In order to solve the lubrication problems of high temp […]
In order to solve the lubrication problems of high temperature, low speed, heavy load, dust, water flushing and impact vibration in mechanical equipment, oil-free self-lubricating bearing is selected.
1. The structure of the bearing self-lubricating bearing is to develop holes with proper size and orderly arrangement on the metal friction surface of the bearing matrix, and embed molybdenum disulfide, graphite, etc. to make a composite self-lubricating sliding block, which is embedded in the metal sleeve. The friction area of the solid lubricant is 25-65%. The solid self lubrication slide can work normally at 280 ℃. However, due to its low mechanical strength and weak bearing capacity, it is easy to deform. If it is inlaid in the metal hole and groove, this defect can be restrained. The metal part plays the role of bearing and the self lubricating sliding block plays the role of lubrication.
The lubrication mechanism of the self-lubricating bearing is that in the sliding friction process between the shaft and the sleeve, a part of the self-lubricating material molecules transfer to the metal surface of the shaft, fill up the micro non-plane, and form a relatively stable solid lubrication film, resulting in the friction between the solid lubricating films and preventing the adhesion wear between the shaft and the sleeve. This reasonable combination combines the complementary advantages of copper alloy and non-metallic antifriction materials. It is especially suitable for oil-free, high-temperature, high-load, low-speed, anti-fouling, anti-corrosion and strong radiation environment, as well as the special working conditions in which lubricating grease cannot be added due to water or other solutions.
2. The area ratio of self lubrication slide block to surface area of self lubrication slide block is related to the running speed and bearing strength, and the running speed is low; if the bearing strength is large, the metal area should be larger. For example, the area of the self lubricated slide block of the walking wheel bearing of the ingot trolley is about 25%, and the bearing of the spindle pulling mechanism should be fully lubricated, and the bearing strength is not large. The area of the self lubricating sliding block is about 65%.
3. Technical requirements for bushing material: self lubricating bearing bushing shall be made of alloy copper, with high hardness and heat treatment generally, and its hardness shall not be lower than hrc45.
4. The geometric shape and inlay requirements of self lubricating slide block. There are two types of self lubrication slide block: cylindrical and rectangular. According to the size of self lubrication area, column shape can be used, otherwise rectangle can be used. No matter what shape, it must be inlaid firmly to prevent falling off during operation.
5. The linear expansion coefficient of the self lubricated slider is about 10 times that of the steel. In order to adapt to the change of bearing temperature, the clearance between shaft and bushing is increased from 0.032 ~ 0.15mm to 0.45 ~ 0.5mm from the original four stage dynamic fit (D4 / DC4). The self lubricating sliding block protrudes 0.2 ~ 0.4mm from the lining metal on one side of the friction pair. In this way, the bearing will be fully lubricated during the initial running in period, and the consumption of power driving power will be reduced.