Gearbox

Wheeled Vehicle Sytems Steering Systems
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gearboxes are of two types: offset and inline.

The offset type has a recirculatingball gearbox with a rack meshed to the

pitman sector gear above or on the opposite side of the ball nut. The power

steering force is developed in the power piston, which is offset from the

worm and nut and attached to the rack.

The inline design uses the recirculating ballnut assembly as a power

piston. In this design, the ball nut is sealed inside a cylindrical portion

of the steering gear housing. The power steering effect is produced by

alternately pressurizing either side of the power piston.

Hydraulic cylinder

The hydraulic cylinder used on the semiintegral and integral power steering

systems is located on the steering linkage. The power assist is developed

in the cylinder through the action of the pressurized hydraulic fluid.

The cylinder may have single or doublewall construction. The hydraulic

hoses connect to the ports on each end of the singlewall cylinder. The

doublewall cylinder has connections on one end for both hoses and an

internal passageway between the walls to pressurize the other end of the

cylinder. Some linkage cylinders have shuttle valves built into the piston.

This valve opens at the end of the piston stroke. This feature helps

eliminate full hydraulic pressure from acting on the cylinder when the

piston is bottomed by opening and allowing fluid to flow through the piston.