Protective shell of gas sensor and gas sensor

Abstract

The gas sensor comprises a carrier and a measurement chip arranged on the carrier, the protection shell is used for being installed on the carrier to cover the measurement chip, a measurement cavity used for containing the measurement chip is formed in the protection shell, an outer air inlet hole is formed in the side wall of the protection shell, and the outer air inlet hole is communicated with the measurement cavity. Measurement gas can enter the measurement cavity through the outer gas inlet hole, the top wall of the protection shell is provided with an inner concave part which is concave inwards from the top wall, the inner concave part is connected to the top wall and is separated from the measurement chip, a blocking cavity is formed between the inner concave part and the top wall, and the inner concave part is provided with an inner gas outlet hole communicating with the measurement cavity and the blocking cavity. The top wall is further provided with an outer air outlet hole, and measured air can enter the blocking cavity from the measuring cavity through the inner air outlet hole and leave the protective shell from the blocking cavity through the outer air outlet hole. The gas sensor solves the problem that the gas sensor in the prior art is unreasonable in structural design, so that the detection chip is easy to contact with water vapor, and the cracking risk is high.

Description

Technical Field

[0001] The utility model belongs to the technical field of gas sensors, and in particular relates to a protective shell of a gas sensor and a gas sensor. Background Art

[0002] The gas sensor installed in the exhaust system (exhaust pipe) of the car is used to measure the gas concentration (content) of the exhaust system. The exhaust gas of the exhaust system usually contains water vapor. The gas sensor needs to heat itself to about 800℃ and keep the temperature constant when working. If the water vapor condenses into water and hits the high-temperature detection chip of the gas sensor, it will cause the detection chip to crack and fail.

[0003] The structure of the detection part of an existing gas sensor usually includes: a detection chip and a double-layer protective shell (inner shell and outer shell) covering the detection chip. The inner shell directly covers the detection chip and forms a measurement chamber; the outer shell covers the inner shell, and a gas buffer chamber is formed between the outer shell and the inner shell. The gas enters the buffer chamber from the outer air inlet hole on the side wall of the sensor shell, and then enters the measurement chamber through the inner air inlet hole on the side wall of the inner shell. The detection chip detects the gas entering the measurement chamber. During this process, the water vapor in the gas will be difficult to condense into water due to the high temperature, and the water vapor is difficult to contact the high-temperature detection chip.

[0004] However, in actual use, it was found that a small amount of water vapor in the exhaust gas might enter the measuring chamber through the air vent on the top of the outer shell. Since the detection chip is usually directly below the air vent, the detection chip is directly exposed to water vapor through the air vent. As a result, it is easy for water vapor to enter the measuring chamber through the air vent and contact the detection chip, resulting in the risk of cracking of the detection chip. Utility Model Content

[0005] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a protective shell for a gas sensor and a gas sensor, so as to solve the problem that the gas sensor structure design in the prior art is unreasonable, which makes the detection chip easily exposed to water vapor, resulting in a higher risk of cracking.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A protective shell of a gas sensor, the gas sensor comprising a carrier and a measuring chip arranged on the carrier, the protective shell being used to be installed on the carrier to cover the measuring chip,

[0008] A measuring chamber for accommodating the measuring chip is formed in the protective shell.

[0009] The side wall of the protective shell is provided with an external air inlet hole, and the measurement gas can enter the measurement chamber through the external air inlet hole.

[0010] The top wall of the protective shell is provided with an inner concave portion sunken from the top wall to the inside, the inner concave portion is connected to the top wall and is separated from the measuring chip, and a blocking chamber is formed between the inner concave portion and the top wall.

[0011] The inner concave portion is provided with an inner air outlet hole connecting the measuring chamber and the blocking chamber, and the top wall is also provided with an outer air hole, so that the measuring gas can enter the blocking chamber from the measuring chamber through the inner air outlet hole, and leave the protective shell from the blocking chamber through the outer air hole.

[0012] The inner recessed portion can prevent water vapor entering the barrier chamber from the outgoing air hole from entering the measuring chamber.

[0013] As an embodiment of the utility model, the setting position of the internal air outlet and the position of the measuring chip are staggered in the axial direction; and / or there are multiple internal air outlets, and when viewed from above, the multiple internal air outlets are arranged in the inner recess around the measuring chip.

[0014] As an embodiment of the utility model, the inner recess includes a recess side wall and a recess bottom wall, the top end of the recess side wall is fixedly connected to the top wall, and the inner air outlet is arranged on the recess side wall and / or the recess bottom wall.

[0015] As an embodiment of the present utility model, the top wall has an outer convex portion formed to protrude in a direction away from the inner concave portion, the outgoing air hole is provided in the outer convex portion, and the barrier chamber is formed between the outer convex portion and the inner concave portion.

[0016] As an implementation mode of the utility model, the inner recessed portion is formed into a bowl-shaped structure with an inverted trapezoidal cross section.

[0017] As an implementation mode of the present utility model, the outer concave portion is formed as an inverted bowl-shaped structure with a trapezoidal cross-section corresponding to the inner concave portion.

[0018] As an embodiment of the utility model, the protective shell includes an outer shell and an inner shell, the inner shell is sealed and connected to the outer shell in at least a partial area, a buffer chamber is formed between the side wall of the outer shell and the side wall of the inner shell, the measuring chamber is formed in the inner shell, and the side wall of the inner shell is provided with an inner air inlet hole connecting the buffer chamber and the measuring chamber, and the measuring gas can enter the buffer chamber through the outer air inlet hole and enter the measuring chamber through the inner air inlet hole.

[0019] As an embodiment of the utility model, the outer ring of the inner shell top wall is sealed and connected to the outer shell top wall, the inner shell top wall is recessed inward to form the inner concave portion, and the outer shell top wall is protruded outward to form an outer convex portion, and the barrier chamber is formed between the outer convex portion and the inner concave portion.

[0020] As an implementation manner of the utility model, the outer air inlet hole is arranged above the side wall of the outer shell, and the inner air inlet hole is arranged below the side wall of the inner shell.

[0021] As an implementation mode of the present utility model, the number of the outer air inlet holes is six and they are evenly distributed on the side wall of the outer shell along the circumferential direction; the number of the inner air inlet holes is six and they are evenly distributed on the side wall of the inner shell along the circumferential direction.

[0022] In order to achieve the above purpose, the utility model also adopts the following technical solutions:

[0023] A gas sensor comprises: a carrier, a measuring chip arranged on the carrier and the above-mentioned protective shell, wherein the protective shell is installed on the carrier to cover the measuring chip.

[0024] The utility model can block the water vapor from further invading the measuring chip through the inner concave part when the water vapor intrudes into the interior of the gas sensor from the outgoing air hole, thereby reducing the risk of the measuring chip bursting. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 It is a partial front cross-sectional view of a gas sensor of a specific embodiment of the utility model;

[0027] Figure 2 This is a structural stereogram of a housing of a gas sensor according to a specific embodiment of the utility model;

[0028] Figure 3 It is a structural stereogram of the inner shell of a gas sensor of a specific embodiment of the utility model;

[0029] Figure 4 It is a front view of the inner shell of the gas sensor of a specific embodiment of the utility model;

[0030] Figure 5 It is a top view of the inner shell of the gas sensor of a specific embodiment of the utility model;

[0031] Figure 6 is a top cross-sectional view of a gas sensor according to a specific embodiment of the utility model;

[0032] Figure 7 This is a schematic diagram of the gas flow of the measuring gas in the protective shell of the gas sensor of a specific embodiment of the utility model;

[0033] Figure 8 It is a partial front cross-sectional view of a gas sensor according to another specific embodiment of the utility model.

[0034] Description of reference numerals:

[0035] 1. housing, 11. external air inlet, 12. external air outlet, 13. external bottom mounting opening, 14. buffer chamber, 15. housing top wall, 16. external convex portion;

[0036] 2. inner shell, 21. inner air inlet, 211. flow guide, 22. inner recess, 221. recess side wall, 222. recess bottom wall, 223. inner air outlet, 23. inner bottom mounting port, 24. measuring chamber, 25. inner shell top wall;

[0037] 3. measuring chip, 34. barrier chamber;

[0038] 4. carrier, 41. first boss, 42. second boss;

[0039] W1, first width, W2, second width, Φ, diameter. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the utility model, and are not used to limit the utility model.

[0041] In the present utility model, unless otherwise specified, directional words such as "up", "down", "left", "right", "front" and "back" generally refer to the up, down, left and right of the device in actual use or working state, specifically the drawing direction in the accompanying drawings.

[0042] It should be noted that the description order of the following embodiments is not intended to limit the preferred order of the embodiments of the present application. In addition, in the following embodiments, the description of each embodiment has its own emphasis, and for parts not described in detail in one embodiment, reference can be made to the relevant description of other embodiments.

[0043] The utility model is based on a gas sensor, specifically, is an improvement and innovation based on a nitrogen oxide sensor. Since the nitrogen oxide sensor is installed in the exhaust system of a car, the gas flow rate of the exhaust system is very fast, which will cause the detector to be unable to accurately detect the content of the gas (nitrogen oxides), and the detector needs to heat itself to 800°C and keep the temperature constant when working. In addition, the exhaust gas contains water vapor. The existing design has an air outlet just above the head of the chip. Theoretically, no water vapor will enter the air outlet according to the Venturi effect. However, in actual use, it is found that a small amount of water vapor will still enter. Because the chip is underneath, it is equivalent to the chip being directly exposed to water vapor. The chip will be at risk of bursting if it comes into contact with water vapor under high temperature.

[0044] The utility model provides a gas sensor, which can prevent water vapor from directly entering from the air outlet and directly contacting the chip in the high temperature state. Specifically, the gas sensor includes: a carrier, a measuring chip arranged on the carrier, and a protective shell, the protective shell is installed on the carrier of the gas sensor to cover the measuring chip, the gas sensor is installed in the automobile exhaust system, and is used to detect the concentration (content) of the gas in the automobile exhaust system, and the protective shell is used to prevent the measuring chip from directly contacting the high-flow gas and water vapor in the automobile exhaust system, thereby preventing the measurement accuracy of the gas sensor from being reduced and the measuring chip from cracking.

[0045] like Figures 1 to 6 As shown, in a specific embodiment, the protective shell includes an outer shell 1 and an inner shell 2 arranged in the outer shell 1, and the inner shell 2 is sealed to the outer shell 1 in at least a partial area. For example, the inner shell top wall 25 of the inner shell 2 may be sealed to the outer shell top wall 15 of the outer shell 1.

[0046] The measuring chip 3 is arranged in the inner shell 2, so that the inner shell 2 covers the measuring chip 3, an annular buffer chamber 14 is formed between the outer wall of the inner shell 2 and the inner wall of the outer shell 1, a measuring chamber 24 is formed in the inner shell 2, the inner shell top wall 25 of the inner shell 2 is recessed inward to form an inner recess 22, a blocking chamber 34 is formed between the outer shell top wall 15 of the outer shell 1 and the inner recess 22, the measuring chip 3 is accommodated in the measuring chamber 24 and is separated from the inner recess 22.

[0047] The side wall of the outer shell 1 is provided with an external air inlet 11 connecting the exhaust system of the automobile outside the outer shell 1 and the buffer chamber 14, so that the measuring gas in the exhaust system of the automobile can enter the buffer chamber 14 through the external air inlet 11; the side wall of the inner shell 2 is provided with an internal air inlet 21 connecting the buffer chamber 14 and the measuring chamber 24, and the measuring gas entering the buffer chamber 14 can enter the measuring chamber 24 through the internal air inlet 21, so that the measuring chip 3 in the measuring chamber 24 can detect the concentration (content) of the measuring gas.

[0048] like Figure 1 , Figure 3 and Figure 5 As shown, the housing top wall 15 is also provided with an outgoing air hole 12 connecting the blocking chamber 34 with the outside of the housing 1, and the inner concave portion 22 is provided with an inner air hole 223 connecting the measuring chamber 24 with the blocking chamber 34. When the measuring gas is detected by the measuring chip 3, it can enter the blocking chamber 34 through the inner air hole 223, and then the measuring gas leaves the gas sensor from the blocking chamber 34 through the outgoing air hole 12.

[0049] In addition, the inner recess 22 can also prevent water vapor entering the isolation chamber 34 from the external air hole 12 from entering the measurement chamber 24 and contacting the measurement chip 3 .

[0050] Further, the inner concave portion 22 includes a concave side wall 221 and a concave bottom wall 222 opposite to the measuring chip 3, and an inner gas outlet 223 is provided on the concave bottom wall 222. The inner gas outlet 223 is preferably arranged at a position staggered with the position of the measuring chip 3. The inner gas outlet 223 is arranged at the concave bottom wall 222 to facilitate the measuring gas to quickly leave the measuring chamber 24.

[0051] In a preferred embodiment, the inner air outlet 223 and the measuring chip 3 are staggered in the axial direction, that is, the inner air outlet 223 and the measuring chip 3 are not located in the same straight line in the axial direction, which can well ensure that water vapor does not contact the measuring chip 3 through the inner air outlet 223.

[0052] It is understandable that, since the inner air outlet 223 is staggered with the measuring chip 3, even if water vapor intrudes into the blocking chamber 34 from the outer air outlet 12 and into the measuring chamber 24 from the inner air outlet 223, the water vapor will not contact the measuring chip 3, but will fall from the periphery of the measuring chip 3. In the process of falling, it is evaporated by the high temperature of the gas sensor. Preferably, the inner concave portion 22 is formed into a bowl-shaped structure with an inverted trapezoidal cross section to facilitate the molding of the structure.

[0053] Therefore, the utility model provides an inner recess on the top wall of the inner shell, so that when water vapor invades the interior of the gas sensor from the outgoing air hole, the inner recess can block the water vapor from further invading the measuring chip, thereby reducing the risk of the measuring chip bursting. Specifically, when water vapor invades the interior of the gas sensor from the outgoing air hole, it will first invade the barrier chamber between the top wall of the outer shell and the inner recess, and then the high temperature of the gas sensor will evaporate the water vapor invading the barrier chamber into water vapor, thereby preventing the water vapor from entering the measuring chamber through the inner air hole. Compared with the existing structure in which the measuring chip is directly exposed to water vapor through the outgoing air hole, the utility model blocks the water vapor by providing an inner recess, ensuring that it is vaporized before further invading, thereby preventing it from contacting the measuring chip.

[0054] In addition, the utility model sets a double layer of air outlet holes (inner air outlet hole 223 and outer air outlet hole 12), and the barrier chamber formed between the two layers can be used as an air outlet buffer chamber, which can slow down the air outlet speed, thereby ensuring the stability of the air pressure in the measurement chamber and preventing the gas to be measured entering the test chamber from being quickly drawn away; and because the inner concave portion is formed inwardly on the top wall of the inner shell, it will not change the outer dimensions of the gas sensor, and also avoids the gas sensor from being enlarged.

[0055] In addition, through the protective shell of the gas sensor provided by the utility model, the high-flow rate measurement gas in the exhaust system passes through the outer shell 1, the buffer chamber 14 and the inner shell 2 in sequence and then enters the inner shell (measurement chamber 24), so that the airflow is blocked by the outer shell and the inner shell to reduce the speed and pressure, and then enters the measurement chamber, so that the gas flow rate reaches a steady state that can be detected, and then is detected by the measuring chip, thereby improving the measurement accuracy of the gas sensor (that is, the buffer chamber and the measuring chamber formed by the outer shell 1 and the inner shell 2 can stabilize the gas in the exhaust system, reduce the influence of the airflow on the measuring chip 3 during measurement, and ensure the measurement accuracy).

[0056] like Figure 1 As shown, in a specific embodiment, the inner shell 2 is sealed and connected to the outer shell 1 at least in part of the area, and the outer ring (preferably the outermost edge) of the inner shell top wall 25 can be sealed and connected to the outer shell top wall 15, and the inner ring of the inner shell top wall 25 is recessed inward to form an inner concave portion 22. Alternatively, the top of the side wall of the inner shell 2 is sealed and connected to the top of the side wall of the outer shell 1. As long as the air inlet area (buffer chamber 14) and the air outlet area (barrier chamber 34) of the gas sensor are sealed and separated, the utility model does not limit the specific sealing position of the inner shell and the outer shell.

[0057] Continue to refer to Figure 1 , Figure 3 and Figure 5 In a specific embodiment, a plurality of inner air outlet holes 223 are provided, and the plurality of inner air outlet holes 223 are arranged on the bottom wall 222 of the recess so as to surround the measuring chip 3 when viewed from above (i.e., the measuring chip 3 is surrounded by the plurality of inner air outlet holes 223 when viewed from above). In this way, while preventing the measuring chip from contacting water vapor, it is possible to ensure that normal measuring gas can flow out of the gas sensor faster, and prevent excessive measuring gas from accumulating in the test cavity and affecting the measuring accuracy of the gas sensor. Preferably, four or more inner air outlet holes 223 are provided. More preferably, the distance W2 between two facing inner air outlet holes 223 is preferably 3 mm, and the diameter of the inner air outlet hole 223 is preferably Φ0.8 mm.

[0058] In addition, multiple inner air outlet holes 223 may be disposed on the concave sidewall 221, or multiple inner air outlet holes 223 may be disposed on both the concave sidewall 221 and the concave bottom wall 222. The present invention does not limit the location of the inner air outlet holes 223 on the inner concave.

[0059] like Figure 1 and Figure 2 As shown, the top wall 15 of the outer shell has an outer convex portion 16 opposite to the inner concave portion 22. Specifically, the outer ring of the outer shell top wall 15 is sealed and connected to the outer ring of the inner shell top wall 25, and the inner ring of the outer shell top wall 15 protrudes outward to form the outer convex portion 16. The outgoing air hole 12 is provided on the outer convex portion 16, and a barrier chamber 34 is formed between the outer convex portion 16 and the inner concave portion 22. Therefore, by forming the outer convex portion 16 on the top wall 15 of the outer shell, the height of the barrier chamber 34 is increased, that is, the movement path of the water vapor after invading the barrier chamber 34 from the outgoing air hole 12 can be lengthened, so that the gas sensor can have more time to evaporate the water vapor, and prevent the water vapor from continuing to invade downwards without evaporation. Preferably, the outer convex portion 16 is formed as an inverted bowl-shaped structure with a trapezoidal cross-section to facilitate the molding of the structure.

[0060] like Figure 1 , Figure 3 , Figure 4 and Figure 6 As shown, further, the inner air inlet 21 is provided with a guide portion 211 extending toward the inner shell, and the guide portion 211 is used to guide the measurement gas along a preset path into the measurement chamber 24. Thus, the measurement gas is guided to flow along the preset path in a prescribed gas flow direction by the guide portion 211, so as to prevent the measurement gas from generating a chaotic airflow in the measurement chamber to affect the measurement accuracy, thereby improving the measurement accuracy of the gas sensor.

[0061] like Figure 1 As shown, in a specific embodiment, the outer air inlet 11 and the inner air inlet 21 are staggered along the axial direction of the protective shell (for the convenience of illustration, Figure 1 The outer air inlet 11 and the inner air inlet 21 shown in the figure are parallel to the axial direction). Preferably, the outer air inlet 11 is arranged above the side wall of the outer shell 1, and the inner air inlet 21 is arranged below the side wall of the inner shell 2. In this way, it can be ensured that the measuring gas can be blocked by the inner shell 2 and reduce speed and pressure after entering the buffer chamber 14 from the outer air inlet 11. Specifically, the outer air inlet 11 is close to the top of the protective shell in the axial direction, and the inner air inlet 21 is close to the bottom of the protective shell in the axial direction, so that the distance between the outer air inlet 11 and the inner air inlet 21 in the axial direction is longer, so that the measuring gas can flow from top to bottom in the buffer chamber 14, so that the measuring gas enters the measuring chamber 24 after traveling a longer distance in the buffer chamber 14, thereby reducing the flow rate and pressure of the measuring gas when entering the measuring chamber 24.

[0062] In a preferred embodiment, there are six outer air inlet holes 11 and they are evenly distributed on the side wall of the outer shell 1 along the circumferential direction; there are also six inner air inlet holes 21 and they are evenly distributed on the side wall of the inner shell 2 along the circumferential direction. 。 More preferably, the six outer air inlet holes 11 and the six inner air inlet holes 21 are arranged to be staggered with each other in the circumferential direction (that is, the six outer air inlet holes 11 and the six inner air inlet holes 21 are arranged not in a straight line in the axial direction), thereby further extending the distance between the outer air inlet holes 11 and the inner air inlet holes 21. Thus, the travel distance of the measurement gas in the buffer chamber 14 is further increased, thereby further reducing the flow rate and pressure of the measurement gas when entering the measurement chamber 24.

[0063] Reference Figure 4 and Figure 6 In a specific embodiment, the guide portion 211 is an inclined flange folded from one side of the radial direction of the inner air inlet 21 to the inner shell. When the measuring gas enters the measuring chamber 24 from the buffer chamber 14 through the inner air inlet 21, it is blocked by the inclined flange, and the airflow direction of the measuring gas is changed to be along a preset path (i.e., Figure 7 The measured gas flows in a spiral shape around the measuring chip 3 through the guide portion 211 (inclined flange), and enters the measuring chamber (in a spiral shape around the circumferential direction) and flows out from the gas outlet 12 after being detected by the measuring chip 3. Thus, the measuring gas flows in a spiral shape around the measuring chip 3 through the guide portion 211 (inclined flange), and the measuring chip 3 can be prevented from being impacted by the high-speed chaotic airflow during measurement, which affects the measurement accuracy (i.e., further improves the measurement accuracy of the measuring chip).

[0064] In a preferred embodiment, the folding angle of the inclined flange is 45°, so as to ensure the air intake and at the same time ensure that the measuring gas flows in a spiral shape in the measuring chamber.

[0065] In a specific embodiment, the outer air inlet hole 11 is preferably a circular hole to ensure the air intake; the inner air inlet hole 21 is preferably a square hole. Compared with the circular hole, the square hole has a larger resistance value due to the existence of its four corners, and therefore can ensure the pressure reduction and speed reduction effect.

[0066] In a specific embodiment, the inclined flange is folded inwardly of the inner shell from the side of the square hole parallel to the axial direction.

[0067] In a preferred embodiment, if Figure 6 As shown, the opening width W1 between the inner air inlet hole 21 and the guide portion 211 (the inclined flange) is 0.42 mm to 0.62 mm.

[0068] In another specific embodiment, the guide portion 211 is a guide tube (not shown) disposed at the inner air inlet hole 21 and extending obliquely into the inner shell. When the measuring gas enters the measuring chamber 24 from the buffer chamber 14 through the inner air inlet hole 21, it is guided by the guide tube, and the airflow direction of the measuring gas is changed to enter the measuring chamber in a spiral shape around the circumferential direction, and then flows out from the air outlet 12 after detection by the measuring chip 3.

[0069] Reference Figure 1 The gas sensor further includes a carrier 4, a measuring chip 3 is arranged in the carrier 4, and the protective shell is installed on the carrier 4 and covers the measuring chip 3. Specifically, the bottom of the outer shell 1 has an outer bottom mounting opening 13, and the bottom of the inner shell 2 has an inner bottom mounting opening 23. The protective shell can be sealed and connected to the carrier 4 through the outer bottom mounting opening 13 and the inner bottom mounting opening 23. A second boss 42 corresponding to the outer bottom mounting opening 13 and a first boss 41 corresponding to the inner bottom mounting opening 23 and arranged above the second boss 42 are provided above the carrier 4. The outer bottom mounting opening 13 is embedded in the second boss 42 and sealed by laser welding, and the inner bottom mounting opening 23 is embedded in the first boss 41 and sealed by laser welding.

[0070] In a specific embodiment, the measuring chip 3 is supported in the through hole of the carrier 4 by a plurality of supporting blocks (not shown), and the detection end of the measuring chip 3 extends out of the through hole.

[0071] like Figure 8As shown, in another specific embodiment, the protective shell of the gas sensor may not include the inner shell 2, and is only installed on the carrier 4 and covers the measuring chip 3 through the outer shell 1. In this case, the outer shell 1 is equivalent to the protective shell of the gas sensor, and the inner recess is a bowl-shaped structure installed on the top wall of the protective shell (the outer shell top wall 15). Specifically, a measuring chamber 24 for accommodating the measuring chip is formed in the protective shell, and the measuring chip 3 is accommodated in the measuring chamber 24 and is separated from the top wall of the protective shell (the outer shell top wall 15); an inner recess 22 is provided in the protective shell (the outer shell 1), and the inner recess 22 is connected to the top wall of the protective shell (the outer shell top wall 15) and is separated from the measuring chip 3, and a blocking chamber 34 is formed between the inner recess 22 and the top wall of the protective shell (the outer shell top wall 15). The side wall of the protective shell (shell 1) is provided with an external air inlet 11 connecting the outside of the protective shell (shell 1) (the exhaust system of the car) and the measuring chamber 24. The measuring gas in the exhaust system can enter the measuring chamber 24 through the external air inlet 11, so that the measuring chip 3 in the measuring chamber 24 can detect the concentration (content) of the measuring gas; the inner concave portion 22 is provided with an inner air outlet 223 connecting the measuring chamber 24 and the barrier chamber 34. After being detected by the measuring chip 3, the measuring gas can enter the barrier chamber 34 through the inner air outlet 223; the top wall of the protective shell (the top wall of the shell 15) is also provided with an outgoing air hole 12 connecting the barrier chamber 34 and the outside of the shell 1. The measuring gas leaves the barrier chamber 34 through the outgoing air hole 12, wherein the inner concave portion 22 is also used to prevent water vapor entering the barrier chamber 34 from the outgoing air hole 12 from entering the measuring chamber 24 and contacting the measuring chip 3.

[0072] Therefore, the utility model can block the water vapor from entering the measuring chip when the water vapor enters the gas sensor from the outgoing vent, thereby reducing the risk of the measuring chip bursting. It should be noted that the inner shell of the utility model is used to reduce the gas flow rate. Even if the inner shell is not provided, and only the inner concave portion for blocking water vapor is provided on the outer shell, the utility model can also achieve the effect of reducing the risk of the measuring chip bursting.

[0073] In addition, in this embodiment, only the inner shell is eliminated, and the other structures are the same as those of the above-mentioned embodiment, so the same effect can be achieved.

[0074] The scheme of the present application is introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

[0075] References throughout the specification to "one embodiment," "an embodiment," or "a specific embodiment" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present application, and not necessarily in all embodiments. Thus, various appearances of the phrases "in one embodiment," "in an embodiment," or "in a specific embodiment" in different places throughout the specification do not necessarily refer to the same embodiment. In addition, the particular features, structures, or characteristics of any specific embodiment of the present application may be combined with one or more other embodiments in any suitable manner. It should be understood that other variations and modifications of the embodiments of the application described and illustrated herein may be based on the teachings herein and will be considered part of the spirit and scope of the present application.

[0076] It should also be understood that one or more of the elements shown in the figures may also be implemented in a more separate or more integrated manner, or even removed because they are inoperable in certain circumstances or provided because they may be useful depending on the application.

[0077] In addition, unless otherwise explicitly indicated, any marking arrows in the drawings should be regarded as exemplary only and not limiting. In addition, unless otherwise indicated, the term "or" used herein is generally intended to mean "and / or". In the case where the term is not clear because it is anticipated that the ability to separate or combine is provided, the combination of components or steps will also be regarded as indicated.

Claims

1. A protective shell of a gas sensor, the protective shell is used to cover a measuring chip of the gas sensor, characterized in that: A measuring chamber for accommodating the measuring chip is formed in the protective shell. The side wall of the protective shell is provided with an external air inlet hole, and the measurement gas can enter the measurement chamber through the external air inlet hole. The top wall of the protective shell is provided with an inner concave portion sunken from the top wall to the inside, the inner concave portion is connected to the top wall and is separated from the measuring chip, and a blocking chamber is formed between the inner concave portion and the top wall. The inner recessed portion is provided with an inner air outlet hole connecting the measuring chamber and the barrier chamber, and the top wall is also provided with an outer air outlet hole, so that the measuring gas can enter the barrier chamber from the measuring chamber through the inner air outlet hole, and leave the protective shell from the barrier chamber through the outer air outlet hole.

2. The protective case according to claim 1, characterized in that: The arrangement position of the inner air outlet and the position of the measuring chip are staggered in the axial direction; and / or There are a plurality of inner air outlet holes, and the plurality of inner air outlet holes are arranged in the inner recessed portion around the measuring chip when viewed from above.

3. The protective case according to claim 1, characterized in that: The inner recess comprises a recess side wall and a recess bottom wall, the top end of the recess side wall is fixedly connected to the top wall, and the inner air outlet is arranged on the recess side wall and / or the recess bottom wall.

4. The protective shell according to any one of claims 1 to 3, characterized in that: The top wall has an outer convex portion formed to protrude in a direction away from the inner concave portion, the outgoing air hole is provided in the outer convex portion, and the blocking chamber is formed between the outer convex portion and the inner concave portion.

5. The protective case according to claim 4, characterized in that: The inner concave portion is formed into a bowl-shaped structure with an inverted trapezoidal cross section.

6. The protective case according to claim 1, characterized in that: The protective shell comprises an outer shell and an inner shell, wherein the inner shell is sealed and connected to the outer shell at least in a partial area. A buffer chamber is formed between the side wall of the outer shell and the side wall of the inner shell, and the measuring chamber is formed in the inner shell. The side wall of the inner shell is provided with an inner air inlet hole connecting the buffer chamber and the measuring chamber, and the measuring gas can enter the buffer chamber through the outer air inlet hole and enter the measuring chamber through the inner air inlet hole.

7. The protective case according to claim 6, characterized in that: The outer ring of the inner shell top wall is sealed with the outer shell top wall, the inner shell top wall is recessed inward to form the inner concave portion, and the outer shell top wall is protruded outward to form the outer convex portion. The blocking chamber is formed between the outer convex portion and the inner concave portion.

8. The protective shell according to claim 6 or 7, characterized in that: The outer air inlet hole is arranged above the side wall of the outer shell, and the inner air inlet hole is arranged below the side wall of the inner shell.

9. The protective case according to claim 8, characterized in that: There are six outer air inlet holes which are evenly distributed on the side wall of the outer shell along the circumferential direction; there are six inner air inlet holes which are evenly distributed on the side wall of the inner shell along the circumferential direction.

10. A gas sensor, characterized in that: include: A carrier, a measuring chip arranged on the carrier, and a protective shell according to any one of claims 1 to 9, wherein the protective shell is mounted on the carrier to cover the measuring chip.

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