ねじ締結におけるトライボロジー

抄録

It is well known that variations in the frictional coefficients between thread surfaces and bearing surfaces cause tightening error on the torque control method. Recent years, the special lubricants for bolt tightening have been developed to reduce the variations of the frictional coefficients. However, lubricants alone cannot reduce the variation in the frictional coefficients. In this article, I introduce the improvement of the tightening accuracy in the bolt tightening that we have been researching on. The squareness error of bearing surface on the bolts must be reduce less than 0.2° in order to improve the tightening accuracy. Then polyisobutylene is effective for reduction of variation in friction coefficients between thread surfaces and bearing surfaces.