Angle measuring instrument

The utility model relates to an angle measuring instrument which is characterized in that the angle measuring instrument comprises a base seat made of a granite material, a through hole is arranged in the base seat, a direct drive motor is arranged inside the through hole, a stator of the direct drive motor is fixedly connected with a shaft sleeve, the shaft sleeve is fixedly connected on the base seat, a rotor of the direct drive motor is connected with a stepped shaft through an end plate and a bolt, a dense ball bearing is arranged between the stepped shaft and the shaft sleeve, an end cap is arranged at the bottom of the dense ball bearing, a circle of protruded shaft shoulders is arranged in the middle of the stepped shaft, the shaft shoulders are supported at the top of the shaft sleeve through a pressure bearing, a flange is fixedly connected at the top of the shaft sleeve, the top of the flange is fixed at an outer ring of a circular grating angle encoder, an inner ring of the circular grating angle encoder is fixedly supported at the top of the shaft shoulder, a retaining ring is connected between the top of the inner ring of the circular grating angle encode and the stepped shaft in a sealing way, and the top of the stepped shaft is fixedly connected with a support platform; the rotor of the direct drive motor is connected with a control system, and the inner ring of the circular grating angle encode is connected with a data processing system of a computer. The angle measuring instrument can be widely used in the angle measuring of the angle encoder, the optical prism, the self-alignment light pipe, the theodolite, and the like.