KR100357593B1 - Hydraulic control system for automatic transmission - Google Patents

Abstract

The accumulator control means for controlling the accumulator is added to the valve body so that the accumulator can be used in common for two or more friction elements without changing the electronic control or the transmission case. To provide a hydraulic control system that minimizes shift shock during power-off or manual shifting without the addition of accumulators that must be changed.

With the engine started, the hydraulic pressure generated from the oil pump is regulated to a constant pressure by the regulator valve, partly supplied to the working pressure of the damper clutch and the reducing valve, and the other part selectively to the friction elements operating at each shift stage. In order to supply the operating pressure is made to be supplied to the hydraulic control unit including the shift control means, pressure control means, switching means, fail safe means, NR control means,

The hydraulic control system for a vehicle, characterized in that the one side of the hydraulic control unit further comprises an accumulator control means to selectively connect two or more operating pressures for operating the friction element to one accumulator to be used in common.

Description

HYDRAULIC CONTROL SYSTEM FOR AUTOMATIC TRANSMISSION}

The present invention relates to a hydraulic control system applied to a vehicle automatic transmission to control the hydraulic pressure.

For example, an automatic transmission for a vehicle has a torque converter and a power train, which is a multi-stage 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 system for operation.

In designing such automatic transmission, conceptual design and design plan are presented first to find a design concept that meets the design goal, and select one of the best design concepts in terms of performance, durability, reliability, mass production, and manufacturing cost. Done.

When the design concept as described above is selected, the development is usually divided into three parts: a mechanical section, a hydraulic control system, and an electronic control system.

The power train in the mechanical section is composed of a composite planetary gear set that can achieve the required shift stage by combining four or more simple planetary gear sets of four, and the hydraulic control system operating the power train is an oil pump. Pressure control means for adjusting the oil pressure generated from the manual, manual and automatic shift control means for forming a shift mode, hydraulic control means for adjusting the shifting feeling and responsiveness to form a smooth shift mode during shifting, and the hydraulic control Hydraulic distribution means for appropriately distributing the hydraulic pressure supplied from the means to each friction element, and damper clutch control means for operating the damper clutch of the torque converter.

Accordingly, the hydraulic distribution of the hydraulic distribution means is made different by the solenoid valves turned on / off by the transmission control unit and the solenoid valves controlled by the duty, and the operation of the friction element is selected to realize the shift stage control.

However, in the hydraulic control system of the conventional automatic transmission, although the accumulator is configured on the hydraulic line for supplying hydraulic pressure to some friction elements, it is possible to improve the feeling of shifting. There is a problem that the layout of the entire transmission affected by the layout, that is, the transmission case is difficult without deformation, and that there is a limit to the improvement of the transmission feeling only by electronic control.

Accordingly, the present invention has been invented to solve the above problems, and an object of the present invention is to use an accumulator that has been previously applied and used for two or more friction elements without changing the electronic control or the transmission case. By adding the accumulator control means for controlling the accumulator in the valve body, to provide a hydraulic control system that can minimize the shift shock during power-off or manual shifting without adding the accumulator to change the layout of the entire transmission .

1 is a block diagram of a power train to which the present invention is applied.

Figure 2 is a friction element operating table of the power train to which the present invention is applied.

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

Figure 4 is a block diagram of the hydraulic control means applied to the present invention.

5 is a block diagram of distribution means for switching means, fail safe means, and N-R control means applied to the present invention;

6 is a block diagram of an accumulator control means applied to the present invention.

7 is a view showing a hydraulic flow state of the parking (P) range in the hydraulic control system according to the present invention.

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

Fig. 9 is a diagram showing a hydraulic flow state in the running (D) range 2 speed in the hydraulic control system according to the present invention.

10 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.

11 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.

12 is a view showing a hydraulic flow state in the L range in the hydraulic control system according to the present invention.

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

In order to realize this, the present invention, the hydraulic pressure generated from the oil pump with the start of the engine is regulated to a constant pressure by the regulator valve, a part is supplied to the operating pressure and the reducing valve of the damper clutch, the other part of each gear stage In order to selectively supply the operating pressure to the friction element to operate in the hydraulic control including a shift control means, pressure control means, switching means, fail-safe means, NR control means,

One side of the hydraulic control unit further comprises an accumulator control means to selectively connect two or more operating pressures for operating the friction element to one accumulator to be used in common,

The shift control means is made of a manual valve in communication with a plurality of conduits to supply hydraulic pressure through each range conduit while being linked to the driver's select lever operation,

The pressure control means may be independently controlled by the first, second and third solenoid valves for controlling the control pressure supplied from the reducing valve and the control pressure supplied from the first, second and third solenoid valves. It consists of the first, second, third pressure control valve for controlling the hydraulic pressure supplied from the valve,

The switching means includes a friction between the first switch valve for selectively supplying the hydraulic pressure supplied from the first pressure control valve to two flow paths, the hydraulic pressure supplied from the third pressure control valve and the hydraulic pressure supplied from the manual valve. A second switch valve for supplying to the second switch valve for supplying to the urea,

The fail-safe means includes a first fail safe valve for supplying the hydraulic pressure supplied from the first switch valve and the manual valve to a friction element operated at low speed and backward, and the second and fourth speeds for the hydraulic pressure supplied from the second pressure control valve. A second fail-safe valve for supplying to the friction element operating at

The N-R control means is composed of an N-R control valve for controlling the reverse pressure to supply to the clutch operating only in the reverse shift stage,

The accumulator control means is controlled by the hydraulic pressure supplied from the manual valve and is supplied to the corresponding clutch from the second switch valve in the forward 2, 3 speed, 2 range 2 speed, 3 range 2, 3 speed and L range. It provides an automatic transmission hydraulic control system for a vehicle, characterized in that it consists of an accumulator switch valve that selectively connects the accumulator to shock pressure relief and shock relief of the operating pressure supplied from the NR control valve to the clutch when reversing. do.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described in detail.

1 is a configuration diagram of a power train to which the hydraulic control system of the present invention is applied, and FIG. 2 is a friction element operating table of a power train to which the present invention is applied, and the power train thereof is a combination of two single-pinion planetary gear sets. It is designed to obtain a shift stage of 4 forward speeds and 1 reverse speed.

That is, when rotational power from the engine 2 is transmitted to the input shaft 6 via the torque converter 4, the input shaft 6 is torqued to the first and second single pinion planetary gear sets 8 and 10. And shifting is performed by the complementary operation of these first and second single pinion planetary gear sets 8 and 10 and connected to the planet carrier 12 of the first single pinion planetary gear set 8. There is a clutch hook-up that can be output through the transfer drive gear 14.

(Hereinafter, in order to avoid repeating the first and second single pinion planetary gear sets 8 and 10, the sun gear 16, the planet carrier 12, and the ring gear 18 of the first single pinion planetary gear set. Are referred to as the first sun gear 16, the first planet carrier 12, and the first ring gear 18, and the sun gear 20, the planet carrier 22, and the ring gear 24 of the second single-pinion planetary gear set. ) Is referred to as the second sun gear 20, the second planet carrier 22, and the second ring gear 24.

Looking at the connection relationship between the first and second single pinion planetary gear sets 8 and 10, the first sun gear 16 is fixed to the second ring gear 24 while the first planet carrier 12 is fixedly connected to the second ring gear 24. Is connected to the input shaft 6 via the first friction element C1 operating in all regions of the forward shift stage.

In addition, the second planet carrier 22 is connected to the input shaft 6 via the second clutch C2 operating at the forward third and fourth speeds, and the second sun gear 20 is the third clutch operating at the reverse shift stage. It is connected with the input shaft 6 via C3.

In addition, the second planet carrier 22 is connected to the transmission housing 26 through a first brake B1 and a first one-way clutch F1 arranged in parallel and parallel with the first ring gear 18. The fourth clutch C4 and the second one-way clutch F2 are disposed to be connected to each other.

In addition, the second sun gear 20 has a configuration in which the second sun gear 20 is connected to the transmission housing 26 via the second brake B2.

Looking at the shift operation of the power train as described above, the first clutch (C1) and the fourth clutch (C4) and the first and second one-way clutch (F1) (F2) in the first forward speed, the first sun gear ( 16 acts as an input element and the first ring gear 18 and the second planet carrier 22 act as a reaction element.

In the second forward speed, the second brake B2 is operated in the state of the first speed, so that the second sun gear 20 operates as a reaction force element while the second sun gear 20 is input to the first sun gear 18.

At the third forward speed, the second clutch C2 is operated in the state of the second speed, and the operation of the second brake B2 is released, whereby the first and second single pinion planetary gear sets 8 and 10 are locked while being input. At the same speed as the output.

In the fourth forward speed, the second brake B2 operates in the third speed state, so that the reaction force becomes the second sun gear 20 and shifts to the fourth speed in the overdrive state.

In the reverse shift stage, when the third and fourth clutches C3 and C4 and the first brake B1 are operated to be input to the second sun gear 20, the second planet carrier 22 becomes a reaction element and moves backward. The shift is made.

3 shows a hydraulic control system for controlling the respective friction elements C1, C2, C3, C4, B1, and B2 of the power train as described above, wherein the select lever is in the neutral (N) range. The state when it is in is shown, and the same code | symbol is attached | subjected to the same part as the said power train.

When the torque converter 4 that receives the power from the engine 2 and converts the torque and transmits the torque to the transmission side is operated, the oil pump 100 is operated to perform hydraulic pressure and lubrication necessary for the torque converter 4 and the shift stage control. Hydraulic pressure is generated, and the hydraulic pressure generated from the oil pump 100 is supplied to the hydraulic control means through the manual and automatic shift control means for forming a shift mode while being supplied to the pressure regulating and damper clutch control means and the decompression means. It is controlled by hydraulic pressure suitable for shifting, and the controlled pressure is supplied to the operating pressure of each friction element through the switching means and the fail-safe means, and in the reverse range, it is directly transferred from the manual and control means to the friction element through the NR control means. It is supplied to a hydraulic control unit configured to be supplied.

In addition, the hydraulic control unit may be supplied with the hydraulic pressure generated from the oil pump 100, including an accumulator control means to selectively connect two or more operating pressures for operating the friction element to one accumulator for common use. Is done.

The pressure regulating and damper clutch control means is a regulator valve 102 for regulating the hydraulic pressure fed from the oil pump 100 to a constant pressure, and the hydraulic pressure supplied from its regulator valve 102 for torque converter and lubrication constantly Torque converter control valve 104 to adjust, and damper clutch control valve 106 to control the damper clutch to increase the power transmission efficiency of the torque converter.

The decompression means is composed of a reducing valve 108 to maintain a pressure lower than the line pressure at all times, a portion of the hydraulic pressure reduced through the reducing valve 108 of the control of the damper clutch control valve 106 At the same time as the pressure is supplied to the control pressure of the regulator valve (102).

The first and second pressure reducing valves 110, 112, and 114 form a hydraulic pressure that may be used as a shift stage control pressure, and the first, second and third solenoid valves controlling them. It is supplied to the pressure control means which consists of S1) (S2) (S3).

The shift control means for forming the manual and automatic shift mode is composed of a manual valve 116 for switching the flow while operating in conjunction with the position of the selector lever in the driver's seat, the hydraulic pressure supplied to the manual valve 116 is The first and second switch valves 118 and 120 of the switching means, which are supplied to the pressure control means or disposed directly downstream according to each range selection, and the first and second fail safe valves 122 of the fail safe means. 124, the control pressure of the NR control valve 126, which is the NR control means, or is supplied to the corresponding friction element via the control pressure.

And the accumulator control means is composed of an accumulator switch valve 501 controlled by the hydraulic pressure supplied from the manual valve 116, the 2nd speed forward, 3rd speed, 2 range 2 speed, 3 range 2, 3 speed and L range At the time, the operating pressure supplied from the second switch valve 120 to the fourth clutch C4 and the operating pressure supplied from the NR control valve 126 to the third clutch C3 at the time of reversing the existing third clutch ( Optionally connected to the accumulator 500 for C3) is configured to be common to effectively mitigate the shift shock.

As such, in constructing the hydraulic control system, the manual valve 118 is configured as shown in FIG. 4, the manual valve 116 of which is connected to the regulator valve 102 via a line pressure line 126. When the hydraulic pressure is supplied, manual shift is supplied through the N range pressure pipeline 130, the D range pressure pipeline 128, the L range pressure pipeline 132, and the “R” range pressure pipeline 134 according to each range. Done.

In the above, the N range pressure line 130 is supplied to and controlled by the first pressure control valve 110 and communicated to be supplied at the control pressure of the second fail-safe valve 124, and the D range pressure line 128 is provided. Is controlled to be supplied to the second and third pressure control valves 112 and 114 and to be supplied at the same time as the control pressure of the first and second switching valves 118 and 120, and the L range pressure pipeline 132 is connected thereto. Is communicated to supply a control pressure of the first switch valve 118, and the "R" range pressure line 134 is communicated to be supplied to the ND control valve 126 and the regulator valve 102.

And the configuration of the first pressure control valve 110 and the first solenoid valve (S1) forming the hydraulic control means, as shown in Figure 4, the valve body of the first pressure control valve 110 is a reducing valve The first port 150 receives hydraulic pressure reduced from 108, the second port 152 supplied hydraulic pressure from the manual valve 116, and the hydraulic pressure supplied to the second port 152. And a third port 154 supplied to the switching valve 118 and a fourth port 156 supplied with a control pressure from the first solenoid valve S1.

The valve spool embedded in the valve body has a hydraulic pressure supplied to the first port 150, a first land 158 having a small diameter, and a hydraulic pressure supplied to the first port 150. And a second land 160 for selectively opening / closing the second port 152, and a second port 152 and a third port 154 selectively communicating with the second land 160. 3 land 162 is formed, and the elastic member 164 is disposed between the third land 162 and the valve body to always maintain the valve spool is always moved to the left in the drawing.

The first solenoid valve S1 for controlling the first pressure control valve 110 as described above is a three-way valve, and when turned on, the supply of the reduced pressure hydraulic pressure is blocked. When the hydraulic pressure supplied at the control pressure is discharged and, on the contrary, off-controlled, the discharge port is closed and the valve holds a flow path through which the reduced pressure hydraulic pressure can be supplied to the first pressure control valve 110. Therefore, it will be omitted.

When the first solenoid valve S1 is turned on according to the above configuration, the supply of the control pressure to the fourth port 156 is cut off, whereby the first pressure control valve may be formed by the reducing pressure supplied to the first port 150. The valve spool of 110 is moved to the right in the drawing to close the second port 152, and if the control is turned off, the valve spool is moved to the left in the drawing while the control pressure is supplied to the fourth port 156. The second port 152 and the third port 154 communicate with each other to supply hydraulic pressure to the first switching valve 120.

In addition, the valve body of the second pressure control valve 112 may include a first port 170 receiving hydraulic pressure reduced from the reducing valve 108 and a second port 172 receiving hydraulic pressure from the manual valve 116. And a third port 174 for supplying the hydraulic pressure supplied to the second port 172 to the second fail safe valve 124, and a fourth port for receiving control pressure from the second solenoid valve S2 ( 176).

The valve spool embedded in the valve body has a hydraulic pressure supplied to the first port 170, a first land 178 having a small diameter, and a hydraulic pressure supplied to the first port 170. At the same time, the second land 180 for selectively opening and closing the second port 172 and the second port 172 and the third port 174 selectively communicate with the second land 182. A third land 182 is included, and a ballistic member 184 is disposed between the third land 182 and the valve body so that the valve spool is always moved to the left in the drawing.

When the second solenoid valve S2 is turned on according to the above configuration, the supply of the control pressure to the fourth port 176 is cut off, whereby the second pressure control valve is supplied by the reducing pressure supplied to the first port 170. The valve spool of 112 is moved to the right in the drawing to close the second port 172. On the contrary, when the off control is made, the valve spool is moved to the left in the drawing while the control pressure is supplied to the fourth port 176. The second port 172 and the third port 174 communicate with each other to supply hydraulic pressure to the second fail-safe valve 124.

In addition, the valve body of the third pressure control valve 114 may include a first port 190 that receives the reduced pressure from the reducing valve 108 and a second port 192 that receives the oil pressure from the manual valve 116. ), A third port 194 for supplying the hydraulic pressure supplied to the second port 192 to the second switch valve 114, and a fourth port for receiving control pressure from the third solenoid valve S3 ( 196).

The valve spool embedded in the valve body has a hydraulic pressure supplied to the first port 190, a first land 198 having a small diameter, and a hydraulic pressure supplied to the first port 190. At the same time, the second land 200 for selectively opening and closing the second port 192 and the second port 192 and the third port 194 may be selectively communicated with the second land 200. It comprises a third land 202, between the third land 202 and the valve body is provided with a bullet member 204 to always maintain the valve spool is always moved to the left in the drawing.

When the third solenoid valve S3 is turned on by the above configuration, the valve spool of the third pressure control valve 114 is moved to the right side in the drawing to close the second port 192, and conversely, the off control is performed. As the ground control pressure is supplied, the valve spool is moved to the left in the drawing to communicate the second port 192 and the third port 194 to supply the hydraulic pressure supplied from the manual valve 114 to the second switch valve 120. Done.

And as shown in Figure 5, the switching means is applied to the control pressure supplied from the on / off solenoid valve (S4) for communicating / blocking the hydraulic pressure supplied from the manual valve 116 and the hydraulic pressure supplied from the reducing valve 108. It is composed of the first and second switch valves 118 and 120 that are controlled by the port conversion.

In the above, the first switch valve 118 selectively receives the N range pressure supplied from the first pressure control valve 110 through the second clutch C2 and the first fail safe valve 122. Will be supplied.

In addition, the valve body forming the first switch valve 118 includes a first port 210 that receives the N range pressure from the manual valve 116 as a control pressure, and controls the L range pressure from the manual valve 116. The second port 212 supplied through the second port, the third port 214 supplied with the control pressure from the on / off solenoid valve S4, and the fourth port supplied with the hydraulic pressure from the first pressure control valve 110 ( 216, a fifth port 218 for supplying a control pressure of the second clutch C2 and the first and second fail-safe valves 122 and 124 to supply hydraulic pressure to the fourth port 216; The sixth port 220 for supplying the hydraulic pressure supplied to the fourth port 216 to the first fail-safe valve 122, and the hydraulic pressure returned to the fifth port 218 and the sixth port 220 It comprises a first and second discharge port (EX1) (EX2) for discharging.

In addition, the valve spool which is controlled by the hydraulic pressure supplied to the first, second and third ports 210, 212, and 214 and forms a port change acts on the control pressure supplied to the first port 210. A first land 222, a second land 224 selectively communicating the fourth port 218 and a sixth port 220, and optionally the fourth port 218 and the fifth port 218. A third land 226 communicating with the second land, a fourth land 228 acting on the control pressure supplied to the third port, and a fifth land on which the control pressure supplied to the second port 212 operates. 229).

Accordingly, in the forward 1,2,3,4 shift stages, the operating pressure supplied from the first pressure control valve 110 at the third and fourth speeds is controlled by the control pressure supplied to the first port 210. The first brake is supplied to the clutch C2, and the operating pressure supplied from the first pressure control valve 110 is controlled by the control pressure supplied from the second port 212 and the third port 214 in the L range. By converting the flow path so that it can be supplied to (B1), it is possible to prevent the hydraulic pressure from being supplied to the second clutch C2 and the first brake B1 at the same time.

The valve body forming the second switch valve 120 may include a first port 230 that receives the D range pressure from the manual valve 116, and a second that receives the control pressure from the on / off solenoid valve S4. A port 232, a third port 234 supplied with hydraulic pressure from the third pressure control valve 114, a fourth port 236 supplied with line pressure, and a third port 234 supplied to the third port 234. A fifth port 238 for supplying hydraulic pressure to the first clutch C1, a sixth port 240 for supplying hydraulic pressure supplied to the first port 230 to the first clutch C1, and the fifth port 238; A seventh port 242 for supplying the hydraulic pressure supplied to the four ports 236 to the fourth clutch C4 and an eighth for supplying the hydraulic pressure supplied to the third port 234 to the fourth clutch C4 A port 244 and first and second discharge ports EX1 and EX2 for discharging hydraulic pressure returned to the fifth, sixth, seventh and eighth ports 238, 240, 242 and 244, respectively. Is done.

In addition, the valve spool which is controlled by the hydraulic pressure supplied to the first and second ports 230 and 232 and forms a port change acts on the control pressure supplied to the first port 230 and optionally the first port ( First and second lands 246 and 248 that block and communicate with the 230 and the sixth port 240, and a third land that selectively communicates with and blocks the third and fifth ports 234 and 238. And a fourth land 252 for selectively communicating and blocking the third port 234 and the eighth port 244, and the fourth port 236 and the seventh port 242. And a fifth land 254 communicating with and blocking the second land 254, and a sixth land 256 acting on a control pressure supplied to the second port 232.

In addition, a pipe line connected to each of the fifth port 238 and the sixth port 240 communicates with the first clutch C1 through the first shuttle valve 260, and is downstream of the first shuttle valve 260. On the side, the pipe is branched and communicates with the pipe 262 branched from the upstream side of the first port 230 through the first check valve 264, the first check valve 264 is from the upstream to the downstream side. The hydraulic pressure is prevented from flowing.

In addition, the pipe line 262 branched from the upstream side of the first port 230 branches again to allow the first and second fail-safe valves 122 and 124 and the first brake through the second check valve 266. Connected to the operating pressure of B1), the second check valve 266 is configured to prevent hydraulic flow from the upstream side to the downstream side.

In addition, a pipe line connected to each of the seventh port 242 and the eighth port 244 communicates with the fourth clutch C4 through the second shuttle valve 268 and is downstream of the second shuttle valve 268. On the side, the pipe is branched and configured to be supplied at a control pressure of the second fail-safe valve 124.

In the above description, the first and second check valves 264 and 266 are for quickly discharging hydraulic pressure during manual shifting from the D range to the N range, and the first and second shuttle valves 260 and 268 are When the hydraulic pressure is supplied from the second switch valve 120 to the first and fourth clutches C1 and C4, the other port is blocked according to the flow path of the hydraulic pressure.

According to the above configuration, the second switch valve 120 supplies the oil pressure supplied from the third pressure control valve 114 to the fourth clutch C4 at the forward 2nd and 3rd speeds, and is supplied from the manual valve 116. Supply pressure to the first clutch C1, supply line pressure to the fourth clutch C4 while being controlled by the on / off solenoid valve S4 in the N, P, and R ranges, and on / off in the L range. While controlling by the solenoid valve S4, the D-range pressure supplied from the manual valve 116 is supplied to the fourth clutch C4, and the hydraulic pressure supplied from the first pressure control valve 114 is supplied to the first clutch C1. To be supplied.

The first and second fail safe valves 122 and 124 forming the fail safe means are used to prevent the first and second brakes B1 and B2 acting as reaction elements to simultaneously operate. Looking at the configuration of the valve 122, as shown in Figure 5, the valve body is supplied to the first port 280 and the second brake (B2) for receiving the hydraulic pressure supplied to the second clutch (C2) at a control pressure. The second port 282 is supplied from the hydraulic pressure to the control pressure, the third port 284 to receive the line pressure as the control pressure, the R range pressure pipeline 130 and the first switch valve 118 is supplied from A fourth port 288 supplied to the hydraulic pressure through the third shuttle valve 286, and a fifth port 290 for supplying the hydraulic pressure supplied to the fourth port 288 to the third clutch C3. It is done by

The valve spool includes a first land 292 acting on the control pressure supplied to the first port 280, a second land 294 acting on the control pressure supplied to the second port 282, and A third land 296 for selectively communicating the fourth port 288 and the fifth port 290, and a fourth port 288 together with the third land 296 and the fifth port 290. And a fourth land 298 for selectively communicating, and a fifth land 300 acting by a control pressure supplied to the third port 284.

Accordingly, the hydraulic pressure supplied to the first switch valve 118 is supplied to the first brake B1 while being controlled by the line pressure in the N, P, and L ranges, and is supplied from the R range pressure line 130 in the R range. The supplied hydraulic pressure is supplied to the first brake B1.

The valve body of the second fail-safe valve 124 may include a first port 310 through which the R range pressure is supplied as a control pressure, and a second portion through which a part of the hydraulic pressure supplied to the fourth clutch C4 is supplied as the control pressure. A port 312, a third port 314 in which a part of the hydraulic pressure supplied to the second clutch C2 is supplied as the control pressure, a fourth port 316 supplied with the N range pressure as the control pressure, and 2 includes a fifth port 318 for receiving hydraulic pressure from the pressure control valve 112 and a sixth port 320 for supplying the hydraulic pressure supplied to the fifth port 318 to the second brake B2. Is done.

In addition, the valve spool includes a first land 322 to which the control pressure supplied to the first port 310 acts, a second land 324 to which the control pressure supplied to the second port 312 acts, and And a third land 326 to which the control pressure supplied to the third port 314 acts, and a fourth land 328 to selectively communicate the fifth port 318 and the sixth port 320. In addition, the fifth land 330 which communicates the fifth port 318 and the sixth port 320 together with the fourth land 328, and the control pressure supplied to the fourth port 316 acts. And a sixth land 332.

Accordingly, the hydraulic pressure supplied from the second pressure control valve 112 is supplied to the second brake B2 at the second and fourth forward speeds.

In addition, as illustrated in FIG. 5, the NR control valve 126 for reducing the shock during NR manual shifting includes a first port 340 to which the control pressure of the second solenoid valve S2 is supplied, and an R range pressure pipeline 134. The valve body is made of a second port 342 connected to the second port 342 and a third port 344 for supplying the hydraulic pressure supplied to the second port 342 to the third clutch C3. The downstream side of 344 is branched and connected to the R range pressure line 134 through the third check valve 346.

In the above, the third check valve 346 is disposed so that the hydraulic pressure does not flow from the upstream side to the downstream side so that the hydraulic pressure supplied to the third clutch C3 is quickly discharged.

In addition, the valve spool embedded in the valve body may include a first land 348 through which hydraulic pressure flowing into the first port 340 is applied; And a second land 350 for selectively opening and closing the second and third ports 340 and 342, and the second land 252 is interposed between the valve bodies to right the valve spool in the drawing. The elastic member 352 exerts an elastic force so as to be pushed by.

Accordingly, while the NR control valve 126 is controlled by the control pressure supplied from the second solenoid valve S24 in the R range, the NR control valve 126 gradually supplies the hydraulic pressure supplied from the manual valve 116 to the third clutch C3 to shift. The shock can be alleviated.

In addition, in the present invention in forming the line pressure variable means, as shown in Figure 3, by supplying the hydraulic pressure supplied from the reducing valve 108 to the regulator valve 102 to control the line pressure to be made, By placing a solenoid valve (S5) capable of duty control in the middle portion to control the solenoid valve (S5) in accordance with the operating conditions to vary the line pressure to prevent the drive loss of the oil pump 100 due to excessive line pressure Is done.

As the accumulator control means, the accumulator switch valve 501 which enables the accumulator 500 for the third clutch C3 to be shared with the fourth clutch C4 is a manual valve (as shown in FIG. 6). From the first port 503 to receive the R range pressure as a control pressure from the 116, the second port 505 to receive the N range pressure as a control pressure from the manual valve 116, and from the NR control valve 126. A third port 507 for receiving hydraulic pressure, a fourth port 509 for connecting the hydraulic pressure supplied to the third port 507 to the accumulator 500 for the third clutch C3, and a second switch A fifth port 511 to receive hydraulic pressure from the valve 120, a sixth port 513 to receive the D range pressure as a control pressure from the manual valve 116, and a return from the fifth port 511. Composed of a discharge port 515 for discharging the hydraulic pressure to constitute a valve body,

The valve spool embedded in the valve body has a first land 517 acting on the control pressure supplied to the first port 503 and a second land acting on the control pressure supplied to the second port 505. 519, a third land 521 for selectively communicating the third port 507 and the fourth port 509, and optionally the fourth port 509 together with the third land 521. And the fourth land 523 for communicating the fifth port 511 or for communicating the fifth port 511 with the discharge port 515, and acting on the control pressure supplied to the sixth port 513. It consists of the fifth land 525.

Accordingly, the accumulator switch valve 501 is controlled by the valve spool being supplied to the second port 505 and the sixth port 513 at the forward travel range and the second, third, and L range shift stages. It is controlled and moved to the left in the drawing, and is supplied to the fourth clutch C4 from the second switch valve 120 at the forward 2, 3 speed, 2 range 2 speed, 3 range 2, 3 speed and L range. The operating pressure is connected to the accumulator 500 for the third clutch C3 through the fifth port 511 and the fourth port 509 to mitigate the impact of the operating pressure,

In the neutral (N), parking (P) and reverse (R) range shifting stage is controlled by the control pressure supplied to the first port 503 or the second port 505 to move to the right in the drawing, The operating pressure supplied from the NR control valve 126 to the third clutch C3 is operated by connecting the accumulator 500 for the third clutch C3 through the third port 507 and the fourth port 509. It will mitigate the impact of pressure.

In the hydraulic control system according to the present invention, the hydraulic pressure discharged from the oil pump 100 is adjusted to a constant hydraulic pressure by the regulator valve 102 in the neutral (N) range as shown in FIG. 3. After depressurizing through 108, the damper clutch control valve 106 and the first, second and third pressure control valves 110, 112, 114 are respectively supplied.

And the line pressure is the first, second, third pressure control valves 110, 112, 114, the second fail-safe valve 124 and the second switch through the manual valve 116 and the N range pressure pipeline 130 At the same time as the valve 120 is supplied to the first fail-safe valve 122.

At this time, the first solenoid valve S1 and the on / off solenoid valve S4 controlled by the transmission control unit are controlled to be off, and the second and third solenoid valves S2 and S3 are controlled to the on state. As shown in FIG. 3, the fourth clutch C4 and the first brake B1 are operated to achieve neutrality.

In the parking range P, as shown in FIG. 7, the position of the valve spool of the manual valve 116 is different from that of the neutral (N) range, but the hydraulic pressure is the same, and the fourth clutch C4 and the first clutch are made the same. The brake B1 is operated to maintain the parking state.

In addition, as described above, in the neutral (N) range and the parking (P) range, the second port of the accumulator switch valve 501 is connected to the line pressure through the manual valve 116 and the N range pressure line 130. 505) and the valve spool moves to the right in the drawing, and when it is reversed, the operating pressure supplied from the NR control valve 126 to the third clutch C3 is transferred to the third port 507 and the fourth port. 509 connects to the accumulator 500 for the third clutch C3 and waits in a state capable of alleviating the impact of the operating pressure.

At the forward 1 speed of the running D range, as shown in FIG. 8, the 1st solenoid valve S1 is on-controlled and the 3rd solenoid valve S3 is off-controlled in said neutral state.

Accordingly, the hydraulic pressure supplied to the first brake B1 is cut off, and the hydraulic pressure supplied to the third pressure control valve 114 passes through the second switch valve 120 under the control of the third solenoid valve S4. By supplying to the first clutch C1, the first and fourth clutches C1 and C4 are operated so that the first speed is shifted.

In the stop state at the first speed as described above, neutral control is performed. At this time, if vehicle speed = 0, foot brake = on, throttle = off state is detected, the transmission control unit maintains the neutral state as shown in FIG. In this case, controlling the first brake B1 to be activated may deactivate the first clutch C1, which is an input clutch, on a hill, so that the vehicle may be pushed back by its own weight when the foot brake is released for restart. In this case, the first brake B1 is operated and controlled, and in this case, the engine is maintained at no load, thereby contributing to fuel efficiency improvement.

If the opening rate of the throttle valve is increased while the vehicle speed is increased in the above-described one-speed control state, shifting is performed at two speeds. In this case, as shown in FIG. 9, the transmission control unit is turned on in the state of the first forward speed. The second solenoid valve S2 controlled in the state is controlled on, and the on / off solenoid valve S4 is controlled on.

Then, the control pressure supplied to the second switch valve 120 is cut off due to the on control of the on / off solenoid valve S4, so that a port change is made and the first clutch C1 waits at the second switch valve 120. The hydraulic pressure supplied to the D range pipe line 128 was supplied, and the control pressure of the third pressure control valve 114 is supplied to the fourth clutch C4 through the second switch valve 120.

In addition, the first and fourth clutches C1 and C4 are operated by allowing the control pressure of the second pressure control valve 112 to be supplied to the second brake B2 via the second fail-safe valve 124. As the second brake B2 is operated, the second speed is shifted.

If the opening speed of the throttle valve is increased while the vehicle speed is further increased in the two-speed control state as described above, the first solenoid valve S1 being controlled to the on state is turned off as in FIG. 10 at the third speed state. It controls and controls the 2nd solenoid valve S2 which was controlled to the off state to the on state.

Then, the hydraulic pressure supplied from the second pressure control valve 112 is cut off, so that the operation of the second brake B2 is released, and the hydraulic pressure by the first pressure control valve 110 is released through the first switch valve 118. The third speed is shifted while being supplied to the second clutch C2.

If the opening speed of the throttle valve increases while the vehicle speed is further increased in the three-speed control state as described above, the second solenoid valve S2 that is on-controlled is turned off as shown in FIG. 11 in the third speed state. The on-off control of the third solenoid valve S3 that has been controlled off is performed.

Then, while the hydraulic pressure supplied to the fourth clutch C4 is cut off by the on control of the third pressure control valve 114, the operation of the fourth clutch C4 is released, and the off control of the second solenoid valve S2 is thereby performed. The controlled hydraulic pressure is supplied to the second clutch C2 via the first switch valve 122, whereby the first and third clutches C1 and C3 and the second brake B2 are operated to perform four speed shifts. You lose.

In the L range 1 speed, unlike the forward 1 speed, as shown in FIG. 12, the first solenoid valve S1 is controlled to be off so that the hydraulic pressure from the second pressure control valve 112 is controlled by the first switch valve 118. And by supplying to the first brake (B1) through the first fail-safe valve 122, the shift is made by the operation of the first and fourth clutch (C1) (C4) and the first brake (B1).

On the other hand, in the traveling (D) range, the 1,2,3,4 speed and the L range as described above, the line pressure is passed through the accumulator switch valve (N, D range pressure line 130, 128 of the manual valve 116). 501) is supplied to the second port 505) and the sixth port 513 and the valve spool moves to the left in the drawing, in the forward 1 → 2, 4 → 3, power off 4 → 2 shift and manual shift, The operating pressure supplied from the second switch valve 120 to the fourth clutch C4 is connected to the accumulator 500 for the third clutch C3 through the fifth port 511 and the fourth port 509. It helps to alleviate the impact of the working pressure.

FIG. 13 is a flow chart of hydraulic pressure in the reverse R range, in which the second and third solenoid valves S2 and S3 and the on / off solenoid valve S4 except for the first solenoid valve S1 are turned off. .

Accordingly, the hydraulic pressure of the line pressure line 126 is supplied to the fourth clutch C4 via the second switch valve 120, and the NR control valve 126 is controlled by the on / off solenoid valve S4 off control. While the control is controlled, the hydraulic pressure supplied to the R range pressure line 134 is supplied to the third clutch C3 to perform the reverse shift.

In this reverse shifting process, the N → R input control is performed while the first brake B1 is operated in neutral to prevent rotation of the power train by dragging. Since the shift is performed in the caught state, the shock caused by the fastening of the first brake B1 disappears, thereby preventing the occurrence of the double shock.

As described above, the hydraulic control system of the present invention is an accumulator for controlling the accumulator in the valve body so that the accumulator that has been applied and used can be shared and used for two or more friction elements without changing the electronic control or the transmission case. By adding the control means, it is possible to minimize the shift shock during power-off or manual shifting, without the addition of an accumulator that has to change the layout of the entire transmission.

In addition, all friction elements controlled during shifting are independently controlled by the clutch-clutch control method, but an indirect control method is adopted in which the secondary control pressure is supplied to the friction element. As a result, shift response can be improved.

In addition, by applying a separate line pressure solenoid valve, the transmission control unit according to the operating conditions to control the solenoid valve to maintain the optimum hydraulic pressure, the neutral control is made in the stop state while driving, thereby improving fuel economy do.

As described above, the neutral control is performed in the stop state while driving to reduce the vibration, and the shift control for the input element in the state where the friction element acting as the reaction force element in the neutral state is operated during N → R, N → D manual shifting. Will be made, the invention that can minimize the shift shock.

Claims (25)

With the engine started, the hydraulic pressure generated from the oil pump is regulated to a constant pressure by the regulator valve, partly supplied to the working pressure of the damper clutch and the reducing valve, and the other part selectively to the friction elements operating at each shift stage. In order to supply the operating pressure is made to be supplied to the hydraulic control unit including the shift control means, pressure control means, switching means, fail safe means, NR control means, One side of the hydraulic control unit further comprises an accumulator control means to selectively connect two or more operating pressures for operating the friction element to one accumulator to be used in common, The shift control means is made of a manual valve in communication with a plurality of conduits to supply hydraulic pressure through each range conduit while being linked to the driver's select lever operation, The pressure control means may be independently controlled by first, second and third solenoid valves for controlling the control pressure supplied from the reducing valve, and respectively by the control pressures supplied from the first, second and third solenoid valves. It consists of the first, second, third pressure control valve for controlling the hydraulic pressure supplied from the valve, The switching means includes a friction between the first switch valve for selectively supplying the hydraulic pressure supplied from the first pressure control valve to two flow paths, the hydraulic pressure supplied from the third pressure control valve and the hydraulic pressure supplied from the manual valve. A second switch valve for supplying to the second switch valve for supplying to the urea, The fail-safe means includes a first fail safe valve for supplying the hydraulic pressure supplied from the first switch valve and the manual valve to a friction element operated at low speed and backward, and the second and fourth speeds for the hydraulic pressure supplied from the second pressure control valve. A second fail-safe valve for supplying to the friction element operating at The N-R control means is composed of an N-R control valve for controlling the reverse pressure to supply to the clutch operating only in the reverse shift stage, The accumulator control means is controlled by the hydraulic pressure supplied from the manual valve and is supplied to the corresponding clutch from the second switch valve in the forward 2, 3 speed, 2 range 2 speed, 3 range 2, 3 speed and L range. And an accumulator switch valve that selectively connects the accumulator to shock relief of the pressure and shock relief of the operating pressure supplied from the NR control valve to the clutch upon retraction. The method according to claim 1, wherein between the reducing valve and the regulator valve forming the decompression means An automatic transmission hydraulic control system for a vehicle, characterized by arranging a solenoid valve which is duty controlled by a transmission control unit. The method of claim 1, wherein the manual valve Line pressure line receiving line pressure from the regulator valve, N, D range line connected to the first pressure control valve and the second fail-safe valve in the N and D range, and the first switch valve and the second pressure in the D range. A control valve, a D range conduit connected to the third pressure control valve and a second switch valve, an L range pressure conduit connected to the first switch valve in the L range, a regulator valve and a second fail-safe valve in the R range, Automotive hydraulic transmission control system, characterized in that the "R" range pressure line is connected to the NR control valve. The method of claim 1, wherein the first, second, third solenoid valve An automatic transmission hydraulic control system for a vehicle, characterized by consisting of a three-way valve that maintains an open state in an off state. The method of claim 1, wherein the first pressure control valve A first port for receiving the reduced pressure from the reducing valve; A second port for receiving hydraulic pressure from the manual valve; A third port for supplying hydraulic pressure supplied to the second port to a first switching valve; A valve body including a fourth port for receiving a control pressure from the first solenoid valve; A first land having a hydraulic pressure supplied to the first port and having a small diameter; A second land to which the hydraulic pressure supplied to the first port operates and selectively opens and closes the second port; And a third land for selectively communicating with the second port and the third port together with the second land, wherein the ball spool is disposed between the third land and the valve body. Transmission hydraulic control system. The method of claim 1, wherein the second pressure control valve A first port for receiving the reduced pressure from the reducing valve; A second port for receiving hydraulic pressure from the manual valve; A third port for supplying hydraulic pressure supplied to the second port to a second fail safe valve; A valve body including a fourth port for receiving a control pressure from the second solenoid valve; A first land having a hydraulic pressure supplied to the first port and having a small diameter; A second land for selectively opening and closing a second port at the same time the hydraulic pressure supplied to the first port is operated; And a third land for selectively communicating with the second port and the third port together with the second land, and comprising a valve spool disposed between the third land and the valve body. Automatic transmission hydraulic control system for vehicles. The method of claim 1, wherein the third pressure control valve A first port for receiving the reduced pressure from the reducing valve; A second port for receiving hydraulic pressure from the manual valve; A third port for supplying hydraulic pressure supplied to the second port to a second switch valve; A valve spool including a fourth port for receiving a control pressure from the third solenoid valve; A first land having a hydraulic pressure supplied to the first port and having a small diameter; A second land for selectively opening and closing the second port while acting on the hydraulic pressure supplied to the first port; And a third land for selectively communicating with the second port and the third port together with the second land, wherein a valve spool is disposed between the third land and the valve body. An automatic transmission hydraulic control system for a vehicle. The method of claim 1, wherein the first switch valve And the N and D range pressures supplied from the first pressure control valve are selectively supplied to the first brake through the second clutch and the first fail safe valve. The method of claim 1, wherein the first switch valve A first port for supplying the N and D range pressures to the control pressure from the manual valve, a second port for supplying the L range pressure to the control pressure from the manual valve, and a third port for supplying the control pressure from the on / off solenoid valve And a fourth port for receiving hydraulic pressure from the first pressure control valve, a fifth port for supplying control pressure of the second clutch and the first and second fail-safe valves to supply the hydraulic pressure supplied to the fourth port. A valve body including a sixth port for supplying hydraulic pressure supplied to four ports to the first fail safe valve, and first and second discharge ports for discharging the hydraulic pressure returned to the fifth and sixth ports; A first land acting on the control pressure supplied to the first port, a second land for selectively communicating the fourth port and a sixth port, and a third for selectively communicating the fourth port and the fifth port A valve automatic spool comprising a land, a fourth land acting on the control pressure supplied to the third port, and a fifth land on which the control pressure supplied to the second port operates. Control system. The method of claim 1 or 9, wherein the first switch valve In the forward 1,2,3,4 shift stages, the operating pressure supplied from the first pressure control valve at the 3rd and 4th speeds is supplied to the second clutch while being controlled by the control pressure supplied to the first port. The hydraulic pressure is supplied to the second clutch and the first brake at the same time by converting the flow path so that the operating pressure supplied from the first pressure control valve can be supplied to the first brake while being controlled by the control pressure supplied from the second port and the third port. Automatic transmission hydraulic control system for a vehicle, characterized in that it prevents. The method of claim 1, wherein the second switch valve In the forward 2, 3 and 4 speeds, the hydraulic pressure supplied from the third pressure control valve is supplied to the fourth clutch, and the D range pressure supplied from the manual valve is supplied to the first clutch, and on / off in the N, P, and R ranges. The line pressure is supplied to the fourth clutch while being controlled by the solenoid valve, and the D-range pressure supplied from the manual valve while being controlled by the on / off solenoid valve is supplied to the fourth clutch in the L range, and is simultaneously supplied from the first pressure control valve. An automatic transmission hydraulic control system for a vehicle, characterized in that to supply the supplied hydraulic pressure to the first clutch. The method of claim 1, wherein the second switch valve A first port supplied with a D range pressure from a manual valve, a second port supplied with a control pressure from an on / off solenoid valve, a third port supplied with hydraulic pressure from a third pressure control valve, and a line pressure supplied A fourth port, a fifth port for supplying the hydraulic pressure supplied to the third port to the first clutch, a sixth port for supplying the hydraulic pressure supplied to the first port to the first clutch, and the fourth port The seventh port for supplying the supplied hydraulic pressure to the fourth clutch, the eighth port for supplying the hydraulic pressure supplied to the third port to the fourth clutch, and the hydraulic pressure returned to the fifth, six, seven, and eight ports. A valve body including first and second discharge ports for discharging; First and second lands that selectively block and communicate with the first port and the sixth port while acting on the control pressure supplied to the first port, and third lands that selectively communicate with and block the third and fifth ports And a fourth land for selectively communicating and blocking the third and eighth ports, a fifth land for selectively communicating and blocking the fourth and seventh ports, and a control supplied to the second port. An automatic transmission hydraulic control system for a vehicle, comprising a valve spool including a sixth land acting on pressure. The conduit of claim 12, wherein the conduits respectively connected to the fifth and sixth ports of the second switch valve The first clutch communicates with the first clutch through a first shuttle valve, and a pipe line is branched on the downstream side of the first shuttle valve to intersect the pipe branch branched from an upstream side of the first port and a first valve to suppress hydraulic flow. Automatic transmission hydraulic control system for a vehicle, characterized in that the communication. The conduit according to claim 13, wherein the conduit branched from the first port upstream of the second switch valve A hydraulic control system for an automatic transmission for a vehicle, characterized in that connected to the operating pressure of the first and second fail-safe valves and the first brake through a second check valve that branches back to control the hydraulic flow downstream. The method of claim 12, wherein the second switch valve The pipelines connected to the seventh and eighth ports, respectively, communicate with the fourth clutch through the second shuttle valve, and in the downstream side of the second shuttle valve, the pipeline branches and supplies the control pressure of the second fail-safe valve. Automatic transmission hydraulic control system for a vehicle, characterized in that configured to. The method of claim 1, wherein the first fail safe valve is The hydraulic pressure supplied to the first switch valve is controlled by the line pressure in the N, P, L range and supplied to the first brake, and the hydraulic pressure supplied from the R range pressure pipeline in the R range is supplied to the first brake. Automotive transmission hydraulic control system. The method of claim 1, wherein the first fail safe valve is A first port supplied with the hydraulic pressure supplied to the second clutch at the control pressure, a second port supplied with the hydraulic pressure supplied to the second brake at the control pressure, a third port supplied with the line pressure at the control pressure, and R A valve body including a fourth port supplied through the third shuttle valve to the hydraulic pressure supplied from the range pressure line and the first switch valve, and a fifth port supplying the hydraulic pressure supplied to the fourth port to the third clutch; ; A first land acting on the control pressure supplied to the first port, a second land acting on the control pressure supplied to the second port, and a third land selectively communicating the fourth and fifth ports And a fourth land for selectively communicating the fourth port with the fifth port together with the third land, and a valve spool including a fifth land acting by a control pressure supplied to the third port. Automatic transmission hydraulic control system for vehicles. The method of claim 1, wherein the second fail safe valve is A hydraulic control system for a vehicle automatic transmission, characterized in that configured to supply the hydraulic pressure supplied from the second pressure control valve at the second and fourth speed forward to the second brake. The method of claim 1, wherein the second fail safe valve is A first port through which the R range pressure is supplied as the control pressure, a second port through which a part of the hydraulic pressure supplied to the fourth clutch is supplied as the control pressure, and a part in which a part of the hydraulic pressure supplied to the second clutch is supplied as the control pressure A third port, a fourth port for supplying the N range pressure as the control pressure, a fifth port for receiving the hydraulic pressure from the second pressure control valve, and a sixth for supplying the hydraulic pressure supplied to the fifth port to the second brake; A valve spool comprising a port; A first land to which the control pressure supplied to the first port acts, a second land to which the control pressure supplied to the second port acts, and a third land to which the control pressure supplied to the third port acts; And a fourth land for selectively communicating the fifth and sixth ports, a fifth land for communicating the fifth and sixth ports together with the fourth land, and a control pressure supplied to the fourth port. The automatic transmission hydraulic control system for a vehicle, characterized in that consisting of a valve spool including a sixth land acting. The N-R control valve of claim 1, wherein And a hydraulic pressure supplied from a manual valve to the third clutch while being controlled by the control pressure supplied from the second solenoid valve in the R range. The N-R control valve of claim 1, wherein A valve body comprising a first port to receive the control pressure of the second solenoid valve, a second port connected to the R range pressure line, and a third port to supply hydraulic pressure supplied to the second port to the third clutch. Wow; A first land on which hydraulic pressure flowing into the first port acts; And a second land for selectively opening and closing the second and third ports, wherein the automatic transmission hydraulic control system for the vehicle comprises a valve spool in which an elastic member is supported between the second land and the valve body. The method of claim 21, wherein the third port of the N-R control valve The automatic transmission hydraulic control system for a vehicle, characterized in that the downstream side is branched and connected to the R range pressure pipeline through a third check valve that suppresses flow to the downstream side. The accumulator switch valve of claim 1, wherein Prior to supplying the R range pressure supplied from the NR control valve and the D range pressure supplied through the third pressure control valve and the second switch valve to the fourth and third clutches, the operating pressure is selectively connected to one accumulator. Automatic transmission hydraulic control system for a vehicle, characterized in that to mitigate the impact of. The accumulator switch valve of claim 1, wherein A first port supplied with the R range pressure as a control pressure from the manual valve, a second port supplied with the N range pressure as the control pressure from the manual valve, a third port supplied with hydraulic pressure from the NR control valve, and the fourth port A fourth port for connecting the hydraulic pressure supplied to the port to the accumulator, a fifth port for receiving hydraulic pressure from the second switch valve, a sixth port for supplying the D range pressure as a control pressure from the manual valve, and the fifth port A valve body including a discharge port for discharging hydraulic pressure returned from the port; A first land acting on the control pressure supplied to the first port, a second land acting on the control pressure supplied to the second port, and a third land selectively communicating the third port and the fourth port And a fourth land for selectively communicating with the fourth port and the fifth port together with the third land, or a fourth land for communicating the fifth port with the discharge port, and acting on a control pressure supplied to the sixth port. The automatic transmission hydraulic control system for a vehicle, characterized in that consisting of a valve spool including a fifth land. The accumulator switch valve of claim 1, wherein the accumulator switch valve In the forward travel range and the 2, 3 and L range gears, it is controlled by the control pressures supplied to the second and sixth ports, and the forward 2, 3 speed, 2 range 2 speed, 3 range 2, 3 speed and At the L range, the operating pressure supplied from the second switch valve to the fourth clutch is connected to the accumulator through the fifth and fourth ports to mitigate the impact of the operating pressure, and at the neutral, parking and reverse range shift stages, While controlled by the control pressure supplied to the first and second ports, the operating pressure supplied from the NR control valve to the third clutch when reversing is connected to the accumulator through the third and fourth ports to mitigate the impact of the operating pressure. Automatic transmission hydraulic control system for a vehicle, characterized in that made to.