Variable inertia suspension damper for a motor vehicle

Abstract

The invention relates to a motor vehicle suspension damper (20). The damper comprises: a chamber (26); an inertia circuit (38) connected to the chamber via a first connection zone (40) and a second connection zone (42); and an actuation rod (30) of a piston (32). The piston moves axially between the first connection zone and the second connection zone in order to generate an inertial force opposing the movements of the actuation rod. The second connection zone comprises a plurality of second passages (46) connecting the chamber to the inertia circuit, the second passages being spaced apart axially and distributed along the inertia circuit. The damper further comprises a movable seal (50) and resilient means (52) connecting the movable seal to the actuation rod in order to selectively close at least one of the second passages so as to change the length of the inertia circuit connected to the chamber.

Description

Description Title of the invention: Variable inertia suspension shock absorber for a motor vehicle

[0001] The present invention claims priority from French application 2301644 filed on February 23, 2023, the content of which (text, drawings and claims) is incorporated herein by reference.

[0002] The invention relates to the field of shock absorbers for motor vehicle suspension. The invention relates to an inertia shock absorber for a motor vehicle suspension system. The invention also relates to a motor vehicle equipped with suspension systems.

[0003] A motor vehicle consists of several suspension systems, each connected to the structure. Each suspension system includes a wheel and a suspension system. A suspension system commonly includes a swing arm, a spring, and a shock absorber capable of filtering the swing arm's oscillations transmitted by the wheel depending on the roughness of the road. A suspension system thus optimizes driving comfort and road holding; and therefore safety.

[0004] Since damping requirements vary depending on vehicle use and road conditions, it is advisable to use dampers with variable damping coefficients. For example, damping can vary depending on the amplitude of the suspension shock absorber loads.

[0005] US4700815 A discloses a motor vehicle comprising a variable damper suspension. The variable damper comprises a cylinder with an inner surface, and a valved piston inside the cylinder. The valved piston sweeps a section along which the inner surface has a variable-width groove. This groove forms a bypass passage around the valved piston. Thus, the damper has variable damping characteristics depending on the depression of the piston during its oscillations.

[0006] US20210268860A1 details a motor vehicle with an adjustable shock absorber assembly. The shock absorber assembly includes a main chamber containing a working fluid, a damping piston coupled to a piston shaft. The damping piston is disposed in the main chamber to divide the main chamber into a compression-side fluid chamber and a rebound-side fluid chamber.

[0007] The shock absorber assembly further includes an auxiliary chamber and a free internal piston separating the auxiliary chamber from the compression-side fluid chamber. The auxiliary chamber houses a pump. In one embodiment, the pump is used to selectively fill and empty a third fluid chamber of a spring preload device. Thus, an internal distance between the free internal piston and the pump is modulated; thereby resulting in ride height control.

[0008] Document US2013 / 0037362A1 discloses a shock absorbing device, in particular for motor vehicle suspension. The shock absorbing device comprises a cylinder, a movable rod inside the cylinder, and a fluid inside the cylinder. It A first piston is provided rigidly attached to the rod with an orifice, and a spring-loaded piston slidably attached to the rod. The device further comprises a helical tube located outside the cylinder creating a sealed path for the flow and return of fluid into the cylinder via two orifices. The movement of the rod causes the fluid to flow through the helical tube which generates an inertial force due to the moving mass of the fluid. The first piston is provided with damping means in the form of the orifice. The spring-loaded piston provides the effect of a parallel spring. The device is equipped with an external chamber and a floating piston to receive the fluid displaced by the rod. This chamber allows the device to be pressurized.

[0009] Alternatively, the device has a second cylinder in which the spring piston is arranged; the second cylinder being associated with a second helical tube; forming a second inertial damper acting in parallel.

[0010] During use, the vehicle's mass changes depending on its load. Indeed, the number of passengers and the presence of luggage influence the total mass of the vehicle. In such cases, it is necessary to modulate the damping, and in particular to increase it in order to respect a predefined behavior. Furthermore, it is interesting to propose a passive solution, allowing free adjustment of the actuator and external energy source.

[0011] The invention aims to address at least one of the problems or drawbacks encountered in the prior art. In particular, the invention aims to change the behavior of a shock absorber as a function of the load of a motor vehicle. The invention also aims to adapt the damping of an inertial shock absorber as a function of the load of the vehicle. The invention also aims to optimize the safety, adjustment precision and simplicity of a suspension shock absorber of a motor vehicle.

[0012] According to a first aspect, the invention proposes a shock absorber for a motor vehicle suspension system, the shock absorber comprising: a chamber with an axial direction, an inertia circuit connected to the chamber via a first connection zone and a second connection zone axially spaced apart; an actuating rod; a piston connected to the actuating rod and arranged in the chamber, the piston being able to move axially between the first connection zone and the second connection zone so as to drive liquid into the chamber and the inertia circuit in order to generate an inertia force opposing the movements of the actuating rod; remarkable in that the second connection zone comprises several second passages connecting the chamber to the inertia circuit, said second passages being axially spaced apart and distributed along the inertia circuit;the damper further comprises a movable shutter capable of moving axially along the second connection zone; and elastic means connecting the movable shutter to the actuating rod so as to axially move the movable shutter in response to a movement of the actuating rod in order to selectively close at least one of the second passages to change a length of inertia circuit communicating with the chamber.;

[0013] It will be understood that the invention proposes a motor vehicle suspension shock absorber with an inertia circuit, one end of which is connected to a chamber by means of different passages which are selectively opened and closed by a movable shutter which is controlled by an actuating rod of a piston via elastic means.

[0014] Preferably, the movable shutter comprises a through conduit with a first end towards the piston, and a second end capable of selectively communicating with one of the second passages.

[0015] Preferably, the movable shutter comprises a leak orifice extending axially and having a width less than the width of each second passage.

[0016] Preferably, the movable shutter comprises a leak orifice extending axially and having a width at least five times less than the width of each second passage.

[0017] Preferably, the movable shutter comprises an inner tube with an outer collar capable of sliding against the inner surface of the chamber, and an outer tube around the inner tube and axially at a distance from the outer collar; the movable shutter comprising an annular passage between the inner tube and the outer tube; the outer collar and the outer tube forming closure surfaces capable of sliding along the second connection zone.

[0018] Preferably, the external collar and the external tube are axially spaced apart by a first distance greater than or equal to an internal width of second passages.

[0019] Preferably, the second passages have an axial spacing pitch, the first distance being less than or equal to said axial spacing pitch.

[0020] Preferably, the inertia circuit comprises a plurality of turns in the axial direction, the plurality of turns comprising second turns each associated with one of the second passages.

[0021] Preferably the second passages form an alignment.

[0022] Preferably, the elastic means comprise a first spring between the piston and the movable shutter, and / or a second spring against the movable shutter and opposite the piston.

[0023] Preferably, the movable shutter comprises a first face oriented towards the piston, and a second face axially opposite the first face and capable of moving along the second connection zone.

[0024] Preferably, the piston is between the first connection zone and the movable shutter.

[0025] Preferably, the elastic means bear against the piston, the piston being rigidly connected to the actuating rod.

[0026] Preferably, the first connection zone comprises a first passage connecting the chamber to the inertia circuit, in particular to a first end of the inertia circuit.

[0027] Preferably, the piston comprises a first outside diameter, and the movable shutter comprises a second outside diameter equal to the first outside diameter.

[0028] Preferably, the piston is a first piston, and the shutter comprises a second piston.

[0029] Preferably, the second passages comprise second orifices opening into the chamber and forming at least one axial alignment.

[0030] Preferably, the second passages are each associated with one of the turns of the inertia circuit.

[0031] Preferably, the coils are wound around the chamber.

[0032] Preferably, the shutter has a hollow annular shape.

[0033] Preferably, the chamber comprises a guide cooperating with the shutter, said guide extending along the second passages.

[0034] Preferably, the second spring is configured to exert a force against the shutter towards the first.

[0035] According to another aspect, the invention relates to a shock absorber for a motor vehicle suspension system, the shock absorber comprising: a chamber, a piston in the chamber, an inertia circuit with a first zone for connection to the chamber, and a second zone for connection to the chamber; remarkable in that the second zone comprises a plurality of orifices distributed along the inertia circuit, the shock absorber further comprising a shutter in the chamber and configured to selectively close at least one of the orifices of the plurality of orifices, and elastic means connected to the actuating rod and to the shutter so as to modify the position of the shutter as a function of an average position of the actuating rod.

[0036] According to another aspect, the invention relates to a shock absorber for a motor vehicle suspension system, the shock absorber comprising: a chamber defining an axial direction; an inertia circuit with a first zone of connection to the chamber and a second zone of connection to the chamber; a piston mounted movably in the chamber between the first zone of connection and the second zone of connection, the piston being capable of driving a liquid into the chamber and the inertia circuit during its axial movements, the inertia circuit being capable of generating a reaction force to the axial movements of the piston in the chamber; an actuating rod connected to the piston and to a movable suspension part of the motor vehicle; elastic means capable of being driven by the actuating rod;remarkable in that the second connection zone comprises a plurality of second connection orifices of the chamber to the inertia circuit which are distributed along the inertia circuit, the shock absorber further comprises a shutter connected to the elastic means and configured so as to selectively close at least one of the second connection orifices in order to modulate the effective length of the inertia circuit connected to the chamber.;

[0037] According to another aspect, the invention provides a motor vehicle comprising a wheel, a structure, a suspension system with a movable arm connecting the wheel to the structure of the motor vehicle and a shock absorber, remarkable in that the shock absorber is in accordance with the invention.

[0038] Preferably, the shock absorber is filled with liquid with a density greater than or equal to 1.10.

[0039] Each feature introduced by the expression “preferably” given in relation to one of the aspects of the invention applies to all other aspects of the invention.

[0040] The invention will be well understood and other aspects and advantages will appear clearly on reading the following description, given with reference to the appended and listed figures. below.

[0041] Figure 1 is a side view of a motor vehicle according to the invention.

[0042] Figure 2 shows a cross-section of a shock absorber of a motor vehicle suspension system according to the invention; the shock absorber being in a deployed configuration.

[0043] Figure 3 shows a sectional view of a shock absorber of a motor vehicle suspension system according to the invention; the shock absorber being in a retracted configuration.

[0044] Figure 4 is a section of a movable shutter of a shock absorber of a motor vehicle suspension system according to 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 shock absorber to which it relates. It is understood that the term "comprise" includes the terms "consist of". The terms "external" and "internal" will refer respectively to that which is oriented towards the outside of the shock absorber and towards the inside of the shock absorber.

[0046] In this description, the term "front" refers to the principal direction of travel of the vehicle. The term "rear" refers to the opposite of the front of the vehicle.

[0047] In this description, the terms "axial" and "axially" correspond to an orientation following the direction of compression and expansion of the shock absorber.

[0048] In this description, the ranges of values ​​include the limits which delimit them.

[0049] In this description, the technical characteristics are defined in the shock absorber mounting configuration, unless explicitly stated otherwise.

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

[0051] Figure 1 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 even a main frame of the motor vehicle. The structure 12 delimits different compartments of the motor vehicle 10, including the passenger compartment, the cargo compartment, the engine compartment (not shown).

[0053] The structure 12 supports various components of the motor vehicle including the engine; a steering system; suspension systems 14. With the wheels 16 of the front and rear axles, the suspension systems 14 form connections to the ground. The suspension systems 14 comprise movable arms 18 such as suspension triangles. The movable arms 18, or suspension arms, are in particular pivoting arms. The wheels 16 are thus connected to the structure 12 in a movable manner; allowing a variation in ground clearance.

[0054] At least one or each suspension system 14 includes a shock absorber 20, also called a shock absorber. A shock absorber 20 opposes the movements of the movable arms 18 by dissipating energy. It converts mechanical energy into thermal energy. Each shock absorber 20 opposes the vertical displacements of the wheels 16 in compression. and in relaxation when the motor vehicle 10 encounters roughness in the road. The resistance is advantageously a function of the speed of variation of elongation of the shock absorber 20. The resistance also includes a component which is a function of the acceleration of variation of elongation of the shock absorber 20.

[0055] Suspension springs 22 elastically connect the movable arms 18 to the structure 12. The suspension springs 22 may surround the shock absorbers 20, or be offset. The suspension springs 22, like the shock absorbers 20, comprise one end connected to the structure 12, and another end on the wheel side; in particular a lower end. They may be fixed to the movable arms 18, or to steering knuckles (not shown) themselves connected to the movable arms 18. In the event of loading of the motor vehicle, the suspension springs 22 compress, and the shock absorbers retract.

[0056] The motor vehicle 10 may, for example, be a private motor vehicle or a commercial motor vehicle.

[0057] Figure 2 shows a shock absorber 20 of a motor vehicle suspension system in an unloaded configuration, i.e. when the shock absorber 20 is deployed, relaxed. The motor vehicle may correspond to that shown in connection with Figure 1.

[0058] The shock absorber 20 comprises a main body 24 of tubular shape. The main body delimits a chamber 26, also called the first chamber or internal chamber. The chamber 26 is filled with a liquid such as a lubricant. The chamber 26 has an axial direction 28 represented in the form of a central axis corresponding to the axis of revolution of the chamber 26. An auxiliary reservoir (not shown) is advantageously connected to the chamber 26 in order to compensate for variations in the volume of liquid in the chamber following the oscillations of the actuating rod 30. The actuating rod 30 is movable in translation along the axial direction 28. It is in particular connected to the structure of the motor vehicle.

[0059] The shock absorber 20 comprises a piston 32, also called the first piston or damping piston. The piston 32 is connected to the actuating rod 30. The piston 32 is able to move axially in the chamber 26 following a stress from the actuating rod 30. It comprises at least one pressure drop orifice 34, preferably two pressure drop orifices 34, making it possible to generate a resistive force opposing the movement of the piston 32. According to one option; the actuating rod 30 passes through the piston 32 in order to facilitate its fixing.

[0060] Elastic lamellae 36 associated with the pressure drop orifices 34 make it possible to adjust the behavior of the piston 32. In one direction of flow, the elastic lamellae 36 slow the flow by deforming; in the other direction the lamellae form valves closing the associated pressure drop orifice 34. Each pressure drop orifice 34 is adapted to allow flow in one of the directions of movement of the piston 32. According to one option, the elastic lamellae 36 comprise washers surrounding the actuating rod 30.

[0061] The shock absorber 20 further comprises an inertia circuit 38 connected to the chamber 26 via a first connection zone 40 and a second connection zone 42 axially distant, and preferably at the opposite ends of the chamber 26. Depending on the direction of movement of the piston 32 and therefore of flow of the liquid, these zones form an inlet and an outlet of the inertia circuit 38. The liquid may be oil, or glycol. The latter has a high density, for example greater than 1.1, in order to increase the inertia effect in the inertia circuit 38. The first connection zone 40 comprises a first passage 41 connecting the chamber 26 to the inertia circuit 38.

[0062] The piston 32 is able to move axially between the first connection zone 40 and the second connection zone 42 so as to drive the liquid in the chamber towards the inertia circuit in order to generate an inertia force opposing the movements of the piston 32, and therefore of the actuating rod 30. In order to optimize the inertia effect, the inertia circuit 38 has a plurality of turns 44. The plurality of turns 44 comprises second turns, each associated with one of the second passages. The second turns are arranged axially at the second connection zone 42.

[0063] The turns 44 are wound around the chamber 26. They are distributed over the entire axial length of the chamber 26. They are inclined at an angle of between 70° and 89° relative to the axial direction. Thus, for a movement of the piston 32, the movement of the liquid in the inertia circuit 38 is multiplied; and therefore the inertia force that it opposes to the movements of the piston 32.

[0064] The second connection zone 42 comprises several second passages 46 connecting the chamber 26 to the inertia circuit 38. The second passages 46 extend radially, that is to say perpendicular to the axis of revolution of the chamber 26. They allow their hydraulic connection at different separate and distinct points. The second passages 46 are axially spaced in the chamber 26 and distributed along the inertia circuit 38.

[0065] The second passages 46 comprise second orifices 48. The second orifices 48 form bores. They are formed in the internal surface of the chamber 26 and open there. The second passages 46 form an alignment. In this case, the second orifices 48 form an alignment on the internal surface of the chamber 26. Each second passage 46 is associated with one of the turns 44 dedicated to it. Therefore, between two successive second passages 46, the length of the inertia circuit 38 is equal to the developed length of a turn 44.

[0066] The shock absorber 20 further comprises a movable shutter 50 arranged in the chamber 26. The piston 32 and the movable shutter 50 comprise the same external diameter. The movable shutter 50 can form a second piston flexibly connected to the actuating rod 30. The piston 32 is between the first connection zone 40 and the movable shutter 50. Thus, they compartmentalize the chamber 26 into several enclosures. The movable shutter 50 is mounted to slide axially. It is able to move; at least; along the second connection zone 42. Thus, depending on the position it occupies, it manages to selectively close at least one of the second passages 46 and therefore to allow communication through at least one other second passage 46. Therefore, the length of the inertia circuit 38 hydraulically connected to the chamber 26 is a variable adjusted by the position of the movable shutter 50.

[0067] The damper 20 comprises elastic means 52 connecting the movable shutter 50 to the actuating rod 30. Generally, the elastic means 52 form drive means or connecting means. The elastic means 52 are configured to axially move the movable shutter 50 in response to a movement of the actuating rod 30, which makes it possible to move the movable shutter 50 relative to the second passages 46, and in particular relative to the second orifices 48 to selectively open or close them.

[0068] The elastic means 52 bear against the piston 32. The movable shutter 50 comprises a first face 54 oriented towards the piston 32, and a second face 56 axially opposite the first face 54. The second face 56 is arranged along the second connection zone 42. The second face 56, for example its lower surface opposite the piston 32, is capable of moving along the second connection zone 42. It is capable of axially sweeping the second passages 46.

[0069] The elastic means 52 comprise springs configured to work in compression. The elastic means 52 comprise a first spring 58 between the piston 32 and the movable shutter 50, and a second spring 60 against the movable shutter 50 and opposite the piston 32. The second spring 60 is configured to push the movable shutter 50 towards the piston 32. The first spring 58 is arranged on the first face 54, and the second spring 60 is arranged on the second face 56. They exert forces against the movable shutter 50 in opposite directions. They are optionally mounted axially prestressed. They are helical springs.

[0070] The movable shutter 50 comprises a through conduit 62. The through conduit 62 extends axially. It extends from the first face 54 towards the lateral surface 64. The lateral surface 64 forms the external surface of the movable shutter 50. The lateral surface 64 is cylindrical. The lateral surface 64 cooperates in a sealed manner with the internal surface of the chamber 26; in order to seal the second passages 46.

[0071] The damper 20 comprises a guide 66 in the chamber 26. The guide 66 extends axially along the second passages 46. The guide 66 is arranged opposite the actuating rod 30, on the side of the second face 56. The movable shutter 50 is capable of housing the guide 66. The second spring 60 is radially between the guide 66 and the movable shutter 50.

[0072] According to an alternative of the invention, the elastic means comprise a low stiffness so that in the event of movement of the actuating rod imposed by a load of the motor vehicle, the inertia of the movable shutter opposes its movement. For example, the movable shutter reaches its equilibrium position in at least 1 second (s), preferably in at least 2 s, more preferably in at least 5 s. Such durations make it possible to increase the stability of the shock absorber. Despite high-frequency oscillations of the control rod, the movable shutter remains at an average distance from said control rod. This makes it possible to decouple them, while allowing a change of position to modify the inertia damping setting.

[0073] According to an alternative of the invention, the inertia circuit comprises a coil on one side of the chamber. The coil is optionally a flat coil.

[0074] According to an alternative of the invention, the movable shutter comprises a body with an angular cylinder segment of more than 180°, said angular segment being against the second passages.

[0075] Figure 3 shows the shock absorber 20 of a motor vehicle suspension system in a loaded configuration, for example with at least 200 kg, preferably with 350 kg, more preferably with at least 500 kg. This configuration corresponds to a retracted configuration of the shock absorber 20. The motor vehicle may correspond to that shown in relation to one of Figures 1 to 2.

[0076] The damper 20 is compressed. The actuating rod 30 enters the chamber 26, pushing the piston 32 towards the movable shutter 50. Thanks to the elastic means 52, the movement of the actuating rod 30 is communicated to the movable shutter 50. The first spring 58 and the second spring 60 are compressed. According to an option of the invention, the first spring 58 comprises a first stiffness, and the second spring 60 comprises a second stiffness less than the first stiffness. This difference in stiffness makes it possible to promote the travel of the movable shutter 50 following a given depression of the actuating rod 30.

[0077] In the present loading state, the movable shutter 50 reaches the bottom 68 of the chamber 26 from which the second spring 60 extends. The movable shutter 50 extends axially along the entire second connection zone 42. The movable shutter 50 is surrounded by the second turns 70.

[0078] Thus, it allows circulation of liquid with the second passage 46 towards the bottom 68; and blocks circulation with the other second passages 46. In contrast to the configuration presented in relation to FIG. 2, the length of the inertia circuit 38 which is hydraulically connected to the chamber 26 becomes longer since the number of turns 44 allowing circulation towards the chamber 26 increases. Therefore, the damping by inertia effect is stronger. Therefore, in the event of loading of the vehicle, the damping increases automatically; that is to say without the need for an external actuator and a specific energy source. This optimizes the reliability, the adjustment precision and the simplicity of the shock absorber.

[0079] In the present illustration, the second connection zone 42 comprises four second passages 46. However, any other number of second passages is possible in order to increase the fineness of damping adjustment.

[0080] The second passages 46 comprise connection orifices 48 each associated with a separate turn 44 of the inertia circuit 38. Furthermore, in the event of intermediate loading, at least one through conduit 62 reaches the other second passages 46 placed between those at the ends of the plurality of second passages 46.

[0081] According to an alternative of the invention, the movable shutter has an axial height greater than or equal to an inner diameter of the second passage, and the plurality of second passages comprises two second passages. Thus, the movable shutter allows fluid circulation via one of the two second passages. This arrangement has the possibility of adjustment and compactness.

[0082] According to an alternative of the invention, the elastic means comprise a body made of elastomer material connecting the movable shutter to the actuating rod. This body makes it possible to transmit compressive and tensile forces.

[0083] Figure 4 shows a movable shutter 50 of a suspension system for a motor vehicle. The motor vehicle may correspond to that shown in relation to one of Figures 1 to 3. The elastic means are not shown for the sake of clarity. A portion of the body 24 and its turns 44 are shown in dotted lines.

[0084] The movable shutter 50 generally has an annular shape. It has a symmetry of revolution. The movable shutter 50 is a single piece. It also forms a hollow body, with a recess 72 intended to house the second spring and the guide according to the configuration, and intended to be filled with the fluid.

[0085] The movable shutter 50 comprises at least one through conduit 62 with a first end 74 towards the piston (not shown), and a second end 76 communicating selectively with at least one of the second passages 46. Thus, the movable shutter 50 forms a drawer whose position makes it possible to choose a second passage and keep it open, and therefore to adapt the length of the inertia circuit 38 in communication with the chamber 26.

[0086] Generally, the damper comprises means for braking the movable shutter 50. The movable shutter 50 comprises a leak orifice 78 extending axially. The leak orifice 78 communicates with the recess 72. The leak orifice 78 has a width that is smaller; preferably at least five times smaller; more preferably at least ten times smaller; than the width of each second passage 46. The widths are internal widths. In particular, the internal width of each second passage 46 is smaller than the internal width of the turns 44. This generates pressure losses at the second passages 46, and promotes the flow of a limited number of turns 44.

[0087] According to an alternative of the invention, the movable shutter is adjusted to the internal surface of the chamber so as to rub inside the chamber and to slow down the movements controlled by the sliding rod via the elastic means. This aspect replaces the presence of a leak orifice.

[0088] The movable shutter 50 comprises an inner tube 80 with an outer collar 82 capable of sliding against the inner surface 84 of the chamber 26, and an outer tube 86 around the inner tube 80 and axially at a distance from the outer collar 82. The inner tube 80 and the outer tube 86 are coaxial. The movable shutter 50 comprises an annular passage 88 between the inner tube 80 and the outer tube 86. Fins 89 connect the inner tube 80 to the outer tube 86. The annular passage 88 is formed by the through conduit 62.

[0089] According to an alternative of the invention, the through conduit is surrounded by the annular passage.

[0090] The external collar 82 and the outer tube 86 materialize closure surfaces 90 capable of sliding along the second connection zone and in particular the second passages 46. The closure surfaces 90 are circular. When one of the second passages 46 is between them, it communicates with the chamber 26 through the movable shutter 50.

[0091] The external collar 82 and the external tube 86 are axially spaced apart by a first distance 92 greater than or equal to an internal width 94 of second passages 46. This aspect promotes communication between one of the second passages 46 and the movable shutter 50.

[0092] According to one option, the second passages 46 have an axial spacing pitch 96. The axial spacing pitch 96 may be equal to the pitch of the turns 44. The first distance 92 is less than or equal to said axial spacing pitch 96. This aspect improves the precision of adjustment of inertia damping since when the second end 76 of the through conduit 62 is centered on one of the second passages 46, only the latter is open; the others are closed by the movable shutter 50. Furthermore, when, as in the present illustration, the through conduit 62 and / or the annular passage 88 are in communication with two successive second passages 46; they are only partially so. This makes it possible to control the length of the inertia circuit 38 (partially shown) hydraulically coupled with the chamber 26 where the oscillations of the piston which are to be damped occur.

[0093] According to an alternative of the invention, the second passages comprise several passages distributed angularly around the chamber; and the movable shutter comprises an upper surface inclined relative to a radial direction; the upper surface being configured to selectively allow a passage of fluid through the inertia circuit via one of the second passages; in particular due to pressure losses in the inertia circuit.

[0094] The invention comprises the combination of all embodiments shown by all figures and / or figures 2 to 4.

[0095] The invention includes the combination of all alternatives.

[0096] The invention comprises the combination of each of the alternatives with each embodiment shown by one of Figures 1 to 4.

[0097] These combinations optimize adjustment precision.

Claims

Claims

1. Shock absorber (20) for a suspension system (14) of a motor vehicle (10), the shock absorber (20) comprising: a chamber (26) with an axial direction (28), an inertia circuit (38) connected to the chamber (26) via a first connection zone (40) and a second connection zone (42) axially spaced apart; an actuating rod (30); a piston (32) connected to the actuating rod (30) and arranged in the chamber (26), the piston (32) being able to move axially between the first connection zone (40) and the second connection zone (42) so as to drive liquid into the chamber (26) and the inertia circuit (38) in order to generate an inertia force opposing the movements of the actuating rod (30); characterized in that the second connection zone (42) comprises several second passages (46) connecting the chamber (26) to the inertia circuit (38), said second passages (46) being axially spaced apart and distributed along the inertia circuit (38);the damper (20) further comprises a movable shutter (50) capable of moving axially along the second connection zone (42); and elastic means (52) connecting the movable shutter (50) to the actuating rod (30) so as to axially move the movable shutter (50) in response to a movement of the actuating rod (30) in order to selectively close at least one of the second passages (46) to change a length of inertia circuit (38) communicating with the chamber (26).;

2. Shock absorber (20) according to claim 1, characterized in that the movable shutter (50) comprises a through conduit (62) with a first end (74) towards the piston (32), and a second end (76) capable of selectively communicating with one of the second passages (46).

3. Shock absorber (20) according to one of claims 1 to 2, characterized in that the movable shutter (50) comprises a leak orifice (78) extending axially and having a width less than the width of each second passage (46), preferably at least five times less than the width of each second passage (46).

4. Shock absorber (20) according to one of claims 1 to 3, characterized in that the movable shutter (50) comprises an inner tube (80) with an outer collar (82) capable of sliding against the inner surface (84) of the chamber (26), and an outer tube (86) around the inner tube (80) and axially at a distance from the outer collar (82); the movable shutter (50) comprising an annular passage (88) between the inner tube (80) and the outer tube (86); the outer collar (82) and the outer tube (86) forming shutter surfaces (90) capable of sliding along the second connection zone (42).

5. Shock absorber (20) according to claim 4, characterized in that the external collar (82) and the external tube (86) are axially spaced apart by a first distance (92) greater than or equal to an internal width (94) of second passages (46); preferably the second passages (46) have a pitch axial spacing (96), the first distance (92) being less than or equal to said axial spacing pitch (96).

6. Shock absorber (20) according to one of claims 1 to 5, characterized in that the inertia circuit (38) comprises a plurality of turns (44) in the axial direction (28), the plurality of turns (44) comprising second turns (70) each associated with one of the second passages (46); preferably the second passages (46) form an alignment.

7. Shock absorber (20) according to one of claims 1 to 6, characterized in that the elastic means (52) comprise a first spring (58) between the piston (32) and the movable shutter (50), and / or a second spring (60) against the movable shutter (50) and opposite the piston (32).

8. Shock absorber (20) according to one of claims 1 to 7, characterized in that the movable shutter (50) comprises a first face (54) oriented towards the piston (32), and a second face (56) axially opposite the first face (54) and capable of moving along the second connection zone (42); preferably the piston (32) is between the first connection zone (40) and the movable shutter (50).

9. Shock absorber (20) according to one of claims 1 to 8, characterized in that the elastic means (52) bear against the piston (32), the piston (32) being rigidly connected to the actuating rod (30).

10. Motor vehicle (10) comprising a wheel (16), a structure (12), a suspension system (14) with a movable arm (18) connecting the wheel (16) to the structure (12) of the motor vehicle (10) and a shock absorber (20), characterized in that the shock absorber (20) is in accordance with one of claims 1 to 9; preferably the shock absorber (20) is filled with liquid with a density greater than or equal to 1.10.

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