JPS6113043A - Vibrationproof apparatus - Google Patents

Abstract

PURPOSE:To absorb vibration by inserting a pipe having a small effective area into a hollow chamber and installing a rotary body which is revolved by the flow of the fluid in the pipe and properly generating resonance having an arbitrary frequency even in the case when the axial length of the pipe member is short. CONSTITUTION:One edge of a pipe member 22 is inserted into a base plate 12, and the other edge of the pipe member 22 is opened to the atmosphere. A rotary body 24 is arranged inside the pipe member 22 so as to be shifted in the longitudinal direction of the pipe member 22. The shift amount in the longitudinal direction of the rotary body 24 is regulated by the stoppers 25A and 25B projecting in the direction for reducing the inside diameter towards the inside of the pipe member 22. With such constitution, vibration is applied onto an elastic member 16 through a top plate 14, and gas-column resonance is generated on the pipe member 22, and said vibration can be effectively absorbed by the rotary body 24.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a vibration isolator for reducing vibrations from a vibration source.

[Background Art] Vibration isolating devices, generally called vibration isolating rubber, are used, for example, in engine mounts of automobiles to absorb vibrations from the automobile engine and prevent them from being transmitted to the vehicle body.

As this vibration isolator, a structure has been proposed in which a fluid is sealed in a hollow chamber of a vibration absorbing body mainly made of a hollow molded body of an elastic material, and a tubular part is connected to this hollow chamber. In this vibration isolator, vibrations applied to the hollow chamber cause so-called air column resonance in the tubular portion, thereby making it possible to obtain large vibration damping.

In this vibration isolator, since the mass of the fluid within the tubular portion affects the resonance frequency, the length of the tubular portion must be significantly increased in order to obtain desired damping characteristics. Particularly when air is used as the resonant fluid, this resistance becomes large, which increases pipe friction and becomes a cause of limiting the occurrence of resonance.

[Object of the Invention 1] Taking the above-mentioned facts into consideration, the object of the present invention is to obtain a vibration isolating device that can shorten the length of the pipe material communicating with the hollow chamber.

[Summary of the Invention] In the vibration isolating device according to the present invention, a tube with a small effective area communicates with a hollow chamber, and a rotating body is provided that rotates due to movement of fluid within the tube.

Therefore, the rotating body rotates as the hollow chamber expands and contracts, and in this case, resonance occurs due to inertia in the rotational direction, making it possible to obtain large damping.

[Embodiments of the Invention] FIG. 1 shows a cross-sectional view of a vibration isolator IO to which the present invention is applied.

In this vibration isolating device 10, a cylindrical elastic body 16 is vulcanized and bonded between a base plate 12 and a top plate 14, and constitutes a vibration absorbing body. A hollow chamber 18 surrounded by the base plate 12, top plate 14, and elastic body 16 is an air chamber.

The base plate 12 is fixed to the body of an automobile (not shown), and is provided with a mounting plate 20 erected on the top plate 14.
An automobile engine (not shown) is mounted on the top plate 14 via the top plate 14.

One end of a tube 22 is communicated with the base plate 12, and the other end of the tube 22 is open to the atmosphere. Further, a rotating body 24 is disposed inside the tube 22, and is movable in the longitudinal direction of the tube 22.

The amount of movement in the longitudinal direction of the rotating body 24 is determined by the stoppers 25A, 25 that protrude into the inside of the tube 22 in the direction of reducing the inner diameter.
Until it comes into contact with B.

As shown in FIG. 2, the rotating body 24 is a cylindrical block (
It has a configuration in which a spiral groove 24A is carved on the outer periphery of the material (resin, metal, etc.).

The longitudinal dimensions of the stoppers 25A and 25B are those of the rotating body 24.
It is longer than the resonance amplitude of .

In the vibration isolator 10 of this embodiment configured as described above, vibrations generated in the engine are applied to the elastic body 16 via the top plate 14, causing air column resonance inside the tube material 22,
This vibration can be effectively absorbed.

In particular, in this embodiment, the mass inside the tube material 22 is the mass of air m
1 and the mass m2 of the rotating body 24, and due to the inertia during reciprocation of the rotating body 24 and rotation due to air circulation in the spiral groove 24A, when the diameter of the tube material 22 is relatively large and the longitudinal dimension is short, can also reliably generate resonance.

Therefore, by increasing the inner diameter of the tube 22, it is possible to reduce the pressure loss that occurs when air enters and exits the tube 22. In particular, this pressure loss has a large influence because it is inversely proportional to the square of the cross-sectional area of the pipe material 22.

Furthermore, since the longitudinal dimension of the tube material 22 can be shortened, the tube friction resistance, which is proportional to the length of the tube material 22, can be reduced, and the adverse effects of resonance generation can be eliminated.

Note that the stoppers 25A and 25B in this embodiment are
4 is not necessary if there is no risk of it jumping out from the tube material 22, and the bent portion of the tube material 22 may be used as a substantial stopper. Furthermore, the tube material 22 is not limited to a straight shape, but may be bent in a spiral shape or the like.

FIG. 3 shows a vibration isolator according to a second embodiment of the present invention.

In this embodiment, the upper end of a cylindrical cover 40 is fixed to the base plate 12 of the first embodiment, and the upper end of a bottomed cylindrical cover 42 is attached to the lower end of this cylindrical cover 40. It has a fixed structure. These cylindrical covers 4
The peripheral edge of a diaphragm 44 is sandwiched between the bottomed cylindrical cover 42, and the base plate I.12, the cylindrical cover 40, and the diaphragm 44 form a hollow chamber 46.

A liquid is sealed in the hollow chamber 46 and the hollow chamber 18, and one end of a tube member 48 is fixed to the base plate 12 to communicate the hollow chamber 18 and the hollow chamber 46.

The rotating body 24 is also arranged within this tube member 48 as in the previous embodiment.

The lower end of this tube 48 is bent in the axial direction to form a stopper 48A, and the hollow chamber 18.4 of the base plate 12
The periphery of the opening that communicates with the pipe member 6 protrudes inward from the inner diameter of the tube member 48 and serves as a stopper 48B. In this embodiment, these stoppers 48A and 48B are close to the axial ends of the rotating body 24, and almost eliminate axial movement of the rotating body 24. Therefore, in this embodiment, the rotating body 24 rotates without reciprocating when the top plays 1 and 14 vibrate up and down, and the inertia during this rotation causes resonance within the tube 48.

It goes without saying that the rotary body 24 whose movement in the axial direction is restricted as in this embodiment can be applied to the tube member 22 in which air flows, as in the previous embodiment.

An air chamber 50 is formed between the diaphragm 44 and the bottomed cylindrical cover 42, and a mounting port 52 protrudes from the lower end of the bottomed cylindrical cover 42 for attachment to the vehicle body.

FIG. 4 shows a rotating body 24 used in a third embodiment of the present invention. The rotating body 24 of this embodiment also has a spiral groove 24A carved on the outer periphery as in the previous embodiments, but the tube material 5
A plurality of poles 56 are held in the spiral groove 2.
It has entered 4A. The outer diameter of these poles 56 is larger than the inner diameter of the spiral groove 24A, and they are in point contact with the rotating body 24.

Therefore, these poles 56 constitute bearings for the rotating body 24, and the rotating body 24 absorbs vibrations due to inertia when fluid flows within the tube member 54, as in the previous embodiment.

Next, FIGS. 5 and 6 show a rotating body 24 used in a fourth embodiment of the present invention. The rotating body 24 of this embodiment has sharp points formed at both ends in the axial direction, and these sharp points are connected to the stopper 6.
0A, 60B (7) are abutted against the small hole 62 and supported pivotally. These stoppers 60A and 60B are attached to a tube 64 similar to those in the previous embodiments, and vibrations are absorbed by the inertia of the rotating body 24 when fluid flows within the tube 64.

Next, FIGS. 7 and 8 show the rotating body 2 used in the fifth embodiment of the present invention.
4 is shown. In this embodiment, the mounting structure is the same as in the previous embodiment, but the rotating body is shaped like a three-blade propeller. Therefore, in this embodiment as well, vibrations are absorbed by the inertia of the rotating body 24.

[Effects of the Invention] As explained above, in the vibration isolating device according to the present invention, a tube with a small effective area is connected to the hollow chamber, and a rotating body that rotates due to the movement of fluid in this tube is provided, so that the axial length of the tube material can be reduced. Even when the distance is short, it has an excellent effect of being able to appropriately generate resonance at any frequency and absorb vibrations.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a first embodiment of a vibration isolator according to the present invention, FIG. 2 is a perspective view showing a rotating body, FIG. 3 is a sectional view showing a second embodiment of the present invention, and FIG. The figure is a sectional view showing the rotating body etc. used in the third embodiment of the present invention, FIG. 5 is a sectional view showing the rotating body etc. used in the fourth embodiment of the present invention, and FIG. 6 is a side view of FIG. 5. , FIG. 7 is a sectional view showing a rotating body etc. used in the fifth embodiment of the present invention, and FIG. 8 is a side view of FIG. 7. DESCRIPTION OF SYMBOLS 10... Vibration isolator, 16... Elastic body, 22.48, 54.64-... Pipe material, 24... Rotating body. Agent Patent Attorney Atsushi Nakajima Figure 1 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] (1) A fluid is sealed in a vibration-absorbing hollow chamber mainly made of a hollow molded body of an elastic material, a tube with a small effective area is communicated with the hollow chamber, and a rotating body is created which rotates due to the movement of the fluid inside the tube. A vibration isolating device characterized by being provided with.