| 摘要 |
PURPOSE:To position an acting point at a neutral point constantly so as to prevent reduction of a resonance number by adjusting balance force relative to change of weight of a spindle head corresponding to the output of an error counter by means of a switching element which is energized only when the head is stopped. CONSTITUTION:If a position command value is zero when a spindle head 1 is stopped, a reversing torque acts on a ball spring 7 because of suspension by a load W, and the spindle head 1 descends until it balances with the output torque of a drive motor 8, where a position deflection quantity DELTAZ is produced, detected by a linear scale 25, and fed back to an error counter 26, so an error output signal is amplified to act on the drive motor 8 as a voltage. The deflection quantity DELTAZ is transmitted to a hold circuit 30 to be an input control voltage to an electropneumatic pressure converter 31, and an air pressure in proportion to the input acts on a diaphragm 24a to adjust pressure from a compressor 22 and act on a piston 18 to produce a balance force F. Therefore the spindle head 1 moves upward, and the deflection quantity DELTAZ is reduced, and when it becomes zero, a switching element 28 gets off. |
