JP5520735B2 - Fluid-filled vibration isolator and manufacturing method thereof - Google Patents

Description

  The present invention relates to a fluid-filled vibration isolator that is suitably used for, for example, an automobile engine mount and exhibits a vibration-proof effect based on the flow action of a fluid enclosed therein, and a method for manufacturing the same. is there.

  2. Description of the Related Art Conventionally, a vibration isolator that is interposed between members that constitute a vibration transmission system and that anti-vibrate and connect these members is known, and application to an engine mount of an automobile or the like has been studied. As one type of vibration isolator, there are a pressure receiving chamber and an equilibrium chamber in which an incompressible fluid is sealed, and an orifice passage that connects the pressure receiving chamber and the equilibrium chamber to each other. There has also been proposed a fluid-filled vibration isolator in which a target vibration isolation effect is exhibited by fluid flowing between a pressure receiving chamber and an equilibrium chamber through a passage.

  Further, in Patent Document 1 (Japanese Patent Laid-Open No. 2007-16852), an opening that communicates the pressure receiving chamber and the equilibrium chamber when vibration is input at a frequency higher than that of the orifice passage is formed in the partition member. A structure has been proposed in which the blocking is switched by a movable plate. According to this, at the time of vibration input at a high frequency exceeding the tuning frequency of the orifice passage, the pressure receiving chamber and the equilibrium chamber are communicated through the opening, and the improvement of the vibration proof performance due to the low dynamic spring is realized. Anti-vibration effect is exhibited against vibrations in a wide frequency range.

  By the way, in the fluid filled type vibration isolator, it is known that an abnormal noise is generated when a shocking heavy load is input due to, for example, overcoming a step of a vehicle. It has become clear through repeated experiments and examinations that this abnormal noise is caused not only by the movable plate hitting the partition member but also due to cavitation. That is, when a significant negative pressure is exerted in the pressure receiving chamber by the input of a shocking large load, the gas dissolved in the incompressible fluid sealed in the pressure receiving chamber is separated to form bubbles. A shock wave is formed when the negative pressure in the pressure receiving chamber is reduced or eliminated and the bubble disappears, and the shock wave is propagated to the vehicle compartment, so that it is considered that abnormal noise is generated.

  However, in the fluid-filled vibration isolator described in Patent Document 1, no structure for preventing cavitation noise has been studied, and even if the impact sound caused by contact of the movable plate with the partition member is reduced. Still, it was not possible to realize sufficient silence.

  In addition, a structure that suppresses the occurrence of abnormal cavitation noise by forming a short-circuit hole in the partition member that short-circuits the pressure-receiving chamber and the equilibrium chamber when a shocking heavy load is input has been proposed. However, in such a structure, in order to effectively obtain the vibration isolation effect by the orifice passage, in addition to the opening switching mechanism, a valve body or the like that communicates the short-circuit hole only at the time of input of a heavy load in which cavitation is a problem. A switching mechanism is required. Therefore, there is a possibility that the increase in the number of parts, the complexity of the structure, the durability of the switching mechanism, and the like become problems.

JP 2007-16852 A

  The present invention has been made in the background of the above-mentioned circumstances, and the solution to the problem is the generation of a hitting sound caused by contact of the movable member with the partition member and cavitation with a small number of parts and a simple structure. It is an object of the present invention to provide a fluid-filled vibration isolator having a novel structure capable of effectively reducing or avoiding the occurrence of abnormal noise.

  Another object of the present invention is to provide a manufacturing method for efficiently manufacturing a fluid-filled vibration isolator having the excellent effects as described above.

In the first aspect of the present invention, the first mounting member and the second mounting member are connected by the main rubber elastic body, and the partition member is supported by the second mounting member. A pressure receiving chamber composed of the main rubber elastic body is formed on one side of the wall and a part of the wall is flexible on the other side of the partition member. A fluid in which an equilibrium chamber composed of a membrane is formed, an incompressible fluid is sealed in the pressure receiving chamber and the equilibrium chamber, and an orifice passage is formed to communicate the pressure receiving chamber and the equilibrium chamber with each other. In the enclosed vibration isolator, the movable plate is supported by the partition member so as to be minutely displaceable in the thickness direction, the pressure on the pressure receiving chamber side is exerted on one surface of the movable plate, and the equilibrium is applied on the other side. The pressure on the chamber side is applied and the movable Together but has a plurality of interconnected cells that open on both sides in the thickness direction is formed in the foam material, the opening area of the plurality of open cells in the surface of the receiving chamber side of the movable plate (S) is 40mm ² ≦ S ≦ 1500 mm ² , and the open cells are open on both surfaces of the movable plate in the thickness direction, and the open surfaces of the open cells are formed on the outer peripheral surface of the movable plate. A covering epidermis is formed .

  According to the fluid-filled vibration isolator having the structure according to the first aspect, the movable plate is a foam having open cells. Thereby, when the movable plate comes into contact with the partition member due to the relative pressure fluctuation between the pressure receiving chamber and the equilibrium chamber, it is possible to reduce the impact due to the impact and reduce or prevent the generation of the hitting sound.

  In addition, the bubbles formed on the movable plate are open cells and open on both sides of the movable plate. As a result, in a fluid-filled vibration isolator having a problem of cavitation, such as an automobile mount anti-vibration device such as an engine mount, when a shocking large load that may cause cavitation is input, the movable plate penetrates. The fluid flows from the equilibrium chamber to the pressure receiving chamber through the continuous bubbles. As a result, gas phase separation is reduced or avoided by relaxing the negative pressure in the pressure receiving chamber, and generation of abnormal noise due to cavitation can be effectively prevented.

  Further, the movable plate is made of a foam material, has air bubbles opening on the surface on the pressure receiving chamber side, and can be compressed and deformed. Therefore, when a shocking heavy load is input to the fluid-filled vibration isolator, the movable plate undergoes compressive deformation in the thickness direction based on the pressure difference between the pressure receiving chamber and the equilibrium chamber exerted on both surfaces of the movable plate. Easy to be born. Along with this compression deformation, the volume of open bubbles formed inside the movable plate is reduced, and the fluid retained in the inside is blown out to the pressure receiving chamber side. Based on the instantaneous blowout of fluid from the movable plate to the pressure receiving chamber side, the reduced pressure change caused in the pressure receiving chamber when a shocking heavy load is input is alleviated, so that an effect of suppressing cavitation can be expected.

In addition, the open cell formed on the movable plate has a total opening area (S) of 40 mm ² or more on the surface of the movable plate on the pressure receiving chamber side. As a result, the amount of fluid flowing into the pressure receiving chamber through the continuous bubbles when a shocking large load is input is sufficiently ensured, and the negative pressure in the pressure receiving chamber is effectively and quickly relieved. Can be effectively prevented.

Furthermore, since the sum (S) of the open areas of the open bubbles is set to 1500 mm ² or less, the flow resistance of each open cell is set sufficiently larger than the flow resistance of the orifice passage. As a result, it is possible to prevent the fluid flow amount through the orifice passage from decreasing due to the fluid flow through the continuous bubble or the ejection of the fluid from the continuous bubble, and the orifice passage is oscillated against the vibration in the frequency range in which the orifice passage is tuned. It is possible to effectively obtain a vibration isolation effect based on the fluid flow action through the passage.

  In particular, the open bubbles are formed so as to penetrate through a winding path rather than linearly penetrating the movable plate. As a result, fluid flow through continuous bubbles is less likely to occur, and during normal vibration input where vibration isolation effects are expected by the orifice passage, fluid flow through the orifice passage preferentially occurs and the desired vibration isolation is achieved. The effect is exhibited effectively. On the other hand, when a significant pressure difference occurs between the pressure receiving chamber and the equilibrium chamber due to the input of a large load that can cause cavitation, the fluid flow through the open bubbles is sufficiently generated. Occurrence of noise caused by cavitation is prevented.

In addition, according to the first aspect, since the outer peripheral surface of the movable plate made of foam is constituted by the skin, a certain degree of rigidity is imparted to the movable plate, and the shape stability is improved. As a result, the movable plate is stably supported by the partition member, and the movable plate is held in the initial arrangement state.

According to a second aspect of the present invention, in the fluid-filled vibration isolator described in the first aspect, the movable plate is formed of foamed rubber.

According to the second aspect, since the movable plate is formed of foamed rubber, it is possible to easily realize a movable plate excellent in impact absorption performance, durability performance, and the like.

According to a third aspect of the present invention, in the fluid-filled vibration isolator described in the first or second aspect, a reinforcing member is fixed to the movable plate.

According to the third aspect, since the movable plate is reinforced by the reinforcing member, the deformation of the movable plate due to the action of hydraulic pressure is limited, and the shape stability of the movable plate is ensured. Therefore, dropping from the partition member due to deformation of the movable plate is prevented, and the initial mounting state is stably maintained.

A fourth aspect of the present invention is a method of manufacturing the fluid-filled vibration isolator described in any one of the first to third aspects, the columnar shape obtained by molding a foam material The movable plate is obtained by cutting out the foamed member at predetermined thicknesses in the axial direction.

According to the manufacturing method of the fluid-filled vibration isolator according to the fourth aspect as described above, since the skin is formed on the surface of the foamed member formed by molding, the foamed member is cut out for each predetermined thickness. Thus, it is possible to easily obtain a movable plate whose outer peripheral surface is constituted by a skin. In addition, since a plurality of movable plates can be obtained from a single molded product (foamed member), the production efficiency can be improved.

A fifth aspect of the present invention is a method of manufacturing the fluid-filled vibration isolator described in any one of the first to third aspects, wherein the movable plate is compressed and deformed in an incompressible fluid. After the air in the open bubbles is removed, the movable plate is assembled and disposed in the incompressible fluid.

According to the manufacturing method of the fluid filled type vibration damping device according to the fifth aspect as described above, the movable plate is compressed and deformed in the incompressible fluid, and the air held by the bubbles of the movable plate is extracted in advance before assembling. Thus, air can be prevented from entering the pressure receiving chamber and the equilibrium chamber. Therefore, at the time of normal vibration input, it is possible to prevent fluctuations in the internal pressure of the pressure receiving chamber due to the compressibility of air, and to secure the amount of fluid flowing through the orifice passage. As a result, it is possible to sufficiently obtain a vibration isolation effect based on the fluid flow action.

  According to the present invention, the movable plate is formed of a foam material and has a plurality of open cells that open on both sides, so that the vibration isolation effect by the orifice passage can be effectively obtained during normal vibration input. The negative pressure in the pressure receiving chamber can be reduced by the fluid flow through the continuous bubbles when a large load that can cause cavitation is input, and the generation of abnormal noise due to cavitation can be prevented. In addition, since the movable plate is formed of a foam material, the hitting sound generated when the movable plate comes into contact with another member such as a partition member is also reduced.

The longitudinal cross-sectional view which shows the engine mount as 1st embodiment of this invention. The perspective view which expands and shows the movable rubber plate which comprises the engine mount shown by FIG. The longitudinal cross-sectional view of the movable rubber board shown by FIG. It is a longitudinal cross-sectional view explaining the manufacturing method of the movable rubber plate shown by FIG. 2, Comprising: The figure which shows the formation process of a foaming member. It is a perspective view explaining the manufacturing method of the movable rubber plate shown by FIG. 2, Comprising: The figure which shows the process of cut | disconnecting a foaming member and forming a movable rubber plate. The graph which shows the level of the contact sound generated in the engine mount shown by FIG. The graph which shows the level of the cavitation noise which generate | occur | produces in the engine mount shown by FIG. The longitudinal cross-sectional view which expands and shows the principal part of the engine mount as 2nd embodiment of this invention. The longitudinal cross-sectional view which expands and shows the principal part of the engine mount as 3rd embodiment of this invention. The longitudinal cross-sectional view which expands and shows the principal part of the engine mount as another embodiment of this invention.

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

  FIG. 1 shows an engine mount 10 for an automobile as a first embodiment of a fluid filled type vibration damping device having a structure according to the present invention. The engine mount 10 has a structure in which a first attachment member 12 and a second attachment member 14 are connected by a main rubber elastic body 16, and the first attachment member 12 is attached to a power unit (not shown), The second attachment member 14 is attached to a vehicle body (not shown). In the following description, the vertical direction means, in principle, the vertical direction in FIG. 1, which is the main vibration input direction.

  More specifically, the first mounting member 12 is integrally formed with a fixing portion 18 that has a substantially inverted truncated cone shape and a flange-shaped portion 20 that protrudes from the upper end of the fixing portion 18 toward the outer peripheral side. Have a structure. Further, the first mounting member 12 includes a mounting bolt 22 that protrudes upward from the upper end of the fixing portion 18 on the central axis. Further, the inner bracket 24 is superimposed on the first mounting member 12 from above and is fixed by screwing a nut 26 to the mounting bolt 22. The first mounting member 12 is attached to the power unit by fixing the inner bracket 24 to a power unit (not shown) with a bolt or the like.

  The second mounting member 14 has a thin-walled, large-diameter, generally cylindrical shape, and its upper end is bent toward the outer peripheral side and its lower end is bent toward the inner peripheral side. A cylindrical outer bracket 28 is externally inserted into the second mounting member 14. And the fixing piece 30 provided in the lower end of the outer bracket 28 is fixed to a vehicle body (not shown) with a bolt or the like, so that the second attachment member 14 is attached to the vehicle body.

  The first mounting member 12 and the second mounting member 14 are arranged on the same central axis at a predetermined distance in the vertical direction, and the first mounting member 12 and the second mounting member 14 are elastic on the main body. The body 16 is elastically connected. The main rubber elastic body 16 has a thick-walled large-diameter substantially truncated cone shape, and a small-diameter side end portion is vulcanized and bonded to the lower surface of the fixing portion 18 and the flange-shaped portion 20 of the first mounting member 12. In addition, the outer peripheral surface of the end portion on the large diameter side is superimposed on the inner peripheral surface of the second mounting member 14 and vulcanized and bonded. As described above, the main rubber elastic body 16 of the present embodiment is formed as an integrally vulcanized molded product including the first mounting member 12 and the second mounting member 14.

  A large-diameter recess 32 that opens to the large-diameter side end face is formed at the radial center of the main rubber elastic body 16. The large-diameter recess 32 has a substantially cylindrical shape with an opening portion (lower portion) having a substantially constant diameter, and a bottom portion (upper portion) having a substantially truncated cone shape with a gradually decreasing diameter toward the upper side. It is a recess having a generally mortar shape in the reverse direction as a whole. A seal rubber layer 34 is integrally formed at the outer peripheral end of the main rubber elastic body 16. The seal rubber layer 34 has a thin-walled, large-diameter, generally cylindrical shape, and protrudes downward from a portion where the large-diameter recess 32 in the main rubber elastic body 16 is deviated to the outer peripheral side.

  A flexible film 36 is attached to the second attachment member 14. The flexible film 36 is formed of a thin circular rubber film and has sufficient slackness in the axial direction. Further, the outer peripheral edge portion of the flexible film 36 is vulcanized and bonded to an annular fixing member 38, and the fixing member 38 is inserted into the lower end portion of the second mounting member 14, and is attached to the second mounting member 14. The flexible film 36 is attached to the second attachment member 14 by performing diameter reduction processing such as eight-way drawing. In addition, the lower end of the second mounting member 14 bent to the inner peripheral side is overlapped with the fixing member 38 from below in the axial direction by performing the diameter reduction processing on the second mounting member 14.

  When the flexible film 36 is attached to the second attachment member 14, the second attachment member 14 has an upper opening that is fluid-tightly closed by the main rubber elastic body 16 and a lower side. Are closed fluid-tightly by the flexible membrane 36. As a result, a fluid sealed region 40 is formed between the main rubber elastic body 16 and the flexible membrane 36 in the axial direction opposite from each other, and an incompressible fluid is sealed in the fluid sealed region 40. Has been. The incompressible fluid sealed in the fluid sealing region 40 is not particularly limited, but water, alkylene glycol, polyalkylene glycol, silicone oil, or a mixture thereof is preferably used. . In particular, a low-viscosity fluid having a viscosity of 0.1 Pa · s or less is desirable in order to effectively obtain an anti-vibration effect based on the fluid flow action described below.

  A partition member 42 is disposed in the fluid sealing region 40. The partition member 42 has a thick and large diameter substantially disk shape as a whole, and includes a partition member main body 44 and a lid member 46.

  The partition member main body 44 is formed of a metal such as an aluminum alloy, a hard synthetic resin, or the like, and has a substantially disk shape with a large thickness and a large diameter. In addition, a substantially cylindrical accommodation recess 48 opened on the upper surface and a substantially cylindrical central recess 50 opened on the lower surface are formed in the radially central portion of the partition member main body 44. Is thin. Furthermore, a circumferential groove 52 continuously extending with a predetermined length of slightly less than two rounds in the circumferential direction is formed on the outer peripheral edge of the partition member main body 44 so as to open to the outer circumferential surface. A plurality of pins 54 projecting upward are integrally formed between the receiving recess 48 of the partition member main body 44 and the radial direction of the circumferential groove 52.

  The lid member 46 is thin and has a substantially disk shape having a smaller diameter than the partition member main body 44, and is a hard member formed of the same material as the partition member main body 44. The lid member 46 has a larger diameter than the housing recess 48 formed in the partition member main body 44, and extends to the outer peripheral side from the position where the pin 54 is formed in the partition member main body 44. Note that an insertion hole 56 is formed at a position corresponding to the pin 54 of the partition member main body 44 in the radial intermediate portion of the lid member 46 so as to penetrate in the plate thickness direction.

  The lid member 46 is overlapped with the partition member main body 44 from above in the axial direction, and the pin 54 of the partition member main body 44 is inserted into the insertion hole 56 of the lid member 46 and then penetrates the lid member 46. The lid member 46 is fixed to the partition member main body 44 by the tip portion of the pin 54 protruding upward being crushed in the axial direction and expanding in diameter. Further, by attaching the lid member 46 to the partition member main body 44, the opening of the accommodation recess 48 is covered with the lid member 46, and a space is formed inside the partition member 42.

  The partition member 42 having such a structure is accommodated in the fluid sealing region 40. That is, the partition member 42 is inserted into the inner peripheral side of the second mounting member 14 and disposed between the axially opposed surfaces of the main rubber elastic body 16 and the flexible film 36, and then the second mounting member 42. The member 14 is fixed to the second mounting member 14 by being subjected to diameter reduction processing. The partition member 42 is positioned vertically in the axial direction by overlapping the upper surface of the outer peripheral edge portion with the lower surface of the main rubber elastic body 16 and overlapping the lower surface of the outer peripheral edge portion with the upper surface of the fixing member 38. ing.

  In this way, the partition member 42 is supported by the second mounting member 14 and disposed so as to extend in the direction perpendicular to the axis in the fluid sealing region 40, so that the fluid sealing region 40 sandwiches the partition member 42. Divided up and down. That is, on the upper side in the axial direction across the partition member 42, a part of the wall portion is formed of the main rubber elastic body 16, and a pressure receiving chamber 58 is formed in which an internal pressure fluctuation is exerted when vibration is input. On the other hand, on the lower side in the axial direction across the partition member 42, an equilibrium chamber 60 is formed in which a part of the wall portion is formed of the flexible film 36 and volume change is easily allowed. The pressure receiving chamber 58 and the equilibrium chamber 60 are filled with the incompressible fluid sealed in the fluid sealing region 40.

In the present embodiment, the wall spring stiffness (K) of the pressure receiving chamber 58 is preferably set in a range of 100 N / mm ≦ K ≦ 1000 N / mm. Further, preferably, the volume (V) of the pressure receiving chamber 58 is set in a range of 20 cm ³ ≦ V ≦ 200 cm ³ .

  Further, the outer peripheral surface of the partition member 42 is fluid-tightly overlapped with the inner peripheral surface of the second mounting member 14 via the seal rubber layer 34, so that the opening of the circumferential groove 52 is covered with the second mounting member 14. Thus, a tunnel-like flow path extending in the circumferential direction is formed. Further, one end portion in the length direction of the circumferential groove 52 is communicated with the pressure receiving chamber 58 through an upper communication hole (not shown), and the other end portion in the length direction of the circumferential groove 52 is communicated with the equilibrium chamber through a lower communication hole (not shown). 60. As a result, an orifice passage 62 that connects the pressure receiving chamber 58 and the equilibrium chamber 60 to each other is formed in the partition member 42 using the circumferential groove 52. This orifice passage 62 adjusts the ratio (A / L) of the passage cross-sectional area (A) to the passage length (L) while taking into account the wall spring rigidity of the fluid sealing region 40, thereby corresponding to an engine shake of 10 Hz. It is tuned so that the fluid flows in a resonance state when a low frequency vibration of a certain level is input.

  A movable rubber plate 64 as a movable plate is supported by the partition member 42. The movable rubber plate 64 has a substantially disc shape as shown in FIGS. 2 and 3, and is accommodated in the accommodation recess 48 of the partition member 42 as shown in FIG. ing. The movable rubber plate 64 has a thickness dimension slightly smaller than the depth dimension of the receiving recess 48 and an outer diameter dimension slightly smaller than the inner diameter dimension of the receiving recess 48. Small displacements in the axial direction are allowed without being hindered by friction or the like on the outer peripheral surface. The diameter (R) of the movable rubber plate 64 is preferably set in the range of 20 mm ≦ R ≦ 100 mm, and in this embodiment, R = 40 mm.

  The movable rubber plate 64 disposed in the housing recess 48 is subjected to either the pressure in the pressure receiving chamber 58 or the pressure in the equilibrium chamber 60 on both surfaces in the thickness direction. That is, a plurality of upper through holes 66 are formed in a portion of the lid member 46 that covers the accommodation recess 48, and the hydraulic pressure in the pressure receiving chamber 58 is applied to the upper surface of the movable rubber plate 64 through the upper through holes 66. ing. On the other hand, a plurality of lower through holes 68 are formed in the bottom wall portion of the housing recess 48 in the partition member main body 44 so that the hydraulic pressure in the equilibrium chamber 60 is exerted on the lower surface of the movable rubber plate 64 through the lower through holes 68. It has become. Accordingly, the movable rubber plate 64 can be slightly displaced vertically in the axial direction based on the relative pressure difference between the pressure receiving chamber 58 and the equilibrium chamber 60 at the time of vibration input.

  Moreover, the movable rubber plate 64 is formed of a foam material as shown in FIGS. 2 and 3, and is formed of foam rubber in this embodiment. Foam rubber is, for example, a rubber material generally used in vibration isolators such as natural rubber (NR) and butadiene rubber (BR), which is foamed at a predetermined expansion ratio by adding a foaming agent. Say. In addition, the movable rubber plate 64 is easily deformed by the action of external force by being formed of a foam material, and in particular, by being formed of foam rubber, elastic deformation occurs. ing.

  In addition, a large number of fine open cells are formed on the movable rubber plate 64 formed of a foam material, and the movable rubber plate 64 is added to these open cells as the open cell 70 shown in FIG. Those that penetrate in the axial direction are included. A large number of bubbles including open bubbles 70 are opened on the surface of the movable rubber plate 64 on the pressure receiving chamber 58 side. FIG. 3 is a diagram showing the movable rubber plate 64 as a model so that the structure can be easily understood. The bubble ratio (foaming ratio), how the bubbles are connected, and the like are different from actual ones. .

Further, the total open area (S) of the open bubbles 70 on the surface of the movable rubber plate 64 on the pressure receiving chamber 58 side is set in a range of 40 mm ² ≦ S ≦ 1500 mm ^{2. In} this embodiment, S = It is set to 65 mm ² . When the open area (S) of the open cell 70 is smaller than 40 mm ^{2, the} amount of fluid flow through the open cell 70 is not sufficiently secured when a large load that may cause cavitation, which will be described later, is input. The reduction effect is insufficient. On the other hand, when the opening area (S) of the continuous bubble 70 is larger than 1500 mm ² , the fluid pressure through the continuous bubble 70 causes the pressure receiving chamber 58 to flow even during normal vibration input in which the vibration isolation effect by the orifice passage 62 is to be exhibited. This is because the pressure difference in the equilibrium chamber 60 is reduced more than necessary, and the vibration isolation effect by the orifice passage 62 is not sufficiently exhibited, and the vibration isolation performance is adversely affected. In the present embodiment, the open cell 70 has a total opening area on the surface of the movable rubber plate 64 on the equilibrium chamber 60 side within the same numerical range as the total opening area on the surface on the pressure receiving chamber 58 side ( 40 mm ² or more and 1500 mm ² or less).

In addition, the open cell 70 preferably has a minimum cross-sectional area (a) set in a range of 0.01 mm ² ≦ a ≦ 5 mm ² , more preferably in a range of 0.05 mm ² ≦ a ≦ 1 mm ² . Set to Furthermore, the sum total of the minimum values (a) of the cross-sectional areas of the open cells 70 is set to 40 mm ² or more.

  Further, the length (l) of the continuous bubble 70 is shorter than the length (L) of the orifice passage 62 and is more than 1/25 times the length (L) of the orifice passage 62 (L / 25 ≦ l <L ), And more preferably 1/10 times or more (L / 10 ≦ l <L). Further, since the open cell 70 extends while curving or bending inside the movable rubber plate 64, its length (1) is larger than the thickness dimension of the movable rubber plate 64.

  The ratio (a / l) between the cross-sectional area (a) and the length (l) of each open cell 70 is set smaller than the ratio (A / L) between the cross-sectional area and the length of the orifice passage 62 (A / L). The flow resistance of the continuous bubble 70 is larger than the flow resistance of the orifice passage 62. The ratio of the cross-sectional area and the length of each open cell 70 is preferably set in the range of a / l ≦ A / 4L, more preferably in the range of a / l ≦ A / 9L. ing. Furthermore, the ratio between the cross-sectional area and the length of each open cell 70 is preferably set in the range of A / 36L ≦ a / l, and more preferably in the range of A / 30L ≦ a / l. ing.

  Also, bubbles are exposed and open on both axial surfaces of the movable rubber plate 64, while a smooth skin 72 is formed on the outer peripheral surface of the movable rubber plate 64 to cover the opening of the bubbles. Yes. As a result, the rigidity of the movable rubber plate 64 formed of a foam material is secured to some extent by the skin 72, and the deformation amount of the movable rubber plate 64 is limited to ensure the shape stability.

  The engine mount 10 having such a structure is manufactured as follows, for example.

  First, the first mounting member 12 and the second mounting member 14 are prepared in advance, and the first mounting member 12 and the second mounting member 14 are set in a mold for molding the main rubber elastic body 16 (not shown). To do. Thereafter, a rubber material is filled into the cavity of the molding die, and the main rubber elastic body 16 is formed as an integrally vulcanized molded product including the first mounting member 12 and the second mounting member 14. Thereby, the formation process of the main rubber elastic body 16 is completed.

  Also, the flexible member 36 is fixed to the fixing member 38 by setting the fixing member 38 prepared in advance in a molding die of the flexible membrane 36 and filling the cavity of the molding die with a rubber material. It is formed as an integrally vulcanized molded product with Thereby, the formation process of the flexible film | membrane 36 is completed.

  Further, the movable rubber plate 64 is formed as shown in FIGS. That is, first, as shown in FIG. 4, a molding die 78 for the movable rubber plate 64 in which the first molding die 74 and the second molding die 76 are combined is prepared and molded. A cylindrical foam member 80 is formed by filling the cavity of the metal mold 78 with a foam rubber material. The foamed member 80 has a porous structure having a large number of open cells 70 inside, and a skin 72 where no bubbles are opened is formed on the surface. Thereafter, the foam member 80 taken out from the molding die 78 is cut out at a predetermined thickness in the axial direction as shown by a two-dot chain line in FIG. A rubber plate 64 is formed. By making the foam member 80 into a ring shape in this way, it is possible to easily obtain the movable rubber plate 64 having both porous surfaces in the axial direction and the outer skin 72 having the outer skin 72. The formation process of the movable rubber plate 64 is thus completed.

  The movable rubber plate 64 formed in this way is put in a water tank filled with an incompressible fluid together with the partition member main body 44 and the lid member 46 prepared in advance, and the partition member 42 is in the incompressible fluid. Assembled.

  More specifically, first, the movable rubber plate 64 is placed in a water tank filled with an incompressible fluid, and the movable rubber plate 64 is compressed and deformed by hand or the like in the incompressible fluid. At this time, it is desirable that the entire movable rubber plate 64 is compressed. Preferably, the entire movable rubber plate 64 is compressed and deformed at least once by being crushed a plurality of times as necessary. As a result, the air retained inside the porous movable rubber plate 64 is released and filled with the incompressible fluid. Thus, the degassing step of the movable rubber plate 64 is completed.

  Next, after putting the partition member main body 44 and the lid member 46 in the water tank and inserting the movable rubber plate 64 into the accommodation recess 48 of the partition member main body 44 in the incompressible fluid, the lid is also covered in the incompressible fluid. The member 46 is assembled to the partition member main body 44 to form the partition member 42 in which the movable rubber plate 64 is accommodated. Thus, the assembly process of the partition member 42 is completed.

  Then, an integrated vulcanized molded product of the main rubber elastic body 16 and an integrated vulcanized molded product of the flexible membrane 36 are put into a water tank containing the partition member 42, so that an integrated vulcanized molded product of the main rubber elastic body 16 is obtained. After the partition member 42 is inserted, the integrally vulcanized molded product of the flexible film 36 is inserted into the integrally vulcanized molded product of the main rubber elastic body 16. Thus, the temporary assembly process is completed. The partition member 42 and the fixing member 38 are both temporarily fixed by insertion into the second mounting member 14 and fall off from the integrally vulcanized molded product of the main rubber elastic body 16. It is desirable to be positioned without any problems.

  Then, the temporarily vulcanized molded product of the main rubber elastic body 16 and the integrally vulcanized molded product of the partition member 42 and the flexible membrane 36 are taken out from the water tank, and the second mounting member 14 is subjected to diameter reduction processing. By applying, the integral vulcanization molded product and the partition member 42 are fixed. Thus, the mount assembly process is completed, and the manufacturing process of the engine mount 10 is completed as described above.

  In addition to the above steps, by providing a mounting step of the inner bracket 24 and the outer bracket 28, it is possible to obtain the engine mount 10 in the bracket mounting state as shown in FIG.

  When a low-frequency large-amplitude vibration corresponding to an engine shake is input while the engine mount 10 having such a structure is mounted on a vehicle, a relative pressure difference between the pressure receiving chamber 58 and the equilibrium chamber 60 is generated. Induced. As a result, the fluid flows between the chambers 58 and 60 through the orifice passage 62, and the intended vibration isolation effect (high damping effect) based on the fluid action such as the resonance action of the fluid is exhibited.

  Further, at the time of inputting the low frequency large amplitude vibration, the movable rubber plate 64 is pressed against the bottom wall portion of the housing recess 48 or the lid member 46 and either the upper through hole 66 or the lower through hole 68 is closed. Thereby, the fluid flow between the pressure receiving chamber 58 and the equilibrium chamber 60 through the upper and lower through holes 66 and 68 is substantially blocked by the movable rubber plate 64, and the amount of fluid flowing through the orifice passage 62 is efficient. Secured.

  In this case, since the movable rubber plate 64 is a porous material formed of a foam material, the impact when the movable rubber plate 64 strikes the partition member 42 is alleviated, and the contact sound is reduced or avoided. Is done. In addition, since the outer skin 72 is formed on the outer peripheral surface of the movable rubber plate 64, the shape stability of the movable rubber plate 64 is ensured, and the upper and lower through holes 66, 68 are formed when contacting the partition member 42. It is designed to cover stably.

  In addition, when a medium to high frequency vibration (vibration having a frequency higher than the tuning frequency of the orifice passage 62) corresponding to idling vibration or running noise is input, the orifice passage 62 is substantially clogged due to anti-resonance. . Here, the movable rubber plate 64 is slightly displaced up and down in a resonance state, whereby the pressure receiving chamber 58 and the equilibrium chamber 60 are communicated with each other through the upper through hole 66 and the lower through hole 68. As a result, a low dynamic spring is achieved, and the intended vibration isolation effect (vibration insulation effect) is effectively exhibited.

  On the other hand, when a shocking large load (large amplitude vibration) is input when overcoming a step, the pressure in the pressure receiving chamber 58 is significantly reduced locally. In the engine mount 10, a plurality of open bubbles 70 are formed in the movable rubber plate 64 and penetrate the movable rubber plate 64 up and down. As a result, when a large pressure difference is generated between the pressure receiving chamber 58 and the equilibrium chamber 60, fluid flows between the pressure receiving chamber 58 and the equilibrium chamber 60 through the continuous bubble 70, and the pressure drop in the pressure receiving chamber 58 is quickly reduced. Alleviated. As a result, the generation of bubbles due to cavitation is reduced or avoided, and the generation of noise due to the collapse of the bubbles is prevented. Even when a large load causing cavitation is a problem, the movable rubber plate 64 is made porous, so that the hitting sound caused by contact with the partition member 42 is reduced or avoided. .

  In addition, when a large load is input, the movable rubber plate 64 is pressed against the lid member 46 based on the relative pressure difference between the pressure receiving chamber 58 and the equilibrium chamber 60. As a result, the movable rubber plate 64 is compressed and deformed in the thickness direction, the volume of bubbles opening on the surface of the movable rubber plate 64 on the pressure receiving chamber 58 side is reduced, and the fluid retained in the bubbles is received by pressure. It will flow into the chamber 58 side. As a result, the negative pressure exerted on the pressure receiving chamber 58 when a heavy load is input is quickly relieved, thereby preventing the occurrence of cavitation and the accompanying noise.

  In addition, the movable rubber plate 64 is attached to the partition member 42 in a state in which the movable rubber plate 64 is compressed and deformed in advance in an incompressible fluid and air in the open bubbles 70 is removed. Therefore, even if the movable rubber plate 64 is pressed against the partition member 42 and compressed and deformed, the bubbles are not released from the continuous bubbles 70 into the fluid sealing region 40, and the bubbles accumulate in the pressure receiving chamber 58. Problems such as a decrease in piston efficiency are avoided.

  Further, each of the open bubbles 70 has a very small cross-sectional area and a relatively long flow path length, and the flow resistance is set sufficiently larger than that of the orifice passage 62. Therefore, when normal low frequency vibration is input, fluid flow through the orifice passage 62 is preferentially generated, and the vibration isolation effect by the orifice passage 62 is effectively exhibited. In particular, since the open cell 70 has a complicatedly bent or curved hole shape, the flow resistance is larger, and the vibration isolation effect by the orifice passage 62 is prevented from being adversely affected. Yes.

  In addition, it is shown in the graph of the experimental result shown in FIG. 6 that the contact sound of the movable rubber plate 64 is reduced in the engine mount 10 of the present embodiment. That is, the contact sound of the engine mount 10 (example) of the present embodiment indicated by the solid line in FIG. 6 is the same as that of the engine mount (comparative example) of the conventional structure indicated by the one-dot chain line in FIG. It is kept low against the hitting sound. Thus, it is clear from the experimental results that the fluid-filled vibration isolator according to the present invention can effectively reduce the contact sound of the movable rubber plate.

  Moreover, the graph of the experimental result shown by FIG. 7 has shown that the noise by cavitation is reduced in the engine mount 10 of this embodiment. That is, the cavitation noise of the engine mount 10 (example) of the present embodiment shown by the solid line in FIG. 7 is the cavitation noise of the engine mount (comparative example) of the conventional structure shown by the dashed line in FIG. It is kept small enough for the sound. As described above, the experimental results also show that the fluid-filled vibration isolator according to the present invention can effectively reduce abnormal noise due to cavitation. 6 and 7, the conventional engine mount (comparative example) is a solid engine instead of the movable rubber plate 64 in the engine mount having the same structure as the engine mount 10. This refers to a movable plate made of a rubber elastic body.

  Next, FIG. 8 shows a main part of an engine mount as a second embodiment of the present invention. That is, in FIG. 8, a movable rubber plate 92 as a movable plate is accommodated in the partition member 90. In the following description, members and parts that are substantially the same as those of the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.

  The movable rubber plate 92 is formed of foamed rubber having open cells 70, like the movable rubber plate 64 of the first embodiment. A reinforcing member 94 is vulcanized and bonded to the movable rubber plate 92. The reinforcing member 94 is a member having higher rigidity than foamed rubber formed of metal such as iron or aluminum alloy or hard synthetic resin. The reinforcing member 94 has a substantially annular shape extending in the circumferential direction with a substantially constant cross-sectional shape, and has a concave groove 95 opened on the outer peripheral surface.

  The movable rubber plate 92 provided with such a reinforcing member 94 is formed as follows, for example. That is, first, a reinforcing member 94 having a predetermined shape prepared in advance is set in a molding die. At this time, the reinforcing member 94 is positioned with respect to the molding die by inserting a convex portion provided in the molding die into the concave groove 95 of the reinforcing member 94. Then, the foamed member is formed by filling the cavity of the molding die with the foamed rubber material and performing vulcanization molding. Thereafter, both surfaces of the foamed member taken out from the molding die are cut into round pieces, whereby a movable rubber plate 92 having both axial surfaces porous and a skin 72 formed on the outer peripheral surface can be obtained. A plurality of reinforcing members 94 are set in a molding die so as to be separated from each other by a predetermined distance in the axial direction, and a columnar foam member having a plurality of reinforcing members 94 is formed. A plurality of movable rubber plates 92 can also be efficiently formed by cutting out the foamed member every predetermined thickness in the axial direction so as to have 94.

  The movable rubber plate 92 is arranged in the same arrangement area as that of the first embodiment provided in the partition member 90. At this time, as also shown in the first embodiment, it is desirable to compress and deform the movable rubber plate 92 in the incompressible fluid so that the air in the open cell 70 is removed before assembly. . In the partition member 90 of the present embodiment, the upper through hole 96 formed in the upper wall portion of the movable rubber plate 92 and the lower through hole 98 formed in the lower wall portion both have a large diameter. It is a circular hole. The upper and lower through holes 96 and 98 are both larger than the inner diameter of the reinforcing member 94 and smaller than the outer diameter, and one each is formed.

  According to the engine mount provided with the movable rubber plate 92 having the structure according to the present embodiment, the vibration isolation by the orifice passage 62 is provided without providing a special valve body or the like, similarly to the engine mount of the first embodiment. Both the effect and the effect of reducing the contact sound and cavitation noise can be obtained effectively.

  Further, when the reinforcing member 94 is fixed to the movable rubber plate 92, the deformation of the movable rubber plate 92 is restricted, and the large-diameter upper through hole 96 and the lower through hole 98 are formed in the partition member 90. In addition, the movable rubber plate 92 is held without coming out of the arrangement region. Therefore, the amount of fluid flowing between the pressure receiving chamber 58 and the equilibrium chamber 60 through the upper through hole 96 and the lower through hole 98 can be increased, and the vibration insulation effect that is exhibited when the medium to high frequency vibration is input. Can be obtained more effectively.

  In addition, since the reinforcing member 94 is annular and the center hole of the reinforcing member 94 is filled with foamed rubber, the open cell 70 penetrating the movable rubber plate 92 vertically is formed in the central hole of the reinforcing member 94. It has become so. Therefore, the reinforcing member 94 is disposed without hindering the effect of preventing abnormal cavitation noise, and the above-described improvement in the vibration isolation performance is realized.

  Next, FIG. 9 shows a main part of an engine mount as a third embodiment of the present invention. That is, in FIG. 9, a movable rubber plate 102 as a movable plate is assembled to the partition member 100.

  The movable rubber plate 102 is a generally disk-shaped member formed of foamed rubber having a large number of open cells, and has both end portions in the axial direction having a large diameter and the center portion in the axial direction at both end portions. The diameter is smaller than that. In addition, annular reinforcing members 94 are fixed to the outer peripheral portions at both ends in the axial direction having a large diameter, and face each other with a predetermined distance in the axial direction. In addition, the movable rubber plate 102 of this embodiment is the open cell which penetrates the movable rubber plate 102 using the center hole of a pair of reinforcement members 94 and 94 similarly to the movable rubber plate 92 of 2nd embodiment. 70 is formed. Similarly to the movable rubber plate 92 of the second embodiment, the outer periphery is obtained by performing a foaming member molding process using a mold and a cutting (ring cutting) process in which the foaming member is cut in a predetermined thickness in the axial direction. It is possible to easily obtain the movable rubber plate 102 having the skin 72 on the surface and having the open cells 70 open on both axial surfaces.

  The movable rubber plate 102 is attached to the partition member 100 by the support protrusion 104 formed on the partition member 100 being sandwiched between the opposing surfaces of the pair of reinforcing brackets 94, 94. Since the thickness dimension of the support protrusion 104 is made smaller than the separation distance of the foam rubber fixed to the opposing surfaces of the pair of reinforcing members 94, 94, the movable rubber plate 102 is paired with respect to the partition member 100. A small displacement is allowed in the opposing direction of the reinforcing members 94, 94. In the present embodiment, it is desirable that the partitioning member 100 (supporting protrusion 104) has a divided structure, for example, to facilitate the assembly of the movable rubber plate 102 to the supporting protrusion 104.

  Thus, not only the movable rubber plates 64 and 102 accommodated and arranged in the partition members 42 and 100 as shown in the first and second embodiments, but also movable rubbers having different mounting modes on the partition members. The present invention can also be applied to the plate 102.

  A movable rubber plate 110 as a movable plate having a structure in which the pair of reinforcing members 94, 94 are omitted from the movable rubber plate 102 of the third embodiment as shown in FIG. 10 can also be employed. In short, even in the structure in which the movable rubber plate 110 made of a single foam rubber is assembled to the partition member 100 so as to sandwich the support protrusion 104 as in the third embodiment, the excellent effects of the present invention (such as noise reduction effect) ) Is effectively demonstrated.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, the movable plate may be formed of a foam material and have open cells penetrating in the thickness direction, and the formation material is not limited to foam rubber. Specifically, for example, a material selected from various polymer foams including foamed plastics such as urethane foam in consideration of liquid resistance can be adopted as the material of the movable plate.

  In addition, the movable plate does not necessarily have to have a skin whose outer peripheral surface does not open with bubbles, and the entire surface may be porous and open with bubbles. Such a movable plate having a porous surface as a whole can be formed, for example, by punching a plate-like foam member having both surfaces in the thickness direction into a predetermined shape.

  The shape of the reinforcing member shown in the second and third embodiments is not limited to an annular shape. Specifically, for example, a plate-shaped reinforcing member in which a plurality of holes that penetrate the radial intermediate portion in the thickness direction is employed, and the open cells pass through the movable plate through the plurality of holes. It may be formed, or a plurality of reinforcing members may be intermittently disposed on the periphery of the movable plate.

  Furthermore, the reinforcing member does not necessarily need to be embedded in the middle of the movable plate in the thickness direction, and may be fixed in a state of being superimposed on the end surface in the thickness direction of the movable plate formed of a foam material.

  In addition, it is desirable that the movable plate be assembled to the partition member after the air retained therein is removed by compressive deformation in an incompressible fluid, but it is not always necessary to remove the entire amount of air, and the required prevention is required. As long as the vibration performance can be satisfied, it is not particularly problematic for air to enter the pressure receiving chamber and the equilibrium chamber. If the required vibration-proof performance can be satisfied, the movable plate may be assembled to the partition member without removing the air, or the air is removed by suction, pressurization, or immersion in an incompressible fluid. May be.

  The present invention is not only applied to engine mounts, but also suitably applied to body mounts, subframe mounts, differential mounts, and the like. Further, the present invention can be applied not only to a fluid-filled vibration isolator for automobiles but also to a fluid-filled vibration isolator used for motorcycles, railway vehicles, and industrial vehicles.

10: engine mount (fluid-filled vibration isolator), 12: first mounting member, 14: second mounting member, 16: main rubber elastic body, 36: flexible membrane, 42, 90, 100: partition Member, 58: pressure receiving chamber, 60: equilibrium chamber, 62: orifice passage, 64, 92, 102, 110: movable rubber plate (movable plate), 70: open cell, 72: skin, 94: reinforcing member

Claims (5)

The first mounting member and the second mounting member are connected by the main rubber elastic body, and the partition member is supported by the second mounting member, and the wall portion is disposed on one side of the partition member. A pressure receiving chamber composed of a part of the main rubber elastic body is formed, and an equilibrium chamber composed 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 sealed in the pressure receiving chamber and the equilibrium chamber, and an orifice passage that communicates the pressure receiving chamber and the equilibrium chamber is formed.
The movable member is supported by the partition member so as to be capable of minute displacement in the thickness direction, and pressure on the pressure receiving chamber side is exerted on one surface of the movable plate, and pressure on the equilibrium chamber side is exerted on the other side. The movable plate is formed of a foam material and has a plurality of open cells that open on both sides in the thickness direction, and the plurality of continuous cells on the pressure receiving chamber side surface of the movable plate. The opening area (S) of the bubbles is set in a range of 40 mm ² ≦ S ≦ 1500 mm ² , and
The open cell is open on both surfaces in the thickness direction of the movable plate, and a skin covering the open of the open cell is formed on the outer peripheral surface of the movable plate. Shaker. The fluid-filled vibration isolator according to claim 1, wherein the movable plate is made of foam rubber. The fluid-filled vibration isolator according to claim 1 or 2 , wherein a reinforcing member is fixed to the movable plate. A method for manufacturing the fluid-filled vibration isolator according to any one of claims 1 to 3 ,
A manufacturing method of a fluid filled type vibration damping device, wherein the movable plate is obtained by cutting a columnar foamed member obtained by molding a foamed material in a predetermined thickness in the axial direction. A method for manufacturing the fluid-filled vibration isolator according to any one of claims 1 to 3 ,
A fluid-filled vibration proof is characterized in that the movable plate is compressed and deformed in an incompressible fluid to release air in the open cell, and then the movable plate is assembled and disposed in the incompressible fluid. Device manufacturing method.

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