KR101080797B1 - Hydraulic control system of 8-shift automatic transmission for vehicles - Google Patents

Abstract

8 forward speeds are realized by arranging a pressure control valve, a pressure switch valve, and a plurality of spool valves controlled by respective proportional control solenoid valves on a flow path for transmitting hydraulic pressure to each of the four clutches and the two brakes.

Friction elements operating in the R and L ranges operate in the N range to improve shift shock during N ↔ R, N ↔ D static shifting, and to make the fail safe function more stable, thereby improving confidence in the automatic transmission. To provide a hydraulic control device for a vehicle 8-speed automatic transmission.

Pressure control valve, pressure switch valve, fail safe valve, switching valve

Description

HYDRAULIC CONTROL SYSTEM OF 8-SHIFT AUTOMATIC TRANSMISSION FOR VEHICLES}

The present invention relates to a hydraulic control device for an 8-speed automatic transmission for a vehicle, and more particularly, to simplify the control during N ↔ R and N ↔ D static shifting, thereby improving controllability and improving shift shock, and fail-safe function. By more stable, the hydraulic control apparatus of the 8-speed automatic transmission for a vehicle that can improve the confidence in the automatic transmission.

For example, an automatic transmission for a vehicle has a torque converter and a power train, which is a multi-stage transmission gear mechanism connected to the torque converter, and selectively selects one of the operating elements of the power train according to the driving state of the vehicle. It will have a hydraulic control device for operation.

This automatic transmission selects a friction element of the power train according to the driving conditions, and a power train composed of a complex planetary gear set and a plurality of friction elements, by combining at least two simple planetary gear sets to obtain a required shift stage. It is made to include a hydraulic control device to be operated as.

In addition, the powertrain and hydraulic control device described above are developed and applied in different forms according to each automobile manufacturer. Currently, the four-speed automatic transmission is the mainstream, and the fuel efficiency and the efficient use of engine driving power are the main factors. In order to improve performance, up to six-speed and seven-speed automatic transmissions have been realized.

However, in recent years, an eight-speed automatic transmission has been developed to satisfy an external situation that is not satisfied with a seven-speed automatic transmission, and is required to increase the fuel efficiency and the demand for a high-performance passenger car due to exhaust gas regulations and to increase the number of automatic transmissions.

Accordingly, the present invention implements eight forward speeds by independently controlling six friction elements with six proportional control solenoid valves and one on / off solenoid valve, while simplifying control during N ↔ R and N ↔ D static shifting. It is an object of the present invention to provide a hydraulic control device of an 8-speed automatic transmission for a vehicle that can improve transmission shock and improve a fail safe function, thereby improving the reliability of the automatic transmission.

In order to realize the above object, the present invention, as in claim 1, the first, second, third, fourth clutch (C1) (C2) (C3) (C4) and the first, second brake (B1) which is a friction element (B2), each proportional control solenoid valve on the flow path for supplying / discharging the line pressure selectively supplied from the regulator to the plurality of friction elements and the N, D, R range pressure supplied from the manual valve ( First, second, third, fourth, fifth, and sixth pressure control valves PSV1 to PSV6 and first, second, third, fourth, fifth, and sixth pressure switch valves PSW1 to PSW6 independently controlled by VFS1 to VFS6. To configure the hydraulic control unit,

A first clutch control unit (F) configured to supply a "D" range pressure controlled by the first pressure control valve (PSV1) to the first clutch (C1);

A second clutch control unit (G) configured to supply a "D" range pressure controlled by the second pressure control valve (PSV2) to the second clutch (C2) via a first fail-safe valve (FSV1);

A third pressure configured to supply the line pressure supplied through the fourth pressure switch valve PSW4 to be supplied to the third clutch C3 while being controlled via the first switching valve SW1 and the third pressure control valve PSV3. A clutch control unit H;

A first brake control unit I configured to be supplied to the first brake B1 by the “D” range pressure supplied through the third pressure switch valve PSW3 and controlled by the fourth pressure control valve PSV4; ;

The line pressure supplied through the sixth pressure switch valve PSW6 is controlled by the fifth pressure control valve PSV5 to be supplied to the second brake B2 through the second switching valve SW2. A second brake control unit J configured to supply the R range pressure supplied through the first switching valve SW1 to the second brake B2;

The “D” range pressure supplied through the fifth pressure switch valve PSW4 is controlled by the sixth pressure control valve PSV6 to be supplied to the fourth clutch C4 through the second fail safe valve FSV2. It provides a hydraulic control device for an eight-speed automatic transmission for a vehicle, characterized in that comprises a formed fourth clutch control unit (K).

The first, second, and third proportional control solenoid valves VFS1, VFS2, and VFS3 are formed of normal / high type proportional control solenoid valves, and fourth, fifth, and sixth proportional control solenoid valves. (VFS4) (VFS5) and (VFS6) are characterized by being formed as a normal / low type proportional control solenoid valve.

The first fail safe valve FSV1 may be a line pressure, an operating pressure of the first clutch C1, an operating pressure of the third clutch C3, or a first brake B1, a second brake B2, or a fourth pressure. It is characterized in that the operating pressure of the clutch (C4) is formed to be supplied to the control pressure through the four paths.

The first switching valve SW1 is characterized in that the control pressure and the R range pressure of the on / off solenoid valve (SS-A) can be supplied to the control pressure through the two paths.

The second switching valve (SW2) is characterized in that it is formed so that the operating pressure of the N / D range pressure and the third clutch (C3) or the first brake (B1) can be supplied to the control pressure through two paths. do.

The second fail-safe valve (FSV2) is characterized in that the line pressure and the operating pressure of the third clutch (C3) or the first brake (B1) can be supplied to the control pressure through two paths. .

According to the hydraulic control device of the present invention configured as described above, by operating the second brake (B2) in the N, P range, only one friction element (clutch or brake) during N ↔ R, N ↔ D static shift By being controlled, the shift shock can be minimized.

When the failure occurs while driving forward, the hydraulic pressure supplied to the third clutch C3 is interrupted by the operation of the first switching valve SW1, so that the first and second clutches C1 and C2 operate. As it locks into the inside, the fail-safe function becomes more stable, which improves the confidence in the automatic transmission.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a control system diagram of a hydraulic control apparatus according to the present invention. In FIG. 1, a line pressure controller for controlling a hydraulic pressure supplied from an oil pump at a constant pressure, and a torque increase of a torque converter and control of engagement and release of a damper clutch. And a first decompression control unit for reducing the line pressure supplied from the line pressure control unit with a first reducing valve to supply the control pressure of the first, second, third, fourth, fifth and sixth proportional control solenoid valves. And depressurize the line pressure supplied from the line pressure controller with a second reducing valve to control the pressure switch valve and the on / off solenoid valve respectively applied to the first, second, third, fourth, fifth, and sixth proportional control solenoid valves. The well-known structure like the 2nd pressure reduction control part which supplies by pressure, and the manual shift control part which switches a flow path according to a range conversion of a driver is not shown in figure.

In addition, although the manual valve of the manual transmission part which performs a range conversion at the driver's intention is abbreviate | omitted, N, D, and R range pressures in description are supplied through a manual valve as known, and a line pressure is fixed by a regulator valve not shown. The pressure is controlled to mean the pressure supplied to the manual valve.

And the hydraulic control device according to the present invention includes a first clutch control unit (F) for operating in the forward 1,2,3,4 speed and R range;

A second clutch control unit (G) operating at forward 4, 5, 6, 7, and 8 speeds;

A third clutch control unit (H) operating at forward 3, 5 speed and R range;

A fourth clutch control section I operating at six forward speeds;

A first brake control unit (J) operating at forward two, seventh speeds;

And a second brake control part K operating at 8 forward speeds and L, R, N, and P ranges.

In more detail, the first clutch controller F may include a first pressure control valve PCV1 and a first pressure switch valve PSW1 in which a “D” range pressure is controlled by the first proportional control solenoid valve VFS1. It is formed so that it can be supplied directly to the operating pressure of the first clutch (C1) by controlling.

In addition, the second clutch control unit G controls the “D” range pressure in the second pressure control valve PCV2 and the second pressure switch valve PSW2 under the control of the second proportional control solenoid valve VFS2. When supplied to the fail-safe valve FSV1, the first fail-safe valve FSV1 is formed to supply the hydraulic pressure to the second clutch C2 while the flow path is converted by the control pressure supplied through four paths. .

In the above, the control pressure of the first fail-safe valve FSV1 is supplied with a line pressure to one side, and the operating pressure of the first clutch C1, the third clutch C3, or the first brake B1 to the opposite side. ), The operating pressure of the second brake B2 or the fourth clutch C4 is supplied as the control pressure.

The third clutch control unit H has a line pressure controlled by the fourth pressure switch valve PSW4 under the control of the fourth proportional control solenoid valve VFS4, and thus the third pressure control valve through the first switching valve SW1. When supplied to the PSV3, the third pressure control valve PSV3 and the third pressure switch valve PSW3 are controlled by the third proportional control solenoid valve VFS3 to be supplied to the third clutch C3. do.

The first switching valve SW1 is controlled by the on / off solenoid valve SS-A at the forward 3, 5 speed and the L range while supplying the operating pressure to the third clutch C3 and at the same time in the R range. The R range pressure is supplied to the second brake B2 through the second switching valve SW2 applied to the second brake control unit J while being controlled by the R range pressure supplied from a manual valve (not shown).

When the "D" range pressure is controlled by the third pressure switch valve PSW3 under the control of the third proportional control solenoid valve VFS3 and supplied to the fourth pressure control valve PSV4, the first brake controller I is supplied. The fourth proportional control solenoid valve VFS4 is configured to be controlled and supplied from the fourth pressure control valve PSV4 and the fourth pressure switch valve PSW4.

In addition, the second brake controller J may control the sixth pressure switch valve PSW6 according to the control of the sixth proportional control solenoid valve VFS6 at the eighth forward speed and the L range. When supplied to the PSV5, it is controlled by the fifth proportional control solenoid valve VFS5 from the fifth pressure control valve PSV5 and the fifth pressure switch valve PSW5 and supplied to the second switching valve SW2. The second switching valve SW2 is formed to supply the hydraulic pressure to the second brake B2 while the flow path is converted by the control pressure supplied to the two paths.

In addition, in the reverse shift stage, the R range pressure supplied from the first switching valve SW1 is supplied to the second brake B2 through the second switching valve SW2.

As the control pressure of the second switching valve SW2, the operating pressure and the N / D range pressure of the third clutch C1 or the first brake B1 are supplied.

When the "D" range pressure is controlled by the fifth pressure switch valve PSV5 under the control of the fifth proportional control solenoid valve VFS5 and supplied to the sixth pressure control valve PSV6, The sixth proportional control solenoid valve VFS6 is controlled by the sixth pressure control valve PSV6 and the sixth pressure switch valve PSW6 to be supplied to the second fail safe valve FSV2, and the second fail safe valve is provided. (FSV2) is formed so that the oil pressure can be supplied to the fourth clutch (C4) while the flow path is converted by the control pressure supplied through the two paths.

The line pressure is supplied to one side as the control pressure of the second fail-safe valve FSV2, and the operating pressure of the third clutch C3 or the first brake B1 is supplied to the opposite side.

In the above, the first, second, and third proportional control solenoid valves VFS1, VFS2, and VFS3 are N / H types that maintain high when normal and fourth, fifth, and sixth proportional control solenoid valves. VFS4, VFS5, and VFS6 are N / L types that maintain a low level during normal.

First, second, third, fourth, fifth, and sixth proportional control solenoid valves VFS1 to VFS6 are respectively independently controlled by the first, second, third, fourth, fifth, and sixth pressure control valves PSV1 to PSV6. Since the configuration and control process of the first, second, third, fourth, fifth, and sixth pressure switch valves PSW1 to PSW6 are well-known contents, detailed descriptions thereof will be omitted.

The N ↔ R, N ↔ D static shifts and the first and second fail-safe valves (FSV1) (FSV2) for switching the flow path in case of failure, and the configuration of the first and second switching valves (SW1) (SW2) in more detail Looking at it as follows.

First, referring to the configuration of the first fail-safe valve FSV1 applied to the second clutch controller G, as shown in FIG. 2, the first fail-safe valve FSV1 is controlled by the control pressure flowing into four paths. The control is configured to supply the operating pressure to the second clutch (C2).

The first fail-safe valve FSV1 includes a valve body and a valve spool as a spool valve, and the valve body includes a first port 111 that receives a part of the operating pressure of the first clutch C1 as a control pressure. The operating pressure of the second port 112 which receives the operating pressure of the fourth clutch C4 or the second brake B2 as the control pressure, and the operating pressure of the third clutch C3 or the first brake B1 is controlled. The third port 113, the fourth port 114 receives hydraulic pressure from the second pressure control valve PSV2, and the hydraulic pressure supplied to the fourth port 114 are supplied to the second clutch C2. Including a fifth port 115 for supplying the gas, a sixth port 116 for supplying the line pressure as a control pressure, and a seventh port 117 for discharging the hydraulic pressure supplied to the fifth port 115. Is done.

  The valve spool embedded in the valve body as described above includes a first land 121 acting on the control pressure of the first port 111 and a second land 122 acting on the control pressure of the second port 112. ), A third land 123 acting on the control pressure of the third port 113, and a fourth port selectively acting on the fourth port 114 while acting on the control pressure of the sixth port 116. And a fourth land 124 communicating with the 115 and a fifth land 125 acting on the control pressure of the sixth port 116.

Accordingly, the hydraulic pressure supplied from the second pressure control valve PSV2 is controlled while being controlled by the control pressures supplied to the first, second, and third ports 111, 112, 113, and the sixth port 116. 2 to supply the operating pressure of the clutch (C2).

In particular, in the event of a failure of the automatic transmission, the valve spool moves to the right in the drawing due to the line pressure supplied to the sixth port 116 to communicate the fourth and fifth ports 114 and 115 so that the second clutch C2 Allow working pressure to be supplied.

In addition, the second fail-safe valve FSV2 for switching the hydraulic pressure supplied to the fourth clutch C4 includes a valve body and a valve spool as a spool valve.

That is, the valve body is positioned at both ends and the first and second ports 131 and 132 to receive the line pressure as the control pressure, and the third to receive the "D" range pressure from the sixth pressure control valve PSV6. Operation of the port 133, the fourth port 134 for supplying the hydraulic pressure supplied to the third port 133 to the fourth clutch C4, and the third clutch C3 or the first brake B1. And a fifth port 135 that receives pressure and a sixth port 136 that discharges the hydraulic pressure of the fourth port 134.

The valve spool embedded in the valve body may selectively include a first land 141 acting on the control pressure of the first port 131 and a fourth port 134 together with the first land 141. And a second land 142 communicating with the six ports 133 and 136, and a third land 143 acting on the control pressure of the second port 132. It includes an elastic member 144 disposed between the 143 and the valve body.

Accordingly, while the flow path is switched by the control pressure supplied through the first and second ports 131 and 132, the hydraulic pressure supplied to the third port 133 is supplied to the fourth clutch C4.

The first switching valve SW1 applied to the third clutch control unit H includes a valve body and a valve spool as a spool valve, and the configuration thereof is as shown in FIG. 4.

That is, the valve body may include a first port 151 supplied with the control pressure from the on / off solenoid valve SS-A, and second and third ports 152 and 153 supplied with the R range pressure as the control pressure. A fourth port 154 for supplying the hydraulic pressure supplied to the third port 153 to the second switching valve SW2 and a fifth port for discharging the hydraulic pressure supplied to the fourth port 154 ( 155, a sixth port 156 that receives the hydraulic pressure from the fourth pressure switch valve PSV4, and a seventh that supplies the hydraulic pressure supplied to the sixth port 156 to the third pressure control valve PSV3. And a eighth port 158 for discharging the hydraulic pressure supplied to the seventh port 157.

The valve spool embedded in the valve body has a first land 161 acting on the control pressure of the first port 151 and a second land 162 acting on the control pressure supplied to the second port 152. ), A third land 163 for selectively communicating the fourth port 154 with the third port 153 and the fifth port 155 together with the second land 162, and the third land. And a fourth land 164 for selectively connecting the seventh port 157 to the sixth port 156 and the eighth port 158 together with the reference numeral 163, and the fourth land 164. And an elastic member 165 disposed between the valve body and the valve body.

Accordingly, the hydraulic pressure supplied to the third port 153 is selectively supplied to the second switching valve SW2 through the fourth port 154, and the hydraulic pressure supplied to the sixth port 156 is supplied to the seventh port 137. ) Is supplied to the third pressure control valve PSV3.

The second switching valve SW2 includes a valve body and a valve spool as a spool valve, and the configuration thereof is as shown in FIG. 4.

That is, the valve body is located at both ends, the first and second ports 171 and 172 to receive the N, D range pressure as a control pressure, and the third port to receive hydraulic pressure from the fifth pressure control valve PSV5. 173, a fourth port 174 that receives the R range pressure from the first switching valve SW1, and a hydraulic pressure supplied to the third and fourth ports 173 and 174 to selectively supply a second brake ( And a fifth port 175 supplied to B2) and a sixth port 176 supplied with the operating pressure of the third clutch C3 or the first brake B1 as the control pressure.

The valve spool embedded in the valve body may selectively include a first land 181 acting on the control pressure of the first port 171 and a fifth port 175 together with the first land 181. And a second land 182 communicating with the four ports 173 and 174, and a third land 183 formed in connection with the second land 182. 183 and an elastic member 184 disposed between the valve body.

Accordingly, the hydraulic pressure supplied to the third port 173 and the fourth port 174 is selectively supplied to the second brake B2.

In the hydraulic control device configured as described above, as shown in FIG. 5, the first clutch C1 and the one-way clutch not shown operate at the first forward speed, and the first clutch C1 and the first brake at the second forward speed. The first clutch C1 and the third clutch C3 operate at the third forward speed, the first clutch C1 and the second clutch C2 at the fourth forward speed, and at the fifth forward speed. The second clutch C2 and the third clutch C3 operate, and the second clutch C2 and the fourth clutch C4 operate at the sixth forward speed, and the second clutch C2 and the first brake at the seventh forward speed. (B1) is operated, the second clutch (C2) and the second brake (B2) is operated at the eighth forward speed, and the third clutch (C3) and the second brake (B2) is operated at the reverse shift stage, the shift is made. In the N and P ranges, only the second brake B2 is operated.

The second brake B2 is operated in the N and P ranges during the shift as described above, so that only one friction element is controlled during N → R, R → N static shift, thereby minimizing shift shock. I would have to.

That is, when switching to the R range for reversing in the N range, since the second brake B2 is operated in the N range, only the third clutch C3 needs to be operated, and conversely, switching from the R range to the N range. In this case, the operation of the third clutch C3 may be cancelled.

 When switching to the D range for driving in the N range, only the first clutch C1 may be operated and controlled while the second brake B2 is operating. In this case, during the normal forward driving, the second brake B2 is dared. Since there is no need to operate the one-way clutch (not shown) even if the release control is performed to perform the function of the second brake (B2).

In addition, a failure of the automatic transmission may occur due to an abnormality of the electric system. If a failure occurs in the reverse state, the valve spool is supplied to the second port 152 of the first switching valve SW while The R range pressure supplied to the third port 153 by moving to the left is supplied to the fourth port 174 of the second switching valve SW2 through the fourth port 154.

Then, the second switching valve SW2 is moved to the left side in the drawing by the elastic force of the elastic member 184 to communicate with the fourth cloth 174 and the fifth port 175 to the second brake B2. By supplying the working pressure, the operating state is maintained.

The first switching valve SW1 of the valve spool is moved to the left side in the drawing due to the R range pressure. As a result, the sixth port 156 and the seventh port 158 communicate with each other, whereby the fourth switch valve PSW4. Line pressure is supplied through the third pressure control valve (PCV3) is supplied, wherein the third proportional control solenoid valve (VFS3) for controlling the third pressure control valve (PCV3) of the bar is made of N / H type As the line pressure is continuously supplied to the third clutch C3, the reverse shift stage at which the third clutch C3 and the second brake B2 operate is maintained.

If the automatic transmission fails during the forward driving, since the fourth, fifth and sixth proportional control solenoid valves VFS4, VFS5 and VFS6 are N / L type, the hydraulic supply to the downstream side is cut off and the first and second The brakes B1 and B2 and the fourth clutch C4 are not operated.

However, the first, second, and third proportional control solenoid valves VFS1, VFS2, and VFS3 are supplied with an N / H type, so that hydraulic pressure is supplied downstream. In this case, the first switch valve SW1 has an elastic member ( The valve spool moves to the right in the figure by the elastic force of 165 to block the sixth port 156 that receives the hydraulic pressure from the fourth pressure switch valve PSW4.

Accordingly, the operation of the third clutch C3 is stopped, and only the first and second clutches C1 and C2 operate, so that forward driving is possible while being fixed at the fourth forward speed.

As described above, the present invention can simplify the control when shifting N → R and R → N to improve the controllability, improve the static impact, and make the fail safe function more stable, You can improve your confidence in.

Although a preferred embodiment of the hydraulic control device of the present invention has been described above, the present invention is not limited to the above embodiment, and those skilled in the art from the embodiment of the present invention easily. Invention includes all modifications to the extent deemed equivalent.

1 is a hydraulic system diagram of the main part of the hydraulic control device according to the present invention.

Figure 2 is a detailed cross-sectional view of the first fail-safe valve applied to the present invention.

3 is a detailed cross-sectional view of a second fail-safe valve applied to the present invention.

4 is a detailed cross-sectional view of the first and second switching valves applied to the present invention.

5 is an operation of each shift stage of the friction element applied to the present invention.

Claims (9)

And a first, second, third, and fourth clutches C1, C2, C3, C4 and first and second brakes B1, B2, which are friction elements, and selectively 1, 2, 3 and 4 independently controlled by the proportional control solenoid valves VFS1 to VFS6 on the supply line pressure and the flow paths for supplying / discharging the N, D and R range pressures supplied from the manual valve. 5,6 pressure control valves (PSV1 to PSV6), 1,2,3,4,5,6 pressure switch valves (PSW1 to PSW6) and one on / off solenoid valve (SS-A) Configure a hydraulic control device that can achieve eight speeds, A first clutch control unit (F) configured to supply a "D" range pressure controlled by the first pressure control valve (PSV1) to the first clutch (C1); A second clutch control unit (G) configured to supply a "D" range pressure controlled by the second pressure control valve (PSV2) to the second clutch (C2) via a first fail-safe valve (FSV1); A third pressure configured to supply the line pressure supplied through the fourth pressure switch valve PSW4 to be supplied to the third clutch C3 while being controlled via the first switching valve SW1 and the third pressure control valve PSV3. A clutch control unit H; A first brake control unit I configured to be supplied to the first brake B1 by the “D” range pressure supplied through the third pressure switch valve PSW3 and controlled by the fourth pressure control valve PSV4; ; The line pressure supplied through the sixth pressure switch valve PSW6 is controlled by the fifth pressure control valve PSV5 to be supplied to the second brake B2 through the second switching valve SW2. A second brake control unit J configured to supply the R range pressure supplied through the first switching valve SW1 to the second brake B2; The “D” range pressure supplied through the fifth pressure switch valve PSW4 is controlled by the sixth pressure control valve PSV6 to be supplied to the fourth clutch C4 through the second fail safe valve FSV2. Hydraulic control device for an eight-speed automatic transmission for a vehicle comprising a fourth clutch control unit (K) formed. The first fail-safe valve FSV1 may include a line pressure, an operating pressure of the first clutch C1, an operating pressure of the third clutch C3 or the first brake B1, and a second brake B2. Or an operating pressure of the fourth clutch C4 to be supplied to the control pressure through four paths. The first failsafe valve FSV1 of claim 1 or 2, wherein the first fail safe valve FSV1 is provided with a first port 111 and a fourth clutch C4 or a part of the operating pressure of the first clutch C1 as a control pressure. The second port 112 receives the operating pressure of the second brake B2 as the control pressure, and the third port 113 receives the operating pressure of the third clutch C3 or the first brake B1 as the control pressure. ), A fourth port 114 that receives the hydraulic pressure from the second pressure control valve PSV2, and a fifth port 115 that supplies the hydraulic pressure supplied to the fourth port 114 to the second clutch C2. A valve body including a sixth port 116 for supplying line pressure as a control pressure, and a seventh port 117 for discharging hydraulic pressure supplied to the fifth port 115; The first land 121 acting on the control pressure of the first port 111, the second land 122 acting on the control pressure of the second port 112, and the third port 113 The third land 123 acting on the control pressure, and the fourth land selectively communicating the fourth port 114 with the fifth port 115 while acting on the control pressure of the sixth port 116 ( 124 and a valve spool comprising a fifth land (125) acting on the control pressure of the sixth port (116). The method of claim 1, wherein the first switching valve (SW1) is characterized in that the control pressure and the R range pressure of the on / off solenoid valve (SS-A) can be supplied to the control pressure through the two paths Hydraulic control system for 8-speed automatic transmission for vehicles. 5. The first switching valve SW1 of claim 1, wherein the first switching valve SW1 supplies the first port 151 supplied with the control pressure from the on / off solenoid valve SS-A and the R range pressure as the control pressure. Receiving second and third ports 152 and 153, a fourth port 154 for supplying hydraulic pressure supplied to the third port 153 to the second switching valve SW2, and the fourth port ( The fifth port 155 for discharging the hydraulic pressure supplied to the 154, the sixth port 156 receiving the hydraulic pressure from the fourth pressure switch valve PSW4, and the hydraulic pressure supplied to the sixth port 156 A valve body comprising a seventh port 157 for supplying to the third pressure control valve PSV3 and an eighth port 158 for discharging hydraulic pressure supplied to the seventh port 157; A first land 161 acting on the control pressure of the first port 151, a second land 162 acting on the control pressure supplied to the second port 152, and the second land 162. A third land 163 for selectively communicating the fourth port 154 with the third port 153 and the fifth port 155, and a seventh port with the third land 163. An elastic member disposed between the fourth land 164 and the valve body, wherein the fourth land 164 communicates with the sixth port 156 and the eighth port 158. Hydraulic control device for an eight-speed automatic transmission for a vehicle comprising a valve spool consisting of (165). The second switching valve SW2 is configured such that the N / D range pressure and the operating pressure of the third clutch C3 or the first brake B1 can be supplied to the control pressure through two paths. Hydraulic control device for a vehicle 8-speed automatic transmission characterized in that. The first and second ports 171 and 172 of claim 1 or 6, wherein the second switching valve SW2 is disposed at both ends and receives N, D range pressure as a control pressure. The third port 173 receiving hydraulic pressure from the control valve PSV5, the fourth port 174 receiving the R range pressure from the first switching valve SW1, and the third and fourth ports 173 ( The fifth port 175 selectively supplying the hydraulic pressure supplied to the second brake B2, and the sixth receiving the operating pressure of the third clutch C3 or the first brake B1 as the control pressure. A valve body comprising a port 176; A first land 181 acting on the control pressure of the first port 171 and a fifth port 175 together with the first land 181 may be selectively selected by the third and fourth ports 173 and 174. And a second land 182 communicating with the second land 182 and a third land 183 formed in connection with the second land 182 and disposed between the third land 183 and the valve body. Hydraulic control device for an eight-speed automatic transmission for a vehicle including a valve spool made of an elastic member (184). The second fail-safe valve FSV2 is configured such that the line pressure and the operating pressure of the third clutch C3 or the first brake B1 can be supplied to the control pressure through two paths. Hydraulic control device for a vehicle 8-speed automatic transmission characterized in that. The second fail-safe valve FSV2 is positioned at both ends and receives first and second ports 131 and 132 that supply line pressure as a control pressure, and the sixth pressure control valve. A third port 133 to receive the "D" range pressure from the PSV6, a fourth port 134 to supply hydraulic pressure supplied to the third port 133 to the fourth clutch C4, and A valve body comprising a fifth port 135 supplied with the operating pressure of the third clutch C3 or the first brake B1, and a sixth port 136 for discharging the hydraulic pressure of the fourth port 134; A first land 141 acting on the control pressure of the first port 131 and a fourth port 134 together with the first land 141 may be selectively selected by the third and six ports 133 and 136. And a second land 142 communicating with the third land 143 and a third land 143 acting on the control pressure of the second port 132, and disposed between the third land 143 and the valve body. Hydraulic control device for an 8-speed automatic transmission for a vehicle comprising a valve spool made of an elastic member (144).

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