Patent ID: 11859675
Assignee: MAZDA MOTOR CORPORATION
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F | IPC F

Claim 0:
1. A friction engagement device of an automatic transmission provided with a cylindrical drum part supporting an annular friction plate, the friction plate being provided in an outer circumferential side surface with a tooth part projecting radially outward, and the drum part comprising:
a cylindrical body including a spline part having serrations extending in an axial direction of the drum part and depressed radially outward so as to fit onto the tooth part of the friction plate, in an inner circumferential side surface;
a vertical wall part provided at an end side of the cylindrical body, and extending radially inward; and
a corner part provided between the cylindrical body and the vertical wall part,
wherein a drum recess is formed inside the corner part, the drum recess being connected to the serration of the spline part and being depressed toward an end side of the drum part in the axial direction,
wherein a cut part is provided outside the corner part, the cut part being connected to the drum recess and being cut in a circumferential direction of the drum part,
wherein the drum recess is opened to an outside by the cut part to form an oil gallery,
wherein the drum part is a die-cast article,
wherein inside the cylindrical body of the drum part, a cylindrical piston provided with an inclined part that inclines radially inward toward the end side of the cylindrical body is disposed between the vertical wall part and the friction plate, and
wherein a lubricating oil discharge hole passing through the inside and the outside of the inclined part is formed in the inclined part of the piston.