FR2811390A1 - Damping assembly for rear wheel of motorcycle comprises regulator controlling the fluid flow, controlled by a calculator, which processes shocks signals from the front wheel - Google Patents

Abstract

The damping assembly comprises a plunger (1) sliding along a cylinder (5) and a regulator (2) in communication with both the cylinder and a fluid tank (3). The regulator is controlled by a calculator, which processes signals from the front wheel corresponding to the number and characteristics of the shocks absorbed.

Description

-1 - The present invention relates to an oil shock absorber for a vehicle,

especially

for a two-wheeled vehicle.

  We know oil shock absorbers adjustable compression and extension, which

  optimize the absorption of shocks caused by road irregularities.

  A disadvantage of shock absorbers of this type is that their adjustment can only be made by dismantling, to access valves regulating the movement of the

fluid in their piston.

  However, in use, it appears that the adjustment of a shock absorber cannot be considered optimal in all circumstances, because it depends on the type of terrain on which

  moves the vehicle and the driving mode adopted.

  There is therefore a need for a damper adjustable in real time, that is to say

while the vehicle is running.

  The present invention aims to provide such a shock absorber.

  The damper according to the present invention comprises a piston having a movable rod, one end of which plunges into a cylinder containing an incompressible hydraulic fluid and is characterized in that it further comprises a fluid flow modulator, which communicates with the cylinder, and a hydraulic fluid reserve chamber, which communicates with the modulator and in which the hydraulic fluid is subjected to a high pressure, the modulator comprising two separate internal fluid circulation channels, one in the direction of the reserve chamber, The other in the direction of the piston, each channel being provided with an independent fluid flow adjustment member

  in said path, capable of being operated from outside the modulator.

  It is understood that the operation of the damper according to the invention can be easily optimized in real time by the driver of the vehicle acting directly on

  the two independent modulator flow adjustment members.

  Thanks to the independence of the two modulator channels, the driver can adjust

  the compression damper regardless of its extension setting.

  In particular, it is possible, thanks to the invention, to obtain a certain hardness of the shock absorber during compression, to prevent the suspension of the vehicle from reaching the end of its travel too quickly, while retaining great flexibility in extension, so that the shock absorber quickly returns to its maximum stroke position following an impact. Such an adjustment is particularly suitable for driving a vehicle with

two wheels in rough terrain.

  -2- In a particular embodiment of the invention, each channel of the modulator comprises a non-return valve which ensures the circulation of the hydraulic fluid only

in the desired direction.

  According to a particular characteristic of the invention, the flow control member is constituted by a hydraulic brake. According to another characteristic of the invention, the reserve chamber comprises two compartments separated by a sealed mobile piston, the first compartment being in communication with the piston cylinder through the modulator, the other

  compartment closed and containing gas under pressure.

  The gas pressure is advantageously around 25 bars.

  In a particular embodiment of the invention, the piston cylinder comprises a separating plate with valves which delimits two compartments in the cylinder, of which

  one is in communication with the reserve chamber through the modulator.

  Advantageously, the operation of the two modulator adjustment members is carried out using devices placed on the vehicle in a location that is easily

accessible by the driver.

  For example, if the shock absorber according to the invention equips a motorcycle, the adjustment devices are located on the upper triple clamp, which allows the motorcycle driver to intervene on the maneuvering devices and therefore to adjust the shock absorber

  compression and extension during vehicle evolution.

  It may be noted that, according to the invention, a spring can be used for the suspension, the setting pressure of which is lower than that commonly used, thanks to the presence of the reserve chamber which makes it possible to maintain the hydraulic fluid at a pressure

very high.

  Indeed, the gas which is kept under pressure in the reserve chamber fills

  an elastic organ function in addition to its fluid pressurizing function.

  The advantage of this characteristic of the invention is that a sudden hardness of the damping at the end of the spring stroke is avoided, since the gas can be compressed without any mechanical stop being reached, at the difference of a coil spring

  traditional whose turns can come to support two by two.

  Another advantage resulting from the fact that the gas present in the reserve chamber acts as an elastic member is that it is not necessary to dismantle the damper to adjust the hardness of the spring; it suffices to act on the pressure of the gas contained in the

reserve room.

  -3- Tests initiated by the inventor have shown that the shock absorber according to the invention makes it possible to obtain suspension movements much greater than those

  achieved with traditional shock absorbers.

  In addition, the center distance of the shock absorber according to the invention is much smaller than the center distance of a traditional shock absorber, which provides the additional advantage of allowing a lowering of the center of gravity of the vehicle and therefore contributing to

  improve the grip of the vehicle on the ground.

  In a particular embodiment, the shock absorber according to the invention equips the rear axle of the vehicle and its operating devices consist of an electronic control unit associated with a computer, itself connected to micro-sensors

  mounted on the front axle of the vehicle.

  In this embodiment, the shocks undergone by the front shock absorbers are measured by the micro-sensors and the computer determines the optimal adjustment of the rear shock absorbers for controlling the electronic control unit for the

modulator.

  In this way, the rear axle is optimally adjusted to absorb all the

  impacts previously suffered by the front axle.

  In order to facilitate understanding of the invention, we will now describe an embodiment provided by way of non-limiting example, with reference to the accompanying drawings in which: - Figure 1 shows sections of the various components of a shock absorber according to the invention,

  - Figure 2 is an enlarged view of part II of Figure 1.

  The shock absorber comprises three components, namely a piston 1, a modulator 2 and

a reserve room 3.

  The piston 1 consists of a movable rod 4 which evolves in a cylinder 5 filled with oil. The cylinder 5 is provided with a separating plate 6 with valves 7, well known in

this domain.

  The end 8 immersed in the oil of the rod 4 has an anti-ejection collar

  9 which limits the travel of the rod during the extension of the shock absorber.

  The lower anchor point 10 of the shock absorber is fixed to the swing arm provided for this

effect on the vehicle.

  The cylinder 5 is connected to the modulator 2 by a hydraulic hose 11 which terminates in a distribution chamber 12 internal to the modulator. This distribution chamber 12 has two ends 13,14 each provided with a non-return valve 15,16. One 15 of these valves (the one on the left in the figure) allows the passage of the fluid in a first channel 17 designated compression channel. The other non-return valve 16 authorizes the entry into the distribution chamber 12 of the fluid coming from a second channel 18 called

extension channel.

  The two channels 17, 18 constitute separate internal paths for the circulation of fluid.

  FIG. 2 shows the detail of the valve 15 and of the channel 17.

  The valve 15 is constituted by a ball 29 retained in a brass tube 30 engaged

  in force in the bore forming the distribution chamber 12.

  The tube 30 has a slot 31 allowing the fluid to enter the channel 17

  when the ball 29 moves back into the tube 30 under the pressure of the fluid.

  A channel 17a allows the fluid expelled by the ball during its retreat to evacuate towards

the reserve room.

  This channel 17a also ensures good application of the ball 29 against its seat formed by the shoulder 31 at the end of the tube 30 when the fluid circulates in

  direction of the cylinder, as will be described.

  The two channels 17,18 meet on the non visible side of the modulator, where a

  second hydraulic hose 19 connects the modulator 2 to the reserve chamber 3.

  As can be seen in the figure, the compression channel 17, like the extension channel 18 of the modulator, is equipped with a hydraulic brake 20,21 which, in the present case, is equipped with a screw jack 22,23 whose adjustment axially displaces a

  shutter 24.25 whose seat intercepts said channel 17.18.

  Thus, when the shutter 24.25 is applied against its seat, the channel 17.18 is almost completely closed. The flow of fluid in said channel is limited to its

  minimum, the shock absorber is made hard.

  On the contrary, when the shutter 24,25 is far from its seat, the fluid can easily circulate in the channel 17,18 and the damper is soft. He reacts very quickly

  to stresses resulting from shocks to the undercarriage.

  The reserve chamber 3 consists of a pressurized reservoir containing a sealed mobile piston 26, which separates the interior of the reservoir into a first compartment 27 containing the oil, compartment which is connected to the modulator 2 by the second hydraulic hose 19 previously described, and a second compartment 28 containing gas

under pressure.

  The operation of the damper according to the invention will now be described.

  When the undercarriage is impacted, the piston rod 4 sinks into the cylinder 5. The additional volume which it then occupies in the cylinder drives out a

  certain amount of oil in the hydraulic hose 11.

-5-

  Oil expelled from the cylinder enters modulator 2 and passes through the check valve.

  return 15 located on the left to engage in the compression channel 17. The flow of the

  fluid is fixed by the hydraulic brake 20, adjusted appropriately.

  The fluid is then led by the second hose 19 into the first compartment 27 of the reserve chamber 3. The gas under pressure in the second compartment 28 of the reserve chamber undergoes an increase in pressure and reacts like an elastic member by accumulating

  energy which will be restored when the shock absorber is extended.

  Immediately after the impact, the shock absorber relaxes under the combined effect of the suspension spring (not shown) and the compressed gas in the

  reserve 3 which expels the oil towards the modulator 2.

  The oil from the reserve chamber 3 reaches the modulator 2 and passes through the

extension channel 18.

  During this crossing, the oil flow is regulated by the hydraulic brake 21.

  The oil then passes through the right check valve 16, enters the chamber

  12 and returns to cylinder 5 using the first hose 11.

  We see that the damper according to the invention again provides a double effect

  technique consisting of a hardness adjustment and an elastic organ effect.

  The two hydraulic brakes 20,21 are adjusted independently of one of

  The other and can be insured by the driver of the vehicle when the vehicle is moving.

  The embodiment which has just been described does not have any limiting character of

  the scope of the invention, which is defined by the appended claims.

-6-

Claims (9)

  1. Damper comprising a piston (1) having a movable rod (4), one end of which (8) plunges into a cylinder (5) containing an incompressible hydraulic fluid, characterized in that it further comprises a fluid flow modulator (2) which communicates with the cylinder (5) and a reserve chamber (3) of hydraulic fluid which communicates with the modulator (2) and in which the hydraulic fluid is subjected to a high pressure, the modulator comprising two channels (17 , 18) separate internal fluid circulation, one in the direction of the reserve chamber (3), the other in the direction of the piston (1), each channel (17,18) being provided with a member (20 , 21) independent of fluid flow adjustment in said channel, capable of being operated from outside the modulator. 2. Damper according to claim 1, characterized in that each channel (17,18) of the modulator comprises a non-return valve (15,16) which ensures the circulation of the fluid   hydraulic only in the desired direction.   3. Shock absorber according to any one of claims 1 and 2, characterized in that   that each flow control member is constituted by a hydraulic brake (20,21).   4. Shock absorber according to any one of claims 1 to 3, characterized in that   that the reserve chamber (3) has two compartments (27,28) separated by a mobile piston (26) sealed, the first compartment (27) being in communication with the piston cylinder through the modulator, the other compartment being closed and containing a pressurized gas.   5. Shock absorber according to any one of claims 1 to 4, characterized in that   that the piston cylinder has a separating plate (6) with valves (7) which separates two compartments in the cylinder, one of which is in communication with the   reserve chamber (3) through the modulator (2).   6. Shock absorber according to any one of claims 1 to 5, characterized in that   that the operation of the two modulator adjustment members is carried out using devices placed on the vehicle in a location easily accessible to the driver. 7. Shock absorber according to claim 6, characterized in that it is mounted on a motorcycle and that the maneuvering devices are placed on the upper triple fork of the motorcycle.   8. Shock absorber according to any one of claims 1 to 7, characterized in that   that it equips the rear axle of the vehicle and in that its operating devices consist of an electronic control unit associated with a computer itself   connected to micro-sensors mounted on the front axle of the vehicle. -7-   9. Shock absorber according to any one of claims 1 to 8, characterized in that   that the shocks to the front shock absorbers are measured by the microsensors and the computer determines the optimal setting of the rear shock absorbers to control the   electronic control unit for the modulator.