JP3532122B2 - Electric steering column - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric steered steering column, and more particularly to an electric steered mechanism capable of absorbing relative movement of a worm wheel of an electric steered mechanism in an axial direction, an axis-perpendicular direction and a tilt. Is.

[0002]

2. Description of the Related Art An electric steered steering column is a part of a system that enables automatic steering of a vehicle. The steering column enables automatic driving without being steered by a driver. The rotation torque generated by the forward and reverse rotations of the electric motor is transmitted to the steering gear box via the worm wheel. Conventionally, in this electric steered steering column, the worm wheel is directly fitted to the steering shaft.

[0003]

However, in the conventional electric steered steering column in which the worm wheel is directly fitted to the steering shaft, the parallelism between the steering shaft and the jacket tube is deviated at the manufacturing stage or the like. Alternatively, when the jacket tube and the housing are displaced from each other by a right angle, the rotational friction is abnormally increased due to the twisting of the housing and the worm wheel. Further, since the worm wheel directly attached to the steering shaft is fixed to the worm wheel attached to the output shaft of the electric motor, the assembly manufacturing process is complicated.

Therefore, the present invention is intended to solve the above-mentioned inconvenience in the electric steered steering column.

[0005]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, a hollow shaft fitted to a steering shaft is formed with an engaging projection in an axial direction on an outer peripheral surface thereof, and the hollow shaft is formed. A worm wheel having an engaging recess formed in the shaft hole in the axial direction is loosely inserted into the shaft, and conical chamfers are formed at both ends of the shaft hole of the worm wheel, and the chamfer and the hollow shaft are separated from each other. Provided is an electric steered steering column in which a ring-shaped body made of an elastic body is compressively interposed therebetween.

According to a second aspect of the present invention, the hollow shaft has a flange portion at one end and a threaded portion at the other end so that a nut can be screwed into the threaded portion. An electric steered steering column as described is provided.

Further, according to a third aspect of the present invention, the hollow shaft has a flange portion at one end and a threaded portion at the other end, and a nut is screwed into the threaded portion. The electric steered steering column according to claim 1, wherein the annular body can be compressed by pressing it toward the flange portion.

Therefore, since the hollow shaft and the worm wheel are connected through serrations or splines, and the annular body made of an elastic material is arranged at both ends of the shaft hole of the worm wheel via the chamfered portion so as to be compressible. The annular body made of an elastic body can absorb or restore the deviation of the parallelism between the steering shaft and the jacket tube or the deviation of the perpendicularity between the jacket tube and the housing.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 to 4, a housing 3 is orthogonally fixed to an end portion of a jacket tube 2 of a tilt telescopic steering column 1, and a worm wheel rotatably mounted in the housing 3 via bearings 4 and 4. 5, the engagement recess 6 made of spline or serration is formed on the inner peripheral surface of the shaft hole of the worm wheel 5.
Are formed. The housing 3 has molded plates 3c and 3d fixed to the end plates 3a and 3b, into which the jacket tube 2 is fitted, in a container-lid relationship, and these are fastened with a plurality of bolts 3e.

A shaft 8 with a flange, in which an engaging protrusion 7 made of a spline or serration that meshes with the engaging recess 6 is formed, is fitted on a steering shaft 9. As shown in FIG. 5, the engagement concave portion 6 and the engagement convex portion 7 are loosely fitted to each other so that a gap C can be formed around the teeth of the spline or the teeth of the session.
It is planned that the parallelism between the axis of the worm wheel 5 and the axis of the flanged shaft 8 will change.

The flanged shaft 8 has a flange portion 8a formed at one end and a threaded portion 8b formed at the other end, and a serration 10 is formed on the inner surface of the hollow.
The flanged shaft 8 and the steering shaft 9 are coupled so as to be able to transmit torque by engaging with serrations 11 engraved on the outer peripheral surface thereof. Therefore, the rotational torque of the worm wheel 5 is transmitted to the steering shaft 9 via the shaft with flange 8. The flanged shaft 8 and the steering shaft 9 are also coupled in the axial direction as follows. That is, the flanged shaft 8 is provided with a through hole 8c extending from the outer peripheral surface side toward the shaft center, and correspondingly, an annular groove 9a is provided on the outer periphery of the steering shaft 9. And these through holes 8c and the annular groove 9
The space defined by a is filled with thermoplastic.

Conical chamfers 12, 12 are formed at both ends of the shaft hole of the worm wheel 5, and a space formed by the chamfer 12, the flanged shaft 8 and the flange 8a, and the space facing each other. Chamfer 1 on the side
2 and the flanged shaft 8 and the collar 14, the annular portion 13 made of an elastic body such as rubber,
13 is interposed, and the annular bodies 13, 13 are compressed and deformed by the collar 14 tightened by the flange portion 8a and the nut 15 and are in pressure contact with the chamfered portions 12, 12. Therefore, the rotation torque of the worm wheel 5 to be transmitted by the engagement concave portion 6 and the engagement convex portion 7 can be transmitted, and
When the parallelism of the axes of the worm wheel 5 and the flanged shaft 8 changes, the annular body 13 elastically deforms to absorb the play.

As shown in FIGS. 2 and 3, the electric motor 16 is fixed to the housing 3 in a direction orthogonal to the steering column 1. Although not shown, the worm fixed to the output shaft is a worm. It meshes with the wheel 5. The steering shaft 9 has a lower end on the steering gear box side connected with a universal joint 20 of an intermediate shaft (not shown), and an upper end on the driver's side connected with a tube 21, which is spline-engaged with the tube 21. The lower end of the upper shaft 22 is inserted so as to be movable in the axial direction, and the universal joint 2 is attached to the upper end of the upper shaft 22.
A shaft 24 that pivotally mounts a steering wheel (not shown) is connected via 3.

An upper bracket 25 for suspending and supporting the steering column on the vehicle body is provided on the upper end of the jacket tube 2.
The telescopic housing 26 has a nut 27, and a screw shaft 28 rotated by an electric motor fixed to the jacket tube 2 is screwed into the nut 27 so that the telescopic housing 26 can move forward and backward in the axial direction.

The tilt housing 28 that supports the shaft 24 has its lower end tiltably connected to the upper end of the telescopic housing 26, and the nut 3 that is screwed into a screw shaft 31 that rotates electrically.
0 is set.

Thus, the worm wheel 5 is joined to the hollow shaft 8 fitted on the steering shaft 9 through serrations or splines, and chamfered portions 12 are formed at both ends of the shaft hole of the worm wheel 5 to form an elastic body. Since the ring-shaped body 13 is formed to be compressible, the engaging portions 6 and 7 formed of serrations or splines are formed.
And the worm wheel 5 with the annular body 13 made of an elastic body.
Can move relative to the hollow shaft 8 in the axial direction, the direction perpendicular to the axis, and the inclination.

[0017]

As described above, according to the present invention, the worm wheel is moved relative to the hollow shaft in the axial direction, the axis-perpendicular direction, and the inclination by the annular body including the engaging convex portion, the engaging concave portion, and the elastic body. Since it is possible to absorb the inclination of the steering shaft with respect to the worm wheel,
Smooth rotation can be obtained. Further, it is possible to prevent abnormal noise from being generated during relative movement of the worm wheel and the steering shaft in the axial direction, the axis-perpendicular direction, and the inclination. Further, since the compressed annular body always urges the worm wheel in the direction away from the hollow shaft, the rattling due to the gap between the two is not transmitted to the steering shaft as a rattling sensation. In addition, since the worm wheel can move relative to the hollow shaft in the axial direction, the axis-perpendicular direction, and the inclination, the annular body made of an elastic body improves the assembling property when the electric motor is unitized.

[Brief description of drawings]

FIG. 1 is a partial sectional side view of an electric steered steering column showing an embodiment of the present invention.

FIG. 2 is a plan view of an electric steering section.

FIG. 3 is a rear view of the electric steering section.

FIG. 4 is an enlarged cross-sectional view of an electric steering section.

5 is an enlarged sectional view taken along line AA of FIG.

[Explanation of symbols]

1. Tilt telescopic steering column 2 ... Jacket tube 3 ... Housing 5 ... Worm wheel 6 ... Engagement recess 7 ... Engaging protrusion 8 ... Flanged shaft 8a ... Flange part 8b ... screw part 9 ... Steering shaft 10, 11 ... Serration 12 ... Chamfer 13 ... Ring body 14 ... Color 15 ... Nut 16 ... Electric motor

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-11-48995 (JP, A) JP-A-6-193642 (JP, A) JP-A-11-29052 (JP, A) Actual development Sho-51- 33637 (JP, U) Actual development Sho 63-139353 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B62D 5/04 F16D 1/06 F16H 57/02

Claims (3)

(57) [Claims] 1. A worm wheel having an engaging protrusion formed in the axial direction on an outer peripheral surface of a hollow shaft fitted to a steering shaft, and an engaging recess formed in the axial hole in the hollow shaft. A conical chamfer is formed at both ends of the shaft hole of the worm wheel, and an annular body made of an elastic body is compressibly interposed between the chamfer and the hollow shaft. An electric steering steering column. 2. The electric steering steering column according to claim 1, wherein the hollow shaft has a flange portion at one end and a threaded portion at the other end so that a nut can be screwed into the threaded portion. 3. The hollow shaft has a flange portion at one end and a threaded portion at the other end, and a nut is screwed into the threaded portion, and the collar presses the collar toward the flanged portion. The electric steered steering column according to claim 1, wherein the annular body can be compressed.