Installation method of rolling bearing

Installation method of rolling bearing

Shaft and housing hole maintenance

Before the installation of the rolling bearing, the shaft, housing hole, end cover and other parts that are matched with it shall be strictly inspected; for the used shaft and housing hole, full accuracy inspection shall be performed; unqualified parts shall be repaired. Or replace it. Otherwise, assembly is not allowed.

Shaft maintenance

Check the journal eccentricity, bending and diameter variation (ellipticity), place the shaft on the top of the lathe, or place it on a cast iron plate supported by V-shaped iron. Contact the bearing with the dial indicator pointer. , and then slowly rotate the shaft, observe the swing of the dial gauge pointer on the journal.

If the shaft rotates one revolution, the pointer only swings toward one and then returns to the original position. This means that the shaft has eccentricity or bending. The amount of eccentricity and bending is half of the dial indicator's swing value; if the shaft rotates one revolution, After the table pointer swings twice, it returns to its original position, indicating that the journal is elliptical.

The difference between the maximum and minimum values ​​of the dial indicator index is the ellipticity value. When the eccentricity and bending of the shaft are greater than the specified value, the shaft is straightened or milled. The ellipticity value should generally not exceed 1/2 of the journal size tolerance. Too big ones should be welded, car, milled and repaired.

When testing the surface roughness of the journal, when the journal has burrs or bumps, it should be wiped off with fineness and then polished with a fine emery cloth. Verify journal shoulder perpendicularity and fillet shoulder radius. The perpendicularity of the shoulders should be close to the shoulders of the shaft at right angles to make them close together. Then they can be checked by light or sunlight. For example, even light leakage or no light leakage indicates that the shoulders are vertical.

The fillet radius at the base of the shoulder can be checked with a round corner template. If the radius of the fillet is too large, the shoulders of the bearing and the shaft are not tight and vibration is easily caused during use. If the radius of the fillet is too small, the strength of the shaft is affected. Therefore, the radius of the shoulder of the shoulder should be less than the radius of the inner ring of the bearing. Generally, it should be 1/2 of the radius of the inner ring of the bearing to ensure that the bearing is close to the shoulder.

Check journal size

Micrometer or dial indicator test can be used. When the journal wears seriously, the size is smaller than the specified fitting requirements, and the bearing inner diameter is loose, the bearing journal shall be repaired. The general repair method has the following four: Inserts When the journal is thick (greater than 40mm), the journal can be turned off by 10 to 15mm, and then the prepared sleeve is placed in the hot oil to be heated, and the hot-set method will be used.

Set up on the thin journal of the car, and finally finish the outer diameter of the insert so that the size meets the requirements of the inner diameter of the bearing. The welding allowance will be first polished to a rough shaft, cut off 0.3-0.5mm, and then welded by gas welding or welding. After welding, the shaft journal wheel is ground to the specified size on the machine tool.

To prevent bending of the shaft during repair welding, symmetric balanced reweld welding with reverse deformation can be used. Chromium plating and low temperature iron plating surface are not self-propelled. When the journal size wears lightly, or if the size of the gauge exceeds the difference after processing, this method can be used to apply plating and grinding to repair.

Knurled flower punching When the journal size wear is slight or the machining is slightly out of tolerance, a small number of small holes can be made evenly in the circumference of the journal, and the size of the journal can be increased by the convex portion of the edge of the small hole, or on the lathe With knurled knife on the journal knurled, increase the size of the journal, with the bearing with the installation. This method can only be used as an immediate emergency measure and is generally not suitable for use.

Overhaul of the housing hole

Check the ovality and cylindricity (taper) of the housing hole. For the integral housing hole, check with an inner diameter micrometer or vernier caliper. The split housing hole must be put together with the upper and lower parts, tightened with bolts and tightened tightly. Posted after inspection.

When verifying that the squareness of the housing bore and the shaft stop shoulder is not perpendicular to the rotation centerline, the load is likely to be concentrated on the local rolling elements of the bearing, causing uneven force distribution, resulting in peristaltic motion and stressing the raceway. Large, leading to deformation, affecting life.

The available light gap method can be used to check the shoulder of the shoulder with a right angle, and the dial indicator can also be used to measure the runout of the shoulder surface of the shoulder.

Huatao Bearings included Rolling Bearings, Thrust Bearings, Slewing Bearings, Joint Bearings. They are widely used in Industrial Gearboxes, Electric Motors, Industrial Rollers.