JP2003336732A - Transmission control device for toroidal CVT - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To perform speed change with a constant response regardless of operating conditions. A controller determines a target gear ratio from an accelerator opening and a vehicle speed, and determines a target tilt angle. Then, the stroke x of the trunnion 36 is determined based on the difference between the current tilt angle and the target tilt angle, and the stroke control by the hydraulic control valve 52 is performed. The controller 80 performs feedback control of the tilt angle θ and the stroke x. The feedback gains kθ and kx are changed according to the input rotation speed, the input / output disk pressing force, the tilt angle, and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toroidal transmission member having an input / output disk and a roller for transmitting power between the input / output disks by frictional engagement therebetween.
A toroidal CVT having a shift control section for changing the tilt angle of the roller and controlling the gear ratio by offsetting the rotation axis of the roller from a position where the rotation axis of the roller and the rotation axis of the input / output disk are orthogonal to each other. The present invention relates to a shift control device.

[0002]

2. Description of the Related Art Conventionally, various types of continuously variable transmissions (CVTs) have been known, among which there is a toroidal CVT. This toroidal CVT has an input / output disk and a roller for transmitting power between the input / output disks by frictional engagement between them.

The input / output disk has a shape close to a triangular pyramid as a whole, and its slope is cut in an arc shape. The input / output discs are arranged so that their protruding central portions face each other, and the cross section of the input / output discs combined is in a semicircular shape cut out from both sides. Therefore, when the rollers make contact with the peripheral side of the input disc and the inside of the output side disc, the rotation of the part away from the axis of the input disc can be transmitted to the side close to the axis of the output disc, and the reduction ratio is small. Therefore, the gear ratio can be determined by changing the contact position.

The roller is rotatably supported by a member called a trunnion so that the position of contact with the input / output disk can be changed. The rotation angle of the trunnion about the axis of rotation of the roller is inclined with respect to the input / output disk. (Tilt angle), and in the toroidal CVT, the gear ratio is determined by the tilt angle.

When the tilt angle is changed, the trunnion is moved in a direction perpendicular to the input / output disk rotation shaft. That is, the rotation axis of the roller is offset from the position where the rotation axis of the roller and the rotation axis of the input / output disk intersect at right angles. This offset amount is called a trunnion stroke. As a result, a force is applied to the roller in the direction of changing the tilt angle, which changes the tilt angle of the roller to control the gear ratio.

Therefore, in the toroidal CVT,
The tilt angle, which is the rotation angle of the roller supported by the trunnion about the trunnion axis, and the axial offset amount (trunnion stroke) of the trunnion are detected. Then, the gear ratio is obtained from the tilt angle, and the target position displacement of the roller in the trunnion axis direction (offset amount = trunnion stroke) is calculated based on the deviation between the gear ratio and the target gear ratio.
Then, the trunnion is displaced by the hydraulic actuator so that the trunnion stroke (offset amount) matches the target trunnion stroke (offset amount). In this way, the gear ratio control is performed by controlling the offset amount based on the deviation of the tilt angle (gear ratio) from the target. Note that performing such control as electronic feedback control is disclosed in Japanese Patent Laid-Open No. 08-233085.

[0007]

As described above, the gear ratio control in the toroidal CVT is performed. This control controls the tilt angle by controlling the offset amount, and the control is comparatively performed. It's complicated. Further, since the offset amount is normally controlled by the hydraulic pressure and is controlled by controlling the hydraulic control valve, it is difficult to perform the control as a whole accurately. For example, depending on the input torque of the transmission, the tilt angle or the trunnion stroke (offset amount) is changed from the hydraulic control valve command value of the toroidal CVT.
Frequency response up to. Therefore, there is a problem that appropriate control cannot be performed unless the control is changed according to the change of the input torque.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a toroidal CVT gear shift control device capable of appropriately controlling a gear ratio.

[0009]

SUMMARY OF THE INVENTION The present invention is directed to a toroidal transmission member having an input / output disk and a roller for transmitting power between the input and output disks by frictional engagement between the input / output disk, a rotary shaft of the roller, and a rotary shaft. In a toroidal CVT that has a shift control unit that changes the roller tilt angle by offsetting the roller rotation axis from a position where the rotation axes of the output discs are orthogonal to each other, And a feedback control unit that feeds back the roller rotation axis offset amount, and the feedback gain for at least one of the roller tilt angle and the roller rotation axis offset amount is set to the input / output disk pressing force and the roller tilt. It is characterized in that it is changed based on any one or more of the turning angle and the input rotational speed.

As described above, according to the present invention, the feedback gain of the roller tilt angle or the roller rotation shaft offset amount is changed according to the operating conditions. As a result, the gear ratio control can be performed with an appropriate feedback gain under the operating conditions at that time, and the gear shift responsiveness and stability can be kept constant.

Further, the feedback gain for each of the roller tilt angle and the roller rotation axis offset amount is based on at least one of the input / output disk pressing force, the roller tilt angle, and the input rotation speed. It is preferable to change. Thereby, more appropriate control can be performed.

Further, it is preferable that the roller tilt angle is detected by a roller tilt angle or a gear ratio.

The input / output disc pressing force is preferably detected by the input / output disc pressing force or input torque.

Further, the roller rotation axis offset amount is
It is preferable to detect by any one of the roller rotation axis offset amount, the roller tilt angle change amount, the gear ratio change amount, and the input rotation speed change amount.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a toroidal type C according to the embodiment.
The overall structure of the VT is shown. That is, two sets of input disks 30a and 30b are coupled to the input shaft 10 that is rotated based on the rotation of the engine. Each of the input disks 30a and 30b has an opening formed in the center and has a shape that gradually projects from the outer side toward the center side, and the slope has a substantially arcuate cross section in the axial direction. The input disk 30a is located on the left side in the figure,
The input disk 30b is located on the right side in the figure, and both of them are located so that their protruding centers face inward.
Output disks 40a and 40b having substantially the same shape are arranged so as to face the input disks 30a and 30b, respectively. That is, the input disk 30a
And the output disk 40a are arranged to face each other, and the input disk 3
0b and the output disk 40b are arranged to face each other. Therefore, in the axial cross section, the slopes of the input disk 30a and the output disk 40a form a pair of semicircles, and the input disk 30b and the output disk 40b form another pair of semicircles.

Rollers 35a-1, 35a-2 are sandwiched between the input / output disks 30a, 40a, and rollers 35b-1, 35b- are provided between the input / output disks 30b, 40b.
2 is pinched. That is, the rollers 35a-1, 3
One side of 5a-2, 35b-1, 35b-2 is in contact with the input disks 30a, 30b, and the other side is the output disk 4
0a, 40b are contacted, and the rotational torque of the input disks 30a, 30b is transmitted to the output disks 40a, 40b.
Further, the rollers 35a-1 and 35a-2 are supported by the trunnions 36a-1 and 36a-2, respectively, and the rollers 35b-1 and 35b-2 are respectively connected to the trunnion 36b.
-1, 36b-2. This trunnion 36a-1, 36a-2, 36b-1, 36b-2
Has an axis in a direction perpendicular to the plane of the drawing, is movable in the axial direction, and is rotatable about the axis. Also, the trunnions 36a-1 and 36a-
2, 36b-1, 36b-2 are fixed in radial positions of the shafts, and rollers 35a-1, 35a-2, 35b-.
1, 35b-2 are input / output disks 30a, 40a, 30
It is designed not to separate from b and 40b.

The input shaft 10 is hydraulically pressed (end load).
It is connected to the mechanism 20. This end load mechanism 20
By receiving the hydraulic pressure inside and pressing the input disks 30a and 30b toward the output disks 40a and 40b, respectively,
I / O disks 30a, 40a, I / O disk 30
b, 40b, a narrow pressure is generated between the rollers 35a-1, 35a-2, 35b-1, 35b-2 at a predetermined pressure to the input / output disks 30a, 40a, 3b.
It is sandwiched between 0b and 40b. This prevents slippage between the input / output disks 30a, 40a, 30b, 40b and the rollers and maintains a traction state. In addition, axis 2
Reference numeral 5 indicates the same rotation as the input shaft 10, and the shaft 25 rotates the input disks 30a and 30b. The input disks 30a and 30b are connected to the shaft 25 via a thrust bearing, and are movable in the axial direction of the shaft 25.

The output disks 40a and 40b are rotatably supported by the shaft 25 via bearings. An output gear 45 is connected between the output disks 40a and 40b and rotates together with the output disks 40a and 40b. A counter gear 60 is meshed with the output gear 45, and an output shaft 70 is connected to the counter gear 60. Therefore, the output disks 40a, 40b
The output shaft 70 rotates with the rotation of.

Further, the toroidal CVT is provided with a hydraulic piston chamber, and the trunnions 36a-1 and 36a- are provided by the hydraulic pressure from the hydraulic piston chamber.
The displacements (trunnion stroke: roller offset amount) of 2, 36b-1 and 36b-2 in the trunnion axis direction are controlled. This trunnion 36a-1, 36a-2, 36
The gear ratio is changed by controlling the trunnion stroke (roller offset amount) of b-1 and 36b-2. The stroke (roller offset amount) of the trunnions 36a-1 and 36a-2 is the trunnion 36a-
The line connecting the centers of 1, 36a-2 is the input / output disk 30,
Complementary through the center of 40, trunnion 3
The trunnion strokes (roller offset amounts) of 6b-1 and 36b-2 are the trunnions 36b-1 and 36b-2.
The lines connecting the centers of the input and output disks 30 and 40 are complementary to each other.

Here, regarding the change of the gear ratio, FIG.
It will be described based on. Note that FIG. 2 is a view of the input disk 30 as seen from the output disk 40, and shows only one input disk 30 and one roller 35, respectively. FIG. 2A shows a case where the roller 35 is not displaced (trunnion stroke = 0).
The axis of rotation 5 passes through the center of the input disc 30. When shifting, the trunnion 36 is offset in its axial direction. For example, as shown in FIG.
The input disk 30 is offset in the direction of rotation (upper side in the figure). As a result, a force is applied to the roller 35 in the circumferential direction of the input disk 30 at the moved position, and a force (tilting force) to move the roller 35 to the peripheral side of the input disk 30 is applied. And roller 3
When the offset amount (trunnion stroke) of 5 returns to 0, the position where the roller 35 contacts the input disk 30 is displaced outward in the radial direction. As a result, the contact position of the roller 35 with the output disk 40 is displaced inward in the radial direction, and the gear ratio changes (upshifts).
In the figure, downward (the side where the input disc moves away)
By offsetting the trunnion 36 to, the trunnion 36 tilts in the opposite direction and a downshift is performed.

FIG. 3 shows a configuration for this gear ratio control. In FIG. 3, one input disk 30, two rollers 35-1 and 35-2, and two trunnions 36-1 and 36-2 are shown.

As described above, the hydraulic piston chamber 50 has a pair of piston chambers 50-1 and 50-2 for performing complementary operations to the trunnions 36-1 and 36-2.
A hydraulic control valve 52 is connected to the piston chambers 50-1 and 50-2, and the hydraulic pressure supplied to the hydraulic piston chambers 50-1 and 50-2 is controlled by the control of the hydraulic control valve 52. , The trunnions 36-1 and 36-2 are controlled (roller offset amount).

Then, the tilt angle θ of the trunnion 36 is detected by the tilt angle sensor 37, the stroke x is detected by the stroke sensor 38, and the stroke x is supplied to the controller 80.

The controller 80 is also supplied with information about the accelerator opening and the vehicle speed.
Determines the target gear ratio from the accelerator opening and the vehicle speed, and determines the target stroke based on the deviation between the target gear ratio and the gear ratio corresponding to the tilt angle θ detected by the tilt angle sensor 37. And based on this target stroke,
The hydraulic control valve 52 is controlled to control the stroke x of the trunnion 36. As a result, the gear ratio at that time obtained from the tilt angle matches the target gear ratio, and the gear ratio control ends.

Here, in such a shift control, basically, the shift control only needs to feedback control only the tilt angle θ (gear ratio). However, the stroke x corresponds to the differentiation of the tilt angle θ, and has a damping effect of suppressing vibration in tilt control. Therefore, stroke feedback control is also performed so that the stroke x detected by the stroke sensor 38 matches the target stroke. The roller 35 and the input / output disk 3
If the contact positions of 0 and 40 are known, the relationship between the gear ratio and the tilt angle is determined only by the geometrical shape, so the gear ratio can be replaced by the tilt angle, and the tilt angle can be replaced by the gear ratio.

In FIG. 3, the gear ratio is indicated by the tilt angle sensor 3
Although it is detected by the tilt angle of 7, the gear ratio may be obtained from the input shaft rotational speed and the output shaft rotational speed. Instead of the stroke of the trunnion 36, the tilt angle change amount, the input rotation speed change amount, and the gear ratio change amount may be used.

In the present embodiment, the feedback gain of the trunnion stroke and tilt angle in the controller 80 is changed according to the operating conditions.

FIG. 4 shows a configuration for feedback control in the controller 80. As described above, the target gear ratio is determined based on the accelerator opening and the vehicle speed, and the tilting angle command value corresponding thereto is determined. This tilt angle command value is input to the subtractor 81. The detected value of the tilt angle actually measured is input to the subtractor 81, and the deviation θ between the target and the current tilt angle is calculated and output by the subtracter 81.

The deviation Δθ which is the output of the subtracter 81 is input to the tilt angle feedback gain setting unit 82. The tilt angle feedback gain setting unit 82 multiplies the deviation Δθ of the tilt angle by a predetermined feedback gain kθ,
Kθ × Δθ which is the feedback input value of the tilt angle feedback control is calculated. This kθ × Δθ becomes the hydraulic control amount corresponding to the target value of the trunnion stroke determined according to the difference between the target gear ratio and the current gear ratio.

The output kθ × Δθ of the tilt angle feedback gain setting unit 82 is input to the subtractor 83. The subtractor 83 includes a feedback input value k that is a target value of the trunnion stroke obtained by multiplying the measured current trunnion stroke x by a predetermined feedback gain kx in the stroke feedback gain setting unit 84.
xx is also input. This feedback gain input value kx × x is also the hydraulic control amount corresponding to the target value of the trunnion stroke.

As a result, the difference between the target control amount kθ × Δθ of the trunnion stroke and the control amount kxx × x based on the actual trunnion stroke x is calculated, and this difference is used as the control amount of the flow control valve 85. Is supplied to. That is, feedback control for the trunnion stroke is performed.

The hydraulic pressure controlled by the flow control valve 85 is supplied to the trunnion 36 of the toroidal CVT 100, and the stroke thereof is controlled. By this stroke control, the tilt angle is changed, and the gear ratio control is performed so as to match the target gear ratio. The components shown in FIG. 4 are the feedback gains kθ and kx.
Corresponds to the identification model for setting.

In this embodiment, the feedback gains kθ and kx are set according to the operating conditions at that time. A method of designing this control system will be described with reference to FIG. First, the provisional control gain before optimal design that can stabilize the controlled object is set (S11). In this state, the target tilt angle command value, which is the control input for each operating condition, that is, the predetermined input / output disk pressing force (or input torque), input rotation speed, and gear ratio, is set at a predetermined frequency. Model identification is performed using a signal having a substantially constant gain, for example, an M-sequence signal as an input value, and data of the trunnion stroke and the tilt angle as an output value (S12). That is, a linear model (identification model) near the operating point is identified for each operating condition (input torque, tilt angle, rotation speed).

A model consisting of the flow control valve to be controlled and a variator model is back-calculated from the obtained identification model and the gain before the optimum design (S13).

Using the model representing the obtained controlled object, each operating condition (input torque (disk pressing force Fc),
Optimal feedback gains kθ and kx are obtained by designating target control performance (responsiveness and stability) for each tilt angle (θ) and rotation speed (Ni) (S14).

In FIG. 5, only the proportional gain is shown for simplification, but each gain of the PID control may be used. Alternatively, the internal constant of a 2-input 1-output controller may be used as one controller.

Further, the controller may be gain-scheduled by an LMI controller (robust controller capable of gain scheduling with parameters) having the above operating conditions as parameters. Further, the operating oil temperature may be added as an operating condition for gain setting.

FIG. 6 shows a comparison according to the input rotational speed when the speed is increased in the actual device. The upper figure shows the case where the input torque is 100 Nm and the output rotation speed is 1000 rpm, and the lower figure shows the input torque 100 Nm and the output rotation speed 20.
The case of 00 rpm is shown. The gains kθ and kx have considerably different values depending on the input rotation speed, but the responsiveness to the target tilt angle is almost the same, and the effectiveness of the control of this embodiment can be understood.

Next, a method of storing a gain map which becomes a problem when the feedback gain set for each driving condition is actually used in an ECU (electronic control unit) of a vehicle will be described.

The method of calculating the feedback gain may be a method of calculating the gain by interpolation using a map for each operating condition, but the number of operating conditions, the number of feedback signals, and the type of gain (proportional, differential, and integral gains). Only needs a map, so the map capacity is large.
Therefore, the capacity can be reduced by calculating the feedback gain using a function having each operating condition as a parameter. This function is as shown in FIG. 7, for example, when there are three kinds of operating conditions, that is, the disc pressing force Fc, the input rotation speed Ni, and the tilt angle θ. In the figure, the left side shows the tilt angle feedback gain kθ, and three types of disc pressing forces Fc1, Fc2, Fc3 are shown.
The values of kθ with respect to Ni and θ in FIG. Also, in the figure, the right side shows the trunnion stroke feedback gain kx, and shows the values of kx with respect to Ni and θ in the three types of disc pressing forces Fc1, Fc2, and Fc3.

Further, these feedback gains kθ,
The following is a mathematical expression of kx.

[0043]

## EQU00001 ## k.theta. = F.theta. (Fc, Ni, .theta.) Kx = fx (Fc, Ni, .theta.) (1) In this equation (1), k.theta.
kx is a stroke feedback gain, Fc is a disc pressing force, Ni is an input rotation speed, and θ is a tilt angle.

As an example, the equation (1) can be expressed by the following linear multiple regression equation.

[0045]

Kθ = α ₀ + α ₁ Fc + α ₂ Ni + α ₃ θ kx = β ₀ + β ₁ Fc + β ₂ Ni + β ₃ θ (2) where α ₀ , α ₁ , α ₂ , α ₃ , β ₀ , β ₁ , β ₂ , and β ₃ are
It is a coefficient.

As described above, in the present embodiment, the tilt angle feedback gain kθ and the trunnion stroke feedback gain kx are changed according to the operating conditions (disk pressing force Fc, input rotational speed Ni, tilt angle θ). . As a result, the tilt angle control can be more appropriately performed, and the gear shift control can be performed with a substantially constant response during gear shifting for speeding up and decelerating, regardless of operating conditions.

In the above example, the two feedback gains kθ and kx are determined based on the three operating conditions, but any number of operating conditions may be used as long as they are 1 or more.
Further, only one of the feedback gains kθ and kx may be changed depending on the driving condition. Furthermore, it is also suitable to add the operating oil temperature to the operating conditions.

As described above, either the gear ratio or the tilt angle may be detected, and the input torque may be used as the operating condition instead of the input / output disc pressing force.

[0049]

As described above, according to the present invention,
Change the feedback gain of the roller tilt angle or roller rotation axis offset according to the operating conditions. As a result, the gear ratio control can be performed with an appropriate feedback gain under the operating conditions at that time, and the gear shift responsiveness and stability can be kept constant.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a toroidal CVT.

FIG. 2 is a diagram illustrating tilting of a roller.

FIG. 3 is a diagram showing a configuration of trunnion stroke and tilt angle control.

FIG. 4 is a diagram showing a configuration of an identification model.

FIG. 5 is a diagram showing a design procedure.

FIG. 6 is a diagram showing a response at the time of shifting.

FIG. 7 is a diagram showing values of feedback gains kθ and kx.

[Explanation of symbols]

10 input shaft, 30 input disc, 40 output disc, 50 hydraulic piston chamber, 60 counter gear, 7
0 output axis, 80 controller.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI Theme Coat (reference) F16H 63:06 F16H 63:06 (72) Inventor Hiroyuki Nishizawa 41st in Nagakute, Aichi-gun, Aichi Prefecture 1 In the Toyota Central Research Institute Co., Ltd. (72) Inventor Masataka Osawa 1 in 41, Yokoshiro Nagakute-cho, Aichi-gun, Aichi-gun 1 In Toyota Central Research Institute Co., Ltd. (72) Inventor Yuji Iwase Toyota-cho, Toyota City, Aichi Prefecture No. 1 Toyota Motor Co., Ltd. (72) Inventor Naoki Moriguchi No. 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Car Co., Ltd. F-term (reference) 3J552 MA06 NA01 NB01 PA20 PA54 RA02 SA44 SB02 TA02 VA24W VA24Y VA26W VA27Z VA32W VA34W VA37Z VA74W VA74Y VB01Z VD02Z

Claims (5)

[Claims] 1. A toroidal transmission member having an input / output disk and a roller for transmitting power between the input / output disks by frictional engagement in the middle thereof, and a rotation axis of the roller and a rotation axis of the input / output disk are orthogonal to each other. In a toroidal CVT that has a shift control unit that controls the gear ratio by changing the tilt angle of the roller by offsetting the rotary shaft of the roller from the position, the tilt angle of the roller and the offset amount of the rotary shaft of the roller. And a feedback control section for feeding back the feedback gain for at least one of the roller tilt angle and the roller rotation axis offset amount, the input / output disc pressing force, the roller tilt angle, and the input rotation speed. A toroidal CVT shift control device characterized in that it is changed based on any one or more. 2. The apparatus according to claim 1, wherein feedback gains for each of the roller tilt angle and the roller rotation axis offset amount are calculated as input / output disk pressing force, roller tilt angle, and input rotation speed. A toroidal CVT shift control device characterized in that it is changed based on any one of the above. 3. The toroidal CVT shift control device according to claim 1, wherein the roller tilt angle is detected by a roller tilt angle or a gear ratio. 4. The toroidal CVT gear shift according to claim 1, wherein the input / output disc pressing force is detected by an input / output disc pressing force or an input torque. Control device. 5. The apparatus according to claim 1, wherein the roller rotation shaft offset amount is a roller rotation shaft offset amount, a roller tilt angle change amount, a gear ratio change amount, and an input rotation. A toroidal CVT shift control device characterized in that it is detected by any one of a number of changes.