Telescopic rotation transmission shaft and method for producing same

Patent metadata

Field	Value
Publication number	US-10717459-B2
Application number	US-201615743012-A
Country	US
Kind code	B2
Filing date	Jul 26, 2016
Priority date	Jul 27, 2015
Publication date	Jul 21, 2020
Grant date	Jul 21, 2020

Abstract

A portion of the target guide plate interposed between the rolling surface of each ball and an inner surface of the sub-concave groove is supported at the other radial surface opposite to the rolling surface of each ball by the inner surface of the sub-concave groove at a state where one radial surface facing towards the rolling surface of each ball is pressed by the rolling surface of each ball and is thus curved along the rolling surface of each ball.

First claim

The invention claimed is:

1. An extensible rotation transmission shaft comprising:
an inner shaft formed with an axial inner-side concave groove at at least one place of an outer peripheral surface thereof in a circumferential direction;
an outer shaft formed with an axial outer-side concave groove at at least one place of an inner peripheral surface thereof in a circumferential direction, at which it is aligned with the inner-side concave groove;
a plurality of balls arranged axially side by side between the inner-side concave groove and the outer-side concave groove; and
a guide plate interposed between a rolling surface of each ball and an inner surface of the inner-side concave groove and/or between the rolling surface of each ball and an inner surface of the outer-side concave groove,
wherein one radial surface, which is positioned at the rolling surface-side of each ball, of a target guide plate, which is at least one guide plate of the guide plates, and the rolling surface of each ball are contacted only at two contact portions spaced in the circumferential direction with a central portion in the circumferential direction being interposed therebetween,
wherein the inner surface of the inner-side concave groove or the outer-side concave groove, which faces the other radial surface of the target guide plate positioned at a side opposite to the rolling surface of each ball, is formed with a sub-concave groove at at least one place of two places in the circumferential direction of which phases in the circumferential direction coincide with the two contact portions, and,
wherein a portion of the target guide plate interposed between the rolling surface of each ball and an inner surface of the sub-concave groove is supported at the other radial surface opposite to the rolling surface of each ball by the inner surface of the sub-concave groove at a state where one radial surface facing towards the rolling surface of each ball is pressed by the rolling surface of each ball and is thus curved along the rolling surface of each ball.

2. The extensible rotation transmission shaft according to claim 1 ,
wherein a sectional shape of the inner surface of the sub-concave groove is formed into a circular arc shape, and
wherein a radius of curvature of the circular arc-shaped section is greater than a sum of a radius of curvature of the rolling surface of each ball and a plate thickness of the portion of the target guide plate interposed between the rolling surface of each ball and the inner surface of the sub-concave groove.

3. The extensible rotation transmission shaft according to claim 1 ,
wherein each ball is applied with preload by plastically deforming an inner surface of at least one concave groove of the inner-side concave groove and the outer-side concave groove in a radial direction.

4. A method of manufacturing the extensible rotation transmission shaft according to claim 1 ,
wherein a portion of the target guide plate interposed between the rolling surface of each ball and the inner surface of the sub-concave groove is formed into a shape where the other radial surface opposite to the rolling surface of each ball is not contacted to the inner surface of the sub-concave groove at a state before assembling the extensible rotation transmission shaft, and is curved until the other radial surface opposite to the rolling surface of each ball is contacted to the inner surface of the sub-concave groove by pressing one radial surface facing towards the rolling surface of each ball by the rolling surface of each ball when assembling the extensible rotation transmission shaft.

5. A method of manufacturing the extensible rotation transmission shaft according to claim 1 ,
wherein the sub-concave groove is formed by pressing an inner surface of the concave groove, which faces the other radial surface of the target guide plate, of the inner-side concave groove or the outer-side concave groove by the rolling surface of each ball via the portion of the target guide plate interposed between the inner surface of the concave groove and the rolling surface of each ball and plastically deforming the inner surface of the concave groove.

6. The method of manufacturing the extensible rotation transmission shaft according to claim 5 ,
wherein the sub-concave groove is formed to be axially continuous by relatively displacing the outer shaft and the inner shaft in the axial direction.

7. The method of manufacturing the extensible rotation transmission shaft according to claim 5 ,
wherein the sub-concave groove is formed by transmitting torque between the inner shaft and the outer shaft at a state where the inner shaft being is inserted into the outer shaft.

8. The method of manufacturing the extensible rotation transmission shaft according to claim 5 ,
wherein the sub-concave groove is formed by relatively displacing the inner shaft and the outer shaft so that central axes of the inner shaft and the outer shaft are mismatched at a state where the inner shaft is inserted into the outer shaft.

9. The method of manufacturing the extensible rotation transmission shaft according to claim 5 ,
wherein the sub-concave groove is formed before the extensible rotation transmission shaft is mounted to a vehicle.

10. The method of manufacturing the extensible rotation transmission shaft according to claim 5 ,
wherein the sub-concave groove is formed after the extensible rotation transmission shaft is mounted to a vehicle.

11. The method of manufacturing the extensible rotation transmission shaft according to claim 5 ,
wherein hardness of the shaft, which is formed with the sub-concave groove, of the inner shaft or the outer shaft is lower than hardness of each ball and hardness of the target guide plate.

12. The method of manufacturing the extensible rotation transmission shaft according to claim 5 ,
wherein an inner-side guide plate, which is interposed between the rolling surface of each ball and the inner surface of the inner-side concave groove, and an outer-side guide plate, which is interposed between the rolling surface of each ball and the inner surface of the outer-side concave groove, are respectively configured as the target guide plate, and
wherein the sub-concave groove is respectively formed on the inner surface of the inner-side concave groove and the inner surface of the outer-side concave groove.

13. The method of manufacturing the extensible rotation transmission shaft according to claim 5 ,
wherein the inner-side guide plate interposed between the rolling surface of each ball and the inner surface of the inner-side concave groove is configured as the target guide plate, and
wherein the sub-concave groove is formed only on the inner surface of the inner-side concave groove.

14. The method of manufacturing the extensible rotation transmission shaft according to claim 5 ,
wherein the outer-side guide plate interposed between the rolling surface of each ball and the inner surface of the outer-side concave groove is configured as the target guide plate, and
wherein the sub-concave groove is formed only on the inner surface of the outer-side concave groove.

Assignees

• Nsk Ltd

Inventors

• Kurokawa Yoshifumi

Classifications

• F16C3/035

  with built-in bearings · CPC title

• B62D1/20 Primary

  Connecting steering column to steering gear · CPC title

• F16D3/065

  by means of rolling elements · CPC title

• F16D2300/12

  Mounting or assembling · CPC title

• F16C2326/24

  Steering systems, e.g. steering rods or columns · CPC title