Steering column arrangement

Abstract

Steering column assembly (100) with an adjustable casing (110, 120) that at least partially surrounds a steering shaft (130) and a clamping device that is operable between a clamping position in which the adjustable casing (110, 120) is locked in place and a release position in which the adjustable casing (110, 120) can be moved to adjust a length and / or inclination of the steering column assembly, wherein the clamping device comprises a clamping pin (140), a locking handle (160) and a cam assembly (200) attached to the clamping pin (140), wherein the cam assembly (200) comprises first and second cam parts (210, 230) which can be moved relative to each other by actuating the locking handle (160) to change an overall length of the cam assembly (200),wherein the release position of the cam device (200) is defined by contact of a first end stop (250) of the first cam part (210) with a second end stop (260) of the second cam part (230), characterized in that at least one of the end stops (250) has a resilient damping element (252) which provides damping and reduces noise when the at least one end stop (250) comes into contact with the other end stop (260) upon reaching the release position of the clamping device.

Description

[0001] This invention relates to improvements of steering column arrangements.

[0002] It is known to provide a steering column arrangement. The arrangement is either length-adjustable, allowing the steering wheel to be moved towards and away from the driver, or tilt-adjustable, allowing the steering wheel to be moved up and down relative to the driver. This allows for a comfortable driving position and, if present, for the optimal positioning of a steering wheel-mounted driver airbag relative to the driver's body. A steering column that is length- or tilt-adjustable is known as a simply adjustable arrangement, and one that allows adjustment of both is known as a double-adjustable arrangement.

[0003] It is important that the arrangement is easy to adjust when needed, yet remains rigidly fixed in one position while the vehicle is being driven. This is achieved by means of a steering column shroud that surrounds a steering column shaft, which supports the steering wheel. The shroud is secured in place by a releasable clamping device. When the clamping device is in the engaged position, the shroud and steering wheel are fixed relative to a vehicle part, typically the firewall. When it is in the disengaged position, the shroud can move freely relative to the firewall, allowing the steering wheel position to be adjusted.

[0004] Various clamping devices are known, but one of the most common types incorporates a clamping mechanism that can be released or locked by rotating a handle attached to a clamping pin or bolt. The handle is attached to a first part of a cam assembly, which rotates with the handle around the axis of the clamping pin or bolt. A second part of the cam assembly is prevented from rotating and interacts with the first part. Rotating the handle moves the two cam parts relative to each other, increasing or decreasing the overall length of the cam assembly depending on the direction in which the handle is turned. This change in the length of the cam assembly provides the locking function of the clamping device.

[0005] EP 1 795 425 A2 describes a steering column assembly with a clamping device. The clamping device has a fixed cam section with lateral arms and flexible tabs that constantly press a movable cam section of the clamping device against the fixed cam section to prevent play and rattling between the two cam sections.

[0006] According to a first aspect, the invention provides a steering column assembly with an adjustable casing that at least partially surrounds a steering shaft and a clamping device that is operable between a clamping position in which the adjustable casing is locked in place and a release position in which the adjustable casing can be moved to adjust the length and / or inclination of the steering column assembly, wherein the clamping device comprises a clamping pin, a locking handle and a cam assembly attached to the clamping pin, wherein the cam assembly comprises first and second cam parts that can be moved relative to each other by actuating the locking handle in order to change the overall length of the cam assembly.wherein the release position of the cam device is defined by contact of a first end stop of the first cam part with a second end stop of the second cam part, characterized in that at least one of the end stops has a resiliently compliant damping element which causes damping when the at least one end stop comes into contact with the other end stop when the release position of the clamping device is reached.

[0007] The applicant has recognized that providing a resilient damping element as part of the end stop or part of the other cam section reduces the noise that would otherwise occur when the cam reaches the fully open position.

[0008] The resilient damping element can comprise a rubber component or another element made of relatively soft material, whereas the first and second cam sections can comprise sintered metal components. It can be detachable from the rest of the end stop or integrally formed with it, for example, by injection molding in place. In some arrangements, it is even possible for the entire end stop to be a resilient damping element. Here, "element" refers to a single part or an assembly of parts.

[0009] The first end stop can preferably be a projection on the first cam section, and the damping element can be an O-ring mounted on the projection. It can be a simple sliding fit on the projection. The end stop can have a groove to help secure the O-ring. The second end stop can be a surface on the second cam section. The first cam section is preferably made of sintered metal, and the projection is preferably an integral part of the sintered metal cam section.

[0010] Using an O-ring on a projection is a simple and inexpensive solution because O-rings are readily available and because it can be easily replaced if necessary, for example, if it wears out over time.

[0011] The second cam part can be a movable cam part that rotates with the clamping pin when the handle is operated, and the first cam part can comprise a fixed cam part that is held in place so that it cannot rotate.

[0012] One of the cam parts may have a cam and the other of the cam parts may have a cam follower that moves over the cam as the handle rotates to change the length of the cam assembly.

[0013] Only one embodiment of the present invention, as illustrated in the accompanying drawings, will now be described by way of example, in which: Fig. 1 a cross-sectional view of part of an embodiment of a steering column assembly, Fig. 2 a spatial representation of the stationary cam part of the arrangement Fig. 1 before installation is, Fig. 3 a spatial representation of the arrangement in use in full clamping position, Fig. 4 a spatial representation of the arrangement in use in a completely unclamped state, and Fig. 5 a split view of a detail of the stationary cam part from Fig. 3 is the one that shows the first end stop.

[0014] As in Fig. Figure 1 shows a steering column assembly 100 comprising an adjustable shroud, which, as shown, has a fixed shroud section 110 and a movable shroud section 120 surrounding a steering shaft 130. The movable shroud section 120 fits telescopically around the fixed section 110. One end of the shaft 130 carries a steering wheel (not shown), and the other end is connected to the vehicle's wheels by means of a steering mechanism (also not shown). This mechanism may include an electric servo-assist motor. A clamping device connects the fixed shroud section 110 to the movable shroud section 120. It includes a clamping pin 140 that passes through spaced-apart openings in the fixed section and the movable section. A nut 150 is provided on one end of the pin, and a locking handle 160 is provided on the other.The handle is held by an adjustable nut 190, which is screwed onto the end of the clamping pin 140. The handle has a grip dimensioned to allow it to be comfortably grasped by the vehicle's driver. A cam device 200 is arranged on the pin between the locking handle 160 and the movable sheathing part 120 and is dimensioned such that it does not fit through the opening in the movable sheathing part 120. The pin 140 also passes through openings in two spaced-apart arms 170, 175 of a clamping bracket that is attached to the vehicle's front wall (not shown).

[0015] As will be evident, the locking handle 160 can be rotated to clamp and release the clamping device, and this changes the overall length of the cam assembly 200. At its maximum length, the clamping device is in a clamped position, and the movable and fixed casing parts are pressed together so that they cannot move. At its shortest length, the casing parts are separated and free to move, limited by the dimensions of the opening in the movable casing part. As shown, the opening 180 is elongated along the axis of the steering shaft, so that the overall length of the steering column assembly is adjustable.

[0016] The cam assembly has a fixed cam part 210 made of sintered metal, which is held against rotation by an engagement with the arm 170 of the clamping carrier. The fixed cam part is best made of Fig. 2 and Fig. As shown in Figure 5 of the drawings, the clamping pin 140 passes through a hole 220 in the center of the stationary cam section. The cam assembly also includes a movable cam section 230, also made of sintered metal, which is likewise attached to the clamping pin 140. This movable cam section is fixed so that it rotates with the handle by being attached to the clamping pin, thus allowing the clamping pin 140 to rotate with the handle 160. The stationary cam section 210 has a cam surface 240 that faces and engages with a cam follower formed on the movable cam section. When the movable section rotates relative to the stationary cam section 210, the cam follower moves across the cam surface, causing the overall width of the cam assembly to change (measured in a direction parallel to the axis of the clamping pin).As shown, in reality there are four cam surfaces 240 arranged at equal distances from each other on the stationary part and four cam followers arranged at equal distances from each other on the second cam part 230.

[0017] During operation, the driver can use the handle to lock and unlock the steering column assembly. As in Fig. Figure 3 shows the operator turning the handle 160 to move the clamping device from the released to the locked position. As it reaches the fully locked position, it becomes increasingly difficult to turn because the cam assembly, the clamping support arms, and the movable and fixed sheathing parts between the nut 150 and the cam assembly 200 are pressed together. Conversely, when the handle 160 is turned to move the assembly from the locked to the released position, it is easier to turn. This often results in the handle 160 being moved into the fully released position at high speed.

[0018] To define the fully solved position, which in Fig. As shown in Figure 4, the stationary cam part 210 is provided with a first end stop 250, and the movable cam part is provided with a second end stop 260. The two end stops 250 and 260 come into contact with each other when the release position is reached and prevent any further rotation of the locking handle in this release direction. The first end stop 250 has a projection 251 and a resilient damping element 252, which includes an O-ring that is securely fixed in a groove 253 around the projection 251. This is shown in Figure 4. Fig. As can be seen in drawing 5. This soft component touches the second end stop.

[0019] The provision of the soft O-ring 252 results in damping when the clamping device quickly reaches the fully released position, which considerably reduces any noise that would otherwise occur when the first end stop 250 strikes against the second end stop 260.

[0020] A person skilled in the art will recognize that various modifications are possible within the scope of the invention, particularly with regard to the design of the clamping device. The clamping device can be designed such that an increase in the overall length of the cam assembly releases the arrangement rather than clamping it, and the manner in which the clamping is achieved can be varied. Furthermore, although the resilient damping element is shown as an O-ring forming part of the stationary cam section, it can also be part of the movable cam section. In some embodiments, it can also be molded into the end stop, or the entire end stop can be a resilient damping element.

Claims

[1] Steering column assembly (100) with an adjustable casing (110, 120) that at least partially surrounds a steering shaft (130) and a clamping device that is operable between a clamping position in which the adjustable casing (110, 120) is locked in place and a release position in which the adjustable casing (110, 120) can be moved to adjust a length and / or inclination of the steering column assembly, wherein the clamping device comprises a clamping pin (140), a locking handle (160) and a cam assembly (200) attached to the clamping pin (140), wherein the cam assembly (200) comprises first and second cam parts (210, 230) which can be moved relative to each other by actuating the locking handle (160) to change an overall length of the cam assembly (200),wherein the release position of the cam device (200) is defined by a contact of a first end stop (250) of the first cam part (210) with a second end stop (260) of the second cam part (230), characterized by , that at least one of the end stops (250) has a resilient damping element (252) which provides damping and reduces noise when at least one end stop (250) comes into contact with the other end stop (260) when the clamping device reaches the release position. [2] Steering column arrangement (100) according to claim 1, wherein the resilient damping element (252) comprises a rubber component (252). [3] Steering column arrangement (100) according to claim 1 or claim 2, wherein the first end stop (250) is a projection (251) of the first cam part (210). [4] Steering column assembly (100) according to claim 3, wherein the damping element (252) has an O-ring (252) which is mounted on the projection (251). [5] Steering column assembly (100) according to claim 3, which has a groove (253) on the end stop (250) which secures the damping element (252). [6] Steering column arrangement (100) according to one of the preceding claims, wherein the second cam part (230) comprises a movable cam part (230) which rotates with the clamping pin (140) when the locking handle (160) is actuated, and wherein the first cam part (160) comprises a fixed cam part (160) which is held in place so that it cannot rotate. [7] Steering column assembly (100) according to one of the preceding claims, wherein one of the cam parts (210) has a cam and the other of the cam parts (230) has a cam follower which moves over the cam when the locking handle (160) rotates to change the length of the cam assembly (200).

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