TILT STEERING APPARATUS

• US 20140284909A1
• Filed: 07/10/2013
• Published: 09/25/2014
• Est. Priority Date: 07/12/2012
• Status: Active Grant

• Current Assignee: NSK Limited
• Original Assignee: NSK Limited
• Inventors: Nakazato, Youhei, Yamamoto, Kou, Narita, Noritomo
• Granted Patent: US 9,150,241 B2
• Time in Patent Office: Days
• US Class Current: 280/775
• CPC Class Codes: B62D 1/184 Mechanisms for locking columns at selected positions
• CPC Class Codes: B62D 1/187 with tilt adjustment; with tilt and axial adjustment B62D1/183, B62D1/19 takes precedence

Abstract

Construction of a tilt steering apparatus is provided that is capable of preventing the occurrence of unpleasant noise during height adjustment of a steering wheel 1, and maintains sufficient durability and smooth operation. The tilt steering apparatus of the present invention is provided with stoppers 65 in at least two locations in a buffer member 21 c that are rotationally symmetric about the center axis of an adjustment rod 14, and that when a driven-side cam 15b is rotated as the axial dimension of a cam apparatus 47 is expanded or contracted, controls rotation of the driven-side cam 15b so that a convex engaging portion 39c does not collide with the front-side edge or rear-side edge of a vertically long hole 35b.

Claims

1. A tilt steering apparatus, comprising:

a steering column that is pivotally displaced centered around a tilt shat that is provided in a width direction of a section on a front side thereof, and supports a steering shaft on an inside thereof such that the steering shaft can rotate freely;

a fixed-side bracket made of a metal material that is supported by a vehicle body and comprises a pair of support plate portions that hold the steering column;

vertically long holes of the steering column that are provided in positions in each of the pair of support plate portions that are aligned with each other, and that extend in the up-down direction of the steering column;

an adjustment rod that is inserted through the vertically long holes in the width direction of the steering column;

an anchor portion on a base-end portion of the adjustment rod and that engages with one of the vertically long holes that is provided in one of the pair of support plate portions so as to be able to be displaced along the one vertically long hole;

a driven-side cam made of a metal material that constitutes a cam apparatus that expands or contracts an axial dimension thereof according to rotation of the adjustment rod, that is fitted around a portion near a tip end of the adjustment rod so as to be capable of relative rotation with respect to the adjustment rod, that comprises a driven-side cam surface formed on an outside surface thereof, and a convex engaging portion formed so as to protrude from an inside surface thereof and engaging with other of the vertically long holes that is provided in other of the pair of support plate portions so as to be able to be displaced along the other vertically long hole in a state such that rotation thereof centered around the adjustment rod is suppressed; and

a buffer member that is formed using a material that is softer than the metal material of the driven-side cam and the metal material of the fixed-side bracket, and that is attached to the convex engaging portion;

stoppers being provided in at least two locations in the buffer member that are rotationally symmetric about a center axis of the adjustment rod, and the stoppers preventing collision between the convex engaging portion and a front-side edge or a rear-side edge of the other vertically long hole when the driven-side cam rotates as the axial dimension of the cam apparatus expands or contracts, and regulate the rotation of the driven-side cam.

2. The tilt steering apparatus according to claim 1, wherein

the buffer member comprises a pair of buffer portions that have shapes to cover surfaces on both top and bottom ends of the convex engaging portion, and crank-shaped stepped surfaces that match each other are formed on the surfaces of both the top and bottom ends of the convex engaging portion and on end surfaces of the pair of buffer portions that face each other so as to match each other, and the stepped surfaces of the pair of buffer portions function as the stoppers.

3. The tilt steering apparatus according to claim 2, wherein

buffer-portion-side protrusions that protrude in the up-down direction are respectively provided in part in a forward-backward direction of the end surfaces of the pair of buffer portions that face each other, and convex-portion-side protrusions that protrude in the up-down direction are respectively provided in part in the forward-backward direction of the surfaces on both the top and bottom ends of the convex engaging portion, and the buffer-portion-side protrusions that come in contact with the convex-portion-side protrusions function as the stoppers.

4. The tilt steering apparatus according to claim 3, wherein

the cam apparatus further comprises a drive-side cam fastened around a tip-end portion of the adjustment rod so as to be able to rotate centered around the adjustment rod and having a drive-side cam surface that is provided on an inside surface thereof so as to come in contact with the driven-side cam surface;

and the convex engaging portion and the buffer member are constructed such that side surfaces of the convex-portion-side protrusions on a front side in a tightening direction of the drive-side cam, which is a rotational direction of the drive-side cam when the axial dimension of the cam apparatus is expanded, come in contact with side surfaces of the buffer-portion-side protrusions on a rear side in the tightening direction.

5. The tilt steering apparatus according to claim 3, wherein a width dimension in the forward-backward direction of the buffer-portion-side protrusions is one second or greater than a width dimension in the forward-backward direction of the end surfaces of the pair of buffer portions that face each other.

6. The tilt steering apparatus according to claim 3, wherein the surfaces on both the top and bottom ends of the convex engaging portion and the end surfaces of the pair of buffer portions that face each other are rotationally symmetric about the center axis of the adjustment rod.

7. The tilt steering apparatus according to claim 1, wherein

the cam apparatus further comprises a drive-side cam fastened around a tip-end portion of the adjustment rod so as to be able to rotate centered around the adjustment rod and having a drive-side cam surface that is provided on an inside surface thereof so as to come in contact with the driven-side cam surface;

and cover portions that cover portions near both the top and bottom ends of at least side surfaces on a front side of both side surfaces of the convex engaging portion in a tightening direction of the drive cam, which is a rotational direction of the drive-side cam when the axial dimension of the cam apparatus is expanded, prevent abutment between the portions near both the top and bottom ends of the side surfaces on the front side and inside edges on the front side of the vertically long hole, and functions as the stoppers, are provided in part of the buffer member.

8. The tilt steering apparatus according to claim 7, wherein

the buffer member comprises a pair of buffer portions that cover the surfaces on both the top and bottom ends of the convex engaging portion;

and the cover portions extend in the up-down direction from at least end portions on the front-side in the tightening direction of the pair of buffer portions.

9. The tilt steering apparatus according to claim 8, wherein

concave portions are formed on both the top and bottom ends of surfaces on both front and rear sides of the convex engaging portion;

a width dimension in the forward-backward direction of the both the top and bottom end portions of the convex engaging portion is narrower than a width dimension in eth forward-backward direction of an intermediate portion in the up-down direction of the convex engaging portion;

the cover portions extend in directions toward each other from both front and rear end portions of the pair of buffer portions, and engage with the concave portions; and

both side surfaces in the forward-backward direction of the intermediate portion in the up-down direction of the convex engaging portion do not protrude further in the forward-backward direction than the cover portions.

10. The tilt steering apparatus according to claim 1, wherein

the buffer member comprises a pair of buffer portions that have shapes to cover the surfaces on both the top and bottom ends of the convex engaging portion, and that respectively have low-rigidity portions that are formed by portions of which material has been removed and are formed in both the front and rear portions thereof.

11. The tilt steering apparatus according to claim 10, wherein

the low-rigidity portions protrude further in the forward-backward direction than the surfaces on both the front and rear sides of the convex engaging portion, and in a neutral state in which no rotation force in a direction that expands the axial dimension of the cam apparatus is applied, only the low-rigidity portions come in elastic contact with edges on both front and rear sides of the vertically long hole.

12. The tilt steering apparatus according to claim 1, wherein a through hole having an elliptical shape as seen from the axial direction is provided so as to pass in the axial direction through a center portion of the driven-side cam, and a pair of hook-shaped pieces are provided so as to protrude from both end portions in a width direction of the center portion in the up-down direction of the outside surface of the buffer member such that tip-end portions of the hook-shaped pieces are locked to edge portions on both sides in a major axis direction of the through hole.

13. The tilt steering apparatus according to claim 1, further comprising:

a receiving bracket that is fastened to the outside surface of the other support plate portion and that comprises a concave groove that is provided with a female gear on an inside surface thereof, and extends in a direction along the vertically long hole of the other support plate portion, and is opened toward the front or the rear;

a pivot arm that comprises a male gear on one end portion thereof that can engage with or disengage from the female gear, and is supported by part of the outside surface of the other support plate portion so as to be able to be pivotally displaced centered around the adjustment rod; and

a pivot transmission portion that is provided between the pivot arm and the adjustment lever, and that in a state that the axial dimension of the cam apparatus is expanded by rotating the adjustment lever, causes the female gear to engage with the male gear, and that in a state that the axial dimension of the cam apparatus is contracted, causes the pivot arm to pivot in a direction to cause the female gear and male gear to disengage from each other.