JP3515219B2 - Transmission control device for continuously variable transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a continuously variable transmission (hereinafter referred to as
The present invention relates to a shift control device for a continuously variable transmission, which is suitable for use in, for example, a vehicle, which performs a gear ratio feedback control using a hydraulic control valve.

[0002]

2. Description of the Related Art Generally, for example, a belt type CVT for a vehicle.
Is a fixed pulley part, a movable pulley part, and a primary side pulley and a secondary side pulley having a hydraulic servo provided on the movable pulley part and having a continuously variable effective diameter. And a drive belt. Then, the oil pressure generated by the oil pressure source is adjusted to the oil pressure on the secondary side of the CVT (hereinafter, simply referred to as secondary side pressure) according to the transmission torque by the secondary side hydraulic control valve, and the hydraulic servo of the secondary side pulley is controlled. Supply. On the other hand, in order to change the winding radius of the drive belt and change the gear ratio, the secondary side pressure is adjusted by the primary side hydraulic control valve, and the hydraulic pressure on the primary side of the CVT (hereinafter simply (Referred to as the primary side pressure). Thus, the CVT continuously changes the rotation of the engine and transmits it to the wheels.

Here, the primary hydraulic control valve and the secondary hydraulic control valve are controlled by an electronic control unit. The electronic control unit inputs a vehicle speed, a throttle opening, etc., determines an appropriate target gear ratio according to the operating conditions of the vehicle, and feedback-controls the gear ratio of the CVT. In addition, in this way CV
A device for electronically controlling T is disclosed in, for example, JP-A-63-3032.
No. 58 publication.

[0004]

Generally, there are a flow rate control valve and a pressure control valve as an actuator for controlling the shift of a CVT. When the pressure control valve is used, the operation amount is the primary side pressure. In the steady state, the speed ratio R, the relationship of the hydraulic ratio _P R = 1 primary side pressure _P 1/2 primary side pressure _{P 2} and the torque ratio _{T R} = the input torque _{T 1} / maximum torque transfer _{T MAX} is you express by: .

P _R = f (R, T _R ) (1)

The speed ratio change speed dR / dt is proportional to the difference ΔP ₁ from each hydraulic pressure in the steady state expressed by the following equation.

ΔP ₁ = P ₁ −P ₂ · P _R (2)

When feedback control of the actual gear ratio R to the target gear ratio R _{S is performed} , in order to eliminate the deviation, a proportional gain is applied to the deviation, a so-called proportional calculation, or a deviation is multiplied by an integral gain to perform integration, a so-called integral calculation. Etc. are included.
In addition, a feedforward element may be combined in parallel with the feedback element in order to improve followability with respect to the target value.

Since the integral value obtained by the above-described integral calculation reflects the past deviation, if the shift operation condition of the CVT to be controlled changes suddenly, there is a delay in following the target gear ratio. For example, a state where the deviation is zero at a certain integrated value, that is, a state where ΔP ₁ = 0 in the above formula (2) is realized, the driver depresses the accelerator, the engine torque increases,
CVT input torque increases. At this time, assuming that the target gear ratio has not changed, the control is first performed in accordance with the input torque.
The secondary pressure P ₂ is increased. Therefore, Δ in the above equation (2)
P ₁ ≠ 0 and the actual gear ratio changes.

On the other hand, as a shift control actuator,
When the flow control valve is used, the actual gear ratio hardly changes under the above conditions. When the deviation is 0, the flow control valve is in the fully closed state, so that even if the secondary pressure or the transmission torque changes, the primary pressure changes as a reaction and the above formula (1) is automatically established. This is because.

As described above, in the case of using the pressure control valve, if the general integral arithmetic processing is performed as in the case of using the flow rate control valve, the followability to the target value is remarkably increased. There was a problem that it got worse.

The present invention has been made in order to solve the above-mentioned problems, and in a feedback control system using a pressure control valve as an actuator for gear shift control, control with good followability to a target value is possible. An object of the present invention is to provide a shift control device for a continuously variable transmission.

[0013]

According to a first aspect of the present invention, there is provided a transmission control device for a continuously variable transmission, wherein a rotation speed detection device detects rotations of a primary pulley and a secondary pulley of the continuously variable transmission. Means, an actual speed ratio calculating means for calculating an actual speed ratio from the ratio of the rotational speeds from the rotational speed detecting means, a required load amount detecting means for detecting a load amount required for the engine, and at least the required load. Target speed ratio determining means for sequentially determining the target speed ratio based on the output of the amount detecting means and the rotation speed of the load, and the primary side hydraulic control valve is controlled so that the actual speed ratio matches the target speed ratio. A gear ratio control means, a transmission torque detecting means for detecting a transmission torque of the continuously variable transmission, and a secondary side hydraulic control valve according to an output of the transmission torque detecting means to control the primary side pulley and the secondary side. The clamping force required for the pulley is generated. The gear ratio control means multiplies the deviation between the target gear ratio and the actual gear ratio by a predetermined gain, and divides the value by a variable corresponding to the secondary pressure of the continuously variable transmission. It includes integration control calculation means for integrating and outputting a value obtained by multiplying the integrated value by the above variable.

A shift control device for a continuously variable transmission according to a second aspect of the present invention is the shift control device according to the first aspect, wherein the shift control means comprises:
A feedforward control calculation unit is provided, and the feedforward control amount is determined at least from a predetermined hydraulic pressure ratio.

According to a third aspect of the present invention, there is provided a continuously variable transmission shift control device according to the second aspect, wherein a predetermined hydraulic pressure ratio value is used as a torque ratio and a target speed ratio of the target continuously variable transmission. The value is smaller than the average value of the hydraulic pressure ratio based on the above.

According to a fourth aspect of the present invention, there is provided a continuously variable transmission shift control device according to the first to third aspects, wherein the integral control calculation means integrates a predetermined time after the shift start from the previous maximum gear ratio. The stored value corresponding to the value is used as the initial value of the integrated value at the start of gear shift from the next maximum gear ratio.

[0017]

According to the invention of claim 1, the integral control calculation means integrates a value obtained by multiplying the deviation by a predetermined integral gain and dividing by the secondary side pressure, and outputs a value obtained by multiplying the integrated value by the secondary side pressure. To do. As a result, even under the condition that the driver operates the accelerator, the input torque increases, and the secondary side pressure increases, the primary side pressure P ₁ = P ₂ that immediately causes ΔP _{1 in the} above equation (2) to be 0.
- Since the output of the P _R, the gear ratio is hardly changed.
This is because when the CVT input torque changes, the secondary side pressure is controlled so that the torque ratio is almost constant because the safety factor is constant, and therefore the hydraulic pressure ratio of the above equation (1) is before and after the change. It is constant at.

According to the second aspect of the present invention, the feedforward control amount in the feedforward control computing section of the shift control means is determined from at least a predetermined hydraulic pressure ratio (the ratio of the primary side pressure to the secondary side pressure). As a result, the integrated value is a hydraulic pressure ratio, and the deviation becomes a value before the change of accelerator operation → input torque increase → secondary side pressure increase by the driver. The control calculation is 0, and the primary side pressure, which is the manipulated variable, is determined by the product of the integrated value and the secondary side pressure. Therefore, the same state can be maintained even after the above change.

According to the third aspect of the present invention, the value of the predetermined hydraulic pressure ratio is set to a value smaller than the average value of the torque ratio of the target continuously variable transmission and the hydraulic pressure ratio based on the target speed ratio. Even if the gear ratio feedback control cannot be performed due to a failure of the rotation speed detecting means of the transmission, the gear can be shifted to the lowest speed side where the driving force of the load can be secured, and the system reliability can be improved.

According to another aspect of the present invention, the stored value corresponding to the integrated value at a predetermined time after the start of the shift from the previous maximum gear ratio is set to the initial value of the integrated value at the start of the shift from the next maximum gear ratio. Therefore, the shift delay at the start of the shift control can be improved.

[0021]

EXAMPLES Example 1. Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings, taking a case where it is applied to a belt type continuously variable transmission for a vehicle as an example. FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an engine (engine), the rotation of which is CV via an engine output shaft 2 and a clutch 3.
It is transmitted to T8, after being speed steplessly have you in this CVT8, is adapted to be transmitted via a differential device (not shown) to driving wheels (not shown). The CVT 8 includes a pair of input shaft 4 and an output shaft 9 that are parallel to each other, and a pair of primary-side pulley 5 and secondary-side pulley 7 that are provided on the input shaft 4 and the output shaft 9 and have a variable effective diameter. Drive belt 6 wound between these pulleys 5 and 7
If, respectively provided on the input shaft 4 and the output shaft 9, and a primary-side hydraulic cylinder 5c and secondary side hydraulic cylinder 7c applying thrust in the direction to reduce the V groove width to the variable pulleys 5 and 7 I have it.

The pulleys 5 and 7 are fixed rotating bodies 5a and 7a fixed to the input shaft 4 and the output shaft 9, respectively.
And movable rotary members 5b and 7b which are provided on the input shaft 4 and the output shaft 9 such that they cannot rotate relative to each other and are movable in the axial direction. The pressure receiving area of the primary side hydraulic cylinder 5c is set to be larger than the pressure receiving area of the secondary side hydraulic cylinder 7c, and it functions as a hydraulic actuator that moves the movable rotating bodies 5b and 7b.
By changing the ratio of the radius of wrapping around the secondary pulley 7 and the secondary pulley 7, continuously variable speed is achieved.

Reference numeral 10 denotes a hydraulic pump, which is driven by the engine 1 and sends the hydraulic oil returned to the oil tank 15 through the oil passage 13 to the secondary hydraulic control valve 1.
1, pressure is fed to the primary side hydraulic control valve 12 and the secondary side hydraulic cylinder 7c. The secondary side hydraulic control valve 11 is usually a controller 20 that is configured by a microcomputer.
The hydraulic oil in the oil passage 13 is returned according to the signal S ₂ from the oil passage 1
6 to the secondary side pressure P which is the oil pressure of the oil passage 13.
Adjust pressure ₂ . If the oil pressure in the oil passage 14 is higher than the oil pressure corresponding to the signal S ₁ from the controller 20, the primary-side hydraulic control valve 12 causes the hydraulic oil in the oil passage 14 to flow out into the return oil passage 16 to reduce the pressure, and the signal S if lower than the hydraulic pressure corresponding to _1, by boosting allowed to flow into the hydraulic oil in the oil passage 13 to the oil passage 14, an oil pressure of the oil passage 14 in accordance with signal S ₁ 1 primary side pressure P ₁
Regulate the pressure.

The clutch 3 is, for example, an electromagnetic clutch, which changes its transmission torque from zero to a maximum value in accordance with a signal S _C from the controller 20 to thereby disengage the clutch, bring it into a half-clutch (slip) state, and directly connect it. Works with. The controller 20 is the bus line 2
It includes an input port 20c, an output port 20d, an MPU 20a and a memory 20b which are connected to each other at 0e. Input of throttle opening detector 21 as required load amount detecting means for detecting throttle opening θ of throttle valve 22 in intake pipe 17 of engine 1, engine speed detector 18 for detecting engine speed Ne, and CVT 8. Each detection output of the CVT input shaft rotation speed detector 19 for detecting the rotation speed N ₁ of the shaft 4 and the CVT output shaft rotation speed detector 23 for detecting the rotation speed N ₂ of the output shaft 9 of the CVT 8 are input to the input port 20c. The controller 20 processes these input signals according to a program stored in the memory 20b in advance and supplied to the clutch 3 and the primary side hydraulic control valve 1.
2, to the secondary side hydraulic control valve 11, the respective signals S _C ,
The S _1, S ₂ is output from the output port 20d as the driving signal.

FIG. 2 is a functional block diagram showing an example of a concrete circuit configuration of the controller 20 shown in FIG. In the actual gear ratio calculating means 30, the ratio of the input rotation speed N ₁ from the CVT input shaft rotation speed detector 19 to the output rotation speed N ₂ from the CVT output shaft rotation speed detector 23, that is, CV
The gear ratio R (= N ₁ / N ₂ ) of T8 is calculated. In the first target gear ratio calculation means 31, the throttle opening θ from the throttle opening detector 21 stored in advance as shown in FIG.
And a target primary-side rotation speed is obtained from the relationship between the output rotation speed N ₂ and the output rotation speed N ₂ , and a steady-state gear ratio target value Rb, which is a value divided by the output rotation speed N ₂ at that time, is determined. . A plurality of relationships shown in FIG. 3 are prepared and are selected by a shift position S _R (for example, R, N, D, L, etc.) detected by a shift position detector 24 such as a shift lever (not shown).

In the operation mode determining means 32, the output rotational speed N ₂ corresponding to the vehicle speed and the vehicle acceleration A _{C of the} differential value thereof,
The output of the braking state detector 25, which detects the braking state of the vehicle from the brake signal and the vehicle acceleration A _C, and the throttle opening θ
Or its differential value, the shift position S _R, and the predetermined judgment values corresponding to these pieces of information, the vehicle operating state and the driver's will are estimated, and the target including the transient state is estimated. The operating condition (operating mode Mo) for determining the gear ratio (second target gear ratio) R _S and the secondary side pressure target value is, for example,
It determines which region (mode) of the stop mode, the start mode, the normal traveling mode, the sudden acceleration mode, the sudden deceleration mode, the downhill mode, and the slippery road mode.

In the second target gear ratio calculation means 35, when the first target gear ratio Rb changes, the second target gear ratio Rb is equal to or lower than the maximum speed ratio change speed predetermined from the actual gear ratio R and the operation mode Mo.
A second target gear ratio R _S (hereinafter simply referred to as a target gear ratio) that changes following the first target gear ratio Rb is calculated. In the input torque calculation means 34 as the transmission torque detection means,
The engine output torque T _E is obtained from the relationship between the throttle opening θ and the engine rotation speed Ne as shown in FIG. 3, and the CVT input torque T ₁ is calculated according to the following equation.

T ₁ = T _E -J · dNe / dt (3)

In the equation (3), J is the total moment of inertia between the engine and the primary pulley. In the target secondary side pressure calculating means 37, the target gear ratio R
_{From S} , CVT input torque T ₁ and operation mode Mo,
The target gear ratio R _S without CVT8 belt slipping
The target secondary side pressure P _2S required for gear shift control is determined. In the secondary side current calculation means 38, the drive current I of the secondary side hydraulic control valve 11 is calculated from the current-hydraulic characteristic as shown in FIG.
Calculates and outputs ₂ .

The target primary side pressure calculating means 40 calculates the primary side pressure necessary for shifting the CVT 8, that is, the target primary side pressure P _1S so that the actual gear ratio R matches the target gear ratio R _S. An example of this target primary side pressure calculating means 40 is shown in FIG.
Shown in. In the figure, pulley position calculation units 44 and 45
Converts the target gear ratio R _S and the actual gear ratio R into the target pulley position X _S and the actual pulley position X, respectively. In the following description, the smaller the gear ratio, the larger the value indicating the pulley position.

The feedback control calculation unit 47 as the integral control calculation means has an output pulley position deviation X of the adder 46.
_{For E} , control law calculation such as PID (proportional, integral,
Differential) control calculation is performed and P _1FB for feedback control is output. The torque ratio calculation unit 41 determines a torque ratio T _R defined as the ratio of the input torque T _{1 to} the torque T _MAX (function of the target gear ratio R _S ) that can be transmitted at the target secondary side pressure P _2S without belt slip. In the hydraulic pressure ratio calculation unit 42,
From the torque ratio T _R and the target gear ratio R _S obtained previously, the hydraulic pressure ratio P _R
(Primary side pressure / Secondary side pressure) is determined from the predetermined relationship shown in FIG. Next, the feedforward control calculation unit 43 obtains the feedforward control amount P _1FF from the hydraulic pressure ratio P _R , the target secondary side pressure P _2S and the differential value of the target pulley position X _S = the target pulley moving speed V _PS by the following formula.

P _1FF = P _2S × P _R + K _V × V _PS (4)

In this equation (4), K _V is a predetermined value. With respect to the result of adding the feedback control component P _1FB and the feedforward control component P _1FF in the adder 48, the target primary side pressure limiting unit 49 _sets the target secondary side pressure as its upper limit value, and the input torque T ₁ and the actual speed change. From the ratio R, the lowest hydraulic pressure at which the belt does not slip on the primary side pulley is set as the lower limit value, and the value after being limited to a value between the lower limit value and the upper limit value is output as the target primary side pressure P _1S .

Now returning to FIG. 2, the primary side current control means 3
6, in the same manner as the secondary side current control means 38, the drive current I is determined from the predetermined relationship between the hydraulic pressure and the current as shown in FIG.
₁ is determined and output to the primary hydraulic control valve 12. In addition,
The first target speed ratio calculation means 31, the second target speed ratio calculation means 35, and the operation mode determination means 32 constitute a target speed ratio determination means, and the target primary side pressure calculation means 40 and the primary side current control means 36 change speed. The target secondary side pressure calculation means 37 and the secondary side current control means 38 constitute a ratio control means, and a secondary side pressure control means.

FIG. 7 is a block diagram showing an example of a concrete circuit configuration of the feedback control calculation unit 47. In the figure, K _P , K _D , and K _I are proportional gain, differential gain, and integral gain, respectively, and Z ⁻¹ is an operator used in Z conversion, and the PID control calculation of this feedback control calculation unit 47 is The difference from the normal PID control calculation is the deviation X _E
Is divided by the target secondary side pressure P _2S , multiplied by an integration gain K _I and integrated, and the integrated value P _INT is multiplied by the target secondary side pressure P _2S and output.

Further, in the hydraulic pressure ratio calculation unit 42, a map as shown in FIG. 4 is provided for determining the hydraulic pressure ratio. Means for coping with product variations and changes with time of the value of the hydraulic pressure ratio P _R. As one of the methods, there is a method of setting a map value that allows shifting to the lowest speed side without feedback control even if there is an expected change in the hydraulic pressure ratio characteristic. That is, the map value for determining the oil pressure ratio is set to a small value in the area of the actual oil pressure ratio data corresponding to each point (torque ratio, gear ratio), so that, for example, when the CVT input shaft rotation speed detector malfunctions Even if the ratio feedback control cannot be performed, the gear can be shifted to the lowest speed side where the driving force of the vehicle can be secured, and the reliability of the system can be improved.

However, setting the oil pressure ratio map value to be smaller than the average value of the actual machine characteristics (characteristics such as torque ratio, speed change ratio, oil pressure ratio, etc., which differ depending on the actual product) is controlled under the condition that the deviation of the feedforward amount is large. Therefore, there is a disadvantage in that the control delay is increased particularly when the shift control is started or when the target gear ratio is suddenly changed. FIG. 8 shows the main state variables on the time axis from when the vehicle starts from the stopped state to coast to the sudden stop. In order to improve the shift delay at the start of the shift control described above, the region shown by the learning range in FIG. 8, that is, the target gear ratio is shifted from the lowest speed (R = 2.5 in this example) to the highest speed (R = 0.5 in this example). Since the start, the target gear ratio has a predetermined value smaller than the minimum speed (for example, R =
In the areas up to 2.1), the following controls are implemented.

1) The learning value stored in a predetermined place at the start of the above-mentioned learning is substituted into the integral value P _INT of the feedback control calculation unit 47 (initialization of the integral value). 2) The integral value P _INT is stored as a learning value in a predetermined place at the end of the above learning. 3) The learning value described above is stored in a so-called backup memory area that is stored even when the key of the vehicle is turned off. Here, the integral value can be used for this learning control is
It is obvious that this integrated value is due to the value corresponding to the hydraulic pressure ratio.

Example 2. In the above embodiment, the case where the throttle opening θ is used to detect the required load of the engine has been described, but the present invention is not limited to this. For example, the operation amount of the accelerator pedal, the intake pipe negative of the engine, and the like. It may be an amount such as pressure.

Example 3. Further, the hydraulic pressure ratio may be a final pulley pressing force ratio. Therefore, the present invention is not limited to the belt type continuously variable transmission as long as the transmission can be expressed as the ratio of the pressing force on the primary side to the pressing force on the secondary side.
Other continuously variable transmission, for example, a toroidal type continuously variable transmission may be used.

Example 4. In the learning control described above, learning and storage may be performed separately for each of a plurality of engine load amounts such as the throttle opening.

Example 5. Furthermore, in the above embodiment, the case where the present invention is applied to a continuously variable transmission for a vehicle has been described, but the present invention is not limited to this, and other devices such as a continuously variable transmission for an aircraft or a ship, etc. Can be applied in the same manner and has the same effect.

[0043]

As described above, according to the invention of claim 1, the rotation speed detecting means for detecting the rotation of each of the primary pulley and the secondary pulley of the continuously variable transmission, and this rotation speed detection. An actual speed ratio calculating means for calculating an actual speed ratio from the ratio of the respective rotational speeds from the means, a required load amount detecting means for detecting a load amount required for the engine, and an output and a load of at least the required load amount detecting means. Target speed ratio determining means for sequentially determining the target speed ratio based on the rotation speed of the gear, speed ratio control means for controlling the primary side hydraulic control valve so that the actual speed ratio matches the target speed ratio, Transmission torque detecting means for detecting the transmission torque of the transmission, and the secondary side hydraulic control valve is controlled according to the output of the transmission torque detecting means to generate a clamping force required for the primary side pulley and the secondary side pulley. Equipped with secondary side pressure control means The gear ratio control means integrates a value obtained by multiplying the deviation between the target gear ratio and the actual gear ratio by a predetermined gain, and dividing the value by a variable corresponding to the secondary side pressure of the continuously variable transmission. Since the integral control calculation means for outputting the value multiplied by the variable is included, there is an effect that excellent followability with respect to the target gear ratio can be obtained.

According to a second aspect of the present invention, in the first aspect of the invention, the shift control means has a feedforward control calculation section and determines the feedforward control amount from at least a predetermined hydraulic pressure ratio. The feedforward control amount becomes a function of the hydraulic pressure ratio, and it becomes easy to correct the feedforward control amount by using this integral value, and it is possible to improve the variation in the shift characteristics of the continuously variable transmission. is there.

According to the invention of claim 3, in the invention of claim 2, the value of the predetermined hydraulic ratio is smaller than the average value of the hydraulic ratio based on the torque ratio and the target speed ratio of the target continuously variable transmission. Since the value is set to a value, even if feedback control of the gear ratio cannot be performed due to a failure of the rotation speed detection means of the continuously variable transmission, the gear can be shifted to the lowest speed side that can secure the driving force of the load, and the system reliability can be improved. There is an effect that can improve.

According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the integral control calculation means stores the stored value corresponding to the integral value at a predetermined time after the start of the shift from the previous maximum gear ratio. Since the initial value of the integral value at the time of starting the shift from the next maximum speed ratio is set, there is an effect that the shift delay at the start of the shift control can be improved.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a main part of an embodiment of a shift control device for a continuously variable transmission according to the present invention.

FIG. 3 is a diagram showing a map for determining a target gear ratio of an embodiment of a shift control device for a continuously variable transmission according to the present invention.

FIG. 4 is a diagram showing a map for determining a hydraulic pressure ratio of an embodiment of a shift control device for a continuously variable transmission according to the present invention.

FIG. 5 is a diagram showing a relationship between a control current of a hydraulic control valve and an output hydraulic pressure in an embodiment of a shift control device for a continuously variable transmission according to the present invention.

FIG. 6 is a block diagram showing a main part of an embodiment of a shift control device for a continuously variable transmission according to the present invention.

FIG. 7 is a block diagram showing a main part of an embodiment of a shift control device for a continuously variable transmission according to the present invention.

FIG. 8 is a diagram for explaining the operation of an embodiment of a shift control device for a continuously variable transmission according to the present invention.

[Explanation of symbols]

2 engine output shaft, 4 CVT input shaft, 5 primary pulley, 7 secondary pulley, 8 CVT, 9 CVT output shaft, 10 hydraulic pump, 11 secondary hydraulic control valve, 12
Primary side hydraulic control valve, 18 engine speed detector,
19 CVT input shaft rotation speed detector, 20 controller, 21 throttle opening detector, 22 throttle valve,
23 CVT output shaft rotation speed detector, 24 shift position detector, 25 braking state detector, 30 actual gear ratio calculating means, 31 first target gear ratio calculating means, 32 operating mode determining means, 34 input torque calculating means, 35 Second target gear ratio calculation means, 36 Primary side current control means, 37
Target secondary side pressure calculation means, 38 Secondary side current control means, 4
0 target primary side pressure calculation means, 43 feedforward control calculation part, 47 feedback control calculation part.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI F16H 101: 02 F16H 101: 02 (58) Fields investigated (Int.Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (4)

(57) [Claims] 1. A primary pulley and a secondary pulley having a fixed pulley portion, a movable pulley portion, and a hydraulic servo provided on the movable pulley portion, the effective diameter being continuously variable, and a tension between these pulleys. A secondary side hydraulic control valve that regulates the hydraulic pressure generated by the hydraulic pressure source and supplies it to the hydraulic servo of the above-mentioned secondary side pulley and the installed drive belt and regulates the secondary side pressure to the hydraulic servo of the above-mentioned primary side pulley. With a primary hydraulic control valve to supply,
In a continuously variable transmission that continuously changes the rotation of an engine and transmits it to a load, a rotation speed detecting means for detecting rotations of each of the primary pulley and the secondary pulley, and the rotation speed detecting means. An actual speed ratio calculating means for calculating an actual speed ratio from the ratio of the respective rotational speeds, a required load amount detecting means for detecting a load amount required for the engine, and an output of at least the required load amount detecting means and the load. Target speed ratio determining means for sequentially determining the target speed ratio based on the rotation speed of the engine, and the above-mentioned 1 so that the actual speed ratio matches the target speed ratio.
Gear ratio control means for controlling the secondary side hydraulic control valve, transmission torque detecting means for detecting the transmission torque of the continuously variable transmission, and control of the secondary side hydraulic control valve according to the output of the transmission torque detecting means. The primary pulley and the above 2
The secondary side pressure control means for generating a clamping force required for the secondary side pulley is provided, and the speed ratio control means multiplies a deviation between the target speed ratio and the actual speed ratio by a predetermined gain to provide the stepless speed control. Gearbox 2
A shift control device for a continuously variable transmission, comprising: integral control calculation means for integrating a value divided by a variable corresponding to the secondary side pressure and outputting a value obtained by multiplying the integrated value by the variable. 2. The shift control device for a continuously variable transmission according to claim 1, wherein the shift control means has a feedforward control calculation unit, and determines the feedforward control amount from at least a predetermined hydraulic pressure ratio. 3. The continuously variable transmission according to claim 2, wherein the value of the predetermined hydraulic pressure ratio is smaller than the average value of the torque ratio of the target continuously variable transmission and the hydraulic pressure ratio based on the target speed ratio. Shift control device. 4. The integral control calculation means stores a stored value corresponding to an integrated value at a predetermined time after the start of a shift from the previous maximum speed ratio as a value of the integrated value at the start of a shift from the next maximum speed ratio. The shift control device for a continuously variable transmission according to claim 1, wherein the shift control device has an initial value.