Transmissions Part n5

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MECHANICAL TRANSMISSIONS A. Vania Politecnico di Milano, Dept. of Mechanical Engineering, Milan, Italy APPLIED MECHANICS - Prof. A. VANIA 2GEAR TRANSMISSION TRANSMISSION OF ROTARY MOTION AND TORQUE FROM A DRIVE SHAFT TO A DRIVEN PARALLEL SHAFT 1 1 2 2RR =  2 1 12 R R == 12I R R=+ 1 2 R R = Input data  : transmission ratio I : span APPLIED MECHANICS - Prof. A. VANIA 3TOOTH PROFILE pressure angle: 20  base pitchR R cos( ) = a : addendum d : dedendum evolvent profile APPLIED MECHANICS - Prof. A. VANIA 4GEAR TRANSMISSION line of action baseM N R= 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. APPLIED MECHANICS - Prof. A. VANIA 5JOURNAL BEARINGS JOURNAL ROLLER BEARINGS OIL-FILM JOURNAL BEARINGS ball roller bearing cylindrical roller bearing