SPUR GEAR Gear design based on Lewis and

SPUR GEAR Gear design based on Lewis and Buckingham equation

Step 1: selection of material for pinion and gear Suitable material is not given, select the material • If both are of same material, then design is based on pinion

Step 2: Calculation of z 1 and z 2 • If z 1 is not given, then take z 1 ≥ 17 o i – gear ratio o No of tooth on pinion(z 1) and gear(z 2) respectively

Step 3: Calculation of tangential load on tooth (Ft): Refer psg data book pg. 8. 50 • 1 HP = 746 watts • Mean velocity (vm), in m/s Vm = pitch circle diameter (d) = m z module (m) in “mm” Number of tooth (z)

Step 4: Calculation of initial dynamic load (Fd): Refer psg data book pg. 8. 50 Take Cv- based on Vm

Step 5: calculation of beam strength (Fs): • • Refer psg data book pg. 8. 50 Face width – b (initially take b = 10 m) where, m is the module Design bending stress If not given, refer data book pg. 8. 18 – equation 7. 1 or refer DB pg. no – 8. 5, table 7 • Form factor – y ( refer 8. 50)

Step 6: calculation of module (m): Equate, Fs ≥ Fd Find the module. Select nearest standard module******* (refer DB pg. 8. 2 – table 1)

Step 7: calculation of b, d and v: • b= 10 m in mm • d= z m in mm • Velocity, m/s

Step 8: recalculation of beam strength (Fs): • Substitute standard module value

step 9: calculation of accurate dynamic load (Fd): Refer psg data book pg. 8. 51 Ft , refer step 3 C, deformation factor Refer DB pg. 8. 53 - table 41 C in ‘mm’ v in ‘mm/s’ b in ‘mm’

Step 10: check for beam strength Refer psg data book pg. 8. 51 Fs ≥ Fd

Step 11: calculation of maximum wear load(Fw): Refer psg data book pg. 8. 51 F w = d 1 Q k b K – refer 8. 51 , refer DB pg. 8. 16 E- refer DB pg. 8. 14 - table 9

Step 12: check for wear: • Fw ≥ Fd , design is safe • The gear tooth has adequate wear capacity and tooth will not wear out.

Step 13: calculation of basics dimensions of pinion and gear:

problem Design a spur gear drive required to transmit 45 Kw at pinion speed of 800 r. p. m. The velocity is 3. 5 : 1. The teeth are 20 o full depth involute with 18 teeth on the pinion. Both the pinion and gear are made of steel with a maximum safe static stress of 180 N/mm 2. Assume medium shock conditions.