CN108146491B

CN108146491B - Telescopic but non-adjustable steering column assembly

Info

Publication number: CN108146491B
Application number: CN201711261631.9A
Authority: CN
Inventors: N·戴维斯; H·G·金斯顿-琼斯
Original assignee: TRW Ltd
Current assignee: TRW Ltd
Priority date: 2016-12-02
Filing date: 2017-12-04
Publication date: 2022-12-20
Anticipated expiration: 2037-12-04
Also published as: GB2557256A; GB2557256B; GB201620467D0; CN108146491A

Abstract

A retractable but non-adjustable steering column assembly for a vehicle, comprising: a support bracket for fixing to a fixed portion of a vehicle, the support bracket including an integrally formed guide portion; and a tubular shroud portion supporting the steering column shaft, the tubular shroud portion being fixed relative to and at least partially within the guide portion in normal use. In the event of a collision, the tubular shield part is moved relative to the longitudinal axis of the tubular shield part by means of a support bracket and is guided axially and controlled rotationally relative to the longitudinal axis of the tubular shield part. The support bracket is integrally formed as an extruded part, and the tubular shield part may have a polygonal cross-section.

Description

Telescopic but non-adjustable steering column assembly

Technical Field

The present invention relates to improvements in telescopic but non-adjustable steering column assemblies.

Background

Many types of steering column assemblies are known. While adjustable steering column assemblies are commonplace, it is desirable to use non-adjustable assemblies where limitations are imposed such as weight, cost and packaging. However, in order for such an assembly to have acceptable characteristics in a crash, it is necessary to even provide a non-adjustable steering column assembly with the ability to: the non-adjustable steering column assembly moves in response to an impact from the body of the driver to prevent or limit injury to the driver.

A known non-adjustable steering column assembly includes a support bracket and a shroud that receives a steering column shaft. One end of the shaft is connected to a hand wheel and the other end may be connected to the wheels of the vehicle via a power steering system. The support bracket is attached to a fixed portion of the vehicle and supports the shroud so that the steering column shaft is located in a desired position.

In these known assemblies, the support bracket is made so that it can be detached from the fixed part of the vehicle. By doing so, the shroud or steering column tube of the steering column assembly is allowed to telescope or deform so that when impacted by the driver during a collision, the shroud or steering column tube and the support bracket move with the driver's body, thereby limiting potential injury to the driver. However, applicants have appreciated that such assemblies may not be suitable for all applications.

Disclosure of Invention

According to the present invention there is provided a telescopic but non-adjustable steering column assembly for a vehicle comprising: a support bracket for fixing to a fixed portion of a vehicle, the support bracket including an integrally formed guide portion; and a tubular shield portion supporting the steering column shaft, the tubular shield portion being fixed relative to the support bracket in normal use; wherein, in case of a collision, the tubular shield part is moved relative to the longitudinal axis of the tubular shield part by a support bracket and is axially and controlled rotationally guided relative to the longitudinal axis of the tubular shield part.

By "non-adjustable" is meant that the steering column assembly has no user operable adjustment to reach the overall length-or rake angle-of the steering column assembly.

The term "crash" is intended to include all events surrounding the initial crash event, including, but not limited to, any effect of the initial crash, such as a driver impact on the steering column assembly.

Since the support bracket remains fixed to the fixed part of the vehicle and provides a guide for the tubular shroud portion, the present steering column assembly can be telescoped in a more controlled manner than is possible using known non-adjustable steering column assemblies. The guiding of the tubular shield portion may also ensure that the energy absorbed during the telescoping of the steering column is managed in a safe and controlled manner.

The support bracket may further include a connection portion for fixing to a fixing portion of the vehicle.

The guiding portion has a length sufficient to allow sufficient gripping of the tubular shield portion and sufficient guiding of the tubular shield portion during a telescopic stroke. The extent to which the tubular shield portion is clamped will be set to a prescribed level in order to provide a suitable level of friction between the tubular shield portion and the guide portion of the support bracket during the telescopic stroke.

The support bracket may be integrally formed as one piece.

The tubular shroud portion and the guide portion may be in contact with one another such that, in use, a reaction force is generated between the tubular shroud portion and the guide portion, the reaction force having components in orthogonal directions in a plane perpendicular to a longitudinal axis of the tubular shroud portion. The reaction force may have a positive component and a negative component in each direction.

The reaction force may prevent translational movement of the tubular shield portion in a plane perpendicular to the longitudinal axis of the tubular shield portion and/or relative rotation of the tubular shield portion and the guide portion.

The guide portion of the support bracket may be deformable such that it may be fastened around the tubular shield portion, thereby ensuring that tolerances may be adjusted and that the tubular shield portion may be held in its operative position.

The guide portion of the support bracket may comprise a flexing element for enabling adjustment of the guide portion. The flexure element may have a relatively smaller thickness than the remainder of the guide portion.

The tubular shield portion may have a non-circular cross-section in a plane perpendicular to its longitudinal axis, and preferably has a polygonal cross-section. Preferably, the guide portion and the inner column tube of the support bracket have a geometrically similar shape, or a substantially geometrically similar shape, to the tubular shroud portion. The polygonal cross-section may be octagonal or substantially octagonal.

By "geometrically similar" is meant that the guide portion and the tubular shield portion have the same shape, i.e. one is a scaled image of the other. "substantially geometrically similar" refers to those shapes that include: that is, most of the shapes are similar, while other non-salient features are different.

Preferably, the guide portion of the support bracket may comprise an elongated bearing surface extending in the axial direction of the tubular shield portion, on which the tubular shield portion slides during a collision. Thus, the tubular shield part may be guided in a specific direction.

A plurality of elongate support surfaces may be provided which complementarily engage corresponding elongate support surfaces on the tubular shroud portion.

In normal use, the tubular shroud portion may be secured within the guide portion of the support bracket by at least one frangible pin configured to break in the event of a collision.

The telescopic but non-adjustable steering column assembly may further comprise an energy absorbing member for absorbing energy during telescoping of the steering column assembly.

The energy absorbing member may be an energy absorbing band comprising a proximal end attached to one of the tubular shield portion and the support bracket.

The telescopic but non-adjustable steering column assembly may further comprise an anvil attached to the other of the tubular shroud portion and the support bracket around which the energy absorbing band is deformed during telescoping.

The anvil may be a bolt, preferably a bolt passing through the support bracket. The bolt may be a clamping bolt which allows the support bracket to be tightened around the tubular shroud portion. This tightening may remove the clearance and set the level of friction between the guide portion of the support bracket and the tubular shield portion.

The support bracket including the guide portion may be manufactured through an extrusion process.

The assembly may further comprise an inner post tube which may be received within the tubular shroud portion, the tubular shroud portion thus forming an outer post tube. The inner post tube may provide additional guidance of the tubular shield portion during telescoping, if desired.

Drawings

The invention will now be described in detail with reference to the accompanying drawings, in which:

figure 1 is a perspective view of a first angle of a retractable but non-adjustable steering column assembly according to the present invention;

FIG. 2 is a perspective view of a second angle of the telescoping but non-adjustable steering column assembly of FIG. 1;

FIG. 3 is a side view of the telescoping but non-adjustable steering column assembly of FIG. 1 showing line B-B;

FIG. 4 is a cross-sectional view of the non-adjustable steering column assembly of FIG. 3 along line B-B;

figure 5 is a side view of a second embodiment of a telescopic but non-adjustable steering column assembly comprising an inner column tube.

Detailed Description

Referring to the drawings, there is shown a steering column assembly 100 comprising a support bracket 102, a tubular shroud portion 104, and a shaft 106. The support bracket is fixed to a fixed part of the vehicle (not shown) by two fixing points 108. Bolts may be used to secure the support bracket 102 to the vehicle, the bolts passing through the securing points 108. However, other means of connecting the support bracket 102 to the vehicle with or without the anchor point 108 may be used. Thus, the fixation points 108 may help define the connecting portion of the support bracket 102, while the rest of the support bracket 102 is referred to as the guiding portion 114.

One or more bearing assemblies 110 are positioned between the tubular shroud portion 104 and the shaft 106 to provide such support and movement. A sensor cover 112 is provided to be fixed to the lower end of the tubular shield portion, and a steering angle position sensor (not shown) may be covered by the sensor cover.

The support bracket includes an integrally formed guide portion 114, the guide portion 114 supporting the tubular shroud portion 104 in a fixed position to prevent relative movement. The shaft 106 is supported by the tubular shield portion 104 such that the shaft 106 can produce rotational movement relative to the tubular shield portion 104. Thus, this embodiment of the tubular shield portion 104 is formed from a single component having a cross-sectional profile that is complementary to the profile of the guide portion of the support bracket 102.

The tubular shield portion 104 is shaped such that when moved relative to the guide portion 114 during a collision, the tubular shield portion 104 is axially and rotationally guided by the guide portion 114. Furthermore, due to the non-circular cross-section of both the tubular shroud portion 104 and the guide portion 114 of the support bracket 102, the tubular shroud portion 104 is prevented from rotating relative to the support bracket 102 during telescoping of the steering column assembly 100. At the end of the tubular shroud portion 104 furthest from the sensor cover 112, the tubular shroud portion 104 includes a portion having a circular cross-section that includes one of the support assemblies 110 that support the shaft 106. The circular portion of the tubular shield portion 104 may be manufactured by swaging or machining.

The tubular shield portion 104 of the present embodiment has a substantially octagonal cross-section along a majority of its length, including the portion received within the guide portion 114, perpendicular to the longitudinal axis of the tube. An elongated support surface 116 is thus provided on the outer surface of the tubular shroud portion 104 and on the inner surface of the guide portion 114. These bearing surfaces 116 serve to allow relative sliding movement between the tubular shield portion 104 and the guide portion 114. Importantly, the bearing surface 116 should allow for a prescribed sliding movement of the tubular shroud portion 104 relative to the guide portion 114 when movement is permitted. Some friction may be desired and set to assist in controlling telescoping, which friction may be provided using a clamping bolt 132, the clamping bolt 132 having a nut 136 at one end and thus may be tightened to remove any clearance between the tubular shroud portion and the guide portion 114 of the support bracket 102. This is not necessarily required as other elements may be used to provide this functionality.

The bearing surfaces 116 contact each other such that a reaction force is generated between the guide portion 114 and the tubular shroud portion 104.

The reaction force sufficiently constrains the tubular shroud portion 104 so that it is axially guided by the guide portion 114. More specifically, the tubular shield portion 104 of the illustrated embodiment is prevented from rotating relative to the support bracket 102 in a plane perpendicular to the longitudinal axis of the tubular shield portion 104. The tubular shield portion is also prevented from rotating relative to the support bracket 102. However, in other embodiments, it may be desirable to allow some controlled or predetermined relative rotation of the tubular shroud portion 104 and the support bracket 102.

In order for the reaction force between the tubular shield portion 104 and the guide portion 114 to prevent the tubular shield portion 104 from translating in a plane perpendicular to its longitudinal axis, the reaction force generated between these two components should have a force component in the orthogonal direction in said plane. By having a positive and a negative component in both orthogonal directions, significant relative translation can be avoided.

Relative rotational movement may be permitted if the reaction force changes direction during telescoping of the steering column assembly during a collision (for example due to the tubular shroud portion and/or the guide portion having a non-uniform shape along its length-i.e. one or both of the tubular shroud portion and the guide portion may twist along their respective longitudinal axes). However, the motion should be constrained so that it is sufficiently controlled to be predictable in its telescopic characteristics.

Between a number of bearing surfaces 116 of the guide portion 114, a flexure element is provided, formed by two extending portions 134 of the support bracket 102. These flexing elements allow limited deformation of the guide portion 114 such that tolerances and clearances between the guide portion 114 of the support bracket 102 and the tubular shroud portion 104 may be adjusted.

The longer length of the support bracket 102 also ensures that the guidance of the tubular shield portion 104 by the guide portion 114 is smooth and unaffected by non-axial telescoping forces that might otherwise cause the tubular shield portion 104 to snag or drag on the inner surface of the guide portion 114 during telescoping. In conventional steering column assemblies, a separate inner column tube is normally required in order to provide sufficient bearing length to provide the guided movement provided by the present support bracket alone. Thus, the solution of the present invention has a reduced number of parts compared to conventional steering column assemblies that require an inner column tube, and is therefore lighter and easier to manufacture.

Although the depicted embodiment is octagonal, the tubular shroud portion 104 and the guide portion 114 may be provided with cross-sections of different shapes, such as substantially heptagonal, hexagonal, pentagonal, square, or any other shape. Tubular shield portions 104 and guide portions 114 having different cross-sections may also be used, as long as the shape used still provides both axial and rotational guidance of the tubular shield portion 104. The additional bearing surface 116 provided by the multi-faceted tubular shroud portion 104 adds to the guiding feature of the steering column assembly 100.

While the present embodiment utilizes the cross-sectional shape of the tubular shield portion 104 and the guide portion 114 to provide the guide feature, such guide may also be provided by other means, such as providing a channel through which a portion of the tubular shield portion slides. The constraint of rotation may also be provided in other ways known to the person skilled in the art.

In normal use (i.e. prior to any impact causing the steering column to telescope), the tubular shroud portion 104 is held axially in position relative to the support bracket 102 by the clamping force of the guide portion 114 around the tubular shroud portion 104. The separation may be additionally controlled by two frangible pins 118, the two frangible pins 118 passing through holes 120 in both the support bracket 102 and the tubular shroud portion 104. The frangible pin 118 fits tightly within the bore 120, thus eliminating any slack or play in the axial direction. Upon application of a strong force, such as that generated during a collision, the frangible pin 118 is configured to shear break at the boundary between the tubular shroud portion 104 and the support bracket 102, thereby allowing the tubular shroud portion 104 and the support bracket 102 to move axially relative to each other. In this embodiment, the frangible pins 118 are preformed so that they can be made in a single step without any overmolding or other additional manufacturing processes.

If desired, a securing member other than the frangible pin 118 may be used. These securing members may comprise resins or other materials that may be relied upon to fail upon application of a particular force, or any other frangible securing means. Alternatively, a system may be provided that uses only friction to provide fixation. Further, a greater or lesser number of frangible pins 118 may be used depending on the respective requirements and other design considerations.

Once the tubular shroud portion 104 is able to move axially relative to the support bracket 102, it is desirable to manage energy dissipation and telescoping within the steering column assembly 100. Thus, an energy absorbing band 122 is used, the deformation of which absorbs energy during telescoping of the steering column assembly 100 (in particular, as the tubular shroud portion 104 moves relative to the support bracket 102).

The proximal end 124 of the energy absorbing band 122 is preferably secured to the tubular shield portion 104 by welding. The energy absorbing band 122 is then wrapped around an anvil 126 separate from the tubular shroud portion 104 (in this embodiment, the anvil is secured to the support bracket 102), and a distal end 128 of the energy absorbing band 122 extends in a direction parallel to the length of the tubular shroud portion 104. The energy absorbing band 122 has a shape similar to a tuning fork, having a proximal end 124 and two distal ends 128. This allows the energy absorbing band 122 to sit in a symmetrical fashion, with one distal end 128 disposed on either side of the proximal end 124 of the energy absorbing band 122 prior to deformation.

As the tubular shield portion 104 moves relative to the support bracket 102, the energy absorbing band 122 is also displaced due to its connection to the tubular shield portion 104 and will therefore deform around the anvil 126 (as the anvil 126 remains stationary relative to the support bracket 102). This deformation will absorb the energy required for plastic deformation of the energy absorbing band 122, thereby controlling the energy dissipation and telescoping characteristics of the steering column assembly 100. Suitable materials for the energy absorbing band 122 are well known to those skilled in the art, but may include metals and other sufficiently ductile materials. The energy absorbing band 122 should preferably be longer than the maximum relative movement of the tubular shield portion 104 and the support bracket 102 during telescoping. This ensures that there is no uncontrolled relative movement of the tubular shroud portion 104 and the support bracket 102. The energy absorbing band 122 may be adjusted such that it gives a predetermined energy absorption or rate of collapse.

To accommodate the connection of the energy absorbing band 122 with the tubular shield portion 104, the support bracket 102 includes a slit 130 along the bottom of the guide portion 114. The slits 130 may thus introduce a smaller clearance into the guide portion 114 of the support shelf 102. Thus, the anvil 126 is formed as part of a clamping bolt 132, which clamping bolt 132 allows fastening of two extensions 134 of the support bracket 102, which extensions 134 extend away from the tubular shield portion 104 on either side of the slit 130, respectively. Thus, the clamping bolt 132 with the nut 136 at one end may be tightened to remove any gap between the tubular shroud portion 104 and the support bracket 102 and, optionally, apply a clamping load between the tubular shroud portion 104 and the support bracket 102. In an alternative configuration, the clamping bolt 132 and anvil 126 may be separate components, if desired.

Although the energy-absorbing band 122 is described as being connected to the tubular shroud portion 104, it is also possible to provide the energy-absorbing band 122 in an alternative position in which it is connected to the support bracket 102. In this alternative, the anvil 126 would need to be attached to the tubular shroud portion 104 to maintain its function. The energy absorbing strips 122 may also be connected at the proximal end 124 and the distal end 128, and the wound anvil 126 supporting the energy absorbing strips 122 may be omitted. Subsequent deployment will provide plastic deformation without the need to provide an anvil 126. Other options are also known to those skilled in the art.

In view of the shape of the support bracket 102, in particular the guide portion 114, the support bracket 102 may be manufactured by extrusion, giving the desired constant cross-section. Simple machining may then produce the holes 120, the fixation points 108, and other details (if present). This manufacturing process allows the support bracket 102 to be produced in a more cost effective and efficient manner. For example, in the present embodiment, the only secondary processing that needs to be performed is to cut the extruded portion to a certain length and machine the six holes that are needed for the fixing point 108, the fragile pin 118, and the clamp bolt 132.

The switch mount 138 is located towards the end of the shaft 106 where a handwheel (not shown) is attached. The switch mount 138 provides a mounting point for the combined switch lever and/or key lock. The switch mount 138 is optional and need not be provided if not required.

Finally, a steering column assembly 200 according to a second embodiment of the present invention is shown in figure 5. In most respects, this embodiment is the same as that of fig. 3, including the same reference numerals, and therefore most of the description is omitted for the sake of brevity. However, the assembly 200 of the second embodiment also includes an inner column tube 242, and thus the outer column tube is slightly shortened, although this is not required. The inner cylindrical tube 242 is received within the tubular shield portion 104, and the tubular shield portion 104 may therefore be referred to as the outer cylindrical tube 104, the inner cylindrical tube 242 and the outer cylindrical tube 104 together constituting a shield. The inner column tube may thus provide more support, stability, and/or guidance to the outer column tube during telescoping of the assembly 200.

Claims

1. A retractable but non-adjustable steering column assembly for a vehicle comprising:

a support bracket for fixing to a fixed portion of a vehicle, the support bracket including an integrally formed guide portion; and

a tubular shield portion supporting the steering column shaft, the tubular shield portion being fixed relative to and at least partially within the guide portion in normal use;

wherein, in case of a collision, the tubular shield part is moved relative to the longitudinal axis of the tubular shield part by a support bracket and is axially and controlled rotationally guided relative to the longitudinal axis of the tubular shield part;

wherein the support bracket is integrally formed as one piece; and is

Wherein the guide portion of the support bracket has a geometrically similar shape, or a substantially geometrically similar shape, to the tubular shield portion, and the guide portion of the support bracket is deformable such that the guide portion is fastenable around the tubular shield portion.

2. A telescopic but non-adjustable steering column assembly according to claim 1 in which the support bracket further comprises a connecting portion for fixing to a fixed portion of a vehicle.

3. A telescopic but non-adjustable steering column assembly according to claim 1 or 2 in which the tubular shroud portion and the guide portion are in contact with one another such that, in use, a reaction force is generated between the tubular shroud portion and the guide portion, the reaction force having components in orthogonal directions in a plane perpendicular to the longitudinal axis of the tubular shroud portion.

4. A collapsible but non-adjustable steering column assembly according to claim 1 in which the tubular shroud portion has a non-circular cross-section in a plane perpendicular to the longitudinal axis of the tubular shroud portion.

5. A collapsible but non-adjustable steering column assembly according to claim 1 in which the tubular shroud portion has a polygonal cross-section in a plane perpendicular to the longitudinal axis of the tubular shroud portion.

6. A telescopic but non-adjustable steering column assembly according to claim 1 in which the guide portion includes an elongate bearing surface which extends in the axial direction of the tubular shroud portion over which the tubular shroud portion slides during a collision.

7. A retractable but non-adjustable steering column assembly according to claim 6 in which there are provided a plurality of elongate bearing surfaces which complementarily engage with corresponding elongate bearing surfaces on the tubular shroud portion.

8. A telescopic but non-adjustable steering column assembly according to claim 1 in which the support bracket is made by an extrusion process.

9. A telescopic but non-adjustable steering column assembly according to claim 1 further comprising an inner column tube receivable within the tubular shroud portion, the tubular shroud portion thus forming an outer column tube.

10. A support bracket for use in a non-adjustable steering column assembly, the support bracket comprising a connecting portion for attachment to a fixed part of a vehicle and an integrally formed guide portion for locating and guiding a corresponding tubular shroud portion,

wherein the support bracket is integrally formed as one piece; and is

Wherein the guide portion of the support bracket has a geometrically similar shape, or a substantially geometrically similar shape, to the tubular shield portion, and the guide portion of the support bracket is deformable such that the guide portion is securable around the tubular shield portion.

11. A support bracket according to claim 10, wherein the guide portion has a non-circular cross-section in a plane perpendicular to its longitudinal axis.

12. The support bracket of claim 11, wherein the non-circular cross-section is a polygonal cross-section.