Bando Chemical Industries, Inc.

Yoshitaka Kurose

Koji Watanabe

Kazuyoshi Tani

Both types of short aramid fibers and non-aramid synthetic fibers are extruded from a side face of each rib in a V-ribbed belt. The extruded section of the short aramid fiber is formed in curled shape. The extruded section of the synthetic fiber is formed in a sector gradually broadened toward its distal end with its non-melting condition maintained. The root portions of the extruded sections of both types of short fibers are raised from the side face of the rib. The extruded sections of the short aramid fibers are extruded in multiple directions, whereas the extruded sections of the synthetic fibers are extruded in a given direction. The extruded section of the short aramid fiber is formed longer than the extruded section of the synthetic fibers.

Power transmission belt and method for fabricating the same

Short aramid fibers extruded from a side face of each rib in a V-ribbed belt are formed in curled shape. The root portions of the extruded short aramid fibers are raised from the side face of the rib. The tip portion of each extruded short aramid fiber is bowed in a direction different from a bowing direction of its medial portion. The extruded sections of the short aramid fibers are different in bowing direction from one another to decentralize the orientation thereof.

Extruded sections of synthetic fibers extruded from a side face of each rib in a V-ribbed belt are plastically deformed in the shape of sectors gradually broadened toward their distal ends. The extruded sections of the synthetic fibers are not heated beyond their melting point during a grinding process so as to be kept unmelted. The extruded sections of the synthetic fibers are raised from the side face of the rib so that microscopic unevenness is formed over the side face of the rib. The synthetic fiber is formed of nylon with a filament diameter of 20 &mgr;m or more.

Method for fabricating power transmission belt including grinding with specified grinding wheel

In pressing a slack-side span of a V-ribbed belt, entrained about a crank pulley variable in rotational speed, auxiliary pulleys and an idler pulley, with an auto tensioner, thereby automatically balancing tension of the belt, the damping coefficient DI of the auto tensioner is set in accordance with the modulus of longitudinal elasticity of the belt. For example, when the modulus of longitudinal elasticity of the belt is at least 9800 N/100% rib and less than 29400 N/100% rib, the damping coefficient DI of the auto tensioner is set at at least 20% and less than 100%. In this manner, even if the rate at which the auto tensioner absorbs elongation of the belt is as extremely small as 0.3 to 1.0 mm/deg, a rocking motion of the auto tensioner can be avoided thereby reducing the occurrence of a slip or a frictional sound of the belt and the occurrence of abrasion and frictional sounds of friction members, such as an insert bearing and a thrust washer, of the auto tensioner.

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Hyogo, Japan

Yoshitaka Kurose