Considering closing spring failure of operating mechanisms in high voltage circuit breaker

reliability design theory was applied to analyze it

and found reason of spring failure because of lacking fatigue reliability

and offered some measures to solve the problem.In convention design theory

spring parameters such as outer load

geometry

and material strength properties are regarded as certainty.In fact

affected by material

manufacture

and measurement

they are uncertain so as to cause spring failure because of lacking reliability usually.In reliability design theory

these parameters were taken as random variables and used probability statistics method to study spring intensity.It offered a quantitative answer to the probability problem of spring failure

and people can assure the quality of spring.Solution of the problems includes improvement of spring geometric size

material

manufacturing technology

and bearing condition

but for the old equipment

some actual conditions such as economization

technology

feasibility should be considered.By comparison

shot-peening to deal with spring surface was chosen as the best way finally.Improvement result showed spring fatigue reliability was sufficient.