JP2003301936A - Change gear ratio control device for continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a change gear ratio control device for a toroidal continuously variable transmission using an instruction value of a step motor for generating shifting as a speed instruction which achieves stable control without generating a collision of a trunnion with a tilting stopper. <P>SOLUTION: The continuously variable transmission for continuously changing a change gear ratio, the input number of revolutions detecting means for detecting the input number of revolutions on the basis of an input revolution signal cycle synchronized with the input revolution to the continuously variable transmission, and an output number of revolution detecting means for detecting the output number of revolution on the basis of an output revolution cycle synchronized with the output revolution from the continuously variable transmission are provided. Change gear ratio is computed on the basis of the input number of revolutions and the output number of revolutions in the timing for updating a signal having a longer cycle in the input revolution signal cycle and the output revolution signal cycle, and change gear ratio of the continuously variable transmission is controlled on the basis of the computed change gear ratio. <P>COPYRIGHT: (C)2004,JPO

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, and more particularly to a shift control device for accurately detecting a gear ratio in a low vehicle speed range.

[0002]

2. Description of the Related Art As a conventional shift control device for a continuously variable transmission, for example, a technique disclosed in Japanese Patent Laid-Open No. 2000-283285 is known. In the technique described in this publication, when the gear ratio is detected in a low vehicle speed range such as when starting or stopping, the rotation cycle of the input rotation speed or the output rotation speed to the transmission is longer than the control cycle for calculating the gear ratio. Determine if Then, there is disclosed a technique in which the driving force control based on the gear ratio is performed with high accuracy by fixing the gear ratio to the maximum gear ratio without calculating the gear ratio when the control cycle is long.

[0003]

However, the above-mentioned prior art has the following problems. That is, during normal control of the continuously variable transmission, the actual gear ratio, which is the current gear ratio, is detected, and the drive of the gear shift actuator is controlled by feedback control so that the actual gear ratio follows the target gear ratio. . However, in the above-mentioned conventional technology, an accurate gear ratio cannot be detected when the vehicle speed is low.
There was a problem that feedback control could not be performed.

Further, when the gear ratio is fixed to the maximum value without performing feedback control at low vehicle speed as in the prior art, deviation of the gear ratio must be taken into consideration.

Here, for example, in a toroidal type continuously variable transmission, a mechanical tilt stopper is provided as a means for regulating the tilt angle. In actual gear shifting, the tilting stopper is not contacted to regulate the tilting angle, and the tilting stopper is designed not to come into contact with the tilting stopper by the shift control. This is for the following reason. That is, each trunnion is provided with a mechanical synchronization mechanism for achieving tilt synchronization. Here, there is a manufacturing variation in the position of the tilt stopper, which causes the trunnion to come into contact with the tilt stopper, causing slippage between the input / output disk and the power roller, and synchronization between the trunnions. This is because there is a risk of collapse. On the other hand, in terms of vehicle performance, it is desirable that the shift range be as wide as possible. Therefore, it is necessary to minimize the clearance between the tilt stopper position and the tilt angle limit position by control.

However, if the maximum gear ratio is fixed and the deviation of the gear ratio is taken into consideration, it is necessary to keep a large clearance at the tilt angle limit position, which is an obstacle to downsizing the transmission. There was a problem that it would end up.

The present invention has been made in view of the above problems, and an object thereof is to achieve feedback control of a gear shift actuator by accurately detecting a gear ratio even in a low vehicle speed range. It is an object of the present invention to provide a shift control device for a continuously variable transmission that can perform the above.

[0008]

In order to solve the above-mentioned problems, the present invention provides a continuously variable transmission mechanism capable of continuously changing the gear ratio and an input signal cycle synchronized with the input rotation to the continuously variable transmission mechanism. An input side rotation speed detecting means for detecting the input rotation speed based on the input rotation speed; and an output side rotation speed detecting means for detecting the output rotation speed based on an output signal cycle synchronized with the output rotation of the continuously variable transmission mechanism, Both the input signal and the output signal are updated at the update timing of the signal having the longer one of the input signal cycle and the output signal cycle, and the gear ratio is calculated from the updated input rotation speed and output rotation speed, and calculated. The gear ratio control device for the continuously variable transmission mechanism controls the gear ratio of the continuously variable transmission mechanism based on the determined gear ratio.

[0009]

According to the present invention, even if the input / output speed of the continuously variable transmission is different, the stable operation is achieved by updating both the input / output signals at the update timing having a long cycle. The gear ratio can be obtained. This allows
It is possible to perform feedback control of the gear ratio even at a low vehicle speed, and accurate gear ratio control can be achieved without changing the control content depending on the vehicle speed.

[0010]

(First Embodiment) FIG. 1 is a skeleton diagram of a toroidal continuously variable transmission 10 (hereinafter referred to as TCVT) according to a first embodiment of the present invention, and FIG. 2 is a cross section of the TCVT 10. , And the configuration of the shift control system.

Engine rotation (not shown) as a power source provided on the left side in FIG.
It is input to the CVT 10. This torque converter 12
As is generally known, the pump impeller 12
a, a turbine runner 12b, and a stator 12c, and particularly the torque converter 12 of the first embodiment is provided with a lockup clutch 12d. Further, a torque transmission shaft 16 arranged coaxially with the output rotation shaft 14 of the torque converter 12 is provided, and the torque transmission shaft 16 is provided.
The first toroidal transmission unit 18 and the second toroidal transmission unit 2
0 and are arranged in tandem.

These first and second toroidal transmission units 18,
Reference numeral 20 denotes a pair of a first input disk 18a and a first output disk 18 whose opposing surfaces are toroidal curved surfaces.
b, the second input disk 20a, the second output disk 2
0b and power rollers 18c, 18d and 20c, 20d which are frictionally contacted between the facing surfaces of the first input / output disks 18a, 18b and the second input / output disks 20a, 20b.

The first toroidal transmission unit 18 is arranged on the left side of the torque transmission shaft 16 in the drawing, and the second toroidal transmission unit 20 is arranged on the right side of the torque transmission shaft 16 in the drawing. The first input disk 18a and the second input disk 20b are arranged inside each other.

On the other hand, the first and second output disks 18b, 2
0b is spline-fitted to the output gear 28 that is relatively rotatably fitted to the torque transmission shaft 16, and the rotational force transmitted to the first and second output disks 18b and 20b is applied to the output gear 28 and the output gear 28. It is transmitted to the counter shaft 30 via the meshed input gear 30a, and further transmitted to the output shaft (not shown) via the rotational force output path.

A loading cam device 34 is provided outside the first input disk 18a. The output rotation of the torque converter 12 is input to the loading cam device 34 via the forward / reverse switching device 40, and a pressing force corresponding to the input torque is generated by the loading cam device 34. The loading cam 34a of the loading cam device 34 is used for the torque transmission shaft 16
And is engaged with the torque transmission shaft 16 via a thrust bearing 36.

A disc spring 38 is provided between the second input disk 20a and the right end portion of the torque transmission shaft 16 in the figure. Therefore, the pressing force generated by the loading cam device 34 acts not only on the first input disc 18a but also on the second input disc 20a via the torque transmission shaft 16 and the disc spring 38, and the disc spring 38. The preload generated by the action acts on the second input disc 20a and also acts on the first input disc 18a via the torque transmission shaft 16 and the loading cam device 34.

The forward / reverse switching device 40 includes a double pinion type planetary gear mechanism 42, a forward clutch 44 capable of engaging the carrier 42a of the planetary gear mechanism 42 with the output rotary shaft 14, and a ring gear 42b of the planetary gear mechanism 42. And a reverse brake 46 that can be fastened to the housing 22.

In the forward / reverse switching device 40, by engaging the forward clutch 44 and releasing the reverse brake 46, the rotation in the same direction as the engine rotation is TC.
By inputting to the VT 10, releasing the forward clutch 44 and engaging the reverse brake 46,
Rotation in the opposite direction is input.

The power rollers 18c, 1 provided on the first toroidal transmission section 18 and the second toroidal transmission section 20.
8d, 20c, and 20d are arranged symmetrically with respect to the central axis C. Each power roller has a shift control valve 56 as a shift control device and a hydraulic actuator 50.
Via, through which the rotation of the first and second input disks 18a, 20a is steplessly changed and transmitted to the first and second output disks 18b, 20b.

FIG. 2 is a mechanical block diagram of a hydraulic system for controlling the shift of the TCVT 10. The power roller 20c is supported by the trunnion 23 from the back surface. Trunnion 2
3 is connected to the servo piston 51 of the hydraulic servo 50, and is connected to the oil in the cylinder 50a in the hydraulic servo 50 and 50b.
It is displaced in the axial direction due to the differential pressure of the oil inside.

The cylinders 50a and 50b are connected to the Hi side port 56Hi and the Low side port 56Low of the shift control valve 56, respectively. This shift control valve 56 allows the line pressure to flow to the Hi side port 56Hi or the Low side port 56Low by the displacement of the spool 56S in the valve, and the drain 56D from the other port.
The pressure difference in the hydraulic servo is changed by letting oil flow out. The spool 56S is connected to the step motor 52 and a recess cam 55 described later by a link structure.

The precess cam 55 is attached to one of the four trunnions, and the power roller 20a.
The vertical displacement and the tilt angle of the power roller are converted into the displacement of the link. The displacement of the spool 56S is determined by the displacement of the step motor and the displacement transmitted (feedback) by the recess cam 55.

The TCVT 10 moves the trunnion 23 up and down from the equilibrium point, so that the power roller 20c
And a difference occurs in the rotational direction vectors of the input / output disks 20a and 20b, and the tilting causes the vector difference to change the speed. When the gear shift is steady, the displacements of the power roller 20c and the trunnion 23 return to the equilibrium point, and the spool 56S
The valve is closed at the neutral point. Further, the plurality of trunnions 23 are provided with tilt stoppers 24 that regulate tilt angles. This allows
Prevents excessive tilting of the power roller.

The precess cam 55 is the power roller 20c.
The negative tilt angle is fed back to the displacement of the spool 56S to compensate the deviation of the tilt angle from the target value. At the same time, the displacement of the power roller 20c and the trunnion 23 from the equilibrium point is also negatively fed back to the displacement of the spool 56S. As a result, damping effect is provided in the transitional state of gear shifting, and hunting of gear shifting is suppressed. Here, the reaching point of the gear shift is determined by the displacement of the step motor 52, and a series of gear shifting processes will be described below. By changing the step motor displacement, the spool 56S is displaced and the valve is opened. As a result, the differential pressure of the servo piston 51 changes, and the trunnion 23 is displaced in the axial direction from the equilibrium point, whereby the power roller tilts. At the time when the tilt angle of the power roller corresponds to the displacement of the step motor, the spool 56S returns to the neutral point and the shift is completed.

FIG. 3 shows TCVT1 in the present embodiment.
Shift control controller 6 for controlling the gear ratio of 0 to a target value
It is a block diagram containing 0. In the TCVT 10, the tilt angle φ changes according to the step motor drive speed command value v, and this dynamic characteristic is expressed in a block diagram.

[Step Motor and TCVT] In FIG. 3, the step motor 52 has the function of integrating the step motor drive speed v to the step motor drive position u, and is displaced in proportion to the number of steps. In FIG. 4, the displacement x of the spool valve, the step motor drive position u (t),
The relationship between the axial displacement y (t) of the trunnion and the tilt angle φ (t) of the power roller is shown. Here, in the trunnion 23,
A tilt stopper 24 is provided. The maximum displacement of the step motor drive position corresponding to the maximum tilt angle φmax when abutting against the tilt stopper 24 is Umax. still,
Details of the tilt stopper 24 are described in, for example, Japanese Patent Laid-Open No. 6-0
For example, see Japanese Patent Publication No. 34007.

The gear ratio of the toroidal type continuously variable transmission is calculated from the rotation speed ratio G (= ω _i / ω ₀ ) of the rotation speed ω _i of the input disk to the transmission and the rotation speed ω ₀ of the output disk. The following relationship is established between the gear ratio G and the current tilt angle φ.

[Formula 1] Here, θ and η are constants determined by the structure of the toroidal type continuously variable transmission.

In the shift control of the toroidal type continuously variable transmission, it is necessary to detect the tilt angle φ of the power roller. Therefore, the tilt angle is calculated using the above equation 1 from the detected gear ratio. At this time, the rotation speed of the input / output disk is detected by, for example, a rotation speed sensor that detects irregularities of a gear that rotates together with the input / output disk. Details of the rotation speed sensor will be described later.

For the step motor drive speed v and the step motor drive position u,

[Formula 2] Have a relationship. Note that Ts is a control cycle, and the step motor drive position u is an integrated value of the step motor drive speed v for a predetermined time.

The dynamic characteristic in which the tilt angle φ changes according to the step motor drive position u can be expressed by the following equation.

[Formula 3] Here, a2 is a constant determined by the recess cam 55 and the link ratio when the axial displacement of the trunnion 23 feeds back to the valve 56 position via the links 53 and 54. a1 is when the precess cam 55 is rotated by the tilt of the power roller 20c and is fed back to the valve 56 position via the links 53 and 54,
It is a constant determined by the recess cam 55 and the link ratio. b is a constant determined by the link ratio and the screw lead of the step motor 52. g is the valve gain.

Further, f is calculated by the following equation.

[Formula 4] Note that θ, η, and R ₀ are constants determined by the structure of the TCVT 10. That is, how much the power roller tilts per unit time depends on the tilt angle φ at that time.
And the output disc rotation speed ω ₀ .

Here, from the relationship between the gear ratio G and the tilt angle φ shown in the equation (1), the tilt angle φ can be predicted by the gear ratio G. Therefore, a low-dimensional model for estimating the remaining trunnion axial displacement y and the step motor drive position u is shown below.

[Formula 5] [Shift control controller] Next, the shift control controller 6
0 will be described. The shift control controller 60 includes a state observer 61, a compensator 62, a gear ratio calculation unit 70,
The target gear ratio calculation unit 64 calculates the target gear ratio Gref from the accelerator opening and the vehicle speed.

(State Observer) The state observer 61 will be described. If the estimated value of w of equation (5) and w _e, is represented by the following equation.

[Formula 6] Here, y ^ is the trunnion axial displacement estimated value, and u ^ is the step motor drive position estimated value. h1 and h2 are observer gains.

Since the tilt angular velocity dφ, which is the input to the state observer of the above equation (6), cannot be directly detected, the state conversion is performed by the following equation.

[Formula 7] Here, q is a quasi-state estimator. Differentiating both sides of the equation (7) and substituting the equation (6) for collection, the following equation is obtained.

[Formula 8] Here, since f is a time-varying value, the observer gain h
F is removed by setting 1 and h2 as follows.

[Formula 9] Therefore, the observer A _obs has the following formula.

[Formula 10] That is, the state observer restores the state estimation amount w from the quasi-state estimation amount q by calculating the equation (8) obtained by performing the state conversion instead of directly calculating the equation (6).

(Compensator) Next, the compensator 62 will be described. The step motor drive speed v is calculated by the following equation.

[Formula 11] K is a switching gain, and by making this value sufficiently large, the influence of the constant σ ₀ can be almost ignored.

Next, σ is given by the following equation.

[Equation 12] Here, ξ is a damping coefficient and ω is a natural frequency. Gref
Is a target gear ratio obtained from the accelerator depression amount and the vehicle speed. The first and second differentials of the gear ratio G are shown below.

[Formula 13] Based on the equation (12), the step motor drive speed v is output so as to follow the target gear ratio Gref. Gear shifting is performed by driving the step motor 52 based on the output step motor driving speed.

(Gear ratio calculating unit) Next, the gear ratio calculating unit 70
Will be described. 5 is a model diagram of the input rotation speed sensor 57a and the output rotation speed sensor 58a for calculating the gear ratio G (ω _i / ω _o ), and FIG. 6 is a block diagram showing the configuration of the gear ratio calculating unit 70.

As shown in FIG. 5, the input rotation speed sensor 57a reads the unevenness of the input gear 57 which rotates integrally with the input disk 20a, thereby outputting the input pulse signal. Similarly, the rotation of the output disk 20b is transmitted to the output shaft via the reduction gear, and the unevenness of the output gear 58 that rotates integrally with the output shaft is read by the output rotation speed sensor 58a, thereby outputting the output pulse signal. Is output. The rotation speed of the output disk 58 is calculated by converting from the reduction ratio of the reduction gear or the like.

The structure of the gear ratio calculating section 70 shown in FIG. 6 will be described. Reference numeral 71 denotes a first calculator that calculates the input / output speed from the input / output side pulse signals output from the input / output speed sensors 57a and 58a. Reference numeral 72 is a filter for synchronizing and smoothing the rotation speed output from the first calculating unit 71. 73
Is a second calculator for calculating the gear ratio from the synchronized and smoothed rotation speeds. A low-pass filter 74 further smoothes the calculated gear ratio.

The synchronization and smoothing filter 72 will be described in detail below. FIG. 7 is a flowchart showing the control of the synchronization and smoothing filter 72.

In step 101, it is judged whether or not the pulse signal on the input side has been output. If it is output, the process proceeds to step 103, and if it is not output, step 10 is executed.
Go to 2. Here, the output of the pulse signal refers to the output start time of the convex signal of the gear or the output start time of the recess signal.

In step 102, it is judged whether or not the output side pulse signal is outputted. If it is outputted, the process proceeds to step 104, and if not outputted, step 105.
Go to.

In step 103, Kin = Kin + 1.

In step 104, Kout = Kout + 1.

In step 105, Kin ≠ 0 and Kout
It is determined whether or not 0 and both Kin and Kout are 0.
If not, the process proceeds to step 107, and if both are 0, the process proceeds to step 106. Here, if Kin ≠ 0 and Kout ≠ 0, it means that both the pulse signals of the input / output gears have been updated at least once.

In step 106, flag = 1 is set.

In step 107, flag = 0 is set.

At step 108, Kin and Kout are set to 0.
To update.

In step 109, it is determined whether or not flag = 0. If it is 0, the process proceeds to step 110, and otherwise the process proceeds to step 111.

At step 110, the input speed ω_input
(k) is the input speed signal ω_input (k-1) of the previous control, and the output speed ω_output (k) is the output speed ω_outpu of the previous control.
It is output as t (k-1) and the gear ratio G (k) = G (k-1).

At step 111, the input rotation speed ω_input
(k) and the output rotation speed ω_output (k) are calculated.

At step 112, the input rotation speed signal G
(k) = ω_input (k) / ω_output (k).

In step 113, k = k + 1 is set, and this control is terminated.

The input side gear 57 and the output side gear 58 do not rotate at the same speed, and the number of teeth of each gear may be different (for example, in the present embodiment, the number of teeth of the input side gear 57 is 12, Since the number of teeth of the output side gear 58 is 21), the input / output pulse signals are not output at the same timing.

That is, steps 101 to 10
In 4, when either the input side or the output side outputs a pulse signal, either Kin or Kout is always 0. In this case, flag is set to 0 in step 107. Then, step 109 to step 110
In, the previous control value is used for the input / output speed. When both the input and output pulse signals are output, it is determined that both Kin and Kout are not 0 in step 105, flag is set to 1 in step 106, and step 1
At 08, both Kin and Kout are updated to 0. Then, step 109 → step 111 → step 112
To input rotation speed ω_input (k) and output rotation speed ω_outp
Update ut (k) (corresponding to claims 1 and 2).

Steps 101 to 105 correspond to the cycle determining means described in the claims.

Basically, it is considered that the output side gear has a later pulse update timing at low vehicle speed, but the input side pulse signal has a longer pulse update timing depending on the number of teeth of the input / output side gear. In some cases. Therefore, by updating the input / output rotation speed only when both the input and output pulse signals are updated within a certain control cycle, it is possible to synchronize with the longer update timing as a result.

The above control will be described with reference to FIG. FIG. 8 is a time chart showing changes in the input / output pulse signal and the angular velocity.

In the case of the first embodiment, the pulse signal on the input side is synchronized with the signal on the output side where the signal period becomes long. As shown in FIG. 8 (a), the input side pulse signal is (a),
It is updated at the timing of (b), (c) .... on the other hand,
The output side pulse signal is updated at the timings (α), (β), (γ), ... Therefore, as shown in FIG. 8B, the pulse signal on the input side is not updated at (a), but is maintained until (α) which is the pulse signal update timing on the output side. Update to pulse signal. Similarly, the pulse signal on the input side is the update timing of the pulse signal on the output side.
It is maintained until (β) and updated at (β). By thus achieving synchronization, as shown in FIG. 8C, it is possible to obtain the input / output rotation speed with which the pulse signals are synchronized.

Next, experimental results of the above control will be shown. Figure 9
Is a time chart showing the relationship between vehicle speed and input / output rotation speed. The vehicle speed in FIG. 9A is a low vehicle speed, specifically, 4
(Km / h) or less. FIG. 9B is a diagram showing the relationship between the input rotation speed ωi and the output rotation speed ωo when the vehicle speed changes in this way.

FIG. 10 shows a time chart when the gear ratio G is calculated based on the result shown in FIG. Figure 10
(A) is the speed ratio G from the input speed ωi and the output speed ωo
Is a value calculated as it is. FIG. 10 (b) is shown in FIG.
It is a value obtained by cutting a peak other than the range of the gear ratio that can be actually taken, such as the area indicated by the arrow in (a). Figure 10
(C) is a value obtained by calculating the gear ratio G from the input / output rotation speed when the synchronization and smoothing filter 72 of the first embodiment is used.

Comparing FIG. 10 (b) and FIG. 10 (c), it can be seen that a stable gear ratio can be obtained by using the synchronization and smoothing filter 72.

Here, in the case of having the vibration as shown in FIG. 10 (b), in the prior art, it was necessary to reduce the cutoff frequency of the low pass filter in order to eliminate such vibration. At this time, the cutoff frequency needs to be adjusted between the effect of the filter and the dimension of the filter. A filter with a low cut-off frequency requires a higher filter dimension for effective filtering, but a filter with a higher dimension has a large computational load, and there is a delay between the value detected by the sensor and the value after filtering. There are two problems that is large.

However, in the first embodiment, the gear ratio is calculated using the value obtained by synchronizing the input / output speed signal with the synchronization / smoothing filter 72, and the low-pass filter 74 filters the value. By doing so, it is not necessary to use a filter with a high dimension, so the calculation load is small. Further, it is possible to obtain the effect that the response delay due to filtering is small.

The low pass filter 74 will be described below. Low-pass filter 74 according to the first embodiment
Are three filters (filter1, fi) depending on the output speed ωo.
lter2, filter3).

[Formula 14] Here, the filter uses Butterworth Filter. αn and βn (n = 1,2,3) are constants determined by the time constant set for each filter. ωo (max) is the maximum output rotation speed at which filtering is performed by the synchronization and smoothing filter 72, and values obtained by dividing the output rotation speed ωo from 0 to ωo (max) are ωo (min), ωo (mid1), ωo (mid2). Where ωo (min) <ωo (mid1) <ωo (mid2) <ω
It is o (max).

FIG. 11 shows the results of filtering by filters 1 to 3. In the figure, the solid line is a filtered value after passing through the sync and smoothing filter 72, and the dotted line is a filtered value after passing through the sync and smoothing filter 72.

Here, filter3 has the largest time constant,
Since the response delay is also relatively large, the smoothest gear ratio can be obtained. Therefore, it is effective when the vehicle speed is low and the rotation speed is very low. On the other hand, when a vehicle speed is obtained to some extent, rapid changes are considered to be small. Therefore, it is possible to avoid a response delay by reducing the time constant like filter2 and filter1. That is,
Optimum filtering can be performed by using the filters 1 to 3 according to each output rotation speed (corresponding to claim 3).

As the above-mentioned filter, an event drive filter which updates the time constant of the filter only when the vehicle speed is low may be used. That is, when flag is 1, the filter is

[Formula 15] (A and b are constants, q is a variable that is changed depending on the value of k)
Is calculated and updated. On the other hand, when the flag becomes 0, it is not updated until the next pulse and the time constant is maintained (claim 4).
Equivalent to).

With this configuration, the time constant automatically adapts to the value at low vehicle speed, and the longer the pulse interval, the larger the time constant, and the shorter the pulse interval, the smaller the time constant.

As described above, by using the configuration of the present embodiment, it is possible to calculate a stable gear ratio even at a low vehicle speed, and perform feedback control of the gear ratio in a wide vehicle speed range. can do.

[Brief description of drawings]

FIG. 1 is a skeleton diagram showing a toroidal type continuously variable transmission according to an embodiment.

FIG. 2 is a schematic diagram showing a cross section of a toroidal-type continuously variable transmission and a configuration of a shift control system in an embodiment.

FIG. 3 is a shift control controller 60 that controls the gear ratio of the toroidal type continuously variable transmission according to the embodiment to a target value.
It is a block diagram containing.

FIG. 4 is a model diagram showing the relationship among the displacement amount x of the spool valve, the step motor drive position u (t), the axial displacement y (t) of the trunnion, and the tilt angle φ (t) of the power roller.

FIG. 5 is a model diagram showing a configuration of an input / output rotation speed sensor in the embodiment.

FIG. 6 is a block diagram showing a configuration of a gear ratio calculation unit in the embodiment.

FIG. 7 is a flowchart showing a gear ratio calculation control in the embodiment.

FIG. 8 is a time chart showing the gear ratio calculation control in the embodiment.

FIG. 9 is a diagram showing a relationship between vehicle speed and input / output rotation speed in the embodiment.

FIG. 10 is a diagram illustrating a specific example of shift control calculation control in the embodiment.

FIG. 11 is a diagram showing a filtering result by the low-pass filter of the shift control calculation unit in the embodiment.

[Explanation of symbols]

10 Toroidal type continuously variable transmission 12 Torque converter 12a Pump impeller 12b turbine runner 12c stator 12d lockup clutch 14 Output rotation axis 16 Torque transmission shaft 18,20 toroidal transmission 22 housing 23 trunnion 24 Tilt stopper 28 Output gear 30 counter shaft 30a input gear 34 Loading cam device 36 Thrust bearing 40 Forward / reverse switching device 42 Planetary gear mechanism 44 forward clutch 46 Reverse brake 50 hydraulic servo 51 Servo piston 52 step motor 53,54 links 55 Precessum 56 shift control valve 56S spool 56D drain 60 Shift controller 61 State Observer 62 Compensator 63 Gear ratio detector 64 Target Gear Ratio Calculation Unit 70 Gear Ratio Calculation Unit 71 1st calculation part 72 Synchronization / Smoothing filter 73 Second calculator 74 Second calculator 75 Low-pass filter (ButterworthFilter)

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Claims (4)

[Claims] 1. A continuously variable transmission mechanism capable of continuously changing a gear ratio, and input rotation speed detection means for detecting an input rotation speed based on an input rotation signal cycle synchronized with an input rotation to the continuously variable transmission mechanism. An output rotation speed detection means for detecting an output rotation speed based on an output rotation signal cycle synchronized with an output rotation of the continuously variable transmission mechanism, and a longer cycle of the input rotation signal cycle and the output rotation signal cycle. A speed change ratio of the continuously variable transmission mechanism is calculated based on the calculated speed ratio and the speed ratio is calculated from the input speed and the output speed. Ratio control device. 2. The gear ratio control device for a continuously variable transmission according to claim 1, wherein a cycle determining means for determining which of the input rotation signal cycle and the output rotation signal cycle is longer, the longer cycle determination means. And a gear ratio control means for calculating a gear ratio based on the input / output rotation signal at the timing of updating the signal cycle, and a gear shift control for performing gear shift control of the continuously variable transmission mechanism based on the calculated gear ratio. A gear ratio control device for a continuously variable transmission, comprising: 3. The gear ratio control device for a continuously variable transmission according to claim 1, further comprising a low-pass filter having a cut-off frequency as an input, the gear ratio calculated by said gear ratio calculating means being provided. A variable speed low-pass filter that increases the cut-off frequency of the low-pass filter when the detected input speed or output speed increases and decreases it when the detected input speed or output speed decreases. Ratio control device. 4. The toroidal type continuously variable transmission according to claim 3, wherein at least one of the detected input speed and output speed is greater than a preset speed that represents a low vehicle speed range. And a low vehicle speed region determining means for determining whether or not it is small, and when it is determined to be in the low vehicle speed region, the cutoff frequency of the low-pass filter is updated to the cutoff frequency changed according to the input rotation speed or the output rotation speed. Cut-off frequency updating means, and a gear ratio control means for a continuously variable transmission mechanism.