| 摘要 |
PURPOSE:To keep pump performance constant by detecting the position of an armature, comparing the detected value with a standard signal consisting of the upper limit value and the lower limit value, and keeping the moving stroke of the armature constant. CONSTITUTION:The position of an armature 6 detected by a position detecting circuit 7 is input into an operation processing part 5. In the operation processing part 5, a position detection signal is compared with a standard signal consisting of the upper limit value and the lower limit value. The control signal of a switching circuit 8 is out. put in order that the non-pulse time width of pulse current i is lengthened when a position detection signal exceeds the upper limit value, and the non-pulse time width of pulse current i is shorted when a position detection signal is shorter then the lower limit value. Accordingly, the moving stroke of the armature 6 is kept constant and also the stroke of a piston connected to the armature 6 is held constant, and so pump performance can be kept constant. |
