JPH0214571B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluid-filled mount which has a novel structure and which greatly improves the vibration isolation effect in a high frequency range above the secondary vibration range.

The present applicant previously disclosed in Japanese Patent Application No. 58-105509 that a mounting member connected to a vibration source and a base member for mounting the vibration source were connected by an elastic member, and the above-mentioned fluid chamber was formed inside the mounting member and the base member for mounting the vibration source. We proposed a fluid-filled mount in which a weight having an effective area larger than the effective area of an elastic member is supported in a horizontal floating manner.
According to this, the force that attempts to act on the base member from the mounting member via the elastic member is reliably applied to the fluid moving in the fluid chamber by the weight that moves up and down in response to changes in the relative position between the mounting member and the base member. Since it is absorbed, the dynamic magnification in the high frequency vibration region can be reduced to approximately zero, and therefore the high frequency vibration blocking effect can be significantly improved.

The present invention has been accomplished with the object of providing a fluid-filled mount with a novel structure that has the above advantages while increasing the degree of freedom in design.

In order to achieve the above object, the present invention provides a fluid-filled mount in which the mounting member and the base member are joined together at the inner and outer peripheries of an elastic member to form a fluid chamber therein. A communicating chamber with a relatively large area is formed by bulging toward the mounting member or base member, and a weight is floatingly supported across the chamber in the chamber, and the fluid chamber is opened to the atmosphere. The effective area of the weight, which is determined as the ability to contribute to fluid movement per unit relative displacement with the weight, is calculated as the ability to contribute to fluid movement per unit relative displacement between the mounting member and the base member when the fluid chamber is opened to the atmosphere. It was set to be larger than the effective area of the elastic member required for capacity. The gist is that.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a central vertical cross-sectional view of the mount of the first embodiment, in which the base member 2 has a flange piece 21 at the upper end of a tapered hollow body 20 that expands upward, and a cross-sectional core that opens inward at the lower end. The mounting member 3 includes a hollow body 30 in which a cylindrical portion 33 having a large diameter is formed at the top of a funnel portion 31 having a diameter sufficiently smaller than that of the hollow body 20 through a tapered portion 32.
and a disc body 35 whose peripheral edge is inserted into a clamping part 34 provided at the upper end of the cylindrical part 33 and crimped.

The flange piece 21 of the base member 2 has mounting holes 22 for connecting to a fixed member such as a vehicle body frame, and the center of the disc body 35 of the mounting member 3 has a mounting screw 36 connected to a vibration source such as an engine. It is set up.

Then, the outer periphery of a thick-walled, umbrella-shaped elastic member 4 made of a rubber material is baked onto the inner periphery of the hollow body 20 of the base member 2, and the inner periphery of this elastic member 4 is baked onto the outer periphery of the funnel portion 31 of the mounting member 3. Also, base member 2
Into the clamping part 23, the peripheral edge of the orifice plate 5 having an orifice 51 in the center and a ring plate 61 which abuts the lower surface and has the peripheral edge of the diaphragm 6 baked are inserted, and the clamping part 23 is swaged. Holds orifice plate 5 and diaphragm 6.

Furthermore, a sleeve 9 is fitted onto the inner periphery of the cylindrical portion 33 of the mounting member 3, and the outer periphery of an annular elastic body 8 made of a rubber material is baked onto the inner periphery of the sleeve 9. Burn the meat disc-shaped weight 7. A truncated inverted conical portion 71 having a smaller diameter than the funnel portion 31 is integrally formed to hang down from the lower surface of the weight 7, and this inverted conical portion 71 faces into the funnel portion 31.

Thus, the main fluid chamber 11 is located above the orifice plate 5.
However, sub-fluid chambers 12 are formed in the lower part, and the fluid-filled mount 1 is constructed by filling and sealing liquid in both chambers 11 and 12.

Next, the operation will be explained based on FIG. 2, which shows the mount 1 in half cutaway, and FIG. 3, which shows the elastic member 4 portion.

In the high frequency region above the secondary vibration region, the weight 7 is almost stationary due to inertia, so when the mounting member 3 supporting the weight 7 moves downward, the weight 7 acts to suck the fluid, and the main fluid chamber The fluid pressure inside 11 becomes low, and as a result, the elastic member 4 is attracted toward the main fluid chamber 11 (see FIG. 2). For this reason, a force _F1 is generated in the elastic member 4 that pushes the base member 2 upward as shown in FIG.

On the other hand, due to the downward displacement of the mounting member 3, a downward force _F2 is generated on the base member 2 through the elastic member 4.

Therefore, in the present invention, each parameter described below is set to an appropriate value so that F ₁ and F ₂ cancel each other out, and the dynamic magnification (|K ^* |/ks) in the high frequency vibration region is made approximately zero. As a result, vibration transmission can be significantly reduced.

The specific analysis is described below.

First, as shown in FIG. 2, let SE be the effective area of the elastic member 4 that contributes to the movement of fluid in the main fluid chamber 11 of the mount 1, and let S _E be the effective area of the elastic member 4 that does not contribute to the movement of fluid. The area is S _B , and the passage area at the lower end of the funnel portion 31 of the mounting member 3 is S _H. Therefore, the effective area of the elastic member 4 is (S _E
+S _H ). The effective area of the orifice plate 5 is S _O , and the weight 7 and the elastic body 8 that supports it are
Let _SW be the effective area near the inner circumference of . Here S _O
= S _E + S _H + S _B.

Next, if we model the above mount 1, the 4th
As shown in the figure, the spring constant of the effective area S _E part that determines the fluid movement ability of the elastic member 4 with a spring constant k is ak, and the spring constant of the effective area S _W part of the weight 7 is dk. It is. Here, both a and d are arbitrary constants. If the displacement of the vibration source is x, then the displacement of the S _E section is x _E and the displacement of the SW _section is x _W , and the fluid pressure is P, and the orifice plate 5 is finally The force transmitted to the base member 2 through F
shall be.

In the above, in the high frequency vibration region such as secondary vibration, since x _W ≈0, it can be expressed as F=kx+PS _O −PS _B =kx+P(S _E +S _H . . . (i)).

On the other hand, since x _W ≒0, x _E ≒0, so akx=−P(S _W −S _E −S _H ) ∴P=−akx/S _W −S _E −S _H ……(ii) It is.

Therefore, by substituting equation (ii) into equation (i), we get F=kx−akx(S _E +S _H )/S _W −S _E −S _H =kx{1−a(S _E +S _H )/S _W −S _E −S _H } ...(iii) is obtained.

Therefore, by selecting S _W =(1+a)(S _E +S _H ), it can be seen from equation (iii) that F=0.

Therefore, S _W >(S _E +S _H ) is the condition that satisfies the above condition, that is, the effective area of the weight 7 may be configured to be larger than the substantial effective area of the elastic member 4.

By the way, since the elastic member 4 that connects the mounting member 2 and the base member 3 has a complex umbrella-shaped shape with shearing properties, its effective area S _E cannot be determined by simple calculation. ,
Furthermore, since the elastic body 8 supporting the weight 7 is also annular in shape with shearing properties, its effective area _SW cannot be easily determined.

Therefore, we actually conducted a test and determined that each effective area S _E ,
Find _SW .

First, we will explain how to find the effective area S _E of the mounting member 4.

First, as shown in FIG. 5, the lower end of the hollow body 130 with the funnel part 131 facing upward is closed with a lid plate 139, and the inner periphery of the mounting member 4 is fixed to the outer periphery of the funnel part 131.
In this way, the tube body 100 is fixed at the flange portion 101 to the upper part of the elastic member 4 forming an inverted umbrella shape.

After the liquid is injected into the tube 100 and kept stationary, a forcible displacement of 1 mm is applied to the hollow body 130 from below as shown in FIG. As a result, the liquid level rises inside the tube 100, and the amount of volume movement Vmm ³ is actually measured.

Therefore, we obtain S _E =V/l-S _H.

Next, we will explain how to find the effective area S _W of the weight 7.

First, as shown in FIG. 7, the outer periphery of the elastic body 8 that supports the weight 7 is fixed to the inner periphery of a cylindrical portion 107 that is continuous with the tubular body 105 via a flange portion 106.

After injecting liquid into the tube 105 and letting it stand still, the amount of displacement is applied to the weight 7 from below as shown in FIG.
Give a forced displacement of mm. Then, the amount of volume movement Vmm ³ is actually measured.

Therefore, we obtain S _W =V/l.

In this way, _SW > (S _E + S _H ) is set according to the analysis results described above.

Thus, according to the fluid-filled mount 1 of the present invention, in the high frequency vibration region exceeding secondary vibration,
The force F ₁ that attempts to push the base member 2 upward due to the suction action of the weight 7 and the force F ₂ that acts on the base member 2 via the elastic member 4 cancel each other out, so that the final The force F transmitted to the base member 2 via the orifice plate 5 can be made approximately zero. That is, dynamic magnification (｜k ^* ｜/ks)
can be made substantially zero as shown by the solid line in FIG. 13, and the vibration isolation effect in the high frequency region can be greatly improved.

Next, a second embodiment will be described based on FIG. 9.

In this embodiment, the cover plate 229 is inserted into the clamping portion 223 of the base member 202 connected by the elastic member 204 in the same manner as described above, and is closed by crimping. Then, the ring 261 holding the diaphragm 206 is inserted into the clamping part 234 at the upper end of the cylindrical part 233 of the mounting member 203 while coming into contact with the lower surface of the periphery of the disc body 235, and the clamping part 234 is crimped. Further, a communication hole 272 is provided vertically in the center of the weight 207 disposed in the cylindrical portion 233 via the sleeve 209 and the elastic body 208 to the bottom of the truncated inverted conical portion 271, and an orifice 273 is provided in the bottom wall of the communication hole 272. Open it.

In this way, the main fluid chamber 211 is located below the weight 207, which also serves as an orifice plate, and the auxiliary fluid chamber 212 is located above.
are formed respectively.

The effects of the mount 201 of the second embodiment are also substantially the same as those described above.

In the above embodiments, an upright type fluid-filled mount has been described, but an inverted type fluid-filled mount will be described below.

FIG. 10 shows an inverted type mount according to the third embodiment, in which a base member 302 is connected to a cylinder 320 having a flange piece 321 at the upper end and a clamping part 323 at the lower end, and on the flange piece 321. The mounting member 303 has a tapered hollow body 33 that expands downward and has a sufficiently larger diameter than the reverse funnel body 325.
0 and a clamping portion 33 provided at the upper end of this hollow body 330.
4 and a disc body 335 inserted into the disc body 335 and crimped.

Then, the inverted funnel body 325 of the base member 302 and the hollow body 330 of the mounting member 303 are connected by an inverted umbrella-shaped elastic member 304, and the base member 302
The diaphragm 3 is inside the clamping part 323 of the cylinder 320.
06 is inserted and crimped, and then the weight 30 is inserted into the cylindrical body 320 via the sleeve 309 and the annular elastic body 308.
Place 7. A truncated conical portion 371 having a smaller diameter than the inverted funnel 325 is provided on the upper surface of the weight 307, and the truncated conical portion 371 is located at the center of the weight 307.
A communication hole 372 is vertically provided up to the top of 1, and the communication hole 372
An orifice 373 is opened in the upper wall.

Thus, the main fluid chamber 311 is located above the weight 307, which also serves as an orifice plate, and the auxiliary fluid chamber 312 is located below.
are formed respectively.

If such an inverted type mount 301 is modeled, it will be as shown in FIG. 11, that is, the vibration transmission path is opposite to that shown in FIG. 4, which shows the upright type.

If an analysis is performed based on the model diagram of FIG. 11, in the high frequency vibration region, since x _W ≈0, the force transmitted through dk will be approximately zero. Assuming that the fluid is incompressible, S _W x _E = (S _E + S _H ) (x _E - x) to (S _W - S _E - S _H ) x _E = - (S _E + S _H ) x ∴x _E It can be expressed as =-(S _E + S _H ) x/S _W −S _E −S _H ...(iv).

On the other hand, the total transmitted force is F=kx+akx _E ...(v).

Therefore, by substituting equation (iv) into equation (v), we get F=kx{1-a(S _E +S _H )/S _W −S _E −S _H }...
(vi) is obtained.

Since this equation (iv) is the same as the equation (iii) above, it can be seen that even an inverted type can exhibit the same effect as an upright type.

Next, a fourth embodiment will be described based on FIG. 12.

The base member 402 of this embodiment has an inverted funnel portion 42.
The mounting member 403 consists of a hollow body 420 having a flange piece 424 at the lower end of a cylindrical part 423 that is continuous to the lower part of the cylinder part 423 via a tapered part 422, and a cover plate 429 joined to the flange piece 424. Third
A tapered hollow body 430 similar to the embodiment, and a cap body 4 inserted into the clamping portion 434 of the hollow body 430 and crimped.
It consists of 35. Similarly, the reverse funnel part 421 and the hollow body 430 are connected by the mounting member 404, and the ring plate 461 holding the diaphragm 406 is attached to the cap body 43 in the clamping part 434 of the hollow body 430.
5. At the same time, an orifice plate 405 having an orifice 451 in the center is inserted into the lower surface of the peripheral edge of the ring plate 461, and this clamping portion 4
Tighten 34. Furthermore, a sleeve 4 is placed inside the cylindrical portion 423.
09 and an elastic body 408, a weight 407 is disposed. This weight 407 is not provided with a communication hole or an orifice.

In this way, a main fluid chamber 411 is formed below the orifice plate 405 disposed above the weight 407, and a sub fluid chamber 412 is formed above it.

The inverted mount 401 of the fourth embodiment can also provide substantially the same effects as described above.

As is clear from the above description, according to the present invention, a chamber constituting a part of the fluid chamber is formed to bulge from the inner peripheral side of the mounting member that connects the mounting member and the base member toward the mounting member or the base member. , the weight is floatingly supported in the cross section in this chamber, and the weight is required to have the ability to contribute to fluid movement per unit relative displacement between the mounting member or base member and the weight when the fluid chamber is opened to the atmosphere. The effective area was set to be larger than the effective area of the elastic member, which is determined as the ability of the mounting member to contribute to fluid movement per unit relative displacement with the base member when the fluid chamber is opened to the atmosphere. Since the fluid-filled mount is configured, the vibration isolation effect in the high frequency range above the secondary vibration range can be greatly improved, and since this advantage can be provided with a new structure, the degree of design freedom is increased. can be achieved.

[Brief explanation of drawings]

FIG. 1 shows a first example of a fluid-filled mount according to the present invention.
A central vertical cross-sectional view showing the embodiment, FIG. 2 is a half-cut view showing its effect, and FIG. 3 is a cross-sectional view of the elastic member portion.
Figure 4 is a model diagram, Figure 5 is a vertical sectional view of the test device, Figure 6 is its working diagram, Figure 7 is a vertical sectional view of another test equipment, Figure 8 is its working diagram, and Figure 9. 10 is a similar view of the third embodiment, FIG. 11 is a model thereof, FIG. 12 is a center longitudinal sectional view of the fourth embodiment, and FIG. 13 is a central longitudinal sectional view of the second embodiment. Frequency [Hz] − dynamic magnification (|k ^* |/
ks) is a characteristic diagram. In the drawings, 1 is a fluid-filled mount, 2 is a base member, 3 is a mounting member, 4 is an elastic member, 7 is a weight, 8 is an elastic body, and 11 and 12 are fluid chambers.

Claims (1)

[Claims] 1. In a fluid-filled mount in which a mounting member connected to a vibration source and a base member on which the vibration source is mounted are joined at the inner and outer peripheries of an elastic member to form a fluid chamber inside, A mounting member or base member in which a chamber communicating with the fluid chamber is bulged toward the mounting member or base member, a weight is floatingly supported across the chamber, and the fluid chamber is opened to the atmosphere. The effective area of the weight, which is determined as the ability to contribute to the fluid movement per unit relative displacement between the weight and the weight, is calculated as the fluid movement per unit relative displacement between the mounting member and the base member when the fluid chamber is opened to the atmosphere. A fluid-filled mount characterized in that the effective area of the elastic member is set to be larger than the effective area of the elastic member required for contributing ability.