JP2003227562A - Controller of driving system including continuously variable transmission - Google Patents

Controller of driving system including continuously variable transmission

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Publication number
JP2003227562A
JP2003227562A JP2002027417A JP2002027417A JP2003227562A JP 2003227562 A JP2003227562 A JP 2003227562A JP 2002027417 A JP2002027417 A JP 2002027417A JP 2002027417 A JP2002027417 A JP 2002027417A JP 2003227562 A JP2003227562 A JP 2003227562A
Authority
JP
Japan
Prior art keywords
clutch
engagement pressure
control
continuously variable
torque
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP2002027417A
Other languages
Japanese (ja)
Other versions
JP4126916B2 (en
Inventor
Kazumi Hoshiya
Kunihiro Iwatsuki
Yasunori Nakawaki
Takahiro Oshiumi
康則 中脇
邦裕 岩月
一美 星屋
恭弘 鴛海
Original Assignee
Toyota Motor Corp
トヨタ自動車株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toyota Motor Corp, トヨタ自動車株式会社 filed Critical Toyota Motor Corp
Priority to JP2002027417A priority Critical patent/JP4126916B2/en
Priority claimed from US10/356,599 external-priority patent/US6974009B2/en
Publication of JP2003227562A publication Critical patent/JP2003227562A/en
Application granted granted Critical
Publication of JP4126916B2 publication Critical patent/JP4126916B2/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16HGEARING
    • F16H61/00Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/66Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings
    • F16H2061/6604Special control features generally applicable to continuously variable gearings
    • F16H2061/6618Protecting CVTs against overload by limiting clutch capacity, e.g. torque fuse

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately set a clutch engaging pressure for providing a predetermined gain to a transmission torque of a clutch disposed in series with a continuously variable transmission. <P>SOLUTION: The continuously variable transmission is connected to the clutch in torque series. A controller of a driving system including the continuously variable transmission sets a gain of the transmission torque of the clutch until slip occurs in the clutch to be smaller than that of the continuously variable transmission until slip occurs in the transmission. The controller comprises an engaging pressure decreasing means (step S106) for decreasing engaging pressure of the clutch in the engaging state until the slip occurs in the clutch, a re-engaging means for re-engaging the clutch by increasing the engaging pressure after detecting the slip of the clutch, and an engaging pressure setting means for setting, as the engaging pressure of the clutch, a pressure obtained by adding a predetermined value for providing the gain to the transmission torque of the clutch to the engaging pressure in re-engaging the clutch. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque transmitting member such as a belt or a power roller that directly or indirectly makes contact with a rotating member such as a pulley or a disk to transmit torque according to contact pressure. The present invention relates to a control device for a drive system including a continuously variable transmission mechanism whose capacity changes, and more particularly to a control device for controlling the engagement pressure of a clutch arranged in series with the continuously variable transmission mechanism.

[0002]

2. Description of the Related Art A continuously variable transmission mechanism continuously changes the contact position or torque transmission position between a member such as a belt or a power roller that mediates the transmission of torque and a pulley or a disk to continuously change the gear ratio. Is configured to change. The transmission of the torque is performed by utilizing the frictional force or the shearing force of the traction oil. Therefore, exceeding the torque capacity determined based on the contact pressure between the member that transmits torque and the pulley or the disc or the pressure that sandwiches the member that transmits torque (that is, the clamping pressure) and the friction coefficient or the shearing force of the traction oil. When the torque acts, the belt and the power roller slip.

When the belt and the power roller slip excessively, the pulley and the disk are worn, and as a result, torque cannot be transmitted at the worn portion, and the function of the continuously variable transmission mechanism cannot be achieved. Therefore, in order to prevent slippage in the continuously variable transmission mechanism while the vehicle equipped with the continuously variable transmission mechanism is running, it is conceivable to increase the clamping pressure to increase the torque capacity.

However, if the clamping pressure is increased, the efficiency of power transmission in the continuously variable transmission mechanism is lowered, and a large amount of power is consumed to drive the oil pump for generating hydraulic pressure. Fuel efficiency deteriorates. Therefore, it is preferable that the clamping force of the continuously variable transmission be as low as possible within the range where slippage does not occur.

In this case, the torque acting on the continuously variable transmission mechanism cannot be predicted in an unsteady running state in which the output torque of the engine and the negative torque on the wheel side change frequently or largely, so that the safety factor or the torque cannot be predicted. There is no choice but to increase the capacity margin (the excess amount of the torque capacity with respect to the minimum or limit torque capacity at which slippage does not occur in a steady state) to set the clamping pressure to a certain degree. On the other hand, in a steady or quasi-steady running state, the torque acting on the continuously variable transmission mechanism is stabilized, so that the clamping pressure can be reduced to a state just before slippage occurs.

However, since unexpected torque may occur even in a steady or quasi-steady running state, even in that case, it is necessary to prevent or avoid slippage of the continuously variable transmission mechanism. Therefore, for example, in the invention disclosed in Japanese Patent Laid-Open No. 10-2930, a clutch is arranged in series with the continuously variable transmission mechanism, and the margin of the engaging force of the clutch is set to be smaller than the margin of the clamping pressure in the continuously variable transmission mechanism. When the slip of the clutch is not detected, the engaging force and the pinching pressure are decreased, and when the slip of the clutch is detected, the engaging force and the pinching pressure are both controlled to be increased. I am configuring. Here, the margin of the engagement pressure or the clamping pressure is an excess amount with respect to the minimum or the limit of the engagement pressure or the clamping pressure that does not cause the slip in the steady state.

This is because when the torque acting on the drive system in which the clutch and the continuously variable transmission mechanism are arranged in series is increased, the clutch is preferentially slid to limit the torque acting on the continuously variable transmission mechanism. As a result, the control is performed to prevent slippage of the continuously variable transmission mechanism.

[0008]

However, in the invention described in the above publication, when the slip of the clutch is not detected, the engaging force of the clutch and the clamping pressure of the continuously variable transmission mechanism are reduced, and as a result, When the slippage of the clutch is detected, the engaging force of the clutch and the clamping force of the continuously variable transmission mechanism are increased. Therefore, the engaging force and the clamping force are repeatedly decreased and increased, and accordingly, the clutch force is increased. Sliding will occur repeatedly. Therefore, in the above-described conventional control device, there is a possibility that the power transmission efficiency in the drive system is reduced, the fuel consumption is deteriorated, or the fuel consumption improving effect by adopting the continuously variable transmission mechanism is impaired.

Further, the control of the engagement force of the clutch has an unavoidable variation due to the characteristics of the hydraulic control device and the individual difference of the friction coefficient of the clutch. However, since the variation of this kind is not taken into consideration when increasing the engagement pressure and the clamping pressure after detecting the slip of the clutch, the engagement pressure of the clutch may be relatively excessive. In such a case, the margin of the clutch engagement pressure may become equal to or exceed the margin of the clamping pressure of the continuously variable transmission, which may cause slippage in the continuously variable transmission. There is.

The present invention has been made by paying attention to the above technical problem, and the margin of the transmission torque of the clutches arranged in series with respect to the continuously variable transmission is determined by the transmission torque of the continuously variable transmission. It is an object of the present invention to provide a control device that can be stably set to a relatively small state with respect to the margin.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a clutch engagement in which there is no margin of transmission torque (torque capacity) with respect to the torque applied to the clutch. The present invention is characterized in that the pressure is obtained and a pressure obtained by adding a value corresponding to a predetermined margin of the transmission torque to the engagement pressure is set as the engagement pressure of the clutch. More specifically, the invention of claim 1 is
The continuously variable transmission mechanism and the clutch are connected in series with each other in the torque transmission direction, and the margin of the transmission torque of the clutch until the clutch slips is determined by the clutch until the slip occurs in the continuously variable transmission mechanism. In a control system for a drive system including a continuously variable transmission mechanism that is set to be smaller than a margin of transmission torque of the continuously variable transmission mechanism, an engagement pressure for reducing the engagement pressure of the engaged clutch until the clutch slips. Lowering means, re-engagement means for re-engaging the clutch by increasing the engagement pressure after the slip of the clutch is detected, and engagement pressure when the clutch is re-engaged. An engagement pressure setting means for setting a pressure obtained by adding a predetermined value for giving the margin to the transmission torque as an engagement pressure of the clutch.

In the invention of claim 1, the margin of the transmission torque is an excess amount of the transmission torque with respect to the minimum transmission torque at which slipping does not occur in a steady state, and "the clutch until slipping occurs in the clutch". The transmission torque margin of is set to be smaller than the transmission torque margin of the continuously variable transmission until slippage occurs at the continuously variable transmission ''. Each transmission torque is set so that the clutch slips before the mechanism. Therefore, in the invention of claim 1, the engagement pressure of the engaged clutch is reduced, and when the slip is detected, the engagement pressure is increased to reengage the clutch. And when the clutch reengages,
A predetermined value corresponding to a predetermined margin of transmission torque is added to the engagement pressure at that time, and the engagement pressure of the clutch is set with the pressure. Therefore, when a state in which the clutch does not slip is set by allowing the transmission torque to have a predetermined margin, the engagement pressure will not be reduced thereafter. As a result, clutch slippage does not occur repeatedly.

The invention according to claim 2 is characterized in that the engagement pressure reducing means according to claim 1 has a plurality of stages in which the reduction rate of the engagement pressure is different and the reduction rate decreases as the engagement pressure decreases. The control device is configured to reduce the engagement pressure after that.

Therefore, according to the second aspect of the invention, when the engagement pressure of the clutch in the engaged state is reduced, the rate of decrease of the engagement pressure thereafter becomes greater than the rate of decrease at the start of the reduction. Therefore, the responsiveness of the engagement pressure reduction control that causes slippage in the clutch is improved, and the clutch is prevented from slipping excessively by avoiding the so-called undershoot of the engagement pressure reduction. Shock is prevented or suppressed.

Further, in the invention of claim 3, the engagement pressure reducing means in the invention of claim 2 sets the transmission torque of the continuously variable transmission mechanism as the engagement pressure set before the clutch slips. The control device is configured to set an engagement pressure that does not cause slippage in the clutch, based on an input torque of a continuously variable transmission mechanism that is obtained based on a set clamping pressure.

Therefore, in the third aspect of the invention, the engagement pressure set in the process of lowering the engagement pressure so that the clutch slips is the engagement pressure based on the input torque of the continuously variable transmission mechanism. . Therefore, if the clamping pressure that determines the transmission torque of the continuously variable transmission is high for some reason,
Accordingly, the engagement pressure of the clutch is set high, and as a result, the desired engagement pressure reduction control can be rapidly advanced without causing slippage in the clutch in the process of reducing the engagement pressure. .

Furthermore, the invention of claim 4 is the same as claim 2
In the invention, the engagement pressure lowering means transmits the torque actually input to the clutch as the engagement pressure set before lowering the engagement pressure at the final stage so that the clutch slips. The engagement pressure required for the operation is set based on the engagement pressure at the time of normal engagement control in which the reduction control by the engagement pressure reducing means is not performed. It is a control device that operates.

Therefore, in the invention of claim 4, in the process of lowering the engagement pressure so as to cause the clutch to slip,
The engagement pressure set immediately before the reduction control at the final stage leading to the slip of the clutch is corrected based on the engagement pressure in the normal engagement control that does not involve the reduction control of the clutch. Therefore, the engagement pressure can be brought close to the actually required engagement pressure of the clutch, and as a result, the engagement pressure can be rapidly reduced within a range where the clutch does not slip.

According to a fifth aspect of the present invention, the engagement pressure setting means according to the first aspect of the present invention allows the engagement pressure when the clutch is re-engaged so that the transmission torque of the clutch has no margin. The control device is characterized in that the engagement pressure of the clutch is a pressure obtained by adding the predetermined value that gives a predetermined margin to the transmission torque to the engagement pressure.

Therefore, in the fifth aspect of the present invention, after the engagement pressure with which the transmission torque of the clutch has no margin is clarified, the clutch is engaged with the engagement pressure obtained by adding a predetermined value for the margin to the engagement pressure. To be made. Therefore, the margin in the transmission torque of the clutch is optimized.

Further, the invention of claim 6 is characterized in that, in the invention of claim 1, it further comprises learning means for learning an engagement pressure at which a margin of the transmission torque of the clutch reaches the predetermined value. It is a control device.

Therefore, in the sixth aspect of the invention, the engagement pressure that gives a predetermined margin to the transmission torque of the clutch is obtained based on learning. Therefore, the engagement pressure reflects an actual state such as an individual difference of the clutch and a change over time, and the margin of the transmission torque of the clutch is optimized accordingly.

The invention of claim 7 is the same as that of claim 6.
In the invention, when the engagement pressure of the clutch is reduced to the engagement pressure based on the learning value obtained by the learning means,
The control device further comprises means for performing a smoothing control to reduce the engagement pressure.

Therefore, in the invention of claim 7, the engagement pressure of the clutch to be reduced and set is known as a learning value, and the engagement pressure of the engaged clutch is set to the learning value obtained by the learning. When the value is reduced to the base value, the value is gradually reduced by the control that has been subjected to the smoothing process without being rapidly reduced. As a result, situations such as undershoot of the engagement pressure and disengagement of the clutch due to the undershoot are avoided.

Further, in the invention of claim 8 according to the invention of claim 6, the learning means is configured to learn the engagement pressure for each operating state, and the learning of the engagement pressure is completed. When the operating state changes between the operating state in which the engagement pressure has been learned and the operating state in which the learning of the engagement pressure has not ended, the content of the control of the engagement pressure to be performed next according to the control state of the engagement pressure at that time is displayed. The control device further comprises a determining unit.

Therefore, in the invention of claim 8, the process of lowering the engagement pressure of the engaged clutch to cause slippage, the process of increasing the engagement pressure of the slipped clutch, and the reengagement of the clutch. When the operating state of the drive system changes between the state where the learning value is obtained and the state where the learning value is not obtained, the next control content is based on the engagement pressure control state at that time. It is determined. Therefore, when the operating state in which the learned value is obtained is changed, it is possible to control the engagement pressure using the learned value, and unnecessary control is omitted. On the contrary, when the driving state is changed so that the learning value is not obtained, the learning value can be obtained.

According to a ninth aspect of the present invention, the re-engaging means in the sixth aspect of the invention is in a state where the engagement pressure of the clutch is reduced by the engagement pressure reducing means or the clutch is re-engaged. When slippage of the clutch is detected in a state where the combined engagement pressure is maintained, the engagement pressure is increased to reengage the clutch, and the engagement pressure of the learning unit is increased. A control device comprising means for prohibiting learning.

Therefore, in the ninth aspect of the present invention, when the clutch slips during the process of controlling the clutch engagement pressure to an engagement pressure with a certain margin in the transmission torque, the clutch is re-engaged. Thus, the engagement pressure is increased and learning of the engagement pressure is prohibited. Therefore, excessive slippage of the clutch is avoided, and at the same time, erroneous learning of the engagement pressure is avoided.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described based on specific examples. First, a drive system including a continuously variable transmission mechanism which is a target of the present invention will be described. The present invention can be applied to a drive system mounted on a vehicle, and the continuously variable transmission mechanism included in the drive system is , A belt type continuously variable transmission mechanism using a belt as a torque transmission member, or a toroidal type (traction type) continuously variable transmission that uses a power roller as a torque transmission member and uses the shear force of oil (traction oil) to transmit torque It is a speed change mechanism. In FIG.
1 schematically shows an example of a vehicle drive system including a belt type continuously variable transmission mechanism 1. This continuously variable transmission mechanism 1 includes a power source 4 via a forward / reverse switching mechanism 2 and a torque converter 3.
Are linked to.

The power source 4 is the same as the power source mounted on a general vehicle, and includes an internal combustion engine such as a gasoline engine, a diesel engine or a natural gas engine, an electric motor, or an internal combustion engine and an electric motor. It is possible to employ a mechanism or the like in which In the following description, the power source 4 will be referred to as the engine 4.

The torque converter 3 connected to the output shaft of the engine 4 has the same structure as the torque converter used in the conventional general vehicle, and the pump is attached to the front cover 5 to which the output shaft of the engine 4 is connected. The impeller 6 is integrated, and a turbine runner 7 facing the pump impeller 6 is arranged adjacent to the inner surface of the front cover 5. The pump impeller 6 and the turbine runner 7 are provided with a large number of blades (not shown). When the pump impeller 6 rotates, a spiral flow of fluid is generated and the spiral flow is generated. The turbine runner 7 is rotated by applying a torque to the turbine runner 7.

Further, a stator 8 for selectively changing the flow direction of the fluid sent from the turbine runner 7 and allowing it to flow into the pump impeller 6 is arranged at the inner peripheral portions of the pump impeller 6 and the turbine runner 7. Has been done. The stator 8 is connected to a predetermined fixed portion 10 via a one-way clutch 9.

The torque converter 3 has a lockup clutch 11 corresponding to the clutch of the present invention. The lockup clutch 11 is arranged in parallel to a substantial torque converter including a pump impeller 6, a turbine runner 7, and a stator 8. The lockup clutch 11 faces the inner surface of the front cover 5 and is the turbine runner. 7 and is pressed against the inner surface of the front cover 5 by hydraulic pressure,
The torque is directly transmitted from the front cover 5 which is an input member to the turbine runner 7 which is an output member. The torque capacity of the lockup clutch 11 can be controlled by controlling the hydraulic pressure.

The forward / reverse switching mechanism 2 is a mechanism adopted because the rotation direction of the engine 4 is limited to one direction, and outputs the input torque as it is and outputs it by reversing it. Is configured to. In the example shown in FIG. 8, a double pinion type planetary gear mechanism is adopted as the forward / reverse switching mechanism 2.

That is, the ring gear 13 is arranged concentrically with the sun gear 12, and between the sun gear 12 and the ring gear 13, the pinion gear 14 meshed with the sun gear 12, the pinion gear 14 and the other pinion gear 15 meshed with the ring gear 13. And the pinion gears 14 and 15 are rotatably and revolvably held by the carrier 16. A forward clutch 17 that integrally connects the two rotating elements (specifically, the sun gear 12 and the carrier 16) is provided, and by selectively fixing the ring gear 13, the direction of the output torque is obtained. A reverse brake 18 for reversing is provided.

The continuously variable transmission mechanism 1 has the same structure as that of a conventionally known belt type continuously variable transmission mechanism, in which a driving pulley 19 and a driven pulley 20 arranged in parallel with each other have a fixed sheave and a fixed sheave, respectively. Hydraulic actuator 21,
And a movable sheave that is moved back and forth in the axial direction by 22. Therefore each pulley 19,
The groove width of 20 changes by moving the movable sheave in the axial direction, and accordingly, the winding radius of the belt 23 wound around each pulley 19, 20 (effective diameter of the pulleys 19, 20) continuously. It changes so that the gear ratio changes steplessly. The drive pulley 19 is the carrier 16 which is an output element of the forward / reverse switching mechanism 2.
Are linked to.

The hydraulic actuator 22 in the driven pulley 20 receives hydraulic pressure (line pressure or its correction pressure) corresponding to the torque input to the continuously variable transmission mechanism 1 via a hydraulic pump and hydraulic control device (not shown). Is being supplied. Therefore, each sheave in the driven pulley 20 sandwiches the belt 23, so that the belt 23
Tension is applied to each pulley 19, 20 and belt 15
The pinching pressure (contact pressure) between and is secured. In other words, the torque capacity according to the clamping force is set. On the other hand, the hydraulic actuator 21 in the drive pulley 19 is supplied with pressure oil according to the gear ratio to be set, and the groove width (effective diameter) according to the target gear ratio.
Is set to.

A driven pulley 20 which is an output member of the continuously variable transmission 1 is connected to a gear pair 24 and a differential 25, and the differential 25 is connected to left and right drive wheels 26.

Various sensors are provided for detecting the operating state (running state) of a vehicle equipped with the continuously variable transmission 1 and the engine 4 described above. That is, the rotation speed of the engine 4 (the input rotation speed of the lockup clutch 11)
Engine speed sensor 2 that detects the engine and outputs a signal
7, turbine rotation speed sensor 28 that detects the rotation speed of turbine runner 7 (output rotation speed of lockup clutch 11) and outputs a signal, input rotation speed sensor that detects the rotation speed of drive pulley 19 and outputs a signal 29, an output rotation speed sensor 30 that detects the rotation speed of the driven pulley 20 and outputs a signal is provided.

Control of engagement / release of the forward clutch 17 and the reverse brake 18 and the belt 23
The electronic control unit (CVT) for the transmission for controlling the clamping force of the clutch, controlling the torque capacity including engagement / disengagement of the lockup clutch 11, and controlling the gear ratio.
-ECU) 31 is provided. This electronic control unit 3
1 is composed mainly of a microcomputer as an example, performs calculations according to a predetermined program based on input data and previously stored data, and various states such as forward and reverse or neutral, and required. It is configured to execute control such as setting of clamping pressure and setting of gear ratio. Further, an electronic control unit for an engine (E
-ECU) 32 is provided, and these electronic control units 3
Data is communicated between 1 and 32.

Next, an example of control executed by the control device of the present invention will be described for a drive system including the continuously variable transmission mechanism 1 described above. 1 to 6 are flowcharts showing an example of the control, and FIG. 7 determines the rotational speed, the engagement pressure (hydraulic pressure) of the lockup clutch 11, and the transmission torque of the continuously variable transmission 1 when the control is executed. 7 is a time chart showing changes in belt clamping pressure.

In the control device of the present invention, the margin of the transmission torque (torque capacity) of the clutch arranged in series with the continuously variable transmission is set smaller than the margin of the transmission torque (torque capacity) of the continuously variable transmission. It is a control device for performing.
The "margin" is the width or difference of the transmission torque that exceeds the minimum transmission torque at which slippage does not occur in the steady state. Therefore, even if the positive torque or the negative torque changes within the margin, the lockup clutch 11 and the continuously variable transmission mechanism 1 do not slip. When the positive torque or the negative torque changes beyond the margin, the clutch slips before the continuously variable transmission mechanism and functions as a so-called torque fuse.

In the present invention, the lockup clutch 11
Engagement pressure (hydraulic pressure) to give a margin to the transmission torque of
When setting the, first, lock-up clutch 11
The control starts from the fact that is controlled to be stable on.
This is the precondition for the control. Therefore, as shown in FIG. 1, first, it is judged whether the precondition for the control is satisfied (step S101).

Here, "stable ON control" means that the engagement pressure for maintaining the engagement state without causing slippage in the normal traveling state at that time is set and the engagement pressure is transient. It is in a state of being stably maintained, not at the normal pressure. This is because, as will be described later, control is performed to reduce the engagement pressure from the engaged state to the state just before slippage or to the engagement pressure at the start of slippage.

The state in which this control precondition is satisfied is shown in FIG.
Is shown before the time t1. That is, the engine speed Ne and the turbine speed Nt are stable at a substantially constant level, and the hydraulic pressure of the lockup clutch (L / U clutch) is constantly high enough to prevent slippage. Is constantly high enough to prevent belt slippage. This is the control content in a normal traveling state, and is shown as "phase0" in FIG. The "phase" is a symbol attached to the control content to be executed, and also functions to indicate the destination of the control step in the flowcharts of FIGS.

When the affirmative determination is made in step S101, it is determined whether the control start condition is satisfied (step S102). If it is determined that the control start condition is satisfied, that is, if the determination in step S102 is affirmative, "phase" is set to "1" (step S103). If the control start condition is already satisfied, a negative determination is made in step S102, and in that case, step S103 is skipped and step S103 is skipped.
Proceed to 104.

The control for causing the lockup clutch 11 to act as a so-called torque fuse is performed by the drive torque (or positive torque) input from the engine 4 and the drive wheels 26.
This is possible when the negative torque applied from the side is stable, so control is performed under the condition of a steady state.
This is the control start condition. The steady state is the accelerator opening (the amount of depression of an accelerator pedal (not shown)) or the torque on the output side of the continuously variable transmission 1 (for example, the driven pulley 2).
That is, the change in the shaft torque (0) within a predetermined time is within a predetermined range. Then, the predetermined range can be a range corresponding to the vehicle speed.

Next, in step S104, it is determined whether or not the control end condition is satisfied. This control end condition is that any one of the above-mentioned control start conditions is no longer satisfied, and for example, the running state of the vehicle is no longer a steady state or the lockup clutch 11 is in an engaged state. It's gone.

If a negative determination is made in step S104 because the control termination condition is not satisfied, "ph
It is determined whether "ase" is set to "1" (step S105). If the control start condition is satisfied as described above, the "phase" is set to "1", so that the affirmative determination is made in step S105. As a result, the engagement pressure (hydraulic pressure) of the lockup clutch 11 is set to the first predetermined hydraulic pressure PLU1 (step S10).
6). This is time t1 in FIG.

This control is a control for reducing the engagement pressure in advance in order to improve the responsiveness of the control for causing the slip-up of the lockup clutch 11, and the reduction rate of the engagement pressure is not particularly limited. That is, it is controlled so as to immediately drop. In other words, it is controlled so that the gradient of decrease in the engagement pressure is maximized.

The first predetermined hydraulic pressure PLU1 is an engagement pressure at which slippage does not occur even when the characteristic variation of the lockup clutch 11 is taken into consideration. The pressure can be a hydraulic pressure set in consideration of the coefficient of friction μ obtained based on the input torque to the lockup clutch 11 and the variation in mechanical characteristics, or is set as a target in the continuously variable transmission mechanism 1. It is possible to obtain the input torque of the continuously variable transmission 1 from the clamping pressure and use the hydraulic pressure calculated based on the input torque.

Then, it is judged whether or not a predetermined time has passed (step S107). This predetermined time is the time required from the output of the command signal for lowering the engagement pressure to the first predetermined oil pressure PLU1 until the engagement pressure stabilizes at the first predetermined oil pressure PLU1, and is a predetermined constant value or These are map values set according to the state of the vehicle. In FIG. 7, t1
It is the time from time t2 to time t2.

If the determination in step S107 is affirmative, this means that the control of "phase1" has ended, so "phase" is set to "2" (step S10).
8). This is time t2 in FIG. Then, it is determined whether the lockup clutch 11 slips (step S109). If the determination in step S107 is negative because the above predetermined time has not elapsed, step S108 is skipped and step S108 is skipped.
Go to 109.

This step S109 is executed for the purpose of confirming the state of the lockup clutch 11. That is, if unintentional (or unanticipated) slippage occurs in the lockup clutch 11 during the control process for setting a predetermined margin for the transmission torque of the lockup clutch 11, the control cannot be executed normally.
The slippage of the lockup clutch 11 is detected or determined by comparing the input side rotation speed (for example, engine rotation speed Ne) of the lockup clutch 11 and the output side rotation speed (for example, turbine rotation speed Nt). You can do it. More specifically, by the fact that the difference between these rotational speeds becomes larger than a predetermined threshold value,
It is possible to detect that the lockup clutch 11 has slipped.

If the control proceeds as expected, the lock-up clutch 11 will not slip, so that a negative determination is made in step S109. On the other hand, if unintended slippage occurs in the lockup clutch 11 for some reason, a positive determination is made in step S109. In that case, "phase" is set to "4" and the flag F0 is set to "ON" (step S11).
0). Then, it progresses to step S112. If the lock-up clutch 11 does not slip and a negative determination is made in step S109, step S109 is performed.
Skip 110 and proceed to step S112.

In step S112, it is determined whether or not "phase" is set to "2". As described above, when the control for reducing the engagement pressure of the lockup clutch 11 to the first predetermined hydraulic pressure PLU1 is executed, "phase" is set to "2". That is,
Since the above predetermined time has elapsed, step S10
Since the "phase" is set to "2" in 8 and the lockup clutch 11 is not unintentionally slipped, the above step S110 is skipped and step S11 is skipped.
Since it has advanced to 2, "phase" is set to "2". Therefore, a positive determination is made in step S112. In that case, the engagement pressure (hydraulic pressure) of the lockup clutch 11 is reduced toward the second predetermined hydraulic pressure PLU2 at a predetermined reduction rate (first sweep gradient) DLPLU1 (step S113). This is the control from time t2 to time t3 in FIG.

Although the first sweep gradient DLPLU1 is smaller than the rate of reduction when reducing to the first predetermined hydraulic pressure PLU1, the engagement pressure of the lockup clutch 11 is to some extent.
It is a rate of reduction set to reduce quickly. That is, similarly to setting the first predetermined hydraulic pressure PLU1, when the lockup clutch 11 is rapidly reduced to an engagement pressure at which slippage occurs, the lockup clutch 11 slips excessively due to undershoot, or the lockup clutch 11 locks up. The clutch 11 is released. To avoid this, if the engagement pressure is gradually reduced from the stable engagement state, the responsiveness deteriorates. Therefore, the engagement pressure is first reduced stepwise, and then the engagement pressure is reduced with a somewhat large gradient.

Next, it is determined whether or not the engagement pressure has reached the second predetermined hydraulic pressure PLU2 (step S114). This judgment can be made based on the lapse of a predetermined time, or based on the detection value of a hydraulic sensor (not shown).

The second predetermined hydraulic pressure PLU2 is a hydraulic pressure that is higher than the engagement pressure at which the transmission torque margin of the lockup clutch 11 is zero by a predetermined value α, and is a pressure at which the lockup clutch 11 does not slip. is there. As an example, the lockup clutch 11 is released from the released state (OFF) to the engaged state (O) during normal traveling such as the “phase 0” state.
This is the hydraulic pressure set when switching to N).

This is because, as the hydraulic pressure, the hydraulic pressure corresponding to the inertia torque of the engine 4 is added to the margin transmission torque, and the added amount can be set to the predetermined value α. Alternatively, the second predetermined hydraulic pressure PLU2 calculates the difference between the lockup hydraulic pressure when switching the lockup clutch 11 from the OFF state to the ON state and the required engagement hydraulic pressure obtained based on the input torque at that time from the current input torque. It is possible to obtain a corrected hydraulic pressure by adding it to the required required hydraulic pressure.

When the engagement pressure of the lockup clutch 11 reaches the second predetermined hydraulic pressure PLU2, step S1
If the determination in step 14 is affirmative, "phase" is set to "3" to proceed to the next control (step S11).
5). Then, it is determined whether or not the input torque to the lockup clutch 11 at that time is within a region where a learning value described later is obtained (step S11).
6). If the engagement pressure has not reached the second predetermined pressure PLU2 and thus the determination in step S114 is negative, step S115 is skipped in order to prevent the control from proceeding to the next step. Proceed to S116.

The control described here is for controlling the engagement pressure of the lock-up clutch 11 to a hydraulic pressure at which a predetermined margin is provided for the transmission torque. Therefore, first, the margin is set to zero. Although it is necessary to make a determination, the engagement pressure corresponding to the state in which the margin is zero differs depending on the input torque to the lockup clutch 11. Therefore, when the engagement pressure that gives a predetermined margin for the transmission torque is obtained, the engagement pressure is learned by storing the engagement pressure in correspondence with the input torque at that time. The learning is as described later. Therefore, if it is already obtained from the learned value, unnecessary control can be omitted by using it, so whether the input torque at that time is within the torque region where the learned value is obtained or not. It was decided to decide whether or not.

Therefore, if the input torque at that time is in the torque region where the learning value is obtained and the determination in step S116 is affirmative, in order to proceed to the control corresponding to that, "phase Is set to "6" (step S117), and the process proceeds to step S118. It should be noted that the input torque at that time is not within the torque region where the learning value is obtained.
If the determination is negative in 16, it is not possible to proceed to the control using the learning value, and thus step S116 is skipped and the process proceeds to step S118.

This step S118 and the subsequent step S119 are the same control steps as the above-mentioned step S109 and the following step S110. That is, since the engagement pressure of the lockup clutch 11 may be reduced and the input torque may change in the process of reaching the above step S116 or step S117, it is determined whether the lockup clutch 11 slips. It is determined (step S118).

If the lockup clutch 11 slips and the answer in step S118 is affirmative, the slip is unintentional (or unexpected), and the slip is unintentional. "Phase" is set to "4" and the flag F0 is set to "ON" to proceed to the control corresponding to (step S11).
9). Then, it progresses to step S120. If the lock-up clutch 11 does not slip and a negative determination is made in step S118, step S118 is performed.
Skip 119 and proceed to step S120.

In step S120, it is determined whether or not "phase" is set to "3". As described above, when the control for reducing the engagement pressure of the lockup clutch 11 to the second predetermined hydraulic pressure PLU2 is executed, "phase" is set to "3". In that state, if the input torque is in the region where the learning value is not obtained, rewriting of "phase" in step S117 is not performed, and if unintentional slip does not occur, "phase" in step S119 is executed. Since "rewriting" is not performed, "phase" is "3", and therefore a positive determination is made in step S120. In that case, the engagement pressure (hydraulic pressure) of the lockup clutch 11
Is decreased at a predetermined decrease rate (second sweep gradient) DLPLU2 (step S121). This is the control from time t3 to time t4 in FIG.

The second sweep slope DLPLU2 has a lower rate of decrease than the first sweep slope DLPLU1 described above. That is, since the engagement pressure of the lock-up clutch 11 is reduced, slippage is likely to occur in the lock-up clutch 11 due to a slight change in hydraulic pressure, and therefore the engagement pressure is reduced in order to prevent the slippage from becoming excessive. The rate was set small. In other words, this is to avoid undershoot of the hydraulic pressure or excessive slippage or release of the lockup clutch 11 due to the undershoot.

Next, it is judged whether or not the input torque to the lockup clutch 11 at that time is within the range where the learning value described later is obtained (step S).
122). This step S122 is the same determination step as step S116 described above, and is to use the learning value for the engagement pressure if it has already been obtained.

Therefore, if the determination in step S122 is affirmative, "phase" is set to "6" in order to proceed to the control using the learning value (step S1).
23). Then, the process proceeds to step S124. On the contrary, if the input torque to the lockup clutch 11 is in the region where the learning value is not obtained, “phas
The process proceeds to step S124 without rewriting "e".

The hydraulic pressure reduction control in the above step S120 is the final stage control in the hydraulic pressure reduction control for causing the lockup clutch 11 in the engaged state to slip. Therefore, in step S124, the lockup clutch is controlled. It is determined whether or not slippage has occurred at 11. This determination is made by comparing the input side rotation speed with the output side rotation speed, or by comparing the difference in the rotation speed with a predetermined threshold value, as in steps S109 and S118 described above. be able to. More specifically, the slip of the lockup clutch 11 detected in step S124 is a minute slip that is caused by gradually decreasing the engagement pressure, and specifically,
The state in which the rotation speed difference between the rotation speed on the input side and the rotation speed on the output side of the lockup clutch 11 is equal to or greater than a predetermined rotation speed (for example, 50 rpm) continues for a predetermined time (for example, 50 ms). Thus, slippage of the lockup clutch 11 can be detected.

If a positive determination is made in step S124 due to slight slippage of the lockup clutch 11, "phase" is set to "4" to proceed to the next control (step S125). . Then, the process proceeds to step S126. On the contrary, since the lock-up clutch 11 has not slipped yet, step S
If the determination in step 124 is negative, the process cannot proceed to the next control, so that "phase" is not rewritten (step S12).
(Skip 5) and proceed to step S126.

In step S126, it is determined whether "phase" is set to "4". The engagement pressure of the lockup clutch 11 is set to the above-mentioned second sweep gradient DL.
Lock-up clutch 1 by reducing with PLU2
If slippage occurs as 1 assumes, step S12
Since "phase" is set to "4" in step 5, step S
Affirmative determination is made at 126.

In this state, the engagement pressure of the lockup clutch 11 is slightly lower than the engagement pressure at which the margin of the transmission torque is zero. Therefore, after the slip of the lockup clutch 11 is detected, the engagement hydraulic pressure is increased at the third sweep gradient (the hydraulic pressure increase rate) DLPLU3 (step S127). This is a control for re-engaging the lock-up clutch 11 from the slight slip state, and in order to re-engage the lock-up clutch 11 when the transmission torque margin is zero, the third sweep gradient DLPLU3 is set to the minimum gradient. To be done. That is, the hydraulic pressure for engaging the lockup clutch 11 is increased very little. This is the control from time t4 to time t5 in FIG.

Next, it is determined whether or not the engagement determination of the lockup clutch 11 is established, that is, whether or not the lockup clutch 11 is engaged (step S12).
8). If the margin of the transmission torque is zero, there is no difference between the input rotation speed and the output rotation speed of the lockup clutch 11. This is the same as the case where the margin of the transmission torque is excessive. It is not always possible to accurately detect re-engagement when the margin is zero. Therefore, while the engagement pressure is being increased by the third sweep gradient DLPLU3, the rotation speed difference between the input rotation speed and the output rotation speed of the lockup clutch 11 is a predetermined value (for example, 50 rp).
When the state smaller than m) continues for a predetermined time (for example, 100 ms), the determination of re-engagement of the lockup clutch 11 is established. This is time t5 in FIG.

Since the control of "phase 4" is completed in this way, "phase" is set to "5" in order to proceed to the next control (step S129). Following this, it is judged whether or not the above-mentioned flag F0 is "ON" (step S130). As described above, the flag F0 is set to "ON" when unintentional (or unanticipated) slippage of the lockup clutch 11 is detected in the process of controlling the engagement pressure (steps S110 and S1).
From step 19), it is determined in step S130 whether or not the lockup clutch 11 has been reengaged after an unintended slip.

Therefore, if the determination in step S130 is affirmative, the unintentional lockup clutch 1
In order to perform the control of "phase3" corresponding to the slip of 1, "phase" is set to "3", and the flag F0 is set.
Is set to "OFF" (step S131). Then, it progresses to step S132. In addition, when the lock-up clutch 11 is re-engaged after the intended slip and a negative determination is made in step S130, step S131 is skipped and the process proceeds to step S132. That is, "phase" is maintained at "5".

In step S132, it is determined whether or not "phase" is set to "5". As described above, the lockup clutch 11 is slightly slipped by slowly reducing the engagement pressure, and then the lockup clutch 1 is increased by increasing the engagement pressure at the minimum gradient.
If the determination of the re-engagement of 1 is established, since "phase" is set to "5", the determination is affirmative in step S132. That is, when the change in the behavior of the lockup clutch 11 due to the change in the engagement pressure changes as expected, the control proceeds to "phase 5".

If a positive determination is made in step S132, the engagement hydraulic pressure of the lockup clutch 11 is "phase".
The hydraulic pressure at the end time of "4" (time t5 in FIG. 7), that is, the hydraulic pressure at the time when it is determined to reengage the lockup clutch 11 is set (step S133). And
It is determined whether a predetermined time has passed (step S1).
34). This is from time t5 to time t6 in FIG. 7, and is a predetermined time for stabilizing the engagement hydraulic pressure of the lockup clutch 11 to the hydraulic pressure at time t5.

When the predetermined time has elapsed, step S
If the determination in step 134 is affirmative, "phase" is set to "6" to proceed to the next control (step S135). Then, the hydraulic pressure learning value is stored (step S136). Then, the process proceeds to step S137.

That is, the first predetermined hydraulic pressure PLU1 set by stepwise decreasing from the hydraulic pressure that maintains the lock-up clutch 11 in the engaged state, and the third predetermined hydraulic pressure when the lock-up clutch 11 is re-engaged. Pressure difference DP with hydraulic pressure PLU3
LU1 is stored as the hydraulic pressure (engagement pressure) when the transmission torque margin is zero. In other words, the learning value DPLU1 that gives the engagement pressure of the lockup clutch 11 in which the margin of the transmission torque is zero is stored.

The learning value DPLU1 is obtained by dividing the input torque into a plurality of predetermined regions, storing each region, and holding it as a map. Therefore, the above-mentioned step S116
The determination in step S122 is a determination based on the presence or absence of the learning value thus obtained.

If the determination in step S134 is negative because the predetermined time has not elapsed, steps S135 and S136 are skipped and the process proceeds to step S137. Therefore, in this case, "phase
Is not rewritten and is maintained at "5".

Further, it is determined whether or not the unintended slip of the lockup clutch 11 has occurred at this time. This is the control of step S137. this is,
This is a determination step similar to step S109 and step S118 described above, and therefore this step S137
If the answer is YES, the "phase" is set to "4" and the flag F0 is set to "ON" to proceed to the control corresponding to the slip (step S13).
8). Then, it progresses to step S139. If the lock-up clutch 11 does not slip and a negative determination is made in step S137, step S137 is performed.
Skip 138 and proceed to step S139.

In step S139, it is determined whether or not "phase" is set to "6". As described above, when the learned value is stored in a state where the engagement hydraulic pressure of the lockup clutch 11 is maintained at the hydraulic pressure PLU3 with zero transmission torque margin, and the lockup clutch 11 does not have an unintended slippage. "Phase" is "6"
Since it is set to, a positive determination is made in step S139.

In this case, the lockup clutch 11
The engagement hydraulic pressure of is set to the hydraulic pressure calculated based on the input torque and the hydraulic pressure that is learning-corrected by the learning value (step S140). Specifically, the above "phas
The first predetermined hydraulic pressure PLU1 set by stepping down in "e1" is calculated based on the current input torque, and this is set as the hydraulic pressure based on the input torque of the lockup clutch 11. Next, the learning value DPLU1 is subtracted from the hydraulic pressure PLU1 to obtain a hydraulic pressure with no margin in the transmission torque of the lockup clutch 11 (hydraulic pressure with zero margin). The hydraulic pressure of the lock-up clutch 11 is set by adding the predetermined hydraulic pressure DPLU2, which is determined in advance, to the hydraulic pressure for which the transfer torque margin is zero. This is the control at time t6 in FIG. The surplus oil pressure DPLU2 is not likely to cause slippage in the lockup clutch 11 in a steady or quasi-steady running state, and when a torque exceeding the torque that acts in the steady or quasi-steady running state is applied. Is a hydraulic pressure that causes the lock-up clutch 11 to slip.

With the engagement hydraulic pressure of the lockup clutch 11 set as described above, the lockup clutch 1
Since the input torque for 1 may change, whether or not the input torque has entered the unlearned region, that is, whether or not the learned value has not yet been obtained, following step S140 described above. Is determined (step S141). The situation at that time is that the lock-up clutch 11 is engaged without slippage, and the engagement pressure is hydraulic pressure with a small margin of transmission torque.

Therefore, the control of "phase 2" is executed again in order to generate a slight slip and perform learning again. That is, "phase" is set to "2" (step S142). Then, the process proceeds to step S143. When the input torque is in the region where the learning value is obtained and the determination in step S141 is affirmative, the process immediately proceeds to step S143 without changing "phase".

In step S143, it is determined whether the lockup clutch 11 has slipped. That is, when the vehicle is traveling in the steady state or the quasi-steady state, the change in the driving torque or the negative torque on the output side is small, and the lock-up clutch 11 does not slip due to the above-mentioned margin of the transmission torque. When a torque exceeding 10 is applied to the lockup clutch 11, slippage occurs in the lockup clutch 11. Therefore, when the slip of the lockup clutch 11 is detected and affirmatively determined in step S143, it means that the running state has changed to an unsteady state.

Therefore, if the determination in step S143 is affirmative, "phase" is set to "0" (step S144). Then, it proceeds to step S145. When the slip of the lockup clutch 11 is not detected and the result of the determination in step S143 is negative, "phase" is not changed, that is, step S144 is skipped and the process proceeds to step S145.

The control content of "phase0" is t1 shown in FIG.
The control content is before the time point or after the time point t7, and the normal control is performed on the engagement pressure of the lockup clutch 11 and the clamping pressure of the continuously variable transmission mechanism 1. Specifically, the engagement pressure of the lock-up clutch 11 and the clamping pressure of the continuously variable transmission mechanism 1 are increased, and the lock-up clutch 11 and the continuously variable transmission mechanism may be changed depending on a change in engine torque or a negative torque on the output side. 1 is in a state where no slippage occurs.

Then, in step S145, "phase
Is set to "6". As described above, “phase6” is a state in which the engagement hydraulic pressure that gives a predetermined margin to the transmission torque of the lockup clutch 11 is stably set, and this is from t6 to t7 in FIG. It is in a state.

Therefore, when the "phase" is set to "6" and the determination in step S145 is affirmative, the belt clamping pressure of the continuously variable transmission mechanism 1 gives the transmission torque a predetermined margin. The pressure is reduced (step S146). As shown in FIG. 7, the clamping pressure is a pressure obtained by adding a predetermined value to a pressure at which the margin of transmission torque is zero. It should be noted that the margin of the transmission torque in the continuously variable transmission 1 set in this way is determined by the lockup clutch 1
When the drive torque and the negative torque are larger than the margin of the transmission torque in No. 1, the lockup clutch 11 precedes the continuously variable transmission mechanism 1 and slips.

Therefore, according to the control device of the present invention which performs the above control, the engagement pressure at which the margin of the transmission torque of the lock-up clutch 11 becomes zero is obtained, and the pressure is given a certain margin for the transmission torque. Since the margin pressure is applied to set the engagement pressure of the lockup clutch 11, the engagement pressure of the lockup clutch 11 is not controlled to decrease thereafter until slippage occurs. Therefore, it is possible to avoid situations in which the lock-up clutch 11 is repeatedly slipped, and the power transmission efficiency of the drive system is reduced accordingly, which deteriorates fuel consumption.

Further, since the state in which the margin of the transmission torque of the lockup clutch 11 is zero is detected or determined and the margin pressure is applied to this state, the engagement pressure of the lockup clutch 11 does not become excessive. The margin of the transmission torque of the lock-up clutch 11 can be reliably set smaller than the margin of the continuously variable transmission 1. Further, since the engagement hydraulic pressure at which the margin of the transmission torque becomes zero is obtained by the learning control, even if the lockup clutch 11 and its hydraulic control device have individual differences or changes with time, the transmission is performed without being affected by them. It is possible to stably set the engagement pressure at which the torque has a predetermined margin.

Furthermore, when the engine torque or the negative torque on the driving wheel side changes abruptly in a steady or quasi-steady running state, the lockup clutch 11 precedes the continuously variable transmission mechanism 1 and slips. As it occurs, the continuously variable transmission mechanism 1
It is possible to surely prevent slippage from occurring. Then, while preventing such a slip of the continuously variable transmission mechanism 1,
Since the clamping force can be made as low as possible, the power transmission efficiency in the continuously variable transmission mechanism 1 can be improved and the fuel consumption can be improved.

The series of controls described above is the control in the state where the input torque for which the learning value is not obtained is acting on the lockup clutch 11. Therefore, until the slight slippage occurs in the lockup clutch 11, the engagement pressure is reduced in a plurality of steps, and thereafter, the engagement pressure is increased to reengage the lockup clutch 11, thereby performing the various controls described above. Ran On the other hand, when the learning value has already been obtained, the control is performed as follows.

That is, if the input torque is within the region where the learning value is obtained, the affirmative judgment is made in step S116 shown in FIG. 2, and "phase" is set to "6" (step S117). This determination is executed while the engagement pressure is reduced stepwise to the first predetermined hydraulic pressure PLU1 in "phase1" and then the engagement pressure is reduced in the first sweep gradient DLPLU1 in "phase2".

When "phase" is set to "6" in the above step S117, a negative determination is made in any of step S120, step S126, and step S132 for determining "phase". Therefore, the process immediately proceeds to step S139, where a positive determination is made. The control after step S139 is as described above.

Therefore, when the learning value has already been obtained, the learning value DPLU1 is immediately executed after the control of "phase1" for setting the first predetermined hydraulic pressure PLU1 based on the input torque is executed.
The engagement pressure corrected in step S14 is reduced (step S14).
0). In that case, the engagement hydraulic pressure to be set is close to the engagement hydraulic pressure at which the lock-up clutch 11 slips, so that the lock-up clutch 11 due to undershoot of the hydraulic pressure is used.
In order to prevent the disengagement or the excessive slippage, the smoothing control is performed and the engagement oil pressure reduction control is executed.

When the learning value is obtained in this way, the engaging pressure of the lock-up clutch 11 can be controlled to be reduced by using the learning value. Therefore, the above-mentioned "phase 2" to "phase 5" control is performed. Omitting it enables quick control.

Further, the input torque changes in the above-described series of control processes, and as a result, the input torque enters from a region where the learning value is obtained to a region where the learning value is not obtained, and vice versa. In some cases, the area where the learning value is obtained may enter from the area where the value is not obtained. In the former case, it is not possible to control using the learning value, so it is necessary to perform learning, and in the latter case, the control for obtaining the learning value is unnecessary and the control using the learning value is not necessary. It will be possible.

More specifically, when the input torque of the lockup clutch 11 changes from the torque region where the learning value is obtained to the torque region where the learning value is not obtained, the above-mentioned step S116 is negatively answered. Judged,
Alternatively, a negative determination is made in step S122. Therefore, if the input torque changes to the torque region where the learning value is not obtained before setting the engagement hydraulic pressure with a certain margin hydraulic pressure added to the engagement hydraulic pressure with zero transmission torque margin, "phase1" Or, a series of control of "phase 6" is executed in the order described above.

On the other hand, the lockup clutch 11
If the input torque changes to the torque region where the learning value has not been obtained after setting the engagement hydraulic pressure that causes a predetermined margin in the transmission torque of, the affirmative determination is made in step S141. Along with that, "phase" is set to "2", so that "phase2" control is executed. This is shown in Figure 2.
The control is performed when the determination in step S112 is positive, and the engagement pressure is reduced by the first sweep gradient DLPLU1 so that a slight slip occurs in the lockup clutch 11, and the second predetermined hydraulic pressure PLU2 is reached. After that, the engagement pressure is reduced by the second sweep gradient DLPU2, and as a result, after a slight slip of the lockup clutch 11 is detected, the pressure is increased by the third sweep gradient DLPLU3, and after the re-engagement is detected,
The engagement pressure is set by adding a predetermined hydraulic pressure to the hydraulic pressure at that time. This is the control after step S112 of the example control described above.

On the other hand, as an example of the case where the input torque changes from the torque area where the learning value is not obtained to the torque area where the learning value is obtained, after stepping down to the first predetermined hydraulic pressure PLU1 (“phase1”) When the input torque of the lockup clutch 11 enters the torque region where the learned value is obtained after the control of (1) is completed), a positive determination is made in step S116 shown in FIG. The control in this case is
Similar to the case where the above learning value is obtained, the process immediately proceeds to step S139, and the lockup clutch 1
The engagement hydraulic pressure is set based on a learning value that gives a predetermined margin to the transmission torque of 1 (step S140).

If the input torque changes to the torque region where the learning value is obtained after the engagement pressure is reduced to the second predetermined hydraulic pressure PLU2, a positive determination is made in step S122 shown in FIG. As a result, since "phase" is set to "6", the process immediately proceeds to step S139, and the engagement pressure is set based on the learned value so that the transmission torque has a predetermined margin.

After the slight slip of the lockup clutch 11 is detected, each control is executed in the order of the series of controls described above. That is, there is no difference from the series of controls described above.

As described above, in the above control device according to the present invention, when the input torque changes between the so-called learned region and the unlearned region, the subsequent control is performed according to the progress state of the engagement pressure control. Is selected. Therefore, the above-described learning of the engagement pressure can be performed, and unnecessary control that is unnecessary can be omitted.

By the way, in the above series of processes for controlling the engagement hydraulic pressure of the lock-up clutch 11 so that the transmission torque has a predetermined margin, it is caused by a decrease in the engagement hydraulic pressure or a change in the input torque. As a result, the lockup clutch 11 may slip. This is, for example, step S1
09, step S118, step S124, step S137, and step S143.

Therefore, if the lockup clutch 11 slips in the process of lowering the engagement pressure to the second predetermined hydraulic pressure PLU2 or when the lockup clutch 11 is at the second predetermined hydraulic pressure PLU2, affirmative determination is made in step S109 or step S118. To be judged. In any of these cases, "ph
"ase" is set to "4" and the flag F0 is "ON".
Control (step S110, step S11)
9). As a result, the routine proceeds to step S126 shown in FIG. 4, and the control thereafter is executed in order, and the engagement pressure is slowly increased.

As a result, the lock-up clutch 11 that has once slipped is reengaged (step S128).
In this case, since the flag F0 is set to "ON", "phase" is set to "3" (step S13).
0, step S131), so the control is "phase3"
Return to. Therefore, the learning is not performed because step S135 shown in FIG. 5 is not reached. This corresponds to the prohibition of learning.

In this way, if the lockup clutch 11 slips unintentionally during the control process, the lockup clutch 11 is returned to the engaged state, and the engagement pressure is reduced again and the slight slippage is detected. The above-described series of controls such as boosting is executed. At the same time, learning of the engagement pressure at which the margin of the transmission torque becomes zero, or learning of the engagement pressure at which a predetermined margin of the transmission torque including the margin is learned is prohibited.

If the lockup clutch 11 slips while the second predetermined hydraulic pressure PLU2 is being reduced, a positive determination is made in step S124 shown in FIG. Since this is the intended slip, "phase" is set to "4" (step S125), and then the series of controls described above is executed, that is, there is no difference from the series of controls described above.

Furthermore, if unintended slippage occurs after the lockup clutch 11 is reengaged, a positive determination is made in step S137. In this case, "phase
Is set to "4", and the flag F0 is controlled to "ON" (step S138), so that the process proceeds to step S126 shown in FIG.
The engagement pressure is slowly increased. This is similar to the example described above.

If slippage of the lockup clutch 11 occurs after setting the engagement pressure so as to give a predetermined margin to the transmission torque, an affirmative decision is made in step S143, and "phase" is set to "0". Set (Step S
144). That is, the control is terminated assuming that the running state of the vehicle has become an unsteady state. In this case, the process starts again from step S101.

As described above, in the above-described control, when the lock-up clutch 11 slips unintentionally, the control to be performed next is selected according to the control situation at that time. Inconveniences such as the clutch 11 slipping excessively or unnecessary control being repeated can be avoided.

When the negative determination is made in step S101 because the preconditions for control are not satisfied,
When the control termination condition is satisfied and the determination in step S104 is affirmative, "phase" is set to "0" (step S111). This is the same as step S144 shown in FIG. 6, and therefore, the engagement pressure of the lockup clutch 11 and the continuously variable transmission mechanism 1 are the same.
The clamping pressure of is controlled to a relatively high pressure set in a normal traveling state. Then, the process proceeds to step S145, but since "phase" is set to "0", a negative determination is made in step S145, and the control ends.

Further, in the flowcharts shown in FIGS. 1 to 6, the judgment step S10 for "phase" is executed.
5, S112, S120, S126, S132, S13
If the determination is negative in step 9, the procedure proceeds to the determination step for "phase" after the step in which the determination is made. If a negative determination is made in the final determination step S145 for "phase", as shown in FIG.
Through the routine shown in FIG.

Here, the relation between the above-mentioned specific example and the present invention will be briefly described. Steps S106, S113 and S1.
Each of the functional means of 21 corresponds to the engagement pressure reducing means of the present invention, the mechanical means of step S127 corresponds to the re-engagement means of the present invention, and the functional means of step S140 corresponds to
It corresponds to the engagement pressure setting means of the present invention. Also, the functional means of steps S133 and S136 correspond to the learning means of the present invention, and the functional means for performing the smoothing process to execute the control of the engagement pressure using the learned value in step S140 is the learning means of the present invention. It corresponds to the "means for reducing the engagement pressure by performing a smoothing process" of the invention.

Here, another embodiment of the present invention disclosed as the above specific example will be illustrated as follows.

In the invention described in claim 1,
Prior to setting the engagement pressure that produces a predetermined margin in the clutch transmission torque, the engagement pressure of the continuously variable transmission is maintained at a high pressure that does not cause slippage, and a predetermined margin is created in the clutch transmission torque. The control device may be provided with means for reducing the clamping pressure of the continuously variable transmission mechanism to a pressure at which a predetermined margin is provided in the transmission torque after the combined pressure is set. This corresponds to maintaining the belt clamping pressure high until time t6 shown in FIG.

In the invention described in claim 1,
If slippage occurs in the clutch when the clutch transmission torque is set to an engagement pressure that allows a certain margin,
The control device may be provided with means for increasing the engagement pressure at which the clutch does not slip and increasing the clamping pressure of the continuously variable transmission mechanism to the pressure at which no slip occurs. This corresponds to the control in step S144 described above.

In the invention described in claim 2,
The control device may be configured so that the engagement pressure that is first reduced and set is set to a hydraulic pressure that does not cause slippage in the clutch even when considering variations in clutch characteristics calculated from the input torque of the clutch. This is step S1
It corresponds to 06.

In the invention described in claim 2, the engagement pressure secondly set in the process of reducing the engagement pressure in a plurality of steps is set when the clutch is switched from off to on during normal traveling. The control device may be configured so as to obtain the engagement pressure.

In the invention described in claim 2, in the process of lowering the engagement pressure, after the first predetermined value is maintained for a predetermined time, the engagement pressure is decreased at a predetermined sweep gradient. It can be a device. This corresponds to the above-mentioned control of "phase 1" to "phase 3", and by doing so, the hydraulic response can be improved and the hydraulic undershoot can be avoided.

In the invention described in claim 1, the determination of the re-engagement of the clutch is made in a predetermined time when the difference between the rotation speed on the input side and the rotation speed on the output side is reduced to a predetermined value or less. The control device can be configured to perform the operation continuously. This corresponds to the control of step S128, and by doing so, it is possible to reliably detect or determine the state in which the margin of the transmission torque is zero.

In the invention described in claim 1, the engagement pressure that causes a predetermined margin in the transmission torque of the clutch is
The control device may be configured so as to have means for obtaining it based on the input torque of the clutch.

Alternatively, in the invention described in claim 1, there is provided a means for obtaining an engagement pressure for producing a predetermined margin in the transmission torque of the clutch, based on a hydraulic pressure when the clutch is re-engaged. It can be a controller.
In that case, a lower hydraulic pressure can be set by the hydraulic pressure corresponding to the inertia torque at the time of re-engagement.

In the invention described in claim 1, the control device may be constructed so that the control start condition is that the vehicle is traveling in a steady state. In that case, it can be configured to determine that the steady state is established when the accelerator opening is within a predetermined value continuously for a predetermined time. Further, it can be configured to determine that the output side torque of the continuously variable transmission mechanism, which is calculated from the input torque, is continuously within a predetermined value for a predetermined time and is in a steady state. This corresponds to step S102.

The steady running state of the vehicle may be determined by the reference acceleration of the vehicle being within a predetermined range or the road surface gradient being within a predetermined range. When the input torque is large due to the large road surface gradient, the control of the engagement pressure that gives a predetermined margin to the transmission torque is prohibited, and as a result, the slipping of the clutch can be more reliably prevented.

The present invention is not limited to the specific examples described above, and the clutch of the present invention is a so-called start clutch that is gradually engaged when the vehicle starts, in addition to the above lock-up clutch. Maybe,
In addition, the arrangement may be, as long as it is in series with the continuously variable transmission mechanism in the torque transmission direction, and thus may be at either the input side or the output side of the continuously variable transmission mechanism. Further, the continuously variable transmission mechanism is not limited to the belt type, but may be a toroidal type (traction type). Further, in the case of lowering the engagement pressure, the engagement pressure may be reduced in two steps other than in three steps as in the above-described specific example, and the point is that it may be divided into a plurality of steps.

[0131]

As described above, according to the first aspect of the present invention, when the transmission torque has a predetermined margin and the clutch is not slipped, the engagement pressure is reduced thereafter. Since it is not caused, slipping of the clutch does not occur repeatedly, and therefore inconveniences such as deterioration of power transmission efficiency and deterioration of clutch durability can be avoided.

Further, according to the second aspect of the invention, when the engagement pressure of the clutch in the engaged state is reduced, the rate of decrease of the engagement pressure after that is higher than the rate of decrease at the start of the decrease. Therefore, it is possible to improve the responsiveness of the control for lowering the engagement pressure that causes slippage in the clutch, avoid the so-called undershoot of the decrease in engagement pressure, and prevent the clutch from slipping excessively. The so-called release shock can be prevented or suppressed.

Further, according to the third aspect of the present invention, the engagement pressure set in the process of lowering the engagement pressure of the clutch so that the clutch slips is based on the input torque of the continuously variable transmission mechanism. Therefore, if the clamping pressure that determines the transmission torque of the continuously variable transmission mechanism is high for some reason, the clutch engagement pressure is set high accordingly, and as a result,
The desired engagement pressure reduction control can be rapidly advanced without causing slippage in the clutch in the process of reducing the engagement pressure.

Further, according to the invention of claim 4, in the process of lowering the engagement pressure so as to cause the clutch to slip, the coefficient set immediately before the final reduction control to reach the clutch slip is performed. Since the combined pressure is corrected based on the engagement pressure during normal engagement control that does not involve clutch lowering control, that engagement pressure can be brought closer to the clutch engagement pressure that is actually required. As a result, the engagement pressure can be rapidly reduced within the range where the clutch does not slip.

According to the fifth aspect of the invention, after the engagement pressure with which the transmission torque of the clutch has no margin is clarified,
Since the clutch is engaged with an engagement pressure obtained by adding a predetermined value for the margin to the engagement pressure, it is possible to optimize the margin in the transmission torque of the clutch.

Further, according to the invention of claim 6, the engagement pressure that gives a predetermined margin to the transmission torque of the clutch is obtained based on learning, so that the engagement pressure is different between individual clutches and changes with time. Is reflected in the actual state, and accordingly, the margin of the transmission torque of the clutch can be optimized.

Furthermore, according to the invention of claim 7, the engagement pressure of the clutch to be reduced and set is known as a learning value, and the engagement pressure of the engaged clutch can be obtained by the learning. When the value is decreased to a certain value, the value is gently decreased by the control that has been subjected to the smoothing process without being suddenly decreased, so that the situation such as the undershoot of the engagement pressure and the release of the clutch due to it can be avoided. .

Furthermore, according to the invention of claim 8,
In the process of lowering the engagement pressure of the engaged clutch to cause slippage, the process of increasing the engagement pressure of the slipped clutch, and the state of reengaging the clutch, the operating state of the drive system is When there is a change between the state where the learning value is obtained and the state where the learning value is not obtained, the next control content is determined based on the control state of the engagement pressure at that time, so the learning value is obtained. When the operating state changes, the learned value can be used to control the engagement pressure, and unnecessary control can be omitted to perform quick and easy control. On the contrary, when the driving state is changed so that the learning value is not obtained, the learning value can be obtained.

According to the ninth aspect of the invention, when the clutch slips during the process of controlling the clutch engagement pressure to an engagement pressure with a certain margin in the transmission torque, the clutch is re-engaged. Since the engagement pressure is increased so that the engagement is performed and the learning of the engagement pressure is prohibited, it is possible to avoid excessive slippage of the clutch and, at the same time, avoid erroneous learning of the engagement pressure.

[Brief description of drawings]

FIG. 1 is a diagram showing a part of a flow chart for explaining an example of control by a control device of the present invention.

FIG. 2 is a diagram showing a portion following FIG. 1 of a flowchart for explaining an example of control by the control device of the present invention.

FIG. 3 is a diagram showing a part following FIG. 2 of a flowchart for explaining an example of control by the control device of the present invention.

FIG. 4 is a diagram showing a part following FIG. 3 of a flowchart for explaining an example of control by the control device of the present invention.

FIG. 5 is a diagram showing a portion following FIG. 4 of a flowchart for explaining an example of control by the control device of the present invention.

FIG. 6 is a diagram showing a part following FIG. 5 of a flowchart for explaining an example of control by the control device of the present invention.

FIG. 7 shows changes in the rotation speeds of the input side and the output side of the lockup clutch when the control according to the present invention is executed,
6 is a time chart showing changes in the engagement hydraulic pressure of the lockup clutch and changes in the belt clamping pressure.

FIG. 8 is a diagram schematically showing a drive system including a continuously variable transmission mechanism according to the present invention.

[Explanation of symbols]

1 ... Continuously variable transmission mechanism, 3 ... Torque converter, 4 ... Engine (power source), 11 ... Lock-up clutch, 1
9 ... Drive pulley, 20 ... Followed pulley, 23 ... Belt, 26 ... Drive wheel, 31 ... Electronic control unit for transmission (CVT-ECU).

Continued front page    (72) Inventor Kunihiro Iwatsuki             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. (72) Inventor Yasuhiro Oshiumi             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. F-term (reference) 3J552 MA06 MA12 NA01 NB01 PA63                       QA18C RA02 SA56 TA11                       TB20 UA02 VA32Y VA34Y                       VA37Y VA42W VC01Z

Claims (9)

[Claims]
1. A continuously variable transmission mechanism and a clutch are connected in series with each other in a torque transmission direction, and a margin of transmission torque of the clutch until slippage occurs in the clutch is slipped by the continuously variable transmission mechanism. In a control system of a drive system including a continuously variable transmission mechanism that is set to be smaller than a margin of transmission torque of the continuously variable transmission until the occurrence of the above, the engagement pressure of the engaged clutch is changed until the clutch slips. Engagement pressure reducing means for reducing, reengagement means for increasing the engagement pressure to reengage the clutch after slippage of the clutch is detected, and engagement when the clutch is reengaged A continuously variable transmission, comprising: an engagement pressure setting means for setting a pressure obtained by adding a predetermined value that gives the margin to the transmission torque of the clutch as an engagement pressure of the clutch. Drive system controller including components.
2. The engagement pressure reduction means is configured to reduce the engagement pressure through a plurality of stages in which the reduction rate of the engagement pressure is different and the reduction rate decreases as the engagement pressure decreases. The control device for the drive system including the continuously variable transmission mechanism according to claim 1.
3. The continuously variable transmission obtained by the engagement pressure lowering means, based on a clamping pressure that sets a transmission torque of the continuously variable transmission mechanism, as an engagement pressure set before slippage of the clutch. The control system for a drive system including a continuously variable transmission mechanism according to claim 2, wherein the engagement pressure is set based on an input torque of the mechanism and at which the clutch does not slip.
4. The engagement pressure reducing means transmits torque that is actually input to the clutch as an engagement pressure set before the engagement pressure is reduced at the final stage so that slippage occurs in the clutch. The engagement pressure required to perform the correction is set based on the engagement pressure at the time of normal engagement control in which the reduction control by the engagement pressure reduction means is not performed. A control device for a drive system including the continuously variable transmission mechanism according to claim 2.
5. The engagement pressure setting means sets an engagement pressure when the clutch is re-engaged so that the transmission torque of the clutch has no margin, and the engagement pressure is set to the transmission torque. 2. The control device for a drive system including a continuously variable transmission mechanism according to claim 1, wherein a pressure to which the predetermined value that gives a predetermined margin is applied is set as an engagement pressure of the clutch.
6. A drive system including a continuously variable transmission mechanism according to claim 1, further comprising learning means for learning an engagement pressure at which a margin of transmission torque of the clutch reaches the predetermined value. Control device.
7. When the engagement pressure of the clutch is reduced to the engagement pressure based on the learning value obtained by the learning means, a smoothing control is performed to further reduce the engagement pressure. 7. A control device for a drive system including the continuously variable transmission mechanism according to claim 6.
8. The operation means, wherein the learning means is configured to learn the engagement pressure for each operation state, and the operation state in which the learning of the engagement pressure is completed and the operation in which the learning of the engagement pressure is not completed. When the operating state is changed between the state and the state, further comprising means for determining the control content of the engagement pressure to be performed next according to the control state of the engagement pressure at that time. 7. A control device for a drive system including the continuously variable transmission mechanism according to item 6.
9. The re-engagement means in a state in which the engagement pressure of the clutch is reduced by the engagement pressure reducing means or in a state of maintaining the engagement pressure at which the clutch is re-engaged. When slipping of the clutch is detected, it is configured to increase the engagement pressure for re-engaging the clutch, and further comprises means for prohibiting learning of the engagement pressure by the learning means. A control device for a drive system including the continuously variable transmission mechanism according to claim 6.
JP2002027417A 2002-02-04 2002-02-04 Drive system control device including continuously variable transmission mechanism Expired - Fee Related JP4126916B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2002027417A JP4126916B2 (en) 2002-02-04 2002-02-04 Drive system control device including continuously variable transmission mechanism

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
JP2002027417A JP4126916B2 (en) 2002-02-04 2002-02-04 Drive system control device including continuously variable transmission mechanism
US10/356,599 US6974009B2 (en) 2002-02-04 2003-02-03 Control apparatus for power train including continuously variable transmission
DE10304436A DE10304436A1 (en) 2002-02-04 2003-02-04 Control device for a drive train with a continuously variable transmission
FR0301249A FR2835484B1 (en) 2002-02-04 2003-02-04 Control apparatus for a motor powertrain comprising a continuously changing transmission transmission
US11/115,303 US7188717B2 (en) 2002-02-04 2005-04-27 Control apparatus for power train including continuously variable transmission

Publications (2)

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JP2003227562A true JP2003227562A (en) 2003-08-15
JP4126916B2 JP4126916B2 (en) 2008-07-30

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7678016B2 (en) 2006-02-06 2010-03-16 Fuji Jukogyo Kabushiki Kaisha Control apparatus for vehicle

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7678016B2 (en) 2006-02-06 2010-03-16 Fuji Jukogyo Kabushiki Kaisha Control apparatus for vehicle

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