JPH0774671B2 - Control device for automatic transmission for vehicle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automatic transmission for a vehicle capable of achieving a plurality of shift speeds, and a shift that occurs when shifting from one shift speed to another shift speed. The present invention relates to a control device for a vehicle automatic transmission that can reduce shock.

[Prior Art] In a conventional automatic transmission for a vehicle, for example, the one disclosed in Japanese Patent Publication No. 56-47427, the rotational acceleration of a rotation input member of the transmission during shifting converges to a preset target rotational acceleration. As described above, feedback control is performed on the hydraulic pressure supplied to the friction engagement device involved in gear shifting according to a function of the difference between the rotational acceleration and the target rotational acceleration, and the engagement force of the engagement device is corrected to reduce gear shift shock. Was configured as. Here, general feedback control will be briefly described.

The feedback control is a control (P control) in which a proportional value of a difference between a target value and an actual value is used as a correction amount in the next control cycle, and an integral value and / or a differential value of the difference are added to the proportional control. There is control (PID control) as a correction amount, and the correction gain for obtaining the correction amount in these controls is set according to the proportional value, integral value, and derivative value of the difference.

By the way, in the technique of controlling so that the actual value of the input shaft rotational acceleration coincides with the target input shaft rotational acceleration during gear shifting of the automatic transmission, when feedback control based on the above general idea is used, a certain gear shift ( For example, if the difference between the target value and the actual value in the 4-3 downshift) and the difference between the target value and the actual value in the other shift (for example, 3-2 downshift) are the same, The correction amount is substantially the same regardless of the magnitude of the transmission torque. (It slightly changes when the differential value and the integrated value are taken into consideration.) [Problems to be solved by the invention] However, the friction engagement device is configured so that the rotational acceleration of the rotational input member does not deviate from the target rotational acceleration. Even if the hydraulic pressure supplied to the motor is electrically controlled, it is stable due to the response delay of the hydraulic pressure and the delay for the calculation time of the correction amount of the engaging force according to the difference between the target acceleration and the actual rotational acceleration. Feedback control cannot be achieved, and the rotational acceleration does not converge to the target rotational acceleration and vibrates around the target rotational acceleration (Fig. 5 (a)), and in particular, the viscosity of oil is high and a response delay occurs. The hydraulic pressure control supplied to the friction engagement device becomes unstable at a low temperature when it is easy to cool, or at a high temperature when oil leakage from the rotary seal increases (Fig. 5 (b)), the shift shock becomes large, and Phil Ring had problem of significant loss (FIG. 5 (c)). Conversely, if the gain of the oil pressure correction amount is set to a relatively small value in order to prevent the above-mentioned vibration, the feedback control will be delayed, and the shift will be completed without the convergence of the rotational acceleration to the target rotational acceleration during the shift period. There was a problem that did.

Furthermore, since the input shaft rotation acceleration changes greatly according to the transmission torque at that time (the larger the transmission torque, the larger the acceleration), so this change in acceleration can be reflected in the correction amount by the differential control, but the automatic shift If the actual value is converged to the target value within an extremely short period of time, such as when shifting the machine, the control tends to be delayed, and it is difficult to achieve the intended purpose.

[Structure of the Invention] The present invention has been devised in view of the above, and provides a plurality of gear stages by engaging or releasing a plurality of friction engagement devices interposed between an input shaft, an output shaft, and the same input / output shaft. Of the gear engagement mechanism, an engagement force adjusting device that adjusts the engagement force of the friction engagement device, an electronic control device that controls the adjusting device, and a rotation speed of the input shaft that is detected and responds to the rotation speed. And a rotation speed sensor for inputting a rotation speed signal corresponding to the rotation speed signal to the electronic control device, wherein the electronic control device is configured to detect the rotation speed signal from the rotation speed signal. A calculating means for calculating the rotational acceleration of the input shaft and a change rate of the same acceleration, a target setting means for setting a target rotational acceleration of the input shaft according to an engine load, and the rotational acceleration and the target rotational acceleration during shifting. Difference and rotation A correction unit that corrects the engagement force of the frictional engagement device so that the rotational acceleration matches the target rotational acceleration in accordance with the rate of change in speed, and a correction gain of the correction amount by the correction unit that is the engine load or the A control device for an automatic transmission for a vehicle, comprising: a correction gain setting means that is set according to a target rotation speed;

[Operation] According to the present invention, the engaging force of the frictional engagement device is adjusted so that the rotational acceleration of the input shaft during gear shifting converges to the preset target rotational acceleration and the rotational acceleration of the input shaft. The feedback control is performed so that the rate of change of R is always 0 based on the correction gains a and b, and the correction gain itself is set according to the engine load or the target rotational acceleration, so that the engine load is large. Sometimes the target rotational acceleration also becomes large, so by detecting the engine load or target rotational acceleration, when the value is large, it is determined that the transmission torque is also large, and the correction gain is set to a large value. Conversely, when the engine load is small, Since the target rotational acceleration is also small, if the value is small by detecting the engine load or the target rotational acceleration, Determines that the transmission torque is also small, and the correction gain is set to a small value.

Embodiments Embodiments of the present invention will be described in detail with reference to the drawings.

In FIG. 1, a crankshaft 12 of an engine 11 which is a power source of a vehicle is integrally connected to a pump 14 of a torque converter 13. The torque converter 13 is the pump
14 Turbine 15 and one-way clutch 17 through case
The stator 16 is connected to 18, and the stator 16 rotates in the same direction as the crankshaft 12 by the action of the one-way clutch 17, but is not allowed to rotate in the opposite direction. . The torque transmitted to the turbine 15 is transmitted by the input shaft 19 to the gear shift mechanism that is arranged at the rear of the turbine 15 and that achieves four forward gears and one reverse gear.

The gear shifting mechanism is composed of three sets of clutches 20, 21, 22 and two sets of brakes 23, 24, one set of one-way clutch 25 and one set of Ravigneaux type planetary gear set 26. The planetary gear mechanism 26 includes a ring gear 27, a long pinion gear 28,
A short pinion gear 29, a front sun gear 30, a rear sun gear 31, both pinion gears 28, 29 are rotatably supported and are also constituted by a carrier 32 which is also rotatable, and a ring gear 27 is connected to an output shaft 33 and a front sun gear 30.
Is connected to the input shaft 19 via the kickdown drum 34 and the front clutch 20, and the rear sun gear 31 is a rear clutch.
21 is connected to the input shaft 19, and the carrier 32 is connected to the case 18 via a low reverse brake 24 and a one-way clutch 25 which are arranged in parallel with each other, and is arranged at the rear end of the gear transmission mechanism. It is connected to the input shaft 19 via a four-speed clutch 22 provided. Kick down drum
The kick down brake 23 can be integrally connected to the case 18, and the torque passing through the planetary gear mechanism 26 is transmitted from the output gear 35 fixed to the output shaft 33 to the drive wheels through a drive shaft (not shown). Transmitted.

Each of the clutches 20 to 22 and the brake 23, which are friction elements,
Each of the torque converters 24 is composed of a hydraulic device including an engaging piston device or a servo device.
It is selectively operated via a hydraulic control device by pressure oil generated by an oil pump (not shown) connected to a pump 14 of 13.

The first speed stage of the gear shift mechanism having the above configuration releases the front clutch 20, the fourth speed clutch 22 and the low reverse brake 24 (however, when the select lever is set to the first speed fixed range, the low reverse brake is used). 24 is engaged), the rear clutch 21 is engaged, and the one-way clutch 21
This is achieved by fixing the carrier 32 by the lock mechanism of.

The second speed gear stage is achieved by engagement of the rear clutch 21 and the kick down brake 23. Therefore, the gear shift from the first speed fixed range to the range in which another forward speed can be achieved without the operation of the celt lever from the first speed to the second speed is performed only by engaging the kick down brake 23. In this case, when the rotation speed of the kick-down drum 34 starts to decrease due to the engagement of the kick-down brake 23, the carrier 32 starts to rotate in the direction allowed by the one-way clutch 25, and the kick-down drum 34 further moves. The second speed is achieved when the rotation speed decreases and finally stops.

FIG. 2 shows a part of the hydraulic control device that achieves the above-mentioned shift speed. A 1-2 shift valve 37 is connected to a kick down servo 36 for controlling the operation of the kick down brake 23 through an oil passage 38, and the 1-2 shift valve 37 has a hydraulic control valve 39 and a shift control valve 40. And are communicated with each other via oil passages 41 and 42, respectively. The hydraulic control valve 39 is connected to an oil passage from an unillustrated hydraulic source.
The pressure oil (line pressure) supplied to 50 is adjusted to a desired oil pressure value according to the control oil pressure in the oil passage 51 and is supplied to the oil passage 41. The control oil pressure in the oil passage 51 is The electromagnetic valve 55 is duty-controlled by the electronic control unit 54 so that the discharge is appropriately controlled and adjusted to a desired pressure. In the shift control valve 40, the central spool 47 is controlled by the pair of solenoid valves 43, 44 whose combination of the deenergized states is controlled by the electronic control unit 54 so as to shift gears from the first speed to the fourth speed. Is controlled to be switched to a position corresponding to.

In the state where the first speed gear stage is achieved in the hydraulic control device having the above-described configuration, the solenoid valve 43 is excited to discharge the hydraulic pressure in the oil passages 45 and 46, so that the spool 47 is located at the left end shown in FIG. The oil passage 42 communicates with the oil discharge port EX of the shift control valve 40. Therefore, the spool 49 of the 1-2 shift valve 37 is located at the left end portion shown in FIG. 2, the oil passage 38 is communicated with the oil discharge port EX of the 1-2 shift valve 37, and the kick down servo is performed.
Since the piston 53 of 36 is aligned to the right in FIG. 2 by the action of the compression coil spring 56, the kick down brake 23 is released from the kick down drum 34. When shifting from this state to the second speed, the rotation speed signal from the rotation speed sensor 60 that detects the rotation speed of the input shaft 19 connected to the electronic control unit 54 and the throttle valve opening from the throttle valve opening sensor 61 are opened. The electronic control unit 54 according to a predetermined operating state of the vehicle determined based on a vehicle speed signal from the vehicle speed detection device 62 that detects the vehicle traveling speed by detecting the rotation speed of the output shaft 33 and the rotation speed signal. Since a speed change signal to the second speed is generated to demagnetize the solenoid valve 43 to close the oil passage 45 and to excite the solenoid valve 44 to open the oil passage 46 to discharge the oil pressure in the oil passage 46. , The spool 47 is moved to a position where the oil passage 48 and the oil passage 42 communicate with each other, the line pressure from the oil passage 48 is supplied to the 1-2 shift valve 37, and the spool 49 of the 1-2 shift valve 37. 2 moves to the right end position in FIG. 2 to bring the oil passage 41 and the oil passage 38 into communication with each other. When the operation of the solenoid valve 55, which will be described later, is stopped, the control hydraulic pressure in the oil passage 51 reaches the maximum pressure and the line pressure from the oil passage 50 is supplied to the oil passage 41 without being reduced. The pressure tightens the kick down drum 34 to achieve the second speed.

Here, the control mode during the shift from the first speed to the second speed in the above mechanism will be described with reference to the flow chart shown in FIG. 3 and the characteristic curve shown in FIG.

While the vehicle in the state in which the conventionally known select lever is not moved to the first speed fixed position is traveling at the first speed gear, the operating state of the vehicle satisfies the predetermined upshift condition, and the electronic control unit 54 When this is judged and a shift command (step (1)) is generated, step (2) for starting the program in the control device 54 is executed.

Then, in step (3), the duty ratio of the solenoid valve 55 is commanded to the solenoid valve 55 as a relatively small value d0 (FIG. 4 (i)), and the control oil pressure in the oil passage 51 is not significantly reduced. As a result, a relatively high hydraulic pressure from the oil passage 50 is supplied to the kickdown servo 36 via the 1-2 shift valve 37 and the oil passage 38, and the kickdown brake 23 is initially engaged with the kickdown drum 34 in a short time. Combined state (kick down brake 23
For a certain period of time after the command for setting the duty ratio to a relatively small value d0 is issued in step (3) in step (4). Then, a determination process for determining whether or not the kick down brake 23 is in the initial engagement state is executed.

If the determination result in step (4) is NO, that is, if it is determined that the kick down brake 23 is not in the initial engagement state because the predetermined time has not yet elapsed, the process returns to step (3), and YES If it is determined that the duty ratio of the solenoid valve 55 is set to the duty ratio d1 corresponding to the predetermined initial engagement hydraulic pressure, the process of instructing is executed in step (5) (FIG. 4 (ii)).

Next, in step (6), the duty ratio d1 is decreased at a predetermined inclination angle α with respect to time, that is, at a predetermined change speed, and the control hydraulic pressure in the oil passage 51 is gradually increased at a predetermined speed, A process of increasing the hydraulic pressure supplied from the oil passage 41 to the kickdown servo 36 via the 1-2 shift valve 37 and the oil passage 38 at a predetermined changing speed is executed. Then, the hydraulic pressure gradually rises and the kick down brake is applied.
The engagement of 23 with the kickdown drum 34 gradually increases, and finally the rotation speed of the kickdown drum 34 starts to decrease (that is, the input shaft 19 also deviates from the rotation speed corresponding to the first speed), and effective gear shift starts. If the judgment result is NO, that is, if it is judged that the effective gear shifting has not started yet, the process returns to step (6) and YES, that is, the above-mentioned effective. If it is determined that the gear shift has started (FIG. 4 (iii)), the rotation speed V of the input shaft is detected based on the output signal from the rotation speed sensor 61 which detects the rotation speed of the input shaft in step (8). Then, in step (9), the throttle valve opening T is detected based on the output signal from the throttle valve opening sensor 60 which detects the throttle valve opening, and in step (10), the shift according to the throttle valve opening T is performed. Input shaft inside 19 Target rate of change of the rotational speed, i.e. the target rotation acceleration A (the throttle valve opening degree T
When A is small, A is set to a small value to alleviate the shift color, and when T is large, A is set to a large value to prevent wear of the friction engagement device. In step (11), a calculation for obtaining the actual rotational acceleration B of the input shaft 19 is executed based on the rotational speed V of the input shaft, and in step (12) the rotational acceleration B of the input shaft 19 is calculated.
The calculation for obtaining the change rate C of is performed.

Then, in step (13), the gain a of the duty ratio correction amount related to the correction amount of the rotational acceleration of the input shaft 19 is set, and in step (14), the gain b of the correction amount of the rotational acceleration change ratio of the input shaft 19 is set. . Here, the gains a and b change according to the throttle opening T indicating the engine load or the target rotational acceleration A. And step (15)
Is the difference AB between the target rotational acceleration A and the rotational acceleration B,
From the rate of change C of the rotational acceleration B and the gains a and b set in the step (13) and step (14), the duty ratio d1 is corrected so that the AB is 0 and the C is 0. The calculation for obtaining the corrected duty ratio Δd is performed, and in step (16), a new duty ratio Nd in which the corrected duty ratio Δd is added to the duty ratio currently commanded to the solenoid valve 55 is obtained. A process of commanding the duty ratio Nd to the solenoid valve 55 is executed (see FIG. 4 (i
v)).

Then, in step (17), a process of determining whether or not the rotation speed of the input shaft 19 becomes a value corresponding to the second speed and effective gear shifting is completed is executed, and if NO is determined, step (8)
The feedback control including step (16) is executed again, and the feedback control is repeatedly executed until the determination in step (17) becomes YES.

Then, the judgment in step (17) is YES (Fig. 4 (v)).
Then, the operation of the solenoid valve 55 is stopped, the line pressure is supplied to the kick down servo 36, and the step (18) of instructing to increase the engaging force of the kick down brake 23 is executed,
The next step (19) is executed and the program ends (Fig. 4 (vi)).

As described above, the target rotation speed A and the rotation acceleration B of the input shaft 19 which are determined according to the throttle valve opening T after the effective gear shift is started in shifting from the first gear to the second gear. Is controlled by feedback control of the duty ratio of the solenoid valve 55 so that the change rate C of the rotational acceleration B becomes 0, and the hydraulic pressure supplied to the kickdown servo 36 is feedback controlled. The acceleration B quickly converges to the target rotational acceleration A without vibrating around the target rotational acceleration A, stable feedback control is achieved, and moreover, there is much oil leakage from the seal at low temperatures where oil viscosity is high. Even when the temperature is high, it is possible to obtain a good shift feeling in which the fluctuation of the output shaft torque during the shift is small.

Further, since the correction gain itself is also configured to be set according to the engine load or the target rotation acceleration, for example, when the engine load is large, the target rotation acceleration also becomes large. Therefore, the correction gain is corrected according to the engine load or the target rotation acceleration. The effect of setting a large gain, shortening the convergence time to the target value, shortening the sliding time (shift time) of the friction engagement device, reducing heat generation of the engagement device, and suppressing secular change of the device Play.

On the contrary, when the engine load is small, the target rotational acceleration is also small. Therefore, the correction gain can be set small according to the engine load or the target rotational acceleration, and a large change in the engaging force is eliminated, so that smooth gear shifting can be obtained. .

It should be noted that in the present implementation, a relatively high hydraulic pressure is supplied to the kickdown servo 36 for a predetermined time so that the kickdown brake 23 is initially engaged with the kickdown drum 34 in a short time. However, a potentiometer that detects the piston position of the kick down servo 36 and outputs a position signal is provided, and the kick down servo 36 is relatively high until the piston moves and a predetermined position signal is output from the potentiometer. The hydraulic pressure may be supplied.

Further, in the present embodiment, the control during the shift from the first gear to the second gear has been described.
By performing the same control at the time of the 3, 3-4, 4-3, 3-2, 2-1 shift, a good shift feeling with a small output shaft torque fluctuation can be obtained in any shift. Is.

[Advantages of the Invention] According to the present invention, in an automatic transmission for a vehicle in which a plurality of gear stages are obtained by engaging or disengaging a plurality of friction engagement devices, the rotational acceleration of the input shaft during gear shifting is detected to detect the same acceleration. Is converged to the target rotational acceleration set according to the driving state of the vehicle, the difference between the two rotational accelerations and the rate of change in the rotational acceleration of the input shaft are set to always 0 based on the correction gains a and b. Since the hydraulic pressure supplied to the friction engagement device is controlled and the correction gain itself is set according to the engine load or the target rotational acceleration, for example, when the engine load is large, the target rotational acceleration is also large. Therefore, the correction gain can be set to a large value according to the engine load or the target rotational acceleration, and the convergence time to the target value can be shortened and the sliding time of the friction engagement device can be reduced. (Shift time) is shortened, heat generation of the engagement device is reduced, and secular change of the device can be suppressed.

On the contrary, when the engine load is small, the target rotational acceleration is also small. Therefore, the correction gain can be set small according to the engine load or the target rotational acceleration, and a large change in the engaging force is eliminated, so that smooth gear shifting can be obtained. .

Furthermore, the above-mentioned rotational acceleration converges to the target rotational acceleration, stable feedback control is achieved, and the output shaft torque of the output shaft torque is reduced even at low temperature when oil viscosity is high and response delay is likely to occur, or at high temperature when oil leakage from the rotary seal increases. It is possible to obtain an excellent shift feeling with little fluctuation.

[Brief description of drawings]

FIG. 1 is a schematic structural view showing a power train of an automatic transmission to which the present invention is applied, FIG. 2 is a hydraulic circuit diagram showing a main part of a hydraulic control device of the automatic transmission, and FIG. FIG. 4 is a flow chart showing a control state of the embodiment, and FIG. 4 is a graph showing respective changing characteristics of the rotation speed of the input shaft 19, the supply pressure to the kick down servo 36 and the output shaft torque with respect to time in the above embodiment. 11 …… Engine 12 …… Crankshaft 21 …… Rear clutch 23 …… Kickdown brake 25 …… One way clutch 26 …… Ravigneaux type planetary gear mechanism 32 …… Carrier 33 …… Output shaft 34 …… Kickdown drum 36… … Kickdown servo 37 …… 1-2 shift valve 39 …… hydraulic control valve 40 …… shift control valve 54 …… electronic control device 55 …… solenoid valve 60 …… rotation speed sensor 61 …… throttle valve opening sensor 62 ...... Vehicle speed detection device

Claims (1)

[Claims] 1. A gear speed change mechanism, which is provided between an input shaft, an output shaft, and the same input / output shaft to obtain a plurality of gear stages by engaging or releasing a plurality of friction engagement devices, and the friction engagement. An engaging force adjusting device that adjusts the engaging force of the device, an electronic control device that controls the adjusting device, a rotation speed signal of the input shaft that detects the rotation speed of the input shaft, and a rotation speed signal that corresponds to the rotation speed of the input shaft. In the vehicular automatic transmission including a rotation speed sensor for inputting the rotation speed signal to the electronic control device, the electronic control device calculates a rotation acceleration of the input shaft and a change rate of the same acceleration from the rotation speed signal. And a target setting means for setting a target rotational acceleration of the input shaft according to the engine load, a difference between the rotational acceleration and the target rotational acceleration during shifting, and a rate of change of the rotational acceleration. Above rotational acceleration Correction means for correcting the engagement force of the friction engagement device so as to match the target rotational acceleration, and correction gain setting means for setting the correction gain of the correction amount by the correction means according to the engine load or the target rotation speed. And a control device for an automatic transmission for a vehicle, comprising: