FR3080575A1 - <P> ENGAGEMENT ASSEMBLY FOR A HYDRAULIC TRANSMISSION SYSTEM OF A VEHICLE </ P &gt; - Google Patents

Abstract

The invention relates to an engagement assembly (1) for a hydraulic transmission system (2), said system (2) comprising: - a hydraulic machine (201), and - a hydraulic circuit (21) comprising a high pressure line (211), the engagement assembly (1) comprising: - a clutch device (3) configured to provide coupling between the hydraulic machine (201) on the one hand, and a driving element (4) or an element to be driven on the other hand, - a first hydraulic clutch control (31) configured to be connected to a booster pump (23), the engagement assembly (1) being characterized in that comprises: - a second hydraulic clutch control (32) configured to be connected to the high pressure line (211).

Description

TECHNICAL AREA

The invention relates to the engagement of a hydraulic transmission of a vehicle.

The invention relates more specifically to an engagement assembly for a hydraulic transmission system of a vehicle, and to an engagement method by means of such an assembly.

STATE OF THE ART

There is shown in Figure 1 a known engagement assembly 1 for hydraulic transmission system 2 of a vehicle. Such an engagement assembly 1 has in particular been described in application EP 2 666 657 in the name of the Applicant.

The hydraulic transmission system 2 includes:

a hydraulic machine 20,

a hydraulic consumer 200 connected to the hydraulic machine 20, and a charging or booster circuit 22, said charging circuit 22 being connected to the inlet or outlet of the hydraulic machine 20 via a hydraulic circuit 21, and a booster pump 23 configured to charge the hydraulic circuit 21 from a hydraulic tank 24 at atmospheric pressure.

Engagement set 1 includes:

a clutch device 3, or coupler, configured to couple between the hydraulic machine 20 on the one hand, and a drive element on the other hand 4, and a hydraulic control 30 configured to be connected to the pump force-feeding 23, so as to actuate the clutch device 3.

The hydraulic control 30 comprises a support cylinder (not shown), as well as a chamber (not shown) fluidly connected to the booster pump 23, so that the pressure within the chamber corresponds to the pressure supplied by the booster pump 23.

The clutch device 3 comprises, for its part, a set of first friction discs (not shown), connected to a shaft of a hydraulic machine 20, and a set of second friction discs (not shown), connected to a shaft. drive element 4.

The actuator of the hydraulic control 30 is movable between a first position, where it does not request the engagement of all of the first friction discs with the set of second friction discs, and a second position where the setting grip is assured. The passage from the first position to the second position is then ensured by the pressure within the chamber (i.e. the pressure supplied by the booster pump 23) which controls the positioning of the jack. By "pilot", we understand "activate", "command" or "implement". In addition, the movement of the jack goes against a clutch return spring (not shown) configured to ensure that the jack is in its first position, and therefore that the clutch device 3 is not engaged, when the pressure within the chamber is not established.

Thus, when the hydraulic control 30 is controlled to engage the hydraulic transmission system 2, the chamber is supplied by the booster pressure of the booster pump 23, which ensures the coupling of the hydraulic machine 20 and the element d drive 4, via the first and second friction discs of the clutch device 3. In addition, the contact pressure of the discs is ensured by the booster pressure supplied by the booster pump 23.

The disengagement of the clutch device 3 is implemented by the connection 33 of the chamber of the hydraulic control 30 with the reservoir 24, coupled to the opposing action of the return spring.

The booster pump 23 also fills and rinses the hydraulic circuit 21 at low pressure, from the reservoir 24, but can also be used in the control of other hydraulic members such as the hydraulic machine 20. By "rinsing" of the hydraulic circuit means a "sweep" function of the hydraulic circuit, for example for cooling and / or lubrication ("flushing" in English).

Such an engagement assembly 1 has many drawbacks.

First of all, in order to obtain a fairly high clamping pressure from a relatively low booster pressure, it is necessary that the chamber has a large thrust surface, and therefore that the jack displaces a large volume of hydraulic fluid. Then, so that the clutch device 3 can be able to transmit all the torque supplied by the drive element 4 while being only controlled by the pressure of the booster pump 23, it is necessary to provide it with a large quantity of disks and / or disks of large dimensions. This results in a significant bulk, either in length or in diameter, and further reduces the adaptability of such an engagement assembly 1 on any type of vehicle. Furthermore, the engagement and disengagement of the clutch device 3 are not sufficiently reactive because the quantity of hydraulic fluid to be displaced in order to set the support jack in motion is high, which requires either a time of implementation. very long cylinder, therefore a system that is not very reactive, ie a large booster pump, in that it must provide a large flow rate. Having an oversized booster pump is cumbersome and leads to significant energy expenditure at all times.

There is therefore a need for a set of engagement for a hydraulic transmission system of a vehicle which makes it possible to remedy at least one of the aforementioned drawbacks.

SUMMARY OF THE INVENTION

An object of the invention is to recover the movement of a drive element, such as a drive shaft, in order to actuate a hydraulic machine, such as a power pump.

Another object of the invention is to be able to couple and / or decouple a hydraulic machine, such as a power pump, from a drive element, such as a drive shaft, and this dynamically, c is fast enough.

Another aim is to obtain a powerful but rapid clutch device, controlled by a pressure supplied by a small booster pump.

Another object of the invention is to be able to transmit torques of high intensity by means of a clutch device whose size is reduced.

Another object of the invention is to limit the vacuum drag torque of the booster pump.

Another object of the invention is to be able to disengage the drive source as close as possible to the drive element.

The invention proposes in particular an engagement assembly for a hydraulic transmission system, said system comprising:

- a hydraulic machine, and

- a hydraulic circuit comprising a high pressure line, the engagement assembly comprising:

- a clutch device configured to ensure coupling between the hydraulic machine on the one hand, and a drive element or an element to be driven on the other hand,

- a first hydraulic clutch control configured to be connected to a booster pump, the engagement assembly being characterized in that it comprises a second hydraulic clutch control configured to be connected to the high pressure line.

Thanks to such an assembly, it is possible to transmit torques of high intensity between a hydraulic machine on the one hand, and a drive element or an element to be driven on the other hand, without oversizing the clutch device, by including the hydraulic control components and the booster pump. Indeed, the first hydraulic control ensures, at first, the start of the engagement. However, the booster pressure is not sufficient to transmit all the torque supplied by the hydraulic machine or the drive element. Consequently, once a first pressure has been established in the high pressure line, the second hydraulic control ensures the transmission of all of the torque supplied, by establishing a second pressure, greater than the first pressure. It is thus possible to transmit the whole of a torque through a clutch device, and this from a booster pump operating at moderate pressure. The size of the clutch device is also reduced, as is the volume of the booster pump, since it is no longer necessary to transmit the entire torque to the booster pressure.

The assembly according to the invention may also include the following characteristics taken alone or in combination:

- it is also characterized in that:

o the first hydraulic control is configured to ensure partial engagement of the clutch device, so that part of the torque supplied by the hydraulic machine or by the drive element, is transmitted via the device clutch, and o the second hydraulic control is configured to ensure full engagement of the clutch device, so that all of the torque supplied by the hydraulic machine, or by the drive element, is transmitted via the clutch device,

- it is also characterized in that:

o the first hydraulic clutch control comprises a first chamber, and o the second hydraulic clutch control comprises a second chamber, the first chamber being independent of the second chamber,

- it further comprises a piloted directional valve, configured to connect the first hydraulic control alternately to the booster pump outlet or to an atmospheric pressure tank,

- The hydraulic circuit is closed circuit and includes a first line and a second line, the assembly further comprising a high pressure selector, configured to provide the fluid connection between the second hydraulic control and that of the first or second line which is the high pressure line,

- the hydraulic machine is a power pump connected to a drive element,

- the drive element is an axle of the vehicle,

- the drive element is a vehicle drive shaft,

- the drive element is a PTO of the vehicle,

- the hydraulic machine is a hydraulic motor connected to an element to be driven,

- the element to be driven is an axle of the vehicle, and

- the engagement assembly is further configured to be integrated into the hydraulic machine.

The invention further relates to a vehicle comprising an assembly as previously described.

Finally, the invention relates to a method of engaging a hydraulic transmission system of a vehicle, said system comprising:

- a hydraulic machine, and

- a hydraulic circuit comprising a high pressure line, the method being implemented by means of an engagement assembly as previously described, the method comprising the steps of:

- supply of the first hydraulic clutch control of the clutch device by means of the booster pump so as to ensure partial engagement of the clutch device, and

- supply of the second hydraulic control of the clutch device by means of the high pressure line so as to ensure complete engagement of the hydraulic device.

QUICK DESCRIPTION OF THE FIGURES

Other characteristics, objects and advantages of the present invention will appear on reading the detailed description which follows and with reference to the appended drawings given by way of non-limiting example and in which:

FIG. 1, already described, illustrates an engagement assembly for a hydraulic system of a vehicle, for example a transmission, which is known from the state of the art,

FIG. 2 illustrates a first exemplary embodiment of an engagement assembly according to the invention,

FIG. 3 illustrates a second embodiment of an engagement assembly according to the invention, and

- Figure 4 is a flowchart illustrating an example of implementation of an engagement method according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the figures, we will now describe a set of engagement 1 for hydraulic transmission system 2.

With reference to FIGS. 2 and 3, a hydraulic transmission system 2 comprises a hydraulic machine 201, a hydraulic circuit 21 connected to the hydraulic machine 201, said hydraulic circuit 21 comprising a high pressure line 211, and a booster pump 23 configured for load the hydraulic circuit 21, as well as to drive, in parallel, hydraulic actuators (not shown). The hydraulic circuit 21 may comprise a hydraulic consumer 200, such as a load or any type of consumer and / or receiver of hydraulic power such as machine tools or hydraulic movements (not shown), but also such as another hydraulic machine 202, as described more precisely with reference to FIG. 3. In any event, the hydraulic circuit comprises a charging or booster circuit 22 connected to the inlet or outlet of the hydraulic machine 201.

FIGS. 2 and 3 illustrate an exemplary embodiment of such a charging circuit 22, which includes booster check valves 230 and pressure relief valves 231, as well as a connection 232 to the booster pump 23 II is however, note that other embodiments are possible, since such a charging circuit 22 is well known to those skilled in the art. The hydraulic machines 201, 202 can be of the axial type, or of the radial type. In addition, the hydraulic machines 201, 202 can be of fixed or variable displacement.

In an embodiment illustrated in FIG. 3, a first hydraulic machine 201 can first of all be configured to transmit power to the hydraulic circuit, from a torque supplied by a drive element 4. To do this, the high pressure line 211 is connected to the discharge of the hydraulic machine 201 which delivers a pressurized hydraulic fluid there when it is coupled to the drive element 4. In this case, the hydraulic machine 201 operates as a power pump. The drive element 4 can then be a towing axle of the vehicle 41, a drive shaft of the vehicle (not shown), or a power take-off of the vehicle (not shown).

Consequently, the second hydraulic machine 202 can be configured to transmit a torque to an element to be driven 5, from the hydraulic circuit 21. In this case, the high pressure line is connected to the intake of the hydraulic machine 201 which transforms the pressure of the fluid flowing therein, in useful torque for the element to be driven 5. In this case, the hydraulic machine 202 operates as a hydraulic motor. The element to be driven 5 can then be a carrier axle 51 of the vehicle, for example the axle of a trailer when such a system 2 is disposed within a construction vehicle, with a view to enabling it to evolve better. controlled in unstable environments, such as on sand.

In a variant (not shown), the hydraulic circuit is an open circuit and comprises two hydraulic machines connected to a hydraulic tank, at ambient pressure. The operation of the first hydraulic machine causes the circulation of fluid from the reservoir to the high pressure line, and the operation of the second hydraulic machine causes the circulation of fluid from the high pressure line to the hydraulic tank. In addition, the first hydraulic machine can be connected to a drive element, and the second hydraulic machine can be connected to a drive element, at least one of the machines (or a machine) being connected via 'a set of commitment.

In another variant, with reference to FIG. 3, the hydraulic circuit is a closed circuit. The hydraulic circuit fluidly connects a first hydraulic machine 201 to a second hydraulic machine 202, via a first line 211 and a second supply line 212. The hydraulic circuit 21 is supplied with hydraulic fluid by means of 'a booster pump 23 to which it is fluidly connected.

Such a hydraulic transmission system 2 can for example be implemented, in the variant illustrated in FIG. 3, to repeat the movement of an axle 41 on another axle 51. In this case, each hydraulic machine 201, 202 is fixed displacement, and the speed ratio between the first hydraulic machine 201 and the second hydraulic machine 202 is constant. In this variant, the first axle 41 is a tractor, that is to say that it is itself driven by the engine of the vehicle (not shown). In such a variant, the hydraulic transmission system 2 is for example used to switch from a two-wheel drive transmission to a four-wheel drive transmission, in order to provide better grip to the vehicle.

In another variant, illustrated in FIG. 2, the drive element 4 is a drive shaft. The first hydraulic machine 201 is then driven directly by the transmission shaft 4, for example at the outlet of the vehicle gearbox. The second hydraulic machine 202 drives a non-towing axle of the vehicle (not shown), also with a view to providing better grip.

In a third variant (not shown), the drive element is a power take-off driving the first hydraulic machine. The PTO is an auxiliary power output of the engine or an output of a vehicle gearbox, that is to say that it is not linked to an axle of the vehicle. This provides a progressive hydraulic PTO. The second hydraulic machine drives a non-tractor carrying axle

The engagement assembly 1 comprises a clutch device 3 configured to couple between the hydraulic machine 201, 202 on the one hand and the drive element 4 or the element to be driven 5 on the other hand.

The engagement assembly 1 further comprises a first hydraulic clutch control 31 configured to be connected to a booster pump 23, for example the booster pump 23 for charging the hydraulic circuit 21. More precisely, the first hydraulic control 31 is configured to ensure partial engagement of the clutch device 3, so that part of the torque supplied by the hydraulic machine 202, or by the drive element 3, is transmitted via the device clutch 3. The partial engagement of the clutch device 3 ensures, in the case where the hydraulic machine 201 is a power pump, a first pressurization, which is a partial pressurization, of the high pressure line 211.

The booster pump 23 can for example, and without limitation, be an electric pump. In this case the booster pump 23 rotates independently of the drive element 4. The booster pump 23 can also be formed by a disengageable pump controlled and driven by a heat engine. Alternatively, as visible in FIG. 2, the booster pump 23 can be mechanically driven by the drive element 4. In this case, the booster pump 23 is preferably followed by a directional valve controlled, by example with two positions and three ways (not shown). Moreover, the coupling of the booster pump 23 with the drive element 4 can also be implemented by a clutch device identical to the clutch device 3 coupling the hydraulic machine 201 to the element of training 4.

Furthermore, the engagement assembly 1 comprises a second hydraulic clutch control 32 configured to be connected to the high pressure line 211. This connection is advantageous once the high pressure line 211 is pressurized. This can be implemented by the partial engagement of the clutch device 3 by the first hydraulic clutch control 31, when the hydraulic machine 201 is a power pump. In this case, the partial engagement of the clutch device 3 in fact ensures the pressurization of the high pressure line 211 which supplies the second hydraulic control 32. More specifically, the second hydraulic control 32 is configured to ensure full engagement of the clutch device 3, so that the entire torque supplied by the hydraulic machine 202, or by the drive element 4, is transmitted via the clutch device 3.

In a preferred embodiment, as shown in FIGS. 2 and 3, the clutch device 3 comprises a first part of coupling elements 6 connected to the hydraulic machine 201, 202, and a second part of coupling elements 6 connected to the drive element 4 or to the element to be driven 5. The engagement of the coupling elements 6 ensures the engagement of the clutch device

3.

The coupling elements 6 may for example be a set of friction clutch discs 6 urged by return elements 8, such as springs, to be spaced from each other at rest. The engagement of these discs 6, opposing the biasing of the return elements 8, ensures the coupling of the hydraulic machine 201, 202 and the drive element 4 or the element to be driven 5. This embodiment of a clutch device 3 with friction discs is not, however, limiting, since it is also possible, according to other variants, for the clutch device 3 to be drum or conical or with dogs (training fingers).

In a preferred variant illustrated more precisely in FIG. 3, the first hydraulic clutch control 31 comprises a first chamber 310, and the second hydraulic clutch control 32 comprises a second chamber 320, the first chamber 310 preferably being independent of the second chamber 320. The pressure in each of the chambers 310, 320 controls the movement of a piston 7 which opposes the stressing of the return elements 8. As can be seen in FIG. 3, the return elements 8 can thus stress the piston 7 so that, at rest, it remains away from the clutch discs by friction 6.

The engagement and disengagement of the clutch device 3 is controlled by the movements of the piston 7. In a first position, the piston 7 does not stress the coupling elements 6, while in a second position, the piston 7 ensures their engagement. The positioning of the piston 7 is controlled by the first hydraulic control 31 and by the second hydraulic control 32.

When the first chamber 310 is supplied by the booster pump 23, the booster pressure is established in the first chamber 310, and the piston 7 requests the engagement of the coupling elements 6, which is however only partial. Thus, only part of the torque supplied by the hydraulic machine 202 or the drive element 4, can effectively be transmitted via the clutch device 3. However, this partial coupling is not sufficient to ensure the transmission of the entire couple. Consequently, the second chamber 32 takes over via a supply via the high pressure line 211 of the hydraulic circuit 21. An operating pressure of the hydraulic circuit 21 is then established in the second chamber 320, and the piston 7 requests the activation taking of the coupling elements 6 with forces much greater than the stressing forces of the first chamber 31. By way of nonlimiting example, the booster pressure being between 3 and 30 bars, typically equal to 20 bars, and the pressure of operating within the high pressure line being between 200 and 600 bars, typically equal to 400 bars, the coupling forces following the piloting of the second hydraulic control 320 are approximately ten times greater than the partial coupling forces following the piloting of the first hydraulic control 310. Thus, the entire torque supplied by the hydraulic machine 202 or the drive element 4, can effectively be be transmitted via the clutch device 3, and this without the need to oversize the coupling elements 6.

Other means for pressurizing the first hydraulic control 31 can also be envisaged. Thus, in a variant not shown, a piloted directional valve alternately connects the first hydraulic control 31 to the booster pump outlet 23 or to the reservoir 24. This directional valve can for example be a solenoid valve piloted with two inputs and one output.

In any event, the declutching of the hydraulic machine 201, 202 (ie the disengagement of the clutch device 3) is ensured by draining the hydraulic clutch controls 31, 32, that is to say at the first chamber 310 and second chamber 320. This can be done via drains 33 and a vacuum valve 330, or any means for resetting the pressure in the high lines pressure 211 and pressure base 212 of the hydraulic circuit 21. As illustrated in FIG. 3, the vacuum valve 330 makes it possible to zero the pressure in the high pressure line 211 and therefore in the low pressure line 212, but also in booster pump outlet 23 by the non-return valves 230 of the booster assembly 22. In this way, the first hydraulic control 31 is also placed under vacuum.

Switching off the booster pump 23 (for example by stopping an electric pump, for a circuit of the type illustrated in FIG. 3, or by disconnection of the drive element 4, for example for a circuit of the type illustrated in FIG. 2) combined with the natural leaks of the hydraulic components can also be implemented for the declutching of the hydraulic machine 201, 202. Indeed, this cut and these leaks drive a drop in pressure within the hydraulic controls 31, 32 which leads to a slackening of the clutch device. Alternatively, as illustrated in FIG. 3, stopping the electric pump 23 followed by activating the vacuum valve 330 allows faster disengagement.

In one embodiment, the clutch device 3 is integrated into the hydraulic machine 201, 202. Alternatively, the clutch device 3 can also be fixed to the drive element 4, for example a transmission shaft or a PTO, or the element to be driven 5.

In a variant of the transmission system 2 described, as visible in FIG. 3, each engagement assembly 1 further comprises a high pressure selector 10, configured to ensure the fluid connection between the second hydraulic control 32 and that of the first 211 or the second line 212 which is the high pressure line. In fact, depending on the variant of the hydraulic transmission system 2, it is possible that the first hydraulic machine 201 operates in hydraulic pump mode and the second hydraulic machine 202 operates in hydraulic motor mode, and vice versa, depending in particular on the need for additional traction. on the corresponding axles 41, 51 of the vehicle, and / or of the forward or reverse travel of said vehicle. In operation, the high pressure line 211 can therefore alternately correspond to the first 211 or to the second supply line 212. In any event, the high pressure selector 10 authorizes the supply of the second hydraulic control 32 from that of the first 211 or second 212 supply line within which the pressure is the greatest.

With reference to FIG. 3, a method E for engaging a hydraulic transmission system 2 of a vehicle, said method E being implemented by an assembly 1 according to any one of the embodiments previously described, comprises the stages of:

supply E1 of the first hydraulic control 31 of the clutch device 3 by means of the booster pump 23 so as to ensure partial engagement of the clutch device 3, and

- E2 supply the second hydraulic control 32 of the clutch device 3 by means of the high pressure line 211 so as to ensure complete engagement of the hydraulic device 3.

More generally, in a vehicle or equipment provided with an engagement assembly 1 according to any one of the embodiments described above, the engagement of the hydraulic transmission system 2 is implemented by means of a reduced pump (ie, the booster pump 23), at a lower pressure, which reduces the energy consumption due to the booster pump 23, and makes it possible to reduce the size of the booster pump 23, while ensuring thereafter a clutch and a high transmitted power (ie high transmitted torque and high pressure in the high pressure line 211). This allows in particular better engagement of the clutch device 3, which makes it possible to free up the additional dimensioning possibilities of the clutch device 3 (eg diameter, thickness, and number of friction discs 6) so as not to be in the obligation to oversize the coupling elements 6 to transmit large torques. The clutch device 3 can therefore advantageously be reduced. This also makes it possible to engage the hydraulic transmission system 2 before the pressure is completely established in the hydraulic circuit 21, which makes the clutch device 3 faster, while ensuring progressive coupling. In addition, the noise pollution and the resistant torque are limited when the hydraulic machine 201, 202 is decoupled. An engagement assembly 1 arranged on a clutch device 3 coupled to a drive shaft makes it possible to avoid jolts and noise. Finally, such an engagement system 1 has the following advantage: the more the torque to be transmitted increases, the more the control pressure, and therefore the tightening of the clutch device 3, increases.

Claims (15)

1. Engagement assembly (1) for a hydraulic transmission system (2), said system (2) comprising: - a hydraulic machine (201, 202), and - a hydraulic circuit (21) comprising a high pressure line (211), the engagement assembly (1) comprising: - a clutch device (3) configured to ensure coupling between the hydraulic machine (201, 202) on the one hand, and a drive element (4) or an element to be driven (5) on the other hand, - A first hydraulic clutch control (31) configured to be connected to a booster pump (23), the engagement assembly (1) being characterized in that it comprises a second hydraulic clutch control (32 ) configured to be connected to the high pressure line (211). 2. Engagement assembly (1) according to claim 1, in which: - the first hydraulic control (31) is configured to ensure partial engagement of the clutch device (3), so that part of the torque supplied by the hydraulic machine (202), or by the drive element ( 4), is transmitted via the clutch device (3), and - the second hydraulic control (32) is configured to ensure complete engagement of the clutch device (3), so that all of the torque supplied by the hydraulic machine (202), or by the drive element (4 ), is transmitted via the clutch device (3). 3. Engagement assembly (1) according to one of claims 1 or 2, in which: the first hydraulic clutch control (31) comprises a first chamber (310), and - the second hydraulic clutch control (32) comprises a second chamber (320), the first chamber (310) being independent of the second chamber (320). 4. Engagement assembly (1) according to one of claims 1 to 3, further comprising a piloted directional valve, configured to connect the first hydraulic control (31) alternately to the booster pump outlet (23) or to an atmospheric pressure tank (24). 5. Engagement assembly (1) according to one of claims 1 to 4, wherein the hydraulic circuit is closed circuit and comprises a first line (211) and a second line (212), the assembly further comprising a high pressure selector (10), configured to ensure the fluid connection between the second hydraulic control (32) and that of the first (211) or the second line (212) which is the high pressure line. 6. Engagement assembly (1) according to one of claims 1 to 5, wherein the hydraulic machine (201) is a power pump connected to a drive element (4). 7. Engagement assembly (1) according to claim 6, wherein the drive element (4) is an axle of the vehicle. 8. Engagement assembly (1) according to one of claims 6 or 7, wherein the drive element (4) is a drive shaft of the vehicle. 9. Engagement assembly (1) according to one of claims 6 to 8, wherein the drive element (4) is a PTO of the vehicle. 10. Engagement assembly (1) according to one of claims 1 to 5, wherein the hydraulic machine (202) is a hydraulic motor connected to a drive element (5). 11. Engagement assembly (1) according to claim 10, in which the element to be driven (5) is an axle of the vehicle. 12. Engagement assembly (1) according to one of claims 1 to 11, the engagement assembly (1) being further configured to be integrated into the hydraulic machine (201, 202). 13. Vehicle comprising an engagement assembly (1) according to one of claims 1 to 12. 5 14. Method for engaging (E) a hydraulic transmission system (2) of a vehicle, said system (2) comprising: - a hydraulic machine (201, 202), and - a hydraulic circuit (21) comprising a high pressure line (211), the method (E) being implemented by means of an engagement assembly (1) 10 according to one of claims 1 to 12, the method (E) comprising the steps of: - supply (E1) of the first hydraulic clutch control (31) of the clutch device (3) by means of the booster pump (23) so as to ensure partial engagement of the clutch device (3), and 15 - supply (E2) of the second hydraulic control (32) of the clutch device (3) by means of the high pressure line (211) so as to ensure complete engagement of the hydraulic device (3).