Power steering device

Patent metadata

Field	Value
Publication number	US-10077067-B2
Application number	US-201415107923-A
Country	US
Kind code	B2
Filing date	Dec 11, 2014
Priority date	Dec 25, 2013
Publication date	Sep 18, 2018
Grant date	Sep 18, 2018

Abstract

A power steering device includes a worm shaft configured to rotate as an electric motor is driven; a worm wheel meshed with the worm shaft, the worm wheel being configured to transmit a rotational force of the electric motor to a rack shaft configured to turn wheels; a bearing that rotatably supports a tip side of the worm shaft; a gear case that houses the worm shaft; a biasing member configured to bias the worm shaft toward the worm wheel via the bearing; and a holder including a housing hole configured to house the bearing movably in a biasing direction of the biasing member. The holder includes a plurality of bulging parts formed to bulge radially outwardly, the bulging parts being configured to come into contact with an inner peripheral surface of the gear case.

First claim

The invention claimed is:

1. A power steering device, comprising:
a worm shaft configured to rotate as an electric motor is driven;
a worm wheel meshed with the worm shaft, the worm wheel being configured to transmit a rotational force of the electric motor to a rack shaft configured to turn wheels;
a bearing that rotatably supports a tip side of the worm shaft;
a gear case that houses the worm shaft;
a biasing member configured to bias the worm shaft toward the worm wheel via the bearing; and
a holder including:
a housing hole configured to house the bearing movably in a biasing direction of the biasing member,
a holder main body formed with the housing hole, and
a support member to be mounted on an outer peripheral surface of the holder main body, wherein

the support member includes:
a close-contact portion to be held in close contact with the outer peripheral surface of the holder main body, and
a plurality of bulging parts formed to bulge radially outwardly, the bulging parts being configured to come into contact with an inner peripheral surface of the gear case, and

the close-contact portion faces the inner peripheral surface of the gear case with a clearance defined between the close-contact portion and the inner peripheral surface of the gear case.

2. The power steering device according to claim 1 , wherein:
the support member has a C shape with an open part, and
the bulging parts are formed at positions across the open part and at a position facing the open part.

3. The power steering device according to claim 1 , wherein:
the support member includes a pair of leaf spring parts inserted through a pair of through holes formed on the holder main body and configured to bias the bearing from positions symmetrical with respect to the biasing direction of the biasing member.

4. The power steering device according to claim 1 , wherein:
the support member includes a projection on the close-contact portion, the projection being fitted into a groove part formed on the outer peripheral surface of the holder main body.

5. The power steering device according to claim 1 , wherein:
the support member includes a claw piece configured to prevent the bearing from coming out of the housing hole of the holder main body.

6. A power steering device, comprising:
a worm shaft configured to rotate as an electric motor is driven;
a worm wheel meshed with the worm shaft, the worm wheel being configured to transmit a rotational force of the electric motor to a rack shaft configured to turn wheels;
a bearing that rotatably supports a tip side of the worm shaft;
a gear case that houses the worm shaft;
a biasing member configured to bias the worm shaft toward the worm wheel via the bearing; and
a holder including a housing hole configured to house the bearing movably in a biasing direction of the biasing member, wherein
the holder includes a plurality of bulging parts formed to bulge radially outwardly, the bulging parts being configured to come into contact with an inner peripheral surface of the gear case,
the holder includes:
a holder main body formed with the housing hole, and
a support member to be mounted on an outer peripheral surface of the holder main body,

the support member includes:
a close-contact portion to be held in close contact with the outer peripheral surface of the holder main body, and
the bulging parts formed to bulge radially outwardly, and

the support member includes a projection on the close-contact portion, the projection being fitted into a groove part formed on the outer peripheral surface of the holder main body.

7. A power steering device, comprising:
a worm shaft configured to rotate as an electric motor is driven;
a worm wheel meshed with the worm shaft, the worm wheel being configured to transmit a rotational force of the electric motor to a rack shaft configured to turn wheels;
a bearing that rotatably supports a tip side of the worm shaft;
a gear case that houses the worm shaft;
a biasing member configured to bias the worm shaft toward the worm wheel via the bearing; and
a holder including a housing hole configured to house the bearing movably in a biasing direction of the biasing member, wherein
the holder includes a plurality of bulging parts formed to bulge radially outwardly, the bulging parts being configured to come into contact with an inner peripheral surface of the gear case,
the holder includes:
a holder main body formed with the housing hole, and
a support member to be mounted on an outer peripheral surface of the holder main body,

the support member includes:
a close-contact portion to be held in close contact with the outer peripheral surface of the holder main body, and
the bulging parts formed to bulge radially outwardly, and

the support member includes a claw piece configured to prevent the bearing from coming out of the housing hole of the holder main body.

Assignees

• Kyb Corp

Inventors

• Uchihara Masato
• Okumura Kazuyuki
• Yoshikawa Shinraku
• Shimoda Katsumi

Classifications

• B62D3/04

  of worm type · CPC title

• B62D5/0403

  characterised by constructional features, e.g. common housing for motor and gear box · CPC title

• B62D5/0409 Primary

  Electric motor acting on the steering column · CPC title

• F16H2057/0222

  Lateral adjustment · CPC title

• F16H2057/0213

  Support of worm gear shafts · CPC title