JP2002303348A - Fluid sealed cylindrical vibration control device and producing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an orifice passage having a long passage on an outer peripheral part of a main body rubber elastic body directly without using another orifice member and to effectively reduce a spring property to a direction crossing a main vibration input direction at right angles and improve vibration resistance when vibrated around an axis. SOLUTION: A recessed groove 38 forming the orifice passage 50 communicating with two fluid chambers 48 provided on an outer peripheral part of the main body rubber elastic body 16 contains an axial direction groove part 38a extending to an axial direction. A wall surface along an opening direction of both side wall surfaces of the axial direction groove part 38a of the recessed groove 38 forming the orifice passage 50 is constituted as an inclined surface 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical fluid-filled type vibration damping device for obtaining a vibration damping effect based on the flow action of a fluid sealed therein, and an advantageous method of manufacturing the same. The present invention relates to a structure capable of realizing both high attenuation characteristics and improved durability in such a device at low cost.

[0002]

2. Description of the Related Art Conventionally, a cylindrical outer member and a cylinder of such an outer member have been used as one type of a vibration isolator which is interposed between members constituting a vibration transmission system to connect the two members with vibration isolation. Arranged to extend in the axial direction so as to penetrate the inside,
BACKGROUND ART A tubular vibration isolator having a structure in which a tubular or rod-shaped inner member is connected to a main rubber elastic body is known. For example, a suspension bush for an automobile, an engine mount,
Used for differential mount, body mount, etc. In addition, in order to obtain a better vibration damping effect, a plurality of pockets provided so as to be opened on the outer peripheral surface of the main rubber elastic body are covered with the outer member, so that an incompressible fluid is enclosed. A plurality of fluid chambers are formed, and the fluid chambers are connected by an orifice passage, and a fluid-filled cylindrical vibration damping device utilizing the resonance action of the fluid caused to flow through such an orifice passage is also provided. Various proposals have been made.

In such a fluid-filled cylindrical vibration damping device, the orifice passage is sufficiently provided in order to improve the degree of freedom in tuning vibration damping characteristics based on the fluid flow action and to improve the vibration damping effect. It is desirable to make
Therefore, as shown in Japanese Utility Model Laid-Open Publication No. 1-3141,
It has been proposed to assemble a separate orifice member to form a long orifice passage. However, adopting such a configuration in which a separate orifice member is assembled increases the number of parts, complicates the structure, and causes problems such as deterioration in manufacturability and increase in manufacturing cost. It is.

On the other hand, JP-A-9-264371 and JP-A-2000-170823 disclose the outer peripheral portion of a main rubber elastic body located between pocket portions each providing a plurality of fluid chambers. A fluid-filled cylindrical vibration damping device having a structure in which an orifice passage is formed by forming a concave groove extending between openings and covering the concave groove with an outer member has also been disclosed. . By adopting such an orifice passage forming structure, it is not necessary to use a separate orifice member to constitute the orifice passage, and therefore, a fluid-filled cylindrical vibration isolator can be configured with a small number of parts. There is an advantage that becomes possible.

In a relatively small fluid-filled cylindrical vibration damping device such as a suspension bush, a direction orthogonal to a main vibration input direction which is a facing direction of two corresponding fluid chambers (pocket portions). In order to improve the torsional durability of the main rubber elastic body when the inner member is twisted around its axis, the outer peripheral surface of the main rubber elastic body is lowered. In a pair of supporting bowls that support the inner member and that are formed by circumferential side walls of two adjacent pockets provided so as to be opened, a structure in which the circumferential side walls of the pockets are hollowed out, etc. It is required to secure a long effective free length in the radial direction of the main rubber elastic body by adopting the above.

However, in a fluid-filled cylindrical vibration isolator having a structure in which a concave groove is formed directly on the outer peripheral portion of the main rubber elastic body, the concave groove is formed by vulcanization molding of the main rubber elastic body. At the same time, when formed, a general two-piece mold, for example, the main rubber elastic body is opened in the direction in which the pocket portion forming the fluid chamber opens in the main rubber elastic body, and the main rubber elastic body located between the pocket portions When molding is performed using a general two-piece mold having a mold mating surface in the circumferential center of the outer peripheral portion, a groove in a direction parallel to the mold opening direction, in other words, the main body rubber A groove extending in the circumferential direction at the outer peripheral portion of the elastic body can be molded,
In the groove extending in the axial direction perpendicular to the mold opening direction,
Of the left and right wall surfaces of the concave groove portion, the wall surface closer to the fluid chamber, i.e., the wall surface on the front side in the mold opening direction, the projection of the molding die that forms the concave groove is caught when opening the mold. In addition, there is a problem that the molded main body rubber elastic body cannot be removed from the molding die, and it is difficult to form such an axial groove.

[0007]

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an orifice passage having a long orifice passage length without using a separate orifice member. To be able to be formed directly on the outer peripheral portion of the main rubber elastic body, and to be able to effectively lower the spring characteristics in the direction orthogonal to the main vibration input direction, and further twisted around the axis. It is an object of the present invention to provide a fluid-filled cylindrical vibration isolator capable of advantageously improving the torsional durability at the time, and an advantageous manufacturing method thereof.

[0008]

In order to solve such technical problems, first, in the present invention, a cylindrical outer member and an outer member are arranged so as to penetrate through the inside of the outer member. The inner member extending in the axial direction is connected to the main rubber elastic body having a cylindrical shape as a whole, while the inner member is located at both radially opposite sides sandwiching the main member in the main vibration input direction. By covering the first pocket portion and the second pocket portion provided to be open on the outer peripheral surface with the outer member, two fluid chambers filled with an incompressible fluid are formed. A groove extending across the opening of the first and second pockets is formed in an outer peripheral portion of the main rubber elastic body located between two fluid chambers, and the groove is formed by the outer member. The fluid chambers are interconnected by covering. In a fluid-filled cylindrical vibration isolator having a orifice passage formed therein, the concave groove includes at least an axial groove extending in an axial direction of the main rubber elastic body, and both sides providing the axial groove. Of the side walls, the side wall portion located closer to one of the two fluid chambers is inclined toward the one fluid chamber so that the axial groove portion is radially outward of the main rubber elastic body. A fluid-filled cylindrical vibration isolator characterized by having a structure having an opening that expands toward the main body.

Therefore, in such a fluid-filled cylindrical vibration damping device according to the present invention, an orifice passage connecting between two opposed fluid chambers is formed by the outer member and the main rubber elastic body. Therefore, it is not necessary to use special parts for forming the orifice passage, and the man-hour required for assembling can be reduced. As a result, such a fluid-filled cylindrical vibration isolator can be used. Of course, it has a feature that the production cost of the device can be advantageously reduced. Of course, the side wall of the groove forming the orifice passage that extends in the axial direction of the main rubber elastic body is closer to the fluid chamber side. In order to obtain the main rubber elastic body having such a groove, the side wall portion on the side is formed as an inclined surface expanding outward in the radial direction. A general two-parting method having a mold matching surface at a central portion in the circumferential direction of the orifice disposition portion and performing mold opening in directions in which the first pocket portion and the second pocket portion forming the fluid chamber are opened. In the case where a molding die is used, a projecting portion of the mold for molding a groove extending in the axial direction provided at the orifice arrangement site of the outer peripheral portion of the main rubber elastic body, which is generated when the two-part molding die is opened, As a result, the engagement with the molded main body rubber elastic body (axial groove) can be eliminated by the elastic deformation of the rubber on the inclined wall surface, and the mold can be removed without any problem. is there.

[0010] As a result, the concave groove providing the orifice passage connecting the two fluid chambers at the outer peripheral portion of the main rubber elastic body can be configured to include the axial groove extending in the axial direction of the main rubber elastic body. From the above, it is possible to adopt a concave groove arrangement mode in which the length of the orifice passage is longer in the limited area of the orifice arrangement portion on the outer peripheral portion of the main rubber elastic body. The width of the orifice passage length and the selection of parameters for the cross-sectional area for obtaining the vibration damping characteristics can be advantageously expanded, and the degree of freedom in design can be advantageously increased.

In addition, since it has become possible to employ a two-piece mold having the above-described mold opening direction, the fluid-filled cylindrical vibration isolator according to the present invention has the following features.
By digging the circumferential side wall portions of the pocket portions, which are constituted by a main rubber elastic portion located between the first pocket portion and the second pocket portion, the pocket portions on both sides are formed. The effective free length of the support bowl portion of the inner member of the main rubber elastic body constituted by the circumferential side wall portion can be increased, and as a result, the main rubber elastic body when the inner member is twisted around the axis. The feature that the torsional durability can be advantageously improved can also be realized.

According to one preferred embodiment of the fluid-filled cylindrical vibration damping device according to the present invention, the concave groove extends in the circumferential direction of the main rubber elastic body together with the axial groove. The groove is configured to include the circumferential groove, and the axial groove and the circumferential groove are alternately combined to form a concave groove arrangement structure having a rectangular waveform bent shape in a plane form. Thus, at the orifice disposition portion of the outer peripheral portion of the main rubber elastic body, since the orifice passage is formed by the concave groove which is bent and extended alternately in the axial direction and the circumferential direction, the recess extending only in the circumferential direction is formed. An advantage is that it is possible to obtain a much longer passage length than connecting the fluid chambers with the orifice passage formed by the groove, and it is possible to further improve the loss peak characteristic of the whole vibration isolator. is there.

According to another preferred embodiment of the fluid-filled cylindrical vibration isolator according to the present invention, the cross-sectional area of the axial groove formed by inclining one of the side wall portions is the concave portion. The cross-sectional area of the groove other than the axial groove is equal to that of the groove. Thereby, the flow of the incompressible fluid flowing in the orifice passage is not obstructed,
The vibration damping effect by the flow action of the incompressible fluid can be more effectively exerted.

In the present invention, in order to advantageously obtain the above-mentioned fluid-filled cylindrical vibration isolator according to the present invention, the inner member and the main rubber elastic body are integrally vulcanized and formed. In addition to the above, the integrally vulcanized molded product has a dividing surface extending in the axial direction at a circumferential central portion of an orifice arrangement portion of the outer peripheral portion of the main rubber elastic body, and the first vulcanized product provided on the main rubber elastic body A fluid-filled cylindrical vibration isolator characterized by being vulcanized by using a two-part mold that is opened in the direction in which the one pocket part and the second pocket part face each other. The method of making is also the gist.

According to the manufacturing method according to the present invention, the integrally vulcanized molded product, specifically, the main rubber elastic body is provided with the first pocket portion and the second pocket portion provided in the main rubber elastic body. Since the vulcanization molding is performed by using a general two-piece molding die that is opened in a direction opposite to the vulcanization molding, the cost required for the vulcanization molding of such a main rubber elastic body is effectively reduced. At the same time as vulcanization molding,
Since the concave groove is also formed at the same time, there is no need to post-process a separately molded member, so that the structure can be simplified and the productivity can be advantageously improved.

In addition, of the side walls of the groove forming the orifice passage, which extend in the axial direction of the main rubber elastic body, the side wall portion on the side closer to the fluid chamber side, that is, the wall surface in the direction in which the mold is opened has a diameter. The projection of the mold that forms the axially extending groove provided at the orifice arrangement site on the outer peripheral portion of the main rubber elastic body from the inclined surface that expands outward in the direction When the mold is opened, even if the orifice is caught on the molded rubber elastic body, the clogging can be eliminated by the elastic deformation of the rubber on the inclined wall surface. Thus, the mold can be opened without causing the problem described above.

Further, a two-piece mold for molding such an integrally vulcanized molded product (main rubber elastic body) is opened in a direction opposite to a first pocket portion and a second pocket portion providing a fluid chamber. The main body constituted by the circumferential side wall portions of the pocket portions on both sides by cutting the circumferential side wall portion between the first pocket portion and the second pocket portion, etc. It is possible to increase the effective free length of the inner member support bowl portion of the rubber elastic body, and the torsional durability of the main rubber elastic body when the inner member is twisted around the axis,
It can be advantageously improved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

First, FIGS. 1 and 2 show an automobile suspension bush 10 according to an embodiment of the present invention embodied in a compression rod bush. The suspension bush 10 is configured such that an inner cylinder fitting 12 as an inner member and an outer cylinder fitting 14 as an outer member are elastically connected by a main rubber elastic body 16. While the outer cylinder 14 is attached to the body, the suspension rod (compression rod) 18 is inserted and fixed to the inner cylinder 12, so that the suspension rod can be supported by the body in vibration isolation. It has become.

More specifically, the inner cylinder fitting 12 has a bottomed hollow cylindrical shape in which one end of a straight pipe is closed, and a suspension rod 18 is inserted into the hollow hole from the open end side. It is to be inserted. The axial end on the opening side into which such a suspension rod 18 is inserted has a tapered shape that slightly expands outward, whereby the suspension rod 18 is inserted into the hollow hole. The insertion workability at the time of insertion is improved.

A large-diameter cylindrical metal sleeve 20 is provided radially outward on the outer peripheral side of the inner cylindrical fitting 12.
It is arranged substantially coaxially in a state surrounding the inner tube fitting 12. Then, a main rubber elastic body 16 is interposed between the radially opposed surfaces of the inner cylindrical metal fitting 12 and the metal sleeve 20, and the inner cylindrical metal fitting 1 is attached by the main rubber elastic body 16.
2 and the metal sleeve 20 are elastically connected. That is, the main rubber elastic body 16 has a substantially thick cylindrical shape, the inner peripheral surface of which is joined to the outer peripheral surface of the inner cylindrical fitting 12, and the outer peripheral surface of which is the metal sleeve 2.
Thus, the structure is such that it is bonded to the inner peripheral surface of the “0”. In this embodiment, in the molding cavity in which the inner cylinder fitting 12 and the metal sleeve 20 are set at predetermined positions,
By filling the rubber material and performing vulcanization molding, FIG.
5, the metal sleeve 20 is bonded to the outer peripheral surface of the main rubber elastic body 16 by vulcanization, while the inner cylindrical surface of the main rubber elastic body 16 is The outer peripheral surface of the metal fitting 12 is vulcanized and bonded, and a thin rubber portion integrally formed with the main rubber elastic body 16 is vulcanized and bonded to the inner peripheral surface of the inner cylindrical metal fitting 12. ing. In other words, the inner cylinder fitting 12 is configured so as to be entirely covered with the rubber elastic body composed of the main rubber elastic body 16 and the thin rubber portion.

The outer peripheral surface of the main rubber elastic body 16 constituting the integrally vulcanized molded product 22 has radially opposite portions sandwiching the inner cylindrical fitting 12 in the main vibration input direction (vertical direction in FIG. 4). In the above, a pair of pocket portions 24 as pocket-shaped recesses opening outward are formed symmetrically. Further, a pair of window portions 26 extending symmetrically in the radial direction with a length of not more than half a circumference are formed in the metal sleeve 20 at portions facing each other in one radial direction. The pockets 24, 24 of the main rubber elastic body 16 are opened radially outward through the windows 26, 26, respectively. In addition, each pocket part 2
A stopper 28 protrudes radially outward from the center of the bottom surface of the pocket portion 24 to suppress the operating range of the inner cylindrical fitting in the vibration input direction. Are not provided, and are provided respectively.
The stopper 28 is made of a rubber elastic body formed so as to cover the entire stopper block fixed to the inner cylinder fitting 12, is formed integrally with the main rubber elastic body 16, and is vulcanized and adhered to the stopper block. Have been.

Further, the integrally vulcanized molded product 22 obtained by vulcanization molding as described above is subjected to drawing processing such as octagonal drawing on the metal sleeve 20 to reduce the diameter. . As a result, in the main rubber elastic body 16, the tensile stress due to shrinkage during vulcanization molding is reduced or eliminated, and by further applying pre-compression, etc., the adhesive strength between each bracket and the main rubber elastic body is increased, and the durability is improved. Performance can be improved. In the present embodiment, the metal sleeve 2
0 is an axially opposite end portion 3 as shown in FIG.
Each of the metal sleeves 20 is directly exposed to the outside without being covered with a rubber layer or the like, so that the metal sleeve 20 can be easily and advantageously drawn. ing.

Furthermore, as shown in FIG. 5, the metal sleeve 20 has a central portion 32 in the axial direction having a smaller diameter than the both end portions 30 in the axial direction. In the outer peripheral portion of the pocket 22, wide circumferential grooves 34, 34 that open in the outer peripheral surface and extend in the circumferential direction are formed so as to straddle between both ends in the circumferential direction of the pocket portions 24, 24. Further, in the circumferential grooves 34, 34, the main rubber elastic body 16 is provided with the window 26
An orifice disposition portion 36 is formed so as to be filled into the circumferential groove 34 and to be integrated with the main rubber elastic body 16. In addition, such an orifice disposition portion 36 is surrounded by a metal sleeve 20 so that the orifice disposition portion 36 is substantially separated from the outer peripheral portion of the main rubber elastic body 16 by the metal sleeve 20. , The transmission of stress from the main rubber elastic body 16 to the orifice arrangement portion 36 can be effectively prevented.

Here, the orifice disposing portion 36 is
As shown in FIGS. 3 to 5, the peripheral groove 34 formed in the metal sleeve 20 is substantially completely filled with a rubber elastic body material, and its outer peripheral surface (surface) is formed of a metal sleeve. It is substantially flush with the outer peripheral surfaces of the axially opposite end portions 30, 30 of 20. And this orifice arrangement part 3
6, as shown in FIG. 3, a rectangular wave-shaped concave groove 38 that extends alternately in the circumferential direction and the axial direction,
It is formed. That is, the concave groove 38 is configured such that the axial groove portion 38a extending in the axial direction and the circumferential groove portion 38b extending in the circumferential direction are arranged in a rectangular wave shape.
It is constructed in combination and extends across both windows 26, 26 of the metal sleeve 20 and comprises two pockets 2
4, 24 are connected. In this embodiment, as shown in FIGS. 1 and 4, among the wall surfaces on both sides of the axial groove portion 38 a extending in the axial direction of the concave groove 38, the wall surface on the side closer to the pocket portion 24 is The inclined surface 40 expands radially outward. In addition, this inclined surface 40
The inclination angle of is not particularly limited, and vulcanization molding of the integrally vulcanized molded product 22 is performed by a two-part molding die described later, and when the molded product is die-cut, a concave groove is formed. The angle is set to such an extent that the orifice arrangement portion 36 does not break even if the axial groove portion 38a is hooked with respect to the molding die.

In this embodiment, the cross-sectional area of the concave groove 38 formed by alternately combining the two types of grooves 38a and 38b extending in the axial direction and the circumferential direction is determined at any position (part). The cross-sectional area of the axial groove 38a and the cross-sectional area of the circumferential groove 38b are configured to be the same even when cut. In addition, such a groove 38 is provided here with the orifice disposition portion 36.
Of the entire thickness of the metal sleeve 20, that is, a depth substantially reaching the metal sleeve 20. However, the dimensions such as the cross-sectional area and depth of the concave grooves 38 are not particularly limited, and the desired vibration damping characteristics can be determined by using a known equation for giving a resonance frequency in the orifice passage. A cross-sectional area and a passage length are obtained, and those values are appropriately adopted.

Then, the outer tube fitting 14 is externally inserted into the integrally vulcanized molded product 22 having such a structure, and is fitted and fixed. In addition, such an outer tube fitting 14 is
As a whole, it has a large-diameter cylindrical shape, the central portion in the axial direction is a small-diameter portion protruding toward the inner peripheral surface over a predetermined width, and one end in the axial direction is radially inward. It is bent to form an inner flange. A thin seal rubber layer 42 is vulcanized and adhered to the inner peripheral surface substantially all over, and the outer peripheral surface is formed into a shape conforming to the body shape of an assembly destination (not shown). Rubber elastic body is vulcanized and bonded.

By the way, the outer cylinder fitting 14 having such a structure is used.
Is a primary processed product 46 having a straight tubular cylindrical shape having no small-diameter portion at the central portion in the axial direction as shown in FIG. 6, for example.
It will be prepared as. And the primary processed product 4
6, when the integrally vulcanized molded product 22 is inserted as shown in FIG.
A plurality of seal lips 44 extending continuously in the circumferential direction are provided integrally with the seal rubber layer 42 at a portion where the seal rubber layer 42 contacts. It should be noted that such a primary processed product 46 of the outer tube fitting 14 is placed in a predetermined molding cavity.
4 is set, rubber is filled in the molding cavity, and vulcanization molding is performed, whereby the seal rubber layer 42 and the rubber elastic body are vulcanized and adhered to the inner and outer peripheral surfaces of the outer cylinder fitting 14. Obtained as an integrally vulcanized molded product.

Then, as shown in FIG. 7, the integrally vulcanized molded product 2
2 is inserted, the central portion in the axial direction of the outer tube fitting 14 is reduced in diameter by applying drawing such as octagonal drawing, and the outer peripheral portion of the integrally vulcanized molded product 22, that is, the metal sleeve 20 is formed.
And the orifice disposing portion 36 is pressed against the seal rubber layer 42 adhered to the inner peripheral portion of the outer tube fitting 14, so that the outer tube fitting 14 is externally fitted and fixed to the integrally vulcanized molded product 22, and As a result, the suspension bush 10 is obtained.

Thus, as shown in FIGS. 1 and 2,
By covering the windows 26, 26 of the metal sleeve 20 with the outer tube fitting 14, a pair of fluid chambers 48, 48 in which an incompressible fluid is sealed inside the pockets 24, 24 are formed. It becomes. Further, the outer tube fitting 1
4 and the outer peripheral surface of the orifice arrangement portion 36
The groove 38 (the axial groove 38a and the circumferential groove 38b) is covered with the outer tube fitting 14 by the close contact through the orifice 2, and the orifice passage 50 that communicates the pair of fluid chambers 48 with each other. Is formed. The sealing of the incompressible fluid can be performed in the same manner as in the related art, for example, by assembling the integrally vulcanized molded product 22 and the outer cylinder fitting 14 in such a fluid. Become. Alternatively, after assembling the integrally vulcanized molded product 22 and the outer tube fitting 14, an injection needle is pierced and penetrated into the main rubber elastic body 16 constituting the wall of the fluid chamber 48, and air suction and non-suction are performed through the injection needle. It is also possible to perform an injection of a compressible fluid. After assembling the integrally vulcanized molded product 22 and the outer cylinder 14, a through-hole is pre-drilled or rear-pierced into the outer cylinder 14 constituting the outer peripheral wall of the fluid chamber 48. There is no problem even if air is sucked and an incompressible fluid is injected therethrough.

Here, the integrally vulcanized molded product 22 constituting the suspension bush 10 as described above advantageously extends in the axial direction at the circumferential center of the orifice arrangement portion 36 as shown in FIG. The vulcanization is carried out by using two-part molds 52 and 54 which have mold matching surfaces and are mold-opened in the direction opposite to the pockets 24 and 24 provided in the main rubber elastic body 16 of the integrally vulcanized molded product 22. It is desirable that it be molded.

Specifically, first, such a mold 5
After setting the inner tube fitting 12 and the metal sleeve 20 at predetermined positions in the molding cavities 2, 54, vulcanization molding is performed by filling the molding cavities with rubber. Then, after that, when the mold is opened and the molded integral vulcanized molded product 22 is removed from the mold, an axial groove 38a formed in the orifice arrangement portion 36 and extending in the axial direction of the concave groove 38 is provided. In this case, there is a possibility that the mold may be caught by a mold (specifically, a mold for forming the axial groove 38a) for forming the concave groove 38 provided in the molds 52 and 54. Of the two side wall surfaces forming the axial groove portion 38a, the side wall surface closer to the pocket portion 24, in other words, the side wall surface in the direction in which the mold is opened is the inclined surface 40. The stress in the mold opening direction, which acts when the axial groove forming portion 56 provided on the forming dies 52 and 54 passes through the outer circumferential portion 58 from the axial groove 38a of the orifice arrangement portion 36, is advantageously reduced. It will be done. As a result, the hook between the axial groove forming portions 56 of the forming dies 52 and 54 and the circumferential outer portion 58 of the orifice disposing portion 36 is effectively absorbed by the elastic deformation of the rubber. The mold is opened without causing a problem such as breakage in the orifice arrangement portion.

Further, in obtaining the integrally vulcanized molded product 22, the use of the molding dies 52, 54 which are opened in the direction in which the pockets 24, 24 open as described above allows the two pockets 24 to be opened. , 24 can be recessed radially inward from the end face of the window 26, and the rubber elastic body is formed by the circumferential side walls of the two pockets. The effective free length of the support bowl supporting the inner tube fitting 12 of the body 16 can advantageously be increased.

In the suspension bush 10 having such a structure, as described above, the suspension rod 18 is inserted into the inner cylinder fitting 12, while the outer cylinder fitting 14 is attached to the mounting fitting provided on the body side. By being fixed, it is attached, and is thereby attached between the suspension unit and the body. Further, in such a mounted state, the inner and outer cylinder fittings 12,
When a vibration in the radial direction in which the fluid chambers 48 oppose each other is input between the fluid chambers 14, a relative internal pressure change occurs between the two fluid chambers 48, 48, and the relative internal pressure changes. Based on the change, a fluid flow through the orifice passage 50 occurs between the two fluid chambers 48,48. As a result, an effective vibration damping effect is exerted on the basis of the flow action such as the resonance action of the fluid flowing through the orifice passage 50.

Further, in the suspension bush 10 of the present embodiment, a concave groove 38 for forming the orifice passage 50 is formed on the outer peripheral portion of the integrally vulcanized molded product 22 by the axial groove portion 38a and the circumferential groove portion 38b. Since it can be formed so as to extend in both the axial direction and the circumferential direction, it is possible to secure a passage length longer than the orifice passage formed simply extending in the circumferential direction. Therefore, it is possible to advantageously increase the length of the orifice passage and the range of selection of the parameters of the cross-sectional area for obtaining the suspension bushing, thereby advantageously increasing the degree of freedom in designing the suspension bush 10.

Further, in the rubber elastic body 16, the pocket 2 provided in the rubber elastic body 16 is provided.
The main body rubber is constituted by the circumferential side wall portions of the two pocket portions 24, 24, since the circumferential side wall portion between the two pocket portions 24, 24 is hollowed radially inward from the end face of the window portion 26. The effective free length of the support bowl for supporting the inner cylinder 12 of the elastic body 16 can be effectively increased, and as a result, when the inner cylinder 12 is twisted around the axis, the main rubber elastic body is used. Suspension bush 1 with excellent torsional durability of 16
0 can be advantageously realized.

As described above, one embodiment of the present invention has been described in detail. However, this is a literal example.
It is to be understood that they are not to be construed as limited to only such illustrative examples.

For example, as described above, the concave groove 38 provided in the orifice disposition portion 36 is not a rectangular wave shape which is formed by combining the axial groove portion 38a and the circumferential groove portion 38b and extends alternately in the circumferential direction and the axial direction. It doesn't matter what, for example,
As shown in FIGS. 9A and 9B, the groove 6 extending in the circumferential direction is used.
It may be configured to include a groove portion 0 and a groove portion 62 extending obliquely in the axial direction, or a groove portion 62 extending only in the oblique direction. In these cases as well, of the two side wall surfaces forming the groove extending in the axial direction, the side wall surface closer to the pocket portion from the center in the circumferential direction of the orifice arrangement portion 36 is the inclined surface 40. It will be.

In the above example, a relatively simple structure of the fluid-filled cylindrical vibration damping device is shown, but the present invention is interpreted as being limited to such a structure. It is not limited to this, and various known structures are appropriately adopted.For example, an internal pressure for controlling the internal pressure of the fluid chamber by vibrating a part of the wall of one fluid chamber or the like. The present invention is, of course, applicable to an active cylindrical vibration isolator provided with a control unit.

Further, providing the metal sleeve 20 on the outer peripheral surface of the main rubber elastic body 16 is extremely effective in securing the mounting strength of the outer cylinder fitting 14 to the main rubber elastic body 16 and ensuring the sealing performance of the sealed fluid. However, such a metal sleeve is not essential in the present invention.

Furthermore, the seal lip 44 provided on the inner peripheral surface of the outer cylinder 14 is also extremely effective in improving the strength of assembling the outer cylinder 14 with the rubber elastic body 16 and the sealing property of the sealed fluid. However, such a seal lip is not essential in the present invention.

In addition, it goes without saying that the present invention can be applied to any of various fluid-filled cylindrical vibration damping devices used for automobiles other than the suspension bush or used for other purposes.

In addition, although not enumerated one by one, the present invention
Based on the knowledge of those skilled in the art, the present invention can be implemented in a form in which various changes, modifications, improvements, and the like are made.
It goes without saying that all such embodiments are included within the scope of the present invention, without departing from the spirit of the present invention.

[0044]

As is apparent from the above description, according to the present invention, when a concave groove is provided in the outer peripheral portion of the main rubber elastic body in a direction perpendicular to the mold opening direction, The problem that it is difficult to remove the mold is solved by absorbing such mold contact by the elastic deformation action of the rubber on the side wall surface that is the inclined surface of the concave groove, It can be removed, so that the width of selection of length and cross-sectional area used for tuning the characteristics of the orifice passage formed by such a groove can be advantageously expanded, and such a mold opening direction Since it is possible to adopt a molding die having the following configuration, it is possible to gouge the circumferential side wall portion of the pocket portion forming the fluid chamber, and increase the effective free length of the support bowl portion of the inner member of the main rubber elastic body. Can do It is the became possible to be brought advantageously improved torsional resistance of the body rubber elastic body.

[Brief description of the drawings]

FIG. 1 is a cross-sectional explanatory view showing a vehicle suspension bush as one embodiment of the present invention, and is a view corresponding to a II section in FIG. 2;

FIG. 2 is an explanatory sectional view taken along the line II-II in FIG.

FIG. 3 is a front view showing an integrally vulcanized molded product including an inner cylinder fitting and a main rubber elastic body, which constitutes the suspension bush shown in FIG. 1;

FIG. 4 is an explanatory sectional view taken along the line IV-IV in FIG. 3;

FIG. 5 is a sectional view taken along line VV in FIG. 4;

FIG. 6 is a longitudinal sectional view showing a state before diameter reduction processing of an outer cylinder fitting constituting the suspension bush shown in FIG. 1;

FIG. 7 is a longitudinal sectional view showing a state in which the integrally vulcanized molded product shown in FIG. 3 is inserted into the outer tube fitting shown in FIG.

FIG. 8 is an explanatory diagram for explaining a manufacturing process of the integrally vulcanized molded product shown in FIG.

FIG. 9 is a partially enlarged view illustrating a shape of a concave groove provided in an orifice arrangement portion as another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Suspension bush 12 Inner cylinder fitting 14 Outer cylinder fitting 16 Main rubber elastic body 18 Suspension rod 20 Metal sleeve 24 Pocket part 26 Window part 28 Stopper 38 Depression groove 38a Axial groove part 38b Circumferential groove part 48 Fluid chamber 50 Orifice passage 52, 54 Mold

Claims (4)

[Claims] 1. An outer member having a cylindrical shape and an inner member which is disposed so as to penetrate through the inside of the outer member and extends in the axial direction thereof, are connected by a rubber elastic body having a cylindrical shape as a whole. On the other hand, a first pocket portion and a second pocket portion which are provided on both sides in the radial direction sandwiching the inner member in the main vibration input direction and are provided so as to open to the outer peripheral surface of the main rubber elastic body. By covering with the outer member, two fluid chambers filled with an incompressible fluid are formed.Furthermore, the first and second outer peripheral portions of the main rubber elastic body located between the two fluid chambers are formed. Forming a groove extending between the openings of the second pocket portion and covering the groove with the outer member to form an orifice passage connecting the fluid chambers to each other; Type cylindrical anti-vibration device. A side wall portion including at least an axial groove extending in the axial direction of the main rubber elastic body, and a side wall portion located on a side closer to one of the two fluid chambers among side walls on both sides providing the axial groove. Wherein the axial groove portion has an opening that expands outward in the radial direction of the main rubber elastic body. Type cylindrical vibration isolator. 2. The method according to claim 1, wherein the concave groove includes a circumferential groove extending in a circumferential direction of the main rubber elastic body together with the axial groove, and the axial groove and the circumferential groove are alternately combined. 2. A groove arrangement structure having a rectangular waveform bent shape in a plane form.
4. A fluid-filled cylindrical vibration isolator according to claim 1. 3. A cross-sectional area of an axial groove formed by inclining one of the side wall portions is equal to a cross-sectional area of a groove other than the axial groove in the concave groove. 3. The fluid-filled cylindrical vibration isolator according to 2. 4. When manufacturing the fluid-filled cylindrical vibration isolator according to claim 1, the inner member and the main rubber elastic body are prepared as an integrally vulcanized molded product. In addition, such an integrally vulcanized molded product has a dividing surface extending in the axial direction at a circumferential central portion of an outer peripheral portion of the main rubber elastic body in which the orifice passage is formed, and is provided on the main rubber elastic body. A fluid-filled cylindrical vibration isolator characterized by being formed by vulcanization using a two-part mold that is opened in the direction in which the first pocket part and the second pocket part face each other. How to make the device.