What Is The Train Brake Shoe?

Overview

Brake shoes are the brake parts that directly rub the wheels to stop the train when it is running. A shingle-shaped brake block made of cast iron or other material that holds the wheel tread tightly during braking and stops the wheel by friction. In this process, the braking device needs to convert the enormous kinetic energy into heat and dissipate into the atmosphere. The braking effect is good or bad, but mainly depends on the dissipation ability of friction heat energy. When using this braking method, the friction area of the brake shoe is small, and most of the heat load is borne by the wheel. The higher the train speed, the greater the heat load on the wheels when braking. If cast iron brake shoe is used, the temperature can melt the brake shoe; Even if the more advanced synthetic brake shoe is used, the temperature will be as high as 400~450 ° C. When the temperature of the wheel tread increases to a certain extent, it will make the tread wear, crack or peel, which will affect the service life and also affect the driving safety. It can be seen that the traditional tread brake shoe can not meet the needs of high-speed trains.

Parameter of Train Brake Shoes

Multi-dimensional parameter to build safety barrier performance evaluation has formed a standardized system of modern brake shoe, covering five core dimensions: friction stability (u value of 0.25 to 0.45) : in 40 ℃ to 800 ℃ – WenYu volatility should be less than 10%, avoid braking slide “hot” recession triggered risk. Wear matching: brake shoe and wheel wear than to control within the 1:8, both to ensure their durability, and reduce the wheels spin frequency. : by more than 100000 times the high frequency fatigue resistance braking test, surface crack growth rate should be less than 0.1 mm/ten thousand times. Environmental compliance: the eu REACH regulation requirements copper content lower than 5%, harmful material such as asbestos, lead, zero checked out. Energy dissipation efficiency: heavy-duty train brake shoe is required instantaneous 30 mj/kg energy absorption capacity, equivalent to 2 tons of heavy things falling from a height of 150 meter.

Intelligent Empowerment: From passive components to sensing terminals

From passive components to sense terminals with the penetration of the Internet of things technology, brake shoe are from pure mechanical parts for intelligent monitoring nodes: embedded sensor system: integrated real-time monitoring module, temperature, pressure, wear by LoRa wireless transmission to the vehicle control system. When the friction interface temperature exceeds 600 ° C, the cooling spray device can be automatically triggered. Self-healing coating technology: using microcapsules packaging technology, brake shoe surface scratch, nanometer silicon dioxide repair agent can be released automatically fill the defects, the friction coefficient of recovery rate of more than 95%. Digital twin prediction: based on the lifecycle data to establish the digital model of brake shoe, can 2000 kilometers ahead to predict residual life, guidance precision maintenance.

Different Application Scenarios

Adjust measures to local conditions of customized solution gave rise to different operating environment difference product matrix: cold high iron: adopting adding mos2 enhanced brake shoe at low temperature, the friction coefficient of deviation of 0.02 or less – 50 ℃ environment. Long and large ramp freight: tungsten copper composite brake shoe with forced air cooling system, continuous braking for 20 minutes temperature controllable within 400℃. Urban rail trains: nonmetallic brake shoe and magnetic track brake work together, achieve “sparkless brake”, perfect adaptation of the underground tunnel environment.

The Development of Train Brake Shoes

Harmony type high-power diesel locomotive is the main model of passenger and cargo transportation in China’s railway in the future, and gradually become the main traction power of China’s railway. With the increase of locomotive power, higher requirements are put forward for braking system. High friction coefficient composite brake shoe (hereinafter referred to as high friction composite brake shoe) is a key part of high power diesel locomotive braking, its quality and performance have an important impact on driving safety and maintenance cost. The harmony high-power diesel locomotive produced by Qishuyan Rolling Stock Plant of CSR Group through the introduction of GE technology has been widely used in China, but the high-friction synthetic brake shoe used is still the original product. Therefore, according to the requirements and characteristics of the harmonious high power diesel locomotive high friction composite brake shoe, this paper carries out the development of the harmonious high power diesel locomotive high friction composite brake shoe with independent intellectual property rights.