An actuating mechanism of a parking braking system comprises a support, a gear shifting shaft, a tooth-shaped plate, an actuator spring, a guide plate, a row fixing pin, a push rod, a guide rod, a pawl and a pawl reset spring. The gear shifting shaft is arranged on the support in a penetrating mode; the tooth-shaped plate, the actuator spring and the guide plate are installed on the gear shiftingshaft; the tooth-shaped plate and the gear shifting shaft rotate synchronously and are matched with the row fixing pin; the actuator spring is connected with the tooth-shaped plate and the guide plate; the upper end of the push rod is rotatably connected to the support, the lower end is provided with a roller, and the middle part is provided with a support arm, and a guide rod is connected betweenthe support arm and the guide plate; the rear end of the pawl is rotatably connected to the support, the front end of the lower edge is provided with a ratchet, and the upper edge is provided with aflange; one end of the pawl reset spring is connected with the pawl; a limiting protrusion is arranged on the support, located on the rear side of the guide plate and matched with the guide plate. Byadopting the dead point principle of the three-connecting-rod mechanism, self-locking of the actuating mechanism at the P gear is achieved, the peripheral support face can be completed only through one limit, the structure is simple, parts are reduced, and the space is reduced.

一种驻车制动系统的执行机构，包括支座、换挡轴、齿形板、执行器弹簧、导板、定排销、推杆、导杆、棘爪、棘爪复位弹簧；换挡轴穿设于支座上，换挡轴上安装有齿形板、执行器弹簧、导板，齿形板与换挡轴同步转动且与定排销配合，执行器弹簧连接齿形板和导板；推杆的上端转动连接于支座上，下端设有滚轮，中部设有支臂，支臂和导板之间连接有导杆；棘爪的后端转动连接于支座上，下沿的前端设有棘齿，上沿设有凸棱；棘爪复位弹簧的一端与棘爪连接；其中，支座上设有限位凸起，限位凸起位于导板的后侧且与导板相配合。本发明采用三连杆机构的死点原理实现执行机构在P挡自锁，外围支撑面仅需一个限位就能完成，结构简单，减少了零件，减小了空间。