机车弛缓故障一直是困扰铁路安全部门的重要问题，而弛缓的原因是多方面的，既有人为的也有机械方面的原因，预防弛缓故障的关键技术是必须找到一种能有效检测弛缓故障的方法。本研究主要研究一种防止各类原因引起的弛缓故障。机车弛缓是指轮毂和轮箍之间发生的相对转动，由于机车车轮及刹车装置结构方面原因，机车弛缓故障的产生有多种原因。本文采用理论分析、实验室试验及现场试验运行相结合的方法研究了电力机车弛缓故障的产生、检测及评判算法，实现了机车防弛缓报警装置，主要工作有： （1）分析机车弛缓产生的原因，探讨机车弛缓时各个物理量的变化，寻找出一种有效的弛缓故障检测方式。 （2）设计了一种有效检测各类故障导致弛缓的传感器，该传感器一方面要能有效检测各类原因（人为和机械）引起的弛缓故障，另一方面要满足铁路部门安装要求。 （3）找到一种可靠的电力机车弛缓评判算法。这种故障算法受环境影响较少，不管在冬天还是在夏天都应有效。 （4）实现了机车防弛缓报警装置的研发，该装置可靠性高、安装方便、便于检修，有广阔的推广前景。

The mechanical failures caused by the wheel loose of locomotive are an important problem, which has been long puzzling the railway security units concerned. However, wheel loose consists in various reasons ranging from man-caused ones to mechanical ones. The key technology for preventing loose from happening is to find an effective method to detect the action of loose of the electric locomotive. The study focuses on working out a method to stop any type of mechanical failures from occurring. The action of loose of the electric locomotive refers to the relative turns between the hub and the hoop of a wheel. Owing to various reasons of the wheel and the mechanism of the brake system, the mechanical failures also consist in a variety of reasons. The paper discusses the causes of the mechanical failures by loose of the wheel first; then it offers detection and measuring calculation. The researchers concerned have devised an alarming device for preventing the action of loose from happing with the combination of the analysis of the theories with experiments conducted in labs, and with experimentation on the spot as well. The following are the major steps to make the system function successfully. （1） The reasons for loose are analyzed. The changes of physical quantities are then elaborated when loose happens. Moreover, a corresponding approach has been presented in the paper to detect mechanical failures caused by the loose of the locomotive. （2） A new sensor has been designed to effectively detect any action of loose. Meanwhile, the sensor is able to discover any type of failures caused by man or the wheel, and to meet the requirements for installment of the relevant railway security units. （3） A reliable measuring calculation for the loose of the electric locomotive has been found in the study. Such calculation is not easily affected by its surroundings and it works well either in summer or in winter. （4） The study of and development of the alarming device have been made. What’s more, the device is stable and installed and maintained with convenience. And this loose system of electric locomotive will have much greater potential to exploit in the future.