JP2014016188A - Air flow rate measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with, regarding an air flow rate measuring apparatus to which a temperature sensor is attached, resin molding of a terminal assy.SOLUTION: A through hole 6 is bored in a case 4, and a lead 23 of a temperature sensor is passed through the through hole 6, which is filled with adhesive. The tip of the lead 23 having passed the through hole 6 is conductively joined to a terminal. In this way, even if no terminal assy is provided, the position of the terminal can be stabilized when the lead 23 and the terminal are conductively joined, and furthermore the through hole 6 can be blocked at the time of molding the housing. In this way, molding of the terminal assy can be dispensed with.

Description

  The present invention relates to an air flow rate measuring device that measures the flow rate of air flowing through a predetermined passage.

  2. Description of the Related Art Conventionally, for example, in a thermal air flow measurement device that measures the flow rate of intake air sucked into an internal combustion engine (hereinafter sometimes referred to as intake air amount), the intake air is contained in a housing containing a flow sensor. It is well known that a temperature sensor for measuring temperature (hereinafter sometimes referred to as intake air temperature) is attached. A signal (a signal indicating the intake air temperature) generated by the temperature sensor is output from the air flow measurement device together with a signal indicating the intake air amount to, for example, an electronic control unit (hereinafter referred to as an ECU) that controls the internal combustion engine. It is used for temperature compensation for appropriately controlling the intake system of the internal combustion engine (see, for example, Patent Document 1).

  By the way, according to the conventional air flow measuring device 100 shown in FIG. 10, it is necessary to stabilize the position of the terminal 103 when the lead wire 102 of the temperature sensor 101 is conductively joined to the terminal 103. In addition, in order to allow the temperature sensor 101 to protrude into the passage while the O-ring 105 is attached to the housing 104 and sealed in the passage, the housing 104 is provided with a hole 107 having a size through which the temperature sensor 101 can pass. Therefore, it is necessary to seal the hole 107 when the housing 108 is resin-molded. Therefore, according to the air flow rate measuring apparatus 100, in order to stabilize the position of the terminal 103 and seal the hole 107, the terminal assembly 109 is provided by resin molding using the terminal 103 as an insert.

  However, according to the air flow measuring device 100, in addition to the resin molding of the terminal assembly 109, the resin molding of the sensor assembly 111 including the flow sensor 110, the casing 104, the terminal assembly 109, the sensor assembly 111, and the like are used as inserts. It is necessary to perform resin molding of the housing 108. For this reason, since there are many resin moldings with insert products and the process is complicated, a structure that can omit the resin molding of the terminal assembly 109 is required.

JP 2010-181354 A

  The present invention has been made to solve the above-described problems, and an object of the present invention is to eliminate the resin molding of the terminal assembly with respect to an air flow rate measuring apparatus provided with a temperature sensor.

According to the present invention, the air flow rate measuring device includes the following casing, temperature sensor, through hole, and terminal.
First, the housing has a bypass flow path that takes in a part of the air flowing through a predetermined passage and accommodates the thermal flow sensor in the bypass flow path. The temperature sensor has a temperature detection element that is exposed to air flowing through a predetermined passage, and a lead wire extending from the temperature detection element. Further, the through hole is provided in the housing, and the lead wire is passed therethrough and filled with an adhesive. Furthermore, the terminal is conductively joined to the tip of the lead wire that has passed through the through hole.

  As a result, the tip of the lead wire protrudes from the through hole in a region opposite to the passage and is conductively joined to the terminal, thereby eliminating the need for the terminal to protrude into the passage. For this reason, since the length of the terminal can be shortened, even if the terminal is not resin-molded, for example, by providing a groove or the like in the housing and holding the terminal, the terminal can be The position can be kept stable.

Further, since the through hole can be provided with a small diameter that allows the lead wire to pass therethrough, the through hole can be closed by filling the through hole with an adhesive.
As described above, regarding the air flow rate measuring device to which the temperature sensor is attached, it is possible to stabilize the position of the terminal at the time of conducting joining with the lead wire without providing the terminal assembly, and to form the through hole at the time of resin molding of the housing. Since it can be closed, resin molding of the terminal assembly can be omitted.

It is sectional drawing which shows the inside of an air flow measuring device (Example). It is a side view of an air flow rate measuring apparatus (Example). It is a rear view of an air flow measuring device (example). It is a disassembled perspective view of an air flow measuring device (Example). It is a top view which shows the state before housing shaping | molding (Example). It is a side view which shows the state before housing shaping | molding (Example). It is a rear view which shows the state before housing shaping | molding (Example). It is VI-VI sectional drawing of FIG. 6 (Example). It is a top view which shows the positional relationship of a through-hole and a guide groove (Example). It is a disassembled perspective view of an air flow measuring device (conventional example).

  The air flow rate measuring apparatus of the embodiment will be described based on examples.

[Configuration of Example]
The structure of the air flow rate measuring apparatus 1 of an Example is demonstrated based on FIGS.
The air flow rate measuring device 1 includes a thermal type flow sensor 2, and is disposed in an intake path 3 to an internal combustion engine (not shown), for example, and measures the flow rate (intake amount) of intake air taken into the internal combustion engine. taking measurement. In addition, a temperature sensor 5 for measuring the temperature of intake air (intake air temperature) is attached to the housing 4 in which the flow sensor 2 is built. And the signal (signal which shows intake air temperature) which generate | occur | produced in the temperature sensor 5 is sent from the air flow measuring device 1 to the electronic control unit (ECU: not shown) which controls an internal combustion engine with the signal which shows intake air amount. It is output and used for temperature compensation for appropriately controlling the intake system of the internal combustion engine.

The air flow rate measuring device 1 includes a housing 4, a temperature sensor 5, a through hole 6 and a terminal 7 as described below.
First, the housing 4 includes the flow rate sensor 2 and has a bypass forming portion 10 that protrudes into the intake passage 3 and takes in a part of intake air flowing through the intake passage 3 to flow. And the bypass formation part 10 has the bypass flow path 11 through which the taken in intake air flows, and accommodates the flow rate sensor 2 in the bypass flow path 11.

  Here, the bypass passage 11 has an intake air intake port 12 that opens toward the upstream side of the intake passage 3 and an intake air discharge port 13 that opens toward the downstream side of the intake passage 3. For example, the intake air taken in from the take-in port 12 is circulated and directed toward the discharge port 13. In addition, a dust discharge path 14 for discharging dust is connected to the bypass flow path 11 on the upstream side of the flow sensor 2, and the dust that has entered the bypass flow path 11 is not directed to the flow sensor 2. It returns to the intake passage 3 through the discharge passage 14. The bypass flow path 11 is branched into two on the downstream side of the flow sensor 2, and two discharge ports 13 are provided.

  Further, the flow rate sensor 2 projects into a region of the bypass flow path 11 where, for example, intake air flows in a direction opposite to the flow in the intake passage 3. The flow sensor 2 is resin-molded as an insert product together with a processing unit (not shown) that performs a predetermined process on the generated signal and another terminal 15 that conducts the terminal 7 and the processing unit. 16 (see FIG. 4 etc.). The sensor assembly 16 is pressed and held in, for example, the housing 4 so that the flow sensor 2 protrudes into the bypass flow path 11.

  Moreover, the housing | casing 4 has the sealing part 19 which blocks the insertion hole 18 for inserting the bypass formation part 10 in the intake passage 3, and making it protrude. The sealing portion 19 is provided in a slightly thick disc shape, and an O-ring 20 is mounted in a circumferential groove, and the O-ring 20 ensures airtightness in the insertion hole 18. The blocking portion 19 is unevenly distributed at one end of the bypass forming portion 10 so as to be unevenly distributed on the inner wall side of the intake passage 3 when the bypass forming portion 10 is protruded into the intake passage 3.

  The temperature sensor 5 includes a temperature detection element 22 that is exposed to intake air flowing through the intake passage 3, and a lead wire 23 that extends from the temperature detection element 22. Note that the temperature detection element 22 is, for example, a known thermistor, and is separated from the bypass formation unit 10 to such an extent that it is not thermally affected by the bypass formation unit 10.

  The through-hole 6 is provided so as to linearly penetrate the blocking portion 19 in the thickness direction, and the opening 6a is formed on each of the side where the bypass forming portion 10 exists and the side where the bypass forming portion 10 does not exist. 6b (see FIG. 8 etc.). And the front-end | tip part of the lead wire 23 is inserted in the through-hole 6 from the opening 6a, and protrudes from the opening 6b. Further, the through hole 6 is filled with an adhesive with the lead wire 23 passing therethrough. The opening 6b is provided at the bottom of the hole 24 for dropping the adhesive.

  The bypass forming portion 10 is provided with a guide portion 26 that guides the lead wire 23 when the lead wire 23 is passed through the through hole 6. Here, the guide portion 26 is provided so as to protrude from the bypass forming portion 10, and a linear guide groove 27 is provided on the raised top plane (see FIGS. 4 and 6). The guide groove 27 is provided so as to have a V-shaped cross section, and the bottom of the guide groove 27 is connected to the through hole 6 through the opening 6a so as to be coaxial with the through hole 6 (see FIG. 8 and FIG. 8). (See FIG. 9 etc.)

And the bottom of the guide groove 27 exists in the inner peripheral side rather than the periphery of the opening 6a (refer FIG.8, FIG9 etc.).
Further, a press-fitting recess 28 into which the lead wire 23 is press-fitted is provided at the opposite end of the guide groove 27 to the end connected to the through hole 6 (see FIGS. 2 and 6). .

  The terminal 7 is conductively joined to the tip of the lead wire 23 protruding from the opening 6b and the tip of the terminal 15 protruding from the sensor assembly 16 (see FIGS. 4 to 7 and the like). Further, the terminal 7 is conductively joined to the distal end portion of the lead wire 23 and the distal end portion of the terminal 15 in a state where the terminal 7 is fitted and held in the concave portion 29 provided in the sealing portion 19 (see FIGS. 4 to 7 and the like). .)

  The terminal 7 is resin-molded as an insert product together with the housing 4 and the sensor assembly 16, and constitutes a connector 30 for outputting signals indicating the intake air amount and the intake air temperature to the ECU (hereinafter, the terminal 7, the housing 4). The resin portion formed by resin molding using the sensor assembly 16 as an insert product is called a housing 31. The housing 31 includes the resin portion of the connector 30.)

[Effects of Examples]
According to the air flow measuring device 1 of the embodiment, the through hole 6 is provided in the housing 4, and the lead wire 23 of the temperature sensor 5 is passed through the through hole 6 and the adhesive is filled. The leading end of the lead wire 23 that has passed through the through hole 6 is conductively joined to the terminal 7 that constitutes the connector 30.

  As a result, the leading end portion of the lead wire 23 protrudes from the through hole 6 in a region opposite to the intake passage 3 across the blocking portion 19 and is electrically connected to the terminal 7, so that the terminal 7 protrudes into the intake passage 3. The need to let go. For this reason, since the length of the terminal 7 can be shortened, even if the terminal 7 is not resin-molded, for example, by forming the recess 29 in the housing 4 and holding the terminal 7, The position of the terminal 7 can be stabilized at the time of conducting joining.

Further, since the through hole 6 can be provided with a small diameter that allows the lead wire 23 to pass therethrough, the through hole 6 can be closed by filling the through hole 6 with an adhesive.
As described above, regarding the air flow rate measuring apparatus 1 to which the temperature sensor 5 is attached, the position of the terminal 7 can be stabilized at the time of conducting joining with the lead wire 23 without providing a terminal assembly, and the housing 31 is molded. Sometimes the through-hole 6 can be closed. For this reason, the molding of the terminal assembly can be omitted.

Further, the material cost can be reduced by shortening the length of the terminal 7.
Further, the terminal 7 exists in a region on the opposite side of the intake passage 3 across the blocking portion 19, and is electrically connected to the tip portion of the lead wire 23 in a region on the opposite side of the intake passage 3. For this reason, since the terminal 7 is not exposed to the intake passage 3, it is possible to mitigate the thermal influence of the intake air on the temperature detection element 22 through the metal portion. Moreover, since the conduction | electrical_connection junction of the lead wire 23 and the terminal 7 is not exposed to the intake passage 3, the possibility of corrosion of a conduction | electrical_connection junction can be reduced.

The housing 4 has a guide groove 27 that guides the lead wire 23 when the lead wire 23 is passed through the through hole 6, and the guide groove 27 is connected to the through hole 6.
Thereby, since the lead wire 23 can be inserted into the through hole 6 along the guide groove 27, the operation of passing the lead wire 23 through the through hole 6 can be stabilized.

Further, since the bottom of the guide groove 27 exists on the inner peripheral side with respect to the peripheral edge of the opening 6 a, no catch occurs when the lead wire 23 is inserted into the through hole 6.
Further, a press-fit recess 28 into which the lead wire 23 is press-fitted is provided at the end opposite to the connection end with the through-hole 6 in both ends of the guide groove 27, so that the position of the lead wire 23 is stabilized. be able to.

  In addition, the aspect of the air flow rate measuring device 1 is not limited to the embodiment, and various modifications can be considered. For example, the air flow rate measuring device 1 is used for measuring the amount of intake air taken into the internal combustion engine of the vehicle. Besides, it can be applied to various uses.

DESCRIPTION OF SYMBOLS 1 Air flow measuring device 2 Flow sensor 3 Intake passage (predetermined passage) 4 Case 5 Temperature sensor 6 Through-hole 7 Terminal 11 Bypass passage 22 Temperature detection element 23 Lead wire

Claims (4)

A casing (4) having a bypass flow path (11) that takes in a part of the air flowing through the predetermined passage (3) and flows it, and that stores the thermal flow sensor (2) in the bypass flow path (11) When,
A temperature sensor (22) exposed to the air flowing through the predetermined passage (3), and a temperature sensor (5) having a lead wire (23) extending from the temperature sensor (22);
A through hole (6) provided in the housing (4), through which the lead wire (23) is passed and filled with an adhesive;
An air flow rate measuring device (1) comprising a terminal (7) connected to the tip of the lead wire (23) passing through the through hole (6). In the air flow measuring device (1) according to claim 1,
The housing (4) has a groove (27) connected to the through hole (6),
The groove (27) guides the lead wire (23) when the lead wire (23) is passed through the through hole (6). In the air flow measuring device (1) according to claim 2,
The bottom of the groove (27) is present on the inner peripheral side of the inner peripheral surface forming the through hole (6) at the connection position with the through hole (6). (1). In the air flow rate measuring device (1) according to claim 2 or 3,
Of the both ends of the groove (27), a press-fitting recess (28) into which the lead wire (23) is press-fitted is provided at the end opposite to the connection end with the through hole (6). An air flow rate measuring device (1).

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