JP2013133862A - Liquid sealed vibration control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent liquid sealed vibration control device, effectively suppressing cavitation causing generation of abnormal noise, without impairing vibration control effect.SOLUTION: The liquid sealed vibration control device includes: a liquid sealing space partitioned into a main liquid chamber 25 and a sub liquid chamber 26 which communicate with each other through an orifice 27; a vulcanized rubber molding 22 forming a part of the liquid sealing space; and a first holding member 20 and a second holding member 21 holding the vulcanized rubber molding 22. Mixed liquid is used as liquid P sealed in the liquid sealing space. The mixed liquid is made by mixing first liquid made from a polar organic solvent, second liquid made from polar oil having compatibility with the first liquid and interfacial activity performance, and water containing dissolved gas.

Description

  The present invention relates to a liquid-filled vibration isolator used for automobiles, industrial machines and the like.

  Liquid-sealed devices have been used as anti-vibration devices such as engine mounts, transmission mounts, suspension bushings, and motor mounts used in automobiles and industrial machines. For example, as shown in FIG. 4, the engine mount includes an upper holding member 1 attached to an engine that is a vibration source, and a lower holding member 2 attached to a vehicle body, a frame, and the like. It is integrated through the body 4. A diaphragm 5 is attached to the lower holding member 2, and a liquid sealed space for storing the liquid P in a sealed state is formed between the diaphragm 5 and the vulcanized rubber molded body 3. Further, the liquid sealed space is divided into two upper and lower chambers, a main liquid chamber 9 and a sub liquid chamber 10, by a partition member 8 in which an orifice 7 is formed, and the liquid P passes through the orifice 7 between the two chambers. To flow through. In addition, 11 and 12 are bolt screws for attachment, respectively (for example, refer patent document 1).

  According to this configuration, even if the vulcanized rubber molded body 3 receives the vibration of the engine, it is transmitted to the vehicle body side by the vibration absorbing action by its own elasticity and the flow action of the liquid P in the liquid sealed space. Vibration is damped.

  By the way, in recent years, technological innovation in the automobile industry has been remarkable, and extremely quiet running is being realized compared to the past, but if the engine is subject to large vibrations due to the unevenness of the road surface, the main rubber elastic body will be greatly elastically deformed Abnormal noise and vibration caused by the shock wave generated when cavitation is generated in the pressure receiving chamber due to cavitation and the shock wave generated when the bubble disappears is transmitted to the vehicle because the pressure in the pressure receiving chamber rapidly decreases significantly. Is a problem.

  Therefore, as a method for suppressing the occurrence of such cavitation, a device such as a relief valve is provided to reduce the pressure difference between the main liquid chamber 9 and the sub liquid chamber 10, or a high vapor pressure (= A method (for example, refer to Patent Document 2) or the like for suppressing the pressure drop in the main liquid chamber 9 by adding a liquid having a low boiling point and vaporizing the high vapor pressure liquid under a negative pressure has been proposed.

JP 2005-337348 A International Publication No. 2009/154222

  However, when a device such as the relief valve is provided, if the valve is opened to suppress cavitation, the pressure difference between the main liquid chamber 9 and the sub liquid chamber 10 becomes small, and the damping performance is exhibited while passing through the orifice 7. Since the amount of movement of the liquid P is reduced, there is a problem that the damping performance is lowered, and the anti-vibration effect that is the original purpose cannot be sufficiently obtained.

  In addition, in the method of adding a high vapor pressure liquid described in Patent Document 2, the boiling point of the liquid to be added is low. The added liquid is boiled, and a large amount of gas is resident in the liquid chamber, thereby causing a reduction in vibration-proof performance and expansion and rupture of the diaphragm, resulting in a problem in product function.

  The present invention has been made in view of such circumstances, and is an excellent liquid-filled vibration isolator capable of effectively suppressing cavitation causing abnormal noise without impairing the vibration isolating effect. The purpose is to provide.

  In order to achieve the above object, a liquid-filled vibration isolator according to the present invention includes a liquid sealed space for containing a liquid in a sealed state, and a partition for partitioning the liquid sealed space into a plurality of chambers in a state where they are communicated with each other through an orifice. A vulcanized rubber molded body that forms at least a part of the liquid sealed space, and a holding member that holds the vulcanized rubber molded body, and the vibration transmitted to the vulcanized rubber molded body is A liquid-filled vibration isolator configured to be attenuated by elastic deformation of the vulcanized rubber molded body itself and liquid flow between the chambers, wherein the liquid includes a first liquid made of a polar organic solvent, and the first liquid A mixed liquid obtained by mixing a second liquid composed of polar oil having compatibility with one liquid and having surface activity and water containing dissolved gas is used, and by vaporization or liquefaction of the dissolved gas, Up A configuration that the pressure fluctuations in the liquid sealing space due to elastic deformation of the vulcanized rubber molding is enabled relaxation.

  The inventors of the present invention have conducted research on a method for suppressing cavitation in a liquid-filled vibration isolator without impairing the vibration isolating effect. As a result, it was found that when the gas generated under negative pressure is dispersed into a plurality of bubbles, the generation of large bubbles is suppressed, and cavitation due to the burst of large bubbles does not occur. As a result of further research, in order to disperse a plurality of gases in order to suppress the generation of large bubbles, conventional polar organic solvents such as ethylene glycol are compatible with this, and also have surface active performance. It has been found that when a polar oil having a water content is blended as the second liquid, the surface tension of the entire liquid is lowered, and bubbles generated in the liquid are divided into a plurality of parts. When the dissolved gas contained in water is used as the gas source for generating the bubbles, the dissolved gas dissolved in the water is vaporized when the liquid sealed space becomes negative pressure, and when the negative pressure is eliminated, the vaporized dissolved gas is dissolved. Since the gas is dissolved again in the water, the pressure fluctuation in the liquid sealed space is effectively relieved, and an excellent cavitation suppressing effect is obtained, and the present invention has been achieved.

  That is, the liquid-filled vibration isolator of the present invention includes a first liquid made of a polar organic solvent and a polar oil that is compatible with the first liquid and has a surface-active performance as the liquid sealed in the device. Since the mixed liquid formed by mixing the second liquid and the water containing the dissolved gas is used, the surface tension of the entire liquid is lower than that of the conventional liquid and is derived from the dissolved gas contained in the water under a negative pressure. Since the bubbles are generated in a state of being divided into a plurality of portions and the generation of large bubbles that cause cavitation is suppressed, an excellent cavitation suppressing effect can be obtained. And, since the generation of noise due to cavitation is suppressed without impairing the original vibration isolation performance associated with the fluidity of the device, it is possible to keep quiet in the environment where the vibration isolation device is installed, such as the car body. it can.

  In the present invention, in particular, the first liquid is composed of at least one of ethylene glycol and propylene glycol, and the second liquid is at least one of polyether oil, polyether-modified silicone oil, and vinyl oil. A liquid-filled vibration isolator, which is a kind of polar oil, is particularly excellent in cavitation suppression effect because the generated gas is divided into a plurality of liquids and easily grows under negative pressure.

  Furthermore, in the present invention, in particular, the liquid is a mixed liquid obtained by blending 0.1 to 80 parts by weight of the second liquid and 0.1 to 30 parts by weight of water with respect to 100 parts by weight of the first liquid. Since the liquid-sealed vibration isolator is a more preferable liquid property, it has an excellent cavitation suppressing effect.

  Further, among the present invention, in particular, the liquid-filled vibration isolator in which the water contains 0.03 to 3.0% by volume of dissolved gas in an environment of normal temperature and atmospheric pressure is a liquid sealed space. Since sufficient gas can be obtained from the water to relieve the pressure fluctuation inside, it is preferable.

It is a longitudinal cross-sectional view which shows one embodiment of this invention. It is typical explanatory drawing of the method of measuring the transmission load of an engine mount. (A) is a diagram which shows the anti-vibration performance of the Example goods of this invention, (b) is a diagram which shows the anti-soaking performance of a comparative example goods. It is sectional drawing which shows the conventional liquid enclosure type vibration isolator.

  Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to this embodiment.

  An embodiment of the present invention is shown in FIG. This liquid-filled vibration isolator is attached to a vehicle body, a frame, or the like via a first holding member 20 attached to an engine as a vibration source via a bolt (not shown) and a predetermined attachment member (not shown). A substantially cylindrical second holding member 21 to be attached is integrated via a vulcanized rubber molded body 22. In addition, a diaphragm 23 is attached in a liquid-tight state inside the lower end opening of the second holding member 21, and a liquid-sealed liquid P is accommodated between the vulcanized rubber molded body 23 and the diaphragm 23 in a sealed state. A space is formed.

  The liquid sealed space is partitioned into two upper and lower chambers of a main liquid chamber 25 and a sub liquid chamber 26 via a partition member 24, and the main space is divided by an orifice 27 provided at the peripheral edge of the partition member 24. The liquid chamber 25 and the sub liquid chamber 26 are communicated with each other.

  Therefore, according to the above configuration, when the vulcanized rubber molded body 22 receives the vibration of the engine, it is transmitted to the vehicle body side by the vibration absorbing action due to its own elasticity and the flow action of the liquid P in the liquid sealed space. The vibrations that occur are attenuated to a very low level, and excellent vibration-proofing performance is exhibited.

  In addition, in this apparatus, as the liquid P to be sealed in the liquid sealed space, a first liquid made of a polar organic solvent and a second liquid made of polar oil that is compatible with the first liquid and has surface activity ability. And a mixed liquid obtained by mixing water containing dissolved gas. This is a major feature of the present invention.

  As the polar organic solvent used as the first liquid, ethylene glycol (hereinafter referred to as “EG”) alone, propylene glycol (hereinafter referred to as “PG”) alone used as a liquid sealed in a liquid filled type vibration isolator. Alternatively, a mixed liquid thereof or the like can be used. In addition, glycol solvents such as butyl diglycol, methyl triglycol, butyl triglycol, and methyl polyglycol, or water and other polar fluids can be used. Especially, it is suitable to use the liquid mixture of EG and PG, and the thing whose mixing ratio (EG: PG) is 50: 50-90: 10 is especially suitable.

  Examples of polar oils that are used as the second liquid and that are compatible with the first liquid and have surface-active performance include polyether oils, polyether-modified silicone oils, and vinyl oils. . These may be used alone or in combination of two or more. These need not be easily vaporized, and those having an average molecular weight of 2000 to 8000 are usually preferably used. Of these, polyether-modified silicone oil is particularly preferable from the viewpoints of compatibility with the first liquid and surface active performance.

  The phrase “having compatibility” means that the second liquid has an affinity for the first liquid, and the liquid obtained by mixing the two becomes a uniform one-phase liquid. In addition, the above-mentioned “having surface active performance” means that the molecule has a hydrophilic part and a lipophilic part, and has the ability to lower the interfacial tension at the interface of two liquids that do not melt together. Say.

  The water used together with the first liquid and the second liquid may be any kind of water, industrial water, ground water, river water, etc., but it contains dissolved gas to some extent in the water. There must be. This is because the dissolved gas in the water is vaporized or liquefied according to the pressure fluctuation in the liquid enclosure space, thereby reducing the pressure fluctuation. Note that the “water” is water that is intentionally blended separately from the first liquid and the second liquid, unlike the “water arbitrarily used as the first liquid” described above.

  Therefore, the dissolved gas content of water used in the present invention is desirably 0.03 to 3.0% by volume with respect to water in an environment of normal temperature and atmospheric pressure. That is, if it is less than 0.03% by volume, the above-described pressure fluctuation relaxation action cannot be expected so much, and conversely, it is not easy to contain a gas in excess of 3.0% by volume under atmospheric pressure.

  The above “normal temperature” means a temperature in which neither water is heated nor cooled (usually 25 ° C.), and “atmospheric pressure” means that water is particularly pressurized or depressurized. The pressure in the absence.

  Examples of the gas that becomes the dissolved gas include various gases such as oxygen, carbon dioxide, nitrogen, argon, helium, and ammonia. The gas is not limited to a gas that is intentionally dissolved, but may be a gas in which a gas such as air is dissolved in water prepared as a raw material. However, if the dissolved gas content is low and the pressure fluctuation mitigating action as described above seems to be too small, the raw water is subjected to aeration such as bubbling to increase the dissolved gas content. It is desirable to mix with the 1st liquid and the 2nd liquid.

  In the case of using a mixture of a plurality of liquids such as EG and PG as the first liquid and including a dissolved gas by slightly entraining the gas during the mixing, the dissolved gas is also the above-mentioned Like water dissolved gas, vaporization and liquefaction are repeated along with pressure fluctuations in the liquid sealed space, which is suitable for relaxation.

  The mixing ratio of the first liquid, the second liquid, and water may be set to 0.1 to 80 parts by weight of the second liquid and 0.1 to 30 parts by weight of water with respect to 100 parts by weight of the first liquid. Is preferred. That is, when the amount of the second liquid is less than the above range, the surface tension of the entire liquid P is not lowered so much that a plurality of bubbles are hardly generated. Conversely, the second liquid is less than the above range. This is because if the amount is large, the ratio of the first liquid that is a generation source of bubbles and water decreases, and it becomes difficult to obtain a sufficient pressure fluctuation mitigating action.

  Further, if the amount of water is less than the above range, the amount of dissolved gas derived from water becomes insufficient, and it becomes difficult to obtain a sufficient pressure fluctuation mitigating action. Conversely, if the amount of water is more than the above range, The boiling point of the encapsulated liquid is lowered, which may make it difficult to use in a high temperature environment such as in an engine room.

  In addition to the first liquid, the second liquid, and water, the liquid P composed of the mixed liquid of the first liquid, the second liquid, and water is added with an antifoaming agent, an antioxidant, or the like as an optional component. can do. Furthermore, in order to assist the pressure fluctuation mitigating action by the dissolved gas in water, a substance capable of generating a gas by thermal decomposition or the like, such as sodium hydrogen carbonate or ammonium hydrogen carbonate, can be added.

  As described above, the present invention uses the special liquid P as the liquid P sealed in the liquid sealed space. Therefore, the surface tension of the entire sealed liquid P is lower than that in the conventional case, and the liquid P is immersed in water under a negative pressure. Since a plurality of bubbles derived from the dissolved gas contained are generated in a state of being separated in the liquid, an excellent cavitation suppressing effect can be obtained. And, since the generation of noise due to cavitation is suppressed without impairing the original vibration isolation performance associated with the fluidity of the device, it is possible to keep quiet in the environment where the vibration isolation device is installed, such as the car body. it can.

  Next, an example of a method for producing the engine mount will be described.

  First, a mold for molding the vulcanized rubber molded body 22 is prepared, and the first holding member 20 and the second holding member 21 are set at predetermined positions of the mold. The first holding member 20, the second holding member 21, and the vulcanized rubber molded body 22 are integrated by heating after filling the unvulcanized rubber composition that is the material of the vulcanized rubber molded body 22. To do. Next, a diaphragm 23 that has been heat-molded in advance is prepared, and the first holding member 20, the second holding member 21, and the vulcanized rubber molded body 22 are integrated in the liquid tank in which the liquid P is stored. The partition member 24 and the diaphragm 23 are fitted from the lower end opening of the second holding member 21 and attached to a predetermined position, and then taken out from the liquid tank. In this way, the liquid P is sealed between the vulcanized rubber molded body 22 and the diaphragm 23. Thereafter, the lower end portion of the second holding member 21 is caulked to completely seal the liquid P. In this way, the engine mount can be manufactured.

  The above example is one example in which the liquid-filled vibration isolator of the present invention is applied to an engine mount. However, the engine mount is a suspended type and an upright mounted type. There is no problem. Further, the present invention can be applied to various vibration isolators such as an engine mount, an automobile suspension bush, and a motor mount.

  Next, examples will be described together with comparative examples.

[Examples 1 to 9, Comparative Example 1]
As the liquid P sealed in the liquid sealed space, those having the compositions shown in Tables 1 and 2 below are used. An engine mount similar to that shown in FIG. 1 was produced.

  As shown in FIG. 2, the obtained engine mount A is attached to a vibration device 30, a mount displacement is input by simulating vehicle mounting, a load at the time of vibration is read by a load sensor 31, and a high-pass filter ( The transmission load (N) was measured through 500 Hz). And the transmission load of each Example 1-9 goods when the transmission load of 1 product of a comparative example was set to 100 was calculated, and the result was combined with the following Table 1 and Table 2, and was shown.

  From the above results, it can be seen that the products of Examples 1 to 9 have a smaller transmission load than the product of Comparative Example 1 and have excellent vibration isolation performance.

  For reference, the measurement result of the product of Example 2 is shown in FIG. 3A, and the measurement result of the product of Comparative Example 1 is shown in FIG.

  The present invention is a liquid-filled vibration isolator such as an engine mount, a mission mount, a suspension bush, and a motor mount used for automobiles, industrial machines, etc., and in particular, the generation of abnormal noise due to cavitation is effectively suppressed. It can be used for anti-vibration devices.

20 First holding member 21 Second holding member 22 Vulcanized rubber molded body 23 Diaphragm 24 Partition member 25 Main liquid chamber 26 Sub liquid chamber 27 Orifice P Liquid

Claims (4)

  Liquid sealed space for storing liquid in a sealed state, a partition for partitioning the liquid sealed space into a plurality of chambers in communication with each other through an orifice, and a vulcanized rubber molded body forming at least a part of the liquid sealed space And a holding member for holding the vulcanized rubber molded body, and vibration transmitted to the vulcanized rubber molded body is attenuated by elastic deformation of the vulcanized rubber molded body itself and liquid flow between the chambers. A liquid-filled vibration isolator configured to perform a first liquid composed of a polar organic solvent and a polar oil that is compatible with the first liquid and has surface-active performance. A liquid mixture obtained by mixing two liquids and water containing dissolved gas is used, and the pressure in the liquid sealed space accompanying the elastic deformation of the vulcanized rubber molded body by vaporization or liquefaction of the dissolved gas. Change fluid-filled vibration damping device characterized in that it enabled relaxation.   2. The first liquid is made of at least one of ethylene glycol and propylene glycol, and the second liquid is at least one polar oil of polyether oil, polyether-modified silicone oil, and vinyl oil. Liquid filled vibration isolator.   The liquid according to claim 1 or 2, wherein the liquid is a mixed liquid obtained by blending 0.1 to 80 parts by weight of the second liquid and 0.1 to 30 parts by weight of water with respect to 100 parts by weight of the first liquid. Enclosed vibration isolator.   The liquid-filled vibration isolator according to any one of claims 1 to 3, wherein the water contains 0.03 to 3.0% by volume of dissolved gas in an environment of normal temperature and atmospheric pressure.

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