JP2013231454A - Fluid-filled vibration prevention device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid-filled vibration prevention device having a novel structure, capable of effectively suppressing cavitation that causes abnormal noise when an impact load or the like is incurred.SOLUTION: A fluid-filled vibration prevention device 10 includes a main fluid chamber 34 and an auxiliary fluid chamber 36 communicated with each other via an orifice passage 38. The filled fluid contains 0.03 vol.% or more of a dissolved gas in an environment at room temperature and atmospheric pressure. A low adhesion energy surface 48 having a water contact angle of 90 degrees or more is provided on the inner surface of the main fluid chamber 34.

Description

  The present invention relates to a fluid-filled vibration isolator used for, for example, an automobile engine mount and the like, and is particularly effective and simple solution to abnormal noise caused by cavitation caused by input of an impact load or the like. It relates to a technology that can provide a solution.

  Conventionally, as a type of anti-vibration device such as an anti-vibration coupling body and an anti-vibration support body interposed between members constituting the vibration transmission system, an anti-vibration effect based on the fluid action of the fluid enclosed inside is provided. A fluid-filled vibration isolator to be used is known. Such a fluid-filled vibration isolator is, for example, a main liquid in which pressure fluctuation is caused based on deformation of a main rubber elastic body when vibration is input, as described in Japanese Patent Application Laid-Open No. 2005-337348 (Patent Document 1). The chamber and a sub liquid chamber in which a relative pressure fluctuation is generated between the main liquid chamber and the main liquid chamber when vibration is input are configured to communicate with each other through an orifice passage. Further, the vibration isolation effect is exhibited based on the flow action of the incompressible sealed fluid that is caused to flow through the orifice passage between the main liquid chamber and the sub liquid chamber in which relative pressure fluctuation is caused at the time of vibration input. It has become.

  By the way, in such a fluid filled type vibration isolator, abnormal noise and vibration generated when an impact load is input may be a problem. Such abnormal noise or the like is considered to be caused by cavitation bubbles generated when the pressure of the main liquid chamber is rapidly reduced by the input of an impact load.

  In order to solve such a problem, as described in Japanese Patent No. 4265613 (Patent Document 2), a short-circuit channel provided with a relief valve or the like is provided between the main liquid chamber and the equilibrium chamber, and the main liquid A structure that promptly eliminates excessive negative pressure in the chamber has also been proposed.

  However, there is a problem that a relief valve, a short-circuit channel, and the like need to be specially formed, and an increase in the number of members and a complicated structure cannot be avoided.

JP 2005-337348 A Japanese Patent No. 4265613

  The present invention has been made in the background of the above-described circumstances, and its solution problem is to provide an effective solution for abnormal noise caused by cavitation that occurs due to input of an impact load or the like. In particular, even if cavitation noise becomes a problem after the basic design is completed, it is possible to avoid cavitation noise while avoiding adverse effects on basic vibration isolation performance as much as possible. It is an object of the present invention to provide a fluid-filled vibration isolator having a novel structure that enables simple countermeasures.

  A feature of the present invention is that a relative pressure fluctuation occurs between the main liquid chamber in which a pressure fluctuation is caused based on deformation of the main rubber elastic body at the time of vibration input and the main liquid chamber at the time of vibration input. In the fluid-filled vibration isolator having a sub liquid chamber to be squeezed and an orifice passage that allows the flow of the sealed fluid between the main liquid chamber and the sub liquid chamber, A low adhesion energy surface containing 0.03% by volume or more of dissolved gas under an atmospheric pressure environment and having a water contact angle of 90 degrees or more is provided on the inner surface of the main liquid chamber. It is in a fluid-filled vibration isolator.

  In the fluid-filled vibration isolator having the structure according to the present invention, 0.03% by volume or more of dissolved gas is dissolved in a liquid which is an incompressible fluid in an environment of normal pressure and atmospheric pressure. When the pressure in the main liquid chamber drops significantly due to the input of, the aeration phenomenon, which is gaseous cavitation, occurs before the so-called vapor cavitation called so-called cavitation occurs, and the gas dissolved in the liquid becomes bubbles. Appear. The wall surface of the main liquid chamber in which aeration bubbles are particularly likely to appear is provided with a low adhesion energy surface having a water contact angle of 90 degrees or more. It becomes a lens-like or spherical shape without expanding above. As a result, bubbles are more stably expressed and maintained when the pressure in the main liquid chamber is reduced, and the bubbles exert a negative pressure absorption and mitigation action in the main liquid chamber. By being avoided, cavitation (steam cavitation) is prevented, and abnormal noise and vibration due to cavitation are effectively suppressed.

  In particular, in the present invention, for example, the material of the member constituting the main liquid chamber is changed or exposed to the main liquid chamber without changing the basic structure such as the main liquid chamber, the sub liquid chamber, and the orifice passage. By providing a low adhesion energy layer on at least a part of the inner surface of the main liquid chamber, for example, by applying a treatment to the surface of the member, it is possible to reduce abnormal noise caused by cavitation. Therefore, even after the completion of the design of the fluid-filled vibration isolator, it is possible to easily take measures against cavitation noise while avoiding the negative effects on basic vibration isolation performance as much as possible. .

  By the way, in this invention, the structures as described below can be adopted in combination as appropriate and as necessary.

  That is, in the present invention, it is possible to adopt a configuration in which the content of the dissolved gas in the sealed fluid is 61200% by volume or less in a normal temperature and atmospheric pressure environment. By setting the dissolved gas content to 61200 volume% or less in a normal temperature and atmospheric pressure environment, it is possible to avoid unnecessary gas dissolution in the sealed fluid. In addition, it is possible to avoid a decrease in the vibration isolation performance of the orifice passage resulting from the unnecessary appearance of gas even when the pressure drop in the main liquid chamber is small.

  In the present invention, the normal temperature is a temperature at which heating or cooling is not applied at least at the start of use or in the manufacturing process, and is usually 25 ° C. In addition, the atmospheric pressure is a pressure in a state where pressure is not increased or reduced at least at the start of use or in the manufacturing process, and is usually a standard atmospheric pressure.

  In the present invention, a configuration in which the low adhesion energy surface is formed by a surface treatment layer provided on a surface of a member constituting the main liquid chamber may be employed. By forming the low adhesion energy surface with the surface treatment layer, for example, the present invention can be implemented easily and efficiently as compared with the case where the entire material of the member is changed. The surface treatment for forming the low adhesion energy surface may be performed by, for example, laminating a material layer having a physical contact angle of 90 degrees or more on the surface of the member, or laminating and fixing after separate molding. However, it is possible to easily form a target low-adhesion energy surface by coating the surface of the member or performing surface treatment. Specifically, it is also possible to obtain a low adhesion energy surface by, for example, coating with fluororesin or irradiation treatment with radiation.

  Furthermore, in the present invention, the first attachment member and the second attachment member attached to each one member constituting the vibration transmission system are connected by the main rubber elastic body and supported by the second attachment member. The main liquid chamber in which a part of the wall portion is formed of the main rubber elastic body is formed on one side of the partition member, and the equilibrium chamber is formed on the other side of the partition member. The structure which provided the said low adhesion energy surface in the surface exposed to this main liquid chamber in a member may be employ | adopted.

  Adopting a partition member that partitions the main liquid chamber and the sub liquid chamber, and providing a low adhesion energy surface on the partition member makes it easy to form a low adhesion energy surface and sets the position where the low adhesion energy surface is provided. The degree of freedom is increased, and the area of the low adhesion energy surface can be easily secured.

  Further, in the present invention, it is possible to adopt a configuration in which the low adhesion energy surface is provided at a position away from the opening of the orifice passage to the main liquid chamber. By avoiding the effect of large fluid pressure due to fluid flow through the orifice passage, the appearance and persistence of dissolved gas bubbles in the main liquid chamber as described above can be stabilized, and reduction of abnormal noise due to the target cavitation, etc. The effect can be exhibited more stably.

  Furthermore, in the present invention, it is possible to employ a configuration in which a fluid retention region having irregularities is provided on the inner surface of the main liquid chamber, and the low adhesion energy surface is formed on the inner surface of the fluid retention region. it can. By forming a low adhesion energy surface in the fluid retention region, the adverse effect of fluid flow caused in the main liquid chamber during vibration input is suppressed, and the appearance and persistence of dissolved gas bubbles in the main liquid chamber as described above are stabilized. Can be achieved. As a result, it is possible to more stably obtain the effect of reducing abnormal noise caused by the intended cavitation due to dissolved gas bubbles.

  In addition, this fluid retention area | region can be formed with the recessed shape opened to the said main liquid chamber, for example. By adopting a recess shape that opens to the main liquid chamber, it is possible to secure a larger area in a region that avoids adverse effects due to fluid flow in the main liquid chamber and to form a low adhesion energy surface. In addition, such a recess-shaped fluid retention region is formed on the surface of the main rubber elastic body or formed on the surface of the partition member described above, so that it has a simple structure without increasing the number of special members. This can be realized more advantageously.

  Further, in the present invention, the powdery body that is gasified by being exposed to the sealed fluid is sealed in the containing region of the sealed fluid, and the gasified powdery body is the dissolved gas. Embodiments can be employed. In this way, a large amount of dissolved gas can be easily realized by adopting a structure in which a substance that generates gas by melting in an enclosed fluid or the like is added to a solvent in a solid or liquid state.

  At that time, the dispersoid consisting of the powdery body is a gas-mixing composite constituted by coating the surface of the dispersoid with a solid or gel-like dispersion medium that melts in the sealed fluid, A mode in which the sealed fluid is contained in the containing region is more preferable. By adopting such a composite, it becomes possible to easily handle dispersoids made of powder.

  In the present invention, any one of gelatin, pectin, and agar is particularly preferably employed as the solid or gel dispersion medium. Further, as the dispersoid made of a powdery material, a material composed of any one of ammonium chloride, ammonium sulfate, ammonium hydroxide, ammonium hydrogen carbonate, and ammonium carbonate, or a material in which a plurality of them are appropriately mixed is preferably used. Adopted.

  Furthermore, in the present invention, a configuration is adopted in which, on the low adhesion energy surface, a bubble contact angle in the sealed fluid of bubbles appearing by aeration due to a pressure drop in the main liquid chamber is 90 degrees or more. It is desirable. By increasing the contact angle of the dissolved gas bubbles appearing in the main liquid chamber on the low adhesion energy surface, the bubbles can become nearly spherical and the pressure inside the bubbles can be maintained, making the bubbles more stable in the liquid. Therefore, the pressure relaxation action of the main liquid chamber can be more effectively exhibited.

  Further, the present invention provides a secondary pressure change that causes a relative pressure fluctuation between a main liquid chamber in which a pressure fluctuation is caused based on deformation of the main rubber elastic body at the time of vibration input and the main liquid chamber at the time of vibration input. A method for manufacturing a fluid-filled vibration isolator comprising a liquid chamber and an orifice passage that allows the flow of a sealed fluid between the main liquid chamber and the sub-liquid chamber, the inner surface of the main liquid chamber A surface of a dispersoid composed of a powdery substance that is gasified by being exposed to the encapsulating fluid, including a step of forming a low adhesion energy surface having a contact angle with water of 90 degrees or more. A step of preparing a gas-mixing complex coated with a solid or gel-like dispersion medium that melts in the sealed fluid, and the gas-mixing complex is stored in the storage region of the sealed fluid and the storage Filling the region with the sealing fluid There is also a method for manufacturing a fluid-filled vibration isolator in which the gasified powdery substance in the enclosed region filled in the containing region is contained as a dissolved gas of the enclosed fluid at a concentration of 0.03% by volume or more. , Feature.

  According to such a method of the present invention, when a fluid-filled vibration isolator having a structure according to the present invention that can exhibit a reduction effect against abnormal noise caused by cavitation, etc. is manufactured, A fixed amount of dissolved gas can be easily contained, and the target fluid-filled vibration isolator can be more easily manufactured.

  In the fluid-filled vibration isolator constructed in accordance with the present invention, the dissolved gas bubbles that appear in the main liquid chamber by aeration are effectively maintained on the low adhesion energy surface, thereby absorbing negative pressure by the bubbles. The mitigating action is exhibited, and abnormal noise and vibration caused by cavitation are effectively suppressed. Moreover, since the invention effect can be obtained by providing a low adhesion energy surface on at least a part of the surface exposed to the main liquid chamber, the basic vibration isolation is possible even after the design of the fluid filled vibration isolator is completed. Measures against cavitation noise can be realized while avoiding adverse effects on performance.

1 is a longitudinal sectional view showing a fluid-filled vibration isolator as a first embodiment of the present invention. Explanatory drawing for demonstrating the bubble by aeration of the dissolved gas which appears in a main liquid chamber. The longitudinal cross-sectional view which shows the fluid enclosure type vibration isolator as 2nd embodiment of this invention. The longitudinal cross-sectional view which shows the fluid enclosure type vibration isolator as 3rd embodiment of this invention. It is a longitudinal cross-sectional view which shows the fluid enclosure type vibration isolator as 4th embodiment of this invention, Comprising: Sectional drawing corresponded in the VV cross section in FIG. The top view which shows the partition member which comprises the fluid enclosure type vibration isolator shown by FIG. The front view of the partition member shown by FIG. VIII-VIII sectional drawing in FIG. The longitudinal cross-sectional view which shows the fluid enclosure type vibration isolator as 5th embodiment of this invention. Explanatory drawing for demonstrating the test apparatus which measures the vibration proof characteristic of a fluid enclosure type vibration proof device. FIG. 10 is a graph showing the main liquid chamber pressure at the time of vibration input as a result of the vibration isolation characteristics measured for the product of the present invention having the structure shown in FIG. 1 using the test apparatus shown in FIG. . The graph which represents the transmission load at the time of the vibration input as a result of the vibration proof characteristic measured about the product of this invention of the structure shown in FIG. 1 using the test apparatus shown in FIG. 10 with the measurement result of the comparative example.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an engine mount 10 for an automobile as a first embodiment of a fluid filled type vibration damping device having a structure according to the present invention. The engine mount 10 has a structure in which a first mounting member 12 and a second mounting member 14 are elastically connected by a main rubber elastic body 16. Then, one of the first attachment member 12 and the second attachment member 14 is attached to the power unit side, and the other is attached to the vehicle body, so that the power unit is supported in a vibration-proof manner with respect to the vehicle body in the automobile. It has become. In the following description, the vertical direction means the direction in which the elastic main shaft that is the central axis of the engine mount 10 extends in principle in the vertical direction in FIG.

  More specifically, the first mounting member 12 has a circular short column shape extending in the up-down direction, and has an inverted truncated cone shape in which the lower end portion in the axial direction is reduced in diameter toward the lower side. A fixing bolt hole 18 opened at the upper end surface is provided on the central axis, and is fixed to the power unit by a fixing bolt screwed into the fixing bolt hole 18.

  The second mounting member 14 has a large-diameter substantially cylindrical shape extending in the vertical direction, and is fixed to the vehicle body via a mounting bracket (not shown), for example. Further, the second mounting member 14 is provided with a circumferential groove-like constricted portion 20 near the upper end portion, and a flange portion is integrally formed at the opening peripheral edge portion on the upper side in the axial direction. Further, the peripheral wall portion of the constricted portion 20 is a tapered cylindrical portion that gradually increases in diameter toward the upper opening side. And the 1st attachment member 12 is arrange | positioned on the substantially identical center axis | shaft spaced apart in the axial direction upper direction of the 2nd attachment member 14, and the outer peripheral surface of the inverted truncated cone shape of the 1st attachment member 12 And the inner peripheral surface of the tapered cylindrical portion of the second attachment member 14 are opposed to each other.

  Further, the main rubber elastic body 16 has a substantially frustoconical shape, and the first mounting member 12 is fixed in an embedded state at the center portion of the small-diameter side end thereof, while the large-diameter side end thereof is fixed. The inner peripheral surface of the upper end portion of the second mounting member 14 is fixed to the outer peripheral surface of the part. The opposing surface between the outer peripheral surface of the first mounting member 12 and the inner peripheral surface of the upper end portion of the second mounting member 14 is elastically connected by the main rubber elastic body 16. The main rubber elastic body 16 is an integrally vulcanized molded product having the first and second mounting members 12 and 14. A seal rubber layer 22 covering substantially the entire surface is integrally formed with the main rubber elastic body 16 so as to extend downward from the main rubber elastic body 16 on the inner peripheral surface of the second mounting member 14. .

  In addition, a thin rubber diaphragm 24 as a flexible film is disposed in the lower opening portion of the second mounting member 14. A ring-shaped fitting 26 is vulcanized and bonded to the outer peripheral surface of the diaphragm 24, and the fitting 26 is fitted and fixed to the lower opening of the second mounting member 14. The lower opening of the mounting member 14 is fluid-tightly sealed with a diaphragm 24.

  As a result, a liquid-sealed region in which the inside of the second mounting member 14 is sealed with respect to the external space and filled with an incompressible sealed fluid between the opposing surfaces of the main rubber elastic body 16 and the diaphragm 24. Is defined.

  In addition, a partition member 28 is accommodated in the liquid seal region. Each of the partition members 28 has an approximately disc-shaped upper partition plate 30 and a lower partition plate 32 overlapped with each other, and has a disc shape with a predetermined thickness as a whole. The partition member 28 is fitted to the second mounting member 14 and assembled in a state where the partition member 28 extends in a direction perpendicular to the axis at an axially intermediate portion. The inner peripheral surface is fitted and fixed via a seal rubber layer 22.

  As a result, the liquid seal region is partitioned on both the upper and lower sides by the partition member 28, and a part of the wall portion is configured by the main rubber elastic body 16 above the partition member 28, and the main rubber elasticity when the vibration is input. A main liquid chamber 34 is formed in which pressure fluctuation is caused based on elastic deformation of the body 16. Also, below the partition member 28, a part of the wall portion is constituted by the diaphragm 24, and the change in volume is easily allowed, so that the pressure fluctuation is avoided and the sub liquid chamber 36 is maintained at substantially atmospheric pressure. Is formed.

  Further, the partition member 28 is formed with an orifice passage 38 extending in the circumferential direction at a predetermined length in the outer circumferential portion, and fluid flow through the orifice passage 38 is allowed between the main liquid chamber 34 and the sub liquid chamber 36. It has come to be. In the present embodiment, the upper groove 40 that opens to the outer peripheral surface in the outer peripheral portion of the upper partition plate 30 and extends a little less than one round in the circumferential direction, and the upper groove 40 that opens to the upper surface in the outer peripheral portion of the lower partition plate 32 opens in the circumferential direction. Are connected to each other at one end in the circumferential direction, so that an orifice passage 38 extending as a whole with a length of less than one round is formed.

  In particular, in the present embodiment, a large-diameter circular recess 44 that opens upward is formed in the central portion of the upper orifice passage 38. Further, an opening 46 on the main liquid chamber 34 side of the orifice passage 38 is formed to open upward in a thick portion on the outer peripheral side of the circular recess 44. Thereby, the circular recess 44 is formed at a position off the opening 46 of the orifice passage 38 and at a position off the extension line in the opening direction of the opening 46 of the orifice passage 38.

  Furthermore, in this embodiment, the upper surface of the partition member 28 that is a surface exposed to the main liquid chamber 34 is a low adhesion energy surface 48 over substantially the entire surface. The low adhesion energy surface 48 is a surface having a water contact angle of 90 degrees or more, and can be realized by molding the upper partition plate 30 with a hydrophobic material (nonpolar substance), for example. Preferably, the low adhesion energy surface 48 can be formed by forming a coating layer of a hydrophobic material on the surface of the upper partition plate 30. By adopting the coating layer in this manner, a large degree of freedom in selecting the material of the upper partition plate 30 is ensured, and the low adhesion energy surface 48 can be easily obtained by subsequent processing.

  Examples of the coating layer that provides the low adhesion energy surface 48 include tetrafluoroethylene resin (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer resin (FEP), and tetrafluoroethylene / barfluoroalkyl vinyl ether. Fluorine resins and silicone resins such as copolymer resin (PFA), trifluorinated resin (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), and PTFE / PFA composite paint have excellent durability. Since it can provide good hydrophobicity, it is preferably employed. In particular, such fluorine-based resins and the like exhibit water repellency as well as oil repellency, and thus can be more suitably employed in the present invention.

  That is, as the sealed fluid filled in the liquid sealing region, in general, a polar (hydrophilic) liquid made of an organic solvent such as ethylene glycol, propylene glycol, alkylene glycol, polyalkylene glycol, etc. is adopted in addition to water. It is preferable that a polar substance is added as a solute as the solvent using such a polar liquid as needed. However, depending on the required characteristics, nonpolar (hydrophobic) substances may be added to such polar liquids, and in any case, even when a nonpolar solvent is used as the sealing fluid, It becomes possible to obtain the low adhesion energy surface 48 by using the system resin.

  And in this embodiment, what contains 0.03-61200 volume% of dissolved gas is employ | adopted as an enclosed fluid in the environment of normal temperature and atmospheric pressure. As the dissolved gas, in addition to air, at least one selected from the group consisting of ammonia, hydrogen chloride, carbon dioxide, nitrogen monoxide, oxygen, carbon monoxide, hydrogen, nitrogen, neon, and helium is preferably employed. In particular, air or a dissolved gas having a higher hydrophilicity than air is preferably employed, thereby improving the affinity for a solvent when a polar liquid is used as an encapsulated fluid, and a low adhesion energy surface. This is also advantageous for increasing the contact angle of the bubbles with respect to 48 to make the bubbles close to a spherical shape and hardly disappear.

  In addition, increasing the dissolved gas content is effective in preventing cavitation, and therefore the provided sealed fluid is much larger than the gas content that naturally dissolves at room temperature and atmospheric pressure. It is desirable to set the dissolved gas amount. Specifically, for example, a sealed fluid containing 0.10% by volume or more of dissolved gas at room temperature and atmospheric pressure can be suitably used.

  Here, in order to easily realize a large dissolved amount of gas, it is also effective to add a substance that generates gas in a solvent in a solid or liquid state. Specifically, powders (powder and powder) of ammonium chloride, ammonium sulfate, ammonium hydroxide, ammonium hydrogen carbonate, and ammonium carbonate are preferable. In addition, sodium hydrogen carbonate, potassium hydrogen carbonate, hypochlorous acid At least one foamable or non-foamable powder selected from the group consisting of sodium, magnesium carbonate, calcium carbonate, dry ice and calcium peroxide can be employed as an additive. In addition, by adding calcium hydroxide together with ammonium chloride, ammonia is easily generated in the solvent, so that ammonia can be dissolved in the solvent.

  In the engine mount 10 having the structure as described above, when vibrations in the vertical direction are mainly input between the first mounting member 12 and the second mounting member 14 in a mounted state on the vehicle, A fluid flow through the orifice passage 38 is generated based on a relative pressure fluctuation caused between the chamber 34 and the sub liquid chamber 36. Then, by utilizing the resonance action of the fluid flowing through the orifice passage 38, for example, a desired vibration-proofing effect such as a high damping effect against the engine shake is exhibited.

  By the way, when an impact load is input to the engine mount 10 when the vehicle gets over a step, an excessive pressure change is abruptly generated in the main liquid chamber 34, and abnormal noise caused by cavitation due to the pressure change tends to be a problem. Here, in the engine mount 10 of the present embodiment, since the dissolved gas is contained in the sealed fluid, aeration occurs before reaching the cavitation, and bubbles of the dissolved gas appear.

  Then, since the amount of pressure change in the main liquid chamber 34 is absorbed and alleviated by the air bubbles that appear, the significant pressure drop in the main liquid chamber 34 is reduced, and as a result, cavitation is prevented, and consequently An effect of reducing abnormal noise and vibration, which are considered to be caused by cavitation, is exhibited. In particular, in the engine mount 10 according to the present embodiment, the low adhesion energy surface 48 having a small contact angle with water is formed on the inner surface of the main liquid chamber 34 where bubbles of dissolved gas are likely to appear. The bubbles appearing on 48 are more effectively maintained, and the effect of preventing cavitation due to the relaxation of the pressure change in the main liquid chamber 34 is more stably exhibited.

  That is, as shown in FIG. 2A, the contact angle θ of the bubble 50 that appears on the low adhesion energy surface 48 is a value corresponding to the physical properties and surface state of the low adhesion energy surface 48. To do. And in this embodiment, the contact angle (theta) of this bubble 50 is also enlarged because it is set as the low adhesion energy surface 48 to which water repellency was provided by setting the water contact angle to 90 degree | times or more. Particularly preferably, the contact angle θ of the bubbles 50 on the low adhesion energy surface 48 in the sealed fluid is set to be 90 degrees or more.

As a result, the bubbles 50 appearing on the low adhesion energy surface 48 are formed into a lens shape or a spherical shape, and, for example, as shown in FIG. 2B, a flat expanded shape with a small contact angle θ ′. Compared to the bubble 50 ', the appearing bubble 50 is easily maintained stably. Note that the lens-shaped or nearly spherical bubble 50 shown in FIG. 2 (a) is more susceptible to pressure fluctuations in the main liquid chamber 34 than the flat expanded bubble 50 'shown in FIG. 2 (b). The reason why the liquid does not easily disappear and is easily maintained stably is, for example, as shown in FIG. 2C, the bubble internal pressure Pi and the external pressure obtained from the Young-Laplace equation represented by the following equation: When the relationship between Po and the interfacial tension of the bubble surface and ΔP determined from the bubble shape is expressed by the following equation, the bubble 50 is easily maintained and grown.
Pi> Po + ΔP
ΔP = γ (1 / r1 + 1 / r2)
However, γ is the interfacial tension, r1 and r2 are the main radii of curvature of the ellipse, and in the case of a sphere, r1 = r2 = minimum value.
Therefore, it is presumed that the bubble 50 has a smaller surface area when it is closer to a sphere, thereby reducing the area of the external pressure and reducing the overall external pressure acting on the bubble 50.
It is also presumed that the low critical interfacial tension of the low adhesion energy surface 48 contributes.

  The correctness of such a theory can be confirmed by observing the generation and disappearance of bubbles in a vibration experiment using a transparent model of the engine mount. In addition, from the experimental data to be described later, by maintaining the bubbles 50, it is possible to confirm the cavitation preventing effect due to the relaxation of the pressure change of the main liquid chamber 34 by the bubbles 50.

  Further, in the present embodiment, the low adhesion energy surface 48 where the bubbles 50 are expressed and held in an attached state is at a position away from the opening 46 to the main liquid chamber 34 of the orifice passage 38 and the opening of the orifice passage 38. Since the low adhesion energy surface 48 is formed in a recessed shape that opens into the main liquid chamber 34 and is formed in a region out of the fluid inflow / outflow direction through the portion 46, the main liquid is input during vibration input. The influence of the fluid flow generated in the chamber 34 is avoided, and the bubbles 50 can be maintained more stably in the fluid retention region. That is, when the bubbles 50 leave the low adhesion energy surface 48, the plurality of bubbles 50 may be combined and become larger, and the impact generated when the larger bubbles disappear will cause new problems such as abnormal noise. However, such problems can be effectively avoided by holding the bubbles 50 on the low adhesion energy surface 48.

  By the way, the low adhesion energy surface 48 can be formed with an arbitrary shape, size, number, etc. at an arbitrary position on the surface exposed to the main liquid chamber 34. It may be formed to extend to the inner surface of the equilibrium chamber 36.

  Specifically, for example, like the engine mount 50 shown in FIG. 3 as the second embodiment, the partition member 28 is provided with a cup-shaped unevenness 51 that opens into the main liquid chamber 34, and the center of the upper surface of the partition member 28. A small central recess 52 may be formed in the region, and the central recess 52 may be used as a retention region, and the inner surface of the central recess 52 may be used as a low adhesion energy surface 48. In addition, in the following embodiment, about the member and site | part made into the same structure as 1st embodiment, those detailed description is given by attaching | subjecting the code | symbol same as 1st embodiment in a figure. Omitted.

  In the present embodiment, the orifice passage 38 that opens upward is located below the opening to the main liquid chamber 34, and is located sufficiently away from the opening of the orifice passage 38 even in the direction perpendicular to the axis. Since the staying region is formed with a recess that opens to the bottom, the air bubbles developed in the low adhesion energy surface 48 can be more effectively maintained without being adversely affected by the fluid flow in the main liquid chamber 34. .

  Further, for example, as shown in FIG. 4 as the third embodiment, the inner surface of the central recess 52 and the inner surface of the recess 44 formed on the outer peripheral side are both low adhesion energy surfaces 48. Alternatively, it may be formed with a structure of a staying region. This makes it possible to form the low adhesion energy surface 48 with a larger area.

  Furthermore, FIG. 5 shows an engine mount 60 as a fourth embodiment of the present invention. The engine mount 60 of the present embodiment is different from the engine mount 10 of the first embodiment in that another aspect of the orifice passage formed in the partition member 28 is combined with another aspect of the recess as a staying region. Adopted.

  Specifically, in the partition member 28 of the present embodiment, the upper groove 40 in the upper partition plate 30 extends with a length of one turn or less in the circumferential direction, as shown in FIGS. A recess 62 is formed in a portion where the upper groove 40 is not formed between both ends in the circumferential direction of the upper groove 40. Both end portions in the circumferential direction of the upper groove 40 are connected to one of the lower groove 42 and the main liquid chamber 34 to form an orifice passage 38 as in the first embodiment.

  The recess 62 does not communicate with the upper groove 40 and is formed independently from the orifice passage 38. The recess 62 is opened to the main liquid chamber 34 to form the main liquid chamber 34 including the inside of the recess 62, and the inner surface of the recess 62 is a part of the inner surface of the main liquid chamber 34. Is configured. The inner surface of the recess 62 is a low adhesion energy surface 64. In the present embodiment, as in the first embodiment, the inner surface of the large-diameter circular recess 44 formed at the center of the upper surface of the partition member 28 is also a low adhesion energy surface 48.

  Furthermore, the recess 62 opens upward into the main liquid chamber 34, while the opening 46 of the orifice passage 38 to the main liquid chamber 34 penetrates the inner peripheral wall of the recess 48 and is perpendicular to the axis. It is formed toward. As a result, the opening of the recess 62 is formed at a position outside the opening direction of the orifice passage 38 to the main liquid chamber 34, and the fluid pressure recess 62 flows through the opening 46 of the orifice passage 38. Thus, the stay region is effectively formed in the recess 62. In particular, in the present embodiment, as shown in the plan view of FIG. 8, the recess 62 is formed in a region within 90 degrees with respect to the opening 46 of the orifice passage 38 in the circumferential direction around the mount center axis. As a result, a recess 62 is formed at a position that is substantially completely out of the direction of fluid flow into and out of the main liquid chamber 34 of the orifice passage 38.

  Therefore, in the engine mount 60 of the present embodiment, the low adhesion energy surface 64 is formed by the recess 62 in such a manner that the adverse effect due to the fluid flow in the main liquid chamber 34 can be further avoided. Based on the bubbles appearing on the energy surface 64, the effect of preventing cavitation by relaxing the pressure change in the main liquid chamber 34 can be more effectively exhibited.

  FIG. 9 shows an engine mount as a fifth embodiment of the present invention. The engine mount according to the present embodiment is the engine mount 10 according to the first embodiment, in which dissolved gas to the sealed fluid is realized with a specific addition structure.

  Specifically, in the present embodiment, in the manufacturing process of the engine mount 10, the initial structure in which the composite 66 for gas mixing is accommodated in the liquid sealing region so that the composite 66 is immersed in the sealed fluid. It is said. Such a composite 66 dissolves by being exposed to the encapsulating fluid to a solid or gel-like dispersion medium that substantially disappears when it is decomposed or melted by immersion in the encapsulating fluid, and generates gas in a foamed or non-foamed state. It is a composite structure in which the generated powder or powdery dispersoid is included. In the present invention, the term “dispersed” refers to a composite in which the surface of the dispersoid is covered with the dispersion medium regardless of the size of the powder that is the dispersoid and the state of dispersion or uneven distribution of the dispersoid in the dispersion medium. The state contained in the body 66 is said.

  As the dispersion medium in the composite 66, for example, gelatin, pectin, agar, or the like can be adopted. Particularly, a pectin, agar, or the like that is difficult to melt at room temperature and is maintained in a gel form is suitable. Moreover, as a dispersoid in the composite_body | complex 66, ammonium chloride, ammonium sulfate, etc. can be employ | adopted, for example. Since the composite 66 is configured with the dispersoid coated on the surface with a dispersion medium, the powder or powdery dispersoid that generates gas can be easily handled as a block state. Become. Further, by predefining the amount of the dispersoid contained in one of the composites 66 having a predetermined size, the target gas amount can be accurately and easily contained in the sealed fluid. The target engine mount 10 can be manufactured stably.

  That is, the engine mount of the present embodiment is a partition member separately prepared by, for example, immersing an integrally vulcanized molded product of the main rubber elastic body 16 including the first and second mounting members 12 and 14 in an enclosed fluid. 28 and the diaphragm 24 are sequentially fitted and assembled in the integral vulcanization molded product of the main rubber elastic body 16 in the sealed fluid, and then the lower opening portion of the second mounting member 14 is drawn and sealed. By doing so, the engine mount 10 can be manufactured together with the filling of the sealed fluid. In this case, for example, the composite body 66 as described above is accommodated in the integrally vulcanized molded product of the main rubber elastic body 16 before the partition member 28 and the diaphragm 24 are assembled. The engine mount 10 of this embodiment can be obtained.

  In the engine mount manufactured as described above, the composite 66 is accommodated in the main liquid chamber 34 as shown in FIG. 9 when the manufacture is completed. The dispersion medium 66 is melted and the dispersoid is exposed to the sealed fluid. As a result, the dispersion medium is gasified in the liquid-sealed region having a sealed structure and is contained in the sealed fluid as a dissolved gas.

  Therefore, according to such an engine mount manufacturing method, it becomes possible to easily and accurately contain dissolved gas in the sealed fluid filled in the liquid seal region, and the target engine mount according to the present invention can be obtained. It can be manufactured more stably.

  Incidentally, in order to confirm the effect of the present invention, the engine mount 10 having the structure according to the first embodiment is manufactured, and the engine mount 10 is set in a test apparatus 68 as shown in FIG. Anti-vibration characteristics were measured. The test apparatus 68 sets the engine mount 10 between the base member 70 and the vibration exciter 72, and a load sensor 74 transmits a transmission load transmitted from the vibration exciter 72 to the base member 70 via the engine mount 10. It comes to detect in. The detection signal from the load sensor 74 detected a vibration load in the target frequency range through a bypass filter (500 Hz). In this experiment, a pressure sensor was installed in the main liquid chamber 34, and the pressure change in the main liquid chamber 34 was measured together with the change in the transmission load with respect to the vibration displacement of the vibration tool 72. The obtained results are shown in [Table 1] below, and the measurement results in Example 7 and Comparative Example 1 in [Table 1] are shown in FIGS.

  From these measurement results, a low-adhesive energy surface having a contact angle with water of 90 degrees or more is used as the main liquid while using a sealed fluid containing 0.03% by volume or more of dissolved gas at room temperature and normal pressure according to the present invention. By providing in the chamber, it can be seen that the pressure drop of the main liquid chamber when an excessive vibration load is input can be reduced, and the occurrence of abnormal noise due to the impact load can be suppressed. Note that the amount (wt%) of the ammonium chloride powder that generates dissolved gas in the sealed fluid employed in Examples 5 and 9 is 230% by volume in terms of gas volume%. In addition, as a result of further studies including such measurement results, in the present invention, it is desirable that the amount of dissolved gas is 100% by volume or more, whereby the transmission load caused by cavitation is reduced to the conventional structure. It is possible to keep it to 30% or less as compared with products.

10, 50, 60: Engine mount 12: First mounting member 14: Second mounting member 16: Main rubber elastic body 28: Partition member 34: Main liquid chamber 36: Sub liquid chamber 38: Orifice passage 46: (Orifice Openings 44, 52, 62: passage 48, 64: recess 48, 64: low adhesion energy surface 66: composite 66 (for gas incorporation)

Claims (13)

A main liquid chamber in which pressure fluctuation is caused based on deformation of the main rubber elastic body at the time of vibration input; a sub liquid chamber in which relative pressure fluctuation is generated between the main liquid chamber at the time of vibration input; In a fluid-filled vibration isolator having an orifice passage that allows the flow of a sealed fluid between a liquid chamber and a sub-liquid chamber,
The sealed fluid contains 0.03% by volume or more of dissolved gas at room temperature and atmospheric pressure,
A fluid-filled vibration damping device, wherein a low adhesion energy surface having a contact angle with water of 90 degrees or more is provided on an inner surface of the main liquid chamber.   2. The fluid-filled vibration isolator according to claim 1, wherein the content of the dissolved gas in the sealed fluid is 61200 volume% or less in an environment of normal temperature and atmospheric pressure.   The fluid-filled vibration isolator according to claim 1 or 2, wherein the low adhesion energy surface is formed by a surface treatment layer provided on a surface of a member constituting the main liquid chamber.   One side of the partition member supported by the second mounting member by connecting the first mounting member and the second mounting member attached to each one of the members constituting the vibration transmission system with the main rubber elastic body Forming the main liquid chamber in which a part of the wall portion is formed of the main rubber elastic body, forming the equilibrium chamber on the other side of the partition member, and further, forming the main liquid chamber in the partition member The fluid-filled vibration isolator according to any one of claims 1 to 3, wherein the low-adhesion energy surface is provided on a surface exposed to water.   The fluid-filled vibration isolator according to any one of claims 1 to 5, wherein the low adhesion energy surface is provided at a position away from an opening of the orifice passage to the main liquid chamber.   The fluid according to any one of claims 1 to 5, wherein a fluid retention region having irregularities is provided on an inner surface of the main liquid chamber, and the low adhesion energy surface is formed on an inner surface of the fluid retention region. Enclosed vibration isolator.   The fluid-filled vibration isolator according to claim 6, wherein the fluid retention region is formed with a concave shape opening in the main liquid chamber.   The powdery body that is gasified by being exposed to the sealed fluid is sealed in a storage region of the sealed fluid, and the gasified powdery body is the dissolved gas. The fluid-filled vibration isolator according to any one of the above.   A dispersoid composed of the powdery body is a gas-mixing composite configured by coating the surface of the dispersoid with a solid or gel-like dispersion medium that melts in the sealed fluid. The fluid-filled vibration isolator according to claim 8 enclosed in the accommodation area.   The fluid-filled vibration isolator according to claim 8 or 9, wherein the solid or gel dispersion medium is one of gelatin, pectin, and agar.   The fluid-filled vibration isolator according to any one of claims 8 to 10, wherein the dispersoid made of the powdery material includes at least one of ammonium chloride, ammonium sulfate, ammonium hydroxide, ammonium hydrogen carbonate, and ammonium carbonate. .   12. The contact angle with respect to air bubbles in the sealed fluid of bubbles appearing by aeration due to a pressure drop in the main liquid chamber on the low adhesion energy surface is 90 degrees or more. The fluid-filled vibration isolator described in 1. A main liquid chamber in which pressure fluctuation is caused based on deformation of the main rubber elastic body at the time of vibration input; a sub liquid chamber in which relative pressure fluctuation is generated between the main liquid chamber at the time of vibration input; A fluid-filled vibration isolator manufacturing method comprising an orifice passage that allows the flow of a sealed fluid between a liquid chamber and a sub-liquid chamber,
Forming a low adhesion energy surface having a water contact angle of 90 degrees or more in at least a part of the inner surface of the main liquid chamber;
A step of preparing a gas-mixing composite in which a surface of a dispersoid composed of a powdery substance that is gasified by being exposed to the sealed fluid is coated with a solid or gel-like dispersion medium that melts in the sealed fluid. When,
Containing the gas-mixing composite in the containment fluid containment region and filling the containment fluid with the containment fluid; and
A fluid-sealed vibration isolator characterized by containing the gasified powdery body in the enclosed area filled in the containing area as a dissolved gas of the enclosed fluid at a concentration of 0.03% by volume or more. Manufacturing method.

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