| 摘要 |
PURPOSE:To decrease sounds in case of working and enable the control of operating speed by a method wherein a drive coil and a speed sensor are mounted, currents supplied to the drive coil are controlled by the detecting output of the speed sensor and speed-servo is applied. CONSTITUTION:A discoid yoke 2 is disposed at an approximate central section of a cylindrical yoke 1 toward the inside, center yokes 3, 4 are mounted at a central section of the yoke 2 and ringed magnets 5, 6 are installed at both sides of the yoke 2. Bobbins 9, 10 are each fitted to the center yokes 3, 4 in slide-possible shapes. A drive coil 11 and a speed detecting coil 12 are each wound on the bobbins 9, 10, and the bibbins 9, 10 are connected by several connecting rods 14 penetrating a through hole 13 of the yoke 2. When the drive coil 11 is conducted, the coil 11 is moved in the axis direction, the speed detecting coil 12 is also moved together with the coil 11, and current, proportional to the speed flow through the coil 12, thus allowing speed-servo by the output. |
