Rigid gear and flexible gear which are used for short-tube flexible-gear harmonic speed reducer and machining process thereof

Provided are a rigid gear and flexible gear which are used for short-tube flexible-gear harmonic speed reducer and a machining process thereof. Inner teeth of the rigid gear are gear teeth with an inclination angle alpha, the inclination direction of the inclination angle alpha is consistent with the field angle theta2 at the position of a long shaft of the flexible gear, and the inclination angle alpha is 0.1 degree to 2 degrees. Top ends of two tooth profile curve line sections of the outer tooth profile of the flexible gear are connected through a tooth top straight line section. Each tooth profile curve line section is formed by connecting upper circular radius and lower circular radius in smooth transition mode. The harmonic speed reducer comprises the rigid gear, the flexible gear and a wave generator. The ratio of the length and the inner diameter of the flexible gear is smaller than 1. The flexible gear and the rigid gear in the short-tube flexible-wheel harmonic speed reducer are both machined through a slow-feeding wire cutting off machine. The gear teeth of the flexible gear and the gear teeth of the rigid gear are meshed in the certain inclination angle. The total contact area of the meshing teeth pair is increased by 15% compared with the condition where no inclination angle exists. Overlapping ratio of the harmonic gears is improved, and harmonic transmission rigidity is improved.