JPH08270780A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE: To accurately detect the stable state of a rotating speed change rate for the start of feedback control at the time of speed change. CONSTITUTION: A control device for an automatic transmission executes the speed change of the automatic transmission 2 connected to an engine 1 by increasing the engaging pressure of a specified friction engaging device 3, and performs the feedback control of the engaging pressure of the friction engaging device 3 so that the rotating speed of a specified rotary element 4 becomes the predetermined target rotating speed when the rotation change state of the rotary element 4 generated in association with the rise of the engaging pressure of the friction engaging device 3 becomes a specified stable state. This control device is provided with an output detecting means 5 for detecting the output of the engine 1, and a target stable state setting means 6 for setting a stable state according to engine output detected by the output detecting means 5.

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 in an automatic transmission of a vehicle, and more particularly to a control device for performing feedback control during a shift.

[0002]

2. Description of the Related Art A shock associated with a gear shift in an automatic transmission can be reduced by smoothly causing a rotational change. However, if the rotational change is slow, it takes a long time to complete the gear shift. Therefore, there is a feeling of delay in shifting. Therefore, in general, a target rotation change is set in advance, and the transfer torque capacity of the friction engagement device involved in gear shifting is controlled to change the rotation change such as the input speed as much as possible. I am trying to do it. As an example thereof, feedback control of engagement hydraulic pressure is performed on the friction engagement device. That is, after the gear change judgment is established and the gear change instruction is output, the friction engagement is performed so that the change in the input speed can be detected while the change in the input speed is detected in the inertia phase in which the change in the input speed or the like occurs. It controls the hydraulic pressure of the device.

Such feedback control is executed with the start of the inertia phase, but immediately after the start of the inertia phase, the change in rotation is not stable, so feedback control is performed based on the rotation speed detected at that time. If this is done, hunting occurs in the feedback control because the change in rotation speed becomes complicated.

Therefore, in the invention disclosed in Japanese Patent Laid-Open No. 2-80853, feedback control is prohibited during the unstable period of the rotational speed immediately after the start of the inertia phase, and the feedback control is executed after the rotational speed stabilizes. I have decided. Further, the determination of the stable state is made by the change rate of a predetermined number of revolutions such as the input number of revolutions being a predetermined value or less.

[0005]

In the above-mentioned conventional device that delays the feedback control of the friction engagement device at the time of shifting until the rotational speed of a predetermined rotary element such as the input rotational speed stabilizes, the engine drive state is increased. Therefore, there is a possibility that feedback control may be delayed or hunting may occur if this is prevented.

That is, when the torque down control is not performed during high output with a large throttle opening or during gear shifting, it is
The change rate of the input speed after the start of the inertia phase becomes large. Therefore, if the reference value of the rotational speed change rate for determining the stable state of the rotational speed is made small, the determination of the stable state is delayed, and eventually the start of the feedback control is delayed.
On the other hand, if the reference value of the rotational speed change rate for determining the stable state is set to a large value, the rotational speed will be relatively high immediately after the inertia phase starts when the engine output is low or when torque down control is executed. Even if there is a large change in the value, it is determined that the state is stable, and as a result, hunting may occur due to feedback control being executed even in the substantially unstable state.

The above-mentioned feedback control of the engagement pressure is
This is done by controlling the back pressure of the accumulator connected to the target friction engagement device.Therefore, the piston in the friction engagement device advances in advance by the hydraulic pressure determined by the characteristics of the accumulator, and from that state, the accumulator back While the pressure is feedback-controlled, the hydraulic pressure rises and the engagement pressure increases. However, when the engagement pressure is electrically controlled directly without using an accumulator, the hydraulic pressure condition in the friction engagement device at the start of feedback control is unknown, and therefore the increase in hydraulic pressure at the start of feedback control is low. It is general to prevent the shock due to the sudden increase in the engaging pressure. Therefore, if feedback control is executed in this type of so-called direct pressure control, the change in rotational speed immediately after the start of the inertia phase becomes slow, so the hydraulic pressure should be increased at this point in order to match the rotational speed change rate with the target value. As a result, the rotation speed change rate increases, and the engagement pressure is reduced to correct this, which eventually causes hunting.

Even in the case where the so-called direct pressure control is performed in this way, the situation of the change in the number of revolutions at the time of gear change changes according to the driving state of the engine, etc., so that the stable state immediately after the start of the inertia phase is judged. In the conventional device that uses a uniform determination standard, the feedback control delay and hunting cannot always be effectively corrected.

The present invention has been made in view of the above circumstances, and provides a control device capable of performing feedback control of the engagement pressure of a friction engagement device during a gear shift without causing delay or hunting. It is intended to be provided.

[0010]

In order to achieve the above object, the present invention, as shown in FIG. 1, changes the speed of an automatic transmission 2 connected to an engine 1 to a predetermined friction engagement device 3.
When the rotational change state of the predetermined rotary element 4 becomes a predetermined stable state due to the increase of the engagement pressure of the frictional engagement device 3, the rotary element 4 is executed. In an automatic transmission control device that feedback-controls the engagement pressure of the friction engagement device 3 so that the rotation speed of the engine becomes a predetermined target rotation speed, output detection means 5 that detects the output of the engine 1, A target stable state setting means 6 for setting the stable state according to the engine output detected by the output detection means 5 is provided.

The target stable state setting means 6 in this control device sets the target rotational speed change rate setting means 6 for setting the target rotational speed change rate of the rotating element 4 according to the engine output.
−1, and feedback control instruction means for executing the feedback control when the rotational speed change rate of the rotary element is approximate to the target rotational speed change rate set by the target rotational speed change rate setting means 6-1. 7 can also be provided.

The output detecting means 5 includes means for detecting the engine output based on the load of the engine 1, and the target revolution speed change rate setting means 6-1 sets the target revolution as the detected engine load increases. Means may be provided for setting the numerical rate of change to a large value.

Further, according to the present invention, a torque down instruction means 8 for selectively reducing the engine output at the time of gear shifting is further provided, and the target rotation speed change rate setting means 6-1 instructs the engine output reduction control at the time of gear shifting. It is possible to provide a means for setting the target rotation speed change rate in the case of being set to a value smaller than that in the case where the engine output reduction control is not instructed.

[0014]

In the automatic transmission 2 to which the present invention is applied, when the rotational change of the predetermined rotary element 4 during gear shifting becomes stable,
The engagement pressure of the friction engagement device 3 that is engaged to execute the shift is feedback-controlled. The stable state, which is a condition for starting the feedback control, is set by the target stable state setting means 6 according to the output of the engine 1 detected by the output detection means 5, and therefore, the predetermined rotating element 4 at the time of gear shifting is set. It is possible to accurately detect the stable state of the rotation change and to accurately execute the feedback control.

More specifically, the target stable state is set by the target rotational speed change rate setting means 6-1 as the target rotational speed change rate of the rotating element 4, and the rotational speed change rate of the rotating element 4 is the target. When the state becomes close to the rotation speed change rate, the feedback control instructing means 7 gives an instruction to start the feedback control.

The engine output for setting the target rotational speed change rate can be detected as an engine load based on the throttle opening degree and the like. When the engine load is large, the target rotation speed change rate is set to a large value. When the engine load is large, the change in the number of revolutions at the time of gear shift becomes large, so that the stable state of the change in the number of revolutions can be accurately determined.

Further, according to the present invention, the torque down instruction means 8 for reducing the engine torque at the time of shifting can be provided. In this case, if the engine torque reduction control is instructed, the target rotational speed change rate is set to a small value. To be done.
If the engine torque is small, the rotational speed change rate at the time of shifting is small, so that it is possible to determine the stable state accordingly, and delay or hunting of feedback control is prevented.

[0018]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 2 is an overall control system diagram showing an embodiment of the present invention. An engine E to which an automatic transmission A is connected has an intake pipe 12 in which a main throttle valve 13 is provided.
And a sub-throttle valve 14 located upstream thereof. The main throttle valve 13 is connected to an accelerator pedal 15 and is opened / closed according to the amount of depression of the accelerator pedal 15. The sub-throttle valve 14 is opened and closed by a motor 16. An engine electronic control unit (E-ECU) 17 for controlling the motor 16 for adjusting the opening of the sub-throttle valve 14 and for controlling the fuel injection amount and ignition timing of the engine E is provided. There is. The electronic control unit 17 is mainly composed of a central processing unit (CPU), a storage unit (RAM, ROM), and an input / output interface. The electronic control unit 17 stores data for control as Engine (E /
G) Various signals such as rotational speed N, intake air amount Q, intake air temperature, throttle opening, vehicle speed, engine water temperature, and signals from brake switches are input.

In the automatic transmission A, the hydraulic control device 18 controls gear shifting and lockup clutch, line pressure, or engagement pressure of a predetermined friction engagement device. The hydraulic control device 18 is configured to be electrically controlled, and also has first to third shift solenoid valves S1 to S3 for executing a shift and a first to third engine for controlling an engine braking state. 4 solenoid valve S4, linear solenoid valve SLT for controlling the line pressure, linear solenoid valve SLN for controlling the back pressure of the accumulator, linear for controlling the engagement pressure of a lock-up clutch or a predetermined friction engagement device A solenoid valve SLU is provided.

An electronic control unit (T-ECU) 19 for an automatic transmission that outputs a signal to these solenoid valves to control gear shift, line pressure, accumulator back pressure, etc.
Is provided. This automatic transmission electronic control unit 19
Is a central processing unit (CPU) and a storage device (RA
M, ROM) and an input / output interface, and the electronic control unit 19 has a throttle opening, vehicle speed, engine water temperature, a signal from a brake switch, a shift position, as data for control.
A signal from the pattern select switch, a signal from the overdrive switch, a signal from a C0 sensor for detecting the rotational speed of the clutch C0, which will be described later, an oil temperature of the automatic transmission,
Signals from the manual shift switch are input.

The electronic control unit 19 for the automatic transmission and the electronic control unit 17 for the engine are connected to each other so that data can be communicated with each other, and the electronic control unit 17 for the engine transfers to the electronic control unit 19 for the automatic transmission. On the other hand, a signal such as the intake air amount per rotation (Q / N) is transmitted, and an instruction signal for each solenoid valve is sent from the automatic transmission electronic control unit 19 to the engine electronic control unit 17. A signal equivalent to, a signal instructing a shift speed, and the like are transmitted.

That is, the electronic control unit 19 for the automatic transmission
Is based on the input data and the map stored in advance, and the ON / OFF of the gear position and the lockup clutch is performed.
F, or the line pressure or the adjustment level of the engagement pressure is judged, and based on the judgment result, an instruction signal is output to a predetermined solenoid valve, and further judgment of fail or control based on it is performed. . In addition to controlling the fuel injection amount, the ignition timing, the opening degree of the sub-throttle valve 14, etc. based on the input data, the electronic control unit 17 for the engine also sets the fuel injection amount during the shift in the automatic transmission A. The output torque is temporarily reduced by reducing the amount, changing the ignition timing, or narrowing the opening of the sub-throttle valve 14.

FIG. 3 is a diagram showing an example of a gear train of the above-described automatic transmission A, and in the configuration shown here, it is configured to set five forward gears and one reverse gear. That is, the automatic transmission A shown here is used in the torque converter 20.
And a sub-transmission unit 21 and a main transmission unit 22. The torque converter 20 includes a lockup clutch 23.
The lock-up clutch 23 has a front cover 25 that is integrated with the pump impeller 24.
A member (hub) in which the turbine runner 26 and the turbine runner 26 are integrally attached
It is provided between 7 and. An engine crankshaft (not shown) is connected to a front cover 25, and a turbine runner 26 is connected to an input shaft 28.
Is connected to a carrier 30 of an overdrive planetary gear mechanism 29 that constitutes the auxiliary transmission unit 21.

Carrier 3 in this planetary gear mechanism 29
A multi-plate clutch C0 and a one-way clutch F0 are provided between 0 and the sun gear 31. The one-way clutch F0 is engaged when the sun gear 31 rotates forward relative to the carrier 30 (rotates in the rotation direction of the input shaft 28). Further, a multi-plate brake B0 for selectively stopping the rotation of the sun gear 31 is provided.
The ring gear 3 which is an output element of the subtransmission unit 21
2 is connected to an intermediate shaft 33 which is an input element of the main transmission unit 22.

Therefore, in the sub-transmission unit 21, the entire planetary gear mechanism 29 rotates integrally when the multi-plate clutch C0 or the one-way clutch F0 is engaged, so that the intermediate shaft 33 has the same speed as the input shaft 28. It will rotate at low speed. Further, in the state where the brake B0 is engaged and the rotation of the sun gear 31 is stopped, the ring gear 32 is accelerated with respect to the input shaft 28 to rotate in the normal direction, and the high speed stage is established.

On the other hand, the main transmission section 22 is provided with three sets of planetary gear mechanisms 40, 50, 60, and their rotating elements are connected as follows. That is, the sun gear 41 of the first planetary gear mechanism 40 and the sun gear 51 of the second planetary gear mechanism 50 are integrally connected to each other, and the ring gear 43 of the first planetary gear mechanism 40 and the carrier 52 of the second planetary gear mechanism 50 are connected. The third planetary gear mechanism 60 and a carrier 62 are coupled to each other, and the carrier 62 is coupled to an output shaft 65. Further, the ring gear 53 of the second planetary gear mechanism 50 is connected to the sun gear 61 of the third planetary gear mechanism 60.

In the gear train of the main transmission unit 22, it is possible to set a reverse gear and four gears on the forward side, and a clutch and a brake for that purpose are provided as follows. First, the clutch will be described. The ring gear 53 and the third gear of the second planetary gear mechanism 50 which are connected to each other.
A first clutch C1 is provided between the sun gear 61 of the planetary gear mechanism 60 and the intermediate shaft 33, and the sun gear 41 of the first planetary gear mechanism 40 and the sun gear 51 and the intermediate shaft of the second planetary gear mechanism 50 are connected to each other. A second clutch C2 is provided between the first clutch 33 and the second clutch C3.

Next, the brake will be described. The first brake B1 is a band brake, and the sun gears 41 and 5 of the first planetary gear mechanism 40 and the second planetary gear mechanism 50 are used.
It is arranged to stop the rotation of 1. A first one-way clutch F1 and a second brake B2, which is a multi-disc brake, are arranged in series between the sun gears 41 and 51 (that is, the common sun gear shaft) and the casing 66. One way clutch F1 is sun gear 41,5
1 engages when trying to rotate in the reverse direction (rotation in the direction opposite to the rotation direction of the input shaft 28). The third brake B3, which is a multi-disc brake, is the first planetary gear mechanism 4
It is provided between the zero carrier 42 and the casing 66. Then, as a brake for stopping the rotation of the ring gear 63 of the third planetary gear mechanism 60, the fourth brake B4, which is a multi-disc brake, and the second one-way clutch F2 are provided in the casing 6.
6 and 6 are arranged in parallel. The second one-way clutch F2 is adapted to be engaged when the ring gear 63 tries to rotate in the reverse direction.

In the above-described automatic transmission A, it is possible to set five forward speeds and one reverse speed by engaging and disengaging each clutch and brake as shown in the operation table of FIG. In FIG. 4, a circle indicates an engaged state, a circle indicates an engaged state during engine braking, a triangle indicates either engaged or disengaged, and a blank indicates a disengaged state.

As shown in the operation table of FIG. 4, the second
To change the speed between the third speed and the third speed, a clutch that changes the engaged / released states of the second brake B2 and the third brake B3 together.
Toe clutch shift. In order to smoothly perform this shift, the hydraulic circuit shown in FIG. 5 is incorporated in the hydraulic control device 18 described above.

In FIG. 5, reference numeral 70 indicates a 1-2 shift valve, reference numeral 71 indicates a 2-3 shift valve, and reference numeral 72 indicates a 3-4 shift valve. The communication state of each port of the shift valves 70, 71, 72 at each shift speed is determined by the respective shift valves 70, 71, 7
As shown on the lower side of No. 2. In addition, the number shows each gear stage. A third brake B3 is connected via an oil passage 75 to a brake port 74 that communicates with the input port 73 at the first speed and the second speed among the ports of the 2-3 shift valve 71. An orifice 76 is provided in this oil passage, and the orifice 76 and the third brake B3
A damper valve 77 is connected between and. The damper valve 77 sucks a small amount of hydraulic pressure to perform a buffering action when the line pressure is suddenly supplied to the third brake B3.

Reference numeral 78 is a B-3 control valve, and the engagement pressure of the third brake B3 is directly controlled by this B-3 control valve 78. That is, the B-3 control valve 78 includes a spool 79, a plunger 80, and a spring 81 interposed therebetween, and an oil passage 75 is connected to an input port 82 opened and closed by the spool 79. Output port 8 that is selectively communicated with input port 82
3 is connected to the third brake B3. Further, the output port 83 is connected to a feedback port 84 formed on the tip side of the spool 79. On the other hand, in the port 85 that opens at the location where the spring 81 is arranged, the port 86 that outputs the D range pressure at the third or higher speed of the 2-3 shift valve 71 is connected via the oil passage 87. It is in communication. A lockup clutch linear solenoid valve SLU is connected to a control port 88 formed on the end side of the plunger 80.

Therefore, the B-3 control valve 78
Is configured such that the pressure regulation level is set by the elastic force of the spring 81 and the hydraulic pressure supplied to the port 85, and the elastic force of the spring 81 increases as the signal pressure supplied to the control port 88 increases. There is.

Further, reference numeral 89 in FIG. 5 denotes a 2-3 timing valve. The 2-3 timing valve 89 has a spool 9 having a small diameter land and two large diameter lands.
0, the first plunger 91, the spring 92 arranged between them, and the spool 90, and the first plunger 9
1 and a second plunger 93 arranged on the opposite side. An oil passage 95 is connected to an intermediate port 94 of the 2-3 timing valve 89, and this oil passage 95 is
Of the ports of the 2-3 shift valve 71, the port 96 is connected to the port 96 that is communicated with the brake port 74 at the shift speed of the third speed or higher.

Further, the oil passage 95 is branched midway to open a port 97 between the small-diameter land and the large-diameter land.
Is connected via an orifice. The port 98, which is selectively communicated with the port 94 at the intermediate portion, is the oil passage 9
It is connected to the solenoid relay valve 100 via 9. The lock-up clutch linear solenoid valve SLU is connected to the port opened at the end of the first plunger 91, and the second brake B2 is passed through the orifice at the port opened at the end of the second plunger 93. Connected.

The oil passage 87 is for supplying / discharging hydraulic pressure to / from the second brake B2, and a small diameter orifice 101 and an orifice 102 with a check ball are interposed in the middle thereof. Further, the oil passage 103 branched from the oil passage 87 has a large diameter orifice 10 provided with a check ball that opens when the pressure is exhausted from the second brake B2.
4 is interposed, and this oil passage 103 is connected to an orifice control valve 105 described below.

The orifice control valve 105 is a valve for controlling the exhaust pressure speed from the second brake B2, and the port 107 formed in the intermediate portion so as to be opened and closed by the spool 106 has the second brake B2.
The oil passage 103 is connected to a port 108 formed below the port 107 in the figure. A port 109 formed above the port 107 to which the second brake B2 is connected in the drawing is a port that is selectively communicated with the drain port, and the port 109 is connected to the port 109 via an oil passage 110. The port 111 of the B-3 control valve 78 is connected. The port 111 is a port that is selectively communicated with the output port 83 to which the third brake B3 is connected.

Of the ports of the orifice control valve 105, a control port 112 formed at the end opposite to the spring for pressing the spool 106 is connected to the port 114 of the 3-4 shift valve 72 through the oil passage 113. ing. This port 114 outputs the signal pressure of the third solenoid valve S3 at the shift speed of the third speed or lower, and the fourth speed.
It is a port for outputting the signal pressure of the fourth solenoid valve S4 at a shift speed higher than the high speed. Further, an oil passage 115 branched from the oil passage 95 is connected to the orifice control valve 105, and the oil passage 115 is selectively connected to the drain port.

Incidentally, the port 11 for outputting the D range pressure at the shift speed of the second speed or lower in the 2-3 shift valve 71.
6 through the oil passage 11 at the port 117 opening at the position where the spring 92 is arranged in the 2-3 timing valve 89.
8 are connected. Also 3-4 shift valve 72
Of these, a port 119, which is communicated with the oil passage 87 at a speed lower than the third speed, is connected to the solenoid relay valve 100 via an oil passage 120.

In FIG. 5, reference numeral 121 denotes an accumulator for the second brake B2, to the back pressure chamber of which the accumulator control pressure adjusted according to the hydraulic pressure output by the linear solenoid valve SLN is supplied. There is. The accumulator control pressure is configured to be higher as the output pressure of the linear solenoid valve SLN is lower. Therefore, the second brake B
The transitional hydraulic pressure of engagement / disengagement 2 is changed to a higher pressure as the signal pressure of the linear solenoid valve SLN is lower.

Reference numeral 122 indicates a C-0 exhaust valve, and reference numeral 123 indicates an accumulator for the clutch C0. C-0 exhaust valve 1
Numeral 22 operates to engage the clutch C0 to apply the engine brake only in the second speed in the second speed range.

Therefore, according to the hydraulic circuit described above,
If the port 111 of the B-3 control valve 78 communicates with the drain, the engagement pressure of the third brake B3 can be directly regulated by the B-3 control valve 78, and the regulation level can be adjusted by the linear solenoid valve. SLU
Can be changed by If the spool 106 of the orifice control valve 105 is in the position shown in the left half of the figure, the second brake B2 can be communicated with the oil passage 103 through this orifice control valve 105, so that the large diameter orifice 104 is used. Exhaust pressure is possible and therefore the drain speed from the second brake B2 can be controlled.

As shown in the above hydraulic circuit, the third brake B3 is not provided with an accumulator, and its engagement pressure is controlled by controlling the pressure adjustment level of the B-3 control valve 78 by the linear solenoid valve SLU. Controlled. The upshift from the first speed to the second speed, for example, of the shifts for engaging the third brake B3 is set by engaging the one-way clutch F2 in the first speed, and thus the third brake is engaged. This is done by engaging B3.

In this case, the engagement pressure of the third brake B3, that is, the hydraulic pressure supplied to the third brake B3 due to the shift output is first determined between the friction plates and between the pistons and the friction plates of the hydraulic servo mechanism. The third brake B3 is gradually increased to have a torque capacity by reducing the clearance between the third brake B3 and the third brake B3. Specifically, the duty ratio of the linear solenoid valve SLU is controlled. That is, the initial hydraulic pressure control is executed. Then, the inertia phase in which the rotational speed of a predetermined rotating element such as the input rotational speed NC0 (rotary speed of the turbine runner or the rotational speed of a member integrated with the turbine runner) changes in synchronization with the rotational speed of the second speed after shifting. After starting, the engagement pressure of the third brake B3 is feedback-controlled so that the rotational speed change rate becomes the target change rate.

This feedback control is a control for detecting the rate of change of a predetermined number of revolutions, for example, the input number of revolutions, and controlling the hydraulic pressure so that the rate of change agrees with the target value. It will be started later. Therefore, the control device of the present invention controls as shown in FIG.

FIG. 6 schematically shows a control routine for executing feedback control at the time of upshifting from the first speed to the second speed. First, at step 1, the speed is changed from the first speed to the second speed. It is determined whether or not the shift control is being performed. If the upshift from the first speed to the second speed is not being controlled, the routine returns. If the upshift from the first speed to the second speed is being controlled, it is determined whether or not the initial hydraulic pressure control is completed. (Step 2).

This initial hydraulic pressure control is executed in the third brake B3 executed in the torque phase after the shift output as described above.
The control of the engagement pressure is performed and is ended when the start of the inertia phase is determined. Therefore, if the judgment result in step 2 is "no", the process returns to step 1,
If the initial hydraulic pressure control is completed, the third brake B3
The engagement pressure PB3 of is swept up (step 3). Specifically, the duty ratio D _SLU of the linear solenoid valve SLU is increased by a constant value at regular time intervals (D
_SLU = D _SLU + ΔD _SLU ).

Next, the duration of this sweep-up is judged (step 4). If the duration has not passed the preset time, the process returns to step 1 and if the preset time has passed. It is determined whether or not the throttle opening has changed (step 5). That is, since the input rotation speed is not stable immediately after the start of the inertia phase, the engagement pressure PB3 of the third brake B3 is increased at a constant rate for a predetermined time.
If the throttle opening changes due to depression of the accelerator pedal or the like, the premise of the feedback control is broken, so it is determined in step 5 whether the throttle opening has changed.

When the throttle opening changes,
The routine shown in FIG. 6 is exited and the routine corresponding thereto is advanced. If the throttle opening has not changed,
It is determined whether or not the engine torque reduction control is being performed (step 6). The engine torque down control is a control executed to reduce the torque applied to the friction engagement device at the time of gear shifting to improve the gear shift shock, but the torque down control is performed because the engine is not warmed up sufficiently. May be prohibited, in which case the result of the determination in step 6 is "no". On the contrary, if the torque down control is executed as usual, the determination result of step 6 is "yes".

If the result of the determination in step 6 is "no" because the torque down control is not executed, the process proceeds to step 7 and the rate of change of the input speed is a predetermined reference value α.
Determine if less than. Here, the change rate of the input speed is
It is a value (difference) obtained by subtracting the difference between the input rotation speed and the target rotation speed at a predetermined time from the difference between the input rotation speed and the target rotation speed at the next time. The reference value α is a value indicating the upper limit value of the allowable range of the target rotation speed change rate. Therefore, if the rate of change of the input rotation speed is equal to or higher than this reference value, it is determined that the input rotation speed does not show the necessary and sufficient decreasing tendency toward the second speed synchronous rotation speed, so-called an unstable state. Return to 1. On the other hand, the change rate of the input speed is the reference value α
If less, that is, if the result of the determination in step 7 is "yes", feedback control of the engagement pressure of the third brake B3 is started (step 8). Specifically, based on the input rotation speed or based on the difference between the input rotation speed and the target rotation speed, the input rotation speed is reduced toward the second speed synchronous rotation speed with a target gradient. The duty ratio of the linear solenoid valve SLU is controlled.

On the other hand, when the torque down control during shifting is being executed and the result of the determination in step 6 is "yes", it is determined whether or not the rate of change of the input speed is less than another reference value β. (Step 9). The reference value β is a reference value that is set in response to the torque down control being executed and the input torque to the automatic transmission A being reduced, and is used when the torque down control is not performed. The value is smaller than the reference value α (<α).

Therefore, if the input rotation speed is equal to or higher than the reference value β, it means that the input rotation speed does not show the necessary and sufficient decrease tendency toward the second speed synchronous rotation speed. Return to. On the other hand, if the input speed is less than the reference value β, the process proceeds to step 8 and the third brake B
The feedback control of the engagement pressure of 3 is started.

The reference values α and β are set to different values depending on the presence / absence of torque down control, but they are set to different values depending on the magnitude of the throttle opening. . This is illustrated as a map in FIG. That is, the reference values α and β are set to larger values as the throttle opening θ increases.

Therefore, according to the above control device, when the input torque is large, a large reference value is adopted as the target rotational speed change rate for judging the stable state of the rotational speed change immediately after the start of the inertia phase. Therefore, even if the rotation speed change rate increases due to the large input torque, this can be determined to be a stable state, and therefore the start of the feedback control is not delayed. Even if the feedback control is started in this state, the input rotation speed changes greatly with the large input torque.
Hunting does not occur because it is not in an unstable state.

On the other hand, when the input torque is small,
Since a small reference value is adopted as the target rotation speed change rate for judging the stable state of the change in rotation speed immediately after the start of the inertia phase, the input value is input despite the unstable state due to the small input torque. The feedback control is not started when the state in which the rate of change of the rotational speed is small is determined to be a stable state, and as a result, hunting can be prevented.

In the above embodiment, the control device for the automatic transmission having the gear train shown in FIG. 3 and the hydraulic circuit shown in FIG. 5 has been described as an example, but the present invention is embodied as described above. The present invention is not limited to the example, and can be applied to a control device for an automatic transmission having another gear train or a hydraulic circuit. Therefore, the control described above is not limited to the control for the third brake, and is not limited to the control for the upshift from the first speed to the second speed. Further, the object of detection of the rotation speed when performing the feedback control is not limited to the input rotation speed, and an appropriate rotation speed of the rotating element can be adopted as necessary.

[0057]

As described above, according to the control device of the present invention, the determination of the stable state of the rotational speed change rate as the condition for starting the feedback control of the engagement pressure of the predetermined friction engagement device at the time of gear shift. Is configured so that the reference value is changed according to the output state of the engine, more specifically, the output torque, so that a small speed change rate in the low output state is misidentified as a stable state and feedback control is performed. It is possible to prevent delay in feedback control by deciding this as an unstable state when hunting is started and hunting occurs, or conversely because the output is high and the rate of change in rotation speed is large. .

[Brief description of drawings]

FIG. 1 is a block diagram showing the present invention by functional means.

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

FIG. 3 is a diagram mainly showing a gear train of the automatic transmission.

FIG. 4 is a diagram showing an operation table for setting each shift speed.

FIG. 5 is a diagram showing a part of a hydraulic circuit.

FIG. 6 is a flowchart schematically showing a feedback control start control routine at the time of an upshift from the first speed to the second speed.

FIG. 7 is a diagram showing a tendency of magnitude of a reference value for determining a rate of change in input rotational speed depending on a throttle opening.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 engine 2 automatic transmission 3 friction engagement device 4 rotating element 5 output detection means 6 target stable state setting means 6-1 target rotation speed change rate setting means 7 feedback control instruction means 8 torque down instruction means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F16H 59:38

Claims (4)

[Claims] 1. A shift of an automatic transmission connected to an engine is executed by increasing an engagement pressure of a predetermined friction engagement device, and a predetermined shift is performed according to an increase of the engagement pressure of the friction engagement device. An automatic transmission that feedback-controls the engagement pressure of the friction engagement device so that the rotational speed of the rotary element reaches a predetermined target rotational speed when the rotational change state of the rotary element reaches a predetermined stable state. In the control device, the output detection means for detecting the output of the engine, and the target stable state setting means for setting the stable state according to the engine output detected by the output detection means are provided. Control device for automatic transmission. 2. The target stable state setting means includes a target rotational speed change rate setting means for setting a target rotational speed change rate of the rotating element according to an engine output, and the rotational speed change rate of the rotating element is The control device for an automatic transmission according to claim 1, further comprising feedback control instruction means for executing the feedback control when the target rotation speed change rate set by the target rotation speed change rate setting means is approximated. 3. The output detecting means includes means for detecting an engine output based on an engine load, and the target rotation speed change rate setting means sets the target rotation speed change rate as the detected engine load increases. The control device for an automatic transmission according to claim 2, further comprising means for setting a large value. 4. A torque down instruction means for selectively reducing an engine output during a gear shift is further provided, wherein the target rotation speed change rate setting means is a target rotation when an instruction to reduce engine output during a gear shift is instructed. 3. The control device for an automatic transmission according to claim 2, further comprising means for setting the numerical change rate to a value smaller than that when the engine output reduction control is not instructed.