Structural Design And Optimization Of Car Electric Door Lock

As a key component of the entire car door system,the performance of car door locks has a significant impact on passenger safety and the security of property inside the vehicle.Nowadays,car door lock systems have various functions,but are complicated to assemble.To reduce the difficulty of door lock assembly,this paper designs a electric door lock that integrates electric unlocking/locking function,electric safety unlocking/locking function,electric child safety lock unlocking/locking function,Inner/external opening handle unlocking function,manual safety unlocking/locking function,manual child safety lock unlocking/locking function and emergency unlocking function for reducing the use of intermediate accessories.Due to the significant influence of car weight on fuel consumption and driving range,research on car lightweighting has become increasingly important.Car door locks,as part of the car’s weight,face higher requirements for lightweighting while maintaining performance.In this paper,we read a large amount of literature about car door lock components and working principles,and optimize the design of car door lock from six aspects,including design modeling,force analysis,finite element analysis,topology optimization,fatigue analysis,and performance verification.Firstly,the basic functions,performance requirements,and design requirements of car door lock systems were introduced.The working principle of the electric door lock’s various branch chains was expressed through a motion diagram,and the approximate composition of each branch chain was introduced.Then,the latch,the lock housing and each branch chain structure were designed separately,and assembled using Solidworks.The electric door lock was designed to reduce the mass by 0.23 kg compared to the sum of the quality of the door lock and intermediate accessories of a certain door lock system.Secondly,the force diagram of important components in the door lock electric branch chain was drawn,and a finite element model was established.Topology optimization was performed on the components with the objective function of minimizing weight and the constraint condition of maximum stress not exceeding allowable stress.Single or multi-model topology optimization methods were applied according to the number of working conditions of the components to achieve optimization.After topology optimization,the dimensions of the components were further optimized to minimize their weight.Fatigue analysis was conducted on the components during the optimization process to ensure that the optimized components met the design requirements.The optimized gear plate’s weight was reduced from 31 g to 21.2 g,a weight reduction of about 32%;the stucking plate’s weight was reduced from 81.8 g to 41.3 g,a weight reduction of about50%;and the lock stop plate’s weight was reduced from 40.2 g to 22.2 g,a weight reduction of about 45%,total door lock weight reduced by 68.5 g.Compared with the sum of the quality of the door lock and intermediate accessories of a certain door lock system,the optimized door lock has reduced by 298.5 g in quality,with a weight reduction ratio of19.6%,achieving a lightweight car door lock.Finally,according to the requirements of the national standard GB 15086-2013,the lock body structure of the optimized door lock was subjected to load tests under load test 1and load test 2 using a tension machine.The test results showed that the latch met the strength requirements.The door lock’s inertial force was calculated,and the results showed that the door lock met the withstand inertia requirements.The durability test was conducted on the door lock using the durability test bench,and the test results showed that the optimized door lock could meet the durability requirements in the industry standard QC/T 627-2013.