JP5524664B2 - 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 vehicle body side, a second attachment attached to the vibration source 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. Cavitation is a liquid in which the main liquid chamber becomes excessively negative pressure (that is, the liquid pressure in the main liquid chamber is lower than a predetermined value) when a large vibration is input to the vibration isolator, and the enclosed liquid This is a phenomenon caused by the generation of a large number of bubbles by lowering the saturated vapor pressure. And the shock wave when the bubble generated in this way disappears becomes an abnormal sound and is transmitted to the outside.

  In order to prevent the occurrence of abnormal noise due to cavitation, for example, in Patent Document 1 below, a short-circuit path that short-circuits both liquid chambers is provided in a partition member that partitions the main liquid chamber and the sub-liquid chamber, and the short-circuit path is in a communicating state. The valve body that switches to the shut-off state is composed of a metal spring such as a leaf spring, so that when the main liquid chamber is in an excessively negative pressure state, the short circuit is opened to move from the sub liquid chamber to the main liquid chamber. Dispensing liquid is disclosed.

  In the following Patent Document 2, a bottomed cylindrical mounting bracket in which an air chamber sealed inside is formed is press-fitted into the outer periphery of a cylindrical bracket to which a vibration-proof base is fixed in a liquid tank. It is disclosed that the fluid pressure in the fluid chamber is increased through the internal pressure of the air chamber and the deformation of the diaphragm, which are increased as assembly and press-fitting of the mounting bracket proceed.

  Patent Document 3 listed below discloses that a pressure is provided in a cover member that forms a sealed air chamber, and that the air chamber is pressurized by filling the air chamber with the compressed air through the pressure hole. ing.

  On the other hand, in Patent Document 4 below, as a configuration for forming the air chamber in an airtight state instead of the cavitation countermeasure as described above, a bolt is penetrated and fixed by serration fitting to the hook-shaped mounting bracket, and the mounting is performed. A structure in which a partition member is caulked and fixed inside the metal fitting is disclosed.

JP 2007-107712 A Japanese Patent Laid-Open No. 08-170683 JP 2007-239758 A Utility Model Registration No. 2525878

  The configuration of Patent Document 1 requires an increase in the number of parts by incorporating a structure such as a metal spring and refinement of assembly accuracy, which increases costs. Further, the configuration of Patent Document 2 requires fitting dimensional accuracy between the fitting and the cylindrical fitting that are press-fitted to each other, resulting in an increase in cost. Moreover, in the structure of the said patent document 3, the dimensional accuracy of the pressurization hole for filling with compressed air and the plug member which closes this is required, and it leads to a cost increase.

  On the other hand, the above-mentioned Patent Document 4 is provided with a cover metal fitting as a partition member in order to ensure airtightness in the bolt portion that is serrated and fitted, and is not intended to prevent cavitation. Further, since the cover metal part is caulked and fixed integrally at the caulking part between the main body metal fitting and the mounting metal part, the thickness of the caulking part having a large diameter will be increased by that amount. Considering the interference with the peripheral members, there is a problem that the mounting space is increased.

  The present invention has been made in view of the above points, and is a liquid-filled type prevention that can suppress cavitation caused by sudden pressure fluctuations at the time of large amplitude input at low cost without accompanying an increase in mount space. An object is to provide a vibration device.

The liquid-filled vibration isolator according to the present invention includes a first fixture that is attached to either the vibration source side or the support side, a second fixture that is attached to either the vibration source side or the support side, An anti-vibration base made of a rubber-like elastic body interposed between the first fixture and the second fixture, a diaphragm made of a rubber-like elastic film supported on the second fixture side, and A main liquid chamber in which a liquid whose base is part of a chamber wall is sealed, a sub liquid chamber in which a liquid whose diaphragm is a part of the chamber wall is sealed, the main liquid chamber and the sub liquid chamber In the liquid-filled vibration isolator having an orifice flow path, the second fixture is sealed on the opposite side of the sub liquid chamber with the diaphragm sandwiched by covering the back of the diaphragm. A cap member that forms an air chamber is provided, and inside the cap member, The cap member is built small volume of members to reduce the volume of the air chamber be made of a small solid specific gravity than the small volume of members, the peripheral wall of the cap member having a bottomed cylindrical shape It is fitted and fixed to the inner peripheral surface of the part over the entire circumference, and a meat stealing recess is provided between the bottom surface of the cap member .

  According to the present invention, since the volume of the air chamber is reduced by incorporating the solid material in the cap member, the air chamber is compressed (volume fluctuation) by applying the weight of a vibration source such as an engine when mounted on the vehicle. Therefore, the pressure of the air chamber can be increased more efficiently because the volume of the original air chamber is small. As a result, the pressure value of the liquid in the liquid chamber can be increased through the deformation of the diaphragm, so that the occurrence of cavitation due to an excessive negative pressure state in the liquid chamber can be suppressed. Further, in this case, since the solid material is built in the cap member, it is not accompanied by an increase in mount space, is inexpensive, and uses a solid material having a specific gravity lower than that of the cap member. Cavitation resistance can be improved while suppressing an increase in weight.

1 is a longitudinal sectional view of a liquid-filled vibration isolator according to a first embodiment. Longitudinal sectional view of liquid filled vibration isolator according to reference example Longitudinal sectional view of a liquid filled type vibration isolator according to the second embodiment Sectional view taken along line IV-IV in FIG.

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

  FIG. 1 is a longitudinal sectional view of a liquid-filled vibration isolator 10 according to the first embodiment. The vibration isolator 10 is an engine mount that supports an automobile engine, and includes an upper first attachment 12 that is attached to an engine-side member that is a vibration source, and a cylinder that is attached to a vehicle-side member that is a support side. 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.

  The first fixture 12 is a boss fitting disposed above the axial center portion of the second fixture 14, and the axial direction X (that is, the vertical direction) of the second fixture 14 is the main load direction of the vibration isolator 10. It is connected to the second fixture 14 via the vibration isolation base 16 so as to be in the main load input direction. The first fixture 12 is formed with a stopper portion 18 projecting in a flange shape outward in the radial direction. Further, a female screw portion 20 is provided on the upper surface, and is configured to be attached to a member on the engine side by screwing a bolt (not shown) therein.

  The second fixture 14 includes a cylindrical tubular member 22 in which the vibration-proof base 16 is vulcanized and a bottomed cylindrical cap member 24 fastened to the lower end thereof, and is made of a rigid body such as metal. Is formed.

  The cylindrical member 22 includes an inversely tapered portion 26 that spreads outward at an upper end that is one end in the axial direction X, and the antivibration base 16 is coupled to the inversely tapered portion 26. A flange portion 28 projecting radially outward is provided at the upper end of the reverse tapered portion 26, and the lower end portion of the stopper fitting 30 that exerts a stopper action with the stopper portion 18 of the first fixture 12 is provided. The flange portion 28 is caulked and fastened. The lower end portion of the cylindrical member 22 is caulked and fastened to the upper end opening of the cap member 24 by a caulking portion 32. A stopper rubber 34 is covered on the upper surface of the stopper fitting 30.

  The anti-vibration base 16 is formed in a substantially umbrella shape, and is vulcanized and bonded in a state where the first fixture 12 is embedded in the upper part thereof, and the outer peripheral portion of the lower end is vulcanized and bonded to the reverse tapered portion 26 of the cylindrical member 22. Has been. A rubber film-like seal wall portion 36 covering the inner peripheral surface of the cylindrical member 22 is connected to the lower end portion of the vibration isolation base 16.

  A diaphragm 40 made of a flexible rubber film is disposed on the second fixture 14 so as to face the lower surface of the vibration isolating base 16 in the axial direction X and form a liquid sealing chamber 38 between the vibration isolating base 16. A liquid enclosure chamber 38 is filled with a liquid such as water, alkylene glycol, or silicone oil. The diaphragm 40 includes an annular reinforcing metal fitting 42 on the outer peripheral portion, and is fixed to the caulking portion 32 via the reinforcing metal fitting 42.

  The liquid enclosure chamber 38 is formed between the lower surface of the vibration isolation base 16 and the diaphragm 40 on the inner side of the second fixture 14, specifically, on the inner side of the cylindrical member 22. The main liquid chamber 38A is divided into an upper main liquid chamber 38A in which the anti-vibration base 16 forms a part of the chamber wall, and a lower sub liquid chamber 38B in which the diaphragm 40 forms a part of the chamber wall. It has been. The main liquid chamber 38 </ b> A and the sub liquid chamber 38 </ b> B are communicated with each other by an orifice channel 46 provided on the outer peripheral portion of the partition body 44.

  In this example, the partition body 40 is a pressed product of a metal plate. The partition body 40 is fitted inside the cylindrical member 22 via a seal wall portion 36, and the orifice is interposed between the seal wall portion 36. While forming the flow path 46, the outer periphery of a lower end is formed in the attachment flange 48 which spreads to radial direction outward. The mounting flange 48 is caulked and fixed by the caulking portion 32 of the tubular member 22 together with the reinforcing metal fitting 42 at the peripheral portion of the diaphragm 40.

  The cap member 24 is a member that forms an air chamber 50 that is sealed on the opposite side of the sub liquid chamber 38B across the diaphragm 40 by covering the back of the diaphragm 40, in this example, the lower surface side. That is, with the diaphragm 40 as a partition, the upper side is a liquid sealing chamber 38 and the lower side is an air chamber 50. The cap member 24 includes a flange portion 54 that is formed to project radially outward at an upper end portion, and the flange portion 54 is caulked and fastened by a caulking portion 32 at the lower end portion of the cylindrical member 22.

  The cap member 24 has a mounting bolt 52 projecting downward at the center of the bottom thereof, and is configured to be fastened to a member on the vehicle body via the mounting bolt 52. Thereby, the cap member 24 has a structure that receives an input (ie, an external force) in the main load direction of the vibration isolator 10. The mounting bolt 52 is a serration bolt having a serration 52B below the head 52A. The mounting bolt 52 is fixed to the bottom wall portion 56 of the cap member 24 by press-fitting, and the screw portion 52C protrudes downward.

  In the above configuration, in the present embodiment, the volume reducing member 58 for reducing the volume of the air chamber 50 is built in the cap member 24 forming the air chamber 50. The small volume member 58 is made of a solid material having a specific gravity smaller than that of the cap member 24, and is formed of a rubber elastic body in this example.

  The small volume reducing member 58 has a thick disk shape, and its outer peripheral portion 58A is fitted and fixed to the inner peripheral surface 60A of the peripheral wall portion 60 of the cap member 24 over its entire periphery, and its bottom surface is the cap member 24. By being in contact with the bottom wall portion 56 of the cap member 24, it is held so as to fill the bottom portion side of the cap member 24. An accommodation recess 62 in which the head 52 </ b> A of the mounting bolt 52 is accommodated is provided at the center of the small volume member 58. The housing recess 62 is provided on both the front and back surfaces of the small volume member 58 in order to prevent erroneous insertion when the small volume member 58 is loaded into the cap member 24. It is formed in the same shape with no direction on the front and back.

  By incorporating the small volume member 58 in this way, the volume of the air chamber 50 inside the cap member 24 is smaller than when the small volume member 58 is not provided. In this example, the volume is less than half. It has become. Therefore, the air chamber 50 can be efficiently increased in pressure due to the volume fluctuation of the air chamber 50 accompanying the application of the engine's own weight when mounted on the vehicle.

Specifically, the volume variation ΔV of the air chamber 50 due to the engine's own weight is defined as the effective piston area of the vibration isolating base 16 due to the downward displacement of the first fixture 12 and the downward deflection amount of the vibration isolating base 16 Assuming Δx, it is approximately equal to the product of both (ie, ΔV≈A · Δx). On the other hand, the relationship of the pressure P ′ after the application to the pressure P of the air in the air chamber 50 before the application of the engine's own weight is expressed as follows.
PV = P ′ (V−ΔV)
It is represented by Therefore, it is clear that the effect of increasing the pressure of the air chamber 50 when the same pressure fluctuation ΔV occurs increases as the original volume V decreases.

  Therefore, in the above embodiment, since the volume of the air chamber 50 is reduced by the incorporation of the volume reducing member 58, the air chamber 50 is compressed when the air chamber 50 is compressed (volume fluctuation) by the application of the engine's own weight. 50 can be increased in pressure more efficiently, whereby the liquid in the liquid enclosure chamber 38 can be increased to substantially the same pressure as the air chamber 50. Therefore, it is possible to suppress the occurrence of cavitation due to an excessive negative pressure state in the main liquid chamber 38A. Further, in this case, since the volume reducing member 58 is built in the cap member 24, the outer shape of the cap member 24 is not changed, so that the mounting space is not increased, and the cost is low. It is. In addition, since the solid member having a specific gravity lower than that of the cap member 24 is used as the volume reducing member 58, the cavitation resistance can be improved while suppressing an increase in weight. In addition, since the small volume member 58 is fixed to the inner surface of the cap member 24, it is possible to prevent noise due to rattling in the cap member 24.

  In order to suppress an increase in the weight of the vibration isolator 10, a solid having a specific gravity smaller than that of the cap member 24 is used as the solid constituting the volume reducing member 58. In addition to the rubber elastic body, for example, polypropylene or Examples thereof include resin molded articles such as polyamide, polyester and polyurethane, and foamed resin molded articles such as expanded polystyrene, polyethylene foam, polypropylene foam and polyurethane foam. As a foamed resin molding, what has a closed cell structure without air permeability is preferable. Among these, it is preferable to use a rubber-like elastic body made of various elastomers including rubber, and in terms of cost and weight reduction, a foamed resin molded body such as polystyrene foam or polypropylene foam is press-fitted into the cap member 24. It is preferable to wear it.

  Further, if the volume reducing member 58 is a member that deforms with the pressure fluctuation of the air chamber 50, the volume of the air chamber 50 cannot be reduced efficiently, and the above-described high pressure cannot be sufficiently achieved. It is preferable to select a shape and material having a deformation resistance (that is, difficult to be deformed) against pressure fluctuations in the air chamber 50. For example, when the small volume member 58 is formed of a rubber-like elastic body, it is preferable to use a thick solid material as described above.

  In order to reduce the volume of the air chamber 50, it is conceivable to reduce the height of the cap member 24 itself. However, in this type of vibration isolator, the cap member 24 is restricted due to restrictions on mounting on the vehicle. In some cases, it is necessary to secure a certain height from the fixed vehicle body side member to the large caulking portion 32, or from the relationship between the vehicle body side member and the elastic main shaft of the vibration isolator due to the movement of the engine. The height of the cap member 24 itself may be secured to some extent (also referred to as the elastic center of the vibration-isolating base, which is located near the lower end of the first fixture 12 in FIG. 1). The height may not be changed. In such a case, the anti-cavitation performance can be effectively enhanced by an inexpensive method of incorporating the small volume member 58 in the cap member 24 as in the present embodiment.

  In addition, when the height of the cap member 24 itself is lowered, there is a possibility that the diaphragm 40 is displaced downward at the time of large amplitude vibration and abuts against the bottom surface of the cap member 24 made of metal to generate a collision sound. By incorporating the volume-reducing member 58 made of a rubber-like elastic body as in this embodiment, even if the diaphragm 40 abuts, the rubber collides with each other, so there is also an advantage that the collision sound can be reduced. .

  When the volume reducing member 58 is made of a rubber-like elastic body, it can be easily fitted to the inner peripheral surface 60A of the cap member 24 by being press-fitted from the opening side of the cap member 24, and after the fitting. Can be held in the cap member 24 by the elastic force of the rubber-like elastic body, so that it is excellent in assembling workability and can easily prevent abnormal noise due to rattling of the small volume member 58 after assembly. .

FIG. 2 shows a liquid-filled vibration isolator 10A according to a reference example . In this example, the configuration of the small volume member 58 is different from that of the first embodiment.

  That is, in this example, the volume reducing member 58 is bonded and fixed to the inner side surface of the cap member 24 so as to wrap the head 52A of the mounting bolt 52. Specifically, the small volume member 58 has a cylindrical shape that covers the entire head 52A of the mounting bolt 52 fixed to the bottom wall portion 56 of the cap member 24, and the head 52A on the bottom surface 56A of the cap member 24. Vulcanized and bonded around the entire periphery.

  Thus, in the structure in which the mounting bolt 52 is press-fitted into the cap member 24, the volume of the air chamber 50 can be reduced by the volume reduction member 58 by bonding and fixing the volume reduction member 58 around the bolt head 52A. In addition, it is possible to ensure the airtightness of the air chamber 50, and it becomes unnecessary to apply the sealing material to the serration bolt which has been conventionally performed. Other configurations and operational effects are the same as those of the first embodiment, and a description thereof will be omitted.

3 and 4 show a liquid-filled vibration isolator 10B according to the second embodiment. In this example, the configuration of the small volume member 58 is different from that of the first embodiment.

  That is, in this example, the volume reducing member 58 is fitted and fixed to the inner peripheral surface 60A of the peripheral wall portion 60 of the cap member 24 over the entire periphery, and the meat stealing concave portion 64 is interposed between the bottom surface 56A of the cap member 24. Is provided.

  More specifically, the volume reducing member 58 has an outer peripheral portion 58A that is press-fitted into the inner peripheral surface 60A of the peripheral wall portion 60 of the cap member 24, so that the diaphragm 40 is located above the outer peripheral portion 58A. A sealed air chamber 50 is formed. On the lower surface side of the small volume member 58, a plurality of ribs 66 are provided for holding the small volume member 58 at a predetermined height in the cap member 24 by contacting the bottom surface 56A of the cap member 24. It has been. As shown in FIG. 4, the rib 66 includes an annular rib 66A that surrounds the head 52A of the mounting bolt 52, and a plurality of radial ribs 66B that extend radially from the annular rib 66A. Ribs 66B are provided. Further, four meat stealing recesses 64 are provided between the plurality of ribs 66, specifically, between the radial ribs 66 </ b> B, and a space portion is formed between the bottom wall portion 56 and the peripheral wall portion 60 of the cap member 24. Has been.

  In this way, after the small volume member 58 is fitted into the inner peripheral surface 60 </ b> A of the peripheral wall 60 of the cap member 24 in a sealed state, the small volume member 58 is stealed on the bottom side of the cap member 24. As a result, the weight can be reduced by reducing the amount of the volume-reducing member 58 made of a rubber-like elastic body while ensuring the effect of reducing the volume of the air chamber 50 compared to the first embodiment. Is possible. Other configurations and operational effects are the same as those of the first embodiment, and a description thereof will be omitted.

  In the above-described embodiment, the single-orifice structure vibration-proof device having a single orifice passage has been described. However, the present invention is a liquid-filled vibration-proof device that communicates a plurality of liquid chambers with an orifice passage. If present, the present invention can be applied to various liquid-filled vibration isolators such as a double orifice structure vibration isolator. 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.

10, 10A, 10B ... Liquid-sealed vibration isolator,
12 ... 1st fixture, 14 ... 2nd fixture, 16 ... Anti-vibration base | substrate,
22 ... cylindrical member, 24 ... cap member, 38A ... main liquid chamber,
38B ... Secondary liquid chamber, 40 ... Diaphragm, 46 ... Orifice flow path,
DESCRIPTION OF SYMBOLS 50 ... Air chamber, 52 ... Mounting bolt, 52A ... Head 56 ... Bottom wall part, 58 ... Small volume member, 60 ... Perimeter wall part 64 Meat stealing recessed part

Claims (2)

A first fixture attached to either the vibration source side or the support side; a second fixture attached to either the vibration source side or the support side; the first fixture and the second fixture; An anti-vibration base made of a rubber-like elastic body interposed between them, a diaphragm made of a rubber-like elastic film supported on the second fixture side, and a liquid in which the anti-vibration base forms a part of a chamber wall A liquid comprising: a main liquid chamber in which a liquid is sealed; a sub liquid chamber in which a liquid whose diaphragm forms a part of a chamber wall is sealed; and an orifice channel that communicates the main liquid chamber and the sub liquid chamber. In the enclosed vibration isolator,
The second fixture includes a cap member that covers the back of the diaphragm so as to form an air chamber that is sealed on the opposite side of the sub liquid chamber with the diaphragm interposed therebetween, and the cap member is provided inside the cap member. It is made of a solid material having a specific gravity smaller than that of the member, and a small volume reducing member for reducing the volume of the air chamber is incorporated , and the small volume reducing member has a bottomed cylindrical shape of the peripheral wall portion of the cap member A liquid-sealed vibration isolator characterized in that it is fitted and fixed to the inner peripheral surface over the entire periphery, and a meat stealing recess is provided between the inner peripheral surface and the bottom surface of the cap member . The liquid-filled vibration isolator according to claim 1 , wherein the volume reducing member is made of a rubber-like elastic body.

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