초록 ▼

An improved mechanical joint structure is provided and adapted for positively retaining a heating element within a bore of a body of a glow plug. The glow plug includes a body, a heating element and a ferrule. The ferrule is sealingly positioned radially between an internal surface of the body bore

An improved mechanical joint structure is provided and adapted for positively retaining a heating element within a bore of a body of a glow plug. The glow plug includes a body, a heating element and a ferrule. The ferrule is sealingly positioned radially between an internal surface of the body bore and a peripheral surface of the heating element. The glow plug further includes a compressing structure for positively compressing an internal surface of the ferrule against the peripheral surface of the heating element in response to the heating element being forced into the body bore by, for example, the gas pressure developed in an operating engine combustion chamber. Unlike conventional brazed or interference joints used in typical glow plugs, the present invention provides a normal force (Fn), for sealing the heating element, and an axially-directed frictional force (Ff), for retaining the heating element, which both increase as the heating element is forced deeper into the body bore.

대표청구항 ▼

A glow plug adapted for an internal combustion engine comprising: a body defining a bore having a tapered internal surface and an opening, said tapered internal surface having a diameter which increases towards the opening of the body bore; an elongated heating element having first and second end po

A glow plug adapted for an internal combustion engine comprising: a body defining a bore having a tapered internal surface and an opening, said tapered internal surface having a diameter which increases towards the opening of the body bore; an elongated heating element having first and second end portions, said first end portion of the heating element having a peripheral surface positioned in the body bore in spaced relation to the internal surface of the body bore, said second end portion of the heating element being positioned outside of the body bore opening; a ferrule sealingly positioned radially between the internal surface of the body bore and the peripheral surface of the heating element, said ferrule having a tapered peripheral surface and defining a main bore having an internal surface, said tapered peripheral surface of the ferrule being complementary relative to the tapered internal surface of the body bore, said tapered peripheral surface of the ferrule being connected to the tapered internal surface of the body bore by an interference fit; and compressing means for radially-inwardly compressing the internal surface of the ferrule against the peripheral surface of the first end portion of the heating element in response to the heating element being forced into the body bore, said compressing means including a shoulder formed on the first end portion of the heating element and a shoulder formed in the main bore of the ferrule, said shoulder of the heating element engaging the shoulder of the ferrule.