Sensing device

Abstract

The invention provides a sensing device which comprises a detection assembly and a shell, the detection assembly comprises a first thermistor, a first conductive part and a first base, the first conductive part is connected with the first base, and the first thermistor is electrically connected with the first conductive part; the shell comprises a first shell body, the first shell body is provided with a first inner cavity and a first through hole, the first inner cavity is an open cavity, and the first thermistor is located in the first inner cavity; the first shell comprises a first top wall, and the first through hole is formed in the first top wall; in the height direction of the sensing device, the first top wall and the first base are located on the two sides of the first inner cavity respectively, the distance between the first top wall and the first base is h1, the distance between the first thermistor and the first top wall is a1, when a1 / h1 ranges from 0.3 to 0.7, air in the first inner cavity can play a good role in heat insulation, and meanwhile, the distance between the first thermistor and the first top wall is larger than the distance between the first thermistor and the first top wall. And the first thermistor can sensitively sense that the detection gas enters the sensing device, so that the detection precision of the sensing device is improved.

Description

Technical Field

[0001] The present application relates to the field of measurement technology, and in particular to a sensor device. Background Art

[0002] The sensing device includes a first thermistor, a first housing and a first inner cavity, wherein the first thermistor is located in the first inner cavity, and the first inner cavity is connected to the external gas. How to enable the first thermistor to achieve high-precision gas detection with little influence from the external temperature is an important research topic in this field. Summary of the invention

[0003] The inventors have found that the above technical problem can be well solved by adjusting the position of the first thermistor in the first inner cavity. To this end, the present application provides a high-precision sensing device.

[0004] The sensor device provided in the present application includes a detection component and a housing, wherein the detection component includes a first thermistor, a first conductive part and a first base, wherein the first conductive part is connected to the first base, and the first thermistor is electrically connected to the first conductive part;

[0005] The housing comprises a first shell, the first shell has a first inner cavity and a first through hole, the first through hole is in communication with the first inner cavity, the first through hole is in communication with the outside of the sensor device, and the first thermistor is located in the first inner cavity;

[0006] The first shell includes a first top wall, and the first through hole is arranged on the first top wall; along the height direction of the sensing device, the first top wall and the first base are respectively located on both sides of the first inner cavity, the distance between the first top wall and the first base is h1, and the distance between the first thermistor and the first top wall is a1, wherein the range of a1 / h1 is 0.3 to 0.7.

[0007] In the sensing device of the present application, the distance between the first top wall and the first base is h1, and the distance between the center of the first thermistor and the first top wall is a1. When the range of a1 / h1 is 0.3 to 0.7, the air in the first inner cavity can play a good heat-insulating role, so that the first thermistor is not affected by the external temperature. At the same time, the first thermistor can also sensitively sense the detection gas entering the sensing device, thereby improving the detection accuracy of the sensing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A schematic diagram of a sensing device provided in one embodiment of the present application;

[0009] Figure 2 A cross-sectional schematic diagram of a sensor device provided in one embodiment of the present application;

[0010] Figure 3 A cross-sectional schematic diagram of a sensor device provided in one embodiment of the present application;

[0011] Figure 4 An explosion diagram of a sensor device provided in one embodiment of the present application;

[0012] Figure 5 A cross-sectional schematic diagram of a sensor device provided in one embodiment of the present application;

[0013] Figure 6 An exploded schematic diagram of a partial structure of a sensor device provided in one embodiment of the present application;

[0014] Figure 7 A cross-sectional schematic diagram of a sensor device provided in one embodiment of the present application;

[0015] Figure 8 A schematic diagram of a sensing device provided in another embodiment of the present application;

[0016] Fig. 9 for Figure 8 A cross-sectional schematic diagram of a sensing device is provided. DETAILED DESCRIPTION

[0017] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0018] It should be clear that the described embodiments are only 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 ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0019] At present, the relevant sensor device includes a detection component 2 and a shell 3, wherein the detection component 2 includes a first thermistor 21a, the shell 3 includes a first shell 31, the first shell 31 has a first inner cavity 311 and a first through hole 312, the first through hole 312 is connected to the first inner cavity 311, the first through hole 312 is connected to the outside of the sensor device 1, the first thermistor 21a is located in the first inner cavity 311, when the gas to be detected enters the first inner cavity 311 through the first through hole 312, the first thermistor 21a senses the change in gas temperature and its resistance value will change accordingly, the change in resistance value will be accompanied by the change in electrical signals, the processing unit of the sensor device will process the electrical signals, so that the sensor device and the air conditioning system will take corresponding countermeasures, such as issuing an alarm prompt, to ensure the safety of the air conditioning system. However, the first thermistor 21a will be affected by the external temperature, resulting in poor detection accuracy.

[0020] In order to improve the detection accuracy of the sensor device 1, Figure 1 As shown, the detection component 2 of the sensor device 1 of the present application includes a first conductive part 22a and a first base 23a, the first conductive part 22a is connected to the first base 23a, and the first thermistor 21a is electrically connected to the first conductive part 22a; the first shell 31 includes a first top wall 313, and the first through hole 312 is arranged on the first top wall 313; the sensor device 1 has a height direction H, along the height direction H of the sensor device 1, the first top wall 313 and the first base 23a are respectively located on both sides of the first inner cavity 311, the distance between the first top wall 313 and the first base 23a is h1, and the distance between the first thermistor 21a and the first top wall 313 is a1, wherein the range of a1 / h1 is 0.3 to 0.7, and further, the range of a1 / h1 is 0.35 to 0.82. By controlling the distance between the first thermistor 21a and the first top wall 313, the first thermistor 21a can be in contact with the gas to be measured as early as possible. At the same time, the distance between the first thermistor 21a and the first top wall 313 can also effectively reduce the influence of the external temperature on the first thermistor 21. The air in the first inner cavity 311 can also fully play a heat-insulating role, avoiding the false alarm phenomenon caused by the influence of the external temperature.

[0021] Furthermore, the first top wall 313 includes an outer wall surface 3131 and an inner wall surface 3132, and the inner wall surface 3132 is closer to the first base 23a relative to the outer wall surface 3131; the first base 23a includes an upper surface 23a3 and a lower surface 23a4, and the upper surface 23a3 is closer to the first top wall 313 relative to the lower surface 23a4; the distance between the first top wall 313 and the first base 23a is the distance between the inner wall surface 3132 and the upper surface 23a3.

[0022] In order to further improve the detection accuracy of the sensor device 1, in one embodiment, Figure 5 As shown, the first top wall 313 includes a first edge A and a second edge B, the maximum distance between the first edge A and the second edge B is d1, perpendicular to the height direction H of the sensor device 1, the distance between the first thermistor 21a and the first conductive portion 22a is b1, wherein b1 / (d1 / 2) ranges from 0.2 to 0.7, and further, b1 / (d1 / 2) ranges from 0.26 to 0.63. When the sensor device 1 is working, the first conductive portion 22a will dissipate heat, and controlling the distance between the first thermistor 21a and the first conductive portion 22a can effectively prevent the first thermistor 21a from being affected by the heat dissipation of the first conductive portion 22a, thereby improving the detection accuracy of the sensor device 1. For example Figure 2 As shown, the first shell 31 is substantially cylindrical, the first top wall 313 is circular, and the maximum distance d1 between the first edge A and the second edge B is the diameter of the first top wall 313 .

[0023] Further, in one embodiment, if Figure 2 As shown, the first thermistor 21a has a center, which is the centroid of the first thermistor 21a; that is, the distance between the first thermistor 21a and the first top wall 313 is the distance between the center of the first thermistor 21a and the first top wall 313; the distance between the first thermistor 21a and the first conductive portion 22a is the distance between the center of the first thermistor 21a and the first conductive portion 22a. The distance between the first thermistor 21a and the first top wall 313 or the distance between the first thermistor 21a and the first conductive portion 22a is further limited, and a more accurate distance can better improve the detection accuracy of the sensor device 1.

[0024] In order to further enable the first thermistor 21a to sense the gas change more quickly and make a rapid detection, in one embodiment, as Figure 2 As shown, at least a portion of the first thermistor 21a is disposed in alignment with the first through hole 312. For ease of arrangement, the first through hole 312 is preferably in the shape of a regular polygon or a circle.

[0025] Along the height direction H of the sensor device 1, the first conductive portion 22a has an end 221, and the end 221 is close to the first top wall 313 relative to the first base 23a. In the related art, the first thermistor 21a of the sensor device 1 is close to the first top wall 313 relative to the end 221. When the sensor device 1 is manufactured, the first housing 31 is easy to hit the first thermistor 21a, thereby affecting the detection accuracy. Therefore, in order to improve the detection accuracy of the sensor device 1, in one embodiment, as shown in FIG. Figure 3 and Figure 4 As shown, along the height direction H of the sensor device 1 , the first thermistor 21 a is not higher than the end 221 of the first conductive portion 22 a .

[0026] The detection component 2 includes a first lead 24a, the first thermistor 21a is electrically connected to the first lead 24a, and the first lead 24a is electrically connected to the first conductive portion 22a. Figure 4 and Figure 6 As shown, the first lead 24a is not higher than the end 221 of the first conductive portion 22a, which can reduce the deformation of the first lead 24a under the action of external force. In addition, the overall height of the detection component 2 can be reduced, which is conducive to the miniaturization of the detection component 2. Further, along the height direction H, the first lead 24a is located on the same side of the end 221.

[0027] In one embodiment, if Figure 3 As shown, in order to further reduce the deformation of the first lead 24 a under the action of external force, the first lead 24 a is fixedly connected to the end 221 .

[0028] In order to enhance the connection firmness between the first lead 24a and the first conductive portion 22a, the first lead 24a is provided with a first connecting portion 24a1, and the first connecting portion 24a1 is at least partially electrically connected to the first conductive portion 22a, and the first connecting portion 24a1 is linear or planar. When the first connecting portion 24a1 is linear, the connection between the first lead 24a and the first conductive portion 22a is a linear connection, and when the first connecting portion 24a1 is planar, the connection between the first lead 24a and the first conductive portion 22a is a planar connection. In one embodiment, as Figure 6 As shown, surface connection is preferred.

[0029] In some embodiments, the material of the first connection portion 24a1 is tin or a tin alloy. The thermal conductivity of tin is 67W / m·K, the melting point is 232°C, and the resistivity at 25°C is 0.126μΩ·m. Although the resistivity of tin is greater than that of precious metals such as gold, silver, and copper, the thermal conductivity of tin is much smaller than that of precious metals such as gold, silver, and copper. When tin or a tin alloy is used as the first connection portion 24a1, the negative impact of its larger resistivity on the detection accuracy compared to precious metals such as gold, silver, and copper can be completely offset by the positive impact of the small thermal conductivity on the detection accuracy, thereby improving the detection sensitivity and detection accuracy of the thermal conductivity sensor device 1. That is to say, the resistivity of tin or tin alloy is greater than that of precious metals such as gold, silver, and copper, which may reduce the detection accuracy of the sensor device 1; however, the thermal conductivity of tin or tin alloy is smaller than that of precious metals such as gold, silver, and copper, which can improve the detection accuracy of the sensor device 1. For the thermal conductivity sensor device 1, the improvement of detection accuracy due to the small thermal conductivity of tin or tin alloy is greater than the reduction of detection accuracy due to its large resistivity. Therefore, in general, using tin or tin alloy as the main component of the first connecting portion 24a1 can improve the detection accuracy of the sensor device 1.

[0030] In addition, since tin and tin alloys have a low melting point, they can be electrically connected to the lead-out portion with low-energy welding, reducing damage to the detection portion during the welding process. Moreover, compared with precious metals, tin or tin alloys as the connection portion can also reduce the manufacturing cost of the sensor device 1.

[0031] In some embodiments, the tin alloy is a tin-lead alloy, a tin-bismuth alloy, a tin-bismuth-silver alloy, a tin-cadmium alloy, or a tin-indium alloy. 92.5 Sn5Ag 2.5 SnBi 58 SnBi 35Ag1. Different tin alloys have their own thermal conductivity, melting point and resistivity. Different tin alloys can be selected according to the detection needs, on the premise of meeting the above-mentioned thermal conductivity and melting point requirements. For example, a metal with low thermal conductivity, low resistivity and low melting point can be selected to form an alloy with tin, so that the thermal conductivity of the alloy is within the range specified in this application, and at least one of the resistivity and melting point is also within the range specified in this application.

[0032] In order to improve the sensitivity of the sensor device 1 in transmitting electrical signals, in some embodiments, Figure 6 As shown, the first lead 24a includes at least one pair of electrodes 241, 242, and the electrodes 241, 242 are electrically connected to the first thermistor 21a; at least one pair of electrodes 241, 242 are axially symmetrically arranged, or at least one pair of electrodes 241, 242 are centrally symmetrically arranged.

[0033] In order to improve the detection accuracy of the sensor device 1, in one embodiment, Figure 7 As shown, the housing 3 includes a second housing 32, the second housing 32 has a second inner cavity 322, and the second inner cavity 322 is a closed cavity; the detection component 2 includes a second thermistor 21b, the second thermistor 21b is located in the second inner cavity 322, and the second thermistor 21b is used as a reference resistor in the second inner cavity 322. When the first thermistor 21a and the second thermistor 21b reach a certain resistance difference, the sensor device 1 will sound an alarm. Further, in one embodiment, the first thermistor 21a and the second thermistor 21b are both NTC thermistor chips, so as to facilitate component selection.

[0034] The detection component 2 includes a second conductive portion 22b, a second lead 24b and a second connecting portion 24b1, the second conductive portion 22b is electrically connected to the second lead 24b, and the second lead 24b is electrically connected to the second thermistor 21b. In order to further facilitate the selection of components, in some embodiments, the selection and connection method of the second lead 24b and the second connecting portion 24b1 are the same as those of the first lead 24a and the second connecting portion 24a1.

[0035] In order to prevent the ambient air temperature from affecting the second thermistor 21b and thus affecting the detection accuracy of the sensor device 1, in one embodiment, Figure 8 As shown, there is a gap between the first shell 31 and the second shell 32. Alternatively, in one embodiment, as shown in FIG. Figure 8As shown, the first shell 31 and the second shell 32 are an integral piece, the outer shell 3 includes a connecting wall 30, the first shell 31 and the second shell 32 are both connected to the connecting wall 30, and further, a spacing groove 33 is provided between the first shell 21 and the second shell 32; along the height direction H, the connecting wall 30 is away from the first top wall 313 relative to the spacing groove 33, and the size of the spacing groove 33 in the height direction H is larger than the size of the connecting wall 30 in the height direction H, so that the spacing groove 33 isolates the heat conduction between the shared spacing wall of the first shell 31 and the second shell 32, thereby further improving the detection accuracy of the sensor device 1.

[0036] In one embodiment, if Fig. 9 As shown, the size of the spacing groove 33 in the height direction H of the sensor device 1 is L1, and the size of the connecting wall 30 in the height direction H of the sensor device 1 is L2, where L1 and L2 satisfy the following relationship: 2≤L1 / L2≤4. When the size of the spacing groove 33 in the height direction H is more than twice and less than four times the size of the connecting wall 30 in the height direction H, the heat transfer between the first inner cavity 311 and the second inner cavity 322 is further reduced, thereby further improving the detection accuracy of the sensor device 1, while taking into account the connection strength of the spacing groove 33. Preferably, L1 / L2=3, which can reduce the heat transfer between the first inner cavity 311 and the second inner cavity 322, and the connection strength between the first shell 31 and the second shell 32 is strong enough.

[0037] In one embodiment, if Figure 4 As shown, the first shell 31 includes a first flange portion 314, and the first flange portion 314 is close to the first base 23a relative to the first through hole 312. The second shell 32 includes a second top wall 321 and a second flange portion 323. The detection component 2 includes a second base 23b. Along the height direction H of the sensor device 1, the second top wall 321 and the second base 23b are respectively located on both sides of the second inner cavity 322; along the height direction H, the second flange portion 323 is close to the second base 23b relative to the second top wall 321.

[0038] The first base 23a includes a first step 23a1, which is protruded from the first base 23a toward the first top wall 313, and the second base 23b includes a second step 23b1, which is protruded from the second base 23b toward the second top wall 321. The first base 23a is provided with a first end face 23a2, which is away from the first top wall 313 relative to the first step 23a1, and the first end face 23a2 is connected to the first step 23a1; the second base 23b is provided with a second end face 23b2, which is away from the second top wall 321 relative to the second step 23b1, and the second end face 23b2 is connected to the second step 23b1. In order to better seal the installation, the first flange portion 314 is sealed and connected to the first end face 23a2, and the second flange portion 323 is sealed and connected to the second end face 23b2, wherein the sealing connection method includes welding or sealing adhesive connection or connection through a sealing ring.

[0039] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A sensor device, comprising a detection component and a housing, characterized in that: The detection assembly includes a first thermistor, a first conductive portion and a first base, the first conductive portion is connected to the first base, and the first thermistor is electrically connected to the first conductive portion; The housing comprises a first shell, the first shell has a first inner cavity and a first through hole, the first through hole is in communication with the first inner cavity, the first through hole is in communication with the outside of the sensor device, and the first thermistor is located in the first inner cavity; The first shell includes a first top wall, and the first through hole is arranged on the first top wall; along the height direction of the sensing device, the first top wall and the first base are respectively located on both sides of the first inner cavity, the distance between the first top wall and the first base is h1, and the distance between the first thermistor and the first top wall is a1, wherein the range of a1 / h1 is 0.3 to 0.

7.

2. The sensor device according to claim 1, characterized in that: The first top wall comprises a first edge and a second edge, the maximum distance between the first edge and the second edge is d1, perpendicular to the height direction of the sensor device, the distance between the first thermistor and the first conductive part (22a) is b1, wherein b1 / (d1 / 2) ranges from 0.2 to 0.

7.

3. The sensor device according to claim 2, characterized in that: The first thermistor has a center, the center being the centroid of the first thermistor; The distance between the first thermistor and the first top wall is the distance between the center of the first thermistor and the first top wall; The distance between the first thermistor and the first conductive portion is the distance between the center of the first thermistor and the first conductive portion.

4. The sensor device according to claim 1, characterized in that: The first top wall includes an outer wall surface and an inner wall surface, and the inner wall surface is closer to the first base relative to the outer wall surface; The first base comprises an upper surface and a lower surface, wherein the upper surface is closer to the first top wall than the lower surface; The distance between the first top wall and the first base is the distance between the inner wall surface and the upper surface.

5. The sensor device according to claim 1, characterized in that: Along the height direction of the sensor device, the first conductive portion has an end, the end is close to the first top wall relative to the first base, and the first thermistor is not higher than the end of the first conductive portion.

6. The sensor device according to claim 1, characterized in that: The detection component includes a first lead, the first thermistor is electrically connected to the first lead, the first lead is provided with a first connecting portion, the first connecting portion is at least partially electrically connected to the first conductive portion, the first connecting portion is linear or planar, and the material of the first connecting portion includes tin or tin alloy; along the height direction, the first lead is located on the same side of the end.

7. The sensor device according to claim 6, characterized in that: The first lead includes at least one pair of electrodes, and the electrodes are electrically connected to the first thermistor; The at least one pair of electrodes is arranged axially symmetrically, or the at least one pair of electrodes is arranged centrally symmetrically.

8. The sensor device according to claim 1, characterized in that: The first through hole is at least partially aligned with the first thermistor.

9. The sensor device according to claim 1, characterized in that: The first thermistor is an NTC thermistor.

10. The sensor device according to claim 1, characterized in that: The housing includes a second shell, the second shell has a second inner cavity, and the second inner cavity is a closed cavity; the detection component includes a second thermistor, and the second thermistor is located in the second inner cavity; There is a distance between the first shell and the second shell; or, the first shell and the second shell are an integral piece, the outer shell comprises a connecting wall, and the first shell and the second shell are both connected to the connecting wall.

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