Planar secondary envelope toroidal worm gear case

The utility model discloses a planar secondary envelope toroidal worm gear case which comprises a worm gear case body, wherein a case cover is arranged at the upper end of the worm gear case body. The worm gear case body is internally provided with two cone roller bearings; a planar secondary envelope toroidal worm is arranged between the two cone roller bearing; the middle of the planar secondary envelope toroidal worm is engaged with a worm gear; and an output shaft is connected with the middle of the worm gear in a penetrating manner. A motor is arranged on the right side of the planar secondary envelope toroidal worm and is in drive connection with the planar secondary envelope toroidal worm via a motor transmission shaft, and an oil seal is arranged on the outer side of the left end of the motor transmission shaft. Mounting holes are formed at the bottom of the worm gear case body. The case employs multi-tooth engagement and double-line contact, is wide in working flank, low in flank pressure, good in lubrication condition, low in machine temperature, large in equivalent curve radius, high in transmission efficiency, high in carrying capacity, high in precision, light in transmission and long in service life, and a tooth flank is easy to grind and can reach high hardness.