JP7428630B2 - Electric blower and vacuum cleaner equipped with it - Google Patents

Description

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

Conventionally, the following Patent Document 1 has been disclosed as an electric blower.
Patent Document 1 describes ``an impeller (10) that rotates around a central axis (C) that extends vertically, and a motor that has a stator (24) arranged below the impeller (10) and rotates the impeller (10). (20), a motor housing (21) that accommodates the stator (24), and a first flow path (5) that accommodates the impeller (10) and the motor housing (21) and is located in the gap between the motor housing (21) and the motor housing (21). The upper part of the fan casing (2) covers the upper part of the impeller (10) and has an intake port (103) that opens in the vertical direction. An exhaust port (104) that communicates with the intake port (103) via the first flow path (5) is provided at the lower part, and the motor housing (21) has a stator (21) fixed to the inner surface of the motor housing (21). 24) An inlet (21a) penetrating in the radial direction and communicating with the first flow path (5) is provided below the upper surface of the motor housing (21), and the motor housing (21) extends upward from the inlet (21a). "A blower device (1) having a second flow path (6) communicating with a space above the stator (24)."

JP2018-105269A

Incidentally, the operating air volume of a vacuum cleaner varies greatly depending on operating conditions such as clogging of the filter due to dust and the material of the floor to be cleaned. For this reason, vacuum cleaners are required to be electric blowers with strong suction power over a wide air volume range. In addition, electric blowers are required to be smaller and lighter in terms of ease of use of vacuum cleaners. As a result, the heat dissipation area is reduced, the heat generation density inside the electric blower is increased, and there is a need to improve the cooling performance of the electric motor and bearings.

In addition, although a diffuser with wings can perform excellent pressure recovery at the design point air volume, at non-design point air volume, the diffuser performance deteriorates due to the mismatch between the inlet angle of the diffuser blade and the inflow angle of the air flow into the diffuser. descend. Therefore, although the suction force of the vacuum cleaner is high at the design point air volume, there is a fear that it may decrease at non-design point air volume.

Cordless stick type or autonomous type vacuum cleaners that are powered by batteries (secondary batteries) consume less power and have a smaller maximum airflow due to the battery capacity. Therefore, there is a problem that when the filter becomes clogged, the dirt conveying ability is reduced and the suction power of the vacuum cleaner is reduced. Furthermore, vacuum cleaners powered by batteries (secondary batteries), such as cordless stick or self-driving types, are required to be small and lightweight, and electric blowers installed in vacuum cleaners have suction power over a wide range of air volume. It is required to be both strong and compact.

As mentioned above, Patent Document 1 discloses that ``a fan casing (2) that configures a first flow path (5) in a gap between an impeller (10) and a motor housing (21) that houses a motor (20). The upper part of the fan casing (2) covers the upper part of the impeller (10) and has an intake port (103) that opens in the vertical direction, and the lower part of the fan casing (2) has a first flow path (5). The motor housing (21) is provided with an exhaust port (104) that communicates with the intake port (103) through the motor housing (21). An inlet (21a) is provided which penetrates in the direction and communicates with the first flow path (5), and the motor housing (21) extends upward from the inlet (21a) to form a space above the stator (24). It has a second flow path (6) that is in communication with the second flow path (6).'' That is, in Patent Document 1, the flow in the first flow path (5) is branched by a structure, flows into the second flow path (6), and flows into the ball bearing of the fan side ball bearing located above the stator (24). (26), then cools the bearing (26) of the sliding bearing on the anti-fan side, and is shown to be exhausted to the outside of the electric motor (motor 20) without merging with the first flow path. .

In the blower (1) of Patent Document 1, the air volume of the first flow path (5) passes through the inflow port (21a) that penetrates in the radial direction and communicates with the first flow path (5), and the air volume flows through the second flow path (6). ), the air volume in the first flow path (5) downstream of the inlet (21a) communicating with the inlet (21a) decreases compared to the air volume upstream of the inlet (21a) due to pressure loss (resistance) in the flow path. .

Note that a diffuser with wings can perform excellent pressure recovery at the design point air volume, but if the air volume falls below the design point air volume, the diffuser Performance may decrease and the suction power of the vacuum cleaner may decrease. The second flow path (6), which extends upward from the inlet (21a) of the second flow path (6) and communicates with the space above the stator (24), has a small flow path area. Furthermore, since the flow curves inside the electric motor (20), the pressure loss in the flow path is large, the cooling air volume decreases, the temperature inside the electric motor (motor 20) increases, and there is a concern that the motor efficiency will decrease. .

The present invention was devised to solve the above-mentioned problems in view of the above-mentioned circumstances, and aims to provide a compact and lightweight electric blower that is highly efficient in a wide air volume range, and a vacuum cleaner equipped with the same.

In order to solve the above problems, an electric blower of the present invention includes an electric motor including a rotor having a rotor core, a stator having a stator core and having a coil wound thereon, and a motor housing housing the rotor and the stator. , an impeller disposed upstream of the motor housing, a first axial diffuser vane disposed downstream of the impeller, and a second axial diffuser disposed downstream of the first axial diffuser vane. an anti-impeller side housing having a wing, an inner wall, an outer wall, and the second axial diffuser wing formed between the inner wall and the outer wall, the first axial diffuser wing is fixed so as to be located upstream from the center of the motor housing, and is arranged to cover the motor housing from upstream to approximately the center position in the longitudinal direction of the motor housing, and the second axial flow diffuser blade is The motor housing is arranged to surround the housing from approximately the center to downstream in the longitudinal direction of the motor housing , and the motor housing has an upstream opening formed on the upstream side of the rotor core, and an upstream opening formed on the downstream side of the rotor core. a downstream opening formed in the second axial diffuser, the downstream edge of the inner wall being located upstream of the trailing edge of the second axial diffuser blade and the downstream opening; The axial position of the trailing edge of the blade is within the axial position of the downstream opening.

According to the present invention, it is possible to provide an electric blower that is highly efficient in a wide air volume range, is small and lightweight, and suppresses the amount of heat generated, and a vacuum cleaner equipped with the electric blower.

1 is an external view of an electric blower according to a first embodiment of the present invention. FIG. 1B is a vertical cross-sectional view of the electric blower shown in FIG. 1A. FIG. 2 is a perspective view of the impeller of the first embodiment. FIG. 2B is a cross-sectional view of the impeller shown in FIG. 2A. FIG. 3 is a front view of the first axial diffuser blade of the first embodiment, viewed from the impeller side. FIG. 3B is a cross-sectional view of the first axial diffuser vane shown in FIG. 3A. FIG. 3B is a partially cutaway view of the shroud of the first axial diffuser vane shown in FIG. 3A; FIG. 7 is a front view of the second axial diffuser blade of the first embodiment, viewed from the impeller side. FIG. 4B is a cross-sectional view of the second axial diffuser vane shown in FIG. 4A. FIG. 4B is a partially cutaway perspective view of the shroud of the second axial diffuser vane shown in FIG. 4A; FIG. 2 is an external view of the electric motor of the first embodiment. FIG. 5B is a vertical cross-sectional view of the electric motor shown in FIG. 5A. FIG. 7 is a vertical cross-sectional view of an electric blower according to a second embodiment of the present invention. 1 is a perspective view of a vacuum cleaner to which an electric blower according to a first embodiment of the present invention is applied. FIG. 8 is a sectional view taken in the I direction of the vacuum cleaner main body in the vacuum cleaner shown in FIG. 7 .

Embodiments of the present invention will be described in detail below with reference to the drawings as appropriate.
<<First embodiment>>
FIG. 7 is a perspective view of a vacuum cleaner 300 to which the electric blower 200 according to the first embodiment of the present invention is applied.
FIG. 8 is a cross-sectional view of the vacuum cleaner main body 100 in the vacuum cleaner 300 of the first embodiment taken in the I direction.
A vacuum cleaner 300 according to a first embodiment of the present invention will be described.

<Configuration of vacuum cleaner 300>
The vacuum cleaner 300 includes a vacuum cleaner main body 100, a holding section 102 to which the vacuum cleaner main body 100 is attached, a grip section 103 that is held by a user, and a suction body 105 that sucks dust.
The battery unit 108 (see FIG. 8) that is the driving source of the vacuum cleaner 300 is charged using the charging stand 107 (see FIG. 7). The battery unit 108 is housed in the vacuum cleaner main body 100.

The vacuum cleaner body 100 houses a dust collection chamber 101 that collects dust and an electric blower 200 (see FIG. 8) that generates a suction airflow necessary for collecting dust.
A grip portion 103 is provided at one end of the holding portion 102 . The grip section 103 is provided with a switch section 104 (see FIG. 7) that turns on/off the electric blower 200.
A mouthpiece 105 is attached to the other end of the holding part 102. The suction body 105 and the cleaner main body 100 that generates the suction airflow are connected through a connecting portion 106.

When using the vacuum cleaner 300, the user turns on the switch section 104 of the grip section 103. Then, the electric blower 200 housed in the vacuum cleaner main body 100 starts operating, and a suction airflow is generated in the suction body 105. Dust on the floor Y (see FIG. 7) is sucked in from the suction body 105 by the suction airflow. The sucked dust passes through the connection part 106 and is collected in the dust collection chamber 101 of the cleaner body 100.

<Vacuum cleaner body 100>
Next, the vacuum cleaner main body 100 will be explained.
As shown in FIG. 8, an electric blower 200, a battery unit 108, a driving circuit 109, and a dust collection chamber 101 are arranged inside the vacuum cleaner main body 100.
Battery unit 108 drives electric blower 200 . The electric blower 200 generates suction force at the mouthpiece 105 .
The vacuum cleaner main body 100 includes a main body grip part 110 and a suction opening 111.
The user can grip the main body grip part 110, remove the vacuum cleaner main body 100 from the holding part 102, and use it as a handy vacuum cleaner.

The main body switch section 112 shown in FIG. 7 is a switch that turns on/off the electric blower 200 when the vacuum cleaner main body 100 is used as a handy vacuum cleaner. The main body switch 112 can be turned on/off in place of the switch part 104 even when the vacuum cleaner main body 100 is attached to the holding part 102.
Note that the vacuum cleaner 300 shown in FIGS. 7 and 8 is a cordless vacuum cleaner in which the suction opening 111 (see FIG. 9) and the connection part 106 are removable; however, the vacuum cleaner 300 shown in FIGS. You can also use a vacuum cleaner. Alternatively, a stick-type cordless vacuum cleaner having an extension pipe or a hose between the dust collection part and the suction port may be used.

<Electric blower 200>
FIG. 1A is an external view of an electric blower 200 according to a first embodiment of the present invention, and FIG. 1B is a longitudinal cross-sectional view of the electric blower 200 shown in FIG. 1A. Note that FIG. 1B shows a case where an annular anti-vibration rubber 21 is applied to the electric blower 200.
Next, electric blower 200 will be explained. Note that in FIG. 1B, typical air flows are shown only on the left side of FIG. 1B by a solid line arrow α1 and a dotted line arrow α2.

The electric blower 200 is attached to the vacuum cleaner 300 shown in FIGS. 7 and 8 with the impeller 1 facing the lower suction body 105.
As shown in FIG. 1B, the electric blower 200 includes an electric motor section 202 inside a blower section 201 in the radial direction.
The blower section 201 is provided with an impeller 1 which is a rotary blade, a first axial diffuser blade 23 on the impeller side, and a second axial diffuser blade 24 from the upstream side of the suction air flow. An exhaust port 32 is provided downstream of the second axial diffuser blade 24 .

The impeller-side housing 2 having the axial flow diffuser blades 23 on the impeller 1 side (closer to the impeller 1) is attached to a threaded portion provided in the motor housing 6 on the impeller 1 side.
The housing 9 on the anti-impeller side, which has the second axial diffuser blade 24 disposed on the side opposite to the impeller 1 (the side far from the impeller 1), is located downstream of the housing 2 on the impeller side (exhaust port). 32 side).

The electric motor section 202 is located inside the housing 2 on the impeller side and the housing 9 on the anti-impeller side in the radial direction. The housing 2 on the impeller side is located so as to cover the motor housing 6, and the housing 9 on the anti-impeller side is located so as to cover a part of the motor housing 10 in the axial direction. The opening 20 provided in the radial direction of the outer periphery is partially exposed.

The motor housing 6 on the impeller side has the same shape as the motor housing 10 on the anti-impeller side, and has a plurality of openings in the radial direction on the outer periphery (opening 15 of the impeller housing and the housing 10 on the anti-impeller side). opening 20). Note that the motor housing 10 on the side opposite to the impeller has an opening in the axial direction. Further, the openings facing in the radial direction on the outer circumference of each motor housing have six openings in the circumferential direction, and the openings are uniformly arranged. Further, the opening 15 of the motor housing 6 on the impeller side and the opening 20 of the motor housing 10 on the anti-impeller side are installed so as to sandwich the stator core 8 in the axial direction. Moreover, the opening of each motor housing is arranged so as to overlap the coil end in the axial direction. Note that the number of openings in the radial direction of the motor housing and the number of blades of the diffuser blades 24 on the side opposite to the impeller have the greatest common divisor of three. That is, the same flow field can be introduced into the opening at three locations in the circumferential direction, making it possible to reduce the temperature distribution in the circumferential direction. Note that the greatest common divisor is greater than 1, preferably greater than or equal to 3, or equal to the number of openings.
The motor housing 6 on the impeller side holds the bearing 11 on the impeller 1 side in the axial direction of the electric motor section 202 . The motor housing 10 on the side opposite to the impeller supports the bearing 12 on the side opposite to the impeller in the axial direction of the electric motor section 202.
The second flow path 19 includes a radial opening 20 in the motor housing 10 on the side opposite to the impeller, an opening 15 in the motor housing 6 inside the electric motor and on the impeller side, and an outer periphery of the motor housing 10 on the impeller side. and the inner wall 2a (first axial flow diffuser) of the housing on the impeller side.
A first flow path 18 passing through the impeller 1 , the impeller-side axial diffuser blade 23 , and the second axial diffuser blade 24 is provided on the side of the electric blower 200 . The first flow path 18 is a flow path through which the airflow due to the suction force at the mouthpiece body 105 flows.

The first flow path 18 and the second flow path 19 merge at an axial end 9c of the inner wall 9a of the housing 9 on the side opposite to the impeller. Note that the axial end portion 9c is located at approximately half the axial dimension of the second axial diffuser blade 24. By merging the first flow path 18 and the second flow path 19 at the axial end 9c, a flow in the second flow path is generated by the venturi effect of the main flow of the second axial diffuser blade 24. The cooling air is taken into the motor through the opening 20 of the motor housing 10 on the side opposite to the impeller and the opening 34 in the axial direction. Thereby, it is possible to improve the cooling performance of the electric motor unit 202 and increase the efficiency of the electric blower 200 over a wide operating range.
The axial end portion 9c may be approximately half the axial dimension of the second axial diffuser blade 24 or more, and may extend to the trailing edge of the blade, in order to generate cooling air due to the Venturi effect. is preferably located closer to the impeller than the opening 20 in the axial direction.

The second flow path 19 is located radially inner than the first flow path. Further, the openings of the motor housing 10 are formed in the axial direction 34 and the radial direction 20. By making the opening large, the amount of air generated by the Vencheri effect can be increased, and the inside of the electric motor can be cooled more efficiently when passing through the second flow path 19.
In addition, by locating the opening 20 of the motor housing 10 radially inward from the inner wall 9a of the housing, it becomes easier to secure the flow passage area of the second flow passage 19, and the inside of the electric motor can be cooled more efficiently.

Note that a part of the winding comes out from the opening 34 and is electrically connected to the driving circuit 109 (see FIG. 8). Here, the configuration of the opening of the motor housing may be a square hole, a round hole, or a hole of another shape.

In the impeller 1 shown in FIG. 1B, a metal sleeve 13 is covered with a hub 26 made of thermoplastic resin. The impeller 1 is fixed by a fixing nut screwed into a female screw threaded at the end of the rotating shaft 5. In the first embodiment, the impeller 1, which is a rotary blade, is provided with a female thread at the end of the rotary shaft 5, and is fixed using a fixing nut, but it may also be fixed by press-fitting. . Further, although the impeller 1 shown in FIG. 1B is a mixed flow type impeller, it may be a centrifugal type or an axial flow type impeller.

<Electric motor 202>
Next, the configuration of the electric motor section 202 of the first embodiment will be explained.
FIG. 5A is a side view of the electric motor 202, and FIG. 5B is a longitudinal cross-sectional view. The electric motor section 202 is provided with a rotor core 7 and a stator core 8 disposed on the outer periphery of the rotor core 7.
The rotor core 7 is housed within two motor housings and fixed to the rotating shaft 5.
A coil (winding) 17 is wound around the winding frame portion of the stator core 8 . The coil 17 is electrically connected to a drive circuit 109 (see FIG. 8) included in the electric blower 200.

Note that although copper wire is used for the coil, a smaller and lighter electric blower can be provided by using an aluminum wire or a composite wire material using a copper material around the aluminum wire coating material.

The rotor core 7 includes a rare earth bonded magnet. Rare earth bonded magnets are made by mixing rare earth magnetic powder and an organic binder. As the rare earth bonded magnet, for example, a samarium iron nitrogen magnet, a neodymium magnet, or the like can be used. The rotor core 7 is integrally molded with the rotating shaft 5 or is fixed thereto. Note that the operating rotational speed of the electric blower 200 is 50,000 to 200,000 cycles/min.

Note that in this embodiment, a permanent magnet is used for the rotor core 7, but the present invention is not limited to this, and a reluctance motor, which is a type of commutatorless motor, or the like may be used.
A bearing 11 is provided between the impeller 1 and the rotor core 7. A bearing 12 is provided on the opposite side of the rotor core 7 in the direction of the rotating shaft 5 of the bearing 11 . A bearing 11 on one side of the rotating shaft 5 and a bearing 12 on the other side rotatably support the rotating shaft 5.

The motor housing 6 on the side closer to the impeller 1 supports the bearing 11, and the motor housing 10 on the side farther from the impeller 1 supports the bearing 11. The motor housing is made of metal, and by using aluminum as the material, it is possible to improve cooling performance through heat conduction and reduce weight. Note that the motor housing may be made of resin instead of metal, and in the case of resin, cooling of the bearing is promoted by providing a metal support between the bearing and the motor housing. Further, the motor housing may be made of aluminum or a steel plate.

A spacer 16 is installed at the end of the rotor core 7 to fix the rotor core and the bearing in the axial direction.
In addition, the amount of unbalance of the rotating body can be adjusted to a minimum by installing a magnet cover 14 provided on the outer periphery of the magnet and a resin balance adjusting material at the end of the magnet. There is. Thereby, the noise and vibration of the electric blower 200 are reduced.
Further, the motor housing 6 on the side closer to the impeller 1 and the motor housing 10 on the side farther from the impeller 1 have the same shape, and are installed so as to sandwich the stator core 8 in the axial direction. The inner walls of the cylinders are stacked in the axial direction and assembled by gluing or press-fitting. The stator core 8 is in contact with the two motor housings, and has an exposed portion 8a exposed from the motor housing approximately at the center of the stator core 8. By adopting such a stator core 8 and motor housing structure, the heat generated by the stator core can be cooled by thermal conduction through the motor housing and forced cooling in the exposed portion 8a, enabling cooling with high heat generation density and low loss. becomes. Note that the circumferential positions of the openings provided in the circumferential direction of the motor housing may be the same circumferential position or different circumferential positions. By using motor housings with the same structure, we are able to reduce costs and improve cooling performance.

On the outer periphery of the impeller-side housing 2 on the side of the impeller 1 (the side closer to the impeller 1), projections 35 are provided at three locations in the circumferential direction. A claw portion 22 provided on the outer periphery of the housing 9 (the shroud surface of the second axial flow diffuser blade) on the side opposite to the impeller 1 (the side far from the impeller 1), and The protrusion 35 of the first axial flow diffuser) is fitted and connected. Also, the number of blades of the axial diffuser blade 23 on the side of the impeller 1, the number of claws 22 at the end of the housing 9 on the side opposite to the impeller 1, and the number of protrusions 35 on the housing 2 on the side of the impeller 1. The number of blades and the protrusion 35 are the greatest common divisor of three. In this way, the circumferential positions of the axial diffuser blades 23 and the second axial diffuser blades 24 on the side of the impeller 1 are set at predetermined circumferential positions, thereby improving mass productivity. The greatest common divisor of the number of blades and the protrusion 35 may be greater than 1, but it is best if the number is the same as the number of protrusions.

In the fan casing 3 that covers the impeller 1 shown in FIG. 1B, the lower end 3a of the fan casing is inserted into the fitting part 28 of the housing 2 on the side of the impeller 1, and is adhesively fixed to the housing 2. Furthermore, a vibration isolating rubber 21 shown in FIG. 1B is installed in the fan casing 3 at the installation part of the cleaner main body 100. By providing the anti-vibration rubber 21, vibration of the electric blower 200 is suppressed and air leakage between the fan casing 3 and the installation part of the cleaner body 100 is prevented, thereby reducing noise and increasing efficiency. I'm trying.

Here, the impeller-side housing 2 is assembled and fixed from the impeller side to a threaded portion provided in a separately assembled motor housing 6 of the electric motor. Further, the impeller 1 is inserted into the rotating shaft 5 of the electric motor and fixed with screws. The fan casing 3 is inserted into the fitting part 28 of the housing 2 on the impeller side and bonded with adhesive. Thereafter, the electric motor assembly integrated with the fan casing is assembled to the claw part of the housing 9 on the side opposite to the impeller, and is bonded by pouring adhesive into the housing fitting part 37. That is, by assembling the electric motor and the blower from the upstream direction of the impeller, it is possible to improve assembly efficiency during mass production.

In addition, the fitting part 28 between the fan casing 3 and the impeller side housing is provided with a slight gap in the axial direction and circumferential direction to allow for misalignment of the impeller, and by adjusting it during assembly, By adjusting the axis of the impeller and fan casing, it is possible to increase efficiency and improve mass productivity.

Here, in the electric motor excluding the rotating shaft, the electric motor axial length Lm connecting the upper and lower ends of the motor housing forming the outer circumference is approximately the diffuser axial length Ld from the impeller outlet to the exhaust port. They have the same length and are shorter than the length Lf in the axial direction of the blower from the suction port to the exhaust port. Note that the ratio of the axial length Lf of the blower to the axial length Lm of the electric motor is about 3:2, and the axial length Lf of the blower and the axial length Lm of the electric motor are installed so as to overlap in the axial direction. By realizing this configuration, the flow of cooling air can be introduced into the motor with low loss by utilizing the venturi effect at the diffuser outlet, making it possible to realize a small and highly efficient electric blower. It becomes possible.

At the design point of the axial diffuser blade 23 on the side of the impeller 1, the flow outflowing from the impeller 1 and the blade inlet angle are made to substantially match, thereby reducing pressure loss. As a result, the axial diffuser blades 23 reduce the rotational velocity component of the flow, thereby enhancing the diffuser effect and improving the blower efficiency. Further, the second axial diffuser blade 24 installed axially downstream of the axial diffuser blade 23 further reduces the rotational velocity component of the flow discharged from the axial diffuser blade 23. This increases the deceleration of the air flow in the direction of the rotating shaft 5 and further improves the efficiency of the blower.

<Air flow within electric blower 200>
Next, the flow of air within the electric blower 200 will be explained.
When the electric motor section 202 shown in FIG. 1B is driven to rotate the impeller 1, air flows in from the air suction port 4 of the fan casing 3 and into the impeller 1. In the case of a diagonal flow type impeller, the incoming air is pressurized within the impeller 1 and gives a radial component to the flow sucked in from the direction of the rotating shaft 5, generating a flow inclined from the direction of the rotating shaft 5. . In this way, at the impeller outlet 1a, the flow becomes a flow having a rotation direction component and a direction component of the rotation axis 5, and flows out from the impeller 1.

When the airflow flowing out from the impeller 1 passes through the first axial diffuser blade 23 and the second axial diffuser blade 24, it flows along the blades (23, 24), causing rotation of the flow. The directional velocity component is reduced. Further, the lower end 9c of the inner wall of the housing 9 on the side opposite to the impeller is located upstream of the trailing edge 24d of the second axial flow diffuser blade 24 (the lower end 9c of the inner wall of the housing 9 on the side opposite to the impeller By protruding the trailing edge 24d of the diffuser blade 24), the flow path expands radially inward in the latter half of the second axial flow diffuser blade 24, thereby generating a radially inward flow and eliminating exhaust gas. (the flow expands in the direction where there is no inner wall). This facilitates the flow into the opening 20 of the motor housing 10. Note that the first flow path 18 is a flow path from the air suction port 4 of the fan casing 3 to the exhaust portion 32 of the housing 9, as shown by the solid arrow α1 in FIG. 1B.

In the first flow path 19, since the exit wind speed of the second axial flow diffuser blade 24 is high, a flow toward the outlet of the second axial flow diffuser blade 24 is generated within the second flow path due to the Venturi effect. The flow toward the outlet of the second axial diffuser blade 24 in the second flow path is sucked in from the opening 20 of the motor housing 10, and flows between the vicinity of the bearing 12 on the side opposite to the impeller inside the motor and between the coils arranged in the circumferential direction. By passing through, the bearing 12 and the coil on the side opposite to the impeller are cooled. Furthermore, the flow that has passed between the coils passes around the bearing 11 on the impeller side, passes through the opening 15 of the motor housing 6, and passes through the radial gap between the motor housing 6 and the inner wall 2a of the housing on the impeller side. It heads downstream (to the outlet of the axial diffuser blade 24) and merges with the first flow path. The stator core 8 is cooled with low loss by passing cooling air through the radial gap between the motor housing 6 and the inner wall 2a of the housing 2 on the impeller side.

By merging the first flow path and the second flow path near the second axial flow diffuser blade 24, it is possible to efficiently utilize the Venturi effect, reduce pressure loss inside the electric motor, and cool the inside of the electric motor. I have to. That is, since the flow direction is not changed by the structure when taking in cooling air for the electric motor, the blower efficiency can be maintained at a high level even at non-design points, and high efficiency can be achieved over a wide range of operation.

<Blower section 201>
Next, the configuration of the blower section 201 of the first embodiment will be explained.
FIG. 2A is a perspective view of the impeller 1 of the first embodiment, and FIG. 2B is a sectional view of the impeller 1.
3A is a view of the housing 2 having the axial diffuser blade 23 on the impeller 1 side, viewed from the impeller side, FIG. 3B is a longitudinal sectional view, and FIG. 3C is a partial sectional view viewed from the outer periphery of the housing. It is.
4A is a view of the housing 9 having the axial diffuser blade 24 on the side opposite to the impeller 1, viewed from the impeller side, FIG. 4B is a longitudinal cross-sectional view, and FIG. 4C is a partial cross-section viewed from the outer periphery of the housing. It is a diagram.
FIG. 5A is an external view of the electric motor 400 seen from the side, and FIG. 5B is a longitudinal cross-sectional view.
Note that FIGS. 3C and 4C are partial cross-sectional views with the shroud removed to show the shape of the diffuser blades (23, 24).

<Impeller 1>
First, an impeller 1 of a rotary blade according to an embodiment of the present invention will be described using FIGS. 2A and 2B.
The impeller 1 includes a hub plate 26 and a plurality of blades 27. The hub plate 26 and the blades 27 are integrally molded from engineering plastic or thermoplastic resin.

A convex portion 26a (see FIG. 2B) is provided on the back side of the hub plate 26. By rotating the impeller 1 and scraping the convex portion 26a, the balance of the impeller 1 can be corrected. Thereby, the amount of unbalance of the impeller 1 can be reduced, and vibration and noise can be reduced.
Furthermore, a metal sleeve 13 (see FIG. 2B) is provided as an integrally molded product on the back side of the hub plate 26. By using the sleeve 13, it is possible to reduce the variation in the fitting gap between the shaft and the impeller that occurs when there is no sleeve, and by reducing the unbalance of the impeller, it is possible to reduce vibration and noise. Further, by installing a metal sleeve 13 on the boss portion of the impeller, the heat generated by the bearing 11 is transferred to the sleeve, thereby making it possible to promote the cooling performance of the bearing due to the rotation of the sleeve.

When removing burrs from the resin of the impeller 1 and the resin of the fan casing 3 during assembly, improve the sliding properties of the resin on the impeller side (by scraping the impeller). By performing a break-in operation, it is possible to minimize the gap between the fan casing 3 and the fan casing 3.
On the other hand, if the amount of deformation of the blades due to centrifugal stress during operation of the impeller 1 is large, a material with a small Young's modulus may be used for the fan casing so that the resin of the fan casing is scraped. The gap between the fan casing and the fan casing can be minimized, making it possible to use a highly efficient electric blower.

The impeller 1 is a mixed flow impeller in which the boss curved surface 29a extends around the outer circumferential portion of the impeller and is inclined in the direction of the rotating shaft 5 (downward in FIG. 2B). Although FIGS. 2A and 2B show the impeller 1 as an open mixed flow impeller without a shroud plate, a centrifugal impeller may be used with or without a shroud plate.

Next, the blower 201 of the first embodiment will be explained.
As shown in FIG. 1B, an exemplary blower 201 includes 15 first (impeller side) axial flow diffuser blades 23 arranged at equal intervals in the circumferential direction on the downstream side of the impeller 1 in the axial direction. . The first axial diffuser blade 23 is provided between the inner wall 2a and the outer wall 2b of the housing 2 on the side of the impeller 1, and is molded integrally with the housing 2. The second axial diffuser blade 24 is installed between the inner wall 9a and the outer wall 9b of the anti-impeller housing 9, and is integrally molded with the housing 9. Further, the number of blades of the second axial flow diffuser blades 24 is 15, which is the same as the number of blades of the axial flow diffuser blades 23 on the impeller 1 side.

The circumferential positions of the shroud side (outer circumferential side) trailing edge 23d of the impeller side diffuser blade 23 and the shroud side (outer circumferential side) leading edge 24c of the second axial flow diffuser blade 24 shown in FIG. 3 are approximately the same in the circumferential direction. We are doing so.
Efficiency on the low air volume side can be improved by making the circumferential positions of the trailing edge 23d of the impeller side diffuser blade 23 and the leading edge 24c of the second axial flow diffuser blade 24 substantially coincide with each other. In order to improve the efficiency on the large air volume side, the (23, 24) pitch between the blades is preferably 15 to 50% (360/Zd).

As shown in FIG. 1B, the inner wall (hub) 2a of the first axial diffuser blade 23 and the inner wall (hub) 9a of the second axial diffuser blade 24 substantially match. Here, it is desirable that the inner wall 2a of the first axial diffuser blade 23 and the inner wall 9a of the second axial diffuser blade 24 be flush with each other. For example, if the inner wall 9a of the housing 9 after merging is large and the diameter of the hub surface is large and protrudes into the flow path, the loss in the axial diffuser blades 23 and 24 will increase.

As shown in FIG. 1B, the inner wall 2a of the housing 2 on the side of the impeller 1 and the inner wall 9a of the housing 9 on the opposite side of the impeller are installed without any gap in the axial direction.
The outer wall 2b of the housing 2 on the side of the impeller 1 and the outer wall 9b of the housing 9 on the opposite side of the impeller are fixed in the circumferential direction by the fitting part 37 to bring out the center of each housing 2, and by the claw part 22 on the outer periphery of the housing 9. By doing this and fixing with adhesive, the structure is easy to assemble, and mass productivity is improved.

The shape in the height direction of the axial diffuser blade 23 on the impeller 1 side shown in FIGS. 3A to 3C extends from the inner wall 2a to the outer wall 2b of the housing 2 on the impeller side, and ) (see FIG. 1B), and curves in the height direction from near the center in the radial direction to the outer periphery, with an inclination that returns upstream in the direction of the rotating shaft 5.

As shown in FIG. 3C, the chord length of the shroud side of the axial diffuser blade 23 on the impeller 1 side (the line connecting the leading edge 23c and the trailing edge 23d) is the same as that of the hub side (inner wall 2a side). It is long compared to the wing chord length. In addition, since the wind speed on the shroud side at the outlet of the impeller 1 is high, the blade chord length on the shroud side is made to have a gentle shape to suppress loss and improve efficiency. In addition, by curving the axial diffuser blade 23 in the height direction, secondary flow occurs on the blade surface (the surface of the axial diffuser blade 23) on the hub side (inner wall 2a side) of the diffuser and the hub surface (inner wall 2a). can be suppressed. Therefore, peeling inside the diffuser (the blade surface on the inner wall 2a side of the axial diffuser blade 23 and the inner wall 2a) can be suppressed, and high efficiency can be achieved.

As shown in FIG. 4, the second axial diffuser blade 24 becomes thicker toward the exhaust port 32 (blade thickness on the trailing edge side of the blade), and the axial diffuser blade 24 on the impeller 1 side becomes thicker as it approaches the exhaust port 32. (see Figure 4).

The chord length of the second axial diffuser blade 24 shown in FIG. 4 is approximately the same as the chord length of the shroud side of the axial diffuser blade 23 on the impeller side. By increasing the chord length of the second axial flow diffuser blade 24 and increasing the blade thickness toward the trailing edge of the second axial flow diffuser blade 24, as shown in FIG. 4C, the flow deceleration is gradually reduced. This allows for improved static pressure recovery and higher efficiency.

Here, the shapes of the axial diffuser blades 23 and 24 will be explained.
The first (on the impeller 1 side) axial flow diffuser blade 23 and the second (on the side opposite to the impeller 1) axial flow diffuser blade 24 have a chord length shown in FIG. The blade shape has a solidity in which the solidity obtained by dividing the straight line length connecting the trailing edge 23c and the trailing edge 23d by the distance along the circumferential direction of the blade mounting interval is less than 1. Note that if the solidity is smaller than 1, it can be manufactured with a mold configuration that molds in the direction of the rotating shaft 5, and high efficiency and productivity can be achieved.

Further, the end 9c of the inner wall of the second axial diffuser blade 24 is located upstream from the trailing edge of the second axial diffuser blade 24 (the end 9c of the inner wall of the second axial diffuser blade 24 By protruding the trailing edge of the diffuser blade 24), the flow path expands radially inward in the latter half of the second axial flow diffuser blade 24, thereby generating a radially inward flow and exhausting the air. . This promotes the flow into the opening 20 of the motor housing 10 and improves cooling performance.
The axial position of the trailing edge 24d of the second axial flow diffuser blade 24 is such that it is located between the radial openings 20 of the housing 10 on the anti-impeller side, so that It is possible to generate a flow and improve cooling performance.
That is, the electric blower 200 of the first embodiment can maintain high efficiency over a wide operating range. Therefore, it is possible to provide a vacuum cleaner 300 (see FIG. 7) that has high suction power over a wide range.

In the first embodiment, as an example, the opening of the motor housing 10 shown in FIG. 1B has a radial opening 20 and an axial opening 34, but the opening may be in either one direction, and both the radial direction and the axial direction are compatible. A slanted opening may also be used.

According to the electric blower 200 of the first embodiment described above, the rotating rotor, the stator core and the coil on the outer circumference of the rotor, and the impeller side so that a part of the outer circumference of the stator core approximately at the axial center is exposed. an electric motor having a motor housing installed from both directions on the side opposite to the impeller; a first axial diffuser blade having circumferential blades axially downstream of the impeller; and a blower having a second axial diffuser blade. and the electric motor is formed as a separate assembly from the blower, and the impeller-side housing integral with the first axial diffuser blade is fixed to the impeller-side motor housing, and the impeller-side housing is fixed to the impeller-side motor housing, and The side motor housing is arranged so as to cover the impeller side motor housing from upstream to a substantially central position in the longitudinal direction of the impeller side motor housing, and the anti-impeller side housing having the second axial flow diffuser blade is disposed so as to cover the impeller side motor housing from upstream to approximately the center position. The two motor housings have a plurality of openings disposed in a radial direction, and are arranged downstream from approximately the center in the longitudinal direction of the motor housing on the vehicle side so as to cover the motor housing on the anti-impeller side, and the two motor housings have a plurality of openings installed in the radial direction. The inner wall of the housing on the impeller side has a gap in the radial direction with the motor housing, and the opening of the motor housing on the anti-impeller side is located at a position overlapping the second axial flow diffuser blade in the axial direction. shall be.

Thereby, it is possible to provide the electric blower 200 that is highly efficient in a wide air volume range, and is small and lightweight. Therefore, it is possible to cool the stator (8) and bearings 11 and 10 of the electric motor 202, and to obtain a vacuum cleaner 300 that is small in size and has improved suction power in a wide air volume range.

<<Second embodiment>>
Next, a second embodiment will be described using FIG. 6.
FIG. 6 is a longitudinal cross-sectional view of an electric blower 200 according to a second embodiment of the present invention.
The electric blower 200 of the second embodiment differs from the electric blower 200 of the first embodiment in that the second flow path passes through the axial opening of the motor housing 10 on the side opposite to the impeller, and the second flow path passes through the opening in the axial direction of the motor housing 10 on the side opposite to the impeller 1. 2 and the axial clearance flow path 30 of the motor housing 6. In addition, the cooling air that has passed through the axial gap flow path 30 passes through the radial gap between the motor housing 6 and the housing 2, and passes between the axial diffuser blade 23 on the impeller side and the axial diffuser blade 24 on the anti-impeller side. It passes through a connecting gap 31 that connects to the flow path, and then passes through a flow path that merges with the axial diffuser blade 24.
The electric blower 200 has the same basic configuration as the first embodiment, so the same elements are denoted by the same reference numerals and the explanation thereof will be omitted.

The flow in the second flow path 19 is caused by the high wind speed at the inlet of the axial diffuser blade 24 on the anti-impeller side, which lowers the static pressure, and due to the Venturi effect, the flow passes from the inside of the motor through the connection gap 31 and flows toward the anti-impeller side. A flow toward the inlet of the axial diffuser blade 24 is generated. The flow through the connection gap 31 flows into the motor through the openings 20 to 34 of the motor housing 10 of the anti-impeller, passes through the motor, passes through the axial opening 33 of the motor housing 10, and connects the housing 2 and the motor. It passes through an axial gap flow path 30 between the housing 6 and the housing 6 . Thereafter, the cooling air that has passed through the axial gap flow path 30 passes through the radial gap between the motor housing 6 and the housing 2, and is then passed between the axial diffuser blade 23 on the impeller side and the axial diffuser blade 24 on the anti-impeller side. It passes through a connecting gap 31 that connects to the axial flow diffuser blade 24 .
The flow in the second flow path 19 cools the bearing 11 on the side opposite to the impeller 1 by being sucked into the motor section 202, and cools the stator core 8 and the windings by flowing around the outer circumferential side of the stator core 8. , which cools the bearing 12 on the impeller side and flows into the connection gap 31.

Note that the second flow path configuration without the axial gap flow path shown in the first embodiment may be used in combination. Even in this case, the cooling air can pass through the radial opening 15 of the motor housing 6 on the impeller side and flow into the connection gap 31, so that the motor can be cooled.
Further, the connection gap 31 is formed by the inner wall 2a of the motor housing 2 on the side of the impeller 1 and the motor housing 9 on the side opposite to the impeller 1, and the connection part 28 is connected from the outer peripheral part of the stator core 8 to the first flow path 17. As one goes toward the second axial diffuser blade 24, the second axial diffuser blade 24 side is formed of a rear inner wall 9a, which is inclined toward the axial direction. Thereby, the air flow flowing through the connecting portion 28 can smoothly merge with the air flow flowing through the first flow path 18, and the air volume can be increased.

The flow that has flowed into the first flow path 18 from the connection gap 31 merges with the flow pressurized by the impeller 1, flows to the second (anti-impeller side) axial flow diffuser blade 24, and is exhausted from the exhaust port 32. Ru. Note that the amount of air passing through the second axial diffuser blade 24 is the sum of the amount of air passing from the impeller 1 through the first axial diffuser blade 23 and the amount of air flowing from the second flow path 18 through the connection gap 31, and The maximum air volume is achieved inside the blower 200.

In the second axial diffuser blade 24, a trailing vortex is likely to occur at the trailing edge of the first axial diffuser blade 23 at a non-design point where the air volume is small, and the inlet flow of the first axial diffuser blade 24 is It tends to get complicated. However, in the second axial diffuser blade 24 of this configuration, the air volume from the connection gap 31 merges with the axial diffuser blade 23 on the impeller side and flows to the second axial diffuser blade 24 .

This increases the air volume inside the second axial diffuser blade 24 even at the non-design point. Therefore, separation inside the second axial diffuser blade 24 is suppressed, and the blower efficiency is improved. Note that the amount of air flowing from the opening 20 of the second motor housing 10 toward the connection gap 31 is greater on the large air amount side where the air amount at the outlet of the first (impeller 1 side) axial flow diffuser blade 23 increases. Therefore, with this configuration, the efficiency of the blower on the large air volume side can be improved, and high efficiency can be achieved over a wide range of operation.

According to the electric blower 200 of the second embodiment described above, there is a rotating rotor, a stator core and a coil on the outer circumference of the rotor, and an impeller side and an anti-impeller side so that a part of the outer circumference of the stator core is exposed. an electric motor having a motor housing installed from both sides, a first axial diffuser blade having circumferential blades axially downstream of the impeller, and a blower having a second axial diffuser blade; The electric motor is formed as a separate assembly from the blower, and the impeller-side housing integral with the first axial diffuser blade is fixed to the impeller-side motor housing, and the impeller-side motor housing is fixed to the impeller-side motor housing. The housing is disposed so as to cover the motor housing on the impeller side from upstream to approximately the center position in the long axis direction, and the housing on the anti-impeller side having the second axial flow diffuser blade is arranged so as to cover the motor housing on the impeller side from upstream to approximately the center position. The two motor housings have a plurality of openings installed in the radial direction, and are arranged downstream from the center in the longitudinal direction of the housing to cover the motor housing on the side opposite to the impeller. The inner wall of the housing has a gap in the radial direction with the motor housing, the opening of the motor housing on the side opposite to the impeller is located downstream of the second axial diffuser blade, and the motor housing on the side of the impeller is located downstream of the second axial diffuser blade. a gap in the axial direction between the motor housing on the impeller side and the housing on the impeller side, and an axial flow diffuser blade on the impeller side and an axial flow on the anti-impeller side. It has an electric blower with a connecting channel between the diffuser blades.

Thereby, it is possible to provide the electric blower 200 that is highly efficient in a wide air volume range, and is small and lightweight. Therefore, the stator (8) and bearing 11 of the electric motor unit 202 are cooled, and the vacuum cleaner 300 is small and has improved suction power in a wide air volume range.

Note that the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the embodiments described above are described in detail to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace some of the configurations of each embodiment with other configurations.

1 Impeller 2 Impeller side housing 2a Inner wall of impeller side housing (first axial flow diffuser)
2b Outer wall of the housing on the impeller side (first axial diffuser)
3 Fan casing 3a Lower end of fan casing 4 Air suction port (suction port)
5 Rotating axis (axis)
6 Motor housing (impeller side)
7 Rotor core (rotor)
8 Stator core (stator)
9 Housing on the anti-impeller side 9a Inner wall of the housing on the anti-impeller side (hub surface of the second axial diffuser blade)
9b Outer wall of the housing on the anti-impeller side (shroud surface of the second axial diffuser blade)
9c Lower end of inner wall of housing on anti-impeller side 10 Motor housing (opposite impeller side)
11 Bearing (impeller side bearing)
12 Bearing (bearing on the anti-impeller side)
13 Sleeve 14 Magnet cover 15 Opening (motor housing opening on impeller side)
16 Spacer 17 Coil 18 First flow path 19 Second flow path 20 Opening (motor housing opening on the side opposite to the impeller)
21 Anti-vibration rubber 22 Claw portion 23 Impeller side diffuser blade (first axial diffuser)
24 Diffuser blade on the anti-impeller side (second axial diffuser)
26 Impeller hub 27 Impeller blades 28 Fitting portion 29 Impeller boss 30 Axial gap flow path 31 Connection gap 32 Exhaust port 33 Axial opening of impeller side motor housing 34 Opposite impeller side motor housing 35 Projection 36 Fastening portion with motor 37 Housing fitting portion 40 Electric motor 200 Electric blower 201 Air blower 202 Electric motor 300 Vacuum cleaner

Claims (2)

A rotor having a rotor core, a stator having a stator core and having a coil wound thereon,
an electric motor including a motor housing housing the rotor and the stator;
an impeller disposed on the upstream side of the motor housing;
a first axial diffuser blade disposed downstream of the impeller;
a second axial diffuser blade disposed downstream of the first axial diffuser blade;
an anti-impeller side housing having an inner wall, an outer wall, and the second axial diffuser blade formed between the inner wall and the outer wall,
The first axial diffuser blade is fixed so as to be located upstream from the center of the motor housing, and is arranged to surround the motor housing from upstream to approximately the center position in the longitudinal direction of the motor housing. is,
The second axial diffuser blade is arranged to surround the motor housing from approximately the center to downstream in the longitudinal direction of the motor housing ,
The motor housing has an upstream opening formed upstream of the rotor core, and a downstream opening formed downstream of the rotor core,
the downstream edge of the inner wall is located upstream of the trailing edge of the second axial diffuser blade and the downstream opening;
An electric blower characterized in that the axial position of the trailing edge of the second axial diffuser blade is within the axial position of the downstream opening. The electric blower according to claim 1,
A protrusion is provided in the circumferential direction on the outer periphery of the first axial diffuser blade,
A claw portion is provided on the outer periphery of the second axial diffuser blade,
The electric blower is characterized in that the protrusion and the claw are connected by being fitted together.

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