JPH0413578B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a hydraulic control device for a belt-driven continuously variable transmission for a vehicle.

Prior Art The present applicant previously filed Japanese Patent Application No. 57-40747 (Japanese Unexamined Patent Publication No. 58
-16066) etc., continuously variable transmissions (hereinafter referred to as CVT)
disclosed a vehicle power transmission device that utilizes the following. A CVT in such a device includes an input side disk and an output side disk with variable effective diameters provided on the input shaft and output shaft, and a belt wound around the input side disk and the output side disk. Determine a control pressure for controlling the tension of the belt based on a first variable from a first relationship obtained theoretically, and set the control pressure to:
It is made to act on one of the hydraulic servos that change the effective diameters of the input side disk and the output side disk.

On the other hand, the present applicant previously filed a patent application filed in 1983-
No. 96122 (Japanese Unexamined Patent Publication No. 58-214054) proposed a hydraulic control device that can control the control pressure to a value almost immediately before the belt begins to slip. According to this, there is provided a means for controlling the control pressure based on the actually obtained state variable by using a change characteristic related to the slippage of the belt in the second relationship between the control pressure and the state variable. As a result, the control pressure is controlled to a necessary and sufficient value regardless of oil temperature, belt wear status, rotation speed, etc., increasing the durability of the CVT and increasing the power required to drive the oil pump. Losses are reduced.

Problems to be Solved by the Invention By the way, in the above-mentioned type of hydraulic control device, depending on the operating state of the vehicle, it is difficult to obtain reliability in the state variable representing the power transmission state in relation to the power transmission state of the CVT. In some cases, there was a problem that the control accuracy of the control pressure was sometimes impaired. For example, when the engine rotates at high speed, it becomes difficult to detect the pulsation of the input shaft torque T _io . However, if the state variable is derived from the pulsation of the input shaft torque T _io of the CVT, This makes it difficult to obtain reliability of state variables.

The present invention was made against the background of the above-mentioned circumstances, and its purpose is to control the oil temperature even in a region where reliability of state variables cannot be obtained when controlling the control pressure related to belt slippage. Another object of the present invention is to provide a hydraulic control device that can control the control pressure as necessary and sufficiently regardless of the state of wear of the belt, the rotational speed, etc.

Means for Solving the Problems The gist of the present invention to achieve the above object is to provide an input side disk and an output side disk with variable effective diameters provided on an input shaft and an output shaft, and these input side disks. In a belt-driven continuously variable transmission having a belt wound around an output side disk, one of the hydraulic servos that changes the effective diameter of the input side disk and the output side disk in order to control the tension of the belt. A pressure regulating valve that regulates the control pressure to be applied, and a control value determining means that determines a control value for driving the pressure regulating valve based on an actual input torque and a gear ratio from a pre-stored relationship. A hydraulic control device for a belt-driven continuously variable transmission, comprising: (a) changing in accordance with occurrence of belt slippage of the continuously variable transmission;
(b) a state variable calculation means for calculating a state variable related to a power transmission state of the continuously variable transmission; and (b) feedback correction based on the state variable so that the control value becomes a value immediately before belt slippage occurs. (c) feedback correction means for determining the control value and correcting the control value based on the feedback correction value; (d) determining whether the state variable calculated by the state variable calculating means is in an operating region in which reliability can be obtained or in an operating region in which reliability cannot be obtained; , if the state variable is in a region where the reliability of the state variable can be obtained, correction of the control value by the feedback correction means is allowed; if the state variable is in a region where the reliability cannot be obtained, correction of the control value by the feedback correction means is blocked. and a determination means for determining.

Operation and Effect of the Invention By doing this, by the relationship modification means,
While the pre-stored relationship based on the corrected control value and the input torque and gear ratio at that time is corrected by the feedback correction means, the judgment means determines that the state variable is not in an operating range where reliability can be obtained. If it is determined that the control value is corrected by the feedback correction means,
The control pressure is controlled using the control value obtained from the above-mentioned corrected relationship. Therefore, even in areas where the reliability of state variables cannot be obtained, the control pressure is necessary and sufficiently controlled regardless of oil temperature, belt wear status, rotation speed, etc., increasing the durability of CVT. At the same time, power loss for driving the oil pump is suppressed.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

FIG. 1 shows a continuously variable transmission type vehicle power transmission device. In the figure, a crankshaft 2 of an engine 1 is connected to an input shaft 5 of a CVT 4 via a clutch 3. In CVT4, a pair of input side disks 6,
7 are arranged to face each other, one input side disk 6 is supported by the input shaft 5 so as to be movable in the axial direction, and the other input side disk 7 is fixed to the input shaft 7. A pair of output side disks 8 and 9 are also arranged opposite to each other, one output side disk 8 is fixed to the output shaft, and the other output side disk 9 is supported by the output shaft 10 so as to be movable in the axial direction. There is. 1
The opposing surfaces of the pair of input side disks 6, 7 and output side disks 8, 9 are formed such that the distance between them increases as they move radially outward. The belt 11 is an endless belt with a trapezoidal cross section, between the input side disks 6 and 7 and the output side disks 8 and 9.
It is wrapped between. Pressure regulation (relief)
The valve 15 connects the oil pan 16 to the oil pump 17.
The pressure of the oil sent through the oil passage 18 is regulated to generate line pressure Pl in the oil passage 19. This line pressure Pl is a control pressure for controlling the tension of the belt 11.

In order to adjust the line pressure, the flow rate of oil returned to the drain oil passage 20 is controlled, and the oil passage 19 is connected to the hydraulic servo of the output side disk 9. The flow rate control valve 24 is connected to the oil passage 19, the drain oil passage 25, and the oil passage 26, and the oil passage 26 is connected to the hydraulic servo of the input side disk 6. When increasing the servo oil pressure of the input side disc 6, the oil passage 26 is connected to the oil passage 19 in the flow control valve 24, and when decreasing the servo oil pressure of the input side disc 6, the oil passage 26 is connected to the oil passage 19. Connect to 25. Torque sensors 29 and 30 detect the torque of input shaft 5 and output shaft 10, respectively, from changes in the direction of the magnetic field. Rotation angle sensors 31 and 32 detect the rotation speeds of input side disk 7 and output side disk 8, respectively. Throttle actuator 35
The accelerator pedal sensor 36 controls the opening degree of the intake system throttle valve, and the accelerator pedal sensor 36 controls the accelerator pedal 3 near the driver's seat 37.
The amount of depression of 8 is detected.

As the servo oil pressure of the output side disk 9 increases, the output side disk 9 is pressed toward the output side disk 8, and accordingly, the contact position of the belt 11 on the disks 8 and 9 is moved radially outward. It will be done. The line pressure Pl is controlled so that the belt 11 does not slip against the disks 8 and 9. Furthermore, as the servo oil pressure of the input side disk 6 increases, the input side disk 6 is pressed toward the input side disk 7, and as a result, the contact position of the belt 11 on the disks 6 and 7 moves outward in the radial direction. The speed ratio e of the CVT 4 is thereby controlled. The servo oil pressure of the input side disk 6 ≦ the servo oil pressure of the output side disk 9, but the pressure receiving area of the hydraulic servo of the input side disk 6 ≧ the output side disk 9
Since the pressure receiving area of the hydraulic servo is , a speed ratio of 1 or more can be realized.

In this embodiment, the required horsepower is set as a function of the amount of depression of the accelerator pedal 38, and the target torque and target rotational speed of the engine 1 are set as functions of the required horsepower. The opening degree of the intake system throttle valve is controlled as a function of the target torque, and the speed ratio e of the CVT 4 is controlled as a function of the target rotational speed. The control of the output torque and rotational speed of the above engine is described in Japanese Patent Application Laid-open No. 58-
It is similar to that described in Publication No. 16066. To explain in more detail, the amount of accelerator pedal operation
The target driving _force PS' is determined based on the actual accelerator pedal operation amount X _acc from a pre-stored relationship between X acc and the target driving force PS', and the target driving force
Based on the above target driving force PS', from the pre-stored relationship between PS' and the target engine rotational speed N _io ' and the relationship between the target driving force PS' and the target output torque T _e ' of the engine. target engine speed
N _io ′ and target output torque T _e ′ are respectively determined, and the target engine rotation speed N _io ′ and target output torque T _e ′ are the actual engine rotation speed N _io
and CVT4 to match the output torque T _e
The speed ratio e and the throttle valve opening are each controlled by feedback.

In this embodiment, it is determined whether the control region of the line pressure Pl is the optimum line pressure control implementation region A or the optimal line pressure control non-implementation region B from the pre-stored relationship shown in FIG. Region A is the input side rotational speed N _io of CVT4
(=engine rotational speed N _e ) and input side torque T _io (=engine output torque T _e ) are both defined as a reliable interval. That is, in this embodiment, the area A is a state variable calculated by step S63, which will be described later, which functions as a state variable calculating means (=effective value A _put of pulsation component T _put ^* /pulsation component T _io ^* effective value A _io ), and the phase difference θ nax , θ between the pulsating component T _io * of the input torque T _io and the pulsating component T _io ^* of the output torque T _put , ^which are state variables calculated in step S117 described _below . _nio
This is an operating region in which sufficient reliability can be obtained in the amplitude _Aput of the pulsation component _Tio ^* , which is a state variable calculated in step S131, which will be described later. On the other hand, region B is a region in which the state variables described above are not reliable and the effect of correction by the feedback correction value cannot be expected. In addition, N _ionax in Figure 2
is a value that makes it difficult to detect the pulsation components T _io ^* and T _put ^* when engine 1 is in a higher rotation range, and N _ionio in Figure 2 is a value when engine 1 is in a lower rotation range below this value. This is a value at which the clutch 3 becomes half-engaged or disengaged, making it difficult to detect the pulsating components T _io ^* and T _put ^* . Also, T _ionio and
T _ionax is a value that, if the line pressure falls below or above, a problem will occur in line pressure control in relation to the characteristics of the pressure regulating valve 15.

FIG. 3 is a flowchart showing an example of the optimal line pressure control algorithm of this embodiment. In step 51, the first intended value K _p ^* of K ^* is read. In step 52, K _p ^* is assigned to K ^* .
K ^* = K _p ^* only once at the beginning, and thereafter K ^* is determined in the optimum line pressure control routine at step 56, more specifically at step 71 in FIG.

Next, step 5 corresponding to the control value determining means
In step 3, the basic value V _put ^* of the voltage to be sent to the amplifier 92 for the pressure regulating valve 15 is calculated based on the actual input shaft torque T _io and speed ratio e from the following formula stored in advance. This V _put ^* is expressed by the following formula.

V _put ^* = K ^*・T _put = K ^*・T _io /e = K ^*・f (e, T _io ) However, T _put : CVT4 output shaft torque (does not include vibration component) T _io : CVT4 (not including vibration components) e: Speed ratio of CVT 4 = Output side rotation speed of CVT 4 N _put /Input side rotation speed of CVT 4 N _io f: Function In step 54, the amplifier 92 for the pressure regulating valve 15 is
The voltage sent to the line pressure control value _Vput is set to the actual value K· _Vput ^* . However, K is a constant larger than 1, and by setting V _put > V _put ^* , the line pressure Pl is set to a value slightly larger than an appropriate value (theoretical value), and slippage of the belt 11 is reliably prevented. The relational expressions used in the above steps 53 and 54 are stored in advance, and the control value _Vput obtained from the relational expressions remains unchanged without being corrected when the judgment in the next step 55 is negative. is used for line pressure control. Note that as V _put increases, the amount of drain in the pressure regulating valve 15 decreases, and the line pressure Pl is expressed by the following equation.

Pl=K ₁ ·V _put +K ₂ However, K ₁ and K ₂ are constants.

In step 55, CVT is activated by N _io and T _io .
4 is within the A range indicated by the pre-stored relationship shown in FIG. The process returns to S53. That is, in this embodiment, the step S55 is an operating region A in which reliability of the state variable, that is, the amplitude ratio r of the vibration component calculated in step S63 in FIG. If it is the area A that can be obtained, the feedback correction is allowed in the execution of the optimum line pressure control routine in step S56, and if it is the area B that cannot be obtained, the feedback correction is blocked, and steps 53 and Line pressure control is executed with the control value V _put determined in step 54 unchanged. Therefore, in step 55, it is determined whether the state variable is in the reliable region A or the unreliable region B, and if it is in the region B, the feedback correction is blocked and the line pressure Pl is changed. It functions as a determining means for executing open loop control. The details of the optimum line pressure control in step S56 will be explained with reference to FIG.

In the optimum line pressure control routine shown in FIG. 4, in step 60, the input torque T _io and the output torque T _put are read. In the following step 61, the input side torque T _io and the output side torque
Frequency fluctuation components T _io ^* and T _put ^* , respectively included in T _put and corresponding to the explosion period in the engine 1, are extracted by the frequency discrimination function of the bandpass filter on the software. In step 62, effective values A _io and A _put of the fluctuation components T _io ^* and T _put ^* are calculated. In step S63 in FIG. 4, which functions as state variable calculating means, the amplitude ratio (state variable) r (=A _put /A _io ) of the pulsating component is calculated. Next, in step 64, α=[r(k)/r(k
-1)] -a is calculated. However, r(k) is r, r(k
-1), r and a obtained by the previous execution of step 63 are constants.

In step 65, the above α and 0 are compared,
If α≧0, step 70 is executed and the current correction amount V _fb (k) is obtained by subtracting the predetermined change value ΔV from the previous correction amount V _fb (k-1), but α<0 If so, step 71 is executed and
After K ^* = V _put /f (T _io , e) is calculated, in step S72, a predetermined change value ΔV is added to the previous correction amount V _fb (k-1) to determine the current correction amount V _fb (k). In step S73, the control value V _put is corrected by adding the feedback correction value V _fb (k) to the basic control value obtained in step 54 as described above. Then, in step 74, it is determined whether or not the vehicle is accelerating or decelerating. If the vehicle is accelerating or decelerating, steps 53 and subsequent steps in FIG. 3 are executed again, but if the vehicle is in a steady state, this routine is executed. Steps 60 and below are executed again.

Figure 5 shows the relationship between line pressure Pl (=output side servo oil pressure of CVT4) and amplitude ratio A _put /A _io . When line pressure Pl becomes smaller than Pl ₁ , amplitude ratio A _put /A _io decreases rapidly and slip occurs from Pl≦Pl ₂ . Therefore, by operating the optimum line pressure control routine described above, if α≧0, Pl>Pl ₁
If α<0, it is determined that Pl<Pl ₁ , and the line pressure Pl is increased by a predetermined amount, and the line pressure Pl is finally Pl ₁ It will be nearby.

In this way, steps 70, 72, and 73 utilize the change characteristics related to the slippage of the belt 11 shown in FIG. 5 to actually adjust the line pressure to the value Pl1 immediately before the slippage of the belt 11 occurs. The feedback correction value V _fb (k) is calculated based on the amplitude ratio r of the feedback correction value V _fb (k).
This corresponds to a feedback correction means that corrects the control value V _put based on.

Furthermore, when the line pressure Pl reaches the value Pl ₁ just before the slippage of the belt 11 occurs by executing the above-mentioned optimum line pressure control routine, in other words, α becomes negative and the line pressure Pl becomes When the belt 11 slips if it is not increased, K ^* when Pl≈Pl ₁ is calculated in step 71. This K ^* is then T _put ^*
This is a coefficient for determining the relationship between V put * and V _put ^* .
Therefore, in step S71 of the optimum line pressure control routine, when the line pressure Pl ₁ reaches the value Pl immediately before the belt 11 slips, the above K ^*
By re-determining , it functions as a relationship modification means for modifying the relationship between T _io /e and V _put ^* used in step 53. Note that K ^* is area B
The line pressure Pl at and the line pressure Pl as the expected value are controlled to appropriate values that are not too large.

FIG. 6 is a functional block diagram of this embodiment.
The hand path filter 78 has an input side torque T _io ,
Fluctuation components included in the output side torque T _put , that is, explosion frequency components T _io ^* and T _put ^* are extracted. The explosion frequency is detected from N _io . Block 79 corresponds to step 62, and the effective values of T _io ^* and T _put ^* are A _io ,
Calculate A _put . Blocks 80 and 82 correspond to steps 63 and 64, respectively, and calculate r and α. Block 82 corresponds to steps 70 and 72, and in relation to α≧0 and α<0, ΔV or −ΔV
Select. Block 83 corresponds to step 73 and corrects V _fb . Block 88 is step 7
1, and when Pl is sufficiently close to the limit value Pl ₁ , K ^*
= _Vput /f( _Tio , e) is calculated. block 90
corresponds to steps 53 and 54, and calculates V _put . Addition point 91 assigns V _put +V _fb to V _put . In region B, addition from block 88 at summing point 91 is stopped, and addition from block 90 is stopped.
V _put is sent as is to the control amplifier 92. The thus calculated V _put is sent to the pressure regulating valve control amplifier 92, and the line pressure Pl ₁ is controlled.

FIG. 7 is a block diagram showing the configuration of the electronic control device. CPU100, RAM101,
ROM102, I/F (interface) 10
3. A/D converter 104, D/A converter 105
are connected to each other by a data bus line 106. Output pulses from the input side rotation angle sensor 31 and the output side rotation angle sensor 32 are sent to the I/F 103. The analog outputs of the input side torque sensor 29 and the output side torque sensor 30 are sent to the integrator 108 via the bandpass filter 78, and A _io ,
A _put is A/D converted by an A/D converter 104 .
The analog output of the input side torque sensor 29 is sent to a low-pass filter 109, and the DC component _{Tio of} Tio is A/D converted by an A/D converter 104. The DC component T _io is used when detecting V _put ^* in step 53 of FIG. The center frequency of the bandpass filter 78 is tuned to the detonation frequency, and the detonation frequency is
Detected from N _io . Output of D/A converter 105
V _put is sent to the pressure regulating valve control amplifier 92 and the line pressure
Pl ₁ is controlled. CPU100 is RAM101
While using the temporary memory function of
2 and processes the input signal according to the program shown in FIGS. 3 and 4 stored in FIG _.
supply.

According to this embodiment, during line pressure control by optimum line pressure control, in step S71 corresponding to the relationship correction means, the line pressure Pl ₁ immediately before the belt 11 slips and the first variable (T _io , e), the pre-stored relationship [V _put ^{* =} K ^* ·f(T _io , e)] is corrected, while step S55 corresponding to the determination means
If it is determined that the state variable (amplitude ratio r of the vibration component) calculated in step S63, which functions as a state variable calculation means, is not in the operating region A in which reliability can be obtained, the feedback correction value V _fb
(k) prevents the correction and performs open-loop control of the control pressure based on the modified relationship. Therefore, even in region B where the reliability of the state variables is not obtained and the control accuracy of the optimum line pressure control routine in step S56 is not obtained, the line pressure Pl is necessary and sufficiently controlled.

Next, another embodiment of the present invention will be described. In addition,
In the following description, only differences from the previous embodiment will be explained, and common parts will be given the same reference numerals and explanations will be omitted.

FIG. 8 shows another principle for detecting belt slip points. Explosive frequency components of T _io and T _put T _io
^* and T _put ^* , if the line pressure Pl is sufficiently high, a maintains a constant phase difference, but if the belt 11 starts to slip, the phase difference changes by more than plus or minus 180° in b. Therefore, the slip point of the belt 11 can be detected by detecting the phase difference between T _io ^* and T _put ^* . Algorithms, functional block diagrams, and modified portions of the electronic control device block diagram of an embodiment utilizing this principle are shown in FIGS. 9, 10, and 11, respectively.

In step 114 in FIG. 9, i=1. In step 115, the phase difference θ between T _io ^* and T _put ^* , that is, the state variable corresponding to the power transmission state of the CVT 4 is detected. Step 116
Then, the variable i and the predetermined value M are compared, and if i=M, i+1 is assigned to i in step 117, and then step 60 is executed. In this way, the phase difference θ is sampled for a predetermined period. However, when i=M, step 118 is executed and the maximum value θ _nax and minimum value θ _nio of θ are calculated. Next, in step 119, a-
(θ _nax −θ _nio ) is assigned to α. When the belt 11 approaches the slipping point, θ _nax −θ _nio increases and α<0.
Furthermore, when the line pressure Pl is sufficiently high, θ _nax −θ _nio is small and α≧0.

In FIG. 10, in the phase difference detection circuit 121, θ
is detected, and in block 122, θ is detected M times and stored. In block 123, θ _nax and θ _nio are detected from the M number of θ. In block 124 α=
Calculate a-(θ _nax −θ _nio ).

In FIG. 11, a phase difference detection circuit 121 is provided between the bandpass filter 78 and the A/D converter 104.

FIG. 12 shows another principle for detecting the slip point of the belt 11 of this embodiment. As the line pressure Pl decreases, the _Tput fluctuation component causes resonance at a certain frequency. As shown in FIG. 12, the amplitude ratio of the resonance component T _put ^* reaches its peak value just before slipping. Therefore, by detecting the resonance component T _put ^* , the slip point of the belt 11 can be detected. Changes to the algorithm using T _put ^* , the functional block diagram, and the block diagram of the electronic control unit are shown in FIGS. 13, 14, and 15, respectively.

In FIG. 13, _Tput is read in step 129. At step 130, a bandpass filter extracts the resonance frequency component _Tput ^* of _Tput . In step 131, the amplitude A _put of T _put ^* is calculated. In step 132, α=A _put (k)
−A _put (k−1)−α is calculated. In this embodiment, A _put (k) corresponds to a state variable representing the power transmission state of the CVT 4 .

In the functional block diagram of FIG. 14, T _put ^* is extracted by the bandpass filter 135, and
36, A _put is calculated, and in block 137, α=
A _put (k)−A _put (k−1)−α is calculated.

In the block diagram of FIG. 15, the output of the output side torque sensor 30 is sent to the A/D converter 104 via a bandpass filter 135 and an integrator 136, and the center frequency of the bandpass filter 135 is set to the above-mentioned resonance. set to the frequency.

FIG. 16 shows a belt 11 according to another embodiment of the present invention.
Another principle for detecting the slip point of is shown. As shown in the figure, the transmission efficiency η (=output/
input) reaches its peak value just before slipping as the line pressure Pl decreases. 17, 18, and 19 show an algorithm utilizing this principle, a functional block diagram, and a modified portion of the block diagram of the electronic control unit.

In the flowchart of FIG. 17, step S14
At 0, T _io , T _put , N _io , N _put are read. In step 141, DC components T _{io and} T _put are extracted by a low- _pass filter.
In step 142, the transfer efficiency η=T _put・N _put /
T _io・N _io is calculated. In step S143,
α=η(k)−η(k−1)−a is calculated. In this embodiment, the transmission efficiency η corresponds to a state variable representing the power transmission state of the CVT 4.

In the functional block diagram of FIG. 18, DC components Tio _{and Tput} are extracted by a low-pass filter 146. In block 147, the transmission efficiency η is calculated, and in block 148, α is calculated.

In the block diagram of FIG. 19, a low pass filter 146 is provided between the torque sensors 29, 30 and the A/D converter 104.

FIG. 20 shows a belt 11 according to another embodiment of the present invention.
Another principle of detecting the slip point of is shown. In the figure, the relationship between the input side servo oil pressure P _io and the output side servo oil pressure P _put of the CVT4 appears as shown by the solid line in Fig. 20 with respect to the line P _io = Sr・P _put , and P _io
The belt 11 slips near the line P _io =Sr·P _put . Sr is expressed by the following formula. In this embodiment, the above P _io and P _put correspond to state variables representing the power transmission state of the CVT 4.

Sr = (A _put・φ _io ) / (A _io・φ _put ) However, A _io : Pressure receiving area of CVT input side servo A _put : Pressure receiving area of CVT input side servo φ _io : Belt winding of input side disk Added angle φ _put : Belt wrapping angle of output side disk Figures 21, 22, and 23 show an algorithm, a functional block diagram, and a block diagram of an electronic control unit of an embodiment that utilizes this principle. ing.

In the flowchart of FIG. 21, step 153
P _io and P _put are read in. Step 15
4, the DC components P _{io *} ^and P _put ^* of P io and P _put are read by the low-pass filter. Step 155
Then, α=P _io −Sr·P _put −a is calculated.

In the functional block diagram of FIG. 22, the low-pass filter 158 removes the direct current components of P _io and P _put , P _io ^* ,
P _put ^* is extracted and α is calculated in block 159.

In the block diagram of FIG. 23, the outputs of the input side oil pressure sensor 162, the output side oil pressure sensor 163, and the input side torque sensor 29
58 to the A/D converter 104.
_Tio is used in step 53 of FIG.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a continuously variable transmission type vehicle power transmission device according to an embodiment of the present invention, FIG. 2 is a diagram showing an implementation area and a non-implementation area of optimal line pressure control in the embodiment of FIG. 1, 3 is a flowchart illustrating the operation of the control device of FIG. 7, and FIG. 4 is a flowchart illustrating the operation of the optimum line pressure control of FIG. 3. FIG. 5 is a diagram for explaining the control principle of the embodiment shown in FIG. FIG. 6 is a functional block diagram of the embodiment of FIG. 7. FIG. 7 is a block diagram illustrating the configuration of an electronic control device provided in the power transmission device of FIG. 1. FIG. 8 is a diagram illustrating the control principle of another embodiment of the present invention, in which a
b indicates a state in which belt slippage has not occurred, and b indicates a state in which belt slippage has occurred. Figure 9, 1st
Figure 0 and Figure 11 are the third example in the embodiment of Figure 8.
FIG. 7 is a modified partial view corresponding to FIGS. 6 and 7, respectively. FIG. 12 is a diagram illustrating the control principle of another embodiment of the present invention. Figures 13 and 14
Figure 15 shows the third example in the embodiment of Figure 12.
FIG. 7 is a modified partial view corresponding to FIGS. 6 and 7, respectively. FIG. 16 is a diagram illustrating the control principle of another embodiment of the present invention. Figures 17 and 18
Figure 19 shows the third example in the embodiment of Figure 16.
FIG. 7 is a modified partial view corresponding to FIGS. 6 and 7, respectively. FIG. 20 is a diagram illustrating the control principle of another embodiment of the present invention. Figures 21 and 22
Figure 23 shows the third example in the embodiment shown in Figure 20.
FIG. 7 is a modified partial view corresponding to FIGS. 6 and 7, respectively. 4...CVT, 6, 7...Input side disk, 8,
9... Output side disk, 11... Belt, 15...
...Pressure regulating valve, block 90, step 53...control value determining means, step 55...determining means, blocks 80, 123, 136, 147, 158...state variable calculating means, steps 63, 115, 13
1, 142, 154...state variable calculation means, block 88, step 71...relationship correction means, blocks 82, 83...feedback correction means, steps 70, 72, 73...feedback correction means.

Claims (1)

[Claims] 1. A belt-driven type having an input-side disk and an output-side disk with variable effective diameters provided on the input shaft and the output shaft, and a belt wrapped around the input-side disk and the output-side disk. In the continuously variable transmission, a pressure regulating valve that regulates a control pressure applied to one of the hydraulic servos that changes the effective diameter of the input side disk and the output side disk in order to control the tension of the belt, and a pre-stored relationship. and control value determining means for determining a control value for driving the pressure regulating valve based on the actual input torque and gear ratio from the above. a state variable calculating means for calculating a state variable related to a power transmission state of the continuously variable transmission that changes with occurrence of slippage of the belt of the continuously variable transmission; a feedback correction means for determining a feedback correction value so as to have a value immediately before the slippage occurs, and correcting the control value based on the feedback correction value; and a control value corrected by the feedback correction means and at that time. relationship modification means for modifying the pre-stored relationship based on the input torque and gear ratio; and whether or not reliability of the state variables calculated by the state variable calculation means is obtained. It is determined whether the control value is in the operating region, and if it is a region in which reliability of the state variable can be obtained, correction of the control value by the feedback correction means is permitted, and if it is a region in which reliability of the state variable is not obtained, the feedback correction is performed. 1. A hydraulic control device for a belt-driven continuously variable transmission, comprising: a determining means for preventing correction of a control value by the means.