FR3053421A1 - ROTATION COUPLING DEVICE - Google Patents

Abstract

The present invention relates to a hydraulic coupling device between a first shaft (10) and a second shaft (20) coaxial with each other. The device comprises a device forming a positive displacement pump operating in closed circuit, actuated by the relative rotation between a first rotor (11) rotatably connected to the first shaft (10) and a second rotor (21) integral in rotation with the second shaft (20). ). An adjustment of the flow rate or of the fluid pressure in the closed circuit thus provides control of the flow resistance in the closed circuit, and thus the relative rotation between first (11) and second rotor (21), thus realizing a control of the torque transmitted between said shafts. The invention applies in any field where it is necessary to couple in rotation two shafts solidarity. The invention applies in particular in the automotive field. For example, the pump comprises a flywheel on a crankshaft, in which radial pistons are actuated by an eccentric mounted on another crankshaft.

Description

© Publication number: 3,053,421 (to be used only for reproduction orders) (© National registration number: 16 56256 ® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY

COURBEVOIE © Int Cl ⁸ : F16 D 31/02 (2017.01), F 02 B 73/00

A1 PATENT APPLICATION

©) Date of filing: 30.06.16. © Applicant (s): ALTRAN TECHNOLOGIES - ALTRAN (© Priority: Public limited company - FR. @ Inventor (s): PRIEUR GIUSEPPE, LEO and FAURE NICOLAS. (43) Date of public availability of the request: 05.01.18 Bulletin 18/01. ©) List of documents cited in the report preliminary research: Refer to end of present booklet (© References to other national documents © Holder (s): ALTRAN TECHNOLOGIES - ALTRAN related: Anonimous society. ©) Extension request (s): © Agent (s): PONTET ALLANO & ASSOCIES.

(64) ROTATING COUPLING DEVICE.

FR 3 053 421 - A1 (g / 2 The present invention relates to a hydraulic coupling device between a first shaft (10) and a second shaft (20) coaxial with each other. The device comprises a device forming a positive displacement pump operating in circuit closed, actuated by the relative rotation between a first rotor (11) integral in rotation with the first shaft (10) and a second rotor (21) integral in rotation with the second shaft (20) .Adjustment of the flow rate or of the fluid pressure in the closed circuit thus performs a control for adjusting the flow resistance in the closed circuit, and therefore for the relative rotation between first (11) and second rotor (21), thus achieving control of the torque transmitted between said shafts .

The invention applies in any field where it is necessary to couple two shafts in rotation in solidarity. The invention applies in particular in the automotive field. For example, the pump includes a flywheel on a crankshaft, in which radial pistons are actuated by an eccentric mounted on another crankshaft.

i "Rotating coupling device"

The present invention relates to a hydraulic coupling device between a first shaft and a second shaft coaxial therebetween. The device comprises a device forming a positive displacement pump operating in a closed circuit, actuated by the relative rotation between a first element called the first rotor and a second element called the second rotor, in which the first rotor is integral in rotation with the first shaft and the second rotor. is integral in rotation with the second shaft. The device further comprises a device for controlling the flow rate or the fluid pressure within said closed circuit, thus carrying out a control for adjusting the flow resistance within the closed circuit, which controls the resistance to relative rotation between the first rotor and the second rotor, thereby achieving control of the torque transmitted between said first and second shafts.

The invention applies in any field where it is necessary to couple two shafts in rotation in solidarity. The invention applies in particular in the automotive field. For example, the pump includes a flywheel on a crankshaft, in which radial pistons are actuated by an eccentric mounted on another crankshaft.

State of the art

In the field of mechanical coupling of two rotating shafts, it is known in particular to use adhesion clutches or hydraulic torque converters. However, the friction clutch has the disadvantages of a limited lifespan and the propagation of dust due to wear of the disc (s), which requires a closed enclosure. In addition, the torque converter has the disadvantage of sliding between the two shafts so that it does not allow two shafts to be rotatably joined together.

In the automotive field, it is known to deactivate the fuel supply in one or more cylinders in order to reduce fuel consumption and reduce the emission of polluting gases.

However, it is keen to further reduce fuel consumption and polluting gas emissions.

It is also known to connect two individual engines by means of a coupling device, of the friction clutch type comprising one or more discs, placed between the two crankshafts of the engines to reduce mechanical friction. However, as mentioned above, the friction clutch has the disadvantages of a limited lifespan and propagation of dust due to wear of the disc (s) which requires a closed enclosure. In addition, the integration of these solutions increases the overall size, at least longitudinal, of the assembly compared to the traditional architecture of the motors.

The invention aims to provide a coupling device for limiting the increase in size compared to known devices. It also aims to ensure the transmission of torque between the two crankshafts.

Statement of the invention

At least one of the objectives is achieved with a hydraulic coupling device between a first shaft and a second shaft coaxial therebetween. The device comprises a device forming a positive displacement pump operating in a closed circuit, actuated by the relative rotation between a first element called the first rotor and a second element called the second rotor, in which the first rotor is integral in rotation with the first shaft and the second rotor. is integral in rotation with the second shaft. By positive displacement pump is meant a pump characterized by the proportionality between its flow rate and its rotation speed, whatever the discharge pressure. The device further comprises a device for adjusting the flow rate or the fluid pressure within said closed circuit, thus carrying out a control for adjusting the flow resistance within the closed circuit, which controls the resistance to relative rotation between the first rotor and the second rotor, thereby achieving control of the torque transmitted between said first and second shafts.

According to a family of embodiments, the coupling device forming the hydraulic pump comprises at least one piston arranged radially around the axis of rotation of the shafts. Preferably, the device comprises several pistons. The first rotor includes an eccentric member extending in an axial direction parallel to the axis of rotation. The eccentric element is attached to one end of the first shaft. The second rotor includes a flywheel mounted fixedly and coaxially at one end of the second shaft, surrounding the eccentric element. The flywheel extends in a plane perpendicular to the axis of rotation. The flywheel contains the radial piston (s).

According to a first embodiment, the eccentric element is a crank pin extending along an axis parallel to the axis of rotation of the shafts and is fixed to one end of the first shaft. The device further comprises connecting rods so that each connecting rod is connected, at a first end, to the crankpin and at a second end, to a piston. The connecting rods connect the first rotor to the second rotor. When the first shaft is in rotation, the arrangement of the crank pin and the connecting rods makes it possible to raise and lower the radial pistons in the flywheel, and thus makes it possible to circulate the hydraulic fluid.

According to a second embodiment, the eccentric element is a section of a shaft having a cylindrical circumference of variable diameter along its perimeter. The eccentric has a cam-shaped profile and is arranged coaxially on an axial end of the first shaft. The radial pistons then bear on the circumference of the eccentric element. When the first shaft is in rotation, the eccentric element makes it possible to raise and lower the radial pistons in the flywheel, and thus makes it possible to circulate the hydraulic fluid.

The device according to the invention makes it possible both to transmit the couplet and to couple two shafts together in rotation. The device can for example ensure the clutch function between a drive shaft and a receiving shaft. The device according to the invention also makes it possible to couple two engine shafts, for example two crankshafts of two separate engines or two crankshafts of the same engine.

According to a preferred embodiment of the invention, for example within this family, at least one of the abovementioned objectives is achieved with a device for coupling in rotation between a first half-crankshaft and a second coaxial half-crankshaft between them. Half crankshaft is understood to mean a crankshaft for an engine intended to be coupled by mechanical engagement with another crankshaft of the same engine or of another engine. The coupling device makes it possible to decouple the half-crankshafts, deactivating part of the engine to reduce fuel consumption, pollutant gas emissions and mechanical friction at the same time when the engine is slightly stressed by the driver. It also makes it possible to connect two crankshafts to set in motion an inactive engine so that the two crankshafts rotate at the same speed of rotation, and thus obtain a larger displacement engine thanks to the combination of the two engines.

According to a preferred embodiment, the coupling device is placed between a journal of the first half-crankshaft and a crankpin of the second half-crankshaft, the coupling device being both connected to said journal and to said crankpin to drive in rotation the two half-crankshafts. The coupling device on the one hand is inserted into said crankpin, to form a crankshaft elbow, and on the other hand forms a bearing for said journal. This arrangement makes it possible to reduce the space requirement, in particular axial, of the coupling device compared to the prior art. It is even possible not to increase the axial length of an engine compared to an engine equipped with a traditional crankshaft.

According to one embodiment of the invention, the coupling device comprises a radially eccentric element integral in rotation with the first half-crankshaft. By eccentric is meant a section of a shaft having a cylindrical circumference of variable diameter along its perimeter. The eccentric has a cam-shaped profile and is arranged coaxially on an axial end of the first half-crankshaft, the axial end of the first crankshaft facing the second half-crankshaft. The eccentric element is mounted on the axial end of the first half-crankshaft. Preferably, the axial end of the first half-crankshaft is a journal; the eccentric element is then mounted on the axial face of the pin.

The coupling device comprises a flywheel integral in rotation with the second half-crankshaft and arranged coaxially around the eccentric element. Said flywheel comprises one or more coupling groups each including at least a first cylinder, called the working cylinder and a second cylinder, called the working cylinder, which are arranged in a substantially radial manner around the axis of rotation of the half-crankshafts. The working cylinders, for the same coupling group, communicate with each other by a sealed circuit containing a hydraulic fluid. The fluid can be considered incompressible. The fluid circulates between the working cylinders by a hydraulic conduit. The circuit formed is thus closed. According to a preferred embodiment, the working cylinders and the conduits are arranged in the flywheel of the coupling device. In particular, the cylinders form bores opening towards the eccentric element.

The working cylinders each contain a movable piston, which is arranged so that it can be moved radially relative to the axis of rotation by pressing against the eccentric when the first half-crankshaft and the second half-crankshaft have a relative rotational movement relative to each other. The movement of the piston on the eccentric makes it possible to compress and relax successively and alternately the fluid in the associated cylinder. Preferably, each working cylinder contains an elastic return spring which forces the piston to bear against the profile of the eccentric.

According to a preferred embodiment, the second half-crankshaft is constantly active during the operation of the engine. At low loads from the driver, only the second half-crankshaft is active. The flywheel, rotated by the second half-crankshaft, is rotatably mounted on the journal of the first half-crankshaft which is adjacent to the second half-crankshaft. When the flywheel is rotated by the second half-crankshaft, each piston slides in its cylinder according to the profile of the eccentric, that is to say as a function of the residual distance between the radius of the eccentric and the inner surface of the circular bore of the flywheel, in the radial direction of said piston.

According to the invention, the eccentric has at least one radially increasing profile, said rising profile, and at least one radially decreasing profile, said descending, which are arranged successively and alternately on the periphery of the eccentric. By rising profile of the eccentric element is meant an increase in the radius of the eccentric element along its perimeter. By descending profile of the eccentric element is meant a reduction in the radius of the eccentric element along its perimeter. The rising and falling profiles are arranged so that:

when the increasing profile pushes one of the pistons of said group in an upward movement, then constituting a rising piston, said upward movement pushes the other piston of said group towards the eccentric in a downward movement via said hydraulic fluid, constituting then a descending piston; and said decreasing profile allows the downward movement of said descending piston;

Said flywheel further comprises at least one device for adjusting a passage section of said hydraulic circuit between said first and second cylinders, which is controlled to selectively perform:

an opening of said passage section, authorizing the passage of the fluid from the first cylinder to the second cylinder and vice versa, a partial or total closure of said passage section, forming a so-called braking section which brakes or blocks said passage of fluid, and by consequently the displacement of the rising piston, which then opposes the rotation of the increasing profile, thus producing braking or blocking the rotation of the eccentric relative to the flywheel.

Preferably, the flywheel carries, for each working piston, a retaining finger which can be moved between:

a holding position in which it cooperates by mechanical engagement with an accident in the shape of the piston to retain said piston in the high position, and, a released position in which it leaves said piston free in translation in its cylinder.

For example, the accident of form is a throat. The groove and retaining finger assembly makes it possible to retain the working pistons in the flywheel, and thus prevent them from unnecessarily striking the eccentric when the first half-crankshaft is inactive.

According to the invention, the flywheel comprises, for one or more coupling groups (and preferably all), one or more so-called reserve cylinders which comprise an elastic enclosure communicating with the hydraulic circuit of said group, so as to be able to, automatically or selectively maintain sufficient pressure in said hydraulic circuit. The reserve cylinders also make it possible to keep a reserve of fluid to compensate, for example, for possible leaks.

According to a particular embodiment, each reserve cylinder can admit hydraulic fluid coming simultaneously from a first and from a second cylinder of the same group, thus authorizing a simultaneous ascent of said first and second pistons. The raising of the pistons makes it possible to avoid friction of the latter on the profile of the eccentric when the engine operates with a single crankshaft.

Preferably, the at least one reserve cylinder is closed at one end and contains a movable piston resting elastically on said closed end. According to a preferred embodiment, all the reserve cylinders are closed. For example, the movable piston is a plate provided with a sealing segment. The movable piston is preferably supported by means of a helical compression spring.

According to a preferred embodiment, each coupling group comprises exactly one reserve cylinder and two working cylinders.

According to the invention, the adjustment device comprises, for one or more working rolls:

- a sealing ring fixed to the steering wheel and which includes a communication opening between the cylinder and the hydraulic circuit of the coupling group,

- A movable closure rod comprising a contact surface, forming a bearing surface capable of coming into complete sealed contact with said communication opening of the ring, cooperating with the opening of the closure ring in order, depending on its position, to open or more or less close said opening and thus determine the braking section; that is to say that the braking section is formed by the passage section between said communication opening of the ring and the contact surface of the rod, and the value of this passage / braking section is adjusted by the position of said movable closure rod relative to the communication opening of the ring,

- an adjustment screw mounted in the steering wheel, on which the shutter rod bears or is fixed.

Preferably, an adjustment device is provided for each working cylinder.

According to a preferred embodiment, the adjustment screw is controlled in rotation to move the closure rod in translation relative to the opening of said closure ring, and thus adjust said passage section. For example, the adjusting screw is linked to the steering wheel by a helical connection of the screw-nut type. The adjustment device makes it possible to control the flow rate of the fluid and in particular to propose an outlet flow rate lower than the intake flow rate ensuring a non-return function. It makes it possible to control the sliding speed of the piston in its cylinder, and thus to increase the force of the pistons on the eccentric in order to put in rotation the first half-crankshaft.

Preferably, the adjusting screw carries the closure rod by a movable link in translation under the effect of the circulation of the fluid, between:

a position in abutment against the screw, determined by the position of the adjusting screw, in which the position of the shutter rod vis-à-vis the shutter ring determines a first section for passage of the fluid, called braking, o a position released from the screw in which the position of the closure rod vis-à-vis the closure ring determines a second fluid passage section, called the intake section, larger than the first passage section, thus producing a two-position valve which allows, for the same adjustment of the adjusting screw:

o in the direction of the cylinder outlet, an outlet flow regulated by the position of the adjusting screw, and o in the direction of the entry into the cylinder, an inlet flow greater than the outlet flow.

Preferably:

o the opening of the closure ring has a flared shape (for example conical) towards the working piston, o the adjusting screw is outside the cylinder, and o the closure rod passes through said opening and has on the side of the piston an enlarged end carrying the contact surface (for example a portion of a sphere or cone) which cooperates with the flared shape of the opening of the closure ring. This embodiment of the adjustment device has the additional advantage of being compact.

Preferably, the closure ring is freely mounted in one end of the working cylinder, and is held there by an elastic return element of a stiffness, and in particular preload, determined to allow, beyond a pressure determined in the cylinder, a displacement of said ring towards the outside of the cylinder so as to release an additional leakage section. For example, the ring is fitted into the cylinder at one end opening into a conduit connecting another cylinder. The elastic return element is for example a leaf spring through which the rod passes. An additional leakage section can be released around said ring.

According to the invention, the adjusting screw is arranged radially on the periphery of the flywheel, and the coupling device comprises at least one stationary maneuver in rotation which surrounds the flywheel and is arranged to translate in a direction parallel to the steering wheel axis. The operating element has at least one shape cooperating with at least one crank pin or a lug protruding from said adjustment screw, for screwing or unscrewing said adjustment screw according to said translation. The operating element can be rotated to adjust its angular position. For example, the operating element is a fork.

According to a preferred embodiment, the operating element comprises a crown which has on its outer circumference: o on the one hand at least a portion of toothing (for example straight) which cooperates with a pinion (or for example a screw without end) to modify the angular position of the crown, and o on the other hand at least a portion of thread (for example helical according to a screw-nut mechanism) which cooperates with the engine block to transform said rotation into axial translation, thus achieving the operation of the adjustment screws.

The crown allows all the screws to be actuated simultaneously.

According to another embodiment, the pinion can be replaced by an endless screw and the threading portion has a helical threading portion so as to produce a screw-nut mechanism.

According to the invention, the coupling device further comprises a dog clutch device arranged to perform a coupling by mechanical engagement of the two half-crankshafts. Preferably, the dog clutch device comprises, on the one hand, one or more latches movable in translation and fixed in rotation relative to the steering wheel, which are arranged to cooperate with accidents of complementary shape carried by an axial face of the eccentric. For example, locks and accidents of complementary shape are teeth. On the other hand, the dog clutch device comprises one or more control pins which cooperate with an operating member movable in translation to control the dog clutching or the clutch clutch under the effect of the translation of said operating member. The dog clutch device secures the torque transmission between the two half-crankshafts.

Preferably, the operating element of the dog clutch device is the same as that for the adjusting screws and / or that of the control of the holding device, or possibly another which is independent of it. According to a preferred embodiment, the operating element is the crown. This solution has the advantage of being compact.

Preferably, the dog clutch device comprises one or more arms which carry the control pins and control the fingers holding the working pistons.

According to another aspect according to the invention, there is provided an engine, or vehicle comprising such an engine, comprising at least a first and a second half-crankshaft coupled by a coupling device according to the characteristics described above.

Description of the figures and embodiments

- Figure 1 shows a block diagram of a hydraulic coupling device according to the invention;

- Figure 2 shows a block diagram of a hydraulic coupling device according to one embodiment;

- Figure 3 shows a low engine sectional view and comprising a coupling device arranged between two half-crankshafts;

- Figure 4 is an exploded view of an embodiment of the coupling device, located between two half-crankshafts, comprising a clutch device, a flywheel, an eccentric and working pistons arranged radially around the eccentric ;

- Figure 5 is a cross-sectional view showing part of the elements of the coupling device comprising, according to one embodiment, three coupling groups arranged in a flywheel, said flywheel surrounding an eccentric of triangular shape;

- Figure 6 is a cross-sectional view showing part of the elements of the coupling device comprising, according to one embodiment, three coupling groups arranged in a flywheel, said flywheel surrounding an eccentric of ovoid shape;

- Figures 7a and 7b schematically represent a coupling group comprising working pistons arranged in their cylinder and a reserve cylinder during a transient operating phase of the device (Figure 7a) and during a phase of inactivity of the device (Figure 7b);

- Figures 8a, 8b and 9 show a device for adjusting a fluid passage section in operation during a transient phase for discharging the fluid out of the working cylinder (Figure 8a), during a transient phase d suction of the fluid in the working cylinder (FIG. 8b), and a phase of blocking the passage section between the working cylinder and the rest of the hydraulic circuit (FIG. 9), according to one embodiment, comprising a screw adjustment, a shutter rod, a shutter ring, all arranged in a flywheel and above a working cylinder;

- Figure 10 is in accordance with Figures 8a, 8b and 9, and in particular show an overpressure phase prevailing in the working cylinder during a blocking phase of the passage section in accordance with Figure 9;

- Figures 11a, 11a and 11a illustrate the locking of the working pistons by a holding device according to one embodiment;

- Figures 11b, 11b 'and 11b are figures in accordance with Figures 11a, 11a' and 11a and illustrate the holding device in an intermediate position;

- Figures 11c, 11c 'and 11c are figures in accordance with Figures 11a, 11a' and 11a and illustrate the holding device locked in an inactive position and the dog clutch engaged against the eccentric;

- Figure 12 is a table describing the state of the main elements of the coupling device during a transient phase of mechanical engagement between two half-crankshafts;

- Figure 13 is a table, similar to Figure 12, describing the state of the main elements of the coupling device during a transient phase of mechanical disengagement between two half-crankshafts.

Description of an exemplary embodiment

The embodiments which will be described below are in no way limiting; it will be possible in particular to implement variants of the invention comprising only a selection of characteristics described subsequently isolated from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention from in the prior art. This selection comprises at least one preferably functional characteristic without structural details, or with only a part of the structural details if this part only is sufficient to confer a technical advantage or to differentiate the invention from the state of the prior art.

In particular, all the variants and all the embodiments described can be combined with one another if there is nothing technically opposed to this combination.

In the figures, the elements common to several figures keep the same reference.

We will first describe with reference to Figure 1 the principle of a hydraulic coupling device according to the invention, between a first shaft 10 and a second shaft 20 coaxial therebetween. The device comprises a device forming a positive displacement pump operating in a closed circuit, actuated by the relative rotation between a first element called the first rotor and a second element called the second rotor, in which the first rotor is integral in rotation with the first shaft and the second rotor. is integral in rotation with the second shaft. For example, the first rotor is the pump body and the second rotor is the pump drive shaft. The device further comprises a device for adjusting the flow rate 50 or the fluid pressure within said closed circuit, thus carrying out a control for adjusting the flow resistance within the closed circuit, which controls the resistance to relative rotation between the first rotor and the second rotor, thereby achieving control of the torque transmitted between said first and second shafts. Preferably, the flow adjustment device is integral with the body of the pump. Preferably, the coupling device comprises an operating element 70 for actuating the flow adjustment device 50. The device according to the invention makes it possible to couple two shafts together. In addition, the device makes it possible to progressively couple the two shafts until the two shafts are integral in rotation.

According to an example of a first embodiment, as illustrated in FIG. 2, the eccentric element comprises a crank pin 111 extending along an axis parallel to the axis of rotation of the shafts and which is fixed to one end of the first shaft by a crankshaft crank 112. The device further comprises a connecting rod 321 connected to the crank pin 111 by a first end, and to a radial piston 32 of the hydraulic pump by a second end. The rod 321 thus connects the first rotor to the second rotor. When the first shaft 10 is in rotation, the arrangement of the crank pin 111 and the connecting rod 321 makes it possible to raise and lower the radial piston 32 in the flywheel 21, and thus makes it possible to circulate the hydraulic fluid on either side of the piston head via the flow control device 50.

According to an example of a second embodiment, illustrated in FIGS. 3 and following, the coupling device forming the hydraulic pump comprises a piston 32 arranged radially around the axis of rotation of the shafts 10, 20. The first rotor comprises an element eccentric 11 extending in an axial direction parallel to the axis of rotation and forms a cam opposite the radial piston 32 of the pump.

The eccentric element is fixed to one end of the first shaft 10. The second rotor comprises a flywheel 21 fixedly mounted and coaxially at one end of the second shaft, surrounding the eccentric element 11. The flywheel 21 extends in a plane perpendicular to the axis of rotation. The flywheel encloses the radial piston 32 in a cylinder 31.

Figures 3 and 4 show internal components of an internal combustion engine, the engine comprising four piston-cylinder systems distributed in a longitudinal direction. The engine comprises a first half-crankshaft 10 and a second half-crankshaft 20 arranged coaxially with the first half-crankshaft 10 along the axis of rotation 5 of the crankshafts 10, 20. The first half-crankshaft 10 comprises pins Tl, T2 and T3 and crank pins Ml and M2. The second half-crankshaft 20 includes journals T4 and T5 and crankpins M3 and M4. With reference to FIG. 4, the crank pins M1, M2, M3 and M4 are provided to be respectively surrounded by the feet of the connecting rods Bl, B2, B3 and B4 (the bearings not being shown to simplify the drawings) in a manner known by the skilled person. Similarly, the pins Tl, T2, T4 and T5 are arranged on bearings in a manner known to those skilled in the art.

According to the invention, a device for coupling the crankshafts 10, 20 is disposed between the journal T3 of the first half-crankshaft 10 and the crank pin M3 of the second half-crankshaft 20. With reference to FIGS. 3 and 4, the device for coupling has the form of a flywheel 21 arranged coaxially with the crankshafts 10, 20. The flywheel 21 has a disc 22 comprising one or more groups for coupling the crankshafts which are described below. The flywheel 21 is bored in its center to surround the pin T3. The flywheel comprises a base T3 'projecting from the axial face facing the first half-crankshaft. The base T3 'has the shape of a tube so that its internal surface and its external surface are circular cylindrical. The base T3 'makes both a bearing for the pin T3 and a pin for the pin P3.

The flywheel 21 comprises, on an axial face facing the second half-crankshaft and eccentrically radially with respect to the axis of rotation 5, a circular stud 23 projecting from the disc 22 along an axis parallel to the axis of rotation 5. The stud 23 is, in operation, arranged in a countersink 24 which is produced in the crank pin M3 of the second half-crankshaft 20. The stud 23 makes it possible to drive the coupling device in rotation when the second half-crankshaft 20 is in rotation. When the second half-crankshaft 20 is the only active crankshaft, that is to say to generate mechanical torque, the coupling device serves as a crankpin or half-crankpin M3 for the rod B3. The arrangement of the coupling device, in particular thanks to the base T3 'and to the stud 23 makes it possible to propose a space-saving device.

FIGS. 3 and 4 illustrate an embodiment for a so-called “four-cylinder” engine, but the coupling device is compatible with an engine group comprising any number of cylinders, and according to any of the known engine architectures, by example in V or online.

The coupling device comprises a radially eccentric element 11 integral in rotation with the first half-crankshaft 10. With reference to FIG. 4, the eccentric element 11 is located at the axial end of the half-crankshaft 10 facing the second half -crankshaft 20. With reference to FIGS. 3, 5 and 6, the eccentric element 11 is arranged, in operation, in the bore of the disc 22.

With reference to FIG. 5, the disc 22 of the coupling device comprises coupling groups 30. The coupling groups make it possible to synchronize the respective rotational speeds of the crankshafts. Figures 5 and 6 illustrate a particular embodiment comprising three coupling groups. Each coupling group comprises working pistons 32 respectively arranged in working cylinders 31. With reference to FIG. 5, each coupling group 30 includes a first cylinder, called working 31a and a second cylinder, called working 31b made Radially in the disc and around the axis of rotation common to the eccentric 11 and to the disc 22. The working cylinders 31a and 31b communicate with each other by a substantially sealed and closed hydraulic conduit 39 containing a hydraulic fluid (which can be considered as incompressible), for example engine oil. The hydraulic circuit is for example supplied with oil via the bearings of the crankshaft 20. In nominal operation, a leakage flow can still occur. How to fix it is described below.

The working cylinders 31a and 31b respectively contain a mobile piston 32a and 32b, which are arranged to be able to be moved apart radially (relative to the axis of rotation) by pressing against the eccentric 11 when the first half-crankshaft 10 and the second half crankshaft 20 have a relative rotational movement with respect to each other. Each working piston 32a and 32b makes it possible to vary the volume of fluid contained in the cylinders 31a and 31b and to circulate the hydraulic fluid in the hydraulic conduit 39 during the movements of said pistons relative to the eccentric 11, thus forming a circuit sealed hydraulic closed.

Cooperation of working pistons with eccentric

According to the invention and with reference to Figures 5 and 6, the eccentric has a cylindrical profile with variable radius. Referring to Figure 5, the eccentric 11 has a triangle-shaped profile, that is to say having three vertices. Referring to Figure 6, the eccentric 11 has an ovoid profile with two opposite vertices.

When it is necessary to couple the two half-crankshafts, the working pistons 32, which are arranged in the flywheel 21 rotating clockwise by the half-crankshaft 20, comes into contact with the eccentric 11 rotating at a very low or even zero speed of rotation. Each working piston will then go up and down as a function of the radius of the eccentric seen by said piston during the rotation of the rotary flywheel relative to the eccentric. Thus, at least a first part of the profile is a radially increasing profile, said rising profile, and at least a second part of the profile is a radially decreasing profile, said descending profile, which are arranged successively and alternately on the periphery of the eccentric . With reference to FIG. 5, the eccentric 11 having a triangle-shaped profile comprises three rising profiles 11c and three descending profiles 11d delimited by marks drawn on the circumference of the eccentric. Referring to Figure 6, the eccentric 11 having an ovoid profile includes two rising profiles 11c and two descending profiles lld.

The angular distance of the working rolls is chosen according to the profile of the eccentric, that is to say the number of vertices, so that, for the same coupling group, the first piston is rising while the second piston is descending and thus realize the circulation of the fluid.

FIG. 7a schematically represents the operation of a coupling group 30 in cooperation with an eccentric rotating in a counterclockwise direction. The working pistons are shown in parallel and the upward 11c and downward lld profiles are represented by oblique segments to simplify the drawing. The working pistons 32a and 32b are arranged so that:

when the increasing profile 11c pushes the pistons 32a of the coupling group in an upward movement, then constituting an upward piston, said upward movement pushes the other piston 32b of said group towards the eccentric in a downward movement via the hydraulic fluid , thus constituting a descending piston; and said decreasing profile lld authorizes the downward movement of said downward piston.

Preferably, each working cylinder 31 contains an elastic return spring for pushing the associated working piston 32 towards the eccentric 11.

Reserve cylinder

With reference to FIGS. 5, 6, 7a and 7b, the disc 22 further comprises, for each coupling group, a so-called reserve cylinder 35 which comprises an elastic enclosure communicating with the hydraulic conduit 39 of said group 30, so as to be able to , automatically maintain sufficient pressure in said hydraulic circuit. Preferably, each reserve cylinder 35 of the same group 30 contains hydraulic fluid in order to compensate for any losses such as leaks of hydraulic fluid.

Each reserve cylinder 35 is closed at one end and open to the hydraulic conduit 39. The reserve cylinder 35 contains a movable piston resting elastically on said closed end. According to a preferred embodiment and with reference to Figures 6, 7a and 7b, the movable piston of the reserve cylinder is produced by a plate 36 provided with a sealing segment. The plate 36 bears against the closed end by means of an elastic return spring 37. The plate is designed to translate along the axis of the reserve cylinder. In the event of a leak in the hydraulic circuit, the reserve of fluid contained in the reserve cylinder decreases so that the plate 36 translates radially towards the outside of the disc 22.

In a particular operating mode and with reference to FIG. 7b, the reserve cylinders 35 make it possible to admit the hydraulic fluid coming simultaneously from the first cylinder 31a and from the second cylinder 31b of the same coupling group 30 into the reserve cylinder 35, thus authorizing a simultaneous ascent of said first and second pistons 32a and 32b. Simultaneously, the plate 36 compresses the spring 37 due to the admission of fluid from the cylinders 31a and 31b. Raising the working pistons prevents them from hitting the eccentric unnecessarily when a single half-crankshaft is used.

With reference to FIGS. 4, 7a, 7b, the working pistons 32a and 32b comprise a groove 34. Each groove is designed to cooperate by mechanical engagement with a retaining finger for retaining said piston in the high position so that the ends of the pistons of work facing the eccentric can no longer touch the eccentric. The retaining finger, which is further described below, can be moved from the groove so that it leaves the associated working piston free in translation in its cylinder.

Adjustment device

According to the invention, the coupling device comprises at least one device for adjusting a passage section of said hydraulic circuit between the first cylinder and the second cylinder. Referring to Figure 7a, an adjustment device 50 is provided for each working cylinder 31a, 31b. The adjustment device is controlled to selectively open said passage section, allowing the passage of the fluid from the first cylinder 31a to the second cylinder 31b and vice versa, a partial or total closure of said passage section, forming a so-called braking section. which brakes or blocks said passage of the fluid, and consequently the displacement of the rising piston, which then opposes the rotation of the increasing profile 11c, thus producing braking or blocking the rotation of the eccentric relative to the steering wheel.

With reference to FIGS. 8a, 8b, 9 and 10, the device 50 for adjusting a passage section between a cylinder and a duct comprises, for each working cylinder 32a, 32b, a closure ring 51 provided to cooperate with a movable closure rod 52.

The closure ring 51 has the shape of a ring inserted in the working cylinder. The closure ring 51 has an inner surface having a frustoconical profile whose diameter decreases in the radial direction, away from the axis of rotation. The inner surface of the ring forms a communication opening 513 between the cylinder 31a, 31b and the rest of the hydraulic circuit of the coupling group.

The movable closure rod 52 comprises a contact surface 53 which forms a bearing capable of coming into complete sealed contact with said communication opening, and which cooperates with the opening of the closure ring to open or close said opening 513 and thus determine the braking section. The value of the braking section is determined by the position of the contact surface 53 of the closure rod relative to the communication opening 513. The contact surface 53 of the closure rod 52 is provided to take bearing against the frustoconical profile of the closure ring 51. According to the preferred embodiment, the contact surface 53 is spherical. The diameter of the sphere is chosen to be greater than the minimum diameter of the frustoconical profile of the closure ring.

The adjustment device 50 comprises an adjustment screw 56 arranged to act on the position of the shutter rod 52 and thus act on the section for passage of the fluid. The adjustment screw 56 is screwed radially into the disc 22. The closure rod 52 is mounted coaxially with the adjustment screw 56 by means of a non-opening bore produced in said screw.

According to the embodiment shown, the adjusting screw 56 carries the closure rod 52 by a movable link in translation under the effect of the circulation of the fluid. The closure rod 52 bears against the adjustment screw 56. In addition, a cage 59 is provided fixed to the closure ring 51, the cage 59 comprising openings 60 to allow the fluid to pass.

The cage 59 makes it possible to retain the shutter rod 52 in the event that it is not retained in translation. According to another embodiment, the shutter rod is fixed to the adjustment screw.

The adjusting screw 56 is controlled in rotation to move the closure rod 52 in translation relative to the opening of said closure ring 51, and thus adjust said passage section.

With reference to FIGS. 8a, 8b, 9 and 10, the operation of the device for adjusting the passage section for each working cylinder is described. With reference to FIGS. 8a and 8b, the start of the transient phase of the coupling of the crankshafts is described. FIG. 8a illustrates a position of the closure rod 52 in abutment against the bore of the adjustment screw 56, determined by the position of the adjustment screw, in which the position of the closure rod 52 vis-à-vis screw of the sealing ring 51 determines a first section for passage of the fluid, called braking.

FIG. 8b illustrates a disengaged position of the screw 56 in which the position of the shutter rod 52 with respect to the shutter ring 51 determines a second section of passage of the fluid, called the inlet, which is larger than the first passage section because further away from the frustoconical wall.

The adjustment device makes it possible to produce a valve with two positions which authorizes, for the same adjustment of the adjustment screw: o in the direction of the cylinder outlet, an outlet flow rate regulated by the position of the adjustment screw, and o in the direction of entry into the cylinder, an intake flow greater than the outlet flow.

By controlling the adjusting screw 56 in rotation in order to move it so as to deviate radially from the axis of rotation, the closure rod 52 also translates so as to deviate radially from the axis of rotation so that the contact surface 53 approaches the frustoconical wall of the communication opening 513 of the closure ring 51, and thus reduce the passage section. With reference to FIG. 9, the adjusting screw 56 is sufficiently raised so that a clearance appears between the end of the closure rod and the bottom of the bore 57. The contact surface 53 is then in contact with the frustoconical wall of the closure ring 51 so as to close the passage section. The circle 54 highlights the area of the shutter rod in contact with the shutter ring 51.

According to a particular embodiment and with reference to FIG. 10, the closure ring 51 is fitted free in one end of the working cylinder, and is held there by an elastic return element 62, for example a leaf spring crossed by the rod, of a determined stiffness to allow, beyond a determined pressure in the cylinder, a displacement of said ring towards the outside of the cylinder so as to release an additional leakage section around said ring. The shutter rod 52 being stopped in translation by the adjusting screw 56, the lifting of the shutter ring 51 causes the frustoconical wall to move away from the contact surface 53, and thus reopens the section passage between the shutter rod 52 and the shutter ring 51. In addition, the fluid can also escape along the outer surface of the shutter ring.

In order to control the axial translation of the adjusting screw, the coupling device comprises at least one operating element which surrounds the steering wheel and is arranged to translate in a direction parallel to the axis of the steering wheel. Preferably, the operating element has at least one shape cooperating with at least one crank pin 58 (FIGS. 8a, 8b, 9 and 10) projecting from said adjusting screw and extending in the radial direction, for screwing or unscrewing said adjusting screw according to said translation.

With reference to FIGS. 3 and 4, the operating element comprises a crown 70. The crown has on its outer circumference: o on the one hand at least a portion of straight toothing which cooperates with a pinion (or for example a screw without end) to modify the angular position of the crown, and o on the other hand at least a portion of helical thread which cooperates with the engine block to transform said rotation into axial translation, thus performing the operation of the adjustment screws.

According to a particular embodiment, the crown has, on its inner circumference, for example a shape of a "U" groove extending radially towards the axis of rotation. One of the sides of the groove can be completed or replaced by axial elastic return means which replace one of the walls of the groove, for example a spring strip. The groove is intended to receive the crank pins of the adjusting screws. When the flywheel rotates, the crankpins 58 rotate at the same angular speed as the flywheel. The crankpins slide in the groove of the crown in a circular path. During the axial translation of the crown, a first side of the groove pushes the pins. Due to the thread, the action on the crank pins causes the adjustment screws to rotate. The movement of the crown allows the screwing or unscrewing of the adjustment screws to be controlled. To control the adjusting screws in the opposite direction, the crown is controlled in translation in the opposite direction so that the second side of the groove bears against the crank pins.

Dog clutch device

According to the invention, the coupling device further comprises a dog clutch device 80 arranged to achieve coupling by mechanical engagement of the two half-crankshafts. Referring to Figure 4, the dog clutch device is arranged coaxially with the flywheel 21 and faces the half-crankshaft 20. The dog clutch device 80 comprises three arms 82 arranged radially and angularly distributed equidistantly. Each arm 82 has a curved end 84 designed to fit into an axial groove formed on the outer circumference of the steering wheel 21.

Referring to Figures 11a, 11b and 11c the dog clutch device comprises at its center teeth 81 arranged to cooperate with teeth 14 carried by the axial face of the eccentric 11 of the half-crankshaft 10. When the dog clutch device is coupled by engagement on the eccentric, the support of the curved ends in the respective axial grooves makes it possible to transmit the mechanical torque between the two half-crankshafts. This arrangement also makes it possible to drive the two half-crankshafts 10, 20 in rotation without necessarily needing coupling groups. The interconnection device has the advantage of being compact and ensuring the transmission of torque between the two half-crankshafts.

Actuation of the dog clutch device

The dog clutch device is integral in rotation relative to the flywheel 21. The dog clutch device is designed to translate along the axis of rotation 5, by sliding the curved ends 84 of the arms 82 in the respective axial grooves. The dog clutch device further comprises a cylindrical base, projecting in the direction of the steering wheel and coaxial with the steering wheel, which is designed to slide in a cylindrical bore arranged in the steering wheel. The base makes it possible to guide the translation of the dog clutch device relative to the steering wheel.

Preferably each arm 82 carries a control lug 83 which extends in a radial direction and projects from the curved end 84 of the arm 82. According to the invention, the control lugs 83 cooperate with an operating element movable in translation to control the dog clutch under the effect of the translation of said operating element. According to the preferred embodiment, the element for operating the dog clutch is the same as the element for operating the adjusting screws. With reference to FIGS. 11a, 11a ', 11b, 11b', 11c and 11c ', the element for operating the dog clutch is the crown 70. In this embodiment, the crown 70 acts both on the crank pins of the screws. adjustment and on the control pins 83. In the figures, the control pins 83 have the shape of a cylindrical rod. According to other embodiments, the pins can be of polygonal shape, for example rectangular.

The crown 70 is provided to press against the control pins 83 during its translation to clutch, or to close the passage sections of the hydraulic circuits, therefore connecting the two half-crankshafts 10, 20. In the opposite direction, that is to say -display declutching (passage from a four-cylinder engine to a two-cylinder engine) the clutch device 80 returns to the initial position by an elastic return element.

Holding finger

According to a particular embodiment, each arm 82 of the dog clutch device is connected to a holding finger 75 by means of a lever 72 in order to control the movement of said finger 75 out of the groove 34. Preferably and in with reference to FIGS. 11a, 11b and 11c each retaining finger 75 is pivotally connected with respect to the flywheel along a pivot axis 73 extending in a direction substantially perpendicular to the axis of rotation of the crankshafts. Preferably, the lever 72 and retaining finger 75 assembly at the end of the lever is disposed along an axial face of the flywheel facing the half-crankshaft 20, the lever 72 being disposed at all times between an arm of the device clutch and the steering wheel. Preferably, each arm 82 bears at a point 74 against a face of the lever 72 at a non-zero distance from the pivot axis 73 and opposite the retaining finger relative to the pivot axis 73 so as to cause the pivoting of the lever 72 and thus the withdrawal of the retaining finger 75 from the groove 34.

According to an even more particular embodiment and with reference to FIGS. 11a, 11a, 11b, 11b ', 11c and 11c', each holding lever 72 is extended in the direction of, and up to the crown 70, so that this extension forms an actuating finger 71. Preferably, the actuating finger 71 extends along an axial face of the flywheel 21 facing the second half-crankshaft 20. The actuating finger 71 is provided for be actuated by the crown 70 during declutching (passage from a so-called “four-cylinder” engine to a so-called “two-cylinder” engine). For example, an outer edge of the crown presses on each actuating finger 71 to rotate the lever 72 in a direction of rotation opposite to the previous direction to insert the holding fingers 75 into the respective grooves 34.

Steps to synchronize the withdrawal of the retaining fingers and the dog clutch

With reference to Figures 11a, 11a, 11a, 11b, 11b ', 11b, 11c, 11c' and 11c, the disengagement of the retaining fingers 75 from the respective grooves 34 of the working pistons 32a, 32b is described below. and the coupling by mechanical engagement of the dog clutch device 80 on the eccentric 11. Subsequently and to simplify the description, there is described a single holding lever comprising a holding finger and an actuating finger.

As seen above and with reference to Figures 11a, 11a and 11a, when a single half-crankshaft is active, the retaining finger 75 is inserted into the groove 34 of the associated working piston 32 to hold it in the high position. The crown 70 is applied against the actuating finger 71 of the lever 72 to force the retaining finger 75 to remain in the groove 34 by the effect of the lever arm. The lever 72 extends in a substantially inclined direction, that is to say a direction forming a non-zero angle relative to the vertical. The dog clutch 80 is then pushed back towards the half-crankshaft 20 so that the teeth 81 of the dog clutch 80 are then distant from the teeth of the eccentric 11 (FIG. 11a).

Referring to Figures 11b, 11b 'and 11b, the crown 70 is actuated so that it translates axially along the outer circumference of the steering wheel 21 to actuate the adjustment screws. Simultaneously, the crown 70 releases the support on the actuating finger 71 which causes a slight pivoting in the direction of unlocking of the retaining finger 75 out of the groove. The lever 72 extends in a substantially vertical direction and allows the retaining finger to come out of the associated groove, and thus allows the working piston to be able to translate in the working cylinder. In this intermediate position, the dog clutch device is not actuated in translation.

Referring to Figures 11c, 11c 'and 11c, the dog clutch 80 is engaged on the eccentric. The crown 70 has been translated to close the passage sections of the hydraulic circuits so that the working pistons block the rotation of the eccentric relative to the flywheel

21. The crown 70 is pressed against the control pins 83 so that the teeth 81 of the dog clutch device are coupled with the teeth 14 of the eccentric 11 (FIG. 11c). Simultaneously, each arm 82 of the clutch dog clutch device, by means of point 74, presses on one face of the holding lever 72 to pivot said lever in the direction of withdrawal of the holding fingers out of the associated groove.

Mating process

FIG. 12 is a table summarizing the coupling by mechanical engagement, and in particular the transient operating phase, of the two half-crankshafts (passage from a so-called “two-cylinder” engine to a so-called “four-cylinder” engine).

At low stresses, the engine is designed to operate with two piston-cylinders (i.e. half of the engine displacement) by means of a single half-crankshaft, in this case the half-crankshaft 20 with reference to FIGS. 3 and 4. The half-crankshaft 20 is in rotation about the axis 5 by means of the pins T5, T4 and T3 '. The trunnion T3 'has the particularity of turning inside a bearing like the other trunnions and also around the trunnion T3 of the half-crankshaft 10. The half-crankshaft 10 is this inactive moment and has a zero or at least rotation speed much lower than that of the half-crankshaft 20.

The half-crankshaft 20 rotates the flywheel 21 by means of the stud mounted for rotation in the crank pin M3 of the half-crankshaft 20. The flywheel is also in rotation relative to the crown, which is fixed relative to the frame. The crown keeps the working pistons in the high position by means of the respective holding fingers, themselves held by the action of the crown on the holding lever. The crown also maintains the adjustment screws in the low position so that the passage of the fluid is possible. The dog clutch device is in its rest position, that is to say disengaged from the eccentric.

When the user places greater demands on the engine, that is to say during acceleration, the engine control controls the mechanical engagement of the half-crankshafts. At time T0, the crown moves slightly to unlock the working pistons. Then, at time Tl, the synchronization of the rotational speeds of the half-crankshafts begins. For each coupling group, the working pistons are then pushed towards the eccentric of the first half-crankshaft both by the associated coupling springs and by the hydraulic fluid which was, the previous moment, kept under pressure in a cylinder reserve. The working pistons, at instant Tl are all descending so that they strike the eccentric. The sealing rods translate downwards and bear on the retaining cages to allow the admission of the fluid into the working cylinders (FIG. 8b).

Then immediately afterwards, because the flywheel is rotating relative to the eccentric, each end of a working piston is in contact successively with a rising and falling profile (FIG. 7a). When the end of a working piston follows a rising profile of the eccentric, said piston is pushed back into its working cylinder compressing the coupling spring and expelling the fluid contained in the working cylinder towards the hydraulic conduit by the through the opening between the shutter ring and the shutter rod pushed back into the bore of the adjusting screw. The fluid is returned to the hydraulic conduit connecting the two working cylinders and to the working cylinder housing the descending working piston. This transfer of fluid between the working cylinders continues with each passage of a rising and falling profile of the eccentric.

During the transient phase of coupling and in a fairly short time interval, the crown moves axially and actuates all the adjustment screws in the direction of unscrewing, that is to say to bring each screw up so that the contact surface of the closure rod approaches the frustoconical wall of the closure ring, reducing the opening for passage of the fluid during the expulsion of the fluid from the working cylinder. Thus, the fluid has, as and when the adjustment screw rises, a decreasing section reducing the amount of fluid that can leave the cylinder when the piston is rising, thus forming a non-return effect. On the other hand, during admission, the fluid can re-enter the cylinder as easily as at time Tl since the shutter rod is mounted free in translation in the bore of the adjusting screw. The working pistons are increasingly resistant to each rise, that is to say to each passage of a rising profile of the eccentric.

Each time an end of a piston passes over a rising profile, the force exerted by the piston on a rising profile of the eccentric increases because it rises in its working cylinder less quickly. In this way, the working pistons rotate the eccentric and then reduce the difference in speed between the half-crankshafts to allow coupling. At time Tn, when the half-crankshafts are almost at the same speed of rotation, the adjustment screws go up and are almost in the high position or are in the high position so that each section of the fluid passage is minimal or even zero. The working pistons which are rising pistons compress the fluid so that the contact surface of the closure rod rests on the closure ring closing the passage section. The working pistons which are descending pistons suck one last time of the fluid before being stopped because the rising pistons have canceled the difference in speed of rotation between the eccentric and the flywheel and that the fluid contained in said cylinder is prisoner due to the start of the piston rise and therefore the closure of the passage section as for the rising pistons. At time Tf, all the working pistons are blocked on the profile of the eccentric, the contact surfaces of the closure rods are pressed against the closure rings. The dog clutch device is engaged. The engine can then operate with the two half-crankshafts connected.

If during the transient phase, the fluid is in overpressure in a working cylinder, the closure ring inserted in said cylinder is raised to release an additional leakage section. The fluid can then escape between the shutter rod and the shutter ring, and also between the outer surface of the shutter ring and the working cylinder.

According to a particular embodiment, a coding device is provided between the two half-crankshafts.

Uncoupling process

FIG. 13 is a table summarizing the uncoupling of the two half-crankshafts (passage from a so-called “four cylinder” engine to a so-called “two cylinder” engine).

When the engine operates with the two half-crankshafts, the clutch mechanism is engaged, the adjusting screws are reassembled so that the fluid cannot circulate in the hydraulic circuit and the working pistons are stationary, pressed against the profile of the eccentric.

When the user uses the engine little or less, the engine control controls the mechanical disengagement of the half-crankshafts. At time TO, the crown slightly translates to release the dog clutch which returns to the initial position, that is to say clutch, by elastic return means. Then at time Tl, the adjustment screws descend (that is to say are screwed into the flywheel) so that the closure rods descend against the retaining cages also to allow the fluid to circulate in the hydraulic circuits of each coupling group. The working pistons go up and down as described above. The adjustment screws descend until they are in the low position at time Tn.

At the end of uncoupling, the crown presses against the holding levers by means of the actuating fingers to insert the respective holding fingers in the grooves of the working pistons.

The uncoupling of the first half-crankshaft makes it possible to limit 10 or even eliminate the friction of the pistons of the disengaged half-crankshaft and thus makes it possible to limit both the fuel consumption and the emission of polluting gases when the engine is lightly requested by the driver .

Of course, the invention is not limited to the examples which have just been described and numerous modifications can be made to these examples without departing from the scope of the invention.

Claims (16)

Claims 1. Hydraulic coupling device between a first shaft (10) and a second shaft (20) coaxial with each other, characterized in that it comprises a device forming a positive displacement pump operating in closed circuit, actuated by the relative rotation between a first element called first rotor (11) and a second element called second rotor (21), in which the first rotor (11) is integral in rotation with the first shaft (10) and the second rotor (21) is integral in rotation with the second tree (20); and in that it further comprises a device for adjusting the flow rate or the fluid pressure within said closed circuit, thus carrying out a control for adjusting the flow resistance within the closed circuit, which controls the resistance to relative rotation between the first rotor (11) and the second rotor (21), thus achieving control of the torque transmitted between said first (10) and second (20) shafts. 2. Coupling device in rotation between a first half-crankshaft (10) and a second half-crankshaft (20) coaxial with each other, characterized in that it comprises: a radially eccentric element (11) integral in rotation with the first half-crankshaft (10), - a flywheel (21) integral in rotation with the second half-crankshaft (20) and arranged coaxially around the eccentric element (11), said flywheel comprising one or more coupling groups (30) each including at least a first cylinder ( 31a), known as working and a second cylinder (31b), said to be radial working, which communicate with each other by a sealed hydraulic circuit containing a hydraulic fluid, said cylinders (31a, 31b) each containing a movable piston (32a, 32b), which is arranged to be able to be moved apart radially by pressing against the eccentric (11) when the first half-crankshaft (10) and the second half-crankshaft (20) have a relative rotational movement relative to each other ; in that the eccentric (11) has at least one radially increasing profile (11c), said rising profile, and at least one radially decreasing profile (lld), said descending, which are arranged and arranged so that: - when the increasing profile (11c) pushes one of the pistons (32a, 32b) of said group (30) in an upward movement, then constituting a rising piston, said upward movement pushes the other piston of said group towards the eccentric a downward movement via said hydraulic fluid, then constituting a downward piston; and - said decreasing profile (lld) authorizes the downward movement of said descending piston; and in that said flywheel (21) further comprises at least one adjustment device (50) of a passage section of said hydraulic circuit between said first and second cylinders, which is controlled to selectively perform: an opening of said passage section, authorizing the passage of the fluid from the first cylinder (31a) to the second cylinder (31b) and vice versa, a partial or total closure of said passage section, forming a so-called braking section which brakes or blocks said passage of the fluid, and consequently the displacement of the rising piston, which then opposes the rotation of the increasing profile, thereby producing braking or blocking the rotation of the eccentric relative to the flywheel (21). 3. Coupling device according to claim 2, characterized in that the flywheel carries, for each working piston, a retaining finger (72) which can be moved between: a holding position in which it cooperates by mechanical engagement with an accident in the shape of the piston (34) to retain said piston in the high position, and - A clear position in which it leaves said piston free in translation in its cylinder. 4. Coupling device according to claim 2 or 3, characterized in that the flywheel (21) further comprises, for one or more coupling groups (30), one or more so-called reserve cylinders (35) which include a elastic enclosure communicating with the hydraulic circuit of said group (30), so as to be able, automatically or selectively: - maintain sufficient pressure in said hydraulic circuit, - admitting hydraulic fluid coming simultaneously from a first and from a second cylinder of the same group, thus authorizing a simultaneous ascent of said first and second pistons (32a, 32b). 5. Coupling device according to claim 4, characterized in that at least one reserve cylinder (35) is closed at one end and contains a movable piston (36) resting elastically on said closed end. 6. Coupling device according to claim 4 or 5, characterized in that each coupling group (30) comprises exactly one reserve cylinder (35) and two working cylinders (31a, 31b). 7. Coupling device according to any one of claims 2 to 6, characterized in that the adjustment device (50) comprises, for one or more working rolls: o a closure ring (51) fixed to the steering wheel and which includes a communication opening (513) between the cylinder (31a, 31b) and the hydraulic circuit of the coupling group (30), o a movable closure rod ( 52) comprising a contact surface (53) cooperating with the opening of the closure ring for, depending on its position, more or less opening or closing said opening and thus determining the braking section, o an adjusting screw (56 ) mounted in the steering wheel, on which the shutter rod bears or is fixed, and in that the adjusting screw is controlled in rotation to move the shutter rod in translation relative to the opening of said ring d 'shutter, and thus adjust said passage section. 8. Coupling device according to claim 7, characterized in that the adjusting screw (56) carries the closure rod (52) by a movable link in translation under the effect of the circulation of the fluid, between: a position in abutment against the screw, determined by the position of the adjusting screw, in which the position of the shutter rod vis-à-vis the shutter ring determines a first section for passage of the fluid, called braking, o a position released from the screw in which the position of the closure rod vis-à-vis the closure ring determines a second fluid passage section, called the intake section, larger than the first passage section, thus producing a two-position valve which allows, for the same adjustment of the adjusting screw: o in the direction of the cylinder outlet, an outlet flow adjusted by the position of the adjusting screw, and o in the direction of the entry into the cylinder, an inlet flow greater than the outlet flow. 9. Coupling device according to claim 7 or 8, characterized in that: o the opening of the closure ring has a shape which widens towards the working piston, o the adjusting screw (56) is outside the cylinder, and o the closure rod (52) passes through said opening and has an enlarged end on the side of the piston carrying the contact surface which cooperates with the flared shape of the opening of the closure ring. 10. Coupling device according to any one of claims 7 to 9, characterized in that the closure ring (51) is freely mounted in one end of the working cylinder, and is held there by an elastic return element (62) of a determined stiffness to allow, beyond a determined pressure in the cylinder, a displacement of said ring (51) towards the outside of the cylinder so as to release an additional leakage section. 11. Coupling device according to any one of claims 7 to 10, characterized in that the adjusting screw (56) is arranged radially on the periphery of the flywheel, in that it comprises at least one operating element ( 70) stationary in rotation which surrounds the flywheel (21) and is arranged to translate in a direction parallel to the axis of the flywheel, which operating element has at least one shape cooperating with at least one pin (58) projecting from said adjusting screw (56), for screwing or unscrewing said adjusting screw (56) along said translation. 12. Coupling device according to any one of claims 1 to 11, characterized in that it further comprises a dog clutch device (80) arranged to effect a coupling by mechanical engagement of the two half-crankshafts (10, 20 ). 13. Coupling device according to the preceding claim, characterized in that the dog clutch device (80) comprises: - on the one hand, one or more latches (81) movable in translation and fixed in rotation relative to the steering wheel, which are arranged to cooperate with accidents of complementary shape (14) carried by an axial face of the eccentric, and - on the other hand one or more control pins (83) which cooperate with an operating element (70) movable in translation to control the dog clutch or the dog clutch under the effect of the translation of said maneuver element. 14. Coupling device according to claim 12 or 13, 5 characterized in that the dog clutch device (80) comprises one or more arms which carry the control pins (83) and control the holding fingers (72) of the pistons working (32a, 32b). 10 15.Engine comprising at least a first and a second half-crankshaft coupled by a coupling device according to any one of claims 1 to 14. 16. Vehicle comprising an engine according to the preceding claim. 1/8