Patent attributes
A parking lock device for an automatic transmission includes: a parking gear externally fixed to the output shaft; a parking lock pole displaced between a lock position, where the parking lock pole latches onto the parking gear to disable rotation of the parking gear, and an unlock position, where the parking lock disengages from the parking gear to enable rotation of the parking gear; a parking rod for displacing the parking lock pole toward and away from the parking gear; a drive lever that moves the parking rod; and a booster mechanism interposed between the parking rod and the drive lever that increases the driving force of the drive lever. Thus, the parking lock device makes the driving force applied by the drive lever when unlocking as small as possible and prevents inadvertent unlocking when in a locked state, thereby achieving smooth operation and enhanced reliability.