Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
  • F16F9/10—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using liquid only; using a fluid of which the nature is immaterial
  • F16F9/14—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect
  • F16F9/16—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts
  • F16F9/22—Devices with one or more members, e.g. pistons, vanes, moving to and fro in chambers and using throttling effect involving only straight-line movement of the effective parts with one or more cylinders each having a single working space closed by a piston or plunger
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
  • F16F9/32—Details
  • F16F9/3207—Constructional features
  • F16F9/3235—Constructional features of cylinders
  • F16F9/325—Constructional features of cylinders for attachment of valve units
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
  • F16F9/32—Details
  • F16F9/48—Arrangements for providing different damping effects at different parts of the stroke
  • F16F9/49—Stops limiting fluid passage, e.g. hydraulic stops or elastomeric elements inside the cylinder which contribute to changes in fluid damping

Definitions

• the present invention relates to an improvement for shock absorber and more particularly to a set of improvements intended to substantially improve the technical characteristics of a shock absorber of the type comprising a double piston.
• shock absorbers use the principle of a piston rod carrying two pistons sliding in a main compression chamber around a partition separating said chamber into two working chambers, bidirectional rolling means being provided in said partition such as, for example, the damper described in international application WO 97/25497.
• the shock absorbers of the prior art using this type of damping device have many drawbacks related to their implementation, their positioning or their size. In fact, they present cavitation problems linked to the essential pressurization of the fluid reservoir and at the flow rate of the fluid return pipes between the reservoir and the working chambers of the shock absorber and are generally forced to operate while being disposed substantially horizontally.
• some shock absorbers have sealing problems and degrade quickly when a large number of successive cycles are imposed on them.
• the present invention aims to solve the above problems using simple, reliable and easy to implement means. Its objective is to present a shock absorber using the principle of the double piston capable of operating vertically and allowing easy adjustment of the various parameters of the shock absorber, said shock absorber being compact and able to withstand a large number of cycles in order to be able to be used in industrial applications such as the automobile or motorcycle, for example.
• the shock absorber of the invention is of the type comprising two pistons integral with a rod intended to slide in a main compression chamber on either side of an intermediate partition crossed by the rod to form two secondary working chambers, said working chambers being interconnected by laminating means which manage the flow rate of the damping fluid circulating between the chambers under the stress of the movement of the pistons, and is characterized in that it comprises an enclosure and supply means which replenish one of the secondary working chambers with damping fluid to compensate for fluid leaks caused or organized along the pistons.
• the shock absorber of the invention is characterized in that the make-up enclosure is produced in a dip tube secured to a first piston, and in that the supply means are constituted by a supply valve and a supply duct connecting the make-up enclosure to a secondary working chamber.
• the dip tube is fixed to the lower piston, and the make-up chamber is connected to the lower working chamber by means of a supply valve and its conduit arranged in the lower piston.
• the shock absorber of the invention is characterized in that the rod and the pistons have a fluid circulation channel connecting the external face of the piston to the top-up enclosure.
• the dip tube comprises at its lower end the low point of attachment of the shock absorber and forms with the pistons and their rod a movable subassembly relative to the shock absorber body which forms the main compression and which comprises at its upper end the top fixing point, the fluid leaks organized at the level of the upper piston being brought back by gravity into the recharging chamber of the dip tube through a bore of the rod and of the pistons.
• the rolling means connecting the secondary working chambers are formed by an external rolling block disposed at one end of the shock absorber or along the body of the shock absorber and having means for adjusting its rolling characteristics.
• the damper of the invention is characterized in that the angular position in a transverse plane of the rolling block or of the partition with respect to the fixing points is adjustable.
• the external rolling block is located at the upper end of the shock absorber and in that the body of the shock absorber comprises two tube portions concentric which define with a portion of the upper cylinder of the body two annular spaces which allow the circulation of the fluid between the working chambers and through the rolling block.
• the shock absorber includes an extension stop which has elastic return means arranged between a projection of the lower mobile assembly and a bearing surface of a stop screw integral with the upper mobile assembly.
• the shock absorber of the invention comprises external pressurizing means allowing the pressurization and the modification of the pressure of the shock absorber.
• FIGS 1 to 5 illustrate two embodiments and an alternative embodiment of the damper of the invention.
• Figures 1 to 3 show in longitudinal section the first embodiment of the damper respectively in the intermediate position, in the compression position, and in the extended position.
• Figure 4 shows in longitudinal section a second embodiment of the damper.
• Figure 5 illustrates in longitudinal section an alternative embodiment of the damper.
• the damper of the invention is of the type comprising two pistons (2, 3) carried by a piston rod (4) so as to be able to slide in a main compression chamber (5) delimited by a damper body (6).
• These two pistons (2, 3) are intended to slide in the chamber (5) filled with oil (10) on either side of an intermediate partition (7) which thus separates said main chamber (5) in two secondary working chambers (8, 9).
• the damper (1) comprises a make-up enclosure (11) and make-up means (12, 13) capable of replenishing damping fluid (10) one of the secondary working chambers (8 , 9) of the shock absorber. According to the preferred embodiments of the damper (1) of the invention, illustrated in FIGS.
• the make-up enclosure (11) is produced in a dip tube (14) fixed to one of the pistons (2 , 3) and advantageously against the external face (2a) of the lower piston (2).
• a dip tube (14) fixed to one of the pistons (2 , 3) and advantageously against the external face (2a) of the lower piston (2).
• the make-up chamber (11) is arranged at the end of one of the pistons (2, 3), advantageously the lower piston (2), it is attached to the external face (2a) of that -ci and is connected by means of circulation of the fluid (15) to a secondary enclosure (16) adjoining the external face (3a) of the other piston (3).
• the dip tube (14) comprises at its lower end the low fixing point (17) of the shock absorber and forms with the pistons (2, 3) and their rod ( 4) a sub-assembly movable relative to the damper body (6) which carries at its upper end the top fixing point (18) of the damper (1). It is important to note that the sliding of the upper piston (3) in the body (6) requires an imperfect seal but controlled or organized to allow the purging of the chambers (9). The damping fluid (10) which escapes from the upper working chamber (9) along the piston (3) is brought back into the make-up enclosure (11) by the circulation means (15).
• circulation means (15) are advantageously formed by the bore (19) of the rod (4) and of the pistons (2, 3) which thus allows the fluid (10) to pass from the secondary enclosure (16) to the make-up enclosure.
• the damper (1) with a longitudinal axis (ZZ ') is in a vertical or inclined position, the fluid (10) advantageously formed by oil joins the make-up chamber (11) by gravity. It goes without saying that one would not go outside the protective field of the invention by making the circulation means connecting the two speakers differently.
• the guide means (20) and the segment (21) of the upper piston (3) are produced so as to allow the fluid (10) to leak along the piston (3) towards the secondary enclosure ( 16) to allow purging and to avoid any overpressure in the damper due to hydrodynamic phenomena. These leaks are then brought back thanks to the circulation means (15) to the make-up enclosure (11) to allow the work chambers (8, 9) and the rolling means (ML) to be replenished.
• the damper body (6) is formed by two tube portions (6a, 6b), an upper cylinder portion (6b) and a lower tube portion (6a ) which extend on either side of the intermediate partition (7).
• the lower tube portion (6a) has at its lower end the guide (22) and sealing (23) means which guide and seal the plunger tube (14) in its movement relative to to the lower tube portion (6a) of the body (6).
• the internal diameter of the upper cylinder portion (6b) and the external diameter of the dip tube (14) are advantageously identical so that the variation in the volumes of the working chambers (8, 9) is also compensated during the movement of the pistons (2, 3).
• the working chambers could be of different displacement within the limit of the possibilities of evacuation of the damping fluid by internal leaks organized for example at the level of the upper piston (3) and within the limit of possibilities of recharging the recharging means (12, 13).
• the make-up means are produced by a make-up valve (13) and a supply pipe or tube (12) connecting the lower working chamber (8) and the make-up enclosure. (11) to allow the working chamber (8) to be filled with the fluid (10) contained in the enclosure (11).
• the enclosure (11) comprises a fluid reserve (10), the level of which is permanently located above the orifice (24) of the supply duct (12) in order to avoid the introduction gas in the working chambers, which would modify the homogeneity and compressibility of the fluid and would alter the performance of the shock absorber.
• the rolling means (ML) are arranged perpendicular to the level of the intermediate partition (7) and are schematically illustrated by two unidirectional valves (25, 26) mounted in opposite directions and allowing different damping characteristics in compression and in extension and two rolling throttles, a first so-called compression valve (25) which allows the rolling of the fluid (10) from the lower chamber (8) to the upper chamber (9) and an extension valve (26) which allows rolling back from the upper chamber (9) to the lower chamber (8).
• These valves can be of the conventional type or have adjustment means to allow adaptation of the characteristics of the damper in compression or in extension. It may be noted that the transverse angular position of the partition (7) relative to the upper attachment (18) is adjustable by pivoting in order to make the different rolling settings accessible.
• the rolling means (ML) are formed by rolling channels and valves (216, 217) disposed directly in the intermediate partition (7).
• the rolling means (ML) are no longer disposed at the level of the intermediate partition but distant from said partition.
• the damper body (6) and more particularly its upper part comprises two concentric tube portions (6c, 6d) which define with the upper tube portion (6b) two annular spaces or circulation channels (28a, 28b) intended to bring the damping fluid (10) from the working chambers (8, 9) to the rolling device (ML).
• the rolling device (ML) consists of an external rolling block (29) located at the upper end of the damper near the top fixing point (18).
• This block includes at least one rolling valve whose technical characteristics can be adjusted by adjustment means (MR) such as adjustment screws (50) arranged perpendicularly to the body (6) of the damper (1).
• adjustment means such as adjustment screws (50) arranged perpendicularly to the body (6) of the damper (1).
• MR adjustment means
• adjustment screws (50) arranged perpendicularly to the body (6) of the damper (1).
• the transverse angular position of the rolling block (29) relative to the top or bottom fixing point (17, 18) of the damper (1) is adjustable thanks to the construction of the damper, the block ( 29) or the fixing point (18) which can be pivotally adjusted around the shock absorber (1) in order to promote accessibility to the adjustment screws (50) once the shock absorber is installed on a vehicle.
• the shock absorber (1) comprises an extension stop (30, 40) intended to accompany the end of extension stroke of the shock absorber.
• a screw (31) forming the extension stop is fixed to the upper fixing point (18), this stop is provided with elastic means (32) limited in their movement by sockets (33, 34) and interposed between a projection (35) of the nut of the upper piston (3) and the head (36) of the screw.
• the rolling takes place in a block (29) through which the oil is conveyed through the annular spaces (28a, 28b) left between the tubes and the cylinder.
• the rolling block (29) is free to rotate about the axis of the shock absorber so as to be angularly positioned so as to allow said block to be oriented radially as a function of the accessibility needs of the adjustments (50). Once the shock absorber is under pressure, the O-rings lock the said block in position.
• the spring (47) of the extension stop (40) is contained in an annular chamber (41) determined by a sheath (42) located inside the hollow rod (4).
• This sleeve is sealed in its lower part by the rod (4) and in its upper part by a sleeve (43).
• the sheath has a projection (44) inwards so that the head of the stop screw (36) comes to rest on it when the travel of the extension stop begins to act.
• the upper part (45) of the projection (44) of the sheath comes into contact with the projection (35) of the nut (48) of the piston (3), thus preventing the spring (47) from come to contiguous turns and determining a precise length of the shock absorber in the extended position.
• the annular chamber (41) is supplied with oil by the pressure generated during the extension stroke in the chamber (9) via a small groove (49) formed between the piston (3) and the rod (4), by the play of the thread between the nut (48) and the rod (4) then by the clearance between the bush (43) and the rod (4).
• the oil level in the chamber (41) is limited by a small orifice (59), the compression movements of the damper pushing the gas from the chamber (60) towards the chamber (41) and the extension movements from the damper sucking the overflow of oil from the chamber (41) to the chamber (60) through the orifice (59).
• the faces (36, 44) come into contact and the chamber (41) is reduced at the same time as the spring (47) settles and plunges into the oil, raising the level of the latter.
• the volume of the chamber (41) compresses, reinforces the effect of the spring (47) and the oil escapes through the orifice (59) constituting a hydropneumatic stop.
• the damper (1) may include a pressurizing device such as that illustrated diagrammatically in the second embodiment of FIG. 4.
• the pressurized damper is connected to a variable volume accumulator (151) by a conduit (152) and a valve (153) isolates the damper from the accumulator.
• a valve (154) inflates the accumulator and the shock absorber.
• the lower head of the shock absorber is made up of a plug (156) tightly traversed by an actuator rod (157) bearing at one of its ends the shock absorber fixing system and at the other end a piston (158).
• the piston (158) slides in leaktight manner in a blind cylinder (159) which is fixed to the plug (156).
• the volume (160) between the piston (158) and the bottom of the blind cylinder (159) is in communication with an external control cylinder (161) through the channels (162).
• the annular chamber (163) between the rod (157) and the blind cylinder (159) is, in its lower part, in communication with the interior of the damper by an orifice, for example a groove (164) intended to brake the passage of oil and by a valve (165) which allows free passage to this annular chamber.
• the oil reserve contained in the bottom of the shock absorber works like a pressurized accumulator which could possibly find its source in a separate cylinder.
• the pressurized oil contained in the lower part of the damper returns to the annular chamber (163) via the valve (165) this pressure acting in the annular chamber allows the rod (157) to enter the shock absorber.
• the inertia of the unsprung part sometimes tends to lengthen the damper, in this case the orifice (164) prevents the oil from rapidly escaping from the chamber (163) and prevents cavitation of the volume (160).
• the damper (1) comprises a body formed by a cylinder (6) in which two slide pistons (2) and (3) connected together by a hollow rod (4) which serves as a communication channel between the external faces of the two pistons as well as additional volume. Fixed in the cylinder and crossed by the rod (4), a partition (7) is inserted between the two pistons, thus determining two working chambers (8) and (9). This partition is provided with valves and compression lamination devices (216) and valves and extension lamination devices (217).
• An external rod (207) connects the piston assembly (2, 3), rod (4) to the lower fixing (17) of the shock absorber.
• the seal between this external rod (207) and the cylinder (6) is produced by a rolling bellows or accordion (211) thus leaving a make-up enclosure (11) in communication with the volume (250) via the rod (4) and the channels (266, 267, 268).
• Volumes (8), (9) and (11) are completely filled with oil.
• the internal volume of the rod communicates directly with the volume (250) and its minimum oil level is located at the bottom of the rod (4).
• the volume (250) is connected to atmospheric pressure by an orifice (221) containing an element preventing oil from leaving the shock absorber in the event of accidental overturning. If the damper is hermetically closed, the volume (250) must be large enough not to disturb the operation of the bellows (211).
• the lower piston (2) is provided with a make-up valve (13) and its duct (12) allowing oil to pass only from the chamber (11) to the lower chamber (8) and a relative seal (270) allowing the use of seals without friction which does not disturb the sliding between the piston and the cylinder.
• the leakage rate added by the two pistons is lower than the possibilities of re-supplying the valve (13). Guiding is carried out by the pistons and their segments, the contact between the rod (4) and the partition (7) only has a sealing role for which an imperfection can be tolerated in order to further improve the sliding qualities of the 'damper. This contact can be made by a floating segment (271) in order to eliminate the concentricity constraints. Possible leaks due to the relative tightness (270) of the lower piston (2) is compensated for during the following extension stroke.
• shock absorber is particularly intended for competition machines but can be declined in a very economical and simple version as illustrated in figure 5, for tourism use.
• the rolling system can be arranged concentrically, parallel, transversely, inclined or distant from the shock absorber and connected to the latter by conduits, it can be controlled manually or automatically, controlled by mechanical, hydraulic or electrical means.
• the laminating means can be adapted by interchangeability of preset cartridges containing the laminating systems and coming to be fixed in corresponding housings.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Fluid-Damping Devices (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=8847744

Family Applications (1)

Country Status (4)

Families Citing this family (1)

Family Cites Families (7)

• 2000
  • 2000-03-06 FR FR0002828A patent/FR2805871B1/fr not_active Expired - Fee Related
• 2001
  • 2001-03-05 AU AU4076501A patent/AU4076501A/xx active Pending
  • 2001-03-05 EP EP01911843A patent/EP1409890A1/de not_active Withdrawn
  • 2001-03-05 WO PCT/FR2001/000640 patent/WO2001066968A1/fr not_active Application Discontinuation

Non-Patent Citations (1)

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