US 6,178,843 B2Granted

Rack guide in rack and pinion type steering system

AssigneeDaido Metal Company Ltd.

InventorsKatsuhiro Machida, Nobumitsu Mabuchi, Yasuo Ido

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Abstract

In a rack guide disposed in a casing of a rack and pinion type steering system for slidably supporting a rack bar having rack teeth which engage with a pinion rotatably supported in the casing, the area for bearing the load of the rack bar can be fixed. A slide bearing member 21 has a three-layered structure consisting of a backing metal 22 made of bronze, a sintered alloy layer 23 and a synthetic resin layer 24, the surface of the synthetic resin layer 24 comprising sliding-contact surface portions 25, 26 formed intermittently with the center thereof at the center of curvature “O” of a circular outer peripheral surface of a rack bar 16 and with a radius of curvature equal to the radius of curvature R0 of the same, and the remaining surface portions 27 to 29 formed in other positions than the sliding-contact surface portions 25, 26 so as to be more dented than the sliding-contact surface portions 25, 26.

Claims8

Dependent claims

A rack guide for a rack and pinion steering system, in which the rack guide is mounted in a casing of the steering system so as to slidably support a rack bar which is reciprocatingly driven by a pinion being rotatably supported in the casing, the rack guide comprising

supporting base and an elongated slide bearing member which is mounted on the supporting base and which has a circular-arc cross-sectional profile, wherein
the slide bearing member comprises a backing metal layer and liner formed on the backing metal, the liner comprising a synthetic resin layer which forms an inner surface of the rack guide and which is brought into sliding contact with the rack bar;
the inner surface of the rack guide, having said circular-arc cross-sectional profile, comprises circular-arc concave sliding-contact surface portions (25, 26) and circular-arc concave remaining surface portions (27, 28, 29), all of which are elongated longitudinally and which are circumferentially distinguished from one another;
the sliding-contact surface portions (25, 26) are entirely in sliding contact with the rack bar and have a cross sectional circular-arc profile with a predetermined circumferential length having a first radius of curvature (R0), and which are continuous to the adjacent remaining surface portions;
and
the remaining surface portions (27, 28, 29) are radially more recessed than the sliding-contact surface portions with first and second remaining surface portions (28, 29) being located adjacent the edges of said circular-arc profile and each having a second radius of curvature (R2) which is less than said first radius of curvature (Ro), and with a third remaining surface portion (27) being located between said sliding-contact surface portions (25, 26) along a symmetric center line (L) of a said profile and having a third radius of curvature (R1) which is less than said first radius of curvature (Ro).

3 more elements

a supporting base and an elongated slide bearing member which is mounted on the supporting base and which has a circular-arc cross-sectional profile, wherein
the slide bearing member comprises a backing metal layer and a liner formed on the backing metal, the liner comprising a synthetic resin layer which forms an inner surface of the rack guide and which is brought into sliding contact with the rack bar;
the inner surface of the rack guide, having said circular-arc cross-sectional profile, comprises circular-arc concave sliding-contact surface portions (25, 26) and circular-arc concave remaining surface portions (27, 28, 29), all of which are elongated longitudinally and which are circumferentially distinguished from one another;
the sliding-contact surface portions (25, 26) are entirely in sliding contact with the rack bar and have a cross sectional circular-arc profile with a predetermined circumferential length having a first radius of curvature (R0), and which are continuous to the adjacent remaining surface portions;
and
the remaining surface portions (27, 28, 29) are radially more recessed than the sliding-contact surface portions with first and second remaining surface portions (28, 29) being located adjacent the edges of said circular-arc profile and each having a second radius of curvature (R2) which is less than said first radius of curvature (R0), and each of which has a center point (O2, O3) located (1) between a symmetric center line (L) of a said profile and said supporting base, and also (2) within a semicircular area defined by said circular-arc cross-sectional profile;
and
with a third remaining surface portion (27) being located between said sliding-contact surface portions (25, 26) along said symmetric center line (L) of a said profile and having a third radius of curvature (R1) which is less than said first radius of curvature (R0).

5 more elements

Dependencies are inferred from the claim text.