Design Study Of Eccentric Adjuster For Automotive Seat With Less Gear Difference

With the increasing requirements for automotive safety,seat safety is of great concern.As a key component of the seat,the reliability of the angle adjuster directly affects the safety performance of the seat.This paper proposes a new type of eccentric angle adjuster with less gear difference to improve the traditional angle adjuster transmission locking structure and improve the transmission smoothness and locking performance,the main research content is as follows.(1)This paper describes the structure composition and working principle of traditional angle adjuster,and analyzes the motion state of transmission and locking structure in detail.From which the theoretical curves of speed,acceleration and displacement of conventional angle adjuster under 20 N·m torque are derived.These findings provide theoretical support for the subsequent dynamics comparison simulation for selecting moments,setting simulation targets and results comparison verification.(2)This paper proposes a new type of differential less eccentric angle adjuster and analyzes its working principle and structural features.This scheme selects the planetary transmission structure with less differential gearing and adopts double eccentric brake shoe drive,which ensures excellent locking effect while offsetting the inertia force generated by the less differential gearing mechanism and mitigates the adverse effects such as vibration and noise.(3)The finite element analysis of the conventional angle adjuster and the less differential eccentric angle adjuster is carried out,mainly including: the strength analysis of the two types of angle adjusters under the locking condition,the maximum equivalent force reduction of the less differential eccentric angle adjuster is 34.9% and20.3% respectively when the load of 1200 N·m and 2000 N·m is applied,which indicates that the structural strength of the less differential eccentric angle adjuster has been significantly improved;The maximum friction force of the less differential eccentric angle adjuster in both angular and locking conditions appears on the contact surface of the bushing,and the friction force in locking condition is about 20 times of the angular condition,which indicates that the locking effect of the less differential eccentric angle adjuster is obvious;the modal analysis of the less differential eccentric angle adjuster shows that the inherent frequency of the system;The modal analysis of the eccentric angle adjuster with less gearing shows that the inherent frequency of the system is much higher than the excitation frequency that the car generally bears,which indicates that there is no resonance phenomenon.It verifies the structural design rationality and superior locking performance of the eccentric angle adjuster with less gear difference.(4)The dynamics simulation of the traditional angle adjuster and less differential eccentric angle adjuster,compare and analyze the speed,displacement,acceleration and force change curve between the two parts,found that less differential eccentric angle adjuster angular speed change amplitude is only 31.8% of the traditional angle adjuster,angular speed and force change amplitude is only about 10% of the traditional angle adjuster,has a stable speed characteristics,acceleration is almost zero,the force between the parts Continuous and stable,with stable and good dynamic performance and comfort.