KR20040040233A - Hydraulic control system of automatic transmission for vehicle - Google Patents

Abstract

PURPOSE: A hydraulic control system of an automatic transmission for a vehicle is provided to improve shift quality by obtaining uniform hydraulic pressure in a duty region regardless of a change of line pressure and to prevent lowering of the shift quality caused by quality variation. CONSTITUTION: In a hydraulic control system of an automatic transmission for a vehicle, hydraulic pressure generated from an oil pump(2) is controlled in a regulator valve(4) by uniform pressure and is supplied to a pressure control part(A) and a passage switch part(B). The pressure control part comprises a manual valve(6), first, second, third, fourth, and fifth solenoid valves(S1,S2,S3,S4,S5) and first, second, third, fourth, and fifth pressure control valves(10,12,14,16,18). The passage switch part selectively switches passages and supplies the hydraulic pressure, supplied from the first and second pressure control valves and the fifth pressure control valve, to friction elements. The first and fifth solenoid valves receive line pressure by control pressure. The second, third, and fourth solenoid valves receive the pressure of a reducing valve(8) by control pressure.

Description

HYDRAULIC CONTROL SYSTEM OF AUTOMATIC TRANSMISSION FOR VEHICLE}

The present invention relates to a hydraulic control system for an automatic transmission for a vehicle, and more particularly, by supplying a control pressure supplied to a plurality of solenoid valves applied to a hydraulic control unit as a reducing pressure, regardless of a change in line pressure in a duty section. The present invention relates to a hydraulic control system of an automatic transmission in which it is possible to obtain a constant hydraulic pressure, thereby improving the transmission feeling and preventing a reduction in the transmission feeling caused by quality deviation.

For example, an automatic transmission applied to a vehicle is controlled by a shift control device controlling a plurality of solenoid valves to control hydraulic pressure according to a traveling speed of a vehicle, an opening ratio of a throttle valve, and various detection conditions, thereby operating a gear shift of a target shift stage. To make the shift.

In other words, when the driver converts the select lever to the desired shift stage, the manual control port is changed in the hydraulic control system, and the hydraulic pressure supplied from the oil pump is selectively selected according to the duty control of the solenoid valve. To make the shifting work.

Among these automatic transmissions, an automatic transmission having shift speeds of five forward and one reverse speeds is recently mounted. The automatic five-speed automatic transmission has a reverse clutch (R / C) that operates only in reverse, as shown in FIG. Low-reverse brake (LR / B) operating in reverse and forward 1 speed, second brake (2ND / B) operating in forward 2, 4 and 5, and underdrive clutch operating in forward 1,2,3 UD / C), overdrive clutch (OD / C) operating at forward 3, 4, 5 speed, reduction brake (RD / B) operating at forward 1, 2, 3, 4 and reverse, 5 forward It has seven friction elements, such as a working direct clutch (D / C).

In addition, the friction elements are shifted by basically operating and controlling two at each shift stage. It is very difficult to control two friction elements at the same time, and in the past, the one-way clutch has not been developed. Asynchronous shift was performed.

That is, instead of controlling two friction elements at once, one element is controlled by a one-way clutch and only one element is controlled by electronic control. In the tip off of the accelerator pedal, there is a problem that requires the additional installation of the friction element for the engine brake operation as a means for mitigating the risk due to the non-operation of the engine brake due to free wheeling.

Recently, however, advances in electronic control technology have enabled precise control of two friction elements, and thus a clutch-to-clutch control method for simultaneously controlling two friction elements independently has been applied.

In view of the above, a configuration of a conventional hydraulic control system for operating the friction element is described. As shown in FIG. 2, the hydraulic pressure generated by the oil pump 202 is controlled at a constant pressure in the regulator valve 204, and thus the manual. Sent to valve 206.

Then, the manual valve 206 converts the flow path according to the range selection of the select lever, not shown, to the first, second, third, fourth, and fifth solenoid valves S1, S2, S3, S4, and S5 that control hydraulic pressure. Supplied via switch valves 218 or first and second fail-safe valves through first, second, third, fourth and fifth pressure control valves 208, 210, 212, 214 and 216 according to their control. The connection is configured to be supplied via the 220 or 222 directly to the friction element so that the shift is made while operating each friction element as described above at each shift stage.

That is, the first solenoid valve S1 and the first pressure control valve 208 are connected to the low-reverse brake LR / B via the switch valve 218 and the first fail safe valve 220. The two solenoid valve S2 and the second pressure control valve 210 are connected to the second brake 2ND / B via the second fail safe valve 222.

The third solenoid valve S3 and the third pressure control valve 212 are directly connected to the underdrive clutch UD / C, and the fourth solenoid valve S4 and the fourth pressure control valve 214 are overdriven. Directly connected to the clutch (OD / C), the fifth solenoid valve (S5) and the fifth pressure control valve 216 is directly connected to the reduction brake (RD / B) and at the same time through the third fail-safe valve (224). It has a configuration connected to the direct clutch (D / C).

In addition, a part of the hydraulic pressure controlled from the regulator valve 204 is a torque converter control valve 226 which is constantly adjusted for the torque converter TC and lubrication, and a damper clutch to increase the power transmission efficiency of the torque converter TC. Is supplied to the damper clutch control valve 228 to control, the damper clutch control valve 228 is configured to control the on / off operation of the damper clutch while being controlled by the sixth solenoid valve (S6).

By such a configuration, the first, second, third, fourth, fifth, and sixth solenoid valves are driven under the control of the transmission (TCU), and the hydraulic pressure is supplied / released to the friction element at each shift stage so that the shift is performed. Will be.

In the hydraulic control system as described above, the control pressure supplied to the first, second, third, fourth and fifth solenoid valves is directly supplied from the regulator valve or is supplied through the manual valve. Will be used.

However, the line pressure in the hydraulic control system varies greatly depending on the driving conditions of the vehicle. When using the fluctuating line pressure, the solenoid valve acts sensitively to supply the operating pressure supplied to each friction element. As a result, there is a problem that a high quality shifting feeling cannot be obtained.

In addition, there is a problem that it is not possible to prevent the reduction of the shift feeling due to the quality deviation between the automatic transmission.

Therefore, the present invention has been invented to solve the above problems, the object of the present invention is to reduce the pressure of the solenoid valve control pressure of the plurality of solenoid valve in the traveling section from the 1st speed to the 5th speed forward with reducing pressure By supplying, a hydraulic pressure control system of an automatic transmission for a vehicle is provided so that a constant hydraulic pressure can be obtained in a duty section irrespective of a change in line pressure, thereby improving the transmission feeling and preventing a reduction in the transmission feeling caused by the quality variation of the transmission period.

1 is a hydraulic flow chart in the N, P range of the hydraulic control system according to the present invention.

Figure 2 is a flow chart of the hydraulic pressure in the N, P range of the conventional hydraulic control system.

In order to realize this, the present invention, the hydraulic pressure generated in the oil pump is controlled to a constant pressure in the regulator valve, the manual valve, the first, second, third, fourth, fifth solenoid valve and the first, second, third, fourth, fifth A pressure control unit comprising a pressure control valve, and a hydraulic pressure supplied from the first and second pressure control valves and a fifth pressure control valve to be selectively supplied to a flow path switching unit for supplying hydraulic pressure to a friction element connected to the flow path. In the hydraulic control system of the automatic transmission for a vehicle,

The first and fifth solenoid valves are configured to receive line pressure as the control pressure, and the second, third and fourth solenoid valves are configured to receive the pressure of the reducing valve controlled to reduce the line pressure to a lower and more stable pressure. It provides a hydraulic control system of an automatic transmission for a vehicle.

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 hydraulic flow chart in the N, P range of the hydraulic control system according to the present invention, the hydraulic pressure generated in the oil pump (2) is controlled to a constant pressure in the regulator valve (4) to reduce with the manual valve (6) The valve 8 is supplied to the hydraulic control unit A and the like.

In the manual valve (6), the flow path is converted according to the range selection of the select lever (not shown), and in the reducing valve (8), the pressure is reduced and supplied to the hydraulic control unit (A), which is controlled by the hydraulic control unit (A). The supplied hydraulic pressure is supplied to the flow path switching portion B or the direct friction element.

The hydraulic control unit A is the first, second, third, fourth, fifth solenoid valves S1, S2, S3, S4, S5 and the first, second, respectively controlled by these solenoid valves. 3, 4, 5 pressure control valves 10, 12, 14, 16 and 18.

The flow path switching unit (B) comprises a switch valve 20 and first, second and third fail-safe valves 22, 24 and 26, and the manual valve 6 and the reducing valve 8 ), And the connection relationship between the hydraulic control unit (A) and the flow path switching unit (B) in detail as follows.

In the manual valve 6, the D range pressure line 28, the N range pressure line 30, and the R range pressure line 32 communicate with each other to supply the hydraulic pressure of the line pressure line 34 in accordance with the range change. do.

The D range pressure line 28 is in communication with the second, third and fourth pressure control valves 14, 16, 18, and the N range pressure line 30 is a regulator valve 6 and a first fail-safe valve. Communicating so that the hydraulic pressure can be supplied to the control pressure of 22, the R range pressure pipeline 32 is the operating pressure of the reverse clutch (R / C) operating in the reverse (R) range and the second fail-safe valve (24) It is in communication so that it can be supplied at the control pressure.

The reducing valve 8 controls the line pressure to a lower stable pressure and communicates with the second, third and fourth solenoid valves S2, S3, and S4 so as to supply a control pressure.

Line pressure is supplied to the first and fifth solenoid valves S1 and S5 as a control pressure, and line pressure is also supplied to the first and fifth pressure control valves 10 and 18 so that the first and fifth solenoid valves ( S1 is controlled by S5 and supplied to the switch valve 20 at the second control pressure or directly to the reduction brake R / B.

The first solenoid valve S1 and the first pressure control valve 10 of the hydraulic control unit A are provided with a low-reverse brake (LR / B) via a switch valve 20 and a first fail-safe valve 22. Is connected to the direct clutch D / C via the third fail-safe valve 26, and the second solenoid valve S2 and the second pressure control valve 12 are connected to the second fail-safe valve 24. ) Is connected to the second brake (2ND / B).

The third solenoid valve S3 and the third pressure control valve 14 are directly connected to the underdrive clutch UD / C, and the fourth solenoid valve S4 and the fourth pressure control valve 16 are overdriven. The clutch OD / C is directly connected, and the fifth solenoid valve S5 and the fifth pressure control valve 18 are directly connected to the reduction brake RD / B.

By the above configuration, the reverse clutch R / C operates in reverse, the low-reverse brake LR / B operates in reverse and forward 1 speed, and the second brake 2ND / B moves forward 2, 4, 5 Inside, underdrive clutch (UD / C) operates forward 1, 2, 3, overdrive clutch (OD / C) operates forward 3, 4, 5, reduction brake (R / B) operates at forward 1, 2, 3, 4 and reverse, and the direct clutch (D / C) is shifted while operating pressure is supplied at 5 forward.

In addition, part of the hydraulic pressure controlled from the regulator valve 6 is the torque converter TC, which is the damper clutch control unit C, and the torque converter control valve 36 which is constantly adjusted for lubrication, and the power of the torque converter TC. The damper clutch control valve 38 is supplied to a damper clutch control valve 38 for controlling the damper clutch in order to increase the transmission efficiency, and the damper clutch control valve 38 is controlled by the sixth solenoid valve S6 to perform the on / off operation of the damper clutch. It is configured to be controlled.

And the regulator valve 6 is controlled by the seventh solenoid valve (S7) to control the line pressure to match the vehicle driving conditions.

Since each shift stage hydraulic flow of the hydraulic control system as described above is the same as in the prior art, a detailed description thereof will be omitted. In the present invention, by additionally arranging the reducing valve 8 in the existing hydraulic system, the duty control may be performed at the forward shift stage. The second, third, and fourth solenoid valves S2, S3, and S4 may be operated by a stable control pressure.

Accordingly, the second, third and fourth pressure control valves 12, 14 and 16 controlled by the second, third and fourth solenoid valves S2, S3 and S4 are stably operated, and the second brake ( 2ND / B), underdrive clutch (UD / C), and overdrive clutch (O / C) are supplied with stable operation to greatly improve the feeling of shifting.

As described above, according to the present invention, by supplying a plurality of solenoid valve control pressures that frequently perform the control operation in the running range from the 1st forward speed to the 5th speed as the reducing pressure, the duty interval regardless of the fluctuation of the line pressure In order to obtain a constant hydraulic pressure in the improved transmission, it is an invention to prevent the reduction of the shift by the quality deviation of the shift period.

Claims (1)

The hydraulic pressure generated from the oil pump is controlled to a constant pressure in the regulator valve so that the pressure control unit includes a manual valve, first, second, third, fourth and fifth solenoid valves, and first, second, third, fourth and fifth pressure control valves. Hydraulic pressure control system of the automatic transmission for a vehicle is configured to be supplied to the flow path switching unit for supplying the hydraulic pressure to the friction element connected to the flow path selectively connected to the hydraulic pressure supplied from the first and second pressure control valve and the fifth pressure control valve To The first and fifth solenoid valves are supplied with a line pressure as a control pressure, and the second, third and fourth solenoid valves are configured to receive a pressure of a reducing valve controlled at a reduced pressure in a lower and stable line pressure as a control pressure. Hydraulic control system of an automatic transmission for a vehicle, characterized in that.