US 6,681,885 B2 · Rack and pinion steering gear with powdered metal bushing

Abstract

A rack and pinion steering apparatus (10) comprises a housing (12). Helical teeth (60) of a pinion gear (54) meshingly engage teeth of a rack bar (42) and, during rotation of the pinion gear (54), result in an axial force. A shaft (86) connects with the pinion gear (54). Rotation of the shaft (86) effects rotation of the pinion gear (54). An assembly is interposed between the shaft (86) and the housing (12). The assembly comprises a first snap ring (142) that is attached to the shaft (86) and a second snap ring (144) that is attached to the housing (12). Interposed between the first and second snap rings (142 and 144) are only a fluid tight seal (146) for blocking fluid leakage from the housing (12) and a bushing (108) for enabling rotation of the shaft (86) relative to the housing (12) and for engaging the first snap ring (142) to block axial displacement of the pinion gear (54) due to the axial force acting on the pinion gear (54).

Drawings

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Drawings

Claims8

Dependent claims

A rack and pinion steering apparatus for turning steerable wheels of a vehicle in response to rotation of a steering wheel, the apparatus comprising:

a housing;
a rack bar extending through the housing and movable relative to the housing for turning the steerable wheels of the vehicle, the rack bar having a plurality of teeth;
a pinion gear located within the housing and being rotatable relative to the housing, the pinion gear including a plurality of helical teeth that meshingly engage teeth of the rack bar, engagement of the helical teeth of the pinion gear with the teeth of the rack bar during rotation of the pinion gear in a first direction resulting in an axial force acting on the pinion gear;
a shaft connectable with the steering wheel of the vehicle and being rotatable relative to the housing, at least a portion of the shaft extending into the housing and connecting with the pinion gear, rotation of the shaft effecting rotation of the pinion gear;
and
an assembly interposed between the shaft and the housing, the assembly comprising a first snap ring that is attached to the portion of the shaft extending into the housing and a second snap ring that is attached to the housing, interposed between the first and second snap rings are only a fluid tight seal for blocking fluid leakage from the housing and a bushing for enabling rotation of the shaft relative to the housing, the bushing including a radially extending surface for engaging the first snap ring to block axial displacement of the pinion gear due to the axial force acting on the pinion gear,
wherein the bushing is formed from powered metal, and a percentage of iron in the powdered metal ranges from 91.1% to 95.4%, a percentage of copper in the powdered metal ranges from 4.0% to 0.9%, and a percentage of carbon in the powdered metal ranges from 0.6% to 0.9%.

4 more elements

A rack and pinion steering apparatus for turning steerable wheels of a vehicle in response to rotation of a steering wheel, the apparatus comprising:

a housing;
a rack bar extending through the housing and movable relative to the housing for turning the steerable wheels of the vehicle, the rack bar having a plurality of teeth;
a pinion gear located within the housing and being rotatable relative to the housing, the pinion gear including a plurality of helical teeth that meshingly engage teeth of the rack bar, engagement of the helical teeth of the pinion gear with the teeth of the rack bar during rotation of the pinion gear in a first direction resulting in an axial force acting on the pinion gear;
a shaft connectable with the steering wheel of the vehicle and being rotatable relative to the housing, at least a portion of the shaft extending into the housing and connecting with the pinion gear, rotation of the shaft effecting rotation of the pinion gear;
and
an assembly interposed between the shaft and the housing, the assembly comprising a first snap ring that is attached to the portion of the shaft extending into the housing and a second snap ring that is attached to the housing, interposed between the first and second snap rings are only a fluid tight seal for blocking fluid leakage from the housing and a bushing for enabling rotation of the shaft relative to the housing, the bushing including a radially extending surface for engaging the first snap ring to block axial displacement of the pinion gear due to the axial force acting on the pinion gear,
wherein the bushing includes a pocket for receiving the first snap ring, the pocket being partially defined by the radially extending surface.

4 more elements

A rack and pinion steering apparatus for turning steerable wheels of a vehicle in response to rotation of a steering wheel, the apparatus comprising:

a housing;
a rack bar extending through the housing and movable relative to the housing for turning the steerable wheels of the vehicle, the rack bar having a plurality of teeth;
a pinion gear located within the housing and being rotatable relative to the housing, the pinion gear including a plurality of helical teeth that meshingly engage teeth of the rack bar, engagement of the helical teeth of the pinion gear with the teeth of the rack bar during rotation of the pinion gear in a first direction resulting in an axial force acting on the pinion gear;
a shaft connectable with the steering wheel of the vehicle and being rotatable relative to the housing, at least a portion of the shaft extending into the housing and connecting with the pinion gear, rotation of the shaft effecting rotation of the pinion gear;
and
an assembly interposed between the shaft and the housing, the assembly comprising a first snap ring that is attached to the portion of the shaft extending into the housing and a second snap ring that is attached to the housing, interposed between the first and second snap rings are only a fluid tight seal for blocking fluid leakage from the housing and a bushing for enabling rotation of the shaft relative to the housing, the bushing being a unitary structure having an annular outer surface for engaging the housing and an annular inner surface for engaging the portion of the shaft extending into the housing, the annular inner surface of the bushing being fixed relative to and being coaxial with the annular outer surface of the bushing, the bushing further including a radially extending surface for engaging the first snap ring to block axial displacement of the pinion gear due to the axial force acting on the pinion gear,
wherein the bushing is formed from powdered metal and is self-lubricating.

4 more elements

Dependencies are inferred from the claim text.

Description5,343 words

Summary718 words

#The present invention relates to a rack and pinion steering gear. More particularly, the present invention relates to a rack and pinion steering gear with a pinion gear having helical teeth.

#A known rack and pinion steering gear includes a housing. A rack bar extends longitudinally through the housing and has opposite ends that are connectable with the steerable wheels of the vehicle. A portion of the rack bar extending through the housing includes teeth. As the rack bar is moved linearly relative to the housing, the steerable wheels of the vehicle are turned.

#The known rack and pinion steering gear also includes a pinion gear. The pinion gear includes a plurality of helical teeth. The pinion gear is located within the housing so that the helical teeth of the pinion gear are in meshing engagement with the teeth of the rack bar. The pinion gear is rotatable relative to the housing.

Brief description of the drawings5 figures

#The foregoing and other features of the present invention will become apparent to those skilled in the art to which the present invention relates upon reading the following description with reference to the accompanying drawings, in which:

#FIG. 1 is a sectional elevation view of a rack and pinion steering gear constructed in accordance with the present invention and showing a first snap ring axially spaced from a powdered metal bushing;

#FIG. 1A is an enlarged view of a portion of FIG. 1;

Detailed description4,478 words

#The figures that are referred to hereinafter illustrate a rack and pinion steering gear 10 having a pinion nut 68 that has loosened. Although the loosening of a pinion nut of a rack and pinion steering gear is a rare occurrence, the rack and pinion steering gear 10 constructed in accordance with the present invention includes provisions for maintaining the integrity of the steering gear should the pinion nut loosen.

#FIG. 1 is a sectional elevation view of a rack and pinion steering gear 10 constructed in accordance with the present invention. The rack and pinion steering gear 10 of FIG. 1 is a hydraulic power-assisted rack and pinion steering gear.

#The rack and pinion steering gear 10 includes a housing 12. The housing 12 includes a first tubular portion 14 that extends axially along axis A. The first tubular portion 14 of the housing 12 has first and second axial ends 16 and 18, respectively, and cylindrical inner and outer surfaces 20 and 22, respectively. The inner surface 20 of the first tubular portion 14 of the housing 12 defines a passage 24 that extends axially through the first tubular portion 14.

Facts

Application

09/956,406Filed 19 Sep 2001

Published

US 2003/0052468 A120 Mar 2003

Granted

27 Jan 2004

Term ended

21 Nov 2021

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 63 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification3 codes

B62D 5/22
Specially adapted for particular type of steering gear or particular application: for rack-and-pinion type
B62D 3/12
Mechanical: of rack-and-pinion type
B62D
Motor vehicles

Timeline

19 Sep 2001Application filedUS 09/956,406
19 Sep 2001Assigned to Trw Inc.assignment of assignor's interest
20 Mar 2003PublishedUS 2003/0052468 A1
28 Apr 2003Assigned to Jpmorgan Chase Bankthe us guarantee and collateral agreement
27 Jan 2004GrantedUS 6,681,885 B2
21 Dec 2012Assigned to Jpmorgan Chase Bank, N.A., AS Collateral Agentsecurity agreement
15 Nov 2013Assigned to Trw Vehicle Safety Systems Inc., Trw Automotive U.S. LLC, Kelsey-Hayes Company, Trw Intellectual Property Corp.release of security interest
21 Nov 2021Term endedEstimated, includes 63 days of adjustment

Rack and pinion steering gear with powdered metal bushing

Life of this patent

Rack and pinion steering gear with powdered metal bushing

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims8

Description5,343 words

Drawings

Classification3 codes

Life of this patent

Description5,343 words