阅读说明：本技术 用于机动车辆的转向柱 (Steering column for a motor vehicle ) 是由 布赖恩·贝哈姆 勒内·马尔科·施密特 于 2020-02-19 设计创作，主要内容包括：本发明涉及一种用于机动车辆的转向柱(1),该转向柱(1)具有碰撞装置,该碰撞装置包括具有相互面对的表面(58、78)的至少两个部件(51、7),所述至少两个部件(51、7)借助于剪切元件(8)彼此连接,该剪切元件(8)布置在至少部分地穿过部件(51、7)的开口(9)中,使得如果部件(51、7)相对于彼此移动,则剪切元件(8)断成两部分。根据本发明,开口(9)在界定表面(58、78)中的一个表面的至少一个边缘区域中具有加宽部分(91),该加宽部分(91)至少在部分周向的区域上延伸并且朝向相应的另一表面(58、78)敞开以提供改进的预定的断裂连接。(The invention relates to a steering column (1) for a motor vehicle, the steering column (1) having a collision device, the collision device comprising at least two parts (51, 7) having mutually facing surfaces (58, 78), the at least two parts (51, 7) being connected to each other by means of a shearing element (8), the shearing element (8) being arranged in an opening (9) passing at least partially through the parts (51, 7) such that the shearing element (8) is broken into two parts if the parts (51, 7) are moved relative to each other. According to the invention, the opening (9) has a widened portion (91) in at least one edge region of one of the delimiting surfaces (58, 78), which widened portion (91) extends at least over a partial circumferential region and is open toward the respective other surface (58, 78) to provide an improved predetermined breaking connection.)

1. Steering column (1) for a motor vehicle, the steering column (1) having a collision device comprising at least two parts (51, 7) having mutually facing surfaces (58, 78), wherein the at least two parts (51, 7) are connected to each other by means of a shearing element (8), the shearing element (8) being arranged in an opening (9) at least partly through the parts (51, 7) such that the shearing element (8) is broken into two parts if the parts (51, 7) are moved relative to each other,

it is characterized in that the preparation method is characterized in that,

the opening (9) has a widened portion (91) in at least one edge region delimiting one of the surfaces (58, 78), the widened portion (91) extending at least over a partial circumferential region and opening out toward the respective other surface (58, 78).

2. Steering column according to claim 1, characterized in that the surfaces (58, 78) are configured as contact surfaces abutting each other in a shear plane (S), wherein the opening (9) penetrates the two components (51, 7) at least partially transversely to the shear plane (S).

3. Steering column according to claim 1 or 2, characterized in that the opening (9) has a substantially uniform channel cross-section at least in sections, which channel cross-section widens towards the contact surface (58, 78) in the region of the widened portion (91).

4. Steering column according to one of the preceding claims, characterized in that the widened portion has a chamfer (91) and/or a rounding (94) and/or a shoulder (93).

5. Steering column according to claim 4, characterized in that the chamfer (91) encloses a chamfer angle (a) of greater than or equal to 20 ° with the opening axis (B) of the opening.

6. Steering column according to one of the preceding claims, characterized in that the opening is configured as a hole (9) with a circular cross section.

7. Steering column according to one of the preceding claims, characterized in that the shearing element is configured as a shearing rivet (8).

8. Steering column according to one of the preceding claims, characterized in that one of the components (51) is connected to a sheath unit (31) rotatably mounting a steering main shaft (30) and the other component (7) is connected to a support unit (33) supporting the sheath unit (31) and connectable to a body of a motor vehicle.

9. Steering column according to one of the preceding claims, characterized in that the shearing element (8) is constructed of a material having a lower strength than the material of at least one of the parts (51, 7), at least in the region of the shearing plane (S).

10. Steering column according to one of the preceding claims, characterized in that an energy-absorbing element (54, 56) is arranged between the components (51, 7).

11. A method for operating a steering column for a motor vehicle, having a collision device with two parts (51, 7), which parts (51, 7) have mutually facing surfaces (58, 78) and are connected to one another by means of a shearing element (8), which shearing element (8) is arranged in an opening (9) which passes at least partially through the parts (51, 7), wherein the shearing element (8) is sheared and divided into two shearing element fragments (85, 86) when a predetermined collision force (F) acting between the parts (58, 78) is exceeded,

it is characterized in that the preparation method is characterized in that,

at least one of the shear element fragments (85, 86) is plastically formed into a widened portion (91) configured in at least one edge region of a delimiting surface (58, 78) of the opening (9) to form a retaining edge (84), the retaining edge (84) producing a form-fitting connection acting in the passage direction of the opening (9) between the shear element fragment (85, 86) and the component (51, 7).

Prior Art

The invention relates to a steering column for a motor vehicle, having a collision device comprising at least two components having mutually facing surfaces, wherein the at least two components are connected to each other by means of a shearing element which is arranged in an opening at least partially through the components such that the shearing element breaks into two parts if the components are moved relative to each other.

Such steering columns for adapting the steering wheel position to the seating position of the driver of a motor vehicle are known in various embodiments of the prior art. In a universal steering column, a steering wheel attached to the rear end of the steering main shaft can be positioned in the longitudinal direction of the vehicle interior by longitudinal adjustment in the direction of the steering main shaft longitudinal axis.

The longitudinal adjustability is achieved by the inner jacket tube, which is also referred to as the inner jacket tube or simply as jacket tube and in which the steering main shaft is rotatably mounted, being adjustable in a telescopic manner in the direction of the longitudinal axis, i.e. in the longitudinal direction, relative to the outer jacket unit, which is also referred to as the outer jacket unit or simply as jacket unit.

As an effective measure for improving the safety of the occupants in the event of a so-called collision in which the driver strikes the steering wheel at high speed in a vehicle collision, it is known to design the steering column so as to be telescopically extendable in the longitudinal direction and/or telescopically extendable in the vertical direction transversely to the longitudinal direction when a force is exerted on the steering wheel which exceeds a limit value which is present only in the event of a collision, the so-called collision force. As a result, the steering wheel may be deflected in the event of a collision, whereby injury to the occupant may be prevented.

In order to ensure a controlled braking of the body impacting the steering wheel, an energy absorbing device may also be coupled between the two parts of the steering column, which parts move relative to each other when the steering column is telescoped, for example between the outer sheath unit and the inner sheath tube or between the parts connected to the outer sheath unit and the inner sheath tube, respectively, and/or between the adjustment unit supporting the steering main shaft and the support unit for connection to the vehicle body or between the parts connected to the adjustment unit and the support unit, respectively. The energy-absorbing device is capable of converting the introduced kinetic energy into a plastic deformation of one or more energy-absorbing elements, for example by tearing a tear tab or twisting an elongated curved element, i.e. a curved line or a curved strip.

The components that can move relative to one another in the event of a crash are connected together via predetermined breaking elements that absorb the forces acting on the steering wheel in normal operation and prevent the steering column packet from telescoping and responding to an optionally present energy absorption device. Only when a predetermined limit force is exceeded, which occurs in the event of a crash, does the predetermined breaking element break and release the relative movement of the components, so that the steering column can telescope, wherein an optionally inserted energy absorption device can be activated.

In the prior art, two components are known, which abut against one another in a plane parallel to the relative movement in the event of a collision, the so-called shear plane, by means of their surfaces, which are oriented toward one another and are configured as contact surfaces, and which are held together by a shear element, for example in US 2015/0232117 a 1. The shearing element extends through an opening which passes transversely through the component, preferably perpendicularly to the shearing plane, and is fixed in the passage direction of the opening, for example by a shearing element head, for example a rivet head, which is supported on the component from the outside. If the limit force in the event of a collision exceeds the shear strength of the shear element, the shear element is sheared between the shear edges at the edge of the opening relative to the contact surface in the shear plane, i.e. divided into two individual shear element fragments, referred to simply as fragments or chips, and the parts can slide relative to one another in the shear plane. A disadvantage here is that, as a result, loose shear element fragments fall out of the opening in an uncontrolled manner and can move freely in the steering column or passenger compartment of the motor vehicle, and can disturb and impair the function of the steering column and the energy absorption device and can even cause injury to the vehicle driver.

In view of the above problems, it is an object of the present invention to specify an improved predetermined breaking connection with a shearing element and to increase the operational reliability.

Disclosure of Invention

According to the invention, this object is achieved by a steering column for a motor vehicle having the features of claim 1 and by a method according to claim 10. Advantageous developments are disclosed in the dependent claims.

In a steering column for a motor vehicle, which steering column has a crash device comprising at least two parts having mutually facing surfaces, wherein the at least two parts are connected to one another by means of a shearing element which is arranged in an opening which passes at least partially through the parts, such that the shearing element breaks into two parts if the parts are moved relative to one another, it is provided according to the invention that the opening has a widened portion in at least one edge region of the delimiting surface, which widened portion extends at least over a partially circumferential region and opens towards the respective other contact surface.

The through openings extend through the components connected together by means of the shearing element and are formed by individual openings in each component, which openings at least partially overlap, preferably coaxially and/or aligned with each other.

The surfaces may be spaced apart from each other, preferably less than 5mm apart. Alternatively, intermediate elements may be arranged between the surfaces, such as for example membranes, sliding membranes or the like.

Preferably, the surfaces can be configured as contact surfaces which bear against one another in a shearing plane, wherein the opening penetrates the two components at least partially transversely to the shearing plane. The relative movement of the components then takes place as a shearing movement parallel to the shearing plane.

On its opening edge, the opening can have a shearing edge at the transition with at least one surface or contact surface, which shearing edge is configured to shear the shearing element by a relative movement of the components parallel to the surface, preferably by a relative shearing movement parallel to the shearing plane. According to the invention, in the region of at least one shearing edge on one of the parts, preferably on both parts, the opening cross section can be locally enlarged in a widened region of the delimiting surface and/or the contact surface to form a widened portion. For example, the edge region of the opening formed between the inner surface of the opening and the contact surface can be configured with a recess or depression which extends at least partially over the circumference of the opening, so that in the region of the widened portion the opening cross section in the radial direction is enlarged at this point, i.e. transversely to the passage direction of the opening. As a result, in the connected state, a free space is formed between the shearing element and the inner surface of the opening in the region of the widened portion as long as the shearing element is intact. This free space, also referred to as deformation space in the following, surrounds the shearing element at least in some sections in the shearing plane. The deformation space can be provided simply by locally enlarging the opening cross section by treating the contact surface.

In the case of a relative movement of the parts parallel to the surfaces oriented toward one another, the shearing element between the parts is sheared off and broken into two parts and/or thereby separated, i.e. divided into two shearing element fragments.

Preferably, the shearing element substantially fills the open channel cross section, which is the open cross section except for the widened portion, substantially completely, i.e. with little play, in other words at least 95%. In this case, preferably no hollow space in the shearing element itself is taken into account. As a result, in the prior art, the shearing element in the normal connection state in the region of the shearing plane abuts against the shearing edge of the opening which lies on the opening edge. As a result, when the shearing force is exceeded in the event of a collision, the shearing elements are separated cleanly and smoothly even with minimal shearing displacement in the shearing plane, so that the shearing element fragments thus formed can move out of the opening in the direction of the channel against the normal direction of the contact surface and fall out of the component.

However, according to the invention, by means of the widened portion, the spacing between the outer circumference of the shearing element and the inner circumference of the opening transversely to the passage direction can be enlarged in a defined manner in the region of the shearing edge for forming the deformation space. As a result, in the event of a collision, plastic deformation of the shearing element initially occurs in the region of the surfaces and/or the contact surfaces/shearing planes, in which region the material of the shearing element initially flows as a result of the shearing load transversely to the channel direction and is thereby plastically pressed into the deformation space provided by the widened portion and thus at least partially fills this deformation space. The shearing element is sheared off by further relative movement of the parts only after the widened portion has been at least partially filled.

By plastically pressing the shearing element into the deformation space of the widened portion according to the invention, a defined retaining ridge projecting transversely to the passage direction is formed on the shearing element chip during the shearing process. The widened portion is dimensioned such that, in the region of the widened portion, the retaining ridge projects laterally over the opening cross section, except for the widened portion, and thus forms a form-fitting connection element which retains the shear element fragments in the opening in a form-fitting manner in the direction of the passage, opposite to the normal direction of the contact surface. The retaining ridge forms a kind of rivet head, by means of which shear element fragments formed when the shear element is sheared are retained in the opening opposite to the normal direction of the contact surface. As a result, the shear element fragments are fixed on the component between the retaining ridge formed according to the invention and the shear element head supported on the outer surface remote from the contact surface and cannot fall out of the opening in an uncontrolled manner. The normal direction is a direction at right angles to the surface and/or the contact surface and directed away from the surface in the direction of the other surface.

The widened portion according to the invention may be provided in the region of the contact surface of one of the parts or even on two opposite contact surfaces of the two parts. The deformation space available for forming the retaining ridge according to the invention is determined by the free cross-section between the shearing element and the inner surface of the widened portion. The configuration of the widened portions on the surface and/or on both contact surfaces has the following advantages: each of the shear element fragments formed during the shearing process is in each case fixed to the respective component in a form-fitting manner.

Preferably, the opening has, at least in some sections, a substantially uniform channel cross section which widens in the region of the widened portion towards the surface and/or the contact surface. The channel cross-section corresponds to the above-mentioned opening cross-section except for the widened portion, which is preferably substantially filled by the shearing element. To form the widened portion, the channel cross-section can be enlarged simply by the widened portion. In this case, the widened portion extends in the component preferably over a partial region of the length of the opening, which corresponds to the thickness of the component between its contact surface and the outer surface, when measured in the channel direction of the opening transversely to the shearing plane. Thus, if the surface area of the smallest channel cross-section is at most 20% smaller than the surface area of the largest channel cross-section, the channel cross-sections, except for the widened portion, remain substantially the same.

The length of the widened portion in the direction of the passage of the opening is preferably less than 50% of the thickness of the component measured between the surface and/or the contact surface and the outer surface remote from the contact surface and/or the surface. On the contact surface, the outlet cross section of the widened portion, which corresponds to the cross section of the deformation space and thus to the cross section of the retaining ridge, is larger than the minimum passage cross section. Cross-section is preferably understood to mean the cross-sectional surface area.

It may be provided that the widened portion has a chamfer and/or a rounding and/or a shoulder. As a chamfer, the opening edge may be configured to be tapered or rounded with respect to the contact surface. The widened portion of the opening, which opens in a substantially funnel-shaped manner towards the contact surface, can be configured by means of a conical chamfer.

Advantageously, the chamfer encloses a chamfer angle of greater than or equal to 20 °, preferably 30 °, with the opening axis of the opening. The axis extending in the passage direction of the opening is considered as the opening axis, which is preferably parallel to the normal direction of the contact surface. For example, if the opening is configured as a cylindrical bore, the opening axis is the same as the bore axis. As a result, it is ensured that a widened portion sufficient for forming a retaining ridge to produce a reliable form-fitting connection can be realized in a relatively short widened portion. Furthermore, it is possible to ensure reliable plastic forming in the deformation space to form the retaining ridge without premature shearing, which is undesirable.

Alternatively or additionally, the opening edge may have a rounded portion. The rounding can be configured annularly or at least in some sections as a ring-convex surface, i.e. arcuate in cross section. The arcuate rounding has the advantage that plastic deformation occurs gradually along the curved portion when the widened portion is filled, and the notch effect that may occur on sharp edges can be reduced. Preferably, the rounding can have a radius of greater than or equal to 0.5mm, particularly preferably greater than or equal to 1 mm.

Alternatively or additionally, the opening edge may have a shoulder, which may be configured as an at least partially circumferential step. Such a step can be realized, for example, by a widened portion with a stepped bore which is integrated in the contact surface and has a larger diameter, i.e. a widened portion diameter, which is larger than the opening cross section which, in the case of a circular opening, corresponds to the opening and/or the passage diameter.

The opening may be configured as a bore having a circular cross-section. The hole has a hole diameter or an opening diameter which is enlarged in the widened portion towards the contact surface to a larger widened portion diameter relative to the hole diameter or the opening diameter. For example, the bore may widen in a conically funnel-shaped manner by means of a conical chamfer. It is also possible to provide a stepped bore bounded by contact surfaces, wherein a shoulder or step is formed between the larger widened portion diameter and the bore diameter. In adaptation to the bore, the shearing element may also comprise a circular cross-section with a shearing element diameter, such that the shearing element substantially, i.e. substantially fills the bore cross-section with little play.

It is conceivable and possible that, in order to optimize the formation of the retaining ridge and adapt the shearing properties to the two contact surfaces which bear against one another, differently designed widenings may be combined, for example a conical opening edge on one side and a rounded opening edge on the other contact surface.

The widened portion may extend over the entire circumference of the opening or over a partial circumferential region. Preferably, the widened partial circumferential region lies in the shearing direction, i.e. in the direction of the mutual shearing movement of the two components. A local shear geometry is achieved, which allows an optimized introduction of shear forces.

Preferably, the shearing element can be configured as a rivet. The rivet can be configured, for example, as a solid rivet, a hollow rivet or tubular rivet, a semi-hollow rivet, a clinch rivet or the like, wherein the rivet head is plastically formed on a rivet shaft which passes through the opening and out of the two components on both sides, said rivet head in each case being supported in a form-fitting manner on the outer surfaces of the components in the direction of the passage of the opening. Preferably, the rivet has a circular rivet cross-section corresponding to the circular opening cross-section. Since the rivet has a defined solid or hollow cross section at least in the region of the shear plane, which consists of a material having a defined shear strength that is lower than the material strength of at least one of the two parts, the breaking or loosening behavior of the shear connection can be predetermined in a defined manner.

It may be advantageous for one part to be connected to a sheath unit, on which the steering spindle is rotatably mounted, and for the other part to be connected to a bearing unit, which bears the sheath unit and can be connected to the body of the motor vehicle. For example, one component can be connected to a sheathing tube which, in the event of a crash, can telescope relative to the other component in the direction of the longitudinal axis of the steering column about which the steering shaft can rotate, the other component in turn being connected to a sheathing or supporting unit which is supported in the longitudinal direction directly or indirectly on the body of the motor vehicle.

Advantageously, the shearing module is made of the following materials at least in the region of the shearing plane: the material has a lower strength than the material of at least one of the components, preferably a lower strength than the material of the components. If the components are made of, for example, steel, the shearing elements may be made of, for example, aluminum, non-ferrous metals, plastics, etc. If other materials are used for these components, the shear strength of the shearing elements can be adapted thereto in order to ensure that the shearing elements separate reliably in the event of a crash and that no damage is caused to the components during the shearing process.

An advantageous embodiment of the invention provides that an energy-absorbing element is arranged between the components. In this arrangement, the shearing element forms a predetermined breaking element which is arranged parallel to the at least one energy-absorbing element with respect to the force transmission in the direction of the shearing movement in the event of a crash and ensures that in normal operation forces occurring between the two components are absorbed and cannot act on the energy-absorbing element. The shearing element is sheared off and the relative movement of the two parts is released, so that the energy-absorbing element or elements can be deformed to absorb kinetic energy only when a predetermined limit force, which occurs in the event of a collision, is exceeded. The energy absorbing element may be inserted and supported between, for example, the outer sheath unit and the inner sheath tube, so that in the event of a crash, a telescopic expansion of the steering column is possible after the shearing element is sheared off. For example, in the prior art, bending and/or tearing tabs, clamping elements, separating elements or expansion elements are referred to as energy-absorbing elements in many different embodiments, which allow converting kinetic energy into plastic deformation work via a predetermined deformation path. In contrast to the design according to the invention, the deformation path extends in the shearing direction, for example in the longitudinal direction of the telescopically extendable steering column arrangement.

The invention also relates to a method for operating a steering column for a motor vehicle, which steering column has a collision device, the collision device has at least two parts, which have surfaces facing each other and are connected to each other by means of a shearing element, the shearing element is arranged in an opening which passes at least partially through the two parts and has a shearing edge at a transition with at least one surface, wherein the shear element is sheared and separated into two shear element fragments when a predetermined impact force acting between the components is exceeded, wherein, according to the invention, it is proposed that at least one of the shear element fragments is plastically formed into a widened portion configured in at least one edge region of the opening delimiting the contact surface, so as to form a retaining ridge, the retaining ridge produces a form-fitting connection which acts in the direction of the open passage between the shear element fragment and the component.

Preferably, a method is proposed for operating a steering column for a motor vehicle, which steering column has a crash device with two parts which bear against one another in a shear plane against mutually facing contact surfaces and are connected together by means of a shear element which is arranged in an opening which passes through the two parts transversely to the shear plane and has a shear edge at a transition with at least one contact surface, wherein the shear element is sheared and divided into two shear element fragments when a predetermined impact force acting between the parts in the direction of the shear plane is exceeded, wherein it is proposed according to the invention that at least one of the shear element fragments is plastically formed into a widened portion which is configured in at least one edge region of the opening which delimits the contact surface, to form a retaining ridge which produces a form-fitting connection acting in the direction of the open channel between the shear element fragment and the component.

As already mentioned, the opening has a widening on at least one contact surface, preferably on both contact surfaces, which widening extends at least over a partial circumferential region and opens out towards the contact surface. In the method according to the invention, in the event of a collision, a portion of the kinetic energy acting between the components in the shearing direction is first used to plastically press the shearing element in the region of the shearing plane into the deformation space formed in the widened portion according to the invention in the region of the widened portion. As a result, the retaining ridge is plastically deformed on the shearing element and projects laterally over the opening cross section except for the widened portion. After or in some cases during the plastic deformation for forming the retaining ridge, the shearing elements are sheared off on an outer shearing edge arranged on the edge of the widened portion with respect to the contact surface. Due to the deformation in the widened portion according to the invention, one or both of the shearing element fragments has a retaining ridge which ensures a positive fixing to one or more components in the channel direction.

In the event of a crash, the shear element can be plastically deformed by means of the widened portion according to the invention as a result of the crash energy, which allows a reliable fixing of the shear element fragments and thus avoids damage to the energy absorption device. As a result, the safety level can be improved.

Drawings

In the following, advantageous embodiments of the invention are described in more detail with reference to the accompanying drawings. In detail:

figure 1 shows a steering column according to the invention in a perspective view,

figure 2 shows the steering column according to figure 1 in another perspective view,

figure 3 shows a detail of the steering column according to figure 1 in an exploded view,

figure 4 shows a cross section through the steering column according to figures 1 to 3,

figure 5 shows an enlarged detail of figure 4,

figure 6 shows an enlarged schematic view similar to figure 4 of a shear rivet connection in normal operation in a first embodiment according to the invention before it is sheared off,

figure 7 shows a view of the shear rivet connection according to figure 6 after it has been sheared off,

figure 8 shows an enlarged schematic view as in figure 6 before being sheared of a shear rivet connection in normal operation according to a second embodiment of the invention,

figure 9 shows a view of the shear rivet connection according to figure 8 after it has been sheared off,

figure 10 shows an enlarged schematic view as in figure 6 of a shear rivet connection according to the invention in a third embodiment,

figure 11 shows an enlarged schematic view as in figure 6 of a shear rivet connection according to the invention in a fourth embodiment,

figure 12 shows an enlarged schematic view as in figure 6 of a shear rivet connection according to the invention in a fifth embodiment,

figure 13 shows a schematic view of the contact surface as seen in the direction of the channel of the opening in the first embodiment,

fig. 14 shows a schematic view of the contact surface as seen in the channel direction of the opening in the first embodiment.

Detailed Description

In the various figures, identical components are always provided with the same reference numerals and therefore will generally also be referred to and/or referred to only once in each case.

Fig. 1 schematically shows a steering column 1 according to the invention in a perspective view obliquely from behind (with respect to the direction of travel of a motor vehicle, not shown).

The steering column 1 can be fastened to the body of a not shown motor vehicle by means of a bearing unit (bracket) 2. The support unit 2 comprises fastening means 21, for example fastening openings, for attachment to the vehicle body.

The steering main shaft 30 is mounted in a rotatable manner in an inner sheathing tube 31, also referred to as inner sheathing tube or sheathing tube 31, about its longitudinal axis L extending in the longitudinal direction. A fastening section 32 for fastening a steering wheel, not shown, is formed at the rear on the steering spindle 30. The inner sheath tube 31 is held in an outer sheath unit 33, also referred to as outer sheath unit 33 or simply sheath unit 33, displaceable in a telescopic manner in a longitudinal direction, as indicated by the double arrow parallel to the longitudinal axis L.

The motorized adjustment drive 4 comprises an electric drive unit 41 with an electric motor, which electric drive unit 41 is supported in the longitudinal direction on the outer jacket unit 33 by means of a U-shaped bearing part 44, and by means of which electric drive unit 41 a threaded spindle (spindle) 42 extending substantially in the longitudinal direction can be rotatably driven, which threaded spindle is screwed into a spindle nut 43, which spindle nut 43 is fixedly arranged in terms of rotation relative to the threaded spindle and is supported in the longitudinal direction on the inner jacket tube 31 via a bearing element 45. As a result, a so-called rotary spindle drive is realized, in which the spacing between the drive unit 41 and the spindle nut 43 in the longitudinal direction is adjustable by rotatably driving the threaded spindle 42 by means of the drive unit 41. By activating the drive unit 41, the inner sheath tube 31 can be retracted or extended relative to the outer sheath unit 33 for longitudinal adjustment of the steering column 1 in a telescopically telescopic manner, as indicated by the double arrow.

An energy absorbing device 5, which will be described in more detail below, is arranged between the outer sheath unit 33 and the inner sheath tube 31. This energy absorbing device can be identified in fig. 2, in fig. 2 the support unit 2 and the outer sheath unit 33 are omitted in the same perspective view as in fig. 1 for greater clarity. Fig. 3 shows an exploded view of the arrangement of fig. 2, which is exploded transversely to the longitudinal axis L.

The energy absorption device 5 comprises a housing 51 in the form of a C-shaped rail with a substantially rectangular cross section, also referred to as a retaining profile 51, which is fixedly connected to the inner jacket tube 31 and extends in the longitudinal direction, wherein the open cross section is oriented towards the outer face of the inner jacket tube 31. The housing 51 is fixedly connected to the sheathing tube 31, for example by means of laser welding, by means of form-fitting connecting elements 510 engaging in corresponding receiving openings 310 in the inner sheathing tube 31. The housing 51 has on its radially outwardly directed outer face a groove 52 extending parallel to the longitudinal axis L.

In the housing 51, first and second energy-absorbing elements 54, 56 are arranged spaced apart in the longitudinal direction, the first and second energy-absorbing elements 54, 56 being designed in each case as a U-shaped bent wire and/or bent strip with a first limb which is connected to a second limb via a section bent back through approximately 180 °. In each case, a driving hook 544 and/or 564 is configured at the end of the second limb. In each case, the energy-absorbing elements 54 and 56 are supported by their first limb against abutments 546 and/or 566 counter to the longitudinal direction, these abutments 546 and/or 566 projecting inwards into the cross section of the housing 51 and forming in each case a stop in the longitudinal direction.

The energy absorbing elements 54 and 56 may be configured as stamped components so that cost-effective production is ensured.

The housing 51 forms in the context of the present invention a first component which is fixedly connected to the inner jacket tube 31. The housing 51 has an outer contact surface 58 parallel to the longitudinal axis L with respect to the inner jacket tube 31, which outer contact surface 58 faces the viewer in fig. 3.

The carrier plate 7 has a contact surface 78, which contact surface 78 is parallel to the contact surface 58 and in the mounted state lies flat against the contact surface 58 of the housing 51 in the shearing plane S, as described in more detail below.

The spindle nut 43 is connected to the carrier plate 7 via a bearing element 45 and is supported in the longitudinal direction.

First coupling element 60 is fixedly supported in the longitudinal direction on carrier plate 7 and extends through slot 52 and is connected to drive hook 564 of energy-absorbing element 56.

The second coupling element 61 may be coupled to the driving hook 544 of the energy absorbing element 54 through the slot 52 by means of a thermo-electric actuator 62 fixedly connected to the carrier plate 7.

The shear rivet 8 forming the shear element according to the invention is guided through an opening 9, which opening 9 passes through the carrier plate 7 and the housing 51 transversely to the longitudinal axis L and which opening 9 is configured in the example as a hole with a circular channel cross section and with a hole axis B. In normal operation, the carrier plate 7 is connected to the housing 51 by means of shear rivets 8, wherein the contact surfaces 58 and 78 abut against each other in a shear plane S, as can be recognized in the cross-sectional views of fig. 4, 5, 6, 8, 10, 11 and 12.

Fig. 5 shows an enlarged portion of the entire cross-section of fig. 4. In fig. 6 to 12, the elements essential to the invention, namely the shear rivet 8, the carrier plate 7 and the housing 51, are only schematically illustrated.

The shear rivet 8 has a rivet shaft 81, also referred to simply as a shaft, which rivet shaft 81 extends through the opening 9, and which rivet shaft 81 has a cylindrical rivet cross section which substantially fills the opening cross section, so that there is only a small play between the rivet shaft 81 and the inner surface of the opening 9, which play is only a small fraction of the rivet shaft diameter and/or the opening diameter.

By means of a first rivet head 82, the shear rivet 8 is supported outwardly against the outer surface 59 of the housing 51 remote from the contact surface 58, and by means of a second rivet head 83, the shear rivet is supported from the outside against the outer surface 79 of the carrier plate 7 remote from the contact surface 78. The contact surface 58 of the housing 51 and the contact surface 78 of the carrier plate 7 are supported relative to one another in the shear plane by means of the shear rivet 8.

The shear rivet 8 may be designed as a hollow rivet or a semi-hollow rivet as shown in fig. 6 to 11, or even as a solid rivet as shown in fig. 12.

In the embodiment shown in fig. 6, the opening 9 in the housing 51 has a circumferential chamfer in at least one edge region delimiting the contact surface 58, in order to form a conically funnel-shaped widening 91 which opens towards the contact surface. The chamfer encloses a chamfer angle a (alpha) with the bore axis B of preferably greater than or equal to 20 °, preferably 30 °. An annular free deformation space 92 is defined between the cylindrical outer face of the rivet shaft 81 and the conical inner face of the widened portion 91.

The carrier plate 7 is supported via the adjusting drive 4 and the outer jacket unit 33 by means of the support unit 2 on the body of the motor vehicle and the housing 51 on the inner jacket tube 31. In the event of a collision, a high force peak, the so-called collision force F, which acts as a shearing force F parallel to the shearing plane S between the housing 51 and the carrier plate 7 as shown in fig. 7, is transmitted in a pulsed manner via the steering spindle 30 to the inner jacket tube 31. In the event of a crash, the inner jacket tube 31 is displaced together with the housing 51 relative to the carrier plate 7. As a result, the shearing element 8 is subjected to a shearing force and thereby deformed in the region of the widened portion 9. In fact, the material of the shearing element 8 flows into the free deformation space 92 substantially in the direction of the shearing plane S — flows upwards in the view of fig. 7 into the free deformation space 92 — and forms a plastically formed retaining ridge 84 in the free deformation space, which retaining ridge 84 fills the deformation space 92 at least partially transversely to the hole axis B provided by the widened portion.

By means of a further relative movement, the shearing module 8 is sheared in the shearing plane S and is divided into two individual shearing rivet fragments 85, 86, referred to simply as fragments 85, 86.

In fig. 7, the shear rivet fragments 85 are fixed in the passage direction of the hole 9 by retaining ridges 84 projecting transversely to the hole axis B into the widened portion 91 and are secured against falling out. The retaining ridge 84 forms a form-fitting connection element which acts in the passage direction of the opening 9 and is produced during shearing.

In order to prevent the second shear rivet fragments from falling out of the openings 9 of the carrier plate 7 and being fixed, the openings 9 in the carrier plate 7 can also have a widening 91 in the form of a circumferential chamfer in at least one edge region delimiting the contact surface 78, as a result of which in principle a deformation space 92 is formed in the carrier plate 7 which is mirror-symmetrical to the deformation space 92 in the housing 51 relative to the shear plane S. This arrangement is shown in fig. 8 in the same view as fig. 6 as a second variant. However, the mirror-symmetrical configuration of the deformation space 92 is not necessary to ensure functionality. The deformation space may also be smaller or larger than the other deformation space or may have a different geometry.

Fig. 9 shows the sheared state in a similar manner to fig. 7. As in fig. 7, the shear rivet fragments 85 have a retaining ridge 84 located at the upper edge of the rivet shaft 81 in the drawing. Furthermore, the shear rivet fragments 86 located on the right side of the drawing have been plastically deformed before being sheared off, so that the retaining ridge 84 is configured to protrude at the lower edge of the drawing into a deformation space 92 defined by the widened portion 91. As a result, in the opening 9, the shear rivet fragments 86 are held and fixed in a form-fitting manner on the carrier plate 7.

The third variant shown in fig. 10 differs from the embodiment according to fig. 8 in that the widened portion 91 in the housing 51 is a stepped bore with a shoulder 93 projecting with respect to the channel cross-section. As a result, the deformation space 92 is an annular hollow cylindrical shape.

The fourth variant shown in fig. 11 differs from the embodiment according to fig. 8 in that the widened portion 91 in the carrier plate 7 is not configured as a conical chamfer as in fig. 8, but rather a rounding 94 as an edge is configured as an arcuate cross section, the rounding 94 having a radius r of greater than or equal to 0.5 mm.

The embodiment shown in fig. 12 differs from the variant described above in that the shear rivet 8 is designed as a solid rivet. Naturally, the other variants of fig. 1 to 11 can be designed with solid rivets instead of hollow rivets. The person skilled in the art selects the rivet accordingly, so that the shear force selected and predetermined thereby is achieved by means of the selected rivet.

Fig. 13 and 14 show views viewed in the direction of the normal to the contact surface 58 or 78. In the embodiment of fig. 13, the widened portion 91 circulates around the entire circumference of the opening 9, whereas in fig. 14 the widened portion 91 is only partially configured in the circumferential region, wherein, during a collision, the retaining ridge 84 on the shear rivet fragments 85 and/or 86 is plastically deformed by the collision force F. The modification shown in fig. 1 to 12 can be realized by a widened portion and a partially widened portion over the entire circumference. The geometry of the widened portions is thus correspondingly configured over the entire circumference or partially over the circumference, wherein combinations thereof are also conceivable and possible, i.e. one widened portion of one part is configured over the entire circumference and the widened portion of the other part is configured partially over the circumference.

List of reference numerals

1 steering column

2 support unit

21 fastening device

30 steering main shaft

31 inner sheath tube

310 receiving opening

32 fastening part

33 outer sheath unit

4 adjustment drive

41 drive unit

42 thread spindle

43 spindle nut

45 support element

5 energy absorption device

51 casing

510 form-fitting connection element

52 groove

54. 56 energy absorbing element

544. 564 drive the hook

546. 566 abutting portion

57 opening

58 contact surface

59 outer surface

60. 61 coupling element

62 thermoelectric actuator

7 bearing plate

78 contact surface

8 shear rivet

81 rivet shaft

82. 83 rivet head

84 retaining ridge

85. 86 shear rivet fragment

9 opening

91 widened portion

92 space for deformation

93 shoulder part

L longitudinal axis

H vertical direction

S shear plane

Axis of B hole