Car Shock Absorbers Work Of Occupational Fatigue Analysis Study

Modern automobile industry has the trait of automation, assembly work and high degree mechanization. But in the inner line of final shop, on the lift shock absorber installment location, operators have to lift shock absorber weighted 10kg delicately, meanwhile keep the posture of forwarding squatting for work. So it has a serious degree on the physical task load. It will cause illness of Work-related Musculoskeletal Disorders (WMSD) exposing against of this safety ergonomics conditions for a long time. Therefore, to study the operator's physical task load and the problems concerning WMSD of this working site is very valuable significance.Based on the background above mentioned, this research select lift shock absorber installment working site as study point, use movement safe analysis method, computational method concerning relevant biological mechanics analysis as well as Jack ergonomics software simulation means to find suspicious movements caused the WMSD in this working site, to judge whether exist risks caused operators become this kind of work-related disorders, and to analyze the reasons about falling this illness, meanwhile, put the proposes and thinking on how to reduce the disease incidence rate of WMSD as well as safety accidents.The main conclusions and gains as follows:(1) The numerical value of single stress instantaneous hasn't pass the standard about NOISH 3400N ultimate limit load value required. This means the stress is not the primary reason caused WMSD on this working location.(2) In the same work posture or in the high duplication frequency without enough restorable time is the main reason lead to bring about WMSD on this location.(3) In the 32 decomposition movements of one movement cycle, the tighten work loosen installment work on back shock absorber have the high WMSD disease incidence rate because their theory restorable time (360s needed the same) less than the practical restorable time (respectively needed 88s and 37s).(4) This research has designed two improvement postures. In order to reduce the shear stress and stretch stress of the vertebra by changing squats posture to the kneeling position or changing the line track gradient. Wish using these means to reduce the risk on falling WMSD. It has a practical significance to reduce occupational disease and the prevention on occupational safety accident.