Steering device

Patent metadata

Field	Value
Publication number	US-11192574-B2
Application number	US-201816634264-A
Country	US
Kind code	B2
Filing date	Jul 2, 2018
Priority date	Aug 10, 2017
Publication date	Dec 7, 2021
Grant date	Dec 7, 2021

Abstract

A rack housing (9) is provided with: a cylindrical main body (19) for movably accommodating a rack bar (8); and a stroke limiting section (25) annularly protruding from the cylindrical main body (19) toward a first end (9a). The inner peripheral surface (25b) of the stroke limiting section (25) is located offset radially outward from a support surface (19a), i.e. the inner peripheral surface of the cylindrical main body (19). The inner peripheral surface (25b) and the support surface (19a) are connected to each other by a sloped section (26) which is sloped circular conically. The sloped section (26) is provided at a position overlapping the cylindrical main body (19) when viewed radially. The sloped section (26) is sloped so that the inner diameter of the cylindrical main body (19) of the rack housing (9) increases toward a first contact section (25a).

First claim

The invention claimed is:

1. A steering device comprising:
a rack bar connected to a pair of ball joints, wherein the pair of ball joints include a first ball joint and a second ball joint;
a rack housing made of metal, and including a tubular body portion, a cushioning member accommodating portion, a stroke restricting portion, and a pair of ends, wherein the pair of ends include a first end and a second end, wherein:
the tubular body portion is structured to support the rack bar in a manner to allow the rack bar to travel;
with reference to a reference axis that is parallel to a direction of travel of the rack bar with respect to the rack housing, and passes through a center of a circle in a cross-sectional plane perpendicular to the direction of travel of the rack bar, wherein the circle is defined by an inner peripheral surface of the tubular body portion,
the cushioning member accommodating portion is disposed to be closer to the first end than the tubular body portion along the reference axis, and be outside the rack bar in a radial direction with respect to the reference axis, and has a recessed shape opening to the first end along the reference axis;
the stroke restricting portion is disposed inside the cushioning member accommodating portion in the radial direction with respect to the reference axis;
along the reference axis, the stroke restricting portion overlaps with the cushioning member accommodating portion, and is closer to the first end than the tubular body portion, and projects toward the first end, and includes a first contact portion structured to be in contact with the first ball joint; and
the stroke restricting portion has an inner diameter as a dimension in the radial direction with respect to the reference axis, wherein the inner diameter is greater than a minimum value of inner diameter of the tubular body portion as a dimension in the radial direction with respect to the reference axis; and

a cushioning member disposed at the cushioning member accommodating portion, and made of an elastic material, and including a cushioning portion, wherein:
the cushioning member is structured to be compressed between the tubular body portion and the first ball joint, and includes a second contact portion structured to be in contact with the first ball joint; and
the second contact portion is closer to the first end than the first contact portion along the reference axis,

wherein:
the rack housing includes an inclined portion; and
the inclined portion is formed in a region from the tubular body portion to the stroke restricting portion along the reference axis such that an inner diameter of the rack housing that is a dimension in the radial direction with respect to the reference axis increases gradually toward the first contact portion.

2. The steering device as claimed in claim 1 , wherein the inclined portion has a shape fitted to a deflected shape of the rack bar in contact with the inner peripheral surface of the tubular body portion.

3. The steering device as claimed in claim 1 , wherein:
the inclined portion has a pair of ends along the reference axis; and
the pair of ends include an end that is farther from the first end and is located to overlap with the tubular body portion along the reference axis.

4. The steering device as claimed in claim 1 , wherein:
the rack housing is a casting formed by casting; and
the inclined portion has a casting surface.

5. The steering device as claimed in claim 1 , wherein:
the rack housing is a casting formed by casting; and
the cushioning member accommodating portion, the stroke restricting portion, and the inclined portion are of an article integrally formed with a single casting mold.

6. The steering device as claimed in claim 1 , wherein:
in a sectional plane containing the reference axis, the stroke restricting portion has a radial thickness as a dimension in the radial direction with respect to the reference axis; and
the radial thickness decreases gradually from the tubular body portion to the first end.

7. The steering device as claimed in claim 1 , wherein the rack housing includes an inner peripheral surface shaped to be smoothly continuous in a region from the tubular body portion to the inclined portion along the reference axis in a sectional plane containing the reference axis.

8. The steering device as claimed in claim 1 , wherein the rack housing includes an inner peripheral surface including a supporting surface structured to support the rack bar directly.

9. A steering device comprising:
a rack bar connected to a first ball joint and a second ball joint;
a rack housing including:
a tubular body portion configured to support the rack bar such that the rack bar is movable relative to the tubular body portion along an axial direction of the rack housing,
a first end,
a second end,
a cushion member accommodating extension extending from the tubular body portion towards the first end along the axial direction, and
a stroke restricting extension extending from the tubular body portion, positioned axially inward relative to the first end, and positioned axially overlapping with and radially inward relative to the cushion member accommodating extension, wherein:
the stroke restricting extension includes a first contact portion structured to be in contact with the first ball joint; and
the stroke restricting extension has an inner diameter greater than a minimum inner diameter of the tubular body portion; and

an elastic cushion disposed adjacent the cushion member accommodating extension, wherein:
the cushion is compressible between the tubular body portion and the first ball joint, and includes a second contact portion structured to be in contact with the first ball joint; and
the second contact portion is closer to the first end than the first contact portion along the axial direction,
wherein the rack housing further includes an inclined portion formed in a region from the tubular body portion to the stroke restricting extension along the axial direction such that an inner diameter of the rack housing increases along the axial direction toward the first contact portion.

Assignees

• Hitachi Automotive Systems Ltd
• Hitachi Astemo Ltd

Inventors

• Kitamura Keisuke
• Kimura Norihiro
• Yoshida Osamu

Classifications

• B62D3/12 Primary

  of rack-and-pinion type · CPC title

• B62D3/126 Primary

  characterised by the rack · CPC title