2. Friction drives 2.1. Basic definitions and classification The frictional gear (Fig. 2.1) consists of two rollers 1 and 2, which are pressed one to another by the force Fr. The rotation from one roll to the another is transmitted by the friction force Ff....
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2. Friction drives 2.1. Basic definitions and classification The frictional gear (Fig. 2.1) consists of two rollers 1 and 2, which are pressed one to another by the force Fr. The rotation from one roll to the another is transmitted by the friction force Ff. Friction gears are used for power transmission up to 20 kW. The value of the efficiency factor lies in the range of 0,90 ... 0,95. Because of limitations in overall dimensions, the gear ratio is recommended to take u ≤ 10. Fig. 2.1. Scheme of friction gear Steel ШХ15 with heat treatment of hardness 50 ... 55 HRC, alloyed steel 40Х, 40ХН with hardening, cast iron, nonmetallic materials - textolite, fibre, wood, leather and rubber are most often used as the materials for friction rollers. Fig. 2.2. Schemes of the roller friction transmission construction The rollers construction is largely determined by materials. Metal rollers are made as a disk shape (Fig. 2.2, a), metal rollers of small diameters make a solid with a shaft (Fig. 1.6
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