Switchable anti-vibration hydraulic mount and separation element

A partition member of an anti-vibration hydraulic mount includes a first channel and a second channel between the working chamber and the compensating chamber. The partition member includes a membrane secured in a receiving cavity. The membrane divides the receiving cavity into two sub-spaces separated fluidically from each other. The membrane comprises a closing device configured to have an open configuration, in which the closing device is spaced apart from the central opening, and a closed configuration, in which the closing device abuts against the central opening to close the central passageway.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national phase application of and claims priority to International Patent Application No. PCT/EP2019/081781, filed Nov. 19, 2019, which claims priority to French Patent Application 1871935, filed Nov. 27, 2018, the contents of which are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The present disclosure concerns a partition member of an anti-vibration hydraulic mount, and more particularly a partition member of an anti-vibration hydraulic mount configured for mounting an engine on a vehicle body.

BACKGROUND

Anti-vibration devices for mounting an engine on a vehicle body are known, comprising a first frame connected to a second frame by means of an anti-vibration hydraulic mount able to be deformed at least along a main vibration axis.

However, this anti-vibration hydraulic mount is limited to the damping of vibration in a given range of vibration frequencies.

Also, anti-vibration hydraulic mounts are known comprising a switch allowing the dampening of vibration in at least two given ranges of vibration frequencies, for example, in normal operation and in operation with an idling engine.

However, this switch requires the presence and the control of an actuator, which can result in less good reliability of the anti-vibration device.

SUMMARY

The present disclosure aims at remedying at least part of these disadvantages.

To this effect, the present disclosure concerns a partition element or separation element configured to be arranged between a working chamber and a compensating chamber of an anti-vibration hydraulic mount or an anti-vibration hydraulic module, the separation element comprising:a first channel configured to form a permanently open passageway between the working chamber and the compensating chamber,a second channel configured to form a passageway between the working chamber and the compensating chamber, the second channel comprising a central passageway extending in an axial direction, the central passageway being provided with a central opening, a receiving cavity open towards the working chamber and in fluid communication with the central passageway through the central opening, anda membrane fixed in the receiving cavity and dividing the receiving cavity into two sub-spaces separated fluidically from each other, the membrane comprising a closing device protruding from the membrane towards the central opening and being able to adopt two configurations:the closing device being spaced apart from the central opening in an open configuration when the membrane is deformed towards the central passageway over a first distance, the closing device being spaced apart from the central opening, and

the closing device abuts against the central opening to close the central passageway in a closed configuration when the membrane is deformed towards the central passageway beyond the first distance.

Thanks to the membrane that can assume an open configuration and a closed configuration, depending on the vibration frequencies and the membrane's vibration amplitude, it is possible to modify the damping characteristics of the anti-vibration hydraulic mount in two vibration frequency ranges. The membrane thus acts like a passive switch permitting the changing of the main frequency of the damping characteristics. As the membrane does not need to be switched actively, i.e. with an actuator, between a closed position and an open position, the membrane is a passive switch permitting the changing of the damping characteristics of the anti-vibration hydraulic mount. The risk of bad operation of the anti-vibration hydraulic mount linked with the bad operation of an actuator permitting the changing of the main frequency of the damping characteristics is thus eliminated. The anti-vibration hydraulic mount is hence more robust and more reliable.

In fact, in the presence of vibrations having a high frequency, i.e. between 18 Hz and 30 Hz (hertz), but a low amplitude, i.e. in the order of 0.1 mm, the membrane vibrates at an amplitude of 0.1 mm because of the pressure difference between the working chamber and the compensating chamber. As a result of the low amplitude of the vibrations, the closing device does not block the central passageway, i.e. the membrane is in an open configuration, so that the first channel as well as the second channel contribute to the damping characteristics of the anti-vibration hydraulic mount.

When the membrane is subjected to vibrations having a low frequency, i.e. a frequency corresponding to the movement of the solid body of the engine, approximately 10 Hz, and of high amplitudes, i.e. in the order of 1 mm, the membrane is deflected in such a way that the closing device abuts against the central opening, i.e. the membrane is in a closed configuration. Hence, the central passageway is blocked. In this case, only the first channel makes a contribution to the damping characteristics of the anti-vibration hydraulic mount.

In certain embodiments, the closing device comprises an annular protrusion.

In certain embodiments, the annular protrusion shows a lateral wall.

In certain embodiments, the lateral wall is inclined relative to the axial direction of the central passageway, the annular protrusion being configured to abut against an internal circumferential wall of the central opening in a closed configuration.

The inclined lateral wall makes it possible to optimize the closing of the central opening.

In certain embodiments, the central opening shows a rounded edge.

That makes it possible to optimize the cooperation of the closing device of the membrane with the central opening.

In certain embodiments, the membrane comprises a fastening protrusion at the level of a circumferential edge of the membrane to fix the membrane in the receiving cavity.

In certain embodiments, the receiving cavity comprises a receiving groove of the fastening protrusion.

In certain embodiments, the membrane comprises at least one intermediate protuberance protruding from the membrane and arranged between the fastening protrusion and the closing device.

This intermediate protuberance makes it possible to modify the vibratory behaviour of the membrane and hence the damping characteristics of the anti-vibration hydraulic mount.

In certain embodiments, the intermediate protuberance is wedge-shaped in a cross-sectional view of the membrane.

In certain embodiments, the membrane shows an axial symmetry in the cross-sectional view of the membrane.

The membrane can thus be arranged in the receiving cavity in one direction and/or the other. What is more, the intermediate protuberance protruding from the membrane towards the aperture plate as well as the closing device protruding from the membrane towards the aperture plate make it possible to limit the deflection of from the membrane towards the aperture plate.

In certain embodiments, the second channel comprises an adjustment passageway that is in fluid communication with the central passageway and that extends partially around the central passageway in a circumferential direction, the tuning passageway being open towards the compensating chamber.

In certain embodiments, the partition member comprises a circular adjusting plate provided with a control opening and configured to be placed in the in the tuning passageway in different orientations.

The adjusting plate makes it possible to modify the length of the tuning passageway and thus the damping characteristics of the anti-vibration hydraulic mount.

In certain embodiments, the control plate comprises a plurality of lugs protruding radially from the adjusting plate.

In certain embodiments, the lugs are evenly distributed round the circumference of the control plate.

In certain embodiments, the control plate is fastened to the partition member by a plurality of fastening elements.

In certain embodiments, the fastening elements extend through the openings of the control plate that are defined by the lugs.

In certain embodiments, the partition member comprises a lower wall limiting the receiving cavity around the central opening.

In certain embodiments, the lower wall comprises a plurality of recesses.

These recesses make it possible to modify the damping characteristics of the anti-vibration hydraulic mount.

In certain embodiments, the recesses extend from the central passageway as far as the circular edge of the lower wall.

In certain embodiments, the recesses have the same shape and/or are distributed evenly in the lower wall in a circumferential direction.

In certain embodiments, the recesses have a triangular shape when seen from above.

The present disclosure likewise concerns an anti-vibration hydraulic mount comprising:a partition member such as defined previously,an elastomeric body defining, with the partition member, a working chamber,a flexible compensating membrane defining, with the partition member, a compensating chamber,the separating element separating the working chamber from the compensating chamber.

Of all the figures, the elements in common are identified by identical numerical references.

DETAILED DESCRIPTION

FIG.1shows a schematic view of an anti-vibration device10. The anti-vibration device10comprises a support12comprising a receiving housing for an anti-vibration hydraulic mount14. The anti-vibration hydraulic mount14is likewise named hydraulic module, hydromodule or hydromount. The support12is meant to be fastened to a vehicle chassis. The anti-vibration hydraulic mount14comprises a securing means16in which the vehicle's engine can be secured. In the embodiment ofFIG.1, the securing means16is a cavity.

The anti-vibration hydraulic mount14shows a configuration known in its own right.

As shown inFIG.3, the securing means16are borne by an elastic body18, for example made of elastomeric material, delimiting at least partially a working chamber20. A partition member22is fastened to the elastic body18. A compensating membrane24is fastened to the partition member22. The compensating membrane24is flexible but not extensible and delimits at least partially a compensating chamber25.

The working chamber20is delimited by the elastic body18and the partition member22. The compensating chamber25is delimited by the partition member22and the compensating membrane24.

The working chamber20and the compensating chamber25are interconnected by a first channel26and a second channel28. Hence, when loads act on the elastic body18, the volume of the working chamber20is reduced as a result of compression of the elastic body18, in such a way that a hydraulic fluid present in the working chamber20flows through the first channel26and/or through the second channel28towards the compensating chamber25and inversely.

The configuration of the partition member22can be seen better inFIGS.4,5and6.

As shown inFIGS.4A and4B, the partition member22comprises an aperture plate30, a membrane32, a main body34, and a tuning plate36. The partition member22shows a general cylindrical shape. The main body34defines the first channel26, the second channel28and a receiving cavity38for the membrane32. The receiving cavity38is a cylindrical space having a circular shape when viewed from above. The first channel26extends circumferentially around the receiving cavity38. The first channel26is open permanently, so that the fluid can always flow from the working chamber20to the compensating chamber25and vice versa. The length of the first channel26is chosen in such a way that the resonance frequency of the fluid in the first channel26is adjusted to the vibration frequency to be dampened by means of the first channel26.

The aperture plate30comprises a plurality of openings31that link the working chamber20to the receiving cavity38and to the first channel26. The aperture plate30is fastened to the main body34by means of fastening elements such as screws and/or bolts.

The second channel28comprises a central passageway40having a central opening42and a tuning passageway44. The central passageway40is open towards the receiving cavity38by means of the central opening42. The central passageway40is arranged at the centre of the main body34and extends in an axial direction X. The tuning passageway44is in fluid communication with the central passageway40and extends around the central passageway40in a circular or spiral manner. The tuning passageway44is open towards the compensating chamber25. The tuning passageway44is at least partially closed by the adjusting plate36.

The adjusting plate36comprises a tuning opening46that is arranged in such a way that it is located above the tuning passageway44irrespective of the orientation of the tuning plate36. The dimensions of the tuning opening46are designed in its width, measured in a radial direction R, and its length, measured in a circumferential direction C, in such a way that it corresponds to the width of the adjustment passageway44, while the length of the tuning opening46is much shorter than the length of the tuning passageway44, in particular, the width and the length of the tuning opening46are approximately of the same order.

The adjusting plate36comprises a plurality of lugs48, in the embodiment in theFIGS.4,5and6, six lugs48which extend radially, i.e. in the radial direction R, starting from the adjusting plate36. The lugs49are distributed35uniformly around the circumference of the circular adjusting plate36. The lugs48define the recesses among one another. The tuning plate36is fastened to the main body34with the help of securing means (not shown) such as screws and bolts. The securing means extend through the locations, for example fastening holes for screws50and are fixed in these locations. As a result of the uniform distribution of the lugs48and of the locations, the tuning plate36can be arranged on the main body34according to a plurality of orientations.

The receiving cavity38is delimited by a lower wall52and a circular wall54of the main body34. The circular wall54separates the receiving cavity38from the first channel26. The lower wall52comprises the central opening42at its centre. The lower wall52has recesses26, and in the embodiment shown three recesses56. The recesses56extend from the central opening42as far as the circular wall54. The recesses56have a triangular shape. The recesses56are preferably distributed uniformly round the circumference of the lower wall52.

The membrane32comprises a fastening projection60, an intermediate protuberance62and a closing device64, that can be formed in one piece, for example, manufactured by a moulding process. The fastening projection60is an annular rib protruding from both sides of the membrane32. The height H of the fastening projection60in the axial direction X is larger than the height of the receiving cavity38. During the fastening of the aperture plate30to the main body34, the fastening projection60is compressed, mainly in the axial direction X, between the aperture plate30and the main body34, in such a way that the membrane32is fastened to the separating element22. As shown inFIG.6A, the receiving cavity38has a receiving groove58of the fastening projection60of the membrane32.

As shown inFIG.5B, the intermediate protuberance62is arranged between the annular fastening projection60and the annular closing device64. The protuberance62is wedge-shaped in a cross-sectional view and protrudes from both sides of the membrane32. The intermediate protuberance62shows an annular shape viewed from the top of the membrane32.

In the embodiment inFIG.6B, the closing device64comprises an annular protrusion66having a lateral wall68. The annular protrusion66is wedge-shaped in a cross-sectional view and protrudes from both sides of the membrane32. The lateral wall68is inclined in relation to the axial direction X, i.e. the extending direction of the central passageway40. The central opening42shows a rounded edge42A.

As shown inFIGS.6A and6B, in the closed configuration of the membrane32, the lateral wall68of the annular protuberance66abuts against the rounded edge42A of the central opening42. Hence, when the membrane32is deflected by a certain distance or a first distance, the annular protuberance66of the closing device64abuts against the central opening42in such a way that the central passageway40is closed, blocking the flow of liquid in the second channel28.

As shown inFIGS.7A and7B, in the open configuration of the membrane32, i.e. when there is no pressure difference between the working chamber20and the compensating chamber25, the annular protuberance66and the central opening42are spaced apart from each other. Hence, hydraulic fluid can flow from the central passageway40into the recesses56and vice versa.

As shown inFIG.5B, the membrane32is symmetrical relative to a Y axis in a cross-sectional view. The parts of the intermediate protuberance62and of the annular protuberance66protruding towards the aperture plate30act as a stop to prevent an excessively large deflection of the membrane32towards the aperture plate30.

InFIG.5B, the dimensions of the membrane32have been shown. Diameter D1of an outer end of the annular protuberance66, corresponding to the largest diameter of the annular protuberance66, is between 15 and 20 mm (fifteen and twenty millimeters), preferably between 16 and 19 mm (sixteen and nineteen millimetres). In the embodiment shown, the diameter D1is about 17.5 mm (seventeen and a half millimeters). The diameter D2of an inner end of the annular protuberance66corresponding to the smallest diameter of the annular protuberance66, is between 7 and 12 mm (seven and twelve millimetres), and preferably between 8 and 11 mm (eight and eleven millimetres). In the embodiment shown, the diameter D2is about 9.5 m (nine and a half millimetres). The diameter D3of the most protruding part of the annular protuberance66is between 12 and 17 mm (twelve and seventeen millimetres) and preferably between 13 and 16 mm (thirteen and sixteen millimetres). In the embodiment shown, the diameter D3is about 14.5 mm (fourteen and a half millimetres). The thickness E of a portion of the membrane32arranged inside the annular protuberance66is between 0.5 and 2 mm (half a millimeter and two millimetres). In the embodiment shown, the thickness E is about 1.5 mm (one and a half millimetres).

The technical principle is as follows: in the presence of vibrations having a high frequency, i.e. between 20 Hz and 25 Hz (hertz), but a low amplitude, i.e. of the order of 0.1 mm, the membrane32vibrates at an amplitude of 0.1 mm due to the difference in pressure between the working chamber20and the compensating chamber25. As a result of the low amplitude of the vibrations, the closing device64does not block the central passageway40so that the first channel26as well as the second channel28contribute to the damping characteristics of the anti-vibration hydraulic mount14.

When the membrane32is subjected to vibrations having a low frequency, i.e. an idling frequency of the engine of approximately 10 Hz, and of high amplitudes, i.e. of the order of 1 mm, the membrane32is deflected in such a way that the closing device64abuts against the central opening42. Hence, the central passageway40is blocked. In this case, only the first channel26contributes to the damping characteristics of the anti-vibration hydraulic mount14. That means that in the presence of vibrations having a high amplitude and a low frequency, only the first channel26contributes to the damping characteristics of the anti-vibration hydraulic mount14, whilst in the presence of vibrations having a high frequency and a low amplitude, the first channel26and the second channel28contribute to the damping characteristics of the anti-vibration hydraulic mount. Consequently, the damping characteristics of the anti-vibration hydraulic mount14differ in the two frequency ranges in such a way that the membrane32acts like a passive switch for changing the main frequency of the damping characteristics. As the membrane32does not need to be switched actively between a closed position and an open position, the membrane32is a passive switch making it possible to change the damping characteristics of the anti-vibration hydraulic mount14.

It has been ascertained that the recesses56and the intermediate protuberance62are elements making it possible to modify the damping characteristics of the anti-vibration hydraulic mount14. However, the way in which the intermediate protuberance62and the recesses56contribute to this effect is not unequivocal. Hence, the central protuberance62and some recesses56could be different.

As the adjusting plate36can be fastened to the main body34in different positions and as consequently the tuning opening46can be arranged in different positions in the tuning passageway44, the length of the second channel28can be modified. Hence, by changing the orientation of the adjusting plate36, the damping characteristics of the second channel28can easily be adjusted to the engine configured to be connected to the anti-vibration hydraulic mount14. For example, as a function of the position of the tuning opening46, the anti-vibration hydraulic mount14can be used for the damping of a three-cylinder engine as well as for the damping of a four-cylinder engine. As a consequence, the anti-vibration hydraulic mount14and, in particular, the partition member22, can be used for different engines. Only the orientation of the adjusting plate36will have to be adapted to the different engines.

Even though the present disclosure has been described by referring to an example of specific realization, it is apparent that different modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. What is more, individual characteristics of the different embodiments mentioned can be combined in additional embodiments. Consequently, the description and the drawings can be considered in an illustrative rather than a restrictive sense.