Power steering device

Patent metadata

Field	Value
Publication number	US-9415799-B2
Application number	US-201314655334-A
Country	US
Kind code	B2
Filing date	Dec 16, 2013
Priority date	Dec 26, 2012
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

A power steering device for assisting a steering force applied to a steering wheel by a driver includes a worm shaft that rotates in association with driving of an electric motor, a worm wheel that meshes with the worm shaft and transmits a rotational force of the electric motor to a rack shaft steering a wheel, a bearing that supports a tip end side of the worm shaft, a gear case that houses the worm shaft, a lid that closes an opening formed in a tip end portion of the gear case, a first elastic portion arranged in a compressed manner between the gear case and the lid, and a second elastic portion arranged between an inner circumferential surface of the gear case and an outer circumferential surface of the bearing. The first and the second elastic portion are formed in an integrated manner via a small thickness portion.

First claim

The invention claimed is:

1. A power steering device for assisting a steering force applied to a steering wheel by a driver, the power steering device comprising:
a worm shaft that rotates in association with driving of an electric motor;
a worm wheel that meshes with the worm shaft, the worm wheel being configured to transmit a rotational force of the electric motor to a rack shaft steering a wheel;
a bearing that rotatably supports a tip end side of the worm shaft;
a gear case that houses the worm shaft;
a lid that closes an opening formed in a tip end portion of the gear case;
a first elastic portion arranged in a compressed manner between the gear case and the lid; and
a second elastic portion arranged between an inner circumferential surface of the gear case and an outer circumferential surface of the bearing, wherein
the first elastic portion and the second elastic portion are formed in an integrated manner via a small thickness portion therebetween.

2. The power steering device according to claim 1 , wherein
the small thickness portion is formed in such a manner that a thickness thereof does not allow compression of the small thickness portion between the gear case and the lid.

3. The power steering device according to claim 1 , wherein
the first elastic portion has a seal portion, the seal portion being compressed and deformed by coming into contact with a seal surface of at least one of the gear case and the lid, and
the small thickness portion is formed continuously with the seal portion, and has a gap between the small thickness portion and the seal surface.

4. The power steering device according to claim 3 , wherein
the seal portion of the first elastic portion has a circular shape.

5. The power steering device according to claim 1 , further comprising
a third elastic portion formed in an integrated manner together with the first elastic portion and the second elastic portion, the third elastic portion being arranged in a compressed manner between the bearing and the lid.

6. The power steering device according to claim 1 , further comprising
a biasing member that biases the worm shaft towards the worm wheel by applying a biasing force to the bearing.

Assignees

• Kayaba Industry Co Ltd
• Kyb Corp

Inventors

• Yoshikawa Shinraku
• Shimoda Katsumi

Classifications

• B62D5/0409 Primary

  Electric motor acting on the steering column · CPC title

• F16H55/24

  Special devices for taking up backlash · CPC title

• B62D5/0412

  the axes of motor and steering column being parallel · CPC title

• F16C27/06

  by means of parts of rubber or like materials (F16C27/08 takes precedence; with sliding surfaces of rubber or synthetic rubber F16C33/22) · CPC title

• F16C27/04

  Ball or roller bearings, e.g. with resilient rolling bodies · CPC title