JP6960537B2 - Control device and control method for automatic transmission - Google Patents

Description

The present invention relates to a control device and a control method for an automatic transmission.

Conventionally, as an automatic transmission mounted on a vehicle, a transmission equipped with a variator and a stepped transmission mechanism between an input shaft on the drive source side and an output shaft on the wheel side is known. Patent Document 1 discloses a technique for increasing the torque input from the drive source side at the time of the inertia phase in which the fastening element is changed to advance the shift at the time of downshift in the auxiliary transmission mechanism.

However, in the above-mentioned conventional control device, the inertia phase time is not managed, and if the inertia phase time becomes long when the torque input from the drive source side to the input shaft is large, judder vibration or shift delay may occur. At the same time, there is a problem that the amount of heat generated by the clutch is large. On the other hand, if the inertia phase time is shortened in order to suppress heat generation, there is a risk of causing a pull G-shock.
The present invention has been made in view of such technical problems, and the inertia phase time does not become long when the input torque is large, and the pulling G shock can be suppressed even when the input torque is small. It is an object of the present invention to provide a control device for an automatic transmission.

WO2014 / 061601

In the present invention, it is provided between the input shaft on the drive source side of the vehicle and the output shaft on the wheel side, and the fastening capacity of the first fastening element is lowered to release it from the fastening state, and the fastening capacity of the second fastening element is released. During the inertia phase of the stepped speed change mechanism that shifts gears by raising the speed from the released state to the fastened state, it is decided to restrict the reduction of the fastened capacity of the first fastening element to less than a predetermined capacity.

That is, when the input torque is large, the fastening capacity of the first fastening element does not become less than the predetermined capacity, so that the inertia phase time does not become long, while when the input torque is small, the first fastening element does not become smaller. Since the reduction of the fastening capacity to less than the predetermined capacity is regulated, the inertia phase time can be lengthened and the pulling G-shock can be suppressed.

The schematic configuration of the vehicle drive system of the Example is shown. An example of the shift line diagram of the embodiment is shown. The state transition at the time of the replacement shift of the auxiliary transmission mechanism of the embodiment is shown. It is a flowchart which determines the instruction capacity of the low brake of an Example. Transmission controller 11 of the embodiment, a flow chart for determining the F / F indicated capacity T _HC of the high clutch H / C in the inertia phase. It is the schematic which shows the base shift profile calculation process of an Example. It is a time chart which _shows the relationship between the calculated auxiliary transmission side input torque of an Example, and the indicated capacity THC of a high clutch H / C. It is a time chart which shows the setting process of the high clutch lowering allowable capacity of an Example. It is a time chart which shows the high clutch indicated capacity after the limit of an Example. It is the schematic which shows the shift | shift profile after the limit of an Example.

Hereinafter, examples of the present invention will be described with reference to the drawings. In the following description, the "gear ratio" of a certain transmission mechanism is a value obtained by dividing the input rotation speed of the transmission mechanism by the output rotation speed of the transmission mechanism.

FIG. 1 shows a vehicle drive system of this embodiment. The drive system has a power train and a shift control unit. The power train includes an engine 1, a torque converter 2, a reduction mechanism 3, an automatic transmission 4, a final drive gear mechanism 6, and wheels 7. Engine 1 is the drive source for the vehicle. The torque converter 2 has a lockup clutch 20 and is drive-coupled (connects the driving force so as to be transmitted) to the engine 1. The automatic transmission 4 is driven and coupled to the torque converter 2 via the reduction mechanism 3. The final drive gear mechanism 6 is driven and coupled to the automatic transmission 4 via the transmission output shaft (propeller shaft) 5. The power from the automatic transmission 4 is output to the wheels 7 via the final drive gear mechanism 6.

The automatic transmission 4 has a continuously variable transmission mechanism 8 and an auxiliary transmission mechanism 9. The continuously variable transmission mechanism 8 has a primary pulley 8a connected to the output shaft of the reduction mechanism 3 and a secondary pulley 8b connected to the input shaft 90 of the auxiliary transmission mechanism 9, and a belt 8c is hung between them. It is a belt-type continuously variable transmission mechanism that was handed over. Hydraulic oil (oil) is supplied to each of the primary pulley 8a and the secondary pulley 8b, and the pulley width can be freely changed according to the oil pressure thereof. The continuously variable transmission mechanism 8 can change the gear ratio (pulley ratio) steplessly by controlling the supply pressure to the primary pulley 8a and the supply pressure to the secondary pulley 8b.

The auxiliary transmission mechanism 9 is a stepped transmission mechanism having a plurality of friction fastening elements and a planetary gear mechanism. The planetary gear mechanism is a labigno type, and the input shaft 90 (secondary pulley 8b) is driven and coupled to the composite sun gear 9a to input the sun gear 9a. The carrier 9b is output by driving and coupling the carrier 9b to the transmission output shaft 5. The sun gear 9a can be fixed to the case C via the low brake L / B (second fastening element). The carrier 9b can be drive-coupled to the ring gear 9c via the high clutch H / C (first fastening element). The ring gear 9c can be fixed to the case C via the reverse brake R / B.

The low brake L / B, the high clutch H / C, and the reverse brake R / B are wet friction fastening elements, and oil is supplied to each of them, and the fastening and releasing can be freely performed according to the oil pressure. The auxiliary transmission mechanism 9 can select forward 1st speed, forward 2nd speed, and reverse speed by controlling the supply pressure to each fastening element. When selecting the first forward speed, the low brake L / B is engaged and the high clutch H / C and the reverse brake R / B are released. When selecting the forward 2nd speed, the high clutch H / C is engaged and the low brake L / B and the reverse brake R / B are released. In the case of reverse selection, the reverse brake R / B is engaged and the low brake L / B and high clutch H / C are released.

The shift control unit is a control unit for controlling the shift of the automatic transmission 4, and includes a hydraulic control valve unit 10 and a transmission controller 11. A plurality of solenoid valves are built in the hydraulic control valve unit 10. By switching the operating state (on / off) of these solenoid valves, the supply pressure to the primary pulley 8a and secondary pulley 8b of the continuously variable transmission mechanism 8 (usually only the supply pressure to the primary pulley 8a) is controlled. NS. As a result, the gear ratio is changed steplessly. Similarly, by switching the operating state of the solenoid valve, the supply pressure to the low brake L / B, the high clutch H / C, and the reverse brake R / B of the auxiliary transmission mechanism 9 is controlled. As a result, 1st forward speed or 2nd forward speed is selected. Further, the supply pressure to the lockup clutch 20 is controlled by switching the operating state of the solenoid valve. As a result, the engagement state (engagement and release) of the lockup clutch 20 is changed.

The transmission controller 11 controls the operating state of a plurality of solenoid valves in the hydraulic control valve unit 10. The transmission controller 11 has a module that functions as a continuously variable transmission control unit 111 and a module that functions as a stepped speed change control unit 112. The continuously variable transmission control unit 111 calculates the target input rotation speed (hereinafter, “target automatic transmission input rotation speed”) N _in (o) of the automatic transmission 4, and this target automatic transmission input rotation speed N based on _in (o), the gear ratio of the continuously variable transmission mechanism 8 (hereinafter, "CVT side ratio") to control the i _p steplessly. The stepped shift control unit 112 calculates the target shift stage (hereinafter, “target auxiliary shift side ratio”) i _sub (o) of the auxiliary transmission mechanism 9, and the auxiliary shift is set to this target auxiliary shift side ratio i _sub (o). Control mechanism 9. The transmission controller 11 executes the speed change control of the continuously variable transmission mechanism 8 and the speed change control of the auxiliary transmission mechanism 9, so that the automatic transmission 4 as a whole has a target gear ratio (hereinafter, “target total ratio”) i. Realize (o). The overall gear ratio of the automatic transmission 4 (hereinafter, "total ratio") i is the continuously variable transmission side ratio i _p multiplied by the gear ratio of the auxiliary transmission mechanism 9 (hereinafter, "sub transmission side ratio") i _sub. Can be obtained.

The transmission controller 11 has, for example, _{a signal from the throttle opening sensor S Th} that detects the throttle opening TVO, a signal from the accelerator pedal opening sensor S _A that detects the accelerator pedal opening APO, and an output rotation of the engine 1. Number (hereinafter, "engine rotation speed") N A signal from the engine rotation sensor S _{E that detects Eng} , automatic transmission 4 input rotation speed (hereinafter, "automatic transmission input rotation speed") N _in is automatically detected. Signal from the transmission input rotation sensor S _I , signal from the automatic transmission output rotation sensor S _{O that detects N out} of the rotation speed of the transmission output shaft 5 (hereinafter, "automatic transmission output rotation speed"), automatic transmission _{The output signal of the oil temperature sensor S Te} that detects the oil temperature of the machine 4 and the output signal of the inhibitor switch S In _h that detects the position of the select lever are input. The vehicle running speed (hereinafter referred to as "vehicle speed") VSP is detected from the automatic transmission output speed N _{out and the gear ratio of the final drive gear mechanism 6.}

Based on these input information, the transmission controller 11 performs shift control of the automatic transmission 4 as follows using the shift diagram illustrated in FIG. The shift line diagram of FIG. 2 is a combination of the shift line of the continuously variable transmission mechanism 8 and the shift line of the auxiliary transmission mechanism 9. On this transmission line diagram, the operating point of the automatic transmission 4 is _{determined based on the vehicle speed VSP and the target automatic transmission input rotation speed N in} (o). The target automatic transmission input speed N _in (o) is obtained according to the vehicle speed VSP and the accelerator pedal opening APO. The slope of the line connecting the operating point and the zero point in the lower left corner of the shift line diagram represents the total ratio i. When the forward 1st speed is selected as the speed change stage of the auxiliary transmission mechanism 9, the variable speed region of the continuously variable transmission mechanism 8 is the region from the 1st speed lowest line to the 1st speed highest Hi line. On the other hand, when the forward 2nd speed is selected as the speed change stage of the auxiliary transmission mechanism 9, the continuously variable transmission region of the continuously variable transmission mechanism 8 is the region from the 2nd speed lowest line to the 2nd speed highest Hi line. Therefore, the area A in FIG. 2 is an area in which shift control is possible only when the shift stage of the auxiliary transmission mechanism 9 is the first forward speed. Further, the B region is an region where shift control is possible when the shift stage of the auxiliary transmission mechanism 9 is the forward 1st speed or the forward 2nd speed. Further, the C region is a region in which shift control is possible only when the shift stage of the auxiliary transmission mechanism 9 is the second forward speed. In this way, the automatic transmission 4 has a continuously variable transmission mechanism 8 capable of steplessly changing the gear ratio (ratio) and an auxiliary transmission mechanism 9 capable of selecting an arbitrary transmission gear from a plurality of transmission gears. By combining with, it is possible to obtain an expanded ratio coverage as compared with the ratio coverage that can be obtained by only one of them.

In the regions A to C in FIG. 2, the continuously variable transmission mechanism 8 controls so _{that the target automatic transmission input rotation speed N in} (o) is achieved according to the operating point (target total ratio i (o)). Will be done. As a result, the gear ratio is continuously controlled steplessly. On the other hand, the transmission line of the auxiliary transmission mechanism 9 has a forward 1st speed region and a forward 1st speed region by a 1 → 2UP line that switches from the forward 1st speed to the forward 2nd speed and a 2 → 1Down line that switches from the forward 2nd speed to the forward 1st speed. The 2nd speed range is decided. For example, when the operating point crosses the 1 → 2UP line from the low vehicle speed side to the high vehicle speed side, the forward 2nd speed is selected. When you cross the 2 → 1Down line from the high vehicle speed side to the low vehicle speed side, the forward 1st speed is selected. Further, for example, when the operating point shifts from the P point in the C region to the Q point in the A region as the position of the select lever is switched from the D range to the L range during traveling, the auxiliary transmission mechanism 9 is moved forward to the second speed. Outputs a request to downshift from forward to 1st gear.
The L range high limiter line indicates the lower limit of the number of revolutions in the L range.

Further, the transmission controller 11 coordinates the shift control of the continuously variable transmission mechanism 8 with the shift control of the auxiliary transmission mechanism 9. From the target total ratio i (o) and the predetermined shifting speed, the transient total ratio (hereinafter, "indicated total ratio") i (c) from the target total ratio i (o) to the target total ratio i (o) is determined. _{Transient sub-} transmission side ratio from the shift time (inertia phase time) of the sub-transmission mechanism 9 set according to the running condition to the target sub-transmission side ratio i sub (o) (hereinafter, "instructed sub-shift" Side ratio ") _{Determine i sub} (c). By dividing the indicated total ratio i (c) by the indicated sub-transmission side ratio i _sub (c), the transient continuously variable transmission side ratio (hereinafter, "instructed continuously variable transmission side ratio") i _p (c) can be obtained. decide.

Hereinafter, the state in which the input shaft 90 of the auxiliary transmission mechanism 9 is on the drive side and the transmission output shaft 5 is on the driven side is referred to as a power-on state, and the other states are referred to as a power-off state. In the power-off state, the transmission output shaft 5 is on the drive side and the input shaft 90 is on the driven side. In other words, the torque input from the engine 1 side to the continuously variable transmission mechanism 8 (hereinafter, "continuously variable transmission side input"). Torque ") Including the state where _{T p_in is negative.} In addition, the power-off state includes a state in which the continuously variable transmission side input torque T _{p_in} is near zero (regardless of positive or negative). In other words, the power-off state means a state in which the input shaft 90 of the auxiliary transmission mechanism 9 is on the non-driving side.
The shift time of the present invention mainly assumes a 2 → 1 downshift in the power-on state, but the overall picture of control will be described with reference to FIGS. 3 and 4. _{The input torque T p_in} on the stepless speed change side can be obtained from the engaged state of the output torque (hereinafter, “engine torque”) T _{Eng of the} engine 1 and the lockup clutch 20 of the torque converter 2. _{If the input torque T p_in} on the continuously variable transmission side is larger than the predetermined power-on judgment value T _{p_in} * (positive value), it can be determined to be in the power-on state, and _{if it is equal to or less than the power-on judgment value T p_in} *, it can be determined to be in the power-off state. The continuously variable transmission side input torque T _{p_in} substantially corresponds to the _{torque (hereinafter, “sub transmission side input torque”) T sub_in} input from the engine 1 side to the auxiliary transmission mechanism 9 (input shaft 90). The sub-transmission side input torque T _{sub_in} is calculated from the continuously variable transmission side input torque T _{p_in} and the continuously variable transmission side ratio i _p, and the power depends on whether or not the sub-transmission side input torque T _{sub_in} is larger than the predetermined determination value. It may be determined whether it is in the on state or the power off state. Further, it may be determined whether the power is on or off depending on whether or not the accelerator pedal is operated (for example, the accelerator opening APO).

When the auxiliary transmission mechanism 9 shifts between the forward 1st speed and the forward 2nd speed, so-called replacement control is performed in which one of the high clutch H / C and the low brake L / B is engaged and the other is released. Hereinafter, a downshift from 2nd forward speed to 1st forward speed will be described as an example. In the downshift, the high clutch H / C switches from the engaged state to the released state, and the low brake L / B switches from the released state to the engaged state. When the transmission controller 11 determines that the power-on state is determined, the transmission controller 11 advances the downshift (power-on downshift) by controlling the supply hydraulic pressure to the high clutch H / C (torque capacity of the high clutch H / C). When it is determined that the power is off, the downshift (poweroff downshift) is advanced by controlling the flood control supplied to the low brake L / B (torque capacity of the low brake L / B).

As shown in the state transition diagram at the time of replacement shift (downshift) in FIG. 3, the transmission controller 11 determines that the vehicle is in the power-on state when the vehicle is not stopped (running) when the vehicle speed VSP is larger than the predetermined threshold value VSP *. Then, after performing the preparation (at the start of shifting) control, the downshift is advanced by controlling the torque capacity of the high clutch H / C. After the inertia phase, it becomes the torque phase. In the preparation control, the low brake L / B is precharged with flood control, and the low brake L / B is made to stand by in the state immediately before the engagement (preparation phase). In the power-on state, even if there is no torque capacity of the low brake L / B, the rotation speed of the input shaft 90 (hereinafter, "secondary transmission side input rotation speed") N _{sub_in} tries to increase due to _{the auxiliary transmission side input torque T p_in.} do. Therefore, only by reducing the torque capacity of the high clutch H / C to some extent, the input rotation speed N _{sub_in} on the auxiliary transmission side increases and the inertia phase progresses. Further, by controlling the torque capacity of the high clutch H / C, the degree of progress of the inertia phase, that is, the inertia phase time can be controlled. While the inertia phase is in progress, the control of the _flood control supplied to the high clutch H / C suppresses an excessive increase (blow-up) in the input rotation speed N sub_in on the auxiliary transmission side. After that, the oil supply to the high clutch H / C (indicated torque capacity) is lowered, the oil supply to the low brake L / B is increased, and the fastening element responsible for torque transmission is changed from the high clutch H / C to the low brake L. Shift to / B (torque phase).

When the transmission controller 11 determines that the power is off during traveling, it performs preparatory control and then advances the downshift by controlling the torque capacity of the low brake L / B. After the torque phase, it becomes the inertia phase. In the power-off state, the auxiliary transmission side input torque T _{sub_in} is small (for example, negative), so simply reducing the torque capacity of the high clutch H / C does not increase (decrease) the _{auxiliary transmission side input rotation speed N sub_in.} try to). Therefore, after the preparatory control, the supply hydraulic pressure to the high clutch H / C (indicated torque capacity) is lowered and the supply hydraulic pressure to the low brake L / B is increased, and the fastening element responsible for torque transmission is the high clutch H / Shift from C to low brake L / B (torque phase). _{After that, by controlling the flood} control supplied to the low brake L / B, the input rotation speed N sub_in on the auxiliary transmission side is increased to advance the inertia phase.

When the vehicle is stopped when the vehicle speed VSP is equal to or less than the threshold value VSP *, the torque phase is established without the inertia phase after the preparatory control. In any of the above cases, end control (control at the end of shift) is performed to end the transition. The transmission controller 11 completely releases the high clutch H / C by setting the oil supply to the high clutch H / C to zero, and increases the oil supply to the low brake L / B to completely engage the low brake L / B. ..

The transmission controller 11 continues the power-off downshift even if it determines that it is in the power-on state during the power-off downshift. That is, even if it is determined that the torque phase in the power-off downshift is in the power-on state, the transition to the inertia phase in the power-on-downshift (transition indicated by the dashed arrow α in FIG. 3) is prohibited. Further, even if it is determined that the power-on state is in the inertia phase in the power-off downshift, the transition to the inertia phase in the power-on-downshift (transition indicated by the dashed arrow β in FIG. 3) is basically prohibited. When it is determined that the power is on during the inertia phase in the power-off downshift, if the progress rate of the inertia phase exceeds a predetermined threshold value (if it is determined that the inertia phase is substantially completed), Transition to the torque phase in the power-on-downshift.

The transmission controller 11 transitions to the power-off downshift when it is determined to be in the power-off state during the inertia phase in the power-on-downshift. For example, immediately after the power-on-downshift is started by depressing the accelerator pedal, the accelerator pedal is depressed by the driver's change mind. In such a case, when the power-off state is determined during the inertia phase in the power-on-downshift, the power-off is performed if the supply hydraulic pressure (indicated torque capacity) to the high clutch H / C is equal to or higher than a predetermined threshold value. Transition to the torque phase in the downshift. On the other hand, if the flood control supplied to the high clutch H / C is less than the above threshold value at the time of the above determination, the transition to the inertia phase in the power-off downshift occurs. At the time of the above determination, if the progress rate of the inertia phase in the power-on-downshift exceeds a predetermined threshold value (if it is determined that the inertia phase is substantially completed), the torque phase in the power-on-downshift is entered. Transition.

When the auxiliary transmission mechanism 9 is replaced, the transmission controller 11 supplies the oil supply to the fastening element on the release side and the oil supply to the fastening element on the fastening side, respectively, with the indicated torque capacity of the fastening element on the release side and the fastening side. It is calculated based on the indicated torque capacity of the fastening element of. In the preparation phase and the torque phase, these indicated torque capacities are obtained as the F / F directed capacities which are the operation amounts of feedforward control, respectively. In the inertia phase, the indicated torque capacity is obtained as the sum of the F / F indicated capacitance and the F / B indicated capacitance, which is the operation amount of the feedback control. The transmission controller 11 calculates the F / F indicated capacitance based on the sub-transmission side input torque T _{sub_in.} The F / B indicated capacitance is calculated based on the sub-transmission side input rotation speed N _{sub_in.} The F / F indicated capacity and the F / B indicated capacity are calculated by triggering the determination of the start / end of each phase. The F / F indicated capacitance may be provided with a correction gain and an offset according to the speed change progress rate of the auxiliary transmission mechanism 9 as compatible elements for correcting the actual pressure response delay of the fastening element. In this case, the correction is applied from the torque phase, and the correction is canceled at the end phase according to the progress rate.

The transmission controller 11 divides the time spent in the preparation phase into the rate of decrease in the supply oil pressure to the fastening element on the release side (removal response) and the time required to complete the precharge of the fastening element on the fastening side (exceeding the shelf pressure). Determine based on. The time spent in the inertia phase is determined based _{on the input torque T sub_in on the auxiliary transmission side.} The time spent in the torque phase is determined based _{on the auxiliary transmission side input torque T sub_in. For example, when the input torque T sub_in} on the sub transmission side is small, the torque phase time is shorter than when it is large. When the auxiliary transmission side input torque T _{sub_in} is equal to or greater than a predetermined value, the transmission controller 11 determines the change gradient d (i _sub (c)) / dt ( _{of the indicated auxiliary transmission side ratio i sub (c) in the inertia phase.} In other words, the profile or target pattern of the auxiliary transmission speed N _{sub_in} in the inertia phase is determined so as to satisfy the following conditions, for example.
・ It can be realized by the instruction supply oil pressure to the fastening element.
-The response delay of the actual flood control to the indicated flood control to the fastening element is within the permissible range.
-Shock due to inertia torque can be suppressed when the fastening elements on the fastening side are completely fastened.
The method of determining the profile of the auxiliary transmission speed N _{sub_in} will be described in detail later.

Hereinafter, the F / F indicated capacitance of the low brake L / B will be referred to as T _LB, and the F / F indicated capacitance of the high clutch H / C will be referred to as T _HC . FIG. 4 shows a flow in which _{the transmission controller 11 determines the F / F indicated capacitance T LB} of the low brake L / B in the inertia phase. In step S1, it is determined whether or not all of the following conditions are satisfied.
_-The input torque T sub_in on the auxiliary transmission side is equal to or less than the predetermined threshold value T _{sub_in *.}
-A request for downshifting of the auxiliary transmission mechanism 9 was output (it was determined that the downshift from 2nd forward speed to 1st forward speed was started). For example, when the position of the select lever is switched from the D range to the L range, the operating point shifts from the P point to the Q point in the shift line diagram of FIG. 2, and the downshift request is output.
-Vehicle speed VSP is larger than the predetermined threshold VSP *.
If all of these conditions are met, the process proceeds to step S2, and if at least one of these conditions is not met, the process proceeds to step S5. In step S2, it is determined whether the lockup clutch 20 of the torque converter 2 is engaged (on state) or released (off state). If it is on, the process proceeds to step S3, and if it is off, the process proceeds to step S4.

ただし、I_Eng+Tbnはエンジン1とトルクコンバータ2のタービンランナ2aとを合わせた慣性モーメント、i_cは減速機構3の変速比（ギア比）、I_Priは無段変速機構8のプライマリプーリ8aの慣性モーメント、I_Secは無段変速機構8のセカンダリプーリ8bの慣性モーメントである。In step S3, the F / F indicated capacitance T _LB of the low brake L / B is calculated by the following formula (1).

However, I _{Eng + Tbn} is the moment of inertia of the combined engine 1 and the turbine runner 2a of the torque converter 2, i _c is the gear ratio (gear ratio) of the reduction mechanism 3, and I _Pri is the primary pulley 8a of the continuously variable transmission 8. The moment of inertia of, I _Sec, is the moment of inertia of the secondary pulley 8b of the continuously variable transmission mechanism 8.

ただし、I_Tbnはトルクコンバータ2のタービンランナ2aの慣性モーメントである。In step S4, the F / F indicated capacitance T _LB of the low brake L / B is calculated by the following formula (2).

However, I _Tbn is the moment of inertia of the turbine runner 2a of the torque converter 2.

The second term on the right side in equations (1) and (2) is the change gradient d (i) of _{the auxiliary transmission side ratio i sub} (c) in which the rotational element on the engine 1 side of the auxiliary transmission mechanism 9 is determined as described above. _{In sub} (c)) / dt (in other words, _{the profile of the sub-transmission side input rotation speed N sub_in} ), the target sub-transmission side ratio i _sub (o) (in other words, the target rotation speed after shifting of the input shaft 90 (hereinafter, " Target sub-transmission side input rotation speed ") N represents the torque to increase toward _{sub_in (o)).} Equation (1) takes into account the moment of inertia of engine 1 (the rotating element in) that functions as a driven rotating element when the lockup clutch 20 is engaged. Here, the "driven rotation element" means an element that is rotationally driven by the torque transmitted from the low brake L / B. On the other hand, in equation (2), the moment of inertia of the engine 1 is not taken into consideration because the engine 1 does not function as a driven rotation element due to the release of the lockup clutch 20.

In the second term on the right side of equations (1) and (2), d (i _sub (c)) / dt × N _out is the angular acceleration of the input shaft 90 of the auxiliary transmission mechanism 9 (the input rotation speed N _{sub_in} on the auxiliary transmission side). The rate of change). The value multiplied by d (i _sub (c)) / dt × N _out corresponds to the moment of inertia of the driven rotating element on the engine 1 side of the auxiliary transmission mechanism 9 converted to the moment of inertia on the input shaft 90. .. _{The moment of inertia I Eng + Tbn of} the engine 1 and the turbine runner 2a of the torque converter 2 combined, and the moment of inertia I _Tbn of the turbine runner 2a are the gear ratio i _c (squared) of the reduction mechanism 3 and the stepless speed change, respectively. By multiplying the side ratio i _p (squared), it is converted to the moment of inertia on the input shaft 90. _{The moment of inertia I Pri} of the primary pulley 8a of the continuously variable transmission mechanism 8 is converted into the moment of inertia on the input shaft 90 by multiplying the _{ratio i p} (squared) on the continuously variable transmission side.

すなわち、F/F指示容量T_LBを、副変速側入力トルクT_{sub_in}相当（すなわちT_{sub_in}に釣り合う値）とする。In step S5, the F / F indicated capacitance T _LB of the low brake L / B is calculated by the following equation (3).

That is, the F / F indicated capacitance T _LB is equivalent to the _{input torque T sub_in} on the auxiliary transmission side (that is, a value _{commensurate with T sub_in).}

_{That is, when the auxiliary transmission side input torque T sub_in} is equal to or less than the threshold value T _{sub_in} * when the auxiliary transmission mechanism 9 is downshifted, the transmission controller 11 sets the F / F indicated capacitance T _LB of the low brake L / B to "secondary". controlled to a value obtained by adding the torque "to raise toward the shift-side input torque T _{Sub_in} corresponds" to "auxiliary transmission side input target rotation speed N _{Sub_in} auxiliary transmission side input rotational speed _N sub_in (o) (formula ( 1) (2)). Therefore, the problems listed below can be suppressed.
_{Problem 1) In the power-off downshift where the input torque T p_in} on the continuously variable transmission side is near zero (the input torque T _{sub_in} on the auxiliary transmission side is below the threshold T _{sub_in} *), the F / F indicated capacitance T _LB in the inertia phase is (secondary). ₍ Equivalent to the input torque T sub_in on the transmission side) Due to the small size, the inertia phase does not start easily, and even if it starts, it progresses only gradually.
Problem 2) The gear ratio of the continuously controlled continuously variable transmission mechanism 8 (continuously variable transmission side ratio i _p ) reaches the lowest before the change of the auxiliary transmission side ratio i _sub starts, and after that, the auxiliary transmission mechanism 9 The downshift (inertia phase) of the automatic transmission 4 does not start easily, and the change in the gear ratio (total ratio i) of the automatic transmission 4 as a whole becomes discontinuous, which causes fluctuations in the deceleration G.
Problem 3) The driver switches the select lever from the D range to the L range in order to obtain the engine braking force, and even when a downshift request is issued by this, the obtained engine braking force (large deceleration G) is obtained. The problem is that the speed is small and the occurrence is slow, and the downshift of the continuously variable transmission mechanism 8 and the downshift of the auxiliary transmission mechanism 9 occur at different times, resulting in a feeling of time lag in engine braking. The problem of giving the driver a sense of discomfort as a two-step feeling.

Next, the F / F indicated capacitance _THC of the high clutch H / C will be described. 5, the transmission controller 11 of the embodiment, a flow chart for determining the F / F indicated capacity T _HC of the high clutch H / C in the inertia phase.
In step S21, the input torque T _{sub_in} on the sub transmission side is calculated.

In step S22, the base shift profile is calculated. FIG. 6 is a schematic view showing the base shift profile calculation process of the embodiment. _{As shown in FIG. 6A} , the base shift profile is a time change locus of the target sub-shift side input rotation speed N sub_in * defined based on a preset set value. FIG. 6 (b) shows the rate of change in the progress of the shift, and FIG. 6 (c) shows the rate of change in the progress of the shift (a state in which 1 is 100% advanced). Let t be the inertia phase time at which the progress of shifting is completed. The progress rate of shifting is determined by the rate of change in progress. The rate of change in progress has the basic shape characteristics of a trapezoid, a set value a1 that sets the gradient when the rate of progress rises, the rate of progress when the rate of progress is constant is 1 / t, and the rate of progress falls. The desired base shift profile is calculated with the set value a2 for setting the gradient of.

尚、ロックアップクラッチ20解放時は、以下の式より算出する。

ただし、I_Tbnはトルクコンバータ2のタービンランナ2aの慣性モーメントである。
図７は、実施例の演算された副変速側入力トルクとハイクラッチH/Cの指示容量T_HCとの関係を表すタイムチャートである。副変速側入力トルクの変化に応じてイナーシャ相をベース変速プロフィールに沿って進行させるために、図７の太い実線で示すようなハイクラッチ指示容量T_HCのプロフィールが演算される。In step S23, it is calculated by the following equation of high clutch H / C F / F indicated volume T _HC (1).

When the lockup clutch 20 is released, it is calculated from the following formula.

However, I _Tbn is the moment of inertia of the turbine runner 2a of the torque converter 2.
FIG. 7 is a time chart showing the relationship between the calculated auxiliary transmission side input torque of the embodiment and the indicated capacitance T _{HC of the high clutch H / C.} Inertia phase in accordance with a change in the auxiliary transmission side input torque in order to proceed along the basic speed profile, profile of the high clutch instruction capacity T _HC as indicated by a thick solid line in FIG. 7 is calculated.

In step S24, the high clutch lowering allowable capacity T _HC under_lim is set. Here, the reason for setting the high clutch lowering allowable capacity T _{HC under_lim will be described. When the high clutch indicated capacitance T HC} is set based on the base shift profile, the auxiliary transmission mechanism 9 operates to complete the inertia phase in a predetermined inertia phase time. At this time, if the auxiliary transmission side input torque T _{sub_in} is large, the auxiliary transmission side input rotation speed N _{sub_in} tends to increase, so that it is not necessary to reduce the high clutch indicated capacity T _HC so much, so the pull G-shock is reduced. At the same time, the response delay until the shift is completed can be shortened. On the other hand, when the sub-transmission side input torque T _{sub_in} is small, the sub-transmission side input rotation speed N _{sub_in} is unlikely to increase, and the calculation is made so as to significantly decrease the high clutch indicated capacitance T _HC. Then, there is a risk of causing a pull G-shock. In addition, there is a limit to the decrease in the high clutch indicated capacity _THC , and it is difficult to advance the inertia phase according to the base shift profile in the first place. Therefore, it was decided to set the _{high clutch lowering allowable capacity T HC} under_lim that does not cause a pull G-shock.

FIG. 8 is a time chart showing the setting process of the high clutch lowering allowable capacity T _{HC under_lim of the embodiment.} Based on the sub-shift side input torque T _{sub_in} at the start timing of replacement, a preset offset amount is subtracted from that value, and that value is set as the high clutch lowering allowable capacity T _HC under_lim.

In step S25, the high clutch indicated capacity T _HC lim after the limit is calculated. Figure 9 is a time chart showing the limit after high clutch instruction capacity T _HC lim embodiment. After the limit, the high clutch indicated capacity T _HC lim is set by the select high of the high clutch indicated capacity T _HC and the high clutch lowering allowable capacity T _{HC under_lim.} Therefore, a value lower than the high clutch lowering allowable capacity T _HC under_lim is not set, and the pull G-shock can be avoided.

In step S26, after the limit, the target sub-transmission side input rotation speed N _{sub_in} * lim is calculated. That is, the base shift profile determines the reference inertia phase time t, and draws the locus of _{the desired target sub-shift side input rotation speed N sub_in * using the set values a1 and a2.} Limiting the high clutch instruction capacity T _HC necessary to draw the trajectory, auxiliary transmission side input rotational speed N _{Sub_in} next different from the target auxiliary transmission side input rotational speed _N sub_in *, to manage the progress of inertia phase It will be difficult. Therefore, the post-limit high clutch indicated capacity T _HC lim is calculated back to calculate the post-limit target sub-shift side input rotation speed N _{sub_in} * lim, and a post-limit shift profile is created.
In step S27, the high clutch indicated capacitance T _HC lim after the limit and the target sub-transmission side input speed N _{sub_in} * lim after the limit are output.

FIG. 10 is a schematic view showing a post-limit shift profile of the embodiment. FIG. 10A shows the relationship between the base shift profile and the high clutch indicated capacitance T _HC when the sub-shift side input torque T _{sub_in is large.} In this case, the high clutch indicated capacity T _HC maintains a higher value than the high clutch indicated capacity T _HC lim after the limit, and the inertia phase can proceed according to the base shift profile.

On the other hand, as shown in FIG. 10B, although the accelerator pedal is immediately depressed, in the case of a low opening, the input torque Tsub_in on the auxiliary transmission side is small, so when trying to advance the inertia phase, a pull G-shock occurs. Invite. Further, as shown in FIG. 10 (c), even if the final auxiliary transmission side input torque Tsub_in is large by slowly depressing the accelerator pedal, the auxiliary transmission side input torque Tsub_in is already large at the start of the replacement shift. May also cause a pulling G-shock. On the other hand, the rate of change in progress is changed because the post-limit high clutch indicated capacity T _HC lim is calculated back to calculate the post-limit target sub-shift side input rotation speed N _{sub_in} * lim and the post-limit shift profile is created. By lengthening the time t of the inertia phase, judder vibration and shift delay are avoided while avoiding the pull G-shock. Incidentally, when the time t of the inertia phase is longer, because the heat generation of the clutch but is concerned, the first place subtransmission side input torque T _{Sub_in} due to small suppressed by the limit after high clutch instruction capacity T _HC lim is performed , The heat generation of the clutch can be suppressed. Further, even if the time t of the inertia phase becomes long, the driver does not demand sudden acceleration in the first place, and does not give the driver a sense of discomfort such as a shift delay.

As described above, in the examples, the following effects are exhibited.
(1) It is provided between the input shaft 90 on the engine 1 (drive source) side of the vehicle and the transmission output shaft 5 on the wheel side to reduce the fastening capacity of the high clutch H / C (first fastening element). During the inertia phase of the auxiliary transmission mechanism 9 (stepped transmission mechanism) that shifts from the engaged state to the released state and by increasing the engagement capacity of the low brake L / B (second fastening element) to the engaged state from the released state. regulates the drop to less than high clutch instruction capacity T _HC of the high clutch lowered allowable capacity T _HC under_lim (predetermined capacity).
That is, when the auxiliary transmission side input torque Tsub_in is large, the high clutch indicated capacity T _HC does not become less than the high clutch lowering allowable capacity T _HC under_lim, so that the inertia phase time t does not become long, while the secondary when transmission side input torque Tsub_in is small, the decrease in the high clutch lowered allowable capacity T _HC than under_lim high clutch instruction capacity T _HC is restricted, it is possible to increase the inertia phase time t, the pull G shock It can be suppressed. When the sub-shift side input torque Tsub_in is small, judder vibration is unlikely to occur, and the driver does not issue a strong acceleration request, so that the shift delay does not cause discomfort. Moreover, since the input torque Tsub_in on the auxiliary transmission side is small, the amount of heat generated by the clutch can be suppressed. On the other hand, when the sub-shift side input torque Tsub_in is large, the inertia phase time can be shortened to suppress judder vibration, avoid shift delay, and suppress clutch heat generation.

(2) The high clutch indicated capacity T _HC at the time of shifting is calculated from the auxiliary shifting side input torque Tsub_in and the shifting profile (preset target rotation speed of the input shaft), and the calculated high clutch indicated capacity T _HC. When is regulated, the sub-shift side input torque T sub_in and the post-limit high clutch indicated capacity T _HC lim after regulation are calculated back to calculate the post-limit target sub-shift side input rotation speed N _{sub_in} * lim. After the limit calculated back, the high clutch indicated capacitance T _HC is controlled based on the target sub-shift side input rotation speed N _{sub_in * lim.}
Therefore, the rate of change in the progress of the shift is changed by the back calculation, and by lengthening the time t of the inertia phase, it is possible to avoid the judder vibration and the shift delay while avoiding the pull G-shock. Incidentally, when the time t of the inertia phase is longer, because the heat generation of the clutch but is concerned, the first place subtransmission side input torque T _{Sub_in} due to small suppressed by the limit after high clutch instruction capacity T _HC lim is performed , The heat generation of the clutch can be suppressed. Further, even if the time t of the inertia phase becomes long, the driver does not demand sudden acceleration in the first place, and does not give the driver a sense of discomfort such as a shift delay.

Although the embodiment for carrying out the present invention has been described above based on the examples, the specific configuration of the present invention is not limited to the configuration shown in the examples and does not deviate from the gist of the invention. Even if there is a design change of the above, it is included in the present invention. For example, the drive source is not limited to an engine (internal combustion engine), and may be an electric motor or the like. The continuously variable transmission mechanism is not limited to the belt type, but may be a power transmission member in which a chain is hung between pulleys, a toroidal type, or a hydraulically driven mechanism, and is electrically driven. There may be something that is done. The auxiliary transmission mechanism (stepped transmission mechanism) may have three or more gears as a forward gear, a normal planetary gear mechanism may be used, or may be composed of a plurality of gear trains having different gear ratios. It may be composed of a plurality of power transmission paths to be formed and a friction fastening element for switching these power transmission paths. In the embodiment, switching from the D range to the L range is illustrated as a select lever operation for the driver to obtain the engine braking force, but switching to the M range (manual mode) may be used.

Claims (3)

It is provided between the input shaft on the drive source side of the vehicle and the output shaft on the wheel side, and reduces the fastening capacity of the first fastening element to release it from the fastening state, and increases the fastening capacity of the second fastening element. It is a control device for an automatic transmission that regulates the reduction of the fastening capacity of the first fastening element to less than a predetermined capacity during the inertia phase of the stepped speed change mechanism that shifts gears from the released state to the fastening state.
The fastening capacity of the first fastening element at the time of shifting is calculated from the torque of the input shaft and the preset target rotation speed of the input shaft.
When the calculated fastening capacity of the first fastening element is regulated, the target input rotation speed of the input shaft is calculated back from the torque of the input shaft and the tightening capacity of the first fastening element after regulation. A control device for an automatic transmission that calculates and controls the fastening capacity of the first fastening element based on the back-calculated target input rotation speed after regulation . It is provided between the input shaft on the drive source side of the vehicle and the output shaft on the wheel side, and reduces the fastening capacity of the first fastening element to release it from the fastening state, and increases the fastening capacity of the second fastening element. It is a control device for an automatic transmission that regulates the reduction of the fastening capacity of the first fastening element to less than a predetermined capacity during the inertia phase of the stepped speed change mechanism that shifts gears from the released state to the fastening state.
The predetermined capacity is set to a value obtained by subtracting a preset offset amount from the torque of the input shaft at the start timing of replacement of the first fastening element and the second fastening element, which is a control device for an automatic transmission. It is provided between the input shaft on the drive source side of the vehicle and the output shaft on the wheel side, and reduces the fastening capacity of the first fastening element to release it from the fastening state, and increases the fastening capacity of the second fastening element. This is a control method for an automatic transmission that regulates the reduction of the fastening capacity of the first fastening element to less than a predetermined capacity during the inertia phase of the stepped speed change mechanism that shifts gears from the released state to the fastening state.
The fastening capacity of the first fastening element at the time of shifting is calculated from the torque of the input shaft and the preset target rotation speed of the input shaft.
When the calculated fastening capacity of the first fastening element is regulated, the target input rotation speed of the input shaft is calculated back from the torque of the input shaft and the tightening capacity of the first fastening element after regulation. A control method for an automatic transmission, which is calculated and controls the fastening capacity of the first fastening element based on the back-calculated target input rotation speed after regulation .

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