| 摘要 |
PURPOSE:To improve control responsiveness by starting a stepping motor for a motor control part between self-starting ranges, and installing a control means for adjusting it speed within a through range, in a device which controls an EGR valve with the stepping motor. CONSTITUTION:When a pulse-form current flows in a coil 3, a rotor 7 rotates as far as a specified angle at each pulse, and a push rod 6 screwed in the rotor moves in the axial direction. A PM type stepping motor M is used as an actuator for an EGR valve. As the driving system, bipolar drive making a current flow into the whole coil is adopted. Then, each pattern of starting, adjustable speed, reverse rotation and stoppage in this stepping motor M is stored in a motor control part (microcomputer) in advance, and at time of driving the stepping motor M, a driving pulse number per unit time is increased or decreased along these patterns, then the stepping motor M is started within a self-starting range, thus its speed is made so as to be adjustable within a through range. |
