JP2018173155A - Control device of transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of a transmission capable of suppressing occurrence of belt slip in switching modes.SOLUTION: In switching a mode from a split mode to a belt mode, a transmission torque capacity of a clutch C1 at a release side is lowered (T1) in a stage when differential rotation (rotating speed difference between secondary rotating speed and output rotating speed) occurs at both sides of a clutch C2 at an engagement side. Thus the clutch C1 is kept in a half clutch state, slip occurs in the clutch C1, rotation at a continuously variable transmission mechanism side is blown up, and the differential rotation at both sides of the clutch C2 is rapidly reduced. When the differential rotation is reduced to a prescribed value, a transmission torque capacity of the clutch C2 is increased (T2). Before the transmission torque capacity of the clutch C2 is increased, a belt compression pressure of the continuously variable transmission mechanism is increased higher than a necessary compression pressure.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a transmission control device 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

  In the transmission, the applicant has also proposed a configuration in which the power of the drive source is divided into two systems and transmitted.

  The configuration according to the proposal includes a continuously variable transmission mechanism, a split transmission mechanism (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 split transmission mechanism includes a split drive gear that transmits / shuts 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.

  In this transmission, a belt mode and a split mode are provided as power transmission modes during forward traveling.

  In the belt mode, the first clutch that switches transmission / disconnection of power between the input shaft and the split drive gear is released, the split drive gear is freely rotated (free), and the carrier of the planetary gear mechanism is free. Rotated. Further, the second clutch for coupling / separating the sun gear and the ring gear of the planetary gear mechanism is engaged, and the sun gear and the ring gear are coupled. 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 unit speed ratio, which is the speed ratio of the entire transmission (the rotational speed of the input shaft / the rotational speed of the output shaft), matches the speed ratio (belt speed ratio) of the continuously variable transmission mechanism.

  In the split mode, the second clutch is released, and the coupling 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, the first clutch is engaged, 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 to a constant split gear ratio. Input to the carrier. 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.

  When the unit transmission ratio is changed across the split transmission ratio, the change of the unit transmission ratio involves switching between the belt mode and the split mode. This mode switching is achieved by switching the engagement between the first clutch and the second clutch. In a state where the belt speed ratio and the split speed ratio are deviated, a differential rotation occurs between the sun gear and the carrier. Therefore, the belt speed ratio is changed by splitting the engagement between the first clutch and the second clutch. If it is performed at the time of shifting to a gear ratio that substantially matches the ratio (synchronous point or its vicinity), it is possible to prevent the occurrence of a gear shift shock due to differential rotation.

  However, when kickdown is required due to the accelerator pedal being depressed quickly and greatly in split mode, the engagement between the first clutch and the second clutch is switched after the belt speed ratio is changed to the split speed ratio. As a result, the shift response is poor. Therefore, when kickdown is required, the transmission torque capacity of the first clutch is lowered and the first clutch is slid to blow up the rotation (sun gear rotation) output from the continuously variable transmission mechanism. When the differential rotation between the rotation and the output shaft rotation (rotation of the ring gear) ceases, the second clutch is engaged.

  However, there is a large difference in rotation between the sun gear and the ring gear due to variations in the command pressure and actual pressure for engaging the second clutch, the clutch clearance of the second clutch, and variations in the time required to eliminate it. There is a case where the second clutch is engaged in a state where the occurrence of the occurrence of the problem occurs. In this case, there is a concern that an inertia torque occurs on the belt and the belt slips.

  The objective of this invention is providing the control apparatus of a transmission which can suppress generation | occurrence | production of the belt slip at the time of mode switching.

  In order to achieve the above object, a transmission control apparatus according to the present invention includes an input shaft, an output shaft, a belt-type continuously variable transmission mechanism for continuously changing power input to the input shaft, and a continuously variable transmission. A first engagement element interposed in a first path for transmitting power between the mechanism and the output shaft, and a second path for transmitting power between the continuously variable transmission mechanism and the output shaft. A first mode is configured by the engagement of the first engagement element and the release of the second engagement element, and the first mode is established by the release of the first engagement element and the engagement of the second engagement element. In a vehicle equipped with a transmission configured to prevent differential rotation between the first engagement element and the second engagement element when the two-mode is configured and the speed ratio of the continuously variable transmission mechanism takes a constant value A control device for controlling the transmission, the first engagement element and the second At the time of switching between the first mode and the second mode by switching the engagement with the combined element, in the state where the differential rotation has occurred in the first engagement element or the second engagement element on the engagement side, A release control means for reducing the transmission torque capacity of the second engagement element or the first engagement element; and after the transmission torque capacity of the second engagement element or the first engagement element on the release side is reduced, The transmission torque capacity of the first engagement element or the second engagement element on the engagement side is increased in response to the differential rotation occurring in the first engagement element or the second engagement element being reduced to a predetermined value. The engagement control means to be engaged, and at least the first engagement element on the engagement side or the second from the point when the differential rotation generated in the first engagement element or the second engagement element on the engagement side is reduced to a predetermined value. The belt clamping pressure of the continuously variable transmission mechanism is required according to the gear ratio until the engagement element is engaged. Increase than clamping to including a clamping pressure control unit.

  According to this configuration, at the time of switching between the first mode and the second mode by switching the engagement between the first engagement element and the second engagement element, first, a differential rotation is performed on the engagement element on the engagement side. At the stage where the occurrence occurs, the transmission torque capacity of the engagement element on the release side is lowered. As a result, the disengagement-side engagement element is in a half-clutch state, slippage occurs in the disengagement-side engagement element, rotation on the continuously variable transmission mechanism side blows up, and occurs in the engagement-side engagement element. The differential rotation is rapidly reduced.

  When the differential rotation generated in the engagement element on the engagement side is reduced to a predetermined value, the transmission torque capacity of the engagement element on the engagement side is increased. At this time, at least the period from when the differential rotation generated in the engagement element on the engagement side is reduced to a predetermined value until the engagement element on the engagement side is engaged is the belt clamping pressure of the continuously variable transmission mechanism. Is increased from the required clamping pressure according to the gear ratio. Thereby, even if the engagement element on the engagement side is completely engaged in a state where the differential rotation generated in the engagement element on the engagement side is large, the occurrence of belt slip due to the inertia torque can be suppressed.

  According to the present invention, the occurrence of belt slip at the time of mode switching can be suppressed. In addition, since the differential rotation generated in the first engagement element or the second engagement element on the engagement side at the time of mode switching can be rapidly reduced, the time required for mode switching can be shortened.

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 each engagement element with which a transmission is equipped. It is a collinear diagram which shows the relationship of the rotation speed (rotation speed) of the sun gear of the planetary gear mechanism with which a transmission is equipped, a carrier, and a ring gear. It is a figure which shows the relationship between the gear ratio (belt gear ratio) of the continuously variable transmission mechanism with which a transmission is equipped, and the gear ratio (unit gear ratio) of the whole power division type continuously variable transmission. It is a figure which shows the structure of the control system which concerns on one Embodiment of this invention. Secondary speed, output speed, hydraulic pressure supplied to clutches C1, C2, engine torque, belt transmission torque capacity (necessary clamping pressure, marginal clamping pressure), and clutch C1 at the time of mode switching from split mode to belt mode , C2 is a diagram showing a time change of each transmission torque capacity of C2.

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

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

  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 power of the engine 2 is transmitted to the differential gear 5 via the torque converter 3 and the transmission 4, and is transmitted from the differential gear 5 to the left and right drive wheels 7L and 7R via the left and right drive shafts 6L and 6R, respectively. .

  The engine 2 includes an E / G output shaft 11. The E / G output shaft 11 is rotated by the power generated by the engine 2.

  The torque converter 3 includes a pump impeller 21, a turbine runner 22, and a lockup clutch (lockup mechanism) 23. An E / G output shaft 11 is connected to the pump impeller 21, and the pump impeller 21 is provided so as to be integrally rotatable about the same rotation axis as the E / G output shaft 11. The turbine runner 22 is provided to be rotatable about the same rotation axis as the pump impeller 21. The lockup clutch 23 is provided to directly connect / separate the pump impeller 21 and the turbine runner 22. When the lockup clutch 23 is engaged, the pump impeller 21 and the turbine runner 22 are directly connected, and when the lockup clutch 23 is released, the pump impeller 21 and the turbine runner 22 are separated.

  When the E / G output shaft 11 is rotated in a state where the lockup clutch 23 is released, the pump impeller 21 is rotated. When the pump impeller 21 rotates, an oil flow from the pump impeller 21 toward the turbine runner 22 is generated. The oil flow is received by the turbine runner 22 and the turbine runner 22 rotates. At this time, the amplifying action of the torque converter 3 occurs, and the turbine runner 22 generates power that is greater than the power (torque) of the E / G output shaft 11.

  In a state where the lock-up clutch 23 is engaged, when the E / G output shaft 11 is rotated, the E / G output shaft 11, the pump impeller 21, and the turbine runner 22 are rotated together.

  The transmission 4 includes an input shaft 31 and an output shaft 32, and is configured to transmit power to the output shaft 32 by dividing the power input to the input shaft 31 into two systems. Formula) transmission. The transmission 4 includes a continuously variable transmission mechanism 33, a reverse gear mechanism 34, a planetary gear mechanism 35, and a split transmission mechanism 36 in order to configure two systems of power transmission paths.

  The input shaft 31 is connected to the turbine runner 22 of the torque converter 3 and is provided so as to be integrally rotatable about the same rotation axis as the turbine runner 22.

  The output shaft 32 is provided in parallel with the input shaft 31. An output gear 37 is supported on the output shaft 32 so as not to be relatively rotatable. The output gear 37 meshes with the differential gear 5 (ring gear of the differential gear 5).

  The continuously variable transmission mechanism 33 has the same configuration as a known belt-type continuously variable transmission (CVT). Specifically, the continuously variable transmission mechanism 33 includes a primary shaft 41, a secondary shaft 42 provided in parallel with the primary shaft 41, a primary pulley 43 supported by the primary shaft 41 so as not to be relatively rotatable, and a secondary shaft 42. And a secondary pulley 44 supported so as not to be relatively rotatable, and a primary pulley 43 and a belt 45 wound around the secondary pulley 44.

  The primary pulley 43 is disposed so as to face the fixed sheave 51 fixed to the primary shaft 41 and the fixed sheave 51 with the belt 45 interposed therebetween, and is supported by the primary shaft 41 so as to be movable in the axial direction and not to be relatively rotatable. (Primary sheave) 52. A cylinder 53 fixed to the primary shaft 41 is provided on the opposite side of the movable sheave 52 from the fixed sheave 51, and a hydraulic chamber 54 is formed between the movable sheave 52 and the cylinder 53.

  The secondary pulley 44 is disposed so as to face the fixed sheave 55 fixed to the secondary shaft 42 with the belt 45 sandwiched between the fixed sheave 55 and is supported by the secondary shaft 42 so as to be movable in the axial direction but not to be relatively rotatable. (Secondary sheave) 56. A cylinder 57 fixed to the secondary shaft 42 is provided on the opposite side of the movable sheave 56 to the fixed sheave 55, and a hydraulic chamber 58 is formed between the movable sheave 56 and the cylinder 57. In the rotation axis direction, the positional relationship between the fixed sheave 55 and the movable sheave 56 is reversed from the positional relationship between the fixed sheave 51 and the movable sheave 52 of the primary pulley 43.

  In the continuously variable transmission mechanism 33, the hydraulic pressure supplied to the hydraulic chambers 54 and 58 of the primary pulley 43 and the secondary pulley 44 is controlled, and the groove widths of the primary pulley 43 and the secondary pulley 44 are changed, so that the primary The pulley ratio between the pulley 43 and the secondary pulley 44 is continuously changed steplessly.

  Specifically, when the pulley ratio is decreased, the hydraulic pressure supplied to the hydraulic chamber 54 of the primary pulley 43 is increased. As a result, the movable sheave 52 of the primary pulley 43 moves to the fixed sheave 51 side, and the interval (groove width) between the fixed sheave 51 and the movable sheave 52 is reduced. Accordingly, the winding diameter of the belt 45 around the primary pulley 43 is increased, and the interval (groove width) between the fixed sheave 55 and the movable sheave 56 of the secondary pulley 44 is increased. As a result, the pulley ratio between the primary pulley 43 and the secondary pulley 44 is reduced.

  When the pulley ratio is increased, the hydraulic pressure supplied to the hydraulic chamber 54 of the primary pulley 43 is reduced. As a result, the thrust ratio, which is the ratio of the thrust (primary thrust) of the primary pulley 43 to the thrust of the secondary pulley 44 (secondary thrust), is reduced, and the distance between the fixed sheave 55 and the movable sheave 56 of the secondary pulley 44 is reduced. The interval between the fixed sheave 51 and the movable sheave 52 is increased. As a result, the pulley ratio between the primary pulley 43 and the secondary pulley 44 is increased.

  On the other hand, the thrust of the primary pulley 43 and the secondary pulley 44 needs to be large enough to prevent slippage between the primary pulley 43 and the secondary pulley 44 and the belt 45. Therefore, the hydraulic pressure supplied to the hydraulic chamber 58 of the secondary pulley 44 is controlled so that a thrust according to the magnitude of the torque input to the input shaft 31 is obtained.

  The reverse gear mechanism 34 is configured to transmit the power input to the input shaft 31 to the primary shaft 41 by reversely rotating and decelerating. Specifically, the reverse gear mechanism 34 has an input shaft gear 61 that is supported on the input shaft 31 so as not to rotate relative to the input shaft 31, and has a larger diameter and a larger number of teeth than the input shaft gear 61. A primary shaft gear 62 that is supported so as not to be relatively rotatable and meshes with the input shaft gear 61 is included.

  The planetary gear mechanism 35 includes a sun gear 71, a carrier 72, and a ring gear 73. The sun gear 71 is supported on the secondary shaft 42 so as not to be relatively rotatable by spline fitting. The carrier 72 is fitted on the output shaft 32 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 outside in the rotational radial direction of the secondary shaft 42. An output shaft 32 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 32.

  Split transmission mechanism 36 includes a split drive gear 81 and a split driven gear 82 that meshes with split drive gear 81.

  The split drive gear 81 is fitted on the input shaft 31 so as to be relatively rotatable.

  The split driven gear 82 is provided so as to be integrally rotatable about the same rotation axis as the carrier 72 of the planetary gear mechanism 35. The split driven gear 82 has a smaller diameter than the split drive gear 81 and has a smaller number of teeth than the split drive gear 81.

  The transmission 4 includes clutches C1 and C2 and a brake B1.

  The clutch C1 is switched between an engaged state in which the input shaft 31 and the split drive gear 81 are directly connected (coupled so as to be integrally rotatable) and a released state in which the direct connection is released.

  The clutch C2 is switched between an engaged state in which the sun gear 71 and the ring gear 73 of the planetary gear mechanism 35 are directly coupled (coupled so as to be integrally rotatable) and a released state in which the direct coupling is released.

  The brake B1 is switched between an engagement state in which the carrier 72 of the planetary gear mechanism 35 is braked and a release state in which the rotation of the carrier 72 is allowed.

<Transmission mode>
FIG. 2 is a diagram illustrating states of the clutches C1 and C2 and the brake B1 when the vehicle 1 moves forward and backward. FIG. 3 is a collinear diagram showing the relationship between the rotational speeds (rotational speeds) of the sun gear 71, the carrier 72 and the ring gear 73 of the planetary gear mechanism 35. FIG. 4 shows a belt transmission ratio that is a transmission ratio by the continuously variable transmission mechanism 33 and a unit transmission ratio that is the overall transmission ratio of the transmission 4, that is, a unit that is a rotation speed ratio between the input shaft 31 and the output shaft 32. It is a figure which shows the relationship with a gear ratio.

  In FIG. 2, “◯” indicates that the clutches C1 and C2 and the brake B1 are engaged. “X” indicates that the clutches C1 and C2 and the brake B1 are in the released state.

  The transmission 4 has a belt mode and a split mode as transmission modes when the vehicle 1 moves forward. The belt mode and the split mode are switched by switching between the state in which the clutch C1 is engaged and the state in which the clutch C2 is engaged (replacement of the clutches C1 and C2).

  In the belt mode, as shown in FIG. 2, the clutch C1 and the brake B1 are released, and the clutch C2 is engaged. As a result, the split drive gear 81 is disconnected from the input shaft 31, the carrier 72 of the planetary gear mechanism 35 becomes free (free rotation state), and the sun gear 71 and the ring gear 73 of the planetary gear mechanism 35 are directly connected.

  The power input to the input shaft 31 is reversed and decelerated by the reverse gear mechanism 34 and transmitted to the primary shaft 41 of the continuously variable transmission mechanism 33 to rotate the primary shaft 41 and the primary pulley 43. The rotation of the primary pulley 43 is transmitted to the secondary pulley 44 via the belt 45 to rotate the secondary pulley 44 and the secondary shaft 42. Since the sun gear 71 and the ring gear 73 of the planetary gear mechanism 35 are directly connected, the sun gear 71, the ring gear 73 and the output shaft 32 rotate together with the secondary shaft 42. Therefore, in the belt mode, as shown in FIGS. 3 and 4, the unit speed ratio is changed from the belt speed ratio (the pulley ratio between the primary pulley 43 and the secondary pulley 44 of the continuously variable transmission mechanism 33) to the front speed reduction ratio (input shaft). The number of rotations is equal to the product of (the number of rotations of 31 / the number of rotations of the primary shaft 41).

  In the split mode, as shown in FIG. 2, the clutch C1 is engaged, and the clutch C2 and the brake B1 are released. Thereby, the input shaft 31 and the split drive gear 81 are directly connected, and the rotation of the input shaft 31 can be transmitted to the carrier 72 of the planetary gear mechanism 35 via the split drive gear 81 and the split driven gear 82. The 35 sun gear 71 and the ring gear 73 are separated.

  The power input to the input shaft 31 is reversed and decelerated by the reverse gear mechanism 34 and transmitted to the primary shaft 41 of the continuously variable transmission mechanism 33, and is transmitted from the primary shaft 41 via the primary pulley 43, the belt 45 and the secondary pulley 44. Is transmitted to the secondary shaft 42 and transmitted to the sun gear 71 of the planetary gear mechanism 35. On the other hand, power input to the input shaft 31 is transmitted from the split drive gear 81 through the split driven gear 82 to the carrier 72 of the planetary gear mechanism 35 at an increased speed.

  Since the gear ratio (split gear ratio) between the split drive gear 81 and the split driven gear 82 is constant and unchanged (fixed), the planetary gear mechanism 35 can be used in the split mode if the power input to the input shaft 31 is constant. The rotation of the carrier 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 planetary gear mechanism 35 decreases, so that the rotational speed of the ring gear 73 (output shaft 32) of the planetary gear mechanism 35 as shown by a broken line in FIG. Goes up. As a result, in the split mode, as shown in FIG. 4, the unit transmission ratio of the transmission 4 decreases as the belt transmission ratio of the continuously variable transmission mechanism 33 increases.

  The rotation of the output shaft 32 in the belt mode and the split mode is transmitted to the differential gear 5 via the output gear 37. Thereby, the drive shafts 6L and 6R and the drive wheels 7L and 7R of the vehicle 1 rotate in the forward direction.

  In the reverse mode during reverse travel of the vehicle 1, as shown in FIG. 2, the clutches C1 and C2 are released and the brake B1 is engaged. As a result, the split drive gear 81 is disconnected from the input shaft 31, the sun gear 71 and the ring gear 73 of the planetary gear mechanism 35 are disconnected, and the carrier 72 of the planetary gear mechanism 35 is braked.

  The power input to the input shaft 31 is reversed and decelerated by the reverse gear mechanism 34 and transmitted to the primary shaft 41 of the continuously variable transmission mechanism 33, and is transmitted from the primary shaft 41 via the primary pulley 43, the belt 45 and the secondary pulley 44. Then, the sun gear 71 of the planetary gear mechanism 35 is rotated integrally with the secondary shaft 42. Since the carrier 72 of the planetary gear mechanism 35 is braked, when the sun gear 71 rotates, the ring gear 73 of the planetary gear mechanism 35 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 during forward movement (belt mode and split mode). Then, the output shaft 32 rotates integrally with the ring gear 73. The rotation of the output shaft 32 is transmitted to the differential gear 5 via the output gear 37. Thereby, the drive shafts 6L and 6R and the drive wheels 7L and 7R of the vehicle 1 rotate in the reverse direction.

<Vehicle control system>
FIG. 5 is a block diagram showing the configuration of the control system of the vehicle 1.

  The vehicle 1 includes an ECU (Electronic Control Unit) having a configuration including a microcomputer (microcontroller unit). The microcomputer includes, for example, a CPU, ROM and RAM, data flash (flash memory), and the like. Although only one ECU 101 for controlling the transmission 4 is shown in FIG. 2, a plurality of ECUs having the same configuration as the ECU 101 are mounted on the vehicle 1 in order to control each part. . A plurality of ECUs including the ECU 101 are connected so as to be capable of bidirectional communication using a CAN (Controller Area Network) communication protocol.

  Various sensors necessary for control are connected to the ECU 101. As an example, the ECU 101 includes a primary rotation sensor 111 that outputs a pulse signal synchronized with the rotation of the primary shaft 41 as a detection signal, a secondary rotation sensor 112 that outputs a pulse signal synchronized with the rotation of the secondary shaft 42 as a detection signal, An output rotation sensor 113 that outputs a pulse signal synchronized with the rotation of the output shaft 32 as a detection signal and a detection signal corresponding to the secondary pressure of the transmission 4 (hydraulic pressure acting on the movable sheave 56 of the secondary pulley 44) are output. A hydraulic sensor 114 is connected.

  In the ECU 101, the primary rotational speed (the rotational speed of the primary shaft 41) and the secondary rotational speed (the rotational speed of the secondary shaft 42) are detected from the detection signals of the primary rotational sensor 111, the secondary rotational sensor 112, the output rotational sensor 113 and the hydraulic pressure sensor 114. ), The output rotational speed (the rotational speed of the output shaft 32) and the secondary pressure are acquired. Further, the ECU 101 acquires information from other ECUs. Then, based on information acquired from various sensors by the ECU 101, information input from other ECUs, and the like, each part of the unit including the torque converter 3 and the transmission 4 is controlled for the shift control of the transmission 4 and the like. Various valves and the like included in a hydraulic circuit for supplying hydraulic pressure are controlled.

<Shift control>
The unit gear ratio of the transmission 4 is changed by the control of the belt gear ratio by the ECU 101. In the control of the unit gear ratio, first, a target rotational speed corresponding to the accelerator opening and the vehicle speed is set based on the shift diagram. The shift diagram is a map that defines the relationship between the accelerator opening, the vehicle speed, and the target rotational speed, and is stored in the ROM of the ECU 101. The information on the accelerator opening and the vehicle speed is transmitted from the engine ECU that controls the engine 2 to the ECU 101, for example. When the target rotational speed is set, a target gear ratio that matches the rotational speed input to the input shaft 31 with the target rotational speed is obtained, and a target belt speed ratio corresponding to the target speed ratio is set.

  Next, a secondary thrust necessary to prevent belt slippage in the continuously variable transmission mechanism 33 is set based on the target belt speed ratio and the input torque input to the input shaft 31. The input torque is calculated by multiplying the engine torque by the torque ratio of the torque converter 3. For example, the engine torque is estimated from the accelerator opening and the engine speed by the engine ECU, and transmitted from the engine ECU to the ECU 101. The torque ratio is a torque amplification factor corresponding to the speed ratio of the torque converter 3, and the speed ratio is a divided value obtained by dividing the turbine speed by the engine speed.

  Then, a thrust ratio (= secondary thrust / primary thrust) corresponding to the target belt speed ratio and the input torque is set. Then, the primary thrust is set from the secondary thrust and the thrust ratio.

  Thereafter, based on the set primary thrust and secondary thrust, primary pressure that is the primary pressure that gives the primary thrust to the movable sheave 52 of the primary pulley 43 and secondary pressure that is the hydraulic pressure that gives the secondary thrust to the movable sheave 56 of the secondary pulley 44 A value is set and supplied to the hydraulic chamber 54 of the primary pulley 43 and the hydraulic chamber 58 of the secondary pulley 44 so that the deviation between the target belt speed ratio and the actual belt speed ratio approaches zero based on each command value. The hydraulic pressure is controlled. The actual belt speed ratio is obtained by dividing the primary rotational speed by the secondary rotational speed.

<Mode switching control>
When the unit transmission ratio is changed across the split transmission ratio, the change of the unit transmission ratio involves switching between the belt mode and the split mode (hereinafter simply referred to as “mode switching”). Mode switching is achieved by switching engagement of the clutches C1 and C2. That is, by controlling the hydraulic pressure supplied to the clutches C1 and C2, the released clutch C1 (engaged side) is engaged, and the engaged clutch C2 (released side) is released, so that the belt mode is released. Switch to split mode. On the contrary, the clutch C1 (release side) in the engaged state is released and the clutch C2 (engagement side) in the released state is engaged, so that the mode is switched from the split mode to the belt mode.

  FIG. 6 shows the secondary rotational speed, output rotational speed, hydraulic pressure supplied to the clutches C1 and C2, engine torque, and belt transmission torque capacity (necessary clamping pressure, marginal clamping pressure) when the mode is switched from the split mode to the belt mode. FIG. 4 is a diagram showing a change over time of transmission torque capacities of clutches C1 and C2.

  In a state in which the unit speed ratio deviates from the split speed ratio, there is a rotational speed difference between the secondary rotational speed and the output rotational speed, that is, there is a differential rotational speed between the secondary shaft 42 (sun gear 71) and the output shaft 32 (ring gear 73). Has occurred.

  Therefore, when the mode is switched, the engagement of the clutches C1 and C2 is switched after the unit gear ratio is shifted to the split gear ratio.

  However, when the accelerator pedal is depressed quickly and greatly due to the driver's acceleration request while the vehicle 1 is traveling in the split mode, and the target gear ratio of the unit gear ratio is set to a value larger than the split gear ratio, The shift response is emphasized, and the engagement of the clutches C1 and C2 is switched for mode switching while the unit transmission ratio does not coincide with the split transmission ratio.

  At this time, the hydraulic pressure supplied to the clutch C1 is lowered by the ECU 101 so that the transmission torque capacity of the release-side clutch C1 is less than the input torque (time T1).

  When the transmission torque capacity of the clutch C1 is less than the input torque, the clutch C1 is in an anti-clutch state, slipping occurs in the clutch C1, and the primary rotational speed and the secondary rotational speed of the continuously variable transmission mechanism 33 are blown up. As a result, the rotational speed difference between the secondary rotational speed and the output rotational speed is reduced.

  When the rotational speed difference between the secondary rotational speed and the output rotational speed is reduced to a predetermined value, the hydraulic pressure (indicated pressure) supplied to the clutch C2 by the ECU 101 is rapidly increased to the fully open pressure (the hydraulic pressure at which the clutch C2 can be completely engaged). Is raised (time T2).

  Before the command pressure of the clutch C2 is increased, the belt clamping pressure of the continuously variable transmission mechanism 33 is increased from the necessary clamping pressure to the marginal clamping pressure. The marginal clamping pressure is a value obtained by adding a margin in consideration of the variation between the command pressure of the hydraulic pressure for engaging the clutch C2 and the actual pressure to the necessary clamping pressure. The necessary clamping pressure is set based on a belt speed ratio obtained by dividing the primary rotational speed by the secondary rotational speed. Specifically, the necessary thrust required for the secondary pulley 44 is required in order to ensure the belt transmission torque according to the input torque and the belt speed ratio. A value obtained by subtracting the thrust by the bias spring and the centrifugal hydraulic thrust applied to the movable sheave 56 according to the secondary rotational speed from the necessary thrust is set as the necessary clamping thrust, and the clamping pressure corresponding to the necessary clamping thrust is necessary. Set as pinching pressure.

<Effect>
As described above, when the mode is switched from the split mode to the belt mode, differential rotation occurs on both sides of the engagement-side clutch C2, that is, the secondary shaft 42 (sun gear 71) and the output shaft 32 (ring gear 73). At this stage, the transmission torque capacity of the release side clutch C1 is lowered. As a result, the clutch C1 enters a half-clutch state, slipping occurs in the clutch C1, the rotation on the continuously variable transmission mechanism 33 side is blown up, and the differential rotation between the secondary shaft 42 and the output shaft 32 is rapidly reduced. Become.

  When the differential rotation between the secondary shaft 42 and the output shaft 32 decreases to a predetermined value, the transmission torque capacity of the clutch C2 is increased. Before the transmission torque capacity of the clutch C2 is increased, the belt clamping pressure of the continuously variable transmission mechanism 33 is increased above the necessary clamping pressure. Thereby, even if the clutch C2 is completely engaged in a state where the differential rotation between the secondary shaft 42 and the output shaft 32 is large, the occurrence of belt slip due to the inertia torque can be suppressed.

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

  For example, the control at the time of switching the mode from the split mode to the belt mode has been taken up. However, the control according to the present invention is performed at the time of switching from the belt mode to the split mode, that is, the clutch C1 in the released state is engaged. The present invention is also applicable when the clutch C2 is released.

  Further, sensors other than the various sensors 111 to 114 shown in FIG. 5 may be connected to the ECU 101, and some of the sensors 111 to 114 may be connected to other ECUs. .

  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 4: Transmission 31: Input shaft 32: Output shaft 33: Continuously variable transmission mechanism 101: ECU (control device, release control means, engagement control means, clamping pressure control means)
C1, C2: Clutch (first engagement element, second engagement element)

Claims (1)

An input shaft, an output shaft, a belt-type continuously variable transmission mechanism for continuously changing power input to the input shaft, and a first path for transmitting power between the continuously variable transmission mechanism and the output shaft And a second engagement element interposed in a second path for transmitting power between the continuously variable transmission mechanism and the output shaft,
The first mode is configured by the engagement of the first engagement element and the release of the second engagement element, and the second mode is configured by the release of the first engagement element and the engagement of the second engagement element. And
In a vehicle equipped with a transmission configured to prevent differential rotation between the first engagement element and the second engagement element when the transmission ratio of the continuously variable transmission mechanism takes a constant value,
A control device for controlling the transmission,
When switching between the first mode and the second mode by switching the engagement between the first engagement element and the second engagement element, the first engagement element or the second engagement on the engagement side is performed. Release control means for lowering the transmission torque capacity of the second engagement element on the release side or the first engagement element in a state where differential rotation occurs in the combined element;
After the transmission torque capacity of the second engagement element or the first engagement element on the disengagement side is lowered, the differential rotation generated in the first engagement element or the second engagement element on the engagement side Engagement control means for increasing the transmission torque capacity of the first engagement element or the second engagement element on the engagement side in response to being reduced to a predetermined value;
At least the first engagement element or the second engagement element on the engagement side from the time point when the differential rotation generated in the first engagement element or the second engagement element on the engagement side is reduced to a predetermined value. And a clamping pressure control means for raising the belt clamping pressure of the continuously variable transmission mechanism to a clamping pressure required in accordance with the transmission gear ratio until the engagement of the continuously variable transmission mechanism.

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