Matching of machine tool spindle bearing, shaft and bearing seat

In order to give full play to the performance of the machine tool spindle bearing, the inner ring and the shaft and the outer ring and the bearing seat must be properly matched. Insufficient interference of the mating surface during operation will cause misalignment between the rolling elements and the shaft or bearing seat. This phenomenon is called peristalsis. Creeping of the mating surface will cause abnormal temperature rise, wear and wear debris entering the inside of the bearing, causing early damage or vibration and other problems, causing the bearing to fail to fully perform its performance. The best way to prevent creep is to perform an interference fit on the inner and outer rings. However, in order to facilitate the actual installation and disassembly, the inner ring or the outer ring is usually fitted with a clearance fit on one side. However, due to limited conditions, there may be situations where the above operations are not allowed, so the matching of the bearing should be fully considered with the relationship between the shaft and the bearing seat, and other conditions will be determined. Please refer to Table 8.1~8.3 for the coordination of common use conditions (inner ring rotation) of precision bearings for machine tools. Table 8.1 Recommended matching bearing types with shaft Shaft diameter (mm) Bearing accuracy class 5 Class 4 / Class 2 exceeds the following target matching shaft tolerance Target matching shaft tolerance Angular contact ball bearing 10 18 0~2T h4 0~2T h318 50 0 ~2.5T h4 0~2.5T h350 80 0~3T h4 0~3T h380 150 0~4T js4 0~4T js3150 200 0~5T js4 0~5T js3 Cylindrical roller bearing (cylindrical bore) 25 40 − js4 − js440 140 − k4 − k3 140 200 − k4 − k3 Main shaft thrust bearing full shaft diameter 0~6L h4 0~6L h4 Ball screw support bearing full shaft diameter 0~10L h5 0~10L h5 Table 8.2 Recommended fit with bearing seat (fixed Side) Note) The number suffix L in Table 8.1~8.3 is the clearance, and T is the interference. Bearing housing inner diameter (mm) Bearing accuracy class 5 class 4 class 2 Hole tolerance angular contact ball bearing 18 50 0~3L JS4 0~3L JS350 120 0~4L JS4 0~4L JS3120 180 0~5L JS4 0~5L JS3180 250 0~6L JS4 0~6L JS3 cylindrical roller bearing (cylindrical hole ) Full bearing inner diameter ±0 K5 ±0 K5 spindle thrust bearing full bearing inner diameter 30L~40L K5 30L~40L K5 ball screw support bearing full bearing inner diameter 10L~20L H6 10L~20L H6 Table 8.3 and bearing seat recommendation Matching (free side) bearing type Bearing housing inner diameter (mm) Bearing accuracy class 5 Class 4 Class 2 exceeding the following target matching bearing housing hole tolerance target matching bearing housing hole tolerance Angular contact ball bearing 18 50 6L~10L H4 6L~10L H350 120 8L~13L H4 8L~13L H3120 180 12L~18L H4 12L~18L H3180 250 15L~22L H4 15L~22L H3 Cylindrical roller bearing (cylindrical bore) Full bearing inner diameter ±0 K5 ±0 K4 ball screw support Bearing full bearing housing inner diameter 10L~20L H6 10L~20L H6