JP3367565B2 - Shift control method for continuously variable transmission - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously variable transmission.
The control method is particularly suitable for the driving operation and the running condition of the vehicle.
Shift Control Method for Continuously Variable Transmission that Can Perform Improved Shift Control
About the law. [0002] In a vehicle, between an internal combustion engine and driving wheels
A transmission is interposed. This transmission varies widely
Driving force of the drive wheels to match the driving conditions of the vehicle
Change the speed and make full use of the internal combustion engine.
You. The transmission includes, for example, a fixed pulley fixed to a rotating shaft.
Part and the fixed pulley part attached to the rotating shaft
Between the two pulley parts of the pulley having the movable pulley part
By increasing or decreasing the width of the groove formed in the
To reduce or increase the radius of rotation of the belt
Continuously variable transmission that changes the belt ratio (speed ratio)
There is. [0003] The continuously variable transmission is operated by hydraulic pressure.
Some have a hydraulic clutch that interrupts the force. This oil
The pressure clutch controls the engine speed and the carburetor throttle valve opening.
Control is performed in various control modes based on the signals. As the continuously variable transmission, for example, a transient
Determine the final target engine speed by making corrections.
The actual engine speed should be adjusted to match the final target engine speed.
If there is one that controls rate limit of gin rotation speed
Normally, when the throttle opening suddenly increases or when shifting
Perform rate limit control with a value larger than the control value
There are also things. For example, Japanese Patent Application Laid-Open No. 2-150556
There is one disclosed in Japanese Unexamined Patent Publication No. 60-88259. Further, Japanese Patent Publication No. 4-28947 and Japanese Patent Application Laid-Open
There is one disclosed in Japanese Patent Application Laid-Open No. 4-165162. Special
What is disclosed in JP-A-4-165162,
Actual engine speed and steady state target engine speed
Calculate the target change speed of the engine speed from the difference with the speed.
The speed ratio change speed as a control value
The target change speed of the rotation speed is
Corrected according to the target change speed. This gazette and this application
If the differences from the above are described for reference,
Set the target change speed of the engine speed to the current engine speed.
While the rotation speed is corrected by the target change speed,
Thus, the invention of the present application provides a target change speed of the engine rotational speed.
Engine based on the degree and the accumulated data of the previous target change rate
The target change speed of the rotation speed is set. That is,
The target change speed of the engine rotation speed is set to A and
Assuming that the accumulated data of the target change speed of B is B,
The target change speed A of the engine rotation speed is set by A = α + ΣB or A = α-ΣB. [0006] By the way, the above-mentioned conventional
Japanese Patent Laid-Open No. 2-150556 discloses a continuously variable
In the speed change control method for the high speed machine, the setting of the limit value is performed.
The driving operation is performed in accordance with the turning operation and the running state of the vehicle.
In addition to determining from the rottle operation and shift operation,
The running state is determined from the vehicle speed. However, the method described in the above publication is
If the limit value is set by
Is caused. In other words, a moderate engine brake
Drive wheel slip on situations where it is necessary or on slippery road surfaces
In the actual driving situation where the actual engine speed changes due to
Throttle indicating driver's driving operation and vehicle running state
Set limit values based on changes in opening and throttle opening and vehicle speed
If you try to do so, each of these parameters will
Sometimes it cannot be reflected accurately. Therefore, driver's driving
To set limit values suitable for operation and vehicle running conditions
Has complex tuning work, complex control of control means
Program is required. Further, in the speed change control by the control means,
The actual engine speed (NE)
Target engine speed (NESPR)
Control the actual engine speed (NE)
And the steady state target engine speed (NESPR)
When the vehicle speed is high despite the large difference (ERR)
Has a small limit value for the amount of change in transient correction.
The steady state target of the actual engine speed (NE)
Possibility to follow engine speed (NESPR)
In addition, there is a disadvantage that it is practically disadvantageous. Accordingly, the present invention provides
In order to eliminate the inconvenience, the fixed pulley
With the movable pulley part attached to the pulley part
Increase or decrease the groove width between both pulley parts by hydraulic pressure
Increase or decrease the radius of rotation of the belt wound around
The engine speed must be changed between the throttle opening and the vehicle speed.
Steady state target engine speed obtained from Joule map
To the final target engine speed after transient correction
Shift control method of continuously variable transmission that controls shift to match
The target engine speed and the actual engine speed.
The limit value is set according to the difference from the
The limit value is increased to a predetermined value according to the increase in the difference.
And the amount of change in the final target engine speed is controlled
Limit the final target engine speed so as not to exceed the limit
Actual energy to the limited final target engine speed.
The gear shifting control is performed to match the engine rotation speed.
Sign. According to the invention described above, the target engine
Limited according to the difference between engine speed and actual engine speed
Set the value and set the limit value as the difference increases
To the final target engine speed.
Target engine speed so that the amount of change does not exceed the limit
Limit speed to limited final target engine speed
Shift control to match the actual engine speed,
Performs gear shifting control suitable for driving operation and vehicle running conditions
ing. An embodiment of the present invention will be described below in detail with reference to the drawings.
Will be described. 1 to 11 show an embodiment of the present invention.
It is. In FIG. 2, 2 is a continuously variable transmission, and 4 is
, 6 is a drive side pulley, 8 is a drive side fixed pulley piece,
10 is a drive side movable pulley piece, 12 is a driven side pulley,
14 is a driven side fixed pulley piece, and 16 is a driven side movable pulley.
It is a part piece. The driving pulley 6 is provided as shown in FIG.
Drive-side fixed to a rotating shaft 18 rotated by a prime mover.
The constant pulley piece 8 is movable in the axial direction of the rotating shaft 18 and
A drive-side movable pulley attached to the rotating shaft 18 so that it cannot rotate.
And a re-piece 10. In addition, the driven pulley 12
Has a structure similar to that of the driving pulley 6 and is fixed on the driven side.
It has a pulley piece 14 and a driven-side movable pulley piece 16
You. The movable side pulley piece 10 and the driven side
The first and second housings 20 are attached to the movable pulley piece 16.
22 are respectively mounted on the first and second hydraulic chambers 2.
4 and 26 are respectively formed. The second hydraulic chamber 26 on the driven side
Inside the driven side movable pulley piece 16
Pressing spring 28 biasing to approach tool piece 14
Is provided. An oil pump is provided at the end of the rotating shaft 18.
30 are provided. This oil pump 30 is
The oil of Lupine 32 is passed through an oil filter 34,
First and second oil passages 38 and 40 constituting the pressure circuit 36
To feed the first and second hydraulic chambers 24 and 26
It is. In the middle of the first oil passage 38, the input shaft sheave
The pressure control means 42 is configured to control the primary pressure.
A primary pressure control valve 44, which is a speed change control valve, is provided.
It is. In addition, the oil pressure pump is
The third oil passage communicating with the first oil passage 38 on the side of the pump 30
Line 46 has a line pressure (generally 5-25 ° / 〓). ^Two One)
Constant pressure (for example, 3-4〓 / 〓 ^Two ) Constant pressure control valve 4
8 are provided. Further, the primary pressure control valve 44 includes:
The first pressure control first through the fourth oil passage 50
A three-way solenoid valve 52 is provided in series. In the middle of the second oil passage 40,
LA with a relief valve function to control the line pressure as the pump pressure
An in-pressure control valve 54 is connected through a fifth oil passage 56.
It is. The line pressure control valve 54 is connected via a sixth oil passage 58
And is connected to the second three-way solenoid valve 60 for line pressure control.
You. Further, the line pressure control valve 54 communicates with the line pressure control valve 54.
In the second oil passage 40 on the second hydraulic chamber 26 side of the part
Is provided with a clutch pressure control valve 62 for controlling the clutch pressure.
The fifth oil passage 56 is provided using the branched other end.
Have been. The clutch pressure control valve 62 has an eighth oil
A third three-way solenoid valve 68 for controlling the clutch pressure through a passage 66
To communicate. Further, the primary pressure control valve 44 and the
The primary solenoid valve 52 for primary pressure control, the constant pressure control valve 48,
In-pressure control valve 54, second three-way solenoid valve 6 for line pressure control
0, clutch pressure control valve 62, and clutch pressure control valve
The three-way solenoid valves 68 are respectively connected by ninth oil passages 70.
Communicating. The clutch pressure control valve 62 is provided with a seventh oil
Hydraulic pressure via a tenth oil passage 72 communicating with the passage 64
The clutch 74 is in contact. This tenth oil passage 7
In the middle of the pressure transducer, an eleventh oil passage 76
78. This pressure transducer 78 is held
And when controlling the clutch pressure in the start mode, etc.
The oil pressure can be detected directly, and the detected oil pressure
It has a function to command to set the latch pressure, and
Clutch mode becomes almost equal to line pressure
Therefore, it also contributes to line pressure control. The hydraulic clutch 74 includes a piston 80,
Annular spring 82, first pressure plate 84, friction
And a second pressure plate 88, etc.
Have been. A slot of a carburetor (not shown) of the vehicle
Input various conditions such as the opening of the
Electronic control unit that changes gear ratio and controls gear shifting
A control means (ECU) 90 is provided.
The first three-way solenoid valve 52 for primary pressure control
Second three-way solenoid valve 60 for line pressure control, and clutch pressure
When the opening and closing operation of the control third three-way solenoid valve 68 is controlled,
In addition, the pressure transducer 78 is also configured to be controlled.
ing. Various signals input to the control means 90
In detail, the function of the input signal is as follows. The detection signal of the shift lever position...
Line pressure, belt ratio, clutch
Control, carburetor throttle opening detection signal ...
Gin torque is detected and the target belt ratio or target
The engine speed is determined, and the carburetor idle position detection signal is used for correcting and controlling the carburetor throttle opening sensor.
Accelerator pedal signal ... The driver's will depends on the accelerator pedal depressed state
To determine the control direction at the time of running or starting, and a brake signal.
Determines control method such as switch release, power mode option signal ..... Sports (or economy) performance of vehicle
There is an option to use it. The control means 90 controls the target engine speed.
Limit value according to the difference between the engine speed and the actual engine speed.
And the limit value will be up to the specified value as the difference increases.
Set to increase and change in final target engine speed
The final target engine speed so that the amount does not exceed the limit.
Limit and limit the actual target engine speed to
Speed change control to match the engine speed
is there. The control means 90 has a configuration as shown in FIG.
To obtain the final target engine speed (NESPRF).
It is. As shown in FIG. 3, the throttle opening (TH
R) and vehicle speed (NCO) values and shift operation
The steady state target engine speed (NESPR)
It is set (201). The set target engine speed (NES)
PR) is a transient repair depending on the driving operation and the running condition of the vehicle.
Correction is made (202), and the final target
Gin rotation speed (NESPRF). Then, the actual engine speed (NE)
Target transient engine speed (NES)
(PRF), and adjust the gear ratio to match the engine speed.
Control, that is, gear shift control. That is, the final target engine speed (N
ESPRF) is based on PI control (203) and integration
After the anti-slip (204)
It changes based on the neutral value Un of the solenoid duty Ur.
By adjusting the ratio solenoid duty Ur that becomes the speed ratio
I have. The target engine speed (NESPR)
The throttle opening (THR) as a factor
From the map (RACRVT) (see FIG. 5)
Engine speed (NESP) with respect to throttle opening (THR)
RT) and the vehicle speed (NCO) as a factor
Map (RACRVH, RACRVL) (see Fig. 6)
Engine speed with respect to throttle opening (THR)
Upper limit (NESPRH) and lower limit of (NESPRT)
(NESPRL) and the throttle opening (THR)
Engine speed (NESPRT) and upper limit value
(NESPRH) and lower limit (NESPRL)
By limiting the target engine speed (NESPR)
The settings are made. The throttle opening (THR) is a factor.
Map (RACRVT) and vehicle speed (NCO) as factors
Map (RACRVH, RACRVL)
The same throttle opening (T
HR) and vehicle speed (NCO)
If the target engine speed (NESP)
R) are different. Further, the target engine speed (NESP)
R), the transient correction is performed as shown in FIG.
Filter (301) the speed (NESPR),
The processing value is set to NESPF, and the maximum
Controls the amount of change in the final target engine speed (NESPRF)
Limit value, that is, the final target engine speed per unit time
(NESPRF) upper and lower limits of change (RATUP)
Rate limit control to limit with limit value (RATLO)
(302). In this rate limit control (302),
Is simply set by the driving operation and the running state of the vehicle.
Final target engine speed per unit time (NESPR
F) Lower limit of variation (RATLO) (303) and above
The limit value (RATUP) (304) is as apparent from FIG.
The last target engine speed (NESPR
F), that is, set in consideration of NESPRN. Also, the throttle opening is determined by the driving operation.
When (THR) suddenly increases or when performing a shift operation
Is the rate limit at a limit that is greater than the normal limit
Control (transient control). The control means 90 has the above-mentioned communication.
In addition to the normal control, the actual engine speed (NE)
Target engine speed ("target engine speed in steady state"
(Also called "degree") (NESPR)
The final target per unit time is calculated by this difference (ERR).
Upper limit of change in engine speed (NESPRF)
(RATUP) and the lower limit (RATLO) are set.
Final target engine times per unit time according to (ERR)
Upper limit (RATU) of the change amount of the rotation speed (NESPRF)
P) and the lower limit (RATLO) are changed respectively
Steady-state target engine speed of rotation speed (NE)
(NESPR) control to improve the followability
Noh is added. The final target engine per unit time
Upper limit value (RATU) of change amount of rotation speed (NESPRF)
P) and the lower limit (RATLO) are shown in FIG.
As described above, this is performed by the rate limit map. As shown in FIG. 2, the first housing
An input shaft rotation detection gear 102 is provided outside the
Near the outer peripheral portion of the input shaft rotation detection gear 102
Side first rotation detector 104 is provided. In addition, the
2 An output shaft rotation detection gear 106 is provided outside the housing 22.
Around the outer peripheral portion of the output shaft rotation detection gear 106.
Is provided with a second rotation detector 108 on the output shaft side. Said
Detection of first rotation detector 104 and second rotation detector 108
The signal is output to the control means 90 and the engine speed is
And the belt ratio. The power transmission gear 1 is connected to the hydraulic clutch 74.
10 near the outer peripheral portion of the output transmission gear 110.
A third rotation detector 11 for detecting the rotation of the final output shaft
2 are provided. That is, the third rotation detector 112
Is directly connected to reduction gears and differentials, drive shafts and tires
It detects the rotation of the final output shaft and detects the vehicle speed.
It is possible. In addition, the second rotation detector 10
8 and the third rotation detector 112, the hydraulic clutch 74
Rotation of the input shaft and output shaft of the
The slip amount can be detected. Next, the operation of this embodiment will be described.
You. The continuously variable transmission 2 is constructed as shown in FIG.
The oil pump 30 located on the rotating shaft 18 is
18 according to the rotation of the oil pan 32 and
Oil is sucked in through the oil filter 34. Po
The line pressure, which is the pump pressure, is controlled by the line pressure control valve 54
The amount of leakage from the line pressure control valve 54,
If the relief amount of the in-pressure control valve 54 is large, the line pressure is
The lower the pressure, the higher the line pressure. The operation of the line pressure control valve 54 is a dedicated
The second three-way solenoid valve is controlled by a two-three-way solenoid valve 60.
The line pressure control valve 54 operates following the operation of 60.
You. The second three-way solenoid valve 60 has a constant frequency duty ratio.
Is controlled by That is, the duty ratio of 0% corresponds to the second three-way
The magnetic valve 60 does not operate at all, and the output side is the atmosphere side.
And the output oil pressure becomes zero. Also, the duty ratio 10
0% means that the second three-way solenoid valve 60 operates and the output side is input.
And the maximum output oil pressure equal to the control pressure. One
That is, due to the change in the duty ratio to the second three-way solenoid valve 60,
Output hydraulic pressure. Therefore, the second three directions
The characteristic of the solenoid valve 60 is that the line pressure control valve 54 is
Operation of the second three-way solenoid valve 6
Line pressure is controlled by arbitrarily changing the duty ratio of 0
Can be The operation of the second three-way solenoid valve 60
Is controlled by the control means 90. The primary pressure for shifting control is the primary pressure.
This primary pressure control valve is controlled by a control valve 44
Similarly to the line pressure control valve 54, a dedicated first
The operation is controlled by the one-way solenoid valve 52. This first
The three-way solenoid valve 52 conducts the primary pressure to the line pressure.
To communicate the primary pressure to the atmosphere side
Used to conduct the belt pressure by conducting to the line pressure.
Move to the driver side or conduct to the atmosphere side
This is to shift to Le Roux side. Clutch pressure control valve 6 for controlling clutch pressure
2 communicates with the line pressure side when maximum clutch pressure is required.
At the minimum clutch pressure and communicate with the atmosphere side
It is to let. This clutch pressure control valve 62 is also
Like the in-pressure control valve 54 and the primary pressure control valve 44,
The operation is controlled by a dedicated third three-way solenoid valve 68.
Therefore, the description is omitted here. Clutch pressure is minimal
Changes from atmospheric pressure (zero) to maximum line pressure
Is what you do. For controlling the clutch pressure, for example, five
There is a turn. (1) Neutral mode: The shift position is N or P and the hydraulic clutch is completely disengaged
When disengaging, the clutch pressure is the minimum pressure (zero) (2), hold mode ... Driving with the throttle released when the shift position is D or R
If there is no will, or while driving,
If you want to release the clutch, make sure that the clutch pressure is
Low level (3), normal start mode ... Release the clutch when starting or after disengaging the clutch
When attempting to engage, increase the clutch pressure
This prevents the vehicle from moving and allows the vehicle to operate smoothly.
According to the engine generated torque (clutch input torque)
The appropriate level (4), special start mode ... (a), when the vehicle speed is 8〓 / H or higher, shift lever
N-> D repeated use, or (b),
During deceleration operation, brake at 8〓 / H <vehicle speed <15 ブ レ ー キ / H
(5), drive mode ..... Transit to complete running state and clutch fully engaged
If the clutch pressure is enough to withstand the engine torque
There are five high levels that can afford. The pattern (1) is linked with the shift operation.
It is performed by a switching valve (not shown) dedicated to
(2), (3), (4) and (5) are performed by the control means 90.
The first, second and third three-way solenoid valves 52, 60, 68
It is performed by the tee rate control. Especially the condition of (5)
In addition, the seventh oil passage is controlled by the clutch pressure control valve 62.
64 communicates with the tenth oil passage 72 to generate the maximum pressure.
State, and the clutch pressure becomes the same as the line pressure. The primary pressure control valve 44 and the line
Pressure control valve 54 and clutch pressure control valve 62
Outputs from the first, second and third three-way solenoid valves 52, 60 and 68
These are controlled by hydraulic pressure, respectively.
2, a controller for controlling the third three-way solenoid valves 52, 60, 68
The roll oil pressure is a constant oil pressure adjusted by the constant pressure control valve 48.
You. This control oil pressure is always lower than the line pressure
, But stable and constant pressure. In addition,
The control oil pressure is also introduced into each of the control valves 44, 54, 62,
These control valves 44, 54, 62 are stabilized. Next, the electronic control of the continuously variable transmission 2 will be described.
Will be explained. When the continuously variable transmission 2 is under hydraulic control,
In both cases, the belt holding and the
Appropriate line pressure for transmission of torque and transmission ratio (belt
Ratio) change of primary pressure and hydraulic
Clutch pressure is secured to secure the connection
Have been. Next, the target engine speed in the steady state shown in FIG.
A description will be given along a flowchart for setting the rotational speed. The setting program starts (401).
And a map (R) based on the throttle opening (THR) in FIG.
ACRVT) to throttle opening (THR)
Engine rotation speed (NESPRT)
Map (RACRVH, RA) based on the vehicle speed (NCO)
CRVL) to the throttle opening (THR)
Gin rotation speed (NESPRT) upper limit (NESPR
H) and the lower limit (NESPRL) are obtained (402).
Engine rotation speed (N
ESPRT) and throttle opening (THR)
Gin rotation speed (NESPRT) upper limit (NESPR
H) is compared (403). In this comparison judgment (403), the NES
If PRT <NESPRH, the throttle opening (T
HR) and engine speed (NESPRT)
Engine rotation speed (N
Comparison judgment with the lower limit (ESPRL) of ESPRT)
(404), and when NESPRT ≧ NESPRH
In case, engine rotation with respect to throttle (THR)
Speed (NESPRT) is the target engine speed in steady state
Degree (NESPR) (405) and move to end (408)
Let go. In the comparison judgment (404),
If NESPRT> NESPRL, the slot
Engine speed (NESP) with respect to throttle opening (THR)
RT) to the steady state target engine speed (NESP)
R) (406), and the process proceeds to the end (408).
If SPRT ≦ NESPRL, throttle opening
Engine speed (NESPRT) against (THR)
Target engine speed in steady state
Set the rotation speed (NESPR) (407) and end (408)
Move to For transient correction of target engine speed shown in FIG.
Description will be given along a flowchart. The steady state target engine speed (NES)
PR) transient correction program starts (501)
And the steady state target engine speed (NESPR)
Filter processing is performed to obtain NESPF (502). The final target engine per unit time
Upper limit value (RATU) of change amount of rotation speed (NESPRF)
P) and the lower limit (RATLO) are set (50
3). This setting process (503) is shown in FIG.
As described above, the setting flowchart starts (503A).
And the steady state target engine speed (NESPR)
Find the difference (ERR) from the actual engine speed (NE)
(503B), the rate limit map shown in FIG.
Target engine per unit time according to the difference (ERR)
Upper limit value (RAT) of the amount of change in rotation speed (NESPRF)
UP) and the lower limit (RATLO) are obtained (503C),
The process is shifted to end (503D). Next, the final target engine times per unit time
Upper limit (RATU) of the change amount of the rotation speed (NESPRF)
After setting (P) and lower limit (RATLO) (503)
The target steady state engine speed after filtering
(NESPF) and the last final target engine speed (N
ESPRN) is compared (504). Then, in the comparison judgment (504), NE is set.
If SPR <NESPRN, the last final target
Gin rotation speed (NESPRN)
Normal target engine speed (NESPF) was subtracted
Value and final target engine speed per unit time (NES
Judgment with the lower limit (RATLO) of the variation of PRF)
The process proceeds to (505). In the comparison judgment (504), the NES
When PR ≧ NESPRN, the steady state after filtering
From the target engine speed (NESPF)
Value obtained by subtracting the final target engine speed (NESPRN)
And the final target engine speed per unit time (NESP
RF) comparison with upper limit (RATUP)
The process proceeds to (506). In the above-mentioned comparison judgment (505), NE
If SPRN-NESPF> RATLO, NES
Set the value of PRN-RATLO to the final target engine speed.
(NESPRF) (507) and NESP
If RN-NESPF ≤ RATLO, filter processing
Steady state target engine speed (NESPF)
Is the final target engine speed (NESPRF)
(508). Also, in the comparison judgment (506) described above,
Therefore, if NESPF-NESPRN ≦ RATUP,
Is the steady-state target engine speed after filtering
(NESPF) to the final target engine speed (NESP)
RF) (508), and the NESPF-
If NESPRN> RATUP, the previous final goal
Maximum engine speed (NESPRN) per unit time
Above the change in the final target engine speed (NESPRF)
Limit value (RATUP) plus final target engine speed
The speed (NESPRF) is set (509). Then, each processing (507), (508),
(509) Final target engine speed (NESPR
F) to the last target engine speed (NESPR)
N) (510), and end (511). As a result, the target engine speed and the actual
If the limit value is set according to the difference between
In both cases, the limit value increases to a predetermined value as the difference increases
To limit the amount of change in the final target engine speed.
Limit the final target engine speed to not exceed the value,
Real engine at limited final target engine speed
Speed change control can be performed to match the rotational speeds.
Set a limit value suitable for the turning operation and the running state of the vehicle.
And improve drivability. The state of change in the engine generated torque is
It is practically advantageous because it can be easily reflected in speed changes.
You. Further, the normal P
Improves reliability of shift control by performing I control
Can be done. Further, a control program of the control means 90 is provided.
Program simplification,
Can save memory capacity and facilitate tuning operation
It is economically and practically advantageous. As described in detail above, according to the present invention,
If the target engine speed and the actual engine speed are
The limit value is set according to the difference between
Set to increase to a predetermined value as the increase
Final so that the amount of change in engine speed does not exceed the limit
Limit the target engine speed and limit the final target
Match the actual engine speed to the engine speed
Gear shift control, so that driving operation and vehicle running conditions
Drivability can be set to appropriate limits
And the changing state of the engine generated torque
Is easily reflected in changes in vehicle speed, which is practically advantageous. Ma
In addition, normal PI control is performed, so that shift control
Reliability can be improved. Furthermore, the program is simplified
Can save memory space and improve tuning.
Operation can be facilitated, economically and practically.
It is more advantageous.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (a) is a time chart of an actual engine speed (NE) showing an embodiment of the present invention. (B) A time chart of a difference (ERR) between an actual engine speed (NE) and a target engine speed (NESPR) in a steady state. (C) Final target engine speed per hour (NESP
7 is a time chart of an upper limit value (RATUP) of a change amount of the RF (RF) and a lower limit value (RATLO) of a change amount of a final target engine rotation speed per hour (NESPRF). FIG. 2 is a schematic diagram of a continuously variable transmission and a hydraulic circuit. FIG. 3 is a block diagram of a shift control loop. FIG. 4 is a block diagram of transient correction of a target engine rotation speed. FIG. 5 is a diagram showing a throttle opening (THR) and a target engine rotation speed (N) in a steady state based on the throttle opening (THR);
FIG. FIG. 6 is a diagram illustrating a relationship between a vehicle speed (NCO) and an upper limit value (NESPRH) and a lower limit value (NESPRL) of a target engine rotation speed (NESPR) in a steady state. FIG. 7 is a flowchart for setting a target engine rotational speed in a steady state. FIG. 8 is a time chart of a target engine rotation speed in a steady state. FIG. 9 is a flowchart for transient correction of a target engine rotational speed in a steady state. FIG. 10 is a flowchart for setting a rate limit. FIG. 11 is a rate limit map. DESCRIPTION OF THE SYMBOLS 2 Continuously variable transmission 4 Belt 6 Drive side pulley 12 Driven side pulley 18 Rotary shaft 30 Oil pump 38 First oil passage 40 Second oil passage 42 Pressure control valve means 44 Primary pressure control valve 46 Third Oil passage 48 Constant pressure control valve 50 Fourth oil passage 52 First three-way solenoid valve 54 for primary pressure control Line pressure control valve 56 Fifth oil passage 58 Sixth oil passage 60 Second three-way solenoid valve 62 for line pressure control Clutch pressure control Valve 64 Seventh oil passage 66 Eighth oil passage 68 Third three-way solenoid valve 70 for clutch pressure control 70th ninth oil passage 72 10th oil passage 74 Hydraulic clutch 76 11th oil passage 78 Pressure converter 90 Control means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI F16H 63:06 F16H 63:06 (56) References JP-A-2-150556 (JP, A) JP-A-60-88259 (JP) JP-A-1-275948 (JP, A) JP-A-4-165162 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48 B60K 41/00-41/28 F02D 29/00-29/06

Claims (1)

(57) [Claims 1] A groove width between a fixed pulley part and a movable pulley part attached to and detachable from the fixed pulley part is increased or decreased by hydraulic pressure. The rotation radius of the belt wound around the pulleys was reduced and the actual engine speed was transiently corrected to the steady-state target engine speed obtained from the shift schedule map of the throttle opening and the vehicle speed. In a shift control method for a continuously variable transmission that performs shift control so as to match a later final target engine rotation speed,
A limit value is set according to the difference between the target engine speed and the actual engine speed, and the limit value is
Set to increase to a predetermined value as the difference increases, and
The change amount of the final target engine speed does not exceed the limit value.
Limit the final target engine speed,
Actual engine speed to the final target engine speed
A shift control method for a continuously variable transmission, wherein the shift control is performed to match the degrees .