JP2019190567A - Lock-up control device for automatic transmission - Google Patents

Abstract

To prevent shock accompanied with a drawn pulling of a lock-up clutch even if a vehicle speed is decreased in the case of scene showing a probability in which the vehicle speed is decreased after a vehicle speed is increased.SOLUTION: A lock-up control device for a belt-type variable transmission CVT comprises a torque converter 2, a lock-up clutch 20 and a lock-up control part 80. The lock-up control part 80 for performing a lock-up control under application of a lock-up schedule LU/S comprises a lock-up fastening control part 80a for performing a control action to be moved to a lock-up fastened state upon completion of a changing-over condition during running operation in which the lock-up clutch 20 is released. When a steering speed caused by a steering operation is more than a steering speed threshold value A, the lock-up fastening control part 80a determines that the changing-over condition is not established irrespective of a transition of operating state to LU ON region to keep the lock-up clutch 20 in its released state.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a lockup control device for an automatic transmission mounted on a vehicle.

  2. Description of the Related Art Conventionally, a lock-up clutch control device has been known in which protection control is executed based on the transmission torque of the lock-up clutch. In this conventional apparatus, the first estimated value of the transmission torque of the lockup clutch is calculated based on the command value given to the electromagnetic control valve, and the second estimated value of the transmission torque is calculated based on the output torque of the drive source. Then, any one of the calculated transmission torques is selected, and based on this, protection control for preventing the temperature rise of the friction material of the lockup clutch is executed (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2015-68385

  In the conventional apparatus, the lockup clutch is switched between the released state and the engaged state according to the vehicle speed and the accelerator opening. Therefore, when accelerating, for example, when exiting the parking lot from the parking lot, it is assumed that the vehicle speed is once lowered by exceeding the step. For this reason, there is a problem that the lock-up clutch may be peeled off due to a decrease in the vehicle speed during the transition of the lock-up clutch from the released state to the engaged state due to acceleration, which may cause a shock that fluctuates the vehicle longitudinal acceleration. there were.

  The present invention has been made paying attention to the above problems, and it is an object of the present invention to prevent a shock associated with the release of the lock-up clutch even when the vehicle speed decreases in a scene where the vehicle speed may decrease after the vehicle speed increases. And

In order to achieve the above object, a lockup control device for an automatic transmission according to the present invention includes a torque converter, a lockup clutch, and a lockup control unit.
The lockup control unit controls the engagement / slip / release of the lockup clutch using a lockup schedule that divides the lockup engagement region and the lockup release region according to the operation state.
The lockup control unit is provided with a lockup engagement control unit that performs control to shift to the lockup engagement state when a predetermined switching condition is satisfied during traveling with the lockup clutch released.
When the steering speed by the steering operation is equal to or higher than a predetermined value, the lockup engagement control unit does not satisfy the switching condition regardless of the transition to the lockup engagement region of the driving state, and keeps the lockup clutch in the released state.

  In this way, if the steering speed is higher than the predetermined value, it is regarded as a scene where the vehicle speed may decrease. It is possible to prevent a shock associated with the peeling of the film.

1 is an overall system diagram showing a drive system and a control system of an engine vehicle to which a lockup control device for an automatic transmission according to a first embodiment is applied. It is a shift schedule figure which shows an example of the D range continuously variable transmission schedule used when the continuously variable transmission control in automatic transmission mode is performed by a variator. It is a schematic block diagram which shows the lockup control apparatus of Example 1. FIG. It is a lockup schedule figure which shows an example of the lockup schedule set to the lockup control part of the CVT control unit. It is a flowchart which shows the flow of the lockup fastening control process performed in the lockup fastening control part which has in a lockup control part. 5 is a time chart showing characteristics of accelerator opening, steering amount, steering speed, vehicle speed, and LU determination in a scene where the vehicle speed decreases after the vehicle speed increases.

  Hereinafter, a mode for carrying out a lockup control device for an automatic transmission according to the present invention will be described based on a first embodiment shown in the drawings.

  The lockup control device according to the first embodiment is applied to an engine vehicle equipped with a belt-type continuously variable transmission (an example of an automatic transmission) including a torque converter, a forward / reverse switching mechanism, a variator, and a final reduction mechanism. is there. Hereinafter, the configuration of the first embodiment will be described by being divided into “entire system configuration”, “lockup control device configuration”, and “lockup fastening control processing configuration”.

[Overall system configuration]
FIG. 1 shows a drive system and a control system of an engine vehicle to which a lockup control device for an automatic transmission according to a first embodiment is applied. The overall system configuration will be described below with reference to FIG.

As shown in FIG. 1, the drive system of the engine vehicle includes an engine 1, a torque converter 2, a forward / reverse switching mechanism 3, a variator 4, a final reduction mechanism 5, and drive wheels 6 and 6. Yes.
Here, the belt type continuously variable transmission CVT is configured by incorporating the torque converter 2, the forward / reverse switching mechanism 3, the variator 4, and the final reduction mechanism 5 in a transmission case (not shown).

  The engine 1 can control the output torque by an engine control signal from the outside, in addition to the output torque control by the accelerator operation by the driver. The engine 1 includes an output torque control actuator 10 that performs torque control by a throttle valve opening / closing operation, a fuel cut operation, and the like. For example, fuel cut control is executed during coasting by an accelerator release operation.

  The torque converter 2 is a starting element by a fluid coupling having a torque amplification function and a torque fluctuation absorption function. When the torque amplifying function and the torque fluctuation absorbing function are not required, the lockup clutch 20 that can directly connect the engine output shaft 11 (= torque converter input shaft) and the torque converter output shaft 21 is provided. The torque converter 2 includes a pump impeller 23, a turbine runner 24, and a stator 26 as constituent elements. The pump impeller 23 is connected to the engine output shaft 11 via the converter housing 22. The turbine runner 24 is connected to the torque converter output shaft 21. The stator 26 is provided in the transmission case via the one-way clutch 25.

  The forward / reverse switching mechanism 3 is a mechanism that switches the input rotation direction to the variator 4 between a forward rotation direction during forward travel and a reverse rotation direction during reverse travel. The forward / reverse switching mechanism 3 includes a double pinion planetary gear 30, a forward clutch 31 using a plurality of clutch plates, and a reverse brake 32 using a plurality of brake plates. The forward clutch 31 is hydraulically engaged by the forward clutch pressure Pfc when a forward travel range such as the D range is selected. The reverse brake 32 is hydraulically engaged by the reverse brake pressure Prb when the reverse travel range such as the R range is selected. The forward clutch 31 and the reverse brake 32 are both released by draining the forward clutch pressure Pfc and the reverse brake pressure Prb when the N range (neutral range) is selected.

  The variator 4 has a primary pulley 42, a secondary pulley 43, and a pulley belt 44, and continuously changes the transmission gear ratio (ratio of variator input rotation to variator output rotation) by changing the belt contact diameter. A gear shifting function is provided. The primary pulley 42 includes a fixed pulley 42 a and a slide pulley 42 b arranged on the same axis as the variator input shaft 40, and the slide pulley 42 b is slid by the primary pressure Ppri guided to the primary pressure chamber 45. The secondary pulley 43 includes a fixed pulley 43 a and a slide pulley 43 b that are arranged coaxially with the variator output shaft 41, and the slide pulley 43 b is slid by the secondary pressure Psec guided to the secondary pressure chamber 46. The pulley belt 44 is stretched around a sheave surface that forms a V shape of the primary pulley 42 and a sheave surface that forms a V shape of the secondary pulley 43. The pulley belt 44 is formed of two sets of laminated rings in which a large number of annular rings are stacked from the inside to the outside and a plurality of punched plate members, and is attached by being laminated in an annular manner by being sandwiched along the two sets of laminated rings. It is composed of elements. The pulley belt 44 may be a chain-type belt in which a large number of chain elements arranged in the pulley traveling direction are coupled by pins penetrating in the pulley axial direction.

  The final deceleration mechanism 5 is a mechanism that decelerates the variator output rotation from the variator output shaft 41 and transmits it to the left and right drive wheels 6 and 6 while providing a differential function. The final speed reduction mechanism 5 is a speed reduction gear mechanism that includes an output gear 52 provided on the variator output shaft 41, an idler gear 53 and a reduction gear 54 provided on the idler shaft 50, and a final gear provided on the outer peripheral position of the differential case. And a gear 55. The differential gear mechanism includes a differential gear 56 interposed between the left and right drive shafts 51, 51.

  As shown in FIG. 1, the engine vehicle control system includes a hydraulic control unit 7, a CVT control unit 8, and an engine control unit 9. The CVT control unit 8 and the engine control unit 9 which are electronic control systems are connected by a CAN communication line 13 which can exchange information with each other.

  The hydraulic control unit 7 adjusts the primary pressure Ppri to the primary pressure chamber 45, the secondary pressure Psec to the secondary pressure chamber 46, the forward clutch pressure Pfc to the forward clutch 31, and the reverse brake pressure Prb to the reverse brake 32. In addition, it is a unit that regulates the lockup differential pressure Plu to the lockup clutch 20. The hydraulic control unit 7 includes an oil pump 70 that is rotationally driven by the engine 1 that is a travel drive source, and a hydraulic control circuit 71 that adjusts various control pressures based on the discharge pressure from the oil pump 70. . The hydraulic control circuit 71 includes a line pressure solenoid valve 72, a primary pressure solenoid valve 73, a secondary pressure solenoid valve 74, a select solenoid valve 75, and a lockup differential pressure solenoid valve 76. Each solenoid valve 72, 73, 74, 75, 76 performs a pressure adjustment operation according to a control command value (indicated current) output from the CVT control unit 8.

  The line pressure solenoid valve 72 adjusts the discharge pressure from the oil pump 70 to the commanded line pressure PL in accordance with the line pressure command value output from the CVT control unit 8. The line pressure PL is a source pressure when adjusting various control pressures, and is a hydraulic pressure that suppresses belt slip and clutch slip against torque transmitted through the drive system.

  The primary pressure solenoid valve 73 adjusts the pressure to the primary pressure Ppri commanded using the line pressure PL as the original pressure in accordance with the primary pressure command value output from the CVT control unit 8. The secondary pressure solenoid valve 74 adjusts the pressure to the secondary pressure Psec commanded using the line pressure PL as the original pressure in accordance with the secondary pressure command value output from the CVT control unit 8.

  The select solenoid valve 75 adjusts the pressure to the forward clutch pressure Pfc or the reverse brake pressure Prb commanded using the line pressure PL as the original pressure according to the forward clutch pressure command value or the reverse brake pressure command value output from the CVT control unit 8. To do.

  The lock-up differential pressure solenoid valve 76 adjusts the lock-up differential pressure Plu for engaging / slipping / releasing the lock-up clutch 20 according to the command current Alu output from the CVT control unit 8.

The CVT control unit 8 performs line pressure control, shift control, forward / reverse switching control, lockup control, and the like. In the line pressure control, a command value for obtaining a target line pressure corresponding to the accelerator opening is output to the line pressure solenoid valve 72. In the shift control, when the target gear ratio (target primary rotation Npri ^* ) is determined, a command value for obtaining the determined target gear ratio (target primary rotation Npri ^* ) is output to the primary pressure solenoid valve 73 and the secondary pressure solenoid valve 74. In the forward / reverse switching control, a command value for controlling the engagement / release of the forward clutch 31 and the reverse brake 32 is output to the select solenoid valve 75 according to the selected range position. In the lockup control, the command current Alu for controlling the lockup differential pressure Plu for engaging / slipping / releasing the lockup clutch 20 is output to the lockup differential pressure solenoid valve 76.

  Information from the primary rotation sensor 90, the vehicle speed sensor 91, the secondary pressure sensor 92, the oil temperature sensor 93, the inhibitor switch 94, the brake switch 95, the turbine rotation sensor 96, and the like is input to the CVT control unit 8. Further, information from the secondary rotation sensor 97, the primary pressure sensor 98, the steering angle sensor 99, and the like is input.

  Sensor information from the engine rotation sensor 12, the accelerator opening sensor 14, and the like is input to the engine control unit 9. When the CVT control unit 8 requests the engine control information and the accelerator opening information to the engine control unit 9, the CVT control unit 8 receives information on the engine speed Ne and the accelerator opening APO via the CAN communication line 13. Further, when requesting engine torque information to the engine control unit 9, information on the actual engine torque Te estimated in the engine control unit 9 is received via the CAN communication line 13.

  FIG. 2 shows an example of the D range continuously variable transmission schedule used when the variator 4 executes the continuously variable transmission control in the automatic transmission mode when the D range is selected.

The “D range shift mode” is an automatic shift mode in which the gear ratio is automatically changed steplessly in accordance with the vehicle operating state. The shift control in the “D range shift mode” is performed by operating points on the D range continuously variable shift schedule of FIG. 2 specified by the vehicle speed VSP (vehicle speed sensor 91) and the accelerator opening APO (accelerator opening sensor 14) ( VSP, APO) determines the target primary rotational speed Npri ^* . Then, the actual primary rotational speed Npri from the primary rotational sensor 90 is performed by the pulley hydraulic pressure feedback control that matches the target primary rotational speed Npri ^* .

That is, as shown in FIG. 2, the D range continuously variable transmission schedule used in the “D range speed change mode” has a gear ratio range of the lowest gear ratio and the highest gear ratio according to the operating point (VSP, APO). Within the range, the gear ratio is set to change steplessly. For example, when the vehicle speed VSP is constant, when the accelerator is depressed, the target primary speed Npri ^* increases and shifts in the downshift direction, and when the accelerator return operation is performed, the target primary speed Npri ^* decreases and increases. Shift in the shift direction. When the accelerator opening APO is constant, the vehicle shifts in the upshift direction when the vehicle speed VSP increases, and the vehicle shifts in the downshift direction when the vehicle speed VSP decreases.

[Configuration of lock-up control device]
FIG. 3 shows the lockup control device of the first embodiment. FIG. 4 shows an example of a lockup schedule set in the lockup control unit 80. Hereinafter, the schematic configuration of the lockup control device will be described with reference to FIGS. 3 and 4. Lock-up is abbreviated as “LU”.

  As shown in FIG. 3, the drive system to which the lockup control device is applied includes an engine 1 (driving drive source), a torque converter 2 having a lockup clutch 20, a forward / reverse switching mechanism 3, and a variator 4 ( A continuously variable transmission mechanism), a final reduction mechanism 5, and a drive wheel 6. The engine 1 drives an oil pump 70. The forward / reverse switching mechanism 3 includes a forward clutch 31 and a reverse brake 32.

  As shown in FIG. 3, the control system to which the lockup control device is applied includes a CVT control unit 8, an engine control unit 9, and a lockup differential pressure solenoid valve 76. The CVT control unit 8 inputs the vehicle speed VSP from the vehicle speed sensor 91, the turbine rotation speed Nt from the turbine rotation sensor 96, the steering angle θ from the steering angle sensor 99, and the like. The engine control unit 9 inputs the engine rotation speed Ne from the engine rotation sensor 12 and the accelerator opening APO from the accelerator opening sensor 14. The CVT control unit 8 and the engine control unit 9 are connected via a CAN communication line 13 so that information can be exchanged.

The CVT control unit 8 includes a lockup control unit 80 that controls the engagement / slip / release of the lockup clutch 20 using a lockup schedule LU / S that divides the lockup engagement region and the lockup release region according to the operating state. Is provided.
Here, the “driving state” refers to a driving point specified by the vehicle speed VSP and the accelerator opening APO.

  As shown in FIG. 4, the lock-up schedule LU / S is set in the lock-up control unit 80, drawn on the two-dimensional coordinate plane by the vehicle speed VSP and the accelerator opening APO, and the LU ON line (lock-up fastening line) LU OFF line (lock-up release line).

  When the lock-up clutch 20 is in the released state, the LU ON line divides the LU OFF area (lock-up release area) indicated by hatching in FIG. 4 from the LU ON area (lock-up engagement area). The LU ON line uses the second vehicle speed VSP2 as the LU start vehicle speed when the accelerator opening APO is equal to or smaller than the second accelerator opening APO2. In the region where the accelerator opening APO is from the second accelerator opening APO2 to the third accelerator opening APO3, the vehicle speed gradually increased from the second vehicle speed VSP2 is set as the LU start vehicle speed. In a region where the accelerator opening APO is equal to or greater than the third accelerator opening APO3, the third vehicle speed VSP3 is set as the LU start vehicle speed.

  The LU OFF line divides the LU ON area (lock-up engagement area) and the LU OFF area (lock-up release area) when the lock-up clutch 20 is engaged. The LU OFF line uses the first vehicle speed VSP1 as the LU release vehicle speed regardless of the accelerator opening APO. Note that VSP1 <VSP2 <VSP3.

  The lockup control unit 80 includes a lockup fastening control unit 80a and a lockup release control unit 80b. The lockup engagement control unit 80a performs control to shift to the lockup engagement state when the switching condition is satisfied during the traveling with the lockup clutch 20 in the released state. The lockup release control unit 80b performs control to shift to the lockup release state when a predetermined switching condition is satisfied during traveling with the lockup clutch 20 engaged.

  The first embodiment is characterized by a control processing configuration in the lockup fastening control unit 80a. That is, if the steering speed by the steering operation is equal to or higher than the steering speed threshold A, the switching condition is not satisfied regardless of the transition of the driving point (VSP, APO) to the LU ON region, and the lockup clutch 20 is maintained in the released state.

[Lock-up fastening control processing configuration]
FIG. 5 shows a flow of the lockup fastening control process executed by the lockup fastening control unit 80a included in the lockup control unit 80. Hereinafter, each step of FIG. 5 will be described. This process is repeatedly performed in a predetermined control cycle.

  In step S1, following the start, it is determined whether or not the operating point (VSP, APO) on the lockup schedule LU / S in FIG. 4 is in the LU OFF region. If YES (exists in the LU OFF area), the process proceeds to step S2. If NO (exists in the LU ON area), the process proceeds to step S5.

  In step S2, following the determination that the vehicle is in the LU OFF region in step S1, the operating point (VSP, APO) on the lockup schedule LU / S in FIG. It is determined whether or not the transition to the ON area is made. If YES (transition to the LU ON area), the process proceeds to step S3, and if NO (the LU OFF area remains), the process proceeds to step S5.

  In step S3, following the determination of transition to the LU ON region in step S2 or the determination in step S4 that the vehicle speed is smaller than the LU ON vehicle speed, it is determined whether or not the steering speed is less than the steering speed threshold A. to decide. If YES (steer speed <steer speed threshold A), the process proceeds to step S4. If NO (steer speed ≧ steer speed threshold A), the determination in step S3 is repeated.

  Here, the “steer speed” is obtained by time differentiation calculation (= dθ / dt) of the steering angle θ acquired from the steering angle sensor 99. The “steer speed threshold A” is a judgment threshold that may cause the vehicle speed VSP, which has risen above the LU ON vehicle speed of the lockup schedule LU / S, to fall below the LU ON vehicle speed due to steering operation intervention such as overcoming a step. Set to.

  In step S4, following the determination that steer speed <steer speed threshold A in step S3, it is determined whether or not the vehicle speed VSP at that time is equal to or higher than the LU ON vehicle speed. If YES (vehicle speed ≧ LU ON vehicle speed), the process proceeds to step S5. If NO (vehicle speed <LU ON vehicle speed), the process returns to step S3.

  Here, “LU ON vehicle speed” refers to the vehicle speed according to the accelerator opening APO by the LU ON line of the lockup schedule LU / S.

  In step S5, following the determination that the vehicle is present in the LU ON region in step S1 or the determination that the vehicle speed is greater than or equal to the LU ON vehicle speed in step S4, the lockup clutch 20 is engaged and the process proceeds to the end.

  Here, when the lockup clutch 20 has advanced to step S5 in the engaged state, the engaged state of the lockup clutch 20 is maintained. On the other hand, when the lock-up clutch 20 has been released and the process proceeds to step S5, the clutch-engaged state is shifted to the clutch-engaged state through smooth LU control that gradually increases the engagement torque of the lock-up clutch 20.

  In step S6, following the determination in step S2 that the LU OFF region remains, the lockup clutch 20 remains in the released state, and the process proceeds to the end.

  Next, the operation of the first embodiment will be described by dividing it into “lock-up engagement control processing operation” and “lock-up engagement control operation in a scene where steering operation intervenes”.

[Lock-up fastening control processing action]
Hereinafter, the lockup fastening control processing operation will be described based on the flowchart shown in FIG.

  When the operation point (VSP, APO) on the lockup schedule LU / S in FIG. 4 remains in the LU OFF region, the process proceeds from S1 to S2 to S6 to the end in the flowchart of FIG. Therefore, the released state of the lockup clutch 20 is maintained.

  When the operating point (VSP, APO) existing in the LU OFF region on the lock-up schedule LU / S in FIG. 4 transits to the LU ON region, and the steering speed <the steering speed threshold A, the flowchart of FIG. In S1, the process proceeds from S1, S2, S3, S4, S5, and the end. Therefore, engagement of the lock-up clutch 20 that is in the released state is started, and the smooth LU control is passed and the state shifts to the engaged state. That is, the lockup fastening control process according to the lockup schedule LU / S of FIG. 4 is executed.

  If the operating point (VSP, APO) existing in the LU OFF region on the lockup schedule LU / S in FIG. 4 has transitioned to the LU ON region, but the steering speed ≧ the steering speed threshold A, the flowchart of FIG. In S1, the process proceeds from S1 to S2 to S3. Then, while the steering speed is greater than or equal to the steering speed threshold A, the determination in S3 is repeated. That is, regardless of the lockup schedule LU / S in FIG. 4, the disengaged state of the lockup clutch 20 is maintained while the steering speed ≧ the steering speed threshold A.

  Thereafter, when the steer speed decreases and the steer speed is smaller than the steer speed threshold A, the process proceeds from S3 to S4 in the flowchart of FIG. 5, but while it is determined in S4 that the vehicle speed is less than the LU ON vehicle speed, S3 → The process of proceeding to S4 is repeated. That is, even when the steering speed is smaller than the steering speed threshold A, the disengaged state of the lockup clutch 20 is maintained while the vehicle speed is smaller than the LU ON vehicle speed.

  Thereafter, when it is determined in S4 that the vehicle speed is greater than or equal to LU ON, in the flowchart of FIG. 5, the process proceeds from S4 to S5 to the end, the engagement of the lockup clutch 20 is started, and the smooth LU control has elapsed. Transition to the fastening state. That is, after the steer speed is lowered and the steer speed is smaller than the steer speed threshold A, the lockup engagement control process according to the lockup schedule LU / S in FIG. 4 is executed again.

  In this way, when the operating point (VSP, APO) transitions from the LU OFF region to the LU ON region on the lockup schedule LU / S, it is determined whether the steering speed is less than the steering speed threshold A. While the steering speed is equal to or higher than the steering speed threshold A, the LU prohibition section is set and the lockup clutch 20 is kept in the released state. When the steering speed becomes less than the steering speed threshold A and the vehicle speed VSP exceeds the LU ON vehicle speed of the lockup schedule LU / S, the switching condition is established, and the lockup clutch 20 is shifted from the released state to the engaged state. Smooth LU control is started.

[Lock-up fastening control action in scenes where steering operation intervenes]
First, during traveling with the lock-up clutch released, the lock-up clutch starts to be engaged when the vehicle speed becomes equal to or higher than the LU ON vehicle speed (for example, about 10 km / h). A comparative example is one in which release of the lock-up clutch is started when the vehicle speed becomes equal to or lower than the LU OFF vehicle speed (for example, about 8 km / h) during traveling with the lock-up clutch engaged.

  When steering operation is performed while accelerating from the parking lot to the roadway, an example is taken of a scene in which the vehicle speed is once lowered by crossing a step. In this scene, as indicated by the broken line characteristic of LU determination in FIG. 6, when the vehicle speed becomes higher than the LU ON vehicle speed at time t1 with acceleration, the lockup clutch is changed from the released state to the engaged state. However, when the vehicle speed drops below the LU OFF vehicle speed at time t2 during the transition to the engaged state, the locked-up clutch in the engaged state is pulled as shown by the broken line characteristics surrounded by the arrow B in FIG. It is released to peel off and a shock occurs. That is, the torque ratio of the torque converter exceeds 1 when the lock-up clutch is released, and the torque ratio of the torque converter becomes 1 when the lock-up clutch is engaged. Therefore, the torque transmitted to the drive wheels is suddenly decreased by the engagement after the transition from release → engagement → release in a short time interval of time t1 to t2, and then the vehicle longitudinal acceleration is changed by the release.

  The present inventors pay attention to the above problem, and if the steering speed by the steering operation is equal to or higher than the steering speed threshold A, the switching condition is not satisfied regardless of the transition to the LU ON region of the driving point (VSP, APO), A configuration that keeps the lock-up clutch 20 in a released state is adopted.

  In other words, lockup engagement control is basically performed using the lockup schedule LU / S, but if the steering operation condition is added to the switching condition and the steering speed is equal to or higher than the steering speed threshold A, the vehicle speed may drop once. I thought it was a scene. The reason for this is that when a steering operation is performed while accelerating when going out from the parking lot and a step is exceeded, the vehicle speed drops due to the step resistance once as shown in the vehicle speed characteristic of FIG. Looking at the steering speed in the area where the vehicle speed falls, it is because the steering speed is equal to or higher than the steering speed threshold A by the steering turning operation. And if it is regarded as a scene in which the vehicle speed may drop, the lock-up clutch 20 that shifts to the engaged state when the control is based on the lock-up schedule LU / S remains in the released state without shifting to the engaged state. I tried to keep it.

  As a result, in a scene where there is a possibility that the vehicle speed decreases after the vehicle speed increases, even if the vehicle speed VSP decreases, it is possible to prevent a shock caused by the lock-up clutch 20 being peeled off. Hereinafter, the lock-up fastening control action in a scene where the steering operation intervenes will be described based on the time chart shown in FIG.

  When the operating point (VSP, APO) transitions from the LU OFF area to the LU ON area on the lockup schedule LU / S at time t1 in FIG. 6, it is determined whether the steering speed is less than the steering speed threshold A. The At time t1, since the steering speed is equal to or higher than the steering speed threshold A, time t1 is set as the start time of the LU prohibited section, and time t3 when the steering speed becomes less than the steering speed threshold A is set as the end time of the LU prohibited section.

  Therefore, in the comparative example, the time t1 to t2 is the lockup clutch engagement section, whereas in the first embodiment, the time t1 to t3 is the LU prohibition section and the lockup clutch 20 is kept in the released state. Is done.

  Thereafter, when the steering speed becomes less than the steering speed threshold A and the time t4 when the vehicle speed VSP becomes equal to or higher than the LU ON vehicle speed of the lockup schedule LU / S, the switching condition is satisfied. Therefore, the smooth LU control for shifting the lockup clutch 20 from the released state to the engaged state is started from time t4.

  As described above, in the lock-up control device for the belt-type continuously variable transmission CVT according to the first embodiment, the following effects can be obtained.

(1) The torque converter 2, the lockup clutch 20, and the lockup control unit 80 are provided.
The torque converter 2 is interposed between the travel drive source (engine 1) and the speed change mechanism (variator 4).
The lock-up clutch 20 is provided in the torque converter 2 and directly connects the torque converter input shaft and the torque converter output shaft by fastening.
The lock-up control unit 80 controls the engagement / slip / release of the lock-up clutch 20 according to the operation state. The lock-up schedule LU / divides the lock-up engagement region (LU ON region) and the lock-up release region (LU OFF region). Use S.
The lock-up control unit 80 is provided with a lock-up engagement control unit 80a that performs control to shift to the lock-up engagement state when the switching condition is satisfied during traveling with the lock-up clutch 20 in the released state.
When the steering speed by the steering operation is equal to or higher than a predetermined value (steer speed threshold A), the lock-up engagement control unit 80a determines that the switching condition is not satisfied regardless of the transition to the lock-up engagement area (LU ON area). The lock-up clutch 20 is kept in the released state.
Thus, when the steer speed is equal to or higher than a predetermined value (steer speed threshold A), it is regarded as a scene in which the vehicle speed may drop once. As a result, in a scene where there is a possibility that the vehicle speed decreases after the vehicle speed increases, even if the vehicle speed VSP decreases, it is possible to prevent a shock caused by the lock-up clutch 20 being peeled off.

(2) The lockup engagement control unit 80a determines that the steering speed is higher than a predetermined value (steer speed threshold A) above the lockup start vehicle speed (LU ON vehicle speed) of the lockup schedule LU / S. It is set to a determination threshold value that may be lowered to the lockup start vehicle speed or less due to the intervention.
As described above, the steering speed is set to a predetermined threshold (steer speed threshold A) as a determination threshold that may reduce the vehicle speed due to the intervention of the steering operation. As a result, it is possible to accurately determine a scene where the vehicle speed may decrease after the vehicle speed increases, and to keep the lockup clutch 20 in the released state.

(3) When the operation state transitions from the lock-up release area (LU OFF area) to the lock-up engagement area (LU ON area), the lock-up engagement control unit 80a has a steering speed less than a predetermined value (steer speed threshold A). It is determined whether or not.
While the steering speed is equal to or higher than a predetermined value (steer speed threshold A), the lockup engagement prohibition section is set, and the lockup clutch 20 is kept in the released state.
Thus, while the steering speed is equal to or higher than the predetermined value (the steering speed threshold A), the lockup engagement prohibition section is set. As a result, in a scene where the vehicle speed decreases after the vehicle speed increases, it is possible to reliably prevent a shock associated with the lock-up clutch 20 being peeled off.

(4) The lockup engagement control unit 80a maintains the lockup clutch 20 in the released state, and then the steer speed becomes less than a predetermined value (steer speed threshold A) and the vehicle speed VSP is equal to the lockup schedule LU / S. When the vehicle speed becomes equal to or higher than the lockup start vehicle speed (LU ON vehicle speed), the switching condition is established, and control for shifting the lockup clutch 20 from the released state to the engaged state is started.
As described above, after the lockup clutch 20 is kept in the released state, the switching is performed when the steering speed becomes less than the predetermined value (steering speed threshold A) and the vehicle speed VSP becomes equal to or higher than the lockup starting vehicle speed (LU ON vehicle speed). The condition is established. As a result, in a scene where the vehicle speed decreases after the vehicle speed increases, the lockup clutch 20 can be shifted to the engaged state at an appropriate timing based on the lockup schedule LU / S after passing the lockup engagement prohibition section.

(5) The speed change mechanism is a continuously variable speed change mechanism (variator 4) that changes the speed ratio to steplessly.
The lockup engagement control unit 80a is drawn on a two-dimensional coordinate plane based on the vehicle speed VSP and the accelerator opening APO. When the lockup clutch 20 is in the released state, the lockup release region (LU OFF region) and the lockup engagement region ( A lockup schedule LU / S having a lockup fastening line (LU ON line) that separates the LU ON area) is set.
In this way, the continuously variable transmission mechanism (variator 4) is mounted, and a lockup schedule LU / S having a lockup fastening line (LU ON line) based on the vehicle speed VSP and the accelerator opening APO is set. As a result, in a vehicle equipped with a continuously variable transmission mechanism (variator 4), it is possible to respond to steering operation intervention immediately after starting, and the lockup start vehicle speed (LU ON vehicle speed) depends not only on the vehicle speed VSP but also on the accelerator opening APO. Can be set appropriately.
In other words, in the case of the continuously variable transmission mechanism (variator 4), unlike the automatic transmission with a stepped shift stage in which the shift shock is a problem, a large vehicle speed range immediately after the start is LU ON from the viewpoint of improving fuel efficiency. The lockup schedule LU / S to be set as the area is set. And by setting the lockup start vehicle speed (LU ON vehicle speed) to the high vehicle speed side (third vehicle speed VSP3) in the region where the accelerator opening APO is high, by delaying the lockup start when there is an acceleration request, The torque amplification function of the torque converter 2 can be used effectively.

  The automatic transmission lockup control device of the present invention has been described based on the first embodiment. However, the specific configuration is not limited to the first embodiment, and design changes and additions are allowed without departing from the spirit of the invention according to each claim of the claims.

  In the first embodiment, as the lock-up engagement control unit 80a, an example in which it is determined whether or not the steering speed is less than the steering speed threshold A when the operation state transitions from the LU OFF area to the LU ON area. However, the lockup engagement control unit may be an example of determining whether the steering speed is less than the steering speed threshold A when the operation state is in the LU OFF region.

  In the first embodiment, as the lockup engagement control unit 80a, the lockup engagement prohibition section is set while the steering speed is equal to or higher than the steering speed threshold A, and the lockup clutch 20 is kept in the released state. . However, the lockup engagement control unit may be an example in which all sections where the steering speed is equal to or higher than the steering speed threshold A when the operation state is in the LU OFF region are set as lockup engagement prohibition sections.

  In the first embodiment, the lock-up engagement control unit 80a determines that the switching condition is satisfied when the steering speed is less than the steering speed threshold A and the vehicle speed VSP is equal to or higher than the LU ON vehicle speed of the lock-up schedule LU / S. The example which starts the control which transfers the clutch 20 from a releasing state to a fastening state was shown. However, as the lockup engagement control unit, when the steering speed becomes less than the steering speed threshold, or immediately after a predetermined time has elapsed, the switching condition is established and the lockup clutch is shifted from the released state to the engaged state. It may be an example of starting.

  In the first embodiment, an example in which the lockup control device of the present invention is applied to an engine vehicle equipped with a belt type continuously variable transmission CVT as an automatic transmission is shown. However, the lock-up control device of the present invention may be applied to a vehicle equipped with a stepped transmission called step AT or a vehicle equipped with a continuously variable transmission with a sub-transmission as an automatic transmission. Further, the applied vehicle is not limited to an engine vehicle, and can be applied to a hybrid vehicle in which an engine and a motor are mounted on a traveling drive source, an electric vehicle in which a motor is mounted on a traveling drive source, and the like.

1 Engine (driving drive source)
CVT belt type continuously variable transmission (automatic transmission)
2 Torque converter 20 Lock-up clutch 3 Forward / reverse switching mechanism 4 Variator (continuously variable transmission mechanism)
5 Final Deceleration Mechanism 6 Drive Wheel 7 Hydraulic Control Unit 76 Lockup Differential Pressure Solenoid Valve 8 CVT Control Unit 80 Lockup Control Unit 80a Lockup Fastening Control Unit 80b Lockup Release Control Unit 9 Engine Control Unit 12 Engine Rotation Sensor 14 Accelerator Open Degree sensor 91 Vehicle speed sensor 96 Turbine rotation sensor 99 Steering angle sensor
LU / S lockup schedule

Claims (5)

A torque converter interposed between the traveling drive source and the speed change mechanism;
A lock-up clutch that is provided in the torque converter and that directly connects the torque converter input shaft and the torque converter output shaft by fastening;
A lockup control unit that controls the engagement / slip / release of the lockup clutch using a lockup schedule that divides the lockup engagement region and the lockup release region according to an operation state, and
The lockup control unit is provided with a lockup fastening control unit that performs control to shift to a lockup fastening state when a switching condition is satisfied during traveling in which the lockup clutch is in a released state,
The lockup engagement control unit determines that the switching condition is not satisfied regardless of the transition to the lockup engagement region of the driving state when the steering speed by the steering operation is equal to or higher than a predetermined value, and sets the lockup clutch in the released state. A lockup control device for an automatic transmission, characterized by maintaining. In the automatic transmission lockup control device according to claim 1,
The lock-up engagement control unit may reduce the vehicle speed that has increased the predetermined value of the steering speed to a value equal to or higher than the lock-up start vehicle speed of the lock-up schedule to a value equal to or lower than the lock-up start vehicle speed due to a steering operation intervention. A lockup control device for an automatic transmission, characterized by being set to a certain threshold value. In the automatic transmission lockup control device according to claim 1 or 2,
The lockup engagement control unit determines whether the steering speed is less than a predetermined value when the operating state transitions from a lockup release region to a lockup engagement region,
While the steering speed is equal to or higher than a predetermined value, a lockup engagement prohibition section is set, and the lockup clutch is kept in a released state. In the automatic transmission lockup control device according to claim 3,
The lockup engagement control unit maintains the switching condition when the steering speed is less than a predetermined value after the lockup clutch is released and the vehicle speed is equal to or higher than the lockup start vehicle speed of the lockup schedule. A lockup control device for an automatic transmission that is established and starts control for shifting the lockup clutch from a released state to an engaged state. In the automatic transmission lockup control device according to any one of claims 1 to 4,
The speed change mechanism is a continuously variable speed change mechanism that changes the speed ratio steplessly.
The lockup engagement control unit is drawn on a two-dimensional coordinate plane based on a vehicle speed and an accelerator opening, and a lockup engagement line that divides a lockup release region and a lockup engagement region when the lockup clutch is in a released state. A lockup control device for an automatic transmission, characterized by setting a lockup schedule.