How to keep the accuracy of automobile bearing unchanged?

The basic protection measures of automobile high-precision bearings are to ensure the accuracy of bearings. Before installation, bearings should be cleaned with gasoline or kerosene, and then used after drying, and good lubrication should be ensured. Automobile Bearings generally adopt grease lubrication or oil lubrication. When grease lubrication is used, the grease with no impurity, anti-oxidation, anti rust, extreme pressure and other functions shall be selected.

The filling amount of grease is 30% – 60% of the volume of bearing and bearing box, which should not be too much. The automobile bearing with sealing structure has been filled with grease, which can be directly used by users and can not be cleaned again.

When installing the bearing, it is necessary to apply equal pressure on the circumference of the end face of the ring to press the ring in. It is not allowed to directly knock the end face of the bearing with a hammer, so as to avoid damaging the bearing. In the case of small interference, the end face of bearing ring can be pressed with sleeve at normal temperature, and the sleeve can be knocked with a hammer, and the ring can be pressed in evenly through the sleeve.

If a large number of installation, you can use the hydraulic press. When pressing in, ensure that the outer ring end face and the shell shoulder end face, the inner ring end face and the shaft shoulder end face are pressed tightly, and there is no gap.

(1) Measure the size of the shaft and bearing housing hole to determine the fitting accuracy of the bearing. The matching requirements are as follows: the inner ring and the shaft adopt interference fit, the interference amount is 0 ~ + 4 μ m (0 in light load and high precision); the outer ring and bearing housing hole adopt clearance fit, the clearance is 0 ~ + 6 μ M (but when angular contact ball bearing is used in the bearing at free end, the clearance can also be increased); the roundness error between the shaft and the seat hole surface is less than 2 μ m, the end face parallelism of the spacer used in automobile bearing is less than 2 μ m, the runout of the inner end face of the shaft shoulder is less than 2 μ m, the runout of the bearing housing hole shoulder to the axis is less than 4 μ m, and the runout of the inner end of the spindle front cover to the axis is less than 4 μ M.

(2) Installation of fixed end front bearing on the shaft: clean the automobile bearing thoroughly with clean cleaning kerosene. For grease lubrication, the organic solvent containing 3% – 5% grease is injected into the bearing for degreasing and cleaning, and then the quantitative lubricating grease is filled into the bearing with oil gun (10% ～ 15% of the bearing space volume); heating the bearing to make the temperature rise 20-30 ℃, install the bearing into the shaft end with an oil press; press the tightening sleeve on the shaft and press against the bearing end face with appropriate pressure to make it axially positioned; coil the belt of the spring scale on the outer ring of the bearing, and check whether the specified preload has a large change by measuring the starting moment (even if the double row deep groove ball) The bearing is correct, but the preload may also change due to the deformation of the fit or cage).