Mazda Motor Corporation

Mazda Motor Corporat Ion

Shota Yamakawa

Tomotaka Ishizaka

Tatsuhiko Iwasaki

Norio Iwashita

Provided is an automatic transmission with a compact arrangement that prevents rotation of a hub member, and efficiently supplies lubrication hydraulic oil to the friction plates. The automatic transmission comprises a brake in which a plurality of friction plates are arranged between the hub member and a drum member, wherein a biasing member, an engagement hydraulic pressure chamber, and a disengagement hydraulic pressure chamber are arranged radially inward of the friction plates at positions radially overlapping each other. The hub member comprises: a first hub member comprising a cylindrical portion having a splined region with which the friction plates are spline-engaged, wherein the first hub member s spline-engaged with a transmission casing; and a second hub member formed with a part of a lubrication oil supply passage, wherein the second hub member is fittingly engaged with the transmission casing such that it is connected to a valve body.

Automatic transmission

An automatic transmission with a brake is provided, the brake including a hub member coupled to a transmission case. The hub member includes a first hub member having a cylindrical part spline-engaged with friction plates and the transmission case, and forming a disengagement hydraulic chamber, a second hub member disposed at one side of the first hub member in the axial direction, fitted into the transmission case, and coupled to the one side of the first hub member in the axial direction by a first coupling member, and a third hub member disposed at the other side of the first hub member in the axial direction, coupled to the other side of the first hub member in the axial direction by a second coupling member, and forming an engagement hydraulic chamber. The first coupling member and the second coupling member are disposed radially inward of the disengagement hydraulic chamber.

An automatic transmission is provided, which includes a friction engaging element. The friction engaging element includes a plurality of friction plates disposed inside a transmission case, a piston configured to cause the plurality of friction plates to be engaged with each other, a spring configured to bias the piston, and a hydraulic chamber to which hydraulic fluid is supplied, the hydraulic fluid biasing the piston. The hydraulic chamber is disposed so as to overlap with the spring in a radially internal and external relationship.

An automatic transmission is provided, which includes a friction engaging element. The friction engaging element includes a plurality of friction plates disposed inside a transmission case, a piston configured to cause the plurality of friction plates to be engaged with each other, and a spring configured to bias the piston. The spring includes a first spring and a second spring with a longer free length than the first spring, and the first spring and the second spring are aligned in circumferential directions of the transmission case.

An automatic transmission is provided with a friction engaging element having a hub member, a drum member, friction plates disposed between the hub member and the drum member, and a piston configured to engage the friction plates. The hub member includes a first hub member made of ferrous material and having a cylindrical part provided with a spline part, the friction plates being spline-engaged with the spline part, and a second hub member made of aluminum-based material, disposed at a side part of the first hub member, and having a feed part for lubrication provided with a supply oil channel configured to supply hydraulic fluid for lubrication to the friction plates. A notch for lubrication is formed by circumferentially cutting the cylindrical part of the first hub member corresponding to the feed part of the second hub member. The feed part supplies the hydraulic fluid for lubrication through the notch.

An automatic transmission is provided, which includes a brake including a hub member which is coupled to a transmission case and includes first and second hub members, a drum member coupled to a given rotary member, friction plates, a piston configured to engage the friction plates, and a valve body disposed in a lower part of the transmission case. The first hub member includes a radially outer circumferential part formed with a first spline part spline-engaged with the transmission case, and a cylindrical part provided at a radially inner circumferential side and formed with a second spline part with which the friction plates are spline-engaged. The second hub member is disposed at a side part of the first hub member, is provided by fitting a radially outer circumferential part of the second hub member to the transmission case, and has a feed part for lubrication.

An automatic transmission is provided, which includes a brake and an oil channel forming member. The brake includes an inner stationary member coupled to a transmission case, an outer rotary member, a plurality of friction plates, a piston configured to cause the friction plates to be engaged, and a hydraulic chamber for engagement. The oil channel forming member forms a supply oil channel for engagement. The piston includes a pressing part, a hydraulic chamber forming part, and a coupling part. The oil channel forming member includes a bonding part, a hydraulic chamber forming part, and a coupling part. The bonding part and the coupling part of the oil channel forming member are disposed in a cutoff part formed in the coupling part of the piston, and are disposed to overlap with the coupling part of the piston in circumferential directions.

An automatic transmission is provided with a brake including a hub member coupled to a transmission case, a drum member coupled to a given rotary member, friction plates, a piston configured to engage the friction plates, and a hydraulic chamber for engagement disposed radially inward of the hub member and to which hydraulic fluid for biasing the piston in an engaging direction is supplied. The piston includes a pressing part configured to press the friction plates, a hydraulic chamber for engagement forming part, and a coupling part coupling the pressing part to the hydraulic chamber for engagement and extending radially. The hub member includes spline parts with which the friction plates are spline-engaged. Notches are formed by cutting the coupling part of the piston so as to be spaced apart from each other in circumferential directions, and end parts of the spline parts in axial directions enter into the notches.

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Hiroshima, Japan

Shota Yamakawa