JPH0996357A - Control device for automatic transmission - Google Patents

Abstract

(57) [Summary] (Correction) [PROBLEMS] To prevent the engine rotation from rising due to insufficient engagement hydraulic pressure due to an increase in engine torque during gear shifting. SOLUTION: In a region where the engine torque is small, a target value of engagement hydraulic pressure is a first target value LA corresponding to a first characteristic line X1 for a road state and a second characteristic for a no-road state. The second target value LN corresponding to the line X2 is stored.
The first target value LA is set so as to gradually increase as the torque increases, and the second target value LN is set as a fixed value that does not depend on the torque. When the load state is changed to the no load state, the target value is gradually decreased according to the characteristic line X1 as shown by the broken line arrow, and then the target value is changed to the second characteristic line X2 at once. To be selected. When shifting from the no-load state to the load state, the target value shifts from the characteristic line X2 to the first characteristic line X1 via the extension line Y1 as shown by the solid arrow. To do.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission, which prevents the engine from being blown up during a gear shift.

[0002]

2. Description of the Related Art An automatic transmission, particularly an automatic transmission for automobiles, has a multi-stage transmission gear mechanism including, for example, a planetary gear mechanism to switch operating states of a plurality of friction engagement elements such as a brake and a clutch. By changing the combination of engagement and disengagement, the power transmission path of the multi-stage speed change gear mechanism is switched to perform speed change (see, for example, Japanese Patent Publication No. 63-18053).

The friction engagement element is usually hydraulically actuated, and its engagement force is changed by changing the engagement oil pressure. The fastening force needs to be greater than or equal to a predetermined value, but unnecessarily increasing the fastening force is not preferable from the viewpoint of reducing fuel consumption and preventing shift shock. Therefore, the fastening force, that is, the fastening hydraulic pressure is set according to the engine generated torque.

By the way, in a region where the engine generated torque is small, as the throttle opening becomes smaller, that is, as the engine generated torque becomes smaller, from the load state in which the automatic transmission is driven from the engine side to the automatic transmission side. This is the region where the engine is driven to the no-load state. At the switching point between the load state and the no-load state, the engagement hydraulic pressure may be substantially zero, and in the load state where the engine generated torque is larger than this switching point,
It is preferable to set the engaging hydraulic pressure to increase in accordance with the increase in the generated torque. Further, in the no-load state, it is preferable to set the engaging hydraulic pressure to gradually increase from the switching point toward the proper engaging hydraulic pressure when the throttle is fully closed in accordance with the decrease in the generated torque. .

[0005]

As described above, in the region where the engine generated torque is small, including the load condition and the no load condition, during the gear shifting, especially during the shift-up gear shifting, the no-lo When the accelerator is stepped on from the
There may be a transition to the idle state. At this time, due to the response delay of the hydraulic pressure, a quick increase of the engaging hydraulic pressure cannot be obtained according to the increase of the torque generated by the engine, the engaging force of the friction engaging element is insufficient, and the engine temporarily blows up. It will be.

In order to prevent the engine from being blown up during the above-described gear shift, it is conceivable to set a large engagement hydraulic pressure in order to cope with an increase in the torque generated during the gear shift in a region where the engine generated torque is small. However, in this case, the engagement hydraulic pressure in the region where the engine generated torque is small is always larger than the proper value, which is not preferable from the viewpoint of reducing fuel consumption.

The present invention has been made in consideration of the above circumstances, and an object thereof is to prevent the engine from rising during a gear shift while reducing fuel consumption in a region where the engine generated torque is small. Another object of the present invention is to provide a control device for the automatic transmission.

[0008]

In order to achieve the above object, the present invention has the following as a first structure thereof. That is, in an automatic transmission that shifts gears by switching the operating state of the frictional engagement elements to switch the power transmission path, the torque detection means for detecting the torque generated by the engine and the engagement force of the frictional engagement elements. A target value setting means for setting a target value, and a fastening force changing means for changing the fastening force of the frictional fastening element so as to reach the target value,
The target value setting means receives the output from the generated torque detection means, and in a region where the engine generated torque is less than or equal to a predetermined value, the first target having a proper value or more determined from the engine generated torque when the engine generated torque decreases. A value is set, and when the engine generated torque increases, a second target value larger than the first target value is set. Preferred modes based on the above configuration are as described in claims 2, 3, 8, and 9 in the claims.

In order to achieve the above object, the present invention has the following second construction. That is, in an automatic transmission that shifts gears by switching the operating state of the frictional engagement elements to switch the power transmission path, the torque detection means for detecting the torque generated by the engine and the engagement force of the frictional engagement elements. A target value setting means for setting a target value; and a fastening force changing means for changing the fastening force of the frictional fastening element so as to reach the target value. Receiving the output of the engine, the engine driving the engine from the automatic transmission side.
A fixed target value that is equal to or higher than the proper value when the throttle is fully closed is set in the drive state, and a variable set based on the engine generated torque in the load state in which the automatic transmission is driven from the engine side. The target value is set, and the engine generated torque is increased to change from the no-load state to the load state.
It is configured such that the fixed target value is set when shifting to the drive state. Preferred modes based on the above configuration are as described in claims 5, 6, 8, and 9 in the claims.

In order to achieve the above object, the present invention has the following third construction. That is, in an automatic transmission that shifts gears by switching the operating state of the frictional engagement elements to switch the power transmission path, the torque detection means for detecting the torque generated by the engine and the engagement force of the frictional engagement elements. As the target value, a fixed fixed target value that is equal to or more than the appropriate value when the throttle is fully closed is stored in the no-load state, and in the load state, it is changed according to the increase of the engine generated torque. Storage means for storing the variable target value to be increased and stored so that the variable target value in the load state close to the no load state is smaller than the fixed target value. , The fixed target value is selected in the no load state, the variable target value is selected in the load state, and the variable target value is loaded from the no load state.
And a selecting means for selecting a larger target value of the fixed target value and the variable target value in the load state when the state is changed to the drive state. A preferable mode based on the above configuration is as described in claims 8 and 9 in the claims.

[0011]

According to the first aspect of the present invention, when the engine generated torque is apt to be insufficient in the fastening force, the fastening force is set to the second target value which is larger than the first target value which is set to the proper value or more. Therefore, the response delay of the increase in the fastening force is eliminated or reduced, and it is possible to prevent the engine from rising due to the insufficient fastening force. Further, when the engine generated torque is reduced, the fastening force is set according to the small first target value, which is preferable in satisfying the reduction of fuel consumption.

According to the second aspect of the present invention, the second target value is set to a fixed value, and the load on the control system is reduced, including the simplification of the control, and the engine is blown during shifting. This is preferable for surely preventing the rising.

According to the third aspect of the present invention, the first target value is set according to the engine-generated torque that has been conventionally used, and the first target value is optimally set. It will be preferable.

According to the invention described in claim 4, it is possible to obtain the same effect as the effect corresponding to claim 1.
In addition to this, as compared with the case of claim 1, the process of making it possible to set the fixed target value and the variable target value in duplicate at the same engine generated torque becomes unnecessary.

According to the fifth or sixth aspect of the invention, the fixed target value can be smoothly changed to the variable target value.

With the structure described in claim 7, it is possible to obtain the same effect as the effect corresponding to claim 4.

By adopting the structure as described in claim 8, the control is limited to the upshift in which engine uprising during gear shifting is a problem, and is unnecessary in an operating state in which uprising prevention is not a problem. It is preferable in terms of reducing fuel consumption by preventing an increase in fastening force.

With the structure as described in claim 9, it is possible to prevent the engine from being blown up during the gear shift in the case of the hydraulic system in which the response delay of the increase in the fastening force is a particular problem.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, EG is an engine whose engine load is adjusted by adjusting the throttle opening, and the torque generated by this engine EG is transmitted to the drive wheels via the automatic transmission AT.

The automatic transmission AT is composed of a torque converter 2 and a planetary gear type multi-stage transmission gear mechanism 10. The automatic transmission AT will be described below with reference to FIG. First, the torque converter 2 and the multi-stage speed change gear device 10 are sequentially arranged from the engine side coaxially with the crankshaft 1 of the engine EG. The torque converter 2 is
It is equipped with a pump 3, a turbine 4 and a stator 5,
The pump 3 is fixed to the crankshaft 1. The stator 5 rotates via a one-way clutch 6 on a fixed shaft 7 that is integral with the casing C of the multi-stage transmission gear device 10. The one-way clutch 6 allows the stator 5 to rotate in the same direction as the pump 3 but does not allow reverse rotation.

The multi-stage transmission gear device 10 has a base end fixed to the crankshaft 1 and a tip extending through the center of the multi-stage transmission gear device, and drives an oil pump P arranged on a side wall of the device. Therefore, the central shaft 12 connected to the pump
It has. The base end of the central shaft 12 is connected to the turbine 4 of the torque converter 2 and the end thereof extends to the side wall of the multistage speed change gear device 10 and is rotatably supported by the side wall. A hollow turbine shaft 13 is provided. A Ravigneaux type planetary gear unit 14 is provided on the turbine shaft 13. The planetary gear unit 14 includes a small-diameter sun gear 15 and a large-diameter sun gear 15 arranged on the side of the small-diameter sun gear 15 on the side far from the engine. 16, long pinion gear 17, short pinion gear 18, and ring gear 19
Consists of

Forward and coast clutches 20 and 21 are arranged side by side on the side of the planetary gear unit 14 remote from the engine. The forward clutch 20 is a clutch for traveling forward and interrupts power transmission between the small-diameter sun gear 15 and the turbine shaft 13 via a first one-way clutch 22. The coast clutch 21 is connected to the small-diameter sun gear 15 in parallel with the forward clutch 20.
The power transmission between the bin shafts 13 is interrupted. 2 radially outward of the cost clutch 21
-4 brake 23 is disposed. This 2-4 blur
The key 23 is a band brake, and is the large-diameter sun gear 1 described above.
6 has a brake drum 23-1 connected thereto and a brake band 23-2 hung on the brake drum.
Radially outward of the forward clutch 20;
A reverse scratch 24 is arranged on the side of the 2-4 brake 23. This reverse scratch 24
Is a clutch for traveling in reverse, which connects and disconnects the power transmission between the large-diameter sun gear 16 and the turbine shaft 13 via the brake drum 23-1 of the 2-4 brake 23. is there.

A roll-reverse brake 25 for disengaging the carrier 14a of the planetary gear unit 14 and the casing C of the multi-stage transmission gear device 10 is arranged outside the planetary gear unit 14 in the radial direction. ing. Brakes 23 and 25 between above 2-4 and low reverse
A second one-way clutch 26 for disengaging the carrier 14a and the case 10a in parallel with the low reverse brake 25 is disposed therebetween. On the side of the planetary gear unit 14 on the engine side, there is disposed a 3-4 clutch 27 that connects and disconnects power transmission between the carrier 14a of the planetary gear unit and the turbine shaft 13. An output gear 28 connected to the ring gear 19 is disposed on the side of the 3-4 clutch 27 on the engine side, and the gear 28 is attached to the output shaft 28a. Reference numeral 29 in the figure denotes a lock-up clutch for directly connecting the turbine shaft 13 and the crankshaft 1 without passing through the torque converter 2.

The multi-speed transmission gear device 10 having the structure described above.
Has four forward speeds and one reverse speed by itself, and is operated by appropriately operating the clutches 20, 21, 24 and 27 as frictional engagement elements and the brakes 23 and 25. The shift speed can be obtained. In the above configuration, the operational relationship between each shift stage, the clutch, and the brake is shown in FIG. Of the clutches and brakes, only the 2-4 brake 23 (actuator) has two oil chambers on the apply side and the release side, as will be described later. Supply hydraulic pressure to the Apply side and release
The 2-4 brake 23 is fastened only when the hydraulic pressure on the hydraulic pressure side is released. In other hydraulic pressure supply modes, the 2-4 brake 2 is used.
3 is released. The remaining clutches and brakes (each of the actuators) have only one oil chamber, and are engaged when the oil pressure is supplied to this oil chamber.
It is released when the oil pressure in this oil chamber is released.

Referring again to FIG. 1, U is a control unit composed of a microcomputer, which includes a CPU and an R.
Equipped with OM and RAM. The control unit U performs gear shift control, lock-up control, and control of the engaging hydraulic pressure of the brake or clutch as a friction engaging element described later. The control unit U stores, for example, a shift characteristic set with parameters such as throttle opening and vehicle speed, and based on this shift characteristic, a shift-up signal or a shift-down signal is used for shifting the automatic transmission AT. Output to solenoid SL1. In addition, the control unit U
Stores a lock-up characteristic set by using, for example, a throttle opening and a vehicle speed as parameters, and based on the lock-up characteristic, a lock-up signal or a lock-up release signal is sent to lock the automatic transmission AT. Output to the up solenoid SL2. In order to control the engagement hydraulic pressure of the friction engagement element, the control unit U includes the automatic transmission AT.
For example, the line pressure adjusting solenoid SL3 as the fastening force adjusting means is controlled. The lockup clutch 29 is disengaged at the time of shifting.

In the control unit U, for the above control,
The signals from the sensors S1 to S3 are input. Sensor S1
Is for detecting the throttle opening, and constitutes torque generation detecting means of the engine. The sensor S2 detects a vehicle speed and constitutes a vehicle speed detecting means. Sensor S
Reference numeral 3 denotes a turbine torque detecting means, which constitutes a turbine torque detecting means.

Here, with reference to FIG. 4 showing a shift-up state from the first speed to the second speed in a region where the throttle opening is small (for example, a region of several% or less), the engagement hydraulic pressure during shifting is insufficient. The engine will be blown up and the shock will be caused by the excessive tightening oil pressure. In FIG. 4, at time t1, the throttle opening is fully closed, and then the shift up state is set. A shift command signal, that is, a shift-up signal is generated slightly before time t2, and the turbine rotation speed starts to decrease at the time t2 due to the switching of the friction engagement elements (start of inertia phase).

The throttle opening is increased at time t3 during the shifting operation in which the turbine rotation speed is decreasing. At this time, the input torque from the engine EG to the automatic transmission AT increases relatively quickly, but the actual torque of the turbine shaft 13 gradually increases. On the other hand, the engaging hydraulic pressure, that is, the engaging hydraulic pressure to the 2-4 brake 23 that is engaged to shift to the second speed, starts to increase at time t4, which is considerably delayed from time T3. Since the rise of this engagement hydraulic pressure is delayed, 2-4
The fastening force of the brake 23 is insufficient, and the turbine shaft 13, that is, the rotation of the engine EG is swept up. In order to prevent this blowing up, as will be described later, the engagement hydraulic pressure is increased and corrected so as to be temporarily large (set to a value larger than an appropriate value).

After the time point t4 when the engine EG is blown up, the engagement hydraulic pressure is sufficiently high, but the actual torque of the turbine shaft 13 is not sufficiently increased.
For this reason, after the above-mentioned blow-up, the engagement hydraulic pressure becomes excessively large, and as a result, a shock occurs in which the turbine rotation speed sharply decreases. Therefore, in the present embodiment, in order to prevent a shock due to the rapid decrease in the turbine rotation speed, a delay correction is performed to make the increase degree (increase rate) of the engaging hydraulic pressure smaller than the increase degree to make it an appropriate value. I am going to do it.

In FIG. 4, among the changes in the engaging hydraulic pressure, the alternate long and short dash line shows a preferable example of the change. When the throttle opening is increased during the gear shift, the engaging hydraulic pressure is increased to prevent the engine from rising. After that, the degree of increase in the engaging hydraulic pressure is reduced to prevent a rapid change in the turbine rotation speed.

FIG. 5 shows an example of setting the engaging hydraulic pressure for preventing the above-mentioned engine blow-up and the rapid decrease of the turbine rotation speed. In the embodiment, the horizontal axis parameter is set.
The throttle opening corresponding to the engine generated torque is adopted as the parameter. In FIG. 5, the engine torque EG is higher on the side where the engine generated torque is greater than the time point α.
Is a load state in which torque is transmitted from the automatic transmission AT side to the automatic transmission AT, and a region where the engine generated torque is smaller than α is in a no load state in which torque is transmitted from the automatic transmission AT side to the engine EG. .

In the load state, the first target value LA set according to the engine generated torque is set and stored as the characteristic line X1. More specifically, the first target value LA
Is set to zero at α, which is the boundary between the load state and the load state, and is set to increase non-linearly (hyperbolic curve) as the engine generated torque increases.
Such a first target value LA is set to a value equal to or larger than an appropriate value determined by the engine generated torque, but is set to be the appropriate value itself in the embodiment.

In the no-load state, the second target value LN is
As indicated by the characteristic line X2, it is set as a fixed value that does not change depending on the engine generated torque. That is, when the throttle opening is fully closed, that is, when the engine load is zero, the engagement hydraulic pressure is required to be a predetermined proper value that is considerably larger than zero, but the second target value LN is
The value is set to be equal to or slightly larger than the appropriate value when the throttle is fully closed. In the embodiment, the second target value LN is set according to the vehicle speed indicating the inertia of the drive system (the higher the vehicle speed, the larger the second target value LN). The first target value LA and the second target value LN as described above
(X1 and X2) are respectively stored in the ROM of the control unit U as a storage means.

In FIG. 5, further characteristic lines Y1 and Y2 are assumed. The characteristic line Y1 is an extension of the characteristic line X2 until it intersects with the characteristic line X1 (the intersection with X1 is indicated by the symbol β), and the target value based on the characteristic line Y1 is
It is the same as the second target value LN. Further, the characteristic line Y2 is set by using the engine generated torque as a parameter, and is set so that the increasing rate, that is, the increasing rate according to the increase of the engine generating torque, is smaller than that of the characteristic line X1. There is. The characteristic line Y2 starts from the characteristic line X1 at the boundary between the load state and the no-load state, and linearly increases as the torque increases, and the intersection point with the characteristic line X1 increases. It is indicated by the symbol γ.

Selection of the engagement hydraulic pressure is performed as follows.
First, when the engine generated torque is reduced and the load state is shifted to the no load state, it is as shown by the broken line arrow in FIG. That is, the target value decreases according to the characteristic line X1 and becomes zero at the time point α, and the characteristic line X2 shifts at once at the time point α, and then the characteristic line X2 is followed. In other words, when the load state is changed to the no load state, the first set value in the load state is set.
The target value LA and the second target value LN which is the set value in the node state are selected according to the basic setting.

When shifting from the no-load state to the no-load state, the target value of the engaging hydraulic pressure is selected as shown by the solid line in FIG. That is, the characteristic line X up to time α
The second target value LN according to 2 is set, and after the time point α, it follows the characteristic line Y1 and remains the second target value LN, and from the time point β, the first target value LA that follows the characteristic line X1. Will be selected. When the torque still increases after the time point γ, the characteristic line Y2 is followed, and the increase rate of the target value is smaller than the first target value LA according to the characteristic line X1.

As is apparent from the above description, when the transition from the no-load state to the load state is made, the target value of the engaging hydraulic pressure is set to the second target value larger than the first target value LA. L
By setting to N, the above-described increase correction of the engagement hydraulic pressure in FIG. 4 is performed, and engine upswing is prevented or reduced. Further, by decreasing the rate of increase of the engaging hydraulic pressure according to the characteristic line Y2, the delay of the engaging hydraulic pressure of FIG. 4 described above is corrected, and the turbine rotation speed rapidly decreases (shock resulting from the shock). Is prevented. It should be noted that both the first target value and the second target value are gear types (1
The speed is set according to the shift from the second speed to the second speed, the shift from the second speed to the third speed, and the like. Therefore, the content shown in FIG. 5 is set for each type of shift.

Here, the most preferable value (appropriate value) of the target value of the engaging hydraulic pressure set in accordance with the engine generated torque in the no load state from the reduction of fuel consumption is 2 in FIG.
It follows the characteristic line Y2 indicated by the dashed line. That is, the ideal mode is one in which the target value of the engagement hydraulic pressure is gradually increased from the time point α in accordance with the decrease in torque, and changes to the appropriate value when the throttle is fully closed. Therefore, the setting of the second target value LN corresponding to the characteristic line X2 is made larger than that corresponding to the characteristic line Y3, which is disadvantageous in reducing fuel consumption by this amount, but prevents the engine from rising during shifting. In order to perform effectively, it is preferable to set the engagement hydraulic pressure to be equal to or higher than the proper engagement hydraulic pressure when the throttle is fully closed.

Details for performing the above-mentioned control by the control unit U are shown in the flowchart of FIG. The flow chart of FIG. 6 will be described below. In the following description, Q indicates a step.

First, in Q1, the throttle opening TV
O, vehicle speed VSP, and turbine torque TNT are read. Next, in Q2, the shift determination is performed. At this time, the determination of the type of shift and the determination of the load state (where the engine generated torque is located in FIG. 5) are performed.

At Q3, it is judged if the upshift is being performed. This determination is made, for example, based on whether or not the turbine phase is being changed during the inner phase, or when there is no predetermined shift end signal after the predetermined shift command signal is output. Depending on the status (corresponding to the setting of the shift flag). If the determination in Q3 is NO, it means that the control of the engagement hydraulic pressure according to the present invention is unnecessary, and the flag is reset to 0 in Q4 and Q1 is set.
Return to. The flag is set to 1 when the node is in the node state.

When the determination in Q3 is YES, it is determined in Q4 whether or not the current load state is present. This Q
When it is NO in the judgment of 4, it means that it is in the no load state,
At this time, the flag is set to 1 in Q6, and then LM described later is cleared to 0 in Q7 (LM
Is for setting the characteristic line Y2 in FIG. 5), and in Q8,
The target value PL of the engagement hydraulic pressure is set as the second target value LN corresponding to the characteristic line X2 in FIG.

When the determination in Q5 is YES, the first target value LA is temporarily set in Q9. Next, at Q10, it is judged if the flag is 1. This Q
When the result of the determination in 10 is NO, it means that the transition from the no-load state to the load state has not been made. At this time, Q11
In, the first target value LA temporarily set in Q9 is set as it is as the final target value PL.

If the result of the determination in Q10 is YES, it means no
This is the time when the load state is changed to the load state. At this time, in Q12, the second target value LN is provisionally set. Next, at Q13, a predetermined increase amount of the engagement hydraulic pressure is added to the previous value of LM to set the current value LM. Q
The increase rate of the engagement hydraulic pressure in 13 corresponds to the characteristic line Y2, and is smaller than the increase rate of the first target value LA according to the characteristic line X1.

After Q13, in Q14, LN and LM
And are added to set a temporary target value PL1. This PL1 is a target value corresponding to the characteristic line Y2 in FIG.
Next, in Q15, the first target value LA and the second target value L
The larger target value is selected from N and the provisional target value PL2 is determined. This provisional target value PL2 corresponds to the transition to X1 via the characteristic line Y1. Further, in Q16, the smaller one of the provisional target values PL1 and PL2 is selected, and the final target value PL is determined.

After the above Q8, Q11, or 116, the routine proceeds to Q17, where the determined target value PL
Is output (the solenoid SL3 for adjusting the engagement hydraulic pressure is controlled so as to reach the target value PL).

In the above embodiment, FIG. 5 constitutes the target value setting means or the storage means. Further, in FIG. 6, Q8, Q9, Q11 and Q12 form a target value setting means, and Q15 forms a target value selecting means. In addition,
Each step in FIG. 6 constitutes means for realizing a predetermined function, and can be expressed as a functional member by adding the letters of the means to the name representative of the function.

Although the embodiment has been described above, the present invention is not limited to this, and includes, for example, the following cases.

In the load state, the values corresponding to the characteristic lines X2 and Y1 shown in FIG. 5 are set and stored as the second target values used when the no-load state is changed to the load state. Then, the stored second target value may be compared with the first target value obtained based on the characteristic line X1, and the larger value may be selected as the final target value. .

Similar control can be performed during downshifting. Further, the multi-stage transmission gear mechanism that constitutes the automatic transmission AT is not limited to the planetary gear type, but may be of an appropriate type. Furthermore, the frictional fastening elements may be electromagnetic rather than hydraulic (in which case the fastening force is adjusted, for example by adjusting the supply power).

The engine generated torque as a parameter for setting (memorizing) the target value in FIG. 5 is not only a parameter shown as an engine load such as a throttle opening but also an appropriate parameter related to the engine generated torque. Can be used. Further, the engine generated torque may be theoretically determined from the intake air amount of the engine and the engine speed. Therefore, in 9, it is possible to use, for example, the throttle opening instead of the turbine torque.

When the turbine torque is determined, the engine generated torque is determined by comparing the ignition timing determined from the engine speed and the intake air amount with a table in which the ignition timing and the engine generated torque are associated with each other. However, the turbine torque may be determined from the determined engine generated torque, the engine speed, and the turbine speed.

The object of the present invention is not limited to the specified one, and implicitly includes the object corresponding to the effect of the invention or the advantage, and the object corresponding to the preferable contents. Of course, the present invention can be expressed not only as an apparatus but also as a method.

[Brief description of drawings]

FIG. 1 is an overall system diagram showing one embodiment of the present invention.

FIG. 2 is a skeleton diagram showing an example of an automatic transmission.

FIG. 3 is a diagram showing a relationship between a shift speed of the automatic transmission shown in FIG. 2 and an operating state of a friction engagement element.

FIG. 4 is a time chart schematically showing the control contents of the present invention.
G.

FIG. 5 is a diagram showing an example of setting a target fastening force.

FIG. 6 is a flowchart showing a control example of the present invention.

[Explanation of symbols]

EG: engine AT: automatic transmission SL1: shift solenoid SL3: engagement hydraulic adjustment solenoid S1: throttle opening sensor S2: vehicle speed sensor LA: first target value LN: second target value U: control unit X1: characteristic line (For setting the first target value) X2: Characteristic line (for setting the second target value) Y1: Characteristic line (for correcting the response delay of increasing the fastening force, the second
Use target value) Y2: Characteristic line (for correction to decrease the increase rate of fastening force)

Claims (9)

[Claims] 1. An automatic transmission in which an operation state of a frictional engagement element is switched to switch a power transmission path to perform a gear shift, a torque detecting means for detecting a torque generated by an engine, and the frictional engagement element. A target value setting means for setting a target value of the fastening force, and a fastening force changing means for changing the fastening force of the frictional fastening element so as to have the target value, the target value setting means, the generated torque In response to the output from the detecting means, in a region where the engine generated torque is equal to or lower than a predetermined value, a first target value which is equal to or higher than an appropriate value determined by the engine generated torque is set when the engine generated torque decreases, and the first target value is set when the engine generated torque increases. Second larger than the target value
A control device for an automatic transmission, characterized in that a target value is set. 2. The control device for an automatic transmission according to claim 1, wherein the second target value is set as a fixed target value that is equal to or higher than an appropriate value when the throttle is fully closed. 3. The control device for an automatic transmission according to claim 1, wherein the first target value is set so as to increase as the engine generated torque increases. 4. An automatic transmission in which an operating state of a friction engagement element is switched to switch a power transmission system path to perform a gear shift, a torque detecting means for detecting a torque generated by an engine, and the friction engagement element. A target value setting means for setting a target value of the fastening force, and a fastening force changing means for changing the fastening force of the frictional fastening element so as to have the target value, the target value setting means, the generated torque In response to the output from the detection means, when the engine is being driven from the automatic transmission side, a fixed fixed target value which is equal to or higher than an appropriate value when the throttle is fully closed is set, and the engine side is set. In the load state for driving the automatic transmission from, set the variable target value that is set based on the engine generated torque,
In addition, the fixed target value is set when the no-load state is changed to the load state due to an increase in the torque generated by the engine. 5. The predetermined value until the variable target value becomes larger than the fixed target value when the target value setting means shifts from the no-load state to the load state. A control device for an automatic transmission, wherein the fixed target value is set only for a time. 6. The target value setting means according to claim 4, wherein the target value setting means sets a larger target value among the fixed target value and the variable target value when the load condition changes from the no-load condition to the load condition. An automatic transmission control device characterized by setting a value. 7. An automatic transmission in which an operation state of a frictional engagement element is switched to switch a power transmission system path to perform a gear shift, a torque detection means for detecting a torque generated by an engine, and the frictional engagement element. As the target value of the engaging force, a fixed fixed target value that is equal to or higher than the appropriate value when the throttle is fully closed is stored in the no-load state, and the engine generated torque is increased in the load state. The variable target value which is increased in accordance with the above is stored, and further, the variable target value in the load state close to the no load state is stored so as to be smaller than the fixed target value. The storage means and the fixed target value are selected when the node is in the load state, and the fixed target value is selected.
The variable target value is selected in the load state, and the fixed target value or the variable target value whichever is larger in the load state when the load state is changed from the no load state to the load state And a selecting means for selecting a target value of the automatic transmission. 8. The automatic transmission according to claim 1, wherein the target value is set and selected on the condition that a shift-up shift is being performed. Control device. 9. The friction engagement element according to claim 1, wherein the friction engagement element is a hydraulic type, and the engagement force changing means changes an engagement oil pressure supplied to the friction engagement element. A control device for an automatic transmission characterized by being set to.