Hypoid gear, as the main part of mechanical transmission system, is widely used in automobile, engineering machinery, mechatronics products and other staggered shaft transmission because of its large coincidence degree, stable transmission, strong bearing capacity and flexible spatial layout. The application of this type of transmission with large reduction ratio is of great significance to improve the power density of mechanical power transmission system.
Spiral bevel gears usually refer to two types: one is spiral bevel gears with small and large wheel axes crossed and no offset distance. The other is the hypoid gear with a certain offset distance between the axes of the small wheel and the large wheel. Spiral bevel gear can be regarded as a special case of hypoid gear (for the zero offset of hypoid gear, similarly, straight bevel gear can also be regarded as an unbiased hypoid gear with zero longitudinal curvature, and helical cylindrical gear can also be regarded as a hypoid gear with zero longitudinal curvature and zero axis intersection angle. In the current new type of bevel worm transmission, it can be regarded as a special case of hypoid gear transmission.
Therefore, many gear drives can be regarded as some special cases of hypoid gears. As shown in the figure, (a) is an ordinary cylindrical worm, (c) is a spiral bevel gear, and the area (b) between (c) – (a) is a hypoid gear. In this range, the hypoid gear has a lot of room for expansion. When the number of small gear teeth decreases, the offset distance increases, and even evolves into a conical worm. Therefore, hypoid gears have a wide range of application in transmission structure.