Steering column assembly

Abstract

14. The steering column assembly of claim 13, wherein the at least one arm of the vehicle is configured to be fixed to a fixed portion of the vehicle and comprises two arms, the arms depending from a base portion to surround the at least one arm of the vehicle, a clamping pin extending through an opening in each arm of the at least one arm of the at least one arm of the vehicle and a slot in the at least one arm of the vehicle, and a clamping mechanism capable of moving between a release position and a clamping position, wherein the at least one arm of the vehicle is configured to be fixed to a fixed portion of the vehicle and comprises two arms, the arms depending from a base portion to surround the at least one arm of the vehicle, the clamping pin extending through an opening in each arm of the at least one arm of the vehicle and a slot in the at least one arm of the vehicle

Description

Technical Field

[0001] The present invention relates to improvements in steering column assemblies. Background Art

[0002] It is known to provide a foldable steering column assembly comprising a steering shaft supported within a steering column shroud. In order to prevent serious injury to the driver in the event of a collision, the steering column should be able to fold when an axial load is applied through the steering wheel, such as in a frontal collision where an unbelted driver is thrown onto the steering wheel.

[0003] A typical foldable steering column assembly includes a telescoping shroud having an outer shroud portion and an inner shroud portion, one end of the inner shroud portion extending into the outer shroud portion. The outer shroud portion may be closer to the steering wheel or further from the steering wheel than the inner shroud portion. A telescoping steering shaft, also having an upper shaft portion and a lower shaft portion, is supported within the shroud by one or more bearing assemblies. The steering wheel is fixed to the upper shaft portion. In some cases, the shroud will not include two parts, but rather the shroud will simply move relative to the bracket.

[0004] The portion of the shroud nearest the steering wheel must be able to move or fold during a collision to allow the steering wheel to move forward relative to the body of the vehicle, but prevent its movement during normal use. The shroud also needs to be secured relative to the body of the vehicle to define the tilt position of the steering wheel. This is typically achieved by a clamping mechanism that secures the shroud to a support bracket, which in turn is secured to the body of the vehicle, possibly to a cross member disposed behind the dashboard of the vehicle. The clamping mechanism may be adjustable to allow fore-and-aft adjustment or tilt adjustment of the steering wheel, or both. The shroud must be able to move in the event of a collision, which can be achieved if it can be disengaged from the clamping mechanism or, in the case of the support bracket, from the body of the vehicle to allow the steering column assembly to be telescopically folded.

[0005] A lever may be provided on one end of a clamping bolt which forms part of the clamping mechanism, and a driver can push or pull the lever to rotate the clamping bolt and thereby operate the clamping mechanism.

[0006] A known steering column assembly comprises a support bracket configured to be fixed to a fixed part of a vehicle and comprising two arms depending from a base portion to surround a shroud, the shroud being located in a gap defined between the two arms. A clamping mechanism comprises a clamping pin extending through an opening in each arm of the support bracket and a slot in the shroud, typically in a track fixed to the top surface of the shroud. In use, the clamping mechanism is movable between a loose position, in which the inclination of the shroud can be adjusted relative to the support bracket, and a clamping position, in which the shroud is fixed relative to the support bracket. This can be effectively achieved if the clamping mechanism applies pressure to the outside of each arm, thereby pushing the arm onto the shroud to clamp the shroud in place. Summary of the invention

[0007] The object of the present invention is to improve the above-mentioned steering column assembly.

[0008] According to a first aspect, there is provided a steering column assembly for a vehicle, the steering column assembly comprising:

[0009] Shield;

[0010] a steering shaft, the steering shaft being supported by a guard;

[0011] a support bracket configured to be secured to a fixed portion of a vehicle and including two arms depending from a base portion to surround the shroud;

[0012] a clamping pin extending through an opening in each arm of the support bracket and a slot in the shroud; and

[0013] a clamping mechanism which is movable between a loose position, in which the shield can be adjusted in inclination relative to the support bracket, and a clamping position, in which the shield is fixed relative to the support bracket; whereby in use the clamping mechanism, in the clamping position, fixes the shield to the two arms of the bracket by pressing the two arms onto the shield,

[0014] Characterized in that at least one arm of the support bracket comprises a plate connected at an upper end to the base portion and having a slot cut in the plate defining a boundary of an elastic flap comprising an opening through which a clamping pin passes.

[0015] The two arms may be provided with respective slots defining a flap, each flap having an opening through which the clamping pin passes.

[0016] The or each slot may be generally U-shaped so as to surround three sides of the flap, with a fourth side connecting the flap to the remainder of the bracket arm.The flap and remainder of the bracket arm may be formed as a single component.

[0017] Each flap may lie substantially in the plane of the surrounding portion of the bracket arm. The region where the flap joins the rest of the bracket arm may lie in the plane of the rest of the bracket arm. This may be achieved during manufacture by stamping the bracket arm with the flap from a single sheet of material. Of course, other forming methods besides stamping may be used, such as cutting a groove to form the flap before or after performing other forming steps.

[0018] The flap, or at least one flap where two flaps are provided, may be permanently deformed when at rest and prior to assembly into the steering column assembly so that a portion of the flap protrudes out of a plane surrounding the bracket arm in a direction towards the other arm. The flap may be resiliently flexible so that when deformed it acts as a spring to store energy which may subsequently be released during release of the assembly.

[0019] The deformation may be such that the flap bends from a location close to the root of the flap where it is connected around the bracket to a free end of the flap.

[0020] The flap may be deflected in use in the manner of a leaf spring to apply a load to the shield.

[0021] The entire flap may be curved or only the portion near the free end may be curved.

[0022] In addition to the permanent deformation of the blade out of the plane surrounding the bracket, the bracket arm can also bend so that the bracket arm also acts as a leaf spring. This means that the blade and the bracket bend when the clamping mechanism is released and flatten or partially flatten when the clamping mechanism is clamped.

[0023] When stationary prior to assembly into a steering column assembly, the spacing between two flaps or between a flap and the opposing arm of the bracket may be shorter than the width of the shroud between the arms when assembled so that in use the flaps are subject to a bending load when the clamping mechanism is released.

[0024] The provision of a bending spring or springs formed by the blade and / or the bracket is advantageous in preventing the shield from fluttering when the clamping mechanism is released.

[0025] If only one tab is provided or deformed out of the plane of the surrounding bracket, it will bias the shield against the other bracket arm, which helps to ensure that the shield does not rotate about its long axis during tilt adjustment or fore-aft adjustment if the clamping mechanism is released.

[0026] The or each flap may be bent along at least one substantially vertical fold line.

[0027] The U-shaped slot may extend along the generally horizontal top edge of the flap, the generally horizontal bottom edge of the flap, and the generally vertical edge of the flap to leave a connection between the flap and the surrounding bracket arm connecting the two ends of the slot.

[0028] The substantially vertical edge of the flap may be located on the side of the flap that is closest to the steering wheel end of the shroud, ie the end that is closest to the steering wheel in use.

[0029] The flap may include a cut-out portion on a side of the opening receiving the clamping pin facing away from the steering wheel.

[0030] The flap may include a second slot defining another flap within the flap. In such an arrangement there may be provided in the bracket arm a first slot defining the flap, which first slot may be generally U-shaped, and a second slot within the flap, which second slot may also be generally U-shaped, with the open end of the second slot facing away from the open end of the first slot. This means that when viewed in cross section the innermost flap and the main length form a Z-shape when deformed out of the plane of the rest of the bracket portion.

[0031] The opening through which the clamping pin passes may include an elongated slot to allow the clamping pin to move up and down the slot when the clamping mechanism is released to achieve tilt adjustment of the steering column assembly.

[0032] The bracket may include a base portion having a central portion located above the shroud and two side wings extending out to define anchor points for securing the bracket to the vehicle body. The central portion of the base portion may include a generally flat plate, and each of the wings may further include a plate extending downwardly away from the plane of the central portion of the base portion at an angle of between 10 and 70 degrees, preferably about 50 degrees, relative to the vertical.

[0033] Each arm may define an outwardly extending lower wing at a lowermost end farthest from the base portion, the lower wing connected to each wing of the base portion. Each lower wing may extend upward at an angle between 10 and 70 degrees relative to the vertical (wherein a lower angle means the wing is closer to horizontal than a higher angle). When viewed in a cross section along the long axis of the shield, the side wings of the base portion, the arms and the lower wing portion may together form a triangular shape.

[0034] The lower wing and the plate forming the arm may comprise a single element joined at a fold line.The arm may be connected to the base portion by one or more welds or other fastening means such as rivets or adhesive.

[0035] The arm may comprise a single layer defined by a plate in which a flap is formed. The flap may also be a single layer, which may comprise a flap within a flap.

[0036] The lower wing and the wing of the base portion may overlap in the area where the bracket is secured to the body so that they are both clamped to the body by the fasteners used to secure the bracket assembly. This means that the joint between the two components does not need to be as strong as it would otherwise be because the fasteners prevent the two components from being pulled or sheared apart when loads are applied to the bracket.

[0037] The clamping mechanism may include a cam mechanism at one end of the clamping pin on the side of the arm opposite the shroud. The cam mechanism may change length between a clamped position and a loosened position to squeeze the bracket arm onto the shroud. An end stop may be provided at each end of the clamping pin, such as a head or nut.

[0038] The cam mechanism may include a fixed cam portion and a moving cam portion. Movement of the rod may be used to rotate the moving cam portion relative to the fixed cam portion. Cam surfaces of the moving cam portion and the fixed cam portion may cause the length of the cam mechanism to change due to rotation.

[0039] The cam mechanism may comprise a portion which fits within an opening in a tab in one of the arms of the support bracket. This portion may prevent the fixed cam portion of the cam mechanism from rotating and may take the form of a block or a pair of dowel pins.

[0040] In the clamped position, the two bracket arms may be compressed between the cam mechanism and opposing sides of the shroud. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

[0042] Figure 1 is a cross-sectional view of an embodiment of a steering column assembly according to the first aspect, viewed along the length of a steering shaft;

[0043] Figure 2 yes Figure 1 A perspective view of an embodiment of wherein the shield and shaft and clamping mechanism are removed for clarity;

[0044] Figure 3 yes Figure 1 a plan view of a bracket arm of the assembly showing the flap and surrounding slot;

[0045] Figure 4 In the first embodiment Figure 3 an enlarged perspective view of the bracket arm of , showing the flap bent slightly out of the plane of the rest of the bracket arm when in a free state;

[0046] Figure 5 Shown is a cross-sectional view along the length of the steering shaft. Figure 4 The lamellar part;

[0047] FIG6(a) is a schematic plan view of an alternative bracket, and FIG6(b) is a cross-sectional view of the alternative bracket along the length of the steering axis; and

[0048] Figure 7(a) and 7(b) 6( a ) and ( b ) for yet another alternative arrangement of the bracket arm. DETAILED DESCRIPTION

[0049] First refer to Figure 1 , a steering column assembly 100 is shown, which includes a shroud 102 that houses a shaft 104. The shaft 104 is configured to be attached to a steering wheel (not shown). The shaft 104 is supported by a bearing assembly (not shown) that allows the shaft 104 to rotate relative to the shroud 102. A support bracket 108 includes two arms 110a and 110b that depend in a substantially vertical direction and provide support and stability to the shroud 102.

[0050] The clamping pin 112 passes through a vertical slot 114 in the support bracket 108 and a horizontal slot 116 in a clamping track 118 of the shroud 102. The clamping pin 112 has a stop 120 at one end that prevents the clamping pin 112 from being pulled through the support bracket 108. At the other end, a cam mechanism 122 that is rotated using a rod 124 allows the effective length of the clamping pin 112, that is, the length of the clamping pin 112 between the cam mechanism 122 and the stop 120, to be changed. The cam mechanism 122 includes a fixed cam portion 126 and a moving cam portion 128 that is rotated by rotation of the rod 124, pushes against the fixed cam portion 126 and extends the length of the cam mechanism 122. The clamping pin and cam and end stops together with the bracket arm and track define a clamping mechanism.

[0051] In the released position of the clamping mechanism, the arm has sufficient freedom of movement to allow adjustment of the fore-aft and tilt positions of the steering column assembly 100 without excessive force by the user. In all figures, the clamping mechanism is shown in the clamped position.

[0052] To move from the loose state to the clamped state, the user rotates the lever 124. The rotation of the lever 124 causes the cam mechanism 122 to extend along the clamping pin 112, so that the cam mechanism 122 extends through the slot 114 in the support bracket 108 and presses on the outside of one of the arms 110a. This arm is pressed into contact with the shield 102. The shield 102 is thus pushed to the right side of the support bracket 108 and presses the other arm 110b against the end stop 120 on the clamping pin, thereby locking the shield 102 in the desired position relative to the support bracket 108.

[0053] The bracket includes a base portion 130 that is generally planar and extends over the top of the shroud 102. Each end of the base portion 130 projects outwardly to define upper wing portions 132, 134. The wings define outboard fixing points 150 for fixing the bracket to the vehicle body. In the example shown, bolts (not shown) can pass through holes 136, 138 in the wings.

[0054] The bracket also includes a respective lower wing 140, 142 associated with each arm 110a and 110b, the lower wing 140, 142 being connected at one end to the upper wing 132, 134 of the base portion so that it is located outside the area where the arm 110a, 110b depends from the base portion, and connected at the opposite end to the bracket arm 110a, 110b at a position spaced from the base portion. The upper wing is inclined downwardly and the lower wing is inclined upwardly when moving away from the shield so that they meet approximately at the midpoint of the height of the bracket arm. The two wings provide two load paths for the force to be transmitted from the bracket arm to the fixed part of the vehicle.

[0055] Figure 2 The bracket assembly 108 is shown in a perspective view with the shield and clamping mechanism removed. Figure 3 A strip of the bracket arm 110a is shown in plan view. These clearly show the provision of a flap 160 cut into the peripheral portion of the bracket arm. The flap is defined by a generally U-shaped slot 161, the open end of the U-shaped slot facing away from the end of the shroud nearest the steering wheel. This defines a hinge line (indicated by the dashed line 162) by which the flap can flex relative to the remainder of the bracket arm. A substantially vertical elongated slot 114 is located in the flap, through which the clamping pin 112 passes.

[0056] The flap 160 is formed as a single component, in this case in a plate forming the bracket arm, and is thus integral with the bracket arm, which means that no additional fixing means are required to fix the flap 160 to the bracket arm 110a. The flap 160 also lies generally in the plane of the surrounding bracket arm, thereby reducing the overall thickness of the bracket arm and flap.

[0057] When at rest, the flap 160 may deform in a variety of ways, such as Figure 4 and 5 , Figure 6(a) and 6(b) as well as Figure 7(a) and 7(b) as shown in the example.

[0058] exist Figure 4 and 5 In the example of FIG. 1 , the flap 160 is a single sheet that is curved along its length from the root where it joins the surrounding bracket to the opposite free edge 10 of the flap 160. This curve is eliminated when the clamping mechanism is clamped, thereby placing a load on the flap 160. When the clamping mechanism is released, the flap 160 returns to a relaxed curved state and, in doing so, applies a light preload to the shield. This helps prevent the shield from excessive movement between the bracket arms.

[0059] exist Figure 6(a) and 6(b) In the example of , the alternative flap 260 is provided with a single bend, but instead of bending away from the plane of the bracket arm 110a at increasing distances from the root, it initially bends outwardly and then bends back toward the plane of the remaining bracket arm. The curve in this example presents a convex surface that contacts the shield, while Figure 5 The embodiment presents a concave surface. Figure 4 and 5 As in the example of , this applies a preload to the shroud.

[0060] Figure 7(a) and 7(b) A more complex arrangement is shown in which a second flap 360a is defined by a second U-shaped slot within flap 360. As shown in Figure 7(b) this presents a Z-shaped bracket arm and flap when viewed in cross-section along the length of the shaft.

Claims

1. A steering column assembly for a vehicle, the steering column assembly comprising: Shield; a steering shaft, the steering shaft being supported by the shield; a support bracket configured to be secured to a fixed portion of the vehicle and including two arms depending from a base portion to surround the shroud; a clamping pin extending through an opening in each arm of the support bracket and a slot in the shroud; and a clamping mechanism movable between a loose position in which the shield can be adjusted in inclination relative to the support bracket and a clamping position in which the shield is fixed relative to the support bracket; whereby in use the clamping mechanism, when in the clamping position, fixes the shield to the two arms of the support bracket by pressing the two arms onto the shield, characterised in that at least one arm of the support bracket comprises a plate connected at an upper end to a base portion of the support bracket and having a slot cut in the plate, the slot defining the boundaries of an elastic flap, the flap comprising an opening through which the clamping pin passes, Wherein the flap is permanently deformed when at rest and prior to assembly into the steering column assembly such that a portion of the flap protrudes out of the plane of the surrounding support bracket in a direction towards the other arm of the support bracket.

2. The steering column assembly according to claim 1, wherein: The two arms are provided with respective slots defining a tab, each tab having an opening through which the clamping pin passes.

3. The steering column assembly according to claim 1 or 2, wherein: The or each flap of the arm and the respective remainder of the arm are formed as a single component.

4. The steering column assembly according to claim 3, wherein: The area where the flap joins the rest of the arm lies in the plane of the rest of the arm. 5 . The steering column assembly of claim 1 , wherein the tab includes a cutout portion on a side of the opening that receives the clamping pin facing away from the steering wheel. 6 . The steering column assembly according to claim 1 , wherein the entire sheet portion is bent or only a portion near the free end is bent.

7. The steering column assembly of claim 1, wherein the arm of the support bracket is curved so that the arm of the support bracket also functions as a leaf spring.

8. The steering column assembly according to claim 1, wherein: The support bracket includes a base portion having a central portion located above the shield and two side wings extending outwardly to define anchor points for fixing the support bracket to the vehicle body, the central portion of the base portion includes a generally flat plate, and each wing also includes a plate located out of the plane of the central portion of the base portion, and wherein each arm defines an outwardly extending lower wing at a lowermost end farthest from the base portion, the lower wing being connected to each wing of the base portion.

9. The steering column assembly according to claim 8, wherein: Each arm can comprise a single layer defined by the plate with a flap formed therein.

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