A lubrication system (400) for a transfer case (200) includes a pump (228) selectively supplying a working fluid to a fluid reservoir of an actuator (226) configured to apply force to a clutch assembly (214) to cause the clutch assembly (214) to move between a disengaged position and an engaged position. The lubrication system also includes a relief valve (302) having a relief valve inlet fluidly coupled to the fluid reservoir of the actuator (226) which opens to receive the working fluid based on a threshold pressure level of the working fluid in the fluid reservoir. The lubrication system also includes a trough (306) fluidly coupled to a relief valve outlet of the relief valve (302). The trough (306) carries the working fluid from the relief valve outlet to a bearing assembly (227) associated with at least one of an input shaft (204) and a primary output shaft (206) of the transfer case (200) when the clutch assembly (214) is in the disengaged position.

A device is provided which performs highly-accurate control in low-torque regions while taking advantage of hydraulic pressure sealed-type hydraulic control devices. The device includes: a first characteristic (sealed pressurization) obtained by closing the on/off valve and driving an oil pump: a second characteristic (sealed depressurization) obtained by disabling drive of the oil pump and opening the on/off valve; and a third characteristic (flow-rate control) obtained by opening the on/off valve and driving the oil pump. In the process of supplying hydraulic pressure to a piston chamber in a low torque region, the device performs control according to the third characteristic. In the process of pressurizing the piston chamber in a torque region higher than the low torque region, the device performs control according to the first characteristic. In the subsequent process of depressurizing the piston chamber, the device performs control according to the second characteristic.

An automotive vehicle axle and, more specifically, a transmission shaft on an automotive vehicle that can be connected and disconnected in order to allow selection of driving power for the vehicle. The shaft connection includes a first shaft segment; a second shaft segment; and a connector linking the first shaft segment to the second shaft segment. The connector selectively connects or disconnects the first shaft segment to the second shaft segment.

An arrangement of a vehicle is provided having normal transverse engine/transmission normal two-wheel drive operation which can be selectively placed into four-wheel drive operation wherein a pump which powers the coupling or uncoupling is independent of the transmission lubrication pump and is powered by the transmission.

A differential assembly is disclosed, including a housing forming an interior space, and a shaft may extend into a portion of the interior space of the housing. A side gear including an aperture may be arranged within the interior space and an end portion of the shaft is aligned and extends through the aperture. The differential assembly may further include a sliding sleeve configured with a flat flange portion, the sliding sleeve may extend through the aperture and slide over the end portion of the shaft. Furthermore, a pinion gear may be configured with a flat face portion and a pinion gear cam portion may be configured to extend axially away from the flat face portion of the pinion gear. An actuator may actuate the sliding sleeve between a sleeve first position and a sleeve second position and the flat flange portion may interact with the pinion gear cam portion.

A device is disclosed that performs highly accurate control in a low-torque region and improves the response of the hydraulic system, taking advantage of hydraulic sealed-type hydraulic control devices. The hydraulic sealed-type hydraulic control device includes: a first characteristic (sealed pressurization) obtained by closing an on-off valve and driving an oil pump; a second characteristic (sealed depressurization) obtained by disabling drive of the oil pump and opening the on-off valve; and a third characteristic (flow-rate control) obtained by opening the on-off valve and driving the oil pump. In a low-torque region, the device performs control according to the third characteristic. In a high-torque region, the device performs control according to the second characteristic. In the process of depressurization, the device performs control according to the second characteristic. Moreover, the device performs control to increase commanded hydraulic pressure in immediate response to an accelerator's change amount larger than a predetermined value.

A control apparatus for a four-wheel drive vehicle includes a current detector configured to output a detection signal in accordance with the magnitude of an actual control current, a target current value calculator configured to calculate a target current value that is a target value of the control current, and a current controller configured to control a current output circuit to output the control current having the target current value calculated by the target current value calculator based on a result of detection performed by the current detector. When the four-wheel drive vehicle is in a two-wheel drive mode in which first and second friction clutches are released, the current controller performs zero-point adjustment for adjusting a zero point of the control current to be output from the current output circuit.

For the operation of a gearless clutch-controlled differential unit with a first clutch and a second clutch, without abandoning the possibility of assigning different torques to the clutches, it is provided that a control variable originally generated by a control variable unit is supplied to the first clutch unchanged while the control variable is supplied to the second clutch subject to the intermediate connection of an individual control element. The first and second clutches have clutch characteristics that are distinct from one another.

A clutched device can include a differential and first and second conduits. The differential can transmit differential power to first and second outputs. Clutch plates can rotate through a clutch cavity and transmit power between the second output and a third output. An outer carrier and an inner carrier can be coupled for rotation with the second and third outputs, respectively. The first conduit can be open to a first peripheral region of the clutch cavity and fluidly couples the first region to a cavity separate from the clutch cavity. The second conduit can be open to a second peripheral region that is circumferentially spaced apart from the first region. The second conduit can fluidly couple the second region to a central region of the clutch cavity. Rotation of the outer carrier in opposite rotational directions slings lubricant to the first and second conduits, respectively.

A device is disclosed that performs highly accurate control in a low-torque region and improves the response of the hydraulic system, taking advantage of hydraulic sealed-type hydraulic control devices. The hydraulic sealed-type hydraulic control device includes: a first characteristic (sealed pressurization) obtained by closing an on-off valve and driving an oil pump; a second characteristic (sealed depressurization) obtained by disabling drive of the oil pump and opening the on-off valve; and a third characteristic (flow-rate control) obtained by opening the on-off valve and driving the oil pump. In a low-torque region, the device performs control according to the third characteristic. In a high-torque region, the device performs control according to the second characteristic. In the process of depressurization, the device performs control according to the second characteristic. Moreover, the device performs control to increase commanded hydraulic pressure in immediate response to an accelerator's change amount larger than a predetermined value.