Development of Four wheel Steering Car to Reduce Turning Radius: Four Wheel Steering Mechanism Technology

ABSTRACT

Now a days with the increasing number of vehicles since the vehicles are with two wheel steering it is very difficult to take turn from a very short turns, and park the vehicle at very congested space. There should be a method to reduce the turning radius of the vehicle and also to make it possible to park a vehicle at congested space.

The purpose of the project is to develop a four wheel steering system to reduce the turning radius of the vehicle so that it can be maneuvered at short turns and can be easily parked in the congested space. This project report provides the appropriate solution for the stated problem. The mechanism that is used to connect the front wheel steering with the rare wheel steering is also explained in this report. The project report also explain about the different types of steering mechanisms and there applications in different conditions.

The different types of the chassis are also explained in the report and the most appropriate type of chassis for the project is also given in the context. The mechanical parts used for the fabrication of the project i.e. differential gear box, constant velocity (CV) shaft. Software based design of the four wheel steering mechanism is also explained in this report. The manufacturing process used for the fabrication of the project is also explained in this report.

The results obtained in the testing of the project are also explained in this report. Turning radius obtained in the two wheel steering system and obtained with the four wheel steering system are also compared. Comparison of the reduction of the turning radius in our work on four wheel steering and the previous work on four wheel steering is also given in the report.

Introduction:

A collection of links, joints and components that are combined together to make a turn of vehicle i.e. a car, jeep or a vessel i.e. ships and boats, is called steering. Steering helps the vehicle to make turn and to stabilize the vehicle after turning. The most common steering system used in the vehicles is two wheel steering system. The two wheel steering system can be front wheel or rare wheel steering. The front wheel steering is used in the vehicles used for the transportation purpose. Rare wheel steering system are most commonly used in the vehicles used for lifting heavy loads i.e. in the fork lifts, cranes etc.

Four wheel steering mechanism is type of steering in which all four wheels of the vehicle are turned with the single steering wheel. The four wheel steering system can be used for the reduction of the turning radius, to make crab motion, for the parallel parking of the vehicle and for the turning of vehicle about a single point i.e. zero turning. To minimize the turning radius the front wheel should be turned in opposite direction to the rare wheels. By turning both the front and rare wheels in opposite direction to each other the vehicle can turn easily in the confined space thus reduction in the turning radius can be achieved.

There are different methods for transmission of the power from front wheel steering to the rare wheel steering i.e. chain and sprockets, differential gear box, connecting shafts.

Problem Statement:

With a two wheel steering system it is very difficult to park the vehicle in very confined space where there is very less pace to turn the vehicle. To park a vehicle having length ‘L’ between two vehicles we usually require 1.7L of length of the vehicle to successfully park the vehicle.

In two wheel steering the stability of the vehicle is reduced when it is turning through a very short turns or to bypass a vehicle at high speed. The vehicle tends to slip from its back side when it is turned in very short turn at high speed. The vehicle requires large space to turn i.e. the turning radius of the vehicle is larger while turning through a U-Turn. This requires a large space for the vehicle to make a turn this may disturb the flow of traffic and may cause the accidents.

In two wheel steering system the rare wheels do not turn with the front wheels of the vehicle so due to this the efficiency of the steering is decreased because of the slippage of the rare wheels of the vehicle.

To overcome all of the above stated problem there should be a vehicle whose rare wheels should be turned along with the front wheels so that the vehicle can make easy turn in the confined space and the steering system should have its maximum efficiency. The most appropriate solution of all of these problems is the four wheel steering system. In the four wheel steering system the rear wheels of the vehicle will turn with the front wheels and the vehicle should have low turning radius.

We hope that the project will be an appropriate solution of the problems stated above. We hope that the four wheel steering system designed for our project would be effective in making a turn in very short space and the vehicle will have a less turning radius as compared to the two wheel steering system.

Working Mechanism:

Four wheel steering mechanism used in the project is based on the Ackerman Steering with rack and pinion assembly. There are two steering box having rack and pinion steering mechanism. One of the steering box is attached at the front wheels and the other steering box is attached with the rare wheels of the vehicle. Both of the steering boxes i.e. front and the rare are attached together via gear box having spur gear assembly. The steering wheel transfers the power to the gear box with the help of a spur gear attached at the end of steering wheel shaft. The gear box of steering will transfer the opposite motion on the front and the rare wheels due to the spur gear assembly i.e. if the front wheels are turned at right side the rare wheel will turn towards left side.(four wheel steering mechanism)