JP2009058083A - Liquid-filled vibration isolation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid-filled vibration isolation device of a new structure capable of advantageously securing durability of a movable rubber film provided with a short circuit slit for eliminating negative pressure while effectively materializing target vibration isolation performance. <P>SOLUTION: In this vibration isolation device, a liquid pressure absorbing mechanism having the movable rubber film 64 fixedly supported at an outer circumference part thereof by a partition member 44 assembled to the partition member 44, and having pressure of a pressure receiving chamber 78 applied on one surface of the movable rubber film 64 and pressure of the balance chamber 80 applied on another surface, and absorbing pressure fluctuation in the pressure receiving chamber 78 by elastic deformation of the movable rubber film 64 based on differential pressure between the pressure receiving chamber 78 and the balance chamber 80 is constructed, at least one slit 72 is formed on the movable rubber film 64, the slit 72 is retained in a closed state by elasticity of the movable rubber film 64, and a reinforcement protrusion 76 projecting toward a thickness direction both sides of the movable rubber film 65 at is formed at an outside of each end part of the slit 72. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vibration isolator suitably used as, for example, an automobile engine mount or suspension mount, and in particular, a fluid that exhibits a vibration isolating effect based on the flow action of a fluid sealed inside. The present invention relates to a sealed vibration isolator.

  2. Description of the Related Art Conventionally, as a means for supporting one member constituting a vibration transmission system to be anti-vibration connected or anti-vibrated to the other member, for example, the first attachment member is one of the second attachment members having a cylindrical portion. An anti-vibration device having a structure in which the first mounting member and the second mounting member are connected to each other by a main rubber elastic body is known. In addition, in order to obtain an effective anti-vibration effect against vibrations in a specific frequency range in question, a fluid-filled vibration-proof device using the anti-vibration effect based on the fluid action of the fluid enclosed inside is also proposed. ing.

  Specifically, the fluid-filled vibration isolator, for example, connects the first mounting member and the second mounting member to each other with a main rubber elastic body, and supports the partition member with the second mounting member. Then, a part of the wall part forms a pressure receiving chamber composed of the main rubber elastic body on one side of the partition member, and a part of the wall part is on the other side of the partition member. An equilibrium chamber made of a flexible membrane is formed, an incompressible fluid is sealed in the pressure receiving chamber and the equilibrium chamber, and an orifice passage is provided to communicate the pressure receiving chamber and the equilibrium chamber with each other. ing. In such a fluid-filled vibration isolator, when a vibration target vibration is input, between a pressure receiving chamber in which a change in internal pressure is caused by a load input and an equilibrium chamber in which volume change is allowed and maintained at substantially atmospheric pressure. Relative pressure fluctuations are generated. Such relative pressure fluctuations cause fluid flow through an orifice passage that communicates the two chambers with each other, thereby exhibiting an anti-vibration effect based on the fluid flow action. Patent Document 1 (Japanese Patent No. 2805305) shows an example of a fluid-filled vibration isolator.

  However, for example, when the above-described fluid-filled vibration isolator is used as an engine mount for an automobile, vibrations with different frequencies are input depending on the running state of the automobile. While effective vibration isolation effects based on the fluid flow action are exerted on the input, if vibration in a frequency range higher than the tuning frequency is input, the orifice passage is substantially closed and vibration isolation is performed. There was a problem that the performance deteriorated.

  Therefore, in Patent Document 1 and the like, a movable rubber film that partitions the pressure receiving chamber and the equilibrium chamber is provided in the partition member, thereby providing a hydraulic pressure absorption mechanism that releases the hydraulic pressure in the pressure receiving chamber to the equilibrium chamber side. There has been proposed a fluid-filled vibration isolator which is realized by deformation so as to obtain an anti-vibration effect against vibrations in a frequency range higher than the tuning frequency range of the orifice passage.

  By the way, in the conventional fluid-filled vibration isolator, when a large vibration is input between the first mounting member and the second mounting member, there is a possibility that abnormal noise or vibration may occur. For example, when a fluid-filled vibration isolator is used as an engine mount for an automobile, a shocking vibration load is applied between the first mounting member and the second mounting member when traveling on an uneven wavy road. May be generated, causing abnormal noise and vibration that can be felt by the passenger.

  The mechanism for generating such abnormal noise and vibration has not been sufficiently clarified yet, but a shocking vibration load with a large acceleration is input between the first mounting member and the second mounting member. Then, bubbles that are understood as cavitation are generated in the pressure receiving chamber. Then, the water hammer pressure generated when the bubbles collapse is propagated to the first mounting member and the second mounting member, and is transmitted to the vehicle body, which may cause abnormal noise and vibration. It is done. Therefore, it is effective to reduce or avoid abnormal noise and vibration caused by cavitation as soon as possible to eliminate the negative pressure generated in the pressure receiving chamber when an impact load is input.

  Therefore, as one method for reducing or avoiding such noise and vibration, in the fluid filled type vibration isolator disclosed in Patent Document 1, a pressure receiving chamber (first chamber) and an equilibrium chamber (second chamber) are disclosed. ) Has been proposed in which a slit is formed in a movable rubber film (elastic partition wall) arranged so as to partition. In such a fluid-filled vibration isolator described in Patent Document 1, a shocking vibration load is input between the first mounting member and the second mounting member (housing) to generate a negative pressure in the pressure receiving chamber. Then, a notch for short circuit formed in the movable rubber film is opened, and the pressure receiving chamber and the equilibrium chamber are mutually short-circuited through the notch, so that the negative pressure in the pressure receiving chamber is eliminated. .

  However, when the slit is formed in the movable rubber film formed of the rubber elastic body as in the fluid-filled vibration isolator shown in Patent Document 1, the opening and closing of the notch accompanying the elastic deformation of the movable rubber film is repeated. Therefore, the movable rubber film is easily cracked at the end of the slit, and it has been difficult to sufficiently ensure the durability of the movable rubber film. Note that the slits (slits) formed in the movable rubber film must have a high-precision size in order to achieve both the desired anti-vibration effect and the elimination of cavitation. In addition, if a crack occurs at the end of the slit, the intended effect may not be obtained effectively.

Japanese Patent No. 2805305

  Here, the present invention has been made in the background as described above, and the problem to be solved is a short-circuit slit for eliminating negative pressure while effectively realizing the desired vibration isolation performance. It is an object of the present invention to provide a fluid-filled vibration isolator having a novel structure capable of advantageously ensuring the durability of a movable rubber film including

  Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible. Further, aspects or technical features of the present invention are not limited to those described below, but are described in the entire specification and drawings, or an invention that can be understood by those skilled in the art from those descriptions. It should be understood that it is recognized based on thought.

  That is, according to the present invention, the first mounting member and the second mounting member are connected by the main rubber elastic body, and the main rubber elasticity is provided on one side of the partition member supported by the second mounting member. A pressure receiving chamber in which a part of the wall portion is configured by the body is formed, and an equilibrium chamber in which a part of the wall portion is configured by a flexible film is formed on the other side of the partition member. In the fluid-filled vibration isolator in which the pressure receiving chamber and the equilibrium chamber are filled with an incompressible fluid, and an orifice passage that connects the pressure receiving chamber and the equilibrium chamber to each other is formed. A movable rubber film fixedly supported by the partition member is assembled, and the pressure of the pressure receiving chamber is exerted on one surface of the movable rubber film, and the pressure of the equilibrium chamber is exerted on the other surface. Based on the pressure difference between the pressure receiving chamber and the equilibrium chamber A hydraulic pressure absorbing mechanism is configured to absorb pressure fluctuations in the pressure receiving chamber by elastic deformation of the movable rubber film, and at least one slit is formed in the movable rubber film, and the slit is the movable rubber film. The film is held in a closed state by the elasticity of the film, and reinforcing protrusions that protrude toward both sides in the thickness direction of the movable rubber film are formed outside each end of the slit. .

  In such a fluid-filled vibration isolator having a structure according to the present invention, a slit is formed in the movable rubber film that partitions the pressure receiving chamber and the equilibrium chamber, so that a large pressure fluctuation occurs in the pressure receiving chamber due to a shocking large load input. When the pressure is exerted, the slit is opened by the elastic deformation of the movable rubber film, and the pressure receiving chamber and the equilibrium chamber are communicated with each other through the slit with a smaller flow resistance than the orifice passage. As a result, even when a significant negative pressure is generated in the pressure receiving chamber, the negative pressure is eliminated as quickly as possible by the fluid flow through the slit, thereby reducing or avoiding abnormal noise and vibration that may be caused by cavitation. I can do it.

  Here, each end of the slit where cracks are likely to occur due to the concentration of stress accompanying the opening / closing operation of the slit is located on the outside, that is, located on the outside in the extension direction of the slit or away from it. Reinforcing protrusions that protrude toward both sides in the thickness direction of the movable rubber film are formed. Thereby, the occurrence of a crack at the end of the slit can be advantageously avoided, and further progress (extension) of the crack can be effectively prevented at the thickened formation portion of the reinforcing protrusion.

  Furthermore, since the substantial length of the slit can be stably maintained in the initial state, switching between opening and closing of the slit at the set negative pressure can be realized with high accuracy. Therefore, both of the vibration-proofing effect based on the fluid action of the fluid flowing through the orifice passage and the effect of reducing cavitation noise when an impactful load is input can be exhibited effectively.

  In the present invention, the slit refers to a cut formed through the movable rubber film. This notch can take various sizes and shapes, and therefore the shape and size of the slits are not limited at all. For example, such a slit may have an external appearance constituted by a single straight line or curve, or a plurality of straight lines or curves connected at the end or intersecting at an intermediate portion. good. Further, the fact that the slit is held closed by the elasticity of the movable rubber film means that the slit is closed under a stationary state where no pressure fluctuation of the pressure receiving chamber due to external input occurs. In addition, due to the elasticity of the movable rubber film, the deformation of the movable rubber film caused by the action of the hydraulic pressure exerted on the pressure receiving chamber when the vibration in the frequency range (vibration to be damped) is tuned to the orifice passage or the movable rubber film. Therefore, the fluid flow through the slit is suppressed, and the fluid flow amount in the orifice passage is ensured.

  In the fluid-filled vibration isolator according to the present invention, it is desirable that the reinforcing protrusion extends in a direction orthogonal to the extension line of the slit.

  As a result, it is possible to advantageously prevent a crack that proceeds in the direction of the extension line of the slit at the end of the slit from extending so as to bypass the reinforcing protrusion at the portion where the reinforcing protrusion is formed. It can be suppressed.

  Furthermore, in the fluid filled type vibration damping device according to the present invention, it is desirable that the reinforcing protrusion is formed in an annular shape that is continuous in the circumferential direction and is formed so as to surround the outer peripheral side of the slit.

  In this way, by providing an annular reinforcing protrusion that is continuous in the circumferential direction so as to surround the outer periphery of the slit, the reinforcing protrusion can be reliably positioned in the extending direction of the slit, and cracks are more effective. Can be prevented. Although not particularly limited, it is desirable that the reinforcing protrusions extend with a substantially constant cross-sectional shape in the circumferential direction. This makes it possible to prevent the progress of cracks more stably.

  Furthermore, in the fluid-filled vibration isolator having a structure according to the present invention, preferably, the separation distance between the end of the slit and the reinforcing protrusion is 5 mm or less.

  In this way, by setting the separation distance between the slit end and the reinforcing protrusion small, it is possible to more advantageously prevent the occurrence of cracks at the slit ends and to minimize the crack extension. I can do it.

  Further, in the fluid filled type vibration damping device according to the present invention, the film thickness of the movable rubber film in the outer peripheral portion of the reinforcing protrusion may gradually become thinner as it approaches the reinforcing protrusion.

  By changing the thickness of the movable rubber film in this way, the portion where the reinforcing protrusion is formed in the movable rubber film having relatively high rigidity can be easily displaced minutely. As a result, the hydraulic pressure in the pressure receiving chamber is transmitted to the equilibrium chamber side by minute deformation of the movable rubber film, and is absorbed in the equilibrium chamber that is allowed to change in volume. Therefore, by providing the reinforcing protrusion, it is possible to effectively obtain a vibration-proofing effect based on the hydraulic pressure absorbing action due to the minute deformation of the movable rubber film while advantageously preventing the crack and advantageously ensuring the durability of the movable rubber film. .

  In the fluid-filled vibration isolator having a structure according to the present invention, it is desirable that a circular crack preventing hole penetrating the movable rubber film in the thickness direction is provided at an end of the slit.

  By forming a circular crack prevention hole at the end of the slit in this way, the stress concentration at the end of the slit can be relaxed and the generation of cracks can be advantageously suppressed. In particular, by using it together with the reinforcing protrusion, it is possible to more advantageously avoid the occurrence of cracks.

  Furthermore, in the present invention, in the fluid-filled vibration isolator having a crack prevention hole, the projected area in the axial direction of the crack prevention hole is 0 with respect to the projected area of the portion of the movable rubber film allowed to be elastically deformed. Desirably, it should be 2% or more and 1.4% or less.

  That is, if the projected area in the axial direction of the crack prevention hole is too large relative to the projected area of the movable rubber film, fluid flow occurs through the crack prevention hole even when vibration target vibration is input, and the pressure in the pressure receiving chamber is increased. Since the fluctuation is released to the equilibrium chamber side, the deterioration of the vibration proof performance tends to be a problem. On the other hand, if the projected area of the crack prevention hole is too small relative to the projected area of the movable rubber film, the stress relaxation effect at the time of opening the slit may not be obtained effectively. Therefore, by ensuring that the projected area in the axial direction of the crack prevention hole is set in the numerical range as described above with respect to the projected area of the movable rubber film, it is possible to ensure the pressure fluctuation in the pressure receiving chamber at the time of input of the vibration-proof vibration. Thus, it is possible to advantageously realize the prevention of slit cracking at the time of input of a shocking heavy load.

  The portion of the movable rubber film that is allowed to be elastically deformed is a central portion in the radial direction excluding the outer peripheral edge portion that is fixedly supported by the partition member in the movable rubber film, and is a minute portion in the thickness direction. This is a portion where deformation is allowed and a short-circuit slit and a crack prevention hole are formed in a part thereof.

  In the fluid-filled vibration isolator having a structure according to the present invention, at least a part of the slit may be curved in a plan view of the movable rubber film.

  Thus, even when at least a part of the slit is curved in a plan view of the movable rubber film, reduction or avoidance of cavitation noise as described above, and improvement in durability of the movable rubber film by preventing cracks, It can be realized effectively. In addition, even when a slit whose extension direction changes is formed, the curved rubber shape can suppress the concentration of stress and ensure the durability of the movable rubber film.

  Furthermore, in the fluid-filled vibration isolator according to the present invention having a slit having a curved portion, the slit is curved and extends, and a straight portion that linearly extends from both ends of the curved portion. It is also possible to adopt a structure having

  Even when such a structure is adopted, it is possible to achieve both prevention of cavitation noise and reduction or avoidance of cracks.

  Moreover, in the fluid-filled vibration isolator according to the present invention provided with a slit having a curved portion, the slit may be curved throughout.

  Even when a slit that is curved as a whole as described above is employed, the local concentration of stress can be prevented and the durability of the movable rubber film can be ensured.

  In the fluid-filled vibration isolator having a structure according to the present invention, the slit may be bent in a plan view of the movable rubber film.

  Even when such a bent slit is formed, it is possible to achieve both the effect of reducing abnormal noise and vibration due to cavitation and the effect of improving the durability of the movable rubber film.

  Furthermore, in the present invention, in the fluid-filled vibration isolator having such a bent portion, it is desirable that a circular stress relaxation hole is provided in the bent portion of the slit.

  Thus, by forming the circular stress relaxation hole, the stress can be relaxed and the occurrence of cracks can be advantageously prevented at the bent portion of the slit where the stress tends to concentrate during the opening operation of the slit. Thereby, even when a bent slit is formed, the durability of the movable rubber film can be advantageously ensured.

  In the fluid filled type vibration damping device according to the present invention, the slits may extend radially in three or more directions in a plan view of the movable rubber film.

  Even when slits extending radially in three or more directions are provided as described above, the effect of reducing abnormal noise and vibration by eliminating cavitation and the effect of improving the durability of the movable rubber film by preventing cracks at the slit end Can also be realized effectively. In addition, since the slits are radial, the stress acting on the ends of the slits can be kept relatively small when the slits are opened.

  Furthermore, in the present invention, in the fluid-filled vibration isolator provided with slits extending radially in three or more directions, it is desirable that the slits are formed at equal intervals in the circumferential direction.

  By adopting such slits formed at equal intervals in the circumferential direction, substantially equal stresses are dispersed and applied to the ends of the slits. Thereby, it is possible to advantageously prevent the movable rubber film from being cracked due to the concentration of stress, and to effectively improve the durability.

  Furthermore, in the present invention, in the fluid-filled vibration isolator provided with slits extending radially in three or more directions at equal intervals in the circumferential direction, the slits extend radially in four directions. It is desirable that they are formed at equal intervals.

  Even when such a slit is employed, it is possible to effectively prevent abnormal noise and vibration due to cavitation, and to effectively prevent the occurrence of cracks at the end of the slit. In particular, by forming the slits so as to extend radially in four directions, it is possible to effectively realize the closed state of the slits when inputting vibration-proof target vibrations and the opening operation of the slits when shocking vibrations are input.

  Further, in the fluid filled type vibration damping device according to the present invention, the slits are formed at a plurality of locations with respect to the movable rubber film, and the reinforcing protrusions are provided outside the slits, respectively. May be.

  Even with such a structure, cracks at the end of each slit can be effectively prevented at each reinforcing projection, and cavitation noise can be reduced or avoided, and the durability of the movable rubber film due to the occurrence of cracks Prevention of the reduction can be effectively realized.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 shows an engine mount 10 for an automobile as a first embodiment of a fluid filled type vibration damping device according to the present invention. The engine mount 10 includes a first mounting member 12 as a first mounting member that is attached to one member that is vibration-proof connected, and a second mounting member that is attached to the other member that is vibration-proof connected. The second mounting bracket 14 has a structure in which the main rubber elastic body 16 is elastically connected to each other. And, for example, the first mounting bracket 12 is attached to the power unit of the automobile which is one member to be vibration-proof connected, and the second mounting bracket 14 is attached to the body of the automobile which is the other member to be vibration-proof connected. As a result, the power unit is supported by the vehicle body in a vibration-proof manner. In the following description, the vertical direction refers to the vertical direction in FIG. 1, which is the main vibration input direction.

  More specifically, the first mounting bracket 12 is a highly rigid member formed of a metal material such as iron or aluminum alloy, and has a substantially circular block shape. Further, a flange portion 18 that extends radially outward is integrally formed at the upper end portion of the first mounting member 12. Further, a bolt hole 20 is formed so as to open on the upper end surface of the first mounting member 12 and extend on the central axis, and an internal thread is engraved on the inner peripheral surface of the bolt hole 20. The first mounting bracket 12 is bolted to a power unit (not shown) by, for example, a mounting bolt (not shown) screwed into the bolt hole 20.

  On the other hand, the second mounting bracket 14 is a highly rigid member formed of the same metal material as that of the first mounting bracket 12 and has a thin cylindrical shape with a large diameter as a whole. In addition, a constricted portion 22 is provided at an intermediate portion in the axial direction of the second mounting bracket 14. The constricted portion 22 includes a tapered portion 24 that gradually decreases in diameter toward the lower side in the axial direction, and an annular stepped portion 26 that widens from the lower end portion of the tapered portion 24 toward the outer peripheral side. An annular step 28 that extends toward the outer periphery is formed at the lower end of the second mounting bracket 14, and a large-diameter cylindrical caulking that extends downward on the outer peripheral edge of the step 28. The piece 29 is integrally formed. Such a second mounting bracket 14 is fixed to the vehicle body, for example, by attaching a bracket (not shown) fitted and fixed to the second mounting bracket 14 to the vehicle body.

  The first mounting bracket 12 and the second mounting bracket 14 are disposed on the same central axis, and the first mounting bracket 12 is spaced apart from the second mounting bracket 14 in the axial direction. Be placed. The main rubber elastic body 16 is interposed between the first mounting metal 12 and the second mounting metal 14, so that the first mounting metal 12 and the second mounting metal 14 are connected to the main rubber elastic body. 16 is elastically connected.

  The main rubber elastic body 16 is formed of a rubber elastic body having a thick, substantially truncated cone shape. A large-diameter circular recess 30 is formed in the central portion of the main rubber elastic body 16 in the radial direction so as to open to the large-diameter side end surface (the lower end surface in FIG. 1). The first mounting bracket 12 is inserted into the end portion of the main rubber elastic body 16 on the small diameter side, and the lower surface of the flange portion 18 is superimposed on the axial end surface of the main rubber elastic body 16 on the small diameter side. In this way, it is vulcanized and bonded. On the other hand, on the outer peripheral surface of the large-diameter side end portion of the main rubber elastic body 16, the upper portion of the second mounting bracket 14 and the tapered portion 24 are overlapped and vulcanized and bonded. Thereby, the first mounting bracket 12 and the second mounting bracket 14 are connected to each other by the main rubber elastic body 16. In addition, the main rubber elastic body 16 in the present embodiment is formed as an integrally vulcanized molded product that integrally includes the first mounting bracket 12 and the second mounting bracket 14.

  Further, a seal rubber layer 32 integrally formed with the main rubber elastic body 16 is fixed to the inner peripheral surface of the second mounting bracket 14. The seal rubber layer 32 is formed of a thin rubber film, and is formed so as to cover a portion from the inner peripheral surface of the step portion 26 to the inner peripheral portion of the step 28 in the second mounting bracket 14.

  In addition, a diaphragm 34 as a flexible film is disposed at the lower end opening of the second mounting bracket 14. The diaphragm 34 is formed of a rubber film having a thin, large-diameter, generally circular dome shape, so that elastic deformation is easily allowed. A fixing metal fitting 36 is fixed to the outer peripheral edge of the diaphragm 34. The fixing bracket 36 has a substantially annular shape, and integrally includes a cylindrical fixing portion 38 and a caulking portion 40 that spreads from the upper end of the fixing portion 38 toward the outer peripheral side. Then, the outer peripheral edge of the diaphragm 34 is vulcanized and bonded to the fixing portion 38 of the fixing bracket 36, whereby the diaphragm 34 is formed as an integrally vulcanized molded product integrally provided with the fixing bracket 36. In the present embodiment, the fixing bracket 36 is covered with a rubber layer integrally formed with the diaphragm 34 over substantially the entire surface excluding the outer peripheral edge portion and the upper end surface of the caulking portion 40.

  Such a diaphragm 34 is assembled to the second mounting bracket 14. That is, the outer peripheral edge portion of the caulking portion 40 of the fixing bracket 36 is overlapped from below with respect to the step 28 provided at the lower end portion of the second mounting bracket 14, and the caulking portion 40 is overlapped with the second mounting bracket 14. The diaphragm 34 is fixed to the lower end portion of the second mounting bracket 14 by being caulked and fixed by a caulking piece 29 formed integrally with the second mounting bracket 14.

  As described above, the diaphragm 34 is assembled to the integrally vulcanized molded product of the main rubber elastic body 16 including the first mounting bracket 12 and the second mounting bracket 14, so that the shaft of the second mounting bracket 14 can be obtained. The opening on the upper side in the direction is closed fluid-tightly by the main rubber elastic body 16, and the opening on the lower side in the axial direction of the second mounting bracket 14 is closed fluid-tightly by the diaphragm 34. Thus, a fluid sealing region 42 as a fluid chamber sealed from the outside is formed between the main rubber elastic body 16 and the diaphragm 34 on the inner peripheral side of the second mounting bracket 14.

  Further, in the fluid sealing region 42, an incompressible fluid such as water, alkylene glycol, polyalkylene glycol, silicone oil, or a mixture thereof is sealed as a sealing fluid. The sealed fluid is not particularly limited, but the viscosity is 0.1 Pa · s or less in order to advantageously obtain a vibration isolation effect based on the resonance action of the fluid flowing through the orifice passage 82 described later. It is desirable to employ a low viscosity fluid. In addition, the fluid is sealed in such a manner that the diaphragm 34 is assembled to the second mounting bracket 14 (an integrally vulcanized molded product of the main rubber elastic body 16 including the second mounting bracket 14). It can be realized advantageously by performing in.

  A partition member 44 is accommodated in the fluid sealing area 42. The partition member 44 has a thick, substantially disk shape, and includes a partition metal body 46 and a lid metal 48 in the present embodiment.

  The partition metal fitting body 46 as a whole has a thick, substantially disk shape, and its outer peripheral edge projects downward. In addition, a circumferential groove 52 is formed in a radially intermediate portion of the partition fitting body 46. The circumferential groove 52 is a concave groove that opens on the upper surface of the partition metal body 46 and is formed to extend in the circumferential direction by a predetermined length.

  In addition, a circular central recess 54 that opens upward is formed in the central portion in the radial direction of the partition metal fitting 46, and a central hole 56 that passes through the center of the bottom wall portion of the central recess 54. Is formed. The central hole 56 has a certain circular cross section, and is formed so as to penetrate the radial center portion of the partition metal fitting body 46 in the axial direction. Further, a central protrusion 58 is integrally formed with the partition metal body 46 at the opening peripheral edge of the central hole 56. The central protrusion 58 has an annular shape extending in the circumferential direction, and protrudes upward from the inner peripheral edge of the bottom wall portion of the central recess 54. In addition, by providing the central ridge 58 on the inner peripheral edge of the partition metal fitting body 46, it extends over the entire circumference in the circumferential direction by the cooperation of the central ridge 58 and the wall of the central recess 54. A concave groove is provided that opens toward the front.

  On the other hand, the lid metal fitting 48 is a thin-walled large-diameter plate, and in this embodiment, has a stepped disk shape in which the central portion is positioned above the outer peripheral portion. Further, a through hole 60 is formed in the central portion of the lid metal 48 in the radial direction. The through hole 60 is a circular hole formed with a diameter substantially equal to the central hole 56 of the partition metal fitting 46, and is formed so as to penetrate the radial center portion of the lid metal 48 in the plate thickness direction. A support protrusion 62 is integrally formed on the opening peripheral edge of the through hole 60. The support protrusion 62 has an annular shape extending over the entire circumference, and is formed so as to protrude downward from the inner peripheral edge of the lid fitting 48.

  The lid metal 48 is overlapped and combined with the upper end surface of the partition metal body 46 from above. As a result, the upper opening of the circumferential groove 52 formed so as to open to the upper end surface of the partition metal body 46 is covered with the lid metal 48 to form a tunnel-like flow path extending in a predetermined length in the circumferential direction. Has been.

  A movable rubber film 64 is disposed between the partition metal body 46 and the cover metal 48. The movable rubber film 64 is formed of a substantially disc-shaped rubber elastic body as shown in FIGS. 2 and 3, and in this embodiment, the central portion of the movable rubber film 64 has a substantially constant thickness. And the outer peripheral portion gradually becomes thicker toward the outer peripheral side. Further, annular support portions 66 projecting to both sides in the thickness direction are integrally formed on the outer peripheral edge portion of the movable rubber film 64, and the corners are curved and rounded in a substantially rectangular cross-sectional shape on the entire circumference. It is provided continuously over. In addition, the annular support part 66 in the present embodiment extends a substantially constant cross-sectional shape over the entire circumference.

  Further, a short-circuit slit 72 as a slit is formed in the central portion of the movable rubber film 64 in the radial direction. The short-circuit slit 72 extends substantially radially from the radial center of the movable rubber film 64 in a plan view of the movable rubber film 64, and is configured by a notch that penetrates the movable rubber film 64 in the thickness direction. The short-circuit slit 72 is formed by four cuts extending linearly.

  In the present embodiment, four cuts are formed at equal intervals in the circumferential direction, and adjacent cuts in the circumferential direction are perpendicular to each other. As a result, as shown in FIG. 2, a cross-shaped short-circuit slit 72 is formed in the movable rubber film 64 when viewed in the mount axis direction.

  The central portion of the movable rubber film 64 in the present embodiment is in a state of being divided into four at equal intervals in the circumferential direction by the short-circuit slit 72. Here, in the stationary state, the central portion of the movable rubber film 64 divided into four at equal intervals in the circumferential direction by the short-circuit slit 72 is maintained in a state of spreading in the direction perpendicular to the axis, and the short-circuit slit 72 is movable rubber. The membrane 64 is closed based on the elasticity of the membrane 64.

  In the present embodiment, a crack prevention hole 74 is formed at the end of the short-circuit slit 72. As shown in FIGS. 2 and 3, the crack prevention hole 74 is a small-diameter circular hole having a substantially constant cross-sectional shape and linearly extending in the mount axis direction, and penetrates the movable rubber film 64 in the thickness direction. Is formed. Moreover, the crack prevention hole 74 is provided in the outer side edge part of the short-circuit slit 72, and in this embodiment, the four crack prevention holes 74 are formed at equal intervals in the circumferential direction. Note that the end portion of the short-circuit slit 72 referred to here is an end portion of the four cuts constituting the short-circuit slit 72 and an end portion on the radially outer side not connected to other cuts.

  Note that the projected area in the axial direction of the crack prevention hole 74 (the area of the crack prevention hole 74 in FIG. 2) is a deformation allowable portion that is a portion located on the inner peripheral side of the annular support portion 66 of the movable rubber film 64. The projected area in the direction of the mount axis (the area of the portion in FIG. 2) is desirably 0.2% or more and 1.4% or less, and more preferably 0.4% or more and 1.2% or less. When the lid is opened and the crack prevention hole 74 is too large with respect to the size of the movable rubber film 64, the fluid flow through the crack prevention hole 74 is generated even when a vibration isolation target vibration described later is input. There is a possibility that the fluid flow through 82 is not effectively caused and the intended vibration-proof performance cannot be realized. On the other hand, if the crack prevention hole 74 is too small, the stress concentration mitigating action at the end of the short-circuit slit 72 may not be sufficiently exhibited.

  Here, reinforcing ribs 76 as reinforcing protrusions are provided outside the crack prevention holes 74 that are the ends of the short-circuit slits 72 formed in the movable rubber film 64. The reinforcing rib 76 is a protrusion of a rubber elastic body integrally formed with the movable rubber film 64 at the radial intermediate portion of the movable rubber film 64 and protrudes toward both sides in the thickness direction of the movable rubber film 64. Yes. In the present embodiment, the reinforcing ribs 76 are projected at equal heights toward both sides in the thickness direction of the movable rubber film 64. In the present embodiment, the base end portion of the reinforcing rib 76 rises in the axial direction substantially orthogonal to the movable rubber film 64 spreading in the direction perpendicular to the axis. Further, the reinforcing ribs 76 in the present embodiment extend in the circumferential direction with a substantially constant semicircular cross section, and gradually become narrower toward the protruding tip side.

  In addition, the reinforcing ribs 76 in the present embodiment are continuously formed in the circumferential direction and have a substantially annular shape as a whole. Due to the annular reinforcing rib 76, the movable rubber film 64 is partially thick at the radial intermediate portion.

  The annular reinforcing rib 76 is formed so as to surround the outer periphery of the short-circuit slit 72 over the entire circumference, and the short-circuit slit 72 extending radially in the radial direction from the radial center of the movable rubber film 64. Reinforcing ribs 76 are provided orthogonal to the extension lines. In the present embodiment, as shown in FIGS. 2 and 3, the end of the short-circuit slit 72 is formed to have a length that extends to the inner peripheral surface of the base end of the reinforcing rib 76. The rib 76 is formed so that the end of the short-circuit slit 72 is in contact with the rib 76.

  Further, in the present embodiment, as shown in FIG. 3, the central portion of the movable rubber film 64 surrounded by the reinforcing rib 76 is formed with a substantially constant thickness, and the reinforcement in the movable rubber film 64 is performed. As the portion located on the outer peripheral side of the rib 76 approaches the reinforcing rib 76, in other words, gradually becomes thinner toward the inner peripheral side. A short-circuit slit 72 and a crack prevention hole 74 are formed in the central portion of the movable rubber film 64 having a substantially constant thickness (the inner peripheral side portion of the reinforcing rib 76 in the movable rubber film 64). The reinforcing rib 76 and the annular support 66 are connected to each other in the radial direction by the outer peripheral portion of the movable rubber film 64 whose thickness is changed in the radial direction.

  The reinforcing rib 76 preferably has a predetermined width and height (distance from the downward projecting tip to the upward projecting tip). That is, in the present embodiment in which the diameter of the movable rubber film 64 is 25 mm, the width of the reinforcing rib 76 is preferably 1 mm to 4 mm, and the height of the reinforcing rib 76 is 3 mm to 8 mm. desirable. More preferably, the width of the reinforcing rib 76 is 3 mm and the height is 6 mm. When the lid and the reinforcing rib 76 are too wide or too wide, the movable rubber film 64 is too rigid and adversely affects the opening / closing operation of the short-circuit slit 72. This is because the crack prevention effect described later may not be sufficiently obtained.

  The movable rubber film 64 according to this embodiment is sandwiched between the partition metal body 46 and the lid metal 48 and assembled to the metal fittings 46 and 48. That is, the movable rubber film 64 is fitted in the central recess 54 formed in the central portion of the partition metal body 46, and the annular support portion 66 provided on the outer peripheral edge of the movable rubber film 64 is the central recess 54. The annular support portion 66 is sandwiched between the partition metal body 46 and the lid metal 48 that is superimposed on the partition metal body 46 from above while being positioned and supported between the peripheral wall portion and the radial direction of the central protrusion 58. Accordingly, the movable rubber film 64 is attached in a state where the outer peripheral portion is fixedly supported with respect to the partition metal body 46 and the lid metal 48.

  When the movable rubber film 64 is assembled to the partition metal body 46 and the lid metal 48, the outer peripheral edge of the movable rubber film 64 is fixedly supported by the partition metal body 46 and the lid metal 48 and is movable. A central portion in the radial direction of the rubber film 64 is positioned so as to cover a central hole 56 formed in the partition metal fitting body 46 and a through hole 60 formed in the lid metal fitting 48. As a result, the movable rubber film 64 can be elastically deformed in the axial direction through the central hole 56 and the through hole 60 in the central portion in the radial direction while the outer peripheral edge portion is fixed. In this way, the central hole 56 and the through hole 60 are blocked by the movable rubber film 64, whereby the partition member 44 according to the present embodiment including the movable rubber film 64 is configured. In the present embodiment, the annular support portion 66 formed on the outer peripheral edge of the movable rubber film 64 is constrained by the partition member 44, and the movable rubber film 64 in which the short-circuit slit 72 and the crack prevention hole 74 are formed. The central portion of the center is positioned on the extension of the central hole 56 and the through hole 60, and deformation in the axial direction is allowed.

  Further, the crack prevention hole 74 formed in the movable rubber film 64 is always in a communication state when the movable rubber film 64 is attached to the partition member 44.

  The partition member 44 having such a structure is supported by the second mounting bracket 14 and accommodated in the fluid sealing region 42. That is, before the diaphragm 34 is assembled to the second mounting bracket 14, the partition member 44 is inserted into the second mounting bracket 14 from the lower opening and provided to the second mounting bracket 14. The stepped portion 26 is brought into contact with the stepped portion 26 through the seal rubber layer 32 from below. Then, the partition member 44 is fitted and fixed to the second mounting member 14 and supported by subjecting the second mounting member 14 to diameter reduction processing such as eight-way drawing.

  In the present embodiment, the diaphragm 34 is assembled to the second mounting bracket 14 in a state where the partition member 44 is assembled to the second mounting bracket 14. The upper surface of the inner peripheral edge portion of the caulking portion 40 is brought into contact with the lower surface of the outer peripheral edge portion of the partition metal fitting body 46, so that the diaphragm 34 and the partition member 44 are relatively aligned, and the partition member 44 is stepped. 26 and the fixture 35 are sandwiched between the axial directions to be positioned.

  Further, the partition member 44 is supported by the second mounting bracket 14 via the seal rubber layer 32, so that the partition member 44 and the second mounting bracket 14 are sealed in a fluid-tight manner. Is assembled to the second mounting bracket 14. Thus, in the assembled state in which the partition member 44 is accommodated and disposed in the fluid sealing region 42, the fluid sealing region 42 is divided into two sides sandwiching the partition member 44. Further, a pressure receiving chamber 78 in which a part of the wall portion is constituted by the main rubber elastic body 16 and is subjected to pressure fluctuation when vibration is input is formed on one side (upper in FIG. 1) sandwiching the partition member 44. In addition, on the other side (lower side in FIG. 1) across the partition member 44, a part of the wall portion is configured by the diaphragm 34, and an equilibrium chamber 80 in which volume change is easily allowed is formed. ing. Both chambers 78 and 80 are filled with incompressible fluid sealed in the fluid sealing region 42, respectively.

  Further, the tunnel-like flow path formed by covering the opening of the circumferential groove 52 with the lid fitting 48 is communicated with the pressure receiving chamber 78 through a communication hole (not shown) formed at one end of the lid fitting 48. At the same time, the other end is communicated with the equilibrium chamber 80 through a communication hole (not shown) formed in the partition metal fitting body 46. Thus, an orifice passage 82 that communicates the pressure receiving chamber 78 and the equilibrium chamber 80 with each other is formed by using the circumferential groove 52 formed in the partition member 44.

  In addition, the orifice passage 82 in the present embodiment is tuned so that the resonance frequency of the fluid flowing inside is a low frequency of about 10 Hz, and with respect to low frequency vibration corresponding to an engine shake of an automobile, etc. An anti-vibration effect based on a flow action such as a resonance action of the fluid flowing through the orifice passage 82 is effectively exhibited. Such tuning of the orifice passage 82 can be set by appropriately adjusting the ratio of the passage length and the passage sectional area of the orifice passage 82.

  Further, in a state where the partition member 44 is assembled to the second mounting member 14, a through hole 60 formed in the lid member 48 is formed on one surface in the central portion in the radial direction of the movable rubber film 64. The pressure in the pressure receiving chamber 78 is exerted. On the other hand, the pressure in the equilibrium chamber 80 is applied to the other surface of the movable rubber film 64 in the central portion in the radial direction through the central hole 56 formed in the partition metal fitting body 46. As a result, the movable rubber film 64 is elastically deformed based on the relative pressure difference between the pressure receiving chamber 78 and the equilibrium chamber 80, and the pressure exerted on the pressure receiving chamber 78 when medium to high frequency small amplitude vibration is input. The movable rubber film 64 constitutes a hydraulic pressure absorption mechanism that absorbs the fluctuations by escaping to the equilibrium chamber 80 side.

  Note that, in the non-input state of vibration, the central portion of the movable rubber film 64 in which the short-circuit slit 72 is formed extends in the direction perpendicular to the axis, and the short-circuit slit 72 formed in the movable rubber film 64 is blocked. Held in a state. The crack prevention hole 74 is always open at both ends toward the pressure receiving chamber 78 and the equilibrium chamber 80. By appropriately adjusting the diameter and length of the crack prevention hole 74, the flow of fluid is prevented from vibration. The crack prevention hole 74 is substantially closed, so that the performance is not affected.

  In the automobile engine mount 10 having the structure according to this embodiment, the first mounting bracket 12 is mounted on a power unit (not shown) and the second mounting bracket 14 is mounted on a vehicle body (not shown). When a vibration load is input between the first mounting bracket 12 and the second mounting bracket 14 in the vertical direction, which is the main vibration input direction, the intended vibration-proofing effect is based on the fluid flow action and the like. It has come to be demonstrated.

  That is, when a low frequency large amplitude vibration such as an engine shake is input between the first mounting bracket 12 and the second mounting bracket 14 while the automobile is running, the main rubber elastic body 16 is elastically deformed. A pressure fluctuation is exerted in the pressure receiving chamber 78. Accordingly, the sealed fluid is caused to flow between the pressure receiving chamber 78 and the equilibrium chamber 80 through the orifice passage 82 tuned to a low frequency range corresponding to an engine shake or the like, and based on a fluid action such as a resonance action of the fluid. Anti-vibration effects such as a high damping effect are effectively exhibited. Note that when the vibration is input in the low frequency range, the amplitude of the input vibration is large, so that the hydraulic pressure absorption effect due to the minute elastic deformation of the movable rubber film 64 is not exhibited effectively. Therefore, a sufficient internal pressure fluctuation is exerted on the pressure receiving chamber 78, and fluid flow through the orifice passage 82 can be advantageously generated.

  On the other hand, when medium to high frequency small amplitude vibration such as idling vibration is input between the first mounting bracket 12 and the second mounting bracket 14 when the automobile is stopped, the pressure receiving chamber 78 and the equilibrium chamber 80 A relative pressure difference is generated between them, and the movable rubber film 64 is slightly deformed based on the pressure difference. Then, the hydraulic pressure in the pressure receiving chamber 78 is transmitted to the equilibrium chamber 80 side by the minute deformation of the movable rubber film 64. As a result, an anti-vibration effect such as a low dynamic spring effect based on the hydraulic pressure absorbing action due to minute elastic deformation of the movable rubber film 64 is effectively exhibited.

  In this embodiment, when the movable rubber film 64 is deformed by inputting a normal vibration load to be subjected to vibration isolation, the short-circuit slit 72 formed in the movable rubber film 64 is kept closed. It has come to be. Such a closed state is realized by the bending elasticity of the movable rubber film 64. By appropriately setting the rubber material, the size, the shape, and the like of the movable rubber film 64, an external force exerted by the input of the vibration-proof target vibration is applied. Accordingly, the short-circuit slit 72 is held in a cut-off state.

  In the present embodiment, the outer peripheral portion of the movable rubber film 64 is gradually thinner than the reinforcing rib 76 inward in the radial direction, and the portion connected to the reinforcing rib 76 is sufficiently thin. . As a result, the central portion in the radial direction of the movable rubber film 64, which tends to have relatively high rigidity due to the formation of the reinforcing rib 76, can be easily displaced minutely.

  Furthermore, an impact vibration load is input between the first mounting bracket 12 and the second mounting bracket 14 due to, for example, overcoming a step during driving of the automobile, and the pressure in the pressure receiving chamber 78 is greatly reduced. As a result, the short-circuit slit 72 formed in the movable rubber film 64 is opened. That is, when the pressure receiving chamber 78 is greatly depressurized, the negative pressure in the pressure receiving chamber 78 is exerted on the movable rubber film 64, and the suction force toward the pressure receiving chamber 78 acts on the movable rubber film 64. With this suction force, the movable rubber film 64 is sucked toward the pressure receiving chamber 78 side and elastically deformed toward the pressure receiving chamber 78 side.

  As a result, the short-circuit slit 72 is opened against the elasticity of the movable rubber film 64, and the pressure receiving chamber 78 and the equilibrium chamber 80 are communicated with each other through the short-circuit slit 72. Then, a fluid flow through the short-circuit slit 72 is generated between the pressure receiving chamber 78 and the equilibrium chamber 80, and the negative pressure in the pressure receiving chamber 78 is eliminated as quickly as possible. Therefore, it is possible to effectively prevent the generation of abnormal noise and vibration that are considered to be caused by the pressure drop in the pressure receiving chamber 78.

  As is apparent from the above description, the shut-off state and the communication state of the short-circuit slit 72 are switched according to the pressure acting on the pressure receiving chamber 78, and the elasticity of the movable rubber film 64 is utilized. The valve mechanism in the present embodiment is configured. In the present embodiment, four short-circuit slits 72 extending radially from the center in the radial direction of the movable rubber film 64 are formed, and the cut-off state is established with the pressure in the pressure receiving chamber 78 set in advance as a boundary. Switching of the communication state is realized with high accuracy.

  Here, in the movable rubber film 64 having a structure according to the present embodiment, a reinforcing rib 76 is provided outside the short-circuit slit 72. The reinforcing rib 76 protrudes in the axial direction substantially perpendicular to the movable rubber film 64, and is formed at a position close to the end of the short-circuit slit 72. In this way, the reinforcing rib 76 is formed, and the thickness of the movable rubber film 64 is suddenly increased outside the end of the short-circuit slit 72. It is possible to advantageously stop the crack of the movable rubber film 64 generated at the end of 72 from extending in the extension line direction of the short-circuit slit 72 at the location where the reinforcing rib 76 is formed. As a result, the durability of the movable rubber film 64 can be improved, and the opening allowable region of the short-circuit slit 72 can be stably maintained in the initial state, thereby reducing the target cavitation noise. It is possible to effectively achieve both vibration isolation performance.

  In addition, the end of the short-circuit slit 72 in which the crack prevention hole 74 is formed is formed close to the inner edge of the reinforcing rib 76. Thereby, not only the progress of cracks but also the occurrence of cracks at the end of the short-circuit slit 72 can be effectively prevented. Therefore, both of the target cavitation noise reduction effect and vibration isolation performance can be advantageously realized.

  Further, in the present embodiment, the annular reinforcing rib 76 that extends continuously over the entire circumference is formed, and it is possible to advantageously prevent the crack from extending by avoiding the reinforcing rib 76. Therefore, it is possible to stably and advantageously realize the durability improvement of the movable rubber film 64 and the intended vibration isolation performance and quietness.

  In the present embodiment, a circular crack prevention hole 74 is formed at the end of the short-circuit slit 72 on the inner peripheral side of the reinforcing rib 76. This crack prevention hole 74 relieves stress concentration on the end of the short-circuit slit 72 when the movable rubber film 64 is elastically deformed, and it is more advantageous that a crack occurs in the end of the short-circuit slit 72 in the movable rubber film 64. Can be prevented. In addition, when the crack prevention hole has a cross-sectional shape having a corner portion such as a rectangle, the concentration of stress at the corner portion tends to be a problem, but in this embodiment, the crack prevention hole 74 is a circular hole. Thus, the stress concentration is advantageously alleviated.

  In particular, in this embodiment, the crack prevention hole 74 is set to have a predetermined size with respect to the size of the movable rubber film 64. Accordingly, while effectively realizing the stress relaxation action, the fluid flow through the crack prevention hole 74 at the time of normal vibration input is prevented, and the progress of the crack of the movable rubber film 64 is prevented and the intended vibration isolation is achieved. The effect can be realized effectively.

Table 1 shows measurement results obtained by actually measuring the influence of the change in the length of the short-circuit slit 72 on the vibration isolation performance and the noise reduction effect. That is, the reduction rate of the vibration isolation performance and the abnormal sound level when the engine mount 10 having the structure according to the first embodiment is vibrated with an amplitude of ± 2 mm and ± 4 mm are shown.

  According to this, first, it can be seen that the anti-vibration performance greatly changes in accordance with the change in the length of the short-circuit slit 72. That is, as the short-circuit slit 72 becomes larger, the vibration proof performance is remarkably lowered. For this reason, when the end of the short-circuit slit 72 is cracked, the substantial length of the short-circuit slit 72 is increased, and the opening of the short-circuit slit 72 is increased, it is difficult to achieve the desired vibration isolation performance. It became clear that.

  Next, it became clear that the change in the abnormal sound level was relatively small with respect to the change in the length of the short-circuit slit 72. That is, as is apparent from the measurement results when the length of the short-circuit slit 72 is 3.5 mm and 5 mm when excited with an amplitude of ± 4 mm, if the short-circuit slit 72 is too short, the short-circuit slit 72 is Since it cannot open sufficiently and the reduction of the negative pressure in the pressure receiving chamber 78 due to a short circuit is not sufficiently realized, the abnormal noise level becomes high. However, in the short-circuit slit 72 having a sufficient length (5 mm when ± 4 mm is vibrated) and the short-circuit slit 72 having a length longer than that (7 mm, 10 mm, and 15 mm when ± 4 mm is vibrated), the noise level changes. Is moderate, and an equivalent noise reduction effect is exhibited.

  Accordingly, even when the length of the short-circuit slit 72 is increased more than necessary, the noise reduction effect is hardly changed, and the short-circuit slit 72 having the shortest possible length within the range in which an effective noise reduction effect can be obtained. It has been clarified by actual measurement that, by forming, it is possible to effectively achieve both the desired anti-vibration performance and the noise reduction effect. In other words, the fact that the substantial length of the short-circuit slit 72 is increased due to a crack at the end of the short-circuit slit 72 is not effective in terms of reducing abnormal noise, and the desired vibration-proof performance is achieved. It was confirmed by actual measurement that it was extremely inconvenient from the viewpoint of realization.

  From these, the present embodiment in which cracks generated at the end of the short-circuit slit 72 formed in the movable rubber film 64 can be effectively prevented and the substantial length of the short-circuit slit 72 can be maintained in the initial state. The engine mount 10 according to the embodiment has an excellent effect in order to achieve both a reduction effect of cavitation noise and an anti-vibration effect, and can achieve both high quietness and shock-absorbing performance in the vehicle interior. It becomes possible.

  Next, FIGS. 4 and 5 show a movable rubber film 84 constituting an automobile engine mount as a second embodiment of the fluid filled type vibration damping device having a structure according to the present invention. In addition, in the following description, about the member thru | or site | part substantially the same as said 1st embodiment, description is abbreviate | omitted by attaching | subjecting the same code | symbol in a figure.

  That is, the movable rubber film 84 shown in FIGS. 4 and 5 does not have the crack prevention hole 74 formed at the end of the short-circuit slit 72 in the first embodiment, The end portion is directly brought close to the reinforcing rib 76. The movable rubber film 84 according to this embodiment shown in FIGS. 4 and 5 is assembled to the partition member 44 constituting the automobile engine mount, similarly to the movable rubber film 64 in the first embodiment.

  Thus, the circular crack prevention hole 74 does not necessarily have to be formed at the end of the short-circuit slit 72, and even in that case, the short-circuit slit is formed by the reinforcing rib 76 formed outside the short-circuit slit 72. The occurrence of cracks at the end of 72 can be effectively prevented.

  FIG. 6 shows a movable rubber film 86 that is employed in an automotive engine mount that is a third embodiment of the present invention. In the movable rubber film 86, on the inner peripheral side of the annular reinforcing rib 76, a short-circuit slit 88 constituted by three cuts linearly extending and radially arranged is formed. In particular, in the present embodiment, the short-circuit slits 88 have a radial shape extending at equal intervals in the circumferential direction, and the cuts have the same length.

  In this way, the short-circuit slit does not necessarily have to be formed by four cuts extending orthogonally to each other, but by the short-circuit slit 88 formed by three cuts as shown in the present embodiment. However, by adjusting the notch length and the like appropriately, it is possible to achieve both an effective anti-cavitation effect and the desired vibration-proof performance. Needless to say, a short-circuit slit may be formed by five or more cuts.

  7 and 8 show a movable rubber film 90 constituting an automobile engine mount as a fourth embodiment of the fluid filled type vibration damping device according to the present invention. That is, the movable rubber film 90 in the present embodiment is formed with a plurality of reinforcing ribs 92 that are mutually independent in the circumferential direction.

  More specifically, the reinforcing rib 92 has a substantially constant oval cross section and extends in a predetermined length in the circumferential direction, and protrudes toward both sides in the thickness direction at a radially intermediate portion of the movable rubber film 90. Yes. In addition, one reinforcing rib 92 is formed outside each end of the short-circuit slit 72. In the present embodiment, four reinforcing ribs 92 are formed at equal intervals in the circumferential direction.

  Even when a plurality of reinforcing ribs 92 that are independent in the length direction are provided as described above, the end of the short-circuit slit 72 is brought close to the reinforcing rib 92, so that a crack is generated at the end of the short-circuit slit 72. And can effectively prevent elongation. Moreover, by forming the reinforcing rib 92 into a shape that is divided in the circumferential direction, it is possible to reduce the film rigidity of the movable rubber film 90 at the location where the reinforcing rib 92 is formed and the inner peripheral side thereof, and input vibration during idling. At this time, the hydraulic pressure absorbing action by the minute deformation of the movable rubber film 90 can be exhibited advantageously.

  Further, FIG. 9 shows a movable rubber film 94 constituting an automobile engine mount as a fifth embodiment of the fluid filled type vibration damping device according to the present invention. In the movable rubber film 94 having the structure according to the present embodiment, the short-circuit slit 96 is configured by two cuts connected in series with each other. That is, as shown in FIG. 9, two linearly extending cuts are connected to each other at one end portion, and as a whole, substantially in plan view of the movable rubber film 94. A short-circuit slit 96 that is bent and extends in a V shape is formed. In addition, a crack prevention hole 74 is formed at each end of the short-circuit slit 96, and a circular stress relaxation hole 98 is formed in a refracting portion (folded portion) of the short-circuit slit 96. In the present embodiment, the crack prevention hole 74 and the stress relaxation hole 98 are circular holes having the same shape. The crack prevention hole 74 and the stress relaxation hole 98 do not necessarily have the same shape. For example, the cross-sectional sizes may be different.

  In this way, the short-circuit slits may not be formed radially, for example, a plurality of linear or curved cuts may be connected in series, and may be bent and extended as a whole. good. In addition, when the short-circuit slit 96 that bends in this way is adopted, the stress concentration hole 98 is formed in the connecting portion (folded portion) that becomes the bending point (folded point), thereby reducing the stress concentration at the folded portion. Thus, it is possible to prevent the occurrence and elongation of cracks at the location.

  FIG. 10 shows a movable rubber film 100 according to the sixth embodiment of the present invention. The movable rubber film 100 has a shape in which one end of each of the cuts extending linearly at an angle with each other is connected to each other by a cut extending in a curved manner, in other words, a curved shape. A short-circuit slit 102 having a shape in which a linear cut extends from both ends of the cut is formed.

  Further, FIG. 11 shows a movable rubber film 104 according to the seventh embodiment of the present invention. The movable rubber film 104 is formed with a short-circuit slit 106 that is curved in a circular arc shape at the central portion in the radial direction.

  As is clear from the movable rubber films 100 and 104 shown in FIGS. 10 and 11, a part or all of the short-circuit slit may extend in a curved shape in a plan view of the movable rubber film. By adopting such a short-circuit slit having a curved portion, stress concentration in the bent portion of the slit is reduced as compared with the bent short-circuit slit 96, and the occurrence and extension of cracks can be reduced. .

  As mentioned above, although one Embodiment of this invention has been described, this is an illustration to the last, Comprising: This invention is not limited at all by the specific description in this Embodiment.

  For example, like the movable rubber film 108 shown in FIG. 12, three or more (four are illustrated in FIG. 12) linear cuts are connected in series and extended in a bent shape as a whole. It is also possible to employ the short-circuit slit 110. In such a case, by forming the stress relaxation holes 98 in the bent portions of the short-circuit slit 110, the stress concentration in the bent portions can be relaxed and the occurrence of cracks can be prevented.

  Further, the short-circuit slit is not necessarily formed at one place of the movable rubber film, and may be formed at two or more places independently of each other. In this case, each short-circuit provided independently Reinforcing ribs are formed on the outer sides of the ends of the slits. Further, in order to stabilize the opening / closing operation of the short-circuit slit, it is desirable that the short-circuit slit is formed in the central portion in the radial direction of the movable rubber film, but it is formed at a position separated from the central portion in the radial direction by a predetermined distance. Also good. Specifically, for example, in the movable rubber film 112 shown in FIG. 13, four short-circuit slits 72 having four straight lines extending radially are formed in the radial intermediate portion of the movable rubber film 112. Each short-circuit slit 72 is surrounded by an annular reinforcing rib 76 on the outside. Also in the movable rubber film 112 having such a structure, the length of the short-circuit slit 72, the thickness of the movable rubber film 112 in the portion where the short-circuit slit 72 is formed, and the like are adjusted, and the opening allowance and communication state of the short-circuit slit 72 are blocked. By appropriately setting the set pressure and the like that can be switched to the state, it is possible to achieve both the desired effect of eliminating abnormal noise and the anti-vibration performance.

  In addition, the cross-sectional shape of the reinforcing rib does not necessarily have to be an oval shape, and various cross-sectional shapes such as a substantially rectangular cross-section and a substantially rhombic cross-section can be appropriately employed.

  In addition, the reinforcing rib does not need to be formed in a certain cross-sectional shape. For example, in the annular reinforcing rib, the protruding height of the portion located outside the end of the short-circuit slit is equal to that of the short-circuit slit in the circumferential direction. The cross-sectional shape may be changed in the circumferential direction, such as being set larger than the protruding height of the portion located between the end portions. According to this, in the reinforcing rib, the portion where the protrusion height is set to be relatively large advantageously prevents the occurrence of cracks at the end of the short-circuit slit, while the portion where the protrusion height is set to be small causes cracks. It is possible to prevent stretching so as to wrap around a portion having a large protruding height, and it is possible to effectively prevent generation and elongation of a crack as a whole. In addition, it is possible to increase the degree of freedom in designing the rigidity of the movable rubber film as compared with an annular reinforcing rib formed with a substantially constant protrusion height. Needless to say, the width of the reinforcing rib may change in the length direction, and the change may change gradually or abruptly.

  The reinforcing ribs do not necessarily have the same shape on the front and back of the movable rubber film. Specifically, for example, the reinforcing rib is annular on the front side (pressure receiving chamber side) of the movable rubber film, and is partially provided only on the outer side of the end of the short-circuit slit on the back side (equilibrium chamber side). The cross-sectional shape may be different on the front and back sides.

  Further, as also shown in the first embodiment, the reinforcing rib is formed adjacent to the outside of the end of the short-circuit slit in order to effectively prevent the occurrence of cracks at the end of the short-circuit slit. However, the reinforcing rib and the short-circuit slit may be provided at a predetermined distance. In order to effectively exhibit the crack prevention effect, the separation distance between the reinforcing rib and the short-circuit slit is preferably 5 mm or less, more preferably 2 mm or less, and even more preferably 1 mm or less. . Thereby, the occurrence of cracks is advantageously prevented by the reinforcing ribs, and even when the reinforcing ribs are partially provided outside the ends of the short-circuit slits, the cracks can be prevented from progressing around the reinforcing ribs. It can be effectively prevented.

  Moreover, in said 1st embodiment, although the engine mount 10 for motor vehicles was shown as an example of the fluid enclosure type vibration isolator which concerns on this invention, this invention is not necessarily applied only to the engine mount for motor vehicles. It can be applied to various known fluid-filled vibration isolator. Further, the application range of the present invention is not necessarily limited to the fluid-filled vibration isolator for automobiles.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode to which various changes, modifications, improvements and the like are added based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the present invention.

It is a longitudinal cross-sectional view which shows the engine mount for motor vehicles as 1st embodiment of this invention, Comprising: II sectional drawing of FIG. The top view of the movable rubber film which comprises the engine mount of FIG. III-III sectional drawing of FIG. The top view of the movable rubber film which comprises the engine mount as 2nd embodiment of this invention. VV sectional drawing of FIG. The top view of the movable rubber film which comprises the engine mount as 3rd embodiment of this invention. The top view of the movable rubber film which comprises the engine mount as 4th embodiment of this invention. VIII-VIII sectional drawing of FIG. The top view of the movable rubber film which comprises the engine mount as 5th embodiment of this invention. The top view of the movable rubber film which comprises the engine mount as 6th embodiment of this invention. The top view of the movable rubber film which comprises the engine mount as 7th embodiment of this invention. The top view of the movable rubber film which comprises the engine mount as another one Embodiment of this invention. The top view of the movable rubber film which comprises the engine mount as another one Embodiment of this invention.

Explanation of symbols

10: Automotive engine mount, 12: First mounting bracket, 14: Second mounting bracket, 16: Rubber elastic body, 34: Diaphragm, 44: Partition member, 64: Movable rubber film, 72: Short-circuit slit, 74: crack prevention hole, 76: reinforcement rib, 78: pressure receiving chamber, 80: equilibrium chamber, 82: orifice passage, 98: stress relaxation hole

Claims (15)

The first attachment member and the second attachment member are connected by a main rubber elastic body, and one side of the partition member supported by the second attachment member is connected to the wall portion by the main rubber elastic body. A pressure receiving chamber having a portion is formed, and an equilibrium chamber in which a part of the wall portion is formed of a flexible film is formed on the other side of the partition member. In the fluid-filled vibration isolator in which an incompressible fluid is filled and an orifice passage that communicates the pressure receiving chamber and the equilibrium chamber is formed.
The partition member is assembled with a movable rubber film whose outer peripheral portion is fixedly supported by the partition member. The pressure of the pressure receiving chamber is applied to one surface of the movable rubber film and the other surface is While the pressure in the equilibrium chamber is exerted, a hydraulic pressure absorption mechanism is constructed that absorbs pressure fluctuations in the pressure receiving chamber by elastic deformation of the movable rubber film based on the pressure difference between the pressure receiving chamber and the equilibrium chamber. At least one slit is formed in the film, the slit is held closed by the elasticity of the movable rubber film, and the thickness direction of the movable rubber film is outside each end of the slit. A fluid-filled vibration isolator having reinforcing protrusions protruding toward both sides.   The fluid-filled vibration isolator according to claim 1, wherein the reinforcing protrusion extends in a direction orthogonal to an extension line of the slit.   The fluid-filled vibration isolator according to claim 2, wherein the reinforcing protrusion is formed in an annular shape that is continuous in a circumferential direction and surrounds the outer peripheral side of the slit.   The fluid-filled vibration isolator according to any one of claims 1 to 3, wherein a separation distance between an end of the slit and the reinforcing protrusion is 5 mm or less.   5. The fluid-filled vibration isolating apparatus according to claim 1, wherein a film thickness of the movable rubber film in an outer peripheral portion of the reinforcing protrusion gradually becomes thinner as it approaches the reinforcing protrusion. 6. apparatus.   The fluid-filled vibration isolator according to any one of claims 1 to 5, wherein a circular crack prevention hole penetrating the movable rubber film in a thickness direction is provided at an end of the slit.   The projected area in the axial direction of the crack prevention hole is 0.2% or more and 1.4% or less with respect to the projected area of a portion of the movable rubber film allowed to be elastically deformed. Fluid-filled vibration isolator.   The fluid filled type vibration damping device according to any one of claims 1 to 7, wherein at least a part of the slit is curved in a plan view of the movable rubber film.   The fluid-filled vibration isolator according to claim 8, wherein the slit has a curved portion extending in a curved manner and straight portions extending linearly from both ends of the curved portion.   The fluid-filled vibration isolator according to claim 8, wherein the slit is curved throughout.   The fluid-filled vibration isolator according to any one of claims 1 to 9, wherein the slit is bent in a plan view of the movable rubber film.   The fluid filled type vibration damping device according to claim 11, wherein a circular stress relaxation hole is provided in a bent portion of the slit.   The fluid-filled vibration isolator according to any one of claims 1 to 12, wherein the slit extends radially in three or more directions in a plan view of the movable rubber film.   The fluid-filled vibration isolator according to claim 13, wherein the slits are formed at equal intervals in the circumferential direction.   The fluid-filled type according to any one of claims 1 to 14, wherein the slits are formed at a plurality of positions with respect to the movable rubber film, and the reinforcing protrusions are respectively provided outside the slits. Anti-vibration device.

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