Motor-driven position adjustment apparatus for steering wheel

• US 7,410,190 B2
• Filed: 02/17/2006
• Issued: 08/12/2008
• Est. Priority Date: 02/17/2005
• Status: Expired due to Fees

• Current Assignee: NSK Limited
• Original Assignee: NSK Limited
• Inventors: Sawada, Naoki, Iwakawa, Masato, Fujiwara, Takeshi, Shoda, Akihiro
• Primary Examiner(s): To; Toan C
• Application Number:
  US11/363,295
• Publication Number:
  US 20060191368A1
• Time in Patent Office: 907 Days
• Field of Search: 280/775, 280/777, 280/779, 744/92, 744/93, 180/400, 180/427, 180/428, 180/434, 180/444
• US Class Current: 280/777
• CPC Class Codes: B62D 1/181 with power actuated adjustment, e.g. with position memory
• CPC Class Codes: B62D 1/19 incorporating energy-absorbing arrangements, e.g. by being yieldable or collapsible shock absorbers using plastic deformation of members in general F16F7/12

Abstract

In a motor-driven steering wheel position adjustment apparatus, a nut 17 being a driven member is mounted such that it can be detached from an inner column of a steering column, based on a shock load applied at the time of a secondary collision, and therefore a threaded rod of a feed screw mechanism does not have resistance with respect to displacement of the inner column in the forward direction at that time. Improvement in the protection of a driver at the time of a collision can thus be achieved, and, since an integrated member can be used for the threaded rod, silence during the position adjustment of a steering wheel by the feed screw mechanism can be ensured.

Claims

1. A motor-driven position adjustment apparatus for a steering wheel comprising:

a steering column with a steering shaft rotatably supported inside;

a driven member joined to a part of the steering column;

a push-pull rod which is arranged in the axial direction of the steering column in a state where one end is joined to the driven member;

a driving member that is rotatably supported on the periphery of a part toward the other end of the push-pull rod, and that displaces the push-pull rod in the axial direction of the steering column as it rotates; and

an electric motor for rotating and driving the driving member, and the steering column being displaced based on a relative displacement of the driving member and the push-pull rod based on a current supplied to the electric motor to adjust a position of a steering wheel supported on an end of the steering shaft,

wherein at least either one of a joined part between the push-pull rod and the driven member, and a joined part between the driven member and the steering column, can be separated based on a shock load applied at the time of a collision, and

wherein the separable joined part includes a pair of members to be joined, which are fitted via an elastic deformable spacer.

2. A motor-driven position adjustment apparatus for a steering wheel according to claim 1, wherein the spacer has a high coefficient of friction.

3. A motor-driven position adjustment apparatus for a steering wheel according to claim 1, wherein a spacer is interposed between an outer peripheral surface of the push-pull rod, and an inner peripheral surface of a retainer sleeve arranged on the periphery of the push-pull rod, and the retainer sleeve is joined to a driven member such that it can be displaced freely together with the driven member at the time of a collision.

4. A motor-driven position adjustment apparatus for a steering wheel according to claim 1, wherein an outer diameter of a part of the push-pull rod that is positioned on an inner diameter side of the spacer at a normal time, is made larger than an outer diameter of a part of the same that enters the inner diameter side of the spacer when a collision occurs.

5. A motor-driven position adjustment apparatus for a steering wheel according to claim 4, wherein the push-pull rod has a first part and a second part of smaller outer diameter than the first part, two spacers whose inner diameters are different in a free state are provided at two positions in the axial direction on the periphery of the push-pull rod, and at normal times, the first part of the push-pull rod is located inside of the spacer whose inner diameter is larger in the free state, and the second part of the push-pull rod is located inside of the spacer whose inner diameter is small in the free state.

6. A motor-driven position adjustment apparatus for a steering wheel according to claim 1, wherein the separable joined part is constructed by joining a pair of members to be joined, using a joining member that breaks based on a shock load.

7. A motor-driven position adjustment apparatus for a steering wheel according to claim 1, wherein the spacer comprises a metallic spring.

8. A motor-driven position adjustment apparatus for a steering wheel according to claim 1, wherein the spacer comprises a non-metallic elastic material.