圆上泽文大学 Worms and worm Gears Worms(蜗杆)and worm gears are used to transmit motion and power between nonparallel,nonintersecting axes. Worm is similar to a screw thread. having one or a few teeth Helix angle is very large. Worm mates with a special gear called a worm gear or worm wheel Analogous to a nut being advanced by the thread of the worm. Their axes are typically at 90 degrees to one another. © 上海充廷大学 Worms and worm Gears The worm set can give very large gear ratios(up to about 360:1)in a compact package >Because of the small number of teeth on the worm. If the lead angle of the worm is small enough ( about 6 degree)the worm set can be self-locking In other words,it cannot be back-driven from the worm gear,i.e.it will hold a load. 88  Worms （蜗杆） and worm gears are used to transmit motion and power between nonparallel, nonintersecting axes. Worms and worm Gears  Worm is similar to a screw thread, having one or a few teeth  Helix angle is very large.  Worm mates with a special gear called a worm gear or worm wheel  Analogous to a nut being advanced by the thread of the worm.  Their axes are typically at 90 degrees to one another.  The worm set can give very large gear ratios (up to about 360:1) in a compact package  Because of the small number of teeth on the worm.  If the lead angle of the worm is small enough (< about 6 degree) the worm set can be self-locking  In other words, it cannot be back-driven from the worm gear, i.e. it will hold a load. Worms and worm Gears