JP2584227Y2 - Electronics - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device in which a thermosetting resin is filled in a main body case to which a printed wiring board is fixed.

[0002]

2. Description of the Related Art In an electromagnetic coupling type ID system, for example, a terminal device on a fixed side is installed so as to face an ID unit on a moving side, and the terminal device is electromagnetically coupled in a state where both are opposed to each other, so that an ID is transmitted from the terminal device. Data is written to and read from the unit.

FIG. 7 is an exploded view of an example of this type of terminal device. In FIG. 7, a coil bobbin 2 on which a coil 2a is wound is positioned on a bottom portion of a resin container body 1 having a flat container shape, and a printed wiring board 3 is provided.
In a state where the main body case 1 is fixed to the main body case 1, for example, an epoxy resin which is a thermosetting resin is filled in the main body case 1 to be cured.

In this case, the printed wiring board 3 has a rectangular shape, and a mounting hole 3a and a mounting slit 3b formed at diagonally located corners for simplifying the mounting work on the main body case 1. Is screwed to the main body case 1.

[0005]

Incidentally, the epoxy resin filled in the main body case 1 is hardened with self-heating, so that the main body case 1 and the printed wiring board 3 are thermally expanded by the generated heat. At this time, the linear expansion coefficient of the resin-made main body case 1 is larger than the linear expansion coefficient of the printed wiring board 3 made of a glass epoxy substrate. , A tensile stress inwardly acts on the printed wiring board 3. For this reason, the main body case 1 is warped due to the deformation, so that not only the appearance of the main body case 11 is not good, but also it is difficult to securely mount the main body case 1 to the installation surface due to rattling on the mounting surface. There are disadvantages.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a configuration in which a thermosetting resin is filled while a printed wiring board is housed in a main body case.
It is an object of the present invention to provide an electronic device capable of preventing a main body case from being deformed by heat generated when a thermosetting resin is cured.

[0007]

According to the present invention, there is provided a container-shaped resin main body case, and first and second mounting portions at diagonally located corners, the main body being connected via the mounting portions. A substantially rectangular printed circuit board fixed in the case,
In an electronic device in which the main body case is filled with a thermosetting resin in a state where the printed wiring board is fixed to the main body case, a division slit for dividing the first and second mounting portions is provided in the printed wiring board. It is a thing.

[0008]

The printed wiring board is fixed to the resin body via first and second mounting portions provided at corners located on diagonal lines of the printed wiring board. When the main body case is filled with the thermosetting resin, the thermosetting resin hardens with self-heating, so that the main body case and the printed wiring board are thermally expanded by the generated heat. At this time, since the linear expansion coefficient of the resin main body case is generally larger than the linear expansion coefficient of the printed wiring board, the difference in the two linear expansion rates causes the main body case to move inward from the printed wiring board. Tensile stress acts. However, since the mounting portion of the printed wiring board is formed with a dividing slit for separating between the first and second mounting portions facing each other, when a tensile stress acts outward on the printed wiring board by the main body case. In
Since the dividing slit expands so as to absorb the tensile stress acting on the main body case, it is possible to prevent the main body case from warping due to deformation.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is applied to a terminal device of an ID system will be described below with reference to FIGS. The terminal device is arranged, for example, so as to face an ID unit attached to an article conveyed by a belt conveyor, and reads and writes data with the ID unit by electromagnetic coupling. .

In FIG. 1, which is an exploded view of a terminal device, a coil bobbin 12 is positioned on the inner bottom surface of a flat container-shaped main body case 11. This coil bobbin 12
A winding portion 14 having an annular groove is formed integrally with a peripheral portion of the disk-shaped portion 13 and a coil 15 is wound around the winding portion 14. By fitting the formed fitting hole 13a to the fitting projection 11a formed at the center of the main body case 11, the positioning in the main body case 11 is performed in a state where the movement in the lateral direction is restricted.

On the other hand, a rectangular printed wiring board 16 made of a glass epoxy board on which a control circuit is mounted is fixed in the main body case 11. FIG. 2 shows a printed wiring board 1
6 is shown. 2, a mounting hole 16a as a first mounting portion is formed at one corner located on a diagonal line of the printed wiring board 16, and a mounting slit 16b as a second mounting portion is formed at the other corner. Is formed. Also,
An L-shaped dividing slit 16c is formed at each corner of the printed wiring board 16 so as to surround the mounting hole 16a and the mounting slit 16b. With such a configuration, the mounting slits 16a and the mounting slits 16b formed in the corners of the printed wiring board 16 are separated by the respective split slits 16c.

In FIG. 1, the printed wiring board 16 has a stud 1 protrudingly formed on the bottom surface of the main body case 11 through a mounting hole 16a and a mounting slit 16b.
1b. In this case, the printed wiring board 1
6, the mounting slit 16b is opposed to the mounting hole 16a.
Is formed by connecting the printed wiring board 16 to the main body case 1.
This is to allow a dimensional error between the printed wiring board 16 and the main body case 11 when screwing the printed wiring board 1 to the screw 1.

Here, a silicon resin 17 is applied on the upper surface of the printed wiring board 16 as shown in FIG.
The silicon resin 17 protects an electronic component 18 such as a chip component mounted on the upper surface of the printed wiring board 16. Further, the printed wiring board 1 is provided in the main body case 11.
3, the printed wiring board 16 is in contact with the upper surface of the coil bobbin 12, as shown in FIG. 3, and the arrangement thereof restricts the upward movement of the coil bobbin 12.

In FIG. 1, a cable attaching portion 19 is formed on a side wall of the main body case 11, and a cable packing 20 and a packing presser 21 are formed on the cable attaching portion 19.
The cable 22 is attached via the. This cable 22
Is connected to a control circuit mounted on the printed wiring board 16, and the control circuit is connected to the coil 15 wound around the coil bobbin 12.

The main body case 1 in which the coil bobbin 12 and the printed wiring board 16 are positioned as described above.
1 is filled with an epoxy resin 23 as a thermosetting resin up to the upper surface. When the epoxy resin 23 is cured, the coil bobbin 12 and the printed wiring board 16 housed in the main case 11 are buried in the main case 11. (See FIG. 3). Here, a glass bead having a diameter of about 1 mm is mixed in the epoxy resin 23. This is because the cost of the glass beads is lower than the unit price of the epoxy resin of the same amount and the cost can be reduced, and the thermal expansion of the glass beads is extremely small, and the thermal expansion of the entire filling resin including the glass beads can be reduced. .

The terminal device having the above configuration is screwed to a mounting portion (not shown) via a mounting hole 11c (see FIG. 1) formed in the main body case 11.

In order to assemble the terminal device having the above structure, the coil bobbin 12 is fitted in a state where the coil bobbin 12 is fitted to the fitting projection 11a on the inner bottom surface of the main body case 11. Subsequently, when the printed wiring board 16 is screwed to the stud 11b of the main body case 11, the coil bobbin 12
And the printed wiring board 16 is positioned.

When the epoxy resin flows into the main body case 11, the epoxy resin 23 has the property of being hardened by self-heating, so that the main body case 11 and the printed wiring board 16 housed in the main body case 11 are hardened by the epoxy resin 23.
Temperature rises due to heat from At this time, since the main body case 11 is made of resin and the printed wiring board 16 is a glass epoxy board, the linear expansion coefficient of the main body case 11 is larger than the linear expansion coefficient of the printed wiring board 16. For this reason, they are pulled from each other based on the difference between the linear expansion coefficients, so that an inward tensile stress acts on the main body case 11 and an outward tensile stress acts on the printed wiring board 16.

Here, since the dividing slit 16c for dividing the mounting hole 16a and the mounting slit 16b is formed in the printed wiring board 16, the mounting slit 16c and the mounting slit 16b of the printed wiring board 16 are formed as described above. When a tensile stress acts outward from the main body case 11, the dividing slit 16c expands so as to absorb the tensile stress. As a result, an outward tensile stress is prevented from acting on the printed wiring board 16, and as a reflex action, the printed wiring board 16 is attached to the main body case 11.
It can prevent that a tensile stress acts inward from the inside. After that, the epoxy resin 23
Is completely cured, the coil bobbin 12 and the printed wiring board 16 are integrated into the main body case 11 in a form embedded in the epoxy resin 23.

According to the above configuration, the main body case 11
A dividing slit 16c for dividing the mounting hole 16a and the mounting slit 16b provided in the printed wiring board 16 fixed therein is formed, and the tensile stress applied from the main body case 11 to the printed wiring board 16 is divided by the dividing slit 16c.
Therefore, it is possible to prevent the main body case 11 from being warped due to deformation due to an outward tensile stress acting on the main body case 11. Therefore, unlike the conventional example in which the printed wiring board is simply mounted in the main body case through the mounting hole, it is possible to prevent a problem that the appearance is deteriorated and the printed wiring board cannot be mounted on the installation portion.

Further, according to the above embodiment, the coil bobbin 12 housed in the main body case 11 is
1 can be prevented from being lifted up by the warpage of the coil bobbin 1.
The detection distance between the terminal 2 and the ID terminal does not fluctuate, and the coil bobbin 12 does not tilt with respect to the ID terminal, so that the communication between the terminal device and the ID terminal can be reliably performed.

FIG. 4 shows a printed wiring board 16 according to a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different parts will be described. That is, the printed wiring board 16 is formed with a mounting slit 16d as a first mounting portion in place of the mounting hole 16a in the first embodiment, and the separation slit 16 between the mounting slit 16d and the mounting slit 16b is formed.
c.

According to the second embodiment, the printed wiring board 16 can be mounted on the main body case 11 through the mounting slits 16b and 16d. The tolerance of the dimensional accuracy of the substrate 16 and the body case 11 can be set large.

FIG. 5 shows a printed wiring board 16 according to a third embodiment of the present invention. That is, instead of the mounting slit 16b in the first embodiment, a mounting hole 16e as a second mounting portion is formed in the printed wiring board 16, and the same operation and effect as those in the first embodiment can be obtained.

FIG. 6 shows a printed wiring board 16 according to a fourth embodiment of the present invention. That is, the protruding portion 22 is integrally formed on the rectangular printed wiring board 16,
A mounting hole 22a is formed in the protruding portion 22, and a linear dividing slit 22b that divides between the mounting hole 16a and the mounting hole 22a is formed.

According to the fourth embodiment, the mounting holes 16a and 22a formed in the printed wiring board 16 are divided by the dividing slits 22b, so that the same operation and effect as in the first embodiment can be obtained. .

In the first to third embodiments, the dividing slits are formed at the diagonally located corners of the printed wiring board 16, but the dividing slits are formed only at one corner. Is also good.

[0028]

As is apparent from the above description, according to the electronic device of the present invention, the first and second electronic devices are mounted on the printed wiring board mounted on the main body case through the first and second mounting portions. When the heat is applied to the main body case and the printed circuit board due to the heat generated by the thermosetting resin filled in the main body case and the main body case is thermally expanded due to the difference in the linear expansion rates of the two, a mutual slit is formed. Even if tensile stress is applied to each other, the splitting slits formed in the printed wiring board absorb the tensile stress from the main body case. In the configuration in which the resin is filled, there is an excellent effect that the main body case can be prevented from being deformed by heat generated when the thermosetting resin is cured. That.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a terminal device according to a first embodiment of the present invention.

FIG. 2 is a plan view of a printed wiring board.

FIG. 3 is a longitudinal sectional view of a terminal device.

FIG. 4 is a view corresponding to FIG. 2 showing a second embodiment of the present invention;

FIG. 5 is a view corresponding to FIG. 2, showing a third embodiment of the present invention;

FIG. 6 is a view corresponding to FIG. 2, showing a fourth embodiment of the present invention;

FIG. 7 is a diagram corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

11 is a main body case, 12 is a coil bobbin, 16 is a printed wiring board, 16a is a mounting hole (first mounting portion), 16b
Is a mounting slit (second mounting portion), 16c is a dividing slit, 16d is a mounting slit (first mounting portion), 16e is a mounting hole (second mounting portion), and 22a is a mounting hole (second mounting portion). ) And 23 are epoxy resins (thermosetting resins).

Claims (1)

(57) [Scope of request for utility model registration] 1. A substantially rectangular container having a container-shaped resin main body case and first and second mounting portions at corners located diagonally and fixed in the main body case via the mounting portions. An electronic device comprising a printed wiring board having a shape, wherein the main body case is filled with a thermosetting resin in a state where the printed wiring board is fixed to the main body case; An electronic device, comprising a dividing slit for dividing between the mounting portions.