Abstract: A wet friction disc includes a friction surface and a lubrication groove through which a lubricant supplied to the friction surface flows. The lubrication groove has a plurality of circumferential groove portions that extends in a circumferential direction and a plurality of intersecting groove portions that extends in directions intersecting the circumferential direction. At least one of the circumferential groove portions has a through-hole that extends through the wet friction disc between an opposite surface facing s mating member and a surface on the opposite side in an axial direction.

Abstract: A wet friction disc includes a lubrication groove and a plurality of lands defined by the lubrication groove. The lubrication groove has a plurality of circumferential groove portions that extends in a circumferential direction and has a predetermined groove width in a radial direction, and a plurality of intersecting groove portions that extends in directions intersecting the circumferential direction. At least some of the circumferential groove portions have an arc shape such that an end in the circumferential direction is located adjacent to one of the lands in the circumferential direction and that the groove width is entirely contained within a range in the radial direction spanned by that land.

Abstract: A wet friction disc includes a friction surface and a lubrication groove through which a lubricant supplied to the friction surface flows. The lubrication groove has a plurality of circumferential groove portions that extends in a circumferential direction and a plurality of intersecting groove portions that extends in directions intersecting the circumferential direction. At least one of the circumferential groove portions has a through-hole that extends through the wet friction disc between an opposite surface facing s mating member and a surface on the opposite side in an axial direction.

Abstract: A wet friction disc includes a lubrication groove and a plurality of lands defined by the lubrication groove. The lubrication groove has a plurality of circumferential groove portions that extends in a circumferential direction and has a predetermined groove width in a radial direction, and a plurality of intersecting groove portions that extends in directions intersecting the circumferential direction. At least some of the circumferential groove portions have an arc shape such that an end in the circumferential direction is located adjacent to one of the lands in the circumferential direction and that the groove width is entirely contained within a range in the radial direction spanned by that land.

Abstract: An electromagnetic actuator includes an electromagnetic coil, a yoke serving as a magnetic path of a magnetic flux of the electromagnetic coil, an armature configured to move in an axial direction while being attracted by the yoke by energization of the electromagnetic coil, and a housing that houses the armature. The armature and the housing are coupled to each other by an engagement structure in which protrusions provided on one of the members engage with engagement grooves formed in the other one of the members. At least a part of the engagement groove is inclined with respect to the axial direction. When the armature moves while being attracted by the yoke, the protrusions of the armature slide along the engagement grooves of the housing, and the armature turns relative to the housing along the inclination of the engagement grooves.

Abstract: A connection-disconnection device configured to switch between a connected state and a released state of a side gear and a coupling shaft, each supported by a case member so as to be rotatable relative to the case member. The connection-disconnection device has an input shaft coupled to the side gear so as not to be rotatable relative to the side gear, axial movement of the input shaft being restricted with respect to the side gear, a dog member coupled to the coupling shaft so as not to be rotatable relative to the coupling shaft and so as to be movable with respect to the coupling shaft in an axial direction, and a moving mechanism configured to move the dog member back and forth in the axial direction. Each of the input shaft and the dog member has an annular meshing portion that mesh with each other.

Abstract: A driving force distributing apparatus is configured to distribute a driving force from an engine to right and left wheels in a manner that the driving force is differentially transmittable to the wheels and the transmission of the driving force is interruptible. The apparatus includes: a differential case; a differential gear mechanism including a pair of side gears and a plurality of pinion gears; an intermediate shaft coupled to one of the side gears such that the intermediate shaft is not rotatable relative to this side gear; and a clutch mechanism to transmit a driving force from the intermediate shaft to one of the wheels in a manner that the transmission of the driving force is interruptible. The clutch mechanism includes: coaxial relatively rotatable first and second rotational members; and a plurality of clutch plates disposed between the rotational members. The first rotational member is spline-fitted to the intermediate shaft.

Abstract: A driving-force distribution device is provided that can supply lubricant to an above-positioned pinion gear among a pair of pinion gears even when rotation of a differential case of a differential mechanism stops in a two-wheel-drive mode of a four-wheel-drive vehicle. A driving-force distribution device mounted on a four-wheel-drive vehicle includes a differential mechanism and a clutch mechanism. The differential mechanism includes a differential case, a pinion shaft, a pair of pinion gears, and a pair of side gears. In the pinion shaft, a flow passage is formed through which a lubricant is allowed to flow from the below-positioned pinion gear among the pair of pinion gears toward the above-positioned pinion gear in the two-wheel-drive mode in which the pair of pinion gears rotate in opposite directions with the differential case not rotating. The lubricant is supplied to the flow passage by rotation of the below-positioned pinion gear.

Abstract: An electromagnetic actuator includes an electromagnetic coil, a yoke serving as a magnetic path of a magnetic flux of the electromagnetic coil, an armature configured to move in an axial direction while being attracted by the yoke by energization of the electromagnetic coil, and a housing that houses the armature. The armature and the housing are coupled to each other by an engagement structure in which protrusions provided on one of the members engage with engagement grooves formed in the other one of the members. At least a part of the engagement groove is inclined with respect to the axial direction. When the armature moves while being attracted by the yoke, the protrusions of the armature slide along the engagement grooves of the housing, and the armature turns relative to the housing along the inclination of the engagement grooves.

Abstract: A driving force transmission apparatus includes: a pinion gear shaft having a pinion teeth portion, a first shaft portion extending from one side of the pinion teeth portion, and a second shaft portion extending from the other side of the pinion teeth portion; a ring gear meshing with the pinion teeth portion; a clutch housing capable of rotating relative to the pinion gear shaft on a rotation axis in coincidence with a rotation axis of the pinion gear shaft; a clutch mechanism located between the clutch housing and the first shaft portion of the pinion gear shaft; and a differential carrier accommodating the ring gear. The first shaft portion and the second shaft portion of the pinion gear shaft are supported by a first bearing and a second bearing, respectively. The clutch housing is supported by the pinion gear shaft through a third bearing fitted on the first shaft portion.

Abstract: A driving force distributing apparatus is configured to distribute a driving force from an engine to right and left wheels in a manner that the driving force is differentially transmittable to the wheels and the transmission of the driving force is interruptible. The apparatus includes: a differential case; a differential gear mechanism including a pair of side gears and a plurality of pinion gears; an intermediate shaft coupled to one of the side gears such that the intermediate shaft is not rotatable relative to this side gear; and a clutch mechanism to transmit a driving force from the intermediate shaft to one of the wheels in a manner that the transmission of the driving force is interruptible. The clutch mechanism includes: coaxial relatively rotatable first and second rotational members; and a plurality of clutch plates disposed between the rotational members. The first rotational member is spline-fitted to the intermediate shaft.

Abstract: A driving force transmission apparatus includes: a pinion gear shaft having a pinion teeth portion, a first shaft portion extending from one side of the pinion teeth portion, and a second shaft portion extending from the other side of the pinion teeth portion; a ring gear meshing with the pinion teeth portion; a clutch housing capable of rotating relative to the pinion gear shaft on a rotation axis in coincidence with a rotation axis of the pinion gear shaft; a clutch mechanism located between the clutch housing and the first shaft portion of the pinion gear shaft; and a differential carrier accommodating the ring gear. The first shaft portion and the second shaft portion of the pinion gear shaft are supported by a first bearing and a second bearing, respectively. The clutch housing is supported by the pinion gear shaft through a third bearing fitted on the first shaft portion.

Abstract: A drive force transfer device that includes a friction clutch with improved response at the time when the friction clutch is pressed by a hydraulic pressure is provided. A drive force transfer device has: a clutch drum; an inner shaft; a friction clutch that has a plurality of outer clutch plates that are rotatable together with the clutch drum and a plurality of inner clutch plates that are rotatable together with the inner shaft; a piston that receives a hydraulic pressure supplied to a cylinder to press the friction clutch; and a hydraulic circuit that supplies the cylinder with working oil. The hydraulic circuit has a first pump portion that supplies the cylinder with the working oil, and a second pump portion that supplies the cylinder with the working oil at a pressure that is higher than that of the working oil supplied by the first pump portion.

Abstract: An electromagnetic clutch device includes meshing member connected to a first rotational member, a biasing member that biases the meshing member in a direction where a second meshing portion is meshed with a first meshing portion, and a pressing mechanism including a locking portion that presses the meshing member against a biasing force of the biasing member so as to axially move the meshing member. The locking portion is axially immovable relative to the second rotational member, and a cylindrical cam member is provided with a plurality of locked portions to be locked at different axial positions. Locking of the locking portion is shifted from one of the plurality of locked portions to another locked portion placed at a different axial position, and friction torque is caused to synchronize rotation of the first rotational member with that of the second rotational member.

Abstract: A driving-force distribution device is provided that can supply lubricant to an above-positioned pinion gear among a pair of pinion gears even when rotation of a differential case of a differential mechanism stops in a two-wheel-drive mode of a four-wheel-drive vehicle. A driving-force distribution device mounted on a four-wheel-drive vehicle includes a differential mechanism and a clutch mechanism. The differential mechanism includes a differential case, a pinion shaft, a pair of pinion gears, and a pair of side gears. In the pinion shaft, a flow passage is formed through which a lubricant is allowed to flow from the below-positioned pinion gear among the pair of pinion gears toward the above-positioned pinion gear in the two-wheel-drive mode in which the pair of pinion gears rotate in opposite directions with the differential case not rotating. The lubricant is supplied to the flow passage by rotation of the below-positioned pinion gear.

Abstract: A driving force transmission device includes: a switch member that switches a first rotary member and a second rotary member between a coupled state and a decoupled state; a second friction member that generates a frictional force between the rotary members; a piston member that has first to sixth engaged portions formed in the shape of a staircase and that presses the switch member and the second friction member in an axial direction; a biasing mechanism that presses the switch member and the second friction member toward the piston member; and an engaging member that engages with one of the plurality of engaged portions. The engaging member rotates the piston member by sliding on a plurality of tilted surfaces of the plurality of engaged portions, and the piston member is always pressed toward the engaging member by a biasing force of the biasing mechanism.

Abstract: An electromagnetic clutch device includes meshing member connected to a first rotational member, a biasing member that biases the meshing member in a direction where a second meshing portion is meshed with a first meshing portion, and a pressing mechanism including a locking portion that presses the meshing member against a biasing force of the biasing member so as to axially move the meshing member. The locking portion is axially immovable relative to the second rotational member, and a cylindrical cam member is provided with a plurality of locked portions to be locked at different axial positions. Locking of the locking portion is shifted from one of the plurality of locked portions to another locked portion placed at a different axial position, and friction torque is caused to synchronize rotation of the first rotational member with that of the second rotational member.

Abstract: An electromagnetic clutch device includes: a meshing member; an electromagnetic coil; an armature; a cylindrical cam member; and a locking portion. The cam member is provided with a plurality of locked portions to be locked by the locking portion at different axial positions, such that the plurality of locked portions is formed adjacent to each other in a circumferential direction; the cam member rotates only by a first predetermined angle due to an axial movement of the armature from a first position to a second position, and the cam member further rotates only by a second predetermined angle due to a movement of the armature from the second position to the first position; and when locking of the locking portion is shifted from one of the plurality of locked portions to another locked portion circumferentially adjacent thereto so that the locking portion locks the another locked portion at a different axial position, the second meshing portion is meshed with the first meshing portion.

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 driving force transmission device includes: a switch member that switches a first rotary member and a second rotary member between a coupled state and a decoupled state; a second friction member that generates a frictional force between the rotary members; a piston member that has first to sixth engaged portions formed in the shape of a staircase and that presses the switch member and the second friction member in an axial direction; a biasing mechanism that presses the switch member and the second friction member toward the piston member; and an engaging member that engages with one of the plurality of engaged portions. The engaging member rotates the piston member by sliding on a plurality of tilted surfaces of the plurality of engaged portions, and the piston member is always pressed toward the engaging member by a biasing force of the biasing mechanism.