JP2857941B2 - 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 an automatic transmission.

[0002]

2. Description of the Related Art A multi-plate type frictional engagement device having a plurality of friction plates is widely used for a clutch or a brake which is engaged to set each gear in an automatic transmission for a vehicle. . In this type of friction engagement device, the larger the radius, the larger the number of friction plates, and the larger the contact pressure of the friction plates, the larger the transmission torque capacity. However, since the automatic transmission needs to be as small and light as possible, various attempts have conventionally been made to reduce the size of the friction engagement device as much as possible. For example, in the invention filed in Japanese Patent Application No. 1-265463, the torque applied to an input member such as an input shaft in a gear transmission mechanism is reduced when setting the reverse gear at which the gear ratio becomes the largest.

[0003]

Means for reducing the torque input to the gear transmission mechanism include means for changing the ignition timing retard amount of the engine, means for reducing the fuel injection amount, and a torque converter stator. Means for controlling and reducing the torque amplification factor are known. However, in the case where the torque is reduced in the reverse gear as in the above-described invention, a frictional engagement device having a capacity corresponding to the reduced input torque is used as the frictional engagement device engaged for setting the reverse gear. Therefore, when the torque reduction control cannot be performed, excessive friction is applied to the friction engagement device, causing slippage, and causing a problem of reduced durability.

The present invention has been made in view of the above circumstances, and aims to improve the durability of a predetermined frictional engagement device by preventing an excessive torque from being applied even when torque reduction control cannot be performed. It is an object of the present invention to provide a control device capable of performing the following.

[0005]

According to the first aspect of the present invention, in order to achieve the above object, the following means are provided as main means. That is, as shown in principle in FIG. 1, the control device 1 of the present invention includes a plurality of frictional engagement devices 2 and a plurality of frictional engagement devices 2 including a reverse gear by selectively engaging the frictional engagement devices 2. The automatic transmission 3 is set to the first gear and includes a torque reducing means 4. The torque reducing means 4 is for reducing the torque applied to the frictional engagement device 2 to be engaged for setting the reverse speed. When setting the reverse speed, the sub-throttle valve ( The gear train in the automatic transmission 3 is closed, for example, by closing the ignition timing, changing the amount of advance of the ignition timing, or reducing the fuel injection amount, and further decreasing the torque amplification rate in a torque converter (not shown). This is to reduce the input torque. Alternatively, another gear train preceding the gear train for setting the reverse gear is shifted to the higher gear. Further, the control device 1 includes a torque reduction impossible detecting means 6 for detecting that the torque reducing means 4 cannot reduce the torque, and a reverse gear inhibiting means 7. The reverse gear prohibiting means 7 controls to prohibit the setting of the reverse gear when the torque cannot be reduced. For example, when the vehicle speed is equal to or higher than a predetermined vehicle speed or when a brake signal is input. For example, when there is no reverse gear, a means for outputting a signal to a valve for maintaining a frictional engagement device engaged for setting a reverse gear in a released state, a means for inhibiting selection of a reverse range by a shift lever, and the like are provided. According to the invention of claim 2, torque cannot be reduced.
Instead of prohibiting the reverse gear,
Means for increasing the line pressure, which is the source pressure of the hydraulic pressure for engaging
It is characterized by having. Further billing
The invention of Item 3 is the output of the auxiliary transmission portion capable of shifting between high and low speeds.
Main transmission section that can set reverse speed and multiple forward speeds
Automatic transmission with a gear transmission mechanism connected to
Of the friction engagement device for setting each gear position.
When controlling reverse and release and setting the reverse gear,
Input torque reduction to reduce the torque input to the speed mechanism
A control device for an automatic transmission comprising:
Input torque reduction failure that detects a state where torque cannot be reduced
Detectable means and the input torque reduction improper detection means
If it is detected that the torque cannot be reduced,
Sub-transmission control means for setting the speed portion to a high speed stage.
It is characterized by having.

[0006]

In the control device according to the first aspect of the present invention, the input torque of the automatic transmission is reduced based on the output signal from the torque reduction means when the reverse gear is selected, or the reverse gear is normally selected. , The input torque to the gear train is reduced. Friction engagement device 2 engaged to set reverse speed
Has a torque capacity adapted to the reduced torque, so that the friction engagement device 2 does not slip excessively. When torque reduction control by the torque reduction means 4 cannot be performed, the torque reduction impossibility detection means 6 detects this and outputs a signal to the reverse gear prohibition means 7. As a result, the frictional engagement device 2 to be engaged to set the reverse gear is maintained in the released state, or the operation of selecting the reverse gear itself is not performed. 2 does not engage, so that no excessive torque acts on it, so that its durability is good. Further, in the invention of claim 2, the frictional engagement
If the torque applied to the joint device cannot be reduced,
As the hydraulic pressure supplied to the joint device increases, the frictional engagement
The device does not slip and its durability is improved
You. Further, in the invention according to claim 3, when setting the reverse gear,
If the torque input to the gear transmission is not reduced,
High-speed sub-transmission that precedes the main transmission that sets the reverse
As the gear is set, it is used as the main transmission for setting the reverse gear.
Reduced input torque, thus setting reverse
Torque applied to the frictional engagement device for
Durability is improved.

[0007]

FIG. 2 is a block diagram showing an embodiment of the present invention.
, A sub transmission unit 12 and a main transmission unit 13. The auxiliary transmission unit 12 is a transmission unit for overdrive,
Two speeds, a high speed and a low speed, are performed, and the main transmission unit 13 sets a plurality of forward speeds and reverse speeds. These transmission sections 12, 13
Will be described later.

The gears in the transmission sections 12 and 13 are shifted by appropriately engaging or disengaging frictional engagement devices such as clutches and brakes.
4 are provided. The switching between supply and discharge of the hydraulic pressure by the hydraulic control device 14 is performed by first to fourth four solenoid valves 15, 16, 17, and 18. Of these, the first solenoid valve 15 is a sub-shift. The section 12 switches between a high speed stage (high) and a low speed stage (low). Also, the second solenoid valve 1
Reference numeral 6 denotes a shift between the first speed and the second speed in the main transmission portion 13, a third solenoid valve 17 executes a shift between the second speed and the third speed, and a fourth solenoid valve 18 outputs the third speed. Speed and fourth
The shift with the speed is executed. Further, the hydraulic control device 14 includes a reverse control valve described later and a solenoid valve for controlling the reverse control valve.

A control unit (ECU) 19 for controlling each of the above-mentioned solenoid valves includes an arithmetic processing unit 20 and a storage unit 2.
1 and an input / output interface 22, and controls the gears in the transmission units 12, 13 to reduce the input torque and inhibit the reverse gear based on the input signals. That is, the control device 19 includes a shift position signal Sp corresponding to a position selected by the shift lever 23 such as a parking (P) range, a reverse (R) range, a neutral (N) range, or a drive (D) range, and a vehicle speed V. , A signal corresponding to the throttle opening θ, a driving mode signal corresponding to the N (normal) mode or P (power) mode, a signal corresponding to the engine coolant temperature Tw, a signal corresponding to the engine speed Ne, and the like. Signal is input. Then, a gear position to be set is selected according to a vehicle speed V, a throttle opening θ, and a gear shift map (shift diagram) corresponding to the selected traveling mode, and the first to fourth solenoid valves 15 are set so as to achieve the gear position. , To 18 are output. Further, the control device 19 performs control to reduce the input torque to the automatic transmission 10 when setting the reverse gear, and the shift position signal S accompanying the selection of the R range by the shift lever 23 is set.
When p is input, a signal for reducing the opening of the sub-throttle valve 24 is output. Here sub throttle valve 2
Reference numeral 4 denotes an intake valve provided upstream of the main throttle valve in the intake system of the engine, that is, on the side of an air filter (not shown), and by reducing the amount of intake air within a range where the engine speed does not decrease. ,
It is known to reduce engine torque and constitute a traction control system. Further, the control device 19 outputs a signal for prohibiting the reverse gear when the reduction control of the input torque cannot be performed. Specific means for inhibiting the reverse gear will be described later.

FIG. 3 is a skeleton diagram showing a specific example of the automatic transmission 10 described above. Automatic transmission 10 shown here
Is provided with a lock-up clutch 25, and the lock-up clutch 25
Is provided between a front cover 27 integrated with the pump impeller 26 and a member (hub) 29 to which a turbine runner 28 is integrally attached. The engine crankshaft (not shown) is a front cover 2
The input shaft 30 connected to the turbine 7 and the turbine runner 28 is connected to a carrier 32 of an overdrive planetary gear mechanism 31 constituting the subtransmission unit 12. A multi-plate clutch C0 and a one-way clutch F0 are provided between the carrier 32 and the sun gear 33 in the planetary gear mechanism 31. The one-way clutch F0 is engaged when the sun gear 33 rotates forward relative to the carrier 32 (rotation in the rotation direction of the input shaft 30). A multi-disc brake B0 for selectively stopping the rotation of the sun gear 33 is provided. A ring gear 34, which is an output element of the auxiliary transmission section 12, is connected to an intermediate shaft 35, which is an input element of the main transmission section 13. Accordingly, when the multi-plate clutch C0 or the one-way clutch F0 is engaged, the subtransmission portion 12 rotates as a whole with the planetary gear mechanism 31 integrally.
Rotate at the same speed as the input shaft 30, and when the brake B0 is engaged to stop the rotation of the sun gear 33, the ring gear 34 is increased in speed with respect to the input shaft 30 to rotate forward. .

On the other hand, the main transmission section 13 has 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 to each other. The third planetary gear mechanism 60 and the carrier 62 are connected to each other, and the output shaft 70 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 13, 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 35, 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 second clutch C2 and the second clutch C2. Next, regarding the brake, the first brake B1 is a band brake,
The first planetary gear mechanism 40 and the second planetary gear mechanism 50 are arranged to stop the rotation of the sun gears 41 and 51. The sun gears 41 and 51 and the casing 71
A first one-way clutch F1 and a second brake B2, which is a multi-disc brake, are arranged in series between the first one-way clutch F1 and the first one-way clutch F1 in which the sun gears 41 and 51 rotate in reverse (the input shaft 35). (Rotation in the direction opposite to the rotation direction of the rotation direction). The third brake B3, which is a multi-plate brake, is provided between the carrier 42 of the first planetary gear mechanism 40 and the casing 71. 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 between the casing 71. The second one-way clutch F
2 engages when the ring gear 63 attempts to rotate in the reverse direction.

In the automatic transmission 10 described above, the auxiliary transmission section 12 can perform high-low two-stage switching, and the main transmission section 13 can perform four-stage shifting on the forward side. FIG. 4 shows an engagement operation table of each clutch and brake for setting these shift speeds. In FIG. 4, a circle indicates an engaged state, a black circle indicates an engaged state during engine braking, and a blank indicates a released state.

As can be seen from FIG. 4, the reverse gear is set by engaging the fourth brake B4, and in this embodiment, the means for inhibiting the reverse gear is the fourth gear.
It is configured to maintain the brake B4 in the released state. FIG. 5 is a hydraulic circuit diagram showing one example thereof, which is mainly composed of a reverse control valve 90 interposed in an oil passage from a manual valve 80 to a fourth brake B4 and a reverse prohibiting solenoid valve 100 for controlling the reverse control valve 90. ing. The reverse control valve 90 has a bottomed cylindrical cup member 92 disposed at one end of a spool 91 having two lands, and a spring 93 disposed inside the cup member 92. 5 and the cup member 92 is pressed upward in FIG.
A first port 94, a second port 95, a brake port 96, and a drain port 97 are formed in this order from the top. The upper land of the spool 91 in the drawing has a slightly smaller diameter than the lower land, the first port 94 is always in communication with these lands, and the second port 9
5 communicates with the brake port 96 when the spool 91 is at the upper position in FIG. 5, and is shut off from the brake port 96 when the spool 91 is at the lower position. The drain port 97 is the second port 9
Contrary to 5, when the spool 91 is on the upper side, it is closed by the cup member 92, and when the spool 91 is on the lower side, it communicates with the brake port 96. Further, a control port 98 communicating with the inside of the cup member 92 is formed in the reverse control valve 90, and a line pressure oil passage 99 is connected to the control port 98. A solenoid valve 100 is connected via an orifice 101. A reverse port 81 of a manual valve 80 is connected to the first port 94 and the second port 95, and a line pressure port 82 is selected by selecting an R range.
The line pressure PL is supplied to the first port 94 and the second port 95 by communicating with the reverse port 81. The fourth brake B4 is connected to the brake port 96.

The reverse prohibition solenoid valve 100
Is the drain port 1 when the power is turned off (ie, in the OFF state).
02 is closed to generate a line pressure at the control port 98, and conversely, the drain port 102 is opened to release the pressure during energization (that is, in the ON state), thereby releasing the control port 98
The reverse prohibition solenoid valve 100 is ON / OFF controlled by the control device 19. Therefore, FIG.
In the hydraulic circuit shown in FIG.
In the normal state where 00 is OFF, the spool 91 of the reverse control valve 90 is at the upper position in FIG. 5 and the second port 95 and the brake port 96 communicate with each other. 8
0 is applied to the fourth brake B4 to be engaged, and conversely, when the reverse prohibition solenoid valve 100 is ON, the manual valve 8
Since the spool 91 is pushed down against the spring 93 by the line pressure PL sent through 0, the brake port 96 communicates with the drain port 97 and is discharged from the fourth brake B4 to be released.

Next, the operation of the control device 19 for the above-described automatic transmission will be described with reference to the flowcharts shown in FIGS. 6 and 7 show one flowchart divided into two drawings for convenience of drawing, and the circled lines of the same number are connected to each other.

First, at step 200, the throttle opening θ
, A signal corresponding to the vehicle speed V, the engine speed N
Processing of an input signal such as a signal corresponding to e is performed, and then, in step 201, it is determined whether or not the shift from the N range or the P range to the R range has been performed. If the determination result is "yes", the vehicle speed V and the engine speed N
e, the throttle opening θ and the input torque reduction control are determined. That is, in step 202, it is determined whether or not the detected vehicle speed V is lower than a reference vehicle speed V0 (for example, 5 km / h). If the determination result is "no", the control process returns. Proceed to step 203. Such a determination regarding the vehicle speed V is made because the torque applied to the friction engagement device becomes the largest during a stall, and therefore, if the vehicle speed V is a certain speed or more, it is necessary to take particular measures for protecting the friction engagement device. Because there is no.

In step 203, it is determined whether or not the engine speed Ne exceeds a reference value N0 (for example, 3000 rpm). If the determination result is "no", the control process returns, and if "yes", the control process returns. If there is, the routine proceeds to step 204, where it is determined whether or not the throttle opening θ is equal to or more than a reference value θ0 (for example, 50%). The judgment process of these steps 203 and 204 is to judge whether or not the engine output is large. Such judgment is made when the engine output is excessively large. This is because excessive slip and wear occur in the device. Therefore, if the result of the determination in step 204 is "no", the control process returns.
Then, it is determined whether or not the input torque reduction control cannot be performed.

In the control device 19 shown in FIG. 2, the control for reducing the input torque is executed by reducing the opening degree of the sub-throttle valve 24. However, a command signal for that purpose cannot be output, or the control device 19 shown in FIG. Actuator (not shown) and sub throttle valve 2
4 causes an abnormality in the sub throttle valve 24
If the control device cannot be closed, the control device 19 determines such a situation based on various input signals. That is, if the input torque reduction control can be executed, the result of the determination in step 205 becomes “No” and the control process returns. If the input torque reduction control cannot be executed for some reason, step 205 Is "yes" and the routine proceeds to step 206. Here, the circumstances where the input torque cannot be reduced include the case where the input torque reduction control is prohibited in relation to other controls.

In step 206, an output is displayed on the indicator to indicate that the input torque reduction control is not possible . In step 207, the line pressure PL is increased . This step
Step 207 corresponds to the line pressure increasing means according to the second aspect of the present invention.
You. Transmission torque capacity of ie the friction engagement device is increased and in accordance with the contact pressure of the friction plates are, and since the engagement of the friction engagement device is performed by the line pressure PL, if higher line pressure PL, The transmission torque capacity of the friction engagement device is increased, and slippage is less likely to occur. In step 208 following this, it is determined whether or not the control flag F1 is "0".
This control flag F1 indicates whether or not the elapsed time after the line pressure PL has been increased is counted. Since it is initially reset to zero, the result of the determination at the step 208 for the first time is determined. Becomes “yes”
Proceed to step 209. In step 209, the timer T1 is reset to zero to start counting, and in step 210, the control flag F1 is set to "1".

In step 211, it is determined whether or not the count value of the timer T1 has exceeded a predetermined reference value A. Until the count value exceeds the reference value A, that is, while the determination result is "no", step 211 is performed. Return to before 202. That is, increasing the line pressure PL is one means for preventing the frictional engagement device from slipping. Therefore, after increasing the line pressure PL, the conditions of Steps 202 to 205 are determined again.
If any one of the determination results is “No”, the control process returns. In addition, if all the judgment results from step 202 to step 205 are “yes”,
Indicator output (step 206) and line pressure P
The control for increasing L (step 207) is continued. Then, at step 208 again, since the control flag F1 has already been set to "1", the result of the determination at step 208 is "no", and the routine proceeds to step 211.

After the control of steps 202 to 211 is repeated, if the count value of the timer T1 exceeds the reference value A, the judgment result of step 211 becomes "yes", and the output of the reverse prohibition indicator is made in step 212. And indicates that the reverse gear cannot be set. Next, in step 213, reverse prohibition control is executed. That is, in the automatic transmission 10 provided with the gear transmission mechanism shown in FIG. 3, the fourth brake B4 is engaged to set the reverse speed, and the reverse control valve 90 shown in FIG. In step 213, a signal for turning on the reverse inhibition solenoid valve 100 shown in FIG. 5 is output. As a result, the line pressure PL does not act on the control port 98 of the reverse control valve 90, so that the spool 91 is pushed down by the line pressure PL acting on the first port 94 to the lower side in FIG. Is communicated to the drain port 97, the pressure is released from the fourth brake B4, and the pressure is released.

That is, when the input torque cannot be reduced in setting the reverse gear having the largest gear ratio,
Since the fourth brake B4 to be engaged to set the reverse gear is kept released, excessive torque is not applied to the fourth brake B4, and its excessive slippage, wear and durability are reduced. Is prevented.

The above-described reverse prohibition control is continued while the reverse lever is selected by the shift lever 23.
When another range is selected, the prohibition control is released. That is, the determination result in step 201 is “no”
If so, the routine proceeds to step 214, where the reverse prohibition control is released, and then the control flag F1 is reset to zero (step 215). This reverse prohibition control is released
Specifically, the ON operation of the reverse prohibition solenoid valve 100 based on the shift position signal Sp is stopped,
The solenoid valve 100 is turned off.

Here, the reference value A to be compared with the count value of the timer T1 will be described. As described above, the slippage of the friction engagement device is caused by a small transmission torque capacity with respect to the applied torque. Therefore, as shown in the flowcharts of FIGS. When the slippage of the joint device is to be prevented in advance, the reference value A can be made relatively long. On the other hand, when the line pressure PL is not sufficiently high or when it is impossible to control to increase the line pressure PL, the transmission torque capacity of the friction engagement device becomes small and the friction engagement device slips violently. I do. When the control for increasing the line pressure PL is not performed, the reference value A is minimized. Such a control for changing the reference value A in accordance with the situation is performed, for example, as shown in FIG.
A map for the reference value A as shown in (1) may be prepared in advance, and a value suitable for the situation may be selected from the map and used. In FIG. 8, A1> A2≥A3.

By the way, in the automatic transmission 10 having the gear transmission mechanism shown in FIG. 3, the reverse gear is set substantially by the main transmission unit 13, so that the torque input to the main transmission unit 13 is reduced. For this reason, in the reverse gear, the sub-transmission portion 12 is set to a high gear (high) with a small gear ratio (see FIG. 4). Therefore, in the automatic transmission 10 having the configuration shown in FIG. 3, when the reverse gear is set when both the control for reducing the input torque and the setting of the high gear in the sub-transmission 12 are impossible, the largest torque is applied to the fourth brake B4. It takes. In other words,
In the above-described control device 19, when setting the reverse speed, an excessive torque is applied to the fourth brake B4 by taking protective measures of reducing the input torque and setting the sub-transmission portion 12 to the high speed. I do not take it . Therefore the latter
A protection measure for setting the sub-transmission portion 12 of the vehicle at a high speed stage is described in claim 3.
Corresponds to the auxiliary transmission section control means.

Therefore, in the above-described control device for performing the two torque reduction controls, the reverse prohibition control described above is performed under the condition that any of these controls cannot be performed. Pressure PL
It is also possible to respond by increasing the pressure or increasing the amount of reduction in the input torque. One example is shown in the flowchart of FIG. That is, input signal processing (step 220)
Is performed, it is determined whether or not the input torque reduction control cannot be performed (step 221). If the determination result is "yes", the process proceeds to step 222 to determine whether the upshift of the subtransmission unit 12 can be performed. A determination is made as to whether or not it is. If the result of the determination is "yes", none of these torque reduction controls is possible, and the fourth brake B4
Since an excessive torque is applied to the motor, reverse prohibition control is executed (step 223).

On the other hand, when only one of the controls for reducing the torque is impossible, the reverse prohibition control is not performed, and the control is performed by increasing the line pressure PL. That is, when the input transmission torque reduction control cannot be performed, but the sub-transmission portion 12 can be set to the high speed stage (if the determination result in step 222 is “no”), the line pressure PL is increased (step 224), thereby increasing the friction. The transmission torque capacity of the engagement device is increased to prevent its slip.

If the input torque reduction control is executable ("NO" in step 221) and the upshift of the subtransmission unit 12 cannot be performed ("YES" in step 225), the input torque reduction amount is increased. (Step 226) and increase the line pressure PL (step 227). In this case, since a higher line pressure PL to the after conducting a reduction of the input torque, the boost amount in our Kerura in pressure PL in step 227 may be less than the boosted amount of the line pressure PL at step 224.

In the above-described embodiment, the input torque reduction control is performed by reducing the opening of the sub-throttle valve. However, the present invention is not limited to the above-described embodiment. The input torque may be reduced by changing the retard amount of the ignition timing, decreasing the fuel injection amount, further decreasing the torque amplification factor in the torque converter, or performing a combination of these.

In the reverse prohibition control, the pressure is released from the frictional engagement device for setting the reverse gear and the pressure is maintained in the released state. Instead, the shift lever is locked so that the shift lever cannot be set to the R range. It may be performed by doing.

Further, in the control shown in FIGS. 6 and 7, whether or not the engine output is excessive is determined based on the engine speed and the throttle opening. This determination is made based on one of the engine speed and the throttle opening. This may be performed, or may be performed based on the value detected by the torque sensor.

[0033]

As is apparent from the above description , claim 1
According to the control device of the invention, when the torque such as the input torque from the engine or the transmission torque to the main transmission portion that substantially sets the reverse speed cannot be reduced, the torque applied to the friction engagement device is reduced. Since the setting of the reverse gear, which is the largest reverse gear, is prohibited, it is possible to prevent a decrease in durability due to excessive slippage or wear of the friction engagement device. Especially claims
In the control device according to the second aspect, whether the line pressure is controlled to be increased
The frictional engagement device against the torque applied to the frictional engagement device
Insufficient torque capacity is prevented and the frictional engagement device is
To prevent deterioration of durability due to excessive sliding and abrasion
Can be Further, according to the control device of the invention of claim 3,
If the input torque cannot be reduced,
The sub-transmission that is set is set to the high speed stage, and
Since the effect of increasing the torque is suppressed or limited, the friction
Reduce the torque applied to the frictional engagement device to prevent excessive slippage and
Prevents deterioration of durability due to wear
You.

[Brief description of the drawings]

FIG. 1 is a block diagram showing in principle a control device of the present invention.

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

FIG. 3 is a skeleton diagram illustrating an example of a gear transmission mechanism.

FIG. 4 is an operation table of the automatic transmission shown in FIG. 3;

FIG. 5 is a hydraulic circuit diagram illustrating an example of a device for performing reverse prohibition control.

FIG. 6 is a part of a flowchart showing a control routine.

FIG. 7 is another part of a flowchart showing a control routine.

FIG. 8 is a map of a timer reference value.

FIG. 9 is a flowchart illustrating an example of fail-safe control when the torque is reduced by reducing the input torque and upshifting the subtransmission unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control device 2 Friction engagement device 3 Automatic transmission 4 Torque reduction means 6 Torque reduction impossible detection means 7 Reverse gear prohibition means

──────────────────────────────────────────────────続 き Continuing on the front page (72) Atsushi Tabata 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Masahiro Hayabuchi 10 Takane Fujii Town, Anjo City, Aichi Prefecture Aisin AW Inside (72) Inventor Masahiko Ando 10 Takane, Fujii-machi, Anjo, Aichi Prefecture Inside Aisin AW Co., Ltd. (72) Inventor Kazuma Tsukamoto 10 Takane, Fujii-machi, Anjo, Aichi Aisin A JP-A-2-248767 (JP, A) JP-A-61-105228 (JP, A) JP-A-62-149524 (JP, A) JP-A-55-87626 (JP) , A) (58) Field surveyed (Int. Cl. ⁶ , DB name) F16H 59/00-61 / 12,61 / 16-61/2 4,63 / 40-63/48 B60K 41/00-41 / 28 F02D 29/00-29/06

Claims (3)

(57) [Claims] 1. An automatic transmission having a gear transmission mechanism set to a plurality of shift speeds including a reverse speed by engaging or disengaging a plurality of friction engagement devices. when setting the controlling and reverse gear, and a control device for an automatic transmission having a torque reducing means for reducing the torque applied to the friction engagement device is engaged to set the rear Susumudan, the torque a torque reduction not detecting means for detecting a state that can not be reduced, the engagement of this when the torque reduction not detecting means detects that not be reduced torque, is engaged to set the reverse stage frictional engagement device A control device for an automatic transmission, comprising: a reverse gear prohibiting means for prohibiting a combination. 2. A method for engaging or releasing a plurality of friction engagement devices.
By setting it to multiple speeds including the reverse
Automatic transmission having a gear transmission mechanism
Controls engagement and disengagement of coupling device and sets reverse gear
A friction engagement device that is engaged when setting the reverse gear
Self-equipped with torque reduction means for reducing the torque applied to
In a control device for a dynamic transmission, A torque reduction failure for detecting a state where the torque cannot be reduced.
The detectable means and the torque reduction impossible detecting means reduce the torque.
When it is detected that the reduction cannot be performed, the friction engagement device is engaged.
Line pressure, which is the source pressure of hydraulic pressure for
Automatic pressure-equipped with an in-pressure booster
Transmission control device. 3. The output of an auxiliary transmission portion capable of shifting between high and low speeds.
Main transmission section that can set reverse speed and multiple forward speeds
Automatic transmission with a gear transmission mechanism connected to
Of the friction engagement device for setting each gear position.
When controlling reverse and release and setting the reverse gear,
Input torque reduction to reduce the torque input to the speed mechanism
In a control device for an automatic transmission having means, An input torque for detecting a state where the input torque cannot be reduced;
Torque reduction impossible detecting means and the input torque reduction impossible detecting means.
If the stage detects that it cannot reduce the input torque,
Sub-transmission unit control means for setting the sub-transmission unit to a high speed stage.
A control device for an automatic transmission, comprising: