JP3351957B2 - Control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved technology for a control device of a continuously variable transmission interposed between a power source (engine or the like) and a drive shaft, and more particularly to an improved control technology during a shift transition. About.

[0002]

2. Description of the Related Art For example, the effective diameter can be changed continuously.
One pulley and a belt wound between both pulleys,
A line pressure (driven fluid pressure) is supplied to the actuator of one of the pulleys, and a shift control valve (flow control valve) is provided to the actuator of the other pulley using the line pressure as the original pressure for shifting control. A continuously variable transmission (CVT) in which a continuously variable transmission (CVT) is provided by supplying a transmission pressure (driving fluid pressure) (oil amount) adjusted to a predetermined pressure via a predetermined pressure through the line pressure. Is generally set to satisfy the following requirements.

That is, the belt does not slip. → Higher line pressure is better. The durability of each part should not be impaired by excessive belt pressing force, and the rotational friction should not be excessive. → The lower the line pressure, the better. Fuel consumption should not deteriorate due to oil pump loss.
→ The lower the line pressure, the better.

Further, a method of temporarily increasing the line pressure during a shift transition in order to provide an appropriate oil pressure according to the shift transition so as to prevent the belt from slipping during a shift transition such as a downshift, for example, It is disclosed in JP-B-63-661, JP-B-5-59292 and the like.

[0005]

However, a specific example of how much the oil pressure should be raised during a shift transition is disclosed in Japanese Patent Publication No. 63-661 in the case of ON / OFF switching (two stages) using a solenoid valve. The line pressure switching is merely disclosed, and Japanese Patent Publication No. 5-59292 is not disclosed, and it is not possible to optimize the supply of the line pressure during the shift transition based on the above.

[0006] For this reason, the applicant of the present invention has filed Japanese Patent Application No.
In No. 4077, at the time of shifting, the target line pressure is temporarily increased by a correction amount at the time of shifting, which is set based on the engine torque, the shifting speed, and the like.
A control device for a continuously variable transmission capable of supplying a necessary and sufficient line pressure without deteriorating the durability and fuel efficiency of a continuously variable transmission (particularly a belt or the like) while reliably preventing the belt from slipping during shifting. Proposed.

However, even in this case, the correction amount during the shift transition is confirmed and set in advance in accordance with a plurality of parameters (according to the engine torque, the shift speed, etc.) for each model by experiments or the like. Therefore, there is a problem in that it is not possible to reduce development man-hours and experimental man-hours. Also, since the hydraulic pressure of the primary pressure at which the belt slips actually occurs is not taken into consideration, it is necessary to give a higher line pressure (margin) in order to reliably avoid the belt slip when considering product variations and the like. There was a fear that the adverse effects on durability and fuel efficiency could not be completely eliminated.

The present invention has been made in view of such circumstances, and further improves the line pressure control during a shift transition by considering the primary pressure oil pressure at which belt slip actually occurs. As a result, the durability of the power transmission member (eg, belt)
An object of the present invention is to provide a control device for a continuously variable transmission that can surely eliminate deterioration in fuel efficiency and the like.

[0009]

Therefore, according to the present invention, as shown in FIG. 1, a driving-side rotating member for receiving the rotational force of a power source, a driven-side rotating member, A power transmission member interposed therebetween and transmitting power between the two, and 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; The driven-side rotating member and the driven-side by changing the driven-side contact rotating radius, which is the distance from the rotation center of the contact position between the driven-side rotating member and the power transmission member, steplessly. A control device for a continuously variable transmission configured to be able to set a speed ratio between a rotary member and a steplessly,
A drive-side fluid pressure target value setting means for setting a target value of the driving-side fluid pressure for controlling the drive side contact radius of rotation, driving the object
A driven fluid pressure target value setting means for setting a driven fluid pressure target value for controlling a moving contact rotation radius; and the driven fluid pressure target value setting means for setting the driven fluid pressure target value. Pressure control means for controlling to the set target value, and using the driven fluid pressure controlled by the pressure control means as a source pressure, the drive fluid pressure via the flow control valve to the drive fluid pressure target. and flow control means for controlling the set target value by the value setting means based on the target value of the driving-side fluid pressure at the time of shifting, the corrected target value set by the driven-side fluid pressure target value setting means , When shifting
Speed- change target value correction means for setting a target value of the driven-side fluid pressure, and control of the driven-side fluid pressure by the pressure control means so that the target value is corrected by the shift-time target value correction means. And a shift-time pressure control correcting means for correcting the pressure change.

According to the above configuration, for example, while the target value of the drive fluid pressure (hereinafter, also referred to as the shift pressure, the primary pressure) required to achieve the target speed ratio and prevent the belt from slipping is calculated. Since the driven fluid pressure (hereinafter, also referred to as line pressure) is corrected so as to actually achieve the target value, the drive fluid pressure at which the belt slips actually occurs is taken into consideration. As a result, the driven fluid pressure (line pressure) at the time of shifting is controlled, so that slippage of the power transmission member (eg, belt) can be reliably prevented, and the durability and the like of the belt are not impaired. There is no increase in rotational friction due to excessive tension), and furthermore, by suppressing unnecessary work of the oil pump, it is possible to reliably prevent deterioration of fuel efficiency and the like.

In addition, since it is not necessary to perform a complicated operation such as setting a correction amount during a shift transition for a plurality of parameters as in the related art, the number of man-hours for development and experiment can be greatly reduced. As a result, it is possible to reduce the product cost. According to the second aspect of the present invention, the target value correction means at the time of shifting is controlled by the driven fluid pressure in accordance with a ratio or deviation between an actual drive fluid pressure and a target value of the drive fluid pressure. The target value set by the target value setting means is corrected.

[0012] According to 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 (gear pressure) and the target value. Can compensate for product variations, and can more reliably prevent slippage of power transmission members (for example, belts), and do not impair belt durability (rotation friction due to excessive tension). In addition, by suppressing unnecessary work of the oil pump, it is possible to surely prevent deterioration of fuel efficiency and the like.

According to a third aspect of the present invention, the shift target value correction means calculates a time differential value of a ratio or a deviation between an actual driving fluid pressure and a target value of the driving fluid pressure. In addition, as the calculated time differential value is larger, the processing means includes a lead processing means for correcting the target value set by the driven fluid pressure target value setting means to a larger value.

With this arrangement, when the difference between the actual drive-side fluid pressure and the actual value of the drive-side fluid pressure is likely to increase due to a change in the target value of the drive-side fluid pressure or the like, 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 a delay in 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 the actual drive-side fluid pressure is decreasing), the greater the degree of the deviation (decrease tendency), the greater the driven-side fluid pressure. Is greatly changed (increased), so that a delay in the control system can be prevented, thereby reducing the response of the driven fluid pressure (line pressure) control, undershoot / overshoot of the driven fluid pressure, and the like. Can be suppressed as much as possible, whereby the belt slip can be more reliably prevented and the fuel efficiency can be reduced.

According to the fourth aspect of the present invention, the driving-side rotating member is a pulley whose effective winding radius can be changed,
The driven 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.

By adopting a so-called movable pulley type continuously variable transmission which is actually used for a vehicle or the like, it is advantageous in terms of cost reduction, commonality of parts, durability, maintenance and the like. It will be.

[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 shift transition, and the durability of the continuously variable transmission is not impaired. An increase in rotational friction can be suppressed, and a necessary and sufficient line pressure can be supplied without deteriorating fuel consumption due to oil pump loss or the like, thereby providing a good control device for a continuously variable transmission. .

According to the second aspect of the present invention, 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 and the target value. Since the value can be corrected, it is possible to cope with product variations and the like, and it is possible to more reliably prevent slippage of the power transmission member, and without impairing the durability of the belt (increase in rotational friction due to excessive tension). Further, by suppressing unnecessary work of the oil pump, it is possible to reliably prevent fuel consumption and the like from deteriorating.

According to the third aspect of the present invention, it is possible to prevent a delay in the control system at the time of shift transition, thereby reducing the responsiveness of the driven fluid pressure (line pressure) control and reducing the response of the driven fluid pressure. The occurrence of undershoots, overshoots, and the like can be suppressed as much as possible, so that belt slip can be more reliably prevented and fuel consumption can be reduced. According to the invention as set forth in claim 4, by employing a so-called movable pulley type continuously variable transmission which is actually employed for a vehicle or the like, cost reduction, component sharing, 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 (diff) side, and rubber or metal wound between them, or a combination thereof. The belt 6 is formed by adjusting the shift pressure to the primary pulley-side actuator 4a (shift-control hydraulic chamber) and the line pressure to the secondary pulley-side actuator 5a (tension control hydraulic chamber). By changing the effective pulley-side belt winding 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 driving-side rotating member that receives the torque of the power source, a driven-side rotating member, and a power transmission member 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. Stepless speed change ratio between the driving side rotating member and the driven side rotating member can be set steplessly by changing the driven side contact rotation radius relative to the driving side steplessly. Machine. 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 transmitting member and the winding conductive medium.

The drive-side fluid pressure for controlling the drive-side contact rotation radius according to the present invention corresponds to the shift pressure (primary pressure) in the present embodiment. Further, the driven fluid pressure for controlling the driven contact radius of rotation according to the present invention corresponds to the line pressure in the present embodiment. Here, the line pressure is controlled by the hydraulic circuit 8 connected to the oil pump 7.
The hydraulic pressure in the hydraulic path provided inside is controlled by opening and closing (for example, duty control) an electromagnetic valve (line pressure solenoid valve) 9 having a relief function, and the shift pressure is controlled. The flow pressure is controlled by adjusting the opening of the flow control valve 17 via the opening and closing drive of the solenoid valve 10 and the pressure is adjusted using the line pressure as the original pressure, and the drive control of these valves is controlled by a controller. 11 is controlled. The solenoid valve 9
Correspond to the hardware part of the pressure control means according to the present invention, and the solenoid valve 10 and the flow control valve 17 correspond to the hardware part of the flow 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 control valve 17 so that the required gear ratio can be achieved in accordance with the running conditions and the like. Thus, the gear ratio is controlled to a target value. A start 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 a solenoid valve 16, which is also controlled by the controller 11.

As will be described below, the controller 11 comprises a drive-side fluid pressure target value setting means, a driven-side fluid pressure target value setting means, a pressure control means,
Software functions are provided as flow rate control means, shift target value correction means, and shift pressure control correction means.
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) The input-side rotation sensor 12 that generates a pulse signal in synchronization with the rotation of the continuously variable transmission 3 generates a pulse signal in synchronization with the rotation of the output side (secondary pulley 5) in order to detect the actual output rotation number No of the continuously variable transmission 3. Output side rotation sensor 13, opening of throttle valve 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, a shift control routine performed by the controller 11 in the present embodiment will be described with reference to a control block diagram of FIG. This control is executed every predetermined unit time. First, block (1) [in the figure, B
It is described as (1). In the following, the target pressure (Ppmin) of the shift pressure (primary pressure) to be supplied to the primary pulley-side actuator 4a (the gear ratio control hydraulic chamber) is calculated. That is, the required minimum pressure (Ppmin) of the shift pressure (primary pressure) at which the belt 6 does not slip and the target shift ratio can be achieved, 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
Marked as 1. The same applies to the following), in order to determine the actual speed ratio (the speed ratio indicated by the controller 11 and the like) and the required minimum pressure (Ppmin) of the speed change pressure corresponding to the engine torque,
First, the required minimum primary pressure (gear pressure) ratio (θ ₁ / θ) for each gear ratio with respect to gear ratio = 1 is determined by the engine torque (or the input torque to the continuously variable transmission 3) and the required minimum. It is determined by referring to a map or the like set based on the relationship with the primary pressure. In the controller 11, the gear ratio is determined by the vehicle speed VSP and the throttle opening TVO.
The speed ratio is set based on the actual VSP, TVO, and the like by referring to a map or the like in which the speed ratio is determined based on the above. 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, it is possible to maintain the engine operating state with good fuel efficiency and exhaust performance.
It can be advantageous in exhaust performance and the like.

Then, in step 2, a 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. The shift target pressure (primary target pressure) (Ppmin) can also take into account the centrifugal oil pressure generated in the primary pulley-side actuator 4a. Next, in block (2),
Obtain the basic line pressure (Plprs st).

That is, the finally output line pressure (Pl
prs (this will be described later) is based on a supply line pressure (basic line pressure) and a transient correction coefficient (GainPL; this will be described later) for preventing the belt 6 from slipping during a shift transition. Because it is determined
As a basis for obtaining a final line pressure (Plprs), first, a basic line pressure (Plprs st) is calculated.

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

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

Accordingly, in this case, 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 that the belt does not slip and a desired gear ratio can be obtained. Thrust (F
Since P) can be determined, the required secondary thrust (FS) is obtained 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) = Primary minimum pressure (Ppmi
n) × area of primary pulley side movable wall 4A × coefficient 0−
Engine torque × coefficient 1 Note that coefficients 0 and 1 are coefficients determined by the gear ratio. Then, based on the required secondary thrust (FS), the required pressure on the secondary pulley (basic line pressure (Plprs st)) necessary to achieve a desired gear ratio without causing the belt 6 to slip on the primary pulley. ] Is calculated.

Specifically, the 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 movable wall 5A housed in secondary pulley side actuator 5a against line pressure. (Not shown). The basic line pressure (Plprs st) can also take into account the centrifugal hydraulic pressure generated in the secondary pulley-side actuator 5a.

The shift target pressure (primary target pressure) (Ppmin) and the basic line pressure (Plprs st) can also 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,) of 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 is not a ratio but may be a deviation between a target shift pressure (Ppmin) and an actual primary pressure (Ppsen).

The actual primary pressure (Ppsen) may be detected by a hydraulic pressure sensor or may be calculated. As a method of calculating the actual primary pressure (Ppsen) by calculation, for example, there is a method proposed by the present applicant in Japanese Patent Application No. 8-27161. According to this method, an opening area ratio Ar, which is a ratio between an opening area of an inflow portion and an opening area of an outflow portion of a spool valve (flow control valve 17), and a line pressure (PL; May be)
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)
InPP is multiplied by a correction coefficient KGPP to calculate a line pressure correction coefficient (GainPL) during a shift transition. That is, a process of GainPL = GainPP × KGPP is performed.

Note that GainPP (= Ppmin / Ppsen × K)
Is the minimum pressure (Ppmi) that is the target value of the primary (shift) pressure.
n) and the actual primary pressure (Ppsen) are set based on the ratio (or deviation) of the primary pressure (Ppsen) to achieve the target minimum primary pressure (Ppmin) for preventing the occurrence of belt slip. This is because the degree of influence on the change in the speed ratio when the line pressure is controlled by changing the duty ratio of the solenoid valve 9 is considered.

That is, the target minimum primary pressure (Ppmin)
When the line pressure is changed to achieve the above, 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 the target value. (Or control so that the actual line pressure becomes the target line pressure) in such a manner as to perform feedback control of the line pressure (control performed separately from the line pressure correction control during the shift transition), and the like. There is a concern that good control cannot be performed due to interference with the correction control (for example, control hunting). However, as described above, the target minimum primary pressure (Ppmi
If the degree of change in the line pressure when trying to achieve n) is taken into account, it is possible to suppress the occurrence of fears such as the control hunting.

If the configuration for controlling the line pressure [the configuration for controlling the transmission pressure (primary pressure) by controlling the original line pressure] as in the present embodiment, the winding diameter of both pulleys is reduced. Since it changes in the same direction, that is, if the winding diameter increases, both pulleys change in the increasing direction, so that a large change in the gear ratio does not occur, and the belt slip can be easily suppressed by a slight increase in the line pressure. For example,
Higher control accuracy and lower cost compared to a case where the shift pressure is controlled to a target pressure based on a detection signal from a shift pressure sensor or the like via the solenoid valve 10 (and, consequently, the flow control valve 17). And so on.

The line pressure correction coefficient (GainPL) at the time of shift transition is set during a downshift according to the flowchart shown in FIG. Value). That is, in step 31,
For example, the current set speed ratio (target speed ratio) Nexti is compared with a steady-state speed ratio (final target speed ratio) Basei, which is the final target, to determine whether a downshift is in progress.

If YES, a 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) during the shift transition. Therefore, the process proceeds to step 32, and as described above, the line pressure correction coefficient during the shift transition (GainPL) ) Is set to a predetermined value, and the process proceeds to block (5) described later. If NO, the downshift has been completed, it is determined that belt slip does not occur, and the routine proceeds to step 33, where the line pressure correction coefficient at the time of shift transition (GainPL) = 1.0 Then, GainPL is subtracted at a predetermined decrease rate, and the process proceeds to block (5) described later.

In this manner, belt slip at the time of downshift can be reliably suppressed with good responsiveness, and at the end of downshift, a steady state can be smoothly performed while suppressing a speed ratio shock or the like caused by a sudden change in line pressure. It is possible to shift to. Then, in block (5), the line pressure correction coefficient GainPL at the time of shift transition obtained in block (4).
And read the basic line pressure (Pl
prs st) is multiplied by this to obtain the final output line pressure (Plprs).

That is, a process of Plprs = Plprs st × GainPL is performed. In the next block (6), the actual line pressure from the line pressure sensor (calculation result from Prssen, duty ratio, etc.), the final output line pressure (Plprs) obtained in block (5), Of error (Errpl).

In the following block (7), the deviation (Errp
l) The duty ratio of the solenoid valve 9 for controlling the line pressure is corrected by PI (proportional integration) control or the like so as to eliminate l).
The duty signal (Plduty) is output to the solenoid valve 9.
Note that an upper limit value may be provided for the final duty signal (Plduty). That is, the output line pressure is
The hydraulic circuit 8 restricts the pressure to a predetermined pressure (upper limit hydraulic pressure) from a functional and structural aspect. Thereby, for example, abnormal increase of friction due to excessive increase of belt tension (when it becomes difficult to rotate), breakage of belt 6, damage of secondary pulley side actuator 5a and line pressure supply path, excessive drive of oil pump, etc. Can be prevented. Further, it is possible to prevent the occurrence of control failure due to an arithmetic error or the like.

As described above, according to the first embodiment,
While calculating the target shift pressure (primary pressure, Ppmin) necessary to achieve the target gear ratio and prevent the belt 6 from slipping, the target shift pressure (primary pressure, Ppmin) is calculated.
Actual primary pressure (Ppse
n) and the minimum required target shift pressure (primary pressure, Ppmi
n) and the line pressure is corrected to increase based on the ratio (or deviation) of the line pressure, that is, the line pressure control at the time of the shift transition is performed in consideration of the oil pressure of the primary pressure at which the belt actually slips. The power transmission member (eg, belt) can be reliably prevented from slipping, the durability of the belt is not impaired (no increase in rotational friction due to excessive tension), and the oil pump By suppressing unnecessary work, it is possible to reliably prevent deterioration of fuel efficiency and the like.

Further, the coefficient K and the correction coefficient KG can be obtained without performing a complicated operation such as setting a correction amount during a shift transition for a plurality of parameters as in the related art.
By simply changing the setting of PP, etc., it is possible to reliably suppress belt slips and reduce fuel consumption, so that development and experimental man-hours can be significantly reduced, and product costs can also be reduced. It becomes 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, a delay in the control system can be suppressed by performing a process to advance the line pressure correction coefficient (GainPL) at the time of shifting. It was done. Specifically, as shown in the control block diagram of FIG. 8, new blocks (8), (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 unit according to the present invention, and the controller 11 has its function as software.

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

That is, KDGPP = ΔGainPP / Δt (= Dl
tGPP) × KD Then, in block (10), block (3) similar to that of the first embodiment is used.
The advance processing correction value KDGPP obtained in the block (9) is added to the line pressure correction coefficient GainPL at the time of shift transition obtained at the step (1), and the final line pressure correction coefficient GainPL at the time of shift transition is obtained.
Set.

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

After that, as in the first embodiment, the process proceeds to block (5), where the line pressure correction coefficient GainPL at the time of the shift transition obtained in block (10) is read, and the basic value obtained in block (2) is obtained. The final output line pressure (Plprs =) is obtained by multiplying the line pressure (Plprs st) by this, and the subsequent blocks (6) and (7) are executed.
As described above, according to the second embodiment, the advance processing correction value KDGPP is calculated as GainPP [= Ppmin / Ppsen × K,
Alternatively, (Ppmin−Ppsen) × K may be used), so that the primary pressure (Ppmin) of the primary (shift) pressure changes and the actual primary pressure (Ppsen) is changed.
) Is likely to increase, the line pressure can be advanced and corrected with high responsiveness (in other words, according to the magnitude of the deviation) so as to suppress this difference. Therefore, it is possible to suppress the occurrence of a decrease in the response of the line pressure control and the undershoot / 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. . In other words, when the actual primary pressure has a deviation from the target primary pressure (for example, when it is decreasing), the line pressure changes (increases) more as the degree of the deviation (decreasing tendency) increases. As a result, delays in the control system can be prevented, thereby reducing the response of the line pressure control and the occurrence of undershoot and overshoot of the line pressure as much as possible. Thus, prevention and reduction of fuel consumption can be achieved.

The present invention can be applied to a system for controlling the increase and decrease of the line pressure so that a target shift pressure (primary pressure) can be obtained at the time of gear shifting. It is not limited. Further, the present invention 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 another setting method and purpose. 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 applied to the line pressure control. Even if it is reflected, the effect of the present invention is of course obtained. That is, instead of detecting the actual primary pressure, the steady-state line pressure may be corrected based on the target primary pressure during shifting.

In each of the above embodiments, the line pressure correction amount during the shift transition is given as the correction coefficient GainPL (that is, Plprs = Plprs st × GainPL), but the basic line pressure (Plprs st) Needless to say, the line pressure correction amount (absolute amount) during the shift transition may be added or subtracted. In each of the above embodiments, the power source is described as an engine. However, the present invention can be applied to a case where another power source is used.

[Brief description of the 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 of the 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 a 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 the setting of a line pressure correction coefficient (GainPL) during a shift transition.

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

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

[Explanation of symbols]

 Reference Signs List 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 rotation sensor 13 output rotation sensor 14 Throttle sensor 17 Flow control valve

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48 F16H 9/00

Claims (4)

(57) [Claims] A driving-side rotating member for receiving a rotating force of a power source; a driven-side rotating member; and a power transmitting member interposed between the driven-side rotating member and transmitting power between the two. A drive-side contact rotation radius that is a distance from a rotation center of a contact position between a rotating member and the power transmission member, and a driven-side rotation radius that is a distance from a rotation center of a contact position between the driven rotation member and the power transmission member. Control of a continuously variable transmission in which a gear ratio between the driving-side rotating member and the driven-side rotating member can be set in a stepless manner by changing a driving-side contact rotating radius and a stepless relative change. an apparatus, a drive-side fluid pressure target value setting means for setting a target value of the driving-side fluid pressure for controlling the drive side contact radius of rotation, the driven-side fluid pressure for controlling the driven side contact radius of rotation Driven fluid pressure target value setting means for setting a target value A pressure control means for controlling the driven fluid pressure to a target value set by the driven fluid pressure target value setting means, and a driven fluid pressure controlled by the pressure control means as an original pressure. Via the flow control valve, the drive side fluid pressure,
A flow rate control means for controlling to a target value set by the drive fluid pressure target value setting means; and a flow rate control means for setting the driven fluid pressure target value based on a target value of the drive fluid pressure at the time of shifting. The target value of the driven fluid pressure at the time of shifting is corrected.
A shift-time target value correction means for setting the shift-time target value correction means, and a shift-time pressure control correction for correcting the control of the driven fluid pressure by the pressure control means so that the target value is corrected by the shift time target value correction means. A control device for a continuously variable transmission, comprising: 2. A target fluid pressure target value setting means according to a ratio or deviation between an actual drive fluid pressure and a target value of the drive fluid pressure. 2. The control device for a continuously variable transmission according to claim 1, wherein the control device is means for correcting the target value set by (1). 3. The target value correction means at the time of shifting includes: an actual drive-side fluid pressure; a target value of the drive-side fluid pressure;
A time differential value of the ratio or deviation of the driven fluid pressure target value set by the driven side fluid pressure target value setting means as the calculated time differential value is larger. 2. The method according to claim 1, wherein
A control device for a continuously variable transmission according to claim 2. 4. The driving-side rotating member is a pulley whose effective winding radius is changeable, the driven-side rotating member is a pulley whose effective winding radius is changeable, and the power transmission member is a pulley whose effective winding radius is changeable. The control device for a continuously variable transmission according to any one of claims 1 to 3, wherein the control device is a winding conductive medium to be wound.