The assembly method of TIMKEN bearings is to sort the inner ring, outer ring and rolling elements in size, and through selection to ensure that they have the required radial clearance or width after assembly. One of the main processes in the assembly process of TIMKEN bearings is the selection of matching sleeves. First, the raceway diameters of the rings must be selected and grouped, and then the inner ring, outer ring and rolling elements of the various groups are according to the clearance required by TIMKEN bearing Or the width tolerance fits together to become a "set" TIMKEN bearing assembly method. During the processing of bearing rings, for various reasons, the raceway size will be too scattered or the tolerance zone center will be offset, or even exceed the tolerance zone These problems will reduce the matching rate.
Bicycles use rubber-sealed deep groove ball bearings. Such bearings are most afraid of knocking (needle roller bearings and large bearings are slightly more resistant to knocking), and heating installation methods cannot be used, but because bicycles The interference of the bearing is very small, even if the Qinghao bearing hub can be put into the bearing by hand, it is relatively safe to use a rubber hammer to knock in, but the backing of the pusher needs to have a very flat surface. The best way is to use static pressing, such as pressing in a vise.
Another reason for the damage as high as 16% is that the improper assembly, wrong or violent loading method has caused those bearings to be hit hard on the smooth surface of the bowl when they are loaded.
In order to allow the bearing to tighten the shaft and prevent the friction phenomenon of the shaft sleeve (this phenomenon will instantly generate high temperature on the high-speed rotating machinery, causing the lubricating oil to dry up and even lead to thermal expansion, resulting in shutdown), so the inner bearing Dang and outer bowl (also known as bearing box in industry) use a kind of "interference" phenomenon. In layman's terms, the shaft is larger than the inner pan, or the outer bowl is larger than the load. This kind of interference requires a lot of force to install. However, such an installation requires great force to strike the bearing, which will cause damage to the bearing during the percussion process. Therefore, large bearings in the industry usually use heating, hydraulic jacking and other methods.
For this reason, before matching, the stock TIMKEN bearing rings should be selected for preliminary selection, and the size of the raceway should be grasped, and according to the size of the rolling elements, the matching parts (inner ring or outer ring) should be submitted to the grinding work area in time for processing Tolerance order form. After receiving the tolerance order form, the grinding work area should strictly follow the order tolerance dimensions for processing. In this way, the matching rate of TIMKEN bearing assembly can be improved.
TIMKEN bearings are precision parts, and the use of TIMKEN bearings must be carried out accordingly. No matter how high performance bearings are used, if they are used improperly, the expected high performance will not be obtained.
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(1) Keep the bearing and its surroundings clean.
Even small dust invisible to the eyes can have a bad effect on the bearing. Therefore, keep the surroundings clean to prevent dust from entering the bearing.
(2) Use it carefully.
A strong impact on the bearing during use will cause scars and indentations, which may cause accidents. In severe cases, it will crack or break, so be careful.
(3) Use appropriate operating tools.
Avoid replacing with existing tools, you must use appropriate tools.
(4) Pay attention to the corrosion of the bearing.
When handling TIMKEN bearings, sweat on your hands can cause rust. Pay attention to the operation with clean hands, it is best to wear gloves as much as possible.
(5) The press pushes the bearing, working smoothly and reliably, without damaging the machine and bearing. The press has manual push, mechanical or hydraulic press.
Note: The pressing point of the press should be on the center of the shaft and should not be biased.
(6) Percussion method: The percussion force is generally applied to the inner ring of the bearing. The percussion force should not be applied to the rolling elements and cage of the bearing. This method is simple and easy to implement, but it is easy to damage the bearing. When the bearing is located at the end of the shaft At the same time, use a copper rod smaller than the inner diameter of the bearing or other soft metal materials against the shaft end, add a cushion block under the bearing, and tap it with a hammer to remove it. When applying this method, attention should be paid to the proper placement of the pad and the correct focus point.
(7) Hot dismantling method: used to dismantle tightly fitted TIMKEN bearings. First, pour the oil heated to about 100°C on the bearing to be dismantled with an oil can, and after the bearing ring is heated and expand, the bearing can be pulled out with a puller.
Note: First, install the puller on the bearing to be removed and apply a certain tension; before heating, wrap the shaft with asbestos rope or thin iron plate to prevent the shaft from swelling due to heat, otherwise it will be difficult to remove. When removing the bearing from the bearing housing hole, only the bearing housing hole can be heated, not the bearing; when pouring oil, the oil can should be smoothly poured on the bearing ring or rolling element, and an oil basin should be placed under it , Collect the running hot oil to avoid waste and burns; the operator should wear asbestos gloves to prevent burns.