JPS6110138A - Bush encapsulated with fluid - Google Patents

Abstract

PURPOSE:To improve the durability of resilient member by providing a stopper section of specific height at the pocket section for encapsulating non-compressive fluid thereby preventing deformation of resilient member more than predetermined amount. CONSTITUTION:Plural pocket sections 30 for encapsulating non-compressive fluid are provided in a resilient member 8 inserted between an inner tube metal 4 and an outer tube metal 16. A stopper member 6 having a stopper section 24 of specific height projecting into said pocket section is inserted and secured to the inner tube metal 4 while an orifice 26 communicatable between the pocket sections 30 is formed at the boss section 22 of the stopper member 6. Upon contact of the stopper section 24 against the outer tube metal 16, further deformation of the resilient member 8 is prevented resulting in improvement of the durability of the resilient member 8.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an improved structure for a fluid-filled bushing;
In particular, the present invention relates to a highly durable fluid-filled bushing that effectively utilizes hydraulic damping force due to the inclusion of an incompressible fluid in addition to the vibration-damping effect of an elastic member.

Prior Art Conventionally, various arms and ronds have been used to suspend differential gears, wheels, etc. to the body of automobiles and the like.

Suspension members such as links are attached so as to be able to swing in various directions, and suspension bushings are generally incorporated into the pivot joints at both ends of the suspension members for the purpose of damping vibrations. An engine mount, which is inserted between the engine and the vehicle body to suppress the transmission of vibrations, is also used as a mount for the same purpose.

By the way, a bushing as a vibration-proof support such as a suspension bushing or an engine mount generally consists of an inner metal fitting into which a predetermined pivot is inserted for vehicle suspension, and an outer cylinder arranged concentrically with the internal metal fitting. It has a structure in which an annular rubber sleeve is inserted between the metal fitting and vibrations are damped by deformation of the rubber sleeve, but in recent years, such rubber sleeves have been formed. A composite bushing 3, in other words, a fluid-filled bushing, has been proposed which generates a desirable damping function as a buffering function of the bushing without using a rubber material having a particularly high damping coefficient.

Namely, Japanese Patent Publication No. 48-36151, Japanese Patent Publication No. 52
As disclosed in Japanese Patent Laid-open No. 16554 and Japanese Patent Application Laid-Open No. 164242/1983, such a composite bushing has a plurality of recesses on the surface of a rubber sleeve inserted between an inner cylindrical metal fitting and an outer cylindrical metal fitting. A pocket formed between the recess and the inner wall of the outer cylindrical fitting is filled with a predetermined fluid, and the pockets are communicated through an orifice. The resistance generated when the fluid filled in one pocket flows through the orifice into the other pocket provides a good damping effect.

Problems to be Solved However, in such conventional composite bush structures, desirable hydraulic damping force can be expected due to the resistance (viscous resistance) caused when fluid passes through the orifice as described above. , no consideration was given to preventing excessive deformation of the bushing, or in other words, excessive deformation of the rubber sleeve inserted between the inner metal fitting and the outer cylindrical metal fitting. Depending on the magnitude of the load applied through the rubber sleeve, the rubber sleeve deforms, and especially when a large load is applied, the rubber sleeve undergoes large deformation (large strain),
By repeatedly undergoing such large deformations, the rubber sleeve is damaged and its durability becomes inferior. In addition, when a large load is applied to such a composite bush, the rubber sleeve portion located on the opposite side in the circumferential direction to the area where the large load is applied can follow the large deformation caused by such a large load. As a result, the sealing function between the inner wall surface of the outer cylinder metal fitting and the inner wall surface of the outer cylinder metal fitting is deteriorated, which may cause a problem in which the fluid contained in the pocket portion leaks to the outside.

The present invention has been made against this background, and its main purpose is to improve a fluid-filled bushing that utilizes a fluid medium and has high damping characteristics. It is in.

Another object of the present invention is to provide a fluid-filled bushing for a vehicle that does not deform excessively under heavy loads, has significantly increased durability, and has improved sealing effectiveness. .

Solution: In order to achieve these objects, the present invention includes an annular elastic member interposed between an inner cylindrical metal fitting and an outer cylindrical metal fitting that are arranged concentrically, and the elastic member a plurality of insulators communicated with each other via orifices;
Separate recesses are provided to define a plurality of pockets between the outer cylinder metal fitting or the outer cylinder metal fitting and the inner cylinder metal fitting, and a predetermined incompressible fluid is sealed in the plurality of pocket parts. In the bushing, the desired damping effect is exerted by the resistance generated when the incompressible fluid flows from one pocket to the other through the orifice. A ring-shaped stopper member having a protruding stopper portion of a predetermined height is provided, and the outer cylindrical metal fitting is brought into contact with the stopper member when a large load is applied, thereby regulating deformation of the elastic member, and The orifice is formed in the stopper member so as to pass through the boss portion thereof.

Functions and Effects Thus, according to the present invention, there is a stopper portion of a predetermined height extending from the inner cylindrical metal fitting toward the outer cylindrical metal fitting in each recess (pocket portion) of the bushing. Therefore, when a predetermined amount of load is applied to the outer cylindrical metal fitting and a predetermined amount of deformation is induced in the elastic member, the outer cylindrical metal fitting comes into contact with the stopper portion, which causes further deformation of the elastic member. In other words, even if a large load is applied, the elastic member will not be deformed by more than a predetermined amount due to the restriction by the stopper part of the stopper member. Damage caused by large deformation of the elastic member can be effectively suppressed, thereby significantly increasing its durability.

Moreover, since the amount of deformation of the elastic member is regulated by the stopper portion of the stopper member, the sealing effect between the elastic member and the outer cylindrical fitting on the side opposite to the side receiving the load is also effective. As a result, the problem of fluid leakage from the pocket portion has virtually disappeared.

Particularly, in the present invention, an orifice is provided on the inner cylindrical metal fitting side that communicates between a plurality of pocket portions by using a stopper member that is attached to the inner cylindrical metal fitting and whose stopper portion is disposed within the pocket portion. can be effectively formed, thereby enjoying various excellent advantages.

That is, the respective recesses (pocket portions) are communicated through their bottoms by a through hole provided in the stopper member or a groove carved in the inner circumferential surface of the stopper member, and are formed in this way. Since all of the communicating passages are provided in the rigid member, there is no risk that the communicating passages will be deformed by external forces applied to the bushing, and therefore the communicating passages can always maintain a constant shape, and the bushing This has the advantage that the required damping performance is always stabilized, and even if there are air bubbles that enter the recess during the manufacturing process or due to liquid leakage, such air bubbles will Problems such as the orifice function suddenly changing and the vibration damping function becoming unstable are also substantially eliminated.

Moreover, by providing the orifice in the stopper member in this manner, the orifice can be arranged linearly between the pocket parts connected by the orifice, thereby increasing the damping coefficient. In addition, since an orifice is not formed by cutting a circumferential groove on the outer surface of the inner cylindrical fitting, it is possible to prevent the buckling strength (in the axial direction) of the inner cylindrical fitting from decreasing. Of course, since it is not necessary to provide the opening of the orifice on the top surface of the stopper part of the stopper member, the contact area of the stopper part can be increased, which improves its durability even under heavy loads. It is possible to secure it.

EXAMPLES Below, in order to clarify the present invention more specifically, examples of the present invention will be described in detail based on the drawings.

First, FIGS. 1 to 8 show an example of a suspension bush of a suspension arm to which the present invention is applied, and FIGS. 1 and 2 show such a suspension bush. 3 and 4 show an example of a single bushing constituting such a bushing, and Figs. 5 to 7 show an example of a single bushing constituting such a bushing. An example in which the stopper member is attached to an inner cylindrical metal fitting is shown in FIG. 8, and an outer cylindrical metal fitting into which a single bushing is inserted is shown.

In those figures, especially in figures 1 and 2,
Reference numeral 2 designates a suspension bushing which is an embodiment of the present invention, and has a relatively thick cylinder into which a pivot shaft supported by a pair of brackets fixed to the vehicle body, axle housing, etc. is fitted into the innermost part of the bushing. A metal fitting 4 is arranged. A ring-shaped metal stopper member 6 having a symmetrical convex portion is press-fitted into the center of the inner cylindrical fitting 4, and a rubber sleeve (
Elastic member) 8 and metal sleeve with window (rigid member)]
The suspension bushing 2 is constituted by a single bushing 12 in which the numbers 0 are arranged concentrically and adjacent to each other, and an outer cylindrical metal fitting 16 having a rubber layer 14 of a predetermined thickness on the inner surface. There is.

More specifically, as shown in FIGS. 3 and 4, the rubber sleeve 8 has an annular shape as a whole, and has a notched shape at a corresponding position on its outer circumferential surface.
A relatively thin metal sleeve 10 having two circumferentially extending symmetrical recesses 18 and a window 20 corresponding to the opening of the recess 18 is fixed to the outer peripheral surface of the rubber sleeve 8. has been done.

Further, the stopper member 6, which is inserted externally into the inner cylinder fitting 4 and press-fitted and fixed to the outer circumferential surface thereof, has a boss portion 2 having a rectangular cross-section having a circular hole, as shown in FIGS. 5 to 7.
2 and a thick stopper portion 24, 24 protruding outward from the corresponding side of the rectangular cross-sectional shape, respectively. While the inner cylindrical fitting 4 is press-fitted and fixed therein, the stopper portion 24 of the stopper member 6 is
It is located within the recess 18 of the rubber sleeve 8 and extends toward the outer cylindrical fitting 16, forming a protrusion having a predetermined height within the recess 18.

Further, the boss portion 22 of the stopper member 6 has two stopper portions 24, 24 extending linearly on both sides of the stopper portion 24,
Orifices 2'6 and 26, which are straight through holes, are provided at the bases of the stopper portions 24 (see FIG. 6). This orifice 26 allows two corresponding recesses 18.degree. 18 provided in the rubber block 8 to communicate with each other. As shown in FIG. 1.2.4, the arcuate outer circumferential surface of the stopper portion 24 of the stopper member 6, that is, the surface facing the inner surface of the outer cylindrical fitting 16, has, as shown in FIG. A rubber layer 28 of a predetermined thickness is formed, and a continuous space is created around the stopper portion 24 of the stopper member 6 positioned within the two recesses 18, 18. ing.

On the other hand, as shown in FIG. 8, a rubber layer 14 of a predetermined thickness made of rubber as an elastic material is provided on almost the entire inner surface of the outer cylindrical metal fitting 16 into which such a single bushing 12 is inserted. It is formed over.

Then, the outer cylindrical fitting 16 having the rubber ff114 on the inner surface as shown in FIG.
The single bushing 12 in the state shown in the figure is inserted into the inner wall of the outer cylindrical fitting 16 into which it is inserted, the recess 18 of the rubber sleeve 8, and optionally the outer peripheral surface of the inner cylindrical fitting 4. , each having a separate pocket portion 30,30 defined therein, as shown in FIGS. 1 and 2;
A predetermined incompressible fluid 32 is sealed in each of the pockets 30 thus formed. Further, the rubber N14 on the inner surface of the outer cylinder fitting 16 is located between the metal sleeve 10 and the outer cylinder fitting 16, which are fixed by vulcanization adhesive or the like so as to cover the outer circumferential surface of the rubber sleeve 8. The pocket portion 30 is made liquid-tight, thereby preventing the predetermined fluid 32 sealed in the pocket portion 30 from leaking.

By the way, such a suspension bushing 2 is manufactured, for example, according to the following process.

First, when manufacturing a single piece 12 as shown in FIGS. 3 and 4, the inner cylindrical metal fitting 4 is press-fitted and fixed into the circular hole of a predetermined stop and collar member 6. Metal sleeve 10 with a window 20 opened at a predetermined position
are set concentrically in a predetermined mold, a rubber material is injected into the gap between them, and vulcanization is performed to bond the inner cylindrical fitting 4 and sleeve 10, and the rubber sleeve 8 is are vulcanized and molded at the same time. At this time, the rubber material is prevented from entering into the orifice 26 of the stopper member 6, and a recess 18 is formed around the stopper portion 24 of the stopper member 6.
The structure is such that a plurality of the rubber sleeves 8 are opened on the outer circumferential surface of the rubber sleeve 8.

Then, the single bushing 12 formed in this way is radially inwardly drawn through the metal sleeve 10 located on the outer circumferential surface of the bushing 12 by a normal drawing operation using a die or a helical drawing operation. The rubber sleeve 8 is compressed and deformed, and the rubber sleeve 8 is compressed to a predetermined outer diameter. .

On the other hand, a rubber layer 14 of a predetermined thickness is integrally formed on substantially the entire inner surface of the outer cylinder fitting 16 by a similar vulcanization molding operation.

Next, the single bushing 1 is placed in a liquid tank containing an incompressible fluid 32 such as water, alkylene glycol, polyalkylene gellicol, silicone oil, or a low molecular weight polymer.
2 into the outer cylinder fitting 16. By this insertion operation, the recess 18 in the bushing unit 12 and the outer cylinder fitting 1 are connected to each other.
In the pocket portion 30 formed by the inner peripheral surface of 6,
Such fluid 32 can be easily and effectively enclosed.

Then, the insert obtained in this way is held as it is in the fluid 32, or it is taken out from the liquid tank and placed in the atmosphere, and the outer cylindrical fitting 16 is subjected to a squeezing operation to form a sleeve. By applying compression to the rubber layer 14 interposed between 10 and the outer cylinder fitting 16, the seal between them is perfected, and thus the incompressible fluid 32 is contained in each pocket 30. is completely filled, and the desired suspension bushing 2 as shown in FIGS. 1 and 2 is completed.

Therefore, in the suspension bushing 2 having such a structure, there are stopper portions 2 of a predetermined height formed by the protruding portions of the stopper member 6 in the two recesses 18, 18, respectively.
Therefore, even if the outer cylindrical fitting 16 receives a large load, the rubber sleeve 8 will not undergo any larger deformation after it has undergone a predetermined deformation. If the rubber sleeve 8 begins to deform significantly, the stopper portion 24 of the stopper member 6 will disengage from the outer cylindrical fitting 16.
This is because it comes into contact with and prevents further deformation. Therefore, since the rubber sleeve 8 is not subject to large deformation, its durability is further improved. In addition, since no large deformation occurs even when receiving a large load, the portion of the rubber sleeve 8 located on the opposite side to the side receiving such a large load also does not undergo large deformation.
The seal between the outer cylinder fitting 16 and the outer cylinder fitting 16 can also be maintained well, and leakage of the fluid 32 from the pocket portion 30 can also be effectively prevented.

In addition, in the bushing 2 having the structure of the above example, there is an orifice (communication path) that allows the two pocket portions 30 and 30 to communicate with each other.
is formed as a through hole passing through the boss portion 22 of the stopper member 6, so its shape is always kept constant, in other words, the cross-sectional area of the fluid passage is maintained unchanged. As a result, the flow resistance against the external force applied to the bushing 2 becomes constant, and therefore the damping performance against excitation vibrations is also stabilized, and the desired damping function can be permanently obtained. Since such an orifice 26 is provided in the stopper member itself, the stopper member 6 can be used as a member that performs the orifice function as well as its original stop and stop functions. As a result, its structure can be significantly simplified.

Moreover, the orifice 26 provided in the stopper member 6 has a straight shape, and has two pocket portions 30.
30 are linearly connected, it is possible to effectively increase the attenuation coefficient due to the flow resistance of the incompressible fluid 32 passing through it, and the cylindrical metal fitting 4 has a groove for forming an orifice. Since the cylindrical fitting 4 is not provided with a Since it is not provided on the contact surface (upper surface) with the outer cylindrical fitting 16, the contact area of the stopper portion 24 can be made thicker, so that it can withstand large loads.
This allows good durability to be ensured.

Further, according to the structure of the above example, since a predetermined rubber layer 28 is formed on the contact surface of the stopper member 6 with respect to the outer cylinder metal fitting 16, the stopper member 6 that is bent is attached to the outer cylinder metal fitting 16.
6, the rubber layer 14 is further formed on the inner surface of the outer cylindrical fitting 16, so that when repeatedly subjected to heavy loads, the rubber of the 7 bar part This has the effect of reducing damage to (28) and maintaining the stopper effect for a long period of time.In addition, the rubber layer 14 on the outer cylindrical fitting 16 side also serves to prevent rust on the inner surface of the outer cylindrical fitting 16. It is. In addition, the continuous space formed around the stopper part 24 is such that the pocket part 30 is divided into two by the contact between the outer cylinder metal fitting 16 and the stopper part 24.
This prevents the pocket portion 30 from being sealed, thereby suppressing a rise in pressure within the pocket portion 30.

Furthermore, in the suspension bushing 2 having the above-described structure, the orifice 26 that connects the two recesses 18 is provided on the inner cylindrical metal fitting 4 side and each is opened, so that the orifice 26 is deeply immersed in the fluid 32. Therefore, even if gas enters into the pocket part 30 during the production of the bushing, or if gas intrudes due to fluid leaking while the bushing is in use, or if gas is generated, the Since such gas accumulates on the outer periphery of the recess 18, that is, on the outer cylindrical fitting 16 side, the orifice 26 corresponding to the diagonal of the fan
There is almost no possibility that air bubbles will flow into the tank. Therefore, the problem of the conventional bush structure in which air bubbles flow into the communication path of the pocket portion together with the fluid, causing a sudden change in the orifice function and making the damping characteristic extremely unstable, can be satisfactorily solved. In addition, the pocket part 3 located below
Even if a bubble enters the orifice 2, such a bubble will
6 and collect in the upper pocket portion 30, such air bubbles entering the lower pocket portion 30 do not pose a problem.

In addition, by adopting the structure as in the above example, the rubber sleeve 8
This has the advantage that pre-compression can be effectively applied to the rubber sleeve 8, thereby effectively improving the durability of the rubber sleeve 8. Also, there is no rubber layer between the outer cylinder fitting 16 and the metal sleeve 10. 14, the fluid 32 filled in the pocket portion 30 is effectively prevented from returning through the gap between them, and the operation of filling the fluid 32 into the blurred portion 30 is extremely simple. Moreover, it can be easily carried out, and various advantages and effects can be enjoyed, such as significantly improved workability in assembling or assembling the bushings, and ease of mass production.

In the above embodiment, a metal sleeve 10 is provided on the outer circumferential surface of the rubber sleeve 8 to effectively reduce the outer diameter thereof and to prevent fitting into the outer cylindrical fitting 16. However, the present invention is not limited to this in any way, and a bush structure without the outer sleeve 10 can also be adopted.

Furthermore, various modified forms may be adopted for the shape of the stopper member and the orifice provided therein, as long as they do not deviate from the spirit of the present invention. and shown in FIG. That is, in FIG. 9, the orifice 26 is provided so as to pass through the boss portion 22 in a state where the outer surface of the inner cylinder fitting 4 is partially scraped, and in FIG. is a cylindrical body having a rounded and substantially rectangular cross-sectional shape, and penetrates in the radial direction through the circumferential groove 34 formed on the inner surface of the hole of such a stopper member 6 and the stopper portion 24 connected thereto. The hole 36 forms an orifice. Even these orifice structures can be employed as long as they are substantially formed in the stopper member 6.

Furthermore, in the specific example illustrated, a rubber layer 14 is provided on the inner surface of the outer cylinder fitting 16 to improve the sealing performance between the sleeve 10 as the outer rigid part, Even without such a rubber layer 14, the objects of the present invention can be achieved, and other suitable sealing means can be used in place of the rubber Fit 14.

In addition, various changes and modifications can be made to the present invention based on the knowledge of those skilled in the art without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a suspension bushing according to an embodiment of the present invention, and FIG.
■It is a sectional view. 3 is a side view of a single bushing constituting the suspension bushing of FIG. 1, FIG. 4 is a sectional view of such a single bushing corresponding to FIG. 2, and FIG. 5 is a stopper member FIG. 6 is a longitudinal cross-sectional view of an assembled body formed by press-fitting and fixing an inner cylinder metallic mold, FIG. 6 is a cross-sectional view taken along the line Vl--Vl in FIG. 5, and FIG. 7 is a cross-sectional view taken along FIG. 8 is a longitudinal cross-sectional view of the outer cylindrical metal fitting. 9 and 10 are sectional views corresponding to FIG. 1 showing other embodiments of the present invention. 2: Suspension bushing 4: Inner cylinder metal fitting 6: Suspension bushing member 8: Rubber sleeve 10: Metal sleeve 12: Bushing alone Work 4:
Rubber layer 16: Outer cylinder metal fitting 18: Recess 20: Window 22: Boss 24: Stroke portion 26: Orifice 28: Rubber layer
30: Blurred part 32: Incompressible fluid 34: Full 36: Hole

Claims (8)

[Claims] (1) An annular elastic member is interposed between an inner cylindrical metal fitting and an outer cylindrical metal fitting that are arranged concentrically, and the elastic member is made to communicate with each other via a plurality of orifices;
A separate recess is provided to define a plurality of pocket portions between the outer cylindrical metal fitting or the outer cylindrical metal fitting and the inner cylindrical metal fitting, and a predetermined incompressible fluid is sealed in the plurality of pocket portions. In the bushing, the desired damping effect is exerted by the resistance generated when the incompressible fluid flows from one pocket part to the other pocket part through the orifice. A ring-shaped stopper member having a protruding stopper portion of a predetermined height is provided, and the outer cylindrical metal fitting is brought into contact with the stopper member when a large load is applied, thereby regulating deformation of the elastic member, and A fluid-filled bush characterized in that the orifice is formed in the stopper member so as to pass through the boss portion thereof. (2) The stopper member is formed of a cylindrical member made of a rigid material, each having a thick wall portion at a portion where the plurality of pocket portions are formed, and the inner cylindrical metal fitting is disposed within the hollow hole of the cylindrical member. The bush according to claim 1, which is fixed to the inner cylinder fitting by being press-fitted. (3) The bushing according to claim 1 or 2, wherein the orifice is formed by a linear through hole passing through the boss portion of the stopper member. (4) A cylindrical outer rigid member is disposed on the outer circumferential surface of the elastic member so as not to cover the opening of each recess opened on the outer circumferential surface of the elastic member, and the outer cylindrical metal fitting is provided through the outer circumferential rigid member. The bush according to any one of claims 1 to 3, which is fitted into the bush. (5) The bushing according to claim 4, wherein the outer cylindrical metal fitting is caulked to the outer rigid member at both ends in the axial direction. (6) The stopper member has an elastic layer of a predetermined thickness made of an elastic material on a surface facing the outer cylindrical metal fitting, and is brought into contact with the outer cylindrical metal fitting through the elastic layer. A bush according to any one of claims 1 to 5. (7) The outer cylindrical metal fitting has an elastic layer of a predetermined thickness made of an elastic material on its inner surface, and is brought into close contact with the outer circumferential surface of the outer rigid member via the elastic layer. The bush according to any one of items 4 to 6. (8) the stopper member protrudes into the pocket portion;
The bush according to any one of claims 1 to 7, wherein a continuous space is formed around the bush.