JPH0555739B2 - - Google Patents

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a fluid-filled vibration-isolating bushing, and more specifically, to a vibration-isolating bushing having good vibration-isolating function against both low-frequency vibrations and high-frequency vibrations input in the radial direction. This invention relates to a fluid-filled anti-vibration bushing that can exhibit the following characteristics.

(Prior art) 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 input vibrations. Examples include suspension bushings in automobiles and cylindrical engine mounts in front-engine, front-drive (FF) cars.

By the way, such anti-vibration bushings are required to have good isolation performance against high-frequency, small-amplitude input vibrations, but are also required to have good damping performance against low-frequency, large-amplitude input vibrations. However, in conventional anti-vibration bushings, the anti-vibration function against these input vibrations was exclusively based on the elastic deformation of the rubber elastic body. The problem was that it was difficult to satisfy the requirements, and in particular, it was not possible to exhibit a sufficient damping effect against 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 bushing has been proposed in which the two fluid chambers are connected through an orifice so that predetermined incompressible fluids contained in each fluid chamber can mutually flow through the orifice when vibration is input in the radial direction. ing.

According to such a fluid-filled anti-vibration bushing,
Based on the inertial mass effect or liquid column resonance effect of the incompressible fluid flowing through the orifice, input vibrations in the frequency range set (tuned) for the orifice can be well damped. 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 to be solved) However, in the case of such a conventional fluid-filled vibration-isolating bushing, as mentioned above, good damping is not possible for input vibration in the frequency range (tuning frequency range) set for the orifice. However, it is difficult to say that a good vibration isolation function can be obtained against input vibrations in other frequency ranges, especially for inputs in a frequency range higher than the tuning frequency range of the orifice. Regarding vibrations, there was a problem in that the incompressible fluid became difficult to flow through the orifice, and the vibration damping function was actually reduced.

(Solution Means) The present invention was made against the background of the above, 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 cylindrical member, (b) a sealing sleeve disposed concentrically or eccentrically on the outside of the inner cylindrical member, and (c) a sealing sleeve fitted on the outer peripheral surface of the sealing sleeve. an outer cylindrical member; (d) a rubber elastic body interposed between the seal sleeve and the inner cylindrical member to connect them; and (e) a rubber elastic body having a pocket portion opened on the outer peripheral surface; and (e) the seal sleeve. and (f) a hollow space penetrating in the direction of the axis of the bush provided between the inner cylinder member and the inner cylindrical member at a portion not connected by the rubber elastic body; (g) a pressure receiving chamber formed by fluid-tightly closing the seal sleeve with the outer cylinder member and into which vibrations to be damped are input; and (g) a pressure receiving chamber provided between the seal sleeve and the inner cylinder member. (h) a predetermined incompressible chamber sealed in the equilibrium chamber and the pressure receiving chamber; and (h) a predetermined incompressibility chamber enclosed in the equilibrium chamber and the pressure receiving chamber. (i) an orifice that allows the equilibrium chamber and the pressure receiving chamber to communicate with each other; (j) an orifice provided in the pressure receiving chamber and extending radially outward from the bottom of the pocket portion; a stopper portion having a predetermined height; and (k) a lateral extending portion extending laterally from the distal end portion of the stopper portion and forming a predetermined narrowing portion between the stopper portion and the inner wall of the pressure receiving chamber. The reason lies in the fact that it is structured to include the following.

(Operation/Effect) According to the fluid-filled vibration-isolating bushing according to the present invention, like the conventional fluid-filled vibration-damping bushing, by setting the tuning frequency of the orifice to a low frequency, the vibration damping bushing flowing through the orifice is set to a low frequency. Based on the inertial mass effect of the compressible fluid or the liquid column resonance effect, it is possible to satisfactorily attenuate low frequency and large amplitude vibrations input in the opposite direction between the pressure receiving chamber and the through space in the bush axis direction. It becomes possible.

On the other hand, as mentioned above, 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 bush axis direction is of high frequency and small amplitude, ,
It becomes difficult for an incompressible fluid 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,
This is because the incompressible fluid is allowed to flow in the radial direction of the bush through the constricted portion formed between the lateral extending portion provided at the distal end portion of the stopper portion and the inner wall of the pressure receiving chamber. By setting (tuning) the length and cross-sectional area of the constriction to correspond to a high frequency, the inertial mass effect or liquid column resonance effect of the incompressible fluid flowing through the constriction can be set. This makes it possible to effectively block high-frequency, small-amplitude input vibrations.

In other words, according to the fluid-filled vibration-isolating bushing according to the present invention, low-frequency, large-amplitude vibrations input in the radial direction of the bushing 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 similar to the conventional fluid-filled vibration isolating bushing. Based on the inertial mass effect or liquid column resonance effect of the incompressible fluid flowing through the constriction formed between the Therefore, it is possible to exhibit a vibration damping function superior to the conventional one against input vibration in the bush radial direction.

Moreover, according to the present invention, a space penetrating in the direction of the axis of the bushing is formed in a portion between the seal sleeve and the inner cylindrical member that are not connected by the rubber elastic body. It is said that by using a bushing that is precompressed in the radial direction, it is possible to effectively prevent excessive tensile force from acting on the rubber elastic body, thereby improving the durability of the rubber elastic body and, by extension, the bushing. There are also advantages.

Further, according to the present invention, a stopper portion is provided in the pressure receiving chamber, and the tip of the stopper portion is brought into contact with the outer cylinder member when the inner cylinder member and the outer cylinder member are displaced over a certain level. , excessive displacement between the inner cylinder member and outer cylinder member,
As a result, excessive displacement between the predetermined mounting shaft and the cylindrical holder, which are connected to each other in a vibration-proof manner by such a bushing, can be effectively prevented based on their contact, and based on their contact, the rubber elastic body It effectively prevents excessive compression deformation and improves the durability of the rubber elastic body.
Another advantage is that the durability of the bushing can be improved.

(Example) In order to clarify the present invention more specifically, below is an example in which the present invention is applied to a cylindrical engine mount used for anti-vibration support of a power unit of a FF (front engine/front drive) vehicle. Embodiments thereof will be described in detail based on the drawings.

First, in FIGS. 1 to 3, reference numerals 10 and 16 denote a cylindrical inner metal fitting as an inner cylinder member and a cylindrical outer metal fitting as an outer cylinder member, respectively. They are arranged with a certain amount of eccentricity, and are connected to the elastic bodies by a substantially semi-cylindrical rubber elastic body 14 interposed between them. The engine mount of this embodiment is fitted onto the outer circumferential surface of the outer cylindrical metal fitting 16 into a cylindrical holding part on the power unit side including the engine or on the vehicle body side, while the inner cylindrical metal fitting 16
The power unit is attached to the mounting shaft on the vehicle body side or the power unit side through the inner hole 18 of the power unit, so that the power unit is supported against vibrations in relation to the vehicle body.

Here, the rubber elastic body 14 is interposed between the two metal fittings 10 and 16 on the side where the separation distance in the eccentric direction between the inner cylinder metal fitting 10 and the outer cylinder metal fitting 16 is large. 16, a space 3 with a substantially arcuate cross-section is provided in the portion where the eccentric distance between the holes 3 and 16 is smaller, penetrating in the axial direction of the mount.
4 is formed. And the rubber elastic body 14
When the power unit is installed, the inner cylindrical metal fitting 10 and the outer cylindrical metal fitting 16 are compressed and deformed in the eccentric direction thereof, so that when the power unit is installed,
The inner cylindrical metal fitting 10 and the outer cylindrical metal fitting 16 are arranged substantially concentrically.

Further, the rubber elastic body 14 is integrally vulcanized and bonded to the outer circumferential surface of the inner cylindrical fitting 10 on its inner circumferential surface, and the seal sleeve 12 is attached to the outer circumferential surface in a state that includes the cavity 34. It is integrally vulcanized and bonded. And this seal sleeve 12
The outer cylindrical fitting 1 is fluid-tightly fitted to the outer peripheral surface of the outer cylindrical fitting 1
6 are arranged.

As shown in FIGS. 4 to 7, the seal sleeve 12 fixed to the outer circumferential surface of the rubber elastic body 14 is located opposite to the inner cylinder fitting 10 in the eccentric direction of the fittings 10 and 16. A pair of windows 20 and 22 are formed on the outer peripheral surface of the seal sleeve 12, and a pair of circumferential orifice grooves 2 are formed on the outer peripheral surface of the seal sleeve 12, connecting the windows 20 and 22.
4 and 26 are formed. Furthermore, the outer cylinder metal fitting 16 excluding the openings of those orifice grooves 24 and 26
A sealing rubber layer 30 having a predetermined thickness and having sealing lips 28, 28 at both ends in the axial direction is provided on the outer peripheral surface of the rubber elastic body 14 by vulcanization molding integrally with the rubber elastic body 14.

On the other hand, the rubber elastic body 14 has
As shown in the figure, the sealing sleeve 1
A pocket portion 32 of a predetermined depth is formed in a state where it opens into the window portion 20 of No. 2. In addition, the space 3
The part of the seal sleeve 12 facing the window 22 of the seal sleeve 12 is provided with a thin wall part that easily expands and deforms, with both end parts separated in the mount circumferential direction of the seal sleeve 12 being closed from the inside. The rubber elastic membranes 36 and 38 are integrally vulcanized and bonded to each other, so that the pair of recesses 4 of a predetermined depth are opened in the window 22 of the seal sleeve 12.
0,42 are formed. As is clear from FIGS. 4 and 5, the window portion 22 of the seal sleeve 12 between the recesses 40 and 42 is made of rubber having a predetermined thickness that is integrally formed with the rubber elastic membranes 36 and 38. covered with layers.

Here, as described above, by fluid-tightly fitting the outer cylindrical fitting 16 to the seal sleeve 12, the windows 20, 22, and eventually the pocket 32 and the recesses 40, 42 are closed. The openings are each fluid-tightly closed to form a pressure receiving chamber 44 and a pair of equilibrium chambers 46, 48, each of which uses the pocket portion 32 and the spaces within the recesses 40, 42 as fluid storage spaces. Further, the openings of the orifice grooves 24 and 26 are fluid-tightly closed by the outer cylindrical fitting 16, so that the orifice 50 communicates the pressure receiving chamber 44 and each equilibrium chamber 46, 48.
52 is formed. Further, here, the fitting operation of the outer cylinder fitting 16 to the seal sleeve 12 is performed in a predetermined incompressible fluid, so that the pressure receiving chamber 44 and each equilibrium chamber 46, 48
A predetermined incompressible fluid such as water, alkylene glycol, polyalkylene glycol, or low molecular weight polymer is sealed inside.

The outer cylindrical metal fitting 16 is fixed to the seal sleeve 12 by drawing in all directions. Also,
After the outer cylinder fitting 16 is fitted, the engine mount of this embodiment is passed through a predetermined die to set its outer diameter to a desired size. Furthermore, the orifice 5
The cross-sectional area and length of the orifices 50 and 52 are set (tuned) to correspond to vibrations in a predetermined low frequency range, and as a result, the orifices 50 and
Based on the inertial mass effect or liquid column resonance effect of the incompressible fluid flowing through the orifices 52 or located there, vibrations in a low frequency range corresponding to the tuning frequency of the orifices 50 and 52 are well damped. It is becoming more and more popular.

By the way, as shown in FIGS. 4 to 6, on the outer circumferential surface of the inner cylindrical fitting 10, there is a fitting 10, which is located in the center in the axial direction and extends in the longitudinal direction.
16, the stopper fitting 54 in the form of a longitudinal block with a predetermined length is inserted into the central hole 5.
It is press-fitted and fixed at 6. Both ends of the stopper metal fitting 54 in the longitudinal direction are made to protrude into the pocket portion 32 and the cavity 34 at a predetermined height, so that both ends of the stopper metal fitting 54 are Due to the contact with the inner circumferential surface of the outer cylindrical fitting 16, excessive relative displacement between the inner cylindrical fitting 10 and the outer cylindrical fitting 16 in the eccentric direction is prevented.

That is, here, both longitudinal ends of the stopper metal fittings 54 are used to restrict excessive relative displacement between the inner cylinder metal fitting 10 and the outer cylinder metal fitting 16, and furthermore, to restrict excessive relative displacement between the power unit and the vehicle body. Based on the abutment of the stopper portion 58 against the outer cylinder metal fitting 16, excessive compressive deformation of the rubber elastic body 14 is well prevented, and Based on the contact of the stopper portion 60 with the outer cylinder metal fitting 16, excessive tensile deformation of the rubber elastic body 14 is effectively prevented.

The surface of the stopper fitting 54 extending into the cavity 34 is covered with a cushioning rubber layer of a predetermined thickness that is molded integrally with the rubber elastic body 14.

Here, as shown in FIGS. 4 and 5, the pocket portion 32 (pressure receiving chamber 44)
A female screw hole 62 is formed in the distal end surface of the stopper portion 58 that extends inward, and a male screw hole 62 is screwed into the female screw hole 62, as shown in FIGS. 1 and 2. The screws 64 cause the outer peripheral edge to extend laterally around the stopper part 58, in other words, the outer peripheral edge protrudes from the side surface of the stopper part 58 by a predetermined distance in the mount axis direction and in the mount circumferential direction. In this state, a rectangular plate-shaped laterally extending member 66 having a substantially arcuate cross section is fixed.

In this embodiment, an annular narrowed portion 67 is formed between the outer peripheral edge of the side-extending member 66 and the inner wall of the pressure-receiving chamber 44 in a state substantially perpendicular to the eccentric direction of the metal fittings 10 and 16. Therefore, when the inner cylindrical fitting 10 and the outer cylindrical fitting 16 are moved relative to each other in their eccentric direction by vibration input, the pressure receiving chamber 4
The incompressible fluid within 4 is made to flow in the radial direction of the mount through the constriction 67.

The length of the narrowed portion 67 in the vibration input direction (the eccentric direction of both metal fittings 10 and 16) is:
(See FIGS. 1 and 2) and the cross-sectional area (area of the constriction portion 67 in the direction perpendicular to the vibration input direction) are set to correspond to a frequency higher than the tuning frequency of the orifices 50 and 52. As a result, the tuning frequency of the narrowed portion 67 is adjusted based on the inertial mass effect or liquid column resonance effect according to the relative flow of the incompressible fluid located in the narrowed portion 67 to the lateral extending member 66. Input vibrations in the corresponding high frequency range can be effectively blocked.

Further, as shown in FIGS. 1 and 2, the lateral extending member 66 includes a reinforcing metal fitting 68 fixed to the stopper portion 58 by a male screw 64, and an outer surface thereof. It consists of a buffer rubber layer 70 of a predetermined thickness that is integrally vulcanized with the buffer rubber layer 70, and a through hole 72 for screwing the male screw 64 into the female screw hole 62 is formed in the buffer rubber layer 70. .

Furthermore, as is clear from the above description, in this embodiment, the outer peripheral edge portion of the lateral extending member 66 that protrudes laterally from the side surface of the stopper portion 58 is connected to the pressure receiving chamber 4.
A lateral extending portion forms a narrowed portion 67 with the inner wall of the portion 4.

Therefore, according to the engine mount having such a structure, there is a gap between the inner cylinder fitting 10 and the outer cylinder fitting 16.
When low-frequency and large-amplitude vibrations in opposing directions between the pressure-receiving chamber 44 and the cavity 34 are input, the pressure-receiving chamber 44 and each equilibrium chamber 46,
48 through the orifices 50, 52, and the incompressible fluid flowing through or located therein is similar to conventional fluid-filled engine mounts. Based on the inertial mass effect of the fluid or the liquid column resonance effect, the low frequency and large amplitude vibrations are effectively damped.

On the other hand, if the vibrations input in the opposite direction between the pressure receiving chamber 44 and the cavity 34 are of high frequency and small amplitude, the incompressible fluid no longer flows into the orifices 50 and 5.
The incompressible fluid flows through the orifices 50, 52 from where it becomes difficult to flow through the orifices 2.
The reduction in dynamic spring constant that can be achieved by flowing through is almost impossible. 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 portion 67, the narrowed portion 67
Based on the inertial mass effect or liquid column resonance effect according to the relative flow action of the incompressible fluid on the side-extending member 66 located at 7, the high frequency and small amplitude vibrations can be effectively blocked. Become. In other words,
Compared to conventional fluid-filled engine mounts that do not have such a narrowed part 67, high-frequency
This greatly improves the effectiveness of blocking small amplitude vibrations.

As described above, the cylindrical engine mount according to the present embodiment can withstand low frequency and large amplitude vibrations input in the opposite direction between the pressure receiving chamber 44 and the cavity 34.
While it can exhibit good damping effect as before, it is effective against high-frequency and small-amplitude vibrations.
It is possible to exhibit a better isolation effect than in the past, and therefore it is possible to attenuate or isolate vibrations input in the radial direction of the mount more advantageously than in the conventional mount.

Further, in the engine mount of this embodiment, as described above, when the power unit is installed, the rubber elastic body 14 is compressed in the eccentric direction of the metal fittings 10 and 16, and the rubber elastic body 14 is compressed in the hollow space 34. A stopper portion 60 is provided that protrudes from the
Since excessive tensile force is effectively prevented from being applied to the rubber elastic body 14, there is an advantage that the rubber elastic body 14 and, by extension, the engine mount have excellent durability. Furthermore, the stopper portion 58 is extended into the pressure receiving chamber 44, and the rubber elastic body 14 is prevented from being excessively compressed and deformed based on the contact of the stopper portion 58 with the outer cylinder metal fitting 16. In this sense as well, there is an advantage that the rubber elastic body 14 and, by extension, the engine mount have excellent durability.

Furthermore, since the stopper portions 58 and 60 extend into the pocket portion 32 and the space 34, respectively, an advantage is that excessive displacement between the power unit and the vehicle body can be effectively prevented as described above. There is also.

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

For example, in the embodiment described above, 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 can also be constructed integrally with the stopper metal fitting 54. Further, the lateral extending portion forming the narrowed portion 67 with the inner wall of the pressure receiving chamber 44 does not need to extend to the side of the stopper portion 58 over the entire circumference of the stopper portion 58; It is also possible to form a narrowed portion 67 by providing a lateral extending portion so as to extend only in the mount circumferential direction (bush circumferential direction) from the side surface of 58 .

Further, in the embodiment described above, the recesses 40 and 42 constituting the equilibrium chambers 46 and 48 were formed with openings formed in each of the window portions 22 of the seal sleeve 12. , 48 can also be formed with mutually independent windows formed in the sealing sleeve 12 as openings, and the recesses 40, 42 of the equilibrium chambers 46, 4
It is also possible to form 8 as one equilibrium chamber, and furthermore, it is also possible to employ only one of the equilibrium chambers 46 and 48 as an equilibrium chamber.

Further, in the embodiment described above, the rubber elastic membranes 36 and 38 as thin wall portions forming the equilibrium chambers 46 and 48 were integrally attached to the seal sleeve 12, but the thin wall portions are not necessarily attached to the seal sleeve. They do not need to be glued together; the thin wall can be constructed separately from the sealing sleeve and mechanically attached to the sealing sleeve to form an equilibrium chamber. It is.

Further, in the embodiment described above, the inner tube fitting 10 and the outer tube fitting 16 are arranged eccentrically by a predetermined amount in the radial direction of the mount, but it is also possible to arrange them concentrically.

In addition, in the above embodiment, an example was described in which the present invention was applied to a cylindrical engine mount for a FF vehicle, but the present invention can also be applied to a cylindrical engine mount other than a cylindrical engine mount for a FF vehicle, such as a suspension bushing for an automobile. It can also be applied to vibration bushings and anti-vibration mounts.

Although not listed in detail, it goes without saying that the present invention can be implemented with various changes, modifications, improvements, etc. without departing from the spirit thereof.

[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. 2 and 3 are a cross-sectional view and a cross-sectional view, respectively, of FIG. FIG. 4 is a sectional view corresponding to FIG. 1 showing an integrally vulcanized product of the rubber elastic body in the engine mount of FIG. 1;
5, 6 and 7 are a cross-sectional view, a cross-sectional view and a cross-sectional view in FIG. 4, respectively.
FIG. 10... Inner tube fitting (inner tube member), 12... Seal sleeve, 14... Rubber elastic body, 16... Outer tube fitting (outer tube member), 20, 22... Window, 24,
26... Orifice groove, 32... Pocket part, 3
4...Vacancy, 36, 38...Rubber elastic membrane (thin wall part), 40, 42...Recess, 44...Pressure receiving chamber, 4
6, 48... Equilibrium chamber, 50, 52... Orifice, 54... Stopper fitting, 58, 60... Stopper part, 66... Laterally extending member, 67... Narrowing part, 68... Reinforcement fitting, 70...Buffer rubber layer.

Claims (1)

[Scope of Claims] 1. An inner cylindrical member; a seal sleeve disposed concentrically or eccentrically on the outside of the inner cylindrical member; an outer cylindrical member fitted onto the outer peripheral surface of the seal sleeve; and the seal. a rubber elastic body interposed between the sleeve and the inner cylindrical member to connect them; and a rubber elastic body having a pocket portion opened on the outer circumferential surface; and a rubber elastic body between the seal sleeve and the inner cylindrical member. a hollow space penetrating in the direction of the axis of the bush provided in a portion not connected with the pocket part of the rubber elastic body, the opening of which is fluid-tightly closed by the outer cylindrical member; At least a portion of the formed pressure receiving chamber into which vibrations to be damped are input, and the through space provided between the seal sleeve and the inner cylinder member with a thin wall portion that can be easily bulged and deformed. an equilibrium chamber defined and formed; a predetermined incompressible fluid sealed in the equilibrium chamber and the pressure receiving chamber; an orifice that allows the equilibrium chamber and the pressure receiving chamber to communicate with each other; and an orifice within the pressure receiving chamber. A stopper portion of a predetermined height is provided to extend radially outward from the bottom of the pocket portion, and a stopper portion is provided to extend laterally from a distal end portion of the stopper portion, and the stopper portion is provided to extend radially outward from the bottom of the pocket portion, and the stopper portion is provided to extend laterally from the tip side of the stopper portion, and 1. A fluid-filled vibration-isolating bushing comprising: a lateral extending portion forming a predetermined narrowed portion with an inner wall of a chamber.