Aspects of the present invention relate to a rotor end member (20-1, 20-2) for conveying air through a rotor (6) of an electric machine (1). The rotor end member (20-1, 20-2) has at least one air inlet aperture (23-n) for conveyance of air into one or more first rotor aperture (12-n) formed in a radially inner section (RE1) of the rotor (6). The rotor end member (20-1, 20-2) also has at least one air outlet aperture (30-n) for discharging air from one or more second rotor aperture (13A-C) formed in a radially outer section (RE2) of the rotor (6). The present invention also relates to a rotor assembly (3); an electric machine (1); and a vehicle (V).

A power tool is provided including a gear case having a spindle, a motor case connected to a rear end of the gear case along a longitudinal axis; a handle portion extending from a rear end of the motor case along the longitudinal axis; a motor housed inside the motor case; a fan in rotational connection with the motor; at least one air intake arranged at least one of the motor case or the handle portion near the rear end of the motor case; and a power module including power switches for driving the motor and a heat sink. The power module is housed in at least one of the motor case or the handle portion near the rear end of the motor case such that rotation of the fan causes air flow to enter through the air intake and flow near the heat sink and through the motor.

A power tool is provided including a gear case having a spindle, a motor case connected to a rear end of the gear case along a longitudinal axis; a handle portion extending from a rear end of the motor case along the longitudinal axis; a motor housed inside the motor case; a fan in rotational connection with the motor; at least one air intake arranged at least one of the motor case or the handle portion near the rear end of the motor case; and a power module including power switches for driving the motor and a heat sink. The power module is housed in at least one of the motor case or the handle portion near the rear end of the motor case such that rotation of the fan causes air flow to enter through the air intake and flow near the heat sink and through the motor.

A series fan frame body structure includes a first fan frame body, a second fan frame body and a serial connection frame body. The serial connection frame body has a first opening and a second opening. The first and second openings arranged in nonparallel to each other. The first and second fan frame bodies are respectively disposed at the first and second openings. The first and second fan frame bodies are inclined from each other. The first and second fan frame bodies are serially connected in a nonparallel form. Therefore, in the system, due to the resistance of the structure with such configuration, the audio frequency dipole structure is destructed so that the periodical noise and vibration characteristic are lowered.

A series fan frame body structure includes a first fan frame body, a second fan frame body and a serial connection frame body. The serial connection frame body has a first opening and a second opening. The first and second openings arranged in nonparallel to each other. The first and second fan frame bodies are respectively disposed at the first and second openings. The first and second fan frame bodies are inclined from each other. The first and second fan frame bodies are serially connected in a nonparallel form. Therefore, in the system, due to the resistance of the structure with such configuration, the audio frequency dipole structure is destructed so that the periodical noise and vibration characteristic are lowered.

Air circulation passages connect an accommodation space of an electronic control unit to the outside to circulate air to buffer internal pressure fluctuations. The accommodation space side of the air circulation passages is formed as a divided air circulation passage with a plurality of passages, a cooling object member is arranged to come in thermal contact with air flowing through the divided air circulation passage, and the total cross-sectional area of the divided air circulation passage is smaller than the cross-sectional area of the air circulation passages that are not divided. Because the accommodation space of the electronic control unit is connected to the outside, internal pressure fluctuations can be buffered, and increasing the flow velocity of the air flowing through the divided air circulation passage on the accommodation space side of the air circulation passages allows heat inside the accommodation space to be efficiently radiated to the outside.

A rotor for an electric machine, especially a generator of a direct drive wind turbine, includes a cylindrical rotor housing with several magnet means arranged at the inner housing surface, wherein each magnet means includes several magnet elements arranged in a row parallel to an axis of rotation, wherein the inner housing surface is provided with at least one groove-like recesses extending parallel to the axis of rotation, wherein each recess is covered by the magnet elements of a row, and wherein at least two magnet elements in at least some of the rows are arranged with at least one gap extending in the circumferential direction, which gap communicates with the respective recess.

A drive system for a rail vehicle includes at least one drive motor and at least one cooling apparatus for cooling the at least one drive motor and/or other components of the drive system, in particular a current converter. The drive system is constructed and intended to use kinetic energy of the rail vehicle for operation of the cooling apparatus. A rail vehicle having the drive system and methods for the forward movement of a rail vehicle are also provided.

A drive system for a rail vehicle includes at least one drive motor and at least one cooling apparatus for cooling the at least one drive motor and/or other components of the drive system, in particular a current converter. The drive system is constructed and intended to use kinetic energy of the rail vehicle for operation of the cooling apparatus. A rail vehicle having the drive system and methods for the forward movement of a rail vehicle are also provided.

A breather device includes an intake path configured to communicate between an interior space of a target case and an exterior space, an exhaust path configured to communicate between the interior space and the exterior space and at least partially separated from the intake path, an intake valve inserted in the intake path and configured to allow outside air to flow into the interior space only when an internal pressure Pi is lower, at least by a fixed extent, than an external pressure Po, and an exhaust valve inserted in the exhaust path and configured to allow gas within the interior space to flow toward the exterior space only when the internal pressure Pi is higher, at least by a fixed extent, than the external pressure Po, and a water stop filter disposed downstream of the intake valve in an intake air flowing direction in the intake path.