JPH01255735A - Fluid-sealed type vibration isolating mount - Google Patents

Abstract

PURPOSE:To enable a good vibration isolating effect to be produced over a wide frequency region by making sealed fluid flow between a first fluid chamber and a second fluid chamber through communicating holes and an intermediate chamber. CONSTITUTION:The space between a first supporting body 10 and a second supporting body 12 is elastically connected by a rubber elastic body 14. On both sides interposing a plurality of partition plates 38, a first and a second fluid chambers 42, 44 are formed. Between the partition plates 38, an intermediate chamber 48 of a prescribed volume is defined. When vibration is input between the first supporting body 10 and the second supporting body 12, based on the variation of internal pressure inside the first fluid chamber 42, the flow of sealed fluid is caused between the fluid chambers 42 and 44 through communicating holes 50 and an intermediate chamber 48. Thus, a good vibration isolating effect can be produced over a wide frequency region.

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a fluid-filled vibration-isolating mount, and in particular, a fluid-filled vibration-isolating mount that exhibits excellent vibration-isolating characteristics over a wide frequency range, with a simple structure. The present invention relates to technology that can be advantageously realized.

(Prior Art) Conventionally, Japanese Patent Publication No. 48-36151 and Japanese Unexamined Patent Application Publication No. 1983-1988 have been used as a type of vibration-proof connecting body that is interposed between two members constituting a vibration transmission system and connects these members in a vibration-proof manner. -107
No. 142, JP-A No. 61-274131, etc., a first support body and a second support body are arranged at a predetermined distance from each other and are interposed between them. A connecting body is formed by elastically connecting with a rubber elastic body, and a fluid storage chamber in which a predetermined incompressible fluid is sealed is formed inside the connecting body. A partition member is provided, and first and second fluid chambers are defined on both sides of the partition member, in which a relative fluid pressure difference is generated when vibration is input, and the first and second fluid chambers are defined on both sides of the partition member. A structure with a communication channel that communicates the chambers with each other.
A so-called fluid-filled anti-vibration mount is known.

In other words, in such a vibration-proof mount, the flow effect or liquid column resonance based on the flow of fluid through the communication channel between the first and second fluid chambers is caused when vibration is input. Due to this action, a predetermined vibration damping effect set in the communication channel can be exerted.

However, in a vibration isolation mount with such a structure, the vibration isolation effect based on the liquid column resonance of the fluid flowing through the communication channel is limited to a relatively narrow area near the resonance point of the liquid column mass set in the fluid channel. While this effect is noticeable in response to input vibrations in the frequency range, when vibrations are input in an even higher frequency range, the cough communication flow path becomes substantially obstructed, resulting in a significant increase in the mount dynamic spring constant. This caused the problem that the anti-vibration function actually deteriorated.

In addition, in order to cope with such a high movement spring of the mount r,
An open communication channel is provided between the fluid chambers in parallel to the main communication channel, and the main communication channel is brought into a closed state by the liquid column resonance of the fluid flowing through the open communication channel. It may be possible to reduce the mount dynamic spring constant when vibration is input in a high frequency range, but in such a case, it is necessary to provide separate main communication channels and open communication channels. In addition, in order to prevent the flow of fluid through the free passage when vibrations are input in the low frequency range, such a free passage is disclosed, for example, in Japanese Patent Application Laid-Open No. 57-9340. It is necessary to arrange a movable plate or the like within the flow path, which has the inherent problem of complicating the structure and increasing manufacturing costs.

(Problem to be solved) Here, the present invention has been made against the background of the above-mentioned circumstances, and the problem to be solved is:
The remarkable rise of the mount moving spring when inputting vibrations in a high frequency range can be eliminated, and the excellent vibration damping effect based on the flow effect of the fluid sealed inside or the liquid column resonance effect can be achieved by inputting vibrations in a wide frequency range. To provide a fluid-filled vibration-proofing mount that can exhibit good performance against various conditions, with a simple structure and at low cost.

(Solution Means) In order to solve such problems, the present invention includes a first support and a second support that are arranged at a predetermined distance from each other and are interposed between them. a fluid storage chamber having a predetermined incompressible fluid sealed therein is formed between the first support body and the second support body; A plurality of rigid partition plates are arranged facing each other at a predetermined interval in the fluid storage chamber, and first and second partition plates are arranged so that a relative fluid pressure difference is generated on both sides of the plurality of partition plates when vibration is input. a second fluid chamber, an intermediate chamber of a predetermined volume is defined between the partition plates, and the first and second fluid chambers are connected to each of the partition plates through the intermediate chamber. The fluid-filled vibration damping mount is characterized by a fluid-filled vibration damping mount in which communication holes are formed in opposing directions of the partition plates so that at least a portion thereof overlaps with each other.

(Examples) Hereinafter, in order to clarify the present invention more specifically, examples of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 shows an example of an automobile engine mount to which the present invention is applied. In this figure, 10 and 12 are first and second support fittings as first and second supports, respectively, and are arranged at a predetermined distance from each other. Further, a rubber elastic body 14 is interposed between the first support body 10 and the second support body I2, and the first support body 10 is bent by the rubber elastic body 14. and the second support 12 are integrally and elastically connected to each other.

In the engine mount in this embodiment, the first support IO and the second support 12 are attached to the engine unit side and the vehicle body side, respectively, so that the engine unit is attached to the vehicle body. It is designed to provide anti-vibration support.

More specifically, the first support fitting 10 is formed in a substantially truncated conical shape, and has a mounting bolt 16 protruding in the axial direction at the center of its large-diameter end surface. It is fixed to the engine unit side using the mounting pin 16.

On the other hand, the second support fitting 12 has two cylindrical fittings 20 and 22 each having a mounting part 18 expanding in the shape of an outer flange at one end in the axial direction. The mounting portion 18.1 is constructed by being concentrically superimposed on each other in the axial direction while in contact with each other and integrated by welding or the like.
It is fixed to the vehicle body side by bolts or the like inserted into a plurality of mounting holes 24 provided at the overlapping portion of the parts 8 and 8.

The second support fitting 12 is arranged concentrically with respect to the first support fitting 10 at a predetermined distance in the axial direction. Further, among the cylindrical metal fittings 20.22 constituting the second support metal fitting 12, in the cylindrical metal fitting 20 located on the first support metal fitting 10 side, the cylindrical portion 26 is The diameter of the cylindrical portion 26 is tapered outward, and the inner circumferential surface of the cylindrical portion 26 is approximately parallel to the outer circumferential surface of the first support fitting 10, with both surfaces separated by a predetermined distance. They are separated and facing each other.

Further, the rubber elastic body 14 is interposed between the facing surfaces of the outer circumferential surface of the first supporting metal fitting 10 and the inner circumferential surface of the cylindrical metal fitting 20 constituting the second supporting metal fitting 12. This rubber elastic body 14 has a substantially truncated conical shape, and
The interior thereof has a cavity 28 that opens to the large diameter side end face, and the small diameter side end face is formed on the outer circumferential surface of the first support fitting 10, and the large diameter side outer circumferential edge is formed on the inner surface of the cylindrical metal fitting 20. The first and second support fittings 10.12 are elastically connected to each other by being vulcanized and bonded to the peripheral surfaces, respectively.

On the other hand, in the other cylindrical metal fitting 22 constituting the second support metal fitting 12, the cylindrical portion 30 is
It is formed with an inner diameter that is a predetermined dimension larger than the inner diameter on the small diameter side of the cylindrical portion 26 at 0, and a caulked portion 32 is provided at the end in the axial direction.

A partition member 34 and an elastic closure body 36 are respectively fitted into the cylindrical portion 30 of the cylindrical metal fitting 22 in a state where they are overlapped with each other. Here, the partition member 34 is made of a rigid material such as metal and has an approximately disk shape as a whole, while the elastic closure body 36 is made of a predetermined rubber material and has an approximately thick disk shape. It is formed. And these partition members 34
The elastic closure body 36 is held by having the outer circumferential edges overlapped with each other compressed in the axial direction between the axial end surface of the cylindrical metal fitting 20 and the caulking portion 32 of the cylindrical metal fitting 22. A cylindrical metal sleeve 40 is embedded in the outer peripheral portion of the elastic closure 36, so that the cylindrical metal sleeve 20 and the caulking portion 32 can be held with sufficient clamping force. is being used.

In other words, the opening of the cylindrical metal fitting 22 is fluid-tightly closed by the elastic closing body 36, whereby the elastic closing body 3
A fluid storage chamber is formed between 6 and the rubber elastic body 14, and the partition member 34 partitions the fluid storage chamber in a direction perpendicular to the mount axis. 34, a first fluid chamber 42 is defined on the rubber elastic body 14 side, and a second fluid chamber 44 is defined on the elastic closure body 36 side. When vibration is input between the first and second support fittings 10.12, the first fluid chamber 42
The second fluid chamber 44 serves as a pressure receiving chamber whose internal pressure is changed based on the elastic displacement of the rubber elastic body 140.
The elastic closure bodies 36 are relatively easy to deform, and are configured as equilibrium chambers in which changes in internal pressure are avoided based on the elastic deformation.

On the other hand, the first fluid chamber 42 and the twenty fluid chamber 44
The partition member 34 that partitions the two is constructed by concentrically overlapping disk-shaped partition plates 38 and 38, each made of a rigid plate with a predetermined thickness. Further, on the overlapping surface of each partition plate 38, an annular spacer part 46 that protrudes at a predetermined height in the axial direction at the outer peripheral edge is integrally provided. Partition plates 38.38 are disposed parallel to each other at a predetermined distance in the axial direction, so that between the side partition plates 38.38, there is a space independent from the first and second fluid chambers 42.44. An intermediate chamber 48 of a predetermined volume is defined.

Furthermore, each of these partition plates 38 is provided with a communicating hole 50 having a circular hole shape of a predetermined diameter in the center, and the inside of the intermediate chamber 48 is connected to one of the communicating holes. 50 into the first fluid chamber 42, and through the other communication hole 50 into the second fluid chamber 44, respectively. Here, as is clear from FIG. 1, these two communication holes 50.50 are formed on the same axis, and in the opposing direction of the partition plates 38.38, that is, in this embodiment. , are formed in a form that substantially completely overlaps in the mount axis direction which is the main vibration input direction.

Therefore, in the engine mount having such a structure, when vibration is input between the first support fitting 10 and the second support fitting 12, the internal pressure in the first fluid chamber 42 decreases. Based on the variation, the first fluid chamber 42 and the second fluid chamber 4
4, the sealed fluid flows through the communication hole 50, the intermediate chamber 48, and the communication hole 50.

Here, the inventors conducted experiments and studies, and found that the vibration isolation effect of an engine mount with such a structure is particularly superior to that of a conventional structure with a single communication flow path system. It has become clear that this material exhibits extremely characteristic frequency characteristics compared to other materials, and based on this knowledge, the present invention has been completed.

Specifically, an engine mount with the above-mentioned structure exhibits vibration isolation characteristics as shown in Figure 2, and as is clear from this figure, this engine mount has two Point that can be considered as liquid column resonance point: f
l and r2 are recognized.

After considering such phenomena, we found that
As shown in FIG. 3, the inner diameter of the communication hole 50 provided in each partition plate 38 is defined as t, the thickness of the partition plate 38 is defined as t, and the distance between the outer surfaces of the two partition plates 38 and 38 is If is l, then at the first resonance point: fl, inner diameter = D, length =
On the other hand, when the communication channel having a circular cross section of 1 is considered as a communication channel that communicates the first and second fluid chambers 42, 44, the resonance frequency of the liquid column is approximately equal to the resonance frequency of the second fluid chamber 42, 44. At the resonance point f2, the inner diameter is D, the length is a communication channel having a circular cross section, that is, the communication hole 50 in one partition plate 38, and the first and second fluid chambers 42 and 44. It has become clear that when considered as a communication flow path, the resonance frequency of the liquid column is almost the same.

Therefore, in the engine mount in this embodiment, by appropriately setting the first and second resonance points: fl, [2, the input vibration in the frequency range near the first resonance point: r1 is reduced. On the other hand, a predetermined vibration isolation effect based on the liquid column resonance action can be exhibited, and the rise of the mount moving spring when vibration is input in a higher frequency range is caused by the existence of a second resonance point 2f2. Therefore, the vibration can be effectively suppressed by the liquid column resonance effect, and an excellent vibration damping effect can be exhibited against input vibration over a wide frequency range. In addition, in FIG. 2, the first fluid chamber (42) and the second fluid chamber (44) have a thickness of
An engine with a conventional structure, in which the engine is partitioned by a partition member (34) made of a single plate material of l, and a communication flow path having a circular cross section with an inner diameter of D is provided to the partition member. The vibration isolation characteristics of the mount will also be shown as a comparative example.

Furthermore, in such an engine mount, there is no need to provide a reaching channel or a movable plate, and the structure is extremely simple, so that the excellent vibration isolation performance as described above can be exhibited. It also has the advantage that the mounting device can be provided at low cost and with good manufacturability and ease of assembly.

By the way, as is clear from the above considerations, the setting of the first resonance frequency: fl is based on the inner diameter of the communication hole 50 = D and the distance between the outer surfaces of the partition plates 38 and 38: l (arrangement interval: T). By adjusting the second resonance frequency: r2, the inner diameter of the communication hole 50 = D and the thickness of the partition plate 38:
This can be done by adjusting t.

For example, in this embodiment, by setting the first resonant frequency fl to approximately 10 to 30 Hz and the second resonant frequency r2 to approximately 100 to 200 Hz, the engine High damping characteristics can be effectively utilized when vibrations in the low frequency range such as shaking and bounce are input, and low dynamic spring characteristics can be effectively demonstrated when inputting vibrations in the medium to high frequency range that cause muffled noise when the vehicle is running. That's what happens.

Although one embodiment of the present invention has been described in detail above, this is a literal illustration, and the present invention is not to be construed as being limited only to this specific example.

For example, when setting the first resonance frequency: fl to a lower frequency side, it is effective to increase the arrangement interval 2T between the partition plates 38, 38, but such an arrangement interval should not be made too large. As a result, the liquid column resonance effect decreases. This is the communication hole 50 on both sides in the intermediate chamber 48.
It is presumed that this is because the fluid flow between the adjacent partition plates 38 and 38 becomes turbulent. The interval is small, specifically, the plate thickness of the partition plate 38: 6 to 7 of t.
It is desirable to make it less than double.

In addition, as another method 7 for setting the first resonance frequency: fl to a lower frequency side, the formation position of the communication hole 50.50 in the both side partition plates 38.38 is set to the partition plate 38.3.
It is also conceivable to shift the channel in a direction perpendicular to the opposing direction of the channels 8 to increase the actual length of the channel. Of course, those communication holes 5
If the deviation of 0.50 becomes too large, the liquid column resonance effect will decrease due to an increase in fluid flow resistance, etc. Therefore, in order to obtain a sufficient vibration damping effect, it is necessary to must overlap at least in part in the opposing direction of the partition plates 38 and 38.

Furthermore, in the embodiment, the plate thickness of the partition plates 38 and 38 and the inner diameter of the communication hole 50 are as follows:
Although they were set to the same value, it is also possible to set them to different values. However, in such a case, the second resonance frequency: f2 will occur at the side of the communication hole 50, 50 where the lower liquid column resonance point is set.

In addition, in the embodiment described above, an example was shown in which the present invention was applied to an automobile engine mount.
The present invention provides a cylindrical mount, a cylindrical bush, etc., which can define first and second fluid chambers in which relative internal pressure fluctuations are caused when vibration is input, with a partition plate separating them. It should be understood that the present invention may be advantageously applied to various types of mounts.

In addition, although not listed, the present invention can be implemented in embodiments with various changes, modifications, improvements, etc., based on the knowledge of those skilled in the art, and such embodiments are not limited to the present invention. It goes without saying that any of these are included within the scope of the present invention as long as they do not depart from the spirit of the invention.

(Effects of the Invention) As is clear from the above description, in the fluid-filled vibration damping mount according to the present invention, in one communicating flow path system, the liquid column resonance point and Since a point that can be considered can be generated, a good vibration isolation effect can be exhibited over a wide frequency range, and
In particular, compared to the conventional one with two communicating flow path systems,
The structure is simple and manufacturing costs can be advantageously reduced.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a specific example of an automobile engine mount to which the present invention is applied. FIG. 2 is a graph illustrating the anti-vibration characteristics of an engine mount having such a structure. Also, Figure 3 shows
FIG. 2 is an explanatory cross-sectional view showing an enlarged main part of the engine mount shown in FIG. 1; 10: First support fitting 12: Second support fitting 14: Rubber elastic body 34: Partition member 36: Elastic closure body
38: Partition plate 42: First fluid chamber 44: Second fluid chamber 48: Intermediate chamber 50: Communication hole Applicant Tokai Rubber Industries Co., Ltd. 33

Claims (1)

[Claims] A first support body and a second support body arranged at a predetermined distance from each other are elastically connected by a rubber elastic body interposed between them, and the first support body A fluid storage chamber in which a predetermined incompressible fluid is sealed is formed between the first support member and the second support, and a plurality of rigid partition plates are arranged facing each other at predetermined intervals in the fluid storage chamber. At least, first and second fluid chambers are formed on both sides of the plurality of partition plates, in which a relative fluid pressure difference is generated when vibration is input, and an intermediate portion of a predetermined volume is formed between the partition plates. defining a chamber, and further providing at least a portion of a communication hole in the opposing direction of the partition plate for each of the partition plates to allow the first and second fluid chambers to communicate with each other via the intermediate chamber. A fluid-filled anti-vibration mount characterized in that the mounts are formed in such a manner that they overlap each other.