JP3767009B2 - Viscous fluid filled vibration isolator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an anti-vibration support device that is attached between a vibrating body and a support member in a vehicle, an industrial machine, or the like.
[0002]
[Prior art]
As a conventional viscous fluid-filled vibration isolator, a stirring plate provided in an internal liquid chamber is often used in a structure that is fixed to an end of an inner metal fitting. However, in the case of this structure, it is known that the dynamic spring constant increases as the viscous resistance increases, particularly in the high-frequency vibration band, and vibration insulation becomes disadvantageous.
In order to solve this phenomenon, a stirring plate is attached to the inner metal fitting through an elastic member as shown in FIG. 5, or a structure in which the stirring plate is floated and elastically attached to the inner metal fitting as shown in FIG. Has been proposed.
(For example, JP-A-59-73650, JP-A-61-52743)
[0003]
[Problems to be solved by the invention]
For the two examples described in the prior art, the effect of reducing the dynamic spring constant at the high frequency can be realized. On the other hand, the damping characteristic in the low frequency range, which was originally intended, is the inner metal fitting. In other words, the stirrer plate inevitably has a drawback that it decreases with a loss of viscous resistance due to the relative movement of the stirring plate. An object of the present invention is to provide a viscous fluid-filled vibration isolator that reduces the dynamic spring constant in the high frequency range without impairing the damping characteristics in the low frequency range.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the viscous fluid-filled vibration isolator proposed by the present invention includes a stirring plate that is provided in the liquid chamber and generates a damping force due to the flow resistance of the viscous fluid in accordance with the vertical vibration of the inner metal fitting. Installed to the end of the inner metal fitting in a state where a predetermined pre-compression is applied by an elastic member, and if a flow resistance exceeding a predetermined pre-compression load occurs, the stirrer plate floats with respect to the inner metal fitting It is characterized by comprising.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the viscous fluid-filled vibration isolator of the present invention has an inner metal fitting 10 provided with an assembly bolt to a vibrating body (not shown) and a bottom provided concentrically on the outer periphery thereof. An outer metal fitting 20 having a lid 22 and having an assembly hole 21 for a support member (not shown), and the inner metal fitting 10 and the outer metal fitting 20 are bonded to each other to elastically support a vibrating body (not shown). The rubber elastic body 30 to be attached, the viscous fluid 41 enclosed in the liquid chamber 40 surrounded by them, and the liquid chamber side end portion 12 of the inner metal fitting 10 are attached to the liquid chamber side end portion 12 by the stepped mounting bolts 70 via the elastic member 60. And the stirring plate 50 formed. The plate-like plate 80 is a stopper plate that is integrally attached to the inner metal fitting 10 to prevent the rubber elastic body 30 from being deformed excessively, and 91 is a rivet that seals the viscous fluid 41.
[0006]
The elastic member 60 shown here is a spring washer-like spring body, and the one with an initial height of 7 mm is compressed by 2.5 mm by setting the length of the first stepped bolt 70 to a predetermined length. It is fixed.
Since this elastic body 60 has a compression spring constant of 50 ^N / mm, the stirring plate 50 is pressed against the inner metal fitting end 12 by a biasing force of 250 ^N.
[0007]
Accordingly, when a force exceeding 250 ^N due to the flow resistance of the viscous fluid is applied to the stirring plate 50 in a direction away from the inner metal fitting end 12, the stirring plate 50 is separated from the inner metal fitting end 12, and from this state. When the direction of vibration is reversed and the force applied to the stirring plate 50 is reversed, the flow resistance of the viscous fluid disappears,
The stirring plate 50 is pushed back to the inner metal fitting end 12 again by the urging force of the elastic member.
At this time, a damping force due to the flow resistance of the viscous fluid is temporarily not generated, and as a result, the dynamic spring constant at a high frequency can be reduced.
[0008]
In general, since the resistance of the stirring plate in the viscous fluid is proportional to the speed, the viscous fluid-sealed vibration isolator of the present invention can be reduced by appropriately selecting the spring characteristics of the elastic member to be used and the precompression amount. In the high frequency vibration band, it is possible to obtain the same damping characteristics as in the past, and to prevent vibration transmission in the high frequency vibration band.
[0009]
Next, another example showing the embodiment of the present invention will be described with reference to FIG.
This figure shows the cross section of the Example which changed the structure of the elastic member in the Example of FIG. 1, and the stirring board, and uses the same number about another part.
That is, the elastic members 61 and 62 in this figure are made of rubber materials vulcanized and bonded to the upper and lower surfaces of the stirring plate 50, respectively. And assembled to the end of the inner metal fitting. In this case, a flow hole 51 for adjusting the flow resistance of the stirring plate 50 is provided in the stirring plate 50.
[0010]
Specifically, as shown in FIG. 3 (b), the elastic members 61 and 62 made of a rubber material is vulcanization bonded to the stirring plate 50 is molded by the height of the figure l _0, the inner fitting liquid chamber side When assembling to the end,
The stepped portion provided on the assembly bolts, there is a state of being compressed to l _1. In this case, the difference from the above embodiment is that when the compression spring constants of the elastic members 61 and 62 are K ₁ and K ₂ as shown in FIG. In this relationship, the combined spring constant K becomes K = K ₁ + K ₂ within the range of the compression amount a + b of the elastic members 61 and 62, and when it exceeds this range, each spring constant becomes a single spring constant, and K = K ₁ or K = K ₂ .
[0011]
In other words, in this case, even if the axial frequency of the inner metal fitting increases and the viscous resistance increases as the displacement speed increases, the reaction force is proportional to the displacement within the range of the preliminary compression amount of the elastic members 61 and 62. However, when the range is exceeded, the increase in reaction force is kept low,
When either one of the elastic members floats from the inner metal fitting 10 and returns to the reverse vibration direction, the resistance force of the viscous fluid does not act, and the transmission force is reduced against high-frequency, large-displacement vibrations. The effect to do is acquired more notably. Further, since the elastic members 61 and 62 are formed of a rubber-like elastic body, it is possible to prevent the occurrence of hitting sound or abnormal noise on the contact surface with the inner metal fitting end 12 or the bolt 70.
[0012]
Next, the principal part of the Example which shows other embodiment of this invention is shown in FIG. In this figure, the inner metal fitting end side of the stirring plate is formed of a rubber elastic body 61 which is vulcanized and bonded as in the above embodiment, and the opposing surface uses a metallic disc spring 63, and an elastic member. A cushioning material 65 made of a rubber-like elastic body is disposed between 63 and the stirring plate 50.
[0013]
The buffer member 65 can prevent abnormal noise when the elastic member 63 and the stirring plate 50 come into contact with each other by vibration.
【The invention's effect】
[0014]
As described above, in the present invention,
In low-frequency vibration with low vibration speed, the damping force due to viscous fluid is not reduced, and in high-frequency vibration with high vibration speed, the transmission force of vibration can be reduced and generated from each movable part accompanying vibration. Abnormal noise can also be prevented.
[Brief description of the drawings]
1 is a cross-sectional view showing an embodiment of a viscous fluid-filled vibration isolator of the present invention. FIG. 2 is another embodiment of the viscous fluid-filled vibration isolator of the present invention. FIG. 4 is a cross-sectional view of the main part of still another embodiment of the viscous fluid-filled vibration isolator of the present invention. FIG. 5 is a cross-sectional view of the prior art. It is sectional drawing which shows a prior art.
DESCRIPTION OF SYMBOLS 10 Inner metal fitting 11 Vibrating body attaching bolt 12 Inner metal end face 20 Outer metal fitting 21 Outer metal fitting attaching part 30 Rubber elastic body 40 Liquid chamber 41 Viscous fluid 50 Stirring plate 60, 61, 62, 63 Stirring plate 65 Buffer member 70 Stirring plate mounting bolt 90 Lid

Claims (3)

An inner metal fitting provided with means for attaching to a vibrating body, a bottomed cylindrical outer metal fitting provided concentrically on the outer periphery of the inner metal fitting and provided with means for attaching to a support, and the outer metal fitting A liquid rubber chamber is formed on the bottom side of the outer metal fitting by a cylindrical rubber elastic body that is connected and supports the vibrating body, and a circle that divides the liquid chamber in the axial direction at the end of the inner metal fitting in the liquid chamber. In the viscous fluid-sealed vibration isolator formed by attaching a plate-like stirring plate and filling the fluid chamber with a viscous fluid,
The viscous fluid-filled vibration isolator according to claim 1, wherein an elastic member provided at least on one side in the axial direction of the stirring plate is attached in a state of being pre-compressed by a predetermined amount in the axial direction of the inner metal fitting. The viscous fluid-sealed vibration isolator according to claim 1, wherein the elastic member is a spring body made of a rubber-like elastic material. 3. A viscous fluid-sealed antivibration system according to claim 1, wherein a buffer member made of a rubber-like elastic body is provided between the stirring plate or the inner metal fitting end portion with which the elastic member abuts. apparatus.

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