JPH09280361A - Control device for continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize shift control of a continuously variable transmission. SOLUTION: A target primary pressure (Ppmin) where no slippage of belt occurs and a target transmission gear ratio can be accomplished is calculated [B(1)] and a basic line pressure (Plprs st) is calculated [B(2)]. A line pressure correction coefficient (GainPL) at the time of transition of shifting is calculated at B(4) in reference to a ratio (GainPP) between an actual primary pressure (Ppsen) calculated at B(3) and the target primary pressure (Ppmin) is calculated. After this operation, the value Plbrs st is corrected by GainPL at B(5) to calculated a final output line pressure (Plprs) and then a solenoid valve 9 is feed-back controlled [B(6)], [B(7)]. With such an arrangement as above, since the line pressure control can be made most suitable at the transition time of shifting in reference to a hydraulic pressure of the primary pressure where a slippage of the belt actually occurs, and deteriorations in durability and fuel consumption caused by excessive tension of the belt can be positively restricted while a slippage of a belt is being positively prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for improving a control device for a continuously variable transmission, which is interposed, for example, between a power source (engine or the like) and a drive shaft, and more particularly to a technique for improving control during a gear transition. Regarding

[0002]

2. Description of the Related Art For example, the effective diameter can be changed continuously.
One pulley and a belt that is wrapped between both pulleys,
A line pressure (driven side fluid pressure) is supplied to the actuator of one pulley, and the line pressure is used as the original pressure for the gear change control to the actuator of the other pulley. In a shift control device of a continuously variable transmission (CVT), which is configured to supply a shift pressure (driving side fluid pressure) (oil amount) adjusted to a predetermined pressure via a gear to perform a continuously variable shift, the line pressure is , Is generally set to meet the following requirements.

That is, the belt does not slip. → Higher line pressure is better. The durability of each part is not impaired due to the excessive belt pressing force, and the rotational friction does not become excessive. → The line pressure should be low. Do not cause deterioration of fuel efficiency due to oil pump loss.
→ The line pressure should be low.

Furthermore, in order to prevent the belt from slipping during a gear shift transition such as a downshift, a line pressure is temporarily increased during a gear shift transition in order to provide an appropriate hydraulic pressure according to the gear shift transition. It is disclosed in Japanese Patent Publication No. 63-661, Japanese Patent Publication No. 59292/1993.

[0005]

However, as a specific example of how much the hydraulic pressure should be increased during a gear shift transition, Japanese Patent Publication No. 63-661 discloses that a solenoid valve is used for ON / OFF switching (two stages). The line pressure switching is only disclosed, and it is not disclosed in Japanese Patent Publication No. 59292/1993, and it is not possible to optimize the line pressure supply at the time of gear shift transition in view of the above items.

Therefore, the applicant of the present application filed Japanese Patent Application No. 7-8.
In No. 4077, the target line pressure is temporarily increased and corrected by a correction amount at the time of a shift transition set based on the engine torque, the shift speed, and the like during the shift.
A control device for a continuously variable transmission capable of supplying a necessary and sufficient line pressure that does not impair the durability and fuel consumption of the continuously variable transmission (especially the belt) while surely preventing the slippage of the belt during gear shifting. Proposed.

However, even in this case, the correction amount at the time of the shift transition is confirmed and set in advance by experiments in correspondence with a plurality of parameters for each model (according to the engine torque, the shift speed, etc.). However, there was a problem that the number of development / experimental man-hours could not be reduced. In addition, since the hydraulic pressure of the primary pressure that actually causes belt slippage is not taken into consideration, it is necessary to give a higher line pressure (margin) in order to reliably avoid belt slippage, considering product variations and the like. However, there was a fear that the adverse effects on durability and fuel economy could not be completely eliminated.

The present invention has been made in view of the above circumstances, and further improves the accuracy of line pressure control during a gear shift transition by considering the hydraulic pressure of the primary pressure at which belt slip actually occurs. As a result, the durability of the power transmission member (for example, a belt) is reliably prevented while preventing slippage.
An object of the present invention is to provide a control device for a continuously variable transmission that can surely eliminate deterioration of fuel consumption and the like.

[0009]

Therefore, according to the invention described in claim 1, as shown in FIG. 1, a driving side rotating member which receives the rotating force of a power source, a driven side rotating member, and these And a drive-side contact turning radius that is a distance from a rotation center of a contact position between the drive-side rotating member and the power-transmitting member, By continuously changing the driven-side contact rotation radius, which is the distance from the center of rotation of the contact position between the driven-side rotating member and the power transmission member, the driving-side rotating member and the driven-side member A control device for a continuously variable transmission, which is capable of continuously setting a speed ratio between a rotary member and
A driving fluid pressure target value setting means for setting a driving fluid pressure target value, a driven fluid pressure target value setting means for setting a driven fluid pressure target value, and the driven fluid pressure, The pressure control means for controlling the target value set by the driven side fluid pressure target value setting means, and the driven side fluid pressure controlled by the pressure control means as a source pressure, through a flow control valve, Based on the flow rate control means for controlling the drive side fluid pressure to the target value set by the drive side fluid pressure target value setting means, and the target value of the drive side fluid pressure at the time of gear shifting,
By the gear shift target value correcting means for correcting the target value set by the driven side fluid pressure target value setting means, and the pressure control means by the pressure control means so as to obtain the target value corrected by the gear shifting target value correction means. And a pressure-control-correction-means during shifting, which corrects the control of the driven-side fluid pressure.

According to the above construction, for example, while the target value of the drive side fluid pressure (hereinafter, also referred to as the shift pressure or the primary pressure) necessary for achieving the target gear ratio and preventing the belt from slipping is calculated. Since the driven side fluid pressure (hereinafter, also referred to as line pressure) is corrected so that the target value can be actually achieved, that is, the driving side fluid pressure at which belt slip actually occurs is taken into consideration. Since the driven-side fluid pressure (line pressure) control is performed during a gear shift transition, slippage of the power transmission member (for example, belt) can be reliably prevented, and durability of the belt is not impaired ( (There is no increase in rotational friction due to excessive tension), and by suppressing unnecessary work of the oil pump, it is possible to reliably prevent deterioration of fuel consumption and the like.

Further, unlike the conventional case, it is not necessary to perform a complicated work such as setting a correction amount at the time of gear shift transition with respect to a plurality of parameters, so that the number of man-hours for development and experiment can be greatly reduced. Therefore, it is possible to reduce the product cost. According to a second aspect of the present invention, the gear shift target value correction means sets the driven side fluid pressure in accordance with a ratio or a deviation between an actual driving side fluid pressure and a target value of the driving side fluid pressure. The target value set by the target value setting means is corrected.

With this configuration, the target value set by the driven-side fluid pressure target value setting means according to the deviation or ratio between the actual drive-side fluid pressure (shift pressure) and the target value. Since it is possible to compensate for variations in products, it is possible to prevent slippage of the power transmission member (for example, the belt) more reliably, and do not impair the durability of the belt (rotation friction due to excessive tension). It is also possible to reliably prevent deterioration of fuel consumption and the like by suppressing unnecessary work of the oil pump.

According to a third aspect of the present invention, the gear shift target value correction means calculates a time derivative of a ratio or deviation between the actual drive side fluid pressure and the drive side fluid pressure target value. The larger the calculated time differential value, the larger the target value set by the driven-side fluid pressure target value setting means.

With this configuration, when the target value of the fluid pressure on the driving side changes, and the difference between the fluid pressure on the actual driving side and the actual pressure on the driving fluid becomes large, a high responsiveness is provided to suppress the difference. Since the target value of the driven-side fluid pressure can be corrected according to the magnitude of the deviation, the driven-side fluid pressure can be advanced and corrected, and the delay of the control system can be prevented. In other words, when the actual drive-side fluid pressure has a deviation from the target drive-side fluid pressure (for example, when it has a decreasing tendency), the greater the degree of the deviation (decreasing tendency), the driven-side fluid pressure. Since it greatly changes (increases), the delay of the control system can be prevented, so that the responsiveness of the driven side fluid pressure (line pressure) control decreases and the driven side fluid pressure undershoot, overshoot, etc. It is possible to suppress the occurrence of the above-mentioned problem as much as possible, and thus it is possible to more reliably prevent the belt slip and reduce the fuel consumption.

According to a fourth aspect of the present invention, the drive-side rotating member is a pulley whose effective winding radius can be changed.
The driven side rotating member is a pulley whose effective winding radius can be changed, and the power transmission member is a winding conductive medium wound around these pulleys.

In this way, by adopting a so-called movable pulley type continuously variable transmission that is actually used for vehicles and the like, it is advantageous in terms of cost reduction, common parts, durability, maintenance and the like. Will be things.

[0017]

As described above, according to the first aspect of the present invention, slippage of the power transmission member can be reliably prevented even during a gear shift transition, and the durability of the continuously variable transmission is not impaired. It is possible to suppress an increase in rotational friction and to supply a necessary and sufficient line pressure that does not cause deterioration of fuel consumption due to oil pump loss and the like, thereby providing a good control device for a continuously variable transmission. .

According to the second aspect of the present invention, the target set by the driven-side fluid pressure target value setting means in accordance with the deviation or ratio between the actual driving-side fluid pressure and the target value. Since the value can be corrected, it is possible to cope with product variations, etc., and it is possible to prevent slippage of the power transmission member more reliably, and do not impair the durability of the belt (increasing rotational friction due to excessive tension). In addition, by suppressing unnecessary work of the oil pump, it is possible to reliably prevent deterioration of fuel consumption and the like.

According to the third aspect of the present invention, it is possible to prevent the delay of the control system during the transition of the gear shift, thereby reducing the responsiveness of the driven side fluid pressure (line pressure) control and the driven side fluid pressure. The occurrence of undershoot, overshoot, and the like can be suppressed as much as possible, so that it is possible to more reliably prevent belt slip and reduce fuel consumption. According to the invention described in claim 4, by adopting a so-called movable pulley type continuously variable transmission that is actually adopted for vehicles and the like, cost reduction, common parts, durability, maintenance, etc. It can be advantageous in terms of.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 2 is a system configuration diagram according to the first embodiment of the present invention. A continuously variable transmission (CVT) 3 is provided on the output side of the engine 1 via a long travel damper (spring type damper for absorbing rotation fluctuation) 2. In a system in which a starting clutch 15 described later is interposed between the engine 1 and the continuously variable transmission 3 or a system in which a torque converter is interposed, the long travel damper 2 can be omitted.

The continuously variable transmission (CVT) 3 includes a primary pulley 4 on the engine 1 side, a secondary pulley 5 on the drive shaft (differential) side, rubber or metal wound between them, or a combination thereof. And a belt 6 made up of the secondary pulley 6 and the secondary pulley side actuator 5a (tension control hydraulic chamber) and the line pressure to the secondary pulley side actuator 5a (tension control hydraulic chamber). By changing the pulley-side belt winding effective diameter / the primary pulley-side belt winding effective diameter, the gear ratio can be changed steplessly. However, other CVTs such as a known toroidal type
Can also be used. That is, the continuously variable transmission 3 includes a drive-side rotating member that receives the rotational force of the power source, a driven-side rotating member, and a power transmission member that is interposed therebetween.
A drive-side contact rotation radius that is a distance from a rotation center of a contact position between the drive-side rotation member and the power transmission member, and a distance from a rotation center of a contact position between the driven-side rotation member and the power transmission member And a driven-side contact turning radius, which is a stepless relative speed change, capable of continuously setting the gear ratio between the driving-side rotating member and the driven-side rotating member. Any machine will do. The primary pulley 4 corresponds to the driving-side rotating member, the secondary pulley 5 corresponds to the driven-side rotating member, and the belt 6 corresponds to the power transmission member and the winding conduction medium.

The drive side fluid pressure for controlling the drive side contact turning radius according to the present invention corresponds to the shift pressure (primary pressure) in this embodiment. Further, the driven-side fluid pressure for controlling the driven-side contact turning radius according to the present invention corresponds to the line pressure in the present embodiment. Here, the line pressure is the hydraulic circuit 8 connected to the oil pump 7.
The hydraulic pressure in the hydraulic path provided inside is controlled by opening / closing driving (for example, duty control) an electromagnetic valve (line pressure solenoid valve) 9 having a relief function, and the shift pressure is controlled accordingly. The line pressure is used as a source pressure, and the flow rate is controlled by adjusting the opening degree of the flow rate control valve 17 through the opening / closing drive of the solenoid valve 10. The drive control of each of these valves is performed by the controller. It is controlled by 11. The solenoid valve 9
Corresponds to the hardware part of the pressure control means according to the present invention, and the solenoid valve 10 and the flow rate control valve 17 correspond to the hardware part of the flow rate control means according to the present invention.

That is, the controller 11 controls the shift pressure and the line pressure via the solenoid valve 9, the solenoid valve 10 and the flow rate control valve 17 so that the required gear ratio can be achieved in accordance with the traveling conditions and the like. The gear ratio is controlled to the target value. A starting clutch 15 is interposed between the output side (secondary pulley 5) of the continuously variable transmission 3 and the drive shaft side (for example, differential).
The clutch pressure to 5 is controlled by the solenoid valve 16, and this solenoid valve 16 is also controlled by the controller 11.

As will be described below, the controller 11 includes a drive side fluid pressure target value setting means, a driven side fluid pressure target value setting means, a pressure control means according to the present invention,
Functions as a flow rate control means, a gear shift target value correction means, and a gear shift pressure control correction means are provided by software.
The gear ratio for the control of (speed change pressure) and the line pressure, the controller 11, the actual input revolution speed Nin of the CVT 3 input to detect the (rotational speed N _E of the engine 3) (a primary pulley 4) Of the input side rotation sensor 12 that generates a pulse signal in synchronization with the rotation of the output side (secondary pulley 5) in order to detect the actual output speed No of the continuously variable transmission 3. Output side rotation sensor 13, throttle valve opening of engine 1 (throttle opening) TVO
Detection signals are input from a potentiometer type throttle sensor 14 or the like which generates a voltage signal corresponding to. Note that an engine rotation sensor can be used as the input rotation sensor 12 and a vehicle speed sensor can be used as the output rotation sensor 13.

Here, the shift control routine executed by the controller 11 in this embodiment will be described with reference to the control block diagram of FIG. It should be noted that this control is executed every predetermined unit time. First, block (1) [in the figure, B
It is written as (1). The same applies hereinafter], the target pressure (Ppmin) of the shift pressure (primary pressure) supplied to the primary pulley side actuator 4a (gear ratio control hydraulic chamber) is calculated. That is, the required minimum pressure (Ppmin) of the shift pressure (primary pressure) that can achieve the target speed ratio without the belt 6 slipping, that is, the target shift pressure (Ppmin) is calculated.

Specifically, this is achieved by executing the flowchart of FIG. That is, step 1 (in the figure, S
It is written as 1. The same applies hereinafter), in order to obtain the actual gear ratio (the gear ratio instructed from the controller 11, etc.) and the necessary minimum pressure (Ppmin) of the gear shift pressure corresponding to the engine torque,
First, the ratio (θ ₁ / θ) of the required minimum primary pressure (shift pressure) of each gear ratio to the gear ratio = 1 and the required minimum with the engine torque (or the input torque to the continuously variable transmission 3) It is determined by referring to a map set based on the relationship with the primary pressure. It should be noted that in the controller 11, the gear ratio is the vehicle speed VSP and the throttle opening TVO.
The gear ratio is set from the actual VSP, TVO, etc. by referring to a map or the like in which the gear ratio is determined based on Further, the gear ratio can be set so that the vehicle speed intended by the driver can be obtained while maintaining the desired engine operating state. In such a case, the engine operating condition with good fuel economy and exhaust performance can be maintained, so
This can be advantageous in terms of exhaust performance and the like.

Then, in step 2, the primary target (minimum) pressure (Ppmin) is obtained according to the following equation. Primary target (minimum) pressure (Ppmin) = engine torque × θ × magnification + offset amount The offset amount is a margin allowance. In addition, the gearshift target pressure (primary target pressure) (Ppmin) can also take into consideration centrifugal oil pressure generated in the primary pulley side actuator 4a. Next, in block (2),
Calculate the basic line pressure (Plprs st).

That is, the line pressure (Pl
prs; which will be described later) is based on the supply line pressure (basic line pressure) and a transient correction coefficient (GainPL; which will be described later) for preventing slippage of the belt 6 during a gear shift transient. Because it is set,
As a basis for obtaining the final line pressure (Plprs), first, the basic line pressure (Plprs st) is calculated.

The basic line pressure (Plprs st) can be calculated as follows, for example. That is, first, the movable wall 5 of the secondary pulley side actuator 5a
Calculate the required thrust (FS) of A.

That is, a desired gear ratio (secondary pulley side effective diameter / primary pulley effective diameter = primary pulley rotation speed / secondary pulley rotation speed, torque ratio) is generated without causing the belt 6 to slip on the primary pulley side. In order to achieve this, the thrust (pressing force) required of the movable wall 5A of the secondary pulley side actuator 5a is obtained. In addition, the primary pulley side actuator 4a,
Alternatively, if the thrust force (in other words, hydraulic pressure) of any one of the secondary pulley side actuators 5a is determined, the other thrust force can be theoretically determined from the relationship between the belt tension, the engine torque and the torque ratio.

Therefore, here, the primary pulley side 4a is determined from the primary minimum pressure (Ppmin) set in the block (1) and the area of the primary pulley side movable wall 4A so as to obtain a desired gear ratio without the belt slipping. Thrust (F
Since P) can be determined, the required secondary thrust (FS) is calculated based on this. Specifically, the required secondary thrust (FS) is obtained by executing the flowchart of FIG.

That is, in step 11, the required secondary thrust (FS) is calculated based on the following equation. Required secondary thrust (FS) = minimum primary pressure (Ppmi
n) x area of the primary pulley side movable wall 4A x coefficient 0-
Engine torque × coefficient 1 Coefficient 0 and coefficient 1 are coefficients determined by the gear ratio. Then, based on the required secondary thrust (FS), the required pressure on the secondary pulley side (basic line pressure (Plprs st) required to achieve the desired gear ratio without causing the belt 6 to slip on the primary pulley side). ] Is calculated.

Specifically, this basic line pressure (Plprs s
t) is obtained by executing the flowchart of FIG. That is, in step 21, the basic line pressure (Plprs st) is calculated based on the following equation. Basic line pressure (Plprs st) = [Required secondary thrust (F
S) -secondary pulley spring constant x contraction length] / area of movable wall 5A The secondary pulley spring constant is a spring for pushing back the movable wall 5A, which is housed in the secondary pulley-side actuator 5a, against line pressure. It is a constant (not shown). The basic line pressure (Plprs st) can also take into consideration centrifugal oil pressure generated in the secondary pulley side actuator 5a.

The shift target pressure (primary target pressure) (Ppmin) and the basic line pressure (Plprs st) may be obtained by searching a map or the like based on the gear ratio, engine torque, throttle valve opening, and the like. It is possible. Next, in the block (3), the ratio (GainPP = Ppmin / Ppsen × K,) between the target pressure (Ppmin) of the shift (primary) pressure calculated in the block (2) and the actual primary pressure (Ppsen).
K is a coefficient. However, GainPP ≧ 1.0. ).
The GainPP may be a deviation between the target pressure (Ppmin) of the shift pressure and the actual primary pressure (Ppsen) instead of the ratio.

The actual primary pressure (Ppsen) may be detected by a hydraulic sensor or may be calculated. As a method for calculating the actual primary pressure (Ppsen) by calculation, there is, for example, the one proposed by the applicant of the present application in Japanese Patent Application No. 8-27161. This method uses a line pressure (PL; detected by a sensor) that is obtained from the opening area ratio Ar, which is the ratio of the opening area of the inflow section to the opening area of the outflow section of the spool valve (flow control valve 17), and the duty ratio of the solenoid valve 9. You may)
Therefore, the actual primary pressure (Ppsen) is estimated and detected according to the following equation.

Ppsen = (1 + Ar ² ) / Ar ² × line pressure (PL) Next, in block (4), Ga obtained in block (3) is calculated.
InPP is multiplied by the correction coefficient KGPP to calculate the line pressure correction coefficient (GainPL) at the time of shift transition. That is, the processing of GainPL = GainPP × KGPP is performed.

GainPP (= Ppmin / Ppsen × K)
Is the minimum pressure (Ppmi
n) and the actual primary pressure (Ppsen) are set based on the ratio (or deviation) to achieve the target minimum primary pressure (Ppmin) to prevent belt slip. This is because the degree of influence on the change of the gear ratio when the line pressure is controlled by changing the duty ratio of the solenoid valve 9 is taken into consideration.

That is, the target minimum primary pressure (Ppmin)
In order to achieve the above, if the line pressure is changed, the actual primary pressure (Ppsen) is changed accordingly, but at the same time, the gear ratio also changes to some extent. The ratio (gear ratio) between the actual input rotation speed Nin of the continuously variable transmission 3 detected by the sensor 12 and the actual output rotation speed No of the continuously variable transmission 3 detected by the output side rotation sensor 13 becomes a target value. (Or control so that the actual line pressure becomes the target line pressure) such as feedback control (control that is performed separately from the line pressure correction control during the shift transition), and the line pressure during the shift transition There is a fear that good control cannot be performed due to interference with the correction control (for example, control hunting), but with the above configuration, the target minimum primary pressure (Ppmi
If the degree of change of the line pressure when trying to achieve n) is taken into consideration, it is possible to suppress the occurrence of fear such as the control hunting.

If the line pressure is controlled as in this embodiment [the line pressure as the original pressure is controlled to control the shift pressure (primary pressure)], the winding diameters of both pulleys are Since it changes in the same direction, that is, both pulleys increase in the winding diameter increasing direction, a large gear ratio change does not occur, and belt slip can be easily suppressed by a slight increase in line pressure. , For example,
Higher control accuracy and lower cost compared to the case where the shift pressure is controlled to the target pressure via the solenoid valve 10 (and thus the flow control valve 17) based on the detection signal from the shift pressure sensor or the like. It becomes advantageous in terms of the above.

By the way, the line pressure correction coefficient (GainPL) during the shift transition is set during the downshift according to the flow chart shown in FIG. 7, and is gradually set to 1.0 (set in the steady state) with the lapse of time after the downshift is completed. Value). That is, in step 31,
For example, the current set speed ratio (target speed ratio) Nexti is compared with the final target steady-state speed ratio (final target speed ratio) Basei to determine whether or not a downshift is being performed.

If YES, downshift is in progress,
In order to suppress the belt slip, it is necessary to increase the line pressure via the line pressure correction coefficient (GainPL) at the time of gear shift transition, so the routine proceeds to step 32, and as described above, the line pressure correction coefficient (GainPL) at the time of gear shift transition is set. ) Is set to a predetermined value, and the process proceeds to block (5) described later. If NO, the downshift is completed, so it is determined that belt slip does not occur, and the routine proceeds to step 33, and at every predetermined time until the line pressure correction coefficient (GainPL) = 1.0 during shift transition. Then, GainPL is subtracted at a predetermined reduction rate, and the process proceeds to block (5) described later.

By so doing, belt slip during downshifting can be reliably suppressed with good responsiveness, while at the end of downshifting, a smooth steady state can be achieved while suppressing gear ratio shocks and the like due to sudden line pressure changes. It becomes possible to shift to. Then, in the block (5), the line pressure correction coefficient GainPL during the shift transition obtained in the block (4)
The basic line pressure (Pl
prs st) is multiplied by this to obtain the final output line pressure (Plprs).

That is, the processing of Plprs = Plprsst × GainPL is performed. In the next block (6), the actual line pressure from the line pressure sensor (may be the calculation result from Prssen, duty ratio, etc.) and the final output line pressure (Plprs) obtained in block (5), The deviation (Errpl) of is calculated.

In the following block (7), the deviation (Errp
l) is eliminated, the duty ratio of the solenoid valve 9 for controlling the line pressure is corrected by PI (proportional integration) control or the like,
It is output to the solenoid valve 9 as a duty signal (Plduty).
The final duty signal (Plduty) may have an upper limit value. In other words, the output line pressure
The hydraulic circuit 8 limits the pressure to a predetermined pressure (upper limit hydraulic pressure) in terms of function and structure. This ensures, for example, an abnormal increase in friction (when rotation becomes difficult) due to excessive increase in belt tension, damage to the belt 6, damage to the secondary pulley side actuator 5a and line pressure supply path, excessive drive of the oil pump, etc. Can be prevented. Further, it is possible to prevent the occurrence of control failure due to a calculation error or the like.

As described above, according to the first embodiment,
While calculating the target shift pressure (primary pressure, Ppmin) required to achieve the target gear ratio and prevent the belt 6 from slipping, the target shift pressure (primary pressure, Ppmin) is calculated.
So that the actual primary pressure (Ppse
n) and the minimum required target shift pressure (primary pressure, Ppmi
n)) and the line pressure is increased and corrected based on the ratio (or deviation), that is, the line pressure control during a gear shift transition in consideration of the hydraulic pressure of the primary pressure at which belt slip actually occurs. Since the power transmission member (for example, belt) can be surely prevented from slipping, durability of the belt is not impaired (no increase in rotational friction due to excessive tension), and the oil pump By suppressing the unnecessary work of, it is possible to reliably prevent deterioration of fuel consumption and the like.

Further, the coefficient K and the correction coefficient KG can be set without performing a complicated work such as setting a correction amount at the time of a shift transition for a plurality of parameters as in the conventional case.
By simply changing the PP setting, etc., it is possible to surely suppress belt slip and reduce fuel consumption, so it is possible to significantly reduce the number of man-hours for development and experimentation, thereby reducing the product cost. It will be possible. Next, a second embodiment of the present invention will be described.

In the second embodiment, in addition to the configuration of the first embodiment, the delay of the control system can be suppressed by performing the advance processing on the line pressure correction coefficient (GainPL) during the shift transition. It was done. Specifically, as shown in the control block diagram of FIG. 8, new blocks (8), blocks (9), and (10) are added to the control block diagram of the first embodiment. The block (8), the block (9), and the block (10) correspond to the advance processing means according to the present invention, and the controller 11 has the function as software.

That is, in the block (8), GainPP (=
Ppmin / Ppsen × K) is time-differentiated. That is, ΔGainPP
/ Δt [= DltGPP = (Current GainPP-Previous GainPP) /
[Predetermined unit time]. In the next block (9), Δ
GainPP / Δt (= DltGPP) is multiplied by the coefficient KD,
The advance process correction value KDGPP is obtained.

That is, KDGPP = ΔGainPP / Δt (= Dl
tGPP) × KD. The block (10) is similar to the block (3) of the first embodiment.
The shift process line pressure correction coefficient GainPL obtained in step (9) is added to the advance process correction value KDGPP obtained in the block (9) to obtain a final shift transition line pressure correction coefficient GainPL.
Set.

That is, the processing of GainPL = GainPL + KDGPP is performed. Block (8) to block (1
The process 0) is shown in the flowchart of FIG.

Then, after that, as in the first embodiment, the process proceeds to block (5), the line pressure correction coefficient GainPL during shift transition obtained in block (10) is read, and the basic value obtained in block (2) is obtained. The line pressure (Plprs st) is multiplied by this to obtain the final output line pressure (Plprs =), and the subsequent blocks (6) and (7) are executed.
As described above, according to the second embodiment, the advance processing correction value KDGPP is GainPP [= Ppmin / Ppsen × K,
Alternatively, it may be (Ppmin-Ppsen) × K], so the target pressure (Ppmin) of the primary (shift) pressure may change and the actual primary pressure (Ppsen) may change.
), The line pressure can be advanced and corrected with high responsivity (in other words, according to the magnitude of the deviation) so as to suppress the difference, so the delay of the control system As a result, it is possible to prevent the decrease in responsiveness of the line pressure control and the occurrence of undershoot and overshoot of the line pressure as much as possible, and it is possible to more reliably prevent the belt slip and reduce the fuel consumption. . That is, when the actual primary pressure has a deviation from the target primary pressure (for example, when it has a decreasing tendency), the greater the degree of the deviation (decreasing tendency), the more the line pressure is changed (increased). As a result, it is possible to prevent the delay of the control system, thereby suppressing the decrease in the responsiveness of the line pressure control and the occurrence of line pressure undershoot, overshoot, etc. It is possible to prevent and reduce fuel consumption.

The present invention can be applied to a control for increasing / decreasing the line pressure so that a target shift pressure (primary pressure) can be obtained at the time of shifting, and the application range is only for downshifting. It is not limited. Further, it is not limited to the setting method and the setting purpose of the target shift pressure and the target line pressure described in each of the above embodiments,
The target shift pressure and the target line pressure may be set based on other setting methods and purposes. And in the present invention,
The correction coefficient is set based on the ratio (or deviation) between the target primary pressure and the actual primary pressure, and is reflected in the line pressure control. However, the change in the target primary pressure is reflected in the line pressure control. Of course, the effect of the present invention can be obtained even if it is reflected. That is, the line pressure in the steady state may be corrected based on the target primary pressure at the time of shifting without detecting the actual primary pressure.

In each of the above-described embodiments, the line pressure correction amount at the time of shift transition is given as the correction coefficient GainPL (that is, Plprs = Plprs st × GainPL), but the basic line pressure (Plprs st) is not used. Of course, the line pressure correction amount (absolute amount) at the time of gear shift transition may be added or subtracted. Further, in each of the above-described embodiments, the power source has been described as an engine, but the present invention can also be applied to the case of using another power source.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of the present invention.

FIG. 2 is a system diagram showing a first embodiment of the present invention.

FIG. 3 is a control block diagram illustrating shift control according to the above embodiment.

[Fig. 4] Target pressure (Ppmin) of shift pressure (primary pressure)
Is a flowchart for calculating.

FIG. 5 is a flowchart for explaining calculation of required secondary thrust (FS).

FIG. 6 is a flowchart for explaining calculation of a basic line pressure (Plprs st).

FIG. 7 is a flowchart illustrating setting of a line pressure correction coefficient (GainPL) during a shift transition.

FIG. 8 is a control block diagram illustrating shift control according to the second embodiment.

9 is a flowchart showing blocks (8) to (10) in FIG.

[Explanation of symbols]

 1 engine 3 continuously variable transmission 4 primary pulley 4a primary pulley side actuator 5 secondary pulley 5a secondary pulley side actuator 6 belt 7 oil pump 8 hydraulic circuit 9 solenoid valve 10 solenoid valve 11 controller 12 input side rotation sensor 13 output side rotation sensor 14 Throttle sensor 17 Flow control valve

Claims (4)

[Claims] 1. A drive-side rotating member that receives a rotating force of a power source, a driven-side rotating member, and a power transmitting member that is interposed between the driving-side rotating member and the driven-side rotating member to transmit power between the two. A drive-side contact rotation radius that is the distance from the center of rotation of the contact position between the rotating member and the power transmission member, and a distance from the center of rotation of the contact position between the driven-side rotation member and the power transmission member. Control of a continuously variable transmission capable of continuously setting the gear ratio between the driving-side rotating member and the driven-side rotating member by continuously changing the driving-side contact turning radius and the driving-side contact turning radius. A driving side fluid pressure target value setting means for setting a driving side fluid pressure target value; a driven side fluid pressure target value setting means for setting a driven side fluid pressure target value; The side fluid pressure is set by the driven side fluid pressure target value setting means. A pressure control means for controlling to a constant target value, as a source pressure to the driven side the fluid pressure controlled by the pressure control means, through a flow control valve, the drive-side fluid pressure,
Flow rate control means for controlling to the target value set by the drive side fluid pressure target value setting means, and set by the driven side fluid pressure target value setting means based on the target value of the drive side fluid pressure at the time of shifting. Target value correction means for correcting the target value and a target value correction means for correcting the speed of the driven side fluid pressure by the pressure control means so that the target value is corrected by the target value correction means during the shift A control device for a continuously variable transmission, comprising: a pressure control correction means. 2. The driven-side fluid pressure target value setting means according to the ratio or deviation between the actual driving-side fluid pressure and the target value of the driving-side fluid pressure. The control device for the continuously variable transmission according to claim 1, which is a unit that corrects the target value set by the above. 3. The shift target value correcting means includes an actual drive side fluid pressure and a target value of the drive side fluid pressure,
And the advance processing means for correcting the target value set by the driven-side fluid pressure target value setting means as the calculated time differential value of the ratio or deviation increases. Claim 1 characterized in that
Alternatively, the control device for the continuously variable transmission according to claim 2. 4. The drive-side rotating member is a pulley whose effective winding radius can be changed, the driven-side rotating member is a pulley whose effective winding radius can be changed, and the power transmission member is The control device for a continuously variable transmission according to any one of claims 1 to 3, wherein the control device is a wound conductive medium that is wound around.