JP6505447B2 - Control device of power split type continuously variable transmission - Google Patents

Description

  The present invention relates to a control device of a power split type continuously variable transmission.

  As a transmission mounted on a vehicle such as an automobile, there is a continuously variable transmission mechanism for continuously changing the power of the engine, a gear mechanism for transmitting the power of the engine without passing through the continuously variable transmission mechanism, and a continuously variable transmission mechanism It has been proposed to have a planetary gear mechanism for combining the power from the gear and the power from the gear mechanism. In this transmission, the power from the engine can be divided into the continuously variable transmission mechanism and the gear mechanism, and each divided power can be synthesized 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 for continuously changing the power by changing the gear ratio, a constant transmission mechanism for changing the power at a constant gear ratio, and a continuously variable transmission mechanism And a planetary gear mechanism for combining the motive power passing through and the motive power passing through the fixed transmission mechanism. The continuously variable transmission mechanism has a configuration similar to that of a known belt-type continuously variable transmission (CVT). The secondary shaft of the continuously variable transmission mechanism is connected to the sun gear of the planetary gear mechanism. Further, an output shaft is connected to a ring gear of the planetary gear mechanism. The rotation of the output shaft is transmitted to the differential gear and transmitted from the differential gear to the left and right drive wheels.

  In this power split type continuously variable transmission, as a power transmission mode, a belt mode in which power is transmitted to the planetary gear mechanism only via the continuously variable transmission mechanism, power through the continuously variable transmission mechanism and constant speed transmission mechanism And a split mode to be transmitted to the planetary gear mechanism.

  In the belt mode, the sun gear and the ring gear of the planetary gear mechanism are directly connected, and the carrier of the planetary gear mechanism is made free. Therefore, the sun gear and the ring gear rotate integrally and the output shaft rotates integrally with the ring gear by the power output from the continuously variable transmission mechanism. Therefore, in the belt mode, the transmission ratio of the power split type continuously variable transmission matches the transmission ratio (belt transmission ratio) of the continuously variable transmission mechanism.

  In the split mode, the direct connection between the sun gear and the ring gear is released, and the power passing through the constant speed change mechanism is input to the carrier. Since the transmission gear ratio (split transmission gear ratio) of the constant transmission mechanism is constant and unchanged, if the rotational speed input to the power split type continuously variable transmission is constant, the rotational speed of the carrier is maintained constant. Therefore, when the belt gear ratio is increased and the rotational speed of the sun gear is decreased, the rotational speed of the ring gear and the output shaft connected to the ring gear is increased, and the gear ratio of the power split continuously variable transmission is reduced. Therefore, in the split mode, the transmission ratio of the power split type continuously variable transmission becomes equal to or less than the split transmission ratio.

  If the accelerator pedal is depressed quickly and greatly while traveling in split mode, the power transmission mode is split mode due to kickdown control, changing the belt transmission ratio by hydraulic pressure, and switching of two engagement elements by hydraulic pressure. May be switched to belt mode.

  When the engine speed is low, the flow rate of the oil discharged by the oil pump driven by the power of the engine is small. Therefore, when kickdown control with switching from the split mode to the belt mode is performed at a low engine speed, the flow rate of oil supplied to the continuously variable transmission mechanism and the engaging element is insufficient, and controllability is achieved. May deteriorate.

  An object of the present invention is to provide a control device of a power split type continuously variable transmission which can improve controllability in kick down control accompanied by switching from split mode to belt mode.

  In order to achieve the above object, a control device according to the present invention comprises a drive source, an oil pump driven by the drive source, an input shaft to which power from the drive source is input, and power input to the input shaft. Belt-type continuously variable transmission mechanism that performs stepless shifting by changing the belt transmission ratio, constant transmission mechanism that changes the power input to the input shaft at a constant split transmission ratio, output gear mechanism that outputs power to the output shaft, And an oil pump generated hydraulically engaged engagement element, and the engagement of the engagement element causes the power input to the input shaft to be transmitted to the output gear mechanism via the continuously variable transmission mechanism and the constant transmission mechanism. It is used for a vehicle equipped with a power split type continuously variable transmission in which the split mode to be transmitted is switched to the belt mode in which the power input to the input shaft is transferred to the output gear mechanism via the stepless transmission mechanism. A control device for controlling a force-splitting continuously variable transmission, comprising: determining means for determining execution of kickdown control accompanied by switching from the split mode to the belt mode together with the change of the belt transmission ratio; In response to the determination, the transmission control means starts changing the belt transmission ratio by controlling the hydraulic pressure supplied to the continuously variable transmission mechanism, the discharge flow rate calculation means calculates the flow rate of oil discharged from the oil pump, and the belt Necessary flow rate calculation means for calculating the sum of the flow rate of oil required to change the transmission ratio and the flow rate of oil required for engagement of the engagement element, and the execution of kickdown control Engaging control means for comparing the calculated flow rate with the flow rate calculated by the required flow rate calculating means and starting supply of the hydraulic pressure to the engaging element based on the comparison result

  According to this configuration, when it is determined to execute kickdown control accompanied by switching from the split mode to the belt mode, in response to the determination, the belt transmission ratio is controlled by controlling the hydraulic pressure supplied to the continuously variable transmission mechanism. The change is initiated. On the other hand, the sum of the flow rate of oil required to change the belt transmission ratio and the flow rate of oil required to engage the engagement element for switching from the split mode to the belt mode is calculated as the required flow rate. Further, the flow rate of oil discharged from the oil pump is calculated as the supply flow rate. Then, the required flow rate and the supply flow rate are compared, and based on the comparison result, the supply of the hydraulic pressure to the engagement element is started. For example, when the supply flow rate exceeds the required flow rate, the supply of hydraulic pressure to the engagement element is started.

  As a result, it is possible to suppress the occurrence of a shortage in the flow rate of oil supplied to the continuously variable transmission mechanism and the engagement element, and controllability of kickdown control accompanied by switching from split mode to belt mode together with change of belt transmission ratio. It can improve.

  According to the present invention, in kick-down control involving switching from the split mode to the belt mode together with the change of the belt transmission ratio, it is possible to suppress the occurrence of shortage of the flow rate of oil supplied to the continuously variable transmission mechanism and the engagement element , Its controllability can be improved. As a result, it is possible to suppress the variation in the response of the engagement element, and to suppress the occurrence of the shift shock.

It is a figure showing composition of an important section of vehicles by which a control device concerning one embodiment of the present invention was carried. FIG. 2 is a skeleton diagram showing a configuration of a drive system of a vehicle. FIG. 6 is a view showing states of a low clutch, a reverse brake and a high brake when the vehicle is moving forward and backward. It is a figure which shows the relationship between the gear ratio of a continuously variable transmission mechanism, and the gear ratio of a power split type continuously variable transmission. It is an alignment chart which shows the relationship of the rotation speed of the carrier of an output gear mechanism, a sun gear, and a ring gear. It is a timing chart for explaining kickdown control. It is a flowchart which shows the flow of fill timing determination processing.

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

<Main Configuration of Vehicle>

  FIG. 1 is a view showing the configuration of the main part of a vehicle 1 equipped with a control device according to an embodiment of the present invention.

  The vehicle 1 is an automobile having an engine 2 as a drive source.

  The output of the engine 2 is transmitted to drive wheels (for example, left and right front wheels) of the vehicle 1 via the torque converter 3 and the power split type continuously variable transmission 4. The engine 2 is provided with a throttle valve for adjusting the amount of intake air to the combustion chamber of the engine 2 and an ignition plug for generating an electric discharge in the combustion chamber. The engine 2 is additionally provided with a starter for starting it.

  The vehicle 1 is provided with a plurality of ECUs (electronic control units) configured to include a CPU, a ROM, a RAM, and the like. The ECU includes an engine ECU 11 and a transmission ECU 12. The plurality of ECUs are connected so as to enable two-way communication by a CAN (Controller Area Network) communication protocol.

  An accelerator sensor 13 and an engine speed sensor 14 are connected to the engine ECU 11.

  The accelerator sensor 13 inputs a signal corresponding to the amount of operation of an accelerator pedal (not shown) to the engine ECU 11. Based on the signal input from the accelerator sensor 13, the engine ECU 11 sets the ratio of the operation amount to the maximum operation amount of the accelerator pedal, that is, 0% when the accelerator pedal is not depressed, and the accelerator pedal is depressed maximally. Calculate the accelerator opening that is a percentage that makes the time 100%.

  The engine speed sensor 14 inputs a pulse signal synchronized with the rotation of the engine 2 (rotation of the crankshaft) to the engine ECU 11. The engine ECU 11 converts the frequency of the pulse signal input from the engine speed sensor 14 into the speed of the engine 2 (engine speed).

  The engine ECU 11 is a throttle provided to the engine 2 for starting, stopping, and adjusting the output of the engine 2 based on numerical values obtained from signals input from various sensors and various information input from other ECUs, etc. Control valves and spark plugs.

  A shift position sensor 15, a primary rotation number sensor 16, a secondary rotation number sensor 17, an output rotation number sensor 18, etc. are connected to the transmission ECU 12.

  The shift position sensor 15 inputs a signal corresponding to the position of the shift lever (select lever) to the transmission ECU 12. For example, a P position, an R position, an N position and a D position are provided as positions of the shift lever. The P position, R position, N position and D position respectively correspond to the P range (parking range), R range (reverse range), N range (neutral range) and D range (forward range) of the shift range. The shift lever can shift between P position, R position, N position and D position, and the shift operation can instruct switching of the shift range.

  Primary rotation speed sensor 16 inputs, for example, a pulse signal synchronized with the rotation of primary pulley 53 (see FIG. 2) of power split type continuously variable transmission 4 to transmission ECU 12. The transmission ECU 12 converts the frequency of the pulse signal input from the primary rotation speed sensor 16 into a primary rotation speed which is the rotation speed of the primary pulley 53 (primary shaft 51).

  Secondary revolution number sensor 17 inputs, for example, a pulse signal synchronized with the rotation of secondary pulley 54 (see FIG. 2) of power split type continuously variable transmission 4 to transmission ECU 12. The transmission ECU 12 converts the frequency of the pulse signal input from the secondary rotation speed sensor 17 into a secondary rotation speed which is the rotation speed of the secondary pulley 54 (secondary shaft 52).

  The output rotation speed sensor 18 inputs, for example, a pulse signal synchronized with the rotation of the output gear 85 (see FIG. 2) to the transmission ECU 12. The transmission ECU 12 converts the frequency of the pulse signal input from the output rotational speed sensor 18 into an output rotational speed which is the rotational speed of the output shaft 42 (see FIG. 2).

The transmission ECU 12 is a transmission ratio of the continuously variable transmission mechanism 43 (hereinafter referred to as "belt transmission ratio") based on numerical values obtained from signals input from various sensors and various information input from other ECUs. In order to control γ _b , a valve (not shown) included in a hydraulic circuit 19 for supplying hydraulic pressure to each part of the continuously variable transmission mechanism 43 is controlled. In addition, the transmission ECU 12 controls the hydraulic pressure supplied to the low clutch C1, the reverse brake B1 and the high brake B2 (see FIG. 2) by controlling the valves included in the hydraulic circuit 19 to set the forward mode and the reverse mode. Switch and switch between belt mode and split mode.

  The valves of the hydraulic circuit 19 include hydraulic control valves for adjusting the hydraulic pressure supplied to the primary pulley 53, secondary pulley 54, low clutch C1, reverse brake B1 and high brake B2, respectively. As the hydraulic control valve, a valve capable of controlling the output hydraulic pressure by a current value, for example, a linear solenoid valve is used.

<Configuration of drive system>

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

  The engine 2 is provided with an E / G output shaft 21. The E / G output shaft 21 is rotated by the power generated by the engine 2.

  The torque converter 3 includes a pump impeller 31, a turbine runner 32 and a lockup clutch 33. The E / G output shaft 21 is connected to the pump impeller 31, and the pump impeller 31 is integrally rotatably provided around the same rotation axis as the E / G output shaft 21. The turbine runner 32 is rotatably provided about the same rotation axis as the pump impeller 31. The lockup clutch 33 is provided to connect / disconnect the pump impeller 31 and the turbine runner 32 directly. When the lockup clutch 33 is engaged, the pump impeller 31 and the turbine runner 32 are directly coupled, 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 21 is rotated in a state where the lockup clutch 33 is released, the pump impeller 31 is rotated. When the pump impeller 31 rotates, a flow of oil from the pump impeller 31 toward the turbine runner 32 is generated. The flow of oil is received by the turbine runner 32, and the turbine runner 32 rotates. At this time, an amplification action of the torque converter 3 occurs, and a power larger than the power (torque) of the E / G output shaft 21 is generated in the turbine runner 32.

  With the lockup clutch 33 engaged, when the E / G output shaft 21 is rotated, the E / G output shaft 21, the pump impeller 31 and the turbine runner 32 rotate integrally.

  An oil pump 5 is provided between the torque converter 3 and the power split type continuously variable transmission 4. The pump shaft of the oil pump 5 is rotatably provided integrally with the pump impeller 31. Thus, when the pump impeller 31 is rotated by the power of the engine 2, the pump shaft of the oil pump 5 is rotated, and the oil is discharged from the oil pump 5.

  Power split type continuously variable transmission 4 transmits the power input from torque converter 3 to differential gear 6. The power split type continuously variable transmission 4 includes an input shaft 41, an output shaft 42, a continuously variable transmission mechanism 43, a constant transmission mechanism 44, and an output gear mechanism 45.

  The input shaft 41 is connected to the turbine runner 32 of the torque converter 3 and provided integrally rotatably around the same rotation axis as the turbine runner 32.

  The output shaft 42 is provided in parallel with the input shaft 41.

  The continuously variable transmission mechanism 43 has a configuration similar to that of a known belt-type continuously variable transmission (CVT). Specifically, the continuously variable transmission mechanism 43 has a primary shaft 51 connected to the input shaft 41, a secondary shaft 52 provided parallel to the primary shaft 51, and a primary rotatably supported by the primary shaft 51 relative to each other. A pulley 53, a secondary pulley 54 supported against relative rotation on the secondary shaft 52, and a belt 55 wound around the primary pulley 53 and the secondary pulley 54 are provided.

  Primary pulley 53 is disposed opposite to fixed sheave 61 fixed to primary shaft 51 and fixed sheave 61 with belt 55 interposed therebetween, and movable sheave supported on primary shaft 51 so as to be movable in the axial direction and to be relatively non-rotatable. And 62. A cylinder 63 fixed to the primary shaft 51 is provided on the opposite side of the movable sheave 62 with respect to the fixed sheave 61, and an oil chamber 64 is formed between the movable sheave 62 and the cylinder 63.

  Secondary pulley 54 is disposed opposite to fixed sheave 65 fixed to secondary shaft 52 and fixed sheave 65 with belt 55 interposed therebetween, and movable sheave supported on secondary shaft 52 so as to be movable in the axial direction and to be relatively non-rotatable. It has 66 and. A cylinder 67 fixed to the secondary shaft 52 is provided on the opposite side to the fixed sheave 61 with respect to the movable sheave 66, and an oil chamber 68 is formed between the movable sheave 66 and the cylinder 67.

In the continuously variable transmission mechanism 43, the hydraulic pressure supplied to the oil chamber 64 of the primary pulley 53 and the oil chamber 68 of the secondary pulley 54 is controlled to change the groove widths of the primary pulley 53 and the secondary pulley 54. belt speed ratio gamma _b is changed continuously steplessly.

More specifically, when the belt speed ratio gamma _b is lowered, the hydraulic pressure is raised to be supplied to the oil chamber 64 of the primary pulley 53. As a result, the movable sheave 62 of the primary pulley 53 moves toward the fixed sheave 61, and the distance (groove width) between the fixed sheave 61 and the movable sheave 62 decreases. Along with this, the winding diameter of the belt 55 with respect to the primary pulley 53 is increased, and the distance (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 secondary pulley 54 is reduced, the belt speed ratio gamma _b decreases.

When the belt speed ratio gamma _b is raised, the hydraulic pressure is lowered to be supplied to the oil chamber 64 of the primary pulley 53. As a result, the thrust of secondary pulley 54 relative to belt 55 becomes larger than the thrust of primary pulley 53 relative to belt 55, and the distance between fixed sheave 65 and movable sheave 66 of secondary pulley 54 becomes smaller, and fixed sheave 61 and movable sheave The distance to 62 increases. As a result, the pulley ratio between the primary pulley 53 and secondary pulley 54 increases, the belt speed ratio gamma _b increases.

  On the other hand, the thrusts of the primary pulley 53 and the secondary pulley 54 need 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 supplied to the oil chamber 64 of the primary pulley 53 and the oil chamber 68 of the secondary pulley 54 is controlled so that a thrust corresponding to the magnitude of the torque input to the input shaft 41 can be obtained.

  The constant speed change mechanism 44 includes a planetary gear mechanism 71, a split drive gear 72, a split driven gear 73, and an idle gear 74.

  The planetary gear mechanism 71 includes a sun gear 75, a carrier 76 and a ring gear 77. The sun gear 75 is fitted on the input shaft 41 so as to be relatively rotatable. The carrier 76 is supported by the input shaft 41 so as not to be relatively rotatable. The carrier 76 rotatably supports a plurality of pinion gears 78. The plurality of pinion gears 78 are disposed on the circumference and mesh with the sun gear 75. The ring gear 77 has an annular shape surrounding the periphery of the carrier 76, and is engaged with each pinion gear 78 from the outside in the rotational radial direction of the input shaft 41.

  The split drive gear 72 is provided integrally rotatably with the sun gear 75.

  The split driven gear 73 is provided on the outer periphery of the carrier 82 of the output gear mechanism 45 described below so as to be integrally rotatable with the carrier 82. That is, the constant speed change mechanism 44 is connected to the carrier 82 of the output gear mechanism 45.

  The idle gear 74 meshes with the split drive gear 72 and the split driven gear 73.

  The output gear mechanism 45 has a configuration of a planetary gear mechanism. That is, the output gear mechanism 45 includes a sun gear 81, a carrier 82 and a ring gear 83. The sun gear 81 is externally fitted to the secondary shaft 52 so as not to be relatively rotatable. The secondary shaft 52 of the continuously variable transmission mechanism 43 is relatively rotatably inserted into the center of the carrier 82. The carrier 82 rotatably supports the plurality of pinion gears 84. The plurality of pinion gears 84 are disposed on the circumference and mesh with the sun gear 81. The ring gear 83 has an annular shape surrounding the periphery of the carrier 82, and is engaged with each pinion gear 84 from the outside in the rotational radial direction of the secondary shaft 52. Further, one end of an output shaft 42 is connected to the ring gear 83, and the ring gear 83 is integrally provided rotatably around the same rotation axis as the output shaft 42. At the other end of the output shaft 42, an output gear 85 is supported so as not to rotate relatively.

  The rotation of the output gear 85 is transmitted to the differential gear 6 via the first idle gear 86, the idle shaft 87 and the second idle gear 88. The first idle gear 86 is non-rotatably supported by the idle shaft 87 and meshes with the output gear 85. The idle shaft 87 is provided in parallel with the output shaft 42. The second idle gear 88 is non-rotatably supported by the idle shaft 87 and meshes with a ring gear 91 provided on the differential gear 6.

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

  The low clutch C1 is switched between an engaged state (on) in which the output shaft 42 and the secondary shaft 52 are directly connected and a released state (off) in which the direct connection is released.

  The reverse brake B1 is switched to an engaged state (on) in which the split drive gear 72 (sun gear 75) is braked and a released state (off) in which the split drive gear 72 is allowed to rotate.

  The high brake B2 is switched to an engagement state (on) for braking the ring gear 77 and a release state (off) for allowing the ring gear 77 to rotate.

<Power transmission mode>

FIG. 3 is a view showing the states of the low clutch C1, the reverse brake B1 and the high brake B2 when the vehicle 1 is moving forward and backward. Figure 4 is a diagram showing a relationship between the gear ratio of the belt speed ratio gamma _b power split type continuously variable transmission 4 (hereinafter referred to as "unit speed ratio".) And gamma _u.

  In FIG. 3, "o" indicates that the low clutch C1, the reverse brake B1 and the high brake B2 are in the engaged state. In the P range and the N range, the low clutch C1, the reverse brake B1 and the high brake B2 are released.

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

  In the belt mode, the high brake B2 and the reverse brake B1 are released, and the low clutch C1 is engaged. As a result, the split drive gear 72, the split driven gear 73 and the idle gear 74 of the fixed transmission mechanism 44, and the carrier 82 of the output gear mechanism 45 become free (free rotation), and the output shaft 42 and the secondary shaft 52 are directly coupled. .

The power input to the input shaft 41 is transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43 and causes the primary shaft 51 and the primary pulley 53 to rotate. 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 low clutch C1 is engaged, the output shaft 42 rotates integrally with the secondary shaft 52. Therefore, the belt modes, as shown in FIG. 4, the unit gear ratio gamma _u coincides with the belt speed ratio gamma _b.

  The rotation of the output shaft 42 is transmitted to the ring gear 91 of the differential gear 6 via the output gear 85, the first idle gear 86, the idle shaft 87 and the second idle gear 88. Thereby, the drive shafts 92 and 93 of the vehicle 1 rotate in the forward direction.

  FIG. 5 is a collinear diagram showing the relationship of the rotational speeds of the carrier 82 of the output gear mechanism 45, the sun gear 81 and the ring gear 83. As shown in FIG.

  In the split mode, as shown in FIG. 3, the high brake B2 is engaged, and the reverse brake B1 and the low clutch C1 are released. By engaging the high brake B2, the ring gear 77 of the constant speed change mechanism 44 is braked. Further, the direct coupling between the output shaft 42 and the secondary shaft 52 is released by releasing the low clutch C1.

  The power input to the input shaft 41 is transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43 and causes the primary shaft 51 and the primary pulley 53 to rotate. 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 rotation of the secondary shaft 52 causes the sun gear 81 of the output gear mechanism 45 to rotate.

  Further, since the ring gear 77 of the constant speed change mechanism 44 is braked, the power input to the input shaft 41 revolves the carrier 76 of the constant speed change mechanism 44 and rotates the pinion gear 78 held by the carrier 76. Let As the pinion gear 78 rotates, power is input from the pinion gear 78 to the sun gear 75. Thereby, the pinion gear 78 and the split drive gear 72 rotate. The rotation of the split drive gear 72 is transmitted to the split driven gear 73 through the idle gear 74 to rotate the split driven gear 73 and the carrier 82 of the output gear mechanism 45.

Since the transmission gear ratio (hereinafter referred to as “split transmission ratio”) γ _{g of the} fixed transmission mechanism 44 is constant and unchanged (fixed), in the split mode, if the power input to the input shaft 41 is constant, the output gear The rotation of the carrier 82 of the mechanism 45 is maintained at a constant speed. Therefore, when the belt speed ratio gamma _b raised, output the rotational speed of the sun gear 81 of the gear mechanism 45 is lowered, as shown in FIG. 5 by two-dot chain line, the ring gear 83 of the output gear mechanism 45 (the output shaft 42 ) Rotation speed is increased. As a result, in the split mode, as shown in FIG. 4, as the belt speed ratio gamma _b is large, the unit gear ratio gamma _u is reduced.

  The rotation of the output shaft 42 is transmitted to the ring gear 91 of the differential gear 6 via the output gear 85, the first idle gear 86, the idle shaft 87 and the second idle gear 88. Thereby, the drive shafts 92 and 93 of the vehicle 1 rotate in the forward direction.

  In the R range, as shown in FIG. 3, the high brake B2 and the low clutch C1 are released. Then, the reverse brake B1 is engaged. Thereby, the split drive gear 72 (sun gear 75) is braked. By braking the split drive gear 72, the idle gear 74 of the fixed transmission mechanism 44 can not rotate, and the split driven gear 73 and the carrier 82 can not rotate.

  The power input to the input shaft 41 is transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43 and causes the primary shaft 51 and the primary pulley 53 to rotate. 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 rotation of the secondary shaft 52 causes the sun gear 81 of the output gear mechanism 45 to rotate. Since the carrier 82 can not rotate, the ring gear 83 rotates in the opposite direction to the sun gear 81 when the sun gear 81 rotates, as shown by a one-dot chain line in FIG. The rotation direction of the ring gear 83 is opposite to the rotation direction of the ring gear 83 in the D range (belt mode and split mode). Then, the output shaft 42 rotates integrally with the ring gear 83. The rotation of the output shaft 42 is transmitted to the ring gear 91 of the differential gear 6 via the output gear 85, the first idle gear 86, the idle shaft 87 and the second idle gear 88. Thereby, the drive shafts 92 and 93 of the vehicle 1 rotate in the reverse direction.

<Kickdown control>

  FIG. 6 is a timing chart for explaining the kick down control.

The memory of the transmission ECU12 is shift line that defines the unit gear ratio gamma _u corresponding to the vehicle speed and the accelerator pedal opening are stored are mapped. When the accelerator pedal is depressed, the transmission ECU 12, the accelerator opening is obtained from the engine ECU 11, according to a shift line map, the unit gear ratio gamma _u corresponding to the accelerator opening and the vehicle speed is set as the target unit transmission ratio. The vehicle speed may be calculated from the output rotation speed, or may be calculated from the frequency of a pulse signal input from the vehicle speed sensor provided with a vehicle speed sensor.

Then, the transmission ECU 12, based on the target unit gear ratio, principal kickdown control with switching from the split mode to the belt modes, as well as changes in the belt speed ratio gamma _b (hereinafter, simply referred to as "kick down control".) No is determined (K / D determination). Specifically, when the target unit gear ratio is larger than the split gear ratio gamma _g, it is determined that it is necessary to kick down control, when the target unit gear ratio is equal to or less than the split speed ratio gamma _g, the kick down control Is determined to be unnecessary. If it is determined that the kick down control is necessary, the kick down control is started (time T1).

  Switching from the split mode to the belt mode is achieved by switching (gripping) between the low clutch C1 and the high brake B2. That is, switching from the split mode to the belt mode is achieved by releasing the high brake B2 engaged in the split mode and engaging the low clutch C1 released in the split mode.

  Therefore, in the kick down control, first, the transmission ECU 12 starts the release control for releasing the high brake B2 (time T1). In the release control, the release instruction pressure of the high brake B2 is lowered with the lapse of time. The release instruction pressure is a target value of the hydraulic pressure supplied to the high brake B2, and corresponds to the current value input to the hydraulic control valve for the high brake B2.

Further, the transmission ECU 12, the shift control for changing the belt speed ratio gamma _b is started (time T1). The shift control hydraulic pressure is controlled to be supplied to the primary pulley 53 and secondary pulley 54, after which the belt speed ratio gamma _b is lowered to the vicinity of the split speed ratio gamma _g, belt gear ratio gamma _b until the target unit gear ratio It is raised.

  Then, after the start of the kick down control, if the execution of the first fill is determined in the fill timing determination process shown in FIG. 7, then the transmission ECU 12 performs the engagement control for engaging the low clutch C1. It is started (time T2).

  In the engagement control, fast fill control is performed in which the engagement command pressure is maintained at a constant pressure higher than the initial pressure over a predetermined time (time T2 to T3) after the start of the engagement control. The engagement command pressure is a target value of the hydraulic pressure supplied to the low clutch C1, and corresponds to the current value input to the hydraulic control valve for the low clutch C1. By the first fill control, the low clutch C1 can be filled with oil, and the responsiveness of the low clutch C1 can be improved.

  Following the fast fill control, after the engagement command pressure is maintained at the initial pressure for a predetermined time (time T3 to T4), next, the engagement command pressure is increased by a constant time gradient (time change rate). Control is started (time T4). By this sweep control, the hydraulic pressure supplied to the low clutch C1 is increased.

  During the sweep control, when the low clutch C1 is almost completely engaged and the engagement command pressure rises to the maximum pressure, the engagement of the low clutch C1 is completed and the engagement control is ended (time T5). . Further, after the end of the engagement control, the release instruction pressure is lowered to 0, and the release control is ended (time T6).

  FIG. 7 is a flowchart showing the flow of fill timing determination processing.

  During the execution of the kick down control, the transmission ECU 12 repeatedly executes the fill timing determination process.

In Fill timing determination process based on the current of the unit gear ratio gamma _u and the target unit gear ratio, the flow rate of the oil necessary to change the belt speed ratio gamma _b is calculated. In addition, the flow rate of oil necessary for the engagement of the low clutch C1 is calculated based on the engagement command pressure. And the sum total of those flow rates is calculated as a required flow rate (step S1).

  Further, the flow rate of oil discharged from the oil pump 5 is calculated as the supply flow rate (step S2). Since the oil pump 5 is driven by the power of the engine 2, the capacity (supply flow rate) of the oil pump 5 depends on the current engine speed. Therefore, the current engine speed is acquired from the engine ECU 11, and the supply flow rate of the oil pump 5 at that engine speed is calculated.

  Thereafter, the required flow rate and the supply flow rate are compared. Then, it is determined whether the supply flow rate exceeds the required flow rate (step S3).

  If the supply flow rate exceeds the required flow rate (YES in step S3), the execution of the fast fill control is determined (step S4), and the fill timing determination process is ended. Thus, the supply of the hydraulic pressure to the low clutch C1 can be started while the supply flow rate exceeds the required flow rate.

On the other hand, when the supply flow rate is equal to or less than the required flow rate (NO in step S3), the time required for the unit gear ratio γ _u to match the target unit gear ratio from the current time (shift remaining time) is calculated It is determined whether it is longer than the time (clutch response time) required from the engagement start of the low clutch C1 to the engagement completion (step S5).

As shown in FIG. 6, the unit gear ratio gamma _u is increased by changing the belt speed ratio gamma _b, with increasing unit gear ratio gamma _u, turbine speed increases. If the target unit gear ratio is larger than the split gear ratio gamma _g, the target unit gear ratio, a final target value of the belt speed ratio gamma _b in the shift control. Thus, the unit gear ratio gamma _u is at the time of the match with the target unit transmission ratio, and a belt speed ratio gamma value and the turbine speed multiplied by the output rotation speed _b are matched. Shifting the remaining time can be calculated from the difference between the value obtained by multiplying the output rotation speed to the current belt speed ratio gamma _b and the current turbine speed (estimated).

  The turbine speed is the same as the speed of the input shaft 41. Further, since the primary shaft 51 is connected to the input shaft 41 and the primary pulley 53 is supported by the primary shaft 51 so as to be relatively non-rotatable, the turbine rotational speed is the same as the primary rotational speed.

  The clutch response time is stored in the memory of the transmission ECU 12 as a constant.

  If the shift remaining time is larger than the clutch response time (YES in step S5), the execution of the fast fill control is not determined, and the fill timing determination process is ended.

  If the shift remaining time is equal to or less than the clutch response time (NO in step S5), the execution of the fast fill control is determined (step S4), and the fill timing determination process is ended. Thus, the engagement of the low clutch C1 can be completed before the shift control ends.

<Function effect>

As described above, when the execution of the kick down control with the switching from the split mode to the belt mode is determined, in response to the decision, change the belt speed ratio gamma _b is started. On the other hand, the the belt speed change ratio oil necessary to modify the gamma _b flow is calculated as the total flow rate required for the oil flow rate required engagement of low clutch C1 for switching from the split mode to the belt mode Ru. Further, the flow rate of oil discharged from the oil pump 5 is calculated as the supply flow rate. Then, the required flow rate and the supply flow rate are compared, and when the supply flow rate exceeds the required flow rate, the supply of the hydraulic pressure to the low clutch C1 is started.

This can suppress the shortage on the flow rate of the oil occurs, it is possible to improve the controllability of the kick down control with the switching from the split mode to the belt modes, as well as changes in the belt speed ratio gamma _b.

<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 embodiment, the required flow rate and the supply flow rate are compared, and it is determined that the execution of the fast fill control is determined if the supply flow rate exceeds the required flow rate. However, the predetermined flow rate is added to the required flow rate, the added value is compared with the supplied flow rate, and if the supplied flow rate exceeds the added value of the required flow rate and the flow rate, execution of fast fill control is determined. May be As a result, the occurrence of the shortage in the flow rate of oil can be further suppressed, and the controllability of the kick down control can be further improved.

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

1 Vehicle 2 Engine (Drive Source)
4 power split type continuously variable transmission 5 oil pump 12 transmission ECU (determination means, shift control means, discharge flow rate calculation means, necessary flow rate calculation means, engagement control means)
41 Input axis (input axis)
42 Output Axis (Output Axis)
43 continuously variable transmission mechanism 44 constant transmission mechanism 45 output gear mechanism C1 low clutch (engagement element)

Claims (1)

Driving source,
An oil pump driven by the drive source;
An input shaft to which power from the drive source is input, a belt-type continuously variable transmission mechanism for continuously changing the power input to the input shaft by changing the belt transmission ratio, the power to be input to the input shaft It comprises an engagement element which certain transmission mechanism, an output gear mechanism outputs to the output shaft of the power, and the oil pump is engaged by hydraulic pressure generated to shift at a constant split speed ratio, engagement of the engaging element Thus, from the split mode in which the power input to the input shaft is transmitted to the output gear mechanism via the continuously variable transmission mechanism and the constant transmission mechanism, the power input to the input shaft is continuously variable A control device that is used in a vehicle equipped with a power split type continuously variable transmission that switches to a belt mode that is transmitted to the output gear mechanism via a mechanism and controls the power split type continuously variable transmission,
Determining means for determining execution of kickdown control accompanied by switching from the split mode to the belt mode together with the change of the belt transmission ratio;
Shift control means for starting to change the belt transmission ratio by controlling the hydraulic pressure supplied to the continuously variable transmission mechanism in response to the determination of execution of the kickdown control;
Discharge flow rate calculation means for calculating the flow rate of oil discharged from the oil pump as a supply flow rate ;
Required flow rate calculation means for calculating the sum of the flow rate of oil required to change the belt transmission ratio and the flow rate of oil required to engage the engagement element as the required flow rate;
After the execution of the kickdown control is determined, the supply flow rate calculated by the discharge flow rate calculation means is compared with the required flow rate calculated by the required flow rate calculation means, and the supply flow rate is calculated for the required flow rate. And (c) engaging control means for starting supply of hydraulic pressure to the engaging element when it is exceeded .

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