Spring devices – Resilient shock or vibration absorber – Including energy absorbing means or feature
Reexamination Certificate
2000-04-17
2001-08-21
Graham, Matthew C. (Department: 3613)
Spring devices
Resilient shock or vibration absorber
Including energy absorbing means or feature
Reexamination Certificate
active
06276673
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to a fluid-filled vibration damping device having an electromagnetic actuator adapted to oscillate or displace an oscillating member which partially defines a fluid chamber formed in the vibration damping device, for controlling the pressure of a fluid in the fluid chamber, in order to actively damp vibration to be damped. More particularly, this invention is concerned with such a fluid-filled active vibration damping device which is capable of oscillating or displacing the oscillating member with high stability and efficiency and which is suitably used as an engine mount, a body mount or a cab mount for a motor vehicle, for example.
2. Discussion of the Related Art
As one type of a vibration damper or a vibration damping connector which is interposed between a vibration source and an object whose vibration is to be damped, there is known a fluid-filled active vibration damping device including: (a) a first and a second mounting member which are spaced apart from each other; (b) an elastic body which elastically connects the first and second mounting members and which partially defines a fluid chamber filled with a non-compressible fluid; (c) an oscillating member which partially defines the fluid chamber; (d) an actuator for oscillating the oscillating member; (e) a flexible diaphragm which partially defines an equilibrium chamber filled with the non-compressible fluid; and (f) means for defining an orifice passage for fluid communication between the equilibrium chamber and the fluid chamber.
In such an active vibration damping device, the oscillation or displacement of the oscillating member is controlled on the basis of characteristics of vibration, such as its frequency or amplitude, for thereby controlling the pressure of the fluid in the fluid chamber, so that the vibration is actively or positively damped. It is proposed to employ such an active vibration damping device as an engine mount for a motor vehicle, in view of its capability to provide a sufficiently high vibration damping effect with respect to vibration whose frequency and amplitude are variable.
For such an active vibration damping device to be able to stably and effectively provide a desired vibration damping effect, it is necessary that the oscillation of the oscillating member is stably and efficiently controlled. In this respect, there has been proposed an active vibration damping device as disclosed in JP-A-59-1829 and JP-A-61-2939, which has an electromagnetic actuator adapted to oscillate or displace the oscillating member. In this active vibration damping device, the oscillating member is driven by an electromagnetic force, i.e. a magnetic force generated by an electromagnet, so that the oscillation of the oscillating member is easily and accurately controlled.
However, even such an active vibration damping device equipped with the electromagnetic actuator suffers from deterioration of stability of the displacement of the oscillating member, since the oscillating member, upon displacement thereof, tends to be inclined by, for example, a force other than the electromagnetic force applied thereto by one or more other element or member of the vibration damping device, resulting in difficulty in providing a desired vibration damping effect, with high stability, irrespective of operating conditions. For solving this drawback, it is considered possible to use a guide mechanism in which the oscillating member is slidably guided by a slideway or slide bushing in an oscillation direction in which the oscillating member is displaced or oscillated, so as to prevent or minimize inclination of the oscillating member with respect to the oscillation direction. However, the sliding movement of the oscillating member on the slideway or in the slide bushing tends to generate an undesirable noise and heat due to a frictional resistance between the oscillating member and the slideway or bushing, and even deteriorate the oscillation motion of the oscillating member due to an energy loss. In this respect, the use of the electromagnetic actuator as means for oscillating the oscillating member still has a technical problem to be solved.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a fluid-filled active vibration damping device having a novel structure, which elastic mount is capable of oscillating or displacing the oscillating member with high stability and efficiency, so as to effectively exhibit desired vibration-damping effect with high stability.
The present invention provides a fluid-filled active vibration damping device according to each of the following aspects, preferred forms or advantageous arrangements of the invention. It is to be understood that the following preferred forms and advantageous arrangements are provided to facilitate the understanding of possible combinations of features recited in the following preferred forms and advantageous arrangements, and that the technical features and the combinations of the technical features disclosed in the present specification are not limited to the following preferred forms and advantageous arrangements, but should be recognized based on the overall description of the specification and the drawing.
The above object may be achieved according to the principle of the present invention, which provides a fluid-filled active vibration damping device comprising: (a) a first and a second mounting member which are spaced apart from each other; (b) an elastic body which elastically connects the first and second mounting members and which partially defines a fluid chamber filled with a non-compressible fluid; (c) an oscillating member which partially defines the fluid chamber; (d) an electromagnetic actuator for oscillating the oscillating member, so as to control a pressure of the non-compressible fluid in the fluid chamber; (e) a stabilizing member which is disposed on one of opposite sides of the oscillating member that is remote from the fluid chamber, and which is opposed to and spaced apart from the oscillating member in an oscillation direction in which the oscillating member is oscillated by the electromagnetic actuator; (f) a first elastic support through which the oscillating member is elastically supported by the second mounting member such that the oscillating member is displaceable relative to the second mounting member; (g) a second elastic support through which the stabilizing member is elastically supported by the second mounting member such that the stabilizing member is displaceable relative to the second mounting member; and (h) a connecting member which connects the oscillating member and the stabilizing member, so as to cooperate with the oscillating member and the stabilizing member to provide a displaceable assembly which is displaceable relative to the second mounting member.
In the fluid-filled active vibration damping device constructed according to the invention, the oscillating member and the stabilizing member are spaced apart from each other in the oscillation direction in which the oscillating member is oscillated by the electromagnetic actuator, and are connected to each other by the connecting member so as to provide the displaceable assembly. The oscillating member and the stabilizing member are elastically supported by the second mounting through the respective first and second elastic supports. That is, the displaceable assembly is elastically supported by the second mounting member, at two portions thereof, i.e., at the oscillating member and the stabilizing member which are distant from each other in the oscillation direction. Accordingly, a positioning force applied from the first and second elastic supports acts on the two portions of the displaceable assembly which are distant from each other in the oscillation direction, thereby minimizing inclination of the oscillating member with respect to the oscillation direction or displacement of the oscillating member in a direction perpendicular to the osc
Akasa Shouji
Hibi Masayuki
Muramatsu Atsushi
Saiki Akio
Burr & Brown
Graham Matthew C.
Tokai Rubber Industries Ltd.
LandOfFree
Fluid-filled active vibration damping device having... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fluid-filled active vibration damping device having..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fluid-filled active vibration damping device having... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2546803