Pumps – Motor driven – Including means utilizing pump fluid for augmenting cooling,...
Reexamination Certificate
1999-12-13
2001-07-03
Walberg, Teresa (Department: 3742)
Pumps
Motor driven
Including means utilizing pump fluid for augmenting cooling,...
C417S360000, C417S423140, C417S423100
Reexamination Certificate
active
06254360
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a washer pump for a washer device that sprays cleaning liquid to the windshield of a vehicle. More specifically, the present invention relates to a structure that protects the motor of the washer pump from water.
A typical washer device for vehicles includes a tank for storing cleaning liquid and a washer pump for pumping the cleaning liquid from the tank to a washer nozzle. The washer pump has a housing including a motor chamber and a pump chamber. The motor chamber accommodates a direct current motor. The pump chamber includes an impeller. The motor has an output shaft that extends into the pump chamber. The impeller is fixed to the distal end of the output shaft. A seal is located about the output shaft to seal the motor chamber from the pump chamber. The motor rotates the impeller, which pumps the cleaning liquid from the tank to the washer nozzle.
The temperature of the motor increases when operating and decreases when stopped. Air in the motor chamber expands or contracts in accordance with the changes of temperature of the motor. When the motor chamber is sealed, contraction of air in the motor chamber draws the cleaning liquid from the pump chamber to the motor chamber between the output shaft and the seal. This may cause the motor to corrode and malfunction.
To solve the above problems, Japanese Unexamined Utility Model Publication No. 2-49657 describes a washer pump having an air hole open to the atmosphere. As shown in
FIG. 7
, a cylindrical washer pump
60
is attached to a side of a tank
63
, which stores window cleaning liquid. A housing
64
of the pump
60
includes a motor case
70
and a pump case
67
attached to the lower part of the motor case
70
. A motor chamber
66
for accommodating a motor
61
is formed in the motor case
70
. A pump chamber
65
for accommodating an impeller
73
is formed between the motor case
70
and the pump case
67
.
An output shaft
62
of the motor
61
extends vertically through the motor case
70
to the inside of the pump chamber
65
. A seal
72
is located about the output shaft
62
to seal the motor chamber
66
from the pump chamber
65
. The motor case
70
has an inlet
68
for introducing cleaning liquid from the tank
63
to the pump chamber
65
. The pump case
67
has an outlet
69
for discharging cleaning liquid from the pump chamber
65
. An air hole
71
connects the motor chamber
66
to the outside of the housing
64
near the lower end of the motor case
70
below the motor
61
.
The air hole
71
prevents cleaning liquid from being drawn from the pump chamber
65
to the motor chamber
66
. Even if cleaning water enters the motor chamber
64
due to a defect of the seal
72
, the air hole
71
drains the cleaning liquid to the exterior of the motor chamber
66
and prevents the cleaning liquid from contacting the motor
61
.
However, if the washer pump
60
is splashed by water while the vehicle runs through standing water, water may get in the motor chamber
66
through the air hole
71
. This may cause a malfunction of the motor
61
and thus should be avoided.
Condensation of water may also occur due to temperature changes of the motor
61
. The air hole
71
is not suitable for removing water condensation.
Further, most of the washer pump
60
is located outside the tank
63
. This complicates the attachment of the washer pump
60
to the tank
63
and causes the washer pump
60
to be unstable.
It is possible to form a recess on a side wall of the tank
63
and fix the washer pump
60
in the recess with fasteners. However, this complicates the shape of the tank
63
and the installation of the pump
60
. Also, this limits the shape of the tank
63
, which complicates the tank
63
installation.
As shown in
FIG. 8
, Japanese Unexamined Patent Publication 4-129863 describes a washer pump
80
, half of which is received in and fixed to a tank
81
. A housing
82
of the pump
80
extends horizontally. An inlet
84
connected to a pump chamber
83
is formed in the distal end of the housing
80
, which is located in the tank
81
. A motor chamber is horizontally spaced from the pump chamber
83
. The motor
86
rotates an impeller
87
, which causes cleaning liquid in the tank
81
to flow through the inlet
84
, a passage
88
in the housing
82
, and through an outlet (not shown).
The pump
80
is received in and firmly fixed to the tank
81
without a complicated installation structure. Therefore, the shape of the tank
81
is simple and not limited.
However, since the motor chamber
85
is horizontally spaced from the pump chamber
83
, if cleaning water in the pump chamber
83
enters the motor chamber
85
, the horizontal motor
86
in the motor chamber
85
is immediately exposed to the leaked cleaning liquid. Even if an air hole that can drain the leaked cleaning liquid is provided in the motor chamber
85
, the leaked cleaning liquid from the pump chamber will most likely contact the motor
86
before being drained. Therefore, in the pump
80
of
FIG. 8
, an air hole alone will not prevent the motor
86
from contacting cleaning liquid.
SUMMARY OF THE INVENTION
An objective of the present invention is to provide a washer pump that protects its motor from water and prevents motor malfunctions caused by water.
To achieve the above objective, the present invention provides a pump structured as follows. A housing includes a motor chamber. A motor is accommodated in the motor chamber. A motor-driven impeller draws in a liquid and pumps the liquid. An internal passage is formed in the motor for connecting the interior of the motor to the motor chamber. The internal passage is arranged to lead liquid from the interior of the motor to the motor chamber. A drain structure is formed in the housing radially outward of the internal passage to connect the motor chamber to the exterior of the housing. The drain structure is arranged to guide liquid from the motor chamber to the exterior of the housing. The drain structure includes passages that extend in at least two different directions.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
REFERENCES:
patent: 6053708 (2000-04-01), Nishikawa
patent: 6109891 (2000-08-01), Sato
patent: 2-49657 (1990-04-01), None
patent: 04129863 (1992-04-01), None
patent: 05162618 (1993-06-01), None
Asmo Co. Ltd.
Nath&Associates PLLC
Novick Harold L.
Patel Vinod D
Walberg Teresa
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