Patent Description:
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.

<CIT> refers to a hydromount which includes a partition plate having a channel connecting a working chamber to a compensating chamber. <CIT> deals with ways of changing the length of the channel. <CIT> also discloses a hydromount and deals with the technical problem that, over time, the elasticity of an elastic spring decreases. This may be compensated by increasing the amount of deflection of a separating membrane. <CIT> refers to a hydromount having a central passage in which a membrane is arranged. The membrane has a cylindrical buffer portion for closing the central passage. <CIT> discloses a vibration isolating apparatus wherein the transit resistance of a liquid in a second orifice is smaller than that in the first orifice and therefore, reducing vibrations in a range from low to high frequencies.

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

To this effect, the present presentation 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:.

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 <NUM> and <NUM> (hertz), but a low amplitude, i.e. in the order of <NUM>, the membrane vibrates at an amplitude of <NUM> 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 <NUM>, and of high amplitudes, i.e. in the order of <NUM>, 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.

The closing device comprises an annular protrusion.

The annular protrusion shows a lateral wall.

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.

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 presentation likewise concerns an anti-vibration hydraulic mount comprising:.

Other characteristics and advantages of the subject matter of the present presentation can be seen from the following description of the embodiments, given as non-limiting examples, with reference to the attached figures.

<FIG> shows a schematic view of an anti-vibration device <NUM>. The anti-vibration device <NUM> comprises a support <NUM> comprising a receiving housing for an anti-vibration hydraulic mount <NUM>. The anti-vibration hydraulic mount <NUM> is likewise named hydraulic module, hydromodule or hydromount. The support <NUM> is meant to be fastened to a vehicle chassis. The anti-vibration hydraulic mount <NUM> comprises a securing means <NUM> in which the vehicle's engine can be secured. In the embodiment of <FIG>, the securing means <NUM> is a cavity.

The anti-vibration hydraulic mount <NUM> shows a configuration known in its own right.

As shown in <FIG>, the securing means <NUM> are borne by an elastic body <NUM>, for example made of elastomeric material, delimiting at least partially a working chamber <NUM>. A partition member <NUM> is fastened to the elastic body <NUM>. A compensating membrane <NUM> is fastened to the partition member <NUM>. The compensating membrane <NUM> is flexible but not extensible and delimits at least partially a compensating chamber <NUM>.

The working chamber <NUM> is delimited by the elastic body <NUM> and the partition member <NUM>. The compensating chamber <NUM> is delimited by the partition member <NUM> and the compensating membrane <NUM>.

The working chamber <NUM> and the compensating chamber <NUM> are interconnected by a first channel <NUM> and a second channel <NUM>. Hence, when loads act on the elastic body <NUM>, the volume of the working chamber <NUM> is reduced as a result of compression of the elastic body <NUM>, in such a way that a hydraulic fluid present in the working chamber <NUM> flows through the first channel <NUM> and/or through the second channel <NUM> towards the compensating chamber <NUM> and inversely.

The configuration of the partition member <NUM> can be seen better in <FIG>, <FIG> and <FIG>.

As shown in <FIG> and <FIG>, the partition member <NUM> comprises an aperture plate <NUM>, a membrane <NUM>, a main body <NUM>, and a tuning plate <NUM>. The partition member <NUM> shows a general cylindrical shape. The main body <NUM> defines the first channel <NUM>, the second channel <NUM> and a receiving cavity <NUM> for the membrane <NUM>. The receiving cavity <NUM> is a cylindrical space having a circular shape when viewed from above. The first channel <NUM> extends circumferentially around the receiving cavity <NUM>. The first channel <NUM> is open permanently, so that the fluid can always flow from the working chamber <NUM> to the compensating chamber <NUM> and vice versa. The length of the first channel <NUM> is chosen in such a way that the resonance frequency of the fluid in the first channel <NUM> is adjusted to the vibration frequency to be dampened by means of the first channel <NUM>.

The aperture plate <NUM> comprises a plurality of openings <NUM> that link the working chamber <NUM> to the receiving cavity <NUM> and to the first channel <NUM>. The aperture plate <NUM> is fastened to the main body <NUM> by means of fastening elements such as screws and/or bolts.

The second channel <NUM> comprises a central passageway <NUM> having a central opening <NUM> and a tuning passageway <NUM>. The central passageway <NUM> is open towards the receiving cavity <NUM> by means of the central opening <NUM>. The central passageway <NUM> is arranged at the centre of the main body <NUM> and extends in an axial direction X. The tuning passageway <NUM> is in fluid communication with the central passageway <NUM> and extends around the central passageway <NUM> in a circular or spiral manner. The tuning passageway <NUM> is open towards the compensating chamber <NUM>. The tuning passageway <NUM> is at least partially closed by the adjusting plate <NUM>.

The adjusting plate <NUM> comprises a tuning opening <NUM> that is arranged in such a way that it is located above the tuning passageway <NUM> irrespective of the orientation of the tuning plate <NUM>. The dimensions of the tuning opening <NUM> are 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 passageway <NUM>, while the length of the tuning opening <NUM> is much shorter than the length of the tuning passageway <NUM>, in particular, the width and the length of the tuning opening <NUM> are approximately of the same order.

The adjusting plate <NUM> comprises a plurality of lugs <NUM>, in the embodiment in the <FIG>, <FIG> and <FIG>, six lugs <NUM> which extend radially, i.e. in the radial direction R, starting from the adjusting plate <NUM>. The lugs <NUM> are distributed <NUM> uniformly around the circumference of the circular adjusting plate <NUM>. The lugs <NUM> define the recesses among one another. The tuning plate <NUM> is fastened to the main body <NUM> with the help of securing means (not shown) such as screws and bolts. The securing means extend through the locations, for example fastening holes for screws <NUM> and are fixed in these locations. As a result of the uniform distribution of the lugs <NUM> and of the locations, the tuning plate <NUM> can be arranged on the main body <NUM> according to a plurality of orientations.

The receiving cavity <NUM> is delimited by a lower wall <NUM> and a circular wall <NUM> of the main body <NUM>. The circular wall <NUM> separates the receiving cavity <NUM> from the first channel <NUM>. The lower wall <NUM> comprises the central opening <NUM> at its centre. The lower wall <NUM> has recesses <NUM>, and in the embodiment shown three recesses <NUM>. The recesses <NUM> extend from the central opening <NUM> as far as the circular wall <NUM>. The recesses <NUM> have a triangular shape. The recesses <NUM> are preferably distributed uniformly round the circumference of the lower wall <NUM>.

The membrane <NUM> comprises a fastening projection <NUM>, an intermediate protuberance <NUM> and a closing device <NUM>, that can be formed in one piece, for example, manufactured by a moulding process. The fastening projection <NUM> is an annular rib protruding from both sides of the membrane <NUM>. The height H of the fastening projection <NUM> in the axial direction X is larger than the height of the receiving cavity <NUM>. During the fastening of the aperture plate <NUM> to the main body <NUM>, the fastening projection <NUM> is compressed, mainly in the axial direction X, between the aperture plate <NUM> and the main body <NUM>, in such a way that the membrane <NUM> is fastened to the separating element <NUM>. As shown in <FIG>, the receiving cavity <NUM> has a receiving groove <NUM> of the fastening projection <NUM> of the membrane <NUM>.

As shown in <FIG>, the intermediate protuberance <NUM> is arranged between the annular fastening projection <NUM> and the annular closing device <NUM>. The protuberance <NUM> is wedge-shaped in a cross-sectional view and protrudes from both sides of the membrane <NUM>. The intermediate protuberance <NUM> shows an annular shape viewed from the top of the membrane <NUM>.

In the embodiment in <FIG>, the closing device <NUM> comprises an annular protrusion <NUM> having a lateral wall <NUM>. The annular protrusion <NUM> is wedge-shaped in a cross-sectional view and protrudes from both sides of the membrane <NUM>. The lateral wall <NUM> is inclined in relation to the axial direction X, i.e. the extending direction of the central passageway <NUM>. The central opening <NUM> shows a rounded edge 42A.

As shown in <FIG>, in the closed configuration of the membrane <NUM>, the lateral wall <NUM> of the annular protuberance <NUM> abuts against the rounded edge 42A of the central opening <NUM>. Hence, when the membrane <NUM> is deflected by a certain distance or a first distance, the annular protuberance <NUM> of the closing device <NUM> abuts against the central opening <NUM> in such a way that the central passageway <NUM> is closed, blocking the flow of liquid in the second channel <NUM>.

As shown in <FIG>, in the open configuration of the membrane <NUM>, i.e. when there is no pressure difference between the working chamber <NUM> and the compensating chamber <NUM>, the annular protuberance <NUM> and the central opening <NUM> are spaced apart from each other. Hence, hydraulic fluid can flow from the central passageway <NUM> into the recesses <NUM> and vice versa.

As shown in <FIG>, the membrane <NUM> is symmetrical relative to a Y axis in a cross-sectional view. The parts of the intermediate protuberance <NUM> and of the annular protuberance <NUM> protruding towards the aperture plate <NUM> act as a stop to prevent an excessively large deflection of the membrane <NUM> towards the aperture plate <NUM>.

In <FIG>, the dimensions of the membrane <NUM> have been shown. Diameter D1 of an outer end of the annular protuberance <NUM>, corresponding to the largest diameter of the annular protuberance <NUM>, is between <NUM> and <NUM> (fifteen and twenty millimeters), preferably between <NUM> and <NUM> (sixteen and nineteen millimetres). In the embodiment shown, the diameter D1 is about <NUM> (seventeen and a half millimeters). The diameter D2 of an inner end of the annular protuberance <NUM> corresponding to the smallest diameter of the annular protuberance <NUM>, is between <NUM> and <NUM> (seven and twelve millimetres), and preferably between <NUM> and <NUM> (eight and eleven millimetres). In the embodiment shown, the diameter D2 is about <NUM> (nine and a half millimetres). The diameter D3 of the most protruding part of the annular protuberance <NUM> is between <NUM> and <NUM> (twelve and seventeen millimetres) and preferably between <NUM> and <NUM> (thirteen and sixteen millimetres). In the embodiment shown, the diameter D3 is about <NUM> (fourteen and a half millimetres). The thickness E of a portion of the membrane <NUM> arranged inside the annular protuberance <NUM> is between <NUM> and <NUM> (half a millimetre and two millimetres). In the embodiment shown, the thickness E is about <NUM> (one and a half millimetres).

The technical principle is as follows: in the presence of vibrations having a high frequency, i.e. between <NUM> and <NUM> (hertz), but a low amplitude, i.e. of the order of <NUM>, the membrane <NUM> vibrates at an amplitude of <NUM> due to the difference in pressure between the working chamber <NUM> and the compensating chamber <NUM>. As a result of the low amplitude of the vibrations, the closing device <NUM> does not block the central passageway <NUM> so that the first channel <NUM> as well as the second channel <NUM> contribute to the damping characteristics of the anti-vibration hydraulic mount <NUM>.

When the membrane <NUM> is subjected to vibrations having a low frequency, i.e. an idling frequency of the engine of approximately <NUM>, and of high amplitudes, i.e. of the order of <NUM>, the membrane <NUM> is deflected in such a way that the closing device <NUM> abuts against the central opening <NUM>. Hence, the central passageway <NUM> is blocked. In this case, only the first channel <NUM> contributes to the damping characteristics of the anti-vibration hydraulic mount <NUM>. That means that in the presence of vibrations having a high amplitude and a low frequency, only the first channel <NUM> contributes to the damping characteristics of the anti-vibration hydraulic mount <NUM>, whilst in the presence of vibrations having a high frequency and a low amplitude, the first channel <NUM> and the second channel <NUM> contribute to the damping characteristics of the anti-vibration hydraulic mount. Consequently, the damping characteristics of the anti-vibration hydraulic mount <NUM> differ in the two frequency ranges in such a way that the membrane <NUM> acts like a passive switch for changing the main frequency of the damping characteristics. As the membrane <NUM> does not need to be switched actively between a closed position and an open position, the membrane <NUM> is a passive switch making it possible to change the damping characteristics of the anti-vibration hydraulic mount <NUM>.

It has been ascertained that the recesses <NUM> and the intermediate protuberance <NUM> are elements making it possible to modify the damping characteristics of the anti-vibration hydraulic mount <NUM>. However, the way in which the intermediate protuberance <NUM> and the recesses <NUM> contribute to this effect is not unequivocal. Hence, the central protuberance <NUM> and some recesses <NUM> could be different.

As the adjusting plate <NUM> can be fastened to the main body <NUM> in different positions and as consequently the tuning opening <NUM> can be arranged in different positions in the tuning passageway <NUM>, the length of the second channel <NUM> can be modified. Hence, by changing the orientation of the adjusting plate <NUM>, the damping characteristics of the second channel <NUM> can easily be adjusted to the engine configured to be connected to the anti-vibration hydraulic mount <NUM>. For example, as a function of the position of the tuning opening <NUM>, the anti-vibration hydraulic mount <NUM> can 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 mount <NUM> and, in particular, the partition member <NUM>, can be used for different engines. Only the orientation of the adjusting plate <NUM> will have to be adapted to the different engines.

Claim 1:
Partition member (<NUM>) configured to be arranged between a working chamber (<NUM>) and a compensating chamber (<NUM>) of an anti-vibration hydraulic mount (<NUM>), the partition member (<NUM>) comprising:
- a first channel (<NUM>) configured to form a permanently open passageway between the working chamber (<NUM>) and the compensating chamber (<NUM>),
- a second channel (<NUM>) configured to form a passageway between the working chamber (<NUM>) and the compensating chamber (<NUM>), the second channel (<NUM>) comprising a central passageway (<NUM>) extending in an axial direction (X), the central passageway (<NUM>) being provided with a central opening (<NUM>),
- a receiving cavity (<NUM>) open towards the working chamber (<NUM>) and in fluid communication with the central passageway (<NUM>) through the central opening (<NUM>), and
- a membrane (<NUM>) fixed in the receiving cavity (<NUM>) and separating the receiving cavity (<NUM>) into two sub-spaces separated fluidically from each other, the membrane (<NUM>) comprising a closing device (<NUM>) protruding from the membrane (<NUM>) towards the central opening ( <NUM>) and being able to assume two configurations:
- the closing device (<NUM>) being spaced apart from the central opening ( <NUM>) in an open configuration when the membrane (<NUM>) is deformed towards the central passageway (<NUM>) over a first distance, and
- the closing device (<NUM>) abutting against the central opening (<NUM>) to close the central passageway (<NUM>) in a closed configuration when the membrane (<NUM>) is deformed towards the central passageway (<NUM>) beyond the first distance, and the closing device (<NUM>) comprises an annular protuberance (<NUM>),
wherein the annular protuberance (<NUM>) shows a lateral wall (<NUM>),
wherein the lateral wall (<NUM>) is inclined in relation to the axial direction (A) of the central passageway (<NUM>), the annular protuberance (<NUM>) being configured for abutting against an internal circumferential wall of the central opening ( <NUM>) in a closed configuration, and
wherein the central opening (<NUM>) includes a rounded edge (42A).