Two-way magnetorheological fluid valve assembly and devices utilizing same

DETAILED DESCRIPTION In light of the advantages and drawbacks of prior art MR devices, the present invention is a controllable valve assembly of the MR variety which is particularly useful for application in MR mountings and MR linear dampers, for passively producing "asymmetrical" damping in the various operating directions.
For example, the "asymmetry" may take the form of different damping rates in the "compression" and "extension" directions.
In a point of novelty, this "asymmetrical" feature is achieved via various "passive" means, therefore, eliminating the need to "rapidly switch" the current applied to the valve assembly, as required in prior art MR devices thereby dramatically simplifying electronic control needs.
In a first novel aspect, the "asymmetrical" damping characteristic is achieved by implementing a "changeable flow gap" within the controllable passageway which is exposed to magnetic field by implementing a moveable wall portion of a magnetic return member which moves relative to another portion of the valve body.
Preferably, the magnetic circuit is oriented such that magnetic body forces on the magnetic return are minimized.
This "changeable gap" dimension of the controllable passageway is variable as a function of flow direction.
The "changeable gap" may be achieved by spring-loading of the wall portion of the controllable MR passageway, such that the gap widens or narrows as a function of flow direction, thereby changing the reluctance of the magnetic circuit and, resultantly, changing the damping characteristics of the particular valve or device by changing the magnetic field strength acting upon the magnetically controlled fluid contained within the MR controllable passageway.
In a second novel aspect, the "asymmetrical" damping characteristic is achieved by providing a "separate passive passageway" including a "one-way check valve" operative therewith.
The passive passageway is located in parallel relationship to the MR controllable passageway and provides the means for preferably substantially restricting flow through the passive passageway in a first flow direction, yet allowing substantial flow in a second flow direction