After installing the NACHI main shaft bearing, check whether it can operate normally through the test run. Especially in the case of grease lubrication, in order to ensure that the grease is evenly distributed inside the bearing, a sufficient running-in operation is required. The general operation inspection steps are as follows: a. Confirm whether there is contact between the shaft and the bearing seat, or the cover, and whether the clearance is consistent. b Manually rotatable machinery, first manually confirm whether there is abnormal noise and whether there is blockage. c For large machines that cannot be rotated manually, try to start running at a low speed, and confirm the above item b. d If the above confirmation is not abnormal, you can increase the rotation speed in turn until the normal rotation speed, and confirm whether the temperature increase is in accordance with the normal state. e Continue to carry out a long test run to confirm whether there are loose bolts, nuts, oil or grease leakage, and noise. After the test run, try to extract the lubricant to confirm that no foreign matter enters. f After confirming the above items, enter the working state. The main reasons for disassembling NACHI machine tool spindle bearings are periodic disassembly or mechanical failure. When disassembling, it is hoped that the mechanical state at this time can be confirmed as a reference for future improvement. Especially at the time of failure, the main points of solving the failure can be found in the disassembled state, and the following investigations are required. a Whether there is any abnormality in the installation state of the bearing b The residual amount of lubricating oil and grease, the degree of pollution (samples are taken in advance) c The fitting state of the inner ring and the outer ring d The failure state of the bearing In addition, when disassembling, please check the following points in advance analysis. a Bearing disassembly method b Matching conditions c Disassembly tool. [Clearance adjustment of cylindrical roller bearing with tapered bore] The internal clearance of cylindrical roller bearing with tapered bore can be adjusted by the thickness of the spacer. The sequence of operations is as follows: a Confirm the conical portion of the shaft. 80% contact is required for the liquid to be applied to the cone. b Gently put the inner ring with rollers into the tapered part of the shaft (Fig. 9.8) c Put the outer ring into the horizontal fixed shaft d Place the measuring end of the dial indicator at the center of the outer diameter of the outer ring e Press the outer ring from above, left and right Turn to zero the dial indicator. f Press the outer ring upward at the 180-degree symmetrical position (just below) of the measuring end, and turn left and right to read the maximum value (Figure 9.9) g Rotate the shaft about every 30 degrees, measure the radial clearance, and determine the average value of the measured value. For ΔRh, use a block gauge to measure the length to the end face of the inner ring and the shaft shoulder (Fig. 9.10). i Change position The measured values u200bu200bof 5~6 positions are averaged, and L'j is determined by using the thickness dimension of the spacer block by formula 9.3. (Equation 9.3) L' : Average spacer thickness measured in step i R : Measured radial clearance: Target radial clearance after installation u0026#1048655; e : Outer ring shrinkage D : Outer ring outer diameter (mm)De : inner diameter of outer ring (mm)Dh : outer diameter of housing (mm)u0026#1048647; : interference of outer ring k Correct the thickness dimension of spacer l Take the inner ring with rollers from the shaft At this time, it is necessary to avoid vigorously striking the inner ring. It can be easily removed using a dedicated removal tool. m Install the spacer and NACHI bearing on the shaft. n Measure the radial clearance again and confirm that the radial clearance has reached the target value (Fig. 9.11). 9.2.4 Confirmation after installation Use the method exemplified in 5-3 Measurement of Preload (P.14) to confirm whether or not the predetermined preload is applied.