FR2828519A1 - Damping device assisting displacement of automobile door comprises piston in cylinder delimiting two chambers, piston activating circuit and piston hydraulic braking circuit - Google Patents

Abstract

The assistance device comprises a piston (13) in a cylinder (11) defining first (17) and second (18) chambers. A piston activating circuit sends fluid to one of the two sides of the piston and there is a hydraulic braking circuit (40) for the displacement of the piston. A spring loaded valve neutralizes the braking pressure in the first chamber at the end of piston travel in the door closed position and calibrated fluid passages increase a specified braking pressure in the second chamber at the end of piston travel in the door maximum opening position. A spring (66) for controls the passage of the fluid in the second chamber before displacement of the piston and at the start of the door displacement from its maximum opening position. An Independent claim is included for an automobile door using the assistance device.

Description

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 The present invention relates to a device for assisting the movement of an opening element with respect to a chassis comprising an opening of a shape complementary to that of the opening element, as well as a motor vehicle equipped with such an assistance device.

 The operation of the openings, in particular of motor vehicles, of the swinging door type, must obey particular effects in order to comply with safety instructions, or simply to facilitate their use.

 However, the presence in the openings of a growing number of members such as side reinforcements, power windows, mirrors, airbags, speakers, weighs down these openings.

 So that the opening is not likely to escape the hand which operates it, either by the action of the wind, or by the effect of the inclination of the vehicle and its own weight, it is known to associate to the pivot hinges of this opening a system of notches which requires a certain effort for the setting in motion of said opening. This effort must be canceled as soon as the movement is started to make the maneuver easier.

 For this, one or two stops during the pivoting of the opening are obtained by notches made on a metal bar on which circulates a group of rollers integral with said opening and which abuts against one or two ramps obtained by deformation of the metal of the metal bar.

 As soon as the rollers have passed the ramp, their movement is done without any effort. Most often, the position of the first notch corresponds to a position of the opening which allows access with a minimum of lateral space, a second notch is provided in a position which corresponds substantially to half of the opening of the opening and a last notch acts as a stop in the maximum open position of said opening.

 Hydraulic shock absorbers are also known which comprise a piston equipped with two symmetrical valves arranged so as to open under the action of a determined pressure of the fluid, then which remain open under a very clearly lower continuous pressure.

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 These devices offer an effect comparable to the usual mechanical notches, with an infinity of position throughout the opening stroke.

 In general, the devices used until now do not allow the movement of the opening to be gradually damped and in some cases the rebounding effect when the opening reaches its position of maximum opening.

 The invention aims to obtain a device for assisting the movement of an opening leaf, overcoming the drawbacks of the state of the art.

 The subject of the invention is therefore a device for assisting the movement of an opening element with respect to a frame comprising an opening of shape complementary to that of the opening element, said device comprising: - a piston movable in a cylinder and determining in this cylinder a first and a second chamber, said piston being intended to be connected to the opening or to the chassis and said cylinder being intended to be connected to the chassis or to the opening, - a circuit for actuating the piston by sending d '' a fluid in one of the two chambers to move the opening between a closed position and an open position, and - a hydraulic braking circuit for the displacement of the piston in the cylinder, characterized in that it comprises - means for neutralizing the braking pressure in the first chamber at the end of the piston stroke in the closed position of the leaf, - means for increasing the pressure of f to a determined value reinforcement in the second chamber at the end of the piston stroke in the maximum opening position of the opening, and - means for controlling the passage of the fluid in the second chamber before the displacement of said piston and at the start of the displacement control opening from its maximum open position.

 According to other characteristics of the invention:

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 - The cylinder is closed at one of its ends by a first bottom and at the other of said ends by a second bottom, said bottoms each comprising a nozzle communicating with the corresponding chamber and connected to the other nozzle by a conduit provided a valve movable between an open position for communicating said nozzles and a closed position, - the means for neutralizing the braking pressure comprise a valve disposed in the first bottom and movable by a control member under the action of the piston between an opening position of the nozzle of the first bottom placing the first chamber in communication with the conduit and a position of closing said nozzle, - the means for increasing the braking pressure comprise, on the one hand, a sliding valve intended to be applied under the action of the piston against a seat of complementary shape formed in the second bottom to close a central orifice for flow t of the fluid between the second chamber and the braking circuit and, on the other hand, a first calibrated passage of the fluid between said second chamber and said second nozzle, - the means for increasing the braking pressure comprise a second calibrated passage fluid between the second chamber and the second nozzle and a spring calibrated at a determined force to maintain said valve applied against a seat formed at one end of said second passage until the pressure in the second chamber exceeds the calibration force of said spring, - the means for controlling the passage of the fluid are formed by a spring interposed between the valve and the piston.

 The invention also relates to a motor vehicle comprising at least one opening articulated on a chassis provided with an opening of shape complementary to that of the opening, between an open position and a closed position of the opening by relative to the chassis, characterized in that it comprises a device for assisting the movement of said opening as previously mentioned.

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 Other characteristics and advantages of the invention will become apparent during the description which follows, given solely by way of example and made with reference to the appended drawings, in which: - FIG. 1 is a schematic view in longitudinal section of an assistance device according to the invention installed on a leaf of the swing door type, - FIG. 2 is a schematic view in longitudinal section and on a larger scale of the assistance device according to the invention, - FIG. 3 is a schematic view in longitudinal section of the means for neutralizing the braking pressure of the assistance device according to the invention, - FIG. 4 is a schematic view in longitudinal section of the means for increasing the braking pressure of the assistance device according to the invention, - Figs. 5 to 9 are schematic views in longitudinal section showing the different operating phases of the assistance device according to the invention.

 The invention will be described below with reference to an opening hinged by a hinge relative to a frame having an opening of a shape complementary to that of the opening to receive the latter in the closed position. The opening comprises a locking member on the chassis in the closed position, which can be operated by a person.

 In a motor vehicle, the opening is formed by a front door or a rear door. Of course, the assistance device according to the invention can be provided on each door and it can also be provided on the tailgate of the motor vehicle or on the front cover of this motor vehicle or on its sunroof.

 In the embodiment shown in FIG. 1, the assistance device comprises a cylinder 11 connected to the opening 1 by a support 2 and a rod 12 connected to the chassis 3 of the motor vehicle by a support 4.

 As shown in Figs. 1 and 2, the cylinder 11 delimits an internal space in which is guided, along the longitudinal axis of the cylinder 11,

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 a piston 13 mounted movable parallel to this longitudinal axis and comprising a seal 14 for sealing a fluid against the interior wall of the cylinder 11. This cylinder 11 is closed at one of its ends by a first bottom 15 and at other of said ends by a second bottom 16.

 The piston 13 shares the internal space of the cylinder 11 in a first chamber 17 delimited by the piston 13, the cylinder 11 and the first bottom 15 and in a second chamber 18 delimited by the piston 13, the cylinder 1 and the second bottom 16 .

 The piston 13 is fixed to the longitudinal rod 12 passing through the said piston 13 and which is guided longitudinally in both directions in through holes 19 and 20 provided in the bottoms, respectively 15 and 16.

 The bottom 15 is extended outside the cylinder 11 by a longitudinal tube 21 for guiding the rod 12, fixed by one end to said bottom 15 and ending in a yoke 22 intended to be connected to the opening 1 by an axis hinge 22 mounted on the support 2.

 The rod 12 comprises, at its end projecting from the bottom 16, a yoke 23 for connection by an axis 24 of articulation with the support 4 secured to the chassis 3.

 As shown in FIG. 3, the bottom 15 comprises, inside the cylinder 11, a circular shoulder 25 forming a stop for the piston 13 and serving to delimit the longitudinal stroke of the latter inside the cylinder 11 in the closed position of the opening 1.

 Furthermore, the bottom 15 comprises a first nozzle 26 and a second nozzle 27 communicating with the first chamber 17 via an orifice 28 formed in the bottom 15.

 Similarly, the bottom 16 has a shoulder 29 directed towards the inside of the cylinder 11 and a first nozzle 30 and a second nozzle 31 communicating with the second chamber 18 via a central orifice 32 formed inside the shoulder 29 of the bottom 16.

 As shown in Fig. 2, the first nozzles 26 and 30 of the bottoms, respectively 15 and 16, are interconnected by a conduit 33 provided

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 a valve 34 movable between an open position for placing said nozzles 26 and 30 in communication with a closed position.

 The second nozzles 27 and 31 of the bottoms, respectively 15 and 16, are connected, on the one hand, by conduits respectively 35 and 36, to a hydraulic circuit, not shown, for actuating the piston 13 by sending a fluid towards one of the two sides of said piston 13 to move the opening 1 between the closed position and the open position and, on the other hand, by conduits, respectively 37 and 38, to a circuit designated by the reference general 40, for hydraulic braking of the displacement of the piston 13 in the cylinder 11.

 The hydraulic braking circuit 40 comprises a three-way valve 41 of the solenoid valve type and a braking module 42.

 This braking module 42 has a first access 43 connected to an inlet of the solenoid valve 41 and a second access 44 connected to the conduit 37.

 The first and second ports 43 and 44 are interconnected in the braking module 42 by first and second communication channels 45 and 46 in which are mounted first and second valves 47 and 48 capable of resting each in a fluid-tight manner on first and second seats 49 and 50 interposed on the first and second tracks 45 and 46 to block the passage of fluid between the first access 43 and the second access 44.

 The valves 47 and 48 each have a hollow part for housing a compression spring, respectively 51 and 52, for holding said valves 47 and 48 against the seats, respectively 49 and 50.

 The device for assisting the movement of the opening element 1 also comprises: - means for neutralizing the braking pressure in the first chamber 17 at the end of the stroke of the piston 13 in the closed position of the opening element 1, - means for increasing the braking pressure in a second chamber 18 to a determined value at the end of the piston stroke in the maximum opening position of this opening element 1, and

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 - Means for controlling the passage of the fluid in the second chamber 18 before the displacement of the piston 13 and at the start of the displacement of said opening 1 from its position of maximum opening.

 As shown in FIG. 3, the means for neutralizing the braking pressure comprise a valve 55 displaceable by a control member 56 projecting from the first chamber 17.

 The valve 55 and the control member 56 are movable in translation in a direction parallel to the longitudinal axis of the cylinder 11 in a bore 57 formed in the bottom 15. This valve 55 has an internal housing 58 in which is arranged a spring compression 59 whose first end is supported in the bottom of the housing 58 and whose second end is supported in the bottom of the bore 57. This compression spring 59 maintains the valve 55 in the closed position of the first nozzle 26 and the assembly formed by this valve 55 and its control member 56 is held in this position by a stop 60 formed in the bore 57.

 As shown in FIG. 4, the means for increasing the braking pressure comprise a valve 65 sliding and normally bearing on a stop 12a formed on the rod 12 by the action of a compression spring 66 disposed between the piston 13 and said valve 65.

 In the central orifice 32 is provided a seat 67 in the form of a cone and intended to receive the head 65a of the valve 65 which also has the form of a cone.

 The means for increasing the braking pressure also comprise a first calibrated passage 70 opening on one side into the second chamber 18 and on the other hand into a transverse passage 71 connecting the first nozzle 30 with the second nozzle 31 and in which also opens the central opening 32.

 The means for increasing the braking pressure also include a second calibrated passage 72, one end of which opens into the second chamber 18 and the other end of which opens into the transverse passage 71. The end of the second passage 72 opens into the passage transverse 71 is closed by a valve 73 kept applied against said

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 end by a spring 74 calibrated at a determined force to maintain said valve 73 applied against its seat until the pressure in the second chamber 18 exceeds the calibration force of said spring 74.

 The compression spring 66 interposed between the valve 65 and the piston 13 forms the means for controlling the passage of the fluid enters the second chamber 18 before the displacement of said piston 13, as will be seen later.

 Referring now to Figs. 5 to 9, we will describe the operation of the assistance device according to the invention.

 In Fig. 2, the current position of the solenoid valve 41 is shown during the movement of the opening leaf 1 and this solenoid valve 41 is arranged in such a way that the hydraulic fluid cannot circulate between the nozzles 27 and 31 only after having crossed the valves. 47 or 48, depending on the direction of operation of this opening 1.

 Thus, when a positive difference in fluid pressure greater than a threshold value determined as a function of the stiffness of the spring 51 and present between the first port 43 and the second port 44 of the braking module 42, the first valve 47 is constrained by the fluid pressure to move away from its seat 49 to allow the fluid to pass through the conduit 37 and consequently from the second chamber 18 via successively the central orifice 32, the conduit 38, the solenoid valve 41, of the first access 43 of the second access 44, of the conduit 37, of the second nozzle 27, in the first chamber 17 of the cylinder 11.

 Still in the position of the solenoid valve 41 shown in FIG. 2, when a positive difference in fluid position greater than a threshold value determined as a function of the stiffness of the spring 52 and present between the second port 44 and the first port 43, the valve 48 is forced to move away from its seat 50 to let the fluid pass through the communication path 46 from the second port 44 to the first port 43 and thus to let the fluid pass from the first chamber 17 into the second chamber 18, in the opposite direction to that mentioned previously, the valve 47 then being in the closed position.

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 In the position of the solenoid valve 41 shown in FIG. 5, the hydraulic fluid flows freely between the nozzles 27 and 31 through the conduits 37 and 38 without having to pass through the hydraulic braking circuit 40.

 In the position of each solenoid valve 34 and 41 shown in FIG. 6, the hydraulic fluid cannot circulate between the nozzles 27 and 31 as well as between the nozzles 26 and 30. This isolation allows operation as a drive cylinder by connecting the nozzles 27 and 31 to the hydraulic power circuit annexed by the conduits 35 and 36 thereby authorizing mechanical assistance to the movements of the opening 1 by the intervention of a pressurized fluid from an auxiliary generator group.

 When the door 1 comes close to its fully closed position, it is necessary to neutralize the braking action of the valves 47 and 48 of the hydraulic braking circuit 40 which would disturb the operation of the lock of said door 1.

 For this, the piston 13 arriving at the end of the stroke, as shown in FIG. 7, pushes the valve 55 against the compression spring 59, which has the effect of putting the first chamber 17 into communication with the first nozzle 26 and the conduit 33.

 The hydraulic fluid can therefore circulate freely between the first chamber 17 and the second chamber 18 of the cylinder 11, provided that the valve 34 is in the open position, without passing through the valves 47 and 48 of the hydraulic braking circuit 40, thus giving a total freedom of movement to the piston 13 which allows the opening of the opening 1.

 Conversely, when the opening 1 arrives in its maximum opening position, it must be able to dampen the end of this movement that the action of the wind or a slope can accelerate.

 As shown in FIG. 8, at the end of the stroke of the piston 13 in the position of maximum opening of the leaf 1, the sliding valve 65 comes to bear against the corresponding seat 67 and closes the communication of the second chamber 18 with the nozzle 31 ce which forces the fluid to be evacuated through the calibrated passage 70 whose diameter has been defined to create a pressure drop

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 intended to degrade the pressure which is established in the second chamber 18 which leads to the slowing down of the piston 13.

 The braking effect will be all the greater the higher the initial speed of this piston 13 which is favorable for the damping effect.

The pressure P generated by the flow speed V in the calibrated passage 70 is established by the formula:
P = 1/2 p V2 with p which is equal to the specific mass of the moving fluid.

 Thus, the pressure P, and therefore the braking force applied to the piston 13, is higher the higher the speed at the start of braking. In addition, this pressure changes progressively with speed to cancel out when the piston 13 stops, without however ever preventing it from reaching the extreme position.

 This self-adjusting effect provides additional quality to the damping function.

 Finally, this principle based on the complete degradation of the energy accumulated by the speed and the mass of the opening leaf 1 in motion brings another fundamental quality to this arrangement due to the total absence of elastic rebound which is the main defect. usual shock absorbers based on springs or rubber or other elastomer buffers which restore almost all of the accumulated energy.

 However, a strong wind or a strong inclination of the vehicle can cause a speed of the opening 1 leading, at the start of the damping, to a pressure level such that the construction of the device had to be strongly dimensioned.

 The second calibrated passage 72, normally closed by the valve 73 held against its seat by the compression spring 74, allows additional circulation of the fluid between the second chamber 18 and the nozzle 31 when the pressure reaches the maximum level chosen and determined by this compression spring 74.

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If the section of the second calibrated passage 72 is S (m2) and if the pressure level must be limited to P (Pascals), the calibration of the spring 74 is:
F (newtons) = S x P.

 As soon as the deceleration pressure reaches the value of P, the valve 73 frees the passage of the fluid which can flow towards the nozzle 31.

 This passage remains open until the piston speed has decreased sufficiently for the pressure generated to drop to a level below P.

 The valve 73 then closes and the end of the movement is obtained by the flow of the fluid through the single calibrated passage 70.

 Preferably, the cross section of the second calibrated passage 72 is larger than that of the first calibrated passage 70 to cope with a possibly and momentarily high fluid flow rate.

 The compression spring 74, by automatically modulating the position of the valve 73, defines the useful section for the outlet of the fluid, therefore its instantaneous speed which makes it possible to regulate the pressure of the fluid around the value P until the complete closure by the return of this valve 73 on its seat.

 The means for controlling the passage of the fluid in the second chamber 18 before the displacement of the piston 13 and at the start of the movement of the opening element 1 from its maximum open position are formed by the spring 66 disposed between the piston 13 and the valve sliding 65.

 Indeed, it is important to allow the reverse movement of the piston 13 without the annoying braking effect.

 For this and as shown in FIG. 9, the valve 65 moves away from its seat 67 as soon as a slight increase in pressure occurs, sufficient to push the spring 66, the bearing force of which is very low. A wide annular passage "a" is then created through which the fluid easily passes into the second chamber 13. When the piston 13 has moved back enough the support 12a comes into contact with the valve 65 and drives it to finally release the passage between the nozzle 31 and the second chamber 18 of the cylinder 11.

Claims (7)

1. Device for assisting the movement of an opening (1) relative to a frame (3) comprising an opening of shape complementary to that of the opening (1) said device comprising: - a movable piston (13) in a cylinder (11) and determining in this cylinder (11) first and second chambers (17,18), said piston (13) being intended to be connected to the leaf (1) or to the frame (3) and said cylinder (11) being intended to be connected to the chassis (3) or to the opening (1), - a circuit (35,36) for actuating the piston (13) by sending a fluid in one of the two chambers (17,18) for moving the opening (1) between a closed position and an open position, and - a circuit (40) for braking the hydraulic movement of the piston (13) in the cylinder (11) , characterized in that it comprises: - means (55, 56, 59) for neutralizing the braking pressure in the first chamber (17) at the end of the stroke of the piston (13) in the closed position opening (1), - means (70,72, 73,74) for increasing the braking pressure in the second chamber (18) at a determined value at the end of the piston (13) stroke in the maximum opening position of the opening (1), and - means (66) for controlling the passage of the fluid in the second chamber (18) before the displacement of said piston (13) and at the start of displacement of the opening (1) from its maximum opening position.  2. Assistance device according to claim 1, characterized in that the cylinder (11) is closed at one of its ends by a first bottom (15) and at the other of said ends by a second bottom (16) , said bottoms (15, 16) each comprising a nozzle (26,30) communicating with the corresponding chamber (17, 18) and connected to the other nozzle by a conduit (33) provided with a valve (34) movable between an open position for communicating said nozzles (26,30) and a closed position.  3. Assistance device according to claim 1 or 2, characterized in that the means for neutralizing the braking pressure comprise <Desc / Clms Page number 13>  a valve (55) disposed in the first base (15) and movable by a control member (56) under the action of the piston (13) between an opening position of the nozzle (26) of said first base (15 ) putting the first chamber (17) into communication with the duct (33) and a position for closing said nozzle (26).  4. Assistance device according to any one of claims 1 to 3, characterized in that the means for increasing the braking pressure comprise, on the one hand, a sliding valve (65) intended to be applied under the action of the piston (13) against a seat (67) of complementary shape formed in the bottom (16) to close a central orifice (32) for the flow of fluid between the second chamber (18) and the braking circuit (40 ) and, on the other hand, a first calibrated passage (72) of the fluid between the second chamber (18) and said second adjustment (31).  5. Assistance device according to claim 4, characterized in that the means for increasing the braking pressure comprise a second passage (72) calibrated of the fluid between the second chamber (18) and the second nozzle (31) and a spring (74) calibrated with a determined force to maintain said valve (73) applied against a seat formed at one end of said second passage (72) until the pressure in the second chamber (13) exceeds the calibration force of said spring (74).  6. Assistance device according to the preceding claim, characterized in that the means for controlling the passage of the fluid are formed by a spring (66) interposed between the valve (65) and the piston (13).  7. Motor vehicle comprising an opening (1) articulated on a chassis (3) provided with an opening of shape complementary to that of the opening, between an open position and a closed position of this opening (1) by relative to this frame (3), characterized in that it comprises a device for assisting the movement of said opening (1) according to any one of claims 1 to 6.