Abstract: A drive force transmission device includes a first direction one-way clutch, a second direction one-way clutch, a second direction rotation transmission clutch, a cam mechanism and a regulating member. The first direction one-way clutch and the second direction one-way clutch are arranged to connect first and second force transmission paths between an input shaft and an output shaft to transmit rotation in first and second rotational directions, respectively. The second direction rotation transmission clutch is arranged to connect the second direction one-way clutch with the output shaft. The regulating member is coupled to the cam mechanism to regulate movement of the cam mechanism to maintain a disengaged state of the second direction rotation transmission clutch. The regulating member is arranged to be non-rotatable in response to rotation of the input shaft in the first rotational direction.

Abstract: A transfer mechanism distributes drive power from a drive power source of a motor vehicle to left and right front wheels and left and right rear wheels of the vehicle. A rear differential mechanism transfers the drive power to the left and right rear wheels. A clutch is provided between the rear differential mechanism and each of the left and right rear wheels. A control device independently controls an engaged state of each of the clutches. A speed-increasing mechanism sets revolution speeds of an output shaft of the transfer mechanism and of an input shaft of the rear differential mechanism to be the same and sets a speed of the outer circumference of the rear wheel to which the drive power is transferred, via an engaged clutch, to be faster than a speed of the outer circumference of the left and right front wheels.

Abstract: A drive force transmission device includes a first direction one-way clutch, a second direction one-way clutch, a second direction rotation transmission clutch, a cam mechanism and a regulating member. The first direction one-way clutch and the second direction one-way clutch are arranged to connect first and second force transmission paths between an input shaft and an output shaft to transmit rotation in first and second rotational directions, respectively. The second direction rotation transmission clutch is arranged to connect the second direction one-way clutch with the output shaft. The regulating member is coupled to the cam mechanism to regulate movement of the cam mechanism to maintain a disengaged state of the second direction rotation transmission clutch. The regulating member is arranged to be non-rotatable in response to rotation of the input shaft in the first rotational direction.

Abstract: A transfer mechanism distributes drive power from a drive power source of a motor vehicle to left and right front wheels and left and right rear wheels of the vehicle. A rear differential mechanism transfers the drive power to the left and right rear wheels. A clutch is provided between the rear differential mechanism and each of the left and right rear wheels. A control device independently controls an engaged state of each of the clutches. A speed-increasing mechanism sets revolution speeds of an output shaft of the transfer mechanism and of an input shaft of the rear differential mechanism to be the same and sets a speed of the outer circumference of the rear wheel to which the drive power is transferred, via an engaged clutch, to be faster than a speed of the outer circumference of the left and right front wheels.

Abstract: A first casing structure defines an atmospheric chamber between a transfer and a transmission. A second casing structure defines a transfer chamber containing a transfer mechanism of the transfer, and further defines a connecting passage through which the transfer chamber is connected to the atmospheric chamber. A gas-liquid separating device is interposed between the transfer chamber and the connecting passage so that the transfer chamber and the connecting passage are connected through the gas-liquid separating device.

Abstract: The present invention provides an apparatus for estimating clutch temperature estimates clutch temperatures that closely follow actual clutch temperature without a temperature sensor and at low cost. The apparatus employs method for calculating energy applied to the driving clutch according to the detected rotational speed difference and estimated torque and method for estimating a clutch temperature variation based on the calculated energy and estimating a clutch temperature based on the estimated clutch temperature variation.

Abstract: The present invention provides an apparatus for estimating clutch temperature estimates clutch temperatures that closely follow actual clutch temperature without a temperature sensor and at low cost. The apparatus employs method for calculating energy applied to the driving clutch according to the detected rotational speed difference and estimated torque and method for estimating a clutch temperature variation based on the calculated energy and estimating a clutch temperature based on the estimated clutch temperature variation.

Abstract: A first casing structure defines an atmospheric chamber between a transfer and a transmission. A second casing structure defines a transfer chamber containing a transfer mechanism of the transfer, and further defines a connecting passage through which the transfer chamber is connected to the atmospheric chamber. A gas-liquid separating device is interposed between the transfer chamber and the connecting passage so that the transfer chamber and the connecting passage are connected through the gas-liquid separating device.

Abstract: To achieve a first object of the present invention, a starting time limit vehicle speed which preferentially permits a torque distribution to front and rear wheels at the time of starting of a vehicle is switched in accordance with a degree of a diameter difference. To achieve a second object of the present invention, when the vehicle makes a normal running with different-diameter tires mounted thereon, a front/rear wheel distribution torque caused by a front/rear wheel rotation speed difference owing to the different-diameter tires is limited by switching a torque gain depending on a degree of a diameter difference.

Abstract: A limiter plug and a drain plug are juxtaposed in a valve block. The limiter plug is provided with a thermo-switch of which operation, when a predetermined temperature is reached, opens a communication passage for drainage by means of a limiter pin. The drain plug is provided with a drain pin for draining a high-pressure oil in conjunction with the drainage action of the limit pin induced by the thermo-switch so that, when the predetermined temperature is reached, it substantially nullifies the torque for switching from 4 wheel-drive to 2 wheel-drive. In the status of no operation of the thermo-switch, the drain pin when a predetermined torque is reached, gradually opens the drain hole while catching a balance, to limit the torque to a predetermined value.

Abstract: A valve block coupled to a rotor is provided with a drain mechanism that includes a drain pin adapted to open and close a drain hole. The drain pin is incorporated in a drain plug by providing a support by a return spring. The drain pin has an orifice for generating a flow resistance. One end turn portion of the return spring is press fitted into the interior of the drain pin having the orifice, while the other end turn portion of the return spring is press fitted into the interior of a limiter plug having a limiter pin, whereby the drain pin is rotationally positioned to alleviate cavitation noises.

Abstract: A torque varying mechanism comprises an accommodation hole that has a relief hole formed in its bottom and that receives a check ball therein. The accommodation hole is configured so as to present a relationship in which the area of flow passage between the accommodation hole and the check ball increases linearly as a function of the amount of displacement of the check ball after opening of the relief hole, after which the flow passage area keeps a unvarying value. A hysteresis characteristic is imposed on a switching point where switching is made between a high torque transmission characteristic and a low torque transmission characteristic relative to an increase and a decrease of the vehicle velocity.

Abstract: To achieve a first object of the present invention, a starting time limit vehicle speed which preferentially permits a torque distribution to front and rear wheels at the time of starting of a vehicle is switched in accordance with a degree of a diameter difference. To achieve a second object of the present invention, when the vehicle makes a normal running with different-diameter tires mounted thereon, a front/rear wheel distribution torque caused by a front/rear wheel rotation speed difference owing to the different-diameter tires is limited by switching a torque gain depending on a degree of a diameter difference.

Abstract: A joint includes therein a valve serving to cut off torque transmitted from a front wheel associated driving shaft to a rear wheel associated driven shaft by the action of a weight based on a centrifugal force when a predetermined number of rotations is reached. The valve is coupled to a rotor or a housing connected to the driven shaft so that the rotations of the valves are in synchronism with rotations of the driven shaft. For this reason, the number of rotations of the valve is determined by the number of rotations of the rear wheel associated with the driven shaft, allowing the torque to be cut off depending on the vehicle velocity.

Abstract: A drain plug is disposed in a drain hole through which oil is discharged from a high-pressure chamber formed in a valve block. Within the drain plug there is arranged a drain pin that slidably opens and closes the drain hole. A fixed pin serves to restrict a displacement of the drain pin. A thermo-switch is located within a low-pressure chamber behind the drain pin in such a manner as to be urged by a return spring so that the drain pin is pressed to keep the drain hole closed. When a predetermined temperature is reached, the thermo-switch allows its head pin to extend, with the reaction force as a result of abutment of the head pin against the fixed pin causing the thermo-switch to retreat to release the pressing force exerted on the drain pin. In consequence, the drain pin is displaced by a high pressure toward the direction in which the drain hole is opened, allowing high-pressure oil to be drained into the low pressure side.

Abstract: An axially extending extension is formed on a bearing retainer provided adjacent to a valve block of a joint and press-fitted into the interior of a housing. The extension has at its outer peripheral end a bearing by way of which the bearing retainer is rotatably supported by a differential gear case located outside thereof. This allows moment arising from rotational secondary torque received by the housing to be transmitted from the bearing retainer extension via the bearing to the outside differential gear case, thereby preventing the moment from acting on a main shaft which is a centrally located output shaft.

Abstract: A torque characteristic shifting mechanism is provided in an accommodation hole of a rotary valve. The torque characteristic shifting mechanism changes over the torque characteristics in a multi-step manner with an increase of the vehicle velocity by setting the distances so as to meet the relationships R3≈R2>R1 or R2>R3>R1 where R1, R2 and R3 are the distance from a center of rotation of a weight member accommodated rockably around the center of rotation to a center of the ball blocking the drain hole, the distance from the center of rotation to a center of gravity of the weight member and the distance from the center of rotation to a center of a spring, respectively.

Abstract: A plunger is accommodated in each of a plurality of plunger chambers formed axially in a rotor, with the plunger being displaced by rotation of a cam face associated with a housing. A first one way valve for intake is incorporated in the head of each plunger and a second one way valve for discharge is disposed within in a discharge hole leading to the plunger chambers. The intake stroke of the plunger caused by rotation of the cam opens the first one way valve to suck oil from a low pressure chamber into the plunger chamber. The discharge stroke of the plunger opens the second one way valve to allow the discharged oil to flow through the orifice into the low pressure chamber, whereby a torque corresponding to the relative rotational-speed difference is transmitted from the housing side to the rotor side.

Abstract: A lubrication apparatus in a vehicular power transmission unit includes device pinion shaft which is rotatably supported by a bearing disposed at a rear end portion of a casing. The casing contains lubricating fluid. A pickup member is disposed on the drive pinion shaft and picks up lubricating fluid upon rotation of the drive pinion shaft. A trough is formed on a wall of the casing in an inclined relation to the axis of the drive pinion shaft. The trough receives the lubricating fluid which is picked up and allows the lubricating fluid to flow under the influence of gravity to the rear end portion of the casing for lubricating the bearing located thereof.

Abstract: A transfer case of a driving power transfer apparatus is connected to a transverse engine through a transmission in an automotive vehicle. The transfer case has a case body which includes a cylindrical portion, an opening portion connected to an end of the cylindrical portion and a bolt connecting portion formed around the opening portion. The opening portion is connected to the cylindrical portion in offset connection such that a part of the bolt connecting portion is overlapped with the cylindrical portion as viewed from the axis of the opening portion. An adapter is connected to the bolt connecting portion by means of bolts and has a cylindrical engaged portion which is sealingly engaged with the first opening portion of the case body. Therefore, a clearance between the transfer case and the engine is sufficiently ensured to improve the degree of freedom in the layout of the engine.