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Understanding the working of shock absorber

Thinking of how automobile vehicles gain balance and control when driving on rough ground, it’s possible you first think of its shock absorber. Shock absorbers are used in various applications in our daily life not just in automobiles. However, in vehicles, it reduces the effect of traveling over rough ground, its improved quality ride, and better vehicle handling.

Today you’ll get to know the definition, functions, applications, components, diagram, types, and working of a shock absorber. You’ll also get to know its advantages and disadvantages as well as symptoms of a bad or failing shock absorber.

shock absorber

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What is a shock absorber?

A shock absorber is a mechanical or hydraulic device designed to absorb and damp shock impulses. This is achieved by converting the kinetic energy of the shock into another form of energy (typically heat) which is then dissipated.

A rubber shock absorber is the most common type, due to its durable high elasticity, ability to eliminate vibration, shock, and sound insulation. It has the ability to form a required shape and satisfy the requirements of stiffness and strength. The rubber vibration absorber has some certain damping function such as the ability to absorb mechanical energy, especially high-frequency oscillation energy.

In vehicles, shock absorbers reduce the effect of rough ground, leading to a bad driving experience. It improves riding quality and vehicle handling. Shock absorbers offer a great purpose of limiting excessive suspension movement, with the intended sole purpose of damping spring oscillations. Valving of oil and gases are used in such an absorber to remove excess energy from the springs. This spring rate or strength is determined by vehicle manufacturers based on the weight of the vehicle.

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Applications of shock absorber

Shock absorbers can be seen in many different applications in our everyday life as they support various activities humans can encounter. They are used for highways, bridges, cars, bikes, bicycles, and buildings to absorb the impact of the bumps, earthquakes, and high winds. However, different applications require different types of shock absorber, which can be made of different materials. i.e. a rubber shock absorber cannot be used on a vehicle and a cylindrical shock absorber cannot be used on a highway. The various types of absorber require a specific shape and design to fit its intended tasks.

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Functions of shock absorbers

Below are the functions of shock absorber in their various applications:

  • The primary function of a shock absorber is to absorb or dampen the compression and rebound of the springs and suspension.
  • It helps to control unwanted and excess spring motion
  • It keeps tires in contact with the road at all times
  • Shock absorber ensures the safest control and quicker braking response of your car.

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Components of a shock absorber

Since shock absorbers are used in various applications, they’re different in design and operation. The truth is their parts remain similar. Below are the major components of a shock absorber in vehicles:

Mount:

this shock absorber part help to secure shocks to the vehicle body and suspension. It consists of an upper and lower mount of the same design, containing a surface hollow part that allows bushing and bolt to be inserted.

Bushing:

The bush is located on the mountings, usually made of rubber or urethane. This bushing absorbs vibrations and has separate metal parts to prevent noise and wear. Bushings are among shock absorber components that can be replaced.

Coil spring:

Not all shock absorber features a coil spring in its parts. It’s commonly known as a coil-over-shock absorber or spring coil shock absorber. Absorber with coil spring looks like a suspension strut, one can easily mistake them for each other.

Piston and piston rod:

Shock absorbers piston contains openings or valves that allow its part to revolve around the movement of oil through passageways. The piston rod guides the piston inside the shock absorber cylinder.

Cylinder:

This is a cylindrical tube that acts as the body of a shock absorber. It consists of compression oil and a piston that moves inside it.

Bolts:

Bolts are fasteners used to hold a shock absorber to a vehicle’s body on one end and suspension at the other end. These bolts must be torqued to the right torque value so that the absorber won’t lose during operation.

Some other small parts of car shock absorber include:

Oil seal – the oil seal help to prevent the oil inside the shock absorber tube from leaking out while working. It also prevents contamination from entering the tube.

Oil guide – this is an oil passage to ensures the smooth working of the absorber.

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Rod guide – the rod guide gives the piston rod smooth movement.

Nitrogen gas and gas chamber – this is contained in a chamber within the compression chamber or cylinder. It prevents the oil from forming bubbles.

Washer and plates – these are a spacer that forms an important part of the shock absorber parts.

Diagram of a car shock absorber:

shock absorber diagram

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Types of shock absorber:

The application of shock absorbers is very many, various types of vehicles and suspension designs require a specific type. However, no matter the application, all types of shock absorbers fall under these three types:

Conventional telescopic shock absorbers:

The conventional telescopic types of shock absorbers are the most common type that can be found both on front and rear suspension systems. it’s relatively inexpensive and It’s often replaced rather than repairing.

Strut type shock absorbers:

These types of shock absorbers are typically built strong to cope with greater loads and forces. They do the same job as the normal shock absorbers, but it replaces part of the suspension system. struct types of shock absorbers are commonly seen on the front and rear of small and medium cars, but now trending on larger cars.

These types of shock absorbers are further divided into two; sealed and repairable units. Just as they are named, sealed units are designed to be fully replaced, whereas the repairable struts are be fitted with replacement strut cartridges.

Spring seat shock absorbers:

These types of shock absorbers combine the characteristics of both telescopic and strut type of absorbers. Like structs, a spring seat is a suspension unit and damping device in a single unit, but it’s not designed to be subject to high side loads like the structs. This system uses the same components as the conventional type and the spring seat type is sealed requiring full replacement.

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Working principle

The working of a shock absorber is less complex, it can be easily understood if we know about the law of conservation of energy. This law state that energy cannot be created or destroyed, it can only change forms.

So, let us learn about potential and kinetic energy in brief. Potential energy is stored energy, and kinetic energy is energy in motion. A shock absorber uses this principle in its working. For instance, when your car hit any bump or dip in a road, your vehicle’s suspension and springs move so that the tire can stay in contact with the road and absorb the energy. In this case, the shock absorber dampens the movement of the spring as it converts the spring’s kinetic energy into thermal (heat) energy. This thermal energy then degenerates in hydraulic fluid.

A shock is an oil-filled cylinder, which allows the suspension to move, that’s a piston moves up and down through the oil-filled cylinder. This up and down movement of the piston forces small amounts of fluid through some tiny holes in the piston head.

Due to the fact that a small amount of fluid is forced out, the suspension’s movement slows down. It dampens the compression and rebound the springs. The faster a shock absorber’s springs move, the more resistance the absorber offers. This makes the system a velocity-sensitive.

Watch the video to learn more about how a shock absorber works:

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Advantages and disadvantages of a shock absorber

Advantages:

Below are the benefits of shock absorber:

  • it’s available in various shapes and different strengths and hardness, with outstanding elasticity.
  • Deformation of a shock absorber is relatively large as no matter in tension, compression, shearing, and changing force.
  • The natural frequency of the vibration isolation system is lower but has a higher damping effect.
  • Easy to maintain without sliding
  • The modulus of elasticity in a shock absorber is much smaller than that of metal, and large elastic deformation can occur.
  • The shock absorption effect is good.
  • Convenient installation and disassembly.

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Disadvantages:

Despite the great advantages of a shock absorber some limitations still occur. below are the disadvantages of a shock absorber in a car:

  • It has a low ability to resist environmental pollution and temperature change.
  • Its life is short
  • A shock absorber finds it difficult to achieve natural frequency below 5Hz
  • Some types cannot be repaired but have to be replaced.

Symptoms of bad and failing shock absorber

Below are symptoms or signs of a bad and failing shock absorber in a car:

  • Vibrations while driving
  • Swerving or nose-diving while braking
  • Braking takes time to actuate
  • Uneven tire wear
  • Leaking fluid
  • A cracked bushing at an attachment point

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In conclusion, shock absorbers are great devices that are employed in different applications to absorb or damp shock impulses. In this article, we’ve seen the definition, functions, applications, components, types, and working of a shock absorber. We also saw its advantages and disadvantages as well as bad symptoms that could show the system is faulty.

That’s for this article, I hope you enjoyed the reading, if so, kindly comment, share, and recommend this site to other technical students. Thanks!

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