托輥的作用是支撐輸送帶和物料重量。托輥運轉必須靈活可靠。減少輸送帶同托輥的摩擦力，對占輸送機總成本25%以上的輸送帶的壽命起著關鍵作用。雖然托輥在帶式輸送機中是一個較小部件，結構并不復雜，但制造出高質量的托輥并非易事。 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. 判斷托輥好壞的標準有以下幾條：托輥徑向跳動量；托輥靈活度；軸向竄動量。 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.