Glow Plug Head And Corresponding Piezo-Electric Pressure Sensor

Abstract

A glow plug includes a pressure sensor mounted within a tubular member ( 8 ) and held in the tubular member ( 8 ) by a bearing member. The bearing member is held in the tubular member ( 8 ) by plastic deformation ( 52 ) of the wall of the tubular member.

1 . A glow plug ( 2 ) comprising a pressure sensor ( 14 ) mounted within a tubular member ( 8 ) and held in said tubular member ( 8 ) by means of a bearing member ( 50 ), 
 characterized in that the bearing member ( 50 ) is held in the tubular member ( 8 ) by plastic deformation of the wall ( 46 ) of the tubular member.    
   
   
       2 . A glow plug according to  claim 1 , characterized in that the bearing member ( 50 ) is held in place by crimping.  
   
   
       3 . A glow plug according to  claim 1 , characterized in that the bearing member ( 50 ) has, at least over a portion of its periphery, a frusto-conical surface, the large diameter base of the frustum being oriented towards the pressure sensor ( 14 ).  
   
   
       4 . A glow plug according to  claim 1 , characterized in that the pressure sensor ( 14 ) is a piezoelectric sensor comprising a piezoelectric member ( 18 ) mounted between two contact members ( 20 ), and in that the piezoelectric member ( 18 ) has an annular form having a flat ( 56 ) on its periphery.  
   
   
       5 . A glow plug according to  claim 4 , characterized in that the piezoelectric member ( 18 ) and the contact members ( 20 ) are arranged substantially transversally in the tubular member ( 8 ), in that the contact members ( 20 ) each have a connection tab ( 58 ) at their periphery extending substantially longitudinally with respect to the tubular member ( 8 ), and in that the connection tabs ( 58 ) are arranged in front of the flat ( 56 ) of the piezoelectric member ( 18 ).  
   
   
       6 . A glow plug according to  claim 1 , characterized in that the tubular member ( 8 ) comprises a substantially circular cylindrical inner wall.  
   
   
       7 . A glow plug according to  claim 1 , characterized in that the tubular member ( 8 ) receiving the pressure sensor ( 14 ) is a tubular body ( 8 ) enabling the glow plug ( 2 ) to be fixed in the cylinder head ( 6 ) of the internal combustion engine.  
   
   
       8 . A glow plug according to  claim 7 , characterized in that the tubular body ( 8 ) is fixed in the cylinder head ( 6 ) by screwing and comprises a gripping zone ( 54 ) of hexagonal transverse section to facilitate its screwing and unscrewing, and in that the plastic deformation enabling the bearing member ( 50 ) to be held in place is carried out adjacent to the gripping zone ( 54 ).  
   
   
       9 . An internal combustion engine, in particular of the Diesel engine type, characterized in that it comprises at least one glow plug ( 2 ) according to  claim 1 .  
   
   
       10 . A method of mounting a pressure sensor ( 14 ) in the head of a glow plug ( 2 ), in which the sensor is installed in a housing ( 48 ) of adapted form then held by means of a bearing member ( 50 ), characterized in that the holding in place of the bearing member ( 50 ) is achieved by plastic deformation of the wall ( 46 ) of the housing ( 48 ) receiving the sensor and the bearing member ( 50 ).  
   
   
       11 . A glow plug according to  claim 2 , characterized in that the bearing member ( 50 ) has, at least over a portion of its periphery, a frusto-conical surface, the large diameter base of the frustum being oriented towards the pressure sensor ( 14 ).  
   
   
       12 . A glow plug according to  claim 2 , characterized in that the pressure sensor ( 14 ) is a piezoelectric sensor comprising a piezoelectric member ( 18 ) mounted between two contact members ( 20 ), and in that the piezoelectric member ( 18 ) has an annular form having a flat ( 56 ) on its periphery.  
   
   
       13 . A glow plug according to  claim 3 , characterized in that the pressure sensor ( 14 ) is a piezoelectric sensor comprising a piezoelectric member ( 18 ) mounted between two contact members ( 20 ), and in that the piezoelectric member ( 18 ) has an annular form having a flat ( 56 ) on its periphery.