AU663346B2 - Modular transmission device and power unit so equipped - Google Patents

Abstract

The transmission has at least two sub-assemblies, each cooperating with a selection and control mechanism (29,31). The sub-assemblies comprise modular units (180a-d), each having a different axis (Da,Db,Dc) and linked together by a mechanical connecting member (2a,1b;2b,1c). The axes of the modules are arranged parallel to each other. In the case of three or more sub-assemblies, the mechanical connectors are arranged successively on alternate sides of the transmission. The sub-assembly modules are arranged in a straight or curved series configuration, and at least some of the modules may be coaxial.

Description

ANNOUNCEMENT OF THE LATER PUBLICATION OF AMENDEDCL I PCI (AND, WHERE APPLICABLE, STATEMENT UNDER ARTICLE 19)_ DEMANDE INTERNATIONALE PUBLIEE EN VERTU DU TRALTE DE COOPERATION EN MATIERE DE BREVETS (PCT) (51) Classification internationale des brevets 5 (11) Num~ro de publication internationale; WO 93/08419 F16H 37/04, B60K 17/08 Al (43) Date de publication internationale: 29 avril 1993 (29.04.93) (21) Num~ro de la demnande internationale: PCT/FR92/00986 (22) Date de d~p6t international: 21 octobre 1992 (21.10.92) Donn~es relatives i~ la priorit6: 91/13191 25 octobre 1991 (25,10.9 1) FR (71) D~posant (pour tous les Erats d~sign~s sauf US): 494~E-1N -A UOM TI\E mcH-Ne410&i-ES-HOLED! NG'S-B.-V [N L/N ,W A33 ~Ol3-tRtedm(~4 (72) Inventeur; et Inventeur/D~posant (US seulemtent) ANTONOV, Roue [BG/FR]; 18, rue de Berri, F-75008 Paris (FR).

(74) Mandataires: KEIB, Gerard; Bouju Derambure (Bugnion) 38, avenue de la Grande-Arm6e, F-75017 Paris (FR) etc.

7, (81) Etats d~sign~s: AU, BB, BG, BR, CA, CS, Fl, HU, JP, KP, KR, LK, MG, MN, MW, NO, PL, RO, RU, SD, US, brevet europ~en (AT, BE, CH, DE, DK, ES, FR, GB, GR, IE, IT, LU, MC, NL, SE), brevet OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, ML, MR, SN, TD, TG).

Publie Avec rapport de recherche iniern afionale.

A vec revendicalions tnodifi~es ei d~clarafion Date de publication des revendications inodifi~es et d~claration: 27 mai 1993 (27.05.93)

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(54) Title: MODULAR TRANSMISSION DEVICE AND POWER UNIT SO EQUIPPED (54)Titre: DISPOSITIF DE TRANSMISSION MODULAIRE ET GROUPE MOTO-PROPULSEUR AINSI EQUIPE (57) Abstract 213 Power unit comprising a motor (183), a clutch (184), a multi-ratio transmission (180a, 180b, 180c, 180d) and a differential (211) connected to drive wheels (213). The multi-ratio transmission consists of modules, with two ratios each (180a, 180b, 180c, 180d) disposed non-coaxially in order to make best use of the space available in the power unit for each given application. Application in automobiles in general.

(57) Abr~g6 Le groupe moto-propulseur I ea, 1 t IOUo comprend un moteur (183), un em- 14 brayage (184), une transmission mul- 183 14 ti-rapports (180a, 180b, 180c, 180d), et un diff~rentiel (211) reli& A des roues motnices (213). La transmission multi-rapports est constitu~e par des modules 5 deux rapports chacun (I180a, 180b, 180c, 180d) disposes de mani~re non coaxiale pour otimiser les cotes d'encombrement du groupe motopropulseur dans chaque application d~termin~e. Application A l'automobile en g~n~ral.

1- This invention relates to a modular transmission device.

H This invention also relates to a power and transmission unit for a vehicle or the like, provided with such a transmission device.

In modern motor vehicles, the power and transmission unit has to be as compact as possible.

This often raises problems, especially in the case of front-wheel drive vehicles, more specifically if the engine comprises more than four cylinders and if the transmission device offers numerous ratios and/or is of the automatically shifted type, because, then, the transmission device is necessarily more cumbersome.

An object of this invention is to remedy these drawbacks and more specifically to provide a transmission device offering a plurality of ratios while, in its preferred forms, being accommodable in a space having a shape which is a priori difficult to use.

According to one aspect of the invention there is provided a transmission device comprising at least two 0r:' transmission modules arranged in series along different axes, control means for controlling operation of each of j said modules selectively in one and the other of at least two transmission ratios, characterized in that a mechanical connecting means connects an input of one of the modules to an output of the other module whereby the modules are operatively in series, and in that the control means are distributed in the modules and allow L la substantially autonomous shifting of at least one of the modules between one and the other transmission ratio.

The invention thus allows the serial mounting of relatively small-sized modules in an arrangement that is freely selected in view of an optimized use of the available space in the motor compartment of the vehicle.

The invention also allows designs in which the output of the transmission device is in a favourable position for transmission towards each of the driving wheels of the vehicle.

i 7 o a il a 2 Preferably, the control means are distributed in the modules and allou substantially autonomous shifting between one and the other of the transmission ratios in at least some of the modules.

Thus, independently of the arrangement of the modules, there is no need to design a complicated control device which would have to be adaptable onto the modules.

This further reduces the design expenses which are specific for each type of vehicle which are to be equipped with the modular transmission device according to the invention.

This "substantially autonomous" control of some at least of the modules does not exclude that the modules receive from the outside simple information such as information which can be transmitted electrically, for example a "kick-down" control to force operation of the module in its mode of strongest speed-reduction when the driver of the vehicle completly depresses the accelerator pedal.

According to an other aspect of the invention, there is also provided a power and transmission unit for a motor vehicle or the like, comprising an engine and a transmission device according to the first aspect.

Other features and advantages of the invention will be apparent from the following description, related to non limiting examples.

In the accompanying drawings figure 1 is an axial sectional view of a transmission device according to the invention, wherein both end modules are shown in half view only figures 2 and 3 are diagrams of two examples of a power and transmission unit according to the invention for a front-wheel drive vehicle and '2 figure 4 is a diagrammatic perspective view of an other example of a transmission device according to the invention.

In the embodiment shown in figure 1, an engine 183, very partially and diagrammatically shown, drives an output shaft 1 by way of a clutch 184, for example of the 3 automatic type. Only the outer casing of clutch 184 is shown.

The output shaft 1 is simultaneousely the input shaft in a first tworatios module 180a having an output 2a which is coaxial with input 1 and opposed thereto. The output 2a is provided by a toothed wheel which meshes with an input toothed wheel Ib in a second-two ratios module 180b which is identical to the first module 180a except for differences which will be explained hereinbelow. An output 2b of module 180b meshes with an input Ic of a third module 180c having an output 2 which constituis the output of the transmission device formed by the modules 180a, 180b, 180c.

According to the invention, these modules instead of being coaxial, have respective axes Da, Db and Dc which are distinct from each other. In the example, said axes are parallel to each other and spaced apart from each other, whereby the axial length of the transmission device is almost identical to the axial length of anyone only of the three modules 180a, 180b and 180c.

Each module comprises in a respective casing 9, a combination of gears defining different transmission ratios between the input shaft 1, Ib or Ic, and the output 2a, 2b or 2.

In the example shown in figure 1, the combination of gears comprises, referring to module 180b, a planetary train -also called "epicyclic train"-. A sun gear 3 is rigidly connected to the input shaft Ib thereby to be driven in rotation by the input shaft lb. The sun gear 3 meshes with planet gears 4 mounted for free rotation on a planet carrier 5. The latter is fast with a central shaft 6 connected to the output 2b and having the same axis of rotation Db as the input shaft lb. There can be provided, for example, three planet gears 4 (only one of which is shown for the module Ib in figure 1) which are pivotally mounted about three axes E which are distributed about the axis Db.

The teeth of the planet gears 4 moreover mesh with the inner teeth of a ring gear 7, which is also centered on axis Db and rotatable thereabout.

As is wellknown, the transmission ratio between the input Ib and the output 2b depends upon mechanical couplings which are achieved between the rotary elements (sun gear 3, planet carrier 5 and ring gear 7) of the planetary train. In the example shown, said mechanical couplings are selectively performed between the planet carrier 5 and the ring gear 7. A free wheel 8, mounted, between the stationary casing 9 of the transmission and the outer edge of the ring gear 7, prevents the ring gear 7 from rotating in a reverse direction with respect to the input shaft lb.

A multidisks clutch is mounted between the ring gear 7 and the planet carrier 5 for providing selective coupling between these two rotary elements. This clutch comprises a stack of axially slidable disks 14, First disks 14 of the stack are connected for common rotation with the ring gear 7. To this end, said disks 14 are provided on their external edge with external teeth 18 which are seated in internal splines 19 of the ring gear 7 which are parallel to axis D. The splines 19 are defined between fingers 20 belonging to the ring gear 7.

Second disks 15 of the stack, each of which is located between two first disks 14, are connected for common rotation with the planet carrier 5. To this end, said second disks are provided on their inner edge with inner teeth 21 which are seated in external splines 22 extending parallel to axis Db and belonging to the planet carrier 5. The splines 22 allow for axial sliding of the disks 15 with respect' to the planet carrier The stack of disks 14, 15 can be selectively clamped by a mechanism mounted on the central shaft 6. Said mechanism comprises a plate-shaped clamping pusher 17, biasing springs 29 (only one of which is shown) distributed about shaft 6, centrifugal weights 31 and a carrier 30 for the weights. The carrier 30 is fast with the central shaft 6, whereas the clamping pusher 17 is axially between the carrier 30 and the stack of disks 14, 15, and is connected for commom rotation with the shaft 6 while being axially slidable thereon.

The periphery of the surface of the clamping pusher 17 is in contact with the disk 14 or 15 (15 in the example) forming one end of the stack, whereas the other disk forming the other end of the stack is in contact with the planet carrier 5. Thus, when the clamping pusher 17 is axially urged towards the planet carrier 5 with a sufficient thrust, the stack of disks 14, 15 is tightened together, and the ring gear 7 and the planet carrier 5 are coupled together. The biasing springs 29 are mounted between the planet carrier 5 and the clamping pusher 17.

The thrust produced by said springs 29 tends to urge the clamping pusher 17 axially away from the planet carrier and thus to untighten the stack of disks 14, Each weight 31 comprises a nose 33 a portion of which, having an axial displacement component, engages the I pusher 17. The nose 33 operates as a cam defining the spacing between the pusher 17 and the carrier 30 which is axially stationary with respect to the planet-carrier 5. The weights 31 are driven in rotation at the speed of rotation of the output 2 and thus apply to the pusher 17, as soon as the thrust of the springs 29 is overcome, a thrust which is a monotonously increasing function of the speed of rotation of the output 2i If the speed of rotation of the planet carrier and its shaft 6 is low or even equal to zero, the weights 31 are in the rest position shown in the lower part of module 180b, adjacent the bottom of the respective slits 32. This is due to the action of the springs 29, which repell the pusher 17. When this speed of rotation increases, the weights 31 leave their rest position under the action of the centrifugal force. The noses 33 of the weights are retained by a projection 36 at the periphery of the clamping pusher 17, whereby the weights 31 pivot as shown in the upper part of module 180b. As a consequence of this pivotal movement, the noses 33, whose portion engaging the pusher 17 has an axial displacement-component, axially e 6 space apart the clamping pusher 17 from the carrier 30. As the carrier 30 is rigidly connected to the central shaft 6, the clamping pusher 17 is urged towards the planet carrier against the action of the biasing springs 29.

Thus, beyond a predetermined speed of rotation of the planet carrier 5, the centrifugal force which appears in the weights 31 raises the weights 31 as shown in the upper part of module 180b, whereby the weights 31 urge the pusher 17 against the stack of disks against the action of the biasing springs 29.

On the other hand, an axial thrust bearing 137 is mounted between the ring gear 7 and the pusher 17.

In addition, the teeth of the sun gear 3, the planets 4 and the ring gear 7 are of the helical type. This i 15 is classical for cancelling the noise of operation of the I gears. It is known however that the helical teeth produce, when in operation, an axial thrust on the parts provided i with said teeth. As a consequence, during the speed-reducing i operation, the ring gear 7 generates an axial thrust FAC which is transmitted to the pusher 17 by the axial thrust bearing 137, and which is proportional to the torque on the input shaft 1.

The direction of inclination of the helical teeth is so selected that the thrust FAC is added to the thrust of the springs 29.

The difference between the axial thrust produced by the weights 31 on the pusher 17 and the contrary thrust produced on the same pusher 17 by the springs 29 together t.i with the axial thrust'FAC constitutes, if this difference is positive, a clamping force applied to the stack of disks 14, Depending upon the torque to which the input shaft Ib is subjected, this clamping force will be high enough or not for coupling the planet carrier 5 to the ring gear 7 of the epicyclic train. If the torque applied to the input shaft Ib is relatively low by comparison with the speed of rotation of the output 2b, the clamping force will

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I 7 be high enough, and the planet carrier 5 will be fast with the ring gear 7. In this situation, the planets 4 cannot roll on the ring gear 7 and accordingly cannot rotate on themselves about their own axis E. As a consequence, the planets 4 are also unable to roll onto the sun gear 3.

There is thus a coupling for common rotation between the shaft Ib and the planet carrier 5, and there is accordingly a direct drive connection between the input shaft lb and the output 2b of the module 180b.

By contrast, if the torque applied to the input shaft Ib is relatively high by comparison with the speed of rotation of the planet carrier 5, the clamping force applied to the stack of disks 14, 15 is not high enough for coupling together the ring gear 7 and the planet carrier In this case, as the planet carrier 5 tends to remain stationary under the action of the load to be driven by the output 2b, the planets 4 tend to operate as movementreversal devices, that is to say to make the ring gear 7 rotate in a direction contrary to the direction of rotation of the shaft lb. This is however prevented by the free wheel 8, whereby the ring gear 7 remains stationary with respect to the casing 9, and the planet carrier 5 rotates i at a speed which is intermediate between the speed of the input shaft Ib and the speed, equal to zero, of the ring gear 7. In this case, the module 180b operates as a speedreducing gear.

Between these two situations, there is an intermediate situation, in which the torque applied to the' input shaft lb has a medium magnitude by comparison with iI 30 the speed of rotation' of the planet carrier 5. This corresponds to a predetermined range of torque magnitudes of the shaft Ib for each given speed of rotation of the planet carrier 5, and to a range of speeds of rotation of the planet carrier 5 for each torque magnitude of the shaft lb. In such a situation, the clutch 14, 15 tends to remain in any pre-existing condition, that is to say to remain in the grip condition when it is in the grip condition and to 8 remain in the slip condition when it is in the slip condition.

More specifically, when the clutch is tightened, no effort is transmitted between the teeth of the planets 4 and those of the ring gear 7 and, as a consequence, the axial reaction FAC disappears. In other words, once shifting up has occured, a subsequent shifting down of the module will need a substantial decrease of the speed of rotAtion or a substantial increase of the torque on the shaft lb. As soon as the module has shifted down, the axial thrust FAC appears again and, consequently, stabilizes the operation in the speed-reducing condition.

In other words, each time the operating condition of the clutch changes, the axial thrust FAC varies in the direction stabilizing the transmission ratio just activated.

Both modules 180b and 180c can be strictly identical, even as to their functional settings. However, still in the illustrated example, the module 180a differs from both modules 180b and 180c in that the weights 31 are far less numerous in module 180a, e.g. three or four weights only instead of thirty or fourty. Between the weights of module l10a, there are compression springs 158 axially urging the pusher 17 in the direction of clamping of the clutch, in other words in the same direction-as the weights 31 when they are subjected to the centrifugal force.

By contrast, the springs 29 tending to untighten the clutch are suppressed.

i Operation is as follows first, clutch 14, 15 of module 180a is tightened by the springs 158 and the SIclutches 14, 15 of the modules 180b, 180c are disengaged by springs 29 so that the module 180a works in direct drive and the modules 180b and 180c work as speed-reducing gears. Thus, among modules 180b and 180c, the module 180b is the one in which the rotatory speed is higher and the torque transmitted is the lower. It is therefore this module which first reaches the conditions in which its weights 31 become able to engage clutch 14, 15 so that this module shifts up into 9 direct drive. This reduces the torque transmitted to the next module 180c, but not its rotatory speed which is determined by the speed of the output 2. Therefore, this speed must increase so that, assuming the torque to be cotitant, the weights of the module 180c will s.,ift the latter into direct drive, so that the transmission will operate in a third ratio, which is the direct-drive ratio through the whole transmission 180a, 180b, 180c.

When the input module 180a, due to the torque present on shaft 1, works as a speed-reducing gear, the modules 180b and 180c still operate as described hereinabove, with three exceptions since the torque present on shaft Ib is increased, the shift from first to second requires a greater force on the part of the weights 31 of module 180b, and it will theirfore be performed at a higher engina speed for the same reason, the shift from second to third will require a greater force on the part of weights 31 of module 180c, and consequently it will be performed at a higher speed of the output shaft 2 once this shift from second to third is performed, the engine speed will increase until the driving torque decreases sufficiently (beyond the engine speed of rotation which corresponds to the maximum torque, the available torque decreases as a function of the engine speed of rotation) for the springs 158 to cause the shift of the input module 180a to direct drive, which then constitutes a fourth transmission ratio.

An automatic transmission for vehicles has thus been achieved, which operates either with three ratios and relatively low engine speeds in normal driving, or in sport driving with four ratios of which the first three are different from the first two of normal driving, making the engine to run at speeds close to maximum power, which optimizes performance.

The fonction of the weights 31 of module 180a is to increase, when the speed of rotation of the engine increases, the torque threshold at which the module 180a will shift from direct drive operation to speed-reducing operation. This avoids that the module 180a shifts to the speed-reducing operation while the rotating speed of the engine is already relatively high.

Thanks to the modules and to their arrangement, the transmission device is efficient, simple and especially short in the axial direction. The illustrated arrangement could for example be favourable for a power and transmission unit adapted for a front wheel drive vehicle having a longitudinaly disposed engine, ahead of or behind the driving axle.

This type of transmission could also be used with an engine the cylinders of which would be disposed horizontally substantially in the same plane as the axes Da, Db and Dc of the modules.

Since the modules comprise control means in themselves (weights 31, springs 158, springs 29, axial thrust bearing 137), there is no necessity of realizing a control device which would be adaptable on the array of modules. Thus, essentially, the only need consists in realizing a plurality of identical or similar modules and to secure them to each other, for example by securing to each others the casings 9.

Figure 2 shows an other example of a power and transmission unit according to the invention.

The engine 183 is disposed transversely, in other 4 words parallel to the axes of the driving wheels 213, each of which is connected to one of the outputs of a differential device 211; The latter can be conventional in its principle. The input of the differential 211 is provided by the output 2 of the transmission device.

The transmission device comprises four modules 180a, 180b, 180c and 180d instead of three in the previous example. The modules 180a, 180b and 180c are identical to those of figure 1, and the module 180d is identical to the modules 180b and 180c.

i 11 Both modules 180a and 180b are coaxial mutually and with the engine 183. In other words, the output 2a of module 180a is the same as the input Ib of module 180b.

Similarly, the modules 180c and 180d are coaxial so that the output 2c of module 180c is the same as the input Id of module 180d. The common axis of modules 180a and 180b is parallel to that of modules 180c and 180d, and spaced apart therefrom. The output 2b of module 180b is provided by a toothed wheel meshing with an other toothed wheel providing the input Ic of module 180c.

Thanks to this arrangement, the engine 183, the clutch 184 and the transmission device are easily accomodated between the driving wheels 213, whereas there is further obtained the advantage that the differential device 211 can be located at equal distance between both wheels.

The example of figure 3 may be preferred if the engine is axialy longer, e.g. in the case of an engine having six cylinders disposed in line.

There is again the transmission device having four modules 180a, 180b, 180c and 180d, the output of which is also the input of the differential device 211.

The arrangement of the modules 180a and 180b with respect to each other is identical to that of figure 1.

The output 2b of module 180b is provided by a toothed wheel which meshes with the toothed wheel providing the input Ic of module 180c. The module 180c and the module, 180b are arranged on either side of the plane of the toothed wheels Ic and 2b. The general arrangement of the modules 180c, 180d and of the differential device 211 is identical to that of figure 2.

In the example of figure 4, the four modules 180a-180d are disposed in a similar fashion as that illustrated in figure 1 for modules 180a-180c, but the axes Da, Db, Dc and Dd, instead of being coplanar, are arranged along a circle, in other words they are four generating lines of a same virtual cylinder. The modules 180a and 180b are connected to each other as those of figures 1 and 3.

11~~ -ii i 12 The modules 180b and 180c are connected to each other as those of figure 1 but this is difficult to see in figure 4 as a consequence of the point from which the perspective view is seen. The modules 180c and 180d are connected to each other by gears comprising an intermediate gear 181, whereby the toothed wheels Id and 2c providing the input of module 180d and respectively the output of module 180c, can have a shorter diameter, thereby not to interfere with the toothed wheels providing the output 2a of module 180a and the input Ib of module 180b.

Of course, the invention is not limited to the examples described in and illustrated.

The modules could be all identical, including the input module 180a thereby to provide an automatic transmission permanently operating with for example four ratios (three modules) or five ratios (four modules).

Although it is preferred that the operation of the modules be as autonomous as possible, it is nevertheless possible to provide means for supplying them with specific information or controls in predetermined conditions for example in case of abrupt acceleration or braking.

Neither the way in which the modules are secured together, nor the way in which the transmission device is secured to a vehicle frame, nor the possible hoods that can be provided for protecting the connecting gears are shown.

Such additional means are easily conceavable by one having, an ordinary skillness in the art.

It is possible to give to the modules an arrangement such that the axes of the modules form angles between them.

Claims (12)

1. A transmission device comprising at least two transmission modules arranged in series along different axes, control means for controlling operation of each of said modules selectively in one and the other of at least two transmission ratios, characterized in that a mechanical connecting means connects an input of one of the modules to an output of the other module whereby the modules are operatively in series, and in that the control means are distributed in the modules and allow substantially autonomous shifting of at least one of the modules between one and the other transmission ratio.

2. A transmission device according to claim 1, characterized in that said modules have parallel axes.

3. A transmission device according to claim 1 or 2, characterized in that it comprises at least three modules mounted side by side with parallel axes and mechanically connected in series by mechanical connecting means which are inserted between the successive modules.

4. A transmission device according to claim 3, characterized in that the modules mounted side by side form a rectilinear array.

A transmission device according to claim 3, characterized in that the modules mounted side by side form an arcuate array.

6. A transmission device according to claim 1 or 2, Z. characterized in that at least one of said at least two t 14 modules is coaxially connected with at least one third module.

7. A transmission device according to one of claims 1-6, characterized in that at least one of the modules comprises a differential gear having three rotating elements carrying intermeshed helical teeth, a free wheel preventing one of the rotating elements from reverse rotation, a friction clutch for selectively coupling two rotating elements to each other, and a means for biasing the clutch towards tightening thereof, one of the three rotating elements being axially movable for transmitting to the clutch, in the direction of release thereof, an axial thrust generated by meshing of the helical teeth under load, the arrangement being such that the axial thrust is at least in part cancelled when the clutch is in the coupled condition. 15

8. A transmission device according to claim 7, characterized in that the means for biasing the clutch comprises centrifugal weights.

9. A transmission device according to claim 7 or 8, characterized in that the means for biasing the clutch comprises a resilient means.

A power and transmission unit for a motor vehicle or the like, comprising an engine and a transmission device in accordance with any one of claims 1-9.

11. A transmission device substantially as herein described with reference to Figure 1 or Figure 4 of the accompanying drawings. I JS 444 4 4 f/U I r j 18 I f i a ii 1 ;II 1 i i f a I 1 i f i i :t i i ii e iii 15

12. A power and transmission unit substantially as herein described with reference to Figure 2 or Figure 3 of the accompanying drawings. DATED this 20th Day of July, 1995. ANTONOV AUTOMOTIVE FAR EAST B.V. Attorney: WILLIAM S. LLOYD Fellow Institute of Patent Attorneys of Australia of SHELSTON WATERS NT\ cj I j