JP7391220B2 - Sensor unit and its mounting structure - Google Patents

Description

The present invention relates to a sensor unit equipped with a temperature detection element, and particularly to a sensor unit that detects the temperature of intake air in an intake tract of a vehicle engine, and its mounting structure.

The engine throttle body device described in Patent Document 1 has a housing that is screwed to a throttle body having an intake passage that is opened and closed by a throttle valve, and a distal end that penetrates a side wall of the throttle body and is closed to the intake passage. A pipe (hollow cylindrical body) is integrally formed, and the intake temperature sensor is housed with the sensor element in close contact with the inner surface of the tip of the pipe. A synthetic resin is potted into the hollow part of the pipe after the intake air temperature sensor is housed therein.

However, since the synthetic resin is poured from the opening side of the hollow cylinder toward the bottomed tip end, the air existing inside the hollow cylinder is sent to the tip side. Therefore, bubbles are likely to form around the sensor element, and filling with the synthetic resin may become uneven. For this reason, there is a problem that the responsiveness of measuring the intake air temperature is low, and measurement performance tends to vary due to differences in the filling state of each product.

Therefore, Patent Document 2 describes a sensor unit that suppresses the air inside the hollow cylindrical body from remaining at the tip 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 sensing element disposed inside the distal end of the cylindrical body in the extending direction. has a hole penetrating the wall of the tip, and the inside of the cylindrical body is filled with a resin material. With this configuration, responsiveness of temperature measurement can be ensured and variations in measurement performance can be suppressed.

However, in the temperature detection section of the sensor unit of Patent Document 2, a thermistor is disposed at the inner tip of a cylindrical body that protrudes elongately from the housing. For this reason, the thermistor is electrically connected to a substrate disposed within the housing by the extended wiring. With this structure, it is difficult to connect the lead wires and the board, causing an increase in manufacturing costs. Furthermore, since the temperature sensing portion protrudes from the housing, there is a problem that the package becomes bulky and transport efficiency is reduced, and the long and narrow cylindrical body is easily damaged during assembly or by falling or colliding. Since the thermistor measures temperature through the case and the resin material, there is a problem in that it takes some time to respond to temperature changes.

Japanese Patent Application Publication No. 2004-124874 JP 2019-020251 Publication

SUMMARY OF THE INVENTION Therefore, the present invention aims to provide a sensor unit that has a temperature detection section with a simple structure, can reduce manufacturing costs compared to the conventional one, has high transportation efficiency, and is not easily damaged by shocks caused by drops or collisions.

The present invention provides a sensor unit capable of measuring the temperature of a fluid flowing inside a pipe, which includes a housing having an internal space and a cylindrical part that communicates the internal space with the outside, and a temperature sensor mounted on a first surface. and a substrate disposed in the internal space of the housing, an external opening on the external side of the cylindrical part can be connected to the inside of the pipe, and an external opening on the external side of the cylindrical part on the internal space side of the cylindrical part. The inner opening is closed by the first surface of the substrate, the temperature sensor is disposed inside the cylindrical part, and the cylindrical part has a protective part filled with a resin material to cover the temperature sensor. Provided is a sensor unit comprising:

By mounting the temperature sensor on the first surface of the board, there is no need to route wiring that electrically connects the temperature sensor and the board, making positioning and assembly of the temperature sensor easier. Therefore, the manufacturing cost of the sensor unit can be suppressed. Furthermore, since the temperature sensor can be sealed using a small amount of resin material, the time required for curing the resin material can be shortened, and the sensor unit can be made lighter. The reduced weight reduces the force applied in the event of a collision, resulting in a sensor unit that is resistant to impact and difficult to break. Furthermore, since the cylindrical portion does not need to have a long and narrow shape projecting from the housing, bubbles are less likely to be generated when filling and sealing with the resin material. This improves the accuracy and responsiveness in temperature measurement by the sensor unit.

The housing has a discharge port opened at a position different from the external opening of the cylindrical portion and connected to the pipe, and a connection path that communicates the discharge port and the cylindrical portion, The inside of the cylindrical part is filled with the protective part filled with the resin material and in contact with the substrate, and the resin material between the external opening leading into the pipe and the protective part. The connection path may be in communication with the space.
The external opening and the discharge port are connectable to the pipe, and in the state where the external opening and the discharge port are connected to the pipe, the external opening is more connected to the pipe than the discharge port. It is preferable that it communicates with the upstream side of the fluid flowing therein.

With the above configuration, a part of the fluid flowing inside the pipe is taken into the space from the external opening of the cylindrical part, and a flow of the fluid is formed that reaches the discharge port via the connecting path. Further, in a state where the external opening and the discharge port are connected to the pipe, the external opening is communicated upstream of the flow of the fluid in the pipe from the discharge port, so that the fluid flows smoothly. Therefore, the accuracy and responsiveness of the temperature measurement of the fluid in the pipe by the temperature sensor in the cylindrical part of the sensor unit are improved.

The housing may have a recess extending in a direction away from the cylindrical portion on a part of its outer surface, and the discharge port may be formed by a part of the recess when the housing is attached to the pipe. good. The discharge port may be provided at an end of the recess opposite to the cylindrical portion.
When the housing is attached to the pipe, the connection path can be easily formed by covering the recess with the outer surface of the pipe. Further, by providing the discharge port at the opposite end of the cylindrical portion, the connecting path can be lengthened, so that the flow of the fluid in the sensor unit becomes smooth.

The first surface of the substrate includes 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. It is preferable that the cylindrical portion is provided with an end portion of the inner opening in the cylindrical portion between the first resist portion and the second resist portion.
With this configuration, a labyrinth structure is formed in which the end of the inner opening is sandwiched between the first resist portion and the second resist portion. Therefore, when covering and sealing the temperature sensor inside the cylindrical part with a resin material, the resin material passes from the inside of the cylindrical part into the internal space of the housing through the gap between the substrate and the end of the cylindrical part. The flow can be suppressed.

A groove is provided at the end of the inner opening, and a third resist portion is provided at a position opposite to the groove between the first resist portion and the second resist portion on the first surface of the substrate. You can.
Since a complex labyrinth structure can be formed by fitting the groove part and the third resist part, it is possible to more effectively prevent the sealing material from flowing into the inner space of the housing.

It is preferable that the resin material has a thermal conductivity of 0.3 (W/m·K) or more in the extending direction of the cylindrical portion.
By using a resin material that has high thermal conductivity in the direction of extension of the cylindrical portion, even if the thickness of the resin material that protects the temperature sensor is increased, the temperature of the fluid will be transmitted to the temperature sensor through the resin material. It becomes easier. Therefore, the temperature of the fluid can be measured with good responsiveness while sealing with a resin material having a thickness sufficient for protection from corrosive gases while suppressing a decrease in sensitivity of the temperature sensor.

The present invention includes a pipe through which a fluid flows, and a sensor unit of the present invention that is attached to the pipe and is capable of measuring the temperature of the fluid, and the pipe is capable of adjusting the flow rate of the fluid. A valve, a first opening located on the upstream side of the flow of the fluid across the valve, and a second opening located on the downstream side of the flow of the fluid across the valve. , providing a mounting structure for a sensor unit, wherein the first opening is connected to the external opening, and the second opening is connected to the discharge port.

The pressure inside the pipe is high upstream of the valve and low downstream of the valve. Therefore, the first opening and the second opening are provided so that the valve is sandwiched between the first opening and the second opening, the external opening is connected to the first opening, and the second opening is connected to the outside opening. A fluid flow is created within the sensor unit by connecting an outlet to the sensor unit. Thereby, the fluid in the pipe to be measured can be efficiently taken into the space of the cylindrical part. Therefore, accuracy and responsiveness in measuring the temperature of the fluid in the pipe is improved.

The present invention includes a pipe through which a fluid flows, and a sensor unit of the present invention, which is attached to the pipe and includes a housing having a concave portion capable of measuring the temperature of the fluid, and the sensor unit includes: a valve capable of adjusting the flow rate of the fluid; a first opening located on the upstream side of the flow of the fluid to be measured across the valve; and a first opening located on the downstream side of the flow of the fluid to be measured across the valve. a second opening located at the outer side, and in a state in which the sensor unit is arranged such that the concave portion is covered by the pipe, the first opening is connected to the external opening, and the second opening is connected to the outside opening. The present invention provides a mounting structure for a sensor unit, in which a portion of the sensor unit faces the recess.
The second opening is provided at a location of the pipe corresponding to an end of the recess on the side away from the cylindrical portion, and the outlet is provided at a location on the opposite side of the cylindrical portion in the recess. It may be provided at the end.

By covering the concave portion of the housing of the sensor unit of the present invention with a pipe to form a communication path, it is not necessary to form a tubular structure for the communication path in the housing alone. Therefore, manufacturing of the housing constituting the sensor unit becomes easy. Further, by providing the discharge port at the opposite end of the cylindrical portion, the connecting path can be lengthened and the flow of the fluid can be made smooth.

According to the present invention, the manufacturing cost can be kept low by simplifying the process more than before, and the sensor unit has high transportation efficiency, is resistant to drops and collisions during assembly and movement, and is easy to handle. can be provided.

A side view showing the configuration of a sensor unit according to Embodiment 1. A plan view showing the configuration of a sensor unit according to Embodiment 1. A cross-sectional view schematically showing a state in which the sensor unit according to Embodiment 1 is attached to a pipe through which a fluid whose temperature is to be measured flows. Cross-sectional view of the cylindrical body in Embodiment 1 A cross-sectional view showing an enlarged portion B of the cylindrical body shown in FIG. 4, which is marked with a circle. A perspective view schematically showing a disassembled state of the cylindrical body and the substrate including the first resist section and the second resist section in Embodiment 1. A sectional view showing a modification of the labyrinth structure shown in FIG. 5 A sectional view showing another modification of the labyrinth structure shown in FIG. 4 A cross-sectional view schematically showing a state in which a sensor unit according to Embodiment 2 is attached to a pipe. A sectional view schematically showing a state in which a modified example of the sensor unit according to Embodiment 2 is attached to a pipe. Side view showing the configuration of a conventional sensor unit Cross-sectional view schematically showing a conventional sensor unit attached to a pipe

<Embodiment 1>
Embodiments of the present invention will be described below with reference to the drawings. In each figure, the same members are given the same numbers, and descriptions thereof will be omitted as appropriate.
FIG. 1 is a side view showing the configuration of a sensor unit 10 according to this embodiment, and FIG. 2 is a plan view showing the configuration of the sensor unit 10. In each figure, XYZ coordinates are shown as reference coordinates. The Z direction is along the extension direction of the cylindrical portion 30, and the XY plane is a plane perpendicular to the Z direction. In the following description, the state viewed along the Z direction may be referred to as a planar view. Moreover, although the upper and lower sides of FIG. 1 are described as vertical directions, the orientation of the sensor unit 10 is not limited to this.

The sensor unit 10 is attached to a throttle body (not shown) used in the engine of a motorcycle, automobile, or other vehicle. The throttle body has an intake passage (pipe) that is opened and closed by a throttle valve (not shown), and the sensor unit 10 electrically detects the intake air temperature within the intake passage. The sensor unit 10 is implemented in a manner that includes means for detecting the opening/closing of a throttle valve and the pressure within the intake tract in addition to the temperature within the intake tract, but below, the configuration related to temperature measurement will be mainly described.

As shown in FIG. 1 or 2, the sensor unit 10 includes a housing 20 made of synthetic resin. The housing 20 has a housing main body part 22, and a main body upper part 21 that constitutes the upper part of the housing main body part 22 has a shape extending laterally from the housing main body part 22. As shown in FIG. 2, screw holes 23a and 23b are provided on the upper surface of the upper body 21, and the housing 20 is fixed to the throttle body by connecting screws to the mounting surface of the throttle body through these holes. The sensor unit 10 is fixed to the throttle body and is capable of measuring the temperature of the fluid in the intake passage (pipe) of the engine.

FIG. 3 is a cross-sectional view schematically showing a state in which the sensor unit 10 of this embodiment is attached to a pipe 51 that is an intake path that is opened and closed by a valve 50. As shown in the figure, the housing 20 has an internal space 41, and the internal space 41 communicates with the outside through the cylindrical portion 30. The outer opening 31 of the cylindrical portion 30 is connected to a first opening 52 formed in the side wall of the pipe 51, and the inner opening 32 of the cylindrical portion 30 is closed by a substrate 33. Furthermore, a temperature sensor 34 is disposed at a location on the substrate 33 that is inside the cylindrical portion 30 when the internal opening 32 is closed. The fluid in the pipe 51 flows into the cylindrical portion 30 , and the temperature of the fluid flowing in is measured by the temperature sensor 34 .

The housing 20 is provided with a throttle sensor 24 that electrically detects the opening degree of the throttle valve, and the throttle sensor 24 is connected through a connecting hole 25 to a valve shaft (not shown) that supports the throttle valve.

A circuit board common to the throttle sensor 24 and temperature sensor 34 is installed inside the housing 20, and the circuit on this board calculates the opening degree of the throttle valve from the detection result by the throttle sensor 24, and also calculates the temperature. The intake air temperature is calculated from the detection result by the sensor 34.

The housing 20 is provided with a coupler 26 formed into a rectangular tube shape. The coupler 26 is provided with a plurality of terminals 27 electrically connected to the circuit board on the inside of the rectangular tube-shaped portion. Detection signals from the throttle sensor 24, pressure sensor, and temperature sensor 34, and calculation results from the circuit described above are output to a control unit (not shown) connected through a plurality of terminals 27.

FIG. 11 is a side view showing the configuration of a conventional sensor unit 100, and FIG. 12 is a cross-sectional view schematically showing a state in which the sensor unit 100 is attached to a pipe 51 that is an intake path of an engine. As shown in these figures, the conventional sensor unit 100 includes a cylindrical body 130 in which a thermistor 131 is arranged. 130 was placed to measure the temperature of the fluid inside the pipe 51.

As shown in FIGS. 11 and 12, the conventional sensor unit 100 includes an elongated cylindrical body 130 that is inserted into a pipe 51 during measurement, and a thermistor 131 inside the body is connected to a substrate via a lead wire 132. 133. For this reason, when connecting the thermistor 131 to the substrate 133 via the lead wire 132, it is difficult to position the thermistor 131 at a predetermined position, which is one reason for increasing manufacturing costs due to complicated processes. In addition, when the thermistor 131 is placed at a predetermined position at the tip of the cylindrical body 130, air is likely to be drawn in when potting with the resin material 134, and if the resin material 134 to be potted contains air, the accuracy of temperature measurement may be affected. There was a problem that responsiveness decreased. The resin material 134 is potted not only in the vicinity of the thermistor 131 but also in locations within the housing 135 that do not interfere with the operation of the throttle sensor and the like. Therefore, it takes a long time to harden the resin material 134, which causes the sensor unit 100 to become heavy. Furthermore, the cylindrical body 130 protruding from the housing 135 is also a cause of damage caused by unexpected collisions during or after manufacture, and a reduction in transportation efficiency. Furthermore, since the resin material 134 and the cylindrical body 130 exist between the thermistor 131 and the fluid in the pipe 51, the responsiveness in temperature measurement was not sufficient.

Therefore, the sensor unit 10 of this embodiment uses a temperature sensor mounted on a substrate instead of a thermistor. As shown in FIG. 1 or 2, by having a configuration in which the cylindrical portion 30 does not protrude from the housing 20, the manufacturing process is simplified to reduce costs, improve transportation efficiency, reduce the risk of breakage, and improve responsiveness. etc. were realized.

FIG. 4 is a sectional view of the cylindrical portion 30 in this embodiment, and is a sectional view taken along line AA' in FIG. A temperature sensor 34 is mounted on the first surface 33a of the substrate 33.
The sensor unit 10 of this embodiment has a configuration in which a temperature sensor chip is attached directly to the substrate, thereby eliminating the elongated protruding cylindrical body 130 in the conventional sensor unit 100. Therefore, the sensor unit 10 is excellent in terms of manufacturing cost, transportation efficiency, damage risk, and the like.

The substrate 33 is arranged in the internal space 41 of the housing 20 (see FIG. 3). The inner opening 32 on the inner space 41 side of the cylindrical portion 30 is closed by the first surface 33a of the substrate 33. The temperature sensor 34 is arranged inside the cylindrical part 30, and the inside of the cylindrical part 30 is filled with a resin material 35 that covers the temperature sensor 34. With this configuration, only the resin material 35 exists between the temperature sensor 34 and the fluid in the pipe 51. In FIG. 4, a portion of the cylindrical portion 30 is the protective portion 65 filled with the resin material 35, but the entire cylindrical portion 30 may be filled with the resin material 35 as the protective portion 65.

The temperature sensor 34 is a so-called chip-type temperature sensor. Since the chip-type temperature sensor 34 can be mounted on the substrate 33 without using lead wires like a conventional thermistor, manufacturing of the sensor unit 10 is facilitated. 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, manufacturing costs can be reduced compared to the conventional method (see FIG. 12).

The cylindrical part 30 that communicates the internal space 41 with the outside is different from the cylindrical body 130 in the conventional sensor unit 100 shown in FIGS. 11 and 12 when cut along a plane parallel to the XY plane. It has a large cross-sectional area and a short length in the Z direction. For this reason, when the resin material 35 is poured into the cylindrical portion 30, the resin material 35 is difficult to entrain air bubbles. The external 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 is simplified and the temperature responsiveness of the sensor unit 10 can be improved.

The resin material 35 is preferably a resin that is resistant enough to protect the temperature sensor 34 from corrosive gases and has 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 is increased, so that the responsiveness of the sensor unit 10 is improved. From the viewpoint of improving responsiveness to temperature changes, the thermal conductivity of the cylindrical portion 30 in the extension direction (Z direction) is preferably 0.3 (W/m·K) or more, and 1.0 (W/m·K) or more. m·K) or more is more preferable, and 3.0 (W/m·K) or more is even more preferable. Examples of the resin material 35 having resistance and high thermal conductivity include polyurethane resin, epoxy resin, and the like.

FIG. 5 is an enlarged cross-sectional view of the circled portion B of the cylindrical portion 30 in FIG. be. As shown in FIGS. 4 and 5, a first surface 33a on the cylindrical portion 30 side of the main surface of the substrate 33 has a groove formed along the outer circumferential shape of the inner opening 32 of the cylindrical portion 30. A first resist portion 36 and a second resist portion 37 formed along the inner peripheral shape of the cylindrical portion 30 are provided. The 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.

The end 32e of the cylindrical portion 30 and the first surface 33a of the substrate 33 are placed in contact with each other. However, due to variations in the machining accuracy of the end portion 32e and the first surface 33a, and assembly variations when the cylindrical portion 30 and the substrate 33 are assembled, a small gap may be formed between the end portion 32e and the first surface 33a. It is conceivable that this may occur. If such a gap occurs, the resin material 35 may seep into the internal space 41 through the gap, which may cause a problem. With the above configuration, as shown by the thick line in the figure, there is a gap between the first resist section 36 and the inner surface of the cylindrical section 30, and between the end 32e of the cylindrical section 30 and the first surface 33a of the substrate 33. Even if a gap is created between the second resist portion 37 and the outer surface of the cylindrical portion 30, a labyrinth structure having a U-shaped cross section is formed. With this labyrinth structure, the resin material 35 poured into the inside of the cylindrical part 30 is held inside the cylindrical part 30, and the resin material 35 is passed between the substrate 33 and the cylindrical part 30 into the internal space 40 of the housing 20. (See Figure 3).

The first resist portion 36 has a configuration in which a resist film 36b is formed on a Cu pattern 36a made 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 have a height sufficient to prevent the resin material 35 from flowing out. Further, the second resist section 37 also has a configuration in which a resist film 37b is formed on a Cu pattern 37a.

By using the Cu pattern 36a and the Cu pattern 37a formed on the substrate 33, it is possible to form the first resist section 36 and the second resist section 37 with sufficient thickness to form a labyrinth structure. Since a Cu pattern is formed on the surface of the substrate 33, when forming the Cu pattern, a Cu pattern 36a and a Cu pattern 37a are formed in regions corresponding to the first resist section 36 and the second resist section 37. Then, by further forming a resist film 36b and a resist film 37b on the Cu pattern 36a and the Cu pattern 37a, a first resist part 36 and a second resist part 37 having a height of, for example, about 70 μm are formed. can do.

FIG. 6 is a perspective view schematically showing an exploded state of the cylindrical portion 30 and the substrate 33 including the first resist portion 36 and the second resist portion 37 in the embodiment of the present invention. As shown in the figure, a first resist portion 36 and a second resist portion 37, which are annular resist patterns having different diameters, are provided on the first surface 33a of the substrate 33. The inner opening 32 of the cylindrical portion 30 is arranged between the first resist portion 37 and the second resist portion 37 . Thereby, a labyrinth structure can be easily formed on the contact surface between the cylindrical portion 30 and the substrate 33. Therefore, it is possible to easily prevent the resin material 35 (potting material) from leaking out from the cylindrical portion 30 while reducing manufacturing costs. Note that known means such as caulking and screwing can be used to bring the cylindrical portion 30 of the housing 20 and the substrate 33 into close contact with each other.

<Modified example>
FIG. 7 is a sectional view showing a modification of the labyrinth structure shown in FIG. As shown in the figure, a groove 38 is formed at the end 32e of the cylindrical part 30 that contacts the substrate 33, and a resist film 39b is formed on a Cu pattern 39a at a location facing the groove 38 of the substrate 33. A third resist section 39 may be additionally provided. By fitting the third resist portion 39 into the groove portion 38, the labyrinth structure becomes more complicated, so that the effect of preventing leakage of the resin material 35 from the cylindrical portion 30 is further improved.

FIG. 8 is a sectional view showing another modification of the labyrinth structure shown in FIG. As shown in the figure, a convex portion 40 having a width corresponding to the width of the first resist portion 36 and the second resist portion 37 is formed on the end portion 32e of the cylindrical portion 30. It may be formed at the same height as 37. Thereby, by arranging the convex portion 40 between the first resist portion 36 and the second resist portion 37, a more complicated labyrinth structure can be formed.

<Embodiment 2>
FIG. 12 is a cross-sectional view schematically showing a state in which a conventional sensor unit 100 is attached to a pipe 51 that is an intake path that is opened and closed by a valve 50. As shown in the figure, in the conventional sensor unit 100, in order to improve responsiveness when measuring the temperature of the fluid to be measured flowing in the pipe 51, the tip of the cylindrical body 130 is connected to the pipe 51. It was inserted into the pipe 51 through an insertion hole formed in the side wall of the pipe 51 .

On the other hand, in order to improve productivity, transportability, and handling, the sensor unit 10 shown in FIG. Measure the temperature of a fluid. Therefore, in order to improve the responsiveness in temperature measurement, it is necessary to efficiently take the fluid flowing through the pipe 51 into the cylindrical portion 30. Therefore, in this embodiment, a mode for efficiently taking the fluid in the pipe 51 to be measured into the cylindrical portion 30 will be described.

FIG. 9 is a cross-sectional view schematically showing a state in which the sensor unit 60 of this embodiment is attached to the pipe 51.
A difference occurs in the pressure within the pipe 51 before and after the valve 50, with the pressure on the upstream side being high and the pressure on the downstream side being low. Therefore, as shown in FIG. 9, by providing a bypass in the sensor unit 60 that connects the front and back of the valve 50 and includes the cylindrical part 30 as a part, the fluid in the pipe 51 is directed into the cylinder as shown by the arrow. into the shaped portion 30 to form a fluid flow. Since the fluid (measurement target) in the pipe 51 actively enters the cylindrical portion 30, the measurement sensitivity can be improved even if the temperature sensor 34 does not protrude into the pipe. The configuration of the sensor unit 60 will be described below.

The housing 20 has a discharge port 61 that opens at a position different from that of the cylindrical portion 30 and that communicates with the inside of the pipe 51 , and a connecting path 62 that communicates with the discharge port 61 and the cylindrical portion 30 . , a protective part 65 filled with the resin material 35 in contact with the substrate 33, and a space 64 not filled with the resin material 35 between the external opening 31 communicating with the pipe 51 and the protective part 65. It has . The connecting path 62 communicates with the space 64.

In the sensor unit 60 , the external opening 31 and the discharge port 61 can be connected to the pipe 51 , and in a state where the external opening 31 is connected to the pipe 51 , the external opening 31 has a higher flow rate than the discharge port 61 due to the fluid inside the pipe 51 . connected to the upstream position of the flow.

FIG. 9 shows an attachment structure for a pipe 51 through which a fluid flows and a sensor unit 60 capable of measuring the temperature of the fluid. The pipe 51 includes a valve 50 that can adjust the flow rate of the fluid, a first opening 52 located on the upstream side of the fluid flow across the valve 50, and a first opening 52 located on the downstream side of the fluid flow across the valve 50. and a second opening 53 located at. In the sensor unit 60, the external opening 31 is connected to the first opening 52, and the discharge port 61 is connected to the second opening 53.

As shown in FIG. 9, by providing an external opening 31 before and after the valve 50, that is, on the upstream side of the fluid flow, and providing a discharge port 61 on the downstream side, the fluid in the pipe 51 is released into the space 64. It is captured. As a result, even if the temperature sensor 34 is placed outside the pipe 51, the temperature of the fluid can be measured with the same accuracy and responsiveness as when it is placed inside the pipe 51. FIG. 9 shows a configuration 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 pipe 51. 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 as long as they communicate with the first opening 52 and the second opening 53, respectively. good. For example, a configuration may be adopted in which the external opening 31 and the discharge port 61 are connected to the first opening 52 and the second opening 53 through passages, respectively.

For example, if two places that contain gas and have different pressures are connected using a pipe, the gas will flow through the pipe 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 pipe 51, a first opening 52 and a 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. By communicating with the two openings 53, a flow path 73 is formed through which a part of the fluid in the pipe 51 flows through the external opening 31, the space 64, the connection path 62, and the discharge port 61 in the sensor unit 60. Therefore, the fluid flowing through the pipe 51 can be efficiently taken into the cylindrical portion 30, and the responsiveness in temperature measurement can be improved.

In addition, in FIG. 9, for convenience of explanation, the external opening 31, the discharge port 61, the first opening 52, and the second opening 53 are illustrated in a large size. However, in reality, the flow rate Q' of the fluid flowing through the flow path 73 formed in the sensor unit 60 is sufficiently small (0.1% or less) compared to the flow rate Q of the fluid flowing inside the pipe 51. The flow path 73 formed in the sensor unit 60 is designed so that. Therefore, the formation of the flow path 73 does not affect the restriction of the valve 50 that adjusts the amount of fluid flowing through the pipe 51.

If the pressure at the first opening 52 upstream of the valve 50 is p1, the pressure at the second opening 53 downstream of the valve 50 is p2, and the density of the fluid is ρ, then Q and Q' are each expressed as follows using Bernoulli's formula. Expressed by the formula. Therefore, if α'·A' is made to be 0.1% or less of α·A, Q' can be made to be 0.1% or less of Q.
If Q' is set to 0.1% or less of Q, the installation of the sensor unit 60 will not affect the operation of the engine. Further, for example, in a 150 cc two-wheeled vehicle engine, about 1 cc flows per second when idling, so it is possible to measure the temperature without any problem in terms of time constant from the viewpoint of the heat capacity of the temperature sensor 34 and the amount of heat transferred thereto. Note that when attaching the sensor unit 60 to the pipe 51, optimal conditions may be set according to engine conditions and the like.
Q=α・A[2(p1-p2)/ρ] ^1/2
(α: outflow coefficient [varies depending on the opening ratio of the valve 50], A: cross-sectional area of the pipe 51)
Q'=α'・A'[2(p1-p2)/ρ] ^1/2
(α': outflow coefficient [varies depending on the opening ratio of the valve 50], A': cross-sectional area of the first opening 52)

<Modified example>
FIG. 10 is a cross-sectional view schematically showing a state in which a sensor unit 70, which is a modified example of the sensor unit 60 of this embodiment, is attached to a pipe 51. The sensor unit 70 differs from the sensor unit 60 in that it includes a recess 72 in which a part of the wall of the flow path (the wall on the pipe 51 side) is removed.

The housing 74 has a recess 72 extending in a direction away from the cylindrical portion 30 on a part of its outer surface. In a state where the sensor unit 60 is attached to the pipe 51, a part of the recess 72 is closed by the wall between the first opening 52 and the second opening 53 of the pipe 51, and the recess 72 is closed. A discharge port 61 is formed at a location where the discharge port 61 is not covered. In this embodiment, the discharge port 61 is provided at the end of the recess 72 on the opposite side of the cylindrical portion 30 .

In the sensor unit 70 of this embodiment, a part of the wall constituting the flow path 73 is constituted by the pipe 51. In other words, the outer surface of the pipe 51 and the recess 72 of the sensor unit 70 connect the space 64 to the discharge port 61. A flow path 73 is formed. With this configuration, it is not necessary to form a passage (horizontal hole) in the housing 74 like the connecting passage 62 (see FIG. 9) of the housing 20. Therefore, it becomes easy to manufacture using a mold. Alternatively, there is no need to attach a lid member to the recess 72 to form a passage such as the connecting passage 62, and an increase in parts costs can be prevented.

The mounting structure shown in FIG. 10 includes a pipe 51 through which a fluid flows and a sensor unit 70 that is attached to the pipe 51 and can measure the temperature of the fluid, and the pipe 51 is capable of adjusting the flow rate of the fluid. a first opening 52 located on the upstream side of the fluid flow across the valve 50, and a second opening 53 located on the downstream side of the fluid flow across the valve 50. The sensor unit 70 is arranged so that the recess 72 is closely covered by the pipe 51. The pipe 51 has a second opening 53 at a location facing the recess 72 when the sensor unit 70 is placed. In the present embodiment, the second opening 53 is provided at a location of the pipe 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 in the cylindrical portion of the recess 72 . 30 at the opposite end.

INDUSTRIAL APPLICATION This invention is applicable to the sensor unit provided with the temperature detection element, and especially to the sensor unit which detects the intake air temperature in the intake path of the engine of a vehicle.

10, 60, 70: Sensor unit 20: Housing 21: Main body upper part 22: Housing main body parts 23a, 23b: Screw hole 24: Throttle sensor 25: Connection hole 26: Coupler 27: Terminal 30: Cylindrical part 31: External opening 32: Internal opening 32e: End 33: Substrate 33a: First surface 34: Temperature sensor 35: Resin material 36: First resist portion 36a: Cu pattern 36b: Resist film 37: Second resist portion 37a: Cu pattern 37b : Resist film 38 : Groove 39 : Third resist part 39a : Cu pattern 39b : Resist film 40 : Convex part 41 : Internal space 50 : Valve 51 : Pipe 52 : First opening 53 : Second opening 61 : Discharge port 62 : Connection path 64 : Space part 65 : Protective part 72 : Recessed part 73 : Channel 74 : Housing 100 : Sensor unit 130 : Cylindrical body 131 : Thermistor 132 : Lead wire 133 : Substrate 134 : Resin material 135 : Housing Q, Q': Flow rate p1, p2: Pressure

Claims (11)

In a sensor unit that can measure the temperature of fluid flowing inside a pipe,
A housing having an internal space and a cylindrical part that communicates the internal space with the outside;
A board on which a temperature sensor is mounted on the first surface,
the substrate is disposed in an internal space of the housing;
The external opening on the external side of the cylindrical part is connectable to the inside of the pipe,
The inner opening on the inner space side of the cylindrical part is closed by the first surface of the substrate,
The temperature sensor is arranged inside the cylindrical part,
The inside of the cylindrical part has a protective part filled with a resin material that covers the temperature sensor,
The housing includes:
an outlet connected to the pipe and opened at a position different from the external opening of the cylindrical part;
comprising a connecting path that communicates the discharge port and the cylindrical part,
The cylindrical part has inside thereof,
the protective portion filled with the resin material and in contact with the substrate;
a space portion between the external opening and the protective portion that is not filled with the resin material;
A sensor unit characterized in that the connecting path communicates with the space . The external opening and the outlet can be connected to the pipe,
The external opening and the discharge port are connected to the pipe, and the external opening is located upstream of the fluid flowing in the pipe, with respect to the discharge port. sensor unit. The housing has a recessed part extending away from the cylindrical part on a part of its outer surface,
The sensor unit according to claim 1 or 2 , wherein the discharge port is formed by a part of the recess when the sensor unit is attached to the pipe. The sensor unit according to claim 3 , wherein the discharge port is provided at an end of the concave portion opposite to the cylindrical portion. The first surface of the substrate includes 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. Department and,
The sensor unit according to any one of claims 1 to 4 , wherein an end of an internal opening in the cylindrical part is arranged between the first resist part and the second resist part. In a sensor unit that can measure the temperature of fluid flowing inside a pipe,
A housing having an internal space and a cylindrical part that communicates the internal space with the outside;
A board on which a temperature sensor is mounted on the first surface,
the substrate is disposed in an internal space of the housing,
The external opening on the external side of the cylindrical part is connectable to the inside of the pipe,
The inner opening on the inner space side of the cylindrical part is closed by the first surface of the substrate,
The temperature sensor is arranged inside the cylindrical part,
The inside of the cylindrical part has a protective part filled with a resin material that covers the temperature sensor,
The first surface of the substrate includes 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. Department and,
A sensor unit characterized in that an end portion of the inner opening of the cylindrical portion is disposed between the first resist portion and the second resist portion. A groove is provided at the end of the cylindrical part in the inner opening,
7. The sensor unit according to claim 5, wherein a third resist section is provided at a position facing the groove between the first resist section and the second resist section on the first surface of the substrate. The sensor unit according to any one of claims 1 to 7, wherein the resin material has a thermal conductivity of 0.3 (W/m·K) or more in the extending direction of the cylindrical portion. comprising: a pipe through which a fluid flows; and a sensor unit according to any one of claims 1 to 5, which is attached to the pipe and is capable of measuring the temperature of the fluid;
The pipe includes a valve capable of adjusting the flow rate of the fluid, a first opening located on the upstream side of the flow of the fluid across the valve, and a first opening located on the downstream side of the flow of the fluid with the valve in between. a second opening located on the side;
A mounting structure for a sensor unit, wherein the first opening is connected to the external opening, and the second opening is connected to the discharge port. comprising: a pipe through which a fluid flows; and a sensor unit according to claim 3 , which is attached to the pipe and is capable of measuring the temperature of the fluid;
The pipe includes a valve capable of adjusting the flow rate of the fluid, a first opening located on the upstream side of the flow of the fluid across the valve, and a first opening located on the downstream side of the flow of the fluid with the valve in between. a second opening located on the side;
In a state in which the sensor unit is arranged so that the recess is covered by the pipe, the first opening is connected to the external opening, and the second opening faces the recess. mounting structure. The second opening is provided at a location of the pipe corresponding to an end of the concave portion on a side remote from the cylindrical portion,
The sensor unit mounting structure according to claim 10, wherein the discharge port is provided at an end of the recess opposite to the cylindrical portion.

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