JP2825815B2 - Control device for automatic continuously variable transmission for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial application field The present invention relates to a continuously variable transmission, and more particularly to an automatic transmission for a vehicle suitable for use in a continuously variable transmission having a belt-type continuously variable transmission (CVT). The present invention relates to a control device for a step transmission, and more particularly, to a control device for traveling on a low friction (μ) road such as a snowy or frozen road surface.

(B) Conventional technology Recently, due to demands for improving the fuel consumption rate and driving performance, an automatic continuously variable transmission incorporating a belt-type continuously variable transmission has been receiving attention as a vehicle transmission.

As this kind of automatic continuously variable transmission for vehicles, Japanese Unexamined Patent Publication No.
As shown in Japanese Patent Publication No. 2155, a device provided with a slip prevention device has been proposed. The slip prevention device includes: a slip detection unit configured to detect a slip of a drive wheel; and a stepless transmission configured to reduce a rotational force of the drive wheel while the slip detection unit detects a slip of the drive wheel. Gear ratio changing means for changing the gear ratio, particularly when the road surface is in a snow-covered state or a frozen state and slips, so that the rotational force of the drive wheels is reduced until the slip disappears. The ratio is changed to escape from the slip state when the vehicle starts or while the vehicle is running.

(C) Problems to be Solved by the Invention However, when a slip is detected, the above-described slip prevention device travels by reducing the driving torque of the drive wheels in order to prevent the slip from being detected. Get
When the slip is eliminated, the control returns to the normal control, so that the slip easily occurs again. For example, when a vehicle starts on a snow-covered road or the like, even if the vehicle is started after the occurrence of slip is prevented by the above-described slip prevention device, when returning to normal control thereafter, hunting such as occurrence of a slip again and a change in gear ratio is performed. In particular, in the case where a part of the road has a very low μ such that the road is frozen, if the vehicle enters the low μ part in the normal control state, the above-described slip control is newly set. There is a possibility that it may not be in time.

Therefore, according to the present invention, once the slip control is set, the target torque ratio is corrected so as to correspond to the slip condition, and control is performed based on the corrected target torque ratio during a series of traveling. It is an object of the present invention to provide a control device for an automatic continuously variable transmission for a vehicle, which solves the above-mentioned problems.

(D) Means for Solving the Problems The present invention has been made in view of the above-described circumstances, and, when shown with reference to FIG. 1, a continuously variable transmission that continuously changes the rotation of an input member ( 30) and speed change operation means (100)
A target torque ratio setting means (121) for setting a target torque ratio determined in a running situation; and controlling the rotation of an engine (E). Torque ratio changing means (122) for changing the target torque ratio to be small when the drive wheels (W) transmitted via the step transmission (1) cause slipping; A correction amount corresponding to the changed torque ratio is set based on the signal of the means (122);
Correction amount setting means (123) for correcting the target torque ratio with the correction amount; and release means (145) for releasing the setting by the correction amount setting means based on a reset switch or a vehicle stop signal. The shift operation means (100) is controlled based on the target torque ratio corrected by the correction amount setting means until the setting by the correction amount setting means (123) is released by the cancellation means. And

As an example, a slip detecting means (141) for detecting a slip of the driving wheel (W) is provided, and the torque ratio changing means (122) is configured to detect a slip of the driving wheel (W) based on a signal of the slip detecting means (141). Is detected, the torque ratio is changed to a state where the slip disappears.

Note that the automatic continuously variable transmission (1) includes a fluid coupling (1) in addition to a continuously variable transmission (for example, a belt-type continuously variable transmission 30).
1) and an input device (10) comprising a lock-up clutch (12), and a low-high speed mode switching device (20) capable of switching between a low speed mode (L) and a high speed mode (H). Thus, the low-speed mode switching device (20)
A first element (for example, a ring gear 21R) connected to an output portion (30a) of the continuously variable transmission (30) and a second element (for example, a carrier) connected to an output member (70) of the continuously variable transmission. 21C) and a planetary gear device (21) having a third element (for example, a sun gear 21S) connected to the input member (60) of the continuously variable transmission (1), and a locking means (F or B).
1) connecting to the third element (21S),
By interposing a clutch (C2) between the element and the input member (60), the operation of the locking means (F or B1) causes the planetary gear device (21) to function as a speed reduction mechanism, and It is preferable that the planetary gear device (21) functions as a split drive mechanism to be in the high-speed mode by setting the mode to the non-operating mode and connecting the clutch (C2).

The torque ratio changing means (122) is provided with a torque ratio change limit setting means (142) for regulating the change of the torque ratio so as not to be less than a minimum predetermined torque ratio determined by a running condition, and an extremely low friction coefficient is provided. It is better if it is configured so as to prevent the traveling performance from being excessively shifted in the direction (O / D direction) in which the torque ratio becomes high (O / D direction) on the road consisting of, thereby impairing the starting performance.

As another example, a manual setting means for manually setting the driving wheel (W) in response to the slip of the driving wheel (W) is provided, and the torque ratio changing means (122) is provided with a driving wheel (W) set by the manual setting means. ) Is changed to the torque ratio in a state where the slip is eliminated. That is, the slip detecting means (14
In addition to or instead of 1), there is provided a manual setting means (143) for predicting the slip of the drive wheel (W) in advance and setting by the driver, and the manual setting means (143) provides the correction amount setting means (123). ) May be set for, for example, a jersey road or a snowy road, and control may be performed with a target torque ratio based on the set value.

Further, in the state where the target torque ratio is corrected by the correction amount setting means (123) based on the signal of the torque ratio changing means (122), the continuously variable transmission operating means (30) for operating the continuously variable transmission (30) A shift operation speed setting means (125) for setting the operation speed of 101) to be slow may be provided.

Similarly, when the target torque ratio is corrected by the correction amount setting means (123) based on the signal of the torque ratio changing means (122), the operation of the lock-up clutch (12) is released. Control release means (126) may be provided.

The release of the correction amount setting means (123) is performed by a release means (14) comprising a reset switch or a vehicle stop signal.
Performed by 5).

(E) Operation Based on the above configuration, the rotation of the engine (E) is continuously variable by the automatic continuously variable transmission (1), and the changed rotation is transmitted to the drive wheels (W) to start the vehicle. To run. At this time, the target torque ratio is set by target torque ratio setting means (121) of the control unit (120) so as to meet a predetermined specification such as a maximum power characteristic or a best fuel consumption characteristic. The shift operation means (100) is controlled so as to reach the target torque ratio. When the vehicle starts or runs on a low μ road and slips on the driving wheel (W), for example, the slip is detected by the slip detecting means (141), and a signal from the detecting means is output. Based on this, the torque ratio changing means (122) changes the torque ratio so as to be lower, and the torque ratio is changed until the driving wheel (W) no longer slips. Further, the torque ratio in a state where the slip detecting means (141) detects that the slip has disappeared is sent to the correction amount setting means (123), and the setting means determines a predetermined relationship corresponding to the torque ratio, for example, The correction amount is set based on a predetermined ratio, a predetermined difference, or a corresponding predetermined characteristic. Then, the target torque ratio is corrected on the basis of the correction amount, and the continuously variable transmission (1) shifts in accordance with the corrected target torque ratio during a series of traveling until a reset signal or a release signal such as stop is input. Controlled.

In addition, the signal from the torque ratio change limit setting means (142) restricts the torque ratio change means (122) from falling below the minimum predetermined torque ratio determined by the running conditions, and is used on extremely low μ roads such as frozen roads. Even so, the torque ratio is prevented from being reduced as much as possible, and the starting performance is compensated.

When the target torque ratio is changed by the torque ratio changing means, the speed change operation speed setting means (125) sets the operation speed of the continuously variable speed change operation means (101) to be low, and the lock-up control release means (126) regulates the operation of the lock-up clutch (12), and operates the vehicle smoothly to eliminate the cause of the slip.

(F) Examples Hereinafter, examples that embody the present invention will be described.

First, an automatic continuously variable transmission according to the present invention (for details, see
No. 61-205614, Japanese Patent Application No. 62-214378 or Japanese Patent Application No. 62-3304
2 will be described with reference to the schematic diagram shown in FIG. 2. The continuously variable transmission 1 includes an input device 10 including a fluid coupling 11 and a lock-up clutch 12, an auxiliary transmission 40, and a belt-type continuously variable transmission. The device 30 includes an output member 70 including a reduction gear device 71 and a differential gear device 72. The auxiliary transmission device 40 includes a transfer device 80, a low-high speed mode switching device 20 including a single planetary device 21 and a mode switching engagement device 22,
And a forward / reverse switching device 90 including a dual planetary device 91, a reverse brake B2, and a forward clutch C1. And the single planetary gear device 21
First element 21R coupled to output 30a of continuously variable transmission 20
(Or 21S), a second element 21C connected to the output member 70 of the continuously variable transmission 1, and a third element 21S (or 2S) connected to the input shaft 60 from the input device 10 via the transfer device 80.
1R). The mode switching engagement device 22 for switching the planetary gear device 21 between the high-speed mode H and the low-speed mode L includes a locking means including a low one-way clutch F and a low coast and reverse brake B1, and a high clutch C2. Third element serving as a reaction force support member when means F and B1 are used as a speed reduction mechanism in low speed mode L
21S (or 21R) through a transfer device 80, and the high clutch C2 is connected to the input shaft 60 and the third element 21.
Interposed between S. Specifically, the ring gear 21R of the planetary gear device 21 is linked to the output portion 30a of the continuously variable transmission 30, the carrier 21S is linked to the output member 70, and the sun gear 21S is connected to the low one-way clutch F via the transfer device 80. It is linked to the low coast & reverse brake B1 and to the high clutch C2.

In the dual planetary gear device 91, the sun gear 91S is connected to the input shaft 60, and the carrier 91C is connected to the input portion 30b of the continuously variable transmission 30, and is connected to the input shaft 60 via the forward clutch C1, and The ring gear 91R is connected to the reverse brake B2.

Based on the above configuration, each clutch, brake and one-way clutch in the automatic continuously variable transmission 1 operate at each position as shown in FIG. Note that * indicates that the lock-up clutch 12 can be operated appropriately,
S1, S2, and S3 indicate the operation of a solenoid valve described later.

More specifically, in the low speed mode L in the D range, the low one-way clutch F operates in addition to the connection of the forward clutch C1. In this state, the rotation of the engine crankshaft is transmitted to the input shaft 60 via the lock-up clutch 12 or the fluid coupling 11, further transmitted directly to the sun gear 91S of the dual planetary gear device 91, and transmitted to the carrier via the forward clutch C1. It is transmitted to 91C. Accordingly, the dual planetary gear device 91 rotates integrally with the input shaft 60, and rotates in the forward direction with the belt-type continuously variable transmission 30.
And the rotation appropriately shifted by the continuously variable transmission 30 is transmitted from the output unit 30a to the ring gear 21R of the single planetary gear device 21. On the other hand, in this state, the sun gear 21S,
Is stopped by the low one-way clutch F via the transfer device 80, so that the rotation of the ring gear 21R is taken out of the carrier 21C as a deceleration rotation, and further the axle shaft 73 is transmitted through the reduction gear device 71 and the differential gear device 72. Is transmitted to

In the high speed mode H in the D range, the high clutch C2 is connected in addition to the forward clutch C1.
In this state, similarly to the above, the forward rotation appropriately shifted by the continuously variable transmission 30 is extracted from the output unit 30a and input to the ring gear 21R of the single planetary gear unit 21. Meanwhile, at the same time, the rotation of the input shaft 60 is controlled by the single planetary gear device via the high clutch C2 and the transfer device 80.
The torque of the ring gear 21R and the torque of the sun gear 21S are combined by the planetary gear device 21 and output from the carrier 21C. At this time, since rotation against the reaction force is transmitted to the sun gear 21S via the transfer device 80, a predetermined plus torque is applied to the transfer device 80 without generating a torque environment.
Is transmitted via Then, the synthesized carrier 21
The torque from C is transmitted to the axle shaft 73 via the reduction gear device 71 and the differential gear device 72.

In the low-speed mode operation in the D range, when the reverse torque is actuated (during engine braking) based on the one-way clutch F, it is free in the SH and SL ranges.
The reverse brake B1 operates to transmit power even when the reverse torque is applied.

In the R range, the reverse brake B2 operates together with the low coast & reverse brake B1. In this state, the rotation of the input shaft 60 is input to the belt-type continuously variable transmission 30 as reverse rotation from the carrier 91C based on the fact that the ring gear 91R is fixed by the dual planetary gear device 91. On the other hand, based on the operation of the low coast and reverse brake B1, the sun gear of the single planetary gear unit 21
21S is fixed, and therefore reverse rotation from the continuously variable transmission 30 is reduced by the planetary gear unit 21 and the output member 70
Is taken out.

Next, a control device of the automatic continuously variable transmission will be described with reference to FIG.

The present control device (system) U includes an electronic control device 120 including a microcomputer, a hydraulic control device 150, an external signal device including various sensors, operation means, a display device, and various actuators. Electronic control unit
Reference numeral 120 stores a predetermined pattern such as a best fuel consumption characteristic, a maximum power characteristic, an engine brake control, an L-H switching control, a slip control, etc., performs a predetermined calculation, and displays a display device 173, a driver 177, and each hydraulic pressure described later. It outputs to each control part 153,103,102 of the control device 150. Also, the hydraulic control device 150
As will be described in detail later along FIG. 5, a hydraulic pressure generation (pump) unit 151, a line pressure control unit 152, a shift pressure control unit 153,
The vehicle includes a start (input) control unit 103, an LH switching control unit 102, a speed selection unit 157, and the like. The external signal device is provided with a throttle opening sensor 16 provided in the engine E portion.
1, a primary pulley rotation speed sensor 165, a secondary pulley rotation speed sensor 166, a vehicle speed sensor 167, and a motor rotation signal sensor 169 provided in the automatic continuously variable transmission 1.
And a foot brake signal sensor provided in the driver's seat
170, a shift position sensor 171, which detects a selected position of a shift lever, a pattern sensor 172, which allows a driver to select and operate various patterns such as economy and power, various display devices 173, and a friction coefficient (μ) of a gravel road, a snow-covered road surface, etc. Switches 143a and 143 for the driver to select different low μ roads
Low μ consisting of b and slip control reset switch 145
It has a road control switch unit 175 and the like. Further, the actuator is a fluid coupling disposed on the input device 10.
11, a lock-up clutch 12, a low coast and reverse brake B1, a high clutch C2, a forward clutch C1, and a reverse brake provided in the auxiliary transmission device 40.
B2, and belt-type continuously variable transmission 3 via driver 177
It has a shift electric motor 101 for shifting control of 0 and a brake 180 for holding the motor in a shift position.

Further, the hydraulic control device 150 will be described with reference to FIG.

The hydraulic control device 150 includes a hydraulic pressure generation unit 151 such as a pump, a line pressure control unit 152, a shift pressure control unit 153, a start control unit 103, L
-H switching control section 102 and speed selection section 157. Further, the hydraulic pressure generating section 151 has an oil pump 181 and a pressure relief valve 182, and sucks oil in a tank via a strainer 183 to generate a predetermined hydraulic pressure. Further, the line pressure control section 152 consists of the regulator valve 185, supplies a hydraulic pressure generated by the pump 181 with pressure regulated to a predetermined line pressure P _L, the surplus flow oil passage b, a secondary pressure to c. Note that a check valve 186 is interposed in the oil passage c to prevent reverse flow of oil from the fluid coupling 11. The shift pressure control unit 153 includes a shift pressure control valve 187 that is duty-controlled by the first solenoid valve S1, regulates the line pressure of the line pressure oil passage a to a predetermined shift pressure, and supplies the line pressure to the oil passage d. . The L-H switching control unit 102 includes an L-H shift control valve 189 that is duty-controlled (or on-off controlled) by a second solenoid valve S2, and is supplied via an oil passage l and a throttle check valve 192. port m ₁ of the hydraulic and the oil passage j, and the throttle check hydraulic port n ₁ supplied via the valve 193 by regulating the predetermined fluid pressure that each port m ₂ and the oil passage h, port n ₂ and the oil passage j To the high clutch C2 and the low coast & reverse brake B1 to switch the mode (L → H). The start (input) control unit 103 includes a third solenoid valve S
A lock-up control valve 190, which is duty-controlled (or on-off controlled) at 3, changes the flow direction of oil in a lock-up off oil passage e and a lock-up on oil passage f, as well as the port q ₂ and oil passage The lock-up off pressure supplied via e is adjusted to a predetermined oil pressure. The speed selector 157 is composed of a manual valve 191 operated by a driver using a shift lever, and communicates the port line pressure or the port shift control pressure with each port indicated by a circle at each position as shown in the table. I do.

Since the hydraulic control device 150 has the above configuration, the hydraulic pressure from the pump 181 is adjusted to the line pressure by the regulator valve 185, and the line pressure is supplied to the port of the manual valve 191 via the oil passage a. The excess flow of the regulator valve 185 is used as the secondary pressure as oil passage b
Supply to each lubrication point and check valve 18
The fluid is supplied to the fluid coupling 11 through the fluid passage 6 and the oil passage c. On the other hand, the line pressure in the oil passage a is communicated with port k ₁ of the shift pressure control valve 187, pressure is regulated appropriately shift pressure by duty control of the solenoid valves S1, the shift pressure port k ₂
Is supplied to the port of the manual valve 191 via the oil passage d.

Now, when the manual valve 191 is in the N range or the P range, the port and the port are shut off. In this state, the first and second solenoid bubbles S
Although 1 and S2 do not affect the hydraulic servos C1, C2, B1 and B2 at all, it is desirable that both are turned on in preparation for the next control. In this state, all hydraulic servos C1, C2,
No hydraulic pressure is supplied to B1 and B2. Therefore, as shown in FIG. 3, the forward clutch C1, the high clutch C2, the low coast and reverse brake B1, and the reverse brake B2
Is inactive.

When the manual valve 191 is operated from the N range to the D range, the port remains in the closed state, but the port communicates with the port. And the solenoid valve S1
Is supplied to the oil passage 1 via the oil passage d and the port, and further supplied to the forward clutch hydraulic servo C1 through the oil passage g. Incidentally, the shift pressure is supplied to port m ₁ shift valve 189 via the oil path l and the aperture check valve 192, the second solenoid valve S2 is kept on, the shift valve is the right half position port m ₂ is in the drain port x and the communication state with the port m ₁ is closed in the. Accordingly, only the forward clutch C1 is connected to enter the low speed mode L state. The forward clutch based on the shift pressure by the duty control of the first solenoid valve S1
When the smooth shifting of the C1 completed, the first solenoid valve S1 is turned off, the shift pressure control valve 187 becomes the left half position, and the port k ₁ and k ₂ are communicated. In this state, the line pressure acts directly on the ports of the manual valve 191 via the ports k ₁ and k ₂ and the oil passage d, so that the line pressure is supplied to the oil passage l and the forward clutch hydraulic servo C1. Then, the forward clutch C1 is securely engaged.

Then, the electronic control device 120, when switching to H mode is determined, the second solenoid valve S2 is duty controlled, it is supplied to the port m ₁ via the oil path l and the aperture check valve 192 lines pressure pressure adjusted to a predetermined pressure,該調pressurized hydraulic is supplied to the high clutch hydraulic servo C2 through port m ₂ and the oil passage h, high clutch C2 is smoothly connected. The second solenoid valve S2 after the shift completion is turned off, switched shift valve 189 is in the left half position, the port m ₁ and m ₂ are communicated, the line pressure port of the oil passage l m _1, m ₂ and an oil It is supplied to the high clutch hydraulic servo C2 via the path h. As a result, the high clutch C2 is connected together with the connection of the forward clutch C1, and the high-speed mode H state is set.

Further, when the manual valve 191 is operated in the SH or SL range, the communication state with the port is maintained and the port communicates with the port. In this state, the predetermined shift pressure of the port (the line pressure after the shift is completed) is supplied to the forward clutch hydraulic servo C1 and the line pressure of the oil passage a is changed to the oil passage i, and further supplied to the port n ₁ of the shift valve 189 via the throttle check valve 193. When the electronic control unit 120 determines that the mode is the L mode (switching from the D range L and H mode to the S range L mode), the port is controlled by the duty control of the second solenoid valve S2.
the line pressure to be supplied to the n ₁ is pressurized predetermined tone, is supplied to the low coast and reverse brake hydraulic servo B1 through the ports n ₂ and the oil passage j. Thereby, B1 connects smoothly. After the shift is completed, the second solenoid valve S2 is turned on by a signal from the electronic control unit 120, the LH shift control valve 189 is set to the right half position, and the port n
₁ and n ₂ are in communication, and the line pressure at port n ₁ is
It is supplied to the low coast & reverse brake hydraulic servo B1 via ₂ and the oil passage j. Therefore, the low coast & reverse brake B1 operates together with the forward clutch C1 to enter the S range low speed mode L state. The same applies when switching from the S range H mode to the L mode.

When the electronic control unit 120 determines that the mode is switched from the S range L mode to the H mode, the duty of the second solenoid valve S2 is controlled and the high clutch C2 Connect smoothly.

In S range L mode, low coast &
The line pressure is supplied to the reverse brake hydraulic servo B1, but when the mode is switched from the L mode to the H mode,
Port m ₁ and m ₂ and communicates the hydraulic high clutch servo C2
Before hydraulic pressure starts to be supplied to ports, ports n ₁ and n ₂ are shut off and port n ₂ communicates with drain port x, and hydraulic servo B1 for low coast & reverse brake is drained, and low coast & reverse brake B1 is released. When the connection of the high clutch C2 is completed, the second
Is turned off, the line pressure is supplied to the high clutch hydraulic servo C2, and the high-speed mode H state is set.

On the other hand, when the manual valve 191 is operated to the R range, the port and the port communicate with each other. Further, the second solenoid valve S2 is in the ON state by a signal from the electronic control unit 120. In this state, the shift pressure from the port is supplied to the reverse brake B2 via the port and the oil passage o, and the line pressure of the port is supplied to the port of the shift valve 189 via the oil passage i and the throttle check valve 189. is supplied to n _1, it is supplied to the low coast and reverse brake B1 via the further port n ₂ and the oil passage j of the valve 193 to the right half position. On this occasion,
The hydraulic pressure from the oil passage o acts on the feedback port p of the regulator valve 185 to set the line pressure to a higher value. Similarly, shift pressure control is performed by the first solenoid valve S1, and smooth shift operation and reliable engagement are guaranteed.

When the electronic control unit 120 determines that the lock-up is OFF → ON in the D range and the S range, the third control is performed.
The solenoid valve S3 is duty controlled and port q ₁
Is adjusted to a predetermined oil pressure, and acts on the right side of the lock-up clutch 12 via the port q ₂ and the oil passage e (lock-up off pressure). At this time, the port s ₁ and the port s ₂ are in communication with each other, and the oil pressure in the oil passage r is introduced into the fluid coupling 11 through the ports s ₁ and s ₂ and the oil passage f, and acts on the left side of the lock-up clutch 12. (Lock-up on pressure). The lock-up clutch 12
Are connected smoothly. 3rd solenoid valve S3 is OF
In the state of F (lock-up OFF), the lock-up control valve 190 is at the left half position, and the secondary pressure from the oil passage c is applied to the fluid coupling via the ports q ₁ and q ₂ and the oil passage e.
11 and is discharged through the oil passage f, so that the lock-up clutch 12 is in the disconnected state, but in the right half position when the third solenoid valve S3 is ON (lock-up ON), S ₁ and S ₂ communicate and port q ₂
Communicates with the drain X, hydraulic pressure from the port is introduced into the fluid coupling 11 through the oil passage r, the ports s ₁ and s ₂ and the oil passage f, and acts on the lock-up clutch 12, so that the lock-up clutch 12 Is connected. Note that, even when the lock-up is on, it is also possible to perform the duty control and perform the slipping control of the lock-up clutch without turning on the third solenoid valve S3.

Next, the operation of the electronic control unit 120 according to the present embodiment will be described with reference to FIG.

Belt-type continuously variable transmission 3 based on a rotation signal from motor rotation signal sensor 169 and an alarm signal from driver 177.
An operation limit (stroke end) of 0 is detected, and the rate of change is detected from the throttle sensor 161 in consideration of the throttle opening and the soft timer. Also, the primary pulley rotation speed (N
p), the number of rotations of the secondary pulley (N _s ) is detected, and the rate of change is detected in consideration of the vehicle speed and the soft timer based on the signal from the vehicle speed sensor 167. In addition, a pattern such as economy mode and power mode is detected by a signal from the pattern switch 172, and a shift position sensor is further detected.
The signals from 171 detect the respective ranges of P, R, N, D, SH, and SL, and detect a change in the shift position. The signal from the foot brake sensor 170 detects the brake operation state.

Then, the acceleration request determination unit 200 makes a predetermined determination based on the detected values of the throttle opening degree and its change rate, the vehicle speed and the change rate, and the current belt ratio calculation unit 201 based on the primary pulley rotation number and the secondary pulley rotation number. A torque ratio (hereinafter simply referred to as a belt ratio) Tp of the current belt-type continuously variable transmission 30 is calculated. Further, based on the belt ratio from the calculating unit 201 and the current low-speed or high-speed mode signal from the HL selection determining unit 203 described later, the current system ratio calculating unit 202 Calculate the torque ratio (hereinafter referred to as the system ratio) a _p . On the other hand, based on signals from the acceleration request determination unit, the pattern detection value, and the shift position detection value, the maximum power / best fuel consumption determination unit 205 determines whether to perform control based on the best fuel consumption characteristics or the maximum power characteristics. The target system ratio upper / lower limit calculation unit 206 calculates the target torque ratio (system ratio) of the entire transmission based on the signal from the determination unit 205, the throttle opening, the vehicle speed, and the brake detection signal. Calculate the lower limit values a ^* _max and a ^* _min . Further, based on the calculation unit 206, the target belt ratio calculation unit 207 calculates a target torque ratio (belt ratio) T ^* _L in the low speed mode and a target torque ratio T ^* _H in the high speed mode of the belt-type continuously variable transmission.

Then, the acceleration request determination unit 200, the throttle opening detection value, the current belt ratio calculation unit 201, the current system ratio calculation unit 20
2, based on signals from the primary pulley rotation number detection value, the secondary pulley rotation number detection value, the best fuel efficiency, the maximum power determination unit 205, the target system ratio upper / lower limit calculation unit 206, and the target belt ratio calculation unit 207, It is better for the L selection determining unit 203 to achieve the target system ratio a ^* only by shifting the belt-type continuously variable transmission 30 in the current mode, or by switching the mode (L → H, H → L) Determine if it is better to achieve the ratio a ^* . Then, in addition to the high-speed mode H or low-speed mode L signal from the determination unit 203, the stroke end detection value, the acceleration request determination unit 200, the current belt ratio calculation unit 2
01, throttle opening detection value, target belt ratio calculation unit 207,
Based on the signal from the target system ratio upper / lower limit calculation unit 206, the CVT shift control signal generation unit 210
A predetermined rotation signal is issued to the driver 177 so as to enter the upper / lower limit values a ^* _max and a ^* _min of the target system ratio in the predetermined mode determined in the above, and the motor 101 is rotated so that the belt-type continuously variable transmission 30 Is controlled to a predetermined value. Further, based on the throttle opening detection value, the P, N, D, SH, SL detection value, and the shift position change detection value, the shift pressure control signal generation unit 211 controls the manual valve N → D, N → R, D → R , R → D, a duty signal is issued to control the first solenoid valve S1. Further, when the HL switch control signal generator 212 determines to switch to the low speed or high speed mode based on the HL selection determination unit 203 and the signal of the throttle opening detection value, a switch signal is issued and the second signal is output. The switching of the solenoid valve S2 is terminated by the duty. Further, the lock-up control signal generator 213 turns on / off or duty-controls the third solenoid valve S3 based on the signals of the HL selection determining unit 203, the detected values of the throttle opening and the primary pulley rotation speed.

In the present embodiment, a slip detection processing unit 215 is installed in the electronic control unit 120 in addition to the above-described control. The processing unit 215
The manual setting signals μ1 (143a) and μ2 (143b) from the low μ road control switch unit 175 and the reset signal (14
5) is input, and the vehicle speed detection value, the change rate detection value thereof, and the throttle opening detection value are input.
Slip of the drive wheel and vehicle stop are detected. In addition,
As shown by a chain line in FIG. 4, the slip detection processing unit 215 includes a drive wheel rotation sensor 141a and a driven wheel rotation sensor
The slip from the drive wheel may be directly detected by inputting the signal from 1b and comparing the rotation speeds from both sensors. And
The signal from the slip detection processing unit 215 is input to the target system ratio upper / lower limit calculation unit 206, and the target system ratio a ^* is reduced until no slip is detected, and the system ratio is stored. Further, by comparing the reduced system ratio with the original system ratio, an appropriate correction value to be described later is changed, and the target system ratio upper / lower limit based on the target system ratio corrected by the correction value. Is calculated.

Further, based on the signal from the determination unit 215, the control is performed such that the CVT shift speed control signal generation unit shifts later than usual.

Then, the slip detection signal from the slip detection processing unit 215 is released by a reset signal (145) or a stop of the vehicle running.

Next, the operation of the control device to which the slip control according to the present embodiment is added will be described with reference to FIGS. 7 to 13.

First, the main flow will be described with reference to FIG. 7. A process F1 for reading an input signal from a sensor, a process F2 for detecting a slip described later, and a process F3 for calculating an actual belt torque ratio of the belt-type continuously variable transmission. , A process F4 for calculating the actual system ratio from the current mode (H mode or L mode), a process F5 for calculating the target system ratio upper / lower limit from the throttle opening, the vehicle speed, the driving mode, and the auxiliary transmission device. A process F6 for determining whether to set the low-speed mode or the high-speed mode, based on the above determination and the calculated value, the continuously variable transmission unit so that the current system ratio falls within the upper and lower limits of the target system ratio. A process F7 for controlling the shift direction and the speed of the gearshift, and a process F8 for controlling the solenoid valves S1, S2, and S3 are sequentially performed.

Next, will be described more in detail slip detection processing F2, as shown in Figure 8, compared with the previous vehicle speed V _B of the current repeated at the vehicle speed V _P Start → return (V _P -V _B → ΔV)
(F10), the difference ΔV is compared with a preset slip determination set value α (F11), and if the vehicle speed change ΔV is larger than the set value α (ΔV> α), the drive wheel is in a slip state. And sets the slipping flag A and the slip control flag B (A = 1, B = 1) (F1
2). Then, in step F13, the target primary pulley rotation speed N ^* (substantially the same as the engine output rotation speed) and the slip are set based on the current travel control mode (the maximum power characteristic P or the best fuel efficiency characteristic E) and the throttle opening θ. Based on the actual primary pulley rotational speed N _P that is up-shifted based on this, the (N _P / N ^* ) reduction rate δ is calculated. On the other hand, if the vehicle speed variation ΔV is smaller than the slip determination set value α in step F11, the slipping flag A is reset (A = 0).
(F14) Further, in step F15, it is determined whether the vehicle is currently stopped, and in step F16, it is determined whether the reset switch 145 is on. If both are NO, the flow merges with the flow from the previous step F13. In step F17, the current vehicle speed is stored (V _P → V _B ) to prepare for the next slip determination, and
If YES, the slip control flag B is reset (B = 0) (F18). FIG. 9 shows the throttle opening θ.
And the relationship between the vehicle speed V and the vehicle speed variation ΔV. In step F11, if the actual vehicle speed variation is larger by a predetermined amount than ΔV in the graph, it is determined that the vehicle is slipping.

Next, the target system ratio upper / lower limit calculation F5 based on the slip detection processing will be described in detail. As shown in FIG. 10, a manual control switch 143 is determined on or off at step F20, whether the selected further If on, at step F21 mu ₁ or mu ₂ Kano either state to decide.
When μ ₁ is selected, the target primary pulley rotation speed (substantially the same as the engine output rotation speed) N ^* is set along the curve indicated by Nμ ₁ shown in FIG. 11 (F22), and μ _{When 2} is selected, the target primary pulley rotation speed N ^* is set along the Nμ ₂ curve. On the other hand, when the manual control switch 143 is off, the target primary pulley rotation speed N ^* corresponding to the travel control mode currently set in step F24, for example, the maximum power curve P or the best fuel consumption curve E ^*.
Set. Then, in step F25, it is determined whether or not the vehicle is currently slipping. If the vehicle is not slipping, it is further determined in step F26 whether or not the vehicle is under slip control. The correction mode curve _NN is newly set by multiplying N ^* by the decrease rate δ, and the target rotation speed N ^* is set along the curve. When the vehicle is slipping, a preset curve for a low μ road is set in advance.
A target rotation speed N ^* is set along N _CAL (F28). Then, the upper and lower limits of the target rotation speed are set from the target rotation speed N ^* set in steps F22, F23, F27 or F28 (N ^* + N _U =
N ^* _U , N ^* + _NL = N ^* _L ), current vehicle speed _VP and coefficient C,
In step F29, target system ratio upper / lower limit values a ^* _max , a ^*
_min is set ((N ^* _U / _VP ) × C = a ^* _max , (N ^* _L /
V _P ) × C = a ^* _min ).

The correction mode curve N _N for slip control, as shown in Figure 12 (a), a predetermined ratio based on the reduction rate ^{_{N P / N * = δ (}} a: b), i.e., predetermined travel control mode curve E Alternatively, the value is not limited to the value obtained by multiplying P by the decrease rate δ, and may be set by another method. For example, as shown in FIG. 12 (b), the difference between the actual rotation speed at the end of the slip and the target rotation speed (N _P −N ^* → ΔN) is stored, and the difference ΔN is stored in the predetermined traveling control mode curve E. or it may set the correction mode curve N _N subtracted from P. Further, as shown in FIG. 12 (c), a number of correction mode curves _NN are set in advance corresponding to the reduction rate δ, and based on the reduction rate δ calculated in step F13 from among these modes. You may make it select.

FIG. 13 shows a control flow of the continuously variable transmission shifting actuator.

In F41, the actual system ratio and target torque ratio
The lower limit value is compared, and if it is within the upper / lower limit range, a stop signal is output to the speed change actuator (F48). a ^* _min <a _P <a ^*
If not _max , the target torque ratio is calculated from each mode and the target system ratio. In case of L mode as shown in Fig. 14
In the T ^* _L and H modes, T ^* _H is set as the target belt torque ratio (F42, F43, F44). If T ^*> T _P by comparing the actual belt torque ratio T _P and the target belt torque ratio T ^* at F45, downshift signal (F 46), if T ^* ≦ T _P, upshift signal (F
47) is output. Further, the shift speed of the system ratio is set based on the difference (deviation amount) between the actual engine speed and the target engine speed (see FIG. 15). In S49, if the slip control flag B = 1, the shift speed is set to be slow (F50, e = g (x)), and the slip control flag B is set.
= 0, the normal shift speed is set (F51, e = f
(X)). Further, the sheave movement speed is controlled so that the shift speed of the system ratio becomes e (F52) (see FIG. 16). As an example, the upshift in the high-speed mode will be described. The current system ratio is taken (point P), and F50,
The shift speed determined in 51 is taken parallel to the horizontal axis (l ₁ ), and a line segment is drawn from that point parallel to the vertical axis (l ₂ ). In proportion to the magnitude of the l _2, we make decisions to control the belt unit shift speed. In other cases, such as at the time of the L mode and at the time of downshift, the same operation is performed.

FIG. 17 is a flowchart showing the control of the solenoid valves S1, S2, S3. In step F53, duty control of the first solenoid valve S1 is performed at the time of shift positions N → D and N → R, and in step F54, switching is performed from L → H or H → L by the second solenoid valve S2. Control is performed. Then, it is determined in step F55 whether or not the slip control is being performed.
The lock-up clutch control by the solenoid valve S3 is performed (F56), and during the slip control, the lock-up clutch control is maintained in the off state (F57).

(G) Effects of the Invention As described above, when the drive wheels slip, the target torque ratio is changed so as not to be small, and a correction amount corresponding to the changed torque ratio is set. Since the shift operation means (100) is controlled at the target torque ratio corrected by the amount setting means (123), once slippage occurs, the vehicle travels with the corrected low driving force during a series of travels, and again Slip can be prevented from occurring, and stable running can be maintained.

In addition, a slip detecting means (141) for detecting slip of the drive wheel is provided, and the torque ratio is changed so that the detected slip is eliminated, and when a correction amount corresponding to the torque ratio is set, it is possible to cope with the slip of the drive wheel. It is possible to prevent the occurrence of slip and maintain stable running even on a partially low-μ road where some roads are frozen by automatically setting an accurate correction amount to be performed. .

Further, a manual changing means (143) for predicting the slip of the driving wheel in advance and setting by the driver is provided, and when the correction amount of the correction amount setting means (123) is set by the manual changing means, the snowy road, the dirt road, Alternatively, it can be set in advance so as not to cause a slip according to a gravel road or the like, and it becomes possible to easily perform advanced driving techniques.

Furthermore, if the operation speed of the continuously variable transmission operation means (101) is made slower during the slip control, the acceleration and deceleration operations are made slower, and the occurrence of slip can be prevented more reliably.

Further, when the lock-up clutch control is turned off during the slip control, the control is performed smoothly via the fluid coupling (11), and the occurrence of slip can be more reliably prevented.

Further, when the torque change limit setting means (142) is provided, even on a road surface where slippage is extremely likely to occur, it is possible to prevent infinitely upshifting and insufficient driving force, thereby impairing startability.

[Brief description of the drawings]

FIG. 1 is a functional block diagram according to the present invention. FIG. 2 is a schematic diagram showing an automatic continuously variable transmission to which the present invention can be applied, and FIG. 3 is a diagram showing the operation of each element in each position. 4 is a block diagram showing a control device according to the embodiment of the present invention, FIG. 5 is a diagram showing a hydraulic control circuit thereof, and FIG. 6 is a block diagram showing an electronic control device of the present embodiment. FIG. 7 is a main flow showing the operation of the present embodiment, and FIG. 8 is a flow showing the slip detection processing. FIG. 9 is a diagram showing a change in vehicle speed depending on the vehicle speed and the throttle opening. FIG. 10 is a flowchart showing the calculation of the target torque ratio (system ratio) of the continuously variable transmission during the slip control, and FIG. 11 is a diagram showing each correction mode curve.
FIGS. 12 (a), (b), and (c) are diagrams showing a method of calculating different correction mode curves. FIG. 13 is a float showing the control of the continuously variable transmission shifting actuator, and FIG. 14 is a diagram showing the relationship between the belt torque ratio and the system torque ratio. FIG. 15 is a diagram showing a relationship between a shift speed and a deviation amount. FIG. 16 is a view showing the relationship between the sheave position of the continuously variable transmission section and the system ratio. FIG. 17 is a flowchart showing control of each solenoid valve. DESCRIPTION OF SYMBOLS 1 ... Automatic continuously variable transmission, 10 ... Input device, 11 ... Fluid coupling, 12
... lock-up clutch, 20 ... low-speed mode switching device, 30 ... (belt type) continuously variable transmission device, 100 ... transmission operation means, 101 ... continuously variable transmission operation means (motor), 103 ... lock-up control means, 110 ... Shift state detection means, 120 ... (electronic)
Control unit, 121: target torque ratio setting unit, 122: torque ratio changing unit, 123: correction amount setting unit, 125: shift operation speed setting unit, 126: lock-up control release unit, 141: slip detection unit, 142: torque Ratio change limit setting means, 143: manual setting means, 145: release means.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Norio Imai 10 Takane, Fujii-machi, Anjo, Aichi Prefecture Inside Aisin AW Co., Ltd. (72) Yukihiro Nagata 10 Takane, Fujii-cho, Anjo, Aichi Prefecture Aisin・ In AW Co., Ltd. (56) References JP-A-60-192155 (JP, A) JP-A-62-292535 (JP, A) JP-A-62-292536 (JP, A) JP-A 64-64 79466 (JP, A) Japanese Utility Model Showa 61-114146 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) F16H 61/10

Claims (1)

(57) [Claims] 1. A continuously variable transmission for continuously changing the rotation of an input member, and a control device for an automatic continuously variable transmission for a vehicle comprising a shift operation means, wherein a target torque ratio determined in a running condition is determined. Target torque ratio setting means for setting, and torque ratio changing means for changing the target torque ratio to be small in a case where a drive wheel transmitted through the continuously variable transmission causes the rotation of the engine to slip. A correction amount setting unit that sets a correction amount corresponding to the changed torque ratio based on a signal of the torque ratio changing unit, and corrects the target torque ratio with the correction amount; and a reset switch or a stop of the vehicle. Release means for releasing the setting by the correction amount setting means on the basis of the signal, and the correction amount setting means until the setting by the correction amount setting means is released by the release means. Based on the target torque ratio which is corrected Te, formed by controlling the shift operation means, the control device in the vehicular automatic continuously variable transmission, characterized in that.