What is axle box device? How to maintain it?
The axle box device is a component of coupling wheel set and bogie frame or two axle car body, which is sleeved on the axle journal on the railway locomotive and vehicle.
The axle box device is a component of coupling wheel set and bogie frame or two axle car body, which is sleeved on the axle journal on the railway locomotive and vehicle. Its function is to transfer the weight and load of the car body to the wheel set, lubricate the journal, reduce the friction and reduce the running resistance. According to the type of bearing used, the axle box device can be divided into two types: sliding bearing axle box device and rolling bearing axle box device. In the early years, the rolling bearing axle box device was used in rolling stock. At the beginning of the 20th century, the rolling bearing axle box device was tried out, and now it has gradually replaced the sliding bearing axle box device. Rolling bearing axle box devices have been used in passenger cars, diesel locomotives and electric locomotives, and in freight cars.
Sliding bearing axle box device
The axle box of the freight car is installed on the outside of the wheel and consists of the axle box body, axle box cover, bearing bush, bearing pad, oil lubrication device and dust-proof plate. The axle box on the driving wheel and guide wheel of the steam locomotive is installed on the inner side of the wheel, and the oil box is used to supply oil to lubricate the journal. Other parts are the same as the above parts.
Axle box body
Bearing load, storage shaft oil components, used to contain journal and other parts. In the early days, it was made of cast iron, and generally made of cast steel. The axle box body not only transfers the load from the frame to the journal, but also bears the load supported by the jack from the bottom when repairing and replacing the bearing, so it should have enough strength. The axle box body and the axle box cover must be tightly fitted to avoid oil leakage and prevent rain and dust from entering. There are two types of axle box body: guide frame type and non guide frame type.
The component that the bearing bush rubs against the journal and transfers all the load borne by the axle box body to the journal is composed of the bush body and a layer of antifriction alloy on its surface. The early tiles were cast with copper alloy, and later steel backing copper lining was used. In China, ductile iron was used. The antifriction bearing alloy, commonly known as white alloy, used in Chinese railway vehicles is lead antimony tin alloy. The alloy is easy to scrape and grind, has good compression resistance, antifriction and heat resistance, and is easy to cast. In recent years, in order to prevent the early scrapping of the bearing bush and avoid burning the shaft, the front end of the bearing bush of the freight car with the capacity of more than 50 tons is inlaid with a plastic head.
The parts installed between the axle box body and the bearing shell to transfer the load. Its upper surface is arc-shaped to improve the load distribution on the surface of white alloy. The lifting height of the jack can be reduced by removing the base plate before replacing the bearing bush.
Oil lubrication device
A device that supplies shaft oil between the bearing shell and the journal to reduce friction. The utility model is composed of an oil coil, a wooden front sleeper and a rear baffle plate, which is installed in the axle box body. The coil is filled with shaft oil (lubricating oil) and contacts the lower part of the journal. When the vehicle is running, the journal rotates, bringing the axle oil between the bearing bush and the journal, forming an oil film, which changes the dry friction into liquid friction. In the early days, oil coils were made of cotton wool, some of them were made of oil brushes. In recent years, China's railway vehicles have switched to foam plastic wrapped with towel covers. The function of the wooden front pillow is to replace the oil roll at the outer end of the journal and prevent the oil roll from moving out. The back baffle is used to prevent the oil from overflowing from the rear end of the journal.
Its function is the same as the axle box cover, so it is also called the axle box rear cover. It is located in the interlayer of the back wall of the axle box, which is mostly wooden. The wood dust-proof board has poor sealing performance and often leaks shaft oil. In recent years, rubber dust-proof board is gradually used.
Rolling bearing axle box device
Advantages of rolling bearing axle box device
Compared with the plain bearing axle box device, the rolling bearing axle box device can reduce the running resistance of locomotive and vehicle by about 10% and the starting resistance by more than 80%. It can not only save the power consumption, improve the running speed, but also increase the traction weight of the train. The traveling clearance of each part of the device is small, which is conducive to improving the running quality of rolling stock. It has a small failure rate in operation, which can reduce the labor and material consumption of maintenance work. Therefore, although the manufacturing cost of rolling bearing axle box device is much higher than that of sliding bearing axle box device, it is still widely used.
Rolling bearing axle box device is usually composed of axle box, front and rear axle box cover, rolling bearing, sealing device and other parts. There are three kinds of rolling bearings used: cylinder, cone and sphere. The spherical rolling bearing bears better axial load, but it requires larger size, which is not conducive to reducing the weight under the spring, and has higher manufacturing cost and inconvenient maintenance, so it is seldom used in recent years.
Cylinder type rolling bearing axle box device is used in passenger cars in China Railway, and it is also mainly used in diesel locomotives and electric locomotives. In passenger cars, the axial force is borne by the flange on the inner and outer rings of the bearing, while in locomotives, the bearing generally does not have the flange, and the axial force is borne by the ball bearing installed on the end of the shaft. In addition to the cylindrical rolling bearing axle box device, the new freight car mainly uses the sealed tapered rolling bearing axle box device. The two ends of the tapered rolling bearing are provided with sealing devices, and the upper part of the outer ring is the bearing saddle, which is installed in the bogie side frame guide frame to play the role of load transmission. There is no longer a shaft box outside the bearing. Therefore, this structure is called "no axle box bearing device". All rolling bearings are made of grease, so it is not necessary to open the cover frequently for oil filling or inspection.
Maintenance of fag axle box device
In the use of bearings, FAG bearings and axle boxes need a long time of maintenance. Because this not only makes the bearing life longer, but also allows businesses to reduce costs.
The maintenance of fag bearing axle box is generally easier than that of sliding bearing axle box. It does not need to change bearing shells and add oil frequently, and there are fewer accidents of combustion shaft. But don't be careless