Rack and pinion steering gear

Claim 2

A rack and pinion automotive steering unit, including, a. a rack comprising two parts, a toothed member and a carrier member; b. the toothed member superposed on and drivingly connected to the carrier member, the toothed member encompassing a portion only of said carrier; c. a pinion and a casing; d. the carrier member movable in the casing by rotation of the pinion member which meshes with the toothed member; e. the carrier member spaced from the pinion; f. resilient means interposed between the toothed member and the carrier member to urge the toothed member against the pinion in order to reduce the backlash between the toothed member and the pinion.

Claim 3

The unit of claim 1 wherein said toothed member is of substantially part circular cross section.

Claim 4

The unit of claim 2 wherein the toothed member is formed wholly of metal.

Claim 5

The unit of claim 1, including, a. at least one piston carried by said carrier member, which divides said casing into at least two chambers into which hydraulic fluid can be introduced to urge the carrier member and hence the toothed member longitudinally of the casing; b. whereby power assistance may be imparted to the rack.

Claim 6

A rack and pinion steering unit as claimed in claim 4 in which: a. chambers are formed in the casing by means of two spaced pistons which are carried on the carrier member; b. each chamber having a port by which fluid can be introduced into it or exhausted from it to urge the carrier member and hence the toothed member in one longitudinal direction or the other within the casing; c. the stroke of each piston limited by an exhaust port which is associated with each piston, each exhaust port being positioned at the limit of the associated piston''s travel in one direction so that pressurized fluid is exhausted from the associated chamber when the piston reaches the limit, thus limiting the power stroke of the piston in that direction.

Claim 7

A rack and pinion steering unit as claimed in claim 5 in which the toothed member has portions at each of its ends which engage in the respective pistons to locate the toothed member radially.

Claim 8

A rack and pinion steering unit as claimed in claim 6 in which each end of the toothed member engages correspondingly shaped portions of the carrier member so that axial movement of the toothed member, by rotation of the pinion, is transmitted directly to the carrier member.

Claim 9

A rack and pinion steering unit as claimed in claim 4 in which the resilient member comprises a bowed leaf spring.

Claim 10

A rack and pinion steering unit as claimed in claim 4 in which the resilient member comprises a coiled spring.

Claim 11

The unit of claim 1 wherein the toothed member is formed of wholly metal.

Claim 12

A rack and pinion steering unit as claimed in claim 1 in which the esilient member comprises a bowed leaf spring.

Claim 13

A rack and pinion steering unit as claimed in claim 1 in which the resilient member comprises a coiled spring.

Claim 14

A rack and pinion automotive steering unit, including, a. a rack comprising two parts, a toothed member and a carrier member; b. the toothed member superposed on and drivingly connected to the carrier member, the toothed member encompassing a portion only of said carrier; c. a pinion and a casing; d. the carrier member movable in the casing by rotation of the pinion member which meshes with the toothed member; e. the carrier member spaced from the pinion; f. resilient means for urging the toothed member against the pinion to reduce backlash therebetween.

Claim 15

A rack and pinion automotive steering unit, including, a. a rack comprising two parts, a toothed member and a carrier member; b. the toothed member superposed on and drivingly connected to the carrier member, the toothed member encompassing a portion only of said carrier; c. a pinion and a casing; d. the carrier member movable in the casing by rotation of the pinion member which meshes with the toothed member; e. the carrier member spaced from the pinion; f. resilient means for urging the toothed member against the pinion to reduce backlash therebetween.