Patent ID: 9523395
Filing Date: 2016-12-20
CPC Classification: F16D

Claim Text:
1. A driving force transmission device, comprising: a first rotary member and a second rotary member which can rotate relative to each other; a switch member that can switch the first rotary member and the second rotary member between a coupled state and a decoupled state by moving in an axial direction; a friction member that generates a frictional force suppressing differential rotation between the first and second rotary members, by moving in the axial direction; a cylindrical piston member that has a plurality of engaged portions formed in a shape of a staircase in a circumferential direction, and that can press the switch member and the friction member toward one side in the axial direction; a pressing member that is disposed so as to face the engaged portions of the piston member in the axial direction, and that advances and withdraws between a first position where the pressing member presses the piston member in the axial direction and a second position where the pressing member does not press the piston member; a biasing mechanism that presses the switch member and the friction member toward the piston member; and an engaging member that engages with one of the plurality of engaged portions; wherein the engaged portions of the piston member have a tilted surface tilted with respect to the circumferential direction of the piston member, by moving to the first position, the pressing member presses the tilted surface of the engaged portion and rotates the piston member by a predetermined amount to cause a tilted surface of another one of the engaged portions which adjoins the engaged portion to face the engaging member, when the pressing member returns to the second position, the tilted surface of the another engaged portion slides on the engaging member due to a biasing force of the biasing mechanism, and the piston member thus further rotates, whereby the engaging member engages with the another engaged portion, and the piston member is always pressed toward the engaging member by the biasing force of the biasing mechanism.