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How to lubricate universal joint?
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How to lubricate universal joint?

Views:0     Author:Site Editor     Publish Time: 2021-03-18      Origin:Site

The cross-shaft universal joint is an important part of the automobile power transmission system. From the perspective of automobile structure, for front-wheel drive vehicles the drive shaft uses a constant velocity universal joint, and for rear-wheel drive vehicles, its drive shaft uses two unequal velocity universal joints. General private car owners are very unfamiliar with the lubrication and maintenance of cross-shaft of universal joint, because the universal joints of current car drive shafts are basically disposable accessories.

 

  • Why it is important to lubricate universal joint?

  • How to lubricate universal joint?

  • How to maintain universal joint when it cannot be lubricated?

 

Why it is important to lubricate universal joint?

When the lubrication effect of the universal joint and the bearing bush fails to meet the requirements, a variety of failures will appear. Certain types of bearings that are really difficult to buy have no spare parts and have to be repaired after failure, especially imported bearings. Bearings with minor damage, such as slight water rust during inventory, and slight fretting abrasion during transportation will cause dry friction of the part between the shaft and the bearing bush due to direct contact if the oil pressure is low. At this time, the shaft surface is blue. If the lubricating oil fails or the pressure cannot be built up, the moving surface will lose the protection of the oil film and directly contact for dry friction. When the temperature rises, the alloy layer of the bearing bush will melt, and the bush will be held when the machine is stopped in time. Failure to stop the machine in time will cause more serious damage to the parts.

 

How to lubricate universal joint?

Their cross-shaft lubrication uses high-quality grease, which is compatible with universal joints in the same life span. And the universal joints of some commercial transportation vehicles, especially the existing old trucks, are still repairable.

Cross-shaft of universal joint have to withstand large torsion and alternating loads during work. In the past, the maintenance industry used calcium-based grease commonly known as "butter" to lubricate the universal joint. However, due to the poor toughness of the oil film of calcium-based grease, it is difficult to form a good oil film on the friction surface of the bearing and the journal, which is the cause of the early damage of the universal joint cross shaft needle roller bearing. In addition, due to the design structure of the old universal joint, when the repairman uses a grease gun to add grease to the inner cavity of the cross shaft through the grease nozzle, the resistance to enter the narrow inner oil groove is great because the viscosity of the grease is high. When the grease is pressured, the pressure reducing valve on the opposite side of the oil nozzle will overflow, which makes the repairman mistakenly believe that the bearing has been filled with grease. In fact, in many cases, the grease cannot enter between the needle rollers and reach the end face of the cross journal.

Therefore, the maintenance industry uses gear oil instead of grease to lubricate the universal joint. It is said that after comparative experiments, the lifespan of lubricating the universal joint with gear oil is 2 to 3 times that of lubricating with ordinary butter. However, this also requires special pressurized oiling tools, and the cross shaft needs to be removed and cleaned during the first refueling, which is more troublesome. In addition, the retention of gear oil is not as good as grease, and its lubrication cycle needs to be shortened.

Considering the above reasons, some people use 2# extreme pressure lithium complex grease, which is based on two points. First, its fluidity is better, so that it can easily reach the lubrication part. Second, the grease has good extreme pressure resistance and is suitable for working conditions of universal joint.

 

How to maintain universal joint when it cannot be lubricated?

Universal joint is a transmission output shaft and final drive input shaft in different straight lines. Even if the angle and distance between the two shafts change, power can be transmitted.

In the maintenance of the universal joint, it is very important to ensure the lubrication of the universal joint that the amount of oil injection must be reasonable within the possible range. The fueling hole is blocked, the grease nipple is smashed into the hexagonal deformation or the grease nipple is rusted, the oil circuit will be blocked so that the grease nipple should be replaced in time. During the replacement process, keep the area around the interface clean. It is necessary to prevent the mixing of impurities, dust and sand in the machine.

The intake pressure of the grease gun is insufficient. The high-pressure oil injector is an oil injection device powered by compressed air. The function of pump is to produce high pressure by oil, and then the high pressure is used for oil injection. Pay attention to starting the air compressor before using, and prepare compressed air of about 0.6 MPa. The working principle of refilling grease which is not suitable for lubricating grease is that the thickening agent keeps the oil in the position where needs lubrication. When there is a load, the thickening agent can release the oil to play a lubricating effect.

The universal joint is a special coupling. Due to its structural characteristics, the driving shaft and the driven shaft are not on the same axis. When there is an angle between the axes, the connected two shafts can rotate continuously, and reliably transmit torque and movement.

 

Learn more something about universal joints can know how to lubricate universal joints and how to maintain universal joints. If you want to buy good shaft couplings with reasonable price, FOSHAN HOUZHE TRANSMISSION EQUIPMENT CO., LTD. is your best choice. Whether from quality or price, or delivery time, we can help customers to open up a further and larger market. We have all types of different universal joint, as well as shaft couplings. And if you have any questions, you can contact us or search us online.


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