JPH0369014B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a vibration isolating bush mainly for isolating vibration input in the radial direction of the bush, and particularly to a vibration damping bush for changing the spring characteristics in the direction of vibration input in the bush radial direction. The present invention relates to a fluid-filled vibration-proof bushing that can be used.

(Prior art and its problems) In a vibration isolating bush mainly for isolating input vibration in the bush radial direction, in the vibration input direction of the bush radial direction, depending on various conditions such as the cause of vibration, Some are required to exhibit different spring characteristics. For example, in the suspension bushing of an automobile suspension, in order to achieve both steering stability and ride comfort of the vehicle,
In the direction of vibration input in the radial direction of the bush, it is required to exhibit soft spring characteristics and hard spring characteristics depending on the operating state and traveling state of the vehicle.

By the way, as a vibration-proof bushing that satisfies such requirements, conventionally, it has a pair of fluid chambers located at a portion of the rubber elastic body facing each other across the inner cylinder member in the vibration input direction, and a A through hole is provided at each position of the facing outer cylindrical member,
A fluid-filled anti-vibration bushing is known in which a predetermined incompressible fluid is allowed to flow in and out of each corresponding fluid chamber through the through holes.
According to the fluid-filled anti-vibration bushing having such a structure, incompressible fluid is caused to flow in and out of each fluid chamber through each corresponding through hole, and by adjusting the fluid pressure in these fluid chambers, the bushing is moved in the radial direction. The spring characteristics in the vibration input direction can be made harder or softer as necessary.

However, in a conventional fluid-filled vibration-isolating bushing having such a structure, although it is possible to vary the spring characteristics in the vibration input direction in the radial direction of the bushing, as described above,
Since piping must be installed for the inflow and outflow of the incompressible fluid, the piping is complicated and troublesome, and moreover, the piping requires a large space.

On the other hand, in a fluid-filled anti-vibration bushing equipped with a fluid chamber and a through hole as described above, the through hole corresponding to both fluid chambers is connected with a predetermined piping, and an electromagnetic A structure has been considered in which a valve mechanism is provided and the two fluid chambers are communicated with each other and shut off by opening and closing operations of the electromagnetic valve mechanism. In this type of device, stiff spring characteristics can be obtained in the opposite direction of the fluid chambers by blocking the two fluid chambers using a solenoid valve mechanism, and conversely, by making both fluid chambers communicate with each other, , the spring characteristics can be softened in the opposite direction of the fluid chamber.

However, in a vibration-proof bushing having such a structure, it is necessary to provide an expensive solenoid valve mechanism on the piping that connects the fluid chambers facing each other in the direction of vibration input, so the vibration-proof bushing inevitably becomes expensive. It has inherent defects that have put it at an economic disadvantage.

(Solution Means) Against this background, the present invention provides a fluid-filled anti-vibration bushing having a function of varying spring characteristics in the direction of vibration input in the radial direction of the bushing, which is different from the conventional fluid-filled anti-vibration bushing. This was done to provide an economically advantageous product that can simplify the external piping compared to anti-vibration bushings. (b) an outer cylinder member disposed at a predetermined distance on the outside of the inner cylinder member; and (c) an elastic member interposed between the inner cylinder member and the outer cylinder member. (d) a cylindrical flexible membrane interposed between the rubber elastic body and the outer cylinder member; (e) the rubber elastic body, At least a pair of pocket portions are formed such that they are open on the outer circumferential surface of the rubber elastic body and are opposed to each other with the inner cylinder member interposed therebetween, and the opening portions are closed with the flexible membrane. and (f) a circumferential groove formed on the outer peripheral surface of the rubber elastic body, the opening of which is closed by the flexible membrane. (g) a through hole formed in a portion of the outer cylinder member corresponding to either the throttle passage or the fluid chamber; h) Allowing a predetermined working fluid to flow in and out through a port inserted into the outer cylindrical member and opened to the outer peripheral surface between the outer cylindrical member and the flexible membrane through the through hole. and a cylindrical port member configured such that the throttle passage can be opened and closed, respectively, by deforming the flexible membrane based on the inflow and outflow of the working fluid through the port of the port member. It's what I did.

(Function/Effect) In such a fluid-filled anti-vibration bushing, when the working fluid is allowed to flow between the outer cylinder member and the flexible membrane through the port of the port member, the flexible membrane will move against the rubber elastic body. It is pressed against the outer peripheral surface and the throttle passage is closed. Therefore, in this state, the fluid chambers are cut off, the volume of each fluid chamber is prevented from changing, and the spring characteristics of the fluid chambers in the opposing direction become stiff.

On the other hand, when the working fluid is allowed to flow out from the space between the outer cylinder member and the flexible membrane through the port of the port member, the flexible membrane is attracted to the outer cylinder member side, and the throttle passage is opened. Therefore, in this case, the volume of the fluid chamber is allowed to change due to the flow of the incompressible fluid through the throttle passage, so that the spring characteristics of the fluid chamber in the opposite direction become soft.

That is, in the fluid-filled anti-vibration bushing according to the present invention, the spring characteristics in the opposite direction of the fluid chamber are changed by allowing the working fluid to flow in and out between the outer cylinder member and the flexible membrane through the port of the port member. Therefore, if the anti-vibration bushing is used with the direction in which the fluid chambers face each other as the vibration input direction, the spring characteristics can be changed as necessary in the vibration input direction.

In the fluid-filled vibration-isolating bushing according to the present invention, the spring characteristics in the vibration input direction can be varied simply by flowing the working fluid into and out of the port of the port member. Only one is required, and therefore, the piping for the anti-vibration bushing can be much simpler than in the past, and the space required for the piping can be significantly reduced. Furthermore, since such a function of varying the spring characteristics can be obtained without using an expensive electromagnetic valve mechanism, it is possible to economically advantageously manufacture a vibration-proof bushing having such a function of varying the spring characteristics. It also became a thing.

(Example) In order to clarify the present invention more specifically, an example in which the present invention is applied to a suspension bush for an automobile suspension will be described below in detail based on the drawings. . In addition,
Here, an example of a suspension bushing will be described in which the spring characteristics can be changed both in two mutually orthogonal directions in the bushing radial direction, that is, in the vertical direction of the vehicle and in the horizontal direction of the vehicle.

That is, FIGS. 1 to 3 show an example of a suspension bush for an automobile suspension according to the present invention. In those figures,
Reference numeral 10 denotes a cylindrical inner metal fitting as an inner cylinder member, and a cylindrical outer metal fitting 1 as an outer cylinder member is placed on the outside of the inner cylinder metal fitting 10 at a predetermined distance.
2 is placed. A thick cylindrical rubber elastic body 1 is provided between the inner cylindrical metal fitting 10 and the outer cylindrical metal fitting 12.
4, and a thin rubber sleeve 16 as a flexible membrane is interposed between the rubber elastic body 14 and the outer cylinder metal fitting 12. In addition, the outer cylinder fitting 1
A thick-walled cylindrical port member 18 is fluid-tightly fitted onto the outer peripheral surface of 2.

The rubber elastic body 14 is integrally vulcanized and bonded to the outer circumferential surface of the inner cylinder fitting 10, and a seal sleeve 22 having an outward flange portion 20 at one end in the axial direction is integrally vulcanized and bonded to the outer circumferential surface. has been done.
The rubber sleeve 16 is disposed between the seal sleeve 22 and the outer cylindrical fitting 12 in a fluid-tight manner.

The outer cylindrical fitting 12 is attached to the seal sleeve 2 at a caulking portion 23 formed at one end in the axial direction.
It is swaged to the outward flange portion 20 of No. 2, and the other end is roll swaged radially inward for assembly.

A pair of cutout windows 24, 24 and 26, 26 are formed in the seal sleeve 22 so as to face each other with the inner cylindrical fitting 10 interposed in two directions perpendicular to each other in the bush radial direction.
The rubber elastic body 14 has cutout windows 24, 24,
Pocket portions 28, 28 and 30, 30 of a predetermined depth are formed with openings at 26, 26, respectively. Here, each cutout window 24, 24, 26, 26 of the seal sleeve 22, which is the opening of the pocket portions 28, 28, 30, 30, is shown.
are fluid-tightly closed by the rubber sleeve 22, so that each pair of fluid chambers 32, 32 and 34, 34 are arranged so as to face each other with the inner cylindrical fitting 10 interposed therebetween in directions orthogonal to each other in the radial direction of the bush.
are formed, and these fluid chambers 32, 32, 3
A predetermined incompressible fluid such as water, polyalkylene glycol, etc. is sealed within the chambers 4 and 34.

In addition, in the pair of fluid chambers 32, 32 facing each other with the inner cylinder fitting 10 interposed therebetween, there are provided a pair of fluid chambers 32, 32, which protrude from the inner peripheral wall by a predetermined height, respectively.
Rubber stoppers 36, 36 are extended to prevent excessive displacement of both metal fittings 10, 12 in opposing directions.

Further, the seal sleeve 22 is connected to the cutout window 2.
The intermediate portion in the axial direction corresponding to the forming portions of the holes 4, 24, 26, and 26 is a small diameter portion 38 over a predetermined length, thereby communicating the circumferentially adjacent cutout windows 24 and 26, respectively. In this state, a wide circumferential groove 40 with a shallow bottom is formed that opens on the outer circumferential surface of the seal sleeve 22. Here, the openings of these circumferential grooves 40 are fluid-tightly closed by the rubber sleeve 22, thereby forming a throttle passage 42 that allows the adjacent fluid chambers 32, 34 to communicate with each other. .

By the way, as shown in FIG. 2, the outer cylindrical fitting 12 has a through hole 44 located at a portion corresponding to the circumferentially intermediate portion of each throttle passage 42 and penetrating inside and outside. For the space between the outer cylinder fitting 12 and the rubber sleeve 16,
Through these through holes 44, the fluid chambers 32, 34
A working fluid similar to the incompressible fluid within is allowed to flow in and out. When the working fluid is allowed to flow into the space between the outer cylinder fitting 12 and the rubber sleeve 16 through the through holes 44, the portion of the rubber sleeve 16 facing each throttle passage 42 expands inward in the bush radial direction. When the working fluid is allowed to flow out from the space between the outer cylinder fitting 12 and the rubber sleeve 16 through the through holes 44, the above-mentioned A portion of the rubber sleeve 16 is attracted to the outer cylinder metal fitting 12 side, and each throttle passage 42 is opened.

On the other hand, the port member 18 fitted to the outer circumferential surface of the outer cylinder fitting 12 has a circumferential annular groove 46 located at a portion corresponding to the formation portion of the through hole 44 and opening to the inner circumferential surface. are formed, and the through holes 44 are communicated with each other through the space within the annular groove 46. A port 48 is formed in the outer circumferential surface of the port member 18 and communicates with the space within the annular groove 46. By allowing working fluid to flow in and out of the port 48, each of the through holes 44 On the other hand, the working fluid can simultaneously flow in and out through the space within the annular groove 46.

In such a suspension bushing, when the working fluid flows into the annular groove 46 through the port 48 of the port member 18, the working fluid flows between the outer sleeve 12 and the rubber sleeve 16 through the through holes 44 of the outer sleeve 12.
Since the working fluid is caused to flow into the space between the are blocked so that the fluid chambers 32, 32 and 34,
The spring characteristics in each of the opposing directions of 34 become stiffer.

On the other hand, if the working fluid in the annular groove 46 is allowed to flow out through the port 48 of the port member 18, the working fluid will be allowed to flow out from the space between the outer cylinder fitting 12 and the rubber sleeve 16 through each through hole 44.
Each throttle passage 42 is opened. Therefore, in this case, each fluid chamber 3 is
As a result, the spring characteristics of the fluid chambers 32, 32 and 34, 34 become softer in the opposing directions.

That is, in the suspension bushing of this embodiment, by allowing the working fluid to flow in and out of the port 48 of the port member 18, the fluid chambers 32, 32
Therefore, the spring characteristics can be changed in each of the opposing directions of the fluid chambers 32, 32 and 34, 34, for example, one of the opposing directions of the fluid chambers 32, 32 and 34, 34. If one direction is set in the vertical direction of the vehicle, and the other direction (the opposing direction of the fluid chambers 34, 34) is set in the vertical direction of the vehicle, the inflow and outflow of the working fluid is controlled according to the operating state or running state of the vehicle. By changing the spring characteristics in the vertical direction of the vehicle and in the horizontal direction of the vehicle as necessary, it is possible to achieve both steering stability and ride comfort.

In the suspension bushing of this embodiment, as described above, the port 48 of the port member 18
Since the function of changing the spring characteristics as described above can be obtained simply by flowing the working fluid in and out of the port, it is only necessary to connect one piping to the port 48 of the port member 18. Therefore, compared to this type of conventional fluid-filled suspension bushing, the external piping can be greatly simplified and the space required for the external piping can be significantly reduced. Furthermore, the suspension bushing of this embodiment does not require the use of an expensive solenoid valve mechanism in order to obtain the function of varying the spring characteristics as described above, so it can be manufactured economically. be.

In addition, in the suspension bushing of this embodiment, if the throttle passage 42 is set to correspond to a desired frequency range, when the throttle passage 42 is opened, the liquid column of the incompressible fluid flowing through the throttle passage 42 will be reduced. Another advantage is that input vibrations in a desired frequency range can be well damped or blocked based on the resonance effect.

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

For example, in the suspension bushing of the above embodiment, the fluid chambers 32, 32 and 34, 34 were provided so as to face each other in two mutually orthogonal directions in the radial direction of the bushing, but the If it is only necessary to provide a variable spring characteristic function for one vibration input direction, the fluid chamber may be formed only in the direction in which such a function is required.

Further, in the embodiment described above, the through holes 44 were provided at the portions of the outer cylinder fitting 12 corresponding to the circumferentially intermediate portions of the respective throttle passages 42. Passage 42 and fluid chamber 3
It is also possible to form only one in a portion corresponding to either 2 or 34.

Further, in the above embodiment, an example was described in which the present invention was applied to a suspension bushing of an automobile suspension, but the present invention may also be applied to vibration-proof bushings other than such suspension bushings. is possible.

In addition, although it is omitted to list specific examples one by one, within the scope of the present invention without departing from the spirit thereof,
Various modifications based on the knowledge of those skilled in the art,
Things that can be implemented with modifications, improvements, etc. are:
It goes without saying.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view (- sectional view in FIG. 2) showing an example of a suspension bush of an automobile suspension according to the present invention, and FIG. 2 is a - sectional view in FIG. FIG. 3 is a - sectional view in FIG. 2. 10: Inner cylinder metal fitting (inner cylinder member), 12: Outer cylinder metal fitting (outer cylinder member), 14: Rubber elastic body, 16: Rubber sleeve (flexible membrane), 18: Port member, 22: Seal sleeve, 32 , 34: fluid chamber, 42: throttle passage, 44: through hole, 46: annular groove, 48: port.

Claims (1)

[Scope of Claims] 1. An inner cylinder member, an outer cylinder member disposed outside the inner cylinder member at a predetermined distance, and interposed between the inner cylinder member and the outer cylinder member, a cylindrical rubber elastic body that elastically connects them; a cylindrical flexible membrane interposed between the rubber elastic body and the outer cylinder member; At least a pair of pocket portions are opened to the outer circumferential surface of the body and are formed to face each other with the inner cylinder member in between,
at least a pair of fluid chambers filled with a predetermined incompressible fluid, the openings of which are closed with the flexible membrane; and a circumferential groove formed on the outer peripheral surface of the rubber elastic body. a throttle passage whose opening is closed by the flexible membrane and which allows the fluid chambers to communicate with each other; and a throttle passage corresponding to either the throttle passage or the fluid chamber of the outer cylinder member. A predetermined working fluid, which is made to flow in and out through a through hole formed in the part and a port inserted outside the outer cylinder member and opened on the outer circumferential surface, is passed through the through hole to the outer cylinder member and the flexible membrane. a cylindrical port member configured to allow the working fluid to flow in and out between the port member, and the flexible membrane is deformed based on the inflow and outflow of the working fluid through the port of the port member. A fluid-filled anti-vibration bushing characterized in that it can be opened and closed respectively.