Gas sensor ceramic chip core installation protection structure

Abstract

The utility model relates to an installation protection structure for a ceramic chip core of a gas sensor. The installation protection structure comprises a waste gas cover, a base, a metal protection sleeve and a rubber sealing plug, the waste gas cover is connected with the base and comprises an outer cover and an inner cover, the base is connected with the metal protective sleeve, a first fixing piece, a powder pressing piece and a second fixing piece are sequentially arranged in an inner hole of the base from inside to outside, and the ceramic chip core penetrates through chip core via holes of the first fixing piece, the powder pressing piece and the second fixing piece to be arranged in the base. Powder breaking structures are arranged at the ends, making contact with the powder pressing piece, of the first fixing piece and the second fixing piece, the second fixing piece is of a stepped structure and comprises a thick part and a thin part, and an edge deformation fixing part is arranged at the position, opposite to the connecting position of the thick part and the thin part of the second fixing piece, of the base; a terminal mounting hole communicated with the sheet core via hole is formed in one end, close to the metal protective sleeve, of the thin part; and a rubber sealing plug is arranged in an inner hole at the tail part of the metal protective sleeve. The structure ensures the installation and use of the ceramic chip core, and prevents the chip core from being damaged.

Description

Technical Field

[0001] The utility model belongs to the technical field of gas sensors, and relates to an oxygen sensor or a nitrogen oxide sensor for detecting exhaust gas of an automobile engine. Specifically, it relates to an installation and protection structure for a ceramic chip core of a gas sensor. Background Art

[0002] The existing outer protective shell of a gas sensor (oxygen sensor or nitrogen oxide sensor) consists of an exhaust gas cover, a base, a metal protective sleeve, a tail seal fluororubber plug, and a wire harness protective sleeve; the exhaust gas cover is designed as a double-layer structure, and the intake holes and exhaust holes of the inner and outer exhaust gas covers are arranged in a staggered manner and do not overlap, which can effectively avoid the problem of the chip cracking when encountering water droplets at high temperature. However, due to the unreasonable fixing method of the ceramic chip core in the existing gas sensor, the chip core is easily damaged. Content of the Utility Model

[0003] In view of the above technical problems and disadvantages, the purpose of the utility model is to provide an installation and protection structure for a ceramic chip core of a gas sensor. This structure also adopts a double-layer exhaust gas cover, and the intake holes and exhaust holes of the inner and outer exhaust gas covers are arranged in a staggered manner and do not overlap, avoiding the chip cracking when encountering water droplets at high temperature; in addition, a first fixing member, a powder pressing sheet, and a second fixing member are arranged in the inner hole of the base. The first fixing member and the second fixing member clamp the ceramic chip core by extruding the powder pressing sheet so that the ceramic chip core is not detached, ensuring the installation of the ceramic chip core and avoiding damage to the chip core.

[0004] An installation and protection structure for a ceramic chip core of a gas sensor, comprising an exhaust gas cover, a base, a metal protective sleeve, and a rubber seal plug;

[0005] Wherein, the exhaust gas cover is connected to the base. The exhaust gas cover includes an outer cover and an inner cover arranged inside the outer cover. The end face of the outer cover is provided with an outer exhaust gas unit communicated with the inside of the outer cover at the axial center position, and a plurality of first intake holes are further arranged around the outer exhaust gas unit on the end face of the outer cover; the top of the outer exhaust gas unit is provided with a first exhaust hole; the end face of the inner cover is provided with an inner exhaust gas unit communicated with the inside of the inner cover. The inner exhaust gas unit is arranged inside the outer exhaust gas unit, and the top of the inner exhaust gas unit is provided with a plurality of second exhaust holes, and the second exhaust holes are staggered and non-overlapping with the first exhaust hole; a plurality of second intake holes are arranged on the side wall of the inner cover;

[0006] The base is connected to the metal protective sleeve. Inside the inner hole of the base, a first fixing member, a powder tablet, and a second fixing member are sequentially arranged from inside to outside. Chip holes are provided on the first fixing member, the powder tablet, and the second fixing member. The ceramic chip passes through the chip holes of the first fixing member, the powder tablet, and the second fixing member and is arranged inside the base. At one end of the first fixing member and the second fixing member in contact with the powder tablet, a first powder-breaking structure and a second powder-breaking structure are provided. The first powder-breaking structure and the second powder-breaking structure are used to fully break the powder tablet when axial pressure is applied, and make the broken powder be compacted again to fix the ceramic chip. The second fixing member is a stepped structure, including a thick part inserted into the inner hole of the base and a thin part exposed outside the base. At a position of the base opposite to the connection of the thick part and the thin part of the second fixing member, an edge deformation fixing part is provided, and the second fixing member is fixed through the deformation of the edge deformation fixing part. At one end of the thin part close to the metal protective sleeve, a terminal installation hole communicating with the through hole is provided, and a wiring terminal connected to the ceramic chip is installed in the terminal installation hole. The wire at the other end of the wiring terminal extends into the metal protective sleeve. A rubber sealing plug is installed in the inner hole at the tail of the metal protective sleeve. The rubber sealing plug is provided with wire through holes matching the number of wires, and the rubber sealing plug is fixed by riveting the metal protective sleeve.

[0007] As a preference of the present utility model, the outer cover and the inner cover are in transitional or interference fit; the exhaust hood is installed at one end of the base by welding, and the metal protective sleeve is installed at the other end of the base by welding.

[0008] As a preference of the present utility model, the outer surface of the base is provided with an external thread at a position close to the exhaust hood and a hexagonal mating part at a position close to the metal protective sleeve; the inner hole of the base near the external thread end is designed as a conical hole.

[0009] As a preference of the present utility model, a wire harness protective sleeve is provided outside the wire extending to the outside of the metal protective sleeve, and the other end of the wire is connected to a connector.

[0010] As a preference of the present utility model, both the first fixing member and the second fixing member are ceramic parts. An enlarged hole is provided at a position of the first fixing member close to the exposed end of the ceramic chip; the powder-breaking structure at the end of the first fixing member is arranged on both sides of the chip hole, and is a structure protruding from the end face of the first fixing member and having a flat contact surface with the powder tablet; the powder-breaking structure of the second fixing member is a structure protruding from the end face of the second fixing member and having a flat contact surface with the powder tablet.

[0011] Preferably, a plurality of the first air inlet holes are arranged at equal intervals around the outer air outlet unit, and a plurality of the second air outlet holes are distributed at equal intervals around the first air outlet hole; the first air outlet hole, the second air outlet hole, and the first air inlet hole are all circular, and the inner diameter of the first air outlet hole is greater than that of the second air outlet hole; the second air inlet hole is crescent-shaped or semi-circular, and the crescent-shaped or semi-circular second air inlet hole is inclined and forms an acute angle with the axis of the gas sensor.

[0012] Preferably, a marking hole is further provided on the outer end face of the detail part, and the marking hole is used to identify the assembly direction.

[0013] Preferably, the enlarged hole is a circular hole, a rectangular hole or a square hole.

[0014] Advantages and beneficial effects of the present utility model:

[0015] 1. The installation protection structure provided by the present utility model still adopts a double waste gas hood structure, which can prevent water from entering the inner cavity and avoid chip cracking; in addition, the inner hood with an inclined crescent-shaped second air inlet hole structure has a good gas guiding effect, which can help the gas contact the chip core faster and improve the sensor performance.

[0016] 2. The front end (the end with the threaded end) of the base of the present utility model adopts a conical hole structure, and the space around the chip core is open, enabling the surrounding gas to circulate quickly and improving the sensor performance; in addition, the first fixing member also has an enlarged hole beneficial to air circulation near the outer leakage end of the chip core, and this design can make the sensor have a faster response speed.

[0017] 3. The powder breaking structure of the first fixing member and the second fixing member of the present utility model can make the powder break more fully. The broken powder is used to clamp the sensor ceramic chip core. Since the powder has good fluidity, when an external force is applied, the density gradually increases, which can play a role in clamping the ceramic chip core and avoid generating an impact force on the chip core and damaging the chip core; in addition, due to the relatively large density of the powder, it can play a sealing role and improve the sealing performance; in addition, the first fixing member and the second fixing member are ceramic parts, and the powder also has good insulation, which can avoid affecting the signal transmission of the chip core.

[0018] 4. The present utility model fixes the second fixing member by means of plastic deformation of the base metal, which is convenient for operation and makes full use of the characteristics of the metal material. Description of the drawings

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0020] Figure 1 Schematic exploded view of the installation protection structure of the present invention;

[0021] Figure 2 Schematic view of the installation protection structure of the present invention after being assembled with wires and connectors;

[0022] Figure 3 Schematic view of the outer cover of the present invention;

[0023] Figure 4 Schematic view of the inner cover of the present invention;

[0024] Figure 5 Schematic view of the base of the present invention;

[0025] Figure 6 For Figure 5 Partial sectional view;

[0026] Figure 7 Schematic diagram of the first fixing member of the present invention Figure 1 ;

[0027] Figure 8 Schematic diagram of the first fixing member of the present invention Figure 2 ;

[0028] Figure 9 Schematic diagram of the second fixing member of the present invention Figure 1 ;

[0029] Figure 10 Schematic diagram of the second fixing member of the present invention Figure 2 ;

[0030] Figure 11 Schematic view of the combination of the first fixing member, powder tablet, first fixing member and ceramic chip core.

[0031] Reference numerals: exhaust hood 1, base 2, metal protective sleeve 3, rubber sealing plug 4, wire harness protective sleeve 5, connector 6, wire 7, outer cover 11, inner cover 12, first fixing member 21, powder tablet 22, second fixing member 23, ceramic chip core 24, edge deformation fixing portion 25, outer air outlet unit 111, first air inlet hole 112, first air outlet hole 113, inner air outlet unit 121, second air inlet hole 122, second air outlet hole 123, first powder breaking structure 211, enlarged hole 212, second powder breaking structure 231, thick portion 232, thin portion 233, terminal mounting hole 2331, marking hole 2332. Detailed implementation manners

[0032] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0033] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "top end" and the like is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship when the product of this application is normally placed. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0034] In the description of the present application, it should also be noted that unless otherwise clearly defined and limited, the terms "arrangement" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0035] As Figures 1 to 11 shown, a gas sensor ceramic chip core installation and protection structure provided in this embodiment includes an exhaust hood 1, a base 2, a metal protective sleeve 3, and a rubber sealing plug 4;

[0036] Among them, the exhaust hood 1 is connected to the base 2. The exhaust hood 1 includes an outer hood 11 and an inner hood 12 disposed inside the outer hood. An external air outlet unit 111 communicating with the inside of the outer hood is provided at the axial center position of the end face of the outer hood 11, and a plurality of first air inlet holes 112 are further provided around the external air outlet unit 111 on the end face of the outer hood 11; a first air outlet hole 113 is provided at the top end of the external air outlet unit 11; an internal air outlet unit 121 communicating with the inside of the inner hood is provided at the end face of the inner hood 12. The internal air outlet unit 121 is disposed inside the external air outlet unit 111, and a plurality of second air outlet holes 123 are provided at the top end of the internal air outlet unit 121. The second air outlet holes 123 are offset from and do not overlap with the first air outlet holes 113; a plurality of second air inlet holes 122 are provided on the side wall of the inner hood 12;

[0037] The base 2 is connected to the metal protection sleeve 3. A first fixing member 21, a powder tablet 22, and a second fixing member 23 are sequentially provided in the inner hole of the base 2 from the inside to the outside. Chip through holes a are provided on the first fixing member 21, the powder tablet 22, and the second fixing member 23. The ceramic chip 24 passes through the chip through holes of the first fixing member 21, the powder tablet 22, and the second fixing member 23 and is disposed inside the base 2. First powder-breaking structures 211 and second powder-breaking structures 231 are provided at one end of the first fixing member 21 and the second fixing member 23 in contact with the powder tablet 22. The first powder-breaking structures 211 and the second powder-breaking structures 231 are used to fully break the powder tablet 22 when an axial pressure is applied, and the broken powder is re-compacted to fix the ceramic chip 24; the second fixing member 23 is a stepped structure, including a thick portion 232 inserted into the inner hole of the base 2 and a thin portion 233 exposed outside the base 2. An edge deformation fixing portion 25 is provided at a position of the base 2 opposite to the connection between the thick portion and the thin portion of the second fixing member 23, and the second fixing member 23 is fixed by the deformation of the edge deformation fixing portion 25; a terminal mounting hole 2331 communicating with the chip through hole a is provided at one end of the thin portion 233 close to the metal protection sleeve 3. A wiring terminal (not shown) connected to the ceramic chip 24 is installed in the terminal mounting hole 2331, and the wire 7 at the other end of the wiring terminal extends into the metal protection sleeve 3; a rubber sealing plug 4 is installed in the inner hole at the tail of the metal protection sleeve 3. The rubber sealing plug 4 is provided with wire through holes (not shown) matching the number of the wires 7, and the rubber sealing plug 5 is fixed by riveting the metal protection sleeve 3.

[0038] Further, in this embodiment, the outer hood 11 and the inner hood 12 are in a transition or interference fit, and the difference between the outer diameter of the inner hood 12 and the inner diameter of the outer hood 11 is <0.3 mm; the exhaust hood 1 is installed at one end of the base 2 by welding, and the metal protection sleeve 3 is installed at the other end of the base 2 by welding.

[0039] Further, as Figure 1 、 Figure 2As shown in the figure, in this embodiment, a wire harness protection sleeve 5 is provided outside the wire 7 extending to the outside of the metal protection sleeve 3. The other end of the wire 7 is connected to a connector 6. The wire harness protection sleeve 5 is a glass knitted insulating tube with a silicone coating.

[0040] Further, as Figure 3 , Figure 4 shown, in this embodiment, a plurality of the first air inlet holes 112 are arranged at equal intervals around the outgoing air unit 111, and a plurality of the second air outlet holes 123 are distributed at equal intervals around the first air outlet hole 113;

[0041] The first air outlet hole 113, the second air outlet hole 123, and the first air inlet hole 112 are all circular, and the inner diameter of the first air outlet hole 113 is larger than the inner diameter of the second air outlet hole 123; the second air inlet hole 122 is crescent-shaped or semi-circular, and the crescent-shaped or semi-circular second air inlet hole 122 forms a certain angle with the axis, and the size of the angle is preferably 30°. The inclined crescent-shaped second air inlet hole 122 has a good gas guiding effect on the inner cover, which can help the gas contact the ceramic chip core 24 faster and further improve the sensor performance.

[0042] Further, as Figure 5 , Figure 6 shown, in this embodiment, the outer surface of the base 2 is provided with an external thread near the exhaust gas hood 1 and a hexagonal mating portion near the metal protection sleeve 3; in addition, considering that the opening size of the exposed part of the ceramic chip core 24 of the base 2 is not easy to be too large, but in order to make the gas circulate better and improve the sensor performance, the exposed part of the ceramic chip core 24 of the base 2 also needs a larger space. Therefore, in the present invention, the inner hole of the base 2 near the external thread end is designed as a conical hole, which can make the space around the ceramic chip core 24 open, enable the surrounding gas to circulate quickly, and improve the sensor performance.

[0043] Further, as Figures 7 to 10 shown, in this embodiment, both the first fixing member 21 and the second fixing member 23 are ceramic members. The first fixing member 21 is provided with an enlarged hole 212 near the exposed end of the ceramic chip core. The enlarged hole 212 communicates with the chip through hole a, which is beneficial to air circulation. The enlarged hole 212 is a circular hole, a rectangular hole or a square hole. The broad space is conducive to gas exchange and enables the sensor to have a faster response speed; the first powder breaking structure 211 at the end of the first fixing member 21 is arranged on both sides of the chip through hole a, and is a structure protruding from the end face of the first fixing member 21 and having a flat contact surface with the powder compact 22; the second powder breaking structure 231 of the second fixing member 23 is a structure protruding from the end face of the second fixing member and having a flat contact surface with the powder compact 22.

[0044] Further, as Figure 9 , Figure 10As shown, in this embodiment, a marking hole 2332 is further provided on the outer end face of the detail part 233. The marking hole 2332 is used to identify the assembly direction, facilitating the assembly of the wiring terminal.

[0045] In this embodiment, the composition of the powder tablet is as follows:

[0046] ① Silicon dioxide (SiO 2 ): 61%;

[0047] ② Magnesium oxide (MgO): 32%;

[0048] ③ Calcium oxide (CaO): 0.5%;

[0049] ④ The remaining components are composed of impurities such as potassium oxide, sodium oxide, aluminum oxide, and iron oxide. The content of each single impurity does not exceed 0.2%;

[0050] The powder of the above combined composition is made into a tablet and placed in the base. Pressure is applied axially to the second fixing member 23, and the pressure is transmitted to the powder tablet. Under the action of the powder-breaking structure and pressure, the powder density gradually increases, so that the ceramic chip core is clamped and does not fall off. Since the powder density gradually increases when an external force is applied, it is avoided to cause damage to the ceramic chip core due to impact; in addition, since the powder density is relatively large, it can play a sealing role, and the sealing performance can also be further improved by high-temperature sintering. The gas leakage rate ≤ 0.2 ml / min. Of course, the powder tablet 22 of the present application is not limited to the above composition, and those skilled in the art can also select other powder materials that can achieve the above functions.

[0051] The above is the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A gas sensor ceramic chip installation protection structure, characterized in that: Including exhaust hood, base, metal protective sleeve, rubber sealing plug; Wherein, the exhaust hood is connected to the base, and the exhaust hood includes an outer hood and an inner hood arranged inside the outer hood, the end surface of the outer hood is provided with an outer air unit connected with the inner part of the outer hood at the axial position, and the end surface of the outer hood is also provided with a plurality of first air inlet holes around the outer air unit; the top end of the outer air unit is provided with a first air outlet hole; the end surface of the inner hood is provided with an inner air outlet unit connected with the inner part of the inner hood, the inner air outlet unit is arranged inside the outer air unit, and the top end of the inner air outlet unit is provided with a plurality of second air outlet holes, and the second air outlet holes are staggered with the first air outlet holes and have no overlap; the side wall of the inner hood is provided with a plurality of second air inlet holes; The base is connected to the metal protective sleeve, and the inner hole of the base is provided with a first fixing part, a powder tablet, and a second fixing part in sequence from the inside to the outside. The first fixing part, the powder tablet, and the second fixing part are all provided with a core through hole. The ceramic core passes through the first fixing part, the powder tablet, and the core through hole of the second fixing part arranged in the base. The first fixing part and the second fixing part are provided with a first powder breaking structure and a second powder breaking structure at the end in contact with the powder tablet. The first powder breaking structure and the second powder breaking structure are used to fully break the powder tablet when axial pressure is applied, and to re-compact the broken powder to fix the ceramic core; the second fixing part is a stepped structure, including an insertion base The thick part of the inner hole and the thin part exposed on the outside of the base, the base is provided with an edge deformation fixing part at a position opposite to the connection between the thick part and the thin part of the second fixing part, and the second fixing part is fixed by the deformation of the edge deformation fixing part; the thin part is provided with a terminal mounting hole connected to the core via hole at one end close to the metal protective sleeve, and a wiring terminal connected to the ceramic core is installed in the terminal mounting hole, and the wire at the other end of the wiring terminal extends into the metal protective sleeve; a rubber sealing plug is installed in the inner hole at the tail end of the metal protective sleeve, and the rubber sealing plug is provided with wire via holes matching the number of wires, and the rubber sealing plug is fixed by riveting the metal protective sleeve.

2. A gas sensor ceramic chip installation protection structure according to claim 1, characterized in that: The outer cover and the inner cover are transitionally or interference-fitted; the exhaust cover is installed at one end of the base by welding, and the metal protection sleeve is installed at the other end of the base by welding.

3. A gas sensor ceramic chip installation protection structure according to claim 1, characterized in that: The outer surface of the base is provided with an external thread at a position close to the exhaust hood, and a hexagonal matching portion is provided at a position close to the metal protection sleeve; the inner hole of the base close to the external thread end is designed as a conical hole.

4. A gas sensor ceramic chip installation protection structure according to claim 1, characterized in that: A wire harness protection sleeve is arranged outside the wire extending to the outside of the metal protection sleeve, and the other end of the wire is connected to a connector.

5. A gas sensor ceramic chip installation protection structure according to claim 1, characterized in that: The first fixing member and the second fixing member are both ceramic members, and the first fixing member is provided with an enlarged hole at a position close to the external leakage end of the ceramic core; the powder breaking structure at the end of the first fixing member is arranged on both sides of the core through hole, and is a structure protruding from the end face of the first fixing member and having a flat contact surface with the powder tableting surface; the powder breaking structure of the second fixing member is a structure protruding from the end face of the second fixing member and having a flat contact surface with the powder tableting surface.

6. A gas sensor ceramic chip installation protection structure according to claim 1, characterized in that: The plurality of first air inlet holes are arranged at equal intervals around the external air outlet unit, and the plurality of second air outlet holes are distributed at equal intervals around the first air outlet; the first air outlet, the second air outlet and the first air inlet hole are all circular, and the inner diameter of the first air outlet is larger than the inner diameter of the second air outlet; the second air inlet hole is crescent-shaped or semicircular, and the crescent-shaped or semicircular second air inlet hole is arranged obliquely, forming an acute angle with the axis of the gas sensor.

7. A gas sensor ceramic chip installation protection structure according to claim 1, characterized in that: The outer end surface of the detail is also provided with a marking hole, and the marking hole is used to identify the assembly direction.

8. A gas sensor ceramic chip installation protection structure according to claim 5, characterized in that: The enlarged hole is a circular hole, a rectangular hole or a square hole.

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