Patent ID: 8376898

Claim:
An automatic transmission comprising: a first planetary gearset including a first sun gear, a first ring gear, and a first carrier supporting a first double pinion meshed with the first sun gear and the first ring gear; a second planetary gearset including a second sun gear, a second carrier supporting a second pinion meshed with the second sun gear, and a second ring gear meshed with the second pinion; a third planetary gearset including a third sun gear, a third carrier supporting a third pinion meshed with the third sun gear, and a third ring gear meshed with the third pinion, the first sun gear and the second sun gear being directly linked together to constitute a first rotary member and the second ring gear and the third sun gear being directly linked together to constitute a second rotary member; an input shaft linked directly to the first ring gear; an output shaft linked directly to the third carrier; a first frictional element selectively linked between the first carrier and the second carrier; a second frictional element selectively linked between the first ring gear and the second carrier; a third frictional element selectively linked between the first rotary member and the third carrier; a fourth frictional element selectively linked between the first rotary member and the third ring gear; a fifth frictional element capable of stopping in an engaged state a revolution of the first carrier; and a sixth frictional element capable of stopping in the engaged state the revolution of the third ring gear, the six frictional elements being appropriately released or engaged to make a gear shift to a gear shift stage of at least eight forward speeds in order for a torque from the input shaft to be enabled to be output to the output shaft and, from among the six frictional elements, a combination of simultaneous engagements of three frictional elements achieving the at least eight forward speeds and one reverse speed.