Abstract: The gear switch is one of the import electrical components on the transmission, and its output signal indicates whether the transmission is hanging into the corresponding gear, which avoids a protective device that makes the vehicle rush forward when the gear is already in gear. The working reliability of the gear switch directly affects the driver's driving experience. Aiming at the problem that the gear switch used in heavy truck, by improving the temperature resistance grade of the engineering plastic parts inside the switch, optimizing the high and low temperature performance of the rubber parts and adjusting the internal strucure of the switch, make the gear switch meet the use requirements of the gearbox under complex environmental conditions.

Key words: High and low temperature environment; Gear switch; High and low temperature performance; Temperature resistance grade of the engineering plastic parts; High and low temperature performance of the rubber parts

摘要： 挡位开关是变速器上重要的电器元件之一，其输出信号指示变速箱是否挂入相应挡位， 避免在挡启动发动机使车辆前冲的一种安全保护装置，挡位开关的工作可靠性直接影响驾驶 员的驾驶体验，文章针对重卡变速箱用挡位开关在高低温环境下工作不可靠的问题，通过提 升开关内部工程塑料件耐高温等级、优化橡胶件高低温性能和调整开关内部结构，使挡位开 关满足变速箱复杂环境工况下的使用要求。

关键词: 高低温环境；挡位开关；高低温性能；工程塑料件耐高温等级；橡胶件高低温性能