Sensor unit and its mounting structure

Abstract

The sensor unit (10) of the present invention comprises: a housing (20) capable of measuring the temperature of a fluid flowing in a tube (51), having an internal space (41) and a cylindrical portion (30) connecting the internal space (41) with the tube (51); and a substrate (33) having a temperature sensor (34) mounted on a first surface (33a), the substrate (33) being arranged in the internal space (41) of the housing (20), and an external opening (31) on the external side of the cylindrical portion (30) being connectable to the temperature sensor (34). In the tube (51), the inner side opening (32) of the inner space side of the cylindrical portion (30) is blocked by the first surface (33a) of the substrate, and the temperature sensor (34) is arranged inside the cylindrical portion (30). The inside of the cylindrical portion (30) has a protective portion (65) filled with a resin material (35) covering the temperature sensor (34). Therefore, the temperature detection portion is set to a simple structure, which can reduce the manufacturing cost compared with the past, improve the transportation efficiency, and is not easily damaged by falling or collision.

Description

Technical Field

[0001] The present invention relates to a sensor unit having a temperature detection element, and more particularly to a sensor unit for detecting the intake air temperature in an intake passage of an engine of a vehicle and a mounting structure thereof. Background Art

[0002] In the engine throttle valve device described in Patent Document 1, a tube (hollow cylinder) is integrally formed on a housing of a throttle valve having an intake passage opened and closed by the throttle valve and passing through the side wall of the throttle valve, and its closed front end faces the intake passage. The intake air temperature sensor is accommodated in close contact with the sensor element on the inner surface of the front end of the tube. After the intake air temperature sensor is accommodated, synthetic resin is poured into the hollow part of the tube.

[0003] However, since the synthetic resin flows from the opening side of the hollow cylinder to the bottomed front end side, the air in the hollow cylinder is sent to the front end side. Therefore, bubbles are easily generated around the sensor element, and the filling based on the synthetic resin may become uneven. Therefore, the responsiveness of the measurement of the intake temperature becomes low, and there is a problem that the measurement performance is easily biased due to the difference in the filling state of each product.

[0004] Therefore, Patent Document 2 describes a sensor unit that suppresses air in a hollow cylindrical body from remaining at the front end when the resin material is filled. The sensor unit described in the document includes a housing, a hollow cylindrical body extending from the housing, and a temperature detection element arranged inside the front end of the cylindrical body in the extending direction. The cylindrical body has a hole that penetrates the wall of the front end, and the inside of the cylindrical body is filled with resin material. According to this structure, the responsiveness of temperature measurement can be ensured and the deviation of measurement performance can be suppressed.

[0005] However, the temperature detection portion of the sensor unit of patent document 2 is configured with a thermistor at the inner front end of the cylindrical body that protrudes slenderly from the shell. Therefore, the thermistor is electrically connected to the substrate configured in the shell through the stretched wiring. In this structure, it is difficult to connect the wire to the substrate, which becomes the main reason for the increase in manufacturing cost. In addition, since the temperature detection portion protrudes from the shell, there is a problem that the package shape is damaged and the transportation efficiency is reduced, and the slender protruding cylindrical body is easily damaged due to falling or collision during assembly. Moreover, since the thermistor measures the temperature via the shell and the resin material, there is a problem that it takes a little time to respond to temperature changes.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2004-124874

[0009] Patent Document 2: Japanese Patent Application Publication No. 2019-020251 Summary of the invention

[0010] Technical problem to be solved by the invention

[0011] Therefore, an object of the present invention is to provide a sensor unit having a simple structure for a temperature detection portion, which can reduce manufacturing costs compared with the related art, has high conveyance efficiency, and is less likely to be damaged by impact due to falling or collision.

[0012] Means for solving technical problems

[0013] The present invention provides a sensor unit capable of measuring the temperature of a fluid flowing in a tube. The sensor unit is characterized in that it comprises: a shell having an internal space and a cylindrical portion connecting the internal space with the outside; and a substrate having a temperature sensor mounted on a first surface, the substrate being arranged in the internal space of the shell, an external opening on the external side of the cylindrical portion being capable of being connected to the tube, an internal opening on the internal space side of the cylindrical portion being blocked by the first surface of the substrate, the temperature sensor being arranged inside the cylindrical portion, and a protective portion filled with a resin material covering the temperature sensor being provided inside the cylindrical portion.

[0014] By mounting the temperature sensor on the first surface of the substrate, there is no need to make a detour for the wiring that electrically connects the temperature sensor to the substrate, so the positioning and assembly of the temperature sensor becomes easy. Therefore, the manufacturing cost of the sensor unit can be suppressed. In addition, since less resin material can be used to seal the temperature sensor, the time required for the resin material to solidify can be shortened, and the sensor unit can be made lightweight. Due to the lightweight, the force applied during a collision becomes smaller, making the sensor unit impact-resistant and not easily damaged. Moreover, since there is no need to set the cylindrical portion to a shape that protrudes slenderly from the shell, bubbles are not easily generated when the resin material is filled and sealed. As a result, the accuracy and responsiveness of the temperature measurement based on the sensor unit become good.

[0015] Alternatively, the shell may include: a discharge port opening at a position different from the external opening of the cylindrical portion and connected to the tube; and a connecting passage connecting the discharge port with the cylindrical portion, wherein the cylindrical portion includes: the protective portion filled with the resin material and in contact with the substrate, and a space portion located between the external opening connected to the tube and the protective portion and not filled with the resin material, and the connecting passage is connected to the space portion.

[0016] Preferably, the external opening and the discharge port can be connected to the tube, and when the external opening and the discharge port are connected to the tube, the external opening communicates with the fluid flowing in the tube upstream of the discharge port.

[0017] According to the above structure, a part of the fluid flowing in the tube is taken into the space portion from the outer opening of the cylindrical portion, forming a flow of the fluid to the discharge port via the connecting passage. In addition, when the outer opening and the discharge port are connected to the tube, the outer opening is connected to the upstream of the flow of the fluid in the tube compared to the discharge port, so that the fluid flows smoothly. Therefore, the accuracy and responsiveness of the temperature sensor in the cylindrical portion of the sensor unit to measure the temperature of the fluid in the tube are improved.

[0018] Alternatively, the housing may have a recessed portion extending away from the cylindrical portion on a portion of its outer surface, and when the housing is mounted on the tube, the discharge port is formed by a portion of the recessed portion. The discharge port may also be provided at an end portion of the recessed portion on the opposite side of the cylindrical portion.

[0019] When the housing is mounted on the tube, the connection passage can be easily formed by covering the recessed portion on the outer surface of the tube. In addition, by arranging the discharge port at the end on the opposite side of the cylindrical portion, the connection passage can be lengthened, so that the flow of the fluid in the sensor unit becomes smooth.

[0020] Preferably, a first anti-etching portion formed along the outer peripheral shape of the inner side opening of the cylindrical portion and a second anti-etching portion formed along the inner peripheral shape of the cylindrical portion are provided on the first surface of the substrate, and an end portion of the inner side opening of the cylindrical portion is arranged between the first anti-etching portion and the second anti-etching portion.

[0021] This structure forms a labyrinth structure in which the first anti-etching part and the second anti-etching part sandwich the end portion of the inner opening. Therefore, when the temperature sensor inside the cylindrical part is covered and sealed with a resin material, the resin material can be prevented from passing through the gap between the substrate and the end portion of the cylindrical part and flowing from the inside of the cylindrical part into the internal space of the housing.

[0022] A groove portion may be provided at the end portion of the inner opening, and a third resist portion may be provided at a position facing the groove portion between the first resist portion and the second resist portion on the first surface of the substrate.

[0023] By fitting the groove portion and the third positioning portion, a complex labyrinth structure can be formed, thereby more effectively preventing the sealing material from flowing into the internal space of the housing.

[0024] Preferably, the resin material has a thermal conductivity of 0.3 (W / m·K) or more in the extension direction of the cylindrical portion.

[0025] By using a resin material having a high thermal conductivity in the elongation direction of the cylindrical portion, the temperature of the fluid is easily transmitted to the temperature sensor via the resin material even when the thickness of the resin material protecting the temperature sensor is increased. Therefore, the temperature of the fluid can be measured with good responsiveness while using a resin material having a thickness sufficient to protect against corrosive gases and suppressing a decrease in the sensitivity of the temperature sensor.

[0026] The present invention provides an installation structure of a sensor unit, comprising: a tube for fluid flow; and the sensor unit of the present invention installed on the tube and capable of measuring the temperature of the fluid, the tube having: a valve capable of adjusting the flow rate of the fluid; a first opening portion, sandwiching the valve and located on the upstream side of the flow of the fluid; and a second opening portion, sandwiching the valve and located on the downstream side of the flow of the fluid, the first opening portion being connected to the external opening, and the second opening portion being connected to the discharge port.

[0027] The pressure in the tube is high on the upstream side of the valve and low on the downstream side. Therefore, by providing the first opening and the second opening in a manner that the valve is sandwiched between the first opening and the second opening, the first opening is connected to the external opening, and the second opening is connected to the discharge port, thereby forming a flow of fluid in the sensor unit. As a result, the fluid in the tube as the measurement object can be efficiently taken into the space portion of the cylindrical portion. Therefore, the accuracy and responsiveness in the temperature measurement of the fluid in the tube are improved.

[0028] The present invention provides an installation structure of a sensor unit, comprising: a tube for fluid flow; and the sensor unit of the present invention, which is installed on the tube and can measure the temperature of the fluid and has a shell with a recessed portion, wherein the tube has: a valve that can adjust the flow rate of the fluid; a first opening that is located on the upstream side of the flow of the measured fluid with the valve sandwiched therebetween; and a second opening that is located on the downstream side of the flow of the measured fluid with the valve sandwiched therebetween, wherein the sensor unit is configured in a state in which the recessed portion is covered by the tube, the first opening is connected to the external opening, and the second opening faces the recessed portion.

[0029] The second opening may be provided at a portion of the tube corresponding to an end of the recessed portion on a side away from the cylindrical portion, and the discharge port may be provided at an end of the recessed portion on an opposite side to the cylindrical portion.

[0030] By using a tube to cover the recessed portion of the housing of the sensor unit of the present invention to form a communication path, it is not necessary to form a tubular structure for forming the communication path with the housing alone. Therefore, the manufacturing of the housing constituting the sensor unit becomes easy. In addition, by providing the discharge port at the end on the opposite side of the cylindrical portion, the connection path can be lengthened to make the flow of the fluid smooth.

[0031] Effects of the Invention

[0032] According to the present invention, a sensor unit can be provided which can simplify the process compared with the related art, thereby reducing the manufacturing cost, has high conveying efficiency, is resistant to drops and collisions during assembly and movement, and has excellent handling properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a side view showing the structure of the sensor unit according to the first embodiment.

[0034] Figure 2 It is a plan view showing the structure of the sensor unit according to the first embodiment.

[0035] Figure 3 This is a cross-sectional view schematically showing a state in which the sensor unit according to the first embodiment is attached to a pipe in which a fluid flows, which is an object of temperature measurement.

[0036] Figure 4 This is a cross-sectional view of the cylindrical body in Embodiment 1.

[0037] Figure 5 Yes Figure 4 A cross-sectional view showing an enlarged view of a circled portion B in the cylindrical body.

[0038] Figure 6 It is a perspective view schematically showing a state in which the cylindrical body and the substrate including the first resist portion and the second resist portion in the first embodiment are decomposed.

[0039] Figure 7 Yes means Figure 5 A cross-sectional view of a modified example of the maze structure shown.

[0040] Figure 8 Yes means Figure 4 A cross-sectional view of another variation of the labyrinth structure shown.

[0041] Fig. 9 It is a cross-sectional view schematically showing a state where the sensor unit according to Embodiment 2 is attached to a pipe.

[0042] Fig.10 This is a cross-sectional view schematically showing a state in which a modification of the sensor unit according to the second embodiment is attached to a pipe.

[0043] Fig.11 It is a side view showing the structure of a conventional sensor unit.

[0044] Fig.12 It is a cross-sectional view schematically showing a state where a conventional sensor unit is attached to a pipe. DETAILED DESCRIPTION

[0045] <Implementation method 1>

[0046] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each of the drawings, the same components are denoted by the same reference numerals, and description thereof will be appropriately omitted.

[0047] Figure 1 is a side view showing the structure of the sensor unit 10 of this embodiment, Figure 2 1 is a top view showing the structure of the sensor unit 10. In each figure, XYZ coordinates are shown as reference coordinates. The Z direction is the extension direction along the cylindrical portion 30, and the XY plane is a plane orthogonal to the Z direction. In the following description, the state observed along the Z direction is sometimes referred to as a top view. Figure 1 Although the description is given with reference to the up and down directions, the posture of the sensor unit 10 is not limited thereto.

[0048] The sensor unit 10 is mounted on a throttle valve (not shown) used in the engine of a motorcycle, automobile, or other vehicle. The throttle valve has an intake passage (pipe) opened and closed by a throttle valve (not shown), and the sensor unit 10 electrically detects the intake air temperature in the intake passage. The sensor unit 10 is implemented in a manner that includes a unit for detecting the opening and closing of the throttle valve and the pressure in the intake passage in addition to the temperature in the intake passage, but the following mainly describes the structure related to temperature measurement.

[0049] like Figure 1 or Figure 2 As shown in FIG. 1 , the sensor unit 10 includes a housing 20 made of synthetic resin. The housing 20 includes a housing body 22, and a main body upper portion 21 constituting the upper portion of the housing body 22 is shaped to extend laterally from the housing body 22. Figure 2 As shown, threaded holes 23a and 23b are provided on the upper surface of the main body upper part 21, and screws are passed through them to engage with the mounting surface of the throttle valve, thereby fixing the housing 20 to the throttle valve. When the sensor unit 10 is fixed to the throttle valve, it is possible to measure the temperature of the fluid in the intake passage (pipe) of the engine.

[0050] Figure 32 is a cross-sectional view schematically showing a state in which the sensor unit 10 of the present embodiment is installed in the air intake passage opened and closed by the valve 50, that is, the tube 51. As shown in the figure, the housing 20 has an internal space 41, and the internal space 41 is connected to the outside through the cylindrical portion 30. The external opening 31 of the cylindrical portion 30 is connected to the first opening 52 formed on the side wall of the tube 51, and the internal opening 32 of the cylindrical portion 30 is blocked by the substrate 33. In addition, in the state in which the internal opening 32 is blocked, a temperature sensor 34 is arranged at the position of the substrate 33 which becomes the inner side of the cylindrical portion 30. The fluid of the tube 51 flows into the interior of the cylindrical portion 30, and the temperature of the inflowing fluid is measured by the temperature sensor 34.

[0051] The housing 20 is provided with a throttle valve sensor 24 for electrically detecting the opening degree of the throttle valve. The throttle valve sensor 24 is connected to a valve stem (not shown) supporting the throttle valve through a connecting hole 25 .

[0052] A circuit board common to the throttle valve sensor 24 and the temperature sensor 34 is installed in the housing 20 . In the circuit on the board, the throttle valve opening is calculated based on the detection result of the throttle valve sensor 24 , and the intake air temperature is calculated based on the detection result of the temperature sensor 34 .

[0053] The housing 20 is provided with a coupler 26 formed in a square tube shape. The coupler 26 is provided with a plurality of terminals 27 electrically connected to the circuit board inside the square tube-shaped portion. The detection signals obtained by the throttle sensor 24, the pressure sensor, and the temperature sensor 34 and the calculation results obtained by the circuits are output to a control unit (not shown) connected to the plurality of terminals 27.

[0054] Fig.11 is a side view showing the structure of a conventional sensor unit 100. Fig.12 1 and 2 are cross-sectional views schematically showing a state where the sensor unit 100 is mounted on the intake passage of the engine, that is, the pipe 51. As shown in these figures, the conventional sensor unit 100 includes a cylindrical body 130 having a thermistor 131 disposed therein, and the cylindrical body 130 protruding elongated from the housing 20 is disposed in the pipe 51 to measure the temperature of the fluid in the pipe 51.

[0055] like Fig.11 , Fig.12As shown, the conventional sensor unit 100 has an elongated cylindrical body 130 inserted into the tube 51 during measurement, and the thermistor 131 inside the thermistor 131 is electrically connected to the substrate 133 via the wire 132. Therefore, when the thermistor 131 is connected to the substrate 133 via the wire 132, it is difficult to position the thermistor 131 at a predetermined position, which is one reason why the manufacturing cost is increased due to the complication of the process. In addition, when the thermistor 131 is arranged at a predetermined position at the front end of the cylindrical body 130, it is easy to involve air when potting with the resin material 134. If the potted resin material 134 contains air, the accuracy and responsiveness of the temperature measurement will be reduced. The potting of the resin material 134 is not only implemented near the thermistor 131, but also implemented at a position in the housing 135 that does not hinder the operation of the throttle valve sensor, etc. Therefore, the curing of the resin material 134 takes a long time, which is the reason why the weight of the sensor unit 100 becomes heavier. Moreover, the cylindrical body 130 protruding from the housing 135 is also a cause of damage and reduced conveying efficiency due to accidental collision during or after manufacturing. In addition, since the resin material 134 and the cylindrical body 130 exist between the thermistor 131 and the fluid in the tube 51, the responsiveness in temperature measurement is insufficient.

[0056] Therefore, the sensor unit 10 of this embodiment uses a temperature sensor mounted (installed) on the substrate instead of a thermistor. Figure 1 or Figure 2 As shown, the cylindrical portion 30 does not protrude from the housing 20, thereby achieving cost reduction due to simplification of the manufacturing process, improvement of the conveying efficiency, reduction of the risk of damage, improvement of the responsiveness, etc.

[0057] Figure 4 is a cross-sectional view of the cylindrical portion 30 in this embodiment. Figure 2 A temperature sensor 34 is mounted on the first surface 33 a of the substrate 33 .

[0058] The sensor unit 10 of this embodiment has a structure in which a temperature sensor chip is directly mounted on a substrate, thereby eliminating the elongated protruding cylindrical body 130 in the conventional sensor unit 100. Therefore, the sensor unit 10 is excellent in manufacturing cost, transportation efficiency, risk of damage, and the like.

[0059] The substrate 33 is disposed in the internal space 41 of the housing 20 (see Figure 3 ). The inner opening 32 on the inner space 41 side of the cylindrical portion 30 is blocked by the first surface 33a of the substrate 33. The temperature sensor 34 is arranged inside the cylindrical portion 30, and the inside of the cylindrical portion 30 is filled with a resin material 35 covering the temperature sensor 34. According to this structure, only the resin material 35 exists between the temperature sensor 34 and the fluid in the tube 51. Figure 4 In the embodiment, a part of the cylindrical portion 30 is used as the protection portion 65 filled with the resin material 35 , but the entire cylindrical portion 30 may be used as the protection portion 65 filled with the resin material 35 .

[0060] The temperature sensor 34 is a so-called chip-type temperature sensor. Unlike conventional thermistors, the chip-type temperature sensor 34 is not mounted on the substrate 33 using a wire, so the sensor unit 10 can be manufactured more easily. Since only the cylindrical portion 30 is sealed, the amount of resin material 35 used can be reduced, and the time required for drying can be shortened. As a result, the manufacturing cost can be reduced compared to the conventional method (see Fig.12 ).

[0061] The cylindrical portion 30 that connects the internal space 41 to the outside Fig.11 and Fig.12 Compared with the cylindrical body 130 in the conventional sensor unit 100 shown in FIG. 1 , the cross-sectional area when cut along a plane parallel to the XY plane is large, and the length in the Z direction is short. Therefore, when the resin material 35 flows into the cylindrical portion 30, the resin material 35 is not easy to be entrained in bubbles. In addition, the outer opening 31 of the cylindrical portion 30 is not covered by the cylindrical portion 30, and the temperature sensor 34 measures the temperature of the fluid only through the resin material 35. Therefore, the manufacturing process becomes simple, and the temperature responsiveness of the sensor unit 10 can be improved.

[0062] The resin material 35 is preferably a resin having resistance to protect the temperature sensor 34 from corrosive gases and having high thermal conductivity. By using a resin having high thermal conductivity as the resin material 35, the speed at which the temperature of the fluid is transmitted to the temperature sensor 34 becomes faster, so the responsiveness of the sensor unit 10 is improved. From the viewpoint of making the responsiveness to temperature changes good, the thermal conductivity of the cylindrical portion 30 in the extension direction (Z direction) is preferably 0.3 (W / m·K) or more, more preferably 1.0 (W / m·K) or more, and further preferably 3.0 (W / m·K) or more. As the resin material 35 having resistance and high thermal conductivity, polyurethane resin, epoxy resin, etc. can be listed.

[0063] Figure 5 Yes Figure 4 The maze structure for holding the resin material 35 in the cylindrical portion 30 is described by enlarging the cross-sectional view of the circled portion B in the cylindrical portion 30. Figure 4 and Figure 5As shown, a first resist portion 36 formed along the outer peripheral shape of the inner opening 32 of the cylindrical portion 30 and a second resist portion 37 formed along the inner peripheral shape of the cylindrical portion 30 are provided on the first surface 33a on the cylindrical portion 30 side of the main surface of the substrate 33. And an end portion 32e of the inner opening 32 in the cylindrical portion 30 is arranged between the first resist portion 36 and the second resist portion 37.

[0064] The end 32e of the cylindrical portion 30 is arranged in contact with the first surface 33a of the substrate 33. However, it is believed that due to the deviation of the processing accuracy of the end 32e and the first surface 33a, the assembly deviation when the cylindrical portion 30 and the substrate 33 are assembled, etc., a small gap is generated between the end 32e and the first surface 33a. In the case where such a gap is generated, the resin material 35 seeps from the gap to the internal space 41, which becomes a cause and may cause a bad situation. According to the above structure, as shown by the thick line in the figure, even if there is a gap between the first anti-etching part 36 and the inner side surface of the cylindrical portion 30, between the end 32e of the cylindrical portion 30 and the first surface 33a of the substrate 33, and between the second anti-etching part 37 and the outer side surface of the cylindrical portion 30, a maze structure with a U-shaped cross section is formed. The labyrinth structure can keep the resin material 35 flowing into the inner side of the cylindrical portion 30 inside the cylindrical portion 30, and prevent the resin material 35 from flowing from between the substrate 33 and the cylindrical portion 30 to the internal space 41 of the housing 20 (see Figure 3 ) flows out.

[0065] The first resist portion 36 is a structure in which a resist film 36b is formed on a Cu pattern 36a formed of copper. By forming the resist film 36b on the Cu pattern 36a formed on the substrate 33, the first resist portion 36 can be easily formed to a height sufficient to prevent the outflow of the resin material 35. In addition, the second resist portion 37 also has a structure in which a resist film 37b is formed on a Cu pattern 37a.

[0066] By using the Cu patterns 36a and 37a formed on the substrate 33, the first resist portion 36 and the second resist portion 37 having a thickness sufficient to form a maze structure can be formed. Since the Cu pattern is formed on the surface of the substrate 33, when the Cu pattern is produced, the Cu patterns 36a and 37a are formed in the regions corresponding to the first resist portion 36 and the second resist portion 37. Moreover, by further forming the resist film 36b and the resist film 37b on the Cu patterns 36a and 37a, for example, the first resist portion 36 and the second resist portion 37 having a height of about 70 μm can be formed.

[0067] Figure 6Schematically showing a cylindrical portion 30 and a substrate 33 having a first anti-etching portion 36 and a second anti-etching portion 37 in an embodiment of the present invention in a decomposed state. As shown in the figure, an annular anti-etching pattern, i.e., a first anti-etching portion 36 and a second anti-etching portion 37, having different diameters, is provided on the first surface 33a of the substrate 33, and an inner side opening 32 of the cylindrical portion 30 is arranged between the first anti-etching portion 36 and the second anti-etching portion 37. Thus, a labyrinth structure can be easily formed on the contact surface between the cylindrical portion 30 and the substrate 33. Therefore, the manufacturing cost can be suppressed and the resin material 35 (potting material) can be easily prevented from leaking from the cylindrical portion 30. In addition, as a method for making the cylindrical portion 30 of the housing 20 close to the substrate 33, a known method such as riveting and screw fixing can be used.

[0068] <Modification>

[0069] Figure 7 Yes means Figure 5 2 is a cross-sectional view of a modified example of the labyrinth structure shown in FIG. As shown in the figure, a groove portion 38 may be formed at the end portion 32e of the cylindrical portion 30 that contacts the substrate 33, and a third resist portion 39 may be additionally provided at a portion of the substrate 33 that is opposite to the groove portion 38. The third resist portion 39 is a structure in which a resist film 39b is formed on a Cu pattern 39a. By embedding the third resist portion 39 in the groove portion 38, the labyrinth structure becomes more complicated, and thus the effect of preventing the resin material 35 from leaking out of the cylindrical portion 30 is further improved.

[0070] Figure 8 Yes means Figure 5 2 is a cross-sectional view of another modified example of the labyrinth structure shown in FIG. As shown in the figure, a convex portion 40 having a width equivalent to the width of the first resist portion 36 and the second resist portion 37 may be formed at the end portion 32e of the cylindrical portion 30 to have the same height as the first resist portion 36 and the second resist portion 37. Thus, by arranging the convex portion 40 between the first resist portion 36 and the second resist portion 37, a more complex labyrinth structure can be formed.

[0071] <Implementation method 2>

[0072] Fig.12 1 is a cross-sectional view schematically showing a state in which a conventional sensor unit 100 is mounted on a tube 51 which is an air intake passage opened and closed by a valve 50. As shown in the figure, in the conventional sensor unit 100, in order to improve the responsiveness when measuring the temperature of the fluid to be measured flowing in the tube 51, the front end of the cylindrical body 130 is inserted through an insertion hole formed in the side wall of the tube 51 and arranged in the tube 51.

[0073] In contrast, Figure 3The sensor unit 10 shown in the figure does not protrude the cylindrical portion 30 into the tube 51 in order to improve productivity, transportability, and operability, but measures the temperature of the fluid to be measured flowing in the tube 51. Therefore, in order to improve the responsiveness in the temperature measurement, it is necessary to efficiently take the fluid flowing in the tube 51 into the cylindrical portion 30. Therefore, in this embodiment, a method for efficiently taking the fluid in the tube 51 to be measured into the cylindrical portion 30 is described.

[0074] Fig. 9 It is a cross-sectional view schematically showing a state where the sensor unit 60 according to the present embodiment is attached to the pipe 51 .

[0075] There is a pressure difference in the pipe 51 before and after the valve 50, with the pressure on the upstream side becoming higher and the pressure on the downstream side becoming lower. Fig. 9 As shown in FIG. 1 , by providing a bypass that connects the front and rear of the valve 50 and includes the cylindrical portion 30 as a part thereof in the sensor unit 60, the fluid in the tube 51 is introduced into the cylindrical portion 30 as shown by the arrow, thereby forming a flow of the fluid. Since the fluid (measurement object) in the tube 51 actively enters the cylindrical portion 30, even if the temperature sensor 34 is not protruded into the tube, the measurement sensitivity can be improved. The structure of the sensor unit 60 is described below.

[0076] The housing 20 has a discharge port 61 that opens at a position different from the cylindrical portion 30 and communicates with the inside of the tube 51, and a connecting passage 62 that connects the discharge port 61 with the cylindrical portion 30. The cylindrical portion 30 has a protective portion 65 filled with a resin material 35 that contacts the substrate 33, and a space portion 64 between the external opening 31 that communicates with the inside of the tube 51 and the protective portion 65, which is not filled with the resin material 35. The connecting passage 62 communicates with the space portion 64.

[0077] The external opening 31 and the discharge port 61 in the sensor unit 60 can be connected to the tube 51 . When connected to the tube 51 , the external opening 31 is connected to a position in the tube 51 that is upstream of the discharge port 61 in the fluid flow.

[0078] Fig. 9 The figure shows the mounting structure of a tube 51 through which a fluid flows and a sensor unit 60 capable of measuring the temperature of the fluid. The tube 51 has a valve 50 capable of adjusting the flow rate of the fluid, a first opening 52 located on the upstream side of the flow of the fluid with the valve 50 interposed therebetween, and a second opening 53 located on the downstream side of the flow of the fluid with the valve 50 interposed therebetween. The external opening 31 in the sensor unit 60 is connected to the first opening 52, and the outlet 61 is connected to the second opening 53.

[0079] like Fig. 9As shown, an external opening 31 is provided before and after the valve 50, that is, on the upstream side of the fluid flow, and a discharge port 61 is provided on the downstream side, whereby the fluid in the tube 51 is taken into the space 64. Thus, even if the temperature sensor 34 is arranged at a position deviating from the inside of the tube 51, the temperature of the fluid can be measured with the same accuracy and responsiveness as when it is arranged in the tube 51. Fig. 9 , a structure in which the external opening 31 and the discharge port 61 are directly connected to the first opening 52 and the second opening 53 of the tube 51 is shown. However, the external opening 31 and the discharge port 61 do not need to be directly connected to the first opening 52 and the second opening 53, and it is sufficient as long as they are communicated with the first opening 52 and the second opening 53, respectively. For example, a structure in which the external opening 31 and the discharge port 61 are connected to the first opening 52 and the second opening 53, respectively, via passages may also be adopted.

[0080] For example, if two places where gas enters and there is a pressure difference are connected by a tube or the like, the gas flows in the tube from the side with higher pressure to the side with lower pressure. Since a pressure difference occurs before and after the valve 50 in the tube 51, the first opening 52 and the second opening 53 are provided before and after the valve 50, and the external opening 31 and the discharge port 61 are connected to the first opening 52 and the second opening 53, so that a part of the fluid in the tube 51 forms a flow path 73 that flows through the external opening 31, the space 64, the connecting passage 62, and the discharge port 61 in the sensor unit 60. Therefore, the fluid flowing in the tube 51 can be efficiently taken into the cylindrical portion 30, and the responsiveness in temperature measurement can be improved.

[0081] In addition, Fig. 9 In the figure, for the sake of convenience, the external opening 31, the discharge port 61, the first opening 52, and the second opening 53 are shown larger. However, in reality, the flow path 73 formed in the sensor unit 60 is designed so that the flow rate Q' of the fluid flowing in the flow path 73 formed in the sensor unit 60 becomes a flow rate (less than 0.1%) sufficiently small relative to the flow rate Q of the fluid flowing in the tube 51. Therefore, the formation of the flow path 73 does not affect the throttling of the valve 50 that adjusts the amount of the fluid flowing in the tube 51.

[0082] When the pressure of the first opening 52 upstream of the valve 50 is p1, the pressure of the second opening 53 downstream of the valve 50 is p2, and the density of the fluid is ρ, Q and Q' are respectively expressed by the following equations using the Bernoulli equation. Therefore, if α'·A' is less than 0.1% of α·A, Q' can be less than 0.1% of Q.

[0083] If Q' is set to be less than 0.1% of Q, the installation of the sensor unit 60 will not affect the operation of the engine. In addition, for example, in the engine of a 150cc two-wheeled vehicle, about 1cc flows per second at idle speed, so from the perspective of the heat capacity of the temperature sensor 34 and the amount of heat transfer relative to it, it is also possible to perform temperature measurement without problems in terms of time constant. In addition, when the sensor unit 60 is installed in the pipe 51, it is sufficient to set the optimal conditions according to the conditions of the engine, etc.

[0084] Q = α·A[2(p1-p2) / ρ] 1 / 2

[0085] (α: outflow coefficient [varies according to the opening ratio of the valve 50], A: cross-sectional area of ​​the tube 51)

[0086] Q′=α′·A′[2(p1-p2) / ρ] 1 / 2

[0087] (α': outflow coefficient [varies according to the opening ratio of the valve 50], A': cross-sectional area of ​​the first opening 52)

[0088] <Modification>

[0089] Fig.10 1 is a cross-sectional view schematically showing a state where a sensor unit 70 as a modified example of the sensor unit 60 of the present embodiment is mounted on the tube 51. The sensor unit 70 is different from the sensor unit 60 in that a recess 72 is provided in which a part of the wall of the flow path (the wall on the tube 51 side) is mounted.

[0090] The housing 74 has a recessed portion 72 extending in a direction away from the cylindrical portion 30 in a part of its outer surface. In addition, when the sensor unit 60 is mounted on the tube 51, a part of the recessed portion 72 is blocked by the wall between the first opening 52 and the second opening 53 of the tube 51, and a discharge port 61 is formed in a portion where the recessed portion 72 is not blocked. In the present embodiment, the discharge port 61 is provided at the end of the recessed portion 72 on the opposite side of the cylindrical portion 30.

[0091] In the sensor unit 70 of this embodiment, a portion of the wall constituting the flow path 73 is formed by the tube 51, that is, the flow path 73 from the space portion 64 to the discharge port 61 is formed by the outer side surface of the tube 51 and the recessed portion 72 of the sensor unit 70. By adopting this structure, it is unnecessary to form the connecting passage 62 of the housing 20 in the housing 74 (see Fig. 9 ) such as a passage (lateral hole). Therefore, it is easy to manufacture using a mold. Alternatively, there is no need to install a cover member in the recess 72 to form a passage such as the connecting passage 62, which can prevent an increase in component costs.

[0092] exist Fig.10In the mounting structure shown, there are provided: a tube 51 through which a fluid flows; and a sensor unit 70 mounted on the tube 51 and capable of measuring the temperature of the fluid, the tube 51 having: a valve 50 capable of adjusting the flow rate of the fluid; a first opening 52 located on the upstream side of the flow of the fluid with the valve 50 interposed therebetween; and a second opening 53 located on the downstream side of the flow of the fluid with the valve 50 interposed therebetween, and the sensor unit 70 is arranged in such a manner that the recess 72 is tightly covered by the tube 51. Furthermore, the tube 51 has the second opening 53 at a position facing the recess 72 when the sensor unit 70 is arranged thereon. In the present embodiment, the second opening 53 is provided at a position of the tube 51 corresponding to the end of the recess 72 on the side away from the cylindrical portion 30, and the discharge port 61 is provided at the end of the recess 72 on the opposite side of the cylindrical portion 30.

[0093] Industrial availability

[0094] The present invention can be applied to a sensor unit including a temperature detection element, and in particular, a sensor unit that detects the intake air temperature in an intake passage of an engine of a vehicle.

[0095] [Explanation of Reference Numerals]

[0096] 10, 60, 70: Sensor unit

[0097] 20: Shell

[0098] 21: Upper part of the main body

[0099] 22: Shell body

[0100] 23a23b: threaded hole

[0101] 24: Throttle valve sensor

[0102] 25: Connection hole

[0103] 26: Coupler

[0104] 27: Terminal

[0105] 30: Cylindrical part

[0106] 31: External side opening

[0107] 32: Internal side opening

[0108] 32e: End

[0109] 33: Substrate

[0110] 33a: Side 1

[0111] 34: Temperature sensor

[0112] 35: Resin material

[0113] 36: First resist portion

[0114] 36a: Cu pattern

[0115] 36b: Resist film

[0116] 37: Second resist portion

[0117] 37a: Cu pattern

[0118] 37b: Resist film

[0119] 38: Groove

[0120] 39: Third resist portion

[0121] 39a: Cu pattern

[0122] 39b: Resist film

[0123] 40: convex part

[0124] 41: Internal Space

[0125] 50: Valve

[0126] 51: Tube

[0127] 52: First opening

[0128] 53: Second opening

[0129] 61: Exhaust port

[0130] 62: Connection Path

[0131] 64: Space Department

[0132] 65: Protection Department

[0133] 72: Concave

[0134] 73: Flow path

[0135] 74: Shell

[0136] 100: Sensor unit

[0137] 130: Cylindrical body

[0138] 131: Thermistor

[0139] 132: Wire

[0140] 133: Substrate

[0141] 134: Resin material

[0142] 135: Shell

[0143] Q, Q′: flow rate

[0144] p1, p2: pressure

Claims

1. A sensor unit capable of measuring the temperature of a fluid flowing in a pipe, characterized in that: have: a housing having an internal space and a cylindrical portion connecting the internal space with the outside; and The substrate has a temperature sensor mounted on the first surface. The substrate is disposed in the inner space of the housing. The outer opening of the outer side of the cylindrical portion can be connected to the inside of the tube, The inner opening of the inner space side of the cylindrical portion is blocked by the first surface of the substrate, The temperature sensor is arranged inside the cylindrical portion. The cylindrical portion has a protective portion filled with a resin material covering the temperature sensor. The housing has: a discharge port that opens at a position different from the outer opening of the cylindrical portion and is connected to the tube; and A connecting passage connects the discharge port to the cylindrical portion, The cylindrical portion has in its interior: the protection portion being in contact with the substrate and filled with the resin material; and a space portion between the outer opening and the protection portion and not filled with the resin material, The connection passage communicates with the space portion.

2. The sensor unit according to claim 1, characterized in that The external opening and the discharge port can be connected to the tube. In a state where the external opening and the discharge port are connected to the tube, the external opening is located upstream of the discharge port with respect to the fluid flowing in the tube.

3. The sensor unit according to claim 2, characterized in that The housing has a recessed portion extending in a direction away from the cylindrical portion on a portion of its outer surface. When attached to the pipe, the discharge port is formed by a part of the recessed portion.

4. The sensor unit according to claim 3, characterized in that The discharge port is provided at an end portion of the recessed portion on the opposite side to the cylindrical portion.

5. The sensor unit according to any one of claims 1 to 4, characterized in that The first surface of the substrate is provided with: a first resist portion formed along the outer peripheral shape of the inner opening of the cylindrical portion, and a second resist portion formed along the inner peripheral shape of the cylindrical portion. An end portion of the cylindrical portion that is open on the inner side is arranged between the first resist portion and the second resist portion.

6. The sensor unit according to claim 5, characterized in that A groove is provided at the end of the cylindrical portion in the inner opening, A third resist portion is provided at a position facing the groove portion between the first resist portion and the second resist portion on the first surface of the substrate.

7. The sensor unit according to any one of claims 1 to 4, characterized in that The resin material has a thermal conductivity of 0.3 W / m·K or more in the extension direction of the cylindrical portion.

8. A sensor unit installation structure, characterized in that: have: a tube for fluid flow; and The sensor unit according to any one of claims 1 to 7, which is mounted on the tube and is capable of measuring the temperature of the fluid. The tube has: a valve capable of adjusting the flow rate of the fluid; and a first opening located on the upstream side of the flow of the fluid with the valve interposed therebetween; and a second opening located on the downstream side of the flow of the fluid with respect to the valve, The first opening is connected to the external opening, and the second opening is connected to the discharge port.

9. A sensor unit installation structure, characterized in that: have: a tube for fluid flow; and The sensor unit according to claim 3 is mounted on the tube and is capable of measuring the temperature of the fluid. The tube has: a valve capable of adjusting the flow rate of the fluid; and a first opening located on the upstream side of the flow of the fluid with the valve interposed therebetween; and a second opening located on the downstream side of the flow of the fluid with respect to the valve, In a state where the sensor unit is arranged so that the concave portion is covered by the tube, the first opening is connected to the outer opening, and the second opening faces the concave portion.

10. The sensor unit mounting structure according to claim 9, wherein: The second opening is provided at a portion of the tube corresponding to an end of the recessed portion on a side away from the cylindrical portion. The discharge port is provided at an end portion of the recessed portion on the opposite side to the cylindrical portion.

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