JPH11141666A - Shift control device for continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress drop of the followup performance due to increase in the integral value in a continuously variable transmission equipped with a mechanical feedback system. SOLUTION: The arrangement according to the invention comprises a continuously variable transmission 10 which is equipped with a shift mechanism driven by a step motor 4 and a mechanical feedback system and changes the gear ratio continuously, and an integrator 74 means which calculates the target gear ratio in accordance with the operating condition and determines the integral of the deviation of the actual gear ratio from its target value. Further the arrangement includes a feedback control part to calculate the command value so that the actual gear ratio becomes identical to its target value and a step conversion part 75 to make restriction so that the drive amount of the step motor 4 does not exceed the specified range of driving. Thereby the integral operation is interrupted for the period in which the drive amount of the step motor 4 lies at the specified upper limit or lower limit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a shift control device for a continuously variable transmission.

[0002]

2. Description of the Related Art Continuously variable transmissions used in vehicles include:
Conventionally, continuously variable transmissions such as a V-belt type and a toroidal type have been known.
2. Description of the Related Art A toroidal-type continuously variable transmission as disclosed in JP-A-288062 is known.

As shown in FIGS. 7 and 8, a pair of input / output cone disks 1 and 2 arranged coaxially and a pair of power input / output disks that transfer power by frictional engagement between the input / output cone disks 1 and 2 are used. A so-called single-cavity toroidal transmission unit composed of power rollers 3 and 3,
The shift control device includes an electronic feedback system based on PI control in addition to a mechanical feedback system.

In this toroidal type continuously variable transmission 10, the power rollers 3, 3 are held and pressed between the input and output cone disks 1, 2, and the power roller 3 is an oil film between the input and output cone disks 1, 2. , The power is transmitted between the input and output cone disks 1 and 2.

The rotation of the input cone disk 1 is transmitted to the power roller 3 by the shearing force of the oil film, and the rotation of the power roller 3 is transmitted to the output cone disk 2 by the shearing of the oil film. The power transmission from 2 to the input cone disk 1 is similarly performed via the power roller 3.

[0006] The shearing force of the oil film is a speed difference generated between the input and output cone disks 1 and 2 and the power roller 3 and the pressure acting on the oil film, that is, the input and output cone disks 1 and 2
This is caused by the pressure pressing the power roller 3 between the two.

Therefore, if the pressing pressure is strong,
A torque can be transmitted with a small speed difference, and if the pressing pressure is small, a large speed difference is required.

Further, since the transmission of torque is due to the shearing force of the oil film, if a speed difference exceeding a predetermined value occurs, the oil film does not generate a shearing force, and the input / output cone disk 1,
Since the engagement relationship between the power roller 2 and the power roller 3 is broken,
Although it is desirable to apply a large pressing force, applying an unnecessary pressing force impairs the efficiency of power transmission. Therefore, it is necessary to set the pressing force according to the transmission torque.

For this reason, as shown in FIG. 8, the mechanism for applying the pressing force is provided between the cam disk 22 provided on the input shaft 20 connected to the engine side and the rear surface of the input cone disk 1. A loading cam 28 having a rotating shaft in the radial direction of the cam disk 22 is provided, and the input cone disk 1 provided with a predetermined inclined surface on the back surface is rotatably supported by the input shaft 20 with the input shaft 20.
The cam disk 22 and the input cone disk 1 have a predetermined inclined surface, and when a rotational phase difference occurs between the cam disk 22 and the input cone disk 1, the inclined surface formed on the rear surface of the input cone disk 1 and the cam disk As the loading cam 28 rolls between the slopes 22, the input cone disk 1 is pressed in the axial direction (O ₂ axis direction) of the input shaft 20, and is axially supported together with the output gear 29 via the bearing 30. The power roller 3 is pressed against the output cone disk 2 to generate a pressing force according to the transmission torque applied to the input shaft 20. The input shaft 20 is supported by the casing 19 via a bearing 31, and the output gear 29 is connected to driving wheels via an output shaft (not shown).

On the other hand, when the transmission torque of the continuously variable transmission 10 is small, the loading cam 28 does not operate. Therefore, a coned disk spring 21 for urging the input shaft 20 in the axial direction is provided on the bearing 31 side, and a predetermined spring is always provided. However, the urging force generated by the disc spring 21 cannot be remarkably increased in order to improve the transmission efficiency and to secure the assembling property.

The gear ratio of the toroidal type continuously variable transmission 10 is determined according to the radius at which the power roller 3 contacts the input cone disk 1 and the output cone disk 2, and
This change in gear ratio is performed by driving the O ₃ axial and displaceable trunnions 41, 41 around the axis in FIG. 7 as well as the axial supporting the power rollers 3,3, the power rollers 3 are trunnion 41 By the tilting motion that rotates around the axis of the trunnion 41 in accordance with the axial displacement of
The contact radius between the input and output cone disks 1 and 2 is continuously changed. The trunnion 41 supports the power roller 3 via the eccentric shaft 9.

Here, the shift control device will be described. As shown in FIG. 8, a hydraulic cylinder 6 having a piston 6a at the lower end of a trunnion 41 which responds to the hydraulic pressure supplied to the upper and lower oil chambers 6H and 6L. And these oil chambers 6H, 6
A shift control valve 5 for supplying oil pressure to the L
A step motor 4 that drives the sleeve 5b of the shift control valve 5 in response to a command from, and displacement around the axis shift control valve (vertical direction in FIG. 8) O ₃ axial trunnion 41 5
A mechanical feedback system is mainly composed of the precess cam 7 and the link cam 8 that feed back to the spool 5a.

The step motor 4 is rotated by receiving a shift command value (the number of steps) corresponding to the target speed ratio from the controller, and rotates the sleeve 5b of the shift control valve 5 and the spool 5a by the rack and pinion. It is driven via a mechanism and displaced from a predetermined neutral position relative to the spool 5a.

The transmission control valve 5 has an input port 5d connected to a hydraulic source 60, one communication port 5e connected to the oil chamber 6L of the hydraulic cylinders 6, 6, and the other communication port 5f connected to the hydraulic cylinders 6,6. To the oil chambers 6H. Then, while the spool 5a is connected to the precess cam 7 via the link cam 8, a sleeve 5b slidable in the axial direction between the outer periphery of the spool 5a and the inner periphery of the valve body 5c is provided.
It is driven by a step motor 4 via a rack and pinion.

Spool 5 driven by step motor 4
a, the two power rollers 3, 3
is displaced to O ₃ axially in response to hydraulic pressure applied to a, this time, the hydraulic pressure to each piston 6a, the power rollers 3, 3 facing is supplied to displace mutually opposite directions, for example, the left side in FIG. Is raised, the power roller 3 on the right side in the figure is lowered.

The power rollers 3 facing each other are
From the neutral position as shown intersecting the rotation axis O ₂ of the rotation axis O ₁ is output cone discs 1 and 2 are synchronously offset in accordance with the reverse displacement to each other of the trunnion 41.

[0017] Both power rollers 3,3 on the basis of the offset amount of the O ₃ axial input and output cone discs 1 and 2
Performs a tilting motion that rotates around a swing axis O ₃ (= rotation axis of the trunnion 41) orthogonal to its own rotation axis O _{1 by} the component force from the power roller for the input / output cone disks 1 and 2. By continuously changing the friction contact radii of the third and the third, the continuously variable transmission can be performed.

[0018] When the shift command value from the controller by such a continuously variable transmission is achieved, the O ₃ axial offset and the tilt angle of the power roller 3, the trunnion 4
1, feedback to the spool 5a of the shift control valve 5 via the precess cam 7 and the link cam 8,
Is returned to the initial neutral position relatively to the sleeve 5b, and the suction and discharge of the hydraulic oil to and from the oil chambers 6H and 6L are shut off.
Trunnion 41, 41 rotation axis O ₁ of the two power rollers 3,3, by returning to the neutral position that intersects the rotation axis O ₂ of the input and output cone discs 1 and 2, to maintain the achieved state of the shift command value It is.

The trunnion constituting in such a continuously variable transmission 10, because although O ₃ axial displacement of the trunnion 41 and the power roller 3 is very small (e.g., several mm), the torque transmitted, a feedback mechanism 4
If a part of 1 is deformed, there is a problem that an error occurs with respect to the target gear ratio.

[0020] That is, if the torque toroidal type continuously variable transmission is transmitted rapidly increases, the power roller 3 is subjected to O ₃ axial force at the contact point between the input and output cone discs 1 and 2, this piston When the trunnion 41 subjected to stress undergoes elastic deformation, it cannot support the power roller 3 and moves in the O ₃ axis direction, but the power roller 3 moves in the O ₃ axis direction. A tilting motion occurs according to the amount, and the actual gear ratio changes with respect to the target gear ratio.

Further, a feedback mechanism using the precess cam 7 and the link cam 8 works to control the transmission to a predetermined target gear ratio.
Is deformed, the distance between the rotation center (axis O ₁ ) of the power roller 3 and the precess cam 7 changes, so that the gear ratio constantly shifts by this difference.

Such a shift in the speed ratio is called a so-called torque shift. To eliminate the torque shift, an electronic feedback system based on the deviation between the target speed ratio and the actual speed ratio is added. The applicant of the present application
-296722.

In addition, the applicant of the present invention performs feedforward control in anticipation of delay of proportional integral control (hereinafter referred to as PI control) and deformation of a mechanical feedback system.
Japanese Patent Application Laid-Open Publication No. H8-108
No. 326887.

[0024]

As shown in FIG. 10, the amount of displacement of the sleeve 5b of the transmission control valve 5 is mechanically an upper limit value and a lower limit value (Lo and Hi side displacement limit positions). Therefore, it is necessary to limit the driving range of the step motor 4.

Assuming that the limitation of the drive range of the step motor 4 is a step motor drive limit amount, the limit amount takes into account mechanical errors such as dimensional tolerances and step-out of the step motor 4, as shown in FIG. In addition, it is desirable to set the displacement amount of the sleeve 5b smaller than the upper limit value and the lower limit value.

However, since the above-described restrictions are provided, in the above-mentioned Japanese Patent Application Laid-Open No. 8-326687, the PI
By the control, a command value is issued to the step motor 4 so that the target speed ratio and the actual speed ratio match, and when the command value reaches the step motor drive limit amount, the drive of the step motor 4 is stopped. However, at this time, if there is a deviation between the target gear ratio and the actual gear ratio, the integral value by the integral control is accumulated, and when the step motor 4 is driven in the reverse direction, the command value is calculated by the accumulated integral value. There is a problem that the start of the change of the transmission is delayed, and the followability of the shift control is reduced. For example, as shown in FIG. 9, when the step motor command value reaches the lower limit value and is not driven, the integral value by the PI control reaches the integral upper limit value. By the time the value starts to change, a delay occurs, and the followability is reduced.

This phenomenon is caused by the fact that the integration value is not stopped when the mechanically specific shift limit (upper limit or lower limit) of the continuously variable transmission is reached, as pointed out in JP-A-3-249463. Similar to a phenomenon in which the followability is deteriorated due to an abnormal value. However, in this Japanese Patent Application Laid-Open No. 3-249463, since the continuously variable transmission that directly controls the opening amount of the hydraulic valve by PI is controlled, the integral value Abnormal accumulation only takes place after the mechanically specific transmission ratio limit of the continuously variable transmission is reached.

On the other hand, Japanese Unexamined Patent Application Publication No.
In a conventional example such as that disclosed in Japanese Patent Application Publication No. 7-1995, a stepping motor 4 as an actuator is driven to displace a sleeve 5b of a transmission control valve 5, thereby changing a valve opening amount to start a change in a gear ratio. The spool 5a, which is relatively displaced in accordance with the change in the ratio, closes the sleeve 5b to maintain a speed ratio corresponding to the drive amount of the step motor 4.
A so-called tracking control type mechanical feedback system is provided. Therefore, before the speed ratio of the continuously variable transmission reaches the inherent speed ratio limit, the step motor drive limit amount based on the displacement limit position of the sleeve 5b is reached,
In spite of the fact that the value of the actual speed ratio has a margin with respect to the inherent speed ratio limit, there is a problem that the integral value is accumulated due to the stop of the driving of the step motor, and the followability is reduced as described above. .

Further, as shown in FIG. 10, when the stepping motor 4 loses synchronism and the original drive limit moves as indicated by the broken line in the figure, the speed ratio limit inherent to the continuously variable transmission is reduced. Even if there is a margin, there is a problem that the step motor drive limit is reached and the follow-up performance is reduced due to accumulation of the integral value as described above.

Accordingly, the present invention has been made in view of the above problems, and has as its object to suppress a decrease in followability due to an increase in an integral value.

[0031]

According to a first aspect of the present invention, there is provided a continuously variable transmission in which a speed change ratio is continuously changed by a transmission mechanism driven by an actuator, and a target shift of the continuously variable transmission in accordance with an operation state. Feedback control means for calculating the ratio and integrating the deviation between the actual speed ratio and the target speed ratio, and driving the actuator so that the actual speed ratio matches the target speed ratio; and A drive control device for controlling the drive amount of the continuously variable transmission so as not to exceed a predetermined drive range, wherein the drive amount of the actuator is set to an upper limit value or a lower limit value of a predetermined drive range. During a certain period, there is provided integration operation stopping means for stopping the integration operation of the integration means.

According to a second aspect of the present invention, there is provided a continuously variable transmission in which a speed change ratio is continuously changed by a speed change mechanism driven by an actuator, and a target speed ratio of the continuously variable transmission is calculated in accordance with an operation state. Feedback control means for driving the actuator so that the actual gear ratio matches the target gear ratio; and A shift control device for a toroidal-type continuously variable transmission, comprising: a drive amount regulating unit that regulates a drive amount of an actuator so as not to exceed a predetermined displacement range. And integrating operation stopping means for stopping the integrating operation of the integrating means while the amount is at a predetermined upper limit value or lower limit value.

[0033]

Therefore, according to the first invention, when electronic feedback control including integral control is performed, the drive amount of the actuator is regulated within a predetermined drive range.
A shift mechanism driven by the actuator, for example, can prevent deformation of the shift control valve, and further, when the drive amount of the actuator is at the upper limit or lower limit of these drive ranges, the integration operation of the feedback means is performed. Since the stop is temporarily performed, it is possible to suppress a decrease in follow-up performance due to an increase in the integral value as in the conventional example, to further improve the control accuracy of the shift control, and to use a step motor as the actuator. In the case of adoption, displacement of the transmission mechanism with respect to the control amount due to step-out, for example,
Even if the relationship with the valve opening is deviated and the valve position continues to be set to the upper limit or the lower limit, the integration operation is stopped during this time, so that the integral value is prevented from excessively increasing and the followability is prevented from deteriorating. Can be.

Further, the second invention detects a displacement amount of a transmission mechanism driven by an actuator, for example, a stroke of a transmission control valve, and as long as the displacement amount is at a predetermined upper limit value or lower limit value, Since the drive of the actuator and the integration operation are stopped, a speed change mechanism driven by the actuator, for example, to prevent deformation of the shift control valve, and to temporarily stop the integration operation of the feedback means, the conventional example As described above, it is possible to suppress a decrease in followability due to an increase in the integral value, and when a step motor is used as the actuator, the drive is performed based on the displacement amount of the transmission mechanism even if step-out occurs, so that the drive is performed. It is possible to further improve the stability of the shift control by preventing the shift of the range.

[0035]

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

FIG. 1 shows an example in which the present invention is applied to a shift control controller 52 of the continuously variable transmission 10 while adopting a single-cavity type toroidal type similar to the above-described conventional example as the continuously variable transmission 10.

The continuously variable transmission 10 is connected to the engine 11 via a torque converter 12 having a lock-up mechanism L / U on the input shaft 20 side, while the output shaft side (output cone disk 2 side) is shown. Not connected to the drive wheel,
The transmission mechanism and the mechanical feedback mechanism of the toroidal type continuously variable transmission 10 are shown in FIGS.
The shift is performed by the step motor 4 (actuator) driving the shift control valve 5 in response to a command from the shift control controller 52, and the same figure as that of the conventional example is used. And a duplicate description is omitted.

The shift control controller 52 is mainly composed of a microcomputer. The shift control controller 52 includes a throttle opening TVO detected by the throttle opening sensor 53 and a vehicle speed sensor 54 provided on the output shaft side of the continuously variable transmission 10. Based on the vehicle speed VSP and the rotation speed Ni of the input shaft 20 of the continuously variable transmission 10 detected by the input shaft rotation sensor 55, a target gear ratio according to the driving state of the vehicle is calculated, and the actual speed of the continuously variable transmission 10 is calculated. Is instructed to the stepping motor 4 such that the speed ratio of the motor 1 becomes equal to the target speed ratio. The vehicle speed sensor 54 outputs a value obtained by multiplying the output shaft rotation speed No of the continuously variable transmission 10 by a predetermined constant as the vehicle speed VSP.

As shown in FIG. 2, the shift control performed by the shift controller 52 includes a target tilt angle calculator 73 for calculating a target gear ratio in accordance with the throttle opening TVO and the vehicle speed VSP, and a vehicle speed VSP ( Tilt angle calculator 7 for determining the actual gear ratio from output shaft speed No) and input shaft speed Ni
1. Based on the deviation between the target gear ratio and the actual gear ratio,
An electronic feedback control based on integral control using an observer is performed to send a control amount STP to the step motor 4. The state estimation observer unit 72, the integrator 74,
The step converter 75 mainly performs multiplication of various gains and addition and subtraction of various signals.

Here, electronic feedback control by integral control using an observer is performed as follows.

The target tilt angle calculator 73 calculates a target tilt angle from the throttle opening TVO and the vehicle speed VSP based on a map (not shown) set in advance.

When the characteristics of the toroidal type continuously variable transmission 10 are represented as shown in FIG.
In this case, a and f in FIG. 3 are constants indicating characteristics of the tilt angle φ, and b and g are constants indicating characteristics of the axial displacement y of the trunnion 41. The constant can be identified from the input / output characteristics of the toroidal continuously variable transmission 10.

In FIG. 4, ω is a predetermined constant indicating the pole of the observer, K1 and K2 are observer gains, input A is a command value, and input B is an actual gear ratio.

The state estimating observer unit 72 may be configured in the same manner as in Japanese Patent Application No. 7-71495.

On the other hand, a deviation e is calculated from the target speed ratio from the target tilt angle calculation section 73 and the actual speed ratio from the tilt angle calculation section 71, and the deviation e is input to the integrator 74. Then, after adding the value obtained by multiplying the output of the integrator 74 by the predetermined gain C _{0 and the person} who multiplied the deviation e by the predetermined gain C ₁ , the output of the state estimation observer 72 is subtracted to obtain the command value. Is calculated.

Then, the value obtained by adding the output of the cam canceling feedback unit 70 to this command value is used as the step conversion unit 75.
Enter As disclosed in Japanese Patent Application Laid-Open No. 8-296722, the cam offset feedback unit 70 provides a valve displacement amount equal to the mechanical feedback amount by driving the step motor 4 to cancel the mechanical feedback amount. .

The step converter 75 calculates a control output value according to the command value, specifically, the number of steps STP of the step motor 4 based on a map shown in FIG. At this time, the step conversion unit 75 outputs the control output value S
TP is limited between a predetermined lower limit value Lowlim and an upper limit value Hilim so as not to exceed the displacement limit of the sleeve 5b of the shift control valve 5 shown in FIGS.

Further, in the step converter 75, when the command value or the control output value STP corresponding to the command value is less than a predetermined lower limit value (Lowmax or Lowlim) or exceeds an upper limit value (Himax or Hilim), the integration is performed. An integration stop command is sent to the integrator 74, and the integrator 74 stops the integration operation while the integration stop command is issued. That is, when the command value U is between the predetermined lower limit value Lowmax and the upper limit value Himax, the integrator 74 performs the integrating operation, while the command value U is less than the predetermined lower limit value Lowmax or exceeds the upper limit value Himax and the control output value While the STP has reached the lower limit value Lowlim or the upper limit value Hilim, the integration operation is temporarily stopped.

Therefore, according to the present invention, as shown by the solid line in FIG. 6, the control output value to the step motor 4 is set to the upper limit or the lower limit (lim in the figure) from the time Time = 0. When the opening is reduced by increasing the opening of the valve 5 to quickly shift the gear, and then reducing the opening of the transmission control valve 5 to a predetermined gear ratio, the upper limit or the lower limit is maintained until Time = 0.4. Then, when the target value is changed so as to be within the drive range of the step motor 4, the integration operation stops while the control output value is between the upper limit value and the lower limit value, and therefore the integral value increases regardless of the deviation e. Therefore, Time = immediately after changing the command value so that it is within the drive range
When the control output STP is within the drive range from 0.5, the opening amount of the shift control valve 5 is changed, so that the speed can be changed quickly, and in a continuously variable transmission having a follow-up control type mechanical feedback system, This makes it possible to suppress a decrease in followability due to an increase in the integral value.

On the other hand, in the above conventional example, as shown by the one-dot line in the figure, the integration operation is continued while the control output value STP is at the upper limit or the lower limit (lim in the figure). Becomes too large, and even if the command value changes from Time = 0.4, the control output value actually starts to change due to an excessive integral value after Time = 0.9, and the follow-up performance is reduced. Greatly reduced.

Further, when the control output value is not limited, as shown by the broken line in FIG. 6, although the response is improved, the sleeve 5b of the shift control valve 5 exceeds the limit value lim. It has an adverse effect such as deforming.

As described above, in the case of performing the electronic feedback control including the integral control in the continuously variable transmission having the follow-up control type mechanical feedback system, the control output value STP of the step motor 4 is set to the upper limit Hilim and the upper limit Hilim. In addition to preventing deformation of the shift control valve 5 by setting the lower limit value Lowlim, the integration operation is temporarily stopped when the control output value STP is at the upper limit value or the lower limit value. It is possible to suppress a decrease in follow-up performance due to an increase in the integral value as in the conventional example, and to further improve the control accuracy of the shift control.

Further, even if the relationship between the control output value and the valve opening amount shifts due to step-out of the step motor 4 and the control output value is continuously set to the upper limit value Hilim or the lower limit value Lowlim, the integration operation is stopped during this time. Therefore, it is possible to prevent the integral value from excessively increasing, and to prevent the following performance from being deteriorated.

In the above-described embodiment, the sleeve 5b of the shift control valve 5 is determined based on the control output value to the step motor 4.
Although not shown, the position of the sleeve 5b may be detected by a stroke sensor or the like, and an actuator such as the step motor 4 may be driven based on this position information. In this case, the position of the sleeve 5b Is the most Lo
Alternatively, when the maximum value is reached, the driving of the actuator is stopped, and at the same time, the integration operation is stopped.
In addition to obtaining the effect, even if the actuator such as the step motor loses synchronism, it is possible to prevent the displacement of the driving range.

In the above embodiment, the shift control controller 52 performs integral control, which is not shown. However, the present invention is applied to a device which performs PI control or PID control as in the conventional example. Is also good.

In the above-described embodiment, an example in which a toroidal type is used as the continuously variable transmission has been described. However, the same operation and effect can be obtained by applying the present invention to a V-belt type continuously variable transmission. .

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a shift control device for a continuously variable transmission, showing one embodiment of the present invention.

FIG. 2 is a block diagram of a transmission control controller.

FIG. 3 is a model of a toroidal-type continuously variable transmission also used for an observer.

FIG. 4 is a model showing an example of an observer.

FIG. 5 is a map showing a relationship between a command value and a control output value.

FIG. 6 is a graph showing the operation, showing the relationship between the valve displacement, the gear ratio and the integral value with time, wherein the solid line indicates the present invention, the dashed line indicates the conventional example, and the broken line indicates no limitation on the stepping motor drive amount. Show the case.

FIG. 7 is a cross-sectional view of a toroidal-type continuously variable transmission and a shift control valve.

FIG. 8 is a longitudinal sectional view of the toroidal-type continuously variable transmission.

FIG. 9 is a graph showing the relationship between the integrated value, the number of steps, the speed ratio, and time according to the conventional control.

FIG. 10 is a conceptual diagram showing a conventional example and showing a relationship between a displacement range of a sleeve of a shift control valve and a drive range of a step motor.

[Explanation of symbols]

 Reference Signs List 1 input cone disc 2 output cone disc 3 power roller 4 step motor 5 shift control valve 5a spool 5b sleeve 6 hydraulic cylinder 7 precess cam 8 link cam 10 stepless transmission 20 input shaft 41 trunnion 52 shift control controller 53 throttle opening sensor 54 Vehicle speed sensor 55 Input shaft rotation sensor 71 Tilt angle calculating unit 72 State estimation observer unit 73 Target tilt angle calculating unit 74 Integrator 75 Step converting unit

Claims (2)

[Claims] 1. A continuously variable transmission for continuously changing a speed ratio by a speed change mechanism driven by an actuator, a target speed ratio of the continuously variable transmission is calculated according to an operation state, and an actual speed ratio is calculated. Feedback control means for driving the actuator so that the actual gear ratio matches the target gear ratio; and a driving amount of the actuator exceeding a predetermined driving range. Wherein the drive amount of the actuator is at an upper limit value or a lower limit value of a predetermined drive range while the integration operation of the integration means is performed. A shift control device for a continuously variable transmission, comprising: an integration operation stopping means for stopping the operation. 2. A continuously variable transmission for continuously changing a gear ratio by a gear mechanism driven by an actuator, and calculating a target gear ratio of the continuously variable transmission in accordance with an operating state, and calculating an actual gear ratio. Feedback control means for driving the actuator such that the actual gear ratio matches the target gear ratio, and wherein the position of the transmission mechanism exceeds a predetermined displacement range. A shift control device for a continuously variable transmission, comprising: a drive amount restricting means for restricting a drive amount of the actuator so that the displacement amount of the transmission mechanism is not changed. A shift control device for a continuously variable transmission, comprising: integration operation stopping means for stopping the integration operation of the integration means while the value is at the value.