JPH10318239A - Mounting structure of package made of resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability by modifying mounting structure such that stable screw lock fixing of an electronic part used under sever peripheral environment is executed for a long period. SOLUTION: Regarding an electronic part, such as a pressure sensor, a screw hole 1b in which a reinforcing bush 6 made of a metal is inserted is formed in the mounting seat 1a of a resin case 1 consisting of a resin molded product and a fastening screw 4 is inserted in the screw hole and securely screwed at a fixing part 5 on the mating side. In a so formed mounting structure, the height A of a reinforcing bush is set to a value higher than the screw hole depth B of a mounting seat, and in a position where insertion into a mounting seat is effected, the two end faces of the reinforcing bush are vertically protruded from the seat surface of the mounting seat. This constitution prevents the fastening force of a screw from being exerted directly on a mounting seat being a resin molded product, and maintains a stable fixed state for a long period by preventing loosening of a fastening screw due to mechanical deterioration of resin itself.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure of a resin package suitable for an electronic component such as a pressure sensor mounted and used in a severe environment such as an engine room of an automobile.

[0002]

2. Description of the Related Art As is well known, various electronic components such as a pressure sensor are incorporated in an engine room of an automobile.
As a mounting means, the resin case of the electronic component is fixed using small screws or the like. Next, FIGS. 3 and 4 show a conventional mounting structure of a resin package, taking a pressure sensor mounted on an automobile engine as an example. In FIG. 3, 1 is a resin case of a pressure sensor made as a resin molded product, 2 is an external connection terminal, 3 is a pressure guiding pipe, and a screw hole 1b is provided in a mounting seat 1a protruding laterally from the resin case 1. The fastening screw 4 is inserted into the screw hole 1b, and is screwed and fixed to a fixing portion (an engine body of an automobile) 5 on the other side.

Here, in a conventional product, as shown in FIG. 4, a metal reinforcing bush 6 is inserted into a screw hole 1b and is integrally formed with the resin case 1. The reinforcing bush 6 receives the tightening force applied at the time of screw fastening by the bush, and serves to prevent the tightening stress from being applied to the mounting seat 1a, which is a resin molded product. Dimension A is matched with screw hole depth B of mounting seat 1b, and the end face of reinforcing bush 6 is
It is made to be flush with the seat surface of b.

[0004]

The conventional mounting structure constructed as described above has the following problems. That is, when the reinforcing bush 6 is insert-molded into the resin case 1, the reinforcing bush 6 is inserted into a molding die of the resin case, and then a molding resin is injected into the mold to be integrally molded. In this case, the position of the reinforcing bush 6 inserted into the screw hole 1b of the mounting seat 1a may exactly coincide with the end face of the mounting seat 1a as shown in FIG. In many cases, the reinforcing bush 6 is retracted inward from the seat surface of the mounting seat 1a as shown in FIG.

When such a product is screwed to a fixed portion (for example, an engine body of an automobile) of the mating side of the product, the screw head 4a of the fastening screw 4 is attached to the mounting seat 1a as shown in the figure.
(The edge of the screw hole 1b), and the tightening stress of the screw is directly applied to the mounting seat 1a which is a resin molded product. In addition, when exposed to severe environmental conditions (temperature, humidity, mechanical vibrations, etc. of an automobile engine room) for a long period of time in the mounted state where the tightening stress is applied, the resin itself also deteriorates. As a result, cracks and cracks may occur in the mounting seat 1a and loosening of the screw may occur, which may lead to a serious trouble that the electronic component may fall off unexpectedly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to solve the above-mentioned problems and to improve the electronic components so that they can be screwed and fixed stably for a long period of time even in a severe use environment. It is an object of the present invention to provide a resin package mounting structure with improved reliability.

[0007]

According to the present invention, a screw hole having a metal reinforcing bush inserted therein is provided in a mounting seat of a resin case as a resin molded product. The height of the reinforcing bush is set to be larger than the screw hole depth of the mounting seat, and the reinforcing bush is inserted into the mounting seat. The end surface is configured to protrude from the seat surface of the mounting seat. (Claim 1) As an application example of the above configuration, there is a configuration in which a recess is formed in an end surface of a mounting seat of a resin case so as to surround a screw hole and into which a screw head of a fastening screw enters. (Claim 2) According to the above configuration, when the resin case is screwed and fixed, all the tightening force of the fastening screw is applied to the reinforcing bush, and no tightening stress is directly applied to the mounting seat which is a resin molded product. . As a result, even if the product is exposed to severe environmental changes in the actual use state, the fastening screw can be prevented from loosening due to mechanical deterioration of the mounting seat, and a stable fixed state can be maintained for a long time.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to the drawings. In the drawings of each embodiment, the same members corresponding to FIG. 4 are denoted by the same reference numerals. [Embodiment 1] In FIG. 1, a mounting seat 1a of a resin case 1 is shown.
Metal reinforcing bush 6 inserted in screw hole 1b
Means that the height dimension A is the screw hole 1b
The hole depth B is set to be larger than the hole depth B, and both end surfaces of the reinforcing bush 6 project from the upper and lower seat surfaces of the mounting seat 1a when insert-molding the resin case 1. The reinforcing bush 6 may be insert-molded integrally with the resin case 1 or may be press-fitted into the screw hole 1b of the mounting seat 1a.

With such a configuration, when the resin case 1 is fixed by screwing the fastening screw 4 inserted into the screw hole 1b of the mounting seat 1a into the fixing portion 5 on the mating side, the upper and lower end surfaces of the reinforcing bush 6 are respectively fixed to the fixing portion. The reinforcing bush 6 receives the tightening force of the screw against the mounting surface 5 and the screw head 4a of the fastening screw 4, and the mounting seat 1a of the resin case 1 which is a resin molded product.
Is not subjected to screw tightening stress. Thereby, the fastening screw 4 is not loosened due to aging of the resin of the mounting seat 1a, and the resin case 1 can be fastened and fixed in a stable state for a long period of time.

[Embodiment 2] FIG. 2 shows an application embodiment corresponding to claim 2 of the present invention. In this embodiment, a screw hole 1 is provided on the upper surface of the mounting seat 1a of the resin case 1.
recess 1c surrounding screw b and into which the screw head of fastening screw 4 enters
(The hole diameter of the recess is larger than the diameter of the screw head 4a), and the upper end of the reinforcing bush 6 protrudes from the bottom.

With this configuration, the same function as that of the first embodiment can be obtained. In addition, since the upper end of the reinforcing bush 6 does not protrude from the mounting seat 1a, an object is placed on the reinforcing bush 6 during storage and handling of a product. Problems such as deformation due to hitting can be avoided.

[0012]

As described above, according to the structure of the present invention, when the resin case is screwed and fixed to the fixing portion on the mating side, the tightening force of the screw is applied to the mounting seat of the resin case. As a result, mechanical deterioration due to stress applied to the resin molded product and loosening of fastening screws as in the conventional structure can be prevented, and a stable fixed state can be maintained for a long period of time even in a severe use environment. The reliability of the product mounting structure is improved.

In addition, when the reinforcing bush is formed as an insert in the resin case, strict dimensional control of the reinforcing bush,
There is no need to take special considerations such as adjusting the clamping of the molding dies, which makes the quality control of molded products easier and improves the yield.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a mounting structure of a resin package according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a resin package mounting structure according to a second embodiment of the present invention;

FIG. 3 is an external view of a pressure sensor exemplified as an embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a conventional resin package mounting structure.

FIG. 5 is a diagram showing a state in which dimensional variation occurs in a mounting portion of a resin package in the conventional structure of FIG. 4;

[Explanation of symbols]

 Reference Signs List 1 resin case 1a mounting seat 1b screw hole 1c recess 4 fastening screw 4a screw head 5 fixing part 6 reinforcing bush

Claims (2)

[Claims] 1. A screw hole in which a metal reinforcing bush is inserted is provided in a mounting seat of a resin case made of a resin molded product for an electronic component or the like, and a fastening screw is inserted into the screw hole to form a mating member. When the screw is fixed to the fixed part on the side, the height of the reinforcing bush is set to be larger than the screw hole depth of the mounting seat, and the end face of the reinforcing bush is inserted from the seat surface of the mounting seat at the insert position to the mounting seat. Mounting structure of resin package characterized by protruding. 2. The mounting structure according to claim 1, wherein a recess is formed in the end surface of the mounting seat of the resin case so as to surround the screw hole and into which the screw head of the fastening screw enters. Construction.