JP2015045386A - Control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an automatic transmission, which can determine a gearing inability promptly, in the case where a gearing of a start stage fails during the stopping of a vehicle, to transit early to a retry operation so that a gearing duration can be shortened as a whole thereby to realize a smooth start of the vehicle.SOLUTION: When a stopping vehicle is started, a clutch device 2 is cut (at point a) by a clutch cylinder 8. When an input shaft rotation speed Nin drops to a gearing start determination value Nin1 (at point c), a gearing cylinder is activated. In the case where a limit time T elapses without a shift stroke Gst reaching a gearing end determination value Gst0 but where the input shaft rotation speed Nin drops to 0 (at point e), the operation is shifted to a retry operation by making a gearing inability determination.

Description

  The present invention relates to a control device for an automatic transmission.

2. Description of the Related Art In recent years, automatic transmissions that automatically switch gear positions according to the amount of accelerator operation by a driver, vehicle speed, and the like have become widespread not only in passenger cars but also in large vehicles such as trucks and buses. For example, this type of automatic transmission is based on a conventional stepped manual transmission in addition to a continuously variable transmission such as an automatic transmission in which a planetary gear mechanism is combined with a torque converter or a belt type. There is an automatic transmission in which an operation of switching gears and a connecting / disconnecting operation of a clutch device accompanying a shift are automated by an actuator.
In such an automatic transmission based on a manual transmission, a target gear stage is determined from the accelerator opening and the vehicle speed based on a predetermined shift map during traveling of the vehicle, and an appropriate clutch device is used to achieve the target gear stage. The gear position is switched while connecting / disconnecting. In addition, when the vehicle is stopped and switched from the N range to the D range for starting, a so-called gearing operation for switching the automatic transmission from the neutral position to the starting stage (for example, the second speed) is executed. Unlike gear shifting during driving, when the gear is engaged in the starting stage, the drive wheel side of the synchronizing mechanism provided at the starting stage is stopped when the vehicle is stopped, and the clutch apparatus side of the synchronizing mechanism is disconnected when the clutch apparatus is disconnected. Also suddenly drops and stops. For this reason, the dogs of the synchro mechanism may face each other and become unable to mesh.
In the conventional technology, if the gear engagement is not completed even after a predetermined time has elapsed since the start of the first gear engagement operation, it is determined that the gear cannot be engaged, and the retry operation is performed under conditions that facilitate gear engagement. It is repeating. In the retry operation, as described in Patent Document 1, for example, a half-clutch operation is performed, and the input shaft rotational speed of the automatic transmission once reduced to 0 is increased again, and then gearing is attempted.

JP 2013-122263 A

In a situation where the gear setting cannot be completed by the first gear setting operation, it is desirable to immediately make a determination that the gear cannot be set and shift to a retry operation. However, the conventional technology has a problem that since the timing for making the determination that the gear cannot be set is late, even if the gear setting is completed by a retry operation, the time required for gear setting as a whole is prolonged.
Specifically, as shown in the time chart of FIG. 3, when there is a gear engagement request to the starting stage by switching to the D range (point A in FIG. 3), the clutch device is first disengaged (in FIG. 3). Point B). When the clutch device is disconnected, the input shaft rotational speed Nin of the automatic transmission starts to decrease (point B in FIG. 3), and when the input shaft rotational speed Nin decreases to the gear engagement start determination value Nin1 (point C in FIG. 2), the gear The insertion cylinder operates with a low operating force (point C in FIG. 3).
If the gear engagement is not completed even after the first gear engagement time T1 has elapsed from the start of the gear engagement operation, the gear engagement cylinder is switched to a high operation force (point D in FIG. 3). Nevertheless, if the gear engagement is not completed even after the second gear engagement time T2 has elapsed, the gear engagement impossibility determination is made and the operation proceeds to the retry operation (point E in FIG. 3).
As is apparent from FIG. 3, the input shaft rotational speed Nin of the automatic transmission is rapidly reduced to zero with the disconnection of the clutch device. At this time, if the dogs of the synchro mechanism face each other and cannot mesh, there is almost no possibility that the relative position of the dogs will improve thereafter. However, in the conventional technique, the gear disengagement determination is not made until the timing (T1 + T2) that is much later than that, so that the first gear engagement operation is continued unnecessarily, and the required gear engagement time is prolonged. .
The present invention has been made to solve such a problem, and the object of the present invention is to promptly determine that the gear cannot be engaged when gearing to the starting stage fails while the vehicle is stopped. Thus, it is an object of the present invention to provide an automatic transmission control device that can shift to a retry operation at an early stage, thereby shortening the time required for gear setting as a whole and realizing a smooth start of the vehicle.

  In order to achieve the above object, the present invention connects a stepped transmission that achieves each shift stage by a synchro mechanism to a driving power source via a clutch, and performs a shift operation of the transmission and a clutch disconnection. When each of the contact operations is automated by the actuator and the stopped vehicle is started, the clutch is disengaged by each actuator driven and controlled by the gear setting control means, and the gear setting operation to the starting stage of the automatic transmission is executed. In addition, in a control device for an automatic transmission that repeats a retry operation when the gear-impossible determination means makes a gear-impossible determination due to a gear engagement failure, a rotational speed detection means that detects an input shaft rotational speed of the automatic transmission The gear-impossibility determining means includes a clutch disengagement without completing the gear-engagement when the gear-engaging operation is performed at the start of the vehicle. When the input shaft rotational speed detected by the rotational speed detecting means decreases to 0 and a preset time limit has elapsed thereafter, a determination is made that the gear cannot be engaged and the operation proceeds to a retry operation. .

  According to the present invention, when gearing to the starting stage fails while the vehicle is stopped, it is possible to promptly determine that gears cannot be engaged and to proceed to retry operation at an early stage, thereby reducing the total time required for gearing. The vehicle can be shortened and a smooth start of the vehicle can be realized.

1 is an overall configuration diagram showing a drive system of a track to which an automatic transmission control device of an embodiment is applied. It is a time chart which shows the execution condition of the gear setting operation and retry operation by the control apparatus of embodiment. It is a time chart which shows the execution condition of the gear setting operation and retry operation by a prior art.

Hereinafter, an embodiment of a control device for an automatic transmission embodying the present invention will be described.
FIG. 1 is an overall configuration diagram showing a track drive system to which an automatic transmission control device of this embodiment is applied.
A vehicle is equipped with a diesel engine (hereinafter referred to as an engine) 1 as a driving power source. The input shaft 3a of the automatic transmission 3 is connected to the output shaft 1b of the engine 1 via the clutch device 2, and the rotation of the engine 1 is transmitted to the automatic transmission 3 when the clutch device 2 is connected. . The automatic transmission 3 is based on a stepped manual transmission having six forward speeds and one reverse speed. As described below, the automatic transmission 3 includes a clutch device 2 associated with the speed change operation and the speed change. The connection / disconnection operation is automated.

The clutch device 2 is configured as a friction clutch that is connected to the flywheel 4 by press-contacting the clutch plate 5 with a pressure spring 6 and is disconnected by separating the clutch plate 5 from the flywheel 4. A clutch cylinder 8 (actuator) is connected to the clutch plate 5 via an outer lever 7, and an air tank 11 filled with compressed air is connected to the clutch cylinder 8 via an air passage 10 in which an electromagnetic valve 9 is interposed. Yes.
When the electromagnetic valve 9 is opened, compressed air is supplied from the air tank 11 to the clutch cylinder 8 via the air passage 10, and the clutch cylinder 8 is operated to separate the clutch plate 5 from the flywheel 4 via the outer lever 7. The device 2 is switched from the connected state to the disconnected state. On the other hand, when the solenoid valve 9 is closed, the clutch cylinder 8 stops operating due to the stop of the supply of compressed air, so the clutch plate 5 is pressed against the flywheel 4 by the pressure spring 6 and the clutch device 2 is disconnected from the disconnected state. Can be switched to. Thus, the clutch cylinder 8 is actuated according to the opening and closing of the electromagnetic valve 9, and the clutch device 2 can be automatically connected and disconnected.

The automatic transmission 3 is provided with a gear shift unit 14 for switching the gear position. Although not shown, the gear shift unit 14 includes a plurality of gear-engaging cylinders (actuators) that operate each gear position in the automatic transmission 3 in the gear-engaging direction, and a plurality of gear-release cylinders (actuators) that operate each gear position in the gear-releasing direction. Actuator) and a plurality of solenoid valves for operating each cylinder. The gear shift unit 14 is connected to the above-described air tank 11 via the air passage 12, and compressed air from the air tank 11 is supplied to a corresponding gear engagement cylinder or gear release cylinder according to opening and closing of each electromagnetic valve. As a result, the cylinder is operated to switch the corresponding shift fork, and the shift stage of the automatic transmission 3 is switched accordingly. As described above, the gear-carrying cylinder and the gear-canceling cylinder are operated in accordance with the opening and closing of the electromagnetic valve of the gear shift unit 14, so that the automatic transmission 3 can be automatically shifted.
In this embodiment, the operating force of the gearing cylinder can be controlled in two steps, high and low, and different operating forces are applied in the initial gearing operation and the subsequent retrying operation as will be described later.

In the passenger compartment, an input / output device (not shown), a storage device (ROM, RAM, etc.) for storing control programs and control maps, an ECU (control unit) equipped with a central processing unit (CPU), a timer counter, etc. 21 is installed, and comprehensive control of the engine 1, the clutch device 2, and the automatic transmission 3 is performed.
On the input side of the ECU 21, an engine rotation speed sensor 22 that detects the rotation speed Ne of the engine 1, an input shaft rotation speed sensor 23 (rotation speed detection means) that detects a rotation speed Nin of the input shaft 3 a of the automatic transmission 3, A lever position sensor 24 for detecting the operating position of the change lever 13 provided in the driver's seat, a shift stroke sensor 25 for detecting the shift stroke Gst (representing the gear position) of each shift stage of the automatic transmission 3, an accelerator pedal 26, an accelerator sensor 27 for detecting the operation amount θAcc, an output shaft rotational speed sensor 28 for detecting the rotational speed Nout (proportional to the vehicle speed V) of the output shaft 3b of the automatic transmission 3, and a brake for detecting the operation of the foot brake 29. Sensors such as a switch 30 and a clutch stroke sensor 31 for detecting the clutch stroke Cst of the clutch device 2 There has been connected.

  Further, the electromagnetic valve 9 of the clutch device 2 and the electromagnetic valves of the gear shift unit 14 are connected to the output side of the ECU 21, and the fuel injection valve of the engine 1 is connected (not shown). .

For example, the ECU 21 calculates a fuel injection amount to each cylinder of the engine 1 from a map (not shown) based on the engine rotation speed Ne detected by the engine rotation speed sensor 22 and the accelerator operation amount θAcc detected by the accelerator sensor 27. At the same time, the fuel injection timing is calculated from a map (not shown) based on the engine speed Ne and the fuel injection amount Q. Based on these calculated values, the engine 1 is operated while driving the fuel injection valves of the respective cylinders.
Further, the ECU 21 executes the automatic shift mode when the lever position sensor 24 detects that the change lever 13 is switched to the D range, and the output shaft rotation detected by the accelerator operation amount θAcc and the output shaft rotation speed sensor 28. Based on the speed Nout, a target shift speed is calculated from a shift map (not shown). Then, while opening / closing the electromagnetic valve 9 of the clutch device 2 and operating the clutch device 8 to be connected / disconnected by the clutch cylinder 8, the corresponding electromagnetic valve of the gear shift unit 14 is opened / closed and the corresponding shift is performed by the gear engagement cylinder and the gear release cylinder. Switch fork. As a result, the shift stage of the automatic transmission 3 is switched to the target shift stage, and the vehicle is always driven with an appropriate shift stage.

On the other hand, when the driver switches from the N range to the D range to start the stopped vehicle, the ECU 21 performs a gearing operation for switching the automatic transmission 3 to the starting stage (for example, the second speed). . Hereinafter, the gearing operation at the starting stage executed by the ECU 21 will be described.
FIG. 2 is a time chart showing the execution status of the gear engagement operation and the retry operation.
First, when there is a gear engagement request to the starting stage by switching to the D range (point a in FIG. 2), the clutch device 2 is disconnected. When the clutch device 2 is disconnected, the input shaft rotational speed Nin of the automatic transmission 3 starts to decrease (point b in FIG. 2), and when the input shaft rotational speed Nin decreases to a preset gear engagement start determination value Nin1 (FIG. 2). C), the gearing cylinder is operated with a low operating force. The above processing corresponds to the gear setting control means of the present invention.
Then, as shown by a broken line in FIG. 2, when the shift stroke Gst of the starting stage reaches a preset gear setting completion determination value Gst0, a gear setting completion determination is made. On the other hand, as indicated by the solid line in FIG. 2, the input shaft rotational speed Nin decreases to 0 (point d in FIG. 2) without the shift stroke Gst reaching the gear engagement completion determination value Gst0, and further, a preset limit is set. When the time T has elapsed, a determination is made that the gear cannot be engaged (point e in FIG. 2).
While the input shaft rotation speed Nin is decreasing, there is an appropriate rotational difference between the clutch device 2 side and the drive wheel side of the synchro mechanism, so that the dogs are easily meshed. Further, even if the rotation difference between the dogs disappears, the meshing is completed during the time limit T if the dogs are not facing each other. If the gearing is not completed even after the time limit T has elapsed, it can be considered that the dogs face each other and are unable to mesh, and there is almost no possibility that the relative position of the dogs will improve thereafter. Therefore, in such a case, it is determined that the gear cannot be engaged.
If the input shaft rotational speed sensor 23 has a detection error in the lower direction, there is a possibility that the gear-impossible determination is made before the actual input shaft rotational speed Nin decreases to zero. The time limit T also serves to prevent such a situation.
When it is determined that the gear cannot be engaged, the operation proceeds to a retry operation. First, the gear release cylinder is operated to return the starting stage to the neutral position. Next, the clutch device 2 is operated in the connecting direction (point f in FIG. 2), and is operated in the disconnecting direction after exceeding the half-clutch starting point. The input shaft rotational speed Nin of the automatic transmission 3 that once decreased to 0 increases again, and then starts decreasing. The reduction speed of the input shaft rotational speed Nin is adjusted by a brake provided on the counter shaft of the automatic transmission 3, but in the retry operation, the braking action is weakened and the rotational decrease is moderated as compared with the first gearing operation. . When the input shaft rotation speed Nin decreases to a preset gear engagement start determination value Nin2 (> Nin1) (point g in FIG. 2), the gear engagement cylinder is operated with a high operating force.
The above is one retry operation. This retry operation is performed for the first time by starting the gearing operation early based on the higher gearing start determination value Nin2, gradually decreasing the input shaft rotation speed Nin, and increasing the operating force of the gearing cylinder. It is executed under conditions that make gearing easier than gearing operation. FIG. 2 shows a case where the shift stroke Gst reaches the gear engagement completion determination value Gst0 by the retry operation and the gear engagement is completed.
On the other hand, in this retry operation, when the input shaft rotation speed Nin decreases to 0 and the time limit T has elapsed without completing the gear engagement, the gear engagement impossibility determination is again made and the retry operation is repeated. If the gear engagement is not completed even if the retry operation is repeated a preset number of times, the retry operation is executed with different control contents. For example, as in the prior art gearing operation shown in FIG. 3, the gearing operation may be continued for a predetermined time limit from the start of the gearing operation. In this case, the gearing cylinder operating time (gearing continuation time) is longer than the previous retrying operation, and the possibility of completing gearing is increased.
As described above, in the control device for the automatic transmission 3 according to the present embodiment, during the first gearing operation, gearing is performed during the period until the input shaft rotation speed Nin decreases to 0 and the time limit T elapses. When the operation is not completed, it is determined that the gear cannot be engaged and the operation is shifted to the retry operation. If the gear engagement is not completed even after this period, it can be considered that the dogs face each other and cannot mesh, and there is almost no possibility that the relative position of the dogs will improve thereafter. Therefore, by determining that the gear cannot be engaged when the time limit T has elapsed, it is possible to prevent the unnecessary gear engagement operation from being continued in a situation where the gear engagement cannot be completed (substantial gear engagement failure). As a result, if gearing to the starting stage fails while the vehicle is stopped, it is possible to promptly determine that gears cannot be engaged and shift to retry operation early, thereby shortening the overall gearing time required. Smooth start of the vehicle can be realized.
This is the end of the description of the embodiment, but the aspect of the present invention is not limited to this embodiment. For example, although applied to a truck in the above embodiment, the present invention is not limited to this and may be applied to a bus or a passenger car.
Moreover, in the said embodiment, although applied to the automatic transmission 3 based on the normal stepped manual transmission, it is not restricted to this. For example, the present invention may be applied to a so-called dual clutch type automatic transmission having two power transmission systems including an odd-numbered shift stage and an even-numbered shift stage.

1 Engine (Power source for running)
2 Clutch device (clutch)
3 Automatic transmission 8 Clutch cylinder (actuator)
21 ECU (gear setting control means, gear setting impossible determination means)
23 Input shaft rotational speed sensor (rotational speed detection means)

Claims (1)

A stepped transmission that achieves each shift stage by a synchro mechanism is connected to a driving power source via a clutch, and the shift operation of the transmission and the connection / disconnection operation of the clutch are each automated by an actuator. When starting the vehicle in the vehicle, the clutches are disengaged by the actuators controlled by the gear setting control means to execute the gear setting operation to the starting stage of the automatic transmission. In the automatic transmission control device that repeats the retry operation when the inability to enter is determined by the inability to enter the gear,
A rotation speed detecting means for detecting an input shaft rotation speed of the automatic transmission;
The gear disengagement determining means is the input shaft rotation speed detected by the rotation speed detecting means with the disengagement of the clutch without completing gear engagement when executing the gear engagement operation at the start of the vehicle. The automatic transmission control device is characterized in that when the time limit decreases to 0 and a preset time limit elapses thereafter, it is determined that the gear cannot be engaged and the operation proceeds to the retry operation.

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