Brakes – Inertia of damping mass dissipates motion – Resiliently supported damping mass
Reexamination Certificate
2000-05-02
2002-08-27
Dickson, Paul N. (Department: 3613)
Brakes
Inertia of damping mass dissipates motion
Resiliently supported damping mass
C267S293000, C267S140110, C267S140200
Reexamination Certificate
active
06439359
ABSTRACT:
TECHNICAL FIELD
This invention relates to a vibration restraining apparatus for a vehicle attached to a vibration transmitting member to restrain a harmful vibration occurring therein. Here, the vibration transmitting member includes a suspension arm, sub frame, body panel, engine mounting bracket, engine unit or exhausting device of an automobile, and an arm member or a body panel of an electric train.
BACKGROUND ART
A running vehicle such as an automobile for example generates a vibration by operation of an engine as a power source, and the generated vibration is inputted into the road through surface during running of the vehicle. These vibrations are in turn transmitted to the vehicle body through an engine mounting bracket or a vehicle body frame supporting an engine unit or a suspension arm or sub frame connected to wheels. If a natural resonance occurs in these vibration transmitting members, the vibration transmission to the vehicle body is amplified to cause noise in the vehicle room and vibration of vehicle frame.
In view of the above, in the prior art, the vibration occurred in those vibration transmitting member is restrained or damped by attaching a mass damper, dynamic damper or a vibration restraining member.
The above mass damper is constructed by adding a mass (weight) to the vibration transmitting member, so that the natural vibrating frequency of the vibration restraining member is varied, thus restraining a target vibration. However, more mass needs to be added for obtaining sufficient vibration restraining effect by the mass damper, which increases the weight of the mass damper.
Also, the above dynamic damper is a vibration absorbing apparatus constructed by a portion attached to the vibration transmitting member, a mass (mass body) disposed apart from the attach portion, a rubber elastic body (spring) disposed between the mass and the attached portion and connects them integrally. This dynamic damper is attached to the vibration transmitting member at an attached portion thereof to reduce amplitude of the vibration transmitting member by resonance of the mass/rubber elastic body in resonances of the vibration transmitting member in resonance vibration.
However, the resonance frequency of this dynamic damper is determined based on weight of the mass body and spring constant of the rubber elastic body, so the dynamic damper can restrain the vibration at only one frequency area in the resonance occurred in the vibration transmitting member, but is not effective with respect to plural resonances. Also, the weight of the mass body and the spring constant of the rubber elastic body are set based on applying a direction of them (vibration direction) determined by the positional relation between the mass body and the rubber elastic body, and therefore have directionality. Accordingly, restraining the vibrations in many directions simultaneously by one dynamic damper is difficult. Also, the spring constant of the rubber elastic body used as the spring easily varies depending on temperature and has a large temperature dependency, so that the vibration restraining effect is deteriorated at a high temperature and at a low temperature.
The above vibration restraining member is formed like a sheet by single layer or plural layers made of asphalt, urethan, acrylic resin or metallic plate, and is adhered to a surface of the panel-like vibration transmitting member such as a roof panel or floor panel for use. The vibration restraining member deforms elastically corresponding to resonance of the vibration transmitting member to absorbs a vibrating energy of the vibration transmitting member by an internal friction generated at that time, thereby damping resonance of the vibration transmitting member.
However, such vibration restraining member needs to be adhered to the vibration transmitting member in rather broad area, and has larger weight due to a forming material of relatively large specific gravity. In addition, due to the temperature dependency of the vibration restraining member, the vibration restraining effect may be decreased at a high temperature and low temperature when the vibration restraining member is tuned at the room temperature.
Thus, the mass damper, dynamic damper and vibration restraining member which have been conventionally used have above problems.
DISCLOSURE OF INVENTION
The present invention is made in view of the above circumstances and has a subject matter or purpose to provide a vibration restraining apparatus for vehicle which can be lightened in weight, does not have the temperature dependency, and can perform the vibration restraining effect for plural resonances having different frequencies.
A vibration restraining apparatus of the present invention is featured by a housing made of a rigid material and having an inner space, and fixed to a vibration transmitting member; and a filled member sealed in the inner space of the housing in a non-adhered state with leaving a gap with respect to a vibrating direction of the housing, and formed by an elastic body at least at a surface thereof.
In this vibration restraining apparatus for vehicle, when the housing resonates by the vibration transmitted from the vibration transmitting member, the filled member contacts (abuts) with (onto) inner surfaces of the housing at both sides in the vibrating direction, so that the damping character of the filled member relative to the housing due to an energy loss caused by a sliding friction and a collision is exercised. In this way, the large damping character occurs inside the housing to restrain the vibration of the housing effectively. As a result, the vibration of the vibration transmitting member is effectively restrained.
In the vibration restraining apparatus for vehicle of the present invention, the damping character is exercised based on the energy loss caused by the sliding friction and the collision generated when the filled member constants (abuts) with (onto) the inner surface of the housing, so the damping character can be exercised for plural resonances of different frequencies. Also, the vibration damping operation does not have the temperature dependency since the amount of the loss energy due to the sliding friction and the collision is hardly affected by the temperature.
In addition, in the vibration restraining apparatus for vehicle, since the gap formed between the inner surface of the housing and the filled member can be freely set corresponding to a vibrating direction of the housing (vibrating direction of vibration transmitting member), the vibration in the all directions of the housing can be restrained.
Here, when the housing is lightened, vibration of the housing may increase corresponding to a decrease in inertia if the inputted vibration is constant. However, the vibration is damped by disposing the filled member in the inner space of the housing by leaving the gap in the vibration restraining apparatus for a vehicle of the present invention, so lightening of the housing can be realized without worsening the vibration.
Accordingly, the vibration restraining apparatus for vehicle can be lightened, does not have the temperature dependency, and can exercise the vibration restraining effect for plural resonances of different frequencies. Here, the vibration restraining apparatus for vehicle of the present invention can be attached to all kinds of the vibration transmitting members of the vehicle to restrain the vibration thereof satisfactorily.
The vibration restraining apparatus for vehicle of the present invention can be embodied by various means or modes to be explained below.
That is, the housing of the present invention is formed by a rigid material and has a closed inner space therein. As the rigid material for forming the housing, metals such as an iron or an aluminium alloy etc. or a hard resin can be adopted, for example. These rigid materials preferably have an elasticity rate more than 5×10
4
MPa. If the elasticity rate is smaller than 5×10
4
MPa rigidity of the housing becomes insufficient, so that shape of
Hamada Masaaki
Hattori Shigemitsu
Ikaga Syuji
Kato Rentaro
Maeno Hajime
Dickson Paul N.
Kramer Devon
Tokai Rubber Industries Ltd.
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