DE102005054623B4 - Method for driving a synchronization device in a shift operation in an automated transmission and synchronization device of an automated transmission, in particular for carrying out the method - Google Patents

Abstract

Method for driving a synchronization device in a shift operation in an automated transmission, wherein an expected synchronous duration (TSync) is determined as a function of a respective to be synchronized differential speed (Δω) between a loose wheel of the gear to be interpreted and a loose wheel of the gear to be engaged, and that one for Synchronizing required synchronous force (FSync) after the elapsed synchronous duration (TSync) is changed, characterized in that the synchronous duration (TSync) determined after locking the synchronizer and a timer is started, and that the synchronous force (FSync) after the elapse of the detected synchronous duration (TSync) is increased linearly.

Description

The present invention relates to a method for driving a synchronizer in a shift operation in an automated transmission. Furthermore, the present invention also relates to a synchronization device in an automated transmission, in particular for carrying out the proposed method.

The German patent application DE 199 07 141 A1 discloses an electronically controlled shift system for manual transmissions, wherein a shift time can be determined according to a predetermined shift force.

The DE 195 26 273 C2 discloses methods for switching force modulation, for example, to achieve a short switching time.

From automotive engineering are automated transmission systems, such. As automated manual transmission (ASG) and parallel shift transmission (PSG) known, which include a single or a multi-shaft countershaft transmission. For gear ratio change or in a switching operation, a loose gear of the engaged gear or actual gear is separated from the transmission input shaft and a loose wheel of the gear to be engaged or target gear positively connected to the transmission input shaft in the transmission systems. Due to the jump in ratio, however, results in a difference in rotational speed between the transmission input shaft of the idler gear and the idler gear to be switched, whereby a positive connection without gear noise, such. B. the so-called ratchets, is not possible. For reasons of comfort, to synchronize the speed difference of the idler gear and the idler gear synchronization devices such. B. lock sync used.

The operation of the synchronization device can be in z. B. be divided five phases of the synchronization process.

In a first phase, a synchronizing is realized in which a synchronizer ring is pressed by means of the movement of a sliding sleeve, which is rotationally but axially displaceably connected to the loose shaft, via thrust pieces to the friction cone of a Losradkupplungskörpers. Due to the existing differential speed between the coupling body and the sliding sleeve of the synchronizer ring is rotated in the stop.

In the second phase, the actual synchronization is performed. In this case, the shift teeth of the shift sleeve is pressed with a synchronous force on their roof pitches to the roof slopes of the synchronizer ring. In this way, the idler wheel is accelerated or decelerated by the resulting friction torque. As long as a speed difference exists, the friction torque is always greater than the toothing moment, so that locks the synchronization device.

In a third phase, the synchronizer ring is rotated back so that the synchronizer is unlocked.

In a fourth phase, the coupling body is rotated, wherein the idler gear is rotated so that the shift sleeve can engage.

Finally, in a fifth phase, a positive connection between the teeth is produced by the switching toothing is fully meshed in the coupling body.

In order to enable optimum synchronization, on the one hand, a particularly soft Ansynchronisierungs with limited synchronizing force and reasonable speed is required to avoid too steep friction torque and a hard hitting the synchronizer ring against the stop. Otherwise, especially at low differential speeds switching noise caused by the synchronization and act on the output.

Furthermore, a sufficiently high synchronous force should be applied to achieve correspondingly short synchronous durations depending on the differential speed to be synchronized. An increased synchronous duration leads in particular in automated manual transmission systems to comfort disadvantages due to the extended interruption of traction. Furthermore, the synchronization device can be damaged by an increased energy input.

Furthermore, it is required that a sufficiently high synchronous force is applied in order to enable rapid unlocking and meshing. Otherwise, a differential speed can build up again, which can again lead to Einspurgeräuschen.

In order to meet these demands in automated transmission systems, it is essential to recognize the individual phases of the synchronization process, in particular the locking and unlocking of the synchronization device. In the case of the electromotive-operated transmission systems, the sensory detection of the transmission input rotational speed and the detection of the shift finger force are generally dispensed with for cost reasons. Thus, neither the beginning of the synchronization or the locking nor the end of the synchronization or the unlocking based on the transmission input speed in relation to the out the vehicle speed and the overall ratio resulting target input speed in the gear to be engaged or based on the switching force curve are determined by sensors.

From the vehicle technology, it is further known that therefore these phases is determined by the change of the state of motion of the gear actuator in the switching direction. For this purpose, the shift sleeve is moved at a certain speed depending on the desired synchronizing force and a limited Ansynchronisierungskraft to the synchronization. Provided that the kinetic energy stored in the state of motion in the actuator with the inertial mass related to the shift finger in the blocking state passes completely as potential energy into the stiffness reduced to the shift finger with the spring constant, a functional relationship can be specified. If the shift sleeve is delayed by a certain amount, a lock can be detected and the synchronizing force can be applied statically. Unlocking can be detected by an acceleration of the shift sleeve by a certain amount.

However, it has been shown that z. B. to avoid switching noise at low differential speeds very small synchronous forces are required. In this case, however, due to the losses of the internal circuit of the transmission only a slight acceleration of the shift sleeve after establishing the synchronization of the differential speed. Thus, the unlocking is detected delayed. In addition to a further increase in the switching time additionally results in the risk of Einspurgeräuschen, since in the time between unblocking and producing the positive connection between the shift sleeve and the gear teeth due to drag torque again can set a differential speed.

Accordingly, the present invention has the object to provide a method and a synchronization of the type mentioned, which optimize the switching sequence in an automated transmission with respect to the switching duration and possibly occurring switching noise.

This object is achieved by a method for controlling a synchronization device in a shift operation in an automated transmission, in which an expected synchronization time T _{Sync is determined} as a function of a respective differential speed Δω to be synchronized between a idler gear of the gear to be disengaged and a idler gear of the gear to be engaged, and wherein a synchronizing force required for synchronizing is increased after elapse of the determined synchronous _duration T _Sync . In this way, a control method according to the invention is proposed, in which a differential speed-dependent selection of the synchronizing force for increasing the degrees of freedom in the field of tension between the generation of switching noises on the one hand and the length of the synchronous _duration T _Sync on the other hand is realized. Furthermore, the synchronous duration T _Sync can be determined in advance on the basis of physical synchronous models and appropriate measures can be initiated in order to accelerate the meshing process or a possible error detection.

Next, it is provided that the sync period T _Sync determined after locking synchronization device and a timer is started, and that the synchronizing force F _Sync is increased linearly after the determined synchronous time T _sync. Thus, after the locking of the synchronizing device has been detected, the expected synchronous _duration T _sync can be determined immediately and a timer can be started, so that the start of the unlocking phase can be unambiguously determined after the synchronous _duration T _{sync has} elapsed. After unlocking the synchronization device, the synchronous force z. B. can be increased linearly to accelerate the expected unlocking and thus the entire synchronization process as a whole.

It is also conceivable that the unlocking phase is recognized by another criterion. Alternatively, with appropriate verification of the prediction can be detected directly to unlock. For example, in systems that provide a sensory determination of the input shaft speed or other variables, such as. B. the _traversed path of the shift sleeve or the shift rod, allow what conclusions on the actual synchronous _duration T _{Sync_tats} allow this direct recognition can be applied.

According to a development, it can be provided that in each case a ratio of the determined synchronous _duration T _Sync and an actual synchronous _duration T _{Sync_tats is} determined and used for the adaptation. In this way, the ratio for the adaptation of the gear actuator can be used with the aim of accurately maintaining the synchronous force over the entire life of the actuator. Thus, a parameter adaptation of the electric motors used and an adaptation of the Aktorwirkungsgrades done. In addition, there is the advantage that the comparison of the predicted and the actual synchronous _duration T _{Sync_tats can} also be used to detect hardware defects.

Below are calculation options for the differential speed to be synchronized Δω indicated. The differential speed Δω to be synchronized can be determined for example on the basis of the transmission output shaft rotational speed ω _{output shaft} and the known gear ratios of the actual gear i _{actual gear} and the target gear i _{target gear} . The transmission output shaft speed ω _{output shaft} can be measured or determined from the wheel speeds that are already determined for each ABS vehicle for the ABS function. For the calculation of the differential speed Δω to be synchronized, two cases can be distinguished, for example.

According to one embodiment of the present invention, the one possible case may relate to direct circuits between two gears. In this case, the differential rotational speed Δω can be determined directly from the transmission _output rotational speed ω _{output shaft} and the ratio of the gear to be _engaged i _{target gear} and from the ratio i _{Istgang of} the last fully synchronized gear (Istgang). This results in the following equation: Δω = | ω _{output shaft} · i _{target gear} - ω _{output shaft} · i _{actual gear} | = | ω _{output shaft} · (i _{target gear} - i _{actual gear} ) |.

ω_{Eingangswelle}:

Drehzahl der Eingangswelle

According to a next development, the second case may involve the engagement of a neutral gear. In this case, the differential speed Δω can be calculated according to the following equation: Δω = ω _{output shaft} · i _{target gear} ω _{input shaft} (t). With

ω _{input shaft} :

Speed of the input shaft

In this case, either the synchronization can be carried out with the input shaft completely thrown out and thus standing, in which case ω _{input shaft} = 0 applies. It is also possible that the input shaft is not yet complete, so that the coasting of the input shaft after laying out the gear with the speed ω _gear when laying the gear and the temperature-dependent loss torque in the neutral range M _loss (T _gear oil) depending on the transmission oil temperature and the mass inertia input shaft of the input shaft is determined according to the following equation:

This results in the differential rotational speed Δω to be synchronized from the transmission output shaft rotational speed ω _{output shaft} and the ratio of the gear to be _engaged i _{target gear} Δω = ω _{output shaft} · i _{target gear} - ω (t).

By calculating the respective differential rotational speed Δω to be synchronized, the setpoint synchronous force F _Sync for each gear can now be determined as a boundary condition for the expected synchronous duration T _Sync for each accelerator pedal position which indicates the driver's expectation with respect to the shift duration and the calculated relative differential rotational speed Δω. The relative differential speed Δω results here as the current differential speed, based on the maximum differential speed for the gear jump.

In this way maps can be created for each circuit, wherein z. B. a normal map for a comfort-oriented circuit and a sporting map for sporting circuits are given. The normal characteristic field is optimized by a linear dependence on the relative differential rotational speed Δω to as constant a synchronous duration T _Sync as possible. Small values between 5 and 25% relative differential speed Δω avoid loss of comfort due to the effect of the synchronous torque M _Sync on the output and possibly resulting interfering synchronous noises. The renewed increase below 5% relative differential speed Δω guarantees a speedy and safe engagement of a gear when the vehicle is stationary.

By contrast, in the case of a sports map, higher total synchronous forces and lower reductions over the relative differential rotational speed Δω may preferably be designed for minimum synchronous times T _Sync .

A further aspect of the present invention provides that for determining and predicting the expected synchronous duration T _Sync, the following physical relationship between the differential rotational speed Δω to be synchronized and the synchronous duration T _Sync can be used: J _red ω _{input shaft} (t) = M _Sync (t) ± M _loss (T _{transmission oil} ).

Here, the two terms are added on the right side when an upshift is performed, since the friction and loss moments have a delay effect on the idler gear. The two terms on the right side of the equation shown above are subtracted when there is a downshift. Under the legitimate assumption that the synchronous torque M _Sync is constant over time, the idleness reduced to the idler shaft J _red of the idler gears and shafts to be accelerated depending on the gearbox configuration depending on the gear configuration results in the expected sync duration T _Sync by the following Equation:

The fact that the transmission oil can usually warm up quickly during operation, it is possible that relatively small loss moments M _loss can be neglected in the warm operating state of the transmission system of about 2 Nm. The synchronous _torque M _Sync results from the synchronous force F _sync and the synchronization parameters, such. B. the cone angle α, the mean radius d, the friction surface number j and the coefficient of friction μ. Thus, the following equation results for determining the synchronous _torque M _Sync :

This results in the synchronous _duration T _Sync approximately by the following equation:

With k or k 'several physical variables are combined depending on the gear. These physical quantities can be stored or determined in a control unit, so that they can be retrieved in the simplest way for determining the respectively expected synchronous _duration T _Sync . K 'is the reciprocal of k.

Accordingly, can be determined by the above-mentioned context in the inventive method, the expected synchronous _duration T _sync as a function of each to be synchronized differential speed ω _{input shaft} and the synchronous force F _sync .

Accordingly, a method for the prediction of the expected sync _duration T _sync of z. B. Reibsynchronisiereinrichtungen, such as a lock synchronization described above or the like, proposed by means of the estimated synchronous force in automated countershaft gears and a method for differential speed-dependent determination of the synchronous force with the aim of avoiding comfort disadvantages by noise while ensuring a limited synchronization time.

Alternatively, it can also be provided for the prediction of the synchronous _duration T _sync that the acquisition of the transmission input rotational speed is effected by a suitable sensor system. As a result, the end of the synchronizing process, ie the unlocking, can likewise be determined exactly on the basis of the measured transmission input and output rotational speeds. The detection of absolute positions and switching forces on the shift fingers can also be done by sensors. As a result, the end of the synchronizing process can be detected on the basis of the receding switching force. In addition, the switching force can be precisely controlled.

The object underlying the invention is also achieved by a transmission actuator with a synchronization device for synchronizing a differential speed during a shift in an automated transmission in which the synchronization device is coupled to a transmission control unit, with an expected synchronous _duration T _sync in dependence on each one synchronizing differential speed .DELTA..omega. between a loose wheel of the gear to be interpreted and a loose wheel of the gear to be engaged can be determined, wherein a synchronous force F _sync required for synchronization is increased after the determined synchronous _duration T _{sync has} elapsed.

In this way, with the transmission actuator according to the invention during synchronization z. B. the unlocking can be detected in order to then control the synchronizing force accordingly to accelerate the meshing and improve the shift duration and the shift quality as a whole. The gear actuator according to the invention preferably serves with the synchronization device for carrying out the proposed method.

Claims (9)

Method for controlling a synchronization device in a shift operation in an automated transmission, wherein an expected synchronous duration (T _sync ) is determined as a function of a respectively to be synchronized differential speed (Δω) between a loose wheel of the gear to be interpreted and a loose wheel of the gear to be engaged, and that synchronizing force (F _Sync ) required for synchronization is changed after the determined synchronizing duration (T _Sync ) has elapsed, characterized in that the synchronous duration (T _Sync ) is determined after a locking of the synchronizing device and a timer is started, and that the synchronizing force (F _Sync ) is increased linearly after expiration of the determined synchronous duration (T _Sync ). A method according to claim 1, characterized in that in each case a ratio of a determined synchronous _duration (T _sync ) and an actual synchronous _duration (T _{Sync_tats} ) is determined and used for adaptation. Method according to one of the preceding claims, characterized in that the differential speed (Δω) in a direct circuit between the courses of the Transmission output speed ω _{output shaft} and the translation i _target gear of the gear to be _engaged and the ratio i _{Istgang is calculated} according to the following equation: Δω = | ω _{output shaft} · i _{target gear} - ω _{output shaft} · i _{actual gear} | = | ω _{output shaft} · (i _{target gear} - i _{actual gear} ) Method according to one of the preceding claims, characterized in that the differential rotational speed (Δω) is calculated during a shift from neutral according to the following equation: Δω = ω _{output shaft} · i _{target gear} - ω _{input shaft} (t) with ω _{input shaft} : speed of the input shaft A method according to claim 4, characterized in that the rotational speed of the transmission _input shaft (ω _{input shaft} (t)) is calculated according to the following equation:

with J _{input shaft} : mass inertia of the transmission _input shaft; T _{transmission oil} : transmission oil temperature; M _loss : temperature-dependent loss torque; ω _Gear : Speed when laying the gear. Method according to one of the preceding claims, characterized in that the expected synchronous _duration (T _sync ) is determined according to the following equation:

A method according to claim 6, characterized in that the synchronous torque (M _Sync ) after neglecting the loss torque (M _loss ) is determined according to the following equation:

A method according to claim 7, characterized in that the synchronous duration (T _sync ) is determined according to the following equation:

Transmission actuator with a synchronization device for synchronizing a differential speed in a shift in an automated transmission, wherein the synchronization device is coupled to a transmission control unit, with an expected synchronous duration (T _sync ) in response to each synchronized differential speed (Δω) between a loose wheel of auszustegenden Ganges and a loose wheel of the gear to be engaged is determined, wherein a synchronizing force required for synchronizing synchronous force (F _sync ) after the determined synchronous duration (T _sync ) is changed, characterized in that the synchronous duration (T _sync ) determined after a lock of the synchronization device and a Timing is started, and that the synchronous force (F _sync ) is increased linearly after the elapsed _{sync duration} (T _sync ).