ベルト式無段変速機用特殊Vベルトについて (III)

This paper deals with no-load-fatigue test for belts conducted using several kinds of special V-belts for variable speed mechanisms. After the experiment, we decided what type of belt was the strongest, and improved the belt to make it stronger.<BR>After having designed a new belt, we performed the fatigue test on it by changing the tension in it, and found the limit of safety tensions of the new belt. Fig. 1 and 2 show the testing apparatus employed.<BR>In Fig. 1, (1) belt tested<BR>(2) sheaves<BR>(3) lock nuts<BR>(4) plate on which sheaves are set, sliding through guides (5)<BR>(5) guides of plate (4)<BR>(6) pulleys for hanging the weight<BR>(7) ropes<BR>(8) rope fastening<BR>(9) weight<BR>(10) motor (7, 2000r.p.m.)<BR>(11) transmission belts.<BR>We used four kinds of belts for the fatigue test. Fig. 3 shows the dimension of the belt tested. Fig. 4-7 show the section of these belts. We indicate the endurance of belt by the number of bending.<BR>If I put n, number of bending, <BR>D, diameter of belt, <BR>N, rpm, <BR>L, belt length, <BR>t, time of endurance, <BR>then<BR>Observing the fatigue test, we found that the initial crack took place in the core of V belt, and that, after a while, at both sides of V belt, it started to break. Gradually the cracks became larger, and at last, the side cracks and the core crack jointed together and then the belt broke.<BR>While observing of the fatigue test, I designed new belts, which are shown in Fig. 9, 10. We call these belts device A, and device B. We made a running test, and measured the coefficient of friction and the amount of abrasion of belt, using these belts.