Hydraulic control apparatus of continuously variable transmission of hybrid vehicle

A hydraulic control apparatus of a continuously variable transmission of a hybrid vehicle may include a D-N control valve that converts a state, in which a hydraulic pressure is supplied from a line regulator valve to a solenoid feed valve through a second regulator valve according to changes of a driving pulley control pressure and a clutch lubrication control pressure with respect to driven pulley control pressure, and a state, in which the hydraulic pressure from the line regulator valve is directly supplied to the solenoid feed valve, into each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Korean Patent Application Number 10-2008-0113847, filed on Nov. 17, 2008, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a hydraulic control apparatus of a continuously variable transmission that is equipped in a hybrid vehicle, particularly a technology of efficiently generating hydraulic pressure required for a hydraulic control apparatus according to the traveling state of a vehicle.

2. Description of Related Art

FIG. 1shows an example of a hydraulic control apparatus of a continuously variable transmission of a hybrid vehicle, in which hydraulic pressure supplied from an oil pump500is supplied toward a driving pulley504and a driven pulley506after being adjusted at predetermined pressure by a line regulator valve502, the hydraulic pressure supplied toward driving pulley504is adjusted by a transmission gear ratio control valve508and then supplied to driving pulley504, and the hydraulic pressure supplied toward driven pulley506is adjusted by a secondary valve510and then supplied to driven pulley506.

The hydraulic pressure adjusted by line regulator valve502is also supplied to a second regulator valve512, such that second regulator valve512adjusts hydraulic pressure that is supplied to a starting clutch control solenoid valve514, a limp home valve516, and a solenoid feed valve518.

Starting clutch control solenoid valve514controls and supplies operational pressure for a reverse brake520and a forward clutch522, solenoid feed valve518supplies the adjusted hydraulic pressure to a transmission gear ratio control solenoid valve524, a secondary control solenoid valve526, a line regulator solenoid valve528, and a clutch lubrication control solenoid valve530to control transmission gear ratio control valve508, a secondary valve510, line regulator valve502, and a lubrication control valve532, respectively.

The other parts have configurations and functions that are not substantially different from those of hydraulic control apparatuses of continuously variable transmission.

The pressure supplied toward driving pulley504and driven pulley506from line regulator valve502is referred to as ‘pulley pressure’ and the pressure supplied to transmission gear ratio control solenoid valve524, secondary control solenoid valve526, line regulator solenoid valve528, and clutch lubrication control solenoid valve530from solenoid feed valve518is referred to as ‘solenoid valve supply pressure’ herein.

When a vehicle stops in a D-range, other pressure does not substantially need to be supplied than the pulley pressure and the solenoid valve supply pressure required for quick operation when restarting the vehicle; however, existing structures of hydraulic control apparatuses cannot help supplying hydraulic pressure to unnecessary parts, such as the hydraulic pressure supplied toward forward clutch522, which is inefficient.

That is, since hydraulic pressure is supplied to unnecessary parts when a vehicle stops in the D-range, energy is unnecessarily consumed and the efficiency of the continuously variable transmission is decreased.

BRIEF SUMMARY OF THE INVENTION

Various aspects of the present invention are directed to provide a hydraulic control apparatus of a continuously variable transmission of a hybrid vehicle that stops hydraulic pressure supplied to unnecessary parts and automatically ensures a state of supplying only pulley pressure and solenoid valve supply pressure required for quickly restarting a vehicle when the vehicle stops in a D-range, and appropriately supplies hydraulic pressure again to all the parts when restarting the vehicle, thereby improving the efficiency of the continuously variable transmission.

In an aspect of the present invention, a hydraulic control apparatus of a continuously variable transmission of a hybrid vehicle may include a D-N control valve that converts a state, in which a hydraulic pressure is supplied from a line regulator valve to a solenoid feed valve through a second regulator valve according to changes of a driving pulley control pressure and a clutch lubrication control pressure with respect to driven pulley control pressure, and a state, in which the hydraulic pressure from the line regulator valve is directly supplied to the solenoid feed valve, into each other.

The driven pulley control pressure may be exerted in a side of a valve spool of the D-N control valve, and the driving pulley control pressure and the clutch lubrication control pressure may be exerted in the opposite side thereof, such that, in a D-range stop, the valve spool is moved in one direction by the driven pulley control pressure, while in a D-range traveling, the valve spool is moved in the other direction by the driving pulley control pressure and the clutch lubrication control pressure, and a plurality of ports are formed such that, the hydraulic pressure from the line regulator valve is directly supplied to the solenoid feed valve after the valve spool is moved in the one direction and the hydraulic pressure from the line regulator valve is supplied to the solenoid feed valve through the second regulator valve after the valve spool is moved in the other direction.

The D-N control valve may include a valve body having a first port where the driven pulley control pressure adjusted by a second control solenoid valve is supplied, a second port where a hydraulic pressure is supplied from the line regulator valve, a third port connected to the second regulator valve to supply a hydraulic pressure, a fourth port connected to the second regulator valve to receive a hydraulic pressure, a fifth port connected to the solenoid feed valve to supply a hydraulic pressure, a sixth port connected to the line regulator valve to receive a hydraulic pressure, a seventh port where the driving pulley control pressure adjusted by a transmission gear ratio control solenoid valve is supplied, and an eighth port where the clutch lubrication control pressure adjusted by a clutch lubrication control solenoid valve is supplied, which are sequentially formed, and the valve spool integrally having a first land changing communication between the second port and the third port, and a second land and a third land changing communication between the fourth port and the fifth port and between the fifth port and the sixth port, according to changes in the control pressures supplied to the valve body.

In various aspects, the present invention stops hydraulic pressure supplied to unnecessary parts and automatically ensures a state of supplying only pulley pressure and solenoid valve supply pressure required for quickly restarting a vehicle when the vehicle stops in a D-range, and appropriately supplies hydraulic pressure again to all the parts when restarting the vehicle, thereby improving the efficiency of a continuously variable transmission.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIGS. 2 to 4, a hydraulic control apparatus of a continuously variable transmission of a hybrid vehicle includes a D-N control valve7that converts a state in which hydraulic pressure is supplied from a line regulator valve1to a solenoid feed valve5through a second regulator valve3according to changes of driving pulley control pressure and clutch lubrication control pressure with respect to driven pulley control pressure and a state in which the hydraulic pressure from line regulator valve1is directly supplied to solenoid feed valve5, into each other.

The driven pulley control pressure is pressure that a secondary control solenoid valve9that has received the solenoid valve supply pressure from solenoid feed valve5adjusts and outputs to control a driven pulley11through a secondary valve61, and the driving pulley control pressure is pressure that a transmission gear ratio control solenoid valve13that has received the solenoid valve supply pressure from solenoid feed valve5adjusts and outputs to control a driving pulley15through a transmission ratio control valve62.

Further, the clutch lubrication control pressure is pressure that clutch lubrication control solenoid valve17outputs after adjusting solenoid valve supply pressure received from solenoid feed valve5.

When a hybrid vehicle equipped with a continuously variable transmission that has traveled in the D-range is stopped, minimum transmission gear ratio is implemented by minimizing the pressure of driving pulley15and maximizing the pressure of driven pulley11. Accordingly, the driving pulley control pressure for controlling the pressure of driving pulley15is at the minimum and the driven pulley control pressure for controlling pressure of driven pulley11is at the maximum.

Further, when the vehicle stops, the flow rate required for lubricating and cooling forward clutch19is minimized, and a large amount of slip is generated when the vehicle starts, such that the flow rate required for lubrication is maximized.

Driven pulley control pressure is exerted in a side of a valve spool21of D-N control valve7, and the driving pulley control pressure and the clutch lubrication control pressure are exerted in the opposite side, such that, in D-range stop, valve spool21is moved in one direction by the driven pulley control pressure, while in D-range traveling, valve spool21is moved in the other direction by the driving pulley control pressure and the clutch lubrication control pressure.

Ports are formed such that, the hydraulic pressure from line regulator valve1is directly supplied to solenoid feed valve5after valve spool21is moved in one direction and the hydraulic pressure from line regulator valve1is supplied to solenoid feed valve5through second regulator valve3after valve spool21is moved in the other direction.

That is, while a vehicle travels in the D-range, the hydraulic pressure from line regulator valve1is supplied to solenoid feed valve5through second regulator valve3, thereby forming substantially the same hydraulic pipe line as the related art. However, when the vehicle stops in the D-range, the hydraulic pressure from line regulator valve1is directly supplied to solenoid feed valve5and line pressure from line regulator valve1is not supplied to second regulator valve3, such that hydraulic pressure supplied to forward clutch19through second regulator valve3is stopped.

D-N control valve7includes a valve body39having a first port23where the driven pulley control pressure adjusted by second control solenoid valve9is supplied, a second port25where hydraulic pressure is supplied from line regulator valve1, a third port27connected to second regulator valve3to supply hydraulic pressure, a fourth port29connected to second regulator valve3to receive hydraulic pressure, a fifth port31connected to solenoid feed valve5to supply hydraulic pressure, a sixth port33connected to line regulator valve1to receive hydraulic pressure, a seventh port35where the driving pulley control pressure adjusted by transmission gear ratio control solenoid valve13is supplied, and an eighth port37where clutch lubrication control pressure adjusted by clutch lubrication control solenoid valve17is supplied, which are sequentially formed; and valve spool21integrally having a first land41changing communication between second port25and third port27, and a second land43and a third land45changing communication between fourth port29and fifth port31and between fifth port31and sixth port33, according to changes in hydraulic pressure supplied to valve body39,

According to a hydraulic control apparatus of a continuously variable transmission of a hybrid vehicle of the present invention having the above configuration, while a vehicle normally travels in the D-range, as shown inFIG. 2, since the pressure exerted in valve spool21by the driving pulley control pressure and the clutch lubrication control pressure is larger than the driven pulley control pressure, valve spool21of D-N control valve7moves in the other direction (to the left in the figure), the line pressure from line regulator valve1is supplied to second regulator valve3through second port25and third port27of D-N control valve7. Further, second regulator valve3, as in the related art, supplies control pressure to a starting clutch control solenoid valve47and a limp home valve49as well as solenoid feed valve5, such that forward clutch19is operated by pressure controlled by starting clutch control solenoid valve47.

When the vehicle that has traveled as described above stops, the driving pulley control pressure and the clutch lubrication control pressure are minimized due to the above reason and the driven pulley control pressure is maximized, such that valve spool21of D-N control valve7moves opposite to the above case, that is, to the right in the figure and reaches the position shown inFIG. 4.

Therefore, the line pressure supplied from line regulator valve1is not supplied to D-N control valve7through second port25, but supplied to sixth port33and directly supplied to solenoid feed valve5through fifth port31, such that solenoid feed valve5can continuously supply solenoid supply pressure, thereby ensuring normal operations of transmission gear ratio control solenoid valve13, secondary control solenoid valve9, line regulator solenoid valve51, and clutch lubrication control solenoid valve17.

Further, since the hydraulic pressure cannot be supplied from line regulator valve1to second port25, second regulator valve3that has received line pressure through third port27cannot receive the line pressure, and as a result, it is possible to stop unnecessary flow rate supplied toward forward clutch19.

That is, in D-range stop, D-N control valve7is automatically operated, such that the hydraulic pressure supplied toward forward clutch19is stopped, thereby preventing unnecessary consumption of energy and improving the efficiency of the continuously variable transmission.

Further, when the vehicle restarts, the driven pulley control pressure, driving pulley control pressure, and clutch lubrication control pressure exerted in valve spool21of D-N control valve7change, such that valve spool21moves again to the left as shown inFIG. 2. Therefore, appropriate hydraulic pressure can be supplied toward forward clutch19while allowing the normal traveling of the vehicle.

For convenience in explanation and accurate definition in the appended claims, the terms “left” or “right” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.