JP2000228243A - Ventilation of waterproof case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent both a short circuit inside a connector and a short circuit of a circuit board due to water absorption by making both the inside of a waterproof case and inside of the connector communicate with the open air. SOLUTION: In a connector 20 of a wire harness 19, plural vent holes 23 for making the inside of the connector 20 communicate with the open air are formed in the connector 20 of a wire harness 19, and water repellent filters 24 having both ventilation and waterproofing are mounted to the vent holes 23 by means of welding or the like. On the other hand, one or more communicating holes 25 for making the inside of the connector 20 of the wire harness 19 communicate with the inside of a waterproof case 11 are formed in a connector 17 of a circuit board 16 received in the waterproof case 11. Thus, both the inside of the waterproof case 11 and the inside of the connector 20 are made to communicate with the open air through the vent holes 23 and the communicating holes 25, so that water absorption due to a negative pressure can be prevented and both a short circuit inside the connector 20 and a short circuit of the circuit board 16 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof case ventilation structure in which the inside of a waterproof case communicates with the atmosphere.

[0002]

2. Description of the Related Art Conventionally, an electronic engine control circuit of an automobile has been housed in a waterproof case to protect it from rainwater and moisture. Since this waterproof case is disposed in the engine room, it is exposed to a relatively large temperature change. Therefore, when the waterproof case has a completely sealed structure, the internal pressure of the waterproof case changes due to a temperature change, and a pressure difference occurs between the internal pressure of the waterproof case and the atmospheric pressure. When the pressure difference is large, the waterproof case may be deformed, and the waterproofness of the seal portion may be reduced. As a result, moisture may enter the waterproof case from the seal portion to cause a failure such as a short circuit on the circuit board. There is a risk.

Therefore, there is a waterproof case in which a vent hole communicating with the atmosphere is formed to keep the inside of the waterproof case at the same atmospheric pressure.

[0004]

By the way, a connector of a circuit board housed in the waterproof case is penetrated and fixed to one side of the waterproof case, and a connector of a wire harness is inserted and connected to the connector of the circuit board. I have to.
Since the space between the connector of the wire harness and the waterproof case is sealed with rubber packing or the like, the connection portion of the connector is in a sealed state. For this reason, a pressure difference occurs between the inside of the connection portion of the connector and the atmospheric pressure due to the temperature change.

[0005] In particular, since the temperature in the engine room where the waterproof case is arranged rises to about 100 ° C during running, if the car is washed in a high temperature state in the engine room,
The temperature inside the engine room is rapidly lowered by the washing water, and the temperature inside the connector is also rapidly lowered, so that the inside of the connector may become negative with respect to the atmospheric pressure. When the negative pressure increases, moisture may be sucked into the connector through the wire harness, and a short circuit may occur inside the connector due to the water absorption. In short, in the above-described conventional structure, the inside of the waterproof case can be kept at the same pressure as the atmospheric pressure through the ventilation holes of the waterproof case. A short circuit may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object thereof is to prevent the inside of the connector and the inside of the waterproof case from becoming negative with respect to the atmospheric pressure. An object of the present invention is to provide a waterproof case ventilation structure that can prevent both an internal short circuit and a circuit board short circuit.

[0007]

In order to achieve the above object, the ventilation structure of the waterproof case according to the first aspect of the present invention includes an external connector which is inserted into and connected to a connector of a circuit board.
A vent hole for communicating the inside of the connector with the atmosphere is formed, and a communicating hole for communicating the inside of the external connector and the inside of the waterproof case is formed in the connector of the circuit board. In this ventilation structure, since the inside of the external connector is communicated with the atmosphere through the vent formed in the connector, the inside of the external connector is kept at the same atmospheric pressure regardless of the temperature change. The occurrence of water absorption due to a pressure difference inside the connector is prevented, and a short circuit between terminals inside the connector is prevented. Furthermore, since the inside of the waterproof case is communicated with the atmosphere through the communication hole formed in the connector of the circuit board and the vent hole of the external connector, the inside of the waterproof case is kept at the same atmospheric pressure regardless of the temperature change. It is kept, preventing intrusion of moisture into the waterproof case,
Short circuit of the circuit board in the waterproof case is prevented.

Since the waterproof case is designed according to the size, shape and type of the circuit board to be housed, there are waterproof cases of various sizes, shapes and materials. A common connector is often used for a waterproof case made of a material. Therefore,
Forming ventilation holes and communication holes in two connectors that are made into a common component as in the present invention allows ventilation at a lower cost at a lower cost than forming ventilation holes in many types of waterproof cases. And can meet the demand for cost reduction.

In this case, it is preferable to provide a water-repellent filter having both air permeability and waterproofness in the vent hole of the external connector. In this case, the intrusion of moisture from the vent hole of the external connector can be reliably prevented by the water-repellent filter. However, the present invention is not limited to the configuration in which the water-repellent filter is provided. Alternatively, the intrusion of moisture from the ventilation holes may be prevented.

Further, a plurality of ventilation holes may be formed in the external connector. If you do this,
Compared to the case of securing ventilation with only one ventilation hole,
Since the diameter of each ventilation hole can be reduced, foreign substances are less likely to enter into each ventilation hole, and even if one ventilation hole is clogged with a foreign substance, it is possible to reliably secure air permeability with another ventilation hole, Durability can be improved.

Further, it is preferable that the vent hole is formed so as to penetrate in the same direction as the penetrating direction of the terminal of the connector. With this configuration, the molding of the connector can be performed with a simple two-part mold, and the molding cost of the connector can be reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment (1) of the present invention will be described below with reference to FIGS. The waterproof case 11 shown in FIGS. 1 and 3 includes a case body 12 and a cover 13 for closing an opening on the lower surface of the case body. An engaging piece 14 formed on the cover 13 is formed on the case body 12. The cover 13 is fixed to the case body 12 by engaging with the engaged portion 15. In this waterproof case 11,
A circuit board 16 on which an engine electronic control circuit and the like are mounted is housed. A male connector 17 is provided on the circuit board 16 in a horizontal direction, and the connector 17 is fitted and fixed from inside to a connector fitting portion 18 formed on a side surface of the case body 12.

On the other hand, a female connector 20 made of resin is provided at a distal end of a wire harness 19 serving as a signal line and a power supply line connected to an engine electronic control circuit in the waterproof case 11. Connector 20 of this wire harness 19
The terminal 21 of the connector 20 of the wire harness 19 is inserted into and connected to the terminal 22 of the connector 17 of the circuit board 16 by fitting the terminal 21 into the connector fitting portion 18 of the waterproof case 11 from the outside. The space between the connector 20 of the wire harness 19 and the connector fitting portion 18 of the waterproof case 11 is sealed by rubber packing (not shown) or the like.

Each of the two connectors 17 and 20 has a housing portion formed of resin, and further has a wire harness 1.
A plurality of ventilation holes 23 for communicating the inside of the connector 20 with the atmosphere are formed in the connector 20 of No. 9 so as to penetrate in the same direction as the direction in which the terminals 21 of the connector 20 penetrate. A water-repellent filter 24 having both air permeability and waterproofness is assembled to the plurality of ventilation holes 23 from the inside by welding or the like. The water repellent filter 24 is formed of, for example, a porous structure of polytetrafluoroethylene.

On the other hand, the connector 17 of the circuit board 16
One or a plurality of communication holes 25 for communicating the inside of the connector 20 of the wire harness 19 and the inside of the waterproof case 11 are formed so as to penetrate in the same direction as the direction of the terminal 22. Furthermore, a connector 20 formed between the connector 20 of the wire harness 19 and the connector 17 of the circuit board 16
The entire internal space is formed so as to communicate with the communication hole 25. In other words, it is formed so that the space inside the connector 20 does not become a plurality of separated closed spaces.

According to the embodiment (1) described above, the inside of the connector 20 of the wire harness 19 is communicated with the atmosphere through the air holes 23 formed in the connector 20, so that the inside of the connector 20 does not depend on the temperature change. The inside of the connector 20 of the wire harness 19 is kept at the same pressure as the atmospheric pressure, so that water absorption due to a pressure difference inside the connector 20 is prevented, and a short circuit between the terminals 21 inside the connector 20 is prevented. Further, since the inside of the waterproof case 11 is communicated with the atmosphere by the communication hole 25 of the connector 17 of the circuit board 16 and the ventilation hole 23 of the connector 20 of the wire harness 19, the waterproof case 11 is not affected by a temperature change. Is maintained at the same level as the atmospheric pressure, so that the intrusion of moisture into the waterproof case 11 is prevented, and the short circuit of the circuit board 16 in the waterproof case 11 is prevented.

Moreover, since the air hole 23 and the communication hole 25 are formed in the two connectors 20 and 17 which are made into a common component,
The waterproof case 11 can be provided with air permeability at a lower cost as compared with the case where vents are formed in various waterproof cases 11 having different sizes, shapes, and materials, and the demand for cost reduction can be satisfied. .

Further, the connector 20 of the wire harness 19
Since the water repellent filter 24 is provided in the vent hole 23 of the connector 20, the intrusion of moisture from the vent hole 23 of the connector 20 can be reliably prevented by the water repellent filter 24. Moreover, since the connector 20 is formed of resin, there is an advantage that the water-repellent filter 24 can be easily assembled by welding (if the waterproof case 11 is formed of a metal such as aluminum, the waterproof case 11 is temporarily attached to the waterproof case 11). Even if the air holes are formed, it is difficult to weld the water-repellent filter).

However, the present invention is not limited to the configuration in which the water repellent filter 24 is provided. By providing it in a difficult position, it is possible to prevent the intrusion of moisture from the vent hole 23. In this case,
It is not necessary to provide a water-repellent filter.

Further, in the embodiment (1), since a plurality of ventilation holes 23 are formed in the connector 20 of the wire harness 19, each ventilation hole is compared with the case where only one ventilation hole is used to secure the air permeability. 23 can be reduced in diameter. For this reason, it becomes difficult for a foreign substance to enter into each ventilation hole 23,
Even if one vent hole 23 is clogged with a foreign substance, the other vent holes 23 can reliably ensure air permeability and improve durability. However, the present invention may have a configuration in which air permeability is ensured with only one vent hole, and even in this case, the intended object of the present invention can be sufficiently achieved.

The ventilation hole 23 is connected to the terminal 2 of the connector 20.
Since the connector 20 is formed so as to penetrate in the same direction as the penetration direction, the connector 20 can be molded by a simple two-part mold, and the molding cost of the connector 20 can be reduced.

However, in the present invention, the ventilation hole may be formed so as to penetrate in a direction different from the direction in which the terminal 21 of the connector 20 penetrates. Even in this case, the intended object of the present invention can be sufficiently achieved. .

For example, in the embodiment (2) of the present invention shown in FIG. 4, one or a plurality of ventilation holes 31 for communicating the inside of the connector 20 with the atmosphere are provided above the connector 20 of the wire harness 19. And a water-repellent filter 32 is attached to the inlet of the ventilation hole 31 by welding or the like. In the connector fitting portion 18 of the waterproof case 11, a ventilation hole 33 is provided just above the water-repellent filter 32.
Is formed. Other configurations are the same as those of the embodiment (1).
Is the same as

Also in the embodiment (2) having such a configuration, the communication hole 25 of the connector 17 of the circuit board 16 and the communication hole 25 of the connector 20 of the wiring harness 19 are used.
Both the inside of the connector 20 of the wire harness 19 and the inside of the waterproof case 11 can be kept at the same atmospheric pressure, and both short circuit inside the connector 20 due to water absorption and short circuit of the circuit board 16 can be prevented.

It should be noted that the present invention is not limited to the waterproof case containing the engine electronic control circuit, but includes the waterproof case containing various electronic control circuits mounted on the vehicle and the electronic control circuit of devices other than the vehicle. It can be applied to waterproof case.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view showing a ventilation structure of a waterproof case according to an embodiment (1) of the present invention.

FIG. 2 is a perspective view of a connector of a wire harness.

FIG. 3 is an external perspective view of the entire waterproof case.

FIG. 4 is a partial longitudinal sectional view showing a ventilation structure of a waterproof case according to the embodiment (2) of the present invention.

[Explanation of symbols]

11: waterproof case, 12: case body, 13: cover,
16 circuit board, 17 connector, 18 connector fitting portion, 19 wire harness, 20 connector 21, 21
2 ... terminal, 23 ... vent, 24 ... water-repellent filter, 25 ...
Communication hole, 31: vent hole, 32: water-repellent filter.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Nobuhiro Takano 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Yasuo Ito 1-1-1, Showa-cho, Kariya-shi, Aichi Co., Ltd. F term in DENSO (reference) 4E360 AB14 BD02 BD10 GA29 GB99 5E087 EE02 EE14 FF03 FF06 FF12 HH01 HH02 LL02 LL17 MM02 MM05 QQ04 RR12 RR31 RR49

Claims (4)

[Claims] 1. A circuit board is accommodated in a waterproof case, a connector provided on the circuit board is fixed through one side of the waterproof case, and an external connector is inserted and connected to the connector of the circuit board. A communication hole for communicating the inside of the external connector and the inside of the waterproof case with the connector of the circuit board, while forming a ventilation hole for communicating the inside of the connector with the atmosphere in the external connector. The ventilation structure of the waterproof case, characterized by forming a. 2. A water-repellent filter having both air permeability and waterproofness is provided in said vent hole.
The ventilation structure of the waterproof case according to 1. 3. The ventilation structure for a waterproof case according to claim 1, wherein a plurality of the ventilation holes are formed in the external connector. 4. The ventilation structure for a waterproof case according to claim 1, wherein the ventilation hole penetrates in the same direction as the penetration direction of the terminal of the external connector.