An automatic transmission may include a rotating shaft; a slider portion provided on the rotating shaft; a first connecting member having one end hinged to the rotating shaft and the other end rising or falling by a centrifugal force as the rotating shaft rotates; a second connecting member having one end hinged to the first connecting member and the other end connected to a slider portion to vertically slide the slider as the first connecting member rises or falls; a diaphragm spring coupled to the slider portion and deformed in an axial direction of the rotating shaft depending on position of the slider portion; a shift fork connected to the slider portion or the diaphragm spring and engaging a synchronizer with a shift stage gear depending on position of the slider portion; an elastic regulator controlling an elastic force of the diaphragm spring; and a controller controlling the elastic regulator.

An automatic transmission may include rotation shaft, sliding unit mounted on the rotation shaft and slidable up and down along the rotation shaft, diaphragm spring coupled to the sliding unit and deformed to be oriented toward first or second end of the rotation shaft along the rotation shaft according to position of the sliding unit, shift fork connected to the sliding unit or the diaphragm spring and configured to cause synchronizer to engage with speed change gear according to the position of the sliding unit, sliding-unit position adjuster connected to the sliding unit and adjusting the position of the sliding unit by causing the sliding unit to slide up or down along the rotation shaft, and controller for controlling the sliding-unit position adjuster to adjust elastic force of the diaphragm spring according to the vehicle speed by causing the sliding unit to slide upward or downward along the rotation shaft.

An automatic transmission may include rotation shaft, sliding unit mounted on the rotation shaft and slidable up and down along the rotation shaft, diaphragm spring coupled to the sliding unit and deformed to be oriented toward first or second end of the rotation shaft along the rotation shaft according to position of the sliding unit, shift fork connected to the sliding unit or the diaphragm spring and configured to cause synchronizer to engage with speed change gear according to the position of the sliding unit, sliding-unit position adjuster connected to the sliding unit and adjusting the position of the sliding unit by causing the sliding unit to slide up or down along the rotation shaft, and controller for controlling the sliding-unit position adjuster to adjust elastic force of the diaphragm spring according to the vehicle speed by causing the sliding unit to slide upward or downward along the rotation shaft.

An automatic transmission may include a rotating shaft; a slider portion provided on the rotating shaft; a first connecting member having one end hinged to the rotating shaft and the other end rising or falling by a centrifugal force as the rotating shaft rotates; a second connecting member having one end hinged to the first connecting member and the other end connected to a slider portion to vertically slide the slider as the first connecting member rises or falls; a diaphragm spring coupled to the slider portion and deformed in an axial direction of the rotating shaft depending on position of the slider portion; a shift fork connected to the slider portion or the diaphragm spring and engaging a synchronizer with a shift stage gear depending on position of the slider portion; an elastic regulator controlling an elastic force of the diaphragm spring; and a controller controlling the elastic regulator.