KR0180423B1 - Hydraulic control system of a/t - Google Patents

Abstract

In case of failure of the transmission control unit during operation, the fail safe function can secure the stability, thereby improving the reliability. In addition, by setting the second speed to two modes, the shift shock is reduced during normal shifting, The present invention provides a hydraulic control system for an automatic transmission for a vehicle which can improve the performance of the automatic transmission. Pressure regulating means for regulating the hydraulic pressure generated from the oil pump; A manual and automatic control means for forming a shift mode; A hydraulic control means for controlling the transmission feeling and responsiveness to form a smooth transmission mode when shifting; A damper clutch control means for operating the damper clutch of the torque converter; Second, third, fourth, and fifth friction elements acting as input and reaction force elements at each gear stage; In the hydraulic pressure distributing means, the hydraulic pressure distributing means includes: a port for receiving a control pressure from the timing control conduit connected to the first speed line to the right end; A port to which the first pressure control valve control pressure of the hydraulic control means is supplied; A second hydraulic pressure port for receiving the hydraulic pressure from the second and third branch passages of the second and third hydraulic passages of the shift control valve; And a second solenoid valve connected to the first solenoid valve and the second solenoid valve, wherein the first solenoid valve and the second solenoid valve are connected to the first solenoid valve and the second solenoid valve, respectively. Three ports in communication with the control switch valve; A port connected to the second speed and the shift control valve; Side chamber of the second friction element while being controlled by the hydraulic pressure supplied to the first friction element and the second-speed pressure while holding the port for supplying the hydraulic pressure supplied from the control switch valve to the operating- A fail-safe valve for controlling the discharge pressure to be supplied to the discharge port; Speed control of the solenoid valve for controlling the control switch valve, the third-speed pressure is supplied to the pressure regulating valve of the pressure regulating means, And a line-pressure varying means comprising a high-low pressure valve for varying the pressure of the hydraulic pressure control valve.

Description

Hydraulic control system of automatic transmission for vehicle

The present invention relates to a hydraulic control system applied to an automatic transmission for a vehicle.

For example, a vehicular automatic transmission includes a torque converter and a multi-stage transmission mechanism connected to the torque converter. The automatic transmission includes a hydraulic operation friction member for selecting one of gear positions of the gear mechanism of the transmission mechanism according to the running state of the vehicle Element.

The hydraulic control system of the vehicular automatic transmission performs a function of automatically selecting an appropriate shift according to the running condition of the vehicle by selecting the friction element through the control valve and operating the hydraulic pressure generated from the oil pump.

The hydraulic control system includes a pressure regulating means for regulating the hydraulic pressure generated by the oil pump, a manual and automatic speed change control means for forming a speed change mode, A hydraulic control means for adjusting the transmission feeling and responsiveness to form a smooth shift mode, a damper clutch control means for operating the damper clutch of the torque converter, and a hydraulic pressure distributing means for distributing a suitable hydraulic pressure supply to each friction element.

Accordingly, in this hydraulic control system, the hydraulic pressure distribution of the hydraulic pressure distributing means is changed by the solenoid valves which are turned on / off by the transmission control unit and the solenoid valves which are controlled by duty, so that the operation of the friction element is selected, .

However, in the above-described hydraulic control system, when the transmission control unit can not be operated, an interlock phenomenon may occur in the planetary gear set due to a malfunction of the friction element when the hold is performed in the third speed. The breakage of the automatic transmission can not be avoided and the reliability of the automatic transmission is deteriorated.

Accordingly, there is a need for a means for preventing the occurrence of interlocks of the planetary gear set with a fail-safe function more effective at the time of the third-speed hold due to the failure of the transmission control unit.

The 4-2 kick-down skid transmission is preferentially required to respond to the shock rather than the shifting shock. Since the normal 3-2 shifting and the 4-2 skip shifting have the same second speed mode, there is a problem that the sub-band is released after shifting have.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a safety safety function, 3-2 Downshift and 4-2 kick down After a skip shift, two speeds are set to two modes to make the solenoid valve operation different after the 4-2 shift, so that a vehicle automatic transmission The hydraulic control system of the present invention.

In order to achieve the above object, the present invention provides an oil pump comprising: a pressure regulating means for regulating a hydraulic pressure generated from an oil pump; A manual and automatic control means for forming a shift mode; A hydraulic control means for controlling the transmission feeling and responsiveness to form a smooth transmission mode when shifting; A damper clutch control means for operating the damper clutch of the torque converter; Second, third, fourth, and fifth friction elements acting as input and reaction force elements at each gear stage;

The hydraulic pressure distributing means includes a port for receiving a control pressure from the timing control line connected to the first speed line to the right end; A port to which the first pressure control valve control pressure of the hydraulic control means is supplied; A second port of the shift control valve and a port respectively receiving hydraulic pressure from the second and third branch passages of the third and fourth passages; And a second solenoid valve connected to the first solenoid valve and the second solenoid valve, wherein the first solenoid valve and the second solenoid valve are connected to the first solenoid valve and the second solenoid valve, respectively.

Three ports in communication with the control switch valve; A port connected to the second speed line of the shift control valve; Side chamber of the second friction element while being controlled by the hydraulic pressure supplied to the first friction element and the second-speed pressure while holding the port for supplying the hydraulic pressure supplied from the control switch valve to the operating- A fail-safe valve for controlling the discharge pressure to be supplied to the discharge port; Further comprising:

Speed control of the solenoid valve for controlling the control switch valve, the third-speed pressure is supplied to the pressure regulating valve of the pressure regulating means to change the line pressure. And a line-pressure varying means including a high-low pressure valve for controlling the hydraulic pressure of the vehicle.

In the branch pipe of the third-speed pipeline communicating with the control switch valve, a circulation pipe is formed at a distal end of the branch pipe to form an orifice, and a check valve is formed on the branch pipe to cut off hydraulic pressure supplied to the control switch valve And a hydraulic control system for an automatic transmission for a vehicle.

And a branch pipe communicating with the orifice and the check valve at an inlet of the check valve and having a distal end communicating with a port through which the third-speed pressure can be supplied to the fail-safe valve selectively via the control switch valve And a hydraulic control system for a vehicle.

In this case, the fail-safe valve is connected to the port at which the third-speed pressure via the control switch valve is formed at the rightmost end, and the second-speed channel is connected to the left port of the port, .

FIG. 1 is a view showing a hydraulic flow state in a neutral (N) range in a hydraulic control system according to the present invention; FIG.

FIG. 2 is a view showing a hydraulic flow state when a manual shift from a neutral (N) range to a reverse (R) is performed in the hydraulic control system according to the present invention.

FIG. 3 is a view showing a hydraulic flow state in the first running (D) range in the hydraulic control system according to the present invention; FIG.

FIG. 4 is a view showing a hydraulic flow state during a running (D) range 1 → 2 upshift in the hydraulic control system according to the present invention;

FIG. 5 is a view showing a hydraulic flow state in the second running (D) range in the hydraulic control system according to the present invention; FIG.

FIG. 6 is a view showing a hydraulic flow state at the time of traveling (D) range 2 → 3 upshift in the hydraulic control system according to the present invention;

FIG. 7 is a view showing a hydraulic flow state in the third running (D) range in the hydraulic control system according to the present invention; FIG.

FIG. 8 is a view showing a hydraulic flow state at the time of traveling (D) range 3 → 4 upshift in the hydraulic control system according to the present invention; FIG.

FIG. 9 is a view showing a hydraulic flow state in the fourth running (D) range in the hydraulic control system according to the present invention; FIG.

FIG. 10 is a view showing a hydraulic flow state at the time of the downshift (D) range 4 → 3 in the hydraulic pressure control system according to the present invention; FIG.

FIG. 11 is a view showing a hydraulic flow state at the time of a downshift (D) range 3 → 2 in a hydraulic control system according to the present invention; FIG.

FIG. 12 is a view showing a hydraulic flow state at the time of a downshift (D) range 2 → 1 in a hydraulic control system according to the present invention; FIG.

FIG. 13 is a view showing a hydraulic flow state at the time of traveling (D) range 4 → 2 kick down skip shift in the hydraulic control system according to the present invention; FIG.

FIG. 14 is a view showing a hydraulic flow state at the time of 4 → 3 fail-safe. FIG.

FIG. 15 is a view showing a hydraulic pressure state at the time of 2? 3 fail-safe. FIG.

FIG. 1 is a diagram showing a hydraulic control system according to the present invention, showing a state in which the select lever is in a neutral (N) range.

A hydraulic control system according to the present invention comprises a torque converter (2) for receiving torque from an engine and transmitting torque to the transmission side, an oil (2) for generating oil necessary for the torque converter and gear range control, And a pump 4.

A pressure regulating valve 8 for regulating the pressure of the oil flowing along the conduit to a constant pressure is provided in the conduit 6 through which the hydraulic pressure generated from the oil pump 4 flows and a torque regulating valve 8 for constantly controlling the pressure of the torque converter and the lubricating oil The converter control valve 10 and the damper clutch control valves 12 for increasing the power transmission efficiency of the torque converter are connected to constitute the pressure regulating means and the damper clutch controlling means.

A part of the oil generated from the oil pump 4 is supplied to the oil pump 4 through a relief valve 14 for maintaining a constant lower pressure than the line pressure, And constitutes a flow path which can be supplied to the manual valve 16.

The constant hydraulic pressure reduced by the reducing valve 14 is supplied to the first pressure control valve 18 and the second pressure control valve 20 to constitute hydraulic control means which can be used as the speed change stage control pressure.

A part of the hydraulic pressure supplied to the first and second pressure control valves 18 and 20 may be used as a control pressure of the NR control valve 22 for reducing a shift shock when the mode is changed from a neutral range to a reverse range. .

The first solenoid valve S1 and the second solenoid valve S2 (not shown), which are on / off-controlled by the transmission control unit, are connected to the line 24 through which hydraulic pressure flows when the manual valve 16 is in the running (D) The shift control valve 26 for switching the oil passage is communicated with the manual valve 16 to constitute the manual and automatic shift control means.

The second shift control valve 26 is connected to the second speed line 28, the third speed line 30 and the fourth speed line 32 and is controlled by the shift control valves of the hydraulic pressure distributing means So that the hydraulic pressure can be supplied.

The first conduit 34 is branched on the conduit 24 to supply the line pressure to the first and second pressure control valves 18 and 20. The first and second pressure control valves 18 ) 20 is configured to be capable of switching the flow path by the third and fourth solenoid valves S3 and S4 so that the first pressure control valve 18 can supply the control pressure to the friction element during the shift control, The second pressure control valve (20) is formed with a passage so as to supply drive pressure to the first friction element (C1) acting as an input element at first speed.

The second-speed line 28 of the shift control valve 26 is supplied to the left end port of the 1-2 shift valve 36 to control the valve, and the control switch valve 38 and the fail- And the hydraulic pressure supplied to the control switch valve 38 is supplied to the operation side chamber h1 of the second friction element C2 via the fail safe valve 40 under the control of the valve And the operating pressure is supplied.

The third branch conduit 30 branches to two pipelines 42 and 44 and is supplied to the left end port of the 2-3 / 4-3 shift valve 46 as the first branch branch 42, The second branch tractor 44 is branched at its distal end and one is supplied to the third frictional element C3 via the control switch valve 38 as operating pressure and at the same time the fail safe valve 40, and the other is configured to be able to supply the hydraulic pressure to the pressure regulating valve 8 of the pressure regulating means via the high-low pressure valve 48.

The fourth speed line 32 is configured to communicate with the left end of the rear clutch release valve 50 and the right end of the 2-3 / 4-3 shift valve 46 to control these valves.

The timing control line 52 is connected to the first-speed line 34 to allow the first-speed pressure flowing along the line to be used as the control pressure of the control switch valve 38 and the high-low pressure valve 46 , Which is enabled by the fifth solenoid valve S5 disposed on the timing control line 52. [

The hydraulic pressure supplied to the backward first control line 56 when the manual valve 16 is in the reverse range is transmitted through the rear clutch release valve 50 and the 2-3 / 4-3 shift valve 46 The hydraulic pressure is supplied to the fourth friction element C4 and the hydraulic pressure supplied to the second backward control line 58 is transmitted to the second friction element C4 via the 1-2 shift valve 36 5 friction element (C5).

A part of the hydraulic pressure supplied to the fourth friction element C4 can be simultaneously supplied to the release side chamber h2 of the second friction element C2.

In the valves forming the hydraulic pressure distributing means as described above, the 1-2 shift valve 36 controls the hydraulic pressure supplied from the first pressure control valve 18 while being controlled by the second-speed pressure of the shift control valve 26 The hydraulic pressure is supplied to the switch valve 38 and the 2-3 / 4-3 shift valve 46 so that the hydraulic pressure is supplied to the friction element connected to the 2-3 / 4-3 shift valve 46, and the hydraulic pressure supplied to the reverse second control line 56 is directly So that the oil can be supplied to the fifth friction element C5.

The control switch valve 38 is operated by the control pressure generated in accordance with the operation of the fifth solenoid valve S5 for controlling the hydraulic pressure supplied from the first speed line 34, And a function of supplying the control pressure of the first pressure control valve 18 via the third-speed line pressure and the 1-2 shift valve 36 to the fail-safe valve 40 and the third friction element C3 Respectively.

Of course, the hydraulic pressure supplied to the fail-safe valve 40 is selectively supplied to the operating-side chamber h1 of the second friction element C2.

The control switch valve 38 replaces the operating pressure of the operating chamber h1 of the second friction element C2 with the second-speed pressure during the 4 to 2 skip-shift, and the operating pressure of the third friction element C3 And the first pressure control valve 18 to control the release pressure.

The second branch passage 44 of the third-speed conduit 30 communicating with the control switch valve 38 forms the end circulation conduit 60 to form the orifice 62 therein, A check valve 64 capable of shutting off the hydraulic pressure supplied to the control switch valve 38 is formed on the check valve 44.

The inlet of the orifice 62 and the check valve 64 communicate with each other and the distal end of the orifice 62 communicates with a port through which the third valve pressure can be supplied to the safe valve 40 via the control switch valve 38 And a second branch tractor 66 which is connected to the second branch tractor 66.

Accordingly, the hydraulic pressure is supplied to the third friction element (C3) through the second branch passage (44) in the third to fourth gears, and the third branch passage (66) is connected to the fail safe valve ) As the control pressure.

The hydraulic pressure supplied to the third friction element (C3) is blocked by the orifice (62) when the second and third speed transmission control units of the vehicle can not be operated or when the shift phenomenon of the shift valves occurs and the hold is made in the third speed Only the first frictional element C1 and the fourth frictional element C4 are operated to hold the planetary gear set at the third speed so as to prevent the occurrence of the interlock phenomenon in the planetary gear set.

For this operation, the control switch valve 38 includes a port for receiving the control pressure from the timing control line 52 connected to the first-speed line 34 to the right end; A port for receiving a control pressure of the first pressure control valve 18 via the 1-2 shift valve 36; A port for receiving hydraulic pressure from the second and third branch passages 44 and 66 of the second-speed channel 28 and the third-speed channel 30 of the shift control valve 26, respectively; And a port for selectively supplying the hydraulic pressure supplied to the port to the fail-safe valve 50 and the third friction element C3. The port receiving the hydraulic pressure from the first- 5 solenoid valve (S5).

The fail safe valve 40 controls the hydraulic pressure supplied to the first friction element C1 and the operating pressure supplied to the operating side chamber h1 of the second friction element C2 while being controlled by the second and third speed pressures Control or discharge occurs.

For this operation, the fail-safe valve 40 has three ports communicating with the control switch valve 38; A port connected to the second-speed line 28 of the shift control valve 48; And a port for supplying the hydraulic pressure supplied from the control switch valve 38 to the operation-side chamber h1 of the second friction element C2.

The third-speed pressure via the control switch valve 38 is connected to a port formed at the rightmost end of the valve. The second-speed pipeline 28 is connected to the left port of the port, So that hydraulic pressure can be applied.

The high-low pressure valve 48 is controlled to be supplied with the control pressure by the on / off control of the fifth solenoid valve S5 from the timing control line 52. After the completion of the third-speed shift, To the pressure regulating valve 8 so as to vary the line pressure.

In the drawing, reference character S6 denotes a sixth solenoid valve for controlling the damper clutch control valve 12 to operate or release the damper clutch.

1, the oil pressure discharged from the oil pump 4 is regulated to a constant oil pressure by the pressure control valve 8, And is then supplied to the damper clutch control valve 12 and the first and second pressure control valves 18 and 20, respectively.

At this time, the third and fourth solenoid valves S3 and S4, which are duty-controlled by the transmission control unit, are controlled to the OFF state, and the spool of these pressure control valves is maintained in the neutral state do.

2 is a diagram showing the hydraulic pressure flow in the shifting process when the reverse (R) range is selected from the neutral (N) range. At this time, the hydraulic pressure from the manual valve 16 is transmitted to the rearward first control line 56, Side chamber h2 and the fourth friction element C4 of the second friction element C2 via the clutch release valve 50 and the 2-3 / 4-3 shift valve 46 as shown in Fig. A part of the hydraulic pressure supplied to the manual valve 16 is controlled by the NR control valve 22 by the duty control of the third solenoid valve S3 so that the reverse second control line 58 and the 1-2 shift valve 36 To the fifth friction element C5.

After the hydraulic pressure is supplied through the above-described path, the third solenoid valve S3 is turned off, and the hydraulic pressure supplied to the fifth friction element C5 changes from the control pressure to the drive pressure, thereby completing the reverse shift.

When the selector lever is selected as the running (D) range in the neutral state N, a part of the hydraulic pressure supplied to the manual valve 16 is supplied to the shift control valve 26 and the first , And two pressure control valves (18) and (20).

At this time, the first and second solenoid valves S1 and S2 of the shift control means are all controlled to be in an ON state, and the port of the shift control valve 26 is maintained as it is in the initial state.

In this state, the hydraulic pressure supplied to the first and second pressure control valves 18 and 20 of the pressure control means is blocked by the first pressure control valve 18 by the on-control of the third solenoid valve S3, The hydraulic pressure supplied to the second pressure control valve 20 is transmitted to the first friction element C1 through the rear clutch release valve 50 by the off control of the fourth solenoid valve S4, To complete the 1-speed control.

When the throttle valve opening rate increases with the vehicle speed increasing at the first speed control state, the transmission is shifted to the second speed. At this time, as shown in FIG. 4, the transmission control unit controls the third solenoid The duty of the valve S3 is controlled and the first solenoid valve S1 is controlled to be in the off state.

Then, the hydraulic pressure supplied through the timing control line 52 is supplied to the control switch valve 38 and the high-low pressure valve 46 by the OFF control of the fifth solenoid valve S5, .

The second-speed pressure supplied from the shift control valve 26 is supplied to the left port of the 1-2 shift valve 36 and the valve spool thereof is moved to the right in the figure, and at the same time, And the hydraulic pressure supplied to the fail-safe valve 40 moves its valve spool to the left in the figure so that the control pressure of the first pressure control valve 18 by the duty control of the third solenoid valve S3 is reduced Side chamber h1 of the second chamber C2.

5, when the third solenoid valve S3 is turned off, the pressure supplied to the operating chamber h1 of the second friction element C2 is converted from the control pressure to the drive pressure, Speed control is completed.

When the opening of the throttle valve increases as the vehicle speed further increases in the second-speed control state as described above, the first and second solenoid valves S1 and S2 of the shift control means are all turned off And the duty of the third solenoid valve S3 is controlled.

The hydraulic pressure supplied to the operating chamber h1 of the second friction element C2 is converted into the control pressure by the duty control of the third solenoid valve S3 and is transmitted to the second control valve 26 via the second speed channel 28 The hydraulic pressure of the third-speed line 30 flows into the left port of the 2-3 / 4-3 shift valve 46 and the hydraulic pressure of the third-speed line 30 flows into the left port of the 2-3 / 4-3 shift valve 46, And is supplied to the control switch valve 38 and the high-low pressure valve 48. [

Accordingly, the hydraulic pressure in the 2-3 / 4-3 shift valve 46 is supplied to the disengagement side chamber h2 and the fourth friction element C4 of the second friction element C2 during the second speed control, 2 friction element C2 and at the same time actuates the fourth friction element C4.

In addition, the control valve valve 38 maintains the state in which the valve valve spool is moved to the left in the drawing by the OFF control of the fifth solenoid valve S5, so that the third- C3.

The third friction element C3 is finally made after the operation control of the second friction element C2 and the fourth friction element C4.

In this state, if the fifth solenoid valve S5 that has been controlled to be off-controlled is controlled at the end of the shift, as shown in Fig. 7, the valve spools of the control switch valve 38 and the high- Whereby the pressure supplied to the operating chamber h1 of the second friction element C2 is converted to the second speed pressure and at the same time the hydraulic pressure supplied to the third friction element C3 is transmitted to the first pressure control valve The transmission is converted into and supplied to the first-speed pressure via the first-speed control valve 18 to complete the shift.

The hydraulic pressure of the third-speed line 30 is supplied to the pressure regulating valve 8 through the high-low pressure valve 48 to regulate the line pressure.

That is, when the fifth solenoid valve S5 is controlled to be in an ON state, the valve spool of the high-low pressure valve 48 is not in the second-to- And variable from the time of moving to the right side.

The line pressure control as described above is to substantially lower the line pressure. This is to reduce the driving loss of the oil pump so as to obtain the effect of improving the fuel efficiency at the high-speed stage.

When the vehicle speed further increases and the opening ratio of the throttle valve increases in the third speed control state as described above, the transmission control unit controls the first solenoid valve S1 to be turned on , The second solenoid valve S2 is controlled to be in an off state, the third solenoid valve S3 is subjected to duty control, and the fifth solenoid valve S5 is controlled to be off.

The hydraulic pressure supplied to the operating side chamber h1 of the second frictional element C2 is supplied with the control pressure by the duty control of the third solenoid valve S3, (28), (30), and (32).

Accordingly, the pressure in the fourth speed line 32 controls the rear clutch release valve 50 and the 2-3 / 4-3 shift valve 46 to control the rear clutch release valve 50 and the 2-3 / 4- -3 shift valve 46 to the right and left, respectively.

The operating pressure supplied to the first friction element C1 is quickly discharged through the discharge port Ex of the rear clutch release valve 50 and at the same time the operating force of the fourth friction element C4 and the second friction element C2 The operating pressure supplied to the release side chamber h2 flows through the manual valve 16 via the 2-3 / 4-3 shift valve 46, the rear clutch release valve 50 and the reverse first control line 54, .

At this time, the release pressure discharged from the fourth friction element C4 and the release-side chamber h2 of the second friction element C2 is controlled by the duty control pressure supplied to the operation-side chamber h1 .

The hydraulic pressure for varying the line pressure is released through the discharge port (Ex) of the high-low pressure valve (48) by the off control of the fifth solenoid valve (S5), and the line pressure control is temporarily stopped.

9, after the fifth solenoid valve S5 is controlled to be on, the valve spool of the control switch valve 38 is moved to the right side in the figure so that the second friction element C2 And the third-speed pressure is supplied to the pressure-regulating valve 8 through the high-low pressure valve 48 to change the line pressure so that the fourth-speed control is performed while the second-speed pressure is supplied to the operating- .

When the downshifting is performed from the fourth speed to the third speed, as shown in FIG. 10, the first solenoid valve (fourth solenoid valve) The hydraulic pressure supplied to the fourth speed line 32 is discharged through the shift control valve 26 so that the valve spool of the rear clutch release valve 50 is moved to the left.

The operating pressure supplied to the operating chamber h1 of the second frictional element C2 is changed to the duty controlled duty of the third solenoid valve S3 by the OFF control of the fifth solenoid valve S5, A part of the control pressure thereof is supplied to the release side chamber h2 of the second friction element C2 and the fourth friction element C4 via the 2-3 / 4-3 shift valve 46.

The control pressure of the first pressure control valve 18 by the duty control of the fourth solenoid valve S4 is supplied to the first friction element C1 through the rear clutch release valve 50 to be shifted It will be lost.

That is, during the 4 → 3 shift, the operating pressure of the first friction element C1 is supplied by the duty control of the fourth solenoid valve S4, so that the shift shock does not occur largely, It is possible to prevent a temporary state from being brought into a neutral state.

11 is a diagram for explaining a 3? 2 downshifting process. At this time, the second solenoid valve S2, which is controlled to be off in the third speed, is turned on to control the hydraulic pressure supplied to the third friction element C3 to 3 And quickly discharged through the quick line 30 and the shift control valve 26.

The valve spool of the 2-3 / 4-3 shift valve 46 is shifted to the left in the drawing and the hydraulic pressure Pc supplied to the release side chamber h2 and the fourth friction element C4 of the second friction element C2 Is discharged through the manual valve 16 through the 2-3 / 4-3 shift valve 46, the rear clutch release valve 50, and the reverse first control line 54. [

The hydraulic pressure supplied to the operating chamber h1 of the second friction element C2 is changed to the control pressure by the duty control of the third solenoid valve S3 and the off control of the fifth solenoid valve S5, After the completion of the third solenoid valve S3, the third solenoid valve S3 is controlled to be off-controlled to be re-supplied to the first-speed pressure to complete the shifting.

12 shows the hydraulic pressure state at the time of 2 → 1 downshifting. At this time, the first solenoid valve S1 is kept in the off state and is controlled to be in the on state at the end of the shift, and the second solenoid valve S2 And the third and fifth solenoid valves S3 and S5 are maintained in the off state.

Accordingly, the hydraulic pressure supplied to the second-speed channel 28 is quickly discharged through the discharge port Ex of the shift control valve 26, and the hydraulic pressure supplied to the operating-side chamber h1 of the second friction element C2 Is shifted through the fail-safe valve (40) and a 2 to 1 shift is performed.

The third and fourth solenoid valves S3 and S4 perform duty control while the fifth solenoid valve S5 is in the ON state (fourth state). In this state, .

The hydraulic pressure supplied to the third and fourth speeds 30 and 32 is discharged through the discharge port of the shift control valve 26 so that the rear clutch release valve 50 and the 2-3 / 4-3 shift valve 46 ) Is moved to the left in the drawing.

The hydraulic pressure supplied to the third friction element C3 by the duty control of the third solenoid valve S3 is discharged through the discharge port of the first pressure control valve 18 and the second pressure control valve 20 ) Is supplied to the first friction element C1 via the rear clutch release valve 50, so that the shifting is effected.

In the second speed after the 4? 2 skip transmission, the second-speed pressure is supplied to the operating-side chamber h1 of the second friction element C2. In the two speeds after the first speed change, the second friction element C2 is operated The control mode of the first pressure control valve 18 is supplied to the side chamber h1 so that the operating pressure of the operating chamber h1 of the second friction element C2 after the 4? So as to improve the responsiveness. In a normal shift, the shift shock is mitigated to provide a ride comfort.

14 shows a hydraulic pressure flow chart when all the solenoid valves are in an off state due to the inability of the transmission control unit to operate in the fourth speed and the hydraulic pressure is held at the third speed. At this time, the first and second solenoid valves S1, S2, The hydraulic pressure is supplied to the second and third flow paths 28 and 30 and the hydraulic pressure supplied to the fourth flow path 32 is discharged.

The valve spool of the control switch valve 38 is moved to the left in the figure by the OFF control of the fifth solenoid valve S5 so that the fail safe valve 40 is actuated by the operating pressure of the first friction element C1, The control pressure is supplied from the first pressure control valve 18 so that the valve spool of the fail-safe valve 40 is moved to the right in the drawing and the operation which was supplied to the operating side chamber h1 of the second friction element C2 The pressure is released and the third-speed hold state is established.

The reason why the hydraulic pressure is not fully supplied to the third friction element C3 in FIG. 14 is that the supply of the new hydraulic pressure is blocked by the control switch valve 38 and the orifice 62. In this case, But it does not work.

15 shows a hydraulic pressure flow chart when all the solenoid valves are in an off state due to the inability of the transmission control unit to operate in the first and second speeds and the hold is performed in the third speed. At this time, the first and second solenoid valves S1, The hydraulic pressure is supplied to the third-speed pipeline 30 which is not supplied with hydraulic pressure in the second speed.

As a result, the valve spool of the 2-3 / 4-3 shift valve 46 moves to the right in the drawing, and the first pressure control valve 18 waiting therefrom is moved to the release side chamber of the second friction element C2 h2) and the fourth friction element (C4).

The valve spool of the control switch valve 38 moves to the left side in the drawing by the OFF control of the fifth solenoid valve S5 so that the operating pressure of the first friction element C1 and the second- A control pressure is supplied from the first pressure control valve 18 in a state in which the valve is spooled so that the valve spool of the fail-safe valve 40 moves to the left in the drawing and moves to the operating side chamber h1 of the second friction element C2. And the oil pressure is supplied to hold the oil in the third speed.

That is, in the third-speed hold state as described above, the operation of the third friction element (C3) is stopped and interlock phenomenon of the planetary gear set can be prevented.

As described above, in the hydraulic control system according to the present invention, when the transmission control unit can not be operated while the vehicle is running, the safety can be secured by the fail-safe function and the reliability can be improved. 2 skip shift By setting 2 speeds in 2 modes after shifting, the servo band is prevented from loosening during solenoid valve operation after 4-2 skip shift, thus improving durability.

Claims (5)

Pressure regulating means for regulating the hydraulic pressure generated from the oil pump; A manual and automatic control means for forming a shift mode; A hydraulic control means for controlling the transmission feeling and responsiveness to form a smooth transmission mode when shifting; A damper clutch control means for operating the damper clutch of the torque converter; And a hydraulic pressure distributing means for supplying an appropriate hydraulic pressure to the first, second, third, fourth, and fifth friction elements acting on the input and reaction force elements at the respective speed change stages, the hydraulic control system comprising: A port receiving a control pressure from the timing control line connected to the first speed line to the right end; A port to which the first pressure control valve control pressure of the hydraulic control means is supplied; A second hydraulic pressure port for receiving the hydraulic pressure from the second and third branch passages of the second and third hydraulic passages of the shift control valve; And a second solenoid valve connected to the first solenoid valve and the second solenoid valve, wherein the first solenoid valve and the second solenoid valve are connected to the first solenoid valve and the second solenoid valve, respectively. Three ports in communication with the control switch valve; A port connected to the second speed line of the shift control valve; Side chamber of the second friction element while being controlled by the hydraulic pressure supplied to the first friction element and the second-speed pressure while holding the port for supplying the hydraulic pressure supplied from the control switch valve to the operating- A fail-safe valve for controlling the discharge pressure to be supplied to the discharge port; Speed control of the solenoid valve for controlling the control switch valve, and after the completion of the third-speed shift, the third-speed pressure is supplied to the pressure regulating valve of the pressure regulating means, And a line-pressure varying means including a high-low pressure valve for varying the pressure of the hydraulic pressure. 2. The control valve according to claim 1, wherein a branch pipe of the third-speed pipeline communicating with the control switch valve is formed with a circulation pipe at a distal end thereof to form an orifice therethrough, and on the branch pipe a check valve The hydraulic pressure control system comprising: 3. An apparatus according to claim 2, further comprising a further branch passage communicating with the inlet of the orifice and the check valve, the other end of which is selectively communicated to a port through which the third-speed pressure can be supplied to the fail-safe valve via the control switch valve And when the TCU is broken at the first or second speed traveling, the hydraulic pressure supply to the end clutch is delayed to constitute a safety lock. The fail safe valve according to claim 1, wherein the fail-safe valve is connected to a port at which the third-speed pressure via the control switch valve is formed at the rightmost end, and the second-speed duct is connected to the left port of the port, And the hydraulic pressure control system is connected to the hydraulic control system. The solenoid valve according to claim 1, wherein the second speed after the normal 3-2 downshift and the second speed during the 4-2 kick down skip shift are set differently so that the solenoid valve after the 4-2 kick- So that the servo band can be prevented from being loosened.