Comprehensive calibration method for precision bearing installation accuracy

After the angular contact ball bearing is installed in the main shaft, the verification procedure of the mounting accuracy is as follows (for example, an ordinary lathe with a shaft diameter of 60-100 mm):

(1) Measure the dimensions of the shaft and housing bore to determine the matching accuracy of the bearing. The requirements are as follows:

The inner ring and the shaft adopt an interference fit, the interference is 0~+4μm (0 in light load and high precision); the outer ring and the bearing housing hole adopt the clearance fit, the clearance is 0~+6μm (but the bearing at the free end) When an angular contact ball bearing is used, the clearance can be increased); the circularity error between the shaft and the seat hole surface is less than 2 μm, the end face parallelism of the spacer used for the bearing is 2 μm or less, and the outer end surface of the shoulder shoulder is less than 2 μm; The bearing seat hole shoulder jumps to the axis below 4μm; the inner end surface of the main shaft front cover jumps below 4μm.

(2) Mounting of the fixed end front bearing on the shaft

The bearing is thoroughly cleaned with clean cleaning kerosene. For grease lubrication, the organic solvent containing 3% to 5% grease is first injected into the bearing for degreasing cleaning, and then the grease is filled into the bearing with the oil gun. 10% to 15% of the bearing space volume; heating the bearing to raise the temperature of 20 ~ 30 ° C, the bearing is installed into the shaft end with a hydraulic press; press the set sleeve against the shaft and with the appropriate pressure against the bearing end face to make it axial Positioning; the belt of the spring balance is wound on the outer ring of the bearing, and the method of measuring the starting torque is used to verify whether the specified preload has a large change (even if the bearing is correct, the preload is also due to the deformation of the fit or the cage) The possibility of change).

(3) Mounting the bearing-shaft assembly into the seat hole

The seat hole is heated to raise the temperature by 20 to 30 ° C, and the bearing-shaft assembly body is installed into the seat hole by continuous gentle pressure; the front cover is adjusted so that the fastening amount of the front cover is 0.02 to 0.05 μm, and the outer end surface of the bearing seat is Benchmark, the head of the dial gauge is in contact with the surface of the journal, and the shaft is rotated to measure its jitter, and the required error is below 10 μm; the dial gauge is positioned on the shaft, and the head is in contact with the inner surface of the rear seat hole to rotate the shaft To measure the coaxiality of the front and rear seat holes of the bearing housing.

(4) The free end bearing is selectively placed at a position where the deviation may be offset, and is mounted to the bearing position of the bearing housing to offset the roundness deviation and the coaxiality deviation between each other as much as possible.