The work of friction is proportional to the product of normal pressure (p) and sliding velocity (V). The basic principle in designing machine parts that are subjected to wear due to sliding friction is that the normal wear is proportional to the work of friction.Considering Uniform Axial Wear (Used for worn - out clutches) .Where, r = mean radius of the friction surface Total frictional torque acting on the friction surface or on the clutch, Where, W = Axial thrust with which the frictional surfaces are held together. Considering Uniform Pressure (Used for new clutches).R 1 and r 2 = External and internal radius of friction facesįrictional force on the ring acting tangentially at radius, xį x = µp.2px.dx Frictional Torque acting on the ring, P = intensity of axial pressure with which the contact surface are held together, Let, T = torque transmitted by the clutch The multiple disc clutches are extensively used in motor cars, machine tools etc. The inside discs are fastened to the driven shaft to permit axial motion. A multiple disc clutch may be used when a large torque is to be transmitted.If the torque due to this frictional force exceeds the torque to be transmitted, then no slipping takes place and the power is transmitted from the driving shaft to the driven shaft. The axial pressure exerted by the spring provides a frictional force in the circumferential direction when the relative motion between the driving and driven members tends to take place. It is mounted on the hub which is free to move axially along the splines of the driven shaft. A single disc or plate clucth whose both sides are faced with a frictional material.It should have high resistance to wear and scoring.It should have the ability to with no space stand high temperature caused by slippage.
It should not be affected by moisture and oil.It should have a high and uniform coefficient of friction.The material used for the friction clutch have following characteristic : In automobiles, friction clutch is used to connect the engine to the drive shaft. A friction clutch has its principal application in the transmission of power of shafts and machines which must be started and stopped frequently.This type of clutch is occasionally used where the clutch must be engaged and disengaged while in motion. The spiral jaw may be left handed or right hand, because power transmitted by them is in one direction only.This type of clutch will transmit power in either direction of rotation. A square jaw type is used where engagement and disengagement in motion and under load is not necessary.
The simplest type of a positive clutch is a jaw clutch.
0 kommentar(er)
