JPH0788870B2 - Liquid-sealed elastic bush - Google Patents

Description

TECHNICAL FIELD The present invention relates to a liquid-sealed elastic bush suitable for use in a so-called roll insulator or the like, which regulates rolling of an engine or the like mounted on an automobile. is there.

(B) Conventional technology Conventionally, in order to achieve the initial performance of the roll insulator as described above, it was usual to use an oil type damper in which a bush type vibration-proof rubber and a hydraulic cylinder are used together. . However, if these combined types are used, the size of the device becomes large, the space is increased, and the cost becomes high.

On the other hand, conventionally, with a particular emphasis on damping performance, a so-called liquid-sealing elastic bush is known, which defines a liquid-sealing liquid chamber communicating with an orifice in a rubber elastic body having a cylindrical and compact shape. As a result (Japanese Patent No. 738523, Japanese Patent No. 885820, etc.), attempts have been made to use it in such a place.

(C) Problems to be solved by the invention However, such a liquid-sealed elastic bush still fails to obtain a sufficient effect. The reason is that the rubber elastic body itself must have a certain degree of hardness (spring constant) in order to support the load due to vibration, etc. Then, when a sudden external force acts, this time This is because there is not enough liquid transfer to exert the damping function.

(D) Means for Solving the Problems Therefore, according to the present invention, a rubber elastic body composed of a partition wall and a side wall is molded between an outer cylinder and an inner cylinder arranged concentrically to form two liquid chambers. In a liquid-sealing type elastic bush that is separated from each other and communicates between these liquid chambers by an orifice passage, a ring with a groove communicating with both liquid chambers is fitted to the outer periphery of the inner cylinder to form the orifice passages. A liquid-sealing elastic bush characterized in that both side walls of the inner cylinder of the liquid chamber are bent inward, and stoppers made of a rubber elastic body that extend from the outer cylinder toward the inner cylinder are provided in both liquid chambers. By solving the above problem, the above-mentioned problems are solved.

(E) Action With this configuration, when an external force is applied and this elastic bush is about to be displaced (at this time, one liquid chamber contracts and its volume decreases, and the other liquid chamber expands). The volume of the liquid chamber must be increased) and the side walls of the liquid chamber are curved, so that the pump action described below is exerted, and the contraction and expansion thereof are promoted. That is,
When one of the liquid chambers tries to contract, the side wall on this side contracts due to internal stress or the like to easily imitate the curvature, and the side wall on the other side shrinks much more than a straight side wall. Reduces bending with a small force and extends. Therefore, these two actions synergistically increase the amount of the liquid moving between the two liquid chambers, thereby exhibiting a high damping function. Furthermore, the curved side wall also contributes to the increase in the liquid transfer amount for another reason. In other words, the volume change due to the contraction and expansion of the liquid chamber whose side wall is curved is large compared to the volume change of a straight side wall due to the large surface area.
Even with the same displacement, the amount of liquid movement increases. Moreover, by adopting such a configuration, a low spring constant required at the time of minute vibration can be secured. That is, the resistance to contraction and expansion of the liquid chamber is small, and therefore it can be said that it is so soft. In addition, a grooved ring is fitted to the inner cylinder to secure the orifice passage, compared to the case where the passage is directly formed in the partition wall or formed along the inner circumference of the outer cylinder. Has a merit that the structure is simple and the strength of other members is not reduced. Also, by providing a stopper inside the liquid chamber, a simple and compact structure is achieved.

(F) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1 and 2 are sectional views taken along line I-I and sectional view taken along line II-II of FIG. 3, FIG. 3 is a front view of a liquid-sealed elastic bush, and FIG. 4 is a sectional view taken along line IV-IV of FIG. FIG. 5 is a longitudinal sectional view showing the relationship between the elastic bush and the outer cylinder, and FIGS. 6 and 7 are graphs showing the relationship between the damping coefficient and the frequency and the vibration transfer coefficient and the frequency.

As shown in FIG. 1 and the like, this liquid-sealing type elastic bush has an inner cylinder 2 and an outer cylinder 1 each made of a metal material or the like.
Are arranged in parallel and concentrically, a rubber elastic body 3 is molded between the outer cylinder 1 and the inner cylinder 2 to separate a plurality of liquid chambers 4, and an orifice is provided between these liquid chambers 4. The communication is made through the passage 5. That is, in the axial direction of the outer cylinder 1, the partition wall 3a of the rubber elastic body 3 is provided between the outer cylinder 1 and the inner cylinder 2 in a substantially horizontal wing shape (see FIG. 4). A side wall 3b is stretched in a direction perpendicular to and with a constant interval (see FIG. 1), and the liquid chamber 4 is vertically separated by these both members. A predetermined liquid 6 is placed inside these liquid chambers 4.
The liquid is sealed by the method described below. Regarding the above-mentioned formation of the orifice passage 5, the ring 7 having the groove 5a formed on the outer periphery is fitted onto the inner cylinder, and the sleeve 8 is formed on the outer periphery of the ring 7.
Is fitted and the lid is covered, and an opening hole 5b is provided in a portion of the sleeve 8 inside the both liquid chambers 4 (see FIG. 4 and the like). As a result, the liquid 6 in both liquid chambers 4 can freely move through the orifice passage 5 including the opening 5b and the groove 5b.

Near the outer peripheral end of the rubber elastic body 3, a sleeve-shaped core metal 9 is sealed, in which a portion where the liquid chamber 4 is located is cut out like a window 9a (see FIGS. 1 and 4). It should be noted that the core metal 9 is sealed in this way so that the strength of the rubber elastic body 3 itself is maintained and the rubber elastic body 3 is not compressed strongly but the inner cylinder is
2, because it is interposed between the outer cylinder 1. Therefore, the rubber elastic body 3 itself has a low spring constant, and is excellent in vibration absorption during minute vibrations. Further, the outermost periphery of the rubber elastic body 3 is also slightly piled up on the outer periphery side of the vibrating plate 9, and a plurality of (about 2 to 5) ridges 10 are formed all around the periphery. Therefore (see FIG. 5), when it is fitted into the outer cylinder 1, its water tightness is improved.

The method of enclosing the liquid 6 in the liquid chamber 4 is as follows. By providing the core metal 9 and the ridge 10 as described above, the inner cylinder 2 is molded with the rubber elastic body 3 as described above. The liquid 6 can be easily sealed in the liquid chamber 4 by immersing it in the outer cylinder 1 and immersing the liquid 6 therein. At this time, in the liquid chamber 4, a stopper 11 made of a rubber elastic body that regulates the large displacement of the inner cylinder 2 is generated.
Is provided so as to extend from the outer cylinder 1 to the inner cylinder 2 side (see FIG. 4).

As described above, when the outer cylinder 1 side is attached to the fixing member and the supported member (vibrating member) is fixed to the inner cylinder 2, the supported member can be elastically supported. At this time, the amount of movement of the liquid 6 between the liquid chambers 4 is due to both the above-described pumping action due to the curved side wall 3a of the liquid chamber 4 and the large volume change due to this unique shape. It increases and exhibits high damping. FIG. 6 is a graph showing the relationship between the loss factor tan δ (attenuation coefficient) and the frequency of the curved side wall 3a (referred to as an invention product) and the straight one (referred to as a conventional product). ， Invention product and conventional product
This means that a difference of several to several tens of times was found in the value of tan δ. FIG. 7 shows the storage spring constants of the invention product and the conventional product.
It is a graph showing the relationship between Kd (vibration transfer coefficient) and frequency. In this case, it was confirmed that the vibration transfer coefficient is low in the relatively low frequency range that is generally used. This is because by doing so, the softness of the spring can be maintained as described above.

By the way, in the above embodiment, the outer cylinder 1 and the inner cylinder 2 are arranged concentrically, but this has a zero load in the normal state (non-vibration), and a positive and negative This is because they are used in places where the amplitudes are equal.

(G) Effect of the Invention As described above, the present invention is as described above, that is,
In the liquid-sealing type elastic bush as described above, since both side walls 3b of each liquid chamber 4 are bent inward, movement of the liquid 6 between the liquid chambers 4 during a relatively large vibration is prevented. It promotes and exhibits a high damping function. Further, the fact that the liquid 6 can be easily moved between the liquid chambers 4 means that the liquid 6 is so soft and the spring constant is low. Further, the orifice passage 5 is grooved.
With the structure in which the ring 7 having the 5a is fitted to the inner cylinder 2 and the structure in which the stopper 11 is provided in the liquid chamber 4 and protrudes from the outer cylinder 1 to the inner cylinder 2 side, the structure is simple. It was possible to realize a highly durable product in a compact form.

[Brief description of drawings]

1 and 2 are sectional views taken along line I-I and sectional view taken along line II-II of FIG. 3, FIG. 3 is a front view of a liquid-sealed elastic bush, and FIG. 4 is a sectional view taken along line IV-IV of FIG. FIG. 5 is a longitudinal sectional view showing the relationship between the elastic bush and the outer cylinder, and FIGS. 6 and 7 are graphs showing the relationship between the damping coefficient and the frequency and the vibration transfer coefficient and the frequency. (Code) 1 …… Outer cylinder 2 …… Inner cylinder 3 …… Rubber elastic body 3a …… 〃 partition wall 3b …… 〃 side wall 4 …… Liquid chamber 5 …… Orifice 5a …… Groove 6 …… Liquid 7 ... … Ring 11 …… Stopper

Claims (1)

[Claims] 1. An outer cylinder (1) and an inner cylinder (2) arranged concentrically.
A rubber elastic body (3) consisting of a partition wall (3a) and a side wall (3b) is molded between the two liquid chambers (4) to separate them, and an orifice passage (5) is provided between these liquid chambers (4). ), A ring (7) having a groove (5a) communicating with both liquid chambers (4) is fitted around the outer periphery of the inner cylinder (2) to form an orifice passage (5). On the other hand, both side walls (3b) of the inner cylinder (2) of each liquid chamber (4) are bent inwardly, and the outer cylinder (1) to the inner cylinder (2) are inserted into both liquid chambers (4). ) Side of the rubber elastic body (3) stopper (1
A liquid-sealed elastic bush characterized by having 1).