Abstract: A driving force transmission apparatus includes a linkage mechanism that is able to carry out switchover between a connected state where a first intermediate shaft and a second intermediate shaft are connected to each other so as to be non-rotatable relative to each other to transmit torque output from an electric motor to a rear wheel, and a disconnected state where the first intermediate shaft and the second intermediate shaft are disconnected from each other. A control unit reduces the torque that is generated by the electric motor, after making a rotational speed of the first intermediate shaft higher than or equal to a rotational speed of the second intermediate shaft, and then switches the driving force transmission apparatus from the disconnected state to the connected state by controlling the linkage mechanism with the torque that is generated by the motor maintained at a reduced level.

Abstract: A speed reduction mechanism includes a bearing mechanism arranged on an axis of an output mechanism and including ball bearings that are arranged in parallel with each other in an axial direction of a differential case. The differential case is rotatably supported by the ball bearings of the bearing mechanism such that the entirety of an outer periphery of one of the ball bearings faces an inner periphery of a first housing element that accommodates the differential case and that is made of a material having a stiffness lower than a stiffness of a material of a rotation force applying member, and the entirety of an outer periphery of the other one of the ball bearings faces an inner periphery of the rotation force applying member.

Abstract: A motor driving force transmission device including a speed reduction and transmission mechanism which transmits a motor driving force to a rear differential, a first electric motor that is connected to the rear differential via the speed reduction and transmission mechanism and which produces a first motor driving force, a second electric motor that is connected to the first electric motor and the speed reduction and transmission mechanism and which produces a second motor driving force, and an ECU. The ECU outputs a control signal to drive both the first electric motor and the second electric motor when a driving torque required for the rear differential is equal to or larger than a predetermined torque, and outputs a control signal to drive alternately the first electric motor and the second electric motor when the driving torque required for the rear differential is smaller than the predetermined torque.

Abstract: A motor driving force transmission device includes electric motors which produce motor driving force with which a rear differential is operated and a speed reduction and transmission mechanism which reduces the speed of the motor driving force of the electric motors and transmits it to the rear differential. The speed reduction and transmission mechanism has eccentric cams which rotate as the electric motors are driven, transmission members which rotate as the eccentric cams rotate, and is disposed on an outer circumference of the rear differential.

Abstract: In a motor driving force transmission apparatus, a cam mechanism includes an input cam member that rotates upon reception of motor torque from a cam actuating electric motor and an output cam member that outputs cam thrust force through movement due to rotation of the input cam member, and rotation of the output cam member around an axis of a housing is restricted by a restricting member fixed to the housing.

Abstract: In a reduction-transmission mechanism, an input member is arranged at such a position that a size obtained by adding a fitting clearance formed between a ball bearing and an outer periphery of an eccentric portion, a fitting clearance formed between the ball bearing and an inner periphery of the input member, which defines a center hole, and a radial internal clearance of the ball bearing is smaller than a size obtained by adding a fitting clearance formed between an outer periphery of each of a plurality of output members and a corresponding one of needle roller bearings, a fitting clearance formed between each of the needle roller bearings and an inner periphery of the input member, which defines a corresponding one of a plurality of pin insertion holes, and a radial internal clearance of each of the needle roller bearings.

Abstract: A cage of each of ball bearings arranged on respective outer peripheries of eccentric portions of a motor shaft has an annular base portion interposed between an inner ring and an outer ring and a plurality of partition wall portions for forming pockets together with the base portion. In a first ball bearing, part of the base portion protrudes axially outward from the inner raceway and forms an oil receiving portion that receives lubricating oil from the second rolling bearing side, at a portion around the rotation axis and axially outward of the first rolling bearing.

Abstract: A reduction-transmission mechanism includes: an input member formed of an external gear that makes circular motion with an eccentric amount; a rotation force applying member formed of an internal gear that is in mesh with the input member; and output members that receive and output rotation force applied to the input member by the rotation force applying member, and that are passed through the respective pin insertion holes. Each of the output members is provided with a needle roller bearing at a portion that is able to contact an inner periphery, which defines a corresponding one of the through-holes, and the input member has third oil supply passages that extend from the center hole to the pin insertion holes, and lubricating oil is supplied to the needle roller bearings through the third oil supply passages by centrifugal force generated in accordance with rotation of the motor shaft.

Abstract: A speed reduction mechanism includes: a speed reduction unit that includes an input member formed of an external gear that makes circular motion about a rotation axis with an eccentric amount, and a rotation force applying member formed of an internal gear that is in mesh with the input member; and a lubricating oil supply unit that supplies lubricating oil to a bearing of the speed reduction unit. The lubricating oil supply unit includes an oil tank arranged outside of the rotation force applying member, an oil delivery passage that delivers the lubricating oil to the oil tank, and a first oil introduction passage that introduces the lubricating oil from the oil tank to the bearing. The lubricating oil is delivered to the oil delivery passage through pumping action of the input member based on the circular motion.