托辊的作用是支撑输送带和物料重量。托辊运转必须灵活可靠。减少输送带同托辊的摩擦力，对占输送机总成本25%以上的输送带的寿命起着关键作用。虽然托辊在带式输送机中是一个较小部件，结构并不复杂，但制造出高质量的托辊并非易事。 The role of idlers is to support the weight of conveyor belts and materials. The operation of the roller must be flexible and reliable. Reducing the friction force between the conveyor belt and the idler will play a key role in the life span of the conveyor belt which occupies the total cost of the conveyor more than 25%. Although the roller is a small component in the belt conveyor, the structure is not complicated, but it is not easy to create a high quality idler. 判断托辊好坏的标准有以下几条：托辊径向跳动量；托辊灵活度；轴向窜动量。 There are following criteria for judging whether the idler is good or bad: the radial runout of the idler, the dexterity of the idler, and the axial momentum.