Combined Crank‐Slider and Rack‐Gear Structures for Energy Harvesting and Impact Reduction of the Car Door

Harvesting energy from the door closing process provides a promising solution for powering wireless sensors in intelligent transport systems, however issues, such as low conversion efficiency and operational resistance hinder its practical application. In this study, an energy harvesting system (EHS) is proposed and its basic and optimized designs are compared and analyzed. The system integrates a crank‐slider mechanism, a rack‐and‐pinion transmission and a flywheel energy storage module: the crank‐slider converts the rotational motion of the door into linear motion, the rack‐and‐pinion gears are engaged only at preset positions to minimize operating resistance, and the flywheel captures the kinetic energy quickly during the door closing process. The key parameters (crank length: 19.8–25.8 cm; connecting rod length: 25–31 cm; engagement angle: 26°–44°; flywheel inertia: 0–102.6 kg‐mm 2 ) were optimized through orthogonal experiments. The results show that the flexible design improves the energy output by 13% compared with the rigid design (35.96–73.79 mJ/time for 1–6 J input), and the orthogonal analysis shows that the eigenvalues of the parameters are distributed in a balanced way, which verifies the feasibility of eliminating the impact kinetic energy loss through elastic contact. In addition, the flexible design reduces the door closing noise by 3–12 dB. Experimental validation shows that the system is capable of providing minute‐level continuous power supply for low‐power sensors.