US 12,276,630 B2
Oil film state detection method, state detection device, and program
Shunsuke Iwase, Kanagawa (JP); and Taisuke Maruyama, Kanagawa (JP)
Assigned to NSK LTD., Tokyo (JP)
Appl. No. 18/246,990
Filed by NSK LTD., Tokyo (JP)
PCT Filed Sep. 24, 2021, PCT No. PCT/JP2021/035206
§ 371(c)(1), (2) Date Mar. 28, 2023,
PCT Pub. No. WO2022/071164, PCT Pub. Date Apr. 7, 2022.
Claims priority of application No. 2020-163963 (JP), filed on Sep. 29, 2020; and application No. 2021-137564 (JP), filed on Aug. 25, 2021.
Prior Publication US 2023/0408435 A1, Dec. 21, 2023
Int. Cl. G01N 27/22 (2006.01); F16C 33/66 (2006.01)
CPC G01N 27/221 (2013.01) [F16C 33/6688 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A state detection method for detecting an oil film state according to a lubricant in a device configured to lubricate a plurality of parts with the lubricant, the method comprising:
a measurement step of measuring impedance and a phase angle of an electric circuit by applying an AC voltage to the electric circuit configured with the plurality of parts while changing a frequency; and
a derivation step of deriving an oil film thickness according to the lubricant and a parameter indicating an electrical characteristic according to the oil film thickness, based on a relative dielectric constant at a high frequency limit of the lubricant defined based on a composition of the lubricant, and the impedance and the phase angle measured in the measurement step,
wherein the relative dielectric constant at the high frequency limit of the lubricant is a relative dielectric constant at the high frequency limit of the lubricant in a bulk state.