In the early days of railway freight cars in China, sliding bearing axle box devices were mainly composed of axle box bodies, axle box covers, bearing shells, bearing pad plates, lubrication devices, and dust-proof plates. They were generally installed on the outside of the wheels and have now been replaced by rolling bearing devices without axle boxes. Their function is to transfer the weight and load of the car to the wheelsets, lubricate the axle necks, reduce friction, and lower operating resistance.
◆ Axle box body
The axle box body is a component that bears loads and stores axle oil, used to accommodate the shaft neck and other parts. The axle box body and the axle box cover must be tightly fitted to prevent oil leakage and prevent rainwater and dust from entering. The axle box body can be divided into two types: guide frame type and non guide frame type.
The axle box body not only transfers the load from the steering frame to the journal, but also bears the load supported by the jack from the bottom when repairing and replacing bearings, so it needs to have sufficient strength. Early axle boxes were generally made of cast iron, while later they were commonly made of cast steel.
◆ Bearing shell
The bearing shell is a component that rubs against the journal and transfers all the load borne by the axle box body to the journal. It is composed of the bearing shell and a layer of anti friction alloy on its surface. Early tile bodies were cast with copper alloys, and later steel backed copper liners were used. In China, ductile iron was used for manufacturing; The anti friction bearing alloy used, commonly known as white alloy, is lead antimony tin alloy. This alloy is easy to scrape and has good compressive, anti friction, and heat resistance properties, and is easy to cast.
In order to prevent premature scrapping of the bearing shells and avoid shaft burning, plastic bearing heads are installed at the front end of the bearing shells of railway freight cars with a load capacity of over 50 tons.
◆ Bearing pad
The bearing pad is a component installed between the axle box body and the bearing pad for load transmission. Its upper surface is arc-shaped to improve the load distribution on the white alloy surface. When replacing the bearing pad, removing the pad first can reduce the lifting height of the jack.
◆Oil lubrication device
Oil lubrication device is a device that supplies shaft oil between the bearing shell and the journal to reduce friction. It is mainly composed of oil coils, wooden front pillows, and rear baffles, installed inside the axle box.
The oil roll is filled with shaft oil (lubricating oil) and comes into contact with the lower part of the shaft neck. When the vehicle is running, the shaft neck rotates, bringing the shaft oil into the space between the bearing shell and the shaft neck, forming an oil film and turning dry friction into liquid friction. In the early days, oil rolls were mostly made of cotton wool, and some were made of oil brushes. In China, railway wagons used oil rolls wrapped in foam plastic with towel covers.
The function of the wooden front pillow is to replace the oil coil at the outer end of the shaft neck and prevent the oil coil from moving outward.
The rear baffle is used to prevent shaft oil from overflowing from the rear end of the shaft neck.
◆ Dustproof board
The function of the dust-proof plate is the same as that of the axle box cover, so it is also called the axle box back cover. It is located in the interlayer of the rear wall of the axle box body. In the early days, it was mostly made of wood, and the wooden dust-proof plate had poor sealing and often leaked axle oil. Later, rubber dust-proof plates were gradually used.
1-Axle box cover; 2. One bearing pad; Three axle box body; 4. Bearing shells; 5. Dust proof board; 6. Oil lubrication device
2024 September 1st Week Marginal Product Recommendation:
Material Specification Sheet–MG-6:
Material specification sheet – MG-6 is Ball and roller bearing steel according to EN ISO 683-17. Ball and roller bearing steel for balls and rollers of any dimension,rings and discs up to 30mm effective thickness.
