JP2004124967A - Controller for belt type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the oil balance in idling in a controller of a belt type continuously variable transmission comprising a secondary valve outputting a secondary pressure supplied to a secondary pulley in accordance with a signal pressure of a two-way linear solenoid. <P>SOLUTION: When an idling state is determined, an instruction for maximizing the secondary pressure is output to the two-way linear solenoid, and a drain port of the two-way linear solenoid is closed to reduce the leakage. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for a belt-type continuously variable transmission.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a hydraulic circuit diagram of a belt-type continuously variable transmission mounted on a vehicle, for example, the hydraulic circuit diagram shown in FIG.
[0003]
First, the configuration will be described. The line pressure discharged from the oil pump 22 and regulated by the pressure regulator valve 40 is supplied to the primary pulley cylinder chamber 10c of the primary pulley 10 via the shift control valve 100, and the secondary valve 90 Is supplied to the secondary pulley cylinder chamber 11c of the secondary pulley 11 via the
[0004]
The shift control valve 100 is opened according to the target speed ratio by driving the stepping motor 120, and is closed according to the groove width of the primary pulley 10 when the groove width of the primary pulley 10 reaches the target speed ratio by shifting, The shift is configured to end.
[0005]
The secondary valve 90 outputs a secondary pressure according to the control pressure output from the secondary control valve 80. The secondary control valve 80 is controlled by a signal pressure output from the two-way linear solenoid 70. The signal pressure output from the two-way linear solenoid 70 is controlled by a CVTCU (not shown) according to a target secondary pressure set based on a target gear ratio and an input torque (engine torque).
[0006]
The two-way linear solenoid 70 has one input port and two output ports. The input port is connected to an output port of the pilot valve 50 via an oil passage 51. One of the output ports is connected to a secondary control valve 80 via an oil passage 72, and the other is connected to an oil pan (not shown) as a drain port. Then, the amount of leak from the drain port is changed according to a signal from the CVTCU, and the signal pressure output to the secondary control valve 80 is adjusted.
[0007]
[Problems to be solved by the invention]
Normally, at the time of idling at a low engine speed, control for minimizing the line pressure is performed in order to reduce the engine load, and accordingly control for minimizing the secondary pressure is performed. At this time, in the two-way linear solenoid 70, control is performed such that the drain port is opened to minimize the signal pressure and the leak amount is maximized.
[0008]
However, at the time of idling, the oil discharge flow rate of the oil pump 22 is small, and the oil amount balance of the hydraulic circuit is severe. Therefore, when the control for maximizing the leak amount of the two-way linear solenoid 70 is performed at the time of idling, the oil amount balance is further increased. There is a risk that it will worsen.
[0009]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide a belt type including a secondary valve that outputs a secondary pressure supplied to a secondary pulley in accordance with a signal pressure of a two-way linear solenoid. In a control device for a continuously variable transmission, an object is to improve an oil amount balance during idling.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, in the control device for a belt-type continuously variable transmission according to the first aspect, the primary pulley and the secondary pulley that sandwich the V-belt and the flow rate control are performed such that a target gear ratio based on an operation state is obtained. Speed ratio control means for controlling a primary pressure of the primary pulley via a valve, a secondary valve for outputting a secondary pressure to the secondary pulley, a constant hydraulic pressure as a source pressure, and a secondary pressure for the secondary valve. A two-way linear solenoid that outputs a signal pressure that can be set to the valve, a line pressure control valve that controls a line pressure supplied to the flow control valve and the secondary valve, and a command that opens and closes a drain port of the two-way linear solenoid. And a secondary pressure control means capable of arbitrarily setting a signal pressure, and an idle determination means for determining whether the engine is in an idle state. A control device for a belt-type continuously variable transmission, comprising: a state determination unit; and an idle-time line pressure control unit that outputs a command to minimize the line pressure to a line pressure control valve when the idle state is determined. Wherein the secondary pressure control means outputs a command to close a drain port of the two-way linear solenoid when it is determined that the secondary pressure control means is in an idle state.
[0011]
According to a second aspect of the present invention, in the control device for a belt-type continuously variable transmission according to the first aspect, a hydraulic pressure drained from a line pressure control valve is applied between the two-way linear solenoid and a secondary valve. And a secondary control valve that outputs a control pressure capable of arbitrarily setting the secondary pressure based on a signal pressure output from the two-way linear solenoid for the secondary valve.
[0012]
【The invention's effect】
According to the first aspect of the present invention, the secondary pressure control means outputs a command to close the drain port of the two-way linear solenoid when it is determined that the secondary pressure is in the idle state. That is, the spool of the two-way linear solenoid moves in the direction to close the drain port. Therefore, the amount of leakage from the drain port can be reduced as compared with the related art, so that the oil amount balance during idling can be improved.
[0013]
Note that by closing the drain port, the signal pressure output from the two-way linear solenoid becomes maximum, and in response to this, a command to output the secondary pressure to the maximum is output to the secondary valve. Since the control is performed by the control means so as to be minimum, the secondary pressure does not exceed the line pressure, and the supply of the excessive clamping pressure to the secondary pulley is avoided.
[0014]
According to the second aspect of the present invention, a belt-type continuously variable transmission having a configuration in which a secondary control valve is provided between the two-way linear solenoid and the secondary valve for the purpose of downsizing the two-way linear solenoid, improving responsiveness, and the like. By closing the drain port of the two-way linear solenoid at idle, the amount of leakage from the drain port of the secondary control valve as well as the two-way linear solenoid can be minimized. Can be improved.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, the configuration will be described.
FIG. 1 is a schematic configuration diagram of a V-belt type continuously variable transmission.
[0016]
In FIG. 1, a continuously variable transmission 5 is connected to an engine 1 via a torque converter 2 having a lock-up clutch and a forward / reverse switching mechanism 4, and includes a primary pulley 10 on an input shaft side and an output shaft 13 as a pair of variable pulleys. Is provided with a secondary pulley 11 connected to the secondary pulley. The pair of variable pulleys 10 and 11 are connected by a V-belt 12. The output shaft 13 is connected to the differential 6 via an idler gear 14 and an idler shaft.
[0017]
The gear ratio of the continuously variable transmission 5 and the contact frictional force of the V-belt are controlled by a hydraulic control unit (hydraulic CU) 30 that responds to a command from a CVT control unit (CVTCU) 20. The CVTCU 20 determines and controls a gear ratio and a contact friction force based on input torque information from an engine control unit (ECU) 21 that controls the engine 1 and outputs from sensors and the like described below.
[0018]
The primary pulley 10 of the continuously variable transmission 5 has a fixed conical plate 10b that rotates integrally with the input shaft, a V-shaped pulley groove disposed opposite to the fixed conical plate 10b, and a primary pulley cylinder. It is composed of a movable conical plate 10a that can be displaced in the axial direction by hydraulic pressure (primary pressure) acting on the chamber 10c.
[0019]
On the other hand, the secondary pulley 11 has a fixed conical plate 11b that rotates integrally with the output shaft 13 and a V-shaped pulley groove that is disposed to face the fixed conical plate 11b, and is connected to the secondary pulley cylinder chamber 11c. It is composed of a movable conical plate 11a that can be displaced in the axial direction according to the hydraulic pressure (secondary pressure) that acts.
[0020]
Here, the primary pulley cylinder chamber 10c and the secondary pulley cylinder chamber 11c are set to have the same pressure receiving area.
[0021]
The drive torque input from the engine 1 is input to the continuously variable transmission 5 via the torque converter 2 and the forward / reverse switching mechanism 4 and transmitted from the primary pulley 10 to the secondary pulley 11 via the V-belt 12. At this time, the movable conical plate 10a of the primary pulley 10 and the movable conical plate 11a of the secondary pulley 11 are displaced in the axial direction to change the contact radius with the V-belt 12, so that the gear ratio between the primary pulley 10 and the secondary pulley 11 is changed. Can be changed continuously.
[0022]
The gear ratio of the continuously variable transmission 5 and the contact frictional force of the V-belt 12 are controlled by the hydraulic CU 30.
[0023]
FIG. 2 is a hydraulic circuit diagram of the V-belt type continuously variable transmission.
In the figure, reference numeral 40 denotes a pressure regulator valve for adjusting the discharge pressure of the oil pump 22 supplied from the oil passage 41 as a line pressure (pulley clamp pressure). An oil passage 42 communicates with the oil passage 41. The oil passage 42 is a pulley clamp pressure supply oil passage that supplies a pulley clamp pressure for clamping the belt 12 to the primary pulley cylinder chamber 10c and the secondary pulley cylinder chamber 11c of the continuously variable transmission 5. The oil passage 43 connected to the oil passage 42 supplies the original pressure of the pilot valve 50.
[0024]
The hydraulic pressure drained from the pressure regulator valve 40 is supplied to a clutch regulator valve 60 that controls the forward / reverse switching mechanism 4 (see FIG. 1) via an oil passage 46. The oil passage 46 communicates with the oil passage 42 via an oil passage 44 having an orifice 45. Clutch regulator valve 60 regulates the oil pressure in oil passage 46 and oil passage 61. The oil pressure in the oil passage 61 is supplied to the secondary control valve 80 and a select switching valve (not shown).
[0025]
The pilot valve 50 sets a constant supply pressure of the two-way linear solenoid 70 via the oil passage 51. The output pressure (signal pressure) of the two-way linear solenoid 70 is supplied to the secondary control valve 80 to control the operation of the secondary control valve 80.
[0026]
An oil passage 72 is connected to the secondary control valve 80 as an input port to supply a signal pressure from the two-way linear solenoid 70 by reducing the pressure through the orifice 73, and communicates with the oil passage 61 regulated by the clutch regulator valve 60. Oil path 74 is connected. Further, an oil passage 81 for supplying a control pressure to the secondary valve 90 is connected as an output port.
[0027]
The oil passage 81 connected to the output port of the secondary control valve 80 and having an orifice 82 and the oil passage 44 communicating with the oil passage 42 regulated by the pressure regulator valve 40 are connected to the secondary valve 90 as input ports. ing. Further, an oil passage 91 for supplying a secondary pressure to the secondary pulley cylinder chamber 11c of the secondary pulley 11 is connected as an output port.
[0028]
The shift control valve 100 is connected as an input port to an oil passage 47 communicating with the oil passage 42 regulated by the pressure regulator valve 40. On the other hand, an oil passage 101 for supplying a primary pressure to the primary pulley cylinder chamber 10c of the primary pulley 10 is connected as an output port.
[0029]
The shift control valve 100 is connected to a servo link 110 constituting a mechanical feedback mechanism, is driven by a stepping motor 120 connected once to the servo link 110, and is connected to a primary pulley 10 connected to the other end of the servo link 110. The feedback of the groove width, that is, the actual gear ratio is received from the movable conical plate 10a.
[0030]
Next, the operation will be described.
[Normal shift control process]
The normal shift control by the CVTCU 20 will be described with reference to the flowchart of FIG.
[0031]
First, in step S1, the actual gear ratio is calculated from the ratio between the primary pulley rotation speed detected by the primary pulley speed sensor 26 and the secondary pulley rotation speed detected by the secondary pulley speed sensor 27.
[0032]
In step S2, the input torque to the continuously variable transmission 5 is calculated from the input torque information from the ECU 21. The input torque information includes, for example, the fuel injection amount (injection pulse width) of the engine 1 and the engine speed.
[0033]
Next, in step S3, based on the actual gear ratio and the input torque, a required secondary pressure (required secondary pressure) is calculated with reference to the map of FIG.
In this map, the lower the speed ratio (Od side), the lower the hydraulic pressure, and the higher the speed ratio (Lo side), the higher the hydraulic pressure. If the input torque is large, the hydraulic pressure is high, and if the input torque is small, The hydraulic pressure is set low, and is set in advance.
[0034]
In step S4, a required primary pressure (required primary pressure) is calculated based on the actual gear ratio and the input torque with reference to the map of FIG.
In this map, the lower the speed ratio, the lower the hydraulic pressure, the higher the hydraulic pressure, the higher the hydraulic pressure, and the higher the input torque, the higher the hydraulic pressure, and the lower the input torque, the lower the hydraulic pressure. Thus, the gear ratio is set to be relatively high on the small side of the gear ratio and relatively low on the large side of the gear ratio. However, the magnitude relationship between the required primary pressure and the required secondary pressure may be reversed depending on the input torque.
[0035]
Next, in step S5, the primary pressure operation amount, which is the target value of the primary pressure, is calculated by the following equation.
Primary pressure operation amount = Necessary primary pressure + offset amount Here, the offset amount is a value (added value of hydraulic pressure) set according to the characteristics of the shift control valve 100, and the characteristic of pressure loss is completely changed to hydraulic pressure. Since it is not proportional, it is a value that compensates for this.
[0036]
In step S6, the magnitude relationship between the primary pressure manipulated variable and the required secondary pressure obtained in step S3 is compared and determined. When the primary pressure operation amount is larger, the process proceeds to step S7, and when the required secondary pressure is equal to or more than the primary pressure operation amount, the process proceeds to step S8.
[0037]
In step S7, the control is terminated the line pressure operation quantity is a target value of the line pressure P _L as a primary pressure operation quantity.
[0038]
In step S8, this control is ended with the line pressure operation amount as a necessary secondary pressure.
[0039]
As described above, after the larger of the primary pressure operation amount and the required secondary pressure is determined as the line pressure operation amount (target oil pressure), the control amount (such as the duty signal) for driving the solenoid of the pressure regulator valve 40 is determined. After the conversion, the pressure regulator valve 40 is driven.
[0040]
[Idle line pressure minimum control processing]
FIG. 6 is a flowchart showing the flow of the idle-time line pressure minimum control process in the CVTCU 20.
[0041]
In step S21, a vehicle speed and an idle signal are read from the vehicle speed sensor 33 and the idle switch 32.
[0042]
In step S22, it is determined whether the vehicle is in the idle state based on the read vehicle speed and the idle signal. If the vehicle speed is 0 and the idle switch is ON, it is determined that the vehicle is in an idle state, and the process proceeds to step S23. Otherwise, it is determined that the vehicle is not in the idle state, and the control ends.
[0043]
In step S23, it outputs a command to the line pressure P _L to the minimum to the pressure regulator valve 40.
[0044]
In step S24, a command to maximize the secondary pressure is output to the two-way linear solenoid 70, and the control ends.
[Idle line pressure minimum control processing operation]
FIG. 7 is a time chart showing the operation of the line pressure minimum control at the time of idling.
[0045]
At the instant t1, the driver has released his / her foot from the accelerator pedal, and the idle switch 32 is turned on.
[0046]
At the instant t2, since the vehicle becomes the vehicle speed is 0 to stop, the command to minimize the line pressure P _L is output from the CVTCU20 to the pressure regulator valve 40. At the same time, a command for maximizing the secondary pressure is output from the CVTCU 20 to the two-way linear solenoid 70.
[0047]
At this time, in the two-way linear solenoid 70, control is performed to close the drain port and maximize the signal pressure output to the secondary control valve 80 in order to maximize the secondary pressure. On the other hand, the secondary control valve 80 also performs control to close the drain port and maximize the control pressure output to the secondary valve 90.
[0048]
At the instant t3, the driver for carrying the foot on the accelerator pedal, the idle switch 32 is turned OFF, is switched to the line pressure P _L control based on the normal target speed ratio.
[0049]
Next, effects will be described.
Since the V-belt type continuously variable transmission of the present embodiment, the time of performing the control for minimizing the line pressure P _L when idle, it was decided for outputting a command to the maximum secondary pressure 2-way linear solenoid 70, 2 The amount of leakage between the linear solenoid 70 and the secondary control valve 80 is minimized, and the oil balance at idle can be improved as compared with the related art.
[0050]
The embodiment of the present invention has been described above. However, the specific configuration of the present invention is not limited to the present embodiment, and even if there is a design change or the like within a range not departing from the gist of the present invention, the present invention is not limited thereto. Included in the invention.
[0051]
For example, in the present embodiment, an example in which the idle state is determined from the output signal of the vehicle speed sensor 33 and the idle switch 32 has been described. .
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a V-belt type continuously variable transmission.
FIG. 2 is a hydraulic circuit diagram of a V-belt type continuously variable transmission.
FIG. 3 is a flowchart showing a flow of hydraulic control performed by a pulley pressure control unit of the CVT control unit.
FIG. 4 is a map of a required secondary pressure according to a gear ratio and an input torque.
FIG. 5 is a map of a required primary pressure according to a gear ratio and an input torque.
FIG. 6 is a flowchart showing a flow of an idle line pressure minimum control process.
FIG. 7 is a time chart showing an operation of the line pressure minimum control processing at the time of idling.
[Explanation of symbols]
Reference Signs List 1 engine 2 torque converter 4 forward / reverse switching mechanism 5 continuously variable transmission 6 differential 10 primary pulley 10a movable conical plate 10b fixed conical plate 10c primary pulley cylinder chamber 11 secondary pulley 11a movable conical plate 11b fixed conical plate 11c secondary pulley cylinder chamber 12 Belt 13 Output shaft 14 Idler gear 22 Oil pump 24 Operation amount sensor 26 Primary pulley speed sensor 27 Secondary pulley speed sensor 32 Idle switch 33 Vehicle speed sensor 40 Pressure regulator valve 41 Oil passage 42 Oil passage 43 Oil passage 44 Oil passage 45 Orifice 46 Oil passage 47 oil passage 50 pilot valve 51 oil passage 60 clutch regulator valve 61 oil passage 70 two-way linear solenoid 72 oil passage 73 orifice 4 oil passage 80 secondary control valve 81 oil passage 82 orifice 90 secondary valve 91 oil passage 100 shift control valve 101 oil passage 110 the servo link 120 stepper motor

Claims (2)

A primary pulley and a secondary pulley for holding the V-belt,
Speed ratio control means for controlling a primary pressure of the primary pulley via a flow control valve so as to have a target speed ratio based on an operation state;
A secondary valve that outputs a secondary pressure to the secondary pulley,
A two-way linear solenoid that outputs a signal pressure capable of arbitrarily setting the secondary pressure to the secondary valve with a constant hydraulic pressure as a base pressure,
A line pressure control valve for controlling a line pressure supplied to the flow control valve and the secondary valve,
Secondary pressure control means for outputting a command to open and close the drain port of the two-way linear solenoid, and capable of arbitrarily setting a signal pressure;
Idle state determining means for determining whether the engine is in an idle state, and idle line pressure controlling means for outputting a command to minimize the line pressure to the line pressure control valve when it is determined that the engine is in an idle state;
In the control device of the belt-type continuously variable transmission having
The control device for a belt-type continuously variable transmission, wherein the secondary pressure control unit outputs a command to close a drain port of the two-way linear solenoid when it is determined that the secondary pressure control unit is in an idle state. The control device for a belt-type continuously variable transmission according to claim 1, wherein a hydraulic pressure drained from a line pressure control valve is used as an original pressure between the two-way linear solenoid and a secondary valve, A control device for a belt-type continuously variable transmission, comprising: a secondary control valve that outputs a control pressure capable of arbitrarily setting a secondary pressure based on a signal pressure output from a linear solenoid.

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