6 power steering

POWER STEERING

INTRODUCTION• In automobiles, power steering (also known as

power assisted steering (PAS) or steering assist system).

• It helps drivers to steer easily by reducing the steering effort of the steering wheel.

• Hydraulic or electric actuators added to control the energy to the steering mechanism, so the driver needs to provide only less effort while driving.

Power Steering Systems

• Power assist – (power steering) – uses hydraulic or electric power to help the driver applied steering force.

• In the power steering system, a continuously operating pump provides hydraulic pressure when needed.

• At the steering wheel is turned, valves are operated to admit this hydraulic pressure to a cylinder and transmitted to the steering linkage.

• Both steering system have– Steering wheel.– Steering gear box.– Steering linkages.

Types of power steering system

1. HYDRAULIC POWER STEERING.

Integral power steering. Linkage power steering.

2. ELECTRIC 0R ELECTRONIC POWER STEERING.

HYDRAULIC POWER STEERING

• Hydraulic power steering uses high pressure fluids for assisting the steering movement.

• It uses a plunger type arrangement for its working.

• When the driver turns the steering wheel, it opens up the flow or pressurized fluid in such a way that helps to turns the wheels in the required direction.

1.Integral type power steering

• It consists of a spool valve, rotary valve and a torsion bar.

• The torsion bar is attached to the end of the worm shaft.

• When the steering wheel is turned, the torsion bar twists.

• This moves the spool slightly, opening passages which move high pressure fluid to the side of the piston where hydraulic assist is required.

• When there is no power-assist action, the spool valve is in the neutral position.

• The integral type is more widely used.

Torsion Bar

Torsion Bar

torsion bar in steering

2.Linkage type power steering

• In this type of steering the power system is attached between the frame of the vehicle and the steering linkage.

• Usually it must be installed at the factory as the vehicle is built.

• The linkage type is widely used on trucks.

ELECTRIC 0R ELECTRONIC POWER STEERING

• Electric power steering works with the help of an Electric Motor and a control unit which has some sensors.

• The motor runs on battery and will use electric power to assist the movement of steering when the driver turns the wheel.

Working principle of electronic power steering

ELECTRONIC STEERING CONTROL UNIT

Hydraulic Power Steering V/S Electric Power Steering

1. Hydraulic Power Steering System is complicated compared with Electric Power Steering.

2. Hydraulic Power Steering System usually weighs more than Electric Power Steering.

3. Hydraulic Power Steering uses hydraulic fluids for operation whereas there is no such fluid needed for Electric Power Steering, thus Electric Power Steering needs less maintenance compared to hydraulic power steering.

4. Electric Power Steering gives better response at different speeds as compared to Hydraulic Power Steering.

5. Electric Power Steering is less prone to problems and faults and are more durable as compared to Hydraulic power steering.

6. Hydraulic power steering extracts power from engine, so it reduces the fuel mileage of the engine. Electric power steering consumes power from battery which is also charged by engine, but it consumes less power compared to Hydraulic power steering. So a car having Electric power steering will give more mileage than one with Hydraulic power steering.