Timepiece and motor control method

Patent metadata

Field	Value
Publication number	US-11016446-B2
Application number	US-202016752897-A
Country	US
Kind code	B2
Filing date	Jan 27, 2020
Priority date	Feb 6, 2019
Publication date	May 25, 2021
Grant date	May 25, 2021

Abstract

A timepiece includes a stepping motor having a rotor and a coil, and a drive circuit that applies a first drive pulse having a stable stationary position at a rotor rotation angle of 90 degrees or less from a reference position and a second drive pulse having the stable stationary position at a rotor rotation angle of 90 degrees or more from the reference position, as a pulse for driving the rotor, to the coil. When a period during which the pulse is not applied to the coil is assumed as a waiting period, the drive circuit generates the waiting period after a first application of the second drive pulse after an application of the pulse to the coil is started and rotates the rotor by one or more turns without passing through the waiting period at at least one predetermined timing after the waiting period.

First claim

What is claimed is:

1. A timepiece comprising:
a stepping motor in which a rotor magnetized in two poles is rotationally driven in a stator connected to a driving coil;
a drive circuit that applies a first drive pulse having a stable stationary position at a rotor rotation angle of 90 degrees or less from a reference position and a second drive pulse having the stable stationary position at a rotor rotation angle of 90 degrees or more from the reference position, as a drive pulse that is a pulse for driving the rotor, to the driving coil; and
a control circuit that controls application of the drive pulse by the drive circuit, wherein
when a period during which the drive pulse is not applied to the driving coil is assumed as a waiting period, the drive circuit generates the waiting period after a first application of the second drive pulse after an application of the drive pulse to the driving coil is started, and rotates the rotor by one or more turns without passing through the waiting period at at least one predetermined timing that is determined in advance after the waiting period.

2. The timepiece according to claim 1 , wherein
when a process in which the drive circuit continuously applies the second drive pulse to the driving coil after the drive circuit applies the first drive pulse to the driving coil is assumed as one unit process, the drive circuit applies the drive pulse to the driving coil so as to generate the waiting period every N (N is an integer of 2 or more) unit processes.

3. The timepiece according to claim 1 , wherein
the drive circuit applies the drive pulse to the driving coil so as to rotate the rotor by one or more turns without passing through the waiting period at at least one application timing and applies the drive pulse to the driving coil so that the waiting period is randomly generated in a period other than the application timing.

4. The timepiece according to claim 1 , wherein
the waiting period is 0.5 ms or more and 2 ms or less.

5. A motor control method performed by a motor drive device, which includes a stepping motor in which a rotor magnetized in two poles is rotationally driven in a stator connected to a driving coil, a drive circuit that applies a first drive pulse having a stable stationary position at a rotor rotation angle of 90 degrees or less from a reference position and a second drive pulse having the stable stationary position at a rotor rotation angle of 90 degrees or more from the reference position, as a drive pulse that is a pulse for driving the rotor, to the driving coil, and a control circuit that controls application of the drive pulse by the drive circuit, the motor control method comprising:
a control step of, when a period during which the drive pulse is not applied to the driving coil is assumed as a waiting period, controlling the drive circuit to generate the waiting period after a first application of the second drive pulse after an application of the drive pulse to the driving coil is started and rotate the rotor by one or more turns without passing through the waiting period at at least one predetermined timing that is determined in advance after the waiting period.

Assignees

• Seiko Instr Inc

Inventors

• Sakai Satoshi
• Nobe Tetsuya

Classifications

• H02P8/02

  specially adapted for single-phase or bi-pole stepper motors, e.g. watch-motors, clock-motors · CPC title

• H02P8/06

  in selected direction of rotation · CPC title

• H02P8/18

  Shaping of pulses, e.g. to reduce torque ripple {(Reducing overshoot H02P8/32 takes precedence)} · CPC title

• G04C3/14 Primary

  incorporating a stepping motor (G04C3/02 - G04C3/12 take precedence {; generating commutating pulses in primary clocks G04C13/0463}) · CPC title