In order to ensure that there is no relative movement between the tool holder and the spring sleeve during the tool clamping process, that is, the tool moves synchronously with the spring sleeve in the axial direction, and at the same time ensure that the tool can maintain good axial repeat positioning accuracy after each tool change, it is necessary to ensure that the positioning end face of the tool holder and the positioning end face of the spring sleeve are always in contact during the clamping process.
To improve the working performance of the machine tool spindle and meet the requirements of automatic tool change of CNC machine tools, the designed and developed machine tool spindle shaft end spring chuck must be able to solve the following key problems well:
1. There should be sufficient contact stiffness between the contact surface of the cylindrical tool holder and the spring chuck in the clamped state. There should also be sufficient contact stiffness between the spring sleeve in the chuck and the contact surface of the tapered hole at the end of the machine tool spindle shaft in the clamped state.
2. The machine tool spindle must transmit sufficient cutting torque to the tool during processing.
3. The spring chuck adopts a spiral clamping mechanism. In addition to providing a sufficiently large radial clamping force to the tool when clamping the tool, it must also have reliable self-locking performance.
4. The tool exchange device and the spring chuck should enable the tool to have a high repeat positioning accuracy after each tool change.
5. It has the function of automatically cleaning the iron filings and dust in the tool holder and spring chuck cavity during the tool change process.
6. The spindle end of the machine tool spindle should have a simple structure and good processability to facilitate the optimized design of the spindle itself.