Patent attributes
An automatic transmission includes a first brake including first clutch plates; a pump cover defining a first receiving chamber, and a second receiving chamber receiving a planetary gear; a first cylindrical portion including splines; a second cylindrical portion located radially inside the first cylindrical portion; a first cylinder chamber formed radially inside the first cylindrical portion; and a first piston including a first radially extending portion, and a second radially extending portion, the first piston being arranged to push the first clutch plates, by using the second radially extending portion, radially inside the first cylindrical portion. The automatic transmission further includes a lubricating oil supply hole located at a radial position which is between the first cylinder chamber and the first cylindrical portion, and which is separated from the first cylinder chamber in the radial direction; and a connection groove connecting the lubricating oil supply hole and the splines.
