| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic transmission that prevents air from being mixed into a second hydraulic chamber even when among a plurality of hydraulic chambers provided in the piston of a friction fastening element and hydraulic pressure is supplied only to a first hydraulic chamber and is not supplied to the second hydraulic chamber.SOLUTION: Among an A chamber 61 and a B chamber 62 that are provided in the piston of an L-R brake 60, hydraulic control is executed such that hydraulic pressure is supplied only to the B chamber 62 and is not supplied to the A chamber 61. At execution of the hydraulic control, the volume of an oil passage to the A chamber 61 from a drain port 128a of oil passages 63, 125, 126, 128 communicating with the A chamber 61 is set to be a larger value than an increase amount of the volume of the A chamber 61 increasing with the stroke of the piston at the execution of the hydraulic control. |
