JP6644413B2 - Control device for continuously variable transmission - Google Patents

Description

  The present invention relates to a control device for a continuously variable transmission including a variator capable of continuously changing a speed ratio and a stepped subtransmission mechanism provided in series with the variator.

  Conventionally, when a shift is requested, the speed of the subtransmission mechanism is changed so that the speed ratio of the entire transmission (the overall speed ratio achieved by the variator and the subtransmission mechanism, hereinafter referred to as “through speed ratio”) matches a target value. 2. Description of the Related Art There is known a control device for a continuously variable transmission with an auxiliary transmission that performs a “cooperative shift” that controls the speed ratio of a variator in accordance with the ratio (for example, see Patent Document 1).

JP 05-079554 A

By the way, when the target value of the through speed ratio changes to the low side (downshift) in accordance with the depression of the accelerator pedal, even if the change amount of the target through speed ratio is the same, the subtransmission mechanism downshifts. The amount of change in the speed ratio of the variator (the amount of downshift) differs between when the downshift is not performed and when the downshift is not performed.
That is, the speed ratio change amount of the variator when the sub-transmission mechanism does not downshift has a value corresponding to the change amount of the target through speed ratio. Therefore, it is possible to obtain a driving force according to the depression state of the accelerator pedal.
On the other hand, the amount of change in the speed ratio of the variator when the sub-transmission mechanism is downshifted is a value that covers the speed ratio that is insufficient for the downshift of the sub-transmission mechanism, and is smaller than the amount of change in the target through speed ratio. However, since the shift of the sub-transmission mechanism proceeds in the order of the inertia phase and the torque phase, the driving force obtained by the sub-transmission mechanism is the driving force before the downshift until the inertia phase is completed (the transition to the torque phase). It remains power. Therefore, in the initial stage of the downshift of the auxiliary transmission mechanism, it is not possible to obtain a driving force corresponding to the depressed state of the accelerator pedal, and there is a problem that a stagnation occurs in a change in vehicle acceleration and the driver feels hesitation. Was.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problem, and has been made in consideration of a problem with a continuously variable transmission that can suppress shortage of driving force at the beginning of a downshift when a subtransmission mechanism downshifts based on a driving force request of a driver. It is an object to provide a control device.

In order to achieve the above object, a control device for a continuously variable transmission according to the present invention includes a variator, an auxiliary transmission mechanism, and a shift control unit.
The variator is interposed between the traveling drive source and the drive wheels, and can change the gear ratio steplessly.
The sub-transmission mechanism is provided in a drive system in which a variator is interposed, and is capable of switching a plurality of shift speeds by fastening and releasing a plurality of fastening elements.
The speed change control means controls the speed of the variator according to the target speed ratio of the auxiliary speed change mechanism such that the through speed ratio, which is the overall speed ratio achieved by the variator and the auxiliary speed change mechanism, at the time of the speed change request, matches the target value. When the sub-transmission mechanism is downshifted based on the driver's driving force request, the variator's speed ratio during the downshift and after the inertia phase is completed is determined by the cooperative speed change. The speed ratio is set to a value larger than the speed ratio of the variator set when the operation is performed. Then, when the driver operates the accelerator after the inertia phase is completed, the speed ratio of the variator is returned to the value set when performing the cooperative speed change.

In the control device for the continuously variable transmission according to the present invention, during the inertia phase of the auxiliary transmission mechanism, the driving force obtained by the auxiliary transmission mechanism is the driving force before downshifting, but the transmission ratio of the variator is set to “cooperative transmission”. By making the value larger than the value set at the time of execution, the driving force obtained by the variator can be made larger than the driving force obtained by the variator at the time of performing “cooperative shift”.
Thus, when the subtransmission mechanism performs a downshift based on a driver's driving force request, it is possible to suppress a shortage of the driving force at the beginning of the downshift. Then, the stagnation of the change in the vehicle acceleration can be reduced, and the driver can be prevented from feeling hesitation.

1 is an overall configuration diagram illustrating an engine vehicle equipped with a continuously variable transmission to which a control device according to a first embodiment is applied. FIG. 2 is a block diagram illustrating an electronic control system of the continuously variable transmission to which the control device according to the first embodiment is applied. FIG. 3 is a shift map diagram illustrating an example of a shift map stored in a storage device of the transmission controller according to the first embodiment. 3 is a flowchart illustrating a flow of a 2 → 1 downshift shift control process executed by the transmission controller according to the first embodiment. In the control device of the first comparative example, the characteristics of the accelerator opening, engine torque, target through speed ratio, target variator speed ratio, target auxiliary speed ratio, and vehicle G when the subtransmission mechanism is downshifted when a driving force is requested are determined. It is a time chart shown. In the control device of the first comparative example, the characteristics of the accelerator opening, engine torque, target through speed ratio, target variator speed ratio, target auxiliary speed ratio, and vehicle G when the downshift of the subtransmission mechanism is not performed when a driving force is requested are determined. It is a time chart shown. In the control device according to the first embodiment, the accelerator opening, the engine torque, the target through speed ratio, the actual through speed ratio, the attained target through speed ratio, the target variator speed ratio, and the target when the auxiliary transmission mechanism is downshifted when the driving force is requested. 5 is a time chart showing characteristics of a sub-gear ratio and a vehicle G. 9 is a flowchart illustrating a flow of a 2 → 1 downshift shift control process executed by the transmission controller according to the second embodiment. In the control device of the second embodiment, the accelerator opening, the engine torque, the target through speed ratio, the actual through speed ratio, the target variator speed ratio, the target auxiliary speed ratio, and the target sub speed ratio when the auxiliary transmission mechanism is downshifted when a driving force is requested. 6 is a time chart showing the respective characteristics of FIG.

  Hereinafter, an embodiment of a control device for a continuously variable transmission according to the present invention will be described based on Embodiments 1 and 2 shown in the drawings.

(Example 1)
First, the configuration of the control device of the continuously variable transmission according to the first embodiment will be described by dividing it into “overall system configuration”, “shift control configuration in shift map”, and “2 → 1 downshift shift control configuration”.

[Overall system configuration]
FIG. 1 shows an overall configuration of an engine vehicle equipped with a continuously variable transmission to which the control device of the first embodiment is applied, and FIG. 2 shows an electronic control system of a transmission controller. Hereinafter, an overall system configuration of the control device according to the first embodiment will be described with reference to FIGS. 1 and 2.
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. The “lowest speed ratio” means the maximum speed ratio of the speed change mechanism, and the “highest speed ratio” means the minimum speed ratio of the speed change mechanism.

  The vehicle equipped with the continuously variable transmission according to the first embodiment includes the engine 1 as a traveling drive source. Output rotation from the engine 1 is transmitted via a torque converter 2 with a lock-up clutch, a first gear train 3, a continuously variable transmission 4 (hereinafter simply referred to as a "transmission"), a second gear train 5, and a final reduction gear 6. And transmitted to the drive wheels 7. The second gear train 5 is provided with a parking mechanism 8 that locks the output shaft of the transmission 4 mechanically so that it cannot rotate when parking. Further, the vehicle includes an oil pump 10 driven by using a part of the power of the engine 1, a hydraulic control circuit 11 which regulates a hydraulic pressure from the oil pump 10 and supplies the hydraulic pressure to various parts of the transmission 4. A transmission controller 12 for controlling the hydraulic control circuit 11 is provided. Hereinafter, each configuration will be described.

The transmission 4 includes a continuously variable transmission mechanism 20 (hereinafter, referred to as a “variator”) and a stepped transmission mechanism 30 (hereinafter, referred to as an “auxiliary transmission mechanism”) provided in series with the variator 20. ing.
Here, “provided in series” means that the variator 20 and the subtransmission mechanism 30 are provided in series in the same power transmission path. The input shaft of the auxiliary transmission mechanism 30 may be directly connected to the output shaft of the variator 20 as in the first embodiment, or may be connected via another transmission or power transmission mechanism (for example, a gear train or a clutch). May be. Further, the input shaft of the variator 20 may be connected to the output shaft of the subtransmission mechanism 30.

  The variator 20 is a belt-type continuously variable transmission mechanism including a primary pulley 21, a secondary pulley 22, and a V-belt 23 wound between the pulleys 21 and 22. Each of the pulleys 21 and 22 includes a fixed conical plate, a movable conical plate which is disposed with the sheave surface facing the fixed conical plate and forms a V groove between the fixed conical plate, and a movable conical plate. And hydraulic cylinders 23a and 23b provided on the back surface of the movable cylinder to displace the movable conical plate in the axial direction. When the hydraulic pressure supplied to the hydraulic cylinders 23a and 23b is adjusted, the width of the V-groove changes, the contact radius between the V-belt 23 and each of the pulleys 21 and 22 changes, and the speed ratio of the variator 20 changes steplessly. .

The subtransmission mechanism 30 is a transmission mechanism having two forward speeds and one reverse speed. The subtransmission mechanism 30 is connected to a Ravigneaux-type planetary gear mechanism 31 that connects two planetary gear carriers and a plurality of rotating elements that constitute the Ravigneaux-type planetary gear mechanism 31, and a plurality of frictions that change the state of their linkage. Fastening elements (Low brake 32, High clutch 33, Rev brake 34). When the hydraulic pressure supplied to each of the frictional engagement elements 32 to 34 is adjusted, and a changeover shift is performed to change the engagement / release state of each of the frictional engagement elements 32 to 34, the shift speed of the auxiliary transmission mechanism 30 is changed.
That is, when the Low brake 32 is engaged and the High clutch 33 and the Rev brake 34 are released, the speed position of the subtransmission mechanism 30 is set to the “first speed” state. When the High clutch 33 is engaged and the Low brake 32 and the Rev brake 34 are released, the speed position of the subtransmission mechanism 30 is set to the “second speed” state where the speed ratio is smaller than the first speed. When the Rev brake 34 is engaged and the Low brake 32 and the High clutch 33 are released, the speed of the subtransmission mechanism 30 is set to the "reverse" state. Hereinafter, when the auxiliary transmission mechanism 30 is in the “first speed” state, it is referred to as “low speed mode”, and when the auxiliary transmission mechanism 30 is in the “second speed” state, it is referred to as “high speed mode”.

  As shown in FIG. 2, the transmission controller 12 (shift control means) includes a CPU 121, a storage device 122 composed of a RAM and a ROM, an input interface 123, an output interface 124, and a bus 125 for interconnecting these components. It is composed of

  The input interface 123 includes an output signal of an accelerator opening sensor 41 for detecting an accelerator opening APO, and an output signal of a primary speed sensor 42 for detecting a primary speed Npri of the variator 20 (input speed of the transmission 4). The output signal of the transmission output speed sensor 43 for detecting the output speed Nout of the auxiliary transmission mechanism 30 (the output speed of the transmission 4) is input. Further, the input interface 123 includes an output signal of an oil temperature sensor 44 for detecting an ATF oil temperature of the transmission 4, an output signal of an inhibitor switch 45 for detecting a position of a select lever, and a signal of an output torque of the engine 1. An input torque signal Te and the like are input.

  The storage device 122 stores a shift control program for the transmission 4 and a shift map (see FIG. 3) used in the shift control program. The CPU 121 reads and executes a shift control program stored in the storage device 122, performs various arithmetic processing on various signals input via the input interface 123, generates a shift control signal, and generates the generated shift control signal. The control signal is output to the hydraulic control circuit 11 via the output interface 124. Various values used in the arithmetic processing by the CPU 121 and the arithmetic results are stored in the storage device 122 as appropriate.

  The hydraulic control circuit 11 includes a plurality of flow paths and a plurality of hydraulic control valves. The hydraulic control circuit 11 controls a plurality of hydraulic control valves based on a shift control signal from the transmission controller 12 to switch the supply path of the hydraulic pressure and adjusts a required hydraulic pressure from the hydraulic pressure generated by the oil pump 10. Is supplied to each part of the transmission 4. As a result, the gear ratio of the variator 20 and the gear position of the subtransmission mechanism 30 are changed, and the transmission 4 is shifted.

[Shift control configuration using shift map]
FIG. 3 shows an example of a shift map stored in the storage device of the transmission controller. Hereinafter, a shift control configuration based on the shift map will be described with reference to FIG.

  The operating point of the transmission 4 is determined on the shift map shown in FIG. 3 based on the vehicle speed VSP and the primary rotation speed Npri. The slope of the line connecting the operating point of the transmission 4 and the zero point at the lower left corner of the transmission map is the transmission ratio of the transmission 4 (the total transmission ratio obtained by multiplying the transmission ratio of the variator 20 by the transmission ratio of the auxiliary transmission mechanism 30, that is, Speed ratio of the entire transmission 4 achieved by the variator 20 and the subtransmission mechanism 30. Hereinafter, the speed ratio will be referred to as “through speed ratio”. In this shift map, similarly to the shift map of the conventional belt-type continuously variable transmission, a shift line is set for each accelerator opening APO, and the shift of the transmission 4 is selected according to the accelerator opening APO. Is performed according to the shift line.

That is, the transmission controller 12 refers to the shift map and sets the through speed ratio corresponding to the vehicle speed VSP and the accelerator opening APO (operating state of the vehicle) as the “achieved through speed ratio”.
The “achieved through speed ratio” is a target value that the through speed ratio should ultimately reach in the operating state. Then, the transmission controller 12 sets a “target through speed ratio” which is a transient target value for causing the through speed ratio to follow the attained through speed ratio with desired response characteristics, and sets the variator 20 and the subtransmission mechanism 30. Is controlled, and the "cooperative shift" that causes the actual through speed ratio to match (follow) the target through speed ratio is performed.

When performing the “cooperative shift”, first, a target gear ratio of the auxiliary transmission mechanism 30 (hereinafter, referred to as a “target auxiliary gear ratio”) is calculated. Here, if the subtransmission mechanism 30 does not shift, the target subtransmission ratio is a speed ratio realized at the first speed or a speed ratio realized at the second speed. When the subtransmission mechanism 30 shifts, the input rotation speed and the output rotation speed of the subtransmission mechanism 30 are calculated according to the progress of the shift, and the target subtransmission ratio is calculated from the calculated value.
After calculating the target auxiliary speed ratio, the target through speed ratio is divided by the calculated target auxiliary speed ratio, and this division value is set as the target speed ratio of the variator 20 (hereinafter, referred to as “target variator speed ratio”). The speed control of the variator 20 is performed so that the speed ratio of the variator 20 matches (follows) the target variator speed ratio. As a result, the target variator speed ratio is controlled in accordance with the target auxiliary speed ratio so that the through speed ratio follows the target value.

For simplicity, FIG. 3 shows a full load line (shift line when accelerator opening APO = 8/8), a partial line (shift line when accelerator opening APO = 4/8), and a coast line (shift line when accelerator opening APO = 4/8). Only the shift line when the accelerator opening APO = 0 is shown.
Further, the vehicle speed VSP is obtained from the output rotation speed Nout of the subtransmission mechanism 30 and the gear ratio of the second gear train 5 and the final reduction gear 6.

When the transmission 4 is in the low-speed mode, the transmission 4 has a low-speed mode lowest line obtained by maximizing the speed ratio of the variator 20 and a low-speed mode highest line obtained by minimizing the speed ratio of the variator 20. And can be shifted between. At this time, the operating point of the transmission 4 moves in the area A and the area B. On the other hand, when the transmission 4 is in the high-speed mode, the transmission 4 includes a high-speed mode lowest line obtained by maximizing the speed ratio of the variator 20 and a high-speed mode highest line obtained by minimizing the speed ratio of the variator 20. , Can be shifted between. At this time, the operating point of the transmission 4 moves in the B area and the C area.
Note that the “A region” is a region surrounded by the low-speed mode lowest line and the high-speed mode lowest line. The “B region” is a region surrounded by the high-speed mode lowest line and the low-speed mode highest line. The “C region” is a region surrounded by the low-speed mode highest line and the high-speed mode highest line.

  The speed ratio of each speed stage of the subtransmission mechanism 30 is such that the speed ratio corresponding to the low-speed mode highest line (low-speed mode highest High speed ratio) corresponds to the high-speed mode lowest line (high-speed mode lowest speed). Ratio). As a result, the low speed mode ratio range which is a range of the through speed ratio of the transmission 4 that can be obtained in the low speed mode and the high speed mode ratio range which is a range of the through speed ratio of the transmission 4 that can be obtained in the high speed mode are partially. Overlaps. When the operating point of the transmission 4 is in the B region (overlap region) between the high-speed mode lowest line and the low-speed mode high line, the transmission 4 can select either the low-speed mode or the high-speed mode. ing.

  Further, on the speed change map, a mode switching up speed change line (1 → 2 up speed change line of the auxiliary speed change mechanism 30) for performing an up speed change of the auxiliary speed change mechanism 30 has a low side speed ratio (speed change) from the low speed mode Highest line. (Larger ratio). Further, on the shift map, a mode switching down shift line (downshift line from 2 to 1 of the auxiliary transmission mechanism 30) for performing a down shift of the auxiliary transmission mechanism 30 is a high side speed ratio (speed ratio) from the high-speed mode lowest line. Small).

  Then, when the operating point of the transmission 4 crosses the mode switching up shift line or the mode switching down shift line, that is, when the target through speed ratio of the transmission 4 changes across the mode switching speed ratio, When the transmission gear ratio coincides with the switching gear ratio, the transmission controller 12 performs mode switching gear control. When performing “cooperative shift” during this mode switching shift control, the transmission controller 12 adjusts the actual through speed ratio according to the target speed ratio of the auxiliary speed change mechanism 30 so that the actual through speed ratio follows the target through speed ratio (target value). Thus, the speed ratio of the variator 20 is controlled. Specifically, the speed ratio of the variator 20 is set to a value obtained by dividing the target through speed ratio by the speed ratio of the subtransmission mechanism 30.

[Shift control configuration during 2 → 1 downshift]
FIG. 4 is a flowchart illustrating the flow of a 2 → 1 downshift shift control process executed by the transmission controller of the first embodiment. Hereinafter, each step of FIG. 4 representing the shift control configuration at the time of the 2 → 1 downshift of the first embodiment will be described.

  In step S1, it is determined whether or not the transmission 4 is in the high speed mode, that is, whether or not the subtransmission mechanism 30 is in the second speed. If YES (high-speed mode), the process proceeds to step S2 assuming that downshifting is possible. In the case of NO (low speed mode), it is determined that downshifting is not possible, and this control cannot be applied.

In step S2, following the determination of the high-speed mode in step S1, it is determined whether or not a downshift request of the auxiliary transmission mechanism 30 as a mode switching request has occurred. If YES (there is a request), it is determined that a mode switching request (a downshift request for the subtransmission mechanism 30) has occurred, and the process proceeds to step S3. If NO (no request), it is determined that a mode switching request (a downshift request for the subtransmission mechanism 30) has not occurred, and the process proceeds to step S10.
Here, the presence / absence of the mode switching request is performed based on the vehicle speed, the accelerator opening, and the accelerator opening speed (the accelerator pedal depression speed). When the accelerator opening exceeds a threshold determined according to the vehicle speed and the accelerator opening exceeds a preset threshold, a mode switching request (downshift request of the subtransmission mechanism 30) is generated.

In step S3, following the determination that there is a mode switching request in step S2, the downshift of the auxiliary transmission mechanism 30 is started, and the process proceeds to step S4.
Here, in order to downshift the subtransmission mechanism 30, first, the output torque of the engine 1, which is the transmission input torque, is increased. Next, the engagement capacity of the high clutch 33 in the engaged state is reduced, and the high clutch 33 is brought into the slip engaged state. As a result, the input rotation speed (= variator output rotation speed) of the subtransmission mechanism 30 gradually increases, and the speed ratio of the subtransmission mechanism 30 increases (changes to the low side). Then, when the input rotation speed of the subtransmission mechanism 30 increases to the target rotation speed, the high clutch 33 is released while increasing the engagement capacity of the low brake 32 while maintaining the rotation speed. As a result, the driving force obtained by the subtransmission mechanism 30 increases. When the shifting of the low brake 32 and the high clutch 33 is completed, the downshift of the subtransmission mechanism 30 is completed.
The period during which the input rotation speed (= variator output rotation speed) of the subtransmission mechanism 30 increases due to the high clutch 33 being in the slip engagement state, that is, the period during which the speed ratio of the subtransmission mechanism 30 is increased, is inertia. It is called a phase. A period during which the driving force obtained by the subtransmission mechanism 30 increases by increasing the engagement capacity of the low brake 32 is referred to as a torque phase.

In step S4, following the start of the downshift of the subtransmission mechanism 30 in step S3, it is determined whether or not the "D ratio" is equal to or greater than a preset first threshold value. If YES (D ratio ≧ first threshold), the process proceeds to step S5. If NO (D ratio <first threshold value), the process proceeds to step S11.
Here, the "D ratio" is a speed ratio difference between the attained through speed ratio before the mode switching request is generated and the attained through speed ratio after the mode switching request is generated. The “first threshold value” is a value arbitrarily set based on whether or not hesitation is given to the driver when the speed ratio of the variator 20 is set to the value at the time of the “cooperative shift”. For example, it is set to a value equivalent to the speed ratio difference (difference between the first speed sub speed ratio and the second speed sub speed ratio) in the subtransmission mechanism 30.

In step S5, following the determination that D ratio ≧ the first threshold value in step S4, the value obtained by dividing the target variator speed ratio by the target through speed ratio by the second speed target auxiliary speed ratio on the assumption that the driver's acceleration request is large. And the variator 20 is controlled in accordance with the set target variator speed ratio, and the process proceeds to step S6.
Here, the “second-speed target auxiliary speed ratio” is a target speed ratio when the auxiliary speed change mechanism 30 is in the second speed state (before downshift). On the other hand, the target auxiliary speed ratio during the inertia phase in the downshift of the auxiliary speed change mechanism 30 is constantly increased from the 2nd speed target auxiliary speed ratio (low) due to an increase in the input rotation speed of the auxiliary speed change mechanism 30. Change to the side). Therefore, the target auxiliary speed ratio at the second speed is smaller than the target auxiliary speed ratio during the inertia phase in the downshift.
Therefore, a value obtained by dividing the target through speed ratio by the target auxiliary speed ratio at the second speed is larger than a value obtained by dividing the target through speed ratio by the target auxiliary speed ratio during the inertia phase in the downshift. Become. As a result, the target variator speed ratio is set to a value larger than the target variator speed ratio set when performing “cooperative shift” (hereinafter, “value at the time of performing“ cooperative shift ”)”.

In step S6, following the setting of the target variator speed ratio in step S5, a regulation process of the set target variator speed ratio is performed, and the process proceeds to step S7.
Here, the regulation process of the variator speed ratio means that the required vehicle G calculated from the accelerator opening APO occurs, or that the target variator speed ratio set in step S5 has reached the predetermined upper limit value α. In this case, the target variator speed ratio is maintained at the value at that time. That is, the target variator speed ratio is provided with the upper limit regulation value α, and for example, it is regulated that the target variator speed ratio keeps increasing until the required vehicle G occurs.
The “upper limit value α” is a limit value that restricts a change in the speed ratio of the variator 20 to the low side. For example, it is set arbitrarily based on the overrev rotation speed of the engine 1 and the like.

In step S7, following the execution of the target variator speed ratio restriction process in step S6, the inertia phase in the downshift of the subtransmission mechanism 30 is completed, and it is determined whether or not the driver has performed an accelerator operation. If YES (the inertia phase is completed and the accelerator operation is performed), the process proceeds to step S8. If NO (the inertia phase is not completed or there is no accelerator operation), the process returns to step S5 assuming that the target variator speed ratio is kept set to a value larger than that in the case of performing the cooperative speed change.
Here, the presence or absence of the accelerator operation is determined based on whether or not a “target speed ratio deviation”, which is a difference between the reached through target speed ratio and the target through speed ratio, is larger than a second threshold value set in advance. When the driver performs the accelerator operation, the attained through speed ratio changes, and a difference occurs between the attained through speed ratio and the target through speed ratio. That is, it is determined that the accelerator operation by the driver has occurred when target speed ratio deviation ≧ second threshold value. The “second threshold value” is a value arbitrarily set based on whether or not the accelerator operation has been performed.

In step S8, following the determination that the inertia phase has been completed and the accelerator operation has been performed in step S7, a target variator speed ratio corresponding to the speed profile of the variator 20 until the target through speed ratio matches the attained through speed ratio is generated. The variator 20 is controlled in accordance with the generated target variator speed ratio, and the process proceeds to step S9.
At this time, it is assumed that the variator 20 shifts (upshifts) at the maximum shift speed within a range where belt slip does not occur. Further, thereby, the variator speed ratio changes toward the value at the time of performing the “cooperative speed change” (the value obtained by dividing the target through speed ratio by the current target auxiliary speed ratio).

In step S9, following the generation of the target variator speed ratio in step S8, it is determined whether or not the target variator speed ratio deviation is less than a third threshold value set in advance. If YES (target variator gear ratio deviation <third threshold value), the variator gear ratio matches the value at the time of executing the “cooperative gear shift” (the value obtained by dividing the target through gear ratio by the current target auxiliary gear ratio). And proceed to the end. If NO (target variator speed ratio deviation ≧ third threshold value), the variator speed ratio is larger than the value at the time of performing “cooperative speed change” (the value obtained by dividing the target through speed ratio by the current target auxiliary speed ratio). And returns to step S8.
Here, the "target variator speed ratio deviation" is obtained by dividing the target variator speed ratio generated in step S8 by the target variator speed ratio at the time of executing the "cooperative shift" (the target through speed ratio is divided by the current target auxiliary speed ratio). Value). The “third threshold value” is a value by which the variator speed ratio can be determined to be equal to the value at the time of the “cooperative speed change” (the value obtained by dividing the target through speed ratio by the current target auxiliary speed ratio). Is set to

  In step S10, following the determination in step S2 that there is no mode switching request, the subtransmission mechanism 30 is maintained in the second speed state, the high speed mode is continued, and the process proceeds to the end.

In step S11, following the determination of D ratio <first threshold value in step S4, it is determined that the driving force demand of the driver can be satisfied even when the normal "cooperative shift" is performed, and the target variator speed ratio is set to the auxiliary speed change mechanism. 30 is set to a value obtained by dividing the target through speed ratio by the target sub speed ratio that is constantly increasing from the speed ratio realized in the second speed to the speed ratio realized in the first speed, and the set target variator speed ratio The variator 20 is controlled accordingly and the process proceeds to the end.
That is, when the process proceeds to step S11, "cooperative shift" for controlling the target variator speed ratio in accordance with the target auxiliary speed ratio is performed so that the through speed ratio follows the target value.

Next, the operation will be described.
First, "control and operation of the first comparative example" and "control and operation of the second comparative example" will be described. Next, the "shift control operation" in the control device for the continuously variable transmission according to the first embodiment will be described.

[Control of first comparative example and its operation]
FIG. 5 shows an accelerator opening, an engine torque, a target through gear ratio, a target variator gear ratio, a target auxiliary gear ratio, and a vehicle G when the auxiliary transmission mechanism is downshifted when a driving force is required in the control device of the first comparative example. 6 is a time chart showing the respective characteristics of FIG. Hereinafter, the control and the operation of the first comparative example will be described with reference to FIG.

  The first comparative example includes a variator capable of continuously changing the speed ratio, and a stepped subtransmission mechanism provided in series with the variator. When changing the through speed ratio to the low side based on the driver's driving force request, the auxiliary speed change mechanism controls only the variator speed ratio to the low side without shifting, and follows the through speed ratio to the target value. Let it. In this case as well, since the speed ratio of the variator is controlled according to the target auxiliary speed ratio (constant value), "cooperative speed change" is performed.

That is, when the low-speed mode (subtransmission mechanism 1 speed), the accelerator opening is changed at time t ₁ point shown in FIG. 5, the engine torque starts to increase based on the change in the accelerator opening, target through The gear ratio changes to the low side. At this time, since the first speed is selected in the sub-transmission mechanism, downshifting cannot be performed, and the target speed ratio of the sub-transmission mechanism (hereinafter, referred to as “target sub-speed ratio”) is the speed realized in the first speed. Maintain the ratio.

  On the other hand, the target speed ratio of the variator (hereinafter referred to as “target variator speed ratio”) is set to a value obtained by dividing the target through speed ratio by the target auxiliary speed ratio. In the first comparative example, only the speed of the variator is changed. As a result, the through speed ratio follows the target value. Therefore, the change amount of the speed ratio of the variator is substantially equal to the change amount of the target through speed ratio.

  Here, the driving force transmitted to the variator changes according to the change in the gear ratio, so that the acceleration (vehicle G) acting on the vehicle changes (increases) in accordance with the shift of the variator. As a result, it is possible to obtain a driving force according to the depression state of the accelerator pedal.

[Control of second comparative example and its operation]
FIG. 6 shows an accelerator opening, an engine torque, a target through speed ratio, a target variator speed ratio, a target auxiliary speed ratio, and a target auxiliary speed ratio when the auxiliary transmission mechanism is downshifted when a driving force is requested in the control device of the second comparative example. 6 is a time chart showing the respective characteristics of FIG. Hereinafter, the control and the operation of the second comparative example will be described with reference to FIG.

  The second comparative example includes a variator capable of continuously changing the speed ratio, and a stepped sub-transmission mechanism provided in series with the variator. Then, when changing the through speed ratio to the low side based on the driver's driving force request, the sub speed change mechanism is downshifted, and the speed ratio of the variator is controlled in accordance with the target auxiliary speed ratio to set the target speed. Perform "cooperative shift" to follow the value.

That is, when the high-speed mode (subtransmission mechanism 2 speed), the accelerator opening is changed at time t ₂ point shown in FIG. 6, the engine torque starts to increase based on the change in the accelerator opening, target through The gear ratio changes to the low side. Further, a downshift request of the subtransmission mechanism is generated based on the accelerator opening and the accelerator opening speed at this time. As a result, the downshift is started in the sub-transmission mechanism, and the engagement capacity of the High clutch gradually decreases, so that the input rotation speed (= variator output rotation speed) of the sub-transmission mechanism increases, and the target sub-transmission ratio is reduced. The rising inertia phase proceeds.

  On the other hand, the target variator speed ratio is set to a value obtained by dividing the target through speed ratio by the target auxiliary speed ratio. In the second comparative example, the through speed ratio is reduced by downshifting the auxiliary speed change mechanism and shifting the variator. It will follow the target value. Therefore, the amount of change in the speed ratio of the variator is smaller than the amount of change in the target through speed ratio.

  Here, during the period in which the target sub-transmission ratio is increased (inertia phase), the driving force obtained by the sub-transmission mechanism is equivalent to before the downshift (second speed driving force). Therefore, although the vehicle G increases due to the downshift of the variator, the driving force obtained by the subtransmission mechanism does not increase, so that the change of the vehicle G does not correspond to the increase in the engine torque. A stagnation occurs in the upward change.

Target sub gear ratio at time t ₃ time reaches the gear ratio to achieve at the first speed, that the High clutch is disengaged torque capacity of Low brake while rising, torque driving force obtained by the subtransmission mechanism is increased Move to the phase. If transition to the torque phase, the driving force obtained by the subtransmission mechanism gradually increases, at the timing when the downshift of the subtransmission mechanism is completed at time t ₄ time points, after a downshift (first speed drive Force), a considerable driving force can be obtained.

  As described above, when the “cooperative shift” is performed when the sub-transmission mechanism shifts down based on the driving force request of the driver, the driving force corresponding to the depressed state of the accelerator pedal is generated at the beginning of the down-shift of the sub-transmission mechanism. I can't get it. As a result, as shown by the dashed line A in FIG. 6, the change in the upward movement of the vehicle G stagnates, causing a problem that the driver feels hesitation.

[Shift control action]
FIG. 7 shows the control device according to the first embodiment in which the accelerator opening, engine torque, target through speed ratio, actual through speed ratio, attained target through speed ratio, and target variator when the subtransmission mechanism is downshifted when a driving force is requested. 5 is a time chart showing characteristics of a gear ratio, a target auxiliary gear ratio, and a vehicle G. Hereinafter, the shift control operation in the first embodiment will be described with reference to FIG.

Traveling at a high speed mode in the transmission 4 in Example 1 (subtransmission mechanism 30 is the second speed), when the accelerator pedal at time t ₁₁ point shown in FIG. 7 is depressing, based on the change in the accelerator opening The engine torque rises. Then, in the flowchart shown in FIG. 4, the process proceeds from step S1 to step S2, and it is determined whether a mode switching request, that is, a downshift request of the subtransmission mechanism 30 has been generated.

  If a mode switching request is output based on the accelerator opening, the accelerator opening speed, the vehicle speed, etc., the downshift of the subtransmission mechanism 30 is started. Further, the process proceeds to step S2 → step S3 → step S4, and it is determined whether or not the D ratio is equal to or more than the first threshold. In the case shown in FIG. 7, it is determined that the D ratio is greater than the first threshold value, and the process proceeds to step S5 to set the target variator speed ratio to a value obtained by dividing the target through speed ratio by the target auxiliary speed ratio at the second speed. Is done. The variator 20 performs shift control (shift control to the low side) according to the set target variator speed ratio.

Here, the “second-speed target auxiliary speed ratio” is the target auxiliary speed ratio when the auxiliary speed change mechanism 30 is in the second speed (before downshift). On the other hand, in the subtransmission mechanism 30 in which the downshift has started, the target subtransmission ratio gradually increases from the transmission ratio at the second speed during the inertia phase. Therefore, the target auxiliary speed ratio at the second speed is smaller than the target auxiliary speed ratio during the inertia phase in the downshift of the auxiliary speed change mechanism 30.
Therefore, during the inertia phase in the downshift of the subtransmission mechanism 30, the target variator speed ratio is set to a value larger by Δx than the value at the time of performing “cooperative shift” (shown by a broken line in FIG. 7). That is, in the first embodiment, during the inertia phase in the downshift of the subtransmission mechanism 30, the speed ratio of the variator 20 is a value lower than the value at the time of the “cooperative shift”.

  Then, when the speed ratio of the variator 20 is shifted to a lower side than the value at the time of performing the “cooperative shift”, the change (increase) of the vehicle G also performs the “cooperative shift” (FIG. 7). At the bottom of the drawing). As a result, it is possible to alleviate the stagnation of the upward change of the vehicle G and suppress the hesitation felt by the driver.

  Further, as in the first embodiment, the target variator speed ratio during the inertia phase in the downshift of the auxiliary speed change mechanism 30 is set to the target through speed ratio at the 2nd speed target auxiliary speed ratio (the target auxiliary speed ratio before the downshift). Can be set to a value that is reliably larger than the value at the time of executing the “cooperative shift”, and can be easily calculated.

In the first embodiment, the process proceeds from step S5 to step S6, and the variator speed ratio regulating process is performed. That is, at time t ₁₂ the time, when the target variator speed ratio reaches the upper regulation value alpha, the target variator is maintained at this upper limit regulation value alpha. Thereby, it is possible to suppress the engine speed from becoming unnecessarily high.

Thereafter, the target auxiliary transmission ratio at time t ₁₃ the time is reaches the gear ratio to achieve at the first speed, torque phase of the engagement capacity of the Low brake is released High clutch while increase is initiated. As a result, the driving force obtained by the auxiliary transmission mechanism 30 increases, and the vehicle G also increases as the driving force increases. Then, when a downshift of the subtransmission mechanism 30 is completed at time t ₁₄ when the vehicle G is also constant increase in the driving force obtained by the subtransmission mechanism 30 is stopped.

  In the first embodiment, even after the inertia phase in the downshift of the subtransmission mechanism 30 is completed, the target variator speed ratio is set to a value larger than the value at the time of performing the “cooperative shift”. That is, the target variator speed ratio is kept set to the upper limit regulation value regardless of the speed change state of the subtransmission mechanism 30.

  Thereby, in the inertia phase in the downshift of the subtransmission mechanism 30, it is possible to secure a longer time in which the speed ratio of the variator 20 is set to a value on the low side than the value when the “cooperative shift” is performed. For this reason, it is possible to more reliably suppress the shortage of the driving force generated in the initial stage of the downshift of the subtransmission mechanism 30.

The weakened stepping force of the accelerator pedal at time t ₁₅ when the accelerator opening APO is small, the step S7 → proceeds to step S8 → step S9, the target variator speed ratio "coordinated shift" exemplary time value (now (A value obtained by dividing the target through speed ratio by the target auxiliary speed ratio). Then, the speed change control (upshift) of the variator 20 is performed so that the target variator speed ratio follows the generated speed profile, and the target variator speed ratio is returned to the value at the time of performing the “cooperative shift”.

  Here, by returning the target variator speed ratio to the value at the time of performing the “cooperative shift”, the driving force obtained by the variator 20 changes (decreases), and the vehicle G fluctuates. However, by setting the timing at which the target variator speed ratio is adjusted to the “cooperative shift” to the timing at which the driver operates the accelerator after the inertia phase in the downshift of the subtransmission mechanism 30 is completed, the target through-speed associated with the accelerator operation is obtained. The target variator speed ratio can be returned to the value at the time of performing the “cooperative speed change” in accordance with the timing at which the speed ratio changes. Therefore, even if the vehicle G fluctuates by returning the target variator speed ratio to the value at the time of performing the “cooperative shift”, it can be mixed with the vehicle G fluctuation accompanying the change in the target through speed ratio caused by the accelerator operation. , It is possible to reduce discomfort to the driver.

  In the first embodiment, when the D ratio is smaller than the preset first threshold value, the process proceeds from step S4 to step S11, and the target variator speed ratio is realized at the first speed from the speed ratio realized at the second speed. The target through speed ratio is set to a value obtained by dividing the target through speed ratio by the target sub speed ratio that is constantly increasing to the speed ratio. That is, a normal “cooperative shift” that controls the target variator speed ratio in accordance with the target auxiliary speed ratio is performed so that the through speed ratio follows the target value. As a result, in a scene in which the target variator speed ratio during the inertia phase in the downshift of the subtransmission mechanism 30 is set to a value lower than that during the execution of the “cooperative shift”, the driver greatly increases the accelerator pedal in a short time. (Such as sudden depression of the accelerator pedal). Therefore, it is possible to prevent the target variator speed ratio from being set to an unnecessarily large value, and to suppress the occurrence of uncomfortable feeling for the driver.

Next, effects will be described.
In the control device for the continuously variable transmission according to the first embodiment, the following effects can be obtained.

(1) a variator 20 interposed between the traveling drive source (engine 1) and the drive wheels 7 and capable of changing the gear ratio steplessly;
A stepped sub-transmission mechanism 30 that is provided in a drive system in which the variator 20 is interposed and that can switch a plurality of shift speeds by fastening and releasing a plurality of fastening elements (a low brake 32 and a high clutch 33);
When a shift is requested, the variator 20 is driven in accordance with the speed ratio of the sub-transmission mechanism 30 so that the through speed ratio, which is the overall speed ratio achieved by the variator 20 and the sub-transmission mechanism 30, follows a target value. A shift control means (transmission controller 12) for performing a cooperative shift for controlling a speed ratio;
In the control device of the continuously variable transmission having
When the downshift of the subtransmission mechanism 30 is performed based on a driver's driving force request, the shift control means (transmission controller 12) changes the speed ratio of the variator 20 during the inertia phase in the downshift by the cooperative shift. Is set to a value larger than the speed ratio of the variator 20 set when performing the above.
Thereby, when the subtransmission mechanism 30 downshifts based on the driver's driving force request, it is possible to suppress the shortage of the driving force at the beginning of the downshift.

(2) The shift control means (transmission controller 12) changes the speed ratio of the variator 20 during the inertia phase in the downshift to the speed ratio of the subtransmission mechanism 30 before the downshift (the target speed at the second speed). (Speed change ratio) divided by the through speed change ratio.
As a result, in addition to the effect of (1), the target variator speed ratio can be set to a value that is reliably larger than the value at the time of performing “cooperative speed change”, and can be easily calculated.

(3) The shift control means (transmission controller 12) is configured to set an upper limit value α for the speed ratio of the variator 20 during the inertia phase in the downshift.
Thereby, in addition to the effect of (1) or (2), it is possible to suppress the engine speed from becoming unnecessarily high.

(4) The shift control means (transmission controller 12) sets the speed ratio of the variator 20 after the inertia phase in the downshift is completed to the speed ratio of the variator 20 set when the cooperative shift is performed. It is configured to be set to a value larger than.
Accordingly, in addition to the effect of any one of (1) to (3), in the inertia phase in the downshift of the subtransmission mechanism 30, the speed ratio of the variator 20 is set to a value lower than the value at the time of performing the “cooperative shift”. Can be secured for a long time, and the driving force shortage can be more reliably suppressed.

(5) The shift control means (transmission controller 12) sets the speed ratio of the variator 20 when performing the cooperative shift, when the driver operates the accelerator after the inertia phase in the downshift is completed. To return to the value to be set.
As a result, in addition to the effect of (4), a change in the vehicle G caused by returning the target variator speed ratio to the value at the time of performing the "cooperative shift" is caused by a change in the target through speed ratio with the accelerator operation. This can be mixed with the fluctuation of the vehicle G, and the discomfort to the driver can be reduced.

(Example 2)
The second embodiment is an example in which the speed ratio of the variator is returned to a value set when performing “cooperative shift” when the inertia phase in the downshift of the auxiliary transmission mechanism is completed.

FIG. 8 is a flowchart illustrating the flow of a 2 → 1 downshift shift control process executed by the transmission controller according to the second embodiment. Hereinafter, with reference to FIG. 8, each step of FIG. 8 illustrating the shift control configuration at the time of the 2 → 1 downshift of the first embodiment in the control device of the second embodiment will be described.
Steps S1 to S5 and steps S10 and S11 are the same as those in the first embodiment, and a detailed description thereof will be omitted.

In step S7A of the shift control process at the time of the 2 → 1 downshift in the second embodiment, as shown in FIG. 8, at step S6, the process of regulating the target variator speed ratio during the inertia phase in the downshift of the subtransmission mechanism 30 is performed. Is performed, it is determined whether or not the inertia time in the downshift of the subtransmission mechanism 30 started in step S3 has reached or exceeded a preset threshold time. If YES (inertia time ≧ threshold time), the process proceeds to step S8A. If NO (inertia time <threshold time), the process returns to step S5, assuming that the target variator speed ratio may be set to a value larger than the value at the time of performing “cooperative shift”.
Here, the “threshold time” is a timing at which the upshift of the variator 20 is started in order to make the target variator speed ratio equal to the value at the time of performing the “cooperative shift” at the time of completion of the inertia phase. The variator 20 is up-shifted at the upper limit speed, and the target variator speed ratio is calculated backward at the completion of the inertia phase so that the target variator speed ratio matches the value at the time of the execution of the "cooperative shift".

  In step S8A, following the determination that the inertia time ≧ the threshold time in step S7A, the target variator speed ratio according to the speed profile of the variator 20 until the target variator speed ratio matches the value at the time of performing the “cooperative shift” is set. The generated variator 20 is controlled in accordance with the generated target variator speed ratio, and the process proceeds to step S9A.

  In step S9A, following the generation of the target variator speed ratio in step S8A, the target variator speed ratio becomes equal to or less than the value at the time of performing the “cooperative shift” (the value obtained by dividing the target through speed ratio by the current target auxiliary speed ratio). Determine whether or not it has been reached. If YES (target variator speed ratio ≦ target through speed ratio / target auxiliary speed ratio), the process proceeds to the end, assuming that the target variator speed ratio matches the value at the time of executing “cooperative speed change”. In the case of NO (target variator speed ratio> target through speed ratio / target auxiliary speed ratio), the target variator speed ratio does not match the value at the time of performing the “cooperative speed change”, and the upshift of the variator 20 is continued. Then, the process returns to step S8A.

  FIG. 9 shows an accelerator opening, an engine torque, a target through speed ratio, an actual through speed ratio, a target variator speed ratio, and a target auxiliary speed when the subtransmission mechanism is downshifted when a driving force is requested in the control device of the second embodiment. It is a time chart which shows each characteristic of ratio and vehicle G. Hereinafter, the shift control operation in the second embodiment will be described with reference to FIG.

Traveling at a high speed mode in the transmission 4 in Example 1 (subtransmission mechanism 30 is the second speed), when the accelerator pedal at time t ₂₁ point shown in FIG. 9 is depressing, based on the change in the accelerator opening The engine torque rises. Then, when a mode switching request, that is, a downshift request for the subtransmission mechanism 30 is generated and the D ratio is equal to or greater than the first threshold, in the flowchart shown in FIG. 8, step S1, step S2, step S3, step S4, and step S4 are performed. Proceed to step S5. As a result, the downshift of the subtransmission mechanism 30 is started, while the target variator speed ratio is set to a value obtained by dividing the target through speed ratio by the second speed target auxiliary speed ratio, and the set target variator speed ratio is set. The speed of the variator 20 is controlled according to.

  For this reason, during the inertia phase in the downshift of the subtransmission mechanism 30, the speed ratio of the variator 20 is a lower value than the value at the time of performing the “cooperative shift”.

Thereafter, the process proceeds to step S5 → step S6, regulation processing of the variator gear ratio is performed and the target variator speed ratio at time t ₂₂ the time reaches the upper regulation value alpha, the target variator, maintained at this upper limit regulation value alpha Is done.

Then, at time t ₂₃ time, if the inertia time in a downshift of the subtransmission mechanism 30 is started at time t ₂₁ the time has reached the threshold time set in advance, the process proceeds to step S7A → Step S8A. As a result, the shift profile of the variator 20 is generated until the target variator speed ratio matches the value at the time of performing the “cooperative shift” (the value obtained by dividing the target through speed ratio by the current target auxiliary speed ratio). Then, the shift control (upshift) of the variator 20 is performed so that the target variator speed ratio follows the generated shift profile, and the target variator speed ratio is returned to the value at the time of performing the “cooperative shift”.
When the target variator speed ratio is returned to the value at the time of the “cooperative shift”, the driving force obtained by the variator 20 changes, and the vehicle G fluctuates (thrust-up shock).

Then, at time t ₂₄ the time, when the inertia phase at the downshift in the subtransmission mechanism 30 is completed, the target variator speed ratio corresponds to the value at "coordinated shift" implementation. Further, in this time t ₂₄ time, so that the actual through speed ratio also agrees with the target through speed ratio.
As a result, it is possible to prevent the variator 20 from being upshifted after the torque phase in the downshift of the subtransmission mechanism 30, and to suppress the driver from feeling uncomfortable.

That is, if the downshift of the subtransmission mechanism 30 shifts to the torque phase, the driving force after the downshift can be obtained by the subtransmission mechanism 30, so that the driving force according to the driver's driving force request can be covered. It is possible to eliminate the driving force shortage. Therefore, when the inertia phase is completed (when the torque phase starts), the target variator speed ratio is made equal to the value at the time of performing the “cooperative shift”, thereby preventing unnecessary driving force from being generated.
On the other hand, in order to make the target variator speed ratio equal to the value at the time of performing “cooperative shift”, it is necessary to upshift the variator 20. If the upshift of the variator 20 is not completed at the time of completion of the inertia phase in the downshift of the subtransmission mechanism 30, the variator 20 is upshifted during the torque phase. Therefore, although the driver requests the driving force, the variator 20 performs an upshift, and the driving force obtained by the variator 20 decreases. This gives the driver a sense of discomfort.
Therefore, by completing the upshift of the variator 20 when the inertia phase in the downshift of the subtransmission mechanism 30 is completed, it is possible to prevent the driver from feeling uncomfortable.

  In particular, as in the second embodiment, when the inertia phase in the downshift of the subtransmission mechanism 30 is completed, that is, simultaneously with the completion of the inertia phase, the target variator speed ratio is made to match the value at the time of the “cooperative shift”. In such a case, the upshift of the variator 20 after the torque phase is prevented while maximizing the time for setting the transmission ratio of the variator 20 to a value (lower side value) larger than the value at the time of performing the “cooperative shift”. can do.

  In the second embodiment, the “upper limit value α” set during the process of regulating the variator speed ratio during the inertia phase in the downshift of the subtransmission mechanism 30 is changed to the target variator speed ratio at the completion of the inertia phase. It may be set to a value that can be returned to the value at the time of “cooperative shift”. Here, as the target variator speed ratio is set to a value larger than the value at the time of performing the “cooperative shift”, that is, as the value is set to a low value, the target variator speed ratio is separated from the value at the time of performing the “cooperative shift”. On the other hand, by setting the “upper limit value α” to a value that can return the target variator speed ratio at the time of the completion of the inertia phase to the value at the time of executing the “cooperative shift”, the target value at the time of the completion of the inertia phase is set. It is possible to prevent the variator speed ratio from exceeding the value at the time of performing the “cooperative speed change”.

Next, effects will be described.
In the control device for the continuously variable transmission according to the second embodiment, the following effects can be obtained.

(6) The shift control means (transmission controller 12) returns the speed ratio of the variator 20 to a value set when the cooperative shift is performed at the time of completion of the inertia phase in the downshift.
Thereby, the upshift of the variator 20 after the torque phase is prevented while maximizing the time for setting the speed ratio of the variator 20 to a value (low-side value) larger than the value at the time of performing the “cooperative shift”. Thus, it is possible to prevent the driver from feeling uncomfortable.

  As described above, the control device for the continuously variable transmission according to the present invention has been described based on the first and second embodiments. However, the specific configuration is not limited to these embodiments, and the claims are not limited thereto. Changes and additions to the design are permitted without departing from the gist of the claimed invention.

  In the first and second embodiments, the “D ratio” (the difference between the attained through speed ratio before the occurrence of the mode switching request and the attained through speed ratio after the occurrence of the mode switching request) is equal to or greater than the preset first threshold value. Only in the case of, the example in which the target variator speed ratio during the inertia phase in the downshift of the subtransmission mechanism 30 is set to a value larger than the value at the time of performing “cooperative shift” has been described. However, it is not limited to this. When the “accelerated shift” is performed and the acceleration obtained after a predetermined time from the generation of the driving force request of the driver cannot satisfy the target acceleration, this control (the “variable cooperative shift” is performed for the target variator speed ratio during the inertia phase in the downshift) (Set to a value greater than the hour value).

Further, in the second embodiment, the example in which the target variator speed ratio is returned to the value at the time of performing the “cooperative shift” when the inertia phase in the downshift of the subtransmission mechanism 30 is completed has been described, but the invention is not limited thereto. For example, the target variator speed ratio may be made equal to the value at the time of performing the “cooperative shift” until the inertia phase is completed, that is, during the inertia phase.
Even in this case, it is possible to prevent the variator 20 from performing an upshift after the torque phase in the downshift of the subtransmission mechanism 30, and to suppress the driver from feeling uncomfortable.

  Further, in the first embodiment, even after the inertia phase in the downshift of the subtransmission mechanism 30 is completed, when the target variator speed ratio is set to a value larger than the value at the time of performing the “cooperative shift”, the target variator speed ratio Is set to the upper limit value, but the present invention is not limited to this. That is, if the target variator speed ratio after the completion of the inertia phase is set to a value larger than the value at the time of performing the “cooperative shift”, the speed ratio of the variator 20 is set to be larger than the value at the time of performing the “cooperative shift” in the inertia phase. Also, a long time set to the low value can be secured, and shortage of the driving force can be more reliably suppressed. Therefore, after the inertia phase is completed, the target variator speed ratio may be reduced below the upper limit regulation value, and may be set to, for example, a value 300 rpm larger (set to the low side) than the value at the time of performing the “cooperative shift”.

Also, only when the driver's required driving force is extremely large, the target variator speed ratio is set to a value larger than the value at the time of executing the "cooperative shift" even after the inertia phase is completed, and the driver's required driving force is moderate. For example, before or at the completion of the inertia phase, the target variator speed ratio may be returned to the value at the time of performing the “cooperative shift”.
In this manner, the timing at which the target variator gear ratio is returned to the value at the time of the “cooperative shift” is determined according to the magnitude of the driver's required driving force, so that the driver's required driving force and the drive actually transmitted to the vehicle are determined. The deviation from the force can be suppressed, and even if the vehicle G is different from the required vehicle G required from the accelerator opening or the like, the discomfort to the driver can be reduced.

In the first and second embodiments, the variator speed ratio regulating process is performed to maintain the target variator speed ratio during the inertia phase in the downshift of the subtransmission mechanism 30 at the upper limit value α. Although shown, it is not limited to this. For example, if the required vehicle G calculated from the accelerator opening APO occurs before the target variator speed ratio during the inertia phase reaches the upper limit regulation value α, the target variator speed ratio is maintained at the value at that time.
The “request vehicle G” is a target vehicle acceleration that is a predetermined time after a drive power request time point (a change time point of the accelerator opening APO) according to a drive power request from a driver. This “predetermined time” is set to be shorter as the change speed of the accelerator opening APO (depression speed of the accelerator pedal) is larger.

  In the first and second embodiments, an example is shown in which a two-speed forward and one-reverse speed transmission mechanism is applied as the auxiliary transmission mechanism 30, but the invention is not limited to this. The transmission mechanism may be any transmission mechanism that can switch between a plurality of shift speeds by engaging and releasing a plurality of fastening elements, and may be, for example, three forward speeds or four forward speeds. In this case, the present control (when the target variator gear ratio during the inertia phase in the downshift is set to “cooperative shift”) is performed not only at the time of the 2 → 1 downshift but also at the time of the 3 → 2 downshift or the 4 → 3 downshift. Is set to a value greater than the value of

1 engine (driving drive source)
4 Continuously variable transmission (transmission)
7 drive wheels 12 transmission controller (shift control means)
20 Variator (stepless speed change mechanism)
21 Primary pulley 22 Secondary pulley 23 V-belt 30 Sub transmission mechanism (stepped transmission mechanism)
32 Low brake (friction fastening element)
33 High clutch (friction fastening element)

Claims (5)

A variator interposed between the traveling drive source and the drive wheels and capable of changing the gear ratio steplessly;
A stepped sub-transmission mechanism that is provided in a drive system in which the variator is interposed and that can switch a plurality of shift speeds by fastening and releasing a plurality of fastening elements;
When a shift is requested, the speed ratio of the variator is controlled in accordance with the speed ratio of the subtransmission mechanism so that the through speed ratio, which is the overall speed ratio achieved by the variator and the subtransmission mechanism, follows a target value. Shift control means for performing a coordinated shift,
In the control device of the continuously variable transmission having
The shift control means may be configured to, when downshifting the subtransmission mechanism based on a driving force request of a driver, change the speed ratio of the variator during the inertia phase in the downshift and after the inertia phase is completed, by the cooperative speed change. set to a value larger than the speed ratio of the variator to be set when performing,
A control device for a continuously variable transmission , wherein, when the driver operates the accelerator after completion of the inertia phase, the speed ratio of the variator is returned to a value set when the cooperative shift is performed . A variator interposed between the traveling drive source and the drive wheels and capable of changing the gear ratio steplessly;
A stepped sub-transmission mechanism that is provided in a drive system in which the variator is interposed and that can switch a plurality of shift speeds by fastening and releasing a plurality of fastening elements;
When a shift is requested, the speed ratio of the variator is controlled in accordance with the speed ratio of the subtransmission mechanism so that the through speed ratio, which is the overall speed ratio achieved by the variator and the subtransmission mechanism, follows a target value. Shift control means for performing a coordinated shift,
In the control device of the continuously variable transmission having
The shift control means sets a speed ratio of the variator during an inertia phase in the downshift when performing the cooperative shift when downshifting the subtransmission mechanism based on a driving force request of a driver. Set to a value larger than the speed ratio of the variator ,
A control device for a continuously variable transmission, wherein the speed ratio of the variator is returned to a value set when the cooperative shift is performed before the inertia phase is completed . The control device for a continuously variable transmission according to claim 2 ,
The control device for a continuously variable transmission, wherein the shift control means returns the speed ratio of the variator to a value set when the cooperative shift is performed, when the inertia phase in the downshift is completed. . The control device for a continuously variable transmission according to any one of claims 1 to 3 ,
The speed change control means sets a speed ratio of the variator during an inertia phase in the downshift to a value obtained by dividing the through speed ratio by a speed ratio of the subtransmission mechanism before the downshift. Control device for continuously variable transmission. The control device for a continuously variable transmission according to any one of claims 1 to 4 ,
The control device for a continuously variable transmission, wherein the shift control unit sets an upper limit value for a speed ratio of the variator during an inertia phase in the downshift.