JP2011190852A - Control device of continuously variable transmission for vehicle - Google Patents

Abstract

A control device for a continuously variable transmission capable of reducing sudden shift while maintaining good shift response.
A transmission ratio control means for performing feedback control of a shift control value based on a deviation ΔN _IN between a target input rotation speed N _{IN_tgt} and an input shaft rotation speed N _IN and a feedback gain, and a predetermined start condition When the feedback is started by the control start means 208 in the control device 50 of the continuously variable transmission having the control start means 208 that starts the feedback control when it is satisfied (S2), the deviation ΔN _IN has a predetermined follow-up. If it exceeds the _performance drop determination value N _{IN_th1} (S3), the follow-up performance of the feedback control is greater than the case where the deviation ΔN _IN does not exceed the follow-up drop determination value N _{IN_th1} by the follow-up performance drop means 222 of the follow-up control means 218. (S4), the execution of sudden shift is reduced when the deviation ΔN _IN is large. It is.
[Selection] Figure 8

Description

  The present invention relates to a control device for a continuously variable transmission, and more particularly, to a control device for a continuously variable transmission that can achieve both improvement of response in shifting and reduction of shift shock.

  2. Description of the Related Art A continuously variable transmission is known in which a gear ratio that is a ratio between an input shaft rotation speed and an output shaft rotation speed can be continuously changed continuously. For example, it is a continuously variable transmission described in Patent Document 1. In such a continuously variable transmission, the gear ratio is controlled by controlling the gear ratio to be a target gear ratio set based on the running state of the vehicle such as the vehicle speed and output torque.

  In such speed ratio control, feedback control based on the deviation between the target rotational speed of the predetermined member and the actual rotational speed in the transmission can be performed. Patent Document 1 discloses, as an example of the transmission ratio control, a technique for feedback-controlling the transmission ratio based on a deviation between a target input rotational speed and an actual input rotational speed in the transmission.

JP 2001-324007 A

  By the way, when the difference between the actual speed ratio and the target speed ratio is large, in the feedback control, since the deviation becomes large, the speed ratio is greatly changed. For example, drivability is reduced. There was a possibility that the problem of deterioration would occur. In order to prevent such a problem, for example, as in the technique described in Patent Document 1, unless the vehicle is in an uphill state, a downshift due to feedback control is not experienced as a shock, or the vehicle There has been proposed a method of executing feedback control when the vehicle speed is at a level that does not impair drivability. Also, in the variable pressure control of a continuously variable transmission, the response of the control target (system) is fast, and it is necessary to consider the stability of the system against hunting when setting the feedback gain, while reducing the feedback gain. Then, there is a problem that it takes time to complete the shift.

  The present invention has been made in the background of the above circumstances, and an object of the present invention is to provide a control device for a continuously variable transmission that can reduce sudden shift while maintaining good shift response. It is in.

  In order to achieve this object, the invention according to claim 1 is: (a) transmission ratio control for performing feedback control so that the deviation is eliminated based on the deviation between the target transmission ratio and the actual transmission ratio and the feedback gain. And a control device for a vehicle continuously variable transmission for starting the feedback control when a predetermined start condition is satisfied. (C) Feedback is started by the control start means. When the deviation is greater than a predetermined determination value, the apparatus further includes a follow-up control unit that lowers the follow-up performance of the feedback control as compared with the case where the deviation does not exceed the determination value. To do.

  According to a second aspect of the invention, in the control device for a continuously variable transmission for a vehicle according to the first aspect of the invention, the follow-up control means lowers the follow-up by reducing the feedback gain. To do.

  According to a third aspect of the present invention, in the control device for a continuously variable transmission for a vehicle according to the first or second aspect, the predetermined start condition is after the completion of the garage shift.

  According to a fourth aspect of the present invention, in the control device for a continuously variable transmission for a vehicle according to the first or second aspect, the predetermined start condition is after the return from the neutral control.

  According to a fifth aspect of the present invention, in the control device for a continuously variable transmission for a vehicle according to the first or second aspect, the continuously variable transmission is wound around a pair of pulleys having a variable groove width and the pair of pulleys. A belt type continuously variable transmission in which power is transmitted between an input shaft and an output shaft by a transmission belt. The predetermined start condition is that the transmission belt in the continuously variable transmission returns to a predetermined position after the vehicle is stopped. It is characterized by not being.

  According to a sixth aspect of the present invention, in the control device for a continuously variable transmission for a vehicle according to any one of the first to fifth aspects, the follow-up control means is configured so that the deviation is less than a predetermined end determination value. The follow-up performance of the feedback is restored.

  According to the first aspect of the present invention, in order to achieve the above object, the first aspect of the present invention eliminates the deviation based on (a) the deviation between the target speed ratio and the actual speed ratio and the feedback gain. In a control device for a continuously variable transmission for a vehicle, comprising: a transmission ratio control means for performing feedback control; and (b) a control start means for starting the feedback control when a predetermined start condition is satisfied. ) When the feedback is started by the control start means and the deviation exceeds a predetermined determination value, the follow-up performance of the feedback control is greater than the case where the deviation does not exceed the determination value by the follow-up control means. Therefore, when the deviation is large, the execution of sudden shift is reduced.

  According to the second aspect of the present invention, the follow-up control means lowers the follow-up performance by reducing the feedback gain, so that the execution of the sudden shift can be suitably reduced.

  According to the third aspect of the present invention, since the predetermined start condition is after the completion of the garage shift, the feedback control is executed based on the end of the garage shift. This eliminates the need for an input shaft rotation speed sensor or the like of the continuously variable transmission. Moreover, the precision of components, such as a continuously variable transmission, can be eased.

  According to the fourth aspect of the present invention, since the predetermined start condition is after the return from the neutral control, the feedback control is executed based on the end of the neutral control. This eliminates the need for an input shaft rotation speed sensor or the like of the continuously variable transmission. Moreover, the precision of components, such as a continuously variable transmission, can be eased.

  According to the fifth aspect of the present invention, since the predetermined start condition is that the transmission belt in the continuously variable transmission has not returned to the predetermined position after the vehicle stops, the feedback control is performed after the vehicle suddenly stops. Executed. This eliminates the need for an input shaft rotation speed sensor or the like of the continuously variable transmission. Further, even when the transmission belt has not returned to the predetermined position after the sudden stop, the execution of the sudden shift can be suitably reduced.

  According to the invention of claim 6, the follow-up control means restores the feedback follow-up when the deviation falls below a predetermined end determination value. The responsiveness can be improved when the vehicle is in a traveling state with less risk of sudden shift. In other words, only in a traveling state where there is a risk of sudden gear change, the follow-up property is lowered so as to reduce the sudden gear shift, so that both the follow-up property to the gear shift and the reduction of the sudden gear change are compatible.

1 is a skeleton diagram illustrating a configuration of a vehicle power transmission device to which the present invention is applied. It is a block diagram explaining the principal part of the control system provided in the vehicle in order to control the vehicle drive device etc. of FIG. FIG. 2 is a hydraulic circuit diagram showing a main part related to hydraulic control related to shift control of a continuously variable transmission, among hydraulic control circuits for controlling the vehicle power transmission device of FIG. 1. FIG. 5 is a relationship diagram (map, region diagram) showing a lockup clutch disengagement region (lockup off), a slip control region, and an engagement region (lockup on), with the throttle valve opening and the vehicle speed as variables. It is a functional block diagram explaining the principal part of the control function by the electronic controller of FIG. FIG. 6 is a diagram illustrating an example of an automatic transmission map for obtaining an input-side target rotational speed in accordance with an operating state when automatic transmission control is performed by the transmission ratio control unit of FIG. 5. It is a flowchart for demonstrating the principal part of the control action of the electronic controller in a present Example. It is a time chart explaining the state of a vehicle when garage control is performed and the feedback control of the gear ratio of a continuously variable transmission is performed after the completion | finish. It is a figure explaining the other aspect of the followability decreasing means in an Example, Comprising: It is a figure explaining the relationship of the deviation and gain which are referred when setting by a followability reducing means.

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

  FIG. 1 is a skeleton diagram illustrating the configuration of a vehicle power transmission device 10 to which the present invention is applied. This vehicle power transmission device 10 is a horizontal automatic transmission, which is preferably employed in an FF (front engine / front drive) type vehicle, and includes an engine 12 as a driving power source. . The output of the engine 12 constituted by an internal combustion engine is the crankshaft of the engine 12, the torque converter 14 as a fluid transmission device, the forward / reverse switching device 16, the belt type continuously variable transmission (CVT) 18, the reduction gear. It is transmitted to the differential gear device 22 via the device 20 and distributed to the left and right drive wheels 24L, 24R.

  The torque converter 14 includes a pump impeller 14p connected to the crankshaft of the engine 12 and a turbine impeller 14t connected to the forward / reverse switching device 16 via a turbine shaft 34 corresponding to an output side member of the torque converter 14. And power transmission is performed via a fluid. Further, a lockup clutch 26 is provided between the pump impeller 14p and the turbine impeller 14t, and the engagement side oil is provided by a lockup control valve 106 in the hydraulic control circuit 100 (see FIG. 3). The hydraulic pressure supply to the chamber and the open side oil chamber is switched to engage or release, and the pump impeller 14p and the turbine impeller 14t are integrally rotated by being completely engaged. Also connected to the pump impeller 14p is a mechanical oil pump 28 that generates hydraulic pressure for performing the shift control of the continuously variable transmission 18, the belt clamping pressure control, the engagement release control of the lockup clutch 26, and the like. It is operated in conjunction with engine rotation.

  The forward / reverse switching device 16 is composed mainly of a forward clutch C1 and a reverse brake B1 and a double pinion type planetary gear device 16p, and the turbine shaft 34 of the torque converter 14 is integrally connected to the sun gear 16s. The input shaft 36 of the continuously variable transmission 18 is integrally connected to the carrier 16c, while the carrier 16c and the sun gear 16s are selectively connected via the forward clutch C1, and the ring gear 16r is connected to the reverse brake B1. And is fixed to the housing selectively. Both the forward clutch C1 and the reverse brake B1 are hydraulic friction engagement devices that are frictionally engaged by a hydraulic actuator. The forward clutch C1 and the reverse brake B1 correspond to the travel clutch of the present invention.

  When the forward clutch C1 is engaged and the reverse brake B1 is released, the forward / reverse switching device 16 is brought into an integrally rotating state, whereby the turbine shaft 34 is directly connected to the input shaft 36, and the forward drive power is increased. The transmission path is established (achieved), and the driving force in the forward direction is transmitted to the continuously variable transmission 18 side. When the reverse brake B1 is engaged and the forward clutch C1 is released, the forward / reverse switching device 16 establishes (achieves) the reverse power transmission path, and the input shaft 36 is connected to the turbine shaft 34. On the other hand, it is rotated in the opposite direction, and the driving force in the reverse direction is transmitted to the continuously variable transmission 18 side. When both the forward clutch C1 and the reverse brake B1 are released, the forward / reverse switching device 16 enters a neutral state (power transmission cut-off state) in which power transmission is cut off.

  The continuously variable transmission 18 is an input side member provided on the input shaft 36, a drive side pulley (primary pulley, primary sheave) 42 having a variable effective diameter, and an output side member provided on the output shaft 44. A driven pulley (secondary pulley, secondary sheave) 46 having a variable diameter and a transmission belt 48 wound around these variable pulleys 42, 46, and the variable pulleys 42, 46 and the transmission belt 48 are provided. Power is transmitted via the frictional force between them.

The variable pulleys 42 and 46 are fixed rotation bodies 42 a and 46 a fixed to the input shaft 36 and the output shaft 44, respectively, and are not rotatable relative to the input shaft 36 and the output shaft 44 and are movable in the axial direction. Driven hydraulic actuator (primary pulley side hydraulic actuator) 42c and driven side hydraulic actuator (secondary pulley side) as hydraulic actuators that apply thrust to change the V-groove width between the movable rotors 42b and 46b provided The hydraulic oil pressure to the drive side hydraulic actuator 42c is controlled by the hydraulic pressure control circuit 100, so that the V groove widths of the variable pulleys 42 and 46 are changed. The engagement diameter (effective diameter) of the transmission belt 48 is changed, and the gear ratio γ (= input shaft) Rolling speed _{N IN} / output shaft speed _{N OUT)} is continuously changed.

  FIG. 2 is a block diagram illustrating a main part of a control system provided in the vehicle for controlling the vehicle power transmission device 10 and the like of FIG. The electronic control unit 50 includes, for example, a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM and follows a program stored in the ROM in advance. By performing signal processing, output control of the engine 12, shift control of the continuously variable transmission 18, belt clamping pressure control, torque capacity control of the lockup clutch 26, and the like are executed. This is divided into control and hydraulic control for the continuously variable transmission 18 and the lockup clutch 26.

The electronic control unit 50 includes a signal representing the crankshaft rotational speed corresponding to the crankshaft rotational angle (position) A _CR (°) detected by the engine rotational speed sensor 52 and the rotational speed (engine rotational speed) Ne of the engine 12. , A signal representing the rotational speed (turbine rotational speed) Nt of the turbine shaft 34 detected by the turbine rotational speed sensor 54, and the output rotational speed of the continuously variable transmission 18 detected by the vehicle speed sensor (output shaft rotational speed sensor) 58. A rotation speed (output shaft rotation speed) N _{OUT of a} certain output shaft 44, that is, a vehicle speed signal indicating a vehicle speed V corresponding to the output shaft rotation speed Nout, and an intake pipe 32 (see FIG. 1) of the engine 12 detected by the throttle sensor 60 throttle valve opening degree signal representing the throttle valve opening theta _TH of the electronic throttle valve 30 provided, detection by the coolant temperature sensor 62 Is a signal representing the cooling water temperature T _W of the engine 12, a signal representative of the oil temperature T _CVT of a hydraulic circuit of the continuously variable such as transmission 18 detected by the CVT oil temperature sensor 64, an accelerator detected by the accelerator opening sensor 66 An accelerator opening signal indicating the accelerator opening Acc that is the operation amount of the pedal 68, a brake operation signal indicating whether or not the foot brake that is a service brake is operated B _ON detected by the foot brake switch 70, and a lever position sensor 72 and a lever position (operating position) of a shift lever 74 operated position signal representative of the P _SH, and the belt narrow pressure signal representative of the belt Sema圧Pd of the driven side hydraulic actuator 46c to be detected is supplied by the oil pressure sensor 75.

Further, the electronic control unit 50 receives an engine output control command signal S _E for controlling the output of the engine 12, for example, a throttle signal for driving a throttle actuator 76 for controlling the opening / closing of the electronic throttle valve 30 and a fuel injection device 78. An injection signal for controlling the amount of fuel injected from the engine, an ignition timing signal for controlling the ignition timing of the engine 12 by the ignition device 80, and the like are output. Further, a shift control command signal S _T for changing the transmission gear ratio γ of the continuously variable transmission 18, a clamping pressure control command signal S _B for adjusting the clamping pressure of the transmission belt 48, engagement of the lockup clutch 26, Lock-up control command signal S _{L / U} for controlling the opening and slipping amount, for example, a command signal or lock-up for driving a solenoid valve to be described later for switching the valve position of the lock-up relay valve in the hydraulic control circuit 100 A command signal for driving a linear solenoid valve for adjusting the engagement force of the clutch 26, a signal for releasing or half-engaging the forward clutch C1 or the reverse brake B1 at the neutral control, and a forward clutch at the garage shift A signal for adjusting the engagement pressure of C1 or the reverse brake B1 is output to the hydraulic control circuit 100. It is.

  The shift lever 74 is, for example, one of five lever positions “P”, “R”, “N”, “D”, and “L” that are arranged in the vicinity of the driver's seat and sequentially positioned. To be manually operated.

  The “P” position (range) is a neutral state (neutral state) in which the power transmission path of the vehicle power transmission device 10 is opened, that is, the power transmission of the vehicle power transmission device 10 is interrupted, and is mechanically performed by a mechanical parking mechanism. It is a parking position (position) for preventing (locking) the rotation of the output shaft 44, and the “R” position is a reverse travel position (position) for reversing the rotation direction of the output shaft 44, and “N The "" position is a neutral position (position) for setting the neutral state in which the power transmission of the vehicle power transmission device 10 is interrupted, and the "D" position is an automatic shift within the shift range that allows the continuously variable transmission 18 to shift. This is the forward travel position (position) where the mode is established and automatic shift control is executed. An engine braking position is caused to use (position). As described above, the “P” position and the “N” position are non-traveling positions that are selected when the power transmission path is in the neutral state and the vehicle is not traveling, and the “R” position, the “D” position, and the “L” position. Is a travel position that is selected when the vehicle travels with the power transmission path in a power transmission enabled state that enables power transmission through the power transmission path.

FIG. 3 shows the hydraulic pressure of the hydraulic pressure control circuit 100 that is relevant to the lockup control of the lockup clutch 26 and the engagement hydraulic pressure control of the forward clutch C1 and the reverse brake B1 in accordance with the operation of the shift lever 74. It is a circuit diagram. 3, the hydraulic control circuit 100 includes a first switching valve SL1 for outputting a switching pressure PSL1 as source pressure modulator pressure P _SM supplied from a not-shown pressure regulating valve, the modulator pressure P _SM supplied from a not-shown pressure regulating valve Is a second switching valve SL2 that outputs a switching pressure PSL2 using the original pressure as a source pressure, and a clutch that switches hydraulic oil supplied to the forward clutch C1 and the reverse brake B1 according to the output states of the first switching valve SL1 and the second switching valve SL2. A release side position (off-side position) where the lock-up clutch 26 is opened according to the output states of the apply control valve 102, the first switching valve SL1 and the second switching valve SL2, and a state where the lock-up clutch 26 is engaged. Lock-up relay that can be switched to either one position (ON position) Lube 104, the linear solenoid valve SLU for outputting a control pressure P _SLU corresponding to a driving current supplied from the electronic control unit 50, control of the linear solenoid valve SLU by the lock-up relay valve 104 is switched to the engagement side position According to the operation of the shift lever 74, the lockup control valve 106 for controlling the engagement force of the lockup clutch 26 according to the pressure P _SLU , the forward clutch C1 and the reverse brake B1 are selectively engaged or released. A manual valve 108 for switching the path mechanically, an SLU damper 110 for absorbing pulsation of the control pressure P _SLU of the linear solenoid valve SLU, and the like are provided.

The clutch apply control valve 102 functions as a switching valve for switching the supply state of hydraulic oil supplied to the forward clutch C1 and the reverse brake B1 via the manual valve 108. When the clutch apply control valve 102 is moved in the axial direction, the hydraulic oil supplied to the forward clutch C1 and the reverse brake B1 is set to a normal modulator pressure LPM2 regulated by a pressure regulating valve (not shown). (The left side in the figure), the hydraulic oil supplied to the forward clutch C1 and the reverse brake B1 is positioned at any of the fail / garage positions (the right side in the figure) where the control pressure P _SLU of the linear solenoid valve SLU is used. A spool valve element 120, a first input port 122 to which a constant modulator pressure LPM2 regulated by a pressure regulating valve (not shown) is inputted, a second input port 124 to which a control pressure PSLU of the linear solenoid valve SLU is inputted, A spool valve connected to the input port 150 of the manual valve 108 A first output port 126 communicated with either the first input port 122 or the second input port 124 according to the switching position, and a third input to which a control pressure LPM3 regulated by a pressure regulating valve (not shown) is inputted. The third input port 128 and the fourth input port 130 are connected to the port 128, the fourth input port 130 to which the hydraulic pressure Pd of the driven hydraulic actuator 46c is input, and the driving hydraulic actuator 42c. A second output port 132 communicated with any one of the input ports 130, a spring 134 that constantly biases the spool valve element 120 to the normal position side, and a thrust toward the fail / garage position side to the spool valve element 120 In order to apply an oil chamber 136 that receives the switching pressure _PSL1 to the spool valve element 120 and a thrust toward the normal position side And an oil chamber 138 for receiving the switching pressure _PSL2 .

For example, is switched pressure P _SL1 of the first switching valve SL1 is when it is supplied to the oil chamber 136, the spool valve element 120 is Ko' the urging force of the spring 134 is moved to the fail / garage position side (right side in the drawing) . At this time, the second input port 124 and the first output port 126 are communicated, and the control pressure P _SLU of the linear solenoid valve SLU is supplied to the input port 150 of the manual valve 108. That is, the control pressure P _SLU of the linear solenoid valve SLU is engaging pressure of the forward clutch C1. Since the control pressure P _SLU is changed linearly based on the duty ratio of the exciting current of the linear solenoid valve SLU, the forward clutch C1 is applied during the garage shift which is the engagement process of the forward clutch C1. The engagement hydraulic pressure can be changed, and the engagement shock can be reduced. Further, the fourth input port 130 and the second output port 132 are communicated with each other, and the hydraulic pressure Pd of the driven hydraulic actuator 46c is supplied to the driving hydraulic actuator 42c.

  On the other hand, when the switching pressure PSL2 of the second switching valve SL2 is supplied to the oil chamber 138, the spool valve element 120 is moved to the normal position side (left side in the figure). At this time, the first input port 122 and the first output port 126 are communicated, and the modulator pressure LPM2 is supplied to the input port 150 of the manual valve 108. Further, the third input port 128 and the second output port 132 are communicated with each other, and the control pressure LPM3 is supplied to the drive side hydraulic actuator 42c. That is, the modulator pressure LPM2 becomes the engagement hydraulic pressure of the forward clutch C1. Since the modulator pressure LPM2 is a constant pressure, the engaged state can be stably maintained after the engagement of the forward clutch C1 is completed.

  In the manual valve 108, the engagement port Pa (control pressure PSLU or modulator pressure LPM2) output from the first output port 126 of the clutch apply control valve 102 is supplied to the input port 150. When the shift lever 74 is operated to the “D” position or the “L” position, the engagement hydraulic pressure Pa is supplied to the forward clutch C1 via the forward output port 152, and the forward clutch C1 is engaged. . When the shift lever 74 is operated to the “R” position, the engagement hydraulic pressure Pa is supplied to the reverse brake B1 via the reverse output port 154, and the reverse brake B1 is engaged. Further, when the shift lever 74 is operated to the “P” position and the “N” position, the oil passage from the input port 150 to the forward output port 152 and the reverse output port 154 are both blocked, and the forward clutch C1. The reverse brake B1 is released.

  The lock-up clutch 26 of the torque converter 14 has a hydraulic pressure Pon in the engagement side oil chamber 162 supplied via the engagement side oil passage 160 and a release side oil chamber 166 supplied via the release side oil passage 164. This is a hydraulic friction clutch that is frictionally engaged with the front cover 168 by a differential pressure ΔP (= Pon−Poff) with respect to the hydraulic pressure Poff. The operating condition of the torque converter 14 is, for example, a so-called lockup-off in which the differential pressure ΔP is negative and the lockup clutch 26 is released, and the differential pressure ΔP is zero or more and the lockup clutch 26 is half-engaged. The so-called slip state and the so-called lock-up on, in which the differential pressure ΔP is set to the maximum value and the lock-up clutch 26 is completely engaged, are roughly classified. Further, in the slip state of the lock-up clutch 26, since the differential pressure ΔP is set to zero, the torque sharing of the lock-up clutch 26 is lost, and the torque converter 14 is brought into an operation state similar to the lock-up off.

  The lockup relay valve 104 includes a spool valve element 170 that switches between an engagement position (ON position: right side in the figure) and an open position (OFF position: left side in the figure) of the lockup clutch 26, and one of the spool valve elements 170. A spring 172 provided on the shaft end side for applying a thrust toward the open position (OFF position) to the spool valve element 170, and a first switching valve SL1 for moving the spool valve element 170 to the open position (OFF position) An oil chamber 174 that receives the switching pressure PSL1 of the second valve, an oil chamber 176 that receives the switching pressure PSL2 of the second switching valve SL2 for moving the spool valve element 170 to the engagement position (ON position) side, and a second regulator (not shown). An input port 178 to which a secondary pressure Psec regulated by a valve is input, and a lock-up control bar A bypass port 180 communicated with the control port 202 of the hub 106, an engagement side port 182 communicated with the engagement side oil passage 160, and an open side port 184 communicated with the open side oil passage 164. I have.

The lock-up control valve 106 is a spool valve element 190 for switching between a slip position (SLIP position) where the lock-up clutch 26 is in a half-engaged state and a fully engaged position (ON position) where the lock-up clutch 26 is in a fully engaged state. A spring 192 for applying a thrust force toward the slip position (SLIP position) to the spool valve element 190, and an engagement side oil of the torque converter 14 to urge the spool valve element 190 toward the slip side position. An oil chamber 194 that receives the hydraulic pressure Pon in the chamber 162 and the hydraulic pressure Poff in the open-side oil chamber 166 of the torque converter 14 to urge the spool valve element 190 toward the fully engaged position (ON position). receiving an oil chamber 196, the control pressure P _SLU for biasing toward the spool 190 to the fully engaged position An oil chamber 198, an input port 200 of the secondary pressure Psec is input, and a control port 202 which communicates with the bypass port 180 of the lockup relay valve 104 includes.

The lockup relay valve 104 and the lockup control valve 106 configured as described above switch the operating oil pressure supply state to the engagement side oil chamber 140 and the release side oil chamber 144, and the operation state of the lockup clutch 26 is changed. Can be switched. More specifically, as shown in FIG. 4, for example, the electronic control unit 50 uses the throttle valve opening θ _TH and the vehicle speed V as variables to release (lock-up off) region, slip control region, engagement (lock-up on ) Lock-up for controlling the switching of the operation state of the lock-up clutch 26 based on the actual vehicle state, for example, the throttle valve opening θ _TH and the vehicle speed V, from the previously stored relationship (map, lock-up region diagram) having the region) The clutch control means is functionally provided, and the operating state of the lockup clutch 26 is switched based on this relationship.

First, the case where the lockup clutch 26 is switched from the slip state including the released state to the lockup on state will be described. In the lock-up relay valve 104, a secondary switching pressure P _SL2 of the second switching valve SL2 is supplied to the oil chamber 176 spool 170 is moved to the engaged position (ON position), supplied to the input port 178 The pressure Psec is supplied from the engagement side port 182 through the engagement side oil passage 160 to the engagement side oil chamber 162. The secondary pressure Psec supplied to the engagement side oil chamber 162 becomes the hydraulic pressure Pon. At the same time, the open side oil chamber 166 passes through the open side oil passage 164 and communicates from the open side port 184 to the control port 202 of the lockup control valve 106 via the bypass port 180. Then, as the hydraulic pressure Poff in the open side oil chamber 166 is adjusted by the lockup control valve 106, the differential pressure ΔP (= Pon−Poff) is adjusted, and the operating state of the lockup clutch 26 changes from the slip state to the lockup on. It can be switched within the range.

Specifically, when the spool valve element 170 of the lockup relay valve 104 is urged to the engagement position (ON position), that is, when the lockup clutch 26 is switched to the engagement side state, the lock is released. In the up control valve 106, the control pressure P _SLU for urging the spool valve element 190 to the fully engaged position (ON position) is not supplied to the oil chamber 198, and the spool valve element 190 is slipped by the thrust of the spring 192. When set to (SLIP position), the secondary pressure Psec supplied to the input port 200 is supplied from the control port 202 via the bypass port 180 to the open side oil chamber 164 from the open side port 184 through the open side oil passage 142. . As a result, since the hydraulic pressure Pon and the hydraulic pressure Poff are the same pressure, even if the differential pressure ΔP is zero and the lockup relay valve 104 is switched to the engaged position, the lockup clutch 26 is The state is equivalent to lock-up off.

Further, when the spool valve element 170 of the lockup relay valve 104 is biased to the engagement position (ON position), the spool valve element 190 is moved to the complete engagement position (ON position) in the lockup control valve 106. When a predetermined control pressure P _SLU for energizing is supplied to the oil chamber 198 (at the time of lock-up on) and the spool valve element 190 is energized to the fully engaged position, the input port 200 controls the control port. The oil passage to 202 is blocked, the secondary pressure Psec is not supplied to the release side oil chamber 166, and the working oil in the open side oil chamber 166 is discharged from the drain port EX via the control port 202. As a result, since the hydraulic pressure Poff is set to zero, the differential pressure ΔP is maximized and the lockup clutch 26 is turned on.

Further, when the spool valve element 170 of the lock-up relay valve 104 is biased to the engagement position (ON position), the spool valve element 190 is completely engaged with the slip position (SLIP position) in the lock-up control valve 106. Predetermined control pressure PSLU for positioning to a position between the matching position (ON position) Is supplied to the oil chamber 198, the secondary pressure Psec supplied to the input port 200 is supplied to the open side oil chamber 166 via the control port 202, and the working oil in the open side oil chamber 166 is supplied to the control port 202. And the state of being discharged from the drain port EX is adjusted based on the control pressure P _SLU . That is, the hydraulic pressure Poff is controlled based on the control pressure P _SLU so that the rotational speed difference N _SLP (Ne−Nt) of the lock-up clutch 26 becomes the differential pressure ΔP that becomes the target rotational speed difference N _SLP ^*. The pressure is adjusted by 106.

Next, a case where the lockup clutch 26 is switched to the released state will be described. In the lockup relay valve 104, when the switching pressure _PSL2 is not supplied to the oil chamber 176 and the switching pressure _PSL1 is supplied to the oil chamber 174, the spool valve element 170 is urged by the switching pressure _PSL1 and the biasing force of the spring 172. Is moved to the open position (OFF position), and the secondary pressure Psec supplied to the input port 178 passes through the open side oil passage 164 of the torque converter 14 from the open side port 184 and is supplied to the open side oil chamber 166. The hydraulic fluid discharged through the engagement side oil chamber 162 through the engagement side oil passage 160 of the torque converter 14 and discharged to the engagement side port 182 is supplied from the discharge port 204 to the lubrication circuit 206. As a result, the differential pressure ΔP is made negative, and the lockup clutch 26 is locked up.

Here, in the hydraulic control circuit 100, as described above, the control pressure P _SLU of the linear solenoid valve SLU controls the differential pressure ΔP of the lockup clutch 26 and is supplied to the forward clutch C1 and the reverse brake B1. Used to control the engagement pressure. More specifically, when the switching pressure P _SL1 is output from the first switching valve SL1, while the switching pressure P _SL2 is not output from the second switching valve SL2, the spool valve element 120 in the clutch apply control valve 102 is Moved to fail / garage position. Note that the fail / garage position is implemented when a failure occurs in the vehicle or when the shift lever 74 is switched from the “N” position to any of the “D”, “R”, and “L” positions. In this state, the control pressure P _SLU of the linear solenoid valve SLU is supplied from the second input port 124 to the input port 150 of the manual valve 108 via the first output port 126. Then, the control pressure P _SLU is supplied to one of the forward clutch C1 and the reverse brake B1, and the forward clutch C1 or the reverse brake B1 is smoothly engaged based on the control pressure P _SLU . Further, the hydraulic pressure Pd of the driven hydraulic actuator 46c is supplied to the driving hydraulic actuator 42c, so that the transmission gear ratio γa is adjusted in advance. An orifice 208 is provided in the oil path from the output port 132 of the clutch apply control valve 102 to the drive side hydraulic actuator 42 of the variable pulley 42. The speed ratio γa is determined by the thrust ratio between the hydraulic pressure Pin to the driving hydraulic actuator 42 determined by the diameter of the orifice and the hydraulic pressure Pd of the driven hydraulic actuator 46d.

At this time, since the lock-up relay valve 104 in accordance with the switching pressure P _SL1 of the first switching valve SL1 is supplied to the oil chamber 174, spool 170 is switched to the open position (OFF position), the lock-up relay The bypass port 180 of the valve 104 is blocked. Therefore, the lockup relay valve 104 and the lockup control valve 106 are shut off, and even if the control pressure P _SLU of the linear solenoid valve SLU is supplied to the oil chamber 198, the lockup clutch 26 is not affected. . From the above, in the state where the switching pressure P _SL1 is output from the first switching valve SL1, the control pressure P _SLU of the linear solenoid valve SLU becomes the engagement pressure of the forward clutch C1 and the reverse brake B1.

Meanwhile, while the switching pressure P _SL1 from the first switching valve SL1 is not output, in the state where the switching pressure PSL2 is output from the second switching valve SL2, the lock-up relay valve 104, the spool valve element 170 is engaged position (ON Position) side. In this state, as described above, when the control pressure P _SLU of the linear solenoid valve _SLU is supplied to the oil chamber 198 of the lockup control valve 106, the spool valve element 190 is controlled in the range from the SLIP position to the ON position. The engagement state (slip state) of the lockup clutch 26 is controlled. At this time, in the clutch apply control valve 102, since the switching pressure _PSL2 is supplied to the oil chamber 138, the spool valve element 120 is positioned at the normal position, so the control pressure P _SLU of the linear solenoid valve _SLU is supplied. The second input port 124 is cut off. From the above, in a state where the switching pressure P _SL2 is output from the second switching valve SL2, the control pressure P _SLU of the linear solenoid valve SLU functions as a control pressure for controlling the engagement state of the lockup clutch 26.

  FIG. 5 is a functional block diagram for explaining the main part of the control function by the electronic control unit 50. That is, the electronic control unit 50 corresponds to the control device for a continuously variable transmission for a vehicle according to the present invention. In the functional block diagram shown in FIG. 5, means relating to control operations such as the start of feedback control and control of follow-up in feedback gain are mainly described. For example, a belt for controlling the narrow pressure of the transmission belt 48 Narrow pressure control means and the like are omitted. The electronic control unit 50 functionally includes a garage control unit 224, a neutral control unit 226, a sudden stop determination unit 228, a control start unit 208, a transmission ratio control unit 210, a target rotation speed setting unit 216, a followability control unit 218, and the like. It is configured to include.

In the following description of this embodiment, that is, in this embodiment, the input shaft rotational speed _NIN and its deviation are used as control indices in the control of the continuously variable transmission 18. However, the input shaft rotational speed N _IN is a value that has a one-to-one correspondence with the speed ratio γ of the continuously variable transmission 18 under a certain output shaft rotational speed N _OUT (or vehicle speed V). Similar control can be performed using the speed ratio γ and its deviation instead of the shaft rotational speed N _IN and its deviation.

Of these, the garage control means 224 performs so-called garage control (garage shift). Specifically, in the process of engaging the forward clutch C1 or the reverse brake B1, the hydraulic control circuit 100 performs hydraulic control such that the spool valve element 120 of the clutch apply control valve 102 is positioned on the fail / garage side. Thus, the control pressure P _SLU of the linear solenoid valve SLU is set to the engagement hydraulic pressure of the forward clutch C1. By controlling pressure P _SLU of the linear solenoid valve SLU is changed linearly, the engagement of the forward clutch C1 or the reverse brake B1 is smoothly performed. Information about whether the garage control means 224 is performing garage control or whether the garage control has been completed is supplied to the control start means 208 described later.

The neutral control means 226 performs so-called neutral control. Specifically, for example, has stopped the vehicle, when a predetermined condition such as the service brakes are actuated by the brake operation signal is fulfilled, the lever position P _SH of the shift lever 74 is in the "D" position In some cases, the forward clutch C1 is controlled to be in a half-engaged state or a released state. Further, in a case where the predetermined condition is satisfied, when the lever position P _SH of the shift lever 74 is "R" position, control is performed to the reverse brake B1 and the half-engaged state or released state. Information about whether or not the neutral control means 226 is performing neutral control is supplied to the control start means 208 described later. In this embodiment, when the neutral control by the neutral control means 226 is ended, the forward clutch C1 or the reverse brake B1 that has been half-engaged or released by the neutral control is returned to the engaged state. This includes the end of return control from control.

  The sudden stop determination means 228 determines whether or not the vehicle has been stopped in the belt type continuously variable transmission 18 such that the transmission belt 48 does not return to a predetermined position. In the belt type continuously variable transmission 18, when the vehicle decelerates and stops, the V-groove widths of the variable pulleys 42 and 46 are generally changed so that the speed ratio γ decreases as the vehicle speed decreases. The transmission belt 48 is wound around the variable pulleys 42 and 46. When the vehicle is stopped, a gear ratio for a predetermined start, for example, the lowest gear ratio is set in preparation for the next start. However, when the vehicle suddenly stops, there is a possibility that the change in the gear ratio is not in time, and the gear ratio for the start is not reached when starting after the sudden stop. Such a case corresponds to a stop that does not return to the predetermined position of the present invention. That is, the predetermined position of the belt in the present invention corresponds to the position of the transmission belt 48 that realizes the speed ratio for starting. When the vehicle stops, the sudden stop determination means 228 detects the speed ratio γ of the continuously variable transmission 18 based on, for example, the command pressure to the primary sheave 42c in the hydraulic control circuit 100, and shifts for the start. Based on whether or not the ratio is reached, it is determined whether or not a sudden stop has occurred so that the belt does not return to a predetermined position. Specifically, when the vehicle is stopped and the speed ratio for starting is not reached, it is determined that the vehicle has stopped so suddenly that the belt does not return to a predetermined position.

The control start means 208 starts feedback control of the speed ratio γ of the continuously variable transmission 18 by the speed ratio control means 210 described later when a predetermined condition is satisfied. In the present embodiment, the predetermined condition is that the execution of the garage control by the garage control means 224 is completed, the neutral control by the neutral control means 226 is completed, or the transmission belt 48 is moved by the sudden stop determination means 228. This corresponds to the establishment of at least one of starting the vehicle when it is determined that the vehicle does not return to the predetermined position. In any of these cases, when the control start means 208 is to start feedback control of the speed ratio γ of the continuously variable transmission 18, the continuously variable speed ratio 18 does not depend on the speed ratio control means 210 of the present invention. When feedback control of the input rotational speed N _IN is performed, the target input rotational speed N _{IN_tgt} corresponding to the target speed ratio γ _tgt and the input rotational speed corresponding to the actual speed ratio γ are such that sudden shift occurs. This corresponds to a case where the magnitude of the deviation ΔN _{IN from} N _IN is open.

As described above, the execution of the garage control by the garage control unit 224 is completed, the neutral control by the neutral control unit 226 is completed, or the transmission belt 48 is not returned to the predetermined position by the sudden stop determination unit 228. the vehicle when it is determined to start, the if at least one is established, in other words, the input shaft rotational speed N _iN of the turbine speed N _T and the continuously variable transmission 18 of the torque converter 14 the same In the case where it can be considered, the control start means 208 starts the feedback control by the gear ratio control means 210. Therefore, the turbine rotation speed _NT detected by the turbine rotation speed sensor 54 can be used instead of the input shaft rotation speed N _IN of the continuously variable transmission 18. In the garage control by the garage control means 224 and the return from the neutral control by the neutral control means 226, the control of the transmission ratio of the continuously variable transmission 18 is, for example, a control command in which the engagement of the forward clutch C1 is determined in advance. it is possible to control on the basis of such time variation of the value is performed by the feed forward control is performed, it is not necessary to know the input shaft rotational speed N _iN of the continuously variable transmission 18 is in such control. Therefore, it is possible to omit the installation of the input rotation speed sensor 52 for detecting an input shaft rotational speed N _IN of the continuously variable transmission 18.

The target rotational speed setting means 216 determines the speed ratio γ of the continuously variable transmission 18 or the input shaft rotational speed N _IN based on the required driving force of the vehicle and the vehicle speed determined based on the accelerator opening Acc, for example. A target speed ratio γ _tgt or a target input rotational speed N _{IN_tgt} which is a target value is set. The target rotational speed setting means 216 is configured to input the target rotational speed on the input side based on, for example, the accelerator operation amount θACC representing the driver's requested output amount and the vehicle speed V (corresponding to the output shaft rotational speed NOUT) from the automatic shift map shown in FIG. N _{IN_tgt} is calculated. The map in FIG. 6 corresponds to the shift condition, and the target rotational speed _{NIN_tgt} that sets a larger gear ratio γ is set as the vehicle speed V is low and the accelerator operation amount Acc is large. Further, since the vehicle speed V corresponds to the output shaft rotational speed N _OUT , the target rotational speed N _{IN_tgt} that is the target value of the input shaft rotational speed N _IN corresponds to the target speed ratio γ _tgt , and the minimum speed change of the continuously variable transmission 18 is _achieved. It is determined within the range of the ratio γmin and the maximum gear ratio γmax. The automatic shift map is stored in advance in a storage device (not shown) of the electronic control unit 50. The target rotational speed setting means 216 automatically and continuously changes the speed ratio γ of the continuously variable transmission 18 according to the driving state of the vehicle, that is, the vehicle speed V, the accelerator operation amount (opening) Acc, and the like.

The speed ratio control means 210 performs feedback control of the speed ratio γ of the continuously variable transmission 18 and is started by the control start means 208. The gear ratio control unit 210 calculates a deviation ΔN _IN between the input shaft rotation speed N _{IN of the} continuously variable transmission 18 and a target input rotation speed N _{IN_tgt} set by a target rotation speed setting unit 216 described later. And a shift hydraulic pressure for setting a hydraulic pressure for changing the gear ratio of the continuously variable transmission 18 based on a deviation calculated by the deviation calculation means 212, a feedback gain controlled by a follow-up control means 218 described later, and the like. A setting means 214 is functionally included.

Among these, the deviation calculating means 212 is the gear ratio control means 210 and the deviation ΔN _IN between the input shaft rotational speed N _{IN of the} continuously variable transmission 18 and the target input rotational speed N _{IN_tgt} set by the target rotational speed setting means 216. Is calculated. As the input shaft rotational speed N _IN , for example, the turbine rotational speed _NT detected by the turbine rotational speed sensor 54 of the torque converter 14 may be used.

The transmission hydraulic pressure setting means 214 is a hydraulic pressure for changing the transmission ratio of the continuously variable transmission 18 based on the deviation calculated by the deviation calculation means 212, the feedback gain controlled by the follow-up control means 218 described later, and the like. And control for outputting the hydraulic pressure. Specifically, feedback control of an electromagnetic on-off valve or the like of the hydraulic control circuit 100 is performed to control supply and discharge of hydraulic oil to and from the hydraulic cylinder of the input side variable pulley 42. Feedback control by the shift hydraulic pressure setting means 214, the deviation calculated by said deviation calculating means 212 and 0, i.e., the feedback control for the actual input shaft speed N _IN follows the target input rotation speed N _{IN_tgt} This is performed using a feedback gain controlled by a follow-up control means 218 described later.

As described above, the feedback control by the transmission ratio control unit 210 is performed by the transmission belt being completed by the garage control by the garage control unit 224, the neutral control by the neutral control unit 226 ending, or the sudden stop determination unit 228. When it is determined that the vehicle 48 is not returned to the predetermined position, at least one of starting the vehicle is established by the control start unit 208. At this time, when the garage control by the garage control means 224 or the return from the neutral control by the neutral control means 226 is performed by feedforward control, the stepless control when the return control from the garage control or neutral control ends. The transmission ratio of the transmission 18 is determined according to the course. For this reason, when the feedback ratio control means 210 starts the feedback control, the gear ratio deviation becomes large, and if the feedback control is performed based on the large deviation, an abrupt shift may be performed with the start of the feedback control. On the other hand, when the execution of the garage control by the garage control means 224 performed by the feedforward control is completed or when the return control from the neutral control by the neutral control means 226 is finished, the value of the deviation ΔN _IN does not cause a sudden shift. In order not to become large, the input rotation speed N _IN is continuously variable when the garage control by the garage control means 224 is completed or when the return control from the neutral control by the neutral control means 226 is finished. It is also conceivable to design the power transmission device 10 including the transmission 18. However, in order to realize such a method, the precision of parts required is severe, and there is a problem that the cost of parts increases.

  Therefore, in the control device for a continuously variable transmission according to the present invention, the followability control means 218 is provided to control the followability of the feedback control by the speed ratio control means 210, thereby reducing the occurrence of sudden shift.

  The followability control means 218 controls the followability of the feedback control in the transmission hydraulic pressure setting means 214 of the transmission ratio control means 210. The followability control means 218 functionally includes a followability reduction means 222 that changes the followability so as to decrease, and a followability return means 220 that restores the followability reduced by the followability reduction means 222. It is configured to include.

Of these, the follow-up performance lowering means 222 includes an actual input shaft rotational speed N _IN and a target input rotational speed N _{IN_tgt} calculated by the deviation calculating means 212 when feedback control by the transmission hydraulic pressure setting means 214 is started. When the value of the deviation ΔN _IN exceeds a predetermined follow-up decrease determination value N _{IN_th1} , the gear ratio control means is compared with the case where the value of the deviation ΔN _IN does not exceed the follow-up decrease determination value N _{IN_th1.} The follow-up performance of the feedback control in the shift oil pressure setting means 214 of 210 is lowered. Specifically, for example, the followability control means 218 gives two values K1 as values used as gains in the feedback control to the transmission hydraulic pressure setting means 214 of the transmission ratio control means 210, and K2 larger than K1. The follow-up performance lowering means 222 controls the shift hydraulic pressure setting means 214 to use K1 which is a smaller value instead of K2 as a feedback gain in the feedback control. By doing so, the followability of the control by the followability lowering means 222 is lowered.

Followability return means 220, if below the shift hydraulic pressure setting means 214 predetermined trackability return judgment value N _{IN_th2} the value of the deviation .DELTA.N _IN is predetermined during execution of the feedback control by, the value of the deviation .DELTA.N _IN The follow-up performance before the feedback control in the shift oil pressure setting means 214 that has been lowered when the follow-up return judgment value N _{IN_th2} is exceeded is restored to the follow-up performance. Specifically, for example, the followability control means 218 gives two values K1 as values used as gains in the feedback control to the transmission hydraulic pressure setting means 214 of the transmission ratio control means 210, and K2 larger than K1. If so, the follow-up return means 220 controls the shift hydraulic pressure setting means 214 to use K2 which is a larger value instead of K1 as a feedback gain in the feedback control. . In this way, when the followability of the control by the followability reducing means 222 has been lowered, the state before the followability is lowered is restored.

FIG. 7 is a flowchart for explaining the outline of the control operation in the embodiment of the control device for the continuously variable transmission according to the present invention. This flowchart is repeatedly executed at a predetermined interval such as several ms. First, in a step (hereinafter, “step” is omitted) S1 corresponding to the gear ratio control means 210, the control of the gear ratio γ (input shaft rotational speed N _IN ) of the continuously variable transmission 18 is performed. It is determined whether feedback control based on the deviation ΔN _IN is being performed. When the feedback control of the gear ratio γ is not performed, the determination of this step is affirmed and S2 and the subsequent steps are executed because there is a possibility of a sudden shift accompanying the start of the feedback control. If feedback control of the gear ratio γ has already been performed, the determination in this step is denied and the present flowchart is temporarily terminated.

  In S2 corresponding to the control start means 208, it is determined whether or not feedback control of the gear ratio γ has been started. Specifically, for example, when the execution of the garage control is completed, the neutral control by the neutral control means 226 is completed, or the sudden stop determination means 206 determines that the transmission belt 48 is not returned to the predetermined position. If at least one of the start of the vehicle is established, the feedback control is started and the determination in this step is affirmed. If the determination in this step is affirmed, S3 and the subsequent steps are executed on the assumption that there is a possibility of a sudden shift accompanying the start of feedback control. If the determination in this step is negative, this S2 is repeatedly executed, and a standby is performed until feedback control is started.

S3 corresponds to the deviation calculating means 212 of the gear ratio control means 210, the followability reducing means 222 of the followability control means 218, and the like. In S3, a predetermined follow-up decrease determination value in which the value of the deviation ΔN _IN between the target input rotational speed N _{IN_tgt} set in accordance with the driving state of the vehicle and the actual input shaft rotational speed N _IN is predetermined. It is determined whether or not (threshold) N _{IN_th1} is exceeded. When the value of the deviation ΔN _IN exceeds the followability drop determination value (threshold value) _{NIN_th1} , the determination in this step is affirmed and S4 is executed to reduce the followability of feedback control. When the value of the deviation ΔN _IN does not exceed the followability lowering determination value (threshold value) _{NIN_th1} , the determination in this step is denied, and S6 is executed because it is not necessary to reduce the followability of the feedback control. As the actual input shaft rotation speed N _IN , the turbine rotation speed _NT detected by the turbine rotation speed sensor 54 can be used.

In S4 corresponding to the followability reducing means 222 of the followability control means 218, the shift hydraulic pressure setting means 214 of the speed ratio control means 210, etc., the followability in feedback control is reduced by lowering the value of the feedback gain in feedback control. Is done. As a result, even when the value of the deviation ΔN _IN is large, the amount of control is reduced by reducing the gain value, so that sudden shift is reduced. Specifically, two gains K1 and K2 larger than K1 are prepared so as to be selectable in advance, and when the follow-up performance of the feedback control is reduced in this step S4, it is replaced with K2. The value of the feedback gain is reduced by using K1 which is a smaller value as the feedback gain.

S5 corresponds to the deviation calculation means 212 of the gear ratio control means 210, the followability return means 220 of the followability control means 218, and the like. In S5, it is determined whether or not the value of the deviation ΔN _IN is below a predetermined follow-up return determination value (threshold value) N _{IN_th2} . When the value of the deviation ΔN _IN is _less than the followability return determination value (threshold value) N _{IN_th2} , the determination in this step is affirmed and S6 is executed to restore the followability of feedback control. When the value of the deviation ΔN _IN does not fall below the follow-up return determination value (threshold value) N _{IN_th2} , the determination at this step is denied and S5 is repeatedly executed until the determination at S5 is affirmed. If the determination in S5 is negative, the deviation ΔN _IN is not small enough to restore the follow-up performance of the feedback control, that is, there is still a possibility of sudden shift. This corresponds to the continued execution of the reduced feedback control.

  In S6 corresponding to the followability return means 220 of the followability control means 218, the shift hydraulic pressure setting means 214 of the speed ratio control means 210, etc., this corresponds to the case where the feedback gain value in the feedback control cannot be lowered in S4. Set to the value you want. That is, the follow-up performance in feedback control is restored. As a result, the follow-up performance of the feedback control becomes faster than when the feedback control has been lowered in S4, so that the control response is improved. Specifically, two gains K1 and K2 larger than K1 are prepared in advance, and the feedback gain set to K1 in step S4 is a value larger than K1 instead of K1. Thus, the feedback gain value that has been lowered is restored.

FIG. 8 is a time chart showing an embodiment of the control device for the continuously variable transmission according to the present invention. The signal pressure S1 for controlling the clutch apply control valve 102 and the speed ratio γ of the continuously variable transmission 18 are shown in FIG. And the target value γ _tgt , the hydraulic pressure Pinfb corresponding to the hydraulic pressure supplied to the primary sheave 42, the engine rotational speed Ne, the turbine rotational speed Nt, and the time change of the input shaft rotational speed Nin of the continuously variable transmission 18. It is. In the example of FIG. 8, the garage control is performed in a state where the accelerator pedal is not depressed, that is, the engine speed is not changed, and the feedback control is performed after the garage control is completed. Until time t1, garage control by the garage control means 224 is executed. During the execution of the garage control, the signal pressure S1 for controlling the operation of the clutch apply control valve 102 is on the fail / garage side. The speed ratio γ is changed by supplying the hydraulic pressure Pd of the driven hydraulic actuator 46 c of the primary sheave 42 of the continuously variable transmission 18. Therefore, the hydraulic pressure Pinfb has not changed. On the other hand, the turbine rotational speed is decreased as the forward clutch C1 is engaged, and when the forward clutch C1 is completely engaged and the execution of the garage control is completed, the input shaft rotational speed N _{IN of the} continuously variable transmission 18 is reached. To match.

When execution of the garage control by the garage control means 224 is completed at time t1, and the start of feedback control by the transmission ratio control means 210 is determined by the control start means 208, the feedback control is executed from time t2. That is, after time t2, it corresponds to the target speed ratio γ _tgt corresponding to the target input speed N _{IN_tgt} determined by the target speed setting means 216 according to the driving state of the vehicle and the actual input shaft speed N _IN . Feedback control is performed so as to reduce the deviation Δγ from the speed ratio γ. Further, the control of the gear ratio γ is executed by changing the hydraulic pressure Pinfb. Here, the hydraulic pressure Pinfb is obtained by multiplying the feedback gain by the deviation Δγ. After time t2 in FIG. 8, the solid line shows an example in which the control device for a continuously variable transmission of the present invention is applied. The broken line shows an example in which the control device for continuously variable transmission of the present invention is not applied and a predetermined feedback gain of 1 is used. The feedback gain of 1 corresponds to, for example, the larger gain K2 of the two feedback gains K1 and K2 included in the tracking control unit 218 in the embodiment of the present invention. It is larger than the feedback gain K1 selected by the means 222.

In FIG. 8, at the time t2, the follow-up performance of the feedback control by the follow-up performance lowering means 222 is reduced, _assuming that the deviation ΔN _IN exceeds the follow-up performance decrease determination value N _{IN_th1} . Specifically, the gain K1 is used as a gain value in the feedback control. This gain K1 is a value smaller than K2 which is a gain when the followability is not lowered by the followability lowering means 222.

  When the control device for continuously variable transmission of the present invention represented by a broken line in FIG. 8 is not applied and the case where the control device for continuously variable transmission of the present invention represented by a solid line is applied are compared. When the control device for a continuously variable transmission according to the present invention is not applied, the deviation Δγ converges quickly because the feedback gain value is large. In other words, a sudden shift occurs. On the other hand, when the continuously variable transmission control device of the present invention is applied, the time required for the deviation Δγ to converge is longer than when the continuously variable transmission control device of the present invention is not applied. There is no sudden shift.

  As described above, the feedback gain K1 is changed so that, for example, the speed of the shift allowed in the feedback control, that is, the shift does not correspond to the sudden shift, and the time required for the shift is not excessively long. It may be determined in advance by simulation or experiment.

At time t3, the follow-up of feedback control by the follow-up return means 220 is performed on the _assumption that the deviation ΔN _IN exceeds the follow-up return determination value N _{IN_th2} . In other words, the feedback gain that was previously set to K1 is set to K2.

According to the above-described embodiment, the difference ΔN _IN between the target input rotational speed N _{IN_tgt} corresponding to the target speed ratio γ _tgt and the input shaft rotational speed N _IN corresponding to the actual speed ratio γ and the feedback gain are used. Control device 50 for a continuously variable transmission having speed ratio control means 210 that performs feedback control so that deviation ΔN _IN is eliminated, and control start means 208 that starts the feedback control when a predetermined start condition is satisfied. When the feedback is started by the control start unit 208, if the deviation ΔN _IN exceeds a predetermined followability drop determination value N _{IN_th1} , the followability drop means 222 of the followability control means 218 sets the deviation ΔN _IN. being low followability of the feedback control than without exceed the conformability decreases determination value N _{IN_th1} Deviation .DELTA.N _IN sudden change speed of execution is reduced in the case larger. In addition, as a result of the sudden shift being reduced, it is possible to prevent the hydraulic pressure related to execution of the shift from being unnecessarily high as in the case of Pinfb, thereby contributing to improvement in fuel consumption.

  Further, according to the above-described embodiment, the follow-up control means 218 reduces the follow-up performance by reducing the feedback gain K, that is, by lowering K1, so that it is possible to suitably reduce the execution of the sudden shift.

  Further, according to the above-described embodiment, the predetermined start condition in the control start unit 208 is that the garage shift is completed, and feedback control is executed based on the completion of the garage shift by the garage control unit 224. Therefore, the input shaft rotation speed sensor of the continuously variable transmission 18 or the like becomes unnecessary. Further, the accuracy of parts in the power transmission device 10 including the continuously variable transmission 18 can be relaxed.

  Further, according to the above-described embodiment, the predetermined start condition in the control start unit 208 is that after the return from the neutral control, and the feedback control is executed based on the end of the neutral control by the neutral control unit 226. Therefore, the input shaft rotation speed sensor of the continuously variable transmission 18 or the like becomes unnecessary. Further, the accuracy of parts in the power transmission device 10 including the continuously variable transmission 18 can be relaxed.

  Further, according to the above-described embodiment, the predetermined start condition in the control start means 208 is that the transmission belt in the continuously variable transmission has not returned to the predetermined position after the vehicle is stopped. Since feedback control is executed, the input shaft rotational speed sensor of the continuously variable transmission 18 or the like is not necessary. Further, the accuracy of parts in the power transmission device 10 including the continuously variable transmission 18 can be relaxed. Even when the transmission belt 48 does not return to the predetermined position after the sudden stop, the execution of the sudden shift can be suitably reduced.

Further, according to the above-described embodiment, the followability return means 220 of the followability control means 218 returns the feedback followability when the deviation ΔN _IN is lower than the predetermined followability return determination value N _{IN_th2} , that is, Since the feedback gain that was set to K1 is set to K2, which is larger than K1, the deviation ΔN _{IN falls} below the follow-up return determination value N _{IN_th2} , and the follow-up property (responsibility) is obtained when the risk of sudden shift is low. ) Can be improved. In other words, only in a traveling state where there is a risk of sudden gear change, the follow-up property is lowered so as to reduce the sudden gear shift, so that both the follow-up property to the gear shift and the reduction of the sudden gear change are compatible.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

For example, in the above-described embodiment, the follow-up control unit 218 has two values K1 and K2 larger than K1 as values used as gains in the feedback control. Although K1 which is a value smaller than K2 is controlled to be used as a feedback gain, and the follow-up return means 220 is controlled to use K2 which is a value larger than K1 as a feedback gain, it is not limited to this mode. For example, a relationship of the gain K with respect to the deviation ΔN _IN as shown by the straight line R1 or the curve R2 in FIG. 9 is previously provided, and the followability reducing means 222 of the followability control means 218 determines the gain value in the feedback control. The control start unit 208 may determine the deviation ΔN _IN at the time when the start of the feedback control is determined. Moreover, follow-up performance reduction unit 222 of the tracking control means 218, the value of the gain in the feedback control, may be determined every predetermined time interval based on the relationship in accordance with the deviation .DELTA.N _IN.

In the illustrated embodiment, trackability return means 220 of the follow-up control means 218 of the follow-up performance reduction unit 222 and the follow-up performance reduction determination value N _{IN_th1} is an index for performing the reduction of the followability tracking control means 218 Although it is determined separately from the follow-up return determination value _{NIN_th2,} which is an index for performing the follow-up return, it does not prevent both from being the same value.

In the above-described embodiment, the example in which the turbine rotation speed _NT detected by the turbine rotation speed sensor 54 of the torque converter 14 is used as the input shaft rotation speed N _IN of the continuously variable transmission 18 is shown. In the case where an input shaft rotation speed sensor for detecting the rotation speed N _IN is provided, the use of the input shaft rotation speed N _IN detected by the input shaft rotation speed sensor is not prevented.

  In the above-described embodiment, the neutral control by the neutral control means 226 and the garage control by the garage control means 224 have been described using the forward clutch C1, but can be similarly realized using the reverse brake B1. It is. Further, neutral control and garage control using a start clutch provided separately from the forward clutch C1 may be performed.

  In addition, although not illustrated one by one, the present invention is implemented with various modifications within a range not departing from the gist thereof.

18: continuously variable transmission 36: input shaft 42, 46: pulley 44: output shaft 48: transmission belt 50: control device 208 for vehicle continuously variable transmission: control start means (S2)
210: Gear ratio control means (S3, S5)
218: Follow-up control means (S4)
224: Garage control means (S2)
226: Neutral control means (S2)
228: Sudden stop determination means (S2)
γ _tgt : target gear ratio γ: gear ratio Δγ: gear ratio deviations K, K1, K2: feedback gain N _{IN — th1} : determination value (following performance decrease determination value)
N _{IN — th2} : End determination value (trackability return determination value)

Claims (6)

Gear ratio control means for performing feedback control based on the deviation between the target gear ratio and the actual gear ratio and the feedback gain so that the deviation is eliminated;
In a control device for a continuously variable transmission for a vehicle, comprising control start means for starting the feedback control when a predetermined start condition is satisfied,
When the feedback is started by the control start means, if the deviation exceeds a predetermined determination value, the follow-up control lowers the follow-up performance of the feedback control than when the deviation does not exceed the determination value. Having further means,
A control device for a continuously variable transmission for a vehicle. 2. The control device for a continuously variable transmission for a vehicle according to claim 1, wherein the followability control means lowers the followability by reducing the feedback gain. 3.   The control device for a continuously variable transmission for a vehicle according to claim 1 or 2, wherein the predetermined start condition is after completion of execution of a garage shift.   The control device for a continuously variable transmission for a vehicle according to claim 1, wherein the predetermined start condition is after return from neutral control. The continuously variable transmission is a belt type continuously variable transmission in which power is transmitted between an input shaft and an output shaft by a pair of pulleys having variable groove widths and a transmission belt wound around the pair of pulleys.
The control device for a continuously variable transmission for a vehicle according to claim 1, wherein the predetermined start condition is that a transmission belt in the continuously variable transmission does not return to a predetermined position after the vehicle is stopped. 6. The continuously variable transmission for a vehicle according to claim 1, wherein the follow-up control unit restores the follow-up of the feedback when the deviation falls below a predetermined end determination value. Machine control device.

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