MXPA97008467A - Hidraul antivibration support - Google Patents

Abstract

The present invention relates to a hydraulic anti-vibration support designed to interpose between two rigid elements to dampen and attenuate vibratory movement between these two elements along a central axis and to support an axial load exerted by one of these two elements, the support comprising: first and second rigid reinforcements designed to be fastened to respective elements of the two rigid elements to be joined, an elastomer body connecting the two reinforcements, the elastomer body supports the axial load and has a lateral wall in the form of axially extending bell, which is flared down from a fixed upper part to the first frame to an annular base fixed to the second frame, a flexible and easily deformable elastomeric wall having a peripheral edge connected in a hermetic manner to the second armature, and cooperates with it and with the elastomer body to define a housing seal The liquid filled housing is a rigid barrier which is attached to the second armature and extends perpendicularly to the central axis, thus subdividing the sealed housing in two liquid-filled chambers, namely a working chamber defined in part by the elastomer body, and a compression chamber defined in part by the flexible elastomer wall, a narrow passage that interconnects the working and compensation chambers, the channel has a certain length L and a certain diameter D equivalent so that the L / D ratio is higher to 10: a central nozzle formed through the rigid barrier to connect the working and compensation chambers to the central nozzle has an axial length l and an equivalent diameter d such that the ratio l / d is less than 10; attached to a central part of the flexible elastomer wall and axially displaceable between the closed position where the nozzle is sealed and a position n opening, where the nozzle opens, a control device for selectively positioning the shutter, either in its opening position or in its lock position, the control device includes a drive member that is fixed to the shutter; less a passage formed through the rigid barrier between the working and compensation chambers, in a position that is located radially to the outside of the nozzle, the passage is closed by a valve that extends perpendicular to the central axis and has two opposite surfaces communicating respectively with the working chamber and with the compensation chamber, the valve has at least one part displaceable parallel to the central axis between the first and the second stops, with a set at 1 millimeter the first stop is joined with the rigid barrier where the second stop of the valve is mounted with an axial clearance of less than 1 millimeter between the valve and a contract attached to the rigid barrier, this second stop is in mechanical relationship with the obturator, the second stop is pressed against the valve by the obturator when in its open position, substantially preventing any axial movement of the valve, and the second stop is pressed against the contract. by the shutter when you are in your closed position

Description

HYDRAULIC ANTIVIBRATOR SUPPORT The present invention relates to hydraulic anti-vibration mounts, especially designed to support the motors of automotive vehicles. More particularly, the invention relates to a hydraulic anti-vibration support intended to be interposed between two rigid elements to dampen and attenuate the vibratory movements between these two elements according to a central axis and to support an axial load exerted by one of these two elements, this The support comprises: a first and a second rigid reinforcement designed to join respectively the two rigid elements to be assembled. - an elastomer body that joins the two reinforcements together, the elastomer body supporting the axial load and having a bell-shaped side wall extending axially in divergence after a solidary top of the first reinforcement in a base annular attached to the second armor. a flexible and easily deformable elastomer wall, having a peripheral edge sealingly connected to the second reinforcement, thereby defining the elastomer body as an airtight container filled with liquid, - a rigid barrier which is attached to the second reinforcement and which it extends perpendicularly to the central axis separating the hermetic container in two chambers filled with liquid, namely, on the one hand a working chamber partially delimited by the elastomer body, and on the other hand, a compensation chamber partially delimited by the flexible wall of elastomer, a throttled channel connected between the working and compensation chambers, the channel having a certain length in L and a certain equivalent diameter D so that the ratio L / D is greater than 10, - a central nozzle provided in the rigid barrier for communicating the working and compensation chambers, the central nozzle having a length of ax ial 1 and an equivalent diameter d, so that the ratio 1 / d is less than 10, - a shutter integral with a central part of the elastomer flexible wall and axially displaceable between, on the one hand, a closed position where sealing the nozzle, and on the other hand an opening position where the nozzle opens, - a control device for selectively positioning the shutter, either in its opening position, or in its closed position, the control device including a drive which is connected to the sealing member, and at least one passage provided in the rigid barrier between the working and compensation chambers, in a position located radially to the outside of the nozzle, the passage being sealed by a valve extending perpendicular to the central axis and having two opposite faces communicating respectively with the working chamber and with the compensation chamber, said valve having at least one part displaceable parallel to the central axis between a first and a second stop, with a play less than 1 millimeter, the first stop being joined to the rigid barrier. Such hydraulic anti-vibration support is described, for example, in EP-A-0 547 287. The anti-vibration support presented in this document, however, has the disadvantage that the valve is always free to vibrate between the two stops until when the central nozzle is open. However, experience shows that this phenomenon impairs the operating efficiency of the central nozzle: in other words, as the opening of the central nozzle is essentially aimed at reducing the elastic stiffness of the antivibration support, especially while the engine is running at slow running, the fact that the valve is free to vibrate in this situation prevents the elastic rigidity of the support from decreasing, while it could decrease if the valve is blocked.

On the other hand, EP-A-0297 974 discloses a hydraulic antivibration support in which it is envisaged to block the decoupling valve while operating a nozzle between the working chamber and the compensation chamber. The operation of this last hydraulic anti-vibration support is totally satisfactory, but this support has the drawback of resorting to relatively complex control means. Furthermore, the control means in question are then mounted on the side of the hydraulic anti-vibration support, which increases the volume of the support and considerably complicates its assembly and filling. The present invention aims to alleviate the various inconveniences mentioned above. For this purpose, according to the invention, a hydraulic anti-vibration support of the kind in question is essentially characterized in that the second stop of the valve is mounted with an axial play of less than 1 millimeter between the valve and a contractor attached to the rigid barrier, this being second stop in mechanical relationship with the obturator, the second stop being applied against the valve by the obturator while the obturator is in its open position, thereby substantially preventing any axial movement of the valve, and said second stop being applied against the contrappa through the shutter while it is in its closed position. In preferred embodiments, it is also possible to resort to one and / or other of the following arrangements: the first stop is in contact with the surface of the valve communicating with the compensation chamber while the second stop is in contact with the surface of the valve communicating with the working chamber, the nozzle being delimited externally by means of a tube extending along the central axis, starting from a first end joined with the second stop, in the direction of the flexible elastomer wall to a second end having at least one outer flange, the shutter being axially applied against this second end towards the body of this elastomer while said shutter is in its closed position by axially applying the second stop on the contrappel, and the shutter being joined with an assembly of teeth around the tube and running axially around the tube, these teeth have a size to abut on the flange of the second end of the tube emerging from said tube and the second stop against the flexible elastomer wall while the obturator is in its open position, so that the second stop is then applied against The valve; the teeth are constituted by elastic metal legs that are cut out of the same piece of sheet metal fixed to the obturator and that are ratcheted on the tube that delimits the nozzle, - - the piece of sheet metal on which the elastic legs are cut presents a central part that is interposed between the obturator and the elastomer flexible wall, each elastic leg extends axially in a direction in the direction of the rigid barrier and radially inward from this central part to a free end forming an axial collar elastic support against the tube and directed towards the outer flange of the tube; the teeth are two in number and are arranged on the one hand and on the other part of the tube delimiting the nozzle; the control device consists of a low-pressure capsule which is disposed close to the flexible elastomer wall outside the hermetic container, this capsule at low pressure has a hollow interior volume which communicates, by means of an electro-valve, either with the atmosphere, either with a source of low pressure, this hollow interior volume is partially delimited by a moving wall that constitutes the actuator of the obturator and that is axially displaceable towards the inside of the capsule with low pressure dragging the obturator to its position open and applying the second stop against the valve when the capsule at low pressure communicates with the source of low pressure, and the internal volume of the capsule at low pressure comprises, on the other hand, a spring that incites the mobile wall against the airtight container filled with liquid thus placing the obturator in its closed position and applying the second stop on the corresponding contract, while the low pressure capsule communicates with the atmosphere; the capsule at low pressure has a rigid fixed wall that joins the second frame, the mobile wall of this capsule has a rigid central part which is hermetically connected to the fixed wall by means of an annular elastomer bellows; the valve has an annular shape around the central nozzle, the first and second stops of the valve are constituted by annular teeth; the obturator is constituted by a rigid overmolded elastomer washer, the central part of the elastomer flexible wall having a rigid overmolded elastomer washer, the two washers and the shutter activating member being assembled together by means of a rivet which traverses them axially. Other features and advantages of the invention will appear in the course of the following detailed description of one of its embodiments, given by way of non-limiting example, with respect to the accompanying drawings. On the drawings: Figure 1 is a vertical sectional view of a hydraulic anti-vibration support according to an embodiment of the invention, with its central nozzle closed, and Figure 2 is a partial view of the support of Figure 1 with its nozzle open center. In the description that follows, terms such as "up", "down", "top", "bottom", etc., are used solely for the purpose of making the description clearer, but are not in any way limiting. The hydraulic anti-vibration support considered here is intended to be interposed vertically between a vehicle power unit and a vehicle chassis, to support the weight of the motor-drive pad and to dampen and attenuate the anti-vibration movements between these two elements along a vertical axis Z. This support The antivibration device comprises: a first rigid metal armor 1 that can be fixed, for example, to the propulsion block, this first reinforcement being constituted by a central contact 2 prolonged upwards by a bolt 3 that allows the fixing with an element integral with the power-train block. - a second rigid metallic armor 4 in the shape of a ring centered on the Z axis, this second reinforcement forming a plane 5 that locally has fixing legs (not shown) pierced with holes to fix the second reinforcement to the chassis. - an elastomer body 6 joining together the two reinforcements 1, 4, the elastomer body being sufficiently strong to support the axial load imposed on the support by the power unit block, and said elastomer body having a bell-shaped side wall which can have a form of revolution centered on the Z axis and which extends in divergence downwards after a solidary apex of the first reinforcement to an annular base integral with the second reinforcement. a flexible deformable flexible wall 7 of elastomer, having a peripheral edge sealingly connected to the second reinforcement 4, defining with it and the elastomer body an airtight container filled with liquid. and a rigid barrier 8 which is connected to the second reinforcement 4 by the flange of said second reinforcement and extending perpendicularly to the axis Z separating the hermetic container in two chambers filled with liquid, namely on the one hand a working chamber A bounded partially by the elastomer body 6, and on the other hand, a compensation chamber B partially delimited by the flexible elastomer wall 7.

The barrier 8 comprises a lower metal plate 9 having a thick outer edge in which a groove 10 is formed, which opens axially upwards. This throat is covered by a metal washer 11, the stacking of the plate 9 and the washer 11 is held axially tight by the crimping of the second reinforcement 4. The throat 10 delimits with the washer 11 a throttle channel 12 that extends angularly between two extremities separated one from the other by a thick-filled part of the plate 9. This throttled channel opens, on the one hand, axially, in the working chamber A through the intermediary of an orifice 13 provided in the washer 11, and this on the other hand, runs radially inwards in the compensation chamber B, by means of a hole 14 provided in the lower plate 9. The throttled channel 12 has a certain length L and a certain equivalent diameter D (D = 2 [S / p] 1'2, where S is the largest right section of channel 12) in such a way that the S / D ratio is greater than 10, and is generally between 10 and 100. The choked channel 12 pe In order to effectively dampen the relative vibrational movements of a relatively weak frequency (for example, below 20 Hz) and a relatively large amplitude (for example, greater than 1 millimeter) between the power unit and the chassis of the vehicle, these vibratory movements are especially responsible for to the bearing of the vehicle. On the other hand, the lower plate 9 has a central hole 15, and this plate forms, on the other hand, between its thick edge and the hole 15, an annular grid 16, flat and horizontal. The barrier 8 comprises, on the other hand, an annular metal part 17 having a general shape of revolution around the axis Z and comprises a flat horizontal grid 18 in which the inner radial edge is extended axially downwards by means of a tube 19. This tube 19 it extends to a lower extremity provided with an outwardly projecting shoulder 20 forming an upwardly directed backrest. The tube 19 is fitted with play in the central hole 15 of the plate 9, this central hole being sufficiently wide to allow passage of the flange 20. On the other hand, the grid 18 is disposed above the grid 16 and is maintained in the vicinity of the grid 16 by the inner edge Ia of the washer 11, which covers the periphery of said grid 18. In addition, between the two grids 16 and 18 a valve 21 is received which is presented in the form of a thin flat washer of elastomer wherein the outer and inner edges are in radially sealed contact respectively, with the thick outer edge of the plate 9 and with the tube 19. Optionally, to facilitate the hermetic contact, the inner and outer edges of the valve 21 can form two thin-sealed lips, presenting for example a beveled profile forming a lip of exclusive sealing, and having the outer edge the inner edge of the valve, for example, a groove radial ring that delimits two hermetic lips. When the grid 18 is bumped against the washer 11, the valve 21 can move freely axially between the grids 16 and 18 with a weak axial play, generally less than 1 millimeter and for example, of the order of 0.5 millimeters. In this configuration, the valve 21 allows absorbing the vibratory movements of the relatively high frequency drive block (for example, greater than 50).

Hz) and relatively low amplitude (for example, less than 1 millimeter). On the other hand, the tube 19 internally delimits a nozzle 22 which directly communicates the working chamber A with the compensation chamber B and which has a length 1 and a diameter d (or an equivalent diameter d, with the same definition as the given above for diameter D). so that the ratio 1 / d is less than 10, for example, comprised between 0.5 and 10. This nozzle 22 can be selectively closed or opened by means of a shutter23 is controlled, for example, by means of a low-pressure capsule 24 located under the flexible wall 7. The plug 23 is, for example, in the form of an elastomer washer which is overmoulded on a metal washer 25, which is integral, with another metal washer 26 also overmoulded with elastomer, which constitutes the central part of the flexible wall 7. Between the two washers 25 and 26, the central part of a cut sheet piece 27 is interposed, which extends radially outwards by means of two legs elastic diametrically opposed that fold towards the top and towards the tube 19, each of the legs 28 is terminated by a collar 29 folded down and sliding against the outer surface of the tube 19. Eventually, the legs 28 could be in number of three . On the other hand, the low-pressure capsule 24 comprises: a rigid sheet wall 30, in the form of a trough, a rigid metal ring 31 stacked on the periphery of the wall 30 and connected to this wall as well as to the second reinforcement 4, the assembly constituted by the contour of the flexible wall 7, the contour of the ring 31 and the contour of the wall 30 being pressed axially against the lower part of the lower part of the metal plate 9 by beading of the second reinforcement 4, and a movable wall 32 comprising a horizontal rigid metal central plate 33 joined to the ring 31 by means of an annular elastomer bellows 34 overmolded on the inner and outer edges, respectively, of the ring 31 and of the plate 33. The plate 33 is joined with the central part of the flexible elastomer wall 7 by means of a rivet 35 which passes through and integrates the stack constituted by the washer 25, the central part of the piece of c hapa 27, the washer 26, and the plate 33. The low pressure capsule 24 has, between the walls 30 and 32, an interior volume 36 that communicates either with the atmosphere, or with a low pressure source 37. (engine air intake circuit or possibly vacuum pump, by means of a three-way electro-valve 38 which is controlled by a computer 39 or some other control system.) Furthermore, a compression spring 40 is disposed between the wall 30 and plate 33, so as to incite plate 33 upwards It will be noted, on the other hand, that wall 30 and ring 31 are perforated with at least one hole 41 below moving wall 32, for communicating with the atmosphere the intermediate space between the wall 32 and the flexible wall 7, so that these two walls are freely deformable without generating high pressure or low pressure in this interspace During the normal operation of the vehicle, the electro-valve 38 causes the internal volume 36 of the capsule to be communicated with the atmosphere at low pressure, so that the obturator 23 is axially applied against the lower extremity of the cap. tube 19 thus closing the nozzle 22. Consequently, the grid 18, which is integral with the tube 19, is also applied in abutment against the inner edge of the washer 11, so that the valve 21 can move freely vertically between the two grids 16 and 18. On the contrary, in certain operating modes of the vehicle and especially when the engine is running at idle speed, it is desirable to immobilize the valve 21 and open the nozzle 22. With this end, the computer 39 controls the electro valve 38 for communicating the internal volume 36 of the capsule at low pressure with the low pressure source 37. In this case, as shown in figure 2, the mobile wall 32 of the capsule at low pressure moves downwards against the elastic incitement of the spring 40, thus opening the nozzle 22. Furthermore, the collars 29 of the grids 28 then come to abut against the front flange 20 of the tube 19, thus pulling down the grid 18, which then comes to bump against the valve 21 and to immobilize it. In this position, a very weak antivibratory support elastic tension is obtained, with an excellent absorption of the vibrations produced by the engine at neighboring frequencies at for example 30 Hz.

Claims (2)

CLAIMS 1. A hydraulic antivibration support designed to interpose between two rigid elements to cushion and attenuate the vibratory movements between these two elements according to a central axis (Z) and to support an axial load exerted by one of these two elements, the support comprises: first and second rigid reinforcements (1, 4) intended to be joined respectively with the two rigid elements to be assembled. - an elastomer body (6) joined between the two reinforcements, this elastomer body supports the axial load and has a bell-shaped side wall extending axially in divergence after a summit joined with the first reinforcement (1) up to an annular base joined with the second reinforcement (4). a flexible and easily deformable wall (7) elastomer, which has a peripheral edge hermetically connected to the second reinforcement (4), defining with it and with the elastomer body (6) a sealed container filled with liquid. a rigid barrier (8) which is integral with the second reinforcement (4) and which extends perpendicularly to the central axis (Z) separating the hermetic container in two liquid-filled chambers, namely, on the one hand, a working chamber ( A) partially delimited by the elastomer body, and on the other hand, a compensation chamber (B) partially delimited by the flexible elastomer wall, a throttled channel (12) that joins together the working and compensation chambers (A , B), this channel has a certain length L and a certain equivalent diameter D such that the L / D ratio is greater than 10. a central nozzle (22) placed on the rigid barrier to make the working and compensation chambers communicate (A, B) this nozzle has an axial length 1 and an equivalent diameter d such that the proportion

1 / d is less than 10. a shutter (23) attached to a central part of the flexible wall (7) of elastomer and axially displaceable between, on the one hand, the closed position where the nozzle (22) closes and for another part, an opening position, where said nozzle opens, a control device (24) for selectively positioning the shutter, either in its opening position, or in its lock position, this control device includes an organ of drive (32) which is connected to the sealing member. and at least one passage placed within the rigid barrier (8) between the working and compensation chambers (A, B), in a position located radially to the outside of the nozzle (22), this passage is sealed by a valve ( 21) extending perpendicularly to the central axis (Z) and having two opposite surfaces communicating respectively with the working chamber and with the compensation chamber, the valve having at least one part displaceable parallel to the central axis (Z) between the first and the second stops (16, 18), with a play less than 1 millimeter, the first stop (16) is joined with the rigid barrier. characterized in that the second stop (18) of the valve is mounted with an axial play of less than 1 millimeter between the valve (21) and a contractor (lia) joined with the rigid barrier, this second stop is in mechanical relation with the shutter ( 23), the second stop is applied against the valve by the obturator while it is in its open position, then substantially preventing any axial movement of the valve and said second stop is applied against the contrap by the obturator while it is in its lock position.

2. A hydraulic anti-vibration mount according to claim 1, in which the first stop (16) is in contact with the surface of the valve (21) communicating with the compensation chamber, while the second stop (18) is in contact with the surface of the valve communicating with the working chamber, the nozzle being delimited externally by means of a tube (19) extending along the central axis (Z), from a first end joined to the second stop (18), in the direction of the flexible wall (7) of elastomer to a second end having at least one outer flange (20), the shutter (23) is applied axially against this second end towards the elastomer body (6) while said shutter is in its closed position by then axially applying the second stop (18) on the contractile (lia), the shutter being attached to an assembly of teeth (28) around of the tube (19) and sliding axially around the tube, the teeth are sized to abut the rim (20) of the second end of the tube by then pulling the said tube and the second stop against the flexible elastomer wall while the obturator it is in its opening position, so that the second stop is then applied against the valve. Hydraulic anti-vibration support according to claim 2, in which the teeth (28) are constituted by elastic metal legs that are cut out in a same piece of sheet (27) fixed to the obturator (23) and that are entangling on the tube ( 19) that delimits the nozzle. Hydraulic antivibration support according to claim 3, in which the sheet metal part (27) in which the elastic legs (28) are cut out has a central part that is interposed between the obturator (23) and the flexible wall (7). ) elastomer, each elastic leg extends axially in the direction of the rigid barrier (8) and radially inward from this central part to a free end that forms an axial collar (29) in resilient support against the tube and directed towards the outer flange (20) of that tube. Hydraulic anti-vibration support according to any of claims 2 to 4, in which the teeth (28) are two in number and are arranged on one side and on the other side of the tube (19) delimiting the nozzle. Hydraulic anti-vibration support according to any of the preceding claims, in which the control device consists of a low pressure capsule (24) which is disposed in the vicinity of the flexible elastomer wall (7) to the outside of the hermetic container, this capsule at low pressure has a hollow interior volume (36) that communicates, by means of an electro-valve (38), either with the atmosphere, or with a low pressure source (37), the hollow interior volume is partially delimited by a movable wall (32) that constitutes the actuator of the obturator and that can be displaced axially towards the interior of the capsule at low pressure bringing the obturator (23) to its open position, and applying the second stop (18). ) against the valve (21) while the low pressure capsule communicates with the source of low pressure, and the internal volume of the capsule at low pressure comprises on the other hand, a spring (4). 0) that incites the mobile wall (32) against the airtight container filled with liquid, thus placing the obturator (23) in its closed position and applying the second stop (18) on the corresponding contract (lia) while the capsule at low pressure it communicates with the atmosphere. Hydraulic anti-vibration support according to claim 6, in which the low-pressure capsule (24) has a fixed rigid wall (30) which is connected to the second reinforcement (4), the mobile wall (32) of this capsule has a rigid central part (33) that is hermetically connected to the fixed wall by an annular elastomer bellows (34). Hydraulic anti-vibration support according to any of the preceding claims, in which the valve (21) has an annular shape around the central nozzle (22), the first and second stop (16, 18) of the valve are constituted by annular grids. Hydraulic antivibration support according to any of the preceding claims, in which the obturator (23) is constituted by a rigid washer (25) overmolded of elastomer, the central part of the elastomer flexible wall (7) has a rigid elastomer overmoulded washer (26), these two washers and the actuator (32) of the obturator are joined in assembly by means of a rivet (35) running through them. axially.