FR2901334A1 - METHOD FOR CONTROLLING A DEVICE FOR COUPLING TWO CRABOTS - Google Patents

Abstract

The invention relates to a method for controlling a coupling device for two claws rotating about the same axis and each formed teeth (9, 10), the claws being capable of meshing under the action of a mechanism allowing the translational movement of one of the jaw said movable dog relative to the other dog said fixed dog, the translation being along the axis of rotation of the jaw. The method consists of sequencing the following phases: in a first phase of contactless approach of the mobile clutch relative to the fixed clutch, to apply a maximum force (Umax) allowing the translation of the mobile clutch, - during a second phase during which the top of the teeth (10) of the movable clutch is likely to touch the top of the teeth (9) of the fixed clutch, to reduce the effort (Umin) allowing the translation of the mobile clutch, - in a third phase during which a flank of the teeth (10) of the movable clutch is likely to touch a flank of the teeth (9) of the fixed clutch, to apply a maximum force (Umax) allowing the translation of the movable clutch.

Description

for the driver of a vehicle equipped with such a box

  speeds in a shift phase. The actuating device 5 further comprises a drive mechanism in translation of the clutch 7 to perform either a clutch, self-clutching. To avoid overloading the figure, the steering mechanism is not shown. Arrows 14 nevertheless show the movement of the clutch 7 to obtain the interconnection. With the integration of computers on traction power sources, whether it is a thermal or electrical engine and also with the implementation of automated gearshift actuation chains, the driver no longer acts directly. on the claws which are manipulated by another source of electrical or hydraulic energy for example. With also the implementation of position sensors and speed to know precisely and at any time the relative speed between the two jaw 6 and 7 in rotation and in translation, steering gear change becomes easier. Thanks to these new means, mechanical synchronization mechanism using the cones 12 and 13 shown in FIG. 1 can be dispensed with. It is quite possible to reconstitute the synchronization by setting up a control algorithm ensuring the synchronization between the gearshift device and the traction motor concerned by the shift and the vehicle load. Such a simplification, represented in FIG. 2, makes it possible in particular to simplify the gearbox, to reduce its size and to limit its cost.

  Now it has been found that according to the relative angular positioning of the claws 6 and 7 relative to each other at the time of contact between their respective teeth, there appears a strong dispersion over time to perform the interconnection. For the driver, this dispersion is very sensitive and is a source of discomfort and therefore felt negatively by the driver.

  The object of the invention is to solve this problem by proposing a new method of controlling a jaw coupling device which makes it possible to reduce the duration of interconnection as well as to reduce the dispersion of this duration. For this purpose, the subject of the invention is a method for controlling a coupling device for two jaw claws rotating about the same axis and each formed with teeth, the claws being capable of meshing under the action a mechanism allowing the displacement in translation of one of the jaw, said movable dog, relative to the other dog, said fixed dog, the translation being along the axis of rotation of the jaw, characterized in that the method consists in linking the following phases: during a first approach phase without contact of the movable dog relative to the fixed clutch, to apply a maximum force allowing the translation of the mobile clutch, during a second phase during which the vertex of the teeth of the mobile dog is likely to touch the top of the teeth of the fixed dog, to reduce the effort allowing the translation of the mobile dog, and - during a third phase during which a flank of the teeth of the mobile dog is susceptible tible to touch a flank of the teeth of the fixed clutch, to apply a maximum force allowing the translation of the movable clutch. For the first phase, it is possible to predetermine its duration from an average time required for the contactless approach of the mobile clutch relative to the fixed clutch. It is also possible to define the end of the first phase as a function of information received by a sensor measuring the translational movement of the mobile clutch. Advantageously, the mechanism for translational movement of the movable clutch comprises an actuator. During the first phase and the third phase, the actuator is commanded to the maximum of its possibilities. Advantageously, the duration of the second phase is predetermined from an average time required for a tooth of the mobile dog to move angularly around the axis of rotation of the jaw by an angle equivalent to an angular width of a tooth .

  The method may comprise another phase following the third phase. During this other phase the mobile clutch is enslaved in the position taken by the mobile clutch end of the third phase. Advantageously, prior to the first phase, the relative angular velocity of the two claws is brought substantially to a given value.

  In a variant of the method according to the invention, a mobile dog with large teeth and a fixed clutch equipped with both large teeth identical to the teeth and in addition to small teeth of the same shape as the large teeth in a tooth are used. reduced size and formed in the recesses between large teeth, the method being characterized in that during the third phase, it consists in momentarily increasing a torque applied to the fixed clutch so as to force the establishment of a contact between the teeth of the mobile dog and the large teeth of the fixed dog and to avoid the establishment of contact between the teeth of the mobile dog and the 1 o small teeth of the fixed claw. The momentary increase in torque can be followed by a momentary cancellation of the torque. This cancellation of the torque facilitates the end of the stroke of the teeth of the mobile clutch. According to another variant, the method according to the invention implements a mobile dog provided with large teeth and a fixed dog provided with both large teeth identical to the teeth and in addition to small teeth of the same shape as the large teeth in The method is characterized in that the second phase only concerns the large teeth of the fixed clutch, in that the third phase is followed by a fourth phase during which the clutch is reduced. the force allowing the translation of the mobile clutch when the top of the teeth of the mobile clutch is likely to touch the top of the small teeth of the fixed clutch, and in that the fourth phase is followed by a fifth phase identical to the third phase.

  The invention will be better understood and other advantages will appear on reading the detailed description of an embodiment given by way of example, a description illustrated by the accompanying drawing in which: FIG. 1 schematically represents a device dog clutch coupling comprising a synchronization mechanism; - Figure 2 shows schematically a claw coupling device without synchronization mechanism; (Figures 1 and 2 have been previously described to illustrate the prior art) - Figure 3 schematically shows an example of a clutch coupling device to which the invention can be applied; - Figures 4 and 5 show possible configurations of the teeth of the jaw before jaw clutch; - Figure 6 shows different possible cases of relative positioning of the teeth of the claws at the time of contact with the teeth; FIG. 7a represents, in chronogram form, a control voltage of a motor operating one of the claws; Figure 7b shows the disposition of the teeth corresponding to the chronogram of Figure 7a; - Figure 8 schematically shows characteristics of an engine implemented in a mechanism for translational movement of the mobile clutch; FIG. 9 represents the relative position of the jaw teeth during the different phases of a process according to the invention; - Figure 10 illustrates the method in the case where the fixed clutch is provided with large and small teeth; and - Figure 11 illustrates a variant of the method in the case where the fixed clutch is provided with large and small teeth.

  For the sake of clarity, the same elements will bear the same references in the different figures.

  FIG. 3 represents a jaw coupling device without a synchronization mechanism and taking up the various elements of the device of FIG. 2, namely the shafts 1 and 2, the pinions 3 and 4 and the dogs 6 and 7. The shaft 1 is for example an input shaft of a gearbox and is connected to a traction motor 18 thermal or electrical. The shaft 2 is for example an output shaft of the gearbox and is connected to the wheels of a vehicle equipped with the gearbox. The drive mechanism in translation of the clutch 7 comprises an electric motor 20 and a barrel 21 driven by the electric motor 20 via a speed reducer 22. The barrel 21 is hollowed by at least one track 23 in which a finger 24 can slide. The track 23 has for example a helical shape around a shaft 25 of rotation of the cylinder 21. The finger 24 is secured to a fork 26 driving the dog 7 in translation along the shaft 2. The translational movement of the fork 26 is represented by the arrow 27. In FIG. 3, a curve 28 is shown showing the relationship, defined by the profile of the track 23, between the rotation angle e of the shaft 25 and the displacement in translation of the finger 24 along an axis z parallel to the shaft 2. The mechanism further comprises a first angular speed sensor 30 of the rotation of the shaft 25 a second angular speed sensor 31 of the rotation of the shaft 1 and a third angular speed sensor 32 of the rotation of the shaft 2. The sensors 30, 31 and 32 transmit to a computer 33 the rotational speeds of the shafts 1, 2 and 25. The computer 33 makes it possible in particular to control the motors 18 and 20. Figures 4 and 5 show respectively vertically two examples of shape of the teeth 9 and 10 respectively belonging to the jaw 6 and 7. The teeth 9 and 10 are positioned regularly on the same mean radius around the axis of the shaft 2 so that the teeth 10 of the clutch 7 may be inserted in recesses formed between the teeth 9 of the clutch 6. It is assumed that the number and shape of the teeth 9 and 10 of each clutch 6 and 7 are identical. It is quite possible to implement the invention in other geometrical configurations of teeth and in particular in the case where the clutch 7 is provided with large teeth similar to the teeth 10 and the other clutch 6 is provided with both large teeth 36 identical to the teeth 35 and in addition to small teeth 37 of the same shape as the large teeth 36 in a reduced size and formed in the recesses formed between the large teeth 36 as shown in Figure 5. Each tooth comprises two types of faces, flanks and a vertex. Each tooth 10 has two flanks 40 and 41 whose normal axis is substantially perpendicular to the axis of translation of the claws 6 and 7. The flanks 40 and 41 may be slightly inclined at an angle Of, as shown in FIG. to produce an effect opposing declutching. The angle Of is advantageously less than 10. The flanks 42 and 43 of the teeth 9 are parallel to the corresponding flanks, respectively 40 and 41, of the teeth 10. Each tooth 10 has a vertex 44 whose shape is substantially included in a plane whose normal axis is parallel to the axis of translation of jaw 6 and 7. The shape of the vertex 44 may for example be curved but for reasons of simplicity it is considered that the vertex 44 has two plane faces 44a and 44b symmetrical with respect to a plane of symmetry of the flanks 40 and 41 The two faces are inclined at an angle, advantageously less than 15.

  Each tooth 9 also has a vertex 45 similar to the apex 44. As before, it can also be considered that the vertex 45 has two flat faces 45a and 45b. The curved shape, modeled by the flat faces 44a, 44b, 45a and 45b produced in the event of contact of the crown-to-apex teeth, is an increase in the difference in angular velocity between jaws (in this case the surface promotes the angular movement between teeth) , or a decrease in angular velocity between jaw (in this case the surface opposes the angular movement between teeth). Depending on the position and the initial relative angular velocity between the two claws, several geometrical contact configurations of the teeth facing each other are possible during the clutching: a) Tooth contact on the tooth tip with orientation of the tooth crown surface promoting the relative angular movement between jaw. c) Tooth-to-tooth contact with tooth tip surface orientation opposing relative angular movement between jaws. b) Flank contact on the side of the teeth. In this case, the teeth are positioned directly in their respective hollow. In FIG. 4, there is shown in bold line a curve-envelope 46 of the possible positions of a point O located in the middle of the apex 44 of the tooth 10 during the contact of the teeth 9 and 10 during the interconnection. The envelope 46 makes it possible to statistically predict the probability of having one of the three configurations a) b) and c) previously described. The casing 46 is shown at an angular length c about the axis of rotation of the claws equal to 2rr / n, where n represents the total number of teeth of one of the claws. In a first portion 46 (1) of the casing 46 of angular length a, it is in the first configuration a) of tooth-to-tooth-to-tooth contact with orientation of the tooth-crown surface promoting relative angular movement between jaw. In a second portion 46 (2) of the casing 46 of angular length b, it is in the second configuration b) flank contact on the side of the teeth. In a third portion 46 (3) of the casing 46 of angular length a, it is found in the third configuration c) of tooth-to-tooth-to-tooth contact with orientation of the tooth-crown surface opposing the movement relative angular between jaw. It can be seen that the probability b / c of configuration b) flank on flank is much lower than the probability of the two other configurations a) and c) since b represents the clearance between the angular length of the spaces between teeth and teeth width, set that we want to limit including for reasons of comfort and pleasure of driving the vehicle. By defining the clutching time as the time taken by the claws to reach the position where the contact between teeth 9 and 10 is effective flank on flank, it is obvious that the shortest time will be obtained if the sidewall configuration flank present first in phase of interconnection.

  Unfortunately, this situation is the least likely. In most cases, the claws end up in a tooth-topped configuration, which not only generates shock but also a waste of time. By way of illustration of the foregoing, a casing curve 50 has also been shown in FIG. 5. FIG. 6 shows various possible cases during the interconnection, obtained with a control of the motor 20 of the control mechanism in translation of the clutch. 7 of open loop type, constantly feeding it to its maximum voltage. These cases are as much a source of dispersion in the times obtained by interconnection. FIG. 6 represents different relative positions of the two claws 6 and 7. For each case, the positions chronologically follow one another from the top to the bottom of FIG. 6. Arrows show the relative movement of a tooth 10 with respect to a tooth 9 In the case of No. 1, a tooth-to-tooth contact on the tooth top is obtained, favoring the increase of the angular velocity between jaws. After this contact, the teeth fall into their respective hollows and then support flank on flank. In the case n 2, the teeth fall directly into their respective hollow and then rest flank on sidewall As explained above the time of interconnection is here very short but the probability of occurrence of the case n 2 is very low. In case No. 3, a tooth-to-tooth-to-tooth contact is first obtained, opposing the relative angular movement between jaws.

  In a first step, the relative angle continues to increase resulting in an inversion of the movement (therefore the speed) of translation between teeth (ascent of the tooth 10). In a second step, the relative angle stabilizes and then decreases (thus the angular relative speed is reversed) so that the translation movement is reversed again (inversion of the translation speed). Finally the teeth fall into their respective hollow and then support flank on flank. In case No. 4, as in case No. 3, a tooth-to-tooth-to-tooth contact is obtained opposing the relative angular movement between jaw. But this time, unlike in case 3, the relative angular movement between jaw is not reversed. At first, the translational movement between jaws reverses to cause a rise of the tooth 10. In a second time after passing to the top of the tooth, the translation movement is reversed again to cause a descent of the tooth 10 on the opposite side. (Finally, the teeth fall into their respective hollows and then come into contact flank on the flank.) Among all these situations, case # 3 is the one that leads to the longest interconnection time. the time of interconnection according to the case encountered, in particular between case n 2 and case n 3.

  The method according to the invention consists in proposing a control of the motor 20 of the control mechanism in translation of the clutch 7 reducing the time of interconnection. The dispersion of the clutch time is also reduced. To achieve this goal, the method eliminates the case n 3 by seeking to avoid the opposition to the relative angular movement between jaw during a tooth-to-tooth contact tooth tip while minimizing at that time the tooth on tooth support which is at the source of the resistance effort. In this way the movement is only slightly disturbed, the case n 3 can no longer occur and we therefore return to the case n 4. To do this, the method generally consists of reducing very strongly for a given time Ot , the force applied on the claws in tooth tooth contact tooth tip. This reduction of effort is obtained by reducing the control setpoint of the motor 20. The evolution over time of this setpoint is represented in FIG. 7a in the form of a voltage U and the corresponding translation of the mobile clutch 7 is represented. in Figure 7b. At an initial moment, the point 0, the middle of the vertex 44 of a tooth 10 is at the coordinate X0. From the initial moment and until time t1 the voltage U is maximum, it is denoted Umax. This is the first phase of the process. At the moment t1, the point O reaches the dimension X1 corresponding to a possible contact tooth vertex on tooth tip. From time t1 and up to a time t2, the voltage U is greatly reduced to a value Umin. This is the second phase of the process. During this phase, the position of the point O evolves little and its dimension remains close to X1. Then, from time t2, the voltage U is increased to reach the value Umax again. The instant t1 end of the first phase can be predefined. A model for calculating this instant uses characteristics of the motor 20 represented diagrammatically in FIG. 8. In this figure, I represents the total inertia of the mechanism for translational control of the clutch 7 brought back to the level of the motor 20, R resistance. motor 20 and Ke the electromagnetic gain of the motor 20. At first approach, it does not take into account the inductance of the motor 20. Indeed, it is considered that the inductance, affects only very little on the dynamic behavior of the engine 20. Neither do the different friction of the mechanism be taken into account. This friction is negligible in view of the electromagnetic torque of the motor 20. The reduction ratio r between the motor angle and the position of the movable clutch 7, of the current i flowing in the motor 20 is also taken into account. The kinematic parameters are noted from FIG. following way: x, the current position of the point O in its translation, as the angular speed of the motor 20 and 6m the angular position of the motor 20. We have: R x = rOn, from equations (1) and (2) we can write: 2 U dw Ke w = KJ + max (4) dt R me R We fix the initial conditions: wn, (1 = 0) = 0 (5) and 0n, (t = 0) = 0 (6 ) and the condition for t = t1: Bm (t = t,) =, x (7) r To simplify the writing, a parameter zn is introduced, linked to the parameters of the engine 20: (on, (t) ù Umax Ke By integrating equation (9) we obtain: 6m (t) = Umax t ù Zmu e Tn, (10) By applying equation (10) at time t1, we obtain: rr \ xl Umax 1- e T (11) r Ke 15 The exponential of equation (11) can be app roximée by its limited development: n, -1- t, it '(12) Zm 2 m

from where 2 1-e "'l t, (13) 2 rm

  An approximate formulation of t1 is obtained:

  t, = / 2rn x, Ke = / 2- x, I (14) Umax r Ke Umax / R This calculation model of t1 makes it possible to avoid any recourse to the angular velocity sensor 30. It is also possible to use the sensor 30 to define the instant t1. Zm = J` (8) Ke ~ R

  Solving the differential equation (4) yields: r \ (9) 1u In the same way, the duration Ati of the second phase can be predefined. The motor 20 of the drive mechanism in translation of the clutch 7 is modeled as previously by I, the total inertia of the drive mechanism in translation of the clutch 7 brought back to the motor 20, R the resistance of the motor 20 and Ke the electromagnetic gain of the motor 20. To these parameters is added: r the reduction ratio between the motor angle 20 and the movable clutch position 7 along the axis of the shaft 2, p the coefficient of sliding of the tooth crown on top of the tooth , rt the mean radius of positioning of the teeth 9 and 10 about the axis of the shaft 2, the inertia of the traction motor 18, wm the angular speed of the motor shaft 20, em the angular position of the motor shaft 20, i the current flowing in the motor 20, x the relative position in translation of the teeth of the movable clutch 7 along the axis of the shaft 2, C the resistant torque on the motor 20 linked to the top contact of tooth on top of the tooth, Fn the normal force along the axis of the shaft 2 on the teeth 9 on the part of the teeth 10 during the tooth-to-tooth-to-tooth contact, Ft the tangential force on the teeth 9 on the part of the teeth 10, the force perpendicular to the force Fn, Ct the contact-resistant torque Tooth top on tooth top on traction motor 18 and wt traction motor speed 18.

  The general operation of the motor 20 is expressed by the following equations: d wn, dt-C (15)

ù

  min em (16) 1 = R x = r0 ,,, (17) C = rF (18) During the second phase, in the case of the tooth-to-tooth tooth contact, the teeth 9 and 10 being substantially flat ( low angle of curvature), it can be considered that the motor 20 is blocked by a torque C. It is therefore: 25 dt. ': - "0 (19) and w ,, -0 (20) The speed and the acceleration of the motor 20 being zero, we deduce the expression of the torque C: C = KQ URin (21) Umin, representing the control voltage applied to the motor 20 during the second phase.

  The torque C is reflected on the teeth by a bearing force Fn on the contact which itself generates a tangential force Ft resistance to angular movement between jaws Ft = pFn (22) It is deduced that: Umin (23) r and therefore: C, = (24) By writing that the speed and acceleration of the motor 20 are zero, we deduce the expression of the torque Ct. Taking into account the average radius rt on which the teeth are placed, we deduce then the torque generated by the motor 20 against the inertia Jt in the rotational movement of the jaw. At the ratio of reduction ready between gears, the inertia Jt is that of the traction motor 18. In fact, the shaft 2, in relation to the wheels, is considered at almost constant speed, its inertia being very large compared to the Inertia Jt of the traction motor 18. In other words: jd ~, = - C, (25)

  C, = r, F (26) and and 4t, = Awin '~~ wini ù 2C, 1 = - 21 Owini + 1 / to ù 2C, l (30) Finally, everything comes down to solving the differential equation ( 25) governing the movement of the traction motor 18 for which it is assumed here that no additional torque (other than the resistance torque generated by the motor 20) is applied during At ,. In defining Owin; the angular velocity difference between the two claws 6 and 7 at time t1, and I the angular width of a tooth 9 or 10, we have during the second phase: Aw, (t) _uC, (tt,) + Ao (27) and AO, (t) = ù'C, (tùt,) 2 + Awini (t - t,) (28) We deduce that: - - C, At, 2 + Aw, n, Ot , -1 = 0 (29) The expression of At1 involves the dynamic parameters of the mechanism for translational movement of the movable clutch 7 and also the initial angular differential speed A, win; between jaw. The knowledge of the latter requires the use of two speed sensors 31 and 32 respectively placed on the shafts 1 and 2. A simplified expression of At1 can be obtained by neglecting the resisting torque caused by the motor 20. In this case the duration Lt1 25 simply corresponds to the ratio between the tooth angular width I and the initial angular velocity λw; n; FIG. 9 represents the relative position of the teeth of the dogs 6 and 7 during the various phases of the process as a function of the voltage U (31) applied to the motor 20. It is placed in the situation that would have resulted in case 3 in the absence of the method of the invention. At the initial moment t = 0, the point O of the tooth 10 is at the coordinate Xo and the voltage Umax is applied to the motor 20 until the instant t1. Between times t1 and t1, point O moves to dimension X1. Between times t1 and t2, the voltage U is reduced to a value Umin and the tooth 10 has an angular velocity represented by the arrow 60. Although during this period, a tooth-to-tooth-to-tooth contact is first obtained opposing the relative angular movement between jaw, the angular movement of the jaw does not reverse and the point O exceeds the top of a tooth 9 before the time t2. The decrease of the voltage U minimizes the contact force between the teeth 9 and 10. Between the times t2 and t3, the voltage U is again raised to the value Umax and the tooth 10 can be inserted between two teeth 9. The point O goes from X1 to X2.

  In this control method, the time of interconnection will be shorter as the difference in angular velocity between jaw 6 and 7 will be large. Indeed, after application of this method, the most penalizing case is the case n 4 for which a large part of the time is linked to the existence of the tooth toe contact on tooth tip first on the opposite side to the movement angular then on the face favoring the angular movement. The greater the difference in angular velocity, the shorter this time will be. In practice, it is not possible to increase the speed difference beyond a certain threshold essentially for reasons of mechanical strength of the teeth and also of approval.

  This control method advantageously requires knowledge of the relative angular velocity difference between the claws 6 and 7. To do this, it is piloted before the first phase, the angular speed of the traction motor 18 to achieve a desired relative speed between the jaw 6 and 7. Then during the interconnection, (phase 1 to 4), it is no longer necessary to drive the traction motor. This has the advantage of decorrelating the control of the traction motor 18 and the control of the mechanism allowing the displacement in translation of the mobile clutch 7. The method makes it possible to reduce on average the clutch time, even if in certain situations the method increases. For example, in case n 1 and case n 2, the shortest clutching time is, in principle, obtained for a maximum motor voltage U permanently applied. Nevertheless, we note that the increase in interconnection time for cases 1 and 2 remains moderate. The main advantage of the method lies in the fact of limiting the differences between the interconnection times noted in the different cases. For reasons of protection and precision, the motor 20 is often provided with a local loop for regulating the dynamic current greater than the dynamics involved in the entire mechanism for translational movement of the mobile clutch 7. 1 o In this case, the control method can still be applied without significant modification simply by adapting an algorithm operating the computer 33. In the first phase of the method, the current setpoint must be placed as large as possible in order to saturate voltage control at full voltage. In the second phase of the process (from t1 to t2), the current setpoint is set to the Imin value to generate a sufficiently small contact force to limit the possible decrease in the movement, but large enough to prevent a detachment of the surface from contact 20 between the tops of the teeth. The speed of the motor 20 is virtually zero in this second phase, under the effect of tooth to tooth contact tip contact, the motor voltage is limited to Umin = R.Imin. The motor voltage remains virtually constant on this second phase of the process.

In the third phase of the process (from t2 to t3), the current setpoint is again set to its maximum so as to saturate the control voltage again at full voltage. In the variant illustrated in FIG. 5, the clutch 7 is provided with large teeth 35 similar to the teeth 10 and the other clutch 6 provided both with large teeth 36 identical to the teeth 35 and in addition to small teeth 37 likewise. as large teeth 36 in a reduced size and formed in the recesses between large teeth 36. A method according to the invention can still be applied in a simple way to facilitate only the relative angular movement between jaw in contact phase large tooth 35 35 on large tooth 36. It is then always possible that the relative angular movement is braked in the contact phase large tooth 35 on small tooth 37, causing an increase in the time of interconnection. It is possible to overcome this problem by driving the traction motor 18 so as to produce a torque increasing the relative angular position of the claws 6 and 7 from the moment when the relative position in translation of jaw 6 and 7 has reached the position x ,,, marking the beginning of the recesses between the large teeth 35 and 36. This process is illustrated in FIG. 10. This increase in so-called torque torque is intended to cause a systematic sidewall to flank contact, large tooth against large tooth 36, to position the teeth 35 and 36 suitably against each other and complete the movement of interconnection. The value of the torque must result from a compromise between speed of action to obtain the flank edge contact, minimizing the force to be applied to the motor 20 which is directly related to the value of this torque and minimizing the impact between flanks, source of discomfort for the driver.

In particular to facilitate the interconnection, it is possible to cancel during the time necessary for the end of the clutch the over-torque applied to the traction motor 18 as soon as the relative angular speed between the claws has been canceled, marking the flank-side contact. This cancellation of the torque facilitates the end of the stroke of the teeth 35 of the mobile clutch 7.

Over-torque can very well occur in the phase of limiting the voltage U and / or current of the motor 20, without this being a problem. FIG. 11 illustrates another method making it possible to facilitate the interconnection of a device as illustrated in FIG. 5. The method consists in reducing the force allowing the mobile dog 7 to be translated twice: once to facilitate angular movement in contact phase large tooth on large tooth and once to facilitate the angular movement in contact phase large tooth on small tooth. The control of the motor 20 is then broken down as follows: In a first phase, the motor 20 is controlled under full voltage Umax to minimize the clutch time. In a second phase when the position x1 has been reached, the control voltage is limited to avoid the case 3 of FIG. 6 when the apex of the large teeth 35 comes into contact with the apices of the large teeth 36. The duration At, of this second phase is calculated as above using the knowledge of the difference in angular velocity between jaw 6 and 7. At the end of the time Lti, and if the dimension x2 was not reached by the point O of the teeth 35 of the mobile clutch 7, it controls again the motor 20 in full voltage Umax to minimize the clutch time. As soon as the point O has reached the dimension x2 and without necessarily the time At1 has elapsed, it limits the engine control for a time At2. At2 is calculated as tt1 by considering as the angular width, not the width I of the large tooth 36, but the sum of the half-width 1/2 of the large tooth 36 and the half-width 1/2 of the small tooth 37. The calculation of At2 again requires the use of the speed sensors 31 and 32 of the shafts 1 and 8 to estimate the difference in angular velocity between claws 6 and 7. At the end of time At2, we command again the Umax 20 to 15 full voltage motor to minimize jaw clutch time. Finally as soon as the point O has reached the dimension x3 (use of the angular position sensor 30), it is switched to a regulation in position of the motor 20 to stop the mobile clutch 7 in its position of interconnection. 20

Claims (10)

  1. A method of driving a coupling device of two jaw (6, 7) rotating about the same axis (2) and each formed teeth (9, 10; 35, 36, 37), the jaw ( 6, 7) being able to mesh under the action of a mechanism allowing the displacement in translation of one of the jaw said mobile clutch (7) relative to the other clutch said dog clutch (6), the translation along the axis (8) of jaw rotation, characterized in that the method consists of sequencing the following phases: during a first approach phase without contact of the mobile clutch (7) io with respect to fixed dog (6), to apply a maximum force (Umax) allowing the translation of the movable clutch (7), - during a second phase during which the top of the teeth (10, 35) of the mobile clutch (7) is susceptible touching the top of the teeth (9, 36) of the fixed dog (6), reducing the effort (Um; n) allowing the translation of the mobile dog (7), and at a third ph during which a flank (40) of the teeth (10, 35) of the mobile dog (7) is capable of touching a flank (42) of the teeth (9, 36) of the fixed dog (6), to apply a maximum force ( Umax) allowing the translation of the mobile clutch (7). 20   2. Method according to claim 1, characterized in that the duration of the first phase is predetermined from a mean time (fi) necessary for the approach without contact of the mobile clutch (7) relative to the fixed clutch (6). ).   3. Method according to claim 1, characterized in that the end (t,) of the first phase is defined as a function of information received by a sensor (30) measuring the translational movement of the mobile clutch (7). 30   4. Method according to one of the preceding claims, characterized in that the mechanism for translational movement of the movable clutch (7) comprises an actuator (20), and in that during the first phase and the third phase, the actuator (20) is controlled to the maximum (Umax) of its possibilities. 25   5. Method according to one of the preceding claims, characterized in that the duration (An) of the second phase is predetermined from an average time required for a tooth (10, 35) of the mobile clutch (7) for angularly move about the axis (8) of rotation of the claws by an angle equivalent to an angular width (I; I ') of a tooth (10, 35).   6. Method according to one of the preceding claims, characterized in that it comprises another phase following the third phase, another phase during which the mobile clutch (7) is slaved in the position taken by the mobile clutch (7). at the end of the third phase.   7. Method according to one of the preceding claims, characterized in that prior to the first phase, the relative angular velocity (Aw; n;) of the two jaw (6, 7) is brought substantially to a given value.   8. Method according to one of the preceding claims, implementing a mobile clutch (7) provided with large teeth (35) and a fixed dog (6) provided with both large teeth (36) identical to the teeth (35). ) and in addition to small teeth (37) of the same shape as the large teeth (36) in a reduced size and formed in the recesses between the large teeth (36), the method being characterized in that during the third phase, it consists in momentarily increasing a torque (Ct) applied on the fixed dog (6) so as to force the establishment of a contact between the teeth (35) of the movable dog (7) and the large teeth (36) of the clutch fixed (6) and to avoid the establishment of a contact between the teeth (35) of the mobile dog (7) and the small teeth (37) of the fixed dog (6). 30   9. The method of claim 8, characterized in that the momentary increase in the torque (Ct) is followed by a momentary cancellation of the torque (Ct).   10. Method according to one of the preceding claims, implementing a mobile dog (7) provided with large teeth (35) and a fixed dog (6) provided with both large teeth (36) identical to the teeth (35). and in addition to small teeth (37) of the same shape as the large teeth (36) in a reduced size and formed in the recesses between large teeth (36), the method being characterized in that the second phase only concerns large teeth (36) of the fixed claw (6), in that the third phase is followed by a fourth phase during which the effort (Umin) is reduced allowing the translation of the clutch 1 o mobile (7) when the top of the teeth (35) of the mobile dog (7) is likely to touch the top of the small teeth (37) of the fixed dog (6), and in that the fourth phase is followed by a fifth phase identical to the third phase. 15