JP2956418B2 - Transmission control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for a continuously variable transmission having a hydraulic servo mechanism for generating a shift control oil pressure in accordance with an operation amount of a shift actuator.

[0002]

2. Description of the Related Art Conventionally, as a shift control device of a continuously variable transmission, for example, a shift control device disclosed in Japanese Patent Application Laid-Open No. 2-292562 is known.

[0003] This conventional source discloses a V-belt type or toroidal type continuously variable transmission in which the speed ratio is steplessly controlled while receiving a reaction force of a transmission torque by a hydraulic pressure of a shift control hydraulic pressure from a hydraulic servo mechanism. In this case, the gear ratio fluctuates depending on the magnitude of the engine torque. Therefore, the gear ratio target value is corrected according to the magnitude of the engine torque, and the gear shift actuator is feedback-controlled in accordance with the deviation between the corrected target value and the actual value detected. An apparatus is disclosed.

[0004]

However, in the above-described conventional continuously variable transmission, all changes other than the characteristic change due to the engine torque among the feedforward characteristics of the target gear ratio and the actuator operation amount are controlled by feedback control. For example, when the target value changes abruptly during a step-down shift or the like, an overshoot in which the actual value protrudes from the target value in shift control may occur. Remains.

That is, the feedforward characteristic depends on the actuator operation amount and the transmission input torque, and the transmission input torque depends on the engine torque, the torque converter characteristic, and the transmission characteristic. When the characteristics of the throttle opening to the target engine rotation change due to a change or the like, the characteristics of the throttle opening to the transmission input torque change, and the feedforward characteristics change.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to control the shift control of a continuously variable transmission having a hydraulic servo mechanism for generating a shift control hydraulic pressure in accordance with the operation amount of a shift actuator. An object of the present invention is to improve convergence responsiveness of an actual value to a target value when the target value changes suddenly.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, a shift control device for a continuously variable transmission according to the present invention comprises a target value setting step.
Step, target gear ratio calculating means and actuator operation amount calculating means
Transmission input torque by at least one of the
A means for performing torque compensation based on the magnitude and performing shift control based on the actuated operation amount of the torque-compensated actuator.

That is, as shown in the claim correspondence diagram of FIG. 1, a shift actuator a operated by an external command, a hydraulic servo mechanism b for generating a shift control oil pressure in accordance with the operation amount of the shift actuator a, A continuously variable transmission c in which the gear ratio is controlled steplessly while receiving a reaction force of the transmission torque by the hydraulic pressure of the shift control hydraulic pressure from the hydraulic servo mechanism b, and an engine load detecting means d for detecting an engine load
A vehicle speed detecting means e for detecting a vehicle speed; a transmission input torque detecting means f for directly or indirectly detecting an input torque to the continuously variable transmission c; and a target value set at least by an engine load and a vehicle speed. Target value setting means g, target gear ratio calculating means h for calculating a target gear ratio based on the set target value, and a calculated target gear ratio, and feedforward characteristics of the target gear ratio and the actuator operation amount. Actuator operation amount calculating means i for calculating an actuator operation amount based on the target value setting means g and target gear ratio calculation
Means h and actuator operation amount calculation means i
Either of the means, depending on the magnitude of the input torque of the transmission,
And a shift control means j for executing a torque compensation and outputting a control command for obtaining a torque-compensated actuator operation amount to the shift actuator a. Note that the transmission input torque detection means includes a slot.
Turbine torque characteristics with respect to tor opening and turbine speed
Direct calculator for calculating turbine torque using maps
For the gear, the target speed ratio and actuator operation amount
Turbine torque information during the process of creating
The information may be used as indirect detection means.

[0009]

When the vehicle is running, the target value is set by the target value setting means g based on at least the engine load from the engine load detecting means d and the vehicle speed from the vehicle speed detecting means e, and is set by the target gear ratio calculating means h. The target gear ratio is calculated based on the target value, and the calculated target gear ratio, the target gear ratio and the actuator are calculated by the actuator operation amount calculating means i.
An actuator operation amount is calculated based on a feedforward characteristic with the eta operation amount . And set the target value
Means g, target gear ratio calculating means h, and actuator operation amount
Transmission input by at least one of the calculating means i
Torque compensation is performed based on the magnitude of the torque, and the shift control unit j outputs a control command to obtain the torque-compensated actuator operation amount to the shift actuator a.

A shift control oil pressure is generated by the hydraulic servo mechanism b in accordance with the operation amount of the shift actuator a.
In the continuously variable transmission c, the speed ratio is steplessly controlled while receiving the reaction force of the transmission torque by the hydraulic pressure of the shift control hydraulic pressure.

As described above, the magnitude of the transmission input torque
By calculating the more compensated actuator operation amount, when the feedforward characteristic changes due to a change in the transmission input torque, the change in the actuator operation amount due to the characteristic change becomes the shift control in which the change is predicted in advance.

Therefore, unlike the case where the change in the feedforward characteristic is absorbed by the feedback control after the fact, the shift control is such that the actual value accurately follows the sudden change in the target value even when the target value changes suddenly. Become.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) First, the configuration will be described.

FIGS. 2 and 3 are sectional views showing a half-toroidal type continuously variable transmission (corresponding to a continuously variable transmission c) to which the transmission control device according to the first embodiment of the present invention is applied.

2 and 3, 1 is an input shaft, 2 is a loading cam, 3 is a cam roller, 4 is an input disk, 5 is a power roller, 6 is an output disk, 7 is an output gear, 8, 9 are bearings, 10 and 11 are trunnions, 12 is a control valve, 13 is a stepping motor (corresponding to a shift actuator a), 14 is a sensor rod, 15 is a link,
Reference numeral 16 denotes a precess cam, 17 denotes a spool, 18 denotes a sleeve, 19 denotes a first cylinder, 20 denotes a second cylinder, 21 denotes a third cylinder, and 22 denotes a fourth cylinder.

The input torque from the input shaft 1 is transmitted to the loading cam 2 → cam roller 3 → input disk 4 → power roller 5 → output disk 6 → output gear 7.

The bearing 8 supports the thrust force of the power roller 5. Also, the bearing 9 has input / output disks 4, 6
To support the axial force.

The reaction force of the driving force acting on the trunnions 10, 11 is received by the hydraulic pressures of the four hydraulic cylinders 19, 20, 21.

When power is transmitted between the input / output disks 4, 6 and the power rollers 5, and the rotation axes of all the power rollers 5 and the rotation axes of the input / output disks 4, 6 have intersections. The force balance in the y-axis direction in FIG. 3 is expressed by the following equation.

2Ft = PH · S−PL · S where PH: hydraulic pressure of the first and third cylinders 19 and 21;
PL: hydraulic pressure of the second and fourth cylinders 20, 22, S: pressure receiving area of the cylinder. First and third cylinders 19 and 21
And the second and fourth cylinders 20 and 22 communicate with each other by piping. The hydraulic pressures PH and PL are controlled by the control valve 12. That is, the control valve 12 and each cylinder 19,
Reference numerals 20, 21, 22 and the like correspond to the hydraulic servo mechanism b.

FIG. 4 is a block diagram showing an electronic control system of the shift control device according to the first embodiment.

In FIG. 4, 13 is a stepping motor, 30 is a CVT control unit, 31 is a throttle opening sensor (corresponding to engine load detecting means d), 32 is a vehicle speed sensor (corresponding to vehicle speed detecting means e), and 33 is an engine. A rotation speed sensor, 34 is a turbine rotation speed sensor, 35 is a select position switch, and 36 is other sensors and switches.

This CVT control unit 13
An electronic control circuit mainly composed of a microcomputer calculates an actuator operation amount based on various control input information, and outputs a step pulse command to the stepping motor 13 to obtain the actuator operation amount.

The throttle opening sensor 31 detects a throttle opening TVO.

The vehicle speed sensor 32 detects a vehicle speed VSP.

The engine speed sensor 33 detects the engine speed Ne.

The turbine speed sensor 34 detects a turbine speed Nt (input shaft speed) of a torque converter provided between an engine output shaft (not shown) and the input shaft 1 of the continuously variable transmission.

The select position switch 35 detects a range position (for example, P range, R range, N range, D range, Ds range) selected by a select lever (not shown) based on a switch signal.

Next, the operation will be described.

[Shift operation] Shifting in the half toroidal type continuously variable transmission is performed by controlling the tilt angle of the power roller 5. The force for tilting the power roller 5 is obtained by utilizing the side slip generated by moving the center axis of the power roller 5 in the y-axis direction in FIG. As shown in FIG. 3, when the rotation axis of the power roller 5 intersects with the rotation axes of the input / output disks 4 and 6 to balance the power and transmit the power, the stepping motor 13 causes the control valve 12 to rotate. When the sleeve 18 is moved in the x-axis direction, PH,
The pressure of PL changes, the trunnions 10 and 11 move in the y-axis direction (opposite directions), and the contact points between the power roller 5 and the input / output disks 4 and 6 change. As a result, a tilting force is generated, and the trunnions 10 and 11 tilt in directions symmetric to each other.

A sensor rod 14 is attached to each of the trunnions 10 and 11, and a tip of the sensor rod 14 is provided with a tilt amount via a link 15 to move the spool 17 of the control valve 12 in the x-axis direction (opposite to the sleeve 18). Is mounted.

The precess cam 16 is the first sleeve 1
The pressure is changed by moving the spool 17 so as to correct the displacement of 8, and the tilting is stopped when the forces are balanced.

[Shift Control Operation] FIG. 5 is a flowchart showing the flow of the shift control processing operation performed by the CVT control unit 30, and each step will be described below.

In step 50, the throttle opening TVO,
The vehicle speed VSP, the engine speed Ne, and the turbine speed Nt are input.

In step 51, the target turbine speed T.Nt is calculated from the throttle opening TVO and the vehicle speed VSP indicating the vehicle operating state and the D range shift pattern f1 shown in FIG. 6 (corresponding to the target value setting means g). ).

In step 52, the target turbine speed T.Nt (= input shaft speed) calculated in step 51,
The target speed ratio T.RATIO is calculated by the following equation using the vehicle speed VSP (= output shaft rotation speed) and the coefficient K1.

T.RATIO = K1 * (T.Nt / VSP) In step 53, the throttle opening TVO and the turbine speed Nt and the turbine torque characteristic map f2 shown in FIG.
Calculates the turbine torque Tt (corresponding to the transmission input torque detecting means f).

In step 54, the feedforward operation amount FF is calculated based on the turbine torque Tt calculated in step 53, the target speed ratio T.RATIO calculated in step 52, and the speed ratio-operation amount map f3 shown in FIG. It is calculated (corresponding to the actuator operation amount calculating means i).

In step 55, a deviation e between the turbine speed Nt and the target turbine speed T.Nt is calculated.

In step 56, the stepping motor operation amount STEP is calculated by the sum of the feedforward operation amount FF and the feedback operation amount (Kp * e + ΣKi * e). Here, Kp is a proportional coefficient, and Ki is an integral coefficient.

In step 57, a step pulse command based on the stepping motor operation amount STEP in step 56 is sent to the stepping motor 13 (corresponding to the shift control means j).

Thus, the stepping motor operation amount ST
The motor shaft of the stepping motor 13 rotates by an angle corresponding to EP.

[Shift control] In the shift control of the first embodiment,
In step 53, the turbine torque characteristic map f shown in FIG.
2, a feedforward manipulated variable FF is calculated at step 54 based on a gear ratio-operated variable map f3 using the turbine torque Tt as a parameter shown in FIG. The deviation e between Nt and the target turbine speed T.Nt is calculated.
P is calculated by the sum of the feedforward manipulated variable FF and the feedback manipulated variable (Kp * e + ΣKi * e).

As described above, the feedforward operation amount FF is calculated based on the transmission ratio-operation amount map f3 using the turbine torque Tt (transmission input torque) as a parameter. When the characteristic changes, the change in the stepping motor operation amount STEP due to the characteristic change is the shift control predicted in advance.

Therefore, unlike the case where the change in the feedforward characteristic is absorbed by the feedback control after the fact, even when the target turbine speed T.Nt (target input speed) changes suddenly, the target turbine speed T. The shift control is such that the actual turbine speed Nt follows the sudden change of .Nt with high accuracy.

In particular, in the case of a toroidal type continuously variable transmission, it is necessary to remove the influence of the turbine torque Tt on the shift in advance, because the shift is performed while receiving the torque reaction force by the servo hydraulic pressure. This shows a phenomenon in which the servo hydraulic pressure fluctuates even when the transmission input torque fluctuates, and a shift occurs regardless of the shift control. In addition, the speed change range may reach up to about 30% of the total speed range, and the influence of the transmission input torque cannot be overlooked.

Next, the effects will be described.

(1) In a transmission control device of a half-toroidal type continuously variable transmission having a hydraulic servo mechanism for generating a transmission control hydraulic pressure PH, PL in accordance with the operation amount of the stepping motor 13, a turbine torque Tt which is an input torque of the transmission.
Is used as the parameter to calculate the feedforward operation amount FF based on the gear ratio-operation amount map f3 using the parameter as a parameter, and thus the speed is controlled. Therefore, when the target turbine speed T.Nt changes suddenly, the actual Of the turbine rotation speed Nt can be improved.

FIG. 9 shows the results of experiments conducted by the present inventors.

In this experiment, the downshift by depressing the accelerator is performed according to the flowchart of FIG. 5 (the present invention), and the transmission input speed (turbine speed) is set to the target value without considering the turbine torque Tt. (Conventional example).

According to this experiment, as shown in FIG. 9, in the conventional example, the input rotation overshoots the target input rotation, whereas in the present invention, the input rotation overshoots the target input rotation. The result was obtained without convergence.

(2) Since the continuously variable transmission to which the speed change control for calculating the feedforward manipulated variable FF corresponding to the turbine torque Tt is applied is a half-toroidal type continuously variable transmission having a large fluctuation effect of the turbine torque Tt, the speed change control is performed. In this case, the margin for improving the convergence responsiveness to the target value can be increased.

(3) In detecting the turbine torque Tt, the throttle opening TVO and the turbine speed Nt
And the turbine torque Tt is calculated using the turbine torque characteristic map f2 shown in FIG. 7, so that the turbine torque information can be easily obtained without using a torque sensor while being advantageous in cost.

(Second Embodiment) In the second embodiment, a shift pattern f1 indicating the relationship between the throttle opening TVO, the vehicle speed VSP and the target turbine speed T.Nt, and a target shift using the throttle opening TVO as a parameter. Transmission ratio-operation amount map f showing the relationship between ratio T.RATIO and feedforward operation amount FF
In this example, the turbine torque information is included in the gear ratio-operation amount map f2 in advance by using three characteristics based on the turbine torque Tt in setting the gear ratio-operation amount map f2. is there.

Since the system configuration is the same as that of the first embodiment, illustration and description are omitted.

Next, the operation will be described.

[Shift control operation] FIG. 10 is a flowchart showing the flow of the shift control processing operation performed by the CVT control unit 30, and each step will be described below.

In step 100, the throttle opening TV
O, vehicle speed VSP, engine speed Ne, turbine speed N
t is input.

In step 101, the target turbine rotational speed T.Nt is obtained based on the throttle opening TVO and the vehicle speed VSP indicating the vehicle operating state and the D range shift pattern f1 shown in FIG.
Is calculated (corresponding to the target value setting means g).

In step 102, the target turbine speed T.Nt calculated in step 51 (= input shaft speed)
The target speed ratio T.RATIO is calculated by the following equation using the vehicle speed VSP (= output shaft rotation speed) and the coefficient K1.

T.RATIO = K1 * (T.Nt / VSP) In step 103, the throttle opening TVO and the target speed ratio T.RATIO calculated in step 102 and the speed ratio-operation amount map f2 shown in FIG. As a result, the feedforward operation amount FF is calculated (corresponding to the transmission input torque detection means f and the actuator operation amount calculation means i).

Here, as shown in FIG. 11, the gear ratio-operating amount map f2 has a relationship of T.Nt to TVO, VSP.
According to the range shift pattern f1 and the first turbine torque characteristic map f (Tt1), which is the relationship between Tt to TVO and T.Nt, T
A second turbine torque characteristic map f (Tt2) having a relationship between t and TVO, VSP is created, and a speed ratio-operation, which is a relationship between the second turbine torque characteristic map f (Tt2) and a gear ratio ~ STEP, Tt, is further created. A speed ratio-operation amount map f2 using the throttle opening TVO as a parameter is set by the amount map f (Tt3). That is, the speed ratio-operation amount map f2 is a characteristic in which turbine torque information is used in the process of creating the speed ratio-operation amount map f2 and the turbine torque Tt is indirectly used as a parameter.

In step 104, the turbine speed Nt
And a deviation e between the target turbine speed T.Nt and the target turbine speed T.Nt are calculated.

In step 105, the stepping motor operation amount STEP is calculated by the sum of the feedforward operation amount FF and the feedback operation amount (Kp * e + ΣKi * e).

In step 106, a step pulse command based on the stepping motor operation amount STEP in step 105 is sent to the stepping motor 13 (corresponding to the shift control means j).

Thus, the stepping motor operation amount ST
The motor shaft of the stepping motor 13 rotates by an angle corresponding to EP.

Therefore, in the second embodiment, the following effects can be obtained in addition to the effects (1) and (2) of the first embodiment.

(4) As the gear ratio-operating amount map f2,
In the process of the creation, the turbine torque information is used, and a characteristic in which the turbine torque Tt is indirectly set as a parameter is used to perform the gear shift control. Shift control can be performed in consideration of a change in the feedforward characteristic.

Although the embodiment has been described with reference to the drawings, the specific configuration is not limited to the embodiment, and even if there are changes and additions without departing from the scope of the invention, the invention is included in the invention. It is.

For example, in the embodiment, an example in which the present invention is applied to a half-toroidal type continuously variable transmission is shown. However, the present invention can be applied to a V-belt type continuously variable transmission having a hydraulic servo mechanism.

In the embodiment, the example in which the target value is set to the target turbine speed is shown, but the target value may be set to the target engine speed.

In the embodiment, the example in which the throttle opening sensor is used as the engine load detecting means has been described. However, the engine load may be detected in consideration of the running load such as the throttle opening and the road surface gradient.

[0074]

In the present invention, as has been described above, according to the present invention, the shift control system for a continuously variable transmission having a hydraulic servo mechanism arranged to produce a shift control hydraulic pressure in response to the operation amount of the shift actuator, the target value setting means And target gear ratio calculation means
And / or actuator operation amount calculation means
By means of transmission input torque by means of
The execution, the actuator operation amount of torque compensated
Ri due to the means for performing transmission control, transmission input torque
Is obtained, the convergence responsiveness of the actual value to the target value can be improved when the target value changes abruptly due to the change in.

In particular, the present invention is useful in application to speed change control of a toroidal type continuously variable transmission.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims showing a shift control device for a continuously variable transmission according to the present invention.

FIG. 2 is a cross-sectional view showing a half toroidal type continuously variable transmission to which the transmission control device of the first embodiment is applied.

FIG. 3 is a sectional view taken along line AA of FIG. 2 showing a half toroidal type continuously variable transmission to which the transmission control device of the first embodiment is applied.

FIG. 4 is a block diagram illustrating an electronic control system of the shift control device according to the first embodiment.

FIG. 5 is a flowchart showing a flow of a shift control processing operation performed by a CVT control unit of the device of the first embodiment.

FIG. 6 is a characteristic diagram of a target turbine speed used for shift control in the continuously variable transmission according to the first embodiment.

FIG. 7 is a graph showing turbine torque characteristics used in the first embodiment.

FIG. 8 is a gear ratio-STEP map in the first embodiment.

FIG. 9 is a diagram illustrating a comparison experiment result between a target input rotation and an actual input rotation at the time of a depressed downshift in the apparatus of the first embodiment and the conventional apparatus.

FIG. 10 is a flowchart illustrating a flow of a shift control processing operation performed by the CVT control unit of the first embodiment.

FIG. 11 is a characteristic block diagram showing a process for obtaining a gear ratio-STEP map used in gear shift control in the second embodiment.

[Explanation of symbols]

 a speed change actuator b hydraulic servo mechanism c continuously variable transmission d engine load detecting means e vehicle speed detecting means f transmission input torque detecting means g target value setting means h target gear ratio calculating means i actuator operation amount calculating means j shift control means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16H 59:70 63:06

Claims (3)

(57) [Claims] 1. A shift actuator operated by an external command, a hydraulic servo mechanism for generating a shift control hydraulic pressure in accordance with an operation amount of the shift actuator, and transmission by a hydraulic pressure of the shift control hydraulic pressure from the hydraulic servo mechanism A continuously variable transmission in which the gear ratio is steplessly controlled while receiving a reaction force of torque; an engine load detecting means for detecting an engine load; a vehicle speed detecting means for detecting a vehicle speed; and an input to the continuously variable transmission. Transmission input torque detecting means for directly or indirectly detecting torque; target value setting means for setting a target value at least based on an engine load and a vehicle speed; and a target gear ratio calculating a target gear ratio based on the set target value. a ratio calculating means, a target speed ratio calculated actuator manipulated variable based on the feed forward characteristics of the target gear ratio and the actuator operation amount An actuator operation amount calculating means for calculating said target value setting means and the target speed ratio calculating means and the actuator
At least one of the data operation amount calculation means.
Executes torque compensation based on the speed input torque, and
And a shift control unit that outputs a control command for obtaining a torque- compensated actuator operation amount to the shift actuator, the shift control device for a continuously variable transmission. 2. A transmission control device for a continuously variable transmission according to claim 1.
In place The transmission input torque detecting means is provided with a throttle opening and a torque.
-Based on turbine torque characteristics map for bin speed
Direct calculation means for calculating turbine torque
A shift control device for a continuously variable transmission, characterized by: 3. A shift control device for a continuously variable transmission according to claim 1.
In place The transmission input torque detecting means is connected to a target gear ratio and an active gear.
Create feedforward characteristics with the MV
Indirect detection means using turbine torque information in the process
A shift control device for a continuously variable transmission, comprising: