PRECHAMBER SPARK PLUG AND A METHOD FOR PRODUCING THE SAME

The invention relates to a prechamber spark plug comprising a housing (3), an insulator (1) with an internal central electrode (2), a prechamber (15) in the front housing region, at least one overflow duct to the combustion chamber of an internal combustion engine, in addition to a device for forming a spark gap. Said device is provided substantially inside the prechamber (15) and contains in particular a central electrode (2) and at least one additional electrode (13) that is fixed to the central electrode (2) and is directed towards the cylinder wall (12). According to the invention, the insulator (1) is braced between at least one front and one rear shoulder (19, 23) in order to fix it in the housing (3). The aim of the invention is to significantly improve the mechanical and thermal characteristics of a prechamber spark plug of this type, thus guaranteeing in particular a permanent, impervious fixing method for the insulator in the housing and the central electrode in the insulator during long-term operation. To achieve this, the insulator (1) has two annular collars (16, 17), which are used to clamp the insulator between the shoulders (19, 23) in the housing (3) with a predetermined high prestressing force in an axial direction, said prestress being in effect dimensionally stable in the vicinity of the shoulders (19, 23), in such a way that a positive fit is formed, the required elastic expansion in the essentially cylindrical section of the housing being provided.