Sensor and manufacturing method thereof

Abstract

A temperature sensor comprises a thermistor element, a metal tube into which the thermistor element is inserted, two electrode wires joined to the thermistor element, two lead wires, which are covered by covering tubes with uncovered portions remaining and joined to the electrode wires, respectively, at the uncovered portions, and a housing having an inner hollow space into which the electrode wires and the lead wires are accommodated together with a resin. The sensor further comprises an insulating case disposed inside the housing and provided with a partition section for separating the joined portions of the electrode wires and the lead wires, the electrode wires and the lead wires from each other, and the inside of the insulating case is filled up with resin in a state that an opened end of the metal tube, the electrode wire and portions of the covered lead wires and uncovered portions thereof are inserted in the insulating case.

What is claimed is:  
     
         1 . A sensor comprising: 
 a thermistor element for generating an electric signal;    a metal tube having one opened end and another closed end, into which said thermistor element is inserted;    a plurality of electrode wires joined to the thermistor element so as to project outward over the opened end of the metal tube;    a plurality of lead wires, which are covered by covering tubes with uncovered portions remaining and joined to the electrode wires, respectively, at the uncovered portions;    a housing having an inner hollow space into which the electrode wires and the lead wires are accommodated together with a resin as a filler;    an insulating case disposed inside the housing and provided with a partition section for separating the joined portions of the electrode wires and the lead wires from each other, the respective electrode wires from each other and the respective lead wires from each other; and    an insulating material which is fed to fill inside the insulating case in a state that the opened end of the metal tube and the electrode wires extending therefrom are inserted in the insulating case and portions of the covered lead wires and uncovered portions thereof are also inserted therein.    
     
     
         2 . A sensor according to  claim 1 , wherein said insulating case is formed of a resin material.  
     
     
         3 . A sensor according to  claim 1 , wherein said insulating case is formed from glass.  
     
     
         4 . A sensor according to  claim 1 , wherein said insulating material is an epoxy resin, which constitutes a resin filling layer in the insulating case.  
     
     
         5 . A sensor according to  claim 1 , wherein said insulating case has a cylindrical columnar shape and is composed of divided two case halves, having substantially symmetrical shape, each provided with longitudinal half of inner hollow space.  
     
     
         6 . A sensor according to  claim 1 , wherein said insulating case is provided with a rib member extending in a direction normal to a longitudinal resin flowing direction at a time of feeding the resin in the housing and abutting against an inner peripheral surface of the housing.  
     
     
         7 . A sensor according to  claim 6 , wherein said rib member comprises a plurality of rib pieces which are formed to outer peripheral surfaces of the insulating case at both longitudinal end portions thereof.  
     
     
         8 . A sensor according to  claim 7 , wherein said rib member comprises three rib pieces each having a conical shape.  
     
     
         9 . A sensor according to  claim 7 , wherein said rib member comprises four rib pieces each having a sectorial shape.  
     
     
         10 . A sensor according to  claim 1 , wherein said sensor is a temperature sensor provided for an internal combustion engine of a vehicle for detecting a temperature of an exhaust gas of an exhaust tube of the internal combustion engine.  
     
     
         11 . A method of manufacturing a sensor which generally comprises a thermistor element for generating an electric signal, a metal tube having one opened end and another closed end, into which the thermistor element is inserted, a plurality of electrode wires joined to the thermistor element so as to project outward over the opened end of the metal tube, a plurality of lead wires, which are covered by covering tubes with uncovered portions remaining and joined to the electrode wires, respectively, at the uncovered portions, and a housing having an inner hollow space into which the electrode wires and the lead wires are accommodated together with a resin as a filler, 
 said sensor manufacturing method comprising the steps of;    preparing an insulating case provided with a partition section for separating the joined portions of the electrode wires and the lead wires from each other, the respective electrode wires from each other and the respective lead wires from each other;    inserting the opened end of the metal tube, the electrode wires extending therefrom and portions of the covered lead wires and uncovered portions thereof into the insulating case;    joining the electrode wires and the lead wires to each other;    filling the insulating case with an insulating material;    inserting thereafter the insulating case in the housing; and    filling resin in the hollow space of the housing.    
     
     
         12 . A method of manufacturing a sensor according to  claim 11 , wherein said resin in fed into the housing through an injection molding process.  
     
     
         13 . A method of manufacturing a sensor according to  claim 11 , wherein said insulating case is formed of a resin material.  
     
     
         14 . A method of manufacturing a sensor according to  claim 11 , wherein said insulating case is formed from glass.  
     
     
         15 . A method of manufacturing a sensor according to  claim 11 , wherein said insulating material is an epoxy resin, which constitutes a resin filling layer in the insulating case.  
     
     
         16 . A method of manufacturing a sensor according to  claim 11 , wherein said sensor is a temperature sensor provided for an internal combustion engine of a vehicle for detecting a temperature of an exhaust gas of an exhaust tube of the internal combustion engine.