Basic composition and function of locomotive bogie

The basic composition and function of a locomotive bogie

The basic composition and function of a locomotive bogie. The bogie is an indispensable part of the locomotive. The AC bogie has the characteristics of high power and volume. Due to its many advantages such as small size and easy maintenance, it has become the first choice for mainstream locomotives. The following shares the basic composition and functions of the locomotive bogie. The basic composition and function of the locomotive bogie 1

The reason why EMU trains can run at high speed has a lot to do with the bogie of the EMU. Let’s first talk about what a bogie is. Usually, two or more wheel sets are assembled together with a special frame to form a car that can directly support the car body. This car is called a bogie.

So what is the function of the bogie of the EMU?

For EMUs or ordinary trains, the bogie is the most important part of the train. Whether the structure of the bogie is reasonable will directly affect the smoothness, stability and safety of the EMU train

For all high-speed trains, high-speed, stable and safe operation is inseparable from the steering rack technology. Moreover, our common subways and urban rails are inseparable from bogies, which shows how important bogies are to wheel-rail trains.

Functions of bogies

There are many functions of bogies, I will only briefly discuss them here. The first function is force transmission, which can also be called load-bearing, and plays the role of bearing the weight of the train;

The second function is buffering, also called shock absorption, which mainly ensures that the train has good stability. smoothness and stability. The third function is steering, which can also be called guidance, which guides the train to run on the rails;

The third function is braking. I believe everyone understands this function. On the contrary, The fifth function is driving.

Regarding the driving role of the bogie, I would like to emphasize one more point. Not all bogies have a driving function, only power bogies have a driving function, and non-power bogies have no driving function.

Basic components of the bogie

In order to achieve the above five functions, the bogie must have the following basic components. As I said before, the so-called basic components are all must-haves, and those that are optional cannot be considered basic components. Here I summarize the basic components of the bogie into five parts, taking the CRH380A EMU bogie as an example, as shown in the figure below.

Bogie composition

Looking up from the bottom of the bogie, the first one is called the wheel set, and the second one is called the axle box. The wheel set is installed inside the axle box. . The third one connects the axle box to the upper frame.

It is also called the primary suspension, which mainly includes axle box springs, axle box rotating arms, etc. The fourth part is the frame; the fifth part is the secondary springs, including air springs and various shock absorbing devices, whose main function is to connect the car body to the bogie below. The basic composition and function of locomotive bogies 2

In the composition of railway rolling stock, bogies are an important part. Generally speaking, the bogie has the following functions:

To bear the load, that is, to bear the load from the bogie, which mainly includes the car body and various machinery, electrical equipment and passengers installed inside the car body. The load is transferred to the rail through the elastic suspension device.

The traction force generated by the traction motor or the braking force generated by the braking device is transmitted to the car body chassis through traction devices such as traction rods, and then to the coupler part to achieve traction of the train. and braking. At the same time, centrifugal force and lateral force must be transmitted.

The function of buffering. During the operation of rolling stock, uneven lines will cause the impact of the line on the vehicle. After being buffered by the bogie suspension and other parts, the smooth operation of the vehicle is ensured. The guiding function uses the bogie to guide the rolling stock through curves and switches smoothly, ensuring the safety of the vehicle when running on curves.

The performance of the bogie structure directly determines the vehicle's traction capacity, running quality, wheel-rail wear and train operation safety. Therefore, the bogie should have the following technical requirements:

Ensure that the adhesion conditions are within Optimally, axle load transfer should be as small as possible.

The dynamic performance during operation is good to achieve small line action forces and reduce the stress and wear of the track and wheels.

It should meet the lightweight requirements and reduce its own weight as much as possible while meeting the strength and stiffness. The structure is simple, ensuring reliable operation, and the simple structure is conducive to reducing the maintenance workload. Bogie composition

As shown in the figure below (CRH2 EMU bogie), the bogie generally consists of the following parts:

CRH2 EMU bogie Assembling EMU bogie

Wheel set: directly transmits the weight of the vehicle to the rail, generates traction and braking force through wheel-rail adhesion, and realizes the guidance of the vehicle on the line through the rotation of the wheel set. Axle box: ensures the rotational movement of the wheelset, allowing the wheelset to adapt to the line conditions and move up and down, front and back, and left and right relative to the frame.

A series of elastic suspension devices: ensures even distribution of axle weight and mitigates the impact of uneven lines on the vehicle. It mainly includes axle box spring device, axle box positioning device and axle box vibration damping device. Frame: The skeleton part of the bogie, which is used to install the components of the bogie and bear and transmit vertical and horizontal forces.

Second-series suspension device: further alleviates impact vibration and allows the bogie to rotate relative to the vehicle body when passing through curves to ensure smooth operation of the vehicle. It mainly includes secondary spring devices, secondary damping devices, anti-roll devices, etc. Drive unit: transfers the power generated by the power unit to the wheelset.

Mainly includes traction motor, transmission device and motor suspension device. 7. Basic braking device: The force transmitted by the brake cylinder is increased by a certain magnification and then transferred to the executing mechanical mechanism to realize train braking. Basic composition and functions of locomotive bogies 3

There are many functions of bogies, so we will only briefly discuss them here. The first function is force transmission, which can also be called load-bearing, and plays the role of bearing the weight of the train; the second function is buffering, which is also called shock absorption, mainly to ensure that the train has good smoothness and stability.

The third function is steering, which can also be called guidance, which guides the train to run on the rails; the fourth function is braking. I believe everyone understands this function. On the contrary, The fifth function is driving.

1. Basic functions and requirements of bogies

Transportation: Bogies are used on vehicles to increase the load, length and volume of the vehicle, and to increase the running speed of the train to meet the development of railway transportation. needs; Movement form conversion: Ensure that under normal operating conditions, the car body can be reliably seated on the bogie, and the rolling of the wheels along the rail is converted into the translation of the car body running along the line through the bearing device;

Bearing: supports the car body, bears and transmits various loads and forces from the car body to the wheel pairs or from the wheel rails to the car body, and distributes the axle load evenly; Operation stability and safety: Ensure that the vehicle operates safely and can flexibly run along straight lines and pass curves smoothly;

1. Basic functions and requirements of bogies (continued)

Smooth Safety and safety: The structure of the bogie should facilitate the installation of the spring damping device so that it has good damping characteristics to ease the interaction between the vehicle and the line, reduce vibration and impact, reduce dynamic stress, and improve Vehicle operation stability and safety;

Traction and braking: Make full use of the adhesion between the wheels and rails to transmit traction and braking force, so that the vehicle has a good braking effect to ensure that the vehicle is within the specified distance. Parking within; Manufacturing and maintenance: The bogie is an independent component of the vehicle. It is required to minimize the number of connecting parts between the bogie and the vehicle body, and it is required to have a simple structure and easy assembly and disassembly, so that the bogie can be manufactured and inspected separately.