TIMEPIECE MOVEMENT AND TIMEPIECE

• US 20200133205A1
• Filed: 10/09/2019
• Published: 04/30/2020
• Est. Priority Date: 10/24/2018
• Status: Active Grant

• Current Assignee: Seiko Instruments Incorporated (Seiko Group)
• Original Assignee: Seiko Instruments Incorporated (Seiko Group)
• Inventors: FUJIWARA, TOSHIYUKI, OGASAWARA, Kenji
• Granted Patent: US 11,334,031 B2
• Time in Patent Office: Days
• CPC Class Codes: G04C 13/11 with rotating armature
• CPC Class Codes: G04C 3/008 Mounting, assembling of components
• CPC Class Codes: G04C 3/143 Means to reduce power consumption by reducing pulse width or amplitude and related problems, e.g. detection of unwanted or missing step
• CPC Class Codes: G04C 3/146 incorporating two or more stepping motors or rotors

Abstract

A timepiece movement capable of suppressing generation of malfunction of a hand is provided. The movement includes an indicator hand wheel which is provided so as to be rotatable and to which an indicator hand is mounted; an indicator hand stepping motor rotating and driving the indicator hand wheel in both directions; an hour wheel provided so as to be rotatable around a first rotation axis different from a rotation axis of the indicator hand wheel and having a first shaft portion which extends along the first rotation axis and on the outer peripheral surface of which there is provided a contact portion that the indicator hand can abut, with the distance of the contact portion from the first rotation axis varying in accordance with a position in the peripheral direction around the first rotation axis; and an hour hand stepping motor rotating and driving the hour wheel and provided separately from the indicator hand stepping motor.

Claims

1. A timepiece movement comprising:

a first wheel which is provided so as to be rotatable and to which a hand is mounted;

a first motor rotating and driving the first wheel in both directions;

a second wheel provided so as to be rotatable around an axis different from a rotation axis of the first wheel and having a shaft portion which extends along the axis and on an outer peripheral surface of which there is provided a contact portion the hand can abut, with the distance of the contact portion from the axis varying in accordance with a position in a peripheral direction around the axis; and

a second motor rotating and driving the second wheel and provided separately from the first motor.

2. The timepiece movement according to claim 1, wherein the contact portion has a face-cut portion.

3. The timepiece movement according to claim 1, wherein the contact portion has a pair of face-cut portions provided parallel to each other.

4. The timepiece movement according to claim 1, wherein the contact portion is offset with respect to the axis.

5. The timepiece movement according to claim 1, wherein the first motor is equipped with a stator having one coil, and a 2-pole rotor.

6. The timepiece movement according to claim 5, wherein the stator is equipped with a stator yoke having a rotor accommodating hole in which the rotor is arranged;

the stator yoke is equipped with a pair of magnetic saturation portions generating a pair of magnetic poles different from each other around the rotor accommodating hole through excitation of the coil;

the pair of magnetic saturation portions are provided so as to be opposite each other with the rotation center of the rotor therebetween;

in the rotor accommodating hole, there are formed a pair of cutout portions exerting a retaining torque to the rotor;

the pair of cutout portions are provided so as to be opposite each other with the rotation center of the rotor therebetween;

a straight line passing through the pair of cutout portions is inclined by a predetermined angle in the normal rotation direction of the rotor with respect to a straight line passing through the pair of magnetic saturation portions; and

the contact portion is formed such that when normally rotating the rotor, when the second wheel is rotated in a state in which the hand is held in contact with the contact portion from the upstream side in the hand displacement direction, the rotor rotates to a greater degree than the predetermined angle.

7. The timepiece movement according to claim 1, further comprising a control portion controlling the first motor and the second motor,

wherein in the case where the hand comes into contact with the contact portion of the second wheel, each time a pulse rotating the second wheel is applied to the second motor a predetermined number of times, the control portion applies a pulse rotating the hand away from the second wheel to the first motor once.

8. The timepiece movement according to claim 7, wherein the predetermined number of times is one.

9. A timepiece comprising:

the timepiece movement as claimed in claim 1;

a first hand mounted to the first wheel; and

a second hand mounted to the second wheel.