JP2003274596A - Motor-driven blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor-driven blower capable of reducing electromagnetic noises at driving caused by the displacement of magnetic centers of a magnet and a stator core due to variations of errors in forming an impeller and assembling in a rotor yoke insertion process. <P>SOLUTION: The blower comprises a bushing for supporting a casing and a stator core, a multiple blade blowing fan firmly fixed to a rotating shaft, a rotor yoke with a magnet inserted into the multiple blade blowing fan and a bearing freely rotatably supporting the multiple blade blowing fan. By allowing a movable sleeve on the inner surface of the bushing to move in the direction of the rotating shaft, the height position of the magnet can be varied, which lead to coincidence of the magnetic centers. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric blower equipped with a multi-blade blower fan and suitable for noise reduction.

[0002]

2. Description of the Related Art In a conventional electric blower, a bushing is fixed to the center of a lower case, a stator core is mounted on the outer peripheral surface of the bushing, and a rotating shaft is rotatably supported by a bearing on the inner peripheral surface of the bushing. There is. One end (upper end) of the rotary shaft is fixed by a boss portion of the multi-blade blower fan, and a rotor holder portion protruding in the axial direction around the boss portion is formed.
A rotor yoke with a magnet is inserted and fixed to the inner peripheral surface thereof. The magnet is arranged so as to face the inner stator core.

Regarding the height position where assembly accuracy is required to match the magnetic centers of the magnet and the stator core, as shown in Japanese Patent Laid-Open No. 11-275797, a spindle motor of a fixed shaft type will be taken as an example below. Has been made.

FIG. 4 shows an example of a fixed shaft type spindle motor, in which a fixed base board is formed in a shallow dish shape, and a fixed shaft is integrally erected at a central portion of the base board, and an outer circumference of the fixed shaft is provided. A rotor hub is rotatably supported by a pair of bearings. An annular wall is provided concentrically with the fixed shaft on the base substrate, and the stator core is externally fitted and fixed to the annular wall, and faces the outer peripheral surface of the stator core with a slight gap, An annular magnet is attached to the rotor hub.

The outer ring and the inner ring of both bearings are fixed to the inner peripheral surface of the rotor hub and the outer peripheral surface of the fixed shaft by using an adhesive agent. In order to control the bonding position of each of them with high precision, It has been devised. That is, the base substrate is provided with a plurality of through holes that are axially opposed to the end surface of the outer ring or the inner ring of the bearing and that allow pins to be inserted from the outside to contact the end surface at equal intervals in the circumferential direction. . This makes it possible to mount the bearings with respect to the base substrate with extremely high accuracy while preloading the bearings.

[0006]

In recent years, severe noise reduction has been required for the noise of the blower, and it is necessary to reduce the noise of the motor as well. It is a well known fact that the electromagnetic noise generated during the rotation of the motor becomes large when the magnetic centers of the magnet and the stator core are deviated.

However, even if the bearing structure of the spindle motor is adopted in the blower in order to make the magnetic centers coincide with each other, for example, as disclosed in Japanese Patent Laid-Open No. 11-275797, due to the molding error of the impeller and the assembly error of the rotor yoke insertion process. ,
There is a problem in that it is difficult to match the magnetic centers of the magnet and the stator core with each other, and a large amount of electromagnetic noise is generated. Further, since it is impossible to correct the deviation of the magnetic center after assembling, there is a problem that mass productivity is poor.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an electric blower suitable for noise reduction and easy to adjust.

[0009]

To achieve the above object, a first aspect of the present invention is directed to a bushing for supporting a casing and a stator core, a multi-blade blower fan fixed to a rotary shaft, and a magnet inserted in the multi-blade blower fan. A movable sleeve is provided on the inner surface of the bushing in an electric blower including a rotor yoke with a rotor and a bearing that rotatably supports the multi-blade blower fan. As a result, the movable sleeve moves in the direction of the rotation axis, and the height position of the magnet can be adjusted.By matching the magnetic centers of the magnet and the stator core, electromagnetic noise is reduced, and the noise level of the blower as a whole is reduced. It becomes possible to reduce.

A second aspect of the present invention is characterized in that a fixing means for fixing the movable sleeve of the first aspect to an arbitrary position is provided. As a result, unlike the conventional case, since the correction can be easily performed even after the electric blower is assembled, the mass productivity can be improved. Regarding the fixing means, for example, by constructing the bushing and the movable sleeve with a screw structure, not only adjustment is easy, but also correction can be made after assembly because it can be corrected after electromagnetic noise inspection, further improving mass productivity. it can. As for the fixing means, if it has the same function, other than the screw structure can be used.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional plan view showing an embodiment of an electric blower according to the present invention, and FIG. 2 is a vertical sectional view thereof. A multi-blade blower fan 3 having a plurality of blades 9 in a spiral upper casing 1 and a lower casing 2 as shown in FIGS. 1 and 2, and a multi-blade blower fan 3
A motor main body for rotationally driving the motor and a circuit board 49 for rotationally driving the motor are incorporated.

In FIG. 2, the center portion of the base plate 15 of the multi-blade blower fan 3 is formed with a rotor holder portion 17 protruding in the axial direction, and the rotor yoke 35 of the motor is press-fitted and fixed to the inner peripheral surface of the protruding portion. ing. An annular magnet 37 is attached to the inner peripheral surface of the rotor yoke 35, and a stator core 41 is provided inside the rotor yoke 35 so as to face the magnet 37.

The stator core 41 includes the stator core 41 mounted on the outer peripheral surface of the bushing 43, and the stator core 4
1 has a coil 47 wound via an insulator 45. A movable sleeve 44 is arranged on the inner peripheral surface of the bushing 43, and the inner surface of the bushing 43 and the outer surface of the movable sleeve 44 are fixed by a screw structure, and the height can be changed by rotating the movable sleeve 44 after assembly. it can.

The rotary shaft 33 is rotatably supported by the movable sleeve 44 via a pair of bearings 39.
3 has one end (upper end) at the boss portion 19 of the multi-blade blower fan 3.
It is fixed by insert molding. Although the rotary shaft 33 is insert-molded in the multi-blade blower fan 3 in FIG. 2, the rotary shaft 33 is fixed to the rotor yoke 35 by caulking and the multi-blade blower fan 3 is press-fitted into the rotor yoke 35. Also good. The bearing 39 is a rolling bearing as an example, but one or a plurality of slide bearings may be used.

Further, in the conventional bearing structure, as shown in FIG. 3, the bushing 43 has a stator core 41 mounted on the outer peripheral surface and a pair of bearings on the inner peripheral surface, and the height cannot be adjusted. is there. In the above structure, the multi-blade blower fan 3 fixed to the rotor yoke 35 is energized by the motor to rotate the air, so that the air flowing in through the intake port 23 passes through the inter-blade gap 11 and the wall plates 27 of the upper and lower casings 1 and 2. After passing through the air outflow passage 29 formed in the gap between the multi-blade blower fan 3 and the air, the air is blown out from the exhaust port 25.

[0016]

The present invention has the following effects due to the above configuration. In the first aspect, the movable sleeve on the inner surface of the bushing moves in the direction of the rotation axis, so that the magnetic centers of the magnet and the stator core can be aligned. This makes it possible to provide a low-noise electric blower with reduced electromagnetic noise.

According to the second aspect of the present invention, the movable sleeve on the inner surface of the bushing is provided with the fixing means capable of fixing the movable sleeve at an arbitrary position, so that it can be easily corrected even after the electric blower is assembled.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention and a conventional structure.

FIG. 2 is a vertical sectional view showing an embodiment of the present invention.

FIG. 3 is a vertical sectional view showing a conventional structure.

FIG. 4 is a vertical cross-sectional view showing a conventional shaft-fixed type spindle motor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Upper casing, 2 ... Lower casing, 3 ... Multiblade ventilation fan, 7 ... Upper support plate, 9 ... Blade, 9a ... Blade inner end surface, 9b ... Blade outer end surface, 11 ... Blade gap, 13 ... Auxiliary ring, 15 ... Base plate, 17
... Rotor holder part, 19 ... Boss part, 23 ... Intake port, 25
…exhaust port. 27 ... Wall plate, 29 ... Air flow path, 31 ... Tongue part,
33 ... Rotating shaft, 35 ... Rotor yoke, 37 ... Magnet, 39 ... Bearing, 41 ... Stator core, 43 ... Bushing, 44 ... Movable sleeve, 45 ... Insulator, 47
… Coil, 49… Circuit board, 51… Base board, 53…
Fixed shaft, 55, 56 ... Bearing, 55a, 56a ... Bearing outer ring, 55b, 56b ... Bearing inner ring, 57 ... Annular wall, 5
9 ... Annular protrusion, 61 ... Rotor hub, 63 ... Through hole, 65
…cap

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Claims (2)

[Claims] 1. A bushing for supporting a casing and a stator core, a multi-blade fan fixed to a rotary shaft, a rotor yoke with a magnet inserted in the multi-blade fan, and a bearing for rotatably supporting the multi-blade fan. In an electric blower configured, an electric blower is provided on the inner surface of the bushing, the movable sleeve being movable in the rotation axis direction. 2. The electric blower according to claim 1, wherein the electric blower is provided with fixing means capable of fixing the movable sleeve at an arbitrary position.