FR2799256A1 - METHOD FOR SYNCHRONIZING A MOTOR VEHICLE TRANSMISSION - Google Patents

Abstract

A method for performing switching operations in an automatic gearbox (24), having between an input axis (22) and an output axis (26) a synchronization device (64) and a torque transmission path ( 56) selectively activated or deactivated by the control of an actuator (40). To perform a synchronization operation, the following steps are carried out: a) the actuator (40) is placed in the synchronization start position, b) once the synchronization start position is reached, the actuator (40) is controlled. during a synchronization interval (tSYNC) so that the rotational speed of the input axis (22) varies in a predetermined manner towards a predetermined target final rotational speed (N2).

Description

The present invention relates to a method for

  perform switching operations in a video box

  automatic braids having at least one torque transmission path between an input axis and an output axis of the gearbox with a synchronization device, this

  torque transmission being activated or deactivated selectively-

  ment by controlling an actuator.

  In such a method described for example in document DE 197 09 417 AI, to execute the synchronization of a gearbox, that is to say essentially to avoid a jerk during a changeover, the speed is set of

  gearbox input shaft rotation at one speed

  corresponding tesse by an appropriate command of the motor unit, speed that this axis will have once the commutation carried out. For this it is necessary to execute control measures appropriate for the power unit. Although such a means makes it possible to maintain synchronization between the input shaft and the gearbox output shaft, this does not make it possible to avoid a jerk with certainty, for example when coupling d '' a pinion on the input or output axis

  of the gearbox to establish the transmission of

  ple by passing a gear ratio, during the acceleration or deceleration of this toothed pinion. To avoid this, it is for example known to put the actuator first

  synchronization start position and starting from this po-

  position, the actuator is controlled by monitoring its position

  from the point of view of the force it must provide. When we de-

  passes a certain limit position, it is assumed that the syn-

  internal timing in the gearbox, for example between a pinion and a shaft of the gearbox, has taken place and

  during another operation, we can then couple solidarity-

  this toothed pinion serving as a transmission element for

  torque and the corresponding axis of the gearbox.

  Due to the command executed during the synchronization phase proper, the problem with such a procedure is that the actuator does not have exact information of the instant synchronization state. This is particularly noticeable because the actuation position of the actuator from which begins

  actually the synchronization is not a significant quantity

  operating aunt, but may for example vary in

  depending on the age of the gearbox and / or the temperature

  cross out. In order to avoid switching jolts caused by too fast synchronization or the dead time being too long due to too slow synchronization, a compromise must be made between comfort and

  secondly the switching speed; however this compromise pre-

  has disadvantages in many situations of con-

  pick. The object of the present invention is to develop a method for executing switching operations in an automatic gearbox making it possible to execute in particular

  a high speed synchronization operation and

very comfortable.

  To this end, the invention provides a method

  characterized in that to execute an operation of syr.chroni-

  sation for at least one torque transmission path, the following steps are carried out:

  a) the actuator is put in the synchronization start position

  sation, b) as soon as the synchronization start position is reached, the actuator is controlled during a synchronization interval so that the speed of rotation of the input axis of the gearbox varies greatly.

  predetermined towards a final rotation speed of

predetermined sign.

  According to the present invention, thanks to the over-

  permanent monitoring of the speed of rotation of the input shaft of the gearbox there is permanent information on the intensity (induced by the control of

  actuator) of the force applied to the synchro-

  nisation for the execution of synchronization. The greater the force generated by the actuator, the greater the speed of rotation of the input shaft of the gearbox

  will change dramatically, and the rotation speed monitoring

  tion of the gearbox input axle allows

  indirectly monitor the force generated by the actuator.

  Thus, we know permanently the operating state-

  during a synchronization operation, and we avoid

  any deterioration in comfort and any inconvenient downtime.

  So that at the end of the synchronization phase it is possible to enter a torque transmission state, the method further comprises a step c) so that at the end of the synchronization interval, the torque transmission path going into a preparatory state for the transmission of

couple.

  For example, to move from a neutral position of

  the gearbox or from an earlier report, as fast-

  ment as possible in the synchronization phase, in the step

  a), the actuator is put in the synchronization start position.

  tion by an operation to regulate the actuating position.

  To have a synchronization phase without

  blow and fast in step b) a chronological evolution is predetermined for a set speed of rotation of the input axis of the gearbox, and the actuator is controlled in an operation for regulating the speed of the input axis of the gearbox so that during

  the synchronization time interval, a speed of ro-

  tation of the input axis of the gearbox, mainly following the predetermined chronological evolution of the setpoint rotation speed of the input axis (22)

of the gearbox.

  The characteristic that the setpoint speed, predetermined for the end of

  the synchronization time interval corresponds to the vi-

  Final set rotation speed of the input axis of the gearbox, makes it possible to minimize or eliminate the dead times produced during the execution of a switching operation. According to another characteristic of the invention, to optimize the comfort or the chronological execution of a

  switching operation, the chronological evolution is predetermined

  axis setpoint speed logic

  gearbox input depending on operating condition

is lying.

  For this, for example according to another characteristic

  of the invention, in step b), from more

  depending on the setpoint speed / time functions, depending on the operating state, a function is selected to predetermine the chronological evolution cde the speed of

  setpoint rotation of the gearbox input axis-

his.

  This operating state according to which in defi-

  nitive we decide how to proceed with the syn-

  chronization, can be defined at least taking into account one of the following parameters:

  * speed of rotation of the output axis of the gearbox

  braids, * travel speed, * driving mode: sporty / economical,

  * transmission ratio of the transmission path of

  ple to activate, * type of gear change: up / down

* temperature.

  A function according to which the speed of the input axis of the gearbox in the synchronization phase is modified, once selected in principle, makes it possible, advantageously or necessary, to adapt to the limit conditions provided for by the state instant operation. The

  function selected to predetermine the chrono-

  logic of the setpoint speed of the input axis of the gearbox is further adapted according to one of the following parameters: * synchronization time interval (tSyNc), * actual rotation speed of the gearbox input axis at the start of the synchronization interval, * travel speed,

  * speed of rotation of the output shaft of the gearbox

braids,

  * transmission ratio of the transmission path of

ple to activate.

  The synchronization interval which ultimately is the interval in which synchronization occurs according to the corresponding actuator command, is an essential influence quantity defining the preference

  given either to comfort or to the speed of switching.

  This is why it is also advantageous in the method of the invention for the synchronization time interval to be

o10 variable.

  It is for example possible to provide for selecting the synchronization time interval at least according to one of the following parameters:

  - nature of the gear change: my-

tee / descent,

  - driving mode: sporty / economical.

  In the method according to the invention, it is preferably provided that the starting synchronization position is an actuation position of the actuator which has an offset with respect to the actuation position for which

  actually starts synchronization.

  This means that, due to an improper

  possible regulatory decision in the execution of the stage

  a), the brutal action on the synchronization device

  son-in-law. In the same way, by predefining a certain speed of variation of the rotation speed of

  the input axis of the gearbox, even in a situation

  tion in which ultimately the actuator does not perceive

  still a reaction force, avoiding too strong an acceleration

ration.

  The method according to the invention can advantageously be applied to a system designed so that at least one path

  of torque transmission has a transmission component

  torque, preferably a toothed pinion which, by the intervention of the synchronization device, will be selectively coupled to the input axis or to the output axis of the

gearbox.

  Furthermore, in the process according to the invention

  * the synchronization device comprises at least one element

  coupling coupling connected in rotation to the input axis or to the output axis of the gearbox and which can be moved by the actuator, as well as at least one synchronization element put in synchronized engagement -

  tion with the torque transmission element when

the coupling element,

  * and once synchronization has been established, the

  beach is connected in rotation with the element

torque transmission.

  Finally, provision is made to produce the actuator to generate an actuating force by excitation of an electric motor and / or by the establishment of a fluid pressure. The present invention will be described below using preferred embodiments shown in the accompanying drawings, in which: * FIG. 1 is a block diagram of a drive system implementing the method of invention, * FIG. 2 is a simplified view of part of the drive system of FIG. 1,

  * Figure 3 is a block diagram of the procedures

  cut in a control device during the

work of the process of the invention.

  According to Figure 1, there will be described a drive system using the method described below in detail for the implementation of speed switches. The drive system 10 of Figure 1 comprises a drive unit 12 for example an internal combustion engine 12 connected by a drive shaft 14 to the input 16 of a friction clutch 18. The output 20 of the friction clutch 18 is connected to

  the input axis 22 of an automatic gearbox, carrying

  as a whole the reference 24. The output axis 26 of the

  gearbox drives the wheels 30, 32 through

diary of a differential 28.

  A control system 34 exchanges data

  born with different actuators. So the installation of

  control 34 is connected to a power control device

  power unit 12 to supply it with appropriate control signals, regulating the power to be supplied or the

  rotational speed (speed) of the power unit 12. The availability

  power adjustment device 36 can relate to any way (or part) of drive unit adjustment, on which one can act to adjust the power, such as for example the injection system, the throttle system, the

  ignition system, cam control or similar means

  logues. The power adjustment device gives information to the control unit 34, characterizing the state

  instantaneous power unit adjustment 12.

  The control system 34 also communicates

  with a regulating device 38 for the friction clutch

  tion 18 constituted here for example in the form of an automatic clutch. To generate the appropriate control orders, the friction clutch 18 can be adjusted in an area between a fully disengaged state and a fully engaged state, to allow more or less slippage between the input 16 and the output 20. The device

  setting 38 can also be designed to provide information

  suitable for the control system 34 and cor-

  corresponding to the setting state, i.e. also to

  the engaged state of the friction clutch 18.

  The control system 34 is also re-

  linked to an actuator 40 of the gearbox 24. The gearbox 24 which is an automatic gearbox, or an automated gearbox, can be controlled by appropriate orders S, to switch between different torque transmission paths between the axis 22 and the output axis 26 of the gearbox; these may for example be gear trains between the two axes. The gearbox 24 may also include a gearshift lever 42 whose actuation is detected by a sensor 44 to be transmitted in the form of an information signal I to the control installation 34. Depending on of this signal

  information I and where appropriate based on other si-

  information signals, a rotational speed sensor 46 which captures the rotational speed of the drive shaft 14, a rotational speed sensor 48 which captures the rotational speed of the drive axis gearbox input 22 and

  a speed sensor 50 which captures the speed

  tesse de rotation of the output shaft 26 of the gearbox-

  ses, the power adjustment device 36, the actuation device 38 of the friction clutch 18 and the actuator 40 of the gearbox 24 are controlled to execute the

switching operations.

  It should be noted that other information signals

  I can be supplied to the control system

  34, for example from the speed sensors

  tation 52, 54 entering the rotational speeds of the wheels

  drive 30, 32, of the temperature sensor which captures the time

  ambient temperature or the temperature of a coolant

  drive unit, a sensor in the accelerator pedal position, a brake actuation sensor or a

  analogous means. From these different data, the

  positive command 34 ensures the operation of the assembly

drive system 10.

  According to FIG. 2, a description will be given of

  cut a possible embodiment of the box

  gears 24. The gearbox 24 comprises as already

  crit above, several torque transmission paths,

  for example in the form of gear trains 56, which ap-

  appear in Figure 2. Gear trains 56 include

  for example, a toothed pinion 58 fixed each time to the axis

  outlet 26 of the gearbox, as well as another

  non-toothed pin 60 which can be selectively coupled, so

  integral in rotation with the input axis 22 of the vi box

  braids by a coupling installation generally bearing the reference 62. The known embodiment according to the state of the art of such a coupling installation 62, to which

  is also associated with a 64-sec synchronization device

ra briefly described below.

  The coupling installation 62 comprises an element 66 connected in rotation with the input axis 22 of the gearbox; a coupling element 68 is connected for example by meshing but with axial sliding, to this element 66. To an interior toothing zone of the coupling element 68 is associated an external toothing segment 70 corresponding, coupled in rotation to the toothed pinion 60. Axially between the element 66 connected integrally to the input axis 22 of the gearbox and the toothed pinion 60 or its toothed segment 70, there is a synchronization ring 72 in principle free in rotation, but with an outer zone having a toothing corresponding to that of the toothed segment 70. If the actuator 40 (indicated diagrammatically) receiving a switching command S, moves a connecting rod 74 associated with the coupling installation 22, the coupling element 68 will be moved in the direction of the toothed pinion 60 thereby pressing the synchronization ring 72 against the toothed pinion 60 or the toothed segment 70. The toothed pinion 60 previously free to rotate by relative to the drive axis 22, accelerates or decelerates until its speed of rotation finally corresponds to that of the input axis 22. At this time, the coupling element 68 is moved axially more towards the toothed pinion 60 until an internal toothing meshes with both the teeth provided on the element 66 and that provided on the toothed segment 70 of the toothed pinion 60, so that the pinion 60 is coupled in rotation to the axis

  input 22 of the gearbox.

  It should be noted that this realization of a

  coupling installation 62 with a synchronization device

  sation 64 has only been described schematically and can be

  performed in multiple ways as a synchro-

  internal synchronization or synchronization

  outside tion. It is also obviously possible that the coupling element 68 is produced to cooperate with two synchronization installations, so that, in the direction of movement of the connecting rod 74, one of the gear trains 56 to be juxtaposed is activated or that the other is disabled. he

  furthermore, it should be noted that the actuator 40 can be reali-

  dried in any manner; it can generate the force of

  translation to translate the connecting rod or the coupling element

  track 68 by excitation of an electric motor, or by

  sending a pressurized fluid for example in a cylinder

  dre sensor, or by magnetic effect, or in another way.

  This device can also include one or more ac-

  and be integrated in the gearbox 24 or

reported to it.

  For the present invention, it is important that the actuator can be placed in different actuation positions and each of these positions then corresponds to an actuation position of the connecting rod or of the installation.

  coupling 62 and synchronization device 64.

  In the implementation of switching according to the principle described above, there are different phases. In a first phase, in which for example the gear train 56 of FIG. 2 has not been activated and that previously another gear train has been activated or that no gear train has been activated , the actuator 40 or

  the coupling element 62 are put in a starting position.

  synchronization rage. This can for example be done in a regulatory procedure in which the position

  instantaneous actuation is detected and decreased

  gradually towards the synchronization start position

  tion, by decreasing the actuation speed. This synchronization start position can be a position in which effectively there is not yet direct contact of the synchronization ring 72 with the toothed pinion 60 or

  for such a position actually starting the synchro-

  However, there is still a certain gap. This posi-

  The start of synchronization can for example be learned beforehand or by a gear change operation executed beforehand. As a variant, as the starting synchronization position, an actuation position is used in which the observation of the speed of rotation of the input axis 22 of the gearbox shows that now due to the modification or activation of the synchronization installation 64, the toothed pinion 60 is coupled to the input axis 22 of the gearbox and thus causes acceleration or deceleration more

strong of this axis 22.

  Once the synchronization start position is

  tion reached, we proceed according to the present invention, as

  this is shown in figure 3. Depending on a situation

  tion of instantaneous driving, for example the way of carrying out a changeover (either in the upward direction, or in the downward direction) or of the mode of driving of the driver who wishes a sporty or economic driving, from a zone of

  memory 80 of the control device 34, a function is extracted

  tion F among a large number of stored functions. The function F is a function which predetermines the evolution over time of the speed of rotation N of the input axis of the gearbox in the synchronization phase proper. When this function F is extracted from memory 80,

  it is adapted using the predetermined boundary conditions.

  These boundary conditions are on the one hand the speed of ro-

  tation N1 of the input axis 22 of the gearbox at

  purpose of the synchronization phase proper, that is,

  say when reaching the starting position of synchronization

  tion, on the other hand the speed of rotation N2 that the input axis 22 of the gearbox will take into account the multiplication ratio of the active gear train 56 after synchronization, and the duration tSYNC available for the synchronization. An adaptation of the preselected function F is thus carried out so as to have, as shown in the middle block of FIG. 3, between the instants: 1, t2 defining the synchronization phase as well as between the rotational speeds N1 at the start and N2 at the end, from the input axis 22 of the gearbox, a continuous or smooth transition, or inflection towards the existing speed conditions. We then arrive at a curve NCONS (t) which is ultimately the evolution over time of the speed

  setpoint rotation of the gearbox input axis

braids in synchronization phase.

  So at time tl, we reach the position of

  synchronization start and the NCONS (t) function is obtained

  naked, so that the control device 34 can supply

  such control signals S to the actuator 40 so that

  in the synchronization phase tSYNC, at each instant t, the actual rotation speed NREEL (t), entered by the sensor 48 at the input axis 22 of the gearbox corresponds to the predetermined rotation speed at instant t, and to The function NCONS (t). There is thus a regulation loop in which the speed of rotation of the input axis 22 of the gearbox is regulated as a function of the evolution over time of the set speed of rotation. Ideally, the actual rotation speed NREEL (t) of the input axis 22 of the gearbox traverses this function as shown in the block in the middle of FIG. 3.

  During the tsYNc synchronization phase, the vi-

  Tesse of rotation of the input axis of the gearbox is however directly related to the actuating force of the actuator 40, generated by this synchronization phase tSYNC. If the actuator 40 generates too strong an actuating force, that is to say if the synchronization 72 is pressed in a relatively strong manner against the toothed pinion 60,

  it is more strongly accelerated or decelerated, that is to say

  say that its rotational speed varies greatly. On-

  keeping an eye on the speed of rotation of the input shaft of the gearbox, we can thus directly observe the force

  actuation generated by the actuator 40.

  If at time t2, that is to say at the end of the predetermined synchronization phase tSYNC, the speed of rotation NREEL (t2) of the gearbox input axis 22 is equal to

  N2, this ensures that the input axis 22 of the gearbox-

  ses and toothed pinion 60 rotate at rotational speed

  N2 determined previously as a function of the rotational speed

  tion of the output shaft 26 of the gearbox and the

  speed reduction port N2 obtained

  by the gear train 56 thus achieving synchronization

  total tion. Determining the rotational speed N2

  can also be done taking into account the speed of the vehicle

  hicle, captured directly or indirectly by the sensors 52, 54. As now we are in total synchronization, we

  can again control the actuator 40 to couple soli-

  dary in rotation the input pinion 60 on the input axis 22 and thus the gear train 56 is ready to transmit the torque. Only then

  the friction clutch 18 previously disengaged, is again

  calf controlled in the direction of the clutch and thus the interruption of traction and pushing in the line of

transmission disappears.

  The method according to the invention provides for the use of

  sation of predetermined functions and their adaptation to the operating state and to the monitoring of the speed of rotation of the input axis 22 of the gearbox, permanently supplied as information concerning the instantaneous state of the operation synchronization. There is no downtime caused by possible buffer periods of

  security that would be created to avoid community shocks

  tation. The choice of the different functions which can for example have different slopes and / or curvatures and for example also thanks to the selection of the time interval between the two instants t1, t2, can be adjusted with a

  any characteristic of a synchro-

  nization, knowing that the shorter this interval and the more the entire synchronization operation will take place in a sporty and reduced comfort; this is advantageous

* in particular for the execution of the rise operations

  wearing in traction mode. For an economical or comfortable ride, you can use a softer curve

  and / or a slower synchronization interval tSyNC.

  Other operating parameters such as ambient temperature, vehicle speed, difference

  rotational speeds between axes 22, 26 or an event-

  Any acceleration of the vehicle can have an influence on the choice of the function or the boundary conditions. The

  driver wants sporty or eco-friendly driving

  nomic can for example be entered by detecting an interrup-

  appropriate or in an adaptive system, by entering

  also the backup actions carried out by the conduc-

  tor, for different components of the drive system 10. It should be noted that all the sensors mentioned

  above and who somehow capture

  rotational braids, can also enter any quantity related to such rotational speeds; in the sensors or in the control installations, by an appropriate calculation, the speed of rotation or a

  quantity representing this for the continuation of the treatment.

  The expression "rotation speed or speed" designates: any quantity defining the rotation speed of a component

determined.

Claims (9)

R E V E N D I C A T I O N S   1) Method for carrying out switching operations in an automatic gearbox (24), having at least one torque transmission path (56) between an input axis (22) e: an output axis (26) of the gearbox with a synchronization device (64), this torque transmission path (56) being selectively activated or deactivated by the control of an actuator (40), method characterized in that to execute a synchronization operation for at least   a torque transmission path (56), the following pes:   a) the actuator (40) is put in the synchro start position   timing, b) as soon as the synchronization start position is   reached, the actuator (40) is controlled during an inter-   synchronization valve (tSyNC) so that the speed of rotation of the input shaft (22) of the gearbox   varies in a predetermined manner towards a rotational speed   final set point (N2), predetermined.   2) Method according to claim 1, characterized in that the method further comprises a step c) so that at the end of   the synchronization interval (tSyNc), the trans-   couple mission (56) goes into a state of preparation for torque transmission.   3) Method according to claim i, characterized in that   in step a), the actuator (40) is put in the position of   part of synchronization by a regulation operation of the actuation position.   4) Method according to claim 1, characterized in that   * in step b) a chronological evolution is predetermined   that (F) for a set speed of rotation   (NCONS (t)), from the input shaft (22) of the gearbox- his, and   * the actuator (40) is controlled in a regulation operation   speed of the gearbox input axis   braids so that during the synchronization time interval (tSYNC), an actual speed of rotation (NREEL (t)), of the input axis (22) of the gearbox,   mainly follows the predetermined chronological evolution   born (F) from the target speed (NcoNs (t)) of   the input shaft (22) of the gearbox.    ) Method according to claim 4, characterized in that the setpoint rotation speed (NCoNs (t2)), predetermined for the end of the synchronization interval (tsYNC) of the input axis (22) of the box of speeds corresponds to the   final set speed (N2).   6) Method according to claim 4 or 5, characterized in that the chronological evolution (F) of the target speed of rotation (NcoNs (t)) of the input axis (22) is predetermined.   gearbox according to operating condition.   7) Method according to claim 6, characterized in that in step b), from several speed functions   setpoint / time rotation (F), depending on the operating state   tion, a function is selected to predetermine the chronological evolution (F) of the rotation speed of   setpoint (NcoNs (t)) of the input shaft (22) of the gearbox   braids. 8) Method according to claim 6 or 7, characterized in that   the operating state is defined by at least one of the pa-   following rameters: * speed of rotation of the output shaft (26) of the gearbox, * driving speed, * driving mode: sporty / economical, * transmission ratio of the torque transmission path (56 ) to activate, * nature of the gear change: upshifts / downshifts, ò temperature.   9) Method according to claim 7 or claim 8 linked to claim 7, characterized in that the function (F) selected to predetermine the chronological evolution (F) of the reference speed of rotation (NCoNs (t)) of the input axis (22) of the gearbox is further adapted according to one of the following parameters: * synchronization time interval (tsyNc) * actual rotation speed (NREEL (tl)) of the axis input (22) of the gearbox at the start of the synchronization interval, * speed of movement, * speed of rotation of the output shaft (26) of the gearbox,   * transmission ratio of the transmission path of ple to activate (56)    ) Method according to any one of claims 1 to 9, characterized in that   the synchronization time interval (tSyNC) is varied corn.   11) Method according to any one of claims 1 to 10, characterized in that   the synchronization time interval (ItSyNC) is selected   at least according to one of the following parameters:   * nature of the gear change: my- tee / descent,   * driving mode: sporty / economical.   12) Method according to any one of claims 1   to 11, characterized in that the synchronization start position is an actuation position of the actuator (40) which has an offset from the actuation position for which starts actually a synchronization.   ) Method according to any one of claims 1   to 12, characterized in that at least one torque transmission path (56) comprises a torque transmission component (60), preferably a   toothed pinion (60), which is coupled with intervention of the dispo-   synchronization device (64), selectively on the axis   inlet (22) or the outlet shaft (26) of the gearbox-   his. 14) Method according to claim 13, characterized in that * the synchronization device (64) comprises at least one coupling element (68) connected in rotation to the input axis (22) or to the axis of gearbox outlet (26) which can be moved by the actuator (40), as well as at least one synchronization element (72)   synchronized with the trans-   torque mission (60) during the movement of the coupling element (68),   * and once synchronization has been established, the   beach (68) is integrally connected in rotation with   the torque transmission element (60).    ) Method according to any one of claims 1 to 14, characterized in that   the actuator (40) is designed to generate a driving force   works by the excitement of an electric motor drive   or / and by establishing a fluid pressure.