The steering gear mechanism is an important term in the vehicle direction system. In this system, the two theories are explained and discussed. In this article, I will discuss the two types of string gear mechanisms and their advantages in automobiles.
Steering Gear Mechanism
There are two types of steering gear mechanisms-
- Davis steering gear
- Ackermann steering gear.
The main difference between the two steering gear mechanisms is that the Davis steering gear has sliding pairs, whereas the Ackermann steering gear has only turning pairs. The sliding pair has more friction than the turning pair, therefore, the Davis steering gear will wear out earlier and become inaccurate after a certain time.
However, the Ackermann steering gear is not mathematically accurate except in three positions, contrary to the Davis steering gear which is mathematically correct in all positions. However, the Ackermann steering gear is preferred to the Davis steering gear.
All these 2 types of steering gear mechanisms are discussed below –
#1. Davis Steering Gear Mechanism
The Davis steering gear mechanism consists of a cross-link KL sliding parallel to another link AB. It is connected to the stub axles of the two front wheels using two similar bell crank levers ACK and DBK pivoted at A and B respectively.
The cross-link KL slides in the bearing and carries pins at its end K and L. The slide blocks are pivoted on these pins and move with the turning of bell crank levers as the steering wheel is operated. When the vehicle runs straight, the gear is said to be in its mid position. The sort arms AK and BL inclined an angle 90 + a to their stub axles AC and BD respectively. The correct steering depends upon the suitable selection of cross-arm single a and is given by
tan α =b/21
b= AB = distance between the pivots of front axles,
The range of b/1 is 0.4 to 0.5, hence angle lies between 11.3 and 14.1°
#2. Ackermann Steering Gear Mechanism
The Ackermann steering gear mechanism consists of a cross-link KL connected to the short axles AC and BD of the two front wheels through the short arms AK and BL, forming bell crank levers CAK and DBL respectively.
When the vehicle is running straight, the crosslink KL is parallel to AB, and the short arm AK and BL both make angle α to the horizontal axis of the chassis. To satisfy the fundamental equation for correct steering, the links AK and KL are suitably proportioned, and angle α is suitably selected.
For correct steering, cotØ-cosθ=b/1
The angles, Ø and θ are shown in the FIG. The value of B/L is between 0.4 and 0.5, generally 0.455. The value of cotθ-cotθ corresponds to the positions when the steering is correct. There are three values of angle θ which give correct steering of the vehicle, first while it is turning to right, second while it is turning to left, and third while it is running straight.
The steering gear mechanism is the main factor that helps to drive the gearbox smoothly and accurately. These are the mechanisms where the torque transmission of the steering wheel and the driving of the wheels are covered. If you like the article then please share.
Frequently Asked Questions(FAQ’S)
How does a Rack and Pinion Steering Mechanism work?
In a rack and pinion system, the steering wheel’s rotation is transferred to a pinion gear, which engages with a linear rack. As the pinion gear rotates, it moves the rack side-to-side, causing the wheels to turn left or right.
How often should I check and maintain my Steering Gear Mechanism?
It is recommended to include steering system checks in routine vehicle maintenance. Inspections should be conducted regularly, and any signs of wear, damage, or abnormal behavior should be addressed promptly to prevent potential safety hazards.
How can I troubleshoot common Steering Gear Mechanism problems?
Basic troubleshooting includes checking for fluid leaks, inspecting the tie rods for damage, ensuring proper wheel alignment, and examining the steering components for wear. For more complex issues, it’s advisable to seek professional assistance from a qualified mechanic.