Theoretical and Experimental Investigation of a New Plane Toothed Wheel and Its Enveloping Hourglass Worm

Abstract

This paper relates to the properties of the surface of contact or the line of contact on a new plane toothed wheel which is inclined properly to the axis of the wheel and on its enveloping hourglass worm by using the theory of envelope, numerical computations, manufacturing process of this hourglass worm gears, and their experimental results. From this investigation, it can be ascertained that the surface of contact is nearly tangential to the circumference of the worm surface. The line of contact is almost upright to the direction of sliding surface. When the inclination angle of the plane tooth of the wheel axis is 22 deg, the tooth bearing on a wheel tooth is in its center portion, and good condition. We carried out various tests with a speed-reducing gear solely manufactured by several trials, using such materials as ABB2 (special aluminum bronze) for a worm and S45C (high-frequency-quenched) for a wheel. Results were obtained from the tests. They are as follows: because of no wearing in a wheel, little irregularity is caused on a worm tooth form; wearing in a worm is very little because the interlocking is made with the entire surface; power consumption may be reduced by more than 10 percent as compared with a conventional unit. Furthermore, we are confident that a power transmission capacity may be more than doubled also by this new product.