Abstract: A four-wheel drive vehicle has an engine output shaft; a transmission having an input shaft connected to the output shaft and an output shaft connected through a transmission mechanism to the input shaft; a drive gear meshed with an output gear connected to the output shaft of the transmission; a front wheel side power transmitting mechanism; a rear wheel side power transmitting mechanism; a center differential mechanism coaxial with the drive gear and having an input member connected to the drive gear, a first output member connected to the front wheel side power transmitting mechanism, and a second output member connected to the rear wheel side power transmitting mechanism; a front differential gear coaxial with the center differential mechanism and connected to the first output member of the center differential mechanism; a power converting gear mechanism for converting a rotation about a first axis to a rotation about a second axis being perpendicular to the first axis to transmit power to the rear side p

Abstract: A power transmission device for four wheel drive vehicle includes a differential motion limiting device, for limiting differential motion of a center differential device, which is made up by a wet-type frictional clutch and a hydraulic actuator. Under running condition, the frictional clutch is engaged by certain engaging force, and considering frictional coefficient of roads, the clutch is engaged with some slips so that torque distribution to front and rear wheels becomes even (50:50), then torque is distributed from the center differential device to front and rear wheels. The line pressure is applied to the hydraulic actuator through a regulator valve. In normal running condition, the regulator valve reduces the line pressure pre certain ratio, the reduced pressure is applied to the hydraulic actuator. In the case the manual valve being shifted to R range or low speed position, the regulator valve is switched to apply the line pressure directly to the hydraulic actuator.

Abstract: A four-wheel drive vehicle has a front wheel side having a front wheel set, a rear wheel side having a rear wheel set, an engine having an output shaft extending in a transverse direction of a vehicular body, a transmission having an input shaft connected to the output shaft of the engine and an output shaft connected through a transmission mechanism to the input shaft such as to extend in a transverse direction of the vehicular body, a rotating member connected to the output shaft of the transmission, a front differential gear, a first output member connected between the rotating member and one of the wheel sets for transmitting power to one of the wheel sets through the front differential gear, a second output member coaxial with the first output member, a rear wheel propeller mechanism between the second output member and the other wheel set, and operative to convert the rotation of the second output member into rotation about an axis perpendicular to the axis of rotation of the second output member for dr

Abstract: Provided is a power transmission device for four-wheel drive vehicles of both the full-time type and part-time types, wherein a wet multiple-disc clutch is mounted in a ring gear covering the front-wheel differential gear and arranged coaxially with the differential gear. The wet multiple-disc type clutch is engaged by means of a hydraulic actuator in which a plurality of pistons are arranged in series. Hydraulic pressure is fed into oil chambers formed by the pistons through individual or common oil passages. The wet multiple-clutch constitutes a differential motion limiting device for stopping or limiting the differential motion of a center differential gear for the full-time four wheel drive, or constitutes a rear wheel drive switching unit for engaging and disengaging the power transmission between the ring gear mount casing and the transfer unit.

Abstract: A power transmission device for a full-time four wheel drive vehicle has a differential motion limiting device composed of a hydraulic frictional clutch such as a wet multiple disc type clutch. The friction clutch is disposed between a diff-carrier constituting a front wheel differential gear and a ring gear mount casing covering the diff-carrier and arranged coaxially with the diff-carrier. The ring gear mount casing is associated with the diff-carrier in a center differential gear, and the diff-carrier of the front wheel differential gear is associated with the left hand side gear in the center differential gear. Thus, when the friction clutch is engaged, the ring gear mount casing and the diff-carrier of the front wheel differential gear are integrally coupled with each other so that the rotation of the ring gear is transmitted directly to the front wheel differential gear, while the two elements in the center differential gear are integrally coupled with each other to lock the center differential gear.

Abstract: A four-wheel drive vehicle has a front wheel side having a front wheel set, a rear wheel side having a rear wheel set, an engine having an output shaft extending in a transverse direction of a vehicular body, a transmission having an input shaft connected to the output shaft of the engine and an output shaft connected through a transmission mechanism to the input shaft such as to extend in a transverse direction of the vehicular body, a rotating member connected to the output shaft of the transmission, a front differential gear, a first output member connected between the rotating member and one of the wheel sets for transmitting power to one of the wheel sets through the front differential gear, a second output member coaxial with the first output member, a rear wheel propeller mechanism between the second output member and the other wheel set, and operative to convert the rotation of the second output member into rotation about an axis perpendicular to the axis of rotation of the second output member for dr

Abstract: A four-wheel drive vehicle has an engine output shaft; a transmission having an input shaft connected to the output shaft and an output shaft connected through a transmission mechanism to the input shaft; a drive gear meshed with an output gear connected to the output shaft of the transmission; a front wheel side power transmitting mechanism; a rear wheel side power transmitting mechanism; a center differential mechanism coaxial with the drive gear and having an input member connected to the drive gear, a first output member connected to the front wheel side power transmitting mechanism, and a second output member connected to the rear wheel side power transmitting mechanism; a front differential gear coaxial with the center differential mechanism and connected to the first output member of the center differential mechanism; a power converting gear mechanism for converting a rotation about a first axis to a rotation about a second axis being perpendicular to the first axis to transmit power to the rear side p

Abstract: A center differential gear adapted for use in a power transmission device for full-time type four-wheel drive vehicles includes a diff-carrier coupled with a power transmitting front casing covering the front diff-carrier of a front-wheel differential gear and arranged coaxially with the diff-carrier, a side gear coupled to the front wheels, and another side gear coupled to a gear mount casing which transmits power to the rear wheels. The diff-carrier of the center differential gear is supported between the side gear on the side driving the front-wheel differential gear and the gear mount casing in cantilever fasion. The other side gear is spline-coupled directly to the gear mount casing without passing through the diff-carrier.

Abstract: A four wheel drive automatic transmission, comprising: a speed-changing transmission unit; a front wheel transmission mechanism driven by the transmission unit and having a large driving gear and bearings for the large driving gear; a center differential unit having an input member driven by the large driving gear and two output members for driving front wheels and for driving rear wheels, respectively; a transfer with a rear wheel driving transmission having a driving gear member disposed coaxially with the output member for rear wheel driving, a connecting member between the output member for rear wheel driving and the driving gear member and a transfer output gear member driven by the driving gear member; a case in which the front wheel transmission mechanism, the center differential unit and the transfer are disposed; and, an oil separating structure defining separately lubricatable cavities within the case, the structure comprising two seal members, disposed between the connecting member and the case at

Abstract: A one-way clutch biasing means for an automatic transmission, comprising: an inner spline formed on a one-way clutch retaining member; an outer spline formed on the outer race of the one-way clutch and loosely meshed with the inner spline; and a resilient member fitted between a side wall surface of the inner spline of the retaining member and an opposing side wall surface of the outer spline of the outer race to urge the outer race constantly in the locking direction of the one-way clutch.