WO2002021016A1

WO2002021016A1 - Transmission device, in particular for motor vehicle

Info

Publication number: WO2002021016A1
Application number: PCT/FR2001/002761
Authority: WO
Inventors: Cyrille Benais
Original assignee: Antonov Automotive Technologies B.V.
Priority date: 2000-09-06
Filing date: 2001-09-06
Publication date: 2002-03-14
Also published as: FR2813649B1; AU2001287812A1; FR2813649A1

Abstract

A planet pinion cage (22) mounted on a free wheel (101) bears multistage planet pinions (24) with one primary stage (26) meshing with a primary planetary gear (11) linked to an input shaft (4) via a two-ratio automatic gear shifting mechanism (108) and an input clutch (12). The torque is transmitted to the output shaft (6) via one or the other of the three secondary stators (41, 42, 43) depending on the state of the corresponding selective coupling devices (57, 58, 61). The multiplicative variation between two successive ratios defined by the differential gear (21) thus produced is equal to the square of the multiplicative variation between the two ratios in the mechanism (108). Thus, the transmission device defines a six-ratio transmission device with automatic gear shift utilising the axial thrusts of the teeth (PAC, PAS1 and PAS2) as measurement of the torque transmitted and using centrifugal counter-weights (86, 87, 127) to apply control forces constituting a measurement of the rotational speeds.

Description

DESCRIPTION "Transmission device, in particular for the automobile" The present invention relates to a transmission device, in particular for the automobile. The present invention relates more particularly to an automated transmission device having a particularly simple and economical structure for producing relatively numerous transmission ratios.

Another object of the present invention is the production of a transmission device which, even by offering numerous transmission ratios, can be easily automated according to the "ANTONOV" principle as described in particular in WO-A-92 07206, 94 1 9626, 96 06293, 97 08478, 99 1 3247, and in application FR 99 051 38 not yet published.

The "ANTONOV" principle can be summarized as follows: in a differential mechanism, a clutch has a torque transmission capacity determined by a fixed or variable clamping force. Preferably, said clamping force increases with a speed of rotation in the differential mechanism. The clutch thus has a torque transmission capacity which increases with the aforementioned rotation speed. When the torque to be transmitted exceeds the current transmission capacity, the clutch slips until a subsidiary coupling device, such as a freewheel, makes another coupling in the transmission, corresponding to another gear ratio. transmission by the differential mechanism. The backlash generated by this new operation of the differential mechanism is used to open the clutch during slippage so as to eliminate any friction in the differential mechanism operating according to the new ratio. If for example the aforementioned rotation speed increases and / or the torque to be transmitted decreases, the clutch tightening force can overcome the loosening force produced by the toothing reaction and close the clutch so as to recreate the conditions of operation originally described. These conditions correspond to a suppression or a reduction of the toothing reaction. Thus, the clamping force, initially just sufficient to overcome the toothing reaction force, can then effectively close the clutch with a clamping force and therefore a torque transmission capacity determined as a function of the rotation speed.

In the examples described in the previous documents, the ANTONOV transmissions are produced in the form of two-speed planetary trains operating in direct drive when the clutch is tightened or in reduction gears otherwise. Typically, the number of planetary trains required is at least half the number of gears offered by the transmission.

According to the invention, the transmission device comprises:

- an input tree; - an output shaft;

- a differential gear in which a stage satellite mounted on a planet carrier comprises at least two stages of toothing each meshing with a respective one of several axial forward gears located on the same side of the satellite while some of the toothing stages further meshes with an axial reverse gear, located on the other side of the satellite;

- Connection means between on the one hand at least one primary toothing forming part of the axial toothing forwards and on the other hand a first of the input and output shafts; - Selection means for selectively connecting the other of the shafts to the axial reverse gear and to secondary teeth forming part of the axial forward gear;

¹ - control means for controlling the selection means. The invention thus provides a particularly simple combination to make and to control, in particular automatically. While the primary axial toothing is connected to a first of the shafts, for example the input shaft, the secondary and reverse gears constitute towards the other shaft, for example the output shaft, parallel paths whose l one of the choices is selectively activated by the selection means.

The selection means therefore exercise a function of mechanical switches each associated with one of several parallel power transmission channels.

Preferably, the axial forward gear teeth are planetary wheels and the axial reverse gear is a crown. This results in a particularly economical and compact embodiment. The satellite ordinarily comprises three or even four successive toothing stages, but this is not a drawback since there is anyway an axial length required for the selection means which are preferably produced with multi-disc clutches.

The invention also has the advantage of minimizing the losses due to the efficiency of the energy transfer through the mesh points. In particular, in the basic structure making it possible to carry out, as will be seen, at least four reports with a four-stage satellite, no report requires more than two meshing relationships between the input shaft and the tree Release. This result is to be compared with those of automatic transmissions with successive planetary trains, in which there are at least two meshing relationships in each planetary train not operating in direct drive. Each axial forward gear makes it possible to produce at least one respective forward transmission ratio without rotation of the planet carrier, but simply by rotation of the at least one satellite around its own axis. Thus, the friction losses, the operating noise, the wear, the angular momentum of the transmission device in operation, and the angular momentum variations during gear changes, are reduced. Reverse operation is also possible without rotation of the planet carrier, the at least one satellite simply serving as a direction of rotation reverser, with gear reduction, between the at least one primary toothing and the reverse gear. It is therefore possible to make the satellite carrier so that it is fixed to the transmission housing. If the transmission device comprises a direct connection by which the primary toothing is connected to both the input shaft and the output shaft independently of the differential mechanism, the satellite is then unnecessarily driven in reverse rotation, without transmitting power.

It is also possible, as a variant, that the selection means comprise release means to selectively allow axial rotation of the satellite carrier. These release means may include a free wheel which prevents reverse rotation of the planet carrier when the differential mechanism operates as a reduction between the primary toothing and one of the secondary teeth, and which allows the planet carrier to rotate at the same speed. than the primary teeth and the input and output shafts during direct drive operation.

Mechanically in parallel with this freewheel, it is appropriate to provide a brake to block the planet carrier when it undesirably tends to turn in the direct direction. This can occur in two cases, on the one hand during the transmission of an engine torque for the operation in reverse of the vehicle and on the other hand when the input torque is negative (operation in restraint). A third possible case is that in which at least one of the transmission ratios defined by the differential mechanism is an overdrive ratio (speed of the output shaft greater than the speed of the input shaft).

Each secondary toothing can work to define at least two different transmission ratios. There are many possibilities for this. In a preferred version, the connection means comprise a gear change mechanism, for example two-speed. Another possibility consists in providing a substitute axial toothing constituting a second primary toothing. The connecting means selectively connect the first shaft with the primary toothing or with the replacement toothing which meshes with a respective stage of the satellite.

Yet another possibility is to selectively block the axial reverse gear.

It would also be possible to place a gear change mechanism with at least two ratios between the secondary teeth and said other shaft, typically the output shaft, of the transmission device. In a preferred configuration, said first tree is the input tree; the multiplicative difference between two different ratios created by change of state of the connecting means corresponds to the desired multiplicative difference between two successive ratios of the transmission device and to the square root of the multiplicative difference between the successive ratios defined by the choice of the forward axial toothing which is connected to the second shaft.

The operation of such a transmission device is then as follows: for the lowest ratio (first speed) the connection means are in a first state and the secondary toothing which is activated is that which meshes with the stage of the satellite having the smallest diameter. Then the connecting means pass into their second state to produce the second transmission report. For the transition to the third gear, the connecting means return to their first state and the secondary toothing meshing with the second smallest diameter of the stage satellite is activated. For the fourth report, the connecting means pass to their second state, and so on.

Such a transmission device can be automated according to a modified "ANTONOV" principle: - for the connection means, if these consist of a reduction gear whose first state corresponds to reduction operation and the second state corresponds to direct drive operation, the "ANTONOV" principle as recalled above can be implemented without fundamental change;

- for the differential mechanism, a change is necessary insofar as the operation of a secondary toothing under load must maintain in the uncoupled state, not a clutch associated with this toothing, but a clutch or other associated coupling means at least one other secondary toothing;

- According to an advantageous feature, the primary teeth can be connected directly to the output shaft by a selective coupling means called "transfer", and the operation under load of the primary teeth transmitting a driving torque to the The corresponding stage of the satellite produces an axial toothing thrust which is used to maintain the selective transfer coupling device in the uncoupled state.

Automatic operation can then be as follows, in an example of a six-speed transmission:

- for the first transmission ratio: the axial teeth forces maintain all the coupling devices in the uncoupled state except that connecting the secondary teeth with the output shaft meshing with the stage of smaller diameter;

- the speed of rotation increasing, the centrifugal device sensitive to the output speed of the two-speed mechanism causes the passage of the latter in direct engagement (second gear of the transmission device);

- the speed continuing to increase, a centrifugal device sensitive to the speed of the output shaft, activates the following secondary toothing. Given the large multiplicative difference between two successive secondary teeth, this results in a sharp drop in the speed of rotation of the input shaft and therefore in the two-speed mechanism. Centrifugal force generated in the two-gear mechanism no longer makes it possible to transmit the torque and consequently the two-speed mechanism returns to operating as a reduction gear, which achieves the third gear of the transmission device;

- the speed continuing to increase, the two-speed mechanism returns to direct gear, which achieves the fourth transmission ratio;

- We can then arrive at a situation where the selective transfer coupling device goes into the coupled state under the effect of a centrifugal device associated with it. As a result, the engine torque is transmitted directly from the primary teeth to the output shaft, without going through the engagement relationships in the differential mechanism. The axial thrust of the primary toothing therefore disappears, and consequently ceases to contest the closure of the selective transfer coupling device. Furthermore, the new situation corresponds to a sharp reduction in the transmission ratio, to the point that the connection means return to their operation as a reduction gear. This is the fifth report (connecting means operating as a reduction gear, differential mechanism operating as a direct drive);

- Finally, the sixth report is established when the connecting means in turn pass directly, thus defining a sixth report.

We will see other possible operating modes in the description of the examples.

Other features and advantages of the invention, concerning in particular the practical and compact arrangement of the transmission device will appear from the description of the nonlimiting examples which will follow.

In the accompanying drawings:

- Figure 1 is a schematic half-view in axial section of a first embodiment of the transmission device according to the invention, with cutaway; - Figure 2 is a detail view of an alternative embodiment of the reverse gear of Figures 1 and 3 to 7;

- Figure 3 is a view similar to Figure 1 but relating to a second embodiment; - Figure 4 is a view similar to the right part of Figure 3 but relating to a modified embodiment;

- Figure 5 is a view similar to the upper right of Figure 3 in yet another modified embodiment; and

- Figures 6 and 7 are views similar to Figure 3 but relating to two other embodiments of the invention.

In the example shown, only schematically, in Figure 1, the transmission device comprises a housing 1 which is shown in one piece but which. can be made of several elements fixed to each other to the extent necessary for its manufacture and the assembly of the components of the transmission device inside.

The casing 1 has two opposite openings 2, 3. An input shaft 4 and an output shaft 6 are supported in the openings 2 and

3, respectively, along a common geometric axis 7 by respective bearings 8, 9. The bearings 8 and 9 axially immobilize the shafts 4 and 6 relative to the casing 1.

In the following, we will call:

- “axial” a toothing or other element having the axis 7 as a geometric axis and / or axis of rotation,

- "axial rotation" a rotation around the axis 7, - "axial direction" a direction parallel to the axis 7,

- "rotation in the direct direction" a rotation, generally around the axis 7, in the same direction as the input shaft 4 (whose direction of rotation is generally imposed by a motor) and / or that the output shaft 6 (when the vehicle is moving forward). - "reverse rotation" a rotation in the opposite direction to the direct direction. - "transmission ratio" the ratio of the speed of rotation of a first member, to the speed of rotation of another member located mechanically closer to the output shaft; for example, a transmission ratio of 4: 1 means that said other member rotates 4 times slower than the first member;

- "multiplicative difference" the ratio between two transmission ratios; for example, the multiplicative difference between a 4: 1 transmission ratio and a 2: 1 transmission ratio is equal to (4: 1) / (2: 1) = 2. The input shaft 4 is connected to an axial primary planetary wheel 1 1, by connection means 1 2. In this embodiment, the connection means 1 2 comprise a transfer shaft 1 3 on which is fixed the primary planetary wheel 1 1, and a input clutch 1 5, of multi-disc type, selectively joining the transfer shaft 1 3 in rotation with the input shaft 4. The transfer shaft 1 3 extends along the geometric axis 7 to the interior of the casing 1 between the input shaft 4 and the output shaft 6. The input clutch 1 5 is controlled by an annular piston 1 4 having a face 1 6 bearing on a stack of discs 1 7 alternately connected in rotation with the input shaft 4 and with the transfer shaft 1 3. An opposite face 18 of the piston 1 4 delimits a hydraulic chamber 1 9 select ectively supplied with pressurized oil to tighten the clutch 1 5 or on the contrary purged of its pressurized oil to allow relative rotation between the shafts 4 and 1 3. In practice, the input shaft 4 is in rotation relationship permanent joint with the crankshaft of a motor vehicle engine and the input clutch 1 5 is controlled automatically or manually to allow the transfer shaft 1 3 to remain stationary when the vehicle is stopped then that the input shaft 4 is rotated by the engine operating at idle. For starting the vehicle, the hydraulic pressure in the chamber 1 9 is controlled to gradually tighten the discs 1 7 of the input clutch 1 5 and gradually bring the transfer shaft 1 3 to a speed of rotation equal to that of the input shaft 4.

The primary planetary wheel 1 1 is part of a differential mechanism 21 installed in the casing 1 and whose general axis is the common axis 7 of the input shafts 4, transfer 1 3, and output 6.

The differential mechanism 21 consists of a complex planetary gear comprising an axial planet carrier 22 which is rotatably supported in a bearing 36 mounted in a partition 37 belonging to the casing 1 and separating the input clutch 1 5 and the mechanism 21 . The planet carrier 22 can thus rotate around the common axis 7 with respect to the transfer shaft 1 3 and around it. The planet carrier 22 rigidly carries an eccentric pin 23 parallel to the common axis 7 but radially spaced therefrom. The pin 23 carries a stage satellite 24. From a theoretical point of view, a single pin 23 and a single stage satellite 24 are sufficient for the operation of the transmission device. In practice, there are typically provided three eccentric pins 23 angularly distributed around the common axis 7, and three identical stage satellites 24 each carried by one of the pins 23. Each stage satellite 24 comprises, in the example shown, four teeth stages 26, 27, 28, 29, coaxial and integral with each other, and which mesh respectively with a primary axial toothing 31 belonging to the primary planetary wheel 1 1, and with three secondary axial teeth 32, 33, 34 which are also planetary teeth. The primary toothing stage 26, meshing with the primary planetary wheel 1 1, is that which has the largest diameter and is closest to the input side of the transmission device and the planet carrier 22.

The teeth stages of the satellite 24 then succeed in order of decreasing diameter. First there is the third secondary stage 29 meshing with the third secondary axial toothing 34 which, as will be seen, makes it possible to produce the third transmission ratio, then the second secondary stage 28 meshing with the second axial toothing secondary 33 which make it possible to produce the second transmission ratio, and finally the first secondary stage 27 meshing with the first secondary axial toothing 32 making it possible to produce the first transmission ratio. The differential mechanism 21 also comprises an axial reverse gear 38 produced in the form of a ring meshing with the primary stage 26 of the satellite 24 on the radially outer side thereof, therefore on the other side of the satellite. 24 with respect to the planetary teeth 31 to 34. Apart from their engagement with the same stage satellite 24, and apart from the selective coupling means still to be described, the axial teeth 31 to 34 and 38, respectively primary, secondary and reverse gear can all rotate independently of each other around the common axis 7.

The primary axial toothing 31, each secondary axial toothing 32, 33, 34 and the output shaft 6 are each secured, respectively, to a secondary transfer rotor 39, to a first secondary rotor 41, to a second rotor secondary 42, a third secondary rotor 43 and an output rotor 46.

The output rotor 46, the secondary transfer rotor 44 and the third, second and first secondary rotors 43, 42, 41 are produced in the general form of axial bells arranged one inside the other in the order indicated going from the exterior to interior. The bottoms of the bells are on the outlet side between the free end of the pins 23 and an end wall 48 of the casing 1. The peripheral walls of the bells are directed axially towards the entry side. Thus the bells cover the satellites 24 by their side opposite to the planet carrier 22.

Each secondary rotor 39, 41, 42, 43 is connected, respectively, to the primary teeth 31, and to the secondary teeth 32 to 34 by an axial fastening member constituted, respectively, by the transfer shaft 1 3, and by concentric axial tubes 51, 52, 53 which surround the transfer shaft 1 3 and are in fitting relation mutual with relative freedom of rotation. The end of the transfer shaft 1 3 on the output side 54 is rotatably supported in a manner which is only schematically illustrated in a bearing 56 of the output rotor 46 or of the output shaft 6. Each secondary rotor 39, 41, 42 or 43 can be coupled in rotation with the output rotor 46 by respective selective coupling means 57, 58, 59, 61 each comprising a respective multi-disc clutch, namely a first clutch 62, a second clutch 63, a third clutch 64, and a transfer clutch 66. Each of these clutches comprises a stack of discs alternately integral with the peripheral wall 49 of the output rotor 46 and the corresponding secondary rotor 41, 42, 43, 39 respectively . However, the first and second selective coupling means 57 and 58 each further comprise a free wheel 67, 68 mounted between clutch and secondary rotor to allow the corresponding secondary rotor respectively to rotate slower, but not faster, than the discs associated clutch. As a result, the output rotor 46 can rotate faster than the first and / or the second secondary rotor 41 and / or 42 even when the clutches 62 and / or 63 are in the tightened state. Each stack of discs is formed between a respective retaining plate 69, 71, 72, 73 secured to the outlet rotor 46, and a respective movable clamping plate 74, 76, 77, 78, integral in rotation with the outlet rotor 46 but able to slide axially relative to the latter.

The transmission device also comprises a selective reverse gear coupling device 79 comprising a multi-disc clutch 81, the discs of which are alternately integral in rotation with the peripheral wall 49 of the rotor 46 and the reverse gear ring 38. L stack of disks of the clutch 81 is placed between a retaining plate 82 secured to the wall 49 at the end thereof facing the inlet, and the movable clamping plate 74 of the first selective coupling device 57. The movable plate 74, mounted between the two clutches 62 and 81, serves as a means of selecting the direction of travel with three positions, a position for clamping the clutch 62 for forward operation, a neutral position or none of the clutches 62 and 81 is tightened , and a position for clamping the clutch 81 for reverse operation. The clutches 81, 62, 63, 64, 66 are arranged radially inside the peripheral wall 49 of the output rotor 46 and around the differential mechanism 21.

The selective coupling devices 79, 57, 58, 59, 61 which have just been described are part of means for selecting the ratio defined by the transmission device and each form between the output rotor 46 and the secondary rotor which their corresponds respectively, namely the axial reverse gear 38 and the successive secondary rotors 41, 42, 43, 39, a selectively activated mechanical connection for transmitting the engine torque.

The aforementioned mechanical connection between the axial reverse gear 38 and the output rotor 46 is located beyond the axial end of the secondary rotors 39 and 41 to 43. The connection associated with each secondary rotor 41, 42 or 43 which is located inside at least one other secondary rotor 42, 43 and / or 39 is disposed axially beyond the end, facing the inlet side, of this "at least one" other secondary rotor 42, 43, 39. For this, the secondary transfer bell 39, closest to the outlet bell 46, is shorter axially, in the direction of the inlet, than the third outlet bell 43, which is itself axially shorter than the second bell 42, itself shorter than the first bell 41 which extends roughly around the axial reverse gear 38. The peripheral wall 49 of the outlet bell 46 extends axially towards the entrance the first secondary bell 41 and surrounds the entire differential mechanism 21. Each secondary rotor 39, 41, 42, 43 is axially integral with the axial toothing 31, 32, 33, 34 with which it is respectively associated and the assemblies thus formed can slide axially with respect to each other, with respect to the casing 1, and with respect to the output shaft 6. With regard to the primary toothing 31, this axial sliding is allowed by an axially sliding mounting of the transfer shaft 1 3, of which the planetary wheel 1 1 and the secondary rotor 39 are integral, in the bearing 83 of the partition 37 and in the bearing 56 of the shaft 6.

The second and third selective coupling means 58, 59 and the selective transfer coupling means 61, each comprise, for their control, a series of centrifugal weights 84, 86, 87 carried by the peripheral wall 49 of the outlet rotor 46 and therefore rotating around the axis 7 at the same speed as the output shaft 6. The weights 84, 86, 87 pivot relative to the output rotor 46 about respective tangential axes 88 and have an actuating spout 89 which is supported on the movable plate 76, 77, 78 of the respective clutch by means of an elastic compression means constituted by belleville washers 91 (see more particularly the selective coupling means 59). The assembly is such that the centrifugal force to which the weights 84, 86, 87 are subjected due to the rotation of the output shaft 6 causes the weights to pivot about their respective tangential axis 88 in the direction tending to compress d on the one hand the belleville washers 91 and on the other hand the stacks of discs of the respective clutches 63, 64, 66.

On the other hand, the teeth of the differential gear 21 are made helical and therefore generate axial forces proportional to the tangent of the helix angle and to the tangential force transmitted at each point of engagement. The direction of these forces is determined by the direction of inclination of the teeth. In accordance with the ANTONOV principle, these forces are used as a measure of the transmitted torque. For this reason, the secondary transfer rotor 39 is pressed axially against the movable plate 78 of the transfer clutch 66, in the direction of its release, by means of a stop. axial 92. The direction of inclination of the primary axial toothing 31 is such that when the latter transmits a driving torque from the transfer shaft 1 3 to stage 26 of the satellite 24, the resulting primary axial thrust PAP is oriented in the release direction of the transfer clutch 66, therefore to the left in FIG. 1.

The second secondary rotor 42 is supported axially by an axial stop 94 against the movable plate 77 of the third clutch 64, so as to tend to loosen it when the second secondary axial toothing 33 receives a circumferential driving force from the second stage secondary 28 of satellite 24.

In addition, the first secondary rotor 41 is supported axially by an axial stop 93 against the movable plate 76 of the second clutch 63, so as to tend to loosen it under the action of the PASI axial thrust arising in the first toothing secondary axial 32 when the latter receives a circumferential driving force from the first secondary stage 27 of the satellite 24.

The first secondary rotor 41 is still supported by an axial stop 96 against the second secondary rotor 42. The stop 96 is oriented in the same direction as the stops 93 and 94. Thus, the secondary axial thrust PASI also tends to loosen the third clutch 64 by means of the axial stop 96 pushing the second secondary rotor 42 itself pushing the movable plate 77 by the axial stop 94.

In the example shown, all the axial thrusts PAP in the primary teeth 31, PASI in the first secondary teeth and PAS ₂ in the second secondary teeth must be oriented in the same direction when the transmitted torque is driving. This means that the direction of inclination of the primary axial teeth 31 must be opposite to that of the secondary axial teeth 32 and 33 because the primary axial teeth transmit the motive force to the satellite 24 while the secondary axial teeth 32 and 33 receive it from the satellite 24. The third secondary toothing 34 can be a straight toothing or a helical toothing with inclination in one direction or the other because the axial thrust which it possibly generates is not used in this embodiment. If for reasons of operating silence this toothing is made helically, its axial thrust can be resumed by means (not shown) of axial support on a ring 97 fixed to the planet carrier 22 by supports 98 distributed between the satellites 24 around axis 7.

The movable plates 76, 77, 78 of the second and third clutches 63, 64 and the transfer clutch 66 can be controlled in the release direction by a respective actuator 104, 106, 99.

The planet carrier 22 is connected to the casing 1 by a freewheel 1 01 which allows the planet carrier 22 to rotate in the direct direction with respect to the casing 1 and prevents the satellite carrier 22 from rotating in reverse with respect to the casing 1 .

In parallel with the freewheel 1 01, there is between the planet carrier 22 and the casing 1 a brake 1 02 which is normally in the released state but which can be put into the tightening state by an actuator 1 03. On will now explain the operation of the transmission device of FIG. 1.

At rest, the second and third clutches 63, 64, as well as the transfer clutch 66 are in the clamped state by their respective belleville washers 91. This achieves a direct engagement situation in which the planet carrier 22, the satellites 24 and the axial reverse gear 38 are secured to the transfer shaft 1 3 and to the output shaft 6. This is done, automatically , a certain immobilization of the parked vehicle, either by coupling it to the vehicle engine by maintaining the input clutch 1 2 in the tight state, or by applying the brake 102 securing the planet carrier 22 with the housing 1. To start the vehicle, the input clutch 1 2 being released, the engine is put into operation (not shown) which causes the rotation of the input shaft 4. A manual or automatic actuator moves the movable plate 74 in the direction of tightening the first clutch 62 and then causing the progressive tightening of the input clutch 1 2. The transfer shaft 1 3 is gradually rotated to a speed equal to that of the shaft input 4 and transmits to the primary teeth 31 a force which tends to rotate the planet carrier 22 with the shaft 1 3 and / or to rotate the satellites 24 in reverse around their respective journal 23. As the shaft 6 tends to be immobilized in rotation because of the load represented by the vehicle, it is the operating mode corresponding to the lowest possible speed of rotation for the output rotor 46 which prevails, especially since only the first clutch 62 is energized uement by the movable plate 74, the other secondary clutches 63, 64, 66 being clamped only by the belleville washers 91.

Consequently, the rotational movement of the primary toothing 31 in the forward direction tends to produce an opposite rotation of the satellite 24 rolling in the opposite direction on the first secondary toothing 32 tending to be immobilized by the load. But the immobility of the first secondary toothing 32 would result in a reverse rotation of the planet carrier 22, which prevents the freewheel 110.

It therefore establishes an operation where the planet carrier 22 is immobilized by the freewheel 110 and where the satellite 24 driven in reverse rotation around its fixed journal 23, rotates in direct direction the first secondary axial toothing 32. That -this drives the output shaft 6 via the first secondary stator 41, the freewheel 67, the first clutch 62 and the output stator 46. The axial thrust PAP generated in the primary axial toothing 31 is transmitted to the movable plate 78 by the axial stop 92, which causes the release of the transfer clutch 66. At the same time, the PASI axial thrust generated in the first secondary axial toothing 32 similarly loosens the second clutch 63 via the axial stop 93 and the third clutch 64 via the axial stops 96 and 94.

When the output rotor 46 reaches a certain speed of rotation, the centrifugal force generated by the flyweights 84 of the second selective coupling device 58 overcomes the opposite axial thrust imparted to the movable plate 76 through the axial stop 93, and pushes the plate 76 in the direction of tightening of the second clutch 63. Torque begins to be transmitted by the second secondary stage 28 of the satellite 24 to the second secondary axial toothing 33, to the second secondary rotor 42, via the free wheel 68 and the second clutch 63 until the speed of rotation of the output shaft 6 exceeds that of the first secondary rotor 41, as allowed by the freewheel 67. At this stage, the first secondary axial toothing 32 is discharged, the axial toothing force PASI disappears, and therefore ceases to challenge the tightening applied to the clutch 63 by the flyweights 84. The tightening force defined by the flyweights 84 corresponds to a certain e capacity for transmitting torque through the stack of discs 63.

At the same time, an axial thrust PAS _{2 is} established in the second secondary toothing 33 which maintains the third clutch 64 in the uncoupled state by means of the axial stop 94. Furthermore, the thrust PAP generated by the toothing primary 31 continues to maintain the transfer clutch 66 in the released state.

If for example the speed of the output 6 decreases and / or the torque to be transmitted increases, the clamping force defined by the counterweights 84 may become insufficient to transmit the torque. The stack of discs 63 then starts to slip until the speed of the output rotor 46 becomes equal and even tends to become lower than the speed of the first secondary rotor 41, which is prevented by the free wheel 67. At this time, the first secondary axial toothing 32 begins to transmit torque again, the axial thrust PAS. recovers and loosens the second clutch 63, further reducing the torque transmission capacity thereof until it is completely released. The transmission device therefore automatically returned to its first gear operation. Returning to the operating situation in second gear, if the speed of output 6 continues to increase, a moment arrives when the flyweights 86 of the third clutch 64 cause the latter to couple and, by a process similar to that described for the passage from the first to the second gear, the engine torque is then transmitted by the satellite 24 and particularly by its third secondary stage 29 to the third secondary axial toothing 34 then by the third clutch 64 directly to the output rotor 46. The rotor 46 then rotates faster than the first and second secondary rotors 41, 42 but this is allowed by the freewheels 67 and 68. The axial thrust PAP generated in the primary axial toothing 31 continues to maintain the transfer clutch 66 in the state uncoupled.

From operation in third gear, there may be a return to operation in second gear if the second clutch 64 is not capable of transmitting the torque taking into account the tightening force generated by the flyweights 86, or on the contrary a passage in direct engagement if, the speed of the output shaft 6 increasing, the weights 87 are capable of tightening the transfer clutch 66 by overcoming the primary axial thrust (PAP) transmitted by the axial stop 92. The tightening of the clutch 66 engages directly between the transfer shaft 1 3 and the output shaft 6, independently of the differential gear 21, the teeth of which no longer transmit torque. As the third secondary rotor 43 is always integral with the output rotor 46, the entire differential mechanism 21 rotates in one piece with the transfer shaft 1 3, as the free wheel 101 allows. From direct drive operation, if the tightening provided by the flyweights 87 is no longer sufficient to transmit the engine torque, the transfer clutch 66 starts to slip, the speed of rotation of the planet carrier 22 decreases relative to the speed of the transfer shaft 1 3 then the planet carrier 22 eventually stops when the speed of rotation of the output rotor 46 becomes equal to that of the third secondary rotor 43. The operating conditions in third gear are restored.

When the motor is operating in restraint, the axial thrust PAP reverses (it therefore becomes directed to the right in the example in FIG. 1). The transfer clutch 66 is therefore tightened by the bellevilles washers 91 or by the centrifugal weights 87. This establishes direct drive operation.

By activating the actuators 99 and 1 03, it is possible simultaneously to release the transfer clutch 66 and immobilize the planet carrier 22 in the casing 1. Operating conditions are thus established in third gear. Under these conditions where the output shaft 6 becomes the drive shaft and the input shaft 4 becomes the resistive shaft, the planet carrier 22 tends to rotate in the direct direction but this is prevented by the brake 102.

For reverse operation, the movable plate 74 is actuated to its other extreme position corresponding to the tightening of the reverse clutch 81. The axial reverse gear 38 is thus secured to the output rotor 46. At the same time, the actuator 103 is activated to apply the brake 102 preventing rotation of the planet carrier 22, in particular in the direct direction.

In this case, the satellites 24 and in particular their primary stage

26 form a movement reverser between the planetary wheel 1 1 and the axial reverse gear 38. The actuators 104, 106, 99 maintain the second and third clutches 63, 64 and the transfer clutch 66 in the uncoupled state.

For starting the vehicle, instead of relying on the appearance of axial thrusts to decouple the second and third clutches 63, 64, and the transfer clutch 66, the actuators 99, 1 04 and 106 can be activated automatically. when a sensor (not shown) of the speed of rotation of the output shaft 6 detects a negative speed of rotation or even a positive speed of rotation but less than a value corresponding to for example 1 0km / hour for the vehicle. The actuators 99, 1 04 and 1 06 can also be used for various functions described in the prior documents of the same applicant, in particular for modifying the crossing points defined by the strictly automatic operation which has just been described, or even as shock absorber preventing the weights 84, 86, 87 from abruptly tightening a clutch, in particular when the axial thrust which kept this clutch in the released state suddenly disappears (when the driver of the vehicle abruptly releases the accelerator pedal).

In the example of FIG. 2, only the reverse gear is modified compared to FIG. 1. Instead of the movable plate 74 of FIG. 1, there is provided a dog clutch 274 integral in rotation with the peripheral wall 49 of the outlet rotor. A control means, not shown, makes it possible to axially move the dog clutch 274 from the neutral position shown, either in a position of engagement with a complementary dog clutch 262 coupled in axial rotation with the first secondary rotor 41 for operation in forward gear, either in the opposite direction, that is to the left of FIG. 2, in a position of engagement with a complementary dog 281 secured to the reverse gear 38 for operation in reverse.

The embodiment with six automatic speeds represented in FIG. 3 will only be described for its differences from that of FIG. 1.

In the example of FIG. 1, the second and third stages 28, 29 of the satellite, the second and third securing tubes 52, 53, the second and third secondary stators 42 can be described as “intermediaries”. 43, the second and the third secondary selective coupling means 58, 59, as well as the second and third associated secondary clutches 63, 64.

With regard to the differential mechanism 21 of the embodiment of FIG. 3, the modifications with respect to FIG. 1 are as follows: the satellite now only has two secondary stages, namely a first secondary stage 27 and a single stage intermediate secondary 228.

There is also only one intermediate secondary rotor 242 connected by a single securing tube 252 to a single intermediate secondary rotor 242, itself capable of being selectively connected to the output rotor 46 by a single coupling device. selective secondary intermediate 258 comprising a multi-disc clutch 263 without interposition of freewheel between the clutch and the intermediate secondary rotor 242. An actuator 304 acting on the movable plate 278 makes it possible to control the release of the clutch 263.

The first secondary rotor 41 no longer transmits its PASI axial thrust to an intermediate secondary rotor (in other words the stopper 96 is eliminated), but simply to the movable plate 276 of the intermediate clutch 263 via the stopper 293. The secondary axial thrust PASI originating in the intermediate secondary axial toothing 233 is not used for the automatic control of the transmission device, and can be supported by the ring 97 already described with reference to FIG. 1. The axial stop 94 of Figure 1 is therefore also deleted. Furthermore, the diameters of the stages 26, 27, 228 of the satellite 21 are chosen so that the multiplicative difference between two successive ratios defined by the mechanism 21 is equal to the square of the desired difference between two successive ratios desired for the assembly of the transmission device between the input shaft 4 and the output shaft 6. If for example, according to a conventional configuration, the difference between two successive transmission ratios is desired to be equal to approximately 1.41 (c ' is to say -y / 2), the multiplicative difference created by the tightening of the secondary clutch 263 is typically equal to 2 (namely 1, 41 ² ) and the same goes for the multiplicative difference then created by tightening the transfer clutch 66. FIG. 3 shows that in order to achieve these relatively large multiplicative differences, the differences in diameter between successive stages 26, 28, 27 of the satellite 21 are greater than in FIG. 1.

The other important difference with the embodiment of FIG. 1 relates to the means of connection between the input shaft 4 and the primary planetary wheel 1 1. The receiving member of the input clutch 1 5, instead of being integral with the transfer shaft 1 3, is now constituted by a connecting shaft 21 3 driving in rotation an input member 107 of a primary mechanism 108 capable of producing one or the other of two transmission ratios. The mechanism 108 interposed between the connecting shaft 21 3 and the transfer shaft 1 3, comprises a primary gear in the form of a planetary gear whose crown 109 is rigidly connected to the input member 1 07. The planetary wheel 1 1 1 of the planetary gear is connected to the casing 1 by a free wheel 1 1 2 mounted mechanically in parallel with a brake 1 1 3 which can be selectively activated by means of an actuator 1 14. Satellites 1 1 6 meshing both with the planetary wheel 1 1 1 and with the crown 1 09 are supported in rotation by a planet carrier 1 1 7. A cage 1 1 8 is supported in axial rotation, and immobilized in axial translation in the casing 1 thanks to a bearing 1 1 9. The cage 1 1 8 is linked in axial rotation with the transfer shaft 1 3 by means of grooves 1 21 which allow the axial sliding of the transfer shaft 1 3 for actuating the plate mobile 78 of the transfer clutch 66 as explained in ref erence in Figure 1. Furthermore, the cage 1 1 8 is linked in axial rotation with the satellite carrier 1 1 7 by means of internal grooves 1 26 in which is engaged a peripheral toothing 1 25 of the satellite carrier 1 1 7. The satellite carrier 1 1 7 can thus slide axially relative to the cage 1 1 8. The mechanism 108 is capable of direct engagement operation by tightening a direct engagement clutch 122 connecting in rotation the input member 107 with the cage 118. The clutch 122 comprises a stack of discs 123 which are alternately linked in rotation with the input member 107 by means of grooves 124 formed at the outer periphery of the crown 109, and with the cage 118 by means of the grooves 126 formed at the inner periphery thereof. For direct drive operation, the stack 123 can be clamped axially between a retaining plate 127 secured to the cage 118 and a movable plate 128 secured to the planet carrier 117. The cage 118 carries centrifugal weights 129 which therefore rotate at the same axial rotation speed as the cage 118. The counterweights 129 can pivot relative to the cage 118 along a respective tangential axis 131 to more or less urge the movable plate 128 in the direction of tightening of the stack 123 by the intermediate Belleville type compression springs 132. The teeth of the change mechanism 108 are helical. Also, when these teeth operate under load to transmit a driving torque from the input member 107 to the cage 118, the crown 109 undergoes an axial thrust PAC. This axial thrust PAC is transmitted to the planet carrier 117 by an axial stop 133 in the direction of release of the clutch 122 against the clamping forces produced by the counterweights 129 and / or the springs 132. Another axial stop 134 is mounted between the pressing member 136 of the brake 113 and the planet carrier 117 so that the application of the brake 113 is accompanied by a release of the clutch 122.

We will now describe the operation of the two-speed mechanism 108. For starting the vehicle, the actuator 114 is activated to apply the brake 113 and release the clutch 122 until the vehicle has, for example, reached a speed of 10 km. /hour. Under these conditions, the load represented by the vehicle tends to immobilize the cage 118 by means of the differential mechanism 21 which is assumed to be functioning according to its first report. This tendency to the immobility of the cage 1 1 8 and therefore of the satellite carrier 1 1 7 means that the satellites 1 1 6 tend to behave as motion inverters. Consequently, the planetary wheel 1 1 1 tends to rotate in reverse, but this is prevented by both the freewheel 1 1 2 and the brake 1 1 3. Consequently, the satellites 1 1 6 roll on the planetary wheel 1 1 1 immobilized. This causes the planet carrier 1 1 7 to rotate axially in the same direction as the input member 1 07 but at a reduced speed relative thereto. The actuator 1 14 is then released but the axial thrust PAC maintains the clutch 1 22 in the released state. However, as the speed increases, there comes a time when the weights 1 29 are capable of tightening the clutch 1 22 against the axial force PAC. Part of the torque begins to be transmitted through the clutch 1 22, consequently the axial force PAC decreases and the tightening process of the clutch 1 22 accelerates until the direct engagement is carried out.

If for example the speed of rotation of the cage 1 1 8 decreases and / or the torque to be transmitted increases, it may happen that the tightening applied by the weights 1 29 is no longer sufficient to transmit the torque. The clutch 1 22 then starts to slip, the planet carrier 1 1 7 slows down relative to the crown 1 09, and consequently the planetary wheel slows down even faster until being immobilized by the freewheel 1 1 2. This causes the PAC thrust to reappear which urges the movable plate 1 28 in the direction of release of the clutch. The reducer operation initially described is restored. The multiplicative difference between the transmission ratios produced when the mechanism 108 is in the reducing state and in the direct setting state is approximately equal to the square root of the multiplicative difference between two successive ratios defined by the mechanism 21. We have seen that this multiplicative difference was equal to 2 in mechanism 21, so it is approximately equal to 1.4 in mechanism 108. We will now describe the overall operation of the transmission device of FIG. 3.

For the first transmission ratio, the mechanism 1 08 operates as a reduction gear (ratio 1, 4: 1) and the differential mechanism 21 operates on its lowest ratio corresponding to a reduction of for example 4: 1. The total ratio is therefore typically 1.4 × 4 = 5.6: 1. Just before switching to the second gear, for a given torque to be transmitted and the input shaft 4 rotating at for example 5600 revolutions per minute, the cage 1 1 8 and the transfer shaft 1 3 rotate at 5600/1, 4 = 4000 rpm and the output shaft 6 rotates at 4000/4 = 1000 rpm. The speed of rotation of the cage 1 1 8 is therefore at this stage much higher than that of the output rotor 46. The weights 1 29 of the mechanism 1 08 are raised before any significant lifting of the weights 286 and 87 and the mechanism 1 08 goes into direct drive. This achieves the second transmission ratio [ratio (1: 1) x (4: 1) = 4: 1]. The speed of the output shaft 6 remains unchanged because imposed by the speed of the vehicle. It is therefore the speed of the input shaft 4 which drops to 4000 revolutions / minute, that is to say the speed of the transfer shaft 1 3. The speed of the vehicle being supposed to continue to increase, it happens a moment, for example when the output rotor 46 reaches the speed of 1,400 revolutions / minute, when the flyweights 286 of the intermediate secondary clutch 263 rise and cause this clutch to be tightened. The differential mechanism 21 therefore begins to operate according to its second intrinsic ratio which is 2: 1. This causes a corresponding decrease in the speed of rotation of the input shaft 4 from 5600 to 2800 rpm. This speed is no longer sufficient for the clutch 1 29 to be able to transmit the engine torque in direct engagement in the mechanism 1 08. This therefore returns to the reduction gear operation by slipping of the clutch 1 22 until immobilization of the planetary wheel 1 1 1 by the freewheel 1 1 2 and, consequently, reestablishment of the axial thrust PAC coming to push back the movable plate 1 28 and fold down the weights 1 29. The speed of rotation of the input shaft 4 therefore goes back to 2800 x 1, 4 = about 4000 revolutions / minute. This is the third gear ratio [(1: 4: 1) x (2: 1) = 2.8: 1].

Then, the speed of rotation of the input shaft 4 goes up to 5600 revolutions / minute, speed for which the weights 1 29 of the mechanism 1 08 rise again and cause the mechanism 1 08 to go back in direct drive operation to achieve the fourth transmission ratio [(1: 1) x (2: 1) = 2: 1] for which, just after the change, the speed of rotation of the input shaft 4 is 4000 revolutions / minute and that of the output rotor 46 of 2000 revolutions per minute.

As the speed continues to increase on the output shaft 6, the output rotor 46 reaches a speed of approximately 2800 revolutions per minute where the weights 87 cause the transfer clutch 66 to go into the tightened state. rotation of the cage 1 1 8 therefore becomes equal to that of the output shaft 6, i.e. 2800 revolutions / minute and the same applies to the input shaft 4 since the change mechanism 1 08 was in engagement direct. But, as we have already seen for the passage from the second to the third gear, this speed is too low for the mechanism 108 to continue to operate in direct drive, it therefore switches back to the reduction gear operation, causing the speed to increase. shaft rotation 4 to 4000 rpm. This achieves the fifth transmission ratio [(1: 4: 1) x (1: 1) = 1 _,: 1].

The speed of rotation of the output shaft 6 continuing to increase, the weights 1 29 will tighten the clutch 1 22 a third time when the speed of rotation of the cage 1 1 8 (and consequently that of the shaft 6 ) reaches 4000 rpm. This will produce the sixth transmission report, constituting a general direct connection of the transmission device.

For restrained operation, all centrifugal devices tend to tighten the corresponding clutches and therefore the device naturally tends to operate in direct drive. of the combinations of commands selectively applied to actuators 99, 1 03 and 1 1 4 make it possible to selectively operate the transmission device according to any one of the third to fifth ratios:

- for operation according to the fifth report, it suffices to activate the actuator 1 14.

- for the operation according to the fourth report, it is necessary to deactivate the actuator 1 1 4 to allow the direct engagement of the mechanism 1 08, and activate the actuators 99 and 1 03 to immobilize the planet carrier 22 while activating the toothing secondary secondary sun gear 233 for the transmission of torque in mechanism 21.

- For operation according to the third report, it is necessary to maintain the activations of the actuators 99 and 1 03 and also activate the actuator 1 14 to operate the mechanism 1 08 as a reduction gear. This embodiment, as we have seen, requires for the transition from the second to the third gear and from the fourth to the fifth gear, a simultaneous or almost simultaneous change of state in two clutches. We have also seen that this change of state can be spontaneous, that is to say controlled only by the balance between the different centrifugal forces and teeth forces brought into play in accordance with the "ANTONOV" principle. However, reference will be made to WO-A- / 97 08478 and 99 1 3247 as regards the means for improving the synchronization of such double changes of state in an ANTONOV type transmission. The example of FIG. 4 will only be described for its differences from that of FIG. 3. In this embodiment, the planet carrier 222 is integral with the casing 1, so that the partition 37 is no longer necessary. The freewheel 1 01 and the brake 1 02 as well as its actuator 103 are also eliminated. Thus, the construction is significantly simplified. On the other hand, the planet carrier 222 can no longer rotate in one piece with the transfer shaft 1 3 and the output shaft 6 during the direct drive operation. This operation, when the transfer clutch 61 is in the tight state, will therefore cause a reverse rotation of the satellite 24 around its pin 23 (as well as a reverse rotation of the reverse gear 38). The reverse rotation of the satellite 24 at a determined speed around a fixed journal 23 causes the first secondary rotor 41 and the intermediate secondary rotor 242 to rotate at different speeds from one another and less than the common speed of rotation of the secondary transfer rotor 39 and of the output rotor 46. With regard to the first secondary rotor 41, such rotation is permitted by the free wheel 67. On the other hand, to allow the aforementioned rotation of the intermediate secondary rotor 242, we have interposed a free wheel 268 between the clutch 63 and the intermediate secondary rotor 242.

In addition, an additional clutch 137 has been installed between the output rotor 46 and the intermediate secondary rotor 242, in parallel with the assembly constituted by the clutch 263 and the freewheel 268. This additional clutch is controlled by an actuator 1 00 to put the clutch 1 37 in the tightened state. The actuator 100 at the same time puts the transfer clutch 66 in the released state. This ensures the operation of the transmission device retained according to the third and fourth reports. In particular, the tightening of the clutch 13 is equivalent to neutralizing the freewheel 268 which would otherwise allow the output rotor 46 to rotate faster than the intermediate secondary rotor 242 even if the clutch 263 was tightened.

For starting the vehicle up to a speed of 10 km / h, the actuators 99 and 304 are activated and the actuator 1 00 is deactivated, the actuator 99 having the function of releasing the transfer clutch 66 without tightening clutch 1 37.

In the example shown in Figure 5, which will only be described for its differences from that of Figure 3, the transfer shaft 1 3 and the planetary wheel 1 1 can be immobilized axially and the support ring 97 can be deleted. The clutch release action transfer 66 is ensured by an axial stop 292 transmitting to the movable plate 78 via the intermediate secondary rotor 242 the PASI axial thrust originating in the intermediate secondary axial toothing 233 of FIG. 3. The axial stop 92 of FIG. 3 is deleted. For the release of the transfer clutch 66 when the mechanism 21 operates according to its first transmission ratio, one could have provided an axial stop such as the stop 96 of FIG. 1 between the first and the second secondary rotor 41 and 42. As a variant making it possible to remove an axial stop, a traction link 13 is provided between the movable plate 276 of the intermediate clutch 263 and the movable plate 78 of the transfer clutch 66, so that the movable plate 78 is necessarily in the release position when the plate 276 is in the release position. This eliminates an axial stop, as well as the noise and the corresponding risks of wear. FIG. 5 illustrates that the link 1 38 cannot operate in thrust, so that maintaining the plate 78 in the loosening position does not loosen the plate 276.

To simplify the presentation of FIG. 5, the actuators for the restrained operation have not been shown. The embodiment of FIG. 6 will only be described for its differences from that of FIG. 4, that is to say with the planet carrier 222 secured to the casing 1. We find on the satellite 24 the primary toothing stage 26 meshing with the primary axial toothing 31, a first secondary toothing stage 27 meshing with a first secondary axial toothing 32, and an intermediate toothing stage 228 meshing with a secondary axial toothing intermediate 233. The arrangement of the selective coupling reverse gear 79, forward gear and first gear 57, intermediate gear 258 with operating clutch retained 1 37, and transfer 61 is the same as at Figure 4 with the following exception: to act on the movable plate 78 of the transfer clutch 66 in the direction of loosening with a force proportional to the torque to be transmitted, the axial stop 92 is eliminated, and replaced by an axial stop 292 (similar to that of FIG. 5) between the intermediate secondary rotor 242 and the movable plate 78, as well as by a stop axial 296 (analogous to the axial stop 96 of FIG. 1), between the first secondary rotor 41 and the intermediate secondary rotor 242.

The satellite 24 further comprises, between the primary stage 26 and the planet carrier 222, a substitute stage 1 39 whose diameter is intermediate between that of the primary stage 26 and that of the intermediate secondary stage 228. The primary stage 26 is placed axially between the secondary stages 27 and 228 on one side, and the substitute stage 1 39 on the other. Typically, the diameters of the primary 26 and secondary 27 and 228 stages of the satellite 24, and the diameters of the corresponding axial teeth 31, 32, 233, can be the same as in the example of FIGS. 3 to 5.

The substitute stage 139 meshes with a primary substitute axial toothing 1 41 belonging to a substitute planetary wheel 142 secured to a substitute primary rotor 1 43 supported in rotation in the casing 1 and more particularly in a bearing 144 mounted in the satellite carrier fixed 222. The substitute planetary wheel 1 42 and the substitute rotor 1 43 are immobilized axially relative to the casing 1.

Furthermore, the connecting means also comprise a primary rotor 144 secured to the transfer shaft 1 3, and a common rotor 146 secured to the connecting shaft 21 3 which corresponds to the driven shaft of the clutch input 1 2 not shown in Figure 6.

The common rotor 146 and the connecting shaft 21 3 are selectively linked in rotation with the primary rotor 144 or with the substitute rotor 143 by primary selective coupling means 1 47 comprising:

- between the connecting shaft 21 3 and the primary rotor 1 44, a free wheel 1 48 requiring the transfer shaft 1 3 to rotate at least as fast, in the direct direction, as the connecting shaft 21 3 . - A primary cage 1 61 integral in rotation with the connecting shaft 21 3 but able to slide axially relative to the latter by virtue of teeth 1 59 formed at the periphery of the common rotor 1 46, engaged in radially internal grooves 1 60 of cage 1 61. - Between the cage 1 61 and the substitute rotor 143, a clutch 149 comprising, between a fixed plate 1 51 secured to the substitute rotor 143 and a movable plate 1 52 secured to the cage 1 61, a stack of disks alternately linked in rotation to the rotor 1 43 and cage 1 61. The clutch 1 49 can be axially tightened by centrifugal weights 1 53 driven in axial rotation by the substitute rotor 143 and acting by means of belleville springs 1 54 and an axial stop 1 56 on the movable plate 1 52.

- A retaining operating clutch 1 57 mechanically mounted in parallel with the free wheel 1 48 between the common rotor 1 46 and the primary rotor 1 44, this clutch having a movable plate 1 63 secured to the cage 1 61.

- mutual axial bearing surfaces 1 58 between the primary rotor 144 and the cage 1 61, so that the primary rotor 1 44 can move axially under the action of the axial thrust PA _P in the primary toothing 31 until at a position corresponding to the release of the clutch 149 then to the tightening of the clutch 1 57.

- An actuator 1 62 acting selectively on the primary cage 1 61 in the direction of the release of the clutch 1 49 and the tightening of the operating clutch in retention 1 57. We will now describe the operation of the embodiment of the Figure 6. When starting the vehicle, the actuator 1 62 is activated as well as the actuators 99 and 304 intended to put in the uncoupled state respectively the primary clutch 149, as well as the intermediate secondary clutches 263 and transfer 66. By Consequently, the torque is transmitted from the connecting shaft 21 3 to the transfer shaft 1 3 by the freewheel 1 48, and redundantly by the retaining clutch 1 57. The satellite 24, driven in rotation on itself by meshing with the planetary wheel 1 1, in turn drives the output rotor 46 via the first secondary rotor 41 and the first secondary clutch 62. The axial thrust PA keeps the cage 1 61 in the position corresponding to the release of the clutch 1 49.

During this time, the substitute rotor 1 43 undergoes an axial rotation at a speed which is divided by approximately 1, 4 (for example) with respect to the speed of the intermediate shaft 21 3 and of the transfer shaft 1 3. This division results from the value of the diameter of the substitute stage 1 39 compared to that of the primary stage 26 on the satellite 24. The output shaft 6 rotates at a speed divided by 4 compared to that of the connecting shaft 21 3 (motor speed).

The axial thrust PSAI in the first secondary axial toothing 32 is transmitted by the axial stop 293 to the movable plate 276 of the intermediate secondary clutch 263 in the direction of release of the latter, and by the axial stops 296 and 292 to the movable plate 78 in the direction of release of the transfer clutch 66.

When the speed of rotation of the connecting shaft 21 3 reaches a certain threshold which is all the higher the higher the torque to be transmitted, say for example 5600 revolutions per minute (speed of the shaft output 6: 1,400 rpm), the counterweights 1 53 move the cage 1 61 in the direction (to the right of FIG. 6) causing the clutch 1 49 to be tightened against the thrust PAP, and consequently the connection of the connecting shaft 21 3 with the substitute rotor 143. At the same time, this displacement of the cage 1 61 causes the clutch 1 57 to be released.

The tightening of the clutch 1 49 secures the substitute rotor 143 with the connecting shaft 21 3, the speed of which therefore drops from 5600 to 4000 revolutions per minute. The overall transmission ratio increased from 4: 1 (first gear) to 2.8: 1 (second gear). The transfer shaft 1 3 continues to turn at 5600 rpm, hence now faster than the connecting shaft 21 3, but this is allowed by the freewheel 148.

The speed of rotation of the output shaft 6 increases for example from 1,400 to 2,000 revolutions per minute and the weights 286 of the intermediate secondary clutch 263 are raised and cause this clutch to be tightened, therefore activating the intermediate secondary rotor 242 for transmitting the torque in place of the first secondary rotor 41. The overall transmission ratio therefore drops from 2.8: 1 to about 1.4: 1, so that the speed of rotation of the connecting shaft 21 3 drops to 2800 revolutions per minute, a speed which is insufficient to maintain in the clutch 1 49 sufficient tightening to transmit the torque. The clutch 149 starts to slip until the speed of the transfer shaft 1 3 becomes equal to the speed of the connecting shaft 21 3 and the torque transmission function of the free wheel 1 48 resumes. This brings back the axial thrust PAP from the primary axial toothing 31. The primary rotor 144 is pushed to the left in FIG. 6 and by the mutual support of the surfaces 1 58, the movable plate 1 52 is itself pushed to the left, that is to say in the direction of loosening of the clutch 1 49. Consequently, the transmission takes place from the transfer shaft 1 3 via the primary axial toothing 31, the primary stage 26 of the satellite 24, the intermediate secondary stage 228 of the satellite and the intermediate secondary axial toothing 233 to the intermediate secondary rotor 242, which corresponds to a reduction ratio of 2: 1 (third gear), therefore at a speed of approximately 4000 revolutions per minute for the connecting shaft 21 3.

The speed of the connecting shaft 21 3 increases to about 5600 revolutions per minute, the clutch 1 49 tightens again, therefore the torque starts again to be transmitted via the substitute rotor 1 43, the substitute axial teeth 1 41 and the substitute stage 1 39 then, as for the previous report, by the intermediate secondary stage 228 and the intermediate secondary axial toothing 233. This path corresponds to a ratio approximately equal to 1.4: 1 (fourth ratio).

Then, the speed of the output shaft 6 reaches about 4000 rpm, the transfer clutch 66 passes in the coupled state and this causes a process similar to that already described for the transition from ^2nd to ^3rd report , namely due to an insufficient speed of the connecting shaft 21 3, a decoupling of the clutch 149 and consequently the reactivation of the freewheel 148 to transmit the movement of the connecting shaft 21 3 to the 'transfer shaft 1 3. This corresponds to a direct drive in the entire transmission for the fifth report thereof.

The speed of rotation of the output 6 continuing to increase, the clutch 1 49 changes again to the coupled state and the movement is now transmitted from the substitute rotor 1 43 to the substitute axial teeth 1 41, on the stage substitute 1 39, at the primary stage 1 26 and from there to the transfer shaft 1 3 then, by the transfer clutch 66, to the output shaft 6.

In this situation, the mechanism 21 operates as an overdrive with a transmission ratio of approximately 0.7: 1. The primary axial toothing 31 then operates as a torque receiver, so that its axial thrust is now oriented in the direction opposite to the thrust PAP shown in FIG. 6, so it will not tend to loosen the clutch 1 49.

This overdrive operation tends to rotate the planet carrier 222 in the forward direction. Consequently, if the planet carrier was not fixed to the casing 1, the operation would only be possible by activating a brake analogous to the brake 1 02 in FIG. 3 during this phase of operation.

For restrained operation, appropriate commands must be applied to actuators 1 00, 304 and 1 62 if one wishes to switch from spontaneous operation with an overdrive to a functioning according to one chosen from the third, fourth and fifth transmission ratios.

The example of FIG. 7 will only be described for its differences from that of FIG. 6, namely: - the substitute stage 1 39 of the satellite 24 now has a larger diameter than the primary stage 26;

- The planet carrier 22 is now arranged as in FIG. 3, that is to say with the possibility of turning in the direct direction thanks to a free wheel 1 01 preventing reverse rotation, and of being prevented from turning in the direct direction thanks a brake 1 02 subjected to the action of an actuator 1 03;

- the reverse gear 38 meshes with the first secondary stage 27 of the satellite 24;

- A brake 1 66 controlled by an actuator 1 67 allows to immobilize the crown 38; - the free wheel 348 and the brake 367 are now installed between the cage 361 movable in rotation with the connecting shaft 213 and the substitute rotor 1 43 to impose on the substitute rotor 143 a rotation speed at least equal, in the direct direction , to that of the connecting shaft 21 3; - The weights 1 53 are still rotated by the substitute rotor 1 43 but they now tend to tighten a clutch 349 for selective connection between the common rotor 1 46 and the primary rotor 144 secured to the transfer shaft 1 3 as before ;

the planetary substitute wheel 142 is linked to the substitute rotor 143 no longer directly but via splines 1 68, so that the axial thrust PASU originating in the planetary substitute wheel 1 42 when it transmits a driving torque to the satellite 24 may, by mutual bearing surfaces 358 with the cage 361, pull the cage 361 in a direction (to the right of FIG. 7) corresponding to the release of the clutch 349. In operation, six reports follow one another in a manner analogous to that described with reference to FIG. 6, except that among the two successive reports corresponding to each combination of states of the secondary clutches 62, 263, 66, the lowest report corresponds to the transmission of the torque to the substitute planetary wheel 142 via the free wheel 348 then, for the next gear, when the clutch 349 is tightened, the torque is sent to the transfer shaft 1 3 and reaches to satellite 24 via the primary stage 26. The last gear corresponds to a direct connection from the connecting shaft 21 3 to the transfer shaft 1 3 by the primary clutch 349, then to the output shaft 6 by the transfer clutch 66. There is therefore no overdrive.

This transmission device however offers an additional report by blocking the crown 38 by means of the brake 1 66. At the same time as the brake 1 66, the commissioning of the additional report requires the activation of the actuators 99, 1 04 and 1 62 so that the engine torque is introduced into the satellite 24 by the substitute planetary wheel 142 and is collected by the first secondary rotor 41. The transmission ratio thus obtained is typically about 1.15: 1, so it is inserted between the fifth and the last gear in the series of six normal gears. This additional gear can for example be activated automatically when the driver presses the accelerator pedal fully while the speed of the output shaft 6 is higher than the speed range corresponding to the fifth gear. For reverse gear, the brake 1 66 being released, the brake is activated

1 03 and the clutch 79 as in the other embodiments. It is also possible to provide an actuator (not shown) for tightening the clutch 349 so that the movement is transmitted to the satellite 24 via the primary axial toothing 31. This may, depending on the case, make it possible to carry out a reverse gear ratio. better suited than if the engine torque were introduced via the replacement stage 1 39.

Of course, the invention is not limited to the examples described and shown. In the example shown in Figure 1, the planet carrier 22 could also be rotatably supported on the transfer shaft 1 3, or alternatively, instead of being mounted in the partition 37, the bearing 83 supporting the transfer shaft 1 3 on the input side could be mounted in the satellite carrier 22. In the embodiments of FIGS. 1, 3 and 4, one could mount on the ring 97 a bearing supporting the secondary axial toothing 33 in the axially immobilizing, as well as the associated secondary rotor 43.

The additional report by blocking the reverse gear as 38 described with reference to Figure 7 can be transposed to the other examples.

The satellites are not necessarily arranged on one side of the planet carrier. For example, in FIG. 7, where the ring gear 38 does not mesh with the stage situated furthest to the left, the satellite carrier could hold the satellite 24 between stages 26 and 228. The satellite carrier can also be produced in the form of a cage holding the pins 23 by their two ends. Other arrangements are also possible.

In the various embodiments, we have not shown or described all the means necessary in practice, but conventional in themselves, for axially retaining the shafts and rotors under the action of thrusts which are not used for the control means of selection. For example, in FIG. 1, the means of axial immobilization of the reverse gear 38 have not been shown.

In the example of Figure 1, all the helical teeth of the satellite 24 could be oriented in the same direction. It suffices for example to mount the transfer clutch 66 in the opposite direction to that shown, that is to say with the movable plate 78 on the right side by relative to the discs and relative to the axial stop 92, the weights then being placed to the right of the movable plate.

Claims

1 - Transmission device comprising:

- an input shaft (4);

- an output shaft (6);

5 - a differential gear (21) in which a satellite stage (24) mounted on a planet carrier (22; 222) comprises at least two stages of teeth (26, 27, 28, 29; 228; 1 39) each meshing with a respective one of several forward axial teeth (31, 32, 33, 34; 232; 1 41) located on the same side of the satellite (24) while a certain 10. (24) of the stages of teeth also mesh with axial reverse gear teeth (38), located on the other side of the satellite (24);

- connection means (1 2) between on the one hand at least one primary toothing (31; 141) forming part of the forward axial teething and on the other hand a first (4) of the input and output shafts ;

15 - secondary selection means (57, 58, 59, 61, 79; 258) for selectively connecting the other (6) of the input and output shafts to the axial reverse gear teeth (38) and to secondary teeth (32, 33, 34; 233) forming part of the forward axial teeth;

- control means (74, 84, 86, 87, 91, 92, 93, 94, 96, 0 99, 1 04, 1 06; 274; 286; 293; 292, 296) for controlling the selection means.

2- Device according to claim 1, characterized in that the forward axial teeth (31 to 34; 233; 1 41) are carried by planetary wheels (1 1; 1 42) and the reverse axial teeth 5 ( 38) is a crown.

3- Device according to claim 1 or 2, characterized in that the planet carrier (222) is fixed around the axis (7) and the secondary selection means comprise multi-disc clutches (62, 63, 64, 66, 81; 263) centered on the axis and located radially outside 0 relative to the satellite (24) and the axial teeth (31 to 34; 233; 1 41). 4- Device according to claim 1 or 2, characterized in that it comprises release means (101, 1 02) to selectively allow axial rotation of the planet carrier (22).

5- Device according to claim 4, characterized in that the release means are permissive in a state where the connecting means (1 2) and the output shaft (6) are connected to one another without passing by a meshing relationship in the differential gear (21).

6- Device according to claim 4 or 5, characterized in that the release means comprise a direct drive free wheel (1 01) mounted to prevent the reverse rotation of the planet carrier (22).

7- Device according to claim 6, characterized in that the release means comprise a brake (1 02) mechanically mounted in parallel with the direct drive freewheel (1 01).

8- Device according to one of claims 3 to 7, characterized in that it comprises means (1 66, 1 67) for selective blocking of the axial reverse gear teeth (38).

9- Device according to one of claims 1 to 8, characterized in that the tooth stage which has the largest diameter on the satellite (24) is a primary stage (26; 1 39). 10- Device according to one of claims 1 to 9, characterized in that the selection means comprise selective transfer coupling means (61) selectively connecting the primary teeth (31) with said other shaft (6).

1 1 - Device according to claim 1 0, characterized in that the control means comprise means (92) for transmitting to the selective transfer coupling means (61), in the direction of uncoupling, a PAP toothing reaction taking birth in the primary teeth (31) when it transmits a motor torque to the satellite (24). 1 2- Device according to one of claims 1 to 1 1, characterized in that the connecting means (1 2) comprise a mechanism primary (1 08) capable of a first and a second state each defining a respective transmission ratio between the first shaft (4) and the primary teeth (31).

13- Device according to claim 1 2, characterized in that the primary mechanism (1 08) comprises:

- a primary gear functionally mounted between said first shaft and a transfer shaft (1 3) connected to the primary axial teeth (31);

- a direct drive clutch (1 22) between the first shaft (4) and the transfer shaft independently of the primary gear;

- centrifugal elements (1 29) urging the clutch (1 22) to tighten by giving the clutch a torque transmission capacity which is a function of a rotation speed of the primary mechanism (1 08); - means (1 33) for transmitting to the clutch (1 22), in the direction of release, a reaction (PAC) originating in the primary gear when it operates under load.

14- Device according to one of claims 1 to 1 1, characterized in that the at least one primary axial forward toothing comprises a primary transfer toothing (31) and a substitute primary toothing (1 41) and in this that the device comprises primary selective coupling means (148, 149; 348, 349) capable of a first coupling state between the first shaft (4) and the primary transfer teeth (31) and a second state of coupling between the first shaft (4) and the substitutive primary teeth (141).

15- Device according to claim 1 4, characterized in that in the second state of the primary coupling means the secondary selection means can connect the primary transfer teeth with said other shaft (6) independently of the differential gear (21 ) . 16- Device according to claim 1 4 or 1 5, characterized in that the primary transfer teeth (31) is placed axially between the substitute primary teeth (1 41) and the secondary teeth (27, 228).

17- Device according to one of claims 1 4 to 1 6 characterized in that the primary selective coupling means comprise:

- a primary clutch (1 49; 349) between the first shaft (4) and a first of the primary transfer teeth (31) and the substitute primary teeth (1 41);

- a primary freewheel (148; 348) between the first shaft (4) and a second of the primary transfer teeth (31) and the substitute primary teeth (141).

18- Device according to claim 1 7, characterized by a retained operating clutch (1 57; 357), mounted in parallel with the primary free wheel (1 48; 348). 19- Device according to one of claims 1 2 to 1 8, characterized in that the multiplicative difference between two successive reports defined by the state of the connecting means is substantially equal to the square root of a multiplicative difference between two successive reports defined by the state of the secondary selection means (62; 258; 61). 20- Device according to one of claims 1 to 1 9, characterized in that between said other shaft (6) and a secondary axial toothing (32, 33; 233) corresponding to a transmission ratio smaller than another ratio transmission defined by another forward axial toothing (31, 34), the secondary selection means comprise a selective coupling device (62, 63; 262, 274; 263) mechanically mounted in series with a secondary freewheel ( 67, 68; 268).

21 - Device according to claim 20, characterized by a retained coupling device (1 37) mounted in parallel with the secondary free wheel (268). 22- Device according to one of claims 1 to 1 9, characterized in that the secondary selection means comprise:

- at least one assembly comprising a selective coupling device (62, 63; 262; 274; 263) mechanically mounted in series with a secondary freewheel (67, 69; 268), between at least one respective secondary axial toothing (32 , 231; 233) and the output shaft (6), to define at least one respective low transmission ratio;

- a transfer device (61) capable of connecting the output shaft (6) with the primary teeth (31). 23- Device according to one of claims 1 to 1 3, characterized in that the secondary selection means comprise:

- at least one assembly comprising a selective coupling device (62, 63; 262; 274) mechanically mounted in series with a secondary freewheel (67, 68), between at least one respective secondary axial toothing (32, 33) and the output shaft (6), to define at least one respective low transmission ratio;

- an intermediate selective coupling device (59; 258) mounted between the output shaft and secondary axial teeth of intermediate diameter (34; 233); - a transfer device (61) capable of connecting the output shaft

(6) with the primary teeth (31).

24- Device according to claim 22 or 23, characterized in that the selective coupling device of said assembly comprises a clutch (274) movable between a coupling position in said assembly and a decoupling position in said assembly and coupling between the reverse axial teeth (38) and the output shaft (6).

25- Device according to one of claims 22 to 24, characterized in that the control means comprise for at least one selective coupling devices belonging to the secondary selection means: - a centrifugal actuator (84, 86, 87; 286) for tightening the selective coupling device;

- means (93, 94; 292; 293) for transmitting to the selective coupling device, in the direction of loosening, a reaction force (PAS., PAS2, PASÎ) originating in the secondary axial teeth corresponding to a ratio immediately lower than that with which the selective coupling means is associated.

26- Device according to claim 25, characterized in that it comprises means (96, 94; 296; 292) for transmitting in cascade a tooth reaction force (PASI) originating in a certain secondary axial toothing (32) at least two selective coupling devices (63, 64; 263; 66) associated with forward axial teeth (33, 34; 233, 31) defining higher ratios than that defined by said certain secondary axial teeth. 27- Device according to one of claims 1 to 26, characterized in that it comprises an output rotor (46), connected to the output shaft (6) and having a bell shape surrounding the axial teeth (31 at 34, 233, 1 41, 38) and the satellite (24), secondary rotors (39, 41 to 43; 242) each connected to a respective one of the forward axial teeth, mounted in succession one in the others and inside the output rotor (46), and in that the secondary selection means are at least partly installed to selectively connect each secondary rotor with the output rotor, those of the secondary selection means which are associated to a secondary rotor which is located inside at least one other secondary rotor being arranged axially beyond the end of this at least one other secondary rotor.

28- Device according to claim 27, characterized in that the forward axial teeth comprise a distal secondary tooth (32) surrounding at least one securing member (52, 53, 1 3) between another of the forward axial teeth and the secondary rotor associated with this other forward axial toothing. 29- Device according to claim 28, characterized in that said at least one securing member comprises at least one tube (52, 53) surrounding, in turn, another securing member (53; 1 3). 30- Device according to claim 28 or 29, characterized in that a central securing member (1 3) connects the primary teeth (31) to a secondary rotor (39) which is associated with it.

31 - Device according to one of claims 26 to 30, characterized in that the secondary selection means comprise reverse gear selection means (79) installed between the axial reverse gear teeth (38) and the output rotor ( 46) beyond the axial end of the secondary rotors (39, 41, 42, 43; 242).

32- Device according to claim 31, characterized in that a secondary rotor (41) located furthest inside corresponds to a lower transmission ratio, and the reverse gear selection means (79) are adjacent to means (57) for selecting said lower gear, with between them a common reversing member (74; 274).