Question

The total mass of a shaft and other rotating parts is 2100 kg with a radius of inertia is 240 mm. The shaft, initially at rest is coupled to an electrical motor by one plate with two-contact surfaces with an inner and outer diameters of 180 and 280 mm respectively. The axial force on the coupling is 675 N and p = 0.34. The motor and its rotating parts have a total mass of 750 kg and a radius of inertia of 250 mm. A constant torque of 20 Nm is applied to the driving motor, initially rotating at 1420 rev/min when it engages with the shaft (initially at rest) and a period of slippage is observed until the motor and the shaft stabilize at the same constant speed. It is assumed that the shaft is well lubricated and rotating smoothly. Analyze the friction plate coupling and calculate: The frictional torque, assuming new plates are fitted: Tnew Nm. In the case of old used plates, the transmitted Torque is Tused Nm. In the case of used/worn plates, the normal force and the wear constant are such that: F1 = 21k(R – r) with k=pr. You are required to supply information to be used for the analysis of the pressure profile distribution. Analyse the problem and fill in the following table with values of the pressure at selected points on the contact surface Radial coordinate Pressure (Old/Used plate) Pused inner = N/m2 Pressure (New plate) N/m2 Rinner = 90 mm Pnew inner = R= 77 mm Pused = N/m2 Pnew = N/m2

Answer 1

solution: Given: e=0.34 Ri = gomma R2 = 140 mm HA 675N n=2 T=2X2 Xuxw [ro3-7,3 ro²-r 2 X 2 Xux w -2x 2 2 X 2 Xo? *0:34X675 1403-903 140²-go² = 306X175.21 = 53-61 Nim In case of old used plates I = axle CritR2) 2 = 2XLX0:34x 675(0.09 +0.14 2 - 52.785 Nim new We know that pressur ure cet any point plate is same 싸 675 NTCR-RST (1402-90 = 59340 N/?

classmate Data For old plate, PYEK Ez # W= 277 K (11-12)xn 675 2X2TI (140-90) ak-1.034 N mm :. Pat gömm 3 Px go=1.074 P -0.01193 mpa = 11935 Nm? Pat 77 mm PX 77 = 1.074 -P 13948 N/m2. : Radial coordinate pressure pressure old plate TH/m2) 11935 Need plete Edition) REgomm 9340 R=77mm 13948 9340