JP7179408B2 - gearbox controller - Google Patents

Description

The present invention relates to a control device for a transmission.

A CVT (Continuously Variable Transmission) is widely known as a transmission mounted on a vehicle.

The CVT has a configuration in which an endless belt is wound around a primary pulley on the input side and a secondary pulley on the output side. When torque from a drive source such as an engine is input to the primary pulley, the torque is transmitted from the primary pulley to the belt due to the frictional force between the primary pulley and the belt, and the frictional force between the secondary pulley and the belt , the torque is transmitted from the belt to the secondary pulley.

Both the primary pulley and the secondary pulley have a fixed sheave and a movable sheave disposed opposite to the fixed sheave with a belt interposed therebetween, and a movable sheave provided movably in the facing direction, and a movable sheave on the opposite side of the movable sheave from the fixed sheave. and a piston that forms a piston chamber (oil chamber) with the movable sheave. The clearance between the fixed sheave and the movable sheave is changed by controlling the hydraulic pressure acting on each movable sheave of the primary pulley and the secondary pulley. Along with this, the winding diameter of the belt around the primary pulley changes, the interval between the fixed sheave and the movable sheave of the secondary pulley changes, and the winding diameter of the belt around the secondary pulley changes. As a result, the gear ratio (pulley ratio) changes steplessly and continuously.

JP-A-2004-176890

In CVT transmission control, a target gear ratio is set, and a control pressure corresponding to the deviation between the target gear ratio and the actual gear ratio, that is, the actual gear ratio, acts on each movable sheave of the primary pulley and the secondary pulley. A hydraulic command value is set. The operation of valves included in the hydraulic circuit is controlled so that the control pressure acts on the movable sheaves of the primary pulley and the secondary pulley.

However, conventional shift control has room for various improvements, and an improvement in followability is desired.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a transmission control device capable of improving followability of shift control.

In order to achieve the above object, a transmission control device according to the present invention provides an endless pulley having a fixed sheave and a movable sheave whose distance from the fixed sheave is changed by hydraulic pressure supplied to an oil chamber from a hydraulic circuit. A control device for a transmission having a configuration in which a belt is wound around, and a hydraulic pressure for controlling the position of a movable sheave, which is responsive to the deviation between the target transmission gear ratio and the actual gear ratio of the transmission. a control pressure setting means for setting the control pressure, and a dischargeable pressure estimation means for estimating the dischargeable pressure of the oil pump that generates the original pressure in the hydraulic circuit in consideration of the change in the volume of the oil chamber due to the movement of the movable sheave. and control pressure limiting means for limiting the control pressure set by the control pressure setting means based on the dischargeable pressure estimated by the dischargeable pressure estimation means.

According to this configuration, the control pressure is set according to the deviation between the target gear ratio of the transmission and the actual gear ratio. By supplying the hydraulic pressure of this control pressure to the movable sheave, the actual gear ratio can be brought closer to the target gear ratio.

There is an upper limit to the control pressure due to the limited capacity of the oil pump to generate the original pressure of the hydraulic circuit. If the control pressure is set above the upper limit, the deviation between the target gear ratio and the actual gear ratio will not decrease. increase.

Therefore, the dischargeable pressure of the oil pump that generates the original pressure in the hydraulic circuit is estimated, and the control pressure is limited based on the dischargeable pressure. As a result, even if the setting of the control pressure includes an integral calculation for ensuring followability of the control, it is possible to suppress the accumulation of the deviation between the target gear ratio and the actual gear ratio. Therefore, it is possible to improve the followability of the speed change control.

According to the present invention, it is possible to improve the followability of shift control.

1 is a skeleton diagram showing the configuration of a drive system of a vehicle; FIG. 1 is a block diagram showing the configuration of a control system according to one embodiment of the present invention; FIG. 3 is a block diagram showing the configuration of a sheave speed change controller; FIG. 3 is a block diagram showing the configuration of an upper limit guard amount setting unit; FIG. 4 is a flow chart showing the flow of processing executed by a sheave speed change controller; FIG. 4 is a diagram showing an example of temporal changes in an I control value, control pressure, and actual gear ratio;

BEST MODE FOR CARRYING OUT THE INVENTION Below, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Vehicle drive system>
FIG. 1 is a skeleton diagram showing the configuration of the driving system of the vehicle 1. As shown in FIG.

A vehicle 1 is an automobile having an engine 2 as a drive source.

The engine 2 is provided with an electronic throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 2, an injector (fuel injection device) for injecting fuel into the intake air, and a spark plug for generating electrical discharge in the combustion chamber. It is The engine 2 is also provided with a starter for starting the engine. The power of the engine 2 is transmitted to a differential gear 5 via a torque converter 3 and a belt-type CVT (Continuously Variable Transmission) 4, and from the differential gear 5 via left and right drive shafts 6L and 6R. They are transmitted to the left and right driving wheels 7L and 7R, respectively.

The torque converter 3 is a torque converter with a lockup mechanism, and includes a front cover 11 , a pump impeller 12 , a turbine runner 13 and a lockup clutch (lockup piston) 14 . A crankshaft of the engine 2 is connected to the front cover 11, and the front cover 11 rotates integrally with the crankshaft. The pump impeller 12 is arranged on the opposite side of the front cover 11 from the engine side. The pump impeller 12 is provided so as to be rotatable together with the front cover 11 . The turbine runner 13 is arranged between the front cover 11 and the pump impeller 12 and is rotatable about a rotation axis shared with the front cover 11 . Lockup clutch 14 is arranged between front cover 11 and turbine runner 13 .

The lockup clutch 14 has a differential pressure between the oil pressure in the release side oil chamber 15 between the lockup clutch 14 and the front cover 11 and the oil pressure in the engagement side oil chamber 16 between the lockup clutch 14 and the pump impeller 12. is engaged/released by That is, when the hydraulic pressure in the disengagement side oil chamber 15 is higher than the hydraulic pressure in the engagement side oil chamber 16, the lockup clutch 14 is separated from the front cover 11 due to the pressure difference, and the lockup clutch 14 is released and locked. It becomes an up-off state (released state). When the oil pressure in the engagement side oil chamber 16 is higher than the oil pressure in the release side oil chamber 15, the lockup clutch 14 is pressed against the front cover 11 due to the difference in pressure, and the lockup clutch 14 is engaged. It will be in an up-on state (fastened state).

In the lockup off state, when the E/G output shaft is rotated, the pump impeller 12 rotates. Rotation of the pump impeller 12 causes a flow of oil from the pump impeller 12 towards the turbine runner 13 . This oil flow is received by the turbine runner 13 to rotate the turbine runner 13 . At this time, an amplifying action of the torque converter 3 occurs, and the turbine runner 13 generates power larger than the power (torque) of the E/G output shaft.

In the lockup ON state, when the E/G output shaft is rotated, the E/G output shaft, pump impeller 12 and turbine runner 13 rotate together.

An oil pump 8 is provided between the torque converter 3 and the CVT 4 . The oil pump 8 is a mechanical oil pump, and the pump shaft is provided so as to rotate integrally with the pump impeller 12 of the torque converter 3 . As a result, when the pump impeller 12 is rotated by the power of the engine 2, the pump shaft of the oil pump 8 is rotated, and the oil pump 8 generates hydraulic pressure.

CVT 4 transmits power input from torque converter 3 to differential gear 5 . The CVT 4 includes an input shaft (input shaft) 21 , an output shaft (output shaft) 22 , a belt transmission mechanism 23 and a forward/reverse switching mechanism 24 .

The input shaft 21 is connected to the turbine runner 13 of the torque converter 3 and integrally rotatable around the same rotational axis as the turbine runner 13 .

The output shaft 22 is arranged parallel to the input shaft 21 . An output gear 25 is supported on the output shaft 22 so as not to rotate relative to it.

The belt transmission mechanism 23 includes a primary shaft 31 and a secondary shaft 32 . The primary shaft 31 and the secondary shaft 32 are arranged on the same axis as the input shaft 21 and the output shaft 22, respectively.

The belt transmission mechanism 23 has a configuration in which an endless belt 35 is wound around a primary pulley 33 supported by the primary shaft 31 and a secondary pulley 34 supported by the secondary shaft 32 .

The primary pulley 33 is arranged to face a fixed sheave 41 fixed to the primary shaft 31 with the belt 35 interposed between the fixed sheave 41 and a movable sheave supported by the primary shaft 31 so as to be movable in its axial direction and not relatively rotatable. 42. A piston 43 fixed to the primary shaft 31 is provided on the side opposite to the fixed sheave 41 with respect to the movable sheave 42 , and a piston chamber (oil chamber) 44 is formed between the movable sheave 42 and the piston 43 . there is

The secondary pulley 34 is opposed to a fixed sheave 45 fixed to the secondary shaft 32 with the belt 35 interposed therebetween, and is supported by the secondary shaft 32 so as to be movable in the axial direction thereof and not relatively rotatable. A movable sheave 46 is provided. A piston 47 fixed to the secondary shaft 32 is provided on the opposite side of the movable sheave 46 from the fixed sheave 45 , and a piston chamber 48 is formed between the movable sheave 46 and the piston 47 .

The movement of the movable sheave 42 of the primary pulley 33 continuously changes the groove width, which is the interval between the fixed sheave 41 and the movable sheave 42 . The movement of the movable sheave 46 of the secondary pulley 34 continuously changes the groove width, which is the interval between the fixed sheave 45 and the movable sheave 46 . By continuously changing the groove widths of the primary pulley 33 and the secondary pulley 34, the winding diameter of the belt 35 around the primary pulley 33 and the secondary pulley 34 can be changed, and the transmission gear ratio (pulley ratio) can be changed steplessly. can be changed continuously.

Although not shown, a bias spring is interposed between the movable sheave 46 and the piston 47 to apply initial clamping pressure (initial thrust) to the belt 35 . The elastic force of the bias spring urges the movable sheave 46 and the piston 47 away from each other.

The forward/reverse switching mechanism 24 is interposed between the input shaft 21 and the primary shaft 31 of the belt transmission mechanism 23 . The forward/reverse switching mechanism 24 includes a planetary gear mechanism 51, a clutch C1 and a brake B1.

Planetary gear mechanism 51 includes carrier 52 , sun gear 53 and ring gear 54 .

The carrier 52 is fitted onto the input shaft 21 so as to be relatively rotatable. Carrier 52 rotatably supports a plurality of pinion gears 55 . A plurality of pinion gears 55 are arranged on the circumference.

The sun gear 53 is supported by the input shaft 21 so as not to rotate relative to it, and is arranged in a space surrounded by a plurality of pinion gears 55 . The gear teeth of the sun gear 53 mesh with the gear teeth of each pinion gear 55 .

The ring gear 54 is provided such that its rotational axis coincides with the axial center of the primary shaft 31 . A primary shaft 31 of the belt transmission mechanism 23 is connected to the ring gear 54 . The gear teeth of the ring gear 54 are formed so as to collectively surround the plurality of pinion gears 55 and mesh with the gear teeth of each pinion gear 55 .

The clutch C1 is switched by hydraulic pressure between an engaged state (ON) in which the carrier 52 and the sun gear 53 are directly connected (coupled so as to be rotatable together) and a released state (OFF) in which the direct connection is released.

The brake B1 is provided between the carrier 52 and the transmission case that accommodates the torque converter 3 and the CVT 4, and is hydraulically engaged (on) to brake the carrier 52 and released (to allow the carrier 52 to rotate). off).

A shift lever (select lever) is disposed in the vehicle interior of the vehicle 1 at a position that can be operated by the driver. In the movable range of the shift lever, for example, a P (parking) position, an R (reverse) position, an N (neutral) position, and a D (drive) position are arranged in this order.

When the shift lever is in the P position, both the clutch C1 and the brake B1 are released and the parking lock gear (not shown) is fixed, thereby forming the P range, which is one of the transmission ranges of the CVT 4. be done. When the shift lever is in the N position, both the clutch C1 and the brake B1 are disengaged and the parking lock gear is not fixed, thereby forming the N range, which is one of the shift ranges of the CVT 4. When both the clutch C1 and the brake B1 are released, the input shaft 21 and the sun gear 53 idle, and the power of the engine 2 is not transmitted to the driving wheels 7L, 7R.

When the shift lever is in the D position, the brake B1 is engaged and the clutch C1 is released, thereby forming a forward range, which is one of the shift ranges of the CVT4. In the forward range, when the power of the engine 2 is input to the input shaft 21, the sun gear 53 rotates integrally with the input shaft 21 while the carrier 52 remains stationary. Therefore, the rotation of the sun gear 53 is transmitted to the ring gear 54 after being reversed and decelerated. As a result, the ring gear 54 rotates, and the primary shaft 31 and the primary pulley 33 of the belt transmission mechanism 23 rotate together with the ring gear 54 . Rotation of the primary pulley 33 is transmitted to the secondary pulley 34 via the belt 35 to rotate the secondary pulley 34 and the secondary shaft 32 . The output shaft 22 and the output gear 25 rotate integrally with the secondary shaft 32 . The output gear 25 meshes with the differential gear 5 (the input gear of the differential gear 5). When the output gear 25 rotates, the drive shafts 6L, 6R extending laterally from the differential gear 5 rotate, and the drive wheels 7L, 7R rotate, thereby causing the vehicle 1 to move forward.

When the shift lever is in the R position, the R range, which is one of the shift ranges of the CVT 4, is configured by disengaging the brake B1 and engaging the clutch C1. In the R range, when the power of engine 2 is input to input shaft 21 , carrier 52 and sun gear 53 rotate integrally with input shaft 21 . Therefore, the rotation of the sun gear 53 is transmitted to the ring gear 54 without reversing the rotation direction. As a result, the ring gear 54 rotates, and the primary shaft 31 and the primary pulley 33 of the belt transmission mechanism 23 rotate together with the ring gear 54 . Rotation of the primary pulley 33 is transmitted to the secondary pulley 34 via the belt 35 to rotate the secondary pulley 34 and the secondary shaft 32 . The output shaft 22 and the output gear 25 rotate integrally with the secondary shaft 32 . When the output gear 25 rotates, the drive shafts 6L, 6R extending laterally from the differential gear 5 rotate, and the drive wheels 7L, 7R rotate, thereby causing the vehicle 1 to move backward.

<Vehicle control system>
FIG. 2 is a block diagram showing the configuration of the control system of the vehicle 1. As shown in FIG.

The vehicle 1 is equipped with an ECU (Electronic Control Unit) including a microcomputer (microcontroller unit). A microcomputer includes, for example, a CPU, a nonvolatile memory such as a flash memory, and a volatile memory such as a DRAM (Dynamic Random Access Memory). Although only one ECU 101 for controlling the torque converter 3 and the CVT 4 is shown in FIG. ing. A plurality of ECUs including the ECU 101 are connected so as to be capable of two-way communication using a CAN (Controller Area Network) communication protocol. Further, the ECU 101 is connected to sensors necessary for control, for example, pressure sensors 102 for detecting hydraulic pressure (actual pressure) supplied to the movable sheave 42 of the primary pulley 33 and the movable sheave 47 of the secondary pulley 34, respectively. .

The ECU 101 functions as a sheave shift controller for shift control that controls the gear ratio of the CVT 4 . In other words, the ECU 101 functions as a sheave shift controller that controls the gear ratio of the CVT 4 .

In shift control by this function, first, a target rotation speed is set according to the accelerator opening and the vehicle speed based on the shift map. The shift map is a map that defines the relationship between the accelerator opening degree, the vehicle speed, and the target rotation speed, and is stored in the non-volatile memory of the ECU 101, for example. Information on the accelerator opening and the vehicle speed is transmitted from an engine ECU that controls the engine 2 to the ECU 101, for example. When the target rotation speed is set, a target gear ratio is set so that the rotation speed input to the input shaft 21 matches the target rotation speed.

Next, the deviation E between the target gear ratio and the actual gear ratio, which is the actual gear ratio, is obtained, and the respective control pressures of the primary pulley 33 and the secondary pulley 34 are set according to the deviation E. Valves included in the hydraulic circuit 111 for supplying hydraulic pressure to each part of the torque converter 3 and the CVT 4 so that these control pressures act on the movable sheave 42 of the primary pulley 33 and the movable sheave 46 of the secondary pulley 34 are controlled.

The actual gear ratio is obtained, for example, by dividing the rotation speed of primary pulley 33 by the rotation speed of secondary pulley 34 . The rotation speed of the primary pulley 33 is calculated from the detection signal of the primary rotation sensor that outputs a pulse signal synchronized with the rotation of the primary shaft 31 as a detection signal. Further, the number of rotations of the secondary pulley 34 is calculated from a detection signal of a secondary rotation sensor that outputs a pulse signal synchronized with the rotation of the secondary shaft 32 as a detection signal.

<Sheave speed change controller>
FIG. 3 is a block diagram showing the configuration of the sheave shift controller.

The sheave shift controller includes a deviation calculator 121 that obtains a deviation (control deviation) E between the target gear ratio and the actual gear ratio, and a P control corresponding to the deviation E by a P action (proportional action) at a P (proportional) gain Kp. an I control unit 123 that outputs an I control value corresponding to the deviation E by an I action (integral action) at the I (integral) gain Ki; and a D (differential) gain Kd: A D control unit 124 that outputs a D control value corresponding to the deviation E by a D operation (differential operation), and a control pressure output unit 125 that outputs the sum of the P control value, the I control value, and the D control value as a control pressure. , an upper limit limiter 126 that limits the upper limit of the control pressure output by the control pressure output unit 125 and outputs a guard control pressure whose upper limit is limited, and a control pressure upper limit guard that is used for the limit by the upper limit limiter 126 and an upper limit guard amount setting unit 127 for setting the amount.

Further, the sheave speed change controller includes a windup amount calculator 128 that subtracts the guard control pressure output by the upper limit unit 126 from the control pressure output by the control pressure output unit 125 and outputs the subtracted value as a windup amount; An amplification section 129 that amplifies the windup amount output by the windup amount calculation section 128 with a predetermined windup gain is substantially provided. Then, the I control unit 123 calculates the I control value by integrating the difference between the multiplied value obtained by multiplying the deviation E by the I gain Ki and the amplified value of the windup amount output from the amplifying unit 129 .

<Upper limit guard amount setting part>
FIG. 4 is a block diagram showing the configuration of the upper limit guard amount setting section 127. As shown in FIG.

The upper limit guard amount setting unit 127 includes a source pressure estimating unit 131 that estimates the source pressure of the hydraulic circuit 111 from the actual pressure detected by the pressure sensor 102 and outputs the estimated value (original pressure estimated value); A limit value calculation unit 132 that calculates a limit value according to the amount of change in volume of the piston chambers (oil chambers) 44 and 48 of the primary pulley 33 and the secondary pulley 34 from the amount of change in , and the source pressure of the hydraulic circuit 111 is generated. A subtraction unit 133 that subtracts the limit value calculated by the limit value calculation unit 132 from the pump shaft rotation speed of the oil pump 8 and outputs the subtracted value, and the primary pulley 33 and the secondary pulley 34 (movable sheaves 42 and 46) A pump dischargeable pressure estimation unit 134 that estimates and outputs the dischargeable pressure of the oil pump 8 from the oil temperature of the supplied hydraulic oil and the subtraction value output by the subtraction unit 133, and the source pressure output by the source pressure estimation unit 131 A minimum value selection unit 135 that selects and outputs the minimum value between the estimated value and the dischargeable pressure estimated by the pump dischargeable pressure estimation unit 134, and the windup amount output by the windup amount calculation unit 128 (see FIG. 3) and 0 to determine whether or not the windup amount is a value greater than 0; and a selection output unit 137 that selects one of the dischargeable pressure output by 134 and the minimum value output by the minimum value selection unit 135 and outputs it as the upper limit guard amount.

When the oil pressure (actual pressure) supplied to the movable sheaves 42 and 46 does not follow the control pressure due to a decrease in the original pressure due to disturbance or the like, the actual pressure detected by the pressure sensor 102 decreases. Therefore, the source pressure estimator 131 can estimate the source pressure from the hydraulic pressure detected by the pressure sensor 102 .

The limit value calculator 132 calculates the fluid inflow amount dQpri/dt, which is the inflow amount of hydraulic oil into the piston chamber 44 of the primary pulley 33, according to the following equation (1).

ただし、Apri：プライマリプーリ３３の可動シーブ４２の受圧面積
dPpri/dt：プライマリプーリ３３の可動シーブ４２の移動速度

However, Apri: the pressure receiving area of the movable sheave 42 of the primary pulley 33
dPpri/dt: Moving speed of movable sheave 42 of primary pulley 33

Since the position of the movable sheave 42 corresponds to the rotation speed ratio between the primary pulley 33 and the secondary pulley 34, that is, the gear ratio, the moving speed dPpri/dt of the movable sheave 42 corresponds to the respective rotation speeds of the primary pulley 33 and the secondary pulley 34. can be calculated from

ただし、Qpump：オイルポンプ８の単位回転数あたりの吐出能力 Then, the pump rotation speed dNpri/dt required to generate the fluid inflow amount dQpri/dt is calculated according to the following equation (2).

However, Qpump: Discharge capacity per unit revolution of the oil pump 8

Further, in the limit value calculation unit 132, the fluid inflow amount dQsec/dt, which is the inflow amount of hydraulic oil into the piston chamber 48 of the secondary pulley 34, is calculated according to the following equation (3).

ただし、Asec：セカンダリプーリ３４の可動シーブ４６の受圧面積
dPsec/dt：セカンダリプーリ３４の可動シーブ４６の移動速度

where Asec is the pressure receiving area of the movable sheave 46 of the secondary pulley 34
dPsec/dt: Moving speed of movable sheave 46 of secondary pulley 34

Since the position of the movable sheave 46 corresponds to the rotation speed ratio between the primary pulley 33 and the secondary pulley 34, that is, the gear ratio, the moving speed dPsec/dt of the movable sheave 46 corresponds to the rotation speed of the primary pulley 33 and the secondary pulley 34. can be calculated from

Then, the pump rotation speed dNsec/dt required to generate the fluid inflow amount dQsec/dt is calculated according to the following equation (2).

Therefore, the pump shaft rotation speed (pump rotation speed) dN/dt required when the hydraulic pressure supplied to the movable sheaves 42, 46 is changed by the shift control described below is given by the following equation (5). , the pump rotation speed dNpri/dt required for volume change due to movement of the movable sheave 42 of the primary pulley 33 and the pump rotation speed dNsec/dt required for volume change due to movement of the movable sheave 46 of the secondary pulley 34 are added. value.

Then, the pump shaft rotation speed dN/dt is set as a limit value corresponding to the change in volume of the primary pulley 33 and the secondary pulley 34, and the pump dischargeable pressure estimator 134 calculates the relevant value from the pump shaft rotation speed of the oil pump 8. By estimating the dischargeable pressure of the oil pump 8 based on the value obtained by subtracting the limit value, it is possible to accurately estimate the dischargeable pressure of the oil pump 8 . As can be understood from the above formulas (1) and (3), the volume change on the side from which the hydraulic oil flows does not affect the performance of the oil pump 8, so the limit value (pump shaft rotation speed dN /dt).

<Speed change control>
FIG. 5 is a flow chart showing the flow of processing executed by the sheave speed change controller.

For speed change control, the ECU 101, which functions as a sheave change controller, executes the process shown in FIG. 5 at each predetermined control cycle.

In this process, first, the P control value by the P action at the P gain Kp, the I control value by the I action at the I gain Ki, and the D control value by the D action at the D gain Kd are set, and these P control values are set. A control pressure is calculated by adding the value, the I control value, and the D control value (step S1).

Next, it is determined by the windup determination unit 136, that is, whether or not the windup amount (previous windup amount) calculated during control one cycle before the current control cycle is a value greater than 0. (Step S2).

If the previous windup amount is greater than 0 (YES in step S2), the upper limit guard amount setting unit 127 sets the upper limit guard amount to the minimum value output by the minimum value selection unit 135, that is, the source pressure estimating unit 131 The smaller of the source pressure estimated value, which is the value of the estimated source pressure, and the dischargeable pressure estimated by the pump dischargeable pressure estimator 134 is determined (step S3). If the previous windup amount is greater than 0, it means that the control pressure calculated during control one cycle before the current control cycle exceeds the upper limit guard amount, and the control pressure is saturated. .

On the other hand, if the previous windup amount is 0 or less (NO in step S2), it means that the control pressure calculated during the control one cycle before the current control cycle does not exceed the upper limit guard amount. is not saturated. In this case, the upper limit guard amount setting unit 127 sets the upper limit guard amount to the dischargeable pressure estimated by the pump dischargeable pressure estimation unit 134 (step S4).

After setting the upper limit guard amount, the upper limit limiter 126 compares the set upper limit guard amount with the control pressure output by the control pressure output unit 125, and the smaller value of them is used as the guard control pressure. It is output (step S5).

After that, the windup amount is calculated by the windup amount calculator 128 for use in the process in the next control cycle (step S6).

Then, the windup amount output by the windup amount calculator 128 is fed back to the I operation (step S7), and the series of processes is terminated.

<Effect>
As described above, the control pressure is set according to the deviation E between the target gear ratio of the CVT 4 and the actual gear ratio. By supplying the hydraulic pressure of this control pressure to the movable sheave 42 of the primary pulley 33 and the movable sheave 46 of the secondary pulley 34, the actual gear ratio can be brought closer to the target gear ratio.

Since the ability of the oil pump 8 to generate the original pressure of the hydraulic circuit 111 is limited, the control pressure has an upper limit. If the control pressure is set to exceed its upper limit, the deviation E between the target speed ratio and the actual speed ratio does not decrease, and the multiplied value obtained by multiplying the deviation E by the I gain Ki results in the calculation of the I control value by the I operation. That is, when used for integral calculation, the deviation E accumulates and increases.

Therefore, the original pressure generated in the hydraulic circuit 111 and the dischargeable pressure of the oil pump 8 that generates the original pressure in the hydraulic circuit 111 are estimated, and the upper limit of the control pressure is limited to the estimated original pressure or the dischargeable pressure. Therefore, the smaller the source pressure estimated value or the dischargeable pressure is, the smaller the guard control pressure, which is the control pressure after being limited by the source pressure estimated value or the dischargeable pressure, is limited to a smaller value. The larger the difference between the control pressure and the guard control pressure, the larger the windup amount obtained by subtracting the guard control pressure from the control pressure. The I control value calculated by integrating the deviation from the amplified value of the windup amount output by is a small value. As a result, as can be understood by comparing the solid line with the dashed line and the two-dot chain line shown in FIG. Compared to the construction in which the windup amount obtained by subtracting the fixed upper limit amount from the pressure is fed back to the I operation, the construction of the sheave speed change controller described above allows the I control value to be suppressed to a small value. As a result, the control pressure can be restricted more strongly, and the accumulation of the deviation E between the target speed ratio and the actual speed ratio can be suppressed.

<Modification>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other forms.

For example, in the above-described embodiment, the ECU 101 that controls the CVT 4 was taken up. However, the transmission to be controlled by the ECU 101 is not limited to the CVT 4, and may be a power split type continuously variable transmission. A power split type continuously variable transmission, for example, is equipped with a belt-type continuously variable transmission mechanism that changes the power steplessly by changing the gear ratio, and divides the power into two paths between the input shaft and the output shaft. It is a transmission that can be transmitted by

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

4: CVT (transmission)
8: Oil pump 33: Primary pulley (pulley)
35: Belt 41: Fixed Sheave 42: Movable Sheave 101: ECU (control device)
111: hydraulic circuit 121: deviation calculator (control pressure setting means)
122: P control section (control pressure setting means)
123: I control unit (control pressure setting means)
124: D control section (control pressure setting means)
125: Control pressure output unit (control pressure setting means)
126: Upper limit limiter (control pressure limiter)
134: Pump dischargeable pressure estimation unit (dischargeable pressure estimation means)

Claims (1)

A control device for a transmission having a configuration in which an endless belt is wound around a pulley having a fixed sheave and a movable sheave whose spacing from the fixed sheave is changed by hydraulic pressure supplied to an oil chamber from a hydraulic circuit. and
In order to control the position of the movable sheave, the control pressure corresponding to the deviation between the target gear ratio of the transmission and the actual gear ratio is supplied from the hydraulic circuit to the oil chamber and is supplied to the movable sheave. a control pressure setting means for setting the control pressure acting on the
Dischargeable pressure estimating means for estimating a dischargeable pressure of an oil pump that generates a source pressure in the hydraulic circuit in consideration of a change in the volume of the oil chamber due to movement of the movable sheave;
Windup amount setting means for setting a windup amount based on the dischargeable pressure estimated by the dischargeable pressure estimation means ,
The control device, wherein the control pressure setting means suppresses an integral action for setting the control pressure according to the deviation according to the windup amount set by the windup amount setting means .

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