EP2773888A1

EP2773888A1 - Process for synchronising a synchronisable transmission, a transmission controller and a synchronisable transmission

Info

Publication number: EP2773888A1
Application number: EP12783559.3A
Authority: EP
Inventors: Gergeley BOKA; Balazs Trencseni; Huba Nemeth
Original assignee: Knorr Bremse Systeme fuer Nutzfahrzeuge GmbH
Current assignee: Knorr Bremse Systeme fuer Nutzfahrzeuge GmbH
Priority date: 2011-11-03
Filing date: 2012-10-30
Publication date: 2014-09-10
Also published as: DE102011117586A1; WO2013064479A1

Abstract

The present invention relates to a process for synchronising a synchronisable transmission (44), comprising the determination of a first variable x that can be described in terms of a function f of the rotational speed difference Δη between a gearwheel (17, 18, 19, 20) and an associated locking element (22, 23) of the transmission (44), and the determination of a second variable y that can be described in terms of a function g of a synchronising torque M, and the rotationally fixed coupling of the gear wheel (17, 18, 19, 20) to the associated locking element (22, 23), taking account of the first variable, x, and the second variable, y. The present invention further relates to a transmission controller for controlling a synchronisable transmission and a synchronisable transmission.

Description

Method for synchronizing a synchronisable transmission, transmission control and synchronisable transmission

The present invention relates to a method for synchronizing a synchronizable transmission.

The present invention further relates to a synchronisable transmission and a transmission control for controlling a synchronizable transmission. In order to vary the speed of a vehicle in wide ranges, the use of gearboxes is known. The gears can provide multiple gears, each with a specific gear ratio. The ratio determines the speed ratio between an input shaft of the transmission and an output shaft of the transmission. The input shaft of the transmission may, for example, be coupled to a drive motor of the vehicle, while the output shaft of the transmission may be coupled to a drive shaft of the vehicle. A force flow from the input shaft of the transmission to the output shaft of the transmission can be produced, for example, by means of gear wheels which can be coupled in a rotationally fixed manner to the input shaft of the transmission or the output shaft of the transmission and which can be designed as toothed wheels of different sizes. For switching the transmission, that is to say for changing gears, the power flow from the input shaft of the transmission to the output shaft of the transmission can first be interrupted by releasing a hitherto rotationally fixed coupling of a gear wheel with a transmission shaft, for example the input shaft, the output shaft or a countershaft become. Subsequently, another gear can be rotatably coupled with one of the transmission shafts. This allows providing a different translation. To the non-rotatable coupling wear as little as possible To design, an at least approximate synchronization of the different speeds, for reducing the speed difference between the gear and the gear shaft is advantageous. Only after the synchronization, that is, an adjustment of the different speeds of the gear wheel and the gear shaft to an approximately common value, a low-wear rotationally fixed coupling between the gear and the gear shaft is possible. The rotationally fixed coupling can be done for example by the telescoping of a toothing as part of a locking member. From WO 2004/070232 A1 and WO 2005/003601 A1 respectively manual transmission are known, which allow the rotationally fixed coupling between the gear wheel and gear shaft, when the speed difference between the two parts to be coupled is smaller than a predetermined threshold. If the speeds of the gear wheel and the gear shaft are identical, this may cause the locking member initially can not engage because the associated teeth on the gear wheel and the gear shaft with the front sides of their teeth in contact. The closing of the locking member and thus the insertion of the new gear is then jerky at an incipient power flow between the input and the output shaft of the transmission. The onset of force moves the faces of the teeth against the frictional forces past each other until the teeth engage in the associated tooth gaps on the other component. Depending on the shape of the teeth and the size of the force flow to be transmitted, there may be a skip of gaps between individual teeth, in which the teeth of the locking member and the gear wheel drag or jump along with considerable wear on each other. In this case, the incipient force flow interferes with the synchronization between the gear wheel and the transmission shaft before closing the toothing between the locking member and the gear wheel by changing the speed difference between the gear wheel and the gear shaft. The switching process can therefore be accompanied by a noticeable jerk. The present invention has for its object to solve this problem and to enable the most comfortable switching operation. This object is solved by the features of the independent claims.

Advantageous embodiments and modifications of the invention will become apparent from the dependent claims. The invention consists of a method for synchronizing a synchronisable transmission comprising determining a first variable x, which can be represented as a function f of a rotational speed difference Δη between a gear wheel and an associated locking member of the transmission, and determining a second variable y, which can be represented as a function g of a synchronizing torque M, and the rotationally fixed coupling of the gear wheel with the associated locking member, taking into account the first size x and the second size y. Synchronization can be understood to mean the reduction of a speed difference, including the subsequent non-rotatable coupling of the synchronized parts. By taking into account the first size x and the second size y, a more accurate determination of operating states of the synchronizable transmission is possible in which a rotationally fixed coupling of the gear wheel with the associated locking member is easily possible. The first variable x can be represented as a function f of the rotational speed difference Δη, for example, if x = f (An). The second variable y can be represented, for example, as a function g of the synchronizing torque M, if y = g (M). In particular, the first variable x may correspond, for example, to the rotational speed difference An and the second variable y may correspond to the synchronizing torque M. The locking member may be formed, for example, as a shift sleeve. The shift sleeve can be arranged rotationally fixed and axially displaceable on the transmission shaft of the transmission. The method can be carried out, for example, by a control unit of the synchronisable transmission, which determines, for example, the variables x and y from values measured by sensors and controls or regulates the transmission based on the determined quantities. The determination of the variables x and y without specially provided sensors is also possible. Taking into account the first variable x and the second variable y during the rotationally fixed coupling, it is understood, in particular, that both the first variable x and the second variable y must fulfill conditions which may be independent of one another. For example, it can be provided that the first variable x is smaller than a barrier Xi and that the second variable y lies between a lower barrier yi and an upper barrier y ₂ . In this way, an improved characterization of the operating state can take place, which can take into account not only the speed difference or a variable derived therefrom but also another size.

It can be provided that the gear wheel and the associated locking member are rotatably coupled when a dependent of the first size x and the second size y current operating state S of the gear wheel and the associated locking member in a set D of predeterminable synchronized operating conditions of the gear wheel and the associated locking member is located. The predeterminable synchronized operating conditions may be, for example, in particular those operating states of the gear wheel and the associated locking member in which the rotationally fixed coupling of the gear wheel with the associated locking member wear and / or is possible without jerk. For example, the quantity D may have been experimentally determined beforehand or created by calculations and stored in a control unit carrying out the method. Furthermore, it can be provided that the set D is not in a form D (x, y) = {(x, y) | (di <x V di <x) Λ (x <d ₂ V x <d ₂ ) with di <d ₂ } can be represented if x the speed difference Δη and y are the synchronizing torque M. The indicated shape in which the quantity D is not representable denotes a surface bounded by two lines parallel to the y-axis. The symbol "Λ" stands for a logical AND. For example, the set D may be in one of the simplified forms D (x, y) = {(x, y) | di <x <d ₂ ) with di <d ₂ } and / or D (x, y) = D (x) can be specified. In other words, this may mean that the quantity D can not be given in a form dependent only on the rotational speed difference Δη, wherein no conditions are to be met with respect to the variable y. Usefully, it can be provided that a further variable x 'between a further gear wheel and an associated further locking member of the transmission is determined that for synchronizing the transmission, the further gear wheel and the further locking member are rotatably coupled, that a time t-ι is determined Starting from the current operating state S of the gear wheel and the associated locking member to achieve the amount D of synchronized operating conditions is required that a second time t _{2 is} determined, which is used to transfer the further gear wheel and the further locking member from a further operating state S ' the further gear wheel and the further locking member is required in a further amount D 'of synchronized operating conditions of the other gear wheel and the further locking member, and that the second size y is set to a value other than zero, if t-ι> t ₂ , "Different from zero" means that the synchronization is initiated, for example, a synchronizing torque M is generated as a second variable y. This allows a reduction in the time required for synchronization of the transmission, since synchronization of the gear wheel with the associated locking member already begins, while the synchronization of the other gear wheel with the associated further locking member, which is completed with a coupling of the two parts, not yet fully connected is. The further variable x 'may, for example, denote a further rotational speed difference Δη' or a spatial distance between transmission parts to be coupled. The conclusion of the synchronization can be completed for example by falling below a predetermined speed difference threshold or with the insertion or coupling of the synchronized parts, that is, with the rotationally fixed coupling. The synchronization referred to in connection with the further size x 'or the further amount D' so either a synchronization of the speed or a coupling / insertion. Interdependent, that is mutually influencing, Synchronizations thus occur at least partially simultaneously, so that the total time required for the complete synchronization of the transmission can be reduced. The further amount D 'of the synchronized operating states of the further gear wheel and of the further blocking member can be defined, for example, analogously to the quantity D of the synchronized operating states of the gear wheel and of the blocking member and / or can be determined experimentally. The periods t- ₁ and t ₂ can be predetermined experimentally, for example, depending on the respective operating states S and S ', and stored in a control unit of the transmission. Alternatively, a dynamic estimation of the time periods t- ₁ and t _{2 is} possible, in which estimated time curves t- ₁ and t _{2 are} estimated from prospective control curves of the two operating states S and S '. A mixture of both possibilities is also possible.

In this context, it may be provided that the second variable y is limited in terms of value as long as a distance Δ of the further operating state S 'of the further gear wheel and of the further blocking member to the quantity D' of synchronized operating states of the further gear wheel and of the further blocking member is greater is a predeterminable threshold AS '. The absolute limitation of the second variable y facilitates the synchronization of the first variable. In this way, for example, the control / regulation for synchronizing the further gear wheel with the associated further locking member can be carried out independently of the synchronization of the gear wheel with the associated locking member. In particular, it can be provided that the second variable y is limited in magnitude to a value which does not increase the distance Δ and / or a first derivative of the distance Δ. The distance Δ can be determined, for example, as a Euclidean norm or as any other standard which appears suitable to a person skilled in the art and defines a distance.

It is also possible for the current operating state S to be brought into a synchronized operating state encompassed by the quantity D by a control or regulation of the second variable y. Furthermore, it can be provided that the control or regulation of the current operating state S by a time-varying feedback C (t) is realized. A time-varying feedback C can allow rapid and at the same time secure control or regulation for transferring the transmission from its current operating state S into a synchronized operating state. The time-varying feedback can be predefined, for example, as negative feedback or negative feedback in the form C (t) = F (D, S [x (t), y (t)]), where any function that appears appropriate to the person skilled in the art is suitable Function can be used. For example, a function representing a sliding mode control.

Alternatively it can be provided that the control or regulation of the current operating state S is realized as a finite automaton. In this way, the transfer of the transmission can be shown in a synchronized operating state in a predetermined manner. For example, unstable control behavior due to non-linear system properties can be avoided in this way. The to a set operating state S of the gear wheel and the associated locking member associated and to be set second size y, for example, the synchronizing torque M, for example, can be predetermined experimentally.

Usefully, it can also be provided that, in determining the quantity D of predeterminable synchronized operating states of the gear wheel and the associated blocking member, at least one further variable, which is of the first size x and the second size, is taken into account in addition to the first size x and the second size y y is independent. The further variable may be, for example, a vehicle speed. The further size may be a direct or indirect th effect on the synchronization process of the gear wheel and the associated locking member have. For example, a larger vehicle speed mean higher speed differences between the gear to be synchronized parts that need to be dismantled.

Advantageously, it can be provided that the amount D of predeterminable synchronized operating states of the gear wheel and the associated locking member for different pairs of gear wheels and locking members is determined independently. Different gear wheels provide different ratios. Therefore, the determination of the quantity D for a first pair of transmission parts to be synchronized may be different from another quantity D for a second pair of transmission parts to be synchronized, which is different from the first pair of transmission parts. A pair of gear parts to be synchronized consists of a gear wheel and an associated blocking member.

The invention further consists of a transmission control for controlling a synchronisable transmission comprising an electronic control device, which is set up to carry out one of the methods described above. In particular, the control unit can be set up to carry out the individual steps of the methods described above.

The invention further consists of a synchronizable transmission with such a transmission control.

In this way, the advantages and peculiarities of the method described can also be implemented in the context of a device.

The advantages and particularities of the method described in connection with the dependent claims can be applied in the same way in the context of Transmission control to control a synchronizable transmission can be implemented.

The device and the method are described below by means of exemplary embodiments.

A schematic representation of a transmission with countershaft; a gear wheel and an associated locking member in a first position;

Figure 3 shows a gear wheel and an associated locking member in a second position;

Figure 4 shows a gear wheel and an associated locking member in a third position;

Figure 5 shows a gear wheel and an associated locking member in a first position; Figure 6 is a gear wheel and an associated locking member in a second position;

Figure 7 shows a gear wheel and an associated locking member in a third position; FIG. 8 shows a first set of operating states D (x, y) of a synchronisable transmission;

FIG. 9 shows a second set of operating states D (x, y) of a synchronizable transmission; and Figure 10 shows a time profile of the operating states of a synchronizable transmission.

In the following drawings, like reference characters designate like or similar parts.

Figure 1 shows a schematic representation of a transmission with countershaft. The illustrated transmission 44 comprises an input shaft 1, an output shaft 2 and a countershaft 3, which may be arranged offset to the input shaft 1 and the output shaft 2. On the countershaft 3, a first gear 4, a second gear 5, a third gear 6, a fourth gear 7 and a fifth gear 8 are provided which are each rotatably connected to the countershaft 3. On the input shaft 1, a first Loserad 9 is provided. The loose wheel 9 can be coupled by means of a first locking member 21 via a first gear 15 rotatably connected to the input shaft 1. The input shaft 1 may further be rotatably coupled via the first locking member 21 and a second gear 16 with a second loose wheel 10. On the second gear wheel 16 opposite side of the second Loserades 10, a third gear 17 is arranged which, together with a second locking member 22, the second Loserad 10 rotatably coupled to the output shaft 2 can. On the output shaft 2, a third Loserad 1 1, a fourth Loserad 12 and a fifth Loserad 13 are further arranged. The third Loserad 1 1 is rotatably coupled to the output shaft 2 via a fourth gear 18 and the second locking member 22. The fourth Loserad 12 is rotatably coupled to the output shaft 2 via a fifth gear 19 and a third locking member 23. The fifth Loserad 13 is also rotatably coupled to the output shaft 2 via a sixth gear 20 and the third locking member 23. A toothing of the first gear 4 is in constant engagement with a toothing of the first Loserades 9. A toothing of the second gear 5 is in constant engagement with a toothing of the second Loserades 10. Furthermore, a toothing of the third gear 6 are in constant engagement with a toothing of the third Loserades 1 1 and a toothing of the fourth A toothing of the fifth gear 8 is in constant engagement with a toothing of an intermediate gear 14, wherein the toothing of the intermediate gear 14 in turn is in constant engagement with a toothing of the fifth Loserades 13.

With the illustrated transmission 44, six different forward gears and two reverse gears can be realized, wherein the reversal of the direction of rotation of the output shaft 2 via the intermediate gear 14 is realized. The illustrated gear 44 is synchronized on the input side via synchronizer rings 24 between the first locking member 21 and the first gear 15 and between the first locking member 21 and the second gear 16. On the output side, the illustrated gear 44 is synchronized via a brake device 25, which serves as a common synchronizer for the second Loserad 10, the third Loserad 1 1, the fourth Loserad 12 and the fifth Loserad 13 with respect to the output shaft 2. The first locking member 21 may be controllable via a first switching device 26 by an electronic control unit 36. The second blocking member 22 can be actuated by the electronic control unit 36 via a second switching device 27. Furthermore, the third blocking member 23 can be actuated by the electronic control unit 36 via a third switching device 28. The switching state of the first blocking member 21 can be monitored by the electronic control unit 36 via a first sensor device 29. Likewise, a second sensor device 30 monitor the switching position of the second locking member 22 while a third sensor device 31 can monitor the switching state of the third locking member 23. The measured values or data determined by the first sensor device 29, the second sensor device 30 and the third sensor device 31 can be transmitted to the electronic control unit 36 for evaluation. Depending on requirements, a fourth sensor device 32 may further be provided for detecting a rotational speed of the input shaft 1 and be coupled to the electronic control unit 36. Exemplarily dargstellt is still a fifth sensor device 33, to determine a speed of the third Loserades 1 first Because of the solid Gearing between the third Loserad 1 1 and the third gear 6 can be determined via the fifth sensor means 33 and the rotational speed of the countershaft 3. Finally, a sixth sensor device 34 serves to determine a rotational speed of the output shaft 2. Other sensor devices not explicitly shown for detecting different rotational speeds of individual parts of the transmission 44 can be provided as required. Additional sensors, also not shown, which may serve, for example, the detection of the spatial position of individual parts of the transmission or the distance between individual parts of the transmission, may also be provided as needed. The measured values or data determined by all the sensor devices 29, 30, 31, 32, 33, 34 can be transmitted to the electronic control unit 36. The control unit 36 may be coupled via a connection 35 to a vehicle bus. The control unit 36 can furthermore determine an optimal gear and insert it automatically on the basis of data transmitted via the sensor devices 29, 30, 31, 32, 33 and 34 and via the connection 35. Manual gear selection may also be possible. The first sensor device 29, the second sensor device 30 and the third sensor device 31 may include, for example, sensors for determining the position of the respective locking members. In the event of a defect, that is, when blocking a blocking member, it can be provided that the control unit can select the most suitable from the remaining selectable gears.

The first locking member 21 may, for example, have three different switching positions. In a first switching position of the first locking member 21, the input shaft 1 can be decoupled both from the first Loserad 9 and from the second Loserad 10. In a second switching position of the first locking member 21, the input shaft 1 rotatably coupled to the first Loserad 9, so that the second Loserad 10, the third Loserad 1 1, the fourth Loserad 12 and the fifth Loserad 13 on the countershaft 3 with the on it rotatably arranged gears 5, 6, 7 and 8 are driven. In a third switching position of the first locking member 21, which is also shown in Figure 1, the input shaft 1 is rotatably coupled to the second Loserad 10. Also in this switching position Other loose wheels 4, 6, 7 and 8 are driven via the countershaft 3. The first switching position, which corresponds to a neutral position, can also be omitted as needed, so that only two different switching positions of the first locking member 21 are provided. By selecting the respective switching positions of the second locking member 22 and the third locking member 23, which in turn each have three different switching positions, the ratio of the transmission 44 may be selected in a conventional manner. Shown is a first switching position of the second locking member 22, in which both the second Loserad 10 and the third Loserad 1 1 with respect to the output shaft 2 is freely rotatable. Shown further is the third locking member 23 in a switching position in which the fourth Loserad 12 is rotatably coupled to the output shaft 2 while the fifth Loserad 13 is freely rotatable relative to the output shaft 2. The transmission 44 shown in FIG. 1 therefore conducts a power flow originating from the input shaft 1, first via the second loose wheel 10 and the second gear 5 to the countershaft 3 and from there via the fourth gear 7 and the fourth loose wheel 12 to the output shaft 2.

In order to allow a smooth, comfortable and smooth shifting and to reduce the load change when changing gears, after an initial interruption of the power flow, a speed difference between non-rotatably to be coupled gear parts, such as one of the idler gears 9, 10, 1 1, 12, 13 and one of the blocking members 21, 22, 23, usually initially reduced during a synchronization phase, before the non-rotatable coupling actually takes place.

For example, the synchronization via synchronizing rings 24 take place, as shown in connection with the first Loserad 9, the second Loserad 10 and the first locking member 21 in Figure 1. The first locking member 21 is slidably disposed in the axial direction rotatably on the input shaft 1. The first locking member 21 may be formed, for example in the form of a conventional shift sleeve, which may have a toothing on its outer side or its inner side. For rotationally fixed coupling of the first locking member 21, this can by displacement in the axial direction in engagement with an associated inner toothing or an associated external toothing of the first gear wheel 15 or the second gear wheel 16 are brought. The first contact between the respective gear wheel 15, 16 and the first locking member 21 takes place via the synchronizer ring 24, which degrades by means of friction any existing difference in speed between the teeth of the gear wheel 15, 16 and the toothing of the first locking member 21. Only after the reduction of the speed difference, the actual rotationally fixed coupling takes place.

The braking device 25 controlled by the electronic control unit 36 represents a common synchronization device for the second locking member 22 and the third locking member 23. The braking device 25 can assist in synchronization, for example during shifting operations, in which the third gear 17, the fourth gear 18, the fifth Gang wheel 19 and the sixth gear 20 are involved. By braking the countershaft 3, a speed difference between the second Loserad 10, the third Loserad 1 1, the fourth Loserad 12 and the fifth Loserad 13 and the output shaft 2 are reduced. The synchronization of the first Loserades 9 and the second Loserades 10 relative to the input shaft 1 via the synchronizer rings 24 may be independent of a synchronization of the second Loserades 10 of the third Loserades 1 1, the fourth Loserades 12 and the fifth Loserades 13 with respect to the output shaft 2, the takes place by means of the braking device 25. However, the actuation of the braking device 25 also has an effect on the synchronization of the first locking member 21 with the first Loserad 9 or the second Loserad 10. The synchronization via the braking device 25 may be characterized by an operating state S (x, y), wherein a first variable x, for example, a rotational speed difference Δη between the respective gear 17, 18, 19, 20 and the respective associated locking member 22, 23 be can, and a second size y, which may be a synchronizing torque M, for example, can be used. A set D (x, y) of synchronized operating conditions may be defined in which the controller may attempt to non-rotatably couple the previously synchronized transmission parts. The method of synchronization will be described in more detail in connection with the following figures.

The application of the described method is not limited to the transmission 44 shown in FIG. Rather, the method described can be used together with any desired transmission with at least one common synchronization device, the synchronization of a plurality of clutches, that is to say the adaptation of the movement of mutually movable parts, in at least some of the possible gearshifts, ensured by the common synchronization device can be. In particular, the number of input shafts does not matter and can be chosen variably. From the prior art it is known to set the synchronized operating state over a speed difference range so that the fluctuations in the drive train after engagement of the gear wheel and the occurring switching noise possible lent remain low. The speed difference range may be set for this purpose so that the skipping of gaps between individual teeth, in which the teeth of the locking member and the gear wheel with considerable wear on each other along loops or jump does not occur, and that the associated teeth on the gear wheel and the locking member If possible, do not stay in permanent contact with the front of their teeth. However, the sole consideration of the speed difference can not guarantee a satisfactory shift quality in each case. The method described here makes it possible to realize significant improvements in shift quality by means of a refined determination of the synchronized operating state.

The transmission 44 described in FIG. 1 comprises a common synchronization device in the form of the transmission brake 25 and a synchronization device independent of it in the form of the synchronizer rings 24. In the event of a change between two different speeds, two independent synchronizers may be required. A synchronization using the gear brake 25 and a further synchronization using the synchronizer rings 24. Das Actuating the transmission brake 25, however, can interfere with the synchronization by the synchronizer rings 24, since the transmission brake 25 via the first gear 4 and the second gear 5 also the second gear 9 and the third gear 10 influences flow. Therefore, the transmission brake 25 is usually only operated when the synchronization over the synchronizer rings 24 completed and the synchronized parts of the transmission 44, here the first gear 15 or the second gear 16 and the first locking member 21, are rotatably coupled. For the synchronization via the synchronizer rings 24, an operating state S 'of the further gear wheel and the associated further blocking element can be determined in part analogously to the synchronization via the transmission brake 25. The further gear wheel can then be, for example, the first gear wheel 15 or the second gear wheel 16. The further blocking member is then the second locking member 22. Also can be determined analogously to the amount D a set D 'of the synchronized operating conditions of the other gear wheel and the further locking member, wherein synchronized in connection with the set D' also coupled or inserted operating states can be understood, in particular if the further size x ', a spatial distance of the gear parts to be coupled designates. Since synchronization by means of the synchronizer rings 24 also influences the synchronization by means of the transmission brake 25, an exchange of S and S 'as well as of D and D' may also be possible. By at least partially simultaneous synchronization, that is, by the operation of the transmission brake 25 while the gear and the locking member are not rotatably coupled, the synchronization of the transmission can be accelerated if the synchronization of the gear and the locking member is not adversely affected. This can be ensured for example by a sufficiently low actuation of the transmission brake 25, that is, by a sufficiently small synchronizing torque M. Even a slight actuation of the transmission brake 25 shortens the remaining time for synchronization of the gear wheel and the associated locking member. Figure 2 shows a gear wheel and an associated locking member in a first position. Shown are the fourth gear 18 and the second locking member 22 and teeth 37 of the teeth to be engaged. In this case, the teeth 37 of the fourth gear wheel 18 and the second locking member 22 are each in holes 53 of the opposite parts come to rest. The laterally arranged arrow symbolizes the relative direction of rotation, that is to say the rotational speed difference Δη of the fourth gear wheel 18 relative to the second blocking member 22.

Figure 3 shows a gear wheel and an associated locking member in a second position. The parts already known from FIG. 1 approach one another in a closing direction 39 until the teeth 37 finally intermesh after the existing rotational speed difference Δη has been reduced. On the second locking member 22 shown in Figure 3 acts during the movement in the closing direction 39, a first torque 40, which is generated by the braking device 25. Furthermore, a second torque 41, which comprises all the torques not caused by the brake device 25, for example, a torque caused by friction losses within the transmission 44, and a third torque 42, which at the end faces of the teeth 37 due to the friction by the contact force in the Closing direction 39 is generated. The third torque 42 acts against the relative rotational speed difference Δη of the second locking member 22 and the fourth gear wheel 18. When the relative rotational speed difference Δη is reduced by the third torque 42 before the teeth 37 reach into the holes 53, so that the teeth are engaged is, a permanent tooth-on-tooth position may arise, which can lead to a sudden displacement of the teeth against each other when inserting a transmitted power flow. Alternatively, a restart of the synchronization process is possible. The first torque 40 exerted by the braking device 25 should therefore be determined so that a tooth-on-tooth position can not occur when the speed difference Δη disappears. Figure 4 shows a gear wheel and an associated locking member in a third position. In Figure 4, the final state of a successful synchronization is shown, in which the toothing of the second locking member 22 engages in the associated toothing of the fourth gear wheel 18 and a power flow can be transmitted.

Figures 5, 6 and 7 also show a respective gear wheel and associated locking member in a first, a second and a third position. The illustrated in Figures 5, 6 and 7 fourth gear 18 and the illustrated second locking member 22 differ from the one shown in Figures 1, 2, 3 and 4 th gear wheels and locking members in that instead of teeth 37 further teeth 38 with a different profiling are shown. Due to the profile of the other teeth 38 is formed as a counter force to the actuating force in the closing direction 29, a force 43, which can lead to an undesirable skipping of the holes 53 under increased fatigue at the teeth 38.

FIG. 8 shows a first set of operating states D (x, y) of a synchronisable transmission. Illustrated on the x-axis, for example, a speed difference Δη may be the first quantity x. Illustrated on the y-axis, for example, a synchronizing torque M may be a second quantity y. A set D 45 is limited by a lower threshold di 47 and an upper threshold d ₂ 48. The lower threshold di 47 and the upper threshold d ₂ 48 may accordingly denote allowable speed deviations between a locking member and the associated gear wheel. The amount D may denote the amount of operating states S (x, y) in which a transmission control of the synchronizable transmission stops a synchronization phase and engages the gear by the non-rotatable coupling of the gear wheel with the associated locking member. As has already been described in connection with FIGS. 2 to 6, the quantity D shown in FIG. 8 can include operating states S of the synchronisable transmission which do not lead to jolt-free or successful rotationally fixed coupling, for example, by the occurrence of a tooth-on-tooth position at vanishing speed difference Δη.

FIG. 9 shows a second set of operating states D (x, y) of a synchronizable transmission. In contrast to the first set of operating states known from FIG. 8, the second set D 45 of operating states shown in FIG. 9 is delimited by a peripheral edge 49, so that the second set D 45 of operating states D (x, y) does not function exclusively the first size x can be displayed. The edge 49, which limits the second set D 45 of operating states, can be defined, for example, by a function P (x, y), which describes the probability of successful engagement of the gear in an operating point S 46 of the synchronisable transmission. For example, engagement of a aisle can be considered unsuccessful if a tooth-on-tooth position or the skipping of a hole occurs. The probability of this can be described by P (x, y). Furthermore, a function T (x, y) can be used, which indicates the maximum of vibrations in the drive train of the vehicle after engaging the gear, wherein the vibrations can be caused in particular by torsional vibrations. The edge 49 of the second set D of operating conditions may then be given in the form, for example

D = {(x, y) | (P (x, y)> Pmin) Λ (T (x, y) <T _max )}, where P _min and T _{max represent} predeterminable values. The functions P (x, y) and T (x, y) can be determined experimentally or mathematically for a given transmission or a given drive train. The thus defined amount D then only includes the operating states of the transmission, in which a rotationally fixed coupling of the gear wheel and the associated locking member with a probability greater than P _{min is} successful and where additionally the vibration in the drive train remains smaller than T _max . The quantities D and / or D 'can be determined separately for all pairs of transmission parts to be synchronized, and different amounts D and / or D' can also be determined for different pairs of transmission parts to be synchronized. Furthermore, additional quantities, for example the vehicle speed, can be taken into account when determining the quantities. For example, a plurality of different quantities D can be provided for a gear wheel and an associated blocking member and stored in a memory of the electronic control unit 36. The electronic control unit 36 may select one of the stored amounts D of pending synchronization depending on the current operating state of the vehicle, for example the vehicle speed.

FIG. 10 shows a time profile of the operating states of a synchronisable transmission. Shown in FIG. 10 is the operating state of the synchronisable transmission starting from a starting point 50 at which a synchronization phase is initiated up to an end point 52 which may be in the quantity D 45 of operating states of a synchronisable operation in which the force flow through the Intermeshing of the toothing between a gear wheel and an associated locking member is made. Starting from the starting point 50, the second variable y is increased by the actuation of the braking device 25, which may be, for example, the synchronizing torque M, so that consequently the second variable y increases and at the same time the first variable x decreases, for example the rotational speed difference Δη between can represent the transmission parts to be synchronized. Accordingly, the operating state S of the synchronizable transmission travels along the curve 51 from the starting point 50 to the end point 52. The control or regulation of the second quantity y, for example of the torque M generated by the braking device 25 can take over the control unit of the transmission. The operating state S of the synchronisable transmission must be brought from the starting point 50 to a point within the amount D 45 of operating conditions in order to complete the synchronization of the transmission with a successful rotationally fixed coupling. The torque to be applied by the braking device can be determined, for example, by means of a time-varying feedback C. The feedback function C may, for example, in the form

C (t) = F (D, S [x (t), y (t)]). The function F can represent any feedback function familiar to the person skilled in the art, for example a function associated with the sliding mode control.

Alternatively or additionally, the control of the second quantity y can also take place according to the principle of a finite state machine, wherein the space spanned by the first variable x and the second size y first discretizes and, for example, by experiment or calculation, a value for the discretized range thus determined second variable y is determined, so that the approach to the amount D 45 of the synchronized operating states of the transmission, for example, takes place as quickly as possible. In order to stabilize and / or improve the control, both methods for determining the second variable y can also be suitably mixed with one another, wherein, for example, at periodic intervals the second variable y is determined in accordance with the finite state machine while there is a time-varying feedback between them is used to determine the second size y. The features of the invention disclosed in the foregoing description, in the drawings and in the claims may be essential to the realization of the invention both individually and in any combination. LIST OF REFERENCE NUMBERS

1 input shaft

2 output shaft

3 countershafts

4 first gear

5 second gear

6 third gear

7 fourth gear

8 fifth gear

9 first lottery

10 second lottery

1 1 third lottery

12 fourth lottery

13 fifth lottery

14 intermediate wheel

15 first gear wheel

16 second gear wheel

17 third gear wheel

18 fourth gear wheel

19 fifth gear wheel

20 sixth gear wheel

21 first locking member

22 second locking member

23 third locking member

24 synchronizer ring

25 braking device

26 first switching device

27 second switching device 28 third switching device

29 first sensor device

30 second sensor device

31 third sensor device

32 fourth sensor device

33 fifth sensor device

34 sixth sensor device

35 connection

36 electronic control unit

37 tooth

38 more teeth

39 closing direction

40 first torque

41 second torque

42 third torque

43 power

44 gearbox

45 amount D

46 operating point S

47 lower threshold di

48 upper threshold d ₂

49 edge

50 starting point

51 curve

52 end point

53 holes

Claims

4068_K claims

1 . Method for synchronizing a synchronisable transmission (44) comprising determining a first variable x, which can be represented as a function f of a rotational speed difference Δη between a gear wheel (17, 18, 19, 20) and an associated locking member (22, 23) of the transmission (44) determining a displayable as a function g of a synchronizing torque M second

Size y, and the rotationally fixed coupling of the gear wheel (17, 18, 19, 20) with the associated locking member (22, 23), taking into account the first size x and the second size y.

2. The method according to claim 1, characterized in that the gear wheel (17, 18, 19, 20) and the associated locking member (22, 23) are rotatably coupled when a dependent of the first size x and the second size y current operating state S of the gear wheel and the associated locking member in a set D of predeterminable synchronized operating states of the gear wheel (17, 18, 19, 20) and the associated locking member (22, 23).

3. The method according to claim 2, characterized in that the amount D is not in a mold

D (x, y) = {(x, y) | (di <x V di <x) Λ (x <d ₂ V x <d ₂ ) with di <d ₂ } can be represented if x the rotational speed difference Δη and y are the synchronizing torque M.

4. The method according to claim 2 or 3, characterized in that a further size x 'between a further gear wheel (15, 16) and an associated further locking member (21) of the transmission (44) is determined that for switching the transmission further Gear wheel (15, 16) and the further locking member (21) are rotatably coupled, that a time t-ι is determined, the starting from the current operating state S of the gear wheel (17, 18, 19, 20) and the associated locking member (22,

23) is required to achieve the amount D of synchronized operating states of the gear wheel (17, 18, 19, 20) and the associated locking member (22, 23), - that a second time t _{2 is} determined, which is used to transfer the other gear wheel ( 15, 16) and the further locking member (21) from an operating state S 'of the further gear wheel (15, 16) and the further locking member (21) in a set D' of synchronized operating conditions of the further gear wheel (15, 16) and the associated further blocking element (21) is required, and that the second quantity y is not set to a value other than zero if t- ₁ > t ₂ .

5. The method according to claim 4, characterized in that the second size y is limited in amount, as long as a distance of the operating state S 'of the further gear wheel (15, 16) and the associated further locking member (21) to the amount D' of synchronized operating conditions of the further gear wheel (15, 16) and the associated further locking member (21) is greater than a predetermined threshold Δ.

6. The method according to any one of claims 2 to 5, characterized in that the current operating state S is brought by a control or regulation of the second size y in a synchronized operating state encompassed by the set D.

7. The method according to claim 6, characterized in that the control or regulation of the current operating state S by a time-varying feedback C (t) is realized.

8. The method according to claim 6, characterized in that the control or regulation of the current operating state S is realized as a finite automaton.

9. The method according to any one of claims 2 to 8, characterized in that in determining the amount D of predeterminable synchronized operating states of the gear wheel (17, 18, 19, 20) and the associated locking member (22, 23) in addition to the first size x and the second size y is taken into account at least one further size, which is independent of the first size x and the second size y.

10. The method according to any one of claims 2 to 9, characterized in that the amount D of predeterminable synchronized operating states of the gear wheel (17, 18, 19, 20) and the associated locking member (22, 23) for different pairs of gear wheels (17, 18, 19, 20) and locking members (22, 23) is determined independently of each other.

1 1. Transmission controller for controlling a synchronizable transmission (44) comprising an electronic control unit (36) adapted to carry out a method according to any one of claims 1 to 10.

12. Synchronisierbares transmission (44) with a transmission control according to claim 1 1.