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Idler rollers are an important component of belt conveyors. Their internal structure consists of a cylinder cover, idler roller shaft, bearings, bearing housings, seals, retaining rings, etc. They bear over 70% of the resistance during the conveying process, and are the most commonly used and frequently replaced components in belt conveyors. How to extend the service life of idler rollers is a major issue facing manufacturing units. 1. Analysis of the reasons for the short service life of idler rollers: (1) Poor sealing performance. The seal used inside the idler roller is an axial non-contact labyrinth seal. Its feature is that a very small curved gap is created between the inner and outer sealing elements to achieve sealing; it provides good dust protection but poor water resistance, which ultimately affects the service life of the idler roller. (2) Poor coaxiality of the idler roller shaft. The idler roller shaft is a cold-drawn smooth shaft. The advantage of using such shafts is that their surface roughness and dimensional accuracy can meet the requirements specified in the drawings without any further processing, which makes them convenient to use and saves labor. However, factors such as wear of the dies used in the production of these cold-drawn shafts can lead to unstable dimensional accuracy, with deviations from the specified standards occurring frequently. Additionally, these shafts are prone to bending during transportation, resulting in poor coaxiality. This prevents the proper maintenance of the bearing clearances at both ends of the shaft, thereby increasing the rotational resistance of the idler roller and affecting its service life. (3) Poor coaxiality of the bearing housing. The bearing housings used for the idler rollers are of stamped design; the area where they meet the cylinder shell is not machined, and the bearing housings are welded directly to the cylinder shell. Issues such as irregular shapes of the bearing housings during stamping or uneven end surfaces at the junction with the cylinder shell can lead to misalignment of the bearing housings at both ends after welding to the cylinder shell. This results in reduced bearing clearance, increased rotational resistance, and sluggish rolling performance. 2. Improvement methods: (1) The mechanism of improving idler roller sealing, and the role of sealing is to prevent external dust, moisture, etc. from entering the bearings. Seals can be classified as contact seals and non-contact seals based on whether the seal component comes into contact with the component against which it moves. A touch-type seal is a seal in which the seal makes direct contact with the component that moves relative to it, with no gaps between them; the seal element is in direct contact with the mating component ； Non-contact sealing refers to a type of sealing in which the seal element does not come into contact with the component it moves relative to, and there is an appropriate gap between them; as a result, there is no wear between the seal elements. Given the shortcomings of the original idler seal, a new seal ring design was developed from scratch. This new sealing structure combines touch-type sealing with non-touch-type sealing. The touch-seal is made of oil-resistant rubber, featuring excellent comprehensive mechanical properties, high resilience, and wear resistance. It uses rubber sealing to create a tight fit between the idler shaft, thereby effectively solving the problem of water resistance for the idlers and also preventing dust from entering. The non-contact seal is an axial labyrinth seal, which is divided into an inner seal and an outer seal; a very small curved gap is formed between the inner and outer seals to achieve sealing. The axial labyrinth seal provides good dust protection with low resistance; it can be fitted along the axis, making installation and removal very convenient. Therefore, their organic combination enables the idler rollers to perform their functions of waterproofing and dust prevention more effectively. Since the seals in touch-type sealing make direct contact with the mating components, there is significant friction during operation. As a result, in the initial stage of use, the rolling resistance of these idlers is slightly higher than that of idlers with non-touch-type sealing. However, they have multiple sealing layers and provide better sealing performance; after being used for some time, the idlers become more efficient in rotation. (2) Coaxiality of the progressive idler shaft: Given the instability in the precision of cold-drawn smooth shafts and the inability to compensate for any misalignment that may occur during transportation, round steel is used to manufacture stepped shafts as a substitute for cold-drawn smooth shafts. Processing techniques are employed to ensure the coaxiality at both ends of the shaft, and the bearing mounting areas at these ends are ground. (3) The coaxiality of the idler roller’s bearing housing: To ensure the coaxiality of the two bearing housings, the circumference and end face where the bearing housing meets the cylinder shell are both machined. This approach helps to address issues such as the non-circular shape of the bearing housing or unevenness at the interface with the cylinder shell during stamping, thereby using machining techniques to maintain the coaxiality of the two bearing housings. (4) Improvement of the idler roller processing technique: The sequence of processing the grooves in the axial retaining ring was modified. First, the seal was installed, and an axial play was left in accordance with the specifications; thereafter, the grooves in the axial retaining ring were processed. This approach prevented excessive axial movement, ensuring that the axial play remained no greater than 0.7 mm.