Abstract: A gas turbine having a rotor which includes a turbine rotor, a shaft and a compressor rotor, the turbine rotor having at least one rotor disk and a rotor cone leading from the or a rotor disk to the shaft, the downstream end of the shaft being rotatably supported in a bearing having a bearing chamber, the interior space of the shaft being designed as a flow channel for bearing-chamber sealing air, and the space surrounding the rotor cone upstream of the same being designed as a flow space for cooling air is disclosed. In the region of the rotor connection, the shaft exhibits an expanded portion, at whose upstream end, openings are provided to allow cooling air to enter, and, at whose downstream end, openings are provided to allow cooling air to exit into the space between the bearing chamber and the rotor cone, a wall separating the streams of the cooling air and of the sealing air in the shaft interior from one another.

Abstract: A rotor assembly having a first component and a second component. The second component is secured within a bore of the first component by a first adhesive and a second adhesive. The first adhesive forms an annular seal between the first component and the second component, and the second adhesive extends from the first adhesive and has a lower viscosity than that of the first adhesive.

Abstract: A rotor assembly having a shaft, a bearing assembly, an impeller and a shroud. The impeller and the bearing assembly are mounted to the shaft, and the shroud is mounted to the bearing assembly so as to cover the impeller.

Abstract: Controllable pitch blade non-ducted propeller for a jet engine, comprising a rotor member comprising radial housing for mounting blade support plates, each plate being attached in a ring centered and guided in rotation in a housing of the rotor member and comprising external toothing engaged and locked in internal toothing of the ring, to withstand the centrifugal forces to which the propeller blades are subjected in operation.

Abstract: There is provided a vertical axis wind turbine comprising an upright rotatable shaft mountable on a support structure, a plurality of upright blades, and a plurality of prestressable supporting arms for attaching the plurality of blades to the shaft. The wind turbine may further comprise a shaft stabilizing assembly comprising a plurality of coplanar wheels having compliant outer layers, rotatably mounted on a support, for radially and rotatably supporting a rotatable shaft. The disclosure further provides a method of assembly of the wind turbine.

Abstract: This invention embodies a description of a “flat-disk radial flow turbine engine”, the “Internal Combustion Boundary Layer Turbine Engine” (BLTE), which is scalable in size and can provide high, medium or low power outputs respectively. The BLTE provides these outputs at much higher efficiency than that of a reciprocating engine or a conventional radial flow turbine engine. This engine offers simple and inexpensive construction with commonly available machine tools. This engine offers the light weight and high power output capability of a continuous burn turbine engine with reduced exhaust flow and reduced emissions. The BLTE application of differentially sized flat blades solves the problem of internal combustion and multi-stage operation for this new category of engine.

Abstract: An apparatus and method for maintaining separation of two journal foil bearing assemblies, where each journal foil bearing assembly comprises one or more foils with lugs formed thereon for insertion into axial grooves of a bore, the means comprising a pin for insertion into each groove so that an edge of the lug that is inserted into the groove abuts the pin and is prevented from axially drifting along the bore. The pin provides a broad area along the lug edge so that the lug edge does not cut into the pin.

Abstract: A gas turbine engine comprises a hollow rotor including a plurality of rotor segments stacked and coupled together in a direction of its center axis and forming at least one of a compressor and a turbine; and a pipe unit inserted into an inner space of the rotor in the center axis direction. In the gas turbine engine, a weight distribution of the pipe unit within an axial transverse section is set eccentric with respect to the center axis of the rotor. In this way, a gas turbine engine which is high in performance and reliability is provided, in which a pipe provided in an inner space of the rotor to transport a cooling medium or lay out a cable, etc., is prevented from whirling.

Abstract: A method for servicing a gas turbine engine includes providing access from a forward section of the gas turbine engine to a gearbox contained within a bearing compartment. A gas turbine is also disclosed in which a bearing package is mounted to a front center body support and a low spool. A front wall is removable from the front center body support to provide access to the gearbox.

Abstract: In a disc turbine for operation from steam, including superheated steam, a stack of horizontally oriented discs is fitted centrally with a hub having a closed upper end from which a driveshaft extends upwardly, supported by a bearing system. The hub is configured with identical vanes arrayed uniformly about the central axis and specially shaped to accomplish a set of desired flow path objectives. The vanes are generally tapered such that their cross-sectional shape evolves from predominantly solid material in area at the top of the hub to predominantly open area at the bottom of the hub, where the flow paths proceed downwardly into a tubular exhaust passageway. The entry to the exhaust passageway may take the form of effectively a hollow portion of the shaft in the exhaust region, which may be supported from the enclosure by a bearing set. The central opening in each disk, and thus in the stack, and in the periphery of the hub are both configured with a complementary mating interface pattern: e.g.

Abstract: A double row tapered bearing assembly includes a first portion and a second portion. The first portion includes a first ring and a second ring. The first ring is connected with the second portion via at least one row of tapered rollers or balls. The second ring is also connected with the second portion via at least one row of tapered rollers or balls. The first ring and the second ring each includes at least one groove. The at least one groove in the first ring faces the at least one groove in the second ring to form a cavity. At least one member is placed in the cavity.

Abstract: A fan with pressurizing structure includes a rotor having a main body, blades spaced on the main body, a magnetic body annularly mounted in the main body, and a shaft axially connected to an inner side of the main body; a frame having a sleeve and at least one bearing rotatably received in the sleeve, and an opposing end of the shaft being inserted into the bearing; a stator assembly fitted around the sleeve and including silicon steel plates and a base plate; and a plurality of first pressurizing sections selectively provided on one of the base plate and an end face of the magnetic body. With the first pressurizing sections, deposition of moisture and salt fog in the sleeve and the rotor can be prevented to avoid corroded and damaged bearing and rotor shaft, and the service life of the whole fan is increased.

Abstract: A wind turbine includes at least one turbine blade coupled to a rotor and configured to rotate about a central axis, a gearbox having an input configured to receive rotational input from the rotor, and an output configured to direct rotational output to a generator, a flow passageway configured to receive a lubrication fluid and direct the lubrication fluid to at least one component within the gearbox and a primary variable orifice device positioned along the flow passageway and configured to selectively vary an area of an orifice within the passageway in dependence upon at least one of a temperature or a viscosity of the lubrication fluid.

Abstract: A rotor hub has a yoke with radial arms allowing flapping of connected blades about a flap axis. A grip is rigidly attached to each blade, and a lead-lag bearing connects each grip to one of the arms, the bearing defining a lead-lag axis outboard of the flap axis. Each arm has a pair of straps located on opposite sides of the rotor plane for transferring centrifugal force from the blades to the central portion of the yoke. A pair of lead-lag dampers is provided for each grip, the dampers of each pair being located on opposite sides of the rotor plane and connecting an inboard end portion of the grip to the adjacent strap. In-plane motion of a blade causes rotation of the attached grip about the lead-lag axis, causing opposite motion of an inboard end portion of the grip. The dampers act to oppose rotation of the grip.

Abstract: A spindle is provided, comprising a spindle body having a first end, a second end, and a channel extending from the first end to the second end; a first end cover and a second end cover, the first and second end covers being releasably securable to the first and second ends, respectively, for defining a sealed space within the channel; the channel being configured for receiving at least one ball bearing assembly, a shaft, and a fluid; such that the at least one ball bearing assembly, a portion of the shaft, and the fluid are contained within the sealed space when the first and second end covers are secured to the first and second ends.

Abstract: A locking nut assembly including a bearing nut having a plurality of external serrations, a shaft nut having a plurality of external serrations, and a locking collar having a plurality of internal serrations. The bearing nut and the shaft nut are threadedly installed on a shaft assembly having an impeller, a bearing, and a spline adapter installed within the impeller. The plurality of serrations of the bearing nut align with the plurality of serrations of the shaft nut when they are installed on the impeller. The locking collar is installed on the bearing nut and the shaft nut so that the aligned plurality of serrations of the bearing nut and the plurality of serrations of the shaft nut engage the plurality of serrations of the locking collar. The locking collar is retained on the bearing nut and shaft nut by a retaining ring.

Abstract: It is intended to improve maintainability of a seal structure in a place where the rotation shaft is inserted in the housing. A seal structure of a mechanical device is provided with a housing 18 having an opening in which an input shaft 21 is inserted, a holding plate 41 which is connected to a periphery of the opening of the housing 18 and which has an opening in which the input shaft 21 is inserted, a felt ring 46 which is provided in the holding plate 41 and which seals a space between the holding plate 41 and the input shaft 21, a separable housing 43 which is provided to cover the holding plate 41 and a separable oil seal 45 which seals the space between the holding plate 41 and the input shaft 21 and a space between the cover and the rotation shaft.

Abstract: A tapered roller bearing comprises an outer ring (32), an inner ring (33), a plurality of tapered rollers (34) arranged between the outer ring (32) and the inner ring (33), and a plurality of retainer segments (11a) having pockets for holding the tapered rollers (34) and arranged so as to be continuously lined with each other in a circumferential direction between the outer ring (32) and the inner ring (33). Here, the tapered roller (34) is arranged between two adjacent retainer segments (11b) and (11c) except for between the first retainer segment (11a) and the last retainer segment lined continuously with each other in the circumferential direction.

Abstract: A turbine engine blade outer air seal segment has a body having a base portion. The base portion has a transversely concave ID face, a forward end, an aft end, and first and second circumferential edges. The body has at least one mounting hook. The body comprises a metallic member and a ceramic member. The ceramic member and metallic member are joined along the base portion with the ceramic member inboard of the metallic member.

Abstract: A wind turbine is provided with a rotor, a substantially horizontal rotor shaft, with a machine frame, with output means for dissipating the rotation energy of the rotor; wherein the output means are formed as ring gear or planet carrier of a gear box; the rotor shaft is connected in a rotation-fixed manner to the machine frame; the rotor has a hub and at least one rotor blade attachable thereto, is rotatably supported on the rotor shaft, and is connected substantially in a rotation-fixed manner to the output means; wherein decoupling connecting means are effectively arranged between the output means and the rotor, so as to substantially prevent the transmitting of radial, axial and/or tilting motions from the rotor onto the output means.

Abstract: A pump includes a cutting impeller (38) and a pre-chopper (50) driven by a shaft portion (46) that projects axially from the cutting impeller (38), with the pre-chopper (50) being surrounded by an intake port (22) of the pump, the intake port having, at least on a part of its length, in the vicinity of the pre-chopper, a non-circular internal cross-section.

Abstract: A rotor decoupler system for a gas turbine engine is disclosed, comprising a load reduction system disposed between a bearing system and the bearing support. The load reduction system comprises a fuse and a damper such that the damper transfers at least a part of the radial load from the rotor to the bearing support when a fuse fails. In one exemplary embodiment the damper comprises a wire mesh, disposed around the outer race of the bearing. In another exemplary embodiment the damper comprises a rope damper assembly. In yet another exemplary embodiment, a load reduction system is disposed between a support structure and a frame, comprising an extensional fuse and a damper disposed between the support structure and the frame such that the damper transfers at least a part of the unbalance load to the frame when an extensional fuse fails.

Abstract: A propeller assembly includes a rotatable hub having a center metal hub portion and an outer composite hub portion. A set of composite propeller blades are mounted for pitch control rotation on the hub by a set of dry bearings.

Abstract: A cooling fan includes a fan housing (30) having a central tube (34) extending upwardly therefrom, a bearing (60) being received in the central tube, a stator (20) being mounted around the central tube, and a rotor (10) having a shaft (18) extending through the bearing. At least one notch (180, 184) is defined in an end of the shaft. A balance structure (62) is mounted around the shaft, and has a portion facing and surrounding an upper portion of the at least one notch of the shaft. The balance structure is made of magnetic material, which can attract the shaft downward to thereby counter the upward force generated by the rotor when it is driven to rotate. Accordingly, the noise problem incurred by the floating of the rotating rotor can be resolved by the present invention.

Abstract: There is provided a wind turbine generator that includes an improved grease supply and discharge system of lubricant oil used in a blade rotating ring bearing of a wind turbine blade, and can reliably recover discharged grease. The wind turbine generator includes a pitch control mechanism that can adjust a pitch angle of the wind turbine blade via the blade rotating ring bearing provided between the wind turbine blade and a rotor head, a grease supply and discharge device is provided in the rotor head, and the grease supply and discharge device includes a grease supply device that pumps lubricant oil in a supplied grease tank with a grease supply pump and supplies the lubricant oil to the blade rotating ring bearing, and a grease discharge device that forcibly sucks and recovers the discharged grease from the blade rotating ring bearing.

Abstract: A drive train for a wind turbine, comprising a main bearing arrangement in the form of a single locating bearing arranged to support a main shaft. An outer raceway of the main bearing is coupled to a support structure, such as a base frame of a nacelle, via flange parts arranged on the outer raceway and the support structure, respectively. The flange parts define interfacing surfaces extending in a plane which is arranged non-parallel, preferably substantially perpendicular, to the rotational axis of the main shaft. Thereby a service friendly design is obtained, in which the main bearing and/or the main shaft can be repaired and/or replaced without having to remove the rotor from the nacelle.

Abstract: A turbocharger thrust bearing assembly, which maintains a constant relationship between the thrust faces, for example by use of gimbal or spherical segment geometry. Spherical geometry, while more difficult to manufacture than that of a flat thrust bearing, provides a more constant relationship between the thrust pads and thrust washers than is possible with a typical flat thrust bearing. As a consequence of this more constant relationship the thrust bearing operates with less oil flow, which ultimately may reduce vehicle emissions.

Abstract: A lubrication system and wind turbine are provided having one or more input ports in a component and one or more output ports in the component. An expandable lubrication receptacle is connected to the one or more output ports, and the expandable lubrication receptacle is configured for receiving a lubrication medium from the component.

Abstract: The present invention provides a fan including a stator and a rotor coupled to the stator. The stator has a base and a bearing disposed inside the base. The rotor has a shaft supported by the bearing. Furthermore, the shaft has a concave structure formed on a surface thereof, or the bearing has a groove structure formed on a surface thereof.

Abstract: Disclosed is a method for heat-treating a ring-shaped member, which makes it possible to form a quench-hardened region having a uniform annular shape in the circumferential direction, while the production costs in terms of the quenching apparatus are kept down. The method includes the following steps: a step in which a coil which is disposed in such a way as to face a rolling contact surface of a ring-shaped formed body made of steel and which performs induction heating of the formed body is rotated relative to the formed body in the circumferential direction thereof, whereby an annular heating region which is heated to a temperature at or above an A1 point is formed on the formed body; and a step in which the whole of the heating region is simultaneously cooled to a temperature at or below an MS point.

Abstract: A wind energy plant with a rotor, which is coupled to a gear via a rotor shaft, the rotor shaft being double bearing mounted via one rotor side bearing and one gear side bearing, wherein a connection between the rotor shaft and gear is provided at the gear side of the gear side bearing, and the gear side bearing props up on a machine carrier via at least one supporting equipment and the gear is detachably connected with the supporting equipment.

Abstract: The invention relates to a switchable coolant pump for combustion engines which is driven by a pulley, wherein the impeller can be driven switchably by the pulley by way of a friction pairing. It is the aim of the invention to develop a switchable coolant pump for combustion engines of the above type, which is simple to manufacture in terms of the manufacturing engineering thereof, driven by a pulley, and which is suited particularly for smaller coolant pumps (which is to say, coolant pumps in which the distance between the pulley and the impeller is smaller than 15 mm and the pulley diameter of which is smaller than 50 mm).

Abstract: A compressor rotor seal includes a bare radial inward end of a rotor vane in proximity to a rotor surface coated with an abrasive material.

Abstract: A wind turbine main bearing realized to bear a shaft of a wind turbine, which shaft is caused to rotate by a number of blades connected to the shaft is disclosed. The wind turbine main bearing includes a fluid bearing with a plurality of bearing pads arranged about the shaft. Also disclosed is a wind turbine with a number of blades connected to a shaft and realized to rotate the shaft, which wind turbine includes as main bearing a wind turbine main bearing. Further described is a method of performing maintenance on a wind turbine, including the steps of halting a rotation of the shaft, operating a lifting arrangement to raise the shaft, and removing a bearing pad of the wind turbine main bearing from the bearing housing of the wind turbine main bearing.

Abstract: A turbine engine component includes a shaft and two sets of hollow radial plates. The shaft includes an axial section forming a portion of a main passage having a substantially uniform diameter. The axial section has two ends and a center located substantially halfway between the two ends. The first set of hollow radial plates extends radially outwardly from the shaft at a first axial location between the center and a first end of the axial section. Each hollow radial plate is hollow and has an interior surface defining annular chambers surrounding and in flow communication with the main passage. The second set of hollow radial plates extends radially outwardly from the shaft at a second axial location between the center and a second end of the axial section. Each hollow radial plate has an interior surface defining annular chambers surrounding and in flow communication with the main passage.

Abstract: A three row roller bearing, in particular for a wind turbine, is provided. The three row roller bearing includes a row of radial rollers receiving radial load and a pair of rows of axial rollers receiving axial load. The axial rollers are tapered. A wind turbine using the three row roller bearing is also provided.

Abstract: An oil-sealing arrangement for cooling fan includes a fan housing provided with a central hollow pipe having a hollow bearing fitted therein in a clearance fit relation, and the bearing having a front end formed into a forward tapered projection; and a blade carrier including a fitting cylinder with a rearward tapered projection. When the fitting cylinder is extended into the hollow pipe on the fan housing, the rearward tapered projection and the forward tapered projection together define a seeped oil chamber between them. When the cooling fan operates, lubricating oil seeped out of the hollow pipe along the bearing is recovered in the seeped oil chamber and flows back to the hollow pipe via the clearance between the bearing and the hollow pipe without being centrifugally thrown out of the cooling fan, allowing the cooling fan to have extended usable life.

Abstract: A fan includes a plurality of blades and a motor. The motor includes a hub and a shaft having an end connected to the hub, a bushing, a bearing, and an oil-sealing structure. The blades are connected with and surrounding around the hub. The bushing is for supporting the other end of the shaft, and the bearing is disposed in the bushing and used to telescope the shaft. The shaft passes through the oil-sealing structure. The oil-sealing structure is telescoped to the shaft to fit tightly and the oil-sealing structure includes a main body and a barricade inwardly extending toward the shaft so that the oil-sealing structure is fixedly connected with the bushing.

Abstract: A method of operating a wind turbine having a bearing assembly, a shaft received therein, and at least one sub-system capable of altering a dynamic state of the wind turbine includes monitoring at least one parameter indicative of a load on the shaft; comparing the at least one parameter to a threshold criteria; and when the at least one parameter meets the threshold criteria, altering the dynamic state of the wind turbine to reduce the load on the shaft; and/or altering the state of the bearing assembly to better accommodate the load on the shaft. A control system for the wind turbine includes a controller operatively coupled to the bearing assembly and the at least one sub-system, and at least one sensor for monitoring at least one parameter indicative of a load on the shaft. The controller signals the sub-system or the bearing assembly when the threshold criteria is met.

Abstract: A support for a bearing that guides a shaft in a turbomachine is disclosed. The support includes an annular part made of a shape memory material which retains an initial shape when the load applied to it remains below a threshold value and which deforms, absorbing energy when the applied load becomes at least equal to the threshold value. The annular part is capable of reverting at least approximately to its initial shape when the applied load drops back below the threshold value.

Abstract: A coupling structure for connecting an impeller to a motor shaft of a liquid pump, includes a carrier rod sleeved on the shaft, and a seal assembly connecting the carrier rod to a housing of the pump. The carrier rod is fixed to the shaft by way of a screw thread structure. The seal assembly includes a rotating seal sealingly fixed on an outer surface of the carrier rod and fixed to the carrier rod for rotation there with by an interlocking structure.

Abstract: To provide a bearing support structure and a gas turbine that prevent damage of device induced by a rotor shaft when the rotor shaft is unbalanced, the bearing support structure and the gas turbine includes: a casing (7) formed in a cylindrical shape; a bearing unit (8) formed in a cylindrical shape and housed in the casing (7); a rotation shaft (5) rotatably supported by the bearing unit (8); and a reaction-force decreasing unit (13) that connects the casing and the bearing unit, and is configured to decrease a radial reaction force on the bearing unit side.

Abstract: A rotor hub (10) of a wind power plant for a rotor, in particular with at least one rotor blade is provided, wherein a hub core body (12) and at least one hub outer body (16) are connected together by means of a flange connection (18). The rotor hub (10) is further characterized in that the flange connection (18) is constructed with a predetermined tilt angle (?) towards the rotational axis (24) of the rotor, wherein the tilt angle (?) of the flange connection (18) is constructed larger than the tilt angle (?) of the rotor blade connection surface of the hub outer body (16). Furthermore, a wind power plant may be provided with the rotor hub (10).

Abstract: A fan includes an impeller and a motor for driving the impeller to rotate. The motor includes a bushing and a rotating shaft penetrating through the bushing. The bushing includes a tube and at least one base connected with one end of the tube. An inner diameter of the tube is smaller than an inner diameter of the base so that the mechanism design variability is enhanced and the efficiency of the fan and the motor is enhanced by effectively utilizing an inner space of the bushing.

Abstract: The present invention provides a water lubricated line shaft bearing assembly, comprising an outer annular steel shell and an inner layer made of low friction material attached to the outer shell, the inner layer having a non-uniform thickness which is formed with wall portions of increased thickness defining a plurality of shaft engaging portions and with wall portions of reduced thickness defining a plurality of lubricant passages. The shaft engaging portions are capable of being journalled on a line shaft adapted to drive a downhole geothermal production pump and the steel shell is engageable with an inner wall of a lubrication tube vertically extending through a water column through which pumped geothermal fluid is delivered, lubrication water bled from the pumped geothermal fluid being used to supply lubrication water through the lubricant passages.

Abstract: Durable pumps for abrasives are provided. In one implementation, an example centrifugal pump or pump stage for subsurface operation has a thrust washer located inside the circumference of a close-fitting clearance seal between an impeller shroud and the diffuser. The relocation of the thrust washer allows the clearance seal to protect the thrust washer from abrasives while the thrust washer supports the impeller against the reaction forces of axial fluid flow. In one implementation, the radius or size of a thrust washer or other seal-like feature is reduced in order to increase exposure of the bottom impeller shroud to pressured fluid, thus balancing pressure at the top and bottom of the impeller to decrease friction between the impeller and the thrust washer. Reducing the radius of the thrust washer also reduces surface area of the washer subject to friction and reduces the moment arm of a braking torque on the rotating impeller, thereby reducing power loss in the pump.

Abstract: On a two-shaft engine for an aircraft gas-turbine with a central low-pressure shaft, with a high-pressure shaft co-axially surrounding the low-pressure shaft and with bearing units supporting the shafts on the engine casing, the bearing loads of the high-pressure shaft are directed upstream towards the fan and the bearing loads of the low-pressure shaft are directed downstream. In order to reduce axial bearing load of the high-pressure bearing unit, the oppositely directed bearing loads of the low-pressure shaft (3) and of the high-pressure shaft (6) partly compensate one another, in that the front thrust bearing unit (10) of the high-pressure shaft (6) is supported on the engine casing (1) and the front thrust bearing unit (12) of the low-pressure shaft (3) is supported on the high-pressure shaft (6).

Abstract: Hydrogen gas compression systems that each include a multistage centrifugal compressor in which each stage has an inlet-to-outlet pressure rise ratio of about 1.20 or greater. In one embodiment, the multistage compressor includes six high-speed centrifugal compressors driven at a speed of about 60,000 rpm. The compressor has an output of more than 200,000 kg/day at a pressure of more than 1,000 psig. The compressors for the compression stages are distributed on both sides of a common gear-box, which has gearing that allows axial thrusts from the compressors to be handled effectively. Each stage's compressor has a unique impeller, which is secured to a support shaft using a tension-rod-based attachment system. In another embodiment, the multistage compressor is driven by a combustion turbine and one or more intercoolers are provided between compression stages. Each intercooler is cooled by coolant from an absorption chiller utilizing exhaust gas from the combustion turbine.

Abstract: The invention relates to a turbocharger (15) comprising a bearing housing (7) which mounts a rotor shaft (12) and has a bearing-housing oil space (13); comprising a compressor housing which is connected to the bearing housing (7) and has a compressor space (14); and comprising a sealing device (20) which is provided for sealing the bearing-housing oil space (13) relative to the compressor space (14) and which has a sealing ring (1) which is arranged in a fixed position in the bearing housing (7) and has two end faces (17, 17?) which interact with associated end faces (10) and (11) of a disc (9) and a sealing bush (16) which are fastened to the rotor shaft (12), wherein the sealing ring (1) is arranged with axial play on the rotor shaft (12) between the disc (9) and the sealing bush (16); and air-delivery devices (2, 3) oriented in opposition are arranged in the end faces (17, 17?) of the sealing ring (1).

Abstract: A cooling fan includes a fan housing (10) having a shaft seat (16) extending downwardly therefrom, a stator (20) being fixedly mounted around the shaft seat, a shaft (80) with a top end being fixedly connected to the shaft seat and a free end (82) extending downwardly therefrom, a rotor (30) comprising a hub (32) having a plurality of blades (34) extending radially and outwardly, and a sleeve bearing (40). A fixing tube (36) extends upwardly from a center of the hub. The fixing tube has a closed bottom end and defines a fixing hole (360) therein. The sleeve bearing is fixedly received in the fixing hole of the fixing tube to rotate with the rotor. A bearing hole is defined in the sleeve bearing for extension of the free end of the shaft therethrough.