JP6556597B2 - Control device for power split type continuously variable transmission - Google Patents

Description

  The present invention relates to a control device for a power split type continuously variable transmission capable of dividing power input to an input shaft (input shaft) into two systems and transmitting the power to an output shaft (output shaft).

  As a transmission mounted on a vehicle such as an automobile, a continuously variable transmission mechanism that continuously changes engine power, a gear mechanism that transmits engine power without going through a continuously variable transmission mechanism, and a continuously variable transmission mechanism There has been proposed a planetary gear mechanism for synthesizing the power from the gear and the power from the gear mechanism. In this transmission, the power from the engine can be divided into a continuously variable transmission mechanism and a gear mechanism, and the divided powers can be combined by the planetary gear mechanism and transmitted to the wheels.

JP 2004-176890 A

  The applicant has also proposed a transmission capable of dividing and transmitting the power of the drive source into two systems as a power split type continuously variable transmission.

  The power split type continuously variable transmission according to this proposal includes a continuously variable transmission mechanism, a parallel shaft gear mechanism, and a planetary gear mechanism. The continuously variable transmission mechanism has the same configuration as a known belt-type continuously variable transmission (CVT). Engine power input to the input shaft is transmitted to the primary shaft of the continuously variable transmission mechanism. The secondary shaft of the continuously variable transmission mechanism is connected to the sun gear of the planetary gear mechanism. The parallel shaft gear mechanism includes a split drive gear that transmits / cuts off the power of the input shaft, and a split driven gear that forms a gear train with the split drive gear and rotates integrally with the carrier of the planetary gear mechanism. An output shaft is connected to the ring gear of the planetary gear mechanism. The rotation of the output shaft is transmitted to the differential gear, and is transmitted from the differential gear to the left and right drive wheels.

  The power split type continuously variable transmission has a belt mode and a split mode as power transmission modes in the D range (forward range).

  In the belt mode, the sun gear and the ring gear of the planetary gear mechanism are directly connected. Further, the transmission of power from the input shaft to the split drive gear is interrupted, so that the split drive gear is in a free rotation state (free), and the carrier of the planetary gear mechanism is in a free rotation state. Therefore, the sun gear and the ring gear rotate integrally with the power output from the continuously variable transmission mechanism, and the output shaft rotates integrally with the ring gear. Therefore, in the belt mode, the gear ratio (unit gear ratio) of the power split continuously variable transmission matches the gear ratio (belt gear ratio) of the continuously variable transmission mechanism.

  In the split mode, the direct connection between the sun gear and the ring gear of the planetary gear mechanism is released. Therefore, the sun gear is rotated by the power output from the continuously variable transmission mechanism. On the other hand, power is transmitted from the input shaft to the split drive gear, and the power is shifted from the split drive gear via the split driven gear at a constant split gear ratio and input to the carrier of the planetary gear mechanism. Therefore, in the split mode, the larger the belt speed ratio, the smaller the unit speed ratio, and a speed ratio that is less than or equal to the split speed ratio can be realized.

  Further, in the R range (reverse range), the direct connection between the sun gear and the ring gear of the planetary gear mechanism is released. Further, the carrier of the planetary gear mechanism is braked and stopped. Therefore, when the sun gear is rotated by the power output from the continuously variable transmission mechanism, the output shaft rotates in the direction opposite to the rotation direction of the sun gear integrally with the ring gear. At this time, due to the configuration of the planetary gear mechanism, the rotational speed of the ring gear is necessarily lower than the rotational speed of the sun gear.

  Therefore, when compared with the same belt speed ratio, the unit speed ratio in the R range is larger than the unit speed ratio in the D range. Therefore, in the configuration in which the gear ratio of the differential gear is set based on the D range, when the belt speed ratio is set to the maximum speed ratio in the R range, the reverse driving force transmitted to each drive wheel is excessive. Thus, problems such as insufficient braking force occur.

  As a countermeasure, when the shift lever is shifted from the D position (position corresponding to the D range) to the R position (position corresponding to the R range), the belt gear ratio is changed from the maximum gear ratio to a smaller gear ratio. It is possible to change to

  Since the shift lever switches from the D range to the R range in response to the shift operation from the D position to the R position, the engaging element for directly connecting / separating the sun gear and the ring gear of the planetary gear mechanism is released, and the planetary gear mechanism carrier is released. Engagement elements that inhibit / allow rotation of the are engaged. The transition time when the engagement elements are switched, that is, the time from when the engagement element on the release side starts to be released (release point) to the time when the engagement element on the engagement side engages (engagement point) is Each engagement element slips due to the half-clutch state, and each pulley of the continuously variable transmission mechanism rotates. Since the belt speed ratio cannot be changed when each pulley of the continuously variable transmission mechanism is stopped, the belt speed ratio can be changed by using the rotation of each pulley during the transition time.

  However, if the transition time is short, a situation occurs in which the belt gear ratio does not reach the target gear ratio. On the other hand, if the transition time is long, the time lag from the D → R operation until the R range is configured increases, and the responsiveness of switching from the D range to the R range for the D → R operation decreases.

  An object of the present invention is to provide a power split type in which the transition time when switching between the first engagement element and the second engagement element can be set to a time that is sufficient to change the belt speed ratio to the target speed ratio. A control device for a continuously variable transmission is provided.

  In order to achieve the above object, a control device for a power split continuously variable transmission according to the present invention includes an input shaft to which power is input, an output shaft that outputs power, and power that is input to the input shaft. A belt-type continuously variable transmission mechanism that changes continuously by changing the belt transmission ratio, a split transmission mechanism that changes the power input to the input shaft at a constant split transmission ratio, and power from the continuously variable transmission mechanism. Output sun gear, a planetary gear mechanism for output comprising a ring gear provided to rotate integrally with an output shaft and a carrier to which power from a split transmission mechanism is input, and the sun gear and the ring gear are directly connected to each other. A first engagement element that is released in the reverse range and separates the sun gear and the ring gear, and engaged in the reverse range and prohibits rotation of the carrier, A control device for controlling a power split type continuously variable transmission including a second engagement element that is released in a range and allows rotation of a carrier, wherein the first engagement is performed according to a shift instruction for switching between a forward range and a reverse range. Control for releasing one of the engagement element or the second engagement element is started, and control for engaging the other of the first engagement element or the second engagement element is started when the delay time has elapsed from the start of the control. During the control by the switching control means and the switching control means, the belt gear ratio is changed to the target gear ratio at the beginning of a transition time in which both the first engagement element and the second engagement element are not engaged. The shift control means for starting the shift control and the excess / deficiency amount of the transient time with respect to the shift control time required for the shift control are acquired, and the transient time matches the shift control time based on the acquired excess / deficiency amount. And a learning means for learning the delay time so.

  According to this configuration, when the control for releasing one of the first engagement element or the second engagement element is started in accordance with a shift instruction for switching between the forward range and the reverse range, a delay time has elapsed from the start of the control. Then, control for engaging the other of the first engagement element and the second engagement element is started. During the control, when a transition state is entered in which both the first engagement element and the second engagement element are not engaged, the shift control for changing the belt speed ratio to the target speed ratio starts at the beginning of the transition state. Is done. Then, an excess / deficiency amount of time (transition time) from the start to the end of the transient state with respect to the shift control time required for the shift control is acquired, and based on the excess / deficiency amount, the transient time matches the shift control time. Delay time is learned.

  As a result of learning, since the transition time approaches the speed change control time, the belt speed ratio can be set to a time that is not excessive or insufficient for changing to the target speed ratio. Therefore, while suppressing the decrease in responsiveness of switching between the forward range and the reverse range due to a long transition time, the driving force suitable for the forward range or the reverse range is output from the output shaft after the switching. Can do.

  The shift instruction is an instruction for shifting from the forward range to the reverse range or an instruction for shifting from the reverse range to the forward range. For example, in a vehicle provided with a shift lever, when the shift lever is operated from the D position to the R position, a shift from the forward range to the reverse range is instructed, and the shift lever is operated from the R position to the D position. Thus, a shift from the reverse range to the forward range is instructed.

  The control device according to the present invention may be used as a control device for a belt-type continuously variable transmission. In this case, the control device includes an input shaft to which power is input, an output shaft that outputs power, and a belt-type continuously variable transmission that continuously shifts the power input to the input shaft by changing the belt speed ratio. An output planetary gear mechanism including a mechanism, a carrier, a sun gear to which power from the continuously variable transmission mechanism is input, and a ring gear provided so as to be integrally rotatable with the output shaft; and a sun gear and a ring gear engaged in a forward range. And a first engagement element that is released in the reverse range and separates the sun gear and the ring gear, and engaged in the reverse range to prohibit the rotation of the carrier and released in the forward range to allow the carrier to rotate. A control device for controlling a belt-type continuously variable transmission including a second engagement element, the first engagement according to a shift instruction for switching between a forward range and a reverse range. Control for releasing one of the elements or the second engagement element is started, and control for engaging the other of the first engagement element or the second engagement element is started when a delay time has elapsed from the start of the control. During the control by the switching control means and the switching control means, the belt speed ratio is changed to the target speed ratio at the beginning of a transition time in which both the first engagement element and the second engagement element are not engaged. The shift control means for starting the shift control and the excess / deficiency amount of the transient time with respect to the shift control time required for the shift control are acquired, and based on the acquired excess / deficiency amount, the delay time is delayed so as to coincide with the shift control time. And learning means for learning time.

  According to the present invention, it is possible to set a time when there is no excess or deficiency in changing the belt speed ratio to the target speed ratio. As a result, while suppressing a decrease in responsiveness of switching between the forward range and the reverse range due to a long transition time, a driving force suitable for the forward range or the reverse range is output from the output shaft after the switching. be able to.

It is a figure which shows the structure of the principal part of the vehicle by which the control apparatus which concerns on one Embodiment of this invention is mounted. It is a skeleton figure which shows the structure of the drive system of a vehicle. It is a figure which shows the state of the belt mode clutch, reverse brake, and split mode brake at the time of forward movement and reverse travel of the vehicle. It is a collinear diagram which shows the relationship of the rotation speed (rotation speed) of the sun gear of a planetary gear mechanism for an output, a carrier, and a ring gear. It is a figure which shows an example of the time change of the shift position at the time of switching from D range to R range, a belt gear ratio, a turbine speed, and a hydraulic pressure. It is a figure which shows the other example of the time change of the shift position at the time of switching from D range to R range, a belt gear ratio, a turbine speed, and a hydraulic pressure.

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

<Vehicle configuration>
FIG. 1 is a diagram illustrating a configuration of a main part of a vehicle 1 on which a control device according to an embodiment of the present invention is mounted.

  The vehicle 1 is an automobile that uses the engine 2 as a drive source.

  The engine 2 is provided with an electronic throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 2, an injector (fuel injection device) that injects fuel into the intake air, and an ignition plug that generates electric discharge in the combustion chamber. It has been. The engine 2 is also provided with a starter for starting the engine 2. The output of the engine 2 is transmitted to driving wheels (for example, left and right front wheels) of the vehicle 1 via a torque converter 3 and a power split type continuously variable transmission (CVT) 4.

  The vehicle 1 includes a plurality of ECUs (Electronic Control Units) having a configuration including a CPU, a ROM, a RAM, and the like. The plurality of ECUs include a transmission ECU 11. Each ECU is connected so that bidirectional communication by a CAN (Controller Area Network) communication protocol is possible.

  A shift position sensor 12 and a turbine speed sensor 13 are connected to the transmission ECU 11.

  The shift position sensor 12 outputs a detection signal corresponding to the position of the shift lever (select lever). As positions of the shift lever, for example, a P position, an R position, an N position, and a D position are provided. The P position, the R position, the N position, and the D position correspond to the P range (parking range), R range (reverse range), N range (neutral range), and D range (forward range), respectively. The shift lever can be shifted between the P position, the R position, the N position, and the D position, and the shift range can be instructed by the shift operation.

  The turbine speed sensor 13 outputs a pulse signal synchronized with the rotation of the turbine runner 32 (see FIG. 2) of the torque converter 3 as a detection signal. The transmission ECU 11 converts the frequency of the pulse signal input from the turbine rotation speed sensor 13 into a turbine rotation speed that is the rotation speed of the turbine runner 32.

  Based on information acquired from detection signals of various sensors and / or various information input from other ECUs, the transmission ECU 11 is configured to change the power ratio of the power split continuously variable transmission 4, for example. Various valves provided in a hydraulic circuit 14 for supplying hydraulic pressure to each part of the split type continuously variable transmission 4 are controlled. The valves include a C1 valve 15 and a B1 valve 16 for controlling the hydraulic pressure supplied to the belt mode clutch C1 and the reverse brake B1 (described later), respectively. As the C1 valve 15 and the B1 valve 16, a valve capable of controlling the output hydraulic pressure by a current value, for example, a linear solenoid valve is used. Further, the hydraulic circuit 14 is provided with a mechanical oil pump driven by the power of the engine 2 as a generation source of hydraulic pressure.

<Configuration of drive system>
FIG. 2 is a skeleton diagram showing the configuration of the drive system of the vehicle 1.

  The torque converter 3 includes a pump impeller 31, a turbine runner 32, and a lockup clutch 33. An output shaft (E / G output shaft) of the engine 2 is connected to the pump impeller 31, and the pump impeller 31 is provided so as to be integrally rotatable around the same rotation axis as the E / G output shaft. ing. The turbine runner 32 is provided to be rotatable about the same rotation axis as the pump impeller 31. The lockup clutch 33 is provided to directly connect / separate the pump impeller 31 and the turbine runner 32. When the lockup clutch 33 is engaged, the pump impeller 31 and the turbine runner 32 are directly connected, and when the lockup clutch 33 is released, the pump impeller 31 and the turbine runner 32 are separated.

  When the E / G output shaft is rotated in a state where the lockup clutch 33 is released, the pump impeller 31 rotates. When the pump impeller 31 rotates, an oil flow from the pump impeller 31 toward the turbine runner 32 is generated. This oil flow is received by the turbine runner 32 and the turbine runner 32 rotates. At this time, the amplifying action of the torque converter 3 occurs, and the turbine runner 32 generates a power larger than the power (torque) of the E / G output shaft.

  When the lockup clutch 33 is engaged, when the E / G output shaft is rotated, the E / G output shaft, the pump impeller 31 and the turbine runner 32 are rotated together.

  The power split type continuously variable transmission 4 includes an input shaft 41, an output shaft 42, a continuously variable transmission mechanism 43, an output planetary gear mechanism 44, and a split transmission mechanism 45.

  The input shaft 41 is connected to the turbine runner 32 of the torque converter 3 and is provided so as to be integrally rotatable about the same rotation axis as the turbine runner 32.

  The output shaft 42 is provided in parallel with the input shaft 41. An output gear 46 is supported on the output shaft 42 so as not to be relatively rotatable.

  The continuously variable transmission mechanism 43 has the same configuration as a known belt-type continuously variable transmission (CVT). Specifically, the continuously variable transmission mechanism 43 includes a primary shaft 51, a secondary shaft 52 provided in parallel with the primary shaft 51, a primary pulley 53 supported by the primary shaft 51 so as not to be relatively rotatable, and a secondary shaft 52. And a secondary pulley 54 supported so as not to rotate relative thereto, and a primary pulley 53 and a belt 55 wound around the secondary pulley 54.

  The primary pulley 53 is disposed so as to face the fixed sheave 61 fixed to the primary shaft 51 with the belt 55 sandwiched between the fixed sheave 61 and is supported by the primary shaft 51 so as to be movable in the axial direction but not to be relatively rotatable. 62. A cylinder 63 fixed to the primary shaft 51 is provided on the opposite side of the movable sheave 62 from the fixed sheave 61, and a piston chamber (oil chamber) 64 is formed between the movable sheave 62 and the cylinder 63. Yes.

  The secondary pulley 54 is arranged so as to be opposed to the fixed sheave 65 fixed to the secondary shaft 52 with the belt 55 sandwiched between the fixed sheave 65 and supported on the secondary shaft 52 so as to be movable in the axial direction but not to be relatively rotatable. 66. A cylinder 67 fixed to the secondary shaft 52 is provided on the opposite side of the movable sheave 66 from the fixed sheave 65, and a piston chamber (oil chamber) 68 is formed between the movable sheave 66 and the cylinder 67. Yes.

  In the continuously variable transmission mechanism 43, the oil pressure supplied to the piston chambers 64 and 68 of the primary pulley 53 and the secondary pulley 54 is controlled, and the groove widths of the primary pulley 53 and the secondary pulley 54 are changed. The belt transmission ratio, which is the transmission ratio in the step transmission mechanism 43, is continuously changed steplessly.

  Specifically, when the belt speed ratio is lowered, the hydraulic pressure supplied to the piston chamber 64 of the primary pulley 53 is increased. As a result, the movable sheave 62 of the primary pulley 53 moves to the fixed sheave 61 side, and the interval (groove width) between the fixed sheave 61 and the movable sheave 62 is reduced. Accordingly, the winding diameter of the belt 55 around the primary pulley 53 is increased, and the interval (groove width) between the fixed sheave 65 and the movable sheave 66 of the secondary pulley 54 is increased. As a result, the pulley ratio between the primary pulley 53 and the secondary pulley 54 is reduced, and the belt transmission ratio is reduced.

  When the belt transmission ratio is increased, the hydraulic pressure supplied to the piston chamber 64 of the primary pulley 53 is decreased. Thereby, the thrust of the secondary pulley 54 with respect to the belt 55 becomes larger than the thrust of the primary pulley 53 with respect to the belt 55, the interval between the fixed sheave 65 and the movable sheave 66 of the secondary pulley 54 is reduced, and the fixed sheave 61 and the movable sheave The distance from 62 increases. As a result, the pulley ratio between the primary pulley 53 and the secondary pulley 54 is increased, and the belt transmission ratio is increased.

  On the other hand, the thrust of the primary pulley 53 and the secondary pulley 54 needs to be large enough to prevent slippage between the primary pulley 53 and the secondary pulley 54 and the belt 55. Therefore, the hydraulic pressure (oil amount) supplied to the piston chambers 64 and 68 of the primary pulley 53 and the secondary pulley 54 is controlled so that a thrust according to the magnitude of the torque input to the primary shaft 51 is obtained.

  The output planetary gear mechanism 44 includes a sun gear 71, a carrier 72, and a ring gear 73. The sun gear 71 is supported by the secondary shaft 52 so as not to rotate relative to the sun gear 71 (provided so as to be integrally rotatable about the same rotational axis as the secondary shaft 52). The carrier 72 is fitted on the output shaft 42 so as to be relatively rotatable. The carrier 72 supports a plurality of pinion gears 74 in a rotatable manner. The plurality of pinion gears 74 are arranged on the circumference and mesh with the sun gear 71. The ring gear 73 has an annular shape that collectively surrounds the plurality of pinion gears 74, and meshes with each pinion gear 74 from the outer side in the rotational radial direction of the secondary shaft 52. An output shaft 42 is connected to the ring gear 73, and the ring gear 73 is provided so as to be integrally rotatable about the same rotation axis as the output shaft 42.

  The split transmission mechanism 45 includes a speed increasing planetary gear mechanism 81, a split drive gear 82, a split driven gear 83, and an idle gear 84.

  The speed increasing planetary gear mechanism 81 includes a sun gear 85, a carrier 86, and a ring gear 87. The sun gear 85 is fitted on the input shaft 41 so as to be relatively rotatable. The carrier 86 is supported by the input shaft 41 so as not to rotate relative to the input shaft 41. The carrier 86 rotatably supports a plurality of pinion gears 88. The plurality of pinion gears 88 are arranged on the circumference and mesh with the sun gear 85. The ring gear 87 has an annular shape that collectively surrounds the plurality of pinion gears 88, and meshes with each pinion gear 88 from the outside in the rotational radial direction of the input shaft 41.

  The split drive gear 82 is provided so as to be integrally rotatable with the sun gear 85 of the speed increasing planetary gear mechanism 81.

  The split driven gear 83 is provided so as to rotate integrally with the carrier 72 of the output planetary gear mechanism 44.

  The idle gear 84 meshes with the split drive gear 82 and the split driven gear 83.

  The power split type continuously variable transmission 4 includes an output gear mechanism 91 that transmits the rotation of the output gear 46 to the differential gear 5. The output gear mechanism 91 includes an output idle shaft 92 provided in parallel with the output shaft 42, a first output idle gear 93 that is supported by the output idle shaft 92 so as not to rotate relative to the output gear 46, and an output A second output idle gear 94 that is supported by the idle shaft 92 so as not to be relatively rotatable and meshes with the differential gear 5 (the input gear of the differential gear 5) is included.

  The power split type continuously variable transmission 4 includes a belt mode clutch C1, a reverse brake B1, and a split mode brake B2.

  The belt mode clutch C1 is switched between an engaged state (on) in which the output shaft 42 and the secondary shaft 52 are directly connected (connected so as to be integrally rotatable) and a released state (off) in which the direct connection is released.

  The reverse brake B <b> 1 is switched between an engagement state (ON) for braking the split drive gear 82 (the carrier 72 of the output planetary gear mechanism 44) and a release state (OFF) allowing the rotation of the split drive gear 82.

  The split mode brake B2 is switched between an engaged state (on) for braking the ring gear 87 of the speed increasing planetary gear mechanism 81 and a released state (off) allowing the rotation of the ring gear 87.

<Power transmission mode>
FIG. 3 is a diagram illustrating states of the belt mode clutch C1, the reverse brake B1, and the split mode brake B2 when the vehicle 1 moves forward and backward. FIG. 4 is a collinear diagram showing the relationship among the rotational speeds (rotational speeds) of the sun gear 71, the carrier 72, and the ring gear 73 of the output planetary gear mechanism 44.

  In FIG. 3, “◯” indicates that the belt mode clutch C1, the reverse brake B1, and the split mode brake B2 are engaged. “X” indicates that the belt mode clutch C1, the reverse brake B1, and the split mode brake B2 are in a released state.

  The power split type continuously variable transmission 4 has a belt mode and a split mode as power transmission modes in the D range.

  In the belt mode, as shown in FIG. 3, the belt mode clutch C1 is engaged. Thereby, the output shaft 42 and the secondary shaft 52 are directly connected. Further, the reverse brake B1 and the split mode brake B2 are released. In a state where the reverse brake B1 is released, the split drive gear 82, the split driven gear 83 and the idle gear 84 of the split transmission mechanism 45, and the carrier 72 of the output planetary gear mechanism 44 are free (in a freely rotating state). In the state in which the split mode brake B2 is released, the ring gear 87 of the speed increasing planetary gear mechanism 81 of the split transmission mechanism 45 is free.

  The power input to the input shaft 41 is transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43 to rotate the primary shaft 51 and the primary pulley 53. The rotation of the primary pulley 53 is transmitted to the secondary pulley 54 via the belt 55 to rotate the secondary pulley 54 and the secondary shaft 52. Since the output shaft 42 and the secondary shaft 52 are directly connected, the output shaft 42 rotates together with the secondary shaft 52. Therefore, in the belt mode, as shown in FIG. 4, the unit speed ratio, which is the overall speed ratio of the power split type continuously variable transmission 4, matches the belt speed ratio.

  In the split mode, as shown in FIG. 3, the split mode brake B2 is engaged. As a result, the ring gear 87 of the speed increasing planetary gear mechanism 81 of the split transmission mechanism 45 is braked. Further, the belt mode clutch C1 and the reverse brake B1 are released. In a state where the belt mode clutch C1 is released, the direct connection between the output shaft 42 and the secondary shaft 52 is released.

  A part of the power input to the input shaft 41 is transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43 to rotate the primary shaft 51 and the primary pulley 53. The rotation of the primary pulley 53 is transmitted to the secondary pulley 54 via the belt 55 to rotate the secondary pulley 54 and the secondary shaft 52. The sun gear 71 of the output planetary gear mechanism 44 is rotated by the rotation of the secondary shaft 52.

  Further, since the ring gear 87 of the split transmission mechanism 45 is braked, part of the power input to the input shaft 41 causes the carrier 86 of the split transmission mechanism 45 to revolve and the pinion gear held by the carrier 86. Rotate 88. As the pinion gear 88 rotates, power is input from the pinion gear 88 to the sun gear 85. As a result, the split drive gear 82 rotates. The rotation of the split drive gear 82 is transmitted to the split driven gear 83 via the idle gear 84 and rotates the carrier 72 of the split driven gear 83 and the output planetary gear mechanism 44.

  Since the split transmission ratio, which is the transmission ratio of the split transmission mechanism 45, is constant and unchanged (fixed), in the split mode, if the power input to the input shaft 41 is constant, the carrier of the output planetary gear mechanism 44 The rotation of 72 is maintained at a constant speed. Therefore, when the belt speed ratio is increased, the rotational speed of the sun gear 71 of the output planetary gear mechanism 44 decreases, so that the ring gear 73 (output shaft 42) of the output planetary gear mechanism 44 is shown by a broken line in FIG. ) Will increase. As a result, in the split mode, the unit transmission ratio decreases as the belt transmission ratio increases.

  The rotation of the output shaft 42 in the belt mode and the split mode is transmitted to the differential gear 5 via the output gear 46 and the output gear mechanism 91. Thereby, the drive shafts 6 and 7 of the vehicle 1 rotate in the forward direction.

  In the R range, as shown in FIG. 3, the belt mode clutch C1 and the split mode brake B2 are released. Then, the reverse brake B1 is engaged. As a result, the split drive gear 82 is braked. Due to the braking of the split drive gear 82, the idle gear 84 of the split transmission mechanism 45 cannot be rotated, and further, the split driven gear 83 of the split transmission mechanism 45 and the carrier 72 of the output planetary gear mechanism 44 cannot be rotated.

  The power input to the input shaft 41 is transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43 to rotate the primary shaft 51 and the primary pulley 53. The rotation of the primary pulley 53 is transmitted to the secondary pulley 54 via the belt 55 to rotate the secondary pulley 54 and the secondary shaft 52. The sun gear 71 of the output planetary gear mechanism 44 is rotated by the rotation of the secondary shaft 52. Since the carrier 72 cannot rotate, when the sun gear 71 rotates as shown by a two-dot chain line in FIG. 4, the ring gear 73 rotates in the opposite direction to the sun gear 71. The rotation direction of the ring gear 73 is opposite to the rotation direction of the ring gear 73 in the D range (belt mode and split mode). Then, the output shaft 42 rotates integrally with the ring gear 73. The rotation of the output shaft 42 is transmitted to the differential gear 5 via the output gear 46 and the output gear mechanism 91. As a result, the drive shafts 6 and 7 of the vehicle 1 rotate in the reverse direction.

<D → R shift control>
FIG. 5A and FIG. 5B are diagrams illustrating an example of a change over time of the shift position, the belt speed ratio, the turbine speed, and the hydraulic pressure when switching from the D range to the R range.

  When the shift lever is operated from the D position to the R position (time T1), the transmission ECU 11 determines that an instruction (shift instruction) for switching from the D range to the R range by operating the shift lever is input. Then, in accordance with the shift instruction, D → R shift control is executed by the transmission ECU 11.

  The D → R shift control includes a switching control for switching the belt mode clutch C1 and the reverse brake B1, and a shift control for reducing the belt speed ratio to the target speed ratio. Further, the switching control includes release control for releasing the engaged belt mode clutch C1 and engagement control for engaging the released reverse brake B1.

  When the shift instruction is input, the release control is started by the transmission ECU 11 (time T1). In the release control, the current supplied to the C1 valve 15 (see FIG. 1) for the belt mode clutch C1 is controlled, and the C1 pressure, which is the hydraulic pressure supplied to the belt mode clutch C1, is maximized (the C1 valve 15 is fully opened). After the pressure is reduced to a predetermined release pressure, the C1 pressure gradually changes from the release pressure over a predetermined time (gradually decreases with time). Thereafter, the C1 pressure is reduced to 0, and the release control is terminated.

  When a predetermined delay time ΔT (time T1-T2) has elapsed from the input of the shift instruction, the transmission ECU 11 starts engagement control (time T2). In the engagement control, the current supplied to the B1 valve 16 (see FIG. 1) for the reverse brake B1 is controlled, and the B1 pressure, which is the hydraulic pressure supplied to the reverse brake B1, is increased to a predetermined initial engagement pressure. After that, the B1 pressure is gradually increased from the initial engagement pressure by a sweep with a constant time gradient (time change rate).

  When the C1 pressure is reduced to the release pressure, the belt mode clutch C1 slips, and the primary shaft 51, the secondary shaft 52, the primary pulley 53, the secondary pulley 54, and the belt 55 shown in FIG. A rising blowing state occurs (time T3). On the other hand, the reverse brake B1 starts to engage while sliding by the sweep of the B1 pressure. When the reverse brake B1 is engaged in a state where no slip occurs, the rotation of the primary shaft 51, the secondary shaft 52, the primary pulley 53, the secondary pulley 54, and the belt 55 is stopped, and the blowing state of the turbine speed is eliminated. (Time T4).

  When the blowing state of the turbine speed is eliminated, the B1 pressure is increased to the maximum pressure (the fully open pressure of the B1 valve 16), and the engagement control is ended.

  On the other hand, when the blowing state of the turbine speed occurs, the transmission ECU 11 starts the shift control. In the shift control, the primary sheave pressure, which is the hydraulic pressure supplied to the piston chamber 64 (see FIG. 2) of the primary pulley 53 of the continuously variable transmission mechanism 43, is constant so that the belt transmission ratio is reduced to a constant target transmission ratio. Raised with a time gradient.

<Learning time learning>
When the belt mode clutch C1 starts to slip, a transitional state is reached in which both the belt mode clutch C1 and the reverse brake B1 are not engaged. In the transient state, the primary shaft 51, the secondary shaft 52, the primary pulley 53, the secondary pulley 54, and the belt 55 rotate, so that the belt gear ratio can be changed. The transient state ends when the reverse brake B1 is engaged in a non-slip state. The time during which the transient state continues (transition time) depends on the oil discharge amount of the mechanical oil pump provided in the hydraulic circuit 14 (see FIG. 1), the end play of the reverse brake B1 (piston stroke amount), and the like. Depending on individual differences and deterioration over time.

  As shown in FIG. 5A, when the transition time (time T3-T4) is shorter than the time required to reduce the belt speed ratio to the target speed ratio, that is, the speed control time required for speed control (time T3-T5). In this case, the transition time ends in the middle of the speed change control, and the belt speed ratio does not reach the target speed ratio.

  In this case, based on the measured value of the transition time (time T3-T4) and the calculated value of the belt speed ratio decreasing speed (corresponding to the slope θ of the straight line indicating the time change of the belt speed ratio) by the transmission ECU 11. An insufficient amount (time T4-T5) of the transition time (time T3-T4) with respect to the shift control time (time T3-T5) is acquired. Then, the delay time ΔT from the input of the shift instruction to the start of the engagement control is corrected to be increased by an insufficient amount (time T4-T5). The increased delay time ΔT is used for the next switching control.

  The belt speed ratio can be obtained by dividing the rotational speed of the primary pulley 53 by the rotational speed of the secondary pulley 54, and the belt speed ratio decreasing speed can be obtained by time differentiation of the belt speed ratio. it can.

  On the other hand, as shown in FIG. 5B, when the transient time (time T3-T4) is longer than the shift control time (time T3-T5), the transmission ECU 11 measures the transient time (time T3-T4). The actual value of the shift control time (time T3-T5) is subtracted from the value to obtain an excessive amount (time T5-T4) of the transient time (time T3-T4). Then, the delay time ΔT from the input of the shift instruction to the start of the engagement control is corrected to decrease by an excessive amount (time T5-T4). The decreased delay time ΔT is used for the next change control.

  In this way, the delay time ΔT is learned so that the transient time (time T3-T4) matches the shift control time (time T3-T5).

<Effect>
As described above, the release control for releasing the belt mode clutch C1 is started in accordance with the switching instruction from the D range to the R range, and when the delay time ΔT has elapsed from the start of the release control, the reverse brake B1 is engaged. Control to be combined is started. If a transition state in which both the belt mode clutch C1 and the reverse brake B1 are not engaged during the control is entered, the shift control for changing the belt speed ratio to the target speed ratio is started at the beginning of the transition state. Then, an excess / deficiency amount of time (transition time) from the start to the end of the transient state with respect to the shift control time required for the shift control is acquired, and based on the excess / deficiency amount, the transient time matches the shift control time. The delay time ΔT is learned.

  As a result of learning, since the transition time approaches the speed change control time, the belt speed ratio can be set to a time that is not excessive or insufficient for changing to the target speed ratio. Therefore, while suppressing a decrease in responsiveness of switching between the D range and the R range due to a long transition time, a driving force suitable for the D range or the R range is output from the output shaft 42 after the switching. be able to.

<Modification>
As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form.

  For example, in the above-described embodiment, the D → R shift control executed according to the switching instruction from the D range to the R range has been described. However, the R → D shift control executed according to the switching from the R range to the D range is described. The present invention may be applied.

  That is, in the R → D shift control, release control for releasing the reverse brake B1 is started in accordance with an instruction to switch from the R range to the D range, and when the delay time has elapsed from the start of the release control, the belt mode clutch Control for engaging C1 is started. If a transition state in which both the belt mode clutch C1 and the reverse brake B1 are not engaged during the control is entered, the target transmission ratio is greater than the belt transmission ratio in the R range, triggered by the beginning of the transient state. Shift control to be changed to is started. When the present invention is applied to R → D control, an excess / deficiency amount of the transient time with respect to the shift control time required for the shift control is acquired, and the transient time matches the shift control time based on the excess / deficiency amount. The delay time is learned as follows.

  In the above-described embodiment, the mechanical oil pump is provided in the hydraulic circuit 14. However, in addition to the mechanical oil pump, an electric oil pump driven by the power of the electric motor is provided in the hydraulic circuit 14. It may be done. The present invention is also applicable to control of a power split type continuously variable transmission that employs an electric oil pump.

  Each of the above-described sensors is merely an example of a sensor related to the present invention, and other sensors may be connected to the transmission ECU 11.

  In addition, various design changes can be made to the above-described configuration within the scope of the matters described in the claims.

4 power split type continuously variable transmission 11 transmission ECU (control device, change control means, speed change control means, learning means)
41 input shaft 42 output shaft 43 continuously variable transmission mechanism 44 planetary gear mechanism for output 45 split transmission mechanism 71 sun gear 72 carrier 73 ring gear B1 reverse brake (first engagement element, second engagement element)
C1 belt mode clutch (first engagement element, second engagement element)
ΔT delay time

Claims (1)

An input shaft to which power is input; an output shaft for outputting power; a belt-type continuously variable transmission mechanism that continuously changes power input to the input shaft by changing a belt speed ratio; and the input shaft A split transmission mechanism for shifting the power input to the vehicle at a constant split gear ratio, a sun gear to which power from the continuously variable transmission mechanism is input, a carrier to which power from the split transmission mechanism is input, and the output shaft And an output planetary gear mechanism provided with a ring gear provided so as to be integrally rotatable, and the sun gear and the ring gear are directly connected by being engaged in a forward range, and the sun gear and the ring gear are separated by being released in a reverse range. Engage with the first engagement element in the reverse range to inhibit rotation of the carrier and release in the forward range to A control device for controlling a power split type continuously variable transmission and a second engagement element that permits rotation of Yaria,
In accordance with a shift instruction for switching between the forward range and the reverse range, control for releasing one of the first engagement element or the second engagement element is started, and when a delay time has elapsed from the start of the control, Change control means for starting control to engage the other of the first engagement element or the second engagement element;
A shift that changes the belt speed ratio to the target speed ratio at the beginning of a transition time in which both the first engagement element and the second engagement element are not engaged during the control by the switching control means. Shift control means for starting control;
Learning to acquire an excess / deficiency amount of the transient time with respect to the shift control time required for the shift control, and learning the delay time based on the acquired excess / deficiency amount so that the transient time coincides with the shift control time And a control device.

Images