JP2008008339A - Transmission control device for vehicular continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain slipping of a belt in starting of a vehicle when a speed ratio of a continuously variable transmission is determined to be the lowest speed side speed ratio, in a transmission control device for the continuously variable transmission wherein hydraulic fluid is sealed in a driving side hydraulic actuator when the vehicle speed is equal to or lower than the prescribed vehicle speed. <P>SOLUTION: In this transmission control device, supply/discharge of the hydraulic fluid to a driving side hydraulic cylinder 42c is controlled by a transmission control means 152 in order to maintain a maximum speed ratio γmax in starting of the vehicle after stopping the vehicle on the condition that a transmission belt 48 is determined as being in the most reduced speed state in stopping of the vehicle by a most reduced speed state determination means 166 and fluctuation is not determined as occurring in input torque T<SB>IN</SB>input to a driving side pulley 42 when closing control is performed by a torque fluctuation determination means 168. Accordingly, the hydraulic fluid is not supplied/discharged to the driving side hydraulic cylinder 42c when the fluctuation occurs in the input torque T<SB>IN</SB>and the transmission belt 48 is out of the most reduced speed state, and slipping of the belt can be prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a shift control device for a belt-type continuously variable transmission having a pair of pulleys whose effective diameter is changed by a hydraulic actuator and a transmission belt wound around the pair of pulleys, and more particularly It is about control.

  A drive-side hydraulic actuator for changing the groove width of a drive-side pulley and its drive in a transmission control device for a continuously variable transmission for a vehicle having a drive-side pulley, a driven-side pulley, and a belt wound around both pulleys In a vehicle state in which the rotational speed of the rotating member exceeds a predetermined vehicle speed that can be detected by the rotational speed sensor. While the variable speed control valve controls the supply and discharge of hydraulic fluid to the drive hydraulic actuator based on the deviation between the target value and the actual value of the rotational speed, the continuously variable transmission is shifted, but the rotational speed is difficult to detect. When the vehicle speed is less than the predetermined vehicle speed, the gear ratio of the continuously variable transmission is determined by confining the hydraulic oil in the drive hydraulic actuator by the shift control valve. It is well known that the transmission ratio.

  For example, when the vehicle travels above a predetermined vehicle speed, the drive oil is supplied to the drive-side hydraulic actuator by the shift control valve, thereby narrowing the groove width of the drive-side pulley and upshifting the continuously variable transmission, By discharging the hydraulic oil from the drive side hydraulic actuator, the groove width of the drive side pulley is widened and the continuously variable transmission is downshifted. Further, when the vehicle is stopped, so-called closing control is performed in which the hydraulic oil is confined in the drive side hydraulic actuator by the speed change control valve, so that the speed ratio of the continuously variable transmission becomes the lowest speed side speed ratio. That is, the belt is returned to the maximum deceleration state.

  In the closing control described above, since a slight hydraulic pressure is applied to the drive side hydraulic actuator, an upshift may occur with the rotation of the drive side pulley when the vehicle starts after the closing control. There is. Therefore, when the vehicle starts after the closing control, a so-called duty down control (Duty Down control) is performed in which a downshift command is output until the predetermined vehicle speed is exceeded and the hydraulic oil in the drive side hydraulic actuator is discharged, and the upshift is performed. It may be possible to prevent and maintain the transmission gear ratio at the lowest speed side gear ratio. Even when the duty-down control is executed and the hydraulic oil in the drive-side hydraulic actuator is discharged, the groove width of the drive-side pulley is increased when the belt is returned to the maximum deceleration state when the vehicle is stopped. Never happen. However, if the belt is not returned to the maximum deceleration state when the vehicle is stopped, the groove width of the driving pulley is increased and the belt is loosened when the duty down control is executed. is there.

  In order to avoid the occurrence of such belt slip, for example, Patent Document 1 determines whether or not the belt has returned to the maximum deceleration state, and also determines that the belt has returned to the maximum deceleration state when the vehicle starts. On the condition that this is done, a shift control device for a belt-type continuously variable transmission that outputs a downshift command has been proposed.

JP 2002-181177 A

  By the way, a so-called garage shift in which the shift position is operated between the travel position and the neutral position during the closing control in which it is determined that the belt has returned to the maximum deceleration state, or the shift position is set as the travel position. In some cases, so-called neutral control is performed in which the power transmission path to the continuously variable transmission is interrupted. When such a garage shift or neutral control is performed, the input torque input to the drive-side pulley varies and the drive-side pulley rotates, which may cause an upshift as described above. Further, depending on the state of the vehicle such as a slope, the vehicle may start to move when the brake is turned off, and an upshift may occur due to the rotation of the driving pulley even in such a case.

  When such an upshift occurs and the belt deviates from the maximum deceleration state, it may be denied that the belt has returned to the maximum deceleration state, but it is difficult to detect the rotation speed with the rotation speed sensor. In a vehicle state of a predetermined vehicle speed or less, even if the belt is out of the most decelerated state, the determination to that effect is not denied and it is determined that the belt continues to return to the most decelerated state.

  Then, even if the above-described upshift occurs and the belt is out of the most decelerated state, a downshift command is output as proposed in Patent Document 1, so the drive pulley There is a possibility that the groove width increases, the belt loosens, and belt slippage occurs.

  The present invention has been made in the background of the above circumstances, and the object of the present invention is to set a gear ratio to a predetermined gear ratio in a state where the hydraulic oil is confined in the drive side hydraulic actuator in a vehicle state below a predetermined vehicle speed. In a transmission control device for a continuously variable transmission for a vehicle, the occurrence of belt slip is suppressed when the vehicle starts when it is determined that the transmission ratio of the continuously variable transmission is at the lowest speed side transmission ratio. is there.

  To achieve this object, the gist of the invention according to claim 1 is that (a) a driving pulley, a driven pulley, and both pulleys are provided in a power transmission path between a driving power source and driving wheels. In a vehicle in which a continuously variable transmission having a wound belt is disposed, a drive-side hydraulic actuator for changing the groove width of the drive-side pulley and the supply / discharge of hydraulic fluid to the drive-side hydraulic actuator are controlled. A shift control valve that changes the groove width of the drive pulley by controlling the supply and discharge of hydraulic fluid to the drive hydraulic actuator by the shift control valve in a vehicle state exceeding a predetermined vehicle speed. While shifting the transmission, in the vehicle state below a predetermined vehicle speed, the above-mentioned state is set as a state in which hydraulic oil is confined in the drive side hydraulic actuator by the shift control valve. A transmission control device for a continuously variable transmission for a vehicle having a transmission ratio of a stepped transmission as a predetermined transmission ratio, wherein (b) whether the transmission ratio of the continuously variable transmission is at the lowest speed side transmission ratio when the vehicle is stopped And (c) the driving when the hydraulic oil is confined in the driving hydraulic actuator by the shift control valve in a vehicle state equal to or lower than the predetermined vehicle speed. Torque fluctuation judging means for judging whether or not the input torque inputted to the side pulley has fluctuated; and (d) when the speed reduction ratio of the continuously variable transmission is at the lowest speed side gear ratio by the maximum deceleration judging means. On the condition that the torque variation determining means determines that the input torque input to the driving pulley does not fluctuate, the speed ratio of the continuously variable transmission is the lowest when starting the vehicle. Maintained at the gear ratio A start time of shift control means for controlling the hydraulic oil supply and discharge for said drive side hydraulic actuator by the shift control valve so that is to contain.

  In this way, it is determined that the speed ratio of the continuously variable transmission is at the minimum speed side speed ratio when the vehicle is stopped by the most deceleration determination means, and in the vehicle state below the predetermined vehicle speed, the shift control valve causes the inside of the drive side hydraulic actuator. When starting the vehicle, it is determined that there is no fluctuation in the input torque input to the driving pulley by the torque fluctuation judging means when the hydraulic oil is confined in the vehicle. In order to maintain the speed ratio of the stepped transmission at the lowest speed side speed ratio, that is, so that the belt is maintained in the lowest speed reduction state, the start-time speed change control means causes the hydraulic oil to be applied to the drive side hydraulic actuator by the speed change control valve. Since the supply and discharge are controlled, the hydraulic oil is confined in the drive side hydraulic actuator by the shift control valve in a low vehicle speed state below a predetermined vehicle speed. When the fluctuation of the input torque input to the driving pulley occurs and the belt deviates from the maximum deceleration state, hydraulic fluid is supplied to the driving hydraulic actuator by the shift control valve to bring the belt to the maximum deceleration state. No drainage occurs and belt slippage is prevented. Therefore, the occurrence of belt slip is suppressed when the vehicle starts when it is determined that the speed ratio of the continuously variable transmission is at the lowest speed side speed ratio.

  The invention according to claim 2 is the shift control device for a continuously variable transmission for a vehicle according to claim 1, wherein the torque fluctuation determining means is provided between the driving power source and the continuously variable transmission. Determining whether or not the input torque input to the drive pulley has changed based on whether or not the power transmission path is switched between the power transmission cut-off state and the power transmission enabled state, When the power transmission path is switched between the power transmission cutoff state and the power transmission enabled state, it is determined that the input torque input to the driving pulley has changed. In this way, when the power transmission path is in the power transmission cut-off state, the drive pulley is rotated by the vehicle moving with the brake off due to the vehicle state such as a slope, and the belt is removed from the maximum deceleration state. In this state, the hydraulic fluid is not supplied to or discharged from the drive side hydraulic actuator by the speed change control valve for bringing the belt to the maximum deceleration state, and belt slippage is prevented.

  Preferably, in the continuously variable transmission, a driven hydraulic cylinder as a driven hydraulic actuator that changes the groove width (effective diameter) of the driven pulley is provided integrally with the driven pulley, The hydraulic pressure of the hydraulic cylinder is regulated by a hydraulic control device so that the belt does not slip.

  Preferably, in the continuously variable transmission, the normal shift control of the continuously variable transmission executed in a vehicle state exceeding a predetermined vehicle speed, for example, a vehicle speed at which the rotation speed of the rotating member can be detected by a rotation speed sensor, For example, the target speed ratio is obtained according to a predetermined speed change condition, and the hydraulic oil to the drive side hydraulic cylinder as the drive side hydraulic actuator provided integrally with the drive side pulley so that the actual speed ratio becomes the target speed ratio. By changing the groove width of the drive pulley by feeding and discharging the gear, the gear ratio is feedback controlled, and the target rotation speed on the input side (drive source side) is set according to the vehicle speed and output rotation speed (drive wheel rotation speed). The gear ratio is feedback controlled by changing the groove width of the drive pulley by supplying and discharging hydraulic oil to the drive hydraulic cylinder so that the actual input rotation speed becomes the target rotation speed. Benefit such, it can adopt various aspects.

  The above-mentioned predetermined speed change conditions are set by a map or an arithmetic expression using, for example, driving conditions such as a driver output request amount (acceleration request amount) such as an accelerator operation amount and a vehicle speed (corresponding to an output rotation speed) as parameters. Is done.

  Further, the gear ratio of the continuously variable transmission is set to a predetermined value as a state in which hydraulic oil is confined in a drive-side hydraulic actuator that is executed in a vehicle state when the feedback control is difficult such as when traveling at a low vehicle speed below a predetermined vehicle speed. In the hydraulic control for changing the gear ratio, the hydraulic pressure of the driving hydraulic cylinder and the hydraulic pressure of the driven hydraulic cylinder are controlled independently, and a predetermined thrust ratio τ (= the hydraulic pressure of the driven hydraulic cylinder × the pressure receiving area of the driven hydraulic cylinder / The hydraulic pressure of the drive side hydraulic cylinder may be controlled so that the hydraulic pressure of the drive side hydraulic cylinder x the pressure receiving area of the drive side hydraulic cylinder). For example, the thrust ratio control in which the hydraulic pressure of the driven hydraulic cylinder is introduced as a pilot pressure The hydraulic pressure of the drive side hydraulic cylinder is controlled based on the control pressure output from the thrust ratio control valve. By Rukoto, it is desirable to configure such that a predetermined thrust ratio tau.

  Preferably, an engine that is an internal combustion engine such as a gasoline engine or a diesel engine is widely used as the driving power source. Furthermore, an electric motor or the like may be used in addition to the engine as an auxiliary driving power source. Alternatively, only an electric motor may be used as a driving power source.

  Hereinafter, embodiments 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 drive device 10 to which the present invention is applied. This vehicle drive device 10 is a horizontal automatic transmission, which is suitably 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 composed of 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. A lock-up clutch 26 is provided between the pump impeller 14p and the turbine impeller 14t, and a lock-up control valve (L not shown) in the hydraulic control circuit 100 (see FIGS. 2 and 3) is provided. The hydraulic pressure supply to the engagement side oil chamber and the release side oil chamber is switched by the (C / C control valve) or the like, thereby being engaged or released. The turbine impeller 14t is rotated integrally. The pump impeller 14p has a hydraulic pressure for controlling the transmission of the continuously variable transmission 18, generating a belt clamping pressure, controlling the engagement release of the lockup clutch 26, or supplying lubricating oil to each part. Is coupled to a mechanical oil pump 28 that is generated by being driven to rotate by the engine 12.

  The forward / reverse switching device 16 is composed mainly of a forward clutch C1, 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. The forward clutch C1 and the reverse brake B1 correspond to an intermittent device, both of which are hydraulic friction engagement devices that are frictionally engaged by a hydraulic cylinder.

  When the forward clutch C1 is engaged and the reverse brake B1 is released, the forward / reverse switching device 16 is brought into an integral rotation state, whereby the turbine shaft 34 is directly connected to the input shaft 36, and the forward power 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 cylinder (primary pulley side hydraulic cylinder) 42c and driven side hydraulic cylinder (secondary pulley side) as hydraulic actuators for applying thrust to change the V-groove width between the movable rotating bodies 42b and 46b provided Hydraulic cylinder) 46c, and the hydraulic fluid supply / discharge flow rate to the drive side hydraulic cylinder 42c is controlled by the hydraulic control circuit 100, so that the V groove widths of both variable pulleys 42, 46 change. As a result, the engagement diameter (effective diameter) of the transmission belt 48 is changed, and the gear ratio γ (= input shaft rotational speed N _IN / output shaft) The rotational speed N _OUT ) is continuously changed. The secondary pressure (hereinafter referred to as belt clamping pressure) Pd, which is the hydraulic pressure of the driven hydraulic cylinder 46c, is regulated by the hydraulic control circuit 100, so that the belt clamping pressure is reduced so that the transmission belt 48 does not slip. Be controlled. As a result of such control, a primary pressure (hereinafter referred to as shift pressure) Pin, which is the hydraulic pressure of the drive side hydraulic cylinder 42c, is generated.

  FIG. 2 is a block diagram for explaining a main part of a control system provided in the vehicle for controlling the vehicle drive device 10 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, representing the crankshaft rotation speed corresponding to the engine rotational speed crankshaft detected by the sensor 52 rotation angle (position) A _{CR (°)} and the rotational speed of the engine 12 (engine rotational speed) N _E Signal, a signal representing the rotational speed (turbine rotational speed) _NT of the turbine shaft 34 detected by the turbine rotational speed sensor 54, and an input that is the input rotational speed of the continuously variable transmission 18 detected by the input shaft rotational speed sensor 56. rotational speed (input shaft rotational speed) signal representing the N _iN of the shaft 36, a vehicle speed sensor (output shaft rotation speed sensor) 58 by the rotational speed (output of the output shaft 44 is the output rotational speed of the continuously variable transmission 18 detected axis rotation speed) N _OUT ie vehicle speed signal representing a vehicle speed V corresponding to the output shaft speed N _OUT, en detected by the throttle sensor 60 Intake pipe 32 throttle valve opening signal representing the throttle valve opening theta _TH of the electronic throttle valve 30 provided in (see FIG. 1) of the emission 12, the cooling water temperature T _W of the engine 12 detected by a coolant temperature sensor 62 signals representative 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, the accelerator opening is an operation amount of the accelerator pedal 68 detected by the accelerator opening sensor 66 an accelerator opening signal representative of the acc, brake operation signal indicating whether B _ON operation of the foot brake is a service brake, which is detected by a foot brake switch 70, a lever position (operation of the shift lever 74 detected by a lever position sensor 72 Position) An operation position signal representing _PSH is supplied.

Further, the electronic control device 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 command for driving the solenoid valve DS1 and the solenoid valve DS2 for controlling the flow of hydraulic fluid to the shift control command signal S _T for example drive side hydraulic cylinder 42c for changing the speed ratio γ of the continuously variable transmission 18 signal, a command signal for driving the squeezing force control command signal S _B for example, a linear solenoid valve pressure belt clamping pressure Pd adjusted SLS for aligning clamping pressure of the transmission belt 48, the engagement of the lock-up clutch 26, a release, A lock-up control command signal for controlling the slip amount, for example, a command signal for driving an on-off solenoid valve DSU (not shown) for switching the valve position of the lock-up control valve in the hydraulic control circuit 100 and a torque capacity of the lock-up clutch 26 command signal for driving the solenoid valve DS2 to adjust the line pressure P _L Such a command signal for driving a linear solenoid valve SLT and the linear solenoid valve SLS which controls are output to the hydraulic control circuit 100.

  The shift lever 74 is arranged, for example, in the vicinity of the driver's seat and is sequentially positioned in five lever positions “P”, “R”, “N”, “D”, and “L” (see FIG. 3). Any one of them is manually operated.

  The “P” position (range) releases the power transmission path of the vehicle drive device 10, that is, a neutral state (neutral state) where the power transmission of the vehicle drive device 10 is interrupted, and is mechanically output by the mechanical parking mechanism. The parking position (position) for preventing (locking) the rotation of 44, the “R” position is the reverse traveling position (position) for reversely rotating the output shaft 44, and the “N” position. Is a neutral position (position) for setting the neutral state in which the power transmission of the vehicle drive device 10 is interrupted, and the “D” position establishes an automatic transmission mode within a transmission range that allows the transmission of the continuously variable transmission 18. This is a forward travel position (position) that allows automatic shift control to be executed, and the “L” position is operated by a strong engine brake. An engine brake position (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 main part of the hydraulic control circuit 100 relating to the belt clamping pressure control, the transmission gear ratio control of the continuously variable transmission 18, and the engagement hydraulic pressure control of the forward clutch C1 or the reverse brake B1 accompanying the operation of the shift lever 74. FIG. In FIG. 3, the hydraulic control circuit 100 is regulated by a clamping pressure control valve 110 and a linear solenoid valve SLT that regulate the belt clamping pressure Pd, which is the hydraulic pressure of the driven hydraulic cylinder 46c, so that the transmission belt 48 does not slip. Further, it functions as a switching valve that is switched between a first position that outputs the control oil pressure P _SLT as the first oil pressure and a second position that outputs the output oil pressure P _LM2 as the second oil pressure from the line pressure modulator NO. A clutch apply control valve 112 that performs, a gear ratio control valve UP114 and a gear ratio control valve DN116 that function as a gear shift control valve that controls the flow rate of hydraulic oil to the drive hydraulic cylinder 42c so that the gear ratio γ can be continuously changed. The ratio between the transmission pressure Pin and the belt clamping pressure Pd is determined in advance. Thrust ratio control valve 118 to the oil passage is a manual valve 120 which is mechanically switched in accordance with the operation of the shift lever 74 as the forward clutch C1 and the reverse brake B1 are engaged or released.

The line pressure P _L as source pressure working oil pressure output from the mechanical oil pump 28 that is driven to rotate (see FIG. 1) (generated) by the engine 12, for example, a primary regulator valve (pressure regulating valve of the relief type ) it is adapted to be pressure adjusted to a value corresponding to the engine load and the like based on the signal pressure P _SLS from the signal pressure P _SLT or the linear solenoid valve SLS from the linear solenoid valve SLT by 124. The output oil pressure _{P LM2} is regulated on the basis by the line pressure modulator NO.2 valve 122 the line pressure _{P L} as source pressure to the signal pressure _{P SLS} from the signal pressure _{P SLT} or the linear solenoid valve SLS from the linear solenoid valve SLT It comes to be pressed. Output hydraulic pressure _{P LM3} is controlled hydraulic there used as the basic pressure of the (signal _{pressure) P SLT} and the signal pressure _{P SLS,} regulated to a constant pressure by the line pressure modulator NO.3 valve 126 to line pressure _{P L} as source pressure It comes to be pressed. Modulator pressure P _M is a used as the basic pressure of the electronic control unit 50 controls oil pressure P _DS2 is the output hydraulic pressure of the control oil pressure P _DS1 and the solenoid valve DS2 which is the output hydraulic pressure of the solenoid valve DS1 that is duty-controlled by, The output hydraulic pressure _PLM3 is adjusted to a constant pressure by the modulator valve 128 using the original pressure.

Wherein the manual valve 120, the engagement pressure _{P A} that is output from the clutch apply control valve 112 is supplied to the input port 120a. When the shift lever 74 is operated to the "D" position or "L" position, and for reverse engagement pressure P _A is supplied to the forward clutch C1 via a forward output port 120f as forward running output pressure The oil passage of the manual valve 120 is switched so that the hydraulic oil in the brake B1 is drained (discharged) to the atmospheric pressure, for example, from the reverse output port 120r through the discharge port EX, and the forward clutch C1 is engaged. The reverse brake B1 is released.

Also, operating the shift lever 74 when it is operated to the "R" position, the engagement pressure P _A is the reverse in the output port 120r are supplied to the reverse brake B1 via the and the forward clutch C1 as reverse running output pressure The oil passage of the manual valve 120 is switched so that the oil is drained (discharged) from the forward output port 120f through the discharge port EX to, for example, atmospheric pressure, the reverse brake B1 is engaged, and the forward clutch C1 is engaged. Be released.

  When the shift lever 74 is operated to the “P” position and the “N” position, the oil path from the input port 120a to the forward output port 120f and the oil path from the input port 120a to the reverse output port 120r are both And the oil passage of the manual valve 120 is switched so that the hydraulic oil in the forward clutch C1 and the reverse brake B1 is drained from the manual valve 120, and both the forward clutch C1 and the reverse brake B1 are connected. Be released.

The clutch apply control valve 112, the control hydraulic pressure _{P SLT} is supplied to the manual valve 120 as an engagement pressure _{P A} via the output port 112s from the input port 112i to and signal pressure _{P SLS} by being movable in the axial direction from the input port 112k first position constituting a first oil passage for supplying the input port 112j via an output port 112t to the line pressure modulator NO.2 valve 122 and the primary regulator valve 124 and (CONTROL position) the output hydraulic pressure _{P LM2} supplied through the output port 112t of the engagement pressure _{P a} is supplied to the manual valve 120 as a and the control pressure _{P SLT} through an output port 112s from the input port 112i to the line pressure modulator NO.2 valve 122 and the primary regulator valve 124 A spool valve element 112a positioned at a second position (NORMAL position) constituting the second oil passage, and a spring 112b as an urging means for urging the spool valve element 112a toward the second position side. And an oil chamber 112c that receives the control oil pressure _PDS1 to apply a thrust toward the first position to the spool valve element 112a, and a control oil pressure P to apply a thrust toward the first position to the spool valve element 112a. _{And a} diameter difference portion 112d for receiving _DS2 .

In the clutch apply control valve 112 configured as described above, for example, a garage shift in which the shift lever 74 is operated from the “N” position to the “D” position or the “R” position at a predetermined low vehicle speed or when the vehicle is stopped. N → D shift or N → R shift), the control oil pressure P _DS1 exceeding the predetermined pressure is supplied to the oil chamber 112c, and the control oil pressure P _DS2 exceeding the predetermined pressure is supplied to the diameter difference portion 112d. The control hydraulic pressure _PSLT is supplied to the forward clutch C1 or the reverse brake B1 via the manual valve 120 by switching to the first position shown in the right half of the line. Thereby, the engagement transient hydraulic pressure of the clutch C1 and the brake B1 at the time of the garage shift is regulated by the linear solenoid valve SLT as the first electromagnetic valve. For example, the control hydraulic pressure P _SLT is a hydraulic pressure for controlling the transient engagement state of the clutch C1 and the brake B1 in the N → D shift or the N → R shift, and the clutch C1 or the brake B1 is smoothly engaged. The pressure is regulated according to a predetermined rule so that a shock at the time of engagement is suppressed.

Further, for example, when the supply of at least one of the control hydraulic pressure _PDS1 and the control hydraulic pressure _PDS2 is stopped in the steady state in which the clutch C1 and the brake B1 are engaged after the garage shift, the left half of the center line The output hydraulic pressure _PLM2 is switched to the second position shown, and is supplied to the forward clutch C1 or the reverse brake B1 via the manual valve 120. As a result, the engagement of the clutch C1 and the brake B1 after the garage shift is held by the output hydraulic pressure _PLM2 . For example, the output hydraulic pressure P _LM2 is a predetermined hydraulic pressure for _bringing the clutch C1 and the brake B1 into a fully engaged state, and is adjusted to at least a predetermined constant pressure and a hydraulic pressure corresponding to the signal pressure P _SLT. To adjust the pressure.

Thus, the clutch apply control valve 112 controls the hydraulic oil supply passage to the clutch C1 or the brake B1 in order to control the transient engagement state of the forward clutch C1 or the reverse brake B1 during the garage shift. The second solenoid valve is connected to either the first oil passage that supplies the hydraulic pressure P _SLT and the second oil passage that supplies the output hydraulic pressure P _{LM2 in} order to bring the clutch C1 or the brake B1 into a fully engaged state in a steady state. functions as a switching valve for switching on the basis of the control oil pressure _{P DS1} and the control pressure _{P DS2} from the solenoid valve DS1 and the solenoid valve DS2 as.

In this embodiment, the output hydraulic pressure of the linear solenoid valve SLT is described in two ways, the control hydraulic pressure P _SLT and the signal pressure P _SLT , but the engagement transient hydraulic pressure at the time of the garage shift is the control hydraulic pressure P _SLT. , we used a clear distinction between pilot pressure for pressure regulating the line pressure P _L as a signal pressure P _SLT. That is, the linear solenoid valve SLT outputs the control hydraulic pressure P _SLT to control the transient engagement state of the forward clutch C1 or the reverse brake B1 when the clutch apply control valve 112 is switched to the first position. , and it outputs a signal pressure P _SLT to pressure the line pressure P _L tone when the clutch apply control valve 112 is switched to the second position. Further, the signal pressure P _SLT is a pilot pressure for pressure regulating the line pressure P _L by the primary regulator valve 124, directly supplied to the hydraulic actuator thereof engaging device for engaging the clutch C1 or the brake B1 Therefore, the hydraulic pressure is smaller than the output hydraulic pressure _PLM2 .

The speed ratio control valve UP114 is up to close the suppliable and output port 114k from the input port 114i to the line pressure P _L by being movable in the axial direction to the drive pulley 42 through the output port 114j The spool valve element 114a is positioned at the shift position and the original position where the driving pulley 42 is communicated with the input / output port 114k via the input / output port 114j, and the spool valve element 114a is biased toward the original position side. A spring 114b as an urging means, an oil chamber 114c that accommodates the spring 114b and receives the control oil pressure _PDS2 to _apply a thrust toward the original position to the spool valve element 114a, and the spool valve element 114a the control oil pressure P _DS1 to apply a thrust force toward the shift position side And a only put the oil chamber 114d.

Further, the transmission ratio control valve DN116 is provided so as to be movable in the axial direction, whereby a downshift position where the input / output port 116j communicates with the discharge port EX and an original position where the input / output port 116j communicates with the input / output port 116k. A spool valve element 116a positioned at the first position, a spring 116b as an urging means for urging the spool valve element 116a toward the original position, and a spring 116b that accommodates the spool valve element 116a in the original position side. An oil chamber 116c that receives the control hydraulic pressure _PDS1 to apply a thrust toward the engine, and an oil chamber 116d that receives the control hydraulic pressure _PDS2 to apply a thrust toward the downshift position to the spool valve element 116a. .

In the transmission ratio control valve UP114 and the transmission ratio control valve DN116 thus configured, in the closed state in which the spool valve element 114a is held in the original position in accordance with the urging force of the spring 114b as shown in the left half of the center line, The input / output port 114j and the input / output port 114k are in communication with each other, and the hydraulic oil in the drive pulley 42 (drive hydraulic cylinder 42c) is allowed to flow to the input / output port 116j. In the closed state in which the spool valve element 116a is held in the original position according to the urging force of the spring 116b as shown in the right half of the center line, the input / output port 116j and the input / output port 116k are communicated with each other, and the thrust ratio it is allowed that the thrust ratio control oil pressure P _tau from control valve 118 to flow to the input-output port 114k.

Further, when the control oil pressure _PDS1 is supplied to the oil chamber 114d, the spool valve element 114a is increased against the urging force of the spring 114b by a thrust according to the control oil pressure _PDS1 as shown in the right half of the center line. is moved to the shift position side, the line pressure _{P L} is supplied to the control oil pressure _{P DS1} to the corresponding flow rate at the input port output from 114i port 114j menstrual driving side hydraulic cylinder 42c, input and output ports 114k is blocked Accordingly, the flow of the hydraulic oil to the speed ratio control valve DN116 side is prevented. As a result, the transmission pressure Pin is increased, the V groove width of the drive pulley 42 is reduced, and the transmission ratio γ is reduced, that is, the continuously variable transmission 18 is upshifted.

When the control oil pressure _PDS2 is supplied to the oil chamber 116d, the spool valve element 116a is lowered against the urging force of the spring 116b by the thrust according to the control oil pressure _PDS2 , as shown in the left half of the center line. The oil is moved to the shift position side, and the hydraulic oil in the drive side hydraulic cylinder 42c is discharged from the input / output port 114j through the input / output port 114k and further through the input / output port 116j from the discharge port EX at a flow rate corresponding to the control oil pressure _PDS2 . As a result, the transmission pressure Pin is reduced, the V groove width of the drive pulley 42 is increased, and the transmission ratio γ is increased, that is, the continuously variable transmission 18 is downshifted.

Thus, the control oil pressure P _DS1 continuously upshift speed ratio control valve UP114 input to the line pressure P _L is supplied to the shift pressure Pin is increased to the drive side hydraulic cylinder 42c to be outputted, When the control hydraulic pressure _PS2 is output, the hydraulic oil in the drive side hydraulic cylinder 42c is discharged from the discharge port EX, and the shift pressure Pin is lowered and continuously downshifted.

For example, as shown in FIG. 4, it is actually determined from a previously stored relationship (shift map) between the vehicle speed V and the target input shaft rotational speed N _IN ^* that is the target input rotational speed of the continuously variable transmission 18 using the accelerator opening Acc as a parameter. The target input shaft rotational speed N _IN ^* of the input shaft 36 as a predetermined rotational member set based on the vehicle state indicated by the vehicle speed V and the accelerator opening Acc and the actual input shaft rotational speed (hereinafter referred to as actual input shaft rotational speed). The speed of the continuously variable transmission 18 is changed by feedback control in accordance with their rotational speed difference (deviation) ΔN _IN (= N _IN ^* −N _IN ) so that N _IN matches the speed (N _IN ). In other words, the V groove width of both variable pulleys 42 and 46 is changed by supplying and discharging the hydraulic oil to and from the drive side hydraulic cylinder 42c, and the gear ratio γ is continuously changed by feedback control. Is Sera.

The shift map in FIG. 4 corresponds to the shift conditions, and the target input shaft rotational speed N _IN ^* is set such that the larger the vehicle speed V is and the larger the accelerator opening Acc is, the larger the gear ratio γ is. Further, since the vehicle speed V corresponds to the output shaft rotation speed _{N OUT,} which is the target value of the input shaft rotational speed _{N IN} target input shaft rotational speed _{N IN} ^* is the target speed ratio ^{_{γ * (= N IN * /}} N OUT) And is determined within the range of the minimum speed ratio γmin and the maximum speed ratio γmax of the continuously variable transmission 18.

However, although it may be set a target input shaft rotational speed N _IN ^* as a target value of the input shaft rotational speed N _IN, preferably, during acceleration during running and deceleration (during coasting) and shifting transient state such as The basic target input shaft rotational speed N _INC , which is a value obtained by processing the target input shaft rotational speed N _IN ^*, is set according to the traveling state of the _vehicle , and the final input shaft rotation is based on the basic target input shaft rotational speed N _INC. A transient target input shaft rotational speed N _INT that is a target value of the speed N _IN is set. Accordingly, in this case, the rotational speed difference (deviation) ΔN _INT (= N _INT −N _IN ) of the transient target input shaft rotational speed N _INT and the actual input shaft rotational speed N _IN coincide with each other. In response to this, shifting of the continuously variable transmission 18 is executed by feedback control.

Further, the control hydraulic pressure _PDS1 is supplied to the oil chamber 116c of the transmission ratio control valve DN116, and regardless of the control hydraulic pressure _PDS2 , the transmission ratio control valve DN116 is closed to limit the downshift, while the control hydraulic pressure _{PDS2 changes} the speed. The oil ratio is supplied to the oil chamber 114c of the ratio control valve UP114, and regardless of the control oil pressure _PDS1 , the transmission ratio control valve UP114 is closed to prohibit the upshift. That is, the control when the hydraulic _{P DS1} and the control pressure _{P DS2} are not supplied together but of course, also, the speed change ratio control valve UP114 and speed ratio control valve when the control oil pressure _{P DS1} and the control pressure _{P DS2} is supplied together Each of the DNs 116 is in a closed state held in its original position. As a result, one of the solenoid valves DS1 and DS2 does not function due to a failure in the electrical system, and a sudden upshift occurs even when the control hydraulic pressure _PDS1 or the control hydraulic pressure _PDS2 continues to be output at the maximum pressure. It is possible to prevent a downshift or a belt slip due to the sudden shift.

The clamping force control valve 110, via an output port 110t by opening and closing an input port 110i to the line pressure P _L from the input port 110i by being movable in the axial direction to the driven side pulley 46 and the thrust ratio control valve 118 The spool valve element 110a that can supply the belt clamping pressure Pd, the spring 110b as an urging means that urges the spool valve element 110a in the valve opening direction, and the spring 110b is accommodated and opened to the spool valve element 110a. feedback oil accepting an oil chamber 110c that receives the control oil pressure P _SLS to apply a thrust force of the valve direction, the belt clamping pressure Pd output from the output port 110t to apply thrust in the valve closing direction to the spool valve element 110a Applying thrust in the valve closing direction to the chamber 110d and the spool valve element 110a And an oil chamber 110e that accepts modulator pressure P _M to.

In the clamping pressure control valve 110 thus configured, by the transmission belt 48 is line pressure P _L is continuously regulated pressure control control oil pressure P _SLS so as not slip as a pilot pressure, an output port 110t From this, the belt clamping pressure Pd is output.

For example, as shown in FIG. 5, the accelerator opening degree Acc corresponding to the transmission torque is used as a parameter, and is experimentally obtained and stored in advance so as not to cause belt slip between the gear ratio γ and the required hydraulic pressure (belt clamping pressure) Pd ^*. From the relationship (belt clamping pressure map), the belt of the driven hydraulic cylinder 46c is obtained so that the belt clamping pressure Pd ^* determined (calculated) based on the vehicle state indicated by the actual gear ratio γ and the accelerator opening Acc is obtained. The clamping pressure Pd is controlled, and the belt clamping pressure, that is, the frictional force between the variable pulleys 42 and 46 and the transmission belt 48 is increased or decreased according to the belt clamping pressure Pd.

The thrust ratio control valve 118, a thrust ratio control oil pressure P the line pressure _{P L} by opening and closing an input port 118i by being movable in the axial direction from the input port 118i via an output port 118t to the speed ratio control valve DN116 a spool valve element 118a that can supply _τ , a spring 118b as an urging means that urges the spool valve element 118a in the valve opening direction, and the spring 118b is accommodated in the valve opening direction in the valve opening direction. an oil chamber 118c that receives the belt clamping pressure Pd to apply a thrust force, a feedback oil chamber for receiving the thrust ratio control oil pressure P _tau output from the output port 118t to apply a thrust force in the valve closing direction to the spool valve element 118a 118d.

In the thrust ratio control valve 118 configured as described above, the pressure receiving area of the belt clamping pressure Pd in the oil chamber 118c a, the pressure receiving area of the thrust ratio control oil pressure P _tau in the feedback oil chamber 118d b, the biasing force of the spring 118b When F _S, an equilibrium state in the following equation (1).
_Pτ × b = Pd × a + F _S (1)
Therefore, the thrust ratio control oil pressure _Pτ is expressed by the following equation (2) and is proportional to the belt clamping pressure Pd.
_Pτ = Pd × (a / b) + F _S / b (2)

Then, the control oil pressure _P or _DS1 and the control pressure _{P DS2} is not supplied together, or the predetermined pressure or more control pressure _{P DS1} and the predetermined pressure or more control pressure _{P DS2} is both supplied, the speed ratio control valve UP114 and the speed ratio control when the valve DN116 has both been a closed state is held in the original position, consistent since the thrust ratio control oil pressure P _tau is supplied to the drive side hydraulic cylinder 42c, and the transmission pressure Pin thrust ratio control oil pressure P _tau Be made. That is, the shift pressure Pin and the belt clamping pressure Pd kept in a predetermined relationship the ratio between the thrust ratio control oil pressure P _tau i.e. the shift pressure Pin is outputted by the thrust ratio control valve 118.

For example, because of the accuracy of the input shaft rotation speed sensor 56 and the vehicle speed sensor 58, the detection accuracy of the input shaft rotation speed _NIN and the vehicle speed V is inferior in a low vehicle speed state below a predetermined vehicle speed V ′. Instead of feedback control of the gear ratio γ for eliminating the rotational speed difference (deviation) ΔN _IN at the time of starting, for example, neither the control hydraulic pressure P _DS1 nor the control hydraulic pressure P _DS2 is supplied, and the gear ratio control valve UP114 and the gear ratio control valve A so-called closing control is performed in which all the DNs 116 are closed. As a result, the shift pressure Pin proportional to the belt clamping pressure Pd is supplied to the drive side hydraulic cylinder 42c so that the ratio between the transmission pressure Pin and the belt clamping pressure Pd is a predetermined relationship during low vehicle speed traveling or starting. Thus, the belt slip of the transmission belt 48 from the time when the vehicle is stopped to the extremely low vehicle speed is prevented, and at this time, for example, the thrust ratio τ corresponding to the maximum gear ratio γmax (= driven hydraulic cylinder thrust W _OUT / driving side hydraulic cylinder) Thrust W _IN ; W _OUT is the belt clamping pressure Pd × the pressure receiving area of the driven hydraulic cylinder 46c, and W _IN is the speed change pressure Pin × the pressure receiving area of the driving hydraulic cylinder 42c). When (a / b) and F _S / b in the first term on the right side of 2) are set, a good start is performed at the maximum gear ratio γmax or a gear ratio γmax ′ in the vicinity thereof. The predetermined vehicle speed V ′ is a lower limit vehicle speed at which a predetermined feedback control can be executed as a vehicle speed V at which the rotational speed of the predetermined rotating member, for example, the input shaft rotational speed _NIN cannot be detected. For example, it is set to about 2 km / h.

FIG. 6 shows the relationship obtained and stored in advance between the speed ratio γ and the thrust ratio τ using the vehicle speed V as a parameter, and the first term (a It is a figure which shows an example when / b) is set. The parameter of the vehicle speed V shown by the one-dot chain line in FIG. 6 is a thrust ratio τ calculated in consideration of the centrifugal hydraulic pressure in the drive side hydraulic cylinder 42c and the driven side hydraulic cylinder 46c, and the intersections with the solid lines (V ₀ , V ₂₀ , V ₅₀ ) obtains a gear ratio γ as a predetermined gear ratio that can be held during the closing control. For example, as shown in FIG. 6, in the continuously variable transmission 18 according to this embodiment, the maximum speed ratio γmax can be maintained as a predetermined speed ratio when the vehicle speed V is 0 km / h, that is, the closing control is performed while the vehicle is stopped. .

FIG. 7 is a functional block diagram for explaining the main part of the control function by the electronic control unit 50. In FIG. 7, the target input rotation setting means 150 is configured to change the input shaft rotation speed N _IN based on the vehicle state indicated by the actual vehicle speed V and the accelerator opening Acc from a shift map stored in advance as shown in FIG. Set the target input shaft rotational speed N _IN ^* sequentially.

The shift control means 152 makes the actual input shaft rotational speed N _IN coincide with the target input shaft rotational speed N _IN ^* set by the target input rotational setting means 150, that is, the rotational speed difference (deviation) ΔN _IN (= N _IN ^* −N _IN ), the shift of the continuously variable transmission 18 is executed by feedback control according to the rotational speed difference ΔN _IN . That is, the speed change outputs a shift control command signal (oil pressure command) S _T for changing the V groove widths of both variable pulleys 42 and 46 by controlling the flow rate of hydraulic fluid to the driving side hydraulic cylinder 42c to the hydraulic control circuit 100 The ratio γ is continuously changed.

The belt clamping pressure setting means 154, for example, from the belt clamping pressure map obtained and stored experimentally in advance as shown in FIG. 5, for example, the actual accelerator opening Acc and the actual input shaft rotational speed N by the electronic control unit 50. _The belt clamping pressure Pd ^* is set based on the vehicle state indicated by the actual speed ratio γ (= N _IN / N _OUT ) calculated based on _IN and the output shaft rotational speed N _OUT . That is, the belt clamping pressure setting means 154 sets the belt clamping pressure Pd of the output side hydraulic cylinder 46c for obtaining the belt clamping pressure Pd ^* .

Belt clamping pressure control means 156, the belt clamping pressure setting means 154 clamping pressure control command signal S _B for pressurizing regulates the belt clamping pressure Pd of the driven-side hydraulic cylinder 46c as set belt clamping pressure Pd ^* is obtained by Output to the hydraulic control circuit 100 to increase or decrease the belt clamping pressure Pd ^* .

The hydraulic control circuit 100, the supply of hydraulic fluid to the shift control command signal solenoid valve DS1 and operates the solenoid valve DS2 to the drive side hydraulic cylinder 42c so the shift of the continuously variable transmission 18 is executed in accordance with S _T · to control the emissions, by operating the linear solenoid valve SLS so that the belt clamping pressure Pd ^* is increased or decreased pressure of the belt clamping pressure Pd adjusted in accordance with the above clamping force control command signal S _B.

In addition to the above-described function, the speed change control means 152 sets the speed ratio γ for eliminating the rotational speed difference ΔN _IN as a normal speed change control on condition that the vehicle speed V is equal to or lower than the predetermined speed V ′. Without performing the feedback control, the thrust ratio control valve 118 executes the closing control for maintaining the ratio between the transmission pressure Pin and the belt clamping pressure Pd in a predetermined relationship. That is, by closing the transmission ratio control valve UP114 and the transmission ratio control valve DN116, the operating oil is confined in the drive hydraulic cylinder 42c, and the transmission ratio γ of the continuously variable transmission 18 is set to a predetermined transmission ratio. A shift command (closed control command) signal S _T ′ for shifting control for low vehicle speed is output to the hydraulic control circuit 100 to establish a predetermined gear ratio.

The hydraulic control circuit 100 does not operate the solenoid valve DS1 and the solenoid valve DS2 so as to close the transmission ratio control valve UP114 and the transmission ratio control valve DN116 in accordance with the closing control command signal S _T ′, and controls the thrust ratio control. The valve 118 outputs a thrust ratio control hydraulic pressure _Pτ that maintains the ratio between the transmission pressure Pin and the belt clamping pressure Pd in a predetermined relationship.

The engine output control means 158 outputs an engine output control command signal S _E , for example, a throttle signal, an injection signal, an ignition timing signal, etc., to the throttle actuator 76, the fuel injection device 78, and the ignition device 80, respectively, for output control of the engine 12. To do. For example, the engine output control means 158 controls the engine torque T _E and outputs a throttle signal for opening and closing the electronic throttle valve 30 such that the throttle opening theta _TH corresponding to the accelerator opening Acc to the throttle actuator 76.

Shift position determining means 160, or determines the current lever position P _SH based on based on the lever position P _SH i.e. ON signal of the lever position P _SH, it determines an operation history of the shift lever 74. For example, the shift position determination unit 160 performs N → D shift determination, N → R shift determination, “D” position determination, “N” position determination, “R” position determination, and the like based on the lever position _PSH .

The engagement control means 162 switches the clutch apply control valve 112 to the first position side and moves forward when the garage shift is determined that the N → D shift or the N → R shift has been performed by the shift position determination means 160. In order to control the transitional engagement state of the clutch C1 or the reverse brake B1, the control hydraulic pressure P _SLT for gradually increasing the engagement hydraulic pressure is output so that the engagement shock is suppressed, and the line hydraulic pressure P _L is output. , _A garage shift command signal _SA that outputs a signal pressure P _SLS is output to the hydraulic pressure control circuit 100. For example, the engagement control unit 162 outputs the engagement transient hydraulic command pressure pcltexc to the hydraulic control circuit 100 as a command signal SLTDUTY for duty-controlling the linear solenoid valve SLT.

The hydraulic control circuit 100, in accordance with the garage shift command signal S _A at the time of the garage shifting, the clutch apply control valve 112 is first switched to the position side so actuates the solenoid valve DS1 and the solenoid valve DS2 to the predetermined pressure or more control pressure The control hydraulic pressure P _SLT is output by operating the linear solenoid valve SLT so that the forward clutch C1 or the reverse brake B1 is engaged according to a predetermined rule, while outputting the P _DS1 and the control hydraulic pressure P _{DS2 equal} to or higher than a predetermined pressure. It actuates the linear solenoid valve SLS so as the line pressure P _L is pressure regulated in accordance with the outputs and engine load and the like and outputs the signal pressure P _SLS with.

Further, the engagement control means 162 is configured to move the forward clutch C1 or the reverse brake in a steady state such as after a garage shift, for example, after a lapse of a predetermined time from the start of the garage shift, or after the control hydraulic pressure _PSLT becomes a predetermined engagement hydraulic pressure or higher. It switches the clutch apply control valve 112 to the completely engaged state by supplying the output hydraulic pressure P _LM2 to B1 to the second position, stationary control for outputting a signal pressure P _SLT to pressure the line pressure P _L tone Command signal S _A ′ is output to hydraulic control circuit 100. For example, the engagement control unit 162 outputs the line pressure command pressure plctgt to the hydraulic control circuit 100 as a command signal SLTDUTY for duty-controlling the linear solenoid valve SLT.

In a steady state, the hydraulic control circuit 100 supplies the output hydraulic pressure _PLM2 to the forward clutch C1 or the reverse brake B1 in accordance with the steady control command signal S _A ′ so that the fully engaged state is established. switches the clutch apply control valve 112 without operating the valve DS2 simultaneously to the second position, it actuates the linear solenoid valve SLT as the line pressure P _L is pressure regulated in accordance with the engine load or the like signal pressure P _SLT is output.

Thus, the linear solenoid valve SLT outputs the control hydraulic pressure P _SLT so that the forward clutch C1 or the reverse brake B1 is engaged at the first position of the clutch apply control valve 112 during garage shift (clutch pressure). Mode). The linear solenoid valve SLT, in the second position of the clutch apply control valve 112 is in a steady state, outputs a signal pressure P _SLT as the line pressure P _L is pressure regulated (referred line pressure mode). Further, in this clutch pressure mode, the control hydraulic pressure P _DS1 exceeding the predetermined pressure and the control hydraulic pressure P _DS2 exceeding the predetermined pressure are output, so that the control hydraulic pressure P _SLT is supplied to the forward clutch C1 or the reverse brake B1. At the same time, the closing control by the thrust ratio control valve 118 is performed so that a predetermined gear ratio is obtained.

That is, since it is not necessary to perform a shift during a garage shift, when the garage shift is performed, a control hydraulic pressure P _{DS1 that is} equal to or higher than a predetermined pressure as a signal hydraulic pressure for switching the clutch apply control valve 112 to the first position, and a predetermined hydraulic pressure. The control hydraulic pressure _PDS2 that is higher than the pressure is normally output from the solenoid valve DS1 and the solenoid valve DS2 that are operated to control the shift of the continuously variable transmission 18, and the thrust ratio control valve 118 controls the predetermined hydraulic ratio. Closed control is performed.

The neutral control condition determination unit 164 determines whether or not a predetermined neutral control condition is satisfied at the travel position of the shift lever 74. The predetermined neutral control condition is, for example, that the vehicle is stopped, the accelerator pedal 68 is not depressed, and the foot brake is depressed. More specifically, the neutral control condition determination unit 164 determines that the vehicle speed V is less than or equal to a predetermined stop determination value when the shift position determination unit 160 determines that the lever position P _SH is in the “D” position. There and determines if the accelerator opening Acc is less than a predetermined zero judgment value and a foot brake switch 70 is oN B _oN, the neutral control condition is satisfied. It should be noted that when neutral control is stopped with the release of the foot brake, the gradient detected by an acceleration sensor (not shown) is used to avoid the vehicle from sliding down until the forward clutch C1 is engaged. May be determined that the neutral control condition is not satisfied.

When the neutral control condition determining unit 164 determines that a predetermined neutral control condition is satisfied, the engagement control unit 162 switches the clutch apply control valve 112 to the first position side, and the power transmission path is the control hydraulic pressure P _SLT outputs and line pressure P neutral control command _L outputs a signal pressure P _SLS a to pressure regulating signal S _{a "for} the forward clutch C1 and the release state so as to be a neutral state For example, the engagement control means 162 outputs the release hydraulic pressure command pressure pclopen to the hydraulic pressure control circuit 100 as a command signal SLTDUTY for duty control of the linear solenoid valve SLT, and executes neutral control. . control pressure P _S to the forward clutch C1 and releasing state _T is the hydraulic forward clutch C1 does not have the engagement torque capacity.

In the neutral control, the hydraulic control circuit 100 operates the solenoid valve DS1 and the solenoid valve DS2 so as to switch the clutch apply control valve 112 to the first position side in accordance with the neutral control command signal S _A ″, thereby controlling the pressure above a predetermined pressure. When outputting the hydraulic pressure P _DS1 and the control hydraulic pressure P _{DS2 equal} to or higher than a predetermined pressure, and operating the linear solenoid valve SLT so that the forward clutch C1 is released, the control hydraulic pressure P _SLT is, for example, zero or engaged. Is adjusted to a hydraulic pressure corresponding to the return spring of the hydraulic actuator of the forward clutch C1 so that the response speed of the forward clutch C1 is increased.

Thus, the linear solenoid valve SLT outputs the control hydraulic pressure P _SLT so that the forward clutch C1 is slipped or released at the first position of the clutch apply control valve 112 during the neutral control. Further, at the time of this neutral control, the control hydraulic pressure P _{DS1 that is} equal to or higher than the predetermined pressure and the control hydraulic pressure P _{DS2 that} is equal to or higher than the predetermined pressure are output as in the garage shift, and therefore the control hydraulic pressure P _SLT is output to the forward clutch C1. Is simultaneously controlled by the thrust ratio control valve 118 so as to obtain a predetermined gear ratio.

Here, as described above, in the continuously variable transmission 18 of the present embodiment, the speed ratio γ is set to the maximum speed ratio γmax during the closing control while the vehicle is stopped, that is, the transmission belt 48 returns to the maximum deceleration position. (Hereinafter, referred to as the maximum deceleration state). Possibility since the thrust ratio control oil pressure P _tau is supplied to the drive side hydraulic cylinder 42c in this closed narrowing control, the upshift with the rotation of the drive pulley 42 at the time of vehicle start after closing control occurs There is.

Accordingly, the speed change control means 152 determines the vehicle speed at which normal speed change control can be executed when the vehicle starts after the speed reduction determination means 166 determines that the transmission belt 48 is in the lowest speed reduction state and the vehicle stops. Prior to the normal shift control until V exceeds a predetermined vehicle speed V ′, instead of the closing control, the hydraulic oil in the drive side hydraulic cylinder 42c is discharged in the same manner as during the downshift, so that the V groove of the drive side pulley 42 is discharged. A duty down control command signal S _T ″ for duty down control for maintaining the width at the maximum width is output to the hydraulic control circuit 100 to function as a start-time shift control means for maintaining the maximum deceleration state of the transmission belt 48. .

The hydraulic control circuit 100 operates the solenoid valve DS1 and the solenoid valve DS2 in accordance with the duty down control command signal S _T ″ to discharge the hydraulic oil from the drive side hydraulic cylinder 42c. Thereby, the upshift of the continuously variable transmission 18 is performed. Is prevented and the gear ratio γ is maintained at the maximum gear ratio γmax.

  The maximum deceleration determination means 166 determines whether or not the transmission gear ratio γ of the continuously variable transmission 18 is at the maximum transmission gear ratio (minimum speed side transmission gear ratio) γmax when the vehicle is controlled to be closed. For example, whether or not the vehicle has stopped in a state where the speed ratio γ is already at the maximum speed ratio γmax at the vehicle speed V exceeding the predetermined vehicle speed V ′ during vehicle deceleration traveling. Alternatively, the maximum speed ratio γmax that is estimated to be the maximum speed ratio γmax when the vehicle is stopped, although the speed ratio γ is not the maximum speed ratio γmax at the vehicle speed V that exceeds the predetermined vehicle speed V ′ during vehicle deceleration travel. The determination is made based on whether or not the predetermined gear ratio γmax ′ is in the vicinity.

  When it is determined by the most deceleration judging means 166 that the transmission belt 48 is in the most decelerated state, the electronic control device 50 sets the belt return determination flag Fbelt to ON, while the most deceleration judging means 166 causes the transmission belt 48 to be most decelerated. When it is determined that the belt is not in the state, the belt return determination flag Fbelt is turned off by the electronic control unit 50.

By the way, even if the duty-down control is executed and the hydraulic oil in the drive-side hydraulic cylinder 42c is discharged, the drive-side when the transmission belt 48 is actually returned to the maximum deceleration state when the vehicle is stopped. The V groove width of the pulley 42 is not increased. However, transmission when the belt 48 is determined to be in the highest speed reduction state, the garage shift and the neutral control is performed, the driving pulley 42 varies with the input torque T _IN is generated drive pulley that is input to the 42 There is a possibility that an upshift may occur due to the rotation of. Further, depending on the state of the vehicle such as a slope, the vehicle may start to move with the release of the foot brake. In such a case, an upshift may occur due to the rotation of the driving pulley 42.

  When such an upshift occurs and the transmission belt 48 deviates from the maximum deceleration state, the maximum deceleration determination means 166 may determine that the transmission belt 48 is not in the maximum deceleration state. In the vehicle state, it is not determined whether or not the transmission belt 48 is in the most decelerated state, and it is determined that the transmission belt 48 is in the most decelerated state.

Then, even when the transmission belt 48 is out of the most decelerated state, the duty reduction control command signal S _T ″ is transmitted by the shift control means 152 until the vehicle speed exceeds a predetermined vehicle speed V ′ when the vehicle starts. Therefore, the V-groove width of the driving pulley 42 is increased, the transmission belt 48 is loosened, and belt slipping may occur.

Therefore, the shift control means 152 is input to the driving pulley 42 during the closing control by the torque fluctuation determination means 168 in addition to the transmission speed 48 being determined to be in the maximum deceleration state by the maximum deceleration determination means 166. The duty-down control command signal S _T ″ is output to the hydraulic control circuit 100 when starting the vehicle after stopping the vehicle, provided that it is determined that the input torque T _IN has not changed. As a result, the transmission belt 48 is kept in its most decelerated state.

The torque fluctuation determining means 168, when the closing control in the predetermined vehicle speed V 'following vehicle condition is being executed, whether the variation in the input torque T _IN is inputted to the drive pulley 42 is generated, for example, A determination is made based on whether garage shift has been executed and whether neutral control has been executed. In other words, it determines whether the vehicle driving apparatus 10 is a variation in the input torque T _IN is inputted to the drive pulley 42 on the basis of whether or not switched between the power transmission interrupted state and power transmitting state occurs To do. The torque variation determination unit 168, the vehicle drive device 10 determines that change in the input torque T _IN input and is switched to the drive pulley 42 between the power transmission interrupted state and power transmitting state occurs .

More specifically, the torque fluctuation determining means 168, when the closing control in the predetermined vehicle speed V 'following vehicle state is executed, the garage shift command signal S _A by the engagement control means 162 hydraulic it is determined whether not output to the control circuit 100, when the garage shifting command signal S _a is not output to the hydraulic control circuit 100 does not occur is a change in the input torque T _iN is inputted to the drive pulley 42 while it is determined that, when the garage shifting command signal S _a is output is determined that the variation in the input torque T _iN is inputted to the drive pulley 42 has occurred.

Further, the torque fluctuation determining means 168 is configured such that the neutral control command signal S _A ″ is output from the hydraulic control circuit 100 by the engagement control means 162 when the closing control is being executed in a vehicle state of a predetermined vehicle speed V ′ or less. And when the neutral control command signal S _A ″ is not output to the hydraulic control circuit 100, it is determined that the input torque T _IN input to the drive pulley 42 has not changed. On the other hand, when the neutral control command signal S _A ″ is output, it is determined that the input torque T _IN input to the driving pulley 42 has changed.

While the belt back determination flag Fbelt is turned ON by an electronic control unit 50 when the change in the input torque T _IN is inputted to the drive pulley 42 is determined not caused by the torque fluctuation determining means 168, the torque fluctuation belt back determination flag Fbelt is turned OFF by the electronic control unit 50 when the change in the input torque T _iN is inputted to the drive pulley 42 is determined to have occurred by determining means 168.

The shift control means 152 outputs the duty down control command signal S _T ″ to the hydraulic control circuit 100 if the belt return determination flag Fbelt is ON when the vehicle starts after the vehicle stops. while to maintain the highest speed reduction state of the transmission belt 48, running the closing control by outputting a control command signal S _{T 'confinement} said to the hydraulic control circuit 100 when the belt return determination flag Fbelt is turned OFF To do.

  FIG. 8 shows a main part of the control operation of the electronic control unit 50, that is, for suppressing the occurrence of belt slip when starting the vehicle when it is determined that the speed ratio γ of the continuously variable transmission 18 is the maximum speed ratio γmax. It is a flowchart explaining the control operation, and is repeatedly executed with an extremely short cycle time of about several milliseconds to several tens of milliseconds, for example.

  First, in a step (hereinafter, step is omitted) S1 corresponding to the most deceleration determination means 166, the speed ratio γ of the continuously variable transmission 18 becomes the maximum speed ratio γmax when the vehicle is stopped while the closing control is performed. Whether or not the transmission belt 48 is in the maximum deceleration state, for example, the gear ratio γ is already the maximum gear ratio γmax at a vehicle speed V that exceeds a predetermined vehicle speed V ′ during vehicle deceleration traveling, for example. Judgment is made based on whether or not the vehicle is stopped in the state.

If the determination in S1 is affirmative, the belt return determination flag Fbelt is turned ON, and in S2 corresponding to the torque fluctuation determination means 168, the closing control is executed in a vehicle state of a predetermined vehicle speed V 'or less. when you are, the garage shift command signal S _A whether not output to the hydraulic control circuit 100 is determined.

If the determination in S2 is negative, the belt return determination flag Fbelt is turned off in S3. If the determination is affirmative, the belt return determination flag Fbelt is turned on as it is and corresponds to the torque fluctuation determination means 168. In S <b> 4, it is determined whether or not the neutral control command signal S _A ″ has not been output to the hydraulic control circuit 100 when the closing control is being executed in a vehicle state of a predetermined vehicle speed V ′ or less.

If the determination in S4 is negative, the belt return determination flag Fbelt is turned off in S5. If the determination is affirmative, the belt return determination flag Fbelt is turned on as it is and S6 corresponding to the shift control means 152 is set. When the vehicle starts after the vehicle stops, the duty down control command signal S _T ″ is output to the hydraulic control circuit 100, and the transmission belt 48 is maintained in the most decelerated state.

If the determination in S1 is negative and the belt return determination flag Fbelt is OFF, or following S3 or S5, in S7 corresponding to the shift control means 152, the vehicle start after the vehicle stops. At this time, the closing control command signal S _T ′ is output to the hydraulic control circuit 100 to execute the closing control.

As described above, according to this embodiment, it is determined by the most deceleration determination means 166 that the transmission belt 48 is in the most deceleration state when the vehicle is stopped and the torque fluctuation determination means 168 performs the closing control during the closing control. on condition that variation in the input torque T _iN is input is determined not to occur, the maximum speed ratio speed ratio γ of the continuously variable transmission 18 .gamma.max the time of vehicle start after the vehicle stops as will be maintained, since the supply and discharge of hydraulic oil is controlled, fluctuation in the input torque T _iN is input to the driving pulley 42 at the time of closing control is generated transmission to the driving side hydraulic cylinder 42c by the speed change control means 152 When the belt 48 is out of the maximum deceleration state, the hydraulic oil is not supplied to or discharged from the drive side hydraulic cylinder 42c to bring the transmission belt 48 into the maximum deceleration state. The occurrence of slippage is prevented from. Therefore, the occurrence of belt slip is suppressed when the vehicle starts when it is determined that the speed ratio γ of the continuously variable transmission 18 is the maximum speed ratio γmax.

In addition, according to the present embodiment, the torque fluctuation determining means 168 inputs the driving device 10 to the driving pulley 42 based on whether or not the vehicle drive device 10 is switched between the power transmission cut-off state and the power transmission enabled state. that is intended to whether variation in the input torque T _iN is generated is determined and inputted to the drive pulley 42 and is switched between the vehicle drive device 10 and the power transmission interrupted state and power transmitting state Since it is determined that the input torque _TIN has fluctuated, when the power transmission of the vehicle drive device 10 is in the neutral state, the vehicle starts to move with the release of the foot brake depending on the vehicle state such as a hill road. When the pulley 42 rotates and the transmission belt 48 is out of the most decelerated state, the drive side hydraulic cylinder 42 for bringing the transmission belt 48 into the most decelerated state. Supply and discharge of hydraulic fluid is not performed for the occurrence of belt slippage is prevented.

  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 input shaft rotation speed N _IN exemplified as the rotation speed of the predetermined rotation member and the target input shaft rotation speed N _IN ^* related thereto are replaced with the input shaft rotation speed N _IN etc. The engine rotational speed _NE and the related target engine rotational speed _NE ^* may be used, or the turbine rotational speed _NT and the related target turbine rotational speed _NT ^* may be used. Accordingly, a rotational speed sensor such as the input shaft rotational speed sensor 56 may be appropriately provided in accordance with the rotational speed that needs to be controlled.

  In the above-described embodiment, the torque converter 14 provided with the lock-up clutch 26 is used as the fluid transmission device. However, the lock-up clutch 26 is not necessarily provided. In addition, other fluid type power transmission devices such as a fluid coupling (fluid coupling) having no torque amplification function may be used.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

1 is a skeleton diagram illustrating a vehicle drive 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. 3 is a hydraulic circuit diagram showing a main part relating to belt clamping pressure control of a continuously variable transmission, gear ratio control, and engagement hydraulic control of a forward clutch or reverse brake accompanying operation of a shift lever in the hydraulic control circuit. It is a figure which shows an example of the shift map used when calculating | requiring a target input rotational speed in the shift control of a continuously variable transmission. It is a figure which shows an example of the required hydraulic pressure map which calculates | requires required hydraulic pressure according to gear ratio etc. in the clamping pressure control of a continuously variable transmission. This is a relationship obtained and stored in advance between the gear ratio and the thrust ratio with the vehicle speed as a parameter. It is a functional block diagram explaining the principal part of the control function of the electronic control apparatus of FIG. The main part of the control operation of the electronic control unit of FIG. 2, that is, the control operation for suppressing the occurrence of belt slip when starting the vehicle when it is determined that the speed ratio of the continuously variable transmission is at the maximum speed ratio will be described. It is a flowchart.

Explanation of symbols

12: Engine (power source for running)
18: continuously variable transmission 24: driving wheel 42: driving pulley 42c: driving hydraulic cylinder (driving hydraulic actuator)
46: driven pulley 48: transmission belt (belt)
50: Electronic control device (shift control device)
114: Transmission ratio control valve UP (transmission control valve)
116: Transmission ratio control valve DN (transmission control valve)
152: Shift control means (startup shift control means)
166: Maximum deceleration determination means 168: Torque fluctuation determination means

Claims (2)

In a vehicle in which a continuously variable transmission having a driving pulley and a driven pulley and a belt wound around both pulleys is disposed on a power transmission path between a driving power source and driving wheels, the driving side A drive-side hydraulic actuator for changing the groove width of the pulley, and a shift control valve for changing the groove width of the drive-side pulley by controlling supply and discharge of hydraulic oil to and from the drive-side hydraulic actuator, and having a predetermined vehicle speed In the vehicle state exceeding the above, the hydraulic control actuator controls the supply and discharge of hydraulic fluid to the drive side hydraulic actuator to shift the continuously variable transmission, while in the vehicle state below a predetermined vehicle speed, the drive is controlled by the shift control valve. A transmission control device for a continuously variable transmission for a vehicle in which hydraulic oil is confined in a side hydraulic actuator and a transmission ratio of the continuously variable transmission is set to a predetermined transmission ratio,
A minimum deceleration determination means for determining whether or not the speed ratio of the continuously variable transmission is at the minimum speed side gear ratio when the vehicle is stopped;
Whether or not a change has occurred in the input torque input to the drive-side pulley when the hydraulic oil is confined in the drive-side hydraulic actuator by the shift control valve in a vehicle state below the predetermined vehicle speed Torque fluctuation judging means for judging whether
It is determined that the speed reduction ratio of the continuously variable transmission is at the lowest speed side speed ratio by the most deceleration determination means, and the input torque input to the driving pulley is not changed by the torque fluctuation determination means. On the condition that it is determined, when starting the vehicle, the shift control valve allows the hydraulic oil to be supplied to and discharged from the drive side hydraulic actuator so that the transmission gear ratio of the continuously variable transmission is maintained at the lowest speed transmission gear ratio. A shift control device for a continuously variable transmission for a vehicle, comprising: a start shift control means for controlling the vehicle.   The torque fluctuation determining means is configured to determine whether the power transmission path between the driving power source and the continuously variable transmission has been switched between a power transmission cut-off state and a power transmission enabled state. It is determined whether or not the input torque input to the pulley has fluctuated. When the power transmission path is switched between the power transmission cutoff state and the power transmission possible state, the input torque is input to the driving pulley. The shift control apparatus for a continuously variable transmission for a vehicle according to claim 1, wherein it is determined that the input torque fluctuates.

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