JP2016138745A - Air flow rate measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air flow rate measurement device which achieves improvement in surface accuracy and reduction in size even while having a double bent structure.SOLUTION: A rib (protrusion part) is not provided because it makes miniaturization difficult. An air flow rate measurement device has a double bent structure in which a deep thickness thinning part (recess part) for improving surface accuracy cannot be used, so that a part of a connector terminal 10 is premolded with plastic, and then the premolded connector terminal 10 is formed into a shape of a housing by plastic molding.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a structure of an air flow measuring device for measuring intake air of an automobile engine.

In an automobile engine, it is necessary to measure the intake air flow rate in order to control the fuel injection amount. One type of device for measuring the intake air flow rate is a heating resistor type air flow rate measurement device.
The air flow rate measuring device inserts the sensor portion of the air flow rate measuring device from the insertion hole provided in the intake pipe, is fixed to the outer wall of the intake pipe by the flange portion, and transmits the flow rate measured by the sensor portion from the connector portion as an electrical signal. The method is used. The connector portion has a first connection portion that is electrically connected to the circuit element on one end side and a second connection portion that is electrically connected to the outside on the other end side. The shape of the connector part includes a straight connector structure horizontal to the insertion direction, a single vent structure perpendicular to the fluid flow and the insertion direction, and a double vent structure parallel to the fluid flow and perpendicular to the insertion direction. is there. In addition, the outer surface of the flow rate measuring device is mainly constituted by a plastic mold.

  When inserting this flow measuring device, use a packing to prevent the gas from leaking from the insertion part when a large warp deformation occurs on the plastic flange surface that contacts the outside of the sealed space. It becomes difficult to seal. Therefore, although the accuracy improvement of the flatness of the flange surface is a big problem, as shown in Patent Document 1, the surface to improve the airtightness as a structure for improving the dimensional accuracy of the plastic surface and improving the airtightness. Among them, the contact area is reduced, and only the contact surface is improved in flatness accuracy. Furthermore, there is an example in which the surface accuracy is improved by providing a rib in order to improve the surface accuracy.

Patent 3689630

  In recent years, fuel efficiency and safety have been emphasized, and parts in the engine room have been further increased by reducing the size for improving fuel efficiency and installing pedestrian protection airbags in the engine room to improve safety. Miniaturization is necessary. When surface accuracy is improved and miniaturization is performed with a double vent structure, the connector terminal is distributed in a complicated manner, so the connector terminal contacts and deforms due to the molding pressure during plastic molding. However, there is a problem that it is difficult to reduce the size because it is necessary to increase the distance between the terminals. Moreover, if a rib (convex part) is provided, size reduction becomes difficult. Surface accuracy can be improved by providing meat stealing (recesses), but the double vent structure makes it difficult to distribute and makes it difficult to deepen meat stealing (recesses). There is a problem that it is not possible.

  In order to solve the above problems, in the present invention, a part of the connector terminal is pre-molded with plastic. Thereafter, the pre-molded connector terminal is molded with plastic to obtain a final housing shape.

  By performing the pre-molding, it is possible to prevent the connector terminal from being deformed or violated at the time of forming the connector portion, so that the connector terminal can be thinned, and as a result, the distance between the terminals can be narrowed. Furthermore, since the thickness of the plastic on the surface whose surface accuracy is to be improved can be reduced, warping deformation when cooled after molding can be reduced. According to the present invention, even with a double vent structure, the surface accuracy of the flange surface can be ensured and the size can be reduced.

Installation diagram of air flow measurement device on the body AA sectional view of FIG. Schematic side view showing an embodiment of the present invention Schematic diagram of the upper surface showing an embodiment of the present invention Schematic diagram of the upper surface showing an embodiment of the present invention Schematic diagram of the upper surface showing an embodiment of the present invention Schematic diagram of the upper surface showing an embodiment of the present invention Schematic side view showing an embodiment of the present invention Schematic side view showing an embodiment of the present invention

  Embodiments of an air flow measuring device according to the present invention will be described below with reference to the drawings.

    A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic cross-sectional view of a state in which an air flow rate measuring device 2 according to a first embodiment of the present invention is mounted on a body 3 that forms an intake passage, and FIG. 2 is an air diagram according to the first embodiment. 3 is a diagram showing a schematic configuration of an air temperature detection element 1 and an air flow rate detection element 4 of the flow rate measuring device 2. FIG. 3 and 4 are diagrams showing a schematic configuration of a pre-mold shape inserted in the air flow measuring device 2 according to the first embodiment.

  In FIG. 1, an air flow rate measuring device 2 is attached to a body 3 and exposed to intake fluid flowing in an intake passage. The air temperature detection element 1 is provided on the upstream side of the air flow rate measuring device 2 to be exposed to the intake fluid, and the air flow rate detection element 4 is provided in the auxiliary passage 7. Here, the chip package 5 which is a mold structure including the air flow rate detecting element 4, the integrated circuit 11, and the air temperature detecting element is formed. Then, the air flow rate detecting element 4 is exposed to the sub-passage 7 by insert molding the chip package 5 when forming the housing. The signals of the air flow rate detecting element 4 and the air temperature detecting element 1 are taken into the integrated circuit 11, corrected, and then transmitted to the outside through the lead frame 12 and the connector terminal 10 connected to the lead frame 12. The connector terminal 10 is composed of a plurality of plate conductors.

  As shown in FIGS. 3 and 4, the connector terminal 10 is bent once in a direction perpendicular to the flow of the intake passage and then in a plane parallel to the bent direction (flange parallel plane). A double vent structure that is bent at least once in a direction different from the direction perpendicular to the flow of the intake passage. A part of the connector terminal 10 is molded with a resin having a thickness of 0.5 mm or more so as to include the bent portion, whereby the pre-molded portion 9 is formed. After the pre-mold portion 9 is formed, the pre-mold 9 is insert-molded with a resin that forms the housing.

  The connector terminal 10 cannot be configured to be exposed except for a harness connecting portion that is connected to the harness and an integrated circuit connecting portion that is electrically connected to the integrated circuit 11 mounted inside the housing. When inserting the connector terminal, it is necessary to grip and insert only the harness connection portion and the integrated circuit connection portion. Therefore, when a complicated shape having a plurality of bends between the harness connection part and the integrated circuit connection part is inserted into the housing, such as a double vent structure, the connector terminal may be violated by the molding pressure when forming the housing. There is a problem that the bent portion is easy to come into contact. However, when the premold portion 9 is formed as in the present embodiment, at the time of the formation of the premold portion 9, it is possible to mold by gripping a portion from the bent portion rather than the harness connection portion or the integrated circuit connection portion. Therefore, the ramp of the connector terminal 10 can be reduced, and at the time of molding the housing, the connector terminal 10 is fixed by the pre-molded portion 9, so that each plate-like conductor of the connector terminal 10 is formed by molding pressure when molding the housing. Since it does not contact and the bent part is prevented from being deformed, it can be stably molded. Furthermore, since it can shape | mold without separating the space | interval between each plate-shaped conductor in the connector terminal 10, and without making the plate-shaped conductor which forms the connector terminal 10 thick, size reduction in a double vent structure is attained. In the present embodiment, an example in which the housing and the connector are integrally formed has been shown, but separate configurations may be employed. In that case, after forming the above-mentioned pre-molded body, this pre-molded body is insert-molded into a resin forming the connector.

    Next, Example 2 will be described with reference to FIG. The description of the same configuration as that of the first embodiment is omitted.

    The premold portion 9 has an exposed portion 14 from which a part of the connector terminal 10 is exposed. The exposed portion 14 has a groove shape that exposes the flange side of the pre-molded portion 9 or the opposite surface, and a through-hole shape that exposes both sides. The exposed portion 14 is covered with resin when the housing is formed. The exposed portion 14 is a bent portion of the connector terminal or in the vicinity of the bent portion of the connector terminal 10 and is in a direction perpendicular to the extending direction of the connector terminal 10. It is good to form so that it may be exposed.

  According to this embodiment, the connector terminal 10 is fixed with a mold in order to form the exposed portion 14. Therefore, it becomes possible to form more fixing portions of the connector terminal 10 when forming the pre-molded portion 9, and further, it becomes possible to fix the bent portion directly or in the vicinity of the bent portion with a mold, depending on the molding pressure. The play of the connector terminal 10 can be suppressed more effectively. Furthermore, the occurrence of voids at the time of housing molding can be reduced by suppressing the blowout of the connector terminal 10.

  Next, Example 3 will be described with reference to FIGS. In the third embodiment, in addition to the configuration of each of the embodiments described above, a premold through hole 13 is formed in a part of the premold portion 9 so that the connector terminal 10 is not exposed.

  According to the present embodiment, the stress due to the molding pressure when the premold 9 is covered with the resin forming the air flow measuring device 2 can be reduced by the premold through hole 13. Therefore, when the configuration of the third embodiment is applied to each of the above-described embodiments, the residual stress at the time of housing molding can be further reduced.

  As a modification of the pre-mold through-hole 13, the same effect can be obtained even if the groove shape does not penetrate. In the case of the groove shape, similar to the exposed portion of Example 2, if it is formed in the vicinity of the bent portion of the connector terminal 10 and perpendicular to the extending direction of the connector terminal 10, the residual stress in the vicinity of the bent portion is formed. Therefore, the connector terminal 10 can be reduced in size, which is more desirable.

    Next, Example 4 will be described with reference to FIGS. In the fourth embodiment, in addition to the configuration of each of the embodiments described above, the bush 15 is also configured in the premold portion 9 simultaneously with the premolding.

  According to the fourth embodiment, since the bush 15 is covered with the resin at the same time as the connector terminal 10, the pre-molded portion 9 can be enlarged. Therefore, when the configuration of the fourth embodiment is applied to each of the above-described embodiments, the warp deformation of the plastic flange surface where the air flow rate measuring device 2 is in contact with the intake pipe outer wall can be further reduced.

    Next, Example 5 will be described with reference to FIG. Example 7 is an example in which the configurations of Examples 2 to 4 are combined. The effects of the above-described embodiments are provided.

    Next, Example 6 will be described with reference to FIGS. The difference from the above-described embodiments is that the housing has a pre-mold exposed portion 16 in which the pre-mold portion 9 is exposed from the housing resin.

  According to the sixth embodiment, since the premold portion 9 is partially exposed from the housing, the premold 9 can be fixed with a mold when the air flow rate measuring device 2 is molded. When the pre-molded connector terminal 10 is insert-molded into the housing, not only the harness connection part and the integrated circuit connection part but also the pre-mold part 9 can be fixed. Variations due to molding pressure can be suppressed. Therefore, when the configuration of the sixth embodiment is applied to each of the above-described embodiments, the cross-sectional area of the plate-like conductor can be further reduced, and the effect of enabling further miniaturization can be obtained.

DESCRIPTION OF SYMBOLS 1 ... Air temperature detection element, 2 ... Air flow measuring device, 3 ... Body, 4 ... Air flow detection element, 5 ... Chip package, 6 ... Main passage, 7 ... Sub passage, 8 ... Air flow, 9 ... Pre-mold 10, connector terminal 11, integrated circuit, 12 lead frame, 13 pre-mold through-hole, 14 exposed portion, 15 bush, 16 pre-mold exposed portion

Claims (9)

In the air flow measuring device with double vent structure,
A first resin portion covering the bent portion of the connector terminal;
An air flow rate measuring device comprising: a second resin portion that covers the first resin portion.   The air flow rate measuring device according to claim 1, wherein the connector terminal has an exposed portion exposed from the first resin portion in the vicinity of the bent portion and / or the bent portion.   The air flow rate measuring device according to claim 1, wherein the first resin portion is formed so as to expose the bent portion and / or the bent portion.   The air flow rate measuring device according to claim 3, wherein the first resin portion is formed so as to expose each conductor of the connector terminal.   The air flow rate measuring device according to any one of claims 1 to 4, wherein the first resin portion is formed with a groove.   The air flow rate measuring device according to any one of claims 1 to 5, wherein the first resin part has an exposed part exposed from the second resin part.   6. The air flow rate measuring device according to claim 1, wherein the first resin has a protruding portion, and the second resin is formed such that a tip portion of the protruding portion is exposed. Has a bush,
The air flow measuring device according to any one of claims 1 to 7, wherein the bush is inserted into the first resin portion. Bending process for bending the connector terminal in multiple directions;
A pre-molding step of forming a pre-molded body by injecting a first resin into the mold, so as to suppress the bent portion of the connector terminal and / or the vicinity of the bent portion;
The pre-mold body is placed in a second mold, and a second resin is injected to form a housing, and at the same time, an insert mold step for inserting the pre-mold body into the housing is manufactured. Method.