Why Can’t the Cardan Shaft Add Oil?

Take the common SWC350BH Cardan Shaft as an example. After calculation, the clearance space in a single bearing sleeve is about 97000mm³without oil injection. As the assembly generally uses a four-point lubrication method, during assembly of the assembly, the operator will pre-lubricate the bearings in the four directions one by one. Some users sometimes encounter the situation that the oil cannot be added. We can analyze this situation from the following aspects:

1. Whether the oil filling hole is blocked. If the grease nipple is smashed into the hexagonal deformation or the grease nipple is rusted, etc., the oil circuit will be blocked, and the grease nipple should be replaced in time. During the replacement process, keep the area around the interface clean and do not allow mechanical impurities, dust, and sand to be mixed in.

2. The intake pressure of the grease gun is insufficient. The high-pressure oil injector is an oil injection device powered by compressed air. It uses the action of a pump to generate high pressure for the oil and uses high pressure for oil injection. Pay attention to starting the air compressor before use, and prepare compressed air of 0.6-0.8 MPa. When connecting, clean the connecting parts and tighten the nut with a wrench to avoid oil leakage.

3. The grease added is not suitable. The working principle of lubricating grease is that the thickening agent keeps the oil in the position that needs lubrication, and when there is a load, the thickening agent releases the oil to play a lubricating effect. If the temperature difference between winter and summer of the environment where the equipment is located is large, pay attention to the timely replacement of seasonal grease to avoid blocking the oil outlet by the butter block. The universal joint shaft assembly generally uses 3# general-purpose lithium grease grease, which is used in different mechanical equipment within the working temperature range of -20℃-120℃. It has good water resistance, mechanical safety, rust resistance and oxidation stability.

4. Misjudgment of operators. Why is it that in some cases, workers will be misjudged that cardan shaft can’t add oil? For example, the oil delivery capacity of common pneumatic high-pressure oiling machine is about 0.85l/min, and the contract of full oil for bearing cavity is 6.85s. Meanwhile, considering the pre oiling and daily oil storage, the actual oil filling time is about 3-5s. Therefore, the replacement time of lubricating grease should be determined according to the specific use.

When you encounter the problem of refueling again, you do not need to panic to determine that the structure cannot be refueled and forcibly refuel the grease. First, check and analyze the above conditions one by one. If the problem cannot be solved, please contact the manufacturer for repair.