圧縮コイルばねの時間強度線図に関する共同研究報告

抄録

The “Research Committee on Fatigue Diagrams of Helical Coil Springs”, which ended its activities in 2015, manufactured various springs and conducted fatigue tests with the aim of investigating the validity of the JIS fatigue diagrams. As a result, it was confirmed that the JIS diagram for fatigue strength after 10⁷ cycles was considerably on the safe side. However, due to the small amount of data on the short lifespan side such as 10⁵ and 10⁶ cycles, it was not possible to reach a conclusion from a statistical analysis perspective. Therefore, this committee set test conditions and acquired fatigue data on the low-life side, which the above-mentioned committee had not been able to obtain sufficiently. In addition, statistical analysis was conducted on the test results and the results were compared with the JIS diagram on the low-life side. As a result, it was confirmed that the 50% breakage probability line for this experiment at 10⁵ and 10⁶ times corresponds to a JIS diagram with a safety factor of 1.4 to 1.8.