Brakes – Inertia of damping mass dissipates motion
Reexamination Certificate
2001-03-13
2004-04-13
Butler, Douglas C. (Department: 3683)
Brakes
Inertia of damping mass dissipates motion
C267S136000, C267S141000, C267S292000, C188S268000
Reexamination Certificate
active
06719108
ABSTRACT:
This application is based on Japanese Patent Applications No. 2000-086158 filed Mar. 27, 2000, the contents of which are incorporated hereinto by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a vibration damper installed in a vibrative member of a vehicle, for reducing or attenuating vibration of the vibrative member. More particularly, the present invention is concerned with such a vibration damper which is novel in construction and which is suitably applicable to vibrative members such as suspension arms, sub frames, body panels, mounting brackets, and vibrative members used in an engine unit or an exhaustion system, so that the vibration damper exhibits an excellent damping effect with respect to vibrations excited in these vibrative members.
2. Description of the Related Art
As vibration damping means for damping or reducing vibration excited in vehicles such as an automotive vehicle, there are known (a) a mass damper wherein a mass member is fixed to a vibrative member, (b) a dynamic damper wherein a mass member is supported by and connected to the vibrative member via a spring member and (c) a damping material which is a sheet-shaped elastic member and secured to the vibrative member. However, these conventional devices suffer from various potential problems. For instance, (a) the mass damper and (b) the dynamic damper both require a relatively large mass of the mass member, and exhibit desired vibration damping effect only to significantly narrow frequency ranges. (c) The damping material suffers from difficulty in stably exhibiting a desired damping effect, since the damping effect of the damping material is prone to vary depending upon the ambient temperature.
The present assignee has been disclosed in International Publication WO 00/14429 a novel vibration damper used for an automotive vehicle, which includes a housing member having an inner space and fixed to the vibrative member, and an independent mass member which is accommodated in the inner space of the housing member without being bonded to the housing member, so that the independent mass member is displaceable or movable relative to the housing member, while being independent of the housing member. In the disclosed vibration damper, the independent mass member is forced to move into and impact the housing member, upon application of a vibrational load to the damper, whereby the vibration of the vibrative body is effectively reduced or absorbed based on loss or dissipation of energy caused by sliding friction generated between the abutting surfaces of the mass member and the housing member and caused by collision or impact of the independent mass member against the housing member. This proposed vibration damper is capable of exhibiting a high damping effect over a sufficiently wide frequency range of frequency of input vibrations, while having a relatively small mass of the mass member.
In order to stably establish a desired damping effect of the vibration damper disclosed in the above-indicated document, it is required that the independent mass member is brought into impact directly against the housing member in a vibration input direction in which vibrations to be damped is applied to the vibration damper. In the case where the vibrational loads are applied in various vibration input directions to the vibration damper, for example, there is a need for disposing the independent mass member in the accommodation space such that the independent mass member is movable or displaceable relative to the housing member in every vibration input direction.
In order to stably exhibit a desired damping effect, the vibration damper is further required to effectively provide a bouncing displacement or movement of the independent mass member in the accommodation space, upon application of a vibrational load to the vibration damper, whereby the independent mass member is repeatedly brought into impact on and bounce off the housing member so as to repeatedly apply impact energy to the housing member. To meet this end, there is a need for reducing friction at an interface formed between the independent mass member and the housing member upon abutting or sliding contact of the independent mass member with the housing member.
In order to stably establish the desired damping effect of the vibration damper, there is yet further required to stabilize the condition of the impact between the independent mass member and the housing member. For instance, it should be stabilized an abutting portion or an abutting surface area of the independent mass member at which the independent mass member impacts on the housing member.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide an improved vibration-damping device for vehicles capable of exhibiting a desired damping effect with respect to vibrations applied thereto in a plurality of vibration input directions.
It is another object of this invention to provide an improved vibration-damping device for vehicles, which permits a decreased friction at the interface formed between the independent mass member and the housing member, upon abutting or sliding contact of the independent mass member with the housing member, leading to decrease in frictional resistance to the displacement of the independent mass member. This vibration damping-device therefore facilitates the bouncing displacement of the independent mass member relative to the housing member, thereby exhibiting an improved vibration damping effect.
It is yet another object of this invention to provide an improved vibration-damping device for vehicles capable of exhibiting a desired damping effect with high stability, owing to stabilized condition of impact of the independent mass member on the housing member.
The above object may be achieved according to the principle of the present invention, which provides a vibration-damping device for damping vibrations of a vibrative member of a vehicle, comprising: (a) a rigid housing member formed integrally with or independently of the vibrative member and being subjected to the vibrations of the vibrative member, the housing member defining an accommodation space; and (b) an independent mass member having a spherical outer surface and disposed non-adhesively in the accommodation space such that the independent mass member is opposed to an inner surface of the housing member defining the accommodation space, with a spacing therebetween, and is displaceable relative to the inner surface of the housing member. The independent mass member and the housing member are brought into direct and elastic impact against each other at respective abutting surfaces thereof in at least one vibration input direction, upon application of the vibrations in the at least one vibration input direction.
In the vibration-damping device of the present invention constructed as described above, the independent mass member has the spherical outer surface. This arrangement makes it possible to arrange the independent mass member to directly and elastically impact against the housing member in a plurality of optional vibration input directions, by only adjusting suitably the configuration of the accommodation space defined by the inner surface of the housing member. Therefore, the vibration-damping device can exhibits an excellent damping effect with respect to vibrations applied in the plurality of vibration input directions.
In the vibration-damping device of the present invention, the independent mass member is brought into abutting or sliding contact with the housing member with a relatively small contact area, owing to its spherical outer surface, leading to a low resistance to the displacement of the independent mass member. For instance, the independent mass member is less likely to be caught in the housing member during its bouncing displacement within the accommodation space of the housing member. This arrangement facilitates the bouncing movement of the independent mass member in the accommodation space of the
Hasegawa Koichi
Kato Rentaro
Beyer Weaver & Thomas LLP
Butler Douglas C.
Tokai Rubber Industries Ltd.
LandOfFree
Virbration damping device for vehicles does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Virbration damping device for vehicles, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Virbration damping device for vehicles will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3213885