Glow tube, in particular for a sheathed-element glow plug

Abstract

A glow tube, in particular for a sheathed-element glow plug. The glow tube, which has a dome-shaped, closed end section ( 27 ) and a cylindrical, open end section ( 28 ), is composed of at least two axially serially disposed glow tube parts. The one glow tube part is formed at the closed end section ( 27 ) by a seamless glow tube cap ( 31 ), and the other glow tube part is formed at the open end section ( 28 ) by a substantially cylindrical glow tube extension ( 32 ).

1 - 7 . (canceled) 
     
     
         8 . A glow tube for a sheathed-element glow plug, having a dome-shaped closed end section and a cylindrical open end section, the glow tube comprising: at least two glow tube parts, wherein one glow tube part is formed at the closed end section by a seamless glow tube cap, and the other glow tube part is formed at the open end section by a substantially cylindrical glow tube extension. 
     
     
         9 . The glow tube as recited in  claim 8 , wherein a joint is formed between the glow tube cap and the glow tube extension, and the joint is situated at a location of the glow tube that is subject to less thermal stress than the major portion of the glow tube cap. 
     
     
         10 . The glow tube as recited in  claim 9 , wherein the joint is formed by an annular end face formed on the glow tube cap and another annular end face formed on the glow tube extension. 
     
     
         11 . The glow tube as recited in  claim 9 , wherein the glow tube cap and the glow tube extension are joined at the joint in an integral bond. 
     
     
         12 . The glow tube as recited in  claim 10 , wherein the glow tube cap and the glow tube extension are joined at the joint in an integral bond. 
     
     
         13 . The glow tube as recited in  claim 8 , wherein the glow tube cap has a closed dome and a substantially cylindrical section, and the axial length of the cylindrical section is, at a maximum, eight times the diameter of the cylindrical section following the hammering process used for the glow tube. 
     
     
         14 . The glow tube as recited in  claim 9 , wherein the glow tube cap has a closed dome and a substantially cylindrical section, and the axial length of the cylindrical section is, at a maximum, eight times the diameter of the cylindrical section following the hammering process used for the glow tube. 
     
     
         15 . The glow tube as recited in  claim 10 , wherein the glow tube cap has a closed dome and a substantially cylindrical section, and the axial length of the cylindrical section is, at a maximum, eight times the diameter of the cylindrical section following the hammering process used for the glow tube. 
     
     
         16 . The glow tube as recited in  claim 8 , wherein the glow tube cap and the glow tube extension are made of different materials. 
     
     
         17 . The glow tube as recited in  claim 9 , wherein the glow tube cap and the glow tube extension are made of different materials. 
     
     
         18 . The glow tube as recited in  claim 10 , wherein the glow tube cap and the glow tube extension are made of different materials. 
     
     
         19 . The glow tube as recited in  claim 13 , wherein the glow tube cap and the glow tube extension are made of different materials. 
     
     
         20 . The glow tube as recited in  claim 8 , wherein the glow tube cap is produced by deepdrawing, MIM (metal injection molding), powder extrusion, metal injection casting or by machining. 
     
     
         21 . The glow tube as recited in  claim 9 , wherein the glow tube cap is produced by deepdrawing, MIM (metal injection molding), powder extrusion, metal injection casting or by machining. 
     
     
         22 . The glow tube as recited in  claim 10 , wherein the glow tube cap is produced by deepdrawing, MIM (metal injection molding), powder extrusion, metal injection casting or by machining. 
     
     
         23 . The glow tube as recited in  claim 13 , wherein the glow tube cap is produced by deepdrawing, MIM (metal injection molding), powder extrusion, metal injection casting or by machining.