JPS63289349A - Fluid sealing type vibrationproof bush - Google Patents

Abstract

PURPOSE:To bring an excellent vibro-isolating function into full play by constituting vibrations of low frequency and large amplitude so as to be damped by action of a fluid flowing an orifice and vibrations of high frequency and small amplitude so to be intercepted by action of another fluid flowing a bottleneck part, respectively. CONSTITUTION:Each setting frequency of orifices 50 and 52 is set to be low, and vibrations of low frequency and large amplitude to be inputted in the opposed direction of a pressure receiving chamber 44 and an axial through void 34 are favorably damped by inertial mass effect or liquid column resonance action of an incompressible fluid flowing in these orifices. On the other hand, when the vibrations are of high frequency and small amplitude, length and a sectional area of a bottleneck part 67 between the side extending part 66 installed in a tip part of a stopper 58 and a wall of the pressure receiving chamber 44 is set as corresponding to the high frequency, whereby the input vibration is favorably interceptable by the inertial mass effect or the liquid column resonance action of the incompressible fluid flowing in the bottleneck part 67. Consequently, such a vibro-isolating function that is more excellent than ever before can be demonstrated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a fluid-filled vibration damping bushing, and more specifically, to a fluid-filled vibration damping bushing that provides good protection against both low frequency vibrations and high frequency vibrations input in the radial direction. This invention relates to a fluid-filled anti-vibration bundle that can exhibit a vibration function.

(Conventional wave f4・te) A type of vibration-proof bushing that is interposed between a predetermined mounting shaft and a cylindrical holding part that constitute a vibration transmission system, and connects them in a vibration-proof manner. Some devices are designed to attenuate or block vibrations input in this direction. Examples include suspension bushings for automobiles and cylindrical engine mounts for FF (front engine/front drive) cars.

By the way, such anti-vibration racks are required to have good isolation performance against high-frequency, small-amplitude input vibrations, while good damping performance is required against low-frequency, large-amplitude input vibrations. However, in conventional anti-vibration bushings, the anti-vibration function against human vibration was exclusively based on the elastic deformation of the rubber elastic body. It is difficult to satisfy this requirement, and there is a problem in that it is difficult to achieve a sufficient damping effect, especially for input vibrations of low frequency and large amplitude.

Therefore, in recent years, in Japanese Patent Publication No. 48-36151 and Japanese Patent Publication No. 52-16554, a pair of fluid chambers are formed in a cylindrical rubber elastic body so as to face each other in the vibration input direction, and the fluid chambers are A fluid-filled vibration-proof bunsch has been proposed in which the two fluid chambers are communicated through an orifice, and a predetermined incompressible fluid contained in each fluid chamber can mutually flow through the orifice during radial vibration. ing.

According to such a fluid-filled vibration-proof bushing, input vibration in a frequency range set (tuned) for the orifice is suppressed based on the inertial mass effect or liquid column resonance effect of the incompressible fluid flowing through the orifice. Therefore, by setting the tuning frequency of the orifice to a low frequency, it is possible to exhibit a good damping effect against low-frequency, large-amplitude input vibrations.

(Problem) However, as mentioned above, such a fluid-filled vibration damping bund cannot provide a good damping effect for input vibrations in the frequency range (tuning frequency range) set for the orifice. However, it is difficult to obtain a good vibration isolation function against input vibrations in other frequency ranges, especially for input vibrations in a frequency range higher than the tuning frequency range of the orifice. On the other hand, there was a problem in that the incompressible fluid became difficult to flow through the orifice, and the vibration damping function was rather deteriorated.

On the other hand, as a modified type of the fluid-filled vibration-isolating bushing as described above, one side of the fluid chamber is not used as a pressure-receiving chamber into which vibrations to be damped are input, but one side is used as a pressure-receiving chamber into which vibrations to be damped are input, and the other side is used as a pressure-receiving chamber that can be easily bulged and deformed. An equilibrium chamber is defined by a flexible thin film, and the volume change of the equilibrium chamber due to the deformation of the flexible thin film allows the volume of the pressure receiving chamber to change, whereby the incompressible fluid passes through the orifice and fills the pressure receiving chambers. A system that allows mutual flow between the liquid and the equilibrium chamber has been considered. However, even in this type of fluid-filled anti-vibration bushing, there are problems similar to those of the type disclosed in the above-mentioned publications, such as low frequency - large amplitude input vibration and high frequency - small amplitude input vibration. It has been difficult to simultaneously exhibit good vibration-proofing function.

In addition, for those fluid-filled anti-vibration bushings,
A fluid pressure absorption mechanism equipped with a movable plate, such as that used in the fluid-filled vibration isolation support disclosed in Japanese Patent Application Laid-open No. 3-5316 and Japanese Patent Application Laid-Open No. 57-9340, is provided, and this fluid pressure absorption mechanism Is it possible to reduce the dynamic spring constant by absorbing fluid pressure, thereby achieving a good isolation effect even against high-frequency, small-amplitude human vibrations? If adopted, the bushing structure would be extremely complicated, which would be economically disadvantageous, and there would be space constraints, so it would be difficult to adopt it easily.

(Solution Means) The present invention was made against the background of the above-mentioned circumstances, and is characterized by a fluid-filled type that blocks or damps vibrations input in the radial direction, as described above. The anti-vibration bushing includes (a) an inner cylinder member, (b) an outer cylinder member having a plurality of windows arranged concentrically or eccentrically on the outside of the inner cylinder member, and (C) the outer cylinder. a seal sleeve that is fitted onto the outer peripheral surface of the member and fluid-tightly closes the plurality of windows; (d) interposed between the outer cylindrical member and the inner cylindrical member to connect them; A pocket portion located on one side of the opposing portions with the inner cylinder member interposed therebetween and having one of the windows of the outer cylinder member as an opening, and a cavity located on the other side that penetrates in the axial direction. (e) the pocket portion of the rubber elastic body is fluid-tightly closed by the sealing sleeve at the opening thereof, and the vibration that should be vibration-isolated is input to the pocket portion of the rubber elastic body; (f) a pressure-receiving chamber that is easily bulged and deformed, and (f) is formed in a through space in the axial direction of the rubber elastic body, with the remainder of the window of the outer cylinder member serving as an opening. A recess surrounded by a thin wall made of rubber elastic material is
an equilibrium chamber formed by fluid-tightly closing the opening window with the sealing sleeve;
(g) a predetermined incompressible fluid sealed in the equilibrium chamber and the pressure receiving chamber; (h) the equilibrium chamber and the pressure receiving chamber communicate with each other, and the incompressible fluid communicates with the equilibrium chamber and the pressure receiving chamber; an orifice that allows reciprocal flow to and from the chamber;
i) a stopper part of a predetermined height provided in the pressure receiving chamber and extending radially outward from the bottom of the pocket part; (j) a stopper part extending laterally from a distal end portion of the stopper part; and a lateral extending portion which is provided in a projecting state and forms a predetermined narrowed portion around the inner wall of the pressure receiving chamber.

(Operation/Effect) According to the fluid-filled anti-vibration bushing according to the present invention,
As with conventional fluid-filled vibration-isolating bushings, by setting the tuning frequency of the orifice to a low frequency, the pressure receiving chamber is This means that it is possible to satisfactorily attenuate low-frequency, large-amplitude vibrations that are input in the direction opposite to the through space in the axial direction.

On the other hand, if the tuning frequency of the orifice is set to a low frequency, when the vibration input in the opposite direction between the pressure receiving chamber and the through space in the axial direction is of high frequency and small amplitude, the incompressible fluid is It becomes difficult to flow through the orifice and therefore the reduction in dynamic spring constant achieved by flowing an incompressible fluid through the orifice is less likely to be expected.

However, in this case, the incompressible fluid is allowed to flow in the radial direction of the bushing through the narrowed part formed between the lateral extending part provided at the tip side of the stomper part and the wall of the pressure receiving chamber. By setting (tuning) the length and cross-sectional area of the constriction to correspond to high frequencies, the inertial mass effect or liquid column resonance effect of the incompressible fluid flowing through the constriction can be reduced. On the basis of the,
This makes it possible to effectively block the high-frequency, small-amplitude input vibration.

In other words, according to the fluid-filled vibration-isolating bushing according to the present invention, low-frequency and large-amplitude vibrations input in the bushing radial direction can be suppressed by the inertial mass effect of the incompressible fluid flowing through the orifice or liquid column resonance. Based on the action, it can exhibit a good damping effect like the conventional fluid-filled vibration-isolating bushing, but it also has a good damping effect against high-frequency and small-amplitude input vibrations.
Better performance than conventional fluid-filled vibration damping bushings based on the inertial mass effect or liquid column resonance effect of the incompressible fluid flowing through the constriction formed between the lateral extension and the wall of the pressure receiving chamber. Therefore, it becomes possible to exhibit a vibration isolation function superior to the conventional one against input vibration in the radial direction of the bushing.

Moreover, according to the present invention, such a vibration isolation function can be obtained simply by providing a lateral extension at the tip end of the stopper provided in the pressure receiving chamber. Compared to the case where a mechanism is provided, the structure is simpler and economically advantageous.

In addition, in the fluid-filled vibration-isolating bushing according to the present invention, a stomper part is provided in the pressure receiving chamber, and when the inner cylindrical member and the outer cylindrical member (seal sleeve) undergo a certain relative displacement, the tip of the stomper part Because the bushings are brought into contact with the inner circumferential surface of the seal sleeve, excessive displacement between the inner and outer cylinder members may occur, and the predetermined shaft and There is an advantage that excessive displacement with the cylindrical holding part can be effectively prevented based on the contact.

(Example) Hereinafter, in order to clarify the present invention more specifically,
The present invention is FF (front engine/front drive)
An example of application to a cylindrical engine mount used for anti-vibration support of a vehicle power unit will be described in detail with reference to the drawings.

First, in FIGS. 1 to 3, 10 and 12 are
Each of them includes a cylindrical inner metal fitting as an inner cylinder member and a cylindrical outer metal fitting as an outer cylinder member, which are arranged eccentrically by a predetermined amount in the radial direction of the mount, and are interposed between them. They are elastically connected by a rubber sleeve 14 as a rubber elastic body. In addition, the outer cylinder fitting 12
A metal sleeve 16 as a sealing sleeve is provided on the outer peripheral surface of the
is fitted. The engine mount of this embodiment is fitted onto the outer peripheral surface of the metal sleeve 16 into a cylindrical holding portion on the side of the power unit including the engine or the side of the vehicle body, and the inner cylindrical metal fitting 10
The power unit is inserted into the inner hole 18 of the vehicle body or the power unit to support the power unit against vibration.

Note that the inner cylindrical metal fitting 10 and the outer cylindrical metal fitting 12, as well as the inner cylindrical metal fitting 10 and the metal sleeve 16, are positioned substantially concentrically when the weight of the power unit is applied. Further, the rubber sleeve 14 is connected to the inner cylinder fitting 10.
and is integrally vulcanized and bonded to the outer cylindrical metal fitting 12.

Here, as shown in FIGS. 4 to 6, the outer cylindrical fitting 12 vulcanized and bonded to the outer circumferential surface of the rubber sleeve 14 has an inner cylindrical fitting 12 in an eccentric direction with respect to the inner cylindrical fitting 10. A pair of windows 20 and 22 are formed to face each other with the window 10 in between, and on the outer peripheral surface thereof,
A pair of circumferential orifice grooves 2 are located at opposing positions with the inner cylinder fitting 10 in between and connect the windows 20 and 22.
4°26 is formed. Further, on the outer peripheral surface of the outer cylinder fitting 12 excluding the openings of the orifice grooves 24 and 26, seal rubber layers 28 and 28 are provided at both ends in the axial direction.
A sealing rubber layer 30 having a predetermined thickness is integrally vulcanized and molded with the gong 1 and the sleeve 14.

As shown in FIGS. 4 to 7, the rubber sleeve 14 has a pocket 32 of a predetermined depth that opens into one of the windows 20 of the outer cylindrical fitting 12. On the other hand, a cavity 34 is formed at a portion corresponding to the other window portion 22 and extending through the window portion 22 in the axial direction. Also,
In such a space 34, a hole I/section 3 is inserted through the orifice grooves 24 and 26, with a part of the window 22 serving as an opening.
A pair of recesses 40.4.2 defined by thin wall portions 36 and 38, which are easily bulged and deformed, are formed, respectively, in communication with the recesses 40.4.2. As is clear from FIGS. 4 and 5, the openings of the recesses 40 and 42 are connected by a rubber layer having a predetermined thickness and forming a part of the rubber sleeve 14.

In this embodiment, as shown in FIGS. 1 to 3, the metal sleeve 16 is fitted onto the outer cylindrical fitting 12 fixed to the outer peripheral surface of the rubber sleeve 14. As a result, the openings of the window portions 20, 22, the pocket portion 32, and the recesses 40, 42 are respectively fluid-tightly closed, and the internal spaces of the hole I portion 32 and the recesses 40, 42 are closed with fluid. A pressure receiving chamber 44 and a pair of equilibrium chambers 46 and 48 are formed as accommodation spaces. In addition, by fluid-tightly closing the openings of the orifice grooves 24 and 26, the pressure receiving chamber 44 and each equilibrium chamber 4
Orifices 50, 52 communicating with 6, 48 are formed respectively. Furthermore, in this embodiment, the fitting operation of the metal sleeve 16 is performed in a predetermined incompressible fluid, so that the pressure receiving chamber 44 and each equilibrium chamber 46.
A predetermined incompressible fluid such as water, alkylene glycol, polyalkylene glycol, silicone oil, or a low molecular weight polymer is sealed within 48 .

Note that the metal sleeve 16 is hexagonally drawn and fixed to the outer cylindrical fitting 12. Furthermore, after the metal sleeve 16 is fitted, the engine mount of this embodiment is passed through a predetermined die to set its external dimensions to desired dimensions. Furthermore, the orifice 50.52 is formed with a cross-sectional area and a length corresponding to vibrations in a predetermined low frequency range.
Based on the inertial mass effect or liquid column resonance effect of the incompressible fluid flowing through or located in the orifices 50, 52, vibrations in the low frequency range can be well damped.

Further, as shown in FIGS. 4 to 6, the inner cylindrical fitting 10 vulcanized and bonded to the inner circumferential surface of the rubber sleeve 4 has a central portion located in the axial direction thereof. A stopper fitting 54 in the form of a longitudinal block with a predetermined thickness is inserted into the central hole 5.
It is press-fitted and fixed at 6. Each longitudinal end of the stopper fitting 54 projects into the pocket portion 32 and the cavity 34 at a predetermined height.

In this embodiment, both ends of the stopper metal fitting 54 in the longitudinal direction are used to prevent excessive relative displacement between the inner cylinder metal fitting 10 and the outer cylinder metal fitting 12, and furthermore, to restrict excessive relative displacement between the power unit and the vehicle body. This is the stopper portion 58,60.

Note that the rubber sleeve 14 is attached to the stopper metal fitting 5.
4 is vulcanized and molded to the inner cylindrical fitting 10 which is press-fitted and fixed. Further, the stopper portion 60 protruding toward the cavity 34 side of the stopper fitting 54 is connected to the rubber sleeve 1.
4 and is covered with a cushioning rubber layer having a predetermined thickness.

Here, as shown in FIGS. 4 and 5, a female threaded hole 62 is formed in the distal end surface of the stopper part 58 that protrudes into the pressure receiving chamber 44 of the stopper fitting 54. As shown in Figures 1 and 2,
The male screw 64 screwed into the female screw hole 62 causes the outer peripheral edge to extend laterally around the stopper part 58, in other words, the outer peripheral edge extends from the stopper part 58 in the mount axis direction. A rectangular plate-shaped lateral extending member 66 having a substantially arcuate cross section is fixed to the mount so as to protrude by a predetermined distance in the circumferential direction of the mount.

In this embodiment, the lateral extending member 66 divides the pressure receiving chamber 44 into approximately two halves in the bush radial direction corresponding to the eccentric direction of both metal fittings 10.12, that is, the vibration input direction. An annular narrowed portion 67 in a direction perpendicular to the vibration input direction is formed between the outer peripheral edge of the extending member 66 and the inner wall of the pressure receiving chamber 44, and the inner cylinder fitting IO and the outer cylinder are separated by the vibration input. When the fitting 12 is moved relative to the fitting 12 in their eccentric direction, the incompressible fluid within the pressure receiving chamber 44 is caused to flow in the radial direction of the bushing through the narrowed portion 67.

Note that the narrowed portion 67 is formed in the vibration direction (both metal fittings 10
．． The length l (see FIGS. 1 and 2) in the eccentric direction of the orifice 50.
The tuning frequency is set to correspond to a frequency higher than the tuning frequency of Based on the resonance effect, input vibrations in a high frequency range corresponding to the tuning frequency of the narrowed portion 67 can be effectively blocked.

Moreover, here, the side extending member 66 has a male thread 64.
a reinforcing metal fitting 68 fixed to the stopper part 58 by;
It consists of a buffer rubber layer 70 of a predetermined thickness integrally vulcanized on its outer peripheral surface, and the buffer rubber layer 70 has a male screw 6.
4 is formed into a through hole 72 for screwing into the female screw hole 62.

Furthermore, as is clear from the above description, in this embodiment, the outer peripheral edge portion of the lateral extension part +166 that protrudes laterally from the tip of the stomper part 58 constitutes a lateral extension part.

Therefore, according to the engine mount with this structure,
When low-frequency, large-amplitude vibration is input between the inner cylinder fitting 10 and the outer cylinder fitting 12 in the direction facing the pressure receiving chamber 44 and the cavity 34, the pressure receiving chamber 44, each equilibrium chamber, 16.48 An incompressible fluid is forced to flow through the orifices 50, 52 between the incompressible fluid and the inertia of the incompressible fluid flowing through or located in the orifices 50, 52, similar to conventional fluid-filled mounts. Based on the mass effect or liquid column resonance effect, the low frequency and large amplitude vibrations are well damped. Note that each equilibrium chamber 46 of the incompressible fluid.
48 through the thin walls 36.3 that define them.
8, and their equilibrium chambers 46
．． The incompressible fluid flows out from 48 into the pressure receiving chamber 44 by contraction and deformation of the thin wall portions 36 and 38.

Furthermore, if the vibration input in the opposite direction between the pressure receiving chamber 44 and the cavity 34 is of high frequency and small amplitude, it becomes difficult for the incompressible fluid to flow through the orifice 50, 52. Therefore, the reduction in dynamic spring constant achieved by flowing an incompressible fluid through the orifices 50, 52 is hardly expected. However, in this case, since the incompressible fluid in the pressure receiving chamber 44 is allowed to flow in the radial direction of the mount through the narrowed part 67, the side of the incompressible fluid located in the narrowed part 67 is Based on the inertial mass effect or liquid column resonance effect according to the relative flow action on the horizontally extending member 42,
The high frequency and small amplitude vibrations are effectively blocked. In other words, compared to a conventional engine mount in which such a narrowed portion 67 is not formed, the effect of blocking high-frequency, small-amplitude vibrations is greatly improved.

As described above, the cylindrical engine mount according to the present embodiment has a good damping effect, as in the conventional case, against low-frequency, large-amplitude vibrations that are manually applied in the opposite direction between the pressure receiving chamber 44 and the cavity 34. It is possible to exhibit a better isolation effect than conventional methods against small-amplitude vibrations, such as force and high frequency. It can provide better attenuation or isolation than a mount.

Moreover, according to the engine mount of this embodiment, such a vibration isolation function can be obtained with an extremely simple structure.
The manufacturing cost can also be kept low.

Further, according to this embodiment, since the stopper portions 58 and 60 are provided protruding into the pressure receiving chamber 44 and the cavity 34, respectively, excessive displacement between the inner cylindrical metal fitting 10 and the outer cylindrical metal fitting 12, Furthermore, there is also the advantage that excessive displacement between the power unit and the vehicle body can be effectively prevented.

Although one embodiment of the present invention has been described in detail above, this is merely an example, and it goes without saying that the present invention should not be interpreted as being limited to this specific example.

For example, in the above embodiment, the side extending member 66 constituting the side extending portion was configured separately from the stopper fitting 54, but the side extending member 66, that is, the side extending member 66, The reinforcing metal fitting 68 of the member 66 can also be configured integrally with the stomper metal fitting 54. Note that the stopper portion 60 that protrudes toward the space 34 does not necessarily need to be provided, and the thickness of the stopper fitting 54 (thickness in the mount axis direction) does not necessarily need to be constant.

In addition, in the embodiment described above, the recesses 40.42 constituting the equilibrium chambers 46,48 were formed with each of the windows 22 of the outer cylinder fitting 12 as openings; The recesses 40° 42 of 46.48 can also be formed with mutually independent windows formed in the outer cylindrical fitting 12 as openings. Moreover, the equilibrium chambers 46, 48 can also be formed as one equilibrium chamber, and it is also possible to employ only one of the equilibrium chambers 46, 48 as an equilibrium chamber.

Furthermore, in the embodiment, the inner cylinder fitting 10 and the outer cylinder fitting 12
Although these are arranged eccentrically by a predetermined amount in the radial direction of the mount, it is also possible to arrange them concentrically.

Furthermore, in the above embodiment, an example was described in which the present invention was applied to a cylindrical engine mount for a front-wheel drive vehicle.
It can also be applied to vibration-proof bushings and vibration-proof mounts other than cylindrical engine mounts for front-wheel drive vehicles, such as suspension bushes for automobiles.

Although not listed here, various other modifications may be made without departing from the spirit of the present invention.

It goes without saying that the present invention can be implemented with modifications, improvements, etc.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of a cylindrical engine mount for a front-wheel drive vehicle according to the present invention, and FIGS. be. FIG. 4 is a sectional view corresponding to FIG. 1 showing an integrally vulcanized product of the rubber sleeve in the engine mount of No. 1119, and FIGS. They are a sectional view, a vr-vr sectional view, and a sectional view taken along the line ■-■. 10: Inner cylinder metal fitting (inner cylinder member) 12: Outer cylinder metal fitting (outer cylinder member) 14: Rubber sleeve (rubber elastic body) 16: Metal sleeve (seal sleeve) 20.22: Window part 24.26F orifice groove 32: Pocket portion 34: Vacant space 36.38: Thin wall portion 40, 42: Recess 44: Pressure receiving chamber 46, 48: Equilibrium chamber 50.52 Niorifice 54: Stopper fitting 58. 60: Stopper portion 66: Laterally extending member 67: Narrowed portion 68: Reinforcement fitting 70: Buffer rubber layer Applicant: Tokai Rubber Industries, Ltd. Figure 1 Figure 4

Claims (1)

[Scope of Claims] An inner cylindrical member; an outer cylindrical member having a plurality of windows disposed concentrically or eccentrically on the outside of the inner cylindrical member; , a sealing sleeve that fluid-tightly closes the plurality of windows; and a sealing sleeve that is interposed between the outer cylinder member and the inner cylinder member to connect them, and that faces across the inner cylinder member. a rubber elastic body having a pocket located on one side and having one of the windows of the outer cylindrical member as an opening, and a cavity located on the other side passing through in the axial direction; a pressure-receiving chamber into which vibrations to be damped are input, which is formed by fluid-tightly closing the opening of the pocket portion of the body with the sealing sleeve; A recess surrounded by a thin wall made of a rubber elastic material that is easily expanded and deformed is formed in the through space with the remainder of the window of the outer cylinder member serving as an opening. an equilibrium chamber formed by fluid-tightly closing the opening window with the seal sleeve; a predetermined incompressible fluid sealed in the equilibrium chamber and the pressure receiving chamber; and the equilibrium chamber and the pressure receiving chamber. an orifice that communicates with the chamber and allows the incompressible fluid to mutually flow between the equilibrium chamber and the pressure receiving chamber; A stopper portion of a predetermined height, which is provided so as to extend from the top, and an inner wall of the pressure receiving chamber, which is provided so as to extend laterally from a distal end portion of the stopper portion, around a predetermined narrowed portion. and a lateral extension formed in the fluid-filled vibration damping bushing.