JP3094606B2 - Transmission 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 apparatus for controlling a speed of a transmission for continuously variable transmission by changing a winding diameter ratio of a belt wound around a pair of pulleys by a switching operation of a hydraulic actuator. the shift speed is calculated on the basis of a deviation between the actual speed ratio and the target speed ratio, it relates to a shift control device for a continuously variable transmission to perform continuously variable by changing the diameter ratio winding of the pulleys in the transmission rate.

[0002]

Conventionally, wound around the drive belt between the primary pulley and the secondary pulley, a continuously variable transmission of the belt drive to perform continuously variable by changing the diameter ratio winding belt that is wound around the pulleys Machines are known. The continuously variable transmission supplies a shift control oil pressure based on a gear ratio determined according to engine operation information to a spool of a gear ratio control valve, and each pulley control oil pressure adjusted based on a hydraulic pressure switching operation of the spool. Is supplied to both hydraulic actuators for operating the relative distance between the fixed pulley member and the movable pulley member of both the primary and secondary pulleys. Thus, the continuously variable transmission is performed by changing the winding diameter ratio of the belt wound around the pair of pulleys.

The speed ratio i of the continuously variable transmission is equal to the ratio i (= Wp / Ws) of the primary pulley rotational speed Wp and the secondary pulley rotational speed Ws. When this speed ratio i is corrected to a target value, control is performed. The means supplies each pulley control hydraulic pressure capable of achieving the target gear ratio to the hydraulic actuators of both the primary and secondary pulleys by using the shift control valve and the electromagnetic control valve. In this case, for example, as shown in FIG. 17, the conventional control means takes in the target primary pulley rotation speed Wpo and the actual primary pulley rotation speed Wp corresponding to the target gear ratio, and obtains a deviation E1 (= Wpo).
-Wp), and a change gain K1 for decreasing responsiveness as the engine speed increases and a change gain K for increasing responsiveness as the deviation between the actual value of the primary pulley and the target value increases.
2, the basic shift speed Vi1 is calculated by multiplying the deviation E1 by both gains K1 and K2, and the basic shift speed Vi1 is sequentially integrated to obtain an integral term ΣΔViI, which is multiplied by a limiter to obtain a correction coefficient 1 / The integral corrected shift speed ViI is obtained by multiplying Z. Then, the shift speed Vi is calculated by adding the basic shift speed Vi1 and the integral corrected shift speed ViI, and the electromagnetic control valve is driven by the shift speed signal Du corresponding to the shift speed control pressure Pc capable of achieving the shift speed Vi. Then, the electromagnetic control valve regulates the shift speed control pressure Pc, and the speed ratio control valve receiving the shift speed control pressure Pc supplies the respective pulley control oil pressures to the hydraulic actuators of both pulleys, and sets the two pulleys to the target speed ratio i. Is configured to be switched.

[0004]

By the way, as described above, the target primary pulley rotational speed Wp corresponding to the target gear ratio is obtained.
o and the deviation E1 (= Wp) between the actual primary pulley rotation speed Wp.
o-Wp) asking, in the case of adopting the processing only to multiply the gain K1, K2 for correcting the response obtained from the fixed map on a deviation E1 say seek basic shift speed Vi1, road surface during traveling of the vehicle Is not considered. For this reason, the vehicle drives on the road surface with a low friction coefficient μ.
If you produce a slip with the gear ratio is too large when the drive is there, it becomes possible to give the adverse effect on the degradation and operation feeling of the fuel consumption, and has a problem.

An object of the present invention is to provide a driving force against a road surface μ.
Reduce the gear ratio only when it becomes excessive, and slip the drive wheels.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a shift control device for a continuously variable transmission, which can suppress driving and improve driving feeling.

[0006]

In order to achieve the above-mentioned object, the present invention is mounted on a primary pulley and a secondary pulley on which a drive belt is wound, and the winding diameter ratio between the two pulleys is a predetermined speed ratio. A pair of hydraulic actuators for increasing and decreasing each pulley clearance so as to obtain a value corresponding to the above, a friction coefficient calculating means for calculating a friction coefficient of the traveling road surface, and a lower value is set as the allowable maximum speed ratio as the friction coefficient is lower. Maximum speed ratio setting means for performing the operation, target speed ratio calculating means for calculating a target speed ratio based on the specified target primary pulley speed and actual primary pulley speed, and setting the target speed ratio to the allowable maximum target speed ratio. Corrected target gear ratio calculating means for restricting and calculating a corrected target gear ratio, and deviation gear ratio calculating means for calculating a deviation gear ratio between the corrected target gear ratio and the actual gear ratio A shift speed calculating unit that calculates a shift speed based on the deviation shift ratio; and a shift drive unit that calculates a shift speed signal corresponding to the shift speed and drives an electromagnetic control valve. The pulley control oil pressure of the hydraulic actuator is adjusted to switch the two pulleys at a target speed.

[0007]

The allowable maximum speed ratio setting means sets a lower value as the road surface friction coefficient is lower as the allowable maximum speed ratio, and the corrected target speed ratio calculating means uses the corrected speed ratio from the target speed ratio calculating means as the allowable maximum speed ratio. The corrected target speed ratio is calculated, the deviation speed ratio calculating means calculates the deviation speed ratio between the corrected target speed ratio and the actual speed ratio, and the speed speed calculating means calculates the speed speed based on the deviation speed ratio. The shift drive means calculates a shift speed signal corresponding to the shift speed and drives the electromagnetic control valve. The electromagnetic control valve regulates the pulley control oil pressure of the hydraulic actuator to switch both pulleys at the target shift speed, so that the friction coefficient is increased. The lower the gear ratio, the smaller the gear ratio at the time of starting can be made.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The continuously variable transmission shown in FIG. 1 has a continuously variable transmission 2 on a power transmission system P connected to an engine 60 of a vehicle.
It is attached to 0. Here, the engine 60 is an electronically controlled fuel injection type four-cycle engine, such as an injector 1 for injecting fuel and a spark plug 2 for igniting an air-fuel mixture.
Various devices are DBWE as electronic control means of engine
It is placed under the control of CU3, and this DBWECU3
Is connected to a CVT ECU 21 which is an electronic control unit of a continuously variable transmission (CVT) 20 in the power transmission system P. The two ECUs 3 and 21 are connected by a communication line so that signals can be exchanged between the two ECUs 3 and 21 at all times.

The DBWECU 3 is connected to an actuator 11 for driving the throttle valve 9 as an intake air amount operating means which is driven independently of the operation of an accelerator pedal 10 as an artificial operating member. An electromagnetic control valve 23 that hydraulically controls the shift speed of the step transmission 20 is connected. Here, the overall configuration of the engine 60 will be briefly described. The flow rate of the intake air sucked from the air cleaner element 5 is measured by a Karman vortex airflow sensor 6 immediately after the intake air. In the air cleaner body 4, devices such as an atmospheric pressure sensor and an atmospheric temperature sensor (not shown) are provided in addition to the air flow sensor 6, and various data relating to the intake air are measured.
It has a well-known configuration in which it is input to the WECU 3.

The amount of intake air flowing into the throttle body 8 from the air cleaner body 4 through the intake pipe 7 is controlled by a butterfly type throttle valve 9. The throttle valve 9 is opened and closed by an actuator (in this embodiment, a step motor) 11, not by an accelerator pedal 10 depressed by the driver. In this embodiment,
A so-called DBW (drive-by-wire) system in which the actuator 11 is controlled by the DBWECU 3 is employed. In the figure, reference numeral 12 denotes a throttle position sensor (hereinafter, a throttle sensor) that outputs opening degree information of the throttle valve 9 as intake air amount information, and a detection signal thereof is input to the DBWECU 3.
The accelerator pedal 10 is provided with an accelerator opening sensor 13 as acceleration request detecting means. The depression amount θa is converted into an electric signal as driver's acceleration request information and input to the DBWECU 3.

The intake gas flows into the intake manifold 15 from the throttle body 8 via the surge tank 14, and becomes an air-fuel mixture by the fuel injected from the injector 1 according to a command from the DBWECU 3. The air-fuel mixture becomes exhaust gas after the explosion / expansion process of the engine 60 ends, flows into the exhaust manifold 16, and after harmful components are removed through an exhaust gas purification device (not shown), the mixture is introduced into the atmosphere from a muffler (not shown). Has been released. Reference numeral 24 denotes an engine rotation sensor that outputs engine rotation information,
Reference numeral 39 indicates a water temperature sensor. This engine 60
(See FIG. 10)
Is provided with a steering wheel, and a steering angle sensor 61 for outputting information on the steering wheel angle θh is attached thereto. In addition, the hydraulic booster mechanism of the steering device has a hydraulic pressure (here, a power steering base pressure) acting in the mechanism. A power steering pressure sensor 62 that outputs information on the power steering pressure Pst is attached to the power steering pressure sensor 62, and the detection information is output to the CVT ECU 21.

The continuously variable transmission 20 shown in FIG. 4 is connected to the crankshaft of the engine 60 via a fluid coupling 41 and a planetary gear type forward / reverse switching device 42. here,
The continuously variable transmission 20 includes a primary pulley 26 having a primary shaft 22 integrally connected to an output shaft of a forward / reverse switching device 42 and a secondary pulley 28 having a secondary shaft 29 for outputting a rotational force to the speed reducer 30. Primary pulley 26 and secondary pulley 28
The steel belt 27 is stretched. The secondary shaft 29 is configured to transmit torque to the drive wheels 32 of the drive shaft 31 via a speed reducer 30 and a differential (not shown). Both pulleys 26 and 28 are configured in two parts, and the movable-side pulley members 261 and 281 are externally fitted to the fixed-side pulley members 262 and 282 so as to be relatively non-rotatable and capable of coming and going at a relative distance. A primary cylinder 33 and a secondary cylinder 34 are mounted on the movable pulley members 261 and 281 as hydraulic actuators for operating to move relative to and away from the fixed pulley members.

A pair of rotation sensors s1 and s2 for detecting the rotational speeds Wp and Ws of the primary pulley 26 and the secondary pulley 28 are mounted as means for detecting the actual speed ratio in (= Wp / Ws). In this case, the movable pulley 261 is brought closer to the fixed pulley 262 of the primary pulley 26 to increase the winding diameter of the primary pulley, and the movable pulley 281 is separated from the fixed pulley 282 of the secondary pulley 28 and the winding diameter is increased. To reduce the actual transmission ratio in (primary rotational speed Wp
/ Secondary rotation speed Ws), that is, a low gear ratio (high gear position), and conversely, a high gear ratio (low gear position) is operated.
Is achieved. The hydraulic circuit of the continuously variable transmission 20 will be described with reference to FIG. This hydraulic circuit includes an oil pump 37, and discharge oil thereof is supplied to a fluid coupling 41.
Is supplied to the forward clutch 43 and the reverse clutch 44 of the forward / reverse switching unit 42 and the primary cylinder 33 and the secondary cylinder 34 of the continuously variable transmission 20.

Here, the oil pump 37 is driven according to the rotation of the engine to change the oil pressure thereof. For this reason CVTE
The maximum allowable pressure of the discharge pressure of the duty valve CU21 is regulated by the line pressure regulator valve 47,
In addition, the solenoid valve 40 and the regulator valve 48 operate to regulate the pressure so as to maintain the set line pressure.
A part of the line pressure line 49 is connected to a clutch pressure control valve 50, and the pressure oil adjusted to a set value by the valve is passed through a clutch oil line 51 to the manual valve 5.
2 is supplied. The manual valve 52 is interlocked with a manual shift lever for shifting gears, so that the forward side D,
2 and L, a reverse R range, and a neutral N and parking P range.

The manual valve 52 engages the forward clutch 43 when the range is forward D, 2 or L. At this time, the engine rotation is transmitted to the continuously variable transmission 20 as it is, while the engine rotation is transmitted when the reverse R range is set. It is reversed and transmitted to the continuously variable transmission 20. A part of the line pressure path 49 branches and is adjusted to a set value by the pressure control valve 53, and the oil pressure is supplied to the electromagnetic control valve 23, and is adjusted to the shift speed control pressure Pc according to the shift speed Vi by the valve. Pressed. The electromagnetic control valve 54 is connected to the CVT ECU 21
And outputs a shift speed control pressure Pc corresponding to the shift speed signal to a gear ratio control valve 54 described later.

The primary cylinder 45 of the continuously variable transmission 20
And the secondary cylinder 46 are respectively connected to a main port 541 and a sub port 542 of the speed ratio control valve 54,
In particular, the secondary cylinder 34 is directly connected to the line pressure path 49. Here, the gear ratio control valve 54 is
41, 542, a pilot port 543 for receiving the shift speed control pressure Pc of the electromagnetic control valve 23, and a pressure regulating port 5 for receiving the adjustment pressure from the pressure control valve 53.
44, a drain port X communicating with an oil tank 55 is provided, and switching control of an oil path is performed by a spool 56. Here, the spool 56 is connected to the pilot port 5
The portion opposing 43 receives the shift speed control pressure Pc to the left, and the other end receives the adjustment pressure and spring force in the opposite direction, and switches to the balance position. In this case, the spool 56
The drain port X is closed in response to the rightward movement (the shift speed control pressure Pc decreases), and is completely closed after a constant movement.
Further, after a certain movement, the main port 541 and the sub port 542 are moved.
, The primary pulley control oil pressure Pp of the primary cylinder 33 is increased (the secondary pulley control pressure is always the line pressure), and the actual speed ratio in is reduced to a low speed ratio (high gear). Conversely, the control oil pressure Pp can be decreased and the actual gear ratio in can be increased to achieve a high gear ratio (low gear stage).

The main parts of the DBWECU 3 and the CVT ECU 21 are both constituted by a microcomputer.
In the built-in storage circuit, the required power calculation map of FIG.
The reference torque calculation map of FIG. 6, the intake air amount calculation map of FIG. 7, the throttle opening calculation map of FIG. 8, the Kμ calculation map of FIG. 9, the engine output control processing routine of FIG. The control programs of the CVT control processing routine of FIG. 14, the ECU main routine of the DBWECU 3 of FIG. 15, and the μ calculation processing routine of the CVT ECU 21 of FIG. 16 are stored and processed. Where DB
The WECU 3 calculates the required power Po of the driver from the accelerator opening θa, temporarily sets the target torque T according to this value and the engine speed Ne, and applies the torque correction amount ΔTe (water temperature etc.) to the temporarily set target torque T. The target engine torque T1 is calculated by calculating the target engine torque T1, the throttle opening θs at which the target engine torque T1 and the engine speed Ne are obtained, and the valve 9 is controlled to the throttle opening θs. Provide functions.

On the other hand, the CVT ECU 21 uses the throttle opening θa and the vehicle speed V as primary pulley rotation speed calculating means.
The target primary pulley rotation speed Wpo is calculated, the friction coefficient μ of the traveling road surface is calculated as friction coefficient calculation means, and a lower value is set as the allowable maximum speed ratio IL as the friction coefficient μ is lower as the allowable maximum speed ratio setting means. calculates a target speed ratio I _SPR by the target primary pulley speed Wpo and the actual secondary pulley speed Ws as target gear ratio calculating means, corrected target speed ratio target gear ratio allows the I _SPR maximum speed ratio as a calculation means I _L To calculate the corrected target gear ratio I1, calculate the deviation gear ratio E1 between the corrected target gear ratio I1 and the actual gear ratio In as the deviation gear ratio calculating means, and calculate the deviation gear ratio E1 as the gear speed calculating means based on the deviation gear ratio E1. It has a function of calculating the shift speed Vi, calculating a shift speed signal Du corresponding to the shift speed Vi as the shift driving means, and driving the electromagnetic control valve 23 with the signal.

Here, an example of a method in which the CVT ECU 21 calculates the friction coefficient μ of the traveling road surface as friction coefficient calculation means is disclosed in the specification and drawings of Japanese Patent Application No. 2-179238 filed by the present applicant. The outline of the main part will be described below. In FIG. 10, when the right front wheel WFR is steered to the right by the steering angle δf, the sideslip angle βf of the right front wheel WFR, the cornering force CF, and the road surface friction coefficient μ maintain the relationship of CF∝βf · μ. Where the sideslip angle βf
On the other hand, the cornering force CF greatly changes depending on the road surface μ as shown in FIG.

By the way, the cornering force CF and the power steering pressure ΔP are in a relationship of ΔP = C1 · βf · μ (1) where C1 is a constant, and the side slip angle βf is the vehicle speed. V, the relation between the steering wheel angle [theta] h and the road surface mu is a constant C2, C3, βf = C3 · V 2 · θh / (μ + C2 · V 2) is in the relationship ........ (2). From these equations (1) and (2), ΔP / θa = μ · C1 / C3 · V ² / (μ + C2 · V ² ) (3) is obtained. μ = {1 + C2 · V ² / (C1 · C3 · V ² )} · ΔP / θa (4) μ = Kμ · ΔP / θa (5) Therefore, the road surface μ can be calculated from the power steering pressure ΔP, the steering wheel angle θh, and the vehicle speed V.

Hereinafter, a shift control device for a continuously variable transmission according to the present embodiment will be described with reference to control programs shown in FIGS. 12 to 16 and a block diagram shown in FIG. In this embodiment,
By operating an ignition key (not shown), the engine body 60 is started, and the DBWE shown in FIGS.
The control in the CU 3 and the CVT ECU 21 is also started.
When the control is started, the DBWECU 3 executes the main routine of FIG. Here, the initial setting and the detection data of each sensor are read and taken into a predetermined area.

In step c2, it is determined whether or not the fuel is in the fuel cut zone based on the engine speed Ne based on the output of the engine rotation sensor 24 and the engine load information (here, the intake air amount A / N) based on the output of the air flow sensor 6. Proceeding to step c3, the air-fuel ratio feedback flag
FBF is cleared, the fuel cut flag FCF is set to 1, and the routine returns. When it is determined that the fuel is not cut and the process reaches step c5, the fuel cut flag FCF is cleared and it is determined whether or not a known air-fuel ratio feedback condition is satisfied. At a time point when the condition is not satisfied, for example, in a transient operation range such as a power operation range, in step c12, an air-fuel ratio correction coefficient KMAP corresponding to the current operation information (A / N, N) is calculated,
This value is input to the address KAF, and the process proceeds to Step c9.

When it is determined that the air-fuel ratio feedback condition is satisfied and the process reaches step c7, the load information A
/ N and a target air-fuel ratio (target A / F) corresponding to the engine speed Ne, an actual air-fuel ratio (A / F) n is obtained based on the output of the air-fuel ratio sensor 2, and the target air-fuel ratio (A / F) Goal A
/ F) and the actual air-fuel ratio (A / F) n, the deviation ε is obtained, the deviation air-fuel ratio ε is subjected to a well-known PID process, and the normal feedback coefficient KFB is set. Then, this value is stored in the address KA
Then, the process proceeds to step c9.

In step c9, the other fuel injection pulse width correction coefficient KDT and the correction value TD of the dead time of the fuel injection valve are set in accordance with the operation state, and the process proceeds to step c10. In step c10, the ignition timing θadv is set based on a predetermined map (not shown) so as to increase according to the engine speed Ne. Thereafter, the process proceeds to an engine output control process described later in step c11, and thereafter returns to step c1. A fuel supply control routine (not shown) for controlling the injector 1 based on the air-fuel ratio feedback correction value KFB calculated in the main routine is executed based on a known control process.
An ignition drive routine (not shown) for outputting a control signal to the ignition circuit 17 to drive the ignition plug 2 to adv is executed based on a known control process.

In the engine output control process shown in FIG. 10, first, detection data of each sensor, for example, information such as the throttle opening θa and the engine speed Ne is taken into a predetermined area. In step a2, the required power Po is calculated from the throttle opening θa based on the required power Po calculation map shown in FIG.
The reference torque To is set using the torque calculation map (see FIG. 6) based on the engine speed Ne and the engine speed Ne. Step a3
In a4, the water temperature information WT is taken in, the friction loss torque T _WT of the sliding portion is calculated from a predetermined map (see FIG. 2), and the friction loss torque T _WT is added to the required torque To to determine the target torque T1, Proceed to step a5. Here, the intake air amount A according to the target torque T1 and the engine speed Ne.
/ N is obtained from the intake air amount calculation map of FIG. 7, and the throttle opening θs is calculated based on the intake air amount A / N and the engine speed Ne.
Is calculated based on the throttle opening θa calculation map of FIG. In step a6, the throttle opening θa and the actual opening θ
The difference Dun is calculated by calculating the difference of n, the output Dun which can eliminate the difference Δθ is calculated, and the output Dun is output to the pulse motor 11 to drive the throttle valve 9 to generate the target torque T1 in the engine. .

On the other hand, the CVT ECU 21 corresponds to FIG.
4, the CVT control is started, initialization is performed, and the rotation speeds Wp and Ws of the primary pulley 26 and the secondary pulley 28, the throttle opening degree θa from the DBWECU 3 and the engine rotation speed Ne, which are the detection data of the sensors. , The steering wheel angle θh, the power steering pressure Pst (power steering source pressure) and the like are taken in and stored in a predetermined area. In step b3, the vehicle speed V is calculated by multiplying the primary pulley rotation speed Wp by the reduction ratio α, and the process proceeds to step b4.

In step b4, a process for calculating the road surface μ is started. In the road surface μ calculating process shown in FIG. 16, first, at step d1, the steering wheel angle θst, the vehicle speed V, and the power steering pressure Ps
and t. Subsequently, the absolute value of the steering wheel angle θst becomes a predetermined value θ1 (for example, the dead zone is set to about 10 °).
If this is the case, the routine returns unless the device is mounted on step 3.

In steps d3, d4 and d5, the vehicle speed V and ΔP / θa corresponding to the road surface μ are calculated from the above equation (3).
Kμ = 1 + C2 · V ^{2, which is} obtained by equations (4) and (5)
^{/ (C1 · C3 · V 2} ) to by substituting vehicle speed V seek Kmyu, thereon, obtains the road surface μ a (= ΔP / θa · Kμ) . Thereafter, in step d6, it is determined whether or not the change rate of the road surface μ, that is, the differential value is within a predetermined value Δμ (for example, 0.2 μ / sec). If the determination is negative, the sudden change value of the road surface μ is eliminated as a disturbance value, and the process returns.
7, a filter process is performed to stabilize the road surface value, the road surface μ is output, and the process returns.

Returning to step b5 of the CVT control process,
Here, it is calculated from the maximum allowable speed ratio I _L map in FIG. 2 the permissible maximum speed ratio I _L in accordance with the road surface mu. The allowable maximum speed ratio _IL map is configured such that the lower the friction coefficient μ, the smaller the allowable maximum speed ratio _IL is set, and the occurrence of tire slip due to an increase in torque due to a large speed ratio is suppressed. In steps 6 and 7, the vehicle speed V and the throttle opening θa
Set more predetermined unillustrated maps than the target primary pulley speed WPO, and the target primary pulley speed WPO divided by the actual primary pulley rotation speed Ws, obtaining the target speed ratio I _SPR. Thereafter, step b8
In comparison with the target speed ratio I _SPR maximum allowable speed ratio I _L, the maximum allowable speed ratio I _L ≧ target speed ratio I _SPR, sets the target speed ratio I _SPR directly into the corrected target speed ratio I1, the maximum allowed In the case of the gear ratio I _L <the target gear ratio I _SPR , the target gear ratio I
_SPR is to be restricted to the allowable maximum speed ratio I _L from too big, a permissible maximum speed ratio I _L to the corrected target speed ratio I1.

In step b9, a deviation E1 between the corrected target transmission ratio I1 and the actual transmission ratio In is obtained.
α is set to be large, and the shift correction gain Kα is set to the deviation E
The reference shift speed Vi1 is calculated by multiplying by 1. Further, in steps b12 to b14, the unit average value ΔVi1 of the reference shift speed Vi1 input every unit time is integrated to calculate an integral term ΣΔVi1, and the integral term ΣΔVi1 is set to a predetermined change width (30% to 70%). Clipping is performed, and the value is multiplied by the integral correction coefficient to calculate the integral corrected shift speed ViI.

In steps b15 to b17, the shift speed Vi is determined by adding the reference shift speed Vi1 and the integral corrected shift speed ViI, and the pair of cylinders 33, 34 is set so that the shift speed Vi can be achieved by the two pulleys 26, 28. Of each pulley control oil pressure Pp, Ps, and further, a shift speed control pressure Pc capable of adjusting each pulley control oil pressure Pp, Ps,
A shift speed control pressure signal Du corresponding to the shift speed control pressure Pc is calculated, the electromagnetic control valve 23 is driven by the signal Du, and the continuously variable transmission 20 can approach the target speed ratio io at the shift speed Vi.

[0032]

As described above, the transmission control apparatus for a continuously variable transmission according to the present invention sets a lower value as the road surface friction coefficient is lower as the allowable maximum speed ratio, and sets the target speed ratio as the allowable maximum speed ratio. Calculates the corrected target gear ratio and regulates the shift speed based on the deviation gear ratio between the corrected target gear ratio and the actual gear ratio, and the electromagnetic control valve driven according to the gear speed controls the pulley control oil pressure of the hydraulic actuator. Adjust the pressure to switch both pulleys at the target speed . For this reason, the target gear ratio changes
If the speed ratio is exceeded, for example, when starting or throttle opening
Only when it is large, the corrected target gear ratio is calculated according to the road surface μ , that is, the driving force becomes excessive with respect to the road surface μ.
The correction is applied only at
Without slipping, it is possible to suppress a slip on a low μ road and improve driving feeling.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a shift control device for a continuously variable transmission as one embodiment of the present invention.

FIG. 2 is a functional block diagram of an electronic control unit in the apparatus of FIG.

FIG. 3 is a hydraulic circuit diagram of a continuously variable transmission used by the device of FIG.

FIG. 4 is a sectional view of a main part of a continuously variable transmission used by the apparatus of FIG. 1;

FIG. 5 is a characteristic diagram of a required power calculation map adopted by an electronic control unit in the apparatus of FIG. 1;

FIG. 6 is a characteristic diagram of a reference torque calculation map adopted by an electronic control device in the device of FIG. 1;

FIG. 7 is a characteristic diagram of an intake air amount calculation map adopted by an electronic control unit in the apparatus of FIG. 1;

FIG. 8 is a characteristic diagram of a throttle opening calculation map adopted by an electronic control unit in the apparatus of FIG. 1;

9 is a characteristic diagram of a Kμ calculation map adopted by an electronic control device in the device of FIG. 1.

10 is a diagram showing a relationship between a side slip angle of a front right wheel and a cornering force of a steering device of a vehicle including the continuously variable transmission shown in FIG.

11 is a characteristic diagram showing a relationship between a side slip angle and a cornering force applied to a vehicle provided with the continuously variable transmission of FIG.

FIG. 12 is a flowchart of an engine output control processing routine adopted by the electronic control unit in the apparatus of FIG. 1;

FIG. 13 shows a CV adopted by the electronic control unit in the apparatus shown in FIG.
It is a flowchart of the front part of a T control processing routine.

FIG. 14 shows a CV adopted by the electronic control unit in the apparatus of FIG.
It is a flowchart after a T control processing routine.

FIG. 15 shows an EC used by the electronic control unit in the apparatus shown in FIG.
It is a flowchart of a U main routine.

FIG. 16 is a flowchart of a μ calculation processing routine adopted by the electronic control unit in the apparatus of FIG. 1;

FIG. 17 is a functional block diagram of an electronic control device in a conventional device.

[Explanation of symbols]

Reference Signs List 3 DBWECU 12 Throttle opening sensor 20 Continuously variable transmission 21 CVT ECU 23 Electromagnetic control valve 26 Primary pulley 27 Drive belt 28 Secondary pulley 33 Primary cylinder 34 Secondary cylinder 61 Steering angle sensor 62 Power steering pressure sensor s1 Rotation sensor s2 Rotation sensor μ Road surface Friction coefficient I _L Maximum allowable speed ratio θst Handle angle I _SPR target speed ratio V Vehicle speed

──────────────────────────────────────────────────続 き Continued on 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 (1)

(57) [Claims] A pair of pulleys are mounted on a primary pulley and a secondary pulley on which a drive belt is wound, and the gap between the pulleys is increased or decreased so that a winding diameter ratio of the two pulleys has a value corresponding to a predetermined speed ratio. A hydraulic actuator, a friction coefficient calculating means for calculating a friction coefficient of a traveling road surface, an allowable maximum speed ratio setting means for setting a lower value as the friction coefficient is lower as an allowable maximum speed ratio, and a designated target primary pulley rotation. Target speed ratio calculating means for calculating a target speed ratio based on the number and the actual primary pulley rotation speed; and a corrected target speed ratio calculating means for calculating the corrected target speed ratio by regulating the target speed ratio to the maximum target speed ratio. A shift speed ratio calculating means for calculating a shift speed ratio between the corrected target speed ratio and the actual speed ratio, and a shift speed calculation for calculating a shift speed based on the shift speed ratio. And a shift drive unit that calculates a shift speed signal corresponding to the shift speed and drives an electromagnetic control valve. The pair of hydraulic actuators are driven by the electromagnetic control valve being driven according to the shift speed signal. A shift control device for a continuously variable transmission, wherein the pulley control hydraulic pressure is adjusted to switch between the two pulleys at a target shift speed.