JP4182972B2 - Drive system control device including continuously variable transmission mechanism - Google Patents

Description

  This invention is a continuously variable transmission in which a torque transmission member that mediates torque transmission such as a belt or a power roller is brought into direct or indirect contact with a rotating member such as a pulley or a disk, and the torque capacity changes according to the contact pressure. More particularly, the present invention relates to a control device for controlling the engagement pressure of clutches arranged in series with a continuously variable transmission mechanism.

  The continuously variable transmission mechanism is configured to change the gear ratio steplessly by continuously changing the contact position or torque transmission position between the pulley or disk and the member that mediates the transmission of torque, such as a belt or power roller. Has been. The torque is transmitted using a frictional force or a shearing force of traction oil. Therefore, the torque capacity (transmission torque) determined based on the contact pressure between the member transmitting torque and the pulley or the disk or the pressure sandwiching the member transmitting torque (that is, the clamping pressure) and the friction coefficient or the shearing force of the traction oil If the torque is applied beyond the above, slippage of the belt or power roller occurs.

  If the belt or the power roller slips excessively, the pulley and the disk are worn. As a result, the torque cannot be transmitted at the worn portion, and the function as the continuously variable transmission mechanism is not achieved. Therefore, in order to prevent slippage in the continuously variable transmission mechanism during travel of a vehicle equipped with the continuously variable transmission mechanism, it is conceivable to increase the pinching pressure and increase the torque capacity.

  However, if the clamping pressure is increased, the transmission efficiency of the power in the continuously variable transmission mechanism is reduced, and more power is consumed to drive the oil pump that generates the hydraulic pressure. To do. Therefore, it is preferable that the clamping pressure of the continuously variable transmission mechanism be as low as possible within a range where no slip occurs.

  In that case, if the engine output torque or the negative torque on the wheel side changes frequently or greatly, the torque acting on the continuously variable transmission mechanism cannot be predicted, so there is a margin of safety factor or torque capacity. The margin (excess amount of torque capacity with respect to the minimum or limit torque capacity at which slip does not occur in a steady state) must be increased and set to a somewhat high clamping pressure. On the other hand, in a steady or quasi-steady running state, the torque acting on the continuously variable transmission mechanism is stable, so that the clamping pressure can be reduced to a state just before the slip occurs.

  However, since an unexpected torque may be generated even in a steady or quasi-steady running state, it is necessary to prevent or avoid slipping of the continuously variable transmission mechanism even in that case. For this reason, for example, in the invention described in Patent Document 1, a clutch is arranged in series with the continuously variable transmission mechanism, and the engagement force margin of the clutch is set smaller than the clamping pressure margin in the continuously variable transmission mechanism. When the slippage of the clutch is not detected, the engagement force and the pinching pressure are decreased. On the contrary, when the slippage of the clutch is detected, both the engagement force and the pinching pressure are controlled to increase. . Here, the margin of engagement pressure or clamping pressure is an excess of the minimum or limit engagement pressure or clamping pressure that does not cause slippage in a 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 increases, the clutch is preferentially slid to limit the torque acting on the continuously variable transmission mechanism. This is control for avoiding slippage of the step transmission mechanism. In other words, the control is to cause the clutches arranged in series with the continuously variable transmission mechanism to function as a so-called torque fuse.
Japanese Patent Laid-Open No. 10-2930

  However, in the invention described in the above publication, when clutch slippage is not detected, the clutch engagement force and the pinching pressure of the continuously variable transmission mechanism are reduced, and as a result, clutch slippage is detected. Since the engagement force of the clutch and the pinching pressure of the continuously variable transmission mechanism are increased, the engagement force and the pinching force are repeatedly reduced and increased, and accordingly, the clutch slips repeatedly. For this reason, in the conventional control device, there is a possibility that the power transmission efficiency in the drive system is lowered, the fuel consumption is deteriorated, or the effect of improving the fuel consumption by adopting the continuously variable transmission mechanism is impaired.

  The present invention has been made by paying attention to the above technical problem, and can optimize the transmission torque margin of the clutches arranged in series with the continuously variable transmission mechanism, and can be transmitted by the continuously variable transmission mechanism. 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 a torque margin.

In order to achieve the above object, the invention of claim 1 is directed to reducing the engagement pressure of the clutch arranged in series with respect to the continuously variable transmission mechanism from the fully engaged state until slip occurs, The clutch transmission torque until slippage occurs in the clutch by obtaining an engagement pressure obtained by adding a predetermined margin pressure to the engagement pressure at which the clutch is re-engaged by increasing the engagement pressure. Is a drive system control device including a continuously variable transmission mechanism that sets a margin of transmission less than a margin of transmission torque of the continuously variable transmission mechanism until slippage occurs in the continuously variable transmission mechanism. and end detecting means for end condition of the control for engaging the clutch engagement pressure imparted with predetermined margin pressure engagement pressure is detected to be satisfied, earlier SL end condition in this end detecting means established for the clutch after the lower child is detected In the case where the slip is detected, in that it comprises said continuously variable transmission mechanism of engagement-pressure increase means for increasing the engagement pressure of the clutch so that the slip does not occur after increasing the torque capacity It is the control device characterized.

A second aspect of the present invention, and wherein said engagement-pressure increase means definitive to claim 1, wherein when the clutch is in a state slip is configured to increase gradually the engagement pressure at a predetermined gradient It is a control device.

Therefore, according to the first aspect of the present invention, the control end condition for setting the margin of transmission torque with respect to the torque causing slipping in the clutch to be smaller than the margin of transmission torque with respect to the torque causing slipping in the continuously variable transmission mechanism is set. was formed upright, the subsequent sliding of the clutch is detected, first, the torque capacity of the continuously variable transmission mechanism is increased, then, the torque capacity of the clutch is increased. That is, the termination condition is, for example, clutch slip due to disturbance torque, and when the torque capacity is increased to prevent or avoid the slip, the torque capacity of the continuously variable transmission mechanism is increased prior to that. As a result, when disturbance torque is input in the transient state, slippage of the clutch occurs and the torque acting on the continuously variable transmission mechanism is limited, so that slippage of the continuously variable transmission mechanism is reliably avoided or prevented. be able to.

Therefore, according to the invention of claim 2, when the engagement pressure is increased from the state where the clutch is slipping, the engagement pressure is gradually increased. For this reason, the change in the rotational speed caused by the increase in clutch engagement pressure and the stoppage of slipping is moderated, and shock can be suppressed or prevented.

  Next, the present invention will be described based on specific examples. First, a drive system including a continuously variable transmission mechanism that is a subject of the present invention will be described. The present invention can be directed to a drive system mounted on a vehicle, and the continuously variable transmission mechanism included in the drive system includes: A belt-type continuously variable transmission mechanism with a belt as a torque transmission member, and a toroidal type (traction-type) continuously variable transmission that uses a power roller as a torque transmission member and uses the shearing force of oil (traction oil) A transmission mechanism. FIG. 23 schematically shows an example of a vehicle drive system including the belt-type continuously variable transmission mechanism 1, and the continuously variable transmission mechanism 1 is connected to a power via a forward / reverse switching mechanism 2 and a torque converter 3. Connected to source 4.

  The power source 4 is the same as a power source mounted on a general vehicle, and is an internal combustion engine such as a gasoline engine, a diesel engine or a natural gas engine, an electric motor, or a combination of an internal combustion engine and an electric motor. A mechanism or the like can be employed. In the following description, the power source 4 is referred to as the engine 4.

  The torque converter 3 connected to the output shaft of the engine 4 has the same structure as that of a conventional torque converter used in general vehicles, and a pump impeller 6 is connected to a front cover 5 to which the output shaft of the engine 4 is connected. A turbine runner 7 that is integrated and faces the pump impeller 6 is disposed 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). The pump impeller 6 rotates to generate a fluid spiral flow. The spiral runner 7 The turbine runner 7 is rotated by applying torque to the turbine runner 7.

  In addition, a stator 8 that selectively changes the flow direction of the fluid fed from the turbine runner 7 and flows into the pump impeller 6 is disposed in the inner peripheral portion of the pump impeller 6 and the turbine runner 7. . The stator 8 is connected to a predetermined fixing portion 10 via a one-way clutch 9.

  The torque converter 3 includes a lockup clutch (L / U clutch) 11 corresponding to the clutch in the present invention. The lock-up clutch 11 is arranged in parallel with a substantial torque converter including the pump impeller 6, the turbine runner 7, and the stator 8, and is in a state facing the inner surface of the front cover 5. 7 and is pressed against the inner surface of the front cover 5 by hydraulic pressure, so that torque is directly transmitted from the front cover 5 as an input member to the turbine runner 7 as 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 that is employed when the rotational direction of the engine 4 is limited to one direction, and outputs the input torque as it is or reversely outputs it. It is configured. In the example shown in FIG. 23, a double pinion type planetary gear mechanism is employed as the forward / reverse switching mechanism 2.

  That is, the ring gear 13 is arranged concentrically with the sun gear 12, and the pinion gear 14 meshed with the sun gear 12 and the pinion gear 14 and another pinion gear 15 meshed with the ring gear 13 are arranged between the sun gear 12 and the ring gear 13. These pinion gears 14 and 15 are held by a carrier 16 so as to rotate and revolve freely. A forward clutch 17 that integrally connects the two rotating elements (specifically, the sun gear 12 and the carrier 16) is provided, and the direction of the torque that is output by selectively fixing the ring gear 13 A reverse brake 18 for reversing is provided.

  The continuously variable transmission mechanism 1 has the same configuration as a conventionally known belt-type continuously variable transmission mechanism, and each of a driving pulley 19 and a driven pulley 20 arranged in parallel to each other includes a fixed sheave, a hydraulic type The movable sheave is moved back and forth in the axial direction by the actuators 21 and 22. Therefore, the groove width of each pulley 19 and 20 is changed by moving the movable sheave in the axial direction, and accordingly, the winding radius of the belt 23 wound around each pulley 19 and 20 (the effective diameter of the pulleys 19 and 20). ) Changes continuously, and the gear ratio changes steplessly. The drive pulley 19 is connected to a carrier 16 that is an output element in the forward / reverse switching mechanism 2.

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

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

  Various sensors are provided to detect the operating state (running state) of a vehicle on which the continuously variable transmission mechanism 1 and the engine 4 are mounted. That is, the engine speed sensor 27 that detects the rotation speed of the engine 4 (the input rotation speed of the lockup clutch 11) and outputs a signal, and the rotation speed of the turbine runner 7 (the output rotation speed of the lockup clutch 11) are detected. Turbine rotational speed sensor 28 for outputting a signal, input rotational speed sensor 29 for detecting the rotational speed of drive pulley 19 and outputting the signal, and output rotational speed sensor 30 for detecting the rotational speed of driven pulley 20 and outputting the signal. Etc. are provided.

  Control of engagement / release of the forward clutch 17 and reverse brake 18, control of the clamping force of the belt 23, control of torque capacity including engagement / release of the lockup clutch 11, and gear ratio In order to perform this control, a transmission electronic control unit (CVT-ECU) 31 is provided. The electronic control device 31 is configured mainly by a microcomputer as an example, performs calculations according to a predetermined program based on input data and data stored in advance, and various states such as forward, reverse or neutral, Further, control such as setting of the required clamping pressure and setting of the gear ratio is executed. In addition, an engine electronic control unit (E-ECU) 32 for controlling the engine 4 is provided, and data is communicated between the electronic control units 31 and 32.

  A control device according to the present invention for a drive system including the continuously variable transmission mechanism 1 is configured to cause the lockup clutch 11 to function as a so-called torque fuse for the continuously variable transmission mechanism 1. Specifically, this is because the torque capacity of the continuously variable transmission mechanism 1 and the lock-up clutch are set so that slip does not occur due to the torque acting at that time in a steady running state or a quasi-steady running state where the torque changes little. 11 and a so-called margin of each torque capacity (transmission torque), that is, a margin torque capacity that is given to the minimum torque capacity in a range where slipping does not occur is considered as a continuously variable transmission mechanism 1. Is set to be smaller in the lock-up clutch 11 than in. This is because when the torque acting on the drive system increases (increases in the positive direction) or decreases (increases in the negative direction), the lockup clutch 11 is caused to slip prior to the continuously variable transmission mechanism 1 and continuously variable. This is control for preventing the transmission mechanism 1 from slipping.

  The control device according to the present invention executes control for causing this type of clutch to function as a so-called torque fuse for the continuously variable transmission mechanism 1 as follows. FIG. 1 to FIG. 6 are flowcharts showing examples of the control. FIG. 7 determines the rotation speed, the engagement pressure (hydraulic pressure) of the lockup clutch 11 and the transmission torque in the continuously variable transmission mechanism 1 when the control is executed. It is a time chart which shows the change of the belt clamping pressure.

  In the present invention, when setting the engagement pressure (hydraulic pressure) so as to give a margin to the transmission torque of the lockup clutch 11, first, the control is started because the lockup clutch 11 is stably on-controlled. This is a precondition for control. Therefore, as shown in FIG. 1, first, it is determined that the control precondition is satisfied (step S110).

  Here, “stable ON control” means that the engagement pressure is set to maintain the engagement state without causing slippage in the normal running state at that time, and the engagement pressure is a transient pressure. Instead, it is in a stable state. This is because, as will be described later, control is performed to reduce the engagement pressure from the engaged state to the state immediately before the slip occurs or to the engagement pressure at the start of the slip.

  The state in which this control precondition is satisfied is shown as a state before time t1 in FIG. That is, the engine rotational speed Ne and the turbine rotational speed Nt are substantially constant and stable, and the hydraulic pressure of the lockup clutch (L / U clutch) is constant at a high pressure that does not cause slippage. Is constant at such a high pressure that belt slip does not occur. This is a control content in a normal running state, and is shown as “phase 0” in FIG. The “phase” is a symbol attached to the control content to be executed, and functions in the flowcharts of FIGS. 1 to 6 to indicate the destination of the control step.

  If the determination in step S110 is affirmative, it is determined whether or not a control start condition is satisfied (step S120). If it is determined that the control start condition is satisfied, that is, if the determination in step S120 is affirmative, “phase” is set to “1” (step S130). If the control start condition has already been established, a negative determination is made in step S120. In this case, step S130 is skipped and the process proceeds to step S140.

  Control for causing the lockup clutch 11 to act as a so-called torque fuse is possible when the drive torque (or positive torque) input from the engine 4 or the negative torque applied from the drive wheel 26 side is stable, and is therefore in a steady state. Alternatively, control is performed under the condition of a quasi-steady state. This is the control start condition. The steady state or quasi-steady state is a predetermined change in the accelerator opening (the amount of depression of an unillustrated accelerator pedal) or the torque on the output side of the continuously variable transmission mechanism 1 (for example, the shaft torque of the driven pulley 20). It is within the range. And the predetermined range can be made into the range according to the vehicle speed.

  Next, in step S140, the current input torque region is stored, and the flag F2 is set to "OFF" and initialized. Here, the area of the input torque means that various types of control are controlled for each input torque, and the input torque is divided for that purpose. Therefore, when the region to which the input torque belongs changes, the operating state has changed.

  After storing the input torque region, it is determined whether or not a control end condition is satisfied (step S150). This control end condition is that any one of the above-described control start conditions is not satisfied. For example, the traveling state of the vehicle is not in a steady state or a quasi-steady state, or the lockup clutch 11 is For example, slipping occurs and the engagement state is lost.

  If a negative determination is made in step S150 because the control end condition is not satisfied, it is determined whether or not the input torque region has changed from the stored value (step S160). Since various types of control including learning of the engagement pressure of the lockup clutch 11 is performed for each input torque, when the input torque changes, it is necessary to perform control according to the control. Therefore, the determination in step S160 is performed. Therefore, if the determination in step S160 is affirmative, the flag F2 is set to "ON" (step S170).

  For example, when the engine 4 is an engine capable of lean combustion, the change of the input torque is caused by changing the air-fuel ratio, and the engine load is changed by turning on / off auxiliary equipment such as an air conditioning compressor. This is caused by switching ON / OFF of the auxiliary machinery. Therefore, the determination in step S160 may be changed to a step of determining whether or not the air-fuel ratio is changed and whether or not auxiliary equipment is switched ON / OFF.

  If the determination in step S160 is affirmative and the flag F2 is "ON", or if the determination in step S160 is negative, whether or not "phase" is set to "1"? Is determined (step S180). When the control start condition is satisfied as described above, “phase” is set to “1”, so that an affirmative determination is made in step S180. As a result, the engagement pressure (hydraulic pressure) of the lockup clutch 11 is set to the first predetermined oil pressure PLU1 (step S190). This is the time t1 in FIG.

  This control is a control that lowers the engagement pressure in advance in order to improve the responsiveness of the control that causes the lockup clutch 11 to slip, and does not particularly limit the rate of decrease of the engagement pressure, that is, immediately decreases. To be controlled. In other words, control is performed so that the gradient of decrease in the engagement pressure is maximized.

  The first predetermined hydraulic pressure PLU1 is an engagement pressure that does not cause slipping even when variations in characteristics of the lockup clutch 11 are taken into consideration. The pressure can be a hydraulic pressure set in consideration of the friction coefficient μ obtained based on the input torque to the lockup clutch 11 and the variation in characteristics of the mechanism, or can be a target in the continuously variable transmission mechanism 1. The input torque of the continuously variable transmission mechanism 1 is obtained from the clamping pressure, and the hydraulic pressure calculated based on the input torque can be obtained.

  Next, it is determined whether or not a predetermined time has elapsed (step S200). This predetermined time is the time required from the output of the command signal for reducing the engagement pressure to the first predetermined hydraulic pressure PLU1 until the engagement pressure is stabilized at the first predetermined hydraulic pressure PLU1, and is a predetermined constant value or This is a map value set according to the state of the vehicle. In FIG. 7, the time is from the time t1 to the time t2.

  If the determination in step S200 is affirmative, the control of “phase1” is completed, and “phase” is set to “2” (step S210). This is the time t2 in FIG. Then, it is determined whether or not slippage has occurred in the lockup clutch 11 (step S220). If a negative determination is made in step S200 because the predetermined time has not elapsed, step S210 is skipped and the process proceeds to step S220.

  This step S220 is executed for the purpose of confirming the state of the lockup clutch 11. That is, if an unintentional (or unexpected) slip occurs in the lockup clutch 11 in the process of setting a predetermined margin for the transmission torque of the lockup clutch 11, the control cannot be executed normally. The detection or determination of slippage of the lockup clutch 11 is performed by comparing the input side rotational speed (for example, the engine rotational speed Ne) and the output side rotational speed (for example, the turbine rotational speed Nt). Can be done. More specifically, it is possible to detect that slip has occurred in the lock-up clutch 11 when the difference between the rotational speeds is greater than a predetermined threshold value.

  If the control proceeds as expected, the lockup clutch 11 will not slip, so a negative determination is made in step S220. On the other hand, if an unintended slip occurs in the lockup clutch 11 for some reason, an affirmative determination is made in step S220. In this case, “phase” is set to “4” and the flag F0 is set to “ON” (step S230). Thereafter, the process proceeds to step S250. If a negative determination is made in step S220 because no slip occurs in the lockup clutch 11, step S230 is skipped and the process proceeds to step S250.

  In step S250, 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, when the predetermined time has elapsed, “phase” is set to “2” in step S210, and unintentional slip has not occurred in the lockup clutch 11, so that step S230 is skipped. Since the process proceeds to S250, “phase” is set to “2”. Therefore, a positive determination is made in step S250. In that case, the engagement pressure (hydraulic pressure) of the lock-up clutch 11 is lowered toward the second predetermined hydraulic pressure PLU2 at a predetermined reduction rate (first sweep gradient) DLPLU1 (step S260). This is the control from time t2 to time t3 in FIG.

  The first sweep gradient DLPLU1 is a reduction rate set so as to quickly reduce the engagement pressure of the lockup clutch 11 to some extent, although it is smaller than the reduction rate when the pressure is lowered to the first predetermined hydraulic pressure PLU1. . That is, as with the first predetermined oil pressure PLU1, if the engagement pressure is suddenly reduced to an engagement pressure at which the lockup clutch 11 slips, the lockup clutch 11 slips excessively due to undershoot or lockup occurs. The clutch 11 is released. In order to avoid this, if the engagement pressure is gradually lowered from a stable engagement state, the responsiveness is deteriorated. Therefore, the engagement pressure is first lowered stepwise, and then the engagement pressure is lowered with a certain large gradient.

  Next, it is determined whether or not the engagement pressure has reached the second predetermined hydraulic pressure PLU2 (step S270). This determination can be made when a predetermined time has passed, or can be made based on a detection value of a hydraulic sensor (not shown).

  The second predetermined hydraulic pressure PLU2 is a hydraulic pressure that is higher by a predetermined value than the engagement pressure with zero transmission torque margin of the lockup clutch 11, and is a pressure that does not cause the lockup clutch 11 to slip. For example, the hydraulic pressure is set when the lockup clutch 11 is switched from the disengaged state (OFF) to the engaged state (ON) during normal travel such as the state of “phase0”.

  This is because the oil pressure is added to the inertia torque of the engine 4 in addition to the margin transmission torque, and the added amount can be set to the predetermined value. Alternatively, the second predetermined hydraulic pressure PLU2 calculates the difference between the lockup hydraulic pressure when the lockup clutch 11 is switched 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 can be set as the oil pressure corrected by adding to the required engagement oil pressure.

  If the engagement pressure of the lockup clutch 11 reaches the second predetermined hydraulic pressure PLU2 and is determined affirmative in step S270, "phase" is set to "3" to proceed to the next control. (Step S280). Next, it is determined whether or not the input torque to the lockup clutch 11 at that time is in an area where a learning value to be described later is obtained (step S290). If it is determined negative in step S270 because the engagement pressure has not reached the second predetermined pressure PLU2, step S280 is skipped to prevent the next control from proceeding. Proceed to S290.

  The control described here is for controlling the engagement pressure of the lockup clutch 11 to a hydraulic pressure at which a predetermined margin is generated in the transmission torque. For this purpose, it is first necessary to determine a state in which the margin is zero. However, the engagement pressure corresponding to the state where the margin is zero differs for each input torque to the lockup clutch 11. Therefore, when an engagement pressure that gives a predetermined margin for the transmission torque is obtained, the engagement pressure is learned by storing it in correspondence with the input torque at that time. The learning is as described later. Therefore, when the learning value has already been obtained, unnecessary control can be omitted by using it, so whether or not the input torque at that time is in the torque region where the learning value is obtained. It was decided to judge.

  Therefore, if the input torque at that time is in the torque region where the learned value is obtained and the determination in step S290 is affirmative, “phase” is set to “ 6 ″ is set (step S300), and then the process proceeds to step S310. Note that if the input torque at that time is not in the torque region where the learned value is obtained and the determination is negative in step S290, the control using the learned value cannot proceed, so step S290 is not performed. Skip to step S310.

  This step S310 and the subsequent step S320 are the same control steps as the aforementioned step S220 and the subsequent step S230. That is, in the process up to step S290 or step S300, the engagement pressure of the lockup clutch 11 is reduced and the input torque may change. Determination is made (step S310).

  If the lock-up clutch 11 has slipped and the determination in step S310 is affirmative, the slip is unintended (or not assumed), so that the slip has been dealt with. In order to proceed to control, “phase” is set to “4”, and the flag F0 is set to “ON” (step S320). Thereafter, the process proceeds to step S120. If it is determined in step S310 that the lockup clutch 11 does not slip, the process skips step S320 and proceeds to step S330.

  In step S330, 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 this state, if the input torque is a region where the learning value is not obtained, “phase” in step S300 is not rewritten, and if no unintended slip occurs, “phase” in step S320 is obtained. "Is not rewritten," phase "is" 3 ", and therefore affirmative determination is made in step S330. In that case, the engagement pressure (hydraulic pressure) of the lock-up clutch 11 is decreased at a predetermined decrease rate (second sweep gradient) DLPLU2 (step S340). This is the control from time t3 to time t4 in FIG.

  The second sweep gradient DLPLU2 is a lowering rate than the first sweep gradient 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 with a slight change in the hydraulic pressure, and therefore the engagement pressure is reduced to prevent the slippage from becoming excessive. The rate was set small. In other words, it is for avoiding hydraulic undershoot or excessive slip resulting from the release or release of the lockup clutch 11.

  Next, it is determined whether or not the input torque to the lock-up clutch 11 at that time is in an area where a learning value to be described later is obtained (step S350). This step S350 is a determination step similar to step S290 described above, and is used when a learning value for the engagement pressure has already been obtained.

  Therefore, if the determination in step S350 is affirmative, “phase” is set to “6” in order to proceed to control using the learning value (step S360). Next, the process proceeds to step S370. On the contrary, if the input torque to the lock-up clutch 11 is a torque in a region where the learning value is not obtained, the process proceeds to step S370 without rewriting “phase”.

  The hydraulic pressure reduction control in step S340 is a final control in the hydraulic pressure reduction control for causing the lockup clutch 11 in the engaged state to slip. Therefore, in step S370, the hydraulic pressure reduction control is performed. It is determined whether or not an error has occurred. This determination is made by comparing the rotational speed on the input side with the rotational speed on the output side, or comparing the rotational speed difference with a predetermined threshold value, as in step S220 and step S310 described above. be able to. More specifically, the slippage of the lockup clutch 11 detected in step S370 is a slight slip caused by gradually decreasing the engagement pressure. Specifically, the slippage on the input side of the lockup clutch 11 is determined. When the rotation speed difference between the rotation speed and the rotation speed on the output side is equal to or higher than a predetermined rotation speed (for example, 50 rpm), the slip of the lockup clutch 11 is continued. Can be detected.

  If a slight slip occurs in the lockup clutch 11 and a positive determination is made in step S370, “phase” is set to “4” in order to proceed to the next control (step S380). Then, the process proceeds to step S390. On the other hand, if a negative determination is made in step S370 because the lock-up clutch 11 has not yet slipped, it is not possible to proceed to the next control, so that “phase” is not rewritten (by skipping step S380). ), And proceeds to step S390.

  In step S390, it is determined whether or not “phase” is set to “4”. When the engagement pressure of the lock-up clutch 11 is reduced by the second sweep gradient DLPLU2 and slipping occurs as the lock-up clutch 11 assumes, “phase” is set to “4” in step S380. Thus, a positive determination is made in step S390.

  This state is a state in which the engagement pressure of the lockup clutch 11 is slightly lower than the engagement pressure with zero transmission torque margin. Therefore, after the slip of the lockup clutch 11 is detected, the engagement hydraulic pressure is increased by the third sweep gradient (hydraulic pressure increase rate) DLPLU3 (step S400). This is a control for re-engaging the lock-up clutch 11 from the slight slip state, and the third sweep gradient DLPLU3 is set to the minimum gradient in order to re-engage with the transmission torque margin being zero. Is done. That is, the hydraulic pressure for engaging the lockup clutch 11 is increased very little by little. This is the control from time t4 to time t5 in FIG.

  Next, it is determined whether or not the lockup clutch 11 has started to have a torque capacity (step S410). Specifically, this determination is based on the change rate Δ (Ne−Nin) of the difference between the engine speed Ne that is the input speed of the lockup clutch 11 and the input speed Nin of the continuously variable transmission mechanism 1 that is the output speed. ) Is smaller than a predetermined criterion value DNEIN. That is, when the torque capacity of the lockup clutch 11 is smaller than the torque acting on the lockup clutch 11, slippage occurs and the difference between the input rotation speed and the output rotation speed increases, and the input is performed in the opposite direction. If the torque capacity is sufficiently large with respect to the torque, the slip rotation speed decreases so that the lockup clutch 11 is completely engaged.

  Therefore, if the determination reference value DNEIN is set to, for example, zero or a negative value, it is possible to detect that the slip is toward convergence by making a positive determination in step S410. The convergence of the slip is based on the fact that the torque capacity (that is, the engagement pressure) is a necessary and sufficient value with respect to the torque acting on the lock-up clutch 11, and therefore the torque capacity at that time, that is, the engagement pressure. However, the pressure is such that the lock-up clutch 11 is re-engaged without slipping.

  Further, at the time when the determination in step S410 is affirmative, although the slip of the lockup clutch 11 is converging, since the slip has not ended, no large inertia torque is generated due to the rotation fluctuation. The engagement pressure of the lockup clutch 11 at the time is an engagement pressure corresponding to a torque that does not substantially include a transient inertia torque. In other words, this corresponds to the minimum engagement pressure required to re-engage the lockup clutch 11. Therefore, the engagement pressure at this time corresponds to “the engagement pressure at which the clutch is re-engaged” in the present invention.

  Therefore, if the determination in step S410 is affirmative, it is determined whether or not the flag F1 is "ON" (step S420). If the flag F1 is "OFF", a negative determination is made in step S420. In this case, the engagement pressure command value PLUTT of the lockup clutch 11 output at that time is obtained from the engagement pressure obtained by applying a predetermined margin pressure to the engagement pressure PLUEXC of the lockup clutch 11 at that time. The learning value DPLU1 is obtained by subtraction, and at the same time, the flag F1 is set to “ON” (step S430). Thereafter, the process proceeds to step S440. Here, the above-mentioned “applying the predetermined margin pressure” may be to obtain a value obtained by multiplying the engagement pressure at the time when the determination is affirmative in step S410 by a predetermined coefficient SF (> 1), or in advance. It is also possible to add a predetermined margin pressure.

  Since the flag F1 is a flag that is “ON” by calculating the learning value DPLU1, if the learning value DPLU1 has already been calculated, the determination in step S420 is affirmative. . In this case, the process proceeds to step S440 without calculating the learning value DPLU1 again (that is, skipping step S430). Further, when the change rate Δ (Ne−Nin) of the difference between the input and output rotational speeds of the lockup clutch 11 is equal to or larger than the determination reference value DNEIN, the process proceeds to step S440.

  In step S440, 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. If the transmission torque margin is zero, the difference between the input rotation speed and the output rotation speed of the lockup clutch 11 is eliminated, but this is the same as when the transmission torque margin is excessive. It is not always possible to accurately detect re-engagement with zero margin. Therefore, in a state where the engagement pressure is increased with the third sweep gradient DLPLU3, a state where the difference in rotational speed between the input rotational speed and the output rotational speed of the lockup clutch 11 is smaller than a predetermined value (for example, 50 rpm) is predetermined. When the time (for example, 100 ms) continues, the determination of the re-engagement of the lockup clutch 11 is established. This is the time t5 in FIG. Note that the engagement pressure of the lock-up clutch 11 at this time is an engagement pressure set according to the input torque.

  Since the control of “phase4” is thus completed, “phase” is set to “5” in order to proceed to the next control (step S450). Subsequently, it is determined whether or not the aforementioned flag F0 is “ON” (step S460). As described above, the flag F0 is set to “ON” when slippage of the lockup clutch 11 that is not intended (or not assumed) is detected in the process of controlling the engagement pressure (steps S230 and S320). Therefore, in step S460, it is determined whether or not the lockup clutch 11 is re-engaged after an unintended slip.

  Therefore, if the determination in step S460 is affirmative, "phase" is set to "3" and the flag F0 is set in order to perform the control of "phase3" corresponding to the unintentional slip of the lockup clutch 11. Is set to “OFF” (step S470). Thereafter, the process proceeds to step S490.

  On the other hand, if a negative determination is made in step S460 because the lock-up clutch 11 is re-engaged after the intended slip, it is determined whether or not the flag F2 is "ON" (step S480). That is, it is determined whether or not the input torque has changed across the region. If an affirmative determination is made in step S480, the input torque has changed and the state premised on the learning of the engagement pressure has changed, so the process proceeds to step S470 and the control of the "phase3" is performed. To do so, "phase" is set to "3" and flag F0 is set to "OFF". That is, the lock-up clutch 11 is released and then re-engaged. This is because the engagement pressure is learned again. On the other hand, if a negative determination is made in step S480, that is, if there is no change in input torque, the process proceeds to step S490.

  In step S490, it is determined whether or not “phase” is set to “5”. As described above, the lockup clutch 11 is slightly slipped by slowly decreasing the engagement pressure, and then the engagement pressure is increased with the minimum gradient, so that the determination of re-engagement of the lockup clutch 11 is established. For example, since “phase” is set to “5”, an affirmative determination is made in step S490. In other words, if the behavior of the lockup clutch 11 changes as expected due to the change in the engagement pressure, the control proceeds to “phase 5”.

  If the determination in step S490 is affirmative, the engagement hydraulic pressure of the lockup clutch 11 is determined to be the hydraulic pressure at the end of “phase4” (time t5 in FIG. 7), that is, the re-engagement of the lockup clutch 11. The hydraulic pressure at the time (the hydraulic pressure corresponding to the input torque) is set (step S500). Then, it is determined whether or not a predetermined time has elapsed (step S510). This is a time period from the time t5 to the time t6 in FIG. 7 and a predetermined time for stabilizing the engagement hydraulic pressure of the lockup clutch 11 at the hydraulic pressure at the time t5.

  If a positive determination is made in step S510 after the predetermined time has elapsed, it is determined whether or not the learning value DPLU1 described above is within a predetermined range (step S520). This determination can be made, for example, by comparing the calculated learning value DPLU1 with a predetermined determination reference value, or by comparing the magnitude with the average of the learning values in a predetermined number of torque regions, and the difference is If it is larger, it can be determined by determining that it is out of the predetermined range, and it may be determined based on the average value of the learning values DPLU1 obtained continuously.

  If there is no abnormality in the hydraulic control system, friction material in the lockup clutch 11 or change in the fluid of the torque converter 3, the learning value DPLU1 falls within a predetermined range, but there is an abnormality. As a result, the learning value becomes extremely large. That is, in step S520, it is determined whether learning has been performed normally.

  If the learning value DPLU1 is within the predetermined range and an affirmative determination is made in step S520, “phase” is set to “6” in order to proceed to the next control (step S530). Then, the learning value DPLU1 is stored (step S540).

  That is, after causing the lockup clutch 11 to slip once, an engagement pressure obtained by applying a predetermined margin pressure to the engagement pressure at which the lockup clutch 11 is reengaged, and an engagement pressure corresponding to the input torque are preliminarily set. The learning value DPLU1 is stored as a value for correcting the engagement pressure of the lockup clutch 11 based on the difference from the set or stored engagement pressure.

  The learned value DPLU1 divides the input torque into a plurality of predetermined areas, stores each area, and holds it as a map. Therefore, the determinations in step S290 and step S350 described above are determinations based on the presence or absence of the learning value obtained in this way.

  On the other hand, if the learning value DPLU1 exceeds the predetermined range and the determination is negative in step S520, “phase” is set to “3” to perform learning again (step S550). Further, in order to reflect the learned value DPLU1 obtained even if the value exceeds the predetermined range in the control of the clamping pressure of the continuously variable transmission mechanism 1, the learned value DPLU1 obtained in step S430 described above is a temporary learned value. (Step S560). Then, it is determined whether or not the absolute value of the average value of the provisional learning value DPLU1 is equal to or greater than a predetermined value (step S570). If the determination in step S570 is affirmative, the provisional learning value DPLU1 is largely biased, so that the flag F3 is set to "ON" (step S580).

  On the other hand, if a negative determination is made in step S570, it is determined whether or not the number of provisional learning values DPLU1 exceeding a predetermined value is a predetermined number or more (step S590). That is, it is determined whether the average value is equal to or less than a predetermined value, but whether there are too many or too small provisional learning values DPLU1. If this determination result is affirmative, it is considered that there is some abnormality, so that the routine proceeds to step S580 and the flag F3 is set to "ON". On the other hand, if a negative determination is made, the flag F3 is set to “OFF” (step S600). That is, the control for reflecting the provisional learning value DPLU1 in the clamping pressure of the continuously variable transmission mechanism 1 is not performed.

  After step S540 or step S580 or step S600, the process proceeds to step S610. If a negative determination is made in step S510 because the predetermined time has not elapsed, the process immediately proceeds to step S610. In this case, “phase” is not rewritten and is maintained at “5”.

  Further, it is determined whether or not an unintended slip of the lockup clutch 11 has occurred even at this time. This is the control of step S610. This is a determination step similar to step S220 or step S310 described above. Therefore, if the determination is affirmative in step S610, "phase" is "4" in order to proceed to the control corresponding to the slip. And the flag F0 is set to "ON" (step S620). Thereafter, the process proceeds to step S630. If it is determined in step S610 that the lockup clutch 11 does not slip, the process skips step S620 and proceeds to step S630.

  In step S630, it is determined whether or not “phase” is set to “6”. As described above, the difference between the engagement pressure obtained by adding a predetermined margin pressure to the engagement pressure at which the lockup clutch 11 is re-engaged, and the engagement pressure commanded or set according to the input torque at that time Is stored as the learned value DPLU1, and if there is no abnormality in the learned value DPLU1, since “phase” is set to “6”, unless the unintentional slip of the lockup clutch 11 is detected, the step A positive determination is made in S630.

  In this case, the above learning value DPLU1 is added as the correction value to the engagement pressure PLUTT obtained based on the input torque as the engagement pressure of the lockup clutch 11 (if the learning value DPLU1 is a negative value, The engagement pressure of the lockup clutch 11 is obtained by subtraction) (step S640). That is, the engagement pressure obtained in advance is corrected by the learning value DPLU1. As a result, as the engagement pressure of the lock-up clutch 11, a predetermined predetermined surplus hydraulic pressure is added to the engagement pressure (hydraulic pressure with zero margin) that has no margin in transmission torque with respect to the input torque at that time. The hydraulic pressure that reflects the actual state of the continuously variable transmission mechanism 1 or the drive system is set. This is the control at time t6 in FIG. The surplus hydraulic pressure DPLU2 is not likely to slip in the lock-up clutch 11 in a steady or quasi-steady running state, and when the torque exceeding the torque acting in the steady or quasi-steady running state is applied. Is a hydraulic pressure to the extent that the lockup clutch 11 slips.

  Since the input torque to the lockup clutch 11 may change in the state where the engagement hydraulic pressure of the lockup clutch 11 is set as described above, the input torque enters the unlearned region following step S640 above. Whether or not the above learning value has not been obtained has been changed (step S650). The situation at that time is that the lockup clutch 11 is engaged without slipping, and the engagement pressure is a hydraulic pressure with a small margin of transmission torque.

  Therefore, if the determination in step S650 is affirmative, the control of “phase 2” is executed in order to perform the learning by causing a slight slip again. That is, “phase” is set to “2” (step S660). Then, the process proceeds to step S670. If the negative determination is made in step S650 because the input torque is in the region where the learned value is obtained, the process immediately proceeds to step S670 without changing “phase”.

  Even at this time, it is determined whether or not an unexpected slip of the lockup clutch 11 has occurred. This is the control in step S670. This is a determination step similar to step S220, step S310, or step S610 described above. Therefore, if a positive determination is made in step S670, "phase" is set to proceed to control corresponding to the slip. “4” is set and the flag F0 is set to “ON” (step S680). Thereafter, the process proceeds to step S690. Note that if a negative determination is made in step S670 because no slip occurs in the lockup clutch 11, step S680 is skipped and the process proceeds to step S690.

  In step S690, it is determined whether or not “phase” is set to “6”. If this determination result is negative, this routine is once terminated. On the other hand, if a positive determination is made, it is determined whether or not the provisional learning value DPLU1 described above should be reflected in the clamping pressure of the continuously variable transmission mechanism 1 (step S700). Specifically, it is determined whether or not the aforementioned flag F3 is "OFF". Even if the learning value DPLU1 is not within the predetermined range, if the absolute value of the average value is within the predetermined value or the so-called abnormality determination such as a small number of absolute values exceeding the predetermined value is not established. The flag F3 is set to “OFF” (step S600). Therefore, if the determination in step S700 is affirmative, it is not necessary to reflect the provisional learning value DPLU1 in the control of the clamping pressure of the continuously variable transmission mechanism 1, so that the belt clamping pressure of the continuously variable transmission mechanism 1 is the transmission torque. (Step S710). As shown in FIG. 7, the pinching pressure is a pressure obtained by adding a predetermined value to a pressure with zero transmission torque margin. The margin of transmission torque in the continuously variable transmission mechanism 1 set in this way is larger than the margin of transmission torque in the lock-up clutch 11, so that when the drive torque, negative torque or the like changes, the lock-up clutch 11 Slip occurs prior to the continuously variable transmission mechanism 1.

  On the other hand, if the flag F3 is set to “ON” and a negative determination is made in step S700, the belt clamping pressure of the continuously variable transmission mechanism 1 is corrected based on the temporary learning value DPLU1 (step S700). S720). This correction may be an increase correction of a predetermined value as a pressure that gives a predetermined margin to the transmission torque of the continuously variable transmission mechanism 1 or a pressure that gives a margin to the transmission torque. The control itself to be lowered may be prohibited. Further, the correction in step S720 may be performed only when the belt clamping pressure correction based on the provisional learning value DPLU1 corrects the belt clamping pressure to the increase side. This is to prevent slippage in the continuously variable transmission mechanism 1 by avoiding erroneous lowering correction based on some abnormality.

  In the case where a negative determination is made in step S110 shown in FIG. 1 and a positive determination is made in step S150, that is, when the control precondition is not satisfied and when the control end condition is satisfied, “phase "Is set to" 0 "(step S240). In that case, the process immediately proceeds to step S690 shown in FIG. 6, but since this determination is negative, this routine is terminated. In that case, so-called torque fuse control that lowers the engagement pressure (transmission torque) of the lockup clutch 11 and lowers the clamping pressure (transmission torque) of the continuously variable transmission mechanism 1 is terminated or prohibited. And the clamping pressure is increased to the normal pressure. This is the state at time t7 in FIG.

  Therefore, according to the control device of the present invention that performs the above control, a predetermined margin pressure is applied to the engagement pressure for re-engaging the clutch such as the lockup clutch 11 connected in series to the continuously variable transmission mechanism 1. A correction value for the clutch engagement pressure is obtained based on the engagement pressure to which the margin pressure is applied, such as obtaining the applied engagement pressure and obtaining a difference between the engagement pressure and a preset engagement pressure. Since learning is performed, the clutch can be engaged with the engagement pressure reflecting the actual state of the continuously variable transmission mechanism 1 and the drive system including the continuously variable transmission mechanism 1. That is, when the clutch is caused to function as a so-called torque fuse for the continuously variable transmission mechanism 1, the engagement pressure of the clutch can be optimized. Therefore, it is possible to avoid a situation in which slipping of the clutch such as the lockup clutch 11 repeatedly occurs or the power transmission efficiency of the drive system is reduced and the fuel consumption is deteriorated accordingly.

  When the control shown in FIGS. 1 to 6 is executed, the engagement pressure that re-engages the lockup clutch 11 substantially corresponds to the torque that does not include the inertia torque. Since the resultant pressure is required, the clutch engagement pressure can be optimized also in this respect.

  Further, when the learning value exceeds the predetermined range and there is a deviation, the learning value deviation is reflected in the control amount for setting the transmission torque such as the belt clamping pressure of the continuously variable transmission mechanism 1. The transmission torque margin with respect to the transmission torque that causes slippage in the mechanism 1 can be set to be always larger than the transmission torque margin of the clutches arranged in series therewith. As a result, the clutch can reliably function as a so-called torque fuse. In particular, if the correction of the transmission torque of the continuously variable transmission mechanism 1 is limited to the increase correction, the transmission torque of the continuously variable transmission mechanism 1 is reduced even if a situation occurs in which the learning torque accompanied by mislearning or abnormality occurs. Since the transmission torque of the speed change mechanism 1 cannot be reduced, slipping in the continuously variable speed change mechanism 1 can be prevented or suppressed in advance.

  Furthermore, when the engine torque or the negative torque on the drive wheel side changes suddenly in a steady or quasi-steady running state, the lock-up clutch 11 slips ahead of the continuously variable transmission mechanism 1. It is possible to reliably prevent the continuously variable transmission mechanism 1 from slipping. And while preventing the slip of the continuously variable transmission mechanism 1, the clamping pressure can be made as low as possible, so that the power transmission efficiency in the continuously variable transmission mechanism 1 is improved and the fuel efficiency is improved. Can be improved.

  Note that the routines shown in FIGS. 1 to 6 are repeatedly executed every predetermined short time. Therefore, in that process, the input torque at that time may be in the area where the learning value has already been obtained. In this case, the following control is performed.

  In other words, if the input torque is in the region where the learning value is obtained, the determination is affirmative in step S290 shown in FIG. 2, and "phase" is set to "6" (step S300). This determination is performed while the engagement pressure is lowered to the first predetermined oil pressure PLU1 stepwise in “phase1” and then the engagement pressure is lowered by the first sweep gradient DLPLU1 in “phase2”.

  When “phase” is set to “6” in step S300, a negative determination is made in any of steps S330, S390, and S490 for determining “phase”. Therefore, the process immediately proceeds to step S630, where a positive determination is made. The control after step S630 is as already described.

  Therefore, when the learning value has already been obtained, the control of “phase1” for setting the first predetermined oil pressure PLU1 based on the input torque is executed, and then immediately reduced to the engagement pressure corrected with the learning value DPLU1. (Step S640). In this case, since the engagement hydraulic pressure to be set is close to the engagement hydraulic pressure at which the lock-up clutch 11 slips, smoothing control is performed to prevent the lock-up clutch 11 from being released or excessively slipped due to a hydraulic undershoot. It is preferable to execute the control for lowering the engagement hydraulic pressure.

  When the learning value is obtained in this way, the engagement pressure of the lockup clutch 11 can be controlled to be lowered using the learning value, so that the control of “phase2” to “phase5” described above is omitted. Rapid control is possible.

  In addition, the input torque changes in the above-described series of control processes. As a result, the input torque enters the region where the learning value is not obtained from the region where the learning value is obtained, and conversely, the learning value is obtained. There is a case in which a learning value is obtained from a non-registered region. In the former case, since it is not possible to perform control using the learning value, it is necessary to perform learning. In the latter case, control for obtaining the learning value is not required, and control using the learning value is not necessary. It becomes possible.

  Specifically, when the input torque of the lockup clutch 11 changes from the torque region where the learned value is obtained to the torque region where the learned value is not obtained, a negative determination is made in step S290 described above, Alternatively, a negative determination is made in step S350. Therefore, if the input torque changes to the torque range where the learning value is not obtained before setting the engagement hydraulic pressure with the transmission torque margin zero and adding the predetermined margin hydraulic pressure, the `` phase1 '' Or a series of control of "phase6" is performed in the order mentioned above.

  On the other hand, if the input hydraulic pressure is changed to a torque region where the learned value is not obtained after setting the engagement hydraulic pressure that causes a predetermined margin in the transmission torque of the lockup clutch 11, a positive determination is made in step S650. To be judged. Accordingly, “phase” is set to “2”, so that control of “phase2” is executed. This is a control in the case where an affirmative determination is made in step S250 shown in FIG. 2, 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 After reaching the hydraulic pressure PLU2, 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 the re-engagement is performed. After the detection, an engagement pressure obtained by adding a predetermined hydraulic pressure to the hydraulic pressure at that time is set. This is the control after step S250 of the series of controls described above.

  On the other hand, as an example of the case where the input torque changes from the torque region where the learned value is not obtained to the torque region where the learned value is obtained, after stepping down to the first predetermined hydraulic pressure PLU1 (the control of “phase1” is performed) After completion), when the input torque of the lockup clutch 11 enters the torque region where the learning value is obtained, the determination in the above step S290 shown in FIG. The control in this case is the same as that in the case where the learning value is obtained, and immediately proceeds to step S630, where the engagement hydraulic pressure based on the learning value that gives a predetermined margin to the transmission torque of the lockup clutch 11 is set. Setting is executed (step S640).

  Further, when the input torque changes to the torque region where the learned value is obtained after the engagement pressure is reduced to the second predetermined hydraulic pressure PLU2, a positive determination is made in step S350 shown in FIG. As a result, since “phase” is set to “6”, the process immediately proceeds to step S630, and the engagement pressure is set based on the learned value so that a predetermined margin is generated in the transmission torque.

  Note that after the slight slip of the lock-up 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 selected according to the progress of the engagement pressure control. The Therefore, the above-described learning of the engagement pressure can be performed, and at the same time, unnecessary control that is not necessary can be omitted.

  By the way, in the series of processes for controlling the engagement hydraulic pressure of the lock-up clutch 11 so that a predetermined margin is generated in the transmission torque, the lock-up clutch 11 is locked up due to a decrease in the engagement hydraulic pressure, a change in input torque, or the like. The clutch 11 may slip. This is detected in, for example, step S220, step S310, step S370, step S610, and step S670.

  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 engagement pressure is at the second predetermined pressure PLU2, a positive determination is made in step S220 or step S310. . In any of these cases, “phase” is set to “4” and the flag F0 is controlled to be “ON” (steps S230 and S320). As a result, the process proceeds to step S390 shown in FIG. 4, and the subsequent control is sequentially executed, and the engagement pressure is slowly increased.

  As a result, the lockup clutch 11 once slipped is re-engaged (step S128). In this case, since the flag F0 is set to “ON”, “phase” is set to “3”. (Step S460, Step S470) Therefore, the control returns to “phase3”. Therefore, since step S530 shown in FIG. 5 is not reached, learning is not performed. This corresponds to prohibition of learning.

  As described above, when an unintended slip of the lock-up clutch 11 occurs in the control process, the lock-up clutch 11 is returned to the engaged state, and again a decrease in the engagement pressure, detection of a slight slip, an increase in pressure, etc. The series of controls described above are executed. At the same time, learning of the engagement pressure at which the margin of transmission torque becomes zero, or learning of the engagement pressure at which a predetermined margin occurs in the transmission torque including this is prohibited.

  Further, when slippage of the lockup clutch 11 occurs when the pressure is reduced from the second predetermined hydraulic pressure PLU2, a positive determination is made in step S370 shown in FIG. Since this is an intended slip, “phase” is set to “4” (step S380), and then the above-described series of control is executed. In other words, there is no difference from the above series of controls.

  Further, if an unintended slip occurs after the lockup clutch 11 is re-engaged, an affirmative determination is made in step S610. In this case, since “phase” is set to “4” and the flag F0 is controlled to be “ON” (step S620), the process proceeds to step S390 shown in FIG. The engagement pressure is slowly increased. This is similar to the example described above.

  In this way, in the above control, when the lockup clutch 11 slips unintentionally, the control to be performed next is selected according to the control status at that time. It is possible to avoid inconveniences such as excessive slipping or repeated unnecessary control.

  Also, in the flowcharts shown in FIG. 1 to FIG. 6, when a negative determination is made in the determination steps S180, S250, S330, S390, S490, and S630 for “phase”, the steps after the step in which the determination is made Proceed to the determination step for “phase” in order. If a negative determination is made in the final determination step S690 for “phase”, the routine shown in FIGS. 1 to 6 is exited.

  The above-described control for causing the lock-up clutch 11 to function as a so-called torque fuse for the continuously variable transmission mechanism 1 improves the power transmission efficiency by reducing the belt clamping pressure of the continuously variable transmission mechanism 1 as much as possible. In this control, slippage does not occur in the continuously variable transmission mechanism 1 due to a strong disturbance. Accordingly, the control start condition is, for example, that the vehicle is in a steady running state or a quasi-steady running state such that the vehicle is running at a constant speed on a flat road at a predetermined engine load or lower, or the lockup clutch 11 or the continuously variable transmission. For example, the mechanism 1 is not slipped. Therefore, when this control start condition is not satisfied, that is, when the control end condition is satisfied, the control for lowering the engagement pressure of the lockup clutch 11 and the belt clamping pressure of the continuously variable transmission mechanism 1 is finished and the pressures are increased. I will let you.

  The increase control of the engagement pressure of the lockup clutch 11 at the end of the control is executed as described below. FIGS. 8 and 9 are flowcharts for explaining the control, and are obtained by changing or adding a part of the flowcharts shown in FIGS. Specifically, in FIG. 8, when the control end condition is satisfied, an affirmative determination is made in step S150. In this case, it is determined whether or not “phase” is set to “6”. (Step S730). That is, the lockup clutch 11 is engaged with an engagement pressure obtained by applying a predetermined margin pressure to the engagement pressure for re-engaging the lockup clutch 11, or the learning value DPLU1 for that purpose is being determined. Is judged.

  If a negative determination is made in step S730, the above-described control for obtaining the learning value is being executed. Therefore, in order to detect the occurrence of slipping of the lockup clutch 11 during the learning control, It is determined whether or not the lockup clutch 11 is slipping (step S740). If a negative determination is made in step S740 because no slip has occurred in the lockup clutch 11, the engagement pressure of the lockup clutch 11 is set to the maximum pressure and “phase” is set to “0”. (Step S750). This step S750 replaces step S240 shown in FIG. Thereafter, the process proceeds to step S690 shown in FIG.

  That is, if slippage does not occur in the lockup clutch 11 when the control end condition is satisfied, the engagement pressure of the lockup clutch 11 is increased to the line pressure that is the original pressure of the control device or its correction pressure, The lockup clutch 11 is fully engaged. In that case, since the rotation change accompanying the lock-up clutch 11 becoming a complete engagement state does not arise, an inertia force and the shock resulting from it do not generate | occur | produce.

  On the other hand, if the lockup clutch 11 has slipped and the determination in step S740 is affirmative, the flag F4 is set to "ON" (step S760), and then "phase" is set to "7". (Step S770). Note that if the determination in step S730 is affirmative, the process proceeds to step S770 and “phase” is set to “7”. Then, the process proceeds to step S180 shown in FIG.

  The control content of this “phase 7” is shown in a flowchart in FIG. The flowchart shown in FIG. 9 is a flowchart inserted between step S680 and step S690 in FIG. 6 described above. First, it is determined whether or not “phase” is set to “7”. (Step S681). If a negative determination is made in step S681, the process immediately proceeds to step S690, and control according to the set “phase” is executed. On the other hand, if the determination in step S681 is affirmative, it is determined whether or not the flag F4 is "ON" (step S682).

  As described above, the flag F4 is “ON” when slippage is detected in the lockup clutch 11 after the control end condition is satisfied. Therefore, if a negative determination is made in step S682, it is determined whether a predetermined time has passed (step S683). During the predetermined time, when it is determined in step S150 that the control end condition is satisfied, the belt clamping pressure of the continuously variable transmission mechanism 1 is increased to the normal pressure (maximum pressure), so this increase control is completed. This is set as the time until the belt is clamped (that is, until the belt clamping pressure is stabilized at the maximum pressure). This is the time from the time t7 to the time t8 in the time chart of FIG. As a result, since the engagement pressure of the lockup clutch 11 cannot be increased at time t7, the belt clamping pressure of the continuously variable transmission mechanism 1 increases first, and then the engagement pressure of the lockup clutch 11 increases. Will be allowed to.

  Therefore, if a negative determination is made in step S683, the control for engaging the lockup clutch 11 with the engagement pressure obtained by correcting the engagement pressure PLUTT set according to the input torque with the learning value DPLU1 is continued. (Step S684). Thereafter, the process proceeds to step S690. In that case, since judgment and control are executed in the order of step S730, step S740, and step S750 in FIG. 8 described above, the engagement pressure of the lockup clutch 11 is increased to the maximum pressure, and the lockup clutch 11 is completely The engaged state is established. In addition, since the slip has not arisen, the shock accompanying setting to a perfect engagement state does not generate | occur | produce.

  On the other hand, if the lockup clutch 11 has slipped and the determination is affirmative in step S682, or if the predetermined time has elapsed and the determination is affirmative in step S683, the lockup clutch 11 It is determined whether or not the engagement determination of 11 is established (step S685). That is, it is determined whether or not the lock-up clutch 11 is slipping at an engagement pressure obtained by applying a predetermined margin pressure to the hydraulic pressure for re-engaging the lock-up clutch 11.

  If a negative determination is made in step S685 due to slippage in the lockup clutch 11, the engagement pressure of the lockup clutch 11 is gradually increased (step S686). That is, it is swept up. Thereafter, the process proceeds to step S690. In that case, since the determination in step S740 is affirmative, the sweep-up of the engagement pressure of the lockup clutch 11 is continued.

  If the lockup clutch 11 is engaged as a result of gradually increasing the engagement pressure of the lockup clutch 11, a positive determination is made in step S685. In this case, the flag F4 is set to “OFF” (step S687), and then the process proceeds to step S690. In this case, since a negative determination is made in step S740 described above, the engagement pressure of the lockup clutch 11 is increased to the maximum value (step S750). That is, since the lock-up clutch 11 is set to a fully engaged state without slipping, rotation fluctuations and shocks resulting from it are not generated. The other control is the same as the control shown in FIGS.

  Therefore, when the control for causing the lockup clutch 11 to function as a so-called torque fuse is terminated, when the engagement pressure of the lockup clutch 11 is increased to the maximum value, the belt of the continuously variable transmission mechanism 1 precedes the lockup clutch 11. Since the clamping pressure is increased, the so-called margin of the transmission torque of the lockup clutch 11 can be maintained to be smaller than the so-called margin of the transmission torque of the continuously variable transmission mechanism 1 even in the transitional end state of the control. Even if the input torque fluctuates at the end of the transition, the slip-up of the lockup clutch 11 is prevented to prevent or suppress the torque acting on the continuously variable transmission mechanism 1 from becoming excessive. Slip can be avoided.

  Further, when slipping occurs when the engagement pressure of the lock-up clutch 11 is maximized, the engagement pressure is swept up, so that the lock-up clutch 11 is suddenly engaged or a shock is caused accordingly. Can be avoided in advance.

  By the way, in the control device of the present invention configured to execute the above-described control, after the engagement pressure of a clutch functioning as a so-called torque fuse such as the lockup clutch 11 is once reduced, the engagement pressure is reduced. When it is gradually increased and reengaged, the pressure in a state where the difference between the input rotational speed and the output rotational speed of the clutch is gradually reduced is the engagement pressure with a so-called margin (minimum in a range where no slip occurs). (Engagement pressure). That is, the lock-up clutch 11 slips. On the other hand, the so-called marginal transmission torque is a transmission torque in a state in which the lock-up clutch 11 is not slipped, and is obtained by an engagement pressure obtained by applying a predetermined margin pressure to the above-described engagement pressure for re-engagement. Torque capacity.

  However, since the friction coefficient of the friction clutch such as the lock-up clutch 11 is generally different depending on the deviation (slip rate) of the input / output speed, there is a difference in the input / output speed. The so-called zero-margin engagement pressure and the so-called zero-margin engagement pressure in a state where there is no difference in input / output rotational speed are different due to the difference in friction coefficient.

  A general relationship between the friction coefficient and the slip ratio is shown in FIG. That is, the friction coefficient μ0 at the time of complete engagement with no input / output rotational speed difference is smaller than the friction coefficient μ1 at the time of engagement determination in which the input / output rotational speed difference is generated. Therefore, if the engagement pressure at the time of engagement determination is adopted as an engagement pressure with zero so-called margin at the time of complete engagement, the engagement pressure becomes insufficient. In other words, a so-called transmission torque margin at the time of complete engagement is insufficient. Therefore, when the ratio (μ1 / μ0) of these friction coefficients μ1 and μ0 is defined as “μ gradient magnification”, the engagement pressure at the time of engagement determination is corrected by the μ gradient magnification, so that at the time of complete engagement. Thus, the engagement pressure with zero so-called margin for slippage can be made accurate, and the engagement pressure with so-called margin pressure can be accurately set without excessive or insufficient.

  There are various factors that affect the friction coefficient of the lock-up clutch 11 (variation factors of the friction coefficient), and the friction coefficient of the lock-up clutch 11 depends on the temperature of the lubricating oil (fluid), the degree of deterioration and the composition thereof. Change. As an example, FIG. 12 shows the relationship with the oil temperature, and the higher the oil temperature, the larger the friction coefficient μ. FIG. 13 shows the relationship with the degree of fluid deterioration. When the deteriorated fluid is used, the friction coefficient μ increases and the μ gradient magnification decreases.

  The control device of the present invention takes into account the difference in the friction coefficient of the lockup clutch 11 between the engagement determination and the complete engagement, in order to set a transmission torque having a so-called predetermined margin for slipping. Learning of the correction value of the engagement pressure can be performed as follows. That is, in each control example described above, in step S430 described above, a predetermined margin pressure is applied to the engagement pressure PLUEXC at the time of engagement determination (specifically, a safety factor SF is multiplied), and the engagement pressure is determined from the value. The learned value DPLU1 is obtained by subtracting the command value PLUTT. Therefore, in the control example shown in FIG. 14, in order to make the engagement pressure PLUEXC at the time of engagement determination correspond to the friction coefficient at the time of complete engagement, the engagement pressure PLUEXC is divided by the μ gradient magnification, A predetermined margin pressure such as the safety factor SF is multiplied to the value, and the engagement pressure command value PLUTT is subtracted from the value to obtain the learning value DPLU1 (step S431). At the same time, the flag F1 is set to "ON", and then the process proceeds to step S440.

  The μ gradient magnification employed in step S431 is appropriately employed according to a predetermined physical quantity such as the temperature at that time and the degree of deterioration of the fluid used. This may be, for example, a value read from a map prepared in advance. The other control is the same as the control shown in FIGS. 1 to 6 described above or the control shown in FIGS. 8 and 9 added or replaced.

  Therefore, when the control in step S430 shown in FIG. 4 is replaced with the control in step S431 shown in FIG. 14, the actual friction coefficient is reflected in the engagement pressure of the lockup clutch 11. Therefore, the engagement pressure of the lockup clutch 11 can be optimized. Accordingly, it is possible to stably and satisfactorily control the lockup clutch 11 to function as a so-called torque fuse.

  The present invention can be applied to a control device that controls hydraulically the engagement pressure of a clutch that is connected in series to the continuously variable transmission mechanism 1 in the direction of torque transmission. In this type of hydraulic control device, the viscosity of the oil may affect the controllability of the hydraulic pressure, and the general tendency is that when the oil temperature is low, the viscosity increases and the accuracy of the hydraulic control is increased. Decreases.

  Therefore, the control device of the present invention can set the oil temperature as a control start condition or an end condition. Examples of such control are shown in FIGS. 15 and 16. FIG. 15 specifically shows the control content of step S120 described above. If the control precondition is satisfied and the determination is affirmative in step S110, whether or not steady running is being determined. That is, it is determined whether or not the determination of steady running is established (step S121). The determination of the steady running state can be performed, for example, by determining that the shaft torque of the driven pulley 20 calculated from the input torque of the continuously variable transmission mechanism 1 and the gear ratio is within a predetermined range. .

  If a negative determination is made in step S121, the start condition is not satisfied. Therefore, as in the case where the negative determination is made in step S120 described above, control such as the setting of “phase” is performed. Without proceeding to step S140. That is, control is not started.

  On the other hand, if an affirmative determination is made in step S121, it is determined whether or not the input torque at that time is in an area where a learning value has already been obtained (step S122). If the determination result is affirmative, it is determined whether or not the oil temperature is equal to or higher than a predetermined first reference value THOH1 (step S123). The first reference value THOH1 is a relatively low temperature. If the determination in step S123 is affirmative, the control start condition is satisfied and the control is started. That is, if the learning value has already been obtained, the engagement pressure control reflecting the actual state of the continuously variable transmission mechanism 1 and the drive system can be performed, so that the oil temperature is relatively low and the hydraulic control accuracy is particularly high. Even if it is not high, it is possible to execute control for causing the lockup clutch 11 to function as a so-called torque fuse.

  Therefore, if a positive determination is made in step S123, it is determined whether or not “phase” is set to “0” (step S124). If a negative determination is made in step S124, the process proceeds to step S140 in order to perform control according to the set “phase”. On the other hand, if “phase” is set to “0” and a positive determination is made in step S124, the process proceeds to step S130 to perform control in order, and “phase” is set to “1”. "Is set.

  On the other hand, if a negative determination is made in step S122, that is, if the input torque at that time is in an area where the learned value is not obtained, it is determined whether the oil temperature is equal to or higher than the second reference value THOH2. Judgment is made (step S125). The second reference value THOH2 is a temperature higher than the first reference value THOH1.

  If the determination in step S125 is affirmative, the control start condition is satisfied and control is started. That is, if the learning value is not yet obtained, it is difficult to accurately set the engagement pressure of the lock-up clutch 11 so that a predetermined margin is generated with respect to slipping. Control is started in a state where the control is stable.

  Therefore, if a positive determination is made in step S125, the process proceeds to step S124. On the other hand, if a negative determination is made in step S125, the control start condition is not satisfied, and the process proceeds to step S140 without performing control such as setting of “phase”. That is, control is not started.

  Therefore, by determining the control start condition as shown in FIG. 15, when the learning value has already been obtained, the engagement pressure of the lock-up clutch 11 is reduced even when the oil temperature is low, At the same time, the belt clamping pressure of the continuously variable transmission mechanism 1 can be lowered to perform efficient operation. In other words, fuel consumption can be improved by extending the period of driving with good power transmission efficiency associated with so-called torque fuse control of the lockup clutch 11. Further, when the learning value is not obtained, the control is started in a state where the oil temperature is somewhat high, so that the learning control of the engagement pressure and the subsequent setting control of the engagement pressure of the lockup clutch 11 are stably performed. And it can be done accurately.

  Next, end condition determination control shown in FIG. 16 will be described. FIG. 16 specifically shows the control contents of step S150 described above. After the input torque region is stored (step S140), whether or not steady running determination is being performed, that is, steady running determination is established. It is determined whether or not (step S151). This determination can be performed in the same manner as the determination in step S121 described above.

  If the determination in step S121 is negative, it means that the end condition is satisfied. Therefore, the process proceeds to step S730 as in the case where the determination is positive in step S150 shown in FIG. That is, end control is performed.

  On the other hand, if an affirmative determination is made in step S151, it is determined whether or not the input torque at that time is in an area where a learning value has already been obtained (step S152). If the determination result is affirmative, it is determined whether or not the oil temperature is lower than a predetermined third reference value THOL1 (step S153). The third reference value THOL1 is a relatively low temperature (<THOH1). If the determination in step S153 is affirmative, the control end condition is satisfied, and the process proceeds to step S730 where the end control is performed. It is carried out.

  That is, if the learning value has already been obtained, the engagement pressure control reflecting the actual state of the continuously variable transmission mechanism 1 and the drive system can be performed, so that the oil temperature is relatively low and the hydraulic control accuracy is particularly high. Even if it is not high, it is possible to execute control for causing the lockup clutch 11 to function as a so-called torque fuse. Therefore, control is continued until the oil temperature is low.

  On the other hand, if a negative determination is made in step S153 due to the high oil temperature, the end condition is not satisfied, so the routine proceeds to step S160 described above, and the lockup clutch 11 is so-called. Control to function as a torque fuse is continued.

  On the other hand, if a negative determination is made in step S152, that is, if the input torque at that time is in an area where the learned value is not obtained, whether or not the oil temperature is lower than the fourth reference value THOL2 Is determined (step S154). The fourth reference value THOL2 is a temperature (<THOH2) higher than the third reference value THOL1.

  If the determination in step S154 is affirmative, the control end condition is satisfied, and therefore the process proceeds to step S730 where end control is performed. That is, if the learning value is not yet obtained, it is difficult to accurately set the engagement pressure of the lock-up clutch 11 so that a predetermined margin is generated with respect to slipping, so that the oil temperature is relatively high. Even so, the control of the engagement pressure may become unstable, so the control is terminated.

  On the other hand, if a negative determination is made in step S154, the control end condition is not satisfied, and therefore the control proceeds to step S160 and the control for causing the lockup clutch 11 to function as a so-called torque fuse is continued. The

  Therefore, if the control shown in FIG. 16 is executed, the learning value has already been obtained, so that the lockup clutch 11 functions as a so-called torque fuse, and accordingly, the belt clamping pressure of the continuously variable transmission mechanism 1. Can be extended to a low oil temperature state, and as a result, fuel consumption can be improved. Further, when the learning value is not obtained, the control is terminated even when the oil temperature is relatively high, so that the control using the lock-up clutch 11 as a so-called torque fuse becomes unstable, and accordingly Thus, slippage of the lockup clutch 11 and the continuously variable transmission mechanism 1 can be avoided or suppressed.

  By the way, judder is known as a disadvantage of the friction clutch. Judder is a phenomenon in which clutch engagement and slipping occur repeatedly, and as a result, the torque on the output side fluctuates greatly, causing vibration of the vehicle body, etc. This is the phenomenon when the friction coefficient is completely engaged and when slipping occurs This is probably due to the difference between the two. Thus judder occurs at the transition between the sliding state and the fully engaged state.

  The control targeted by the present invention is that the clutch that functions as a so-called torque fuse for the continuously variable transmission mechanism 1 is temporarily shifted from the engaged state to the slipped state, and then the engagement pressure is increased to re-engage. The clutch is made to function as a torque fuse by applying a predetermined margin pressure to the engagement pressure for the re-engagement. This includes the control to learn the clutch engagement pressure, and in the process, the clutch is shifted from the engaged state to the slipped state, and further from the slipped state to the engaged state. There is. Therefore, in the control device of the present invention, it is preferable that the judder occurrence history is used as a control start condition or an end condition. An example of the control is shown in FIGS.

  FIG. 17 is a flowchart for determining whether or not the control start condition is satisfied. The flowchart shown in FIG. 15 is added with a step for determining whether or not there is a judder occurrence history. That is, if it is determined affirmatively in step S121 because it is in the steady running determination, it is determined whether or not the lock-up clutch 11 has judder in the past (step S126). The judder generation history may be determined for each input torque region. If the determination in step S126 is affirmative due to the presence of judder occurrence history, the process proceeds to step S140 without performing control such as setting of “phase”. That is, since the process does not proceed to any of the “phases” described above, control is not started.

  On the other hand, if a negative judgment is made in step S126 because there is no judder occurrence history, the process proceeds to step S122 described above, and the control in steps S122 to S125 is performed as described with reference to FIG. Execute.

  Therefore, if it is configured to execute the control shown in FIG. 17, if there is a judder occurrence history in the lock-up clutch 11, it is regarded as a prohibition condition for the control, and the engagement pressure of the lock-up clutch 11 is made to slip. Since the control for performing the learning for that is set to a pressure obtained by adding a predetermined margin pressure to the pressure having a margin for zero, judder of the lockup clutch 11 can be prevented.

  FIG. 18 is a flowchart for determining whether or not the control end condition is satisfied. The flowchart shown in FIG. 16 is added with a step for determining whether or not there is a judder occurrence history. That is, if it is determined affirmative in step S151 due to the determination of steady running, it is determined whether or not the lock-up clutch 11 has generated judder in the past (step S155). The judder generation history may be determined for each input torque region. If the determination in step S155 is affirmative due to the presence of judder occurrence history, the process immediately proceeds to step S730 to execute termination control. That is, the end condition is that there is a judder occurrence history. Therefore, after that, learning control for re-engaging after the lock-up clutch 11 is once slid is not executed, so that judder of the lock-up clutch 11 can be prevented.

  If a negative judgment is made in step S155 because there is no judder occurrence history, the process proceeds to step S152 described with reference to FIG. 16, and the end condition for the oil temperature is satisfied in steps S152 to S154. And the control according to the result of the determination is executed.

  If the input torque at that time is in the region where the learning value DPLU1 is obtained, the lockup clutch 11 functions as a so-called torque fuse, as can be seen from the fact that the learning value DPLU1 has already been obtained. In this case, the control may be executed without determining the presence / absence of judder occurrence history. An example thereof is shown in FIG. 19, and in the example shown here, the presence / absence of judder occurrence history is determined after step S125 in which the oil temperature is compared with the second reference value THOH2 when it is not the learned region (step S125). S126). Even if the determination is made before step S125, there is no particular change.

  Accordingly, in the control example shown in FIG. 19, when the learning value DPLU1 has already been obtained, the learning control for the engagement pressure of the lockup clutch 11 is performed on the condition that the oil temperature is equal to or higher than the first reference value THOH1. Is executed. On the other hand, in the state where the learning value is not obtained, even if the condition about the oil temperature is satisfied, if there is a judder occurrence history, a positive determination is made in step S126, so the setting of “phase” The control proceeds to step S140, and control is not started. Thus, in the configuration for executing the control shown in FIG. 19, if the learning value has already been obtained, the control for causing the lockup clutch 11 to function as a so-called torque fuse and the related learning control are executed. When the learning value is not obtained, the judder generation history is set as a control prohibition condition, and control for causing the lockup clutch 11 to function as a so-called torque fuse is prohibited.

  Further, the example shown in FIG. 20 is an example in which the judder occurrence history is used as the control end condition. In step S155 in the control example shown in FIG. 18, the learning value is not obtained and the oil temperature is In this example, the fourth reference value THOL2 or more is used. That is, even if there is no problem in controlling the hydraulic pressure due to the oil temperature being high to some extent, if there is a judder generation history in the lockup clutch 11 (when affirmative determination is made in step S155), step S730 is immediately performed. The process for ending control is started. As a result, after that, the control to re-engage after the lock-up clutch 11 is slid is not performed, so that the occurrence of judder in the lock-up clutch 11 can be prevented or suppressed.

  If the learning value is obtained, the process does not go through step S155, so the presence / absence of judder occurrence history is not set as the control end condition. Therefore, the lockup clutch 11 functions as a so-called torque fuse, and accordingly, the opportunity to improve the power transmission efficiency by lowering the belt clamping pressure of the continuously variable transmission mechanism 1 is increased, so that the fuel consumption can be improved.

  The above control example is a control example in which control is uniformly prohibited or terminated when there is a judder occurrence history, but if judder can be avoided, even if there is a judder occurrence history, The above-described control including learning about the engagement pressure of the lockup clutch 11 may be permitted, and the control may be continued without ending. That is, judder in a friction clutch is likely to occur when the engagement pressure is in the vicinity of the lowest engagement pressure within a range where slip does not occur. Once generated, the judder converges to the extent that the engagement pressure slightly changes. There is a tendency not to. On the other hand, when the engagement pressure is not limited to such a delicate engagement pressure but immediately increases or decreases and changes, there is a tendency that judder hardly occurs. Therefore, in the control example shown in FIG. 21 and the control example shown in FIG. 22, if there is a judder occurrence history, the engagement pressure of the lockup clutch 11 is quickly changed to make it difficult to generate judder. In such a case, the start of the control is prohibited and the control is ended.

  The example shown in FIG. 21 is obtained by changing a part of the flowchart shown in FIG. 17 described above, and when it is determined that there is a judder generation history in a state where the determination of steady running is established (step) If the determination in step S126 is affirmative, a request to make the change gradient (sweep gradient) of the hydraulic pressure that sets the engagement pressure of the lockup clutch 11 abrupt is output (step S127). The sweep gradients are the sweep gradients DLPLU1, DLPLU2, and DLPLU3 in the above-described “phase2” to “phase4”. In step S127, a command is output to increase these values.

  Next, it is determined whether judder has occurred even if the change gradient of the hydraulic pressure is increased (step S128). If the determination in step S128 is affirmative, judder is generated in the process of changing the engagement pressure of the lockup clutch 11, and therefore control including learning of the engagement pressure cannot be performed. Therefore, in this case, it is determined that the control start condition is not satisfied, and the process immediately proceeds to step S140 without performing processing such as setting “phase”. That is, control is not started.

  On the other hand, if a negative determination is made in step S128, judder can be avoided by making the engagement pressure sweep gradient steep even if there is a judder generation history. Such a negative determination may be established when, for example, the judder occurrence history is incorrect or when the fluid is replaced with a new one. Therefore, in this case, since the judder occurrence history does not become a hindrance to the start of control, the process proceeds to step S122 described above, and the subsequent control in steps S123 to S125 is described with reference to FIG. 15 or FIG. To run.

  Therefore, in the case where the control shown in FIG. 21 is executed, if there is a judder occurrence history and the judder can be avoided, the control including the learning of the engagement pressure of the lockup clutch 11 is started. As a result, the opportunity to execute control for making the so-called margin of the transmission torque for slipping smaller than the so-called margin of the transmission torque for slipping in the continuously variable transmission mechanism 1 increases, so that the power transmission efficiency in the continuously variable transmission mechanism 1 increases. To improve fuel efficiency.

  On the other hand, as one of the control end conditions, it is determined whether or not judder occurs even when the hydraulic sweep gradient is steep. An example of this is shown in FIG. 22, and if it is determined in step S151 described above that the steady running is being determined, the judder may be caused even if the hydraulic sweep gradient is made steep based on the control in step S127 described above. It is determined whether or not it occurs (step S156). If the determination in step S156 is affirmative, there is a judder generation history and the generation of judder cannot be avoided. In this case, the control end condition is satisfied and the process immediately goes to step S730. Advancing and processing for control termination are performed.

  On the other hand, if a negative determination is made in step S156, judder can be avoided, so the process proceeds to step S152, and the subsequent control in steps S153 to S154 will be described with reference to FIG. 16 or FIG. Run as you did. Note that such a negative determination may be established when, for example, the judder occurrence history is incorrect or when the fluid is replaced with a new one.

  Therefore, if the judder occurrence history is not satisfied, the control termination condition is not satisfied, and if the judder can be avoided, the control including the learning of the engagement pressure of the lockup clutch 11 is continued. As a result, the opportunity to execute control for making the so-called margin of the transmission torque for slipping smaller than the so-called margin of the transmission torque for slipping in the continuously variable transmission mechanism 1 increases, so that the power transmission efficiency in the continuously variable transmission mechanism 1 is increased. Higher fuel consumption can be improved.

Here, briefly explaining the relationship between the present invention and the above embodiment, the functional means of Step S150 is equivalent to the end detection means of the present invention, step S683, step S684, step S686, step S750 functional means, it corresponds to the engagement-pressure increase means of the present invention.

  In the above-described specific example, the lock-up clutch arranged in series on the input side of the continuously variable transmission mechanism has been described as an example. Therefore, the clutch may be a clutch arranged in series in the transmission direction, and may be a clutch disposed on the output side of the continuously variable transmission mechanism, or may be a clutch other than the lock-up clutch. The continuously variable transmission mechanism is not limited to the belt type, and may be a traction type continuously variable transmission mechanism. In the above specific example, the oil temperature and the degree of deterioration (period of use) are cited as factors for changing the friction coefficient of the clutch. However, other physical quantities related to the friction coefficient in the present invention are used as appropriate. can do. Further, in the above specific example, the difference between the engagement pressure obtained by applying a predetermined margin pressure to the engagement pressure with zero slip and the engagement pressure output based on the input torque at that time is used as the learning value. However, the learning value of the engagement pressure in the present invention may be an engagement pressure when the clutch is re-engaged or an engagement pressure obtained by applying a predetermined margin pressure thereto. Furthermore, in the above-described specific example, when the learning value is biased, the clamping pressure of the continuously variable transmission mechanism is increased and corrected. However, in the present invention, when it is detected that the learning value bias has decreased. Further, the increase-corrected clamping pressure may be reduced.

It is a figure which shows a part of flowchart for demonstrating an example of control by the control apparatus of this invention. It is a figure which shows the part following FIG. 1 of the flowchart for demonstrating an example of control by the control apparatus of this invention. It is a figure which shows the part following FIG. 2 of the flowchart for demonstrating an example of control by the control apparatus of this invention. It is a figure which shows the part following FIG. 3 of the flowchart for demonstrating an example of control by the control apparatus of this invention. It is a figure which shows the part following FIG. 4 of the flowchart for demonstrating an example of control by the control apparatus of this invention. It is a figure which shows the part following FIG. 5 of the flowchart for demonstrating an example of control by the control apparatus of this invention. 6 is a time chart showing changes in the rotation speeds of the input side and output side of the lockup clutch, changes in the engagement hydraulic pressure of the lockup clutch, and changes in the belt clamping pressure when the control according to the present invention is executed. It is a flowchart for demonstrating the other example of control by the control apparatus of this invention, Comprising: It is a figure which shows the flowchart which changed a part of FIG. It is a flowchart for demonstrating other examples of control by the control apparatus of this invention, Comprising: It is a figure which shows the flowchart which changed a part of FIG. FIG. 10 is a time chart when control is executed by a routine including the flowcharts shown in FIGS. 8 and 9. FIG. It is a diagram which shows notionally the characteristic of the friction coefficient of a clutch. It is a diagram which shows notionally the characteristic of the friction coefficient of a clutch by oil temperature. It is a diagram which shows notionally the characteristic of the friction coefficient of a clutch by deterioration. It is a flowchart for demonstrating the other example of control by the control apparatus of this invention, Comprising: It is a figure which shows the flowchart which changed a part of FIG. It is a flowchart which shows an example of the determination routine of the control start condition when oil temperature is used as the control start condition. It is a flowchart which shows an example of the determination routine of the control end condition when oil temperature is used as the control end condition. It is a flowchart which shows an example of the determination routine of the control start condition when the judder generation history and the oil temperature are used as the control start condition. It is a flowchart which shows an example of the determination routine of the control end condition when using the judder generation history and the oil temperature as the control end condition. It is a flowchart which shows the other example of determination routine of the control start condition when the generation | occurrence | production log | history of judder and oil temperature are made into control start conditions. FIG. 12 is a flowchart showing another example of a control end condition determination routine when a judder occurrence history and an oil temperature are used as control end conditions. It is a flowchart which shows the further another example of the determination routine of the control start condition when the generation | occurrence | production history of judder and oil temperature are made into control start conditions. FIG. 12 is a flowchart showing still another routine for determining a control end condition when a judder occurrence history and an oil temperature are used as a control end condition. It is a figure which shows typically the drive system containing the continuously variable transmission mechanism which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Continuously variable transmission mechanism, 3 ... Torque converter, 4 ... Engine (power source), 11 ... Lock-up clutch, 19 ... Drive pulley, 20 ... Driven pulley, 23 ... Belt, 26 ... Drive wheel, 31 ... For transmission Electronic control unit (CVT-ECU).

Claims (2)

After lowering the engagement pressure of the clutch arranged in series with the continuously variable transmission mechanism until slipping occurs from the fully engaged state, the engagement pressure is increased and reengaged. An engagement pressure obtained by adding a predetermined margin pressure to the engagement pressure to be engaged is determined, and the transmission torque margin until slippage occurs in the clutch is set to the margin until slippage occurs in the continuously variable transmission mechanism. A control device for a drive system including a continuously variable transmission mechanism that is set smaller than a margin of transmission torque of the continuously variable transmission mechanism,
An end detection means for detecting that an end condition of control for engaging the clutch with an engagement pressure obtained by applying a predetermined margin pressure to an engagement pressure at which the clutch is re-engaged;
If the child earlier Symbol termination condition is satisfied to the end detecting means is detected slip the clutch after detection, the engagement pressure of the clutch after the increased torque capacity of the continuously variable transmission mechanism And an engagement pressure increasing means for increasing the pressure so that the slip does not occur. A drive system control device including a continuously variable transmission mechanism. 2. The continuously variable transmission mechanism according to claim 1, wherein the engagement pressure increasing means is configured to gradually increase the engagement pressure with a predetermined gradient when the clutch is in a slipping state. Including drive system control device.

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