Patent ID: 7967716
Filing Date: 2011-06-28
Classification: F16H

Abstract:
1. An automatic transmission for a vehicle, comprising: a case having a side wall; an input shaft; a speed reduction planetary gear set that comprises a stationary element that is held stationary by the case, an input rotary element that receives the input rotation of the input shaft, and a speed reduction rotary element that outputs a reduced speed rotation at a speed less than that of the input rotation; a planetary gear unit that includes first, second, third, and fourth rotary elements that are arranged in rotational speed relationships according to their gear relationships; a first input transfer clutch, having input side and output side transfer members, for selective transfer of the input rotation to the first rotary element; a second input transfer clutch, having input side and output side transfer members, for selective transfer of the input rotation to the third rotary element; a first speed reduction transfer clutch, having input side and output side transfer members, for selective transfer of a reduced speed rotation through the speed reduction planetary gear set to the first rotary element; a second speed reduction transfer clutch, having input side and output side transfer members, for selective transfer of a reduced speed rotation through the speed reduction planetary gear set to the second rotary element; a first brake for selectively stopping rotation of the first rotary element by locking the first rotary element to the case; and a second brake for selectively stopping rotation of the third rotary element by locking the third rotary element to the case; and wherein the automatic transmission outputs output rotation at the fourth rotary element; wherein the first and second speed reduction transfer clutches are disposed on the speed reduction planetary gear set side relative to the planetary gear set; wherein the output side transfer members of the first and second speed reduction transfer clutches are respectively linked to the first rotary element and the second rotary element; wherein the first input transfer clutch is disposed on the speed reduction planetary gear set side relative to the planetary gear unit and its output side transfer member is linked to the first rotary element; wherein the second input transfer clutch is disposed on the speed reduction planetary gear set side relative to the planetary gear unit and its output side transfer member extends around the outer circumferences of the output side transfer members of the first and second speed reduction transfer clutches to link with the third rotary element; and wherein: a first forward speed is established by engaging the second speed reduction transfer clutch and locking the second brake; a second forward speed is established by engaging the second speed reduction transfer clutch and locking the first brake; a third forward speed is established by engaging the second speed reduction transfer clutch and the first speed reduction transfer clutch; a fourth forward speed is established by engaging the second speed reduction transfer clutch and the first input transfer clutch; a fifth forward speed is established by engaging the second speed reduction transfer clutch and the second input transfer clutch; a sixth forward speed is established by engaging the second input transfer clutch and the first input transfer clutch; a seventh forward speed is established by engaging the second input transfer clutch and the first speed reduction transfer clutch; an eighth forward speed is established by engaging the second input transfer clutch and locking the first brake; and a reverse speed is established by engaging the first speed reduction transfer clutch or the first input transfer clutch, and locking the second brake.