JPS6352260B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vibration isolating support device, particularly to a vibration isolating support device suitable for use as an engine mount for an automobile.

Figure 1 shows a vibration isolating support device used as a conventional automobile engine mount.
2 is an upper flange attached to the engine side, and 2 is a lower flange attached to the chassis side. These upper and lower flanges 1 and 2 are connected by a cylindrical insulator rubber 3 to form a sealed chamber between them. There is. This sealed chamber is separated into an upper chamber 6 and a lower chamber 7 by a partition plate 4 having a plurality of orifices 5 fixed to the upper flange 1, and a gap 6a is left in a part of the upper chamber 6. The upper and lower chambers 6 and 7 are filled with a fluid 8. An intermediate ring 9 is provided on the outer periphery of the central portion of the insulator rubber 3 to prevent deformation in the radial direction. This anti-vibration support device has a lower flange 2 fastened to a chassis (not shown) via stud bolts 10, and an upper flange 1 fastened to an engine (not shown) via stud bolts 11 to connect the engine and the chassis. An intervening device is placed in between.

According to this vibration isolating support device, vibration input from the engine side or the chassis side causes the insulator rubber 3 to elastically deform, resulting in a change in the volume of the lower chamber 7. Due to this change in the volume of the lower chamber 7, the lower chamber 7
The internal pressure of the lower chamber 7 increases, and the fluid in the lower chamber 7 moves to the upper chamber 6. At this time, when the fluid 8 passes through the orifice 5, a vibration damping effect is obtained by the fluid buffering.

However, in such a conventional structure, the above-mentioned damping effect is determined by the velocity of the fluid 8 passing through the orifice 5, but the diameter of the orifice 5 does not have a sufficient damping effect against low-frequency vibrations in the damping region. However, in the process of transitioning to high-frequency vibrations, the damping reaches a maximum value and then decreases, accompanied by the disadvantage of an increase in the stiffness of the dynamic spring of the vibration isolating support device. This is because as the frequency increases, the resistance for liquid to pass through the orifice gradually increases, and the amount of liquid passing through the orifice increases.
The velocity also decreases, and when the resistance to passing through the orifice becomes greater than the deformation resistance of the liquid chamber wall, the liquid chamber wall dents and accepts some of the liquid that should pass through the orifice and be removed. It is. Further, there is a problem in that the vibration transmission rate becomes large in the vibration isolation region, and the effect of reducing noise inside the vehicle is impaired. In addition, as mentioned above, the upper and lower flanges 1 and 2
Since the space is sealed, the increase in internal pressure due to the static load of the engine is added to the spring constant of the insulator rubber 3, resulting in a large spring constant as a whole, which is also a factor that impairs the anti-vibration properties. Ta.

In view of the conventional situation, the present invention forms a diaphragm in the lower chamber and sets a predetermined clearance between the diaphragm and the lower flange. By moving the fluid through the orifice to the upper chamber, a large vibration damping effect can be obtained and appropriate vibration damping characteristics can be achieved, and in the vibration isolation region of high frequency vibration, volume changes in the lower chamber are absorbed by the expansion and contraction action of the diaphragm. To suppress the movement of fluid through an orifice, thereby reducing the vibration damping effect, to reduce the spring constant as a whole to fully exhibit vibration damping characteristics, and to achieve both vibration damping characteristics and vibration damping characteristics with a simple configuration. The purpose of this invention is to provide a vibration isolating device that is capable of

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, in which the same parts as those of the conventional structure are denoted by the same reference numerals.

In the embodiment shown in FIG.
and the lower flange 2 are connected by a cylindrical insulator rubber 3 provided with an intermediate ring 9 for preventing radial deformation on the outer periphery of the central portion. Lower flange 2
has an opening 2a in the center, and a stud bolt 10
A stepped portion 21 is formed by closing the opening 2a with a retainer plate 20 or a chassis connected via a retainer plate 20 or a chassis. Here, the lower flange 2 may be made thicker in advance without providing the opening 2a as described above, and may have a stepped portion formed in the center. The inside of the cylindrical insulator rubber 3 is separated into an upper chamber 6 and a lower chamber 7 by a partition plate 4 having one or more orifices 5. Further, a diaphragm 22 is formed integrally with the insulator rubber 3 at the bottom of the lower chamber 7, and a gap 6a is left in a part of the upper chamber 6 between the lower chamber 7 and the upper chamber 6 to allow fluid 8. It is filled with. A predetermined clearance 23 is provided between the diaphragm 22 and the stepped portion 21 of the lower flange 2.
has been set. The clearance 23 is, for example, the third
As shown in the figure, there are protrusions 2 on the bottom of the diaphragm 22.
2a can be secured by integrally molding. The clearance 23 may be sufficient to allow the diaphragm 22 to expand slightly against high-frequency vibrations to be described later, and may be approximately 1 m/m or less.

Note that the lower flange 2 is formed into a flat state without forming a step as shown in FIG.
The clearance 23 may be set by integrally molding the diaphragm 22 slightly above the bottom of the insulator rubber 3.

According to the structure of the embodiment described above, in the high-frequency vibration isolation region, there is no major deformation of the insulator rubber 3, but the fluid 8 in the lower chamber 7 passes through the orifice 5 of the partition plate 4 and attempts to change its volume. There is a tendency. However, the rise in internal pressure in the lower chamber 7 quickly affects the diaphragm 22 and causes it to expand. As a result, the volume change in the lower chamber 7 is absorbed by the diaphragm 22, and the fluid 8 is prevented from flowing through the orifice 5, thereby minimizing the vibration damping effect and obtaining good vibration characteristics. It is possible.

On the other hand, in the damping region of low frequency and large amplitude, the deformation of the insulator rubber 3 is large and the diaphragm 22
Because the fluid 8 in the lower chamber 7 passes through the orifice 5 and moves toward the upper chamber 6, the volume of the lower chamber 7 changes, and at this time, the lower chamber 7 changes in volume. By passing the fluid 8 through the orifice 5, a large vibration damping effect is exhibited, and good vibration damping characteristics are obtained.

As described above, according to the present invention, in response to high-frequency vibrations, the diaphragm provided at the bottom of the lower chamber expands and contracts to absorb changes in the volume of the lower chamber and suppress fluid passage through the orifice, thereby reducing the vibration damping effect. As a result, a small spring constant can be obtained almost exclusively from the insulator rubber, which can sufficiently exhibit vibration isolation characteristics.In addition, for low frequency and large amplitude, the fluid in the lower chamber is passed through the orifice to achieve large damping. The present invention has excellent practical effects in that it is possible to exhibit the effect and obtain sufficient vibration damping characteristics, and to achieve both vibration damping characteristics and vibration damping characteristics despite the simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional device, FIG. 2 is a sectional view showing the device of the present invention, FIG. 3 is an enlarged view of the same essential parts, and FIG. 4 is a sectional view showing a different example of the present invention. . 1...Upper flange, 2...Lower flange, 3
...Insulator rubber, 4...Partition plate, 5...
...Orifice, 6...Upper chamber, 7...Lower chamber, 8
...Fluid, 22...Diaphragm, 23...Clearance.

Claims (1)

[Claims] 1. The lower flange and the upper flange are connected by a cylindrical insulator rubber, and the space inside the insulator rubber is divided into upper and lower chambers by a partition plate having an orifice, and at the bottom of the lower chamber A diaphragm is formed integrally with the insulator rubber, and the upper and lower chambers are filled with fluid leaving a gap in a part of the upper chamber, and the diaphragm and
A vibration isolating support device characterized in that a predetermined clearance is set between the lower flange or the stepped portion of the lower flange.