Title:
SPRING WASHER, AXIAL FORCE EVALUATION METHOD AND FASTENING STATE EVALUATION METHOD
Document Type and Number:
Japanese Patent JP2018194096
Kind Code:
A
Abstract:
To provide a spring washer which can accurately evaluate an axial force and a fastening state even after the lapse of a long period of time from fastening, and an evaluation method of the axial force and the fasten state using the spring washer.SOLUTION: A spring washer W having flat-plate shaped inclined parts 6-1 to 4 having faces which form prescribed angles with respect to a center axis at equal angular intervals when viewing the angles to a center axial direction of a hole 5a is inserted between a head part of a screw or a bolt and a substance surface of a fastening object, and fastened thereto, and an amount corresponding to strain which is generated at the flat-plate shaped inclined parts 6-1 to 4 is measured. An axial force is evaluated from an average value of the amount corresponding to the strain, and a fastening state is evaluated from a difference between an amount corresponding to strain immediately after the fastening, and an amount corresponding to strain after the lapse of a long period of time. The amount corresponding to the stain can be obtained by measuring residual stress by using an X-ray diffraction measurement device. Strain gauges are pasted to the flat-plate shaped inclined parts 6-1 to 4, and a strain amount may be detected from the strain gauges.SELECTED DRAWING: Figure 1
Inventors:
UJIIE MASAHIKO
Application Number:
JP2017098779A
Publication Date:
December 06, 2018
Filing Date:
May 18, 2017
Export Citation:
Assignee:
PULSTEC IND CO LTD
International Classes:
F16B43/00; F16B31/02; G01N23/205