JP2013122263A - Clutch control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clutch control device for an automatic transmission which can quickly completes a shift to a start gear without causing a gear squeak and a shock by properly performing double clutch operation in starting a vehicle.SOLUTION: A gear-shiftable point ST0 is set in advance with a dog phase at a clutch side as a shiftable clutch stroke by the transmission of an engine driving force. It is considered that a gear change becomes possible at a time point when a clutch stroke ST reaches a gear-change possible point ST0 without determining that the gear change has become possible on the basis of a clutch rotation speed Nc which increases by clutch connection, and the gear change is executed by controlling a clutch device 2 in the cutting direction.

Description

  The present invention relates to a clutch control device for an automatic transmission, and more particularly, to control a clutch that performs a double clutch operation to prevent a dog from hitting a sync mechanism when the automatic transmission is switched to a starting position for vehicle start. Relates to the device.

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. As this type of automatic transmission, for example, an automatic transmission in which a planetary gear mechanism is combined with a torque converter, a continuously variable transmission such as a belt type, or the like, a conventional mechanical manual transmission is used as a base. There is an automatic transmission in which clutch operation associated with operation and shift is automated by an actuator.
In an automatic transmission based on such a manual transmission, a target shift 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 is applied to achieve the target shift stage. The gear stage of the transmission is switched while connecting and disconnecting. For example, an automatic transmission has been proposed in which a double clutch operation is automatically executed for the purpose of reducing the burden on the synchro mechanism when performing a downshift accompanying deceleration of the vehicle (see, for example, Patent Document 1).

Double clutch operation is performed by first disengaging the clutch to make the gear position neutral, connecting the clutch once, hitting the accelerator, disengaging the clutch, then switching the gear position and then reconnecting the clutch. The As is well known, the synchro mechanism achieves the target shift stage by meshing the dogs on the clutch side and the drive wheel side after the rotation is synchronized by friction. The turning of the accelerator in the clutch connected state plays a role of raising the rotation of the dog on the clutch side together with the engine, thereby roughly synchronizing the rotation with the dog on the driving wheel side and reducing the burden on the synchro mechanism.
By the way, when the stopped vehicle is started, the transmission is switched to the starting stage (for example, second gear) in the clutch disengaged state (this operation may be referred to as gearing in the following description), and then the vehicle is connected by clutch connection. Is starting. Switching to the starting stage is performed when the clutch on the synchro mechanism and the dog on the drive wheel side are both stopped, so there is no need for rotational synchronization at that point. When you are, you may become unable to mesh. In particular, in a square tooth-shaped dog, the mountains easily face each other, and the frequency at which they cannot mesh is high.
In such a case, if the clutch is slightly connected and the phase of the dog on the clutch side is changed by the driving force of the engine, the dogs can be engaged with each other. The technique of Document 1 cannot deal with it. Therefore, when switching to the starting stage, a double clutch operation is performed in a stopped state according to the following procedure.

FIG. 5 is a time chart showing the control state of the double clutch operation when gearing to the starting stage when the vehicle starts in the prior art.
When the start determination is made by depressing the accelerator, first, the clutch is started to operate in the connecting direction, and accordingly, the clutch stroke ST (the amount of operation in the clutch connecting direction) increases to exceed the half clutch starting point ST1 ( Point a). At this time, the clutch rotation speed Nc (rotation speed on the clutch output side) starts increasing due to transmission of the driving force from the engine, and the phase of the dog on the clutch side changes in the transmission. When the clutch stroke ST reaches a predetermined hold point ST2 set on the connection side with respect to the half-clutch start point ST1, the hold point ST2 is held (point b).
Thereafter, when it is detected by the rotational speed sensor that the clutch rotational speed Nc has reached a preset gear-engageable determination value Nc0 (point c), the dogs can mesh with each other due to the phase change of the dog on the clutch side. Then, it is considered that gears can be engaged (hereinafter referred to as “gearing possible determination”), and the clutch is started to operate in the disconnection direction from the hold point ST2. When the clutch stroke ST is reduced to the half-clutch start point ST1 and the transmission of the engine driving force is stopped (point d), the gear engagement is started and the shift is completed. The clutch rotational speed Nc continues to increase for a while after the half-clutch starting point ST1, and then starts to decrease (point e).

Japanese Patent No. 3997741

As described above, in order to mesh the dogs whose mountains are facing each other by the double clutch operation when the vehicle is stopped, it is sufficient to slightly rotate the dog on the clutch side by changing the phase of the clutch by transmitting the engine driving force. is there. On the other hand, if the engine driving force is too large, the dog on the clutch side excessively rises, and even if rotation synchronization is performed by the synchro mechanism, gear squeal and shock occur when the gear is engaged. Further, if the dog waits until the rotation of the dog decreases as a countermeasure against excessive increase in rotation, the gear setting time is extended and the vehicle start is delayed.
Therefore, in FIG. 5, starting gear engagement immediately after the point a at which the clutch stroke ST has reached the half-clutch start point ST1 (slightly transmitting the driving force) by controlling the clutch in the direction in which the clutch is engaged, It is most desirable from the viewpoint of restraint and shortening of gear setting time.

In the above-described prior art, it is determined whether the gear can be engaged based on the detection of the rotational speed sensor, but the rotational speed sensor has a lower limit of the detection region. In view of the fact that the clutch rotational speed Nc starts to increase after the clutch stroke ST reaches the half-clutch starting point ST1, even if the gear-engageable determination value Nc0 is set at the lower limit of the sensor detection region, the clutch rotational speed Nc enters the sensor detection region and can determine whether the gear can be engaged based on the gear engagement possible determination value Nc0 at a time point c that is significantly delayed from the half clutch start point ST1. For this reason, in the prior art, gearing must be started at a point d where transmission of the engine driving force after the point c is exceeded, and a delay in starting the vehicle cannot be avoided due to the extension of the gearing time.
Moreover, since the clutch rotational speed Nc continues to increase while the clutch stroke ST is held at the hold point ST2, gear engagement is performed while the dog-side rotation on the clutch side is high. Therefore, there is a possibility that gear squeal and shock may occur, and as a countermeasure against this, when waiting until the dog rotates down, the gear setting time is further extended.
The present invention has been made to solve such problems, and the object of the present invention is to appropriately execute a double clutch operation at the time of vehicle start-up and thereby quickly start the gear without causing gear noise or shock. It is an object of the present invention to provide a clutch control device for an automatic transmission capable of starting a vehicle after completing the switching to.

  In order to achieve the above object, the invention according to claim 1 is directed to operating the clutch in the connecting direction by an actuator controlled by the clutch control means when the transmission is switched to the starting stage to start the stopped vehicle. The engine drive force is transmitted to the transmission side, the dog on the clutch side of the starting stage is rotated so that it can mesh with the dog on the drive wheel side, and then the double clutch operation is performed to disconnect the clutch by the actuator, and then In the clutch control device for an automatic transmission that performs switching to the starting stage at the time, when the clutch control means is operated in the clutch connecting direction by the actuator, the amount of operation of the actuator is preliminarily determined by the transmission of the engine driving force on the clutch side. Continue to operate the clutch until it reaches the gear settable point where the dog phase is set as a variable value. When the operation amount of the eta reaches the gear engagement can point it is to operate the clutch in the cutting direction.

According to a second aspect of the present invention, in the first aspect of the present invention, a gear-possible point setting means for setting the gear-possible point to a larger value as the oil temperature of the transmission is lower is provided. The clutch is operated by the actuator based on the gear-possible point set by the means.
According to a third aspect of the present invention, in the first or second aspect, the gear settable point setting means for setting the gear settable point to a larger value as the number of retry operations to be retried when the switching to the starting stage is impossible increases. And the clutch control means operates the clutch by the actuator based on the gear-possible point set by the gear-possible point setting means.
According to a fourth aspect of the present invention, in the first aspect, when the clutch control means operates the clutch in the disengagement direction when the operation amount of the actuator reaches the gear-engageable point by the operation in the clutch engagement direction, The clutch is also operated in the disengagement direction when the rotational speed of the motor reaches a preset gear-possible determination value.

According to a fifth aspect of the present invention, in the second aspect, the clutch control means switches to the starting stage in spite of executing the clutch operation based on a large gear-engageable point set corresponding to the low oil temperature of the transmission. When it is impossible, the operation in the direction of clutch engagement is continued until the dog's rotation speed on the clutch side reaches a preset gear-engageable determination value, and it is determined that the gear-engageable determination value has been reached. The clutch is operated in the disengagement direction.
According to a sixth aspect of the present invention, in the third aspect, when the clutch control means is unable to switch to the starting stage even though the number of retry operations reaches the upper limit, the rotational speed of the dog on the clutch side is preset. The operation in the clutch engagement direction is continued until the gear-engageable determination value is reached, and when it is determined that the gear-engageable determination value is reached, the clutch is operated in the disengagement direction.

As described above, according to the clutch control device for an automatic transmission of the first aspect of the present invention, when the double clutch operation is performed at the time of switching to the starting stage at the time of starting the vehicle, the operation amount of the actuator is set to a preset gear setting. The clutch is operated in the connecting direction until the possible point is reached, and the clutch is operated in the disconnecting direction when the operation amount reaches the point where the gear can be engaged.
That is, using the operation amount of the actuator with respect to the clutch as an index, it is considered that switching to the starting stage (gearing) becomes possible when the operation amount reaches the gear-possible point. Therefore, there is a delay in determining whether gears can be engaged due to the limitation of the sensor detection area, as in the prior art for determining whether gears can be engaged based on the rotational speed (clutch rotational speed) of the dog on the clutch side detected by the rotational speed sensor. do not do.
Therefore, according to the present invention, the switching to the starting stage can be started at a significantly faster timing, and thus the vehicle can be started by quickly completing the switching to the starting stage. In addition, since the clutch is operated in the disengagement direction when the gear-engageable point is reached, excessive rotation of the dog on the clutch side can be suppressed, thus preventing gear noise and shock when switching to the starting stage. be able to.

According to the clutch control device for an automatic transmission of the invention of claim 2, in addition to claim 1, the gear-engageable point is set to a larger value as the oil temperature of the transmission is lower, and based on the gear-engageable point. The clutch was operated.
Therefore, when the engine driving force is transmitted, the clutch side dog tends to be difficult to rotate. At low oil temperatures, the amount of operation of the actuator increases based on a large gear-engageable point. Switching to the starting stage by meshing the dogs becomes possible. On the other hand, at high oil temperatures, where the dog on the clutch side tends to increase in rotation, the amount of operation of the actuator decreases based on the small gear-engageable points, so excessive rotation of the dog is suppressed and gear noise and shock Is avoided in advance. Therefore, the double clutch operation can always be appropriately executed and switched to the starting stage regardless of the oil temperature fluctuation of the transmission.

According to the clutch control device for an automatic transmission of the invention of claim 3, in addition to claim 1 or 2, the gear-engageable point is set to a larger value as the number of retry operations increases, and the gear-engageable point The clutch is operated based on the above.
Therefore, each time the retry operation is repeated, the operation amount of the actuator increases, and accordingly, the driving force transmitted from the engine also increases sequentially. Therefore, at any point in time of the retry operation, the phase of the clutch side dog changes due to the transmission of the engine driving force and the shift to the gear position is completed, so it is possible to reliably avoid troubles such as inability to start. it can.
According to the clutch control apparatus for an automatic transmission according to a fourth aspect of the present invention, in addition to the first aspect, the clutch operation control based on the dog rotation speed is executed in addition to the clutch operation control based on the gear-engageable point. I did it. Therefore, even if it is not determined that the gear can be engaged based on the gear-engageable point, it is determined that the gear can be engaged based on the dog rotation speed, so that the gear engagement time can be further shortened and the vehicle can be started quickly. be able to.

According to the clutch control device for an automatic transmission according to the fifth aspect of the present invention, in addition to the second aspect, when the clutch is operated based on a large gear-engageable point and cannot be switched to the starting stage, The operation in the clutch connection direction is continued until the dog rotation speed reaches a predetermined gear-engageable determination value. When the dog rotation speed reaches the gear-engageable determination value, the clutch is operated in the disengagement direction.
Therefore, when it is impossible to switch to the starting stage, the operation in the clutch engagement direction is continued until the rotational speed of the dog on the clutch side reaches the gear-engageable determination value. For this reason, the engine driving force is more reliably transmitted to the transmission side, and the switching to the starting stage can be completed more reliably.
According to the clutch control apparatus for an automatic transmission of the sixth aspect of the invention, in addition to the third aspect, when the number of retries reaches the upper limit and the switching to the starting stage is impossible, the rotation of the dog on the clutch side is performed. The operation in the clutch engagement direction is continued until the speed reaches a predetermined gear-engageable determination value, and when the speed reaches the gear-engageable determination value, the clutch is operated in the disengagement direction.
Therefore, when it is impossible to switch to the starting stage, the operation in the clutch engagement direction is continued until the rotational speed of the dog on the clutch side reaches the gear-engageable determination value. For this reason, the engine driving force is more reliably transmitted to the transmission side, and the switching to the starting stage can be completed more reliably.

1 is an overall configuration diagram showing a track drive system to which a clutch control device for an automatic transmission according to an embodiment is applied. It is a time chart which shows the control condition of the double clutch operation at the time of gearing in the start stage at the time of vehicle start in an embodiment. It is a figure which shows the control map for calculating the gear possible point based on the oil temperature (retry frequency) of a transmission. It is a time chart which shows the control condition of the clutch stroke for every retry at the time of double clutch operation. It is a time chart which shows the control condition of the double clutch operation at the time of gearing in the start stage at the time of vehicle start in prior art.

[First Embodiment]
A first embodiment of a clutch control device for an automatic transmission embodying the present invention will be described below.
FIG. 1 is an overall configuration diagram showing a track drive system to which a clutch control device for an automatic transmission according to this embodiment is applied.
A vehicle is equipped with a diesel engine (hereinafter referred to as an engine) 1 as a driving power source. An input shaft 3a of an automatic transmission (hereinafter simply referred to as a transmission) 3 is connected to an output shaft 1b of the engine 1 via a clutch device 2. The rotation of the engine 1 is transmitted to the transmission 3 when the clutch device 2 is connected. It has come to be. The transmission 3 is based on a manual transmission having six forward speeds and one reverse speed. As described below, the gear shifting operation and the connecting / disconnecting operation of the clutch device 2 accompanying the gear shifting are automated. It is a thing.

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. An air cylinder 8 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 air cylinder 8 via an air passage 10 in which an electromagnetic valve 9 is interposed.
When the solenoid valve 9 is opened, compressed air is supplied from the air tank 11 to the air cylinder 8 (actuator) via the air passage 10, and the air cylinder 8 is activated to separate the clutch plate 5 from the flywheel 4 via the outer lever 7. Thus, the clutch device 2 is switched from the connected state to the disconnected state. On the other hand, when the solenoid valve 9 is closed, the air cylinder 8 stops operating due to the stop of the supply of compressed air, so that the clutch plate 5 is pressed against the flywheel 4 by the pressure spring 6, and thereby the clutch device 2 is released from the disconnected state. Switch to connected state. As described above, the air cylinder 8 is operated in accordance with the opening and closing of the electromagnetic valve 9 so that the clutch device 2 can be automatically connected and disconnected.

  The transmission 3 is provided with a gear shift unit 14 for switching the gear stage. Although not shown, the gear shift unit 14 includes a plurality of air cylinders that operate shift forks corresponding to the respective gear stages in the transmission 3, and It incorporates multiple solenoid valves that actuate the air cylinder. The gear shift unit 14 is connected to the above-described air tank 11 through the air passage 12, and compressed air from the air tank 11 is supplied to the corresponding air cylinder according to opening and closing of each solenoid valve, and the air cylinder is operated. When the corresponding shift fork is switched, the gear position of the transmission 3 is switched according to the switching operation. As described above, the air cylinder is operated in accordance with the opening / closing of the electromagnetic valve of the gear shift unit 14, and the transmission 3 can be automatically operated for shifting.

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 transmission 3 is performed.
On the input side of the ECU 21 are an engine rotation speed sensor 22 that detects the rotation speed Ne of the engine 1, a clutch rotation speed sensor 23 that detects the rotation speed (clutch rotation speed Nc) of the input shaft 3a of the transmission 3, and a driver's seat. A lever position sensor 24 that detects the switching position of the provided change lever 13, a gear position sensor 25 that detects the gear position of the transmission 3, an accelerator sensor 27 that detects the operation amount Acc of the accelerator pedal 26, and the output of the transmission 3 A vehicle speed sensor 28 provided on the shaft 3b for detecting the output shaft rotational speed Vss (correlating with the vehicle speed V), a brake switch 30 for detecting the operation of the foot brake 29, and the clutch stroke ST (by the air cylinder 8) of the clutch device 2 Sensors such as a stroke sensor 31 for detecting the operation amount in the connecting direction of the clutch device 2 are connected. There.

  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). . In addition, you may make it provide ECU for engine control separately from ECU21, for example, without controlling comprehensively by single ECU21 in this way.

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 Acc 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 transmission mode when the lever position sensor 24 detects that the change lever 13 is switched to the D range, and based on the accelerator operation amount Acc and the vehicle speed V detected by the vehicle speed sensor 28, the ECU 21 The target gear position is calculated from the shift map that is not. Then, while opening and closing the electromagnetic valve 9 of the clutch device 2 and connecting and disconnecting the clutch device 2 by the air cylinder 8, the predetermined electromagnetic valve of the gear shift unit 14 is opened and closed and the corresponding shift fork is switched by the air cylinder. Thus, the shift speed is switched to the target shift speed (shift control means), thereby causing the vehicle to always travel with an appropriate shift speed.

By the way, when the driver depresses the accelerator pedal 26 to start the stopped vehicle, the ECU 21 performs so-called gearing for switching the transmission 3 to the starting stage (for example, second gear) in the clutch disengaged state. The clutch device 2 is connected to start the vehicle. When gears are engaged, the double clutch operation is executed (clutch control means) on the assumption that the dog crests at the starting stage face each other and cannot engage with each other.
However, as described in [Problems to be Solved by the Invention], in the conventional technology for determining whether the gear can be engaged based on the detection of the rotational speed sensor, a determination delay occurs due to the limitation of the sensor detection area, and the gear engagement time is extended. There was a problem that the sound was changed, gears squeezed and shocks occurred.

Here, the present inventor has focused on the point that the increase in the clutch rotational speed Nc required for the double clutch operation at the time of stopping is different from the rotation increase required for the double clutch operation while the vehicle is traveling. That is, in the double clutch operation while the vehicle is running, it is necessary to increase the rotational speed of the dog on the clutch side to the rotational range of the dog on the drive wheel side for rotational synchronization. For this purpose, the clutch based on the detection of the rotational speed sensor is required. The determination of the rotational speed Nc is essential.
On the other hand, in double clutch operation when the vehicle is stopped, if the dog phase on the clutch side is changed slightly, the confrontation between the peaks is surely resolved. do not have to. Therefore, in the present embodiment, the gear can be engaged by transmitting the engine driving force at the time when the clutch device 2 is operated in the connecting direction for the preset clutch stroke ST without determining whether the gear can be engaged based on the sensor detection. It is assumed that the gear was put in. Hereinafter, the gear setting process to the starting stage executed by the ECU 21 when starting the stopped vehicle will be described.

FIG. 2 is a time chart showing a control state of the double clutch operation when the gear is put into the starting stage when the vehicle starts.
When the start determination is made by depressing the accelerator, the ECU 21 first starts to operate the clutch device 2 in the connecting direction, and accordingly, the clutch stroke ST (the amount of operation in the connecting direction) increases and the half clutch starting point ST1. (Point A). At that time or immediately after that, the clutch rotational speed Nc starts to increase due to the transmission of the driving force from the engine 1. The operation in the connecting direction is continued until the clutch stroke ST reaches the gear-possible point ST0 set on the connection side from the half-clutch start point ST1 (clutch control means). Point B), the operation direction of the clutch device 2 is reversed to start operating in the disconnection direction (clutch control means).

The gear-possible point ST0 is a value obtained by a test performed in advance as the minimum clutch stroke ST that can change the phase of the dog on the clutch side by transmitting the engine driving force via the clutch device 2. That is, when the clutch stroke ST increases and exceeds the half-clutch start point ST1, the engine driving force begins to be transmitted to the transmission 3 side via the clutch device 2 at the same time or immediately after this, and accordingly the dog on the clutch side The rotation starts and its phase begins to change. The gear-possible point ST0 is set as a value obtained by adding a slight margin on the connection side to the clutch stroke ST at the start of dog rotation.
Therefore, when the clutch stroke ST reaches the gear-possible point ST0, the phase of the dog on the clutch side is reliably changed by the transmission of the engine driving force, and the dogs can be engaged with each other.
In this embodiment, since there is no correlation between the open / close state of the electromagnetic valve 9 that controls the air cylinder 8 and the clutch stroke ST, the clutch stroke ST is engaged with the gear engagement based on the detection information from the clutch stroke ST sensor. Although it is determined that the possible point ST0 has been reached, the present invention is not limited to this. For example, in a configuration in which the clutch device 2 is operated by an electromagnetic actuator, a correlation is established between the excitation current of the actuator and the clutch stroke ST. Therefore, it may be determined that the clutch stroke ST has reached the gear-engageable point ST0 based on the excitation current supplied to the actuator without referring to the sensor information.

  The clutch stroke ST gradually decreases due to the operation of the clutch device 2 in the disengagement direction, and when it is determined that the clutch stroke ST has fallen below the half-clutch start point ST1 based on the detection information from the clutch stroke sensor (point C), gear engagement is started. The shift is completed. On the other hand, as the clutch device 2 is operated in the disengagement direction, the clutch rotational speed Nc turns in a decreasing direction and decreases to 0 during the gear engagement operation.

As described above, the clutch control device of the automatic transmission 3 according to the present embodiment does not necessarily require the determination of whether the gear can be engaged based on the detection of the rotation speed sensor in the double clutch operation at the time of starting the vehicle. We focused on the points that occurred. Then, without determining whether the gear can be engaged based on the sensor detection, it is considered that the gear can be engaged when the clutch stroke ST reaches a predetermined gear-possible point ST0 by the operation in the connecting direction of the clutch device 2, and thereafter When the clutch stroke ST decreases to the half clutch start point ST1, the gear engagement is started.
Therefore, the timing for starting gear engagement is the time point C at which the clutch stroke ST has decreased to the half clutch start point ST1 after reaching the gear engagement possible point ST0. In the prior art shown in FIG. 5, since it is impossible to determine whether the gear can be engaged until the rising clutch rotational speed Nc enters the sensor detection region, gear engagement can be started only at the subsequent point d. Then, in this embodiment, gearing can be started at a significantly faster timing. As a result, the gear-setting time can be shortened, and thus the vehicle can be started by quickly switching to the starting stage.

Further, as a result of the control of the clutch stroke ST, the clutch stroke ST exceeds the half-clutch start point ST1 (transmits driving force) for a very short time, and the clutch rotational speed Nc can engage the dog during that time. It will only rise to the minimum necessary. For this reason, it is possible to prevent gear squealing and shock when gears are engaged due to excessive rotation of the clutch dog. In other words, since there is no need to wait until the dog rotates, there is no possibility of extending the gear setting time.
On the other hand, in order to reduce the problem as much as possible while adopting the control method of the prior art that determines whether gears can be engaged based on sensor detection, an expensive rotation speed sensor with a lower detection area is required. In the case of this embodiment, since it can be implemented without referring to the clutch rotational speed Nc, the rotational speed sensor itself is not originally required. Further, even if sensor information is required for other clutch control, it is not necessary to use a rotation speed sensor with a lower limit of the detection area, which is advantageous in terms of manufacturing cost.

By the way, in addition to the control method of the present invention shown in FIG. 2, the conventional control method shown in FIG. 5 may be used in combination. For example, when the clutch-side dog has a tendency to easily rotate and increase with respect to an increase in the clutch stroke ST, the rotational speed in the conventional method is reached before the clutch stroke ST reaches the gear-engageable point ST0 in the control method of the present invention. It may be determined that the gear can be engaged based on the detection of the sensor. In such a case, since it is determined that the gear can be put on the basis of the conventional method prior to the gear setting judgment by the control of the present invention, the gear setting time can be further shortened to realize a quick vehicle start. Can do.
On the other hand, even when the clutch stroke ST is similarly controlled and the same driving force is transmitted to the transmission 3 side when the double clutch is operated, the clutch side is caused by the change in the oil viscosity according to the oil temperature in the transmission 3. The dog's rotation is different. For this reason, when the clutch stroke ST is controlled based on the single gear-possible point ST0, the gear cannot be engaged due to a shortage of the clutch stroke ST, or conversely, an excessive clutch stroke ST may cause a gear ringing or a sign of shock. there's a possibility that. Therefore, the gear-possible point ST0 may be set according to the oil temperature. Hereinafter, another example will be described as the second embodiment.

[Second Embodiment]
The overall configuration of the clutch control device of the automatic transmission 3 according to the present embodiment is the same as that of the first embodiment shown in FIG. 1, and the difference is the setting of the gear-engageable point ST0 as described above. is there. Therefore, common constituent parts are denoted by the same member numbers, description thereof is omitted, and differences are mainly described.
FIG. 3 is a diagram showing a control map for calculating the gear-possible point ST0 based on the oil temperature of the transmission 3.
As shown in the figure, the map is set to a characteristic in which a larger value is calculated as the gear-engageable point ST0 as the oil temperature is lower (gear-engageable point setting means). Therefore, when the oil temperature is low, such as in winter, a large value gear-possible point ST0 is calculated from the map, and conversely, when the oil temperature is high, such as in summer, a small value gear-possible point ST0 is calculated. The clutch stroke ST is controlled based on the possible point ST0.

  Therefore, when the oil temperature is low, the oil viscosity becomes high and the dog on the clutch side tends to hardly rotate up. However, the increase in the clutch stroke ST makes it possible for the dog to reliably rotate up and engage with each other by engaging the dogs. Become. On the other hand, when the oil temperature is high, the oil viscosity tends to be low and the dog tends to rotate and rise, but by reducing the clutch stroke ST, excessive rotation of the dog is suppressed and gear squeal and shock are avoided. Therefore, the double clutch operation can always be appropriately performed regardless of the oil temperature fluctuation of the transmission 3, and the various functions and effects described in the first embodiment can be reliably achieved.

By the way, even when the clutch stroke ST is controlled based on the gear setting point ST0 where the oil temperature of the transmission 3 is low and the gear setting is large, the gear setting may not be completed. In such a case, the control method of the present invention shown in FIG. 2 may be switched to the conventional control method shown in FIG. According to the conventional method, since the clutch stroke ST is increased and held at the hold point ST2 until the clutch rotational speed Nc reaches the gear-engageable determination value Nc0, the engine driving force can be more reliably transmitted to the transmission 3 side. There is a feature. Therefore, even if the gearing is impossible with the control method of the present invention, the gearing can be completed according to the conventional method, and thus the gearing can be completed more reliably and the vehicle can be started by switching to the conventional method in this way. Benefits are gained.
On the other hand, there is a case where the gear cannot be engaged due to some factors other than the oil temperature of the transmission 3, and in this case, the gear cannot be engaged without changing the phase of the dog on the clutch side due to insufficient transmission of the engine driving force. Sometimes it falls into. Therefore, as a countermeasure in such a case, the transmission of the driving force may be sequentially increased by resetting the gear-possible point ST0 in the connection direction at every retry operation for retrying gear engagement. Will be described as a third embodiment.

[Third Embodiment]
FIG. 4 is a time chart showing the control status of the clutch stroke ST for each retry when the double clutch is operated according to this embodiment.
The gear-possible point ST0 for each retry is calculated from a preset map, and the map characteristics are shown in parentheses in FIG. The larger the number of retries, the greater the value that can be calculated as the gear setting possible point ST0 (gear setting point setting means). Therefore, every time a retry is repeated due to the inability to engage the gear, a large gear-possible point ST0 is calculated from the map, and the clutch stroke ST is controlled based on the gear-engageable point ST0.
For this reason, even when the clutch phase dog phase does not change and the gear cannot be engaged due to insufficient transmission of the engine driving force, the clutch stroke ST increases each time the retry operation is repeated. Along with this, the driving force transmitted from the engine 1 also increases sequentially. Therefore, at any time of the retry operation, the phase of the dog on the clutch side changes due to the transmission of the engine driving force and the gear engagement is completed, so that troubles such as inability to start can be reliably avoided.

In this embodiment, as shown in FIG. 3, a clutch engagement point ST3 in which a gear-possible point ST0 smaller than the half-clutch start point ST1 is set in the first retry operation and the clutch device 2 is completely connected in the fourth operation is shown. A gear-possible point ST0 corresponding to is set. However, the setting characteristics of these gear-engageable points ST0 can be arbitrarily changed.
Further, the present embodiment is combined with the second embodiment, and the gear-possible point ST0 is set according to the oil temperature of the transmission 3, and the gear-engageable point ST0 is increased every time the retry is performed. Good.

By the way, even if the clutch stroke ST is sequentially increased while repeating the retry operation as in the present embodiment, the gear engagement may not be completed. In such a case, when the number of retries reaches the upper limit, the control method of the present invention shown in FIG. 2 may be switched to the conventional control method shown in FIG. As described above, the conventional method of holding the clutch stroke ST at the hold point ST2 has a feature that the engine driving force can be more reliably transmitted to the transmission 3 side. Therefore, even if the gearing is impossible with the control method of the present invention, the gearing can be completed according to the conventional method, and thus the gearing can be completed more reliably and the vehicle can be started by switching to the conventional method in this way. Benefits are gained.
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.

1 Engine 2 Clutch device (clutch)
3 Automatic transmission 8 Air cylinder (actuator)
21 ECU (clutch control means, gear setting possible point setting means)

Claims (6)

When the transmission is switched to the starting stage to start the stopped vehicle, the engine driving force is transmitted to the transmission side by operating the clutch in the connecting direction by the actuator controlled by the clutch control means, and the starting stage An automatic transmission that rotates a clutch-side dog so that it can be engaged with a dog on the driving wheel side, performs a double-clutch operation to disengage the clutch by the actuator, and then switches to the starting stage. In the clutch control device of the machine,
In the clutch control means, when the actuator is operated in the clutch connection direction, the operation amount of the actuator is set in advance as a value that can change the phase of the dog on the clutch side by transmitting the engine driving force. The clutch control device for an automatic transmission, wherein the clutch operation is continued until a gear-engageable point is reached, and the clutch is operated in a disengagement direction when the operation amount of the actuator reaches the gear-engageable point. Gear setting point setting means for setting the gear setting point to a larger value as the oil temperature of the transmission is lower,
2. The clutch control device for an automatic transmission according to claim 1, wherein the clutch control means operates the clutch by the actuator based on a gear-possible point set by the gear-possible point setting means. A gear-possible point setting means for setting the gear-possible point to a larger value as the number of retry operations to be retried when the switching to the starting stage is impossible increases;
3. The clutch control device for an automatic transmission according to claim 1, wherein the clutch control means operates the clutch by the actuator based on a gear-possible point set by the gear-possible point setting means. .   The clutch control means operates the clutch in the disengagement direction when the operation amount of the actuator reaches the gear-engageable point by operation in the clutch engagement direction, while the rotation speed of the clutch dog is preset. 2. The clutch control device for an automatic transmission according to claim 1, wherein the clutch is operated in the disengagement direction even when the gear-engageable determination value is reached.   The clutch control means is configured such that when the clutch operation is performed based on a large gear-engageable point set corresponding to a low oil temperature of the transmission but cannot be switched to the starting stage, the clutch side The operation of the clutch is continued until the dog rotation speed reaches a predetermined gear-engageable determination value, and the clutch is disconnected when it is determined that the gear-engageable determination value is reached. 3. The clutch control device for an automatic transmission according to claim 2, wherein the clutch control device is operated in a direction.   When the clutch control means is unable to switch to the starting stage even though the number of retry operations has reached the upper limit, the clutch-side dog rotation speed reaches a preset gear-engageable determination value. 4. The automatic transmission according to claim 3, wherein operation of the clutch in the connecting direction is continued until the clutch is operated, and the clutch is operated in the disengaging direction when it is determined that the gear-engageable determination value has been reached. Clutch control device.

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