Torque transmission joint and worm reduction gear

Patent metadata

Field	Value
Publication number	US-10408271-B2
Application number	US-201615564473-A
Country	US
Kind code	B2
Filing date	Apr 15, 2016
Priority date	Apr 22, 2015
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

At a state where central axes of the drive shaft and the driven shaft are matched, the drive-side concave-convex portion is engaged with a half portion on the other axial side of the coupling-side concave-convex portion with a drive-side gap of which a circumferential width size increases towards the other axial side being interposed between a circumferential side surface of each drive-side convex portion and a circumferential side surface of each coupling-side convex portion. At the state where the central axes of the drive shaft and the driven shaft are matched, the driven-side concave-convex portion is engaged with a half portion on one axial side of the coupling-side concave-convex portion with a driven-side gap of which a circumferential width size increases towards one axial side being interposed between a circumferential side surface of each driven-side convex portion and a circumferential side surface of each coupling-side convex portion.

First claim

The invention claimed is:

1. A torque-transmission joint configured to transmit torque between one axial end portion of a drive shaft and the other axial end portion of a driven shaft arranged in series with each other in an axial direction, the torque-transmission joint comprising:
a coupling provided on one circumferential surface of inner and outer circumferential surfaces with a coupling-side concave-convex portion having coupling-side convex portions arranged at a plurality of circumferential places and protruding in a radial direction;
a drive-side transmission part provided at one axial end portion of the drive shaft and provided on one circumferential surface, which faces the coupling-side concave-convex portion, of inner and outer circumferential surfaces with a drive-side concave-convex portion having drive-side convex portions arranged at a plurality of circumferential places and protruding in a radial direction; and
a driven-side transmission part is provided at the other axial end portion of the driven shaft and provided on one circumferential surface, which faces the coupling-side concave-convex portion, of inner and outer circumferential surfaces with a driven-side concave-convex portion having driven-side convex portions arranged at a plurality of circumferential places and protruding in a radial direction;
wherein at a state where central axes of the drive shaft and the driven shaft are matched, the drive-side concave-convex portion is engaged with a half portion on the other axial side of the coupling-side concave-convex portion with a drive-side gap of which a circumferential width size increases towards the other axial side being interposed between a circumferential side surface of each drive-side convex portion and a circumferential side surface of each coupling-side convex portion and
wherein at the state where the central axes of the drive shaft and the driven shaft are matched, the driven-side concave-convex portion is engaged with a half portion on one axial side of the coupling-side concave-convex portion with a driven-side gap of which a circumferential width size increases towards one axial side being interposed between a circumferential side surface of each driven-side convex portion and a circumferential side surface of each coupling-side convex portion.

2. The torque-transmission joint according to claim 1 ,
wherein the circumferential side surface of each drive-side convex portion is inclined in a direction in which a circumferential width size of each drive-side convex portion decreases towards one axial side in an engaging part of the drive-side concave-convex portion and the half portion on the other axial side of the coupling-side concave-convex portion, and
wherein the circumferential side surface of each driven-side convex portion is inclined in a direction in which a circumferential width size of each driven-side convex portion decreases towards the other axial side in an engaging part of the driven-side concave-convex portion and the half portion on one axial side of the coupling-side concave-convex portion.

3. The torque-transmission joint according to claim 1 ,
wherein the circumferential side surface of each coupling-side convex portion is inclined in a direction in which a circumferential width size of each coupling-side convex portion is greatest at an axially intermediate portion and decreases towards both axial end portions.

4. The torque-transmission joint according to claim 1 ,
wherein grease is interposed between both the drive-side and driven-side concave-convex portions and the coupling-side concave-convex portion.

5. The torque-transmission joint according to claim 4 ,
wherein at least one of the circumferential side surface of each of the drive-side and driven-side convex portions and the circumferential side surface of each coupling-side convex portion is provided with a plurality of minute concave portions.

6. The torque-transmission joint according claim 1 ,
wherein one circumferential surface of both the inner and outer circumferential surfaces of the coupling is formed with a coupling-side protrusion protruding in the radial direction, and
wherein the coupling-side protrusion is positioned between the drive-side transmission part and the driven-side transmission part in the axial direction.

7. The torque-transmission joint according to claim 1 ,
wherein both axial side surfaces of the coupling are formed with coupling-side groove portions at a plurality of places in the circumferential direction, and
wherein the coupling-side groove portions are arranged at positions at which the coupling-side groove portions overlap with coupling-side concave portions, which are formed between the coupling-side convex portions adjacent to each other in the circumferential direction and which configures the coupling-side concave-convex portion, in the circumferential direction.

8. The torque-transmission joint according to claim 7 ,
wherein a gap is formed between the drive-side convex portion and the coupling-side groove portion in the radial direction; and
wherein a gap is formed between the driven-side convex portion and the coupling-side groove portion in the radial direction.

9. A worm reduction gear comprising:
a housing;
a worm wheel rotatably supported to the housing;
a worm rotatably supported to the housing at a state where worm teeth provided on an axially intermediate portion thereof are meshed with the worm wheel; and
an electric motor configured to rotatively drive the worm;
wherein the worm and an output shaft of the electric motor are connected by a torque-transmission joint so that torque can be transmitted therebetween, and
wherein the torque-transmission joint is the torque-transmission joint according to claim 1 .

10. A torque-transmission joint configured to transmit torque between one axial end portion of a drive shaft and the other axial end portion of a driven shaft arranged in series with each other in an axial direction, the torque-transmission joint comprising:
a coupling provided on one circumferential surface of inner and outer circumferential surfaces with a coupling-side concave-convex portion having coupling-side convex portions arranged at a plurality of circumferential places and protruding in a radial direction;
a drive-side transmission part provided at one axial end portion of the drive shaft and provided on one circumferential surface, which faces the coupling-side concave-convex portion, of inner and outer circumferential surfaces with a drive-side concave-convex portion having drive-side convex portions arranged at a plurality of circumferential places and protruding in a radial direction; and
a driven-side transmission part is provided at the other axial end portion of the driven shaft and provided on one circumferential surface, which faces the coupling-side concave-convex portion, of inner and outer circumferential surfaces with a driven-side concave-convex portion having driven-side convex portions arranged at a plurality of circumferential places and protruding in a radial direction;
wherein the circumferential side surface of each drive-side convex portion is inclined in a direction in which a circumferential width size of each drive-side convex portion is decreases towards one axial side in an engaging part of the drive-side concave-convex portion and the half portion on the other axial side of the coupling-side concave-convex portion, and
wherein the circumferential side surface of each driven-side convex portion is inclined in a direction in which a circumferential width size of each driven-side convex portion is decreases towards the other axial side in an engaging part of the driven-side concave-co

Assignees

• Nsk Ltd

Inventors

• Oosawa Ryou

Classifications

• F16D3/18

  the coupling parts (1) having slidably-interengaging teeth · CPC title

• F16D2001/103

  the torque is transmitted via splined connections · CPC title

• F16H1/16

  comprising worm and worm-wheel · CPC title

• F16D1/10

  Quick-acting couplings in which the parts are connected by simply bringing them together axially · CPC title

• F16D1/02 Primary

  for connecting two abutting shafts or the like · CPC title