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Idler rollers are an important component of belt conveyors, and their internal structure consists of a cylinder cover, idler roller shaft, bearings, bearing housings, seals, retaining rings, etc. It bears over 70% of the resistance during conveyor operation, and is the most widely used and frequently replaced component in belt conveyors. How to extend the service life of idler rollers is a major issue facing production 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 characteristic is that a very small, tortuous gap is created between the inner and outer sealing elements to achieve sealing; this 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 a shaft is that its surface roughness and dimensional accuracy can meet the requirements specified in the drawings without any further processing, which makes it convenient to use and saves labor. However, factors such as wear of the dies used in the production of cold-drawn smooth 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 in turn prevents proper alignment of the bearings at both ends of the shaft, increasing the rotational resistance and thus reducing the service life of the idler roller. (3) Poor coaxiality of the idler bearing seat. The bearing housings used for the idler rollers are of a stamped design; the areas where they meet the cylinder shell are not machined, and the bearing housings are welded directly to the cylinder shell. Issues such as irregular shapes of the bearing housings due to stamping or uneven end surfaces at the points of contact with the cylinder shell can easily 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 rotation. 2. Improvement methods: (1) Mechanism and scheme for improving idler roller sealing. The purpose of sealing is to prevent external dust, moisture, etc. from entering the bearings. Seals can be classified into contact seals and non-contact seals, depending on whether the seal comes into contact with the components that move relative to it. A contact seal is a seal in which the seal makes direct contact with the component that moves relative to it, with no gap between them; the sealing element is in direct contact with the mating part ； 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, no wear occurs between the seal elements. Given the shortcomings of the original idler seal, a new design for the seal ring structure was developed. The internal structure of this new type of idler features a novel sealing design that combines contact sealing with non-contact sealing. The contact seal is made of oil-resistant rubber, which possesses excellent comprehensive mechanical properties, as well as high resilience and wear resistance. It utilizes rubber sealing to create a very tight fit between the idler shaft, thereby effectively solving the problem of water leakage in 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, tortuous gap is created between the inner and outer sealing elements to achieve sealing. The axial labyrinth seal provides good dust prevention performance and low resistance; it can be fitted along the axis, making installation and removal very convenient. Therefore, their organic combination enables the idler rollers to better achieve waterproofing and dustproofing functions. Since the seal elements of a contact-type seal are in direct contact with the mating parts, friction is high during operation; as a result, the rotational resistance of idlers with contact-type seals is slightly higher at the beginning of use. However, they have more sealing layers and provide better sealing performance, so after some time of use, the idlers become more flexible in rotation. (2) Improving the coaxiality of idler shafts: Given the instability in the precision of cold-drawn smooth shafts and the issue that misalignment caused during conveying processes cannot be compensated for, 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 shafts, and the bearing mounting areas at these ends are ground. (3) Improving the coaxiality of the idler bearing seats: To ensure the coaxiality of the two bearing seats of the idler, the circumference and end face where the bearing seats meet the cylinder shell are machined. This approach enables effective resolution of issues such as uneven shapes of the bearing seats during stamping or irregularities at the end faces where they fit with the cylinder shell, thereby ensuring the coaxiality of the two bearing seats through machining. (4) Improvement of the idler roller processing technique: The sequence of operations for machining the axial retaining ring grooves has been modified. First, the seal is installed, and an axial play amount is reserved in accordance with standard requirements; only then are the grooves in the axial retaining ring machined. This approach prevents excessive axial movement, ensuring that the axial play amount remains no greater than 0.7 mm.