Control of freewheel valves

Abstract

The invention relates to an assembly for a traction assist hydraulic circuit of a vehicle, comprising: a freewheel valve (1); a hydraulic pilot valve (2) connected to the freewheel valve (1) and configured to drive the freewheel valve (1); and a reversing solenoid valve (3) connected to the hydraulic pilot valve (2) and configured to control the hydraulic pilot valve (2).

Description

Technical Field

[0001] The present disclosure relates to the field of hydraulic assistance for vehicle towing. More specifically, the present disclosure relates to the control of a freewheel valve within a hydraulic circuit for assisting vehicle towing. Background Art

[0002] In a hydraulic circuit for assisting vehicle towing, at least one hydraulic motor can be engaged with at least one wheel when additional motor force is required to drive at least one wheel, for example when the vehicle is traveling on rough or slippery ground. Once the vehicle is moving at a high enough speed or the traffic conditions result in a large enough motor force, the motor may be disengaged from the wheel.

[0003] For this purpose, the hydraulic circuit is generally equipped with a freewheel valve, whose different positions allow the engagement and disengagement of the motor. The different positions are usually commanded by a control valve. The control valve is typically a directionally controlled electrohydraulic valve.

[0004] Certain motors are adapted to be disengaged by retraction of the motor's piston. For this purpose, the inlet and / or discharge orifices of the motor must be connected to the reservoir of the hydraulic circuit or to a pressurizing circuit via the freewheel valve and the control valve. The engagement and disengagement of the motor must be achievable quickly enough, especially when the vehicle is in motion and the motor continues to operate during engagement or disengagement. This execution speed is particularly useful for minimizing mechanical shock, torque vibrations, engine wear, pressure peaks, and noise. Therefore, the flow rate circulating through the control valve is very high, which requires a significant amount of energy to switch it.

[0005] Therefore, such control valves are very heavy and bulky, especially because they are equipped with large solenoids to command their operation. In addition, such control valves are costly and consume a large amount of energy. For example, such control valves can typically be operated with a current greater than 2.5 A and an electrical power greater than 30 W. Summary of the Invention

[0006] An object of the present invention is to allow the freewheel valve to be controlled in a cheaper and more energy-efficient manner.

[0007] To this end, according to one aspect of the present disclosure, there is provided a component for a hydraulic circuit for assisting vehicle towing, the component comprising: a freewheel valve; a hydraulic control valve connected to the freewheel valve and configured to control the freewheel valve; and a directionally controlled electric valve connected to the hydraulic control valve and configured to control the hydraulic control valve.

[0008] The hydraulic control valve may include: a first inlet port configured to be connected to the reservoir of the circuit; a second inlet port configured to be connected to the pressurizing line of the circuit; and an outlet port connected to the control chamber of the freewheel valve and the second inlet port.

[0009] The hydraulic control valve may further include a slider and a body, the slider being movable within the body between a first position and a second position. In the first position, the slider allows fluid to circulate between a first inlet port and an outlet port of the hydraulic control valve and prohibits fluid from circulating between a second inlet port and the outlet port of the hydraulic control valve; in the second position, the slider allows fluid to circulate between the second inlet port and the outlet port of the hydraulic control valve and prohibits fluid from circulating between the first inlet port and the outlet port of the hydraulic control valve.

[0010] The hydraulic control valve may further include: a control chamber connected to the reversing electric valve and to the slider of the hydraulic control valve such that the pressure in the control chamber exerts a first force on the slider of the hydraulic control valve; and a return element connected to the slider and the body of the hydraulic control valve to exert a second force on the slider of the hydraulic control valve; wherein the movement of the slider of the hydraulic control valve between the first position and the second position of the hydraulic control valve is controlled by the difference between the first force and the second force on the slider of the hydraulic control valve.

[0011] The reversing electric valve may include: a first inlet port configured to be connected to a reservoir of the circuit; a second inlet port configured to be connected to a pressurized line of the circuit; and an outlet port connected to the control chamber of the hydraulic control valve.

[0012] The reversing electric valve may further include a slider and a body, the slider being movable within the body between a first position and a second position. In the first position, the slider allows fluid to circulate between the first inlet port and the outlet port of the reversing electric valve and prohibits fluid from circulating between the second inlet port and the outlet port of the reversing electric valve; in the second position, the slider allows fluid to circulate between the second inlet port and the outlet port of the reversing electric valve and prohibits fluid from circulating between the first inlet port and the outlet port of the reversing electric valve.

[0013] The reversing electric valve may further include a solenoid configured to exert a first force on the slider of the reversing electric valve; and a return element connected to the slider and the body of the reversing electric valve to exert a second force on the second slider of the reversing electric valve; wherein the movement of the slider of the reversing electric valve between the first position and the second position of the reversing electric valve is controlled by the difference between the first force and the second force on the slider of the reversing electric valve.

[0014] The freewheel valve may include: a first inlet port configured to connect to a first orifice of a hydraulic pump of a circuit; a second inlet port configured to be alternately connected to a reservoir of the circuit or a boost line of the circuit via a hydraulic control valve; a third inlet port configured to connect to a second orifice of the pump; a first outlet port configured to connect to a first orifice of a hydraulic motor of the circuit; and a second outlet port configured to connect to a second orifice of the motor.

[0015] The freewheel valve may further include a slider and a body, the slider being movable within the body between a first position and a second position. In the first position, the slider allows fluid to circulate between the second inlet port of the freewheel valve and each of the first and second outlet ports, and prohibits fluid from circulating between each of the first inlet port and the third inlet of the freewheel valve and each of the first and second outlet ports. In the second position, the slider allows fluid to circulate between the first inlet port and the first outlet port of the freewheel valve and between the third inlet port and the second outlet port, and prohibits fluid from circulating between the first inlet port and the second outlet port of the freewheel valve, between the second inlet port and each of the first and second outlet ports, and between the third inlet port and the first outlet port.

[0016] The freewheel valve may further include: a control chamber connected to the hydraulic control valve and to the slider of the freewheel valve such that the pressure in the control chamber exerts a first force on the slider of the freewheel valve; and a return element connected to the slider and to a third body of the freewheel valve so as to exert a second force on the slider of the freewheel valve;

[0017] wherein the movement of the slider of the freewheel valve between the first and second positions of the freewheel valve is controlled by the difference between the first force and the second force on the slider of the freewheel valve.

[0018] A freewheel valve may include: a first inlet port configured to connect to a first orifice of a hydraulic pump of a circuit; a second inlet port configured to be alternately connected to a reservoir of the circuit or a boost line of the circuit via a hydraulic control valve; a third inlet port configured to connect to a second orifice of the pump; a first outlet port configured to connect to a first orifice of a hydraulic motor of the circuit; a second outlet port configured to connect to a second orifice of the motor; a sliding member and a body, the sliding member being movable within the body between a first position and a second position, in the first position, the sliding member allows fluid to circulate between the second inlet port of the freewheel valve and each of the first outlet port and the second outlet port, and prohibits fluid from circulating between each of the first inlet port and the third inlet port of the freewheel valve and each of the first outlet port and the second outlet port; in the second position, the sliding member allows fluid to circulate between the first inlet port and the first outlet port of the freewheel valve and between the third inlet port and the second outlet port, and prohibits fluid from circulating between the first inlet port and the second outlet port of the freewheel valve, between the second inlet port and each of the first outlet port and the second outlet port, and between the third inlet port and the first outlet port; a control chamber connected to the hydraulic control valve and to the sliding member of the freewheel valve such that the pressure in the control chamber exerts a first force on the sliding member of the freewheel valve; and a return element connected to the sliding member of the freewheel valve and a third body to exert a second force on the sliding member of the freewheel valve; wherein, the movement of the sliding member of the freewheel valve between the first position and the second position of the freewheel valve is controlled by the difference between the first force and the second force on the sliding member of the freewheel valve. The hydraulic control valve may include: a first inlet port configured to connect to a reservoir of the circuit; a second inlet port configured to connect to a boost line of the circuit; an outlet port connected to the control chamber of the freewheel valve and the second inlet port; and a sliding member and a body, the sliding member being movable within the body between a first position and a second position, in the first position, the sliding member allows fluid to circulate between the first inlet port and the outlet port of the hydraulic control valve and prohibits fluid from circulating between the second inlet port and the outlet port of the hydraulic control valve; in the second position, the sliding member allows fluid to circulate between the second inlet port and the outlet port of the hydraulic control valve and prohibits fluid from circulating between the first inlet port and the outlet port of the hydraulic control valve; and wherein, in the first position of the sliding member of the freewheel valve and the second position of the sliding member of the freewheel valve, the freewheel valve and the hydraulic control valve are configured to connect the boost line to the control chamber of the freewheel valve and the motor.

[0019] A freewheel valve may include: a first inlet port configured to connect to a first orifice of a hydraulic pump of a circuit; a second inlet port configured to be alternately connected to a reservoir of the circuit or a boost line of the circuit via a hydraulic control valve; a third inlet port configured to connect to a second orifice of the pump; a first outlet port configured to connect to a first orifice of a hydraulic motor of the circuit; a second outlet port configured to connect to a second orifice of the motor; a slider and a body, the slider being movable within the body between a first position and a second position, in the first position, the slider allows fluid to circulate between the second inlet port of the freewheel valve and each of the first outlet port and the second outlet port, and prohibits fluid from circulating between each of the first inlet port and the third inlet port of the freewheel valve and each of the first outlet port and the second outlet port; in the second position, the slider allows fluid to circulate between the first inlet port and the first outlet port of the freewheel valve and between the third inlet port and the second outlet port, and prohibits fluid from circulating between the first inlet port and the second outlet port of the freewheel valve, between the second inlet port and each of the first outlet port and the second outlet port, and between the third inlet port and the first outlet port; a control chamber connected to the hydraulic control valve and to the slider of the freewheel valve such that the pressure in the control chamber exerts a first force on the slider of the freewheel valve; and a return element connected to the slider and a third body of the freewheel valve to exert a second force on the slider of the freewheel valve; wherein the movement of the slider of the freewheel valve between the first position and the second position of the freewheel valve is controlled by the difference between the first force and the second force on the slider of the freewheel valve. The hydraulic control valve may include a first inlet port configured to connect to a reservoir of the circuit; a second inlet port configured to connect to a boost line of the circuit; and an outlet port connected to the control chamber of the freewheel valve and the second inlet port; and wherein the assembly further includes a line connecting the outlet port of the control valve to the control chamber of the freewheel valve, the line including a nozzle configured to adjust the flow rate from the boost line.

[0020] The hydraulic control valve may further include a slider and a body, the slider being movable within the body between a first position and a second position, in the first position, the slider allows fluid to circulate between the first inlet port and the outlet port of the hydraulic control valve, and prohibits fluid from circulating between the second inlet port and the outlet port of the hydraulic control valve; in the second position, the slider allows fluid to circulate between the second inlet port and the outlet port of the hydraulic control valve, and prohibits fluid from circulating between the first inlet port and the outlet port of the hydraulic control valve.

[0021] The hydraulic control valve may further include: a control chamber connected to the reversing electric valve and to the slider of the hydraulic control valve such that the pressure in the control chamber exerts a first force on the slider of the hydraulic control valve; and a return element connected to the slider and the body of the hydraulic control valve so as to exert a second force on the slider of the hydraulic control valve; wherein the movement of the slider of the hydraulic control valve between a first position and a second position of the hydraulic control valve is controlled by the difference between the first force and the second force on the slider of the hydraulic control valve.

[0022] The reversing electric valve may include: a first inlet port configured to be connected to a reservoir of the circuit; a second inlet port configured to be connected to a pressurization line of the circuit; and an outlet port connected to the control chamber of the hydraulic control valve.

[0023] The reversing electric valve may further include a slider and a body, the slider being movable within the body between a first position and a second position, in the first position, the slider allowing fluid to circulate between the first inlet port and the outlet port of the reversing electric valve and prohibiting fluid from circulating between the second inlet port and the outlet port of the reversing electric valve; in the second position, the slider allowing fluid to circulate between the second inlet port and the outlet port of the reversing electric valve and prohibiting fluid from circulating between the first inlet port and the outlet port of the reversing electric valve.

[0024] The reversing electric valve may further include: a solenoid configured to exert a first force on the slider of the reversing electric valve; and a return element connected to the slider and the body of the reversing electric valve so as to exert a second force on the second slider of the reversing electric valve; wherein the movement of the slider of the reversing electric valve between a first position and a second position of the reversing electric valve is controlled by the difference between the first force and the second force on the slider of the reversing electric valve.

[0025] According to another aspect of the present invention, there is provided a hydraulic circuit for assisting vehicle traction, the circuit including: a hydraulic motor configured to be coupled to a wheel of a vehicle; a hydraulic pump; and a component according to the present disclosure; wherein a freewheel valve is configured to control fluid circulation between the pump and the motor.

[0026] The pump may include a first orifice and a second orifice, and the hydraulic motor includes a first orifice and a second orifice, the circuit further including: a communication circuit connecting the first orifice of the pump to the first orifice of the motor and connecting the second orifice of the pump to the second orifice of the motor, the communication circuit including a freewheel valve; a reservoir; a boost pump including an inlet orifice and a discharge orifice connected to the reservoir; and a pressurization line connected to the discharge orifice of the boost pump and the communication circuit; wherein the freewheel valve and the hydraulic control valve are configured to control fluid circulation between, on the one hand, the motor and, on the other hand, the pump, the pressurization line, and / or the reservoir.

[0027] The hydraulic control valve can be configured to allow fluid to circulate between the motor and the boost pipeline and / or the reservoir at a flow rate of 50 to 100 liters per minute.

[0028] The engagement time and / or disengagement time of the motor can be less than 1 second, preferably less than 0.5 second.

[0029] The reversing electric valve can be configured to consume less than 20 W of electric power to control the hydraulic control valve.

[0030] According to another aspect of the present disclosure, there is provided a vehicle including: a main shaft for supporting at least one drive wheel of the vehicle; a countershaft separated from the main shaft; a wheel mounted on the countershaft; and a circuit according to the present disclosure, wherein the motor is coupled to the wheel.

[0031] According to another aspect of the present disclosure, there is provided a method for controlling a vehicle including a main shaft for supporting at least one drive wheel of the vehicle, a countershaft separated from the main shaft, and a wheel mounted on the countershaft, the method comprising:

[0032] The reversing electric valve controls the hydraulic control valve; and

[0033] The hydraulic control valve controls the freewheel valve of the hydraulic motor of the vehicle coupled to the wheel;

[0034] wherein the enabling of the reversing electric valve causes the enabling of the hydraulic control valve, so that the freewheel valve can first set fluid circulation between the motor and the boost pipeline of the vehicle, and then set fluid circulation between the hydraulic pump and the motor of the vehicle; and

[0035] wherein the disabling of the reversing electric valve causes the disabling of the hydraulic control valve, thereby disabling the freewheel valve to isolate the pump from the motor and connecting the motor of the vehicle to the reservoir through the hydraulic control valve. Description of the Drawings

[0036] Other features, objectives, and advantages will become apparent from the following purely illustrative and non - limiting description. This description must be read in conjunction with the Figure 1 which schematically shows a hydraulic circuit for assisting vehicle traction. Detailed Description

[0037] A vehicle is generally equipped with at least one main shaft that supports at least one driving wheel of the vehicle. The driving wheel allows the vehicle to move, for example, on land. Of course, the vehicle may include multiple main shafts and multiple driving wheels. In addition, the vehicle may include at least one auxiliary shaft that supports at least one other wheel 42 (non-driving wheel) of the vehicle. Of course, the vehicle may include multiple auxiliary shafts and multiple non-driving wheels 42. Although the wheels 42 are not driving wheels, they can still play a role in the driving of the vehicle, such as by supporting the load of the vehicle or providing steering of the vehicle.

[0038] The vehicle may be an agricultural engine or a construction site engine, such as a combine harvester or a grader. The vehicle may be an articulated vehicle or a towed vehicle, including a tractor part and a towed (or pushed) part, such as a trailer or a tool with towed (or pushed) wheels.

[0039] Figure 1 It is shown that the vehicle may further include a hydraulic circuit that includes a hydraulic pump 43. The hydraulic pump 43 may be driven directly or indirectly by the main motor of the vehicle, typically through a power take-off device connected to the main motor, and the power take-off device can be connected to the hydraulic pump 43 through a clutch. The main motor of the vehicle may include an internal combustion engine and / or an electric motor. The hydraulic pump 43 includes at least two orifices 431, 432 connected to a communication circuit 40. The communication circuit 40 includes a high-pressure pipeline in the outflow direction of the hydraulic pump 43 and a low-pressure pipeline in the suction direction of the hydraulic pump 43. The flow direction within the communication circuit 40 can be changed. This modification can be achieved by using a flow direction reversal pump 43 to reverse the driving direction of the pump 43 and / or by providing a direction reversal valve within the communication circuit 40.

[0040] In operation, the pressure set within the communication circuit 40 can be between 0 and 600 bar (i.e., 600×10 5 Pa), typically between 0 and 500 bar (i.e., 500×10 5 Pa). To supply fluid to the communication circuit 40 and compensate for many losses, a boost pipeline 400 is connected to the communication circuit 40. The boost pipeline 400 is connected to the communication circuit 40, for example, through Figure 1 a check valve 46 visible in the figure. Usually, the check valve 46 is arranged at the interface between the boost pipeline 400 and the high-pressure pipeline, and the check valve 46 is arranged at the interface between the boost pipeline 400 and the low-pressure pipeline. As described in more detail below, the pressure set within the boost pipeline 400 is also used as a hydraulic control pressure to operate the valves 1, 2 of the circuit. This boost pressure is between 5 and 20 bar (i.e., between 5.0×10 5 and 20×10 5 Pa), and typically has a value of 15 bar (i.e., 15×10 5Pa). The pressurizing line 400 itself is supplied by a pressurizing pump 45 which sucks fluid from the hydraulic reservoir 44 through its inlet orifice and discharges fluid through its discharge orifice through the pressurizing line 400. The hydraulic reservoir 44 or non-pressurized reservoir 44 is substantially at atmospheric pressure and defines the zero pressure reference of the circuit. The pressurizing pump 45 itself can be driven by the main motor of the vehicle through a power take-off device, for example the same drive device as the hydraulic pump 43, as Figure 1 shown. The pressurizing pump 45 can also be integrated into the hydraulic pump 43. Alternatively, the pressurizing pump 45 can be driven by an electric pump unit. The hydraulic reservoir 44 is particularly provided to collect fluid from all the leaks in the circuit. Figure 1 A pressure regulating valve 47 is also shown which is used to regulate the pressure in the pressurizing line 400 regardless of the operating mode of the pressurizing pump 45 and generally regardless of the speed of the main motor of the vehicle.

[0041] This circuit is in particular used to assist the traction of the non-driven wheels 42. More precisely, this circuit can be used to temporarily supply a remaining torque to at least one non-driven wheel 42 of the vehicle. This remaining torque is particularly necessary when the vehicle is moving on uneven or slippery ground. In this case, the driving wheels actually slip, which combined with a reduction in the torque provided by the main shaft results in a reduction in the traction of the vehicle. In other words, this circuit makes it possible to temporarily increase the number of driving wheels of the vehicle. In addition, the circuit is configured to disable its assistance when it is no longer necessary to supply a remaining motor force to the wheels. The vehicle can include at least one or even more secondary shafts assisted by the circuit or even by several circuits similar to Figure 1 shown. Generally, there is one circuit per non-driven wheel 42 or one circuit per secondary shaft. In any case, the vehicle can thus include secondary shafts which are assisted in the working mode of the vehicle, for example in the field or on a construction site, and the assistance of which is disengaged in the road mode (for example when the vehicle is moving on a road surface).

[0042] As Figure 1 shown, the remaining torque is provided by the hydraulic motor 41 of the circuit which is connected (or coupled) to the wheel 42. Due to the presence of the hydraulic pump 43, the hydraulic motor 41 is able to supply a remaining torque to the wheel 42. The hydraulic pump 43 can have a structure and operation similar or dissimilar to that of the hydraulic motor 41. The hydraulic motor 41 includes at least two orifices 411, 412 to which the orifices 431, 432 of the hydraulic pump 43 are connected through a communication circuit 40. In this way, the hydraulic pump 43 can output fluid through the hydraulic motor 41 through the communication circuit 40, which allows the hydraulic motor 41 to generate a remaining torque that will be transmitted to the wheel 42. Figure 1The part of the connecting circuit 40 that shows the connection of the hydraulic pump 43 to the hydraulic motor 41 is closed, that is, all the fluid that circulates through the hydraulic motor 41 by the output of the hydraulic pump 43 returns to the hydraulic pump 43 before being sent to the hydraulic motor 41 again. Where applicable, a direction reversal valve in the connecting circuit 40 is arranged between the hydraulic pump 43 and the hydraulic motor 41, upstream or downstream of the freewheel valve 1, which will be described in more detail below. The flow direction of the fluid within this part of the connecting circuit 40 and the determination of the high-pressure line and the low-pressure line depend on the rotational direction of the wheel 42, that is, on whether the vehicle is moving forward or backward, and / or on the type of force transmitted to the wheel 42, that is, whether it is a traction force or a braking force. Generally, back to Figure 1 , if forward movement corresponds to the clockwise circulation of the fluid in the connecting circuit 40, then during traction, the high-pressure line will be connected to the inlet port 113 of the freewheel valve 1, and the low-pressure line will be connected to the inlet port 111 of the freewheel valve 1. Conversely, during braking, the inlet ports 111, 113 will be described in more detail below. Conversely, assuming that the hydraulic pump 43 can reverse its rotational direction, the circulation of the fluid will occur counterclockwise in the connecting circuit 40, and compared with that described for forward movement, the high-pressure line and the low-pressure line will be reversed during traction and braking.

[0043] It must be possible to enable or disable the traction assistance of the wheel 42 according to the needs of the vehicle, usually according to the driver's command, for example, according to the driving conditions of the vehicle. Therefore, it can be stipulated that the assistance is enabled and / or disabled by the engagement and / or disengagement of the hydraulic motor 41, and the hydraulic motor remains connected to the wheel 42. When the hydraulic motor 41 is equipped with pistons, usually when the hydraulic motor 41 is a multi-cam radial piston engine, the engagement and / or disengagement can be achieved by extending and / or retracting the pistons into their respective housings.

[0044] In a multi-cam radial piston engine, usually the disengagement is achieved by isolating the hydraulic motor 41 from the hydraulic pump 43 and by connecting the orifices 411, 412 of the hydraulic motor 41 to the reservoir 44. In doing so, when the wheel 42 drives the hydraulic motor 41, the pistons are pushed back to the retracted position by the cams and / or by the pressure set in the housing of the hydraulic motor 41, and the fluid located below the pistons is discharged towards the reservoir 44. Once in the retracted position, and as long as they remain isolated from the hydraulic pump 43 and connected to the reservoir 44, the pistons will not extend and the cams will then separate from the pistons. The hydraulic motor 41 is then disengaged. Conversely, the engagement is usually achieved by extending the pistons so that they come into contact with the cams, and thus engaging the hydraulic motor 41 with the wheel 42 in order to be able to transmit torque and rotational motion.

[0045] In Figure 1In the circuit shown, a freewheel valve 1 is used to enable and / or disable the assistance. The freewheel valve is arranged within a communication circuit 40 so as to form an interface between a hydraulic motor 41 and a hydraulic pump 43, that is, to control the fluid circulation between the hydraulic pump 43 and the hydraulic motor 41, and also to control the fluid circulation between the hydraulic motor 41 and a reservoir 44 and between the hydraulic motor 41 and a boosting pipeline 400. More precisely, by connecting the hydraulic motor 41 to the boosting pipeline 400 and then to the hydraulic pump 43 (enabled) and / or by connecting the hydraulic motor 41 to the reservoir 44 (disabled), the configuration of the freewheel valve 1 controls the enabling and / or disabling of the assistance for the traction of the wheel 42. Thus, the hydraulic reservoir 44 is provided not only to collect all the leaked fluid from the circuit, but also to collect the remaining fluid from the communication circuit 40 when the assistance is disabled.

[0046] The freewheel valve 1 includes a plurality of inlet ports 111, 112, 113 (three inlet ports 111, 112, 113 in this case) and a plurality of outlet ports 121, 122 (two outlets 121, 122 in this case), and a slider 13 that is movable within a body (not shown) between different positions P5, P6. Each position P5, P6 enables and / or prohibits the fluid circulation between the inlet ports 111, 112, 113 and the outlet ports 121, 122. In addition, the freewheel valve 1 includes a control chamber 14 and a return element 15. The control chamber 14 is arranged to receive fluid until the pressure set within the control chamber 14 generates a force on the slider 13. Similarly, the return element 15 connects the slider 13 to the body so as to apply a force on the slider 13 that opposes the force applied by the pressure set in the control chamber 14. Thus, the movement of the slider 13 within the body is controlled by the difference between the pressure within the control chamber 14 and these opposing forces of the return element 15. In addition, Figure 1 It is shown that any fluid leakage between the slider 13 and the body of the freewheel valve 1 is redirected towards the reservoir 44. Of course, all other leaks in the circuit, such as the internal leaks of the hydraulic pump 43 and the hydraulic motor 41 and the leaks of other components 3, 47, can also be drained into the reservoir 44.

[0047] In the idle position P5 or the default position, the pressure in the control chamber 14 of the freewheel valve 1 is negligible compared to the force exerted by the return element 15 of the freewheel valve 1. The slider 13 of the freewheel valve 1 allows fluid to circulate between one of its two outlet ports 121, 122 and its inlet port 112. Each outlet port is connected to one of the orifices 411, 412 of the hydraulic motor 41, and the inlet port is arranged to be connected to the reservoir 44. The two other inlet ports 111, 113 (each connected to one of the orifices 431, 432 of the hydraulic pump 43) remain blocked. Thus, as long as the orifices 411, 412 of the hydraulic motor 41 are under the pressure of the reservoir 44, the hydraulic motor 41 can discharge at least a part of its fluid into the reservoir 44, and, where applicable, the pistons can retract and then remain in their housings. Therefore, even if the hydraulic motor 41 continues to operate, since it is coupled to the wheel 42 by a cam, no drag torque is transmitted from the hydraulic motor 41 to the wheel 42, so the cam is no longer in contact with the pistons. Then, the traction assist is disabled.

[0048] In the operating configuration, a pressure has been set in the control chamber 14 of the freewheel valve 1, and this pressure is large enough to counteract the force exerted on the slider 13 of the freewheel valve 1 by the return element 15, such that the freewheel valve 1 rotates from the idle position P5 to the working position P6. In this working position, the freewheel valve 1 allows fluid circulation between the hydraulic pump 43 and the hydraulic motor 41. More precisely, in the working position P6, circulation is allowed between each inlet port 111, 113 connected to the orifices 431, 432 of the hydraulic pump 43 and each outlet port 121, 122, and the inlet port 112 arranged to be connected to the reservoir 44 remains blocked. Then, the traction assist is enabled.

[0049] Figure 1 It is shown that the freewheel valve 1 is controlled by a hydraulic control valve 2 connected to the freewheel valve 1.

[0050] The hydraulic control valve 2 is a hydraulically controlled reversing solenoid valve and has a structure similar to that of the freewheel valve 1, except that it only has two inlet ports 211, 212 and an outlet port 221. One inlet port is arranged to be connected to the reservoir 44, the other inlet port is arranged to be connected to the pressure boosting pipeline 400, and the outlet port is arranged to be connected to the control chamber 14 of the freewheel valve 1, preferably through a pipeline including a nozzle 48, and a nozzle is provided to adjust the flow rate from the pressure boosting pipeline 400, which will be described in more detail below.

[0051] In the idle position P1 or the default position, the pressure in the control chamber 24 of the hydraulic control valve 2 is negligible compared to the force exerted by the return element 25 of the hydraulic control valve 2 on the slider of the hydraulic control valve 2. The slider 23 of the hydraulic control valve 2 allows fluid to circulate between its outlet port 221 and the inlet port 211 connected to the reservoir 44, and the other inlet ports 212 remain blocked. Therefore, at least a part of the fluid in the control chamber 14 of the freewheel valve 1 can be discharged, and the set pressure is negligible compared to the force exerted by the return element 15 of the freewheel valve 1 on the slider 13 of the freewheel valve 1. Therefore, the freewheel valve 1 can be switched from its working position P6 to its idle position P5. Furthermore, once the freewheel valve 1 is in its idle position P5, the hydraulic motor 41 can discharge its fluid through the hydraulic control valve 2, so that the traction assist can be disabled. More precisely, the disabling of the hydraulic control valve 2 enables the disabling of the freewheel valve 1. Therefore, the hydraulic motor 41 is isolated from the hydraulic pump 43 and then connected to the reservoir 44 through the freewheel valve 1 and the hydraulic control valve 2, which causes the piston of the hydraulic motor 41 to retract and the wheel 42 to disengage.

[0052] In the operating configuration, a pressure has been set in the control chamber 24 of the hydraulic control valve 2, and this pressure is large enough to counteract the force exerted by the return element 25 of the hydraulic control valve 2 on the slider 23 of the hydraulic control valve 2, so that the slider 23 of the hydraulic control valve 2 moves from the idle position P1 to the working position P2. In this position, as long as the freewheel valve 1 remains in its idle position P5, it allows fluid to circulate between the boost line 400 and the hydraulic motor 41, and also allows fluid to circulate between the boost line 400 and the control chamber 14 of the freewheel valve 1. More precisely, in the working position P2, fluid is allowed to circulate between the inlet port 212 connected to the boost line 400 and the outlet port 221, and the inlet port 211 set to be connected to the reservoir 44 remains blocked.

[0053] This working position P2 of the hydraulic control valve 2 ultimately enables the pressure in the control chamber 14 of the freewheel valve 1 to be set and maintained in order to counteract the force exerted by the return element 15 of the freewheel valve 1 on the slider 15 of the freewheel valve 1, so that the freewheel valve 1 moves from its idle position P5 to its working position P6. More precisely, the enabling of the hydraulic control valve 2 enables the enabling of the freewheel valve 1.

[0054] This operating position P2 of the hydraulic control valve 2 also enables the use of the nozzle 48 to time the switching of the freewheel valve 1 from the idle position P5 to the operating position P6, and to do so in order to facilitate the engagement of the hydraulic motor 41 with the wheel 42. Specifically, by adjusting the flow rate from the pressure boosting line 400, the nozzle 48 enables not only taking into account the characteristics of the control chamber 14 of the freewheel valve 1, but also, at least in the first switching sequence, giving preference to the fluid circulation towards the inlet port 112 of the freewheel valve 1 through which the hydraulic motor 41 is supplied, rather than towards the control chamber 14 of the freewheel valve 1. This enables the piston of the hydraulic motor 41 to be extended and as long as the piston is not in contact with the cam, the pressure in the line connecting the inlet port 112 of the freewheel valve 1 to the hydraulic motor 41 remains low. Once the piston bears on the cam, the pressure in the line connecting the inlet port 112 of the freewheel valve 1 to the hydraulic motor 41 increases until it reaches a level equal to the pressure established in the pressure boosting line 400. Consequently, the flow rate of the fluid towards the hydraulic motor 41 becomes low and a high pressure is set downstream of the nozzle 48 (i.e., within the control chamber 14 of the freewheel valve 1) and in this way the slide 13 of the freewheel valve 1 is switched from the idle position P5 to the operating position P6. Once in the operating position P2, the hydraulic motor 41 is put into communication with the hydraulic pump 43 and this communication is only achieved once the piston has extended. Thus, sequentially, the piston is first extended which allows the hydraulic motor 41 to engage the wheel 42 and then the freewheel valve 1 is switched and secondly, this enables the pressure to be transferred from the hydraulic pump 43 to the hydraulic motor 41.

[0055] Thus, the combination of the freewheel valve 1, the nozzle 48 and the hydraulic control valve 2 enables ensuring that a fluid with a high flow rate is supplied to the hydraulic motor 41 at a boosted pressure and thus its piston is extended more quickly.

[0056] Figure 1 It is shown that the hydraulic control valve 2 is controlled by a reversing electric valve 3 which is connected to the hydraulic control valve 2, more precisely to the control chamber 24 of the hydraulic control valve 2. Specifically, the behavior of the reversing electric valve 3 determines the pressure set within the control chamber 24 of the hydraulic control valve 2 and thus determines the movement of the hydraulic control valve 2 from its idle position P1 (freewheel valve 1 disabled and thus traction assistance disabled) to its operating position P2 (freewheel valve 1 enabled and thus traction assistance enabled).

[0057] The reversing electric valve 3 has a structure similar to that of the hydraulic control valve 2, except that its outlet port 321 is arranged to be connected to the control chamber 24 of the hydraulic control valve 2 and instead of setting a pressure in the control chamber to counteract the force exerted on the slide 33 of the reversing electric valve 3 by the return element 35 of the electric valve, it is by the action of the solenoid 34.

[0058] In the idle position P3 or the default position, the solenoid 34 is disabled, and the slider 33 of the reversing motorized valve 3 allows fluid to circulate between its outlet port 321 and the inlet port 311 connected to the reservoir 44, while the other inlet port 312 remains blocked. In this way, at least a part of the fluid in the control chamber 24 of the hydraulic control valve 2 can be discharged, and the pressure set in the control chamber can be neglected compared to the force exerted on the slider 23 of the hydraulic control valve 2 by the return element 25 of the hydraulic control valve 2. Therefore, the hydraulic control valve 2 can be switched from its working position P2 to its idle position P1 to disable the freewheel valve 1 and the traction assist. More precisely, the disabling of the reversing motorized valve 3 enables the disabling of the hydraulic control valve 2 and thus the disabling of the traction assist.

[0059] In the operating configuration, for example by means of a remote control implemented by the vehicle driver, the solenoid 34 has been enabled, and the force exerted by the solenoid 34 on the slider 33 of the reversing motorized valve 3 has become large enough to counteract the force exerted on the slider 33 of the reversing motorized valve 3 by the return element of the reversing motorized valve 3, so that the slider 33 of the reversing motorized valve 3 moves from the idle position P3 to the working position P4, in which it allows fluid to circulate between the pressurization line 400 and the control chamber 24 of the hydraulic control valve 2. More precisely, in the working position P4, fluid is allowed to circulate between the inlet port 312 connected to the pressurization line 400 and the outlet port 321, while the inlet 311 arranged to be connected to the reservoir 44 remains blocked. This working position P4 of the reversing motorized valve 3 enables the setting and maintenance of the pressure in the control chamber 24 of the hydraulic control valve 2 in order to counteract the force exerted on the slider 23 of the hydraulic control valve 2 by the return element 25 of the hydraulic control valve 2, thereby causing the hydraulic control valve 2 to switch from its idle position P1 to its working position P2. The traction assist can thus be enabled. More precisely, enabling the reversing motorized valve 3 enables the enabling of the hydraulic control valve 2 and thus the enabling of the traction assist.

[0060] To disable the assist, the hydraulic motor 41 must be disengaged.

[0061] To this end, the solenoid 34 is disabled, causing the reversing motorized valve 3 to switch from its working position P4 to its idle position P3, resulting in the control chamber 24 of the hydraulic control valve 2 being placed under the pressure of the reservoir 44. The hydraulic control valve then switches from its working position P2 to its idle position P1. In its idle position P1, the hydraulic control valve 2 enables the pressure identical to that of the reservoir 44 to be set at the orifices 411, 412 of the hydraulic motor 41. As the wheel 42 continues to drive the hydraulic motor 41, the cam and / or pressure within the housing of the hydraulic motor 41 push the piston back and the piston retracts. Until all the pistons are in the retracted position, the flow rate of the fluid discharged from the hydraulic motor 41 through the freewheel valve 1 and the hydraulic control valve 2 towards the reservoir 44 is of the same order of magnitude as the flow rate circulating within the hydraulic motor 41 when the assistance is enabled, when the hydraulic motor 41 is connected to the hydraulic pump 43, and when the rotational speed of the wheel 42 is the rated speed. On the other hand, once all the pistons are retracted and disengaged from the cam, the flow rate circulating from the hydraulic motor 41 towards the reservoir 44 becomes zero.

[0062] Note that in a variant, a system of return members can be provided that defaults to keeping the pistons in the retracted position as long as the orifices 411, 412 of the hydraulic motor 41 are not exposed to the pressure of the fluid discharged by the hydraulic pump 43.

[0063] Thus, whether in its idle position P1 or in its working position P2, the hydraulic control valve 2 is dimensioned to allow the fluid to circulate at a high flow rate, i.e., once engaged and in communication with the hydraulic pump 43, of the same order of magnitude as the nominal flow rate of the hydraulic motor 41.

[0064] Therefore, the flow rate of the fluid discharged to retract the piston is equal to the flow rate to which the hydraulic motor 41 is exposed until its orifices 411, 412 suddenly communicate with the reservoir 44 and the hydraulic control valve 2 has switched from its working position P2 to its idle position P1. Thus, at this precise moment, the cam is still connected to the wheel 42 and the piston is in contact with the cam. However, this flow rate to which the hydraulic motor 41 is exposed can prove to be the maximum allowable flow rate of the hydraulic motor 41 at its maximum rotational speed. Similarly, the fluid flow rate for retracting the piston itself can be very high, typically 0.33 to 0.5 times the maximum acceptable flow rate of the hydraulic motor 41.

[0065] On the other hand, the flow rate for controlling the freewheel valve 1 (i.e., the flow rate of the fluid circulating from the outlet port 222 of the hydraulic control valve 2 towards the control chamber 14 of the freewheel valve 1 to switch the freewheel valve 1) is of the order of a few millimeters during a fraction of a second.

[0066] Thus, when the freewheel valve 1 is in the idle position P5, the ratio of the flow rate for controlling the freewheel valve 1 to the flow rate for supplying the hydraulic motor 41 from the boost line 400 to extend the piston (the hydraulic control valve 2 is in the operating position P2), or to the flow rate for discharging from the hydraulic motor 41 towards the reservoir 44 to retract the piston (the hydraulic control valve 2 is in the idle position P1) is between 80 and 120, and the preferred value is 100.

[0067] The hydraulic control valve 2 is sized to allow fluid to circulate through its slide member 23 at the same high flow rate, but without any significant load loss, so that the disengagement and engagement of the hydraulic motor 41 can occur quickly.

[0068] In an exemplary embodiment of the circuit, it is assumed that the secondary shaft includes two wheels 42, each wheel being coupled to a hydraulic motor 41, and the hydraulic motor 41 is configured to consume 100 liters at 45 revolutions per minute, which requires the hydraulic pump 43 to be configured to output 200 liters per minute. In addition, the fluid volume required to extend the piston of the hydraulic motor 41 is typically 150 cm 3 . In operation, the hydraulic motor 41 is configured to operate at a pressure between the boost pressure and 600 bar (i.e., 600 × 10 5 Pa), typically 300 bar (i.e., 300 × 10 5 Pa). In addition, the flow rate of the fluid required to control the control chamber 14 of the freewheel valve 1 is between 2 and 3 liters per minute, and when a pressure of at least 12 bar (i.e., 12 × 10 5 Pa) is set in the control chamber 14 of the freewheel valve 1, the freewheel valve 1 is configured to switch from its idle position P5 to its operating position P6. Finally, the flow rate of the fluid required to control the control chamber 24 of the hydraulic control valve 2 is 1 liter per minute, and when a pressure of at least 7 bar (i.e., 7 × 10 5 Pa) is set in the control chamber 24 of the hydraulic control valve 2, the hydraulic control valve 2 is configured to switch from its idle position P1 to its operating position P2. At the same time, the reversing electric valve 3 is sized to provide a limited control flow rate in the direction of the hydraulic control valve 2. Typically, at the boost pressure, the flow rate required for this control is approximately 2 liters per minute, preferably 1 liter per minute. In addition, the reversing electric valve 3 operates at a current of less than 2 A (typically 1.4 A) and an electric power of less than 20 W (typically 17 W). The combined use of the reversing electric valve 3 and the hydraulic control valve 2 thus makes it possible to limit the electric power required for the control circuit.

[0069] When engaging the hydraulic motor 41, the flow rate of the boost pump 45 is typically 50 liters per minute. The time taken to engage the piston is 0.5 seconds, i.e., the flow rate of the hydraulic motor 41 is approximately 20 liters per minute, the secondary shaft is 40 liters per minute, and the secondary shaft includes two wheels 42, each wheel being connected to the hydraulic motor 41. In addition, the time taken to switch the slider 13 of the freewheel valve 1 is 0.2 seconds.

[0070] When the hydraulic motor 41 is disengaged, the flow rate for discharging the cylinder of the hydraulic motor 41 is equal to the operating flow rate of the hydraulic motor 41 at its rotational speed, e.g., 100 liters per minute. At the rated speed of the hydraulic motor 41, the discharge time is 0.5 seconds.

[0071] This exemplary embodiment enables it to be observed that the flow rates required for the control valves 1, 2 are approximately 1 to 2 liters per minute, while the flow rate supplied to the hydraulic motor 41 is approximately 100 liters per minute. Accordingly, the hydraulic control valve 2 is dimensioned to cycle the fluid at a flow rate of 2 liters per minute during the expansion or retraction of the piston to control the freewheel valve 1 and to supply the hydraulic motor 41 at a flow rate of 50 to 100 liters per minute. Thus, the hydraulic motor 41 can be very quickly engaged and disengaged in less than 1 second. In this way, even when the vehicle is in motion and when the hydraulic motor 41 is driven by the wheels 42, the assistance of the wheels 42 can be engaged or disengaged, and in doing so, noise, torque vibrations, pressure peaks, and mechanical shock at the piston are minimized.

[0072] Therefore, using the hydraulically controlled reversing valve 2 to control the freewheel valve 1 enables high-flow-rate fluid to pass between the hydraulic motor 41 and the reservoir 44 or the boost line 400 respectively. Accordingly, the engagement and / or disengagement of the hydraulic motor 41 is simplified. Specifically, using a reversing electric valve instead and replacing Figure 1 the shown hydraulically controlled direction valve 2 to pass such a high-flow-rate fluid would necessitate increasing the size of the solenoid 34, which would result in an excessive circuit volume and cost. In contrast, since Figure 1 the shown reversing electric valve 3 only controls the hydraulic control valve 2 and no longer directly controls the freewheel valve 1, it can be smaller, especially since it only needs to allow low-flow-rate fluid to pass through, and thus has a smaller volume and consumes less energy.

[0073] Figure 1The circuit shown can be used only for the traction assistance of the vehicle. In this case, the main shaft is driven by the main motor of the vehicle by means of the main transmission, which may include a clutch, a gearbox and / or a driveline. In this case, the assembly formed by the power take-off, any clutch and the circuit constitutes a secondary transmission, and when the assistance is enabled, the torque supplied by the main motor can be transmitted to the non-driven wheels 42 via this secondary transmission. The secondary transmission is independent of the main transmission. In fact, the secondary shaft is not driven by the main transmission, but by the secondary transmission.

[0074] Alternatively, Figure 1 The circuit shown is also used to transfer mechanical power from the main motor to the drive wheels of the main shaft. Where applicable, each of the low-pressure line and the high-pressure line of the connecting circuit 40 is also connected in parallel with the hydraulic motor 41 to the orifices of at least one other hydraulic motor (not shown), and this connection to the other hydraulic motors is made upstream of the freewheel valve 1, i.e., directly at the orifices 431, 432 of the hydraulic pump 43. At the same time, the other hydraulic motors are coupled to the main shaft, which may be an axle shaft with a differential, with or without a reduction mechanism.

[0075] In any case, the flow direction within the connecting circuit 40 changes according to the desired direction of movement of the wheels (forward or backward), whether they are drive wheels or not.

Claims

1. A component of a hydraulic circuit for assisting in the towing of a vehicle, the component comprising: A freewheel valve (1); A hydraulic control valve (2), which is connected to the freewheel valve (1) and is configured to control the freewheel valve (1); And A reversing electric valve (3), which is connected to the hydraulic control valve (2) and is configured to control the hydraulic control valve (2).

2. The component according to claim 1, wherein The hydraulic control valve (2) comprises: A first inlet port (211), which is arranged to be connected to a reservoir (44) of the circuit; A second inlet port (212), which is arranged to be connected to a pressurization pipeline (400) of the circuit; and An outlet port (221), which is connected to a control chamber (14) of the freewheel valve (1) and a second inlet port (112).

3. The component according to claim 2, wherein, The hydraulic control valve (2) further comprises a sliding member (23) and a body, and the sliding member (23) can move within the body between the following positions: A first position (P1), in which the sliding member (23) allows fluid to circulate between the first inlet port (211) and the outlet port (221) of the hydraulic control valve (2), and prohibits fluid from circulating between the second inlet port (212) and the outlet port (221) of the hydraulic control valve (2); And A second position (P2), in which the sliding member (23) allows fluid to circulate between the second inlet port (212) and the outlet port (221) of the hydraulic control valve (2), and prohibits fluid from circulating between the first inlet port (211) and the outlet port (221) of the hydraulic control valve (2).

4. The component according to claim 3, wherein, The hydraulic control valve (2) further comprises: A control chamber (24), which is connected to the reversing electric valve (3) and is connected to the sliding member (23) of the hydraulic control valve (2), such that the pressure in the control chamber (24) exerts a first force on the sliding member (23) of the hydraulic control valve (2); and A return element (25), which is connected to the sliding member (23) and the body of the hydraulic control valve (2) so as to exert a second force on the sliding member (23) of the hydraulic control valve (2); Wherein, the movement of the sliding member (23) of the hydraulic control valve (2) between the first position (P1) and the second position (P2) of the hydraulic control valve (2) is controlled by the difference between the first force and the second force on the sliding member (23) of the hydraulic control valve (2).

5. The component according to any one of claims 1 to 4, wherein, The reversing electric valve (3) comprises: A first inlet port (311), which is arranged to be connected to a reservoir (44) of the circuit; A second inlet port (312), which is arranged to be connected to a pressurization pipeline (400) of the circuit; and An outlet port (321), which is connected to the control chamber (24) of the hydraulic control valve (2).

6. The component according to claim 5, wherein, The reversing electric valve (3) further comprises a sliding member (33) and a body, and the sliding member (33) can move within the body between the following positions: a first position (P3) in which the slide member (33) allows fluid to circulate between the first inlet port (311) and the outlet port (321) of the reversing electric valve (3) and prohibits fluid from circulating between the second inlet port (312) and the outlet port (321) of the reversing electric valve (3); and a second position (P4) in which the slide member (33) allows fluid to circulate between the second inlet port (312) and the outlet port (321) of the reversing electric valve (3) and prohibits fluid from circulating between the first inlet port (311) and the outlet port (321) of the reversing electric valve (3).

7. The component according to claim 6, wherein, The reversing electric valve (3) further comprises: a solenoid (34) configured to apply a first force on the slide member (33) of the reversing electric valve (3); and a return element (35) connected to the slide member (33) and the body of the reversing electric valve (3) so as to apply a second force on the second slide member (33) of the reversing electric valve (3); wherein the movement of the slide member (33) of the reversing electric valve (3) between the first position (P3) and the second position (P4) of the reversing electric valve (3) is controlled by the difference between the first force and the second force on the slide member (33) of the reversing electric valve (3).

8. The component according to any one of claims 1 to 7, wherein, The freewheel valve (1) comprises: a first inlet port (111) arranged to be connected to a first orifice of a hydraulic pump (43) of the circuit; a second inlet port (112) arranged to be alternately connected to a reservoir (44) of the circuit or a pressurizing line (400) of the circuit via the hydraulic control valve (2); a third inlet port (113) arranged to be connected to a second orifice of the pump (43); a first outlet port (121) arranged to be connected to a first orifice of a hydraulic motor (41) of the circuit; and a second outlet port (122) arranged to be connected to a second orifice of the motor (41).

9. The component according to claim 8, wherein The freewheel valve (1) further comprises a slide member (13) and a body, the slide member (13) being movable within the body between the following positions: a first position (P5) in which the slide member (13) allows fluid to circulate between the second inlet port (112) of the freewheel valve (1) and each of the first outlet port (121) and the second outlet port (122), and prohibits fluid from circulating between each of the first inlet port (111) and the third inlet (113) of the freewheel valve (1) and each of the first outlet port (121) and the second outlet port (122); and Second position (P6), in which the slider (13) allows fluid to circulate between the first inlet port (111) and the first outlet port (121) of the freewheel valve (1) and between the third inlet port (113) and the second outlet port (122), and prohibits fluid from circulating between the first inlet port (111) and the second outlet port (122) of the freewheel valve (1), between the second inlet port (112) and each of the first outlet port (121) and the second outlet port (122), and between the third inlet port (113) and the first outlet port (121).

10. The component according to claim 9, wherein, The freewheel valve (1) further comprises: A control chamber (14) which is connected to the hydraulic control valve (2) and to the slider (13) of the freewheel valve (1), such that the pressure in the control chamber (14) exerts a first force on the slider (13) of the freewheel valve (1); and A return element (15) which is connected to the slider (13) of the freewheel valve (1) and to the third body, so as to exert a second force on the slider (13) of the freewheel valve (1); Wherein the movement of the slider (13) of the freewheel valve (1) between the first position (P5) and the second position (P6) of the freewheel valve (1) is controlled by the difference between the first force and the second force on the slider (13) of the freewheel valve (1).

11. The assembly according to any one of claims 1 to 10, wherein: The freewheel valve (1) comprises: A first inlet port (111) which is arranged to be connected to a first orifice of the hydraulic pump (43) of the circuit; A second inlet port (112) which is arranged to be alternately connected to the reservoir (44) of the circuit or the boost line (400) of the circuit via the hydraulic control valve (2); A third inlet port (113) which is arranged to be connected to a second orifice of the pump (43); A first outlet port (121) which is arranged to be connected to a first orifice of the hydraulic motor (41) of the circuit; A second outlet port (122) which is arranged to be connected to a second orifice of the motor (41); A slider (13) and a body, the slider (13) being movable within the body between the following positions: First position (P5), in which the slider (13) allows fluid to circulate between the second inlet port (112) of the freewheel valve (1) and each of the first outlet port (121) and the second outlet port (122), and prohibits fluid from circulating between each of the first inlet port (111) and the third inlet port (113) of the freewheel valve (1) and each of the first outlet (121) and the second outlet (122); and A second position (P6) in which the slide member (13) allows fluid to circulate between the first inlet port (111) and the first outlet port (121) of the freewheel valve (1) and between the third inlet port (113) and the second outlet port (122), and prohibits fluid from circulating between the first inlet port (111) and the second outlet port (122) of the freewheel valve (1), between the second inlet port (112) and each of the first outlet port (121) and the second outlet port (122), and between the third inlet port (113) and the first outlet port (121); A control chamber (14) which is connected to the hydraulic control valve (2) and to the slide member (13) of the freewheel valve (1) such that the pressure in the control chamber (14) exerts a first force on the slide member (13) of the freewheel valve (1); and A return element (15) which is connected to the slide member (13) of the freewheel valve (1) and to the third body so as to exert a second force on the slide member (13) of the freewheel valve (1); wherein the movement of the slide member (13) of the freewheel valve (1) between the first position (P5) and the second position (P6) of the freewheel valve (1) is controlled by the difference between the first force and the second force on the slide member (13) of the freewheel valve (1); The hydraulic control valve (2) comprises: A first inlet port (211) which is arranged to be connected to the reservoir (44) of the circuit; A second inlet port (212) which is arranged to be connected to the pressurization line (400) of the circuit; An outlet port (221) which is connected to the control chamber (14) of the freewheel valve (1) and to the second inlet port (112); and A slide member (23) and a body, the slide member (23) being movable within the body between the following positions: A first position (P1) in which the slide member (23) allows fluid to circulate between the first inlet port (211) and the outlet port (221) of the hydraulic control valve (2) and prohibits fluid from circulating between the second inlet port (212) and the outlet port (221) of the hydraulic control valve (2); and A second position (P2) in which the slide member (23) allows fluid to circulate between the second inlet port (212) and the outlet port (221) of the hydraulic control valve (2) and prohibits fluid from circulating between the first inlet port (211) and the outlet port (221) of the hydraulic control valve (2), and Wherein, in a first position (P5) of a sliding member (13) of the overrunning valve (1) and a second position (P2) of a sliding member (23) of the hydraulic control valve (2), the overrunning valve (1) and the hydraulic control valve (2) are configured to connect the boost line (400) to a control chamber (14) of the overrunning valve (1) and to the motor (41).

12. The assembly according to any one of claims 1 to 11, wherein: The overrunning valve (1) comprises: A first inlet port (111) which is arranged to be connected to a first orifice of a hydraulic pump (43) of the circuit; A second inlet port (112) which is arranged to be alternately connected to a reservoir (44) of the circuit or to the boost line (400) of the circuit via the hydraulic control valve (2); A third inlet port (113) which is arranged to be connected to a second orifice of the pump (43); A first outlet port (121) which is arranged to be connected to a first orifice of a hydraulic motor (41) of the circuit; A second outlet port (122) which is arranged to be connected to a second orifice of the motor (41); A sliding member (13) and a body, the sliding member (13) being movable within the body between the following positions: A first position (P5) in which the sliding member (13) allows fluid to circulate between the second inlet port (112) of the overrunning valve (1) and each of the first outlet port (121) and the second outlet port (122), and prohibits fluid from circulating between each of the first inlet port (111) and the third inlet port (113) of the overrunning valve (1) and each of the first outlet port (121) and the second outlet port (122); and A second position (P6) in which the sliding member (13) allows fluid to circulate between the first inlet port (111) and the first outlet port (121) of the overrunning valve (1) and between the third inlet port (113) and the second outlet port (122), and prohibits fluid from circulating between the first inlet port (111) and the second outlet port (122) of the overrunning valve (1), between the second inlet port (112) and each of the first outlet port (121) and the second outlet port (122), and between the third inlet port (113) and the first outlet port (121); A control chamber (14) which is connected to the hydraulic control valve (2) and to the sliding member (13) of the overrunning valve (1) such that the pressure within the control chamber (14) exerts a first force on the sliding member (13) of the overrunning valve (1); and A return element (15) which is connected to the sliding member (13) of the overrunning valve (1) and a third body so as to exert a second force on the sliding member (13) of the overrunning valve (1); Wherein, the movement of the slider (13) of the overrunning valve (1) between the first position (P5) and the second position (P6) of the overrunning valve (1) is controlled by the difference between a first force and a second force on the slider (13) of the overrunning valve (1); The hydraulic control valve (2) includes: A first inlet port (211) which is arranged to be connected to the reservoir (44) of the circuit; A second inlet port (212) which is arranged to be connected to the pressurization pipeline (400) of the circuit; and An outlet port (221) which is connected to the control chamber (14) of the overrunning valve (1) and the second inlet port (112); and Wherein, the assembly further includes a pipeline connecting the outlet port (221) of the control valve (2) to the control chamber (14) of the overrunning valve (1), and the pipeline includes a nozzle (48) arranged to adjust the flow rate from the pressurization pipeline (400).

13. The component according to claim 12, wherein, The hydraulic control valve (2) further includes: A slider (23) and a body, the slider (23) being capable of moving within the body between the following positions: A first position (P1), in which the slider (23) allows fluid to circulate between the first inlet port (211) and the outlet port (221) of the hydraulic control valve (2), and prohibits fluid from circulating between the second inlet port (212) and the outlet port (221) of the hydraulic control valve (2); and A second position (P2), in which the slider (23) allows fluid to circulate between the second inlet port (212) and the outlet port (221) of the hydraulic control valve (2), and prohibits fluid from circulating between the first inlet port (211) and the outlet port (221) of the hydraulic control valve (2).

14. The component according to any one of claims 11 to 13, wherein, The hydraulic control valve (2) further includes: A control chamber (24) which is connected to the reversing solenoid valve (3) and to the slider (23) of the hydraulic control valve (2), such that the pressure in the control chamber (24) exerts a first force on the slider (23) of the hydraulic control valve (2); and A return element (25) which is connected to the slider (23) and the body of the hydraulic control valve (2) so as to exert a second force on the slider (23) of the hydraulic control valve (2); Wherein, the movement of the slider (23) of the hydraulic control valve (2) between the first position (P1) and the second position (P2) of the hydraulic control valve (2) is controlled by the difference between a first force and a second force on the slider (23) of the hydraulic control valve (2).

15. The component according to any one of claims 11 to 14, wherein, The reversing solenoid valve (3) includes: A first inlet port (311) which is arranged to be connected to the reservoir (44) of the circuit; A second inlet port (312) which is arranged to be connected to the pressurization pipeline (400) of the circuit; and An outlet port (321) which is connected to the control chamber (24) of the hydraulic control valve (2).

16. The component according to claim 15, wherein, The reversing electric valve (3) further includes a sliding member (33) and a main body, and the sliding member (33) is capable of moving within the main body between the following positions: A first position (P3), in which the sliding member (33) allows fluid to circulate between the first inlet port (311) and the outlet port (321) of the reversing electric valve (3), and prohibits fluid from circulating between the second inlet port (312) and the outlet port (321) of the reversing electric valve (3); and A second position (P4), in which the sliding member (33) allows fluid to circulate between the second inlet port (312) and the outlet port (321) of the reversing electric valve (3), and prohibits fluid from circulating between the first inlet port (311) and the outlet port (321) of the reversing electric valve (3).

17. The component according to claim 16, wherein, The reversing electric valve (3) further includes: A solenoid (34), which is configured to apply a first force on the sliding member (33) of the reversing electric valve (3); and A return element (35), which is connected to the sliding member (33) and the main body of the reversing electric valve (3) so as to apply a second force on the second sliding member (33) of the reversing electric valve (3); wherein, the movement of the sliding member (33) of the reversing electric valve (3) between the first position (P3) and the second position (P4) of the reversing electric valve (3) is controlled by the difference between the first force and the second force on the sliding member (33) of the reversing electric valve (3).

18. A hydraulic circuit for assisting in the traction of a vehicle, the circuit comprising: A hydraulic motor (41), which is arranged to be coupled to a wheel (42) of the vehicle; A hydraulic pump (43); and The assembly according to any one of claims 1 to 17; wherein, the freewheel valve (1) is configured to control the fluid circulation between the pump (43) and the motor (41).

19. The circuit according to claim 18, wherein The pump (43) includes a first orifice (431) and a second orifice (432), and the hydraulic motor (41) includes a first orifice (411) and a second orifice (412), and the circuit further includes: A communication circuit (40), which connects the first orifice (431) of the pump (43) to the first orifice (411) of the motor (41), and connects the second orifice (432) of the pump (43) to the second orifice (412) of the motor (41), and the communication circuit (40) includes the freewheel valve (1); A reservoir (44); A booster pump (45), which includes an inlet orifice and a discharge orifice connected to the reservoir (44); and A booster pipeline (400), which is connected to the discharge orifice of the booster pump (45) and the communication circuit (40); wherein, the freewheel valve (1) and the hydraulic control valve (2) are configured to control the fluid circulation between on the one hand the motor (41) and on the other hand the pump (43), the booster pipeline (400) and / or the reservoir (44).

20. The circuit according to claim 19, wherein, The hydraulic control valve (2) is configured to allow fluid to circulate between the motor (41) and the boost line (400) and / or the reservoir (44) at a flow rate of 50 to 100 liters per minute.

21. The circuit according to any one of claims 18 to 20, wherein, The engagement time and / or disengagement time of the motor (41) is less than 1 second, preferably less than 0.5 second.

22. The circuit according to any one of claims 18 to 21, wherein, The reversing electric valve (3) is configured to consume less than 20 W of electric power to control the hydraulic control valve (2).

23. A vehicle, comprising: A main shaft for supporting at least one drive wheel of the vehicle; A countershaft separated from the main shaft; A wheel (42) mounted on the countershaft; And A circuit according to any one of claims 18 to 22, wherein the motor (41) is coupled to the wheel (42).

24. A method for controlling a vehicle, the vehicle comprising a main shaft for supporting at least one drive wheel of the vehicle, a countershaft separated from the main shaft, and a wheel (42) mounted on the countershaft, the method comprising: A reversing electric valve (3) controls a hydraulic control valve (2); and The hydraulic control valve (2) controls the freewheel valve (1) of the hydraulic motor (41) of the vehicle coupled to the wheel (42); Wherein, the enabling of the reversing electric valve (3) causes the enabling of the hydraulic control valve (2), so that the freewheel valve (1) can first set fluid circulation between the motor (41) of the vehicle and the boost line (400), and then set fluid circulation between the hydraulic pump (43) and the motor (41) of the vehicle; and Wherein, the disabling of the reversing electric valve (3) causes the disabling of the hydraulic control valve (2), thereby disabling the freewheel valve (1) to isolate the pump (43) from the motor (41), and connecting the motor (41) of the vehicle to the reservoir (44) through the hydraulic control valve (2).

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