Protective measures for accuracy of double row ball bearing

The bearing shall be cleaned with gasoline or kerosene before installation, and used after drying, and good lubrication shall be ensured. Double row deep groove ball bearings are generally lubricated with grease or oil. When grease lubrication is used, the grease with excellent functions such as no impurities, oxidation resistance, rust prevention and extreme pressure shall be selected. The filling amount of lubricating grease shall be 30% – 60% of the volume of bearing and bearing box, and shall not be too much. The double row deep groove ball bearing with sealing structure has been filled with grease, which can be used directly by users and can not be cleaned.

When installing the bearing, the bearing must apply equal pressure on the circumference of the ferrule end face to press the ferrule in. It is not allowed to directly knock the bearing end face with hammers and other tools to avoid damaging the bearing. When the interference is small, press the end face of the bearing ring with the sleeve at room temperature, knock the sleeve with a hammer, and press the ring evenly through the sleeve. If installed in large quantities, hydraulic press can be used. When pressing in, ensure that the end face of the outer ring and the end face of the housing shoulder, and the end face of the inner ring and the end face of the shaft shoulder are pressed tightly without clearance.

(1) Measure the size of the shaft and bearing seat hole to determine the matching accuracy of the bearing.

The matching requirements are as follows: the inner ring and the shaft adopt interference fit with an interference amount of 0 ~ + 4 μ M (0 under light load and high precision); Clearance fit is adopted between the outer ring and the bearing seat hole, with a clearance of 0 ~ + 6 μ M (but when the angular contact ball bearing is used for the bearing at the free end, the clearance can also be increased); The roundness error between shaft and seat hole surface is 2 μ M below, the end face parallelism of spacer used for double row deep groove ball bearing is 2 μ M below, the runout of the inner end face and the outer end face of the shaft shoulder is 2 μ Below m; The runout of the shoulder of the bearing seat hole to the axis is within 4 μ Below m; The runout of the inner end of the front cover of the main shaft facing the axis is within 4 μ Below M.

(2) Installation of fixed end front bearing on the shaft:

thoroughly clean the double row deep groove ball bearing with clean cleaning kerosene. For grease lubrication, first inject the organic solvent containing 3% ~ 5% grease into the bearing for degreasing and cleaning, and then fill the quantitative grease into the bearing with an oil gun (accounting for 10% ~ 15% of the bearing space volume); Heat the bearing to raise the temperature by 20 ~ 30 ℃, and install the bearing into the shaft end with an oil press; Press the set sleeve on the shaft and press the bearing end face with appropriate pressure to make it axially positioned; Roll the belt of the spring scale on the outer ring of the bearing and check whether the specified preload changes greatly by measuring the starting torque (even if the double row deep groove ball bearing is correct, the preload may also change due to the deformation of the fit or cage).