Triple-piston motor vehicle anti-roll device

Abstract

The invention provides an anti-roll device (30) for a motor vehicle. A hydraulic cylinder (32) comprises: an actuating rod (36), a first chamber (40), a second chamber (42), a third chamber (44). The hydraulic circuit (34) comprises: a hydraulic accumulator (46) with hydraulic fluid, a first branch (48) between the first chamber and the hydraulic accumulator, a second branch (50) between the second chamber and the hydraulic accumulator, two valves (52), two non-return valves capable of blocking a flow of hydraulic fluid from the hydraulic accumulator to the cylinder.The hydraulic cylinder comprises a first piston (56) movable relative to the actuating rod and delimiting the first chamber, a second piston (58) movable relative to the actuating rod and delimiting the second chamber, means (60) for driving the actuating rod by the first piston towards the second chamber, and by the second piston towards the first chamber. Figure to be published with the abstract: Figure 2.

Description

Title of the invention: Triple-piston motor vehicle anti-roll device

[0001] The invention relates to the control of the attitude of a motor vehicle. The invention relates to the control of the roll of a motor vehicle by means of an anti-roll bar and a jack control device. The invention proposes an anti-roll device with a jack for a motor vehicle. The invention also relates to a motor vehicle.

[0002] A motor vehicle is commonly equipped with an anti-roll system. As is known to those skilled in the art, such an anti-roll system; also called an anti-roll system or stabilization system; is equipment comprising a bar whose opposite ends are coupled respectively to right and left wheels of a train of a motor vehicle via two connecting rods. Such a system equips the front axle, and optionally the rear axle.

[0003] This system is mainly used when the motor vehicle is traveling on a bend or on a road that is degraded asymmetrically relative to its longitudinal axis. In a bend or curve, the bar is stressed in torsion and bending to maintain the attitude as much as possible. Therefore, the higher its stiffness, the more effective it is. In the presence of degradation of the road surface, the bar partially transmits the irregularity of the road surface experienced by one of the wheels of a train to the other wheel of the same train by a phenomenon of "roll return". Therefore, the higher its stiffness, the more it induces a degradation of comfort.

[0004] By associating a hydraulic cylinder with each connecting rod, it is possible to mitigate the loss of comfort. In this case, each hydraulic cylinder includes a solenoid valve, non-return valves and a hydraulic fluid accumulator to compensate for volume variations induced by the movements of the piston of the hydraulic cylinder. However, such a solution increases the cost, the mass and creates a need for electrical energy for the control of each solenoid valve. In addition, it is exposed to a risk of breakdown. The algorithms for generating the solenoid valve commands are complex.

[0005] Document FR3101809B1 presents an anti-roll device for a motor vehicle comprising a torsion bar and two lateral connecting rods, at least one of which comprises a cylinder and a sliding piston delimiting in the cylinder two chambers connected to each other by a hydraulic circuit comprising a valve adapted to selectively open and close the hydraulic circuit. The two chambers contain a constant total volume of liquid. The valve is controlled by an electronic central unit. The two chambers respectively contain two compressible stop members limiting a stroke of the piston. The anti-roll device has a sliding separator piston 8a with sealing in the cylinder. The piston and its rod are free from contact with the sliding separator piston.

[0006] The hydraulic circuit does not make it possible to ensure that the corresponding hydraulic cylinder is in the central position; a position in which it does not provide any force; when it is placed in a blocked state. The blocked state prohibits a variation in the length of the cylinder; and therefore a correction of the attitude. Verification that the piston reaches the neutral position before locking requires sensors, which also consume energy.

[0007] Document FR2670716B1 presents a safety device mounted on an active anti-roll hydraulic cylinder for a motor vehicle axle in which an anti-roll torsion bar which is articulated to the body has one of its ends connected to one of the suspension arms by a rigid connecting rod and at its other end connected to the other suspension arm by a hydraulic cylinder controlled in position or force by an oil pressure generating device. The supply of the upper and lower chambers of the hydraulic cylinder is ensured by two two-position hydraulic distributors which, in the event of failure of the active control system, automatically and without external energy input put the two chambers of the hydraulic cylinder in communication with a safety circuit which blocks the cylinder in its middle position.

[0008] In normal operation, the cylinder is powered through the distributors by an energy source such as an electrohydraulic member. However, this electrohydraulic member involves a consumption of primary energy. Furthermore, in the event of a failure, the solenoid valves close. When it is in the lower part of the cylinder during closing, the piston only returns to the middle position following a "compression" stress. However, such a compression stress generally only occurs after a period of time during which safety is degraded.

[0009] The invention aims to address at least one of the problems or drawbacks encountered in the prior art. In particular, the invention aims to facilitate a return to neutral position of an anti-roll device of a motor vehicle. The invention also aims to enable an autonomous return to neutral position of an anti-roll device cylinder of a motor vehicle. The invention also aims to optimize the safety, speed of response, mass, and compactness of an anti-roll device cylinder of a motor vehicle.

[0010] According to a first aspect, the invention proposes an anti-roll device intended to be connected to an anti-roll bar of a motor vehicle, the anti-roll device comprising a hydraulic cylinder; a hydraulic circuit; the hydraulic cylinder comprising: an actuating rod, a cylinder with a first chamber, a second chamber opposite the first chamber; the hydraulic circuit comprising: a hydraulic accumulator intended to receive a hydraulic liquid under pressure, a first branch between the first chamber and the hydraulic accumulator, a second branch between the second chamber and the hydraulic accumulator, at least one valve, at least one non-return valve capable of blocking a flow of hydraulic liquid from the hydraulic accumulator to the cylinder; remarkable in that the hydraulic cylinder comprises a first piston movable relative to the actuating rod and delimiting the first chamber, a second piston movable relative to the actuating rod and delimiting the second chamber; the cylinder further having a third chamber between the first piston and the second piston; the hydraulic cylinder comprises means for driving the actuating rod by the first piston towards the second chamber, and by the second piston towards the first chamber in order to move the actuating rod towards a neutral position.

[0011] Thanks to the two pistons and the hydraulic accumulator, the invention allows a return to neutral position. In fact, the hydraulic accumulator maintains the pressure necessary to return to equilibrium after movement of each piston. This behavior is obtained passively since no external energy source, no sensor, is necessary to obtain a result. Safety is optimized.

[0012] Preferably, the drive means comprise a first axial stop capable of driving the first piston towards the first chamber, and a second axial stop capable of driving the second piston towards the second chamber.

[0013] Preferably, the cylinder comprises a first seat capable of holding the first piston at a first end of the first chamber, and a second seat capable of holding the second piston at a second end of the second chamber.

[0014] Preferably, the at least one valve comprises a first valve in the first branch, and a second valve in the second branch.

[0015] Preferably, the at least one non-return valve comprises a first non-return valve associated with the first branch, and a second non-return valve associated with the second branch.

[0016] Preferably, the first branch comprises a first bypass receiving the first non-return valve, the second branch comprises a second bypass receiving the second non-return valve.

[0017] Preferably, the drive means are arranged in the third chamber.

[0018] Preferably, the drive means comprise a cylindrical body.

[0019] Preferably, the actuating rod passes through the first piston.

[0020] Preferably, the cylinder comprises an internal surface, the first piston comprising an external seal cooperating with said internal surface, and an internal seal cooperating with the actuating rod.

[0021] Preferably, the second piston comprises a drive surface in the extension of the actuating rod.

[0022] Preferably, the second piston comprises a sealed plate forming a seal between the second chamber and the third chamber.

[0023] Preferably, the first piston comprises a first outside diameter, the second piston comprises a second outside diameter, the drive means comprise a third outside diameter smaller than the first outside diameter and the second outside diameter.

[0024] Preferably, the actuating rod is able to move relative to the first piston towards the second chamber, and to move relative to the second piston towards the first chamber.

[0025] Preferably, the valve is movable between an open configuration and a closed configuration capable of cutting off a flow of hydraulic liquid in the first branch and / or in the second branch.

[0026] Preferably, the third chamber is between the first chamber and the second chamber.

[0027] Preferably, the third chamber is delimited by the first piston and the second piston.

[0028] Preferably, the hydraulic accumulator is intended to reinject the hydraulic fluid under pressure.

[0029] Preferably, the hydraulic accumulator comprises a closed enclosure with a hydraulic fluid pressurization module.

[0030] Preferably, the at least one valve comprises a two-way valve.

[0031] Preferably, the at least one valve comprises a solenoid valve.

[0032] Preferably, the hydraulic circuit has a central branch connecting the hydraulic accumulator to each valve and to each non-return valve.

[0033] According to another aspect, the invention proposes an anti-roll device intended to be connected to an anti-roll bar of a motor vehicle, the anti-roll device comprising a hydraulic cylinder; a hydraulic circuit; the hydraulic cylinder comprising: an actuating rod, a cylinder with a first chamber, a second chamber; the hydraulic circuit comprising: a hydraulic accumulator intended to receive a hydraulic fluid, a first branch between the first chamber and the hydraulic accumulator, a second branch between the second chamber and the hydraulic accumulator, at least one valve, at least one non-return valve capable of blocking a flow of hydraulic fluid from the hydraulic accumulator to the cylinder;remarkable in that the hydraulic cylinder comprises a first piston movable relative to the actuating rod and delimiting the first chamber, a second piston movable relative to the actuating rod and delimiting the second chamber; the cylinder; further having a third chamber between the first piston and the second piston; the actuating rod comprising means for driving the first piston towards the first chamber, and the second piston towards the second chamber, so as to transfer pressurized hydraulic fluid from the cylinder to the hydraulic accumulator. Such an anti-roll device allows passive and safe operation.

[0034] According to another aspect, the invention provides a motor vehicle comprising an anti-roll system with an anti-roll bar and an anti-roll device coupled to the anti-roll bar, remarkable in that the anti-roll device is in accordance with the invention.

[0035] Preferably, the anti-roll bar comprises a first side and a second side transversely opposite the first side, the hydraulic cylinder being fixed to the first side, and the anti-roll system further comprises a rigid connecting rod fixed to the second side.

[0036] Each characteristic introduced by the expression “preferably” given in relation to one of the aspects of the invention applies to all the other aspects of the invention.

[0037] The invention will be well understood and other aspects and advantages will appear clearly on reading the description which follows, given with reference to the figures appended and listed below.

[0038] [Fig.l] is a front view of a motor vehicle according to the invention.

[0039] [Fig.2] represents an anti-roll device for a motor vehicle according to a first embodiment of the invention.

[0040] [Fig. 3] represents the anti-roll device of a motor vehicle according to the first embodiment of the invention.

[0041] [Fig.4] illustrates an actuation movement of the motor vehicle anti-roll device according to the first embodiment of the invention.

[0042] [Fig. 5] illustrates the return to neutral position of the anti-roll device of a motor vehicle according to the first embodiment of the invention.

[0043] [Fig.6] represents an anti-roll device for a motor vehicle according to a second embodiment of the invention.

[0044] [Fig.7] represents an anti-roll device for a motor vehicle according to a third embodiment of the invention.

[0045] In the following description, the term "comprise" is synonymous with "include" and is not limiting in that it allows the presence of other elements in the motor vehicle or the anti-roll device to which it relates. It is understood that the term "comprise" includes the terms "consist of".

[0046] In the present description, the term “longitudinal”, the term “longitudinally”, the term “transverse”, and the term “transversely” are used according to the re vehicle's direction of travel, in the mounting configuration. The term "longitudinal" refers to the vehicle's primary direction of travel. The term "transverse" refers to a direction perpendicular to the vehicle's primary direction of travel. The term "front" refers to the vehicle's primary direction of travel. The term "rear" refers to the opposite of the front of the vehicle.

[0047] In the present description, the term "axial" and the term "axially" are used according to the sliding direction of the actuating rod of the hydraulic cylinder.

[0048] The X axis represents the longitudinal direction, the Y axis represents the transverse direction, and the Z axis represents the vertical direction of the motor vehicle. These three axes define a direct trihedron.

[0049] In this description, the technical characteristics are defined in the mounting configuration of the anti-roll device, unless explicitly mentioned otherwise.

[0050] Throughout the description, the different figures use the same reference signs to designate identical or similar entities.

[0051] [Fig.l] represents a motor vehicle 10 according to the invention. The motor vehicle 10 comprises energy storage means and at least one motor (not shown) adapted to drive said motor vehicle 10.

[0052] The motor vehicle 10 comprises a structure 12. The structure 12 forms an outer body, or a main frame of the motor vehicle. The structure 12 delimits different compartments of the motor vehicle 10. The structure 12 forms a mounting support for the powertrain, the suspension systems 14, the steering system 16, the anti-roll system 18. The anti-roll system 18 and the steering system 16 are coupled to the suspension systems 14.

[0053] Each suspension system 14 comprises at least one suspension arm 20, also called a suspension wishbone. The suspension arm 20 is pivotally mounted to the structure 12. A suspension spring and a shock absorber are commonly provided in each suspension system 14.

[0054] The anti-roll system 18 comprises an anti-roll bar 22, also called a torsion bar. The anti-roll bar 22 comprises a central section extending transversely and connected by pivot links 24 to the structure 12. The anti-roll bar 22 comprises lateral sections 26 inclined relative to the central section, and extending longitudinally. Their free ends are coupled to the suspension arms 20. On one side, the lateral section 26 is connected to the suspension arm 20 via a rigid connecting rod 28. On the other side, the lateral section 26 is connected to the suspension arm 20 via an anti-roll device 30. The rigid connecting rod 28 is understood to be essentially inextensible.

[0055] Thanks to the anti-roll bar 22, and in particular the orientations of the lateral sections 26, the movements of one of the wheels are transmitted to the other wheel of the corresponding axle. The rolling of the motor vehicle causes elastic torsion of the anti-roll bar 22; which is attenuated by the extension and compression movements of the anti-roll device 30.

[0056] The motor vehicle may, for example, be a private motor vehicle or a utility motor vehicle.

[0057] In the present illustration, the anti-roll system is associated with the front axle. However, the rear axle may also comprise such an anti-roll system.

[0058] [Fig. 2] shows an anti-roll device 30 for a motor vehicle anti-roll system. The motor vehicle corresponds to that shown in relation to [Fig. 1]. The anti-roll device 30 is shown in the active configuration, or open configuration. It is free to extend and retract.

[0059] The anti-roll device 30 comprises a hydraulic cylinder 32 and a hydraulic circuit 34 hydraulically connected to the hydraulic cylinder 32. The hydraulic cylinder 32 comprises: an actuating rod 36, a cylinder 38 with a first chamber 40, a second chamber 42, a third chamber 44. The cylinder 38 is formed by a tubular body. It may be an inner cylinder. It forms an internal space. The tubular body as actuating rod 36 comprises fixing ball joints at their ends.

[0060] The third chamber 44 is axially between the first chamber 40 and the second chamber 42. The first chamber 40 and the second chamber 42 are filled with hydraulic fluid; for example, oil. The third chamber 44 may contain another fluid, for example, gas, or another liquid. The third chamber 44 is delimited by the first piston and the second piston.

[0061] The hydraulic circuit 34 comprises: a hydraulic accumulator 46 intended to receive a hydraulic fluid from the cylinder 38, a first branch 48 connecting the first chamber 40 to the hydraulic accumulator 46, a second branch 50 connecting the second chamber to the accumulator, at least one valve 52, at least one non-return valve 54 capable of blocking a flow of hydraulic fluid from the hydraulic accumulator 46 to the cylinder 38. Each non-return valve 54 comprises a shutter, such as a ball, held by a spring on an associated seat. Thus, circulation is only possible in one direction of flow.

[0062] The hydraulic accumulator 46 is a pressure and liquid accumulator. The hydraulic accumulator 46 forms a gas pressure reservoir. The hydraulic accumulator 46 is intended to receive, then reinject, the pressurized hydraulic fluid from and to the first chamber 40 and the second chamber 42. The hydraulic accumulator 46 comprises a closed enclosure with a pressurization module (not shown) of the hydraulic fluid. The pressurization module may include a gas pocket.

[0063] The hydraulic cylinder 32 further comprises a first piston 56 movable relative to the actuating rod 36 and delimiting the first chamber 40, a second piston 58 movable relative to the actuating rod 36 and delimiting the second chamber 42. The third chamber 44 is between the first piston 56 and the second piston 58 which separate it from the first chamber 40 and the second chamber 42. The two pistons partition the cylinder 38 into three chambers.

[0064] The actuating rod 36, or more generally the hydraulic cylinder 32, comprises drive means 60. The drive means 60 are configured to drive the first piston 56 towards the first chamber 40, and to drive the second piston 58 towards the second chamber 42. In response to these drive movements, the pistons push the fluid out of the chambers towards the hydraulic accumulator 46 so as to transfer pressurized hydraulic fluid from the cylinder 38 to the hydraulic accumulator 46 via the branches.

[0065] The drive means 60 are configured to drive the first piston 56 in a first direction inside the cylinder 38, and to drive the second piston 58 in a second direction opposite to the first direction inside the cylinder 38. The drive means 60 are arranged in the third chamber 44. They are between the pistons.

[0066] Then, the hydraulic accumulator 46 returns the pressurized hydraulic fluid to the original chamber. In doing so, the hydraulic fluid pushes the corresponding piston and allows the actuating rod 36 to return to its neutral position; or position of equilibrium of the pressures on the pistons.

[0067] Therefore, in the event of the actuating rod 36 being shifted, and therefore one of the pistons being shifted, the drive means 60 are configured so as to drive the actuating rod 36 by the first piston 56 towards the second chamber 42, and to drive the actuating rod 36 by the second piston 58 towards the first chamber 40. The drive means 60 are reciprocal drive means.

[0068] The actuating rod 36 is able to move relative to the first piston 56 toward the second chamber 42 when it pushes the second piston 58, and to move relative to the second piston 56 toward the first chamber 40 when it pushes the first piston. Generally, the drive means 60 allow a movement of the actuating rod 36 relative to the first piston 56 toward the second piston 58, and allow a movement of the actuating rod 36 relative to the second piston 58 toward the first piston 56.

[0069] The drive means 60 comprise a central body between the first piston 56 and the second piston 58. The central body forms an enlargement on the rod drive. The central body is a cylindrical body 62.

[0070] The actuating rod 36 passes axially through the first piston 56, and is preferably flush with the second piston 58. The cylinder 38 comprises an internal surface 64. The first piston 56 comprises an external seal 66 cooperating with said internal surface 64, and an internal seal 68 cooperating with the actuating rod 36. The seals are O-rings.

[0071] According to one embodiment, the drive means 60 comprise a first axial stop 70 capable of axially driving the first piston 56 towards the first chamber 40, and a second axial stop 72 capable of axially driving the second piston 58 towards the second chamber 42. The first axial stop 70 is capable of driving the actuating rod 36 via the first piston 56 towards the second chamber 42. The second axial stop 72 is capable of driving the actuating rod 36 via the second piston 58 towards the first chamber 40.

[0072] The cylinder 38 comprises a first seat 74 capable of holding the first piston 56 at a first end of the first chamber 40, and a second seat 76 capable of holding the second piston 58 at one end; called the second end; of the second chamber 42. The seats are axial retainers. The first seat 74 and the second seat 76 are in the third chamber 44. Their spacing is equal to the axial length of the drive means 60.

[0073] The at least one valve 52 is movable between an open configuration and a closed configuration in which it cuts off a flow of hydraulic liquid in the first branch 48 and / or in the second branch 50. The at least one valve 52 comprises a two-way valve; for example a two-way solenoid valve.

[0074] The at least one valve 52 comprises a first valve 78 arranged on the first branch 48, and a second valve 80 arranged on the second branch 50. The hydraulic circuit 34 has a central branch 82 connecting the hydraulic accumulator 46 to each valve 52 and to each non-return valve 54.

[0075] The at least one non-return valve 54 comprises a first non-return valve 84 associated with the first branch 48, and a second non-return valve 86 associated with the second branch 50. The first branch 48 has a first bypass 88 receiving the first non-return valve 84, the second branch 50 has a second bypass 90 receiving the second non-return valve 86. The bypasses are generally designated by the English term “bypass”. They allow parallel mounting of a valve and a non-return valve in the same branch.

[0076] The second piston 58 comprises a drive surface 92 in the axial extension of the actuating rod 36. The drive surface 92 is towards the first piston 56. The second piston 58 comprises or forms a sealing plate sealingly separating the second chamber 42 from the third chamber 44.

[0077] [Fig. 3] shows an anti-roll device 30 for a motor vehicle anti-roll system. The motor vehicle corresponds to that shown in relation to one of Figures 1 to 2. The anti-roll device 30 is shown in the locked configuration, or closed configuration.

[0078] The at least one valve 52 is in the closed position and cuts off the flow of hydraulic fluid from the cylinder 38 to the hydraulic accumulator 46. The actuating rod 36 is in the neutral position. It can no longer move. It is held in position by the first piston 56 and the second piston 58 which are themselves against the first seat 74 and the second seat 76.

[0079] The first piston 56 comprises a first outer diameter 94, the second piston 58 comprises a second outer diameter 96 which correspond to the inner diameter of the cylinder 38. The drive means 60 comprise a third outer diameter 98 smaller than the first outer diameter 94 and / or the second outer diameter 96. This aspect allows axial flow along the drive means 60 when the actuating rod 36 is actuated. This also facilitates the passage between the first seat 74 and the second seat 76.

[0080] [Fig. 4] shows an anti-roll device 30 for a motor vehicle anti-roll system. The motor vehicle corresponds to that shown in relation to one of Figures 1 to 3. The anti-roll device 30 is in an open configuration.

[0081] The anti-roll device 30 is actuated, for example by retracting the actuating rod 36 into the cylinder 38, thus in compression. Thanks to the drive means 60, the actuating rod 36 drives the second piston 58 into the second chamber 42; and moves it away from the first chamber 40. The third chamber 44 lengthens. The second piston 58 leaves the second seat 76.

[0082] In response to this movement, hydraulic fluid contained in the second chamber 42 is transferred into the hydraulic accumulator 46, and forms an exhaust flow leaving the hydraulic cylinder 32 towards the hydraulic circuit 34. A flow passes through the second branch 50 via the second valve 80. It bypasses the second non-return valve 86. The hydraulic accumulator 46 accumulates the hydraulic fluid and maintains the pressure thereof. It remains under pressure. It stores hydraulic energy.

[0083] The present figure illustrates a movement of the actuating rod 36 in one direction. The phenomena occurring in the opposite direction can be deduced by symmetry. In this opposite direction, the actuating rod 36 pushes the first piston 56 towards the first chamber 40 by means of the drive means 60, while the second piston 58 remains against the second seat 76.

[0084] [Fig.5] shows an anti-roll device 30 for a vehicle anti-roll system at car. The motor vehicle corresponds to that shown in relation to one of figures 1 to 4. The anti-roll device 30 is in the closed configuration, the actuating rod 36 remains mobile. The anti-roll device 30 follows a relaxation movement.

[0085] Now, the at least one valve 52, in this case the second valve 80, is closed. Thanks to its internal pressure, the hydraulic accumulator 46 returns the hydraulic fluid to the second chamber 42. It restores the hydraulic energy. To do this, the flow takes the second branch 50, and more precisely the second non-return valve 86 present on the second bypass 90. The flow of hydraulic fluid now bypasses the second valve 80 which is now closed.

[0086] Thanks to the pressure of the hydraulic liquid in the second chamber 42 exerted on the second piston 58, a thrust force is transmitted to the actuating rod 36 via the drive means 60. The actuating rod 36 slides in the first piston 56, and gradually comes out of the cylinder 38.

[0087] Due to the valve closures and the orientation of each check valve, the actuating rod 36 can no longer extend further. Its movement is one-way until its neutral position.

[0088] [Fig.6] shows an anti-roll device 30 for a motor vehicle anti-roll system according to a second embodiment. The motor vehicle corresponds to that shown in relation to [Fig.1].

[0089] The anti-roll device 30 is substantially similar to that of the first embodiment. It differs, however, in that the same non-return valve 54 is shared for the first chamber 40 and the second chamber 42. The non-return valve 54 communicates with the first branch 48 and the second branch 50.

[0090] The drive means 60 also differ. The drive means 60 are in the first chamber 40 and the second chamber 42. The drive means 60 comprise a flexible link. For example, they comprise cables 100. The cables 100 connect the actuating rod to the first piston 56 and to the second piston 58.

[0091] When it is under tension, each cable 100 makes it possible to pull the associated piston in a first direction via the actuating rod 36. Thanks to its flexibility, each cable 100 allows movement in a second direction; opposite to the first direction; of the actuating rod 36 relative to said associated piston. As a corollary, the associated piston is capable of driving the actuating rod 36 in the second direction in the event of a deviation from the neutral position.

[0092] [Fig.7] shows an anti-roll device 30 for a motor vehicle anti-roll system according to a third embodiment. The motor vehicle corresponds to that shown in relation to [Fig.1].

[0093] The anti-roll device 30 is substantially similar to that of the first embodiment. It differs, however, in that the same valve 52 is shared for the first chamber 40 and the second chamber 42. The valve 52 communicates with the first branch 48 and the second branch 50.

[0094] The drive means 60 also differ. The drive means 60 comprise a transverse rod 102 and elastic means 104. The transverse rod 102 cooperates with the first piston 56. They comprise a first axial stop 70.

[0095] According to an alternative of the invention, the drive means comprise a shoulder formed on the actuating rod.

[0096] The elastic means 104 cooperate with the second piston 58. They comprise, for example, a spring at the end of the actuating rod 36. The elastic means 104 are in the third chamber 44. They work in compression and in traction. According to an alternative of the invention, they are in the second chamber and the actuating rod passes through the second piston.

[0097] According to one embodiment of the invention, the valve is a four-way valve; the first branch and the second branch being coupled to said four-way valve. The at least one valve optionally comprises a five-way valve.

[0098] According to one embodiment, the invention proposes an anti-roll device with a non-return valve and a valve, each shared for the first chamber and the first chamber. The hydraulic circuit then has two central branches; one receiving the non-return valve, the other the valve.

[0099] The invention includes the combination of all embodiments shown by all figures, unless explicitly stated otherwise.

Claims

Claims

1. Anti-roll device (30) intended to be connected to an anti-roll bar (22) of a motor vehicle (10), the anti-roll device (30) comprising a hydraulic cylinder (32); a hydraulic circuit (34); the hydraulic cylinder (32) comprising: an actuating rod (36), a cylinder (38) with a first chamber (40), a second chamber (42) opposite the first chamber (40); the hydraulic circuit (34) comprising: a hydraulic accumulator (46) intended to receive a pressurized hydraulic fluid, a first branch (48) between the first chamber (40) and the hydraulic accumulator (46), a second branch (50) between the second chamber (42) and the hydraulic accumulator (46), at least one valve (52), at least one non-return valve (54) capable of blocking a flow of hydraulic fluid from the hydraulic accumulator (46) to the cylinder (38);characterized in that the hydraulic cylinder (32) comprises a first piston (56) movable relative to the actuating rod (36) and delimiting the first chamber (40), a second piston (58) movable relative to the actuating rod (36) and delimiting the second chamber (42); the cylinder (38) further having a third chamber (44) between the first piston (56) and the second piston (58); the hydraulic cylinder (32) comprises means (60) for driving the actuating rod (36) by the first piston (56) towards the second chamber (42), and by the second piston (58) towards the first chamber (40) in order to move the actuating rod (36) towards a neutral position.;

2. Anti-roll device (30) according to claim 1, characterized in that the drive means (60) comprise a first axial stop (70) capable of driving the first piston (56) towards the first chamber (40), and a second axial stop (72) capable of driving the second piston (58) towards the second chamber (42).

3. Anti-roll device (30) according to one of claims 1 to 2, characterized in that the cylinder (38) comprises a first seat (74) capable of holding the first piston (56) at a first end of the first chamber (40), and a second seat (76) capable of holding the second piston (58) at a second end of the second chamber (42).

4. Anti-roll device (30) according to one of claims 1 to 3, ca- characterized in that the at least one valve (52) comprises a first valve (78) in the first branch (48), and a second valve (80) in the second branch (50).

5. Anti-roll device (30) according to one of claims 1 to 4, characterized in that the at least one non-return valve (54) comprises a first non-return valve (84) associated with the first branch (48), and a second non-return valve (86) associated with the second branch (50); preferably the first branch (48) comprises a first bypass (88) receiving the first non-return valve (84), the second branch (50) comprises a second bypass (90) receiving the second non-return valve (86).

6. Anti-roll device (30) according to one of claims 1 to 5, characterized in that the drive means (60) are arranged in the third chamber (44), preferably the drive means (60) comprise a cylindrical body (62).

7. Anti-roll device (30) according to one of claims 1 to 6, characterized in that the actuating rod (36) passes through the first piston (56); preferably the cylinder (38) comprises an internal surface (64), the first piston (56) comprising an external seal (66) cooperating with said internal surface (64), and an internal seal (68) cooperating with the actuating rod (36).

8. Anti-roll device (30) according to one of claims 1 to 7, characterized in that the second piston (58) comprises a drive surface (92) in the extension of the actuating rod (36), preferably, the second piston (58) comprises a sealed plate forming a seal between the second chamber (42) and the third chamber (44).

9. Anti-roll device (30) according to one of claims 1 to 8, characterized in that the first piston (56) comprises a first outer diameter (94), the second piston (58) comprises a second outer diameter (96), the drive means (60) comprise a third outer diameter (98) smaller than the first outer diameter (94) and the second outer diameter (96).

10. Motor vehicle (10) comprising an anti-roll system (18) with an anti-roll bar (22) and an anti-roll device (30) coupled to the anti-roll bar (22), characterized in that the anti-roll device (30) is in accordance with one of claims 1 to 9, preferably the anti-roll bar (22) comprises a first side and a second transverse side directly opposite the first side, the hydraulic cylinder (32) being fixed to the first side, and the anti-roll system (18) further comprises a rigid connecting rod (28) fixed to the second side.

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