Variable torsional damper having magneto-rheological fluid damping in parallel with a spring damper

A variable torsional damper rotatably supported for translating torque between a prime mover and the input of a transmission, said variable torsional damper comprising:

• a torque input member operatively connected for rotation with the power take off of a prime mover, an output member operatively connected for rotation with the input to a transmission and a plurality of damping members interposed between said input member and said output member, said damping members acting to translate torque between said input and said output members and to dampen torsional forces generated between the prime mover and the transmission;
• and
• a magneto-rheological damper assembly having a magnetic coil assembly, an inner disk assembly, and an outer disk assembly, said magnetic coil assembly including a winding that is adapted to provide a selectively variable magnetic field having two magnetic poles when selectively energized, said inner disk assembly operatively supported by said input member and including a riser portion and a flux-shaping ring, said flux-shaping ring mounted to said riser portion and operatively supported about said magnetic coil assembly such that the magnetic lines of flux generated by said magnetic coil assembly flow through said flux-shaping ring, said outer disk assembly operatively supported by said output member such that said magneto-rheological damper assembly is disposed in parallel with said damping members, and magneto-rheological fluid operatively disposed between said inner disk and said outer disk such that said magneto-rheological fluid is influenced by said magnetic field to cause additional hysteresis to be added to that provided by said damping members.

A variable torsional damper rotatably supported for translating torque between a prime mover and the input of a transmission, said variable torsional damper comprising:

• a torque input member operatively connected for rotation with the power take off of a prime mover, an output member operatively connected for rotation with the input to a transmission and a plurality of damping members interposed between said input member and said output member, said damping members acting to translate torque between said input and said output members and to dampen torsional forces generated between the prime mover and the transmission;
• a magneto-rheological damper assembly having an inner disk assembly that is operatively supported by said input member, an outer disk assembly that is operatively supported by said output member such that said magneto-rheological damper assembly is disposed in parallel with said damping members, and a magnetic coil assembly having two poles that is adapted to provide a magnetic field when selectively energized;
• said inner disk assembly including a flux-shaping ring and said outer disk assembly including a flux-shaping ring and a flux-channeling ring, said flux-shaping ring and a flux-channeling ring of said outer disk assembly operatively surrounding said flux-shaping ring of said inner disk assembly and forming a magneto-rheological fluid cavity that retains magneto-rheological fluid;
• said flux-shaping rings of said inner disk assembly and said outer disk assembly each having two outer rings and a center ring, said outer rings formed of a magnetically permeable material and said center ring formed of a non-magnetically permeable material and adapted to block the generated magnetic lines of flux and cause them to flow through said two outer rings, said flux-channeling ring of said outer disk assembly is formed of a magnetically permeable material that is adapted to cause the generated magnetic lines of flux to flow between the two poles of said magnetic coil assembly after flowing through said flux-shaping rings of said inner and said outer disk assemblies, such that the magnetic lines of flux generated by said magnetic field are shaped by said flux shaping portions to provide a perpendicular flow of magnetic flux lines through said cavity to cause said magneto-rheological fluid to be influenced to selectively add additional hysteresis to that of the damping members.