Stress relief method for a fluid filled elastomeric bladder

摘要

An improved method of producing a fluid filled elastomeric bladder for occupant weight sensing involves annealing the bladder material prior to its installation in a vehicle seat so as to quickly relieve initial stress due to stretching of the bladder material which occurs during fluid injection. In a preferred implementation, the initial stress is relieved by immersing the fluid-filled bladders in heated water for a time period on the order of 60 seconds or more. Alternatively, the bladder material may be heated with steam or radiant heat, by injecting heated fluid into the bladder, or by injecting heated air into an empty bladder before fluid injection. In each case the initial stress is quickly relieved, substantially eliminating a potential source of error in the sensed weight.