Dashpots
utilizes viscous friction for resisting motion. Dashpots consist of piston
which moves through a viscous fluid in conjunction with a spring, in shock
absorbers. The damping force is proportional to the velocity of the
movement. During motion this damping force reacts in the opposite direction.
This movement in the opposite direction the damping force so created
counteracts the motion and absorbs energy. There are two specifications that
characterized dashpots.
Dashpots Specifications
These specifications are:
- The stroke and the damping coefficient.
- Linear displacement of the dashpot is measured by the stroke whereas
damping force per velocity is measured by the damping coefficient.
- Dash pot is commonly used as shock absorber in various vehicles.
- It is also used in door closer device.
In a dashpot, velocity produced is always linearly proportional to the
force applied. Symbolically it can be represented as:
f(t)= µv(t)
µ= dashpot impedance
f(t)= is the applied force at time t
v= the velocity
Purpose
Served by Dashpots
Purposes served by the dashpots are:
- It keeps the piston steady by preventing the piston following air
fluctuations at low engine speed.
- Prevents the piston rising in unison with the opening of the
throttle.
Types of Dashpots
There are two types of dashpots that are used commonly.
Rotary Dashpots
Rotary dashpots consist of damping coefficient(force per velocity) in
torque per angular velocity.
Linear Dashpots
Specifications of the linear dashpots consist of stroke and damping
coefficient where stroke measures the amount of linear displacement and
damping coefficient is the measure of force per velocity.
