Precautions for using graphite copper sleeves

Many people think that graphite copper sleeves are self-lubricating, so graphite copper sleeves are used wherever self-lubrication is needed. In fact, graphite copper sleeves, as a relatively cheap self-lubricating material, have certain limitations in their application. You need to pay attention to the following points to avoid risks:

1. The direction of movement does not match the graphite arrangement. Circumferential and linear motion correspond to different graphite arrangement designs. If the wrong choice is made, the self-lubricating effect will naturally be greatly reduced.

2. Micro-movement conditions. For the graphite copper sleeve to form a complete transfer film, your minimum movement distance must be greater than the distance between two adjacent graphites. Taking circular motion as an example, there is no problem if it is continuous rotational motion, but if it is swinging, the minimum swing angle must be greater than the angle between two adjacent graphites, otherwise a complete transfer film will not be formed, and dry friction areas will appear. , the lubrication effect is poor, and the same is true for linear motion.

3. The speed is too fast. Graphite copper sleeves are generally made of high-strength brass. Under dry friction conditions, the sliding linear speed should not exceed 0.5m/s, and the PV value should not exceed 1.5. Otherwise, it will wear too fast and the use cost will be too high. Under dry friction conditions of graphite copper sleeves, the most suitable movement is low speed and heavy load.

4. Ultra-high temperature working conditions. Graphite will gradually be oxidized at high temperatures above 300°C, and the friction coefficient will increase sharply, which corresponds to a sharp deterioration of the lubrication effect.

5. Vacuum. Graphite will lose its lubrication effect in a vacuum environment because it cannot rely on gas molecules for molecular layer adsorption.

Therefore, the choice of self-lubricating bearings is not limited to graphite, and needs to change based on usage conditions.