JP2018054080A - Controller of power split type continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller of a power split type continuously variable transmission capable of suppressing occurrence of shift shock in mode switching (switching of two clutches).SOLUTION: In control for a transmission ratio of a power split type continuously variable transmission, switching between a belt mode and a split mode may be needed, and the switching is attained by switching two clutches. When clutch pressure control is in a stable state (S1: YES), skip shift switching is allowed (S2) by switching the two clutches in a state where a belt transmission ratio and a split transmission ratio are different from each other at a constant value or more, and when the clutch pressure control is not in the stable state (S1: NO), the skip shift switching is prohibited (S3).SELECTED DRAWING: Figure 6

Description

  The present invention relates to a power split type non-transmission type mounted on a vehicle together with a power split type continuously variable transmission capable of splitting power input to an input shaft (input shaft) into two systems and transmitting the power to the output shaft (output shaft). The present invention relates to a control device for a step transmission.

  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.

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

  In the belt mode, the sun gear and the ring gear of the planetary gear mechanism are coupled so as to rotate integrally. 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 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, 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.

  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 between a clutch for coupling / separating the sun gear and the ring gear and a clutch for coupling / separating the input shaft and the split drive gear. When the clutch on the engagement side is not differentially rotated, that is, when the gear ratio is changed to a gear ratio that substantially matches the split gear ratio (at or near the split point), the two clutches are switched. The occurrence of shift shock due to mode switching can be suppressed.

  However, it takes time from the start of the gear shift until the unit gear ratio is shifted to the gear ratio corresponding to the target rotational speed. Therefore, when a sudden change in the unit gear ratio across the split gear ratio is required (for example, when the accelerator pedal is depressed quickly and greatly in the split mode), the gear is controlled by controlling the hydraulic pressure (clutch pressure) supplied to the clutch. In a range in which the occurrence of shock can be suppressed, it is desirable to perform so-called jump shift switching, in which the belt mode and the split mode are switched by switching between the two clutches in a state where differential rotation occurs in the clutch.

  However, if the jump shift switching is permitted unconditionally, a shift shock due to the jump shift switching may occur.

  An object of the present invention is to provide a control device for a power split type continuously variable transmission that can suppress the occurrence of a shift shock due to the switching between a first engagement element and a second engagement element.

  In order to achieve the above object, a control device for a power split type continuously variable transmission according to the present invention includes an input shaft, a planetary gear mechanism, an output shaft that rotates integrally with a ring gear of the planetary gear mechanism, and the power of the input shaft. Is a belt-type continuously variable transmission mechanism that shifts gears in a stepless manner and transmits them to the sun gear of the planetary gear mechanism, a split transmission mechanism that shifts the power of the input shaft at a constant gear ratio and transmits it to the carrier of the planetary gear mechanism, and a split shift A first engagement element engaged / released by hydraulic pressure to switch transmission / cut-off of power to / from the carrier by the mechanism, and engagement / release by hydraulic pressure to couple / separate the sun gear and the ring gear so as to be integrally rotatable. A control device used in a power split continuously variable transmission configured to include a second engagement element, for switching between the first engagement element and the second engagement element, A hydraulic control means for controlling the hydraulic pressure supplied to the first engagement element and the second engagement element, and the transmission ratio and split transmission mechanism by the continuously variable transmission mechanism when the hydraulic control by the hydraulic control means is stable; When the jump gear shift switching by switching between the first engagement element and the second engagement element in a state where the constant gear ratio due to is separated by a predetermined distance or more is permitted, and the hydraulic control by the hydraulic control means is not stable Includes jump shift switching permission / denial means for prohibiting jump shift switching.

  According to this configuration, in the state where the first and second engaging elements are respectively released / engaged, the speed ratio (unit speed ratio) of the entire power split continuously variable transmission is a belt type continuously variable transmission mechanism. This corresponds to the transmission ratio (belt transmission ratio). On the other hand, in the state where the first / second engagement elements are engaged / released, the unit transmission ratio decreases as the belt transmission ratio increases, and the unit transmission ratio becomes the belt transmission ratio (a constant transmission ratio by the split transmission mechanism). ) Therefore, in the power split continuously variable transmission, the first and second engaging elements are used interchangeably, so that the speed ratio width of the entire power split continuously variable transmission can be changed to the gear ratio of the continuously variable transmission mechanism alone. It can be secured larger than the width.

  When the first and second engagement elements are switched, the belt transmission ratio is reduced toward a constant transmission ratio (split transmission ratio) by the split transmission mechanism. By switching the first and second engagement elements in a state where the belt speed ratio substantially matches the split speed ratio, occurrence of a speed change shock due to a sudden change in the speed ratio can be suppressed. On the other hand, the time required to make the unit gear ratio coincide with the target gear ratio by performing the jump gear change by switching the first / second engagement elements before the belt gear ratio substantially coincides with the split gear ratio. Can be shortened.

  When the control of the hydraulic pressure (clutch pressure) supplied to the first / second engaging elements is stable, jump shift switching is permitted. In this state, since the clutch pressure can be controlled as intended, it is possible to suppress the occurrence of a shift shock due to jump shift switching by controlling the clutch pressure. Therefore, when a sudden change in the unit gear ratio is required, the unit gear ratio can be quickly matched with the target gear ratio by performing the jump gear shift switching.

  However, if the clutch pressure control is not stable, the clutch pressure cannot be controlled as intended. Therefore, there is a concern that the clutch pressure control cannot suppress the occurrence of a shift shock due to the jump shift switching. There is. Therefore, jump shift switching is prohibited when the clutch pressure control is not stable. Thereby, generation | occurrence | production of the transmission shock by switching of the 1st / 2nd engagement element can be suppressed.

  Note that the state in which the hydraulic control by the hydraulic control means is not stable is the initial learning (for example, the machine difference information that is implemented before the vehicle equipped with the power split type continuously variable transmission is shipped to the controller) Learning, the initial several times of learning performed during traveling of a vehicle equipped with a power split continuously variable transmission) is not completed, and the oil temperature of the power split continuously variable transmission is below a predetermined temperature Examples include a state and a state where a failure has occurred.

  In a state where a failure has occurred, the switching of the first and second engaging elements is generally prohibited, but the jump gear change is prohibited and the belt gear ratio substantially matches the split gear ratio. By allowing the first / second engagement elements to be switched in the state, the first / second engagement elements can be switched in a state where a failure has occurred.

  According to the present invention, it is possible to suppress the occurrence of a shift shock due to the switching between the first engagement element and the second engagement element, and to perform the power split by switching the jump shift within a range in which the generation of the shift shock can be suppressed. It is possible to quickly match the speed ratio of the entire type continuously variable transmission with the target speed ratio.

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 each engagement element at the time of advance of a vehicle, and reverse drive. It is a collinear diagram which shows the relationship of the rotation speed (rotation speed) of the sun gear of a planetary gear mechanism, a carrier, and a ring gear. It is a figure which shows the relationship between a belt gear ratio and a unit gear ratio. It is a flowchart which shows the flow of the process at the time of mode switching.

  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 the torque converter 3 and the power split type continuously variable transmission 4.

  The vehicle 1 includes an ECU (Electronic Control Unit) 11 having a configuration including a microcomputer (microcontroller unit). The microcomputer incorporates, for example, a CPU, ROM, RAM, data flash (flash memory), and the like. Although FIG. 1 shows only one ECU 11 for controlling the power split type continuously variable transmission 4, the vehicle 1 includes a plurality of ECUs having the same configuration as the ECU 11 in order to control each part. Is installed. A plurality of ECUs including the ECU 11 are connected so as to be capable of bidirectional communication by a CAN (Controller Area Network) communication protocol.

  The ECU 11 is connected to a turbine rotational speed sensor 12, a primary rotational speed sensor 13, a secondary rotational speed sensor 14, an oil temperature sensor 15, and the like.

  The turbine speed sensor 12 outputs a pulse signal synchronized with the rotation of the turbine runner of the torque converter 3 as a detection signal. The ECU 11 converts the frequency of the pulse signal input from the turbine rotation speed sensor 12 into a turbine rotation speed that is the rotation speed of the turbine runner.

  The primary rotational speed sensor 13 outputs, for example, a pulse signal synchronized with the rotation of the primary shaft 51 (see FIG. 2) of the power split continuously variable transmission 4 as a detection signal. The ECU 11 converts the frequency of the pulse signal input from the primary rotational speed sensor 13 into the rotational speed (primary rotational speed) of the primary shaft 51.

  For example, the secondary rotational speed sensor 14 outputs a pulse signal synchronized with the rotation of the secondary shaft 52 (see FIG. 2) of the power split continuously variable transmission 4 as a detection signal. The ECU 11 converts the frequency of the pulse signal input from the secondary rotational speed sensor 14 into the rotational speed (secondary rotational speed) of the secondary shaft 52.

  The oil temperature sensor 15 outputs a detection signal corresponding to the temperature of the oil (fluid) enclosed in the power split type continuously variable transmission 4. The ECU 11 acquires the oil temperature (oil temperature) from the detection signal of the oil temperature sensor 15.

  The ECU 11 supplies a hydraulic circuit 16 for supplying hydraulic pressure to each part of the power split continuously variable transmission 4 based on information acquired from detection signals of various sensors and / or various information input from other ECUs. The gear ratio of the power split type continuously variable transmission 4 is controlled by controlling various valves provided.

  In the control of the gear ratio, for example, a shift diagram that defines the relationship between the accelerator opening (the amount of depression of the accelerator pedal), the vehicle speed, and the target rotational speed is used. The shift diagram is stored in the form of a map in a nonvolatile memory (for example, ROM) of the ECU 11. Information on the accelerator opening and the vehicle speed may be input to the ECU 11 from another ECU, or an accelerator sensor that outputs a detection signal according to the operation amount of the accelerator pedal and a vehicle speed sensor that outputs a detection signal according to the vehicle speed. It may be connected to ECU11 and acquired from those detection signals. The ECU 11 sets a target rotational speed corresponding to the accelerator opening and the vehicle speed based on the shift map, and the rotational speed (turbine rotational speed) input to the power split type continuously variable transmission 4 matches the target rotational speed. Thus, the gear ratio of the power split type continuously variable transmission 4 is changed to a target gear ratio (target gear ratio).

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

  The engine 2 includes 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. An E / G output shaft 21 is connected to the pump impeller 31, and the pump impeller 31 is provided so as to be integrally rotatable about the same rotation axis as the E / G output shaft 21. 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 21 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 21.

  In a state where the lockup clutch 33 is 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 are rotated together.

  The power split type continuously variable transmission 4 transmits the power input from the torque converter 3 to the 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 reverse gear mechanism 44, a planetary gear mechanism 45, a split drive gear 46 and a split driven gear 47.

  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 48 is supported on the output shaft 42 so as not to be relatively rotatable. The output gear 48 meshes with the differential gear 6 (the input gear of the differential gear 6).

  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. (Primary sheave) 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 hydraulic chamber 64 is formed between the movable sheave 62 and the cylinder 63.

  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. (Secondary sheave) 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 hydraulic chamber 68 is formed between the movable sheave 66 and the cylinder 67. In the rotational axis direction, the positional relationship between the fixed sheave 65 and the movable sheave 66 is reversed from the positional relationship between the fixed sheave 61 and the movable sheave 62 of the primary pulley 53.

  In the continuously variable transmission mechanism 43, the hydraulic pressure supplied to the hydraulic 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, so that the primary The pulley ratio between the pulley 53 and the secondary pulley 54 is continuously changed steplessly.

  Specifically, when the pulley ratio is decreased, the hydraulic pressure supplied to the hydraulic 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.

  When the pulley ratio is increased, the hydraulic pressure supplied to the hydraulic chamber 64 of the primary pulley 53 is reduced. 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.

  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 supplied to the hydraulic chamber 68 of the secondary pulley 54 is controlled so that a thrust according to the magnitude of the torque input to the input shaft 41 is obtained.

  The reverse gear mechanism 44 is configured to transmit the power input to the input shaft 41 to the primary shaft 51 by reversely rotating and decelerating. Specifically, the reverse gear mechanism 44 has an input shaft gear 71 supported on the input shaft 41 so as not to rotate relative to the input shaft 41, and has a larger diameter and a larger number of teeth than the input shaft gear 71. A primary shaft gear 72 that is supported so as to be movable in the direction of the rotation axis and is not relatively rotatable, and meshes with the input shaft gear 71.

  The planetary gear mechanism 45 includes a sun gear 81, a carrier 82, and a ring gear 83. The sun gear 81 is supported by the secondary shaft 52 so as to be movable in the rotational axis direction and not relatively rotatable by spline fitting. The carrier 82 is fitted on the output shaft 42 so as to be relatively rotatable. The carrier 82 rotatably supports a plurality of pinion gears 84. The plurality of pinion gears 84 are arranged on the circumference and mesh with the sun gear 81. The ring gear 83 has an annular shape that collectively surrounds the plurality of pinion gears 84, and meshes with the pinion gears 84 from the outside in the rotational radial direction of the secondary shaft 52. An output shaft 42 is connected to the ring gear 83, and the ring gear 83 is provided so as to be integrally rotatable about the same rotation axis as the output shaft 42.

  The split drive gear 46 is fitted on the input shaft 41 so as to be relatively rotatable.

  The split driven gear 47 is provided so as to be integrally rotatable about the same rotation axis as the carrier 82 of the planetary gear mechanism 45. The split driven gear 47 is formed with a smaller diameter than the split drive gear 46 and has fewer teeth than the split drive gear 46.

  The power split type continuously variable 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 41 and the split drive gear 46 are directly coupled (coupled so as to be integrally rotatable) and a released state in which the direct coupling is released.

  The clutch C2 is switched between an engaged state in which the sun gear 81 and the ring gear 83 of the planetary gear mechanism 45 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 82 of the planetary gear mechanism 45 is braked and a release state in which the rotation of the carrier 82 is allowed.

<Transmission mode>
FIG. 3 is a diagram illustrating states of the clutches C1 and C2 and the brake B1 when the vehicle 1 moves forward and backward. FIG. 4 is a collinear diagram showing the relationship between the rotational speeds (rotational speeds) of the sun gear 81, the carrier 82, and the ring gear 83 of the planetary gear mechanism 45. FIG. 5 is a diagram showing the relationship between the belt transmission ratio, which is the transmission ratio by the continuously variable transmission mechanism 43, and the unit transmission ratio, which is the overall transmission ratio of the power split type continuously variable transmission 4.

  In FIG. 3, “◯” 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 power split type continuously variable transmission 4 has a belt mode and a split mode as shift modes when the vehicle 1 moves forward. The belt mode and the split mode are switched by changing clutches C1 and C2.

  In the belt mode, as shown in FIG. 3, the clutch C1 and the brake B1 are released, and the clutch C2 is engaged. As a result, the split drive gear 46 is disconnected from the input shaft 41, the carrier 82 of the planetary gear mechanism 45 becomes free (free rotation state), and the sun gear 81 and the ring gear 83 of the planetary gear mechanism 45 are directly connected.

  The power input to the input shaft 41 is reversed and decelerated by the reverse gear mechanism 44 and 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 sun gear 81 and the ring gear 83 of the planetary gear mechanism 45 are directly connected, the sun gear 81, the ring gear 83, and the output shaft 42 rotate together with the secondary shaft 52. Therefore, in the belt mode, as shown in FIGS. 4 and 5, the unit gear ratio matches the belt gear ratio, that is, the pulley ratio between the primary pulley 53 and the secondary pulley 54 of the continuously variable transmission mechanism 43.

  In the split mode, as shown in FIG. 3, the clutch C1 is engaged, and the clutch C2 and the brake B1 are released. Thereby, the input shaft 41 and the split drive gear 46 are directly connected, the carrier 82 of the planetary gear mechanism 45 becomes free, and the sun gear 81 and the ring gear 83 of the planetary gear mechanism 45 are disconnected.

  The power input to the input shaft 41 is reversed and decelerated by the reverse gear mechanism 44 and transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43, and is transmitted from the primary shaft 51 via the primary pulley 53, the belt 55 and the secondary pulley 54. Is transmitted to the secondary shaft 52 and transmitted to the sun gear 81 of the planetary gear mechanism 45. On the other hand, the power input to the input shaft 41 is accelerated and transmitted from the split drive gear 46 to the carrier 82 of the planetary gear mechanism 45 through the split driven gear 47.

  Since the gear ratio (split gear ratio) between the split drive gear 46 and the split driven gear 47 is constant and unchanged (fixed), the planetary gear mechanism 45 can be used in the split mode if the power input to the input shaft 41 is constant. The rotation of the carrier 82 is maintained at a constant speed. For this reason, when the pulley ratio is increased, the rotational speed of the sun gear 81 of the planetary gear mechanism 45 decreases, so that the rotational speed of the ring gear 83 (output shaft 42) of the planetary gear mechanism 45 is reduced as shown by the broken line in FIG. Go up. As a result, in the split mode, as shown in FIG. 5, the larger the pulley ratio of the continuously variable transmission mechanism 43, the smaller the unit transmission ratio of the power split type continuously variable transmission 4.

  The rotation of the output shaft 42 in the belt mode and the split mode is transmitted to the differential gear 6 via the output gear 48. Thereby, the drive shafts 7 and 8 of the vehicle 1 rotate in the forward direction.

  In the reverse mode during reverse travel of the vehicle 1, as shown in FIG. 3, the clutches C1 and C2 are released and the brake B1 is engaged. Thereby, the split drive gear 46 is disconnected from the input shaft 41, the sun gear 81 and the ring gear 83 of the planetary gear mechanism 45 are disconnected, and the carrier 82 of the planetary gear mechanism 45 is braked.

  The power input to the input shaft 41 is reversed and decelerated by the reverse gear mechanism 44 and transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43, and is transmitted from the primary shaft 51 via the primary pulley 53, the belt 55 and the secondary pulley 54. Then, the sun gear 81 of the planetary gear mechanism 45 is rotated integrally with the secondary shaft 52. Since the carrier 82 of the planetary gear mechanism 45 is braked, when the sun gear 81 rotates, the ring gear 83 of the planetary gear mechanism 45 rotates in the opposite direction to the sun gear 81. The rotation direction of the ring gear 83 is opposite to the rotation direction of the ring gear 83 during forward movement (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 differential gear 6 via the output gear 48. Thereby, the drive shafts 7 and 8 of the vehicle 1 rotate in the reverse direction.

<Processing during mode switching>
FIG. 6 is a flowchart showing the flow of processing at the time of mode switching.

  In the control of the gear ratio of the power split type continuously variable transmission 4, there is a case where switching between the belt mode and the split mode (hereinafter simply referred to as “mode switching”) is required. Mode switching is achieved by changing clutches C1 and C2. That is, by the control of the hydraulic pressure supplied to the clutches C1 and C2 (hereinafter referred to as “clutch pressure control”), the released clutch C1 (engaged side) is engaged, and the engaged clutch C2 (released side). ) Is released, the belt mode is switched to the 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.

  When the mode is switched (clutch C1, C2 is switched), the ECU 11 reduces the belt speed ratio toward the split speed ratio that is the gear ratio between the split drive gear 46 and the split driven gear 47. Then, the mode switching process shown in FIG. 6 is executed.

  In the mode switching process, when the clutch pressure control is stable (YES in step S1), the mode switching is performed by switching the clutches C1 and C2 in a state where the belt speed ratio and the split speed ratio are separated from each other by a certain distance. If the shift switching is permitted (step S2) and the clutch pressure control is not stable (NO in step S1), the jump shift switching is prohibited (step S3).

  The state where the clutch pressure control is not stable refers to a state where at least one of the following (1) to (3) is satisfied, for example.

(1) Initial learning (for example, learning by writing in the ECU 11 machine difference information that is implemented before the vehicle 1 equipped with the power split continuously variable transmission 4 is shipped, The initial learning for several times during the traveling of the mounted vehicle 1) is incomplete.
(2) The oil temperature of the power split type continuously variable transmission 4 is equal to or lower than a predetermined temperature.
(3) The power split type continuously variable transmission 4 has failed.

  When the clutch pressure control is stable, the belt speed ratio is reduced to a speed ratio that can be suppressed by the clutch pressure control before the belt speed ratio coincides with the split speed ratio and the belt speed ratio can be controlled by clutch pressure control. At that time, even if the belt speed ratio is more than a certain distance from the split speed ratio, clutch pressure control for changing clutches C1 and C2 is executed. As a result, the jump gear change is performed, so that the time required to make the unit gear ratio coincide with the target gear ratio can be shortened.

  On the other hand, when the clutch pressure control is not stable, the jump shift switching is prohibited, so that the clutches C1 and C2 are not switched until the difference between the belt gear ratio and the split gear ratio becomes smaller than a certain value. Then, clutch speed control for changing over the clutches C1 and C2 is executed at the time when the gear ratio is changed to a speed ratio that substantially matches the split speed ratio (at or near the split point). Thereby, the occurrence of a shift shock due to mode switching can be suppressed.

  The state where the belt speed ratio and the split speed ratio are separated by a certain amount or more is equivalent to a state where a differential rotation of a certain value or more is generated in the clutches C1 and C2 before engagement. Changing the clutches C1 and C2 in a state where the distance is more than a certain distance is the same as changing the clutches C1 and C2 in a state where a differential rotation of a certain level or more has occurred in the clutches C1 and C2 before engagement.

  Accordingly, when the clutch pressure control is not stable in the mode switching process described above, the clutches C1 and C2 are switched when the differential rotation of a certain level or more is generated between the input shaft 41 and the split drive gear 46. Is not allowed to switch from belt mode to split mode (jumping gear shifting switching), and the clutch is in a state where differential rotation more than a certain level occurs between the sun gear 81 of the planetary gear mechanism 45 and the carrier 82 (ring gear 83). Mode switching (jumping gear shifting switching) from the split mode to the belt mode by switching between C1 and C2 is prohibited.

<Effect>
As described above, when the clutch pressure control is stable, jump shift switching is permitted. Therefore, when sudden change of the unit gear ratio is required, the unit gear ratio is targeted by performing jump shift switching. Can be quickly matched with the gear ratio.

  On the other hand, when the clutch pressure control is not stable, jump shift switching is prohibited, so that occurrence of a shift shock due to mode switching can be suppressed.

<Modification>
Although the embodiment of the present invention has been described above, the present invention can be implemented in other forms, and various modifications can be made to the above-described configuration within the scope of the matters described in the claims. It is possible to apply.

4: Power split type continuously variable transmission 11: ECU (hydraulic control means, jump speed change permission / rejection means, control device)
41: input shaft 42: output shaft 43: continuously variable transmission mechanism 45: planetary gear mechanism 46: split drive gear (split transmission mechanism)
47: Split driven gear (split transmission mechanism)
81: Sun gear 82: Carrier 83: Ring gear C1: Clutch (first engaging element)
C2: Clutch (second engagement element)

Claims (1)

An input shaft, a planetary gear mechanism, an output shaft that rotates integrally with the ring gear of the planetary gear mechanism, and a belt-type continuously variable transmission that continuously transmits the power of the input shaft to the sun gear of the planetary gear mechanism. A mechanism, a split speed change mechanism that changes the power of the input shaft at a fixed speed ratio and transmits the power to the carrier of the planetary gear mechanism, and a hydraulic pressure mechanism that switches between transmission / cutoff of power to the carrier by the split speed change mechanism. A power split type non-rotating configuration including a first engagement element to be engaged / released, and a second engagement element to be engaged / released by hydraulic pressure so as to connect / disconnect the sun gear and the ring gear so as to be integrally rotatable. A control device used for a step transmission,
Hydraulic control means for controlling the hydraulic pressure supplied to the first engagement element and the second engagement element for switching between the first engagement element and the second engagement element;
When the control of the hydraulic pressure by the hydraulic control means is stable, the first engagement in a state in which the transmission ratio by the continuously variable transmission mechanism and the constant transmission ratio by the split transmission mechanism are separated by a predetermined distance or more. A jump shift switching permission / rejection means for permitting jump shift switching by switching between an element and the second engagement element and prohibiting the jump shift switching when the hydraulic control by the hydraulic control means is not stable; Including the control device.

Images