Fluid handling – Systems – Multi-way valve unit
Reexamination Certificate
2001-08-14
2002-11-12
Michalsky, Gerald A. (Department: 3753)
Fluid handling
Systems
Multi-way valve unit
C477S142000
Reexamination Certificate
active
06478050
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority of Korea patent Application No. 2000-87014, filed on Dec. 30, 2000.
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to a manual valve used in a hydraulic pressure control system for an automatic transmission.
(b) Description of the Related Art
Generally, a conventional automatic transmission for a vehicle includes a multi-stage gear shift mechanism connected to a torque converter, and a plurality of friction elements actuated by hydraulic pressure under control of a hydraulic pressure control system for selecting a gear stage of the gear shift mechanism.
In such automatic transmissions, the hydraulic pressure control system includes a pressure regulating means for controlling a level of hydraulic pressure generated by a hydraulic pump, manual/automatic shift control means for performing shift operation, hydraulic pressure control means for adjusting responsiveness and shift quality by smoothing shift operation, hydraulic pressure distributing means for distributing the pressure from the hydraulic pressure control means to appropriate friction elements, and damper clutch control means for controlling operation of a damper clutch of a torque converter.
The gear shift control is achieved by the friction elements being selectively and differently applied by hydraulic pressure from the distribution means and cooperation of on/off and duty control solenoid valves, such that a constitution and control method of a hydraulic control system depends on particular power trains adapted by car makers and how the power trains are controlled.
FIG. 1
shows a conventional hydraulic control system for an automatic transmission.
When a torque converter
2
is driven, a hydraulic pump
4
generates hydraulic pressure required for controlling the torque converter
2
and shift control and for lubrication. The hydraulic pressure generated by the hydraulic pump
4
is supplied to pressure regulating means, damper clutch control means, and reducing means, and to pressure control means via manual/automatic shift control means to be modulated to a shift control pressure. The shift control pressure controlled by the pressure control means is supplied to the friction elements as operating pressure via switching means and fail-safe means. The hydraulic pressure is directly supplied from the manual/automatic control means to N-R control means, and then to the friction elements.
Describing more in detail, the pressure regulating and damper clutch control means includes a regulator valve
6
for uniformly regulating hydraulic pressure generated by the hydraulic pump
4
, a torque converter control valve
8
for supplying the regulated hydraulic pressure to the torque converter
2
and for adjusting the regulated hydraulic pressure to be suitable for lubrication, a damper clutch control valve
10
for controlling a damper clutch to improve a power transmission efficiency of the torque converter
2
.
The reducing means comprises a reducing valve
12
for reducing hydraulic pressure to be lower than the line pressure. Part of the hydraulic pressure reduced by the reducing valve
12
is directed to the damper clutch control valve
10
and the regulator valve
6
as control pressure, and the rest is supplied to first, second and third pressure control valves
14
,
16
and
18
that are controlled by first, second and third solenoid valves S
1
, S
2
and S
3
, respectively.
The manual/automatic shift control means includes a manual valve
20
cooperating with a shift selector lever (not shown). The hydraulic pressure fed to the manual valve
20
is, in accordance with the operation of the shift selector lever, directed to the first, second and third pressure control valves
14
,
16
,
18
as control pressure, or directly to first and second switch valves
22
and
24
, the first and second fail-safe valves
26
and
28
, and the N-R control valve
30
as control pressure and operating pressure to be fed to the fiction elements.
In the above described hydraulic control system, when an engine is operating, line pressure of a certain degree is required for supplying fluid as lubricant to rotating elements regardless of the range that the manual valve
20
is in.
Furthermore, when the manual valve is displaced in a parking range P or a neutral range N, line pressure identical to or lower than that required for forward ranges D, 3, 2 and L is required to prepare for the shift operation into forward and reverse ranges. Line pressure required for the reverse range R is generally higher than that for the forward ranges.
However, since the shift range of the manual valve
20
is arranged in the order of P, R, N, D, 3, 2, and L, that is, since the reverse range R is arranged between the parking and neutral ranges P and N, it is practically difficult to satisfy the above requirements.
Accordingly, some hydraulic control systems have been designed such that no line pressure is formed in the parking range P. However, in these cases, when the engine is operated for a long time in the parking range P, rotating elements suffer a lack of lubrication since there is no line pressure.
Therefore, it has become a trend that line pressure is basically formed in the parking and neutral ranges P and N so as to supply lubricant to the rotating elements.
FIGS. 14
a
and
14
b
shows a conventional manual valve which is designed to form line pressure in the parking and neutral ranges P and N.
A valve body of a manual valve is provided with a first port
200
for receiving hydraulic pressure from a regulator valve, a second port
202
for supplying the hydraulic pressure fed through the first port
200
to parking and neutral range pressure lines, a third port
204
for supplying the hydraulic pressure fed through the first port
200
to drive, second, and low range pressure lines, fourth and fifth ports
206
and
208
for supplying hydraulic pressure fed through the first port
200
to a reverse range pressure line, and an exhaust port EX for exhausting the hydraulic pressure fed to the fourth and fifth ports
206
and
208
.
A valve spool
210
, being movably disposed in the valve body in accordance with the manipulation of the shift selector lever, includes a first land
214
formed proximate to a connector
212
, positioned between the second and third ports
202
and
204
in the parking range P, and positioned on one side of the third port
204
in other ranges R, N, D, 2 and L; a second land
216
for communicating the second or third port
202
or
204
with the first port
200
in all ranges except for the parking and reverse ranges P and R; and a third land
218
for communicating the first port
200
with the fourth and fifth ports
206
and
208
in the reverse range R.
Also, the valve spool
210
is further provided with an exhaust hole
220
formed from the connector
212
to the second land
216
, a first release opening
222
formed between the first and the second lands
214
and
216
in a vertical direction with respect to an axis of the valve spool
210
, and a second release opening
224
formed proximal to the connector
212
between the first land
214
and the connector
212
.
In the parking range P, the hydraulic pressure supplied to the manual valve through the first port
200
is directed to the second port
202
and the exhaust hole
220
through the first release opening
222
. In the reverse range R, the first port
200
communicates with the fourth and fifth ports
206
and
208
, and in the neutral range N, the first port
200
communicates with the second port
202
. In the forward ranges D, 2 and L, the first port
200
communicates with the second and third ports
202
and
204
.
In this conventional manual valve, since the hydraulic pressure fed from the hydraulic pump
4
is used for lubrication and hydraulic pressure for a parking and neutral range, there is no problem in lubricating the rotating members in the parking and neutral ranges P and N. However, since the hydraulic pressure is fed thr
Cho Jae-Ho
Jang Jae-Duk
Kim Tae-Kyun
Lee Chang-Wook
Lee Jin-Hee
Birch & Stewart Kolasch & Birch, LLP
Hyundai Motor Co.
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