Chapter 25 Steering Systems 505
connected between the upper and lower steer-
ing shafts. The disc is fi rm enough to accurately
transmit steering effort between the shafts.
Vibrations and road shocks transmitted from
the lower shaft twist the rubber instead of trav-
eling to the upper shaft.
Steering Shaft Universal Joint
Many steering shafts have one or more uni-
versal joints, which allow the shaft to be located
at various convenient angles without moving
the steering gear. Universal joints also relieve
the mounting stresses and defl ecting (bending)
forces sometimes encountered in a solid shaft.
In addition, the universal joint dampens steer-
ing shock and vibration transfer to the steering
wheel. See Figure 25-16.
Rack-and-pinion
assembly
Electric
motor
Figure 25-15.
The four-wheel steering system installed on the rear axle
of this truck uses a stepper motor to operate a rack-and-
pinion steering gear. The vehicle’s computer controls the
motor.
Delphi/PRNewswire)
Outer
tie rod
Inner
tie rod
Outer
tie rod
Inner
tie rod
Universal
joints
Collapsible
shaft
Tilt
mechanism
Rack-and-pinion
steering gear
Figure 25-16.
A steering column used with a motor assisted rack-and-pinion steering gear. The universal joints in the column allow steering
wheel turning force to travel through several angles. The tilt mechanism is located at the top of the steering column.
ThyssenKrupp