Patent Grant
7288734
1. Field of the Invention
The present invention relates to switches for a vehicle (hereinafter referred to as vehicle switches) that are incorporated mainly in a vehicle and used to detect whether a door thereof is opened or closed.
2. Background Art
It is widely applied to control turning on and off the lighting apparatuses in a vehicle cabin, by using a vehicle switch incorporated in the door part thereof according to opening and closing operation of the door. In many cases, such a vehicle switch is incorporated in a place exposed to water drops, such as rain, when the door is open; therefore, the vehicle switch is protected from water by a rubber cover or other parts. A description is provided of such a conventional vehicle switch in reference to
Operating body 35 made of an insulating resin is housed in inner case 32 so as to be vertically movable. Operating portion 35A at the top end of operating body 35 projects upwardly from through-hole 31A. Both ends of substantially U-shaped movable contact (hereinafter referred to as a contact) 36 that is made of metal and fitted into operating body 35 makes resilient contact with corresponding one of contacts 33 and 34. Contacts 33 and 34 are electrically coupled via contact 36. In this manner, a switch contact is formed.
Coil-like spring 37 is installed between the outer bottom face of operating body 35 and the inner bottom face of inner case 32 so as to slightly be contracted. Spring 37 urges operating body 35 upwardly. Elastic cover (hereinafter referred to as a cover) 38 is substantially shaped like a dome and made of a thin rubber. Cover 38 is attached onto the outer top face of outer case 31 by mounting plate 39 made of a metal plate. Covering through-hole 31A and operating body 35A, cover 38 prevents water or dust from entering into the switch from the gap between outer case 31 and operating body 35. In this manner, the vehicle switch is structured.
This vehicle switch is mounted on the chassis, for example, of a door part of a vehicle. Terminals 33A and 34A of contacts 33 and 34 projecting downwardly from the outer bottom face of inner case 32 are coupled to room lamps, for example, by leads (not shown) via electronic circuits (not shown) of the vehicle.
Next, a description is provided of the operation of this vehicle switch. Closing a door of the vehicle as shown in the sectional view of
In contrast, opening the door brings pressing portion 40 out of contact with cover 38, thus removing depression to operating body 35. For this reason, cover 38 is restored to the state of
However, used for water-proof and dust-proof cover 38 in the conventional vehicle switch is a rubber or other materials that has a large friction coefficient and thus does not slide easily. For this reason, when pressing portion 40 of a door is brought into not perpendicular but oblique contact with cover 38 as shown in
A vehicle switch of the present invention includes a case, an operating body, a switch contact, an elastic cover, and a sliding part. A through-hole is formed through the top face of the case. The top end of the operating body projects from the through-hole. The operating body is housed in the case vertically movable. The switch contact is brought into and out of electrical contact by vertical movement of the operating body. The elastic cover covers the through-hole of the case and the top end of the operating body. The sliding part that has a smaller friction coefficient than that of the elastic cover is provided in the top portion of the elastic cover. The sliding part covers at least the rim of the top portion of the elastic cover, or protrudes from the top face of the top portion and has an arc-shaped curved surface in the outer periphery of the upper rim thereof. With this structure, even when a pressing body, such as a door, is brought into oblique contact with the rim of the top portion of the elastic cover, the sliding part slides with respect to the pressing body, and thus elastically deforms the elastic cover in a normal state that is the same as the state in which the cover is pressed perpendicularly. Thus, breakage of the elastic cover is prevented.
Operating body 5 made of an insulating resin, such as polyacetal and nylon, is housed in inner case 2 vertically movable. Operating portion 5A at the top end of operating body 5 projects from through-hole 1A upwardly. In other words, operating body 5 is housed in the case lineally movable in one direction with one end thereof projecting from through-hole 1A.
Both ends of substantially U-shaped movable contact (hereinafter referred to as a contact) 6 that are fitted into operating body 5 and made of metal, such as cupper alloy, are in resilient contact with contacts 3 and 4. Contacts 3 and 4 are electrically coupled with each other via contact 6. In this manner, contacts 3, 4, and 6 form a switch contact to be brought into and out of electrical contact with one another by the movement of operating body 5.
Coil-like spring 7 made of a steel wire, for example, is installed between the outer bottom face of operating body 5 and the inner bottom face of inner case 2 so as to slightly be contracted. Spring 7 urges operating body 5 upwardly. Elastic cover (hereinafter referred to as a cover) 8 is substantially shaped like a dome made of thin rubber or elastomer. Cover 8 is attached onto the top face of outer case 1 by mounting plate 9 made of metal. Covering through-hole 1A and the top end of operating body 5A, cover 8 prevents water and dust from entering into the switch from the gap between outer case 1 and operating body 5.
Sliding part 8A shaped into substantially circular plate is formed integrally with top portion 8X on the top face of cover 8 therein so as to cover at least the rim of top portion 8X. Cover 8 comprises a non-planar contour. Sliding part 8A protrudes from a top face of top portion 8X of cover 8 and has a smaller friction coefficient than that of cover 8. Sliding part 8A follows the non-planar contour prior to sliding part 8A being pressed with respect to the case. Sliding part 8A is made of tetrafluoroethylene or other materials, which has a smaller friction coefficient than that of cover 8 and thus easily slides. In this manner, the vehicle switch is structured.
Next, a description is provided of steps of manufacturing cover 8 and sliding part 8A formed thereon with reference to the sectional views of
Next, as shown in
When rubber is used as the material of cover 8, a lump of rubber material may be placed on sliding part 8A and compression-molded by heated lower die 20A and upper die 20B to provide cover 8.
An adhesive can be applied to the face in which sliding part 8A is attached to top portion 8X to form sliding part 8A and top portion 8X integrally. By doing so, intimate contact therebetween is further enhanced.
The vehicle switch structured as above is mounted on the chassis, for example, of a door part of a vehicle. Terminals 3A and 4A of contacts 3 and 4 projecting downwardly from the outer bottom face of inner case 2 are coupled to room lamps or other apparatuses by leads (not shown) via electronic circuits (not shown) of the vehicle.
Closing the door of the vehicle brings pressing portion 10 of the door into contact with sliding part 8A as shown in a sectional view of
Sliding part 8A in contact with pressing portion 10 is made of tetrafluoroethylene or the like that has a smaller friction coefficient than that of rubber or the like and thus easily slides. The rim of top portion 8X is covered by sliding part 8A that has an outer periphery bent into substantially a U shape and an arc-shaped curved surface along the outer periphery of the upper rim thereof. With this structure, even when pressing portion 10 approaches top portion 8X obliquely, pressing portion 10 makes contact with the vicinity of the bent portion of sliding part 8A. At this time, sliding part 8A slides on the bottom face of pressing portion 10, thus elastically deforming cover 8 in a normal state that is the same as the state in which the cover is pressed perpendicularly.
In other words, when the upper right end of sliding part 8A is pressed obliquely from the upper right direction as shown in
Furthermore, it is preferable that sliding part 8A has an outer periphery bent into a substantially U shape and an arc-shaped curved surface along the outer periphery of the upper rim thereof so as to cover the rim of top portion 8X. In this structure, this arc-shaped curved-face rim allows sliding part 8A to slide more smoothly than a circular-plate-shaped sheet that has a small friction coefficient and an outer periphery of the upper rim shaped like a sharp edge and is attached onto top portion 8X, for example, when pressing portion 10 makes contact with sliding part 8A.
When cover 8 is elastically deformed in a normal shape that is the same as the shape in which cover 8 is perpendicularly pressed, operating body 5 moves downwardly, while contracting spring 7, as shown in
In contrast, opening the door brings pressing portion 10 out of contact with cover 8, removing depression to operating body 5. Thus, cover 8 is restored to the state of
As described above, the vehicle switch of
Incidentally, the piece of sliding part 8A may be produced as shown in
Next, a description is provided of another structure of the sliding part and the cover of this embodiment.
Sliding part 8B is made of an insulating resin that has a smaller friction coefficient than that of cover 8 and is more slidable than cover 8, such as acrylonitrile-butadiene-styrene (ABS) copolymer resin and polyoxymethylene. The outer periphery of the upper rim of sliding part 8B protruding from the top face of top portion 8Y has upper rim 8C having a substantially arc-shaped curved surface. The structures other than this portion are the same as those of the vehicle switch of
In similar to the structure of
The structure of
Furthermore, sliding part 8B that has upper rim 8C of a substantially arc-shaped curved surface along the outer periphery of the upper rim protrudes from the top face of top portion 8Y in the structure of
As described above, the structure of
The above description provides a structure in which sliding part 8B is fitted onto top portion 8Y on the top face of cover 8. However, sliding part 8B may be formed integrally with cover 8 by coinjection molding or other methods. Coinjection molding facilitates production of cover 8 and enhances the intimate contact between cover 8 and sliding part 8B.
Additionally, the above description provides a structure in which sliding part 8A or 8B is formed like a substantially circular-plate or disk shape. However, the sliding part may be formed into a substantially ring shape having a central opening. There are various kinds of methods of attaching the sliding part to the top portion, such as integral formation by coinjection molding, and attaching or press-fitting the sliding part separately formed of an insulating resin or other materials.
Further, the above description provides a structure in which substantially U-shaped contact 6 and thin-sheet-like contacts 3 and 4 form a switch contact. However, the present invention is applicable to switch contacts of various kinds of structures, such as opposing a rivet-like fixed contact to a movable contact with predetermined clearances provided therebetween.
As described above, for a vehicle switch of the present invention, breakage of the elastic cover thereof is prevented. This advantage can provide a securely water-proof and dust-proof vehicle switch. This switch is useful to detect whether the door of a vehicle is opened or closed, in addition to other purposes.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-318963 | Nov 2004 | JP | national |
| 2005-289791 | Oct 2005 | JP | national |
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| Number | Date | Country |
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| 2001-035294 | Feb 2001 | JP |
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| Number | Date | Country | |
|---|---|---|---|
| 20060090991 A1 | May 2006 | US |
