A transmission assembly includes a common ring gear assembly, a first sun gear, a first planet carrier, a second sun gear and a second planet carrier. A set of planet gears of each one of the first and second planet carriers meshing with the common ring gear assembly. The set of planet gears of the first planet carrier meshing with the first sun gear and the set of planet gears of the second planet carrier meshing with the second sun gear. The transmission assembly further includes a transmission housing.

The second sun gear is adapted to be connected to a transmission input shaft;

the common ring gear assembly is adapted to be connected to a transmission output shaft, and

the second planet carrier and the first sun gear are operatively connected to each other.

A control device for an automatic transmission is provided, which includes a vehicle-propelling friction engagement element configured to be engaged when a vehicle starts traveling, an other friction engagement element, a vehicle-propelling friction engagement element temperature detector configured to detect a temperature of the vehicle-propelling friction engagement element, an other friction engagement element temperature detector configured to detect a temperature of the other friction engagement element, and a processor configured to execute lubricant supply control logic to control supply of lubricant to the vehicle-propelling friction engagement element and the other friction engagement element. The lubricant supply control logic switches the supply amount of lubricant to the vehicle-propelling friction engagement element according to the temperature of the vehicle-propelling friction engagement element, and switches the supply amount of lubricant to the other friction engagement element according to the temperature of the other friction engagement element.

A transmission arrangement includes a transmission housing including a transmission housing wall assembly defining a transmission housing cavity enclosing at least a first and a second planetary gear set, wherein at least an external portion of each one of a first and second locking mechanisms of the planetary gear sets is located on one side of the transmission housing wall assembly and the transmission housing cavity is located on an opposite side of the transmission housing wall assembly.

An automatic transmission is provided, which includes a brake including a fixed-side cylindrical member spline-coupled to a transmission case, a rotation-side cylindrical member coupled to a given rotating member, a plurality of friction plates disposed between the fixed-side cylindrical member and the rotation-side cylindrical member, and including a fixed-side friction plate configured to be spline-engaged with the fixed-side cylindrical member and a rotation-side friction plate configured to be spline-engaged with the rotation-side cylindrical member, and a piston configured to engage the plurality of friction plates. The automatic transmission includes a shock absorbing member disposed between a spline part of the transmission case and a spline part of the fixed-side cylindrical member and configured to absorb impact when the fixed-side cylindrical member rotates relative to the transmission case.

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.

A transmission arrangement includes a transmission housing including a transmission housing wall assembly defining a transmission housing cavity enclosing at least a first and a second planetary gear set, wherein at least an external portion of each one of a first and second locking mechanisms of the planetary gear sets is located on one side of the transmission housing wall assembly and the transmission housing cavity is located on an opposite side of the transmission housing wall assembly.

An automatic transmission includes a brake including a fixed-side cylindrical member spline-coupled to a transmission case, a rotation-side cylindrical member coupled to a given rotating member, a plurality of friction plates disposed between the fixed-side cylindrical member and the rotation-side cylindrical member, and including a fixed-side friction plate configured to be spline-engaged with the fixed-side cylindrical member and a rotation-side friction plate configured to be spline-engaged with the rotation-side cylindrical member, and a piston configured to engage the plurality of friction plates. The automatic transmission further includes a shock absorbing member disposed between a spline part of the transmission case and a spline part of the fixed-side cylindrical member and configured to absorb impact when the fixed-side cylindrical member rotates relative to the transmission case.

A transmission assembly includes a common ring gear assembly, a first sun gear, a first planet carrier, a second sun gear and a second planet carrier. A set of planet gears of each one of the first and second planet carriers meshing with the common ring gear assembly. The set of planet gears of the first planet carrier meshing with the first sun gear and the set of planet gears of the second planet carrier meshing with the second sun gear. The transmission assembly further includes a transmission housing. The second sun gear is adapted to be connected to a transmission input shaft; the common ring gear assembly is adapted to be connected to a transmission output shaft, and the second planet carrier and the first sun gear are operatively connected to each other.

A rotary drive system includes an electric motor, a speed reducer, and a lubricating oil-circulating unit. The electric motor has an electric motor casing forming a first accommodating space and a communication hole communicating downward. The speed reducer has a speed reducer casing forming a second accommodating space communicating with the first accommodating space through the communication hole. The lubricating oil-circulating unit has a lubricating oil flow path and a lubricating oil pump. The lubricating oil flow path connects the first accommodating space and the second accommodating space at the outside. The lubricating oil pump pumps lubricating oil from the second accommodating space side to the first accommodating space side.

A control device for an automatic transmission is provided, which includes a vehicle-propelling friction engagement element configured to be engaged when a vehicle starts traveling, an other friction engagement element, a vehicle-propelling friction engagement element temperature detector configured to detect a temperature of the vehicle-propelling friction engagement element, an other friction engagement element temperature detector configured to detect a temperature of the other friction engagement element, and a processor configured to execute lubricant supply control logic to control supply of lubricant to the vehicle-propelling friction engagement element and the other friction engagement element. The lubricant supply control logic switches the supply amount of lubricant to the vehicle-propelling friction engagement element according to the temperature of the vehicle-propelling friction engagement element, and switches the supply amount of lubricant to the other friction engagement element according to the temperature of the other friction engagement element.