Selective drive fluid coupling
AssigneeMileMarker, Inc.
InventorsRichard E. Aho, Martin Baker
Life of this patent
Estimating the term…
Abstract
The specification discloses a fluid coupling for connecting rotatable shafts. In one embodiment, rotation of an output shaft is transferred to a drive shaft by a pair of opposed rotatable rings having interleaved fins. The interleaved fins provide fluid filled chambers and relative movement of the fins compresses the fluid and increases the ability of the fluid to transfer torque.
Claims7
A fluid coupling for use in a drive train to couple a first rotatable member to a second rotatable member to provide rotation of the first and second rotatable members without substantial relative movement of the members during normal operation of the vehicle when the torque in the drive train exerted upon the coupling does not exceed a predetermined break-away torque, said coupling comprising:
- reservoir means positioned between said first and second rotatable members for containing a highly viscous fluid, said fluid having a viscosity sufficiently great so that the first rotatable member and the second rotatable member rotate substantially in unison during normal operation when the torque exerted upon the coupling is below the break-away torque;
- pump means associated with said reservoir means for exerting pumping forces on said viscous fluid to transfer torque from said first rotatable member to said second rotatable member when the break away torque of the coupling is exceeded, said pump means comprising:
- a first rotatable body having a first pump surface rotatable in response to rotation of said first rotatable member for exerting pumping forces on said fluid,
- a second rotatable body having a second pump surface rotatable in response to the pumping forces and associated with said second rotatable member for transmitting pumping forces from said fluid to said second rotatable member when the break away-torque of the coupling is exceeded so that torque is transferred from the first member to the second member when the first and second members rotate relative to one another, and
- at least one chamber defined between said first and second pump surfaces for containing an amount of said viscous fluid, said chamber being movable relative to said first pump surface in response to relative movement between said first and second pump surfaces when the break away torque of the coupling is exceeded to produce the pumping forces, so that when the break-away torque is exceeded the torque transfer remains above a level of about the breakaway torque,
- said pump means being configured, and the viscosity of said fluid being sufficiently great, so that the break-away torque is substantially greater than zero and is about equal to or greater than the normal operating torque of the drive train.
A fluid coupling for use in a drive train to couple a first rotatable member to a second rotatable member to provide rotation of the first and second rotatable members without substantial relative movement of the members during normal operation of the vehicle when the torque in the drive train exerted upon the coupling does not exceed a predetermined break-away torque, said coupling comprising:
- reservoir means positioned between said first and second rotatable members for containing a highly viscous fluid, said fluid having a viscosity sufficiently great so that the first rotatable member and the second rotatable member rotate substantially in unison when the torque exerted upon the coupling is below the break-away torque;
- pump means associated with said reservoir means for exerting pumping forces on said viscous fluid to transfer torque from said first rotatable member to said second rotatable member when the first and second rotatable members rotate relative to one another, said pump means comprising:
- a first rotatable body having a first pump surface rotatable at a first rate in response to rotation of said first rotatable member for exerting pumping forces on said fluid when the break-away torque is exceeded,
- a plurality of substantially cylindrical substantially concentric first fins extending outwardly from said first rotatable body in an axial direction, said first pump surface being defined on said first fins,
- a second rotatable body having a second pump surface rotatable at a second rate in response to the pumping forces and associated with said second rotatable member for transmitting pumping forces from said fluid to said second rotatable member when the break-away torque is exceeded,
- a plurality of substantially cylindrical substantially concentric second fins extending outwardly from said second rotatable body in an axial direction, said second pump surface being defined on said second fins,
- said first and second fins being disposed in an interleaved substantially concentric relationship in which each of said first fins is adjacent one of said second fins and said highly viscous fluid is disposed between adjacent first and second fins.
A fluid coupling for use in a drive train to couple a first rotatable member to a second rotatable member to provide rotation of the first and second rotatable members without substantial relative movement of the members during normal operation of the vehicle when the torque in the drive train exerted upon the coupling does not exceed a predetermined break-away torque and to provide relative rotation of the first and second rotatable members and to transfer torque from the first rotatable member to the second rotatable member when torque conditions above the predetermined break-away torque are encountered, said coupling comprising:
- a first rotatable body for mounting on and rotating with the first rotatable member;
- a second rotatable body for mounting on and rotating with the second rotatable member;
- a plurality of substantially cylindrical substantially concentric first fins extending outwardly from said first rotatable body in an axial direction and defining a plurality of substantially cylindrical substantially concentric cavities;
- a plurality of substantially cylindrical substantially concentric second fins extending outwardly from said second rotatable body in an axial direction, each of said second fins being disposed within one of said cavities;
- a highly viscous fluid disposed within said cavities for contacting said first and second fins, said fluid having a viscosity sufficiently great so that the first rotatable member and the second rotatable member rotate substantially in unison when the torque exerted upon the coupling is below the break-away torque and rotate relative to one another when the torque exerted upon the coupling is above the break-away torque so that when the break-away torque is exceeded the torque transfer remains above a level of about the break-away torque;
- support means associated with said first and second rotatable bodies for maintaining said second fins within said cavities;
- and
- seal means associated with said first and second rotatable bodies and defining a sealed reservoir around said first and second fins for containing said viscous fluid.
Dependencies are inferred from the claim text.