Manufacturing method of ceramic heater-type glow plug, and ceramic heater-type glow plug

Abstract

A manufacturing method of a ceramic heater-type glow plug including: a ceramic heater; and a metallic outer cylinder, one end of which holds the ceramic heater and the other end of which is fixed to a housing has: a step of forming a metallized layer on at least a portion of a surface region in the ceramic heater that is held by the outer cylinder; a step of press-inserting at least the metallized layer of the ceramic heater in the outer cylinder; and a step of heating the ceramic heater and the outer cylinder at a temperature at which a material for forming the metallized layer becomes a semi-molten state and performing joining by mass transfer between the outer cylinder and a solid layer of the metallized layer.

1 . A method for manufacturing a ceramic heater-type glow plug including: a ceramic heater; and a metallic outer cylinder, one end of which holds the ceramic heater and an other end of which is fixed to a housing, the manufacturing comprising:
 forming a metallized layer on at least a portion of a surface region in the ceramic heater that is held by the outer cylinder;   press-inserting at least the metallized layer of the ceramic heater in the outer cylinder; and   heating the ceramic heater and the outer cylinder at a temperature at which a material for forming the metallized layer becomes a semi-molten state and performing joining by mass transfer between the outer cylinder and a solid layer of the metallized layer.   
     
     
         2 . The method according to  claim 1  further comprising
 applying silver plating to a region in the outer cylinder that is joined to the metallized layer before joining the outer cylinder and the ceramic heater. 
 
     
     
         3 . The method according to  claim 1  wherein
 forming the metallized layer includes using silver paste containing: copper that occupies 30% or lower; and titanium that occupies 10% or lower, with respect to total weight of the metallized layer. 
 
     
     
         4 . The method according to  claim 1  further comprising
 forming an oxidation resistant layer by a material having an oxidation resistance property on a connection portion in lead wire, which energizes the ceramic heater, to the ceramic heater. 
 
     
     
         5 . The method according to  claim 4  characterized in that
 the material having the oxidation resistance property is silver or nickel. 
 
     
     
         6 . The method according to  claim 1  further comprising
 brazing the lead wire, which energizes the ceramic heater, and the ceramic heater at the same time as joining by the mass transfer between the outer cylinder and the solid layer of the metallized layer. 
 
     
     
         7 . The method according to  claim 6  further comprising
 caulking the outer cylinder and fixing the lead wire to the outer cylinder after brazing the lead wire and the ceramic heater. 
 
     
     
         8 . The method according to  claim 1  further comprising
 caulking the outer cylinder in a state where the lead wire, which energizes the ceramic heater, is pressed against the ceramic heater, fixing the lead wire to the outer cylinder, and connecting the lead wire to the ceramic heater. 
 
     
     
         9 . The method according to  claim 7  further comprising
 providing a heat resistant resin on a surface of the lead wire that opposes a caulked portion of the outer cylinder. 
 
     
     
         10 . The method according to  claim 7  further comprising
 knurling the surface of the lead wire that opposes the caulked portion of the outer cylinder. 
 
     
     
         11 . A ceramic heater-type glow plug including: a ceramic heater; and a metallic outer cylinder, one end of which holds the ceramic heater and the other end of which is fixed to a housing, wherein
 the ceramic heater has a metallized layer on at least a portion of a surface region that is held by the outer cylinder, and   the ceramic heater and the outer cylinder are joined by press-inserting the metallized layer of the ceramic heater in the outer cylinder and heating the ceramic heater and the outer cylinder at a temperature at which a material for forming the metallized layer becomes a semi-molten state, so as to achieve mass transfer between the outer cylinder and a solid layer of the metallized layer.   
     
     
         12 . The ceramic heater-type glow plug according to  claim 11  characterized in that
 silver plating is applied to a region in the outer cylinder that is joined to the metallized layer. 
 
     
     
         13 . The ceramic heater-type glow plug according to  claim 11  characterized in that
 the metallized layer is formed of silver paste containing: copper that occupies 30% or lower; and titanium that occupies 10% or lower, with respect to total weight of the layer. 
 
     
     
         14 . The ceramic heater-type glow plug according to  claim 11  characterized in that
 an oxidation resistant layer by a material having an oxidation resistance property is provided on a connection portion at a tip of lead wire, which energizes the ceramic heater, to the ceramic heater. 
 
     
     
         15 . The ceramic heater-type glow plug according to  claim 14  characterized in that
 the material having the oxidation resistance property is silver or nickel. 
 
     
     
         16 . The ceramic heater-type glow plug according to  claim 11  characterized in that
 a lead wire, which energizes the ceramic heater, is provided, and 
 the lead wire is fixed to the outer cylinder by caulking of the outer cylinder. 
 
     
     
         17 . The ceramic heater-type glow plug according to  claim 16  characterized in that
 a heat resistant resin is provided on a surface of the lead wire that opposes a caulked portion of the outer cylinder. 
 
     
     
         18 . The ceramic heater-type glow plug according to  claim 16  characterized in that
 a surface of the lead wire that opposes the caulked portion of the outer cylinder is knurled.