Power transfer mechanism for 4WD vehicles with low effort mode shift system

摘要

A power transfer mechanism for a four-wheel drive vehicle includes a first shaft for transferring torque to a first driveline, a second shaft for transferring torque to a second driveline, and a transfer mechanism driving the second shaft. A mode clutch drivingly connects the first shaft to the transfer mechanism and includes a clutch gear-driven by the transfer mechanism and a mode sleeve. A sprocket associated with the transfer mechanism has internal spline teeth meshed with external spline teeth on the second shaft with a predetermined amount of backlash therebetween. A ball cam mechanism centers the backlash and permits relative rotation of the transfer mechanism and the mode sleeve to circumvent a blocked mode shift.

主权项

1. A power transfer mechanism for a four-wheel drive vehicle having a powertrain, a first driveline for driving a pair of first wheels and a second driveline for driving a pair of second wheels, the power transfer mechanism comprising:
a first shaft adapted to transmit drive torque from the powertrain to the first driveline; a second shaft adapted to be coupled to the second driveline; a transfer mechanism including a first transfer component rotatably mounted on the first shaft, a second transfer component mounted on the second shaft, and a torque transmission component interconnecting the first and second transfer components; a mode clutch for selectively coupling the first transfer component for driven rotation with the first shaft, the mode clutch including a clutch gear fixed to the first transfer component and having clutch gear teeth, and a mode sleeve fixed via a sliding spline connection for rotation with the first shaft and having mode sleeve teeth, wherein the mode sleeve is operable in a released position to disengage the mode sleeve teeth from the clutch gear teeth for releasing the transfer mechanism from driven connection with the first shaft, and wherein the mode sleeve is operable in an engaged position to engage the mode sleeve teeth with the clutch gear teeth for coupling the transfer mechanism for driven connection with the first shaft; and a backlash interface connection disposed between the second transfer component and the second shaft to permit a predetermined amount of angular movement therebetween so as to reduce an axial force required to move the mode sleeve from the released position into the engaged position, the backlash interface connection including external shaft spline teeth formed on the second shaft, a plurality of recesses formed between certain adjacent pairs of the external shaft spline teeth with a retention chamber formed in each recess, internal spline teeth formed in a central aperture of the second transfer component and which are interdigitated with the external shaft spline teeth, a plurality of ramped cam seats formed between adjacent pairs of the internal spline teeth and which are aligned with respect to the plurality of recesses, and a plurality of spring-biased cam followers at least partially disposed in each of the retention chambers and biased into engagement with a corresponding one of the ramped cam seats so as to establish a predefined amount of angular clearance between each set of interdigitated shaft spline teeth and internal spline teeth to define a predetermined amount of backlash between the second transfer component and the second shaft; wherein the second transfer component is rotatable through the backlash to align the clutch gear teeth with the mode sleeve teeth to circumvent a blocked movement of the mode sleeve from the released position into the engaged position.