Abstract
A device for volume compensation of damping liquid for a damper includes a hollow cylindrical main body containing the damping fluid. A rod extends through an end of the main body to the interior thereof. The rod is secured to a piston inside the body, which divides a compression chamber from an expansion chamber. A compensation chamber is connected to the compression and expansion chambers via internal channels of the rod and piston. A plurality of orifices in the piston open into the compression chamber and into the expansion chamber. A rigid slider moves freely in translation through, around or inside the piston and/or the rod and closes and opens the orifices to connect the compensation chamber to the expansion chamber (or, respectively, the compression chamber) in the compression (or, respectively, expansion) phases. The device may be used in vehicle wheel suspension assemblies.
Claims
1. A device for volume compensation of a damping liquid for a damper, comprising: at least one hollow cylindrical Main Body containing a fluid and having at least one end provided with an axial passage for the passage, sealing and guiding of a Rod, the Rod being secured to a Main Piston moving in translation inside the Main Body and dividing an interior of the Main Body into two different working chambers, one constituting a Compression Chamber and the other constituting an Expansion Chamber, the Compression Chamber and the Expansion Chamber being directly connected to one another via one or more internal channels in the Piston for the passage of the fluid through the Piston and one or more compensation Orifices in the region of the Piston that open into the Compression Chamber and into the Expansion Chamber; shutoff Valves for the Compensation Orifices that open into the Compression Chamber and into the Expansion Chamber; and at least one rigid component which is interposed between the shutoff Valves opening into the Compression Chamber and into the Expansion Chamber, the rigid component being able to move in translation in the axial direction of the Rod and of the Main Body, between a first end position in which the Compensation Orifices that open into the Expansion Chamber are shut off by the dedicated valve(s), while the Compensation Orifices that open into the Compression Chamber are not shut off by the dedicated valve(s), and a second end position, referred to as the compression position, in which the Compensation Orifices that open into the Compression Chamber are shut off by the dedicated valve(s), while the Compensation Orifices that open into the expansion Chamber are not closed by the dedicated valve(s), the compensation Orifices and the rigid component being positioned such that it is impossible to simultaneously close both the compensation Orifices that open into the Compression Chamber and the compensation Orifices that open into the Expansion Chamber, and such that the sum of the cross sections of the compensation Orifices that are not shut off by the actuating rigid component allow for a direct passage of oil; wherein the rigid component is arranged so as to move freely in translation through a Passage formed in the region of the Piston, which passage is different from the or said Internal Channels.
2. The device of claim 1, wherein the shutoff Valves comprise two flexible plates that are fixed on either side of the Piston and are secured thereto, the plates being capable of moving from a shut-off position in which the plates are arranged so as to be placed against the piston so as to shut off the compensation Orifices to an open position in which they are moved apart from the piston under a thrust action of the rigid component, thus freeing the compensation orifices.
3. The device of claim 1, wherein the rigid component comprises a pin moving in translation through a passage passing through the Piston.
4. The device of claim 3, wherein the shutoff valves are arranged at the end of the pin.
5. The device of claim 1, wherein the shutoff valves and the rigid component form a single piece.
6. The device of claim 1, wherein the passage through which the rigid component moves in translation is arranged between the piston and the piston body.
7. The device of claim 6, wherein the rigid component is in contact with the Main Body in the radial direction.
8. The device of claim 1, wherein the rigid component passes through the Piston in a discontinuous cross section.
9. The device of claim 6, wherein: the rigid component closes an oil Volume on the compression side during a compression phase, and on the expansion side during an expansion phase, that reduces the approach of the rigid component toward its end position; the shape of the rigid component being such that the Volume becomes closed before solid interaction of the rigid component with the Piston; and the oil Volume being connected to the Expansion Chamber or the Compression Chamber via a Hydraulic Circuit that further comprises a device of the non-return type that allows for the movement of oil solely from the Expansion Chamber (or, respectively, Compression Chamber) toward the Volume.
10. The device of claim 1, wherein the rigid component and the Piston are of a complementary shape that allows for the closure of the orifices in a progressive manner, and wherein the Orifices are entirely shut off before any solid contact between the rigid component and the Piston.
11. The device of claim 1, further comprising a Compensation Chamber connected directly to the Compression Chamber and to the Expansion Chamber.
12. The device of claim 1, wherein the Compensation Chamber is connected to the Compression Chamber and to the Expansion Chamber via an inner axial channel of the Rod which is fluidically connected to the internal channel of the Piston.
13. The device of claim 12, wherein: the Compensation Chamber is secured to the Rod; the Compensation Chamber is located opposite the Piston; and the Compensation Chamber is located outside of the main Body.
14. The device of claim 2, wherein the rigid component comprises a pin moving in translation through a passage passing through the Piston.
15. The device of claim 14, wherein the shutoff valves are arranged at the end of the pin.
16. The device of claim 15, wherein the shutoff valves and the rigid component form a single piece.
17. The device of claim 2, wherein the passage through which the rigid component moves in translation is arranged between the piston and the piston body.
18. The device of claim 17, wherein the rigid component is in contact with the Main Body in the radial direction.
19. The device of claim 3, wherein the rigid component passes through the Piston in a discontinuous cross section.
20. The device of claim 3, further comprising a Compensation Chamber connected directly to the Compression Chamber and to the Expansion Chamber.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0055] The accompanying drawings illustrate the present disclosure:
[0056] FIGS. 1 and 2 are simplified schematic views, in longitudinal cross section, of a damper intended for locating the main elements and specifying the position of chambers, referred to as positive and negative, during compression (FIG. 1) and expansion (FIG. 2) phases;
[0057] FIG. 3 is a simplified schematic view, in longitudinal cross section, of the main elements of a damper equipped with an internal Compensation Chamber;
[0058] FIG. 4 is a simplified schematic view, in longitudinal cross section, of the main elements of a damper equipped with an external Compensation Chamber;
[0059] FIG. 5 is a simplified schematic view, in longitudinal cross section, of a first embodiment of the present disclosure;
[0060] FIGS. 6-9 are simplified schematic views, in longitudinal cross section, of the first embodiment of the slider, specifying the hydraulic paths taken by the fluid during the compression (FIG. 7), expansion (FIG. 9) and transitory (FIGS. 6 and 8) phases;
[0061] FIG. 10 is a simplified schematic view, in longitudinal cross section, of a variant of the present disclosure, with no variation in the volume of the Rod in the damper;
[0062] FIGS. 11 and 12 are simplified schematic views, in longitudinal cross section, of a second embodiment of the Slider, during compression (FIG. 11) and expansion (FIG. 12) phases;
[0063] FIG. 13 is a simplified schematic view, in longitudinal cross section, of a third embodiment of the Slider (in this case in position during an expansion phase);
[0064] FIGS. 14-17 are simplified schematic views, in longitudinal cross section, of a third embodiment of the Slider, during compression (FIG. 15), expansion (FIG. 17) and transitory (FIGS. 14 and 16) phases; and
[0065] FIGS. 18-21 are simplified perspective views of a Rod/Piston assembly according to a fourth embodiment, in a perspective view (FIG. 18) and in longitudinal cross section during compression (FIG. 19) and expansion (FIG. 20) phases.
[0066] For reasons of improved clarity, the identical or similar elements (i.e., those having the same function(s)) of the different figures are indicated by identical reference signs in all the figures.
DETAILED DESCRIPTION
[0067] FIGS. 1-4 are two-dimensional schematic views showing dampers in simplified cross section, in order to define and name the various elements that are conventionally found in the dampers, and the roles of which have been set out above. Throughout the text, these elements are provided with a capital letter in order to denote that they are precisely defined. All these elements are referenced in the drawings.
[0068] For all the drawings, the double arrows represent the direction of movement of the Rod (2), and thus of the Piston (3) that is linked thereto.
[0069] For all the drawings, (−) denotes a depression, i.e., a pressure less than or equal to the static pressure of the damper. It is recalled that the static pressure of the damper is the initial pressure in the absence of movement of the Rod (2).
[0070] For all the drawings, (+) denotes an overpressure, i.e., a pressure greater than or equal to the static pressure of the damper.
[0071] FIGS. 1-4, as well as all the others, show the elements described above, such as the Main Body (1) that contains the damping fluid, the Rod (2), the role of which is to re-transmit the outside forces, the Piston or Main Piston (3), the role of which is to transmit, to the Rod, the forces resulting from internal pressure losses, the Compression Chamber (4), the pressure of which increases in the compression phase and reduces in the expansion phase, the Expansion Chamber (5), the pressure of which increases in the expansion phase and reduces in the compression phase, the Energy Dissipation Device (6), the Hydraulic Circuits (7), which allow for the circulation of the oil between the Compression and Expansion Chambers, the Compensation Chamber (8), which makes it possible to compensate the variations in the oil volume inside the damper, and the separation device between the oil and the compressible element of the Compensation Chamber, which is referred to as the Floating Piston (9), in the interest of simplification, even though other systems (membrane, etc.) exist.
[0072] FIG. 3 shows, in particular, a damper, the Compensation Chamber (8) of which is directly connected to the Compression Chamber. The disadvantages of such a solution have been explained above.
[0073] FIG. 4 shows, in particular, a damper, the Compensation Chamber (8) of which is connected “behind” the Energy Dissipation Device (6), and the advantages and limitations of which have been explained above.
[0074] FIG. 5 is a two-dimensional schematic view showing an embodiment of a damper that complies with all the requirements of the present disclosure.
[0075] In order to achieve this, the device according to the present disclosure comprises at least one hollow cylindrical Main Body (1) containing a damping fluid, at least one of the ends of which is provided with an axial passage for the passage, sealing and guiding of a Rod (2), the Rod being secured to a Main Piston (3) that moves in translation inside the Body (1) and divides it into two different working chambers, one constituting a Compression Chamber (4) and the other constituting an Expansion Chamber (5). An Energy Dissipation Device (6) being offset outside the Main Body (1) and thus comprising a Hydraulic Circuit (7) that allows for the circulation of the oil between the Compression and Expansion Chambers.
[0076] According to this embodiment, the device comprises a Compensation Chamber (8) that is connected directly to the Compression Chamber (4) AND to the Expansion Chamber (5) via Internal Channels (10) in the Rod (2) and/or in the Piston (3), and thus one or more Compensation Orifices (11) in the region of the Piston (3) that open into the Compression Chamber (4) AND into the Expansion Chamber (5). The Slider (12) is a first embodiment, the operation of which is set out in detail in FIGS. 6-9. In this case, the Slider (12) is a single piece that moves freely in translation around the Piston (3). In this embodiment, the Slider (12) is formed of a rigid component forming a sleeve arranged between the Main Body (1) and the Piston (3), the piece forming the sleeve having, at each end, a lower flange forming the shutoff Valves of the compensation orifices (11). In this embodiment, the shutoff Valves thus form a single piece with the rigid component forming the sleeve.
[0077] In FIGS. 6-9, the dotted arrows indicate the path and the displacement direction of the oil.
[0078] FIG. 6 corresponds to the start of a compression phase, i.e., the transitory compression phase. The Rod (2) moves toward the Compression Chamber (in this case to the right). The pressure of the Compression Chamber increases, which creates a displacement of oil from the Compression Chamber toward the Expansion Chamber, through the Compensation Orifices (11) and the Internal Channels (10). The oil thus does not pass through the Energy Dissipation Device (in this case external); there is no energy loss, no damping, and thus no reaction forces opposing the displacement of the rod (2). A filtration phenomenon thus occurs. During a compression phase, the Rod (2) enters the Main Body. The oil volume replaced by the volume of the entering Rod (2) thus has to leave the Main Body, because an “incompressible” fluid is present. The oil volume thus travels from the Compression Chamber toward the Compensation Chamber, via the Internal Channels (10), as is shown by the dotted arrows.
[0079] FIG. 7 corresponds to the “real” compression phase, i.e., following the shut-off of the Compensation Orifices (11) by the Slider (12) on the compression side. As the Compensation Orifices (11) are shut off, the oil cannot directly rejoin the Expansion Chamber, but is forced to move toward the external Energy Dissipation Device. Dissipation of energy thus occurs. A damping phenomenon thus occurs. On account of the presence of the Rod (2) in the expansion chamber, the movement of the Piston (3) toward the Compression Chamber displaces a volume of oil that is larger than the volume available in the Expansion Chamber. The excess oil then returns to the Compensation Chamber, via the Compensation Orifices (11), open on the expansion side, and the Internal Channels (10).
[0080] FIG. 8 corresponds to the start of an expansion phase, i.e., the transitory expansion phase. The Rod (2) moves toward the Expansion Chamber (in this case to the left). The pressure of the Expansion Chamber increases, which creates a displacement of oil from the Expansion Chamber toward the Compression Chamber, through the Compensation Orifices (11) and the Internal Channels (10). The oil thus does not pass through the Energy Dissipation Device; there is no energy loss, no damping, and thus no reaction forces opposing the displacement of the rod (2). A filtration phenomenon thus occurs. During an expansion phase, the Rod (2) leaves the Main Body. The volume of oil released by the volume of the exiting Rod (2) thus has to be compensated. The oil volume thus travels from the Compensation Chamber toward the Compression Chamber, via the Internal Channels (10), as is shown by the dotted arrows.
[0081] FIG. 9 corresponds to the “real” expansion phase, i.e., following the shut-off of the Compensation Orifices (11) by the Slider (12) on the expansion side. As the Compensation Orifices (11) are shut off, the oil cannot directly rejoin the Compression Chamber, but is forced to move toward the external Energy Dissipation Device. Dissipation of energy thus occurs. A damping phenomenon thus occurs. On account of the presence of the Rod (2) in the expansion chamber, the movement of the Piston (3) toward the Expansion Chamber displaces a volume of oil that is smaller than the volume available in the Compression chamber. The oil volume is thus compensated by the displacement of oil from the Compensation Chamber toward the Compression Chamber, via the Compensation Orifices (11), open on the compression side, and the Internal Channels (10).
[0082] FIG. 10 shows an embodiment of the present disclosure, in the absence of a Compensation Chamber. In this example, the Rod (2) is “continuous.” Its movement thus does not cause any variation in the volume available for the oil. In this case, the present disclosure can be used for the single aim of achieving the filtration phenomenon explained above. In this case, the solution is achieved using the same type of Slider (12) as above. The advantage thereof is that it is simple in shape, and that, being in contact with the Body, by virtue of the friction this represents, it is naturally and quickly located in the correct position for allowing the shutoff and freeing of the Compensation Orifices (11).
[0083] FIGS. 11 and 12 show a second embodiment of the Slider (12). In this case, the Slider (12) and the Piston (3) form a single piece. The “Piston/slider” (3-12) is thus directly in translation on the Rod (2). This embodiment results in a reduction in the number of parts.
[0084] FIG. 11 shows this embodiment during a compression phase. It is noted here that the Compensation Chamber (not visible in the figure) is connected only to the Expansion Chamber (to the left), via the Internal Channels (10).
[0085] FIG. 12 shows this embodiment during an expansion phase. It is noted here that the Compensation Chamber (not visible in the figure) is connected only to the Compression Chamber (to the right), via the Internal Channels (10).
[0086] FIG. 13 shows a third embodiment of the Slider (12). In this case, the Slider (12) passes through the Piston (3) in a non-discontinuous cross section (for example, cylindrical). This embodiment results in insulation of the Slider (12) from transient forces between the Rod (2), the Piston (3) and the body (not shown in the figure), and in thus guaranteeing a translation of the device of optimized quality and responsiveness.
[0087] FIGS. 14-17 show a particular embodiment of this type of “continuous” Slider during the phases of start of compression (FIG. 14), compression (FIG. 15), start of expansion (FIG. 16), and expansion (FIG. 17). During the start of the expansion phase, the Slider (12) closes an oil volume (16) that reduces as the Slider approaches its end position (shutoff of the Compensation Orifices (11)). The arrow (15) shows the direction of movement of the Slider (12). The shape of the Slider is such that the volume (16) is closed before the “solid” interaction between the Slider (12) and the Piston (3). The confinement of this volume creates a hydraulic stop. The oil volume is connected to a Hydraulic Circuit (13) that is connected to the expansion Chamber and comprises a device of the non-return type (14) that makes it possible to re-supply the oil volume during the phase change, and to displace the Slider (12) again. The system operates for just one side of the piston. Since the Slider (12) is continuous, an equivalent system is present on the other side of the piston. A hydraulic circuit equivalent to the hydraulic circuit (13) is thus connected to the Compression Chamber. In this embodiment, the Slider (12) is formed by a rigid pin that passes through a bore formed in the Piston (3), different from the internal channel(s) (10) for the passage of fluid, the pin being provided at least end of an internal radial extension and an external radial extension, the extensions ensuring the function of the shutoff Valves. In this embodiment, the shutoff Valves thus form a single piece with the pin.
[0088] FIGS. 18-21 show a fourth embodiment. In this embodiment, the shutoff Valves are secured not to the Slider (12) but to the Piston (3). More particularly, the shutoff Valves comprise two flexible plates (120) fixed on either side of the Piston (3) and secured thereto. The Sliders (12) comprise pins mounted in the passages (20) passing through the Piston (3) and opening on either side of the Piston (3), in the expansion chamber (5) and in the compression chamber (4). In the embodiment shown (FIG. 18), the Piston (3) comprises three passages (20) that accommodate, respectively, a pin (12) and three internal channels (10) allowing for the passage of oil. The pins are of a length sufficient for ensuring the “detachment” of the plates (120) from the Piston (3).
[0089] As shown in FIGS. 19 and 20, the plates are capable of moving from a shut-off position in which the plates are arranged so as to be placed against the piston so as to shut off the compensation Orifices (11) to an open position in which they are moved apart from the piston under the thrust action of the pins, thus freeing the compensation orifices (11) under the action of the pins.
[0090] Thus, FIG. 19 shows the “real” compression phase. The plate on the compression chamber (4) side is placed against the face of the Piston (3) with which it is associated, shutting off the compensation Orifices (11) that open into the Compression Chamber (4), while the plate on the expansion chamber (5) side is pushed back by the Sliders (12), thus opening the compensation Orifice (11) that opens into the expansion Chamber (5).
[0091] FIG. 20 shows the “real” expansion phase. The plate on the expansion chamber (5) side is placed against the face of the Piston (3) with which it is associated, shutting off the compensation Orifices (11) that open into the expansion Chamber (5), while the plate on the compression chamber (4) side is pushed back by the Sliders (12), thus opening the compensation Orifice (11) that opens into the compression Chamber (4).
[0092] By selecting the rigidity of the Valves and the length of the pins, it is possible to adjust the responsiveness of the system and its filtration range (filtered frequencies and amplitudes), i.e., the range over which the expansion Chambers (5) and the compression Chamber (4) are directly connected, and in order for the piston to be unable to transmit a force (no oil movement). FIG. 21 shows the position of the Valves in the filtration phase.
[0093] The present disclosure (and these various embodiments) is particularly suitable for the damper design used in the front or rear suspension systems of land vehicles, in particular, bicycles, motorbikes, cars, etc.
[0094] The present disclosure is described above by way of example. It will be understood that a person skilled in the art is able to implement different variants of the present disclosure.
LIST OF REFERENCE SIGNS
[0095] (1) Main Body [0096] (2) Rod [0097] (3) Piston [0098] (4) Compression Chamber [0099] (5) Expansion Chamber [0100] (6) Energy Dissipation Device [0101] (7) Hydraulic Circuits [0102] (8) Compensation Chamber [0103] (9) Floating Piston [0104] (10) Internal Channels [0105] (11) Compensation Orifices [0106] (12) Slider [0107] (13) Hydraulic Circuits [0108] (14) Non-return Device [0109] (15) Direction of displacement of the Slider [0110] (16) “confined” Oil Volume
