JPH0729320Y2 - Fluid filled bush - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a fluid-filled bush of a type in which an elastic rubber is interposed between an inner cylinder and an outer cylinder used for a suspension arm mounting portion of an automobile or the like. Regarding the improvement of.

(Prior Art) Conventionally, a fluid-filled bush of a type in which an elastic rubber is interposed between an inner cylinder and an outer cylinder used in, for example, a suspension arm mounting portion of an automobile generally has a state in which an orifice is in communication. Since it is fixed, the vibration damping effect can be exhibited only in a single vibration frequency range. Therefore, there is a problem that the conventional general fluid-filled bush cannot obtain an effective vibration damping effect in a plurality of vibration frequency ranges.

As a fluid-filled bush that solves such a problem, for example, an apparatus disclosed in JP-A-63-176843 is known. This conventional example is provided with a first orifice that constantly communicates between two fluid chambers and a second orifice whose opening and closing are controlled by a rotary valve, and provides two types of vibration frequency ranges depending on the opening / closing state of the second orifice. It is possible to obtain appropriate vibration damping characteristics.

(Problem to be Solved by the Invention) However, in the above-mentioned conventional example, the elastic stopper for preventing excessive deformation of the fluid chamber is arranged in the center of the fluid chamber, and the opening and closing is controlled by the rotary valve. The second one is also arranged in the center so as to penetrate the elastic stopper and open to the fluid chamber.
While there is a disadvantage that the processing for providing the orifice becomes complicated, in order to secure the strength of the elastic stopper, the diameter of the second orifice cannot be extremely increased and it is inevitable that the orifice diameter is set large. There is also a drawback that the elastic protrusions are large in size and the size of the device is increased.

Further, when the inner cylinder is cantilevered with respect to the mounting member, disposing the elastic stopper at the center of the fluid chamber is not always the optimum arrangement.

(Means for Solving the Problems) The present invention was devised to solve the above problems, and includes an elastic rubber interposed between an inner cylinder and an outer cylinder, the inner cylinder and the outer cylinder. And a pair of fluid chambers that are provided between the fluid chambers and are opposed to each other with the inner cylinder interposed therebetween, and a communication passage that is formed in the inner cylinder so as to communicate between the pair of fluid chambers, A rotary valve which is housed in the inner cylinder so as to be rotatable in the circumferential direction of the inner cylinder and is provided so as to open and close the communication passage; a drive device for varying the rotational displacement position of the rotary valve; An elastic stopper provided on the elastic rubber and protruding in the radial direction in the fluid chamber to prevent excessive deformation of the fluid chamber, and the inner cylinder is fixed to only one end side so as to be cantilevered with respect to the mounting member. Has a section,
The elastic stopper is arranged offset from the axial center of the fluid chamber to the fixed portion side, and the communication passage is adjacent to the elastic stopper offset to the side opposite to the elastic stopper. This is a fluid-filled bush.

(Operation) According to the present invention, the opening / closing of the communication passage can be controlled by adjusting the rotational position of the rotary valve that opens / closes the communication passage formed in the inner cylinder so as to communicate between the pair of fluid chambers. As a result, the vibration absorbing characteristics of the fluid-filled bush can be changed.

Further, the inner cylinder has a fixed portion only on one end side and cantilevered with respect to the mounting member, and the elastic stopper is arranged offset from the axial center of the fluid chamber to the fixed portion side. Therefore, it is possible to efficiently prevent excessive deformation of the fluid chamber, which is also advantageous from the viewpoint of securing the strength of the elastic support portion.

Further, since the elastic stopper is offset as described above and the communication passage communicating between the pair of fluid chambers is offset to the side opposite to the elastic stopper and is provided adjacent to the elastic stopper, the communication passage is formed. Is easy to process, and it is easy to adopt a relatively large diameter for the communication passage.
With a compact structure, it is possible to set the vibration absorption characteristics when the communication path is open up to a high frequency.

Embodiment An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 4 is a plan view schematically showing a front suspension to which the fluid sealing bush 1 according to this embodiment is applied. In FIG. 4, a lower arm 2 formed in an inverted L-shape has its outer end pivotally attached to the lower end of a knuckle (not shown) that rotatably supports the right front wheel, and its inner end on the front side is a bush 3 known per se. It is pivotally attached to a vehicle body (not shown) via. The above-mentioned fluid sealing bush 1 is provided at the inner rear end of the lower arm 2. The fluid-filled bush 1 has an inner cylinder side bolted to a flange 4 formed at the rear end of the lower arm 2, and the outer cylinder side is fixed to a vehicle body (not shown) via a bracket 5. Has become.

FIG. 1 is a sectional view showing a detailed structure of the fluid-filled bush 1. The inner cylinder 6 is integrally formed with a large-diameter flange 7 on one end side, and this flange 7 is butted against the flange 4 on the lower arm 2 side indicated by the two-dot chain line in FIG. It is fixed by bolts and nuts. Further, on the other end side of the inner cylinder 6, a valve accommodating hole 8 that opens to the other end surface is formed along the axial center. Inner cylinder 6
A ring-shaped elastic rubber 9 is fixed to the outer peripheral side by a method such as vulcanization adhesion. Recesses 12 and 13 for forming a pair of fluid chambers 10 and 11 are provided symmetrically with respect to the central axis of the inner cylinder 6 on the outer peripheral side of the elastic rubber 9. Furthermore, elastic rubber 9
A metal sleeve 14 is secured to the outer peripheral surface of the metal sleeve 14 by a method such as vulcanization adhesion, and the metal sleeve 14 has windows corresponding to the openings of the recesses 12 and 13 described above. Then, the outer cylinder 15 is press-fitted onto the outer peripheral side of the metal sleeve 14, whereby the openings of the recesses 12 and 13 are closed and the fluid chambers 10 and 11 are formed.

Further, a communication passage 16 for communicating between the fluid chambers 10 and 11 is formed in the inner cylinder 6 so as to penetrate the valve storage hole 8 in the direction perpendicular to the axis of the inner cylinder 6, and The passage 16 is arranged along the wall surfaces of the fluid chambers 10 and 11 located on the other end side of the inner cylinder 6. An orifice communication passage 17 is also bored in the inner cylinder 6, and the orifice communication passage 17 further extends from the bottom of the valve housing hole 8 to the one end side of the inner cylinder along the central axis of the inner cylinder 6. Fluid chamber that bends and extends in the direction perpendicular to the axis
And is opened along the wall surface of the fluid chamber 10 located on one end side of the inner cylinder 6.

On the other hand, the rotary valve 18 accommodated in the valve accommodating hole 8 of the inner cylinder 6 is arranged so as to be rotatable in the valve accommodating hole 8 and is connected to the other end of the inner cylinder 6 by a bolting stepping motor 19. It is connected to the output shaft 20 and its rotational position is adjusted by the operation of the motor 19. A communication hole 21 corresponding to the communication passage 16 of the inner cylinder 6 is bored in the rotary valve 18 in a direction perpendicular to the axis. Further, an orifice passage 22 corresponding to the orifice communication passage 17 is also formed in the rotary valve 18, and one opening of this orifice passage 22 is located in the middle of the two openings of the communication hole 21. An opening is made in the peripheral surface of the valve 18, and one of the openings extends in a direction perpendicular to the axis of the rotary valve 18 and is once connected to the communication hole 21,
It further extends along the central axis of the rotary valve 18 through the communication hole 21, and the other opening opens at the shaft end of the rotary valve 18. For this reason, the rotary valve 18
The opening of the orifice passage 22 opening at the shaft end of the valve is opposed to the opening of the orifice communication passage 17 on the valve housing hole 8 side so that the orifice communication passage 17 and the orifice passage 22 are always communicated with each other. Has become.

Further, as shown in FIG. 2, the elastic rubber 9 is provided with a pair of fixed orifice passages 23 and 24 extending in the circumferential direction and always communicating between the fluid chambers 10 and 11 symmetrically with respect to the central axis. Has been done. Further, the elastic rubber 9 has elastic stoppers 25 and 26 for preventing excessive deformation protruding from the recesses 12 and 13 in the outer diameter direction, and the elastic stopper 25 has an opening of the communication passage 16 and an orifice communication passage 17. Located in the recess 12 (in the fluid chamber 10) in the circumferential direction, the elastic stopper 26 is axially symmetrical to the elastic stopper 25 in the recess 12 (the fluid chamber). (Within 10).

Further, as is apparent from FIG. 1, the communication passage 16 is arranged offset to the motor 19 side with respect to the axial center of the fluid sealing bush 1 (fluid chambers 10, 11). Also, the elastic stoppers 25 and 26 are the fluid-filled bush 1.
It is arranged offset to the flange 7 side with respect to the axial center of the (fluid chambers 10, 11). Also,
As shown in FIG. 3, a long hole-shaped bolt insertion hole 27 is formed in the flange 7, and the flange 4 on the lower arm 2 side is formed.
The fastening angle with can be adjusted.

In FIG. 1, 28 is an oil seal, 29 is a snap ring, and the stepping motor 19 is a driving device.

According to the above configuration, the motor 19 is driven to rotate the rotary valve 18 in the counterclockwise direction in FIG. 2 from the state shown in FIGS.
When rotated by 90 °, the pair of fluid chambers 10 and 11 are brought into communication with each other via the communication hole 21 and the communication passage 16, and the fluid chamber 10
The fluid chamber 11 and the fluid chamber 11 are communicated not only by the fixed orifice passages 23 and 24 but also by the communication passage 16 and the communication hole 21 to obtain the first characteristic as shown in FIGS. Therefore, as shown in FIGS. 5 and 6, the vibration transmission force can be effectively reduced for relatively high frequencies, and the muffled noise of the vehicle can be effectively reduced.

Further, when the rotary position of the rotary valve 18 is adjusted by the motor 19 to the state shown in FIGS. 1 and 2, the communication between the two fluid chambers by the communication hole 21 is blocked, but the rotary valve 18 is provided. The fluid chambers 10 and 11 are communicated with each other through the orifice passage 22 and the orifice communication passage 17 provided in the inner cylinder 6, and the fluid chamber 10 and the fluid chamber 10 are communicated by the fixed orifice passages 23 and 24. In addition, the orifice passage 22 and the orifice communication passage 17 are communicated with each other. Since the orifice passage 22 and the orifice communication passage 17 have a smaller diameter than the communication hole 21, the first characteristic different from the first characteristic described above is obtained. The characteristic 2 can be obtained, and as shown in FIGS. 5 and 6, the vibration transmission force can be effectively reduced for a relatively low vibration frequency, and the riding comfort of the vehicle can be effectively improved.

Further, when the motor 19 is driven and the rotary valve 18 is rotated 180 ° from the state shown in FIGS. 1 and 2, the communication between the fluid chambers by the communication hole 21 is cut off, and the orifice passage
Since 22 communicates with the fluid chamber 10 with which the orifice communication passage 17 communicates, the orifice passage 22 and the orifice communication passage 17
The communication between both fluid chambers due to is also cut off. Therefore, the fluid chamber 10 and the fluid chamber 10 are communicated with each other only by the fixed orifice passages 23 and 24, and it is possible to obtain the third characteristic different from the first and second characteristics described above. As shown in FIGS. 5 and 6, the damping coefficient increases for extremely low vibration frequencies, low-frequency vibrations can be efficiently damped, and shimmy and the like can be effectively reduced.

According to the above-described embodiment, the orifice passage 22 that opens to the shaft end of the rotary valve 18 is provided, and the shaft end opening of the orifice passage 22 and the fluid chamber 10 are provided by the orifice communication passage 17 provided in the inner cylinder 6. Because it always communicates, it is a communication passage
The 16 and the orifice communication passage 17 can be arranged so as to be offset from each other in the axial direction of the inner cylinder 6, and the above three types of vibration absorption characteristics can be obtained with a relatively compact structure without greatly enlarging the outer diameter. Produce an effect.

Further, since the fluid-filled bush 1 is connected to the lower arm 2 by the flange 7 provided on one end side of the inner cylinder 6, it is extremely easy to assemble, and the assembling to the vehicle body and the replacement work are easily performed. be able to.

Further, the fluid-filled bush 1 cantilevers the lower arm 2, but the elastic stoppers 25 and 26 are arranged offset to the flange 7 side (lower arm 2 side) with respect to the axial center of the fluid-filled bush 1. Therefore, the stopper function can be effectively exerted against an excessive input input from the lower arm 2 side, and there is an advantage in strength. Further, since the elastic stoppers 25, 26 are arranged offset, the diameter of the communication passage 16 can be made large with a compact structure, and setting up to a high frequency can be easily performed, so that good vibration absorption is possible over a wide frequency range. The effect that the characteristics can be efficiently obtained is obtained. Along with this, the communication passage 16 is arranged offset to the motor 19 side with respect to the axial center of the fluid sealing bush 1, so that the communication passage 16 communicates with the motor 19 fixed to the other end of the inner cylinder 6. Since the distance from the passage 16 can be shortened, the length of the rotary valve 18 can be shortened, and the weight of the movable member can be reduced, the responsiveness of the device can be improved. In addition, elastic stopper 2
Since the communication passage 16 is formed adjacent to the 5, 26, there is also an advantage that the communication passage 16 can be easily processed.

It should be noted that the present invention is not limited to the above-described embodiment, and may be used, for example, as a bush used in a rear suspension, or may be replaced with a cantilever structure by flange connection, and an axially screwed connection method may be used. It goes without saying that a connecting structure using bolts screwed in the above-mentioned right angle direction may be used, and various modifications can be made within the range not departing from the gist of the present invention.

(Effects of the Invention) As described above in detail with the embodiments, according to the present invention, excessive deformation can be efficiently prevented against an excessive input in the cantilever support, and the communication passage can be processed. Easy,
Moreover, it is possible to easily provide a large diameter of the communication passage and to provide a compact fluid-sealed bush capable of obtaining efficient vibration absorption characteristics up to high frequencies.

[Brief description of drawings]

1 is a horizontal sectional view showing an embodiment of the present invention, FIG. 2 is a view taken along the line II-II in FIG. 1, FIG. 3 is a view taken along the line III-III in FIG. 1, and FIG. FIG. 5 is a schematic plan view of the front suspension showing the mounting state of the fluid filled bush 1, FIG. 5 is a characteristic diagram showing dynamic spring characteristics corresponding to each switching state, and FIG. 6 is a characteristic diagram showing damping characteristics corresponding to each switching state. Is. 1 ... Fluid sealing bush, 6 ... Inner cylinder, 7 ... Flange 9 ... Elastic rubber, 10, 11 ... Fluid chamber, 15 ... Outer cylinder 16 ... Communication passage, 17 ... Orifice communication passage 18 ... Rotary valve 19 ... Stepping motor 21 ... Communication hole, 22 ... Orifice passage 23, 24 ... Fixed orifice passage 25, 26 ... Elastic stopper

Claims (1)

[Scope of utility model registration request] 1. An elastic rubber interposed between an inner cylinder and an outer cylinder, and an elastic rubber provided between the inner cylinder and the outer cylinder and separated by the elastic rubber to face each other with the inner cylinder interposed therebetween. A pair of fluid chambers, a communication passage formed in the inner cylinder so as to communicate between the pair of fluid chambers, and the communication passage housed in the inner cylinder so as to be rotatable in the circumferential direction of the inner cylinder. And a drive device for varying the rotational displacement position of the rotary valve, and an excessive deformation of the fluid chamber that is provided on the elastic rubber and projects radially in the fluid chamber. The inner cylinder has a fixing portion only on one end side so as to be cantilevered with respect to the mounting member, and the elastic stopper has the fixing portion from the axial center of the fluid chamber. It is arranged offset to the side and the communication passage is Fluid-filled bushing, characterized in that the offset to the opposite side is provided adjacent to the elastic stopper is an elastic stopper