KR19990002024A - Hydraulic control system of automatic transmission for vehicles - Google Patents

Abstract

It prevents damage to the end clutch due to premature operation of the end clutch during 2 → 3 shifting, and improves the feeling of shifting, and improves durability by preventing the end clutch pressure from decreasing during 3 → 4 and 4 → 3 shifting. For providing a hydraulic control system of an automatic transmission for a vehicle;

Pressure regulating means for regulating the hydraulic pressure generated from the oil pump; Manual and automatic control means for forming a shift mode; Hydraulic control means for adjusting the shifting feeling and responsiveness to form a smooth shifting mode during shifting; Damper clutch control means for operating a damper clutch of the torque converter; A hydraulic distribution means for supplying and disassembling the appropriate hydraulic pressure to the friction elements acting as input and reaction force elements at each shift stage;

A control switch valve for forming the hydraulic pressure distribution means for the end clutch valve which enables the end clutch to be operated at the time of shift completion at 2 → 3 shifting, and allows continuous 3 speed pressure to be supplied to the end clutch at 3 → 4 shifting. Provided is a hydraulic control system for an automatic transmission for a vehicle, which is arranged to control the end clutch pressure on a three-speed pipeline for supplying three-speed pressure to the vehicle.

Description

Hydraulic control system of automatic transmission for vehicles

The present invention relates to a hydraulic control system applied to an automatic transmission for a vehicle, and more particularly, to prevent the burnout of the end clutch due to the early operation of the end clutch during 2 → 3 shifting, and to improve the feeling of shifting, 3 → 4, It relates to a hydraulic control system of an automatic transmission for a vehicle that can improve durability by preventing an end clutch pressure from being lowered during a shift of 4 → 3.

For example, an automatic transmission for a vehicle may hydraulically control a torque converter, a planetary gear set connected to the torque converter, and a friction element for selecting and operating at least one of the operating elements of the planetary gear set according to the driving state of the vehicle. Hydraulic control system.

The hydraulic control system of such an automatic transmission operates the hydraulic pressure generated from the oil pump by selecting a friction element through a control valve, so that an appropriate shift can be automatically performed according to the driving state of the vehicle.

In the conventional configuration of the hydraulic control system, as shown in FIG. 12, the torque converter 202 receives torque from the engine and converts the torque to the transmission side, and the oil and lubrication required for the torque converter and the shift stage control. An oil pump 204 for generating and dispensing the required oil is included.

In the hydraulic pipe line 206 flowing from the oil pump 204, a pressure regulating valve 208 for making the oil flowing along the pipe to a constant pressure, and a torque for constantly adjusting the pressure of the torque converter and the lubricating oil The converter control valve 210 and the damper clutch control valve 212 for increasing the power transmission efficiency of the torque converter are connected to constitute a pressure regulating means and a damper clutch control means.

And some of the oil generated from the oil pump 204, the reducing valve to keep the pressure at all times lower than the line pressure, and operates in conjunction with the position of the selector lever in the driver's seat to switch the flow path The flow path that can be supplied to the manual valve 216 is configured.

The constant hydraulic pressure reduced in the reducing valve 214 is supplied to the first pressure control valve 218 and the second pressure control valve 220 to constitute a hydraulic control means that can be used as the shift stage control pressure.

A part of the hydraulic pressure supplied to the first and second pressure control valves 218 and 220 may use a control pressure of the NR control valve 222 that reduces shift shock when the mode is changed from the neutral range to the reverse range. Making.

The first solenoid valve S1 and the second solenoid valve S2 which are controlled on / off by the transmission control unit to the pipeline 224 through which the hydraulic pressure flows when the manual valve 216 is in the travel D range. The shift control valve 226 which switches the flow path by the function of the communication is communicated with the manual valve 216 to constitute manual and automatic shift control means.

The shift control valve 226 is connected to the second speed pipe 228, the third speed pipe 230, and the fourth speed pipe 232 to control the hydraulic pressure by the shift valves of the hydraulic distribution means for controlling the respective shift stages. It is configured to supply.

In addition, a first speed pipe 234 is branched on the pipe line 224 to supply line pressure to the first and second pressure control valves 218 and 220, and the first and second pressure control valves 218. 220 is configured to switch the flow path by the third, fourth solenoid valve (S3) (S4) so that the first pressure control valve 218 can supply a control pressure to the friction element during the shift control, The second pressure control valve 220 is formed with a flow path for supplying drive pressure to the rear clutch C1 acting as a pressure element of the first speed.

The second speed pipe 228 of the shift control valve 226 is supplied to the left end port of the 1-2 shift valve 236 to control the valve.

In addition, the three-speed pipeline 230 is branched into two pipelines 238 and 240 so that the first branch pipeline 238 is supplied to the left end port of the 2-3 / 4-3 shift valve 242. It is configured to control the valve, the second branch conduit 240 is configured so that the end is branched to supply the hydraulic pressure to the control switch valve 244 and the high-low pressure valve 246.

The four-speed pipe 232 is configured to communicate with the left end port of the rear clutch release valve 248 and the right end of the 2-3 / 4-3 shift valve 242 to control these valves.

In addition, fail-safe operation of the transmission control unit or between the valves of the hydraulic distribution means and at least two friction elements occurs when the stick phenomenon occurs in each of the valves forming the hydraulic distribution means. A fail safe valve 250 is disposed as a safety means for performing a function.

In addition, the manual valve 216 is connected to the timing control conduit 252 so that the hydraulic pressure flowing along the conduit can be used as the control pressure of the control switch valve 244, which is on the timing control conduit 252. It is controlled by the fifth solenoid valve S5 disposed in the.

And when the manual valve 216 is in the reverse (R) range, the hydraulic pressure supplied to the reverse first control conduit 254 is passed through the rear clutch release valve 248 and the 2-3 / 4-3 shift valve 242. The low-reverse acting as a reaction force at the reverse gear stage through the 1-2 shift valve 236 while allowing the hydraulic pressure to be supplied to the front clutch C4 and to the reverse second control pipe 256. It is comprised so that hydraulic pressure may be supplied to brake C5.

A part of the hydraulic pressure supplied to the front clutch C4 can be simultaneously supplied to the release side chamber h2 of the kick-down servo C2.

In such a hydraulic control system, conventionally operating the end clutch C3 after completion of the shift by operation of the release side chamber h2 of the front clutch C5 and the kick-down servo C2 during a shift of 2 → 3. In order to apply the control switch valve 244, the check valve 260 and the orifice 262 on the second branch pipe line 240 of the three-speed pipe line 230 connected to the control switch valve 244 thereof. I am placing it.

Further, in the above, the orifice 262 has a diameter of 0.8 mm in order to prevent the pressure drop of the end clutch C3 during the 3 → 4, 4 → 3 shift.

However, in the hydraulic control system as described above, by supplying hydraulic pressure to the release side chamber of the front clutch and the kick-down servo at the time of 2 → 3 shifting, and controlling the fifth solenoid valve from the off state to the on state, The end clutch is operated by the chamber side pressure of the kick-down servo. At this time, the third speed is blocked by the valve and the low flow rate is supplied by the orifice.The residual pressure is the end clutch at low RPM (approx. 750 RPM). There is a problem in that the end clutch is burned out.

In order to control the operating side chamber of the kick-down servo during 3 → 4, 4 → 3 shifting, the fifth clutch solenoid valve is controlled from on to off during the 3rd and 4th speeds so that the end clutch pressure is changed to 3rd speed. At this time, the three-speed pressure is completely blocked by the check valve, and is supplied through only the orifice, thereby implying a problem that the shifting feeling is reduced due to the lowering of the hydraulic pressure of the end clutch.

Therefore, the present invention has been invented to solve the above problems, the object of the present invention is to prevent the burnout of the end clutch by the early operation of the end clutch during 2 → 3 shifting and at the same time improve the feeling of shift, 3 → 4 In addition, the present invention provides a hydraulic control system of an automatic transmission for a vehicle which can improve durability by preventing a decrease in end clutch pressure during a shift of 4 → 3.

In order to realize this, the present invention includes a pressure regulating means for regulating the hydraulic pressure generated from the oil pump; Manual and automatic control means for forming a shift mode; Hydraulic control means for adjusting the shifting feeling and responsiveness to form a smooth shifting mode during shifting; Damper clutch control means for operating a damper clutch of the torque converter; And hydraulic distribution means for supplying and distributing the appropriate hydraulic pressure to the friction elements acting as input and reaction force elements at each shift stage;

A control switch valve for forming the hydraulic pressure distribution means for the end clutch valve which enables the end clutch to be operated at the shift completion time at 2 → 3 shift, and the continuous 3 speed pressure can be supplied to the end clutch at the 3 → 4 shift. Provided is a hydraulic control system for an automatic transmission for a vehicle that is arranged to be controlled by the end clutch pressure on a three-speed pipeline for supplying three-speed pressure to the vehicle.

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

2 is a block diagram of an end clutch valve applied to the present invention.

3 is a view showing a hydraulic flow state in the driving (D) range 1 speed in the hydraulic control system according to the present invention.

4 is a view showing a hydraulic flow state in the running (D) range 2 speed in the hydraulic control system according to the present invention.

5 is a view showing a hydraulic flow state at the time of driving (D) range 2 → 3 shift in the hydraulic control system according to the present invention.

6 is a view showing a hydraulic flow state at the driving (D) range 3 speed in the hydraulic control system according to the present invention.

Fig. 7 is a graph showing the flow of hydraulic pressure supplied to each friction element during 2 → 3 shift.

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

9 is a view showing a hydraulic flow state at the driving (D) range 4 speed in the hydraulic control system according to the present invention.

Fig. 10 is a graph showing the flow of hydraulic pressure supplied to each friction element in the 3 → 4 shift.

11 is a view showing a hydraulic flow state in the reverse (R) range in the hydraulic control system according to the present invention.

12 is a configuration diagram of a conventional hydraulic control system.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a hydraulic control system according to the present invention, showing a state when the select lever is in the neutral (N) range.

The hydraulic control system according to the present invention includes a torque converter (2) for converting power from the engine to torque transmission to the transmission side, and oil for generating and discharging the oil necessary for the torque converter and the shift stage control, and oil for lubrication. A pump 4.

In the pipeline 6 through which the hydraulic pressure generated from the oil pump 4 flows, a pressure regulating valve 8 for making the oil flowing along the pipeline to a constant pressure, and a torque for constantly adjusting the pressure of the torque converter and the lubricating oil. The converter control valve 10 and the damper clutch control valve 12 for increasing the power transmission efficiency of the torque converter are connected to constitute a pressure regulating means and a damper clutch control means.

The oil generated from the oil pump 4 switches the flow path while operating in conjunction with the reducing valve 14 which controls the pressure to be always lower than the line pressure and the position of the selector lever in the driver's seat. And a flow path that can be supplied to the manual valve 16.

The constant hydraulic pressure reduced in the reducing valve 14 is supplied to the first pressure control valve 18 and the second pressure control valve 20 to constitute a hydraulic control means that can be used as the shift stage control pressure.

Part of the hydraulic pressure supplied to these first and second pressure control valves 18 and 20 is a flow path that can use the control pressure of the NR control valve 22 to reduce the shift shock when the mode is changed from the neutral range to the reverse range. Making.

The first solenoid valve S1 and the second solenoid valve S2 which are controlled on / off by the transmission control unit in the pipeline 24 through which the hydraulic pressure flows when the manual valve 16 is in the travel D range. The shift control valve 26 which switches a flow path by the function of the communication is connected, and comprises the manual and automatic shift control means with the manual valve 16 mentioned above.

The shift control valve 26 is connected to the second speed pipe 28, the third speed pipe 30, and the fourth speed pipe 32 so as to control the hydraulic pressure by the shift valves of the hydraulic distribution means for controlling the respective shift stages. It is configured to supply, the first pipe line 34 is branched on the pipe line 24 to supply the line pressure to the first and second pressure control valves (18, 20).

The first and second pressure control valves 18 and 20 are configured to switch the flow path by the third and fourth solenoid valves S3 and S4, so that the first pressure control valve 18 is in shift control. A control pressure can be supplied to the friction element, and the second pressure control valve 20 has a flow path formed so that the drive pressure can be supplied to the rear clutch C1 acting as the pressure element at the first speed.

The second speed pipeline 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 to be supplied to the control switch valve and the fail safe valve which will be described later. A flow path will be formed so that it can

In addition, the three-speed pipeline 30 is branched into two pipelines 38 and 40 so that the first branch pipeline 38 is supplied to the left end port of the 2-3 / 4-3 shift valve 42. It is configured to control the valve, the second branch conduit 40 is configured so that the end is branched to supply the hydraulic pressure to the control switch valve 44 and the high-low pressure valve 46.

The four-speed pipeline 32 is configured to communicate with the K-side end port of the rear clutch release valve 48 and the right end of the 2-3 / 4-3 shift valve 42 to control these valves.

In addition, fail-safe operation of the transmission control unit or between the valves of the hydraulic distribution means and at least two friction elements occurs when the stick phenomenon occurs in each of the valves forming the hydraulic distribution means. A fail safe valve 50 is disposed as a safety means for performing a function.

In addition, the manual valve 16 is connected to the timing control conduit 52 so that the hydraulic pressure flowing along the conduit can be used as the control pressure of the control switch valve 44, which is on the timing control conduit 52. It is controlled by the fifth solenoid valve S5 disposed in the.

And when the manual valve 16 is in the reverse (R) range, the hydraulic pressure supplied to the reverse first control conduit 54 is forwarded through the rear clutch release valve 48 and the 2-3 / 4-3 shift valve 42. A low-reverse brake that allows hydraulic pressure to be supplied to the clutch C4 and at the same time the hydraulic pressure supplied to the reverse second control conduit 56 acts as a reaction element in the reverse shift stage via the 1-2 shift valve 36. It is comprised so that hydraulic pressure may be supplied to C5.

A part of the hydraulic pressure supplied to the front clutch C4 can be simultaneously supplied to the release side chamber h2 of the kick-down servo C2.

In the hydraulic control system as described above, the present invention provides an end clutch (3) on the second branch conduit (40) of the three-speed conduit (30) for supplying three-speed pressure to the control switch valve (44) forming the hydraulic distribution means. C3) The end clutch valve 60 can be arranged which can be controlled by the working pressure.

In the above, the control switch valve 44 is controlled by the fifth solenoid valve S5 and the kick-down servo C2 is operated at the second, third and fourth speeds of the second speed line 28 of the shift control valve 26. The actuating side chamber h1 or the end of the kick-down servo C2, supplied to the side chamber h1 and supplied with the control pressure of the first pressure control valve 18 via the 1-2 shift valve 36. It has a function to supply the clutch C3.

And the configuration thereof, as shown in Figure 2, the valve body, the first port 62 is supplied with the control pressure of the fifth solenoid valve (S5), and the second port 64 in communication with the second speed pipeline (28) ), A third port 66 supplied with control pressure of the first pressure control valve 18, a fourth port 68 supplied with hydraulic pressure from the end clutch 60, and the second port 64. Alternatively, the fifth clutch 70 may supply the hydraulic pressure flowing into the third port 66 to the fail safe valve 50, and the hydraulic pressure supplied to the third port 66 or the port 68 may be an end clutch valve. And a sixth port 72 for supplying to any one port of 60.

The valve spool incorporated into the valve body may include a first land configured to selectively open the second port 64 and the fifth port 70 while one surface of the valve spool is operated by the hydraulic pressure supplied to the first port 62. 74, a second land 76 for selectively communicating the third port 66 with the fifth port 70 and the sixth port 72, and optionally the sixth port 68 with the fourth port 68. And a third land 78 which communicates with the port 72, wherein the third land 78 is always pushed by the ball member 80 to push the valve spool toward the first port 62. Is built into the state.

Accordingly, the valve spool in which the fifth solenoid valve S5 is controlled to be off moves to the left side of the drawing to communicate the third port 66 with the fifth port 70 and the fourth port 68 with the sixth port ( 72. On the contrary, when the fifth solenoid valve S5 is controlled on, the valve spool moves to the right side of the drawing to communicate the second port 64 with the fifth port 70, and the third port 66. ) Is in communication with the sixth port 72, the fourth port 68 is to perform the closing operation.

And the end clutch valve 60 is controlled by the pressure supplied from the control switch valve 44 to the end clutch C3 through the sixth port 72, the third speed pressure is the end clutch through the control switch valve 44 Perform a function to be supplied to (C3).

As a result, the valve body communicates with the first port 84 communicating with the sixth port 72 of the control switch valve 44 and the second branch pipe 40 of the three-speed pressure pipe 30. And a third port 88 for selectively supplying the hydraulic pressure thereof to the fourth port 68 of the control switch valve 44 while selectively communicating with the upper second port 86. It has a discharge port 90 for quickly discharging the hydraulic pressure discharged from the three port (88).

The valve spool embedded in the valve body has a first land 92 that opens and closes the discharge port 90 while acting by hydraulic pressure supplied to the first port 84, and optionally the second port 86. And a second land 94 which communicates with the third port 88, wherein one side of the second land 94 has a carbon member 96 thereon so that the valve spool is always in the first port 84. You get the force to move to the side.

Accordingly, when the end clutch operating pressure flows through the first port 84, the valve spool moves to the right side of the drawing to communicate the second and third ports 86 and 88, and when the inflow of the operating pressure is blocked, The valve spool is moved to the left side of the drawing by the elastic force of the elastic member 96 to communicate with the third port 88 and the fourth port 90 to perform the discharge operation.

In the figure, reference numeral S6 denotes a sixth solenoid valve for controlling the damper clutch control valve 12 to activate or deactivate the damper clutch.

In the hydraulic control system of the present invention as described above, as shown in FIG. 1, in the neutral (N) range, the hydraulic pressure discharged from the oil pump 4 is regulated to a constant hydraulic pressure by the pressure control valve 8 while reducing the reducing valve. After the pressure is reduced through 14, the damper clutch control valve 12 and the first and second pressure control valves 18 and 20 are respectively supplied.

At this time, the third and fourth solenoid valves S3 and S4 that are duty controlled by the transmission control unit are controlled to be in an off state to maintain a neutral state in a state in which the spools of these pressure control valves are moved to the right side in the drawing. do.

When the selector lever is selected as the driving range D in the neutral state N, a part of the hydraulic pressure supplied to the manual valve 16 is shifted to the shift control valve 26 and the first, as shown in FIG. 2 is supplied to the 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 in the on state, and thus maintain the port of the shift control valve 26 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 shut off at the first pressure control valve 18 by the third solenoid valve S3 being turned on. The hydraulic pressure supplied to the second pressure control valve 20 is the first friction element C1 acting as an input element at the first forward speed via the rear clutch release valve 48 by the off control of the fourth solenoid valve S4. Is supplied to complete the 1-speed control.

If the opening rate of the throttle valve is increased while the vehicle speed is increased in such a 1-speed control state, the shift is performed at 2 speeds, as shown in FIG. 4;

The transmission control unit controls the first solenoid valve S1 that has been controlled in the on state to the off state and supplies the hydraulic pressure supplied to the shift control valve 26 to the second speed pipe 28.

And while the third solenoid valve (S3) is duty-controlled in the off state, the hydraulic pressure supplied from the first speed pipe (34) to be controlled by the first pressure control valve 18 to control the control pressure 1-2 shift valve (36). By supplying the control switch valve 44 and the fail-safe valve 50 to the actuation side chamber h1 of the kick-down servo C2, the second speed shift is completed.

In the above two speed control state, when the vehicle speed is further increased and the opening degree of the throttle valve is increased, as shown in FIG. 5, the first and second solenoid valves S1 and S2 of the shift control means are turned off. do.

Under such control, hydraulic pressure flows into the second speed pipe 28 and the third speed pipe 30, and at this time, the hydraulic pressure of the third speed pipe 30 passes to the left port of the 2-3 / 4-3 shift valve 42. As it flows in, it moves the valve spool to the right as seen in the drawing, with some hydraulic pressure waiting at the end clutch valve 60 and the high-low pressure valve 46.

The first speed control pressure controlled by the first pressure control valve 18 by the duty control of the third solenoid valve S3 is shifted by a part of 2-3 / 4-3 via the 1-2 shift valve 36. The valve 42 is supplied to the release chamber h2 of the front clutch C4 and the kick-down servo C2, and a part of the kick-down band is passed through the control switch valve 44 and the fail-safe valve 50. It is supplied to the operating side chamber h2 of (C2) to stop the operation of the kick-down servo C2.

In addition, a part of the hydraulic pressure flowing to the timing control pipeline 46 acts on the high-low pressure valve 46 to maintain the state in which the valve spool is moved to the left in the drawing.

In this state, as shown in FIG. 6, when the fifth solenoid valve S5 that is being controlled to be on is controlled on, the valve side spool of the control switch valve 44 moves to the right, and the operating side chamber of the kick-down servo C2 is moved. The pressure supplied to (h1) is converted from the control pressure to the second speed line 28 pressure.

Then, the control pressure of the first pressure control valve 18 supplied to the release side chamber h2 of the front clutch C4 and the kick-down servo C2 is controlled by the off-line control of the third solenoid valve S3. Is supplied to the release side chamber (h2) of the front clutch (C4) and the kick-down servo (C2), and some of its hydraulic pressure is supplied to the end clutch (C3) through the control switch valve (44). As a part of the hydraulic pressure supplied to the end clutch C3 thereof is supplied to the end clutch valve 60, the third speed pressure that is waiting for the valve spool of the valve 60 is moved to the right in the drawing. Wait at (44).

In addition, a part of the hydraulic pressure supplied to the end clutch C3 at the third speed control is supplied to the pressure control valve 8 through the high-low pressure valve 46 to control the line pressure, thereby adjusting the line pressure. During the 2 → 3 shift, the valve spool of the high-low pressure valve 46 moves to the left side, and when the 3 speed shift is completed, the valve spool moves to the right by the ON control of the fifth solenoid valve S5 and the pressure control valve ( 8) to control line pressure at 3rd speed.

And the line pressure control as described above is to substantially lower the line pressure, which is to reduce the driving loss of the oil pump to obtain the effect of improving the fuel efficiency in the high-speed stage, in the case of adjusting the line pressure in this way As described above, it is possible to independently control the line pressure instead of adjusting the damper clutch.

In addition, the operation of the end clutch C3 is controlled by the fifth solenoid valve S5 and the end clutch valve 60 at the time of completion of the shift when shifting from the second to the third speed as described above. It is possible to prevent burnout by the early operation of the end clutch C3.

The hydraulic pressure supplied to each friction element of the 2 → 3 shifting process as described above is formed as shown in FIG. 7, during the shift of the kick down servo C2 while the pressure of the rear clutch C1 is kept constant. The pressure of the operating side chamber h1 drops largely by the duty control of the third solenoid valve S3 and then rises before the shift is completed, and the front clutch C4 and the kick-down servo C2 are released. The pressure of the side chamber h2 gradually rises as the duty control pressure of the third solenoid valve S3 is supplied, and then greatly increases just before completion of the shift, and these hydraulic pressures form a hydraulic pressure that is constantly lowered after the completion of the third shift. do.

And the operating pressure of the end clutch (C3) takes the form that the supply rises at the time of completion of the shift, which is the conventional hydraulic pressure is supplied from when the hydraulic pressure is supplied to the release side chamber (h2) of the kick-down servo (C2) In comparison, since early operation is not performed, it is possible to prevent burnout of the end clutch.

When the vehicle speed is further increased and the opening ratio of the throttle valve is increased in the three-speed control state as described above, the transmission control unit turns on the first solenoid valve S1 as shown in FIG. The 5 solenoid valve S5 is controlled to be in an off state to allow hydraulic pressure to flow through all of the 2nd, 3rd and 4th speed pipelines 28, 30 and 32, and the duty control of the 3rd solenoid valve S3 is carried out.

Then, the hydraulic pressure supplied to the operating side chamber h1 of the kick-down servo C2 in the state where the end clutch C3 is normally operated is controlled by the control switch valve 44 of the third solenoid valve S3. The pressure is changed to the duty control pressure, and the valve spool of the rear clutch release valve 48 moves to the right in the drawing and the valve of the 2-3 / 4-3 shift valve 42 is supplied by the supply of the four-speed line 32 pressure. The spool will move to the left in the drawing.

Accordingly, the hydraulic pressure supplied to the rear clutch C1 is accelerated through the discharge port Ex of the rear clutch release valve 48, and the release side chamber h2 of the front clutch C4 and the kick-down servo C2 is released. The hydraulic pressure supplied to the exhaust gas is discharged through the manual valve 16 through the 2-3 / 4-3 shift valve 42 and the reverse second control conduit 50, and the hydraulic pressure supplied to the pressure regulating valve 8 is also high. -Discharge through the low pressure valve (46).

In the above state, as shown in FIG. 9, when the fifth solenoid valve S5 is controlled to the on state, the valve spool of the control switch valve 44 is moved to the right in the drawing to operate the kick-down servo C2. 4 speed control is completed by supplying 2 speed pressure to the side chamber h1.

Of course, at this time, a part of the third speed pressure is supplied to the pressure regulating valve 8 through the high-low pressure valve 46 by the on control of the fifth solenoid valve S5 to adjust the line pressure.

In addition, when the shift of 3 → 4 as described above, the operating pressure of the end clutch C3 is fixed at a third speed so that it is constantly supplied, so that the burnout of the end clutch C3 can be prevented from occurring during the shifting process. Will be.

The hydraulic pressure supplied to each friction element in the 3 to 4 shifting process as described above is formed as shown in FIG. 10. During the shifting, the pressure of the rear clutch C1 is discharged and is rapidly lowered and then disappears. The pressure of the operating side chamber h1 of (C2) drops largely by the duty control of the third solenoid valve S3 and then rises before the shift is completed, and the front clutch C4 and the kick-down servo ( The pressure of the release side chamber h2 of C2) gradually decreases while the duty control pressure of the third solenoid valve S3 is supplied, and then completely disappears immediately before shift completion.

And the operating pressure of the end clutch (C3) is increased by a certain amount at the beginning of the shift to maintain the state, but after the shift is completed as the state of the third speed, which is significantly lowered in the shifting process, compared with the conventional, which is raised at the completion of the shift, It is possible to prevent burnout of the end clutch due to a drop in operating pressure during the shifting process.

The reason why the end clutch pressure can rise during the shift is because the third speed pressure is waited at the control switch valve 44 through the end clutch valve 60 and then is supplied quickly.

Accordingly, it is possible to prevent a decrease in the operating pressure of the end clutch when shifting 2 → 4, 3 → 4, 4 → 3.

And when the driver selects the selector lever to the reverse (R) range for the reverse, as shown in Figure 11, a part of the hydraulic pressure supplied to the manual valve 16 is controlled by the duty control of the third solenoid valve (S3) The NR control valve 22 and the 1-2 shift valve 36 are supplied to the low-reverse brake C5 which acts as a reaction force element in the reverse direction.

In addition, some of the hydraulic pressure is directly controlled by the manual valve 16, when the reverse through the reverse control line 54, the rear clutch release valve 48, 2-3 / 4-3 shift valve 42 The reverse control is completed while being supplied to the fourth friction element C4 serving as an input element.

As described above, according to the present invention, it is possible to prevent burnout of the end clutch due to the early operation of the end clutch at the time of 2 → 3 shifting.

In the case of 3 → 4, 4 → 3 shift, the end clutch pressure can be prevented from being lowered to prevent burnout due to slip occurrence, thereby improving durability.

Claims (5)

Pressure adjusting means for regulating the hydraulic pressure generated from the oil pump; Manual and automatic control means for forming a shift mode; Hydraulic control means for adjusting the shifting feeling and responsiveness to form a smooth shifting mode during shifting; Damper clutch control means for operating a damper clutch of the torque converter; And hydraulic distribution means for supplying and distributing the appropriate hydraulic pressure to the friction elements acting as input and reaction force elements at each shift stage; A control switch valve for forming the hydraulic pressure distribution means for the end clutch valve which enables the end clutch to be operated at the shift completion time at 2 → 3 shift, and the continuous 3 speed pressure can be supplied to the end clutch at the 3 → 4 shift. A hydraulic control system for an automatic transmission for a vehicle, which is arranged to be controlled by the end clutch pressure on a three-speed pipeline for supplying three-speed pressure to the vehicle. The control switch valve of claim 1, wherein the control switch valve is controlled by a solenoid valve and simultaneously supplies the second-speed line pressure of the shift control valve, which is a manual or automatic control means, to the actuating side chamber of the kick-down servo, which is a friction member, at speeds 3 and 4. The hydraulic pressure of the automatic transmission for a vehicle, characterized in that the control pressure of the first pressure control valve, which is a hydraulic control means via the 1-2 shift valve, can be selectively supplied to the actuating side chamber and the end clutch of the kick-down servo. Control system. The control switch valve of claim 1, wherein the control switch valve comprises: a first port supplied with the control pressure of the solenoid valve, a second port communicating with the second speed pipeline, and a third port supplied with the control pressure of the first pressure control valve; And a fourth port receiving hydraulic pressure from the end clutch, a fifth port supplying hydraulic pressure flowing into the second port or the third port to the failsafe valve, and a hydraulic pressure supplied to the third port or the fourth port. A valve body comprising a sixth port for supplying to any one port of the end clutch valve; A first land for selectively opening the second port and the fifth port while acting by hydraulic pressure supplied to the first port, and a third port for selectively communicating the third port with the fifth port and the sixth port; A second land, and a third land configured to selectively communicate the fourth port with the sixth port, wherein the third land includes a valve spool which is always pushed toward the first port by the ballistic member; Hydraulic control system of an automatic transmission for a vehicle, characterized in that comprises a. The hydraulic control system of claim 1, wherein the end clutch valve is controlled by a pressure supplied to the end clutch through the control switch valve so that the third speed pressure can be supplied to the end clutch. 6. The end clutch valve of claim 1 or 5, wherein the end clutch valve has a first port in communication with the control switch valve, a second port in communication with the second branch conduit of the three-speed pressure conduit, and its hydraulic pressure in selective communication with the second port. A valve body having a third port for supplying to the fourth port of the control switch valve and a discharge port for quickly discharging the hydraulic pressure discharged from the third port; A first land opening and closing the discharge port while acting by the hydraulic pressure supplied to the first port, and a second land selectively communicating the second port and the third port, wherein one side of the second land is provided. The valve spool has a force that is moved to the first port side is carried by the bullet member; Hydraulic control system of an automatic transmission for a vehicle, characterized in that comprises a.