Planetary gear transmission systems or components – Fluid drive or control of planetary gearing – Fluid controlled mechanical clutch or brake
Reexamination Certificate
2002-11-25
2004-05-25
Lorence, Richard M. (Department: 3681)
Planetary gear transmission systems or components
Fluid drive or control of planetary gearing
Fluid controlled mechanical clutch or brake
C475S210000, C477S045000, C192S003580
Reexamination Certificate
active
06739998
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a hydraulic controller for an automatic transmission mounted on a vehicle or the like, and more particularly to a hydraulic controller capable of fixing a control valve utilizing a switching valve when a hydraulic pressure output from the control valve is not used.
2. Description of Related Art
FIG. 3
shows a hydraulic circuit of a conventional hydraulic controller
100
for an automatic transmission, and
FIG. 4
is a schematic diagram showing a part of the hydraulic circuit shown in FIG.
3
.
In
FIG. 3
, reference numeral
87
denotes an oil temperature sensor and reference numeral
89
denotes a pressure sensor.
A linear solenoid valve SLT outputs a signal pressure (SLT pressure) Pslt, based on a throttle opening or the like, to oil passages a
1
, a
2
. A clutch modulator valve
76
adjusts a line pressure PL from a hydraulic pressure generating source (not shown) and outputs it as a range pressure (clutch modulator pressure) Pcmod to oil passages c
2
, c
3
and c
5
through oil passages c
1
, c
4
and a strainer
85
. A solenoid modulator valve
83
reduces the range pressure of the oil passage c
5
by a predetermined amount and outputs it as a solenoid modulator pressure to oil passages g
1
, g
2
and solenoid valves SOL, SOL
2
. A secondary sheave control valve
73
adjusts the line pressure PL to a secondary sheave pressure and outputs it to a hydraulic actuator for a secondary sheave
35
of a continuously variable transmission mechanism, based on the solenoid modulator pressure from the oil passage g
2
and the SLT pressure Pslt from the oil passage a
1
.
Also, as shown in
FIGS. 3 and 4
, a garage shift control valve
77
adjusts the range pressure from an oil passage c
4
, based on the SLT pressure Pslt from the oil passage a
2
, to provide a direct control pressure through an oil passage k
1
for directly controlling the engagement state of a clutch C
1
or a brake B
1
. A garage shift valve
79
switches between the range pressure Pcmod from the oil passage c
2
and direct control pressure from the oil passage k
1
, based on the signal pressures Psol
1
, Psol
2
of the solenoid valves SOL, SOL
2
, for output to the oil passage
1
. A manual shift valve
75
which is moved by operation of a shift lever (not shown) and outputs the range pressure or the direct control pressure of the oil passage
1
to a hydraulic servo
30
of the clutch C
1
through an oil passage d in drive (D range) and to a hydraulic servo
31
of the brake B
1
through an oil passage e in reverse (R range).
A feedback pressure is input through the oil passage k
2
, while the direct control pressure is output to the oil passage k
1
from the garage shift control valve
77
, counter to the SLT pressure Pslt from the oil passage a
2
in the valve
77
, to provide feedback control of the direct control pressure. The feedback pressure is input into a clutch modulator valve
76
, a solenoid modulator valve
83
and a secondary sheave control valve
73
, as well as the garage shift control valve
77
.
In the above hydraulic controller
100
, a shift lever (not shown) may be positioned so that direct control pressure from the garage shift control valve
77
is supplied to a hydraulic servo
30
of the clutch C
1
or to a hydraulic servo
31
of the brake B
1
through a garage shift valve
79
, to control the engagement state of the clutch C
1
or the brake B
1
. When the vehicle starts to run, the garage shift valve
79
is switched to supply a range pressure Pcmod from the clutch modulator valve
76
to the hydraulic servo
30
of the clutch C
1
or to the hydraulic servo
31
of the brake B
1
, to bring the clutch C
1
or the brake B
1
into a completely engaged state.
However, as shown in
FIG. 3
, even when the range pressure Pcmod of the clutch modulator valve
76
is supplied to the clutch C
1
or the brake B
1
, the garage shift control valve
77
is simultaneously controlled by the linear solenoid valve SLT through an oil passage a
2
, since the linear solenoid valve SLT controls the secondary sheave control valve
73
and a secondary sheave
35
of a continuously variable transmission mechanism. During such control the range pressure Pcmod supplied from the clutch modulator valve
76
through an oil passage c
4
is repeatedly adjusted based on the SLT pressure of the linear solenoid valve SLT, output to an oil passage k
1
, feedback-controlled through an oil passage k
2
, and drained from the drain port EX to a low hydraulic pressure.
Even though output of the garage shift control valve
77
is shut off by the garage shift valve
79
, and pressure adjustment of the garage shift control valve
77
is not required, oil supplied from an oil pump (not shown) through the clutch modulator valve
76
and the oil passage c
4
is unnecessarily drained to the drain port EX, which increases oil consumption in the hydraulic controller
100
, and results in reduction of fuel economy due to upsizing of the oil pump or decreased efficiency of the oil pump.
SUMMARY OF THE PRESENT INVENTION
The present invention provides a hydraulic controller for an automatic transmission which feedback-controls a first control valve through an oil passage when a switching valve outputs a hydraulic pressure output from the first control valve, and fixes the first control valve through that same oil passage when the switching valve outputs a hydraulic pressure of a hydraulic pressure generating source.
More specifically, the present invention provides a hydraulic controller for an automatic transmission which includes a hydraulic pressure generating source which outputs a first hydraulic pressure, a solenoid valve which outputs a signal pressure, a first control valve, and a switching valve. The first control valve includes a first oil chamber and a second oil chamber, arranged opposed to the first oil chamber. The signal pressure of the solenoid valve is received into the first oil chamber, and the first control valve adjusts the first hydraulic pressure of the hydraulic pressure generating source, in accordance with the signal pressure, and outputs the adjusted pressure as a second hydraulic pressure.
The switching valve receives the first and second hydraulic pressures and switches between and outputs one of these received hydraulic pressures, with the output of the switching valve passing through an oil passage into the second oil chamber of the first control valve.
When the switching valve outputs the second hydraulic pressure from the first control valve, the hydraulic controller utilizes that second (adjusted) hydraulic pressure for feedback control by supplying it to the second oil chamber of the first control valve. On the other hand, when the switching valve outputs the first hydraulic pressure (for example, Pcmod) from the hydraulic pressure generating source, the hydraulic controller for an automatic transmission supplies that first hydraulic pressure (for example, Pemod) to the second oil chamber to fix the first control valve.
Therefore, the hydraulic controller according to the present invention includes an oil passage which supplies the output of the switching valve to the second oil chamber of the first control valve. When the switching valve outputs the second hydraulic pressure from the first control valve, the hydraulic controller routes that second (adjusted) hydraulic pressure to the second oil chamber for feedback-control of the first control valve, and when the switching valve outputs the first hydraulic pressure of the hydraulic pressure generating source, the hydraulic controller routes that first hydraulic pressure of the hydraulic pressure generating source to the second oil chamber to fix the first control valve. Therefore, when the second hydraulic pressure output from the first control valve is used, a feedback-control is established, and when the first hydraulic pressure output from the first control valve is not used, the first control valve can be fixed. This prevents unnecessary oil drainage without adjustin
Habuchi Ryoji
Iwata Akihito
Tanaka Hiroshi
Tokunaga Junichi
Aisin AW Co. Ltd.
Lorence Richard M.
Lorusso, Loud & Kelly
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