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Construction and Working Of Hydraulic Shock Absorber

Introduction to Shock Absorber

A shock absorber or (Shock Damper ) is a mechanical or hydraulic device designed to absorb and damp shock impulses. It does this by converting the kinetic energy of the shock into another form of energy (typically heat) which is then dissipated. A shock absorber is a type of dashpot.

Pneumatic and hydraulic shock absorbers are used in conjunction with cushions and springs. An automobile shock absorber contains spring-loaded check valves and orifices to control the flow of oil through an internal piston (see below).

One design consideration, when designing or choosing a shock absorber, is where that energy will go. In most shock absorbers, energy is converted to heat inside the viscous fluid. In hydraulic cylinders, the hydraulic fluid heats up, while in air cylinders, the hot air is usually exhausted to the atmosphere. In other types of shock absorbers, such as electromagnetic types, the dissipated energy can be stored and used later. In general terms, shock absorbers help cushion vehicles on uneven roads.

Construction :

1. The assembly consist of sheet metal body which cover with piston and cylinder.
2. Cylinder ‘C’ houses valve ‘A’ and Valve ‘B’.
3. Cylinder’C’ is surrounded by outer tube ‘D’.
4. There is annular space between cylinder ‘C’ and Cylinder ‘D’.
5. Valve ‘A’ and ‘B’ have small orifice passing through it.
6. The annular space is half field with fluid whereas inner cylinder completely filled.
7. Cylinder ‘C’ is closed on top with head ‘H’ and small Gland ‘J’ is provided to return any fluid back to reservoir.
8. Upper eye ‘F’ is connected to vehicle frame and lower eye ‘E’ is connected to axle.

Working

When vehicle come across a bump :

When vehicle come across a bump the lower eye would move up and thereby fluid will passed from lower eye side of valve ‘A’ to its upper side.
Volume of space Above Valve ‘A’ is less by volume of rod.
Due to this fluid will exert pressure on valve ‘B’ and go to underside of valve ‘B’ into annular space.
Passing of fluid through valve opening provide damping action.

When Vehicle Encounter A Pit :

Similarly vehicle encounter a pit there is downward motion of lower eye .
Cylinder ‘C’ and ‘D’ moves downward.
Due to this above ‘A’ is compressed and it move downward below valve ‘A’ and also in annular space through valve ‘B’ damping the Shock.

Post Submitted By:
Vrushabh Dhatrak,
K B P Poly. Kopergaon

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