Saginaw Recirculating Ball Gear Manual Steering

Fig. 1 Cross-Sectional View Of Steering Gear:

The Saginaw steering gear, Fig. 1, is a recirculating ball nut and worm type. The ball nut is mounted on the worm, located on the lower end of the steering shaft. The steel balls act as a rolling thread between the worm and nut to provide low friction drive between them.

Teeth on the ball nut engage teeth on the pitman shaft sector. The teeth on the ball nut are made so that a tighter fit exists between the ball nut and pitman shaft sector teeth when the front wheels are in the straight ahead position. The pitman shaft sector teeth are slightly tapered so that a proper preload may be obtained by moving the pitman shaft endways by means of a preload adjuster screw which extends through the gear housing side cover. The head of the preload adjuster and a selectively fitted shim fit snugly into a T-slot in the end of the pitman shaft, so that the screw also controls the end play of the shaft.

When the wheel and steering shaft turn to the left, the ball nut is moved downward by the balls which roll between the worm and nut. As the balls reach the outer surface of the nut, they enter the return guides which direct them across and down into the ball nut where they enter the circuit again.When a right turn is made, the ball nut moves upward and the balls circulate in the reverse direction.