JP3301260B2 - Transmission control device for toroidal type continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input disk and an output disk which are arranged opposite to each other, and a stepless speed change of the rotation of the input disk in accordance with a tilt angle with respect to the two disks, and the rotation is transmitted to the output disk. The present invention relates to a shift control device for a toroidal-type continuously variable transmission including a shift unit including a pair of power rollers.

[0002]

2. Description of the Related Art A toroidal type continuously variable transmission mounted on an automobile is generally a double cavity type toroidal type continuously variable transmission in which two of the above-mentioned transmission units are arranged on the same shaft. The toroidal-type continuously variable transmission generally includes an input shaft to which an engine output is input, a pair of input disks rotatably supported with respect to the input shaft, and an input shaft arranged opposite to each of the input disks. A pair of output disks rotatably supported with respect to the shaft, a tiltable power roller disposed between a pair of opposed input and output disks and transmitting torque from the input disk to the output disk; A connecting member for integrally connecting a pair of output disks, a power roller disposed between the pair of flange portions provided on the input shaft and the input disks and acting on each of the input disks according to the magnitude of the input torque. It has a pressing means for changing the pressure contact force. By tilting the power roller, the rotation of the input disk is changed according to the tilt angle to the output disk. It is configured to shift to transmission to steplessly. In the toroidal-type continuously variable transmission described above, the tilting of the power roller is performed by the shift control device. Conventionally, various types of shift control devices have been known (for example, see Japanese Patent Application Laid-Open No. 62-289440). For example, there is a shift control device as shown in FIG.

[0003] As shown in FIG.
Are arranged so as to be sandwiched between an input disk 1 and an output disk (not shown) arranged opposite to each other, and are rotatably supported by support members called trunnions 4, respectively. That is, the power roller 2 is supported by the trunnion 4 by the eccentric shaft 5. Each trunnion 4 is supported by a transmission casing (not shown) so as to be rotatable and movable in the axial direction. Each trunnion 4 has a tilt shaft 6, moves in the axial direction of the tilt shaft 6, and can rotate about the tilt shaft 6.
A piston 7 is fixed to the tilt shaft 6 of the trunnion 4, and the piston 7 is slidably provided in a hydraulic cylinder 8 formed in a transmission casing. In the hydraulic cylinder 8, two cylinder chambers partitioned by the piston 7, that is, a speed-up cylinder chamber 8a and a deceleration-side cylinder chamber 8b are formed.

[0004] Each cylinder chamber 8a, 8b of the hydraulic cylinder 8
Communicates with the spool valve 10 through oil passages 9a and 9b. The spool 11 slidably disposed in the spool valve 10 is held at a neutral position by springs 12 disposed at both ends in the axial direction. The spool valve 10 has an Sa port at one end and an Sb port at the other end.
The pilot pressure Sa is supplied to the Sa port via the solenoid valve 13a, and the solenoid valve 13b is supplied to the Sb port.
Is supplied via the pilot pressure Sb. Spool valve 1
0 is a PL port communicating with the line pressure (oil pressure source), an A port communicating with the speed increasing cylinder chamber 8a via the oil passage 9a, a B port communicating with the speed reducing cylinder chamber 8b via the oil passage 9b, It has two T ports that communicate with the tank. The solenoid valves 13a and 13b are connected to the controller 14
It is configured to operate in response to a control signal output from.

[0005] A precess cam 1 is provided at the tip of one tilt shaft 6.
5 is connected, one end of a lever 16 pivotally connected at the center thereof contacts the precess cam 15, and the other end of the lever 16 is connected to a potentiometer 17. Potentiometer 17
Detects the axial displacement and tilt angle of the tilt shaft 6 of the trunnion 4 as a combined displacement amount, and outputs a detection signal to the controller 1.
Enter 4 The shift control device further includes various sensors such as a vehicle speed sensor 18, an engine rotation sensor 19, a throttle opening sensor 20, and the like.
The vehicle speed, engine speed,
A shift information signal such as a throttle opening is input to the controller 14.

In the toroidal type continuously variable transmission, the trunnion 4 is set at the neutral position (the position where the rotation center axis of the power roller 2 crosses the rotation center axes of the input disk 1 and the output disk).
When the trunnion 4 is displaced in the direction of the tilt axis (that is, the axial direction of the tilt axis 6), the trunnion 4 tilts around the tilt axis 6 in a direction and at a speed corresponding to the direction and the amount of displacement. The shift control is performed by utilizing the property that the shift is performed by the tilt.

Next, the operation of the transmission control device will be described.
This will be described with reference to the flowchart of FIG. At the time when the speed change operation is started, the trunnion 4 is
Is located at a so-called neutral position where the rotation center lines of the input disk 3 and the output disk intersect with each other. Until the engine starts and the engine stops, the controller 14
Performs the shift control of the main routine. First, the controller 14 calculates the target gear ratio e ₀ based on the gear information. The potentiometer 17 detects the speed ratio e and inputs it to the controller 14 (S1-1).

Next, the controller 14 responds to the deviation (ee ₀ ) between the gear ratio and the target gear ratio by using the solenoid valve 13.
A duty (duty) A to be output to a and a duty B to be output to the solenoid valve 13b are calculated by the following equations (S1-2). dutyA = 50% + G (e -e 0) dutyB = 50% -G (e-e 0) where, G is a proportionality constant as the feedback gain. The duty is O in pulse width modulation control.
It refers to the time ratio between N and OFF. That is, the duty (%) is given by the following equation. duty = (one cycle of solenoid ON time / solenoid operation cycle) × 100 Next, dutyA and dutyB are output to the solenoid valves 13a and 13b, respectively (S1-3).

Next, the operation of the transmission control device will be described. First, the controller 14 calculates the actual transmission ratio from the combined displacement of the trunnion 4 detected by the potentiometer 17, and calculates the deviation between the transmission ratio and the target transmission ratio. DutyA and dutyB set in accordance with
Output to 3a and 13b. Accordingly, pilot pressures Sa and Sb are supplied to both ends of the spool valve 10 from the solenoid valves 13a and 13b, respectively. At this time, when the gear ratio is on the deceleration side, the pilot pressure in the relationship of Sa> Sb is supplied, so the spool 11 shifts to the left in FIG. 4, and the oil passage 9a is connected to the pressure source via the PL port. The oil passage 9b communicates with the tank via the T port,
The pressure Pa of the oil passage 9a becomes larger than the pressure Pb of the oil passage 9b (Pa> Pb). As a result, the cylinder chambers 8a, 8b
4, the left trunnion 4 in FIG. 4 is displaced upward, and the right trunnion 4 is displaced downward. Along with this displacement, the trunnions 4 tilt around the tilt shaft 6, respectively, and the speed change operation is started to the speed increasing side. Before the gear ratio matches the target gear ratio, the magnitudes of the hydraulic pressures Pa and Pb of the two cylinder chambers 8a and 8b are reversed (Pa <Pb), and the trunnion 4 is displaced downward in the opposite direction, thereby displacing the tilt axial direction. Gradually become smaller. In the meantime, the speed ratio continues to shift to the speed increasing side. Then, the speed ratio may exceed the target speed ratio, but the feedback is repeated, so that the speed ratio eventually coincides with the target speed ratio. At that time, the displacement of the trunnion 4 in the tilt axis direction becomes zero, and the speed change is performed. The operation ends.

[0010]

As described above, in the transmission control apparatus of the toroidal type continuously variable transmission shown in FIG. 4, the speed ratio is combined with the displacement of the trunnions 4 and 4 in the tilt axis direction by the precess cam 15, and the potentiometer is used. 17, the magnitudes of Pa and Pb are reversed before the speed ratio matches the target speed ratio.

Considering, for example, the case where the speed ratio is on the deceleration side of the target speed ratio, when the magnitudes of Pa and Pb are reversed only when the speed ratio matches the target speed ratio, the speed change is performed. Even after the ratio matches the target gear ratio, the gearshift continues at a large rate of change toward the speed increasing side, so that the overshoot increases. However, as described above, in the transmission control device of the conventional toroidal-type continuously variable transmission shown in FIG.
Since the magnitudes of a and Pb are reversed,
Since the displacement of the trunnion in the axial direction of the trunnion gradually decreases and the rate of change of the speed ratio decreases, even if the speed ratio is shifted to the speed increasing side beyond the target speed ratio, the overshoot at that time is small. It will be.

However, when a step shift with a large shift width such as kick down is performed, as shown in FIG. 6C, the gear ratio (see the solid line) vibrates greatly and the target gear ratio (see the broken line). (See Reference). In the worst case, the speed ratio may diverge without converging to the target speed ratio. Under such circumstances, it is an issue how to realize shift control that does not cause overshoot even when a step shift with a large shift width is performed.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to prevent overshoot of the shift control by reducing the shift speed as the speed ratio approaches the target speed ratio, to thereby realize a step shift with a large shift width. Is to provide a speed change control device for a toroidal-type continuously variable transmission that quickly and reliably converges the speed ratio to the target speed ratio.

[0014]

The present invention is configured as follows to achieve the above object. That is, the present invention provides an input disk and an output disk which are disposed opposite to each other, and a pair of transmission disks which transmit the rotation to the output disk by continuously changing the rotation of the input disk in accordance with a change in the tilt angle with respect to the both disks. A state in which a power roller, a pair of trunnions rotatably supporting the power roller and displaceable in a tilt axis direction, a hydraulic cylinder having two cylinder chambers for displacing the trunnion in a tilt axis direction, and a spool in a neutral position A spool valve that selectively communicates each cylinder chamber with a hydraulic pressure source and a tank in a state where the cylinder chamber is shut off and the spool is displaced from the neutral position, and controls a pilot pressure acting on both ends of the spool. A target shift speed is set in accordance with a deviation between the shift ratio and the target shift ratio, A speed controller for controlling an output signal to the solenoid valve so that a pressure difference of a pilot pressure to be used is proportional to a difference between a shift speed and a target shift speed. Related to the device.

In the transmission control apparatus for a toroidal-type continuously variable transmission, the controller responds to a signal in which a deviation between the transmission ratio and the target transmission ratio exceeds the predetermined value to change the deviation between the transmission ratio and the target transmission ratio. A target shift speed is set accordingly, and an output signal to the solenoid valve is controlled so that a pressure difference between pilot pressures acting on both ends of the spool is proportional to a deviation between the shift speed and the target shift speed. The output signal to the solenoid valve is set so that the pressure difference between the pilot pressure acting on both ends of the spool is proportional to the difference between the gear ratio and the target gear ratio in response to the difference between the gear ratio and the target gear ratio being equal to or less than a predetermined value. Is controlled. Here, the shift speed can be calculated, for example, by dividing the change in the gear ratio detected at each program cycle of the controller by the program cycle.

The controller calculates a deviation between the actual transmission ratio and the target transmission ratio and outputs a signal corresponding to the deviation. The deviation between the transmission ratio and the target transmission ratio is determined by a predetermined value. Control mode selecting means for judging whether the difference is equal to or less than the predetermined value, selecting the normal mode when the difference is equal to or less than the predetermined value, and selecting the special mode when the difference exceeds the predetermined value; A target shift speed calculating means for calculating a target shift speed according to a signal input from the speed ratio deviation calculating means, sampling a difference between a currently detected speed ratio and a previously detected speed ratio in the special mode; Shift speed calculating means for calculating a shift speed by dividing by time, shift speed deviation calculating means for calculating a deviation between the shift speed and a target shift speed and outputting a signal corresponding to the deviation, and the normal mode The dut calculates a duty proportional to the input signal from the speed ratio deviation computing means when
and a duty calculating means for outputting y to the solenoid valve, calculating a duty proportional to a signal input from the shift speed deviation calculating means in the special mode, and outputting the duty to the solenoid valve.

[0017]

The shift control device for a toroidal-type continuously variable transmission according to the present invention is configured as described above and operates as follows. Since the shift speed depends on the displacement of the trunnion in the tilt axis direction, controlling the shift speed indirectly controls the displacement of the trunnion in the tilt axis direction. In this transmission control device, the target transmission speed is set according to the deviation between the transmission ratio and the target transmission ratio. Therefore, the target transmission speed becomes the maximum immediately after the start of the transmission, then gradually decreases, and the transmission ratio becomes smaller. It is set to be zero when it matches the target gear ratio. In addition, the controller controls the output signal to the solenoid valve so that the pressure difference between the pilot pressure acting on both ends of the spool valve is proportional to the deviation between the shift speed and the target shift speed. The shift speed is maximized by displacement in the tilt axis direction, and the shift speed converges to a set target shift speed while fluctuating therefrom. Accordingly, as the gear ratio approaches the target gear ratio, the gear speed fluctuates and decreases, and when the gear ratio substantially matches the target gear ratio, the gear speed becomes zero, so that overshoot in gear control is reliably prevented. be able to.

As described above, when the pressure difference between the pilot pressures acting on both ends of the spool valve is controlled so as to be proportional to the speed change speed, the speed change speed is set in a region where the deviation between the speed ratio and the target speed ratio is small. Since the size is reduced, there is a problem that accuracy is reduced due to restrictions such as the resolution of the potentiometer. However, in this transmission control device, when the deviation between the transmission ratio and the target transmission ratio is within a predetermined value, the control is switched to the conventional control, and the duty according to the deviation between the transmission ratio and the target transmission ratio is set to a solenoid valve. Output, the above problem is solved, and the control can be performed with high accuracy even in a region where the deviation is very small.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a toroidal-type continuously variable transmission according to an embodiment of the present invention; FIG. 1 is a flowchart showing a procedure of a shift control in a shift control device for a toroidal type continuously variable transmission according to the present invention, and FIG. 2 is a functional block diagram of a controller in the shift control device. Here, the shift control device of the toroidal type continuously variable transmission has substantially the same configuration as the conventional one shown in FIG. 4, and the difference between the two is in the control of the controller 14.

The controller 14, as shown in FIG.
Target speed ratio calculating means 2 for calculating a target speed ratio by inputting a detection value relating to the speed information detected by the speed information detector 21
2, trunnions 4 and 4 detected by potentiometer 17
The actual gear ratio is calculated by inputting the combined displacement amount of the tilting shafts 6,6, that is, the combined displacement amount of the axial displacement of the tilting shafts 6,6 and the tilting angle of the tilting shafts 6,6. Speed ratio calculating means 23, which calculates a deviation between the actual speed ratio and the target speed ratio, and outputs a signal corresponding to the deviation; a speed ratio deviation calculating means 24, which makes the difference between the speed ratio and the target speed ratio equal to or less than a predetermined value Control mode selecting means 25, which determines whether or not the deviation is equal to or less than the predetermined value, selects the normal mode, and selects the special mode if the deviation exceeds the predetermined value. A target shift speed calculating means 26 for calculating a target shift speed according to a signal input from the speed ratio deviation calculating means 24, that is, a target shift speed corresponding to a difference between the speed ratio and the target speed ratio; The currently detected gear ratio calculated by the ratio calculating means 23 and the previously detected gear ratio Shift speed calculating means 27 for calculating a shift speed difference between the gear ratio divided by the sampling time,
A shift speed deviation calculating means 28 for calculating a difference between the shift speed and the target shift speed and outputting a signal corresponding to the difference, and a duty proportional to a signal input from the speed ratio difference calculating means 24 in the normal mode. (Duty), that is, a duty proportional to the deviation between the gear ratio and the target gear ratio is calculated.
The duty is output to the solenoid valves 13a and 13b, and the duty proportional to the signal input from the shift speed deviation calculating means 28 in the special mode, that is, the duty proportional to the difference between the shift speed and the target shift speed is calculated. There is a duty calculating means 29 for outputting the duty to the solenoid valves 13a and 13b.

The shift information detector 21 includes sensors such as a vehicle speed sensor 18 for detecting a vehicle speed, an engine rotation sensor 19 for detecting an engine speed, and a throttle opening sensor 20 for detecting a throttle opening. The target speed ratio calculating means 22 calculates an optimum speed ratio determined by the vehicle speed, engine speed, throttle opening, etc. detected by the sensors 18, 19, 20 and sets the optimum speed ratio as the target speed ratio. The gear ratio calculating means 23 calculates the actual gear ratio by inputting the combined displacement of the trunnions 4 and 4 detected by the potentiometer 17.

Next, the procedure of the shift control in this shift control device will be described with reference to the flowchart of FIG. Before the shift operation is started, the trunnions 4, 4
Are the rotation center axes of the power rollers 2 and 2 and the input disk 3
And at the so-called neutral position where the rotation center axes of the output disk intersect.

First, a main routine is started, a shift information detector 21 detects shift information such as an engine speed, a throttle opening, a vehicle speed, and the like, and a target speed ratio calculating means 22 detects the shift information based on the detected shift information. Calculate the optimal gear ratio,
This is set as the target gear ratio e ₀ (S1). next,
Tilt axis 6 of trunnion 4 by potentiometer 17
Is calculated, and the speed ratio calculating means 23 calculates an actual speed ratio e at the present time from this synthesized displacement amount (S
2). Next, the deviation (ee) between the target speed ratio e ₀ calculated in step 1 and the actual speed ratio e calculated in step 2 is shown.
₀ ) is calculated by the gear ratio deviation calculating means 24, and the deviation (e) is calculated.
The control mode selection means 25 determines whether or not the absolute value of −e ₀ ) is equal to or less than a predetermined value e _s (S3). Deviation (e-e ₀₎
Is less than a predetermined value, the normal mode is set, and the same control as the conventional control shown in FIG. 5 is performed. That is, the duty proportional to the deviation between the speed ratio and the target speed ratio (e-e ₀₎ is calculated by the following equation (S4). dutyA = 50% + G (e -e 0) dutyB = 50% -G (e-e 0)

In step S3, that is, in step 3, if the absolute value of the deviation (e−e ₀ ) between the gear ratio and the target gear ratio is equal to the predetermined value e
When it exceeds _s switches to a special mode, the target shift speed phi ₀ corresponding to the deviation (e-e ₀₎ between the speed ratio and the target speed ratio is calculated by the target shift speed calculating means 26 (S5). That is, the target gear speed φ ₀ is given as a function g (e ₀ , e) of the gear ratio and the target gear ratio. Next, the shift speed φ is calculated from the following equation by the shift speed calculating means 27 (S6). That is, φ = (e ₁ −e ₂ ) / t Here, e ₁ is the detected value of the current gear ratio, e ₂ is the detected value of the previous gear ratio, and t is the sampling time. Next, the duty which is proportional to the deviation (φ−φ ₀ ) between the shift speed and the target shift speed is calculated by the duty calculating means 29 according to the following equation (S7). dutyA = 50% + G (φ−φ ₀ ) dutyB = 50% −G (φ−φ ₀ )

S4, ie, dutyA calculated in step 4
And dutyB when ordinary mode, that is, when the deviation between the speed ratio and the target speed ratio (e-e ₀₎ is small, are output solenoid valve 13a, to 13b. Further, dutyA and dutyB calculated in step 7 (S7) are:
In the special mode, that is, the deviation (e) between the gear ratio and the target gear ratio
−e ₀ ) is large, the solenoid valves 13a, 13a,
13b (S8). Then, the process returns to the start (S1) of the main routine, and the speed change operation is repeated again (S9).

Next, the shift operation of the shift control device will be described with reference to FIG. FIG. 3A is a graph showing a temporal change of a hydraulic pressure difference between the pilot pressures Sa and Sb acting on both ends of the spool valve 10, and FIG. 3B is a temporal change of a displacement of the trunnion 4 in the tilt axis direction. And (c) of FIG. 3 is a graph showing the change over time of the gear ratio.

In this transmission control device for a toroidal-type continuously variable transmission, the deviation (ee) between the speed ratio and the target speed ratio is determined.
₀ ), the target shift speed φ ₀ is set in accordance with the target shift speed φ ₀ , so that the larger the deviation (e−e ₀ ) between the shift ratio and the target shift ratio is, the larger the target shift speed φ ₀ is. the deviation (e-e ₀₎ becomes smaller target transmission speed phi ₀ the smaller the, when the speed ratio e is equal to the target speed ratio e _0, since the deviation (e-e ₀₎ is zero , The target shift speed φ ₀ also becomes zero.

On the other hand, the shift speed φ depends on the displacement of the trunnion 4 in the tilt axis direction. That is, the larger the displacement of the trunnion 4 in the tilt axis direction, the larger the transmission speed φ, and the smaller the displacement of the tilt axis direction, the smaller the transmission speed φ. Therefore, controlling the shift speed φ indirectly controls the displacement of the trunnion 4 in the tilt axis direction. Therefore, when the target gear ratio e ₀ changes as shown by the broken line in FIG. 3C, the target displacement of the trunnion 4, that is, the target gear speed φ ₀ becomes the broken line in FIG. Will be changed as shown by. That is, the target shift speed φ ₀ is set to a maximum immediately after the start of the shift, then gradually decreases, and becomes zero when the speed ratio e matches the target speed ratio e ₀ .

A description will now be given of a case where the kick down is performed while the vehicle is running at the maximum speed increase ratio. When the kick down is performed, the target gear ratio e ₀ greatly steps up from the speed increasing side to the decelerating side as shown by a broken line in FIG. At this time, the deviation between the gear ratio and the target gear ratio (e−
Since the absolute value of e ₀ ) exceeds the predetermined value e _s , the control mode is switched to the special mode, and the target gear speed φ ₀ is set according to the deviation (e−e ₀ ) between the gear ratio and the target gear ratio. . Then, the deviation between the shift speed and the target shift speed (φ−φ
₀ ) is output to the solenoid valves 13a and 13b, respectively. That is, dutyB becomes larger than dutyA (dutyA <dutyB), the hydraulic pressure Pb is supplied to the deceleration-side cylinder chamber 8b, and the hydraulic pressure Pb is supplied from the speed-increase-side cylinder chamber 8a.
a is discharged, Pa <Pb, and the left trunnion 4 in FIG. 4 starts to be largely displaced downward from the neutral position.
As the trunnion 4 is displaced downward, the shift speed φ approaches the target shift speed φ ₀ , so that the duty A and the duty
The difference from B becomes smaller, and the oil pressure difference between the two cylinder chambers 8a, 8b gradually decreases. Accordingly, the downward displacement of the trunnion 4 is also reduced, and the downward displacement of the trunnion 4 stops.

Since the speed change speed φ at that time is slightly larger than the target speed change speed φ ₀ , duty A and duty
The magnitude of yB is reversed (dutyA> duty)
B). When the duty A becomes larger than the duty B, the left trunnion 4 in FIG. 4 starts to be displaced upward, and the trunnion 4 approaches the neutral position. And, while the left trunnion 4 is displaced upward,
The speed change speed φ decreases, and again the target speed change speed φ ₀
Will be less than. Then, dutyA and du again
The size of tyB is reversed (dutyA <dutyB),
The direction in which the trunnion 4 is displaced is also the opposite direction. In this manner, as shown in FIG.
Every time the magnitude relationship of yB, that is, the pressure difference between the pilot pressures Sa and Sb acting on both ends of the spool valve 10 repeats a small change, the trunnion 4 oscillates up and down little by little as shown in FIG. While being displaced, the amplitude gradually decreases, and the trunnion 4 approaches the neutral position, during which the gear ratio also approaches the target gear ratio. Then, when the trunnion 4 returns to the neutral position, the gear ratio e matches the target gear ratio e _{0 as shown} in FIG. As described above, since the trunnion 4 moves as shown by the solid line in FIG. 3B, the gear ratio e (see the solid line) smoothly changes to the target gear ratio e ₀ as shown in FIG. 3C. (Refer to the broken line), and the overshoot of the shift control can be reliably prevented.

Further, the deviation (e-
When e ₀ ) becomes equal to or less than the predetermined value, the control is switched from the control according to the deviation (φ−φ ₀ ) between the shift speed and the target shift speed to the same control as the conventional one. That is, the control of the solenoid valve 13a, the output signal to 13b as pilot pressure Sa acting on both ends of the spool valve 10, the pressure difference Sb is proportional to the deviation (e-e ₀₎ between the speed ratio and the target gear ratio Switch to the conventional control. Since the gear ratio e can be detected more accurately than the gear speed φ, even in a region where the deviation (e−e ₀ ) between the gear ratio and the target gear ratio is very small,
The shift control can be performed with high accuracy.

[0032]

The transmission control apparatus for a toroidal-type continuously variable transmission according to the present invention is configured as described above.
It has the following effects. That is, when the deviation between the speed ratio and the target speed ratio is equal to or smaller than a predetermined value, the transmission control device for the toroidal type continuously variable transmission has a pressure difference between the pilot pressure acting on both ends of the spool valve and the speed ratio and the target speed ratio. The output signal to the solenoid valve is controlled so as to be proportional to the deviation of the gear ratio.When the deviation between the gear ratio and the target gear ratio exceeds the predetermined value, the target signal is controlled in accordance with the deviation between the gear ratio and the target gear ratio. The shift speed is set, and the output signal to the solenoid valve is controlled so that the pressure difference between the pilot pressure acting on both ends of the spool is proportional to the difference between the shift speed and the target shift speed. That is, since this shift control device sets the target shift speed in accordance with the deviation between the shift ratio and the target shift ratio, the target shift speed becomes the maximum value during shifting, and then gradually decreases, It is set to be finally zero.
Moreover, the controller controls the output signal to the solenoid valve so that the pressure difference between the pilot pressures acting on both ends of the spool is proportional to the difference between the shift speed and the target shift speed, so that the shift speed converges to the target shift speed. As the gear ratio approaches the target gear ratio, the gear ratio matches the target gear ratio when the gear speed becomes zero. Therefore, this shift control device can surely prevent overshoot of shift control, and can achieve stable shift responsiveness without adding a new sensor. Further, in this transmission control device, in a region where the deviation between the transmission ratio and the target transmission ratio is extremely small, a signal corresponding to the deviation between the transmission ratio and the target transmission ratio is input to the solenoid valve as before, The gear ratio can be accurately controlled even in a region where the deviation is small.

[Brief description of the drawings]

FIG. 1 is a flowchart showing shift control in a shift control device for a toroidal type continuously variable transmission according to the present invention.

FIG. 2 is a functional block diagram of a controller in a shift control device for a toroidal-type continuously variable transmission according to the present invention.

FIG. 3 is a graph showing a shift operation in the shift control device of the toroidal type continuously variable transmission according to the present invention.

FIG. 4 is a schematic view of a conventional shift control device for a toroidal-type continuously variable transmission.

FIG. 5 is a flowchart showing shift control in a shift control device of a conventional toroidal-type continuously variable transmission.

FIG. 6 is a graph showing a shift operation in a shift control device of a conventional toroidal-type continuously variable transmission.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input disk 2 Power roller 4 Trunnion 6 Tilt axis 8 Hydraulic cylinder 8a Speed-up side cylinder chamber 8b Deceleration-side cylinder chamber 10 Spool valve 11 Spool 13a Solenoid valve 13b Solenoid valve 14 Controller 24 Gear ratio deviation calculating means 25 Control mode selecting means 26 target shift speed calculating means 27 shift speed calculating means 28 shift speed deviation calculating means 29 duty calculating means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 61/00-61/24 F16H 15/38

Claims (3)

(57) [Claims] An input disk and an output disk disposed opposite to each other, and a pair of power transmitted to the output disk by continuously changing the rotation of the input disk in accordance with a change in a tilt angle with respect to the both disks. Rollers, a pair of trunnions rotatably supporting the power roller and displaceable in the tilt axis direction, a hydraulic cylinder having two cylinder chambers for displacing the trunnions in the tilt axis direction, and a state in which the spool is in the neutral position. A spool valve that selectively closes the cylinder chambers to a hydraulic pressure source and a tank when the cylinder chamber is shut off and the spool is displaced from the neutral position, and controls a pilot pressure acting on both ends of the spool. A solenoid valve, and a target shift speed is set according to a deviation between the shift ratio and the target shift ratio, and acts on both ends of the spool. A transmission control device for a toroidal-type continuously variable transmission, comprising: a controller that controls an output signal to the solenoid valve so that a pressure difference between the pilot pressure and the target transmission speed is proportional to a difference between the transmission speed and a target transmission speed. . 2. The controller according to claim 1, wherein the controller sets a target shift speed in accordance with a difference between the speed ratio and the target speed ratio in response to a signal in which the difference between the speed ratio and the target speed ratio exceeds the predetermined value.
The output signal to the solenoid valve is controlled so that the pressure difference between the pilot pressures acting on both ends of the spool is proportional to the difference between the shift speed and the target shift speed. An output signal to the solenoid valve is controlled so that a pressure difference between pilot pressures acting on both ends of the spool in response to a predetermined value or less is proportional to a deviation between a speed ratio and a target speed ratio. Item 3. A shift control device for a toroidal-type continuously variable transmission according to item 1. 3. The controller according to claim 1, wherein the controller calculates a deviation between the actual transmission ratio and the target transmission ratio and outputs a signal corresponding to the deviation. Control mode selecting means for judging whether the difference is equal to or less than the predetermined value, selecting the normal mode when the difference is equal to or less than the predetermined value, and selecting the special mode when the difference exceeds the predetermined value; A target shift speed calculating means for calculating a target shift speed according to a signal input from the speed ratio deviation calculating means, sampling a difference between a currently detected speed ratio and a previously detected speed ratio in the special mode; Shift speed calculating means for calculating a shift speed by dividing by time, calculating a shift between the shift speed and the target shift speed, and outputting a signal corresponding to the difference; and in the normal mode Calculates the duty proportional to the signal input from the speed ratio deviation calculating means.
To the solenoid valve, and in the special mode, calculates a duty proportional to a signal input from the shift speed deviation calculating means, and outputs the duty to the solenoid valve. The shift control device for a toroidal-type continuously variable transmission according to claim 2.