JP2000265872A - Heating resistor type air flow measurement device - Google Patents

Abstract

(57) [Summary] A gap formed at an interface between a metal base member and a housing mold material may cause outflow or intrusion of a liquid such as silicone gel, and in the worst case, hinder the life of a product. An adhesive or the like is applied to the entire periphery of an interface serving as an outflow passage between a metal base member and the outside of a housing mold material. ADVANTAGE OF THE INVENTION According to this invention, outflow and infiltration of liquids, such as a silicone gel, can be prevented and there exists an effect which prolongs product life.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating resistor type air flow meter provided in a flow path, and more particularly to a heating resistor type air flow measurement device suitable for measuring an air flow rate of an internal combustion engine.

[0002]

2. Description of the Related Art In a conventional heating resistor type air flow measuring device, a base member for mounting and fixing an electric circuit and a support pin for holding the heating resistor and the temperature sensing resistor are integrally formed by a molding material. After the injection of the silicone gel for preventing corrosion of the housing member, the upper surface of the housing member is closed with a cover. A metal collar member to be attached to the intake pipe is insert-molded in the housing member, and has a structure in which it is fastened together with a mounting hole also provided in the base member by a screw or the like.

On the other hand, Japanese Patent Application No. 9-260366 has a structure in which the base member and the housing member are integrally formed in order to shorten the bonding process between the base member and the housing member and to reduce the cost. Accordingly, by providing the mounting hole for mounting in the intake pipe only in the base member, it is possible to improve the mounting accuracy, thereby suppressing the variation in the output characteristics and improving the output characteristics accuracy. However, since the base member employs a single metal plate and the housing member employs a molding material, there is a possibility that a gap may occur at the interface between the base member and the molding member.

[0004]

The gap may cause outflow of the silicone gel or intrusion of the liquid, which in the worst case may hinder the life of the product.

[0005]

As a means for solving the above problem, an adhesive or the like is applied to the entire periphery of the interface between the base member and the housing member to block the outflow path from the gap to the outside, so that the silicone gel is removed. It is possible to prevent outflow and liquid intrusion.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 3 taking a heating resistor type air flow measuring device as an example.

FIG. 1 is a heating resistor type air flow measuring device showing an embodiment of the present invention. FIG. 2 is a sectional view of FIG.
It is a part enlarged view.

The intake air is supplied to the engine through a main air passage 2 and a sub air passage 3 formed in a main air passage constituting member 1. A heating resistor 4 and a temperature-sensitive resistor 5 for measuring an air flow rate are installed in the sub air passage 3.
The temperature-sensitive resistor 5 is electrically connected to the support pin 6 and connected to the electronic circuit 8 via a lead wire. Electronic circuit 8
Is a base member 7 having a mounting hole for mounting to the main air passage component 1, a housing member 9 having an indicator pin 6 and a connector for an interface, and aluminum exposed inside a case set formed by integral molding. The base 7 is mounted and protected by the adhesive 10. Further, the silicone gel 11 is injected into the case set and hardened, and the upper surface of the case is protected by the cover 12. The electronic circuit 8 is configured to output a signal related to the air flow rate based on output signals of the heating resistor 4 and the temperature-sensitive resistor 5.

The base member 7 is a main air passage member 1.
Since the housing member 9 is exposed inside the case set of the mounting hole for mounting the electronic circuit and the electronic circuit mounting portion, a gap 15 is formed at the interface with the housing member 9.
5, there is a possibility that the silicone gel 11 flows out and liquid enters.

In this embodiment, an adhesive 14 is applied to the entire periphery of the interface in order to block the gap 15 generated at the interface from the outside, thereby preventing the silicone gel 11 from flowing out and preventing liquid from entering from the outside. Is being planned. Further, the adhesive 14 enables simultaneous operation with the adhesive 10 used when the adhesive 14 is mounted on the base member 7 of the electronic circuit 8, thereby reducing the number of steps.

[0011]

According to the present invention, the heating resistor type air flow measuring device has an effect of preventing outflow of silicone gel and intrusion of liquid.

[Brief description of the drawings]

FIG. 1 is an air flow measuring device showing one embodiment of the present invention.

FIG. 2 is a sectional view of FIG.

FIG. 3 is an enlarged detail view of FIG. 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main air path constituent member, 2 ... Main air path, 3 ... Sub air path, 4 ... Heating resistor, 5 ... Temperature sensitive resistor, 6 ... Support pin, 7 ... Base member, 8 ... Electronic circuit, 9 ... Housing member, 10: adhesive, 11: silicone gel, 12: cover, 13: mounting hole, 14: adhesive, 15: gap.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Chihiro Kobayashi 2520 Odaiba, Hitachinaka-shi, Ibaraki F-term in the Automotive Equipment Division of Hitachi, Ltd. (Reference) 2F035 AA02 EA03 EA04

Claims (2)

[Claims] 1. A heating resistor and a temperature-sensitive resistor disposed in a gas passage of an internal combustion engine used for an automobile, and a flow rate related to an air flow rate based on output signals of the heating resistor and the temperature-sensitive resistor. An electronic circuit for outputting an output signal, a supporting pin for holding the heating resistor and the temperature-sensitive resistor and electrically connected to the electric circuit, further comprising an attachment hole that can be attached to the gas passage component. It is mounted on a base member, and the base member is formed by integral molding with a housing formed of a resin material forming a connector for an external interface, and further, silicone gel is injected and cured in the housing to protect an electronic circuit. In addition, in the heating resistor type air flow measuring device having a structure to cover and cover the upper surface of the housing, a gap between an interface of the base member and the housing member is silly. Heating resistor type air flow rate measuring apparatus characterized by filling the like over down adhesive. 2. A heating resistor type air flow measuring device according to claim 1, wherein the adhesive or the like applied to the interface between the base member and the housing member can be simultaneously worked with the electronic circuit bonding.