JP6851929B2 - Dynamic damper - Google Patents

Description

The present invention relates to a dynamic damper according to an anti-vibration technique.

Generally, as shown in FIGS. 5A and 5B, the dynamic damper 51 has a structure in which a damper mass 54 is connected to the inner peripheral side of the outer pipe 52 via a plurality of rubber feet 53 on the circumference, and this structure is used. Therefore, it has its own natural frequency in the axial direction, the direction perpendicular to the axis, the twisting direction, and the prying direction.

The dynamic damper 51 is mounted in the hollow propeller shaft 61 used for transmitting the driving force of the automobile, suppresses the vibration of the propeller shaft 61, improves the quietness during running, and reduces the strength due to the resonance of the propeller shaft 61 itself. It is for suppressing.

Japanese Unexamined Patent Publication No. 2004-150543

By the way, as the vehicle weight is reduced in recent years, the natural frequency in the direction perpendicular to the axis (diameter direction) required for the dynamic damper 51 is decreasing. As the natural frequency decreases in the direction perpendicular to the axis, the damper mass 54 may be significantly eccentric at the rotation speed in the normal region, which may lead to rubber breakage. In addition, depending on the vehicle, the input in the normal area is large, which may lead to rubber breakage.

As a conventional measure against eccentricity of the damper mass, as shown in FIG. 6, there is a method in which a convex shape 55 made of a rubber-like elastic body is provided as a stopper on the inner peripheral surface of the outer pipe 52 between the rubber feet 53 adjacent to each other. According to the structure, the amount of eccentricity of the damper mass 54 is regulated by contacting the damper mass 54 with the convex shape 55 when an excessive load is input.

However, in order to regulate the amount of eccentricity of the damper mass 54 to the target value, it is necessary to narrow the clearance c between the damper mass 54 and the convex shape 55, and in that case, there is a problem that a region where the anti-vibration effect can be obtained cannot be sufficiently secured. Occurs.

Further, when the stopper is made of a rubber-like elastic body, the rigidity required for the stopper cannot be secured, and sufficient regulation of the amount of damper mass eccentricity may not be obtained (as shown in the comparative example in the graph of FIG. 3). In addition, even if the stopper is operated by the damper mass 54 coming into contact with the convex shape 55 at the A point, the mass eccentricity tends to increase due to the subsequent compression of the convex shape 55).

In view of the above points, it is an object of the present invention to provide a dynamic damper capable of sufficiently securing a region where an anti-vibration effect can be obtained and sufficiently controlling the amount of eccentricity of the damper mass.

In order to solve the above problems, the dynamic damper of the present invention is a dynamic damper in which damper masses are connected to the inner peripheral side of an outer pipe via a plurality of rubber feet on the circumference, and the amount of eccentricity of the damper masses is reduced to a predetermined amount. A mass stopper portion to be regulated is provided, and the mass stopper portion is characterized by having a structure in which a cloth body is erected between the outer pipe and the damper mass between the rubber feet adjacent to each other.

Further, as an embodiment, in the dynamic damper described above, the cloth body is erected between the outer pipe and the damper mass with a looseness in the length direction thereof.

Further, as an embodiment, in the dynamic damper described above, the cloth body is made of a base cloth.

In the present invention, the mass stopper portion has a structure in which a cloth body is erected between the outer pipe and the damper mass between the rubber feet adjacent to each other. Therefore, when the damper mass is eccentric, the cloth body exerts a high reaction force due to tension. The stopper is activated. The cloth body does not require a large volume and does not require clearance setting unlike the convex shape made of the conventional rubber-like elastic body. Therefore, since the vibration-proof effect is not hindered by the radial displacement of the damper mass, a sufficient area where the vibration-proof effect can be obtained can be secured. In addition, since the cloth stretched to the limit by tension does not stretch any more, the eccentricity amount is surely regulated. Therefore, the amount of eccentricity of the damper mass can be sufficiently regulated.

Front view of the dynamic damper according to the embodiment Front view of the dynamic damper showing the eccentric state of the damper mass Graph diagram showing the results of comparative tests Perspective view of the main part of the mold for manufacturing the dynamic damper It is a figure which shows the dynamic damper which concerns on the background technology, (A) is the front view, (B) is the sectional view cut by the plane including the central axis. It is a figure which shows the dynamic damper which concerns on the comparative example, and is the sectional view cut by the plane in the direction perpendicular to the axis.

As shown in FIG. 1, the dynamic damper 11 according to the embodiment is a shaft insertion type / inner type dynamic damper mounted in a hollow portion of a propeller shaft (not shown) which is a rotating shaft.

The dynamic damper 11 has an outer pipe (outer cylinder) 12 fitted to the inner peripheral surface of the hollow portion of the propeller shaft as a component thereof, and a plurality of outer pipes 12 on the inner peripheral side of the outer pipe 12 (in the figure). The damper mass 14 is concentrically connected via the rubber feet 13 (5 equal parts). The surface of the outer pipe 12 may be covered with a rubber-like elastic body integrated with the rubber feet 13, and the surface of the damper mass 14 may also be covered with a rubber-like elastic body integrally with the rubber feet 13.

Further, a mass stopper portion 21 for restricting the amount of eccentricity of the damper mass 14 to a predetermined amount is provided, and the mass stopper portion 21 is provided between the outer pipe 12 and the damper mass 14 between the rubber feet 13 adjacent to each other on the circumference. The cloth 22 is erected in the direction perpendicular to the axis (diameter direction). The cloth body 22 is arranged in the same number as the rubber feet 13 (5 equal parts in the figure), and is arranged alternately with the rubber feet 13 on the circumference. The gap between the fibers constituting the cloth body 22 may be filled with a rubber-like elastic body integrated with the rubber feet 13, and the surface of the cloth body 22 is covered with the rubber-like elastic body integrated with the rubber feet 13. You may have.

Further, the cloth body 22 is erected between the outer pipe 12 and the damper mass 14 with a looseness in the length direction thereof. The looseness is set by making the erection length of the cloth 22 larger than the distance between the outer pipe 12 and the damper mass 14. By setting the looseness, the cloth 22 is often wavy or meandering in the erected state. The cloth body 22 is, for example, a base cloth.

In the dynamic damper 11 having the above configuration, the mass stopper portion 21 has a structure in which the outer pipe 12 and the cloth body 22 are erected between the rubber feet 13 adjacent to each other on the circumference, and therefore, as shown in FIG. When the damper mass 14 is eccentric, the cloth body 22 arranged near the position 180 degrees symmetrical with the eccentric direction (arrow B) is pulled by the damper mass 14, the looseness disappears, and when the cloth body 22 is stretched to the limit. Demonstrate high reaction force. Therefore, the mass stopper portion 21 operates as a stopper, and the amount of eccentricity of the damper mass 14 can be suppressed to a predetermined amount.

In other words, the present invention suppresses the eccentricity of the damper mass 14 when the propeller shaft rotates at high speed, and secures durability against resonance in the direction perpendicular to the axis. From this point of view, in the present invention, when the damper mass 14 is eccentric during high-speed rotation of the propeller shaft, the cloth body 22 operates as a stopper for a high reaction force, so that the eccentricity of the damper mass 14 can be suppressed.

Further, the cloth body 22 does not require a large volume unlike the convex shape 55 made of the conventional rubber-like elastic body, and does not require the setting of the clearance c. Therefore, since the damping effect is not hindered by the radial displacement of the damper mass 14, it is possible to secure a sufficiently wide region where the vibration damping effect can be obtained.

Further, since the length of the cloth 22 stretched to the limit does not increase any more, the amount of eccentricity is surely regulated. Therefore, the eccentricity amount of the damper mass 14 can be sufficiently regulated.

As shown in the graph of FIG. 3, in the comparative example of FIG. 6, as described above, even if the stopper is operated by the damper mass 54 coming into contact with the convex shape 55 at the A point, the convex shape 55 is subsequently compressed. In contrast to the above-described embodiment, when the cloth 22 is stretched to the limit at the D point and the stopper is operated, the mass eccentricity increases thereafter. do not do. Therefore, the eccentricity amount of the damper mass 14 can be sufficiently regulated.

Further, as can be seen from the difference in the positions of the A and D points, according to the embodiment, the timing of starting the stopper operation can be brought closer to the target eccentricity amount, and the timing of starting the stopper operation can be delayed (stopper operation). Because there is no need to consider further eccentricity later).

Further, by using the cloth 22 having a small amount of deformation with respect to the load, it is possible to regulate the displacement with a low displacement amount when an excessive load input occurs as compared with the conventional stopper. Therefore, it is possible to realize the regulation to the target displacement amount.

Further, by utilizing the elastic force of the rubber-like elastic body in addition to the tension of the cloth body 22, it is possible to regulate with a further low displacement when an excessive load is input.

Next, the method for manufacturing the dynamic damper 11 will be described. In the manufacturing of the dynamic damper 11, insert molding is performed using a rubber molding die.

As a part of the mold, the upper mold and the lower mold (lower mold in the figure) 31 shown in FIG. 4 are used. The upper mold and the lower mold 31 have a tubular portion 32, and the outer pipe 12 is set on the outer peripheral side of the tubular portion 32, and the damper mass 14 is set on the inner peripheral side of the tubular portion 32. Since the tubular portion 32 is provided with a plurality of notches 33 on the circumference (5 equal parts in the figure), the rubber feet 13 are formed by the rubber material injected and filled in the notches 33. Further, since the tubular portion 32 is provided with a plurality of notches 33 and a plurality of narrow and wavy notches 34 (5 equal parts in the figure) alternately on the circumference, the cloth body 22 is provided in the notches 34. The cloth body 22 is connected to the outer pipe 12 and the damper mass 14 by the rubber material that is set and injected / filled into the notch 34. Therefore, according to this manufacturing method, it is possible to simultaneously mold the rubber feet 13 and connect the cloth 22 by one vulcanization molding.

11 Dynamic damper 12 Outer pipe 13 Rubber feet 14 Damper mass 21 Mass stopper part 22 Cloth body 31 Upper type and lower type (split type)
32 Cylindrical part 33 Notch (Notch for rubber foot molding)
34 Notch (Notch for integrating cloth)

Claims (3)

In a dynamic damper in which damper mass is connected to the inner circumference side of the outer pipe via multiple rubber feet on the circumference.
A mass stopper portion is provided to regulate the amount of eccentricity of the damper mass to a predetermined amount.
The mass stopper portion is a dynamic damper having a structure in which a cloth body is erected between the outer pipe and the damper mass between the rubber feet adjacent to each other. In the dynamic damper according to claim 1,
A dynamic damper characterized in that the cloth body is erected between the outer pipe and the damper mass with a looseness in the length direction thereof. In the dynamic damper according to claim 1 or 2.
The cloth body is a dynamic damper characterized by being made of a base cloth.

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