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 telescopic shaft includes an inner shaft and a cylindrical outer shaft that are fitted together. A first raceway groove extending in the axial direction is formed in an outer peripheral surface of the inner shaft. A second raceway groove extending in the axial direction and facing the first raceway groove is formed in an inner peripheral surface of the outer shaft. A plurality of balls interposed between the first and second raceway grooves and arranged in a row in the axial direction roll in a first stroke range in the axial direction with respect to the inner shaft and roll in a second stroke range in the axial direction with respect to the outer shaft as the inner and outer shafts move relative to each other in the axial direction. The depth of the first raceway groove decreases from the middle toward both ends of the first stroke range.

Abstract: In an in-wheel motor driving device, since an involute speed reduction gear with a small difference in number of teeth which can be made small in size can be disposed on an inner side of an inner rotor type motor, a size of the in-wheel motor driving device in the direction of a rotational axis can be reduced. Further, in the inner rotor type motor, since a first stator is disposed so as to face a radially outer side of a large-diameter rotor, heat generated in the first stator is easily dissipated. On the other hand, in an outer rotor type motor, since a second stator is disposed so as to face a radially inner side of a small-diameter rotor, a torque radius of the small-diameter rotor can be made large, thereby making it possible to ensure a large torque capacity. Because of this, the outer rotor type motor can be made smaller in diameter than the inner rotor type motor, thereby making it possible to ensure a large space within a wheel.

Abstract: When an outer ring is fitted to an inner periphery of an input member, which defines a center hole, and an inner ring is fitted to an eccentric portion with clearances in a reduction-transmission mechanism, in a state where tooth tips of the input member contact bottomlands of a rotation force applying member on a line perpendicular to a second axis and a fourth axis, a size between the second axis and a third axis is set to a size that is smaller than or equal to half of a size obtained by adding a diameter difference between an outside diameter of a ball bearing and an inside diameter of the input member, which defines the center hole, a diameter difference between an inside diameter of the ball bearing and an outside diameter of the eccentric portion and an operating clearance of the ball bearing.

Abstract: When a bearing includes outer and inner rings and the outer ring is fitted to the inner periphery of an input member, which defines a center hole, with a clearance and the inner ring is fitted to an eccentric portion with a clearance, a size between a second axis and a third axis is set to a size that is smaller than or equal to half of a size obtained by adding a diameter difference between an outside diameter of the bearing and an inside diameter of the input member, which defines the center hole, a diameter difference between an inside diameter of the bearing and an outside diameter of the eccentric portion and an operating clearance of the bearing in a state where the input member has been moved to contact the housing on a line perpendicular to the second axis and a fourth axis.

Abstract: A motor driving force transmission system includes an electric motor that generates motor torque for actuating a differential mechanism portion and outputs the motor torque, and that has a motor shaft with eccentric portions, and a bearing mechanism including a ball bearing interposed between one-side axial end portion of a housing and one-side axial end portion of a differential case, a ball bearing interposed between the other-side axial end portion of the differential case and one-side axial end portion of the motor shaft, and a ball bearing interposed between the other-side axial end portion of the housing and the other-side axial end portion of the motor shaft. An axial load is applied to the ball bearings of the bearing mechanism by a spring.

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 an in-wheel motor driving device, since an involute speed reduction gear with a small difference in number of teeth which can be made small in size can be disposed on an inner side of an inner rotor type motor, a size of the in-wheel motor driving device in the direction of a rotational axis can be reduced. Further, in the inner rotor type motor, since a first stator is disposed so as to face a radially outer side of a large-diameter rotor, heat generated in the first stator is easily dissipated. On the other hand, in an outer rotor type motor, since a second stator is disposed so as to face a radially inner side of a small-diameter rotor, a torque radius of the small-diameter rotor can be made large, thereby making it possible to ensure a large torque capacity. Because of this, the outer rotor type motor can be made smaller in diameter than the inner rotor type motor, thereby making it possible to ensure a large space within a wheel.

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 speed change gear device is provided with a housing, a first member supported rotatably about a predetermined rotational axis, a shaft member formed with an external gear, an annular member formed with an internal gear meshing with the external gear, and a transmission mechanism for transmitting a rotational component only of the annular member to the shaft member or a disc member arranged to be rotatable relative to the housing. The external gear differs from the internal gear in the number of teeth. Further, the first member is formed with a receiving hole that receives the annular member at a position where the center of the annular member is at a predetermined distance from the rotational axis. Then, the annular member is received in the receiving hole rotatably relative to the first member.

Abstract: The multi-stage reducer includes a first-stage reduction part to which the rotation from a motor is input and a second-stage reduction part to which the rotation having undergone speed reduction by the first-stage reduction part is input. The second-stage reduction part is disposed on an outer circumference of the first-stage reduction part.

Abstract: A speed change gear device is provided with a housing, a first member supported rotatably about a predetermined rotational axis, a shaft member formed with an external gear, an annular member formed with an internal gear meshing with the external gear, and a transmission mechanism for transmitting a rotational component only of the annular member to the shaft member or a disc member arranged to be rotatable relative to the housing. The external gear differs from the internal gear in the number of teeth. Further, the first member is formed with a receiving hole that receives the annular member at a position where the center of the annular member is at a predetermined distance from the rotational axis. Then, the annular member is received in the receiving hole rotatably relative to the first member.

Abstract: An easily structured swing internal contact type planetary gear device is proposed which can achieve a higher meshing ratio when an involute tooth profile is adapted. Each of an internal tooth of an internally toothed gear wheel and an external tooth of an externally toothed gear wheel is formed with an involute tooth profile. Under a driving condition, one of an internal tooth body of the internally toothed gear wheel and an external tooth body of the externally toothed gear wheel is elastically deformed in an extending direction and the other thereof is elastically deformed in a contracting direction so that the number of meshing teeth becomes larger than the number of meshing teeth under a non-driving condition.

Abstract: The multi-stage reducer includes a first-stage reduction part to which the rotation from a motor is input and a second-stage reduction part to which the rotation having undergone speed reduction by the first-stage reduction part is input. The second-stage reduction part is disposed on an outer circumference of the first-stage reduction part.

Abstract: An easily structured swing internal contact type planetary gear device is proposed which can achieve a higher meshing ratio when an involute tooth profile is adapted. Each of an internal tooth of an internally toothed gear wheel and an external tooth of an externally toothed gear wheel is formed with an involute tooth profile. Under a driving condition, one of an internal tooth body of the internally toothed gear wheel and an external tooth body of the externally toothed gear wheel is elastically deformed in an extending direction and the other thereof is elastically deformed in a contracting direction so that the number of meshing teeth becomes larger than the number of meshing teeth under a non-driving condition.

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 vehicle differential apparatus includes: a differential case; two side gears; and two pinions. An axial center of each pinion is provided with a first pinion shaft insertion hole. A pinion shaft is inserted in the first pinion shaft insertion holes. An inner peripheral surface of the first pinion shaft insertion hole of each pinion is provided with two sliding surfaces that are slidable on one of two pinion inner peripheral surface-supporting portions of the pinion shaft, and a non-contacting surface that is not able to contact the pinion inner peripheral surface-supporting portion. The sliding surfaces and the non-contacting surface of each first pinion shaft insertion hole are disposed at positions adjacent to each other in the axis direction of the first pinion shaft insertion hole.

Abstract: A gear pair includes a small-diameter conical involute gear having a conical angle, and a large-diameter conical involute gear having a conical angle. The small-diameter conical involute gear and the large-diameter conical involute gear are constituted by an aggregate of imaginary cylindrical gears.

Abstract: A speed change gear includes: a housing that has internal gears having different inside diameters; and a plurality of change gear units that are respectively in mesh with the plurality of internal gears and that change the speed of rotation from an input shaft to an output shaft. Each of the change gear units includes a rotating member that has one of a pin protruding in a direction along an input/output axis and an insertion hole; an eccentric member that centers on an eccentric axis that is eccentric with respect to the input/output axis; and an oscillating member that oscillatingly rotates as the eccentric member rotates about the input/output axis.