Inner ring positioning flatness testing machine

An inner ring positioning flatness testing machine belongs to the field of mechanical testing devices and comprises an operating platform, a positioning mechanism used for positioning an inner ring ofa wheel rim and a limiting guide mechanism used for limiting and guiding the wheel rim are arranged on the operating platform. The detection mechanism is used for detecting the flatness of the rim; and the sliding rails are respectively connected with the positioning mechanism, the limiting guide mechanism and the detection mechanism in a sliding manner. Wherein the positioning mechanism comprises a driving wheel and two driven wheels, the driving wheel and the two driven wheels can respectively slide along with the driving wheel mounting seat and the driven wheel mounting seat along the extension direction of the slide rail at the corresponding position and are used for abutting against the inner ring wall of the wheel rim to position the wheel rim, and the driving wheel is driven by a motor to rotate and is use