JPH0570008B2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a fluid-filled vibration-isolating bushing, and more specifically, it has a good vibration-isolating function against both low-frequency vibrations and high-frequency vibrations input in the radial direction. This invention relates to a vibration-proof enclosed type vibration-proof bushing that can be obtained.

(Prior art) A type of anti-vibration bushing that is interposed between a predetermined mounting shaft and a cylindrical member constituting a vibration transmission system and connects them in an anti-vibration manner. Some devices are designed to attenuate or block the Examples include suspension bushings in automobiles and engine mounts in FF (front engine/front drive) cars.

By the way, in recent years, in such vibration-proof bushings, it has become possible to effectively reduce the vibration transmission rate for input vibrations in the target frequency range. an outer cylindrical member disposed eccentrically or eccentrically, and c interposed between the inner cylindrical member and the outer cylindrical member, opening to the outer circumferential surface at positions facing each other with the inner cylindrical member interposed therebetween. a cylindrical rubber elastic body having a pair of pocket portions, and d a predetermined incompressible fluid sealed in the pocket portion of the rubber elastic body, which is formed by fluid-tightly closing the pocket portion of the rubber elastic body with the outer cylinder member. and an orifice means for making the pair of fluid chambers communicate with each other, the flow action of the incompressible fluid flowing through the orifice means or the inertial mass of the fluid within the orifice means. Based on this effect, a so-called fluid-filled type is increasingly being adopted, which reduces the transmission rate of vibrations input in opposite directions of the pair of fluid chambers.

According to such a fluid-filled anti-vibration bushing,
It is possible to satisfactorily reduce the vibration transmission rate in a frequency range corresponding to the ratio of the cross-sectional area and length of the orifice means. By setting (tuning), it is possible to satisfactorily dampen vibrations in the target frequency range.

(Problem) However, with such a fluid-filled vibration-isolating bushing, as mentioned above, although a good vibration-isolating effect can be obtained for vibrations in the frequency range corresponding to the tuning frequency of the orifice means, for vibrations at other frequencies. It is difficult to say that a good vibration-proofing effect can be obtained with respect to vibrations in the region, and improvements have been desired.

The vibration-proofing bushings for the suspension bushings and engine mounts are suitable for high frequency vibration. It is desirable to have a good blocking effect against small-amplitude vibration input, and a good damping effect against low-frequency, large-amplitude input vibration. In anti-vibration bushings, although a good damping effect can be obtained for vibrations in the low frequency range by changing the cross-sectional area and length of the orifice means, it is not necessarily possible to obtain a sufficient damping effect for vibrations in the high frequency range. Conversely, if the cross-sectional area and length of the orifice means are set to correspond to vibrations in the high frequency range, a relatively good blocking effect can be obtained for vibrations in the high frequency range, but it is not necessarily effective for vibrations in the low frequency range. A sufficient damping effect cannot be obtained.

(Solution Means) Here, the present invention has been made against the background of the above-mentioned circumstances, and its gist is that as described above, a inner cylinder member, b an outer cylinder member, and c rubber In a fluid-filled vibration-proof bushing comprising an elastic body, a pair of fluid chambers, and an orifice means, at least one of the pair of fluid chambers is provided with:
A protrusion of a predetermined height protrudes from the inner cylindrical member toward the outer cylindrical member, and is located at the tip of the protrusion so that both ends in the direction of the bush axis are respectively attached to the inner wall of the fluid chamber. A partition plate of a predetermined thickness is provided so as to contact and fluid-tightly close the space between the partition plate and the inner wall, and so that both circumferential ends of the bush face the inner wall of the fluid chamber with a predetermined gap between them. That's true.

Here, generally, a rubber layer of a predetermined thickness is integrally provided at both ends of the partition plate in the direction of the bush axis, and the rubber layer has a predetermined compression distance with respect to the inner wall of the fluid chamber. By being pressed with such force, the space between both ends of the partition plate in the direction of the bush axis and the inner wall of the fluid chamber is fluid-tightly closed.

(Function/Effect) In such a fluid-filled vibration-proof bushing, when the rubber elastic body is elastically deformed based on the vibration load input in the opposite direction of the pair of fluid chambers, the vibration is caused through the orifice means that communicates the two fluid chambers. Of course, the incompressible fluid in these fluid chambers is made to flow with each other, and in at least one fluid chamber, both circumferential ends of the partition plate provided inside the fluid chamber and the opposing fluid chamber wall Incompressible fluid is forced to flow in the radial direction of the bush through the gap therebetween.

In other words, in the fluid-filled vibration-isolating bushing according to the present invention, vibrations input in opposite directions of a pair of fluid chambers are not only affected by the orifice means that communicates the two fluid chambers, but also by the partition plate disposed in the fluid chambers. The gap between the circumferential ends and the opposing inner wall of the fluid chamber also functions as an orifice, and therefore the cross-sectional area of the orifice means and the vibration input in the opposite direction of the fluid chamber are It is possible to satisfactorily reduce the transmissibility of vibration in a frequency range corresponding to the ratio to the length, and the cross-sectional area of the gap between both ends of the partition plate in the circumferential direction and the inner wall of the fluid chamber opposing thereto. It is possible to satisfactorily reduce the transmission rate of vibration in a frequency range corresponding to the ratio to the length.

Therefore, by setting (tuning) the cross-sectional area and length of the orifice means and the gap between the partition plate and the wall of the fluid chamber to correspond to vibrations in different frequency ranges, It is possible to obtain a good vibration isolation effect with respect to the input vibrations in the range, and by tuning one of them (generally the orifice means) to correspond to the vibration in the low frequency range and the other to correspond to the vibration in the high frequency range. As a result, it exhibits a good damping effect against input vibrations in the low frequency range, and
This makes it possible to obtain a fluid-filled anti-vibration bushing that exhibits a good isolation effect against input vibrations in a high frequency range.

(Example) In order to clarify the configuration of the present invention more specifically, a typical example will be shown in the drawings in the case where the present invention is applied to a cylindrical engine mount for a FF horizontal engine vehicle. This will be explained in detail based on the following.

First, FIGS. 1 and 2 show an example of a cylindrical engine mount according to the present invention. In these figures, numeral 10 denotes an inner cylindrical metal fitting as an inner cylindrical member, which has a thick-walled cylindrical shape. has been achieved.
A stopper metal fitting 12 of a predetermined thickness is fitted onto the outer peripheral surface of the inner cylindrical metal fitting 10 at the center in the axial direction, and a corresponding portion of the stopper metal fitting 12 is fitted into a predetermined recess. A rubber sleeve 16 as a rubber elastic body is integrally vulcanized and molded in a state where it is exposed inside the chamber, and an outer cylindrical metal fitting 18 as an outer cylindrical member is fitted onto the outer peripheral surface of this rubber sleeve 16. ing. The engine mount of this embodiment is attached to the vehicle body or a member on the engine side at the outer peripheral surface of the outer cylinder fitting 18, and is attached to the engine or a member on the car body side at the inner cylinder fitting 10. The engine is supported against vibrations against the vehicle body. Note that the rubber sleeve 16 has a substantially constant wall thickness, and the inner cylindrical metal fitting 10 and the outer cylindrical metal fitting 18 are thereby arranged concentrically.

Here, as shown in FIGS. 3 and 4, the rubber sleeve 16 has a pair of pocket portions 20 and 20 that are open on the outer circumferential surface and are opposed to each other with the inner cylindrical fitting 10 interposed therebetween. is formed. And here, each pocket part 2
0 and 20 are formed in an arcuate shape extending approximately half a circumference in the circumferential direction, with a width larger by a predetermined dimension than the thickness of the stopper metal fitting 12, and a depth that reaches the inner cylindrical metal fitting 10 at the bottom. There is.

Further, as shown in FIGS. 3 and 4, on the outer peripheral surface of the rubber sleeve 16, a metal outer sleeve 24 is provided with windows 22, 22 corresponding to the pockets 20, 20. They are integrally fixed by vulcanization adhesive. As shown in FIGS. 1 and 2, the outer cylindrical fitting 1
8 is fluid-tightly fitted to this outer sleeve 24, thereby allowing each pocket portion 20, 2
A pair of fluid chambers 26, 26 with 0 as a fluid storage space
is formed. Moreover, here, by performing the fitting operation of the outer cylindrical fitting 18 in a predetermined incompressible fluid,
A predetermined incompressible fluid such as water, alkylene glycol, polyalkylene glycol, silicone oil, or low molecular weight polymer is enclosed.

A sealing rubber layer 28 of a predetermined thickness is bonded to the inner peripheral surface of the outer sleeve 18 by integral vulcanization molding, and this sealing rubber layer 28 is bonded between the outer sleeve 24 and the outer sleeve 18. By being compressed, the fluid tightness of each fluid chamber 26, 26 is ensured. Further, after the outer cylinder metal fitting 18 has been subjected to an eight-way drawing process, both ends thereof are subjected to a roll caulking process and are fitted into the outer sleeve 24. Furthermore, the outer sleeve 24 is subjected to an eight-way drawing process before the outer cylinder fitting 18 is fitted thereto, thereby applying a predetermined precompression to the rubber sleeve 16.

On the other hand, the stopper fitting 12 is for regulating the relative displacement of the inner cylindrical fitting 10 and the outer cylindrical fitting 18 in the direction in which the fluid chambers 26, 26 face each other by a certain amount or more. As shown in FIG. 2, substantially trapezoidal stopper portions 30 and 32 are formed to protrude from a pair of opposite sides of a rectangular portion, and the center portion of the rectangular portion It has a central hole 34 located at. Each stopper part 30, 32 is connected to the fluid chamber 2.
The side portions of the rectangular portions from which the stopper portions 30 and 32 are projected are connected to the fluid chambers 26 and 2 with a phase relationship projecting approximately at the center of the fluid chambers 26 and 26.
As described above, each of the stopper parts 30, 3
2 comes into contact with the inner surface of the outer cylinder fitting 18,
Relative displacement of the inner cylindrical fitting 10 and the outer cylindrical fitting 18 in the opposing direction of the fluid chambers 26, 26 beyond a certain level is prevented.

In this embodiment, a pair of communication holes 36, 36 are formed at positions sandwiching the stopper parts 30, 32 of the stopper fitting 12, and communicate the fluid chambers 26, 26, respectively. The incompressible fluid contained in the fluid chambers 26, 26 can mutually flow through the communication holes 36, 36. In this embodiment, those communication holes 3
6 and 36 constitute an orifice means, and the transmission rate of vibration input in the opposite direction of the fluid chambers 26 and 26 is determined by the communication holes 36 and 36.
It is designed to be reduced based on the flow effect of the flowing incompressible fluid or the inertial mass effect.

In addition, here, the ratio of the total cross-sectional area (sum of cross-sectional areas): a ₁ and the length l ₁ of the communicating holes 36, 36: a ₁ /l ₁ corresponds to the frequency in the low frequency range: f ₁ . Based on the flow action or inertial mass effect of the incompressible fluid flowing through the communication holes 36, 36, shake, bounce, idle vibration, etc. corresponding to the tuning frequency _f1 are set. The transmissibility of vibrations in the low frequency range is reduced.

Further, as shown in FIGS. 1 and 2, each stopper part 30, 32 of the stopper fitting 12
Rectangular plate-shaped stopper plates 38 and 40 having a substantially arcuate cross section are disposed on the distal end surfaces of the stopper portions 30 and 32, respectively, and protrude by a predetermined dimension from each side surface of the stopper portions 30 and 32 in the mount axis direction and circumferential direction. It is set up. In this embodiment, the stopper plates 38 and 40 include metal plates 42 and 44, respectively, and buffer rubber layers 46 and 48 of approximately the same thickness that are integrally vulcanized on the outer peripheral surfaces of the metal plates 42 and 44, respectively. It is composed of a pair of thin side rubber layers 50, 50 integrally extending outward in the mount axis direction from both ends of the buffer rubber layers 46, 48 in the mount axis direction, and as described above. When the stopper portions 30 and 32 are disposed on the distal end surfaces thereof, both ends of the mount in the circumferential direction are connected to the fluid chambers 26 and 26.
are arranged to face the inner wall (inner surface of the outer cylindrical fitting 18) with a predetermined gap therebetween, and
Both ends in the axial direction of the mount are pressed against the inner walls of the fluid chambers 26, 26 in the axial direction of the mount (inner surfaces of the pocket parts 20, 20 of the rubber sleeve 16) at the side rubber layers 50, 50, respectively. It's summery.

In this embodiment, each fluid chamber 26, 26 is divided into approximately two parts in the radial direction of the mount by each stopper plate 38, 40. The radially inner and outer divided chambers are communicated only through gaps formed at both ends of the mount circumferential direction of each stopper plate 38, 40. As a result, when a vibration load is input in the opposite direction of the fluid chambers 26, 26,
The incompressible fluid contained in each of the fluid chambers 26, 26 is made to flow through the gap between them, based on the flow action or inertial mass effect of the incompressible fluid flowing through the gap. Also, the transmission rate of vibrations input to the opposite directions of the fluid chambers 26, 26 is reduced. As is clear from this, in this embodiment, each of the stopper plates 38 and 40 constitutes a partition plate, and each of the stopper parts 30 and 32 constitutes a protrusion. .

Here, the ratio of the cross-sectional area: a ₂ and the length: l ₂ of the gap in one (upper side in FIG. 1) fluid chamber 26: a ₂ /l ₂ is in a relatively high frequency region. frequency: f ₂ , and the cross-sectional area of the gap in the other fluid chamber 26 (lower side in FIG. 1): a ₂ ′ and length:
The ratio of a ₂ ′/l ₂ ′ to l ₂ ′ is set corresponding to the frequency f ₂ ′ that is higher than the above frequency f ₂ (see Fig. 1), which makes them Based on the flow action of the incompressible fluid flowing through the gap or the inertial mass effect, the transmission rate of vibrations in high frequency ranges such as muffled sound and engine transmitted sound corresponding to f ₂ and f ₂ ' is reduced. It's starting to feel like I'm being forced to do it.

Further, here, the stopper plate 3
8 and 40 are fixed to the respective stopper parts 30 and 32 by screw members 52, respectively, and the stopper parts 30 and 32 are fixed to the stopper plates 3 and 32 respectively.
It is adapted to be brought into contact with the inner surface of the outer cylindrical metal fitting 18 via 8 and 40.

Therefore, according to such an engine mount, like a conventional fluid-filled engine mount,
Based on the flow action or inertial mass effect of the incompressible fluid flowing through the orifice means (communicating passages 36, 36), the shake corresponding to the frequency f ₁ input into the opposite directions of the fluid chambers 26, 26 or Not only can input vibrations in the low frequency range such as bounce and idle vibrations be well damped, but also the mounting circumferential ends of each stopper plate 38, 40 and the fluid chamber 2
Based on the flow action or inertial mass effect of the incompressible fluid flowing in the gap between the inner walls of the parts 6 and 26,
Frequencies: It can effectively block muffled noise and engine transmitted sound in relatively high frequency ranges corresponding to f ₂ and f ₂ ′, and therefore it is better able to block input vibrations in a wider frequency range than conventional engine mounts. This makes it possible to obtain good vibration damping effects.

Furthermore, according to the engine mount of this embodiment,
As described above, both ends of each stopper plate 38, 40 in the mount axis direction are pressed against the inner walls of each fluid chamber 26, 26 at the side rubber layer 50, thereby preventing fluid between them. The incompressible fluid is held tightly between the stopper plates 3
Since the flow is allowed to flow in the radial direction of the mount only through the gaps formed at both circumferential ends of the mounts 8 and 40, the flow effect or inertial mass effect of the incompressible fluid flowing through those gaps is reduced. Tuning frequency of anti-vibration effect based on:
It has the advantage of good selectivity for f ₂ and f ₂ ', and therefore, the vibration isolation function against vibrations in the tuning frequency range of these gaps is effective at both ends of the stopper plates 38 and 40 in the axial direction of the mount. Compared to the case where a gap is formed between the part and the inner wall of the fluid chambers 26, 26 to allow the flow of the incompressible fluid,
It has some advantages that are said to be superior.

In this embodiment, as described above, the tuning frequency of the gap between the both ends of each stopper plate 38, 40 in the mount axis direction and the inner wall of the fluid chambers 26, 26 is: f ₂ , f ₂ ' were supposed to be different from each other, but their tuning frequencies:
It is also possible to match f ₂ and f ₂ ', and it is also possible to omit one of the stopper plates 38, 40.

In addition, the engine mount of this example is usually
Although the fluid chambers 26 and 26 are arranged in such a manner that their opposing directions coincide with the vibration input direction, the fluid chamber 2
It is also possible to arrange the vibration input direction in such a manner that the opposing directions of the vibration input devices 6 and 26 are rotated by about 5 to 80 degrees about their respective axes. In this way, the incompressible fluid sealed in each fluid chamber 26, 26 can also flow in the circumferential direction of the mount through the narrowed part narrowed by each stopper part 30, 32. The vibration transmissibility of input vibrations in a frequency range corresponding to the shape (cross-sectional area, length) of each constriction portion narrowed by the stopper portions 30, 32 is also reduced.

Next, another embodiment of the present invention will be described based on FIG. Note that, in the following, only the parts that are different from the engine mount of the previous embodiment will be explained in detail, and the detailed explanation of other parts will be omitted.

That is, as shown in FIG. 5, in the engine mount of this embodiment, unlike the previous embodiment, only one stopper plate 38 is provided, and the stopper plate 38 is A through hole 60 with a predetermined cross-sectional area: a ₃ is formed so as to pass through in the thickness direction. And this through hole 6
A thin rubber elastic body 62 is located in the middle of the stopper plate 38 and is movable over a small distance in the thickness direction of the stopper plate 38 while fluid-tightly blocking the through hole 60.
is arranged so that the rubber elastic body 62 is moved in the thickness direction of the stopper plate 38 in accordance with the fluid pressure difference between the incompressible fluid inside and outside the stopper plate 38.

Note that, as shown in detail in FIG. 6, this rubber elastic body 62 is disposed with its outer peripheral edge portion accommodated in an annular groove 64 formed on the inner surface of the through hole 60. There is.

In addition, here, the cross-sectional area of the through hole 60: a ₃ and the length: l ₃ (see Figure 6) mean that the ratio: a ₃ /l ₃ is the frequency of a relatively high frequency range: f ₃ (however, , f ₃ > f ₂ ), thereby reducing the transmission rate of vibrations in the high frequency range such as muffled sound and engine transmitted sound corresponding to the tuning frequency f ₃ . It's becoming like that.

Therefore, when vibration is input in the opposite direction of the fluid chambers 26, 26, the through hole 60 is opened based on the reciprocating movement of the rubber elastic body 62 in the thickness direction of the stopper plate 38.
The incompressible fluid is allowed to flow relatively therein, and the cross-sectional area: a ₃ and length: l ₃ of the through hole 60 are determined based on the flow action or inertial mass effect of the incompressible fluid. The transmission rate of vibration in the frequency range corresponding to the ratio: a ₃ /l ₃ (tuning frequency: f ₃ ) is advantageously reduced. Note that the movement stroke of the rubber elastic body 62 is set corresponding to the amplitude of the vibration of the tuning frequency: _f3 , and for the amplitude of the vibration of the frequency: _f2 ,
The moving distance is made sufficiently small.

According to the engine mount with this structure,
Communication holes 36, 36 and stopper plate 38
Since the incompressible fluid is caused to flow through the gap between both ends of the mount in the circumferential direction and the inner wall of the fluid chamber 26, the input vibration in the low frequency range corresponding to the frequency _f1 is It is possible to obtain a good damping effect for the input vibration, or to reduce the transmitted force according to f ₁ , and also to have good frequency selectivity for the input vibration in the high frequency range corresponding to the frequency f ₂ . Not only can a good blocking effect be obtained, but also a good blocking effect can be obtained for input vibrations in a high frequency range corresponding to the tuning frequency of the through hole 60: _f3 . Similar to the embodiment described above, it is possible to exhibit a good vibration isolation function against input vibrations in a wider frequency range than conventional engine mounts.

In this embodiment, the rubber elastic body 62 is held movable a predetermined distance in the thickness direction of the stopper plate 38 by having its outer peripheral edge accommodated in the annular groove 34. This allows the stopper plate 38 to be displaced by a predetermined amount in the thickness direction. The body 62 is moved to the stopper plate 38.
It is also possible to displace a predetermined amount in the plate thickness direction based on its elastic deformation.

Although several embodiments of the present invention have been described in detail above, these are merely examples, and it goes without saying that the present invention should not be interpreted as being limited to these specific examples.

For example, in the embodiment, the stopper plate 3
The side rubber layers 50, 50 protruding on both sides in the mount axis direction of the mounts 8, 40 are connected to the buffer rubber layers 46, 4.
Although the side rubber layers 50, 50 are formed integrally with the buffer rubber layers 46, 48, it is also possible to configure them separately from the buffer rubber layers 46, 48.

Further, in the embodiment described above, the stopper parts 30 and 32 are employed as protruding parts to restrict the relative displacement of the inner cylindrical fitting 10 and the outer cylindrical fitting 18 in the direction in which the fluid chambers 26 and 26 face each other by a predetermined amount or more. However,
The protrusion does not necessarily have to function as a stopper.

Furthermore, in the embodiment described above, the inner tube fitting 10 and the outer tube fitting 18 were arranged concentrically, but the inner tube fitting 10 and the outer tube fitting 18 may be arranged eccentrically as necessary. It is also possible.

Furthermore, in the above embodiment, an example was described in which the present invention was applied to an engine mount of a front-wheel drive vehicle, but the present invention can also be applied to a suspension bushing of an automobile.

In addition, although not listed one by one, various modifications,
Things that can be implemented with modifications, improvements, etc. are:
It goes without saying.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view (-cross-sectional view in FIG. 2) showing an example of an engine mount according to the present invention, and FIG. 2 is a cross-sectional view (--cross-sectional view in FIG. 1). FIG. 3 is a cross-sectional view (-cross-sectional view in FIG. 4) corresponding to FIG. 1 showing an integrally vulcanized product of the rubber sleeve shown in FIG.
The figure is a - sectional view in FIG. 3. Fifth
The figure is a sectional view corresponding to FIG. 1 showing another embodiment of the present invention, and the sixth figure is an enlarged view of the main part thereof. 10: Inner cylinder metal fitting (inner cylinder member), 12: Stopper metal fitting, 16: Rubber sleeve (cylindrical rubber elastic body),
18: Outer cylinder metal fitting (outer cylinder member), 26: Fluid chamber, 3
0, 32: Stopper part (protruding part), 36: Communication hole (orifice means), 38, 40: Stopper plate (partition plate), 42, 44: Metal plate,
46, 48: Buffer rubber layer, 50: Side rubber layer, 6
0: Through hole, 62: Rubber elastic body (thin plate shape).

Claims (1)

[Scope of Claims] 1: an inner cylinder member; an outer cylinder member disposed concentrically or eccentrically on the outside of the inner cylinder member; an interposed member between the inner cylinder member and the outer cylinder member; , a cylindrical rubber elastic body having a pair of pocket portions that are located on opposite sides of the inner cylinder member and open to the outer circumferential surface; A fluid-filled anti-vibration bushing comprising: a pair of fluid chambers that are tightly closed and filled with a predetermined incompressible fluid; and orifice means for making the pair of fluid chambers communicate with each other. At least one of the pair of fluid chambers is provided with a protrusion of a predetermined height that protrudes from the inner cylindrical member toward the outer cylindrical member. Both end portions in the circumferential direction of the bush are opposed to the inner wall of the fluid chamber with a predetermined gap between them, so that both end portions in the circumferential direction of the bush are in contact with the inner wall of the fluid chamber to fluid-tightly close the space between the bushing and the inner wall. A fluid-filled vibration-proof bushing characterized in that a partition plate having a predetermined thickness is provided so as to do so. 2. The partition plate is integrally provided with a rubber layer of a predetermined thickness at both ends in the axial direction of the bush, and the rubber layer is pressed against the inner wall of the fluid chamber with a predetermined compression margin. 2. The vibration-proof bushing according to claim 1, wherein a space between both ends of the partition plate in the direction of the bush axis and an inner wall of the fluid chamber is fluid-tightly closed. 3. A thin plate-like structure having a through hole of a predetermined cross-sectional area penetrating through the partition plate in its thickness direction, and capable of being displaced in a predetermined direction in the thickness direction of the partition plate while blocking the through hole. The vibration-proof bushing according to claim 1 or 2, wherein a thin film-like rubber elastic body is disposed.