JP2012202282A - Electric blower and electric cleaner using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric blower, in which pressure loss in blowing is reduced and a brushless motor is efficiently cooled, and whose size is reduced.SOLUTION: The electric blower is configured such that an air flow discharged from an impeller and guided by an air guide flows through an air flow path formed between an outer tube and a frame, and a plurality of air flow holes is provided on an outer circumferential face of the frame at a position where a coil end of a stator is exposed. With this configuration, the coil end of a coil that is a chief heat source of the motor is directly cooled by the air flow, and a vast increase in the pressure loss is prevented, since there is no structure that severely obstructs the stream of many air flows. Thereby, heat can be efficiently radiated while suppressing an increase in the pressure loss, and a small-sized cooling configuration with suppressed pressure loss can be achieved.

Description

  The present invention relates to an electric blower used for a household vacuum cleaner or the like.

  Conventionally, most of electric motors of electric blowers used for household vacuum cleaners use universal motors. In recent years, there has been a demand for a product with a stronger suction force and a smaller and lighter one with good usability. In view of this, an electric blower using a brushless motor has been proposed in order to improve the suction work rate by making it rotate at a higher speed, and to be small and light (see, for example, Patent Document 1).

  In this conventional example, as shown in FIG. 6, an impeller 109 attached to the tip of the rotating shaft 102 includes a rotor 101 attached to the rotating shaft 102, a stator core 104, and a coil 103. The brush 105 is rotated by a brushless motor including a frame 105 to be included and bearings 107 and 108 that rotatably connect the frame 105 and the rotating shaft 102.

  The air guide 110 disposed on the outer periphery of the impeller 109 having a plurality of blades recovers the pressure of the air blown by the rotation of the impeller 109 and causes the air guide 110 to generate an air current flowing inside the air guide 110. The stator and the rotor 101 are cooled by flowing the air flow into the brushless motor.

  The main heat generating parts of the motor are the armature / stator and commutator in the case of the universal motor, but the stator when the brushless motor is used. A proposal has been made to reduce pressure loss caused by blowing air by causing air to flow along (see, for example, Patent Document 2).

  In this conventional example, as shown in FIG. 7, an impeller 109 attached to the tip of the rotating shaft 102 includes a rotor 101 attached to the rotating shaft 102, a stator core 104, and a coil 103. The brush 105 is rotated by a brushless motor including a frame 105 to be included and bearings 107 and 108 that rotatably connect the frame 105 and the rotating shaft 102. The air guide 110 disposed on the outer periphery of the impeller 109 having a plurality of blades recovers the pressure of the air blown by the rotation of the impeller 109 and causes the air guide 110 to generate an air current flowing inside the air guide 110. The airflow is bent to a ventilation path 114 formed between the outer cylinder 113 and the frame 105.

  Then, the heat of the coil 103 and the stator core 104, which are the main places where heat is generated in the brushless motor, is radiated to the air flowing through the ventilation path 114 via the frame 105.

JP 2003-135320 A JP-A-11-336696

However, in the configuration in which air is blown into the conventional motor and cooled, it is necessary to bend the air largely from the discharge port of the air guide and guide it into the motor, resulting in a large pressure loss of the air blow. Furthermore, since the gap inside the motor is small, further pressure loss occurs to pass through this. On the other hand, in the configuration in which air flows along the outer periphery of the motor frame, the air pressure loss in the ventilation path is kept low, but the heat generated in the coil is dissipated through the core and frame, so it is enough to make it smaller Cooling is not possible. Therefore, since heat dissipation efficiency is poor, there is a problem that restrictions are imposed on downsizing.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide an electric blower that is reduced in size by reducing the pressure loss of air blowing and efficiently cooling a brushless motor.

  In order to solve the conventional problems, an electric blower of the present invention holds a rotor having a rotating shaft, a stator having a plurality of coils, and a bearing that includes the stator and supports the rotating shaft. A brushless motor configured with a frame, and having a plurality of blades, including an impeller fixed to a rotating shaft, an air guide disposed on an outer periphery of the impeller, and including the impeller and the air guide A fan case having an air inlet at the center and fixed to at least a part of the frame or the air guide, an outer cylinder connecting portion connected to the fan case, and an outer cylinder provided outside the frame; And a passage that flows along the outer periphery of the frame that is generated by the previous impeller and flows along the outer periphery of the frame. Configured, the coil end of the stator to the outer periphery of the frame has a configuration in which a plurality of ventilation holes at positions exposed.

  As a result, the coil end of the coil, which is the main heat source of the motor, is directly cooled by air, and a large amount of air flows along the outer periphery of the frame, so there is no structure that greatly impedes the flow, so the air pressure loss significantly increases. There is nothing to do. As a result, it is possible to efficiently dissipate heat while suppressing an increase in the ventilation pressure loss, so that a small cooling structure with a reduced ventilation pressure loss can be realized.

  The electric blower of the present invention can efficiently reduce the coil of the motor while suppressing the pressure loss of the air flowing on the outer periphery of the frame, and thus can be miniaturized while suppressing a decrease in the efficiency of blowing.

Partial sectional view of the electric blower according to Embodiment 1 of the present invention. 1 is a cross-sectional view taken along line AA in FIG. 1 showing an air guide and an impeller portion of the electric blower according to Embodiment 1 of the present invention. Sectional drawing of the brushless motor in Embodiment 1 of this invention Partial sectional view of the electric blower in Embodiment 2 of the present invention Sectional drawing of the brushless motor in Embodiment 2 of this invention Partial sectional view of a conventional electric blower that cools air inside the conventional motor Partial sectional view of a conventional electric blower that cools air through the outer circumference of a conventional motor

A first invention is a brushless motor configured by a rotor having a rotating shaft, a stator having a plurality of coils, and a frame holding the bearing that includes the stator and supports the rotating shaft. An impeller that has a plurality of blades and is fixed to the rotating shaft, an air guide that forms a plurality of flow paths around the impeller, and includes the impeller and the air guide. A fan case having a suction port disposed on the outer periphery thereof, and an outer cylinder provided on the outer periphery of the frame, and the air generated by the impeller and guided by the fan case and the air guide flows along the outer periphery of the frame. A passage is configured between the outer cylinder and the frame, and a plurality of side ventilation holes are provided on the outer periphery of the frame, and the side ventilation holes are formed from the vertical direction of the rotation shaft. Wherein by the coil end of the stator is disposed at a position to be exposed through the side vents, the air flow from the impeller enters from the side vents directly contacts the coil end Te. Since one of the main heat sources of the brushless motor is a stator coil, heat is transferred from the coil to the air very efficiently, so that it can be cooled efficiently.

  In the second invention, in particular, the stator of the first invention is formed by a plurality of independent concentrated winding coils, and at least one side ventilation hole is provided for the coil ends of the one opposing coil. Thus, since the coil is concentrated winding, the airflow from the impeller can be concentrated on the coil that is the heat generation source, so that the frame can be cooled more efficiently while ensuring the rigidity of the frame. Since the airflow is a swirling airflow, the airflow that hits the coil end from the side vent holes can easily escape to the outer periphery of the frame, so that an increase in pressure loss can be suppressed, so that a reduction in blowing efficiency can be suppressed.

  In the third invention, in particular, the stator of the first invention is formed by a plurality of independent concentrated winding coils, and the position of the side ventilation holes is a gap formed between the coil ends of the plurality of coils. As a result, the airflow entering the motor from the concave portion of the coil end increases, and cooling can be performed more efficiently.

  In a fourth aspect of the invention, in particular, the stator of the first aspect of the invention has a core made of a magnetic material, the core includes a tooth protruding toward the inner peripheral side, and a radial direction passing through the center of the tooth on the outer peripheral surface of the core. A groove is formed on the extension line of the core, and the groove communicates with the end faces on both sides of the core in the direction of the rotation axis. By passing, the cooling effect can be further enhanced.

  In the fifth aspect of the invention, in particular, by mounting the electric blower of any one of the first to fourth aspects of the invention on a vacuum cleaner, a vacuum cleaner that is small and lightweight and has a high suction work rate can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a partial cross-sectional view of the electric blower according to the first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a rotor, and the rotor 1 is arranged around a rotating shaft 2, and a stator having a plurality of coils 3 and a stator core 4 is arranged on the outer peripheral side of the rotor 1. The core 4 is enclosed in a frame 5 by shrinkage and the like, and the frame 5 and a bracket 6 connected to the frame 5 hold the bearing 7 and the bearing 8 and rotatably support the rotary shaft 2.

  An impeller 9 is connected to the tip of the rotating shaft 2, an air guide 10 is disposed around the impeller 9, and air discharged from the impeller 9 is gradually decelerated by independent diffusers of a plurality of channels of the air guide 10, Pressure recovery is performed.

  The fan case 11 has an air inlet for allowing air to flow into the central portion, and a resin ring 12 is disposed at the air inlet, thereby minimizing a gap with the impeller 9 and preventing air leakage. .

  An outer cylinder 13 connected to the fan case 11 is provided on the outer peripheral side of the frame 5, and a ventilation path 14 is formed between the frame 5 and the outer cylinder 13. The airflow discharged from the impeller 9 is guided to the ventilation path 14 through the air guide 10. A plurality of side ventilation holes 15 are provided at positions where the coil ends of the coils 3 are exposed on the outer peripheral surface of the frame 5.

Of the airflow passing through the ventilation path 14, a part of the airflow flowing along the frame 5 is the side ventilation hole 1
By hitting the coil end of the coil 3 through 5, the coil 3, which is one of the main heat sources of the brushless motor, is directly cooled, so that it can be efficiently cooled.

Of the airflow that has passed through the side vent holes 15 and contacted the coil end of the coil 3, some of the airflow passes through the interior of the brushless motor and cools the stator and the rotor. Most of the airflow returns to the ventilation path 14 again because the gap in the brushless motor is smaller than that of the ventilation path 14.
Thus, since the airflow which flows through the ventilation path 14 is not blocked | interrupted largely, the big increase in pressure loss can be suppressed.

  FIG. 2 is a cross-sectional view taken along line AA in FIG. 1 showing an air guide and an impeller portion of the electric blower according to Embodiment 1 of the present invention. In FIG. 2, the airflow discharged toward the outer periphery from the impeller 9 having a plurality of blades attached to the rotating shaft 2 is gradually recovered by the air guide 10, and then the airflow inside the outer cylinder 13. It is sent to the road 14 as a swirling airflow. Therefore, the airflow is introduced into the side ventilation holes 15 of the frame 5 by the swirling airflow generated in the ventilation path 14.

FIG. 3 is a cross-sectional view of the brushless motor according to Embodiment 1 of the present invention.
In FIG. 3, the side ventilation holes 15 provided in the frame 5 are aligned with the positions of the gaps formed between the coil ends of the plurality of coils 3 that are concentrated. The swirling airflow enters the brushless motor through the side ventilation holes 15, hits the coil end and again goes out of the brushless motor, passes between the coil end and the frame 5, and further from the gap between the coil ends to the inner periphery. Some of them go out of the brushless motor again through the side.

  In order to facilitate the introduction of the swirl airflow from the side vent hole 15 to the inner peripheral side without obstructing the swirl airflow, the edge 16 on the upstream side of the swirl airflow of the side vent hole 15 has a shape of a slope facing the outer peripheral side. Since the whirling airflow along the shape of the frame 5 follows the shape of the inclined surface, it becomes easier to go to the inner peripheral side. Thereby, the airflow which contacts the coil 3 increases and cooling performance improves.

  Further, since the edge 17 of the side ventilation hole 15 on the downstream side of the swirling airflow is bent so as to protrude toward the outer peripheral side, it becomes easy to introduce between the frame 5 and the coil 3 and inside thereof. Thereby, the airflow which contacts the coil 3 increases further, and cooling performance improves.

  In FIG. 1, pressure loss can be reduced by making the inner corner of the fan case 11 facing the outer peripheral side of the air guide 10 a curved surface so that the airflow passing through the air guide 10 is gradually changed. .

(Embodiment 2)
FIG. 4: shows the partially broken front view of the electric blower in the 2nd Embodiment of this invention.
In FIG. 4, reference numeral 1 denotes a rotor, and the rotor 1 is arranged around a rotation shaft 2. A stator having a coil 3 and a stator core 4 is arranged on the outer peripheral side of the rotor 1. 4 is fixed to the frame 5, and the frame 5 and the bracket 6 connected to the frame 5 hold the bearing 7 and the bearing 8 and rotatably support the rotating shaft 2.

An impeller 9 is connected to the tip of the rotating shaft 2, an air guide 10 is disposed around the impeller 9, and air discharged from the impeller 9 is gradually decelerated by independent diffusers of a plurality of channels of the air guide 10, Pressure recovery is performed.
The fan case 11 has an air inlet for allowing air to flow into the central portion, and a resin ring 12 is disposed at the air inlet, thereby minimizing a gap with the impeller 9 and preventing air leakage. .

  An outer cylinder 13 connected to the fan case 11 is provided on the outer peripheral side of the frame 5, and a sound absorbing material 18 is connected to the inner side of the outer cylinder 13, and the sound absorbing material 18 usually has sufficient rigidity to pass an air flow. Have. A ventilation path 14 is formed between the outer cylinder 13 and the sound absorbing material 18 and the frame 5.

  The airflow discharged from the impeller 9 is guided to the ventilation path 14 through the air guide 10. A plurality of side ventilation holes 15 are provided at positions where the coil ends of the coils 3 are exposed on the outer peripheral surface of the frame 5. Of the airflow passing through the ventilation path 14, a part of the airflow flowing along the frame 5 passes through the side ventilation holes 15 and hits the coil end of the coil 3, thereby directly cooling the coil 3 that is a main heat source of the brushless motor. Therefore, it becomes possible to cool efficiently.

  Of the airflow that has passed through the side vent holes 15 and contacted the coil end of the coil 3, some of the airflow passes through the interior of the brushless motor and cools the stator and the rotor. Most of the airflow returns to the ventilation path 14 again because the gap in the brushless motor is smaller than that of the ventilation path 14.

  In addition, the ventilation path 14 has a function of increasing the ratio of the air flow along the frame 5 because the sound absorbing material 18 ensures that the air flow sufficiently flows and restricts the air flow in a direction approaching the frame 5. is doing.

  Thus, since the airflow which flows through the ventilation path 14 is not blocked | interrupted largely, the big increase in pressure loss can be suppressed. The airflow discharged from the impeller 9 is discharged as a swirling airflow through the air guide 10 to the ventilation path 14 as in FIG. 2 of the first embodiment. Therefore, the airflow is introduced into the side ventilation holes 15 of the frame 5 by the swirling airflow.

FIG. 5 is a cross-sectional view of the brushless motor according to the second embodiment of the present invention.
In FIG. 5, the side ventilation holes 15 provided in the frame 5 are arranged in accordance with the position of the peak of the coil end of the coil 3 that is concentrated.

  The stator core 4 has teeth 20 protruding toward the inner peripheral side, and the coil 3 is wound around the teeth 20.

  A groove 19 is provided on the outer circumferential surface of the stator core 4 on a radially extending line passing through the center of the teeth 20, and the groove 19 is configured to communicate with both end faces of the stator core 4 in the rotation axis direction. Therefore, a part of the airflow that has entered the brushless motor from the side ventilation holes 15 passes through the groove 19 on the outer periphery of the core, so that the cooling effect can be further enhanced.

  Most of the swirling airflow that enters from the side vent holes 15 flows again to the outer periphery of the frame 5 at the coil end crest, so that the airflow is not greatly hindered. Thereby, it is possible to increase the cooling efficiency while suppressing an increase in pressure loss.

  The groove 19 has a V-groove shape in the cylindrical stator core 4. However, if the size and shape do not cause a problem as the magnetic circuit of the stator core 4, the groove 19 is formed between the frame 5 and the both sides of the stator core 4. It goes without saying that the same effect can be obtained with any shape as long as it forms a passage communicating with the end face.

As described above, the electric blower according to the present invention can directly cool the coil end while suppressing the pressure loss of the air flowing on the outer periphery of the frame, and thus can be reduced in size while suppressing the decrease in the efficiency of the blowing. Therefore, a small and light electric blower with high air blowing efficiency can be realized. In addition, by using this electric blower, it is possible to realize a vacuum cleaner that is small and light and has a high suction work efficiency and is easy to use.

DESCRIPTION OF SYMBOLS 1 Rotor 2 Rotating shaft 3 Coil 4 Stator core 5 Frame 6 Bracket 7 Bearing 8 Bearing 9 Impeller 10 Air guide 11 Fan case 12 Resin ring 13 Outer cylinder 14 Ventilation path 15 Side ventilation hole 16 Edge 17 Edge 18 Sound absorbing material 19 Groove 20 Teeth 101 Rotor 102 Rotating shaft 103 Coil 104 Stator core 105 Frame 106 Bracket 107 Bearing 108 Bearing 109 Impeller 110 Air guide 111 Fan case 112 Resin ring 113 Outer cylinder 114 Ventilation path

Claims (5)

A rotor having a rotation axis;
A stator having a plurality of coils;
A brushless motor that includes a frame that includes a stator and holds a bearing that supports the rotating shaft;
An impeller having a plurality of blades and fixed to the rotating shaft;
An air guide that forms a plurality of flow paths around the impeller; and
A fan case containing the impeller and the air guide and having an air inlet disposed in the center;
An outer cylinder provided on the outer periphery of the frame,
A path for flowing the air generated by the impeller and guided by the fan case and the air guide along the outer periphery of the frame is configured between the outer cylinder and the frame.
A plurality of side ventilation holes are provided on the outer periphery of the frame, and the side ventilation holes are arranged at positions where the coil ends of the stator are exposed through the side ventilation holes when viewed from the vertical direction of the rotating shaft. Blower. The stator is formed of a plurality of independent concentrated winding coils,
2. The electric blower according to claim 1, wherein at least one side vent hole is provided for a coil end of one of the opposing coils. The stator is formed of a plurality of independent concentrated winding coils,
The electric blower according to claim 1, wherein the position of the side ventilation hole is configured to match the position of a gap formed between coil ends of the plurality of coils. The stator has a core made of a magnetic material,
The core includes teeth protruding to the inner peripheral side,
On the outer peripheral surface of the core, a groove is provided on a radially extending line passing through the center of the tooth,
The electric blower according to claim 1, wherein the groove is configured to communicate with end faces on both sides of the core in a rotation axis direction. The vacuum cleaner carrying the electric blower of any one of Claims 1-4.