JPH02266137A - Viscous fluid sealed type dynamic damper - Google Patents

Abstract

PURPOSE:To perform an optimum design for a damper mechanism easily by forming a void in space between a mounting member for a damping member and a mass member, sealing a high viscous fluid in this void, while installing a projection jutting out into the void from the mass member, and forming a slit constrictive part in a projection end. CONSTITUTION:A rubber elastic body 14 constituting a molding 20 is formed with a recess 22 in the inner part, and opened at an edge of a hold fitting 24. A mass fitting 24 assembled so as to close this opening is formed with a working projection 28 of a circular block at the central part, and a high viscous fluid is liquiditightly sealed in the recess 22. When a mounting bracket 10 is tightly contacted with a damping object by a mounting bolt 12, a mass fitting 24 is set down to a mass body, and elasticity of the rubber elastic body 14 and the high viscous fluid is used for a spring component, thus a damping effect is brought into full play. A constrictive part 40 is installed on a projection end 36 of the working projection 28, and this size is adjusted whereby damping force by slippage shearing force of the high viscous fluid is easily possible for tuning.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a viscous fluid, in which the damping rate of a damper can be set sufficiently large, thereby making it possible to easily and advantageously design an optimal design by tuning to the optimal damping. This invention relates to an enclosed dynamic damper.

(Background technology) Conventionally, as a type of damper mechanism for suppressing the vibration of various mechanical structures such as automobile engine units and exhaust pipes, rubber elastic A dynamic vibration absorber having a structure in which mass members of a predetermined mass are elastically connected through the body,
A so-called dynamic damper is known.

By the way, in order to effectively obtain the damping effect of such a dynamic damper, it is important to tune the mass mass, spring constant, and damping coefficient in the sub-vibration system consisting of the rubber elastic body and the mass member. As is well known, their tuning is generally performed according to the fixed point theory in the optimal design method for dynamic dampers.

More specifically, in a mechanical model, a mechanical structure to be damped equipped with such a dynamic damper has itself as a main vibration system and the dynamic damper as a secondary vibration system.
When expressed as a degree-of-freedom system, the vibration magnification curve takes maximum values at two resonance frequency points, but regardless of the damping rate of the sub-vibration system, such a vibration magnification curve always
Since the curve passes through two fixed points, by making the values of the two fixed points equal and having the maximum value of the amplitude magnification curve near these fixed points, the resonance peak in the main vibration system can be minimized. This means that it can be suppressed. Therefore, when tuning such a dynamic damper, first set the mass and spring constant of the sub-vibration system so that the heights of the two fixed points are equal (optimal tuning), and then This is done by setting the damping coefficient of the sub-oscillation system (optimal damping) so that the maximum value of the amplitude magnification is achieved in the vicinity.

However, in the dynamic damper of the conventional structure as described above, the spring constant and damping coefficient of the sub-vibration system are both set by the elasticity and damping of the rubber elastic body, so it is difficult to obtain sufficient damping. Therefore, it is difficult to set a damping coefficient that provides optimal damping while ensuring a spring constant that provides optimal tuning.
This has the inherent problem that it may not be possible to obtain an effective vibration suppression effect.

In addition, in such a dynamic damper, since the temperature dependence of the damping coefficient in the rubber elastic body is relatively large, it is difficult to achieve the desired result, especially when it is installed in a member that gets hot, such as an automobile engine unit. It also had the disadvantage that it was difficult to fully exhibit the vibration suppressing effect, and a stable effect could not be expected.

(Problem to be solved) Here, the present invention has been made against the background of the above-mentioned circumstances, and the problem to be solved is:
The damping rate of the secondary vibration system can be set sufficiently large,
The object of the present invention is to provide a viscous fluid-filled dynamic damper in which the damper mechanism can be easily and advantageously designed optimally by tuning to optimal tuning and damping.

(Solution Means) In order to solve this problem, in the present invention, a mass member is arranged facing a mounting member attached to a predetermined vibration damping target at a predetermined distance, and In a dynamic damper in which a member and a mass member are elastically connected by a rubber elastic body interposed between them, a peripheral wall is provided between the mounting member and the mass member by the rubber elastic body. A high viscosity fluid having a high kinematic viscosity is sealed in the cavity, and at least one of the mounting member side and the mass member side protrudes into the cavity. The feature is that a working convex part is provided, and a narrow narrow part is formed on the protruding end surface of the working convex part, expanding in a direction perpendicular to the direction in which the mounting member and the mass member face each other. It is.

(Examples) Hereinafter, in order to clarify the present invention more specifically, examples of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 shows an embodiment of a dynamic damper having a structure according to the present invention.

In this figure, reference numeral 10 denotes a mounting metal fitting formed in the shape of a disk, and integrally provided with a mounting bolt 12 projecting to one side in the axial direction at the center thereof.

As shown in FIG. 2, this mounting bracket 10 has a rubber elastic body 14 in the shape of a thick disk on the side opposite to the side from which the mounting bolt 12 is protruded. ,
It is integrally vulcanized and bonded on one end surface in the axial direction, and furthermore, the other end surface in the axial direction of this rubber elastic body 14 has a circular plate shape with a caulked portion 16 on the outer peripheral edge. The holding fittings 18 are integrally vulcanized and bonded. That is, the rubber elastic body 14 is attached to the mounting bracket 10.
It is formed as an integrally vulcanized molded crystal 20 having the holding fittings 18 integrally on both sides in the axial direction.

Further, the rubber elastic body 14 constituting the integrally vulcanized molded product 20 has a circular recess 22 formed therein, and is opened at the end face on the holding fitting 18 side. Then, the mass fitting 2 is attached to the integrally vulcanized product 20 so as to close the opening of the recess 22.
4 has been assembled.

Therefore, the mass fitting 24 has a structure in which a circular block-shaped working convex part 28 is integrally formed on the central part of the disk-shaped plate part 26 on the negative side thereof. has been done.

As shown in FIG. 1, this mass fitting 24 is superimposed on the holding fitting 18 of the integrally vulcanized molded product 20 at the outer peripheral edge of the plate-like part 26, and furthermore, the outer peripheral edge By caulking and fixing the caulking part 16 to the part, the working convex part 28 is integrally assembled with the part protruding into the recess 22, and thereby, the mass fitting 24 is , are positioned opposite to the mounting bracket 10 at a predetermined distance, and
They are integrally and elastically connected by a rubber elastic body 14 interposed between them.

Then, by assembling the mass fitting 24, the opening of the recess 22 is closed, and a predetermined high viscosity fluid is sealed in the recess 22.
A fluid chamber 32 is formed within the recess 22 . Note that two annular seal lips 3 are provided on the surface of the holding fitting 18 on which the plate-like portion 26 of the mass fitting 24 is superimposed.
A sealing rubber layer 34 having a diameter of 0 is integrally formed with the rubber elastic body 14, thereby ensuring fluid tightness of the fluid chamber 32 between the caulked portions.

In addition, such a high viscosity fluid has a kinematic viscosity of at least 10,000 centistokes or more, preferably 100,000 to 1,000,000 centistokes, and has a wide range, in order to effectively obtain the shear stress described below. A material whose viscosity changes little over a temperature range is preferably used, and silicone oil is usually used.

Further, it is also possible to seal such a highly viscous fluid into the fluid chamber 32 by assembling the mass fitting 24 to the integrally vulcanized product 20 in the fluid; Since it is troublesome to remove the fluid attached to the surface, for example, it is difficult to remove the fluid attached to the surface.
4, by injecting a predetermined amount of fluid into the recess 22 of the integrally vulcanized molded product 20 in advance, or after the mass fitting 24 is assembled to the integrally vulcanized molded product 20,
It is preferable to fill the fluid through an injection hole formed in the mass fitting 24, and then close the injection hole with a rivet or the like after the filling.

Furthermore, the operating convex portion 28 of the mass fitting 24, which is positioned so as to protrude into the fluid chamber 32 formed in the recess 22, is formed with a size smaller than the recess 22. As a result, a fluid presence region is formed around the working protrusion 28, and in particular, between the protruding end surface 36 of the working protrusion 28 and the bottom surface 38 of the recess 22, the mass fitting 24 and A narrow narrow portion 40 is formed which is a narrow gap that widens in a direction perpendicular to the direction facing the mounting bracket 10.

In the dynamic damper having such a structure, the mounting fitting 10 is fixed to a predetermined vibration damping target by the mounting port 2, thereby making the mass fitting 24 a mass body, It functions as a sub-vibration system whose spring components are the elasticity of the rubber elastic body 14 and the enclosed fluid, and thus, similar to conventional dynamic dampers, the vibration phenomenon of the sub-vibration system provides vibration absorption to the damping target (main vibration system). The effect will be demonstrated.

In particular, in the dynamic damper having the above-described structure, when vibration is generated by human vibration vibration from the vibration damping target, the displacement of the mass fitting 24 and the deformation of the rubber elastic body 14 cause the fluid to flow. A flow is induced in the highly viscous fluid sealed in the chamber 32,
Therefore, this flow can exert a damping effect based on the shear stress of the viscous fluid.

Specifically, for example, when vibration in the direction in which the mounting bracket 10 and the mass bracket 24 face each other (direction P in FIG. 1) is input to such a dynamic damper, the protruding end surface 36 of the working convex portion 28 In the narrowed part 40 formed between the narrowed part 40 and the bottom surface 38 of the recess 22, a pressing force acts on the high viscosity fluid existing there, and the high viscous fluid is expelled from the narrowed part 40 to the outside (peripheral part). As a result of the action of A damping force can be exerted.

Alternatively, when vibration in a direction perpendicular to the direction in which the mounting fitting 10 and the mass fitting 24 face each other is input to such a dynamic damper (in the Q direction during the first H),
By displacing the working convex portion 28 relative to the inner surface of the recess 22, a flow is induced in the highly viscous fluid sealed within the constriction portion 40, based on the shear shear stress generated thereby. Therefore, a high damping force can be exerted.

By the way, setting of the spring constant and damping coefficient in such a dynamic damper is not only done by tuning the characteristics of the rubber elastic body, but also by adjusting the area that receives the shear stress of the high viscosity fluid, that is, the protrusion of the working convex part 28. End face 3
The size of 6; the gap between φD and the narrowing portion 40;! These can also be effectively achieved by adjusting the size of the protruding end surface: φD, or by decreasing the gap l of the narrowed part 40. The spring constant and damping coefficient can be increased.

In addition, there, the gap: l of the narrowing part 40 is
If it is too large, shear stress cannot be effectively generated, so it is generally 15, although it depends on the viscosity of the enclosed fluid.
It is desirable to set it to less than mm, preferably less than 51nff1.

Therefore, in the dynamic damper having the above structure, the damping force can be exerted not only by the rubber elastic body 14 but also by the shear stress of the highly viscous fluid, and the magnitude of the damping force is can be tuned by adjusting the size and gap amount of the narrowed portion 40, so a large damping coefficient can be easily set with good tunability.

Therefore, when tuning such a dynamic damper, it is possible to advantageously achieve both optimal tuning and optimal damping. Therefore, a dynamic damper that can extremely effectively suppress this can be advantageously provided.

Furthermore, in such a dynamic damper, by employing silicone oil as the sealed fluid, temperature changes in the damping coefficient can be effectively prevented or suppressed, thereby preventing the engine unit from becoming too hot. Even when the device is attached to a member that is attached to the device, the desired vibration suppressing effect can be stably exhibited.

In addition, in the dynamic damper of this embodiment, the working convex portion 28 that projects into the fluid chamber 32 and forms the constriction portion 40 is configured as a mass body in the damper by the mass fitting 24, so that it is compact. It also has the advantage that it can be advantageously achieved.

Furthermore, in the dynamic damper of this embodiment, since the bottom surface 38 of the recess 22 facing the protruding end surface 36 of the working convex portion 28 is formed of the rubber elastic body 14, an excessively large amount of The impact when the working protrusion 28 comes into contact with the bottom surface 38 during vibration input can be advantageously alleviated.

Although the embodiments of the present invention have been described in detail above, these are literal illustrations, and the present invention is not to be construed as being limited only to these specific examples.

For example, the shape of the mass fitting 24 is not limited, and should be changed as appropriate to adjust the mass mass during tuning. It is possible to reduce the weight by adding the additional mass part 42 to the outer surface of the part 26 or by making the working convex part 28 hollow.

Further, the working convex portion 28 may be formed of a rubber elastic body or the like.

Furthermore, it is also possible to form the working protrusion (28) so as to protrude from the mounting fitting 10 side, or to protrude from both the mounting fitting 10 side and the mass fitting 24 side.

Furthermore, the shapes of the fluid chamber 32 and the working convex portion 28 are not limited to the circular block shape as illustrated, but shapes such as a rectangular block shape can also be adopted as appropriate.

Furthermore, in the above embodiment, the rubber elastic body 14 was integrally vulcanized and bonded to the mounting bracket 10 side, but as shown in FIG. It is also possible to integrally vulcanize and bond. In addition, such fourth
In the drawings, in order to facilitate understanding, the same reference numerals are given to members having the same structure as in the above embodiment.

In addition, although not listed, the present invention can be implemented in embodiments with various changes, modifications, improvements, etc., based on the knowledge of those skilled in the art, and such embodiments are not limited to the present invention. It goes without saying that any of these are included within the scope of the present invention as long as they do not depart from the spirit of the invention.

(Effects of the Invention) As is clear from the above description, in the viscous fluid-filled dynamic damper according to the present invention, the damping force is generated not only by the rubber elastic body but also by the shear of the highly viscous fluid sealed inside. The damping force due to the shear stress of this highly viscous fluid can be easily tuned by adjusting the size of the constriction formed in the fluid chamber, and can be easily tuned to a sufficiently large damping force. It can be set to a value.

Therefore, according to the present invention, the optimum design of the damper mechanism can be easily and effectively achieved by tuning to optimum synchronization and optimum damping. A damper can advantageously be provided.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an example of an integrated dynamic damper according to the present invention, and FIG. 2 is an explanatory diagram of the assembly of such a dynamic damper. Moreover, FIGS. 3 and 4 are longitudinal cross-sectional views showing other specific examples of the dynamic damper according to the present invention. 10: Mounting bracket 14: Rubber elastic body 22: Recess
24: Mass metal fitting 28; Working convex portion 32
:Fluid chamber 36:Protruding end surface 38:Bottom surface 40;Constricted portion Applicant: Tokai Rubber Industries Co., Ltd. No. 3 C! @Figure 4

Claims (1)

[Claims] A mass member is disposed facing a mounting member attached to a predetermined vibration damping target at a predetermined distance, and the mounting member and the mass member are interposed between them. A dynamic damper that is elastically connected using a rubber elastic body, wherein a space is formed between the mounting member and the mass member, the peripheral wall portion of which is made of the rubber elastic body; A highly viscous fluid with high kinematic viscosity is sealed in the cavity, and from at least one of the mounting member side and the mass member side,
A working protrusion protruding into such a space is provided, and a slender narrowing part is formed on the protruding end surface of the working protrusion, expanding in a direction perpendicular to the direction in which the mounting member and the mass member face each other. A dynamic damper filled with viscous fluid.