JPH08210451A - Line pressure control device for v belt type continuously variable transmission - Google Patents

Abstract

PURPOSE: To properly control a line pressure of a V belt type continuously variable transmission so as to prevent generating a response delay of a downshift speed change according to restepping in. CONSTITUTION: In a controller 17, a target input number of revolutions Ni is obtained from input information, to correspondingly operate a valve 21 through a link 22 by a step motor 23. The valve 21 governs a control pressure Ps to make transmitting ratio between pulleys 1, 2 continuously variable change to ratio corresponding to the target input number of revolutions Ni . In the case of controlling a line pressure PL which is the original pressure, in the controller 17, when displayed increasing a throttle opening TVO such as generating a response delay of a downshift speed change according to restepping in an accelerator pedal, during a preset time corresponding to this response dely, the line pressure PL is made to rise from an ordinary value corresponding to transmission input torque to a line pressure value, higher than this ordinary value, when restepped in the pedal, thus to eliminate the speed change response delay.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention appropriately controls a line pressure, which is important for shift control of a V-belt type continuously variable transmission, and in particular, eliminates a response delay in downshift shift due to re-depression of an accelerator pedal. The present invention relates to a line pressure control device for controlling.

[0002]

2. Description of the Related Art A V-belt type continuously variable transmission is disclosed in, for example, Japanese Patent Application Laid-Open No. 61-105347, wherein one of a pair of pulleys around which a V-belt is wound (usually a secondary pulley). The line pressure is applied to the movable flange, and the shift control pressure obtained by reducing the line pressure by the shift control valve is applied to the movable flange of the other pulley (usually the primary pulley). It is usual that the speed change ratio is controlled steplessly by adjusting the pressure difference between the speed change ratio and the speed change control pressure to a value corresponding to the required speed change ratio.

As is clear from the above description, the line pressure is involved in the tension of the V-belt that is stretched between the pulleys, and increasing the line pressure more than necessary makes the tension of the V-belt excessive. If the line pressure is low and the tension of the V-belt is too low, not only will the transmission efficiency be reduced due to slippage, but also in this case the V-belt will wear out and become durable. Sex is lowered.

Therefore, in general, when the line pressure is created by reducing the pump pressure, for example, JP-A-2-62464 is used.
As described in the publication, it is conventional to control each gear ratio to a minimum value according to the input torque. Even if the line pressure is high or low from the value controlled in this way, V
It adversely affects the durability of the belt.

[0005]

However, in the conventional line pressure control device for the V-belt type continuously variable transmission represented by the one described in the above-mentioned document, the accelerator pedal is almost released when the vehicle is accelerated. Even when the user re-depresses from the above position, the normal line pressure control is performed as it is, and the line pressure control for the re-depression is not particularly performed. Therefore, the following problems occur.

That is, while the accelerator pedal is in a state close to release, the V-belt type continuously variable transmission is set to the gear ratio on the highest speed side in response to the low load demand state of the engine (motor). The line pressure is set to a value close to the minimum value by the above control in response to the transmission input torque being extremely small. Here, when the prime mover is changed from the low load demand state to the high load demand state by re-depressing the accelerator pedal, the continuously variable transmission shifts downshifts toward the low speed side gear ratio in response to the high load demand state.

By the way, the re-depression of the accelerator pedal means that the driver requires a relatively quick acceleration of the vehicle, and the downshift gear shift corresponding to this needs to be quick. Therefore, in the downshift shift at the time of re-depressing, although the line pressure is increased to the torque corresponding value due to the torque increase due to the re-depressing, the response delay is not eliminated only by this, and the response delay of the downshift shift is caused. , It was confirmed that it would be larger than the driver thought.

It is an object of the present invention to raise the line pressure to a value higher than the normal value corresponding to the transmission input torque when the accelerator pedal is depressed again, thereby eliminating the above problem.

[0009]

For this purpose, a line pressure control device for a V-belt type continuously variable transmission according to the first invention is provided with a V
Of the pair of pulleys around which the belt is wound, the line pressure is applied to the movable flange of one pulley, and the gear shift control pressure obtained by reducing the line pressure is applied to the movable flange of the other pulley. In the V-belt type continuously variable transmission in which the speed change ratio is controlled steplessly by the differential pressure between the shift control pressure and the line pressure, the prime mover in front of the continuously variable transmission is re-depressed by the accelerator pedal. A re-depressing detection means for detecting a change from a low load demand state to a high load demand state, and when the re-depression is detected by the means, the line pressure is re-set higher than a normal value corresponding to the transmission input torque. Re-depressing line pressure increasing means for increasing the depressing line pressure value.

In the second aspect of the present invention, the re-depression line pressure increase means performs the re-depression line pressure increase control only when the selection range of the continuously variable transmission is a forward traveling range that does not require engine braking. It is characterized by being configured to execute.

In the third aspect of the invention, the re-depression line pressure increase control is performed only when the actual speed ratio of the continuously variable transmission is a high speed side speed ratio lower than the set speed ratio. It is characterized in that it is configured to execute.

In the fourth aspect of the present invention, the re-depression detecting means re-depresses when the prime mover is changed from a low load demand state to a high load demand state when the throttle opening of the prime mover is increased from less than a minute set value. It is characterized in that it is configured to be.

In the fifth aspect of the present invention, the re-depression detecting means is configured to perform re-depression when the prime mover is changed from a low load demand state to a high load demand state when the throttle opening of the prime mover increases more than a set amount. It is characterized in that it is configured to exist.

In the sixth aspect of the present invention, a time counting means for measuring the elapsed time after the re-depressing is added, and the re-depressing line pressure increasing means responds to the elapsed time measured by the time measuring means, and after the re-depressing. It is characterized in that the above-mentioned re-depression line pressure increase control is executed until the elapsed time of is reached to the set time.

In the seventh invention, the set time is
It is characterized in that it is determined in correspondence with the response delay time of the downshift gearshift due to the re-depression.

[0016]

In the first invention, the V-belt type continuously variable transmission is
Power is transferred between a pair of pulleys via a belt.
At this time, the line pressure is applied to the movable flange of one of the pair of pulleys, and the shift control pressure obtained by reducing the line pressure by the shift control valve is applied to the movable flange of the other pulley. As a result, the V-belt type continuously variable transmission can continuously achieve a speed ratio corresponding to the differential pressure between the shift control pressure and the line pressure. Therefore, an arbitrary gear ratio can be obtained by determining the gear shift control pressure by the above gear shift control valve.

Here, when the re-depressing detecting means detects the switching from the low load request state of the prime mover to the high load request state due to the re-depression of the accelerator pedal, the re-depressing line pressure increasing means changes the line pressure to Raise the line pressure value during re-depression higher than the normal value corresponding to the transmission input torque.

According to the line pressure increase control at the time of re-depressing, the response delay of the downshift gear shift caused by the re-depressing can be eliminated by the increase of the line pressure, and in the conventional V-belt type continuously variable transmission. It is possible to solve the problem that has occurred, that is, the conventional problem that the driver feels uncomfortable due to a large response delay in downshifting when re-depressing.

In the second aspect of the invention, the re-depressing line pressure increasing means is provided only when the selected range of the continuously variable transmission is the forward traveling range that does not require engine braking.
The above-mentioned line pressure increase control at the time of re-depressing is executed.

Forward driving range for engine braking,
In the reverse drive range, the response delay of the downshift is not a problem, and only when the forward drive range does not require engine braking as in the second invention,
When the above-mentioned re-depressing line pressure increase control is executed, it is possible to avoid the problem that the re-depressing line pressure increase control is wasted, and this wasteful increase of the line pressure causes the V-belt to receive excessive tension and durability. Can be prevented from decreasing.

In the third aspect of the invention, the re-depressing line pressure increasing means increases the re-depressing line pressure increase only when the actual speed ratio of the continuously variable transmission is higher than the set speed ratio. Execute control.

When the actual speed ratio of the continuously variable transmission is already at the low speed side speed ratio which is equal to or higher than the set speed ratio, the response delay of the downshift speed does not pose a problem, and it does not occur like the third invention. When the above-mentioned re-depressing line pressure increase control is executed only when the actual gear ratio of the multi-speed transmission is a high-speed gear ratio that is less than the set gear ratio, avoid the problem that the re-depressing line pressure increase control is wasted. Therefore, it is possible to prevent the durability of the V-belt from being lowered due to the excessive tension of the V-belt due to the unnecessary increase of the line pressure.

In the fourth aspect of the present invention, the re-depressing detection means re-depresses when the prime mover is changed from the low load demand state to the high load demand state when the throttle opening of the prime mover is increased from less than a minute set value. Suppose

When the throttle opening of the prime mover is increased from the above-mentioned minute set value or more, even though the prime mover is changed from the low load demand state to the high load demand state, the line pressure is originally not so high. When the throttle opening is re-depressed when the throttle opening is increased from less than the minute set value as in the fourth aspect of the invention, the response delay of the downshift is not a problem. As a result, it is possible to prevent the line pressure increase control at the time of re-depressing from being wasted, and it is possible to prevent the V belt from receiving an excessive tension due to the useless increase of the line pressure and to reduce the durability.

In the fifth aspect of the present invention, the re-depressing detection means performs re-depression when the prime mover is changed from the low load demand state to the high load demand state when the throttle opening of the prime mover increases by more than a set value. Suppose there is.

When the increase of the throttle opening is less than the above-mentioned set value, even though the prime mover is changed from the low load demand state to the high load demand state, the gear ratio change amount due to the downshift is originally small. Therefore, the response delay of the downshift is not a problem, and when the re-depression is performed when the increase of the throttle opening is equal to or more than the set value as in the fifth invention, the result is As a result, it is possible to prevent the line pressure increase control at the time of re-depressing from being useless, and it is possible to prevent the V belt from receiving an excessive tension due to the useless increase of the line pressure and to reduce the durability.

In the sixth aspect of the invention, the time measuring means measures the elapsed time after the re-depression, and the re-depressing line pressure increasing means until the measured elapsed time reaches the set time. The line pressure rise control is executed. In this case, it is possible to avoid the foolishness of wasting the line pressure increase control during re-depression for eliminating the response delay of the downshift after the downshift is completed. It is possible to prevent the V-belt from receiving an excessive tension due to an increase in the line pressure and to reduce the durability.

In the seventh aspect of the invention, the set time is determined in correspondence with the response delay time of the downshift gear shift caused by the depression again. Therefore, in the seventh aspect of the invention, the operation and effect of the sixth aspect of the invention can be made more reliable, which is very useful.

[0029]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 exemplifies a line pressure control device for a V-belt type continuously variable transmission according to the present invention together with a shift control device, wherein 1 is a primary pulley as an input pulley to which the rotation of an engine (motor) not shown is input. Reference numerals 2 and 3 respectively denote secondary pulleys as output pulleys that output rotation after shifting. A V-belt 3 is wound around the primary pulley 1 and the secondary pulley 2,
It is possible to change the transmission ratio between the pulleys, that is, the gear ratio in a stepless manner by changing the winding arc diameter of the V belt 3 with respect to 2.

Therefore, in the primary pulley 1, the movable flange 1b forming the pulley V groove facing the fixed flange 1a is displaceable in the axial direction, and the secondary pulley 2
Also, the movable flange 2b forming the pulley V groove facing the fixed flange 2a can be displaced in the axial direction. Then, the shift control pressure P _S is applied to the movable flange 1b in the direction toward the fixed flange 1a, and the line pressure P _L is applied to the movable flange 2b in the direction toward the fixed flange 2a, so that the shift control pressure P _S and the line It is assumed that the diameter of the circular arc around which the V-belt 3 is wound around the pulleys 1 and 2 is changed steplessly in accordance with the pressure difference from the pressure P _L to perform continuously variable transmission.

The line pressure control system for controlling the line pressure P _L will be described below.
A pressure regulator valve 12 for adjusting the hydraulic fluid from now on to a line pressure P _L; a pressure modifier valve 13 for supplying a line pressure control modifier pressure P _m to the pressure regulator valve; (A) A line pressure solenoid 14 for controlling the valve 13 and a pilot valve 15 for supplying a constant pressure P _C to the solenoid.

The pressure regulator valve 12, while leakage of hydraulic oil from the pressure source 11 to the circuit 16, also with a drain from the drain port 12 _a as required line pressure according to the modifier pressure P _m P _L Regulate to. The pilot valve 15 supplies a leakage oil from the circuit 16 in the constant pressure P _C to the line pressure solenoid 14, the line pressure solenoid 14 in the duty pressure P _D corresponding to a constant pressure P _C in the drive duty D modifier valve 13 Apply to. The modifier valve 13 makes the oil leaked from the circuit 16 a modifier pressure P _m according to the duty pressure P _D , and thus the drive duty D of the line pressure solenoid 14, and applies this to the pressure regulator valve 12 to apply the line pressure P _L. Contribute to the above control of. Therefore, the line pressure P _L can be controlled by adjusting the drive duty D of the line pressure solenoid 14, and the solenoid drive duty D is determined by the controller 17 as described later.

The controller 17 also performs gear shift control. For this gear shift control and the above line pressure control, the controller 17 sends a signal from the throttle opening sensor 18 for detecting the engine throttle opening TVO to the primary pulley 1. Signal from the primary pulley rotation sensor 19 for detecting the rotation speed N _pri of the secondary pulley 2
The operation is performed according to the signal from the secondary pulley rotation sensor 20 that detects the rotation speed (corresponding to the vehicle speed) N _sec , the signal from the engine rotation sensor 27 that detects the engine rotation speed N _e , and the traveling mode desired by the driver. The signal from the inhibitor switch 28 for detecting the selected range of the manual valve (not shown) is input.

Next, the shift control system will be described. This shift control system comprises a shift control valve 21 for determining the shift control pressure P _S , a shift link 22, and a step motor 23. One end of the speed change link 22 is connected to a shifter 24 that is displaced together with the primary pulley movable flange 1b, the other end is connected to be driven by a step motor 23, and both ends are pivotally attached to a spool 21a of the speed change control valve 21. . Here, the shift control valve 2
Reference numeral 1 is for reducing the line pressure P _L from the circuit 25 to create the shift control pressure P _S in the circuit 26. When the spool 21a is raised in the drawing, the shift control pressure circuit 26 is set to the line pressure circuit 2
5, the shift control pressure P _S is increased, and the spool 21a
When it is lowered in the figure, the shift control pressure circuit 26 is connected to the drain port 21b to reduce the shift control pressure P _S , and the stroke of the spool 21a is controlled by the step motor 23 via the shift link 22. Then, the rotational position of the step motor 21 is determined by the controller 17, and the following shift control is executed accordingly.

In this gear change control, the controller 17
For example, based on a map corresponding to the shift control characteristic shown in FIG. 2, the target input rotation speed N _i is calculated from the vehicle speed N _sec and the throttle opening TVO, and a shift command corresponding to this is input to the step motor 23. Emit. As a result, the step motor 23 comes to the rotational position as instructed, and the speed change link 2
2 is rotated around the shifter 24 to stroke the shift control valve spool 21a. As a result, the shift control valve 21
Connects the circuit 26 to the line pressure circuit 25 and the drain port 2
1b is deviated from the equilibrium position where the same degree of communication is made,
By changing the speed change control pressure P _S, the movable flange 1b of the pulleys 1, 2, 2b speed change ratio by displacement is Kitasa has a gear ratio corresponding to the target input rotational speed N _i.

As the gear shift progresses, the movable flange 1b of the primary pulley 1 rotates the gear shift link 22 around the step motor 23 through the shifter 24 so as to return the gear shift control valve spool 21a to the original stroke position.
When the speed change ratio reaches the speed change ratio corresponding to the target input rotation speed N _i , the speed change control valve 21 returns to the equilibrium position to end the speed change control, and the target speed change ratio can be maintained.

Note that the controller 17 has a configuration as shown in FIG. 3 for controlling the line pressure P _L , but it goes without saying that it may be of a type that executes a flowchart for performing a similar operation. The speed ratio calculator 31 calculates a speed ratio e of a torque converter (not shown) interposed between the engine and the primary pulley 1 as e =
Calculated by N _e / N _pri , the torque ratio calculation unit 32 retrieves the torque ratio t of the torque converter from the torque converter performance diagram illustrated in FIG.

The engine torque estimating section 33 is, for example, as shown in FIG.
Based on the engine performance diagram shown in, the engine speed N _e
Also, the engine torque T _e is obtained by searching from the throttle opening TVO. The input torque estimation unit 34 includes a lockup signal L / that directly connects input / output elements of the torque converter.
Depending on the presence / absence of U, the transmission input torque T _i is multiplied by the engine torque T _e and the torque ratio t at the time of non-lockup T
_i = T _e × t, and when lockup occurs, the engine torque T _e is directly used as the transmission input torque T _i .

The gear ratio calculation unit 35 is used for input / output of the continuously variable transmission.
Transmission ratio i between pulleys is i = N_sec/ N _priCalculated by
The request line pressure calculation unit 36 uses the request as shown in FIG. 6, for example.
Transmission input torque T based on line pressure characteristics_iShift each time
Required line pressure P corresponding to ratio i₀To search. Far here
The heart pressure calculation unit 37 determines the line pressure P_LSecondary acting
Centrifugal pressure P to pulley 2₁To P₁= K ・ N_sec ²(However,
K is a constant) and the compensator 38 calculates
Pressure P₀To centrifugal pressure P₁Value P obtained by subtracting₀−P ₁The goal
The line pressure is input to the target line pressure selection unit 39.

Based on the throttle opening TVO detected by the sensor 18, the actual gear ratio i calculated by the gear ratio calculation unit 35, and the signal from the inhibitor switch 28, the line pressure determining unit 40 during the re-depressing operation is performed as shown in FIG. The control program shown in (1) is executed by a regular interruption to determine the line pressure P ₃ at the time of re-depressing in order to eliminate the response delay of the downshift shift at the time of re-depressing. First, in step 51, the flag FLAG is checked to determine whether or not the line pressure increase control during re-depressing has already been performed, FLAG = 1.
Determine by whether or not.

Next, at step 52, based on the signal from the inhibitor switch 28, it is checked whether or not the selected range is the forward traveling range which does not require engine braking. Other than this range, as described above regarding the forward traveling range and the reverse traveling range that require engine braking, the response delay of downshifting due to the re-depressing of the accelerator pedal does not cause a problem, Since the line pressure increase control is unnecessary, the control is ended as it is, and the above-mentioned setting and output of the line pressure P ₃ at the time of re-depression is not performed.

In the next step 53, the gear ratio calculation unit 35
It is determined whether or not the actual gear ratio i calculated in step 1 is in the high speed gear ratio range below the set gear ratio i _S. Here, the set gear ratio i _S is the lower limit value of the gear ratio range (low speed gear ratio range) in which the response delay of the downshift gear change due to the re-depression is not a problem. Therefore, the fact that the actual gear ratio i is in the high speed gear ratio range that is less than the set gear ratio i _{S as} described above means that a delay in gear shift response causes a problem when a downshift is performed due to a re-depression from the gear ratio range. It means that it is a gear ratio range that increases as much as possible.

Therefore, if it is determined in step 53 that the gear ratio is not within the relevant gear ratio range, the response delay of the downshift due to the re-depression does not pose a problem, and the line pressure increase control during re-depression according to the present invention is unnecessary. Therefore, the control is terminated as it is, and the line pressure P ₃ at the time of re-depressing is not set and output.

Step 5 corresponding to the re-depression detecting means
In No. 4, when the throttle opening TVO detected by the sensor 18 is increased by depressing the accelerator pedal from a minute set value such as 1/32 opening and the opening increase amount is equal to or larger than the set increase amount. Therefore, it is determined that the accelerator pedal is depressed again. Here, the above-mentioned minute set value of the throttle opening is a throttle opening value such that the response delay of downshifting due to the re-depressing becomes a problem when the re-depressing is accompanied by an increase in the throttle opening. Use a minute setting value. When the throttle opening degree TVO is increased from the minute set value, the setting increase amount of the throttle opening degree is less than the setting increase amount, and there is no problem of a response delay in downshifting due to re-depressing. Such an amount is set as the set increase amount of the throttle opening.

Therefore, if it is determined in step 54 that the pedal is not re-depressed, the response delay of the downshift due to the re-depression does not pose a problem and the line pressure increase control during re-depression according to the present invention is unnecessary. The control is terminated as it is, and the above-mentioned re-depressing line pressure P ₃ is not set and output.

However, if it is determined in step 54 that the re-depression has been performed so that the response delay of the downshift gear shift caused by the re-depression becomes a problem, the re-depression line pressure increase control according to the present invention is started in step 55. The flag FLAG is set to 1 so as to indicate that, and in step 56, the timer TM for measuring the elapsed time from the instant is reset to 0.

Then, in steps 57 and 58 corresponding to the re-depressing line pressure increasing means, the re-depressing line pressure P ₃ for each actual gear ratio i is obtained by searching based on the map corresponding to FIG. 8, for example. The line pressure P ₃ at the time of re-depression is output to the target line pressure selection unit 39. Here, the line pressure P ₃ at the time of re-depressing is set to a line pressure value at which the response delay of the downshift transmission due to the re-depressing does not become a problem, and the line pressure command corresponding to the transmission input torque from the compensator 38 is given. Of course, it is higher than the value P ₀ -P ₁ .

Thereafter, in step 55, the flag FLA is set.
Since G is set to 1, step 51 controls the control.
We will proceed to 59, and this station, which is equivalent to a timekeeping means,
In step 59, the above timer TM is incremented,
Line pressure P when re-depressing ₃After the output of
That is, the line pressure increase control during re-depression according to the present invention
Measures the elapsed time since the start of. And the next
In step 60, the time measured by this timer TM
The elapsed time is the set time TM_SCheck whether or not
And set time TM_SUntil the time elapses
Is the line pressure increase control started during re-depression due to light?
Set time TM_SControl until the time elapses.
Line pressure P when re-depressing by advancing to 57, 58₃The goal
The line pressure selecting section 39 continues to output and the
Continues to control the line pressure rise when depressing.

However, after it is determined in step 60 that the timer TM has reached the set time TM _S , that is, the set time TM _S has elapsed since the re-depression line pressure increase control according to the present invention was started. After that, the steps 57 and 58 are skipped and the line pressure P ₃ at the time of re-depression is set.
And the output to the target line pressure selection unit 39 are terminated, and the flag FLAG is reset to 0 in step 61.

Here, the set time TM _S is determined in correspondence with the response delay time of downshift gear shift accompanying re-depression, and only during this response delay time, the line pressure increase control during re-depression according to the present invention is performed. It is needless to say that it is preferable to carry out the process because the line pressure is not unnecessarily increased.

When the re-depression line pressure P ₃ from the re-depression line pressure determining unit 40 is input, the target line pressure selection unit 39 uses the input re-depression line pressure command value P ₃ as the target line pressure. The line pressure command value P ₀ -P ₁ from the compensator 38 is supplied as a target line pressure to the limiter 42 while the line pressure P ₃ at the time of re-depressing is not supplied to the limiter 42, and the target line pressure is selected. Shall be performed.

The limiter 42 is set with an allowable maximum line pressure as illustrated in FIG. 9, so that the upper limit of the target line pressure input as described above does not exceed the allowable maximum line pressure. And the target line pressure P _L.

Line pressure solenoid duty determining unit 43
Determines the duty D corresponding to the above target line pressure P _L based on the map as shown in FIG. 10, and outputs this to the line pressure solenoid 14. Solenoid 1 here
4 applies a constant pressure P _C from the pilot valve 15 to the modifier valve 13 with a duty pressure P _D according to the drive duty _D , and the modifier valve 13 applies the duty D
A modifier pressure P _m according to the above is applied to the pressure regulator valve 12, and the pressure regulator valve 12
Adjusts the hydraulic oil from the pressure source 11 to the line pressure P _L according to the duty D. As described above, the line pressure is controlled to the target line pressure P _L set as described above.

By the way, in this example, the engine breaker is
In the forward drive range that does not require a key (step 52), and
The gear ratio i is the set gear ratio i_SHigh speed gear ratio range of less than
In the meantime (step 53), the throttle opening TVO is set minutely.
Accelerator to increase from the fixed value 1/32 by more than the set increment
If there is another stepping on Dal (step 54), this stepping on again
Downshift shift response delay due to inclusion becomes a problem
Therefore, the line pressure P _LThe transmission input torque is compatible with normal
Value P₀−P₁Line pressure command value P when re-depressing from₃On
Downshift due to re-depression
Eliminating the shift response delay of shifting by increasing the line pressure
be able to.

[0055] Further, the re-depression when the line pressure increase control, when the set time TM _S corresponding to the shift response delay from the start of the control has passed (step 60), since to terminate, re depression line pressure As a result, the ascending control will not be unnecessarily continued even after the delay in the gear shift response to be eliminated, and the wasteful increase in the line pressure will unnecessarily increase the tension of the V-belt and reduce its durability. The harmful effect can be eliminated.

[0056]

As described above, the line pressure control device for the V-belt type continuously variable transmission according to the first aspect of the present invention changes the low load demand state of the prime mover to the high load demand state by re-depressing the accelerator pedal. At the time of switching, the line pressure of the V-belt type continuously variable transmission is configured to be increased to the line pressure value during re-depression that is higher than the normal value corresponding to the transmission input torque. It is possible to eliminate the response delay of the downshift transmission due to the re-depressing, and a problem that has occurred in the conventional V-belt type continuously variable transmission, that is, the response delay of the downshift when re-depressing is large, and the driver feels strange. It is possible to solve the conventional problem of giving.

A line pressure control device for a V-belt type continuously variable transmission according to a second aspect of the present invention, as set forth in claim 2, only when the selected range of the continuously variable transmission is a forward traveling range that does not require engine braking. Since it is configured to execute the above-mentioned re-depressing line pressure increase control, in a range in which the response delay of the downshift is not a problem, such as the forward travel range for engine braking and the reverse travel range, It is possible to avoid the problem that the line pressure increase control at the time of re-depressing is not wasted, and the wasteful line pressure increase causes the V-belt to receive excessive tension and reduce the durability.

A line pressure control device for a V-belt type continuously variable transmission according to a third aspect of the present invention, when the actual gear ratio of the continuously variable transmission is a gear ratio on the high speed side which is less than a set gear ratio, as described in claim 3. As long as it is configured to execute the line pressure increase control at the time of re-depressing, there is no problem with the response delay of the downshift, and the re-depressing is performed when the speed ratio is lower than the set speed ratio. It is possible to prevent the V-belt from being subjected to excessive tension due to this useless increase of the line pressure and the durability being deteriorated.

According to a fourth aspect of the present invention, there is provided a line pressure control device for a V-belt type continuously variable transmission, wherein when the throttle opening of the prime mover is increased from less than a minute set value, the above-mentioned operation is performed. Since the line pressure increase control at the time of re-depressing should be performed and it is at the time of re-depressing, the response delay of the downshift is not a problem.
It is possible to prevent the line pressure increase control at the time of re-depressing from being wasted when the throttle opening is increased from the above-mentioned minute set value or more, and this useless increase of the line pressure causes the V belt to generate an excessive tension. The durability is not lowered.

According to a fifth aspect of the present invention, there is provided a line pressure control device for a V-belt type continuously variable transmission, wherein when the throttle opening of the prime mover increases by more than a preset value, the above-mentioned Line pressure rise control should be performed when depressing,
Since the configuration is such that the re-depression is performed, it is possible to prevent the line pressure increase control at the time of re-depression from being wasted when a small throttle opening is increased without causing a response delay in the downshift. This prevents the V-belt from being subjected to excessive tension due to this useless increase in line pressure, resulting in a decrease in durability.

According to a sixth aspect of the present invention, there is provided a line pressure control device for a V-belt type continuously variable transmission, wherein:
Since the above-mentioned re-depressing line pressure increase control is executed, after the down-shifting accompanying the re-depressing is completed, the re-depressing line pressure increasing control for eliminating the response delay of the down-shifting is performed. It is possible to avoid unnecessary foolishness, and it is possible to prevent the durability from being lowered due to the excessive tension of the V-belt due to the unnecessary increase of the line pressure.

In a line pressure control device for a V-belt type continuously variable transmission according to a seventh aspect of the present invention, the set time is made to correspond to the response delay time of the downshift gearshift caused by the re-depression. Since it is determined, the operational effect of the sixth aspect of the invention can be made more reliable and is very useful.

[Brief description of drawings]

FIG. 1 is a hydraulic control system diagram illustrating a line pressure control device for a V-belt type continuously variable transmission according to the present invention together with a shift control device.

FIG. 2 is a diagram showing a normal shift control pattern used for shift control in the same example.

FIG. 3 is a functional block diagram relating to a line pressure control unit of the controller in the example.

FIG. 4 is a performance diagram showing a relationship between a speed ratio and a torque ratio of the torque converter.

FIG. 5 is an engine performance diagram used to determine engine torque.

FIG. 6 is a diagram showing required line pressure characteristics defined by a transmission input torque and a gear ratio.

FIG. 7 is a flowchart showing a control program of a line pressure determining unit during re-depression in FIG.

FIG. 8 is a diagram showing a change characteristic of re-depression line pressure determined by the re-depression line pressure control program.

FIG. 9 is a characteristic diagram showing a limit value of an allowable maximum line pressure.

FIG. 10 is a relationship diagram of a line pressure solenoid duty with respect to a target line pressure.

[Explanation of symbols]

 1 Primary pulley 1b Movable flange 2 Secondary pulley 2b Movable flange 3 V belt 11 Pressure source 12 Pressure regulator valve 13 Pressure modifier valve 14 Line pressure solenoid 15 Pilot valve 17 Controller 18 Throttle opening sensor 19 Primary pulley rotation sensor 20 Secondary pulley rotation Sensor 21 Shift control valve 22 Shift link 23 Step motor 24 Shifter 25 Line pressure circuit 26 Shift control pressure circuit 27 Engine rotation sensor 28 Inhibitor switch 31 Speed ratio calculation unit 32 Torque ratio calculation unit 33 Engine torque estimation unit 34 Input torque estimation unit 35 Gear ratio calculation unit 36 Required line pressure calculation unit 37 Centrifugal pressure calculation unit 38 Compensator 39 Target line pressure selection unit 40 Line pressure determination unit during re-depression 42 Limiter 43 Line pressure solenoid duty determination unit

Claims (7)

[Claims] 1. A line pressure is applied to a movable flange of one of a pair of pulleys around which a V belt is wound, and a line pressure is reduced to a movable flange of the other pulley by a shift control valve. In the V-belt type continuously variable transmission in which the transmission control pressure is applied to control the transmission ratio steplessly by the pressure difference between the transmission control pressure and the line pressure, the prime mover in the preceding stage of the continuously variable transmission is A re-depressing detection means for detecting a change from a low load demand state to a high load demand state by re-depressing the accelerator pedal, and when the re-depression is detected by the means, the line pressure is adjusted to a value corresponding to the transmission input torque. A line pressure control device for a V-belt type continuously variable transmission, comprising: a re-depressing line pressure increasing means for increasing a line pressure value during re-depressing higher than a normal value. 2. The re-depressing line pressure increasing means according to claim 1, only when the selection range of the continuously variable transmission is a forward traveling range that does not require engine braking.
A line pressure control device for a V-belt type continuously variable transmission, which is configured to execute the above-described line pressure increase control when the pedal is depressed again. 3. The re-depressing line pressure increasing means according to claim 1 or 2, only when the actual speed ratio of the continuously variable transmission is a high speed side speed ratio lower than a set speed ratio. A line pressure control device for a V-belt type continuously variable transmission, which is configured to execute a line pressure increase control. 4. The re-depressing detection means according to claim 1, wherein the re-pressing detection means determines that the prime mover is in a low load request state when the throttle opening of the prime mover is increased from less than a minute set value. A line pressure control device for a V-belt type continuously variable transmission, characterized in that it is configured such that a re-depression is performed in a high load demand state. 5. The re-depressing detection means according to claim 4, wherein when the throttle opening of the prime mover has increased by more than a set value, the prime mover is reset from the low load demand state to the high load demand state. A line pressure control device for a V-belt type continuously variable transmission, which is configured to be depressed. 6. The time-lapse means for measuring the elapsed time after re-depressing according to any one of claims 1 to 5, wherein the re-depressing line pressure increase means is an elapsed time measured by the time-measuring means. In response to, the line pressure of the V-belt type continuously variable transmission is configured to execute the line pressure increase control at the time of re-depressing until the elapsed time after the re-depressing reaches a set time. Control device. 7. The line pressure control device for a V-belt type continuously variable transmission according to claim 6, wherein the set time is set in correspondence with a response delay time of a downshift shift accompanying the re-depression. .