IP Library Granted Patent US 11,334,031
Granted Patent B2
US 11,334,031 · App. 16/597,331 · Granted May 17, 2022

Timepiece movement and timepiece

Inventors: Toshiyuki Fujiwara (Chiba, JP); Kenji Ogasawara (Chiba, JP)
Assignee: SEIKO INSTRUMENTS INC.
G04C3/146G04C3/008G04C3/143G04C13/11
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Quick Facts
Patent No.
US 11,334,031
App. No.
16/597,331
Granted
May 17, 2022
Kind
B2
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 (23)

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.

Assignments (2)
NUNC PRO TUNC ASSIGNMENT Recorded Oct 17, 2024
From: SEIKO INSTRUMENTS INC.
To: SEIKO WATCH CORPORATION
Reel/Frame 069183/0051 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 10, 2019
From: FUJIWARA, TOSHIYUKI; OGASAWARA, KENJI
To: SEIKO INSTRUMENTS INC.
Reel/Frame 050682/0059 →
Priority Claims (1)
JP JP2018-200053 · Oct 24, 2018 · national
Continuity (1)
Related Publication 20200133205A1 · Apr 30, 2020