Device and method for measuring axial clearance of large-size three-point angular contact ball bearing

The invention discloses a large-size three-point angular contact ball bearing axial clearance measuring device and a measuring method, and relates to the field of bearing axial clearance detection. The problem that bearing clearance measurement distortion caused by relative position deviation and angular deviation of an inner ring and an outer ring in the bearing measurement process cannot be avoided through an existing three-point angular contact ball bearing axial clearance static measurement method is solved. The middle of a hollow main shaft rotating device is rotationally connected with a main shaft bearing seat through a main shaft bearing, the lower portion of the main shaft rotating device is connected with the loading end of a main shaft loading device, the upper portion of the main shaft rotating device is sleeved with a bearing inner ring tool, and the main shaft bearing seat is sleeved with a flexible loading disc. The lower surface of the flexible loading disc is respectively connected with the l