and/or torn here.

[0048] In the exemplary embodiment shown, the energy absorption element 4 is designed as a bending tear tab which both bends and also tears at pre-notched points. Energy is accordingly dissipated by the energy absorption element 4 by the material of the energy absorption element 4 tearing and bending.

[0049] The guide box 32 can both be displaced and inclined in relation to the holding slide 30 in order to be able to carry out a positional adjustment of the driver-side end of the steering spindle 10 in order to adapt the position of the steering wheel mounted on the steering spindle 10 to the respective seat position of the driver of the motor vehicle. In order to achieve this adjustment of the position, a clamping mechanism 100 which is known per se is shown, in which a clamping bolt 104 is actuated via a clamping lever 102. The clamping bolt 104 is clamped in a first position of the clamping lever 102, and the clamping bolt 104 is released in a second position of the clamping lever 102. In the released position of the clamping lever 102, a clamping block 106 arranged on the holding slide 30 can be lifted out of a corresponding clamping toothing 108, which is complementary to said clamping block and is arranged on the guide box 32, in such a manner that the guide box 32 can be displaced longitudinally in relation to the holding slide 30 along the direction defined by the axis of the steering spindle 10.

[0050] When the clamping bolt 104 is open, pivoting of the guide box 32 about the axis defined by a pivot axis 105 can also be carried out, and therefore the steering wheel (not shown here) can be adapted in the interior of the motor vehicle to the seat position of the driver both by means of a longitudinal adjustment and also by means of a height adjustment. If an ideal position has been found for the driver, this position is locked again for the driving mode via the clamping lever 102. Such a positional adjustment for a steering column 1 is basically known.

[0051] The energy absorption element 4 is connected via fastening bolts 24 to the bracket 20 and accordingly to the supporting unit 2. The energy absorption element 4 is furthermore connected via fastening bolts 34 to the holding slide 30 and accordingly to the displacement unit 3. Accordingly, the energy absorption element 4 is fixedly connected both to the displacement unit 3 and to the supporting unit 2 and is arranged therebetween. As long as the energy absorption element 4 is not deformed, it ensures a fixed positional relationship between supporting unit 2 and displacement unit 3. The energy absorption element 4 is correspondingly dimensioned in such a manner that it opposes a displacement of the displacement unit 3 in relation to the supporting unit 2 during normal operation. A deformation of the energy absorption element 4 therefore does not occur, and therefore neither does a displacement of the displacement unit 2 in relation to the supporting unit 3, neither during normal driving of the motor vehicle nor if the driver supports himself on the steering wheel, for example when entering and exiting the vehicle.

[0052] FIGS. 4 to 8 show different configurations of the energy absorption element 4 which can be used with the steering column 1 shown in FIGS. 1 to 3.

[0053] The geometrical basic shape, the material and the material strength are identical in the energy absorption elements 4 shown in FIGS. 4 to 8. In other words, the sheet steel billet, on the basis of which the energy absorption element 4 is bent, is identical in all embodiments and also the punching and bending tools required for the production are identical for all energy absorption elements 4. In other words, the initial energy absorption element 4 is identical for all embodiments.

[0054] The energy absorption element 4 comprises recesses 42 through which the fastening bolts 24 for fastening the energy absorption element 4 to the supporting unit 2 can be guided. Furthermore, recesses 44 are provided through which the fastening bolts 34 for fastening the energy absorption element 4 to the displacement unit 3 and in particular to the holding slide 30 are guided. In a preferred configuration, at least one recess 45 is also provided for the insertion of a locking bolt 35. In the event of a crash, the locking bolt 35 can be pulled, preferably pyrotechnically, out of the recess 45 if the energy absorption level of the energy absorption element 4 is intended to be reduced. This may be desirable, for example, if it has been detected that the driver is wearing his seatbelt. If the driver is not wearing his seatbelt, the locking bolt 35 remains in the recess 45 and a higher energy absorption level is provided.

[0055] In the exemplary embodiment shown, the energy absorption element 4 is designed as a bending tear tab and has notches 40 along which the energy absorption element 4 can tear in the event of a crash. At the same time, a tab 400 formed by the tearing is twisted in the event of a crash. Energy is therefore absorbed both by the bending process of the tab 400 and by the energy absorption element 4 tearing along the notches 40, and therefore energy can be absorbed over the entire displacement path.

[0056] In order now to be able to use the energy absorption element 4 for use with different types of vehicle which impose different requirements on the energy absorption behavior, regions of the energy absorption element 4 are subject to a local laser solidification 5.

[0057] For the local laser solidification, a laser beam introduces solidification tracks into the material of the basic billet of the energy absorption element 4. The solidification tracks are introduced here preferably into the untreated sheet steel billet by the laser. For hardenable steels, use is made for this purpose of the martensitic hardness increase, which is known from welding said materials, in the seam region specifically for the local laser solidification.

[0058] In order to achieve the local laser solidification, use is made of a laser L which is indicated schematically in FIGS. 4 to 8 and which guides a focused laser beam S, indicated schematically in FIGS. 4 to 8, at a defined speed over the surface of the sheet steel billet which has already been bent to a finished state. By means of the concentrated application of heat, local heating is achieved which leads to hardening of the material or to brief melting with subsequent solidification, what is referred to as remelt hardening. By the rapid dissipation of heat into the adjacent cold material, rapid cooling of the heated or melted material can be achieved. This results in a local phase change, for example a martensitic hardness increase, in the material structure of the energy absorption element 4 and therefore in a significant increase in strength. The energy absorption behavior of the energy absorption element 4 can therefore be varied depending on the shape, number, arrangement and width of the local laser solidifications 5.

[0059] The local laser solidifications 5 can be introduced into the energy absorption element 4 at a high process speed by irradiation with the laser beam S. A variation in the energy absorption behavior of the energy absorption element 4 can therefore be achieved rapidly and cost-effectively. In particular, for this adaptation, the geometry, the material and the material strength of the initial energy absorption element 4 do not have to be changed.

[0060] In the event of a crash, complex and rapid deformation operations customarily take place in the energy absorption element 4. By means of the local laser solidifications 5, the deformation resistance of the energy absorption element 4 is varied and can thus contribute to achieving a desired energy absorption level. The behavior of compressive stresses and bending stresses can be varied here.

[0061] The exemplary embodiment shown in FIG. 4 schematically shows the laser L which introduces a local laser solidification 5 in the energy absorption element 4 by action upon the material with laser energy by the laser beam S. In the exemplary embodiment shown in FIG. 4, the local laser solidification 5 is designed in the form of two lines which are arranged parallel to each other, extend in the tab 400 and extend in the direction of the notches 40 and therefore also in the tearing direction.

[0062] The term line or linear is understood here as meaning a region with a finite width and a significantly longer extent in the linear direction than in the width direction. In particular, a mathematical line is not meant by this. The line width is customarily determined by the diameter and the energy of the laser beam S striking on the material of the energy absorption element 4.

[0063] Via the introduction of the local laser solidifications 5 by means of the laser L a corresponding change in the material in the energy absorption element 4 can be caused in such a manner that the energy absorption properties of the energy absorption element 4 are influenced by the local laser solidifications 5.

[0064] FIG. 5 shows a further exemplary embodiment of a further energy absorption element 4 which has the same basic structure as the energy absorption element 4 shown in FIG. 4. However, the local laser solidifications 5 introduced by means of the laser L are introduced in a different configuration or in a different shape into the energy absorption element 4. In the exemplary embodiment shown in FIG. 5, the local laser solidifications 5 are shown in the form of a zigzag line in the tab 400.

[0065] In FIG. 6, local laser solidifications 5 are provided not only in the region of the tab 400 but also in those parts 420 of the energy absorption element 4 that do not form the tab. The local laser solidifications 5 in the parts 420 not forming the tab are designed as rectilinear solidification lines extending parallel to the notches 40. The local laser solidifications 5 provided in the tab 400 are in turn arranged in the form of a zigzag line.

[0066] FIG. 7 shows a further embodiment of an energy absorption element 4 in which a local laser solidification 5 is introduced in the form of a meandering line by the laser L.

[0067] By contrast, FIG. 8 shows an energy absorption element 4 in which local laser solidifications 5 which follow the contours of the notches 40 of the tab 400 are provided. In addition to the adaptation of the energy absorption level, the defined tearing of the bending tear tab in the notches is assisted by the solidification along the contour of the notches 40 since the adjacent regions of the notch have increased strength.

[0068] The local laser solidifications 5 necessary for achieving the respective requirements imposed on the energy absorption behavior of the energy absorption element 4 can be determined either via tests, or can be ascertained by means of numerical calculation methods.

[0069] The effect which can be achieved by introducing the local laser solidifications 5 into the energy absorption element 4 is that the energy absorption behavior of the energy absorption element 4 varies depending on the geometry, number, shape and thickness of the local laser solidifications 5. Accordingly, even in the event of provision of identical initial energy absorption elements 4, which have the same geometry, the same material and the same material strength, a different energy absorption behavior can be achieved by means of a variation in geometry, number, shape and thickness of the local laser solidifications 5. With an initial energy absorption element 4, a multiplicity of energy absorption levels can therefore be achieved, and therefore a multiplicity of different types of motor vehicle, which each have different requirements regarding the energy absorption level, can be equipped with an individual basic form of an energy absorption element 4.

[0070] This results in a flexible and modular construction of the steering column 1 to the effect that an individual type of steering column 1 can be installed in a multiplicity of different motor vehicles using identical parts, and it is merely necessary, by means of a laser L, for local laser solidifications 5 to be introduced into the respective energy absorption elements 4, by means of which laser solidifications the respectively desired energy absorption level for the respective type of vehicle is achieved.

[0071] The introduction of the local laser solidifications 5 can take place at different stations in the production process. In particular, however, it can also take place when the steering column 1 is already completely fitted with the energy absorption element 4. Accordingly, the adaptation of the respective steering column 1 may also take place shortly before installation in the motor vehicle.

[0072] By this means, an improved efficiency and cost structure in the production of the steering column can be achieved.

[0073] FIG. 9 shows a schematic perspective illustration of a further steering column 1 which likewise comprises a supporting unit 2, in relation to which a displacement unit 3, which comprises a steering column tube 14, is arranged displaceably in a guide box 32. The steering column tube 14, in which the steering spindle 10 is rotatably mounted, is displaceable in relation to the guide box 32 and also in relation to the bracket 20 in the event of a crash.

[0074] An energy absorption element 4 is provided between the steering column tube 14 and the guide box 32, wherein said energy absorption element is illustrated in the form of the bending tab 46 which is shown by way of example in different forms in FIGS. 10 to 12. The bending tab 46 has recesses 460 in which latching cams 110 of a clamping mechanism 100 engage. The steering column tube 14 can thus be adjusted longitudinally in relation to the guide box 32 in the direction of the axis of the steering spindle 10 if the latching cam 110 is not in engagement with the recesses 460 of the bending tab 46. If the latching cam 110 engages in the recess 460 of the bending tab 46 of the energy absorption element 4, the steering column 1 can only still be longitudinally adjusted by deformation of the bending tab 46.

[0075] Accordingly, in the event of a crash, a displacement of the displacement unit 3 comprising the steering column tube 14, in relation to the supporting unit 2, comprising the guide box 32, is possible by deformation of the energy absorption element 4 in the form of the bending tab 46.

[0076] FIGS. 10 to 12 each show the same basic geometry of the bending tab 46 with its recesses 460, and different designs of the local laser solidifications 5 are shown, by means of which the energy absorption level of the energy absorption element 4 can be varied. Accordingly, a variation in the energy absorption behavior of the energy absorption element 4 can also be achieved again here with the same initial energy absorption element 4 by means of a corresponding treatment to produce the local laser solidifications 5.

[0077] FIGS. 10 and 11 show examples of respective local laser solidifications 5 in the form of lines extending along the bending tab 46 (FIG. 10) or a single line (FIG. 11). In FIG. 12, the laser L is expanded using an expansion lens K, and therefore the local laser solidification 5 here substantially comprises the entire area of the bending tab 46.

[0078] The principle in the exemplary embodiment shown in FIGS. 9 to 12 is in turn the same as that in the exemplary embodiment shown in FIGS. 1 to 8, namely an energy absorption element 4, which is arranged between a supporting unit 2 and a displacement unit 3, for a large number of different use regions as provided from an initial energy absorption element, and the actual adjustment of the energy absorption level takes place via the introduction of local laser solidifications 5 which are each adapted to the desired intended purpose.

[0079] FIGS. 13 and 14 show yet another exemplary embodiment of a steering column 1, wherein FIG. 13 shows a supporting unit 2, which comprises a guide box 32 and a bracket 20, and wherein the displacement unit 3 is accommodated in the guide box 32 in the form of the steering column tube 14 which, for its part, rotatably supports the steering spindle 10.

[0080] An energy absorption element 4 in the form of a crash bead 48 is provided in the guide box 32, said crash bead being arranged between the displacement unit 3 and the supporting unit 2 in such a manner that, when the displacement unit 3 is displaced in relation to the supporting unit 2, the energy absorption element 4 in the form of the crash bead 48 is deformed.

[0081] As emerges from FIG. 14, the energy absorption element 4 in the form of the crash bead 48 can be provided, by means of a laser L, with local laser solidifications 5 by means of which the energy absorption level of the energy absorption element 4 can be secured and in particular can be varied when the steering column 1 from FIGS. 13 and 14 is intended to be used in different types of motor vehicle.

[0082] The local laser solidifications 5 introduced into the crash bead 48 can correspondingly vary in turn with regard to their shape, their number and their width in such a manner that different energy absorption levels of the crash bead 48 can be provided. The guide box 32 with the crash bead 48, and in particular the crash bead 48 can be correspondingly used as the basic energy absorption element 4 for a multiplicity of different types of motor vehicle.

[0083] FIGS. 15 and 16 show a further energy absorption element 4 which is provided in the form of a steering column tube 14 which is designed as a crash sleeve 49 and is accordingly arranged in turn between a displacement unit and a supporting unit. In the event of a crash, the energy absorption element 4 can be deformed by absorbing energy. Local laser solidifications 5 can be introduced by means of a laser L, wherein, in FIG. 15, a local laser solidification 5 is applied in the form of a line extending in the axial direction of the steering column tube 14, and, instead, FIG. 16 shows a local laser solidification 5 which extends around the steering column tube 14 helically or in circumferential circles spaced equidistantly from one another.

[0084] If applicable, all of the individual features which are illustrated in the individual exemplary embodiments may be combined with one another and/or interchanged for one another without departing from the scope of the invention.

LIST OF REFERENCE SIGNS

[0085] 1 Steering column [0086] 10 Steering spindle [0087] 12 Steering shaft [0088] 14 Steering column tube [0089] 100 Clamping mechanism [0090] 102 Clamping lever [0091] 104 Clamping bolt [0092] 105 Pivot axis [0093] 106 Clamping block [0094] 108 Clamping toothing [0095] 110 Latching cam [0096] 2 Supporting unit [0097] 20 Bracket [0098] 24 Fastening bolt [0099] 3 Displacement unit [0100] 30 Holding slide [0101] 32 Guide box [0102] 34 Fastening bolt [0103] 35 Locking bolt [0104] 300 Clamping guide [0105] 4 Energy absorption element [0106] 40 Notch [0107] 42 Recess [0108] 44 Recess [0109] 45 Recess [0110] 46 Bending tab [0111] 48 Crash bead [0112] 49 Crash sleeve [0113] 400 Tab [0114] 420 Part not forming the tab [0115] 460 Recess [0116] 5 Local laser solidification [0117] L Laser [0118] V Displacement path [0119] S Laser beam [0120] K Expansion lens