KR20160139177A

KR20160139177A - Dynamic damper for driveshaft

Info

Publication number: KR20160139177A
Application number: KR1020150073587A
Authority: KR
Inventors: 이원구
Original assignee: 현대자동차주식회사
Priority date: 2015-05-27
Filing date: 2015-05-27
Publication date: 2016-12-07
Also published as: KR101693998B1

Abstract

The present invention relates to a dynamic damper which is mounted on a drive shaft for transmitting rotational power of an engine to a wheel to absorb and control vibration. The present invention implements a new type of dynamic damper which is robust to temperature changes by using a combination of heavy iron in a bridge increasing a spring constant, a rubber material constituting the body, and a mass acting as a mass of the dynamic damper such that the dynamic damper can reduce a change of a natural frequency according to a temperature change and, thereby providing a dynamic damper for a drive shaft which can secure the natural frequency and is robust to temperature changes.

Description

[0001] The present invention relates to a dynamic damper for a drive shaft,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic damper for a drive shaft, and more particularly, to a dynamic damper installed in a drive shaft for transmitting rotation power of an engine to a wheel to absorb and control vibration.

Generally, a drive shaft mounted on a vehicle is a part for transmitting rotational power of an engine to a wheel, and is a shaft that transmits drive torque from an end reducer to a wheel in an independent suspension type front wheel drive vehicle or a rear wheel drive vehicle.

These drive shafts can be divided into LH and RH, the dip center is offset to one side, the RH drive shaft is relatively long compared to the LH drive shaft, and the frequency band of natural frequencies due to the bending phenomenon is formed low.

As the running speed of the vehicle increases, the frequency band also becomes higher. When the natural frequency of the RH drive shaft and the frequency of the vehicle coincide, a resonance phenomenon occurs and a booming noise occurs.

Although a hollow shaft has been developed and used to increase the natural frequency of the RH drive shaft, the manufacturing process is complicated and the cost increases.

Therefore, NVH performance is improved by using dynamic damper in most types of vehicles.

If the dynamic damper is a principle gives an added mass m ₂ to reduce the amplification phenomena of the mass m ₁ resonance reduce the amplitude of the vibration is added in the opposite phase at the target frequency (the resonance frequency of the m _1).

Although vibration amplification can be reduced at the target frequency, there is a disadvantage in that the natural frequency of the damper is not robust against the influence of the surrounding environment such as temperature and humidity.

1, a dynamic damper is a structure in which a heavy object 110 such as steel is contained in a dynamic damper, and a rubber material (a natural rubber and a styrene-butadiene rubber blend) is used as the body 100.

The natural frequency of the dynamic damper varies depending on the mass (m) of the internal weight and the rigidity (k) depending on the bridge shape and the physical properties of the rubber material.

Although the drive shaft is close to the engine and has a large temperature variation range, the rubber material, which is mainly used in the damper main body structure, has a disadvantage in that physical properties such as hardness and elasticity change with temperature change.

The rigidity of the dynamic damper changes due to changes in the shape of the bridge and the physical properties of the rubber material depending on the temperature change, so that the natural frequency can not be maintained constant and the natural frequency is reduced.

For example, as the temperature increases, the mass of the damper is unchanged, but the spring constant k of the rubber becomes smaller, so that the natural frequency of the dynamic damper becomes smaller.

In consideration of this point, Korean Patent Laid-Open No. 10-2013-0046719 proposes a "dynamic damper" in which two heavy materials serving as masses are disposed inside a damper, and a thermoplastic elastomer is used to constitute a body and a damper .

However, the dynamic damper is disadvantageous in that the target natural frequency of the damper can not be firmly maintained with respect to an increase in ambient temperature.

That is, there is a drawback that the target natural frequency of the damper can not be firmly maintained because the material (thermoplastic elastomer) is used instead of the shape complement to secure the robustness against the temperature.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a dynamic damper which is robust against temperature changes by using a combination of a mass acting as a mass of a dynamic damper, a rubber material constituting the body, and a steel member in a bridge for increasing spring constant. The present invention provides a dynamic damper for a drive shaft that can reduce a change in a natural frequency according to a temperature change and thus can secure a natural frequency capable of being held firmly against a temperature change.

To achieve the above object, a dynamic damper for a drive shaft according to the present invention has the following features.

The dynamic damper for a drive shaft includes a body made of a rubber material, a mass acting as a mass formed inside the body, and a bridge formed at the front and rear ends of the body, And a steel member for reinforcing the rigidity of the bridge portion made of a rubber material is inserted.

Here, the steel members are preferably arranged in a plurality of, for example, one to three, arranged side by side along the longitudinal direction of the body at regular intervals.

The steel member may be formed in a ring shape so as to be integrally inserted into the inside of the bridge.

The dynamic damper for a drive shaft provided in the present invention has the following advantages.

First, it is possible to reduce the change of the natural frequency according to the temperature change, so that it is possible to secure the natural frequency that can be kept strong against the temperature change.

Second, it is advantageous for the durability performance of the drive shaft according to the vibration insulation improvement (avoidance of resonance phenomenon with the vehicle).

Third, it is possible to avoid booming noise caused by high-speed driving, which is advantageous for improving NVH performance of a vehicle.

1 is a cross-sectional view showing a conventional dynamic damper for a drive shaft
2 is a cross-sectional view showing a dynamic damper for a drive shaft according to an embodiment of the present invention
3 is a cross-sectional view showing a dynamic damper for a drive shaft according to another embodiment of the present invention

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a sectional view showing a dynamic damper for a drive shaft according to an embodiment of the present invention, and FIG. 3 is a sectional view showing a dynamic damper for a drive shaft according to another embodiment of the present invention.

As shown in FIGS. 2 and 3, the dynamic damper includes a cylindrical body 10 made of a rubber material, like the conventional dynamic damper, a mass material (not shown) formed in the body 10 and serving as a mass 11, and a bridge 12 made of rubber having an outer circumferential surface of a round cross-sectional shape formed at the front and rear ends of the body 10.

In particular, a steel member 13, which serves to strengthen the rigidity of the bridge portion made of a rubber material, is inserted into the bridge 12.

At this time, the steel member 13 is ring-shaped and concentrically formed with the body 10 in the inside of the bridge 12 and is integrally inserted.

Here, the steel member 13 can be integrally formed by being inserted when the body is formed.

In addition, a plurality of steel members 13 may be provided. For example, two steel members 13 may be inserted into the steel member 13 such that the steel members 13 are arranged side by side at regular intervals in the longitudinal direction of the body.

The natural frequency of such a dynamic damper changes depending on the mass m of the internal weight and the rigidity k depending on the shape of the bridge and the physical properties of the rubber material.

Here, the stiffness (k) varies depending on the shape of the bridge, but the physical properties of the rubber change with the temperature change and the stiffness changes.

If the shape of the bridge is shortened to a hexahedron, the stiffness formula for the bridge shape is as follows.

k = A / L x E

Here, L is the height of the bridge, A is the cross-sectional area of the bridge (the total cross-sectional area of the outer circumferential surface of the round cross-sectional shape portion formed along the circumferential direction), and E is the elastic modulus.

As the temperature increases, the hardness of the rubber decreases, and the characteristic (spring constant) decreases, thereby increasing the rate of change of the rubber itself.

As the drive shaft rotates, the rubber with reduced characteristics changes in the direction of centrifugal force and the height of the bridge increases.

As the height of the bridge becomes longer, the rigidity is lowered, and the frequency characteristic of the dynamic damper is also lowered.

Therefore, by inserting the steel member in the bridge height direction, the increase in the bridge height due to the change in the physical properties of the rubber at the time of increasing the temperature is suppressed, thereby reducing the frequency change in the temperature change.

Since the height of the dynamic damper applied to the drive shaft is about 5 mm and the cross-sectional area is about 3 mm in width, the thickness of the steel member is preferably about 0.5 mm, and it is preferable to apply about two steel members .

As described above, the stiffness change when the steel member is inserted into the bridge of the dynamic damper will be described below.

The total cross-sectional area A and the cross-sectional area of the rubber divided by the steel member are 2/3 A, but the rigidity is reduced by the formula k = A / L × E, but the height of the bridge is 2/3 ([2/3] × L ), It is possible to manufacture a dynamic damper that is resistant to temperature changes while maintaining rigidity.

The maximum radius of the dynamic damper is 28 mm, and there is no restriction when the height of the bridge is set to 7.5 mm when the bridge height is increased by 50% from 5 mm.

As described above, according to the present invention, by implementing a new dynamic damper in which a steel member is inserted in the bridge to increase the spring constant of the dynamic damper, it is possible to reduce the change of the natural frequency according to the temperature change, It is possible to secure the natural frequency and improve the performance of the dynamic damper.

10: Body
11: Mass (Mass)
12: Bridge
13: Steel member

Claims

And a bridge (12) formed at the front and rear ends of the body (10), a mass (11) serving as a mass formed inside the body (10) In the dynamic damper,
And a steel member (13) inserted in the bridge (12) for reinforcing the rigidity of a bridge portion made of a rubber material is inserted into the bridge (12).

The method according to claim 1,
Wherein the steel member (13) comprises a plurality of steel members (13) arranged side by side along a longitudinal direction of the body and arranged at regular intervals.

The method according to claim 1 or 2,
Wherein the steel member (13) has a ring shape and is integrally inserted into the inside of the bridge (12) in a concentric manner.