JP3539892B2 - Liquid filled type vibration damping device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement in a fluid filled type vibration damping device provided in a portion where an engine or a suspension of an automobile is mounted on a vehicle body, for example.
[0002]
[Prior art]
Japanese Patent Laying-Open No. 60-34541 describes an example of a conventional liquid-filled type vibration damping device. Referring to FIG. 7, the liquid filled type vibration damping device includes an inner cylinder 1 and an outer cylinder 2 which are coaxially arranged, and a connecting portion 3 which elastically connects the inner and outer cylinders 1 and 2. , Are roughly configured. An appropriate working liquid is sealed in a space 4 formed between the inner and outer cylinders 1 and 2, specifically, a plurality of liquid chambers 4a communicating with each other via an orifice passage 4b. The vibration transmission is attenuated by utilizing the resonance action of the liquid.
[0003]
In order to prevent excessive vibration in the vertical direction in FIG. 7, a stopper 5 is provided on the outer periphery of the inner cylinder 1 so as to protrude in the radial direction to regulate the relative movement of the inner and outer cylinders 1 and 2 within a predetermined range. ing. Further, in order to avoid direct contact between the metal outer cylinder 2 and the stopper 5, a rubber stopper rubber 6 is coated in a thin film on the tip of the stopper 5 that contacts the inner circumference of the outer cylinder 2. Have been. The connecting portion 3 and the stopper rubber 6 are integrally formed of an appropriate rubber material.
[0004]
[Problems to be solved by the invention]
In such a liquid-filled type vibration damping device, the spring constant after the stopper rubber 6 of the stopper 5 comes into contact with the outer cylinder 2 due to excessive vibration input or the like increases rapidly, so that, for example, a tapping sound and an abnormal sound due to the contact are generated. There is a problem of inviting.
[0005]
As a countermeasure, it is conceivable to increase the thickness of the stopper rubber 6 to reduce the spring constant. However, there is a possibility that the stopper's original function of restricting the relative movement of the inner and outer cylinders 1 and 2 to a predetermined range may be hindered. Is not preferred.
[0006]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a novel liquid-filled type that can easily and effectively reduce the occurrence of tapping noise and abnormal noise due to contact between a stopper rubber of a stopper and an inner periphery of an outer cylinder. It is intended to provide an anti-vibration device.
[0007]
[Means for Solving the Problems]
The liquid filled type vibration damping device according to the present invention includes an inner cylinder and an outer cylinder arranged coaxially, a connecting portion for elastically connecting the inner and outer cylinders, and a relative movement of the inner and outer cylinders within a predetermined range. A stopper protruding radially from the outer periphery of the inner cylinder, and a stopper rubber coated on the tip of the stopper. Further, a liquid is sealed in a space formed between the inner and outer cylinders, and vibration transmission is reduced by utilizing the resonance action of the liquid.
[0008]
The invention of claim 1 is characterized in that a lubricant is previously attached to the surface of the stopper rubber which comes into contact with the inner periphery of the outer cylinder at the time of vibration.
[0009]
According to the first aspect of the present invention, the hysteresis width of the static load-deflection characteristic at the contact portion is relatively small because the contact portion between the surface of the stopper rubber and the inner periphery of the outer cylinder relatively easily slips. It is reduced accordingly. As a result, it is possible to reduce the occurrence of a tapping sound and an abnormal sound due to the contact.
[0010]
The lubricant is preferably insoluble in the liquid in the space and excellent in lubricity and durability. Specifically, DM (dimethyl silicon) and MPh (methyl phenyl ketone) are mainly used. Grease, oil and emulsion as components can be used. Particularly preferred is silicon grease containing DM as a main component.
[0011]
Further, as in the present invention, a large number of uneven portions are formed on the surface of the stopper rubber , and each uneven portion has a columnar convex portion, and an annular concave portion formed around the convex portion, , It is possible to substantially increase the adhesion (application) area of the lubricant. As a result, it is possible to more reliably suppress the generation of a tapping sound and an unusual noise due to the contact between the stopper rubber and the outer cylinder, and it is possible to suppress the deterioration of the lubricant with time, and to maintain the initial performance for a long time. .
[0012]
When the uneven portion is formed in a streak shape extending in the axial direction of the inner cylinder, for example, the durability of the stopper rubber itself is improved as compared with the case where the uneven portion is formed along the circumferential direction, and specifically, The frequency of occurrence of cracks in the stopper rubber is reduced, and the initial vibration-proof function can be maintained for a long period of time.
[0013]
【The invention's effect】
As described above, according to the present invention, it is possible to easily and effectively reduce the occurrence of hitting noise and abnormal noise due to the contact between the stopper rubber of the stopper and the inner periphery of the outer cylinder.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
1 and 2 show an embodiment of a liquid-filled type vibration damping device according to the present invention. This liquid filled type vibration damping device is applied to a portion where a differential device for changing the rotation direction and the gear ratio of a propeller shaft and a drive shaft of an FR vehicle or a 4WD vehicle is mounted on a vehicle body side. As shown in (1), it is mounted on the vehicle body in a horizontal position, and has a vibration damping function and a vibration damping function mainly for vertical vibration.
[0015]
In this liquid-filled vibration damping device, a metal cylinder 10 having a low cylindrical shape attached to a propeller shaft side and a cylindrical metal outer cylinder 12 fixed to a cross member on the vehicle body side are coaxial. The inner and outer cylinders 10 and 12 are elastically connected in the radial direction by a connecting portion 14 made of an elastic material such as rubber.
[0016]
Reference numeral 16 denotes a metal intermediate cylinder which is integrally sulfur-bonded to the connection part 14 together with the inner cylinder 10 when the connection part 14 is subjected to sulfur molding. At the time of manufacturing, after the inner cylinder 10 and the intermediate cylinder 16 integrated with the connecting portion 14 are fitted into the outer cylinder 12, both ends of the outer cylinder 12 are bent inward and fixed.
[0017]
A space 18 formed between the inner and outer cylinders 10 and 12, more specifically, a plurality of liquid chambers 18b communicating with each other through an orifice passage 18a contains ethylene glycol, water, propylene glycol, or the like as a main component. An appropriate liquid is sealed therein, and the vibration transmission is attenuated by utilizing the resonance action of the liquid. In order to form the above-mentioned orifice passage 18a, an appropriate concave portion 16a is bent at the axial center of the intermediate cylinder 16.
[0018]
Further, a resin (or metal) stopper 20 is fixed to the axial center of the inner cylinder 10. The stopper 20 has a pair of protrusions 22 projecting in a diameter direction along the vibration direction so as to restrict the relative movement of the inner and outer cylinders 10 and 12 in a predetermined vibration direction (vertical direction in FIG. 1) within a predetermined range. have. The distal end (surface) of the protruding portion 22 facing the inner periphery of the outer cylinder 12 via a predetermined gap is covered with a stopper rubber 24 as an elastic body. The stopper rubber 24 is formed integrally with the connecting portion 14 in this embodiment, in other words, forms a part of the connecting portion 14.
[0019]
In addition, in order to reliably restrict the relative movement range of the inner and outer cylinders 10 and 12 mainly at the distal end of each protruding portion 22, the metal protruding portion 22 is disposed radially outward at the center in the circumferential direction. The most protruding portion 22a is formed, and the stopper rubber 24 covering the protruding portion 22a is relatively thin. In addition, the stopper rubbers 24 located on both sides in the circumferential direction of the overhang portion 22a are relatively thickened so as to securely contact the inner periphery of the outer cylinder 12 and appropriately absorb the impact at the time of contact. At the same time, it protrudes radially outward from the central portion in the circumferential direction.
[0020]
In the present embodiment, a suitable lubricant for reducing the frictional resistance with the inner circumference of the outer cylinder 12, more specifically, silicon grease, is provided in advance on the surface of the stopper rubber 24 which comes into contact with the inner circumference of the outer cylinder 12 at the time of vibration input. Coated and adhered. That is, on the surface of the stopper rubber 24, a thin-film lubricating layer 26 made of the above-mentioned lubricant is formed.
[0021]
Further, an appropriate uneven portion is formed in advance on the surface of the stopper rubber 24 to which the lubricant is applied. 4A and 4B show the uneven portion 28 according to the first reference example, wherein FIG. 4A is a view corresponding to arrow B in FIG. 1 and FIG. 4B is an enlarged view of a main part. The projections and depressions 28 project from the surface of the stopper rubber 24 in a substantially semicircular cross section and are formed in a plurality (four in this embodiment) of streaks extending along the axial direction of the inner cylinder 10. .
[0022]
Next, the operation and effect of this embodiment will be described with reference to the load-deflection characteristic diagram of FIG. In addition, the broken line (a) of FIG. 3 shows the present example in which silicon grease was applied to the surface of the stopper rubber, and the solid line (b) shows the comparative example in which silicon grease was not applied to the surface of the stopper rubber. I have.
[0023]
In the non-contact region R1 in which the stopper rubber 24 is not in contact with the inner periphery of the outer cylinder 12, both the working example and the comparative example have linear characteristics with a relatively small spring constant, and the liquid sealed in the internal space 18 Vibration transmission is appropriately attenuated by the resonance action of. On the other hand, in the contact region R2 in a state where the stopper rubber 24 is in contact with the inner periphery of the outer cylinder 12, the slope of the load-deflection characteristic is larger than in the non-contact region R1, and the spring constant is sharply increased. .
[0024]
Here, in this embodiment, since the surface of the stopper rubber 24 is coated with silicon grease, the hysteresis width D in the load-deflection characteristic is appropriately reduced as compared with the comparative example. That is, the friction at the time of contact is suppressed, and the dynamic spring constant is effectively reduced. As a result, it is possible to suppress the occurrence of a tapping sound and an abnormal sound due to the contact between the stopper rubber 24 and the outer cylinder 12.
[0025]
Further, as shown in FIG. 4, since the uneven portion 28 is formed at the tip of the stopper rubber 24, the surface area of the stopper rubber 24 to which silicon grease is applied substantially increases. As a result, it is possible to more reliably obtain the above-described effects and to suppress the deterioration of the lubricating layer with time.
[0026]
Further, since the uneven portion 28 is formed in a streak shape extending in the axial direction, the axial deformation of the stopper rubber 24 can be effectively suppressed, and compared with the case where the uneven portion is formed along the circumferential direction. As a result, the durability of the stopper rubber 24 is improved, and the performance in the initial stage can be maintained for a long time.
[0027]
FIG. 5 shows an uneven portion of the second reference example, and FIG. 6 shows an uneven portion of the present embodiment . In addition, other configurations are the same, and redundant description will be omitted. In the second reference example shown in FIG. 5, a large number of hemispherically concave and convex portions 30 are formed on the surface of the stopper rubber 24. Uneven portion 32 of the present embodiment shown in FIG. 6 is a number formed on the surface of the stopper rubber 24, the uneven portion 32, around the columnar protrusion 32a, the recess 32b recessed annularly formed ing. In particular, when the uneven portion 32 shown in FIG. 6 is applied, the surface area of the stopper rubber 24 to which the lubricant is applied substantially increases, and the lubricant can be appropriately held in the uneven portion 32 , so that the lubrication can be performed more reliably. The agent can be maintained on the surface of the stopper rubber 24 for a long time.
[0028]
The present invention is not limited to the above-described embodiment, and various modifications and changes can be made without departing from the gist of the present invention.
[Brief description of the drawings]
Sectional view of a liquid-filled vibration damping device according to an embodiment of the present invention; FIG.
FIG. 2 is a sectional view taken along the line AA in FIG. 1;
FIG. 3 is a graph showing load-deflection characteristics of the present embodiment and a comparative example.
4A and 4B show an uneven portion of a stopper rubber according to a first reference example, wherein FIG. 4A is a view corresponding to an arrow B in FIG. 1, and FIG.
5A and 5B show an uneven portion of a stopper rubber according to a second reference example, wherein FIG. 5A is a view corresponding to an arrow B in FIG. 1, and FIG.
6A and 6B show an uneven portion of a stopper rubber according to an embodiment of the present invention, wherein FIG. 6A is a view corresponding to an arrow B in FIG. 1, and FIG.
FIG. 7 is a cross-sectional view showing a liquid-filled type vibration damping device according to a conventional example.

Claims (1)

An inner cylinder and an outer cylinder coaxially arranged, a connecting portion for elastically connecting the inner and outer cylinders, and a diameter from an outer periphery of the inner cylinder so as to restrict relative movement of the inner and outer cylinders to a predetermined range. A liquid-filled vibration isolator having a stopper protruding in the direction, and a stopper rubber coated on the tip of the stopper, wherein liquid is sealed in a space formed between the inner and outer cylinders.
A large number of concave and convex portions are formed on the surface of the stopper rubber that comes into contact with the inner periphery of the outer cylinder when vibrating , and each concave and convex portion has a cylindrical convex portion and an annular concave portion formed around the convex portion. Wherein a lubricant is previously attached to the surface of the stopper rubber .

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