Yazaki Corporation

Hidemasa Umehara

Yoshihisa Yamada

Kazuya Tsubaki

Masaki Oishi

Yoshiyuki Muramatsu

A drive device includes stepper motors, each having an excitation coil and a rotor rotating based on variation in the excitation state of the excitation coil; driven members, each moving in accordance with the rotation of the rotor of the corresponding stepper motor; stoppers, each stopping the driven member mechanically at a zero position; and a controller, controlling the respective stepper motors so as to selectively performs either a normal operation in which the stepper motor is driven so as to rotate, or a zero-position detection operation in which the stepper motor is driven so that the driven member is moved to the stopper. The controller starts to perform the zero-position detection operation simultaneously in all of the stepper motors and changes the stepper motor which has terminated the zero-position detection operation to the normal operation without waiting for the termination of the zero-position detection operation in other stepper motors.

Drive device for stepper motor and indicating apparatus using the same

When excited states of excitation coils are controlled at a both excitation step of magnetizing both of two excitation coils, an initializing driving means inputs excitation pulses in which a duty ratio thereof at an interval of time controlled by the both excitation step is less than 1 to the excitation coils. Contact detecting means detects contact based on voltages generated at the excitation coils when the excitation pulses are not inputted.

Initializing drive apparatus

A drive unit for calibrating an indicator/meter of a vehicle is provided in which a pointer in an indicator for a vehicle can point immediately after an ignition switch is turned ON, and the frequency of seeing motion of the pointer in an initializing operation by a car driver is reduced. A sensing mechanism ( - ) is provided to sense an open/close operation of a door. Correspondingly to the sensing of the sensing mechanism ( - ), a drive-start mechanism ( - ) starts rotation of a stepping motor using a drive mechanism ( - ) for initialization. The drive mechanism ( - ) during initialization rotates the stepping motor to move a driven member toward a stopper.

Drive unit for initialization

A cross coil type indicating instrument including a coil bobbin having first and second chambers separately formed inside, a rotary shaft to which a magnet rotor and a rotary gear are secured in the first chamber, and an eccentric shaft to which a transmission gear is secured in the second chamber so as to engage with the rotary gear. A pointer is secured to an end portion of the eccentric shaft. Further, the coil bobbin has a coil winding portion with a flat surface outside where the first chamber is formed, and two coils are wound on the coil winding portion in such a manner that they are perpendicular to each other. Hence, the coils are guided linearly when wound on the coil winding portion.

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Shizuoka, Japan

Hidemasa Umehara