FR2991920A1 - DAMPER, IN PARTICULAR FOR BICYCLES, COMPRISING AN ANTI-PUMPING SYSTEM - Google Patents

Abstract

The invention relates to a shock absorber comprising a body (0), a piston which slides in said body (0), a liquid (5) which is displaced by the piston, two chambers (C1, C2) separated by at least one orifice ( 2) through which the liquid (5) must pass when the piston (1) sinks into the body (0), a valve (3) movable between a closed position and an opening position of said orifice to release the passage liquid (5) from the first chamber (C1) to the second chamber (C2) through the orifice (2), a return system (4a) applying a force to the valve (3), so that it is necessary to exert a force on the piston to increase the pressure in the liquid (5) of the first chamber (C1) and to move the valve (3) from the closed position to the open position, the return system (4a ) having a delay device arranged to increase the return time of the valve (3) from the open position to the closed position s ous the effect of said return system and when the pressure in the first chamber (C1) equilibrates with the pressure in the second chamber (C2).

Description

The invention relates to a damper for a vehicle, motorized or not, particularly for bikes and mountain bikes. On mountain bikes, the front and rear suspensions make it possible to increase the cyclist's comfort and the grip of the wheels on the ground, especially during traffic on rough terrain. Bicycles are known whose front and rear suspensions consist of a spring which can be pneumatic or metallic and an oil damper. The spring makes it possible to return the suspension to its initial position after a shock and the shock absorber makes it possible to absorb the energy of the shock to prevent the suspension from oscillating. This type of suspension is not entirely satisfactory, in that it causes a pumping effect which results in a cyclic depression of said suspension, in particular under the action of a pedal stroke or when the cyclist is standing on the pedals, even when the ground is perfectly leveled, which causes the dissipation in the damper of a portion of the engine torque provided by said cyclist.

To overcome this drawback, we know including bikes including a suspension, including the rear suspension, has a damper which includes a manual locking lever, to allow the cyclist to disable said suspension.

However, this type of rear suspension requires the attention of the cyclist permanently to know whether to activate or deactivate said suspension. This becomes especially problematic when the cyclist is making an intense effort and is less lucid, or when said cyclist is on a path or a road that already requires great attention for the steering of the bike. To overcome this drawback, suspensions are known including the damper is arranged so that its damping coefficient allows to remove the pumping phenomenon, but said damper remains active on shocks. Indeed, the pumping is characterized in that a low force is applied to the suspension for a long time, while the shocks involve a great force for a very short time. The force that applies to the suspension applies in part to the damper of said suspension and results in a pressure in the oil of said damper. For this purpose, the damper comprises a piston which has an orifice through which the oil must pass for said damper to move, and a valve which is pressed against said orifice by means of a spring preventing the oil from passing through. through said orifice. When the pressure of the oil is low, it does not allow valve to overcome the force of the spring and the oil can not pass through the orifice. When the pressure of the oil is high, it moves the valve despite the force of the spring and releases the passage for the oil through the orifice, the damper can move. Since pumping involves a small force on the damper, the pressure is low and therefore the oil can not pass through the orifice, so the damper is blocked. During a shock, the force and therefore the pressure are greater, the oil can therefore pass through the orifice, the damper moves and the shock is absorbed. However this type of solution greatly degrades comfort, because it takes a minimum pressure for the suspension to move and to keep the valve raised, and thus to maintain the passage of oil through the open port. This results in a force in the shock throughout the shock that is transmitted to the cyclist. In addition, the force that is created on the damper is repeated with each shock while generally, the shocks follow each other with a very short duration between each of them.

The invention aims to improve the prior art by proposing in particular a shock absorber for a bicycle or any other vehicle, motorized or not, said damper for satisfactorily eliminating the pumping effect while limiting the impact on comfort. For this purpose, the invention provides a damper comprising a body, a piston which slides in said body, a liquid which is displaced by the piston, two chambers which are separated by at least one orifice through which the liquid must pass when the piston sinks into the body, a valve movable between a closed position of the orifice and an opening position of said orifice to release the passage of the liquid from the first chamber to the second chamber through said orifice, said damper comprising in in addition to a return system applying a force on the valve, so that it is necessary to exert a force on the piston to increase the pressure in the liquid of the first chamber and move the valve from the closed position to the position of opening, the return system also having a delay device which is arranged to increase the return time of the valve from the open position to the closed position under the effect of the return system and when the pressure in the first chamber equilibrates with the pressure in the second chamber.

The increase of the return time of the valve makes it possible to reduce the pressure in the liquid and thus to increase the comfort. When the valve is in the closed position, the pumping phenomenon is eliminated. Preferably, the valve moves in a translational movement.

Preferably, the return system may consist of a spring or an elastomer. In particular, the return system comprises a defusing device arranged to constrain the valve to move from the closed position to the open position.

In particular, the defusing device comprises a ferromagnetic portion disposed on the valve, and an electromagnet arranged to create a command force on the ferromagnetic portion to move the valve from the closed position to the open position .

In particular, the delay device exerts a braking force which slows down the return of the valve towards the closed position. In particular, the braking force is adjustable.

In particular, according to a first embodiment of the invention, the delay device comprises a piston laminating oil and having a first passageway through which the oil passes when the valve moves from the closed position to the opening position, and a second passageway smaller than the first passageway and through which the oil passes when the valve returns from the open position to the closed position. In particular, the first passageway is made by a hole which is obstructed by a washer, said washer being pressed against the piston by a spring. In particular, the piston slides in a tube containing the oil, the second passageway being formed by a gap formed between the piston and the tube.

In particular, the second passageway is made by a hole which is obstructed by a washer, said washer being pressed against the piston by a spring.

In particular, the delay device is arranged to retain during a release period the valve in the open position before it returns to the closed position.

In particular, the duration of unlocking is adjustable. In particular, according to a second embodiment, the delay device comprises a groove, a lug which slides in the groove, the groove and the valve being arranged in such a way that when the valve moves from the closed position to the opening position, the lug slides in the groove and that when the valve returns from the open position to the closed position, the lug abuts on an appendage formed on the groove, the lug being dislodged from the appendage by rotation relative to the throat.

In particular, the lug is integral with the valve and the groove is oblique so that the translation of the valve is coupled with its rotation, a motor acting on the rotation of the valve via a drive system to perform the rotation of the lug relative to the groove to dislodge said lug from the appendix. In particular, the motor comprises an angular position sensor, the rotation of the motor being controlled after the angular position sensor has located the positioning of the pin on the appendix and the unlocking time has elapsed. In particular, the motor can be controlled in the direction of movement of the valve from the closed position to the open position until the pin is housed in the appendix. In particular, the motor can be controlled by a controller, preferably electronic, which takes into account the information of the angular position sensor to act on said motor. In particular, according to a third embodiment, the delay device comprises a pawl positioned so as to allow the valve to pass during its movement from the closed position to the open position and to block the return of the valve from the position. in the closed position, a displacement sensor which marks the movement of the valve and an actuator which acts on the pawl to release the valve after the displacement sensor has detected a movement of said valve and the duration of unlocking has passed.

In particular, the actuator can be controlled by a controller, preferably electronic, which takes into account the information of the displacement sensor to act on the actuator. In the second and third embodiments, the deblocking duration is preferably of the order of a few seconds. In particular, experimental studies show that a deblocking duration between 1 and 5 seconds, and in particular 2 seconds, can be sufficient. In particular, in the second and third embodiments, the unblocking duration can be adjustable. This can be done either by means of a separate microprocessor, or by means of the motor controller or the actuator controller. Whatever the embodiment, the liquid of the damper may be oil, mineral or vegetable. Whatever the embodiment, the bicycle damper may comprise a return system allowing the liquid to pass from the second chamber to the first chamber. In particular, the return system consists of holes which are obstructed by a washer or a valve, said washer or said valve being held (e) by a spring to block the liquid when it moves from the first chamber to the second chamber . Other features and advantages of the invention will become apparent from the description which follows, made with reference to the appended figures, in which: FIGS. 1a and 1b show schematically a damper as described in the state of the invention; art, respectively in a static position (Figure la) and in motion (Figure lb); - Figure 2 schematically shows another embodiment of a damper as described in the state of the art in a static position; - Figure 3 schematically shows a damper according to one embodiment of the invention; - Figure 4 shows the damper of Figure 3 which is added a means of unlocking the suspension in a controlled manner; - Figures 5a and 5b show schematically a damper according to a second embodiment of the invention; - Figures 6a and 6b show a damper according to a third embodiment of the invention.

In connection with these figures, there is described below a vehicle comprising a suspension, said suspension comprising a metal or pneumatic spring and a hydraulic damper. The hydraulic damper comprises a body 0 and a movable piston 1 which can move inside the body 0 and push the oil 5 which is inside the body O. The oil 5 being incompressible, it must pass through an orifice 2. A valve 3 is obstructing the orifice 2 by being plated on said orifice by a spring 4a. When a force Fa is applied to the movable piston 1, the pressure in the oil 5 increases. This pressure is applied to the valve 3 and opposes the force created by the spring 4a on said valve. Figures 1a and 1b show a damper as described in the state of the art in a configuration where the orifice 2 is fixed relative to the body O.

FIG. 1a shows the damper in a configuration where the force Fa, and therefore the pressure in the oil 5, is not sufficient for the valve 3 to rise and let the oil pass through the orifice 2. In this case, there is no movement of the piston 1 with respect to the body O. The valve 3 is in the closed position of the orifice 2. FIG. 1b represents the damper in a configuration where the force Fa, and therefore the pressure in the oil 5, is sufficient for the valve 3 to move a distance dl with respect to the orifice 2 and let the oil pass through said orifice. The piston 1 can then move relative to the body 0 with a speed Viti. The valve 3 is in the open position of the orifice 2.

FIG. 2 shows a shock absorber such as can be found in the state of the art, in a configuration where the valve 3 is integral with the piston 1. A floating piston 36 separates from a chamber 35 where there is a compressible gas. The force Fa and therefore the pressure in the oil 5 is not sufficient for the valve 3 to rise and let the oil pass through the orifice 2. In this case, there is no movement of the oil. piston 1 relative to the body O. The valve 3 is in the closed position of the orifice 2. Figure 3 shows a damper according to one embodiment of the invention. The body 0 comprises a piston (not shown) and contains oil 5 which is displaced by said piston as said piston slides in said body. A separator 9 stationary relative to the body 0 separates a first chamber C1 which is located below said separator and a second chamber C2 which is located above said separator when the suspension is mounted on a bicycle in the operating configuration. The separator 9 has an orifice 2 for the passage of the oil 5, the damper comprising a movable valve 3, in particular in a translation movement, between a closed position and an open position of said orifice. A seal 13 prevents the oil 5 from passing between the body 0 and the separator 9. A return system consisting of a spring 4a plates the valve 3 on the separator 9 in the closed position of the orifice 2. The spring 4a is held at its other end by a support 12 which is fixed relative to a tube 8 mounted in the body 0 being fixed to said separator.

The damper also has a timing device which is arranged to increase the return time of the valve 3 from the open position to the closed position under the effect of the return system 4a and when the pressure in the first chamber Cl equilibrates with the pressure in the second chamber C2. In particular, the delay device exerts a braking force which slows the return of the valve 3 to the closed position, said braking force being able to be adjustable in particular.

To do this, in connection with FIG. 3, the delay device comprises a piston 21 which is integral with the valve 3 and which can slide in the tube 8, said piston rolling oil 22 which is contained inside the tube 8 between the support 12 and a wall 19. The wall 19 is locked in translation relative to the tube 8 by means of circlips 20. The volume located between the piston 21 and the wall 19 forms a third chamber C3, the volume located between the piston 21 and the support 12 form a fourth chamber C4. The piston 21 has a first passageway allowing the oil 22 to pass from the third chamber C3 to the fourth chamber C4 when the valve 3 moves from the closed position to the open position, and a second passageway allowing the oil 22 to pass from the fourth chamber C4 to the third chamber C3 when the valve 3 returns from the open position to the closed position.

The first passageway is formed by at least one hole 23 formed in the piston 21, said hole being obstructed by a washer 18 which is pressed onto the piston 21 by a spring 17. In connection with FIG. 3, two holes 23 are provided. on the piston 21. Furthermore, the second end of the spring 17 is retained by a circlip 16 which is fixed on the piston 21. In addition, the second passageway is formed by a gap 24 formed between the piston 21 and the tube 8.

When the valve 3 moves upwards, that is to say from the closed position to the open position, the oil 22 pushes the washer 18 and can pass both through the holes 23 and through the gap 24. The holes 23 are dimensioned so that the rolling of the oil 22 does not oppose the movement of the piston 21. When the valve 3 moves downwards, that is to say from the opening position towards the closed position, the washer 18 prevents the oil 22 to pass through the holes 23 and it can only pass through the gap 24.

In particular, the second passageway is smaller than the first passageway. To do this, the gap 24 is dimensioned so that its surface is smaller than that of the holes 23 and the rolling of the oil 22 slows the movement of the piston 21.

When the pressure of the oil 5 in the first chamber Cl increases and that it pushes the valve 3 sufficiently so that it moves upwards and to separate the separator 9 from the valve 3, the oil 5 can then move from the first chamber C1 to the second chamber C2. At the same time, the piston 21 moves upwards and the oil 22 passes from the third chamber C3 to the fourth chamber C4 without resistance. The oil 5 can pass from the inside of the tube 8 to the space between the tube 8 and the body 0 through a hole 14 formed on said tube. The spring 4a makes it possible to bring the valve 3 back into contact with the separator 9, the valve 3 and the piston 21 are slowed down by the rolling of the oil 22 during the passage from the fourth chamber C4 to the third chamber C3. To allow the return of the oil 5 of the second chamber C2 to the first chamber C1, a return system is provided on the separator 9. The separator 9 is provided with holes 15 which are obstructed by a washer 7 held by a spring 11. The spring 11 is held at its other end by a nut 10. The washer assembly 7 - spring 11 allows the passage of the oil 5 that the second chamber C2 to the first chamber Cl. 2 99192 0 11 The FIG. 4 represents a damper with the same configuration as that represented in FIG. 3, and in which the return system 4a further comprises a defusing system arranged to constrain the valve 3 to move from the closed position to the position of FIG. 'opening. The defusing system comprises a ferromagnetic portion 34b disposed on the valve 3, and in particular on the piston rod 21. The defusing device further comprises an electromagnet 34a arranged to create a control force on the ferromagnetic portion 34b in order to lift the valve 3 and thus release the orifice 2 to unlock the damper. Figures 5a and 5b show a damper according to another embodiment of the invention. The body 0 comprises a piston (not shown) and contains oil 5 which is displaced by said piston as said piston slides in said body. A separator 9 stationary relative to the body 0 has openings 2 for the passage of the oil 5, the damper comprising a movable valve 3, in particular in a translational movement, between a closed position and an open position said orifices. A seal 13 prevents the oil 5 from passing between the body 0 and the separator 9. A return system consisting of a spring 4a plates the valve 3 on the separator 9 in the closed position of the orifices 2. The spring 4a is maintained at its other end by the support 12 which is fixed relative to the tube 8. The valve 3 is guided by a guide 25 which is fixed relative to the separator 9. Moreover, in this embodiment, the delay device is 25 arranged to retain during a release time the valve 3 in the open position before it returns to the closed position. In particular, the duration of unlocking can be adjustable. To do this, the delay device comprises a lug 26 integral with the valve 3 and which slides in a groove 27 provided on the guide 25. The groove 27 comprises an upper part inclined at an angle Alpha relative to the vertical and a part lower vertical. The valve 3 must therefore move simultaneously in vertical translation and in rotation on the upper part, then only in vertical translation on the lower part. The groove 27 also has an appendix 28 which is located at the junction of the two parts of the groove 27. A motor 29 is connected by a drive system 40 to the valve 3 and can make it possible to turn the valve 3. In the case where the motor 29 is not powered, it has no influence on the rotation of the valve 3. An angular position sensor 32a integrated in the motor 29 allows to know the angular position of the valve 3, and in particular the positioning of the lug 26 in the groove 27. When the pressure of the oil 5 in the part below the separator 9 increases and pushes the valve 3 sufficiently to exceed the force created by the spring 4a, the oil 5 can pass from the first chamber C1 to the second chamber C2. The oil 5 can pass from the inside of the tube 8 to the space between the tube 8 and the body 0 through the hole 14. Thus, the valve 3 moves from the closed position to the open position. When the valve 3 is sufficiently raised, the lug 26 arrives in the oblique upper part of the groove 27.

During the return of the valve 3 in contact with the separator 9, that is to say when said valve returns from the open position to the closed position, said valve moves helically through the displacement of the pin 26 in the oblique upper part of the groove 27, then said lug abuts on the appendage 28 of the groove 27. In order for the lug 26 to be dislodged from the appendage 28 and engages in the first oblique part of the groove 27, it is necessary for the motor 29 to turn the valve 3 in order to drive said pin in rotation with respect to the groove 27. In particular, the rotation of the motor 29 can be controlled after the angular position sensor 32a has detected the positioning of the the lug 26 on the appendix 28 and that the duration of unlocking has elapsed. To do this, the motor 29 can be controlled by a controller (not shown), preferably electronic, which takes into account the information of the angular position sensor 32a to act on the motor 29. In addition, the sensor 32a makes it possible to locate the moment when the lug 26 is in the lower vertical part of the groove 27. Once the lug 26 is in the lower part of the groove 27, the spring 4a brings the valve 3 back into contact with the separator 9, so in the closed position. To allow the return of the oil 5 of the second chamber C2 to the first chamber C1, a return system is disposed on the separator 9. The separator 9 is provided with holes 15 which are obstructed by a washer 7 held by a spring 11. The spring 11 is held at its other end by a nut 10. The washer assembly 7 - spring 11 allows the passage of oil from the second chamber C2 to the first chamber Cl.

The motor 29 can also be controlled in the direction of the displacement of the valve 3 from the closed position to the open position in order to raise the valve 3 when it is in contact with the separator 9, and this until the lug 26 is housed in the appendix 28, as shown in Figure 5b.

In the embodiments described in FIGS. 3, 4, 5a and 5b, the tube 8 and the separator 9 are fixed with respect to the body 0. However, variants of these embodiments may be provided, in which the tube 8 and the separator 9 slide inside the body 0 as a piston.

Figures 6a and 6b show a damper according to another embodiment of the invention. The body 0 comprises a piston (not shown) and contains oil 5 which is displaced by said piston as said piston slides in said body. A separator 9, which is stationary relative to the body 0, separates a first chamber C1 which is located below said separator 9 and a second chamber C2 which is located above said separator 9 when the suspension is mounted on a bicycle. in operating configuration. The separator 9 has an orifice 2 for the passage of the oil 5, the damper comprising a valve 3 movable between a closed position and an open position of said orifice. A return system consisting of a spring 4a plates the valve 3 on the separator 9 in the closed position of the orifice 2. The spring 4a is held at its other end by the support 12 which is fixed relative to the tube 8. In this embodiment, the delay device comprises a pawl 31 which can pivot about an axis 31a fixedly mounted relative to the body 0 and provided with a torsion spring 31b, said device further comprising an actuator 33 enabling move the valve 3 and a displacement sensor 32 which indicates the movement of said valve. In particular, the pawl 31 is positioned so as to let the valve 3 during its movement from the closed position to the open position and to block the return of said valve from the open position to the closed position, in particular housing in a recess 30 formed on the valve 3. In connection with Figure 6b, when the valve 3 is raised due to the pressure of the oil 5 in the first chamber C1, the hollow 30 reaches, after a displacement The torsion spring 31b is made in such a way that the pawl 31 enters the recess 30, which prevents the valve 3 from coming into contact with the separator 9. The sensor 32 makes it possible to know from which moment the valve 3 is no longer in contact with the separator 9. After an unlocking period Ti after this instant, the actuator pivots the pawl 31 so as to pull it out of the recess 30 and let the valve 3 come into contact with the separator 9, as represented on the fi Figure 6a. In particular, the actuator 33 can be controlled by a controller (not shown), preferably electronic, which takes into account the information of the displacement sensor 32 to act on the actuator 33.

The suspension system described above can be used on any type of two-wheeled vehicle, for example: mountain bike, road bike, cyclo-cross bike, track bike, city bike, electric bike, motorcycle or other.

Claims (16)

REVENDICATIONS1. Shock absorber comprising a body (0), a piston which slides in said body (0), a liquid (5) which is displaced by the piston, two chambers (C1, C2) which are separated by at least one orifice (2) by the liquid (5) must pass when the piston is sinking into the body (0), a valve (3) movable between a closed position of the orifice (2) and an opening position of said orifice to release the passing the liquid (5) from the chamber (C1) to the chamber (C2) through said orifice, said damper further comprising a return system (4a) applying a force to the valve (3), so that it is necessary to exert a force on the piston to increase the pressure in the liquid (5) of the first chamber (C1) and to move the valve (3) from the closed position to the open position, said damper being characterized in that that the return system (4a) also has a delay device which is arranged to increase the temperature s return the valve (3) from the open position to the closed position under the effect of said return system and when the pressure in the first chamber (Cl) equilibrium with the pressure in the second chamber (C2 ). 2. Shock absorber according to claim 1, characterized in that the valve (3) moves in a translational movement between the closed and open positions. 3. Shock absorber according to claim 1 or 2, characterized in that the return system (4) comprises a defusing system arranged to constrain the valve (3) to move from the closed position to the open position. 4. Shock absorber according to claim 3, characterized in that the defusing device comprises a ferromagnetic part (34b) disposed on the valve (3), and an electromagnet (34a) arranged to create a force on the control part ferromagnetic (34b) to move the valve (3) from the closed position to the open position. 5. Damper according to any one of claims 1 to 4, characterized in that the delay device exerts a braking force which slows the return of the valve (3) to the closed position. Shock absorber according to Claim 5, characterized in that the braking force is adjustable. Shock absorber according to Claim 5 or 6, characterized in that the delay device comprises a piston (21) laminating oil (22) and having a first passageway through which the oil (22) passes when the valve (3) moves from the closed position to the open position, as well as a second passageway smaller than the first passageway and through which the oil (22) passes when the valve (3) returns from the open position to the closed position. 8. Damper according to claim 7, characterized in that the first passageway is formed by at least one hole (23) which is obstructed by a washer (18), said washer being pressed against the piston (21) by a spring (17). 9. Damper according to claim 7 or 8, characterized in that the piston (21) slides in a tube (8) containing the oil (22), the second passageway being formed by a gap (24) formed between the piston (21) and the tube (8). 10. Damper according to any one of claims 1 to 4, characterized in that the delay device is arranged to retain for a duration of unlocking the valve (3) in the open position before it returns to the position of closing. 11. Damper, according to claim 10, characterized in that the duration of unlocking is adjustable. Damper according to claim 10 or 11, characterized in that the delay device comprises a groove (27), a pin (26) which slides in the groove (27), the groove (27) and the valve (26). being arranged such that when the valve (3) moves from the closed position to the open position, the lug (26) slides in the groove (27) and when the valve (3) returns from the open position to the closed position, the lug (26) abuts an appendage (28) formed on the groove (27), the lug (26) being dislodged from the appendage (28) by rotation relative to the groove (27). 13. Shock absorber according to claim 12, characterized in that the lug (26) is integral with the valve (3) and that the groove (27) is partially oblique so that the translation of the valve (3) is coupled with its rotation, a motor (29) acting on the rotation of the valve (3) via a drive system (40) to effect the rotation of the lug (26) relative to the groove (27) to dislodge said lug (26) of Appendix (28). Shock absorber according to Claim 13, characterized in that the motor (29) comprises an angular position sensor (32a), the rotation of the motor (29) being controlled after the angular position sensor (32a) has located the positioning the lug (26) on the appendage (28) and that the unlocking time has elapsed. Damper according to Claim 13 or 14, characterized in that the motor (29) is controlled in the direction of movement of the valve (3) from the closed position to the open position until the pin (26) fits in the appendix (28). 16. Damper according to claim 10 or 11, characterized in that the delay device comprises a pawl (31) positioned so as to let the valve (3) during its movement from the closed position to the open position and to blocking the return of the valve (3) from the open position to the closed position, a displacement sensor (32) which indicates the movement of the valve (3) and an actuator (33) acting on the pawl (31) to release the valve (3) after the displacement sensor (32) has detected a displacement of said valve (3) and the unlocking time (Ti) has elapsed.