Controllable vibration apparatus

In a magnetorheological fluid damper having a damper body defining an internal cavity having an aperture formed therein, a piston rod slidably received within said aperture, a piston assembly attached to said piston rod subdividing said internal cavity into an upper chamber and a lower chamber, a magnetorheological fluid contained within said upper and lower chambers, an electrically-controllable valve controlling flow of said fluid between said upper and lower chambers, said piston assembly, comprising:

• a) a top pole piece of magnetically soft material;
• b) an annular outer ring surrounding said top pole piece also manufactured from a magnetically soft material;
• c) bridge means attaching said top pole piece to said outer ring and forming portions of a passageway between said ring and said top pole piece through which said fluid flows;
• d) a bottom pole piece connected to said piston rod and forming a another passageway portion between said ring and said bottom pole piece;
• and
• e) a coil assembly further comprising a bobbin, a wire coil which is hoop-wound about said bobbin, and at least one axially-directed, electrically-conductive pin electrically connected to said wire coil and integral with said coil assembly, said coil assembly clamped in position relative to said top pole piece and said bottom pole piece, a portion of said coil assembly surrounding an upper portion of said bottom pole piece and said electrically-conductive pin extends into a lower portion of said bottom pole piece.

A magnetorheological (MR) fluid damper, comprising:

• (a) a damper body made of magnetically soft material and at least partially defining an internal cavity which contains an amount of MR fluid therein, and
• (b) a piston assembly including
• i) a piston body which defines a portion of a magnetic circuit therein, said piston body including at least one wear band of a magnetically soft material secured about a peripheral portion thereof, said wear band also forming part of said magnetic circuit and carrying magnetic flux into said damper body,
• ii) a coil assembly for magnetically energizing said magnetic circuit and producing magnetic flux therein,
• iii) and a passageway passing through said piston containing an amount of MR fluid which changes rheology upon said energizing, said damper body forming a substantial part of said magnetic circuit.

A single tube damper, comprising:

• (a) a damper body, having an end cap and a top cap defining an internal cavity containing an amount of liquid therein and having an aperture in said top cap,
• (b) a piston rod slidingly received in said aperture,
• (c) a piston secured to one end of said piston rod subdividing said internal cavity into two chambers, said piston including a first flux carrying member and a second flux carrying member cooperating to define at passageway and a coil assembly to generate a magnetic flux when energized which acts between said members and upon said fluid in said passageway,
• (d) circuit means including a single-strand electrical conductor electrically connected to said coil assembly, a flexible sealing element closely surrounding said electrical conductor, and means for compressing the sealing element such that the flexible sealing element expands into sealing engagement with said electrical conductor, and
• (e) a diaphragm assembly interacting with one of said two chambers and partially defining an accumulator chamber which is devoid of liquid, said diaphragm assembly being capable of movement in response to movement of said piston, said accumulator chamber being pressurized to between 100-500 psi without a fill valve.

A magnetorheological (MR) fluid damper, comprising:

• (a) a damper body at least partially defining an internal cavity which contains an amount of MR fluid therein and which has an aperture formed therein.
• (b) a piston rod slidingly received in said aperture, and
• (c) a piston assembly attached to said piston rod, subdividing said internal cavity into two chambers, said piston assembly including first and second flux carrying members cooperating to define a passageway and a coil assembly adapted to generate a magnetic flux which acts upon said passageway when energized, said piston assembly further including a wear surface for reducing friction between said piston assembly and said damper body which includes a primary metallic layer coated with a friction reducing surface treatment selected from a group consisting of porous bronze, nickel, fluorinated polyethylene polymer, and combinations thereof, and
• (d) circuit means including a single-strand electrical conductor electrically connected to said coil assembly, a flexible sealing element closely surrounding said electrical conductor, and means for compressing the sealing element such that the flexible sealing element expands into sealing engagement with said electrical conductor.