The invention discloses a
diameter-variable belt
pulley. The
diameter-variable belt
pulley comprises a guiding ring, end caps, a mandrel, a slider, a plurality of arc rings and a compression spring. A plurality of square guiding holes extending axially are circumferentially formed in the
peripheral surface of the guiding ring. Each end cap is shaped in a stepped round ring. The mandrel is shaped in a straight
barrel. The
peripheral surface of the slider is cone-shaped, the slider is provided with a plurality of inclined dovetail grooves corresponding to the square guiding hole of the guiding ring. The arc rings are spliced to form a circle. Each arc ring comprises an arc surface, an inclined dovetail tooth distributed on the inner circumferential face of the arc surface, an expanding
diameter and a shrinking diameter. One end of the compression spring supports the larger end of the slider while the other end of the same supports the inner side of one of the end caps. The diameter-variable belt
pulley has the
advantage of simple and reasonable structure. Under an action of elastic force of the spring, the slider moves along the mandrel so as to push the arc rings to expand longitudinally, and a relative large approximate circle is obtained to enable the diameter of the belt pulley to be adjustable in size, belt pulley tensing of a belt pulley
system can be achieved, and normal operation of the belt pulley
system of a
diesel engine can be guaranteed.