FR3111401A3 - Mechanical transmission - Google Patents

Abstract

The invention is a very simple and very rustic stepped mechanical transmission, the ratio of which can vary automatically according to the torque to which its output shaft is subjected or according to any other parameter, and which produces no acyclism. It comprises a selector which can simultaneously connect two elementary transmissions, but it is provided with a means called conflict management between elementary transmissions, which disconnects in this case one of these two elementary transmissions. Abstract Figure: Fig. 1

Description

Mechanical transmission

The invention is a mechanical transmission that is very simple and rustic in design, does not need to be disengaged in order to be able to change gears, does not require synchro either, and is very easy to make automatic by simple mechanical means. .

Technical problem

Many engineers have designed manual or automatic gearboxes making it possible to dispense with the clutch and synchro, such as claw gearboxes, for example, but they have ended up with designs that are complex, fragile and costly to produce.

A very large number of documents are known describing manual and automatic gearboxes and in particular the following three documents.
- GB758516 (A) dated October 3, 1956 by Thomas Hindmarch, which describes a transmission whose input shaft drives pinions engaging with a pinion on the output shaft, at least one pinion on the input shaft input being provided with a speed-selective friction clutch and at least one pinion on the output shaft being provided with a freewheel.
- GB2193766 (A) of February 17, 1988 by Eric Albert Whateley, which describes a transmission comprising two friction clutches and two freewheels, and control means for disengaging one of the friction clutches.
- and WO2020020398 (A1) of January 30, 2020 by Ps Satyanarayana [IN] and Prajod Ayyyppath [IN] which describes a two-speed gearbox which comprises two gear stages, the first gear stage being fixedly connected to the input shaft and a first input gear connected to the output shaft via a freewheel, the input of the first gear stage and/or the input shaft being linked to the input of the second gear stage by a centrifugal clutch.

We also know the application PCT-FR-2019-000030 by Franck Guigan [FR] filed on March 6, 2019, which proposes to use a mechanical means allowing the crank pin of a crank to approach its axis of rotation under the effect of a force created by the torque to which the transmission is subjected, and/or to move away from it by its speed and/or by an elastic return, which has the effect of varying the amplitude of the back and forth movement comes from a connecting rod driven by this crankpin and controlling by a free wheel the rotation of an output shaft always in the same direction. We also know the documents cited by this application, those cited in his search report as well as the patent application FR1870485 by Franck Guigan [FR] filed on April 24, 2018 and the documents cited in his search report.

The invention will be well understood, and other aims, advantages and characteristics thereof will appear more clearly on reading the description which follows, which is illustrated by FIGS. 1 to 37 which all represent devices or part of devices according to the invention.

To simplify the presentation,
- it will be said below that an elementary transmission is "connected" or "engaged" when the input shaft of the transmission according to the invention is mechanically linked in rotation to its input and that its output is mechanically linked in rotation with the output shaft of the transmission according to the invention, and that it is "disconnected" or "disengaged" when at least one of these two mechanical connections is not made.
- we will call “adjacent” elementary transmission an elementary transmission whose main plane – that comprising its input or its output, such as a pinion, a crank, a connecting rod or a motor lever – is the closest to that of the elementary transmission considered,
- and an elementary transmission will be defined by its "rank" in the list of elementary transmissions whose transmission ratio increases, starting from the elementary transmission of rank 1 for that corresponding to the lowest transmission ratio also commonly called the " first gear”. Several adjacent elementary transmissions of increasing rank can thus be referred to as the “first speed”, the “second speed”, the “third speed”, etc.

as well as the following three are perspective views of a transmission according to the invention in a first embodiment, with parallel shafts, comprising three elementary transmissions 2001 2002 and 2003 each composed of two pinions, an input pinion driven by the input shaft 2 and an output pinion which can drive the output shaft 3. The elementary transmission 2001 is made up of input gears 201 and output 301, the elementary transmission 2002 is made up of input gears 202 and output 302, and the elementary transmission 2003 is made up of input 203 and output 303 gears. The transmission is seen in full in FIG. 1.

is a perspective view of this transmission stripped of its output pinions so that one can see the selector 40 which is a nut cooperating with the part of the output shaft 3 which is a screw 31. Two springs elastically maintain this selector in the same plane as the planes of rotation of the input pinion 202 and the output pinion 302.

is a perspective view of the output shaft 3 and its central part which is the screw 31 cooperating with the selector 40.

is a perspective view of the output shaft 3 provided with its selector 40, the abutment 42 of which can be driven in rotation by the abutment 502 of the output pinion 302. One can note the presence of a spiral spring 702 between the center of the output pinion and its periphery comprising the teeth, which dampens the shock during the connection of the elementary transmission considered.

is a perspective view of a version similar to that shown in the preceding figures, which is provided with a means for blocking the movement of the selector.

is a perspective view of a version similar to that shown in the previous figures, but whose selector 40 is moved manually along the axis of rotation of the output shaft 3, using a fork 3000 .

is a perspective view of three pinions 301 302 and 303 each comprising stops which can be rotated by the selector, one stop of which is provided with a wheel 4010.

is a perspective view of an improved selector, two stops of which are provided with wheels 4010 and 4010a, which can be shifted along the axis of rotation of the output shaft with respect to a central rest position. The selector 40 includes a movable part 4014 supporting the axes of rotation of the rollers, and this movable part can slide along this axis of rotation. Two springs 4015 and 4016 located on either side of the movable part 4014 maintain the latter in a central rest position.

is a perspective view of a stepped transmission according to the invention in a compact mode of implementation, the transmission ratio of which varies according to the torque to which the output shaft is subjected, and of which the two elementary transmissions are each constituted by one of the following two modes of transmission of an epicyclic gear train, the first of these modes being the transmission in direct drive from the input shaft 2 to the output shaft 3, the ring gear 300 rotating in the direction engine with the sun 202 and the satellites 252a 252b and following, this rotational movement being permitted by the freewheel with claws 602, the second being the transmission via the planetary gear train, the movement being transmitted successively from the sun 202 secured to the input shaft 2 to the satellites 252a 252b and following and to the planet carrier 263, the crown 300 remaining fixed.

is a perspective view of the output shaft 3 of the transmission of Figure 9, which includes a screw 31.

is a perspective view of the output shaft 3 of the transmission of Figure 9, provided with the selector 40 which cooperates with the screw 31 by moving along the axis of rotation of the output shaft 3 when it rotates with respect to this output shaft 3, and which comprises stops 41 42 and 43 which can rotate either by the torque supplied by the stops 501a and following integral with the input shaft 2, or by the torque supplied by the stops 502a, 502b and following secured to the planet carrier 263

is a perspective view of the transmission of FIG. 9, when this selector rotates by the torque supplied by the stops 501a and following fixed to the input shaft 2 to the stops 41 and following of the selector 40.

is a perspective view of the transmission of FIG. 9, when this selector rotates by the torque supplied by the stops 502a, 502b and following fixed to the planet carrier 263 to the stops 41 42 and following of the selector. We see the helical spring 803 which pushes the selector towards the plane in which the stops integral with the input shaft are located.

as well as the following two are perspective views which illustrate a variant of the transmission of FIGS. 9 to 13, which can operate both in forward gear and in reverse gear. The selector comprises in this case secondary stops 41A 42A and following. We distinguish the guide 6002 from the lug of the direction of rotation selector of the freewheel 602.

is a perspective view of the same transmission, cruising forward.

is a perspective view of the same transmission, this time in reverse and with output shaft drag that caused the selector to move along the axis of rotation of the engine, away from the engine so that it cooperates with the planetary carrier of the planetary gear train.

as well as the following three are perspective views of details of a two-way freewheel that allows the crown to rotate forwards. We distinguish the lug 6001 of the direction of rotation selector 6000, the crown 300 which includes a lug 3021 which is here locked in rotation by the pawl 6003.

is a perspective view of the same freewheel, but which here allows the crown to rotate only in reverse because the motor rotates in reverse, the pin 3021 being blocked in the opposite direction of rotation by the pawl 6004 .

is a perspective view of this freewheel with motor.

is a perspective view of this freewheel with the motor rotating in the opposite direction to that in which it rotates in Figure 19.

is a perspective view of a transmission of the same type as those represented in FIGS. 9 to 13, the crown 300 of which is replaced by a second sun 300, the satellites 252 and 252a each having two adjoining pinions of different diameters.

is a perspective view of a particular transmission similar to that shown in Figures 9 to 13, the crown of which is integral with a wheel 8.

is a perspective view of a transmission with parallel shafts, the elementary transmissions of which are engaged according to the torque transmitted to the input shaft. The elastic return 803 tends to move the ends of the shafts of the selector away from the axis of rotation of the input shaft 2, and the tension of this elastic return is adjustable by the cursor 804. One can distinguish a spiral spring 703 which allows the part of the toothed pinion comprising the teeth to shift angularly from its central part driving the freewheel under the force of a torque transferred by the pinion, in order to reduce the shock when this pinion begins to be driven.

is a view from another perspective of the transmission of figure 23 whose drive arms constituting the selector are here inside the input pinions, and we see the stops 501a and 501b of the first gear, which drive the input pinion 201.

is a perspective view of the same transmission seen from another angle, but here without its input pinions so that we can see the detail of the arms 401a 402a and 403a constituting the selector, which can pivot around a axis slightly distant from the axis of rotation of the input shaft 2

is an axial view of the first gear input gear 201 drive mechanism. On the left, the arms 401a and 401b of the selector rotate the stops 501a and 501b only, but on the right, the resistive torque having decreased, the positions of the arms could change, and their end then also drives the stops 502a and 502b of the input pinion 202 of the second speed which are only visible in the following figure.

is an axial view of the second gear input gear 202 drive mechanism. On the left, the arms 402a and 402b of the selector drive the stops 502a and 502b only, but on the right, the resistive torque having decreased, the positions of the arms could change, and their end then also drives the stops 503a and 503b of the pinion d entry 203 of the third speed which are only visible in the following figure.

is an axial view of the drive mechanism of the input pinion 203 of the third and last gear. Arms 403a and 403b drive stops 503a and 503b.

is a perspective view of a transmission with three elementary transmissions according to the invention, in another mode of implementation, the ratio of which changes according to the speed of rotation of the input shaft 2. It has three elementary transmissions corresponding to three different transmission ratios. The input shaft 2 rotates three input pinions of different diameters of which only the largest 203 is seen, via three selectors which are sets of drive arms 403a 403b and 403c, one end of which pivots around an axis close to the axis of rotation of the input shaft 2 and the other of which cooperates with a stop 503a or 503b secured to the input pinion 203. Each input pinion driven in rotation by the input shaft 2 can in turn drive in rotation by gear an output pinion driving the output shaft 3 by a free wheel. We see the freewheel 603 by which the output pinion 303 rotates the output shaft. The centrifugal force which applies to the shafts tends to move them away from the axis of rotation of the input shaft 2, but an elastic return 803 tends on the contrary to bring the ends of these shafts closer to the axis of rotation of the input shaft 2. The tension of this elastic return is adjustable by slider 804.

is a perspective view of a similar transmission, seen from the same side but from a different perspective. The input toothed pinions are not shown so that one can see the three selectors each consisting of a set of three drive arms. The drive arms are synchronized so that all of their ends are the same distance from the axis of input shaft 2.

is a perspective view from another angle of the same transmission, this time fitted with all its input gears.

is a perspective view of a drive arm synchronization mechanism 401a, 401b and 401c. Each of these three drive arms is secured to the homologous drive arms associated with the other two input pinions.

is a perspective view of an improved transmission, one of the elementary transmissions of which has a variable transmission ratio, comprising a crank 101 connected by a connecting rod 106 to a motor lever 105 which is flexible. This first transmission with three elementary transmissions is associated in parallel with another transmission also comprising three elementary transmissions of different ratios, called odd ratios to differentiate them from the so-called even ratios of the first transmission. It is therefore a six-speed gearbox, one of which has a variable transmission ratio, which can act as a clutch. Each transmits its movement to a clutch disc, 801 for odd gears and 802 for even gears. A movable clutch disc 800 cooperates alternately with one and with the other to benefit from the advantages of a robotized double-clutch transmission.

is a perspective view of a transmission part according to the invention in a particular embodiment. The input shaft 2 comprises a pinion rotating four satellites 252a 252b 252c and 252d.

is a perspective view of this complete transmission, provided with its four satellites each comprising a series of pinions integral with each other, each series of pinions being driven by a freewheel by one of the planets 252a 252b 252c and 252d. Each of these pinions drives in rotation a sun fixed to a ring comprising stops which can drive the stops of the selector. A distinction is made between sets of series of so-called even pinions 252a2 and 252a4 and series of odd satellites 252b1 and 252b3, which respectively drive the so-called even elementary transmissions and so-called odd elementary transmissions. Thus, when the selector 40 simultaneously connects two adjacent elementary transmissions, this does not cause a conflict.

is a perspective view of a transmission according to the invention in an embodiment with 8 forward speeds and two reverse speeds. The pinion 31 driven by the input shaft rotates three satellites 252a 252b which are stepped and correspond one to the so-called even speeds and the other to the odd speeds, and 252c which corresponds to the two reverse gait speeds. The sprockets 252b7 and 252a8 thus correspond respectively to the 7th and 8th gears.

is a perspective view of a detail of this transmission which shows that one of the two springs determining with the resistant torque the position of the selector are one a spring 4015 connected to the selector by a cable, and the other a spring of compression 4016 which is only compressed during reverse or forward engine braking.

All these figures illustrate arrangements chosen to enable the different methods envisaged to be clearly explained. Those skilled in the art can advantageously produce more compact versions, in particular for versions whose input and output shafts are aligned. It is in fact possible not to combine the length of the three sets which are the spring 803, the zone of movement of the selector 40, and the set of toothed pinions. These three series of elements can indeed be located in concentric cylindrical volumes that do not overlap.

The present invention is a mechanical transmission of movement from an input shaft 2 to an output shaft 3, called stepped transmission, comprising a plurality of means for transferring the movement of said input shaft to said output shaft, called elementary transmissions (2001, 2002 and 2003) each comprising an input which can be driven in rotation by said input shaft and an output which can be driven in rotation by said output shaft,
- at least two elementary transmissions capable of ensuring this motion transfer according to different transmission ratios,
- the input and the output of these two elementary transmissions being permanently mechanically connected, even when they do not transmit the torque from the input shaft to the output shaft,
- the stepped transmission being provided with at least one clutch means called selector 40 having the effect of putting an elementary transmission in a so-called connected configuration by mechanically linking its input to said input shaft or its output to said output shaft, or to the contrary to putting it in a so-called disconnected configuration by mechanically disconnecting its input from said input shaft or its output from said output shaft,
- said selector being able to have different positions and such a change of position having the effect of connecting or disconnecting one of said elementary transmissions,
characterized in that said selector can assume a position in which it would simultaneously connect two elementary transmissions, because said stepped transmission is provided with so-called conflict management means between elementary transmissions, which disconnects in this case one of these two elementary transmissions,
it being specified above and below that an output is said to be connected or engaged when the input shaft is mechanically linked in rotation to its input and that its output is mechanically linked in rotation to said output shaft, and disconnected or disengaged when at least one of these two mechanical connections is not made.

Detailed description of the invention

So-called stepped gearboxes generally comprise several elementary transmissions having different transmission ratios, a selection means making it possible to put one of these elementary transmissions into service by moving a so-called selector clutch means, such as for example a gearboxes and its walkmans.

The principle of the prior art is to ensure that two elementary transmissions cannot simultaneously transfer the rotational movement of the input shaft to the output shaft, because as they have by design different transmission ratios , it would cause a conflict.

The principle of the present invention is not to respect this principle, that is to say to accept that two elementary transmissions can be put into service simultaneously, while managing the conflict of competition between two elementary transmissions, in such a way only one of these two elementary transmissions actually transmits the rotational movement of the primary shaft to the secondary shaft.

The gearbox is therefore provided with a means of managing conflict between elementary transmissions which mechanically disconnects one of the two elementary transmissions put into service, which means that only one of these two elementary transmissions actually transfers the movement of the input shaft to the output shaft.

A first possible means of conflict management consists in the selector being provided with a so-called avoidance means modifying its position when its position would have the effect that two elementary transmissions are connected simultaneously, so that only one of these two elementary transmissions remain connected. Such avoidance means is illustrated in Figures 7 and 8. The stops 501 502 and following of the output pinions 301 or 302 or 303 have lateral ends which are pointed, and the stops of the selector 40 are each provided with a wheel , respectively 4010 and 4010a, which cooperate with these stops. When the axis of rotation of a caster is located in a plane comprising the pointed end of a stop of an output pinion of a first intermediate transmission, the caster considered actually connects this elementary transmission, but when this roller also meets the pointed end of the abutment of the output pinion of an adjacent elementary transmission, it ceases to be in balance and the selector 40 shifts laterally along the axis of rotation of the secondary shaft to only drive the first intermediate transmission in rotation. To implement this first means, it is recommended that the selector stop, or the selector itself, can shift slightly to end up opposite the stop of an output pinion. A rubber band can override this offset when it is no longer needed.

Figure 8 shows a particular mode of implementation of the avoidance means. The two stops 4010 and 4010a which are wheels here can be offset relative to the rest of the selector along the axis of rotation of the output shaft, and a mechanical means, such as for example two springs 4014 and 4015, has the effect of giving the stops a central rest position with respect to the selector 40. When the selector is not in the plane where it cooperates best with a pinion, these springs deform and allow the movable part 4014 of the selector to shift laterally so that a stop 4010 is located in the plane in which it cooperates best with the stop 501 of the nearest pinion.

A second possible means of conflict management, preferred, consists in that at least one of said connected elementary transmissions is provided with a one-way clutch called freewheel 601 allowing its output to rotate at the same speed as that of another transmission which is simultaneously connected and whose output rotates faster.

It is advantageous to combine the two means of conflict management which have just been described.

It is also possible to replace such a one-way clutch with an electromagnetic clutch.

In an improved version, not shown, the one-way clutch of an elementary transmission allows the output of the latter to rotate at the same speed as that of another transmission which would be connected simultaneously and whose output would rotate faster, while by rotating an energy storage means such as a flywheel or an electricity generator, to cushion the shock of operating the one-way clutch while recovering energy in some form or under another.

In a particularly advantageous version, represented in whole or in part in FIGS. 1 to 4 in particular, the change in position of the selector depends on the torque to which said stepped transmission is subjected.

It can also, as in the example shown in Figures 29 to 31, depend on the speed of rotation of the input shaft or the output shaft.

In these two cases, the change of position of the selector can advantageously be limited by a stop (not shown) which can be moved by hand or on command from a computer to select one or more elementary transmissions which can be put into service, by example to obtain an engine brake or a generation of energy during a slowdown.

In the following description, a freewheel is placed on an input pinion or on an output pinion, but the reverse arrangements to those described also work. Similarly, the selector 40 is presented as driving the output shaft or driven by the input shaft, and both solutions are possible. More generally, the input shaft and output shaft of the solutions described can be inverted, without departing from the scope of the invention, which provides different effects with different applications.

Figures 1 to 4 illustrate a preferred embodiment of a transmission according to the invention, with parallel shafts, comprising two forward gear ratios and two reverse gear ratios which change automatically depending on the direction in which the gear turns. input shaft 2 and the resistance to rotation of output shaft 3.

In this version, the selector can move along said output shaft or said input shaft, inside the mechanical elements which drive it or which it drives, as the case may be, along their axis of rotation. . It here moves along the output shaft which it drives, but could also move along the input shaft which would drive it in this case. Unlike the claws used in the prior art, this selector moves inside the pinions which drive it or which it drives, as the case may be, along their axis of rotation. This is what makes it possible to use a single selector for all the elementary transmissions of the stepped transmission.

The input shaft 2 is fixedly connected to the pinion 202, which is the gear pinion whose transmission ratio is the highest since it is the largest input pinion and it rotates the output pinion 302 which is the smallest. It always spins at the speed of the input gear.

The other two input sprockets are smaller and each connected to input shaft 2 by a freewheel, but these two freewheels are in opposite directions. If the motor rotates in one direction, the pinions 201 and 202 rotate in its direction of rotation, while if it rotates in the other direction, it is the pinions 202 and 203 that rotate in its direction of rotation. The presence of these freewheels has the consequence not only that the pinions 201 and 203 are driven in rotation only in the motor direction, but also that they can rotate faster than the pinion 202.

Each of the output gears 301 302 and 303 is driven by the input gear which is in the same plane, the output gear 301 by the input gear 201, the output gear 302 by the input gear 202 and the output pinion 303 by the input pinion 203. They drive the output shaft 3 by a selector 40 which is a nut cooperating with the output shaft which comprises a part forming a thread. The selector is held elastically in the plane of the pinions 202 and 302 one or two springs. The rest position of the selector is that in which it is driven by the output pinion 302.

When the engine starts to turn, the input shaft 2 therefore drives the pinion 202 which drives the pinion 302, which drives the output shaft 3 in second gear, but the resistance opposed by the output shaft moves the selector in one direction if the motor is running forward, and in the opposite direction if the motor is running in reverse. We are thus in both cases in first gear to begin with, until the acceleration having occurred, the resisting torque decreases and the transmission shifts to second gear, in the direction of rotation of the engine.

When the output shaft rotates faster than the speed of rotation communicated to it by the input shaft, which corresponds for example to a motorized vehicle in a descent or a deceleration, everything depends on the resistive torque opposed by the input shaft to that provided by the output shaft. If this torque is low, the input shaft is driven with a torque ratio inverse to that of the second gear, but once it exceeds the value at which the reverse gear changes to first gear, it is at the inverse of this torque ratio that the input shaft is driven by the output shaft. An engine brake is therefore obtained which is all the more multiplied as the resistance opposed by the engine is strong, which the user can obtain either by electronic means, or quite simply by lifting his foot from the accelerator.

Depending on the direction of the thread 31, it can be seen that it is therefore possible to obtain both a reduction and an increase in the torque ratio when the resisting torque increases or decreases. The applications are different, one of the two options is intended to transmit the movement of a motor to a wheel while the other mainly concerns the recovery of energy during slowing down and braking.

The designer of a transmission according to the invention can advantageously combine what has just been described with adjustable movable stops or electromagnets making it possible to modify the position of the selector to place it in the plane of the desired elementary transmission.

It should be noted that it is not possible for there to be a conflict between the selector and an output pinion, due to the presence of the freewheels, since if the selector is in an intermediate plane between those of two adjacent pinions, it is the pinion which turns the fastest, that is to say the pinion 302, which makes the output shaft turn, the pinion 301 or the pinion 303 then being able to turn as fast as it since , as seen above, pinions 201 and 203 can rotate faster than pinion 202.

It is obviously possible to have as many pairs of input and output gears as you want, to multiply the number of transmission ratios available.

One of the elementary transmissions may not be equipped with a freewheel, for example that corresponding to the last gear whose output pinion is always the one which rotates the fastest when the corresponding elementary transmission is connected.

The clutch means ensuring the selector function can advantageously be magnetic or electromagnetic to avoid any mechanical conflict such as for example a conflict of teeth.

The clutch means providing the selector function can also be a means (not shown) securing the pinion of an elementary transmission with that of another adjacent elementary transmission which is already engaged. Those skilled in the art know how to design radially grooved surfaces which provide this type of connection when one of these surfaces is pressed against another which is complementary to it. It is for example possible to install a spring between such a surface linked in rotation to a pinion and a similar surface linked in rotation to a pinion of the adjacent elementary transmission, these springs being chosen so that the pressure on the first pinion drives the pinions in a determined order from a so-called rest position in which they are free to a so-called working position in which a pinion is secured to that of the adjacent elementary transmission to rotate with it.

A recommended means, also not shown, may consist, for example, in a torque sensor consisting of a torsion bar mechanically causing one pinion to move closer or further from another in an adjacent elementary transmission, or a securing means between two pinions of the similar means which is adjacent to it. The volume in which this mechanism for securing two adjacent primary transmission pinions is installed can be a ring, and the inside and outside diameters of this ring can vary from one mechanism to the mechanism of the elementary transmission a to have the necessary space. to the operation of these mechanisms without enlarging the corresponding input pinions. This makes it possible to limit the total size of the stepped transmission.

An input pinion passing from a position disconnecting the elementary transmission to which it belongs to a position connecting it can pass through an intermediate stage (not shown) in which it is driven by friction, with the possibility of sliding providing the same effect. than a gearbox synchro. In the case where the clutch means is magnetic or electromagnetic, an input pinion may include magnets which attract each other when in the working position. The clutch function can thus be progressive and without dust or wear. In an improved mode, the magnet or the electromagnet can have two possible positions so as not to be attracted by another in the position of rest.

The selectors of a stepped transmission comprising means for securing in rotation a pinion of an elementary transmission with that of an adjacent elementary transmission can thus form a cumulative clutch means engaging from 0 to N pinions in a corresponding order to increasing or decreasing values of the torque ratio of the elementary transmission to which they belong.

When the transmitted torque or the rotational speed, as the case may be, is close to the disengaged condition of an elementary transmission, the staged transmission could switch on and off an elementary transmission at a rapid alternating rate, which is undesirable because it would cause jerks in the transmission and premature wear. To avoid this, it is desirable that the disengagement condition of an elementary transmission be different from a so-called clutch condition which is the one causing the engagement of the elementary transmission considered, this clutch condition possibly being that the torque to which the elementary transmission considered is subjected is greater than a predetermined value, or that the speed of rotation to which it is subjected is greater or less than a predetermined value, as the case may be.

An advantageous way of obtaining this result is for a selector to include a return means towards at least one position of equilibrium associated with an elementary transmission, this return means favoring the maintenance of the clutch of the elementary transmission considered even substantially beyond its engagement and disengagement conditions.

Those skilled in the art can also play on the shape of the stops of the output pinions and the stops of the selector to make the gear change more or less difficult. A selector can also be fitted with an elastic return giving it several preferred intermediate rest positions, or notches.

The change of position of the selector can also be controlled manually or by a computer to make a manual or robotic gearbox, as shown in Figure 5, which shows a transmission according to the invention devoid of its output sprockets, so that one can see the selector driving the output shaft 3 in rotation, this selector being able to slide using the fork 3000 along the output shaft in order to select the output pinion which must drive it in rotation. In this case, nothing prevents the selector from moving along the input shaft, and it can then connect different elementary transmissions with different characteristics, such as different forward or reverse transmission ratios, a dead point and one or more variable-ratio elementary transmissions that can serve as a clutch, for example.

The input shaft 2 and the output shaft 3 of the stepped transmission can be aligned as represented in FIGS. from the input shaft 2, or from the output of each of the elementary transmissions towards a pinion aligned with the input shaft and with the output shaft.

When two elementary transmissions are associated in series, it is more convenient for the axis of rotation of the output shaft of the second elementary transmission to coincide with that of the input shaft of the first elementary transmission.

These FIGS. 9 to 22 illustrate a particular implementation, in which an elementary transmission comprises an epicyclic train.

The input shaft rotates one of the three components of the planetary gear set. Above and below, the components of a planetary gear set are understood to mean the planet carrier equipped with its satellites, and the two sun gears (sun or crown). The planetary gear may comprise either a planet carrier, a sun and a ring gear, or a planet carrier provided with planet gears themselves comprising two toothed pinions of different diameters integral with each other, associated either with two rings of different diameters, or with two suns of different diameters (version not shown). These different types of planetary gear sets offer well-known different advantages, in particular as regards the direction of rotation of that of their components constituting the output shaft with respect to the direction of rotation of that constituting their input shaft, and the possibility of have very low or very high or very close to 1 gear ratios.

In the configuration shown, the elementary transmission of the lowest rank transmitting the movement consists of a clutch of the output shaft on the input shaft, directly or by an intermediate transmission means, the crown being able to rotate freely in the motor direction, but not in the opposite direction, because it is mechanically connected to the frame integral with the motor by a freewheel 602. The transmission is then in direct drive, the three components of the planetary gear train rotating together at the same speed of rotation. When this first elementary transmission is disconnected, the stepped transmission passes into a configuration in which the elementary transmission transmitting the movement is constituted by the operation of the planetary gear train itself, the three components of which rotate at different speeds, a freewheel preventing the crown to rotate in the opposite direction to the motor direction, so that the input shaft drives the output shaft at a lower rotational speed than that at which it would have been driven in the direct drive configuration described above.

In a particular version, instead of being mechanically connected to the frame integral with the motor by a freewheel 602, as illustrated by the figures, the ring gear can rotate in the opposite direction to that of the motor but by supplying a torque to a means of energy storage. The device then makes it possible to store the energy resulting from an overload in a transmission shaft. Such a device is advantageously associated in series with a transmission according to the invention to dampen the jolts resulting from the connection of an elementary transmission.

Many other combinations known to those skilled in the art can be envisaged with regard to the use of planetary gear sets such as what has just been described. The input shaft, integral with a first sun, can directly rotate the output shaft, as well as all the components of the planetary gear train at the same speed of rotation. In the event of a mechanical overload, the satellite(s) begin to rotate on their axis, the planet carrier being locked in rotation by a freewheel. A satellite has two cogwheels that are integral with each other, of different radii, so that the first cogwheel is driven by the first sun while the second one drives the second sun. The advantage of such an arrangement is that in this case there is no limitation as to the choice of the transmission ratios, since the choice of the diameters of the satellites and of the secondary sun is completely free. A satellite carrier can comprise several series of double satellites, to drive several suns corresponding to several different transmission ratios.

The transmission shown in Figures 9 to 22 has only two elementary transmissions, but there is nothing to prevent a transmission having a larger number of elementary transmissions from being designed according to the same principle. It is also possible to have a greater number of transmission ratios by combining such transmissions in series.

The stepped transmission represented by FIGS. 9 to 20 is provided with a general selector on its output shaft 3, and lets the ring gear rotate freely in the motor direction in one of the two possible positions of the selector 40. Thus, the transmission stepped can rotate in direct drive.

An improved version allows the motor to run in both forward and reverse. It is represented in FIGS. 14 to 20. The selector is moved both towards the motor and in the opposite direction, depending on the direction of rotation, and the freewheel allows the ring gear to rotate only in the motor direction.

The selector 40 comprises in this case two series of stops 42 and 42A. It can be seen in FIG. 14 that the stop 42A is driven by the stop 502 of the planet carrier, because the spring is compressed by an excessive resistant torque while the motor is running forward.

It can be seen that when the transmission rotates forward at cruising speed as illustrated by FIG. 15, that is to say when the torque to which it is subjected is below a determined threshold, it is the stop 41 of the selector which is driven by the input shaft stopper 501A. This is also the case when reversing, because the compression and tension of the spring would also be almost zero in this case.

In Figure 16, the transmission is in reverse but with excessive resistance from the output shaft. The spring then works in traction, and the selector is therefore closer to the motor. The stop 42A is driven in reverse by the stop 502 of the planet carrier.

Figures 17 to 19 illustrate an embodiment of a freewheel allowing the crown to rotate only in the motor direction. It always locks in the opposite direction to that of the motor. This freewheel comprises a ratchet ring 6000 guided by a pin 6001 sliding in a groove 6002, such that this ratchet ring moves along the axis of rotation of the motor either towards the motor when the motor is running. forward, or in the opposite direction when turning in the opposite direction. The pawl ring comprises two pawls 6003 and 6004 of opposite directions, and only one of them cooperates with a stop 3021 integral with the crown 302. It is the pawl 6003 which cooperates with the stop 3021 when the motor is running. forward and the pawl 6004 which cooperates with this stop 3021 when the motor is running in reverse.

When the reduction ratio must be high, a recommended solution to reduce the size and weight of the transmission - not shown - consists in having the input shaft drive a so-called second gear output shaft which is parallel to it. , by a pinion cooperating with a pinion secured to this second gear output shaft. The input shaft also drives an intermediate shaft which is parallel to it, via a pinion cooperating with a crown fixed to this intermediate shaft, and this intermediate shaft in turn drives via a pinion a so-called first speed output shaft which is coaxial with the second gear output shaft. Each of the two output shafts has tappets that can drive the stops of the general output shaft in rotation, as shown in Figures 14 and 15. To take an example, the pinion of the input shaft drives the output shaft. second gear output by a ratio of 1/4, and the countershaft by a ratio of 1/3, and the countershaft drives the first gear output shaft by a ratio of 8/3. The transmission ratio of first gear is thus 1/4 and that of second gear 1/8, each of these transmission ratios being thus available both in forward and reverse gear.

In the case where the engine torque is unstable during a cycle, as for example when it comes to the crankset of a bicycle or an internal combustion engine, it is advantageous for the change of position of the selector to be slowed down by a damping means (not shown).

In an improved version, at least one of the elementary transmissions has a variable transmission ratio depending on the torque to which it is subjected and/or its speed of rotation. This can for example make it possible to constitute a clutch without friction when the transmission ratio can become infinite as represented in figure 33.

It is possible to make simplified versions of transmissions according to the present invention. For example, the functions of one-way clutch called free wheel and of clutch means called selector can be obtained by two toothed pinions whose teeth are asymmetrical to obtain the one-way clutch effect, and by an elastic deformation of a any part of the elementary transmission considered to obtain the effect of the so-called selector clutch means. These two toothed pinions do not cooperate in one of the two possible directions of their respective rotations, and by playing on the flexibility of deformation of the toothed pinions, it is possible to favor the connection of an elementary transmission for a range of torque or rotational speed . This version is not shown.

It is of course possible to constitute an elementary transmission by assembling in series or in parallel several so-called primary transmissions, and these so-called primary transmissions can be of different natures, connecting and disconnecting according to different parameters such as torque or speed, or depending on a combination of two different types of parameters, or manually or on command from a computer.

An elementary transmission can also comprise several selectors of different characteristics. The possibilities are therefore very numerous. This makes it possible to engage an elementary transmission according to a combination of manual or computerized commands, and rotational speed and transmitted torque parameters.

A torque selector can be provided with a so-called sensitivity adjustment means making it possible to vary the value of the torque or of the speed causing the connection and disconnection of an elementary transmission. This means can modify the operating rules of a single selector or be common to several selectors.

Those skilled in the art have at their disposal very many means of varying the effect of the torque of the output shaft on a selector, as well as its elastic return to a so-called rest position. This is particularly easy when the clutch means is a means securing in rotation the pinion of an elementary transmission with that of one or more other elementary transmissions, because the elastic return can then be a simple spring located in the axis rotation of the primary shaft. The tension or compression of this spring can indeed easily be modified in real time during the rotation of the shaft and the pinions.

In the version shown in Figures 23 to 33, the transmission is provided with means for adjusting the stiffness of this elastic return, by a means consisting in varying the position of the slider 804 which slides in a rail fixed to the frame of the transmission.

Such adjustment means can also make it possible to disconnect one or more elementary transmissions, which thus provides a disengagement function to the transmission. It should be noted that this clutch occurs without friction, therefore without practically any loss of energy or wear or dust.

Such an adjustment means can also, indirectly, make it possible to select manually or by computer the connection or disconnection of an elementary transmission, and therefore to change the transmission ratio on command.

This improvement has an additional advantage which is that it allows the transmission to be fitted with a reverse gear, which can thus be disengaged when the transmission is operating in forward gear. Symmetrically, the elementary transmission or transmissions corresponding to the forward gear can be disengaged when the elementary transmission corresponding to the reverse gear is put into service.

In an improved version, at least one of said elementary transmissions (preferably the first gear) has a transmission ratio which varies according to the torque to which it is subjected or its speed of rotation. There are many ways of carrying out such transmissions, including those described in the aforementioned documents PCT-FR-2019-000030 and FR1870485.

It is also possible to produce double-clutch gearboxes according to the invention. Such a transmission is illustrated in FIG. 33. It comprises two sets of elementary transmissions corresponding to so-called even and odd transmission ratios as is widely known. Each of these elementary transmissions transmits its movement to a clutch disc, respectively 801 and 802. These clutch discs cooperate alternately with the output shaft 3 of the assembly via a third clutch disc 800. The advantage is to avoid shocks when putting a freewheel into service, since the latter is put into service before ensuring the transmission of the torque to the output shaft 3. This arrangement is therefore particularly suitable for transmissions power.

Another, simpler method, making it possible to avoid shocks during the commissioning of an elementary transmission can consist in providing any element of an elementary transmission with the possibility of elastic deformation such as the spiral spring 702 illustrated in FIG. 4 and that 703 illustrated in FIG. 23. The part of a toothed pinion comprising the teeth can for example shift angularly from the central part of this pinion under the force of a torque transferred by the pinion. Such a toothed pinion having the possibility of elastic deformation can equally well be an input pinion or an output pinion.

In general, to limit the shock suffered by the output shaft when connecting an elementary transmission, it is advantageous for any component of a transmission according to the invention to have the possibility of elastic deformation.

Another means of protection can consist in providing an elementary transmission with a centrifugal clutch, which has the effect that it drives the output shaft only after it has been engaged by the selector.

In another mode of implementation shown in Figures 23 to 33 the selector is constituted by a set of drive arms which directly or indirectly connect the input shaft to the output shaft of the elementary transmission to which it belongs when the torque to which the elementary transmission considered is subjected exceeds a determined value or is less than a determined value. This method is known because it is used for certain breaking torque limiters. The permanent connection of this drive arm can be located at either of its two ends, that closest to its axis of rotation or the other.

During a mechanical overload, a drive arm flexes and its mobile end ceases to cooperate with its means of mechanical connection with the input shaft 2 or with the output shaft 3, as the case may be. The input pinion is in this case no longer coupled to the input shaft 2, while the re-coupling is automatic. One can use rigid and articulated arms or flexible arms, or even arms which are both articulated and flexible. They can be provided with hooks as shown in Figures 29 and 30, or of various shapes as shown in Figures 24 to 28.

By adjusting the position of the center of gravity of this drive arm, it is also possible to activate and deactivate an elementary transmission according to the rotational speed of its input shaft or its output shaft. This is how the transmission of figures 29 to 31 works.

A drive arm can be provided with an elastic return giving it several preferred intermediate rest positions, or notches. More generally, such a selector may be provided with an elastic return allowing it to be put into service or out of service only within a limited range of transmitted torque or speed as the case may be. This prevents two neighboring elementary transmissions from being selected alternately by switching too frequently from one to the other when their torque or rotational speed limiter is close to the speed at which it comes into service.

The connection between a drive arm and the pinion which it drives can be mechanical or magnetic. In general, all known types of torque or speed limiters can be used.

Figure 32 shows a drive arm synchronization mechanism 401b and 401c. Those skilled in the art can use such a mechanism to move not three arms each supporting a support of an elastic link 804, but a larger number of such supports so that they together form a path that remains substantially circular for all positions of the drive arms (version not shown). The tension of the elastic link 804 can then easily be modified in real time by the user, either with a manual control by cable or by the use of electrical means which can be controlled by computer. In the case of a car, for example, the tension of this elastic link can be modified by pressure on the accelerator pedal.

In an improved version represented in FIG. 33, at least one of said elementary transmissions (here the first gear) has a transmission ratio which varies according to the torque to which it is subjected or its speed of rotation. There are many ways of carrying out such transmissions, including those described in the aforementioned documents PCT-FR-2019-000030 and FR1870485.

Figures 34 and 35 show a preferred version of a four-speed transmission, the transmission ratios of which are respectively 0.4 for the first gear, 1 for the second, 3 for the third and 9 for the fourth. The satellite carrier 263 is fixed here. Freewheels are placed between the so-called primary planet wheels driven by the sun of the input shaft, and there are two types of series of pinions: stepped planet wheels comprising so-called even pinions which drive suns of even speeds (the second and fourth) and stepped satellites comprising so-called odd pinions which drive suns of odd speeds (first and third). These stepped satellites are driven by the primary satellites via freewheels, which has the advantage that, when the selector 40 is in an intermediate position in which it could simultaneously connect two adjacent elementary transmissions, this does not cause any conflict. . This method makes it possible to produce transmissions according to the invention comprising only two freewheels regardless of the number of forward gears, which can therefore become very high.

The satellite carrier can be equipped with a freewheel allowing it to turn in the opposite direction to the motor direction. In this case, when the motor shaft rotates in the opposite direction, it drives the entire device, which constitutes a reverse gear. However, this only works if none of the transmission ratios of the elementary transmissions is less than 1.

Figures 36 and 37 show a preferred version of a transmission with eight forward speeds and two reverse speeds. One of the two springs holding the selector in the eighth forward gear position is not, as in the other figures, a compression spring, but a 4015 spring connected to the selector by a cable, and therefore operating under tension. This cable can slide in a sheath, which allows the adjustment control to be moved close to the user's hand or foot. It is thus possible to easily change the driving mode from "cruise" to "sport" for example, but also to change gears by a voluntary action by pulling more or less on the cable.

For a bicycle or any other system with acyclic motorization, it is possible to arrange on the path of the cable a damping means (not shown) so that the selector does not move during a cycle, but only according to the average value of the resistive torque over several cycles.

Two stepped planet gears are used for even speeds as in Figures 34 and 35, but a third optional planet gear drives the last gear pinion 252c2 and a first reverse gear pinion 252c1 which is mechanically connected to it by a wheel. free of direction opposite to that of the forward gears. This optional third satellite also provides engine braking.

Special arrangements and combinations

Figure 21 shows a transmission according to the invention in a particular application, similar to that shown in Figures 9 to 13, the crown of which is integral with a wheel 8 instead of being connected to the frame by a freewheel. This wheel can be immobilized by a brake or released in rotation by the operator, to have the same function as the freewheel previously described. It can also be a flywheel which, when the torque to which the transmission is subjected is less than a predetermined value, rotates at the speed of the primary shaft and the secondary shaft, but is driven in rotation at a speed different and in a direction of rotation which can also be different when the torque exceeds this value. This makes it possible to withstand jerks in the transmission. The flywheel can be braked permanently or on demand by a braking means to then regain the speed of rotation of the input and output shafts when the torque has become lower again. It can also be slowed down by an electric machine, which makes it possible to recover the energy it has stored. This electric machine can also function as an electric motor to supplement the torque supplied by the input shaft 2. Such a device can therefore serve as a braking means and as a SREC (Kinetic Energy Recovery System).

The device described in the previous paragraph is therefore a particularly advantageous damper in the sense that the energy it dissipates can be recovered. It can obviously include a higher number of elementary transmissions in order to be able to adjust the damping function very gradually. Those skilled in the art can cause the rotation of the input shaft by a linear movement such as that of a suspension spring of an automobile to recover the energy which in the prior art was lost. by the heating of the suspension components.

It is particularly advantageous to assemble in series or in parallel stepped transmissions according to the invention with other manual or automatic transmissions of the prior art or according to the invention.

In particular, a transmission according to the invention can be associated with a manual transmission allowing the user to choose an operating mode ranging, for example, from a bicycle or a "passenger" to "sport" car, while the transmission according to the invention then adapts the transmission ratio to the conditions encountered such as the nature of the terrain for example.

Two transmissions according to the invention or of other natures can be associated in parallel, sharing the same output shaft and having input shafts driven in rotation by different means, such as for example a crankset and a motor in the case of electric bicycles. When a transmission according to the invention comprises an epicyclic train, one of the components of this train can receive energy from one energy source and the other from another, as is known.

The transmissions according to the invention can also be assembled in parallel to drive two wheels of the same axle without the need for a differential.

A series assembly of stepped transmissions according to the invention makes it possible to have a number of transmission ratios which is the result of the multiplication of the numbers of elementary transmissions of each of the stepped transmissions.

There is a particular case which is that in which a transmission according to the invention drives a vehicle with an electric motor, because it is necessary to prevent a change in the transmission ratio causing an unforeseen change in the speed of movement of the vehicle, which could cause an accident. Several solutions are proposed.

– The first is to control the movement of the selector by a robotic mechanical means, as shown for example in Figure 6.

– A second consists in blocking the movement of the selector along the output shaft. Figure 5 shows a selector provided with a ball bearing 4001 whose lateral movement can be blocked by a device called blocker 4002. This blocker pivots around an axis 4003 and can be brought closer to the ball bearing 4001 to prevent any movement of the selector along the output shaft 3, or on the contrary move away to release such a movement. In a particular version, an elastic return (not shown) can support the clutch on the ball bearing 4001 to favor the positions of the selector in which it can only connect a single elementary transmission.

– A third, which is only possible if the motor is fitted with a variable speed drive, would be to measure - for example with a commercial infrared device, which is very inexpensive - the distance between the selector and one of its extreme positions. This measurement detects an elementary transmission change, which makes it possible to modify the rotational speed of the engine accordingly.

– A fourth consists in varying the position of the selector not according to the resistive torque but according to the engine speed by using a means of regulating the speed of rotation by centrifugal force. By increasing the speed of rotation of the secondary shaft much faster than the engine speed, a variation is obtained as a function of the resistive torque, since the variation of this torque almost always causes the engine speed to vary slightly, but this variation is less immediate if only the combination of a screw 31 and a selector 40 cooperating with this screw and driving the output shaft is used.

– A fifth method is to vary the position of the selector according to the speed of the output shaft by such a means of regulation by centrifugal force, which makes it possible to automatically vary the transmission ratio to obtain a constant speed of the output shaft.

– A sixth method consists in associating in series the device combining a screw 31 and a selector 40 described above with such a means of regulation according to the speed of rotation of the input shaft or the output shaft .

Those skilled in the art have many known means for regulating the speed of rotation by centrifugal force. It is possible, for example, to use the arrangements described in FIGS. 29 to 31, or a device similar to a James Watt ball regulator which controls the position of the selector instead of controlling a steam inlet valve.

All the figures represent toothed pinions with symmetrical teeth, but those skilled in the art will advantageously use toothed pinions with asymmetrical teeth for the gears always turning in the same direction. The teeth of these asymmetrical gears have a part cooperating with another pinion which forms a greater angle with the circumference of the pinion than the opposite part. It is in fact known that such gears offer a better ratio [torque transmitted/weight] and better efficiency in this particular case.

Apps

The main applications are:

- stepped gearboxes with fixed or variable ratios, manual or with automatic gear change,

- continuously variable transmissions with gears,

- centrifugal clutches without loss of energy,

- the torque limiters,

- the transfer of power to a plurality of drive wheels by a plurality of transmissions according to the invention, replacing the differentials,

- the combination of several energy sources, each being connected to the same output shaft by a transmission according to the invention, or by an elementary transmission of a transmission according to the invention,

- electric motors equipped with a transmission according to the invention to withstand any torque greater than that supplied by the motor during its normal operation, for example that which is necessary for starting or in the event of a mechanical overload,

- the recovery of energy during braking, by coupling the wheels to an energy storage means, by varying the transmission ratio to measure the stored energy and therefore the amount of braking,

- the real-time adaptation of the transmission ratio of wind turbines and tidal turbines to the optimal speed of their electric generator

- energy storage in flywheels of industrial machines and toys,

- the propulsion of bicycles and other vehicles or machines moved by a pedal or cranks,

- the automobile,

- winches, jacks and winches whose transmission ratio automatically adapts to the load torque,

- rotating tools.

The present invention is also a machine provided with a transmission according to the invention, or transmitting its power by such a transmission, or set in motion by such a transmission.

It is also the method of transmitting motion from an input shaft to an output shaft by using a mechanical transmission according to the invention.

Claims (10)

Mechanical transmission of movement from an input shaft (2) to an output shaft (3), called stepped transmission, comprising a plurality of means for transferring the movement of said input shaft to said output shaft, called elementary transmissions ( 2001, 2002 and 2003) each comprising an input which can be driven in rotation by said input shaft and an output which can be driven in rotation by said output shaft,
- at least two elementary transmissions capable of ensuring this motion transfer according to different transmission ratios,
- the input and the output of these two elementary transmissions being permanently mechanically connected, even when they do not transmit the torque from the input shaft to the output shaft,
- the stepped transmission being provided with at least one so-called selector clutch means (40) having the effect of putting an elementary transmission in a so-called connected configuration by mechanically linking its input to said input shaft or its output to said output shaft, or on the contrary to put it in a so-called disconnected configuration by mechanically disconnecting its input from said input shaft or its output from said output shaft,
- said selector being able to have different positions and such a change of position having the effect of connecting or disconnecting one of said elementary transmissions,
characterized in that said selector can assume a position in which it would simultaneously connect two elementary transmissions, because said stepped transmission is provided with a means called conflict management between elementary transmissions, which disconnects in this case one of these two elementary transmissions,
it being specified above and below that an output is said to be connected or engaged when the input shaft is mechanically linked in rotation to its input and that its output is mechanically linked in rotation to said output shaft, and disconnected or disengaged when at least one of these two mechanical connections is not made. Mechanical transmission according to Claim 1, characterized in that the said conflict management means consists in the fact that the said selector is provided with a means called the avoidance means modifying its position when this position would have the effect of two elementary transmissions being connected simultaneously, so that only one of these two elementary transmissions remains connected. Mechanical transmission according to Claim 1 or Claim 2, characterized in that the said conflict management means consists in the fact that at least one of the said connected elementary transmissions is provided with a one-way clutch called a freewheel (601). Mechanical transmission according to Claim 1, characterized in that the said selector can move along the said output shaft or the said input shaft, inside the mechanical elements which drive it or that it drives, as the case may be, the along their axis of rotation. Mechanical transmission according to Claim 1, characterized in that the said change of position of the said selector depends on the torque to which the said stepped transmission is subjected and on an elastic return. Mechanical transmission according to Claim 1, characterized in that one of its constituents has the possibility of elastic deformation. Mechanical transmission according to Claim 1, characterized in that the said input shaft and the said output shaft are aligned, and that one of the elementary transmissions is constituted by the direct engagement of the output shaft on the input shaft . Mechanical transmission according to Claim 1, characterized in that the said change of position of the said selector is slowed down by a damping means. Machine provided with a transmission according to claim 1 or transmitting its power by such a transmission, or set in motion by such a transmission. Method of transmitting movement from an input shaft (2) to an output shaft (3) by the use of a mechanical transmission called a stepped transmission comprising a plurality of means for transferring the movement of said input shaft to said output shaft, said elementary transmissions each comprising an input which can be driven in rotation by said input shaft and an output which can drive said output shaft in rotation,
- at least two elementary transmissions capable of ensuring this motion transfer according to different transmission ratios,
- the input and the output of these two elementary transmissions being permanently mechanically connected, even when they do not transmit the torque from said input shaft to said output shaft,
- the stepped transmission being provided with at least one so-called selector clutch means (40) having the effect of putting an elementary transmission in a so-called connected configuration by mechanically linking its input to said input shaft or its output to said output shaft, or on the contrary to put it in a so-called disconnected configuration by mechanically disconnecting its input from said input shaft or its output from said output shaft,
- said selector being able to have different positions and such a change of position having the effect of connecting or disconnecting one of said elementary transmissions,
characterized in that said selector can assume a position in which it would simultaneously connect two elementary transmissions, because said stepped transmission is provided with so-called conflict management means between elementary transmissions, which disconnects in this case one of these two elementary transmissions,
it being specified above and below that an output is said to be connected or engaged when the input shaft is mechanically linked in rotation to its input and that its output is mechanically linked in rotation to said output shaft, and disconnected or disengaged when at least one of these two mechanical connections is not made.