| 摘要 |
PURPOSE:To sufficiently satisfy torque, high-speed following ability, and position accuracy which are required for driving a seam-forming device of a sewing machine by making the excitation-phase switching period of a pulse motor variable. CONSTITUTION:The number of steps of a pulse motor which is required for the movement of the pulse motor driving a seam-forming device system 4 is output from a seam-information memory device 2. A control circuit 7 determines the method of switching the driving cycle so as to drive the pulse motor in an optimal manner depending on the numbe of moving steps and asigns the pulse number to individual circuits 5a-5d. The circuits 5a-5b output the specified pulse number at every oscillating period, which is specified for each circuit, sequentially from the circuit a, and stops the oscillation. A driver 3 that receives the pulse train has a logic constitution which generates an exciting signal for the pulse motor, and shifts the exciting phase one by one. The signal from a needle-position sensor 6 accesses the seam-information memory device 2. |
