A cooling system for a drive device with several electric machines, the cooling system including a hydraulic circuit for a coolant including a cooling part in a gearbox of the drive device for cooling the gearbox, and an air/coolant heat exchanger including cooling walls forming channels for circulating coolant for the cooling thereof, an air cooling circuit including a plurality of fans, rotationally coupled to the gearbox, a cooling part between the cooling walls of the air/liquid heat exchanger, wherein the air sucked in and propelled by the fans circulates by sweeping over the cooling walls in order to cool them.

A cooling system for a drive device with several electric machines, the cooling system including a hydraulic circuit for a coolant including a cooling part in a gearbox of the drive device for cooling the gearbox, and an air/coolant heat exchanger including cooling walls forming channels for circulating coolant for the cooling thereof, an air cooling circuit including a plurality of fans, rotationally coupled to the gearbox, a cooling part between the cooling walls of the air/liquid heat exchanger, wherein the air sucked in and propelled by the fans circulates by sweeping over the cooling walls in order to cool them.

A motor assembly can include a motor shaft, a stator assembly, and a rotor assembly, and can include a cooling jacket. The cooling jacket can include an inner wall facing radially inwardly towards the stator assembly and an opposite outer wall facing radially outwardly, a circumferential internal fluid passageway for allowing a cooling fluid to be pumped through an interior of the cooling jacket, the internal fluid passageway being disposed between the inner and outer walls and extending between an inlet and an outlet, a mounting pad receiving, at an opening in the outer wall, a heat generating component associated with the motor assembly, the opening being in fluid communication with the internal fluid passageway such that the cooling fluid can provide cooling to the heat generating component.

A motor assembly can include a motor shaft, a stator assembly, and a rotor assembly, and can include a cooling jacket. The cooling jacket can include an inner wall facing radially inwardly towards the stator assembly and an opposite outer wall facing radially outwardly, a circumferential internal fluid passageway for allowing a cooling fluid to be pumped through an interior of the cooling jacket, the internal fluid passageway being disposed between the inner and outer walls and extending between an inlet and an outlet, a mounting pad receiving, at an opening in the outer wall, a heat generating component associated with the motor assembly, the opening being in fluid communication with the internal fluid passageway such that the cooling fluid can provide cooling to the heat generating component.

A motor, a reduction gear, a differential gear, and a housing having a cylindrical shape are included. The motor has a rotor and a stator. The rotor rotates around a motor axis. The stator faces the rotor in a radial direction with a gap interposed between them. The reduction gear includes a planetary gear mechanism, and can increase rotational power output from the motor according to a reduction ratio. The differential gear distributes and outputs the rotational power from the reduction gear. The housing houses the motor, the reduction gear, and the differential gear arranged in an axial direction with the motor axis as a common rotation axis. The housing includes a first attachment portion and a second attachment portion arranged on an outer peripheral surface. The first attachment portion and the second attachment portion are arranged on the opposite sides in a direction perpendicular to the axial direction with respect to the motor axis.

A motor, a reduction gear, a differential gear, and a housing having a cylindrical shape are included. The motor has a rotor and a stator. The rotor rotates around a motor axis. The stator faces the rotor in a radial direction with a gap interposed between them. The reduction gear includes a planetary gear mechanism, and can increase rotational power output from the motor according to a reduction ratio. The differential gear distributes and outputs the rotational power from the reduction gear. The housing houses the motor, the reduction gear, and the differential gear arranged in an axial direction with the motor axis as a common rotation axis. The housing includes a first attachment portion and a second attachment portion arranged on an outer peripheral surface. The first attachment portion and the second attachment portion are arranged on the opposite sides in a direction perpendicular to the axial direction with respect to the motor axis.

An electric hydrofoil board having a submersion-cooled powertrain is provided. A powertrain assembly, which includes a motor housed in a motor assembly and an electronic speed controller housed in a nose cone assembly that is fastened to the motor assembly, is attached to a lower end of a mast of the hydrofoil board so that the powertrain assembly remains submerged at all times during normal use of the hydrofoil board in a body of water. The flow of water around the powertrain assembly during normal use cools heat-generating components of the electronic speed controller and motor.

An electric hydrofoil board having a submersion-cooled powertrain is provided. A powertrain assembly, which includes a motor housed in a motor assembly and an electronic speed controller housed in a nose cone assembly that is fastened to the motor assembly, is attached to a lower end of a mast of the hydrofoil board so that the powertrain assembly remains submerged at all times during normal use of the hydrofoil board in a body of water. The flow of water around the powertrain assembly during normal use cools heat-generating components of the electronic speed controller and motor.

A fan motor according to an embodiment includes a bearing holder, a stator, a circuit board, and a synthetic resin. The stator is mounted at an outer circumference of the bearing holder. The circuit board is electrically connected to a coil of the stator, is mounted at a surface of the base part at an opposite side to the bearing holder, and extends from a base part to a connector housing. The synthetic resin seals the bearing holder, the stator, and the circuit board, except for both end faces of the bearing holder. The connector housing has a gate opening that is injected with the synthetic resin at the time of sealing and ribs that are at an opposite side to the gate opening with the circuit board between the ribs, and tops of the ribs making contact with the circuit board.

A motor includes a housing including a housing base and a housing shaft portion that is provided on the housing base and extends in a direction along a rotation center axis, a motor stator that is disposed outward in a radial direction of the housing shaft portion, a motor rotor that is provided between the motor stator and the housing shaft portion, a bearing that is provided inward in a radial direction of the motor rotor and rotatably supports the motor rotor to the housing shaft portion, a sealing structure that is provided on an opposite side to the housing base in an axial direction of the motor rotor and seals between the motor rotor and the housing shaft portion, and a resolver that is configured to detect rotation of the motor rotor.