The train wheelset is a key component of the train, consisting of an axle and two wheels. This article will introduce in detail the characteristics of the axle and different types of train wheels.
Wheelset
The train wheel set is composed of an axle and two wheels pressed together. During the operation of the vehicle, no relative displacement is allowed between the wheels and axles. The wheelset bears the entire weight of the vehicle, and also bears various other forces from the car body and the rails when running at high speed on the track.
The axles on the wheel set can be divided into sliding bearing axles and rolling bearing axles according to the type of bearing used. The structures, shapes, sizes, and materials of wheels are diverse. According to their use, they can be divided into passenger car, truck and locomotive wheels. According to their structure, they can be divided into integral wheels and tire wheels. Integral wheels can be divided into rolled steel wheels, cast steel wheels, etc. according to their materials.
In addition, in order to reduce noise and unsprung mass, new wheels such as elastic wheels, silencer wheels, and wrinkled spoke wheels are also used abroad. Regardless of any form of wheel, the parts that are in direct contact with the rail are mainly the rim and tread. The rim is the protruding part on the inside of the wheel. Its function is to guide the running direction of the wheel and prevent the wheel from derailing. The tread is the contact surface between the wheel and the rail head.
Axle
A shaft is a cylindrical object that goes through the middle of a bearing or a wheel or a gear. It is a mechanical part that supports rotating parts and rotates with them to transmit motion, torque or bending moment. It is generally in the shape of a metal round rod, and each segment can have a different diameter. The parts that perform rotary motion in the machine are mounted on the shaft. According to the different uses of the shaft, the materials of the shaft also vary.
The materials of the shaft are mainly carbon steel and alloy steel. Among them, high-quality carbon structural steels such as carbon steel 35, 45, and 50 are widely used because of their high comprehensive mechanical properties. Among them, 45 steel is the most widely used. In order to improve its mechanical properties, it should be normalized or quenched and tempered. For shafts that are not important or have small stress, carbon structural steel such as Q235 and Q275 can be used. Alloy steel has higher mechanical properties, but is more expensive and is mostly used for shafts with special requirements. For example, high-speed shafts using sliding bearings often use low-carbon alloy structural steels such as 20Cr and 20CrMnTi. After carburizing and quenching, the wear resistance of the journal can be improved; the machine rotor shaft must have good wear resistance when working under high temperature, high speed and heavy load conditions. For high temperature mechanical properties, alloy structural steels such as 40CrNi and 38CrMoAlA are often used.
In addition, for the shaft blanks, forgings are given priority, followed by steel; for larger sizes or complex structures, cast steel or ductile iron can be considered. For example, using ductile iron to manufacture crankshafts and camshafts has the advantages of low cost, good vibration absorption, low sensitivity to stress concentration, and good strength.
Integral rolling steel rail wheel
The integral rolling steel wheel is referred to as the rolling steel wheel. It is a wheel made of steel keys or wheel blanks that are heated and rolled and then heat-treated with match fire. It has the advantages of high strength, good toughness, light weight, safety and reliability. It will not cause loosening or cracking of the wheel hoop during use, adapts to the requirements of heavy load and high running speed, and has low maintenance costs. If the rim wear is excessive, it can be surfacing welded; if the tread is worn, it can be turned and used for correction.
However, the manufacturing technology of steel rolling wheels is more complex, the equipment investment is large, and the wear resistance of the tread is not as good as that of wheel hoops.
Integral cast steel rail wheel
The integral cast steel wheel is a type of wheel that uses a casting process to produce wheel blanks, and then undergoes surface treatment and machining to obtain the finished product. It is characterized by high strength, plasticity and toughness, and relatively low production cost. It is suitable for parts that bear large loads in heavy machinery, such as ball mill bearing bases. This kind of wheel has high hardness and strong wear resistance, and can fully support the operation of the mill bearings.
In the production process, although the process steps of integrally cast steel wheels are relatively few, the requirements are very high. Its production process includes raw materials, blast furnace smelting, molten steel discharging, graphite casting, casting cleaning, heat treatment, surface treatment, machining, quality inspection and finished product delivery.
LM type rim tread wheel
The LM type rim tread wheel is a wheel with a specific geometry and size, which is characterized by a larger contact area and lower wheel-rail contact stress, thereby improving the wear performance and traction performance of the wheel and rail. In addition, LM-type rim tread wheels also have good anti-rolling performance and curve passing performance, which can make the vehicle run more smoothly and improve passenger comfort.
LM type rim tread wheels are mainly used on railway vehicles. Their use can reduce the number of vehicle maintenance and wheel replacements and reduce operating costs. In addition, LM-type rim tread wheels can also improve the operational safety and stability of vehicles and reduce the occurrence of vehicle breakdowns and accidents.
