Protective shell of gas sensor and gas sensor

Abstract

The protective shell is used for covering a measuring chip of the gas sensor, the protective shell comprises an outer shell and an inner shell arranged on the radial inner side of the side wall of the outer shell, at least part of the inner shell is in sealed connection with the outer shell, and the inner shell is used for covering the measuring chip. A first cavity is formed between the inner wall of the outer shell and the outer wall of the inner shell; a second cavity for accommodating the measuring chip is formed in the inner shell, and an outer air inlet hole for communicating the outside of the outer shell with the first cavity is formed in the side wall of the outer shell; the side wall of the inner shell is provided with an inner air inlet hole communicated with the first cavity and the second cavity, the protective shell is also provided with an air outlet part, and the protective shell is also internally provided with a buffer part for preventing the measurement gas entering the first cavity and / or the second cavity from flowing. The gas sensor solves the problems that in the prior art, the gas flow rate and pressure are difficult to stabilize, and the measurement precision of the gas sensor is low.

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 concentration (content) of the gas in the exhaust system (mainly refers to the exhaust gas of the car). The gas flow rate of the exhaust system is very fast, which will cause the gas sensor to be unable to accurately detect the content of the gas (nitrogen oxides), and the sensor needs to heat itself to 800℃ and keep the temperature constant when working. In addition, the exhaust gas contains water vapor. For the above reasons, if the sensor's detection head is directly exposed to the outside, there will be problems such as detection failure and explosion when exposed to water.

[0003] In view of the above problems, the current solution is to cover the sensor's detection head with a double-layer protective cover to prevent the detection head from being exposed to the outside and directly contacting water vapor and gas with a faster flow rate. For example, Chinese utility model patent CN207764190U discloses a gas sensor, which covers the gas detection element with an outer shell and an inner shell, and the gas flows into the inner shell through the first gas flow port, the gas flow channel and the inner shell hole. However, the protective cover of the inner and outer shell double-layer structure of the above-mentioned prior art has only a double-layer structure. After the gas enters from the outer shell, only the inner layer of the inner shell plays a role in reducing and blocking the gas flow rate. This double-layer protective cover has little effect on stabilizing the gas flow rate and pressure, and it is difficult to achieve the expected effect when stopping the gas. When the gas flow rate changes, the measured value will fluctuate with the change of the flow rate, and when the fluctuation exceeds the allowable deviation range, it will lead to a decrease in measurement accuracy. Therefore, the gas sensor protective cover of the prior art is difficult to stabilize the gas flow rate and pressure, affecting the measurement accuracy of the gas sensor. Utility Model Content

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the utility model is to provide a protective shell of a gas sensor and a gas sensor, so as to solve the problem that the gas sensor of the prior art is difficult to stabilize the gas flow rate and pressure and the measurement accuracy of the gas sensor is low.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] 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, wherein:

[0007] The protective shell comprises: an outer shell and an inner shell arranged radially inwardly of a side wall of the outer shell, wherein the inner shell is sealed and connected to the outer shell at least in a partial area, and the inner shell is used to cover the measuring chip.

[0008] A first chamber is formed between the inner wall of the outer shell and the outer wall of the inner shell; a second chamber for accommodating the measuring chip is formed in the inner shell.

[0009] The side wall of the outer shell is provided with an external air inlet hole connecting the outside of the outer shell and the first chamber, and the measurement gas can enter the first chamber through the external air inlet hole; the side wall of the inner shell is provided with an internal air inlet hole connecting the first chamber and the second chamber, and the measurement gas can enter the second chamber from the first chamber through the internal air inlet hole.

[0010] The protective shell is also provided with a gas outlet for guiding the measured gas to flow out of the protective shell, wherein

[0011] A buffer portion is further provided in the protective shell, and the buffer portion is used to hinder the flow of the measurement gas entering the first chamber and / or the second chamber to reduce its flow velocity and / or flow rate.

[0012] As an embodiment of the utility model, the buffer portion is at least one concave ring formed by a local radial inward depression of the side wall of the outer shell, and / or the buffer portion is at least one convex ring arranged on the outer wall of the inner shell and / or the inner wall of the outer shell, and the concave ring and / or the convex ring are used to reduce the local width of the first chamber to reduce the flow rate and flow of the measuring gas entering the first chamber.

[0013] As an implementation manner of the present utility model, the inner concave ring and / or the convex ring is closer to the inner air inlet hole than to the outer air inlet hole.

[0014] As an implementation mode of the present utility model, the inner concave ring and / or the convex ring is tightly attached to the upper end of the inner air inlet hole in the axial direction.

[0015] As an implementation manner of the present invention, the width of the buffer portion is approximately half of the width of the first chamber.

[0016] As an embodiment of the present invention, the buffer portion also includes a buffer sleeve, which is arranged in the second chamber between the inner shell and the measuring chip to change the movement path of the measuring gas entering the second chamber to guide the measuring gas to the measuring end of the measuring chip.

[0017] As an embodiment of the utility model, the buffer sleeve includes a small diameter section and a large diameter section located below the small diameter section, the outer wall of the large diameter section is sealedly connected to the inner wall of the bottom of the inner shell, a guide channel is formed between the outer wall of the small diameter section and the inner wall of the inner shell, and the measuring end of the measuring chip extends out of the top opening of the buffer sleeve.

[0018] As an embodiment of the utility model, the air outlet portion includes: an air outlet hole provided at the top of the outer shell and connecting the second chamber with the outside of the outer shell, and a top opening provided at the top of the inner shell, the top of the inner shell extends longitudinally upward to the top of the outer shell and is sealed and connected to the top of the outer shell to form the top opening.

[0019] As an embodiment of the utility model, the top of the outer shell is formed as a truncated cone-shaped top boss protruding outward from the second chamber, and the top of the inner shell extends to the hypotenuse of the top boss and is sealed and connected with the hypotenuse to form the top opening.

[0020] As an implementation manner of the utility model, the outer shell has an outer bottom opening, the inner shell has an inner bottom opening, and the inner bottom opening and the outer bottom opening are sealed and connected to the carrier.

[0021] In order to achieve the above purpose, the utility model also adopts the following technical solutions:

[0022] 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.

[0023] The utility model provides a buffer portion to reduce the speed and pressure of the measurement gas entering the gas sensor and reduce the intake volume, so that the gas entering the gas sensor reaches a steady state that is convenient for detection by the measurement chip, thereby improving the measurement accuracy of the gas sensor; the utility model realizes that the gas sensor can work stably in the exhaust system and its service life reaches the expected design requirements through the structural design and optimization of the protective shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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.

[0025] Figure 1 It is a partial cross-sectional view of a gas sensor of a specific embodiment of the utility model;

[0026] Figure 2 This is a structural stereogram of a housing of a gas sensor according to a specific embodiment of the utility model;

[0027] Figure 3 It is a structural stereogram of the inner shell of a gas sensor of a specific embodiment of the utility model;

[0028] Figure 4 This is a structural stereogram of a buffer sleeve of a gas sensor according to a specific embodiment of the utility model;

[0029] Figure 5 is a diagram showing the size and mutual spacing of various structures in a gas sensor of a specific embodiment of the utility model;

[0030] Figure 6 The utility model is a schematic diagram of the gas flow of the measuring gas in the protective shell of the gas sensor in a specific embodiment.

[0031] Description of reference numerals:

[0032] 1. outer shell, 11. external air inlet, 12. air outlet, 13. outer bottom mounting opening, 14. first chamber, 15. top boss, 16. inner concave ring;

[0033] 2. inner shell, 21. inner air inlet, 22. top opening, 23. inner bottom mounting opening, 24. second chamber, 25. connecting flange;

[0034] 3. buffer sleeve, 31. small diameter section, 32. large diameter section, 33. sleeve top opening, 34. guide channel;

[0035] 4. carrier, 41. first boss, 42. second boss;

[0036] 5. measuring chip, 51. measuring end;

[0037] Aperture: Φ1, Φ2, Φ3;

[0038] Spacing: W1, W2, W3, W4, W5, W6. DETAILED DESCRIPTION

[0039] 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.

[0040] 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.

[0041] 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.

[0042] A specific embodiment of the utility model provides a gas sensor, which includes a protective shell and a measuring chip. The protective shell is used to cover the measuring chip of the gas sensor. The gas sensor is used to be installed in an automobile exhaust system to detect the concentration (content) of the gas (i.e., nitrogen oxides in the exhaust gas) in the automobile exhaust system. 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 avoiding a reduction in measurement accuracy.

[0043] like Figures 1 to 5 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, the inner shell 2 is sealed and connected to the outer shell 1 at least in a part of the area (for example, the top sealing connection is achieved through the connection flange 25 of the top boss 15 of the outer shell 1 and the top of the inner shell 2, and the bottom sealing connection is achieved through the boss of the carrier 4, which is described later), and the measuring chip 5 is supported in the inner shell 2 by the carrier 4 and the support block described later (specifically, the end away from the measuring end 51 is fixed in the carrier 4 by the support block, and the end close to the measuring end 51 is supported in the inner shell 2), so that the measuring chip 5 is covered by the inner shell 2; the inner shell 2 is sleeved in the outer shell 1 at intervals, so as to form an annular first chamber 14 between the outer wall of the inner shell 2 and the inner wall of the outer shell 1; a second chamber is formed in the inner shell 2 24, the measuring chip 5 is arranged in the second chamber 24, preferably in the center of the second chamber 24; the side wall of the outer shell 1 is provided with an outer air inlet 11 connecting the outside of the outer shell 1 (for example, the exhaust pipe of the car) and the first chamber 14, and the measuring gas in the exhaust pipe can enter the first chamber 14 through the outer air inlet 11; the side wall of the inner shell 2 is provided with an inner air inlet 21 connecting the first chamber 14 and the second chamber 24, and the measuring gas entering the first chamber 14 can enter the second chamber 24 through the inner air inlet 21, so that the measuring chip 5 in the second chamber 24 detects the concentration (content) of the measuring gas; in addition, the protective shell is also provided with an air outlet (i.e., the air outlet 12 and the top opening 22 described later), and the measuring gas leaves the protective shell through the air outlet after being detected by the measuring chip 5. Thus, the gas detection is completed. In addition, a buffer is also provided in the protective shell, and the buffer is used to hinder the flow of the measuring gas entering the first chamber 14 and / or the second chamber 24 to reduce its flow rate and / or flow rate.

[0044] like Figure 1 and Figure 2As shown, further, the buffer portion includes: an inner concave ring 16 is further provided in the first chamber 14, and the inner concave ring 16 is used to reduce the flow rate and flow of the gas entering the first chamber 14. Preferably, the inner concave ring 16 is axially arranged between the outer air inlet hole 11 and the inner air inlet hole 21. More preferably, the inner concave ring 16 is circumferentially arranged between the outer air inlet hole 11 and the inner air inlet hole 21. For example, Figures 1 to 3 As shown, the concave ring 16 can be a circle of concave rings arranged on the side wall of the outer shell 11, and the width of the corresponding area of ​​the first chamber 14 is narrowed by the circle of concave rings. The concave ring 16 can also be at least one of a circle of convex rings (not shown) on the outer wall of the inner shell 12 and a circle of convex rings (not shown) on the inner wall of the outer shell 11, and the width of the corresponding area of ​​the first chamber is narrowed by the convex ring. As a result, after the gas enters the first chamber, it is blocked by the concave ring and / or the convex ring and the speed and pressure are reduced. It is ensured that the gas enters the second chamber 24 from the inner air inlet at a relatively stable speed and pressure, so that the measurement chip 5 can measure stable gas and improve the measurement accuracy. In addition, since the concave ring can reduce the width of the corresponding area of ​​the first chamber 14. Therefore, compared with the structure without the concave ring, the flow rate of the measurement gas entering the second chamber 24 can also be reduced.

[0045] In addition, the number of the concave ring 16 and the convex ring is not limited to one, and a plurality of them may be provided along the axial direction of the protective shell.

[0046] like Figure 1 , Figure 2 and Figure 5 As shown, in a preferred embodiment, the inner concave ring 16 is arranged on a side closer to the inner air inlet hole 21 than the outer air inlet hole 11. More preferably, the inner concave ring 16 is arranged close to the inner air inlet hole 21. Taking the inner concave ring 16 as an inner concave ring on the side wall of the outer shell 11 as an example, the lower edge of the inner concave ring and the upper edge of the inner air inlet hole 21 are in the same straight line (that is, the inner concave ring is close to the upper end of the inner air inlet hole 21). Thereby, it is ensured that the gas after deceleration and pressure reduction can enter the second chamber faster without traveling a longer path. For example, the distance W4 between the inner concave ring 16 and the inner air inlet hole 21 can be 1.5mm. At this time, the distance W3 between the outer air inlet hole 11 and the inner concave ring 16 can be 6.8mm. But it is not limited to this, and the above-mentioned distance can also be other sizes.

[0047] In another preferred embodiment, the concave ring 16 reduces the width of the corresponding area of ​​the first chamber 14 by about half, that is, the width of the concave ring 16 is about half of the first chamber 14. For example, the width of the first chamber 14 (that is, the distance W1 between the outer wall of the inner shell 2 and the inner wall of the outer shell 1) can be 1.1 mm, and the width of the corresponding area reduced by the concave ring 16 (that is, the distance W2 between the concave ring 16 and the outer wall of the inner shell 2) is 0.6 mm. In this way, the air intake can be reduced by half. If the width of the concave ring 16 is too large, the width of the corresponding area of ​​the first chamber 14 is too narrow, which will lead to insufficient air intake of the second chamber and affect the measurement accuracy; if the width of the concave ring 16 is too small, the width of the corresponding area of ​​the first chamber 14 is too large, which will lead to insufficient speed and pressure reduction of the gas, and will also affect the measurement accuracy. Therefore, setting the width of the concave ring 16 to about half of the first chamber 14 can reduce the gas flow rate and flow and ensure that the test chip can test enough gas.

[0048] Therefore, through the protective shell of the utility model, the high-flow-rate gas to be measured in the exhaust system passes through the outer shell 1, the first chamber 14, the inner concave ring 16 in the first chamber 14 and the inner shell 2 in sequence, and then enters the inner shell (the second chamber 24), so that the airflow is blocked by the outer shell 1, the inner concave ring 16 and the inner shell 2 and is slowed down and reduced in pressure, and then enters the second 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, ensuring that the sensor works stably in the exhaust system, and extending the service life of the sensor.

[0049] like Figure 1 and Figure 4 As shown, further, the buffer part also includes a buffer sleeve 3 nested in the second chamber 24, the buffer sleeve 3 is sleeved between the inner shell 2 and the measuring chip 5, and the measuring end of the top of the measuring chip 5 extends out of the sleeve top opening 33 at the top of the buffer sleeve 3. Figure 5 As shown, the dimension of the measuring chip 5 extending out of the buffer sleeve 3, that is, the distance W5 between the measuring end and the sleeve top opening 33 of the buffer sleeve 3 is preferably 2 mm, but is not limited thereto. Figure 1 As shown, a guide channel 34 is formed between the inner wall of the inner shell 2 and the outer wall of the buffer sleeve 3, and the inner air inlet 21 is located approximately in the middle of the buffer sleeve 3 in the axial direction, so that the inner air inlet 21 is opposite to the side wall of the buffer sleeve 3. Figure 6 As shown, when the gas enters the second chamber 24 from the first chamber 14, it will first be guided upward by the guide channel 34, and then gathered at the sleeve top opening 33, so that the gas is gathered at the measuring end of the measuring chip 5 extending from the sleeve top opening 33, so that the measuring gas can be detected by the measuring chip 5 after entering the second chamber 24 without traveling a long path, thereby improving the measurement efficiency; and ensuring that the gas detection amount of the measuring chip 5 is sufficient, further improving the measurement accuracy.

[0050] In addition, the buffer sleeve 3 can further reduce the speed and pressure of the measurement gas entering the second chamber 24. Specifically, after entering the second chamber 24, the measurement gas moves in the guide channel 34 and is stopped by the buffer sleeve 3, changing the moving path, thereby reducing the speed and pressure. After reaching the measurement end 51 of the measurement chip 5, a steady-state gas is formed that is easy to detect. This further improves the detection accuracy of the gas sensor.

[0051] Continue to refer to Figure 1 and Figure 4 In a specific embodiment, the buffer sleeve 3 includes a small diameter section 31 and a large diameter section 32 located below the small diameter section 31, the large diameter section 32 is sealed and connected to the bottom end of the inner shell 2 (specifically, the area below the inner air inlet 21), and the above-mentioned guide channel 34 is formed between the small diameter section 31 and the inner shell 2. In addition, the buffer sleeve 3 may not be formed into a small diameter section 31 and a large diameter section 32 and is not connected to the inner shell 2, but may be formed into a sleeve with the same diameter and fixed on the top surface of the second boss of the carrier 4 described later. The utility model does not limit the specific structure and installation method of the buffer sleeve 3.

[0052] Reference Figures 1 to 3 In a specific embodiment, the gas outlet portion includes: a gas outlet hole 12 disposed at the top of the outer shell 1 and connecting the second chamber 24 with the outside of the outer shell 1, and a top opening 22 disposed at the top of the inner shell 2. The gas outlet hole 12 is connected to the second chamber 24 through the top opening 22. The top of the inner shell 2 is sealed with the top of the outer shell 1, and the measured gas can flow out of the second chamber 24 through the top opening 22 and the gas outlet hole 12. Thus, the first chamber 14 is formed into a closed annular space, ensuring that the measured gas can only enter the second chamber 24 from the inner air inlet hole 21.

[0053] Continue to refer to Figure 1 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 measured gas can be blocked by the inner shell 2 and reduce speed and pressure after entering the first 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 relatively long, so that the measured gas can flow from top to bottom in the first chamber 14, so that the measured gas enters the second chamber 24 after traveling a long distance in the first chamber 14, and further reduces the flow rate and pressure of the measured gas when entering the second chamber 24.

[0054] 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 first chamber 14 is further increased, thereby further reducing the flow rate and pressure of the measurement gas when entering the second chamber 24.

[0055] Continue to refer to Figures 1 to 3 In a preferred embodiment, the top of the outer shell 1 is provided with a truncated cone-shaped top boss 15 protruding outward from the second chamber, and the top of the inner shell 2 is provided with a connecting flange 25 connected to the side wall of the top boss 15, and the connecting flange 25 is interference-fitted with the top boss 15 to achieve a sealed connection. That is, the top of the inner shell 2 extends to the hypotenuse of the top boss 15 of the outer shell 1 and is sealedly connected with the hypotenuse to form the top opening 22. Among them, the top boss 15 is a truncated cone protruding from the top of the outer shell 1; the connecting flange 25 is an open truncated cone with upper and lower openings located at the top of the inner shell 2, and the top opening 22 is the small end opening of the open truncated cone, and the air outlet 12 is provided in the middle of the top boss 15.

[0056] Preferably, the top of the outer shell 1 is connected to the top opening 22 in the following manner: during assembly, a downward force is applied to the outer shell 1 to press against the inner shell 2, causing the top of the inner shell 2 to deform to form a connecting flange 25, thereby achieving an interference fit sealing manner.

[0057] Reference Figures 1 to 3 and Figure 5 In a preferred embodiment, the aperture Φ1 of the outer air inlet 11 and the aperture Φ2 of the inner air inlet 21 are larger than the aperture Φ3 of the air outlet 12. While ensuring the air intake, the air outlet can also discharge the measured gas according to the Venturi principle. Specifically, the air outlet is arranged at the top of the housing 1 (the top of the top boss 15). When the gas passes through the slope of the top boss 15 (equivalent to the barrier), the air pressure near the port above the leeward side of the barrier is relatively low. At this time, the air pressure in the chamber will be higher than that near the air outlet, and the gas in the chamber will flow out. More preferably, the aperture Φ1 of the outer air inlet 11 is 1.4 mm, the aperture Φ2 of the inner air inlet 21 is 1.2 mm, and the aperture Φ3 of the air outlet 12 is 0.8 mm. According to the Venturi effect, after calculation, the aperture of the air outlet 12 is set to 0.8 mm to ensure that the measured gas can be discharged and the stability of the air pressure in the chamber can be ensured. Therefore, while ensuring sufficient measurement gas (ensuring the intake volume), the diameter of the gas outlet hole 12 is relatively small.

[0058] 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.

[0059] Reference Figure 1-2 In a specific embodiment, the gas sensor further comprises a carrier 4, the measuring chip 5 is arranged in the carrier 4, and the protective shell is installed on the carrier 4 and covers the measuring chip 5. 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 arranged 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.

[0060] In a specific embodiment, the measuring chip 5 is supported in the through hole of the carrier 4 by a supporting block (not shown), and one end of the measuring chip 5 close to the detection end extends out of the through hole. Alternatively, more supporting blocks may be provided to support the measuring chip 5 .

[0061] Reference Figure 1-4 Another specific embodiment of the utility model further provides a protective shell of a gas sensor, the protective shell is used to be installed on a carrier of the gas sensor to cover a measuring chip 5, the protective shell comprises: an outer shell 1 and an inner shell 2 arranged in the outer shell 1, the inner shell 2 is sealed and connected to the outer shell 1 at least in a part of the area, the inner shell 2 is used to cover the measuring chip 5, a first chamber 14 is formed between the inner wall of the outer shell 1 and the outer wall of the inner shell 2; a second chamber 24 is formed in the inner shell 2, and the side wall of the outer shell 1 is provided with an external air inlet 11 connecting the outside of the outer shell 1 and the first chamber, so that the measuring gas can pass through the outer The air inlet 11 enters the first chamber 14; the side wall of the inner shell 2 is provided with an inner air inlet 21 connecting the first chamber 14 and the second chamber 24, and the measuring gas can enter the second chamber 24 from the first chamber 14 through the inner air inlet 21, and the outer air inlet 11 and the inner air inlet 21 are staggered along the axial direction of the protective shell, and the protective shell is also provided with an air outlet portion for guiding the measuring gas to flow out of the protective shell, wherein a buffer portion is also provided in the protective shell, and the buffer portion is used to hinder the flow of the measuring gas entering the first chamber 14 and / or the second chamber 24 to reduce its flow rate and / or flow rate.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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: The protective shell comprises: an outer shell and an inner shell arranged radially inwardly of a side wall of the outer shell, wherein the inner shell is sealedly connected to the outer shell at least in a partial area, and the inner shell is used to cover the measuring chip. A first chamber is formed between the inner wall of the outer shell and the outer wall of the inner shell; a second chamber for accommodating the measuring chip is formed in the inner shell. The side wall of the outer shell is provided with an external air inlet hole connecting the outside of the outer shell and the first chamber, and the measurement gas can enter the first chamber through the external air inlet hole; the side wall of the inner shell is provided with an internal air inlet hole connecting the first chamber and the second chamber, and the measurement gas can enter the second chamber from the first chamber through the internal air inlet hole. The protective shell is also provided with a gas outlet for guiding the measured gas to flow out of the protective shell, wherein A buffer portion is also provided in the protective shell to hinder the flow of the measurement gas into the first chamber and / or the second chamber.

2. The protective shell of the gas sensor according to claim 1, characterized in that: The buffer portion is at least one concave ring formed by partially recessing the side wall of the outer shell radially inward, and / or the buffer portion is at least one convex ring provided on the outer wall of the inner shell and / or the inner wall of the outer shell.

3. The protective shell of the gas sensor according to claim 2, characterized in that: The inner concave ring and / or the convex ring are closer to the inner air inlet hole than to the outer air inlet hole.

4. The protective shell of the gas sensor according to claim 3, characterized in that: The inner concave ring and / or the convex ring are tightly attached to the upper end of the inner air inlet hole in the axial direction.

5. The protective shell of the gas sensor according to any one of claims 1 to 4, characterized in that: The buffer portion has a width approximately half of a width of the first chamber.

6. The protective shell of the gas sensor according to any one of claims 1 to 4, characterized in that: The buffer portion further includes a buffer sleeve, which is disposed in the second chamber between the inner shell and the measurement chip to change a moving path of the measurement gas entering the second chamber to guide the measurement gas to a measurement end of the measurement chip.

7. The protective shell of the gas sensor according to claim 6, characterized in that: The buffer sleeve includes a small diameter section and a large diameter section located below the small diameter section. The outer wall of the large diameter section is sealedly connected to the inner wall of the bottom of the inner shell. A guide channel is formed between the outer wall of the small diameter section and the inner wall of the inner shell. The measuring end of the measuring chip extends out of the top opening of the buffer sleeve.

8. The protective shell of the gas sensor according to any one of claims 1 to 4, characterized in that: The air outlet portion includes: an air outlet hole provided at the top of the outer shell and connecting the second chamber with the outside of the outer shell, and a top opening provided at the top of the inner shell. The top of the inner shell extends longitudinally upward to the top of the outer shell and is sealed and connected with the top of the outer shell to form the top opening.

9. The protective shell of the gas sensor according to claim 8, characterized in that: The top of the outer shell is formed as a truncated cone-shaped top boss protruding outward from the second chamber, and the top of the inner shell extends to the hypotenuse of the top boss and is sealed and connected with the hypotenuse to form the top opening.

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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