What is rack and pinion steering mechanism

What Is Rack And Pinion Steering Mechanism? | How Rack And Pinion Steering System Works?
STEERING SYSTEM | WORKING and COMPONENTS
Working of Four Wheel Steering System in Hindi | Advantages, and Disadvantages of 4-Wheel Steering
How Power Steering System Works?

1. What Is Rack And Pinion Steering
Mechanism? | How Rack And Pinion
Steering System Works?

The Rack and Pinion is a type of steering mechanism with a pair of gears which convert the rotary motion into the
linear motion. This system consists of a circular gear called pinion engages with the teeth on the linear gear shaft
called the rack. The rotary motion applied to the pinion causes it to turn while it moves rack sideways.
This mechanism is simple and driver-friendly. It is the most effective and hence; widely used steering system by car
manufacturers around the world. It is universally accepted that it is the best system to use. The mechanism consists
of a pinion at the end of the steering column that meshes with the rack. The pinion is fixed to the steering column at
its end. It meshes with the rack which moves either to the left or the right side depending upon the movement of the
pinion. In this steering mechanism, rack acts as the center section of the three piece rod. The rack has ball joints at
each end that allow the up & down movement of the wheels. Also, there is a spring loaded pad underside the rack
which reduces the backlash between the gears. The rack engages with the pinion mounted on the steering shaft.
Furthermore, the ball joints further connect to the stub axles thru' tie rods. The rotary motion of the steering wheel
directly conveys to the wheels thru' the sideways movement of the rack. In case of most of the steering gears, on a
right-hand drive car, the far-side wheel is steered directly while the near side wheel is driven thru’ the linkage. In case
of light sports cars, this type of steering gear has significantly lower gear reduction. The rack always connects to
either side of the steering wheel arms. The moving rack moves the wheel in either one or other way. The movements
are usually part of a simple mechanism. The rotation of the steering shaft, thru' either hand or by a motor, converts
rotary motion into linear motion. The load of the rack is usually minimal. However, it requires some torque because
the gear ratio is low.

STEERING SYSTEM | WORKING and
COMPONENTS

The steering system converts the rotation of the steering wheel into a swivelling movement of the road wheels in such
a way that the steering-wheel rim turns a long way to move the road wheels a short way. The system allows a driver
to use only light forces to steer a heavy car. The rim of a 15 in. (380 mm) diameter steering wheel moving four turns
from full left lock to full right lock travels nearly 16 ft (5 m), while the edge of a road wheel moves a distance of only
slightly more than 12 in. (300 mm). If the driver swivelled the road wheel directly, he or she would have to push nearly
16 times as hard. The steering effort passes to the wheels through a system of pivoted joints. These are designed to
allow the wheels to move up and down with the suspension without changing the steering angle. They also ensure
that when cornering, the inner front wheel - which has to travel round a tighter curve than the outer one - becomes
more sharply angled. The joints must be adjusted very precisely, and even a little looseness in them makes the
steering dangerously sloppy and inaccurate. There are two steering systems in common use - the rack and pinion
and the steering box. On large cars, either system may be power assisted to reduce further the effort needed to move
it, especially when the car is moving slowly.

2. Working of Four Wheel Steering System in
Hindi | Advantages and Disadvantages of 4-
Wheel Steering

A four-wheel steering system (or all wheel steering) allows the driver to turn the rear wheels left or right along with the
front wheels. Do not confuse a four-wheel steering system with a four-wheel drive vehicle because they’re two
different things. Four-wheel drive simply means that all four wheels are getting power from the engine. A four-wheel
steering system means you can actually turn all four wheels with the steering wheel. Here we are going to focus on
the pros and cons of the rear wheel steering system. The main purpose of all-wheel steering is to increase the agility
and stability of a vehicle. At low speeds (usually under 30 or 40 MPH), the rear wheels turn slightly in the opposite
direction as the front wheels. This is known as “counter-phase steering” and allows the vehicle to have a smaller
turning radius for better agility. At higher speeds (usually over 30 or 40 MPH), the rear wheel turn slightly in the same
direction as the front wheels. This is known as “in-phase steering and allows the vehicle to be more stable during high
speed corning. The vehicle actually leans less in and out of a corner since both axles share the turning forces instead
of just the front. Top 5 Advantages of Four-Wheel Steering :
1) Smaller Turning Radius A four-wheel steering system gives you the ability to make tighter turns in a smaller radius
because the rear wheels are able to turn in a different direction than the front wheels. This makes it easier for you to
maneuver your vehicle in a tight parking, parallel park, or complete u-turns in areas some cars can’t.
2) Better Stability If you want a smooth driving experience, then it always helps to have stability in your vehicle. A
four-wheel steering system makes it easier for you to control your vehicle and keep it stable, especially when you’re
traveling at higher speeds with lots of turns.
3) Quicker Steering Response There is nothing worse than a steering wheel that doesn’t respond immediately to the
turns that you make with it. A four-wheel steering system gives your steering wheel a much faster response than a
standard two-wheel steering system. You’ll be able to be more precise in the direction that you’re traveling in.
4) Faster Lane Changes If you’re someone who regularly drives on the freeway and you constantly find yourself
changing lanes or passing other vehicles, then a four-wheel steering system will help you do this fast and efficiently.
You’ll be able to move into and out of another lane quicker and smoother than most other vehicles.
5) Better Safety Not every car “rides on rails” like a Mazda Miata or Chevy Corvette. If you ever find yourself go too
fast for a corner that you misjudged, rear-wheel steering will cause less body roll and may just save you from going
off the road or into another vehicle. Top 2 Disadvantages of Four-Wheel Steering :
1) Higher Risk of Malfunction A four-wheel steering system is comprised of many electronic components and parts.
All it would take is for one component to malfunction and then the entire system would malfunction. As a result, you
will likely need to perform additional maintenance on a four-wheel steering system just to keep it operational for use.
This not only means spending more time and money on it, but it also means that you’re more at risk of experiencing
problems with the system as you’re driving too.
2) Pricey A car that has a four-wheel steering system is going to cost a lot more money than a car with just a two-
wheel steering system. This is due to the four-wheel steering system being more expensive to manufacture and
develop, since it contains more sophisticated components than a two-wheel steering system. All-wheel steering is
often a standard feature with many high end sports cars but many other vehicles, it’s simply an optional feature so
you at least have the choice of deciding whether the extra cost is worth it.

3. How Power Steering System Works?

A steering system of an automobile is an integral part of vehicle dynamics of a vehicle in which a series of
mechanical components having certain important angles comes together to steer the front wheels of the vehicle
according to input provided by the driver through steering wheel. The power steering system is the advanced steering
system in which the effort required to steer the front wheels of the vehicle side to side is reduced by using
intermediate electric or hydraulic devices that multiplies the force applied by the driver through steering wheel in order
to achieve smooth and quick directional change of the vehicle. Important Components of Power Steering System-
1. Steering mechanism- Usually rack and pinion steering mechanism is used in power steering in which the rotational
motion of the steering wheel is converted into the transverse motion of the wheels by a set of constantly meshed
worm gears called rack that provide transverse motion and a pinion that provides rotational motion.
2. Linkages – They are the mechanical constraints that provide relative motion between 2 components, the type of
linkages used in power steering is the tie-roads that connects the rack to the knuckle of the wheel in order to transfer
the transverse motion of the rack to the wheels.
3. Power device- A force multiplying device (either hydraulic or hybrid or electric) is used to multiply the steering
wheel force in order to reduce steering efforts. This device is attached with the pinion of the rack and pinion
mechanism.
4. Steering wheel- A round steering wheel is used inside a cockpit (operated by the driver) that provides the
rotational steering input to the further steering devices in order to steer the vehicle. Working of Power Steering
System:
1. Hydraulic Power Steering System In this type of power steering system, the hydraulic force is used to multiply the
steering input force in order to smoothen the steering of the front wheels, this hydraulic force is generated by a series
of components that includes hydraulic cylinder, rotator hydraulic pump, hydraulic lines, highly compressed hydraulic
fluid and a coupling mechanism that can couple this hydraulic system with rack of the steering system. When the
driver provides input by rotating the steering wheel, the hydraulic pump driven by the engine starts pumping the
highly compressed hydraulic fluid through lines. The hydraulic pressure produced by the pump enters the hydraulic
cylinder which in turn applies pressure over the cylinder’s piston. The piston which is under high pressure starts
moving from one end to the another which in turn pushes the further fluid through lines, with this movement of piston
the input force applied by the driver is multiplied several times. This high pressure fluid sent by the hydraulic cylinder
then applies the pressure to the attached pinion through the coupling mechanism which in turn applies high force to
the rack gear and the steering action in the front wheels takes place.
2. Hybrid or Semi Hydraulic Power Steering System In this type of power steering system the hydraulic pump driven
by the engine from the hydraulic power steering system is replaced with electric pump which makes it more reliable,
this is the only modification made rest the working of this system is same as the hydraulic power steering system
mentioned above.
3. Electric Power Steering System This system is latest of all the steering system mentioned above in this type of
steering system as we have already discussed the force multiplication is the function of the electric motor instead of
hydraulic fluid and the working of this system is as follows- When the driver gives input through the steering wheel the
electronic sensors attached to the steering column reads the input and sent them to the electric control unit of the
vehicle. The ECU of the vehicle analyses these inputs and sent the voltage signal to the electric motor placed at the
end of the steering column whose gear is in constant mesh with the pinion gear. Due to these voltage signals sent by
the ECU the motor which is driven by the battery of the vehicle starts and provides the particular torque according to
the value of the voltage signals received After the motor starts the gear which is in constant mesh with the pinion gear
starts transmitting the multiplied torque to the pinion gear which in turn applies this torque to the rack through which it
is attached. With this torque applied by the pinion over rack , rack moves which in turn steer the front wheels (with the
help of the tie rods attached) as per the requirement.