Manual steering is considered to be entirely adequate for smatter vehicles. It is tight. fast, and accurate in maintaining steering control. However, larger and heavier engines. greater front overhang on larger vehicles, and a trend toward wide tread tires have increased the steering effort required. Steering mechanisms with higher gear ratios were tried, but dependable power steering systems were found to be the answer. There are several different types of manual steering systems, which are as follows:
Worm and sector
Worm and Sector
Figure 8-20.- Worm and sector steering gear.
An adjusting nut or plug is provided for adjusting the end play of the worm gear.
Worm and Roller
The hourglass shape of the worm, which tapers from both ends to the center, affords better contact between the worm and roller in all positions. This design provides a variable steering ratio to permit faster and more efficient steering.
Figure 8-21.- Worm and roller steering gear.
"Variable steering ratio" means that the ratio is larger at one position than another. Therefore the wheels are turned faster at certain positions than at others. At the center or straight-ahead position, the steering gear ratio is high, giving more steering control. However, as the wheels are turned, the ratio decreases so that the steering action is much more rapid. This design is very helpful for parking and maneuvering the vehicle.
Cam and Lever