JP6910732B2 - Transmission controller - Google Patents

Description

The present invention relates to a transmission control device.

Conventionally, there is known a transmission mounted on a vehicle and located between a drive source and wheels and having a continuously variable transmission mechanism and a stepped transmission mechanism. Patent Document 1 discloses a control device that shifts a continuously variable transmission mechanism toward a target gear ratio during a gear gear switching operation of the stepped transmission mechanism.

Japanese Unexamined Patent Publication No. 5-10428

In the above-mentioned conventional control device, if the shift phase of the stepped transmission mechanism does not reach the inertia phase when the shift of the continuously variable transmission is completed, the change of the gear ratio of the transmission becomes discontinuous and the driving force is increased. There was a risk that the changes would be discontinuous. The present invention has been made in view of such technical problems, and an object of the present invention is to provide a transmission control device capable of suppressing discontinuous changes in driving force.

In the transmission control device according to the embodiment of the present invention, when the stepless transmission mechanism and the stepped transmission mechanism are changed to achieve the target gear ratio of the transmission, after the inertia phase of the stepped transmission mechanism is started. The speed change of the stepless speed change mechanism is controlled so that the speed change of the stepless speed change mechanism is completed.

By controlling the shift of the continuously variable transmission so that the shift of the continuously variable transmission ends after the inertia phase of the stepped transmission mechanism starts, the shift ratio of the transmission becomes continuous, so that the driving force It is possible to suppress the discontinuity of the change of.

The schematic configuration of the vehicle drive system of the first embodiment is shown. An example of the shift line diagram of the first embodiment is shown. It is a time chart in the power-off downshift of the first embodiment. It is a time chart in the power-off downshift of the comparative example.

Hereinafter, embodiments 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.

[First Embodiment]
FIG. 1 shows a vehicle drive system of the present embodiment. The drive system has a power train and a shift control unit. The power train consists of an engine (internal combustion engine) 1, a torque converter 2, a reduction mechanism (first gear row) 3, an automatic transmission 4, a final drive gear mechanism (second gear row, final reduction gear) 6, and wheels 7. Have. 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 drive pulley (primary pulley) 8a connected to the output shaft of the reduction mechanism 3 and a driven pulley (secondary pulley) 8b connected to the input shaft 90 of the auxiliary transmission mechanism 9. It is a belt-type continuously variable transmission mechanism in which a belt 8c is hung between them. Hydraulic oil (oil) is supplied to each of the drive pulley 8a and the driven 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 drive pulley 8a and the supply pressure to the driven 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 labinyo type, and the input shaft 90 (driven 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 (first speed selection brake) L / B. The carrier 9b can be driven and coupled to the ring gear 9c via a high clutch (second speed selection clutch) H / C. 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 forward 1st 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 drive pulley 8a and the driven pulley 8b of the continuously variable transmission mechanism 8 (usually only the supply pressure to the drive 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. the number (hereinafter, "engine speed") signals from an engine speed sensor S _E for detecting the N _Eng, input speed of the automatic transmission 4 (hereinafter, "automatic transmission input rotational speed") automatically detecting the N _in 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 shift 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 variable speed 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 of 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.

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. The power-on state is a state in which the torque (hereinafter, “continuously variable transmission side input torque”) T _{p_in} input from the engine 1 side to the automatic transmission 4 (continuously variable transmission mechanism 8) is positive. The power-off state includes a state in which the transmission output shaft 5 is on the drive side and the input shaft 90 is on the driven side, in other words, a state in which the continuously variable transmission side input torque T _{p_in} is negative, and a continuously variable transmission side input torque T. _{Includes the state} where p_in is near zero (whether 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 continuously variable transmission side input torque T p_in} 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 determination 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 determination 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).

Specifically, when the transmission controller 11 determines that the vehicle is in the power-on state when the vehicle speed VSP is greater than a predetermined threshold value VSP * when the vehicle is not stopped (during driving), the transmission controller 11 performs preparatory (shift start) control and then high. The downshift is advanced by controlling the torque capacity of the clutch H / C. After the inertia phase, it becomes the torque phase. In the preparatory control, the low brake L / B is precharged with hydraulic pressure, 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 sub-transmission side increases and the inertia phase progresses. While the inertia phase is in progress, the control of the _flood control supplied to the high clutch H / C suppresses an excessive rise (blowing) of 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 and 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 supply hydraulic pressure 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 performs torque down control from the preparation phase to the end phase during the replacement control of the auxiliary transmission mechanism 9. That is, the torque down request value is output to the engine controller. As a result, the upper limit of the engine torque T _Eng is regulated, and the increase of the _{engine torque T Eng} is regulated so that the response delay of the actual supply hydraulic pressure to the indicated supply hydraulic pressure to the fastening element is out of the permissible range.

Further, the transmission controller 11 cooperates with the shift control of the continuously variable transmission mechanism 8 and the shift control of the auxiliary transmission mechanism 9. The transmission controller 11 determines the transient auxiliary transmission side ratio (hereinafter, “indicating auxiliary transmission side ratio”) i _sub (c) up to the target auxiliary transmission side ratio i _{sub (o) as follows.} First, the shift time of the auxiliary transmission mechanism 9 is determined. The time spent on the preparatory phase is determined based on the rate of decrease in the supply oil pressure to the fastening element on the release side (removal response) and the time until the precharge of the fastening element on the fastening side is completed (shelf pressure is exceeded). 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. In addition, the time spent in the inertia phase (substantial shift time; hereinafter, "secondary shift side shift time") T _sub is set in advance. Time change rate d (i _sub (c)) / dt of the indicated sub-transmission side ratio i _sub (c) and the indicated sub-transmission side ratio i _sub (c) in the inertia phase (in other words, the sub-transmission side input rotation in the inertia phase The number N _{sub_in} profile or target pattern) is determined as follows. As shown in FIG. 3, the rate of change d (i _sub (c)) / dt is set to be trapezoidal in the coordinates (time chart) with time as the horizontal axis. The rate of change d (i _sub (c)) / dt increases with a predetermined gradient in the early phase of the inertia phase, is constant in the metaphase of the inertia phase, and decreases with a predetermined gradient in the late phase of the inertia phase. From this rate of change d (i _sub (c)) / dt, the indicated sub-transmission side ratio i _sub (c) is determined. The indicator sub-transmission side ratio i _sub (c) increases with a gradually increasing gradient in the early phase of the inertia phase, increases with a constant gradient in the middle phase of the inertia phase, and increases with a gradually decreasing gradient in the latter half of the inertia phase. do. It is preferable that the profile of the indicated sub-transmission side ratio i _sub (c) satisfies, for example, the following conditions.
・ 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 transmission controller 11 has a target total ratio i (o) and a target sub-transmission side ratio i _sub (o), and the gear ratio of the target (post-shift) continuously variable transmission mechanism 8 (hereinafter, “target continuously variable transmission”). Shift side ratio ") i _p (o) is calculated, and the transient continuously variable transmission side ratio up to the target continuously variable transmission side ratio i _p (o) (hereinafter," indicated continuously variable transmission side ratio ") i _{Determine p} (c) as follows. As shown in FIG. 3, the coordinate (time chart) to the horizontal axis of time, the instruction time rate of change d of the continuously variable transmission side ratio _{i p (c) (i p} (c)) / dt trapezoidal To set. The rate of change d (i _P (c)) / dt increases with a predetermined gradient in the first half of the shift of the continuously variable transmission mechanism 8 and is constant in the middle half of the shift of the continuously variable transmission mechanism 8. It decreases with a predetermined gradient in the latter half of the shift. The shifting of the continuously variable transmission mechanism 8 (previous term) starts at the same time as the preparation phase of the auxiliary transmission mechanism 9, for example. The latter half of the shift of the continuously variable transmission mechanism 8 overlaps with the first half of the inertia phase of the auxiliary transmission mechanism 9, and preferably coincides with each other. That is, it is preferable that the latter half of the speed change of the continuously variable transmission mechanism 8 starts at the same time as the inertia phase of the auxiliary transmission mechanism 9 (the first half of the period) starts, and ends at the same time as the first half of the inertial phase of the auxiliary transmission mechanism 9 ends.

_{In this way, the time T p} spent for shifting the continuously variable transmission mechanism 8 (hereinafter, “continuously variable transmission side shifting time”) T p is preset. This unapproved shift side shift time T _p is longer than the _{time T pp + tp} obtained by adding the time of the preparation phase and the time of the torque phase of the auxiliary transmission mechanism 9 at the time of power-off downshift, for example _{(T p} > T _{pp). + tp} ). Then, the continuously variable transmission side ratio i _p (c) is determined from the rate of change d (i _{p (c)) / dt.} Instruction continuously variable side ratio i _p (c) is increased by gradually increases gradient year shift of the continuously variable transmission mechanism 8, to increase the medium term at a constant gradient, increasing in gradient gradually decrease late do. That is, the continuously variable transmission mechanism 8 continues to downshift until the end of the shift of the continuously variable transmission mechanism 8 (at least until the start of the inertia phase of the auxiliary transmission mechanism 9) (the continuously variable transmission mechanism 8 does not downshift to the lowest: maximum gear ratio). ) as an indication continuously variable side ratio i _p (c) is set. Assuming a time change of the product of the indicated continuously variable transmission side ratio i _p (c) and the indicated auxiliary transmission side ratio i _sub (c) (instructed total ratio i (c)), it is the shift of the automatic transmission 4. It becomes an S-shaped profile that increases with a gradient that gradually increases in the first half, increases with a substantially constant gradient in the middle term, increases with a gradient that gradually decreases in the second half, and then reaches the target total ratio i (o).

In the inertia phase of the auxiliary transmission mechanism 9, the transmission controller 11 has a torque capacity of the fastening elements on the release side and the fastening side of the auxiliary transmission mechanism 9 so as to realize the above profile _{of the indicated auxiliary transmission side ratio i sub (c).} (Instructed torque capacity) is obtained, and the supply oil pressure to the fastening element on the release side and the instruction supply hydraulic pressure to the fastening element on the fastening side are set so as to realize these indicated torque capacities. The transmission controller 11 obtains the indicated torque capacity as an added value of the F / F indicated capacitance, which is the operation amount of feedforward control, and the F / B indicated capacitance, which is the operation amount of feedback control. The F / F indicated capacitance is calculated based _{on the input torque T sub_in on the sub transmission side.} The F / B indicated capacitance is calculated based _{on the input rotation speed N sub_in on the auxiliary transmission side.} 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. Further, the transmission controller 11 is instructed to realize the profile of the continuously variable transmission side ratio i _p (c), controls the supply pressure and the pressure supplied to the driven pulley 8b to the drive pulley 8a.

Next, the action and effect will be described. When the target total ratio i (o) is achieved by coordinating the shift control of the continuously variable transmission mechanism 8 and the shift control of the auxiliary transmission mechanism 9, when the continuously variable transmission mechanism 8 finishes shifting, the auxiliary transmission mechanism 9 If the inertia phase of is not started, the change of the total ratio i may be discontinuous, and the change of the driving force of the vehicle may be discontinuous. Hereinafter, a comparative example will be described. The transmission controller of the comparative example determines the indicated total ratio i (c) of the automatic transmission 4 from the target total ratio i (o) determined from the transmission diagram and the predetermined speed change speed. The indicated sub transmission side ratio i _sub (c) is obtained in the same manner as the transmission controller 11 of the present embodiment. On the other hand, by dividing the indicated total ratio i (c) by the indicated sub-transmission side ratio i _sub (c), the indicated continuously variable transmission side ratio i _p (c) is obtained. In such a comparative example, the end timing of the shift of the continuously variable transmission mechanism 8 is not particularly related to the start timing of the inertia phase of the auxiliary transmission mechanism 9. Therefore, the shift of the continuously variable transmission mechanism 8 can be completed before the start of the inertia phase of the auxiliary transmission mechanism 9. For example, when the automatic transmission 4 is downshifted, if the downshift of the continuously variable transmission mechanism 8 stops at the lowest ratio and then the downshift of the auxiliary transmission mechanism 9 starts, the engine brake generated becomes discontinuous. _{In particular, in the power-off downshift in which the input torque T p_in} on the continuously variable transmission side is equal to or less than the judgment value T _{p_in} *, the downshift is advanced by supplying hydraulic pressure to the low brake L / B, so that the torque phase is changed after the preparation phase. , The start of the inertia phase may be delayed. Therefore, the shift of the continuously variable transmission mechanism 8 is likely to be completed before the start of the inertia phase of the auxiliary transmission mechanism 9. In particular, when the driver switches the select lever from the D range to the L range in order to obtain engine braking force and a downshift request is issued, a rapid large shift of the automatic transmission 4 is commanded. Therefore, there is a high possibility that the continuously variable transmission mechanism 8 will reach the lowest position before the downshift of the auxiliary transmission mechanism 9 starts.

FIG. 4 shows a time chart in a power-off downshift by a transmission controller of a comparative example. G indicates the acceleration of the vehicle (including deceleration by engine braking). The phase indicates each phase of the transmission of the auxiliary transmission mechanism 9. T _LB indicates the F / F indicated capacity of the low brake L / B, and T _HC indicates the F / F indicated capacity of the high clutch H / C. Times t41 to t42 are the preparation phase, times t42 to t43 are the torque phase, times t43 to t44 are the inertia phase, and times t44 to t45 are the end phases. The continuously variable transmission side ratio i _p reaches the lowest position before the change of the auxiliary transmission side ratio i _sub starts (immediately after time t42). In other words, the continuously variable transmission mechanism 8 ends the shift. After that, the downshift (inertia phase) of the auxiliary transmission mechanism 9 starts at time t43. Therefore, the change in the gear ratio (total ratio i) of the automatic transmission 4 as a whole becomes discontinuous, so that the deceleration G fluctuates (near time t42) and the driving force (engine brake) changes (shock). ) May be felt by the driver. Further, in the comparative example, the continuously variable transmission side ratio i _p (c) is set so that the total with the instruction sub transmission side ratio i _sub (c) is the total ratio i. _{Therefore, once the sub-} transmission side ratio i sub (instructed sub-transmission side ratio i _sub (c)) reaches a certain size or more, the continuously variable transmission side ratio i _p (instructed continuously variable transmission side ratio) once reaches the lowest position. i _p (c)) _{decreases as the sub-} transmission side ratio i sub (instructed sub-transmission side ratio i _sub (c)) increases (before time t44). That is, the continuously variable transmission mechanism 8 upshifts. _{Therefore, fluctuations in} the automatic transmission input rotation speed N in (rotation speed of the turbine runner 2a of the torque converter 2) may occur, and a shock (feeling of being pushed out) may occur due to this rotation fluctuation (inner shuttlek) (time t44). (Indicated by the change in G immediately before). In particular, when the continuously variable transmission mechanism 8 switches from the low side to the upshift, the tracking of the actual continuously variable transmission side ratio i _{p with respect to the indicated continuously variable transmission side ratio i p} (c) tends to be delayed. For this reason, the timing of the change of the auxiliary transmission side ratio i _sub and the timing of the change of the continuously variable transmission side ratio i _p are deviated, and the total ratio i (automatic transmission input rotation speed N _in ) fluctuates, causing a shock. Cheap.

On the other hand, the transmission controller 11 of the present embodiment controls the shift of the continuously variable transmission mechanism 8 so that the shift of the continuously variable transmission mechanism 8 ends after the inertia phase of the auxiliary transmission mechanism 9 starts. Therefore, the change of the total ratio i becomes continuous, and the change of the driving force of the vehicle becomes continuous. For example, when the automatic transmission 4 is downshifted, the downshift of the auxiliary transmission mechanism 9 is started before the downshift of the continuously variable transmission mechanism 8 is stopped, so that the generated engine brake (deceleration G due to) becomes continuous. .. Even during a power-off downshift in which the start of the inertia phase of the auxiliary transmission mechanism 9 is likely to be delayed, the shift of the continuously variable transmission mechanism 8 can be terminated after the start of the inertia phase of the auxiliary transmission mechanism 9.

FIG. 3 shows a time chart in the power-off downshift by the transmission controller 11 of the present embodiment. Times t31 to t32 are the preparation phase, times t32 to t33 are the torque phase, times t33 to t34 are the inertia phase, and times t34 to t35 are the end phases. The continuously variable transmission side ratio i _p ends the change at time 331 after the time t 33 when the change of the _sub transmission side ratio i sub starts. Therefore, the fluctuation (shock) of the deceleration G is suppressed by the continuous change of the total ratio i (near time t33). Since the downshift of the continuously variable transmission mechanism 8 and the downshift of the auxiliary transmission mechanism 9 are continuously performed, the feeling of time lag and the feeling of two steps of the engine brake are suppressed (time t31 to t34). From the viewpoint of promoting the progress of the gear shift (suppresses stagnation of shifting), the change of the continuously variable transmission side ratio i _p is preferably completed before the first half of the inertia phase of the subtransmission mechanism 9.

The target continuously variable transmission side ratio i _p (o) is calculated from the target total ratio i (o) and the target sub transmission side ratio i _sub (o). During shifting, the continuously variable transmission side ratio i _p is controlled to be equal to or less than the target continuously variable transmission side ratio i _p (o) (shift ratio after shifting of the continuously variable transmission mechanism 8). Therefore, it is suppressed that the continuously variable transmission side ratio i _p exceeds the target continuously variable transmission side ratio i _p (o) and reaches the maximum gear ratio before the change of the auxiliary transmission side ratio i _{sub starts.} In the example shown in FIG. 3, for example, even when a downshift by the operation from the D range to the L range, the continuously variable side ratio i _p reaches the uppermost row is suppressed. Therefore, the change of the total ratio i becomes more reliable and continuous. In addition, as in the comparative example (before time t44 in FIG. 4), the continuously variable transmission side ratio i _p (instructed continuously variable transmission side ratio i _p (c)) may change from the lowest to decrease (upshift). Since this is avoided, it is also possible to prevent the _{timing of change between the sub-} shift side ratio i sub and the continuously variable transmission side ratio i _p from shifting (the total ratio i fluctuates).

但し、d(i_P）/dtは無段変速側レシオi_Pの時間変化率、d(i_sub）/dtは副変速側レシオi_subの時間変化率を示す。 Furthermore, during the period in which the time change rate d (i _P ) / dt of the continuously variable transmission side ratio i _p decreases (time t33 to t331), the time change rate d (i _sub ) / dt _{of the auxiliary transmission side ratio i sub is} It overlaps with the increasing period (time t33 to t331). By superimposing the latter half of the shift of the continuously variable transmission mechanism 8 and the first half of the shift (inertia phase) of the auxiliary transmission mechanism 9 (matching the timings of both phases) in this way, the fluctuation of the _{automatic transmission input rotation speed N in} Shock is suppressed. That is, the automatic transmission input rotation speed N _in is given by the product of the automatic transmission output rotation speed N _out , the continuously variable transmission side ratio i _p, and the auxiliary transmission side ratio i _sub. Considering that the change in the automatic transmission output rotation speed N _out is sufficiently small, the rate of change d (N _in ) / dt of the automatic transmission input rotation speed N _in is given by the following equation (1).

However, d (i _P ) / dt indicates the time change rate of the continuously variable transmission side ratio i _P , and d (i _sub ) / dt indicates the time change rate of the auxiliary transmission side ratio i _sub.

As can be seen from the above equation (1), the rate of change d (N _{in ) / dt of the automatic transmission input rotation speed N in} is the term of the rate of change d (i _P ) / dt of the continuously variable transmission side ratio i _P. , The rate of change of the auxiliary transmission side ratio i _sub is added to the term _{d (i sub) / dt.} For example, when the automatic transmission 4 is downshifted, the _{deceleration G due to the increase in} the automatic transmission input speed N in (due to the engine brake) is the rate of change d (N _in ) / dt ( _{d) of the automatic transmission input speed N in.} It is determined by the inertia torque), which is the product of the moment of inertia of the rotating element. If the fluctuation of the rate of change d (N _in ) / dt is small, the fluctuation of the deceleration G is also small. Therefore, as described above, the period of decrease in the rate of change d (i _{P ) / dt of the continuously variable transmission side ratio i p and} the period of increase of the rate of change d (i _{sub ) / dt of the ratio i sub on the auxiliary transmission side overlap.} Since the fluctuation of the rate of change d (N _{in ) / dt of the automatic transmission input speed N in} , which is the sum of the terms of both rate of change, is suppressed, the fluctuation of the deceleration G due to the inertia shuttle is also suppressed. (Times t33 to t331). The period of decrease in the rate of change d (i _P ) / dt (the latter half of the shift of the continuously variable transmission mechanism 8) and the _{period of the increase period of the rate of change d (i sub} ) / dt (the first half of the inertia phase of the auxiliary transmission mechanism 9) It suffices if they overlap even a part of each other. In this embodiment, both periods preferably coincide. That is, instruction continuously variable side ratio i _p as the end point of the start point and both periods of both periods coincide respectively (c) is set. Therefore, the above-mentioned action and effect can be improved. It should be noted that only one of the start point and the end point of both periods may match.

As described above, the first embodiment has the following effects.
(1) The transmission controller 11 (control device) of the automatic transmission 4 (transmission).
Automatic transmission 4
Located between engine 1 (vehicle drive source) and wheels 7
The continuously variable transmission mechanism 8 that can change the gear ratio steplessly,
Sub-transmission mechanism 9 (stepped transmission mechanism) that can change the gear ratio step by step by switching between engagement and release of low brake L / B, high clutch H / C and reverse brake R / B (multiple fastening elements) And have
When the transmission controller 11 shifts the continuously variable transmission mechanism 8 and the auxiliary transmission mechanism 9 to achieve the target total ratio i (o) (target transmission ratio) of the automatic transmission 4, the inertia phase of the auxiliary transmission mechanism 9 is set. The speed change of the stepless speed change mechanism 8 is controlled so that the speed change of the stepless speed change mechanism 8 ends after the start.
Therefore, the change in the total ratio i becomes continuous, and the change in the driving force of the vehicle becomes continuous, so that the driver's discomfort can be suppressed.

(2) Power on when the torque input from the engine 1 (drive source) side to the automatic transmission 4 (continuously variable transmission side input torque T _{p_in} ) is greater than the predetermined power-on judgment value T _{p_in} * (threshold value). When the power-off state is the state in which the _{input torque T p_in} on the continuously variable transmission side is equal to or less than the power-on judgment value T _{p_in *.}
When the transmission controller 11 (control device) downshifts the automatic transmission 4 in the power-off state, the shifting of the continuously variable transmission mechanism 8 ends after the inertia phase of the auxiliary transmission mechanism 9 (stepped transmission mechanism) starts. The speed change of the continuously variable transmission mechanism 8 is controlled so as to be performed.
Therefore, even during a power-off downshift in which the start of the inertia phase of the auxiliary transmission mechanism 9 is likely to be delayed, the shift of the continuously variable transmission mechanism 8 can be terminated after the start of the inertia phase of the auxiliary transmission mechanism 9.

(3) the transmission controller 11 (controller) during the shifting, the target continuously variable side ratio i _p (o) (target gear ratio of the continuously variable transmission mechanism 8: gear ratio after the shift) follows so as to, controlling the gear ratio of the continuously variable transmission mechanism 8 (continuously variable side ratio i _p).
Therefore, it is suppressed that the continuously variable transmission side ratio i _p exceeds the target continuously variable transmission side ratio i _p (o) and reaches the maximum gear ratio before the change of the auxiliary transmission side ratio i _{sub starts, so that the total ratio is suppressed.} The change of i can be made more reliable and continuous.

_{(4) In the transmission controller 11 (control device), the period during which the rate of change d (i P} ) / dt of the speed change ratio of the continuously variable transmission mechanism 8 decreases at the end of the speed change of the continuously variable transmission mechanism 8 is the auxiliary speed change. The shift of the continuously variable transmission mechanism 8 is controlled so as to overlap with the period in which the _{rate of change d (i sub} ) / dt of the gear ratio of the auxiliary transmission mechanism 9 increases at the start of the shift of the mechanism 9 (stepped transmission mechanism). ..
Therefore, the shock due to the fluctuation of the inertia torque (automatic transmission input speed N _{in) can be suppressed.}

Although the embodiment for carrying out the present invention has been described above based on the embodiment, the specific configuration of the present invention is not limited to the configuration shown in the embodiment 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) or the like may be used.

1 engine (drive source)
4 Automatic transmission (transmission)
7 Wheels 8 Continuously variable transmission mechanism 9 Sub-transmission mechanism (stepped transmission mechanism)
11 Transmission controller (control device)
L / B low brake (fastening element)
H / C high clutch (fastening element)
R / B reverse brake (fastening element)

Claims (3)

It ’s a transmission control device,
The transmission is
Between the vehicle drive source and the wheels,
A continuously variable transmission mechanism that can change the gear ratio steplessly,
It has a stepped transmission mechanism that can change the gear ratio step by step by switching between fastening and releasing of multiple fastening elements.
The control device shifts the continuously variable transmission mechanism and the stepped transmission mechanism to achieve the target gear ratio of the transmission , and after the inertia phase of the stepped transmission mechanism has started, and has the above. The speed change of the stepless speed change mechanism is controlled so that the speed change of the stepless speed change mechanism is completed before the speed change mechanism finishes the shift.
Transmission control device. In the transmission control device according to claim 1,
A power-on state is a state in which the torque input from the drive source side to the transmission is greater than a predetermined threshold value, and a power-off state is a state in which the torque input to the transmission from the drive source side is equal to or less than the threshold value. When it comes to state
When the transmission is downshifted in the power-off state, the control device performs the continuously variable transmission after the inertia phase of the stepped transmission mechanism has started and before the stepped transmission mechanism finishes shifting. The speed change of the continuously variable transmission mechanism is controlled so that the speed change of the speed change mechanism is completed.
A transmission control device characterized by the fact that. In the transmission control device according to claim 1 or 2.
In the control device, the period during which the rate of change of the gear ratio of the stepless transmission mechanism decreases at the end of the shift of the stepless transmission mechanism is the period during which the shift of the stepless transmission mechanism starts. A control device for a transmission, characterized in that the speed change of the stepless speed change mechanism is controlled so as to overlap with a period in which the rate of change of the gear ratio increases.

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