There are two main types of grinding equipment for rolling NSK bearing rings: centering fixture and centerless fixture.
Centering fixture and its characteristics: In the work, if the working center is fixed relative to the clamping element of the fixture, then this fixture is called centering fixture.
The centering fixture is mounted on the spindle of the machine tool, and the center of the spindle is not the center of the fixture. In the grinding of NSK bearing rings, the centering jig generally has several kinds of sleeve jig, mandrel and diaphragm jig. The ferrule fixture is now obsolete.
Compared with centerless fixtures, diaphragm clamps have the following disadvantages:
1, the fixture and the workpiece shaft are fixed together, and the radial and axial circle runout of the workpiece shaft is equal to the transmission processing error.
2, the workpiece is easy to produce clamping deformation, so that the grinding surface appears polygonal
3, the scope of adaptation is narrow.
4, loading, unloading is not convenient, not easy to achieve automation.
Centerless fixture and its characteristics: a series of shortcomings of centering fixture led to the birth of centerless fixture. The most fundamental difference between centerless fixture and centerless fixture is that the workpiece rotation axis changes with the actual size and geometric shape of the positioning surface, mainly because there is no rigid link between the workpiece and the workpiece shaft. The significant advantages of centerless fixture are: high repetitive positioning; The radial runout of the main shaft does not affect the machining accuracy, and the radial runout of the main shaft is not equal to the transmission error to the machining. No clamping deformation, easy adjustment; Easy loading and unloading, easy to automate.