JP4631926B2 - Gas sensor - Google Patents

Description

  The present invention relates to a gas sensor installed in an exhaust system of an internal combustion engine and used for combustion control and the like.

  A gas sensor having the following configuration is known as a gas sensor installed in an exhaust system of an automobile engine and used for engine combustion control. This gas sensor includes a cylindrical housing, a gas sensor element inserted through the housing, an atmosphere-side cover that covers the base end side of the housing, and a measured gas-side cover that covers the distal end side of the housing.

  The tip of the gas sensor element is housed in the measured gas side cover and is exposed to the measured gas here. The atmosphere side cover covers the base end side of the gas sensor element, and an output terminal and the like drawn out from the gas sensor element are housed inside.

  Various sealing materials, insulating materials, packings, and the like are disposed between the gas sensor element and the housing, and the two are hermetically sealed. At this location, the measured gas side atmosphere in the measured gas side cover and the atmospheric side atmosphere in the atmospheric side cover are separated, and the measured gas is prevented from entering the atmospheric side atmosphere. When the gas to be measured enters the atmosphere on the atmosphere side, the measurement accuracy of the gas concentration is lowered. Therefore, the higher the airtightness between the gas sensor element and the housing, the better.

  However, liquid components, such as gasoline, contained in the gas to be measured may cause fine gaps, etc. existing in the interior and boundaries of various sealing materials, insulating materials, packings, etc. disposed between the gas sensor element and the housing. It may penetrate into the atmosphere in a liquid or gaseous state. Such intrusion of liquid components also causes a reduction in gas sensor measurement accuracy.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a gas sensor in which an exhaust gas component, particularly a liquid component such as gasoline, is difficult to enter between a housing and a gas sensor element.

  Therefore, as a result of earnest research, we found the following problems and derived the present invention. That is, when there are many fine particles outside the specific range described below, when the filler is formed by pressurizing the powder filler, a large amount of air is caught between the particles. The specific gravity cannot be increased. On the other hand, when there are many coarse particles outside the above specific range, the coarse particles are not easily broken down, and the particles forming the filling portion are not uniformly loaded, so that the specific gravity does not partially increase. For this reason, the formation of the filling portion requires a high molding pressure, which may cause problems such as cracking of the gas sensor element.

  The present invention includes a housing and a gas sensor element inserted and disposed in the housing, and at least a portion between the housing and the gas sensor element is filled with a powder filler formed by adding a filling auxiliary material. The gas sensor is hermetically sealed by the filled portion.

  In the filling part of the gas sensor in the present invention, a filling auxiliary material is added to the powder filling material constituting the filling part. For this reason, the filling auxiliary material can fill the gaps between the powder fillers in the filling part and the contact surface between the particles, further increasing the density of the filling part, improving the adhesion between the particles, and high sealing. Sex can be obtained. Furthermore, since the gap between the powder fillers in the filling portion is filled with the filling auxiliary material, it is difficult for liquid components to enter due to capillary action.

The present invention has a housing and a gas sensor element inserted and disposed in the housing, and at least a portion between the housing and the gas sensor element is added with a filling auxiliary material made of a first aluminum phosphate aqueous solution. comprising Te powder filler is hermetically sealed by the filling unit filled, above the surface of the gas sensing element, the porous material uneven layer formed of any one or more of the electrode protective layer is formed The proximal end of the concavo-convex layer and the electrode protection layer is the same as the proximal end of the filling portion, or is closer to the distal end than the proximal end of the filling portion. It is a gas sensor characterized by this.

  In the gas sensor according to the present invention, an uneven layer and an electrode protective layer are formed on the surface of the gas sensor element. The surface of the concavo-convex layer is uneven, and when the filling portion is formed between the gas sensor element and the housing, the powder filler cannot completely fill the concavo-convex on the surface of the concavo-convex layer, and the filling portion A gap or a maze structure may be formed between the layers. In addition, the concavo-convex layer itself may have a gap, and the liquid component may enter due to a capillary phenomenon that passes through the gap existing in the concavo-convex layer.

  The electrode protective layer also has an uneven surface similar to the uneven layer, and when the filling portion is formed between the gas sensor element and the housing, the powder filler completely fills the unevenness on the surface of the electrode protective layer. In some cases, a gap or a maze structure may be formed between the filling portion and the electrode protective layer. In addition, as described later, the electrode protective layer is required to be capable of sufficiently diffusing a specific gas to be detected or a gas to be measured to the electrode, so that the electrode protective layer is made of a porous material having many gaps and micropores. There are many cases. Therefore, the liquid component may invade due to the capillary phenomenon that passes through the gaps or micropores in the electrode protective layer.

  In the present invention, a gap is formed between the gas sensor element and the filling portion, or the concavo-convex layer having gaps or micropores, and the end portion on the base end side of the electrode protective layer is more than the end portion on the base end side of the filling portion. Is also on the tip side. For this reason, the liquid component which infiltrated via the uneven | corrugated layer on the surface of a gas sensor element or between an electrode protective layer and a filling part can be cut off in the location where the filling part, an uneven | corrugated layer, and an electrode protective layer are not contacting. Therefore, high sealing performance can be obtained with the gas sensor according to the present invention.

  The present invention includes a housing and a gas sensor element inserted and disposed in the housing, and at least a part between the housing and the gas sensor element is hermetically sealed by a filling portion filled with a powder filler. The powder filler is a gas sensor characterized in that fine particles and coarse particles are removed by classification before filling.

The gas sensor according to the present invention removes extremely fine particles and extremely coarse particles by classification, so that the load applied when forming the filling portion can be uniformly applied to the entire powder filler particles. Particles collapse uniformly and can be filled between the particles. Furthermore, since a labyrinth structure having almost no gap is formed uniformly throughout the entire filling portion, the permeation path of the filling portion from the measured gas side to the base end side becomes long, so that a sufficient labyrinth structure can be obtained with a low load. Obtainable. In addition, since the filling portion can be formed with a low load, there is no possibility that the gas sensor element will be cracked, chipped, cracked or otherwise damaged. Therefore, the liquid monomer component is difficult to penetrate, it is possible to obtain a gas sensor having a filling unit having a high sealing property.

  The present invention includes a housing and a gas sensor element inserted and disposed in the housing, and at least a portion between the housing and the gas sensor element is filled with a powder filler formed by adding a filling auxiliary material. The above powder filler is in a state in which particles having a particle size of 80 to 5000 μm occupy 80% by weight or more of the total weight of the powder filler before filling. This is a featured gas sensor.

  The present invention includes a housing and a gas sensor element inserted and disposed in the housing, and at least a part between the housing and the gas sensor element is hermetically sealed by a filling portion filled with a powder filler. The powder filler is in a state in which particles having a particle size of 80 to 5000 μm account for 80% by weight or more of the total weight of the powder filler before filling, and the surface of the gas sensor element is uneven. One or more of a layer and an electrode protection layer are formed, and the end portion on the base end side of the uneven layer and the electrode protection layer is the same as the end portion on the base end side of the filling portion, or the above It is a gas sensor characterized in that it is on the distal end side with respect to the end portion on the proximal end side of the filling portion.

  The present invention includes a housing and a gas sensor element inserted and disposed in the housing, and at least a portion between the housing and the gas sensor element is filled with a powder filler formed by adding a filling auxiliary material. The surface of the gas sensor element is formed with at least one of a concavo-convex layer and an electrode protective layer on the surface of the gas sensor element. The gas sensor is characterized in that the end portion is the same as the end portion on the proximal end side of the filling portion or on the distal end side with respect to the end portion on the proximal end side of the filling portion.

  The present invention includes a housing and a gas sensor element inserted and disposed in the housing, and at least a portion between the housing and the gas sensor element is filled with a powder filler formed by adding a filling auxiliary material. The above-mentioned powder filler is in a state where particles having a particle size of 80 to 5000 μm occupy 80% by weight or more of the total weight of the powder filler before filling. One or more of a concavo-convex layer and an electrode protective layer is formed on the surface of the gas sensor element, and the base end side end of the concavo-convex layer and the electrode protective layer is located on the base end side of the filling portion. The gas sensor is characterized in that it is the same as the end portion or at the tip end side from the end portion on the base end side of the filling portion.

  The present invention includes a housing and a gas sensor element inserted and disposed in the housing, and at least a portion between the housing and the gas sensor element is filled with a powder filler formed by adding a filling auxiliary material. The gas sensor is hermetically sealed by a filled portion, and the powder filler is characterized by removing fine particles and coarse particles by classification before filling.

  The present invention includes a housing and a gas sensor element inserted and disposed in the housing, and at least a part between the housing and the gas sensor element is hermetically sealed by a filling portion filled with a powder filler. Before the filling, the powder filler removes fine particles and coarse particles by classification, and on the surface of the gas sensor element, one or more of an uneven layer and an electrode protective layer are formed. A base end side end portion of the uneven layer and the electrode protection layer is the same as a base end side end portion of the filling portion or a tip end side of the base end side end portion of the filling portion. It is a gas sensor.

  The present invention includes a housing and a gas sensor element inserted and disposed in the housing, and at least a portion between the housing and the gas sensor element is filled with a powder filler formed by adding a filling auxiliary material. The powder filling material removes fine particles and coarse particles by classification before filling, and either one of an uneven layer and an electrode protective layer is formed on the surface of the gas sensor element. The above is formed, and the end portion on the base end side of the concavo-convex layer and the electrode protective layer is the same as the end portion on the base end side of the filling portion, or from the end portion on the base end side of the filling portion. It is a gas sensor characterized by being at the tip side.

  In the present invention, the filling portion is composed of a powder filler composed of large-diameter particles in the above-mentioned range, a filling auxiliary material is added to the powder filler, and the end portion on the base end side of the uneven layer and the electrode protective layer is The exhaust gas component between the housing and the gas sensor element is characterized by removing extremely fine particles and coarse particles on the tip side of the base end side of the filling portion by classification, and from the above-mentioned effects. In particular, it is possible to provide a gas sensor in which liquid components such as gasoline are difficult to enter.

  In the present invention, when particles having a particle size in the range of 80 to 5000 μm are less than 80% by weight of the entire powder filler, the particle size of the particles constituting the powder filler is too fine, Since the amount of air contained is large, it is difficult to increase the density at the time of filling, and there is a possibility that it is difficult to obtain a filled portion having high airtightness. Further, a more preferable powder filler is a powder filler in which more particles are present in a range of 80 to 5000 μm, and most preferable is a powder filler in which all particles are within the above range.

  Further, in the above powder filler, when there are many powders having a particle size of less than 80 μm, the amount of air remaining in the filling portion increases when the powder filler is formed into a filling portion, and the filling portion There is a possibility that the problem that the sealability of the filling portion cannot be secured because the specific gravity of the filler does not increase.

  Further, in the above powder filler, when forming a filling portion by pressurizing and filling, a gap between relatively coarse particles is filled while a part of the powder filler particles collapses. If the powder filler has a particle size exceeding 5000 μm, a high pressure is required due to the formation of the filling portion, the gas sensor element is cracked, and other members (for example, the insulator in the gas sensor of the first embodiment has an insulator or the like). Damage or deterioration) may occur.

  Gas sensor classification methods include dry sieve classification, wet sieve classification, gravity dry classification using airflow, centrifugal dry classification, rotary dry classification, sedimentation wet classification using liquid, and mechanical wet classification. Centrifugal wet classification can be used.

  Moreover, the gas sensor element in each gas sensor of this invention is demonstrated. The gas sensor element includes a solid electrolyte body and a pair of electrodes provided on the solid electrolyte body. The gas sensor element is configured such that one of the electrodes is in contact with the measured gas side atmosphere containing the specific gas to be measured, and the other is in contact with the atmosphere side atmosphere serving as the reference gas. A gas sensor atmosphere and an atmosphere atmosphere exist inside the gas sensor, and the filling portion separates the atmosphere atmosphere and the gas atmosphere to be measured.

  As a gas sensor element in each gas sensor of the present invention, an element having a configuration in which a pair of electrodes are provided on the outer side surface and the inner side surface of a cup-type solid electrolyte body can be used. Alternatively, an element in which an electrode is provided on a plate-shaped solid electrolyte body and the solid electrolyte plate and an insulating plate are appropriately laminated can be used.

  In addition, there is a configuration in which the housing and the gas sensor element are hermetically sealed only by the filling portion. However, the housing and the gas sensor element are combined with another filling material such as a glass sealing material and the filling portion. In some cases, a structure that ensures higher sealing performance between the two is employed. Needless to say, the present invention can also be applied to gas sensors having other shapes, for example, stacked gas sensor elements, and the same effects can be obtained.

  The gas sensor element includes an element for measuring the oxygen concentration in the gas to be measured, an element for measuring the air-fuel ratio, etc. when the gas sensor is installed in the exhaust system of an automobile engine, NOx in the gas to be measured, An element for measuring CO, HC, or the like can be used.

  Moreover, it is preferable that the said powder filler is in the state which the particle | grains whose particle size is 100-1000 micrometers occupies 80 weight% or more of the whole powder filler before filling. By using such a powder filler, the specific gravity of the filling portion becomes higher and a filling portion having high sealing properties can be obtained.

  In the above powder filler, when there are many particles having a particle size of less than 100 μm, the amount of air remaining in the filling portion increases, and the specific gravity of the filling portion is hardly increased. There is a risk that sufficient sex cannot be secured.

  In addition, when there are many particles with a particle size exceeding 1000 μm, the particles are large, so the filling state of the filling part tends to vary, making it difficult to sufficiently apply the load when filling the powder filler. There is a possibility that the sealing performance of the part is slightly impaired.

  Moreover, it is preferable that the said powder filler is in the state which the particle | grains whose particle size is 125-710 micrometers occupies 80 weight% or more of the whole powder filler before filling. As a result, by using a relatively large diameter powder filler, the amount of air remaining in the powder filler particles can be almost eliminated, and when a filling portion is formed by applying a load to the powder filler. In addition, the amount of air caught in the filling portion can be almost eliminated.

  Furthermore, by reducing the number of extremely coarse particles larger than the particle size of 710 μm, the load when forming the filling portion can be uniformly applied to the entire powder filling particles, so that the specific gravity of the filling portion is increased uniformly. And high sealing performance can be obtained stably. Furthermore, since the load is uniformly applied to the powder filler, the specific gravity of the filled portion can be increased with a relatively low load.

  In the invention, it is preferable that fine particles are removed from the powder filler by classification before filling until particles having a particle size of less than 80 μm occupy 10% by weight or less of the entire powder filler. As a result, the number of fine particles existing in the gaps between the particles is reduced when the filler is formed because extremely fine particles are reduced, and the adhesion between the particles of the filler is improved. Since there are fewer parts filled with fine particles, a labyrinth structure with almost no gaps is formed throughout the entire filling part, so that the permeation path through which liquid components such as exhaust gas components and gasoline enter penetrates and has high sealing performance. Can be obtained.

  Moreover, it is preferable that fine particles are removed from the powder filler by classification before filling until particles having a particle size of less than 100 μm occupy 10% by weight or less of the entire powder filler. As a result, the number of extremely fine particles is extremely reduced. Therefore, when the filling portion is formed, the fine particles present in the gaps between the particles are further reduced, and the adhesion between the particles of the filler is improved. In addition, since there are fewer portions where fine particles are locally filled between particles, a labyrinth structure with almost no gaps is formed, so that the permeation path through which liquid components such as exhaust gas components and gasoline enter can be further extended. In addition, it becomes difficult to penetrate and a high sealing performance of the filling portion can be secured.

  Moreover, it is preferable that fine particles are removed from the powder filler by classification before filling until particles having a particle size of less than 125 μm occupy 10% by weight or less of the entire powder filler. As a result, there are almost no extremely fine particles, and when the filling portion is formed, there are almost no fine particles present in the gaps between the particles, and the adhesion between the filler particles is improved.

  In addition, since there are almost no portions where fine particles are locally filled between the particles, a labyrinth structure having almost no gap formed in the filling portion is formed over the entire filling portion, and relatively coarse particles are broken by the load. Since the contact surfaces of the particles are more closely contacted for filling, the amount of the gap is also reduced. Therefore, the gap from which the exhaust gas component and liquid components such as gasoline enter from the exhaust side to the atmosphere side becomes longer and the amount of the gap becomes smaller, so that high sealing performance can be stably obtained. .

  In addition, it is preferable that coarse particles are removed from the powder filler by classification before filling until particles having a particle size of 5000 μm or more occupy 10% by weight or less of the entire powder filler. As a result, a high molding pressure is required to fill the gaps between the particles by applying sufficient loads of coarse particles when forming the filling part, but the gas sensor element is cracked, chipped, cracked, or other Since a labyrinth structure having almost no gap is obtained by coarse particles without causing damage or deterioration of the member, high sealing performance can be obtained. Therefore, it is possible to obtain a gas sensor having a filling portion that is difficult for liquid components to permeate and has high sealing properties.

  In addition, the powder filler is preferably classified before classification until coarse particles having a particle diameter of 1000 μm or more account for 10% by weight or less of the entire powder filler. As a result, when forming the filling part, there is almost no part where extremely coarse particles are partially collected, so that the coarse particles are broken down and the gaps between the filler particles are filled without applying high molding pressure. can do. Therefore, since a maze structure with almost no gap can be formed over the entire filling portion, high sealing performance can be obtained.

  In addition, it is preferable that coarse particles are removed from the powder filler by classification before filling until particles having a particle size of 710 μm or more occupy 10% by weight or less of the entire powder filler. As a result, when forming the filling portion, since there are almost no coarse particles, the filling portion can be formed with a low load, and the difference in particle size between the coarse particles and the fine particles when forming the filling portion is small. Since a load is applied to relatively fine particles that have entered relatively coarse particles, a labyrinth structure having almost no gap can be formed over the entire filling portion, so that liquid components such as exhaust gas components and gasoline can be formed. The permeation path through which the water penetrates becomes longer, and a high sealing performance can be obtained stably.

  Moreover, it is preferable that the axial direction length of the filling part formed between the said housing and the said gas sensor element is 1.5-15 mm. As a result, a filling portion having a high filling property is obtained between the housing and the gas sensor element, and a gas sensor in which liquid components are difficult to enter from the filling portion, the interface between the gas sensor element and the filling portion, and the interface between the housing and the filling portion is obtained. be able to.

  If the axial length of the filling portion is less than 1.5 mm, the strength of the filling portion will be insufficient, and if thermal stress is applied to the filling portion due to the temperature difference during actual use of the sensor, cracks will occur in the filling portion. There is a risk of entering easily. In this case, the liquid component may enter the filling portion.

  When the axial length of the filling portion is larger than 15 mm, there is a possibility that resistance due to friction may increase at the interface between the filling portion and the gas sensor element and at the interface between the filling portion and the housing. Therefore, when the powder filler is pressed to form the filling portion, it is difficult to apply a uniform load to the filling portion, and there is a possibility that variations in specific gravity are likely to occur. In this case, the liquid component may enter from the portion where the specific gravity of the filling portion has not increased.

  Here, the axial length of the filling portion is a distance between an end on the leading end side of the filling portion and an end on the proximal end side of the filling portion, as shown in FIG. 2 described later, and is parallel to the axial direction of the gas sensor element. The length along. When the end on the front end side and the end on the base end side are uneven in the radial direction, the end on the base end side of the filling portion 14 in the outer peripheral portion of the gas sensor element 2 where the filling portion 14 and the uneven layer 203 are in contact with each other The axial length at the position of the outer peripheral portion where the axial distance from the end on the base end side of the uneven layer 203 or the end on the base end side of the electrode protective layer 205 is the shortest is employed.

  The powder filler preferably contains 50% by weight or more of at least one of talc and boron nitride. By using the above-mentioned materials, a structure in which the scaly particles are packed in layers is formed in the packed part, so that a higher specific gravity is obtained than when spherical particles are packed, and exhaust gas components, particularly A liquid component such as gasoline adheres, and a permeation path that penetrates through a minute gap and reaches the base end side is reduced, and high sealing performance can be obtained.

  In addition, since the particles are similarly filled in layers at the filling portion-gas sensor element interface and the filling portion-housing interface, the same effect as the inside of the filling portion can be obtained. In particular, talc powder is a lamellar compound of scaly particles that cleaves in the laminar direction when pressed, and does not destroy the lamellar structure of the talc scaly particles. Since the scale particles collapse and fill the filling portion so as to fill the surface, the specific gravity increases and a filling portion with high sealing properties can be obtained.

  When one or more of talc and boron nitride is less than 50% by weight, a structure in which scale-like particles are packed in layers is not formed in the filled part, and gasoline or the like is partially formed. There is a possibility that a fine gap that allows the liquid component to permeate through remains and high sealing performance cannot be obtained.

  In the gas sensor according to the present invention, the powder filler may be added with other materials as well as the filling auxiliary material. For example, when a small amount of alumina powder is added and alumina powder or the like enters the gap formed by the particles of the powder filler, the gap through which liquid components such as gasoline penetrate can be reduced. In addition, spinel, zirconia, titania, silica, etc. may be added.

  Moreover, it is preferable that the said filling auxiliary material consists of inorganic compound aqueous solution which is liquid at room temperature (20 degreeC). As a result, when forming the filling portion, even if the gap formed between the powder filler powders is a slight gap, the filling auxiliary material is in a liquid state, so that it is efficiently filled. High density can be realized and high sealing performance can be obtained.

  In the present invention, the inorganic compound aqueous solution is preferably composed of at least one of a first aluminum phosphate aqueous solution, a sodium silicate aqueous solution, and a potassium silicate aqueous solution. Thereby, a liquid compound enters the gaps of the powder filler during pressurization, and the density of the filling portion is further increased to obtain a high-density filling portion. More preferably, the filling auxiliary material includes at least a first aluminum phosphate aqueous solution. As a result, even if moisture is absorbed by the powder filler, the liquid state is maintained because the first aluminum phosphate itself is a liquid, and the powder filler can enter the gap of the powder filler.

  Moreover, in this invention, when the said filling auxiliary material consists of inorganic compound aqueous solution which is liquid at room temperature (20 degreeC), the addition amount of the said filling auxiliary material with respect to 100 weight part of said powder fillers is 0.1-10 weight. Part. Thereby, a high-density filling part can be obtained. Moreover, when the filling auxiliary material is less than 0.1 part by weight, the amount does not reach an amount sufficient to fill the gap between the powder fillers, so that it is difficult to obtain a high-density filling part. On the other hand, if the amount exceeds 10 parts by weight, the amount of the filling auxiliary material becomes excessive, which impedes the filling property of the powder filling material and the specific gravity of the filling portion cannot be increased, and the sealing performance of the filling portion may be lowered. is there.

  In the present invention, the filling auxiliary material is preferably made of a liquid inorganic compound in an environment at a temperature of 600 ° C. or lower. As a result, the filling auxiliary material is introduced into the gap between the particles of the powder filling material, and the filling auxiliary material is liquefied during or after the filling portion is formed between the housing and the gas sensor element. The gap between the particles of the material can be filled with the filling auxiliary material, and a high sealing performance of the filling portion can be obtained.

  In the present invention, the inorganic compound includes barium hydroxide, borosilicate glass, aluminosilicate glass, soda lime silicate glass, lead silicate glass, low melting point borate glass, lime alumino glass, It is preferable to consist of any one or more of aluminate glass. These materials can be liquefied at a relatively low temperature. Therefore, heating when filling the filling portion, liquefying the filling auxiliary material, and filling the gaps between the particles of the powder filling material does not exceed the heat resistance of the parts constituting the gas sensor such as the housing and the gas sensor element. . As a result, the permeation path through which the exhaust gas components in the filling portion, particularly liquid components such as gasoline contained in the exhaust gas penetrate, can be closed, and high sealing performance of the filling portion can be obtained.

  Moreover, when the said filling auxiliary material consists of a liquid inorganic compound in the temperature of 600 degrees C or less, it is preferable that the addition amount of the said filling auxiliary material with respect to 100 weight part of said powder fillers is 0.5-30 weight part. . Thereby, a high-density filling part can be obtained. When the amount of the filling auxiliary material is less than 0.5 parts by weight, the amount does not reach an amount sufficient to close the gap between the powder fillers, so that the exhaust gas component, particularly the liquid component such as gasoline contained in the exhaust gas, There is a possibility that the permeation path that penetrates cannot be sufficiently blocked. When the amount of the filling auxiliary material is more than 30 parts by weight, the filling auxiliary material enters excessively into the gap of the powder filling material when forming the filling portion, which greatly impairs the filling property of the powder filling material, There may be more gaps. Therefore, even if the filling auxiliary material is liquefied, the filling portion cannot be sufficiently closed, and there is a possibility that an excellent sealing property cannot be obtained.

  In the gas sensor according to the present invention, at least one of an uneven layer and an electrode protective layer is formed on the surface of the gas sensor element. The uneven layer is provided on the surface of the solid electrolyte body constituting the gas sensor element, and the electrode protective layer is provided so as to cover the electrode provided on the surface of the solid electrolyte body. The uneven layer is provided to improve the adhesion between the electrode and the electrode protective layer, and the electrode protective layer is provided to protect the electrode from poisonous substances in the measurement gas. Note that the electrode protective layer must be made of a porous material in order for the electrode to contact the gas to be measured through the electrode protective layer. Furthermore, only the concave / convex layer, only the electrode protective layer, or both can be provided for the gas sensor element.

  In the present invention, either the base end side end of the concavo-convex layer or the base end side end of the electrode protection layer is 0.5 mm or more from the base end side end of the filling portion to the front end side. Preferably there is. Filling because the edges of the uneven layer and the electrode protective layer meet the above requirements, the permeation path through which liquid components such as gasoline contained in the exhaust gas component, especially gasoline, penetrate in a short time is cut off. The sealability of the part is improved. If it is less than 0.5 mm, the portion that takes a long time for the liquid component to permeate is shortened, so that the margin of sealing performance of the filling portion may be reduced.

  Further, the lower limit is 0 mm, and if it is lower than this lower limit, the liquid component may permeate in a short time from the interface between the concavo-convex layer or the electrode protective layer and the filling portion, and the sealing property of the filling portion may not be ensured.

  In addition, the base end side of either the concavo-convex layer or the electrode protective layer is the same as the tip end side of the filling portion, or closer to the tip end side than the tip end side of the filling portion. Preferably there is. This eliminates the permeation path through which the exhaust gas components, especially liquid components such as gasoline contained in the exhaust gas components, permeate in a short time from the interface between the filling portion and the gas sensor element, thereby greatly improving the sealing performance of the filling portion. To do.

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1) As shown in FIGS. 1 and 2, the gas sensor 1 of the present embodiment has a housing 10 and a gas sensor element 2 inserted and disposed in the housing 10, and the housing 10 and the gas sensor element 2 are arranged. Is hermetically sealed by a filling portion 14 filled with a powder filler. The powder filler is in a state in which particles having a particle size of 80 to 1000 μm account for 80% by weight or more of the total weight before filling.

  This will be described in detail below. The gas sensor of this example is an air-fuel ratio sensor that is installed in the exhaust system of an automobile engine and is used for engine combustion control. As shown in FIG. 1, the gas sensor element 2 is inserted into a metallic, cylindrical housing 10, and a measured gas side cover 11 is provided at the distal end side of the housing 10 and an atmospheric side cover 12 is provided at the proximal end side. It is. The measured gas side cover 11 has a double structure consisting of an inner cover 111 and an outer cover 112, and both are provided with introduction holes 119 for introducing a measured gas. A measured gas enters the measured gas side cover 11 from the outside through the introduction hole 119, and the measured gas side atmosphere 110 is formed in the cover.

  An outer cover 121 is provided on the base end side of the atmosphere-side cover 12 via a water-repellent filter 122, and an atmosphere introduction hole 129 is provided at a position facing the water-repellent filter 122 in the atmosphere-side cover 12 and the outer cover 121. . Air enters the atmosphere-side cover 12 from the outside through the introduction hole 129 and forms the atmosphere-side atmosphere 120.

  The gas sensor element 2 includes a cup-shaped solid electrolyte body 20 and a pair of outer electrodes and inner electrodes provided on the outer and inner surfaces of the solid electrolyte body 20 (not shown). An air chamber 200 is provided inside the solid electrolyte body 20, and the air chamber 200 communicates with the air atmosphere 120. The surface of the solid electrolyte body 20 is an uneven layer 203 (see FIG. 2). Further, a diffusion resistance layer, an electrode protection layer 205, and the like are provided so as to cover an outer electrode (not shown) provided on the solid electrolyte body 20.

  The outer surface of the solid electrolyte body 20 of the gas sensor element 2 is provided with a convex portion 201 projecting radially outward, and the convex portion is opposed to the receiving portion 101 projecting radially inward from the inner side surface of the housing 10. 201 is supported. A metal packing 13 is disposed between the leading end side of the convex portion 201 and the receiving portion 101. A filling portion 14 made of a powder filler containing a filling auxiliary material and an insulator 15 are arranged on the base end side of the convex portion 201, and the end face on the base end side of the insulator 15 has a metal ring 161 for caulking. And is caulked by the end portion 102 on the proximal end side of the housing 10.

  In addition, a connection fitting 212 for connecting the terminal 211 drawn from the gas sensor element 2 to the lead wire 213 drawn to the outside of the gas sensor is disposed inside the atmosphere side cover 12. Reference numeral 221 denotes an atmosphere side insulator, 222 denotes an elastic insulating member, and 29 denotes a heater.

The powder filler is made of talc. Here, talc is a kind of clay mineral, which is a natural material mainly composed of Mg ₃ Si ₄ O ₁₀ (OH) ₂ , and powder having a particle size of 80 to 1000 μm accounts for 80% by weight or more of the total weight. Is in a state of being.

  The filling portion 14 according to this example is manufactured in the following manner. That is, the filling unit 14 puts the metal packing 13 and the gas sensor element 2 in the housing 10 and preliminarily forms a powder filler made of talc into a ring shape, and then supplies the load into the housing 10 and applies a load. After fixing, the insulator 15 and the caulking metal ring 161 are inserted and caulked by the end portion 102 on the proximal end side of the housing 10.

  In order to improve the productivity of talc powder, it can be formed into a ring shape in advance and then introduced into the housing. In this case, in order to give the talc a shape-retaining property, the talc powder is humidified by adding an appropriate amount of water as necessary, and the talc powder is supplied to the ring-shaped mold. And it shape | molds in a ring shape using a press molding machine. The humidified water is dried as necessary after being preformed in a ring shape or assembled to the housing 10. Further, talc can be supplied into the housing 10 directly in the housing 10 while the talc is in powder form.

  Further, the talc as the powder filler is mixed with the primary aluminum phosphate as the filling auxiliary material as follows. Weigh talc, weigh the filling aid to be converted, and convert the filling aid to talc. Next, after the talc particles are uniformly mixed with a rotary mixer or the like, the filling portion 14 is manufactured as described above.

  As shown in FIG. 2, an uneven layer 203 is formed on the surface of the solid electrolyte body 20 of the gas sensor element 2 of this example from the front end side to the base end side of the gas sensor element 2 (not shown). An outer electrode (not shown) is provided so as to cover the uneven layer 203.

  Further, the axial length L of the filling portion 14 and the axial length M of the uneven layer 203 are defined as follows. Of the outer peripheral portion of the gas sensor element 2 where the filling portion 14 and the concavo-convex layer 203 are in contact, the filling portion 14 in a portion where the distance between the base end side end of the filling portion 14 and the base end side end portion of the concavo-convex layer is the shortest. The length M from the end portion on the distal end side to the end portion on the proximal end side of the concave-convex layer 203 is assumed to be a length M. The gas sensor 1 of this example has an axial length L of 3.5 mm and an axial length M of 2.5 mm.

  Next, the function and effect of the gas sensor according to this example will be described. In the gas sensor 1 of the present example, a filling portion 14 is formed between the gas sensor element 2 and the housing 10 by a powder filler made of relatively large-diameter particles within the specific range described above. Since the powder filler consisting of large particles does not contain much air inside, the specific gravity can be easily increased at the time of filling only by pressurization. Therefore, it is possible to easily obtain a dense, high-density and high specific gravity filling portion 14 and to obtain a filling portion 14 having high sealing performance. Furthermore, the gap between the powder fillers in the filling portion 14 is reduced because the filling portion 14 is densified and has a high density and a specific gravity. Therefore, it is difficult for liquid components to enter due to capillary action. Therefore, it is possible to provide the gas sensor 1 which is difficult for liquid components to enter between the housing 10 and the gas sensor element 2 and has excellent airtightness.

  The gas sensor 1 of this example is installed in an exhaust system of an automobile internal combustion engine and used for combustion control. In this case, the gas to be measured contains gasoline. Since the gas sensor 1 of this example has a dense filling part, it is possible to prevent gasoline in the gas to be measured from leaking to the atmosphere 120 through the filling part 14.

  The powder filler is made of talc, and the talc powder is a layered compound of scaly particles, which is cleaved in the laminar direction when pressed, and the layered structure of the talc scaly particles is not broken, and the particles are further broken. Since the flaky particles are soft, the scaly particles are collapsed and filled in the filling portion so as to fill the gaps remaining there slightly, so that the specific gravity increases and high sealing performance can be obtained.

  Furthermore, a filling auxiliary material can be added to the filling portion 14. By adding the filling auxiliary material, since the filling auxiliary material fills the space between the particles in the powder filling material, further increase in the density of the filling portion 14 can be easily realized. For example, the filling auxiliary material is made of monoaluminum phosphate and is a liquid compound containing crystal water. Therefore, during pressurization, the primary aluminum phosphate enters the gaps between the powder fillers, and the filling auxiliary material can fill the gaps between the filler particles and the contact surfaces between the particles. Accordingly, the gap is reduced, and a high-density filling portion 14 can be obtained.

  The mixing of talc and filling aids is performed as follows. Weigh talc and filling aid and add filling aid to talc. Next, an appropriate amount of water is added in order to mix uniformly, and the talc particles are uniformly mixed with a rotary mixer or the like, and then preliminarily formed into a ring shape in the manner described above to produce the filling portion 14. To do. Alternatively, in order to facilitate uniform mixing, water can be added to the filling aid and mixed with a rotary mixer or the like while sprayed onto the talc powder in the form of a mist. When mixed in this way, talc and the filling auxiliary material can be mixed in a short time, and the talc particles can be mixed uniformly with almost no collapse.

  (Embodiment 2) This embodiment will explain the measurement of the sealing performance in the filling portion of the gas sensor shown in Embodiment 1. First, the procedure for measuring the sealing performance of the gas sensor will be described below. As shown in FIG. 3A, the gas sensor 1 is set with the base end facing downward. Next, the sealing tape 41 is wound so as to cover the outer surface of the gas side cover to be measured. As shown in FIG. 3B, 0.5 cc of gasoline is injected into the measured gas side cover using an injector 42 and left for a certain period of time. Then remove the sealing tape 41 and discard the remaining gasoline.

  As shown in FIG. 3C, the cap is removed and the front end side of the gas sensor 1 is turned downward. Then, the gasoline remaining in the measured gas side cover is discarded. In this state, the heater of the gas sensor 1 was energized at 13.5 V, and the output of the gas sensor 1 was monitored for 2 hours. The monitoring result is shown in FIG. As shown in FIG. 4, although the sensor output is substantially constant at the beginning, the output is reduced from a certain time, and after the state of low output continues for a while, it returns to the original output again.

  The point at which the sensor output decreases by z volts as shown in FIG. In the evaluation of the samples according to the following examples, a gas sensor with a decrease in output of 0.05 V is evaluated as ◎, 0.05 to 0.1 V is evaluated as ◯, and 0.1 V or more is evaluated as ×. The smaller the gas sensor output decreases, the higher the gasoline sealability of the filling part, and the better the gas sensor. Conversely, the greater the decrease in gas sensor output, the lower the gasoline sealability of the filling section, and the poorer the performance.

  In the measurement of this example, gas sensors having the structure described in Example 1 are prepared as Samples 1 to 25. Tables 1 and 2 show the particle size distribution of the powder filler used to constitute the filling portion of each gas sensor as a sample. Further, some of the powder fillers are denoted by symbols P1 to P11 (see the column of particle size distribution type, which will be used in Example 3 and later). The particle size was measured using a sieve particle size distribution meter. The data after the decimal point is rounded off.

  P1 and P2 are too small in particle size, P10 is too large in particle size, and it is clear from Tables 1 and 2, but particles having a particle size of 80 to 5000 μm are 80% by weight of the total weight of the powder filler. The condition of occupying the above is not satisfied.

  P11 is a powder filler having a relatively wide range of particle size distribution in which fine particles and large particles are mixed, and particles having a particle size of 80 to 5000 μm account for 80% or more of the total. Samples 18 to 25 are gas sensors using a powder filler called P6, samples 1 to 23 are powder fillers made of talc, and samples 24 and 25 are powder fillers obtained by adding alumina to talc.

  Table 2 shows the results of the above-described measurement for Samples 1 to 25 described above. From Tables 1 and 2, it was found that Samples 1 and 2 relating to P1 and P2 were too small in particle size, the gasoline sealability of the filling portion was low, and the output of the gas sensor was reduced. Moreover, it turned out that the sample 16 concerning P10 is too large in particle size, has a low gasoline sealability, and the output of the gas sensor is reduced.

  From the above, it is possible that an excellent gas sensor can be obtained when the powder filler is in a state in which particles having a particle size of 80 to 5000 μm account for 80% by weight or more of the total weight of the powder filler before filling. all right. Furthermore, in the gas sensors according to P4 to P7 (sample 4 to sample 13), before the powder filler is filled, particles having a particle size of 100 to 1000 μm occupy 80% by weight or more of the entire powder filler. Therefore, in any gas sensor, the evaluation is ◎, and it can be seen that the filling portion exhibits excellent gasoline sealing performance.

  Samples 18 to 25 all have a filling portion made of a powder filler having the same particle size distribution P6. Sample 18 had a height in the axial direction of the filling portion as short as 1 mm and was evaluated as ◯, but the output was significantly reduced. Samples 19 to 22 are samples having different heights in the axial direction of the filling portion. In both cases, a determination of “◎” was obtained.

  Sample 23 was boron nitride, and samples 24 and 25 were talc added with alumina. Sample 23 was ◎, but samples 24 and 25 were composed of talc and alumina. Although the evaluation of sample 25 was ◯, the output was considerably reduced. From these points, it was found that the axial height of the filling part was somewhat high and the type of powder filler material also affected the output. And it turned out that the filling part which was more excellent in gasoline-sealing property by using especially talc and boron nitride was obtained.

（実施例３）本例は，分級により細かい粒子を取り除いた粉末充填材とガスセンサの性能との関係について評価を行った。また，性能評価などは実施例２に記載した方法で行った。試料９９は，８０μｍ以下の細かい粒子から５０００μｍ以上の粗い粒子までを含んだ粉末充填材であり，特に分級を施していない材料である。試料１００から１０３は，試料９９にかかる粉末充填材にそれぞれ目開きの異なる篩で粒子を乾式篩分級して細かい粒子を取り除いた材料である。また，試料１０４は遠心式気流分級で８０μｍ以下の細かい粒子を取り除き，試料１０５は遠心式湿式分級で８０μｍ以下の粒子を取り除いた粉末充填材である。

(Example 3) In this example, the relationship between the performance of the gas sensor and the powder filler from which fine particles were removed by classification was evaluated. Moreover, performance evaluation etc. were performed by the method described in Example 2. The sample 99 is a powder filler containing fine particles of 80 μm or less to coarse particles of 5000 μm or more, and is not particularly classified. Samples 100 to 103 are materials obtained by subjecting the powder filler according to sample 99 to dry sieving with particles having different openings to remove fine particles. Sample 104 is a powder filler from which fine particles of 80 μm or less are removed by centrifugal air classification, and sample 105 is a powder filler from which particles of 80 μm or less are removed by centrifugal wet classification.

  Table 3 shows the particle size distribution, classification method, evaluation, and particle size distribution type of each sample. It was found that sample 99 contained a lot of extremely fine particles, so the gasoline sealability of the filling portion was low, and as a result, the output of the gas sensor was reduced. The other samples were evaluated as ○ or ◎, and it was found that by removing fine particles from these points, the filling part exhibited excellent gasoline sealability. From comparison between the sample 100 and other samples, it was found that a smaller number of finer particles of 80 μm or less exhibited higher sealing performance.

（実施例４）本例は，分級により粗い粒子を取り除いた粉末充填材とガスセンサの性能との関係について評価を行った。また，性能評価などは実施例２に記載した方法で行った。試料１０６は８０μｍ以下の細かい粒子から５０００μｍ以上の粗い粒子まで含んだ粉末充填材であり，特に分級を施していない材料である。試料１０７から１０９は，試料１０６にかかる粉末充填材をそれぞれ目開きの異なる篩で粒子を乾式篩分級して粗い粒子を取り除いた材料である。また，試料１１０は遠心式気流分級で１０００μｍ以上の粗い粒子を取り除き，試料１１１は遠心式湿式分級で１０００μｍ以上の粒子を取り除いた粉末充填材である。これらの各試料の粒度分布や分級方法，評価，粒度分布種類について表４に記載した。

(Example 4) In this example, the relationship between the performance of the gas sensor and the powder filler from which coarse particles were removed by classification was evaluated. Moreover, performance evaluation etc. were performed by the method described in Example 2. The sample 106 is a powder filler containing fine particles of 80 μm or less to coarse particles of 5000 μm or more, and is not particularly classified. Samples 107 to 109 are materials obtained by classifying particles of the powder filler according to sample 106 with a sieve having different openings, and removing coarse particles. Sample 110 is a powder filler from which coarse particles of 1000 μm or more are removed by centrifugal air classification, and sample 111 is a powder filler from which particles of 1000 μm or more are removed by centrifugal wet classification. Table 4 shows the particle size distribution, classification method, evaluation, and particle size distribution type of each sample.

  It was found that the sample 106 was extremely large in diameter and contained many coarse particles, so that the gasoline sealability of the filling portion was low, resulting in a decrease in the output of the gas sensor. The evaluation of other samples was ○ or ◎, and it was found that by removing coarse particles from these points, the filling part exhibited excellent gasoline sealability. Further, it was found from the comparison between the sample 107 and other samples that the performance without the coarse particles having a particle size of 5000 μm or more is more excellent.

（実施例５）本例は，充填補助材を含む充填部を持ったガスセンサについて性能評価を行った。なお，性能評価は実施例２に記載した方法で行った。表５に示すごとく，用いた粉末充填材はいずれもタルクで，添加した充填補助材は，試料２６〜３２は第１リン酸アルミニウム水溶液，試料３３〜３７はケイ酸ソーダ水溶液である。試料３８〜４２はケイ酸カリウム水溶液である。試料４３は第１リン酸アルミニウム水溶液とケイ酸ソーダ水溶液，試料４４は第１リン酸アルミニウム水溶液とケイ酸カリウム水溶液である。これらはいずれも，室温（２０℃）において液状である無機化合物水溶液である。また，充填補助材の添加量は粉末充填材１００重量部に対する重量部で記載した。

(Example 5) In this example, the performance of a gas sensor having a filling portion containing a filling auxiliary material was evaluated. The performance evaluation was performed by the method described in Example 2. As shown in Table 5, the powder filler used was talc, and the added fillers were the first aluminum phosphate aqueous solution for samples 26 to 32 and the sodium silicate aqueous solution for samples 33 to 37. Samples 38 to 42 are aqueous potassium silicate solutions. Sample 43 is a first aluminum phosphate aqueous solution and sodium silicate aqueous solution, and sample 44 is a first aluminum phosphate aqueous solution and a potassium silicate aqueous solution. These are all inorganic compound aqueous solutions that are liquid at room temperature (20 ° C.). Moreover, the addition amount of the filling auxiliary material was described in parts by weight with respect to 100 parts by weight of the powder filler.

  The evaluation of the sample will be described. As shown in Table 5, it was found that for samples 26 to 32 using the first aluminum phosphate aqueous solution, samples 27 to 31 were ◎, and an excellent gas sensor with particularly small output reduction was obtained. Although the evaluation of the sample 26 and the sample 32 is (circle), the output fell considerably.

  Samples 33 to 37 use sodium silicate aqueous solution. Particularly, Samples 35 and 36 have excellent output due to ◎ and small output drop, and Sample 34 also exhibited excellent performance according to these. Samples 33 and 37 were evaluated as ◯, but the output was considerably reduced.

  Samples 38 to 42 used an aqueous potassium silicate solution. Particularly, Samples 40 and 41 exhibited excellent gas sensors with excellent output in accordance with these, and Samples 39 and 41 exhibited excellent performance according to these. Although the samples 38 and 42 were evaluated as “good”, the output was considerably lowered.

  As described above, it was found that a filling portion excellent in gasoline sealability can be obtained by using the first aluminum phosphate aqueous solution and other substances described in Table 5 as the filling auxiliary material. This is because a filling auxiliary material made of an aqueous solution enters the gap between the powder fillers during pressurization, and a denser filling portion can be obtained. Furthermore, it has become clear from the above description and Table 5 that the addition amount of the filling auxiliary material is particularly preferably 0.1 to 10 parts by weight.

  Sample 43 is added with both the first aluminum phosphate aqueous solution and sodium silicate aqueous solution, and sample 44 is added with 1 part by weight of both the first aluminum phosphate aqueous solution and the potassium silicate aqueous solution. Both obtained excellent gas sensors. It was also found that different types of filling aids can be used in combination.

（実施例６）本例は，実施例５とは異なる充填補助材を含む充填部を持ったガスセンサについて性能評価を行った。性能評価は実施例２に記載した方法に準じて行う。表６に示すごとく，用いた粉末充填材はいずれもタルクで，添加した充填補助材の種類は表６に示すような物質である。これらは温度６００℃以下の環境で液状となることが可能な無機化合物である。また，充填補助材の添加量は粉末充填材１００重量部に対する重量部で記載した。

(Example 6) In this example, the performance of a gas sensor having a filling portion containing a filling auxiliary material different from that in Example 5 was evaluated. The performance evaluation is performed according to the method described in Example 2. As shown in Table 6, the powder filler used is talc, and the type of the filler auxiliary material added is a substance as shown in Table 6. These are inorganic compounds that can be liquefied in an environment at a temperature of 600 ° C. or lower. Moreover, the addition amount of the filling auxiliary material was described in parts by weight with respect to 100 parts by weight of the powder filler.

  The evaluation of the sample will be described. As shown in Table 6, the evaluation of Samples 46 to 48 using barium hydroxide was “◎”, and it was found that a filled portion having particularly excellent gasoline sealability was obtained. Although the evaluation of the sample 45 and the sample 49 is (circle), the output fell considerably. For this reason, it has been found that an excellent performance may not be obtained if the addition amount of the filling auxiliary material is too large or too small. In addition, the evaluations of the samples 50 to 56 using the filling auxiliary material made of other materials were ◎, and it was found that a particularly excellent gasoline-sealed filling portion with a small output decrease was obtained.

（実施例７）表１に記載したいくつかの粉末充填材を加圧し，成形体となし，この成形体の比重について測定した。この結果を図５に示す。Ｐ１は前述した表１より明らかであるが，非常に細かい粒径の粒子より構成されており，成形比重が他のものと比較して低いことが分かる。このようにＰ１の成形比重は低いため，Ｐ１を粉末充填材として使用し，充填部を構成した際に，ガソリンシール性能に劣る充填部しか得られないのである。（表１，表２参照）他のＰ３，Ｐ６，Ｐ７は高い成形比重を有しており，ガソリンシール性に優れた充填部が得られるのである（表１，表２参照）
（実施例８）本例は，図６〜図１１に示すごとく，ガスセンサにおける充填部の軸方向高さ，ガスセンサ素子における凹凸層や電極保護層の基端側の端部等の位置関係について説明する。図６〜図１０に示すごとく，ガスセンサ素子を構成する固体電解質体２０の表面に凹凸層２０３が設けてあり，図示はされていないが，上記凹凸層２０３を覆うように外側電極が設けてあり，該外側電極を覆うように電極保護層２０５が設けてある。なお，図１１にかかるガスセンサは凹凸層を持っていない。

(Example 7) Several powder fillers described in Table 1 were pressurized to form a compact, and the specific gravity of the compact was measured. The result is shown in FIG. P1 is clear from the above-mentioned Table 1, but is composed of particles having a very fine particle size, and it can be seen that the molding specific gravity is lower than that of the others. Thus, since the molding specific gravity of P1 is low, when P1 is used as a powder filler and the filling portion is configured, only a filling portion inferior in gasoline seal performance can be obtained. (See Tables 1 and 2) The other P3, P6 and P7 have a high molding specific gravity, and a filling part excellent in gasoline sealability can be obtained (see Tables 1 and 2).
(Embodiment 8) In this example, as shown in FIG. 6 to FIG. 11, the positional relationship between the axial height of the filling portion in the gas sensor, the concavo-convex layer in the gas sensor element, the end portion on the base end side of the electrode protective layer, etc. To do. As shown in FIGS. 6 to 10, an uneven layer 203 is provided on the surface of the solid electrolyte body 20 constituting the gas sensor element, and although not shown, an outer electrode is provided so as to cover the uneven layer 203. , An electrode protective layer 205 is provided so as to cover the outer electrode. Note that the gas sensor according to FIG. 11 does not have an uneven layer.

  6 to 11, a filling portion 14 is formed between the solid electrolyte body 20 and the housing 10. The axial length L of the filling portion 14 is the same as in the first embodiment. The distance between the end portion 141 on the distal end side of the filling portion 14 and the end portion on the proximal end side 142 is a length parallel to the axial direction. Further, the method for removing the base end side of the uneven layer 203 and the axial length M are also described in the first embodiment. Further, the base end side of the electrode protective layer 205 is also defined with the same definition as the concave / convex layer 203, and the axial length N is also defined with the same definition as the concave / convex layer 203. Therefore, the axial length of the concavo-convex layer 203 is the distance M between the proximal end of the concavo-convex layer 203 and the end of the filling layer 14, and the axial length of the electrode protective layer 205 is the electrode protective layer 205. This is a distance N between the base end side end and the end of the filling layer 14 on the front end side.

  The gas sensor shown in FIG. 6 has a shape that satisfies L> M> N. In the gas sensor shown in FIG. 7, M = N = 0 and L = 4 mm. In other words, at the end portion 141 of the filling portion 14, the concavo-convex layer 203 also has the end portion on the base end side of the electrode protective layer 205. In the gas sensor according to FIG. 8, L is 4 mm, but both M and N are −1 mm. This means that neither the concavo-convex layer 203 nor the electrode protective layer 205 reaches the end of the filling portion 14 on the front end side. In addition, as shown in FIG. 8, the reason why-is added in the axial length is that the end on the front end side of the filling portion 14 is defined as the origin axis 0, the base end side is defined as +, and the front end side is defined as-. It is.

  The gas sensor according to FIG. 9 has N = 0 mm, but L = 4 mm and M = 3.5 mm. And it has the edge part of the base end side of the uneven | corrugated layer 203 in the position which descended 0.5 mm to the front end side from the edge part 142 of the base end side of the filling part 14. That is, the distance P between the proximal end 142 of the filling portion 14 and the proximal end of the uneven layer 203 is 0.5 mm.

  The gas sensor according to FIG. 10 has N = 0 mm, L and M are both 4 mm, that is, the uneven layer 203 is formed up to the end of the filling portion 14 on the proximal end side. Further, FIG. 11 shows a gas sensor without an uneven layer, in which L is 4 mm, N is 0, that is, the electrode protective layer 205 is provided only up to the position of the end portion 141 on the front end side of the filling portion 14. Other details are the same as in the first embodiment, and the detailed operational effects are also the same as in the first embodiment.

  (Example 9) In this example, the relationship between the axial length of the uneven layer and the axial length of the electrode protective layer and the performance of the gas sensor was evaluated. As shown in Table 7, the axial lengths of the filling portions are all 4 mm, but samples 57 to 70 having different lengths in the axial direction of the uneven layer and the electrode protective layer are prepared. As a result of performing the performance evaluation of these samples by the method described in Example 2, Sample 60, Sample 64, and Sample 67 were x.

  This is because the sample 60 has a length of the concavo-convex layer of 5 mm, that is, the concavo-convex layer is formed so as to protrude from the base end side of the filling portion, so that gaps and micropores into which liquid components easily enter are formed. In the sample 64, the electrode protective layer protrudes beyond the filling portion, and the surface of the electrode protective layer has irregularities, so that gaps and micropores into which liquid components easily enter are formed as described above. In the sample 67, both the uneven layer and the electrode protective layer protrude from the filling portion, so that the liquid component is very likely to enter.

（実施例１０）本例は，分級により細かい粒子と粗い粒子とを取り除いた粉末充填材とガスセンサの性能との関係について評価を行った。また，性能評価などは実施例２に記載した方法で行った。試料１１３，１２１，１２５は，８０μｍ以下の細かい粒子から５０００μｍ以上の粗い粒子まで含んだ粉末充填材である。

(Example 10) In this example, the relationship between the performance of the gas sensor and the powder filler from which fine particles and coarse particles were removed by classification was evaluated. Moreover, performance evaluation etc. were performed by the method described in Example 2. Samples 113, 121, and 125 are powder fillers containing fine particles of 80 μm or less to coarse particles of 5000 μm or more.

  Samples 114 to 120 are powder fillers obtained by removing fine particles from the sample 113 with a sieve having an aperture of 40, 80, 100, and 125 μm and removing coarse particles with a sieve having an aperture of 710, 1000, and 5000 μm. Samples 122 to 124 are powder fillers obtained by removing coarse particles and fine particles from the sample 121 and samples 126 to 128 using a sieve.

  Sample 129 is a powder filler from which particles of 80 μm or less and 5000 or more are removed by centrifugal air classification, and sample 130 is a powder filler from which particles of 80 μm or less and 5000 or more are removed by centrifugal wet classification. Details are shown in Tables 8 and 9.

  It was found that Samples 113, 121, and 125 contained a lot of extremely fine particles and coarse particles, so that the gasoline sealability of the filling portion was low and the output of the gas sensor was lowered. On the other hand, it was found that Samples 114 to 120, 122 to 124, and 126 to 128 from which coarse particles and fine particles were removed obtained good results (◎ and ○). However, it was found that the performance of the samples 114, 122, and 126, in which the amount of fine particles and coarse particles is slightly larger, is slightly inferior.

（実施例１１）本例は，充填部に充填補助材が含まれており，粉末充填材として実施例１の表１，２，実施例１０の表８，９に記載したＰ１，Ｐ３，Ｐ６，Ｐ８，Ｐ１０，Ｐ１６〜２１を用い，また充填補助材の添加量も適当に変更した試料の性能について評価した。また，性能評価などは実施例２に記載した方法で行った。各試料７１〜７７，１３１〜１３６において使用する粉末充填材は表１０に示すとおりいずれもタルク，充填補助材は第一リン酸アルミニウム水溶液，そして添加量は同表に示すごとく変化させる。

(Embodiment 11) In this embodiment, a filling auxiliary material is included in the filling portion, and P1, P3, and P6 described in Tables 1 and 2 of Example 1 and Tables 8 and 9 of Example 10 are used as powder fillers. , P8, P10, P16-21, and the performance of the sample was evaluated with the addition amount of the filling aid appropriately changed. Moreover, performance evaluation etc. were performed by the method described in Example 2. As shown in Table 10, the powder filler used in each of the samples 71 to 77 and 131 to 136 is talc, the filling auxiliary material is a first aluminum phosphate aqueous solution, and the addition amount is changed as shown in the table.

  When the performance of each sample was evaluated, the samples 72 to 76, 132, 134, and 136 were able to obtain excellent gasoline seal performance as ◎. The evaluation of the sample 71 is ◯, but the particle size distribution of the used powder filler is P1 and the particle size is too fine. The evaluation of the sample 77 is ◯, but the particle size distribution of the used powder filler is P10. The particle size is too coarse.

  The evaluation of the sample 131 is ◯, but the particle size distribution of the used powder filler is P16 and contains many fine and coarse particles. The evaluation of the sample 133 is ◯, but the particle size distribution of the used powder filler is Contains many fine particles at P18. Moreover, although evaluation of the sample 135 is (circle), the particle size distribution of the used powder filler is P20, and many coarse particles are included. Thus, these samples containing fine and coarse particles had a slightly poor gasoline seal performance.

（実施例１２）本例は，粉末充填材として実施例１の表１，表２，実施例１０の表８，９に記載した，Ｐ１，Ｐ３，Ｐ６，Ｐ８，Ｐ１０，Ｐ１６〜Ｐ２１を用い，また凹凸層や電極保護層の長さも適当に変更した試料の性能について評価した。また，性能評価などは実施例２に記載した方法で行った。各試料７８〜８４，１３７〜１４２において使用する粉末充填材は表１１に示すとおり，また，凹凸層や電極保護層の長さも表１１に記載した。

(Example 12) This example uses P1, P3, P6, P8, P10, P16 to P21 described in Tables 1 and 2 of Example 1 and Tables 8 and 9 of Example 10 as powder fillers. In addition, the performance of the samples in which the lengths of the concave and convex layers and the electrode protective layer were appropriately changed were evaluated. Moreover, performance evaluation etc. were performed by the method described in Example 2. The powder filler used in each of the samples 78 to 84 and 137 to 142 is shown in Table 11, and the lengths of the uneven layer and the electrode protective layer are also shown in Table 11.

  When the performance of each sample was evaluated, samples 79 to 83, 138, 140, and 142 were excellent and excellent gas sensors could be obtained. In addition, sample 78 has a particle size distribution of the used powder filler P1 and the particle size is too fine, sample 84 has a particle size distribution of the used powder filler P10 and is too coarse, and sample 137 has the powder filler used. The particle size distribution of P16 is large in both fine and coarse particles. Sample 139 has a particle size distribution of the powder filler used in P18 and is too fine, and sample 141 has a particle size distribution of P20 in the particle size distribution of P20. The diameter is too coarse. And the filling part concerning these samples had the length of an axial direction and the length of an uneven | corrugated layer or an electrode protective layer, and the gasoline seal performance was a little inferior.

（実施例１３）本例は，充填部に充填補助材を添加し，また凹凸層や電極保護層の長さも適当に変更した試料の性能について評価した。また，性能評価などは実施例２に記載した方法で行った。各試料８５〜９１において使用する粉末充填材，充填補助材，添加量は表１２に示すとおり，また，凹凸層や電極保護層の長さも表１２に記載した。各試料の性能を評価すると，試料８６〜９０は◎と優れたガスセンサを得ることができたが，試料８５は○で，充填部の軸方向長さと凹凸層や電極保護層が同じであるため，若干劣るガソリンシール性能しか得られなかった。

(Example 13) In this example, the performance of a sample in which a filling auxiliary material was added to the filling portion and the lengths of the uneven layer and the electrode protective layer were appropriately changed was evaluated. Moreover, performance evaluation etc. were performed by the method described in Example 2. As shown in Table 12, the powder filler, filling auxiliary, and addition amount used in each sample 85 to 91 are shown in Table 12, and the lengths of the uneven layer and the electrode protective layer are also shown in Table 12. When evaluating the performance of each sample, samples 86 to 90 were able to obtain excellent gas sensors as ◎, but sample 85 was ○, and the axial length of the filling portion was the same as the concave and convex layer and the electrode protective layer. Only a slightly poor gasoline seal performance was obtained.

  Sample 91 was ◯, and since the axial length of the filling portion was the same as the concave and convex layer and the electrode protective layer, only slightly poor gasoline sealing performance was obtained. In addition, the sample 85 has a small amount of addition of the filling auxiliary material, and it is difficult to say that a sufficient effect has been obtained, and the sample 91 on the contrary has a large addition amount of the filling auxiliary material, which rather deteriorates the sealing performance of the filling portion. End up.

（実施例１４）本例は，粉末充填材として実施例１の表１，表２に記載した，Ｐ１，Ｐ３，Ｐ６，Ｐ８，Ｐ１０を用い，充填補助材を添加し，また凹凸層や電極保護層の長さも適当に変更した試料の性能について評価した。また，性能評価などは実施例２に記載した方法で行った。各試料９２〜９８において使用する粉末充填材，充填補助材，添加量は表１３に示すとおり，また，凹凸層や電極保護層の長さも表１３に記載した。

(Example 14) In this example, P1, P3, P6, P8, and P10 described in Tables 1 and 2 of Example 1 were used as powder fillers, filling auxiliary materials were added, and uneven layers and electrodes were used. The performance of the sample in which the length of the protective layer was also appropriately changed was evaluated. Moreover, performance evaluation etc. were performed by the method described in Example 2. As shown in Table 13, the powder fillers, filling auxiliary materials, and addition amounts used in the samples 92 to 98 are shown in Table 13, and the lengths of the uneven layer and the electrode protective layer are also shown in Table 13.

  When evaluating the performance of each sample, samples 93 to 97 were able to obtain excellent gas sensors as ◎, but sample 92 was ○, and the particle size distribution of the powder filler used was P1, and the particle size was too fine. Moreover, because the axial length of the filling portion is the same as the length of the uneven layer and the electrode protective layer, an excellent gasoline seal performance could not be obtained.

  Sample 98 is ◯, the particle size distribution of the powder filler used is P10, and the particle size is too large, and the axial length of the filling portion is the same as the length of the uneven layer or electrode protective layer. Therefore, excellent gasoline seal performance could not be obtained. In addition, both Samples 92 and 98 have a small amount of filling auxiliary material, and it is difficult to say that a sufficient effect is obtained.

Sectional explanatory drawing of the gas sensor in Example 1. FIG. The principal part explanatory drawing of the filling part in Example 1. FIG. Explanatory drawing which shows the test method with respect to the sealing performance of gasoline in Example 2. FIG. FIG. 6 is a diagram showing the relationship between the sensor output and the monitoring time in the test in Example 2. The diagram which shows the shaping | molding specific gravity in P1, P3, P6, and P7 in Table 1 in Example 7. FIG. Explanatory drawing which shows the axial direction length L, M, and N of a filling part, an uneven | corrugated layer, and an electrode protective layer in Example 8. FIG. Explanatory drawing of the filling part in which the axial direction length of an uneven | corrugated layer and an electrode protective layer is 0 in Example 8. FIG. Explanatory drawing which shows the filling part in which the axial direction length of an uneven | corrugated layer and an electrode protective layer is -1 mm in Example 8. FIG. Explanatory drawing which shows the filling part whose axial direction length of the electrode protective layer is 0 in Example 8. FIG. Explanatory drawing which shows the filling part in which the edge part of the base end side of a filling part and the edge part of the base end side of an uneven | corrugated layer correspond in Example 8. FIG. Explanatory drawing of the gas sensor element in which only the electrode protective layer is provided in Example 8, and a filling part.

Explanation of symbols

1. . . Gas sensor,
10. . . Housing 14. . . Filling section,
2. . . Gas sensor element,
203. . . Uneven layer,
205. . . Electrode protective layer,

Claims (4)

A powder filling comprising a housing and a gas sensor element inserted through the housing, wherein at least a part between the housing and the gas sensor element is added with a filling auxiliary material made of a first aluminum phosphate aqueous solution. The gas sensor element is hermetically sealed by a filling portion filled with a material, and the surface of the gas sensor element is formed with at least one of a concavo-convex layer made of a porous material and an electrode protective layer. The proximal end of the layer and the electrode protective layer is the same as the proximal end of the filling portion, or is more distal than the proximal end of the filling portion Gas sensor.   2. The base end side end portion of the concavo-convex layer or the base end side end portion of the electrode protection layer is at least 0.5 mm or more from the base end side end portion of the filling portion. A gas sensor characterized by that.   3. The base end side end portion of the electrode protection layer according to claim 1 or 2 is the same as the end portion on the tip end side of the filling portion or on the tip end side from the end portion on the tip end side of the filling portion. A gas sensor. 2. The gas sensor according to claim 1, wherein the addition amount of the filling auxiliary material is 0.1 to 10 parts by weight with respect to 100 parts by weight of the powder filler.

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