Torque transmission joint and electric power steering device

Patent metadata

Field	Value
Publication number	US-2019264751-A1
Application number	US-201716307633-A
Country	US
Kind code	A1
Filing date	Oct 12, 2017
Priority date	Oct 13, 2016
Publication date	Aug 29, 2019
Grant date	—

Abstract

A first concave-convex portion of a first transmission member is engaged with an intermediate concave-convex portion of an intermediate transmission member with a circumferential gap being therebetween. A second concave-convex portion of a second transmission member is engaged with the intermediate concave-convex portion with a circumferential gap being therebetween. A first elastic member and a second elastic member are engaged with a first engagement portion and a second engagement portion of the intermediate transmission member such that separation between the intermediate transmission member and the first elastic member and the second elastic member can be prevented.

First claim

1 . A torque transmission joint comprising:
an intermediate transmission member which includes:
a main body portion including an intermediate concave-convex portion formed by alternately arranging concave portions and convex portions in a circumferential direction on one radial side periphery;
first tooth portions provided at a plurality of circumferential positions on one axial side surface of the main body portion to protrude in an axial direction;
second tooth portions provided at a plurality of circumferential positions on another axial side surface of the main body portion to protrude in the axial direction;
a first engagement portion provided in at least one of the first tooth portions; and
a second engagement portion provided in at least one of the second tooth portions;
a first elastic member which is formed of an elastic material to have an annular shape and is configured to transmit torque with the intermediate transmission member by engaging with the first tooth portions and to be restricted from being displaced to one axial side with respect to the intermediate transmission member by engaging with the first engagement portion; a second elastic member which is formed of an elastic material to have an annular shape and is configured to transmit torque with the intermediate transmission member by engaging with the second tooth portions and to be restricted from being displaced to another axial side with respect to the intermediate transmission member by engaging with the second engagement portion; a first transmission member which includes a first concave-convex portion formed by alternately arranging concave portions and convex portions in the circumferential direction on another radial side periphery, wherein the first concave-convex portion is engaged with the first elastic member such that torque can be transmitted and is engaged with one axial end portion of the intermediate concave-convex portion with a circumferential gap being interposed therebetween such that torque can be transmitted; and a second transmission member which includes a second concave-convex portion formed by alternately arranging concave portions and convex portions in the circumferential direction on another radial side periphery, wherein the second concave-convex portion is engaged with the second elastic member such that torque can be transmitted and is engaged with another axial end portion of the intermediate concave-convex portion with a circumferential gap being interposed therebetween such that torque can be transmitted.

2 . The torque transmission joint according to claim 1 ,
wherein the first concave-convex portion is engaged with the one axial end portion of the intermediate concave-convex portion in a state where the circumferential gap interposed therebetween is larger than a circumferential gap interposed between the first concave-convex portion and the first elastic member at an engagement portion therebetween.

3 . The torque transmission joint according to claim 1 ,
wherein the second concave-convex portion is engaged with the another axial end portion of the intermediate concave-convex portion in a state where the circumferential gap interposed therebetween is larger than a circumferential gap interposed between the second concave-convex portion and the second elastic member at an engagement portion therebetween.

4 . The torque transmission joint according to claim 1 ,
wherein the first engagement portion is provided on a radial side surface of the at least one of the first tooth portions, and the second engagement portion is provided on a radial side surface of the at least one of the second tooth portions.

5 . The torque transmission joint according to claim 4 ,
wherein, as the first engagement portion, a first inclined engaging surface portion which is inclined in a direction in which a width dimension of the first tooth portion in the radial direction increases as proceeding toward one axial side or a first engagement protrusion protruding in the radial direction is provided on at least one of one radial side surface and another radial side surface of the at least one of the first tooth portions, and wherein, as the second engagement portion, a second inclined engaging surface portion which is inclined in a direction in which a width dimension of the second tooth portion in the radial direction increases as proceeding toward the other axial side or a second engagement protrusion protruding in the radial direction is provided on at least one of one radial side surface and another radial side surface of the at least one of the second tooth portions.

6 . The torque transmission joint according to claim 1 ,
wherein a positioning side surface which is in contact with or closely facing an axial side surface of a coupling body of the intermediate transmission member, the first elastic member and the second elastic member is provided on at least one of the first transmission member and the second transmission member.

7 . The torque transmission joint according to claim 1 ,
wherein an axial side surface of a coupling body of the intermediate transmission member, the first elastic member and the second elastic member has an inclined side surface portion which is inclined in a direction toward an axially center side of the coupling body as proceeding toward another radial side.

8 . The torque transmission joint according to claim 1 ,
wherein a circumferential width dimension of a convex portion configuring at least one of the first concave-convex portion and the second concave-convex portion decreases as proceeding toward an axially center side of the intermediate transmission member.

9 . An electric power steering device comprising:
a rotary shaft which is rotatably supported to a housing; a worm wheel which is supported coaxially with the rotary shaft and configured to rotate together with the rotary shaft; a worm which includes a worm shaft and worm teeth provided on an outer periphery of the worm shaft and is rotatably supported to the housing with the worm teeth being meshed with the worm wheel; and an electric motor which is configured to rotate the worm, wherein an output shaft of the electric motor which is a driving shaft and the worm shaft which is a driven shaft are connected by a torque transmission joint such that torque can be transmitted, wherein the torque transmission joint is the torque transmission joint according to claim 1 , and wherein the first transmission member is fixed to or integrally formed with a tip portion of the output shaft of the electric motor, and the second transmission member is fixed to or integrally formed with a base end portion of the worm shaft.

10 . The electric power steering device according to claim 9 , further comprising:
a preload applying mechanism which is provided between a tip portion of the worm shaft and the housing and configured to elastically press the worm toward the worm wheel.

Assignees

• Nsk Ltd

Inventors

• Oosawa Ryou
• Segawa Toru
• Ishii Toru

Classifications

• F16H2057/126

  Self-adjusting during operation, e.g. by a spring · CPC title

• F16H57/12

  Arrangements for adjusting or for taking-up backlash not provided for elsewhere · CPC title

• B62D5/0409

  Electric motor acting on the steering column · CPC title

• F16D3/74 Primary

  the intermediate member or members being made of rubber or other {rubber-like} flexible material · CPC title

• F16H1/16

  comprising worm and worm-wheel · CPC title