Abstract: A fan mounting apparatus for dissipating heat from an electronic device, the mounting apparatus includes a bracket (50) and a fan module (40). The bracket defines an opening (57), two vertical slots (59) at opposite sides of the opening and two fixing holes (58) under the slots and aligned with the respective slots. The fan module includes a fan (10) and a pair of clamping members (30). The pair of clamping members respectively attached to opposite sides of the fan, an engaging portion (35) formed on each clamping member for engaging with the corresponding slot of the bracket, and each engaging portion has a sliding portion (351) and a clamping portion (353), wherein each sliding portion is capable of being received in the corresponding slot, and the clamping portion engaging with the fixing hole.

Abstract: A portable electronic device includes a casing, an electronic component disposed in the casing, and a thermal module for dissipating heat of the electronic component. The thermal module includes a heat pipe, a fin unit, and a transverse fan. The heat pipe includes an evaporating section thermally attached to the electronic component, and a condensing section thermally attached to the fin unit. The transverse fan is arranged in the casing for generating an airflow through the electronic component and the fin unit. The transverse fan includes a rotor, and a sidewall on a floor of the casing and surrounding the rotor. The sidewall defines an air inlet and an air outlet therein. The air outlet faces to the fin unit. The air inlet faces to the electronic component.

Abstract: A mid-turbine frame connected to at least one mount of a gas turbine engine transfers a first load from a first bearing and a second load from a second bearing to the mount. The mid-turbine frame includes a plurality of inverted panels and a plurality of struts. The inverted panels convert the first and second loads to a shear flow. The struts are connected to the inverted panels and transfer the shear flow to the mount.

Abstract: A guide vane arrangement of a turbomachine includes a casing, at least one guide vane carrier connected to the casing and having a first carrying portion and a second carrying portion spaced apart axially from the first carrying portion, a plurality of guide vanes connected to the guide vane carrier and arranged next to each other in a circumferential direction, and at least one securing element connected to the guide vane carrier and configured to provide an axial fixing of at least one of the guide vanes. Each guide vane has a platform including a first locking portion and a second locking portion spaced apart axially from the first locking portion, wherein each of the first and second locking portions and the respective first and second carrying portion are adapted to provide an axially pluggable and a radially positive fastening between the guide vane carrier and the respective guide vane.

Abstract: A fan for easily being attached to a fixing device and includes a fan body and a frame for holding the fan body therein. The frame includes two parallel first sidewalls, and two parallel second sidewalls perpendicular to the first sidewalls. Two pairs of rims symmetrically extend from the first sidewalls and the second sidewalls. Ends of the rims on the first sidewalls toward one same second sidewall each include a latch flange. Ends of the rims on the second sidewalls toward one same first sidewall each includes a latch flange. Each of the latch flanges includes a guiding edge slantingly extending from the corresponding rim, and a latch edge perpendicular to the corresponding rim. Each of the latch flanges includes a guiding edge slantingly extending from the corresponding rim, and a latch edge perpendicular to the corresponding rim.

Abstract: A fan assembly for an electronic device is provided. The assembly comprises a fan housing, at least one bracket member, and at least one retention peg. The fan housing defines a recess therein for directing heat away from a electrical components positioned within the electronic device. The bracket member supports the fan housing within the electronic device. The retention peg is disposed about the bracket member and includes a plurality of ribs for insertion into the recess to retain the bracket member to the fan housing.

Abstract: A motor mount assembly for an air cleaner is provided according to an embodiment of the invention. The motor mount assembly includes a motor ring adapted for receiving a motor, a mount ring adapted to be received in the air cleaner, and a plurality of mounting vanes extending between the motor ring and the mount ring. A mounting vane of the plurality of mounting vanes includes a proximal end and a distal end. The distal end is affixed to the motor ring and the proximal end is affixed to the mount ring.

Abstract: A mounting apparatus is used to mount a fan having a bottom panel with a mounting hole defined therein. The mounting apparatus is configured to support the bottom panel on a top side thereof. The board forms a clip on the top side of the board, and defines a through hole adjacent the clip. The clip includes a elastic shank standing on the top side of the board, a flange formed on a top end of the shank and suspended over the shank, and a driving pole extending downwards from the shank and through the through hole of the board to have a driving end of the driving pole located below the board adapted to bend the shank. The clip is inserted in the mounting hole of the bottom panel with the flange engaging on a top surface of the bottom panel. The bottom panel is sandwiched between the flange and the top side of the board. The driving end of the driving pole is manually bendable to disengage the flange of the clip from the top surface of the bottom panel.

Abstract: Twin-flow turbo-jet engine, comprising a cylindrical casing externally defining an annular flow space for a secondary flow, wherein the cylindrical casing is formed from a lattice framework and from removable cowling panels fixed to the framework, said framework comprising an upstream annular flange for fixing to an intermediate housing, a downstream annular flange for connecting to an exhaust housing and rigid beams parallel or inclined relative to the axis of the turbo-jet engine, connecting the two flanges to one another.

Abstract: A heat accumulation segment for local separation of a flow duct inside a turbo engine, from a stator housing that radially surrounds the flow duct is provided. The heat accumulation segment includes two axially opposed joining contoured elements that are engagable with two components that are axially adjacent along the flow duct. A first one of the two joining contoured elements has a radially oriented recess with a contoured surface against which a securing pin having an external contour complementary to the contoured surface acts radially under force action from a component that adjoins the first joining contoured element. The first joining contoured element has a collar portion having radially upper and lower collar surfaces, and the collar portion is connected within a counter-contoured receiving contoured element in the axially adjacent component by a joining force that acts between the securing pin and the conical contoured surface.

Abstract: Exemplary embodiments of the present invention are directed towards an apparatus and method for fluidly coupling a turbocharger to an internal combustion engine. In one embodiment, a turbocharger mount for fluidly coupling a turbocharger to an exhaust system of an engine is provided. The turbocharger mount includes a housing portion and a mounting flange extending from the housing portion. The housing portion defines a cavity therein and a first inlet opening in fluid communication with the cavity, a first outlet opening in fluid communication with the cavity, and a second outlet opening in fluid communication with the cavity.

Abstract: The nacelle (1) comprises an air intake (5) upstream of the turbojet engine (2), a middle section (6) an internal casing (6a) of which is intended to surround a fan (3) of the turbojet engine (2), and a downstream section (7) comprising an external structure (7a)which is rigidly connected to a downstream part of the casing (6a) of the fan (3) so as to support the turbojet engine (2) and has means of attachment to a strut (12) intended to be connected to a fixed structure (13) of an aeroplane.

Abstract: A casing 10 of a pump has first and second casing elements 20, 30. Each of the casing elements has a mating face and these mating faces are sealingly joined. An interior of the first casing element defines a portion of a chamber 50 in which the impeller is mounted. A first interior portion of the second casing element defines the remaining portion of the impeller chamber, and a second interior portion defines a diffusion chamber 60 that is in fluid communication with the impeller chamber. Fluid entering the casing at a fluid inlet 34 passes into the impeller chamber, where velocity is imparted to the fluid. The velocity-enhanced fluid passes axially into the diffusion chamber, which has an expanding cross-sectional area along its length, to convert the velocity into pressure head, which is achieved increasing by at least one of: the radially-inward width and the axial height.

Abstract: The invention provides a casing, equipment unit, fan unit and electronic equipment capable of easily implementing assembling, disassembling, attaching and so forth without using fixture components, tools, and so forth. The structure is made up of casing sections, hinge parts and a coupling part. The casing sections are made up of not less than two sections and enclosing a hosing space, and members for securing the housing space thereby. The hinge parts are members coupled with the casing sections and supporting each casing section. That is, not less than two casing sections couple the edge parts of each casing section, and bendably support each casing section. The coupling part is a member for restraining the casing sections positionally and maintaining and fixing the housing space. That is, the coupling parts detachably couple each casing section to hold the housing space on each casing section.

Abstract: A computer system comprises a chassis, an electronic component disposed within the chassis, and a cooling fan that comprises a motor support fixed to a housing that is coupled to the chassis and a hub disposed within the housing. A plurality of blades extend radially from the hub. A motor is disposed within a motor enclosure formed by the motor support and the hub. The hub is rotatably coupled to the motor such that the plurality of blades generates a flow of air around the motor enclosure. The system comprises a motor cooler comprising a flow path through the motor enclosure, where the flow path has a first opening and a second opening, and where the second opening is disposed within an area of lowered downstream pressure so as to develop a differential pressure between the first and second openings and generate a flow of air through the motor enclosure.

Abstract: A heat accumulation segment for local separation of a flow duct inside a turbo engine, from a stator housing that radially surrounds the flow duct is provided. The heat accumulation segment includes two axially opposed joining contoured elements that are engageable with two components that are axially adjacent along the flow duct. A first one of the two joining contoured elements has a radially oriented recess with a frustoconical contoured surface against which a securing pin having a frustoconical external contour that acts radially under force action from a component that adjoins the first joining contoured element, and the first joining contoured element has a collar portion having a radially upper collar surface and a radially lower collar surface. The collar portion is connected within a counter-contoured receiving contoured element in the axially adjacent component by a joining force that acts between the securing pin and the frustoconical contoured surface.

Abstract: A fan structure is disclosed to include a fan holder holding a fan motor and a fan blade, a bottom cover frame, which has smoothly arched bottom wall, a horizontal mounting flange extending around the smoothly arched bottom wall and mounted in one frame sash of a light steel structure of a ceiling, a vertical connection flange connected to the top cover shell of the fan holder, a circular center opening corresponding to the fan blade, ventilation holes spaced around the circular center opening and a fence disposed above the circular center opening and surrounding the fan blade defining with the top cover shell of the fan holder a space for causing a gate effect during rotation of the fan blade, and a grille mounted in the circular center opening of the bottom cover shell for output of currents of air caused by the fan blade.

Abstract: What is described is a turbine guide vane having a guide vane leaf and with a radially outer platform connected to the guide vane leaf and having a platform surface which faces radially away from the guide vane leaf and on which a connecting structure is provided for fastening the guide vane to a supporting structure which has side wall portions which project radially beyond the platform surface and delimit an inner cavity and on which is provided at least in portions a joining contour which can be inserted into a reception shape countercontoured within the supporting structure. At least one seal is provided between the connecting structure and the supporting structure.

Abstract: A heat dissipation device for at least a heat-generating electronic component includes a heat sink, a fan for providing an airflow through the heat sink and a fan holder coupling the fan to the heat sink. The heat sink has a first locking part and a second locking part opposite to the first locking part. The fan holder has a first engaging part engaging with the first locking part at one side of the heat sink and a second engaging part engaging with the second locking part of the heat sink at an opposite side thereof. The first engaging part has a horizontally extending fixing arm and a barb extending downwardly from the fixing arm and hooking with a top side of the heat sink.

Abstract: The turbine casing includes a circumferential wall coaxially surrounding a ring that surrounds the moving blades of the turbine. The casing includes a plurality of perforations delivering air for ventilating the outside face of the circumferential wall in uniform manner.

Abstract: An assembling member and a heat-dissipating module having the assembling member are proposed. The assembling member connects a fan having at least a receiving space and a plurality of first positioning portions to an electronic host housing having a plurality of first fixing portions. The assembling member includes a main body for being accommodated into the receiving space, a plurality of first coupling portions for coupling with the first positioning portions, an elastic portion disposed at one side of the main body, and a plurality of first engaging portions for engaging with the first fixing portions. The first engaging portions are connected to the elastic portions, such that the first engaging portions can be urged by the elastic portions of the assembling member to engage with the first fixing portions. The heat-dissipating module of the present invention is easy to assemble and disassemble, has simple structure and low cost.

Abstract: A turbocharger system for an internal combustion engine includes a turbocharger with a utility pedestal extending between the turbocharger and the hard point associated with the cylinder block. The utility pedestal includes a mounting pad for attaching the combined turbocharger and pedestal assembly to an engine, as well as oil and coolant supply passages for supplying the turbocharger with coolant and lubricating oil under pressure. An internal, isolated, turbocharger oil drainback passage conducts waste oil from the turbocharger to a crankcase sump without permitting the waste oil to contact the engine's moving parts.

Abstract: A turbocharger system for an internal combustion engine includes a turbocharger with a utility pedestal extending between the turbocharger and a mounting point associated with the cylinder block. The utility pedestal includes a mounting pad for attaching the combined turbocharger and pedestal assembly to an engine, as well as oil and coolant supply passages for supplying the turbocharger with coolant and lubricating oil under pressure. The utility pedestal's fastening system is configured so as to cover a minimum amount of space of the engine surface to which the pedestal is mounted, so as to reduce the footprint of the turbocharger system.

Abstract: A turbocharger system for an internal combustion engine includes a turbocharger with a utility pedestal extending between the turbocharger and a mounting surface associated with the engine. The utility pedestal includes a mounting pad for attaching the combined turbocharger and pedestal assembly to the engine, as well as internal oil and coolant supply passages for supplying the turbocharger with coolant and lubricating oil under pressure.

Abstract: A heat dissipation device for dissipating heat from a heat-generating electronic element includes a heat sink for contacting with the heat-generating electronic element, a fan placed on the heat sink for providing an airflow through the heat sink and two wire clips. The fan comprises a frame. Each wire clip comprises a V-shaped main body and two locking parts at two opposite ends of the main body. Middles of the main bodies of the two wire clips are securely attached to two lateral sides of the heat sink by two screws. The locking parts of the wire clips are fastened to the frame of the fan, with the main bodies being deformed and pushing the fan toward the heat sink.

Abstract: The invention relates to an exhaust-driven turbocharger (1) for a motor vehicle, with a bearing housing (2) and a turbine housing (3), a turbine wheel (18) and a compressor wheel, which are mounted in the bearing housing (2) by means of a common shaft, a guide vane cage (9), which surrounds the turbine wheel (18) with a defined gap, Essential to the invention is that the guide vane cage (9) has at least two arms (10), by means of which it is clamped between the bearing housing (2) and the turbine housing (3) in such a manner that it can only move in the radial direction, so that the guide vane cage (9) can expand in a stress-free manner in the radial direction (16).

Abstract: An aircraft engine assembly including an engine, an engine mounting structure, and a nacelle surrounding the engine and including an air intake and fan cowls. The assembly further includes a cradle supporting the fan cowls, fixedly mounted on the mounting structure or else on an entity including a fan case and the air intake attached to the case. The engine assembly further includes a junction aerodynamic fairing including a first mounting mechanism mounted on the cradle, and including a second mounting mechanism mounted on the other of the elements from among the mounting structure and the entity.

Abstract: A multi-functional air circulation system includes a bottom base, a flow-splitting base, a filter and a main engine. The bottom base has a lower flow-guiding surface, a net, and a space used to contain diverse improving agents. The flow-splitting base is fixed on the bottom base, including an inner flow-guiding surface to rush air flow generated by a blade member down to the bottom base. The filter is laid at an exit of the inner flow-guiding surface, composed of two filter bases forming a room between them for containing aromatic powder, etc. The main engine includes a motor having its shaft fixed with a blade member, and a control system. The motor is installed in a rear shell combined with a front shell. Air is sucked in through the rear shell to run through an ornamental shell and the flow-splitting base to enter a room. The main engine and the bottom base can also be assembled to work independently.

Abstract: A mounting system for mounting a rotary member to a stationary member. The mounting system includes a carrier adapted to engage the rotary member, wherein the carrier includes a mounting leg portion which terminates into a pair of resilient leg portions. The carrier may also further include a spring member adapted to engage a first surface of the stationary member. At least one of the legs in the pair of resilient leg portions includes a turned-out portion adapted to engage a second surface of said stationary member.

Abstract: A mounting apparatus is provided for securing a fan. The fan has four corner portions projecting from two opposite sides thereof, the corner portions each define a mounting hole therethrough. The mounting apparatus includes a bracket for securing the fan therein, and two locking members. The two locking members each comprise a pivoting portion and a positioning portion spaced from the pivoting portion. The pivoting portion and the positioning portion respectively form a pivoting post and a positioning stub to respectively engage two of the mounting holes of one side of the fan, the fan and the two locking members are secured within the bracket.

Abstract: A heat dissipation device includes a fan (200), a first wire collection structure (280) and a second wire collection structure (290). The fan (200) includes a frame (210) and an impeller (240) disposed in the frame (210). The first wire collection structure (280) is formed on the frame (210) to collect wires (270) of the fan (200). The second wire collection structure (290) is formed on the frame (210) and configured for collecting wires (460) of another component other than the fan (200).

Abstract: A fan frame includes a main body (10) and conducting wires (40) secured on the main body. The main body has a securing tab (30) extending from an outer surface thereof. The securing tab has a free end. A groove (32) for the wires to extend through is defined between the securing tab and the outer surface of the main body. At least a block (35) extends from the outer surface of the main body. A space (80) for receiving the wires therein is defined between the block, the securing tab and the outer surface of the main body. A guiding surface (352) is formed on the block from a bottom end towards a top end of the block for guiding the wires to move into the space.

Abstract: A method of operating a gas turbine engine is provided. The method includes channeling cooling air towards a shroud hanger assembly such that the cooling air flows through a cavity defined in the shroud hanger assembly, directing the cooling air through a plurality of cooling passages extending from the cavity, and discharging the air from the plurality of cooling passages towards an impingement baffle to facilitate cooling a shroud hanging from the shroud hanger.

Abstract: A miniature fan arrangement has a fan (10) including an electronically commutated drive motor (21), a first circuit board (52) associated with said motor, and a fan housing (30). The fan also has a mounting part arranged radially outside the fan housing (30), and has a membrane (32), made of an elastic material, that elastically connects the fan housing (30) and the mounting part (34) to one another. A second circuit board (54) is arranged between the mounting part (34) and the fan housing (30) and is electrically connected to the first circuit board (52). The structure provides space for additional motor control components, particularly in small-sized motors.

Abstract: A rear fan case for a gas turbine engine includes a main body and a discrete joining arrangement mounted on the outside of the main body towards its rear end. The joining arrangement provides a substantially radial groove around the main body, which can receive a joining blade on a thrust reverser unit to form a joint between the rear fan case and the thrust reverser unit. The joining arrangement may be made of metal while the main body is made of composite material. Features may be provided to ensure proper alignment and location of the joining arrangement.

Abstract: A fan module adapted to be assembled onto a system frame includes a body, a fan assembly, and at least two connecting elements. The body has an accommodating space. The fan assembly is disposed in the accommodating space. The connecting elements are protruded from the body, and the connecting elements are inserted to and connected with a plurality of holes of the system frame.

Abstract: A fan frame (20) includes a bracket (22) and a base (24). The bracket includes a sidewall (225). An air inlet (228) is defined in a top side of the sidewall. An opposite air outlet (229) is defined in a bottom side of the sidewall. A plurality of first locking units (227) are formed on the sidewall. The base includes a main body (240), a plurality of ribs (242) and a plurality of second locking units (245). Each rib has a fixed end (2421) connected with the main body, and an opposite free end (2422). Each second locking unit is formed at the free end of a corresponding rib. The second locking units are detachably interlocked with the first locking units to mount the base to the bracket thereby to form the fan frame. The bracket and base are formed by materials having different strengths.

Abstract: A stack of fan case in accordance with the present invention includes a first casing and a second casing stacked on the first casing. The first casing has a first surface, a second surface and a locking surface opposite to the second surface. An insertion bore formed on the second surface penetrates the second surface and the locking surface and has an alignment bore, a fastening bore communicating to the alignment bore and a limit bump formed at the fastening bore. The second casing has a third surface, a fourth surface and at least one fastening member protruding on the fourth surface. The fastening member includes a stick-like portion and a limit clasp portion formed at one end of the stick-like portion.

Abstract: The invention relates to a steam turbine, in particular for a power plant, comprising an outer casing, an inner casing arranged in the outer casing, and a plurality of guide blade rows. In order to reduce leakage flows in the inner casing, a blade ring is provided, which is arranged in the inner casing and in which at least some of the guide blade rows are arranged.

Abstract: An engine casing assembly having dual load transfer points includes a U-shaped mid-turbine frame, an engine casing, a plurality of dimples, a strut and a mounting apparatus. The engine casing has an exterior surface and an interior surface. A plurality dimples are formed in the engine casing so that U-shaped protrusions are formed in the interior surface and U-shaped indentions are formed in the exterior surface. A strut connects one U-shaped protrusion to the mid-turbine frame and a mounting apparatus located within an indention so that a load is transferred from the mid-turbine frame to the engine casing and the mounting apparatus.

Abstract: An engine casing for a mid-turbine frame having a plurality of radially extending struts includes a ring structure and at least one mount. The ring structure has an interior surface, an exterior surface, and a plurality of equally spaced dimples along the exterior surface and protruding from the interior surface. The ring structure is connected to each of the plurality of struts at the interior surface at the dimples. The mount is positioned within each of the dimples and transfers load to the engine casing.

Abstract: Gas turbine engine systems involving fairings with locating data are provided. In this regard, a representative a fairing assembly for a gas turbine engine includes: a first locating component having a leading edge, first and second sides extending from the leading edge, and a recess oriented parallel to the leading edge, the recess having a first datum surface, the first locating component being operative to be positioned between a portion of a strut and a portion of an interior surface of a fairing sheath such that the first datum surface establishes a desired orientation of the fairing sheath relative to the strut.

Abstract: A fan module, including a housing for receiving a fan, a connector configured to mate with a connector housing, and a vibration pad configured to isolate vibrations of the fan from transferring through the fan module, wherein the fan module is configured to receive an alignment attachment standoff.

Abstract: A method of assembling a turbine engine is provided. The method includes providing a bushing including at least one retaining mechanism formed integrally therewith, coupling a shim to the bushing such that at least one retainer extending from the shim is received within the bushing retaining mechanism, and coupling the bushing and shim within the turbine engine to facilitate aligning a first engine component relative to a second engine component.

Abstract: A composite fan frame includes a first frame and a second frame. The first frame has a first surface formed with at least one first protrusion portion. The second frame has a second surface formed with at least one first recess portion. When the first surface touches the second surface, the first protrusion portion is inserted into the first recess portion along a predetermined sliding direction such that the first frame and the second frame are combined. Also, a composite fan having the composite fan frame is disclosed.

Abstract: A frame for a serially connected axial flow fan unit includes a first housing and a second housing coupled together. The first housing includes a first axial locking mechanism and a first unlocking mechanism, and the second housing includes a second axial locking mechanism and a second unlocking mechanism. The first and the second axial locking mechanism are locked against each other through their movement along their axis. The first and the second unlocking mechanism unlock the first and the second housing with a twisting force equal to or greater than a predetermined value when the first and the second housing are twisted relative to each other. When the first and the second end portion are brought into contact, the first and the second axial locking mechanism are locked against each other and the first and the second unlocking mechanism engage with each other.

Abstract: A fan bay and fan coupling apparatus include a chassis including a plurality of fan bay locating features and a plurality of fan connectors. A fan bay includes a plurality of chassis locating features and defines a plurality of fan assembly housings, wherein the chassis locating features on the fan bay are engageable with the fan bay locating features on the chassis. A plurality of fan assemblies each include a fan, wherein a fan assembly is located in each of the fan assembly housings, whereby the engagement of the chassis locating features on the fan bay with the fan bay locating features on the chassis allows the alignment and coupling of the plurality of fan assemblies with respective fan connectors on the chassis.

Abstract: An equipment fan has a housing (100) which is configured as a plug-in module for an equipment rack. The housing has a front side (102) and a back side (104), the latter being slid into the equipment rack (320) first upon installation. For latching into this kind of equipment, the housing (100) has at least one resiliently deflectable detent member (142, 152), which, for its actuation, is associated with a respective actuation member (144, 154) that is operable from the front side of the housing. Troughs (160, 170) are located on the front side (102), and a respective actuator (146, 148, 156, 158) for each deflectable member is located in each. The detent member (142, 152) has pretensioning which urges the detent member away from the housing (100) so that, when the housing is slid into a piece of equipment, latching of the housing (100) therein is accomplished.

Abstract: A method for plugging a turbine wheel hole in a turbine wheel. The method may include the steps of: 1) obtaining a turbine wheel hole plug that includes an approximate cylindrical body, a first flange at a first end of the body, and a hollow cylinder at the second end of the body, wherein the body, the first flange and the hollow cylinder are sized such that: a) the cylindrical body fits snuggly into the turbine wheel hole; b) the first flange comprises a diameter that is greater than the diameter of the turbine wheel hole; and c) the hollow cylinder protrudes from one end of the turbine wheel hole when the turbine wheel hole plug is inserted into the other end of the turbine wheel hole until the first flange abuts the turbine wheel; 2) positioning the turbine wheel hole plug into the turbine wheel hole; and 3) deforming the hollow cylinder so that the hollow cylinder flares outward.

Abstract: An axial fan includes a motor section, an impeller, a housing, and a plurality of supporting ribs. The motor section and the impeller are disposed on the inside of the housing. In a connecting region between an inner end portion of the supporting rib and the base section, a first corner portion and a second corner portion are formed on the side of a rotational direction of the impeller and on the side opposite to the rotational direction, respectively. A curvature radius of the first corner portion is larger than a curvature radius of the second corner portion.