Chemical Engineering - Apllied Mechanics

Transmissions - Part n5

Divided by topic

MECHANICAL TRANSMISSIONS A. Vania Politecnico di Milano, Dept. of Mechanical Engineering , Milan, Italy APPLIED MECHANICS -Prof. A. VANIA 2 GEAR TRANSMISSION TRANSMISSION OF ROTARY MOTION AND TORQUE FROM A DRIVE SHAFT TO A DRIVEN PARALLEL SHAFT Input data  : transmission ratio I : span 1 1 2 2RR  =  2 1 12 R R   ==  12 I R R=+ 1 2 R R = APPLIED MECHANICS -Prof. A. VANIA 3 TOOTH PROFILE pressure angle: a : addendum d : dedendum evolvent profile 20   base pitchR R cos( )  = APPLIED MECHANICS -Prof. A. VANIA 4 GEAR TRANSMISSION line of action Transmitted torque The contact point between two engaged teeth moves from the base to the top of a tooth profile . The contact point is always on the line of action . The normal force transmitted from the drive gear to the driven gear always acts along the line of action .base M N R = APPLIED MECHANICS -Prof. A. VANIA 5 JOURNAL BEARINGS JOURNAL ROLLER BEARINGS OIL -FILM JOURNAL BEARINGS ball roller bearing cylindrical roller bearing APPLIED MECHANICS -Prof. A. VANIA 6 HELICAL GEARS JB: journal bearing TB: thrust bearing JB JB JB JB TB TB The engaged teeth generate an axial force Thrust roller bearings oil -film thrust bearing