Power window switch circuit

Details Power window switch circuit Power window switch circuit

2002-02-01

2004-02-10

Nappi, Robert (Department: 2837)

Electricity: motive power systems

Automatic and/or with time-delay means

C318S643000, C049S139000

Reexamination Certificate

active

06690131

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a power window switch circuit, and more particularly, it relates to a power window switch circuit having a drive motor, a relay, a switch and the like for raising and lowering a window glass.
BRIEF SUMMARY OF THE INVENTION
In general, a vehicle has a power window apparatus for opening and closing a window glass of a side door and the like, and the power window apparatus includes an UP switch (raising switch) and a DOWN switch (lowering switch) manually operated for raising and lowering the window glass.
FIG. 1
schematically shows an electric circuit of a power window switch circuit
10
in a conventional power window apparatus. The power window switch circuit
10
includes a DOWN switch
28
, an UP switch
29
, an automatic switch
30
, a control circuit
12
, a drive circuit
20
, and a drive motor M which is preferably a DC motor for raising and lowering a window glass. The drive circuit
20
includes a first relay
22
, a second relay
24
, and transistors TR
1
to TR
3
. The DOWN switch
28
and the UP switch
29
are used, for example, as a tumbler two-stepped click type switch. The DOWN switch
28
has a first knob (hereinafter referred to as “the DOWN side knob”), and a second knob (hereinafter referred to as “the UP side knob”). When the DOWN side knob is pressed by one step, a movable contact
31
of the DOWN switch
28
is connected to a fixed contact DN. When the UP side knob is pressed by one step, a movable contact
32
of the UP switch
29
is connected to a fixed contact UP. When the DOWN side knob is pressed by two steps, the DOWN switch
28
and the automatic switch
30
are both turned on. Moreover, when the UP side knob is pressed by two steps, the UP switch
29
and the automatic switch
30
are both turned on. In the automatic operation, after the knob is pressed by two steps, the DOWN switch
28
or the UP switch
29
is turned off but the automatic switch
30
is maintained in ON state for a predetermined period of time.
When the automatic switch
30
and the DOWN switch
28
are turned on, the control circuit
12
continues to supply a high (H) level relay drive signal to the base of the transistor TR
3
even after the DOWN switch
28
is turned off, until the window glass reaches a completely open position, and supplies an ON signal to the base of the transistor TR
1
, thereby turning on the transistors TR
1
and TR
3
. This supplies excitation current to the relay coil
21
of the first relay
22
. When the relay coil
21
is excited, the movable contact
25
c
of the relay contact
25
is switched from a ground side fixed contact
25
a
to a power supply side fixed contact
25
b
, and the drive motor M is supplied with the drive current and rotated in normal direction. The drive motor M drives a wire-type or arm-type regulator (not shown) so as to lower the window glass. When the window glass reaches the completely open position, a completely open position limit switch (not depicted) begins to operate. In response to this switch operation, the control circuit
12
stops drive of the drive motor M by the relay drive signal and maintains the window glass at the completely open position.
When the automatic switch
30
and the UP switch
29
are turned on, the control circuit
12
continues to supply a high (H) level relay drive signal to the base of the transistor TR
2
even after the UP switch
29
is turned off, until the window glass reaches a completely closed position, and supplies an ON signal to the base of the transistor TR
1
, thereby turning on the transistors TR
1
and TR
2
. This supplies excitation current to the relay coil
23
of the second relay
24
. When the relay coil
23
is excited, the movable contact
26
c
of the relay contact
26
is switched from a ground side fixed contact
26
a
to a power supply side fixed contact
26
b
, and the drive motor M is rotated in reverse direction. The drive motor M drives the regulator (not shown) so as to raise the window glass. When the window glass reaches the completely closed position, a completely closed position limit switch (not shown) begins to operate. In response to this switch operation, the control circuit
12
stops drive of the drive motor M by the relay drive signal and maintains the window glass at the completely closed position.
When the DOWN side knob is operated to turn on the DOWN switch
28
, the control circuit
12
supplies a high (H) level relay drive signal to the base of the transistor TR
3
and supplies the ON signal to the base of the transistor TR
1
, thereby turning on the transistors TR
1
and TR
3
. Accordingly, while the DOWN switch
28
is in ON state, excitation current is supplied to the relay coil
21
and drive motor M is rotated in the normal direction, thereby lowering the window glass.
When the UP side knob is operated to turn on the UP switch
29
, the control circuit
12
supplies the high (H) level relay drive signal to the base of the transistor TR
2
and supplies the ON signal to the base of the transistor TR
1
, thereby turning on the transistors TR
1
and TR
2
. Accordingly, while the UP switch
29
is in ON state, excitation current is supplied to the relay coil
23
and drive motor M is rotated in the reverse direction, thereby raising the window glass.
When the first relay
22
, the second relay
24
, and the control circuit
12
are soaked by an electrolyte liquid such as rain, leak resistance R
11
to R
15
may be caused as shown by dotted lines in FIG.
1
.
For example, even if the DOWN switch
28
is turned off and the control circuit
12
does not supply the ON signal and the H level relay drive signal to the transistors TR
1
and TR
3
, respectively, the transistors TR
1
and TR
3
are turned on by the leak resistance R
11
and R
13
. This excites the relay coil
21
, and the movable contact
25
c
is connected to the power supply side fixed contact
25
b
, which rotates the drive motor M in the normal direction and unintentionally lowers the window glass.
Moreover, even if the UP switch
29
is turned off and the control circuit
12
does not supply the ON signal and the H level relay drive signal to the transistors TR
1
and TR
2
, respectively, the transistors TR
1
and TR
2
are turned on by the leak resistance R
11
and R
12
. This excites the relay coil
23
, and the movable contact
26
c
is connected to the power supply side fixed contact
26
b
, which rotates the drive motor M in the reverse direction and unintentionally raises the window glass.
Furthermore, even if the transistor TR
3
is in OFF state, generation of leak resistance R
11
and R
15
may excite the relay coil
21
, which in turn rotates the drive motor M in the normal direction to lower the window glass unintentionally. Furthermore, even if the transistor TR
2
is in OFF state, generation of leak resistance R
11
and R
14
may excite the relay coil
23
, which in turn rotates the drive motor M in the reverse direction to raise the window glass unintentionally.
When the leak resistance R
11
to R
13
are generated, the transistors TR
1
to TR
3
are turned on, the relay coils
21
and
23
are excited, and the movable contacts
25
c
and
26
c
are connected to the power supply side fixed contacts
25
b
and
26
b
, respectively. In this case, identical voltage is applied to both the terminals of the drive motor M. Accordingly, even if the DOWN side knob or the UP side knob is operated, the drive motor M is not driven and the window glass is not raised or lowered.
When the leak resistance R
11
, R
14
, and R
15
are generated, the transistor TR
1
is turned on by the leak resistance R
11
, the relay coils
21
and
23
are excited, and identical voltage is applied to both the terminals of the drive motor M. Accordingly, even if the DOWN side knob or the UP side knob is operated in this state, the drive motor M is not driven and the window glass is not raised or lowered.
As has been described above, depending on the position where leak resistance is generated, four possible states should be considered: (a)

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