KR100394679B1 - Hydraulic control system of continuously variable transmission for vehicle - Google Patents

Abstract

The oil pressure is stored between the primary pulley and the secondary pulley so that the oil pump can be supplied by supplying the stored oil pressure to the pulley side as needed, so that a smaller oil pump can be applied. To provide a hydraulic control system of a continuously variable transmission for a vehicle that can improve and light weight, and reduce production costs;

In a continuously variable transmission for a vehicle such that the speed change is performed in accordance with the diameter displacement of the primary pulley and the secondary pulley mounted on the input shaft and the output shaft,

A solenoid is installed between the primary pulley and the secondary pulley to install a reservoir capable of storing oil, optionally allowing the hydraulic pressure of the secondary pulley to be stored in the reservoir, and to control the supply of the stored oil to the primary pulley. Provided is a hydraulic control system for a continuously variable transmission for a vehicle formed by arranging a valve.

Description

HYDRAULIC CONTROL SYSTEM OF CONTINUOUSLY VARIABLE TRANSMISSION FOR VEHICLE}

The present invention relates to a hydraulic control system for a continuously variable transmission for a vehicle, and more particularly, an oil pump having a predetermined pressure or more stored between a primary pulley and a secondary pulley so that the stored hydraulic pressure can be supplied to the pulley side as needed. By assisting the present invention, the hydraulic control system of a continuously variable transmission for a vehicle that can improve the fuel economy by enabling the application of a smaller capacity oil pump.

For example, the transmission of the vehicle has a function of transmitting the rotational force of the engine to the drive wheels, and such a transmission includes a manual transmission in which the driver directly selects a shift stage at the driver's will, and automatic transmission in which the shift is automatically performed according to the driving conditions of the vehicle. It is roughly classified into a transmission and a continuously variable transmission in which continuously shifting is performed without a specific shift range between each shift stage.

In the transmission as described above, the present invention relates to a continuously variable transmission having a great advantage in terms of fuel economy, power transmission performance, and weight by complementing the disadvantages of the automatic transmission using hydraulic pressure, the continuously variable transmission thereof is mounted on the input shaft and the output shaft The method using the diameter displacement of a pulley is mainly used.

In such a continuously variable transmission, the driving and driven shaft pulleys consist of the fixed side pulley and the moving side pulley, and the variable side pulley is provided on the side of the metal belt at a level suitable for the driving torque by the hydraulic pressure acting on the hydraulic chamber formed on the rear side of the variable side pulley. Thrust is applied, and the speed change is made according to the diameter change of these pulleys.

Looking at the configuration of the hydraulic system for controlling the hydraulic pressure used as a power source for the variable diameter of the belt pulley, as shown in Figure 3, the hydraulic pressure pumped from the oil pump 202 through the primary line pressure control valve 204 The line pressure is primarily adjusted and supplied to the secondary line pressure control valve 206 and the secondary pulley 208 of the continuously variable transmission.

In the secondary line pressure regulating valve 206, the hydraulic pressure firstly adjusted is secondarily adjusted again to provide a solenoid supply valve 210, a reducing valve 212 as a pressure reducing means, and a damper clutch control valve of a damper clutch control means. 214 is supplied to the pressure control valve 216 of the forward and backward control means.

The hydraulic pressure supplied to the solenoid supply valve 210 is supplied to the first and second solenoid valves S1 and S2 under a reduced pressure, and the primary line pressure control valve is controlled by the first solenoid valve S1. Reference numeral 24 controls the speed ratio control valve 218 under the control of the second solenoid valve S2 to control the hydraulic pressure supplied to the primary pulley 220 of the continuously variable transmission mechanism.

The hydraulic pressure reduced by the reducing valve 212 is supplied to the third solenoid valve S3 of the forward and reverse control means and the fourth solenoid valve S4 of the damper clutch control means, and the third solenoid valve S3. The hydraulic pressure supplied to) controls the pressure control valve 216 according to the control of the third solenoid valve S3 to control the forward and backward pressure supplied to the manual valve 222, and to the fourth solenoid valve S4. The hydraulic pressure supplied controls the damper clutch control valve 214 and the safety valve 224 as safety means according to the control of the fourth solenoid valve S4.

In the above description, the first and second solenoid valves S1 and S2 are three-way valves, and the third and fourth solenoid valves S3 and S4 are on / off valves.

In addition, the damper clutch control valve 214 supplies hydraulic pressure supplied from the secondary line pressure regulating valve 206 and the torque converter feed valve 215 to the operating pressure of the damper clutch under the control of the fourth solenoid valve S4. By controlling the operation and non-operation of the damper clutch.

In addition, the hydraulic pressure supplied to the pressure control valve 216 is supplied to the manual valve 222 of the forward and backward control means while being controlled according to the control of the third solenoid valve S3, the manual valve 222 The forward and backward pressure pipelines 226 and 228 are connected, so that the hydraulic pressure of the forward pressure pipeline 226 is supplied to the fastening pressure of the forward friction member C while the accumulator 230 is interposed, and is safe. It is supplied at the control pressure of the valve 224.

And, the hydraulic pressure of the reverse pressure pipeline 228 is supplied to the fastening pressure of the friction member (B) for the reverse through the safety valve 224, the orifice in parallel on the front, reverse pressure pipelines (224, 226), respectively. (232) 234 and check valves 236 and 238 are arranged to be controlled by orifices 232 and 234 at the time of supply of the clamping pressure to the friction members C and B, and to release the check valve 236. 238 has a configuration that is quickly discharged.

However, in the hydraulic control system of the continuously variable transmission as described above, the shift is made while varying the diameter of the pulley. Since the high pressure is used as compared to the general automatic transmission, the loss in the oil pump is relatively dir 30 of the total continuously variable transmission loss. It is known to occupy ~ 40%.

As such, the greater the power loss occupied by the oil pump, the more advantageous it is to reduce the pump capacity. However, it may be difficult to reduce the capacity of the oil pump because a large flow rate may be required depending on the operating conditions.

In other words, although it is required to be somewhat lower in normal driving conditions, a large capacity oil pump must be used for kickdown and emergency brake situations that require large flow rates. In other words, the configuration is complicated.

Therefore, the present invention has been invented to solve the above problems, an object of the present invention is to store the hydraulic pressure above a certain pressure between the primary pulley and the secondary pulley to supply the stored hydraulic pressure to the pulley side as needed By assisting the oil pump, it is possible to apply a smaller capacity oil pump to improve the fuel economy and weight, and to provide a hydraulic control system of a continuously variable transmission for a vehicle that can reduce the production cost.

1 is a hydraulic flow chart in a neutral (N) range in the hydraulic control system according to the present invention.

Figure 2 is an enlarged schematic view showing the main part of the present invention.

Figure 3 is an embodiment of a conventional continuously variable transmission hydraulic control system.

In order to realize this, the present invention, in the continuously variable transmission for a vehicle such that the stepless shift is made according to the diameter displacement of the primary pulley and the secondary pulley mounted on the input shaft and the output shaft,

A solenoid is installed between the primary pulley and the secondary pulley to install a reservoir capable of storing oil, optionally allowing the hydraulic pressure of the secondary pulley to be stored in the reservoir, and to control the supply of the stored oil to the primary pulley. Provided is a hydraulic control system for a continuously variable transmission for a vehicle formed by arranging a valve.

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 hydraulic control system according to the present invention, the hydraulic control system for operating the belt-type continuously variable transmission, the hydraulic pressure pumped from the oil pump (2) is the line through the primary line pressure control valve (4) Pressure is primarily regulated and supplied to the secondary line pressure regulating valve 6 and the secondary pulley 8 of the continuously variable transmission.

In the secondary line pressure regulating valve 6, the primary hydraulic pressure is adjusted again to the second, so that the solenoid supply valve 10, the reducing valve 12, which is a pressure reducing means, and a damper clutch control valve of the damper clutch control means. At the same time, it is supplied to the pressure control valve 16 of the forward and backward control means.

The hydraulic pressure supplied to the solenoid supply valve 10 is supplied to the first and second solenoid valves S1 and S2 under a reduced pressure, and the primary line pressure control valve is controlled by the first solenoid valve S1. (4) is controlled, and the transmission ratio control valve 18 is controlled according to the control of the second solenoid valve S2 to control the hydraulic pressure supplied to the primary pulley 20 of the continuously variable transmission mechanism.

The hydraulic pressure reduced by the reducing valve 12 is supplied to the third solenoid valve S3 of the forward and backward control means and the fourth solenoid valve S4 of the damper clutch control means, and the third solenoid valve S3. The hydraulic pressure supplied to) controls the pressure control valve 16 according to the control of the third solenoid valve S3 to control the forward and backward pressure supplied to the manual valve 22, and to the fourth solenoid valve S4. The supplied hydraulic pressure controls the damper clutch control valve 14 and the safety valve 24 serving as safety means under the control of the fourth solenoid valve S4.

In the above description, the first and second solenoid valves S1 and S2 are three-way valves, and the third and fourth solenoid valves S3 and S4 are on / off valves.

The damper clutch control valve 14 supplies hydraulic pressure supplied from the secondary line pressure regulating valve 6 and the torque converter feed valve 15 to the operating pressure of the damper clutch under the control of the fourth solenoid valve S4. By controlling the operation and non-operation of the damper clutch.

In addition, the hydraulic pressure supplied to the pressure control valve 16 is supplied to the manual valve 22 of the forward and reverse control means while being controlled according to the control of the third solenoid valve S3, and to the manual valve 22 thereof. The forward and backward pressure pipelines 26 and 28 are connected so that the hydraulic pressure of the forward pressure pipeline 26 is supplied at the clamping pressure of the forward friction member C while the accumulator 30 is interposed, and is safe. It is supplied at the control pressure of the valve 24.

The hydraulic pressure of the reverse pressure pipeline 28 is supplied to the fastening pressure of the friction member B for reversing through the safety valve 24, and the orifices are arranged in parallel on the front and reverse pressure pipelines 24 and 26, respectively. (32) 34 and check valves 36 and 38 are arranged and controlled by orifices 32 and 34 at the time of supply of the clamping pressure to the friction members C and B, and upon release the check valve 36 (38) is to be discharged quickly.

Accordingly, in the neutral range, as shown in FIG. 1, the forward and backward pressures are cut off from the manual valve 22, so that no hydraulic pressure is supplied to any of the friction members C and B, and the forward pressure line 26 in the forward range. As the hydraulic pressure is supplied to the friction element C for moving forward through, a portion of the forward pressure is supplied to the left end of the safety valve 24 in the drawing to maintain the state in which the valve spool 40 is moved to the right.

In the reverse range, the manual valve 22 supplies the hydraulic pressure supplied from the pressure control valve 16 through the reverse pressure pipeline 26. In this case, the reducing valve is controlled by the off control of the fourth solenoid valve S4. As the control pressure of (12) acts on the right side of the safety valve 24, the valve spool 40 moves to the left to open the flow path so that the fastening pressure is supplied to the reverse friction member B so that the reverse shift is made. Will be.

In the hydraulic control system of the continuously variable transmission, the present invention installs a reservoir 50 capable of storing oil between the primary pulley 20 and the secondary pulley 8, and enters the reservoir 50 therein. A solenoid valve (SOL) to control the oil was placed.

The reservoir 50 has a built-in form of the spring 52 and the piston 54 to apply a predetermined pressure to the oil flowing thereto, the solenoid valve (SOL) is made of a three-way valve as shown in FIG. A first port 62 for closing the conduit 56 communicating with the primary pulley 20 and the conduit 60 communicating with the secondary pulley 8, and a conduit of the primary pulley 20 And a second port 64 connecting the reservoir 50 to the reservoir 50 and a third port 66 connecting the conduit 60 of the secondary pulley 8 to the reverser 50. Is done.

Accordingly, a part of the flow rate supplied to the secondary pulley 8 is introduced into the reservoir 50 through the pipe line 60 and the solenoid valve SOL to maintain a predetermined pressure or more, and if necessary, the primary pulley ( It is possible to supply hydraulic pressure to 20).

For this operation, once the oil must be stored in the reservoir 50, the storage conditions must be set. Since the hydraulic pressure of the secondary pulley required during the kick-down is about 20 bar, the storage hydraulic pressure is about 25 to 30 bar.

In addition, if it is necessary to fill the reservoir 50 with oil in a situation such as when the flow rate is not appropriate, the secondary pulley 8 is briefly increased in oil pressure and the solenoid valve S0L is connected to the third port 66. ) Is controlled so that the oil is stored in the reservoir 50, the solenoid valve SOL is controlled by the second port 64, and the hydraulic pressure is lowered to the normal hydraulic pressure.

After the oil is stored, it is maintained in preparation for kick-down or sudden stop while continuing to be maintained until the start is turned off.The fluid thus stored requires a large flow rate to the primary pulley 20 in addition to the kick-down or sudden stop. In the manual mode, the fluid is supplied to the primary pulley 20 so that the system can be operated without problems even with a small oil pump.

Specifically, a small capacity oil pump is sufficient under normal driving conditions in a continuously variable transmission, but a large amount of oil pump is required because a large amount of oil is required at a rapid shift such as a kickdown.

However, large capacity oil pumps have a lot of losses and worsen the efficiency. Therefore, by installing a special pump (2 stages) and controlling the stage using a separate solenoid valve, etc., only one stage is used to increase efficiency during normal driving. Efforts have been made to increase the efficiency, but in this case, since the cost is greatly increased, it is possible to increase the efficiency at a small cost by using the method of the present invention.

As described above, according to the present invention, by storing the hydraulic pressure of a predetermined pressure or more between the primary pulley and the secondary pulley to supply the stored hydraulic pressure to the pulley side as necessary to assist the oil pump, It is an invention that can be applied to the oil pump to improve fuel economy, light weight and reduce the production cost.

Claims (3)

In a continuously variable transmission for a vehicle such that the speed change is performed in accordance with the diameter displacement of the primary pulley and the secondary pulley mounted on the input shaft and the output shaft, Install a reservoir capable of storing oil between the primary pulley and the secondary pulley, optionally the hydraulic pressure of the secondary pulley to be stored in the reservoir, the control to supply the oil stored in the reservoir to the primary pulley A hydraulic control system for a continuously variable transmission for a vehicle, characterized in that the solenoid valve is arranged to be made. The hydraulic control system of claim 1, wherein the reservoir is formed of a spring and a piston so as to apply pressure to oil stored therein. The method of claim 1, wherein the solenoid ball is a three-way valve, the first port for closing the conduit communicating with the primary pulley and the second pulley, the first connection connecting the pipeline and the reservoir of the primary pulley And a third port connecting the second port and the pipe line of the secondary pulley to the reverser.