Abstract: A rotor core in which magnets are embedded is formed by stacking a plurality of steel sheets. Each steel sheet which has a disk shape has: six magnet insertion holes formed so as to allow permanent magnets to be inserted therein as a whole; circumferential-direction bridge portions connecting, in the circumferential direction, radially-outer-side steel sheets each formed at the peripheral part of the steel sheet, between the magnet insertion holes; and radial-direction bridge portions formed between the magnet insertion holes. The circumferential-direction bridge portions and the radial-direction bridge portions have coined portions having decreased sheet thicknesses and protruding in an arc shape in the sheet-thickness direction. The coined portions having decreased sheet thicknesses suppress short-circuit of a magnetic flux between magnetic poles, and formation of the arc shapes absorbs extension of these portions caused by a coining work, to suppress deformation of the steel sheet.

Abstract: A cooling system of an electric motor with a fan, including a fan configured to generate fluid flow for cooling the electric motor, and a duct forming a flow channel for guiding a fluid flow generated by the fan, includes at least one hole provided in the duct.

Abstract: A motor rotor includes a rotor core having a plurality of magnet insertion holes in each of which a permanent magnet is inserted, a flow path formed on a radially inner side of the plurality of magnet insertion holes to allow a fluid to flow through, and a shaft insertion hole in which a rotary shaft is inserted, and the permanent magnet inserted in each of the plurality of magnet insertion holes of the rotor core. The rotor core has an inlet opening and an outlet opening each opened in a corresponding one of end faces of the rotor core in an axial direction, and a communication hole circumferentially extending inside the rotor core and communicating with the inlet opening and the outlet opening.

Abstract: A vehicle electric machine may include a stator having end windings extending axially from the stator. A rotor may be disposed within the stator and including an endcap having an outer face defining outlets and a furrowed outer periphery with an edge configured to distribute coolant released from the outlets onto the outer face to different axial locations of the end windings during rotation. The furrowed outer periphery may taper toward an in inner flat portion. The outlets may be contained within the inner flat portion. The furrowed outer periphery may be symmetric about any axis perpendicular to and passing through an axis of rotation of the rotor. The outer face may further define channels extending from the outlets to the edge. The channels may be recessed in the outer face. The furrowed outer periphery may define concentric circumferential ridges.

Abstract: The rotor of the rotary electric machine according to the present invention includes: a cylindrical rotor core; magnets that are respectively housed in a plurality of magnet housing apertures that are formed circumferentially so as to pass axially through an outer circumferential side of the rotor core; and a rotor boss that includes: a cylindrical rotor ring that holds the rotor core; an annular mounting portion that is linked to the crankshaft so as to be disposed coaxially at a first axial end inside the rotor ring; and a linking plate that links the rotor ring and the mounting portion, and the linking plate is formed so as to have a curved shape that is convex toward a second axial end of the rotor boss, and has a thickness that reduces continuously from a radially inner side toward a radially outer side.

Abstract: The present disclosure relates to a plant for performing polymerization, such as the polymerization of ethylene, having a recycle connection with two or more cooling channels arranged in parallel, a process for polymerization and downstream processes, and a plant for polymerization, comprising the following plant components in fluid communication: a) A reactor with an inlet side and an outlet side; b) A recycle connection positioned in fluid communication between the outlet side of the reactor and the inlet side of the reactor; wherein the recycle connection comprises two or more cooling channels arranged in parallel.

Abstract: An axial flow fan having an axis of rotation includes a central hub including a base wall and a lateral wall which projects from the base wall to form a cup-shaped structure, a plurality of blades each fixed to the central hub and including a leading edge and a trailing edge, a plurality of extractors of a fluid which are associated with the base wall for conveying air from the inside of the cup-shaped structure to the outside of the cup-shaped structure through the base wall.

Abstract: A machine tool for cutting a workpiece with a cutting tool, includes a spindle motor that generates heat, a spindle head for supporting the spindle motor, and a heat insulating sheet disposed between the spindle motor and the spindle head. The area of a part of the heat insulating sheet that is in contact with a part of the spindle head having a high heat capacity is small so as to increase the amount of heat transferring from the spindle motor to the part of the spindle head having a high heat capacity, and thereby make the temperature distribution of the spindle head uniform.

Abstract: A synchronous generator, in particular a multipole synchronous annular generator of a direct-drive wind turbine, for generating electricity, with a rotor and a stator, wherein the stator has multiple grooves in which a stator winding is arranged, wherein the stator winding releases heat energy as a result of the generation of power, and wherein a cooling body for absorbing and dissipating released heat energy is arranged in one groove, multiple grooves or all of the grooves.

Abstract: A device for deflecting at least a portion of a cooling fluid flowing axially in an intermediate space is arranged between a rotor and a stator of a rotating electrical machine, in particular of a turbogenerator, wherein at least one blade can be arranged on a prespecifiable section of an outer face of the rotor and in the intermediate space, which blade is designed and can be arranged in such a way that a portion of the cooling fluid flowing in the intermediate space can be radially deflected in the direction of the stator by said blade.

Abstract: An induction motor may include a housing, a stator, a rotor, and/or cooling fins on an outside surface of the housing. The rotor may include inner air ducts configured to allow passage of airflow therethrough. The motor may include outer air ducts in fluid communication with the inner air ducts to form an air-circulation circuit. The outer air ducts may be arranged radially outside the cooling fins.

Abstract: Systems and methods are described for reducing friction within a transmission and an internal combustion engine including a PCV system. A gaseous fuel source is fluidly coupled to the transmission via a flow control valve and the transmission, in turn, is fluidly coupled to an air inflow line of the PCV system. The flow control valve is configured to control a flow of gaseous fuel into the transmission and there on into the PCV system and crankcase.

Abstract: An electric machine having a stator and a rotor arranged on an axis of rotation and a first fan, which extends in the radial direction on one section of the axis of rotation and delivers a coolant flow into the electric machine during operation. The electric machine further includes a fan directing element, which interacts with the first fan and deflects at least a proportion of the coolant flow. Variable and demand-based cooling of the electric machine can be achieved by the fan directing element, which can in particular be adjustable.

Abstract: An electric machine assembly, having a first machine providing an alternating current output and a second machine receiving a direct current input, and a rectifier assembly placed within a rotating shaft of the electric machine assembly to convert the AC output of the electric machine assembly to the DC input prior to transmission of the electricity from the electric machine assembly.

Abstract: The invention relates to an electric rotary machine including: a shaft of a rotor rotating about an axis, a fan carried by the shaft of the rotor, and a motor for driving the fan, allowing modulation of the relative rotational speed of the fan in relation to the shaft of the rotor.

Abstract: A rotating shaft is attached rotatably to a front body and a rear body of an AC generator. Feeding brushes are disposed around a rear end portion of the rotating shaft. A heat radiating plate is attached to a rear end of the rear body. A control board is attached to a back of the heat radiating plate. External air flows in from an air inlet and advances in a radially inward direction after passing through a cooling fin disposed on the heat radiating plate by a first air flow passage. In addition, the external air passes through and around the rear end portion of the rotating shaft after flowing into a rear surface side of the heat radiating plate via a second air passage.

Abstract: A blower wheel for setting a flow of air in circulation has vanes (2) that extend from a vane root attached to a hub (6) of the blower wheel. The hub (6) has a bottom wall (8) through which a through-orifice (12) for a drive shaft of the blower wheel passes, and a side wall (10). The hub (6) also has at least one rib (14) located between the orifice (12) and the side wall (10). The rib (14) is formed by one or more segments (14a, 14b, 14c, 14d). The segment, or one of the segments (14a, 14b, 14c, 14d), has at least one free edge (15) extending from the bottom wall (8) and facing toward the side wall (10).

Abstract: A drive device having an electric drive. A drive device (1) includes at least one housing (15), at least one electric drive, the electric drive having a rotor arrangement with a rotor shaft (7) which is designed for rotation about a rotational axis (17), and a bearing arrangement (14 a, b) for mounting the rotor arrangement. The bearing arrangement (14 a, b) supports the rotor arrangement in relation to the rotational axis (17) radially inwardly, the bearing arrangement (14a, b) supporting the rotor shaft in relation to a support section (15, 16) that is fixed to the housing.

Abstract: The electric rotating machine has the structure in which, for each one of the slots formed in its stator core, each of the innermost and outermost electrical conductors housed in the slot includes a R-chamfered portion formed in a bent portion thereof projecting outside from the slot and bent along a circumferential direction of the stator core. The R-chamfered portion is located at a radially inner or outer corner of the bent portion at which a side surface of the bent portion on the side being circumferentially bent intersects with a side surface of the bent portion on the radially inner or outer side. The R-chamfered portion is formed of a curved surface having a curvature radius larger than a curvature radius of the other three corners of the bent portion.

Abstract: The stator of the electric rotating machine includes a stator winding constituted of a plurality of U-shaped conductor segments each including a turn portion and two straight portions, the U-shaped conductor segments being connected in series by welding at welded portions formed in ends of the straight portions, and a stator core formed with slots, the straight portions of each U-shaped conductor segment being accommodated in corresponding two of the slots. The welded side slot pitch as an interval of the corresponding two of the slots on the side opposite to the turn portions is narrower than the N-S magnetic pole pitch of the rotor. The stator winding includes overlapped wire wrapping sections each constituted of the U-shaped conductor segments accommodated in the corresponding two of the slots, and crossover wires disposed on the side of the welded portions for connecting the overlapped wire wrapping sections.

Abstract: An electrical machine for an automotive vehicle has a housing (4). A stator arrangement (8) and a rotor arrangement (6) are disposed in the housing (4). At least one clearance (10) is formed in the housing (4) in proximity to the stator arrangement (8) and the rotor arrangement (6). A heat transmission device (12) is inserted into the clearance (10) as a prefabricated heat transmission module.

Abstract: According to one embodiment, a motor for a vehicle includes a casing accommodating a rotor and a stator iron core inside thereof, and supporting each of both axial ends of the rotor shaft via a bearing, an air inlet port formed in a portion of the casing outside the bearing in the radial direction, and a fan provided between the rotor iron core and the bearing and rotating with the rotor shaft, wherein a portion of the casing positioned outside impellers of the fan in the axial direction forms a first housing and a second housing constituting a discharge channel, and the first housing includes a guide wall extending toward the outside in the radial direction, and the second housing includes a thinned wall portion located inside the guide wall in the axial direction to constitute the discharge channel between the thin wall portion and the guide wall.

Abstract: A motor cooling system is provided comprising an electric motor including a rotor having first and second axial ends, and a stator having first and second axial ends, a motor housing surrounding the motor including an air chamber extending around the motor and axially along the motor length, a motor enclosure enveloping the motor housing, and a cooling fan radially mounted to the motor enclosure and adapted to operatively cool said electric motor.

Abstract: Provided is a cyclone type humidifier and wet air purifier combination device using centrifugal force. The humidifier and purifier combination device includes: a main housing; a blower fan provided under a main housing; a bottom housing which is coupled to the main housing and has an air blowing port, a water level sensor, an ultrasonic vibrator and a circular fixing plate; first and second filters which are disposed in the circular fixing plate; an outer cylindrical body which is coupled to the circular fixing plate and has a discharge pipe and an air inlet; an inner cylindrical body which is coupled to the circular fixing plate and includes an air guide body having a funnel shape with an impurity discharge hole; and an air guide housing configured.

Abstract: In one embodiment, an electric motor. A first bracket is fixed to the first side of a stator core in an axial direction, and is fixed to first bearing housing. A second bracket is fixed to the second side of the stator core, and is fixed to second bearing housing. The rotor includes a shaft rotatably supported by bearings, and an attached rotor core. Rotor core faces the inside of the stator core. A fan is attached to the shaft between the rotor core and the first housing. A flue formed between the first housing and the first bracket is configured to draw air from a port to a part of the first bracket. A rotation detection circuit includes a detected part fixed to the fan, and is within the flue. A sensor operable to detect the part is set in the flue, counter to the detected part.

Abstract: A hybrid module (1) is installed a drive train of a motor vehicle between a combustion engine and a transmission and has an electric machine and a clutch installed in a common housing (2). The hybrid module (1) further has an air supply entrance (7) for introducing cooling air into the hybrid module (1). The air supply entrance (7) is an oval with a short axis directed toward the combustion engine and the transmission. Thus, the hybrid module has a short extent between combustion engine and transmission, and also allows a sufficiently large quantity of air to be supplied into the hybrid module.

Abstract: A brushless alternator has a housing with a front portion and a rear portion. A stator assembly, rotor assembly, and coil support are positioned within the housing. The coil support has a shank portion of a first outer diameter and a base portion of a second outer diameter greater than first outer diameter. The base portion includes a plurality of air flow openings that extend through a second sidewall. A rectifier and regulator assembly is positioned on the outside of the rear portion of the housing. A front fan circulates air across the stator assembly at the front portion of the housing. A rear fan creates a cooling flow of air through flow openings of the coil support to circulate air across the regulator and rectifier assembly and the stator assembly.

Abstract: The rotating electric machine is configured in such a way that a surface of the heat sink, on which the cooling fins of the heat sink are formed, faces the housing; and a plate, which blocks the surface of the housing facing the heat sink and forms a wind passage between the heat sink and the plate, intervenes between the cooling fins and the surface of the housing facing the heat sink; and outside air is aspirated from an inlet formed on the protective cover, and then, the outside air is passed through the wind passage formed between the heat sink and the plate so as to be passed through a window formed on the housing, and is exhausted, by the cooling fan of the rotor, from an outlet formed on the housing.

Abstract: A working tool in which a tip tool with a longitudinal shaft is linearly moved, wherein a motor and other tool constituting members are effectively cooled. In order to cool the inside of a motor-driven hammer comprising a main body, a motor, and a motion converter, the hammer is provided with a first cooling air passage through which a cooling air is supplied to the motor, and a second cooling air passage through which a cooling air is supplied to a hammer portion. To generate a cooling air to be supplied to the first and second cooling air passages, a cooling fan is provided at a lower portion of an output shaft of the motor and a hammer portion cooling fan is provided between the output shaft of the motor and the motion converter.

Abstract: A rotating electrical machine includes a rotor which has a rotor core formed by stacking magnetic plates having an annular plate shape in an axial direction, a permanent magnet is inserted into a magnet insertion hole formed in the rotor core, and a rotor shaft is inserted into a shaft insertion hole surrounded by an inner peripheral surface of the rotor core; and a stator. A radial communication passage is formed by a communication penetration hole group that is formed by sequentially communicating a plurality of the penetration holes from a shaft insertion hole to a magnetic resistance hole in the radial direction. The plurality of the penetration holes are divided into at least two specific magnetic plates and formed such that the radial positions of the penetration holes are different from each other and the penetration holes partially overlap each other when viewed in the axial direction.

Abstract: A stator coil includes first to fourth in-slot portions and first and second turn portions. Both the first and third in-slot portions are received in one slot of a stator core, while both the second and fourth in-slot portions are received in another slot. The first and second turn portions both protrude from an axial end face of the stator core and respectively connect the pair of the first and second in-slot portions and the pair of the third and fourth in-slot portions. The second turn portion is located inside the first turn portion. When viewed along an axial direction of the stator core, the first and second turn portions extend so as to cross each other with a reference line C interposed therebetween; the reference line C is defined to extend along a circumferential direction of the stator core through an intersection between the first and second turn portions.

Abstract: Embodiments of the invention provide an electric machine module including an electric machine which can include a stator assembly. The stator assembly can include stator end turns. Some embodiments can provide a housing at least partially enclosing the electric machine and the housing can at least partially define a machine cavity. Further, at least one baffle can be coupled to the housing at a region near the stator end turns, so that the at least one baffle surrounds a portion of a perimeter of the stator end turns.

Abstract: Disclosed is an end cap for a motor housing containing an electric motor, including a tubular structure defining an interior space, including an open first end connectable to the motor casing; a second end, including a first planar surface; a second planar surface offset from the first planar surface and substantially parallel to the first planar surface; and at least one air grate surface substantially perpendicular to the first planar surface and the second planar surface, positioned between and attached to the first planar surface and the second planar surface, and wherein the at least one air grate surface includes at least one air grate configured to permit air flow into and/or out of the interior space.

Abstract: A cooling structure of a rotating electric machine includes a rotor core formed of a plurality of electromagnetic steel plates and a resin molding portion molding the rotor core with resin. The rotor core is provided with a through hole passing therethrough in the axial direction of the central axis that is a rotation axis. The rotor core is provided inside the through hole with an oil passage through which oil circulates. The resin molding portion has a cover portion covering the outer peripheral side of the oil passage. This configuration can provide the cooling structure of the rotating electric machine that achieves efficient cooling while suppressing occurrence of energy loss.

Abstract: The totally-enclosed fan-cooled motor includes the stator; the rotor; the drive side bracket; the counter drive side bracket; a pair of the bearings; the external fan that sends cooling air to the stator; the internal fan; the heat radiator that is arranged on an outer side of the drive side bracket and is mounted on the rotation shaft; the cover that contains a joint, which connects the rotation shaft extending to an outer side of the drive side bracket of the motor and a reduction gear, and is provided in parallel with the joint; and the ventilation path that is arranged between the drive side bracket and an end of the cover, and includes the outlet causes the cooling air induced by rotation of the heat radiator to flow to the heat radiator and discharges the cooling air outside the motor.

Abstract: There is provided an open-type induction motor, and more particularly, to an open type induction motor in which a rotor has a structure allowing air to flow therein, thus enhancing cooling efficiency of the rotor and a stator. The open-type induction motor includes: a stator including an iron stator core having a radial duct hole and a stator coil wound around the iron stator core; and a rotor disposed in a hollow of the stator so as to be rotatable by magnetism generated by the stator coil, and including a rotational shaft, a plurality of iron rotor cores stacked in an axial direction of the rotational shaft and coupled to the rotational shaft, a rotor coil coupled to the plurality of iron rotor cores, and duct plates stacked between the plurality of iron rotor cores and outwardly discharging air present at the inner side of the iron rotor cores.

Abstract: A fan motor apparatus having an improved heat-radiation performance includes a stator including an electronic device; a central shaft which is fixed onto the upper surface of the stator; a rotator mounted rotatably with the respect to the stator by being rotatably coupled to the central shaft; a heat-radiating fin portion provided on an inner surface of the rotator to generate wind toward the stator when the rotator rotates; and an cooling fin combined air flow guide formed on a surface of the stator to increase a heat exchange area for a heat exchange between the air generated by the heat-radiation fin portion and the air inside the stator; and at the same time guide the air from the exterior of the stator toward the central shaft so that the air is introduced into the rotator via a lower surface of the rotator.

Abstract: Certain embodiments provide systems and methods for cooling a drive end bearing. The system may include an alternator including a drive end bearing, a drive end fan and a front housing face. The drive end fan may include a shaft aperture and auxiliary air flow inlet apertures positioned circumferentially around the shaft aperture. The front housing face may include auxiliary fins coupled to the drive end bearing. The auxiliary fins may protrude from the front housing face. The auxiliary fins may be arrayed axially on the front housing face. In various embodiments, the drive end fan is rotated to draw air through the auxiliary air flow inlet apertures and adjacent to at least a portion of auxiliary fins of the front housing face. The at least a portion of the auxiliary fins transfers heat from the drive end bearing to the air.

Abstract: Vent spacers and induction motor rotor core assemblies for induction motors are disclosed. The induction motor rotor assembly includes at least two rotor packages, each having axial sidewalls, a radial periphery, and axial vents, and a vent spacer positioned between opposing axial sidewalls of the at least two rotor packages. The vent spacer has a hub and a plurality of radially-extending fins coupled to the hub, the fins extending approximately to a radial periphery and extending axially between the opposed axial sidewalls to form a plurality of radial cooling channels extending between the sidewalls. Induction motors and methods of operating the induction motors are disclosed, as are other aspects.

Abstract: A main stator sleeve for a generator includes a sheet of material that includes an arcuate notch one two opposed edges such that a butt joint therebetween defines a pin aperture.

Abstract: A rotor having a plurality of laminations joined together and mountable on a shaft for rotation relative to a stator of a rotary electric machine arrangement has a solid section that surrounds an opening within which the shaft is receivable. The solid section includes an outside diameter, magnet receiving voids, and steps delimiting a plurality of pole spans from flux directing features at sides of each of the pole spans. Adjacent flux directing features between adjacent pole spans are disposed on opposite sides of scalloped areas or other such recesses, permitting cooling air flow past the rotor. The invention also concerns a lamination usable together with additional laminations to provide such a rotor, as well as an arrangement, such as an AC motor, generator, or motor/generator, including a stator and such a rotor.

Abstract: An electric motor with a stator housing (2) and with an electronics housing (8), has a first section (A) of the electronics housing arranged on the radial side of the stator housing (2), and a fan (24) arranged on a first axial end (22) of the stator housing (2). The electronics housing (8) extends in the axial direction (X) beyond the first axial end (22) of the stator housing in a manner such that a second section (B) of the electronics housing (8), in whose inside at least one first heat-producing electronic component (58, 60) is arranged, is situated on the radial side of the fan (24). A pump assembly with such an electric motor is also provided.

Abstract: A rotor core includes magnet insertion holes embedding permanent magnets and arranged in a substantially U-shape, facing an outer circumferential surface of a rotor, and includes hollow portions formed at both side surface portions in a direction orthogonal to a magnetization direction of the permanent magnets embedded in the magnet insertion holes. A permanent magnet group for each pole having the plurality of permanent magnets includes vent holes passing through the rotor core in a direction of a rotating shaft, between one of the magnet insertion holes in which the permanent magnets are embedded and adjacent one of the magnet insertion holes or between the one of the magnet insertion holes and outer circumferential portions of the rotor core. The vent holes are arranged at positions to form the substantially U-shape together with the magnet insertion holes.

Abstract: The method for rewinding and electric machine includes removing the original stator bars from the slots, removing the original supports from the slots, and providing new supports into the slots, wherein the new supports defining cooling channels that extend over at least a portion of the slot, providing new stator bars into the slots.

Abstract: Embodiments of the invention provide an electric machine module. The module can include a housing, which can define a machine cavity. In some embodiments, a coolant jacket can be at least partially positioned within the housing. In some embodiments, a plurality of coolant apertures can be disposed through at least a portion of the housing to fluidly connect the coolant jacket and the machine cavity. The coolant apertures can include a first group configured and arranged to direct a first volume from the coolant jacket. The coolant apertures can include a second group configured and arranged to direct a second volume from the coolant jacket. In some embodiments, the first volume can be greater than the second volume.

Abstract: Electric generator is disclosed having a stator and a rotor. The rotor being rotatable around a center axis and relatively to the stator and the stator includes a number of stator windings extending in freely exposed end windings. The stator and/or the rotor is provided with at least one barrier means which barrier means axially extends to such a manner that at least the end windings of the stator are at least partially covered.

Abstract: An electric machine can include a stator, a rotor frame and a pole arrangement with: plural segment pieces disposed circumferentially around, and fastened to, the rotor frame; permanent magnet pieces positioned on inclined side edges of each segment piece; and plural pole pieces disposed circumferentially around the rotor frame and disposed alternatingly with the segment pieces. The magnet pieces are pressed between inclined side edges of the pole pieces and the inclined side edges of the segment pieces. The segment pieces, the permanent magnet pieces and the pole pieces form a closed ring around the outer surface of the rotor frame, with plural such rings being arranged after each other in an axial direction. An axial air channel can pass through the rings, and at least one radial air duct (R1, R2) between the rings.

Abstract: An electrical device and servo motor that includes a stator having a plurality of poles, wherein each pole includes a first surface and a second surface; the first surface and the second surface are spaced apart and have a pair of slots defined between the first surface and the second surface on respective sides of each pole. The pair of slots is configured to receive at least one winding, and each pole further includes a cooling tube coupled to the first surface, wherein the cooling tube is at least partially encompassed within the first surface.

Abstract: A system for cooling an electric motor, the electric motor including a stator disposed about a rotor, wherein cooling system includes a rotor assembly including a shaft with a shaft channel extending through the center of the shaft and radial channels extending radially from the shaft channel; a rotor with profiled rotor ends; and two guides, each coupled to a rotor end, that guides fluid from the shaft exterior to the rotor end. The system may additionally include interior channels that traverse through the rotor interior, wherein the interior channels fluidly couple the radial channels to a guide-rotor end pair. The system may also include stator cooling mechanisms, including cooling channels within the motor casing proximal to stator exterior surface and dispensing mechanisms that dispense working fluid to the stator coils.

Abstract: A first cooling air passage is formed to let first cooling air generated by a cooling fan in from a radially outside of an inverter apparatus to cool a heat sink and out through exhaust holes provided on an outer peripheral side of a rear bracket by passing an inner periphery of the rear bracket. Also, a second cooling air passage is formed to let second cooling air generated by the cooling fan into a hollow portion of the inverter apparatus from an axially rear of a rotation shaft to cool a brush holder and a magnetic pole position detection sensor and out through the exhaust holes by passing the inner periphery of the rear bracket. Hence, cooling performance for the magnetic pole position detection sensor and the brush holder may be enhanced and an axial dimension may be reduced.