Steering column arrangement

Abstract

A collapsible steering column assembly, comprising a steering shaft (210) mounted in a steering column shroud, the steering column shroud comprising an upper shroud part (260) and a lower shroud part (270), the upper shroud part (260) being arranged towards the end of the steering shaft (210) closest to a steering wheel (220), and the lower shroud part (270) being arranged towards the end of the steering shaft (210) furthest from the steering wheel (220), the upper shroud part (260) being at least partially arranged within the lower shroud part (270) so that the upper shroud part (260) can telescopically slide into the lower shroud part (270) upon impact, a bracket (300) being fixed to a fixed part of the vehicle in use and comprising two retaining arms (310, 320) being supported by a base part (330). to hang down to encompass the steering column cover, a clamping rail (360) which is detachably fixed to the upper cladding part (260), wherein the clamping rail (360) comprises a slot (315, 325) extending horizontally, a clamping pin (340) extending through an opening in each of the retaining arms (310, 320) of the holder (300) and through the horizontal slot (315, 325) in the clamping rail (300), wherein the clamping pin (340) carries a clamping mechanism which is movable between an unclamped position in which the clamping rail (360) can move freely relative to the clamping pin (340) and a clamped position in which the clamping rail (360) is fixed relative to the clamping pin (340), and characterized in that the clamping rail (360) is fixed to the upper trim part (260) by a deformable tab (700) which protrudes from the upper trim part (260) in order to hook onto a part of the clamping rail (300) which faces the steering wheel end of the steering column trim, and that in the use of an assembly (800) with a cam mechanism in the clamped state, the tab (700) is deformable under a predefined load acting on the upper trim part (260), so that it disengages from the clamping rail (300), thereby enabling the upper trim part (260) to move axially relative to the clamping rail (300) and thus relative to the clamping pin (340) to allow the steering column trim to slide together.

Description

[0001] The present invention relates to improvements in a steering column arrangement having the features of the preamble of claim 1.

[0002] Such a steering column arrangement is known from DE 10 2013 104 958 B3.

[0003] It is known to provide a collapsible steering column assembly 100 with a steering shaft 103 mounted in a steering column shroud. The shroud is telescopic and comprises two parts: an upper shroud part 101 and a lower shroud part 102, the upper shroud part being arranged towards the end of the steering shaft closest to the steering wheel (not shown), and the lower part being arranged towards the end of the shaft furthest from the steering wheel. An end portion of the upper part 101 or of the lower part 102 is slidably arranged within an end portion of the other, so that the shroud can collapsible telescopically upon impact. This telescopic action can also be used to allow the overall length of the assembly to be adjusted, enabling the driver to set the steering wheel reach to a desired position. An example of such an assembly is shown in Fig. 1 shown.

[0004] According to current technology, the upper fairing can slide over the lower fairing section or into the lower section. The second option is preferred, as this allows the steering shaft to be supported by bearings at each end of the upper fairing.

[0005] One object of the present invention is to improve steering column assemblies according to the prior art in order to optimize one or more problems of those designs in which the upper shroud slides into the lower shroud. By providing a column in which the upper shroud is arranged within the lower shroud, the steering column shaft can be mounted directly in the upper tube by bearings at each end of the tube, as in Fig. 1 is supported, resulting in good stiffness. However, with this column type, it is more difficult to integrate an impact energy system that delivers the same force-stroke profile regardless of the initial depth setting position chosen before an impact. It is also more difficult to arrange an impact energy system that incorporates increasingly required features such as: (i) adjustable energy absorption belts (ii) Adaptive energy absorption values ​​to take into account belted or unrestrained drivers and / or drivers with significantly different body weights and vehicle impact speeds (iii) Total energy intake values ​​that are exactly reproducible (for example, to + / -5%).

[0006] The applicant recognized that, for example, when a significant portion of the compression resistance is due to friction, the overall energy absorption is less predictable. A significant source of friction would be a pressing force occurring between the inner and outer tubes when the column is clamped in its depth / height position, which is otherwise advantageous for eliminating play between the cladding components.

[0007] The problem underlying the invention is solved with a steering column arrangement having the features of claim 1. 1. Deformable tab

[0008] According to a first aspect, the invention provides a collapsible steering column assembly with a steering shaft mounted in a steering column shroud, the shroud comprising an upper shroud part and a lower shroud part, the upper shroud part being arranged towards the end of the steering shaft closest to the steering wheel and the lower part being arranged towards the end of the shaft furthest from the steering wheel, the upper part being at least partially arranged within the lower part so that the upper part can telescopically slide into the lower part upon impact, a bracket being fixed to a fixed part of the vehicle in use and comprising two retaining arms hanging from a base part to grip the shroud, a clamping rail which is detachably fixed to the upper cladding part, the clamping rail comprising a slot which is substantially horizontal, a clamping pin which extends through an opening in each of the arms of the bracket and through the substantially horizontal slot in the rail, the clamping pin carrying a clamping mechanism which is movable between an unclamped position in which the rail may move freely relative to the clamping pin and a clamped position in which the rail is fixed relative to the clamping pin, and characterized in that the rail is fixed to the upper fairing part by a deformable tab which protrudes from the upper fairing part in order to hook onto a part of the rail which faces the steering wheel end of the fairing, and that, in the use of the assembly with the cam mechanism in a clamped state, the tab is deformable under a predefined load acting on the upper cover, so that it unhooks from the rail, thereby allowing the upper cover to move axially relative to the rail and thus relative to the clamping pin, in order to allow the steering column cover to slide together.

[0009] The tab can deform by bending under load. The tab may initially be bent and straighten itself when a load is applied.

[0010] The tab can initially extend away from the upper panel, and if it is deformed, it can be flattened onto the upper panel to allow the upper panel to pass under the rail.

[0011] The tab can be fixed to the upper panel by a rivet or a weld. Alternatively, the tab can be integrated into the upper panel and formed by a U-shaped slot in the panel, defining a tongue that is bent out of the plane of the upper panel to form the tab before final assembly.

[0012] A single tab or more than one tab can be provided. If a single tab is provided, it can be positioned vertically above and in the vertical plane, aligned with the central axis of the panel. The tab can extend upwards from the upper panel.

[0013] The opening in each of the arms of the bracket may include an substantially vertical slot, and the clamping mechanism may, in the unclamped position, allow the clamping pin to move freely along the slot to adjust the height of the steering column cover, and, in the clamped state, prevent relative movement to lock the height position.

[0014] Essentially vertical slots and essentially horizontal slots do not refer to slots that extend exactly vertically or horizontally, but rather slots that may deviate by 10 degrees, 20 degrees, or more from the vertical or horizontal. A person skilled in the art recognizes that the vertical slot allows for height adjustment (that is, movement of the steering wheel with a vertical component), and the horizontal slot allows for depth adjustment of the steering wheel (that is, with a horizontal component).

[0015] The assembly may further comprise an energy absorption mechanism which is fixed at a first part to the rail and at a second part to the upper fairing part, wherein the energy absorption mechanism deforms when the upper fairing moves relative to the rail in order to control at least partially the collapsing speed of the steering assembly.

[0016] The energy absorption mechanism can engage the rail with the tab before it is pushed together. The first part of the energy absorption mechanism can engage the rail at the end of the rail furthest from the steering wheel.

[0017] When used with the cam mechanism in the unclamped state, the upper liner and energy absorption mechanism can move together with the rail when the liner's depth is adjusted. The rail and upper liner move together relative to the lower liner. The rail is secured at one end by the deformable tab and at the other by the energy absorption mechanism, and the horizontal slots allow for depth adjustment. When clamped, the relative positions of the ends of the energy absorption mechanism and the rail are the same, regardless of the height and depth settings. Therefore, the deformation of the energy absorption mechanism for a given axial movement of the upper liner relative to the lower liner remains constant, resulting in consistent impact behavior.

[0018] During a compression, which causes a movement of the upper panel relative to the lower panel, the energy absorption mechanism controls the compression force.

[0019] To control the collapsing, the energy absorption mechanism can comprise at least one deformable energy absorption strip with a first and a second end, the first end being attached to the rail on the first part and the second end being attached to the upper cover on the second part.

[0020] The energy absorption mechanism can comprise two adjacent energy absorption strips, each offset to opposite sides of the vertical centerline of the wave. These can be configured as described previously.

[0021] Each strip can be spirally wound before being compressed and unwound during the compression process, with the deformation during unwinding consuming energy. Apart from being clamped at each end, the belts do not otherwise need to be clamped.

[0022] The end of each strip fixed to the rail can be screwed to a plate welded to the rail. The other end can be hooked onto the end of the upper panel.

[0023] The energy absorption mechanism can be designed to provide two different values ​​of energy absorption during a sliding of the upper cladding part when the clamping mechanism is clamped, with a second value being lower than the first value.

[0024] The steering assembly may include selection means for choosing which of the two values ​​to apply during a collision. These can determine which value will apply before the impact, based on information from one or more vehicle-mounted sensors, such as a seatbelt sensor that detects whether the driver is wearing a seatbelt, a weight sensor that determines the driver's weight, a vehicle speed sensor that determines the vehicle's speed, etc.

[0025] The selection tool can include a processor.

[0026] The energy absorption mechanism may include an additional energy absorption belt having a first part that is attached relative to the rail when in the first mode but not in the second, and a second part that is fixed to the upper panel, wherein the additional energy absorption device deforms when in the first mode and does not when in the second mode in order to absorb some of the energy when the panel is pushed together.

[0027] The energy absorption mechanism may include a locking mechanism which, in the first operating mode, is positioned in a first position in which it engages the first part of the additional energy absorption mechanism, and moves to a second position in the second operating mode in which it does not restrain the first part.

[0028] The locking mechanism can be connected to a pyrotechnic device which, when the locking mechanism is actuated, allows it to move from the first position to the second position. The device can be actuated by the selection mechanism.

[0029] The assembly can therefore comprise three belts. The middle one can be quickly deactivated via a pyrotechnic device controlled by the selection mechanism, as determined by factors such as driver weight, vehicle speed, failure to wear a seatbelt, etc. The use of three energy-absorbing belts ensures symmetry, so that their combined resistance is approximately centered in every setting.

[0030] The locking mechanism may include a hole in which a pin of the pyrotechnic device is located, the pin preventing movement of the locking mechanism and moving out of the hole when the pyrotechnic device has been actuated by the selector to select the second operating mode, in which reduced energy absorption is required. For example, if a driver has fastened a seatbelt and the vehicle is moving slowly, less force would be expected to be exerted on the upper fairing to absorb.

[0031] The locking mechanism can comprise a rod that includes a guide slot which receives a guide block, the guide block being fixed relative to the rail and the guide slot extending at an acute angle to the direction of movement of the rail relative to the upper cover, the block guiding the locking mechanism in the second mode to move away from the first part of the additional energy absorption device. During guidance, it can allow the rod to move away from the upper cover so that additional energy belts can pass freely between the upper cover and the rod.

[0032] The guide block can be supported by a guide plate to which the first ends of the attached energy-absorbing straps are fixed. The guide plate can grip the sides of the rod to work in conjunction with the block to control the movement of the locking mechanism. The guide plate can also provide a secure mounting for the pyrotechnic device.

[0033] The straps and guide plate can be positioned at the end of the rail furthest from the steering wheel.

[0034] The clamping pin can be equipped with a head at each end and the clamping mechanism supported by the clamping pin can include a cam mechanism arranged on the clamping pin comprising a fixed cam and a movable cam, the cam mechanism being arranged to increase in length as it moves from an unclamped position to a clamped position.

[0035] The heads can be fixed or adjustable axially along the clamping pin. For example, one or both heads can include a nut that is screwed onto a thread at the end of the clamping pin.

[0036] The cam mechanism can be located between the outside of an arm and one of the heads of the pin.

[0037] The clamping mechanism may also include a rack and pinion block between the cam mechanism and one of the arms.

[0038] In addition to moving the depth and / or elevation block into engagement with teeth on the upper fairing and bracket, the cam mechanism, when clamped, can exert a tensile force on the clamping bolt, which squeezes the arms of the support arm bracket together, and it reduces this force when not clamped to allow the arms to move away from each other, with the arms in turn pressing the outer fairing onto the inner fairing.

[0039] In the clamped position, the rail is pressed onto the support arm. To ensure that the rail cannot move relative to the clamping bolt when clamped to a significant degree, a first rack may be arranged extending along the horizontal slot of the rail. The clamping bolt may support a depth adjustment block, which has an additional rack. A spring is present that pushes the teeth of the cam mechanism apart in the unclamped position. This spring is overcome when the cam mechanism is clamped, so that the teeth of the block engage with the teeth of the rail. This secures the rail in place.

[0040] The rack can be mounted on a plate welded to the rail. The rail itself can comprise a metal casting that is part of the cast upper casing, or it can be a separate metal component welded or otherwise fixed to the upper casing.

[0041] Similarly, to prevent unwanted vertical movement during an impact, a second rack can be arranged extending along the vertical slot in one of the support arms. The clamping bolt can support a height-adjustment block incorporating an additional rack. The same spring pushes the teeth apart when the cam mechanism is not clamped, and this force is overcome when the cam mechanism is clamped. This ensures the rail is fixed at the desired height. A separate spring could be provided to push the teeth apart.

[0042] The two tooth blocks and the cam mechanism can be screwed onto the clamping bolt between an arm and the corresponding fixed head of the bolt to provide a single component stack, with actuation of the cam changing the overall length of this stack. In a modification, the cam could be located at one end of the bolt and the tooth blocks at the other. The same length stack would be present, but it would consist of two sub-stacks, one outside each arm.

[0043] As described, the clamping mechanism has a clamped and a untucked position and, in the clamped position, can press the lower outer panel section onto the upper inner panel section. To provide further control of the compression force, in which tooth retention is provided, the clamping mechanism can be designed to additionally provide a second clamped position in which the pressing force exerted by the arms on the lower panel section is reduced or completely eliminated, while the retention teeth remain engaged. In this secondary clamped position, the overall stack length must be shorter than in the first clamped position but longer than in the untucked position.

[0044] The degree of relaxation of the clamping mechanism between the fully clamped and the secondary clamped position can be chosen so that it is smaller than the height of the teeth, possibly about 1 to 2 mm.

[0045] The clamping mechanism can be designed to automatically move into this secondary clamped position when sufficient force is applied to the upper fairing part in a sliding direction of the steering assembly, without rotating the moving cam of the cam mechanism. In this secondary clamped position, a locking lever operated by the driver remains in the clamped position.

[0046] To achieve the two clamped states, at least one of the interfaces between a first component in a stack of components arranged along the clamping pin, selected from a list comprising the cam assembly, one of the arms of the holder and the tooth blocks, a raised portion and a radially offset recessed portion, and a second adjacent component on which the first component rests, may comprise a side which, in the fully clamped state, engages the raised portion but not the recessed portion, whereby the raised portion is configured to move away from the corresponding side of the adjacent component when a radial load exceeding a threshold is applied to the cam pin, so that the recessed portion subsequently contacts the side of the second adjacent component, thereby reducing the length of the stack of components.

[0047] The term "moving away" means that the component moves radially incrementally relative to the adjacent component, such that the side of the adjacent component moves towards contacting the recessed portion. "Raising" means that the raised portion is closer to the support arm than the recessed portion, where the sides face the support arm. If the stepped sides face away from the support arm, the term "raised" means that the portion is farther from the support arm than the recessed portion. In either case, the component has a greater axial length, measured along the axis of the clamping pin, in a section passing through the raised portion compared to a section passing through the recessed portion.

[0048] In an advantageous arrangement, the clamping bolt can be configured to cause a relative radial movement between the first component and the adjacent second component, causing them to move away from each other when a predefined radial load is applied to the clamping bolt.

[0049] The clamping bolt can be prevented from moving in a direction parallel to the axis of the fairing by a fixing element when the load is below a predefined value. This, in turn, is prevented from moving relative to the bracket by a breakable connection that links the fixing element to the bracket. During use of the steering assembly, when the clamping mechanism is in the clamped state and a load is applied to the upper column in an axial direction exceeding the predefined threshold, the connection shears off. The clamping bolt then moves radially, causing a relative movement between the fixed cam, the movable cam, and / or the height block. This movement reduces the tension in the clamping bolt and thus at least partially releases the adhesion of the outer tube to the inner tube, while maintaining the engagement of the two racks.

[0050] The device may include a pair of stepped surfaces at the interface of one or more of the following pairs of stacked components: between the fixed cam and the movable cam, between the height block (if present) and the depth block (if present), between the height block or the depth block and the holding arm.

[0051] The pairs of stepped surfaces can most preferably be arranged at the interface of the fixed cam and the height tooth block, with both components located in the pressure load path of the cams.

[0052] The clamping bolt may have a square cross-section in one part along its length, which fits through a horizontal opening slot of an anti-rotation plate fixed to the bracket, the size of the slot preventing the bolt from rotating.

[0053] The plate can be positioned between the arms of the bracket. The plate can provide a pivot point that resists movement of this part of the cam bolt towards the axis of the cover when the upper cover slides together.

[0054] The fixed cam section can also have a square hole that engages with the square cross-section of the screw. The use of the square-headed screw and holes prevents the bolt from rotating.

[0055] Since the square cross-section of the clamping bolt prevents rotation of the cam bolt, the retaining arm only needs to prevent it from moving forwards and backwards. On the side of the fixed cam closest to the steering wheel, this can be achieved by contact with an inner vertical side of the slot in the height adjustment toothed plate. On the other side of the fixed cam's base, forward and backward movement can be prevented by contact with a plastic guide block that is melted onto the height adjustment arm.

[0056] To press the arms of the holder inwards, the fixed cam must bridge the gap between the vertical sides of the vertical slot in the tooth block. The cam can be designed as a two-part assembly, in which the actual cam profile is formed as a sintered metal insert, which is subsequently pressed into a non-sintered metal base that has higher flexural strength.

[0057] A horizontal rectangular opening may be present in the guide block, which fits around a shorter rectangular projection on the side arm, allowing some forward / backward movement. 2. ADAPTIVE IMPACT SCHEME.

[0058] According to a second aspect, the invention provides a collapsible steering column assembly with a steering shaft which is supported in a steering column cover by at least one bearing assembly, wherein the cover comprises an upper cover part and a lower cover part, the upper cover part being arranged towards the end of the steering shaft closest to the steering wheel, and the lower part being arranged towards the end of the shaft furthest from the steering wheel, wherein the upper part at least is partially located in the lower part, so that the upper part can slide telescopically into the lower part upon impact, a bracket which, in use, is fixed to a fixed part of the vehicle and comprises at least one arm which hangs down from a base part along the trim in the area where the lower trim part and the upper trim part overlap, and a clamping mechanism which, in a clamped state, secures a rail which is fixed to the upper trim to prevent movement of the upper trim relative to the bracket, and, in a clamped state, allows movement of the trim relative to the bracket. and wherein the rail is further fixed to the upper trim by an energy absorption mechanism acting between the rail and the upper trim part, which is configurable to provide at least two different values ​​of energy absorption during a compression of the steering column in which the upper trim part moves relative to the clamping rail.

[0059] The assembly can switch between the two configurations in response to a signal from an energy input value selection tool.

[0060] Providing an energy absorption device with two values ​​between the rail and the upper cover allows for easy control of the amount of resistance to compression by selecting the appropriate energy absorption value.

[0061] The energy absorption mechanism may include a locking mechanism that engages with part of the additional energy absorption mechanism in the first operating mode, and a second mode in which it disengages from that part.

[0062] The locking mechanism can be connected to a pyrotechnic device which, when activated, moves the locking mechanism from the first mode to the second mode.

[0063] The locking mechanism and the energy absorption element can be attached to the upper part of the fairing using a bracket. 3. CLAMPING BOLT RELAXER.

[0064] According to a third aspect, the invention provides a collapsible steering column assembly with a steering shaft mounted in a steering column shroud by at least one bearing assembly, the shroud comprising an upper shroud part and a lower shroud part, the upper shroud part being arranged towards the end of the steering shaft closest to the steering wheel, and the lower part being arranged towards the end of the shaft furthest from the steering wheel, the upper part being at least partially arranged in the lower part so that the upper part can telescopically slide into the lower part in the event of an impact. a bracket which, in use, is fixed to a fixed part of the vehicle and comprises at least two arms, both of which hang down from a base part along a corresponding side of the trim in the area where the lower trim part and the upper trim part overlap, and a clamping mechanism comprising a stack of components arranged along a clamping bolt, the clamping bolt passing through an opening in each arm of the holder, the stack of components comprising a cam assembly rotatable between an unclamped position in which it has a first axial length and a second clamped position in which it has a second greater axial length, the holding arm being pressed against the fairing when the clamping mechanism is in the clamped position, thereby pressing the lower fairing against the upper fairing, characterized in that the clamping mechanism is designed to additionally provide a second clamped position in which the pressing force exerted by the holder on the lower cladding part is reduced or completely eliminated without a corresponding rotational movement of the cam mechanism.

[0065] Providing the second clamped position reduces or eliminates the friction between the lower and upper trim panels and helps to reduce the variability of the impact force-displacement characteristic and also improves the possibility of the column for a ride-down when the direction of the impact force is significantly offset from the column axis (for example, by more than 30 degrees).

[0066] The component stack can include a tooth height block supported by the clamping pin, wherein the tooth block comprises a first rack which engages in the corresponding teeth fixed relative to the holder in both the clamped and secondary clamped positions, thereby preventing movement of the cover in height, the tooth block being held at a distance from the teeth attached to the holder in the unclamped position.

[0067] The component stack can include a tooth depth block supported by the clamping pin, wherein the tooth depth block comprises a second rack which engages in the corresponding teeth fixed relative to the rail in both the clamped and secondary clamped positions, thereby preventing movement of the cover in depth, the tooth block being held at a distance from the teeth fixed to the rail in the unclamped position.

[0068] The clamping bolt can include a head at each end, with the component stack positioned between a head and one of the support arms.

[0069] The friction removal mechanism of this third aspect of the invention reduces the stress in the clamping bolt under an impact by reducing the stack height of a part of the clamping assembly that is under load when clamped by a small dimension, a reduction of perhaps only 1 to 2 mm.

[0070] To achieve the two clamped states, at least one of the interfaces between a first component in a stack of components arranged along the clamping pin, selected from a list comprising the cam assembly, one of the arms of the holder and the tooth blocks, a raised portion and a radially offset recessed portion, and a second adjacent component on which the first component rests, comprises a side which, in the fully clamped state, engages the raised portion but not the recessed portion, whereby the raised portion is configured to move away from the corresponding side of the adjacent component when a radial load exceeding a threshold is applied to the cam pin, so that the recessed portion subsequently contacts the side of the second adjacent component, thereby reducing the length of the stack of components.

[0071] The term "moving away" means that the stepped component moves radially relative to the adjacent component, such that the side of the adjacent component moves towards contacting the recessed portion. "Raised" means that the raised portion is closer to the support arm than the recessed portion, where the sides face the support arm. If the stepped sides face away from the support arm, the term "raised" means that the portion is farther from the support arm than the recessed portion. In either case, the component has a greater axial length, measured along the axis of the clamping pin, in a section passing through the raised portion compared to a section passing through the recessed portion.

[0072] In an advantageous arrangement, the clamping bolt can be arranged to cause a relative radial movement between the first component and the adjacent second component, causing them to move away from each other when a predefined radial load is applied to the clamping bolt.

[0073] The clamping bolt can be prevented from moving in a direction parallel to the axis of the fairing by a fixing element when the load is below a predefined value. This, in turn, is prevented from moving relative to the bracket by a breakable connection that links the fixing element to the bracket. During use of the steering assembly, when the clamping mechanism is in the clamped state and a load is applied to the upper column in an axial direction exceeding the predefined threshold, the connection shears off. The clamping bolt then moves radially, causing a relative movement between the fixed cam, the movable cam, and / or the height block. This movement reduces the tension in the clamping bolt and at least partially releases the adhesion of the outer tube to the inner tube, while maintaining the engagement of the two racks.

[0074] The device may include a pair of stepped surfaces at the interface of one or more of the following pairs of stacked components: between the fixed cam and the movable cam, between the height block (if present) and the depth block (if present), between the height block or the depth block and the holding arm.

[0075] The pairs of stepped surfaces can most preferably be arranged at the interface of the fixed cam and the height tooth block, with both components located in the pressure load path of the cams.

[0076] The clamping bolt may have a square cross-section in part along its length, which fits through a horizontal opening slot of an anti-rotation plate fixed to the bracket, the size of the slot preventing the bolt from rotating.

[0077] The plate can be positioned between the arms of the bracket. The plate can provide a pivot point that resists movement of this part of the cam screw towards the axis of the cover when the upper cover slides together.

[0078] The fixed cam section may also have a square hole that engages with the square cross-section of the bolt. The use of the square-headed screw and holes prevents the bolt from rotating.

[0079] Since the square cross-section of the clamping bolt prevents rotation of the cam bolt, the retaining arm only needs to prevent it from moving forwards and backwards. On the side of the fixed cam closest to the steering wheel, this can be achieved by contact with an inner vertical side of the slot in the height adjustment plate. On the other side of the fixed cam's base, forward and backward movement can be prevented by contact with a plastic guide block, which is melted onto the height adjustment arm.

[0080] To press the arms of the holder inwards, the fixed cam must bridge the gap between the vertical sides of the vertical slot in the tooth block. The cam can be designed as a two-part assembly, in which the actual cam profile is formed as a sintered metal insert, which is subsequently pressed into a non-sintered metal base that has higher flexural strength.

[0081] A horizontal rectangular opening may be present in the guide block, which fits around a shorter rectangular projection on the side arm, allowing some forward / backward movement. Detailed description

[0082] An exemplary embodiment of the present invention is described below with reference to the attached drawings and as illustrated therein. Fig. Figure 1 shows a cross-sectional view of a steering column arrangement; Fig. Figure 2 shows a corresponding view of an embodiment of a steering column arrangement according to one aspect of the Fig. 2. Invention; Fig. Figure 3 shows a partial view of the assembly made of Fig. 1 before pushing together; Fig. 4 shows a view after a compression; Fig. Figures 5(a) and (b) show the clamping mechanism of the arrangement. Fig. 2, Fig. 3 to Fig. 4; Fig. 6 (a) and (b) show views of the cam mechanism of the clamping assembly in the unclamped and clamped positions; Fig. Figure 7 shows a cross-sectional view of the assembly. Fig. 2 from the top in detail before being pushed together; Fig. 8 shows a view accordingly Fig. 7 after a push-together; Fig. Figure 9 shows a top view of part of the energy absorption mechanism of the steering column assembly. Fig. 2; Fig. Figure 10 shows a view of the energy absorption arrangement before it is pushed together; Fig. 11 shows a view accordingly Fig. 10 after a push-together; and Fig. 12, Fig. 13, Fig. 14 to Fig. 15 shows the assembly transforming from an uncollapsed into a Fig. 12 Fig. 15 moving in a collapsed state to a state in which the pyrotechnic locking mechanism is unlocked to reduce the collapsing force.

[0083] As in Fig. Figure 2 shows a collapsible steering column assembly 200 according to at least one aspect of the present invention, comprising a telescopic steering shaft 210 which carries a steering wheel 220 and connects the steering wheel to a gearbox 230. The steering shaft is mounted in a telescopic steering column housing by two bearing assemblies 240, 250, one bearing assembly 240 near the steering wheel 220 and the other bearing assembly 250 further down on the housing, and can rotate freely about its axis to allow the steering wheel to be turned.

[0084] The fairing comprises an upper fairing part 260 and a lower fairing part 270. Each part is tubular and encloses a hollow, elongated tube. The upper fairing part 260 is positioned toward the end of the steering shaft closest to the steering wheel 220, and the lower part 260 is positioned toward the end of the shaft furthest from the steering wheel 220. The end of the upper part furthest from the steering wheel is a sliding fit within the end of the lower part closest to the steering wheel, allowing the upper part to slide telescopically into the lower part upon impact. As shown, approximately half of the upper tubular part fits into the lower tubular part.

[0085] The fairing 260, 270 is attached to the body. As shown, it is attached at one lower end through the gearbox at a pivot point 280.

[0086] Approximately halfway along the fairing, it is detachably attached to a bracket 300, which, during use, is fixed to a rigid part of the vehicle (not shown). For clarity, the bracket 300 is shown in the Fig. 2 omitted and is best in Fig. 5 and Fig. 7, Fig. 8; it comprises two arms 310, 320 that hang down from a base part 330 along the corresponding sides of the panel in the area where the lower panel part and the upper panel part overlap. Each arm 310, 320 in this embodiment includes an opening, in this example an elongated, substantially vertical slot 315, 325, through which a clamping pin or bolt 340 passes. This clamping pin 340 also passes through an elongated, substantially horizontal slot 350 in a rail 360 that is fixed to the top of the upper panel. This rail is best located in Fig. 3 and Fig. As can be seen in Figure 4 of the drawings. The rail extends through a slot in the upper part of the lower panel so that it runs above the lower panel between the arms of the bracket 300. The clamping pin 340 carries a clamping mechanism designed such that, in the unclamped state, the clamping pin 340 can move up and down in the vertical slots 315, 325 and along the horizontal slot 350 in the rail 360 to allow adjustment of the panel in height and depth. In the clamped state, the upper panel is fixed relative to the bracket to lock the height and depth positions.

[0087] As in Fig. 5 and Fig. Figure 7 shows that the clamping pin 340 has a square cross-section and passes through a vertical slot 375 in an anti-rotation plate 370, which hangs from the mounting base 330 approximately midway between the arms 310 and 320. The width of the clamping pin and the slot 375 are chosen such that the slot in the anti-rotation plate prevents the clamping pin 340 from rotating.

[0088] The cover 260, 270 is locked in position by reducing the length of the portion of the clamping bolts 340 located between the retaining arms 310, 320 by actuating a clamping mechanism. In this embodiment, the clamping pin has a head 341, 342 located at each end of the clamping bolt. A stack of components (shown in Fig. 7 (through the curved clamp) is arranged along the clamping bolt 340 between one of the arms 320 and the adjacent head 342, and the overall length of this stack changes when the clamping mechanism moves between the clamped and unclamped positions. The change in length alters the length of the clamping bolt 340 that protrudes from one of the support arms 320, which in turn changes the length of the clamping bolt 340 that can extend between the support arms. Fig. 5(a) and Fig. Figure 5(b) shows the change from the length L1 of the bolt between the arms in the clamped state to the length L2 in the unclamped state.

[0089] To provide a locking action in the clamped state, an arm 320 is equipped with a rack 500 extending along the vertical slot, and the component stack includes a toothed block or plate 510 located between the arm and the head 342 of the clamping pin 340. The block or plate carries a second rod with complementary teeth facing the first rod 500. A spring 520 pushes the block 510 away from the arm 320 when the clamping mechanism is not clamped and is compressed when it is clamped, causing the teeth of the two rods to mesh.

[0090] A second rack 530 is arranged on a plate that is fixed to the clamping rail 360 along the horizontal slot 350, and the component stack includes a second tooth block or tooth plate 540, which is arranged on the clamping pin 340 that is fixed to the upper cover part and extends through a slot into the lower cover part. This second block is also pushed away from the teeth by the spring 520 when the assembly is not clamped.

[0091] To generate the required clamping force, the stack includes a cam mechanism screwed onto the clamping pin 340 between the height block 510 and the fixed head 342. The cam mechanism comprises a fixed cam 600 and a movable cam 610. The movable cam is attached to a lever (shown in Fig. 5 (a) and Fig. 5 (b)) fixed, which allows a user to rotate the movable cam around the cam screw. The fixed cam does not rotate because the fixed cam has a square hole and is set on a square cross-section of the clamping pin 340, so the fixed cam cannot rotate. The movable cam has a larger round hole, so it can rotate.

[0092] Rotating the clamping lever changes the overall length of the cam mechanism between a minimum length in the unclamped state and a maximum length in a clamped state. The length is measured along the axis of the clamping pin. This is in Fig. 6(a) and Fig. 6 (b) shown for the unclamped and clamped positions respectively.

[0093] In its longest position, the cam mechanism 600, 610 pushes the head 342 of the pin 340 away from the holder. The other head 341 engages the other arm 310 of the holder and attempts to counteract the movement of the head 342 away from the holder. As a result, in the clamped state, the cam mechanism exerts a force between the fixed head 342 and the arm 320, which forces the tooth blocks into engagement with the corresponding height and depth racks. This force further compresses the two arms of the holder, pressing the outer tube of the casing onto the inner tube.

[0094] As in Fig. 7 and Fig. Figure 8 shows a guide block 550 that fixes the fixed cam relative to the support arm. The block 550 is normally fixed to the support arm by a shear pin 560. The guide block prevents lateral movement of the fixed cam and thus also prevents lateral movement of the clamping pin 340, although the vertical slot in the arm is otherwise slightly oversized to allow this movement. As explained below, the shear pin 560 can shear under load to allow a small degree of radial movement of the clamping pin 340, which rotates about the slot in the anti-rotation plate 370. This movement causes a raised portion of the side of the fixed cam to move away from a corresponding side of the height tooth plate, and vice versa, thereby reducing the overall thickness of the fixed cam and the height tooth plate.When this occurs, the tension in the clamping bolt decreases, but the teeth remain engaged. The reduction is sufficient to eliminate the pressing force of the outer tube on the inner tube, but not enough to create excessive play.

[0095] Fig. Figure 7 shows the steering column assembly in the fully clamped position before pin 560 shears off, and Fig. Figure 8 shows the clamping mechanism in the so-called secondary clamped position after the pin has sheared off. In this position, the teeth of the depth and elevation rods remain engaged, but the length of the clamping pin between the two retaining arms has increased slightly, thus reducing the degree of compression between the two panels.

[0096] This arrangement of the clamping mechanism makes it possible to eliminate the friction between the tubes, which is present due to the actuation of the clamping lever and the cam mechanism, when an impact occurs. As in Fig. 3 and Fig. As shown in Figure 4 of the drawings, the clamping rail 360 is fixed to the upper cover 260 at one end closest to the steering wheel by a fixing tab 700. The tab is hooked around the end of the rail facing the steering wheel. In normal use (shear pin 560 not broken, clamping mechanism either clamped or not clamped), the tab 700 ensures that the rail 360 does not move axially relative to the upper cover 260 in any direction towards the steering wheel. The tab 700 can deform when a force exceeding a predefined value is applied to the upper cover, allowing the upper cover to move relative to the rail and pass under the rail. This allows the cover to be compressed while the rail remains clamped to the clamping pin and thus fixed in position relative to the bracket.

[0097] More precisely, the movement of the rail flattens the hook tab 700 downwards towards the main body of the upper panel. This is in Fig. 4 shown.

[0098] The clamping rail 360 is also attached to the upper trim panel at the end furthest from the steering wheel by an energy absorption mechanism 800, as can best be seen in the figure. This mechanism 800 Fig. Component 9 controls the 360° movement of the rail relative to the cover when a high axial load acts on the upper cover, causing the steering column assembly to telescopically collapse. As the rail moves relative to the cover, the energy absorption mechanism deforms, and this deformation absorbs the energy.

[0099] The energy absorption mechanism is best understood in Fig. 9, Fig. 10, Fig. 11, Fig. 12, Fig. 13, Fig. 14 to Fig. 15 of the attached drawings can be seen. Fig. Figure 9 shows the construction group 800 in a top view, while Fig. 10, Fig. 11, Fig. 12, Fig. 13, Fig. 14 to Fig. Figure 15 shows the assembly at various stages of the steering column assembly's compression. As explained below, a key feature of this part of the assembly is that the energy absorption mechanism delivers the same force-stroke profile regardless of the initial depth setting position selected prior to an impact.

[0100] The energy absorption mechanism comprises three wound energy absorption belts 810, 820, 830 arranged side by side. The axis of each belt is perpendicular to the axis of the cover, with the windings arranged essentially in a vertical plane. All three belts 810, 820, 830 are anchored at one end to a plate 840, which is attached to the upper cover 260. The other ends of the outer two belts are fixed to the rail 360 by screws 850, and the other end of the middle belt is optionally fixed to a locking mechanism 860 attached to the rail, depending on which of the two different energy absorption modes the assembly is in. When the upper cover and the clamping rail with the clamping mechanism in the secondary clamping position move relative to each other, the outer two energy absorption belts unwind themselves and absorb energy.The inner winding functions in the same way when it is fixed to the locking mechanism; however, when it is released from the locking mechanism, it does not unwind and plays no role in absorbing the impact energy.

[0101] The locking mechanism 860 can be prevented from moving from a position in which it engages the inner wound belt 820 by a pyrotechnic device 870, which is fixed to a holder that is in turn fixed to the clamping rail. The pyrotechnic device 870 retracts a pin 880, which is normally located in a hole in the locking mechanism 860, to prevent the locking mechanism from moving relative to the clamping rail 360. When fixed by the pin 870, the end of the inner belt 820 is blocked against movement by the locking mechanism. Fig. Figure 10 shows the inner winding before it is pushed together and Fig. Figure 11 shows the winding as it unwinds during the relative movement of the upper panel and rail.

[0102] As in Fig. 9, Fig. 10, Fig. 11, Fig. 12, Fig. 13, Fig. 14 to Fig. As shown in Figure 15, the locking device 860 is mounted on an angled rectangular projection 890 on one side of a support arm. This projection, which is shorter than a corresponding opening in the locking device, causes the locking device 860 to slide upwards and forwards under load (see dotted arrows on the right in Figure 15). Fig. 13) when the pin of the pyrotechnic device is removed. This sliding process occurs because the end of the non-engaged energy-absorbing strap presses against the horizontal flange of the locking mechanism. A point is quickly reached where the end of the inner strap can move forward unimpeded under the flange of the raised locking mechanism. This movement is in Fig. 12, Fig. 13, Fig. 14 to Fig. 15 shown.

[0103] The pyrotechnic device 870 removes the pin 880 in response to a signal from a controller, which may vary according to parameters such as the speed of the vehicle and whether or not the driver is wearing a seatbelt.

[0104] The following describes the operation of the steering assembly before and after an impact event.

[0105] When the driver wants to adjust the steering for reach or rake, the clamping lever is turned to move the cam mechanism to its shortest length. The springs push the racks to the side, and the fairing can be adjusted as desired. The clamping lever is then turned to move the cam mechanism to its longest length, compressing the springs and bringing the racks together. This also presses the lower fairing onto the upper fairing, eliminating any radial play between the fairings.

[0106] Under normal use, when no axial load acts on the upper cover or only a light load is applied, movement of the cover is prevented by the clamping mechanism. The force is transferred to the holder via the breakable pin.

[0107] When a large axial force acts on the upper trim panel in a direction away from the steering wheel, as occurs in a crash where a driver is thrown against the steering wheel, the upper trim panel moves slightly, and this movement causes the pin to shear off. This, in turn, allows further movement of the fixed cam relative to the moving cam until it disengages, releasing the clamping tension that creates friction between the outer and inner trim panels. The clamping mechanism moves into the secondary clamped position, in which the lower trim panel is no longer pressed against the upper trim panel. This eliminates the friction between the two trim panels as the upper trim panel continues to move.

[0108] Once the pin shears off, the clamping bolt and rail move axially by approximately 4 mm. The clamping bolt remains engaged with the teeth of the rail, preventing the rail from moving axially relative to the clamping pin, thus stopping the movement as it is blocked by the retaining arms.

[0109] As the upper column continues to move, unimpeded by the friction between the upper and outer columns, the end of the fixed rail deforms the tab as the upper tube moves further down towards the gearbox. This deformation of the tab absorbs some of the impact energy. Once this deformation is overcome, the upper tube continues to move and begins to deform the energy-absorbing straps.

[0110] In a normal, low-energy impact, all three straps deform to absorb energy. The middle strap is attached to the upper tube and has a section that engages with the locking mechanism, which in turn is attached to the rail. The rail cannot move because it is fixed to the pin.

[0111] The outer straps are attached to the rail and the upper column and also deform.

[0112] In the event of a minor impact, the locking mechanism is released and can slide out of the way, allowing the middle strap to unhook from the locking mechanism and thus move as a whole with the upper column without contributing to energy absorption.

[0113] The shearing of the guide block pin represents the initial breakaway under impact and results in a forward movement of the steering wheel of approximately 4 mm. The initial impact must overcome the strength of the pin as well as the tube-to-tube clamping friction. After breakaway, the latter disappears, and the entire impact force is concentrated on the fusible tab that secures the clamping holder to the inner tube. If the clamping friction between the tubes is 1,000 N, then for a specified total breakaway force (for example, 5,000 N), the shear strength of the pin must be specified at 4,000 N, and the strength of the tab must be 5,000 N. Under a 5,000 N load, the tab is only subjected to 4,000 N before the pin fails, as the tube friction consumes the remaining 1,000 N. Only after the tab breaks free is it subjected to the full force of 5,000 N and fails, which leads to the actual breaking free.This ensures the correct sequence.

[0114] The energy-absorbing straps are wound around themselves and do not need to slide over anvils. Therefore, there is no frictional force component from the energy-absorbing straps when they deform (i.e., straighten) upon impact. The impact force is entirely attributable to the deformation energy absorbed by the material.

[0115] When the center energy absorption strap is released from the locking mechanism, its compact coiled shape means that it remains within the installation space during the impact stroke.

[0116] The pyrotechnic device only needs to move (axially) by the amount of the depth adjustment stroke. The energy absorption belts can pass underneath it. The support arm of the pyrotechnic device is designed to be as narrow as possible to ensure that the maximum width is available for the energy absorption belts.

Claims

A collapsible steering column assembly, comprising a steering shaft (210) mounted in a steering column shroud, the steering column shroud comprising an upper shroud part (260) and a lower shroud part (270), the upper shroud part (260) being arranged towards the end of the steering shaft (210) closest to a steering wheel (220), and the lower shroud part (270) being arranged towards the end of the steering shaft (210) furthest from the steering wheel (220), the upper shroud part (260) being at least partially arranged within the lower shroud part (270) so that the upper shroud part (260) can telescopically slide into the lower shroud part (270) upon impact, a bracket (300) being fixed to a fixed part of the vehicle in use, and comprising two retaining arms (310, 320) being supported by a base part (330). to hang down to encompass the steering column cover, a clamping rail (360°).which is detachably fixed to the upper trim part (260), wherein the clamping rail (360) comprises a slot (315, 325) extending horizontally, a clamping pin (340) extending through an opening in each of the retaining arms (310, 320) of the holder (300) and through the horizontal slot (315, 325) in the clamping rail (300), wherein the clamping pin (340) carries a clamping mechanism that is movable between an unclamped position in which the clamping rail (360) can move freely relative to the clamping pin (340) and a clamped position in which the clamping rail (360) is fixed relative to the clamping pin (340), and characterized in that the clamping rail (360) is fixed to the upper trim part (260) by a deformable tab (700) which projects from the upper trim part (260) to to hook onto a part of the clamping rail (300) that faces the steering wheel end of the steering column cover,and that, in the use of an assembly (800) with a cam mechanism in the clamped state, the tab (700) is deformable under a predefined load acting on the upper trim part (260), so that it disengages from the clamping rail (300), thereby enabling the upper trim part (260) to move axially relative to the clamping rail (300) and thus relative to the clamping pin (340) to allow the steering column trim to slide together.

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