JP5702250B2 - Liquid-filled vibration isolator - Google Patents

Description

  The present invention relates to a liquid-filled vibration isolator.

  As an anti-vibration device such as an engine mount that supports the vibration of a vibration source such as an automobile engine so as not to be transmitted to the vehicle body side, a first attachment attached to the vibration source side, a second attachment attached to the support side, An anti-vibration base made of a rubber-like elastic body interposed between the fixtures, a main liquid chamber in which the anti-vibration base forms part of the chamber wall, and a sub-liquid chamber in which the diaphragm forms part of the chamber wall; A liquid-filled vibration isolator having an orifice channel for communicating between these liquid chambers is known.

  In such a liquid-filled vibration isolator, during normal vibration input, the vibration damping function and the vibration insulation function are performed by the liquid column resonance action due to the liquid flow in the orifice channel and the vibration damping effect of the vibration isolating substrate. When a large vibration is input, the vibration isolator itself may be an abnormal sound source and transmitted to the passenger compartment.

  This abnormal noise is generated by cavitation in the liquid chamber. In cavitation, when a large vibration is input to the vibration isolator, the orifice flow path is clogged, and thereby the main liquid chamber is in an excessively negative pressure state (that is, the liquid pressure in the main liquid chamber drops below a predetermined value). This is a phenomenon that occurs when a large number of bubbles are generated by lowering the saturated vapor pressure of the sealed liquid. And the impact sound when the bubble generated in this way disappears becomes an abnormal sound and is transmitted to the outside.

  Conventionally, in order to prevent the occurrence of abnormal noise and vibration due to cavitation, for example, in Patent Document 1 below, an annular intermediate plate is embedded in a diaphragm to increase the expansion spring constant at the time of large amplitude input. Is disclosed. Thus, by increasing the expansion spring constant of the diaphragm, it is possible to increase the pressure in the main liquid chamber and prevent it from being greatly reduced when the main liquid chamber is expanded immediately thereafter. Japanese Patent Application Laid-Open No. H10-228561 discloses that the facing surface with which the diaphragm abuts is formed as a stopper with a metal fitting, thereby increasing the expansion spring constant of the diaphragm after the stopper abutment upon large amplitude input. However, in the configuration of Patent Document 2, abnormal noise may occur due to the contact between the diaphragm and the stopper.

  On the other hand, in Patent Document 3 below, in order to prevent cavitation, the pressure of the air chamber can be increased by press-fitting and fitting a cover member that forms an air chamber with the diaphragm into the main body fitting. A structure is disclosed in which a cylindrical projection is provided from a diaphragm in order to seal a press-fit portion. However, the cylindrical projection is formed on the outer peripheral portion of the diaphragm so as to protrude along the inner peripheral surface of the cover member, and a cylindrical metal fitting is embedded, and is outside the range of the flexible portion of the diaphragm. It does not suppress the bending deformation of the diaphragm.

  Further, Patent Document 4 below discloses a configuration in which a cylindrical rubber extending portion protrudes from the lower surface periphery of the diaphragm. However, this rubber extending portion is provided as a dust cover for the vehicle body member below the engine mount, and is provided outside the range of the flexible portion of the diaphragm so as to suppress the bending deformation of the diaphragm. Absent.

JP 2009-133379 A JP 2008-002629 A Japanese Patent Laid-Open No. 08-170683 JP 2002-081488 A

  The present invention has been made in view of the above points, and is a liquid-filled vibration isolator capable of suppressing cavitation caused by a rapid pressure fluctuation at the time of large amplitude input and having an excellent noise reduction effect. The purpose is to provide.

 The liquid-filled type vibration isolator according to the present invention includes a first attachment attached to either the vibration source side or the support side, and a cylindrical second attachment attached to either the vibration source side or the support side. A vibration isolating base made of a rubber-like elastic body interposed between the first fixture and the second fixture, and the anti-vibration base attached to the second fixture side. A diaphragm made of a rubber-like elastic body that forms a liquid sealing chamber, a partition that partitions the liquid sealing chamber into a main liquid chamber on the vibration-proof base side and a sub liquid chamber on the diaphragm side, and the main liquid chamber In a liquid-filled vibration isolator having an orifice communicating with the secondary liquid chamber, the second fixture covers the back of the diaphragm so that the air is placed on the opposite side of the secondary liquid chamber with the diaphragm interposed therebetween. A cover member forming a chamber, in front of the diaphragm A cylindrical projection made of a rubber-like elastic body for suppressing bending deformation toward the air chamber is formed so as to protrude from one of the opposing surfaces of the diaphragm and the cover member within the flexible portion of the diaphragm. It has been done.

  As a preferred aspect of the present invention, the cylindrical protrusion is provided concentrically with respect to the axis of the flexible part, and at least 1 within a range of 50% of the diameter of the flexible part with the axis as the center. One may be provided. As another preferred embodiment, the cylindrical protrusion may be formed so as to protrude from a film surface on the air chamber side of the diaphragm. In this case, the bottom wall of the cover member is fixed with a bolt that protrudes outward with the head in the air chamber, and at the time of large amplitude input, at least a part of the tip of the cylindrical protrusion is The said cylindrical protrusion may be provided so that it may contact | abut to a head. As another preferred embodiment, a slit may be provided at the tip of the cylindrical protrusion. As another preferred embodiment, a plurality of the cylindrical protrusions may be provided concentrically with respect to the axis of the flexible portion. In addition, these preferable each aspects can be combined suitably.

  By providing the cylindrical protrusion made of a rubber-like elastic body as described above, when the diaphragm is greatly bent toward the air chamber side when a large amplitude is input, the tip of the cylindrical protrusion abuts against the cover member or the diaphragm. By contact, bending deformation of the diaphragm is suppressed, and the expansion spring constant of the diaphragm is increased. As a result, the liquid pressure in the main liquid chamber can be increased, so that an excessive negative pressure state in the main liquid chamber can be suppressed when a load in the direction in which the liquid pressure in the main liquid chamber decreases continues to be input. Thus, the occurrence of cavitation can be suppressed. In addition, when such a cylindrical projection is used, the cylindrical projection is elastically deformed in the axial direction even when abnormal noise is generated when the tip of the cylindrical projection abuts against a cover member or a diaphragm. Can absorb the energy at the time of contact, and can suppress the generation of abnormal noise.

It is a longitudinal cross-sectional view of the liquid filled type vibration isolator which concerns on embodiment. It is a bottom view of the diaphragm in the embodiment. It is the III-III sectional view taken on the line of FIG. It is the IV-IV sectional view taken on the line of FIG. It is a principal part expansion longitudinal cross-sectional view at the time of the large amplitude input of the liquid enclosure type vibration isolator.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  A liquid-filled vibration isolator 10 according to the present embodiment shown in FIG. 1 is an engine mount that supports an engine of an automobile, and an upper first fixture 12 that is attached to an engine side that is a vibration source, and a support. And a vibration-proof base 16 made of a rubber elastic body that is interposed between the two attachments 12 and 14 and connects them. It becomes. FIG. 1 shows a no-load state.

  The first fixture 12 is a metal fitting disposed above the shaft core portion of the second fixture 14. In this example, the first fixture 12 has a flat plate shape, and a bolt 18 is fixed upward. It is configured to be attached to the engine side. A stopper fitting 20 is fixed on the upper surface of the first fixture 12.

  The second fixture 14 includes a cylindrical tubular member 22 in which the vibration-proof base 16 is vulcanized and a bottomed cylindrical cover member 24 fastened to the lower end portion thereof, and is made of a rigid body such as metal. Is formed. A bolt 26 projects downward from the bottom wall 24 </ b> A of the cover member 24, and the second fixture 14 is configured to be attached to the vehicle body via the bolt 26. The cylindrical member 22 is caulked and fixed to the upper end opening of the cover member 24 by a caulking portion 28 at the lower end thereof. Reference numeral 30 denotes a stopper portion that exerts a stopper action with the stopper fitting 20. Note that the cylindrical member 22 and the cover member 24 may be formed of an integral metal fitting.

  The anti-vibration base body 16 is formed in a substantially umbrella shape, the first fixture 12 is vulcanized and bonded to the upper end portion thereof, and the outer peripheral portion of the lower end is vulcanized and bonded to the upper end opening portion of the cylindrical member 22. A rubber film-like seal wall portion 32 that covers the inner peripheral surface of the cylindrical member 22 is connected to the lower end portion of the vibration isolation base 16.

  A diaphragm 36 made of a flexible rubber film is disposed on the second fixture 14 so as to be opposed to the lower surface of the vibration isolating base 16 in the axial direction X and form a liquid sealing chamber 34 with the vibration isolating base 16. A liquid is enclosed in the liquid enclosure chamber 34.

  The diaphragm 36 includes an annular reinforcing member 38 on the outer peripheral portion, and is fixed to the caulking portion 28 via the reinforcing member 38. The reinforcing member 38 is a hollow disc-shaped metal fitting, and a flexible portion 40 that can be bent and deformed in the axial direction X is formed in a film shape by a rubber elastic body so as to close the hollow portion. The flexible portion 40 has a circular shape in plan view as shown in FIG. 2, and as shown in FIG. 3, a curved surface that swells upward, that is, toward the vibration-isolating base 16 side, with the central portion 40A as a top portion. It has a shape. Specifically, after the outer peripheral portion 40B bulges downwardly, that is, toward the cover member 24 side, the inner side bulges upward in a curved surface shape, thereby forming a dome shape with the central portion 40A as the top. Is formed. Here, the flexible part 40 is a part which consists only of a rubber elastic body inside the reinforcing member 38 which is a rigid body.

  The liquid sealing chamber 34 is formed between the lower surface of the vibration-isolating base 16 and the upper surface of the diaphragm 36 inside the second fixture 14 (specifically, the cylindrical member 22), and includes water, ethylene glycol, Liquid such as silicone oil is enclosed. The liquid sealing chamber 34 is divided by the partition 42 into the main liquid chamber 34A on the vibration isolating base 16 side, that is, the upper main liquid chamber 34 where the vibration isolating base 16 forms a part of the chamber wall, and the diaphragm 36 side, that is, the diaphragm 36 on the chamber wall. And is divided into a lower secondary liquid chamber 34B.

  In this example, the partition body 42 is formed into a disk shape by pressing a metal plate, and a flange portion 44 is formed so as to project outward from the peripheral edge of the lower end thereof. The partition body 42 is fitted to the second fixture 14 by caulking and fixing the flange portion 44 together with the reinforcing member 38 of the diaphragm 36 by the caulking portion 28. The partition 42 has a central portion of the outer peripheral surface that is recessed inward, and an orifice 46 that communicates between the main liquid chamber 34A and the sub liquid chamber 34B is provided between the outer peripheral surface and the seal wall portion 32. Is formed.

  The orifice 46 is a liquid flow path provided along the circumferential direction in the outer peripheral portion of the partition body 42, and one end in the circumferential direction communicates with the main liquid chamber 34 </ b> A side via the first opening 46 </ b> A, and the other end It communicates with the secondary liquid chamber 34B through the second opening 46B (see FIG. 1). In this example, the orifice flow path 46 is a shake orifice tuned to a low frequency range (for example, about 5 to 15 Hz) corresponding to the shake vibration in order to attenuate the shake vibration during vehicle travel. That is, tuning is performed by adjusting the cross-sectional area and length of the flow path so that the damping effect based on the resonance action of the liquid flowing through the orifice flow path 46 is effectively exhibited when the shake vibration is input.

  The cover member 24 is a cap fitting that covers the rear side of the diaphragm 36, in this example, the lower surface side, and forms an air chamber 48 that is sealed on the opposite side of the sub liquid chamber 34B across the diaphragm 36. That is, with the diaphragm 36 as a partition, the upper side is a liquid sealing chamber 34, and the inner side of the lower cover member 24 is an air chamber 48. The air chamber 48 may be provided in communication with the outside air.

  The cover member 24 has a flange portion 24 </ b> B projecting radially outward at the upper end portion, and the flange portion 24 </ b> B is caulked and fastened by a caulking portion 28 at the lower end portion of the cylindrical member 22. As described above, the cover member 24 includes the bolt 26 that protrudes downward from the center of the bottom wall 24A. The bolt 26 is a serration bolt having a serration 26B below the disk-shaped head portion 26A, and is fixed by being penetrated into the bottom wall 24A of the cover member 24. The head portion 26A is disposed in the air chamber 48, The screw part 52C is provided in a state of protruding outward (downward in this example).

  As shown in FIG. 1, the diaphragm 36 is integrally provided with a cylindrical protrusion 50 made of a rubber elastic body protruding into the air chamber 48. The cylindrical protrusion 50 suppresses bending deformation of the diaphragm 36 toward the air chamber 48 when a large amplitude is input, and the air chamber 48 of the flexible portion 40 is within the range of the flexible portion 40 of the diaphragm 36. It protrudes downward from the film surface on the side, that is, toward the cover member 24 side. The cylindrical protrusion 50 is a thin cylindrical protrusion provided concentrically with the axis (center) O (see FIG. 3) of the flexible portion 40, and protrudes in the axial direction X. Further, in a normal use state including an initial load, the protrusion (not lower end) of the cylindrical protrusion 50 is formed at a protruding height that does not reach the bottom wall 24 </ b> A of the cover member 24 so as not to contact the cover member 24. ing.

  The cylindrical protrusion 50 abuts against the cover member 24 when a large amplitude is input, thereby suppressing excessive deformation of the diaphragm 36 toward the air chamber 48 and increasing its expansion spring constant. Is formed as a cylindrical protrusion extending in the axial direction X. Specifically, as shown in FIG. 3, the cylindrical protrusion 50 has a protruding height Q from the film surface that is larger than the thickness (average thickness in the axial direction X) P (Q> P). Is set to Thereby, even after the contact with the cover member 24 at the time of large amplitude input, the elastic deformation in the axial direction X of the cylindrical protrusion 50 is allowed, and the transmission energy to the cover member 24 can be relaxed. More preferably, it is formed in a thin cylindrical shape such that the protrusion height Q is three times or more the thickness P (Q ≧ 3P), and the effect of reducing the impact can be enhanced. In addition, the cylindrical protrusion 50 preferably has an inclination angle (angle with respect to the axial direction X) θ from 0 ° ≦ θ ≦ 30 ° from the tip of the both side surfaces to the root.

  A plurality of cylindrical protrusions 50 are provided concentrically with respect to the axial center O of the flexible portion 40. In this example, the cylindrical protrusions 50 are provided in a double circle shape with an inner cylindrical protrusion 50A and an outer cylindrical protrusion 50B. (See FIG. 2). It is preferable that at least one cylindrical protrusion 50 is provided within a range of 50% of the diameter of the flexible portion 40 with the axis O as the center. That is, at least one cylindrical protrusion 50 is disposed within a range of D / 2 with the axis O as the center when the diameter of the flexible portion 40 is D (see FIG. 3). As an example, in the illustrated example, the inner cylindrical projection 50A has a diameter of about 0.2D and the outer cylindrical projection 50B has a diameter of about 0.5D. Therefore, the inner cylindrical projection 50A and the outer cylindrical projection 50B A total of two cylindrical protrusions 50 are arranged within the range of D / 2.

  About the relationship of the protrusion height Q of 50 A of inner side cylindrical protrusions, and the outer side cylindrical protrusion 50B, you may set to the same height and you may set either high. In general, the flexible portion 40 of the diaphragm 36 has the largest amount of bending deformation at the central portion 40A, and the amount of bending deformation decreases toward the outer peripheral side. Therefore, the outer cylindrical protrusion 50B also comes into contact with the cover member 24. In order to effectively exhibit the bending suppression effect, it is often preferable to set the outer cylindrical protrusion 50B to have a higher protrusion height than the inner cylindrical protrusion 50A. As an example, in the illustrated example, the inner cylindrical protrusion 50A has a protruding height Q = about 8 mm, a thickness P = 1 mm, and an inclination angle θ = 2 °, and the outer cylindrical protrusion 50B has a protruding height Q = About 10 mm, thickness P = 1 mm, and inclination angle θ = 2 °.

  The inner cylindrical protrusion 50A is set so that the tip of the inner cylindrical protrusion 50A contacts the head 26A of the bolt 26 when a large amplitude is input (see FIG. 5). That is, the inner cylindrical protrusion 50A is provided at a position overlapping the head portion 26A when viewed from the axial direction X. In this example, the disk-shaped head portion 26A is provided so as to have a common axis O with the flexible portion 40. Therefore, the inner cylindrical protrusion 50A also has a common axis O. The diameter of the head portion 26A is set to be larger than the diameter of the inner cylindrical protrusion 50A, and therefore, the entire inner cylindrical protrusion 50A is set to abut against the head portion 26A. On the other hand, the outer cylindrical protrusion 50B is set to contact the bottom wall 24A of the cover member 24 around the head 26A.

  As shown in FIGS. 2 and 3, a slit 52 is provided at the tip of the cylindrical protrusion 50. That is, the cylindrical protrusion 50 is provided with a slit 52 having a constant width extending in the axial direction X from the tip (the lower end in this example). In this example, the slit 52 is provided at one place in the circumferential direction with respect to each of the cylindrical protrusions 50A and 50B. Further, the slit 52 has a depth in the axial direction X so that the slit 52 is not crushed and closed even when the cylindrical protrusion 50 is compressed and deformed in the axial direction X between the cover member 24 and the large amplitude input. Is set, and the depth of the slit 52 is set larger in the inner cylindrical protrusion 50A having a larger amount of compressive deformation than in the outer cylindrical protrusion 50B. As an example, in the illustrated example, the depth of the slit 52 of the inner cylindrical protrusion 50A is 5 mm, the depth of the slit 52 of the outer cylindrical protrusion 50B is 3 mm, and both slit widths are 2 mm.

  The cylindrical protrusion 50 is further provided with a reinforcing rib 54 for reinforcing the cylindrical protrusion 50 at the base portion thereof. As shown in FIGS. 2 and 4, the reinforcing ribs 54 reinforce the base portions of the cylindrical protrusions 50A and 50B from the inner peripheral side, and are evenly arranged at a plurality of locations in the circumferential direction (three locations in this example). Has been. Specifically, the reinforcing rib 54 has a triangular cross section as shown in FIG. 4, and connects the membrane surface of the diaphragm 36 main body inside the cylindrical protrusion 50 and the inner peripheral surface of the cylindrical protrusion 50. Is formed.

  In the liquid filled type vibration isolator 10 having the above-described configuration, the cylindrical protrusion 50 abuts on the cover member 24 at the time of vibration input with a frequency less than a predetermined amplitude that is a normal use region, for example, shake vibration with an amplitude of about 0.5 mm. Therefore, the expansion spring constant of the diaphragm 36 is small, so that the original damping performance due to the liquid flow effect at the orifice 46 can be exhibited.

  On the other hand, when the amplitude (relative displacement between the first fixture 12 and the second fixture 14) is larger than a predetermined amplitude such that the amplitude exceeds 1 mm (for example, when the vehicle travels on a rough road surface, the amplitude is 2 mm). When the diaphragm 36 is greatly bent toward the air chamber 48 due to the relative displacement of the first fixture 12 at the time of the vibration input of the degree), as shown in FIG. Abutting against the bottom wall 24A of the cover member 24, the bending deformation of the diaphragm 36 is suppressed, and the expansion spring constant of the diaphragm 36 is increased. As a result, since the pressure in the liquid enclosure chamber 34 can be increased, after that, when there is an input on the tension side where the first fixture 12 is relatively displaced upward and the hydraulic pressure in the main liquid chamber 34A is lowered, It is possible to suppress the liquid pressure in the main liquid chamber 34A from becoming an excessively negative pressure state, and it is possible to suppress the generation of abnormal noise due to cavitation.

  In addition, when the cylindrical protrusion 50 is used, the abnormal noise generated when it collides with the cover member 24 is also elastically deformed in the axial direction X to absorb the energy at the time of collision and transfer the energy to the cover member 24 Can be relaxed. That is, the transmission energy E to the cover member 24 is expressed by E = E1-E2 where E1 is the kinetic energy of the cylindrical protrusion 50, and E2 is the energy consumed by the deformation of the cylindrical protrusion 50. The energy transmitted to the cover member 24 can be reduced by the amount of energy consumed by the deformation of 50, and the generation of abnormal noise can be suppressed. In addition, since the cylindrical protrusion 50 is thin-walled, the load change due to the collision with the cover member 24 becomes smooth, and the shock feeling due to the collision can be reduced. For these reasons, it is possible to effectively reduce abnormal noise caused by the collision between the cylindrical protrusion 50 and the cover member 24.

  According to the present embodiment, the cylindrical protrusion 50 is provided closer to the central portion within 50% of the diameter D of the flexible portion 40. Since the diaphragm 36 has a larger amount of bending deformation at the central portion 40A, the bending suppression effect can be further enhanced by providing the cylindrical protrusion 50 closer to the central portion. In addition, as described above, the diaphragm 36 has a convex curved surface on the side of the vibration isolating substrate 16 with the central portion 40A as the top, so that the protruding height Q of the cylindrical protrusion 50 is increased toward the central portion. Thus, a large displacement stroke in the axial direction X of the cylindrical protrusion 50 can be ensured, and the energy absorption capability at the time of the collision can be enhanced.

  In addition, according to the present embodiment, since a plurality of cylindrical protrusions 50 are provided concentrically, the nonlinear spring characteristics of the diaphragm 36 can be adjusted stepwise when the large amplitude is input as described above. And since the energy absorption capability at the time of the said collision can further be raised, generation | occurrence | production of abnormal noise can further be suppressed.

  In addition, according to the present embodiment, since the cylindrical protrusion 50 is integrally formed with the diaphragm 36, the bending deformation of the diaphragm 36 can be suppressed at a low cost. At that time, the cylindrical protrusion 50A is brought into contact with the head 26A of the bolt 26 provided on the cover member 24 when the diaphragm 36 is deformed, so that the diaphragm main body makes contact with the head 26A. Thus, the risk of damage to the diaphragm 36 can be reduced.

  Further, according to the present embodiment, the slit 52 is provided in the cylindrical protrusion 50, so that the cylindrical protrusion 50 sticks to the wall surface of the cover member 24 after contact with the cover member 24, and the diaphragm 36 can be restored. It can be avoided.

  In addition, by providing the reinforcing rib 54 at the base of the cylindrical protrusion 50, deformation due to looseness of the cylindrical protrusion 50 due to repeated input of large amplitude vibration can be suppressed, and a stable function can be exhibited. it can.

  In addition, in the said embodiment, although the cylindrical protrusion 50 was provided in the inner and outer double, the number of the cylindrical protrusion 50 is not limited to this, You may provide one or three or more.

  In the above embodiment, the cylindrical protrusion 50 is provided integrally with the diaphragm 36, but protrudes from one of the opposing surfaces of the diaphragm 36 and the cover member 24 within the range of the flexible portion 40 of the diaphragm 36. If it is a thing, it is not limited to the said embodiment. That is, a similar cylindrical protrusion may be formed to protrude from the bottom wall 24 </ b> A of the cover member 24 as long as it is within a range facing the flexible portion 40 in the axial direction X. In this case, the cylindrical protrusion protrudes from the bottom wall 24A of the cover member 24 upward, that is, toward the diaphragm 36, and the tip end (upper end) contacts the diaphragm 36 in a normal use state including the initial load. In order to avoid this, it is formed at a protruding height that does not reach the lower surface of the diaphragm 36. When the large amplitude is input, the diaphragm 36 is brought into contact with the lower surface of the diaphragm 36, thereby suppressing excessive bending deformation of the diaphragm 36 toward the air chamber 48 and increasing the expansion spring constant. In this case, when the cylindrical protrusion is formed so as to protrude from the cover member 24 side, the cylindrical protrusion may be integrally vulcanized with the bottom wall 24A of the cover member 24, or may be separately vulcanized and molded. May be fixed to the bottom wall 24 </ b> A of the cover member 24.

  In the above embodiment, when the large amplitude is input, the tip of the inner cylindrical projection 50A is configured to abut against the head portion 26A of the bolt 26 as a whole, but the entire cylindrical projection is not necessarily in contact with the bolt head. It is not necessary to be provided as such. For example, when two bolts are provided on the bottom wall of the cover member, the bolt does not have a common axial center with the cylindrical protrusion, and therefore the cylindrical protrusion is provided eccentrically with respect to the bolt head. In such a case, even if the cylindrical protrusion is provided so as to cover a part of the bolt head, the cylindrical protrusion avoids contacting the bolt head by contacting the bolt head. Therefore, the possibility of damaging the diaphragm can be reduced.

  In the above embodiment, the case where the liquid chamber includes the main liquid chamber 34A and the single sub liquid chamber 34B has been described. However, the liquid chamber has a plurality of sub liquid chambers together with the main liquid chamber, and an orifice channel is provided between these liquid chambers. The present invention can be similarly applied to various liquid-filled vibration isolators connected via the. In addition, the liquid-filled vibration isolator 10 may be installed upside down by being turned upside down. Although not enumerated one by one, various modifications can be made without departing from the spirit of the present invention.

  The present invention can be used for various vibration isolators such as a mount that supports other power units such as a motor, a body mount, and a differential mount, in addition to an engine mount.

DESCRIPTION OF SYMBOLS 10 ... Liquid enclosure type vibration isolator 12 ... 1st fixture 14 ... 2nd fixture 16 ... Vibration isolator base 24 ... Cover member 26 ... Bolt 26A ... Head 34 ... Liquid enclosure chamber 34A ... Main liquid chamber 34B ... Secondary liquid Chamber 36 ... Diaphragm 40 ... Flexible portion 42 ... Partition 46 ... Orifice 48 ... Air chamber 50 ... Cylindrical projection 50A ... Inner cylindrical projection 50B ... Outer cylindrical projection 52 ... Slit X ... Axial direction O ... Flexible portion Axle D ... Diameter of flexible part

Claims (6)

A first fixture that is attached to either the vibration source side or the support side, a cylindrical second fixture that is attached to either the vibration source side or the support side, the first fixture, and the second An anti-vibration base made of a rubber-like elastic body interposed between the attachment and a rubber-like elastic body attached to the second attachment side to form a liquid sealed chamber between the anti-vibration base A diaphragm for partitioning the liquid sealing chamber into a main liquid chamber on the vibration isolation base and a sub liquid chamber on the diaphragm side, and an orifice for communicating the main liquid chamber and the sub liquid chamber. In a liquid-filled vibration isolator,
The second fixture includes a cover member that forms an air chamber on the opposite side of the sub liquid chamber across the diaphragm by covering the back of the diaphragm,
The cylindrical projection made of a rubber-like elastic body for suppressing the deformation of the diaphragm toward the air chamber side is any one of the facing surfaces of the diaphragm and the cover member within the flexible portion of the diaphragm. A liquid-filled vibration isolator characterized by being protruded from one side.   The cylindrical protrusion is provided concentrically with respect to the axis of the flexible part, and at least one of the cylindrical protrusions is provided within a range of 50% of the diameter of the flexible part with the axis as a center. The liquid-filled vibration isolator according to claim 1.   The liquid-filled vibration isolator according to claim 1 or 2, wherein the cylindrical protrusion is formed so as to protrude from a film surface on the air chamber side of the diaphragm.   The liquid-filled vibration isolator according to claim 1, wherein a slit is provided at a tip of the cylindrical protrusion.   The liquid-filled vibration isolator according to claim 1, wherein a plurality of the cylindrical protrusions are provided concentrically with respect to the axis of the flexible portion.   The bottom wall of the cover member is fixedly provided with a bolt that protrudes outwardly with a head in the air chamber, and at least a part of the tip of the cylindrical protrusion on the head when a large amplitude is input. The liquid-filled vibration isolator according to claim 3, wherein the cylindrical protrusion is provided so as to abut.

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