Other

Tooru Imai

Akira Imai

Yutaka Imai

Atsushi Imai

A bolt-axial-force measuring method and instrument capable of easily and precisely measuring an axial force of a bolt are provided. The bolt is screw-joined and coupled to a piston of a bolt tensioner, and a hydraulic pressure is supplied to its pressure chamber so that the bolt is elongated by applying a tensile force equal to or more than a necessary bolt-fastening force. A nut separating from a fastened member due to the elongation of the bolt is seated again on the fastened member, and the hydraulic pressure in the pressure chamber is discharged to release the tensile force of the bolt. A pressure change of the pressure chamber from which the hydraulic pressure is discharged is detected by a pressure sensor, a point where a change rate of the pressure change detected by a measuring apparatus is suddenly reduced is detected as an inflection point, and a pressure value of the pressure chamber at the inflection point is multiplied by a pressure receiving area of the pressure chamber, whereby the axial force of the bolt is calculated.

Method of measuring axial force of bolt and instrument for measuring axial force of bolt

A rotor 16 rotatably installed on a casing 10 is in contact with a container hole 11 of the casing 10, and the rotor 16 is equipped with a rotating shaft 17 which rotates around a rotation center O.sub.2 at a position deviated from a reference axis O.sub.0 of a container chamber by a distance E. An eccentric bearing 25 is rotatably attached to the casing 10, and has a rotation center O.sub.1 at a position deviated from both the rotation center O.sub.2 and the reference axis O.sub.0 by a predetermined distance. The eccentric bearing 25 rotates in accordance with rotation of the rotating shaft 17, and the rotor 16 is thereby brought into contact with the sliding contact portion 11a with a predetermined stress. As a result, it is possible to set large tolerances of processing precision of components of a driving device having a rotating member and a casing containing the rotating member.

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Saitama, Japan

Tooru Imai