What are the five conditions for choosing self-lubricating bearings?

Self-lubricating bearings can effectively solve lubrication problems, such as high temperature, low speed, high load, heavy dust, washing, impact and vibration of mechanical equipment. The choice of self-lubricating bearing material is very important. The lubrication mechanism of self-lubricating bearing material is that some molecules in the self-lubricating bearing material will move to the metal surface of the shaft in the process of sliding friction between the shaft and the shaft sleeve, and fill irregular tiny spots. The relatively stable layer of the solid lubricant causes friction between the solid lubricants and prevents wear of the adhesive between the shaft and the sleeve. So how should self-lubricating bearings be selected? The following is a small edition of Hangzhou self-lubricating bearings to know about it.

1. Bearing structure self-lubricating bearing is a composite self-lubricating block, embedded in the metal sleeve, the method is to drill an appropriate size of the hole on the metal friction surface of the bearing matrix, and then embed molybdenum disulfide, graphite, etc. It is made of a composite self-lubricating block. The friction area of bearings and solid lubricants is 25-65%. Solid self-lubricating blocks perform well at temperatures up to 280°C. But, because of its low mechanical strength, bearing capacity is weak and easy to deformation, thus can be embedded into the groove of the holes or metal to suppress the defects, and self-lubricating block to lubricate the metal part of the support load of this type of self-lubricating bearing lubrication mechanism is a kind of relatively stable solid lubricating film, some of the self-lubricating material molecules in the process of sliding friction between shaft and shaft sleeve moved to the axis of the surface of the metal, thus fill the small irregularity. Generates friction between solid lubrication films and prevents wear of the adhesive between the shaft and the shaft sleeve. This rational combination combines the complementary advantages of copper alloy and non-metallic friction reducing materials, oil-free, high temperature, high load, low speed, anti-fouling, corrosion resistance and migration in highly radioactive environments. Especially suitable for amplitude. It is used under special operating conditions by dipping it into a solution such as water and does not require the addition of grease.

 

2. The area of the self-lubricating block is related to the working speed and pressure resistance of the self-lubricating block. Slow operation, high pressure resistance, and the area of metal as large as possible. For example, the self-lubricating block of the walking wheel bearing of the spindle clutch car accounts for about 25% of the area, and the spindle bearing of the pulling mechanism needs to be fully lubricated, and the pressure bearing capacity is not large. Self-lubricating blocks occupy about 65% of the area.

 

3. Technical requirements of bushing materials bushing must be made of alloy copper, the bushing has a high hardness, usually need to undergo heat treatment, the hardness of HRC45.

 

4. Self-lubricating block shape and Mosaic requirements. There are two types of self-lubricating blocks, cylindrical and rectangular, which can be either cylindrical or rectangular depending on the area occupied. Regardless of its shape, it must be securely mounted so that it will not fall off during operation.

 

The linear expansion coefficient of the self-lubricating block is about 10 times that of steel. To accommodate bearing temperature changes, the clearance between the shaft and the bushing increases from the original 4-step dynamic fit of the metal part (D4 / DC4) from 0.032 to 0.15 mm to 0.45 to 0.5 mm. The self-lubricating block protrudes 0.2-0.4mm from the bushing metal on one side of the friction pair. In this way, the initial running-in period of the bearing operation is fully lubricated, thus reducing the consumption of power transmission.

 

The above is all the content about how to choose self-lubricating bearings. Thank you for your understanding and support!

 


Post time: Feb-20-2021