Adaptive transfer case with EM clutch and dog clutch for 4WD lock up
DCFirst Claim
1. A transfer case for providing torque to a first driveline and a second driveline comprising, in combination,an input for receiving torque,a first output adapted to receive torque from said input and coupled to such first driveline and a second output coupled to such second driveline and a clutch assembly operably disposed between said first output and said second output,said clutch assembly having a first electromagnetic operator capable of modulatably engaging said first and said second outputs in a first state and coupling said first and said second outputs in a second state and a second electromagnetic operator for selectively maintaining said first and said second outputs in said second state.
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Abstract
An adaptive torque control and distribution system for a motor vehicle having a transfer case, primary driveline and drive wheels and secondary driveline and drive wheels for operation in extreme off road conditions such as sand. The transfer case includes a modulating clutch and a lockup clutch disposed in parallel between its primary (rear) output and secondary (front) output. The system detects abnormally high magnitude and rapidly repeating wheel spin transients which are characteristic of operation in sand or similar highly randomly variable tractive conditions and overrides the on demand torque distribution program for a predetermined time interval. During this predetermined time interval, the transfer case lockup clutch is activated thereby coupling the primary and secondary drivelines and achieving a fifty-fifty torque split therebetween while the modulating clutch is inactive. The system and this operating mode reduces clutch and clutch operator cycling thereby reducing heat generation within the transfer case and increasing clutch and transfer case longevity.
61 Citations
20 Claims
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1. A transfer case for providing torque to a first driveline and a second driveline comprising, in combination,
an input for receiving torque, a first output adapted to receive torque from said input and coupled to such first driveline and a second output coupled to such second driveline and a clutch assembly operably disposed between said first output and said second output, said clutch assembly having a first electromagnetic operator capable of modulatably engaging said first and said second outputs in a first state and coupling said first and said second outputs in a second state and a second electromagnetic operator for selectively maintaining said first and said second outputs in said second state.
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6. A transfer case for providing drive torque to a first driveline and a second driveline of a motor vehicle comprising, in combination,
a first output adapted to drive said first driveline, a second output adapted to drive said second driveline and a clutch assembly operably disposed between said first output and said second output, said clutch assembly having a first electromagnetic operator assembly capable of adjustably engaging said first output and said second output and fully engaging said first and said second outputs, and a second electromagnetic operator assembly for selectively maintaining said first output and said second output in such fully engaged condition.
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11. An adaptive four-wheel drive system for a motor vehicle for controllably distributing torque between a primary driveline and a secondary driveline, wherein the system does not have a geared differential for coupling the primary driveline and secondary driveline, comprising, in combination,
an input member adapted to receive torque, a primary output arrangement adapted to be driven by the input member and drive the primary driveline, a secondary output arrangement adapted to drive the secondary driveline, means for determining the rotational speed difference between the primary output arrangement and the secondary output arrangement, an electrically powered mover adapted to be activated in response to the sensed speed difference, a friction clutch assembly activated by the electrically powered mover whereby torque is supplied to the secondary output arrangement so that the primary output arrangement and the secondary output arrangement are concomitantly driven; - and
a controller adapted to modulate electrical power supplied to the electrically powered mover for a first predetermined period of time in response to said sensed speed difference, and if a predetermined sensed speed difference exists at the end of the first predetermined period, substantially simultaneously for a second predetermined period of time a) engage a locking mechanism to maintain the supply of torque to the second output arrangement so that the primary output arrangement and secondary output arrangement are concomitantly driven and b) cease supplying electrical power to the electrically powered mover. - View Dependent Claims (12, 13, 14)
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15. A transfer case assembly for a four-wheel drive motor vehicle comprising, in combination,
an input member driving a first output member, a second output member and a clutch assembly operably disposed between said first output member and said second output member, said clutch assembly having a first electric operator for effecting adjustment of a level of torque transferred between said first output and said second output and a second electric operator for effecting a maximum level of torque transfer between said first output and said second output, and a controller for first increasing a first drive signal to said first electric operator to provide such maximum level of torque transfer, providing a second drive signal to said second electric operator to maintain such maximum level of torque transfer and reducing said first drive signal to said first electric operator.
Specification