Patent ID: 8286773
Filing Date: 2012-10-16
Classification: F16D

Abstract:
1. A frictional engagement apparatus comprising: an outer cylindrical member that is open at one axial end and in which splines are formed on an inner peripheral portion of the outer cylindrical member; an inner cylindrical member provided coaxially with the outer cylindrical member of which an outer peripheral portion is arranged within the outer cylindrical member, in the radial direction, and splines are formed on the outer peripheral portion of the inner cylindrical member facing the inner peripheral portion of the outer cylindrical member; a plurality of outer engagement members, each of which has an outer peripheral portion that spline-engages with the inner peripheral portion of the outer cylindrical member, wherein each outer engagement member of the plurality of engagement members is moveable in the axial direction with respect to the outer cylindrical member and rotates together with the outer cylindrical member; and a plurality of inner engagement members, each of which has an inner peripheral portion that spline-engages with the outer peripheral portion of the inner cylindrical member, wherein each inner engagement member of the plurality of engagement members is moveable in the axial direction with respect to the inner cylindrical member and rotates together with the inner cylindrical member, the inner engagement members being arranged coaxially and alternately with the outer engagement members, each inner engagement member being able to frictionally engage with the outer engagement members adjacent thereto, wherein an edge of each of the outer engagement members and/or each of the inner engagement members has a plurality of concave portions that dip inward in the plate thickness direction and a plurality of convex portions that protrude outward in the plate thickness direction, each convex portion being arranged between two adjacent concave portions; and ridge lines of the concave portions and the convex portions pass through positions away from a center point of each of the outer engagement members and/or each of the inner engagement members, a plurality of through holes are formed in the outer cylindrical member so as to correspond to the convex portions, the plurality of through holes penetrating the outer cylindrical member from an inner side of the outer cylindrical member to an outer side thereof, and the plurality of through holes are adjacent to outer ends of the corresponding concave portions and are each positioned on a forward side of the outer end of the corresponding concave portion with respect to a rotational direction of the outer cylindrical member.