Gear assembly, timepiece, and gear assembly manufacturing method

Patent metadata

Field	Value
Publication number	US-2025103005-A1
Application number	US-202418892025-A
Country	US
Kind code	A1
Filing date	Sep 20, 2024
Priority date	Sep 25, 2023
Publication date	Mar 27, 2025
Grant date	—

Abstract

Disclosed is a gear assembly, including: a shaft; a spur gear that is made of a material having a crystal lattice plane and through which the shaft is inserted; and a fixing member that fixes the spur gear to the shaft.

First claim

What is claimed is:

1 . A gear assembly, comprising:
a shaft; a spur gear that is made of a material having a crystal lattice plane and through which the shaft is inserted; and a fixing member that fixes the spur gear to the shaft.

2 . The gear assembly according to claim 1 , wherein
the spur gear includes a gearwheel through which the shaft is inserted and/or a pinion through which the shaft is inserted, and the fixing member fixes the gearwheel and/or the pinion to the shaft.

3 . The gear assembly according to claim 2 , wherein
the gearwheel includes a mark for aligning a circumferential direction with the pinion, and the mark is formed at a position where:
the mark is covered by a tooth of the pinion when the pinion is assembled in a proper circumferential direction; and
the mark is exposed through between teeth of the pinion when the pinion is not assembled in the proper circumferential direction.

4 . The gear assembly according to claim 3 , wherein the gearwheel has a hole for detecting a position of a hand.

5 . The gear assembly according to claim 4 , wherein the hole for detecting the position of the hand also serves as the mark.

6 . The gear assembly according to claim 1 , wherein the spur gear is made of silicon.

7 . The gear assembly according to claim 6 , wherein
the spur gear is a gearwheel through which the shaft is inserted, the shaft includes an insertion portion and a flange that is larger in diameter than the insertion portion, and the shaft has an escape groove in a corner portion provided between the insertion portion and a surface of the flange that contacts the gearwheel.

8 . The gear assembly according to claim 1 , further comprising a spacer that is made of a material having a crystal lattice plane and through which the shaft is inserted, wherein
the fixing member fixes the spacer to the shaft.

9 . The gear assembly according to claim 8 , wherein the spacer is made of silicon.

10 . The gear assembly according to claim 9 , wherein
the shaft includes an insertion portion and a flange that is larger in diameter than the insertion portion, and the shaft has an escape groove in a corner portion provided between the insertion portion and a surface of the flange that contacts the spacer.

11 . The gear assembly according to claim 1 , wherein
the spur gear is a gearwheel through which the shaft is inserted, the shaft is integrally formed with a pinion that is smaller in diameter than the gearwheel, and the shaft has an escape groove in a corner portion provided between the shaft and a surface of the pinion that contacts the gearwheel.

12 . A timepiece, comprising:
a wheel train mechanism that includes the gear assembly according to claim 1 ; and a case that houses the wheel train mechanism.

13 . A timepiece, comprising:
a wheel train mechanism that includes the gear assembly according to claim 2 ; and a case that houses the wheel train mechanism.

14 . A timepiece, comprising:
a wheel train mechanism that includes the gear assembly according to claim 6 ; and a case that houses the wheel train mechanism.

15 . A timepiece, comprising:
a wheel train mechanism that includes the gear assembly according to claim 8 ; and a case that houses the wheel train mechanism.

16 . A timepiece, comprising:
a wheel train mechanism that includes the gear assembly according to claim 11 ; and a case that houses the wheel train mechanism.

17 . A method for manufacturing a gear assembly that includes:
a gearwheel of a wheel train mechanism of a timepiece; and a pinion that is smaller in diameter than the gearwheel, the method comprising:
assembling the gear assembly by inserting a shaft through the gearwheel and the pinion that are manufactured by photolithography from a single silicon wafer.

18 . The method for manufacturing the gear assembly according to claim 17 , wherein in the assembling, the gearwheel and the pinion are manufactured by photolithography from the single silicon wafer in which the gearwheel and the pinion with larger diameters are disposed closer to a centerline of the silicon wafer.

19 . The method for manufacturing the gear assembly according to claim 17 , wherein
the gear assembly further includes a spacer that adjusts a position of the gearwheel and a position of the pinion, and in the assembling, the shaft is inserted through the gearwheel, the pinion, and the spacer that are manufactured by photolithography from the single silicon wafer.

20 . The method for manufacturing the gear assembly according to claim 17 , wherein in the assembling, the shaft is inserted through the gearwheel and the pinion such that
a mark formed on the gearwheel for aligning a circumferential direction with the pinion is covered by a tooth of the pinion, wherein
the mark is formed at a position where:
the mark is covered by the tooth of the pinion when the pinion is assembled in a proper circumferential direction; and
the mark is exposed through between teeth of the pinion when the pinion is not assembled in the proper circumferential direction.

Assignees

• Casio Computer Co Ltd

Inventors

• Saito Yuta
• Iida Masataka

Classifications

• G04B13/022

  with parts made of hard material, e.g. silicon, diamond, sapphire, quartz and the like · CPC title

• B81B2203/056

  Rotation in a plane parallel to the substrate · CPC title

• B81B2203/0353

  Holes · CPC title

• B81B2201/035

  Microgears · CPC title

• B81C3/004

  Active alignment, i.e. moving the elements in response to the detected position of the elements using internal or external actuators · CPC title