JPH11125198A - Motor-driven blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a motor-driven blower which simplifies its cooling constitution to prevent its efficiency from being degraded. SOLUTION: An electric motor driving a blower is formed into a DC brushless type one with a rotor having neither coil nor commutator, the evolution of heat by the rotor 1 is reduced, it is thereby eliminated to let air flow pass through the inside of the electric motor out of an air guide 13, and loss in passing pressure is reduced so as to allow its efficiency to be enhanced as compared with a case that air flow passes through the inside of the electric motor. Besides, cooling the inside of the electric motor can be performed by way of a frame 7 by letting air flow emitted out of the air guide 12 pass through the outer circumference of the electric motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric blower used for a vacuum cleaner or the like.

[0002]

2. Description of the Related Art Electric blowers used for electric vacuum cleaners are:
Most use AC commutator motors. Since this motor is relatively inefficient and generates a large amount of heat, it was necessary to cool the motor. This type of electric blower will be described with reference to FIG. In the figure, reference numeral 101 denotes an electric motor, and an impeller 102 constituting a part of a blower unit is fixed to a rotating shaft 103 of the electric motor 101. The blower unit includes, in addition to the impeller 12, an air guide 104 disposed on the outer periphery of the impeller 102 and a fan casing 110 that includes the impeller 102 and the air guide 104. The air guide 104 has a function of recovering the pressure of the airflow from the impeller 102, and has a plurality of passages (channels) partitioned by a plurality of blades.

Since the motor 101 needs to rotate at a high speed, an AC commutator type is usually used. This motor has a rotor 105 to which a rotating shaft 103 is fixed, and a winding 107 is wound around the rotor 105 as shown in FIG. Therefore, a commutator 106 is provided. A stator 10 for rotating the rotor 105 is provided on the outer periphery of the rotor 105.
9 are arranged.

As described above, since the rotor 105 has the winding 107, when a current flows through the winding 107, Joule heat is generated, and the heat generated by the rotor 105 increases. Therefore, in order to cool the rotor 105,
The airflow that has exited from the air guide 104 is again returned to the inside (the
3), the air passes through a ventilation path 108 provided inside the electric motor 101 as indicated by an arrow.

[0005]

However, in the configuration of the conventional electric blower, since the airflow coming out of the air guide 104 is made to pass through the inside of the electric motor 101, the passage pressure loss of the airflow becomes large and the efficiency is reduced. There was a problem that. In particular, in order to cool the rotor 105 efficiently, the cooling wind is largely bent toward the rotating shaft 103 as shown by an arrow so that the cooling wind is introduced from a portion near the rotor 105. Therefore, there is also a passage pressure loss due to a large bending of the direction of the cooling air, which has a problem of further reducing the efficiency of the electric blower.

Further, since the motor 101 generates a large amount of heat, the stator 10 is required to secure a sufficient size of the ventilation passage 108.
It is necessary to provide the ventilation passage 108 between the motor 9 and the motor frame 111. Therefore, the shape of the core of the stator 109 is set to a substantially square shape. As described above, since it is difficult to use a round core as the core of the stator 109, the loss of the stator 109 is increased. Conversely, if the core of the stator 109 is made to be round, In order to secure a ventilation path between the core and the frame 111, the shape of the frame 111 becomes large and the weight increases.

SUMMARY OF THE INVENTION [0007] In view of the above-mentioned problems, an object of the present invention is to provide an electric blower in which the pressure loss of an airflow is reduced to improve the efficiency.

[0008]

In order to achieve the above object, the present invention provides an electric motor comprising: a rotor having a magnet; a stator for generating a magnetic field for rotating the rotor;
A frame that contains the rotor and the stator, and a ventilation path that allows the airflow from the blower unit to flow along the outer periphery of the frame. According to this configuration, the airflow path is wound around the rotor of the motor unit. Since no wires are used, heat generation in the rotor can be suppressed, and the cooling configuration of the motor unit can be simplified. In other words, the amount of heat generated by the electric motor can be greatly reduced, so that it is not necessary to allow the cooling air to pass through the frame of the electric motor. Further, since the airflow from the blower flows along the outer periphery of the frame of the electric motor, the flow direction of the airflow does not largely change as in the related art, so that the passage pressure loss can be further reduced.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 of the present invention comprises a motor section and a blower section driven by the motor section, wherein the motor section includes a rotor having a magnet, and a rotor having a magnet. A stator that generates a magnetic field for rotation, and a frame that includes the rotor and the stator, and has a ventilation path that allows airflow from the blower unit to flow along the outer periphery of the frame. According to this configuration, since no winding is used for the rotor of the motor section, heat generation in the rotor can be suppressed, and the cooling configuration of the motor section can be simplified. In other words, the amount of heat generated by the electric motor can be significantly reduced, so that it is not necessary to allow the cooling air to pass through the frame of the electric motor, so that the ventilation pressure loss is reduced and the efficiency can be increased. . Further, since the airflow from the blower flows along the outer periphery of the frame of the electric motor, the flow direction of the airflow does not largely change as in the related art, so that the passage pressure loss can be further reduced. Further, the airflow from the blower unit flows along the frame, so that the electric blower unit can be cooled through the frame.

According to a second aspect of the present invention, the cross-sectional area of the ventilation path in the first aspect of the invention is gradually increased,
Pressure recovery is performed. According to this configuration,
The dynamic pressure of the wind blown from the blower unit can be restored to the static pressure, and the efficiency of the electric blower can be improved.

According to a third aspect of the present invention, there is provided a blower unit according to the first aspect, wherein the blower unit is disposed on an outer periphery of the impeller fixed to a rotating shaft of a rotor,
An air guide having a plurality of independent diffusers,
A fan case enclosing the impeller and the air guide and comprising a fan case fixed to a frame, and a plurality of channels connected to a diffuser portion of the air guide in an air passage for flowing airflow from the air guide along the frame. It has a diffuser part, and is configured to recover the dynamic pressure to the static pressure. According to this configuration, the pressure recovery can be effectively realized by the diffuser part of a plurality of channels,
The efficiency of the electric blower is improved.

According to a fourth aspect of the present invention, there is provided an electric motor driving element according to any one of the first to third aspects of the present invention, which is provided in an air passage. In addition, the driving element can be effectively cooled, and a compact configuration can be realized.

[0013]

【Example】

(Embodiment 1) An embodiment of the present invention will be described with reference to FIGS. The figure shows an electric blower used for a household vacuum cleaner or the like, and is composed of a blower unit and an electric motor unit.

In FIG. 1, reference numeral 1 denotes a rotor, which constitutes a part of a motor unit. The motor part is, besides the rotor 1,
It comprises a stator 5 for generating a magnetic field for rotating the rotor 1, and a frame 7 containing the stator 5 and the rotor 1. Further, the rotor 1 is provided with a rotating shaft 4, which is supported by bearings 10, 11 attached to brackets 8, 9 constituting the upper and lower parts of the frame 7. As shown in FIG. 2, a magnet 2 is provided on the outer periphery of the rotor 1, and a stator 5 is arranged with a gap provided between the magnet 2 and the stator 5. 7, and the core 6 is wound with a winding 6.

[0015] The blower unit provided above the electric motor unit includes:
A centrifugal impeller 12 having a plurality of blades, an air guide 13 arranged on the outer periphery of the impeller 12,
It comprises a fan case 15 containing an air guide 13 and an impeller 12. Impeller 12 of blower section
Is connected to the distal end side of the rotating shaft 4 of the electric motor unit, and the rotation of the electric motor unit causes the impeller 12 to rotate at high speed.

The air guide 13 has an independent diffuser section 14 having a plurality of channels, and gradually reduces the airflow discharged from the impeller 12 to recover the pressure. In addition, an intake port 16 through which air flows in is provided in the upper central portion of the fan case. Fan case 1
5 is press-fitted and fixed to the outer periphery of the bracket 8 of the electric motor.

The diffuser portion 1 of the air guide 13
A communication port 17 that is open to the outside of the motor, that is, to the outer peripheral side of the frame 7 is provided in the bracket portion 8 outside the frame 4. A cylindrical case 18 connected to the fan case 15 is fixed to the outer periphery of the frame 7, and forms a ventilation path 19 with the frame 7.

Next, the operation will be described. In the motor unit for driving the impeller, the rotor 1 is composed of the magnet 2, and when the winding 6 wound on the stator 5 is excited, a rotating magnetic field is generated, and the rotor is synchronized with this magnetic field. 1 rotates.
In order to generate a rotating magnetic field, it is necessary to apply an alternating voltage to the stator 5 side, and a power supply is configured by an inverter circuit that sequentially drives semiconductor switching elements (not shown).

The above-mentioned electric motor is called a brushless motor. This type of brushless motor generates less heat than an AC commutator motor having a commutator, and does not need to supply power by mechanical contact. It is sufficient to cool the stator side.

The airflow generated by rotating the impeller 12 at a high speed is sucked through the intake port 15 and recovered by the diffuser 14 of the air guide 13 at the expanded pressure. The airflow from the diffuser 14 passes through a communication port 17 provided on the outer periphery of the bracket 8 and is guided to a ventilation path 19,
The motor frame 7 is cooled and exhausted.

As compared with the case where the conventional AC commutator motor is used, there is no need to flow air into the motor, and it is necessary to provide a ventilation path between the frame 7 and the stator 5 as shown in FIG. And a compact motor is constructed.
In addition, in order to guide the airflow that has flowed out of the diffuser section 14 into the motor, it is not necessary to bend the airflow again, so that the passage pressure loss is reduced and the efficiency is improved. The stator 5 generates a little heat because the winding 6 is wound therearound.
Since the core is closely attached to the frame 7, it can be efficiently cooled by the airflow flowing through the ventilation path 19 through the frame 7. Also, the stator 5 can be disposed in the frame 7 without considering the ventilation path.
A more compact and small iron loss structure can be realized with a core close to a perfect circle. Further, since the amount of generated heat is small, the frame 7 can have a fully-closed structure, and durability and safety are improved.

(Embodiment 2) An embodiment of the second aspect of the present invention will be described with reference to FIG. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 3, reference numeral 20 denotes an air passage formed by a cylindrical case 21 and a frame 7 of the electric motor, and a conical spacer 22 is mounted on the frame 7 side of the electric motor. The ventilation passage 20 has a structure in which the cross-sectional area increases as it goes downstream. The airflow that has passed through the communication port 17 is guided to the ventilation path 20, and is decelerated because its cross-sectional area increases as it goes downstream. That is, the airflow entering the diffuser portion 14 of the air guide 13 is
5, the pressure is continuously reduced gradually and the dynamic pressure is restored, thereby improving the efficiency of the electric blower.

(Embodiment 3) An embodiment of the third aspect of the present invention will be described with reference to FIG. The same components as those in the second embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 4, reference numeral 31 denotes a ventilation path diffuser provided between the ventilation path 30 and the frame 7 of the electric motor, and is continuous with the diffuser portion 32 of the air guide 13. The air flow sent out from the impeller 12 is first decelerated by the diffuser 32 of the air guide 13 to recover the pressure. Thereafter, the air flow is diffused continuously by the airway diffuser 31, and the pressure is recovered. That is, the airflow from the impeller 12 is gradually and continuously decelerated until reaching the exhaust holes 33, so that a very efficient pressure recovery is performed and an efficient electric blower can be realized.

(Embodiment 4) An embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 5, reference numeral 41 denotes a circuit board on which driving elements for driving the motor are arranged. Due to the nature of a brushless motor, which is a type of electric motor, an inverter circuit is necessary to generate a rotating magnetic field. Among them, a large current flows through the driving element, so that cooling is required. In the present embodiment, the circuit board 41 on which the driving elements are mounted is installed in the air passage 19, so that the circuit board 41 can be made compact. In this case, when the cylindrical case 40 is made of a metal having good heat transfer, the cooling effect can be further improved, and the shielding effect can be expected.

[0028]

According to the first aspect of the present invention, since no winding is used for the rotor of the motor, heat generation in the rotor can be suppressed and the cooling structure of the motor can be simplified. In other words, the amount of heat generated by the motor unit can be greatly reduced, so that it is not necessary to pass cooling air through the motor frame.
Since the ventilation resistance is reduced and the wind direction from the blower is not greatly bent so that cooling air flows to the rotor,
The ventilation resistance can be further reduced, and the efficiency of the electric blower can be increased. In addition, since the airflow from the blower unit flows along the frame, the electric blower unit can be cooled through the frame, and the efficiency can be further improved.

According to the second aspect of the present invention, by gradually increasing the cross-sectional area of the ventilation passage provided on the outer periphery of the frame of the electric motor portion, pressure recovery is performed even when flowing through the ventilation passage. Efficient operation becomes possible.

According to the third aspect of the present invention, pressure recovery can be achieved by partitioning the air passage into a plurality of passages, connecting each passage to a plurality of independent diffusers of the air guide, and forming a continuous diffuser. It can be performed more efficiently, and higher efficiency of the electric blower can be realized.

According to the fourth aspect of the present invention, by installing the driving element of the motor unit in the ventilation path, the driving element having a large amount of heat can be efficiently cooled by air cooling. The arrangement allows a compact cooling configuration.

[Brief description of the drawings]

FIG. 1A is a cross-sectional plan view showing an air guide and an impeller of an electric blower according to a first embodiment of the present invention. FIG. 1B is a front cross-sectional view of the electric blower. FIG.

FIG. 2 is a plan cross-sectional view around a rotor of the electric blower.

3A is a partial plan cross-sectional view showing an air guide and an impeller of an electric blower according to a second embodiment of the present invention. FIG. 3B is a cross-sectional view of the electric blower. FIG. 3C is a partial rear view of the electric blower viewed from the exhaust side. Figure

4A is a partial plan sectional view showing an air guide and an impeller of an electric blower according to a third embodiment of the present invention. FIG. 4B is a front sectional view of the electric blower. FIG. Rear view (d) Side sectional view showing the diffuser part of the electric blower

5A is a partial plan sectional view showing an air guide and an impeller of an electric blower according to a fourth embodiment of the present invention. FIG. 5B is a front sectional view of the electric blower. FIG. Rear view

6A is a partially cutaway front view of a conventional electric blower, and FIG. 6B is a cross-sectional plan view of the vicinity of a rotor of the electric blower.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotor 2 Magnet 4 Rotating shaft 5 Stator 7 Frame 12 Impeller 13 Air guide 19 Ventilation path 20 Ventilation path 31 Ventilation path diffuser 32 Diffuser

Claims (4)

[Claims] An electric motor comprises: a motor unit; and a blower unit driven by the electric motor unit. The electric motor unit includes a rotor having a magnet, a stator for generating a magnetic field for rotating the rotor, and the rotating unit. An electric blower, comprising: a frame including a child and a stator; and a ventilation path for flowing an airflow from the blower unit along the outer periphery of the frame. 2. The electric blower according to claim 1, wherein the cross-sectional area of the ventilation path is gradually enlarged to recover the pressure. 3. An impeller fixed to a rotating shaft of a rotor, an air guide disposed on an outer periphery of the impeller and having a plurality of independent diffusers, and the blower unit including the impeller and the air guide. A fan case fixed to a frame, a diffuser section of a plurality of channels connected to a diffuser section of the air guide in an air passage for flowing an airflow from the air guide along the frame, The electric blower according to claim 1, wherein the pressure is restored to a static pressure. 4. The electric blower according to claim 1, wherein a driving element for the electric motor is provided in the ventilation path.