JPH08177975A - Dynamic damper - Google Patents

Abstract

PURPOSE: To provide a dynamic damper capable of regulating over a wide range a ratio of the spring constant in the direction orthogonal to the axis of a rotary shaft to that in the axial direction without substantially changing the dimension of an elastic member. CONSTITUTION: A cylindrical mass member 2 and an elastic member 3 for connecting the mass member 2 to a rotary shaft S are provided so that the elastic member 3 is connected on the inner surface of the mass member 2 to the nearly intermediate part of the mass member in the longitudinal direction, while a pair of annular walls 3a, 3b extend from the connection part to the respective ends of the mass member 2 and incline to approach gradually the axis of the mass member 2 as they extend to the ends. In the tips of these annular flanges 3a, 3b, the elastic member 3 is adapted to be connected to the rotary shaft S.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic damper mounted on a rotary shaft such as a drive shaft or a propeller shaft of a vehicle so as to suppress vibrations generated on these rotary shafts.

[0002]

2. Description of the Related Art Generally, it is known that vibrations due to unbalanced mass, vibrations such as bending vibrations and torsional vibrations are generated on a rotating shaft such as a drive shaft or a propeller shaft of a vehicle. Has been.

Especially, in a front-wheel drive vehicle, since the drive shaft is connected to the front wheels to which the steering mechanism is connected, the vibration generated in the drive shaft is transmitted to the driver via the steering mechanism. Easy to be transmitted to.

In order to solve such a problem, in the conventional example, a dynamic damper is attached to the rotary shaft,
The vibration is suppressed by absorbing the vibration energy generated in the rotating shaft.

This dynamic damper includes a fixing member fitted to the rotary shaft, a mass member arranged so as to surround the fixing member, and an elastic member connecting the fixing member and the mass member. The elastic member is arranged along a direction orthogonal to the axis of the rotating shaft, and the rotating shaft and the mass member are relatively opposed to each other by resonance with vibration in a direction orthogonal to the axis of the rotating shaft. While being moved, the elastic member is elastically deformed, and by utilizing the elastic deformation of the elastic member, the vibration energy of the rotating shaft is absorbed,
Vibration of the rotating shaft is suppressed.

In order to resonate the rotary shaft and the dynamic damper, it is necessary to match the natural frequency of the dynamic damper with the target vibration frequency of the rotary shaft. Is determined by the mass of the mass member and the spring constant of the elastic member. Therefore, in the past, the natural frequency of the dynamic damper was changed mainly by changing the shape of the elastic member to adjust the spring constant. It is set.

[0007]

In the conventional dynamic damper described above, the damping direction is
Although only the direction orthogonal to the rotation axis is targeted, in reality, there are cases in which vibration in the axial direction of the rotation axis cannot be ignored.

However, in the above-mentioned conventional dynamic damper, the following problems occur when it is attempted to suppress the vibration in the axial direction of the rotary shaft.

That is, when the elastic member is arranged along the direction orthogonal to the rotation axis as in the conventional dynamic damper, when the elastic member is deformed (compression / tensile deformation) in the direction orthogonal to the axis of the rotation shaft. The relationship between the elastic modulus (α) and the elastic modulus (β) at the time of axial deformation (shear deformation) is expressed by the following equation 1.

Α / β = (3 + 6.58S ² ) · (1 + 1 / 48S ² ) ... 1 Formula Here, S is represented by the ratio of the constrained area (pressure receiving area) of the elastic member and the free surface area. Is the value

As is clear from this equation, the ratio of the elastic modulus in the compression / pulling direction and the elastic modulus in the shearing direction of the elastic member is determined by the shape of the elastic member.

Therefore, in the prior art, when changing or adjusting the elastic modulus ratio, the shape of the elastic member has to be changed. However, in reality, the elasticity is required because of the strength required for the dynamic damper. The shape and dimensions of the members are limited within a certain range, and the adjustment range of the elastic modulus ratio is also limited accordingly, and the spring constants in both directions are set to target values that can be put to practical use. Has become difficult.

The present invention has been made in view of the above-mentioned conventional problems, and the spring constant in the direction orthogonal to the axis of the rotary shaft and the spring in the axial direction are obtained without significantly changing the dimensions of the elastic member. An object of the present invention is to provide a dynamic damper capable of adjusting a ratio with a constant over a wide range.

[0014]

In order to achieve the above-mentioned object, a dynamic damper according to a first aspect of the present invention has a substantially concentric shape around a rotation shaft with a space between the rotation shaft and the rotation shaft. In a dynamic damper provided with a cylindrical mass member disposed in, and an elastic member connecting the mass member and the rotating shaft, the elastic member is an inner surface of the mass member in a longitudinal direction thereof. A pair of annular rings which are connected to a substantially intermediate portion and which are inclined toward the respective end portions of the mass member from the joint portion and gradually toward the respective end portions of the mass member. It is characterized in that it has walls, and the elastic members are connected to the rotary shaft at the tip ends of these annular walls.

According to a second aspect of the present invention, in the dynamic damper according to the first aspect, a flange extending along a plane orthogonal to the axis of the mass member is connected to the outer periphery of the continuous portion of both annular walls of the elastic member. The elastic member and the mass member are connected to each other via the flange.

Further, in the dynamic damper according to a third aspect of the present invention, a fixing member that is fitted to the outer circumference of the rotary shaft is connected to the tip end portion of each of the annular walls according to the first or second aspect. It is characterized by being

[0017]

According to the dynamic damper of the first aspect of the present invention, since each annular wall is inclined with respect to the axis of the mass member, the lengthwise direction (compression / pulling) of each annular wall is reduced. The longitudinal elastic modulus in the direction) and the lateral elastic modulus in the direction orthogonal to the length direction (shear direction) respectively include the axial component and the axially orthogonal component of the mass member.

Therefore, the composite values of these axial components and the components perpendicular to each other are the elastic modulus in the axial direction of the elastic member and the elastic modulus in the direction perpendicular to the axis. The spring constants of the elastic member in the axial direction and the axis-perpendicular direction are determined.

The ratio of the axial component to the axially orthogonal component in the longitudinal elastic modulus and the transverse elastic modulus changes depending on the inclination angle of the annular wall with respect to the axis of the mass member, in other words, the inclination angle is changed. By doing so, it becomes possible to adjust the ratio of these axial direction component and axial orthogonal direction component, and it is also possible to adjust the spring constant ratio of the elastic member in the axial direction and axial orthogonal direction.

Therefore, when adjusting the ratio of the spring constant in the direction perpendicular to the axis of the mass member in the elastic member and the spring constant in the axial direction, the shape change of the elastic member is suppressed to the minimum.

According to the dynamic damper of the second aspect of the present invention, the movement of the mass member elastically deforms both the annular walls and the flange provided at the continuous portion thereof.

Here, since the flange is provided along the direction orthogonal to the axis of the mass member, the spring constant in the direction perpendicular to the axis and the spring constant in the flange and the annular wall The spring constant in each direction of the elastic member is determined by the combined value with the spring constant in the same direction, and as a result, the spring constant ratio of the elastic member in the direction perpendicular to the axis orthogonal to the axis of the mass member and the axial direction. The adjustment range of is expanded.

Further, according to the dynamic damper of the third aspect of the present invention, each annular wall is attached to the rotary shaft via the fixing member which is connected to the tip of the annular wall.

As a result, the mounting on the rotary shaft is simple and reliable, and the annular wall itself does not have a portion fixed to the rotary shaft, and the influence of the fixed portion on the function of the elastic member is reduced. The elastic deformation region of the annular wall becomes clear, and the deviation between the actual value and the planned value of the function of the elastic member is suppressed.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 indicates a dynamic damper according to this embodiment, and the dynamic damper 1 is
A cylindrical mass member 2 that is disposed around the rotation shaft S and is substantially concentric with the rotation shaft S at intervals, and an elastic member 3 that connects the mass member 2 and the rotation shaft S. And the elastic member 3 is connected to the inner surface of the mass member 2 at a substantially middle portion in the longitudinal direction thereof, and extends from the connecting portion to each end of the mass member 2, and It has a pair of annular walls 3a, 3b that are inclined so as to gradually approach the axis of the mass member 2 as they go to their respective ends, and at the tips of these annular walls 3a, 3b this elastic member 3 The schematic configuration is such that it is connected to the rotating shaft S.

More specifically, the mass member 2 is formed, for example, by cutting a metal pipe such as a steel pipe having a predetermined thickness into a predetermined length, and the surface thereof is made of natural rubber or the like. The coating layer 4 made of is formed so as to be shielded from the outside air.

As the mass member 2, other metals or materials other than metals can be used as long as a predetermined mass can be obtained.

The both annular walls 3a and 3b are made of, for example, an elastic material such as natural rubber, and the mass member 2 is provided on the outer periphery of the continuous portion of the both annular walls 3a and 3b.
A flange 3c is integrally provided along a plane orthogonal to the axis line of, and the elastic member 3 and the mass member 2 are connected via the flange 3c.

A cylindrical fixing member 5 made of an elastic material such as natural rubber is continuously provided at the tip of each of the annular walls 3a and 3b.
The inner diameter is formed to be slightly smaller than the outer diameter of the rotary shaft S and is press-fitted to the outer periphery of the rotary shaft S. In the present embodiment, the elastic members are fixed by the respective fixing members 5. 3 is connected to the rotation axis S.

Further, on the outer peripheral surface of each fixing member 5,
An annular groove 5a having a predetermined depth is formed over the entire circumference, and, for example, a metal band or the like for firmly fixing the fixing member 5 and the rotating shaft S is attached. .

In the present embodiment, the elastic member 3, the coating layer 4, and the fixing member 5 are integrally formed. For example, the mass member 2 is used as an insert member, and an insert using a mold is used. It is formed by molding.

In the molding as described above, there is an undercut portion between the elastic member 3 and both fixing members 5. The following method is a suitable method for molding the undercut portion. is there.

That is, as shown in FIG. 2, an elastic body 7 having substantially the same sectional shape as the core 6 is attached to the tips of a pair of cores 6 having the same internal shape as the fixing member 5. , The cores 6 are abutted against each other so that the elastic bodies 7 come into contact with each other in the mold, and then the cores 6 are brought closer to each other with the axes aligned with each other. By gradually expanding the diameter from the abutting surface side, as shown in FIG. 3, both elastic bodies 7 have a surface shape of the annular wall 3.
It is deformed so as to have the inner surface shape of a.

As a result, after the elastic member 3, the covering layer 4, and the fixing member 5 are molded by filling the molding rubber with the molding rubber, both cores 6 are relatively moved in the direction of separating when the mold is opened. As a result, both elastic bodies 7 in the expanded state are
Is returned to the original substantially cylindrical shape, and the core 6 and the elastic body 7 are pulled out.

By the molding method as described above, the above-mentioned undercut portion is molded and the core 6 and the elastic body 7 are smoothly demolded after molding.

Here, each of the elastic bodies 7 corresponds to the annular wall 3
It is also possible to have a truncated cone shape as shown by a chain line in FIG. 2 within a range in which it is possible to force removal utilizing the elasticity of a.

With such a shape, the deformation amount of the elastic body 7 is suppressed to a small extent, and the outer shape at the time of deformation becomes closer to the inner surface shape of the annular walls 3a and 3b.

The dynamic damper 1 of the present embodiment constructed as described above is attached to the rotary shaft S such as a drive shaft via the both fixing members 5, and the dynamic damper 1 is subjected to the vibration accompanying the rotation of the rotary shaft S. Are resonated, the rotary shaft S and the mass member 2 are relatively moved in the axial direction and the axis-perpendicular direction, and the elastic member 3 connecting the two is elastically deformed. The vibration energy of the rotating shaft S is absorbed by the elastic deformation of the above, and the vibration is suppressed.

Then, the dynamic damper 1 of this embodiment
In the above, the natural frequencies in the axial direction of the mass member 2 and in the direction perpendicular to the axis orthogonal thereto are adjusted. Regarding the setting of the spring constants of the elastic member 3 in both directions, which are necessary for setting these natural frequencies. 4 will be described with reference to FIG.

First, in the flange 3c portion, the longitudinal elastic modulus is in the direction perpendicular to the axis, and the lateral elastic modulus is in the axial direction, which coincides with the damping direction of the dynamic damper 1, respectively. The spring constants A and B in the portion 3c have values corresponding to the respective elastic moduli.

On the other hand, in the annular wall 3a, since the annular wall 3a is inclined at an angle θ with respect to the axis of the mass member 2, the longitudinal elastic modulus along the wall direction and the orthogonal to the wall. Since each of the transverse elastic moduli in the directions to be included includes the components in the axial direction and the direction perpendicular to the axis depending on the tilt angle θ, the components in each direction are combined to form the direction perpendicular to the axis and the axis. An apparent elastic modulus is generated in the direction.

Thus, the spring constant C corresponding to the longitudinal elastic modulus along the wall direction and the spring constant D corresponding to the lateral elastic modulus in the direction orthogonal to the wall are combined in accordance with the respective elastic moduli.
A spring constant Ea in the direction perpendicular to the axis and a spring constant Fa in the axial direction are used.

Here, the components of the longitudinal elastic modulus and the transverse elastic modulus of the annular wall 3a in the axial direction and the direction perpendicular to the axis are the annular wall 3a.
Is determined by the inclination angle θ of .theta., The component ratio in both directions is adjusted by changing the inclination angle .theta., Whereby the spring constant Ea in the direction perpendicular to the axis and the spring constant Fa in the axis direction are
The ratio of is adjusted.

On the other hand, the spring constants Ea.Fa in the respective directions in the annular wall 3a are similarly obtained in the other annular wall 3b, and the spring constant in the direction perpendicular to the axis of the annular wall 3b is Eb, and the axial direction Let the spring constant be Fb.

Both spring constants Ea (Eb) .F
The ratio of a (Fb) can theoretically be 0 to ∞ depending on the value of the inclination angle θ, so that a wide adjustment range is secured even in the practical range.

On the other hand, the spring constant G and the spring constant H in the direction perpendicular to the axis of the elastic member 3 as a whole are determined by the annular wall 3
It is obtained as a combined value of the spring constants in the respective directions of a. 3b and the flange 3c, and is represented by the following equations 2 and 3.

1 / G = 1 / A + 1 / (Ea + Eb) 2 equations 1 / H = 1 / B + 1 / (Fa + Fb) 3 equations Here, the right side of the equations 2 and 3 Since the second term can be adjusted by the inclination angle θ of the annular walls 3a and 3b, as described above, both spring constants G and H of the elastic member 3 as a whole are adjusted in the same manner.

As described above, in the dynamic damper 1 according to the present embodiment, the spring constant ratio between the direction perpendicular to the axis of the elastic member 3 and the axial direction is adjusted in a wide range by adjusting the inclination angle θ of the annular walls 3a and 3b. Therefore, it is possible to set the natural frequency capable of performing a reliable vibration damping action on the rotation axis S in both the axis-perpendicular direction and the axial direction.

Further, in this embodiment, each annular wall 3a is
The flange 3c extending in the direction perpendicular to the axis is interposed between the connecting portion 3b and the mass member 2,
In setting the spring constants of the elastic member 3 in the direction orthogonal to the axis and in the axial direction, the spring constants of the flange 3c in both directions are combined with the spring constants adjusted in the annular walls 3a and 3b described above. The adjustment range of both spring constants is expanded.

Further, in this embodiment, both annular walls 3
Since the fixing member 5 fitted to the rotary shaft S is continuously provided at the tips of the a and 3b, the elastic member 3 is interposed via these fixing members 5.
Is attached to the rotary shaft S, the mounting is simplified and the elastic deformation region of the elastic member 3 is clarified, and the deviation of the function of the elastic member 3 from the planned value is suppressed.

It should be noted that the shapes, dimensions, etc. of the respective constituent materials shown in the above embodiment are merely examples, and can be variously changed based on design requirements and the like.

For example, in the above embodiment, the example in which the flange 3c is provided has been shown, but the flange 3c can be omitted if the function required for the elastic member 3 is satisfied.

The fixing member 5 can also be omitted. In this case, when the elastic member 3 is attached to the rotary shaft S, it becomes necessary to directly connect the tip ends of the annular walls 3a and 3b to the rotary shaft S by bonding or welding.

[0055]

As described above, according to the first aspect of the present invention.
According to the dynamic damper described in (1), the elastic member that connects the mass member and the rotary shaft is connected to the inner surface of the mass member at a substantially middle portion in the longitudinal direction thereof, and the mass member is connected from the connecting portion. Adjusting the angle of inclination of the annular walls by providing a pair of annular walls that are inclined toward each end of the member and progressively closer to the axis of the mass member as it goes to each end. By doing so, the spring constant ratio between the direction perpendicular to the axis of the elastic member and the axial direction can be adjusted over a wide range, and it is possible to adjust the spring constant ratio in the direction perpendicular to the axis and in the axial direction without drastically changing the basic dimensions of the elastic member. The frequency can be adjusted effectively, and a reliable damping action can be obtained in any direction of the rotary shaft.

According to the dynamic damper of the second aspect of the present invention, the elastic member is formed by interposing the flange extending in the direction perpendicular to the axis between the connecting portion of the annular wall and the mass member. When setting the spring constants in the direction perpendicular to the axis and in the axial direction, the adjustment range of both spring constants of the elastic member is expanded by combining the spring constants adjusted in the annular wall with the spring constants in both directions of the flange. can do.

Further, according to the dynamic damper of the third aspect of the present invention, since the fixing member fitted to the rotating shaft is continuously provided at the tip of the annular wall, the elastic member is elastically interposed through these fixing members. By mounting the member on the rotary shaft, the mounting can be simplified, and the elastic deformation region of the elastic member can be clarified to prevent the function of the elastic member from deviating from its planned value. .

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a dynamic damper according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing an example of a method for manufacturing a dynamic damper according to an embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view showing an example of a method for manufacturing the dynamic damper according to the embodiment of the present invention.

FIG. 4 is a schematic diagram showing a state of a spring constant in the dynamic damper according to the embodiment of the present invention.

[Explanation of symbols]

 1 Dynamic damper 2 Mass member 3 Elastic member 3a / 3b Annular wall 3c Flange 5 Fixing member

Claims (3)

[Claims] 1. A cylindrical mass member which is disposed around a rotation shaft and is arranged substantially concentrically with the rotation shaft with a space therebetween.
In a dynamic damper provided with this mass member and an elastic member that connects the rotation shaft, the elastic member is connected to an inner surface of the mass member at a substantially middle portion in the longitudinal direction thereof, and this connection is made. From each part to each end of the mass member, and as it goes to each end, has a pair of annular walls inclined so as to gradually approach the axis of the mass member, and the tips of these annular walls. In the dynamic damper, the elastic member is connected to the rotating shaft. 2. A flange is continuously provided on the outer periphery of a continuous portion of both annular walls of the elastic member, the flange extending along a plane orthogonal to the axis of the mass member, and the elastic member and the mass member are connected via the flange. The dynamic damper according to claim 1, wherein the dynamic damper is connected. 3. The fixing member, which is fitted to the outer periphery of the rotating shaft, is continuously provided at a tip end portion of each annular wall. Dynamic damper.