JPH09229172A - Control device of continuously variable transmission for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a trouble that the actual value repeats a vibration around a target value, by controlling to give a small input when the difference between a target change gear ratio and the actual change gear ratio is small, and to give large input when the difference is large, in the device carrying out a feedback control based on the deviation of change gear ratio. SOLUTION: In a toroidal type continuously variable transmission 100, a target engine speed is calculated in a target gradient angle computing device 603, a target change gear ratio is calculated depending in the target engine speed, and a target gradient angle is calculated. And a specific function relation is output by a non-linear converter device 600. This function relation is a non- linear function in which the input and the output have the proportional relation in the outer side of a non-linear area 800, the inclination is made zero the origin inside the non-linear area 800, and the inclination is made 1 near the points A and -A. And a PI control computing device 606 makes the output from the non-linear converter device 600 to an input, adds a value multiplying a proportional gain to the deflection, and a value multiplying an integral gain to the integral value of the deviation, and outputs the resultant value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control method for a continuously variable transmission for a vehicle.

[0002]

2. Description of the Related Art Mounting a continuously variable transmission on an automobile makes it possible to use the output characteristics of an engine efficiently, and therefore, in comparison with the case where a stepped transmission is mounted, not only in power performance but also in fuel efficiency. Is known to have an advantage. Further, the continuously variable transmission also has an advantage that it is easy to perform a gear shift operation that does not cause a gear shift shock accompanying the gear shift operation, which is difficult to avoid with a stepped transmission. However, in order to exert the advantages of the continuously variable transmission, the gear ratio of the continuously variable transmission must be appropriately controlled to a desired gear ratio that achieves the power performance and the fuel efficiency performance. The present invention relates to the control of the gear ratio of the continuously variable transmission, but a toroidal type continuously variable transmission in which the effect of the present invention is particularly remarkable will be described below.

In a toroidal type continuously variable transmission known as Japanese Patent Laid-Open No. 58-54262, a power roller is arranged between coaxially arranged input / output disks, and the power roller is pressed against the input / output disk with a large force to input. A continuously variable transmission using a traction drive system that transmits power by shearing an oil film at a contact point between a disk and a power roller and a contact point between the power roller and an output disk. In the toroidal type continuously variable transmission, the rotational force is speed-changed and transmitted according to the ratio of the input disk radius at the contact point between the input disk and the power roller and the output disk radius at the contact point between the output disk and the power roller. At this time, axes that are perpendicular to the rotation axis of the input / output disk and the rotation axis of the power roller arranged coaxially are called the y-axis, and the displacement in the y-axis direction is called the y-displacement. Rotation around the y-axis, and this rotation is called tilting. By causing this tilting, the contact point between the input / output disk and the power roller is changed, whereby the input / output disk radius at the contact point. The gear ratio is changed by changing the ratio to realize a continuously variable transmission mechanism. Therefore, the gear ratio of the toroidal type continuously variable transmission is uniquely determined by the tilt angle of the power roller. Hereinafter, the tilt angle is synonymous with the gear ratio.

This tilting is performed by slightly displacing the power roller in y. That is, when the power roller undergoes y displacement, a tilting force that causes tilting is generated at the contact point between the input disk and the power roller and the contact point between the power roller and the output disk, which causes tilting. . Therefore, in a toroidal type continuously variable transmission, y
By having a mechanism that causes displacement, the tilt angle can be controlled to any tilt angle, and by feeding back the tilt angle to the mechanism that causes y displacement, a toroidal type continuously variable transmission can be used at any tilt angle. You can control the device.

Since this tilting force is caused by the force transmitted between the input / output disk and the power roller at the contact point between the power roller and the input / output disk,
The speed change speed of the toroidal type continuously variable transmission depends on the power roller rotation speed and the tilt angle.

The feedback mechanism as described above may be a mechanical link mechanism. Japanese Patent Laid-Open No. 58-54 discloses such a mechanical feedback control mechanism.
There is a mechanical feedback mechanism composed of a cam mechanism and a hydraulic mechanism as shown in Japanese Patent Laid-Open No. 262 and JP-A-3-288062. An example of such a configuration is shown in FIG. In the example shown in FIG. 17, when the actuator 532 drives the sleeve valve 533, a hydraulic path is opened between the spool valve 534 and the sleeve valve 533, and the hydraulic pressure generated here displaces the hydraulic cylinder mechanism 511 and the power roller 50
Give y displacement to 3. The y displacement of the power roller 503 causes tilting of the power roller 503 by the above mechanism, and this tilting is caused by the precess cam 530.
34 to the spool valve 534 and the sleeve valve 5 again.
The hydraulic path to and from 33 is closed, the y displacement of the power roller is restored, and the tilt interlocking is stopped. That is, feedback control is performed with the actuator position as the target value, so that the tilt angle of the power roller 503 is the actuator 532.
Given by the position of.

However, in such a configuration,
Since the displacement of the power roller y is very small, if the mechanical feedback mechanism is partially deformed by the torque transmitted by the toroidal type continuously variable transmission, there is a problem that a deviation from the target gear ratio occurs. In order to deal with such a problem, a target gear ratio calculated from a target rotational speed that can achieve good power performance and fuel efficiency performance calculated from conditions such as throttle opening or intake pipe negative pressure and vehicle speed. On the other hand, the applicant of the present invention has proposed an invention in which an electronic feedback control system for driving an actuator of a toroidal type continuously variable transmission so that actual gear ratios are matched is newly added in addition to a mechanical feed bank system. 7
It has been proposed in No. 71495.

That is, as shown in FIG. 15, the throttle opening 101 and the vehicle speed 102 are acquired by a sensor, the target gear ratio calculating device 103 calculates a target gear ratio from this, and the gear ratio detecting device 106 acquires the target gear ratio. A predetermined gain 201 is added to the difference from the transmission ratio of the toroidal type continuously variable transmission 100.
By performing a proportional feedback control in which a value obtained by multiplying by is given to the actuator of the toroidal type continuously variable transmission 100,
The gear ratio of the toroidal type continuously variable transmission matches a predetermined target gear ratio, and the engine speed is in a state where it matches the speed at which good power performance and fuel efficiency performance are obtained.
In the case where the toroidal type continuously variable transmission 100 has the mechanical feedback system, due to the peculiar problem that the transmission ratio causes a deviation in the gear ratio,
It requires a relatively large feedback gain.

[0009]

However, there is the problem of the resolution of the sensor and the actuator here. That is, it is general from the viewpoint of reliability and cost to use a method for calculating the rotation speed from the pulse time interval using a sensor that outputs a predetermined number of pulses for each rotation as the vehicle rotation speed measurement sensor. However, when measuring the time width of the pulse interval, there is a constraint of the minimum resolution of the measurement time. Also in the actuator, a step motor without a brush is more reliable than a DC motor having a contact point with a brush, but in a step motor, the operation is step-like, and the minimum resolution of actuation is There is a problem of being low.

When such a sensor and an actuator having a low resolution are used, in feedback control, the actual value does not match the target value as shown in FIG. 16, and the actual value repeats vibration around the target value. May cause phenomena. In particular, in the toroidal type continuously variable transmission in which the transmission ratio varies due to the transmission torque,
It is necessary to set the feedback gain to a large value, and vibration due to such small amount resolution tends to become more prominent. Such vibrations may be experienced, and may cause a driver to feel uncomfortable.
Further, when the step motor is used, it also causes a step-out phenomenon of the step motor, which significantly impairs the performance of the toroidal type continuously variable transmission.

[0011]

The present invention has been made to solve such a problem, and its essence is, as shown in FIG. 2, different from a linear gain proportional to a normal deviation, and a target value. And a small difference between the actual value and the actual value, a small gain,
When the difference between the target value and the actual value is large, a non-linear gain that gives a large gain is used to suppress the vibration phenomenon around the target value as shown in FIG. 16 even when the sensor and the actuator resolution are low. To do. Further, the present invention has an effect of reducing not only the resolution of the sensor and the actuator but also the case where vibration occurs near the target value due to noise or the like.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described. FIG. 3 shows the first embodiment of the present invention. The first embodiment is in accordance with the basic configuration of the present invention shown in FIG. 1. This basic configuration is non-linear with a gain multiplied by a difference between a target gear ratio and an actual gear ratio, as compared with the configuration of the conventional example of FIG. Gain 10
The present embodiment is characterized in that it is set to 4.
In order to improve the performance against disturbance, the PI control law is adopted, and in the toroidal type continuously variable transmission, the tilt angle, which is equivalent to the gear ratio, is controlled. The first embodiment is a toroidal type continuously variable transmission in which a tilt angle is controlled by a target tilt angle calculation device 603, a non-linear conversion device 600, a PI control calculation device 606, a tilt angle detection device 602, and a step motor 601. The device 100.

Toroidal type continuously variable transmission 10 in FIG.
0, the mechanical feedback mechanism has the structure shown in FIG. 4, and the structure will be described below. Transmission case 710
Among them, a pair of power rollers 723 (1) and 723 (2) are provided on the input disk 712 and the output disk (not shown because the surfaces are opposed to the input disk). These power rollers 723 are arranged on both sides of the input shaft 711 so as to be rotatable around common tilt axes 723a and 723b which are orthogonal to the center line of the input shaft 711.
3 (1) and 723 (2) are individually tilting shafts 724 (1),
724 (2). Tilt axis 724 (1),
724 (2) is the corresponding power roller 723 (1), 7
Tilting axis lines 723a, 7 orthogonal to the rotation axis line 23 (2)
Both ends are supported by radial bearings 725 and 726 so that they can rotate around 23b.
Radial bearing 72 above (1), 724 (2)
5 and the lower radial bearings 726 are connected by tie rods 727 and 728, respectively.

The centers of the tie rods 727 and 728 are connected to the transmission case 710 via joints 729 and 730, respectively, and the tilt shafts 724 (1) and 724 (2) are respectively tilted by hydraulic pistons 731 and 732. 723a, 7
It is possible to move up and down in the directions of 23b in opposite directions. For this reason, the hydraulic pistons 731 and 732 are not connected to the transmission case 710.
To the hydraulic chambers 733 (1), 733 (2), 734
(1) and 734 (2) are formed. One of the tilt axes 7
A rod 724a extending in the direction of the tilt axis is installed at the lower end of 24 (1), and a cam 735 is fixed to the tip thereof.

The hydraulic pump 740 supplies hydraulic oil to the shift control valve 7
41. The shift control valve 741 is provided in the hydraulic chamber 733.
(1), 733 (2), 734 (1), 734 (2). The shift control valve 741 is configured so that the sleeve 742 and the spool 7 are configured to be movable relative to each other.
43. The spool 743 is connected to the cam 735 and the link 736, and the power roller 723
According to the tilt angle and the vertical displacement of (1), the spool 7
43 position is decided. On the other hand, the sleeve 742 is moved by the actuator 707.

In this structure, the link 736 and the cam 73
5, hydraulic pump 740, shift control valve 741, spool 7
43, sleeve 742, hydraulic pistons 731, 732,
Hydraulic chambers 733 (1), 733 (2), 734 (1), 7
34 (2) constitutes a mechanical feed bank mechanism.

Next, the operation of the toroidal type continuously variable transmission 100 will be described. The power that reaches the input disk 712 from the input shaft 711 is transmitted to the output disk through the rotation of the power roller 723, and then is transmitted to the output shaft through the output shaft (not shown in FIG. 4). At this time, the input disk 71
2 and the radius of the input disc at the contact point of the power roller 723,
The ratio of the radius of the output disc and the radius of the output disc at the contact point of the power roller 723 is the gear ratio, and is uniquely determined by the tilt angle of the power roller 723 around the tilt shaft 724.

Next, the operation of the mechanical feedback mechanism will be described. When the toroidal continuously variable transmission 100 is fixed at a specific gear ratio, the relative positional relationship between the sleeve 742 and the spool 743 is in the reference state, and the forces acting on the hydraulic pistons 731 and 732 are in a balanced relationship. .

Next, when the operation of changing the gear ratio of the toroidal type continuously variable transmission 100 is performed, a command is given to the actuator 707 to move the spool 743 to a position corresponding to the target gear ratio. This correspondence is related to the cam 735 and the link 73.
6 determined by the mechanical feedback gain. When the spool 743 moves, the relative positional relationship with the sleeve 742 deviates from the reference state,
The oil passage opens there, and the hydraulic chambers 733 (1) and 733 (2) are opened.
And the hydraulic pressure acting on 734 (1) and 734 (2) changes, and the operating force is generated in the hydraulic pistons 731 and 732.
This force causes the tilting shaft 724 to be displaced in the vertical direction from the neutral position shown in FIG. 4, and the power roller 723 receives a tilting force from the input disc 712 and the output disc, and the tilting axes 723a and 723b. A tilting movement is started around. The tilt angle of the power roller 723 determines the contact position between the input disk 712 and the power roller 723 and between the power roller 723 and the output disk, and thus the gear ratio. The cam 735 is the power roller 7
When the tilt angle of 23 is converted into the movement of the sleeve 742 and the sleeve 742 and the spool 743 are in the relative positional relationship of closing the oil passage, the forces acting on the hydraulic pistons 731 and 732 return to the equilibrium relationship again. That is, spool 743
The power roller 7 of the toroidal type continuously variable transmission 100 is set by setting the position so as to balance with the desired tilt angle.
23 The tilt angle can be controlled, and the gear ratio is uniquely determined by the tilt angle.

Returning to FIG. 3, the operation will be described. The target tilt angle calculation device 603 includes a throttle opening 101,
A target engine speed that is appropriate for power performance and fuel efficiency performance is calculated from the vehicle speed 102, a target gear ratio is calculated from this, the vehicle speed, the final gear ratio, and the tire diameter, and the target tilt angle is calculated. The nonlinear conversion device 600 is
The difference between the target tilt angle and the tilt angle of the toroidal type continuously variable transmission 100 obtained by the tilt angle detection device 602 is input, and the functional relationship shown in FIG. 5 is output.

In FIG. 5, except the nonlinear region 800, the input and the output are in a proportional relationship. That is, in FIG. 5, if input> A, then output = (input-1A) + B, and the same relationship holds in the negative region. Further, in the non-linear region 800, the slope is 0 near the origin, and the slope is 1 near A and −A. PI control calculation device 606
Receives the output from the non-linear conversion device 600, adds the value obtained by multiplying the deviation by the proportional gain, and the value obtained by multiplying the integral value of the deviation by the integral gain, and outputs the result.

FIG. 7 shows the operation result of the control device in which the microcomputer is programmed using the first embodiment.
FIG. 6 shows the operation result of the conventional example. According to the result of the present invention shown in FIG. 7, unnecessary vibration of the step motor is reduced as compared with the conventional example shown in FIG.

FIG. 8 shows the second embodiment. When the non-linear gain is used as in the embodiment shown in FIG. 3, the following problems may occur. The case where the integral gain is 0 in the first embodiment shown in FIG. 3 will be described below. As shown in FIG. 9, if a deviation Δφ occurs, the step motor 601 is driven by θ1 steps in the proportional control using the normal linear gain, whereas the nonlinear function shown in FIG. 5 is used. Non-linear conversion device 60
In the case of 0, the step motor 601 is driven only by θ2 steps. Therefore, when the non-linear gain is used, when the disturbance occurs from the state where the deviation is small, the control system has a poor response.

In the case of the toroidal type continuously variable transmission 100,
As described above, a deviation due to the transmission torque may occur, and when the transmission torque changes rapidly, delay in deviation correction due to the use of the nonlinear gain may be a problem.

In the second embodiment, the throttle opening, which is one of the factors of the change in the transmission torque, is monitored, and the nonlinear conversion device 110 of FIG. 8 changes the nonlinear conversion function according to the throttle opening. , Addressing the above issues.
That is, as shown in FIG.
When the time change rate ΔTVO of ΔC is large, ΔC, which is a non-linear region, is made small, that is, the value of A is made small, and ΔT
The above problem is dealt with by changing it in a relation of A = α / (ΔTVO + γ) (Equation 1) (α and γ are predetermined constants) when VO is small.

The occurrence of vibration due to the actuator resolution is particularly problematic when the throttle opening is constant, the vehicle is traveling at a constant speed, and the target gear shift tilt angle is constant. Causes a deviation, that is, a large change in the throttle opening. Therefore, when the throttle opening is constant, that is, ΔTVO is small, the nonlinear effect is large, and when ΔTVO is large, the nonlinear effect is small. Of.

Further, as a third embodiment, as shown in FIG. 11, the same effect can be obtained by translating the nonlinear region in the direction opposite to the direction in which the deviation occurs.
That is, A1 = γ−βΔTVO (γ and β are predetermined constants) A2 = −γ−βΔTVO (Equation 2).

FIG. 12 shows the fourth embodiment. In the fourth embodiment, the throttle opening is used in the second embodiment of FIG. 8, but the switch 151 operated by the driver is used. In the fourth embodiment, the switch 151 is a soft shift mode switch that selects to output a target gear ratio that enables smooth shift operation. The non-linear conversion device 150 converts the non-linear function according to the value of the switch in the same manner as the non-linear conversion device 110 in FIG. 8 performs the conversion of the non-linear function shown in FIG. 10 or 11 with the time change rate ΔTVO of the throttle opening 101. I do. In the fourth embodiment, since the non-linear function is changed by the driver's operation, there is an inherent effect that the control characteristic of the toroidal type continuously variable transmission can be obtained according to the driver's intention.

FIG. 13 shows still another embodiment 5. In the fifth embodiment, the vehicle speed 102 is used while the throttle opening 101 is used in FIG. The toroidal type continuously variable transmission has a characteristic that the speed change speed varies depending on the rotation speed of the power roller because the speed change operation is performed by the rotational force of the power roller as described above. In the fifth embodiment, since the non-linear function changes from the vehicle speed signal, it is possible to always obtain a desired characteristic for the toroidal type continuously variable transmission whose characteristic changes depending on the power roller rotation speed, that is, the vehicle speed. Has the effect of.

FIG. 14 shows still another embodiment 6. While the throttle opening 101 is used in FIG. 8 in the sixth embodiment, the tilt angle detection device 60 is used.
The tilt angle signal from 2 is used. Since the toroidal type continuously variable transmission performs the gear shifting operation by the rotational force of the power roller as described above, it has a characteristic that the gear shifting speed varies depending on the contact point between the power roller and the input / output disk, that is, the tilt angle. is there. In the sixth embodiment, since the non-linear function changes from the vehicle speed signal, the characteristics of the toroidal type continuously variable transmission that changes depending on the tilt angle are as follows.
There is an inherent effect that the desired characteristics can always be obtained.

The embodiment of the present invention has been described in detail above with reference to the drawings. However, the specific configuration is not limited to this embodiment, and design changes and the like without departing from the gist of the present invention. Even if it is included in the present invention.

[0032]

As described above, in the control device for a continuously variable transmission according to claim 1 of the present invention, the difference between the target speed ratio and the actual speed ratio, or the target speed and the actual speed. In a continuously variable transmission for a vehicle that performs feedback control that gives the difference to the input, the difference between the target speed ratio and the actual speed ratio, or the difference between the target speed and the actual speed is smaller when the difference is smaller and larger when the difference is larger. Uses a non-linear relational function that gives a larger input, so even if the resolution of the sensor and actuator is low, it is possible to suppress the problem that the actual value repeatedly vibrates around the target value. The effect is obtained. According to the second aspect of the present invention, since the non-linear relational function is configured to change depending on the throttle opening, it is possible to cope with a rapid change in the transmission torque, and the non-linear relational function is used. , It is possible to secure a response when a disturbance occurs due to a small deviation. According to the third aspect of the invention, since the non-linear numerical relationship is changed by the switch operated by the vehicle driver, it is possible to obtain the control characteristic according to the intention of the driver. Claim 4
In the invention described above, since the non-linear functional relationship is configured to change depending on the vehicle speed, it is possible to always obtain a desired control characteristic for the toroidal-type continuously variable transmission whose characteristics change depending on the power roller rotation speed (vehicle speed). it can. According to the fifth aspect of the present invention, the non-linear functional relationship is configured to change according to the gear ratio or the physical quantity having a functional relationship with the gear ratio. Therefore, a desired control characteristic is always obtained for the toroidal continuously variable transmission. be able to.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a control device for a continuously variable transmission according to the present invention.

FIG. 2 is a diagram showing a nonlinear gain (functional relationship) of the present invention.

FIG. 3 is a diagram showing Embodiment 1 of the present invention.

FIG. 4 is a diagram showing a toroidal-type continuously variable transmission according to the first embodiment.

FIG. 5 is a diagram showing a conversion function according to the first embodiment.

FIG. 6 is a diagram showing an operation result of a conventional example.

FIG. 7 is a diagram showing an operation result of the first embodiment.

FIG. 8 is a diagram showing a second embodiment.

FIG. 9 is an explanatory diagram of the number of driving steps of a step motor.

FIG. 10 is an explanatory diagram of a nonlinear conversion number conversion method according to the second embodiment.

FIG. 11 is an explanatory diagram of a nonlinear conversion number conversion method according to the third embodiment.

FIG. 12 is a diagram showing a fourth embodiment.

FIG. 13 is a diagram showing a fifth embodiment.

FIG. 14 is a diagram showing a sixth embodiment.

FIG. 15 is a diagram showing a configuration of a conventional example.

FIG. 16 is a diagram showing the influence of the resolution of an actuator of a conventional example on control.

FIG. 17 is a diagram showing a conventional mechanical feedback mechanism.

[Explanation of symbols]

 100 Toroidal Type Continuously Variable Transmission Device 101 Throttle Opening 102 Vehicle Speed 103 Target Gear Ratio Calculation Device 104 Nonlinear Gain 105 Actuator 106 Gear Ratio Detection Device

Claims (5)

[Claims] 1. A continuously variable transmission for a vehicle, which performs feedback control to give a difference between a target speed ratio and an actual speed ratio or a difference between a target speed and an actual speed to an input, and a target speed ratio and an actual speed ratio. And a difference between the target rotation speed and the actual rotation speed are small, a smaller input is given, and a larger input is given when the difference is large, a control device for a continuously variable transmission for a vehicle. 2. The vehicle continuously variable transmission according to claim 1, wherein the difference between the target speed ratio and the actual speed ratio, or the difference between the target speed and the actual speed, and the continuously variable speed for the vehicle. A control device for a continuously variable transmission for a vehicle, wherein a non-linear functional relationship with an input given to the device changes depending on a throttle opening. 3. The vehicle continuously variable transmission according to claim 1, wherein the difference between the target speed ratio and the actual speed ratio, or the difference between the target speed and the actual speed, and the continuously variable speed change for the vehicle. A control device for a continuously variable transmission for a vehicle, wherein a non-linear functional relationship with an input given to the device is changed by a switch operated by a vehicle driver. 4. The vehicle continuously variable transmission according to claim 1, wherein the difference between the target speed ratio and the actual speed ratio, or the difference between the target speed and the actual speed, and the vehicle continuously variable speed. A control device for a continuously variable transmission for a vehicle, wherein a non-linear functional relationship with an input given to the device changes according to a vehicle speed. 5. The control device for a continuously variable transmission for a vehicle according to claim 1, wherein the difference between the target speed ratio and the actual speed ratio, or the physical quantity functionally related to the target speed ratio and the actual speed ratio and the functional relationship. A non-linear functional relationship between the difference between a certain physical quantity or the difference between the target rotation speed and the actual rotation speed and the input given to the continuously variable transmission for a vehicle changes depending on the gear ratio or the physical quantity having a functional relationship with this. A control device for a continuously variable transmission for a vehicle, comprising: