JPS6337542Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention particularly relates to a vibration-proof mount for mounting an automobile engine to a vehicle body in a vibration-proof manner.

The vibrations that propagate to the car body include low-frequency vibrations caused by the vehicle running on the road and high-frequency vibrations caused by the high-speed rotation of the engine, and anti-vibration mounts that can absorb both types of vibrations. preferable.

In particular, engines vibrate vertically, longitudinally, horizontally, and horizontally, which not only causes discomfort to the passengers, but also causes problems such as the vibration noise being stuck inside the vehicle. The engine is fixed to the vehicle body.

A conventionally widely used anti-vibration mount has a structure as shown in Fig. 3, in which an anti-vibration rubber 3' is interposed between an engine-side mounting bracket 1' and a member-side mounting bracket 2'. It is known that anti-vibration rubber functions to damp vibrations and achieves its intended purpose.

However, when accelerating and decelerating a car, especially when the engine speed is in the range of 3,000 to 4,500 revolutions per minute, it is impossible to prevent engine transmission sound from being generated and transmitted to the interior of the car as abnormal noise.

This noise is caused by high-order components of about 300Hz to 600Hz, and this type of vibration isolation mount cannot exhibit a vibration isolation function against the noise.

Therefore, the present invention proposes a vibration-isolating mount that not only sufficiently exhibits the vibration-isolating function against the above-mentioned high-order components, but also has high vibration-isolating properties against low-frequency vibrations and muffled sounds (100 to 140 Hz). In particular, a cylindrical anti-vibration rubber in which a mass damper is integrally interposed in the middle part of the cylindrical body is disposed between the upper and lower metal fittings, and the top surface is placed between the upper metal fitting and the bottom circumference. By joining the surfaces to the lower metal fittings in an airtight manner,
An air chamber surrounded by anti-vibration rubber and a lower fitting forms an air chamber whose volume can be changed, while a rubber piston-like body integrally connected to the upper fitting by a shaft passing through the anti-vibration rubber vertically in an airtight manner is disposed within the air chamber. In addition to partitioning the air chamber into two upper and lower chambers, an orifice is provided to communicate between the upper and lower chambers and the atmosphere, thereby making it possible for air to flow in and out in an amount corresponding to volume changes elastically. By providing a pressure reducing diaphragm in relation to at least one of the upper and lower chambers, the structure is characterized in that the effective volume change can be reduced by a certain amount, and thus the annular mass damper can reduce the amount of higher-order components. It resonates with vibrations, lowering the vibration transmission rate to the member side, and lowering the level of engine transmitted sound inside the vehicle.On the other hand, the orifice exhibits sufficient damping function, especially against low-frequency vibrations, and is further muffled by the pressure-reducing diaphragm. The dynamic spring constant for sound has been reduced, thus making it possible to effectively interrupt vibration transmission over the entire vibration range from low to high frequencies.

The content of the present invention will be explained in detail below with reference to the accompanying drawings.

The vibration-isolating mount shown in FIG. 1 is composed of an upper metal fitting 1, a lower metal fitting 2, a vibration-isolating rubber 3 which is a cylindrical body with a top and has a mass damper 11, a rubber piston-like body 4, and a pressure reducing diaphragm 8 as its main components.

The upper metal fitting 1 is an upper seat for fixing the engine, while the lower metal fitting 2 is a lower seat for fixing it to a frame such as a vehicle body.

It should be noted that the mounting form can of course be reversed.

The anti-vibration rubber 3 has a cylindrical shape with a top, and a mass damper 11 is integrally interposed in the middle of the cylindrical body.The top surface is connected to the lower surface of the upper metal fitting 1, and the bottom circumferential surface is connected to the upper surface of the lower metal fitting 2. The two are airtightly connected to each other.

Through this connection, the vibration isolating rubber 3 and the lower metal fitting 2
and forms an air chamber 9 whose volume can be changed.

Next, the rubber piston-like body 4 is made of rubber and formed into a block having an appropriate shape, and is integrally connected to the upper metal fitting 1 by a shaft 5 that passes through the vibration-proof rubber 3 in an airtight manner in the vertical direction. , is installed horizontally within the air chamber 9, and partitions the air chamber into two chambers, an upper chamber 9a and a lower chamber 9b.

On the other hand, the decompression diaphragm 8 is flexible in case of minute deformation or a diaphragm in which there is a plate at a certain distance from both sides of a flexible membrane or rubber membrane, etc., for restricting the range of movement of this membrane.
A vacuum diaphragm made of a membrane, such as a corded rubber membrane, which becomes difficult to deform due to the sudden increase in tension when the deformation exceeds a certain amount is suitable.

This pressure reducing diaphragm 8 is connected to both upper and lower chambers 9a, 9.
b, and the illustrated example is arranged along the bottom surface of the lower fitting 2, and the upper small chamber separated by the membrane is connected to the lower chamber 9b. The chambers on the lower side communicate with the atmosphere.

This pressure reducing diaphragm 8 may be provided in a single unit having a structure capable of effecting a predetermined amount of volume change, or a plurality of units may be provided in a distributed manner so that their total capacity corresponds to the predetermined volume change, and the number of units to be provided may be selected as appropriate.

Thus, 10a and 10b are orifices formed in the vibration isolating rubber 3 and the lower metal fitting 2, respectively, and the orifice 10a penetrates the wall of the vibration isolating rubber 3 surrounding the upper chamber 9a and opens to the atmosphere. On the other hand, the orifice 10b is provided so as to pass through the lower fitting 2 surrounding the lower chamber 9b and open to the atmosphere, so that when the volume of each chamber 9a, 9b changes, a corresponding amount of air is elastically released. It is becoming more and more common to have inflows and outflows.

The structure of the anti-vibration mount is as described above, and the mass damper 11 interposed in the anti-vibration rubber 3
is made of a metal material, and is arranged in such a manner that the rubber cylinder body of the vibration isolating rubber 3 is separated into upper and lower parts, and is interposed all at once during the vulcanization molding of the vibration isolating rubber, thereby making it strong. You can get something that is integrated with.

Note that the mass damper 11 shown in the first figure has an annular shape.

Considering the case where the engine is attached to the vehicle body through the vibration-proof mount having the structure described above, when the vibration-proof mount vibrates due to engine drive and receives dynamic compression deflection, the behavior of the air chambers 9a and 9b is as follows. The vibration is alleviated by the influence of the spring constant, which is the sum of the dynamic spring constant due to the air and the dynamic spring constant due to the rubber support of the vibration isolating rubber 3 and the rubber piston-like body 4, and the damping coefficient due to the air. As a result, it exhibits anti-vibration function.

Furthermore, it is possible to attenuate vibrations by the throttling action of the orifices 10a and 10b, and together with the cushioning performance provided by the air springs, the vibration damping effect can be enhanced.

In addition, the mass damper 11 resonates with vibrations in a certain frequency range, thereby alleviating vibration transmission to the vehicle body (member) side.

Moreover, this anti-vibration mount has a pressure reducing diaphragm 8.
By providing a (around hertz)
It is possible to prevent the internal pressure of the air chambers 9a and 9b from increasing excessively in response to the generation of muffled noise, and thus the dynamic spring constant can be reduced on the high frequency vibration side, and the vibration can be adjusted from the low frequency range to the high frequency range. Vibration transmission can be effectively blocked over a wide area.

By the way, the mass damper 11 provided on the anti-vibration rubber 3
is a member that is interposed to provide a damper function with respect to vibration propagation in the compression direction to the vibration isolating rubber 3, but on the other hand, the vibration isolating mount itself is designed to maintain a large spring constant against vibrations in the shear direction. It also has the function of

Therefore, in order to set the resonance frequency of the mass damper 11 to, for example, 350 Hz for vibrations in the rubber compression direction, and to set the resonance frequency to 150 Hz for vibrations in the shear direction, the weight and shape of the mass damper 11 are appropriately selected. In this way, it exhibits an absorption function for the engine transmitted sound of about 300 to 600 Hz that is likely to occur during acceleration and deceleration, and also
It has a blocking function against abnormal noise caused by stopper interference caused by rolling vibrations that tend to occur when starting an engine, etc., and plays an important role in making the inside of a car quieter.

Next, the embodiment shown in FIG. 2 is another embodiment, and has the same structure as the embodiment shown in FIG. 1 except that the form of the mass damper 11 is changed. Therefore, the mass damper 11 will be explained below.

The mass damper 11 according to the illustrated example is made of one thick plate, and has a flat bottom part 11a in the central part parallel to both the metal fittings 1 and 2, and one of the mounting metal fittings, e.g. It is formed into a deep dish-like curved body having a peripheral edge portion 11b that is bent and extended so as to gradually approach the metal fitting 1, and further has a flat bottom portion 11a.
It has a hole in the center thereof into which the shaft 5 can be loosely inserted.

The mass damper 11 having the above-described structure has a flat bottom part 11a and a peripheral part 11b for vibration in the compression direction.
All of them exhibit a vibration absorbing effect, and in particular, the peripheral edge portion 11b can increase the dynamic spring constant of the vibration isolating rubber 3 and exhibit vibration isolating properties more markedly against vibrations in the shear direction.

The present invention has the structure and function described above, and has the spring characteristics of the vibration isolating rubber 3 and the air chamber 9.
As a result of the synergistic action of the spring characteristics of the air springs exhibited by a and 9b, the vibration damping effect is extremely large.

Furthermore, by providing the pressure reducing diaphragm 8, it is possible to suppress the pressure increase in the air chamber due to high frequency vibrations and reduce the dynamic spring constant, which can relatively increase the dynamic spring constant against low frequency vibrations. Therefore, transmission of vibration can be effectively cut off in all frequency ranges.

In addition, the mass damper 11 operates in the intermediate frequency range (100
~150Hz) and high frequency range (300~500Hz).
Hz), it exhibits an even greater vibration damping and cutting effect against transmitted sound.

Therefore, the mount of this invention reduces vibrations caused by high-speed engine rotation while driving, as well as during startup.
It can provide sufficient anti-vibration function against special noises that occur during acceleration and deceleration.

[Brief explanation of the drawing]

FIGS. 1 and 2 are longitudinal sectional front views of various examples of the vibration isolating mount of the present invention, and FIG. 3 is a longitudinal sectional front view of a conventional anti-vibration mount. 1... Upper metal fitting, 2... Lower metal fitting, 3... Anti-vibration rubber, 4... Rubber piston-like body, 5... Shaft, 8...
Decompression diaphragm, 9...air chamber, 9a...upper chamber, 9b...lower chamber, 10a, 10b...orifice, 11...mass damper.

Claims (1)

[Scope of utility model registration request] A mass damper is integrally interposed in the middle of the cylinder body, and a vibration-proof rubber in the shape of a capped cylinder is arranged between the upper and lower metal fittings, with the top surface serving as the upper metal fitting and the bottom peripheral surface serving as the lower metal fitting. By being airtightly connected, an air chamber surrounded by the vibration isolating rubber and the lower metal fitting and whose volume can be changed is formed, while being integrally connected to the upper metal fitting by a shaft passing through the vibration isolating rubber vertically in an airtight manner. By disposing a rubber piston-like body in the air chamber to partition the air chamber into two upper and lower chambers, and by providing an orifice in communication between the upper and lower chambers and the atmosphere,
By making it possible to elastically allow air to flow in and out in an amount corresponding to the volume change, and by further providing a pressure reducing diaphragm in relation to at least one of the upper and lower chambers, it is possible to reduce the effective volume change by a certain amount. Anti-vibration mount with air damping for engines.