Gas sensor

Abstract

Gas sensor, comprehensive: a gas sensor element (10, 10A, 10B) having the form of a plate extending in a longitudinal direction (D1) and configured by lamination of three or more ceramic layers, wherein the gas sensor element (10, 10A, 10B) has an electrode contact surface (PdP to PdW) arranged on an outer surface of the gas sensor element (10, 10A, 10B) and penetration holes (C1P to C6W) extending in a direction (D2) of the lamination through two or more of the corresponding ceramic layers arranged between an inner conductor provided in the gas sensor (10, 10A, 10B) and the electrode contact surfaces (PdP to PdW), wherein the gas sensor element (10, 10A, 10B) has a conductor track (CLP to CLW) formed therein such that the conductor track (CLP to CLW) passes through the penetration holes (C1P to C6W) formed in various of the corresponding ceramic layers and electrically connects the inner conductor and the electrode contact surface (PdP to PdW), and The conductor track (CLP to CLW) comprises a conductor track of type 1 (CLP; CLP to CLW; CLP) which passes through a plurality of penetration holes (C1P to C6W) which, viewed in the direction (D2) of the lamination, are arranged in a non-overlapping manner, wherein, viewed in the direction (D2) of the lamination, a plurality of penetration holes (C1P to C6W) through which the conductor track of type 1 (CLP; CLP to CLW; CLP) passes are arranged at least longitudinally (D1) offset from one another, such that the penetration holes (C1P to C6W) arranged at least longitudinally (D1) offset from one another are electrically connected to each other.

Description

Technical field

[0001] The present invention relates to a gas sensor. Background of the invention

[0002] Gas sensors are traditionally used to detect specific gas components, such as nitrogen oxides (NOx). XTo detect oxygen and the concentration of a specific gas component, a gas sensor is known. Among these gas sensors, one is known to have an elongated, plate-shaped gas sensor element comprising a plurality of layered ceramic layers (e.g., solid electrolyte layers and aluminum oxide substrates). A known technique for connecting internal conductors (e.g., a heat-generating resistor and electrodes) of the gas sensor element to corresponding electrode contact surfaces provided on the surface of the gas sensor element uses penetration holes (e.g., through holes and via holes) extending through individual layers of the ceramic layers and conductive traces extending through a plurality of penetration holes. Publication 1: JP 2007 - 40 820 A Publication 2: JP 2008 - 170 341 A Publication 3: US 2008 / 0 016 942 A1 Publication 4: DE 10 2006 055 797 A1 Publication 5: US 2007 / 0 060 970 A1 Publication 6: US 6 120 708 A

[0003] Document 3 discloses a gas sensor with a longitudinally extending detection element in which several ceramic layers are stacked and a detection section is provided at one of its front ends. Through holes are provided in each of the ceramic layers.

[0004] Document 4 discloses a gas sensor with a sensor body composed of several substrates, wherein through holes introduced into the substrates are arranged offset from one another.

[0005] Publication 5 discloses electrical connections between ceramic layers that are arranged offset from one another and connected by means of conductor layers.

[0006] Document 6 discloses conductive vias in ceramic layers, which are arranged offset from one another and connected by means of conductor layers. Problems to be solved by the invention

[0007] If two or more ceramic layers are arranged between an inner conductor and a corresponding electrode contact surface provided on the surface of the gas sensor element, a penetration hole must be provided in each of the ceramic layers. In the gas sensors known from Documents 1 and 2, the penetration holes provided in the corresponding ceramic layers are aligned one above the other when the gas sensor element is viewed along one direction of the lamination (the penetration holes are aligned with each other in the lamination direction). However, if a gas sensor of such a configuration is subjected to vibration due to external influence or shock, then cracks or similar defects are likely to occur in the gas sensor element. Summary of the invention

[0008] The present invention was made in view of the above-mentioned problem and it is an objective to provide a technique for maintaining the strength of the gas sensor element by preventing the occurrence of cracks or the like in a gas sensor element, even when the gas sensor element is exposed to external influence or shock.

[0009] According to a first aspect (1) of the invention, this is achieved by providing a gas sensor according to claim 1.

[0010] According to the configuration described above, a multitude of the penetration holes used to form the type 1 conductor feedthroughs are not arranged on the same straight line parallel to the direction of lamination when viewed in the direction of lamination. Consequently, even if the gas sensor element vibrates due to external forces or shocks, the occurrence of cracks or the like is suppressed, thus maintaining the robustness of the gas sensor element. The expression used herein, "the penetration holes are arranged such that they are not superimposed when viewed in the direction of lamination," means that when the penetration holes formed in the ceramic layers are projected in the direction of lamination onto an outermost ceramic layer, the penetration holes are arranged in different configurations (i.e.,(that the projected penetration holes are arranged in such a way that they do not come into contact with each other). The three or more ceramic layers preferably comprise a support layer for carrying a . a heat-generating resistor, and a solid electrolyte layer comprising a pair of electrodes. The inner conductor is preferably a heat-generating resistor or one of the paired electrodes.

[0011] According to a preferred embodiment (2) of the aforementioned first aspect (1), the gas sensor further comprises a connection that is linked to the electrode contact surface and is designed to connect the electrode contact surface to an external circuit, and a mounting area for holding the gas sensor element. The conductor track of type 1 is arranged within an arrangement area between a contact position in which the connection is linked to the electrode contact surface and a mounting position in which the mounting area holds the gas sensor element.

[0012] Assuming that the contact position or the mounting position is subjected to external influence or vibration, and a conductor track is provided within an arrangement area between the contact position and the mounting position, the gas sensor element will vibrate along with the other end, which serves as a stationary end. It follows that cracks or similar defects are likely to occur starting from a penetration hole located within the arrangement area between the contact position and the mounting position.However, since the conductor track of type 1 is arranged within the arrangement area between the contact position and the mounting position, the formation of cracks or the like, originating from a penetration hole located within this arrangement area, is suppressed, even if the gas sensor element vibrates due to external influences or shocks, thereby maintaining the robustness of the gas sensor element. According to a preferred mode, the arrangement of at least one penetration hole of the plurality of penetration holes, through which the conductor track of type 1 passes, is arranged along the longitudinal direction within the arrangement area between the contact position, where the terminal and the electrode contact surface are in contact with each other, and the mounting position, where the mounting area holds the gas sensor element.

[0013] According to yet another preferred embodiment (3) of the above gas sensor according to (1) or (2) above, a plurality of the penetration holes through which the conductor track of type 1 passes are arranged offset from one another at least in the longitudinal direction when viewed in the direction of lamination.

[0014] According to the configuration described above, a large number of the penetration holes through which the Type 1 conductor passes are not arranged perpendicular to the longitudinal direction along a lateral direction (the direction along the width of the gas sensor element). If the gas sensor element is viewed along an imaginary cross-section made along the width direction and passing through one of the penetration holes used to form the Type 1 conductor, then this configuration can consequently prevent the problem of the gas sensor element having an area with a very high penetration hole density. Even if the gas sensor element vibrates due to external influences or shocks, the formation of cracks or the like is accordingly prevented, thus maintaining the robustness of the gas sensor element. The expression "the penetration holes...""[are] at least longitudinally offset from one another" means that when the penetration holes formed in the corresponding ceramic layer are projected onto an outermost ceramic layer, the penetration holes differ from one another at least in their longitudinal arrangement. The penetration holes may differ from one another with respect to the lateral direction (a direction perpendicular to the longitudinal direction), or at least some of the penetration holes may be in the same position. For example, the penetration holes may be arranged on the same straight line parallel to the longitudinal direction, or they may be arranged on a straight line that intersects the longitudinal direction at an acute angle.

[0015] According to yet another preferred embodiment (4) of the gas sensor according to one of the above configurations (1) to (3), the gas sensor element comprises a plurality of electrode contact surfaces and an outermost layer, which serves as the outermost surface thereof and is connected to the plurality of electrode contact surfaces. The outermost layer has a plurality of penetration holes formed therein. Of the pairs formed by any two of the plurality of penetration holes formed in the outermost layer, a pair formed by two penetration holes arranged closest to each other is used to form two conductor tracks passing through the corresponding penetration holes, each of the conductor tracks being of type 1.

[0016] If the gas sensor element vibrates due to external influences or shocks, cracks or similar defects are highly likely to occur, originating at the closest penetration holes in the outermost layer. However, according to the configuration described above, the two closest conductor tracks are Type 1 conductor tracks. Therefore, even if the gas sensor element vibrates due to external influences or shocks, the occurrence of cracks or similar defects originating at the two closest penetration holes in the outermost layer can be prevented, thus maintaining the robustness of the gas sensor element.

[0017] According to yet another preferred embodiment (5) of the gas sensor according to (4) above, all of the plurality of conductor tracks passing through a plurality of penetration holes formed in the outermost layer are conductor tracks of type 1.

[0018] When the gas sensor element is viewed along the direction of the lamination according to the configuration described above, the penetration holes are never arranged on the same straight line parallel to the direction of the lamination. Therefore, the formation of cracks or similar defects is prevented, even if the gas sensor element vibrates due to external influences or shocks, thus maintaining the robustness of the gas sensor element.

[0019] According to yet another preferred embodiment (6) of the above gas sensor according to (4) or (5), the number of penetration holes occurring in each of the ceramic layers is at most 1 when the gas sensor element is viewed in the direction of an imaginary section perpendicular to the longitudinal direction.

[0020] When the gas sensor element is viewed along an imaginary section perpendicular to its longitudinal direction, as described above, a large number of penetration holes do not appear in each of the ceramic layers. This prevents the problem of the gas sensor element, viewed along the imaginary section, exhibiting an area with a very high penetration hole density. Therefore, the formation of cracks or similar defects is sufficiently suppressed, even if the gas sensor element vibrates due to external influences or shocks, thus maintaining the gas sensor element's robustness to a sufficient degree.When the gas sensor element is viewed along the imaginary section perpendicular to the longitudinal direction, then the total number of penetration holes in each of the ceramic layers (the total number of penetration holes intersecting a single imaginary section) is preferably at most 1.

[0021] According to yet another preferred embodiment (7) of one of the above gas sensors (4) to (6), the outermost layer comprises aluminium oxide as a main component; the gas sensor element further comprises a solid electrolyte layer; and the distance between the two penetration holes of the plurality of penetration holes that are arranged closest to each other and formed in the outermost layer is shorter than the distance between two penetration holes formed in the solid electrolyte layer through which the two corresponding conductors of type 1 pass, which pass through the two penetration holes of the outermost layer.

[0022] According to the configuration described above, the distance between the two penetration holes formed in the solid electrolyte layer is greater than the distance between the two penetration holes that are closest to each other in the outermost layer, which contains aluminum oxide as its main component. Consequently, leakage current through the solid electrolyte layer can be prevented.

[0023] According to yet another preferred embodiment (8) of the above gas sensor (7), the inner conductor consists of at least one heat-generating resistor for heating the gas sensor element and a pair of electrodes which are provided on the solid electrolyte layer and partially form a cell.

[0024] The configuration described above makes it possible to use the present invention for a conductor track that connects a heat-generating resistor or an electrode of the gas sensor element to an electrode contact surface provided on the surface of the gas sensor element. Configuration (8) can be applied to a gas sensor corresponding to one of the above gas sensors (1) to (6), in which the gas sensor element further comprises a solid electrolyte layer.

[0025] The present invention can be implemented in various forms, for example in a gas sensor element and in a gas sensor using the gas sensor element. Brief description of the characters Fig. Figure 1 shows a cross-sectional view representing a gas sensor 200 according to an embodiment of the present invention. Fig. Figure 2 shows a cross-sectional view of a NO X -Sensor elements 10. Fig. Figure 3 shows a perspective exploded view of the NO X -Sensor elements 10. Fig. Figure 4 shows an explanatory illustration depicting arrangements of penetration holes along a direction D2 of the lamination. Fig. Figure 5 shows an illustrative view depicting arrangements of penetration holes along a lateral direction D3. Fig. Figure 6 shows a perspective exploded view of another embodiment of an NO. X -Sensor elements. Fig. Figure 7 shows an explanatory illustration depicting arrangements of penetration holes along the direction D2 of the lamination. Fig. Figure 8 shows a perspective exploded view of another embodiment of a gas sensor element. Fig. Figure 9 shows a diagram illustrating the results of a stress test performed with samples of the first embodiment and samples of a comparison example. Detailed description of preferred embodiments

[0026] Next, embodiments of the present invention are described with reference to the figures in the following sections. However, the present invention should not be understood as being limited to these embodiments. A. First embodiment B. Second embodiment C. Third embodiment D. Experimental Examples E. Modifications A. First embodiment

[0027] Fig. Figure 1 shows a cross-sectional view representing a gas sensor 200 according to an embodiment of the present invention. The gas sensor 200 is attached to an exhaust pipe of an internal combustion engine (not shown) and is designed to measure the concentration of nitrogen oxides (NOx). X ) to measure (the gas sensor 200 will also be referred to as "NO" in the following) X -Sensor 200“). Fig. Figure 1 shows a section of the NO X -Sensors 200 along a parallel to a longitudinal direction D1. In the following description, the downward direction (bottom side) - in Fig. 1 “Forward direction” (front) FWD of the NE X -Sensors 200 and the upward direction (top side) in Fig. 1 becomes “reverse direction” (rear side) BWD of the NE X -Sensors 200 is named.

[0028] The NO X -Sensor 200 comprises a tubular metallic sleeve 138, a plate-shaped NO X-Sensor element (gas sensor element) 10, extending in the longitudinal direction D1, a tubular ceramic sleeve 106, which detects the NO X -Sensor element 10 surrounds an insulating contact part 166, and six connection terminals 110 (in Fig. (Figure 1 shows four pieces). The metallic sleeve 138 has a threaded area 139 formed on its outer surface and is intended for attachment to the exhaust pipe. The ceramic sleeve 106 is arranged such that it protects the NO X -Sensor element 10 surrounds in the radial direction. The insulating contact part 166 has a contact insertion hole 168 that extends longitudinally in direction D1. The insulating contact part 166 is arranged such that the wall surface of the contact insertion hole 168 forms a rear end region of the NO X -Sensor elements 10 surround. The connection terminals 110 are between the NO X-Sensor element 10 and the insulation contact part 166 are arranged.

[0029] The metallic sleeve 138 is essentially tubular and has a through-hole 154, which extends laterally, and a projection 152 that projects radially into the through-hole 154. The metallic sleeve 138 holds the NO X -Sensor element 10 in the through hole 154 such that the forward end of the NO X -Sensor element 10 is located outside the through-hole 154 on the front FWD, whereas the rear end of the NO X The sensor element 10 is arranged outside the through-hole 154 on the rear side BWD. The projection 152 comprises a tapered surface inclined with respect to a plane perpendicular to the longitudinal direction D1. The tapered surface is designed such that the diameter on the front side FWD is smaller than the diameter on the rear side BWD.

[0030] A ceramic holder 151, powder layers 153 and 156 (hereinafter referred to as talc rings 153 and 156), and the ceramic sleeve 106 are stacked in the through-hole 154 of the metallic sleeve 138 in this order, from front to back. The ceramic holder 151, the talc rings 153 and 156, and the ceramic sleeve 106 all correspond to the "retaining area" in the claims. Hereinafter, these parts are all referred to as the "retaining area 160". Each of these parts takes the form of a ring to hold the NO X -Sensor element 10 to be surrounded in the circumferential direction such that the NO X -Sensor element 10 is held. The NO X -Sensor element 10 is held by the mounting area 160.

[0031] A crimp seal 157 is arranged between the ceramic sleeve 106 and a rear end region 140 of the metallic sleeve 138. A metal holder 158 is arranged between the ceramic holder 151 and the projection 152 of the metallic sleeve 138 for holding the talc ring 153 and the ceramic holder 151 for gas sealing. The rear end region 140 of the metallic sleeve 138 is crimped such that the ceramic sleeve 106 is pressed forward by means of the crimp seal 157.

[0032] As in Fig. Figure 1 shows an outer protector 142 and an inner protector 143 on the outer circumference of a forward end region (a lower end region in Fig. 1) attached to the metallic sleeve 138 by welding or the like. The protectors 142 and 143, which are assembled in a dual structure, are made of metal (for example, stainless steel) and have a multitude of holes and cover one of the NO X-Sensor element 10 protruding area.

[0033] An outer tube 144 is attached to the outer circumference of a rear end of the metallic sleeve 138. A grommet 150 is attached to a rear end opening region (upper end in Fig. 1) of the outer tube 144. The grommet 150 has guide insertion holes 161 formed therein. Six conductor wires 146 (in Fig. (Only five conductor wires 146 are shown) are inserted through the corresponding guide entry holes 161. These conductor wires 146 are connected to corresponding electrode contact surfaces located on the outer surface of a rear end region of the NO. X -Sensor elements 10 are provided, electrically connected.

[0034] The insulating contact part 166 is surrounded by a rear end area (upper end area in Fig. 1) of the NO X -Sensor elements 10 arranged, wherein the NO XThe sensor element 10 protrudes from the rear end region 140 of the metallic sleeve 138. The insulating contact part 166 is located around the electrode contact surfaces on the surface of the rear end region of the NO. X -Sensor element 10. The insulating contact part 166 has a tubular shape; it has the contact insertion hole 168, which extends in the longitudinal direction D1; and it has a flange region 167 projecting radially outwards from its outer surface. A retaining element 169 is inserted between the insulating contact part 166 and the outer tube 144. The retaining element 169 is connected to the outer tube 144 and the flange region 167, thereby holding the insulating contact part 166 within the outer tube 144.

[0035] Fig. 2 shows a cross-sectional view of the NO X -Sensor element 10. The cross-sectional view is parallel to the longitudinal direction D1. In Fig. 2 corresponds to the left-hand direction of the forward direction (front) FWD of the NO X -Sensor element 10 and the direction to the right corresponds to the reverse direction (rear side) BWD of the NO X -Sensor element 10. The NO X Sensor element 10 has a structure in which an insulating layer 14e, a first solid electrolyte layer 11a, an insulating layer 14a, a second solid electrolyte layer 12a, an insulating layer 14b, a third solid electrolyte layer 13a, and insulating layers 14c and 14d are stacked in that order. These layers are stacked along a direction D2 of the lamination perpendicular to the longitudinal direction D1. For the sake of simplicity, the insulating layer 14e is shown in Fig. 2 separated from the first solid electrolyte layer 11a. In fact, however, the insulating layer 14e is layered on top of the first solid electrolyte layer 11a. The insulating layer 14e, the first solid electrolyte layer 11a, the insulating layer 14a, the second solid electrolyte layer 12a, the insulating layer 14b, the third solid electrolyte layer 13a, and the insulating layers 14c, 14d, and 14e correspond to the “ceramic layers” in the claims. The insulating layers 14d and 14e correspond to the “outermost layer” in the claims.

[0036] A first measuring chamber 16 is formed between the first solid electrolyte layer 11a and the second solid electrolyte layer 12a. A gas GM to be measured is introduced from the outside into the first measuring chamber 16 by means of a first diffusion resistance 15a arranged at the left end (inlet) of the first measuring chamber 16. A second diffusion resistance 15b is arranged at an end of the first measuring chamber 16 opposite the inlet.

[0037] A second measuring chamber 18 is formed to the right of the first measuring chamber 16 and is connected to the first measuring chamber 16 by means of the second diffusion resistance 15b. The second measuring chamber 18 extends through the second solid electrolyte layer 12a and is formed between the first solid electrolyte layer 11a and the third solid electrolyte layer 13a.

[0038] A heater 50, extending along the longitudinal direction D1, is embedded between the insulating layers 14c and 14d. The heater 50 heats the gas sensor element 10 to a predetermined activation temperature to stabilize its operation by increasing the oxygen conductivity of the solid electrolyte layers. The heater 50 is a heat-generating resistor made of a conductive material, such as tungsten, and generates heat by means of supplied electrical energy. The heater 50 is supported by the two layers 14c and 14d. The heater 50 corresponds to the "heat-generating resistor" in the claims.

[0039] In the present embodiment, the solid electrolyte layers 11a, 12a, and 13a are formed using zirconium dioxide, which exhibits oxygen ion conductivity, as the main component. The insulating layers 14a to 14e are formed using aluminum oxide as the main component. The first diffusion resistance layer 15a and the second diffusion resistance layer 15b are formed using a porous material, such as aluminum oxide. As used herein, a "main component" means "a main material that is present in a ceramic layer in an amount of 50% by mass or greater." For example, the expression "the solid electrolyte layers are formed using zirconium dioxide as a main component" means that the solid electrolyte layers contain zirconium dioxide in an amount of 50% by mass or greater.Among the eight solid electrolyte and insulating layers, six layers 14e, 11a, 12a, 13a, 14c, and 14d are formed using appropriate material sheets (for example, ceramic sheets such as zirconium dioxide or aluminum oxide). The two insulating layers 14a and 14b are formed by screen printing on appropriate ceramic sheets. A lamination of green layers is fired, thereby increasing the NO. X -Sensor element 10 is formed.

[0040] The gas sensor element 10 has a first pump cell 11, an oxygen concentration detection cell 12 and a second pump cell 13.

[0041] The first pump cell 11 comprises the first solid electrolyte layer 11a, an inner first pump electrode 11c, and a first counter electrode (outer first pump electrode) 11b, which serves as a counter electrode to the inner first pump electrode 11c. The inner first pump electrode 11c and the outer first pump electrode 11b are arranged such that the first solid electrolyte layer 11a is held between them. The inner first pump electrode 11c faces the first measuring chamber 16. Platinum is primarily used to form the first inner pump electrode 11c and the outer first pump electrode 11b. The surface of the inner first pump electrode 11c is covered with a protective layer 11e, which is formed from a porous material.The outer first pump electrode 11b is covered with a porous material 1ld (for example, aluminium oxide) which is embedded in the insulating layer 14e at one of the outer first pump electrode llb prepared area and allows the passage of gas (such as oxygen).

[0042] The oxygen concentration detection cell 12 comprises the second solid electrolyte layer 12a, a detection electrode 12b, and a reference electrode 12c. The detection electrode 12b and the reference electrode 12c are arranged such that the second solid electrolyte layer 12a is held between them. The detection electrode 12b is located downstream of the inner first pump electrode 12c and faces the first measuring chamber 16. Platinum is predominantly used to form the detection electrode 12b and the reference electrode 12c.

[0043] The insulating layer 14b has a recess designed to accommodate the reference electrode 12c in contact with the second solid electrolyte layer 12a. The recess is filled with a porous material, forming a reference oxygen chamber 17. Applying an extremely weak, constant current to the oxygen concentration detection cell 12 causes oxygen to be transported from the first measuring chamber 16 into the reference oxygen chamber 17. This maintains the oxygen concentration in the reference oxygen chamber 17 at a predetermined level. Consequently, the oxygen concentration in the reference oxygen chamber 17 serves as a reference oxygen concentration.

[0044] The second pump cell 13 comprises the third solid electrolyte layer 13a, an inner second pump electrode 13b arranged on a surface of the third solid electrolyte layer 13a facing the second measuring chamber 18, and a second counter electrode (counter electrode of the second pump electrode) 13c, which is a counter electrode to the inner second pump electrode 13b. Platinum is primarily used to form the inner second pump electrode 13b and the counter electrode 13c to the second pump electrode. The counter electrode 13c to the second pump electrode is arranged on a region of the third solid electrolyte layer 13a corresponding to the recess of the insulating layer 14b and is oriented towards the reference electrode 12c with the reference oxygen chamber 17 located between them. Each of the first solid electrolyte layer 11a, the second solid electrolyte layer 12a and the third solid electrolyte layer 13a corresponds to the “solid electrolyte layer” in the claims.A pair consisting of the inner first pump electrode 11c and the outer first pump electrode 11b, a pair consisting of the detection electrode 12b and the reference electrode 12c and a pair consisting of the inner second pump electrode 13b and the counter electrode 13c to the second pump electrode all correspond to the “one pair of electrodes” of the corresponding solid electrolyte layer in the claims.

[0045] Fig. Figure 2 also shows a control unit CU for the NO X -Sensor 200 (NO X -Sensor element 10). The heater 50 and the electrodes 11b, 11c, 12b, 12c, 13b and 13c are connected to the control unit CU by means of the in Fig. The connection terminals 110 and the connecting wires 146 are shown in Figure 1. The control unit CU supplies the heater 50 with energy, as described later. The control unit CU sends signals to and receives signals from the electrodes 11b, 11c, 12b, 12c, 13b and 13c, thereby controlling the NO X-Sensor 200 (NO X -Sensor element 10). In the present embodiment, the control unit CU is an electronic circuit formed using operational amplifiers, etc. The control unit CU can be formed using a computer that has a CPU and memory.

[0046] Next, an exemplary company from the NO will be presented. X-Sensor elements 10 are described. When an engine is started, the control unit CU is started first. The control unit CU supplies the heater 50 with energy. The heater 50 heats the first pump cell 11, the oxygen concentration detection cell 12, and the second pump cell 13 to an activation temperature. When cells 11 to 13 have reached the activation temperature, the control unit CU applies a current to the first pump cell 11. This causes the first pump cell 11 to pump excess oxygen contained in a gas GM (exhaust gas) to be measured, which has been introduced into the first measuring chamber 16, from the inner first pump electrode 11c to the first counter electrode 11b.

[0047] The control unit CU regulates the electrode-to-electrode voltage (terminal-to-terminal voltage) of the first pump cell 11, so that the electrode-to-electrode voltage (terminal-to-terminal voltage) of the oxygen concentration detection cell 12 adjusts to a constant voltage V1 (for example, 425 mV). The voltage of the oxygen concentration detection cell 12 indicates the oxygen concentration of the detection electrode 12b. This control adjusts the oxygen concentration of the first measuring chamber 16 such that no decomposition of NO occurs. X is caused.

[0048] The gas GN to be measured, whose oxygen concentration is adjusted, flows towards the second measuring chamber 18. The control unit CU applies an electrode-to-electrode voltage (terminal-to-terminal voltage) to the second pump cell 13. The voltage is set to a sufficiently high constant voltage to prevent the decomposition of NO contained in the gas GN to be measured.X in oxygen and nitrogen (the voltage is greater than the control voltage of the oxygen concentration detection cell 12 and is, for example, 450 mV). By applying this voltage, NO contained in the gas GN to be measured is reduced. X decomposed into nitrogen and oxygen.

[0049] The control unit CU applies a second pump current to the second pump cell 13, so that through the decomposition of NO X The generated oxygen is pumped out of the second measuring chamber 18. Since there is a gap between the second pump stream and the NO X -Concentration where a linear relationship exists, the concentration of NO can be X The gas GN to be measured is detected by current measurement.

[0050] Fig. Figure 3 shows a perspective exploded view of the NO X -Sensor elements 10. Fig. Figure 3 shows a rear end region of the NO X-Sensor elements 10. The two insulation layers 14a and 14b are in Fig. 3 not shown. The six ceramic layers 14e, 11a, 12a, 13a, 14c and 14d are in Fig. 3 shown.

[0051] On the outer surface of the insulating layer 14e (the outer surface being a surface opposite a surface in contact with the first solid electrolyte layer 11a), three electrode contact surfaces PdP, PdQ, and PdR are formed. The insulating layer 14e has three through-holes C1P, C1Q, and C1R formed within it. Viewed in the direction D2 of the lamination, the three through-holes C1P, C1Q, and C1R are correspondingly formed in the three electrode contact surfaces PdP, PdQ, and PdR. Each through-hole corresponds to the "penetration hole" in the claims. A through-hole conductor is formed in each of the through-holes. A description of the through-hole conductors is omitted below.

[0052] The first solid electrolyte layer 11a has two through-holes formed therein, C2P and C2Q. Two connecting lines, PL1P and PL1Q, are formed between two ceramic layers 14e and 11a. The first connecting line, PL1P, connects the first through-hole C1P of the insulating layer 14e to the first through-hole C2P of the first solid electrolyte layer 11a. The second connecting line, PL1Q, connects the second through-hole C1Q of the insulating layer 14e to the second through-hole C2Q of the first solid electrolyte layer 11a. A connecting line 11bL is also formed between the two ceramic layers 14e and 11a to connect the through-hole C1R to the outer first pump electrode 11b (see Fig. 2) trained.

[0053] The second solid electrolyte layer 12a has two through-holes C3P and C3Q formed within it. Two connecting lines PL2P and PL2Q are formed between the two ceramic layers 11a and 12a. The first connecting line PL2P connects the first through-hole C2P to the first solid electrolyte layer 11a and the first through-hole C3P of the second solid electrolyte layer 12a. The second connecting line PL2Q connects the second through-hole C2Q of the first solid electrolyte layer 11a to the second through-hole C3Q of the second solid electrolyte layer 12a. Two further connecting lines 11cL and 12bL are formed between the two ceramic layers 11a and 12a. The pump electrode line 11cL connects the inner first pump electrode 11c (see Fig. 2) with the first through-hole C2P of the first solid electrolyte layer 11a. The detection electrode lead 12bL connects the detection electrode 12b (see Fig. 2) with the first through hole C3P of the second solid electrolyte layer 12a.

[0054] The insulation layer 14a (see Fig. 2) is arranged between the first solid electrolyte layer 11a and the second solid electrolyte layer 12a. The pump electrode lead 11cL is formed between the first solid electrolyte layer 11a and the insulating layer 14a. The detection electrode lead 12bL is formed between the insulating layer 14a and the second solid electrolyte layer 12a. It should be noted that the insulating layer 14a is not formed in a region where the connecting leads PL2P and PL2Q are formed. That is, the insulating layer 14a is designed in such a way that it avoids the two connecting leads PL2P and PL2Q. As a result, the connecting leads PL2P and PL2Q are in contact with the first solid electrolyte layer 11a and the second solid electrolyte layer 12a.

[0055] The third solid electrolyte layer 13a has a through-hole C4S formed within it. Three connecting lines 12cL, 13cL and 13bL are formed between the two ceramic layers 12a and 13a. The first connecting line 12cL connects the reference electrode 12c (see Fig. 2) with the second through-hole C3Q of the second solid electrolyte layer 12a. The second connecting line 13cL connects the counter electrode 13c to the second pump electrode (see Fig. 2) with the through-hole C4S of the third solid electrolyte layer 13a. The third connecting line 13bL connects the inner second pump electrode 13b (see Fig. 2) with the first through hole C3P of the second solid electrolyte layer 12a.

[0056] The insulation layer 14b (see Fig. 2) is arranged between the second solid electrolyte layer 12a and the third solid electrolyte layer 13a. The first connecting line 12cL is formed between the second solid electrolyte layer 12a and the insulating layer 14b. The second connecting line 13cL and the third connecting line 13bL are formed between the insulating layer 14b and the third solid electrolyte layer 13a.

[0057] The insulating layer 14c has a through-hole C5S. A connecting line PL4S is formed between the third solid electrolyte layer 13a and the insulating layer 14c to connect the through-hole C5S and the through-hole C4S of the third solid electrolyte layer 13a.

[0058] The insulating layer 14d has three through holes formed therein, C6S, C6T, and C6U. Three electrode contact surfaces, PdS, PdT, and PdU, are formed on the outer surface of the insulating layer 14d (the outer surface being a surface opposite a surface in contact with the insulating layer 14c). Viewed along the direction D2 of the lamination, the three through holes C6S, C6T, and C6U are formed accordingly in the three electrode contact surfaces PdS, PdT, and PdU.

[0059] The connecting lines 50La and 50Lb are formed between the insulating layer 14c and the insulating layer 14d. The first connecting line 50La connects the first through-hole C6T to the heater 50 (see Fig. 2) The second connecting line 50Lb connects the second connecting hole C6U to the heater 50.

[0060] The three conductor tracks CLP, CLQ and CLS are in Fig. Figure 3 shows the first conductor track, CLP, passing through the three through-holes C1P, C2P, and C3P. The first conductor track, CLP, begins at the first electrode contact surface, PdP; passes via the connecting line, PL1P, through through-hole C1P, through-hole C2P, and the connecting line, PL2P; and reaches the through-hole C3P. The first conductor track, CLP, allows the first electrode contact surface, PdP, to be used as a common contact surface between the inner first pump electrode 11c, the detection electrode 12b, and the inner second pump electrode 13b.

[0061] The second conductor track, CLQ, passes through the three through-holes C1Q, C2Q, and C3Q. CLQ begins at the second electrode contact surface PdQ; passes via the connecting wire PL1Q through through-hole C1Q, through-hole C2Q, and the connecting wire PL2Q; and reaches through-hole C3Q. CLQ allows the second electrode contact surface PdQ to be used as a contact surface for the reference electrode 12c.

[0062] The third conductor track, CLS, passes through the three contact holes C6S, C5S, and C4S. CLS begins at the electrode contact surface PdS; passes through through hole C6S, through hole C5S, and the connecting line PL4S; and reaches through hole C4S. The third conductor track, CLS, allows electrode contact surface PdS to be used as a contact surface for the counter electrode to the second pump electrode 13c.

[0063] The in Fig. The three connecting wires shown are made of a conductive material (for example, platinum or nickel). Various processes (for example, screen printing) are suitable for forming the connecting wires. Various processes are also suitable for forming the Fig. The three illustrated through-holes are suitable. Through-holes are formed, for example, by cutting holes in ceramic green leaves. Before firing, the through-holes are filled with a conductive paste. In this way, through-hole conductors are formed by firing.

[0064] Fig. Figure 4 shows an explanatory view illustrating the arrangement of contact holes as seen in the direction of D2 of the lamination. Fig. 4 are the individual six ceramic layers 14e, 11a, 12a, 13a, 14c and 14d, as they appear in Fig. 3 are shown individually, or as a projection view, in which the lamination state of the six ceramic layers and the projection of through holes formed in the five ceramic layers 14e, 11a, 12a, 13a and 14c along the lamination direction onto the insulation layer 14d is shown. Fig. Figure 4 shows a view of the insulation layer 14e in the direction of the insulation layer 14d. In the projection view, filled dots denote through holes formed in the insulation layer 14e; double circles denote through holes formed in the insulation layer 14d; and dashed circles denote through holes formed in the interior of the gas sensor element 10.

[0065] The second electrode contact surface PdQ is formed in a central area of ​​a rear end region (end region in the rear direction BWD) of the insulating layer 14e. The two electrode contact surfaces PdP and PdR are formed in a region that is offset from the second electrode contact surface PdQ in the forward direction FWD. The first electrode contact surface PdP is located on one side with respect to a lateral direction D3 (on the left side in Fig. 4) arranged and the third electrode contact surface PdR is on the other side with respect to the lateral direction D3 (on the right side in Fig. 4) arranged. The lateral direction D3 is perpendicular to the longitudinal direction D1 as well as to the direction D2 of the lamination.

[0066] Looking towards D2 of the lamination, the three electrode contact surfaces PdU, PdS and PdT formed on the insulating layer 14d lie over the three electrode contact surfaces PdP, PdQ and PdR formed on the insulating layer 14e.

[0067] The three through-holes C1P, C2P and C3P, which form the first conductor track CLP, are located along the longitudinal direction D1 on one side relative to the lateral direction D3 of the gas sensor element 10 (on the left side in Fig. 4) arranged. Viewed in the direction D2 of the lamination, these through-holes C1P, C2P, and C3P are arranged such that they do not overlap. The first conductor track CLP corresponds to "the conductor track of type 1" in the claims. Viewed in the direction D2 of the lamination, a plurality of through-holes are used to form a conductor track of type 1 by creating the first conductor track CLP in the NO x-Sensor element 10 is formed in this way; in particular, the through holes C1P, C2P and C3P are not arranged on the same straight line parallel to the lamination. Even if the NO X -Sensor element 10 vibrates due to external influences or shock, the occurrence of cracks or the like is consequently suppressed, thereby increasing the resistance of the NO X -Sensor elements 10 can be retained.

[0068] According to the present embodiment, the through-hole C3P of the second solid electrolyte layer 12a is arranged such that it is offset from the through-hole C1P of the insulating layer 14e in the forward direction FWD. The through-hole C2P of the first solid electrolyte layer 11a is arranged such that it is offset from the through-hole C3P in the forward direction FWD. In this way, the three through-holes C1P, C2P, and C3P used to form the first conductor track CLP are arranged such that they are offset from each other in the longitudinal direction D1. That is, a plurality of through-holes C1P, C2P, and C3P used to form the first conductor track (type 1 conductor track) CLP are not arranged along the lateral direction D3. This avoids a problem whereby the NO X-Sensor element 10 exhibits an area of ​​excessively high fill rate (area rate) of through holes when the gas sensor element 10 is viewed along an imaginary section perpendicular to the longitudinal direction D1 (parallel to the lateral direction D3), which is viewed through one of the through holes used to form the first conductor track CLP of the plurality of through holes. Even if the NO X If sensor element 10 vibrates due to external influences or shocks, the formation of cracks or the like is consequently suppressed, thereby increasing the resistance of the NO. X -Sensor element 10 can be retained. The through-hole C6U of the insulation layer 14d is arranged such that it is offset from the through-hole C1P of the insulation layer 14e in the reverse direction BWD.

[0069] The three through-holes C1Q, C2Q, and C3Q, used to form the second conductor track CLQ, are arranged along the longitudinal direction D1 in a central region of a rear end 10BE of the gas sensor element 10. The two through-holes C1Q and C3Q are located in the same position. The remaining through-hole C2Q is positioned offset from the two through-holes C1Q and C3Q in the forward direction FWD.

[0070] The three through-holes C4S, C5S, and C6S used to form the third conductor track CLS are also arranged along the longitudinal direction D1 in a central region of the rear end 10BE of the gas sensor element 10. The two through-holes C5S and C6S and the through-holes C1Q and C3Q of the second conductor track CLQ are arranged in the same position. The remaining through-hole C4S is arranged such that it is offset from the through-hole C2Q of the first solid electrolyte layer 11a in the forward direction FWD.

[0071] The through-hole C1R of the insulation layer 14e is on the other side with reference to the lateral direction D3 (on the right side in Fig. 4) arranged. The first through-hole C6T of the insulation layer 14d is arranged such that it is offset from the through-hole C1R in the forward direction FWD.

[0072] If the gas sensor element 10 is oriented along an imaginary section (for example, each of the imaginary sections A1, A1 and A3) perpendicular to the longitudinal direction D1 (parallel to the lateral direction D3 (a direction perpendicular to the longitudinal direction D1 and the direction D2 of the lamination)), as in Fig. As shown in Figure 4, if the number of through holes occurring in each of the six ceramic layers (the number of through holes intersecting with a single imaginary cut) is at most 1, then the number of through holes occurring in each of the six ceramic layers is at most 1. This means that through holes in each of the six ceramic layers are not arranged along the lateral direction D3. It follows that a problem, therefore, when considering the imaginary cut A1, A2, and A3, which NO X -Sensor element 10 can be prevented from having an area with an excessively high fill rate (area rate) of through holes. Even if the NO X-Sensor element 10 vibrates due to external influences and shocks, thus suppressing the occurrence of cracks or the like, thereby increasing the resistance of the NO X -Sensor elements 10 can be retained.

[0073] Fig. Figure 5 shows an explanatory sectional view of the NO X -Sensor elements 10 along the longitudinal direction D1 and the one that leads through the through hole C1P (a section along the line A4-A4 in Fig. 4), as seen along the lateral direction D3, which represents the arrangement of through holes. Fig. Figure 5 shows a rear end region of the gas sensor element 10 and a region of the gas sensor element 10 held by the mounting area 160 (the ceramic sleeve 106). Fig. 5 shows the in Fig. The six ceramic layers shown in 3 and the through holes provided in the ceramic layers.

[0074] Fig. Figure 5 shows some of the six connection terminals 110P, 110Q, 110R, 110S, 110T and 110U. These connection terminals 110P, 110Q, 110R, 110S, 110T and 110U are in contact with the electrode contact surfaces PdP, PdQ, PdR, PdS, PdT and PdU respectively (see Figure 5). Fig. 4) The six connection terminals 110P, 110Q, 110R, 110S, 110T and 110U are in Fig. 1 designated by the common reference symbol “110”.

[0075] Position CP1, as depicted, represents a contact position along the longitudinal direction D1 that is closest to the mounting area 160 of the six contact positions between the connection terminals 110P to 110U and the electrode contact surfaces PdP to PdU. In the present embodiment, the four connection terminals 110P, 110R, 110T and 110U at position CP1 are in contact with the four electrode contact surfaces PdP, PdR, PdT and PdU, respectively.

[0076] In Fig. 5. A first arrangement area R1 extends along the longitudinal direction D1 from position CP1 to the mounting position in which the mounting area 160 is the NO. X -Sensor element 10 is held (in particular a holding position that is closest to position CP1). In the present embodiment, the three through-holes C1P, C2P and C3P, through which the first conductor track CLP (see Fig. 3 and Fig. 4) is arranged within the first arrangement area R1. This is for the following reason. If the connecting terminal 110 is exposed to external influences or vibration, for example, the connecting terminal 110 exerts a force on the NO at position CP1. X -Sensor element 10. This means that the NO X-Sensor element 10 vibrates in the mounting position held by the mounting area 160, which serves as a fixed end. Starting from a through-hole located within the first arrangement area R1, cracks or the like are therefore likely to occur. It follows that if a conductor track passing through a plurality of ceramic layers is to be formed within the first arrangement area R1, then, preferably as in the case of the present embodiment, the conductor track is the first conductor track CLP. Compared to a configuration in which through-holes are stacked on top of each other within the first arrangement area R1, this configuration produces the following effect: Even if the NO XIf sensor element 10 vibrates due to external influences or shocks, then the formation of cracks or the like originating from the through holes C1P, C2P and C3P, which are arranged within the first arrangement area R1, is suppressed, thereby increasing the shock resistance of the NO X -Sensor element 10 can be maintained. Since the conductor tracks can be formed within the first arrangement area R1 as described above, while the resistance of the NO X -Sensor element 10 is retained, the degree of freedom in the design of the NO can be increased. X -Sensor element 10 may be enlarged. Through holes may also be located closer to corresponding connecting objects (e.g., the inner first pump electrode 11c and the inner second pump electrode 13b) in the NO. XSensor element 10 can be arranged. Consequently, the cables for connecting through holes to corresponding connection objects can be shortened. Therefore, less material can be used to form the cables.

[0077] In the present embodiment, no mounting area is provided on the side opposite the mounting area 160 with respect to position CP1 (in the reverse direction BWD from position CP1). Even if, for example, external influences or vibrations exert forces on the NO X -Sensor element 10 at position CP1, in contrast to the first arrangement area R1, in a second arrangement area R2, which extends from position CP1 in the reverse direction BWD, then accordingly a corresponding area of ​​NO follows X-Sensor element 10 of the vibration, so that cracks or the like are unlikely to occur starting from a through-hole. Viewed in the direction of D2 of the lamination, according to the present embodiment, as shown in Fig. As shown in section 4, the four through holes C1Q, C3Q, C5S and C6S are located at the rear end 10BE of the NO. X The sensor elements are arranged one above the other. Despite this superimposed arrangement of the four through-holes, the occurrence of cracks or the like originating from the four through-holes is prevented, even when the NO X -Sensor element 10 is exposed to external influences or vibration, resulting in an excessive reduction in the resistance of the NO X-Sensor element 10 can be prevented. By using through holes arranged one above the other in two adjacent layers, the through holes can be easily connected to each other without using a connecting line extending between the two layers. B. Second embodiment

[0078] Fig. Figure 6 shows a perspective exploded view of another embodiment of the NO. X -Sensor element of the present invention. One in Fig. 6 shown NO X -Sensor element 10A differs from the NO. X -Sensor element 10 of the first embodiment, which is in Fig. Figure 3 illustrates the differences in four points. A first difference is that a conductor track CLV and an electrode contact surface PdV are provided for the detection electrode 12b. A second difference is that a conductor track CLW and an electrode contact surface PdW are provided for the inner second pump electrode 13b. A third difference is that the second connecting line PL2P and the through-hole C3P are not present. A fourth difference is that the three through-holes C3Q, C5S, and C6S are offset from each other in the longitudinal direction D1 so that they do not overlap when viewed in the direction D2 of the lamination. Other configurational features are similar to those of the NO. X -Sensor element 10 of the first embodiment, which is in Fig. 3 is shown. The NO X -Sensor element 10A can be used in conjunction with the gas sensor element 10 of the first embodiment when used in the gas sensor 200, which is in Fig. The figure shown in Figure 1 is replaced. In this case, two connection terminals are added in contact with the two additional corresponding electrode contact surfaces PdV and PdW. In addition, eight conductor wires 146 are used, which are connected to the corresponding eight connection terminals.

[0079] First, the conductor track CLV is described. The electrode contact surface PdV is formed on the outer surface of the insulating layer 14e. The electrode contact surface PdV is located on a side opposite the second electrode contact surface PdQ with respect to the lateral direction D3 (on an adjacent side in Fig. 6) A through-hole C1V is formed in the insulating layer 14e. The through-hole C1V is located within and connected to the electrode contact surface PdV. A through-hole C2V is formed in the first solid electrolyte layer 11a near the insulating layer 14e. A connecting conductor PL1V is formed between the two ceramic layers 14e and 11a to connect the two through-holes C1V and C2V. The detection electrode conductor 12bL is connected to the through-hole C2V on one side of the first solid electrolyte layer 11a opposite the insulating layer 14e. The conductor CLV passes through the two through-holes C1V and C2V. The conductor CLV allows the electrode contact surface PdV to be used as a contact surface for the detection electrode 12b.

[0080] Next, the conductor track CLW is described. The electrode contact surface PdW is formed on the outer surface of the insulating layer 14d. The electrode contact surface PdW is arranged such that it is offset from the electrode contact surface PdU in the reverse direction BWD. A through-hole C6W is formed in the insulating layer 14d. The through-hole C6W is located within and connected to the electrode contact surface PdW. A through-hole C5W is formed in the insulating layer 14c near the insulating layer 14d. A connecting conductor PL5W is formed between the two ceramic layers 14c and 14d to connect the two through-holes C5W and C6W. A through-hole C4W is formed in the third solid electrolyte layer 13a near the insulating layer 14c. A connecting line PL4W is formed between the two ceramic layers 13a and 14c to connect the two through holes C4W and C5W.The third connecting conductor 13bL is connected to the through-hole C4W on one side of the third solid electrolyte layer 13a opposite the insulating layer 14c. The conductor track CLW passes through the three through-holes C4W, C5W, and C6W. The conductor track CLW allows the electrode contact surface PdW to be used as a contact surface for the inner second pump electrode 13b.

[0081] Next, a conductor track CLSa is described. In the present embodiment, the through-hole C6S of the insulating layer 14d is separated from the one in Fig. The through-hole shown in Figure 3 is offset in the forward direction FWD. For the longitudinal arrangement D1, the through-hole C5S of the insulating layer 14c is positioned between the two through-holes C4S and C6S. A connecting conductor PL5S is formed between the two ceramic layers 14c and 14d to connect the two through-holes C5S and C6S. The conductor track CLSa runs through the three through-holes C4S, C5S, and C6S. The conductor track CLSa allows the electrode contact surface PdS to be used as a contact surface for the counter electrode 13c to the second pump electrode.

[0082] Next, a conductor track CLQa is described. In the present embodiment, the through-hole C3Q of the second solid electrolyte layer 12a is separated from the one in Fig. The through-hole shown in section 3 is offset in the forward direction (FWD). Other configuration features are similar to those of the second conductor track, CLQ, which is shown in Fig. 3 is shown.

[0083] Fig. Figure 7 shows an explanatory diagram illustrating the arrangement of through holes as viewed in the direction of D2 of the lamination. Similar to Fig. 4 contains Fig. 7 a projection view of the NO X -Sensor elements 10A. Filled dots denote in Fig. 7 through holes formed in the insulation layer 14e; double circles denote through holes formed in the insulation layer 14d; and dashed circles denote through holes formed in the interior of the gas sensor element 10A.

[0084] Viewed in the direction of D2 of the lamination, in the present embodiment all through holes are arranged such that they do not overlap, as in Fig. Figure 7 shows that all conductor tracks CLP, CLQa, CLV, CLSa, and CLW pass through through-holes formed in a plurality of layers, each conductor track corresponding to the "Type 1 conductor track" in the claims. Viewed in the direction D2 of the lamination, the through-holes are therefore never arranged on the same straight line parallel to the direction D2 of the lamination (a direction perpendicular to the longitudinal direction D1 and the lateral direction D3). Even if the NO X If sensor element 10A vibrates due to external influences or shocks, then the occurrence of cracks or the like is sufficiently suppressed, thereby increasing the resistance of the NO X -Sensor elements 10A can be maintained to a sufficient degree.

[0085] A multitude of through-holes, through which all of the conductor tracks CLP, CLQa, CLV, CLSa, and CLW pass, also differ from one another in their arrangements along the longitudinal direction D1. Consequently, the resistance of the NO X -Sensor element 10A must be larger than that of the NO X -Sensor element 10, which is in Fig. 4 is shown.

[0086] Among the pairs, each consisting of any two of the four through holes C1P, C1Q, C1R, and C1V formed in the insulation layer 14e, one pair consisting of the two through holes closest to each other is a first pair PR1 (through holes C1V and C1Q). A first distance DT1 is the shortest distance between the through holes C1V and C1Q of the first pair PR1. Among the pairs, each consisting of any two of the four through holes C6S, C6T, C6U, and C6W formed in the insulation layer 14d, one pair consisting of the two through holes closest to each other is a second pair PR2 (through holes C6T and C6U). A second distance DT2 is the shortest distance between the through holes C6T and C6U of the second pair PR2. In the present embodiment, DT1 is smaller than DT2 (DT1 < DT2).Accordingly, of the pairs consisting of any two of the through-holes formed in the insulating layers 14e and 14d, the first pair, consisting of two through-holes arranged closest to each other, is PR1. In the present embodiment, the two through-holes C1Q and C1V forming the first pair PR1 are electrically connected to the different type 1 conductors CLQa and CLV, respectively. Since the two conductors CLQa and CLV, which are arranged closest to each other, are type 1 conductors, the occurrence of cracks or the like originating from two through-holes arranged closest to each other in one of the outermost layers can therefore be suppressed, thus increasing the resistance of the NO. X -Sensor elements 10A can be maintained even if the NO X -Sensor element 10A vibrates due to external influences or shocks.

[0087] Furthermore, a third gap DT3 is in Fig. Figure 7 shows that the third distance DT3 is the shortest distance between the two through-holes C2Q and C2V formed in the first solid electrolyte layer 11a. In the present embodiment, DT3 is larger than DT1 (DT3 > DT1). Because the third distance DT3 is large, leakage currents through the solid electrolyte layer 11a between the two through-holes C2Q and C2V can be suppressed. Furthermore, because the first distance DT1 is short (distance between the two through-holes C1V and C1Q), the two electrode contact surfaces PdQ and PdV can be arranged close to each other. Consequently, the space required for arranging connection terminals in contact with the corresponding electrode contact surfaces PdQ and PdV can be reduced. A combination of two conductor tracks exhibiting these features is not limited to a combination of the two conductor tracks CLQa and CLV, and a combination of two other conductor tracks can exhibit these features.

[0088] Furthermore, position CP1 and the first arrangement area R1 are in Fig. 7. The position CP1 and the first arrangement area R1 are identical in meaning to the position CP1 and the first arrangement area R1, respectively, which are shown in Fig. 5 are shown. As in Fig. Figure 7 shows the position of each of the two through holes C1P and C2P, which are defined for forming the first conductor track CLP in the longitudinal direction D1 within the first arrangement area R1. Accordingly, the NO X -Sensor element 10A of the present embodiment offers various advantages similar to those of the NO X -Sensor element 10 of the first embodiment. C. Third embodiment

[0089] Fig. Figure 8 shows a perspective exploded view of another embodiment of the gas sensor element of the present invention. A perspective view similar to that of Fig. 3 is in Fig. Figure 8 shows a gas sensor element 10d of the present embodiment, which is an air-fuel ratio sensor for measuring an air-fuel ratio. The configuration of this air-fuel ratio sensor is such that the diffusion resistance 15b, the second measuring chamber 18, the insulating layer 14b, the reference oxygen chamber 17, and the second pump cell 13 (13a, 13b, and 13c) are formed from the configuration of the NO X -Sensor element 10, which is in Fig. The section shown in point 2 has been removed.

[0090] In the following description of the present embodiment, as well as in the case of the one described in Fig. In the first embodiment shown in Figure 2, the control unit CU controls the gas sensor element 10B. The control unit CU (see Figure 2) Fig. 2) Controls the electrode-to-electrode voltage (terminal-to-terminal voltage) of the first pump cell 11 so that the electrode-to-electrode voltage (terminal-to-terminal voltage) of the oxygen concentration detection cell 12 adjusts to a predetermined voltage (e.g., 450 mV). If the air-fuel ratio is greater than the theoretical air-fuel ratio (lean), a current flows through the first pump cell 11 in the opposite direction to the direction flow when the air-fuel ratio is less than the theoretical air-fuel ratio (rich). In both cases, the magnitude of the current varies essentially proportionally with the air-fuel ratio. Therefore, the air-fuel ratio can be determined by detecting the magnitude and direction of the current flow through the first pump cell 11.

[0091] Fig. Figure 8 shows a rear end region of the gas sensor element 10B. The gas sensor element 10B differs from the one in Fig. The gas sensor element 10 shown in Figure 3 was modified only by removing the following components: the insulating layer 14b, the third solid electrolyte layer 13a (through hole C4S), the connecting line 13cL, the connecting line 13bL, the through hole C3P, the connecting line PL2P, the through hole C5S, the connecting line PL4S, the through hole C6S, the third conductor track CLS, and the electrode contact surface PdS. Other configuration features are similar to those described in Figure 3. Fig. 3 are shown.

[0092] Even in this embodiment, the first conductor track CLP also exhibits features similar to those of the conductor track CLP of the first embodiment (see Fig. 3) Accordingly, the gas sensor element 10B also has advantages similar to those of the gas sensor element 10 described above. D. Experimental Examples

[0093] Next, the gas sensor element 10 according to the first embodiment of the present invention and a gas sensor element of a comparison example were subjected to a stress test that induces the formation of cracks (fracture of the element). The gas sensor element of the comparison example is configured such that the through-holes C1P, C2P, and C3P of the first conductor track CLP are aligned when viewed in the direction D2 of the lamination. Other configurational features of the gas sensor element of the comparison example are similar to those of the gas sensor element 10 of the first embodiment. The position of the through-hole C1P of the gas sensor element of the comparison example and the position of the through-hole C1P of the gas sensor element 10 of the first embodiment are identical.

[0094] Both the gas sensor element of the first embodiment and of the comparative example were arranged on two axes of rotation (span: 14 mm). The gas sensor elements were arranged such that the following conditions were met: • The outer surface of the insulation layer 14e is in contact with the two pivot points. • The direction connecting the two pivot points coincides with the longitudinal direction D1 of the gas sensor element. • The through holes C1P of the gas sensor elements are located at the midpoint between the two pivot points.

[0095] A compressive load was applied in the direction of insulation layer 14d towards insulation layer 14e to the outer surface of insulation layer 14d of each gas sensor in an area that, when projected in the direction of D2 of the lamination, lies above the through-hole C1P; i.e., in an area corresponding to the midpoint between the two pivot points. The load [N] was increased until the gas sensor elements of the first embodiment and the comparison example fractured. Fourteen pieces each of the gas sensor element of the first embodiment and of the gas sensor element of the comparison example were prepared and subjected to the load test. The results of the measurement are shown in Table 1 and in Fig. 9 shown. [Table 1] Messung Vergleichsbeispiel[N] Ausführungsform [N] 1 98,2 169,2 2 108,5 151,9 3 115,1 170,3 4 120,8 157,1 5 124,0 150,6 6 126,6 163,6 7 127,3 145,2 8 129,7 169,3 9 132,5 167,0 10 133,9 183,2 11 136,6 176,9 12 141,3 139,7 13 144,4 155,1 14 148,8 167,1 Durchschnittswert 127,71 161,9

[0096] Fig. Figure 9 shows the measured values ​​of the samples of the first embodiment and the comparison example, which are represented by “X”. The filled dots denote the average values ​​of the measured values ​​of the first embodiment and the comparison example, respectively. As shown in Table 1 and Fig. As shown in Figure 9, the gas sensor elements of the first embodiment exhibit an average breaking load of approximately 160 N, whereas the gas sensor elements of the comparison example exhibit an average breaking load of approximately 130 N. The experimental results demonstrate that the formation of a conductor track of type 1, as in the case of the first embodiment, suppresses the occurrence of fractures. E. Modifications

[0097] Among the components of the embodiments described above are components that differ from those mentioned in the independent claim; these are additional components and can be omitted if necessary. The present invention is not limited to the embodiments or modes described above, but can be implemented in various other forms without deviating from the basic concept of the invention. The following modifications are possible, for example: (1) In the embodiments described above, penetration holes extending through the corresponding ceramic layers in the direction of the lamination are not limited to through holes but can assume various other forms. For example, via holes can be used for through-hole contacts; that is, penetration holes formed in the corresponding ceramic layers and filled with a conductor. (2) In the embodiments described above, penetration holes may be formed in layers other than the following three types of layers: the solid electrolyte layer, the support layer (a layer for supporting the heat-generating resistor), and the outermost layers (layers in contact with the contact surfaces). Even in this case, a conductor path preferably having a penetration hole formed in the outermost layer and a penetration hole formed in at least one of the solid electrolyte layers and the support layer preferably has the following features to suppress an excessive drop in the resistance of the gas sensor element. In particular, looking towards the lamination direction, a plurality of penetration holes used to form a conductor path and formed in corresponding layers of the three types described above are preferably not arranged one above the other.A conductor track with such features corresponds to the "type 1 conductor track" in the claims.

[0098] The three types of layers mentioned above (the solid electrolyte layers, the support layer, and the outermost layers) can be formed as dense layers with only a small void. By arranging a plurality of penetration holes in corresponding layers of the three types (excluding penetration holes in layers other than the three types of layers), which exhibit the arrangement features of the embodiments discussed in the preceding description, an excessive drop in the resistance of the gas sensor element can therefore be suppressed.

[0099] For example, the positions along the longitudinal direction of a plurality of penetration holes used to form the conductor track of type 1 and formed in corresponding layers of the three types are within the first arrangement area R1 in Fig. 5 or Fig. 7. The positions along the longitudinal direction preferably differ from each other.

[0100] Viewed laterally, penetration holes in each of the three types of layers are preferably not arranged consecutively. Viewed in the direction of lamination, a penetration hole formed in a layer other than the three types of layers may lie above a penetration hole of the conductor path of type 1 formed in one of the three types of layers. However, the arrangement of all penetration holes formed in all layers, including those other than the three types of layers, preferably exhibits the arrangement features discussed in the preceding description of the embodiments. Viewed in the direction of lamination, for example, all penetration holes used to form the conductor path of type 1 are preferably arranged such that they do not overlap any other penetration hole formed in the corresponding layer.

[0101] (3) In the embodiments described in Fig. 3, Fig. 6 and Fig. As shown in Figure 8, all electrode contact surfaces can be formed on the outer surface of the insulating layer 14e. Alternatively, all electrode contact surfaces can be formed on the outer surface of the insulating layer 14d.

[0102] In the Fig. 5 and Fig. In the embodiments shown in Figure 7, penetration holes within the first arrangement area R1 can be configured such that they overlap when viewed in the direction D2 of the lamination. However, to increase the resistance of the gas sensor element, such overlapping penetration holes are preferably not formed within the first arrangement area R1. In the case where a plurality of conductor tracks are formed within the first arrangement area R1, preferably at least one of the conductor tracks is a "type 1 conductor track". In particular, preferably all of the conductor tracks formed within the first arrangement area R1 are type 1 conductor tracks.

[0103] In the embodiments described above, the electrode contact surfaces and the penetration holes can be arranged in various positions. For example, a plurality of penetration holes used to form a common conductor track of type 1 can be arranged along the lateral direction D3. The support layer for carrying the heater can also be arranged between two cells. Furthermore, different materials can be used to form the layers of the gas sensor.

[0104] (4) The configuration of the gas sensor is not limited to the Fig. The one shown is limited and can be used in various configurations. For example, a single component can be used as mounting area 160 to hold the gas sensor element.

[0105] The gas sensor element is not on the NO XThe invention is limited to the air-fuel ratio sensor and the air-fuel ratio sensor, and can be applied to gas sensors for detecting various other gas components and measuring the concentration of such gas components. For example, the invention can be applied to an oxygen concentration sensor for measuring the oxygen concentration.

[0106] The present application relates to a gas sensor comprising a gas sensor element configured by laminating three or more ceramic layers and having an electrode contact surface and penetration holes arranged in an outer surface thereof. These penetration holes extend along a direction of lamination through two or more of the ceramic layers located between an inner conductor and the electrode contact surface. The gas sensor element includes a conductor formed therein, which passes through several of the corresponding ceramic layers and electrically connects the inner conductor to the electrode contact surface. The conductor is furthermore a conductor of type 1, which passes through a plurality of the penetration holes, the penetration holes being arranged such that they do not overlap when viewed in the direction of lamination. Description of the reference symbols: 10, 10A, 10B Gas sensor element 10BE rear end 11 first pump cell 11a first solid electrolyte layer 11b outer first pump electrode 11c inner first pump electrode 11e Protective layer 11bL connecting line 11cL pump electrode line 12 Oxygen concentration detection cell 12a second solid electrolyte layer 12b Detection electrode 12c Reference electrode 12bL detection electrode lead 12cL first connecting line 13 second pump cell 13a third solid electrolyte layer 13b inner second pump electrode 13c Counter electrode to the second pump electrode 13bL third connecting line 13cL second connecting line 14a, 14b, 14c, 14d, 14e insulation layer 15a first diffusion resistance 15b second diffusion resistance 16 first measuring chamber 17 Reference oxygen chamber 18 second measuring chamber 50 heaters 50La, 50Lb connecting cable 106 ceramic cuff 110, 100P-110U connection 138 metallic sleeves 139 Thread area 140 rear end area 142 outer protector 143 inner protector 144 outer tube 146 conductor wire 150 Grommet 151 ceramic holders 152 lead 153, 156 powder layer (talc ring) 154 Through hole 157 Seal 158 metal holders 160 mounting area 161 Wire entry hole 166 Insulation contact part 167 Flange area 168 Contact insertion hole 169 Mounting part 200 gas sensor PL1P, PL2P first connection line PL1Q, PL2Q second connecting line PL4S, PL1Q, PL2Q, PL1V, PL5W, PL4W, PL5S connecting cable CLSa conductor track CLQa Type 1 conductor D1 Longitudinal direction D2 direction of lamination D3 lateral direction R1 first arrangement area R2 second arrangement area GM, GN gas to be measured CU control unit C1P, C1Q, C1R, C1V, C2P, C2Q, C3P, C2V, C3Q, C4S, C4W, C5S, C5W, C6S, C6T, C6U, C6W Through hole PR1 first pair PR2 second pair DT1 first gap DT2 second gap DT3 third gap BWD Reverse Direction FWD forward direction CLP, CLQ, CLQa, CLS, CLSa, CLV, CLW conductor track PdP, PdQ, PdR, PdS, PdU, PdV, PdW electrode contact area

Claims

[1] Gas sensor, comprising: a gas sensor element (10, 10A, 10B) having the form of a plate extending in a longitudinal direction (D1) and configured by lamination of three or more ceramic layers, wherein the gas sensor element (10, 10A, 10B) has an electrode contact surface (PdP to PdW) arranged on an outer surface of the gas sensor element (10, 10A, 10B) and penetration holes (C1P to C6W) extending in a direction (D2) of the lamination through two or more of the corresponding ceramic layers arranged between an inner conductor provided in the gas sensor (10, 10A, 10B) and the electrode contact surfaces (PdP to PdW), wherein the gas sensor element (10, 10A, 10B) has a conductor track (CLP to CLW) formed therein such that the conductor track (CLP to CLW) passes through the penetration holes (C1P to C6W) formed in various of the corresponding ceramic layers and electrically connects the inner conductor and the electrode contact surface (PdP to PdW), and The conductor track (CLP to CLW) comprises a conductor track of type 1 (CLP; CLP to CLW; CLP) which passes through a plurality of penetration holes (C1P to C6W) which, viewed in the direction (D2) of the lamination, are arranged in a non-overlapping manner, wherein, viewed in the direction (D2) of the lamination, a plurality of penetration holes (C1P to C6W) through which the conductor track of type 1 (CLP; CLP to CLW; CLP) passes are arranged at least longitudinally (D1) offset from one another, such that the penetration holes (C1P to C6W) arranged at least longitudinally (D1) offset from one another are electrically connected to each other. [2] Gas sensor according to claim 1, further comprising: a terminal (110) in contact with the electrode contact surface (PdP to PdW) and configured to connect the electrode contact surface (PdP to PdW) to an external circuit, and a mounting area (160) for holding the gas sensor element (10, 10A, 10B), wherein the conductor track of type 1 (CLP; CLP to CLW; CLP) is arranged within an arrangement area (R1) between a contact position (CP1) in which the terminal (110) is in contact with the electrode contact surface (PdP to PdW) and a mounting position in which the mounting area (160) holds the gas sensor element (10, 10A, 10B). [3] Gas sensor according to claim 1 or 2, wherein the gas sensor element (10, 10A, 10B) comprises a plurality of electrode contact surfaces (PdP to PdW) and an outermost layer (14d, 14e) which serves as the outer surface thereof and is in contact with the plurality of electrode contact surfaces (PdP to PdW); the outermost layer (14d, 14e) has a large number of penetration holes (C1P to C6W) formed therein; and a pair consisting of two penetration holes (C1Q, C1V) of any two penetration holes (C1P to C6W) formed in the outermost layer, which is used to form two conductor tracks (CLQa, CLV) passing through the corresponding penetration holes (C1Q, C1V), and wherein each of the conductor tracks (CLQa, CLV) is a conductor track of type 1 (CLP; CLP to CLW; CLP), wherein the pair consisting of two penetration holes (C1Q, C1V) consists of two penetration holes (C1Q, C1V) that are closest to each other. [4] Gas sensor according to claim 3, wherein all conductor tracks (CLP to CLW) passing through a plurality of corresponding penetration holes (C1P to C6W) formed in the outermost layer (14d, 14e) are of type 1 (CLP in Fig. 3, CLP to CLW in Fig. 7, CLP in Fig. 8) are. [5] Gas sensor according to claim 3 or 4, wherein the number of penetration holes (C1P to C6W) occurring in each ceramic layer is at most one when an imaginary section of the gas sensor element (10, 10A, 10b) is considered perpendicular to the longitudinal direction (D1). [6] Gas sensor according to any one of claims 3 to 5, wherein: the outermost layer (14d, 14e) comprises aluminium oxide as the main component; the gas sensor element (10, 10A, 10B) further comprises a solid electrolyte layer (11a, 12a, 13a); and the distance (DT1) between the two (C1Q and C1V) of the plurality of penetration holes (C1P to C6W) formed in the individual outermost layers (14d, 14e) is shorter than a distance (DT3) between two penetration holes (C2Q, C2V) formed in the solid electrolyte layer (11a, 12a, 13a) through which the two corresponding type 1 conductors (CLQa, CLV) pass through the outermost layer (14d, 14e). [7] Gas sensor according to claim 6, wherein the inner conductor is at least one consisting of a heat-generating resistor (50) for heating the gas sensor element (10, 10A, 10B) and a pair of electrodes (11b, 11c, 12b, 12c, 13b, 13c) provided on the solid electrolyte layer (11a, 12a, 13a) which partially form a cell. [8] Gas sensor according to any one of claims 1 to 5, wherein the gas sensor element (10, 10A, 10B) further comprises a solid electrolyte layer (11a, 12a, 13a), and wherein the inner conductor is at least one consisting of a heat-generating resistor (50) for heating the gas sensor element (10, 10A, 10B) and a pair of electrodes provided on the solid electrolyte layer (11a, 12a, 13a), which partially form a cell.

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