JP6881291B2 - Control device for vehicle power transmission device - Google Patents

Description

The present invention relates to a control device for a vehicle power transmission device having a plurality of power transmission paths provided in parallel between a power source and a drive wheel.

A first power transmission path via a gear mechanism having a gear stage provided in parallel between an input rotating member through which the power of the power source is transmitted and an output rotating member that outputs the power to the drive wheels, and the above. It is provided with a plurality of power transmission paths with a second power transmission path via a stepless speed change mechanism in which a gear ratio higher than that of the first power transmission path is formed, and the first power transmission path is first engaged. The second power transmission path is formed by the engagement of the devices, and the second power transmission path is formed by the engagement of the second engagement device provided on the drive wheel side of the stepless speed change mechanism. Is well known. For example, the vehicle control device described in Patent Document 1 is that. In Patent Document 1, a first vehicle is provided in parallel with a gear mechanism in which one gear stage is formed and a continuously variable transmission mechanism in which a transmission element is wound between a primary pulley and a secondary pulley. When switching from the state in which the first power transmission path is formed to the state in which the second power transmission path is formed by the stepped speed change control by the release of the engaging device and the engagement of the second engaging device, the continuously variable transmission mechanism It is disclosed that the shift control of the above is repeatedly executed.

The gear ratio is "rotational speed of the rotating member on the input side / rotational speed of the rotating member on the output side". For example, the gear ratio of the continuously variable transmission mechanism is "rotational speed of the primary pulley / rotational speed of the secondary pulley". The gear ratio of the vehicle power transmission device is "rotational speed of the input rotating member / rotational speed of the output rotating member". The high side in the gear ratio is the high vehicle speed side on which the gear ratio becomes smaller. The low side in the gear ratio is the low vehicle speed side on which the gear ratio becomes large. For example, the lowest gear ratio is the gear ratio on the lowest vehicle speed side, which is the lowest vehicle speed side, and is the maximum gear ratio at which the gear ratio is the largest value.

International Publication No. 2014/170960

By the way, in a vehicle provided with a general stepped automatic transmission, stepped speed change control is executed between two gears having a fixed gear ratio. Even in a vehicle having a first power transmission path via a gear mechanism and a second power transmission path via a continuously variable transmission mechanism in parallel, in consideration of controllability, the state in which the first power transmission path is formed and the first A gear mechanism that switches the stepped speed change control of the power transmission device for vehicles by switching the operating state of the first engaging device and the operating state of the second engaging device, which switches between the states in which the two power transmission paths are formed. It is desirable to execute between the gear ratio of the above and the gear ratio of the predetermined continuously variable transmission mechanism. For example, the stepped speed change control of the power transmission device for a vehicle is executed only when the speed change ratio of the stepless speed change mechanism is the lowest gear ratio. Therefore, when the speed change control of the vehicle power transmission device is executed, if the speed change ratio of the stepless speed change mechanism is higher than the lowest speed side gear ratio, first, the gear ratio of the stepless speed change mechanism is set to the lowest side. Since the downshift as the gear ratio is executed and then the stepped shift control is executed, the stepped shift control is a power-on downshift determined as the drive request amount such as the accelerator operation amount increases. In some cases, the driver may feel a delay in the response of the driving force. Therefore, when the stepped speed change control of the vehicle power transmission device is power on / down shift, the gear ratio of the continuously variable transmission mechanism is not the lowest gear ratio in order to improve the acceleration response. However, it is conceivable to execute the power-on-downshift and, at the same time, execute the lap-down control for downshifting so that the gear ratio of the continuously variable transmission mechanism is the lowest gear ratio. In such a case, the torque input to the second engaging device via the continuously variable transmission mechanism is different from that at the lowest gear ratio. Then, in the hydraulic control that releases the second engaging device assuming the lowest gear ratio, there is a possibility that the power-on-downshift cannot be properly advanced.

The present invention has been made in the context of the above circumstances, and an object of the present invention is to provide a power transmission device for a vehicle capable of appropriately advancing a power-on-downshift when performing lap-down control. The purpose is to provide a control device.

The gist of the first invention is (a) the power provided in parallel between an input rotating member through which the power of the power source is transmitted and an output rotating member that outputs the power to the drive wheels. A plurality of power transmission paths capable of being transmitted from the input rotating member to the output rotating member are provided, and the plurality of power transmission paths include a first power transmission path via a gear mechanism having a gear stage and the said. It has a second power transmission path via a stepless speed change mechanism in which a gear ratio on the higher side than the first power transmission path is formed, and the first power transmission path is the first power transmission path. The second power transmission path is formed by the engagement of the first engaging device provided, and the second power transmission path of the second engaging device provided on the drive wheel side of the stepless speed change mechanism in the second power transmission path. A control device for a vehicle power transmission device formed by engagement, wherein (b) the second engagement device is controlled by stepped speed change control by releasing the second engagement device and engaging the first engagement device. At the time of power-on downshift in which the downshift of the vehicle power transmission device for switching from the state in which the power transmission path is formed to the state in which the first power transmission path is formed is executed as the drive request amount increases, the above-mentioned none. When the gear ratio of the gear shift mechanism is not the lowest gear ratio, the lap-down control is executed by repeatedly downshifting the stepless gear shift mechanism having the gear ratio of the stepless gear shift mechanism as the lowest gear ratio. (C) The shift control unit of the stepless speed change mechanism at the start of the power-on-downshift at the time of the power-on-downshift when executing the wrap-down control. The engagement pressure of the second engaging device, which is reduced so as to advance the power-on-down shift based on the gear ratio, is the basic engagement of the second engaging device when the wrap-down control is not executed. When the rotational speed of the input rotating member approaches the synchronous rotation speed after the end of the power on / down shift while compensating for the combined pressure, if the inclination of the rotational speed of the input rotating member is large, the inclination becomes large. The purpose is to increase the engaging pressure of the second engaging device as compared with the case where it is smaller.

According to the first invention, at the time of power-on-downshift when executing the wrap-down control, the engagement of the second engaging device is based on the gear ratio of the stepless speed change mechanism at the start of the power-on-downshift. Since the pressure is corrected for the basic engaging pressure of the second engaging device when the wrap-down control is not executed, the torque input to the second engaging device via the stepless speed change mechanism is on the lowest side. Even if the gear ratio is different from that of the gear ratio, the second engaging device may start to slide at the target timing. In addition, when the rotational speed of the input rotating member approaches the synchronous rotational speed after the end of the power-on downshift, if the inclination of the rotational speed of the input rotating member is large, the second engagement is higher than when the inclination is small. Since the engagement pressure of the device is increased, even if the progress of the power-on downshift is affected by the downshift of the stepless speed change mechanism, the change in the rotation speed of the input rotating member can be stabilized, that is, stable power-on. You can downshift. Therefore, the power-on-downshift when executing the wrap-down control can be appropriately advanced.

It is a figure explaining the schematic structure of the vehicle to which this invention is applied, and also is the figure explaining the main part of the control function and the control system for various control in a vehicle. It is a flowchart explaining the main part of the control operation of an electronic control device, that is, the control operation for appropriately advancing the power-on-downshift when executing the wrap-down control. It is a figure which shows an example of the time chart when the control operation shown in the flowchart of FIG. 2 is executed.

In the embodiment of the present invention, the continuously variable transmission is a belt-type continuously variable transmission in which a transmission element is wound between a primary pulley and a secondary pulley. The primary pulley, which is a pulley on the input side, and the secondary pulley, which is a pulley on the output side, have thrusts for changing the groove width between, for example, fixed sheaves and movable sheaves and their fixed sheaves and movable sheaves, respectively. It has a hydraulic actuator to be applied. The vehicle provided with the vehicle power transmission device includes a hydraulic control circuit that independently controls the pulley oil pressure as the operating hydraulic pressure supplied to the hydraulic actuator. This hydraulic control circuit may be configured to result in pulley oil pressure by controlling the flow rate of hydraulic oil to the hydraulic actuator, for example. By controlling each thrust (= pulley oil pressure × pressure receiving area) in the primary pulley and the secondary pulley by such a hydraulic control circuit, the target is prevented from slipping of the transmission element of the continuously variable transmission mechanism. The shift control is executed so that the shift is realized. The transmission element wound between the primary pulley and the secondary pulley is an endless annular hoop and an element which is a thick plate piece-like block connected in a large number in the thickness direction along the hoop. An endless annular compression type transmission belt, or a tension type transmission belt in which the ends of alternately stacked link plates are connected to each other by connecting pins to form an endless annular link chain. The continuously variable transmission mechanism is a known belt-type continuously variable transmission. In a broad sense, the concept of this belt-type continuously variable transmission includes a chain-type continuously variable transmission.

Further, the power source is, for example, an engine such as a gasoline engine or a diesel engine that generates power by burning fuel. Further, the vehicle may be provided with an electric motor or the like as the power source in addition to or in place of the engine.

Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram for explaining a schematic configuration of a vehicle 10 to which the present invention is applied, and is a diagram for explaining a control function and a main part of a control system for various controls in the vehicle 10. In FIG. 1, the vehicle 10 includes an engine 12 that functions as a power source, drive wheels 14, and a vehicle power transmission device 16 provided in a power transmission path between the engine 12 and the drive wheels 14. .. Hereinafter, the vehicle power transmission device 16 is referred to as a power transmission device 16.

The power transmission device 16 is connected to a known torque converter 20 as a fluid transmission device connected to the engine 12, an input shaft 22 connected to the torque converter 20, and an input shaft 22 in the case 18 as a non-rotating member. A gear mechanism provided in parallel with the stepless speed change mechanism 24 connected to the input shaft 22 via the stepless speed change mechanism 24, the forward / reverse speed changer 26 also connected to the input shaft 22, and the forward / backward speed changer 26. 28, a deceleration consisting of a pair of gears that are provided in a relative non-rotatable manner and mesh with each other on the output shaft 30, the counter shaft 32, the output shaft 30 and the counter shaft 32, which are common output rotating members of the stepless speed change mechanism 24 and the gear mechanism 28. The gear device 34, the gear 36 provided on the counter shaft 32 so as not to rotate relative to each other, the differential gear 38 connected to the gear 36, and the like are provided. Further, the power transmission device 16 includes left and right axles 40 connected to the differential gear 38. The input shaft 22 is an input rotating member to which the power of the engine 12 is transmitted. The output shaft 30 is an output rotating member that outputs the power of the engine 12 to the drive wheels 14. Unless otherwise specified, the above-mentioned power agrees with torque and force.

In the power transmission device 16 configured in this way, the power output from the engine 12 sequentially passes through the torque converter 20, the forward / backward switching device 26, the gear mechanism 28, the reduction gear device 34, the differential gear 38, the axle 40, and the like. , Is transmitted to the left and right drive wheels 14. Alternatively, in the power transmission device 16, the power output from the engine 12 is transmitted to the left and right drive wheels 14 in sequence via the torque converter 20, the continuously variable transmission mechanism 24, the reduction gear device 34, the differential gear 38, the axle 40, and the like. Will be done.

As described above, the power transmission device 16 includes a gear mechanism 28 and a continuously variable transmission mechanism 24 provided in parallel with the power transmission path PT between the engine 12 and the drive wheels 14. Specifically, the power transmission device 16 includes a gear mechanism 28 and a continuously variable transmission mechanism 24 provided in parallel with the power transmission path PT between the input shaft 22 and the output shaft 30. That is, the power transmission device 16 is provided in parallel between the input shaft 22 and the output shaft 30, and is capable of transmitting the power of the engine 12 from the input shaft 22 to the output shaft 30. It has. The plurality of power transmission paths include a first power transmission path PT1 via a gear mechanism 28 and a second power transmission path PT2 via a continuously variable transmission mechanism 24. That is, the power transmission device 16 includes a plurality of power transmission paths of the first power transmission path PT1 and the second power transmission path PT2 in parallel between the input shaft 22 and the output shaft 30. The first power transmission path PT1 is a power transmission path for transmitting the power of the engine 12 from the input shaft 22 to the drive wheels 14 via the gear mechanism 28. The second power transmission path PT2 is a power transmission path for transmitting the power of the engine 12 from the input shaft 22 to the drive wheels 14 via the continuously variable transmission mechanism 24.

In the power transmission device 16, the power transmission path for transmitting the power of the engine 12 to the drive wheels 14 is switched between the first power transmission path PT1 and the second power transmission path PT2 according to the traveling state of the vehicle 10. Therefore, the power transmission device 16 includes a plurality of engagement devices that selectively form the first power transmission path PT1 and the second power transmission path PT2. The plurality of engaging devices include a first clutch C1, a first brake B1, and a second clutch C2. The first clutch C1 is provided in the first power transmission path PT1 and is an engaging device that selectively connects or disconnects the first power transmission path PT1 and is engaged when moving forward. This is the first engaging device that forms the first power transmission path PT1. The first brake B1 is provided in the first power transmission path PT1 and is an engaging device that selectively connects or disconnects the first power transmission path PT1 and is engaged when moving backward. This is an engaging device that forms the first power transmission path PT1. The first power transmission path PT1 is formed by engaging the first clutch C1 or the first brake B1. The second clutch C2 is provided in the second power transmission path PT2, and is an engaging device that selectively connects or disconnects the second power transmission path PT2. 2 This is a second engaging device that forms the power transmission path PT2. The second power transmission path PT2 is formed by engaging the second clutch C2. The first clutch C1, the first brake B1, and the second clutch C2 are all known hydraulic wet friction engagement devices that are frictionally engaged by a hydraulic actuator. Each of the first clutch C1 and the first brake B1 is one of the elements constituting the forward / backward switching device 26, as will be described later.

The engine 12 includes an engine control device 42 having various devices necessary for controlling the output of the engine 12, such as an electronic throttle device, a fuel injection device, and an ignition device. The engine 12 is engineed by controlling the engine control device 42 according to the accelerator operation amount θacc, which is the operation amount of the accelerator pedal corresponding to the drive request amount for the vehicle 10 by the driver, by the electronic control device 90 described later. The torque Te is controlled.

The torque converter 20 includes a pump impeller 20p connected to the engine 12 and a turbine impeller 20t connected to the input shaft 22. The power transmission device 16 includes a mechanical oil pump 44 connected to a pump impeller 20p. The oil pump 44 is rotationally driven by the engine 12 to control the speed of the continuously variable transmission mechanism 24, generate a belt pinching pressure in the continuously variable transmission mechanism 24, and engage with each of the plurality of engaging devices. The main pressure of the operating hydraulic pressure for switching the operating state such as fitting and releasing is supplied to the hydraulic control circuit 46 provided in the vehicle 10.

The forward / backward switching device 26 includes a double pinion type planetary gear device 26p, a first clutch C1, and a first brake B1. The planetary gear device 26p is a differential mechanism having three rotating elements, a carrier 26c as an input element, a sun gear 26s as an output element, and a ring gear 26r as a reaction force element. The carrier 26c is connected to the input shaft 22. The ring gear 26r is selectively coupled to the case 18 via the first brake B1. The sun gear 26s is connected to a small diameter gear 48 provided around the input shaft 22 so as to be coaxially rotatable relative to the input shaft 22. The carrier 26c and the sun gear 26s are selectively connected via the first clutch C1.

The gear mechanism 28 has a small diameter gear 48, a gear mechanism counter shaft 50, and a large diameter that is provided around the gear mechanism counter shaft 50 so as to be coaxially non-rotatable with respect to the gear mechanism counter shaft 50 and meshes with the small diameter gear 48. It is equipped with a gear 52. The large-diameter gear 52 has a larger diameter than the small-diameter gear 48. Further, the gear mechanism 28 is coaxial with the idler gear 54 provided around the gear mechanism counter shaft 50 so as to be rotatable relative to the gear mechanism counter shaft 50 and about the output shaft 30 with respect to the output shaft 30. It is provided with an output gear 56 which is provided in the center so as not to rotate relative to the center and meshes with the idler gear 54. The output gear 56 has a larger diameter than the idler gear 54. Therefore, in the gear mechanism 28, one gear stage is formed in the power transmission path PT between the input shaft 22 and the output shaft 30. The gear mechanism 28 is a gear mechanism having a gear stage. The gear mechanism 28 is further provided around the gear mechanism counter shaft 50 between the large-diameter gear 52 and the idler gear 54, and meshes to selectively connect or disconnect the power transmission path between them. The type clutch D1 is provided. The meshing clutch D1 is an engaging device that selectively connects or disconnects the first power transmission path PT1 and forms the first power transmission path PT1 by being engaged. is there. The meshing clutch D1 is an engaging device that forms a first power transmission path PT1 by being engaged with the first clutch C1 or the first brake B1, and is included in the plurality of engaging devices. The operating state of the meshing clutch D1 is switched by the operation of a hydraulic actuator (not shown) provided in the power transmission device 16.

The first power transmission path PT1 is formed by engaging both the meshing clutch D1 and the first clutch C1 or the first brake B1 provided on the input shaft 22 side of the meshing clutch D1. .. The engagement of the first clutch C1 forms a power transmission path for forward movement, while the engagement of the first brake B1 forms a power transmission path for reverse movement. When the first power transmission path PT1 is formed, the power transmission device 16 is in a power transmission capable state in which the power of the engine 12 can be transmitted from the input shaft 22 to the output shaft 30 via the gear mechanism 28. .. On the other hand, the first power transmission path PT1 is put into a neutral state in which power transmission is impossible when both the first clutch C1 and the first brake B1 are released or when the meshing clutch D1 is released.

The continuously variable transmission mechanism 24 includes a primary shaft 58 which is provided coaxially with the input shaft 22 and is integrally connected to the input shaft 22, a primary pulley 60 which is connected to the primary shaft 58 and has a variable effective diameter, and an output. A secondary shaft 62 provided coaxially with the shaft 30, a secondary pulley 64 connected to the secondary shaft 62 having a variable effective diameter, and a transmission belt as a transmission element wound between the pulleys 60 and 64, respectively. It has 66. The continuously variable transmission mechanism 24 is a known belt-type continuously variable transmission in which power is transmitted via frictional force between the pulleys 60 and 64 and the transmission belt 66, and the power of the engine 12 is driven by the drive wheels 14. Communicate to the side. The frictional force agrees with the pinching pressure, and is also referred to as a belt pinching pressure. The belt pinching pressure is the belt torque capacity Tcvt, which is the torque capacity of the transmission belt 66 in the continuously variable transmission mechanism 24.

The primary pulley 60 includes a fixed sheave 60a connected to the primary shaft 58, a movable sheave 60b provided so as to be non-rotatable relative to the axis of the primary shaft 58 and movable in the axial direction with respect to the fixed sheave 60a. It is provided with a hydraulic actuator 60c that applies a primary thrust Wpri to the movable sheave 60b. The primary thrust Wpri is the thrust (= primary pressure Ppri × pressure receiving area) of the primary pulley 60 for changing the V-groove width between the fixed sheave 60a and the movable sheave 60b. That is, the primary thrust Wpri is the thrust of the primary pulley 60 that clamps the transmission belt 66 applied by the hydraulic actuator 60c. The primary pressure Ppri is the hydraulic pressure supplied to the hydraulic actuator 60c by the hydraulic control circuit 46, and is the pulley hydraulic pressure that produces the primary thrust Wpri. Further, the secondary pulley 64 is provided with a fixed sheave 64a connected to the secondary shaft 62 and a movable sheave 64b provided so as to be non-rotatable relative to the fixed sheave 64a around the axis of the secondary shaft 62 and movable in the axial direction. And a hydraulic actuator 64c that applies a secondary thrust Wsec to the movable sheave 64b. The secondary thrust Wsec is the thrust (= secondary pressure Psec × pressure receiving area) of the secondary pulley 64 for changing the V-groove width between the fixed sheave 64a and the movable sheave 64b. That is, the secondary thrust Wsec is the thrust of the secondary pulley 64 that clamps the transmission belt 66 applied by the hydraulic actuator 64c. The secondary pressure Psec is the hydraulic pressure supplied to the hydraulic actuator 64c by the hydraulic control circuit 46, and is the pulley hydraulic pressure that causes the secondary thrust Wsec.

In the continuously variable transmission mechanism 24, the primary pressure Ppri and the secondary pressure Psec are controlled by the hydraulic control circuit 46 driven by the electronic control device 90 described later, so that the primary thrust Wpri and the secondary thrust Wsec are controlled respectively. To. As a result, in the continuously variable transmission mechanism 24, the V-groove widths of the pulleys 60 and 64 are changed to change the hook diameter (= effective diameter) of the transmission belt 66, and the gear ratio γcvt (= primary rotation speed Npri / secondary rotation) is changed. The speed Nsec) is changed, and the belt pinching pressure is controlled so that the transmission belt 66 does not slip. That is, by controlling the primary thrust Wpri and the secondary thrust Wsec, respectively, the speed change ratio γcvt of the continuously variable transmission mechanism 24 is set as the target speed change ratio γcvtt while the belt slippage, which is the slippage of the transmission belt 66, is prevented. The primary rotation speed Npri is the rotation speed of the primary shaft 58, and the secondary rotation speed Nsec is the rotation speed of the secondary shaft 62.

In the continuously variable transmission mechanism 24, when the primary pressure Ppri is increased, the V-groove width of the primary pulley 60 is narrowed and the gear ratio γcvt is reduced. The reduction of the gear ratio γcvt means that the continuously variable transmission mechanism 24 is upshifted. In the continuously variable transmission mechanism 24, the highest gear ratio γmin is formed where the V-groove width of the primary pulley 60 is minimized. The highest gear ratio γmin is the gear ratio γcvt on the highest vehicle speed side, which is the highest vehicle speed side in the range of the gear ratio γcvt formed by the continuously variable transmission mechanism 24, and the gear ratio γcvt is the smallest value. The minimum gear ratio. On the other hand, in the continuously variable transmission mechanism 24, when the primary pressure Ppri is lowered, the V-groove width of the primary pulley 60 is widened and the gear ratio γcvt is increased. Increasing the gear ratio γcvt means that the continuously variable transmission mechanism 24 is downshifted. In the continuously variable transmission mechanism 24, the lowest gear ratio γmax is formed where the V-groove width of the primary pulley 60 is maximized. The lowest gear ratio γmax is the gear ratio γcvt on the lowest vehicle speed side, which is the lowest vehicle speed side in the range of the gear ratio γcvt formed by the continuously variable transmission mechanism 24, and the gear ratio γcvt is the largest value. Maximum gear ratio. In the continuously variable transmission mechanism 24, the belt slip is prevented by the primary thrust Wpri and the secondary thrust Wsec, and the target gear ratio γcvtt is realized by the mutual relationship between the primary thrust Wpri and the secondary thrust Wsec. The target shift cannot be achieved with only one thrust. Due to the mutual relationship between the primary pressure Ppri and the secondary pressure Psec, the thrust ratio τ (= Wsec / Wpri), which is the ratio between the primary thrust Wpri and the secondary thrust Wsec, is changed, so that the gear ratio γcvt of the continuously variable transmission mechanism 24 is changed. Be changed. The thrust ratio τ is a value of the ratio of the secondary thrust Wsec to the primary thrust Wpri. For example, as the thrust ratio τ increases, the gear ratio γcvt increases, that is, the continuously variable transmission mechanism 24 is downshifted.

The output shaft 30 is arranged so as to be rotatable relative to the secondary shaft 62 on the same axis. The second clutch C2 is provided in the power transmission path between the secondary pulley 64 and the output shaft 30. That is, the second clutch C2 is provided on the drive wheel 14 side of the continuously variable transmission mechanism 24 in the second power transmission path PT2. The second power transmission path PT2 is formed by engaging the second clutch C2. In the power transmission device 16, when the second power transmission path PT2 is formed, the power of the engine 12 can be transmitted from the input shaft 22 to the output shaft 30 via the continuously variable transmission mechanism 24. Will be done. On the other hand, the second power transmission path PT2 is put into the neutral state when the second clutch C2 is released. The gear ratio γcvt of the continuously variable transmission mechanism 24 corresponds to the gear ratio in the second power transmission path PT2.

In the power transmission device 16, the gear ratio EL of the gear mechanism 28, which is the gear ratio γ gear (= input shaft rotation speed Nin / output shaft rotation speed Nout) in the first power transmission path PT1, is the maximum gear shift in the second power transmission path PT2. The ratio is set to a value larger than the lowest speed change ratio γmax of the stepless speed change mechanism 24. That is, the gear ratio EL is set to a gear ratio on the low side of the lowest gear ratio γmax. The gear ratio EL of the gear mechanism 28 corresponds to the first speed gear ratio γ1 in the power transmission device 16, and the lowest gear ratio γmax of the continuously variable transmission mechanism 24 corresponds to the second speed gear ratio γ2 in the power transmission device 16. Equivalent to. In this way, the second power transmission path PT2 is formed with a gear ratio on the higher side than the first power transmission path PT1. The input shaft rotation speed Nin is the rotation speed of the input shaft 22, and the output shaft rotation speed Nout is the rotation speed of the output shaft 30.

In the vehicle 10, it is possible to selectively perform traveling in the gear traveling mode and traveling in the belt traveling mode. The gear traveling mode is a traveling mode in which the vehicle travels using the first power transmission path PT1 and is in a state in which the first power transmission path PT1 is formed in the power transmission device 16. The belt traveling mode is a traveling mode in which the vehicle travels using the second power transmission path PT2, and is a traveling mode in which the second power transmission path PT2 is formed in the power transmission device 16. In the gear traveling mode, the first clutch C1 and the meshing clutch D1 are engaged and the second clutch C2 and the first brake B1 are released when the forward traveling is possible. In the gear traveling mode, the first brake B1 and the meshing clutch D1 are engaged and the second clutch C2 and the first clutch C1 are released when the reverse traveling is possible. In the belt traveling mode, the second clutch C2 is engaged and the first clutch C1 and the first brake B1 are released. In this belt running mode, forward running is possible.

The gear running mode is selected in a relatively low vehicle speed region, including when the vehicle is stopped. The belt travel mode is selected in a relatively high vehicle speed region including a medium vehicle speed region. The meshing clutch D1 is engaged in the belt travel mode in the medium vehicle speed region of the belt travel mode, while the mesh clutch D1 is released in the belt travel mode in the high vehicle speed region of the belt travel mode. .. The meshing clutch D1 is released in the belt traveling mode in the high vehicle speed region, for example, by eliminating the drag of the gear mechanism 28 or the like during traveling in the belt traveling mode, and at high vehicle speed, the gear mechanism 28 or the planetary gear device. This is to prevent the 26p component, for example, a pinion, from rotating at a high speed.

The vehicle 10 includes an electronic control device 90 as a controller including a control device for the power transmission device 16. The electronic control device 90 is configured to include, for example, a so-called microcomputer provided with a CPU, RAM, ROM, an input / output interface, etc., and the CPU follows a program stored in the ROM in advance while using the temporary storage function of the RAM. Various controls of the vehicle 10 are executed by performing signal processing. The electronic control device 90 controls the output of the engine 12, the shift control of the continuously variable transmission mechanism 24, the belt pinching pressure control, and the hydraulic control for switching the operating state of each of the plurality of engaging devices (C1, B1, C2, D1). And so on. The electronic control device 90 is separately configured for engine control, hydraulic control, and the like, if necessary.

The electronic control device 90 includes various sensors provided in the vehicle 10 (for example, various rotation speed sensors 70, 72, 74, 76, accelerator operation amount sensor 78, throttle opening sensor 80, shift position sensor 82, etc.). Detection signals, etc. (for example, engine rotation speed Ne, primary rotation speed Npri which is the same value as input shaft rotation speed Nin, secondary rotation speed Nsec, output shaft rotation speed Nout corresponding to vehicle speed V, magnitude of driver's acceleration operation The accelerator operation amount θacc, the throttle opening tap, the operation position POSsh of the shift lever 84 provided in the vehicle 10, etc.) are supplied respectively. Further, from the electronic control device 90, various command signals (for example, engine control command signal Se for controlling the engine 12) are transmitted to each device (for example, engine control device 42, hydraulic control circuit 46, etc.) provided in the vehicle 10. The hydraulic control command signal Scvt for controlling the speed change of the speed change mechanism 24, the belt pinching pressure, etc., the hydraulic control command signal Scbd for controlling the operating state of each of the plurality of engaging devices, etc.) are output. Ru. The input shaft rotation speed Nin (= primary rotation speed Npri) is also the turbine rotation speed, the primary rotation speed Npri is also the rotation speed of the primary pulley 60, and the secondary rotation speed Nsec is the rotation speed of the secondary pulley 64. But also. Further, the electronic control device 90 calculates the actual gear ratio γcvt (= Npri / Nsec), which is the actual gear ratio γcvt of the continuously variable transmission mechanism 24, based on the primary rotation speed Npri and the secondary rotation speed Nsec. Further, the hydraulic control command signal Scbd is, for example, the engaging pressure of each engaging device such as the first clutch C1 and the second clutch C2, and each solenoid valve that regulates each engaging hydraulic pressure supplied to each hydraulic actuator. It is a command signal for driving etc. The electronic control device 90 sets a hydraulic pressure instruction value corresponding to each engagement hydraulic pressure value for obtaining the target torque capacity of each engagement device, and hydraulically controls the drive current or drive voltage according to the hydraulic pressure instruction value. Output to circuit 46.

The operation position POSsh of the shift lever 84 is, for example, a P, R, N, D operation position. The P operation position is a parking operation position that selects the P position of the power transmission device 16 in which the power transmission device 16 is in the neutral state and the output shaft 30 is mechanically fixed so as not to rotate. The neutral state of the power transmission device 16 is realized, for example, by releasing the first clutch C1, the first brake B1, and the second clutch C2. That is, the neutral state of the power transmission device 16 is a state in which neither the first power transmission path PT1 nor the second power transmission path PT2 is formed. The R operation position is a reverse travel operation position that selects the R position of the power transmission device 16 that enables reverse travel in the gear travel mode. The N operation position is a neutral operation position that selects the N position of the power transmission device 16 in which the power transmission device 16 is in the neutral state. The D operation position is the D of the power transmission device 16 that enables forward traveling in the gear traveling mode or executes automatic shift control of the continuously variable transmission mechanism 24 in the belt traveling mode to enable forward traveling. It is a forward running operation position that selects a position.

The electronic control device 90 includes an engine control means, that is, an engine control unit 92, a shift control means, that is, a shift control unit 94, and a state determination means, that is, a state determination unit 96, in order to realize various controls in the vehicle 10.

The engine control unit 92 applies the accelerator operation amount θacc and the vehicle speed V to, for example, a driving force map, which is a relationship that is experimentally or designedly obtained and stored, that is, a predetermined relationship, so that the required driving force Fdem Is calculated. The engine control unit 92 sets a target engine torque Tet from which the required driving force Fdem can be obtained, and outputs an engine control command signal Se that controls the engine 12 so that the target engine torque Tet can be obtained to the engine control device 42. ..

When the operation position POSsh is in the P operation position or the N operation position while the vehicle is stopped, the shift control unit 94 engages with the meshing clutch D1 in preparation for the shift to the gear traveling mode. The Scbd is output to the hydraulic control circuit 46. When the operation position POSsh is changed from the P operation position or the N operation position to the D operation position while the vehicle is stopped, the shift control unit 94 sends the hydraulic control command signal Scbd that engages the first clutch C1 to the hydraulic control circuit 46. Output. As a result, the traveling mode is shifted to the gear traveling mode that enables forward traveling. When the operation position POSsh is changed from the P operation position or the N operation position to the R operation position while the vehicle is stopped, the shift control unit 94 sends the hydraulic control command signal Scbd that engages the first brake B1 to the hydraulic control circuit 46. Output. As a result, the traveling mode is shifted to the gear traveling mode that enables reverse traveling.

When the operation position POSsh is the D operation position, the shift control unit 94 executes switching control for switching between the gear travel mode and the belt travel mode. Specifically, the shift control unit 94 corresponds to the first speed gear corresponding to the gear ratio EL of the gear mechanism 28 in the gear traveling mode and the lowest gear ratio γmax of the stepless shifting mechanism 24 in the belt traveling mode. The vehicle speed V and the accelerator operation amount θacc are applied to the upshift line and the downshift line as the stepped shift map, which has a predetermined relationship and has a predetermined hysteresis for switching to the second speed shift stage. By doing so, the necessity of shifting is determined, and the traveling mode is switched based on the determination result.

When the shift control unit 94 determines upshift during traveling in the gear traveling mode and switches to the belt traveling mode, the clutch that releases the first clutch C1 and re-grasps the clutch so as to engage the second clutch C2. The hydraulic control command signal Scbd for shifting the clutch is output to the hydraulic control circuit 46. As a result, the power transmission path PT in the power transmission device 16 is switched from the first power transmission path PT1 to the second power transmission path PT2. As described above, the shift control unit 94 is changed from the gear traveling mode in which the first power transmission path PT1 is formed by the stepped shift control by the release of the first clutch C1 and the engagement of the second clutch C2. 2 The upshift of the power transmission device 16 for switching to the belt traveling mode in which the power transmission path PT2 is formed is executed. In this embodiment, the upshift of the power transmission device 16 that switches from the gear traveling mode to the belt traveling mode is referred to as a stepped upshift.

When the shift control unit 94 determines the downshift during traveling in the belt traveling mode and switches to the gear traveling mode, the clutch that releases the second clutch C2 and re-grasps the clutch so as to engage the first clutch C1. The hydraulic control command signal Scbd that performs the two-clutch shift is output to the hydraulic control circuit 46. As a result, the power transmission path PT in the power transmission device 16 is switched from the second power transmission path PT2 to the first power transmission path PT1. As described above, the shift control unit 94 is changed from the belt traveling mode in which the second power transmission path PT2 is formed by the stepped shift control by the release of the second clutch C2 and the engagement of the first clutch C1. 1 The downshift of the power transmission device 16 for switching to the gear traveling mode in which the power transmission path PT1 is formed is executed. In this embodiment, the downshift of the power transmission device 16 that switches from the belt traveling mode to the gear traveling mode is referred to as a stepped downshift.

In the switching control for switching between the gear traveling mode and the belt traveling mode, the torque is transferred by the clutch-to-clutch shift by passing through the state of the belt traveling mode in the medium vehicle speed region in which the meshing clutch D1 is engaged. Since the first power transmission path PT1 and the second power transmission path PT2 can be switched only by itself, the switching shock is suppressed. As described above, the switching control for switching between the gear traveling mode and the belt traveling mode is a stepped speed change control by switching the operating state of the first clutch C1 and switching the operating state of the second clutch C2.

In the belt traveling mode, the speed change control unit 94 sets the primary pressure Ppri and the secondary pressure Psec so as to achieve the target speed change ratio γcvtt of the stepless speed change mechanism 24 while preventing the belt slip of the stepless speed change mechanism 24 from occurring. The hydraulic control command signal Scvt that controls the above is output to the hydraulic control circuit 46 to execute the shifting of the continuously variable transmission mechanism 24.

Specifically, the shift control unit 94 calculates the target primary rotation speed Nprit by applying the accelerator operation amount θacc and the vehicle speed V to, for example, the CVT shift map, which has a predetermined relationship. The shift control unit 94 calculates the target gear ratio γcvtt (= Nprit / Nsec) based on the target primary rotation speed Nprit. The shift control unit 94 calculates an estimated value of the engine torque Te by applying the throttle opening tap and the engine rotation speed Ne to, for example, the engine torque map, which has a predetermined relationship. The shift control unit 94 calculates the turbine torque Tt based on the estimated value of the engine torque Te and the characteristics of, for example, the torque converter 20 which is a predetermined relationship. The shift control unit 94 uses the turbine torque Tt as the primary input torque Tpri, which is the input torque input to the primary pulley 60. The primary input torque Tpri is the torque on the primary shaft 58. The shift control unit 94 calculates the thrust ratio τ for realizing the target gear ratio γcvtt by applying the target gear ratio γcvtt and the torque ratio to the thrust ratio map which is a predetermined relationship. This torque ratio is the ratio (= Tpri / Tprilim) of the calculated primary input torque Tpri and the limit torque Tprilim that can be input to the predetermined primary pulley 60. The shift control unit 94 calculates the target primary thrust Wprit and the target secondary thrust Wsect for achieving this thrust ratio τ. If one thrust is determined, the other thrust is also determined based on the thrust ratio τ for achieving the target gear ratio γcvtt. The shift control unit 94 converts the target primary thrust Wprit and the target secondary thrust Wsect into the target primary pressure Pprit (= Wprit / pressure receiving area) and the target secondary pressure Psect (= Wsect / pressure receiving area), respectively. The shift control unit 94 outputs a hydraulic control command signal Scvt that controls the primary pressure Ppri and the secondary pressure Psec to the hydraulic control circuit 46 so that the target primary pressure Pprit and the target secondary pressure Psect can be obtained. The hydraulic control circuit 46 operates each solenoid valve according to the hydraulic control command signal Scvt to regulate the primary pressure Ppri and the secondary pressure Psec. In the description of the shift control of the continuously variable transmission mechanism 24 described above, for convenience, the thrust for maintaining the target gear ratio γcvtt at a constant level has been described. In the shift transition of the continuously variable transmission mechanism 24, the thrust for achieving the target upshift or the target downshift is added to the thrust for maintaining this constant.

In the calculation of the target primary thrust Wprit and the target secondary thrust Wsect, the required thrust, which is the thrust required to prevent the belt slip of the continuously variable transmission mechanism 24 with the minimum necessary thrust, is taken into consideration. This required thrust is the slip limit thrust, which is the thrust immediately before the belt slip of the continuously variable transmission mechanism 24 occurs.

The shift control unit 94 sets the primary limit thrust Wprilim, which is the limit thrust of the primary pulley 60, and the secondary limit thrust Wseclim, which is the limit thrust of the secondary pulley 64. The shift control unit 94 sets the primary limit thrust Wprilim using the following equation (1). The shift control unit 94 sets the secondary limit thrust Wseclim using the following equation (2). In the following equations (1) and (2), "α" is the sheave angle of each of the pulleys 60 and 64, "μ" is the coefficient of friction between the belt element and the sheave, and "Rpri" is the continuously variable transmission mechanism 24. The belt hook diameter on the primary pulley 60 side calculated based on the gear ratio γcvt of, "γcvt × Tpri" is the torque input to the secondary pulley 64, and "Rsec" is based on the gear ratio γcvt of the continuously variable transmission mechanism 24. The calculated belt hook diameter on the secondary pulley 64 side is shown.

Wprilim = (Tpri × cosα) / (2 × μ × Rpri)… (1)
Wseclim = (γcvt × Tpri × cosα) / (2 × μ × Rsec)… (2)

The shift control unit 94 has a secondary shift control thrust Wsecsh (= τ ×), which is the thrust of the secondary pulley 64 required for shift control, based on the primary limit thrust Wprilim and the thrust ratio τ for achieving the target shift ratio γcvtt. Wprilim) is calculated. The shift control unit 94 sets the larger of the secondary limit thrust Wseclim and the secondary shift control thrust Wsecsh as the target secondary thrust Wsect. The shift control unit 94 calculates the target primary thrust Wprit (= Wsect / τ) based on the target secondary thrust Wsect and the thrust ratio τ for realizing the target shift ratio γcvtt.

Here, in consideration of controllability, the stepped upshift and the stepped downshift, which are the stepped speed change control of the power transmission device 16, are two gears having a fixed gear ratio, like a known stepped transmission. Similar to the stepped speed change control between gears, it is desirable to shift between the gear ratio EL of the gear mechanism 28 and the gear ratio γcvt of the predetermined stepless speed change mechanism 24. In this embodiment, in consideration of suppressing the amount of change in the primary rotation speed Npri during stepped speed change control of the power transmission device 16 or the continuity of the driving force, the predetermined stepless speed change mechanism 24 The gear ratio γcvt is set to the lowest gear ratio γmax, which is the gear ratio γcvt closest to the gear ratio EL of the gear mechanism 28. Suppressing the amount of change in the primary rotation speed Npri leads to suppressing, for example, the amount of heat generated when the second clutch C2 is engaged.

When the stepped downshift of the power transmission device 16 is a power-on-downshift determined as the drive request amount, for example, the accelerator operation amount θacc increases, it is desirable to prioritize acceleration responsiveness over shock suppression. .. Therefore, the shift control unit 94 is in a state where the gear ratio γcvt of the continuously variable transmission mechanism 24 is not the lowest gear ratio γmax when the stepped downshift of the power transmission device 16 is a power-on downshift. But it does a stepped downshift. At this time, the shift control unit 94 controls the gear ratio γcvt of the continuously variable transmission mechanism 24 to be the lowest gear ratio γmax together with the stepped downshift of the power transmission device 16. That is, the shift control unit 94 changes the gear ratio γcvt of the continuously variable transmission mechanism 24 to the lowest gear ratio γmax at the time of power-on-downshift in which the stepped downshift of the power transmission device 16 is executed as the drive request amount increases. If not, the lap-down control is executed by repeatedly downshifting the continuously variable transmission mechanism 24 in which the gear ratio γcvt is set to the lowest gear ratio γmax. In this way, the shift control unit 94 superimposes the stepped downshift of the power transmission device 16 and the downshift of the stepless speed change mechanism 24 in which the speed change ratio γcvt of the stepless speed change mechanism 24 is set to the lowest gear ratio γmax. Execute the wrap-down control to be performed.

When the stepped downshift of the power transmission device 16 is a power-on downshift, assuming that no torque capacity is generated in either the release side engaging device or the engaging side engaging device during shifting, the input shaft rotations. The speed Nin is eventually increased towards the synchronous rotation speed after the end of the power-on-downshift. Therefore, in the power-on-downshift, the shift is mainly carried out by reducing the engagement pressure of the release side engaging device. The release side engaging device is an engaging device on the side that is released at the time of shifting, and corresponds to the second clutch C2 in the stepped downshift of the power transmission device 16. The engaging side engaging device is an engaging device on the side to be engaged at the time of shifting, and corresponds to the first clutch C1 in the stepped downshift of the power transmission device 16. The synchronous rotation speed after the end of the power-on-downshift is the synchronous rotation speed (= γ1 × Nout) in the gear travel mode, and the synchronous rotation speed before the start of the power-on-downshift is the synchronous rotation in the belt travel mode. The speed (= γcvt × Nout).

By the way, at the time of power-on-downshift of the power transmission device 16 when executing the lap-down control, the torque (= γcvt × Tpri) input to the second clutch C2 via the continuously variable transmission mechanism 24 is the lowest shift. The value is different from that when the ratio is γmax.

Therefore, in order to appropriately advance the power-on-downshift of the power transmission device 16 during the lap-down control, the shift control unit 94 sets the actual gear ratio γcvt of the continuously variable transmission mechanism 24 at the shift output of the power-on-downshift. Based on this, the engaging pressure of the second clutch C2 is corrected. The correction of the engagement pressure of the second clutch C2 is mainly from the start of the power-on-downshift to the synchronous rotation speed in the gear travel mode when the input shaft rotation speed Nin leaves the synchronous rotation speed in the belt travel mode. It is done until it starts to rise toward. That is, by correcting the engagement pressure of the second clutch C2 in the first half of the power-on-downshift, the second clutch C2 is surely started to slide within the target time.

Since the progress of the power-on-downshift during lap-down control is affected by the change in the actual gear ratio γcvt of the continuously variable transmission mechanism 24, the progress of the power-on-downshift is controlled by the engagement pressure of the second clutch C2. That is not desirable. Instead of controlling the progress of the power-on-downshift with the engagement pressure of the second clutch C2, when the input shaft rotation speed Nin approaches the synchronous rotation speed in the gear running mode, the inclination of the input shaft rotation speed Nin becomes Based on this, the engagement pressure of the second clutch C2 in the latter half of the power-on-downshift is corrected.

Specifically, when the shift control unit 94 determines or starts the power on / down shift of the power transmission device 16, the state determination unit 96 sets the gear ratio γcvt of the continuously variable transmission mechanism 24 from the predetermined gear ratio γcvtf. Also determines whether or not the gear ratio is on the high side. That is, the state determination unit 96 determines whether or not the gear ratio γcvt of the continuously variable transmission mechanism 24 is less than the predetermined gear ratio γcvtf. The predetermined gear ratio γcvtf is a predetermined threshold value for determining that the gear ratio γcvt of the continuously variable transmission mechanism 24 is not the lowest gear ratio γmax. That is, the predetermined gear ratio γcvtf is a value corresponding to the lowest gear ratio γmax.

When the shift control unit 94 determines that the shift ratio γcvt of the continuously variable transmission mechanism 24 is a value equal to or higher than the predetermined shift ratio γcvtf at the time of power on / down shift of the power transmission device 16, there is no shift control unit 94. While maintaining the gear ratio γcvt of the speed shift mechanism 24 at the lowest gear ratio γmax, normal power-on-downshift control is executed. The normal power-on-downshift control is, for example, a power-on-downshift control at the lowest gear ratio γmax, and is a second clutch at a predetermined lowest gear ratio γmax according to the primary input torque Tpri. This is a control in which the power-on-downshift is advanced by the basic engagement pressure of C2.

When the shift control unit 94 determines that the gear ratio γcvt of the continuously variable transmission mechanism 24 is less than the predetermined gear ratio γcvtf at the time of power on / down shift of the power transmission device 16, there is no shift control unit 94. While executing the downshift in which the gear ratio γcvt of the gear shifting mechanism 24 is set to the lowest gear ratio γmax, the power-on downshift control for wrap-down is executed. The power-on-downshift control for wrap-down is based on, for example, the actual gear ratio γcvt of the continuously variable transmission mechanism 24 at the start of the power-on-downshift, and the basic engagement of the second clutch C2 at the lowest gear ratio γmax. This is a control in which the power on / down shift is executed by the engaging pressure of the second clutch C2 corrected with respect to the pressure. That is, at the time of power-on-downshift when executing the lap-down control, the shift control unit 94 advances the power-on-downshift based on the actual shift ratio γcvt of the continuously variable transmission mechanism 24 at the start of the power-on-downshift. The engagement pressure of the second clutch C2, which is lowered so as to be caused, is corrected with respect to the basic engagement pressure of the second clutch C2 when the wrap-down control is not executed. For example, the shift control unit 94 sets the engagement pressure of the second clutch C2 before and during the gradual decrease, and the shift ratio γcvt of the continuously variable transmission mechanism 24 at the start of the power-on-down shift is the shift ratio on the high side. The correction is made so that the pressure is smaller than the basic engagement pressure of the second clutch C2.

In addition, the power-on-downshift control for wrap-down is the second clutch corrected according to the inclination of the input shaft rotation speed Nin, for example, when the input shaft rotation speed Nin approaches the synchronous rotation speed in the gear running mode. This is a control in which the power-on-downshift is executed by the engagement pressure of C2. The slope of the input shaft rotation speed Nin is the change speed of the input shaft rotation speed Nin, and is the amount of change of the input shaft rotation speed Nin in the control repeatedly executed in a predetermined time. The correction according to the inclination of the input shaft rotation speed Nin applies the engagement pressure of the second clutch C2 in order to keep the change of the input shaft rotation speed Nin, for example, in the vicinity of the synchronous rotation speed in the gear running mode. It is an additional correction, that is, an increasing correction. Retaining the change in the input shaft rotation speed Nin is to reduce the inclination of the input shaft rotation speed Nin. When the inclination of the input shaft rotation speed Nin near the synchronous rotation speed in the gear running mode is relatively large, the amount of addition of the engagement pressure of the second clutch C2 is increased, so that the input shaft rotation speed Nin changes. It is made to act to keep. On the other hand, when the inclination of the input shaft rotation speed Nin near the synchronous rotation speed in the gear traveling mode is relatively small, the additional amount of the engagement pressure of the second clutch C2 is reduced, so that the input shaft rotation speed is reduced. The action of retaining the change in Nin is reduced. As described above, appropriate engagement control of the first clutch C1 can be performed. That is, when the shift control unit 94 has a large inclination of the input shaft rotation speed Nin when the input shaft rotation speed Nin approaches the synchronous rotation speed in the gear traveling mode at the time of power-on-downshift when executing the wrap-down control. Increases the engagement pressure of the second clutch C2 as compared with the case where the inclination is small.

FIG. 2 is a flowchart illustrating a main part of the control operation of the electronic control device 90, that is, a control operation for appropriately advancing the power-on-downshift when executing the wrap-down control. For example, the start of the power-on-downshift. Sometimes executed. FIG. 3 is a diagram showing an example of a time chart when the control operation shown in the flowchart of FIG. 2 is executed.

In FIG. 2, first, in step S10 corresponding to the function of the state determination unit 96, whether or not the gear ratio γcvt of the continuously variable transmission mechanism 24 is less than the predetermined gear ratio γcvtf is determined. It is judged. If the determination in S10 is affirmed, in S20 corresponding to the function of the shift control unit 94, downshifting with the gear ratio γcvt of the continuously variable transmission mechanism 24 as the lowest gear ratio γmax is executed, and the lap down is performed. Power-on-downshift control is executed. If the determination in S10 is denied, in S30 corresponding to the function of the shift control unit 94, normal power-on-downshift control is performed while the gear ratio γcvt of the continuously variable transmission mechanism 24 is maintained at the lowest gear ratio γmax. The power-on-downshift control at the lowest gear ratio γmax is executed.

FIG. 3 shows an example of an embodiment in which a power-on-downshift of the power transmission device 16 with wrap-down control is executed. In FIG. 3, the solid line shows the power-on-downshift control during lap-down. For reference, the hydraulic control reading of the release side engaging device in normal power-on-downshift control is shown by a broken line. Since the power-on downshift is a stepped downshift of the power transmission device 16, the release side engaging device is the second clutch C2, and the engaging side engaging device is the first clutch C1. The time point t1 indicates the time point when the power-on-downshift is started. By the wrap-down control, the synchronous rotation speed in the belt traveling mode is changed toward the synchronous rotation speed at the lowest gear ratio γmax (see time point t1 − time point t4). The input shaft rotation speed Nin is started to increase from the synchronous rotation speed in the belt travel mode to the synchronous rotation speed in the gear travel mode by the power-on-down shift of the continuously variable transmission mechanism 24 (see t1 point-t2 time point). ). In the power-on-downshift hydraulic control at this time, the basic mechanism when the lowest gear ratio γmax, which is the base pressure of the second clutch C2, is used as the hydraulic control value of the second clutch C2 before the start of the gradual decrease, that is, before the start of the sweepdown. The value obtained by multiplying the oil pressure indicated value before the start of sweepdown at the combined pressure by the gear ratio correction term is used. Further, as the oil pressure indicated value of the second clutch C2 at the time of gradual decrease, that is, at the time of sweep down, the sweep gradient at the time of sweep down is the value obtained by multiplying the sweep gradient at the time of gradual decrease at the base pressure of the second clutch C2 by the gear ratio correction term. The given oil pressure reading is used. This gear ratio correction term is set to a value that becomes smaller as the gear ratio γcvt becomes higher, for example, when the gear ratio γmax on the lowest side is set to “1”. In the subsequent power-on-down shift hydraulic control, the hydraulic instruction value of the second clutch C2, which is a sweep-down with a gentler sweep-down than the above-mentioned sweep-down, is output, and the input shaft rotation speed Nin is synchronous rotation in the gear running mode. Raised towards speed (see t2-point-t3). When the input shaft rotation speed Nin approaches the synchronous rotation speed in the gear traveling mode, the oil pressure indicated value of the second clutch C2 is increased by the amount corresponding to the amount of change in the input shaft rotation speed Nin (see time point t3). The larger the amount of change in the input shaft rotation speed Nin, the larger the additional amount of the oil pressure indicated value of the second clutch C2. After the oil pressure indicated value of the second clutch C2 is held for a predetermined time, the oil pressure indicated value is swept down toward zero (see time point t3 − time point t4). At the same time, the oil pressure indicated value of the first clutch C1 is swept up, and then the maximum value for maintaining the first clutch C1 in the fully engaged state is set. The time point t4 indicates the time point when the power-on-downshift is completed.

As described above, according to the present embodiment, at the time of power-on-downshift when the wrap-down control is executed, the second clutch is based on the gear ratio γcvt of the continuously variable transmission mechanism 24 at the start of the power-on-downshift. Since the engagement pressure of C2 is corrected with respect to the basic engagement pressure of the second clutch C2 when the wrap-down control is not executed, the torque input to the second clutch C2 via the continuously variable transmission mechanism 24 is applied. Even if the gear ratio on the lowest side is different from that of γmax, the second clutch C2 may start to slide at the target timing. In addition, when the input shaft rotation speed Nin approaches the synchronous rotation speed after the end of the power-on downshift and the inclination of the input shaft rotation speed Nin is large, the engagement of the second clutch C2 is larger than when the inclination is small. Since the pressure is increased, even if the progress of the power-on-downshift is affected by the downshift of the stepless speed change mechanism 24, the change in the input shaft rotation speed Nin can be stabilized, that is, stable power-on-downshift is performed. be able to. Therefore, the power-on-downshift when executing the wrap-down control can be appropriately advanced.

Although the examples of the present invention have been described in detail with reference to the drawings, the present invention also applies to other aspects.

For example, in the above-described embodiment, in the power-on-downshift control for lap-down, the engagement pressure of the second clutch C2 corresponds to the inclination of the input shaft rotation speed Nin when approaching the synchronous rotation speed in the gear traveling mode. The correction was a correction for increasing the engagement pressure of the second clutch C2, but the correction is not limited to this embodiment. For example, the correction of the engaging pressure of the second clutch C2 according to the inclination of the input shaft rotation speed Nin may be a correction for reducing the engaging pressure of the second clutch C2. In this case, the larger the inclination of the input shaft rotation speed Nin near the synchronous rotation speed in the gear traveling mode, the smaller the amount of decrease in the engagement pressure of the second clutch C2. Even in this way, the action of retaining the change in the input shaft rotation speed Nin in the vicinity of the synchronous rotation speed in the gear traveling mode can be changed according to the inclination of the input shaft rotation speed Nin. Even with the correction for reducing the engagement pressure of the second clutch C2 described above, when the inclination of the input shaft rotation speed Nin is large when the input shaft rotation speed Nin approaches the synchronous rotation speed after the end of the power-on downshift. The engagement pressure of the second clutch C2 is higher than that when the inclination is small. Alternatively, the correction of the engagement pressure of the second clutch C2 according to the inclination of the input shaft rotation speed Nin is a correction for increasing the engagement pressure of the second clutch C2 and a correction for decreasing the engagement pressure of the second clutch C2. The correction may be a combination of and.

Further, in the above-described embodiment, the continuously variable transmission mechanism 24 is a belt-type continuously variable transmission, but the present invention is not limited to this mode. For example, the continuously variable transmission mechanism provided in the second power transmission path PT2 may be a known toroidal type continuously variable transmission.

Further, in the above-described embodiment, the gear mechanism 28 is a gear mechanism in which one gear stage having a gear ratio on the lower side than the lowest gear ratio γmax of the continuously variable transmission mechanism 24 is formed. It is not limited to the mode. For example, the gear mechanism 28 may be a gear mechanism in which a plurality of gear stages having different gear ratios are formed. That is, the gear mechanism 28 may be a stepped transmission that shifts in two or more gears. Alternatively, the gear mechanism 28 may be a gear mechanism that forms a gear ratio on the higher side than the highest gear ratio γmin of the continuously variable transmission mechanism 24 and a gear ratio on the lower side than the lowest gear ratio γmax. good.

Further, in the above-described embodiment, the traveling mode of the power transmission device 16 is switched by using a predetermined upshift line and downshift line, but the present invention is not limited to this mode. For example, the traveling mode of the power transmission device 16 may be switched by calculating the required driving force Fdem based on the vehicle speed V and the accelerator operating amount θacc and setting a gear ratio capable of satisfying the required driving force Fdem. ..

Further, in the above-described embodiment, the torque converter 20 is used as the fluid type transmission device, but the present invention is not limited to this mode. For example, instead of the torque converter 20, another fluid type transmission device such as a fluid coupling having no torque amplification action may be used. Alternatively, this fluid transmission device does not necessarily have to be provided. Further, although the meshing clutch D1 is provided in the first power transmission path PT1 via the gear mechanism 28, the meshing clutch D1 does not necessarily have to be provided in carrying out the present invention.

It should be noted that the above is only one embodiment, and the present invention can be implemented in a mode in which various changes and improvements are made based on the knowledge of those skilled in the art.

12: Engine (power source)
14: Drive wheel 16: Vehicle power transmission device 22: Input shaft (input rotating member)
24: Continuously variable transmission mechanism 28: Gear mechanism 30: Output shaft (output rotating member)
90: Electronic control device (control device)
94: Shift control unit C1: 1st clutch (1st engaging device)
C2: 2nd clutch (2nd engaging device)
PT1: 1st power transmission path PT2: 2nd power transmission path

Claims (1)

To transmit the power from the input rotating member to the output rotating member, which is provided in parallel between the input rotating member to which the power of the power source is transmitted and the output rotating member that outputs the power to the drive wheels. The plurality of power transmission paths are provided with a first power transmission path via a gear mechanism having a gear stage, and a gear ratio on the higher side than the first power transmission path is formed in the plurality of power transmission paths. It has a second power transmission path via a stepless speed change mechanism, and the first power transmission path is formed by engagement of a first engagement device provided in the first power transmission path. The second power transmission path controls a vehicle power transmission device formed by engagement of a second engagement device provided on the drive wheel side of the stepless speed change mechanism in the second power transmission path. It ’s a device,
The state in which the second power transmission path is formed is switched to the state in which the first power transmission path is formed by the stepped speed change control by the release of the second engagement device and the engagement of the first engagement device. If the gear ratio of the continuously variable transmission mechanism is not the lowest gear ratio at the time of power-on downshift in which the downshift of the vehicle power transmission device is executed as the drive request amount increases, the continuously variable transmission mechanism It includes a shift control unit that executes lap-down control in which downshifts of the continuously variable transmission mechanism having the gear ratio as the lowest gear ratio are repeated.
At the time of the power-on-downshift when the lap-down control is executed, the shift control unit advances the power-on-downshift based on the gear ratio of the continuously variable transmission mechanism at the start of the power-on-downshift. The engagement pressure of the second engaging device, which is lowered so as to be caused, is corrected with respect to the basic engaging pressure of the second engaging device when the wrap-down control is not executed, and the input rotating member is corrected. When the rotation speed of the input rotating member approaches the synchronous rotation speed after the end of the power-on-downshift and the inclination of the rotation speed of the input rotating member is large, the engagement of the second engaging device is higher than when the inclination is small. A control device for a power transmission device for a vehicle, which is characterized by increasing the pressure.

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