Design principles in the development of the spring industry

A spring is a mechanical part that uses elasticity to work. Generally made of spring steel. Used to control the movement of machine parts, reduce shock or vibration, store energy, measuring the size of force, etc. , widely used in machines, instruments. According to the shape of the score, mainly coil spring, disc spring, vortex spring, plate spring and so on.

Railway vehicles can be divided into car body, bogie, connection buffer and other parts. The bogie is the walking part of the railway vehicle, its role is to bear the weight of the upper part of the vehicle body, transmit traction and braking power, and mitigate the impact of the line on the vehicle. The bogie generally includes the wheel-to-axle box device, the elastic suspension device, the frame and side frame, the basic brake device, the body support device and other parts. At present, the main frame of China’s railway truck is the turn 8A type bogie, including: bearings, wheel pairs, side frames, rollers, rockers, pillows, chute-type basic brake devices, side bearings and lower core plate and other major components.

The design of the bogie is a complicated problem in the design of railway truck, and the safety and smoothness of vehicle operation mainly dependonon on whether the design of the bogie is reasonable. The spring shock absorber in the bogie design is the key component, the main parameters of the spring damper are more than 20, the static constraints have more than a dozen, the vibration of the vehicle system (including vertical, horizontal, rolling, nodding and so on), the snake movement of the wheel-to-wheel (different at low speed, high speed), the curve of the train through the characteristics (anti-overtion through the bend, anti-deorbiting performance) and other dynamic properties are directly related to the structural parameters of the spring shock absorber.

The design of the bogie generally has to go through the design parameters, finite element analysis and dynamic performance verification three steps, the current design activities follow the form of “design, analysis, change”, that is, the limited element analysis or dynamic performance verification findings can not meet the requirements, and then return to the design department to modify. Because of the more parameters involved and the coupling relationship between parameters is more complicated, the design of the bogie structure parameters often takes more time. In particular, the effect of structural parameters on the dynamic performance of vehicles, often can only rely on the experience of designers to judge, when the model is more complex, easy to cause the designer’s judgment error, engineering changes bring product development cycle extension, quality level decline and so on.

Therefore, it is necessary to provide designers with a tool to intuitively understand the effect of parameter adjustment on dynamic performance when carrying out the design calculation of structural parameters. Here is a simple example of how to use the design principle system guidance parameters adjustment.

The spring damper in the bogie is treated as a key component, simulating its behavior and interpreting its principles, but the designer analyzes the vibration performance of the vehicle after completing the parameter design of the spring and the damper. In the simplified model of the vehicle vibration system, (a) only the vertical free vibration with nonlinear damping is considered, (b) is the schematic of the spring damper, the parameters of the spring damper are more than 20, including the reed diameter, spring lap number, spring stiffness, friction angle, friction almantry coefficient, etc., according to the simulation needs to be properly simplified.