Switch flap, e.g. twisting flap or shaft, damage detection device, used in motor vehicle component, has electronic device to detect change in surface coating resistance of shaft, due to cracks in shaft, when current is applied to coatings

摘要

Damage detection device has an electronic device (22) that is connected with electrically conducting surface coatings of a switch flap shaft. The coatings are applied on the surface of the shaft by metallization or spraying and act as a monitoring unit. The electronic device detects a change in resistance of the coatings, due to occurrence of cracks in the shaft, when an electric current is applied at regular time intervals to the coatings.