JP5926390B2 - Control device and control method for automatic transmission - Google Patents

Description

  The present invention relates to a control device and a control method for a continuously variable transmission that can suppress a change in gear ratio.

  2. Description of the Related Art A continuously variable transmission that controls a gear ratio steplessly by passing a belt, a chain, or the like over a set of primary and secondary pulleys and changing the groove width of each pulley is widely used in vehicle transmissions.

  In such a continuously variable transmission, there is a case where so-called hunting in which the gear ratio varies during traveling occurs. For example, when the driver switches from the driving range (D range) to the N range during driving, the driving force applied to the continuously variable transmission from the engine is lost, causing the continuously variable transmission to sway, causing the sway. As a result, hunting of the gear ratio may occur.

  In JP2011-33114A, as a countermeasure for such a gear ratio hunting, when the driver switches from the driving range (D range) to the N range during driving, the feedback gain is set to a small gain so that the feedback sensitivity is reduced. A transmission control device for a continuously variable transmission that desensitizes and suppresses rotational hunting is known.

  In the prior art described in JP2011-33114A, control for preventing hunting is executed in response to an operation related to the running state by the driver.

  However, gear ratio hunting can occur in addition to operations that the driver is involved in traveling the vehicle. For example, hunting due to vibration of the transmission itself or hunting due to the control state of the transmission can occur. With the above-described conventional technology, it is not possible to suppress such hunting of the gear ratio that is not based on the operation of the driver.

  In addition, when the driver performs operations related to vehicle travel, such as changing the speed range or operating the accelerator or brake, the driver can predict changes in the vehicle's travel performance, so there is a change in the gear ratio. Even so, the tolerance for the uncomfortable feeling felt by the driver is high. On the other hand, the ratio ratio hunting that occurs when the driver cannot predict a change in the driving performance of the vehicle increases the sense of discomfort given to the driver.

  The present invention has been made in view of such problems, and provides a control device and a control method for a continuously variable transmission that can prevent the driver from feeling uncomfortable by suppressing the occurrence of a change in the gear ratio. For the purpose.

  According to one embodiment of the present invention, the actual gear ratio can be changed by changing the winding diameter of a power transmission belt mounted on a vehicle and clamped by a set of pulleys and hydraulic pressure supplied to the set of pulleys. A control device for a continuously variable transmission, which calculates a target gear ratio based on the state of the vehicle, outputs an instruction value so that the actual gear ratio follows the target gear ratio, and controls the continuously variable transmission A shift control unit that controls the value and predicts the occurrence of fluctuations in the actual gear ratio when it detects or estimates that the change amount per unit time of the control value is larger than the change amount per unit time of the indicated value And a transmission ratio fluctuation suppressing unit that executes control for suppressing fluctuations in the actual transmission ratio when a change in the actual transmission ratio is detected by the transmission ratio fluctuation prediction unit. .

  Further, according to another embodiment of the present invention, the actual transmission ratio is changed by changing the winding diameter of the power transmission belt mounted on the vehicle and clamped by the hydraulic pressure supplied to the set of pulleys and the set of pulleys. Is a control method for a continuously variable transmission, in which a target gear ratio is calculated based on the state of the vehicle, an instruction value is output so that the actual gear ratio follows the target gear ratio, and the continuously variable transmission When the control value of the machine control value is detected or estimated that the amount of change per unit time of the control value is greater than the amount of change per unit time of the indicated value And a procedure for executing control for suppressing the fluctuation of the actual gear ratio when the fluctuation of the actual gear ratio is predicted.

  According to the above aspect, when the change in the control value of the continuously variable transmission is larger than the change in the command value for controlling the actual gear ratio, the actual gear ratio is predicted to vary, and the actual gear ratio varies. When it is predicted that control is performed, control for suppressing fluctuations in the actual gear ratio is executed. By configuring in this way, it is possible to suppress the occurrence of fluctuations in the actual gear ratio that are not intended by the driver, thereby preventing the occurrence of hunting in the actual gear ratio and giving the driver a sense of incongruity. Can be prevented.

FIG. 1 is a schematic configuration diagram of a vehicle equipped with a continuously variable transmission according to an embodiment of the present invention. FIG. 2 is an explanatory diagram showing an example of the configuration of the transmission controller according to the embodiment of the present invention. FIG. 3 is an explanatory diagram illustrating an example of a shift map according to the embodiment of this invention. FIG. 4 is an explanatory diagram of a hydraulic circuit centering on the hydraulic control circuit of the embodiment of the present invention. FIG. 5 is a flowchart of hunting prevention control according to the embodiment of the present invention. FIG. 6 is an explanatory diagram showing the actual gear ratio hunting prevention control according to the embodiment of the present invention. FIG. 7 is an explanatory diagram illustrating the actual gear ratio hunting prevention control according to the embodiment of the present invention. FIG. 8 is an explanatory diagram of the first to third threshold values according to the embodiment of this invention. FIG. 9 is an explanatory diagram showing the relationship between the threshold value and the actual gear ratio in the primary pulley according to the embodiment of the present invention. FIG. 10 is an explanatory diagram showing the relationship between the threshold value and the actual gear ratio in the secondary pulley of the embodiment of the present invention.

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

  FIG. 1 is a schematic configuration diagram of a vehicle equipped with a continuously variable transmission according to an embodiment of the present invention. The vehicle includes an engine 1 as a power source. The output rotation of the engine 1 is via a torque converter 2 with a lock-up clutch, a first gear train 3, a continuously variable transmission (hereinafter simply referred to as "transmission 4"), a second gear train 5, and a final reduction gear 6. Is transmitted to the drive wheel 7. The second gear train 5 is provided with a parking mechanism 8 that mechanically locks the output shaft of the transmission 4 at the time of parking.

  Further, the vehicle is supplied with the rotation of the engine 1 and is driven by using a part of the power of the engine 1. The electric oil pump 10 e is driven by receiving power supply from the battery 13. Is provided. Further, the transmission 4 has a hydraulic pressure control circuit 11 that regulates hydraulic pressure (hereinafter referred to as “line pressure”) supplied from at least one of the mechanical oil pump 10 m and the electric oil pump 10 e and supplies the hydraulic pressure to each part of the transmission 4. And a controller 12 for controlling the hydraulic control circuit 11 and the engine 1.

  The transmission 4 includes a continuously variable transmission mechanism (hereinafter referred to as “variator 20”) and an auxiliary transmission mechanism 30 provided in series with the variator 20. “Provided in series” means that the variator 20 and the auxiliary transmission mechanism 30 are provided in series in the power transmission path. The auxiliary transmission mechanism 30 may be directly connected to the output shaft of the variator 20 as in this example, or may be connected via another transmission or power transmission mechanism (for example, a gear train).

  The variator 20 is a belt-type continuously variable transmission mechanism that includes a primary pulley 21, a secondary pulley 22, and a belt (V belt) 23 that is wound around the pulleys 21 and 22. Each of the pulleys 21 and 22 includes a fixed conical plate, a movable conical plate that is arranged with a sheave surface facing the fixed conical plate, and forms a V-groove between the fixed conical plate, and a rear surface of the movable conical plate. And hydraulic cylinders 23a and 23b for displacing the movable conical plate in the axial direction. When the hydraulic pressure supplied to the hydraulic cylinders 23a and 23b is adjusted, the width of the V groove changes, the contact radius between the belt 23 and each pulley 21 and 22 changes, and the actual gear ratio vRatio of the variator 20 changes steplessly. To do.

  The subtransmission mechanism 30 is a transmission mechanism having two forward speeds and one reverse speed. The sub-transmission mechanism 30 is connected to a Ravigneaux type planetary gear mechanism 31 in which two planetary gear carriers are connected, and a plurality of friction elements connected to a plurality of rotating elements constituting the Ravigneaux type planetary gear mechanism 31 to change their linkage state. Fastening elements (Low brake 32, High clutch 33, Rev brake 34) are provided. When the hydraulic pressure supplied to each of the frictional engagement elements 32 to 34 is adjusted and the engagement / release state of each of the frictional engagement elements 32 to 34 is changed, the gear position of the auxiliary transmission mechanism 30 is changed.

  For example, if the Low brake 32 is engaged and the High clutch 33 and the Rev brake 34 are released, the gear position of the subtransmission mechanism 30 is the first speed. If the high clutch 33 is engaged and the low brake 32 and the rev brake 34 are released, the speed stage of the subtransmission mechanism 30 becomes the second speed having a smaller speed ratio than the first speed. Further, if the Rev brake 34 is engaged and the Low brake 32 and the High clutch 33 are released, the shift speed of the subtransmission mechanism 30 is reverse. In the following description, the transmission 4 is expressed as “the transmission 4 is in the low speed mode” when the shift stage is the first speed, and “the transmission 4 is in the high speed mode” when the speed is the second speed. .

  The controller 12 is a control device that comprehensively controls the engine 1 and the transmission 4. As shown in FIG. 2, the CPU 12, a storage device 122 including a RAM / ROM, an input interface 123, an output interface 124, , And a bus 125 for interconnecting them.

  The input interface 123 includes an output signal of an accelerator opening sensor 41 for detecting an accelerator pedal opening (hereinafter referred to as “accelerator opening APO”), an input rotational speed of the transmission 4 (= the rotational speed of the primary pulley 21). , Hereinafter referred to as “primary rotational speed Npri”), an output signal from the rotational speed sensor 42, an output signal from the vehicle speed sensor 43 that detects the traveling speed of the vehicle (hereinafter referred to as “vehicle speed VSP”), and the transmission 4. The output signal of the oil temperature sensor 44 for detecting the oil temperature of the engine, the output signal of the inhibitor switch 46 for detecting the position of the select lever 45, the output signal of the brake sensor 47 for detecting the brake pedal depression amount and the brake hydraulic pressure, etc. Entered.

  The storage device 122 stores a control program for the engine 1, a shift control program for the transmission 4, and a shift map (FIG. 3) used in the shift control program. The CPU 121 reads and executes a shift control program stored in the storage device 122, performs various arithmetic processes on various signals input via the input interface 123, and outputs a fuel injection signal, an ignition timing signal, a throttle An opening signal and a shift control signal are generated, and the generated shift control signal is output to the hydraulic control circuit 11 via the output interface 124. Various values used in the arithmetic processing by the CPU 121 and the arithmetic results are appropriately stored in the storage device 122.

  The hydraulic control circuit 11 includes a plurality of flow paths and a plurality of hydraulic control valves. The hydraulic control circuit 11 controls a plurality of hydraulic control valves on the basis of the shift control signal from the controller 12 to switch the hydraulic pressure supply path, and obtains the necessary hydraulic pressure from the hydraulic pressure generated by the mechanical oil pump 10m or the electric oil pump 10e. This is adjusted and supplied to each part of the transmission 4. As a result, the actual gear ratio vRatio of the variator 20 and the gear position of the subtransmission mechanism 30 are changed, and the transmission 4 is shifted.

  FIG. 3 shows an example of the shift map stored in the storage device 122 of the controller 12 of the present embodiment.

  On the shift map, the operating point of the transmission 4 is determined based on the vehicle speed VSP and the primary rotational speed Npri. The inclination of the line connecting the operating point of the transmission 4 and the zero point of the lower left corner of the transmission map is obtained by multiplying the actual transmission ratio of the transmission 4 (the actual transmission ratio vRatio of the variator 20 by the actual transmission ratio subRatio of the auxiliary transmission mechanism 30). The actual transmission ratio, hereinafter referred to as “through transmission ratio Ratio”). Similar to the shift map of the conventional belt type continuously variable transmission, a shift line is set for each accelerator opening APO, and the shift of the transmission 4 is selected according to the accelerator opening APO. This is done according to the shift line. For simplicity, FIG. 3 shows a full load line (shift line when accelerator opening APO = 8/8), partial line (shift line when accelerator opening APO = 4/8), coast line (accelerator opening). Only the shift line when the degree APO = 0 is shown.

  When the transmission 4 is in the low speed mode, the transmission 4 has the low speed mode low line obtained by maximizing the actual transmission ratio vRatio of the variator 20 and the low speed mode highest High obtained by minimizing the actual transmission ratio vRatio of the variator 20. You can shift between the lines. At this time, the operating point of the transmission 4 moves in the A region and the B region. On the other hand, when the transmission 4 is in the high speed mode, the transmission 4 can be obtained by maximizing the actual transmission ratio vRatio of the variator 20 and the high speed mode obtained by minimizing the actual transmission ratio vRatio of the variator 20. The speed can be changed between the highest lines. At this time, the operating point of the transmission 4 moves in the B region and the C region.

  The gear ratio of each gear stage of the sub-transmission mechanism 30 is such that the gear ratio corresponding to the low speed mode highest line (low speed mode highest high gear ratio) corresponds to the high speed mode lowest line (high speed mode lowest gear ratio). It is set to be smaller than that. Accordingly, a low speed mode ratio range that is a range of the through speed ratio Ratio of the transmission 4 that can be taken in the low speed mode and a high speed mode ratio range that is a range of the through speed ratio Ratio of the transmission 4 that can be taken in the high speed mode are partially obtained. When the operating point of the transmission 4 is in the B region sandwiched between the high-speed mode lowest line and the low-speed mode highest line, the transmission 4 can select either the low-speed mode or the high-speed mode. ing.

  The controller 12 sets the through speed ratio Ratio corresponding to the vehicle speed VSP and the accelerator opening APO (the driving state of the vehicle) as the reaching through speed ratio DRatio with reference to the speed change map. The reached through speed ratio DRatio is a target value that the through speed ratio Ratio should finally reach in the driving state. Then, the controller 12 sets a target through speed ratio tRatio that is a transient target value for causing the through speed ratio Ratio to follow the reached through speed ratio DRatio with a desired response characteristic, and the through speed ratio Ratio is the target through speed ratio. The variator 20 and the auxiliary transmission mechanism 30 are controlled so as to coincide with the ratio tRatio.

  On the shift map, a mode switching shift line (1-2 shift line of the subtransmission mechanism 30) for performing the shift of the subtransmission mechanism 30 is set to overlap the low speed mode Highest line. The through speed ratio corresponding to the mode switching speed line (hereinafter referred to as “mode switching speed ratio mRatio”) is equal to the low speed mode maximum High speed ratio.

  When the operating point of the transmission 4 crosses the mode switching speed line, that is, when the through speed ratio Ratio of the transmission 4 changes across the mode switching speed ratio mRatio, the controller 12 performs the mode switching speed control. Do. In the mode switching shift control, the controller 12 shifts the auxiliary transmission mechanism 30, and changes the actual transmission ratio vRatio of the variator 20 in a direction opposite to the direction in which the actual transmission ratio subRatio of the auxiliary transmission mechanism 30 changes. I do.

  In the coordinated shift, when the through speed ratio Ratio of the transmission 4 changes from a state larger than the mode switching speed ratio mRatio to a smaller state, the controller 12 changes the gear position of the subtransmission mechanism 30 from the first speed to the second speed. (Hereinafter referred to as “1-2 shift”) and the actual transmission ratio vRatio of the variator 20 is changed to the higher transmission ratio side. Conversely, when the through speed ratio Ratio of the transmission 4 changes from a state smaller than the mode switching speed ratio mRatio to a larger state, the controller 12 changes the gear position of the subtransmission mechanism 30 from the second speed to the first speed ( Hereinafter, it is referred to as “2-1 speed change”) and the actual speed ratio vRatio of the variator 20 is changed to the lower speed ratio.

  The reason why the cooperative shift is performed at the time of the mode switching shift is to suppress the driver's uncomfortable feeling due to the change in the input rotation caused by the step of the through speed ratio Ratio of the transmission 4. Further, the mode switching shift is performed when the actual transmission ratio vRatio of the variator 20 is the highest transmission ratio. In this state, the torque input to the auxiliary transmission mechanism 30 is the same as the torque input to the variator 20 at that time. This is because shifting shock of the subtransmission mechanism 30 can be mitigated by shifting the subtransmission mechanism 30 in this state.

  Further, according to the shift map, when the vehicle stops, the actual speed ratio vRatio of the variator 20 becomes the lowest speed ratio, and the speed stage of the subtransmission mechanism 30 becomes the first speed.

  FIG. 4 is an explanatory diagram of a hydraulic circuit centered on the hydraulic control circuit 11 according to the embodiment of the present invention.

  The hydraulic control circuit 11 receives the hydraulic pressure supplied from the mechanical oil pump 10 m, regulates the hydraulic pressure, and supplies the hydraulic pressure to each of the variator 20, the torque converter 2, and the auxiliary transmission mechanism 30.

  The hydraulic control circuit 11 includes a regulator valve 230, a secondary hydraulic control valve 220, a shift control valve 210, and a lockup clutch control valve 240.

  The regulator valve 230 is a control valve that regulates the hydraulic pressure from the mechanical oil pump 10 m to a predetermined line pressure and supplies it to the oil passage 200.

  The secondary hydraulic control valve 220 is a control valve that regulates the secondary hydraulic pressure supplied to the hydraulic cylinder 23 b of the secondary pulley 22 using the line pressure as the original pressure.

  The shift control valve 210 is a control valve that regulates the primary hydraulic pressure supplied to the hydraulic cylinder 23a of the primary pulley 21 using the line pressure as the original pressure.

  The lockup clutch control valve 240 regulates the release pressure supplied to the lockup chamber of the torque converter 2. The fastening force of the lockup clutch is controlled by the differential pressure between the apply pressure and the release pressure of the torque converter 2.

  The regulator valve 230, the secondary hydraulic control valve 220, and the lock-up clutch control valve 240 are driven by solenoids, and each valve is controlled by controlling the duty ratio of these solenoids according to an instruction from the controller 12. The hydraulic pressure by is controlled.

  Next, hunting prevention control in the transmission 4 configured as described above will be described.

  While the vehicle is traveling, the controller 12 sends an instruction to the hydraulic control circuit 11 to control the actual speed ratio of the transmission 4 so that the actual speed ratio follows the target speed ratio.

  At this time, so-called hunting may occur in which the actual transmission ratio of the transmission 4, particularly the variator 20, fluctuates in a short cycle. For example, during steady running where the vehicle speed is equal to or higher than a certain speed and the actual gear ratio is relatively low, hunting may occur in which the transmission 4 resonates and the actual gear ratio fluctuates in a short cycle. In addition, when a thrust ratio prediction error occurs, or when a relatively large feedback gain is set and belt slippage occurs due to deterioration of parts (wear, etc.), the primary pulley and secondary pulley The thrust ratio balance may be lost and hunting of the actual transmission ratio may occur. These occur particularly at an actual gear ratio on the relatively high side, and can occur even when the actual oil pressure is normally controlled with respect to the command oil pressure. Also, when the actual oil pressure cannot be controlled normally with respect to the command oil pressure, the thrust ratio may be unbalanced due to a delay in oil pressure response, oil vibration, belt slip, etc., and actual gear ratio hunting may occur. . These occur particularly at a relatively high actual gear ratio. The reason why the actual gear ratio is generated on the relatively high side in this way is that the hydraulic pressure of the secondary pulley 22 is relatively low, so that the stability of the hydraulic pressure is low, and it is easily affected by the vibration of the hydraulic pressure. This is because the influence of the above becomes large.

  The actual speed ratio of the variator 20 is controlled by the hydraulic control circuit 11. However, the actual speed ratio of the variator 20 is short due to a delay or deviation of the solenoid of the hydraulic control circuit 11 in response to an instruction from the controller 12. Hunting that varies with period may occur.

  In contrast to such actual speed ratio hunting, the embodiment of the present invention is configured to prevent occurrence of actual speed ratio hunting by the following control.

  Specifically, when it is predicted that hunting of the actual gear ratio will occur based on the state of the transmission 4, the controller 12 operates the transmission 4 so that hunting of the actual gear ratio does not occur. Control. Details will be described below.

  FIG. 5 is a flowchart of the anti-hunting control executed by the controller 12 according to the embodiment of this invention.

  The flowchart shown in FIG. 5 is executed by the controller 12 at a predetermined cycle (for example, at an interval of 10 ms) when it is determined that the vehicle is running.

  First, the controller 12 determines whether or not it has been detected that a switch related to the operation of the electrical equipment provided in the vehicle has been opened / closed (ON / OFF operation) by the driver. When there is no operation of a switch etc., it transfers to step S120. If an operation such as a switch is detected, the process proceeds to step S140.

  The vehicle is equipped with a battery 13 and its electric power is supplied to various electrical equipment (air conditioner, wiper, light, car navigation, audio, room light, power window). When the ON / OFF operation of the electrical equipment switch is performed, the voltage of the battery 13 changes due to the change in the actual current value output by the battery 13. At this time, the voltage supplied to the solenoid of the hydraulic control circuit 11 changes, so that between the indicated value to the solenoid provided in each control valve and the actual hydraulic pressure brought about by the actual operation of the solenoid. There is a risk that hunting of the actual gear ratio occurs as a result. Accordingly, when the ON / OFF operation of the switch of the electrical equipment is performed, it is estimated that the change amount per unit time of the actual current value becomes larger than the change amount per unit time of the command current value. Similarly, it is estimated that the change amount per unit time of the actual oil pressure is larger than the change amount per unit time of the command oil pressure.

  Thus, when the operation of the switch of the electrical equipment is detected, there is a high possibility that hunting of the actual gear ratio will occur. Therefore, when an operation of a switch or the like of the electrical equipment is detected, hunting prevention control is performed in subsequent steps S140 to S220.

  Next, in step S120, the controller 12 determines whether or not the actual current values of the various solenoids provided in the hydraulic control circuit 11 have changed with respect to the command current value. If the actual current value of the solenoid has not changed, the process proceeds to step S130. If it is determined that the actual current value of the solenoid has changed, the process proceeds to step S140.

  The solenoid is provided with a current detection circuit for detecting an actual current value, and the controller 12 monitors the actual current value detected by each solenoid provided in the hydraulic control circuit 11. Here, when the actual current value of the solenoid fluctuates with respect to the instruction value (instruction current value) of the controller 12, a difference occurs between the instruction oil pressure and the actual oil pressure, and as a result, hunting of the actual gear ratio occurs. There is a fear.

  As described above, when it is detected that the fluctuation of the actual current value supplied to the solenoid has occurred, there is a high possibility that hunting of the actual gear ratio will occur. For this reason, when a change in the actual current value is detected, hunting prevention control is performed in subsequent steps S140 to S220.

  Examples of cases where no switch operation is detected in step S110 and voltage fluctuation is detected in step S120 include engagement / release of a lockup clutch. Engagement / release of the lockup clutch is performed by the controller 12 controlling the lockup clutch control valve 240 based on the state of the vehicle. At this time, the actual current value varies depending on the operation of the solenoid provided in the lockup clutch control valve 240. That is, actual current fluctuation occurs without detecting switch operation.

  Next, in step S130, the controller 12 determines whether or not the actual oil pressure in the oil pressure control circuit 11 has changed with respect to the command oil pressure. If the actual oil pressure has not changed with respect to the command oil pressure, the process returns to step S110. When it is determined that the actual oil pressure has changed with respect to the command oil pressure, the process proceeds to step S140. In the present embodiment, the actual hydraulic pressure and the command hydraulic pressure are pulley hydraulic pressures for the primary pulley 21 and the secondary pulley 22 of the variator 20.

  The hydraulic pressure control circuit 11 is provided with a hydraulic pressure detection device that detects actual hydraulic pressure, and the controller 12 monitors the actual hydraulic pressure detected by the hydraulic pressure control circuit 11. When the actual oil pressure fluctuates with respect to the command value of the controller 12, a difference occurs between the command oil pressure and the actual oil pressure, and as a result, there is a possibility that hunting of the actual gear ratio occurs.

  Thus, when it is detected that the actual hydraulic pressure has changed, there is a high possibility that hunting of the actual gear ratio will occur. Therefore, when a change in the actual hydraulic pressure is detected, hunting prevention control is performed in subsequent steps S140 to S220.

  In the case where the switch operation is not detected in step S110, the voltage fluctuation is not detected in step S120, and the oil pressure fluctuation is detected in step S130, for example, the oil pressure fluctuation occurs due to the pulsation of the discharge oil pressure of the mechanical oil pump 10m. This is the case.

  As described above, when the controller 12 predicts that actual transmission ratio hunting occurs in the transmission 4 by the processing from step S110 to step S130, the controller 12 executes the control after step S140. That is, when the controller 12 detects or estimates that the actual control value (actual current value, actual voltage, etc.) varies greatly with respect to the control instruction value variation, the gear ratio variation prediction predicts the actual gear ratio variation. Configured as part. Control may be performed such that the hunting determination flag is established when it is determined that the process proceeds to S140 in the processing of steps S110 to S130, and the subsequent processing of step S140 is executed when the hunting determination flag is established.

  In step S140, the controller 12 determines the magnitude of fluctuation of the actual current ratio, the magnitude of fluctuation of the hydraulic pressure, and the magnitude of fluctuation of the actual transmission ratio based on the difference between the target transmission ratio and the actual transmission ratio. For each of these, a first determination process is performed for comparison with a first threshold.

  If it is determined that at least one of the magnitude of the fluctuation of the actual current value, the magnitude of the fluctuation of the hydraulic pressure, and the magnitude of the fluctuation of the actual gear ratio exceeds the first threshold value set for each, the process proceeds to step S150. . Otherwise, the process proceeds to step S160.

  The magnitude of the fluctuation indicates the amount of change per unit time, and the controller 12 obtains the actual current value, the hydraulic pressure, and the actual gear ratio by time differentiation or the like.

  In addition, the first threshold value is likely to cause hunting of the actual gear ratio with respect to each of the magnitude of fluctuation of the actual current value, the magnitude of fluctuation of the hydraulic pressure, and the magnitude of fluctuation of the actual gear ratio. The value is set to such a level that it is sufficiently determined that the situation is occurring.

  If it is determined that at least one of the magnitude of the fluctuation of the actual current value, the magnitude of the fluctuation of the hydraulic pressure, and the magnitude of the fluctuation of the actual gear ratio exceeds the first threshold value set for each, the process proceeds to step S150. Then, the controller 12 controls the lock-up clutch of the torque converter 2 to a slip state or a released state.

  By setting the lock-up clutch of the torque converter 2 to the slip state or the released state, the torque converter 2 is brought into the converter state, and the hydraulic oil in the torque converter 2 acts as a damping function to reduce hunting of the actual gear ratio. This prevents the driver from feeling uncomfortable.

  In step S150, the lockup clutch of the torque converter 2 may be controlled to a slip state. In this case, after the slip state is once controlled, when it is determined that the first threshold value is exceeded even after the expiration of a timer, which will be described later, the control may be performed in the released state. After the control in step S150, the process proceeds to step S220.

  If it is determined in step S140 that at least one of the magnitude of the fluctuation of the current value, the magnitude of the fluctuation of the hydraulic pressure, and the magnitude of the fluctuation of the actual gear ratio does not exceed the first threshold value set for each of them. The process proceeds to step S160.

  In step S160, the controller 12 executes a second determination process for comparing each of the magnitude of fluctuation of the actual current value, the magnitude of fluctuation of the hydraulic pressure, and the magnitude of fluctuation of the actual gear ratio with the second threshold value. To do.

  If it is determined that at least one of the magnitude of the fluctuation of the actual current value, the magnitude of the fluctuation of the hydraulic pressure, and the magnitude of the fluctuation of the actual gear ratio exceeds the second threshold value set for each, the process proceeds to step S170. . Otherwise, the process proceeds to step S180.

  In step S170, the control hydraulic pressure (hereinafter referred to as "belt pressure") for clamping the belt 23 in the secondary pulley 22 of the variator 20 is increased.

  By increasing the belt pressure and increasing the clamping force of the belt 23, the fluctuation ratio of the actual speed ratio is reduced, and as a result, hunting of the actual speed ratio can be suppressed. After the control in step S170, the process proceeds to step S220.

  If it is determined in step S160 that at least one of the magnitude of the fluctuation of the actual current value, the magnitude of the fluctuation of the hydraulic pressure, and the magnitude of the fluctuation of the actual gear ratio does not exceed the second threshold value set for each Proceeds to step S180.

  In step S180, the controller 12 executes a third determination process for comparing each of the magnitude of the fluctuation of the actual current value, the magnitude of the fluctuation of the hydraulic pressure, and the magnitude of the fluctuation of the actual gear ratio with the third threshold value. To do.

  When it is determined that at least one of the magnitude of the fluctuation of the actual current value, the magnitude of the fluctuation of the hydraulic pressure, and the magnitude of the fluctuation of the actual gear ratio exceeds the third threshold set for each, the process proceeds to step S190. . Otherwise, the process proceeds to step S210.

  In step S190, the controller 12 sets the feedback gain in the control of the transmission 4 to zero.

  In the control of the variator 20 of the transmission 4, the controller 12 performs feedback control based on the deviation between the target gear ratio and the actual gear ratio to cause the actual gear ratio to follow the target gear ratio. When the deviation is large, the controller 12 adds a value obtained by multiplying the deviation by a predetermined feedback gain to the target speed ratio in order to approach the target speed ratio, and gives an instruction to the hydraulic control circuit 11.

  Here, when the feedback value is large, the control value may cause overshoot / undershoot, and as a result, the actual gear ratio hunting may occur. Therefore, in step S190, the controller 12 sets the feedback gain to zero. That is, the actual speed ratio is not fed back with respect to the target speed ratio. By controlling in this way, hunting of the actual gear ratio due to overshoot / undershoot can be prevented. After the control in step S190, the process proceeds to step S220.

  In Step S180, when it is determined that at least one of the magnitude of the fluctuation of the actual current value, the magnitude of the fluctuation of the hydraulic pressure, and the magnitude of the fluctuation of the actual gear ratio does not exceed the third threshold set for each. Proceeds to step S210.

  In step S <b> 210, the controller 12 sets a dead zone for deviation in the control of the transmission 4. Usually, in the controller 12, a predetermined dead band width is set with emphasis on stability. The normally set dead band width does not cause a change in the actual speed ratio (actual value) with respect to a slight change in the target speed ratio (indicated value) and follows the actual speed ratio with respect to the change in the target speed ratio. The width is set so as to satisfy both of the fact that the property hardly delays. On the other hand, the width of the dead zone set in step S210 is set larger than the normally set dead zone width, and is set with an emphasis on stability for preventing fluctuations rather than followability. That is, the followability with respect to the target speed ratio is lower than the normally set dead band width, but the control is slowed down to improve the stability. Thereby, hunting of the actual gear ratio can be suppressed. After the control in step S210, the process proceeds to step S220.

  In step S220, a timer for a predetermined time is set and timer counting is started. In step S221, the process waits until the timer expires. The timer is set as a hysteresis from the execution of the above-described control in steps S150, S170, S190, and S210 to the next control.

  In step S221, when the timer expires, the process proceeds to step S230. In step S230, it is determined whether or not the actual gear ratio hunting has been eliminated. Specifically, it is determined whether or not the magnitude of the change in the actual speed ratio detected as described above is sufficiently small to determine that the actual speed ratio hunting has been eliminated.

  If it is determined that the actual gear ratio hunting has not been resolved, the process returns to step S140, and the control of steps S140 to S230 is repeated. If it is determined that the actual gear ratio hunting has been eliminated, the control according to this flowchart is terminated.

  As described above, the controller 12 predicts the occurrence of the actual gear ratio hunting by the processing of the flowchart of FIG. 5, and when the occurrence of the actual gear ratio hunting is predicted, the control for preventing the occurrence of the hunting is performed. I do. That is, the controller 12 performs control as in steps S140 to S230 in FIG. 5 to suppress the change in the actual gear ratio, thereby configuring the gear ratio fluctuation suppressing unit.

  As will be described later with reference to FIG. 8, the first, second, and third threshold values in the hunting prevention control are set so that the respective determination criteria are the first threshold value> the second threshold value> the third threshold value. Is done. These threshold values may be changed according to the current actual transmission ratio of the transmission, as will be described later.

  In addition, when the first determination process of step S140 is YES and the torque converter 2 is brought into the converter state by the process of step S150, and the end determination of step S230 is NO, the first determination process of step S140 is performed again. I do. At this time, if the first determination process is NO, the released lock-up clutch is engaged and returned to the lock-up state. Similarly, the second determination process in step S160 is YES, and the belt pressure of the secondary pulley 22 is increased in step S170. Thereafter, when the second determination process in step S160 is NO, the belt pressure of the secondary pulley 22 is decreased. Similarly, the third determination process in step S180 is YES, and the feedback gain of the actual gear ratio is made zero in step S190. Thereafter, when the second determination process in step S180 is NO, the feedback gain of the actual gear ratio is increased. Similarly, the third determination process in step S180 is NO, and a dead zone for the actual gear ratio deviation is set in step S210. Thereafter, if it is determined in step S230 that the actual gear ratio hunting has been eliminated, the dead zone of the actual gear ratio deviation is restored.

  6 and 7 are explanatory diagrams illustrating the actual gear ratio hunting prevention control by the controller 12 according to the embodiment of this invention.

  FIG. 6 shows, from the top, vehicle speed, actual gear ratio, switch ON / OFF determination, solenoid actual current value variation, actual current value variation determination, oil pressure variation, oil pressure variation determination, and hunting determination based on these determinations. Each of the flags is shown as a time chart with time on the horizontal axis.

  In FIG. 6, it is assumed that the vehicle is traveling with the vehicle speed and the actual gear ratio being substantially constant.

  At this time, when the operation of the switch related to the operation of the electrical equipment is detected at the timing t1, the controller 12 detects the solenoid due to the fluctuation of the actual current value of the power supplied to the solenoid in step S110 of FIG. The occurrence of hunting of the actual gear ratio is predicted by the change in the operation. At this time, the hunting flag is established, and the process proceeds to the processing after step S140 in FIG.

  Similarly, if it is determined at timing t2 that the actual current value of the solenoid has changed, in step S120 in FIG. 5 described above, the actual speed ratio hunting is performed due to the change in operation of the solenoid due to the change in the actual current value. Occurrence is predicted, and the process proceeds to step S140 and subsequent steps in FIG.

  Similarly, if it is determined at timing t3 that the difference between the command hydraulic pressure and the actual hydraulic pressure has fluctuated, the occurrence of hunting of the actual hydraulic gear ratio is predicted in step S120 of FIG. The process proceeds to step S140 and subsequent steps in FIG.

  FIG. 7 shows the actual transmission ratio, hunting determination flag, lockup clutch state, actual transmission ratio feedback gain, actual transmission ratio feedback amount, and the range of deviation of the actual transmission ratio from the target transmission ratio. It is shown as a time chart with the horizontal axis.

  In FIG. 7, when the actual gear ratio hunting is predicted to occur or has occurred (the hunting flag is established) based on the determination in steps S <b> 110 to 130 in FIG. 5 described above, the processing after step S <b> 140 in FIG. 5 is performed. It is explanatory drawing when is performed.

  When the first determination process is performed in step S140 of FIG. 5 and it is determined that the fluctuation range of the actual gear ratio has exceeded the first threshold, the controller 12 performs the process of step S150 of FIG. An instruction is given to the hydraulic control circuit 11 so that the lock-up clutch is slipped or released (timing t3). As a result, the lockup clutch is released, the connection of the driving force between the engine 1 and the transmission 4 is released, and the hunting of the actual gear ratio is suppressed by the buffering by the torque converter 2.

  After the process of step S150, after waiting for a predetermined time in step S220 of FIG. 5, it is determined in step S230 whether or not the actual gear ratio hunting has been eliminated. If it is determined that the actual gear ratio hunting has not been eliminated, the process returns to step S140 in FIG. 5 and the process is repeated.

  When the determination in step S140 is performed again and it is determined that the value does not exceed the first threshold (timing t4), the lockup clutch is brought into the engaged state, and then the process proceeds to step S160 to perform the second determination process. .

  In step S160, when the second determination process is performed and it is determined that the fluctuation range of the actual gear ratio exceeds the second threshold value, the controller 12 performs the process of step S170 to increase the secondary hydraulic pressure of the secondary pulley 22. Thus, the hydraulic control circuit 11 is instructed. Thereby, the fastening force of the belt in the variator 30 is increased, the change in the actual gear ratio is suppressed, and the hunting of the actual gear ratio is suppressed.

  After the process of step S170, after waiting for a predetermined time in step S220 of FIG. 5, it is determined in step S230 whether or not the actual gear ratio hunting has been eliminated. If it is determined that the actual gear ratio hunting has not been eliminated, the process returns to step S140 in FIG. 5 and the process is repeated.

  When the determination in step S140 is performed again and it is determined that the value does not exceed the first threshold value, the process proceeds to step S160 and the second determination process is performed. If it is determined in the second determination process that the second threshold is not exceeded (timing t5), the increased secondary hydraulic pressure is decreased, and the process proceeds to step S180.

  If the third determination process is performed in step S180 and it is determined that the fluctuation range of the actual speed ratio exceeds the third threshold value, the controller 12 performs the process of step S190 and sets the feedback gain of the actual speed ratio to zero. Set. This suppresses hunting of the actual speed ratio that occurs when the actual speed ratio does not follow the target speed ratio without feeding back the deviation between the target speed ratio and the actual speed ratio.

  After the process of step S190, after waiting for a predetermined time in step S220 of FIG. 5, it is determined in step S230 whether or not the actual gear ratio hunting has been eliminated. If it is determined that the actual gear ratio hunting has not been eliminated, the process returns to step S140 in FIG. 5 and the process is repeated.

  When the determination in step S140 is performed again and it is determined that the value does not exceed the first threshold value, the process proceeds to step S160 and the second determination process is performed. If it is determined that it does not exceed the second threshold value, the process proceeds to step S180, the second determination process is performed, and if it is determined that it does not exceed the third threshold value (timing t6), it is set to zero. The returned feedback gain is returned, and the process proceeds to step S210.

  In step S210, the controller 12 sets a dead zone in which the deviation between the target speed ratio and the actual speed ratio is used for feedback of the actual speed ratio. As a result, when the deviation between the target speed ratio and the actual speed ratio is small, feedback is suppressed, so that hunting of the actual speed ratio that occurs when the actual speed ratio does not follow the target speed ratio is suppressed. When fluctuations in the actual gear ratio that are less than the smallest third threshold are predicted, setting the dead zone with the smallest bounce by control can suppress fluctuations in the actual gear ratio and reduce the bounce. it can. If the change in the actual gear ratio becomes large after setting the dead zone, one of the above-described steps S140, S160, and S180 is YES, and processing for suppressing the other changes in the actual gear ratio is performed.

  After the process of step S210, a timer for a predetermined time is started in step S220 of FIG. 5, and after the timer expires in step S221, it is determined in step S230 whether or not the actual gear ratio hunting has been eliminated (timing t7). ). If it is determined that the actual gear ratio hunting has been eliminated, the set dead zone is restored, and the process of the flowchart of FIG. 5 ends (timing t8).

  By performing such control, hunting of the actual gear ratio is prevented.

  FIG. 8 is an explanatory diagram of the first to third threshold values according to the embodiment of this invention.

  In FIG. 8, as an example, a comparison between the first to third threshold values with respect to the deviation between the target speed ratio and the actual speed ratio will be described.

  More specifically, the controller 12 acquires the absolute value of the difference between the amount of change in the target gear ratio (time change) and the amount of change in the actual gear ratio (time change) as a deviation. The obtained deviation is compared with the first threshold value in step S140 of FIG.

  The first threshold value is set to a large value compared to the second to third threshold values. When the deviation is large compared to the first threshold value, the hunting of the actual gear ratio occurring is the largest. Determine the state.

  When the deviation exceeds the first threshold value, the control having the greatest effect of suppressing the actual gear ratio hunting is executed. Specifically, the lockup clutch of the torque converter 2 is controlled to a slip state or a released state (step S150 in FIG. 5). By controlling the lock-up clutch to the slip state or the released state, hunting of the actual gear ratio is suppressed, but fuel efficiency performance and power performance are degraded. Therefore, when the deviation falls below the first threshold value by the control in step S150, the process proceeds to the next step S160, and the deviation is compared with the second threshold value.

  The second threshold value is set to a value smaller than the first threshold value but larger than the third threshold value, and it is determined whether the actual speed ratio hunting occurring is relatively large.

  In step S160, when the deviation exceeds the second threshold value, the control having the second largest effect of suppressing the actual gear ratio hunting is executed. Specifically, the secondary hydraulic pressure of the variator 20 is increased so as to increase the belt pressure (step S170 in FIG. 5). By increasing the secondary oil pressure, hunting of the actual gear ratio is suppressed, but by increasing the oil pressure, fuel efficiency is reduced. Therefore, when the deviation is smaller than the second threshold value by the control in step S170, the process proceeds to the next step S180 and the deviation is compared with the third threshold value.

  The third threshold value is smaller than the first and second threshold values and is set to a relatively small value, and it is determined whether the actual speed ratio hunting occurring is relatively small.

  In step S180 of FIG. 5, when the deviation exceeds the third threshold value, the control having the third largest effect that can suppress the actual gear ratio hunting is executed. Specifically, the feedback gain of the actual gear ratio is set to 0 and control is performed so that feedback based on the deviation is not executed (step S190 in FIG. 5). Such control can suppress hunting of the actual gear ratio due to feedback.

  When the deviation falls below the third threshold value by the control in step S190 in FIG. 5, the process proceeds to the next step S210, and the control that has the fourth largest effect of suppressing the actual gear ratio hunting is executed. Specifically, a dead zone for feedback of the actual gear ratio is set. Thus, if the deviation is within the range of the dead zone, control is performed so that feedback based on the deviation is not executed. Such control can suppress hunting of the actual gear ratio due to feedback. If it is determined after the control in step S210 in FIG. 5 that the actual gear ratio hunting has been eliminated, the processing in the flowchart in FIG. 5 ends.

  FIG. 9 is an explanatory diagram showing the relationship between the first to third threshold values and the actual gear ratio according to the embodiment of the present invention.

  In FIG. 9, the vertical axis indicates the thrust for clamping the belt by the clamping force of the primary pulley, and the horizontal axis indicates the actual gear ratio.

  The variator 20 is a belt type CVT. In the belt type CVT, the relationship between the actual transmission ratio and the thrust of the primary pulley is generally nonlinear as shown in FIG. 9, and the smaller the actual transmission ratio, the larger the required thrust to the primary pulley, and the actual transmission ratio becomes smaller. The larger the value, the smaller the required thrust to the primary pulley.

  Here, let us consider a case where the threshold value for detecting fluctuation (hunting) of the actual gear ratio is the same regardless of the magnitude of the actual gear ratio. In this case, for example, in a region where the actual gear ratio is relatively small, the change in thrust is large with respect to the change in the actual gear ratio. There is a possibility that only the processing (that is, steps S190 and S210 in FIG. 5) is executed, and effective hunting suppression control is not executed. On the other hand, in the region where the actual gear ratio is relatively large, the change in thrust is small with respect to the change in the actual gear ratio. However, even in a situation where the driver is small and does not give the driver a sense of incongruity, there is a possibility that a deterioration in fuel consumption or a shock is caused by performing the anti-hunting control.

  As described above, since the thrust changes with respect to the magnitude of the actual gear ratio, it is desirable to change the threshold value (first to third threshold values) for determining the fluctuation of the actual gear ratio in response to this. For example, when the actual speed ratio is on the small side, the first to third threshold values are set to double, and when the actual speed ratio is on the large side, the first to third threshold values are used as they are. It may be set to.

  Therefore, as shown in FIG. 9, a threshold width is set for each actual gear ratio so that the variation in thrust is substantially the same, and in the determination after step S140 in FIG. 5, the actual gear ratio at that time is set. A corresponding threshold value may be acquired, and the first to third determinations may be executed based on the acquired threshold value.

  Specifically, in a region where the actual gear ratio is relatively small, the threshold is set to be relatively large, the sensitivity to thrust fluctuation is slowed down, and fuel efficiency and driving performance are prioritized. on the other hand. In a region where the actual gear ratio is relatively large, the threshold is set relatively small, the sensitivity to the fluctuation of thrust is set high, and the hunting process is prioritized. By setting the threshold value in this way, it is possible to achieve both relaxation of shock and prevention of hunting.

  FIG. 10 is an explanatory diagram showing the relationship between the first to third threshold values and the actual gear ratio in the embodiment of the present invention, and is an explanatory diagram showing the thrust of the secondary pulley.

  In FIG. 10, the vertical axis indicates the thrust for clamping the belt by the clamping force of the secondary pulley, and the horizontal axis indicates the actual gear ratio.

  The relationship between the actual gear ratio and the thrust of the secondary pulley has a characteristic that, contrary to the primary pulley shown in FIG. 9 described above, the thrust is smaller as the actual gear ratio is lower and the thrust is larger as the actual gear ratio is larger. doing.

  As described above, since the thrust changes with respect to the magnitude of the actual gear ratio, it is desirable to change the threshold value (first to third threshold values) for determining the fluctuation of the actual gear ratio in response to this. For example, when the actual gear ratio is on the small side, the first to third threshold values are used as they are, and when the actual gear ratio is on the large side, the first to third threshold values are each set to double. Also good.

  In particular, when hunting of the actual gear ratio occurs due to fluctuations in the hydraulic pressure of the primary pulley, the threshold value is changed based on the characteristics shown in FIG. On the other hand, when the actual gear ratio hunting occurs due to a change in the hydraulic pressure of the secondary pulley, the threshold is changed based on the characteristics shown in FIG. In the case where hunting of the actual gear ratio occurs by both the primary pulley and the secondary pulley, the threshold value may be changed based on both characteristics shown in FIGS.

  By setting the threshold value in this way, it is possible to achieve both relaxation of shock and prevention of hunting.

  As described above, in the embodiment of the present invention, the winding of the power transmission belt (V belt 23) mounted on the vehicle and clamped by the hydraulic pressure supplied to the pair of pulleys (primary pulley 21 and secondary pulley 22). The control device for the transmission 4 that can change the actual transmission ratio by changing the engagement diameter, calculates the target transmission ratio based on the state of the vehicle, and indicates the instruction value so that the actual transmission ratio follows the target transmission ratio. And when the controller 12 that controls the control value of the transmission 4 is detected or estimated that the change amount of the control value per unit time is larger than the change amount of the instruction value per unit time. A gear ratio fluctuation prediction unit that predicts occurrence of a gear ratio fluctuation, and a gear ratio fluctuation suppression unit that executes control to suppress fluctuations in the actual gear ratio when fluctuations in the actual gear ratio are detected by the gear ratio fluctuation prediction And provided.

  With this configuration, when fluctuations in the actual gear ratio are predicted, control is performed so as to suppress fluctuations in the actual gear ratio, so that fluctuations in the actual gear ratio that are not intended by the driver are suppressed. Can prevent the driver from feeling uncomfortable.

  The instruction value is an instruction value of the hydraulic pressure supplied to the secondary pulley 22, and the control value is an actual hydraulic pressure supplied to the secondary pulley 22, and the gear ratio fluctuation prediction unit is supplied to the secondary pulley 22. When it is detected that the change amount per unit time of the actual hydraulic pressure is larger than the change amount per unit time of the indicated value of the hydraulic pressure supplied to the secondary pulley 22, the change in the actual gear ratio is predicted. The change of the actual gear ratio can be detected by the hydraulic pressure of the secondary pulley 22 related to the change of the actual gear ratio.

  The variator is provided with a solenoid for controlling the hydraulic pressure supplied to the secondary pulley 22, the indicated value is an indicated current value for instructing the operation of the solenoid, and the controlled value is an actual current value of the solenoid, The gear ratio fluctuation prediction unit detects that the change amount per unit time of the actual current value to the solenoid based on the control value is larger than the change amount per unit time of the indicated current value of the solenoid In addition, since the fluctuation of the actual gear ratio is detected, the fluctuation of the actual gear ratio can be detected not by the hydraulic pressure that actually changes the actual gear ratio but by the actual current value and the command current value of the solenoid. That is, by detecting a change in current for controlling the oil pressure, a change in the actual gear ratio can be detected at an earlier stage than the change in the oil pressure.

  The gear ratio fluctuation prediction unit determines that the change amount per unit time of the actual current value or the actual hydraulic pressure per unit time of the indicated current value or the indicated hydraulic pressure when the switch related to the operation of the electrical equipment provided in the vehicle is opened or closed. Therefore, it is possible to predict the occurrence of fluctuations in the actual gear ratio not by actual hydraulic pressure or current but by the operation of the switch. That is, by detecting the opening / closing operation of the switch that causes the fluctuation of the actual current value for controlling the hydraulic pressure, the occurrence of the fluctuation of the actual gear ratio can be predicted at an earlier stage than the fluctuation of the hydraulic pressure or the current. .

  The gear ratio fluctuation suppressing unit executes control for suppressing fluctuation of the actual gear ratio, detects the fluctuation width of the actual gear ratio, and detects the detected fluctuation width of the actual gear ratio and a plurality of predetermined threshold values. And, as a result of the comparison, control for suppressing fluctuations in the actual gear ratio is changed. In this way, by performing different control for each of the plurality of threshold values, it is possible to achieve both suppression of fluctuations and prevention of rebound of changes in vehicle behavior due to fluctuation suppression control.

  The speed change control unit controls the actual speed ratio to follow the target speed ratio by feeding back the deviation between the target speed ratio and the actual speed ratio to the control value. When the width is small, a dead zone is set for the deviation to be fed back, so if there is a change in the actual gear ratio, a dead zone for the change will be provided to slow down the ability to follow the change, and an instruction for shift control Variations in the actual gear ratio caused by the value can be suppressed.

  The transmission is provided with a torque converter 2, and the gear ratio fluctuation suppressing unit controls the torque converter 2 to the slip state when the fluctuation range of the actual gear ratio is large. Fluctuations can be buffered, and fluctuations in the actual gear ratio can be suppressed.

  The transmission is provided with a torque converter 2, and the gear ratio fluctuation suppression unit controls the torque converter 2 to the converter state when the fluctuation range of the actual gear ratio is large. Fluctuations can be buffered, and fluctuations in the actual gear ratio can be suppressed.

  The transmission is provided with a torque converter 2, and the gear ratio fluctuation suppressing unit controls the torque converter 2 to the converter state when the fluctuation range of the actual gear ratio is large after controlling the torque converter 2 to the slip state. The state of the torque converter can be controlled according to the fluctuation range to buffer the fluctuation of the rotational speed, and the fluctuation of the actual gear ratio can be suppressed.

  The embodiment of the present invention has been described above, but the above embodiment is merely one example of application of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. is not.

  For example, in the above embodiment, a belt type continuously variable transmission mechanism is provided as the variator 20, but the variator 20 is a continuously variable transmission mechanism in which a chain is wound around pulleys 21 and 22 instead of the belt 23. May be. Alternatively, the variator 20 may be a toroidal continuously variable transmission mechanism in which a tiltable power roller is disposed between the input disk and the output disk.

  In the above embodiment, the continuously variable transmission including the variator 20 and the auxiliary transmission mechanism 30 has been described as an example. However, the auxiliary transmission mechanism 30 may be omitted.

  Further, in the above embodiment, the actual speed ratio hunting is determined based on the actual speed ratio, but is not limited thereto, and may be determined based on the engine rotational speed Ne. That is, hunting of the engine speed Ne occurs due to hunting of the actual gear ratio. The hunting of the engine rotational speed Ne may cause, for example, an instrument panel speedometer to fluctuate, which may cause the driver to feel visually uncomfortable. Also, the actual behavior of the vehicle may fluctuate, which may cause the driver to feel uncomfortable. It is. Further, it may be determined whether or not the actual gear ratio hunting has been eliminated in step S230 of FIG. 5 based on the engine rotational speed Ne.

  This application claims priority based on Japanese Patent Application No. 2012-201357 filed with the Japan Patent Office on September 13, 2012. The entire contents of these applications are incorporated herein by reference.

Claims (10)

A control device for a continuously variable transmission mounted on a vehicle and capable of changing an actual gear ratio by changing a winding diameter of a set of pulleys and a power transmission belt clamped by hydraulic pressure supplied to the set of pulleys Because
A shift control unit that calculates a target gear ratio based on the state of the vehicle, outputs an instruction value so that an actual gear ratio follows the target gear ratio, and controls a control value of the continuously variable transmission;
Gear ratio fluctuation prediction for predicting occurrence of fluctuations in the actual gear ratio when it is detected or estimated that the amount of change in the control value per unit time is larger than the amount of change in the instruction value per unit time And
A gear ratio fluctuation suppressing unit that executes control for suppressing fluctuations in the actual gear ratio when the gear ratio fluctuation prediction unit predicts fluctuations in the actual gear ratio;
A control device for a continuously variable transmission. A control device for a continuously variable transmission according to claim 1,
The indicated value is an indicated value of the hydraulic pressure supplied to the pulley, and the control value is an actual hydraulic pressure supplied to the pulley,
The gear ratio fluctuation prediction unit detects that the amount of change per unit time of the actual hydraulic pressure supplied to the pulley is larger than the amount of change per unit time of the indicated value of the hydraulic pressure supplied to the pulley. A control device for a continuously variable transmission that predicts fluctuations in the transmission ratio. A control device for a continuously variable transmission according to claim 1 or 2,
The continuously variable transmission is provided with a solenoid for controlling the hydraulic pressure supplied to the pulley,
The indicated value is an indicated current value that instructs the operation of the solenoid, and the control value is an actual current value of the solenoid,
The gear ratio fluctuation prediction unit detects the gear ratio when the change amount of the actual current value of the solenoid per unit time is detected to be larger than the change amount of the command current value per unit time. A control device for a continuously variable transmission that predicts fluctuations. A control device for a continuously variable transmission according to any one of claims 1 to 3,
The gear ratio fluctuation prediction unit is configured to change a change amount of the control value per unit time when the switch related to the operation of the electrical equipment provided in the vehicle is opened and closed. A control device for a continuously variable transmission that estimates that the amount is larger than the amount. A control device for a continuously variable transmission according to any one of claims 1 to 4,
The gear ratio fluctuation suppressing unit is
After executing the control to suppress the fluctuation of the actual gear ratio, the fluctuation range of the actual gear ratio is detected,
A control device for a continuously variable transmission that compares a detected fluctuation range of an actual gear ratio with a plurality of predetermined threshold values, and changes control for suppressing fluctuation of the actual gear ratio as a result of the comparison. A control device for a continuously variable transmission according to claim 5,
The transmission control unit controls the deviation between the target transmission ratio and the actual transmission ratio to be fed back to the control value so that the actual transmission ratio follows the target transmission ratio;
The gear ratio fluctuation suppressing unit is a control device for a continuously variable transmission that sets a dead band in the deviation for performing the feedback when the fluctuation range of the actual gear ratio is small. A control device for a continuously variable transmission according to claim 5 or 6,
The continuously variable transmission is provided with a torque converter,
The gear ratio fluctuation suppressing unit is a control device for a continuously variable transmission that controls the torque converter to a converter state when the fluctuation range of the actual gear ratio is large. A control device for a continuously variable transmission according to any one of claims 5 to 7,
The continuously variable transmission is provided with a torque converter,
The control device for a continuously variable transmission, wherein the gear ratio fluctuation suppressing unit controls the torque converter to a slip state when a fluctuation range of the actual gear ratio is large. A control device for a continuously variable transmission according to claim 5 or 6,
The continuously variable transmission is provided with a torque converter,
The gear ratio fluctuation suppressing unit controls the torque converter to a slip state when the fluctuation range of the actual gear ratio is large,
A control device for a continuously variable transmission that controls the torque converter to a released state when fluctuations in the actual gear ratio are not suppressed after controlling the torque converter to a slip state. Method for controlling a continuously variable transmission mounted on a vehicle and capable of changing an actual gear ratio by changing a winding diameter of a set of pulleys and a power transmission belt sandwiched by hydraulic pressure supplied to the set of pulleys Because
Calculating a target gear ratio based on the state of the vehicle, outputting an instruction value so that an actual gear ratio follows the target gear ratio, and controlling a control value of the continuously variable transmission;
A procedure for predicting the occurrence of a change in the actual gear ratio when detecting or estimating that the amount of change of the control value per unit time is larger than the amount of change of the instruction value per unit time;
A procedure for executing control for suppressing fluctuations in the actual gear ratio, when fluctuations in the actual gear ratio are predicted;
A control method for a continuously variable transmission.

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