| Intelligent connected vehicles have become another industry hot spot after new energy vehicle,and their smart door latch are a key part of the vehicle intelligent entry systems.As a device for vehicles door latchs,the internal mechanism of the door latch mainly uses pair and higher pair contact structure to construct a cam link mechanism to transmit contact force.Upgrading traditional door latchs to intelligent door latchs with new functions of electric opening and electric suction is an urgent problem to be solved,and it is a key to enhance the competitiveness of domestic door latchs in the future intelligent connected car market.The core task of vehicle door latch mechanism design is to carry out innovative design of electric release kinematic chains in the narrow space.This paper analyzes and studies the release mechanism,insurance mechanism and locking mechanism of a door latch,and uses an ordered single-open chain method to add an electric release branch chain to the door latch.A new electric insurance branch chain was designed to adapt to the electric release of the single drive double branch chain,and a new locking mechanism was proposed to cope with the closing force under the large sealing reaction force.The specific research content mainly includes the following aspects:(1)Based on the topological theory of planar mechanism,facing the existing side door latch with internal and external release function,a new type of electric release kinematic chain is designed on the basis of the original kinematic chain.The structure is synthesized by using the two-color topology diagram of a single open chain,and an open branch chain topology diagram of an eight-pole three-loop single degree of freedom is obtained.Taking the kinematic compatibility of each kinematic branch chain in the door latch as a constraint,a type of structure that satisfies the functional requirements is selected to realize the kinematic chain design of the electric release function.(2)Aiming at the logic and speed coordination problems of single-motor controlledelectronic insurance branch and electric door release branch,a new type of double-layer insurance fork mechanism with locking and adaptive characteristics was proposed by analyzing the motion characteristics of general insurance branch chains.By analyzing the motion mode of the double-layer safety shift fork and performing kinematics analysis on the electric release branch chain,the speed and acceleration of the toggle pawl when the electric opening is obtained are obtained.(3)Aiming at the large closing reaction force of the vehicle door,the locking mechanism of the door latch is subject to greater impact and wear.A new ratchet pawl locking mechanism with main and auxiliary pawls is proposed,and the auxiliary pawl is composed of a spring link mechanism.The new locking mechanism uses the flexible impact of the auxiliary pawl and the rigid impact of the main pawl to replace a rigid impact of the conventional locking mechanism.The effects of spring stiffness of different auxiliary pawls on the hysteresis and contact force of the main pawl were discussed through dynamic simulation.(4)The dynamics of the electric suction and electric release process of the door is analyzed,and the movement trajectory of the door latch during the door opening and closing process is analyzed.According to the motion trajectory of the door lock,the resistance to be overcome during the electric suction process is analyzed,and the related energy consumption model of the seal,the door weight energy consumption model,and the energy consumption model of the locking mechanism are established.The Lagrange equation is used to model the dynamics of the transmission mechanism when the door latch is electrically released.The dynamic simulation of the electric release in the single-drive double-branch chain mode was performed,and the influencing factors of the double-layer insurance fork mechanism of the electric insurance branch chain were explored. |
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