Installation of rolling bearings

One is the sealing issue, and the other is the lubrication issue; once these two problems are resolved, there will be no issues

1. First, check whether the bearing model being used is correct 2. Try replacing the bearings with ones from another manufacturer; it’s possible that there is a problem with the quality of the bearings. 3. Check whether the grade of lubricating oil or grease used is correct. 4. Regularly replace and top up lubricating oil and grease.

If high bearing temperatures and damage occur repeatedly over a period of time on a single device, it is necessary to carefully examine the issue of axial force or expansion force.

It is also necessary to check whether the clearance between the outer ring of the bearing and the inner ring of the bearing, as well as with the spindle, is within an appropriate range

The problem may not necessarily be related to the installation; it could also be due to the quality of the bearings. It is important to choose high-quality bearings, and moreover, the person performing the installation must keep their gloves or hands clean to prevent any contaminants from getting in. Here are the installation precautions: First, before installing the bearing, you must ensure that the installation surface and the installation environment are clean. If foreign objects such as iron shavings, burrs, or dust enter the bearing, it will cause noise and vibration during operation, and may even damage the raceways and rolling elements. 　　Second, it must be carefully cleaned with clean gasoline or kerosene, and then coated with clean, high-quality lubricating grease suitable for high speeds and high temperatures before it can be installed and used. Cleanliness has a significant impact on the lifespan of bearings as well as on vibration and noise levels. Additionally, one thing that must be given special attention to is that fully sealed bearings do not require cleaning or lubrication. 　　Third, care should be taken when selecting grease. Lubrication has a crucial impact on the operation and lifespan of bearings; here we briefly introduce the general principles for selecting grease. Grease is made up of base oil, thickeners, and additives. Greases of different types, as well as different grades within the same type, exhibit significant differences in performance, with varying allowable rotation limits; this factor must be taken into consideration when making a choice. The performance of grease is primarily determined by the base oil; generally, low-viscosity base oils are suitable for low temperatures and high speeds, while high-viscosity ones are suitable for high temperatures and high loads. Thickeners also affect the lubricating properties; the water resistance of the thickeners determines the water resistance of the grease. In principle, greases of different brands cannot be mixed, and even greases with the same thickener can have adverse effects on each other due to differences in additives. 　　Fourth, when lubricating bearings, the amount of grease applied should be moderate. When lubricating bearings, many people think that the more grease applied, the better – this is a common misconception. Excessive grease in the bearings and bearing housings will cause excessive mixing of the grease, resulting in extremely high temperatures. The amount of lubricant filled into the bearing should be 1/2 to 1/3 of the internal space of the bearing; at high speeds, it should be reduced to 1/3. 　　Fifth, certain methods must be followed when installing and removing bearings; care cannot be taken lightly. During installation, do not strike the bearing’s end faces or unloaded surfaces directly; instead, use pressing blocks, sleeves, or other installation tools to apply even force to the bearing. Never transmit force through the rolling elements. Applying lubricant to the mounting surface will make the installation smoother. If the interference is large, the bearing should be placed in mineral oil and heated to 80–90°C before installation; the oil temperature must be kept strictly below 100°C to prevent a decrease in hardness due to tempering effects and to avoid issues with dimensional recovery. When encountering difficulties during disassembly, it is recommended to use a removal tool to pull outward while carefully pouring hot oil on the inner ring; the heat will cause the inner ring of the bearing to expand, making it easier to remove. 　　Sixth, the radial clearance of bearings is not the smaller the better; it is necessary to choose appropriately based on the specific conditions, selecting the most suitable clearance. Not all bearings require the minimum operating clearance; you must select the appropriate clearance based on the conditions. In the national standard 4604-93, the radial clearance of rolling bearings is divided into five groups: Group -2, Group 0, Group 3, Group 4, and Group 5. The clearance values increase in order from smallest to largest, with Group 0 representing the standard clearance. The basic radial clearance group is suitable for general operating conditions, normal temperatures, and common interference fits ； Bearings that operate under special conditions such as high temperature, high speed, low noise, and low friction should be equipped with a larger radial clearance ； For precision spindles and bearings used in machine tool spindles, a smaller radial clearance is advisable ； A small amount of operating clearance can be maintained in roller bearings. Furthermore, for separate-type bearings, clearance is not an issue ； Finally, the operating clearance of a bearing after it is installed is smaller than its original clearance before installation, as the bearing has to rotate under certain loads, and there is also elastic deformation resulting from the bearing’s fit and the applied loads.

The failure rate is high within a short period of time. Calculate the magnitude of the axial force to determine whether the selected bearings are appropriate (width, contact angle, tolerances, clearance)

Choosing the most appropriate clearance is very important, but many people don’t pay attention to it.

Mm, that’s good. . . . . . . .

I think the part that’s difficult to handle during installation is the tightening of the inner and outer rings. The outer ring is fixed by the bearing cover, with a certain amount of expansion clearance left – around ten or so, I’m not entirely sure; this clearance is adjusted using the shims provided with the cover. There are also those with lock nuts on the inner ring; tightening them too much can destroy the original clearance of the bearing, leading to overheating and damage to the bearing. Also, it’s lubricated. Is the oil inlet clogged? What happens to the lubricant when a bearing is damaged?

You might consider trying a bearing heater