Hydraulic steering

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Hydraulic steering working

1. How it works Hydraulic Steering

2. Projects members 116 Azeem Waqar 123 Tariq Aziz 152 Saud Zaman

3. introduction Power Steering's are also known as POWER ASSISTED STEERING(PAS). Power steering’s can be divided in Electronic Steering and Hydraulic steering. Power steering helps drivers to reduce the steering effort on vehicle by using an external power. It considerably helps in slow moment and when the vehicle is stop. Also power steering provide feedback of forces on the front wheels interacting with road which is known as Road feel.

4. history The first power steering system was apparently installed in 1876 by Fitts . But necessary information about him is not present. In 1926 Engineer Francis W.Davis of the truck division of Pierce Arrow invented and demonstrated the first practical power steering. In world war-II it gain much importance due to the need of easier steering for armored cars and heavy cars of British and US Army. 1951 first commercial passenger car with power steering was introduced in market.

5. Components of steering Steering Wheel Steering Shaft Steering cam Steering gear Pitman Arm Shaft Drag link Tie Rod

6. Components Of Hydraulic System The Hydraulic steering contains the following parts Reservoir Pump Relief valve Control valve Power Cylinder

7. Functions of Hydraulic System Components Reservoir=It supplies the fluid. Pump=Driven by the Engine through belt It transfer the fluid from reservoir to relief valve and than to the control valve under pressure. Relief valve=It provides an escape to the fluid back to the reservoir Control valve=It directs the fluid to the Power Cylinder. It is also called heart of hydraulic system. Power cylinder=It converts Hydraulic System into m echanical force, which in turn activates Pitman Arm Shaft and lever.

8. Principal of working The Hydraulic Steering works on the principal of pressure differences. The difference in pressure affects the position of piston in power supply which in turn affects pitman arm shaft and lever. Power Cylinder

9. Working Mechanism The schematic diagram is shown The Reservoir supply fluid to Pump The Pump transfer it to relief with p ressure, than to control valve The control valve directs the fluid t o power cylinder and than to reservoir. When the steering wheel is turned it rotates the steering shaft and steering cam both. Steering cam also do up and down moment along with rotation

10. Working Mechanism The up and down moment of cam Control the control valve through Control valve linkage It pull or push the spool to one dir- -ection and as a result fluid start f lowing to the power cylinder in one direction as a result pressure difference is created. Due to this the piston moves and with its movement it also move pitman arm lever which is connected through rod. And wheel is moved to the desire direction. It this stage the pump still drawn fluid, which is transfer back to the reservoir with the help of relief valve.

11. Constant steering and neutralization When the pitman arm lever moves it also moves the cam due to which The spring is compressed in one dir- -ection which applies opposite pressure to the pressure of fluid until it equalize,due to which the to which the lever is held stationary . This phenomena help in constant steering. And when the driver leave the torque on the steering due to t he spring compression, it forces the lever and piston to came back to its original position, so after steering the wheels and steering disk come back to its original position automatically. This is called steering neutralization.

12. Road jerk Like the shock absorbers the hydraulic system also help in steering shocks absorbing. Due to w hich the losing control of heavy vehicle stops. When the any tire is subjected to road jerk this jerk is transferred to pitman arm lever. Pitman lever activates the cam which in turn activates the control valve, the control valve creates the small pressure difference which is neutralized by the spring compression attached to the cam This neutralization is actually the jerk absorbing. And in this phenomena the road jerk is absorbed.

13. Uses in modern age HPS system finds its applications in … Small vehicles . Heavy vehicles as trucks transporting heavy loads. In small and large Boats. Large military vehicles

14. Advantages HPS has no steering wheel torques as compared to mechanical system. In HPS no freezing of steering is caused by dried up grease or corrosion in steering tube of vehicle . It can be used in big vehicle where electronic system fails. It absorbs major part of road shock as compared to mechanical system.

15. Disadvantages HPS weights usually more than electric system. HPS carry fluid for transmission as compared to electric system so need more maintenance. Electric system give better response as compared to Hydraulic power steering at different speed. HPS has more prone and faults and less durable as compare to electric steering system. Electric system will give more mileage with one having hydraulic steering system.

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