JPH1051158A - Circuit device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent water from penetrating in the inside of a circuit device from the gap between a lid body and a box body by a method wherein a rib which protrudes from the edge part of the lid body to the inner side of the box body is formed integrally, the inside of the box body is filled with a resin and the resin comes into contact with the rib. SOLUTION: A lid body 4 is provided with a rib 12 which is formed integrally so as to protrude perpendicularly to the rear surface 11a of a main part 11 at the lid body 4 over nearly the whole circumference from a position a little to the inside of the peripheral edge part of the rear surface 11a. In addition, A starter circuit board 20 and a ballast circuit board 21 are fixed to the bottom plate 5 of a box body 3 in a starter-circuit housing part 9 and a ballast-circuit housing part 10 inside a case body 2 which is composed of the box body 3 and of the lid body 4. Then, a urethane resin is filled into the case body 2 in such a way that it covers the starter circuit board 20 and the ballast circuit board 21 from the bottom plate 5 of the box body 3 and that it reaches a height coming into contact with the lower end of the rib 12 protruding from the rear surface 11 a of the lid body 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit device having improved waterproofness, earthquake resistance and heat dissipation.

[0002]

2. Description of the Related Art A circuit board on which electronic components are mounted is housed in a box made of, for example, a substantially container-shaped synthetic resin or metal, and its opening is covered with a lid made of the same material as the box. There is a circuit device that is hermetically sealed to improve the waterproofness of electronic components.

In such a circuit device,
At the joint between the lid and the box, a synthetic rubber packing is interposed between the lid and the box to eliminate gaps and prevent water from entering the inside.

[0004]

However, in the above-described circuit device, the synthetic rubber used as a packing or a bushing is susceptible to oil and high heat, and thus easily deteriorates. Therefore, if the packing or bushing deteriorates, a gap is formed between the lid and the box, and water can enter the circuit device through this gap, causing rust and corrosion on the electronic components and metal parts of the circuit board. , There is a problem of causing a leak.

[0005] In particular, since a heat source such as an engine that emits oil or high heat is present in the vicinity, it is even more so in a circuit device used for an automobile in an environment where packing and a bushing are more likely to deteriorate.

[0006]

Therefore, in the circuit device of the present invention, when the opening of the box is covered with the lid, a rib projecting from the edge of the lid toward the inner surface of the box is integrally formed. In addition, the inside of the box is filled with resin so that the resin comes into contact with the ribs.

Therefore, a gap is formed at the joint portion between the lid and the box, and even if water enters from there, the ribs of the lid and the resin inside the box are in contact immediately inside the case. internal,
In particular, water does not penetrate into the portion inside the rib where the circuit board is disposed, and rust and corrosion of the metal portion in the case body and leakage of current can be prevented.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the circuit device according to the present invention will be described below with reference to an embodiment shown in the accompanying drawings.

The circuit device 1 is mainly constituted by housing a circuit board on which electronic components are mounted in a case 2 made of a rectangular box-shaped metal, for example, an aluminum alloy die-cast (ADC). Further, the case body 2 includes a container-like box body 3 having a substantially rectangular shape in a planar shape opened toward one side, and a lid body 4 covering the opening of the box body 3. And
From the case body 2, connection codes to be described later are led out at two places.

The circuit device 1 of the present embodiment is obtained by applying the circuit device of the present invention as a lighting circuit device of a discharge lamp for a vehicle having a ballast circuit and a starter circuit.

In the following description, when describing the directions of up, down, front, rear, left and right, the up and down directions in FIG. 1 are referred to as left and right directions, the left and right directions are referred to as front and rear directions, and the up and down in FIG.

As shown in FIGS. 2 and 3, the box body 3 has a peripheral wall 6 which rises substantially vertically from the peripheral edge of the bottom plate 5 over the entire periphery thereof, and opens upward. It has a shallow depth, as compared to its length and width, that is, a slightly flat rectangular container shape. A small step 6a facing outward is formed on the upper end surface of the peripheral wall 6 over the entire circumference.

At the four corners of the box 3, the thickness of the peripheral wall 6 is increased so that screw holes 7 for fixing the lid 4 to the box 3 are formed.
The bosses 7, 7,... formed with a, 7a,... are formed. Further, as shown in FIG. The partition 8 is formed in a substantially L shape from a position slightly closer to the right of the rear wall of the peripheral wall 6 to a position closer to the front of the right wall.
As a result, a starter circuit housing portion 9 as a right rear portion and a ballast circuit housing portion 10 as other portions are formed.

As shown in FIGS. 2 and 4, the lid 4 has a main portion 11 formed in a substantially plate shape having substantially the same planar shape and size as the bottom plate 5 of the box 3, and the main portion 11. 11 lower surface 11
and a rib 12 integrally formed so as to project perpendicularly to the lower surface 11a over substantially the entire periphery from a position slightly inward of the peripheral edge portion a. As shown in FIG. 4, a substantially U-shaped notch 13 is formed at a position closer to the front of the right edge of the main portion 11. In the portion where the notch 13 is formed, the rib 12 is formed in a substantially U-shape along the outer edge of the notch 13.

Also at the four corners of the lid 4 corresponding to the positions of the bosses 7, 7,... Formed at the four corners of the box 3, the bosses 7, 7,. The ribs 12 are formed in a curved shape corresponding to..., And screw insertion holes 4a, 4a,.

The outer edge 14 of the lid 4 further outward than the ribs 12 is spaced apart from the ribs 12 by a certain distance except for the portion where the notch 13 is formed, and has a main portion. 11 is formed to be slightly thicker than other portions, and therefore, a sealing groove 15 is formed between the rib 12 and the outer edge portion 14.

Further, a circular opening 16 is provided at a position slightly to the right of the center of the main portion 11 of the lid 4. Also, as shown in FIGS. 1 and 2, upright walls 17 and 18 are provided concentrically on the upper surface 11 b of the main portion 11 so as to surround the opening 16.
The inner standing wall 17 protruding from the opening edge of the opening 6 has a height slightly higher than the outer standing wall 18 from the upper surface 11b of the main portion 11. The standing wall 17 protrudes toward the center of the opening 16 from three places 120 degrees apart from each other.
Boss portions 19, 19, 19 having screw holes 19a are formed.

The starter circuit housing 9 and the ballast circuit housing 10 in the case body 2 composed of the box body 3 and the lid body 4 having the above-described structures are provided with starter circuit boards on which appropriate electronic components are mounted. The ballast circuit board 20 and the ballast circuit board 21 are fixed to the bottom plate 5 of the box body 3 by an appropriate method.

As shown in FIG. 2, a sponge-like urethane resin 22 is provided in the case 2 in the bottom plate 5 of the box 3.
From the starter circuit board 20 and the ballast circuit board 2
1 and is further filled to a height that contacts the lower end of the rib 12 protruding from the lower surface 11 a of the lid 4. still,
The urethane resin 21 is formed by filling the case body 2 with a liquid so-called gel state (urethane gel) and then curing. A method of sealing the urethane resin 22 in the case body 2 and curing the urethane resin 22 from the gel state will be described later.

The circuit boards 20 and 21 have cords 23, 23 and 24 for electrically connecting to a discharge lamp and a battery as a power source, respectively, which are not shown.
24 are connected.

That is, one end of each of the cords 23, 23 is connected to the starter circuit board 20, is led out from the opening 16 of the lid 4, and the other end is connected to a discharge lamp as shown in FIG. Connector 25 is connected.

In the middle part of the cords 23, 23, an outer peripheral surface of a tube made of a synthetic resin such as a synthetic rubber having flexibility and insulation properties is formed by, for example, stainless steel (SUS) or the like. A tube body 26 covered with a metal mesh made of is externally fitted.

The tube 26 has one end fixed to the lid 4 using a holder 27 and a collar 28, and the other end fixed to the cords 23 by appropriate taping. That is, the holder 27 to which the tube body 26 is fixed is aligned with the end face of the upright wall 16 of the lid 4, and a screw is inserted into the screw insertion hole of the flange to be inserted into the screw holes 19 a, 19 a, 19 a of the boss portions 19, 19, 19. It is fixed to the lid 4 by screwing.

One end of each of the cords 24, 24 is connected to the ballast circuit board 21.
A connector 29 for connecting to the battery is connected to the other end of the case body 2, which is led out of the case body 2 from the portion opened by 3. A flexible bushing 30 made of synthetic resin such as synthetic rubber is fitted into the notch 12 of the lid 4 to close the opening and to hold the cords 24, 24.

The starter circuit board 20 and the ballast circuit board 21 are electrically connected by a cord (not shown).

Next, the urethane resin 22
Will be described.

That is, first, members that come into contact with the urethane resin 22 such as the case body 2 are dried. This is because urethane resin in a urethane gel state easily reacts with moisture.

Next, in order to make it difficult for bubbles to be formed in the urethane gel, the starter circuit board 20 and the ballast circuit board 21 are housed and fixed in a reduced pressure atmosphere, and the cords 23, 23, 24, 24 Is led out of the box 3, and when the urethane resin 22 in a gel state is closed in the box 3 as shown in FIG. It is poured into a position where it contacts the rib 12 of the body 4 (potting).

After applying a liquid gasket using a silicone-based adhesive to the sealing groove 15 of the lid 4, the opening of the box 2 is covered with the lid 4 and closed.
.. Are inserted into the screw insertion holes 4a, 4a,... Of the lid 4, and the screw holes 7a, 7a, 7 of the boss portions 7, 7, 7 of the box 3 are inserted.
The cover 4 is fixed to the box 2 by screwing it into a.
At this time, the rib 12 of the lid 4 is located inside the peripheral wall 6 of the box 3, and the step 6 a of the box 3 is engaged with the outer peripheral edge 14 of the lid 4 and the sealing groove 15. Also, code 23,
Reference numerals 23, 24, and 24 are respectively derived from the opening 16 and the notch 13 of the lid 4.

Finally, in order to harden the urethane gel by applying heat, the case body 2 is placed in a curing furnace and subjected to a heat treatment at a temperature of 80 ° C. for 4 hours, whereby the urethane gel solidifies as described above. It becomes a sponge-like urethane resin.
The silicone-based adhesive applied as a liquid gasket to the sealing groove 15 of the lid 4 cures at room temperature.
It cures even at a temperature of 0 ° C.

As shown in FIG. 2, the circuit device 1 has the upright wall 17 fitted inside the opening 33 of the lamp body 32 of the vehicle lamp and is fixed to the lamp body 32 by an appropriate method. Attached by

As described above, if the inside of the case body 2 is filled with urethane gel and the periphery of each of the circuit boards 20 and 21 is sealed in the urethane resin 22, the urethane resin 20 absorbs vibration. It is possible to prevent the occurrence of cracks and the like in the soldered portions of the electronic components on each of the circuit boards 20 and 21 due to intense vibration, thereby preventing disconnection.

Further, since the heat generated by the electronic components on each of the circuit boards 20 and 21 is transmitted to the metal case 2 by the urethane resin 22 having a higher thermal conductivity than air,
The heat dissipation inside the case body 2 is improved.

The reason that the urethane resin 22 is used as the resin filling the inside of the case body 2 is that the electronic component is pulled by the resin filled therein due to the expansion and contraction of the resin due to heat, and is broken. This is because the urethane resin 22 having elasticity when cured is optimal in order to prevent this.

[0035]

As is apparent from the above description, the circuit device according to the first aspect of the present invention is arranged such that when the opening of the box is covered with the lid, the circuit device is moved from the edge of the lid to the inner surface of the box. Since the ribs that protrude are provided integrally and the inside of the box is filled with resin so that the resin comes into contact with the ribs, a gap is formed at the joint between the lid and the box, from which water is discharged. Even if it enters, the ribs on the lid and the synthetic resin inside the box are in contact immediately inside, so that water does not enter the inside of the case, especially the part where the circuit board is placed, Rust and corrosion of metal parts and leakage of current can be prevented.

Further, in the circuit device according to the second aspect, in addition to the configuration according to the first aspect, the rib is provided along the entire periphery along the outer edge of the lid, so that the inside and outside of the rib are provided. Can be completely isolated, and higher waterproofness can be obtained.

It should be noted that the specific shapes and structures shown in the above-described embodiments are merely examples of the embodiment for carrying out the present invention, and the technical scope of the present invention is limited thereby. Is not to be interpreted.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of a circuit device of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a plan view of a box.

FIG. 4 is a bottom view of the lid.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Circuit device, 2 ... Case body, 3 ... Box body, 4 ... Lid body, 1
2 ... rib, 20 ... circuit board, 21 ... circuit board, 22 ... resin

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toru Nakayama 500 Kitawaki, Shimizu City, Shizuoka Prefecture Inside the Koito Manufacturing Shizuoka Plant (72) Inventor Shoichiro Yoko 500 Kitawaki Shimizu City, Shizuoka Prefecture Koito Manufacturing Shizuoka Plant

Claims (2)

[Claims] A circuit board on which electronic components are mounted is housed in a case body including a container-like box having an opening opening toward one side and a lid covering the opening of the box. When the opening of the box is covered with a lid, a rib is provided integrally so as to protrude from the edge of the lid toward the inner surface of the box, and the inside of the box is provided. A circuit device, wherein a resin is filled so that the resin comes into contact with the rib. 2. The circuit device according to claim 1, wherein the rib is provided along the entire periphery along the outer edge of the lid.