JP3510333B2 - Cylindrical liquid filled vibration isolator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical liquid-filled vibration damping device used for an engine mount or the like, and more particularly to a liquid filled material exhibiting good vibration absorption characteristics over a wide range. It relates to a vibration isolator. 2. Description of the Related Art FIG. 5 shows a general structure of a conventional cylindrical liquid filled vibration isolator. In the figure, an inner cylinder 2 is arranged substantially coaxially in an outer cylinder 1, and an anti-vibration rubber body 3 held in a cylindrical insert plate 4 is arranged between the inner cylinder and the outer cylinder. It is set up. The anti-vibration rubber body 3 is formed by recessing the lower part of the inner cylinder 2 except for both ends in the axial direction to form a space with the outer cylinder 1, and the inside thereof is a main liquid chamber A. On the other hand, a ring-shaped throttle member 7 is provided on the outer periphery of the insert plate 4, and a thin rubber film 8 is provided so as to cover an upper opening thereof. Liquid chamber B
Is formed. The main liquid chamber A and the sub liquid chamber B are communicated with each other through an orifice 71 provided in the throttle member 7, and the sealed liquid is caused to flow through the orifice 71 so that the low frequency region, mainly the engine shake Vibration is reduced. In the above configuration, the dynamic spring constant in the idling region on the higher frequency side than the shake vibration becomes higher, and the effect of suppressing the idling vibration is small. For this reason, development of a device capable of effectively reducing vibration in a wider frequency range has been desired. For example, Japanese Patent Laid-Open Publication No. 1-126451 discloses that three liquid chambers are formed inside a rubber body, and these liquid chambers are individually provided with orifice passages. There is described an anti-vibration device in which two vibration systems are configured by communicating with each other via a plurality of vibration systems, and each vibration system absorbs different vibrations. [0005] However, in the above-mentioned conventional apparatus, the orifice passages communicating the first liquid chamber and the second and third liquid chambers are formed independently of each other.
The number of parts is large and the configuration is complicated, for example, a cylindrical member for forming the orifice passage needs to be provided between the rubber body and the outer cylindrical member. Therefore, it takes time to manufacture,
There was a problem that the production cost increased. An object of the present invention is to provide a simple structure,
An object of the present invention is to provide a cylindrical liquid filled vibration isolator which is easy to manufacture and has an excellent vibration absorbing effect in a plurality of different frequency ranges. [0007] shows the configuration of a cylindrical liquid filled vibration isolating device of the solutions for the object of the present invention in FIG. 1, arranged outer tube 1 and the inner tube 2 so that the axis direction coincides, cylinder Inner space of the insert plate 4
And an outer cylinder 1 and an inner cylinder 2
The vibration-proof rubber body 3 is disposed between them. The anti-vibration rubber body 3
A main liquid chamber A is formed between the outer cylinder 1 and a part of the main liquid chamber A. Thin rubber films 31 and 32 are formed on a plurality of other portions of the vibration-proof rubber body 3, and are separated from each other between the rubber films 31 and 32 and the outer cylinder 1. A plurality of sub liquid chambers B and C separated from the liquid chamber A are provided. Then, one of the plurality of sub liquid chambers B and C is communicated with the main liquid chamber A through the first orifice 5, and the plurality of sub liquid chambers B and C are connected through the second orifice 6.
It has been communicated. [0008] Specifically, the first orifice 5 is
The flow path length is shorter than the second orifice 6 or the flow path cross-sectional area is larger, and the first orifice has a resonance frequency on a higher frequency side than the second orifice 6 , Follow-up deformation of the first rubber film 31 constituting the chamber wall of the sub liquid chamber B communicating with the main liquid chamber A with respect to the liquid pressure
To the second rubber film forming the chamber wall of the other sub liquid chamber C
32, which is smaller than the following deformability with respect to the hydraulic pressure.
The follow-up deformability of the rubber film 31 with respect to the liquid pressure
Make the rubber film 32 less deformable than the liquid pressure.
As a measure, a protection device located behind the first rubber film 31 is provided.
The vibrating rubber body 3 acts as a stopper on the first rubber film 3.
1 is regulated. When the plurality of orifices 5 and 6 are configured so as to have different flow path lengths or flow path cross-sectional areas, the orifices 5 and 6 cause liquid resonance in different frequency regions. Therefore, for example, the flow path length of the first orifice 5 is shorter than that of the second orifice 6 or the flow path cross-sectional area is formed larger, so that the first orifice 5 has a resonance frequency on the higher frequency side than the second orifice 6. , It becomes possible to perform vibration absorption in a plurality of frequency regions. Further, by shortening the flow path length (or increasing the flow path cross-sectional area) of the first orifice 5 communicating with the main liquid chamber A, the flow resistance thereof can be reduced. Since it is relatively easy, the operation of the second orifice 6 is not hindered. Then, a rubber film 31 serving as a chamber wall of the sub liquid chamber B
Is smaller than the rubber film 32 serving as the chamber wall of the sub liquid chamber C, the liquid flows quickly from the sub liquid chamber B to the second orifice 6, and the vibration is reduced more effectively. . An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall sectional view of a cylindrical liquid-filled engine mount to which the present invention is applied, and FIGS. 2 and 3 are a longitudinal sectional view and a transverse sectional view, respectively. In FIG. 1, an inner cylinder 2 connected to a vibrating body is arranged in an outer cylinder 1 so that the inner cylinder 2 has the same axial direction as the outer cylinder 1. An anti-vibration rubber body 3 is joined and disposed between the inner and outer cylinders, and the inner cylinder 2 penetrates substantially the center of the anti-vibration rubber body 3. The outer cylinder 1 is press-fitted and fixed in a bracket (not shown), and is connected and supported by the vehicle body. The vibration-proof rubber body 3 is formed by injecting a rubber material into the inner space and the outer periphery of the cylindrical insert plate 4. The anti-vibration rubber body 3 has a concave portion reaching the inner cylinder 2 in the lower half except for both ends in the axial direction (FIG. 2), and the concave portion faces an opening provided on the peripheral surface of the insert plate 4. In. Thus, when the vibration-proof rubber body 3 is pressed into the outer cylinder 1, a main liquid chamber A having the vibration-proof rubber body 3 as a chamber wall is formed (FIG. 1). On the other hand, the insert plate 4 has an axially central portion of the upper half recessed (FIG. 2), and the vibration isolating rubber member is filled so as to fill the space between the insert plate 4 and the outer cylinder 1 above. 3
Is arranged. In the concave portion of the insert plate 4, a plurality of concave portions are formed in the anti-vibration rubber body 3 at symmetrical positions (left and right positions in FIG. 1) separated by the inner cylinder 2. The walls are formed by hollowing out the vibration-isolating rubber body 3 therebelow to form a gap, thereby forming a thin rubber film 3 respectively.
1, 32. A first auxiliary liquid chamber B having the rubber film 31 as a chamber wall is provided between the rubber film 31 and the outer cylinder 1 between the rubber film 31 and the outer cylinder 1. A second auxiliary liquid chamber C having a chamber wall 32 is formed. The vibration isolating rubber body 3 covering the outer periphery of the left side of the insert plate 4 is provided with a groove extending in the circumferential direction at the center in the axial direction, and the both ends thereof are the main liquid chamber A and the first sub liquid chamber B. To form a first orifice 5 (FIGS. 1, 3). On the other hand, the first sub-liquid chamber B and the second sub-liquid chamber C are partitioned,
A groove extending in the circumferential direction is provided in the thick portion at the upper end of the vibration isolating rubber body 3, and both ends thereof are opened to the first sub-liquid chamber B and the second sub-liquid chamber C to form the second orifice 6. (Figure 1,
2). Thus, the main liquid chamber A and the first sub liquid chamber B are
And the first sub-liquid chamber B and the second
The second orifice 6 communicates with the auxiliary liquid chamber C. The first orifice 5 has a resonance frequency on the higher frequency side than the second orifice 6 by configuring the flow path cross-sectional area to be large or the flow path length to be short. Here, the cross-sectional area of the first orifice 5 is formed relatively large so that liquid resonance occurs at a frequency (about 30 Hz) corresponding to the idling vibration of the engine. On the other hand, the second orifice 6 has a relatively small cross-sectional area so that liquid resonance occurs at a frequency (about 10 Hz) corresponding to shake vibration. The rubber film 31 forming the chamber wall of the first sub liquid chamber B is formed to be thicker than the rubber film 32 forming the chamber wall of the second sub liquid chamber C. . For this reason, the rubber film 31 has relatively high rigidity, and the sealed liquid easily flows into the second auxiliary liquid chamber C having the rubber film 32 that is more freely deformed as a chamber wall. Therefore, when the internal pressure of the first sub-liquid chamber B increases, the sealed liquid quickly flows into the second sub-liquid chamber C via the second orifice 6 and obstructs the operation of the second orifice 6. There is no. The rubber film 31 only needs to have a shape that is less likely to be deformed when a liquid pressure is applied than the rubber film 32. Instead of adjusting the film thickness, the area of the rubber film 31 is made smaller than that of the rubber film 32. Then, the rigidity of the rubber film 31 may be relatively increased. Further, in the present embodiment, the vibration-isolating rubber body 3 located behind the rubber film 31 plays a role of a stopper for restricting excessive deformation of the rubber film 31, and this stopper action causes the rubber film 31 to function as a stopper. It is not always necessary to change the film thickness or the like if the configuration is such that the deformation amount is sufficiently regulated. In the above configuration, when an idling vibration of about 30 Hz is input, the internal pressure of the main liquid chamber A increases due to the deformation of the rubber elastic body 3, and the filled liquid passes through the first orifice 5 and passes through the first sub-orifice 5. The liquid flows into the liquid chamber B. Due to the liquid resonance at this time, the dynamic spring constant in the idling region indicated by the arrow D in FIG. 4 can be greatly reduced, and the vibration can be effectively absorbed. On the other hand, when a shake vibration of about 10 Hz is input during traveling, the filled liquid is supplied from the first orifice 5 and the first sub-liquid chamber B to the second sub-liquid chamber C via the second orifice 6. Flows into. Here, the first orifice 5, which communicates the main liquid chamber A and the first sub liquid chamber B, has a large flow passage cross-sectional area and a small flow resistance. Distribution is relatively free. Further, the rubber film 31, which is the chamber wall of the first sub liquid chamber B, has high rigidity and is hardly deformed.
The second sub-liquid chamber C having a chamber wall which is more freely deformed.
, And quickly flows through the second orifice 6. Due to the liquid resonance at the time of flowing through the second orifice 6, the damping coefficient is sufficiently increased in the shake vibration region as shown by the arrow E in FIG. 4, and the vibration is effectively damped. In the above embodiment, the first orifice 5 is adjusted so as to generate liquid resonance in the idling region. However, by appropriately changing the flow path length and the sectional area of the orifice,
It is also possible to change the resonance frequency from the middle frequency to the high frequency as needed. As described above, according to the present invention, a plurality of orifices are provided, each of which absorbs vibration in a different region, thereby exhibiting excellent vibration absorption characteristics in a wide range. be able to. Further, a plurality of sub-liquid chambers are connected by an orifice, the main liquid chamber and the plurality of sub-liquid chambers are arranged in series, and a rubber film forming the sub-liquid chamber and a rubber body forming the main liquid chamber Since they are provided integrally, the configuration can be greatly simplified. Therefore, it is easy to manufacture, cost reduction is possible,
High industrial value.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall sectional view showing an embodiment of a cylindrical liquid-filled vibration isolator according to the present invention. FIG. 2 is a sectional view taken along the line II-II in FIG. FIG. 3 is a sectional view taken along line III-III in FIG. FIG. 4 is a frequency characteristic diagram of the device of the present invention. FIG. 5 is an overall sectional view of a conventional cylindrical liquid filled vibration isolator. [Description of Signs] A Main liquid chamber B First sub liquid chamber C Second sub liquid chamber 1 Outer cylinder 2 Inner cylinder 3 Anti-vibration rubber bodies 31, 32 Rubber film 4 Insert plate 5 First orifice 6 Second Orifice

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-95631 (JP, A) JP-A-2-109042 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16F 13/00-13/30

Claims (1)

(57) [Claims 1] An outer cylinder and an inner cylinder are arranged so that their axial directions coincide with each other, and a rubber material is applied to the inner space and outer periphery of the cylindrical insert plate.
Inject and place rubber vibration insulator between the outer cylinder and inner cylinder
A plurality of liquid chambers are provided within the vibration-isolating rubber body, and these liquid chambers are communicated with an orifice. A main liquid chamber is formed between the outer cylinder and a main liquid chamber, and a thin rubber film is formed at a plurality of other portions of the vibration isolating rubber body. A plurality of sub-liquid chambers partitioned from the main liquid chamber are provided, and one of the plurality of sub-liquid chambers communicates with the main liquid chamber through a first orifice. The second orifice communicates with the first orifice, and the first orifice is connected to the second orifice.
Make the flow path shorter or larger than the orifice
Wherein the first orifice is provided with the second orifice.
The first groove which has a resonance frequency on a higher frequency side than the main liquid chamber and forms a chamber wall of the sub liquid chamber communicating with the main liquid chamber.
The follow-up deformation to the hydraulic pressure of the
Following Deformability of the Second Rubber Film Constituting the Chamber Wall to Hydraulic Pressure
Smaller than the second rubber film, and the first rubber film has
To make the rubber film smaller than the deformability of the rubber film
As a step, an anti-vibration rubber positioned behind the first rubber film
The body reduces the amount of deformation of the first rubber film by the stopper action.
A cylindrical liquid-filled vibration isolator that is regulated.