Explores for the source of the gears in traditional Japanese clock (Wadokei)

• DOI: 10.1299/transjsme.16-00295
• Publication Date: 2017-03-06T22:09:24Z
• Authors: Akio UEDA; Jun WATANABE; Miyako MIYAZAKI; Aizoh KUBO; Hiroaki MATSUOKA
• Keywords: Cycloid gear

The purpose of this study is to understand the nature one oldest gears used in traditional Japanese clock. Today's gear manufacturing technology Japan came mostly from Europe and America, but we do not know exactly, when how were manufactured for first time Japan. It interesting search history. also exciting tooth profile, precision accuracy gears, materials at that time. So far, there have been some studies performed mechanism clocks/watches, gears. Fortunately a chance investigate watch drive was made 1688. Tooth profile pitch error measured, transmission analysis performed. revealed extremely high without any rust more than 300 years, even though they all handmade by technician named Sukeza-emon Tsuda III. In old days, no on conjugate theory available, mysteriously, nearly form cycloid. Moreover, material investigation very interesting: texture homogeneous grain size far smaller today's comparable steel kind. Impurities it small scattered well matrix. surely sword smith. ore perhaps sand-iron refined with pine charcoal. forged hand hardly. As result quality 1688 looks better industrial steel. This research enabled us discover born developed.