Mazda Motor Corporation

Yoshihiko Fujita

Tatsuhiko Iwasaki

Tatsutoshi Mizobe

Tokimori Saka

Takamichi Teraoka

Naohiro Sakaue

Keiichi Nakamura

Shinya Kamada

Kazuhiko Ueda

Junichi Doi

Norio Iwashita

Seiji Esaki

Satoshi Komori

Tetsuo Yamada

Esaki Seiji

The automatic transmission has, on an axis of a power transmission shaft: a one-side clutch including a plurality of friction plates; and an other-side clutch including a plurality of friction plate. A pressing section of a piston of the one-side clutch and a pressing section of a piston of the other-side clutch are arranged to overlap each other in an axial direction. On one side in the axial direction of the plurality of friction plates of the one-side clutch, a radial section of the piston of the one-side clutch and a radial section of the piston of the other-side clutch are arranged in parallel in the axial direction. Pressure-receiving sections of the pistons of the one-side clutch and the other-side clutch and bearing sections of the pistons of the one-side clutch and the other-side clutch are aggregated and arranged on a radially inner side.

Automatic transmission

An automatic transmission has a one-side clutch and an other-side clutch in an axial direction, the one-side clutch and the other-side clutch being aligned in the axial direction on an axis of a power transmission shaft. These clutches respectively include: drum sections; hub sections; friction plates that are engaged in an axially slidable manner between the drum sections and the hub sections; and pistons that press the friction plates. The friction plates in the one-side and other-side clutches are arranged in parallel in the axial direction. The pistons in the one-side clutch and the other-side clutch are arranged on one sides in the axial direction of the friction plates and are arranged such that axial positions thereof overlap. The piston in the other-side clutch penetrates the friction plate in the one-side clutch in the axial direction.

An automatic transmission includes a clutch device having a clutch hub, a clutch drum, a friction plate, a piston, and a hydraulic chamber. The clutch drum includes an outer-side cylindrical portion, a disc-shaped first radial portion extending radially inwardly, an axial portion extending axially from the first radial portion, and a disc-shaped second radial portion extending radially inwardly from the axial portion. The piston includes a pressing portion disposed between the first radial portion and the friction plate side, and a disc-shaped piston radial portion extending radially inwardly from the pressing portion. The hydraulic chamber is provided radially inwardly from the axial portion and on the non-friction-plate side of the piston radial portion. A comb-teeth portion is provided at a radially intermediate portion of the piston radial portion. The axial portion and the piston radial portion intersect with each other in a comb-teeth shape.

There is provided an automatic transmission comprising a first shaft capable of receiving torque from an engine, and four planetary gear sets arranged coaxially on the first shaft and in series in an axial direction of the first shaft. Each of the four planetary gear sets has a single sun gear and a single ring gear. Further, the automatic transmission comprises an output wheel arranged coaxially on the first shaft, and capable of outputting torque transmitted from the engine through some of the four planetary gear sets. The output wheel is arranged between two of the four planetary gear sets. Accordingly, the noise or vibration from the planetary gear sets in the automatic transmission may be reduced, while the overall length of the first shaft may be made shorter, and the overall size of the automatic transmission may be made smaller.

Automatic transmission for automotive vehicles

An automatic transmission is provided comprising a transmission case, a first shaft housed in and rotationally supported by said transmission case, and capable of receiving torque from an engine, a first shifting gear mechanism arranged coaxially with the first shaft, and a second shifting gear mechanism including a second planetary gear set. The second planetary gear set is housed within the transmission case and arranged coaxially with the first shaft, one of its sun and ring gears is capable of rotating together with the input shaft, and the other of the sun and ring gears is fixed to the transmission case. The automatic transmission further comprises first and second frictional elements arranged at least partly overlapped with the second planetary gear set in the axial direction between the planetary gear set and the transmission case in the radial direction. Accordingly, the plurality of frictional elements may be arranged on a shorter shaft without excessively increasing the radial size of the automatic transmission.

In an automatic transmission (AT) in which an input shaft (Input) and an output gear (Output) are disposed on the same axis and three clutches (C-C) and two brakes (B, B) are selectively operated to provide six forward speeds, first and second planetary gear sets (GS, GS) are configured to consistently reduce the speed of input rotation and output the speed-reduced rotation, thereby enabling downsizing of them. The first and second planetary gear sets (GS, GS) are arranged in a transmission case at both the axial ends thereof. Third and fourth planetary gear sets (GS, GS) are connected to each other to have four rotation elements in combination, thereby constituting a Simpson planetary gear train. One of the four rotation elements (a fourth carrier (PC) in an illustrated example) is connected to the output gear (Output). Rotations input and reduced in speed by the first and second planetary gear sets (GS, GS) are input to sun gears (S, S) of the third and fourth planetary gear sets (GS, GS), respectively. First to third clutches (C-C) and a first brake (B) are arranged to surround the first and second planetary gear sets (GS, GS).

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Aki-gun, Japan

Yoshihiko Fujita