JPS60179542A - Liquid containing bushing - Google Patents

Abstract

PURPOSE:To obtain a high damping force in a low frequency vibration range while a low transmitting force of vibration is maintained in a high frequency range, by providing such an arrangement that a pair of fluid chambers formed in a bushing are directly communicated together upon high frequency vibration while they are communicated together by way of an orifice upon low frequency vibration. CONSTITUTION:A pair of fluid chambers 26, 26 which are defined by an inner cylindrical metal member 12, an outer cylindrical metal member 14 and a rubber resilient member 16 are communicated together through communication holes 36, 36 in which movable members 38, 38 are disposed, for blocking the communication holes 36, 36 upon low frequency vibration so that the fluid chamber 26, 26 are communicated together through an orifice 42 while the fluid chambers 26, 26 are freely communicated together through the communication holes 36, 36 upon high frequency vibration. The inner cyrindrical metal member 12 is provided with stoppers 30, 30 against which the outer metal cylindrical member 14 abuts and which prevent the rubber resilient member 16 from excessively deforming.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluid-filled bushing that achieves a vibration damping function by using the elastic deformation of a rubber elastic body and the viscous resistance (flow resistance) of an incompressible fluid, and particularly relates to a fluid-filled bushing that achieves a vibration damping function by using elastic deformation of a rubber elastic body and viscous resistance (flow resistance) of an incompressible fluid. The present invention relates to a fluid-filled bushing exhibiting nonlinear characteristics.

Conventionally, various types of arms and ronds have been used to mount differential gears, wheels, etc. to the car body.

Suspension members such as links are provided so as to be swingable in various directions,
Suspension bushings are generally incorporated into the pivot joints at both ends of these suspension members for vibration isolation. Also used are engine mounts that are disposed between the engine and the vehicle body to suppress the transmission of vibrations.

By the way, such a suspension bush.

The anti-vibration support for the engine mount, etc., is provided between an inner cylinder metal fitting and an outer cylinder metal fitting that are arranged concentrically with each other.
It has a structure in which a rubber elastic body is interposed, and the vibration damping function is achieved by the elastic deformation of this rubber elastic body.In recent years, however, by utilizing the viscous resistance of fluid, Composite bushings, in other words, fluid-filled bushings, have been proposed to enhance the damping function.

In such a fluid-filled bushing, a pair of fluid chambers each filled with a predetermined incompressible fluid are formed in the rubber elastic body, and a communication path is provided to allow the fluid chambers to communicate with each other. The structure has a damping effect against vibrations due to the viscous resistance that occurs when the fluid sealed in one fluid chamber flows through the two communication passages (orifice) into the other fluid chamber during vibration input. It was designed to be fulfilled.

However, in conventional fluid-filled bushings that can be bent, it is difficult to determine the constriction plate of the communication passage (orifice), and it is difficult to determine the diameter of the communication passage in order to obtain a high U in the low frequency vibration range. This hinders the isolation of vibrations in the high frequency range (the vibration transmission force increases), and conversely, if the diameter of the communication path is increased to keep the vibration transmission force low in the high frequency range, low frequency vibrations There was a problem that the damping effect for

In addition, when vibration loads that cause large displacements are applied,
Although it is desirable to prevent large relative displacement between the outer cylindrical metal fitting and the cylindrical metal fitting, and thus excessive deformation of the rubber elastic body, this is hardly expected with conventional fluid-filled bushings. However, if the diameter of the communicating path is made as small as possible to increase the viscous resistance given to the fluid, excessive deformation of the rubber elastic body can be suppressed to a certain extent, but especially when a large impact load is applied. However, it is still insufficient;
Moreover, since it is necessary to reduce the transmission force of vibration in the high frequency range, the diameter of the communication passage cannot be made too small, so rubber i
i! It must be said that there is very little hope of preventing excessive deformation of the ij-like body.

The present invention was made against the background of the above-mentioned circumstances, and its purpose is to maintain a high damping force in the low frequency range while keeping the vibration transmission force low in the high frequency range.
To provide a fluid-filled pusher 1 capable of reliably preventing excessive deformation of a rubber elastic body against an impulsive excitation force.

In order to achieve such an object, the present invention includes the above-mentioned inner cylinder metal fitting, outer cylinder metal fitting, gong J, elastic body, and the like.
In a fluid-filled bushing having a structure in which a set of fluid chambers and a communication path for making the fluid chambers communicate with each other,
I11 A stopper means fixed to the cylindrical fitting and having a predetermined height extending from the inner cylindrical fitting to the outer cylindrical fitting is provided in the fluid chamber so that the outer cylindrical fitting can come into contact with the stopper means, and (b) ) a movable member is provided in the communicating path, which is movable between a position where the communicating path is blocked and a position where the communicating path is not blocked, and which is moved to a position where the communicating path is blocked by a pressing force accompanying the flow of the fluid; (C1 Furthermore,
Orifice means is provided for allowing the two fluid chambers to communicate with each other and in a state that provides greater flow resistance than the communication path to the flow of the fluid even when the communication path is blocked by the movable member. It was.

In this way, since the vibration amplitude is small during high frequency vibration, the movable member does not block the communication path 111i, and the fluid sealed in both fluid chambers can freely flow through the communication path. Therefore, the dynamic spring constant is kept low, and the vibration transmission force in the high frequency range can be kept small. On the other hand, since the vibration amplitude is large during low frequency vibration, the movable member is moved to a position where it blocks the communication path by the pressing force of the fluid, and as a result, the flowing fluid passes through the orifice which provides greater flow resistance than the communication path. Since the two fluid chambers cannot be mutually communicated without passing through the orifice means, a high damping force can be obtained due to the resistance generated when the fluid flows through the orifice means.

Moreover, even when a large excitation force of i + j impact is applied at low frequency, the flow resistance that the rewiring means gives to the fluid causes a large relative displacement between the inner and outer cylindrical fittings, and eventually the rubber elasticity. After excessive deformation of the rubber elastic body is suppressed and such a buffering effect is generated, the outer cylindrical metal fitting is brought into contact with the stopper means, whereby excessive deformation of the rubber elastic body can be reliably prevented, This made it possible to improve its durability and avoid problems such as interference between functional parts. In particular, after the orifice means acts as a buffer against such large displacement, the stopper means finally restricts the large displacement, so that excessive displacement can be reliably prevented with a small and smooth fii impact. In other words, the rubber elastic body, the stopper means, and the incompressible fluid.
Due to the mutual effect of the two, it has become possible to provide a composite bushing that has non-electrically smooth nonlinear characteristics and good vibration isolation characteristics in both high and low frequency ranges. It is.

Hereinafter, two embodiments in which the present invention is applied to an automobile suspension bushing will be described in detail with reference to the drawings.

In FIGS. 1 and 2, such a suspension is shown. This bushing 10 has a relatively thick inner cylindrical metal fitting 12 on its innermost side, and an outer cylindrical metal fitting 14 is arranged concentrically at a predetermined distance on the outside thereof.
Moreover, an annular rubber sleeve 16 functioning as a rubber elastic body is concentrically assembled between the inner cylindrical metal fitting 12 and the outer cylindrical metal fitting 14. The inner peripheral surface of the rubber sleeve 16 is vulcanized and bonded to the inner cylindrical metal fitting 12, while a cylindrical metal ring 18 is vulcanized and bonded to its outer peripheral surface. Furthermore, this rubber sleeve 16 has two recesses 20 extending in the circumferential direction at mutually symmetrical positions with the inner cylinder fitting 12 in between.
are formed to open on the outer circumferential surface, and windows 22 are formed in the metal ring 18 corresponding to the openings of these recesses 20, respectively.

On the other hand, the outer cylinder metal fitting 1 located on the outside of this Zento ring 18
4 is integrally provided with a thin rubber layer 24 on its inner peripheral surface, and is brought into close contact with the outer peripheral surface of the metal ring 18 via this rubber layer 24, and the peripheral edges of both f'7j:l are attached to the metal ring 18. As a result, each recess 2
0 openings are fluid-tightly closed to define a pair of mutually symmetrical fluid chambers 26,26. A predetermined incompressible fluid (hereinafter simply referred to as fluid) such as polyalkylene gellicol, silicone oil, or water is sealed in each of the fluid chambers 26 and 26 thus defined.

Further, a metal block body 28 is press-fitted into the center hole in the axially intermediate portion of the inner cylinder fitting 12.
It is integrated with. This pro-two body 28 has a pair of stopper portions 30 that protrude from both sides of the inner tube fitting 12 in the radial direction, and these stopper portions 30 are connected to the inner tube fitting 12.
The projecting portions 32 each extend in a direction perpendicular to each other, and have a cross-sectional shape of a cross. Each stop horn portion 30 is located within the pair of fluid chambers 26, has a predetermined height extending from the outer peripheral surface of the inner cylindrical fitting 12 to the inner wall surface of the outer cylindrical fitting 14, and has a predetermined height. Face is outside ↑6
It is formed into a cylindrical surface shape that substantially corresponds to the inner wall surface of the J metal fitting I4, and a rubber layer 34 is fixed to the surface to form a flat surface. Then, the stopper surfaces of these stopper parts 30 are opposed to the inner wall surface of the outer cylinder fitting 14 at an equal distance apart from each other when the inner cylinder fitting 12 and the outer cylinder fitting 14 are in a concentric state. Metal fittings 12 and 14
This constitutes a stopper means that brings the outer cylindrical metal fitting 14 into contact and stops when a large relative displacement in the radial direction occurs between the two.

On the other hand, each protruding portion 32 of the block body 28 is connected to the stopper portion 3
It extends in both directions perpendicular to the height direction of 0, is surrounded by the comb sleeve 16, and is vulcanized and bonded to it. Communication holes 3 (i, 36) with a rectangular cross section are formed.These communication holes 36 are provided to penetrate each protrusion 32 in a direction parallel to the height direction of the soba part 30, and are arranged to pass through each protrusion 32 in a direction parallel to the height direction of the soba part 30. It serves as a communication path that allows the chambers 26, 26 to communicate with each other.

A rubber movable body 38, 38 functioning as a movable member is disposed in each communication hole 36, respectively. As is clear from FIGS. 3 and 4, this movable body 38 has annular flanges 40.4 at both ends of a quadrangular prism body.
0, and as shown in FIG.
Fil B+< is positioned in the communication hole 36 with a radial gap between it and the four hole wall surfaces, and the flanges /10.40 at both ends sandwich the protrusion 32 from both sides, In addition, it is assembled in such a manner that an axial gap may be generated between the opening peripheral edge of the communication hole 36 and the opening periphery of the communication hole 36 .

Therefore, these movable bodies 38 can move in the direction of the center line of the communication hole 36 within the range of the axial clearance, and when one of the flanges 40 is seated on the peripheral edge of the opening, the movable body 38 can move in the direction of the center line of the communication hole 36. It is designed to be blocked. In other words, it is movable between a position where the communication hole 36 is blocked and a position where it is not blocked.

Note that the opening peripheral portions on both sides of the communication hole 36 are formed by flanges 40.
It is formed into a planar shape so that the inner surface of the gong and sleeve 16 can be seated in close contact with each other, and the communication hole 38 is formed in the metal block body 28, so that regardless of the elastic deformation of the gono and sleeve 16, Its cross-sectional dimensions are always kept constant,
Smooth movement of the movable body 38 is maintained.

Furthermore, as is clear from FIG. 3, these movable bodies 38 have an orifice groove 42 formed in the axial direction from one flange 40 to the other flange 40 via the side surface of the body. This orifice groove 42 functions as an orifice means that connects the two fluid chambers 26 and 26 to each other even when the movable body 38 blocks the communication hole 36. It plays a role of allowing the fluid to flow between the fluid chambers 26.

When the flange 40 of the movable body 38 is not seated on the periphery of the opening of the communication hole 36, the fluids in both fluid chambers 26 flow into each other through the gap between the flange 40 and the periphery of the opening. is allowed, but the viscous resistance imparted to the fluid is relatively small. On the other hand, with the movable body 38 blocking the communication hole 36, the orifice groove 42
The cross-sectional area of the orifice groove 42 is determined so that when the fluid is allowed to flow through the orifice groove 42, the viscous resistance given to the fluid is greater than in the non-blocked state.

Note that the fluid that is allowed to flow through the orifice groove 42 in the blocked state is also allowed to flow through the gap between the wall surface of the communication hole 36 and the wall surface of the movable body 38, so strictly speaking, the fluid that is allowed to flow through the orifice groove 42 The portion formed on the flange 40 essentially functions as an orifice.

By the way, such a suspension bushing 10 is
For example, it can be manufactured through the following steps.

First, the block body 28 is press-fitted into the inner cylindrical metal fitting 12 and integrated. The communication hole 36 is formed before or after the press-fitting, and the rubber layer 34 is vulcanized and bonded in advance)1. Then, the thus integrated member and the metal ring 18 are set concentrically in a predetermined mold, and
A rubber sleeve 16 is vulcanized and molded between them to form a pair of recesses 20. Next, a movable body 38 made of rubber is inserted into each of the communication holes 36 of the vulcanized molded product thus obtained, while being forcibly elastically deformed.

At this time, the orifice groove 42 of the movable body 38 becomes effective in facilitating elastic deformation of the movable body 38. On the other hand, a thin rubber layer 24 is previously vulcanized and bonded to the inner peripheral surface of the outer cylinder fitting 14.

Then, in the liquid tank containing the fluid as described above, the outer cylindrical fitting 14 is fitted to the outside of the vulcanized molded product (butcher assembly) in which the movable bodies 38 are respectively incorporated, and the outer cylindrical The metal fitting 14 is drawn from the outside, and the inner wall surface of the outer cylinder metal fitting 14 and the metal ring 1 are connected via the rubber layer 24.
By liquid-tightly contacting the outer peripheral surfaces of the fluid chambers 8 and 8, each fluid chamber 26 is defined, and at the same time, the fluid is sealed inside the fluid chamber 26. Thereafter, the peripheral edges of both ends of the outer cylinder fitting 14 are caulked, and if necessary, a drawing process is applied to adjust the outer diameter of the product to obtain the suspension bushing 10 as shown in FIGS. 1 and 2. It will be completed.

Such a suspension bushing 10 has an inner cylinder fitting 1.
For example, a pivot shaft on the vehicle body or the accelerator housing side is inserted into the inside of the IY! It is used in a state where it is fitted to the boss part of a hanging arm, rond or link.

When inputting vibration with high frequency and small displacement, the inner t, ↑1
Both fluid chambers 2 due to relative displacement between the metal fitting 12 and the outer cylinder metal fitting 14
Due to the volume change in 6.26, each of the movable bodies 38 is subjected to a fluid pressure action in its axial direction, but since the vibration amplitude is small during high-frequency vibration, each movable body 38 does not block the communication hole 36. Through the gap between the flange 40 and the peripheral edge of the opening of the communication hole 36, the fluid is allowed to flow between the two fluid chambers 26 and 26, so to speak. No large viscous resistance occurs. Therefore, the dynamic spring constant of the bushing 10 is kept low and the soft spring characteristics are maintained, so the vibration isolation characteristics in the high frequency range are high. It can be effectively reduced.

On the other hand, when a vibration is input that causes a large displacement at a low frequency, the volume of the fluid chambers 26 and 26 changes greatly, and the pressing force that each movable body 38 receives from the fluid also increases. The flanges 40 of I::5 are alternately seated on the periphery of the opening of the communication hole 36 to block it. As a result, the fluid in both fluid chambers 26.26 is
They are essentially allowed to communicate with each other only through the orifice groove 42 formed in the movable body 38, and the viscous resistance generated at this time generates an effective damping force against low-frequency vibrations, such as when starting or suddenly stopping. This has the effect of quickly reducing large-amplitude vibrations that occur in the

Moreover, when a large impact load is applied, a large vibration damping force is generated due to the fluid flowing through the orifice grooves 42 in a double series, and the inner wall surface of the outer cylindrical fitting 14 is eventually The rubber sleeve 1 due to such a large load is brought into contact with the strike collar portion 30.
Excessive deformation of the rubber sleeve 16 can be reliably prevented.
can increase the durability of In particular, since the outer cylindrical metal fitting 14 is brought into contact with the stopper portion 30 after the vibration of large displacement has been sufficiently damped, the impact of the contact is small and the stopper action is smooth on the uneven surface. is obtained. Further, a rubber layer 34 is fixed to the stopper surface of the stopper part 30, and the rubber layer 24 of the outer cylinder fitting 14 is brought into contact with this rubber layer 34, so that the cushioning effect is further enhanced. , and there is an advantage that contact between metals can be avoided.

In addition, the movable body 38 is replaced with a rubber one, and as shown in FIGS. 5 and 6, two metal block pieces 44. ．． It is also possible to adopt a metal movable body 38 that is integrated by inserting the movable body 46 from both sides of the communication hole 36 and press-fitting it at the abutting portion. When such a metal movable body 38 is employed, it is desirable to fix a rubber layer to the opening periphery of the communication hole 36 to improve adhesion.

Also, instead of forming the orifice groove 42 on the side of the movable piece 38, whether made of rubber or metal,
° It is also possible to form an orifice hole penetrating in the axial direction in the center thereof and to function it as an orifice means. Further, as shown in FIG. 7, a plate-shaped movable plate 48 is used as a movable member, and this movable plate 48 is accommodated in an annular groove 50 provided in the middle of the communication hole 36, and the movable plate 48 is accommodated in the groove width direction. An embodiment is also adopted in which the movable plate 48 is movable between a position where the communicating hole 36 is blocked and a position where it is not blocked, and an orifice hole 52 is formed in the movable plate 48. The orifice means, such as the orifice hole 52, are not limited to being provided in the movable body 38 or the movable plate 48 itself, but can also be provided in other parts.Specific examples thereof are shown in FIGS. 8 and 9. ing.

In this embodiment, the outer wall surface of the inner cylinder fitting 12 and the block body 2
Bypass passages 54 .
54 are provided for both fluid chambers 26, . 26 are communicated in parallel with the communicating holes 36, 36, and these bypass passages 54, 54 function as orifice means.

That is, as is clear from FIGS. 10 and 11, the movable body 38 has an orifice groove 42 as in the above embodiment.
is not provided and the flange 40 is seated on the opening periphery of the communication hole 36 to block it, the fluid in both fluid chambers 26 flows through the bypass passage 54.
．． By being allowed to mutually circulate through only 54,
Substantially the same as in the previous embodiment, an effective damping force against low frequency, large displacement vibrations is generated. In addition, the 9th
In the figure, each bypass passage 54 is shown as being blocked by the flange 40 of the movable body 38, but there are four bypass passages 54 in total, two on each side of each movable body 38. Both fluid chambers 2 are formed at all times.
6 are in communication.

(In this example as well, a metal movable body 38 as shown in FIGS. 12 and 13 can be used instead of the rubber movable body 38, and other parts Since these are similar to the embodiments shown in FIGS. 1 and 2, corresponding reference numerals are given and explanations thereof will be omitted.

Furthermore, even if the orifice means is provided separately from the movable member such as the movable body 38, as shown in FIG.
It is also possible to make the plate-shaped movable plate 56 function as a movable member, and to provide a bypass passage 58 separately from it to serve as an orifice means.

In addition, the present invention may be modified in various ways based on the knowledge of those skilled in the art, including applying the present invention to other vibration-proof supports such as engine mounts. Needless to say again.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a suspension bushing that is an embodiment of the present invention, and is a sectional view taken along line I-1 in FIG. 2. FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and FIGS. 3 and 4 are a plan view and a front view, respectively, showing the movable body there. 5 and 6 are a plan view and a front view showing another aspect of the movable body, and FIG. 7 is a conceptual cross-sectional view schematically showing the main parts of another embodiment of the present invention. It is a diagram. FIG. 8 is a longitudinal cross-sectional view of a suspension bushing according to another embodiment of the present invention, and is a cross-sectional view taken along the line -■ in FIG. 9. FIG. 9 is a sectional view taken along line IX-IX in FIG. 8, and FIGS. 10 and 11 are a plan view and a front view, respectively, showing the movable body there. Further, FIG. 12 and FIG. 13 are a plan view and a front view, respectively, showing another aspect of such a movable body, and FIG. 14 is a simplified diagram showing the main part of another embodiment of the present invention. It is a conceptual cross-sectional view. 10: Suspension bushing (fluid-filled bushing) 12: Inner cylinder metal fitting 14: Outer cylinder metal fitting 16: Rubber sleeve (rubber elastic body) 26: Fluid chamber 28; Bloso body 30: Stroke part (stopper means) 32: Projecting part 36 : Communication hole (communication path) 38: Movable body (
Movable member) 40: Flange 42 Niorifice groove (orifice means) 4B, Ri 6: Movable plate (movable member) 52 Niorifice hole (orifice means) 54.58: H bus passage (orifice means) Applicant Tokai Rubber Industries Co., Ltd.

Claims (3)

[Claims] (1) A pair of rubber elastic bodies are interposed between an inner cylindrical metal fitting and an outer cylindrical metal fitting that are arranged concentrically with each other, and a predetermined incompressible fluid is sealed in each of the rubber elastic bodies. In a fluid-filled bushing having a structure in which a fluid chamber is formed and a communication path is provided for communicating between the fluid chambers, the bushing is fixed to the inner cylindrical metal fitting within the fluid chamber, and is connected from the cylindrical metal fitting to the outer cylindrical metal fitting. A stopper means extending to a predetermined height is provided so that the outer cylindrical fitting can come into contact with the stopper means, and the stopper means is movable in the communication path between a position where the communication path is blocked and a position where the communication path is not blocked. A movable member is provided that can be moved to a position where the communication path is blocked by a pressing force accompanying the flow of the fluid, and further, even when the communication path is blocked by the movable member, both of the fluid chambers are A fluid-filled bushing, characterized in that it is provided with orifice means for allowing the fluid to communicate with each other in a state that provides greater flow resistance than the communication path to the flow of the fluid. (2) The fluid-filled bushing according to claim 1, wherein the orifice means is provided on the movable member. (3) The fluid-filled bushing according to claim 1, wherein the orifice means is constituted by a bypass passage formed in parallel with the communication passage.