KNOCK SENSOR

摘要

PURPOSE:To prevent a short circuit without invading a weld dust into a box body by fitting the opening end of the box body of a sensor with the lower face of the upper lid plate and welding together in the knock sensor used for the internal-combustion engine of automobile, etc. CONSTITUTION:A lid plate 20 is provided on the box body 1 of a knock sensor and the vibration of an engine is received by an additional weight 8 via a screw 15 and a knocking is sensed by pushing a piezoelectric ceramic. A projection like part 30 is provided as well on the annular step 29 which is formed on the inside of the opening end of the upper part of the box body 1. A projection 31 is also formed on the lower face of the lid plate 20. The projection 31 is fitted into the annular step 29 and the box body 1 and lid plate 20 are made in contact and a ring projection welding is performed on the whole periphery. Since the annular step 29 and projection are completely engaged the invasion of the weld dust into the gap of the box body during welding is therefore prevented and a short circuit can be prevented.