JPH0126410B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in fluid-filled mounts, and more particularly to a fluid-filled mount with improved isolation characteristics for high-frequency vibrations including secondary vibrations.

As shown in FIG. 3, an elastic member 230 that can elastically deform the mounting member 220 connected to the engine and the cylindrical body 211 of the base member 210 that is connected to the vehicle body frame and mounts the engine by transmitting vibrations. A fluid chamber 202 is formed by the cylindrical body 211, a partition wall 213 formed on the inner periphery of the cylindrical body 211 near the bottom, and the shear spring rubber 230, which are connected by shear spring rubber. A diaphragm 240 is attached to the lower part, thereby connecting the lower part of the cylindrical body 211 and the partition wall 213 to the diaphragm 2
40 to form a diaphragm chamber 241, and a fluid-filled engine mount 201 in which a fluid chamber 202 and a diaphragm chamber 241 are filled with a liquid or a gas such as gas is already known.

An orifice 214 is bored in the center of the partition wall 213, and the fluid chamber 202 and the diaphragm chamber 241 are communicated through the orifice 214.

By the way, without attaching a diaphragm, the partition wall 2
There is also a fluid-filled mount that is configured vertically symmetrically with reference to 13 as a boundary.

When vibration is input to the mounting member 220 of the fluid-filled engine mount 201, the force is transmitted to the cylindrical body 211 of the base member 210 via the shear spring rubber 230, and due to the flow resistance of the orifice 214 provided in the partition wall 213. Since the fluid pressure within the fluid chamber 202 fluctuates, the fluid pressure fluctuation acts on the shear spring rubber 230 and the partition wall 213, which is an orifice plate, and these forces are combined and transmitted to the base member 210.

The force acting on the shear spring rubber 230 due to fluid pressure fluctuations is
13 is larger, the dynamic magnification of the conventional fluid-filled engine mount 201 in a high frequency vibration range, for example, secondary vibration, is larger than that of an engine mount made of a single rubber material. Therefore, there is a problem in that the isolation characteristics are low in a high frequency vibration region including secondary vibrations.

Note that similar problems occur not only in engine mounts but also in fluid-filled mounts such as subframe mounts and radius arm bushings.

The present invention has been made in view of the above, and an object thereof is to provide a fluid-filled mount that can lower dynamic magnification in a high-frequency vibration region including secondary vibration and improve isolation characteristics.

In order to achieve such an object, the present invention provides a structure in which, in place of the orifice plate, a weight disposed transversely within the fluid chamber is floatingly supported by a spring means provided at least on the lower surface side of the weight. This is the summary.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a central vertical sectional view of a fluid-filled mount according to a first embodiment.

The main body of the fluid-filled mount 1 includes a base member 10 that is fixed to the vehicle body frame, a mounting member 20 that is connected to a vibration source such as an engine, and an umbrella-like elastic member that connects the base member 10 and the mounting member 20. A diaphragm 40 is attached to the base member 10.

That is, the base member 10 is made up of a mounting piece 12 formed at a suitable location on the outer periphery of a cylindrical body 11, and the mounting piece 12 has a mounting hole (not shown) drilled therein for attaching to the vehicle body frame. The lower outer periphery of an umbrella-shaped shear spring rubber that is an elastic member 30 is baked on the upper part of the cylindrical body 11, and a disk-shaped mounting member 20 is baked on the center upper part of this shear spring rubber 30, and this mounting member 20 has a cylindrical shape. body 1
1, and an engine mounting bolt (not shown) is fixed to the center of the mounting member 20 so as to protrude upward.

Further, the outer periphery of a diaphragm 40 is baked into the lower part of the cylindrical body 11 constituting the base member 10.

In this embodiment, a bracket 1 is attached to the inner circumference of the cylindrical body 11 of the base member 10 toward the center.
5 is installed horizontally, and this bracket 15 is fully extended to the center of the cylindrical body 11, and the bracket 1
A rod 16 is installed concentrically with the cylindrical body 11 on the upper surface of the tip of the rod 5.
will be established.

A thick disc-shaped weight 5 is attached to the outer periphery of the rod 16.
0 are loosely attached in the center, and at this time, the weight 50
A coil spring 51 is stretched around the outer periphery of the rod 16 between the lower surface and the bracket 15, and a weight 5
Flange 1 formed on the upper surface of 0 and the upper end of rod 16
There is also a coil spring 52 on the outer periphery of the rod 16 between 7.
hang it up. As a result, the weight 50 is floatingly supported in a transverse manner within the cylindrical body 11 constituting the fluid chamber 2.

A gap C is formed between the outer circumference of the weight 50 and the inner circumference of the cylindrical body 11.

In this way, the fluid-filled mount 1 is connected to the fluid chamber 2 above by the floating weight 50.
The lower part is defined by a diaphragm chamber 41, and the fluid chamber 2 and the diaphragm chamber 41 are communicated through a gap C formed between the outer periphery of the weight 50 and the inner periphery of the cylindrical body 11.

The fluid chamber 2 and diaphragm chamber 41 of the fluid-filled mount 1 configured as described above are filled and sealed with a fluid such as liquid or gas, so that the mounting member 20 faces above the cylindrical body 11 in a free state. Meanwhile, the weight 50 is in the neutral position.

Next, the operation of the fluid-filled mount 1 constructed as above will be described.

First, when high-frequency vibrations including secondary vibrations in which fluid does not pass through the gap C between the weight 50 and the cylindrical body 11 are input to the mounting member 20, the weight 50
Although the weight 50 moves up and down against the elastic force of the weights 1 and 52, in the high frequency range, the weight 50 remains almost stationary due to inertia. The force on 10 will be small.

In this case, the shape of the shear spring rubber 30 is determined by the force acting on the base member 10 via the shear spring rubber 30 due to pressure fluctuations in the fluid chamber 2, and the relative position of the mounting member 20 and the base member 10. If the setting is made so that the force generated by the change in is balanced, the dynamic magnification in the high frequency vibration region can be made extremely low, and the cutoff characteristics can therefore be extremely excellent.

Therefore, if we express the frequency-dynamic magnification characteristic diagram, we get the second
As shown in the figure.

In FIG. 2, the solid line shows the characteristics of the fluid-filled mount of the present invention, and the broken line shows the characteristics of the mount made of a single rubber material.

As is clear from the above description, according to the present invention,
Instead of the conventional fixed orifice plate, the weight is floatingly supported across the fluid chamber, so the weight floats up and down within the fluid chamber, lowering the dynamic magnification in the high frequency vibration region including secondary vibration. It is possible to achieve an improvement in the vibration isolation characteristics.

[Brief explanation of drawings]

FIG. 1 is a central vertical cross-sectional view showing an embodiment of a fluid-filled mount according to the present invention, FIG. 2 is a frequency-dynamic magnification characteristic diagram, and FIG. 3 is a central vertical cross-sectional view of a conventional fluid-filled mount. . In the drawing, 1 is a fluid-filled mount, 2 and 41 are fluid chambers, 10 is a base member, 20 is a mounting member, and 30
is an elastic member, and 50 is a weight.

Claims (1)

[Claims] 1 A mounting member connected to a vibration source and a base member on which the vibration source is mounted are connected by an elastic member that can be elastically deformed by transmission of vibration to form a chamber therein, and a fluid is sealed in the chamber. A fluid-filled mount, characterized in that a weight disposed transversely within a fluid chamber is supported in a floating manner by a spring means provided at least on the lower surface of the weight.