JP2008170341A - Gas sensor element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To incorporate assembling parts same in shape on the surface and back sides of them even if the distance between through holes is made to be large. <P>SOLUTION: The drawing is a plan view of the protective layer 7 arranged on the surface of an NOx sensor element and the second alumina layer 102 of the heater part arranged on the back side of the NOx sensor element. Electrode pads 121, 122 and 123, which are formed into a rectangular shape, extending in the longitudinal direction NT of the NOx sensor element are arranged to the protective layer 7 and electrode pads 124, 125 and 126 are arranged on the second alumina layer 102. The electrode pads 121, 122 and 123 respectively have the parts opposed to the electrode pads 126, 125 and 124 (refer to NH1 and NH2 in a longitudinal range). Further, the through holes 115 and 116 in the electrode pads 125 and 126 for supplying a current to the heater part are arranged on the leading end sides (left-hand sides of the drawing) of the electrode pads 125 and 126 and the through hole 114 corresponding to the electrode pad 124 for outputting an NOx concentration detection signal is arranged on the rear end side (right-hand side of the drawing) of the electrode pad 124. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gas sensor element that detects the concentration of a specific gas component in a measurement target gas.

  2. Description of the Related Art Conventionally, a gas sensor element that is attached to an internal combustion engine such as an automobile engine and detects the concentration of a specific gas component in a measurement target gas such as exhaust gas has been developed. Some of such gas sensor elements are configured by laminating a plurality of members (solid electrolyte bodies, insulating members, etc.) formed in a plate shape extending in the longitudinal direction, and oxygen ions in the solid electrolyte body By detecting the electromotive force generated by the passage of the gas, the concentration of the specific gas component is detected. Such a gas sensor element includes a heater element that heats the gas sensor element to an activation temperature at which a signal corresponding to the concentration of a specific gas component (hereinafter referred to as a concentration detection signal) can be output (for example, Patent Documents). 1).

Further, in order to output signals from the electrodes arranged on the front surface side and the back surface side of the plurality of members to the outside of the gas sensor element, or to apply a voltage to the heating resistor and the electrode inside the heater element, A through hole penetrating the plurality of members is formed. Furthermore, electrode pads that are electrically connected to the heater element and the electrode member through conduction paths formed in the through holes are provided on the front side and the back side of the gas sensor element.
JP 2001-242129 A (FIG. 3)

  Incidentally, it is necessary to apply a high voltage to the heating resistor, whereas the current value of the concentration detection signal is very small. Therefore, in order to prevent the characteristics of the concentration detection signal from being deteriorated due to the influence of a high voltage applied to the heating resistor, a through hole (called a heater through hole) for connecting the heating resistor and the electrode pad is used. It is necessary to make the distance between the through-hole connected to the electrode pad that outputs the concentration detection signal (hereinafter referred to as a concentration detection through-hole) as large as possible.

  Further, the solid electrolyte body has conductivity. For this reason, when a plurality of through holes are formed in one solid electrolyte body, it is necessary to prevent current leakage between conduction paths provided in the plurality of through holes. Therefore, the distance between the plurality of through holes must be made as large as possible.

  Furthermore, in order to connect the gas sensor element to an external device, it is necessary to assemble an assembly part such as an electrode fitting that is in conductive contact with the electrode pad on the front side and the back side of the gas sensor element. If the arrangement of the electrode pads is the same on the front surface side and the back surface side of the gas sensor element, assembly parts having the same shape can be assembled on the front surface side and the back surface side of the gas sensor element. It is also desirable from the viewpoint of sharing the viewpoint and parts.

  However, when the distance between the through holes is increased in order to prevent the leakage current and the like, it is necessary to change the arrangement of the electrode pads accordingly. For this reason, there is a problem that the arrangement of the electrode pads differs between the front surface side and the back surface side of the gas sensor element, and it becomes impossible to assemble assembly parts having the same shape on the front surface side and the back surface side.

  The present invention has been made in view of these problems, and provides a gas sensor element that enables assembly of assembly parts having the same shape on the front surface side and the back surface side even when the distance between through holes is increased. The purpose is to do.

  The gas sensor element according to claim 1, which has been made to achieve the above object, includes a plate-shaped first solid electrolyte body having oxygen ion conductivity and a pair of first electrodes disposed on the first solid electrolyte body. A plate-shaped second solid electrolyte body disposed opposite to the first solid electrolyte body and having oxygen ion conductivity, a pair of second electrodes disposed on the second solid electrolyte body, and a second solid A plate-shaped third solid electrolyte body having oxygen ion conductivity disposed on the opposite side of the first solid electrolyte body across the electrolyte body and disposed on the third solid electrolyte body The first measurement chamber is disposed between the pair of third electrodes, the first solid electrolyte body, and the second solid electrolyte body, and into which the measurement target gas is introduced from the outside. One electrode and one electrode of the pair of second electrodes are accommodated. The first measurement chamber formed in this manner and the second measurement chamber formed so as to accommodate one of the pair of third electrodes and into which the measurement target gas introduced into the first measurement chamber is introduced A gas sensor main body that detects the concentration of a specific gas component in the measurement target gas, a plate-shaped first insulating member that is disposed on one side in the opposing direction of the gas sensor main body, and has an insulating property, and a gas sensor A plate-like second insulating member having an insulating property, which is disposed on a surface opposite to the side on which the first insulating member is disposed in the main body and has a heating resistor embedded therein; The gas sensor elements are formed in a plate shape extending in the direction of 3 and are arranged on the surface of the first insulating member and three on the surface of the second insulating member, and are formed in a shape extending in the longitudinal direction of the gas sensor element. Each electrode pad and six electrode pads In order to connect the electrode pad and any one of the first electrode, the second electrode, and the third electrode, the electrode pad is provided with a through hole formed so as to penetrate in the opposing direction of the gas sensor element, and is disposed on the first insulating member. Each of the three electrode pads is arranged so that there is a portion overlapping with one of the three electrode pads arranged on the second insulating member when projected in the opposing direction of the gas sensor element. Among the pads, the first electrode pad that is electrically connected to the third electrode housed in the second measurement chamber through the through hole is formed by three electrode pads disposed on the same insulating member as the first electrode pad. Among the six electrode pads, the second electrode pad that is electrically connected to one end of the heating resistor through the through hole and the other end of the heating resistor is disposed on the most rear end side in the longitudinal direction. And The third electrode pad that is electrically connected through the through hole is disposed on the same insulating member, and the second electrode pad and the third electrode pad are disposed on the same insulating member as the second electrode pad and the third electrode pad. Among the three electrode pads, the two electrode pads are arranged on the front end side in the longitudinal direction, and the first through hole connected to the first electrode pad is the rear end in the longitudinal direction in the first electrode pad. The second through hole and the third through hole, which are disposed on the side and connected to the second electrode pad and the third electrode pad, are disposed on the distal end side in the longitudinal direction in the second electrode pad and the third electrode pad, respectively. It is characterized by that.

  In the gas sensor element configured as described above, the first electrode pad is electrically connected to the third electrode accommodated in the second measurement chamber. That is, the gas sensor element detects the concentration of the specific gas component in the measurement target gas based on the current output from the first electrode pad.

  The first electrode pad is arranged on the most rear end side among the three electrode pads arranged on the same insulating member as the first electrode pad. For this reason, the remaining two electrode pads arranged on the same insulating member as the first electrode pad are arranged on the tip side of the first electrode pad. Therefore, the first electrode pad and the remaining two electrode pads are compared to the case where the first electrode pad and the remaining two electrode pads are arranged so that the positions in the longitudinal direction of the gas sensor element are the same. The distance between can be increased. Therefore, the distance between the first through hole corresponding to the first electrode pad and the through hole corresponding to the remaining two electrode pads can be increased, and current leakage between the conduction paths can be prevented. .

  Further, the first through hole is disposed on the rear end side in the first electrode pad. For this reason, the distance between the through holes corresponding to the remaining two electrode pads can be further increased as compared with the case where the first through holes are arranged on the tip side in the first electrode pad.

  The second and third electrode pads that are electrically connected to the heating resistor are arranged on the distal end side among the three electrode pads arranged on the same insulating member as the second and third electrode pads. The For this reason, the remaining one electrode pad disposed on the same insulating member as the second and third electrode pads is disposed on the rear end side with respect to the second and third electrode pads. Therefore, the second and third electrode pads and the remaining one electrode pad can be compared with the second and third electrode pads as compared with the case where the gas sensor elements are arranged at the same position in the longitudinal direction. The distance between the remaining one electrode pad can be increased. Therefore, the distance between the second through hole corresponding to the second electrode pad and the third through hole corresponding to the third electrode pad and the through hole corresponding to the remaining one electrode pad can be increased. The current leakage between the conduction paths can be prevented.

  Further, the second through hole and the third through hole are disposed on the tip side in the second electrode pad and the third electrode pad, respectively. For this reason, the distance from the through hole corresponding to the remaining one electrode pad is larger than when the second and third through holes are arranged on the rear end side in the second and third electrode pads. can do.

Further, in the gas sensor element according to claim 1, the three electrode pads disposed on the first insulating member are projected to the opposing direction of the gas sensor element, respectively, and then the three electrodes disposed on the second insulating member. It is arranged so that there is a portion that overlaps one of the pads. Therefore, if the overlapping part is a part that makes an assembly part such as an electrode fitting conductively contact (hereinafter also referred to as a conductive contact part), the arrangement of the conductive contact part in the first insulating member and the conductive part in the second insulating member are used. The arrangement of the contact portions can be made the same. For this reason, assembly parts having the same shape can be assembled on the front surface side (that is, the first insulating member side) and the back surface side (that is, the second insulating member side) of the gas sensor element. According to the gas sensor element of item 1, even if the distance between the through holes is increased, assembly parts having the same shape can be assembled on the front surface side and the back surface side of the gas sensor element.

  Furthermore, a first electrode pad electrically connected to the third electrode for detecting the concentration of the specific gas component in the measurement target gas, and a second and third electrode pad electrically connected to the heating resistor The distance between them can also be increased. Therefore, the distance between the first through hole corresponding to the first electrode pad and the second and third through holes corresponding to the second and third electrode pads can also be increased and applied to the heating resistor. It is possible to prevent deterioration of the characteristics of the density detection signal due to the influence of the high voltage.

  In the gas sensor element according to claim 1, as described in claim 2, the first electrode pad, the second electrode pad, and the third electrode pad have overlapping positions in the longitudinal direction of the gas sensor element. It is good to arrange so that it may not become.

  According to the gas sensor element configured as described above, the first through-hole is more than the case where the first electrode pad, the second electrode pad, and the third electrode pad are arranged so that the positions in the longitudinal direction overlap each other. The distance between the second through hole and the third through hole can be further increased.

  By the way, in order to activate the gas sensor element at an early stage, the second insulating member may be disposed closer to the third solid electrolyte body than the first solid electrolyte body. That is, early activation of the gas sensor element is aimed at by heating the third solid electrolyte body and the third electrode for detecting the concentration of the specific gas component in the measurement target gas faster. At this time, even if the first, second, and third electrode pads are arranged on the surface of the second insulating member, the concentration is increased by the influence of the high voltage applied to the heating resistor by having the above configuration. It can prevent that the characteristic of a detection signal deteriorates.

  Furthermore, the 3rd electrode electrically connected with the 1st electrode pad is arrange | positioned at the 3rd solid electrolyte body. For this reason, the length of the first through hole can be made shorter than disposing the third electrode pad on the first insulating member. Moreover, the heating resistor electrically connected to the second electrode pad and the third electrode pad is embedded in the second insulating member. Therefore, the lengths of the second through hole and the third through hole can be made shorter than arranging the second electrode pad and the third electrode pad on the first insulating member.

  Further, in the gas sensor element according to any one of claims 1 to 3, as described in claim 4, the second electrode pad and the third electrode pad are located at positions in the longitudinal direction of the gas sensor element. The second electrode pad and the second electrode pad and the third electrode pad are disposed on the insulating member different from the insulating member on which the second electrode pad and the third electrode pad are disposed, and when projected in the facing direction of the gas sensor element. Regarding the two electrode pads arranged so as to overlap with the third electrode pad, the through holes connected to the two electrode pads are arranged so that the positions of the gas sensor elements in the longitudinal direction are different from each other. It is good to do so.

  According to the gas sensor element configured as described above, the two electrode pads arranged so that there is a portion overlapping the second electrode pad and the third electrode pad when projected in the opposing direction of the gas sensor element. The through-holes corresponding to the two electrode pads (hereinafter referred to as the fourth through-hole and the fifth through-hole) have the fourth through-hole and the fifth through-hole as compared with the case where the positions in the longitudinal direction are the same. The distance between the through holes can be increased.

  Furthermore, in the gas sensor element according to any one of claims 1 to 4, it is preferable that a through hole is not formed in the overlapping portion as described in claim 5. As described above, the conductive contact portion is brought into contact with the overlapping portion. However, if a through hole is formed in this part, the conductive contact portion may enter the hole (hole), and as a result. The electrode pad may be peeled off. Therefore, since the through hole is not formed in the overlapping portion, the electrode pad can be prevented from peeling off.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an internal configuration diagram of a sensor main body 3 of a NOx sensor element 1 according to an embodiment to which the present invention is applied.

  In the following description, the left side of the sensor body 3 shown in FIG. 1 will be described as the front end side, and the right side will be described as the rear end side. Further, FIG. 1 shows an internal configuration of the front end portion of the sensor main body 3.

  The NOx sensor element 1 is a gas sensor element that can be used for detecting NOx concentration in the exhaust gas of various combustion equipment such as an internal combustion engine and a boiler of an automobile, for example. A heater 5 for heating the main body 3 (not shown in FIG. 1; see FIG. 3) and a protective layer 7 for protecting the surface of the sensor main body 3 (not shown in FIG. 1, see FIG. 3). .

  As shown in FIG. 1, the sensor body 3 has a structure in which a first pump cell 11, an oxygen concentration detection cell 12, and a second pump cell 13 are stacked via insulating layers 14 and 15 mainly composed of alumina.

  Among these, the first pump cell 11 includes a plate-shaped first solid electrolyte layer 31 made of zirconia having oxygen ion conductivity, a first inner electrode 35 disposed so as to sandwich the first solid electrolyte layer 31, and a first The first porous electrode 21 including the outer electrode 37 is provided. The first inner electrode 35 and the first outer electrode 37 are made of platinum, a platinum alloy, cermet containing platinum and ceramics (for example, a solid electrolyte body), and the like. A protective layer 22 is formed.

  The second pump cell 13 includes a plate-shaped second solid electrolyte layer 41 made of zirconia having oxygen ion conductivity, and a first surface disposed on the surface of the second solid electrolyte layer 41 facing the insulating layer 15. 2 and the second porous electrode 25 composed of the second outer electrode 47 and the second outer electrode 47. The second inner electrode 45 and the second outer electrode 47 are made of platinum, platinum alloy, cermet containing platinum and ceramics (for example, a solid electrolyte body), or the like.

  Further, the oxygen concentration detection cell 12 includes a plate-shaped detection solid electrolyte layer 51 made of zirconia having oxygen ion conductivity, a detection electrode 55 and a reference electrode arranged so as to sandwich the detection solid electrolyte layer 51. And a porous detection electrode 23 composed of 57. The detection electrode 55 and the reference electrode 57 are formed of platinum, platinum alloy, cermet containing platinum and ceramics (for example, a solid electrolyte body), or the like.

  A first measurement chamber 59 into which a measurement target gas is introduced is formed inside the NOx sensor element 1. A measurement target gas is introduced into the first measurement chamber 59 from the outside through the first diffusion resistor 16 disposed between the first pump cell 11 and the oxygen concentration detection cell 12.

  The first diffusion resistor 16 is formed of a porous body, and is disposed in the introduction path 19 of the measurement target gas from the front end side opening to the first measurement chamber 59 in the sensor body 3 to perform the first measurement. The introduction amount (passage amount) of the measurement target gas per unit time into the chamber 59 is limited.

  The introduction path 19 is a region on the tip side (left side in the drawing) of the first measurement chamber 59 in the space surrounded by the first pump cell 11 and the oxygen concentration detection cell 12. Further, the first inner electrode 35 of the first pump cell 11 (specifically, the first inner electrode 35 covered with the protective layer 22) and the detection electrode 55 of the oxygen concentration detection cell 12 are provided in the first measurement chamber 59. It is arranged to face.

  A second diffusion resistor 17 made of a porous body is provided on the rear end side (right side in the drawing) of the first measurement chamber 59, and the second inner electrode 45 and the second diffusion resistor 17 are connected to each other. A second measurement chamber 61 is formed between them.

  Further, a reference oxygen chamber 18 is formed between the oxygen concentration detection cell 12 and the second pump cell 13 in the sensor body 3, and the oxygen concentration so as to face the reference oxygen chamber 18. A reference electrode 57 of the detection cell 12 and a second outer electrode 47 of the second pump cell 13 are arranged.

  The sensor main body 3 configured in this way can pump (pump out) oxygen existing in the first measurement chamber 59 by the first pump cell 11, and the oxygen concentration detection cell 12 can provide oxygen concentration. It is possible to measure the oxygen concentration difference between the reference oxygen chamber 18 and the first measurement chamber 59 controlled to be constant, that is, the oxygen concentration inside the first measurement chamber 59.

The sensor body 3 is driven by a separately provided drive circuit (not shown), and is heated to the activation temperature by the heater 5 (see FIG. 3).
The drive circuit drives and controls the heater unit 5 to heat the sensor body 3 to an activation temperature (for example, 750 ° C.). In this state, the voltage Vs across the oxygen concentration detection cell 12 is set in advance. The first pump current Ip1 flowing through the first pump cell 11 is controlled so as to be a constant voltage (for example, 425 mV). The drive circuit controls the first pump current Ip1 and applies a constant second pump voltage Vp2 (for example, 450 mV) to the second pump cell 13 in the direction in which oxygen is pumped from the second measurement chamber 61. The second pump current Ip2 flowing through the two pump cells 13 is detected.

  Since the specific component to be detected is NOx (nitrogen oxide), the oxygen concentration in the first measurement chamber 59 is maintained at a low oxygen concentration (≈0%), and the second pump voltage Vp2 is set to a predetermined voltage. When held, in the second measurement chamber 61, NOx is decomposed (reduced) by the catalytic action of the second porous electrode 25 constituting the second pump cell 13, and oxygen obtained by the decomposition is released from the second measurement chamber 61. The second pump current Ip2 flows by being extracted.

  That is, the second pump current Ip2 has a magnitude corresponding to the concentration of NOx contained in the measurement target gas, and the NOx sensor element 1 of the present embodiment detects the oxygen concentration generated by the reduction reaction of NOx. Thus, the NOx concentration is indirectly detected.

Next, a method for manufacturing the sensor body 3 will be described.
The manufacturing method of the sensor main body 3 includes a laminated body forming step, a cutting step, and a firing step. First, in the laminated body forming step, a NOx sensor laminated body that becomes the sensor body 3 after firing is formed, and in the next cutting step, the tip side (left side in FIG. 1) of the NOx sensor laminated body is cut. And in the baking process implemented after a cutting process, the sensor main-body part 3 is manufactured by baking the NOx sensor laminated body from which the front end side was cut | disconnected in a cutting process by high temperature processing.

  As described above, the sensor main body 3 obtained in this way is used to measure the gas to be measured introduced into the first measurement chamber 59 via the first diffusion resistor 16 in the first measurement chamber 59. After being controlled to be constant, it is introduced into the second measurement chamber 61 via the second diffusion resistor 17, and the oxygen concentration generated by the NOx reduction reaction is detected based on the second pump current Ip2, thereby indirectly. The NOx concentration is detected.

  Next, the configuration of the NOx sensor element 1 will be described. FIG. 2 is an exploded perspective view schematically showing the configuration of the NOx sensor element 1, and FIG. 3 is a plan view of the protective layer 7 and the second alumina layer 102 showing the arrangement of the electrode pads 121-126. In the following description, the left side of the NOx sensor element 1 shown in FIG. 2 will be described as the front end side, and the right side will be described as the rear end side.

As described above, the NOx sensor element 1 includes the sensor body 3, the heater 5, and the protective layer 7.
Among these, the sensor body 3 includes a first pump cell 11, an oxygen concentration detection cell 12, and a second pump cell 13 as shown in FIG. 2.

  The heater unit 5 is mainly composed of plate-shaped first alumina layer 101 and second alumina layer 102 made of an insulating material alumina, and Pt (platinum), and generates heat when current is applied. And a structure in which a heating resistor is sandwiched between the first alumina layer 101 and the second alumina layer 102. The heater unit 5 is disposed on the back surface side of the sensor main body unit 3, that is, on the side close to the second pump cell 13.

The protective layer 7 is formed in a plate shape with an insulating material alumina, and is disposed on the surface side of the sensor body 3, that is, on the side close to the first pump cell 11.
The NOx sensor element 1 includes through holes 111 and 112 that penetrate the protective layer 7, the first pump cell 11, and the oxygen concentration detection cell 12, a through hole 113 that penetrates the protective layer 7, the second pump cell 13, A through hole 114 that penetrates the first alumina layer 101 and the second alumina layer 102 and through holes 115 and 116 that penetrate the second alumina layer 102 are formed.

  Further, on the surface of the NOx sensor element 1, that is, on the surface of the protective layer 7 on the side not facing the first pump cell 11, a rectangular extending in the longitudinal direction NT of the NOx sensor element 1 as shown in FIG. Electrode pads 121, 122, 123 formed in a shape are arranged. Further, a rectangular shape extending in the longitudinal direction NT of the NOx sensor element 1 is formed on the back surface of the NOx sensor element 1, that is, on the surface of the second alumina layer 102 of the heater unit 5 that is not opposed to the second pump cell 13. The electrode pads 124, 125, 126 formed in the above are disposed.

  Of these, the electrode pad 121 is electrically connected to the reference electrode 57 via a conductor embedded in the through hole 111 (see the conduction path 131 in FIG. 2), and the voltage Vs is detected. it can.

  The electrode pad 122 is electrically connected to the first inner electrode 35, the detection electrode 55, and the second outer electrode 47 via a conductor embedded in the through hole 112 (the conduction path 132 in FIG. 2). ) And a ground voltage is applied.

  The electrode pad 123 is electrically connected to the first outer electrode 37 via a conductor embedded in the through hole 113 (see the conduction path 133 in FIG. 2), and the first pump current Ip1 is output. Is done.

  The electrode pad 124 is electrically connected to the second inner electrode 45 via a conductor embedded in the through hole 114 (see the conduction path 134 in FIG. 2), and the second pump current Ip2 is output. Is done.

  The electrode pad 125 is electrically connected to one end of the heating resistor in the heater section 5 via a conductor embedded in the through hole 115 (see the conduction path 135 in FIG. 2), and the heater is energized. A positive voltage is applied.

  The electrode pad 126 is electrically connected to the other end of the heating resistor in the heater section 5 via a conductor embedded in the through hole 116 (see the conduction path 136 in FIG. 2), and the heater A negative voltage for energization is applied.

  Furthermore, the electrode pad 121 is disposed so that the tip side is the front end from the longitudinal position NI1 and the longitudinal position NI2 is the rear end. The through hole 111 is disposed on the distal end side in the electrode pad 121 from the longitudinal position NI1. The longitudinal position NI1 is located on the distal end side with respect to the longitudinal position NI2.

  In addition, the electrode pad 122 is disposed such that the longitudinal position NI1 is the leading end, the rear end side is longer than the longitudinal position NI2, and the distal end position is longer than the longitudinal position NI3. The through hole 112 is disposed in the electrode pad 122 on the rear end side from the longitudinal position NI2. Note that the longitudinal position NI2 is located on the distal end side with respect to the longitudinal position NI3.

  In addition, the electrode pad 123 and the electrode pad 124 are disposed so that the longitudinal position NI3 is the leading end and the rear end side is longer than the longitudinal position NI4. The through hole 113 and the through hole 114 are disposed on the rear end side in the electrode pad 123 and on the electrode pad 124 from the longitudinal position NI4. The longitudinal position NI3 is located on the tip side from the longitudinal position NI4.

  In addition, the electrode pad 125 and the electrode pad 126 are arranged so that the front end side from the longitudinal position NI1 is the leading end and the longitudinal position NI2 is the trailing end. The through hole 115 and the through hole 116 are disposed on the tip side from the longitudinal position NI1 in the electrode pad 125 and the electrode pad 126, respectively.

  In the NOx sensor element 1 configured as described above, the electrode pad 124 to which the second pump current Ip2 is output has three electrode pads (that is, electrode pads 124, 125, 126) at the most rear end side. For this reason, the electrode pads (that is, the electrode pads 125 and 126) for energizing the heater unit 5 are arranged on the tip side of the electrode pads 124. That is, the electrode pad 124 and the electrode pads 125 and 126 are arranged so that the positions in the longitudinal direction of the NOx sensor element 1 are different from each other.

  Therefore, the electrode pad 124 and the electrode pads 125 and 126 can be compared to the case where the electrode pad 124 and the electrode pads 125 and 126 are arranged so that the positions in the longitudinal direction of the NOx sensor element 1 are the same. The distance between can be increased. Therefore, the distance between the through hole 114 corresponding to the electrode pad 124 and the through holes 115 and 116 corresponding to the electrode pads 125 and 126 can be increased, and the high voltage applied to the electrode pads 125 and 126 is increased. It is possible to prevent the characteristics of the second pump current Ip2 output from the electrode pad 124 from being deteriorated due to the influence of the above.

  Further, the through hole 114 corresponding to the electrode pad 124 is disposed on the rear end side of the electrode pad 124. Further, the through hole 115 corresponding to the electrode pad 125 is disposed on the tip side of the electrode pad 125. Further, the through hole 116 corresponding to the electrode pad 126 is disposed on the tip side of the electrode pad 126.

  For this reason, when the through hole 114 corresponding to the electrode pad 124 is disposed on the tip side in the electrode pad 124, or the through hole 115, 116 corresponding to the electrode pad 125, 126 is located behind the electrode pad 125, 126. The distance between the through-hole 114 corresponding to the electrode pad 124 and the through-holes 115 and 116 corresponding to the electrode pads 125 and 126 can be further increased as compared with the case where it is disposed on the end side.

  Further, the electrode pad 121 covers a range from the longitudinal position NI1 to the longitudinal position NI2 along the longitudinal direction (see the longitudinal range NH1 in FIG. 3) when projected in the opposing direction of the NOx sensor element 1. In the region, the electrode pads 125 are arranged so as to overlap with each other.

  Similarly, the electrode pad 122 is arranged so that there is a portion overlapping the electrode pad 126 in the region extending in the longitudinal direction range NH1. Further, the electrode pad 123 has a portion overlapping the electrode pad 124 in a region extending from the longitudinal position NI3 along the longitudinal direction to the longitudinal position NI4 (see the longitudinal range NH2 in FIG. 3). Has been placed.

Therefore, if the overlapping part is a part (hereinafter, also referred to as a conductive contact part) that makes an assembly part such as an electrode fitting conductively contacted, the arrangement of the conductive contact part in the protective layer 7 and the conductive contact part in the heater part 5 will be described. Can be made the same. For this reason, assembly parts having the same shape can be assembled on the front surface side (that is, the protective layer 7 side) and the back surface side (that is, the heater portion 5 side) of the NOx sensor element 1 as described above. According to the sensor element 1, even if the distance between the through holes is increased, assembly parts having the same shape can be assembled on the front surface side and the back surface side of the NOx sensor element 1.

  Further, the electrode pad 124 and the electrode pads 125 and 126 are disposed so that the positions in the longitudinal direction of the NOx sensor element 1 do not overlap. Therefore, the distance between the through hole 114 and the through holes 115 and 116 is made larger than when the electrode pad 124 and the electrode pads 125 and 126 are arranged so that the positions in the longitudinal direction overlap each other. can do.

  The heater unit 5 is disposed closer to the second pump cell 13 than the first pump cell 11, and electrode pads 124, 125, and 126 are disposed on the heater unit 5. For this reason, when the heater unit 5 is arranged closer to the second pump cell 13 than the first pump cell 11, the through-hole 114, rather than the electrode pads 124, 125, 126 are arranged on the protective layer 7. The lengths 115 and 116 can be shortened.

  The electrode pad 125 and the electrode pad 126 are arranged so that the positions of the NOx sensor element 1 in the longitudinal direction are the same. The electrode pads 121 and 122 are arranged on an insulating member (protective layer 7) different from the insulating member (heater part 5) on which the electrode pads 125 and 126 are arranged, and are projected in the direction facing the NOx sensor element 1. When this is done, the electrode pads 125 and 126 are arranged so as to overlap with each other. Further, the through holes (that is, the through holes 111 and 112) formed to bury the conductors connected to the electrode pads 121 and 122 are arranged so that the positions in the longitudinal direction of the NOx sensor element 1 are different from each other. The

  For this reason, the distance between the through hole 111 and the through hole 112 can be made larger than the case where the through holes 111 and 112 are arranged so that the positions in the longitudinal direction of the NOx sensor element 1 are the same. it can.

  In addition, the through holes 111 to 116 are not formed in portions where the electrode pads 121 to 126 overlap (that is, regions extending in the longitudinal direction ranges NH1 and NH2). For this reason, the conductive contact portion does not enter the hole (hole), and the electrode pads 121 to 126 can be prevented from peeling off.

  In the embodiment described above, the NOx sensor element 1 is the gas sensor element in the present invention, the first solid electrolyte layer 31 is the first solid electrolyte body in the present invention, the first inner electrode 35 and the first outer electrode 37 are the first in the present invention. One electrode, detection solid electrolyte layer 51 is the second solid electrolyte body in the present invention, detection electrode 55 and reference electrode 57 are the second electrode in the present invention, and second solid electrolyte layer 41 is the third solid electrolyte in the present invention. The body, the second inner electrode 45 and the second outer electrode 47 are the third electrode in the present invention, the sensor main body portion 3 is the gas sensor main body portion in the present invention, the protective layer 7 is the first insulating member in the present invention, and the heater portion 5 is the main electrode. The second insulating member and electrode pad 124 in the present invention are the first electrode pad in the present invention, the electrode pad 125 is the second electrode pad and the electrode pad 126 in the present invention. A third electrode pad in the invention.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, As long as it belongs to the technical scope of this invention, a various form can be taken.
For example, in this embodiment, the electrode pad 124 that outputs the second pump current Ip2 and the electrode pads 125 and 126 for energizing the heater unit 5 are arranged on the same insulating member (heater unit 5). Indicated. However, for example, the electrode pads 124 may be disposed on the protective layer 7 and the electrode pads 125 and 126 may be disposed on the heater unit 5.

3 is an internal configuration diagram of a sensor body 3 of a NOx sensor element 1. FIG. 2 is an exploded perspective view schematically showing a configuration of a NOx sensor element 1. FIG. 3 is a plan view of a protective layer 7 and a second alumina layer 102 showing the arrangement of electrode pads 121 to 126. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... NOx sensor element, 3 ... Sensor main-body part, 5 ... Heater part, 7 ... Protective layer, 11 ... 1st pump cell, 12 ... Oxygen concentration detection cell, 13 ... 2nd pump cell, 14, 15 ... Insulating layer, 16 ... First diffusion resistor, 17 ... second diffusion resistor, 18 ... reference oxygen chamber, 19 ... introduction path, 21 ... first porous electrode, 22 ... protective layer, 23 ... porous electrode for detection, 25 ... second Porous electrode, 31 ... first solid electrolyte layer, 35 ... first inner electrode, 37 ... first outer electrode, 41 ... second solid electrolyte layer, 45 ... second inner electrode, 47 ... second outer electrode, 51 ... Detecting solid electrolyte layer, 55 ... detecting electrode, 57 ... reference electrode, 59 ... first measuring chamber, 61 ... second measuring chamber, 101,102 ... second alumina layer, 111-116 ... through hole, 121- 126 ... Electrode pad

Claims (5)

A plate-shaped first solid electrolyte body having oxygen ion conductivity;
A pair of first electrodes disposed on the first solid electrolyte body;
A plate-shaped second solid electrolyte body disposed opposite to the first solid electrolyte body and having oxygen ion conductivity;
A pair of second electrodes disposed on the second solid electrolyte body;
A plate-shaped third solid electrolyte body disposed opposite to the second solid electrolyte body on the opposite side of the first solid electrolyte body across the second solid electrolyte body and having oxygen ion conductivity;
A pair of third electrodes disposed on the third solid electrolyte body;
A first measurement chamber disposed between the first solid electrolyte body and the second solid electrolyte body and into which a gas to be measured is introduced from the outside, wherein one electrode of the pair of first electrodes; A first measurement chamber formed to accommodate one electrode of a pair of second electrodes;
A second measurement chamber into which one of the pair of third electrodes is accommodated and into which the measurement target gas introduced into the first measurement chamber is introduced, and the measurement target gas A gas sensor main body for detecting the concentration of a specific gas component in the inside,
A plate-shaped first insulating member that is disposed on one side of the gas sensor body in the opposing direction and has an insulating property;
A plate-shaped second insulating member having insulation, which is disposed on a surface opposite to the side on which the first insulating member is disposed in the gas sensor main body and has a heating resistor embedded therein. A gas sensor element formed in a plate shape extending in the longitudinal direction,
Three electrode pads arranged on the surface of the first insulating member and three on the surface of the second insulating member, and formed in a shape extending in the longitudinal direction of the gas sensor element;
A through hole formed through each of the six electrode pads in the opposing direction of the gas sensor element to connect the electrode pad and any one of the first electrode, the second electrode, and the third electrode. And
Each of the three electrode pads arranged on the first insulating member overlaps with one of the three electrode pads arranged on the second insulating member when projected in the facing direction of the gas sensor element. Are arranged to exist
Of the six electrode pads, the first electrode pad electrically connected to the third electrode housed in the second measurement chamber through the through hole is formed on the same insulating member as the first electrode pad. Among the three electrode pads arranged, the electrode pads are arranged on the most rear end side in the longitudinal direction,
Of the six electrode pads, the second electrode pad electrically connected to one end of the heating resistor through the through hole, and the other end of the heating resistor to the electric through the through hole. The third electrode pad to be connected is disposed on the same insulating member,
The second electrode pad and the third electrode pad are disposed on the distal end side in the longitudinal direction among the three electrode pads disposed on the same insulating member as the second electrode pad and the third electrode pad. Two electrode pads,
A first through hole connected to the first electrode pad is disposed on a rear end side in the longitudinal direction in the first electrode pad;
The second through hole and the third through hole connected to the second electrode pad and the third electrode pad are respectively disposed on the front end side in the longitudinal direction in the second electrode pad and the third electrode pad. The gas sensor element characterized by the above-mentioned. 2. The gas sensor according to claim 1, wherein the first electrode pad, the second electrode pad, and the third electrode pad are arranged such that positions in the longitudinal direction of the gas sensor element do not overlap with each other. element. The second insulating member is disposed closer to the third solid electrolyte body than the first solid electrolyte body;
3. The three electrode pads disposed on the second insulating member are the first electrode pad, the second electrode pad, and the third electrode pad. 3. Gas sensor element. The second electrode pad and the third electrode pad are arranged such that the positions of the gas sensor elements in the longitudinal direction are the same,
The second electrode pad and the third electrode pad are disposed on an insulating member different from the insulating member on which the second electrode pad and the third electrode pad are disposed, and when projected in the facing direction of the gas sensor element. The two through-holes connected to the two electrode pads are arranged so that the positions of the gas sensor elements in the longitudinal direction are different from each other. The gas sensor element according to any one of claims 1 to 3, wherein the gas sensor element is characterized.   The gas sensor element according to any one of claims 1 to 4, wherein the through hole is not formed in the overlapping portion.

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