Toyota Jidosha Kabushiki Kaisha

Hideyuki Iwata

Masaki Inui

Hideo Hamano

Masahiko Noba

Keiji Takeshita

Hisashi Fukuchi

In a part-time four-wheel drive vehicle, and electric control apparatus for a transfer device in drive connection to a front or rear differential is arranged to permit selection of the four-wheel drive mode at the transfer device during travel of the vehicle in the two-wheel drive mode only in a condition where travel speed of the vehicle and temperature of lubricating oil in the differential are in a predetermined allowable region. The allowable region is defined to permit engagement of a clutch mechanism in the transfer drive mode without causing any heavy load acting thereon.

Electric control apparatus for transfer device in part-time four-wheel

In a part-time four-wheel drive vehicle equipped with a transfer device adapted to change the operating mode of the vehicle drive system from a two-wheel drive mode to a four-wheel drive mode in response to engagement of a hydraulically operated clutch mechanism provided therein and with a split axle drive mechanism in the form of a differential which includes a clutch mechanism disengageable for disconnecting a pair of side shafts of the differential from a set of non-driven split axle parts when the two-wheel drive mode is selected at the transfer device and engageable for connecting the side shafts to the non-driven split axle parts when the four-wheel drive mode is selected at the transfer device, a control system for the split axle drive mechanism includes a pressure switch arranged to detect a hydraulic pressure applied to the clutch mechanism of the transfer device to be operated when applied with a predetermined hydraulic pressure after engagement of the clutch mechanism of the transfer device and an actuator arranged to effect engagement of the clutch mechanism of the differential in response to operation of the pressure switch and to disengage the clutch mechanism of the differential when the pressure switch is rendered inoperative.

Control system for split axle drive mechanism in part-time four-wheel

A split axle drive mechanism for a part-time four-wheel drive vehicle comprises a fist axle shaft connected to one side gear of a differential, a first output member arranged to be connected to the first axle shaft, a second axle shaft axially slidably connected to the other side gear, a second output member arranged to be connected to the second axle shaft, a clutch mechanism disengageable for disconnecting the first axle shaft from the first output member when the vehicle is in a two-wheel drive mode and engageable for connecting the first axle shaft to the first output member when the vehicle is in a four-wheel drive mode, a connecting rod axially slidably disposed in the axle shafts and having one end operatively connected with the clutch mechanism and another end connected with the second axle shaft, a coupling mechanism for connecting the second axle shaft to the second output member in response to engagement of the clutch mechanism, and a shift mechanism arranged to axially translate a clutch sleeve of the clutch mechanism between disengaged and engaged positions. A pneumatic actuator is arranged to operate the shift mechanism, and the coupling mechanism is arranged to connect the second axle shaft to the second output member after engagement of the clutch mechanism under control of the pneumatic actuator.

Split axle drive mechanism for part-time four-wheel drive vehicle

A transmission unit comprises a differential gear unit having a pair of side-journals rotatably supported by a pair of axially spaced side-bearings carried on a pair of carrier portions of a casing for the transmission unit, a pair of wheel axles extending outwardly through the respective side-journals from the differential gear unit in an opposite direction and surrounded by a pair of annular seal members carried on the respective carrier portions, a pair of annular shim plates interposed between each of the carrier portions and each of the side-bearings, and a pair of oil passages for leading lubricating oil into a pair of annular side-spaces formed around each of the wheel axles between the respective side-bearings and the respective seal members. Each of the annular shim plates is formed at the inner peripheral portion thereof with a number of circumferentially spaced radial projections and recesses which are arranged to radially lead the lubricating oil onto each of the wheel axles for lubrication of the side-journals.

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Toyota, Japan

Hideyuki Iwata