# US 2017/0284516 A1 · Automatic transmission > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0284516 A1 - Document ID: US20170284516A1 - Status: Published application - Kind: A1 - Application number: 15/506,132 - Filed: 2015-10-20 - Published: 2017-10-05 - Earliest claimed: 2014-10-23 - Assignees: Mazda Motor Corporation - Applicants: Mazda Motor Corporation - Inventors: Shinya KAMADA; Tatsuhiko IWASAKI - Web page: https://patentgrep.com/patent/US20170284516A1 ## CPC - F16H 3/666: {with intermeshing orbital gears (F16H3/663 takes precedence)} - F16H 3/663: {with conveying rotary motion between axially spaced orbital gears, e.g. a stepped orbital gear or Ravigneaux} - F16H 57/082: {Planet carriers} - F16H 57/10: Braking arrangements - F16H 2057/087: {Arrangement and support of friction devices in planetary gearings, e.g. support of clutch drums, stacked arrangements of friction devices} - F16H 2200/006: the gear ratios comprising eight forward speeds - F16H 2200/0065: the gear ratios comprising nine forward speeds - F16H 2200/201: with three sets of orbital gears - F16H 2200/2012: with four sets of orbital gears - F16H 2200/2023: using a Ravigneaux set with 4 connections - F16H 2200/2043: with five engaging means - F16H 2200/2046: with six engaging means - F16H 2200/2064: using at least one positive clutch, e.g. dog clutch - F16H 2200/2094: using positive clutches, e.g. dog clutches - F16H: GEARING ## Abstract An automatic transmission includes a first planetary gear set, a second planetary gear set, and a first brake. A first sun gear includes a first split sun gear on a drive source side, and a second split sun gear on a side opposite to the drive source. The first spilt sun gear is coupled to the first brake, and is fixed to a transmission case during engagement of the first brake. The second split sun gear is constantly coupled to a second sun gear. An input shaft is constantly coupled to a first carrier while passing through the first split sun gear, and between the first and second split sun gears. An output shaft is constantly coupled to a second carrier. ## Claims ### Claim 1 An automatic transmission, comprising: an input shaft coupled to a drive source; an output shaft disposed coaxially with the input shaft on a side of the input shaft opposite to the drive source; a first planetary gear set including a first sun gear, a first carrier, and a first ring gear; a second planetary gear set disposed on a side of the first planetary gear set opposite to the drive source, and including a second sun gear, a second carrier, and a second ring gear; a third planetary gear set including a third sun gear, a third carrier, and a third ring gear; a fourth planetary gear set including a fourth sun gear, a fourth carrier, and a fourth ring gear; a first clutch, a second clutch, and a third clutch; a first brake disposed on a drive source side of the first planetary gear set; a second brake; and a transmission case which accommodates the first planetary gear set, the second planetary gear set, the third planetary gear set, the fourth planetary gear set, the first clutch, the second clutch, the third clutch, the first brake, and the second brake, wherein the first sun gear includes a first split sun gear on a drive source side, and a second split sun gear on a side opposite to the drive source, the first split sun gear is coupled to the first brake, and is fixed to the transmission case during engagement of the first brake, the second split sun gear is constantly coupled to the second sun gear, the input shaft is constantly coupled to the first carrier while passing through the first split sun gear, and between the first and second split sun gears, the output shaft is constantly coupled to the second carrier, the first ring gear and the third sun gear are constantly coupled to each other, the second carrier and the third carrier are constantly coupled to each other, the second ring gear and the fourth carrier are constantly coupled to each other, the first clutch disconnectably connects the fourth sun gear to the input shaft and the first carrier, the second clutch disconnectably connects the fourth sun gear to the first ring gear and the third sun gear, the third clutch disconnectably connects the fourth sun gear to the third ring gear, and the second brake disconnectably connects the fourth ring gear to the transmission case. ### Claim 2 (canceled) ### Claim 3 (depends on 1) The automatic transmission according to claim 1, wherein a first gear position is attained when the first clutch, the first brake, and the second brake are engaged, a second gear position is attained when the second clutch, the first brake, and the second brake are engaged, a third gear position is attained when the first clutch, the second clutch, and the second brake are engaged, a fourth gear position is attained when the second clutch, the third clutch, and the second brake are engaged, a fifth gear position is attained when the first clutch, the third clutch, and the second brake are engaged, a sixth gear position is attained when the first clutch, the second clutch, and the third clutch are engaged, a seventh gear position is attained when the first clutch, the third clutch, and the first brake are engaged, an eighth gear position is attained when the second clutch, the third clutch, and the first brake are engaged, and a reverse gear position is attained when the third clutch, the first brake, and the second brake are engaged. ### Claim 4 (depends on 1) The automatic transmission according to claim 1, further comprising: a fourth clutch which disconnectably connects the second sun gear to the second carrier and the output shaft, or disconnectably connects the second ring gear to the second carrier and the output shaft. ### Claim 5 (depends on 4) The automatic transmission according to claim 4, wherein a first gear position is attained when the first clutch, the first brake, and the second brake are engaged, a second gear position is attained when the second clutch, the first brake, and the second brake are engaged, a third gear position is attained when the second clutch, the fourth clutch, and the second brake are engaged, a fourth gear position is attained when the first clutch, the second clutch, and the second brake are engaged, a fifth gear position is attained when the second clutch, the third clutch, and the second brake are engaged, a sixth gear position is attained when the first clutch, the third clutch, and the second brake are engaged, a seventh gear position is attained when the first clutch, the second clutch, and the third clutch are engaged, an eighth gear position is attained when the first clutch, the third clutch, and the first brake are engaged, a ninth gear position is attained when the second clutch, the third clutch, and the first brake are engaged, and a reverse gear position is attained when the third clutch, the first brake, and the second brake are engaged.