JP2008134219A - Gas sensor and related manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas sensor with a reliable and easily-attachable structure, enables its functions and qualities such as air permeability, insulation, response, sealing and the like to be tested in the middle of the manufacturing process of the gas sensor. <P>SOLUTION: The gas sensor includes a detecting unit 10 including a concentration detecting element 140 composed of a bottom-closed cylindrical solid electrolyte body 141 which has inner and outer walls formed with electrodes 142, 143, and a housing 150 and output terminals 111, 121, and includes an output extracting unit 20 including at least signal wires 200, 210, power conducting wires 220, 230, output extracting terminals 202, 212, an insulator 240 and a casing 260. The detecting unit 10 and the output extracting unit 20 are coupled to each other in the insulator 240 by keeping the output terminals 111, 121 in a continuity with the output extracting terminals 202, 212 within the insulator 240. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a structure and manufacturing method of a gas sensor that detects the concentration of a specific gas component in exhaust gas such as an automobile engine, and is particularly suitable for a cup-type gas sensor.

  Conventionally, a gas sensor for detecting the concentration of a specific gas component such as oxygen contained in the exhaust gas is disposed in an exhaust gas flow path of an internal combustion engine such as an automobile engine, and the air-fuel ratio or the like is calculated from the detected concentration of the specific gas component. Calculation and combustion control of the internal combustion engine is performed.

  As such a gas sensor, an oxygen concentration detection element in which an electrode layer such as platinum is applied to the inner and outer surfaces of a solid electrolyte body formed of an oxygen ion conductive material such as zirconia in a bottomed cylindrical shape, and the oxygen concentration detection element An oxygen sensor or the like that includes an inserted heater for heating the oxygen concentration detection element, output extraction means for taking out the output from the oxygen concentration detection element, and energization means for energizing the heater is widely used. .

  By the way, along with intensifying price competition in the automobile industry in recent years, to develop a sensor structure and manufacturing method advantageous in reducing the number of parts and simplifying the assembly process while improving the reliability of this type of gas sensor. Is an important key to cost reduction.

  For example, FIG. 2 of Patent Document 1 shows an oxygen sensor element 2, a metal shell 3 that holds the oxygen sensor output element 2, an oxygen sensor element 2, and a gas sensor that is highly reliable and easy to manufacture and a method for manufacturing the gas sensor. One or a plurality of sensor terminal fittings 16, 17 that are electrically conductive and extend from the oxygen sensor element 2 to the rear end side, a metal outer cylinder 21 that is connected to the metal shell 3 at its front end, and a metal outer cylinder 21 It has an electrically insulating separator 31 housed inside, and a collar 34 of the separator 31 is formed with an outer cylinder abutting surface 34a, and the metal outer cylinder 21 is a collar part abutting against the outer cylinder abutting surface 34a. An oxygen sensor is disclosed in which the contact surface 24b is a slope that is located radially outward from the front end side, and the separator 31 is held by the metal outer cylinder 21 in a state of being biased to the rear end side. Yes.

  According to the sensor manufacturing method described in Patent Document 1, the stress acting between the sensor terminal member and the concentration detection element due to the positional deviation or posture deviation of the sensor terminal member is alleviated, and the destruction of the concentration detection element or the sensor terminal member It is possible to prevent problems such as breakage of the sheet.

  Further, in the gas sensor described in Patent Document 1, as shown in FIG. 4 of Patent Document 1, the heater 15 is a rod-shaped ceramic heater, and a heating part 15a having a resistance heating element in a core material mainly composed of alumina is formed. When the heater 15 is energized through the heater terminal fittings 16 and 17 and the heater lead wires 18 and 19 brazed to the electrode pads 15e and 15f, the tip of the oxygen concentration detection element 2 is heated. The heater terminal fitting 17 has a connector portion 17 a that holds the core wire of the heater lead wire 18 and electrically connects the heater terminal fitting 17 and the heater lead wire 18.

  For this reason, as shown in FIGS. 7 and 8 of Patent Document 1, the first sensor terminal fitting 11, the second sensor terminal fitting 12, the heater 15, and the heater lead wires 18 and 19, which take out the signal of the sensor element 2, Instead of being connected to the element 2 side, the heater 15 is inserted into the sensor element 2 after being assembled in advance in the separator 31 and placed in the metal outer cylinder 21, so that the heater 15 and the sensor terminal fitting 11 are inserted. , 12 is buffered to prevent breakage of the heater 15 during assembly and breakage of the connection portion with the sensor output lead wires 13 and 14 during assembly.

In Patent Document 2, a ceramic separator and a fitting are assembled in advance inside a cover member having a vent hole for introducing air as a reference gas into the sensor, and the cover member is inserted into a casing in which the sensor element is assembled. An oxygen sensor is disclosed that enables the fitting of the connecting fitting to the sensor element.
JP 2004-53425 A JP 2000-193629 A

  However, in the structure and manufacturing method of the conventional gas sensor disclosed in Patent Document 1, as shown in FIG. 7 of Patent Document 1, the heater terminal fittings 16 and 17 are brazed to the heater electrode pads 15e and 15f. Must be provided not on the sensor element 2 side but on the separator 31 side. Further, as shown in FIG. 8 of Patent Document 1, when the heater 15 is inserted into the sensor element 2, the heater 15 must be inserted while being gripped by a special chuck mechanism CH in order to prevent the heater 15 from being damaged. Rather, the assembly process is complicated.

Similarly to the heater 15, the sensor terminal fittings 11 and 12 are connected not to the sensor element 2 side but to the separator 31 side. The sensor terminal fittings 11 and 12 are connected to the lead wires 13 and 14 by connecting portions 11 a and 12 a. It is fixed to the separator 31 via the lead wires 13 and 14, and is only elastically held by the separator 31 at the separator contact portions 11b and 12b.
On the other hand, the insertion part 11c of the first sensor fitting 11 is inserted while pressing the bottomed hole 2a of the oxygen sensor 2 in order to ensure conduction with the sensor internal electrode 2c. Power is considered to work.
Further, the insertion portion 12c of the second sensor fitting 12 is normally formed with an inner diameter smaller than the outer diameter of the sensor element 2 in order to ensure conduction with the sensor external electrode 2f, and the sensor 12 is elastically Since the element 2 is gripped, it is considered that a relatively large frictional force acts on the insertion portion 12 c even when the second sensor fitting 12 is fitted to the sensor element 2.
Therefore, when the sensor terminal fittings 11 and 12 are assembled to the sensor element 2, a resistance force is applied by the frictional force, and the lead wires 13 and 14 are not covered immediately above the connector portions 11a and 12a of the lead wires 13 and 14. Therefore, there is a risk that the weakly rigid portion will bend and break.
Alternatively, in order to prevent such buckling, the urging force of the connecting portion of the sensor fittings 13 and 14 is set so that the sensor fittings 11 and 12 hanging from the lead wires 13 and 14 can be easily inserted into the oxygen sensor 2. I think it must be weakened.
Accordingly, there is a possibility that the contact between the sensor fittings 11 and 12 and the electrodes 2c and 2f inside and outside the sensor is incomplete.

  Moreover, since it will be covered with the metal outer cylinder 21, the mounting state of the sensor terminal fittings 11 and 12 cannot be confirmed, and whether the sensor terminal fittings 11 and 12 are normally attached to the sensor element 2 or not. I can't confirm. Furthermore, since the heater 15 is assembled on the separator 31 side and the sensor element 2 is assembled to the metal shell 3 without mounting the sensor terminal fittings 11 and 12, the function of the sensor element 2 performed while being heated by the heater 15, Quality confirmation or the like cannot be performed unless the cover member 21 is attached to the casing 3 in which the sensor element 2 is assembled and the gas sensor is almost completed. In addition, since the sensor terminal fittings 11 and 12 are fitted in the state where the sensor element 2 is assembled to the metal shell 3, the portion of the sensor element 2 to which the sensor terminal metal fittings 11 and 12 are connected is exposed from the metal shell 3. Therefore, the size of the sensor element 2 is increased.

  Similarly, in the oxygen sensor described in Patent Document 2, the heater and the sensor connection fitting are attached to the cover member side, and the sensor element is attached to the casing in a state where the sensor connection fitting is not attached. The sensor connection fitting cannot be pushed into and attached to the sensor element unless it is simultaneously attached to the casing. Therefore, similarly to the gas sensor described in Patent Document 1, the function evaluation of the sensor element cannot be performed during the manufacturing process.

  In addition, in the conventional gas sensor structure and manufacturing method, it is difficult to confirm the air permeability of the air introduction part that introduces air as a reference gas because the heater is assembled in advance to the air introduction part.

  The present invention has been made in view of such circumstances, and in the course of the manufacturing process of the gas sensor, air permeability of the air introduction part, insulation of the signal extraction part, function such as responsiveness / sealability of the concentration detection element, quality, etc. Therefore, it is possible to provide a gas sensor having a structure in which the inspection can be easily performed, the assembly is easy, and the signal extraction unit and the sensor unit after the assembly are highly reliable, and the manufacturing method thereof.

According to the first aspect of the present invention, the ion conductive solid is formed in a bottomed cylindrical shape with a closed end, a reference electrode layer in contact with the reference gas is formed on the inner side, and a measurement electrode layer in contact with the gas to be measured is formed on the outer side. A cup type gas sensor comprising an electrolyte body and having a concentration detecting element for detecting the concentration of a specific gas component in a gas to be measured,
At least the concentration detection element, a housing for supporting and fixing the concentration detection element in the gas flow path to be measured, a reference electrode output terminal extending from the reference electrode layer, and a measurement extending from the measurement electrode layer A detection unit comprising a pair of output terminals comprising an electrode output terminal, at least a pair of signal lines connected to an external control device, and a pair of output extraction terminals connected to the pair of signal lines Insulating and sealing the insulator that holds the pair of output extraction terminals in insulation, the substantially cylindrical casing that protects the insulator, and the pair of signal wires and the pair of energization wires at the rear end of the casing An output extraction unit comprising a sealing member and a ventilation part for introducing air into the casing, and in the output terminal insertion hole provided in the insulator, Allowed conduction power terminals and the output extracting terminals and allowed coupling the said detection unit and the output extracting unit.

According to the invention of claim 1, before assembling the detection unit and the output take-out unit, the output responsiveness of the detection unit, the air permeability and the insulation of the output take-out unit are inspected, and there is a problem in the manufacturing process. Since it can be discovered, the reliability of the gas sensor as a finished product can be dramatically improved while eliminating waste of materials and the like.
Further, since the output terminal is connected to the output extraction terminal fixed to the insulator in the insulator, there is no possibility of disconnection due to external vibration or the like. Therefore, the quality as a gas sensor improves.

  According to a second aspect of the present invention, the detection unit includes a heater that generates heat when energized, and the output extraction unit includes a pair of energization wires connected to an external power feeding device and a pair of energizations connected to the pair of energization wires. A pair of terminals, and the pair of energized terminals are insulated and held in the insulator.

  According to the invention of claim 2, quality confirmation such as responsiveness can be performed while the detection unit is heated by the heater. Moreover, the insulation state of the output extraction unit can be confirmed. Therefore, even in the gas sensor equipped with the heater, each unit can be inspected before the assembly of the detection unit and the output extraction unit, and defects can be found in the manufacturing process. As a result, the reliability of the gas sensor can be dramatically improved.

  In the invention of claim 3, the heater electrode provided on the surface of the heater is electrically connected to the energizing terminal in the heater insertion hole provided in the insulator.

  According to invention of Claim 3, since the said heater electrode is connected in the said insulator with the said electricity supply terminal fixed to the said insulator, there is no possibility of a disconnection by the vibration etc. from the outside. Therefore, the quality as a gas sensor improves.

  According to a fourth aspect of the present invention, one of the output terminal and the output extraction terminal is a substantially U-shaped spring-like terminal made of an elastic metal material, and the other is a plate-like terminal.

  According to the invention of claim 4, the output terminal and the output extraction terminal are brought into contact and conduction elastically. Since the plate-like terminal is always elastically pressed and connected by the spring-like terminal, conduction between the two is not interrupted by vibration of the vehicle or the like. Therefore, the reliability as a gas sensor is further improved.

  In the invention of claim 5, at the contact surface between the spring-like terminal and the plate-like terminal, one of the spring-like terminal and the plate-like terminal has a flat cross section, and the other is convex toward the other. Having an arc cross section.

  According to the invention of claim 5, since one of the contact surfaces of the output terminal and the output lead-out terminal has a flat cross-sectional shape and the other has a circular cross-sectional shape, the assembly position of one of the terminals is shifted from the center. Even in this case, both terminals are surely brought into contact with each other at one point or in a straight line. Therefore, the reliability as a gas sensor is further improved.

  In the invention of claim 6, the energizing terminal is a substantially U-shaped spring-like terminal made of an elastic metal material.

  According to invention of Claim 6, the said heater electrode and the said electricity supply terminal are contact-conductive elastically. Since the heater electrode is always elastically pressed and connected by the spring-like terminal, conduction between the two is not interrupted by vibration of the vehicle or the like. Therefore, the reliability as a gas sensor is further improved.

  According to a seventh aspect of the present invention, the output terminal insertion hole has an insertion hole inclined portion that guides insertion of the output terminal.

  According to the invention of claim 7, even if the output terminal is disposed in an inclined state, the output terminal is caused along the insertion hole inclined portion when the output terminal is inserted into the insertion hole. Therefore, the connection between the output terminal and the output extraction terminal can be performed in a stable state. Therefore, the reliability of the gas sensor is further improved.

  According to an eighth aspect of the present invention, the output terminal insertion hole has an insertion hole protrusion that contacts the plate-like terminal.

  According to the invention of claim 8, since the plate-like terminal is supported by the insertion hole protrusion when elastically pressed by the spring terminal, the plate-like terminal contacts without being bent in the pressing direction. Conductivity is more reliable. Therefore, the reliability of the gas sensor is further improved.

  In the invention according to claim 9, in the insulator, the pair of output extraction terminals facing each other and the pair of energization terminals facing each other are placed in a substantially orthogonal direction.

  According to the ninth aspect of the present invention, the insulator, the heater, and the output terminal are pressed from four directions by the elasticity of the terminal, and the vibration caused by the external vibration applied to the insulator can be absorbed. Therefore, the conduction connection between the output terminal and the output extraction terminal and the conduction connection between the conduction terminal and the heater electrode are always ensured. Therefore, the reliability of the gas sensor is further improved.

  In the invention of claim 10, the ion conductive solid electrolyte material is formed in a closed bottomed cylindrical shape, the reference electrode layer in contact with the reference gas is formed inside, and the measurement electrode layer in contact with the gas to be measured is formed outside. In a method of manufacturing a cup-type gas sensor having a concentration detection element for detecting a concentration of a specific gas component in a gas to be measured, a reference electrode fitting having a reference electrode output terminal and a reference electrode connection portion is provided as the concentration detection element. A measurement electrode fitting having a measurement electrode output terminal and a measurement electrode connection portion is fitted to the measurement electrode, and the concentration detecting element is inserted and fixed in a substantially cylindrical housing via a fixing member. A detection unit including at least a pair of output terminals of the reference electrode terminal and the measurement electrode terminal and the housing, wherein the pair of output terminals is exposed above the housing. The output unit forming step and the pair of output extraction terminals are attached to the insulator, the pair of signal lines are connected to the pair of output terminals, and the pair of signal lines are inserted into a sealing member provided with a plurality of insertion holes. Forming an output take-out unit that houses these in a substantially cylindrical casing and forms an output take-out unit comprising at least the signal line, the output take-out terminal, the insulator, the casing, and the sealing member. A terminal fitting forming step in which one of the output terminal and the output lead-out terminal is formed into a substantially U-shaped spring shape using an elastic metal material and the other is formed into a plate shape; and the detection At the same time that the unit is inserted into the output extraction unit, the output terminal and the output extraction terminal are elastically conducted in the output terminal insertion hole provided in the insulator. It includes a gas sensor assembly steps to complete the gas sensor.

According to the invention of claim 10, since the assembly of the detection unit and the assembly of the output take-out unit can be performed separately and independently, it is easy to check the quality of each unit and the assembly of the detection unit. In this case, the center of all the components can be arranged on the same axis, and a simple process can be realized by assembling in accordance with the order, so that the assembly of the detection unit is extremely easy.
Further, since the assembly process of the output take-out unit is a process of only component insertion and pressure bonding, rationalization is extremely easy.
Therefore, it is possible to provide a gas sensor that is extremely reliable, easy to manufacture, and highly cost competitive.
In addition, since the reference electrode connection portion and the measurement electrode connection portion can be accommodated in the housing, the portion connected to the reference electrode connection portion and the measurement electrode connection portion of the concentration detection element is There is no need to expose from the housing, and the size of the gas sensor can be reduced.

  According to the present invention, during the gas sensor manufacturing process, it is possible to inspect functions such as air permeability of the air introduction unit, insulation of the output extraction unit, responsiveness / sealability of the concentration detection element, and quality, and easy assembly. A gas sensor having a highly reliable structure can be provided.

The first embodiment of the present invention will be described in detail.
Fig.1 (a) is sectional drawing which shows the structure of the gas sensor 1 which is the 1st Embodiment of this invention, FIG.1 (b) is arrow sectional drawing in the AA cross section in Fig.1 (a). . In FIG. 1, the upper side is the base end side and the lower side is the front end side. (The same applies to the following drawings unless the direction is specified in particular.)
As shown in FIG. 1, the gas sensor of the present invention includes a detection unit 10 and an output extraction unit 20.
The detection unit 10 includes a concentration detection element 140, a heater 100 that is inserted into the concentration detection element 140 and generates heat when energized, a housing 150 that fixes the concentration detection element 140 in a gas flow path to be measured, and the concentration detection element 140. A pair of output terminal fittings 110, 120 that are extended from the housing and extend to the proximal end side, a fixing member 130 interposed between the concentration detection element 140 and the housing 150, and the gas to be measured of the concentration detection element 140 are exposed. And a cover body 160 that covers a portion to be covered.

In the concentration detection element 140, for example, a reference electrode layer 142 is formed inside a solid electrolyte body 141 formed in a bottomed cylindrical shape whose tip is closed with an oxygen ion conductive material such as zirconia, and a measurement electrode layer is formed outside. 143 is formed, and a solid electrolyte body engaging portion 144 having a large diameter is formed in the middle of the solid electrolyte body 141.
A reference electrode fitting 110 is inserted inside the concentration detection element 140, and the reference electrode layer 142 and the reference electrode connection portion 112 are electrically connected.
Further, a reference electrode terminal 111 extending toward the base end side is formed on the reference electrode connecting portion 112, and a heater gripping portion 113 is formed on the distal end side of the reference electrode connecting portion 112.

In the heater 100, a heating element 103 (not shown) is built in the front end of a heater base 104 formed of a ceramic material such as alumina in the shape of a long axis, and a pair of lead wires (not shown) connected to the heating element 103 is a heater base 104. Is electrically connected to a pair of heater electrodes 101 and 102 formed on the surface of the electrode.
The heater 100 is inserted into the concentration detection element 140 and is elastically fixed by the heater grip 113.

  A housing engaging portion 151 is formed in the housing 150, and the solid electrolyte body engaging portion 144 and the housing engaging portion 151 are engaged via the metal buffer member 131, so that the concentration detection element 140 is inside the housing 150. In addition, the gap between the concentration detection element 140 and the housing 150 is further filled with an insulating powder 132 such as talc, an insulating powder molded body 133, an insulating sealing member 134 such as ceramic or glass, It is filled with a density detecting element fixing member 130 constituted by an elastic packing 135 made of a metal elastic member, etc., and a housing caulking portion 154 at the upper edge of the housing 150 is caulked to fix the density detecting element 140 in the housing 150. It is united.

  The output extraction unit 20 is electrically connected to a pair of output extraction terminals 202 and 212, a pair of signal lines 200 and 210 that conduct to the output extraction terminals 202 and 212, a pair of energization terminals 222 and 232, and an energization terminal 222 and 232. A pair of conducting wires 220, 230, an insulator 240, an insulator holding metal fitting 250, a casing 260, connection fittings 201, 211, 221, 231; a filter support member 270; a water repellent filter 272; and a sealing member 273 ( Upper bush) and 274 (lower bush).

The output extraction terminals 202 and 212 and the current-carrying terminals 222 and 232 are fixed in an insulated state by an insulator 240, and an end portion on the base end side is exposed from the insulator 240, and is connected via connection fittings 201, 211, 221, and 231. Are connected to the signal lines 200 and 210 and the conductive lines 220 and 230, respectively.
The insulator 240 has an output terminal insertion hole 241 (a, b) and a heater insertion hole 245 formed therein.
The output extraction terminals 202 and 212 and the energization terminals 222 and 232 are each formed in a substantially U-shaped spring shape using an elastic metal material, and the distal ends of the output extraction terminals 202 and 212 are output terminal insertion holes 241 (a, b). ) And the leading ends of the energization terminals 222 and 232 are exposed in the heater insertion hole 245.
The output terminals 111 and 121 and the output extraction terminals 202 and 212 are elastically connected in the output terminal insertion holes 241a and 241b, and the heater electrodes 101 and 102 and the energization terminals 222 and 232 are connected in the heater insertion hole 245. Elastically connected.

  The insulator 240 is fixed in the casing 260 by an insulator holding metal fitting 250.

The base end side of the casing 260 is sealed by sealing members 273 (upper bushing) and 274 (lower bushing) formed of an elastic member, and the signal lines 200 and 210 and the energization lines 220 and 230 connected to the outside However, the insulating members 273 and 274 are insulated and supported.
Further, the sealing members 273 and 274 are substantially cylindrical, and a filter support member 270 and a water repellent filter 272 are fitted in the center.
The filter support member 270 has a bottomed cylindrical shape that is closed on the base end side, and a plurality of support member ventilation holes 271 are formed on the side surface. The water repellent filter that permeates the cylindrical gas and blocks the liquid so as to cover the filter support member 270. 272 is fitted. The water repellent filter 272 is a porous body made of a resin such as PTFE (polytetrafluoroethylene).

  A plurality of sealing member ventilation holes 275 are formed in the sealing members 273 and 274 at positions facing the support member ventilation holes 271, and a plurality of casing ventilation holes 264 are formed in the casing 260. It communicates with the pores 275.

  A front end side 263 of the casing 260 is fitted into a boss portion 154 formed in the housing 250 and is fixed by a coupling means 280 such as laser welding.

  The gas sensor 1 is screwed to the measured gas flow channel wall surface 3 via an elastic member 290 such as a spring washer so that the concentration detecting element 140 is exposed to the measured gas flow channel by a screw portion 153 formed in the housing 150. Is done.

Below, the manufacturing method of the gas sensor in the 1st Embodiment of this invention is explained in full detail.
First, a method for manufacturing the detection unit 10 shown in FIG. 2 in the order of (a) to (d) will be described.
A heater 103 made of tungsten or the like (not shown) is formed inside the tip of a heater base 104 formed of a ceramic material such as alumina in the shape of a long axis, and is electrically connected to the heater 103 via a pair of lead wires (not shown). A heater 100 having a pair of heater electrodes 101 and 102 formed on the surface of the substrate 104 is formed.

A bottomed cylindrical solid electrolyte body 141 whose tip is closed with an oxygen ion conductive solid electrolyte material such as zirconia is formed, and a porous reference electrode layer 142 made of platinum or a platinum alloy is formed on the inner surface and the outer surface thereof. The measurement electrode layer 143 is formed to form the concentration detection element 140.
At this time, as shown in FIG. 2A, a solid electrolyte body engaging portion 144 having a large diameter is formed in the middle of the solid electrolyte body 141, and the measurement electrode layer 143 is on the proximal side of the solid electrolyte body 141. Measurement electrode layer connector part 143a formed so as to cover the outer periphery of the upper part, measurement electrode layer measurement part 143c, measurement electrode connector part 143a, and measurement electrode layer measurement part formed on the tip side from solid electrolyte body engagement part 144 You may comprise by the measurement electrode layer lead part 143b which conduct | electrically_connects 143c.

It is made of an elastic metal material such as stainless steel, and is formed in a partially cut-out tubular shape (substantially C-shaped in cross section) having a diameter slightly larger than the inner diameter of the plate-like reference electrode output terminal 111 and the concentration detection element 140 extending to the base end side. A reference electrode fitting 110 is formed which includes a reference electrode connection portion 112 and a heater grip portion 113 formed in a partially cut-out tubular shape (substantially C-shaped in section) having a diameter slightly smaller than that of the heater.
The heater 100 is inserted while the diameter of the heater grip 113 is elastically expanded, and the reference electrode connection portion 112 is inserted into the concentration detection element 140 together with the heater 100 while the diameter is reduced.

A plate-like measurement electrode terminal 121 made of an elastic metal material such as stainless steel and extending to the base end side, and a partially cut-out tube (substantially cross-section) having a diameter slightly smaller than the base end side outer diameter of the deaeration concentration detection element 140 A measurement electrode fitting 120 including a measurement electrode holding part 122 formed in a C shape is formed.
The measurement electrode holding part 122 is inserted into the upper part of the base end side of the concentration detection element 140 on which the measurement electrode 142 is formed while elastically expanding the diameter.

Next, as shown in FIG. 2B, the concentration detecting element 140 is inserted into the substantially cylindrical housing 150 as a fixing member 130 via a metal buffer member 131, and the solid electrolyte body engaging portion 144 and the housing are inserted. The engagement portion 151 is engaged, and the gap between the concentration detection element 140 and the housing 150 is further sealed with, for example, an insulating powder 132 such as talc, an insulating powder molded body 133, an insulating seal such as ceramic or glass. The member 134 is filled with an elastic packing 135 made of an elastic member such as rubber.
A double-cylindrical cover body 160 including a cover inner cylinder 161 and a cover body 163 that protects the portion of the concentration detection element 140 that is exposed to the gas to be measured is attached to the distal end side of the housing 150.

As shown in FIG. 2C, when the opening upper end 154 and the opening lower end 156 of the housing 150 are caulked, a pair of reference electrode terminals 111 and measurement electrode terminals 121 are formed as shown in FIG. The element side unit 10 in which the output terminals 111 and 121 and the heater electrodes 101 and 102 are exposed to the proximal end side of the housing 150 is completed.
In the process shown in FIG. 2, all the components can be assembled side by side with a single axis as the center, so that rationalization is very easy.

Next, a method for manufacturing the output extraction unit 20 shown in FIG. 3 in the order of (a) to (c) will be described.
For example, an insulator 240 formed of a substantially cylindrical shape using an insulating material such as alumina and formed with a plurality of insertion holes 241 and 245 is attached to the insulator holding metal fitting 250, and the output extraction terminals 202 and 212 and energization terminals 232 and 222 are mounted. Are inserted and fixed to the insulator 240. The details of the insulator 240, the output terminals 202 and 212, and the energization terminals 222 and 232 will be described later.

  The casing 260 is made of a metal such as stainless steel, is formed in a substantially cylindrical shape, has a casing diameter small portion 261 having a small diameter on the proximal end side, and a casing diameter large portion 263 in which the distal end side has a large diameter, The diameter changing portion forms a casing locking portion 262 that is substantially horizontal with respect to the shaft center, and an engagement portion 262 that protrudes inwardly on the small diameter portion 261 is formed in the entire circumference or at a plurality of locations. A plurality of casing vent holes 266 that are opened inward are formed.

For example, a pair of signal lines 200 and 210 and a pair of energization lines 220 and 230 inserted in advance from a base end side of the casing 260 through, for example, rubber-made substantially cylindrical sealing members 273 and 275 are inserted, and the signal lines 200 and 210 are inserted. And the leading ends of the conductive wires 220 and 230 are pulled out to the leading end side of the casing 260.
The output extraction terminals 202 and 212 and the signal lines 200 and 210 are crimped and connected using the connection fittings 201 and 211, and the conduction terminals 222 and 232 and the conduction lines 220 and 230 are crimped and connected using the connection fittings 221 and 231. To do.

The sealing members 273 and 275 are inserted until they come into contact with the casing engaging portion 262, and are locked to the casing engaging portion 262.
A bottomed cylindrical filter support member 270 fitted with a water-repellent filter 272 is inserted into filter insertion holes 277 and 278 provided at the axial centers of the sealing members 273 and 275.
The casing vent hole 264 communicates with the sealing member vent holes 274 and 276 provided in the sealing members 273 and 275, and communicates with the support member vent hole 271 provided in the filter support member 270 via the water repellent filter 272. It will be in the state.

  The insulator holding metal fitting 250 held by the insulator 240 is inserted into the casing large diameter portion 263 and held by the insulator holding metal fitting 250 while the signal lines 200 and 210 and the conducting wires 220 and 230 are pulled back to the base end side.

  The casing caulking portions 266 and 267 at two locations of the casing diameter small portion 261 are caulked to fix the signal lines 200 and 210, the energizing wires 220 and 230, the water repellent filter 272, and the filter support member 270 together with the sealing members 273 and 275. Then, the output extraction unit 20 is completed.

When the boss portion 155 of the detection unit 10 is inserted into the casing large diameter portion 263 of the output extraction unit 20 as shown in FIGS. And the heater 100 are inserted into the insertion holes 241a, 241b, and 245 of the insulator 240, the output terminals 111 and 121 and the output extraction terminals 202 and 212 become conductive, and the heater electrodes 101 and 102 and the energization terminals 232 and 222 Becomes conductive.
The gas sensor 1 is completed when the housing boss 155 and the lower end of the casing large diameter portion 263 are welded and fixed, for example, by laser welding or the like.

With reference to FIG. 5, the output extraction terminals 202 and 212, the energization terminals 222 and 232, and the insulator 240, which are the main parts of the present invention, will be described in more detail.
FIG. 5 is a perspective view showing details of the output extraction terminals 202 and 212, energization terminals 222 and 232, and the insulator 240.

The output extraction terminals 202 and 212 are made of an elastic metal material, bent to the proximal end side by the bent portions 204 and 214 on the distal end side, the inclined portions 205 and 215 are inclined toward the axial center of the insulator 240, and the output terminal 111 , 121 are in contact with each other at the contact portions 206 and 216 to be bent again in the radial direction.
Further, the output extraction terminals 202 and 212 are formed with bending locking portions 203 and 213 as locking means for locking when the insulators 240 are mounted.

The current-carrying terminals 222 and 232 are made of an elastic metal material, bent at the proximal end side by bending portions 223 and 233 on the distal end side, the inclined portions 224 and 234 are inclined toward the axial center of the insulator 240, and the heater terminals 101, The contact portions 225 and 235 that are in contact with 102 are formed into a substantially U shape that bends in the radial direction again.
Furthermore, energizing terminal wings 226 and 236 are formed to protrude from both side surfaces as locking means for locking when inserted into the insulator 240.

  FIG. 6A shows the details of the insulator 240 and the state when the output terminals 202 and 212 and the energization terminals 222 and 232 are inserted and fixed in the insulator 240. (B) is an arrow plan view in the AA plane, (c) is an arrow sectional view in the BB plane, (d) is an arrow plan view in the CC plane, and (e) is It is arrow sectional drawing in a DD surface.

As shown in FIG. 6A, the insulator 240 is formed with output terminal insertion holes 241a and 241b for inserting the output extraction terminals 202 and 212, on the base end side of the output terminal insertion holes 241a and 241b. Are formed with terminal locking portions 244a and 244b to which the output lead terminal bending portions 203 and 213 are locked.
The output terminal insertion holes 241a and 241b are formed with protrusions 243a and 243b having a semicircular cross section that protrude toward the output extraction terminals 202 and 212. Further, the distal ends of the protrusions 243a and 243b are Inclined portions 242a and 242b that are inclined toward the center are formed so that the output terminal insertion holes 241a and 241b become wider toward the side.

  As shown in FIGS. 6A to 6E, the heater insertion holes 245 are provided with slit-like energizing terminal locking portions 246a and 246b, and energizing terminal wing portions 226 and 236 are inserted thereinto. 232 is locked.

7A to 7C and 7D to 7F show how the output terminals 111 and 112 and the heater 100 are inserted into the insulator 240. FIG.
As shown in FIG. 7A, even if the output terminals 111 and 112 are mounted in an inclined state, as shown in FIG. 7B, the output terminals 111 and 121 are caused along the inclined portions 242a and 242b. Therefore, the output terminals 111 and 121 and the output extraction terminals 202 and 212 are connected at the correct positions as shown in FIG. Therefore, it is easy to assemble, and reliable continuity between the output terminals 111 and 121 and the output extraction terminals 202 and 212 is ensured.

  Further, as shown in FIGS. 7D to 7F, when the heater 100 is inserted into the insulator 240, the current-carrying terminals 222 and 232 are elastically bent so that the heater 100 is not interrupted and the heater 100 is inserted after the insertion. The electrodes 101 and 102 and the energization terminals 222 and 232 are elastically connected. Therefore, assembly is easy, and reliable continuity between the heater electrodes 101 and 102 and the energization terminals 222 and 232 is ensured.

  Fig.8 (a) is the principal part enlarged view in the arrow cross section in the BB cross section in FIG.7 (c). As shown in FIG. 8A, even if the mounting position of the reference electrode fitting 110 or the measurement electrode fitting 120 is rotated and shifted in the circumferential direction with respect to the concentration detection element 140, the output terminals 111 and 121 are mounted. Has an arc cross section, and the contact portions 206 and 216 of the output extraction terminals 202 and 212 have a flat cross section, so that they always come into contact at one point. Further, since the insertion hole protrusions 243a and 243b are provided with a smaller curvature than the concave surfaces of the output terminals 111 and 121, the concave surface and the insertion hole protrusions 243a and 243b always come into contact at one point. Accordingly, since the pressing force by the springs of the output extraction terminals 111 and 121 is concentrated on the contact point, the output terminals 111 and 121 and the output extraction terminals 202 and 212 are reliably connected.

Further, as shown in FIG. 8B, the pair of current-carrying terminals 222 and 232 which are opposed to each other are elastically pressed so as to sandwich the heater electrodes 101 and 102 from both sides, and the output terminal 111 is arranged in a direction perpendicular to the pair. , 121 are elastically pressed from both sides by a pair of output extraction terminals 202, 212 facing each other.
For this reason, even if the insulator 240 receives vibrations in any direction from the outside, the vibrations are absorbed by the spring-like terminals 202, 212, 222, and 232 that are elastically pressed from four directions, and the continuity at each terminal portion Is secured.
Therefore, the reliability of the gas sensor 1 becomes extremely high.
It should be noted that the distance X between the pressing points of the output terminals 111 and 121 and the output extraction terminals 202 and 212 and the distance Y between the pressing points of the heater electrodes 101 and 102 and the energizing terminals 222 and 232 are within a range that can be accommodated in the insulator 240. It is better to make it as long as possible. Balance is stable and durability is further improved.

FIG. 9 shows an example of an inspection method in the middle of the manufacturing process that can be performed when the present invention is implemented. (A) is a conceptual diagram which shows the example of the inspection method of a detection unit, (b) is a conceptual diagram which shows the example of the inspection method of an output extraction unit.
As shown in FIG. 9 (a), the assembled detection unit 10 is attached to the gas flow channel 3 to be measured which is assumed to be an exhaust gas flow channel, and a known component gas whose concentration is periodically changed is supplied to the gas flow channel 3 as shown in FIG. The electric power from the power source 4 is applied to the heater electrodes 101 and 102 while being controlled by the energization controller 5, and the output from the detection unit 10 is detected by, for example, a potentiometer connected to the output terminals 111 and 121. When detected by the device 6, the pulse response of the detection unit 10 can be evaluated.
As shown in FIG. 9B, the insulation between the casing 260 and the output extraction terminals 202 and 212, the energization terminals 222 and 232, etc. is measured using the insulation meter 7 or the like, or the lower end of the output extraction unit 20 is measured. The quality of the output extraction unit 20 can be evaluated by attaching an exhaust device such as a blower in an airtight manner and evaluating the air permeability with the pressure gauge 8 or the like.
The sealing performance of the detection unit 10 can be evaluated by means using a similar pressure gauge or the like.

  In the above embodiment, the case where the output terminals 111 and 121 are formed in a plate shape and the output extraction terminals 202 and 212 are formed in a spring shape has been described. However, as a similar form, as shown in FIG. The same effect can be obtained by forming the terminals 202c and 212c in a plate shape and forming the output terminals 111c and 113c in a spring shape.

  In the above-described embodiment, the detection unit 10 including the heater 100 has been described. However, when the concentration detection element 140 is not required to be heated and activated by the heater 100 in the high-temperature gas to be measured. Even in a heaterless type gas sensor that does not include the heater 100 to be used, by using the structure of the present invention in which the output terminal is provided on the detection unit side and the output extraction terminal is provided on the output extraction unit side, the assembly is facilitated. Reliability can be improved.

Furthermore, the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention.
For example, in the above embodiment, the case of the oxygen concentration sensor in which the electrode layer is formed on the inner and outer surfaces of the oxygen ion conductive solid electrolyte body as the concentration detection element has been described. However, the present invention provides a plurality of electrode layers in the measurement unit. And a NOx sensor or the like in which a solid electrolyte layer is formed.
In addition, the present invention can appropriately employ the invention (Japanese Patent Application No. 2005-321156) applied to the ventilation part previously filed by the present inventor.

Sectional drawing of the gas sensor in the 1st Embodiment of this invention. The perspective view and sectional drawing which show the manufacturing method of the detection unit in the 1st Embodiment of this invention later on in order of (a)-(d). Sectional drawing which shows the manufacturing method of the output extraction unit in the 1st Embodiment of this invention later on in order of (a)-(c). Sectional drawing which shows the assembly method of the detection unit and output extraction unit in the 1st Embodiment of this invention later on in order of (a)-(b). The perspective view which shows the detail of the insulator which comprises the output extraction means which is the 1st Embodiment principal part of this invention, and an output extraction side terminal. (A) is sectional drawing which shows the state by which the output extraction side terminal of this invention was assembled | attached to the insulator, (b) is an arrow line view in the AA surface in FIG. 5 (a), (c) is a figure. 5 (a) is a cross-sectional view taken along the line BB in FIG. 5A, (d) is a view taken along the line CC in FIG. 5 (a), and FIG. 5 (e) is a view taken along the line DD in FIG. FIG. The principal part sectional view showing the effect in the 1st embodiment of the present invention. FIG. 4 is an enlarged view of a main part in the first embodiment of the present invention, where (a) shows the effect on securing the electrical continuity between the output terminal and the output extraction side terminal, and (b) shows the effect against external vibration. . It is a conceptual diagram which shows the example of the test during a manufacturing process in the 1st Embodiment of this invention, (a) shows the inspection method of a detection unit, (b) shows the inspection method of an output extraction unit. The perspective view which shows other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas sensor 10 Detection unit 100 Heater 101, 102 Heater electrode 110 Reference electrode metal fitting 111 Reference electrode terminal 112 Heater holding part 113 Reference electrode connection part 120 Measurement electrode metal fitting 121 Measurement electrode terminal 122 Measurement electrode connection part 130 Concentration detection element fixing member 140 Concentration Detection element 141 Solid electrolyte body 142 Reference electrode layer 143 Measurement electrode layer 150 Housing 154 Concentration detection element crimping part 155 Boss part 160 Cover body 20 Output extraction unit 200, 210 Signal lines 201, 211, 221, 231 Connection fittings 202, 212 Output extraction terminals 220 and 230 Conducting wires 222 and 232 Energizing terminals 240 Insulators 241a and 241b Output terminal insertion holes 250 Insulator holding fittings 260 Casing 270 Filter support member 271 Support member ventilation holes 272 The water filter 273 and 274 sealing member 275 sealing member vents 280 units welds 290 elastic washer 3 measured gas flow path wall

Claims (10)

A gas to be measured which is formed of an ion conductive solid electrolyte body formed in a cylindrical shape with a closed end and having a reference electrode layer in contact with the reference gas on the inside and a measurement electrode layer in contact with the gas to be measured on the outside A cup-type gas sensor having a concentration detection element for detecting the concentration of a specific gas component therein,
At least the concentration detection element, a housing for supporting and fixing the concentration detection element in the gas flow path to be measured, a reference electrode output terminal extending from the reference electrode layer, and a measurement extending from the measurement electrode layer A detection unit comprising a pair of output terminals composed of electrode output terminals;
At least a pair of signal lines connected to an external control device, a pair of output extraction terminals connected to the pair of signal lines, an insulator for insulatingly holding the pair of output extraction terminals,
A substantially cylindrical casing that protects the insulator; a sealing member that insulates and seals the pair of signal wires and the pair of conductive wires at a rear end portion of the casing; and ventilation that introduces air into the casing. And an output take-out unit comprising
In the output terminal insertion hole provided in the insulator, the output terminal and the output extraction terminal are electrically connected,
A gas sensor, wherein the detection unit and the output extraction unit are combined. The detection unit includes a heater that generates heat when energized,
The output extraction unit includes a pair of energization wires connected to an external power supply device and a pair of energization terminals connected to the pair of energization wires,
The gas sensor according to claim 1, wherein the pair of energization terminals are insulated and held in the insulator.   The gas sensor according to claim 1 or 2, wherein a heater electrode provided on a surface of the heater and the energization terminal are electrically connected in a heater insertion hole provided in the insulator.   4. The device according to claim 1, wherein one of the output terminal and the output extraction terminal is a substantially U-shaped spring-like terminal made of an elastic metal material, and the other is a plate-like terminal. Gas sensor.   The contact surface between the spring-like terminal and the plate-like terminal, wherein one of the spring-like terminal and the plate-like terminal has a flat cross section, and the other has an arc cross section that is convex toward the other. The gas sensor according to any one of 1 to 4.   The gas sensor according to claim 2, wherein the energizing terminal is a substantially U-shaped spring-like terminal made of an elastic metal material.   The gas sensor according to any one of claims 1 to 6, wherein the output terminal insertion hole has an insertion hole inclined portion that guides the insertion of the output terminal.   The gas sensor according to any one of claims 1 to 7, wherein the output terminal insertion hole has an insertion hole protrusion that contacts the plate-like terminal.   9. The gas sensor according to claim 2, wherein the pair of output extraction terminals facing each other and the pair of energization terminals facing each other are placed in a substantially orthogonal direction in the insulator. An ion-conducting solid electrolyte material is formed in a cylindrical shape with a closed end, a reference electrode layer in contact with the reference gas is formed on the inside, and a measurement electrode layer in contact with the measurement gas is formed on the outside. In a method for manufacturing a cup-type gas sensor having a concentration detection element for detecting the concentration of a specific gas component of
A reference electrode fitting having a reference electrode output terminal and a reference electrode connection portion is inserted into the concentration detection element, a measurement electrode fitting having a measurement electrode output terminal and a measurement electrode connection portion is fitted to the measurement electrode, The concentration detection element is inserted and fixed in a substantially cylindrical housing through a fixing member, and includes at least a pair of output terminals of the reference electrode terminal and the measurement electrode terminal and the housing, and the pair of output terminals Forming a detection unit that is exposed above the housing; and
A pair of output extraction terminals are attached to the insulator, a pair of signal lines are connected to the pair of output terminals, the pair of signal lines are inserted into a sealing member provided with a plurality of insertion holes, and these are substantially cylindrical. In the casing of the
An output extraction unit forming step of forming an output extraction unit comprising at least the signal line, the output extraction terminal, the insulator, the casing, and the sealing member;
Either one of the output terminal and the output extraction terminal is formed into a spring shape having a substantially U shape using an elastic metal material, and the other is formed into a plate shape, and a terminal fitting forming step of forming the other into a plate shape,
Gas sensor assembly process for completing the gas sensor by inserting the detection unit into the output extraction unit and at the same time elastically conducting the output terminal and the output extraction terminal in the output terminal insertion hole provided in the insulator And a method for manufacturing a gas sensor.