JP5384242B2 - Vibration isolator - Google Patents

Description

  The present invention relates to a fluid-filled vibration isolator that prevents transmission of vibration from a member that generates vibration, and more particularly, to a vibration isolator that is suitably used for an engine mount of an automobile.

  For example, in a vehicle such as a passenger car, an anti-vibration device serving as an engine mount is disposed between an engine serving as a vibration generating unit and a vehicle body serving as a vibration receiving unit. In the vibration isolator, when the inner cylinder and the outer cylinder vibrate in the axial direction due to vibration generated from the engine, the vibration is attenuated by liquid movement between the first main liquid chamber and the sub liquid chamber. ing. For example, in the vibration isolator described in Patent Document 1, in addition to the above structure, two pressure receiving liquid chambers (liquid chambers) are arranged in a direction (axial direction) perpendicular to the axial direction, and these pressure receiving liquids The chamber communicates with the auxiliary liquid chamber, and the vibration in the axial direction is attenuated by the liquid movement between the plurality of liquid chambers.

  By the way, in the vibration isolator having a structure capable of vibration attenuation in two directions (axial direction and axial direction) in this way, it is desirable to reduce the dynamic spring constant for high-frequency vibration in each of the two directions. It is.

JP 2006-125617 A

  In consideration of the above facts, the present invention provides a vibration isolator capable of reducing the dynamic spring constant in these two directions in a vibration isolator that attenuates vibration not only in the axial direction but also in the direction perpendicular to the axial direction. It is an object to obtain a device.

In the first aspect of the present invention, the first mounting member is formed in a cylindrical shape and connected to one of the vibration generating portion and the vibration receiving portion, and is connected to the other of the vibration generating portion and the vibration receiving portion, and the first mounting member A second mounting member disposed on the inner peripheral side of the member, an elastic body disposed between the first mounting member and the second mounting member and connecting the first mounting member and the second mounting member; The liquid is sealed between the partition member and the partition member constituting the first main liquid chamber in which the liquid is sealed between the elastic body and the internal volume is changed with the elastic deformation of the elastic body. A diaphragm member that constitutes a sub liquid chamber that is enclosed and whose internal volume changes in response to a change in the liquid pressure, and a first that enables the liquid to move between the first main liquid chamber and the sub liquid chamber. A recess that forms a liquid chamber between the restriction passage and the first mounting member provided in the elastic body; A chamber, a partition wall for partitioning the second main liquid chamber a plurality of which are arranged in a direction intersecting the axial direction of the first attachment member, enabling the movement of the liquid between the plurality of the second main liquid chamber with each other And a pressure difference reducing means for reducing a pressure difference between the first main liquid chamber and the second main liquid chamber.

  In this vibration isolator, when vibration is transmitted from the vibration generating portion to one of the first mounting member and the second mounting member, the vibration isolator is disposed between the first mounting member and the second mounting member to connect them. The elastic body is elastically deformed. Then, the vibration is absorbed by the vibration absorbing action based on the internal friction or the like of the elastic body, and the vibration transmitted to the vibration receiving portion side is reduced.

  The first main liquid chamber configured between the elastic body and the partition member and the sub liquid chamber configured between the partition member and the diaphragm member are respectively filled with liquid, and further, the first The movement of the liquid between the main liquid chamber and the sub liquid chamber is enabled by the first restriction passage. Therefore, when the first mounting member and the second mounting member vibrate in the axial direction and the internal volume of the first main liquid chamber changes with the elastic deformation of the elastic body, a part of the liquid is between the sub-liquid chamber. Therefore, the input vibration (in the main amplitude direction) can be absorbed.

Further, in this vibration isolator, a liquid chamber is formed between the concave portion provided in the elastic body and the first mounting member, and the liquid chamber intersects the axial direction of the first mounting member by the partition wall. Are partitioned into a plurality of second main liquid chambers. And the movement of the liquid between several 2nd main liquid chambers is enabled by the 2nd restriction | limiting channel | path. Therefore, when the first mounting member and the second mounting member vibrate in a direction orthogonal to the axial direction (axial direction) , the liquid moves between the plurality of second main liquid chambers. Thereby, the input vibration can be absorbed even in the direction perpendicular to the axis.

  In addition, in this vibration isolator, the pressure difference between the first main liquid chamber and the second main liquid chamber is reduced by the pressure difference reducing means. In other words, a so-called “pressure release” is performed on the first main liquid chamber and the second main liquid chamber by the pressure difference reducing means. For this reason, when high-frequency vibrations (for example, vibrations such that the first restriction passage does not function as a liquid movement passage) are input in the axial direction, the first main liquid chamber and the second main liquid chamber are caused by the pressure difference reducing means. And the pressure difference is reduced. Thereby, the dynamic spring constant in the axial direction can be lowered. Similarly, when high-frequency vibration is input in the axial direction, the pressure difference between the first main liquid chamber and the second main liquid chamber is reduced by the pressure difference reducing means. Can be lowered.

  According to a second aspect of the present invention, in the first aspect of the present invention, the pressure difference reducing means is provided in the partition wall.

  Thus, when the pressure difference reducing means is provided in the partition wall, it is not necessary to provide the pressure difference reducing means in a part or member other than the partition wall. Therefore, it is possible to maintain the original function as a vibration isolator.

  According to a third aspect of the present invention, in the second aspect of the present invention, the pressure difference reducing means is formed in the partition wall through the central portion in the thickness direction of the partition wall through the first main liquid chamber. Is formed as a thin wall portion on both sides of the lightening portion.

  Therefore, the pressure difference between the first main liquid chamber and the second main liquid chamber, that is, the pressure fluctuation can be absorbed by the deformation of the thin wall portion. Since the pressure difference reduction means can be configured simply by forming a thin wall by forming a thin wall in the partition wall, the effect on the overall performance of the vibration isolator is reduced, and the original vibration isolation performance of the vibration isolator can be maintained high. .

  The invention according to claim 4 is the invention according to claim 1, wherein the elastic body is gradually expanded in diameter while being extended from the second mounting member toward the partition member, and has a truncated cone shape. A conical section that partitions the first main liquid chamber and the second main liquid chamber and elastically deforms and attenuates the vibration by relative vibration in the axial direction between the first mounting member and the second mounting member;

  A lid portion extending radially outward from the second mounting member on the opposite side of the partition member as viewed from the conical portion, and serving as a lid for the liquid chamber, and the pressure difference reducing means includes the conical portion It is comprised by the thin part which made thin locally.

  The first main liquid chamber can be formed between the elastic member and the partition member by forming a truncated cone-shaped conical portion. The conical portion is elastically deformed as a main subject of deformation during the relative vibration between the first mounting member and the second mounting member, thereby providing a vibration isolation effect. And since the cone part which is the main body of this deformation has secured a large volume as an elastic body, while being able to exhibit a high anti-vibration effect, durability becomes high. Moreover, the liquid chamber (second main liquid chamber) between the concave portion of the elastic body and the first mounting member can be reliably maintained by configuring the liquid chamber lid by the lid portion extended from the elastic body.

  Further, the pressure difference reducing means can be configured with a simple structure in which the conical portion is locally thinned to form the thinned portion. Moreover, the thin portion is locally formed in the conical portion, and the thickness of the conical portion is maintained in portions other than the thin portion. That is, it is possible to secure the thickness of the conical portion as the main subject of deformation and to exert a high vibration-proof effect.

  According to a fifth aspect of the present invention, in the first aspect of the present invention, the second attachment member is formed with a communication hole through which the first main liquid chamber and the second main liquid chamber communicate. The pressure difference reducing means is formed of a thin film portion that is formed by the elastic body and partitions the communication hole into the first main liquid chamber side and the second main liquid chamber side.

  Therefore, the pressure difference between the first main liquid chamber and the second main liquid chamber is reduced by deformation of the thin film portion that partitions the communication hole into the first main liquid chamber side and the second main liquid chamber side. As the pressure difference reducing means, it is sufficient to form a communication hole in the second mounting member and to form a thin film portion for partitioning the communication hole, so that the influence on the performance of the entire vibration isolation device is reduced. High anti-vibration performance can be maintained.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the partition member is not deformed by a pressure difference between the first main liquid chamber and the sub liquid chamber. It is comprised by the highly rigid partition member.

  Thus, by making a partition member into a highly rigid partition member, when the pressure difference of a 1st main liquid chamber and a subliquid chamber arises, the inadvertent deformation | transformation of a partition member can be suppressed. As a result, an inadvertent drop in the pressure of the first main liquid chamber due to the deformation of the partition member is also suppressed, so that the pressure difference between the first main liquid chamber and the second main liquid chamber is reduced by the pressure difference reducing means. It becomes possible to reduce it reliably.

  Moreover, since it is not necessary to provide the partition member with a member (for example, a membrane) for reducing the pressure difference between the first main liquid chamber and the sub liquid chamber, a sufficiently long first restriction passage is formed in the partition member. It becomes possible to do.

  According to a seventh aspect of the present invention, in the sixth aspect of the invention, in the high-rigidity partition member, the first restriction passage is formed relatively on the inner peripheral side, and the second restriction passage is formed on the outer peripheral side. Has been.

  As a result, both the first restriction passage and the second restriction passage can secure a sufficient length.

  Since the present invention is configured as described above, the dynamic spring constant in these two directions can be lowered in the vibration isolator that attenuates vibration not only in the axial direction but also in the direction perpendicular to the axial direction.

It is a perspective view which shows the structure of the vibration isolator which concerns on 1st Embodiment of this invention partially fractured | ruptured along an axial direction. It is a top view which shows the structure of the vibration isolator which concerns on 1st Embodiment of this invention. It is the III-III sectional view taken on the line of FIG. 2 which shows the structure of the vibration isolator which concerns on 1st Embodiment of this invention. FIG. 4 is an axial cross-sectional view at a position different from FIG. 3 showing the configuration of the vibration isolator according to the first embodiment of the present invention. It is sectional drawing of the horizontal direction which shows the structure of the vibration isolator which concerns on 1st Embodiment of this invention. It is a perspective view which partially fractures | ruptures and shows the internal structure of the vibration isolator which concerns on 1st Embodiment of this invention along an axial direction. It is a perspective view which shows the orifice cylindrical body which comprises the vibration isolator which concerns on 1st Embodiment of this invention. It is a graph which shows the relationship between the input frequency which acts on the axial direction of a vibration isolator, the dynamic spring constant in the amplitude of +/- 0.3mm, and the loss coefficient in the amplitude of +/- 1.0mm. It is a graph which shows the relationship between the input frequency which acts on the axial direction of a vibration isolator, the dynamic spring constant in the amplitude of +/- 0.3mm, and the loss coefficient in the amplitude of +/- 1.0mm. It is a perspective view which partially fractures | ruptures and shows the structure of the vibration isolator which concerns on 2nd Embodiment of this invention along an axial direction. It is a perspective view which partially fractures | ruptures and shows the structure of the vibration isolator which concerns on 3rd Embodiment of this invention along an axial direction.

  FIG. 1 shows a vibration isolator 12 according to a first embodiment of the present invention. The vibration isolator 12 is used as an engine mount in an automobile, for example. An engine serving as a vibration generating unit is supported on a vehicle body serving as a vibration receiving unit. In the drawings, symbol S indicates the axial center of the vibration isolator 12. The direction along the axial center S is the axial direction of the vibration isolator 12, and the direction orthogonal to the axial center S (axial direction) is prevented. The radial direction of the vibration device 12 is assumed.

  As shown in detail in FIGS. 3 and 4, the vibration isolator 12 includes an outer cylinder 14 formed in a substantially cylindrical shape. At a position below the center in the axial direction of the outer cylinder 14, a reduced diameter portion 14 </ b> S that is reduced in diameter through a stepped portion 14 </ b> D is formed. Also, a substantially cylindrical covering rubber 16 is vulcanized and coated over substantially the entire inner peripheral surface of the outer cylinder 14. From the vicinity of the lower end of the covering rubber 16, a diaphragm 18 is integrally extended radially inward.

  The diaphragm 18 is a film-like member that is curved so that a central portion thereof is convex upward, and forms a sub liquid chamber 30 between the diaphragm 18 and the orifice cylinder 26 described later. The sub liquid chamber 30 is expanded and contracted by the deformation of the diaphragm 18 so that the volume thereof is changed. The outer cylinder 14 and the covering rubber 16 constitute a first mounting member 20 according to the present invention.

  A plurality of (for example, three) leg portions (not shown) extend radially outward from the outer cylinder 14, and the vibration isolator 12 is attached to the vehicle body by inserting the bolts into the bolt insertion holes at the tips of the leg portions. Attached to. Instead of (or in combination with) the legs, a bracket may be fixed to the outer cylinder 14 and the outer cylinder 14 may be attached to the vehicle body using the bracket.

  A cylindrical inner cylinder 22 is disposed inside the outer cylinder 14 so as to be positioned at the axis S. The lower bottom portion of the inner cylinder 22 is closed, but the upper bottom portion is opened and a female screw 22M is formed on the inner periphery. An engine-side bolt or the like is screwed into the female screw 22M, for example, so that the engine is supported by the vibration isolator 12. Note that the vibration isolator 12 of the present embodiment also has an effect of attenuating vibration in the axial direction, but the axis of the inner cylinder 22 is the axis of the outer cylinder 14 when no vibration is input. Is consistent with

  A rubber elastic body 24 is disposed between the inner cylinder 22 and the outer cylinder 14 (covering rubber 16), and the inner cylinder 22 and the outer cylinder 14 are connected by the rubber elastic body 24. Further, an orifice cylindrical body 26 and a partition disk 32 are arranged between the rubber elastic body 24 and the diaphragm 18 or the covering rubber 16.

  The rubber elastic body 24 has a truncated cone-shaped rubber main body portion 24 </ b> B that is extended from the lower portion of the inner cylinder 22 toward the orifice cylindrical body 26 and gradually expanded in diameter. Further, from the upper side of the rubber body 24B, the diameter gradually increases while extending toward the upper end of the outer cylinder 14 (that is, toward the side opposite to the partition disk 32 when viewed from the rubber body 24B). The lid portion 24L is provided. A recess 24H is provided between the rubber main body 24B and the lid 24L, and a liquid chamber 40 according to the present invention is provided between the recess 24H and the first mounting member 20 (covering rubber 16). ing. By making the rubber main body 24B into such a shape, the volume can be increased, and the anti-vibration effect at the time of elastic deformation can be exhibited highly and the durability is improved.

  The orifice cylindrical body 26 has a substantially disc-shaped orifice disc portion 26D, and a substantially cylindrical orifice cylinder portion 26E that is erected upward from the outer periphery of the orifice disc portion 26D. The outer edge portion of the lower surface of the orifice cylindrical portion 26E is supported on the covering rubber 16 by the step portion 14D. A partition disk 32 is supported above the orifice disk part 26D, and the first main liquid chamber 28 is interposed between the partition disk 32 and the rubber main body part 24B of the rubber elastic body 24. It is configured. The first main liquid chamber 28 is filled with a liquid such as ethylene glycol or silicon oil. Further, a sub liquid chamber 30 is formed between the orifice disk portion 26 </ b> D and the diaphragm 18. Similarly to the first main liquid chamber 28, the sub liquid chamber 30 is filled with a liquid such as ethylene glycol or silicon oil. In particular, since a part of the sub liquid chamber 30 is constituted by the diaphragm 18, the deformation of the diaphragm 18 brings the sub liquid chamber 30 to a state close to atmospheric pressure (so that inflow and outflow of fluid occur). Is possible.

  A spiral first orifice 36 is formed in the orifice disk portion 26D. The upper end of the first orifice 36 communicates with the first main liquid chamber 28 through a communication hole 38 formed in the partition disk 32, and the lower end of the first orifice 36 opens downward and communicates with the sub liquid chamber 30. ing. As a result, the first orifice 36 is a flow path that allows the liquid to move between the first main liquid chamber 28 and the sub liquid chamber 30. In particular, the length and cross-sectional area of the first orifice 36 as a flow path are set corresponding to vibration in a specific frequency range (for example, shake vibration), and the first main liquid chamber 28, the sub liquid chamber 30, It is adjusted so that this vibrational energy can be absorbed by the liquid movement.

  As will be described later, in this embodiment, when the relative fluctuation in the pressure of the first main liquid chamber 28 and the sub liquid chamber 30 occurs at a high frequency that cannot be absorbed by the fluid movement through the first orifice 36, the thin wall A conventional membrane is not provided because the structure is configured to relieve the pressure fluctuation by deforming the portion 42U. Further, the partition disk 32 and the orifice disk part 26D have such a rigidity that they do not inadvertently deform even if the pressure of the first main liquid chamber 28 changes. Thus, since the first main liquid chamber 28 and the second main liquid chamber are partitioned by a highly rigid member without using the conventional membrane, the pressure of the first main liquid chamber 28 due to deformation of the membrane or the like. The decline of is suppressed.

  As can be seen from FIGS. 2, 4, and 5, two partition walls 42 that partition the liquid chamber 40 in the direction perpendicular to the axis are formed between the rubber main body 24 </ b> B and the lid 24 </ b> L. The partition wall 42 has a symmetrical shape about the axis S and is continuous from the lid portion 24L to the rubber main body portion 24B. Further, as shown in FIGS. 4 and 5, the tip end of the partition wall 42 (the end portion farthest from the axis S) is in pressure contact with the inside of the first mounting member 20 (covering rubber 16). The partition wall 42 divides the liquid chamber 40 into two second main liquid chambers 40A and 40B. As can be seen from FIG. 4, the upper portion of the partition wall 42 extends upward from the lid portion 24L.

  As shown in FIG. 1, a flat cylindrical holding cylinder 44 is disposed on the outer peripheral surface of the rubber main body 24 </ b> B of the rubber elastic body 24 and is vulcanized and bonded. The holding cylinder 44 is pressure-bonded to the inner peripheral surface of the orifice cylindrical portion 26E of the orifice cylindrical body 26, so that inadvertent misalignment between the rubber elastic body 24 and the orifice cylindrical body 26 is suppressed. A ring-shaped holding ring 46 is disposed on the outer peripheral surface of the lid portion 24L of the rubber elastic body 24 and is vulcanized and bonded. The lower surface of the holding ring 46 is in close contact with the upper surface of the outer cylinder 14, and the lid 24 </ b> L of the rubber elastic body 24 is fixed to the outer cylinder 14 by fixing the holding ring 46 to the outer cylinder 14. . As shown in FIG. 5, the holding cylinder 44 and the holding ring 46 are connected and integrated by a plurality of support plates 48 formed therebetween. The holding cylinder 44, the holding ring 46 and the support plate 48 are integrally formed of metal or the like, and the rubber elastic body 24 is vulcanized and integrated inside the holding cylinder 44 and the holding ring 46. The member integrated in this way is press-fitted inside the first mounting member 20 (covering rubber 16).

  Two concave grooves 50 are formed on the outer peripheral surface of the orifice cylindrical portion 26 </ b> E of the orifice cylindrical body 26. As shown in detail in FIG. 7, each of the concave grooves 50 has one end (a part of the upper end) communicated with the second main liquid chambers 40A and 40B by the communication part 50A and the other end (a part of the lower end). The secondary liquid chamber 30 communicates with the communication part 50B. In the portion where the concave groove 50 is formed, two second orifices corresponding to the second main liquid chambers 40A and 40B, respectively, between the orifice cylindrical portion 26E and the first mounting member 20 (covering rubber 16). 52A and 52B are configured, and the second orifices 52A and 52B are flow paths that allow the fluid to move between the corresponding second main liquid chambers 40A and 40B and the sub liquid chamber 30, respectively. The lengths and cross-sectional areas of the second orifices 52A and 52B as flow paths are set corresponding to vibrations in a specific frequency range, and the liquid movement between the second main liquid chambers 40A and 40B and the sub liquid chamber 30 is performed. Therefore, the vibration energy is adjusted so as to be absorbed. In particular, the set frequency in the second orifices 52A and 52B is higher than the set frequency in the first orifice 36.

  And in the orifice cylindrical body 26 of this embodiment, the 1st orifice 36 is formed in the inner peripheral side, and 2nd orifice 52A, 52B is formed in the outer peripheral side. In this way, by forming two orifices separately on the inner side and the outer side in the circumferential direction, the degree of freedom of the mutual shape of the orifices increases, for example, ensuring a sufficient length as a fluid flow path, etc. Is possible.

  As shown in detail in FIGS. 4 to 6, each of the partition walls 42 has a thinned portion 54 at the center in the thickness direction. That is, the rubber constituting the rubber elastic body 24 does not exist in the central portion in the thickness direction in the portion related to the partition wall 42. The thinned portion 54 is opened to the lower side, that is, toward the first main liquid chamber 28, and is a recess when viewed from the first main liquid chamber 28. On the other hand, the lightening portion 54 is not opened upward and is closed by rubber. As can be seen from FIG. 4, the thinned portion 54 is formed to be substantially square when the partition wall 42 is viewed from the front.

  By forming such a thinned portion 54 in the partition wall 42, the partition wall 42 is formed with thin wall portions 42U on both sides of the thinned portion 54 (both sides in the thickness direction of the partition wall 42, see FIG. 5). Yes. The first main liquid chamber 28 and the second main liquid chambers 40A and 40B are separated by the thin wall portion 42U in the portion where the lightening portion 54 is formed. Further, in the partition wall 42, a portion other than the thin wall portion 42U forms a relatively thick wall portion 42A. The thick wall portion 42A has a shape that continues from the upper end (the lid portion 24L) to the lower end (the rubber main body portion 24B) on the inner side and the outer side of the partition wall 42 in the radial direction.

  The thickness of the thin wall portion 42U is such that the relative fluctuation in pressure between the first main liquid chamber 28 and each of the second main liquid chamber 40A and the second main liquid chamber 40B is a high frequency (for example, a first value) When the frequency is such that the orifice 36 is clogged), the thin wall portion 42U is deformed so that this pressure fluctuation can be alleviated. On the other hand, the thickness of the thick wall portion 42A is such that the partition wall 42 is securely pressed against the covering rubber 16 so that the space between the partition wall 42 and the covering rubber 16 is liquid-tight, and the lid portion 24L is reliably supported. At the same time, when the inner cylinder 22 and the outer cylinder 14 move relative to each other, they are elastically deformed so that a resistance against the relative movement is exhibited, and the energy of the relative movement can be effectively dissipated by the internal friction. ing.

  Next, the operation of the vibration isolator 12 of this embodiment will be described.

  When the engine is activated, vibration from the engine is transmitted to the rubber elastic body 24 through the inner cylinder 22. At this time, the rubber elastic body 24 acts as a vibration absorber, and the input vibration is absorbed by a damping action due to internal friction or the like accompanying the deformation of the rubber elastic body 24.

  Here, the main vibrations input from the engine to the vibration isolator 12 are vibrations (main vibrations) generated when the piston in the engine reciprocates in the cylinder, and the rotation speed of the crankshaft in the engine changes. Vibration (sub-vibration) generated by the operation. In addition, vibrations input to the vibration isolator 12 from the vehicle body side include inputs close to the main vibration and the sub vibration described above. The rubber elastic body 24 can be absorbed by a damping action due to internal friction or the like, regardless of whether the input vibration is a main vibration or a secondary vibration. Actually, a vibration obtained by combining the main vibration and the sub-vibration acts on the vibration isolator 12, but for the sake of convenience, the behavior of the vibration isolator 12 will be described separately for each vibration. In this vibration isolator 12, as an example of the arrangement direction, the main amplitude direction is aligned with the axial direction of the vibration isolator 12, and the sub-amplitude direction is aligned with the axial direction of the vibration isolator 12. doing.

  First, the case where the main vibration is input to the vibration isolator 12 will be described with reference to the graph shown in FIG. This graph shows an example of the relationship between the dynamic spring constant and the loss coefficient of the rubber elastic body 24 with respect to the frequency of the input vibration acting in the axial direction. In this graph, the thick line indicates the dynamic spring constant, and the thin line indicates the loss coefficient. Moreover, in each, the continuous line has shown the vibration isolator 12 of this embodiment, and the dashed-two dotted line has shown the vibration isolator of the comparative example. In the vibration isolator of the comparative example, a portion corresponding to the thin wall portion 42U of the present embodiment is not formed on the partition wall 42, but the other structure is the same as that of the vibration isolator 12 of the present embodiment.

  In the vibration isolator 12 of the present embodiment, the first main liquid chamber 28 communicates with the sub liquid chamber 30 through the first orifice 36. Therefore, when main vibration is input to the inner cylinder 22 from the engine side, the rubber elastic body 24 is elastically deformed along the main amplitude direction, and the internal volume of the first main liquid chamber 28 is expanded or contracted. As a result, the liquid flows between the first main liquid chamber 28 and the sub liquid chamber 30 through the first orifice 36 in synchronization with the input vibration.

  Here, the path length and the cross-sectional area of the first orifice 36 are set to correspond to the frequency of a specific input vibration (for example, shake vibration). Therefore, a resonance phenomenon (liquid column resonance) occurs in the liquid that flows between the first main liquid chamber 28 and the sub liquid chamber 30 through the first orifice 36. The input vibration in the main amplitude direction can be particularly effectively absorbed by the pressure change and viscous resistance of the liquid accompanying the liquid column resonance.

  In particular, in the present embodiment, the first main liquid chamber 28 and the second main liquid chambers 40A and 40B are separated by the thin wall portion 42U. Therefore, when the frequency of the input vibration in the main amplitude direction is high, if the first orifice 36 is clogged and it is difficult for the liquid to flow, the thin wall portion 42U is deformed as the pressure of the first main liquid chamber 28 changes. . In the present embodiment, since the second main liquid chambers 40A and 40B communicate with the sub liquid chamber 30 through the second orifices 52A and 52B, the second main liquid chambers 40A and 40B and the sub liquid chamber 30 are connected. Liquid column resonance also occurs due to the second orifices 52A and 52B. Then, an increase in the dynamic spring constant associated with an increase in the hydraulic pressure in the first main liquid chamber 28 can be suppressed. This point can also be understood by comparing a thick solid line (this embodiment) and a two-dot chain line (comparative example) in the graph shown in FIG. That is, in the relatively high frequency region (approximately 13 Hz or more), the dynamic spring constant is lower in this embodiment than in the comparative example. In addition, in this embodiment, the loss coefficient is higher in the region where the frequency is approximately 16 Hz or higher than in the comparative example. Thus, in the present embodiment, the dynamic spring constant of the rubber elastic body 24 is kept low by performing so-called “pressure release” even when such high-frequency vibration is input in the main amplitude direction. The high-frequency vibration can be effectively absorbed by the elastic deformation of 24 or the like.

  As described above, in the structure in which the second main liquid chambers 40A and 40B communicate with the sub liquid chamber 30 through the second orifices 52A and 52B, for example, the first orifice 36 and the second orifices 52A and 52B, respectively. By appropriately setting the flow path cross-sectional area and the flow path length, it is possible to cause a peak of the loss coefficient at two locations, a relatively low frequency area and a high frequency area. For example, in the thin solid line of the graph shown in FIG. 8 (this embodiment), a first peak in a low frequency region (approximately 10 Hz) and a second peak in a high region (approximately 18 Hz) are generated. . Also in the thin two-dot chain line (comparative example), a first peak in a low frequency region (approximately 12 Hz) and a second peak in a high region (approximately 17 Hz) are generated. As can be seen by comparing the solid line of the thin line (this embodiment) and the two-dot chain line of the thin line (comparative example), the frequency of the loss coefficient at the first peak is higher in this embodiment than in the comparative example. Is also low.

  Next, the case where the secondary vibration is input to the vibration isolator 12 will be described with reference to the graph shown in FIG. This graph shows an example of the relationship between the dynamic spring constant and loss factor of the rubber elastic body 24 with respect to the frequency of the input vibration acting in the axial direction. Also in this graph, the thick line indicates the dynamic spring constant and the thin line indicates the loss coefficient, as in FIG. Moreover, in each, the continuous line has shown the vibration isolator 12 of this embodiment, and the dashed-two dotted line has shown the vibration isolator of the comparative example.

  In the vibration isolator 12 of the present embodiment, the second main liquid chambers 40A and 40B are communicated with the sub liquid chamber 30 through the second orifices 52A and 52B, respectively. Therefore, when a secondary vibration is input to the inner cylinder 22 from the engine side, the rubber elastic body 24 is elastically deformed along the sub-amplitude direction, and the internal volumes of the second main liquid chambers 40A and 40B are expanded and contracted. As a result, the liquid flows between the second main liquid chambers 40A and 40B and the sub liquid chamber 30 through the second orifices 52A and 52B in synchronization with the input vibration.

  Here, the path length and the cross-sectional area in the second orifices 52A and 52B are set so as to correspond to the frequency of a specific input vibration. Therefore, a resonance phenomenon (liquid column resonance) occurs in the liquid that flows between the second main liquid chambers 40A and 40B and the sub liquid chamber 30 through the second orifices 52A and 52B. The input vibration in the sub-amplitude direction can be particularly effectively absorbed by the pressure change and viscous resistance of the liquid accompanying the liquid column resonance.

  In particular, in the present embodiment, the first main liquid chamber 28 and the second main liquid chambers 40A and 40B are separated by the thin wall portion 42U. Therefore, when the frequency of the input vibration in the sub-amplitude direction is high, the thin wall portion 42U of the partition wall 42 vibrates in synchronization with the input vibration. As a result, an increase in the dynamic spring constant associated with a change in the hydraulic pressure in the second main liquid chambers 40A and 40B can be suppressed. That is, in the graph shown in FIG. 9, as can be seen by comparing the thick solid line (this embodiment) and the two-dot chain line (comparative example), the present embodiment is more effective than the comparative example in the region where the frequency is approximately 15 Hz or higher. It can be seen from that the dynamic spring constant is lower. That is, in this embodiment, even when such high-frequency vibration is input in the sub-amplitude direction, so-called “pressure release” is performed to keep the dynamic spring constant of the rubber elastic body 24 low. High frequency vibrations can be effectively absorbed by elastic deformation or the like.

  In the graph shown in FIG. 9, the frequency at the peak of the loss coefficient is the same as that of the present embodiment, as can be seen by comparing the thin solid line (this embodiment) with the thin two-dot chain line (comparative example). Is lower than the comparative example.

  As can be seen from the above description, in this embodiment, the rubber elastic body 24 is obtained by performing so-called “pressure release” in both directions of the main vibration direction (axial direction) and the secondary vibration direction (axial direction). The high-frequency vibration can be effectively absorbed by the elastic deformation of the rubber elastic body 24 and the like.

  Moreover, in the vibration isolator 12 of the first embodiment, the thin wall portion 42U is formed in the partition wall 42 to constitute the pressure and other reducing means of the present invention, and the shape of the rubber main body portion 24B and other parts is formed. Since it is not changed, the influence on the overall performance of the vibration isolator 12 is reduced, and the vibration isolator 12 can maintain the originally required vibration isolating performance.

  Moreover, in the vibration isolator 12 of this embodiment, the pressure fluctuation in the high frequency of the 1st main liquid chamber 28 and the subliquid chamber 30 can be relieve | moderated by the thin wall part 42U so that FIG.1 and FIG.4 etc. may show. Therefore, there is no need to provide a member such as a conventional membrane in the orifice cylindrical body 26. For this reason, since the first orifice 36 can be formed in a portion where the membrane has been disposed in the past, the degree of freedom in setting the shape (channel cross-sectional area and channel length) of the first orifice 36. Becomes higher. In addition, since no membrane is provided, the number of parts is reduced. Since it is not necessary to form a structure for arranging the membrane in the orifice cylindrical body 26, the structure becomes simple and can be manufactured at low cost.

  FIG. 10 shows a vibration isolator 62 according to the second embodiment of the present invention. Hereinafter, in 2nd Embodiment, the same code | symbol is attached | subjected about the same component, member, etc. as 1st Embodiment, and detailed description is abbreviate | omitted.

  In the second embodiment, the thin wall portion 42U is not formed in the partition wall 42. Instead, a circular shape in which both surfaces (upper surface and lower surface) of the rubber main body portion 24B are locally recessed in the rubber main body portion 24B. The recess 64 is formed. That is, the rubber body 24B has a thin portion 24U that is locally thinned by the recess 64, and a portion other than the thin portion 24U becomes a relatively thick portion 24A. Yes. In particular, the thick portion 24A has a shape that continues from the radially inner side (side 9 close to the inner cylinder 22) to the radially outer side (side closer to the covering rubber 16) of the rubber main body portion 24B.

  The thickness of the thin wall portion 24U is determined by the pressure variation caused by the deformation of the thin wall portion 24U when the relative fluctuation of the pressure in the first main liquid chamber 28 and the second main liquid chamber 40A, 40B occurs at a high frequency equal to or higher than a predetermined value. It is decided to be able to relax. On the other hand, the thickness of the thick wall portion 24A is elastically deformed when the inner cylinder 22 and the outer cylinder 14 are moved relative to each other, thereby exerting a resistance against the relative movement and also having the effect of the relative movement energy by the internal friction. It is determined so that the original function as the vibration isolator 62 can be exhibited.

  Therefore, also in the vibration isolator 62 of the second embodiment, the dynamic spring constant when the frequency of the input vibration is high can be reduced in the two directions of the axial direction and the axial direction. In addition, the thickness of the thick portion 24A of the rubber main body portion 24B is an internal friction due to elastic deformation when the inner cylinder 22 and the outer cylinder 14 are relatively moved, effectively dissipating the energy of this relative movement, It is determined so that the original function as the vibration isolator 62 can be exhibited. That is, the thin portion 24U has less influence on the overall performance of the vibration isolator 62, and the vibration isolator 62 can maintain the originally required vibration isolating performance.

  FIG. 11 shows a vibration isolator 82 according to a third embodiment of the present invention. Hereinafter, also in 3rd Embodiment, the same code | symbol is attached | subjected about the same component, member, etc. as 1st Embodiment, and detailed description is abbreviate | omitted.

  In the third embodiment, the thin wall portion 42U is not formed in the partition wall 42, and the thin wall portion 24U is not formed in the rubber main body portion 24B. Instead, a through hole 84 is formed in the inner cylinder 22. Further, a thin film portion 86 is formed in the through hole 84.

  The through hole 84 is formed so as to communicate the first main liquid chamber 28 and the second main liquid chambers 40A and 40B. Then, the rubber constituting the rubber elastic body 24, the first main liquid chamber 28 side, and the second main liquid chambers 40A and 40B side are respectively extended into the through hole 84, and the through hole 84 has a substantially central portion in the longitudinal direction. The thin film portion 86 is formed. The inside of the through hole 84 is separated by the thin film portion 86 into the first main liquid chamber 28 side and the second main liquid chambers 40A and 40B side. The thickness of the thin film portion 86 is determined by the deformation of the thin film portion 86 when the relative fluctuation of the pressure in the first main liquid chamber 28 and the second main liquid chamber 40A, 40B occurs at a high frequency equal to or higher than a predetermined value. It is decided to be able to relax.

  Therefore, also in the vibration isolator 82 of the third embodiment, the dynamic spring constant can be reduced when the frequency of the input vibration is high in the two directions of the axial direction and the axial direction. In addition, since the shape of the rubber body 24B is not changed, the influence on the overall performance of the vibration isolator 82 is reduced, and the vibration isolator 82 can maintain the originally required vibration isolating performance.

  Of course, the pressure difference reducing means according to the present invention is not limited to the thin wall portion 42U, the thin wall portion 24U, and the thin film portion 86 described above. That is, it is only necessary that “pressure release” can be performed between the first main liquid chamber 28 and the second main liquid chambers 40A and 40B.

  Moreover, although the example which formed the thin wall part 42U in both surfaces in each of the two partition 42 was mentioned above, the site | part and number which form the thin wall part 42U are not limited to this. For example, the thin wall portion 42U may be formed only on one partition wall 42.

  In the above description, the vibration isolator 12 has a structure in which the second main liquid chambers 40A and 40B communicate with the sub liquid chamber 30 through the second restriction passage (second orifices 52A and 52B). Other structures can also be employed. For example, instead of the second orifices 52A and 52B, a structure in which a direct communication path that directly communicates the second main liquid chambers 40A and 40B is provided as the second restriction path may be used. Furthermore, as the second restriction passage, the direct communication passage and the second orifices 52A and 52B of the embodiment of the present invention may be used in combination. In particular, when the second main liquid chambers 40A and 40B are communicated with the sub liquid chamber 30, fluid movement between the second main liquid chambers 40A and 40B and the sub liquid chamber 30 is easily caused by expansion and contraction of the sub liquid chamber. Therefore, pressure fluctuation can be absorbed more effectively. In addition, since the second main liquid chambers 40A and 40B are independently communicated with the sub liquid chamber 30, the second main liquid chambers 40A and 40B are not affected by each other and are not affected by each other. Causes liquid movement.

  In the configuration in which the second main liquid chambers 40A and 40B and the sub liquid chamber 30 are communicated with each other, the volume change of the sub liquid chamber 30 occurs, so that the dynamic spring constant in the high frequency region increases as described above. It is assumed that Therefore, the present invention is particularly suitable for a configuration in which the second main liquid chambers 40A, 40B and the sub liquid chamber are communicated.

  In any configuration, in the vibration isolator 12 of the present embodiment, a thin wall for depressurizing the second main liquid chambers 40A and 40B to the partition wall 42 that divides the two second main liquid chambers 40A and 40B. Since the wall portion 42U is formed and it is not necessary to perform processing such as forming a through hole in the inner cylinder 22, it can be manufactured at low cost. Further, in the configuration in which the movable rubber film or the like is provided in the through-hole of the inner cylinder 22, there is a great limitation on the shape and size of the movable rubber film), but when the thin wall portion 42U is provided in the partition wall 42 as in the present embodiment, Since the degree of freedom in shape and size is increased, it is possible to perform pressure relief in the axial direction more reliably.

12 Vibration isolator 14 Outer cylinder 16 Cover rubber 18 Diaphragm 20 First mounting member 22 Inner cylinder (second mounting member)
24 Rubber elastic body 24B Rubber body (conical part)
24L Lid 24A Thick part 24U Thin part 24H Concave 26 Orifice cylinder 28 First main liquid chamber 30 Sub liquid chamber 32 Partition disk (partition member)
36 1st orifice (first restricted passage)
38 communication hole 40 liquid chamber 40A, 40B second main liquid chamber 42 partition wall 42A thick wall portion 42U thin wall portion (pressure difference reducing means)
44 Holding cylinder 46 Holding ring 48 Support plate 50 Groove 52A, 52B Second orifice (second restriction passage)
54 Meat extraction part 62 Vibration isolator 64 Recess 82 Vibration isolator 84 Through hole (communication hole)
86 Thin film part S

Claims (7)

A first mounting member formed in a cylindrical shape and connected to one of the vibration generating portion and the vibration receiving portion;
A second mounting member connected to the other of the vibration generating portion and the vibration receiving portion and disposed on the inner peripheral side of the first mounting member;
An elastic body arranged between the first mounting member and the second mounting member and connecting the first mounting member and the second mounting member;
A partition member that constitutes a first main liquid chamber in which a liquid is enclosed between the elastic body and an internal volume changes with elastic deformation of the elastic body;
A diaphragm member constituting a sub liquid chamber in which a liquid is enclosed between the partition member and an internal volume changes in accordance with a change in liquid pressure;
A first restriction passage that allows liquid to move between the first main liquid chamber and the sub liquid chamber;
A recess which is provided in the elastic body and forms a liquid chamber between the first mounting member;
A partition that divides the liquid chamber into a plurality of second main liquid chambers arranged in a direction intersecting the axial direction of the first mounting member;
A second restriction passage that allows liquid to move between the plurality of second main liquid chambers;
Pressure difference reducing means for reducing a pressure difference between the first main liquid chamber and the second main liquid chamber;
A vibration isolator.   The vibration isolator according to claim 1, wherein the pressure difference reducing means is provided on the partition wall.   The pressure difference reducing means is configured as a thin wall portion on both sides of the thinning portion by forming a thinning portion in the partition that extends from the central portion in the thickness direction of the partition to the first main liquid chamber. The vibration isolator according to claim 2. The elastic body extends from the second mounting member toward the partition member and gradually increases in diameter to have a truncated cone shape, partitioning the first main liquid chamber and the second main liquid chamber and A conical portion that is elastically deformed by an axial relative vibration between the first mounting member and the second mounting member to attenuate the vibration;
A lid portion extending radially outward from the second mounting member on the opposite side of the partition member as seen from the conical portion and serving as a lid of the liquid chamber;
With
The pressure difference reducing means is
The vibration isolator of Claim 1 comprised by the thin part which made the said cone part thin locally. The second mounting member is formed with a communication hole for communicating the first main liquid chamber and the second main liquid chamber,
2. The anti-vibration device according to claim 1, wherein the pressure difference reducing unit is formed of a thin film portion that is formed by the elastic body and partitions the communication hole into the first main liquid chamber side and the second main liquid chamber side. apparatus.   The vibration isolator according to any one of claims 1 to 5, wherein the partition member is configured by a high-rigidity partition member that is not deformed by a pressure difference between the first main liquid chamber and the sub liquid chamber. .   The vibration isolator according to claim 6, wherein in the high-rigidity partition member, the first restricting passage is formed relatively on the inner peripheral side, and the second restricting passage is formed on the outer peripheral side.

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