JP2004360836A - Liquid filled mount - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid filled mount capable of reducing the radiation of noise caused by the cavitation in the operating fluid. <P>SOLUTION: An elastic member 3 is connected between a first cylindrical mounting member 1 connected with a car body frame side, and a second mounting member 2 mounted in the inner periphery of the first mounting member and connected with an engine-side bracket 24, a diaphragm mounted at an upper part of the elastic member 3 is mounted on the first mounting member 1 in a sealed state, a liquid filled space between the elastic member 3 and the diaphragm 4 is separated into a lower liquid chamber A and an upper liquid chamber B by a partition 5, an orifice C communicating the lower liquid chamber A and the upper liquid chamber B is formed on the partition 5, and a cover 6 surrounding an outer side of the diaphragm 4 is constituted by holding an elastic layer 61 by metallic plates 62, 63 from both sides in the thickness direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention belongs to the anti-vibration technology, and is used as anti-vibration support means for, for example, an engine of an automobile, and is a liquid encapsulation that buffers and reduces vibration by deformation of an elastic body and movement of a working liquid accompanying the deformation. Regarding the expression mount.
[0002]
[Prior art]
Conventionally, as an engine mount that supports a power unit including an engine and a transmission in a vehicle in a vibration-proof manner, a liquid-filled mount that absorbs and reduces vibration by deformation of an elastic body and movement of a working liquid accompanying the elastic body has been known. As this type of liquid-encapsulated mount, a suspension-type mount disclosed in, for example, Japanese Patent Application Laid-Open Publication No. H11-216131 has been conventionally known.
[0003]
[Patent Document 1]
JP-A-7-269633 (FIG. 1)
[0004]
That is, in the conventional liquid-filled mount disclosed in Patent Document 1, the outer cylindrical first mounting member and the inner second mounting member are formed of a conical elastic body made of a rubber-like elastic material. It has a linked structure. A lower liquid chamber and an upper liquid chamber are defined by the partition wall between the elastic body and the diaphragm provided above the elastic body, and both liquid chambers communicate with each other via an orifice formed in the partition wall. ing. Further, a cover for protecting the diaphragm is attached to the upper end of the first attachment member.
[0005]
In this liquid-filled mount, the first mounting member is connected to the vehicle body side and the second mounting member is connected to the power unit side including the vehicle-mounted engine, and the weight of the power unit is elastically suspended by an elastic body. Then, when the elastic body is deformed due to the vertical relative displacement of the first mounting member and the second mounting member due to the vertical vibration, the working fluid repeatedly flows through the orifice due to the volume change of the upper and lower liquid chambers, The effect of insulating and damping the vertical vibration is obtained.
[0006]
[Problems to be solved by the invention]
In this type of liquid-filled mount, cavitation may be generated in the hydraulic fluid when a large-amplitude impact is input due to a bounce or the like at the time of stepping on or off a road surface step portion while the vehicle is running. This cavitation is caused by a sudden upward displacement of the first mounting member on the vehicle body side due to an impact input or a sudden downward displacement of the second mounting member on the power unit side, whereby the liquid pressure in the lower liquid chamber is instantaneously reduced to the saturated vapor pressure or less. This is a phenomenon in which air bubbles are generated in the hydraulic fluid by lowering, and immediately thereafter, the air bubbles disappear due to an increase in the fluid pressure. With the generation and disappearance of the air bubbles, abnormal noise is generated in the hydraulic fluid. According to the above-described liquid-filled mount according to the related art, the sound generated in the working fluid by cavitation vibrates the cover that protects the diaphragm, and propagates as harsh noise to the outside. There was a problem.
[0007]
The present invention has been made in view of the above-described problems, and a technical problem thereof is to provide a liquid-filled mount that reduces radiation of noise due to cavitation in a hydraulic fluid.
[0008]
[Means for Solving the Problems]
As a means for effectively solving the above-described technical problem, the liquid-filled mount according to claim 1 is a cylindrical first mounting member connected to the support body side, and is disposed on the inner periphery thereof to be supported. A second attachment member connected to the vibrating body side, an elastic body joined between the first attachment member and the second attachment member, and a diaphragm above and having an outer peripheral edge sealed to the first attachment member And a partition formed with an orifice formed to separate the liquid sealing space between the elastic body and the diaphragm into a lower liquid chamber on the elastic body side and an upper liquid chamber on the diaphragm side and to communicate the lower liquid chamber and the upper liquid chamber. And a cover surrounding the outside of the diaphragm, wherein the cover has a structure in which an elastic layer is sandwiched between metal plates from both sides in the thickness direction. According to this configuration, the vibration of the cover can be suppressed by the damping characteristics of the elastic layer.
[0009]
Further, as another means for effectively solving the above-mentioned technical problem, a liquid-filled mount according to claim 2 is provided with a cylindrical first mounting member connected to the support body side and an inner peripheral portion thereof. A second mounting member connected to the supported vibrating body side, an elastic body joined between the first mounting member and the second mounting member, and an outer peripheral edge above the first mounting member being sealed to the first mounting member. The attached diaphragm, the liquid sealing space between the elastic body and the diaphragm is separated into a lower liquid chamber on the elastic body side and an upper liquid chamber on the diaphragm side, and an orifice communicating the lower liquid chamber and the upper liquid chamber is provided. A formed partition and a cover surrounding the outside of the diaphragm are provided, and a spring-mass system including a shield plate and an elastic connecting body connecting the shield plate to the cover is provided inside or outside the cover, Spring-mass system It is obtained by set lower than the frequency range of noise that generates vibration frequency in the liquid. According to this configuration, when the spring-mass system is provided inside the cover, air propagation of abnormal noise generated in the hydraulic fluid to the cover is shielded by the shielding plate, and the spring-mass system is formed. When provided outside the cover, radiation of sound waves from the cover to the outside is shielded.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a liquid-filled mount according to the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a liquid-filled mount according to a first embodiment, and FIG. 2 is a longitudinal sectional view showing a cover of the liquid-filled mount of FIG.
[0011]
The liquid-filled mount according to the embodiment of FIG. 1 has a first mounting member 1, a second mounting member 2 arranged on the inner periphery thereof, and a joint between the first mounting member 1 and the second mounting member 2. The elastic body 3, the diaphragm 4 above the outer periphery 4 a of which the outer peripheral edge 4 a is sealed to the first mounting member 1, and the liquid sealing space between the elastic body 3 and the diaphragm 4 are connected to the lower liquid chamber A on the elastic body 3 side. And an upper liquid chamber B on the side of the diaphragm 4 and a partition wall 5 having an orifice C communicating the lower liquid chamber A and the upper liquid chamber B, and a cover 6 surrounding the outside of the diaphragm 4.
[0012]
The first mounting member 1 has a cylindrical shape, and has a cylindrical metal case 11 and a metal outer press-fitted to the outer peripheral surface of a small-diameter portion 11a stepped at the lower end thereof. And a ring 12. The first mounting member 1 is connected to a vehicle body frame side corresponding to the support body side according to claim 1 or 2 by a bolt (not shown) at a mounting arm 12a formed integrally with the outer ring 12. You.
[0013]
The second mounting member 2 is integrally connected to a metal cup-shaped flange 21 arranged on the inner periphery of the first mounting member 1 by welding or the like on the bottom lower surface thereof, and the lower end of the second mounting member 2 is formed outside the first mounting member 1. And a metal inner cylinder 22 extending below the ring 12. The second mounting member 2 is attached to an engine-side bracket 24 corresponding to the supported vibrator according to claim 1 or 2 via a bolt 23 screwed into a female screw hole on the inner periphery of the inner cylinder 22. Be tied.
[0014]
The elastic body 3 is made of a rubber-like elastic material, and extends from the outer periphery of the conical side wall 21 a of the cup-shaped flange 21 of the second mounting member 2 that opens upward to form the first mounting member 1. The case 11 has a substantially conical shape extending obliquely downward toward the lower inner peripheral surface of the case 11. Since the elastic body 3 is a main body that elastically supports a load of a power unit including an engine and a transmission, which are supported vibration bodies, the elastic body 3 has a sufficiently large thickness and a distortion when subjected to vertical deformation. It is formed thicker toward the inner circumference so as to be substantially uniform on the inner circumference side and the outer circumference side.
[0015]
The case 11 in the first mounting member 1, the cup-shaped flange 21 and the inner cylinder 22 in the second mounting member 2, and the elastic body 3 form an integral vulcanized molded body. That is, in the vulcanized molded body, the case 11, the cup-shaped flange 21 and the inner cylinder 22 connected to each other are positioned and set in a predetermined rubber vulcanization mold (not shown), and the mold is clamped. An unvulcanized rubber material is filled into a molding cavity defined between the case 11 and the cup-shaped flange 21 and the inner cylinder 22 by a mold, and is heated and pressurized to vulcanize the elastic body 3. And vulcanization bonding of the elastic body 3 to the case 11, the cup-shaped flange 21 and the inner cylinder 22 at the same time.
[0016]
The elastic body 3 has an elastic film 31 extending from the outer peripheral portion thereof so as to cover the inner peripheral surface of the case 11 of the first mounting member 1 and an elastic film extending from the inner peripheral portion so as to cover the inner surface of the cup-shaped flange 21. The film 32 is formed continuously.
[0017]
A caulking portion 11b having a substantially U-shaped cross section is formed at an upper end portion of the case 11 in the first mounting member 1, and an outer peripheral edge 4a of the diaphragm 4, an outer peripheral portion of the partition wall 5, and a lower flange portion 6a of the cover 6 are mutually connected. It is fixed to the caulking portion 11b in a state of being closely contacted. The outer peripheral portions of the partition wall 5 and the cover 6 are sealed by an elastic film 31 extending from the inner peripheral surface of the case 11 to the inner surface of the caulking portion 11b.
[0018]
The diaphragm 4 is made of a rubber-like elastic material, is formed to be sufficiently thinner than the elastic body 3, and is formed in a substantially flat plate shape to allow smooth displacement and deformation. . The outer peripheral edge 4 a is hermetically fixed between the partition wall 5 and the cover 6.
[0019]
The partition 5 provided to separate the liquid sealing space between the elastic body 3 and the diaphragm 4 into a lower liquid chamber A on the elastic body 3 side and an upper liquid chamber B on the diaphragm 4 side includes an upper plate 51 and a lower plate 52. And a movable plate 53.
[0020]
The upper plate 51 and the lower plate 52 are formed of metal or synthetic resin into a disk shape. A circumferential groove extending in the circumferential direction is formed in the outer peripheral portion of the lower surface of the upper plate 51, and this groove is formed in a substantially C shape in the circumferential direction by the lower plate 52 existing so as to block the lower side. An extending orifice C is formed. One end of the orifice C is opened to the lower liquid chamber A through an opening 52a opened in the lower plate 52, and the other end is opened to the upper liquid chamber B via an opening 51a opened in the upper plate 51. I have.
[0021]
On the inner peripheral side of the orifice C, a flat annular pressure receiving chamber D is formed by a shallow annular concave portion formed on the lower surface of the upper plate 51 and the lower plate 52 below the concave portion. The movable plate 53 is made of a rubber-like elastic material and formed into a flat annular shape, and is loosely inserted so as to partition the pressure receiving chamber D up and down.
[0022]
The lower gap of the movable plate 53 in the pressure receiving chamber D is opened to the lower liquid chamber A through a number of pressure guide ports (only one is shown in FIG. 1) 52b opened in the lower plate 52, and the pressure receiving chamber D is opened. The upper gap of the movable plate 53 in D is opened to the upper liquid chamber A through a number of pressure guide ports (only one is shown in FIG. 1) 51 b opened in the upper plate 51.
[0023]
The cover 6 has a cup-like shape and protects the thin diaphragm 4 from the outside. As shown in FIG. 2, the cover 6 has a thin film-like elastic layer 61 made of a rubber-like elastic material. And a metal plate 61, 62 such as a steel plate sandwiched from both sides in the thickness direction. As shown in FIG. 1, the lower end flange portion 6 a of the cover 6 is sandwiched between the outer peripheral edge 4 a of the diaphragm 4 and the elastic film 31 attached to the inner surface of the case 11 of the first mounting member 1. In this state, it is fixed to the caulking portion 11b of the case 11, and the upper bottom portion 6b surrounds the diaphragm 4 via a space S above the diaphragm 4. Reference numeral 6c is a ventilation hole for ensuring smooth displacement of the diaphragm 4.
[0024]
The liquid sealing space including the lower liquid chamber A, the upper liquid chamber B, the orifice C, and the pressure receiving chamber D is filled with a hydraulic fluid having an appropriate viscosity, such as silicone oil. The hydraulic fluid is obtained by incorporating the partition wall 5, the diaphragm 4 and the cover 6 into the caulking portion 11b of the case 11 integrated with the elastic body 3 and the second mounting member 2 in a liquid such as the silicone oil stored in the liquid tank. By caulking and fixing, a part of the liquid is confined.
[0025]
In the liquid-filled mount configured as described above, the mounting arm 12a of the outer ring 12 in the first mounting member 1 is connected to the vehicle body frame side, and the second mounting member 2 is connected to the engine-side bracket 24. The power unit including the engine is elastically suspended and supported on the vehicle body frame. In this mounting state, when the vertical vibration V is input from the power unit or the road surface while the vehicle is traveling, the first mounting member 1 and the second mounting member 2 are repeatedly vertically displaced relative to each other, and the two mounting members 1 and 2 are repeatedly displaced. The vibration V is effectively absorbed by the elasticity of the elastic body 3 that undergoes repeated deformation between them.
[0026]
When the input vibration V is a continuous and small-amplitude medium / high-frequency vibration caused by, for example, engine vibration of the engine, the movable plate 53 is repeatedly displaced up and down in the pressure receiving chamber D, so that the elastic body The change in the liquid pressure in the lower liquid chamber A due to the deformation of 3 is absorbed. For this reason, the dynamic spring of the mount is lowered, and the transmission of vibration is effectively insulated.
[0027]
Further, when the input vibration V is a large-amplitude low-frequency vibration caused by a shock input caused by, for example, riding on or stepping off a road surface step portion while the vehicle is traveling, the lower liquid chamber A is deformed due to the deformation of the elastic body 3. Since the volume greatly changes, the hydraulic fluid repeatedly flows through the orifice C due to the liquid column resonance while the diaphragm 4 is being displaced. Therefore, the change in the pressure in the lower liquid chamber A is absorbed, and the dynamic spring constant is reduced. At this time, a high damping is generated due to the viscosity in the orifice C, so that the vibration V is quickly converged.
[0028]
Here, in the above-described large-amplitude low-frequency vibration, for example, in the process in which the first mounting member 1 is displaced upward together with the vehicle body frame or the second mounting member 2 is displaced downward together with the power unit, the case of the first mounting member 1 As the elastic body 3 is compressed between the lower small diameter part 11a of the lower part 11 and the cup-shaped flange 21 of the second mounting member 2, the volume of the lower liquid chamber A is enlarged. The hydraulic pressure in the chamber A decreases. At this time, the hydraulic fluid flows from the upper fluid chamber A to the lower fluid chamber A through the orifice C so as to eliminate the lowering of the fluid pressure in the lower fluid chamber A, but when the volume of the lower fluid chamber A is rapidly increased. In some cases, the liquid pressure in the lower liquid chamber A instantaneously drops below the saturated vapor pressure. In this case, cavitation occurs such that bubbles are generated in the liquid and the bubbles disappear after the subsequent increase in the liquid pressure. Then, an unusual sound is generated due to an impact accompanying the generation and disappearance of the bubble.
[0029]
The abnormal sound generated in the working fluid by the cavitation is radiated from the diaphragm 4 as an air transmission sound to the space S above the diaphragm 4 and transmitted to the upper bottom portion 6b of the cover 6. However, since the vibration of the cover 6 is suppressed by the vibration damping action of the thin elastic layer 61 made of a rubber-like elastic material, the radiation of abnormal noise from the cover 6 to the outside can be reduced.
[0030]
The elastic layer 61 may be made of a rubber-like elastic material, or may be made of a synthetic resin material having excellent vibration damping properties.
[0031]
Next, FIG. 3 is a longitudinal sectional view showing a cover 6 and a spring-mass system 64 provided on the cover 6 as a second embodiment of the liquid-filled mount according to the present invention. In this embodiment, the cover 6 is formed of a metal plate such as a steel plate in a shape in which a cup is turned down, has a ventilation hole 6c, and has a lower end flange portion 6a provided with a diaphragm 4 like the embodiment of FIG. Is fixed to the caulked portion 11b of the case 11 while being sandwiched between the outer peripheral edge 4a of the first mounting member 1 and the elastic film 31 attached to the inner surface of the case 11 in the first mounting member 1, and the upper bottom portion 6b is The diaphragm 4 is surrounded by the upper space S.
[0032]
Inside (lower side) of the upper bottom 6b of the cover 6, a shielding plate 64a that covers substantially the entire surface except the outer peripheral portion from below, and elasticity for connecting the shielding plate 64a to the inner surface (lower surface) of the upper bottom 6b. A spring-mass system 64 including a coupling body 64b is provided. The resonance frequency of the spring-mass system 64, which is determined by the mass of the shielding plate 64a made of a metal disk or the like and the spring constant (hardness) of the elastic coupling body 64b made of a rubber-like elastic material, is caused by abnormal noise generated by cavitation in the hydraulic fluid. It is set lower than the frequency range.
[0033]
The other parts, that is, the configuration of the mount main body part including the first mounting member 1, the second mounting member 2, the elastic body 3, the diaphragm 4, the partition wall 5, and the like are the same as those in FIG. 1 described above.
[0034]
According to the above configuration, in the input process of the large-amplitude low-frequency vibration, the abnormal noise generated by the cavitation in the hydraulic fluid due to the rapid expansion of the volume of the lower fluid chamber A shown in FIG. 4 is transmitted as air transmission sound to the upper space S and transmitted to the shielding plate 64 a of the spring-mass system 64. However, since the resonance frequency of the spring-mass system 64 is in a lower frequency range than the frequency of abnormal noise due to cavitation, the vibration of the shielding plate 64a is suppressed. In addition, the transmitted vibration from the shielding plate 64a to the upper bottom portion 6b of the cover 6 is absorbed by the viscoelasticity of the elastic coupling body 64b, so that the radiation of abnormal noise from the cover 6 to the outside can be reduced.
[0035]
Next, FIG. 4 is a longitudinal sectional view showing a cover 6 and a spring-mass system 64 provided on the cover 6 as a third embodiment of the liquid-filled mount according to the present invention. In this embodiment, the cover 6 is similar to the second embodiment described above, and includes a mount body portion including the first attachment member 1, the second attachment member 2, the elastic body 3, the diaphragm 4, the partition 5, and the like. Is similar to that of FIG. 1 described above.
[0036]
Outside (upper side) the upper bottom portion 6b of the cover 6, a shielding plate 64a that covers substantially the entire surface except the outer peripheral portion from above, and an elastic connecting body that connects the shielding plate 64a to the outer surface (upper surface) of the upper bottom portion 6b. A spring-mass system 64 is provided. The resonance frequency of the spring-mass system 64, which is determined by the mass of the shielding plate 64a made of a metal disk or the like and the spring constant (hardness) of the elastic coupling body 64b made of a rubber-like elastic material, is caused by abnormal noise generated by cavitation in the hydraulic fluid. It is set lower than the frequency range.
[0037]
According to the above configuration, in the input process of the large-amplitude low-frequency vibration, the abnormal noise generated by the cavitation in the hydraulic fluid due to the rapid expansion of the volume of the lower fluid chamber A shown in FIG. 4 is radiated as air transmission sound to the upper space S, and vibrates the upper bottom portion 6b of the cover 6. However, a shielding plate 64a is disposed outside the shielding plate 64a, and the resonance frequency of the shielding plate 64a (spring-mass system 64) is in a lower frequency range than the frequency of abnormal noise due to cavitation. Since the vibration is absorbed by the elasticity, the vibration of the shielding plate 64a is suppressed. For this reason, the radiation of abnormal noise from the cover 6 to the outside can be shielded.
[0038]
【The invention's effect】
According to the liquid-filled mount according to the first aspect of the present invention, since the cover for protecting the diaphragm from the outside has a structure in which the elastic layer is sandwiched between the metal plates on both sides in the thickness direction, abnormal noise caused by cavitation in the liquid chamber. Is suppressed by the damping characteristic of the elastic layer, and therefore, radiation of noise from the cover can be effectively suppressed.
[0039]
According to the liquid-filled mount according to the second aspect of the present invention, abnormal noise is generated inside or outside the cover by a spring-mass shielding plate having a resonance frequency lower than a frequency range of abnormal noise generated in the working fluid. Since shielding is performed, radiation of noise from the cover can be effectively suppressed.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a liquid-filled mount according to a first embodiment of the present invention.
FIG. 2 is a vertical sectional view showing a cover of the liquid-filled mount of FIG. 1 separately.
FIG. 3 is a longitudinal sectional view showing a cover and a spring-mass system provided on the cover in a liquid-filled mount according to a second embodiment of the present invention.
FIG. 4 is a longitudinal sectional view showing a cover and a spring-mass system provided on the cover in a liquid-filled mount according to a third embodiment of the present invention.
[Explanation of symbols]
1 First mounting member 2 Second mounting member 24 Engine side bracket (supported vibration body side)
3 Elastic body 4 Diaphragm 5 Partition wall 6 Cover 61 Elastic layer 62, 63 Metal plate 64 Spring-mass system 64a Shielding plate 64b Elastic connector A Lower liquid chamber B Upper liquid chamber C Orifice D Pressure receiving chamber

Claims (2)

A cylindrical first mounting member (1) connected to the support side, a second mounting member (2) arranged on the inner periphery thereof and connected to the supported vibrator side (24), and the first mounting member An elastic body (3) joined between (1) and the second mounting member (2), and a diaphragm (4) above and having an outer peripheral edge (4a) sealed to the first mounting member (1). ) And the liquid sealing space between the elastic body (3) and the diaphragm (4) into a lower liquid chamber (A) on the elastic body (3) side and an upper liquid chamber (B) on the diaphragm (4) side. A partition (5) formed with an orifice (C) communicating with the lower liquid chamber (A) and the upper liquid chamber (B) and a cover (6) surrounding the outside of the diaphragm (4). The cover (6) has a structure in which the elastic layer (61) is sandwiched between metal plates (62, 63) from both sides in the thickness direction. Fluid-filled mount according to claim. A cylindrical first mounting member (1) connected to the support side, a second mounting member (2) arranged on the inner periphery thereof and connected to the supported vibrator side (24), and the first mounting member An elastic body (3) joined between (1) and the second mounting member (2), and a diaphragm (4) above and having an outer peripheral edge (4a) sealed to the first mounting member (1). ) And the liquid sealing space between the elastic body (3) and the diaphragm (4) into a lower liquid chamber (A) on the elastic body (3) side and an upper liquid chamber (B) on the diaphragm (4) side. A partition (5) formed with an orifice (C) communicating with the lower liquid chamber (A) and the upper liquid chamber (B) and a cover (6) surrounding the outside of the diaphragm (4). A shielding plate (64a) inside or outside the cover (6) and the shielding plate (64a) attached to the cover (6). A spring-mass system (64) comprising an elastic coupling body (64b) to be connected, wherein the resonance frequency of the spring-mass system (64) is set lower than a frequency range of abnormal noise generated in the liquid. Liquid-filled mount.

Images