Patent ID: 9599169
Date: 2017-03-21
CPC Classifications: F16D

Claim:
1. A lubricating structure for a friction engagement element of an automatic transmission, the lubricating structure comprising: a first friction engagement element provided radially outside of a tubular wall extending in an axial direction in a transmission case of the automatic transmission, and configured to be engaged and released by a first piston configured to move forward and backward in the axial direction; and a second piston provided radially inside of the tubular wall, configured to move forward and backward in the axial direction, and configured to engage and release a second friction engagement element, wherein the tubular wall includes a communication hole communicating a radially inside of the tubular wall with a radially outside of the tubular wall, a feed port is provided for lubricating oil and located radially inside of the second piston, and the second piston includes a communication passage radially passing through the second piston and communicating the feed port with the communication hole such that lubricating oil is supplied from the communication hole to the radially outside of the tubular wall when the second piston is in an initial position in which the second friction engagement element is in a released state.