| 摘要 |
PROBLEM TO BE SOLVED: To clamp a die to a punch with a high torque by using a small-sized control motor having a low rated torque by clamping the die to the punch in a state where the motor is set at a torque higher than the rated torque and lowering the torque of the motor from the rated value after the die is maintained in the clamped state by means of a brake. SOLUTION: A die 7 is clamped to a punch 6 by pressing the die 7 against the punch 6 so as to hold a lead frame between the die 7 and punch 6 by moving the die 7 in the direction shown by the arrow by utilizing the thrust of a servo motor 3. The die 7 is clamped to the punch 6 when the torque of the motor 3 instantaneously becomes the maximum. Immediately after the clamping, the clamping force applied to the die 7 is maintained by holding a vertical screw 8b with a brake body 10 and, while the clamping force is maintained, the torque of the motor 3 is lowered from the rated torque. Therefore, a strong clamping force can be applied to the die 7 for a long time by using a small-sized servo motor which is less in parts cost and the power consumption when the servo motor is used can be suppressed. |
