JP2010223750A - Gas sensor and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas sensor having improved durability to external vibration, and to provide a method of manufacturing the same. <P>SOLUTION: The gas sensor includes a detection section 20 and an output section 10. In this case, the detection section 20 includes a gas sensor element 21 and a housing 22 for disposing and fixing the gas sensor element 21 in gas to be measured. Then, the output section 10 at least includes: a signal line 101 for taking out the output of the gas sensor element 21 for transmitting to the outside; a nearly cylindrical casing 12 for covering the periphery of the signal line 101; and an insulator 14 that fixes the signal line 101 to a prescribed position in the casing 21 and insulates the signal line 101 from the casing 12. Further, the gas sensor includes a connection fixture 11 for connecting a detection electrode layer 216 disposed in the detection section 20 and a conductor 102 of the signal line 101 disposed in the output section 10, and a first contacting section 114 and a second contacting section are provided in the connection fixture 11 as a restriction means capable of resiliently deforming the insulator 14 and the connection fixture 11 in axial and radial directions of the gas sensor 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to the structure of a gas sensor that detects the concentration of a specific gas component contained in combustion exhaust discharged from an internal combustion engine, and more particularly to a gas sensor that is used in an environment in which vibrations received from outside such as a motorcycle are large. Is preferred.

  Conventionally, a gas sensor for detecting the concentration of a specific gas component such as oxygen contained in combustion exhaust gas has been provided in a combustion exhaust passage of an internal combustion engine such as an automobile engine, and the air-fuel ratio is determined by the detected concentration of the specific gas component. Control and temperature control of exhaust treatment catalyst are performed.

  As such a gas sensor, an oxygen concentration detection element is provided in which a measurement electrode layer in contact with a gas to be measured and a reference electrode layer in contact with the atmosphere introduced as a reference gas are provided on the surface of an oxygen ion conductive solid electrolyte such as zirconia. In addition, an oxygen sensor or the like that measures the oxygen concentration in the measurement gas by detecting a potential difference generated between both electrodes by the difference between the oxygen concentration in the measurement gas and the oxygen concentration in the reference gas is widely used. (For example, refer to Patent Document 1, Patent Document 2, etc.).

  In recent years, from the viewpoints of environmental protection, fuel consumption reduction, and the like, combustion control using such a gas sensor has been achieved even in a motorcycle (see, for example, Patent Document 3).

  However, in the case of a motorcycle, the space for mounting the gas sensor is limited compared to an automobile or the like, the vibration received from the outside is large, and the base end of the gas sensor is exposed to the outside. For this reason, it is used in a harsh environment that is easily contaminated by mud splashing or water. In addition, in the recent intense cost reduction competition, there is an increasing demand for further reduction in manufacturing cost even in the manufacture of such a gas sensor.

  Therefore, in view of such circumstances, the present invention provides a gas sensor that is excellent in durability and particularly suitable for being mounted on a combustion exhaust passage of a motorcycle, and a manufacturing method for easily manufacturing such a novel gas sensor. The purpose is to provide.

  In the first invention, a gas sensor comprising a reference electrode layer facing a reference gas on one surface of a solid electrolyte body formed in a substantially bottomed cylindrical shape, and a measurement electrode layer facing a gas to be measured on the other surface A housing for disposing / fixing at least the gas sensor element and the gas sensor element in a measured gas in a gas sensor for detecting a specific component in the measured gas by arranging a part of the element in the measured gas flow path And at least a signal line that takes out the output of the gas sensor element and transmits it to the outside, a substantially cylindrical casing that covers the outer periphery of the signal line, and the signal line are fixed at a predetermined position in the casing. And an output portion including an insulator that insulates the signal line from the casing, and the detection electrode layer disposed in the detection portion and the output portion are disposed in the output portion. And a connecting member for connecting the signal line, and a restraining means capable of elastically deforming the insulator and the connecting member in an axial direction and a radial direction of the gas sensor. Item 1).

  Specifically, in the second invention, the connection fitting is formed using a metal material having electrical conductivity and elasticity, and the inner wall of the solid electrolyte substrate is elastically pressed to form the reference electrode layer. At least two or more contact portions that conduct, and as the restraining means, the first contact portion presses the inner wall of the base-end-side opening of the solid electrolyte body in the outer direction, and the second contact portion The portion is in contact with a diameter-changing portion that decreases in diameter toward the tip provided in the solid electrolyte body, and elastically presses the outer diameter direction and the axial direction of the diameter-changing portion. (Claim 2).

  In the third invention, as the restraining means, an elastic member formed in a substantially cylindrical shape covering at least a part of the side surface of the insulator is inserted between the insulator and the casing, and the side surface of the casing is Clamping together with the elastic member from the outside to the inside, the insulator and the casing are formed in a stepped cylindrical shape, and a large diameter portion having a large diameter is formed in the casing. The side surface and an elastic metal member are sandwiched between elastic fixing members formed in a substantially annular shape (claim 3).

  According to a fourth aspect of the present invention, there is provided a gas sensor manufacturing method for detecting a specific gas component in a gas to be measured. The solid electrolyte material having specific ion conductivity is formed into a substantially bottomed cylindrical shape having one end opened and the other closed. Forming a gas sensor element by forming a measurement electrode layer and a reference electrode layer made of a porous metal film on opposite surfaces of the gas sensor element, and arranging and fixing the gas sensor element and a part thereof in a gas to be measured; A detecting portion forming step for forming a detecting portion by means of the above, a signal line, an elastically deformable first abutting portion having a diameter slightly larger than a base end side opening diameter of the gas sensor element, and the opening diameter A second abutting portion having a smaller diameter and elastically deformable, and fixing the metal fitting connected to the signal line within the casing via an insulator to form an output portion Output part forming step and the above connection money The characterized by comprising the step with a gas sensor assembly for forming the gas sensor assembly and the detector unit and the output unit is inserted into the solid electrolyte body (Claim 4).

  According to the first invention, since the insulator and the connection fitting are fixed by the elastically acting restraining force acting in both the axial direction and the radial direction of the gas sensor, vibration from the outside is transmitted. In this case, the restraining means can be elastically deformed in both the axial direction and the radial direction to absorb vibrations. Therefore, even in a gas sensor that detects the concentration of a specific gas component in the combustion exhaust gas of a combustion engine with large vibration from the outside such as a motorcycle and performs combustion control and exhaust purification control, the reference electrode layer and the above-described Contact failure with the connection fitting is less likely to occur, and reliability is improved.

  According to the second aspect of the invention, the first contact portion and the second contact portion are elastically deformed with respect to radial vibration, and the radial vibration is absorbed. In contrast, the second contact portion is in contact with the diameter-changing portion whose diameter decreases toward the tip, so that it is elastically pressed not only in the radial direction but also in the axial direction. When there is a vibration, the second contact portion is elastically deformed and the vibration is absorbed. Therefore, since at least one of the first contact portion and the second contact portion is kept in contact with the reference electrode layer, the reliability of the gas sensor used in an environment where vibration is intense from the outside. Can be further improved.

  According to the third invention, since the elastic member is elastically deformed with respect to the radial vibration, the radial vibration is absorbed, and the insulator can be held in a stable position in the casing. Since the fixing member is elastically deformed with respect to the axial vibration, the vibration in the cram school direction is absorbed. Therefore, vibration from the outside is not easily transmitted to the connection fitting via the insulator, so that contact failure between the reference electrode layer and the connection fitting is further suppressed, and a highly reliable gas sensor can be realized.

  According to the fourth aspect of the invention, when the detection portion and the output are assembled, the second abutment portion functions as a guide when inserted into the gas sensor element, so that the assembly operation is facilitated. In addition, since the second contact portion is inserted into the gas sensor element while being elastically deformed, damage to the gas sensor element can be avoided during assembly. Therefore, it becomes easy to manufacture a gas sensor with high reliability against external vibration, and the manufacturing cost can be reduced.

Sectional drawing showing the outline | summary of the gas sensor in the 1st Embodiment of this invention. (A) is a perspective view of the connection metal fitting which is the principal part in the 1st Embodiment of this invention, (b) principal part sectional drawing explaining the effect of this invention. The front view and cross-sectional view which show the modification of the connection metal fitting used for the gas sensor in the 1st embodiment of the present invention to (a) to (d). In the gas sensor manufacturing method of the present invention, the outline of the assembly method of the output unit is shown, (a) is a sectional view showing the assembly procedure of the output unit, (b) is a cross-sectional view of the main part during the assembly of the output unit FIG. 4C is a cross-sectional view of the output unit in the assembled state. The manufacturing method of the gas sensor of this invention WHEREIN: The outline | summary of the assembly method of a detection part is shown, (a) is sectional drawing which shows the assembly procedure of a detection part, (b) is sectional drawing in the assembly state of a detection part. Sectional drawing which shows the outline | summary of the assembly method of an output part and a detection part in the manufacturing method of the gas sensor in 1st Embodiment in this invention.

  The present invention is, for example, a heaterless that is mounted in a combustion exhaust passage of an internal combustion engine such as a motorcycle engine at a position close to an exhaust pipe of the internal combustion engine and activates a gas sensor element using a high temperature of the combustion exhaust. This type of gas sensor detects the concentration of specific gas components such as oxygen and hydrogen present in the combustion exhaust gas, calculates the air-fuel ratio, NOx concentration, etc., and controls the combustion of the internal combustion engine, or the exhaust gas treatment device It is suitable for a gas sensor used for controlling the operation of the above. The gas sensor 1 according to the first embodiment of the present invention will be described by taking as an example an oxygen sensor that detects an oxygen concentration as a specific gas component in the gas to be measured.

FIG. 1 is a cross-sectional view showing the entire gas sensor 1 according to the first embodiment of the present invention. In the following description, the upper side of the figure is referred to as the proximal end side, and the lower side is referred to as the distal end side or the flow path side. As shown in FIG. 1, the gas sensor 1 is mounted on a flow path wall 30 of a measured gas flow path 300 through which a measured gas flows, and a distal end side is exposed in the measured gas flow path 300 and is externally exposed on a proximal end side. It is connected to an unillustrated electronic control device.
The gas sensor 1 detects the potential difference generated by the oxygen concentration gradient between the atmosphere introduced inside the gas sensor element 10 and the gas to be measured flowing outside, and outputs the detected potential difference as an output signal. It is comprised by the output part 10 transmitted to the control apparatus of the omission of illustration provided.

The output unit 10, which is the main part of the present invention, absorbs external vibration and is less likely to cause an output abnormality due to poor contact in order to stably extract output from the detection unit 10 described later.
The output unit 10 includes a connection fitting 11 connected to a reference electrode layer 216 of a gas sensor element 21 to be described later, a signal line 101 that is connected to the connection fitting 11 and transmits a signal to an electronic control device provided outside, and a connection fitting. 11 and a casing 12 that covers and protects the periphery of the signal line 101 while holding it at a predetermined position with the tip of the signal line 101, an insulator 14 that secures insulation between the connection fitting 11 and the casing 12, and the signal line 101 in the casing 12. A sealing member 130 that seals the base end side of the casing 12, a water repellent filter 131 that prevents the intrusion of water droplets while introducing air from the air introduction hole 122 provided in the casing 12, and an insulator. 14 and the casing 12, an elastic member 132 that suppresses vibration of the insulator 14, and the insulator 14 are cased. It is constituted by an insulator holding metal fitting 133 for elastically fixed grayed within 12.

  The connection fitting 11 is formed using a conductive and elastic metal material such as stainless steel or Ni-based alloy (for example, Inconel (trademark)), and is fitted to the insulating coating portion of the signal line 101. A cylindrical fixing portion 111, a crimping portion 112 for conducting the core wire 102 of the signal line 101 and the connection fitting 11, a flange portion 113 protruding in the radial direction and contacting the lower end surface of the insulator 14, and a solid electrolyte substrate The first abutting portion 114 that elastically contacts the inner peripheral surface 212 of the base end portion 211 of the 21 to conduct the reference electrode layer 216 and the connection fitting 11, and the diameter changing portion 213 of the solid electrolyte base 21 A second contact portion 116 that elastically abuts to establish conduction between the reference electrode layer 216 and the connection fitting 11 is provided.

  The casing 12 is made of a metal material such as stainless steel. A small diameter portion 121 having a small diameter is formed on the proximal end side, and a large diameter portion 126 having a large diameter is formed on the distal end side, and the small diameter portion 121 and the large diameter are formed. An intermediate diameter portion 124 that is slightly larger in diameter than the small diameter portion 121 is formed between the small diameter portion 121 and the diameter changing portion 123 that is expanded from the small diameter portion 121 to the intermediate diameter portion 124. It is formed in a stepped cylindrical shape in which a diameter changing portion 125 that is expanded to the large diameter portion 126 is formed. A plurality of air introduction holes 122 are formed in the side surface of the small diameter portion 121. The opening of the small diameter portion 121 provided on the base end side of the casing 12 is sealed while maintaining the water tightness while inserting and holding the signal line 101 by the sealing member 130 made of an elastic member such as heat resistant rubber. Yes. An insulator 14 made of an insulating material is stored and held in the center of the casing 12. The front end side of the casing 12 is inserted into a boss portion 221 of the housing 22 which will be described later, and is fixed at the fixing portion 127 by fixing means such as press-fitting and caulking welding.

The insulator 14 is made of an insulating material such as high-purity alumina, and an insulator small-diameter portion 141 having a small diameter is formed on the base end side, and an insulator large-diameter portion 142 having the largest diameter is formed on the middle. An insulator medium diameter portion 143 having a slightly smaller diameter is formed on the distal end side, and is formed in a stepped cylinder shape with shaft holes 144 and 145 into which the signal line 101 is inserted at the center.
The insulator 14 achieves electrical insulation between the signal line 101 and the casing 12, and holds the signal line 101 at a predetermined position in the casing 12.
A substantially cylindrical water-repellent filter 131 is inserted into the insulator small-diameter portion 141, and a cylindrical elastic member 132 made of heat-resistant rubber or the like is further interposed between the water-repellent filter 131 and the casing small-diameter portion 121. By inserting and caulking the casing small-diameter portion 121, the insulator small-diameter portion 141 is elastically held and fixed while maintaining watertightness with the casing small-diameter portion 121, and vibration in the radial direction is suppressed.
The large-diameter portion 142 of the insulator 14 is elastically sandwiched between the substantially annular holding metal 133 and the diameter changing portion 125 of the casing 12 to suppress axial vibration.
Note that the insulator medium diameter portion 143 and the shaft hole small diameter portion 144 are not essential, and they are eliminated for cost reduction, and a simpler shape including the insulator small diameter portion 141, the insulator large diameter portion 142, and the shaft hole 145 is provided. You may form in the stepped cylinder shape.
The insulator intermediate diameter portion 143 is provided for the purpose of positioning the holding metal 133 during assembly, but the insulator 14 can be assembled in the casing 12 even if it is eliminated.
Further, the shaft hole small diameter portion 144 is intended to prevent the connection fitting 11 from coming off, but when the shaft hole small diameter portion 144 is eliminated, the collar portion 113 provides a function of preventing the removal.

The detection unit 20 includes a gas sensor element 21, a housing 22 that holds and fixes the gas sensor element 21 inside thereof, and a cover body 23 that is provided on the distal end side of the housing 22 and protects a portion of the gas sensor element 21 that is exposed to the gas to be measured. It is configured.
The gas sensor element 21 includes, for example, a solid electrolyte base 210 formed in a bottomed cylindrical shape having a base end side opened and a tip end side closed using an oxygen ion conductive solid electrolyte material such as zirconia. The porous reference electrode layer 216 made of platinum or a platinum alloy and the measurement electrode layer 217 are formed on the inner peripheral surface and the outer peripheral surface. The inside of the solid electrolyte substrate 210 is a reference gas introduction chamber 214, and a substrate locking portion 215 whose diameter is increased toward the outside is formed in the middle of the solid electrolyte substrate 210.
The inner diameter of the base end side opening 211 of the solid electrolyte substrate 210 is formed larger than the inner diameter of the reference gas chamber 214, and the inner wall of the solid electrolyte gas 210 is between the base end side opening 211 and the reference gas chamber 214. A diameter changing portion 213 having a diameter reduced toward the distal end side is formed.

The gas sensor element 21 is inserted into a housing 22 formed in a substantially cylindrical shape from a heat-resistant metal material such as stainless steel, and the base locking portion 214 is locked to a housing locking portion 225 whose inside is reduced in diameter. The housing caulking portions 226 and 227 are swaged and fixed via a metal seal member 240, an insulating powder seal member 241, an insulating holding member 242, a metal sealing member 243, and the like. The measurement electrode layer 217 is electrically connected to the housing 22 via the metal seal member 240.
A screw portion 224 is formed on the outer periphery of the housing 22 and is screwed to the measured gas flow channel wall surface 30 via a gas socket 244 so that the tip of the gas sensor element 21 is exposed to the measured gas flow channel 300. keeping. The measurement electrode layer 217 is in a grounded state with the measured gas flow passage wall surface 30 as the ground via the housing 22.
A boss portion 221 is formed on the proximal end side of the housing 22, and a large diameter portion 126 provided on the distal end side of the casing 12 is inserted into the boss portion 221 and fixed by laser welding 127 or the like.
Further, the portion of the gas sensor element 21 exposed to the gas to be measured is covered with a substantially hat-shaped cover body 23 that protects the portion. A flange portion 231 is formed on the base end side of the cover body 23, and is fixed by caulking by a cover body caulking portion 228 provided at the distal end of the housing 22.
Openings 232 for introducing and extracting the gas to be measured into and from the cover body are appropriately formed in the side surface and the bottom surface of the cover body 23.

With reference to FIG. 2, the connection fitting 11 that is a main part of the present invention will be described in detail, and the effects of the present invention will be described.
2A is a perspective view of the connection fitting 11 in a state where it is crimped to the signal line 101, and FIG. 2B is an enlarged cross-sectional view of a main part shown for explaining the effect of the present invention.
The fixing portion 111 is crimped so as to cover the insulating coating of the signal line 111 and fixes the connection fitting 11 to the signal line 101.
The crimping part 112 provided continuously to the fixing part 111 is formed in a substantially cylindrical shape, and is crimped in a state where the core wire 102 of the signal line 101 is inserted inside, so that the signal line 101 and the connection fitting 11 are electrically connected. ing.
Furthermore, the first contact portion 114 formed continuously with the distal end side of the crimping portion 112 is formed in a substantially cylindrical shape with a diameter (φD ₁ ) slightly larger than the inner diameter of the base end portion 211 of the solid electrolyte substrate 21. In addition, a part of the side surface is notched in the axial direction and has a substantially C-shaped cross section.
A flange portion 113 projecting in the radial direction is formed on the proximal end side of the first contact portion 114, and the inclined portion 115 is formed such that the distal end side of the first contact portion 114 is tapered toward the distal end side. Is formed.
Further, the second contact portion 116 formed continuously with the first contact portion 114 is divided into two forks, and is formed in a substantially tongue-like shape in which the side edge 117 is tapered toward the tip. its outer diameter is formed to a smaller diameter than the opening diameter of the tip portion 211 of the solid electrolyte base 21 (φD _2).

As shown in FIG. 2 (b), the first contact portion 114 is inserted while being reduced in diameter with respect to the opening of the base end portion 211 of the solid electrolyte base 21, so that the inside of the solid electrolyte base 21 is inside. in inserted state the first contact portion 114 and the inner circumferential surface 212 elastically pressed against the outer diameter direction (see the diagram P _2).
Further, the second contact portion 116 elastically presses the diameter changing portion 213 formed inside the solid electrolyte substrate 21 not only in the outer diameter direction but also in the axial direction (this figure P). ₁ ).
For this reason, since the electrical connection with the reference electrode layer 216 formed on the surface of the inner peripheral surface 212 is ensured at two locations of the first contact portion 114 and the second contact portion 116, vibration from the outside As a result, poor contact between the reference electrode layer 216 and the connection fitting 11 is less likely to occur.
Further, the upper surface and the lower surface of the large-diameter portion 142 of the insulator 14 are in contact with the diameter changing portion 125 and the fixing metal 133, respectively, and the flange 113 of the connection metal 11 and the lower end surface of the insulator 14 are in contact with each other. Therefore, the vibration of the insulator 14 in the axial direction is suppressed (see P ₃ , P ₄ , and P _{5 in} this figure).
Further, the small diameter portion 141 of the insulator 14, the vibration in the radial direction is absorbed by the elastic member 124 (see the diagram _{P 6).}

3A to 3D show connection fittings 11a, 11b, and 11c as modifications of the connection fitting 11. FIG.
As shown in the figure (a), in the connection fitting 11a, the outer diameter (φD2a) of the second contact portion 116a is smaller than the maximum inner diameter of the diameter changing portion 213 of the solid electrolyte substrate 21, and the minimum inner diameter is slightly larger. A part thereof is cut out to form a cylindrical shape having a substantially C-shaped cross section. By adopting such a shape, in addition to the same effects as those of the above-described embodiment, the second contact portion 116a of the connection fitting 11 can be easily inserted into the diameter changing portion 213 during assembly.
Further, as shown in FIG. 5B, in the connection fitting 11b, a press-fit portion 118 that extends to the proximal end side of the flange portion 113b and is partially cut out and is substantially cylindrical and can be inserted into the distal end side opening of the insulator 14. Is formed. By adopting such a shape, in addition to the same effects as those of the above-described embodiment, the press-fit portion 118 is firmly fixed to the distal end side opening of the insulator 14. Therefore, the movement of 11b is further suppressed without being connected to the vibration in the axial direction, and poor contact between the reference electrode layer 216 and the connection fitting 11b can hardly occur.
Furthermore, as shown in the figure (c), the fittings 11c, may be formed by providing an inclination angle theta _T so that the tapered toward the side surface of the second contact portion 116c at the tip. By adopting such a shape, in addition to the same effects as in the above embodiment, the second contact portion 116c can be easily inserted into the diameter changing portion 213 during assembly, and the reference electrode layer 216 and the second contact portion 213 can be easily inserted. The contact area along the contact portion 116c increases, and contact failure can hardly occur.
Further, as shown in FIG. 4D, in the connection fitting 11d, a part of the side surface of the first contact portion 114d and the second contact portion 116d is cut out in a tongue shape and protruded in the outer peripheral direction. The tongue-like contact portions 119a and 119b may be provided. By adopting such a shape, in addition to the same effects as in the above embodiment, the tongue-like contact portions 119a and 119b press the reference electrode layer 216 in the outer diameter direction, so that contact failure can be further prevented.
In the connection fittings 11, 11 a, 11 b, 11 c, and 11 d, the crimping portion 112 is formed so as to be thin in a slanted manner toward the end portion, or in order to make contact conduction with the core wire 102 more reliable. It may be formed in a tooth shape or provided with serrations.

  Here, the outline of the method for manufacturing the gas sensor according to the first embodiment of the present invention will be described. As shown in FIG. 4A, the signal line 101 inserted into the sealing member 130 is pulled out to the front end side, and the casing 12, the elastic member 132, the water repellent filter 131, the insulator 14, the fixing metal 133, and the connection metal 11 are arranged in this order. Next, as shown in this figure (b), the insulator 14, the water repellent filter 131, and the elastic member 132 are held in a predetermined position in the casing 12 via the insulator 14 by the fixing bracket 133, The signal line 101 and the core wire 102 are caulked and fixed by the fixing part 111 and the crimping part 112, respectively, and pulled back to the base end side, so that the signal line connected to the connection fitting 11 as shown in FIG. 101 is held in the casing 12 with the insulator 14, the water repellent filter 131, the elastic member 132, and the sealing member 130 interposed therebetween. Shureta 14 by a fixing bracket 133 in a state of being disposed in a predetermined position inside the casing 12.

As shown in FIG. 5A, the cover body 23 is assembled from the front end side of the housing 22 and the 228 is caulked to form the reference electrode layer 216 and the measurement electrode layer 217 on the inner peripheral surface and the outer peripheral surface, respectively. The electrolyte base 21 is inserted into the housing 22 in a state where the seal member 240 is disposed on the housing locking portion 225, and the insulating powder seal member 241, the insulating holding member 242 and the like are sequentially arranged on the base end side of the solid electrolyte base 21. The insulating sealing member 242 is pressed to increase the density of the insulating powder seal member 241, and then the metal sealing member 243 is disposed. Next, as shown in FIG. 4B, the solid electrolyte body 21 is disposed in the housing 22, and the tip of the solid electrolyte body 21 is covered with the cover body 23.
The insulating powder seal member is molded and inserted in advance into a substantially cylindrical shape in order to improve the assembly workability, and is pressed in the axial direction so as to be uniform with respect to the circumferential direction via the insulating holding member 242. Adding confidentiality improves confidentiality.

As shown in FIG. 6, by crimping predetermined positions 121 and 124 of the casing 12, the insulator 14 is firmly fixed in the casing 12, and the base end portion of the casing 12 is moved by the sealing member 130. The sealed output section 10 is completed in a state where watertightness is ensured, and the solid electrolyte body 21 is fixed at a predetermined position of the housing 22 by caulking the predetermined position 227 of the housing 22 to complete the detection section 20. Then, when the output unit 10 and the detection unit 20 are assembled and the boss 221 of the housing 22 and the large-diameter portion 126 of the casing 12 are welded and fixed by laser welding or the like, the gas sensor 1 of the present invention is completed. At this time, since the flange 113 of the connection fitting 11 is in contact with the lower end surface of the insulator 14, the second contact portion provided on the distal end side of the connection fitting 11 in the solid electrolyte body 21 while being pushed in by the insulator 14. 116 are inserted in order. The second contact portion 116, so provided with a small diameter [phi] D ₂ than the opening diameter of the proximal opening 211 of the solid electrolyte body 21 is easy to insert, serves insertion guide. Further, when the second abutting portion 116 comes into contact with the diameter changing portion 213, the second abutting portion 116 is elastically pressed and is inserted while being easily reduced in diameter. Improves.
In addition, since the inclined surface 115 is formed on the distal end side of the first contact portion 114, the first contact portion 114 is inserted into the opening of the solid electrolyte body 21 while being easily reduced in diameter. The contact portion 114 presses the proximal end inner peripheral wall 212 of the solid electrolyte body 21 in the outer diameter direction.
As a more specific assembling procedure, for example, the housing 22 and the cover body 23 are crimped in advance, and then the sealing member 240, the solid electrolyte base 21, the insulating powder sealing member 241, the insulating holding member 242 and the like. Are arranged in order and temporarily assembled, the insulating holding member 242 is pressed to increase the packing density of the insulating powder seal member 241, then the metal sealing member 243 is temporarily assembled, and current is applied while pressing the caulking portion 227. In addition, by generating a Joule heat and energizing a large current while applying an axial load, the desired part is heated by the Joule heat, and the material is temporarily softened and buckled. The caulking portion 226 is axially moved by the heat caulking that expresses the caulking force and can hold the solid electrolyte body 21 in the housing 22 in a stable state. Compressed to fixed.
The caulking portion 226 is formed thin so as to generate heat and buckle in the axial direction by heat caulking.

DESCRIPTION OF SYMBOLS 1 Gas sensor 10 Output part 101 Signal line 102 Core wire 11 Connection metal fitting 111 Fixing part 112 Crimp part 113 Collar part 114 First contact part 116 Second contact part 12 Casing 130 Sealing member 131 Water-repellent filter 132 Elastic member 133 Fixed member 14 Insulator 141 Insulator small diameter part 142 Insulator large diameter part 143 Insulator medium diameter part 20 Detection part 21 Solid electrolyte body 210 Solid electrolyte layer 214 Reference gas chamber 216 Reference electrode layer 217 Measurement electrode layer 22 Housing 23 Cover body 30 Measured Gas channel wall 300 Gas channel to be measured

JP 2000-193631 A JP 2007-278806 A JP 2008-280995 A

Claims (4)

  A part of a gas sensor element having a reference electrode layer facing a reference gas on one surface of a solid electrolyte body formed in a substantially bottomed cylindrical shape and a measurement electrode layer facing a gas to be measured on the other surface is covered. In a gas sensor that is disposed in a measurement gas flow path and detects a specific component in a gas to be measured, a detection unit including at least the gas sensor element and a housing that arranges and fixes the gas sensor element in the gas to be measured; And at least a signal line for taking out the output of the gas sensor element and transmitting it to the outside, a substantially cylindrical casing covering the outer periphery of the signal line, and fixing the signal line at a predetermined position in the casing, and the signal line and the above An output portion including an insulator for insulation from the casing, and the detection electrode layer disposed in the detection portion and the signal line disposed in the output portion are in contact with each other. Together comprise a fitting, characterized in that the said insulator and the fitting provided with elastically deformable restraining means axially and radially of the gas sensor gas sensor for.   The connection fitting is formed using a metal material having electrical conductivity and elasticity, and includes at least two or more contact portions that elastically press the inner wall of the solid electrolyte base and are electrically connected to the reference electrode layer. As the restraining means, the first abutting portion presses the inner wall of the proximal end side opening of the solid electrolyte body in the outer direction, and the second abutting portion is a tip provided on the solid electrolyte body. 2. The gas sensor according to claim 1, wherein the gas sensor comes into contact with a diameter-changing portion that decreases in diameter toward the surface and elastically presses the outer diameter direction and the axial direction of the diameter-changing portion.   As the restraining means, an elastic member formed in a substantially cylindrical shape covering at least a part of the side surface of the insulator is inserted between the insulator and the casing, and the side surface of the casing is moved from the outside toward the inside. The insulator and the casing are formed into a stepped cylindrical shape together with the members, and a metal material having elasticity and an inner side surface of the diameter-changing portion in which the large diameter portion of the insulator is formed in the casing is formed. The gas sensor according to claim 1, wherein the gas sensor is sandwiched by an elastic fixing member formed in a substantially annular shape. In a gas sensor manufacturing method for detecting a specific gas component in a gas to be measured, a solid electrolyte material having specific ion conductivity is formed in a substantially bottomed cylindrical shape having one end opened and the other end closed, and faces each other. A measurement electrode layer made of a porous metal film and a reference electrode layer are formed on the surface to form a gas sensor element, and a detection portion is formed by the gas sensor element and a housing in which a part of the gas sensor element is disposed and fixed in the gas to be measured. A detection part forming step;
A signal line, a first abutting portion having a diameter slightly larger than the opening diameter on the base end side of the gas sensor element and elastically deformable, and a diameter smaller than the opening diameter and elastically deformable An output portion forming step of forming an output portion by fixing the metal fitting connected to the signal line in the casing via an insulator;
A gas sensor manufacturing method comprising: a gas sensor assembly step of inserting the connection fitting into the solid electrolyte body and assembling the detection unit and the output unit to form the gas sensor.

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