Bearing vibration damage should pay attention to several problems

Generation of vibrations in bearings Generally speaking, rolling bearings do not generate noise by themselves. What is commonly perceived as "bearing noise" is actually an acoustic effect in which the bearing vibrates directly or indirectly with the surrounding structure. This is why many times a noise problem can be viewed as a vibration problem involving the entire bearing application.

(1) Vibration caused by the change in the number of loaded rolling elements: when a radial load is loaded on a bearing, the number of rolling elements that carry the load will change slightly during operation, which causes a shift in the direction of the load . The resulting vibrations are unavoidable but can be mitigated by axial preloading on all rolling elements (does not apply to cylindrical roller bearings).

(2) Local damage: Due to operation or installation errors, a small part of the bearing raceways and rolling elements may be damaged. During operation, rolling over damaged bearing components generates specific vibration frequencies. Vibration frequency analysis identifies damaged bearing components. This principle has been used in condition monitoring equipment to detect bearing damage. To calculate bearing frequencies, see the calculation program "Bearing Frequencies".

(3) Accuracy of related parts: In the case of close fit between the bearing ring and the bearing seat or drive shaft, the bearing ring may be deformed by matching the shape of the adjacent parts. If deformation occurs, vibrations may occur during operation.

(4) Pollutants: If operating in a polluted environment, impurities may enter the bearing and be crushed by the rolling elements. The degree of vibration generated depends on the number, size and composition of the crushed foreign particles. Although the typical frequency pattern is not generated, an audible noise is audible.

The reasons for the noise of rolling bearings are more complicated, one of which is the wear of the mating surfaces of the inner and outer rings of the bearing. Due to this wear, the matching relationship between the bearing and the housing, and the bearing and the shaft is destroyed, causing the axis to deviate from the correct position, and abnormal noise occurs when the shaft moves at high speed. When the bearing is fatigued, the metal on its surface will peel off, which will also increase the radial clearance of the bearing and produce abnormal noise. In addition, insufficient lubrication of the bearing, the formation of dry friction, and the cracking of the bearing will produce abnormal noises. After the bearing is worn and loose, the cage is loose and damaged, and abnormal noise will also occur.

Bearings are used in daily life, and we need to pay attention to their use. Let's take a look at the nine things we need to pay attention to.

1. The riveted parts in the harvester, such as the moving knife assembly, are generally made of cold extrusion, and should not be heated during riveting, such as heating will reduce the strength of the material. After riveting, a forming punch should be applied to strengthen the firmness of the blade and the blade.

2. Vulnerable parts, especially pins, tablets, sleeves and horns, cannot be replaced and repaired by adding more butter during maintenance. If the worn parts are used for a long time, other mechanical life will be shortened.

3. Shaft repair without balancing machine. When repairing various shafts that need to be balanced, a thrust bearing can be installed at one end of the shaft, clamped on the three claws of the lathe, and the other end can be supported by a sharp point. If the lathe is short, a center frame can be used. Clamp the SKF bearing mounted on the shaft at the other end and correct the balance. But when counterweight, use screws to tighten, try not to use electric welding to counterweight.

4. In the maintenance process, due to the variety of materials and types of bearings, it is not easy to purchase, and waste shafts can be used for processing. At present, most of the shafts in our country are mainly made of 45# carbon steel. Oxygen and earth furnace heat the required parts to red and black and place them in salt water, depending on the demand.

5. When processing sleeve parts, try to pull the oil groove in the sleeve hole as it is very difficult to refuel some parts of the harvester. Where it is difficult to refuel, butter and heavy oil can be used, except for nylon sleeves. Do not use cast iron, copper or aluminum for the parts where nylon sleeves are used, because the nylon sleeves can withstand a certain impact without deformation.

6. The key and keyway on the pulley and shaft should be repaired to ensure that the size does not change to advance. The size of the key must not be increased, otherwise the strength of the shaft will be affected. The keyway on the shaft can be repaired by welding fillers and milled in the opposite direction of the old key A keyway, the keyway on the pulley can be inserted by the method of inserting (transition fit), after inserting, use the countersunk head screw to tap in the sleeve to tighten the key.

7. The maintenance of the hydraulic part of the harvester is to remove the distributor and reducing valve, etc., and use the air pump to pressurize each pipe fitting. When the hydraulic oil is loaded for the second time, it should be filtered and exhausted. The seals should be removed and replaced with new ones.