JPH06129528A - Speed change controller of automatic transmission - Google Patents

Abstract

PURPOSE:To prevent a feeling of retarded speed change when power is turned OFF after a power-on/down-shift is started. CONSTITUTION:A first friction engagement device 21 is released while a second friction engagement device 22 is engaged to carry out power-on/down-shifting, and the engagement oil pressure of the first friction engagement device 21 is directly adjusted by a pressure adjustment device 23 which is controlled electrically, by the speed change controller of an automatic transmission A. The speed change controller is provided with a speed change detection means 24 for detecting power-on/down-shifting, a rotation speed detection means 25 for detecting the rotation speed of a predetermined rotating member, the rotation speed of which is increased at the time of down-shifting, a release means 26 for controlling the pressure adjustment means 23 so that the first friction engagement device 21 is immediately released when the rotation acceleration of the rotating member becomes a negative level, after the down-shifting is started, and an engagement means 27 for engaging the second friction engagement device 22 at the same time as the release of the first friction engagement device 21 or after the release.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling a shift of an automatic transmission, and directly adjusts an engagement hydraulic pressure of a friction engagement device involved in the shift by an electrically controllable means such as a solenoid valve. The present invention relates to a shift control device for an automatic transmission that is configured to be pressed to control the speed of engagement or disengagement.

[0002]

2. Description of the Related Art As is well known, an automatic transmission for a vehicle is constructed so that a plurality of gears can be set by appropriately engaging or disengaging a friction engagement device such as a clutch or a brake. The engagement / disengagement control of the friction engagement device is performed by supplying / discharging hydraulic pressure based on the running state of the vehicle such as vehicle speed and throttle opening. During gear shifting, the rotation of the rotating members that make up the gear train of the automatic transmission fluctuates, so the engagement or disengagement of the frictional engagement device may be affected by the transient energy in order to absorb the inertial energy associated with the rotation fluctuation. Cause slippage. Further, when the plurality of friction engagement devices are switched to execute the gear shift, the engagement hydraulic pressure of the other friction engagement device is controlled in accordance with the engagement state of one friction engagement device. The timing of engagement and release is taken.

For example, in an automatic transmission A provided with a gear train shown in FIG. 6, it is possible to set five forward gears and one reverse gear, and among them, between the first speed and the second speed. It is necessary to switch the engaged / released states of at least two friction engagement devices at the time of shifting and shifting between the second speed and the third speed and shifting between the fourth speed and the fifth speed. is there.

First, the structure of the gear train will be described. In FIG. 6, an automatic transmission A has a torque converter 2 having a lockup clutch 1 as a speed change mechanism and a second speed change portion having a set of planetary gear mechanisms. 3 and a first transmission unit 4 that sets a plurality of forward gears and reverse gears by two sets of planetary gear mechanisms. Second transmission section 3
Is for performing high-low two-stage switching, the carrier 5 of the planetary gear mechanism is connected to the turbine runner 6 of the torque converter 2, and the carrier 5
Between the sun gear 7 and the sun gear 7, a clutch C0 and a one-way clutch Fo are provided in parallel with each other, and a brake B0 is provided between the sun gear 7 and the housing Hu.

The sun gears 8 and 9 in each planetary gear mechanism of the first transmission section 4 are provided on a common sun gear shaft 10, and the left side (front side) of the first transmission section 4 in the drawing.
Of the planetary gear mechanism and the second speed change portion 3
A first clutch C1 is provided between the sun gear shaft 10 and the ring gear 12 of the second speed change portion 3, and a second clutch C2 is provided between the sun gear shaft 10 and the ring gear 12 of the second transmission portion 3. The carrier 13 of the planetary gear mechanism on the left side of the drawing and the ring gear 14 of the planetary gear mechanism on the right side (rear side) in the first transmission unit 4 are integrally connected, and the carrier 13 and the ring gear 14 have an output shaft. 15 are connected.

A first brake B1 which is a band brake is provided to stop the rotation of the sun gear shaft 10,
More specifically, it is provided on the outer peripheral side of the clutch drum of the second clutch C2, and the first one-way clutch F1 and the second brake B2 are arranged in series between the sun gear shaft 10 and the housing Hu. Further, the second one-way clutch F2 and the third brake B3 are arranged in parallel between the carrier 16 and the housing Hu in the planetary gear mechanism on the rear side.

In this automatic transmission A, the gears of 5 forward gears and 1 reverse gear are set by engaging and releasing the friction engagement devices as shown in FIG. In FIG. 7, the mark ◯ indicates engagement, the mark ◎ indicates engagement during engine braking, and the blank indicates release.

As known from the operation table of FIG. 7, in the automatic transmission having the gear train shown in FIG.
Since the clutch C0 and the brake B0 are switched between the engaged and disengaged states during the upshift and the downshift,
A one-way clutch F0 is provided to achieve smooth switching, and in a hydraulic circuit (not shown), the oil passage is configured so that the hydraulic pressure is not simultaneously supplied to the clutch C0 and the brake B0, and both of them have a predetermined value or more. The pressure is regulated by an accumulator so that it does not have torque capacity.

By the way, when the hydraulic pressure to the friction engagement device is regulated by controlling the accumulator and its back pressure, the pressure regulation characteristic may be restricted by the capacity of the accumulator and fine control may not be possible. Finer hydraulic pressure control has been performed by controlling the hydraulic pressure of the engagement device by electrical means such as a linear solenoid valve or a duty solenoid valve. An example thereof is Japanese Patent Laid-Open No. 63-83442.
It is described in Japanese Patent Publication No.

[0010]

According to the so-called direct control in which the supply pressure to the friction engagement device is controlled by the above-mentioned solenoid valve, the degree of freedom in control is high, so that pressure adjustment suitable for various situations is performed. The shift shock can be improved. However, conventionally, the pressure adjustment in the case of simultaneously switching the clutch C0 and the brake B0 of the second transmission section 3 described above has been controlled by the synchronous rotation of the one-way clutch F0 or by using time as a parameter. That is, for example, when downshifting from the 5th speed to the 4th speed, the hydraulic pressure of the brake B0 is gradually reduced at a predetermined rate according to the vehicle speed and the throttle opening. As a result, the one-way clutch F
0 starts to rotate synchronously or when a predetermined time corresponding to the rate of decrease in hydraulic pressure elapses.
It is controlled to start the supply of hydraulic pressure.

Therefore, for example, when the vehicle is traveling at the 5th speed, the accelerator pedal is fully depressed, and accordingly, the 4th
When the downshift to the high speed is started and the accelerator pedal is released immediately after that (when the accelerator is turned off), the one-way clutch F0 does not rotate synchronously.
When the guard timer counts up for the specified time, the supply of hydraulic pressure to the clutch C0 is started. As described above, in the conventional shift control device that performs direct control, when the input torque to the automatic transmission becomes ambiguous due to continuous accelerator on and accelerator off for a short period of time, However, there is an inconvenience that the shift is not completed unless the time set by the guard timer elapses, and the shift is delayed.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a shift control device that does not cause a feeling of delay in shifting even when the input torque is ambiguous. It is a thing.

[0013]

The present invention is characterized in that it has the structure shown in FIG. 1 in order to achieve the above object. That is, according to the present invention, the power-on downshift in which the predetermined shift speed is downshifted to another shift speed as the input torque is increased, the first friction engagement device 21 is released and the second friction engagement device 21 is released. The shift control device of the automatic transmission A that engages and executes the engagement device 22 and directly adjusts the engagement hydraulic pressure of the first friction engagement device 21 by the electrically controlled pressure adjustment device 23. In the above, the shift detecting means 24 for detecting the power-on downshift and the rotation speed detecting means 2 for detecting the rotation speed of a predetermined rotating member whose rotation speed increases during the downshift.
5 and the first frictional engagement device 21 when the rotational acceleration of the rotary member becomes negative after the start of the downshift.
Releasing means 26 for controlling the pressure adjusting means 23 so that the second friction engaging device 22 is engaged simultaneously with or after releasing the first friction engaging device 21. And 27 are provided.

[0014]

In the automatic transmission A to which the present invention is applied, the first friction engagement device 21 is released and the second friction engagement device 22 is engaged during a predetermined power-on downshift. To be made. The engagement hydraulic pressure of the first frictional engagement device 21 is regulated by the electrically regulated pressure regulating means 23, and generally, the engagement hydraulic pressure is gradually reduced according to the status of the shift. When the power-on downshift is detected by the shift detecting means 24, the rotation speed detecting means 25 detects the rotation speed of the rotating member whose rotation speed increases during the downshift, and the rotation acceleration is detected. When it becomes negative, that is, when the rotational speed to be increased starts to decrease, the releasing means 26 controls the pressure adjusting means 23 to immediately release the first friction engagement device 21. Simultaneously with or after this, the engagement means 27 engages the second friction engagement device 22. Therefore, the downshift started in the power-on state is immediately completed when the power-off state is detected, and the shift is not delayed.

[0015]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 2 is a block diagram schematically showing an embodiment of the present invention, and the example shown here is directed to an automatic transmission provided with the gear train shown in FIG. Regarding the structure of the gear train, the same reference numerals as those in FIG.

Each clutch C0, C in the automatic transmission A
The hydraulic control device 30 that supplies and discharges hydraulic pressure to and from the brakes 1 and C2 and the brakes B0, B1, B2, and B3 includes first to third solenoid valves for mainly setting first to fifth speeds and reverse gear. S1, S2, S3, a linear solenoid valve SLU for controlling the lockup clutch 1 and adjusting the supply pressure of the brake B0, a linear solenoid valve SLT for controlling the line hydraulic pressure PL according to the throttle opening, A linear solenoid valve SLN for controlling the back pressure of the accumulator is provided. Electronic control unit (EC for controlling these solenoid valves
U) 31 is provided, which is mainly composed of a central processing unit (CPU), storage elements (ROM, RAM), and an input / output interface, and includes a throttle opening signal, a vehicle speed signal, and a pattern select signal. ,
An engine water temperature signal, a brake signal, and other signals are input, and based on these input signals and a map stored in advance, the gear stage to be set or the engagement / release of the lockup clutch 1, or The hydraulic pressure to be regulated is calculated and obtained, and each solenoid valve is controlled based on the calculation result. Further, a rotation speed sensor 32 for detecting the rotation speed of the clutch C0 in the second speed change section 3 among the rotation members constituting the gear train is provided, and this sensor 32 outputs a signal to the electronic control unit 31. .

As described above, the brake B of the second transmission section 3
The supply pressure of 0 is configured to be directly regulated by the linear solenoid valve SLU for the lockup clutch 1, and the supply pressure of the clutch C0 is configured to be regulated by an accumulator, and a hydraulic circuit therefor. FIG. 3 is a schematic diagram showing the configuration of the above. A shift valve 36 is provided which connects the line hydraulic oil passage 33 to the oil passage 34 for the brake B0 and the oil passage 35 for the clutch C0 so as to communicate with each other. The shift valve 36 supplies and discharges hydraulic pressure to and from a control port 37 thereof. The solenoid valve S3 is used. That is, when the third solenoid valve S3 is turned on, the hydraulic pressure is supplied to the control port 37 and the line hydraulic oil passage 33
To the oil passage 35 for the clutch, and conversely, when the third solenoid valve S3 is OFF, the control port 37
Is discharged from the line hydraulic oil passage 33 to the brake oil passage 3
It is designed to communicate with 4.

A control valve 38 having a pressure adjusting function is interposed in the brake oil passage 34, and the control valve 38 further adjusts the hydraulic pressure output from the modulator valve 39 by a linear solenoid valve SLU. The hydraulic pressure supplied to and discharged from the brake B0 is adjusted using the hydraulic pressure as a signal pressure. Also, the oil passage 35 for the clutch
The accumulator 40 is installed in the
The pressure is adjusted by an accumulator control valve 41 controlled by the linear solenoid valve SLN.

The engagement states of the clutch C0 and the brake B0 in the second speed change portion 3 are switched, for example, during the speed change between the fourth speed and the fifth speed. Engagement / release timings are not controlled to be the same, and control suitable for the input state is performed. As an example, FIG. 4 is a flowchart showing a control routine for downshifting from the fifth speed to the fourth speed. After the initial setting and data reading, the fifth to fourth speeds are set. It is determined whether or not the downshift is determined (step 1). If the downshift from the fifth speed to the fourth speed is determined, is the flag F set to "1" in step 2? Determine whether or not. This flag F indicates that the downshift from the 5th speed to the 4th speed is determined and the shift control is started.
If the determination result of step 2 is "no", step 3
At, the timer T is started. This is time t0 in the time chart of FIG. Further, in step 4 following step 3, the flag F is set to "1".

When the result of the determination in step 2 is "yes" and after the control in step 4 is executed, in step 5, the hydraulic pressure supplied to the clutch and brake is changed to a hydraulic pressure which is predetermined according to the throttle opening and the vehicle speed. Set. This hydraulic pressure is stored in advance as a map using the throttle opening and the vehicle speed as parameters. As a general tendency, the higher the hydraulic pressure, the higher the throttle opening and the faster the vehicle speed. ing. The hydraulic pressure of the brake B0 is set by, for example, duty-controlling the linear solenoid valve SLU. An example of this is shown in the time chart of FIG. 5, in which the duty ratio is increased to a predetermined value at time t0 when the downshift from the fifth speed to the fourth speed is determined, and thereafter, a predetermined slope is set. The duty ratio is gradually increased so that This is to prevent a sudden change in torque and the accompanying shift shock.

After setting the hydraulic pressure as described above, in step 6, it is judged from the throttle opening and the vehicle speed whether or not the power is off. If the result of the judgment is "no", the routine proceeds to step 7 where the rotational speed (NC0) of the clutch C0 is monitored. In the power-on state, the rotational speed of the clutch C0 gradually increases as the hydraulic pressure PB0 of the brake B0 decreases, and this can be shown by taking the time on the horizontal axis and the rotational speed on the vertical axis. It becomes a line rising to the right as in the time chart of. If the power-on state continues, the line showing the rotational speed NC0 of the clutch C0 will remain a line rising to the right, but the accelerator pedal may be suddenly returned depending on the road surface condition, that is, the power may be switched off. Therefore, at step 8, it is judged whether or not the line showing the rotational speed NC0 of the clutch C0 is sloping downward, that is, whether the angular acceleration of the clutch C0 is negative. The result of this step 8 is “yes”
If so, the process proceeds to step 9 to execute the power-off shift control.

This power-off shift control is, in short, a control for immediately setting the fourth speed. This will be explained with reference to the time chart of FIG. 5. The rotation speed NC0 of the clutch C0 begins to decrease. At the time point t1 when it is determined that the duty ratio of the linear solenoid valve SLU is maximized and the third solenoid valve S3 is turned on. As a result, the pressure regulation level of the control valve 38 is drastically lowered, and the shift valve 36 is switched to exhaust the pressure from the brake B0 and supply the line oil pressure PL toward the clutch C0. Therefore, the hydraulic pressure PB0 of the brake B0 is lowered as shown by the solid line and immediately released, and the hydraulic pressure PC0 of the clutch C0 is gradually increased as shown by the solid line to increase its torque capacity and the downshift of the second transmission portion 3 is performed. The shift is completed and the fourth speed is set.
That is, according to the above shift control device, the fifth speed to the fourth speed
When the power off state is started after the power-on / downshift to the high speed is started, the fourth speed is immediately set, and the output shaft torque becomes the negative torque at the time t2 when the clutch C0 reaches the predetermined torque capacity. As a result, the operator can feel the completion of the gear shift, and the feeling of delay in gear shift does not occur.

If the result of the determination in step 8 is "NO", that is, if the power-on state continues, the process proceeds to step 10 and it is determined whether or not the one-way clutch F0 is synchronized. If the result of the determination is "yes", the gear shift end control is executed in step 11. This shift end control is a control including control for turning on the first solenoid valve S1 after turning on the third solenoid valve S3. That is, when the rotational speed of the clutch C0 increases as shown by the alternate long and short dash line in FIG. 5 as the torque capacity of the brake B0 decreases, the one-way clutch F0 is finally engaged, whereby the fourth speed is set. A state in which the duty ratio of the linear solenoid valve SLU is maximized immediately before the time point t3, the third solenoid valve S3 is turned on immediately after the one-way clutch F0 is synchronized, and the shift valve 38 sets the fourth speed. Is switched to. After that, the linear solenoid valve SLU is used for controlling the lockup clutch 1, so the first solenoid valve SLU is used.
1 is turned on, and the hydraulic pressure of the linear solenoid valve SLU is supplied to the lockup clutch 1 accordingly.

If the result of the determination in step 9 is "no", the process proceeds to step 12 and it is determined whether or not the count time of the timer T exceeds a preset time α, and if it exceeds the time α. , The shift end control of step 11 is executed, and if the time is not exceeded, the control process returns. That is, in order to prevent a shift delay, if the fourth speed is not set within the set time α,
Simultaneously with the elapse of the set time α, the third solenoid valve S3 is turned on to switch the shift valve 36, and the shift to the fourth speed is executed. The change in the output shaft torque and the change in the hydraulic pressure in this case are shown by the alternate long and short dash line in FIG.

On the other hand, the fifth to fourth speeds in the power-off state
If it is a downshift to the high speed, the determination result of step 6 is "Yes", and in this case, the process immediately proceeds to step 9 to execute the above-described shift control to the fourth speed in the power off state. In addition, the judgment result of step 1 is "No"
In the case of, the process proceeds to step 13, the flag F is reset to zero, and the process returns.

For reference, the gear shift control in the case where the power-off gear shift control is not performed even if the rotational speed of the clutch C0 is lowered during gear shifting will be described below.
Since the hydraulic pressure PB0 of the brake B0 is basically smoothly decreased as shown by the one-dot chain line in FIG. 5, if the control is continued even in the power-off state, the time t2 at which the timer T counts up the set time α. Up to shift valve 3
Switching of 6 is delayed, and after that time t2, clutch C
Only when the oil pressure PC0 of 0 rises to a predetermined oil pressure, a negative torque appears in the output shaft torque as shown by the broken line in FIG. 5, and the rotational speed of the clutch C0 also increases as shown by the broken line. Therefore, it takes a long time before the completion of the shift is felt, which causes a delay in the shift.

In the above-described embodiment, the automatic transmission having the gear train shown in FIG. 2 has been described, but the present invention is an automatic transmission having a gear train other than the gear train shown in FIG. Can also be carried out for
It can also be applied to the case of downshifts other than the downshift from the fourth speed to the fourth speed. Further, in the above-described embodiment, the supply hydraulic pressure is directly controlled for one of the friction engagement devices involved in gear shifting. However, in the automatic transmission targeted by the present invention, all are controlled. Even if the hydraulic pressure supplied to the friction engagement device is directly controlled, the shift control can be performed in the same manner as described above.

[0028]

As is apparent from the above description, according to the shift control device of the present invention, when the power-off state is entered after the start of the power-on downshift shift control, the ambiguous state of the input torque is changed. Detected by the change in the rotation speed of the rotating member, the hydraulic pressure of the friction engagement device to be released in order to execute the downshift is immediately reduced to the released state, and the hydraulic pressure is applied to the friction engagement device to be engaged. Since the torque capacity is supplied to increase the torque capacity, it is possible to immediately eliminate the ambiguous state of the input torque due to the power-off state, and prevent the shift from being delayed.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing a basic configuration of the present invention.

FIG. 2 is a block diagram schematically showing an embodiment of the present invention.

FIG. 3 is a block diagram schematically showing a configuration of a hydraulic circuit section that controls a clutch and a brake in a second speed change section.

FIG. 4 is a flowchart showing a control routine for downshifting from fifth speed to fourth speed.

FIG. 5 is a time chart showing changes in clutch rotational speed and output shaft torque, duty ratio of linear solenoid valve, output of shift valve switching command signal, and hydraulic pressures of brake B0 and clutch C0.

FIG. 6 is a skeleton diagram showing an example of a gear train in which five forward gears and one reverse gear can be set.

7 is an operation table for setting each shift speed of the automatic transmission including the gear train shown in FIG.

[Description of Reference Signs] 21 first friction engagement device 22 second friction engagement device 23 pressure adjusting device 24 shift detecting means 25 for detecting 25 rotational speed detecting means 26 releasing means 27 engaging means A automatic transmission

Claims (1)

[Claims] 1. A power-on downshift for downshifting from a predetermined shift stage to another shift stage with an increase in input torque by releasing the first friction engagement device and the second friction engagement unit. In a shift control device for an automatic transmission, which executes a coupling device for engagement and directly adjusts an engagement hydraulic pressure of the first friction engagement device by an electrically controlled pressure adjusting device, Gear shift detecting means for detecting a downshift, rotation speed detecting means for detecting a rotation speed of a predetermined rotating member whose rotation speed increases during the downshift, and rotation acceleration of the rotating member after starting the downshift Release means for controlling the pressure adjusting device so that the first frictional engagement device immediately releases when the second frictional engagement device becomes negative, and the second frictional engagement device simultaneously with or after the release of the first frictional engagement device. friction That it comprises a engaging means for engaging the coupling device shift control device for an automatic transmission according to claim.