Four-wheel motor vehicle drive transfer case with limited differentiation
First Claim
1. A four-wheel drive system for a vehicle having an engine and a transmission and including a torque transfer case for dividing torque for front and rear axles of the vehicle, said torque transfer case comprising:
- an input shaft coupled to the transmission to be rotatably driven thereby;
a first output shaft to transmit torque to a first axle of the vehicle;
a second output shaft to transmit torque to second axle of the vehicle;
an interaxle differential disposed between said input shaft and said first and second output shafts for transmitting torque from said input shaft to said first and second output shafts, and allowing said first and second output shafts to rotate differentially with respect to one another;
a first one-way clutch to selectively lock said interaxle differential such that said first and second output shafts are rotatably coupled to one another when said second output shaft overruns said first output shaft; and
a second one-way clutch to selectively lock said interaxle differential such that said first and second output shafts are rotatably coupled to one another when said first output shaft overruns said second output shaft by a predetermined amount.
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Accused Products
Abstract
A four-wheel motor vehicle drive transfer case with limited differentiation is designed to provide full time four-wheel drive and limit slip or differentiation between the rear and front wheels of a motor vehicle using a mechanical system. The torque transfer case allows differentiation between the front and the rear wheels of the motor vehicle up to a predetermined threshold and thereafter prevents differentiation so that the torque to the axle with the slipping wheels is redirected and transmitted to the axle with the non-slipping wheels. Preferably, an interaxle differential in the torque transfer case locks whenever the rear output shaft attempts to overrun the front output shaft. Also, the torque transfer case preferably allows the front drive shaft to overrun the rear drive shaft by that amount that occurs during "normal" motor vehicle turning and cornering operations or that amount which may occur due to differences in tire static loaded radius and thereafter locks the interaxle differential to prevent any further differentiation.
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Citations
27 Claims
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1. A four-wheel drive system for a vehicle having an engine and a transmission and including a torque transfer case for dividing torque for front and rear axles of the vehicle, said torque transfer case comprising:
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an input shaft coupled to the transmission to be rotatably driven thereby; a first output shaft to transmit torque to a first axle of the vehicle; a second output shaft to transmit torque to second axle of the vehicle; an interaxle differential disposed between said input shaft and said first and second output shafts for transmitting torque from said input shaft to said first and second output shafts, and allowing said first and second output shafts to rotate differentially with respect to one another; a first one-way clutch to selectively lock said interaxle differential such that said first and second output shafts are rotatably coupled to one another when said second output shaft overruns said first output shaft; and a second one-way clutch to selectively lock said interaxle differential such that said first and second output shafts are rotatably coupled to one another when said first output shaft overruns said second output shaft by a predetermined amount. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A transfer case for dividing torque to front and rear axles of a vehicle, said transfer case comprising:
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an input shaft coupled to a vehicle transmission to be rotatably driven thereby; a first output shaft to transmit torque to a first axle of the vehicle; a second output shaft to transmit torque to a second axle of the vehicle; an interaxle differential disposed between said input shaft and said first and second output shafts for transmitting torque from said input shaft to said first and second output shafts, and allowing said first and second output shafts to rotate differentially with respect to one another; a first one-way clutch to selectively lock said interaxle differential when said second output shaft overruns said first output shaft by a predetermined amount; and a second one-way clutch to selectively lock said interaxle differential when said first output shaft overruns said second output shaft by a predetermined amount. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A transfer case for dividing torque to front and rear axles of a vehicle, said transfer case comprising:
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a transfer case housing; an input shaft rotationally supported in said housing and coupled to a vehicle transmission to be rotatably driven thereby; a front output shaft to transmit torque to a front axle of the vehicle; a rear output shaft to transmit torque to a rear axle of the vehicle; an interaxle differential disposed between said input shaft and said front and rear output shafts for transmitting torque from said input shaft to said front and rear output shafts, and allowing said first and second output shafts to rotate differentially with respect to one another; at least a first bi-directional one-way clutch disposed between said rear output shaft and said front output shaft to selectively lock said interaxle differential when said rear output shaft tends to overrun said front output shaft to restrict such overunning by engagement of said at least first clutch. - View Dependent Claims (18, 19, 20, 21, 27)
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22. A transfer case for dividing torque to front and rear axles of a vehicle, said transfer case comprising:
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a housing; an input shaft supported in said housing and coupled to a vehicle transmission to be rotatably driven thereby; a front output shaft to transmit torque to a front axle of the vehicle; a rear output shaft to transmit torque to a rear axle of the vehicle; an interaxle differential disposed between said input shaft and said front and rear output shafts for transmitting torque from said input shaft to said front and rear output shafts, and allowing said first and second output shafts to rotate differentially with respect to one another; at least a first bi-directional one-way clutch disposed between said rear output shaft and said front output shaft to selectively lock said interaxle differential when said rear output shaft tends to overrun said front output shall to restrict such overunning by engagement of said at least first clutch. - View Dependent Claims (23, 24, 25, 26)
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Specification