JP6213652B2 - AIR FLOW MEASURING DEVICE AND MANUFACTURING METHOD OF AIR FLOW MEASURING DEVICE - Google Patents

Description

  The present invention relates to an air flow rate measuring device that is disposed in an intake passage to an engine and measures the flow rate of air taken into the engine.

  Conventionally, a part of the air that is arranged in the intake passage to the engine and flows through the intake passage is taken in, and in the flow rate sensor, the heat generation of the heating element and the heat transfer phenomenon between the taken-in air are generated. 2. Description of the Related Art Thermal air flow measurement devices that measure the flow rate of air taken into an engine are known.

  Further, Patent Document 1 discloses an air flow rate measuring device equipped with an intake air temperature sensor and a humidity sensor in addition to a flow rate sensor.

However, in the air flow rate measuring device of Patent Document 1, the flow path in which the flow sensor is arranged is different from the flow path in which the humidity sensor is arranged. For this reason, the connection mode to the external device is greatly different for each sensor, and the wiring and assembly process are complicated.
When the number and type of sensors other than the flow rate sensor are selected and assembled for each product, there arises a problem that the housing structure and the assembling process of the air flow measuring device have to be greatly changed.

Japanese Patent No. 5178388

  The present invention has been made to solve the above-described problems, and its object is to simplify an assembly process when assembling each sensor in an air flow rate measuring device equipped with an intake air temperature sensor and a humidity sensor. It is an object of the present invention to provide a structure and a manufacturing method that can be manufactured. Furthermore, it is to prevent other sensors from being affected by the heat generated by the flow sensor.

The air flow rate measuring device according to the first invention of the present application includes a housing, a flow rate sensor, and a plurality of sensors other than the flow rate sensor.
The housing is formed with a bypass flow path that takes in part of the air flowing inside the duct and a sub bypass flow path that branches off from the bypass flow path and takes in a part of air that flows through the bypass flow path. Yes.
The flow rate sensor is disposed in the sub-bypass channel, and generates an electrical signal corresponding to the flow rate of air in the duct by heat generation from the heating element and heat transfer with the air passing through the sub-bypass channel.

  A plurality of sensors other than the flow sensor are for measuring a physical quantity of air in the duct, and are an intake air temperature sensor for measuring the temperature in the duct, a humidity sensor for measuring the humidity in the duct, And a pressure sensor (6) for measuring the pressure in the duct (D).

The flow sensor and the plurality of sensors are modularized together with a circuit module containing a circuit board and integrated as a single sensor assembly, and this sensor assembly is assembled to the housing so that it is installed in the sub-bypass channel. Has been.
Furthermore, the humidity sensor is disposed upstream of the flow rate sensor.
According to the second invention of the present application, the intake air temperature sensor is arranged upstream of the flow rate sensor and the humidity sensor .
In the manufacturing method of the air flow rate measuring device according to the third invention of the present application, an intake air temperature sensor for measuring the temperature in the duct and a humidity sensor for measuring the humidity in the duct are used as a plurality of sensors. The plurality of sensors, together with the circuit module incorporating the circuit board and the flow rate sensor, are fixed in the casing and integrated as one sensor assembly, and the sensor assemblies are attached to mounting holes formed in the housing. By inserting, a part of the outer peripheral surface of the casing of the sensor assembly becomes a part of the wall surface of the bypass channel 11 to form a sub bypass channel, and the wall surface is aligned in the flow direction of the sub bypass channel. In addition, a flow sensor and a plurality of sensors are arranged. In addition, the humidity sensor
Arranged upstream of the flow sensor.
According to the fourth invention of the present application, the intake air temperature sensor is arranged upstream of the flow rate sensor and the humidity sensor .

According to this, since the flow sensor and a plurality of sensors other than the flow sensor are arranged side by side in the same flow path, it is possible to unify the connection mode to the external device, and to handle the wiring. And the assembly process can be simplified.
It is also possible to select and assemble the number and type of a plurality of sensors other than the flow rate sensor for each product without major changes in the structure of the housing and the assembling process.
Furthermore, the humidity sensor and the intake air temperature sensor are arranged upstream of the flow sensor that generates heat in the sub-bypass flow path, so that the humidity sensor and the intake air temperature sensor are not affected by the heat generated by the flow sensor. be able to.

It is a typical sectional view of an air flow measuring device (example). It is a typical sectional view of a sensor assembly (example). It is a typical sectional view of an air flow measuring device (example). It is a typical sectional view of a sensor assembly (example).

  The mode for carrying out the present invention will be described in detail with reference to the following examples.

[Configuration of Example]
The structure of the air flow rate measuring apparatus 1 of an Example is demonstrated using FIGS.
The air flow rate measuring device 1 is, for example, an air flow meter that measures the flow rate of air sucked into an automobile engine, and is attached to a duct D connected to the downstream side of the air cleaner.
The air flow rate measuring device 1 is integrally configured by a housing 2, a flow rate sensor 3, a plurality of sensors 4 to 6 other than the flow rate sensor 3, a circuit module 7, and the like described below.

  The housing 2 is disposed in the duct and bypasses the flow path 10 that takes in part of the air flowing in the main flow path Da formed in the duct D, and flows from the bypass flow path 10 by branching from the bypass flow path 10. A sub-bypass passage 11 for taking in a part of air is formed inside.

  The bypass channel 10 includes a bypass inlet 13 that opens to the mainstream upstream side surface of the housing 2 and a bypass outlet 14 that opens to the mainstream downstream side surface of the housing 2, and extends in the mainstream direction from the bypass inlet 13 toward the bypass outlet 14. A flow path is formed in a straight line (see FIG. 1).

  The sub-bypass channel 11 has a sub-bypass inlet 15 branched from the bypass channel 10 and a sub-bypass outlet 16 that opens toward the mainstream downstream side. Between the sub-bypass inlet 15 and the sub-bypass outlet 16. It is formed in the shape of a channel connected in a U shape.

  Specifically, as shown in FIG. 1, the sub-bypass channel 11 has a first channel 19 that directs the air flowing in from the sub-bypass inlet 15 toward the radially outer side of the mainstream (upward in the height direction, upward in the drawing). Thereafter, the second flow path 20 is directed to the downstream side of the main flow, and then the third flow path 21 is directed to the radially inner side of the main flow (the lower side in the height direction, the lower side in the drawing).

  Since the air taken into the bypass channel 10 passes through the bypass channel 10 in a straight line, the dust in the air travels straight through the bypass channel 10 by inertial force. Therefore, dust is separated at the branch of the bypass flow path 10 and the sub bypass flow path 11, and air from which dust is separated flows from the sub bypass inlet 15.

  The flow sensor 3 is disposed in the sub-bypass flow path 11 and generates a heat transfer phenomenon with the taken-in air, and generates and outputs an electrical signal corresponding to the air flow rate (see FIG. 1). . For example, a heat generating element and a temperature sensitive element formed of a thin film resistor are formed on the surface of a semiconductor substrate, and a circuit board (not shown) built in the circuit module 7 is formed by wiring 3a. Electrically connected.

  The plurality of sensors 4 to 6 other than the flow rate sensor 3 measure various physical quantities of the air flowing inside the duct. In the present embodiment, the plurality of sensors 4 to 6 are the intake air temperature sensor 4, the humidity sensor 5, and the pressure sensor 6. .

The intake air temperature sensor 4 is for detecting the temperature of the air flowing through the main flow path Da, and is electrically connected to a circuit board built in the circuit module 7 by a wiring 4a.
The humidity sensor 5 is for detecting the humidity of the air flowing through the main flow path Da, and is electrically connected to a circuit board built in the circuit module 7 by wiring 5a.
The pressure sensor 6 is for detecting the pressure of the air flowing through the main flow path Da, and is electrically connected to a circuit board built in the circuit module 7 by a wiring 6a.

  The circuit module 7 includes a circuit for controlling energization to the various sensors 3 to 6, a circuit for processing electric signals from the various sensors 3 to 6 and outputting them to an external ECU (electronic control device for engine control). The formed circuit board is built in.

  And the terminal 25 connected to a circuit board protrudes from the circuit module 7, and the terminal 25 is connected to the terminal pin 27 of the connector 26 inside a housing. And the circuit module 7 and ECU are electrically connected through the terminal pin 27 because the connector 26 is connected to the connector on the ECU side.

[Features of Examples]
The characteristics of the air flow rate measuring device 1 of the embodiment will be described.
In the present embodiment, various sensors 3 to 6 are installed in the sub-bypass channel 11 along the flow direction of the sub-bypass channel 11.

For example, in this embodiment, the third flow path 21 extends linearly, and various sensors 3 to 6 are arranged in the third flow path 21 in a line in the flow direction.
And the various sensors 3-6 are arrange | positioned in order of the intake temperature sensor 4, the humidity sensor 5, the flow sensor 3, and the pressure sensor 6 from the upstream.
The various sensors 3 to 6 are installed such that the sensing unit is exposed in the sub-bypass channel 11.

  The circuit module 7 is arranged on the upper side of the row in which the various sensors 3 to 6 are arranged (outside in the duct radial direction), and the wiring for connecting to the circuit module 7 is provided on the upper side in the drawing from each of the various sensors 3 to 6. It extends.

Various sensors 3 to 6 are modularized together with the circuit module 7.
That is, for example, various sensors 3 to 6 and the circuit module 7 are fixed in a resin casing 30 and integrated as one sensor assembly (assembly 31).

The assembly 31 is inserted into the mounting hole 2 a formed in the housing 2, so that various sensors 3 to 6 are installed in the sub-bypass channel 11.
In the present embodiment, a part of the outer peripheral surface of the casing 30 forms a part of the wall surface that forms the sub-bypass channel 11.

[Effects of Example]
According to the air flow rate measuring apparatus 1 of the present embodiment, various sensors 3 to 6 are installed in the sub-bypass channel 11 along the flow direction of the sub-bypass channel 11.
That is, since the various sensors 3 to 6 are arranged side by side in the same flow path, it is possible to make the connection mode to the external device the same mode and simplify the wiring and assembly process. be able to.

For example, as in the embodiment, by arranging the circuit module 7 on one end side of the row in which the various sensors 3 to 6 are arranged, the direction in which the wirings 3 a to 6 a from the various sensors 3 to 6 are extended is unified. Therefore, the connection mode to the circuit module 7 and the connection mode to the external device (ECU) via the circuit module 7 can be unified.
If the connection mode can be unified, the assembly process can be simplified.

The number and types of the plurality of sensors 4 to 6 other than the flow rate sensor 3 can be selected and assembled for each product without significant changes in the structure of the housing 2 or the assembly process.
For example, the pressure sensor 6 may be unnecessary depending on the product among the plurality of sensors 4 to 6 other than the flow rate sensor 3.
In that case, according to the present embodiment, as shown in FIGS. 3 and 4, a variation from which the pressure sensor 6 is removed can be easily manufactured.

  Moreover, since the various sensors 3-6 are arrange | positioned in the sub bypass flow path 11, it is hard to receive to the influence of disturbances, such as a pulsation, and can improve a measurement precision. Moreover, there is little penetration | invasion of dust to the sub bypass flow path 11, and durability of the various sensors 3-6 distribute | arranged in the sub bypass flow path 11 can be improved.

In the present embodiment, the various sensors 3 to 6 are integrated together with the circuit module 7 as one assembly 31.
According to this, various sensors 3 to 6 can be assembled in the sub-bypass flow path 11 by one operation of assembling the assembly 31 to the housing 2. For this reason, the assembly process can be simplified.
The various sensors 3 to 6 may be modularized and connected to the circuit module 7.

In the present embodiment, the intake air temperature sensor 4, the humidity sensor 5, and the flow rate sensor 3 are arranged in the order of the intake air temperature sensor 4, the humidity sensor 5, and the flow rate sensor 3 from the upstream side.
Although the flow rate sensor 3 generates heat by a heat generating element, the intake air temperature sensor 4 can be prevented from being affected by the heat generated by the flow rate sensor 3 by disposing the intake air temperature sensor 4 upstream of the flow rate sensor 3.

Further, the humidity sensor 5 may also generate heat. Thus, by arranging the intake air temperature sensor 4 on the upstream side of the humidity sensor 5, the intake air temperature sensor 4 can be prevented from being affected by the heat generated by the flow rate sensor 3.
Since the heat generation of the flow sensor 3 is larger than the heat generation of the humidity sensor 5, it is preferable to arrange the intake air temperature sensor 4, the humidity sensor 5, and the flow sensor 3 in this order from the upstream side.

DESCRIPTION OF SYMBOLS 1 Air flow measuring device 2 Housing 3 Flow sensor 4 Intake temperature sensor 5 Humidity sensor 6 Pressure sensor 10 Bypass flow path 11 Sub bypass flow path D Duct

Claims (6)

A bypass flow path (10) that takes in a part of the mainstream air flowing inside the duct (D), and one of the air that is branched from the bypass flow path (10) and flows through the bypass flow path (10) A housing (2) formed with a sub-bypass channel (11) for taking in the part,
Depending on the flow rate of air in the duct (D) due to heat generated by the heating element and heat transfer with the air passing through the sub-bypass channel (11). A flow sensor (3) for generating an electrical signal,
And an air flow rate measuring device comprising a plurality of sensors (4-6) other than the flow rate sensor for measuring a physical quantity of air in the duct (D),
The plurality of sensors (4-6) include an intake air temperature sensor (4) for measuring the temperature in the duct (D), a humidity sensor (5) for measuring the humidity in the duct (D), And a pressure sensor (6) for measuring the pressure in the duct (D),
The plurality of sensors (4 to 6), together with the flow rate sensor (3), are modularized with a circuit module (7) containing a circuit board and integrated as a single sensor assembly (31).
The flow sensor (3) and the plurality of sensors (4 to 6) are installed in the sub-bypass channel (11) when the sensor assembly (31) is assembled to the housing (2),
The air flow measuring device, wherein the humidity sensor (5) is arranged upstream of the flow sensor (3). A bypass flow path (10) that takes in a part of the mainstream air flowing inside the duct (D), and one of the air that is branched from the bypass flow path (10) and flows through the bypass flow path (10) A housing (2) formed with a sub-bypass channel (11) for taking in the part,
Depending on the flow rate of air in the duct (D) due to heat generated by the heating element and heat transfer with the air passing through the sub-bypass channel (11). A flow sensor (3) for generating an electrical signal,
And an air flow rate measuring device comprising a plurality of sensors (4-6) other than the flow rate sensor for measuring a physical quantity of air in the duct (D),
The plurality of sensors (4-6) include an intake air temperature sensor (4) for measuring the temperature in the duct (D), a humidity sensor (5) for measuring the humidity in the duct (D), And a pressure sensor (6) for measuring the pressure in the duct (D),
The plurality of sensors (4 to 6), together with the flow rate sensor (3), are modularized with a circuit module (7) containing a circuit board and integrated as a single sensor assembly (31).
The flow sensor (3) and the plurality of sensors (4 to 6) are installed in the sub-bypass channel (11) when the sensor assembly (31) is assembled to the housing (2),
The air flow rate measuring device according to claim 1, wherein the intake air temperature sensor (4) is arranged upstream of the flow rate sensor (3) and the humidity sensor (5) . In the air flow rate measuring device according to claim 1 or 2 ,
The sensor assembly (31) fixes the plurality of sensors (4 to 6) in a casing (30), and a part of the outer peripheral surface of the casing (30) is formed in the sub-bypass channel (11). An air flow rate measuring device characterized in that it forms a part of a wall surface that forms a wall . In the air flow rate measuring device according to any one of claims 1 to 3,
The bypass channel (10) is formed linearly with respect to the mainstream direction,
The sub-bypass channel (11)
A first flow path (19) for directing air flowing in from the inlet (15) of the sub-bypass flow path (11) radially outward with respect to the flow direction of the bypass flow path (10);
A second flow path (20) connected to the first flow path (19) and directing the flow direction of the first flow path (19) toward the downstream side of the main flow;
A third flow path (21) that is connected to the second flow path (20) and directs the flow direction of the second flow path (20) toward the radially inner side of the main flow,
The flow sensor (3) and the plurality of sensors (4 to 6) are installed side by side in the flow direction of the third flow path (21) in the sub bypass flow path (11). An air flow rate measuring device. A bypass flow path (10) that takes in a part of the mainstream air flowing inside the duct (D), and one of the air that is branched from the bypass flow path (10) and flows through the bypass flow path (10) A housing (2) formed with a sub-bypass channel (11) for taking in the part,
Depending on the flow rate of air in the duct (D) due to heat generated by the heating element and heat transfer with the air passing through the sub-bypass channel (11). A flow sensor (3) for generating electrical signals,
And it is a manufacturing method of an air flow measuring device provided with a plurality of sensors (4-6) other than the flow rate sensor for measuring the physical quantity of the air in the duct (D),
The plurality of sensors (4 to 6) include an intake air temperature sensor (4) for measuring the temperature in the duct (D) and a humidity sensor (5) for measuring the humidity in the duct (D). )
The plurality of sensors (4-6), together with the circuit module (7) incorporating the circuit board and the flow rate sensor (3), are fixed in the casing (30) and integrated as one sensor assembly (31). Every
By inserting the sensor assembly (31) into a mounting hole (2a) formed in the housing (2), a part of the outer peripheral surface of the casing (30) of the sensor assembly (31) is allowed to flow into the sub-bypass flow. The flow sensor (3) and the flow sensor (3) are arranged so as to form part of the wall surface of the passage 11 to form the sub-bypass channel (11) and to line up in the flow direction of the sub-bypass channel (11) on the wall surface. Arrange a plurality of sensors (4-6),
A method of manufacturing an air flow rate measuring device, wherein the humidity sensor (5) is arranged upstream of the flow rate sensor (3). A bypass flow path (10) that takes in a part of the mainstream air flowing inside the duct (D), and one of the air that is branched from the bypass flow path (10) and flows through the bypass flow path (10) A housing (2) formed with a sub-bypass channel (11) for taking in the part,
Depending on the flow rate of air in the duct (D) due to heat generated by the heating element and heat transfer with the air passing through the sub-bypass channel (11). A flow sensor (3) for generating an electrical signal,
And it is a manufacturing method of an air flow measuring device provided with a plurality of sensors (4-6) other than the flow rate sensor for measuring the physical quantity of the air in the duct (D),
The plurality of sensors (4 to 6) include an intake air temperature sensor (4) for measuring the temperature in the duct (D) and a humidity sensor (5) for measuring the humidity in the duct (D). )
The plurality of sensors (4-6), together with the circuit module (7) incorporating the circuit board and the flow rate sensor (3), are fixed in the casing (30) and integrated as one sensor assembly (31). Every
By inserting the sensor assembly (31) into a mounting hole (2a) formed in the housing (2), a part of the outer peripheral surface of the casing (30) of the sensor assembly (31) is allowed to flow into the sub-bypass flow. The flow sensor (3) and the flow sensor (3) are arranged so as to form part of the wall surface of the passage 11 to form the sub-bypass channel (11) and to line up in the flow direction of the sub-bypass channel (11) on the wall surface Arrange a plurality of sensors (4-6),
A method of manufacturing an air flow rate measuring device, wherein the intake air temperature sensor (4) is arranged upstream of the flow rate sensor (3) and the humidity sensor (5) .

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