JPH0726662B2 - Fluid filled type anti-vibration device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration isolator such as an automobile engine mount used for vibration-isolating and supporting a vibration body such as an engine. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid-filled type vibration damping device that absorbs vibration by elasticity and the flow of a fluid filled inside.

(Prior Art) In a vehicle, various vibrations having greatly different frequencies and amplitudes are generated depending on the operating state thereof, for example, the engine speed. Therefore, automobiles are required to use a vibration isolation device capable of absorbing a wide range of vibrations.

A fluid-filled type vibration damping device is known as such a vibration damping device. This fluid-filled type vibration damping device is a main fluid chamber in which a part of the chamber wall is formed of an elastic body such as thick rubber, and the volume of which changes in accordance with the vibration of the vibrating body, and its main flow. It is composed of an auxiliary fluid chamber communicating with the body chamber via an orifice, and an incompressible fluid such as oil is enclosed in the main and auxiliary fluid chambers. The volume of the sub-fluid chamber is easily changed by the inflow or outflow of the fluid accompanying the volume change of the main fluid chamber.

According to such a fluid filled type vibration damping device, high frequency small amplitude vibration is absorbed by elastic deformation of the elastic body, and low frequency large amplitude vibration is attenuated by the flow resistance of the fluid flowing through the orifice. Therefore, vibrations having different frequencies and amplitudes are absorbed.

By the way, even in such a fluid filled type vibration damping device,
If the orifice is a fixed orifice having a constant cross-sectional area, it is not possible to absorb a vibration in a sufficiently wide range. That is, in order to effectively absorb high-frequency, small-amplitude vibrations, it is necessary to increase the cross-sectional area of the orifice and reduce the fluid flow resistance. On the other hand, in order to effectively absorb low-frequency, large-amplitude vibrations, it is necessary to reduce the cross-sectional area of the orifice to increase the fluid flow resistance and increase the damping force. Therefore, both cannot be satisfied with the fixed orifice, and the range of vibration that can be absorbed is limited.

For this reason, in the case of a fluid filled type vibration damping device which is required to absorb a vibration in a particularly wide range such as an automobile engine mount, for example, as shown in Japanese Utility Model Laid-Open No. 60-95244. In addition, it is considered that the orifice that connects the main fluid chamber and the sub-fluid chamber with each other is a variable area orifice. In this vibration isolator, a partition wall that divides the main fluid chamber and the sub-fluid chamber is composed of a fixed plate and a rotating plate, each of which has an opening. The area of the orifice is changed by changing the area.

In the case of the vibration isolator having such a variable orifice, conventionally, each of the openings provided in the fixed plate and the rotary plate has a large opening area of substantially the same shape.

(Problems to be Solved by the Invention) However, in the case of the vibration isolator in which the fixed plate and the rotary plate are provided with the large-area openings in such a manner, it is possible to connect the main fluid chamber and the sub-fluid chamber to each other. The most narrowed portion of the passage is the overlapping portion of each opening in the sliding contact surface between the fixed plate and the rotating plate.
That is, that portion acts as a substantial orifice. Therefore, the orifice cannot have a length.

On the other hand, in the fluid filled type vibration damping device, in order to effectively absorb the high frequency vibration, it is required to reduce the dynamic spring constant of the vibration damping device. For that purpose, it is necessary to resonate the elasticity existing in the orifice portion between the main fluid chamber and the sub fluid chamber. Therefore, the orifice must be of sufficient length.

The present invention has been made in view of such a problem, and an object thereof is to make the opening area of an orifice communicating a main fluid chamber and a sub fluid chamber of a fluid filled type vibration damping device variable, The purpose is to ensure the length of the orifice.

(Means for Solving the Problems) In order to achieve this object, in the present invention, a partition for partitioning the main fluid chamber and the sub-fluid chamber is provided with a fixed plate and a rotating plate each having an opening. One of the fixed plate and the rotary plate has an opening having a large area, and the other opening has a large area. The small area opening is
It is assumed to have a sufficient axial length.

(Operation) With this configuration, when the rotating plate is rotated to change the area of the overlapping portion of the opening and the opening of the fixed plate, the number of openings of the small area is changed. .
Therefore, the total area of the orifices that connect the main fluid chamber and the sub fluid chamber changes. Moreover, since each of the small-area openings acts as an orifice, its length can be sufficiently secured.

(Examples) Examples of the present invention will be described below with reference to the drawings.

In the drawings, FIGS. 1 to 5 show an embodiment in which a fluid filled type vibration damping device according to the present invention is applied to an automobile engine mount, and FIG. 1 is a longitudinal sectional view thereof, and FIGS. FIG. 3A is a plan view and a bottom view of the housing portion. Also, the fourth and fifth
The figures are plan views of the housing part in different operating states.

As is clear from FIGS. 1 to 3, the engine mount 1 is made of a thick rubber cone-shaped elastic body 2 and a rigid material such as metal or plastic, and has a bottomed cylindrical shape with an open lower end. And a housing 3 of. A mounting member 4 for mounting an engine, which is a vibrating body, is vulcanized and bonded to the upper end of the elastic body 2. A ring-shaped flange member 5 is vulcanized and adhered to the lower end of the elastic body 2, and the elastic body 2 is attached to the housing 3 by the flange member 5. The housing 3 is attached to the vehicle body frame by a bracket 6 fixed to the lower end of the housing 3. Thus, the elastic body 2 supports the engine, which is a vibrating body, and is elastically deformable in response to the vibration.

On the lower surface of the flange member 5, the inner and outer double seal rings 7,
7 is provided so that the flange member 5 and the housing 3 are liquid-tightly sealed. The lower end opening of the housing 3 is liquid-tightly sealed by a flexible diaphragm 8 made of thin rubber. Thus, a space that is liquid-tightly surrounded by the elastic body 2, the housing 3, and the diaphragm 8 is formed inside the engine mount 1.

The upper bottom wall of the housing 3 is formed as a thick fixing plate 9. A thin rotating plate 10 is superposed on the upper surface of the fixed plate 9. This rotating plate 10 is a fixed plate 9
A support shaft 11 which is rotatably supported at the center of the base plate supports the lower surface of the support shaft 11 so that the lower surface thereof can be slidably contacted with the upper surface of the fixed plate 9 and can be rotated about the central axis. Thus
The fixed plate 9 and the rotating plate 10 form a partition wall 12 that vertically divides the liquid-tight space in the engine mount 1.

The main fluid chamber 13 formed above the partition wall 12 has a chamber wall partially formed by the elastic body 2, and the volume thereof is changed by the deformation of the elastic body 2 due to the vibration of the engine. The volume of the sub-fluid chamber 14 formed below the partition 12 is easily changed by the deformation of the diaphragm 8. Then, an incompressible fluid such as oil or water is sealed inside the main and sub fluid chambers 13 and 14.

On the outer peripheral portion of the fixed plate 9, that is, on the inner peripheral portion of the peripheral wall 3a of the housing 3, an arc-shaped guide groove 15 extending over a range slightly longer than half the entire circumference is provided on the upper surface.
An arcuate projection 16 that projects downward from the outer peripheral portion of the rotating plate 10 is inserted into the guide groove 15.
The projection 16 extends over a range of approximately 90 °, and a rack 17 is formed on the lower end surface thereof. A pinion gear 18 is engaged with the rack 17. The pinion gear 18 is provided on the peripheral wall 3a of the housing 3.
It is adapted to be rotationally driven by an actuator (not shown) installed outside the housing 3 via a drive shaft 19 penetrating therethrough. The actuator is controlled by a control signal based on the engine speed, the relative displacement between the engine and the vehicle body, and the like. Thus, the rotating plate 10 is rotated within a range of about 90 ° with respect to the fixed plate 9.

The fixed plate 9 is provided with an opening 21 that is a collection of a large number of small-diameter circular openings 20, 20, .... The opening 21 is a fan-shaped region that is substantially symmetrical with respect to the central support shaft 11 and has a central angle slightly smaller than 90 °. And that opening 20
Is relatively long in the axial direction and vertically penetrates the thick fixing plate 9. Also, on one side of the opening 21,
A wall portion 22 that extends from the lower surface of the fixed plate 9 to the vicinity of the lower end portion of the housing 3 is provided, and a small-area fan-shaped through hole 23 that vertically penetrates is formed in the wall portion 22.

On the other hand, the rotating plate 10 is provided with an opening 24 corresponding to the opening 21 of the fixed plate 9. The openings 24 are two large-area openings 25, 25, which are fan-shaped and have a central angle of about 90 ° and are provided at intervals of about 90 °.

In this way, by rotating the rotating plate 10, the area of the overlapping portion of the opening 24 and the opening 21 of the fixed plate 9 is changed.

A thin groove 26 extending in the circumferential direction is formed on the outer peripheral portion of the upper surface of the housing 3. The upper surface of the groove 26 is sealed by the portion of the flange member 5 between the seal rings 7, 7. Then, one end of the groove 26 is open to the main fluid chamber 13 via a cutout groove 27 provided in a part of the lower portion of the elastic body 2 and the flange member 5 in the circumferential direction. Further, the other end of the groove 26 is provided with the peripheral wall 3a of the housing 3.
It is adapted to communicate with the auxiliary fluid chamber 14 through a communication hole 28 formed in the. Thus, the groove 26 and the communication hole 28 form a fixed orifice 29 that allows the main fluid chamber 13 and the auxiliary fluid chamber 14 to communicate with each other at all times. This fixed orifice 29
Has a small cross-sectional area and is sufficiently long, and when vibration with a very large amplitude such as a shake is applied to the engine mount 1, it imparts a great flow resistance to the fluid flowing therethrough and reliably damps the vibration. Is set to let.

Next, the operation of the fluid filled engine mount 1 configured in this way will be described.

When the engine is stopped, the rotating plate 10 is held at a position where its opening 24 is 90 ° out of phase with the opening 21 of the fixed plate 9, as shown in FIG. Therefore, the openings 20, 20, ... And the through holes 23 of the fixing plate 9 are all in a closed state.

When the engine is started and the engine enters the idle state, the actuator is operated and the rotating plate 10 is rotated clockwise by a small angle in FIG. As a result, as shown in FIG. 4, the opening 25 of the rotating plate 10 overlaps the through hole 23 of the fixed plate 9, and the through hole 23 is opened. Therefore, the main fluid chamber 13 and the sub fluid chamber 14 communicate with each other through the through hole 23.

When idling, the engine vibrates with low frequency and large amplitude. Therefore, the elastic body 2 is deformed relatively greatly with the vibration, and the main fluid chamber 13 expands and contracts. As a result, the fluid flows between the main fluid chamber 13 and the sub fluid chamber 14. At this time, the main fluid chamber 13 and the sub-fluid chamber 14 are communicated with each other through the fixed orifice 29, but the fixed orifice 29 is a through hole.
Since it is longer than 23 and the cross-sectional area is small, the flow resistance is high. Therefore, at this time, the fluid is mainly through holes.
Flow through 23. That is, the through hole 23 serves as an orifice for restricting the fluid flowing between the main fluid chamber 13 and the sub fluid chamber 14. The through hole 23 has a constant cross-sectional area and is relatively long in the axial direction. Therefore, the mass of fluid present in the orifice will be large,
The fluid has resonance enough to absorb the vibration at that time.

In this way, engine vibration during idling is absorbed.

When the rotational speed of the engine increases, the rotating plate 10 is further rotated according to the rotating speed, and the opening 21 of the fixed plate 9 and the opening 24 of the rotating plate 10 overlap each other, as shown in FIG. It becomes a state. In this state, the plurality of openings 20, 20, ...
Is opened. Therefore, the main fluid chamber 13 and the sub-fluid chamber 14 communicate with each other through these openings 20, 20 ,. That is, the total area of the communication passages communicating between the main and sub fluid chambers 13 and 14 is large. Moreover, each of these openings 20, 20, ... acts as a relatively long orifice having a constant cross-sectional area. As a result, the resonance of the fluid occurs in the orifice that communicates the main and sub fluid chambers 13 and 14, the dynamic spring constant of the engine mount 1 is reduced, and the high frequency small amplitude vibration at that time is effectively absorbed. Will be done.

In this case, the opening to be opened according to the turning angle of the turning plate 10.
The number of 20 changes and the dynamic spring constant changes. Therefore,
By rotating the rotating plate 10 in accordance with the change in the engine speed, it is possible to absorb the vibration that changes according to the engine speed in the high rotation range of the engine.

When a vibration with an extremely large amplitude such as a shake is generated, it is detected by the displacement sensor or the acceleration sensor, and the actuator is actuated by the signal, and as shown in FIG. , ...
And the through hole 23 is closed. In that state,
The main fluid chamber 13 and the sub-fluid chamber 14 communicate with each other only through the fixed orifice 29 having a large flow resistance. Therefore, a large damping force acts on the fluid flowing between the main and sub fluid chambers 13 and 14, and the vibration having an extremely large amplitude at that time is absorbed.

In the above embodiment, the axial lengths of the openings 20 provided in the fixed plate 9 are all constant, but the orifice may be short when the vibration frequency is high. Therefore, as shown in FIG. 6, the opening 20 opened by turning the turning plate 10 at a small angle is long in the axial direction, and the opening 20 opened only when it is turned largely is shortened. You can also By doing so, the change in the dynamic spring constant from the idle range to the high rotation range can be made smooth. Further, in that case, the rate of change in the axial length of the opening 20 can be made different depending on the rotation angle of the rotation plate 10. Further, the area of the opening 20 may be gradually changed.

FIG. 7 is a plan view of a housing portion showing still another embodiment of the fluid filled type vibration damping device according to the present invention.

In this embodiment, the opening 21 provided in the fixed plate 9
Is a fan-shaped region close to a semi-circle. The opening 21 is formed by a honeycomb-structured plate 30 that is an assembly of a large number of small-area openings 20, 20, .... The plate 30 has a large plate thickness.

On the other hand, the opening 24 provided in the rotating plate 10 is also a fan-shaped opening 25 corresponding to the opening 21 of the fixed plate 9.

Even in such a case, the number of openings 20 to be opened changes depending on the turning angle of the turning plate 10. Therefore, it is possible to obtain the same effect as that of the above-mentioned embodiment. And
By adopting the honeycomb structure, it is possible to secure a sufficiently large opening area.

In any of the above embodiments, the opening 21 provided in the fixed plate 9 is a collection of a large number of openings 20, 20, ... And the opening 24 provided in the rotating plate 10 is a large area opening 25. Although it is formed, it can be reversed.
In that case, the fixed plate 9 may be thin and the rotating plate 10 may be thick.

Further, such a fluid filled type vibration damping device can be applied not only to an engine mount for an automobile but also to a mount for a suspension or the like.

(Effects of the Invention) As is apparent from the above description, according to the present invention, one of the openings provided in the fixed plate and the rotary plate is a large-area opening, and the other of the openings is a large number. Is formed as a collection of small area openings, and the number of opened small area openings is changed according to the turning angle of the turning plate. It is possible to secure the length of the orifice while making the total area of the communicating orifice variable. Therefore,
Resonance can be generated in the fluid existing in the orifice portion so that the vibration can be effectively absorbed. Moreover, since it suffices to provide the fixed plate and the rotary plate with openings respectively, the processing thereof is facilitated.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment in which a fluid filled type vibration damping device according to the present invention is applied to an automobile engine mount, and FIG. 2 is the engine as seen from the line II-II in FIG. FIG. 2 is a plan view of the housing portion of the mount, FIG. 3 is a bottom view of the housing portion taken along the line III-III of FIG. 1, and FIG. 4 is a view showing different operating states of the engine mount. 5 is a plan view similar to FIG. 5, FIG. 5 is a plan view similar to FIG. 2, showing a different operating state of the engine mount, and FIG. 6 is another embodiment of the fluid filled type vibration damping device according to the present invention. FIG. 7 is a cutaway perspective view of a main part of the housing, and FIG. 7 is a plan view similar to FIG. 2, showing a further different embodiment of the fluid filled type vibration damping device according to the present invention. 1 ... Engine mount (fluid-filled type vibration damping device) 2 ... Elastic body, 3 ... Housing 8 ... Diaphragm, 9 ... Fixed plate 10 ... Rotating plate, 12 ... Partition wall 13 ... Main fluid chamber , 14 …… Sub fluid chamber 20 …… Opening, 21 …… Opening 23 …… Through hole, 24 …… Opening 25 …… Opening, 29 …… Fixed orifice

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-73146 (JP, A) JP-A-63-62929 (JP, A) Actual development Sho-60-95244 (JP, U)

Claims (1)

[Claims] 1. A main fluid chamber in which a part of a chamber wall is formed by an elastic body supporting a vibrating body, and the volume is changed by deforming the elastic body in response to vibration of the vibrating body, A fluid-filled type vibration damping device comprising: a sub-fluid chamber, which is partitioned from the main fluid chamber by a partition wall and whose volume is changed by the flow of the internal filled fluid accompanying the volume change of the main fluid chamber. The partition wall is composed of a fixed plate and a rotary plate that rotates while slidingly contacting the fixed plate, and the fixed plate and the rotary plate overlap with each other according to the rotary angle of the rotary plate. Each of the openings of which the area of the portion changes is provided, and one of the openings of the fixed plate and the rotary plate is made a large area opening, and the other opening is made in the axial direction more Long and smaller than the large area opening Is formed as a collection of a large number of openings, the fluid filled type vibration damping device.