JP2016089894A - Control device of power split-type continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of a power split-type continuously variable transmission capable of controlling a pulley ratio and smoothly switching from a split mode to a belt mode even when secondary rotating speed detecting means is failed.SOLUTION: In a power split-type continuously variable transmission including a continuously variable transmission mechanism having a constitution similar as a belt-type continuously variable transmission, and a planetary gear mechanism for composing the power through a constant transmission mechanism having a constant transmission ratio and the continuously variable transmission mechanism, and the power through the constant transmission mechanism, when a secondary rotating speed sensor for detecting a rotating speed (secondary rotating speed) of a secondary shaft of the continuously variable transmission mechanism is failed, the secondary rotating speed Nis calculated by using a rotating speed Nof a primary shaft, a rotating speed Nof an output shaft of a power split type continuously variable transmission, a transmission ratio γ, and tooth numbers Z, Zof a sun gear and a ring gear of the planetary gear mechanism.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a control device for a power split type continuously variable 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 the proposal includes a continuously variable transmission mechanism that continuously changes power by changing a transmission ratio, a constant transmission mechanism that changes power at a constant transmission ratio, and a continuously variable transmission mechanism. And a synthesizing gear mechanism including a planetary gear mechanism for synthesizing the power passing through the power and the power passing through the constant speed change mechanism. A secondary shaft of a continuously variable transmission mechanism is connected to the sun gear of the synthesizing gear mechanism. An output shaft is connected to the ring gear of the synthesizing 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.

  This power split type continuously variable transmission has, as a power transmission mode (transmission mode), a belt mode in which power is transmitted to the synthesizing gear mechanism only through the continuously variable transmission mechanism, and the power is continuously variable and constant. A split mode transmitted to the synthesizing gear mechanism via the speed change mechanism.

  In the belt mode, the sun gear and the ring gear of the synthesizing gear mechanism are directly connected by the clutch, and the carrier of the synthesizing gear mechanism is brought into a free 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 of the power split continuously variable transmission matches the gear ratio of the continuously variable transmission mechanism.

  In the split mode, the direct coupling between the sun gear and the ring gear of the synthesizing gear mechanism is released, and the power passing through the constant speed change mechanism is input to the carrier of the synthesizing gear mechanism. Since the speed ratio of the constant speed change 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 kept constant. Therefore, when the gear ratio of the continuously variable transmission mechanism is increased and the rotational speed of the sun gear is decreased, the rotational speed of the output gear connected to the ring gear and the ring gear increases, and the gear ratio of the power split continuously variable transmission decreases. . Therefore, in the split mode, the gear ratio of the power split type continuously variable transmission is equal to or less than the constant gear ratio (the gear ratio of the constant transmission mechanism).

  In both the belt mode and the split mode, the gear ratio of the power split type continuously variable transmission is controlled by controlling the gear ratio of the continuously variable transmission mechanism. Therefore, the power split type continuously variable transmission includes a primary rotational speed sensor that detects the rotational speed of the primary shaft (primary pulley) and a secondary rotational speed sensor that detects the rotational speed of the secondary shaft (secondary pulley). ing. Then, in order to control the transmission ratio of the continuously variable transmission mechanism, the current transmission ratio (pulley ratio) of the continuously variable transmission mechanism is calculated based on each rotational speed detected by the primary rotational speed sensor and the secondary rotational speed. .

  Further, in the split mode, when the gear ratio of the continuously variable transmission mechanism is larger than the gear ratio of the constant transmission mechanism, the gear ratio of the power split continuously variable transmission and the gear ratio of the continuously variable transmission mechanism do not match. When the clutch is engaged and the mode is switched from the split mode to the belt mode with a large difference between the gear ratios, the gear ratio of the power split type continuously variable transmission greatly increases and the engine speed exceeds the rev limit. There is a risk of sudden deceleration of the vehicle due to overrev or powerful engine braking. Therefore, the power split type continuously variable transmission is further provided with an output rotational speed sensor for detecting the rotational speed of the output shaft, and the secondary rotational speed sensor and the output rotational speed sensor are used for switching from the split mode to the belt mode. Is performed in a state in which the respective rotation speeds detected substantially coincide with each other (a state in which the gear ratio of the power split continuously variable transmission and the gear ratio of the continuously variable transmission mechanism substantially coincide).

  However, when the secondary rotational speed sensor fails, the rotational speed of the secondary shaft becomes unknown, so the control of the gear ratio of the power split type continuously variable transmission and the good switching from the split mode to the belt mode (overlev and Switching which does not cause sudden deceleration of the vehicle becomes difficult or impossible.

  An object of the present invention is to provide a control device for a power split type continuously variable transmission capable of controlling the pulley ratio and satisfactorily switching from the split mode to the belt mode even when the secondary rotational speed detecting means fails. It is to be.

  In order to achieve the above object, a power split type continuously variable transmission control device according to the present invention is provided in parallel with an input shaft, an output shaft, a primary shaft coupled to the input shaft, and the primary shaft. A secondary shaft, a primary pulley supported by the primary shaft, a secondary pulley supported by the secondary shaft, a belt wound around the primary pulley and the secondary pulley, a carrier that rotatably supports the pinion gear, and a pinion gear, A constant gear for meshing the sun gear coupled with the secondary shaft, the ring gear meshing with the pinion gear, coupled with the output shaft, and shifting the power input to the input shaft at a constant gear ratio and transmitting it to the carrier A belt mode in which the sun gear and the ring gear are directly connected when the carrier is in a freely rotating state, and the sun gear and the ring gear. A control device for controlling a power split type continuously variable transmission configured to be switched to a split mode in which direct connection is released and power passing through a constant speed change mechanism is transmitted to a carrier. When the primary rotational speed detecting means for detecting, the secondary rotational speed detecting means for detecting the rotational speed of the secondary shaft, the output rotational speed detecting means for detecting the rotational speed of the output shaft, and the secondary rotational speed detecting means fail, Calculate the rotation speed of the secondary shaft based on the rotation speed detected by the primary rotation speed detection means, the rotation speed detected by the output rotation speed detection means, the gear ratio of the constant transmission mechanism, and the number of teeth of the sun gear and ring gear. Rotating speed calculation means.

According to this configuration, when the secondary rotational speed detection means fails, the rotational speed detected by the primary rotational speed detection means, the rotational speed detected by the output rotational speed detection means, the gear ratio of the constant speed change mechanism, The rotational speed of the secondary shaft is calculated based on the number of teeth of the sun gear and the ring gear. Specifically, the rotation speed of the primary shaft is N _pri , the rotation speed of the output shaft is N _out , the gear ratio of the constant transmission mechanism is γ _g, and the number of teeth of the sun gear and the ring gear is Z _s and Z _r , respectively. As a result, the rotational speed N _sec of the secondary shaft is calculated according to the following equation.

_{N sec = N pri (1 /} γ g -N pri / N out) · Z r / Z s + N pri / γ g

  Even if the secondary rotational speed detection means breaks down, the rotational speed of the secondary shaft is calculated, so the pulley ratio between the primary pulley and the secondary pulley can be calculated. Therefore, it is possible to control the speed ratio of the power split type continuously variable transmission by controlling the pulley ratio and to satisfactorily switch from the split mode to the belt mode.

  Since the input shaft is connected to the primary shaft, detecting the rotational speed of the primary shaft is equivalent to detecting the rotational speed of the input shaft. Therefore, the primary rotational speed detection means can be rephrased as input rotational speed detection means for detecting the rotational speed of the input shaft.

  Since the secondary shaft is connected to the sun gear, detecting the rotational speed of the secondary shaft is equivalent to detecting the rotational speed of the sun gear. Therefore, the secondary rotational speed detection means can be rephrased as sun gear rotational speed detection means for detecting the rotational speed of the sun gear.

  Since the output shaft is connected to the ring gear, detecting the rotational speed of the output shaft is equivalent to detecting the rotational speed of the ring gear. Therefore, the output rotational speed detection means can be restated as a ring gear rotational speed detection means for detecting the rotational speed of the ring gear.

  If a failure occurs in the secondary rotational speed detection means or the output rotational speed detection means, the differential rotational speed between the secondary shaft and the output shaft cannot be detected, and even if the differential rotational speed can be calculated, the calculated value is accurate. Therefore, it is preferable that the power transmission mode (shift mode) is fixed to one of the belt mode and the split mode.

  In the split mode, the speed ratio of the power split continuously variable transmission is limited to a certain speed ratio or less, whereas in the belt mode, the speed ratio width of the continuously variable transmission mechanism is set to the speed ratio of the power split continuously variable transmission. It can be secured as a width. Therefore, it is more preferable that the power transmission mode is fixed to the belt mode when a failure occurs in the secondary rotation speed detection means or the output rotation speed detection means. In other words, when the secondary rotation speed detection means or the output rotation speed detection means has failed, in the belt mode, switching from the belt mode to the split mode is prohibited, and in the split mode, More preferably, after switching from the split mode to the belt mode, switching from the belt mode to the split mode is prohibited.

  In addition, when a failure occurs in the secondary rotation speed detection means or the output rotation speed detection means in the split mode, if the mode is immediately switched from the split mode to the belt mode, the gear ratio of the power split continuously variable transmission is greatly increased. There is a risk that the vehicle will suddenly decelerate due to overrev exceeding the rev limit or strong engine brake. Therefore, when one of the secondary rotational speed detection means or the output rotational speed detection means fails in the split mode, the pulley ratio between the primary pulley and the secondary pulley is changed to a predetermined switching gear ratio, and then the belt is switched from the split mode to the belt. More preferably, the mode can be switched.

  In other words, the control device for the power split continuously variable transmission changes the pulley ratio between the primary pulley and the secondary pulley to a predetermined switching speed when one of the secondary rotational speed detection means or the output rotational speed detection means fails in the split mode. The mode switch that prohibits switching from the belt mode to the split mode when one of the mode switching means that switches from the split mode to the belt mode and the secondary rotational speed detection means or the output rotational speed detection means fails. It is preferable to further include prohibition means.

  When the secondary rotational speed detection means fails in the split mode, the rotational speed of the secondary shaft is calculated, and the primary pulley and the secondary are detected using the calculated rotational speed and the rotational speed detected by the primary rotational speed detection means. After the pulley ratio with the pulley is calculated and the calculated pulley ratio is changed to the switching gear ratio, the split mode is preferably switched to the belt mode.

  That is, the control device for the power split type continuously variable transmission, when the secondary rotational speed detecting means fails in the split mode, determines the rotational speed detected by the primary rotational speed detecting means and the rotational speed calculated by the rotational speed calculating means. The mode switching means further changes the pulley ratio calculated by the pulley ratio calculating means up to the switching gear ratio when the secondary rotation speed detecting means fails in the split mode. It is better to switch from the split mode to the belt mode later.

  Further, the control device for the power split type continuously variable transmission includes a rotation speed detected by the primary rotation speed detection means and a rotation detected by the output rotation speed detection means in the belt mode when the secondary rotation speed detection means fails. Second pulley ratio calculation means for calculating the pulley ratio using a number may be further included.

  According to the present invention, even if the secondary rotational speed detection means fails, the rotational speed of the secondary shaft is calculated, so that the pulley ratio between the primary pulley and the secondary pulley can be calculated. Therefore, it is possible to control the transmission ratio of the power split type continuously variable transmission by controlling the pulley ratio and to satisfactorily switch from the split mode to the belt mode.

It is a skeleton figure which shows the structure of the drive system of the vehicle to which the control apparatus which concerns on one Embodiment of this invention is applied. It is a figure which shows the state of the high brake, reverse brake, and low clutch at the time of advance of a vehicle, and reverse drive. It is a figure which shows the relationship between the gear ratio (belt gear ratio) of a continuously variable transmission mechanism, and the gear ratio (T / M gear ratio) of a power division type continuously variable transmission. It is a collinear diagram which shows the relationship of the rotation speed of the sun gear of a synthetic | combination gear mechanism, a carrier, and a ring gear. It is a block diagram which shows the principal part of the electrical structure of a vehicle. It is a flowchart which shows the flow of a sensor failure process. It is a figure for demonstrating the type | formula which calculates a secondary rotation speed.

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

<Configuration of drive system>

  FIG. 1 is a skeleton diagram showing a configuration of a drive system of a vehicle 1 to which a control device according to an embodiment of the present invention is applied.

  The vehicle 1 is an automobile that uses an engine (E / G) 2 as a power source. The vehicle 1 is equipped with a torque converter 3 and a power split type continuously variable transmission 4.

  The torque converter 3 includes a torque converter input shaft 11, a torque converter output shaft 12, a pump impeller 13, a turbine runner 14, and a lockup clutch 15. The torque converter input shaft 11 and the torque converter output shaft 12 are provided so as to be rotatable about the same rotational axis as the output shaft 16 of the engine 2 (hereinafter referred to as “E / G output shaft 16”). An E / G output shaft 16 is connected to the torque converter input shaft 11. A torque converter input shaft 11 is connected to the center of the pump impeller 13, and the pump impeller 13 is provided to be rotatable integrally with the torque converter input shaft 11. The torque converter output shaft 12 is connected to the center of the turbine runner 14, and the turbine runner 14 is provided to be rotatable integrally with the torque converter output shaft 12. When the lockup clutch 15 is engaged, the pump impeller 13 and the turbine runner 14 are directly connected, and when the lockup clutch 15 is released, the pump impeller 13 and the turbine runner 14 are separated.

  When power is input from the E / G output shaft 16 to the torque converter input shaft 11 in a state where the lockup clutch 15 is released, the torque converter input shaft 11 and the pump impeller 13 rotate. When the pump impeller 13 rotates, an oil flow from the pump impeller 13 toward the turbine runner 14 is generated. This oil flow is received by the turbine runner 14 and the turbine runner 14 rotates. At this time, the amplifying action of the torque converter 3 occurs, and the turbine runner 14 generates a power larger than the power (torque) input to the torque converter input shaft 11. The power of the turbine runner 14 is output from the torque converter output shaft 12.

  In a state where the lock-up clutch 15 is engaged, when power is input from the E / G output shaft 16 to the torque converter input shaft 11, the torque converter input shaft 11, the pump impeller 13, and the turbine runner 14 rotate together. . The power generated by the rotation of the turbine runner 14 is output from the torque converter output shaft 12.

  The power split type continuously variable transmission 4 transmits the power output from the torque converter 3 to the differential gear 5. The power split type continuously variable transmission 4 includes a T / M input shaft 21, a T / M output shaft 22, a continuously variable transmission mechanism 23, a constant transmission mechanism 24, and a synthesizing gear mechanism 25.

  The torque converter output shaft 12 is connected to the T / M input shaft 21.

  The T / M output shaft 22 is provided in parallel with the T / M input shaft 21.

  The continuously variable transmission mechanism 23 has the same configuration as a known belt-type continuously variable transmission (CVT). Specifically, the continuously variable transmission mechanism 23 is supported by the primary shaft 31 connected to the T / M input shaft 21, the secondary shaft 32 provided in parallel with the primary shaft 31, and the primary shaft 31 so as not to be relatively rotatable. A primary pulley 33, a secondary pulley 34 supported by the secondary shaft 32 so as not to rotate relatively, and a belt 35 wound around the primary pulley 33 and the secondary pulley 34.

  The constant speed change mechanism 24 includes a planetary gear mechanism 41, a split drive gear 42, a split driven gear 43, and an idle gear 44.

  The planetary gear mechanism 41 includes a carrier 45, a sun gear 46, and a ring gear 47. The carrier 45 is supported by the T / M input shaft 21 so as not to be relatively rotatable. The carrier 45 supports a plurality of pinion gears 48 so as to be rotatable. The plurality of pinion gears 48 are arranged at equiangular intervals on the circumference. The sun gear 46 is externally fitted to the T / M input shaft 21 so as to be relatively rotatable, and meshes with each pinion gear 48 from the inside in the rotational radial direction of the T / M input shaft 21. The ring gear 47 has an annular shape surrounding the carrier 45, and meshes with each pinion gear 48 from the outside in the rotational radial direction of the T / M input shaft 21.

  The split drive gear 42 is provided so as to be able to rotate integrally with the sun gear 46.

  The split driven gear 43 is provided on the outer periphery of the carrier 51 of the synthesizing gear mechanism 25 described below so as to be able to rotate integrally with the carrier 51.

  The idle gear 44 meshes with the split drive gear 42 and the split driven gear 43.

  The synthesizing gear mechanism 25 has a configuration of a planetary gear mechanism. That is, the synthesizing gear mechanism 25 includes a carrier 51, a sun gear 52, and a ring gear 53. The secondary shaft 32 of the continuously variable transmission mechanism 23 is inserted into the center of the carrier 51 so as to be relatively rotatable. The carrier 51 rotatably supports a plurality of pinion gears 54. The plurality of pinion gears 54 are arranged at equal angular intervals on the circumference. The sun gear 52 is supported by the secondary shaft 32 so as not to be relatively rotatable, and meshes with each pinion gear 54 from the inner side in the rotational radial direction of the secondary shaft 32. The ring gear 53 has an annular shape that surrounds the periphery of the carrier 51, and meshes with each pinion gear 54 from the outside in the rotational radial direction of the secondary shaft 32. One end of the T / M output shaft 22 is connected to the center of the ring gear 53, and the ring gear 53 is provided so as to be able to rotate integrally with the T / M output shaft 22. An output gear 55 is supported at the other end of the T / M output shaft 22 so as not to be relatively rotatable.

  The rotation of the output gear 55 is transmitted to the differential gear 5 via the idle gear mechanism 6. The idle gear mechanism 6 includes an idle shaft 61 provided in parallel with the T / M output shaft 22, and a first idle gear 62 and a second idle gear 63 that are supported by the idle shaft 61 so as not to rotate relative to each other. . The first idle gear 62 meshes with the output gear 55. The second idle gear 63 meshes with a ring gear 64 provided in the differential gear 5.

  The power split type continuously variable transmission 4 includes a high brake HB, a reverse brake RB, and a low clutch LC.

  The high brake HB is switched between an engaged state (on) in which the ring gear 47 is braked and a released state (off) in which the ring gear 47 is allowed to rotate.

  The reverse brake RB is switched between an engaged state (on) in which the split drive gear 42 (sun gear 46) is braked and a released state (off) in which the split drive gear 42 is allowed to rotate.

  The low clutch LC is switched between an engaged state (ON) in which the T / M output shaft 22 and the secondary shaft 32 are directly connected, and a released state (OFF) in which the direct connection is released.

<Power transmission mode>

  FIG. 2 is a diagram illustrating states of the high brake HB, the reverse brake RB, and the low clutch LC when the vehicle 1 is moving forward and backward. FIG. 3 shows the relationship between the speed ratio of the continuously variable transmission mechanism 23 (hereinafter referred to as “belt speed ratio”) and the speed ratio of the power split type continuously variable transmission 4 (hereinafter referred to as “T / M speed ratio”). FIG.

  In FIG. 2, “◯” indicates that the high brake HB, the reverse brake RB, and the low clutch LC are engaged.

  The power split type continuously variable transmission 4 has a belt mode and a split mode as power transmission modes when the vehicle 1 moves forward.

  In the belt mode, the high brake HB and the reverse brake RB are released. Then, the low clutch LC is engaged. Thereby, the T / M output shaft 22 and the secondary shaft 32 are directly connected.

  The power input to the T / M input shaft 21 is transmitted to the primary shaft 31 of the continuously variable transmission mechanism 23 to rotate the primary shaft 31 and the primary pulley 33. The rotation of the primary pulley 33 is transmitted to the secondary pulley 34 via the belt 35 and rotates the secondary pulley 34 and the secondary shaft 32. Since the low clutch LC is engaged, the T / M output shaft 22 rotates integrally with the secondary shaft 32. Therefore, in the belt mode, as shown in FIG. 3, the T / M gear ratio matches the belt gear ratio.

  The rotation of the T / M output shaft 22 is transmitted to the ring gear 64 of the differential gear 5 through the output gear 55, the first idle gear 62, the idle shaft 61 and the second idle gear 63. Thereby, the drive shafts 71 and 72 of the vehicle 1 rotate in the forward direction.

  FIG. 4 is a collinear diagram showing the relationship among the rotational speeds of the carrier 51, sun gear 52 and ring gear 53 of the synthesizing gear mechanism 25.

  In the split mode, as shown in FIG. 2, the high brake HB is engaged, and the reverse brake RB and the low clutch LC are released. When the high brake HB is engaged, the ring gear 47 of the constant speed change mechanism 24 is braked. Further, when the low clutch LC is released, the direct connection between the T / M output shaft 22 and the secondary shaft 32 is released.

  The power input to the T / M input shaft 21 is transmitted to the primary shaft 31 of the continuously variable transmission mechanism 23 to rotate the primary shaft 31 and the primary pulley 33. The rotation of the primary pulley 33 is transmitted to the secondary pulley 34 via the belt 35 and rotates the secondary pulley 34 and the secondary shaft 32. As the secondary shaft 32 rotates, the sun gear 52 of the synthesizing gear mechanism 25 rotates.

  Further, since the ring gear 47 of the constant speed change mechanism 24 is braked, the power input to the T / M input shaft 21 causes the carrier 45 of the constant speed change mechanism 24 to revolve and the pinion gear held by the carrier 45. 48 is rotated. As the pinion gear 48 rotates, power is input from the pinion gear 48 to the sun gear 46. As a result, the pinion gear 48 and the split drive gear 42 rotate. The rotation of the split drive gear 42 is transmitted to the split driven gear 43 via the idle gear 44 and rotates the split driven gear 43 and the carrier 51 of the synthesizing gear mechanism 25.

  Since the speed ratio of the constant speed change mechanism 24 is constant and unchanged (fixed), in the split mode, if the power input to the T / M input shaft 21 is constant, the rotation of the carrier 51 of the synthesizing gear mechanism 25 is prevented. It is held at a constant speed. Therefore, when the belt speed ratio is increased, as shown in FIG. 4, the rotational speed of the sun gear 52 of the synthesizing gear mechanism 25 decreases, so that the ring gear 53 (T / M output shaft 22) of the synthesizing gear mechanism 25 Increases rotation speed. As a result, in the split mode, as shown in FIG. 3, the larger the belt speed ratio, the lower the T / M speed ratio.

  The rotation of the T / M output shaft 22 is transmitted to the ring gear 64 of the differential gear 5 through the output gear 55, the first idle gear 62, the idle shaft 61 and the second idle gear 63. Thereby, the drive shafts 71 and 72 of the vehicle 1 rotate in the forward direction.

  In the reverse mode for moving the vehicle 1 backward, the high brake HB and the low clutch LC are released. Then, the reverse brake RB is engaged. Thereby, the split drive gear 42 (sun gear 46) is braked. Due to the braking of the split drive gear 42, the idle gear 44 of the constant speed change mechanism 24 becomes non-rotatable, and the split driven gear 43 and the carrier 51 become non-rotatable.

  The power input to the T / M input shaft 21 is transmitted to the primary shaft 31 of the continuously variable transmission mechanism 23 to rotate the primary shaft 31 and the primary pulley 33. The rotation of the primary pulley 33 is transmitted to the secondary pulley 34 via the belt 35 and rotates the secondary pulley 34 and the secondary shaft 32. As the secondary shaft 32 rotates, the sun gear 52 of the synthesizing gear mechanism 25 rotates. Since the carrier 51 cannot rotate, when the sun gear 52 rotates, the ring gear 53 rotates in the opposite direction to the sun gear 52. The rotation direction of the ring gear 53 is opposite to the rotation direction of the ring gear 53 in the belt mode and the split mode. Then, the T / M output shaft 22 rotates integrally with the ring gear 53. The rotation of the T / M output shaft 22 is transmitted to the ring gear 64 of the differential gear 5 through the output gear 55, the first idle gear 62, the idle shaft 61 and the second idle gear 63. Thereby, the drive shafts 71 and 72 of the vehicle 1 rotate in the reverse direction.

<Electrical configuration>

  FIG. 5 is a block diagram showing a main part of the electrical configuration of the vehicle 1.

  The vehicle 1 is equipped with a plurality of ECUs (electronic control units). Each ECU has a configuration including, for example, a CPU and a memory, and is connected so as to be capable of bidirectional communication using a CAN (Controller Area Network) communication protocol. The plurality of ECUs include an ECU 81 for controlling the drive system.

  The ECU 81 is connected to a primary rotational speed sensor 82, a secondary rotational speed sensor 83, and an output rotational speed sensor 84.

  The primary rotational speed sensor 82 inputs, for example, a pulse signal synchronized with the rotation of the primary pulley 33 of the continuously variable transmission mechanism 23 to the ECU 81. The ECU 81 converts the frequency of the pulse signal input from the primary rotational speed sensor 82 into the rotational speed (primary rotational speed) of the primary shaft 31.

  For example, the secondary rotation speed sensor 83 inputs a pulse signal synchronized with the rotation of the secondary pulley 34 of the continuously variable transmission mechanism 23 to the ECU 81. The ECU 81 converts the frequency of the pulse signal input from the secondary rotational speed sensor 83 into the rotational speed of the secondary shaft 32 (secondary rotational speed).

  The output rotation speed sensor 84 inputs, for example, a pulse signal synchronized with the rotation of the first idle gear 62 to the ECU 81. The ECU 81 converts the frequency of the pulse signal input from the output rotation speed sensor 84 into the rotation speed (output rotation speed) of the T / M output shaft 22.

  The ECU 81 is connected with various valves (not shown) included in a hydraulic device 85 for supplying the operating hydraulic pressure of the power split continuously variable transmission 4 as a control target. The valves include, for example, valves that respectively control the hydraulic pressure for engaging / disengaging the high brake HB, reverse brake RB, and low clutch LC of the power split continuously variable transmission 4.

  The ECU 81 switches between the belt mode and the torque mode by controlling the valve included in the hydraulic device 85 and switching the engagement / release of the high brake HB and the low clutch LC. Switching between the belt mode and the split mode is performed in a state in which the gear ratio of the continuously variable transmission mechanism 23 coincides with a predetermined switching gear ratio. The switching speed ratio is set to a value within a predetermined range including the speed ratio of the constant speed change mechanism 24, preferably the same value as the speed ratio of the constant speed change mechanism 24. The transmission ratio of the constant transmission mechanism 24 is set to the same value as the minimum transmission ratio of the continuously variable transmission mechanism 23, for example.

  Further, the ECU 81 controls a valve included in the hydraulic device 85 to switch between engagement / release of the low clutch LC and the reverse brake RB, thereby switching between the forward mode (belt mode) and the reverse mode.

<Sensor failure processing>

  FIG. 6 is a flowchart showing the flow of sensor failure processing.

  While the vehicle 1 is traveling, the ECU 81 repeatedly executes the sensor failure process shown in FIG.

  In the sensor failure process, first, it is determined whether or not the power transmission mode at the time of failure detection is the split mode (step S1).

  When the power transmission mode is the split mode (YES in step S1), it is determined whether or not a failure of the secondary rotational speed sensor 83 or the output rotational speed sensor 84 is detected (step S2). For example, when a pulse signal is not output from the secondary rotational speed sensor 83 even though a pulse signal is output from the primary rotational speed sensor 82, the ECU 81 detects a failure of the secondary rotational speed sensor 83. Further, when a pulse signal is not output from the output speed sensor 84 even though the vehicle speed of the vehicle 1 is not zero, the ECU 81 detects a failure of the output speed sensor 84.

  If a failure of the secondary rotation speed sensor 83 or the output rotation speed sensor 84 is detected, it is next determined whether or not the detected failure is a failure of the secondary rotation speed sensor 83 (step S3). .

  If the secondary rotational speed sensor 83 is malfunctioning (YES in step S3), the secondary rotational speed is unknown (step S4).

  The secondary rotational speed includes the primary rotational speed acquired from the output pulse signal of the primary rotational speed sensor 82, the output rotational speed acquired from the output pulse signal of the output rotational speed sensor 84, the speed ratio of the constant speed change mechanism 24, and the composition Calculation is performed using the number of teeth of the sun gear 52 and the ring gear 53 of the gear mechanism 25.

As shown in FIG. 7, when the transmission ratio of the constant transmission mechanism 24 is γ _g , the belt transmission ratio is γ _b , and the T / M transmission ratio is γ _all , the carrier 51 and the sun gear 52 of the synthesizing gear mechanism 25 are used. The ratio between the differential rotational speed of the carrier 51 and the differential rotational speed of the ring gear 53 is expressed as 1 / γ _g −1 / γ _b : 1 / γ _all −1 / γ _g .

The ratio (1 / γ _g −1 / γ _b : 1 / γ _all −1 / γ _g ) between the differential rotational speed of the carrier 51 and the sun gear 52 and the differential rotational speed of the carrier 51 and the ring gear 53 is It is equal to the ratio of the reciprocal 1 / _{Z r} of the number of teeth _{Z r} of the reciprocal of the number of teeth _{Z s} 1 / _{Z s} and the ring gear 53. This can be expressed as an expression:
1 / γ _g -1 / γ _b : 1 / γ _all -1 / γ _g = 1 / Z _s : 1 / Z _r (1)
It becomes.

The primary speed and _{N pri,} the secondary rotational speed and _{N sec,} when the output speed and _{N out,} the reciprocal 1 / gamma _b of the belt speed ratio gamma _b,
1 / γ _b = N _sec / N _pri (2)
Next, the reciprocal 1 / gamma _all the T / M gear ratio gamma _all the
1 / γ _all = N _out / N _pri (3)
It becomes.

Substituting Equation (2) and Equation (3) into Equation (1) to eliminate the belt transmission ratio γ _b and T / M transmission ratio γ _all , and then substituting Equation (1) into the secondary rotational speed N _sec Is solved, the following equation (4) can be obtained.

_{N sec = N pri (1 /} γ g -N pri / N out) · Z r / Z s + N pri / γ g
... (4)

  Therefore, the secondary rotational speed can be calculated according to the equation (4).

  After calculating the secondary rotational speed, using the calculated secondary rotational speed and the primary rotational speed obtained from the output pulse signal of the primary rotational speed sensor 82, a pulley ratio (belt transmission ratio) between the primary pulley 33 and the secondary pulley 34 is obtained. ) Is calculated.

  On the other hand, when the detected failure is not a failure of the secondary rotation speed sensor 83 (NO in step S3), that is, when the detected failure is a failure of the output rotation speed sensor 84, the calculation of the secondary rotation speed is not performed. (Skip of step S4), the pulley ratio of the primary pulley 33 and the secondary pulley 34 is calculated using the secondary rotational speed acquired from the output pulse signal of the secondary rotational speed sensor 83.

  Then, the pulley diameters of the primary pulley 33 and the secondary pulley 34 are changed, and the pulley ratio is lowered to a predetermined switching speed ratio (step S5: belt speed change).

  When the pulley ratio falls to the switching gear ratio, the power transmission mode is switched from the split mode to the belt mode (step S6).

  As a result, when the mode is switched from the split mode to the belt mode, the T / M transmission ratio can be prevented from significantly increasing, and the engine speed can exceed the rev limit, resulting in a sudden deceleration of the vehicle due to an overrev or a powerful engine brake. Can be suppressed. Further, the engagement shock of the low clutch LC and the occurrence of damage to the low clutch LC can be suppressed.

  After the power transmission mode is switched to the belt mode, switching from the belt mode to the split mode is prohibited (step S7), and the sensor failure process is terminated.

  If no failure of the secondary rotational speed sensor 83 or the output rotational speed sensor 84 is detected (NO in step S2), the processes in steps S3 to S7 are skipped, and the sensor failure process is terminated.

  If the power transmission mode at the time of failure detection is not the split mode, that is, if the power transmission mode at the time of failure detection is the belt mode (NO in step S1), whether or not a failure of the secondary rotational speed sensor 83 is detected. Is determined (step S8).

  When a failure of the secondary rotational speed sensor 83 is detected (YES in step S8), in the subsequent belt mode, the output rotational speed obtained from the output pulse signal of the output rotational speed sensor 84 is regarded as the secondary rotational speed ( Step S9), the pulley ratio is calculated from the output rotation speed and the primary rotation speed obtained from the output pulse signal of the primary rotation speed sensor 82, and the T / M transmission ratio is set by controlling the pulley ratio (belt transmission ratio). Be controlled.

  Then, switching from the belt mode to the split mode is prohibited (step S7), and the sensor failure process is terminated.

  If no failure of the secondary rotation speed sensor 83 is detected (NO in step S8), it is determined whether or not a failure of the output rotation speed sensor 84 is detected (step S10).

  If a failure of the output rotation speed sensor 84 is detected (YES in step S10), then, the secondary rotation speed acquired from the output pulse signal of the secondary rotation speed sensor 83 is regarded as the output rotation speed (step S11).

  Then, switching from the belt mode to the split mode is prohibited (step S7), and the sensor failure process is terminated. In the subsequent belt mode, the pulley ratio is calculated from the primary rotation speed acquired from the output pulse signal of the primary rotation speed sensor 82 and the secondary rotation speed acquired from the output pulse signal of the secondary rotation speed sensor 83, and the pulley ratio ( The T / M speed ratio is controlled by controlling the belt speed ratio.

  On the other hand, in the belt mode, when any failure of the secondary rotation speed sensor 83 and the output rotation speed sensor 84 is not detected (NO in step S10), the sensor failure processing is thereafter terminated.

<Effect>

  As described above, even if the secondary rotational speed sensor 83 fails, the secondary rotational speed is calculated, so that the pulley ratio (belt transmission ratio) between the primary pulley 33 and the secondary pulley 34 can be calculated. Therefore, it is possible to perform good switching from the split mode to the belt mode, and it is possible to control the T / M speed ratio by controlling the pulley ratio.

  If a failure occurs in the secondary rotational speed sensor 83 or the output rotational speed sensor 84, the differential rotational speed between the secondary shaft 32 and the T / M output shaft 22 cannot be detected, and even if the differential rotational speed can be calculated, Since the calculated value is not guaranteed to be accurate, switching from the belt mode to the split mode is prohibited, and the power transmission mode is fixed to the belt mode. In the split mode, the T / M speed ratio is limited to a certain speed ratio or less, whereas in the belt mode, the speed ratio width of the continuously variable transmission mechanism can be secured as the T / M speed ratio width. Therefore, the vehicle 1 can travel well even after being fixed in the belt mode.

<Modification>

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

  In the above-described embodiment, when the failure of the secondary rotational speed sensor 83 or the output rotational speed sensor 84 is detected, the power transmission mode is fixed to the belt mode (switching to the split mode is prohibited). Even when a failure of the number sensor 82 is detected, the power transmission mode may be fixed to the belt mode in order to prevent the control of the T / M transmission ratio from becoming more unstable. For example, when the pulse signal is output from the secondary rotation speed sensor 83 but no pulse signal is output from the primary rotation speed sensor 82, the ECU 81 detects a failure of the primary rotation speed sensor 82.

  Further, even when the output rotation speed sensor 84 is out of order, the output rotation speed that is the rotation speed of the T / M output shaft 22 can be acquired with appropriate accuracy from the output signal of the vehicle speed sensor provided in the vehicle 1. However, switching from the belt mode to the split mode is not necessarily prohibited.

Substituting Equation (2) and Equation (3) into Equation (1) to eliminate the belt transmission ratio γ _b and T / M transmission ratio γ _all , and then substituting Equation (1) into the output speed Solving for N _out gives the following equation (5).

N _out = N _pri (1 + Z _s / Z _r ) / γ _g −N _sec · Z _s / Z _r
... (5)

  When the output rotation speed sensor 84 fails, the output rotation speed may be calculated according to the equation (5).

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

4 Power split type continuously variable transmission 21 T / M input shaft 22 T / M output shaft 24 Constant transmission mechanism 31 Primary shaft 32 Secondary shaft 33 Primary pulley 34 Secondary pulley 35 Belt 51 Carrier 52 Sun gear 53 Ring gear 54 Pinion gear 81 ECU (Rotation) Number calculation means, mode switching means, mode switching prohibiting means)
82 Primary rotational speed sensor (primary rotational speed detection means)
83 Secondary rotational speed sensor (secondary rotational speed detection means)
84 Output speed sensor (output speed detection means)

Claims (2)

An input shaft, an output shaft, a primary shaft connected to the input shaft, a secondary shaft provided in parallel to the primary shaft, a primary pulley supported by the primary shaft, and supported by the secondary shaft A secondary pulley, a belt wound around the primary pulley and the secondary pulley, a carrier that rotatably supports a pinion gear, a sun gear that is engaged with the pinion gear and that is connected to the secondary shaft, and a gear that is engaged with the pinion gear A ring gear connected to the output shaft, and a constant speed change mechanism for shifting the power input to the input shaft at a constant speed ratio and transmitting the power to the carrier. A belt mode in which a sun gear and the ring gear are directly connected, and a direct connection between the sun gear and the ring gear. Is divided, there is provided a control device for controlling the constant power transmission mechanism power via is configured to switch to split mode and is transmitted to the carrier split type continuously variable transmission,
Primary rotational speed detection means for detecting the rotational speed of the primary shaft;
Secondary rotational speed detection means for detecting the rotational speed of the secondary shaft;
Output rotational speed detection means for detecting the rotational speed of the output shaft;
When the secondary rotational speed detection means fails, the rotational speed detected by the primary rotational speed detection means, the rotational speed detected by the output rotational speed detection means, the gear ratio of the constant speed change mechanism, and the sun gear and And a rotation speed calculation means for calculating the rotation speed of the secondary shaft based on the number of teeth of the ring gear. When one of the secondary rotational speed detection means or the output rotational speed detection means fails in the split mode, after changing the pulley ratio between the primary pulley and the secondary pulley to a predetermined switching gear ratio, the split mode Mode switching means for switching from to the belt mode;
2. The control according to claim 1, further comprising mode switching prohibiting means for prohibiting switching from the belt mode to the split mode when one of the secondary rotational speed detecting means or the output rotational speed detecting means fails. apparatus.

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