Electricity: conductors and insulators – Boxes and housings
Reexamination Certificate
2000-11-09
2002-06-25
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Boxes and housings
C174S058000, C220S004020, C310S06800R
Reexamination Certificate
active
06410849
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The invention relates to the technical field of a wiper motor device applied to vehicles, such as automobiles and trucks.
2. Description of Related Art
Generally, in this type of a wiper motor device, there is a type in which an output shaft (wiper pivot axis) outputs motor drive via a reduction mechanism and a link mechanism, is disposed at a portion adjacent to a drive circuit portion while the drive circuit portion (circuit board, etc.) that incorporates circuits to execute various types of wiping actions, such as intermittent wiping, etc., is disposed inside a body sheet material (glass plate and body outer plate, etc.,). With such a wiper motor device, the tip end portion of the output shaft is caused to pass through an attaching hole opened in the body plate material to protrude outside the body, and a wiper arm is connected to the protruded tip end portion thereof. In such a device, the drive circuit portion is accommodated in an accommodation casing shielded with a cover in order to prevent foreign substances from adhering thereto. In this case, the cover is fixed at the accommodation casing by engaging engagement claws projecting from the accommodation casing into engagement holes opened in the cover.
In such a wiper motor device, it is necessary to prevent water from invading the body interior through the attaching through holes of the output shaft. Therefore, conventionally, a waterproof member, such as a grommet, etc., is attached to the attaching through holes of the output shaft, thereby preventing water from invading by using the waterproof member.
However, even though a waterproof member, such as a grommet, is attached, there are cases where water invades the body interior through a slight gap at the attaching through holes of the output shaft at the time of heavy rain or washing with high pressure water. And, for example, in the case where the drive circuit portion is disposed downward of the output shaft, there is a fear that the water, invading the body interior, flows into the drive circuit portion side and further invades the accommodation casing between the cover and accommodation casing or through the engagement holes. Therefore, if water or humidity that thus invaded the accommodation casing adheres to the drive circuit portion, it becomes a cause of failure of the drive circuit portion, which constitutes a problem.
SUMMARY OF THE INVENTION
The invention was developed to solve the problems and the shortcomings as described in the abovementioned situations. The invention comprises a drip-proof structure for a wiper motor device in which a drive circuit portion of a wiper motor is disposed adjacent to an output shaft of the wiper motor such that when a cover is provided to shield an upper opening of an accommodation casing for accommodating the drive circuit portion, an extension portion fitted to the outer circumference of the output shaft in a drip-proof state is formed on the cover and extends therefrom.
By this structure, even though water may invade along the output shaft, the water will flow on the cover from the output shaft via the extension portion, whereby it is possible to prevent water from invading the accommodation casing, and the drive circuit portion can be effectively protected from water.
In such a structure, a cylindrical portion fitted to the outer circumference of the output shaft is formed at the extension portion of the cover. By fitting the base end of the waterproof cap attached to the output shaft to the outer circumference of the tip end side of the corresponding cylindrical portion, it is possible to fit the extension portion to the output shaft in a drip-proof state.
Also, because a guide rib is formed at the upper surface portion of the cover, which guides water flowing on the upper surface of the cover to prevent the water from reaching the fixing portion that fixes the accommodation casing and cover, it is possible to prevent water from invading the accommodation casing from the fixing portion. Therefore, an excellent drip-proof structure can be obtained.
REFERENCES:
patent: 4487328 (1984-12-01), Wilcox et al.
patent: 5177325 (1993-01-01), Giammanco
patent: 6005188 (1999-12-01), Teichler et al.
patent: 6285101 (2001-09-01), Kazama et al.
patent: 2192315 (1988-01-01), None
patent: U-6-25063 (1994-04-01), None
Amagasa Toshiyuki
Okabe Hiroji
Mitsuba Corporation
Oliff & Berridg,e PLC
Patel Dhiru R.
Reichard Dean A.
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