JPH074507A - Speed change controller for continuously variable transmission - Google Patents

Abstract

PURPOSE:To enhance the convergence response of the control by calculating the actuator operation quantity according to the feedforward characteristic between the goal speed change ratio for a hydraulic servo mechanism controlled by a speed change actuator and the actuator operation quantity. CONSTITUTION:During the vehicle travel, a goal value is set by a goal value setting means (g) in response to the engine load and vehicle speed detected by detection means (d),(e), and, according the goal value thus set, a goal speed change ratio is calculated by a goal speed change ratio calculation means (h).(Next, in an actuator operation-quantity calculation means (i), calculation is performed of the actuator operation quantity in accordance with the feed forward characteristic between the goal speed change ratio containing the transmission input torque and the actuator operation quantity, the calculated goal speed change ratio, and the transmission input torque detected by a detection means (f), whereupon to cause a control instruction to be outputted to a speed change actuator (a) through a speed-change control means (j). Thus, according to the pressure oil from a hydraulic servo mechanism (b) controlled by the speed change actuator (a), control is performed of the speed change ratio of a continuously variable transmission (c).

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 that produces a shift control hydraulic pressure according to an operation amount of a shift actuator.

[0002]

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

According to the conventional source, a V-belt type or toroidal type continuously variable transmission in which the gear ratio is controlled steplessly while receiving the reaction force of the transmission torque by the hydraulic pressure of the shift control hydraulic pressure from the 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 by the magnitude of the engine torque, and the gear change actuator is feedback-controlled according to the deviation between the corrected target value and the detected actual value. A device is disclosed.

[0004]

However, in the above-mentioned conventional continuously variable transmission, all the feedforward characteristics of the target gear ratio and the actuator operation amount other than the characteristic change due to the engine torque are controlled by the feedback control. Since the absorption is performed, there is a problem that, for example, when the target value changes abruptly at the time of stepping downshift or the like, overshoot in which the actual value protrudes from the target value may occur in the shift control. Remain.

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 shift characteristic. When the characteristics of the throttle opening to the target engine rotation change due to changes or the like, the characteristics of the throttle opening to the transmission input torque change and the feedforward characteristics change.

The present invention has been made in view of the above problems, and an object of the present invention is to control a shift of a continuously variable transmission having a hydraulic servo mechanism for generating a shift control oil pressure according to an operation amount of a shift actuator. In the apparatus, it is intended to improve the convergence response of the actual value with respect to the target value when the target value suddenly changes.

[0007]

In order to achieve the above-mentioned object, a shift control device for a continuously variable transmission according to the present invention is based on a feedforward characteristic of a target gear ratio including a transmission input torque as a parameter and an actuator operation amount. The actuator operation amount is calculated to perform gear shift control.

That is, as shown in the claim correspondence diagram of FIG. 1, a speed change actuator a operated by an external command, and a hydraulic servo mechanism b for generating a speed change control oil pressure according to the operation amount of the speed change actuator a. A continuously variable transmission c in which a gear ratio is controlled steplessly while receiving a reaction force of a transmission torque by hydraulic pressure of shift control hydraulic pressure from the hydraulic servo mechanism b, and an engine load detection means d for detecting an engine load.
A vehicle speed detecting means e for detecting the vehicle speed, a transmission input torque detecting means f for directly or indirectly detecting the input torque to the continuously variable transmission c, and a target value is set at least by the engine load and the vehicle speed. The target value setting means g, the target gear ratio calculating means h for calculating the target gear ratio based on the set target value, and the feedforward characteristics of the target gear ratio and the actuator operation amount including the transmission input torque as a parameter. An actuator operation amount calculation means i for calculating the actuator operation amount based on the actuator operation amount, and a shift control means j for outputting a control command for obtaining the actuator operation amount to the shift actuator a are characterized by being provided.

[0009]

When the vehicle is traveling, the target value setting means g sets a target value 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 the target gear ratio calculating means h sets the target value. The target gear ratio is calculated based on the target value, and the actuator operation amount calculation means i calculates the feedforward characteristics of the target gear ratio and the actuator operation amount including the transmission input torque as a parameter, and the calculated target gear ratio and transmission. Input torque detection means f
The actuator operation amount is calculated on the basis of the transmission input torque from, and the shift control means j outputs a control command for obtaining the calculated actuator operation amount to the shift actuator a.

A shift control hydraulic 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 gear ratio is controlled steplessly while receiving the reaction force of the transmission torque by the hydraulic pressure of the shift control hydraulic pressure.

As described above, the actuator operation amount is calculated based on the feedforward characteristic of the target gear ratio including the transmission input torque as a parameter and the actuator operation amount, so that the feedforward characteristic varies due to the variation of the transmission input torque. Is changed, the change in the actuator operation amount due to the change in the characteristic is the shift control predicted in advance.

Therefore, unlike the case where the feedback control absorbs a change in the feedforward characteristic afterwards, a shift control in which the actual value accurately follows the sudden change in the target value even when the target value suddenly changes. Become.

[0013]

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

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

2 and 3 are sectional views showing a half toroidal type continuously variable transmission (corresponding to the continuously variable transmission c) to which the shift control device of 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 disc, 5 is a power roller, 6 is an output disc, 7 is an output gear, 8 and 9 are bearings, 10 and 11 are trunnions, 12 is a control valve, 13 is a stepping motor (corresponding to the speed change actuator a), 14 is a sensor rod, 15 is a link,
Reference numeral 16 is a recess cam, 17 is a spool, 18 is a sleeve, 19 is a first cylinder, 20 is a second cylinder, 21 is a third cylinder, and 22 is a fourth cylinder.

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

The bearing 8 supports the thrust force of the power roller 5. Further, the bearing 9 is the input / output disk 4, 6
It supports the axial force of.

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

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

2Ft = PH.multidot.S-PL.multidot.S where PH is the hydraulic pressure of the first and third cylinders 19 and 21,
PL: hydraulic pressure of the second and fourth cylinders 20 and 22, S: pressure receiving area of the cylinders. First and third cylinders 19, 21
The second and fourth cylinders 20 and 22 communicate with each other through piping. The hydraulic pressures PH and PL are controlled by the control valve 12. That is, the control valve 12, each cylinder 19,
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 of 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 another sensor switch.

This CVT control unit 13 is
An electronic control circuit centered on 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 this actuator operation amount.

The throttle opening sensor 31 detects the throttle opening TVO.

The vehicle speed sensor 32 detects the vehicle speed VSP.

The engine speed sensor 33 detects the engine speed Ne.

The turbine rotation speed sensor 34 detects the turbine rotation speed Nt (input shaft rotation speed) of the torque converter provided between the 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) from a switch signal.

Next, the operation will be described.

[Shifting 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 can be obtained by utilizing the side slip generated by moving the central axis of the power roller 5 in the y-axis direction in FIG. Now, as shown in FIG. 3, when the rotation axis of the power roller 5 and the rotation axes of the input / output disks 4 and 6 intersect, the forces are balanced and the power is transmitted. When the sleeve 18 of 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 to each other), 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 mutually symmetrical directions.

A sensor rod 14 is attached to each of the trunnions 10 and 11, and a tip end of the sensor rod 14 is moved through a link 15 in a direction of the spool 17 of the control valve 12 in the x-axis direction (opposite to the sleeve 18). The precess cam 16 that changes to is attached.

This precess cam 16 is the first sleeve 1
The spool 17 is moved so as to correct the displacement of No. 8, the pressure is changed, 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 vehicle speed VSP indicating the vehicle operating condition 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 rotation speed T.Nt (= input shaft rotation speed) calculated in step 51,
The target speed ratio T.RATIO is calculated from the vehicle speed VSP (= output shaft speed) and the coefficient K1 by the following equation.

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

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

In step 55, the 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).

As a result, 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, the turbine torque Tt is calculated, the feedforward operation amount FF is calculated based on the gear ratio-operation amount map f3 with the turbine torque Tt shown in FIG. 8 as a parameter in step 54, and the turbine rotation speed is calculated in step 55. The deviation e between Nt and the target turbine speed T.Nt is calculated, and in step 56, the stepping motor operation amount STE is calculated.
P is calculated by the sum of the feedforward operation amount FF and the feedback operation amount (Kp * e + ΣKi * e).

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

Therefore, unlike the case where the feedback control absorbs the change in the feedforward characteristic afterwards, the target turbine speed T is also changed when the target turbine speed T.Nt (target input speed) suddenly changes. The shift control is such that the actual turbine speed Nt accurately follows a sudden change in .Nt.

In particular, in the case of a toroidal type continuously variable transmission, it is necessary to eliminate the influence of the turbine torque Tt on the gear shift in advance, because the gear shift is a system which receives the torque reaction force by the servo hydraulic pressure. The phenomenon that the servo oil pressure fluctuates even when the transmission input torque fluctuates, and a gear shift occurs regardless of the gear shift control. Moreover, this shift variation range may reach up to about 30% of the entire shift range, and the influence of this transmission input torque cannot be overlooked.

Next, the effect will be described.

(1) In a shift control device of a half toroidal type continuously variable transmission having a hydraulic servo mechanism for generating shift control hydraulic pressures PH and PL in accordance with an operation amount of the stepping motor 13, a turbine torque Tt which is a transmission input torque.
Since the device for performing the shift control by calculating the feedforward manipulated variable FF on the basis of the gear ratio-manipulated variable map f3 with the parameter as a parameter, the target turbine rotational speed T.Nt is actually changed when the target turbine rotational speed T.Nt suddenly changes. It is possible to improve the convergence response of the turbine rotation speed Nt.

Incidentally, the result of the experiment conducted by the present inventor is shown in FIG.

In this experiment, downshifting by depressing the accelerator is carried out according to the flowchart of FIG. 5 (the present invention), and the transmission input speed (turbine speed) is set to a target value without considering the turbine torque Tt. It was performed only by the feedback control (conventional example).

According to this experiment, as shown in FIG. 9, the input rotation overshoots the target input rotation in the conventional example, whereas the input rotation overshoots the target input rotation in the present invention. The result was that it converged without any problem.

(2) Since the continuously variable transmission to which the shift 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 influence of fluctuation of the turbine torque Tt, the shift control is performed. It is possible to take a large margin for improving the convergence response with respect to the target value in.

(3) When detecting the turbine torque Tt, the throttle opening TVO and the turbine speed Nt
Since the turbine torque Tt is calculated based on the turbine torque characteristic map f2 shown in FIG. 7, it is possible to easily obtain the turbine torque information while being advantageous in cost without using the torque sensor.

(Second Embodiment) In the second embodiment, a shift pattern f1 showing the relationship among 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. Gear ratio-operation amount map f showing the relationship between the ratio T.RATIO and the feedforward operation amount FF
2 is an example in which the turbine torque information is included in advance in the gear ratio-operation amount map f2 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, its illustration and description will be 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 determined by the throttle opening TVO and the vehicle speed VSP indicating the vehicle operating condition and the D range shift pattern f1 shown in FIG.
Is calculated (corresponding to the target value setting means g).

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

T.RATIO = K1 * (T.Nt / VSP) In step 103, the throttle opening TVO and the target gear ratio T.RATIO calculated in step 102, and the gear ratio-operation amount map f2 shown in FIG. Thus, 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, the gear ratio-manipulation amount map f2 is, as shown in FIG. 11, D, which is the relationship of T.Nt to TVO and VSP.
From 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), which is a relationship between t and TVO, VSP, is created. Further, a gear ratio-operation that is a relationship between the second turbine torque characteristic map f (Tt2) and a gear ratio: STEP, Tt. The gear ratio-operation amount map f2 with the throttle opening TVO as a parameter is set by the amount map f (Tt3). That is, the gear ratio-manipulation amount map f2 is a characteristic in which turbine torque information is used in the process of its creation and the turbine torque Tt is indirectly used as a parameter.

In step 104, the turbine speed Nt
The deviation e between the target turbine speed T.Nt and the target turbine speed T.Nt is 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).

As a result, 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 a gear ratio-operation amount map f2,
In the process of its creation, the turbine torque information is used, and the characteristic in which the turbine torque Tt is indirectly used as a parameter is set, so that the gear shift control is performed. The shift control can be performed in consideration of the change in the feedforward characteristic.

Although the embodiments have been described above with reference to the drawings, the specific structure is not limited to the embodiments, and modifications and additions within the scope not departing from the gist of the present invention are included in the present invention. Be done.

For example, in the embodiment, the example of application to the half toroidal type continuously variable transmission is shown, but it can also be applied to the V-belt type continuously variable transmission having a hydraulic servo mechanism.

In the embodiment, the target value is set to the target turbine speed, but it 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, but the engine load may be detected in consideration of the traveling load such as the throttle opening and the road surface gradient.

[0074]

As described above, according to the present invention, in the shift control device of the continuously variable transmission having the hydraulic servo mechanism for generating the shift control hydraulic pressure according to the operation amount of the shift actuator, the transmission input torque is increased. Since the means for performing gear shift control by calculating the actuator manipulated variable based on the feedforward characteristics of the target gear ratio and the actuator manipulated variable that include in the parameter, improves the convergence response of the actual value to the target value when the target value changes suddenly. The effect that can be achieved is obtained.

Particularly, it is useful in the application to the shift control of the toroidal type continuously variable transmission.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram 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 shift control device of the first embodiment is applied.

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

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

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

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

FIG. 7 is a turbine torque characteristic diagram used in the first embodiment device.

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

FIG. 9 is a diagram showing the results of comparative experiments between the target input rotation and the actual input rotation at the time of stepping downshift in the apparatus of the first embodiment and the conventional apparatus.

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

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

[Explanation of symbols]

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

Claims (1)

[Claims] 1. A shift actuator operated by a command from the outside, a hydraulic servo mechanism for generating shift control hydraulic pressure according to an operation amount of the shift actuator, and transmission by hydraulic pressure of the shift control hydraulic pressure from the hydraulic servo mechanism. A continuously variable transmission in which a gear ratio is controlled steplessly while receiving a reaction force of torque, an engine load detection means for detecting an engine load, a vehicle speed detection means for detecting a vehicle speed, and an input to the continuously variable transmission. Transmission input torque detection means for directly or indirectly detecting torque, target value setting means for setting a target value based on at least engine load and vehicle speed, and target speed change for calculating a target gear ratio based on the set target value The ratio calculation means and the actuator based on the feedforward characteristics of the target gear ratio including the transmission input torque as a parameter and the actuator operation amount. A shift control device for a continuously variable transmission, comprising: an actuator operation amount calculating means for calculating an actuator operation amount; and a shift control means for outputting a control command for obtaining the actuator operation amount to the shift actuator. .