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
  • F16F9/32—Details
  • F16F9/50—Special means providing automatic damping adjustment, i.e. self-adjustment of damping by particular sliding movements of a valve element, other than flexions or displacement of valve discs; Special means providing self-adjustment of spring characteristics
  • F16F9/512—Means responsive to load action, i.e. static load on the damper or dynamic fluid pressure changes in the damper, e.g. due to changes in velocity
  • F16F9/5126—Piston, or piston-like valve elements
• • 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
  • F16F9/3214—Constructional features of pistons
• • 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
  • F16F9/34—Special valve constructions; Shape or construction of throttling passages
  • F16F9/3405—Throttling passages in or on piston body, e.g. slots
• • 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
  • F16F9/34—Special valve constructions; Shape or construction of throttling passages
  • F16F9/348—Throttling passages in the form of annular discs or other plate-like elements which may or may not have a spring action, operating in opposite directions or singly, e.g. annular discs positioned on top of the valve or piston body
  • F16F9/3481—Throttling passages in the form of annular discs or other plate-like elements which may or may not have a spring action, operating in opposite directions or singly, e.g. annular discs positioned on top of the valve or piston body characterised by shape or construction of throttling passages in piston

Definitions

• the present invention relates to a hydraulic shock absorber for the suspension of a motor vehicle, as well as a motor vehicle equipped with such a shock absorber.
• Motor vehicles have on each wheel a shock absorber arranged in parallel with a suspension spring, which brakes the movement of the suspension in order to ensure comfort and roadholding.
• Hydraulic shock absorbers often comprise a rod linked to a piston moving in a cylinder by delimiting two chambers, with a limitation of the passages of the fluid from one chamber to the other in order to slow down the movements of this rod.
• the braking intensity of the suspension movement represents a compromise responding to different constraints.
• shock absorbers comprise an inertial system comprising a column of fluid connecting the two chambers arranged on each side of the piston.
• the document FR3079275 describes a hydraulic motor vehicle suspension damper comprising a cylindrical body containing a piston fixed to a sliding axial rod, delimiting in this body two chambers which are connected by a column of inertial fluid.
• the inertial fluid column is formed inside of the axial rod. This avoids taking up a volume outside the body of the shock absorber to make the column and therefore limits the weight of the assembly.
• the invention aims to remedy these drawbacks effectively by proposing a motor vehicle suspension hydraulic damper comprising a body containing a main piston connected to a rod, said main piston being intended to slide inside the body, the body being intended to contain a damping fluid, said main piston dividing the body into a first chamber and a second chamber,
• said main piston comprising a first leak passage and a second leak passage placing the first chamber and the second chamber in fluid communication
• a compression piston arranged inside a first housing of the main piston being provided with a first fluid passage groove arranged opposite the first leakage passage in a rest position, said compression piston being able to sliding towards the rod of the main piston under the effect of a fluid pressure during a compression phase so as to offset the first fluid passage groove with respect to the first leakage passage in order to progressively close the first leakage passage , and
• an expansion piston arranged inside a second housing of the main piston being provided with a second fluid passage groove arranged opposite the second leakage passage when the expansion piston is in a rest position, said expansion piston being capable of sliding towards the rod of the main piston under the effect of a fluid pressure during an expansion phase so as to offset the second fluid passage groove with respect to the second leakage passage to gradually close the second leakage passage.
• the invention thus makes it possible, by varying the leakage of fluid from the shock absorber during a compression or expansion phase, to provide variable damping improving the comfort and control of the movements of the body. Fluid leakage is maximized at very low frequencies to optimize shock behavior at low travel, and progressively reduced to improve ride and roll behavior at higher travel.
• the invention has the advantage of being able to adapt to a wide range of vehicles and of having a limited cost.
• the compression piston is mounted on a return spring able to move the compression piston towards the rest position when the compression piston is no longer subjected to a fluid pressure generated by a phase compression.
• the expansion piston is mounted on a return spring able to move the expansion piston towards the rest position when the expansion piston is no longer subjected to a fluid pressure generated by a phase of relaxation.
• the rod comprises a cavity in fluid communication with the first chamber.
• the cavity of the rod is in fluid communication with a volume of the first housing of the compression piston and with a volume of the second housing of the expansion piston.
• a seal is arranged between an outer periphery of the compression piston and an inner face of the first housing containing said compression piston.
• a seal is arranged between an outer periphery of the expansion piston and an internal face of the second housing containing said expansion piston.
• a non-return valve is arranged at one end of the first leakage passage associated with the compression piston, said non-return valve only allowing a passage of fluid from the first chamber to the second chamber during a compression phase and preventing a return of fluid from the second chamber to the first chamber during an expansion phase.
• a non-return valve is arranged at one end of the second leakage passage associated with the expansion piston, said non-return valve only allowing a passage of fluid from the second chamber to the first chamber and preventing a return of fluid from the first chamber to the second chamber during a compression phase.
• the invention also relates to a motor vehicle comprising a hydraulic shock absorber as previously defined.
• Figure 1 is a sectional view of a hydraulic shock absorber for a motor vehicle according to the present invention
• Figure 2 is a sectional view illustrating the fluid leaks in a compression phase and in an expansion phase of the hydraulic damper according to the present invention
• FIG. 3a is a view in partial section of the hydraulic damper according to the invention illustrating a maximum leakage passage on the side of a compression piston when the latter is in the rest position;
• Figure 3b is a partial sectional view illustrating a minimum leakage passage on the side of a compression piston when the latter has been moved radially inwards under the effect of pressure during a compression phase .
• Identical, similar or analogous elements retain the same reference from one figure to another.
• Figure 1 shows a hydraulic shock absorber 10 for the suspension of a motor vehicle in the rest or equilibrium position.
• the hydraulic damper 10 comprises a body 11, in particular of cylindrical shape, containing a main piston 12 intended to slide inside the body 11.
• the main piston 12 is connected to a rod 13.
• the body 11 contains a fluid of damper 10, such as oil for example.
• the main piston 12 hermetically divides the body 11 into a first chamber 15 and a second chamber 16.
• the body 11 of the shock absorber 10 can be fixed to the body of the vehicle, while the rod 13 can be fixed to an element of the suspension. Alternatively, the configuration of the bindings can be reversed.
• the damper 10, which is shown in the figures in a vertical position, can however assume any desired inclination inside the motor vehicle.
• the main piston 12 comprises a first leakage passage 19 and a second leakage passage 20 putting the first chamber 15 and the second chamber 16 in fluid communication.
• the rod 13 comprises a cavity 21 in fluid communication with the first chamber 16 of the damper 10 via a channel 22 formed in the rod 13. A balanced static pressure is thus obtained between the fluid of the cavity 21 and the fluid of the first room 15.
• a compression piston 23 is disposed inside a first housing 24 of the main piston 12.
• a seal 25 is disposed between an outer periphery of the compression piston 23 and an internal face of the first housing 24 containing said compression piston 23.
• the compression piston 23 hermetically divides the first housing 24 between a first volume 26.1 in fluid communication with the cavity 21 of the rod 13 and a second volume 26.2 in fluid communication with the second chamber 16.
• a channel 27 makes it possible to create a calibrated leak of fluid from the first volume 26.1 to the cavity 21 when the compression piston 23 moves towards the rod 13 of the main piston 12.
• the compression piston 23 is provided with a fluid passage groove 28 intended to be arranged facing the first leakage passage 19, when the compression piston 23 is in a rest position.
• the compression piston 23 is able to slide radially towards the rod 13 of the main piston 12 under the effect of fluid pressure during a compression phase so as to gradually close the first leak passage 19.
• the compression piston 23 is mounted on a return spring 30 able to move the compression piston 23 towards the rest position when the compression piston 23 is no longer subjected to a fluid pressure generated by a compression phase.
• An expansion piston 31 is disposed inside a second housing 32 of the main piston 12.
• a seal 33 is disposed between an outer periphery of the expansion piston 31 and an internal face of the second housing 32 containing said piston relaxing 31 .
• the expansion piston 31 hermetically divides the housing between a first volume 34.1 in fluid communication with the cavity 21 of the rod 13 and a second volume 34.2 in fluid communication with the first chamber 16.
• a channel 35 makes it possible to create a calibrated leak of fluid from the first volume 34.1 towards the cavity 21 when the expansion piston 31 moves towards the rod 13 of the main piston 12.
• the expansion piston 31 is provided with a fluid passage groove 37 intended to be arranged opposite the second leakage passage 20 when the trigger 31 is in a rest position.
• the expansion piston 31 is able to slide radially towards the rod 13 of the main piston 12 under the effect of a fluid pressure during an expansion phase so as to gradually close the second leakage passage 20.
• the expansion piston 31 is mounted on a return spring 38 capable of moving the expansion piston 31 towards the rest position when the expansion piston 31 is no longer subjected to a fluid pressure generated by an expansion phase.
• FIG. 3a illustrates thus a maximum leakage F1 for the compression piston 23 when the groove 28 of the latter is located opposite the first leakage passage 19.
• FIG. 3b thus shows a minimum leakage F1 when the compression piston 23 is at the end of its travel.
• the return spring 30 of the compression piston 23 is then compressed.
• the hydraulic fluid is compressed in the second chamber 16 and is under vacuum in the first chamber 15 of the body 11 .
• the expansion piston 31 moves radially towards the rod 13 and gradually enters the interior of the housing 32.
• the groove 37 of the expansion piston 31 shifts then relative to the second leak passage 20, so that the leak of fluid F2 from the second chamber 16 to the first chamber 15 is progressively reduced.
• the return spring 38 of the expansion piston 31 is then compressed.
• the return spring 38 of the expansion piston 31 will decompress during a subsequent compression phase.
• a non-return valve 39 is arranged at one end of the leakage passage 19 associated with the compression piston 23. This non-return valve 39 only allows a passage of fluid from the first chamber 15 to the second chamber 16 during a compression phase and prevents a return of fluid from the second chamber 16 to the first chamber 15 during an expansion phase.
• a check valve 40 is disposed at one end of the leakage passage associated with the expansion piston 31. This non-return valve 40 only allows a passage of fluid from the second chamber 16 to the first chamber 15 and prevents a return of fluid from the first chamber 15 to the second chamber 16 during a compression phase.

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

Applications Claiming Priority (2)

Publications (1)

Family

ID=77021620

Family Applications (1)

Country Status (3)

Family Cites Families (8)

• 2021
  • 2021-07-01 FR FR2107126A patent/FR3124837B1/fr active Active
• 2022
  • 2022-05-16 WO PCT/FR2022/050929 patent/WO2023275447A1/fr active Application Filing
  • 2022-05-16 EP EP22731736.9A patent/EP4363739A1/de active Pending

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