JP3934294B2 - Liquid filled vibration isolator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid-filled vibration isolator.
[0002]
[Prior art]
It is known that vibrations occur in a wide frequency range in an automobile engine, in particular, engine shake near 10 Hz, idle vibration near 20 to 40 Hz, booming noise and acceleration vibration near 80 to 200 Hz. Therefore, as a vibration isolator used for supporting a power unit including an engine, an apparatus capable of effectively reducing vibrations in a plurality of frequency ranges has been developed (see, for example, JP-A-10-122294) ).
[0003]
As this type of vibration isolator, for example, a so-called double orifice type liquid-filled vibration isolator as shown in FIG. 6 is known.
[0004]
The liquid-filled vibration isolator 56 includes a first partition member 66 in a liquid chamber 64 defined between a rubber elastic body 60 connecting a pair of mounting members 58a and 58b and a first diaphragm 62 made of rubber. The first partition member 66 defines the liquid chamber 64 into a main liquid chamber 68 on the rubber elastic body 60 side and a first sub liquid chamber 70 on the first diaphragm 62 side. A second partition member 72 is press-fitted into the first partition member 66, and the first partition member 66 and the second partition member 72 have a substantially disk shape, and the thickness of the central portion is the periphery. A rubber second diaphragm 74 formed to be thicker than the thickness of the portion is sandwiched. The second partition member 72 and the second diaphragm 74 define a second sub liquid chamber 76 located in the first partition member 66.
[0005]
When vibration is input to the liquid filled vibration isolator 56 and liquid flows from the main liquid chamber 68 into the second sub liquid chamber 76, the second diaphragm 74 is bent and deformed.
[0006]
A curve e in FIG. 7 shows the reaction force characteristic of the second diaphragm 74 at this time.
[0007]
The thickness of the inner peripheral side of the portion sandwiched between the first partition member 66 and the second partition member 72 is relatively thin compared to the thickness of the center portion of the second diaphragm 74. Although it is easily bent and deformed with a small load at the initial stage of deformation, when the second diaphragm 74 comes into contact with the regulation protrusion 78 formed on the inner peripheral side of the first partition member 66, The bending deformation of the second diaphragm 74 is greatly restricted.
[0008]
That is, a substantially constant small reaction force is generated in the second diaphragm 74 until the second diaphragm 74 comes into contact with the restriction projection 76, and when the second diaphragm 74 comes into contact with the restriction projection 76, the second diaphragm 74 becomes large. Reaction force is generated.
[0009]
Therefore, the liquid filled vibration isolator 56 can effectively reduce vibrations in different frequency ranges such as engine shake and idle vibration.
[0010]
[Problems to be solved by the invention]
However, in the above-described configuration, when a very large load abruptly acts on the second diaphragm 74 when starting the engine or traveling on a rough road, the second diaphragm 74 is restricted from the restricting projection of the first partition member 66. There is a possibility that an unpleasant noise may occur due to the collision with 78.
[0011]
As a device that can prevent the generation of such abnormal noise, there is a liquid-filled vibration isolator 80 shown in FIG. The liquid-filled vibration isolator 80 is configured in substantially the same manner as the liquid-filled vibration isolator 56 of FIG. 6 described above, but in this liquid-filled vibration isolator 80, the first partition member 66 has a restricting projection. A configuration corresponding to 78 is not formed, and the second diaphragm 74 has a substantially disk shape and is vulcanized and bonded to the inner peripheral surface of the annular metal fitting 82. The metal fitting 82 is press-fitted into the inner peripheral side of the first partition member 66. When the metal fitting 82 is press-fitted, the second diaphragm 74 is squeezed and the second diaphragm 74 is bent. In the state, it is assembled to the first partition member 66.
[0012]
That is, the liquid-filled vibration isolator 80 shown in FIG. 8 has an initial reaction force generated in the second diaphragm 74 by bending the second diaphragm 74 in advance as shown by a curve f in FIG. When the volume of the second sub-liquid chamber 76 increases with the inflow of liquid from the main liquid chamber 68 and the deflection of the second diaphragm 74 is absorbed, A large reaction force is generated in the second diaphragm 74.
[0013]
Therefore, the liquid-filled vibration isolator 80 shown in FIG. 8 effectively reduces vibrations in different frequency ranges such as engine shake and idle vibration, similarly to the liquid-filled vibration isolator 56 shown in FIG. 6 described above. be able to.
[0014]
Further, the liquid-filled vibration isolator 80 shown in FIG. 8 does not have a configuration corresponding to the regulation protrusion 78 of the liquid-filled vibration isolator 56 shown in FIG. Can be prevented.
[0015]
However, in the liquid filled type vibration isolator 80 shown in FIG. 8, the metal fitting 82 is attached to the second diaphragm 74, so that the manufacturing cost increases.
[0016]
[Means for Solving the Problems]
Accordingly, a first aspect of the present invention, the mounting member and the vehicle body-side mounting member of the power unit side that is arranged opposite to each other, and a rubber elastic body for connecting together the pair of mounting members, the pair of mounting members A first diaphragm that forms a liquid chamber between the rubber elastic body and the rubber elastic body, and is disposed in the liquid chamber and fixed to either one of the pair of attachment members, A first partition member defining a liquid chamber into a main liquid chamber on the rubber elastic body side and a first sub liquid chamber on the first diaphragm side; a second partition member press-fitted into the first partition member; A second sub-diaphragm defined by the second diaphragm sandwiched and fixed by the first partition member and the second partition member, the second diaphragm and the second partition member, and located inside the first partition member A liquid enclosure having a liquid chamber A vibration damping device, when the second partition member is press-fitted in the first partition member, so that the outer peripheral edge of the second diaphragm is moved to the inner circumferential side by the second partition member and the first partition member It is characterized by being compressed and being bent on the inner peripheral side of the second diaphragm. Thus, the initial reaction force generated in the second diaphragm becomes a substantially constant small reaction force, and the volume of the second sub liquid chamber increases with the inflow of liquid from the main liquid chamber. When the deflection of the diaphragm is absorbed, the reaction force generated in the second diaphragm becomes large.
[0017]
The invention according to claim 2 is characterized in that, in the invention according to claim 1, the second diaphragm is bonded to the first partition member and the second partition member. As a result, the initial compression amount of the outer peripheral edge of the second diaphragm sandwiched between the first partition member and the second partition member is always reliably maintained.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
[0019]
The liquid-filled vibration isolator 2 includes a metal attachment member 4 attached to the power unit side serving as a vibration generation source and a metal attachment member 6 attached to the vehicle body, and these attachment members 4 and 6 are mutually connected. The rubber elastic bodies 8 are connected so as to face each other. The mounting member 6 is composed of a bottom metal fitting 6a on a bottomed cylinder and a substantially cylindrical upper metal fitting 6b. The lower end portion of the metal fitting 6b, that is, the lower end portion in FIG. 1 is caulked to couple them together. The inner peripheral surface of the upper metal fitting 6b is covered with a thin coating portion 8a extending from the rubber elastic body 8.
[0020]
A first diaphragm 12 made of a rubber material, which is thin and has a substantially disk shape, is attached inside the attachment member 6.
[0021]
Between the first diaphragm 12 and the rubber elastic body 8, a liquid chamber 14 in which a liquid is sealed is defined.
[0022]
The liquid chamber 14 is further defined into a main liquid chamber 18 and a first sub-liquid chamber 20 by a substantially cylindrical metal first partition member 16 attached to the mounting member 6.
[0023]
The first partition member 16 has a flange-like flange portion 22 having a diameter larger than the outer diameter of the power unit side end portion, that is, the upper end portion in FIG. 1, at the vehicle body side end portion, that is, the lower end portion in FIG. Is formed. The outer peripheral edges of the flange portion 22 and the first diaphragm 12 are sandwiched between the lower end portion of the upper metal fitting 6b together with the outer peripheral flange 10 of the bottom metal fitting 6a, and are fixed by caulking. Further, the outer peripheral surface of the first partition member 16 is in close contact with the inner peripheral surface of the upper metal fitting 6b via the coating 8a of the rubber elastic body 8.
[0024]
A groove 24 is formed on the outer peripheral surface of the first partitioning member 16 so as to make a substantially spiral turn around the outer peripheral surface. The groove 24 has one end communicating with the main liquid chamber 18 at the end of the first partition member 16 on the power unit side, and the other end of the groove 24 at the end of the first partition member 16 on the vehicle body side. One sub liquid chamber 20 communicates.
[0025]
That is, the first orifice that communicates the main liquid chamber 18 and the first sub liquid chamber 20 between the outer peripheral surface of the first partition member 16 and the inner peripheral surface of the upper metal fitting 6b by the groove 24. A passage 26 is formed.
[0026]
Further, the inner peripheral side of the end portion of the first partition member 16 on the vehicle body side has a reduced inner diameter in a substantially step shape over the entire periphery. An annular groove 30 that opens toward the end of the first partition member 16 on the power unit side is formed in the reduced diameter portion 28 over the entire circumference.
[0027]
A second partition member 32 having a substantially bottomed cylindrical shape is press-fitted into the first partition member 16. The second partition member 32 is press-fitted so that the bottomed end portion 34 is located on the main liquid chamber 18 side and the open end portion 36 is located on the first sub liquid chamber 20 side.
[0028]
In the second partition member 32, the outer peripheral surface in the vicinity of the bottomed end portion 34 is a press-fit surface 38, and the outer diameter on the opening end portion 36 side is larger than the outer diameter in the vicinity of the bottomed end portion 34. It is formed slightly smaller.
[0029]
The bottomed end portion 34 is formed with a flange-like flange portion 40 that contacts the end surface of the power unit side end portion of the first partition member 16 over the entire circumference.
[0030]
On the outer peripheral surface of the second partition member 32, a groove 42 having a length that substantially goes around the outer peripheral surface is formed. One end of the second orifice passage 44 formed by the groove 42 and the inner peripheral surface of the first partition member 16 communicates with the main liquid chamber 18, and the other end is a second sub liquid chamber which will be described later. 46 communicates.
[0031]
The length of the first orifice passage 26 is formed to be longer than the length of the second orifice passage 44. The sectional area of the first orifice passage 26 is set smaller than the sectional area of the second orifice passage 44.
[0032]
Between the inner peripheral surface of the vehicle body side end of the first partition member 16 and the open end 36 of the second partition member 32, a rubber second diaphragm 48 having a substantially disc shape is sandwiched and fixed. ing.
[0033]
A second sub liquid chamber 46 adjacent to the first sub liquid chamber 20 is interposed between the second diaphragm 48 and the bottomed end portion 34 of the second partition member 32 via the second diaphragm 48. Is defined.
[0034]
The second diaphragm 48 has the outer peripheral edge 50 engaged with the annular groove 30 of the first partition member 16, and the second partition member 32 is press-fitted into the first partition member 16. The outer peripheral edge 50 is compressed.
[0035]
Since the outer peripheral side of the second diaphragm 48 is in close contact with the inner peripheral surface of the reduced diameter portion 28 of the first partition member 16, the inner peripheral side of the second diaphragm 48 is bent by this compression. Become.
[0036]
Since the second diaphragm 48 of the liquid-filled vibration isolator 2 is assembled in a bent state, the initial reaction force generated in the second diaphragm 48 is reduced to a substantially constant small reaction force as shown in FIG. When the volume of the second sub liquid chamber 46 increases with the inflow of liquid from the main liquid chamber 18 and the deflection of the second diaphragm 48 is absorbed, the second diaphragm 48 is absorbed. A large reaction force is generated.
[0037]
Therefore, as shown in FIG. 3, the vibration in the frequency range around 10 Hz such as engine shake is effectively reduced by a large loss factor. A curve a and a curve b in FIG. 3 indicate the loss factor and the dynamic spring constant of the second diaphragm 48, respectively.
[0038]
Moreover, as shown in FIG. 4, vibration in the frequency range of 20 to 30 Hz such as idle vibration is effectively reduced with a small dynamic spring constant. A curve c in FIG. 4 indicates the dynamic spring constant of the second diaphragm, and a curve d indicates the conventional dynamic spring constant.
[0039]
In the liquid-filled vibration isolator 2 configured as described above, the outer peripheral edge 50 of the second diaphragm 48 is compressed by the first partition member 16 and the second partition member 32, thereby bending the second diaphragm 48. Therefore, vibrations in a plurality of frequency ranges can be reduced without causing an increase in manufacturing cost due to an increase in the number of parts.
[0040]
In addition, even if the second diaphragm 48 is greatly bent, it does not interfere with the second diaphragm 48, so that the generation of abnormal noise can be reliably prevented.
[0041]
As shown in FIG. 5, the adhesive 52 is preliminarily applied to the outer peripheral edge 50 of the second diaphragm 48 sandwiched between the first partition member 16 and the second partition member 32. It is possible to reliably prevent the second diaphragm 48 from slipping out between the first partition member 16 and the second partition member 32, and the outer peripheral edge 50 always has the first partition member 16 and the second partition member. It is in a state of being in close contact with the member 32, the initial compression amount is reliably maintained, and the desired amount of bending can be reliably given to the second diaphragm 48. The expected performance of the liquid-filled vibration isolator 2 Can be definitely obtained.
[0042]
【The invention's effect】
According to the first aspect of the present invention, the outer peripheral edge of the second diaphragm can be compressed by press-fitting the second partition member into the first partition member, so that the second diaphragm can be bent. It is possible to prevent the generation of abnormal noise from the liquid-encapsulated vibration isolator without degrading the performance of the encapsulated vibration isolator or increasing the manufacturing cost.
[0043]
According to the second aspect of the invention, it is possible to reliably prevent the second diaphragm from coming out from between the first partition member and the second partition member, and the outer peripheral edge of the second diaphragm is always Since the initial compression amount is maintained, the expected performance of the liquid-filled vibration isolator can be reliably obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a liquid-filled vibration isolator according to the present invention.
FIG. 2 is a reaction force characteristic diagram of a second diaphragm of the liquid filled type vibration isolator according to the present invention.
FIG. 3 is a damping characteristic diagram of the liquid filled type vibration isolator according to the present invention.
FIG. 4 is a dynamic spring characteristic diagram of the liquid-filled vibration isolator according to the present invention.
FIG. 5 is a cross-sectional view of a main part of a liquid filled type vibration damping device according to a second embodiment of the present invention.
FIG. 6 is a cross-sectional view of a conventional liquid-filled vibration isolator.
FIG. 7 is a reaction force characteristic diagram of a second diaphragm of a conventional liquid-filled vibration isolator.
FIG. 8 is a cross-sectional view of a conventional liquid-filled vibration isolator.
[Explanation of symbols]
2 ... Liquid-sealed vibration isolator 16 ... 1st partition member 20 ... 1st subliquid chamber 28 ... Reduced diameter part 32 ... 2nd partition member 46 ... 2nd subliquid chamber 48 ... 2nd diaphragm 50 ... Outer periphery

Claims (2)

An attachment member on the power unit side and an attachment member on the vehicle body side that are arranged opposite to each other;
A rubber elastic body for connecting the pair of attachment members to each other;
A first diaphragm fixed to one of the pair of mounting members and forming a liquid chamber between the rubber elastic body;
The liquid chamber is disposed in the liquid chamber and fixed to one of the pair of mounting members, and the liquid chamber is divided into a main liquid chamber on the rubber elastic body side and a first sub liquid chamber on the first diaphragm side. A first partition member formed;
A second partition member press-fitted into the first partition member;
A second diaphragm clamped and fixed by the first partition member and the second partition member;
A liquid-filled vibration isolator having a second sub-liquid chamber defined by the second diaphragm and the second partition member and located inside the first partition member;
When the second partition member is press-fitted into the first partition member, the outer peripheral edge of the second diaphragm is compressed by the second partition member and the first partition member so as to move to the inner peripheral side, 2. A liquid-filled vibration isolator characterized by bending on the inner peripheral side of the two diaphragms. The liquid-filled vibration isolator according to claim 1, wherein the second diaphragm is bonded to the first partition member and the second partition member.

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