FR2806143A1 - Motor vehicle automatic transmission has input shaft carrying drive gears engaging frrely rotating gears on driven shaft which can be selectively locked to shaft - Google Patents

Abstract

The motor vehicle automatic transmission has an input shaft (18) carrying drive gears (20) which each mesh with a driven gear (22) mounted for free rotation on a driven shaft (12). Uni-directional locks (24) are mounted between the driven shaft and gears. The locks can be actuated mechanically by a cam (26) movable inside the driven shaft. A control (32) for the cam actuators (26,28,30) and a clutch (e2) determines the speed of the input shaft as a function of the operative overall gear ratio.

Description

 The present invention relates to a torque transfer automated transmission device, in particular for a motor vehicle, allowing a gear ratio change without interruption of a torque between a motor shaft and a driven shaft.

Disclosed are torque transfer transmissions comprising an input shaft which is connected to a drive shaft by a clutch and which carries drive gears, a driven shaft which carries driven gears, each drive gear being constantly engaged with a driven gear and defining a transmission ratio, the driving gears being integral in rotation with the input shaft and the driven gears being free to rotate on the driven shaft and being associated with means of synchronization and interconnection which selectively connect a driven pinion and 1 driven shaft, for engaging a given transmission ratio.

One of the driving gears, for example that of the last gear ratio, is connected to the input shaft by a clutch, the corresponding driven gear being rotatably connected to the driven shaft. By controlling the clutch of the driving gear of the last transmission ratio, it is possible to control the speed of rotation of the input shaft of the transmission during a transmission ratio change and to make it take a determined value enabling the engagement to take place. a new transmission report.

Clutching the drive gear clutch of the last transmission ratio during a shift also helps maintain a driving torque on the driven shaft during gearshift.

In the known torque transfer transmission devices, the control of the synchronization and interconnection means is relatively delicate, the declutching must take place when the driving torque of the driven gear is substantially zero, the interconnection to be performed when the rotational speed of the driven gear is equal to that of the driven shaft, so that the control means of these synchronization and interconnection means must be relatively very accurate and are relatively complex. Also known is an automated transmission with torque transfer, in which the usual means of synchronization and interconnection are replaced by one-way locking mechanisms of the gearwheel and ratchet type, which are controlled by magnetic means comprising permanent magnets carried. by a movable rod cooperating by magnetic attraction or repulsion with permanent magnets carried by the toothed wheels and by the pawls of the unidirectional locking mechanisms. This magnetic control "without contact" has the disadvantage of not guaranteeing the movement of the pawls between their rest and operating positions, the control rod carrying the permanent magnets being freely movable relative to the pawls, even if they do not move not as expected.

The object of the invention is in particular to avoid these drawbacks of the prior art, while simplifying the control and actuation means used in an automated transmission with torque transfer for a gear ratio change.

It proposes, for this purpose, a device of the aforementioned type, intended to connect a drive shaft and a driven shaft and comprising an input shaft, drive gears mounted on the input shaft, driven gears mounted on 1 ' driven shaft, each driving pinion being constantly engaged with a driven pinion and defining a transmission ratio, one of the pinions of each ratio being integral in rotation with its shaft and the other being free to rotate on its shaft, at least one clutch connecting the drive gear of the last transmission ratio to the input shaft, and means for selectively securing each free gear and its shaft for the engagement of the corresponding transmission ratio, these means comprising, for at least one pinion free, two controlled unidirectional locking mechanisms, mounted in opposite directions between the free pinion and its shaft to prohibit a speed of rotation of the lower free pinion, or higher respectively, to the speed of rotation of its shaft and each of which can occupy two positions, one of rest and the other of service, characterized in that these locking mechanisms are associated with mechanical actuation means comprising at least one displaceable cam in translation and / or rotation which acts positively on said mechanisms to bring them into the service position, control means of actuating means and said clutch being provided for controlling the rotational speed of the input shaft as a function of the transmission ratio change to be made.

The cam actuation of the aforementioned unidirectional locking mechanisms ensures the movement of these mechanisms in their operating position by the displacement of the cam which is itself positively controlled by mechanical means. This results in great operational safety, allowing the automatic control of the transmission.

According to another characteristic of the invention, the transmission ratio changes which do not relate to the last gear, comprise the same sequence of operations for actuating the unidirectional locking mechanisms for the rise and fall of the ratios, this sequence being executed in a specific order for the rise of the reports and in the reverse order for the descent of the reports. Therefore, the actuating means of the aforementioned unidirectional locking mechanisms may comprise a single actuator, which acts in one direction for the rise of the reports and in the other direction for the descent of the reports. This results in a great simplification of the control of the transmission. In a first embodiment of the invention, the idle gears are arranged in the order of transmission ratios and the device comprises a single cam movable in translation within the shaft carrying the idle gears. In another embodiment, the free sprockets are arranged on their shaft in the order 1, 3, 5, ..., 2, 4, 6 ... and the device comprises two cams movable simultaneously in translation to the said shaft 1, 3, 5, ..., the other for the actuation of the locking mechanisms of the free gears of the ratios 2, 4, 6, ...

Advantageously, the two cams are carried by the same support and the stroke of each cam is reduced by half compared to the embodiment comprising only one actuating cam of the aforementioned mechanisms.

In another embodiment of the invention, the idle gears are arranged on their shaft in the order 1, 4, 2, 5, 3, 6, the device then comprising three cams movable simultaneously in translation within the shaft bearing the idler gears, one for the actuation of the locking mechanisms of the free gears of the ratios 1 and 4, the second for the actuation of the locking mechanisms of the free gears of the ratios 2 and 5, and the third for the actuation of the locking mechanisms of the free gear ratio 3.

The invention thus makes it possible to vary the relative arrangement of the transmission ratios in a torque transfer transmission device and thus to choose a configuration according to the constraints imposed by other factors.

In a preferred embodiment of the invention, the cams are displaceable in translation by a screw-nut system, whose nut carries the cams and whose screw is a threaded rod driven in rotation by an actuator such as a motor. electric. Advantageously, the nut is guided in translation and immobilized in rotation on a fixed axial rod on which it is engaged at one end, and screwed at its other end to said threaded rod. The cams may be rotatably fixed, or rotate in synchronism with the shaft in which they are mounted.

In a particular embodiment of the invention, the cam or cams are mounted by screwing on a fixed spindle in translation and connected to a motor member by an epicyclic gear, preferably a double epicyclic gear.

In this case, the cam rotates with the driven shaft and remains stationary in translation relative to the driven shaft until the drive member rotates the threaded rod in one direction or the other.

According to another characteristic of the invention, the transmission device comprises a second clutch connecting the drive shaft to the input shaft, the drive gear of the first transmission ratio being rotatably connected to the input shaft and the associated driven pinion being securable in rotation with the shaft driven by two unidirectional locking mechanisms of the aforementioned type.

In a variant, the second clutch connects the input shaft to the drive gear of the first transmission ratio, the driven pinion is integral in rotation with the driven shaft.

The second clutch mentioned above is used primarily for starting the vehicle.

Advantageously, vibration filtering means are provided on the motor shaft and / or on the input shaft of the device according to the invention.

In general, the invention combines the advantages of automated transmissions with hydrokinetic couplers and planetary gear trains and those of manual gearboxes, while avoiding their respective drawbacks.

The invention will be better understood and other characteristics, details and advantages thereof will appear more clearly on reading the description which follows, given by way of example with reference to the appended drawings in which: FIG. 1 is a schematic representation of a first embodiment of a transmission device according to the invention;

FIG. 2 is a partial schematic view of an alternative embodiment of the invention;

FIG. 3 is a schematic axial view of a unidirectional locking mechanism according to the invention;

FIG. 4 is a graph schematizing the operation of the unidirectional locking mechanisms of several transmission ratios; FIG. 5 is a graph illustrating the four possible cases of transmission ratio change as a function of the torque applied to the driven shaft and the rise and fall of the ratios; FIGS. 6 and 7 are tables representing the states of the unidirectional locking mechanisms in two possible cases of transmission ratio change;

FIGS. 8 and 9 are graphs illustrating the clutch controls during transmission ratio changes corresponding to the tables of FIGS. 6 and 7, respectively; Figure 10 is a schematic representation of an alternative embodiment of the device according to the invention;

- Figure 11 is a partial schematic representation in axial section of the portion of the device comprising the driven shaft; - Figure 12 is a partial schematic view illustrating a different arrangement of transmission ratios in a device according to the invention.

Referring first to FIG. 1 which schematically represents a first embodiment of an automated transmission device with torque transfer according to the invention, intended to connect the output shaft 10 of a heat engine M, such as an internal combustion engine for a motor vehicle, to a driven shaft 12 which is the output shaft of the device according to the invention and which, in the case of a motor vehicle, is intended to drive the driving wheels 14 in rotation through a differential 16.

The device according to the invention comprises an input shaft 18 which is connected to the output shaft 10 of the motor M by a clutch E. The input shaft 18 is parallel to the output shaft 12 and carries drive gears 20 each of which is in constant engagement with a driven gear 22 mounted on the output shaft or driven shaft 12, the pairs of engaged gears 20, 22 defining transmission ratios which are numbered from 1 to 6 and which are progressively increasing, the gears of different transmission ratios being mounted in the order of these reports on the shafts 18 and 12.

In this exemplary embodiment, the driving gears 20 of the ratios 1 to 5 are integral in rotation with the input shaft 18 and the driven gears of these ratios are free to rotate on the driven shaft 12 and can be fixed in rotation with the latter by means of controlled unidirectional locking means 24, each free pinion 22 being associated with two controlled unidirectional locking mechanisms 24 which are mounted in opposite directions between the pinion 22 and the shaft 12, one of these mechanisms being intended to prohibit the idle gear 22 to rotate faster than the driven shaft 12, the other mechanism being intended to prohibit the idle gear 22 to rotate slower than the shaft 12.

The driving pinion 20 of the sixth transmission ratio is free to rotate on the input shaft 18 and is secured in rotation therewith by means of a clutch E2 which is for example mounted at the end of the shaft input 18 on the opposite side to

1 'input clutch El.

The driven gear 22 of the sixth transmission ratio is rotatably connected to the driven shaft 12 and does not comprise a controlled unidirectional locking mechanism 24.

The means for actuating the mechanisms 24 are advantageously housed inside the driven shaft 12 and comprise at least one cam 26 mounted on an axial rod 28 of which one end is connected to an actuator 30, outside the driven shaft 12. A system 32 for managing and controlling the device according to the invention is connected to the clutches E1 and E2 and to the actuator 30 for the control transmission ratio changes and is also connected to motor control means M for information exchanges or actions.

The cam 26 can be fixedly mounted in rotation inside the driven shaft 12 and is then moved in translation inside the shaft 12, between the unidirectional locking mechanisms 24 of the free gears 22 of the first five reports. transmission by the axial rod 28 which is itself driven by the actuator 30 in translation inside the shaft 12 or in rotation, the axial rod 28 then being a fixed threaded rod in translation on which the cam 26 is mounted by screwing. A particular embodiment of the unidirectional locking mechanisms and their actuating means is shown in detail in FIGS. 2 and 3.

In this embodiment, an internal toothing 36 is formed in a large face of each free pinion 22 to cooperate with at least two pawls 38 integral in rotation with the shaft 12 and each of which is movable by a pusher 40 between a position of rest where it is spaced from the toothing 36 of the pinion 22 and a service position where it is engaged with this toothing by prohibiting the rotation of the pinion 22 around the shaft 12 in a given direction, which is indicated by an arrow at vicinity of each pawl 38.

The pushers 40 are guided in radial holes in the cylindrical wall of the shaft 12 and are displaceable radially outwardly by the cam 26. The pushers 40 act on the pawls 38 by means of elastically deformable means

42 such as compression springs which are mounted between the pushers 40 and pawls 38. Advantageously, the pushers 40 are tubular and the springs 42 are housed partially inside the pushers 40 and bear against the bottom of these pushers.

Other resilient members 44 such as leaf springs urge the pawls 38 in the direction tending to move them away from the internal toothing 36 of the pinion 22.

Pawls 38 and leaf springs 44 are mounted on spacer washers 46 which are integral in rotation with shaft 12 and which are arranged between free sprockets 22, coπme shown in Figure 2.

The cam 26 is mounted on the rod 28 and is integral in rotation with the shaft 12, by means of a longitudinal rib 48 engaged in a corresponding groove of the inner surface of the shaft 12. The rod 28 is fixed in translation inside the shaft 12 and is connected to the actuator 30 by an epicyclic gear and preferably a double gear such as that shown in FIG. 2.

In this embodiment, the output shaft of the actuator 30, which is for example a small electric motor, is connected to the sun gear 50 of a first epicyclic gear whose gateatellites 52 is integral with one end of the axial rod. threaded 28 and whose ring 54 is integral with that of a second epicyclic gear. The sun gear 56 of this second gear is fixed in rotation and its planet carrier is integral in rotation with the shaft 12. The gear ratios are the same in the two epicyclic gears, the first form a differential and the second a reducer. Under these conditions, the cam 26 which is rotated by the shaft 12 is fixed in translation on the axial rod 28 as the output shaft of the actuator 30 does not rotate. The rotation in one direction or the other of this output shaft makes it possible to move the cam 26 in translation in one direction or the other within the shaft 12. As the double epicyclic gear that connects the actuator 30 to the shaft 12 and the threaded rod 28 transmits virtually no effort, it can be conveniently made of plastic, for a relatively low cost. In the embodiment of Figures 2 and 3, the two controlled unidirectional locking mechanisms 24 which are associated with a free pinion 20 are on the same side of the pinion and are diametrically opposite to the axis of rotation.

In an alternative embodiment, these two mechanisms could be one on a side of the pinion and the other on the other side of the pinion, each mechanism may comprise a single ratchet or more.

The cam 26 is a substantially cylindrical tubular piece whose outer surface is shaped to include bearing surfaces for radially moving the pushers 40 outwardly when the corresponding locking mechanisms must be in the service position. As will be seen in the following, the same cam can successively control all the locking mechanisms of the free gears of the different transmission ratios, when it is moved in one direction, for the rise of the transmission ratios and when it is moved in The other direction for the descent of the reports.

Reference will now be made to FIGS. 4 to 9 to describe the operation of the device according to the invention. In what follows, it is assumed that the speed of rotation of the shaft 12 is constant and it is in this case that the manner in which the transmission ratio changes are controlled and made is described.

The following conventions will be used in this description, which are illustrated by FIGS. 4 and 5.

FIG. 4 is a graph showing the staggering of the rotational speeds of the motor shaft corresponding to the first four transmission ratios for a given constant speed of the output shaft 12. The references A1, B1, A2, B2, A3 , B3 and A4, B4 respectively denote the unidirectional locking mechanisms 24 associated with the driven gears 22 of the first four transmission ratios and their actions on the gears, as a function of the torque transmitted to the output shaft 12, which may be a driving torque positive designated by Cm> 0 exerting a traction on the vehicle or a negative engine torque designated by Cm <0, exerting a braking on the vehicle, and the direction of variation of the speed of rotation of the drive shaft 10, this speed being indicated by increasing values on the vertical axis of Figure 4.

In this figure, the references A are assigned to the unidirectional locking mechanisms which prevent the idle gears 22 from rotating faster than the output shaft 12 and the references B are assigned to the mechanisms 24 which prevent them from rotating less rapidly than the tree 12.

Figure 5 shows schematically the four possible cases of transmission ratio change as a function of the engine torque and the rise or fall of transmission ratios. Cases I and II are those for which the torque applied to the shaft 12 is positive, the case I corresponding to the rise (passage of the ratio N to the ratio N + 1) and the case II to that of the descent ( transition from the ratio N to the ratio Nl).

Cases III and IV are those where the engine torque applied to the shaft 12 is a negative torque (Cm <0), the case III being that of the descent of the ratio N to the ratio Nl and the case IV that of the rise of the ratio N to the ratio N + 1.

The table of FIG. 6 represents the states of the unidirectional locking mechanisms of the free gears of the ratios N and N + 1 in the case of the transition from the ratio N to the ratio N + 1 with a positive motor torque. The controls of the clutches E1 and E2 are shown schematically in FIG. 8 as a function of time.

Initially, the N ratio being engaged, the locking mechanisms associated with the driven gear 22 of this report are in operating position, which corresponds to A _N = E- = 1, the clutch El connecting the drive shaft 10 to the input shaft 18 being tightened or engaged, the clutch E2 associated with the driving gear of the sixth gear transmission being loosened or disengaged (as a rule, the idle state of a clutch is its engaged or tightened state, and its activated state is the disengaged state).

Under these conditions, the pawl (s) of the mechanism A _N which prevents the driven gear 22 of the ratio N from turning faster than the shaft 12, abuts on the internal toothing 36 of the driven gear, due to the fact that the torque motor transmitted to the shaft 12 is positive. When a transmission ratio shift control is given to shift to the higher ratio N + 1, the pawl (s) of the mechanism B _N which prevents the pinion 22 from turning slower than the shaft 12, do not abut on the internal toothing 36 of the driven gear, and can be released from this toothing. As the driven gear ratio N + 1 is driven by its pinion leading to a rotational speed which is greater than the shaft 12, the mechanism B ^ i of this pinion can be brought into the service position. A displacement of the cam 26 inside the shaft 12 simultaneously controls the resting of the mechanism B ^ and the bringing into operation of the mechanism B ^ i. We are then in the state represented in the second column of the table of FIG.

Then, the clutch E2 is controlled to move it to the partially engaged state, which will make it possible to transmit a torque through the driving pinion 20 of the sixth transmission ratio to the input shaft 18 and thus slow down the speed of rotation of this input shaft, since the output shaft 12 which rotates at a constant speed is then connected to the input shaft 18 by the sixth gear ratio.

The partial or progressive tightening of the clutch E2 thus causes a decrease in the speed of rotation of the input shaft 18 to a value equal to the speed of synchronization with the output shaft 12 via the N + 1 ratio. In these conditions, we can bring the mechanism A _N at rest, since its or pawls are no longer abut on the internal toothing of the associated pinion and simultaneously bring the mechanism A _{N + 1} in the service position. It is then in a state corresponding to the third column of the table of FIG. 6, illustrating the engagement of the report

N + l.

The states A _N = 0 and A _{N + 1} = 1 are obtained simultaneously, by displacement of the cam 26 in the same direction as above. The clutch E2 is then loosened or disengaged for the complete engagement of the ratio N + 1, with a resumption of support on _{N + 1} .

During the change of ratio N to N + 1, a positive motor torque is transmitted continuously to the shaft 12, firstly by the mechanism A 1 of the ratio N up to the at least partial tightening of

1 clutch E2, then by the sixth transmission ratio for a brief moment, and finally by the _{N + 1} mechanism of the ratio N + 1, the total duration of the transmission ratio change being

1 second or less. When the transmission ratio change takes place under conditions corresponding to case II (positive motor torque applied to the output shaft 12 and transition from the ratio N to the ratio N1), the procedure is as follows, summarized in the table of FIG. FIG. 7 and diagrammatically represented in FIG. 9, with a succession of locking mechanism control operations which is identical to that described for case I but which is performed in the opposite direction.

Starting from the state corresponding to the first column of the table of FIG. 8, with A _N = B _N = 1, the ratio N being switched on, and A _-1 = B _N-1 = 0.

When a shift command N-1 is given, partially clutch E2 of the drive gear of the sixth transmission ratio to transmit a torque at least equal to the engine torque and to lower the speed of rotation of the input shaft 18, as already indicated above, and the cam 26 is moved to the pinion 22 of the ratio N1 to bring the locking mechanism A - at rest and the mechanism A _x i into operation, which corresponds to the second column of the table of FIG. 7. Subsequently, the clutch E2 is gradually released, which transmits less torque, which has the effect of making it possible to increase the speed of rotation of the input shaft 18 and to come to bear on A ^ i. Then, the clutch E2 is quickly loosened and the cam 26 is moved again, in the same direction, to bring the locking mechanism B _M to rest and the mechanism B _{N 1} in use, which corresponds to the third column of the table in Figure 7.

By comparing the tables of FIGS. 6 and 7, it can be seen that the sequences of control operations of the locking mechanisms which are executed to change the transmission ratio with a positive motor torque are reversed from each other for the climb. transmission reports and for their descent. This assumes, of course, that the locking mechanisms are arranged in the same way on all the driven gears 22 of the transmission ratios 1 to 5.

When the engine torque applied to the output shaft is negative (the vehicle is under engine braking), the following cases I and II are brought back, by a temporary control of the engine, to change the transmission ratio. motor M to give a positive value to the motor torque applied to the output shaft, this positive value preferably being rather low.

The same procedure is applied when the engine torque applied to the shaft 12 has a value close to zero. This modification of very short duration (less than a second for example) is not perceptible by the driver of the vehicle and allows to use a single control law for all cases of change of transmission ratio. Consequently, the same actuator controlled by the management system 32 makes it possible to perform all possible cases of transmission ratio change. When it is necessary to go from the fifth to the sixth transmission ratio with a positive engine torque, the procedure is as described with reference to FIGS. 6 and 8, but the clutch E2 is left engaged so as to keep the sixth gear ratio engaged. In the opposite direction, when it is necessary to go from the sixth to the fifth gear, the procedure is as shown in FIG. 9, without having to first control the tightening of the clutch E2.

In all cases, the clutch El remains in the tightened state, this clutch being used only for starting the vehicle (passing from the neutral position to the first transmission ratio).

This clutch is also used to shift from neutral to reverse.

In the variant embodiment shown schematically in FIG. 10, the arrangement of the different gears on the input and output shafts is identical to that described with reference to FIG. 1, and the drive gear 20 of the first transmission ratio is free. in rotation on the input shaft 18 and is securable in rotation with it by means of the clutch El. The driven gear 22 of the first transmission ratio is rotatably connected to the output shaft 12 and is not equipped with the aforementioned locking mechanisms 24.

For the rest, this transmission device is identical to that of FIG.

The operation for transmission ratio changes is identical to that just described, except for the first transmission ratio which is controlled directly by the clutch El. The passage from the first to the second transmission ratio is effected by loosening the clutch E1 and tightening the clutch E2, then proceeding as shown in FIG. 8.

The passage from the second to the first gear ratio is effected by first tightening the clutch E2 and then after resting A2 and B2, by clamping the clutch El and simultaneously by loosening the clutch E2. In the variant embodiment shown in FIG. 11, the output shaft 12 is supported at its ends by bearings mounted in a casing 62 and comprises an output pinion 64 at one of its ends. Two cams 26 are rotatably mounted on a tubular support 66, one end of which forms a nut screwed onto the end of a threaded axial rod 28 whose other end comprises a pulley 68, a pinion or the like, connected by a synchronous transmission 70 to the actuator 30 which is remote. The other end of the tubular element 66 is guided in translation on a fixed axial rod 72 mounted on a wall of the casing 62 and comprising a longitudinal groove in which is engaged a lug carried by the tubular element 66, to immobilize this element in rotation. The axial rods 28 and 72 are aligned, almost end to end, within the output shaft 12.

In this device, the driven gears 22 of the different transmission ratios are alternately mounted on the output shaft 12, in the order 1, 3, 5, 2, 4, 6, the corresponding driving gears being mounted in the same order on the input shaft. One of the cams 26 controls the locking mechanisms of the driven gears of the ratios 1, 3 and 5, the other cam 26 controlling the locking mechanisms of the gear gears of the ratios 2 and 4.

FIG. 11 shows that the cams 26 which act on the diametrically opposed locking mechanisms of each free pinion 22, have symmetrical profiles with respect to a midpoint, located on the axis of rotation, for the actuation of the mechanisms according to to the sequences shown in Figures 6 and 7.

In FIG. 11, the positions of the cams corresponding to one actuation of the locking mechanisms of a driven gear are indicated by lines marked by numbers surrounded by a circle. The lines marked with non-circled numbers indicate the positions taken by a cam when it is the other cam that acts on locking mechanisms of a driven gear. By for example, the number 2 between the numbers 1 and 3 in the circles indicates the position of the left cam when the right cam is in the operating position of the locking mechanisms of the second gear driven gear, this position being indicated by the number 2 surrounded by a circle. The small intermediate lines between the positions marked by numbers correspond to intermediate positions occupied by the cams during a change of transmission ratio.

This embodiment has a reduced axial size, thanks to the ca ces drive by a screw-nut system of reduced length, however, allowing good axial guidance of the cams 1 and immobilization in rotation of their support.

In the embodiment variant shown schematically in FIG. 12, the driven gears (as well as the driving gears) of the different transmission ratios are arranged in the order 1, 4, 2, 5, 3, 6 and the means for actuating the drives. locking mechanisms associated with these pinions comprise three cams 26 simultaneously movable in translation within 1 'shaft 12 by the axial rod 28, each cam can occupy four positions which are represented by broken dashed lines. The cam 26 of the left can actuate the locking mechanisms of the gear gears of reports 1 and 4, the cam 26 of the middle can actuate the locking mechanisms of the gears led reports 2 and 5, and the cam 26 of the right can actuate the mechanisms locking the third gear.

Various modifications can be made to the devices that have just been described without departing from the scope of the invention. For example, the idle gears may be carried by the input shaft 18 and not by the input shaft 12. Alternatively, some idle gears may be mounted on the input shaft 18 while the others are on the output shaft 12. It is advantageous that all the idle gears are associated with controlled unidirectional locking mechanisms of the type described, and some of them could be equipped with the usual means of synchronization and interconnection, if necessary.

Of course, the transmission device according to the invention comprises a reverse ratio, of which a driving gear is mounted on the input shaft 18, an intermediate gear reversal of the direction of rotation is mounted on an intermediate shaft parallel to the shafts 12 and 18 and a driven pinion is mounted on the output shaft 12 and is equipped either with conventional means of synchronization and interconnection or controlled unidirectional locking mechanisms of the type indicated above.

Claims (2)

1 - Automated torque transfer transmission device, in particular for a motor vehicle, for connecting a drive shaft (10) and a driven shaft (12) and comprising an input shaft (18), driving gears (20) mounted on the input shaft, driven pinions (22) mounted on the driven shaft (12), each driving pinion being constantly engaged with a driven pinion (22) and defining a transmission ratio, one of the pinions of each ratio being integral in rotation with its shaft and the other being free in rotation on its shaft, at least one clutch (E2) connecting the drive gear of the last transmission ratio to the input shaft (18), and means for selectively fastening each free pinion and its shaft for one engagement of the corresponding transmission ratio, comprising, for at least one idle gear, two controlled unidirectional locking mechanisms (24), mounted in opposite directions between the free pinion (22) and its shaft (12) to prohibit a speed of rotation of the lower free gear, or higher respectively, to the rotational speed of its shaft (12), and can each occupy two positions, one of rest and the other of service , characterized in that the aforementioned locking mechanisms (24) are associated with mechanical actuating means comprising at least one cam (26) displaceable in translation and / or rotation which acts positively on said mechanisms to bring them into position. operating position, and means (32) for controlling the actuating means (26, 28, 30) and the clutch (E2) for controlling the rotational speed of the input shaft (18) in function of the change of transmission ratio to be performed. 2 - Device according to claim 1, characterized in that, for a gear ratio change which does not relate to the last gear, the control of the clutch (E2) comprises at least a partial tightening of this clutch, followed by loosening. 3 - Device according to claim 1 or 2, characterized in that the transmission ratio changes which do not relate to the last report, comprise the same sequence of operations of operation of the locking mechanisms (24) for the rise and fall. descent of the reports, this sequence being executed in a determined order for the rise of the reports and in the reverse order for the descent of the reports. 4 - Device according to claim 3, characterized in that said sequence of operations comprises, for the passage of a gear engaged to a gear to engage, the resting of a first locking mechanism of the gear engaged and putting in operation of a first locking mechanism of the gear to engage, with a partial progressive tightening of the clutch (E2), the putting into service of the second locking mechanism of the report to engage and simultaneously the resting of the second mechanism of locking the gear engaged, with a complete loosening of the clutch (E2). 5 - Device according to one of the preceding claims, characterized in that the free gears (22) transmission ratios are carried by the driven shaft (12). 6 - Device according to one of the preceding claims, characterized in that the free gears (22) are arranged in the order of transmission ratios and in that it comprises a single cam (26) movable in translation to the inside the shaft (12) carrying the free gears. 7 - Device according to one of claims 1 to 5, characterized in that the free sprockets are arranged in the order 1, 3, 5, ..., 2, 4, 6 ... transmission ratios and in it comprises two cams (26) movable simultaneously in translation within said shaft (12), one for one actuation of the locking mechanisms of the free gears of the ratios 1, 3, 5, ..., the other for one actuation of the locking mechanisms of the gears free ratios 2, 4, β, ... 8 - Device according to one of claims 1 to 5, characterized in that the free gears are arranged in the order 1, 4, 2, 5, 3, 6 of the transmission ratios and in that it comprises three cams (26) movable simultaneously in translation within said shaft (12), one for the actuation of the locking mechanisms of the free gears of the ratios 1 and 4, the second for the actuation of the locking mechanisms of the free gears ratios 2 and 5, and the third for the actuation of the locking mechanisms of the free gear ratio 3. 9 - Device according to claim 7 or 8, characterized in that the cams (26) are movable in translation by a screw-nut system, whose nut (66) carries the cams (26) and whose screw is a rod threaded (28) driven in rotation by an actuator such as an electric motor. 10 - Device according to claim 9, characterized in that the nut (66) is guided in translation and immobilized in rotation on a fixed axial rod (72) on which it is engaged at one end, and is screwed to its other end on the threaded rod (28). 11 - Device according to one of the preceding claims, characterized in that the two locking mechanisms (24) of each free pinion are mounted axially on the same side of the free pinion and are for example diametrically opposed. 12 - Device according to one of claims 1 to 10, characterized in that the two locking mechanisms (24) of each free pinion are mounted axially on either side of the free pinion. 13 - Device according to one of the preceding claims, characterized in that each locking mechanism (24) comprises a locking member such as a pawl (38) cooperating with a toothing (36) formed on a side of the free gear for allow the rotation of the pinion in one direction and prohibit it in the opposite direction, a pusher (40) actuated by a cam (26) above for the movement of the pawl in a service position where it cooperates with the toothing (36) above , and a return spring (44) urging the pawl to a rest position where it is spaced from the toothing (36) above. 14 - Device according to claim 13, characterized in that the pawls (38) are carried by washers (46) interposed between the free gears (22) and integral in rotation with the shaft (12) of the free gears. 15 - Device according to claim 13 or 14, characterized in that the pushers (40) for moving the pawls extend radially into holes in the tubular wall of the shaft (12) above and cooperate with the pawls by the intermediate of elastically deformable members (42). 16 - Device according to one of the preceding claims, characterized in that the or each cam (26) is fixed in rotation. 17 - Device according to one of claims 1 to 15, characterized in that the or each cam (26) is rotated by 1 'shaft (12) of the free gears. 18 - Device according to claim 17, characterized in that each cam (26) is mounted by screwing on a threaded rod (28) fixed in translation and connected to a motor member by an epicyclic gear. 19 - Device according to claim 18, characterized in that the epicyclic gear is a double epicyclic gear. 20 - Device according to one of the preceding claims, characterized in that it comprises a second clutch (El) connecting the drive shaft (10) to the input shaft (18), the driving gear (20) of the first transmission ratio being integral in rotation with the input shaft (18) and the associated driven gear (22) being integral in rotation with the driven shaft (12) by locking mechanisms (24) above. 21 - Device according to one of claims 1 to 19, characterized in that it comprises a second clutch (El) connecting the input shaft (18) to the driving gear (20) of the first transmission ratio, the driven pinion is integral in rotation with the driven shaft (12).