小型扭矩回差式两挡自动变速器

Light-Duty 2-Speed Automatic Transmission with Torque Backlash Shift Schedule

为了提高微型耕耘机等小型农业机械的自动化水平和操作舒适性,提出了一种根据作业阻力自动换挡的两挡自动变速器结构。换挡机构由摩擦离合器、超越离合器、端面凸轮和弹簧组成,无需电控和液压机构。采用扭矩式单参数回差换挡规律,降挡扭矩通过弹簧预压力进行调节,换挡回差主要由端面凸轮角度决定。换挡过程中动力不中断,离合器的接合压力保持恒定并传递稳定的扭矩,通过滑摩来逐渐达到转速同步,有利于降低换挡冲击。原理样机验证了变速器的自动换挡功能和换挡稳定性。

To improve the level of automation and operation comfort of light-duty agriculture ma-chines,such as micro-cultivator,a novel 2-speed automatic transmission structure was presented, which could shift according to tillage resistance automatically.The gearshift consisted of friction clutch,overrunning clutch,edge cam and springs,without hydraulic and electrical mechanism.Shift schedule was of single parameter backlash schedule of torque.Torque of down shift was adjusted by spring pre-load,and shift backlash was mainly decided by edge cam angle.During shifting process, torque was translated continuously and clutch pressure was constant to provide a steady torque.This characteristic is good for smoothing synchronization and reduces shifting shock.Prototype experiment was carried on,and the auto-shift function and stability was proved.