| 摘要 |
PROBLEM TO BE SOLVED: To make a device compact and improve its efficiency. SOLUTION: A magnet is secured to outer yokes 11b and 11b and a bobbin is inserted into the outside of a center yoke 11c. Then the bobbin is wound by a coil 14, and when the coil 14 is energized, a thrust works on the bobbin and a bonding head turns on a bearing 15d. In this case, the upper and lower ends of the yokes 11b and 11b and yoke 11c are connected with a bottom yoke 11a and a ceiling yoke 11d and a magnetic circuit is blocked. Therefore, it becomes unnecessary to regulate the wall thickness of the yoke 11 and to correct the magnetic balance, so that the device can be made compact and its efficiency be improved. |
