Abstract: A speed change device where the plurality of oil holes have a plurality of first oil holes that are closest to the piston in the axial direction and that are disposed side by side in a circumferential direction, and a plurality of different oil holes that are farther from the piston than the plurality of first oil holes in the axial direction, the plurality of oil holes enabling the working oil to be supplied to spaces between the plurality of inner friction plates and the outer friction plates; and a number of the plurality of different oil holes is smaller than a number of the plurality of first oil holes, the plurality of different oil holes being disposed side by side in the circumferential direction at a position that is farther from the piston than the plurality of first oil holes in the axial direction.

Abstract: A wet friction engagement element including a drum having a cylindrical drum portion; a hub having a cylindrical hub portion; an annular friction plate fitted in an inner periphery of the drum portion and having a friction material bonded to its surface; and an annular separator plate fitted on an outer periphery of the hub portion and capable of frictionally engaging with the friction plate.

Abstract: A speed change device where the plurality of oil holes have a plurality of first oil holes that are closest to the piston in the axial direction and that are disposed side by side in a circumferential direction, and a plurality of different oil holes that are farther from the piston than the plurality of first oil holes in the axial direction, the plurality of oil holes enabling the working oil to be supplied to spaces between the plurality of inner friction plates and the outer friction plates; and a number of the plurality of different oil holes is smaller than a number of the plurality of first oil holes, the plurality of different oil holes being disposed side by side in the circumferential direction at a position that is farther from the piston than the plurality of first oil holes in the axial direction.

Abstract: A planetary carrier where the second pinion gears are disposed so as to be at least partially located in the spaces between the adjacent bridge portions, an outer peripheral surface of each of the bridge portions is provided with a spline onto which a friction engagement plate constituting a friction engagement element is fitted, an inner peripheral surface of each of the bridge portions is provided with a pair of wall portions that extend in the axial direction along side edges on both sides of each of the bridge portions and protrude radially inward, and each of the bridge portions is provided with a plurality of oil holes through which an inside and an outside of each of the bridge portions communicate with each other.

Abstract: A planetary carrier where the second pinion gears are disposed so as to be at least partially located in the spaces between the adjacent bridge portions, an outer peripheral surface of each of the bridge portions is provided with a spline onto which a friction engagement plate constituting a friction engagement element is fitted, an inner peripheral surface of each of the bridge portions is provided with a pair of wall portions that extend in the axial direction along side edges on both sides of each of the bridge portions and protrude radially inward, and each of the bridge portions is provided with a plurality of oil holes through which an inside and an outside of each of the bridge portions communicate with each other.

Abstract: A wet friction engagement element including a drum having a cylindrical drum portion; a hub having a cylindrical hub portion; an annular friction plate fitted in an inner periphery of the drum portion and having a friction material bonded to its surface; and an annular separator plate fitted on an outer periphery of the hub portion and capable of frictionally engaging with the friction plate.