JP3259598B2 - Transmission control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling a shift of an automatic transmission for a vehicle.

[0002]

2. Description of the Related Art As is well known, a shift of an automatic transmission for a vehicle is executed by switching an engagement / disengagement state of a friction engagement device such as a clutch or a brake to change a power transmission path. In this case, since rotation fluctuations and torque fluctuations are involved, control is performed such that the friction engagement device is engaged or disengaged so that the rotation fluctuations and the torque fluctuations become smooth within a range where the achievement of the shift is not excessively slow. I have.

For example, JP-A-6-341525 discloses an automatic transmission for performing a clutch-to-clutch shift. In this automatic transmission, for example, a downshift from a third speed to a second speed is performed. , Release the second brake,
This is achieved by engaging the third brake. During this shift, rotation fluctuations occur according to the torque capacities of these two brakes. However, the driving force input to the automatic transmission is opposite between when the power is turned on and when the power is turned off. In order to perform a shift without causing a shock, it is necessary to perform different shift controls between power-on and power-off.

For example, in the case of a clutch-to-clutch shift from the third speed to the second speed, it is necessary to increase the input speed from the third speed synchronous speed to the second speed synchronous speed. If it is in the ON state, the torque capacity of the brake (second brake) for which the third speed is set is reduced to increase the input speed toward the second speed synchronous speed, and then the second speed is set. Is controlled so as to increase the torque capacity of the brake (third brake). On the other hand, in the power-off state, since the input rotation speed tends to decrease, the torque capacity of the brake (third brake) for setting the second speed is increased to increase the input rotation speed. Control.

[0005]

As described above, when the power is turned on and when the power is turned off, the direction of the torque input to the automatic transmission is opposite, so that the content of the shift control is naturally different. . However, the power-on state and the power-off state of the automatic transmission cannot always be clearly distinguished. If only one of the two types of shift control described above is executed, the shift shock deteriorates. There is a possibility of.

That is, the power-on state is a state in which power is acting on the automatic transmission in a direction to increase the input rotation speed, and the power-off state is a state in which power is input from the engine to the automatic transmission. Even if there is, the input rotation speed does not increase. Therefore, even if the engine is outputting when the throttle valve of the engine is opened, it cannot always be said that the engine is in the power-on state, and is uniquely determined as either the power-on state or the power-off state depending on the throttle opening and the vehicle speed. It may not be possible.

That is, the load on the automatic transmission and the engine differs depending on the external load applied to the vehicle, the resistance inherent to the vehicle itself, or the state of its change with time, and the output characteristics of the engine vary considerably. Even if the throttle opening is set to a predetermined value and the engine outputs, the automatic transmission may be in a non-driving state, and conversely, even if the throttle opening is relatively small, automatic transmission Machine may be running. In this way, the differences in the vehicle and the external load are affected by the drive of the automatic transmission.
In a state that greatly affects the non-drive state,
This is a so-called ambiguous state in which the OFF cannot be uniquely determined. Further, a similar situation occurs when the throttle opening slightly changes when the vehicle is in the boundary region between the power-on state and the power-off state.

On the other hand, in the prior art, the drive state of the automatic transmission is determined to be either the power-on state or the power-off state, and the shift control is performed in accordance with the determined drive state. In the ambiguous state (intermediate range), the content of the shift control becomes incompatible with the drive / non-drive state of the automatic transmission, and abrupt rotation fluctuation occurs to deteriorate the transmission shock, or conversely, rotation fluctuation progresses Without this, there is a risk that a shift delay may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and a shift control that can more effectively prevent a shift shock and a shift delay by performing a shift control in accordance with a driving state of an automatic transmission. It is intended to provide a device.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention determines not only the driving and non-driving states of an automatic transmission, but also the intermediate state thereof, and adjusts the results according to the judgment result. The present invention is characterized in that a shift control is performed.

More specifically, according to the present invention, the shift control from the first gear to the second gear is performed in a driving state in which the automatic transmission is driven and a non-driving state in which the automatic transmission is not driven. In a shift control device for an automatic transmission to be varied, an intermediate state determining means for determining an intermediate state between a driving state and a non-driving state of the automatic transmission; and An intermediate shift control executing means for executing still another shift control different from the shift control in the driving state and the shift control in the non-driving state is provided.

Further, in the present invention, the intermediate shift control executing means may determine a tendency of a change in the engagement pressure of a predetermined friction engagement device involved in shifting from the first shift speed to the second shift speed. A configuration may be provided that includes means for controlling a change tendency between the change tendency in the driving state and the change tendency in the non-drive state.

[0013]

The shift control device according to the present invention is adapted to switch between a predetermined first gear and a second gear, when the automatic transmission is in a driving state in which the input speed is increased, and in a non-driving state. Different shift control is performed in a certain case. As an example, if the engagement pressure of the friction engagement device involved in the shift is rapidly changed in the drive state, it is changed slowly in the non-drive state. In the transmission control device according to the present invention, the intermediate state determining means determines an intermediate state between the driving state and the non-driving state of the automatic transmission, that is, an intermediate state in which the determination of driving / non-driving cannot be clearly performed. . When the intermediate state is determined, the intermediate shift control execution means controls the above-described shift in a manner different from the control in the driving state and the control in the non-driving state. For example, when controlling the friction engagement device in the driving state and the non-driving state as described above, in the intermediate state, the change tendency of the engagement pressure of the friction engagement device is:
The engagement pressure of the friction engagement device is controlled so as to have a change tendency between the drive state and the non-drive state. Therefore, the content of the shift control is
Since the state is determined according to the non-driving state or an intermediate state, deterioration of the shift shock and delay of the shift can be avoided.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. The following example is an example in which the present invention is applied to an automatic transmission described in the above-mentioned Japanese Patent Application Laid-Open No. 6-341525.

In FIG. 1, an engine E to which an automatic transmission A is connected has a main throttle valve 13 in an intake pipe 12 thereof and a sub-throttle valve 14 located upstream of the main throttle valve 13. Its main throttle valve 1
Reference numeral 3 is connected to an accelerator pedal 15 and is opened and 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 to adjust the opening of the sub-throttle valve 14 and controlling the fuel injection amount and ignition timing of the engine E is provided. I have. The electronic control unit 17 includes a central processing unit (C
PU), a storage device (RAM, ROM) and an input / output interface. The electronic control unit 17 stores engine (E / G) rotation speed N, intake air Various signals such as the amount Q, intake air temperature, throttle opening, vehicle speed, engine water temperature, and signals from a brake switch are input.

In the automatic transmission A, the hydraulic pressure control device 18 controls the speed change and the lock-up clutch, the line pressure, or the engagement pressure of a predetermined friction engagement device. The hydraulic control device 18 is configured to be electrically controlled, has first to third shift solenoid valves S1,..., S3 for performing a shift, and has a first for controlling an engine brake state. 4 solenoid valve S4, linear solenoid valve SLT for controlling line pressure, linear solenoid valve SLN for controlling accumulator back pressure, linear for controlling 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 for outputting a signal to these solenoid valves to control a shift, a line pressure or an accumulator back pressure.
Is provided. This electronic control unit for automatic transmission 19
Is a central processing unit (CPU) and a storage device (RA
M, ROM) and an input / output interface, and this electronic control unit 19 shows throttle opening, vehicle speed, engine water temperature, signals from a brake switch, and shift position as data for control. Signal, signal from the pattern select switch, signal from the overdrive switch, clutch C
A signal from a C0 sensor for detecting a rotation speed of 0, an oil temperature of an automatic transmission, a signal from a manual shift switch, and the like 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 as to be able to perform data communication, and the electronic control unit 17 for the engine is connected to the electronic control unit 19 for the automatic transmission. Signals such as the amount of intake air per revolution (Q / N) are transmitted to the electronic control unit 19 for the automatic transmission and the electronic control unit 17 for the engine. And a signal instructing a gear position are transmitted.

That is, the electronic control unit 19 for the automatic transmission.
Is based on input data and a map stored in advance, and indicates ON / OF of a gear position and a lock-up clutch.
F, or the pressure regulation level of the line pressure or the engagement pressure is determined, and an instruction signal is output to a predetermined solenoid valve based on the result of the determination, and further, a failure determination and control based on the failure are performed. . The engine electronic control unit 17 controls the fuel injection amount, the ignition timing, the opening of the sub-throttle valve 14 and the like based on the input data, and also controls the fuel injection amount at the time of shifting in the automatic transmission A. The output torque is temporarily reduced by reducing the ignition timing, changing the ignition timing, or reducing the opening of the sub-throttle valve 14.

FIG. 2 is a diagram showing an example of the gear train of the automatic transmission A. In the configuration shown here, five forward speeds and one reverse speed are set. That is, the automatic transmission A shown here is
, A sub transmission unit 21 and a main transmission unit 22. The torque converter 20 includes a lock-up clutch 23
The lock-up clutch 23 has a front cover 25 integrated with the pump impeller 24.
(Hub) 2 integrally mounted with the turbine runner 26
7 is provided. An engine crankshaft (each not shown) is connected to a front cover 25 and an input shaft 28 to which a turbine runner 26 is connected.
Is connected to the carrier 30 of the overdrive planetary gear mechanism 29 that constitutes the subtransmission portion 21.

The carrier 3 in this planetary gear mechanism 29
A multi-plate clutch C0 and a one-way clutch F0 are provided between the first gear 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 (rotation in the rotation direction of the input shaft 28). A multi-disc 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 portion 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 portion 21, the entire planetary gear mechanism 29 rotates integrally with the multi-plate clutch C0 or the one-way clutch F0 in the engaged state, so that the intermediate shaft 33 has the same speed as the input shaft 28. At low speed. When the brake B0 is engaged and the rotation of the sun gear 31 is stopped, the speed of the ring gear 32 is increased with respect to the input shaft 28 and the ring gear 32 is rotated forward, so that a high gear is established.

On the other hand, the main transmission section 22 includes three sets of planetary gear mechanisms 40, 50, and 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 to each other. The three members of the third planetary gear mechanism 60 and the carrier 62 are connected, and the output shaft 65 is connected to the carrier 62. 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 section 22, a reverse gear and four forward gears can be set, and clutches and brakes for this are provided as follows. First, the clutch will be described. The ring gear 53 of the second planetary gear mechanism 50 and the third gear
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 of the second planetary gear mechanism 50 and the intermediate shaft are connected to each other. A second clutch C2 is provided between the clutch 33 and the second clutch C2.

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.
1 is arranged to stop rotation. A first one-way clutch F1 and a second brake B2, which is a multi-plate 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 has sun gears 41 and 5
1 is engaged when it is about to rotate in the reverse direction (rotation in the direction opposite to the rotation direction of the input shaft 28).

The third brake B 3, which is a multi-plate brake, is provided between the carrier 42 of the first planetary gear mechanism 40 and the casing 66. As a brake for stopping the rotation of the ring gear 63 of the third planetary gear mechanism 60, a fourth brake B4, which is a multi-plate brake, and a second one-way clutch F2.
Are arranged in parallel with the casing 66. The second one-way clutch F2 is adapted to be engaged when the ring gear 63 is about to rotate in the reverse direction.

In the above-mentioned automatic transmission A, five forward speeds and one reverse speed can be set by engaging and disengaging the clutches and brakes as shown in the operation chart of FIG. In FIG. 3, a mark 係 合 indicates an engaged state, a mark 時 に indicates an engaged state during engine braking, and a blank indicates a released state.

As shown in the operation table of FIG.
The shift between the third speed and the third speed is performed by a clutch that changes both the engaged and released states of the second brake B2 and the third brake B3.
Two-to-clutch speed change. In order to smoothly perform this shift, a hydraulic circuit shown in FIG. 4 is incorporated in the hydraulic control device 18 described above.

In FIG. 4, 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 these shift valves 70, 71, 72 at each shift speed is determined by the respective shift valves 70, 71, 7
2 as shown below. The numbers indicate the respective gears.

A third brake B 3 is connected through an oil passage 75 to a brake port 74 communicating 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 interposed in this oil passage, and a damper valve 77 is connected between the orifice 76 and the third brake B3. This damper valve 77 absorbs a small amount of hydraulic pressure when the line pressure is rapidly supplied to the third brake B3 to perform a buffering action.

Reference numeral 78 denotes a B-3 control valve, and the engagement pressure of the third brake B3 is directly controlled by the 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 selectively connected to 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 distal end side of the spool 79.

On the other hand, among the ports 85 of the 2-3 shift valve 71, a port 86 for outputting the D range pressure at the third or higher speed is connected to an oil passage 87. Are communicated through. The control port 88 formed on the end of the plunger 80 includes:
The lock-up clutch linear solenoid valve SLU is connected.

Therefore, the B-3 control valve 78
The pressure adjustment 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. I have.

In FIG. 4, reference numeral 89 denotes a 2-3 timing valve. The 2-3 timing valve 89 is a spool 9 having a small-diameter land and two large-diameter lands.
0 and a first plunger 91, and a first plunger 9 with a spring 92 and a spool 90 interposed therebetween.
1 and a second plunger 93 arranged on the opposite side. An oil passage 95 is connected to a port 94 at an intermediate portion of the 2-3 timing valve 89, and the oil passage 95
Of the ports of the 2-3 shift valve 71, it is connected to a port 96 which is communicated with the brake port 74 at the third or higher speed.

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

The oil passage 87 is for supplying and discharging hydraulic pressure to and 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. The oil passage 103 branched from the oil passage 87 has a large-diameter orifice 10 having a check ball which opens when the pressure is released from the second brake B2.
The oil passage 103 is connected to an orifice control valve 105 described below.

The orifice control valve 105 is a valve for controlling the speed of the pressure reduction from the second brake B2.
The oil passage 103 is connected to a port 108 formed below the port 107 in the figure.

Port 1 to which the second brake B2 is connected
The port 109 formed on the upper side in FIG. 7 is a port selectively connected to the drain port. The port 109 is connected to the port 111 of the B-3 control valve 78 via an oil passage 110. It is connected.
The port 111 is a port selectively connected to the output port 83 to which the third brake B3 is connected.

A control port 112 formed at the end of the port of the orifice control valve 105 opposite to the spring that presses the spool 106 is connected to a port 114 of the 3-4 shift valve 72 via an oil passage 113. ing. The port 114 outputs the signal pressure of the third solenoid valve S3 at the third speed or lower and the fourth speed.
This port outputs the signal pressure of the fourth solenoid valve S4 at a speed higher than the 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 a drain port.

In the 2-3 shift valve 71, the port 11 for outputting the D range pressure at the second or lower speed is selected.
6 is connected to an oil passage 11 through a port 117 which is opened at a place where the spring 92 is disposed in the 2-3 timing valve 89.
8 are connected. 3-4 shift valve 72
The port 119 communicated with the oil passage 87 at the third or lower speed is connected to the solenoid relay valve 100 via the oil passage 120.

In FIG. 4, reference numeral 121 denotes an accumulator for the second brake B2, and reference numeral 122 denotes C
Reference numeral 123 denotes an accumulator for the clutch C0. C-0
The exhaust valve 122 is provided with the clutch C to apply the engine brake only in the second speed in the second speed range.
0 is engaged.

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 pressure regulation level is controlled by a linear solenoid valve. SLU
Can be changed by If the spool 106 of the orifice control valve 105 is located at the position shown in the left half of the figure, the second brake B2 is connected to the oil passage 103 through the orifice control valve 105. Relieving pressure is possible, so that the drain speed from the second brake B2 can be controlled.

In the automatic transmission A described above, the third brake B3 to be engaged to set the second speed is directly controlled by the linear solenoid valve SLU and the B-3 control valve 78. However, the downshift to the second speed, in which the third brake B3 is engaged, is performed when the throttle opening is increased or the vehicle speed is reduced, for example, by changing the driving range from the drive range to the "2" range. It also occurs when switching to the range.

Since such a so-called manual downshift occurs based on manual operation of the shift lever, the drive state of the automatic transmission A is changed to the power-on state, the power-off state, or an intermediate state between them. Either can occur. Therefore, the above-described control device performs the engagement control of the third brake B3 for setting the second speed as follows.

FIG. 5 shows an example of the control routine. First, it is determined whether or not the determination of the downshift to the second speed is established (step 1). This can be determined, for example, by selecting the “2” range when the vehicle speed is equal to or less than the predetermined value, or changing the running state from the third speed state to the second speed state while driving in the “2” range. Can be determined by If a negative determination is made in step 1, the process returns without performing any particular control. If an affirmative determination is made, the drive state of the automatic transmission A is determined.

That is, it is first determined whether or not the throttle opening θ is larger than the first reference value θ1 (step 2). This first reference value θ1 is a value that defines the lower limit of the power-on region set according to the vehicle speed, and is schematically shown in FIG. Therefore step 2
If the answer is affirmative, the automatic transmission A is in the power-on (drive) state, and the input rotational speed (the rotational speed of the clutch C0 or the turbine rotational speed) NC0 is about to increase. The control in the power-on state is executed as a downshift to the second speed (step 3).

The downshift to the second speed is based on the input rotational speed N
This is achieved by increasing C0 to the synchronous speed of the second speed. However, since the input rotational speed NC0 is about to be increased by the torque from the engine E, a gear position higher than the second speed is set. By decreasing the torque capacity of the friction engagement device, the input rotation speed NC0 increases. Therefore, the third brake B3 for setting the second speed is maintained in the released state (low pressure state) immediately after the shift output, and the prediction at the time when the input rotational speed BC0 reaches the synchronous speed of the second speed is established. Then, control for increasing the engagement pressure (torque capacity) is started.

The control of the engagement pressure (torque capacity) of the third brake B3 is controlled by the output pressure (signal pressure) of the above-described linear solenoid valve SLU to increase the duty ratio of the linear solenoid valve SLU. As a result, the signal pressure increases, and the engagement pressure of the third brake B3 increases. A change in the duty ratio of the linear solenoid valve SLU when the third brake B3 is controlled in the power-on state is schematically shown as a solid line in FIG.

That is, at time t0, the downshift to the second speed is performed, and at the same time, the duty ratio is temporarily increased to start supplying the hydraulic pressure to the third brake B3, and the synchronization prediction is established. Until the time t1, the third brake B3 is maintained at a low pressure in a substantially released state by maintaining the duty ratio at a small value. And the predicted synchronization time t
Second, the duty ratio is increased so that the third brake B3 is almost completely engaged.

On the other hand, if the determination in step 2 is negative, it is determined whether or not the throttle opening θ is equal to or less than the second reference value θ2 (step 4). This second reference value θ2
Is a value that defines the upper limit of the power-off region set according to the vehicle speed. As shown in FIG. 6, the first reference value θ1 is set to a lower opening side than the first reference value θ1. Can be represented as a curve drawn substantially parallel to the line. Therefore, if an affirmative determination is made in step 4, the automatic transmission A is in the power-off (non-drive) state, and the input speed NC0 is about to decrease. In this case, the downshift to the second speed is performed. Control in a power-off state is executed as control (step 5).

As described above, the downshift to the second speed is achieved by increasing the input rotational speed NC0 to the synchronous speed of the second speed. However, in the power-off state, the vehicle is running. Input speed N by inertia torque
C0 needs to be raised. Accordingly, in this case, the torque capacity of the third brake B3 for setting the second speed, which is the shift speed after the shift, is increased to bring the automatic transmission A into the second speed state early, and the second speed of the input rotation speed NC0 is set. Promotes synchronization to state.

The control of the engagement pressure (torque capacity) of the third brake B3 is performed by the linear solenoid valve SLU.
Is changed by changing the duty ratio as shown by the broken line in FIG. That is, after the shift output to the second speed (at time t0), the torque capacity of the friction engagement device that has set the higher gear is reduced to tie up (engagement with the disengagement friction engagement device). The duty ratio is increased at an early time point t3 within a range in which both of the friction engagement devices on the side have a torque capacity of a predetermined value or more. As a result, the input rotation speed NC0 is increased by the torque from the output shaft side, and after reaching the second speed synchronous rotation, the duty ratio is increased so that the third brake B3 is in a substantially complete engagement state.

On the other hand, if a negative determination is made in step 4, the throttle opening θ is in a so-called intermediate state between the reference values θ1 and θ2. This intermediate state is defined as an area where power on / off cannot be determined based on the throttle opening and the vehicle speed due to individual differences of the automatic transmission A and changes over time in characteristics. Therefore, if a positive determination is made in step 4,
Since the automatic transmission A is in the intermediate state, the shift control corresponding thereto is executed. Steps 2 and 4 correspond to the intermediate state determining means of the present invention.

When the intermediate state as the driving state of the automatic transmission A is determined, first, a control constant is determined (step 6). This control constant is a constant for linearly interpolating the duty ratio of the linear solenoid valve SLU,
Stated qualitatively, it indicates how much the throttle opening θ is located on the power-on side or the power-off side in the intermediate region shown in FIG. Specifically, it can be obtained by the calculation of (θ−θ2) / (θ1−θ2).

After determining the control constants in this way,
The shift control in the intermediate state is executed (step 7). That is, in the power-on state, the third brake B3 is maintained at a low pressure until the synchronization prediction time, and in the power-off state, the engagement pressure of the third brake B3 is controlled to increase at an early time after the shift output. , The engagement pressure of the third brake B3 is set to an intermediate state between the power-on state and the power-off state. Therefore, steps 6 and 7 correspond to the intermediate speed change control executing means of the present invention.

This will be specifically described using the above control constants. The duty ratio correction value Da is set according to the vehicle speed, and the correction value Da is multiplied by the control constant to correct the duty ratio. Quantity D (= Da · (θ−θ2) /
(Θ1-θ2)). Control constant ((θ-θ2) /
(Θ1−θ2)) indicates how much the detected intermediate state is closer to the power-on side from the power-off state. Therefore, the correction amount D is to change the duty ratio of the power-off state to the power-on side. This indicates the value to be corrected.

Therefore, when it is determined that the automatic transmission A is in the intermediate state, the correction amount D is obtained from the duty ratio of the linear solenoid valve SLU in the power-off state.
The linear solenoid valve SLU is controlled at a duty ratio obtained by subtracting the above, and the engagement pressure of the third brake B3 is controlled. In this case, a guard value may be set as the lower limit value of the duty ratio, and control may be performed so that the duty ratio does not become lower.

Therefore, the duty ratio of the linear solenoid valve SLU changes by a value smaller than the duty ratio in the power-off state by the correction amount D, which is indicated by the hatched area in FIG. Can be represented by By controlling the duty ratio in this way and setting the changing tendency of the engagement pressure of the third brake B3 to an intermediate changing tendency between power-on and power-off,
In the intermediate state in which neither the power-on state nor the power-off state can be determined, the third brake B3 for setting the second speed is not maintained in the substantially released state, so that the shift proceeds. It is prevented that the shift is not performed or the shift is delayed. Conversely, since the engagement pressure (torque capacity) of the third brake B3 is not increased early, it is possible to prevent a sudden change in the input rotation speed NC0 from causing a large shift shock.

Further, even if the driving state of the automatic transmission A changes due to a subtle change in the throttle opening during the shift, the engagement pressure of the third brake B3 is released according to the change in the throttle opening. Since the control is performed to the side or the engagement side, it is possible to prevent the shift shock from deteriorating and the shift from being delayed, as in the case described above.

In the above-described embodiment, since the automatic transmission having the gear train shown in FIG. 2 or the hydraulic circuit shown in FIG. 4 is targeted, control for executing a downshift to the second speed, that is, Although the control of the engagement pressure of the third brake B3 has been described as an example, the present invention is not limited to the above-described embodiment, and the gear train other than the above-described gear train or an automatic transmission having a hydraulic circuit is provided. The present invention can be applied to a control device intended for a transmission. Therefore, the same applies to a case where a shift to a speed other than the second speed is controlled and a case where a friction engagement device other than the third brake is controlled. Can be applied.

In the above embodiment, the engagement pressure of the friction engagement device such as the third brake is controlled so as to linearly change. However, the control pattern of the engagement pressure is arbitrarily set as required. Yes, it may increase or decrease transiently. Further, as described in the above embodiment, the control in the so-called intermediate state does not assume that the control value at the time of power off is linearly interpolated, but uses a control value independently set as a parameter such as a vehicle speed or a throttle opening. It may be executed on the basis of.

[0062]

As described above, according to the present invention,
Set an intermediate state where the drive state of the automatic transmission cannot be determined as either a power-on state or a power-off state,
If the intermediate state is determined, control specific to the intermediate state, which is different from the control in the power-on state and the control in the power-off state, is performed. In addition to this, control against the driving state can be prevented, and as a result, it is possible to prevent a shift shock from becoming worse or a shift delay from becoming noticeable without a shift proceeding.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a control system according to an embodiment of the present invention.

FIG. 2 is a diagram mainly showing a gear train of the automatic transmission.

FIG. 3 is a diagram showing an operation table for setting each shift speed.

FIG. 4 is a diagram showing a part of a hydraulic circuit.

FIG. 5 is a flowchart illustrating an example of a control routine for determining a drive state of the automatic transmission and instructing a shift control in an intermediate state.

FIG. 6 is a diagram showing a power-on area, a power-off area, and an intermediate area according to a throttle opening and a vehicle speed.

FIG. 7 is a time chart showing a control pattern of a duty ratio and a change in an input rotation speed according to a driving state of an automatic transmission at the time of downshifting to a second speed.

[Explanation of symbols]

 A automatic transmission B3 third brake SLU linear solenoid valve 19 electronic control unit for automatic transmission 78 B-3 control valve

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16H 61/00-61/24

Claims (2)

(57) [Claims] 1. A shift control of an automatic transmission in which a shift control from a first shift speed to a second shift speed is made different between a driving state in which the automatic transmission is driven and a non-driving state in which the automatic transmission is not driven. In the device, an intermediate state determining unit that determines an intermediate state between a driving state and a non-driving state of the automatic transmission; and, when the intermediate state is determined by the intermediate state determining unit, a shift control in the driving state; A shift control device for an automatic transmission, comprising: an intermediate shift control execution unit that executes still another shift control different from the shift control in a non-drive state. 2. The method according to claim 1, wherein the intermediate shift control execution unit is configured to control the first
The change tendency of the engagement pressure of the predetermined frictional engagement device involved in the shift from the first gear to the second gear is a change tendency intermediate between the change tendency in the drive state and the change tendency in the non-drive state. 2. The shift control device for an automatic transmission according to claim 1, further comprising a control unit.