1. Technical Field
The present invention relates to a switch device that performs ON/OFF of a switch by operation of an operation knob, and particularly to a waterproof switch device that prevents water from coming into a connector.
2. Related Art
A vehicle such as an automobile includes a switch device to perform opening/closing control over windows, locking/unlocking control over doors or the like, and this type of switch device is generally provided in a door armrest, a center console or the like.
The above-described switch device includes, for example, a case 1′, a cover 9′ that covers an upper surface of the case 1′, and operation knobs 81′, as shown in 100′ of FIG. 17.
In FIG. 17, arrow F indicates a front direction of the switch device 100′. Hereinafter, similarly, arrow B indicates a back direction, arrow R indicates a right direction, arrow L indicates a left direction, arrow U indicates an upper direction, and arrow D indicates a down direction. Thus, FIG. 17 is a side view when the switch device 100′ is viewed from the left side.
The case 1′ is made up of an upper case 2′ opened downward, and a lower case 3′ attached to the upper case 2′ so as to shut this opening. Inside the case 1′, electronic components such as a printed circuit board 71′ and switches 72′ are contained. A connector 5′ is mounted on a lower surface of the printed circuit board 71′.
The connector 5′ has a housing 6′ and connection terminals 7′ supported by this housing 6′. The lower case 3′ is formed with an opening portion 33′, and the connector 5′ is fitted in this opening portion 33′ to be attached to the printed circuit board 71′ through the housing 6′ and the connection terminals 7′.
The housing 6′ has, at one end portion thereof, an opening portion 6a′ made of a depressed portion. Also, in another end portion of the housing 6′, a shielding wall 61′ with through-holes 62′ which the connection terminals 7′ penetrate. One end portion 7a′ of each of the connection terminals 7′ is connected to the printed circuit board 71′ by soldering. Another end portion of each of the connection terminals 7′ is led out to the opening portion 6a′ as a connection portion 7′b through the through-hole 62′ formed in the shielding wall 61′.
In the opening portion 6a′ of the housing 6′ is fitted a connector (illustration is omitted) with a cable to connect to a control device not shown. This allows the connection portions 7b′ of the connector 5′ and connection portions (illustration is omitted) of the counterpart connector to be connected, thereby enabling output signals of the switches 72′ to be transmitted from the switch device 100′ to the control device.
Furthermore, an upper surface 21′ of the upper case 2′ is provided with tubular portions 26′, each of which opens vertically to communicate with an inside of the case. The operation knob 81′ is attached to each of these tubular portions 26′ so as to cover an upper opening of the relevant tubular portion 26′. Each of the operation knob 81′ is operably exposed from an opening portion 91′ provided in the cover 9′.
In the above-described switch 100′, when rainwater coming in through a window forgotten to close, drinkable water spilled from a container or the like (hereinafter, collectively referred to as “water”) is poured on the cover 9′, the relevant water flows down to the upper surface 21′ of the upper case 2′ through gaps between the opening portions 91′ of the cover 9′ and the operation knobs 81′, and flows to the tubular portion 26′ side.
The water flowing to the tubular portion 26′ side, if an amount thereof is large, may go up through gaps between the operation knobs 81′ and the tubular portions 26′, and may come into the case 1′ through the openings of the tubular portions 26′. The water coming into the case 1′ will cause corrosion and a short circuit in the electronic components such as the printed circuit board 71′ and the switches 72′.
Therefore, a groove portion 28′ for drainage is provided in the vicinity of each of the tubular portions 26′ to drain the water flowing down to the upper surface of the upper case 2′ from the relevant groove portion 28′. The above-described groove portions 28′ extend, for example, in right and left directions (R and L directions) of the case 1′, and end portions on the side surface sides of the upper case 2′ are opened. Accordingly, the water drained from the end portions of the groove portions 28′ flows down on the side surfaces of the case 1′ to be drained outside.
Here, when each of the above-described groove portions 28′ is located above (in the U direction of) the connector 5′, the water drained from the relevant groove portion 28′ and flowing down on the side surface of the case 1′ can flow to the connector 5′ side along the side surface of the case 1′.
Furthermore, as a method for attaching the switch device, as shown in FIG. 17, the switch device is generally attached at an angle at which front and back directions F and B of the switch device 100′ is substantially parallel to a floor surface of the vehicle, that is, the ground.
However, in recent years, from a request from a user, convenience of the operation and the like, a method of attaching the switch device 100′ in a state where the front side thereof is inclined in the upper direction U at a predetermined angle (e.g., 20° to 30°) to the ground has begun to be employed (refer to FIG. 18).
Moreover, when the switch device 100′ is horizontally attached, the switch device 100′ is relatively inclined when the vehicle travels on a steep upslope.
In this manner, when the switch device 100′ is inclined at a predetermined angle to the horizontal direction, the water flowing down on the side surfaces of the case 1′ can flow to the connector 5′ side along the side surfaces of the case 1′, even in the case where the groove portions 28′ are not provided above (in the U direction of) the connector 5′.
The water flowing to the connector 5′ side will come into the connection portions 7′b from the opening portion 6a′ of the housing 6′, thereby causing corrosion and a short circuit inside the connector 5′.
On the other hand, in Japanese Patent Application Laid-Open Nos. 2007-97322, H9-204842, H8-212874, there have been proposed a switch device and the like in which means for preventing water from coming into a connector portion is taken.
For example, in the above-described Japanese Patent Application Laid-Open No. 2007-97322, a connector is included on a lower surface of a lower cover (a box body) of a relay block. In an inner bottom surface of this lower cover, an opening is formed. Moreover, a gap enabling water removal through the opening is assured between the lower cover and the connector. The water flowing into the lower cover is drained outside through the above-described opening and gap.
In Japanese Patent Application Laid-Open No. H9-204842, a connector is included in an end portion of a switch box. Moreover, in the switch box, there is provided a waterproof cover made up of eaves covering an upper part of the connector, an upper water stopping wall extending upwardly from a frontal edge of the eaves, and two side water stopping walls covering both sides of the connector. The water flowing onto an upper surface of the switch box is received by the eaves, and is then guided by the side water stopping walls and flows down along the side water stopping walls to be drained outside.
In Japanese Patent Application Laid-Open No. H8-212874, on a lower surface of a switch case, a connector is included. In this switch case, a hook formed in the connector is put into a snap fit hole formed in a case side surface, by which the connector is fixed to the case lower surface. Moreover, in a case upper surface provided with a switch knob, there is formed a water catching groove, and in the case side surface, a drainage port penetrating a deepest portion of the water catching groove, and a drainage guide that guides the water flowing out from the drainage port to cause the water to flow down. The water flowing onto the case upper surface is caught in the water catching groove, and is then drained by the drainage port and the drainage guide to a position deviating from the snap fit hole.
However, the structures described in Japanese Patent Application Laid-Open Nos. 2007-97322, H9-204842, H8-212874 are insufficient to prevent the water running along the side surfaces of the case from coming around into the connector from the opening portion of the connector, and more effective waterproof countermeasures are desired.