Hairspring material for mechanical timepiece and hairspring using the same

Patent metadata

Field	Value
Publication number	US-9395692-B2
Application number	US-201314421233-A
Country	US
Kind code	B2
Filing date	Aug 29, 2013
Priority date	Aug 31, 2012
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

A hairspring material for a mechanical timepiece includes an alloy which contains 37.5 to 39.5% by mass of Ni, 9.2 to 9.9% by mass of Cr, 0.35 to 0.55% by mass of Ti, and 0.6 to 0.9% by mass of Be, based on the total amount of the alloy, and contains in the remainder Fe and unavoidable impurities, the alloy being an alloy containing, as the unavoidable impurities, C (carbon), Mn in an amount of more than 0% by mass but not more than 0.5% by mass and Al in an amount of more than 0% by mass but less than 0.03% by mass, the amount of the C (carbon) being limited to not more than 0.03% by mass. The hairspring material can provide a smaller variation in Young's modulus than that of conventional hairspring materials.

First claim

The invention claimed is:

1. A hairspring material for a mechanical timepiece, comprising an alloy which contains 37.5 to 39.5% by mass of Ni, 9.2 to 9.9% by mass of Cr, 0.35 to 0.55% by mass of Ti and 0.6 to 0.9% by mass of Be, based on the total amount of the alloy, and contains a remainder comprising Fe and unavoidable impurities, said alloy being an alloy containing, as the unavoidable impurities, C (carbon), Mn in an amount of more than 0% by mass but not more than 0.5% by mass and Al in an amount of more than 0% by mass but less than 0.03% by mass, the amount of said C (carbon) being limited to not more than 0.03% by mass, wherein Ti and C are contained as TiC and the size of the TiC is not more than 5 μm.

2. The hairspring material for a mechanical timepiece as claimed in claim 1 , which comprises an alloy wherein the amount of C (carbon) of the unavoidable impurities is limited to not more than 0.01% by mass.

3. The hairspring material for a mechanical timepiece as claimed in claim 2 , wherein Ti and C are contained as TiC and the size of the TiC is not more than 3 μm.

4. A hairspring obtained from the hairspring material for a mechanical timepiece as claimed in claim 3 .

5. A mechanical timepiece comprising the hairspring as claimed in claim 4 .

6. A hairspring obtained from the hairspring material for a mechanical timepiece as claimed in claim 2 .

7. A mechanical timepiece comprising the hairspring as claimed in claim 6 .

8. A hairspring obtained from the hairspring material for a mechanical timepiece as claimed in claim 1 .

9. A mechanical timepiece comprising the hairspring as claimed in claim 8 .

Assignees

• Citizen Holdings Co Ltd
• Citizen Watch Co Ltd
• Hitachi Metals Ltd
• Neomax Materials Co Ltd
• Hitachi Metals Neomaterial Ltd

Inventors

• Hirai Yoshirou
• Matsumoto Shinichi
• Tsuchiya Kenji
• Yamamoto Shinji

Classifications

• C21D9/02 Primary

  for springs · CPC title

• C22C38/00

  Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00) · CPC title

• F16F1/10

  Spiral springs with turns lying substantially in plane surfaces {(F16F1/326 takes precedence)} · CPC title

• G04B17/06 Primary

  Oscillators with hairsprings, e.g. balance {(electrically driven balances G04C3/04; contacts actuated by a balance G04C13/065)} · CPC title

• C22C38/02

  containing silicon · CPC title