Axle is the main accessories of the wheel pair, it is in addition to the wheel composition of the wheel outside, the two ends of the axle box oil lubrication device with the axle box, to ensure the safe operation of the vehicle. According to its use of different bearings, axle is divided into sliding bearing axle and rolling bearing axle.
1. Centre hole: processing axle and assembly, processing wheel pairs when the machine tool ejector hole pivot point, and can be used as a proofreading journals, wheel roundness of the centre.
2. Shaft end bolt hole: installation of bearing front cover or pressure plate, to prevent the rolling bearing outward movement out, as shown in Figure 2-2 (b).
3. Shaft journal: to place the bearing, bear vertical load.
4. unloading groove: for grinding journals to facilitate the grinding wheel back knife, the role of the back knife groove, you can reduce the assembly of the inner ring of the bearing and the contact stresses between each other here, is conducive to improving the fatigue strength here
5. Journal shoulder: journal and dust retaining ring seat between the transition arc, can prevent stress concentration.
6. Dust retaining ring seat: installation of dust retaining ring and limit the rolling bearing backward movement.
7. Wheel seat front shoulder: dust retaining ring seat and the transition arc between the wheel seat, can prevent stress concentration.
8. Wheel base: fixed wheel, is the largest part of the axle force.
9. Wheel base rear shoulder: the transition arc between the wheel base and the axle body, which can prevent stress concentration.
10. Axle body: the middle part of the axle connection.
11. Axle end chamfer: the end of the axle is equipped with a 1:10 chamfer, its role is to play a guiding role in the press-fit rolling bearings.
Sliding bearing axle and rolling bearing axle ministries name and function are basically the same, the difference is as follows:
1. Increase the collar: mainly to prevent outward movement of the axle tile.
2. Shaft journal: the installation of sliding bearings of the axle tile.
3. There is no bolt hole at the end of the shaft.
4. No unloading groove.
Train axle is a key component connecting train wheels and body, which is subject to huge loads and impacts. In order to ensure the strength and stability of the axle, its machining process needs to go through a number of procedures.
1. Raw material preparation: according to the design requirements, select the appropriate material for the production of axles. Commonly used materials include carbon steel, alloy steel and so on.
2. Heat treatment: axles need to have a certain degree of strength and toughness in the process of use, in order to meet these requirements, the need for heat treatment. Commonly used heat treatment methods include tempering, normalising and so on.
3. Primary processing: the heat-treated axle forging and rolling, so that its initial shape. In this process, you need to master the control of temperature and pressure to ensure the physical properties of the axle.
4. Finishing: the initial processing of the axle for turning, milling and other machining processes, so that it forms the final shape and size. In this process, it is necessary to ensure the roundness, parallelism and other precision requirements of the axle.
5. Quenching and tempering: After finishing, the axle needs to be quenched and tempered to improve its mechanical properties and wear resistance. Quenching makes the surface of the axle form a layer of high hardness, wear resistance and good organisation, while tempering makes the overall toughness.
6. Detection: non-destructive and destructive testing of the processed axle. Non-destructive testing, including ultrasonic testing, magnetic particle testing, etc., can find the inherent defects of the axle; destructive testing of the axle material through the tensile, impact and other tests to understand its strength and toughness.
7. Surface treatment: the axle is polished, sprayed and other surface treatment to improve its appearance and corrosion resistance. Spraying can use coating technology to increase the wear resistance and lubrication of the axle.
8. Assembly: The surface treated axle is assembled with other parts such as wheels and body to form a complete train vehicle.
