Design of inspection fixture body
The main structure of the special inspection tool is the inspection tool body, which is mainly composed of the inspection tool body, measuring seat, fixed probe, movable probe, mandrel positioning block, guide seat and locking screw.
The measuring base is fixed on the measuring body of the inspection tool by the inner hexagon screw, the mandrel positioning block is connected with the movable measuring head by the inner hexagon screw, and the fixed measuring head, the positioning support and the guide block are welded and fixed on the measuring body of the inspection tool.
The diameter of the right end of the movable probe is φ 20f6 journal and guide body φ The inner hole of 20h7 is matched to ensure that the movable probe can move left and right.
The circular groove on the mandrel positioning block on the fixture body has the following features in design:
(1) The four supporting locating bottom planes on the measuring body of the inspection tool constitute plane B, and the central axis of the circular groove of the mandrel locating block must pass through this plane.
(2) Guarantee and management of working face with fixed probe and movable probe φ The 139.5mm cylinder contacts at the same time, and the center of the cylinder is perpendicular to plane B. The center distance between the cylinder and the circular groove of the mandrel positioning block is 60 ± 0.01mm.
The above features ensure that after the workpiece is positioned, the center of the arc groove of the mandrel positioning block of the fixture body coincides with the center of the inner arc radius r70 to be detected, which conforms to the principle of reference coincidence and ensures the accurate positioning of the workpiece.
The following points should be paid attention to in the design of the inspection tool body:
The working plane of the pedestal must be not only perpendicular to datum plane a, but also perpendicular to plane B;
In order to ensure enough wear resistance of the working surface of the fixed probe and the movable probe, the surface must be quenched with high frequency;
In order to install the inspection tool into the outer circle of the convex cone of the workpiece and locate it smoothly, the design should ensure that when the workpiece is clamped, there must be a 2mm distance between the movable probe in the horizontal direction and the left end surface of the guide seat on the measuring body.