Wheel pairs of wagons. Malfunctions of wheel pairs of railway wagons

The undercarriage of railway trains includes many elements in its design, but the key one is the wheel pair. There are different versions of this component, and they differ not only in size and shape, but also ability to withstand different loads. In many respects this characteristic is the determining factor for the working resource of the running gear. Manufacturers initially endow its elements with high operational potential, but, of course, this does not guarantee the complete elimination of breakages and malfunctions. Regardless of the purpose and characteristics of the use of transport, wheel pairs of wagons require maintenance of a healthy condition. By the way, elementary wear is a normal phenomenon - it's another matter that maintenance personnel need timely detection of sites close to breakage and the performance of appropriate repair operations.

Causes of malfunctions

Despite the use of a reliable design with high-strength metal alloys, strong dynamic and static loads can lead not only to wear, but also to deformation. To the greatest degree such phenomena are affected by wheel pairs of freight cars, as during the movement of the train there is an increased voltage in the contact zone of the rails and wheels. Therefore, in order to minimize the negative consequences of this interaction, technologists include carbon in the alloy in large proportions. Either way, loads can increase if the crew follows the terrain with a crooked roadway - this creates additional stress due to centrifugal forces.

In this case, do not think that couples for passenger trains have serious advantages in the form of low loads. In part, of course, the risks in this case are lower, but all impacts and jolts in the process of movement are also transmitted to the running gear, resulting in the wheel pair of the passenger car gradually deteriorating. It is worth noting and other factors affecting the condition of the wheels. Among them, braking forces, the effect of skidding, undesirable contacts of the axis with the drive part, arrows, etc. Now it is possible to become more familiar with the most common types of malfunctions.

Wear of solid wheels

There are several groups of similar wear. First of all, this is the formation of a uniform rolling, to which wheelset wheels are subjected even in the normal operation mode. The appearance of such a deformation is due to the fact that when contacting the rails and brake pads, a strong stress is created, which entails rolling on the surface of the wheels.

An uneven rolling is also common. It is characterized by the appearance of deformation zones not over the entire area of the contact zone, but only in certain axes. This indicates that wheel sets of cars were manufactured with an uneven distribution of properties over the entire mass of the alloy. That is, the appearance of such a rolling testifies, first of all, to marriage in the pairs themselves. Further, it is worth noting the circular influx. It can be observed outside the contact rim of the wheel, when the mass drifts along the sides of the chamfer.

Wear of rolling surfaces

Deformation of this kind also occurs on the area of the contact zone. A feature of wear and tear is that it occurs when moving by a yuz. Therefore, the deformation of rolling surfaces is often associated with disruptions in the work of brake pads. Visually, such wheel pair faults appear as a slider - a flat area on a white metal surface. Despite the fact that in the process of exploitation such defects do not cause serious problems, they can go into trouble of another kind.

The fact is that in places of the slider almost always there is an increased formation of heat, which is transmitted deep into the rim of the wheel. As a result, so-called scrapes are formed, attracting a specific coloration at the point of rolling. Over time, the wheel pair begins to respond sensitively to any unevenness of the "canvas", which results in the appearance of impacts in the running gear. Therefore, if the sliders are detected more than 1 mm, then the speed of the train is imposed serious limitations. By the way, the wheel pair of a diesel locomotive and a freight car are most susceptible to such deformation. It is noteworthy that the intensity of the formation of the slider depends on the season - for example, in winter and early spring the risks of its formation are higher.

Axis faults

Malfunctions in necks and pre-precessional parts are expressed in the form of small-dimensionality of axes. There may be several reasons for this. First of all, the deformation occurs due to insufficiently strong connection and in cases where the metal surfaces were cleaned from the rust formations incorrectly. Also, the axis of the wheel pair is often fractured and cracked in places with the highest loads. Similar processes occur due to cyclic stress, the presence of sections with transition cross sections and the discontinuity of the metal itself. Of course, the usual breakdowns in the form of insufficiently strong fastenings of bolts and nuts are not excluded.

Navar Metal

This damage thermomechanical nature, which affects wheel pairs of cars in the surfaces of skiing. During inspections such deformations fix the zones of shear of material with U-shaped form. In essence, this is a kind of plastic deformation processes. The maximum shift occurs on the central part of the contact strip. In turn, the minimum shift can be detected at the edges. The cause of such damage is the distribution of loads with pressure on the contact area.

General measures for maintenance of wheels

Preventive measures contribute to the extension of the use of the wheels. Maintenance involves examinations, surveys, indications for repair operations, etc. If we talk about technical measures, the main one will be the correct turning of wheel sets with a minimum layer of metal removal. The number of turning points is reduced due to special measures aimed at increasing the reliability of wheel sets and eliminating the existing weak points of the running gear. In particular, specialists strive to eliminate the force factors that occur in the process of exploitation and appear due to previously arisen defects. For example, problems in the springs and springs, which affect the performance of the running gear, are eliminated.

Repair and recovery operations

Repair operations are carried out in a special mechanical zone after the elements have been thoroughly washed. In a special department, the wheels are changed, turning or holding welding events. If it is planned to repair wheel sets in order to change the profile of the elements, the work is done using special templates. It should be noted that the permissible deviation in the parameters of the wheels from the template is 1 mm at the ridge height, and along the inner faces and the skiing area - 0.5 mm. As already mentioned, electric welding operations can be used for repair. Such equipment is used to cut the axial thread and surfacing the center holes.

Conclusion

There are special regulations, which detail the faulty wheel sets, as well as methods and technologies for their elimination and prevention. It is important to note that the chassis has a number of mechanical properties in general. As a result, the working capacity and the resource of the wheel pair depend not only on the quality of the tracks, but also on the braking system, the spring-spring unit, the mode of the crew's movement and even the time of the year.