JP2020096530A - Electric blower and vacuum cleaner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric blower capable of high-speed rotation and suppression of efficiency decrease, and an electric vacuum cleaner provided with the electric blower. SOLUTION: The outer periphery of the rotor core is provided with one cover provided so as to cover from one end side to the other end side in the axial direction of the rotor core, and a stator and a housing are configured on the outer periphery of the cover. The housing is provided with an opening for guiding the wind generated in the blower portion to the rotor core and the stator, the rotor core is composed of a magnet, and the cover is an austenitic stainless steel containing 12% or more of nickel. The cooling air passes between the cover and the stator. [Selection diagram] Fig. 3

Description

The present invention relates to an electric blower and an electric vacuum cleaner equipped with the electric blower.

2. Description of the Related Art As a conventional electric blower for an electric vacuum cleaner, a brushless motor has been proposed for downsizing, and a structure corresponding to high-speed rotation has been proposed. For example, in a rotor assembly that constitutes an electric blower described in Patent Document 1, a rotor core (magnet) is attached to one end of a shaft, an impeller is attached to the other end of the shaft, and a rotor core of the shaft and an impeller are provided. A bearing is attached between the two.

Special table 2012-518751 gazette

However, in the invention described in Patent Document 1, the strength due to the centrifugal force applied to the rotor core must be taken into consideration, and there is a problem that the magnet that can be used as the rotor core and the manufacturing method are limited.

For example, rare earth magnets such as samarium-cobalt magnets and samarium-iron-nitrogen magnets have small toughness and may be broken by centrifugal force. Further, as a manufacturing method, when insert molding of the rotor core onto the shaft is performed, internal stress may be generated due to the difference in shrinkage ratio during cooling, which may cause cracking.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an electric blower that can be rotated at high speed without being affected by the type of magnet and the manufacturing method, and an electric vacuum cleaner including the electric blower. .. Furthermore, it aims at providing the electric blower which suppresses the fall of efficiency, and the electric vacuum cleaner provided with the same.

According to the present invention, a blower unit is configured by a rotary shaft that is rotatably provided, a centrifugal impeller provided at one end of the rotary shaft, and a diffuser having a diameter larger than that of the centrifugal impeller. A cylindrical rotor core provided in, the centrifugal impeller, at least one bearing arranged between the rotor core, and an outer periphery of the rotor core from one end side to the other end side in the axial direction of the rotor core. A cover is provided so as to cover the outer periphery of the cover with a stator and a housing, and the housing is provided with an opening for guiding the wind generated in the blower unit to the rotor core and the stator. In addition, the rotor core is made of a magnet, the cover is made of austenitic stainless steel containing 12% or more of nickel, and the cooling air passes between the cover and the stator. ..

ADVANTAGE OF THE INVENTION According to this invention, the electric blower which can be rotated at high speed, and can suppress the fall of the efficiency of an electric blower by suppressing the magnetic flux fall by temperature rise by cooling a rotor effectively, and this. An electric vacuum cleaner provided with can be provided.

The electric vacuum cleaner which mounts the electric blower in this embodiment is shown, (a) is a perspective view at the time of using it as a stick type, (b) is a side view at the time of using an electric vacuum cleaner as a handy type. It is a longitudinal cross-sectional view of the cleaner body in which the electric blower according to the present embodiment is mounted. It is an exploded perspective view showing the electric blower in this embodiment. It is an exploded perspective view showing a rotor assembly of an electric blower. It is a side view which shows the electric blower in this embodiment. It is a longitudinal section showing the electric blower in this embodiment. It is a perspective view which shows a centrifugal impeller. The external view of the shroud board which comprises a centrifugal impeller is shown, (a) is a perspective view, (b) is a side view, (c) is a rear view. It is a perspective view which shows the state which removed the shroud of the centrifugal impeller. It is a longitudinal cross-sectional view of a centrifugal impeller. It is a perspective view when the rotor assembly is seen from the ring member side. It is a schematic diagram which shows the relationship between the blade of a centrifugal impeller, and a rotor core. (A) is a perspective view of a guide vane, (b) is a rear view of the guide vane, (c) is a longitudinal sectional view of the guide vane. It is explanatory drawing which shows the flow of the air in a diffuser. (A) is a perspective view of a fan casing, (b) is a longitudinal cross-sectional view of a fan casing. FIG. 3A is a perspective view in which a housing and a bearing cover are integrated, and FIG. 3B is a rear view in which a housing and a bearing cover are integrated. It is sectional drawing in the AA line of the electric blower of FIG. 16A is a sectional view taken along the line BB of FIG. 16A, and FIG. 16B is a sectional view taken along the line C-C of FIG. 16A. It is a perspective view of a bearing cover. FIG. 11P is a simplified view of FIG. 11P when the cover is made of a magnetic material. FIG. 11B is a simplified view of FIG. 11P when the cover is made of a non-magnetic material. It is the relationship between magnetic permeability and materials. It is the relationship between the amount of nickel and the magnetic permeability.

Hereinafter, modes for carrying out the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the drawings as appropriate. In addition, below, although the case where it applies to a rechargeable vacuum cleaner 400 that can be used by appropriately switching between a stick type and a handy type will be described as an example, but various types such as only a stick type and a handy type can be used. It can be applied to vacuum cleaners.

FIG. 1 shows an electric vacuum cleaner equipped with an electric blower according to the present embodiment, (a) is a perspective view when used as a stick type, and (b) is a side view when the electric vacuum cleaner is used as a handy type. is there.

As shown in FIG. 1A, an electric vacuum cleaner 400 is a vacuum cleaner that houses a dust collection chamber 401 for collecting dust and an electric blower 200 (FIG. 2) that generates a suction airflow necessary for collecting the dust. Main body 410, telescopic pipe 402 that is provided to be able to extend and contract with respect to the main body 410 of the vacuum cleaner, grip portion 403 that is rotatably provided at one end of the telescopic pipe 402, and turning on/off of electric blower 200 provided on the grip portion 403. The switch unit 404a and the switch unit 404b (see FIG. 1B) for performing the above are configured.

The electric vacuum cleaner 400 shown in FIG. 1A is in a stick state, in which the telescopic pipe 402 is extended and the grip portion 403 is rotated and locked on the side opposite to the telescopic pipe 402 and locked. Further, a suction body 405 is attached to the other end of the cleaner body 410, and the cleaner body 410 and the suction body 405 are connected by a connecting portion 406.

The electric vacuum cleaner 400 shown in FIG. 1B is in a handy state, in which the telescopic pipe 402 is housed in the cleaner body 410, and the grip portion 403 is rotated to the telescopic pipe 402 side. Further, the rotated grip portion 403 is clamped by a clamp member 407 provided on the upper surface of the cleaner body 410. Further, a suction body (gap nozzle) 408 is attached to the other end of the cleaner body 410, and the cleaner body 410 and the suction body 408 are connected by a connecting portion 406.

In the above electric vacuum cleaner 400, by operating the switch portion 404a (see FIG. 1A) or the switch portion 404b (see FIG. 1B) of the grip portion 403, the electric power stored in the cleaner body 410 is changed. The blower 200 (see FIG. 2) operates to generate a suction air flow. Then, dust is sucked from the suction ports 405 and 408, and is collected in the dust collecting chamber 401 of the cleaner body 410 through the connecting portion 406.

FIG. 2 is a vertical cross-sectional view of a cleaner body equipped with the electric blower according to this embodiment. 2 is a handy state, in which the suction body 408 (see FIG. 1B) is removed from the cleaner body 410.

As shown in FIG. 2, inside the cleaner body 410, an electric blower 200 that generates a suction force, a battery unit 420 that supplies electric power to the electric blower 200, and a drive circuit 430 are provided.

The air sucked from the suction ports 405 and 408 (see FIGS. 1A and 1B) passes through the flow path 440 (see FIG. 1A) provided in the cleaner body 410, and the air of the electric blower 200 is removed. It is sent to the dust collection chamber 401 arranged in the front and collected in the dust collection chamber 401. Then, the air from which dust has been separated in the dust collection chamber 401 passes through the electric blower 200 and the drive circuit 430, and is discharged to the outside from an exhaust port (not shown) formed in the cleaner body 410.

FIG. 3 is an exploded perspective view showing the electric blower according to this embodiment.

As shown in FIG. 3, the electric blower 200 is a DC brushless motor and includes a fan casing 204, guide vanes 205, a housing 208, fixing screws 218 and 219, a rotor assembly 230, a stator 240, and the like.

An air inlet 206 is formed in the fan casing 204. The guide vane 205 includes a plurality of diffuser vanes 13, a diffuser 205a having a substantially triangular flow path 18, and a return guide 205b having a plurality of return guide vanes 14 on the back surface of the diffuser 205a. Further, the guide vanes 205 are fixed to the housing 208 via fixing screws 218.

The stator 240 is fixed to the housing 208 via fixing screws 219. The rotor assembly 230 is inserted through the guide vanes 205 and the housing 208, and the rotor core 209 provided in the rotor assembly 230 is arranged at a position facing the stator 240.

FIG. 4 is an exploded perspective view showing a rotor assembly of the electric blower.

As shown in FIG. 4, the rotor assembly 230 includes a centrifugal impeller 203, a rotating shaft 207, a rotor core 209, bearings 212 and 212, a ring member 213, a spring 217, and a cover 250. The bearings 212, 212 and the spring 217 form a bearing portion.

The centrifugal impeller 203 is made of a thermoplastic resin and is fixed to one end (tip) of the rotating shaft 207. The rotating shaft 207 has an elongated cylindrical shape and is made of a magnetic material such as iron. In the present embodiment, the centrifugal impeller 203 is press-fitted and fixed to the rotary shaft 207, but a screw may be provided at the end (tip) of the rotary shaft 207 and the centrifugal impeller 203 may be fixed by a fixing nut.

Further, bearings 212, 212 are provided at substantially the center of the rotating shaft 207 in the axial direction G (direction in which the rotating shaft 207 extends) so as to be separated from each other in the axial direction G (see FIG. 3 ). The centrifugal impeller 203 is fixed to one end of the rotating shaft 207, and the ring member 213 is fixed to the other end of the rotating shaft 207.

The cover 250 is formed by forming a non-magnetic thin plate into a tubular shape, and in this embodiment, an austenitic stainless alloy having no magnetism is used (see FIG. 22). Further, when plastic deformation is usually performed by working such as deep drawing, austenite transforms to martensite and has magnetism. Therefore, in this example, an alloy containing nickel in a proportion of 12% or more is used in order to stabilize austenite and suppress transformation during processing (see FIG. 23). Further, when a material having a nickel content of 12% or less is used, it is returned to austenite from martensite by heat treatment by heating to 900° C. or higher after processing.

Further, the cover 250 has a flange portion 250a bent inward in the radial direction at one axial end of the cover 250 itself. When the cover 250 is inserted from one end side of the rotating shaft 207, the flange portion 250a comes into contact with the end surface 209a of the rotor core 209 and is hooked to be positioned. As described above, by covering the rotor core 209 with the cover 250, it is possible to prevent the rotor core 209 from being broken and scattered when the rotor core 209 is rotated at a high speed.

By the way, when the cover 250 is magnetized, the magnetic flux of the rotor core 209 returns to the rotor core 209 through the cover 250, so that the force acting on the rotor core 209 is weakened and the efficiency of the electric blower 200 is reduced (FIG. 20). reference). Therefore, by forming the cover 250 with a non-magnetic material, the magnetic flux of the rotor core 209 can be transmitted to the stator core 210 through the cover 250, and the efficiency of the electric blower 200 can be prevented from decreasing (see FIG. 21). ..

A spring 217 is provided on the rotating shaft 207 between the bearing 212 and the bearing 212. The bearing 212 includes, for example, an outer ring 212a, an inner ring 212b, and a plurality of balls 212c. The outer ring 212a is fixed to the housing 208 and the inner ring 212b is fixed to the rotating shaft 207. The spring 217 is composed of a coil spring, and urges the outer rings 212a of the bearings 212, 212 in directions away from each other. As a result, rattling of the bearing 212 is prevented, so that the sound and vibration of the electric blower 200 are suppressed.

FIG. 5 is a side view showing the electric blower in this embodiment.

As shown in FIG. 5, the electric blower 200 is roughly divided into a blower unit 201 and an electric motor unit 202. The blower unit 201 includes a centrifugal impeller 203 (see FIG. 3 ), a fan casing 204 that houses the centrifugal impeller 203, and guide vanes 205 (see FIG. 3 ).

The electric motor unit 202 is configured to include a rotor core 209 (see FIG. 4) fixed to the rotating shaft 207 (see FIG. 3) housed in the housing 208, and a stator core 210 fixed to the housing 208.

FIG. 6 is a vertical cross-sectional view of the electric blower according to this embodiment.

As shown in FIG. 6, in the stator 240, a conductor wire 211 is wound around a stator core 210, and the conductor wire 211 forms a phase winding together. The phase winding is electrically connected to a circuit unit (not shown) included in the electric blower 200.

The rotor core 209 is provided at the end of the rotating shaft 207 opposite to the end where the centrifugal impeller 203 is fixed. The rotor core 209 is composed of, for example, a rare earth-based bond magnet. The rare earth-based bonded magnet is made by mixing rare earth magnetic powder and an organic binder. As the rare earth-based bond magnet, for example, a samarium iron-nitrogen magnet, a neodymium magnet, or the like can be used. The rotor core 209 is formed integrally with the rotary shaft 207.

As described above, by configuring the rotor core 209 with the bond magnet, the electric blower 200 can be reduced in weight. Further, by using the bond magnet, the weight of the ring member 213 can be reduced, and the weight of the electric blower 200 can be reduced.

In this embodiment, a permanent magnet is used for the rotor core 209, but the present invention is not limited to this, and it is a kind of non-commutator motor capable of high-speed rotation of, for example, 80,000 rpm or more. A reluctance motor or the like may be used.

Bearings 212, 212 are provided on the rotating shaft 207 between the centrifugal impeller 203 and the rotor core 209. The bearings 212, 212 are arranged apart from each other in the axial direction, and rotatably support the rotating shaft 207.

The ring member 213 is for balance adjustment, and is provided at the end of the rotating shaft 207 on the rotor core 209 side (the other end of the rotating shaft 207). The ring member 213 is made of a non-magnetic material that has a larger specific gravity than the rotor core 209. The ring member 213 can be formed by, for example, a sintered product (sintered body) such as a copper material or a machine process.

As described above, by forming the ring member 213 with a non-magnetic material such as copper, the magnetic circuit that acts when the rotor assembly 230 is rotated (the magnetic circuit that operates between the rotor core 209 and the stator core 210) is adversely affected. It is possible to prevent giving. Further, by using a sintered product of copper material, the dimensional accuracy can be increased and the manufacturing cost can be reduced.

Further, the ring member 213 is not limited to copper as long as it is a non-magnetic material having a larger specific gravity than the rotor core 209, and stainless alloy, gold, silver, lead, or the like can be used.

Further, the rotating shaft 207 is provided with a positioning sleeve 214 for the bearing 212 between the rotor core 209 side bearing 212 and the rotor core 209.

The housing 208 is made of synthetic resin and has a support portion 26 for fixing the bearing cover 215 that encloses the bearings 212, 212. Bearings 212, 212, a sleeve 216, and a spring 217 are provided in the bearing cover 215. The spring 217 is arranged in a compressed state and abuts the outer rings of the bearings 212, 212 to apply a preload.

A plurality of cooling fins 27, which are heat sinks for cooling the bearing 212 and are long in the rotation axis direction, are provided on the outer periphery of the bearing cover 215. Further, the bearing cover 215 is made of a non-magnetic metal material and is integrated with the resin housing 208 by insert molding.

Further, a screw hole 28 extending in the axial direction G is formed in the support portion 26 of the housing 208. A fixing screw 218 can be screwed into the screw hole 28, and the guide blade 205 is fixed to the housing 208 by screwing the fixing screw 218.

Further, the housing 208 is formed with an opening 34 through which air flows into the housing 208 and an exhaust port 35 for discharging air to the outside of the electric blower 200. The stator core 210 arranged at the end of the housing 208 in the axial direction G is fixed to the housing 208 with a fixing screw 219.

The magnetic center L1 of the rotor core 209 is arranged in a state shifted in the axial direction G with respect to the magnetic center L2 of the stator core 210. The magnetic center L1 is the center of the rotor core 209 in the axial direction G, and the magnetic center L2 is the center of the stator core 210 in the axial direction G. As a result, a force (force in the thrust direction) that pulls the rotor core 209 toward the stator core 210 acts, thereby preventing rattling in the axial direction G of the rotor during high-speed rotation, and noise and vibration can be reduced. When the centrifugal impeller 203 rotates at high speed, the rotor assembly 230 generates a force that pulls the rotor assembly 230 toward the centrifugal impeller 203. Since this force and the force generated by shifting the magnetic center are in opposite directions, the mechanical loss during high-speed rotation is reduced and high efficiency can be achieved. Further, at the time of assembly, when the rotor assembly 230 is inserted into the bearing cover 215, a force directed to the stator core 210 side is generated, so that workability can be improved.

7 is a perspective view of the centrifugal impeller, FIG. 8 is an external view of a shroud plate constituting the centrifugal impeller, (a) is a perspective view, (b) is a side view, (c) is a rear view, and FIG. Is a perspective view showing a state in which the shroud plate is removed from the centrifugal impeller, FIG. 10 is a longitudinal sectional view of the centrifugal impeller, and FIG. 11 is a perspective view of the rotor assembly as seen from the ring member side.
Is.

As shown in FIG. 7, the centrifugal impeller 203 includes a shroud plate 1, a hub plate 2, and a plurality of blades 3. The hub plate 2 and the blades 3 are integrally formed of thermoplastic resin.

As shown in FIG. 8A, the shroud plate 1 has a ring-shaped suction opening 4 formed in the center thereof for sucking air. The suction opening 4 is formed with a straight line portion 5 extending substantially parallel to the rotary shaft 207 (see FIG. 6). The tip 5a of the linear portion 5 is formed so that the plate thickness (in the radial direction) is thinner than the base end (see FIG. 10).

As shown in FIG. 8B, the shroud plate 1 is formed with a curved surface portion 6 that diverts the axial flow flowing from the suction opening 4 into a radial flow.

As shown in FIG. 8( c ), the shroud plate 1 is configured such that the straight line portion 5 and the curved surface portion 6 are smoothly connected and that the curved surface portion 6 faces the outer diameter in the radial direction. Further, on the back surface of the shroud plate 1, a concave groove 7 is formed at a position corresponding to the blade 3 from the curved surface portion 6 toward the outer diameter. The concave groove 7 extends from the inner diameter end to the outer shape end of the shroud plate 1. Further, the concave groove 7 is formed with a through hole 8 that fits with a claw 10 (see FIG. 9) formed on each blade 3.

As shown in FIG. 9, a convex boss 9 into which the rotary shaft 207 (see FIG. 4) is inserted and fixed is formed in the center of the hub plate 2. The blades 3 integrally formed with the hub plate 2 are installed at equal intervals in the circumferential direction, and have a blade shape that recedes in the rotational direction from the radially inner side toward the radially outer side. The boss 9 has a curved surface 9a formed radially outward from the shaft side.

A protruding claw 10 is formed on the upper surface of the blade 3, and a welding rib 11 is formed on the outer diameter side of the claw 10. Further, on the upper surface of the blade 3, an inclined surface 12 is formed on the pressure surface (convex surface) side of the blade 3 so as to be in close contact with the curved surface portion 6 of the shroud plate 1 from the claw 10 to the inner diameter side. The shape (cross-sectional shape) of the rib 11 for welding may be triangular, semicircular, or trapezoidal.

While inserting the claw 10 of the blade 3 into the through hole 8 (see FIG. 8A) of the shroud plate 1, the concave groove 7 (see FIG. 8C) of the shroud plate 1 and the blade 3 are engaged, The centrifugal impeller 203 is formed by joining the claw 10 and the rib 11 to the shroud plate by welding.

The curved surface portion 6 of the shroud plate 1 and the inclined surface 12 of the blade 3 are not welded.
Thereby, the welding can be simplified because the welding can be performed only from the axial direction from the curved surface portion 6 of the shroud plate 1 to the outer diameter. Further, the rib 11 melts in the concave groove 7, but the volume of the rib 11 is made smaller than the volume of the gap when the blade 3 is inserted into the concave groove 7. Therefore, it is possible to suppress the molten resin material from protruding into the flow path of the centrifugal impeller 203.

Further, in the centrifugal impeller 203, the welding ribs 11 of the blades 3 are melted and welded to the shroud plate 1 in the flow passage where the pressure increases from the vicinity of the center of the flow passage to the outlet, so that the space between the blades 3 is welded. Leakage can be prevented.

Further, an inclined surface 12 is formed on the front edge side of the centrifugal impeller 203, which is closer to the front edge side than the claw 10 of the blade 3, so as to match the shape of the curved surface portion 6 of the shroud plate 1. Further, in the centrifugal impeller 203, the inlet flow is particularly important, and since the curved surface portion 6 of the shroud plate 1 is not welded, burrs due to welding do not occur on the inclined surface 12 of the blade 3. .. That is, the air can be smoothly flowed into the blade 3 without disturbing the flow on the inlet side.

Further, as shown in FIG. 10, in the centrifugal impeller 203, the suction opening 4 (see FIG. 8A) is formed in the shroud plate 1, and the straight line portion 5 and the curved surface portion 6 are formed to be smooth surfaces. At the same time, a curved surface 9a (see FIG. 9) is formed so that the boss 9 on the flow path surface of the hub plate 2 extends from the axial direction G in the radial direction. Therefore, the flow of the air in the axial direction G that has flowed in from the suction opening 4 can be made to flow into the blades 3 while being smoothly turned to the radial direction, and the bending loss at the inlet of the centrifugal impeller 203 can be reduced. ..

Further, when the centrifugal impeller 203 is operated, the curved surface portion 6 of the shroud plate 1 and the inclined surface 12 of the blade 3 work closely due to centrifugal force on the leading edge side, so that the blade 3 and the shroud plate 1 are connected on the inlet side. The gap is eliminated, and the efficiency of the electric motor section 202 (electric blower 200) can be improved.

Further, although the centrifugal impeller 203 is made of a thermoplastic resin, in order to prevent deformation due to heat generated from the electric blower 200 and the like, heat resistance is 100° C. or higher, and tensile strength is high to withstand centrifugal stress. It is desirable to use an engineering plastic material having 100 MPa or more. For example, polyether ether ketone (PEEK) or PEEK containing carbon fiber is more preferable. This makes it possible to realize a resin centrifugal impeller 203 that is lighter in weight than the metallic centrifugal impeller, secures strength, and can withstand high-speed rotation.

When the electric motor unit 202 is driven to rotate the centrifugal impeller 203, air flows in from the air suction port 206 of the fan casing 204 and flows into the centrifugal impeller 203. The inflowing air is pressurized and accelerated in the centrifugal impeller 203 and is discharged from the centrifugal impeller 203. The airflow discharged from the centrifugal impeller 203 is guided to the guide vanes 205.

As shown in FIG. 11, in the centrifugal impeller 203, a convex portion 2a is formed along the circumferential direction on the outer circumference of the back surface side of the blade 3 of the hub plate 2 (see FIG. 10). In other words, the outer peripheral edge portion 203a of the centrifugal impeller 203 is formed to be thicker in the axial direction G than on the inner peripheral side. Balance adjustment is performed on each manufactured rotor assembly 230. At this time, the convex portion 2a of the hub plate 2 and the end surface 213a of the balance adjusting ring member 213 attached to the shaft end of the rotating shaft 207 are adjusted. , Are removed from the axial direction G (see holes P1 and P2) to correct the balance.

In this way, by cutting the outer peripheral edge portion 203a (outer peripheral side) of the centrifugal impeller 203, it is possible to correct the balance with a smaller amount of scraping than the inner peripheral side. Further, by forming the ring member 213 with a material having a larger specific gravity than the rotor core 209, the shape of the ring member 213 can be made smaller than that formed with resin, and the electric blower 200 can be downsized. Therefore, by providing the ring member 213 at the end of the rotating shaft 207, it is possible to suppress the amount of unbalance during rotation of the rotating body (rotor assembly 230), and to reduce vibration and noise. The efficiency of the electric blower 200 can be improved. Further, since the balance can be adjusted at both ends of the rotary shaft 207 (the ring member 213 and the centrifugal impeller 203), the balance adjustment becomes easy. In this way, the amount of unbalance of the rotating body (rotor assembly 230) including the centrifugal impeller 203 can be reduced, vibration and noise can be reduced, and high-speed rotation of 80,000 rpm or more is possible. The electric blower 200 can be realized.

FIG. 12 is a schematic diagram showing the relationship between the blades of the centrifugal impeller and the rotor core. Note that FIG. 12 shows a state where the shroud plate 1 of the rotor assembly 230 is removed, and the central portion of the centrifugal impeller 203 is simplified.

As shown in FIG. 12, in the rotor assembly 230, the number of blades 3 of the centrifugal impeller 203 is eight, and the number of poles of the rotor core 209 is two, N and S. Thus, the number of blades 3 is n (n is an integer) times the number of poles of the rotor core 209. With this configuration, the pole position and the blade position are rotationally symmetric for each pole regardless of the position of the rotor core pole position and the radial position of the centrifugal impeller blade position. The force generated by the rotor core 209 is evenly applied to the blades 3 of the centrifugal impeller 203 to reduce noise and vibration. The number of blades 3 is not limited to this embodiment as long as the number of blades 3 is n times the number of poles of rotor core 209, and can be changed as appropriate.

The weld 209b at the boundary between the north pole and the south pole of the rotor core 209 is configured to pass through the axis center O of the rotation shaft 207. This makes it possible to reduce the amount of unbalance of the magnetic flux densities of the N pole and the S pole in the rotor core 209, reduce noise and vibration, and improve the efficiency of the electric blower 200.

Next, the guide vanes 205 of the present embodiment will be described with reference to FIGS. 13 and 14. 13A is a perspective view of the guide vane, FIG. 13B is a rear view of the guide vane, FIG. 13C is a longitudinal sectional view of the guide vane, and FIG. 14 is an explanatory diagram showing a flow in the diffuser.

As shown in FIG. 13A, the guide vanes 205 are made of resin, and have a plurality of diffuser vanes 13, a plurality of return guide vanes 14 formed on the downstream side of the diffuser vanes 13, and a diffuser vane. A partition plate 15 for partitioning the space 13 and the return guide vane 14 is integrally formed.

A rib 13a is formed on the upper surface of the diffuser blade 13, and the rib 13a is in contact with the inner surface 25a (see FIG. 6) of the fan casing 204 (see FIG. 6). On the diffuser 205a side, the fan casing 204, the diffuser blades 13, and the partition plate 15 form a diffuser flow path R1 (see FIG. 6).

A through hole 16 a for inserting the rotor assembly 230 is formed in the center of the partition plate 15. Further, in the partition plate 15, through holes 16b are formed at a plurality of locations around the through hole 16a. The guide blade 205 is fixed to the housing 208 by inserting a fixing screw 218 (see FIG. 3) into the through hole 16b and screwing the fixing screw 218 into the screw hole 28 of the housing 208.

As shown in FIG. 13B, on the return guide 205b side, the partition plate 15 and the return guide vanes 14 form a return guide flow path R2 (see FIG. 6). Further, a cylindrical convex portion 17 is formed on the outer periphery of the through hole 16b on the return guide 205b side. The convex portion 17 and the concave portion 29 (see FIG. 3) of the housing 208 are fitted to each other to prevent leakage to the blower unit 201 (see FIG. 6) side.

As shown in FIG. 13C, the outer diameter side of the diffuser blade 13 is gently inclined in the axial direction to form a diffuser flow path R3 inclined in the axial direction (downward in the drawing).

As shown in FIG. 14, the guide vanes 205 allow the air flowing out from the gap between the diffuser vanes 13 and the diffuser vanes 13 to the outer peripheral end side of the diffuser vanes 13 to flow toward the return guide vanes 14 (see FIG. 13B). A substantially triangular flow path (communication path) 18 is formed. The inflow flow 19 to the diffuser vane 13 is decelerated in the diffuser flow path R1 (see FIG. 3) surrounded by the diffuser vane 13, the partition plate 15 and the fan casing 204 which are adjacent to each other, and hits the inner surface 204b of the fan casing 204. , And becomes an outflow 20 which is turned in the axial direction G through the flow path 18 having a substantially triangular shape. The outflow 20 has a flow component in the swirling direction, and the return guide vanes 14 (see FIG. 13B) turn the swirling flow into a radially inward flow.

The diffuser 205a of the guide vane 205 includes a plurality of diffuser vanes 13, and the air flow is decelerated between the vanes of the diffuser vanes 13, whereby the kinetic energy of the air flow is converted into pressure energy and the pressure rises. The airflow discharged from the diffuser 205a flows into the return guide 205b from the flow path 18 (see FIG. 14) formed between the inner surface of the fan casing 204 and the rear edge of the diffuser 205a. Although the diffuser with blades is used in the present embodiment, a diffuser without blades may be used. In that case, a plurality of columns are provided on the outer diameter side of the guide blade to support the fan casing 204.

The air that has passed through the return guide vanes 14 of the return guide 205b flows into the housing 208 through the openings 34 of the housing 208, cools the cooling fins 27 of the bearing cover 215, and cools the bearing 212 via the bearing cover 215. (See Figure 6). Further, the air cools the rotor core 209, the stator core 210, and the conductor wire 211 and is discharged to the outside.
As a result, each part inside the housing 208 is cooled. A part of the airflow that has passed through the return guide vanes 14 is discharged to the outside from the exhaust port 35 of the housing 208.

The return guide vane 14 is provided so as to be located in the opening 34 (see FIG. 6) of the housing 208. The flow turned radially inward by the return guide vanes 14 hits the cooling fins 27 of the bearing cover 215 through the openings 34 of the housing 208, and the bearing 212 is effectively cooled. This makes it possible to realize the electric blower 200 with the bearing 212 having high reliability.

Since the diffuser flow path R1 (see FIG. 6) formed by the fan casing 204, the diffuser blades 13, and the partition plate 15 is gently inclined (see FIG. 13(c)), it has a substantially triangular shape in plan view. The flow passage 18 (see FIG. 14) can smoothly flow to the return guide blade 14, and bending loss can be reduced. Thereby, the efficiency of the electric motor section 202 can be improved. Further, since sufficient airtightness can be obtained by the cylindrical convex portion 17 (see FIG. 13C) of the return guide 205b and the concave portion 29 (see FIG. 3) of the housing 208, the efficiency of the electric motor portion 202 can be further improved. You can

15A is a perspective view of the fan casing, and FIG. 15B is a vertical sectional view of the fan casing.

As shown in FIG. 15A, the fan casing 204 has a substantially umbrella shape that covers the centrifugal impeller 203 (see FIG. 3) and the guide vanes 205 (see FIG. 3) from the outside, and has a circular shape in plan view. A plate 21 and an annular side plate 22 that extends continuously in the axial direction in the peripheral portion of the upper plate 21 are provided.

On the side plate 22 of the fan casing 204, a plurality of protrusions 23 are formed on the edge portion on the side opposite to the upper plate 21 side. The protrusions 23 are formed at intervals in the circumferential direction. Further, the protrusion 23 is formed with a fixing hole 24 for fixing the fan casing 204 to the housing 208. In this embodiment, three protrusions 23 are formed, but the number is not limited to three, and four or more protrusions may be provided.

As shown in FIG. 15B, the fan casing 204 has an air suction port 206 formed in the center of the upper plate 21. A concave portion 204a is formed on the inner surface of the edge portion of the air suction port 206, and the linear portion 5 of the centrifugal impeller 203 is arranged in the concave portion 204a (see FIG. 6). The centrifugal impeller 203 is arranged so as to have a small gap between the fan casing 204 and the tip of the straight portion 5, and the amount of air leaked to the suction opening 4 side of the centrifugal impeller 203 by the air pressurized by the centrifugal impeller 203 is reduced. It has a structure. As a result, the sealing effect can be enhanced, and the efficiency of the electric motor section 202 can be further improved.

An airtight holding member 25 using an elastic body is arranged on the inner surface of the upper plate 21 of the fan casing 204. The airtight holding member 25 is made of an elastic material such as rubber or elastomer and is integrally formed with the fan casing 204. In this embodiment, the airtight holding member (elastic member) 25 and the fan casing 204 are integrally formed by insert molding. Further, the gate direction is set to the opposite side (outside) to the surface on which the centrifugal impeller 203 is arranged so that no gate mark is left inside. The ribs 13a (see FIG. 13A) provided on the diffuser blade 13 bite into the airtight holding member 25, so that the airtightness between the fan casing 204 and the guide blades 205 is maintained. This can prevent leakage between the guide vanes 205 between the diffuser blades 13 and improve the efficiency of the electric blower 200.

16A is a perspective view in which the housing and the bearing cover are integrated, FIG. 16B is a rear view in which the housing and the bearing cover are integrated, and FIG. 17 is a cross-sectional view taken along the line AA of the electric blower in FIG. 18A is a sectional view taken along line BB in FIG. 16A, FIG. 18B is a sectional view taken along line CC in FIG. 16A, and FIG. 19 is a perspective view of the bearing cover. ..

As shown in FIG. 16A, the housing 208 is made of synthetic resin and has a support portion 26 for fixing the bearing cover 215 that encloses the bearings 212, 212 (see FIG. 6). The support portion 26 has a substantially double-cylindrical shape, and is located inside the front portion (the upper portion in the drawing) of the housing 208.

As shown in FIG. 16B, a bearing cover 215 made of a non-magnetic metal material is fixed to the substantially cylindrical portion 26a inside the support portion 26. A plurality of cooling fins 27, which are heat sinks for cooling the bearing 212, are provided on the outer peripheral side of the bearing cover 215. The cooling fins 27 are long in the rotation axis direction, and are integrally formed with the support portion 26 of the housing 208. Since the bearing cover 215 has a complicated shape in which the cooling fins 27 are provided on the outer periphery, the bearing cover 215 can be manufactured by die casting to reduce the production cost and obtain high dimensional accuracy. As a material used for the bearing cover 215 and the cooling fin 27, an aluminum alloy which is a non-magnetic metal and has a high thermal conductivity is desirable.

In this embodiment, the housing 208 is formed by insert molding using the bearing cover 215 as an insert product. A screw hole 28 (see FIG. 16A) extending in the rotation axis direction is formed at the end of the support portion 26 of the resin housing 208. A fixing screw 218 can be screwed into the screw hole 28, and the guide blade 205 is fixedly installed in the housing 208 by screwing the fixing screw 218.

An annular recess 29 is provided on the outer diameter side of the screw hole 28. By fitting the concave portion 29 and the cylindrical convex portion 17 (see FIG. 13B) on the return guide 205b side, it is possible to prevent air leakage from the electric motor portion 202 side to the blower portion 201 side.

The outer peripheral portion of the support portion 26 is connected to a substantially cylindrical frame 31 by a bridge 30 (see FIG. 16A). A screw hole 32 for fixing the stator core 210 (see FIG. 6) is provided at the end of the frame 31 where the bridge 30 is located. A fixing screw 219 can be screwed into the screw hole 32, and the stator core 210 is fixed to the housing 208 by screwing the fixing screw 219.

Further, a claw-shaped protrusion 33 is provided at the end of the frame 31 on the side of the blower unit 201, and is fitted and connected to the fixing hole 24 of the fan casing 204. It is possible to secure the positioning accuracy of the fan casing 204 in the axial direction by the connection by fitting instead of the connection by the adhesive, and thus the airtightness between the fan casing 204 and the guide vanes 205 can be secured. Further, it is possible to reduce the variation in the tip clearance between the concave portion 204a of the fan casing 204 (see FIG. 6) and the linear portion 5 of the centrifugal impeller 203 (see FIG. 6), and improve the performance of the electric blower 200. Therefore, it is possible to reduce the performance variation.

In the housing 208, the openings 34 (see FIG. 16A) formed between the bridges 30 so that the air flows into the housing 208, and the rotor core 209, the stator core 210, and the conductive wire 211 are directly cooled to the outside without cooling. Exhaust ports 35 (see FIG. 16B) for discharging the are formed at a plurality of locations.

Inside the frame 31, inclined portions 36 (see FIG. 16A) are provided at a plurality of locations. Air that has flowed out from the flow path 18 (see FIG. 14) having a substantially triangular shape of the guide vanes 205 easily flows into the opening 34 by the return guide vane 14 (see FIG. 13B) and the inclined portion 36. ing. The air that has flowed in through the openings 34 hits a plurality of cooling fins 27 that are heat sinks provided in the bearing cover 215 and that are long in the rotation axis direction, and flow. The cooling fin 27 has a rectangular plate shape. The heat generated in the bearing 212 is transferred by heat conduction through the bearing cover 215 made of a non-magnetic metal material and is radiated by the cooling fins 27, so that the bearing 212 is effectively cooled.

By the way, in the motor unit 202, the mechanical loss generated in the bearing 212 is larger than the ratio of the copper loss generated in the conductor wire 211 wound around the stator core 210, and it is important to effectively cool the bearing 212. .. Even if the housing 208 is made of resin, the heat generated in the bearing 212 is radiated by the heat sink (cooling fin 27) provided in the bearing cover 215, so that the bearing 212 can be effectively cooled, and highly reliable electric drive is possible. The blower 200 can be provided.

Further, since the housing 208 is made of resin, the weight of the housing 208 and the weight of the electric blower 200 can be reduced. In the present embodiment, the bearing cover 215 and the resin housing 208 are integrated by insert molding, but the bearing cover 215 may be press-fitted into the resin housing 208.

As shown in FIG. 17, in the bearing cover 215, the cooling fin 27 is arranged at the position of the opening 34 of the housing 208, but the cooling fin 27 is not arranged in the bridge 30 of the housing 208. The bridge 30 is provided with ribs 26c (see FIG. 16B) instead of the cooling fins 27. The rib 26c connects the substantially double-cylindrical cylindrical portions 26a and 26b of the housing 208 to the bridge 30 and has the effect of increasing the rigidity of the housing 208.

The air having the swirling flow component flowing out from the flow path 18 having a substantially triangular shape (see FIG. 14) is diverted by the return guide vanes 14 into the swirling flow inward in the radial direction, and the cooling fins of the heat sink. Since it directly hits 27, a sufficient cooling effect can be obtained. As a result, a sufficient cooling effect can be obtained without providing the cooling fins 27 on the bridge 30, and the number of cooling fins can be reduced as compared with the case where the number of cooling fins is evenly provided in the circumferential direction, and a sufficient heat dissipation effect is achieved. The effect of weight reduction can also be achieved.

As shown in FIGS. 18A and 18B, the housing 208 and the bearing cover 215 are integrated by insert molding. The support portion 26 of the housing 208 has a substantially double cylindrical shape, and the axial length of the substantially cylindrical portion 26a on the inner diameter side is substantially the same as the axial length of the cooling fin 27, but the outer diameter The axial length of the substantially cylindrical portion 26b on the side is approximately half the axial length of the cooling fin 27.

As described above, since the bearing cover 215 is provided with the cooling fins 27, the bearing fins 215 have high rigidity, and the cooling fins 27 are included by the substantially cylindrical portion 26a on the inner side and the substantially cylindrical portion 26b on the outer side of the substantially double-cylindrical support portion 26. In such a manner that the cooling fin 27 extends over the inner cylindrical portion 26a and the outer cylindrical portion 26b, the housing 208 is integrally formed. Therefore, the rigidity of the bearing cover 215 and the housing 208 can be increased, and high-speed rotation of 80,000 rpm or more can be achieved.

In the present embodiment, the substantially cylindrical portion 26b on the outer diameter side is approximately half the length of the cooling fin 27, but when the rigidity of the housing 208 is sufficiently high, the outer diameter side 26b is used to enhance the cooling effect. The length of the substantially cylindrical portion 26b may be shortened, and the length of the portion of the cooling fin 27 that is exposed to the cooling air may be increased.

As shown in FIG. 19, a cylindrical reference surface 37 without the cooling fins 27 is provided at the end of the bearing cover 215 in the axial direction. The reference surface 37 is a reference surface when insert-molding the bearing cover 215 and the resin housing 208, and is a reference when cutting the inner diameter for fixing the outer ring 212a (see FIG. 4) of the bearing 212 (see FIG. 6). .. By forming the reference surface 37 into a cylindrical shape, it is possible to easily form the reference surface when the inner diameter is cut by a lathe or the like. Moreover, it is possible to reduce the number of parts to be machined by a lathe. As a result, the dimensional accuracy is improved, the central axes of the stator core 210 attached to the housing 208 and the rotor core 209 attached to the rotating shaft 207 are aligned with each other, and the efficiency of the electric motor section 202 is improved, and vibration and noise are further improved. It is possible to obtain the electric blower 200 that can reduce the noise.

Although the reference surface 37 has a cylindrical shape in the present embodiment, the reference surface 37 is not limited to this, and may have a polyhedral shape as long as it can be used as a reference for cutting the inner diameter and a reference for insert-molding the housing 208. Any shape may be used.

Here, the rotor core 209 is assembled into the housing 208 after being magnetized, but since the bearing cover 215 is made of a non-magnetic metal, it is not affected by the attraction force of the magnet and is excellent in assembling property. ..

Further, in the present embodiment, a plurality of cooling fins 27 that are long in the rotation axis direction are provided as a heat sink, and the cooling fins 27 have a rectangular plate shape, but a pin shape such as a large number of columnar shapes, conical shapes, or prismatic shapes. May be That is, any shape may be used as long as it has a shape projecting in the circumferential direction so that the cooling fins 27 extend over the substantially cylindrical portion 26a on the inner side and the cylindrical portion 26b on the outer side in order to radiate heat from the bearing. By forming the cooling fin 27 into a pin shape, the volume can be reduced to obtain the same surface area, and the mass can be reduced.

By mounting the electric blower 200 configured in this way on the electric vacuum cleaner 400, the output of the electric vacuum cleaner 400 can be improved. Further, since the efficiency of the electric motor unit 202 is improved, when the same output is obtained, the input of the electric blower 200 can be lowered, and the operating time of the rechargeable vacuum cleaner having the battery unit 420 as a drive source can be extended. You can

DESCRIPTION OF SYMBOLS 1 Shroud plate 2 Hub plate 2a Convex part 3 Blade 4 Suction opening 5 Straight part 6 Curved part 7 Recessed groove 8 Through hole 9 Boss 10 Protruding claw 11 Rib 12 Sloping surface 13 Diffuser blade 14 Return guide blade 15 Partition plate 16 Through Hole 17 Convex part 18 Flow path of substantially triangular shape 19 Inflow flow to diffuser blade 20 Outflow flow from diffuser blade 21 Upper plate 22 Side plate 23 Protrusion 24 Fixing hole 25 Airtight holding member 26 Support part 27 Cooling fin 28 Screw hole 29 Recess 30 bridge 31 frame 32 screw hole 33 claw-like protrusion 34 opening 35 exhaust port 36 inclined part 37 reference surface 200 electric blower 201 blower part 202 electric motor part 203 centrifugal impeller 203a outer peripheral edge 204 fan casing 205 guide vane 205a diffuser 205b return Guide 206 Suction port 207 Rotating shaft 208 Housing 209 Rotor core 210 Stator core 211 Conductor 212 Bearing 213 Ring member 214 Positioning sleeve 215 Bearing cover 216 Sleeve 217 Spring 218 Fixing screw 219 Fixing screw 230 Rotor assembly 240 Stator 250 cover 400 Vacuum cleaner 410 Vacuum cleaner body G axis direction R1 Diffuser flow path R2 Return guide flow path

Claims (7)

A rotation shaft that is rotatably provided,
A centrifugal fan impeller provided at one end of the rotating shaft, and a blower unit composed of a diffuser having a larger diameter than the centrifugal impeller,
A cylindrical rotor core provided on the rotating shaft,
The centrifugal impeller, and at least one bearing arranged between the rotor core,
On the outer circumference of the rotor core, one cover provided so as to cover from one end side to the other end side in the axial direction of the rotor core is provided.
A stator and a housing are formed on the outer periphery of the cover, and the housing is provided with an opening for guiding the wind generated in the blower unit to the rotor core and the stator.
The rotor core is made of a magnet, the cover is made of austenitic stainless steel containing 12% or more of nickel, and the cooling air passes between the cover and the stator. Electric blower for. A rotation shaft that is rotatably provided,
A centrifugal fan impeller provided at one end of the rotating shaft, and a blower unit composed of a diffuser having a larger diameter than the centrifugal impeller,
A cylindrical rotor core provided on the rotating shaft;
The centrifugal impeller, and at least one bearing arranged between the rotor core,
On the outer circumference of the rotor core, one cover provided so as to cover from one end side to the other end side in the axial direction of the rotor core is provided.
A stator and a housing are formed on the outer periphery of the cover, and the housing is provided with an opening for guiding the wind generated in the blower unit to the rotor core and the stator.
The rotor core is composed of a magnet, and the cover is composed of austenitic stainless steel containing less than 12% of nickel. After the shape is formed, heat treatment is performed, and the cooling air blows between the cover and the stator. An electric blower for an electric vacuum cleaner characterized by passing through. The electric blower for an electric vacuum cleaner according to claim 1 or 2, wherein the cover has a flange portion that extends radially inward at one axial end of the cover itself. Among the electric blowers according to any one of claims 1 to 3, the maximum rotation speed operates at 80,000 to 100,000 revolutions per minute, and the electric blower input is in the range of approximately 200W to 500W. An electric blower for an electric vacuum cleaner, characterized in that the rotor core has a diameter in the range of 5 mm to 15 mm. The electric motor for a vacuum cleaner according to any one of claims 1 to 4, wherein the cover is formed by deep drawing and has a flange portion that extends radially inward at one axial end of the cover itself. Blower. An electric vacuum cleaner comprising the electric blower according to any one of claims 1 to 5. A rotation shaft that is rotatably provided,
A centrifugal impeller provided at one end of the rotating shaft,
A cylindrical rotor core whose axial length is longer than the diameter provided on the rotating shaft;
The centrifugal impeller, and at least one bearing arranged between the rotor core,
On the outer circumference of the rotor core, one cover provided so as to cover from one end side to the other end side in the axial direction of the rotor core is provided.
The rotor core is composed of a magnet,
The cover is a method for manufacturing an electric blower for an electric vacuum cleaner, which is made of austenitic stainless steel containing less than 12% nickel.
A method for manufacturing an electric blower for an electric vacuum cleaner, characterized in that the cover is subjected to a process involving plastic deformation by deep drawing and then subjected to a heat treatment.

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