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As the screw compressor operates for an extended period of time, the bearings inevitably wear out, which leads to increased axial and radial movement of the screws. This change results in gaps forming between the screws, as well as between the screws and the main housing and its front and rear end surfaces. When bearing wear and the clearance between the main unit exceed the allowable limits, serious consequences may occur. Firstly, friction occurs between the screw inside the machine and its front and rear end surfaces, which leads to a sharp increase in the motor’s load. A severe consequence of this is that the screw may get stuck, or even the entire machine could be damaged. If the motor protection system does not respond properly or fails, it may result in the motor burning out. From this, it can be seen how important bearings are. Based on their function, bearings can be divided into rolling bearings and sliding bearings, with rolling bearings being commonly used in screw compressors. I. Function of rolling bearings: Rolling bearings are used to bear radial forces, while axial forces are handled by four-point contact ball bearings. The bearings used in York screw compressors are capable of operating continuously without friction for 100,000 hours; this helps to reduce energy consumption and the reliance on lubricating oil, thereby facilitating the proper operation of the compressor unit. II. Composition of rolling bearings: Rolling bearings are typically composed of components such as the outer ring, inner ring, rolling elements, and retainers. They feature low frictional resistance, low power consumption, high mechanical efficiency, a compact structure, the ability to handle large loads, minimal wear, the capability to sustain both radial and thrust loads simultaneously, and a long service life. III. Common faults of rolling bearings: 1. The reasons for excessively high bearing temperatures may include lubricant quality that does not meet requirements or deterioration of the lubricant, excessive viscosity of the lubricant, overly tight bearing assembly, rotation of the bearing rings on the shaft or within the housing, excessive load, and fragmentation of the bearing cage or rolling elements. 2. Bearing noise: Rolling bearings are allowed to produce slight operating noises during use; however, if the noise is too loud, or if there are abnormal sounds or impacts, it indicates that the bearing is faulty. The reasons for noise generation in rolling bearings are complex; one of them is the wear of the mating surfaces between the inner and outer rings of the bearing. Due to this wear, the fit between the bearing and the housing, as well as between the bearing and the shaft, is compromised, causing the axis to deviate from its correct position and resulting in abnormal noises when the shaft is in motion at high speeds. When a bearing becomes fatigued, the metal on its surface peels off, which also increases the radial clearance of the bearing and causes abnormal noises. Furthermore, insufficient bearing lubrication that leads to dry friction, as well as broken bearings, can all cause abnormal noises. 3. Bearing wear is a common issue, primarily caused by the mechanical properties of the metal used in the shafts. Although metal is hard, it cannot return to its original shape once deformed; as a result, its resistance to impact and fatigue is low, which makes it prone to adhesive wear and fatigue wear. Therefore, when a compressor experiences high temperatures or unusual noises, this could be the underlying cause. IV. Maintenance of rolling bearings: Rolling bearings usually develop problems in screw compressor units when their operating time approaches 100,000 hours. Gonglenghui recommends replacing them with brand-new bearings to ensure that the bearings can maintain their original performance in the compressor unit. If problems arise due to a short operating time of the rolling bearings, it is necessary to inspect the interior of the compressor; the damage to the bearings may be caused by other factors or by an incorrect bearing model. Therefore, it is advised to purchase bearings in accordance with the manufacturer’s guidelines, and avoid using bearings of unknown origin to prevent damage to the compressor and disruption in its operation.