JP2896058B2 - Outer rotor type brushless DC motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer rotor type brushless DC motor used for home electric appliances.

[0002]

2. Description of the Related Art Today, many electric motors are used in home electric appliances. For example, taking a small air conditioner as an example, a motor having an output of about several W to several tens of W is used as a motor for the indoor unit fan and the outdoor unit fan, and a brushless DC motor has recently been used to improve operation efficiency. Is being used. And such a brushless D
As a C motor, for example, as shown in Japanese Utility Model Publication No. 63-16297, a rotor provided with a permanent magnet as a magnetic material rotates around a stator formed by winding coils around a plurality of teeth. There are an outer rotor type configured and an inner rotor type having a structure in which a rotor is disposed inside a stator as disclosed in Japanese Utility Model Publication No. 63-34449.

[0003] In the case of small air conditioners, it has become a major problem to reduce the size of a fan motor in accordance with the size of the unit. Here, the relationship between the motor torque (T) and the stator core is represented by T = L × D * 2. Note that D is the inside diameter of the air gap, and L is the thickness of a plurality of teeth.

Accordingly, in order to increase the torque and the output of the motor, the inner diameter (D) of the air gap may be increased, and a comparison is made between an inner rotor type and an outer rotor type which generate the same torque and output. In addition, the outer rotor type in which the inner diameter (D) of the air gap is large can reduce the thickness of the plurality of teeth, so that the thickness can be reduced. Further, the outer rotor type is capable of high-speed winding work of windings as described later, and the number of assembling steps can be reduced.

On the other hand, in such an outer rotor type brushless DC motor, for example, Japanese Unexamined Patent Publication No.
In order to suppress vibration and noise as disclosed in Japanese Patent Publication No. 55-55, a stator is molded with a thermosetting resin which is a thermosetting synthetic resin. Further, a housing portion for housing the bearing is formed so as to protrude the motor case outward, and this protruding portion serves as a mounting portion so that the motor can be assembled in the product body.

[0006]

However, in such a conventional outer rotor type brushless DC motor, once molded, it takes a great deal of time to remove the mold. Defective products and motors that have become unusable due to product life are treated by means such as burying them in the mountain without collecting the stator, and have had problems in terms of environmental issues and resource recycling. In addition, since the molding operation requires a long molding time, there is a problem that, when mass-producing, the number of machinery and equipment increases, and rapid mass production cannot be coped with.

Accordingly, the present invention has been made to solve such a problem, and provides an outer rotor type brushless DC motor which can suppress vibration and noise without molding and can be mass-produced in a small size. It is intended to do so.

[0008]

SUMMARY OF THE INVENTION The present invention provides an outer rotor type brushless DC motor in which a rotor having a magnetic material mounted thereon rotates around a stator having a plurality of teeth wound with coils. , A first housing having a mounting recess formed by double drawing of a steel plate, and a cylindrical support portion extending inward from an edge of the mounting recess is formed by double drawing. A second housing that has a mounting recess formed by drawing a steel plate and that is combined with the first housing to form a predetermined space; and a cylindrical shape formed by drawing a steel plate, and has one end. A stator support cylinder attached to the outside of the cylindrical support portion of the first housing, attached to the outside of an attachment recess formed by double drawing, and attached to the outer periphery of the other end; , A magnetic material supporting body formed along the inner side of the second housing by processing of a conductive steel plate and positioned in the predetermined space and holding the magnetic material so as to surround an outer periphery of the stator; The first housing-side bearing and the second housing-side bearing mounted in the mounting recesses of the housing and the second housing, respectively, are rotatably inserted into and supported by the two bearings, and the magnetic body support is mounted and fixed. And a shaft.

In the present invention, the inner diameter of the cylindrical support portion of the first housing is larger than the inner diameter of the mounting recess.

[0010]

According to the first aspect of the present invention, the first housing in which the mounting recess for mounting the bearing is formed by double drawing of the steel plate is connected to the second housing in which the mounting recess for mounting the bearing is formed by drawing of the steel plate. Thus, a predetermined space can be formed. In addition, one end of the stator support cylinder formed into a cylindrical shape by drawing of a steel plate is connected to a cylindrical support formed by double drawing inward from the edge of the mounting recess of the first housing. By attaching the stator support cylinder to the outside, the stator support cylinder can be fixed to the first housing while being positioned in a predetermined space. Furthermore, the stator can be attached to the stator support cylinder by fitting the stator to the outer periphery of the other end of the stator support cylinder.

Further, a magnetic support which is formed along the inner side of the second housing by bending the magnetic steel plate and holds the magnetic body so as to surround the outer periphery of the stator,
It can be attached and fixed to a shaft rotatably inserted and supported by both bearings of the first and second housings.

According to the second aspect of the present invention, when the inner diameter of the support portion of the first housing is larger than the inner diameter of the mounting recess in advance, when the stator support cylinder is press-fitted into the support portion and mounted, the first inner portion is formed. The influence of the dimensional change on the inner diameter of the housing can be prevented, and the assembling operation can be smoothly performed.

[0013]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an outer rotor type brushless DC motor according to an embodiment of the present invention. In the figure, reference numeral 1 denotes an outer rotor type brushless DC motor main body (hereinafter referred to as a motor main body);
Denotes a first housing and a second housing which form a housing of the motor body 1.

Here, the first housing 2 is formed by drawing a steel plate, and firstly, a cylindrical support portion 4A projecting inward at a central portion by a predetermined length is formed by double drawing.
The mounting recess 4 </ b> B is integrally formed so as to protrude outward from the heavy drawing portion.

The second housing 3 is formed by drawing a steel plate into a cylindrical shape with a bottom, and has a mounting recess 4B on the bottom surface.
A mounting recess 5 protruding outward corresponding to the first housing 2 is integrally formed with the first housing 2. And
As described later, a first bearing 6 (bearing portion) and a second bearing 6a (bearing portion), which are bearings for inserting and supporting a shaft, are fitted and supported in the recesses inside the mounting recesses 4B and 5 as described later. Like that.

In FIG. 1, reference numeral 7 denotes a stator, and reference numeral 8 denotes a magnetic support which is a rotor on which a permanent magnet 9 is mounted. Here, the stator 7 is formed by stacking a plurality of electromagnetic steel sheets punched into a shape having a plurality of teeth as shown in FIG.
Is formed by winding.

The stator core 10 has a plurality of open grooves 10a around which the coil L is wound as shown in FIG. High-speed winding work of the winding is possible as compared with the winding work of No. Also, this stator 7
The skew is applied and the layers are stacked, whereby the cogging torque is reduced, and the vibration and noise during motor operation can be reduced.

The stator 7 is formed by drawing a steel plate into a cylindrical shape, and has one end portion of the first housing 2.
The press-fit is fixed to the outer periphery of the other end of the stator support tube 12 which is fitted and fixed to the outside of the support portion 4A formed by the double drawn portion. At the other end of the stator support cylinder 12, a stepped portion 12a for positioning the stator 7 to be press-fitted and fixed is formed by drawing.

Then, the positioning step 12a for positioning is formed in the stator supporting cylinder 12 as described above, and the stator 7 is fixed to the mounting position by pressing the stator 7 against the step 12a at the time of press-fitting. I can do it. Further, by fixing the stator 7 at a fixed position in this way, the deflection of the stator 7 can be prevented, so that the generation of vibration and noise can be prevented, and the magnetic material support specified in the Electrical Appliance and Material Control Law. The space distance from the body 8 can be secured.

The inner diameter of the stepped portion 12a is larger than the outer diameter of the first bearing 6 so that the first bearing 6 can be assembled after the stator support cylinder 12 is fitted and fixed to the first housing 2. Is also formed to be large. Further, the stator support tube 12 is connected to the first housing 2.
When the fitting is fixed to the outside of the narrowed portion, the narrowed portion hardly bends to the mounting recess 4B side since the narrowed portion is formed double, so that the first bearing 6 can be incorporated without being damaged. Has become.

On the other hand, the magnetic support 8 is formed by bending a magnetic steel plate along the second housing 3 and has an annular yoke 8a on the outer periphery for mounting and fixing the permanent magnet 9 on the inner periphery. A yoke side wall 8b bent at a right angle from the annular yoke 8a toward a shaft 13 to be described later, and a cylinder formed to extend from the yoke side wall 8b to a space between the first and second bearings 6, 6a. And a shaft-shaped mounting portion 8c.

By attaching and fixing the permanent magnet 9 to the inner periphery of the annular yoke 8a as described above, the centrifugal force applied to the permanent magnet 9 when the magnetic support 8 rotates is reduced.
, Whereby the permanent magnet 9 can be prevented from cracking and scattering.

Further, the magnetic support 8 is connected to the second housing 3.
, The thickness in the width direction of the motor body 1 can be reduced, and the shaft mounting portion 8c
Is extended between the two bearings 6 and 6a, thereby utilizing the space between the bearings 6 and 6a to utilize the space between the bearings 6 and 6a.
The thickness in the height direction can be reduced, so that the size of the motor body 1 can be reduced.

The shaft 13 is rotatably inserted into the first and second bearings 6 and 6a and supported in a double-supporting manner, and is press-fitted into the shaft mounting portion 8c to mount and fix the magnetic body support 8. It was done. Further, a knurl 13a is formed on the shaft 13, and the knurl 13a prevents the magnetic substance support 8 from coming off the shaft 13. In FIG. 1, reference numeral 14 denotes a bearing receiver, and reference numeral 15 denotes a preload spring for pressing the first bearing 6 mounted on the mounting recess 4B of the first housing 2 against the bearing receiver 14.

Next, the assembling operation of the outer rotor type brushless DC motor configured as described above will be described.

In order to assemble the motor body 1, first, the stator 7 is pressed into the outer periphery of the stator support tube 12 until it comes into contact with the stepped portion 12a, and then fixed. To fix the stator 7 at a fixed position.

Next, after the preload spring 15 is inserted into the mounting recess 4B of the first housing 2, the first bearing 6 is passed through the stator support tube 12 to allow the mounting recess 4B of the first housing 2 to pass.
B fits. Thereafter, the shaft mounting portion 8c is
Shaft 1 which is press-fitted into and integrated with the magnetic support 8
3 is inserted through the first bearing 6.

Next, after inserting the second bearing 6 a from the other end of the shaft 13, the second bearing 6 a is moved along the shaft 13 and fitted into the mounting recess 5 of the second housing 3. Thus, the shaft 13 is rotatably inserted and supported by the two bearings 6 and 6a. Finally, after attaching the shaft 13 in this way,
The second housing 3 is mounted, and the second bearing 6a fitted in the mounting recess 5 of the second housing 3 is fixed.

The motor body 1 assembled in this manner can be downsized because the first housing 2 and the second housing 3 are formed by drawing a steel plate. Further, the stator 7 is press-fitted and fixed to the stator support tube 12, and the stator support tube 12 is
The stator 7 can be fixed without being molded by being fitted to the outside of the support portion 4A formed by the heavy drawing portion.
Further, the magnetic body support 8 is formed by bending a magnetic steel plate along the second housing 3 so that the motor main body 1 can be further thinned. The motor main body 1 can be easily mounted and fixed in the product main body using the mounting recesses 4B and 5 formed on the first housing 2 and the second housing 3 and protruding outward. At this time, it is also possible to reduce the vibration and noise when the motor is driven by inserting a vibration isolating rubber around the mounting recesses 4B and 5 and mounting the rubber.

The annular yoke 8 of the magnetic support 8
Since a must have a sufficient thickness as a magnetic path so that magnetic saturation does not occur, the magnetic steel sheet forming the magnetic body support 8 has a thickness such that magnetic saturation does not occur in the annular yoke 8a. It is assumed.

Next, a description will be given of a second invention of the present invention configured to facilitate press-fitting of the first bearing into the first housing. An example is shown in FIG. Note that the same reference numerals in FIG. 1 as those in FIG. 1 indicate the same or corresponding parts.

That is, the inner diameter a of the support portion 4A is slightly larger than the inner diameter b of the mounting recess 4B in which the first bearing 6 is accommodated, and the first housing 2B is drawn.

In this way, when the first bearing 6 is press-fitted into the mounting recess 4B, the inlet is wide, so that the press-fitting operation can be performed smoothly, and the first bearing 6 inserted when the inner diameter is the same. Thus, there is no need to worry about deforming the support 4A.

On the other hand, in the above description, the mounting recess for fitting the first bearing and the support portion for press-fitting and fixing the stator support tube 12 have been described as being formed integrally with the first housing. The present invention is not limited to this, and the bearing mounting member may be formed separately, and the mounting member may be fixed to the first housing by welding or the like.

Next, an embodiment in such a case will be described with reference to FIG.

Referring to FIG. 2, reference numeral 2C denotes a first steel plate formed by drawing a steel plate and integrally forming a cylindrical fitting portion 2a protruding inward at the center, that is, a portion corresponding to the support portion 4A.
Housing. Reference numeral 16 denotes a bearing mounting body formed by drawing a steel plate into a bottomed cylindrical shape, fitting the opening-side end 16b inside the fitting portion 2a of the first housing 2C, and mounting the same by spot welding or the like. This corresponds to the mounting recess 4B of the first housing 2 described above. And
Also in this case, the end 16 on the opening side of the bearing
The inner diameter of b is larger than the inner diameter of the mounting recess 16c into which the first bearing 6a is press-fitted, thereby facilitating the insertion of the first bearing 6a.

12A is formed by drawing a steel plate into a cylindrical shape, and is formed outside the overlapping portion between the fitting portion 2a of the first housing 2C and the opening end 16b of the bearing mounting body 16 fitted inside the fitting portion 2a. And a stator support cylinder in which one end is fitted and attached by spot welding or the like, and the stator 7 is press-fitted and fixed to the outer periphery of the other end.

As described above, the first housing 2C having the stator support cylinder 12A, the bearing mounting body 16, and the fitting portion 2a for fitting the stator support cylinder 12A to the outside and the bearing mounting body 16 to the inside, respectively. By joining the two components, the bearing mounting body 16 can be mounted on the first housing 2C, and the stator support tube 12 can be mounted.
A can be attached to the first housing 2C, and the stator 7 can be fixed without being molded, and vibration of the stator 7 can be prevented.

In this embodiment, as in the first and second embodiments, the mounting recess 4B and the support portion 4A are provided in the first housing.
Are not integrally formed as one part, but the bearing mounting body 16
And the first housing 2C, and the two parts are assembled by press-fitting or bonding, so that there is an advantage that drawing is easy.

The portion of the stator support cylinder 12A, into which the stator 7 is press-fitted and fixed, is formed smaller in diameter than the coupling portion fitted to the fitting portion 2a of the first housing 2C. By forming the portion where the stator 7 is press-fitted and fixed smaller than the coupling portion in this way, a stepped portion 12a for positioning can be provided at the boundary between these two portions, and the stator 7 can be fixed. Position.

[0042]

As described above, according to the present invention, the first housing, the second housing, the stator support cylinder, the magnetic support and the like are formed by drawing, and these components are combined and fixed to form a motor. By doing so, it is possible to easily manufacture and mass-produce a motor of a type in which an attachment portion advantageous for attachment to the product main body projects outside the housing. Also,
Vibration and noise can be suppressed without molding by fixing the stator to the stator support cylinder by press-fitting and fixing the stator support cylinder to the first housing. As a result, it is possible to mass-produce a small-sized outer rotor type brushless DC motor which is excellent in workability by manufacturing mainly by press working, and is inexpensive and high quality.

[0043]

[Brief description of the drawings]

FIG. 1 is a side sectional view of an outer rotor type brushless DC motor according to an embodiment of the present invention.

FIG. 2 is a front view of a stator core of the motor.

FIG. 3 is a side sectional view of an outer rotor type brushless DC motor according to an embodiment of the present invention of claim 2;

FIG. 4 is a side sectional view of an outer rotor type brushless DC motor according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor main body 2, 2A, 2B 1st housing 3 2nd housing 6, 6a Bearing 7 Stator 8 Magnetic body support 12, 12A Stator support cylinder 13 Shaft

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02K 29/00 H02K 5/24 H02K 15/14 H02K 21/22

Claims (2)

(57) [Claims] 1. An outer rotor type brushless DC motor in which a rotor on which a magnetic material is mounted rotates around an outer periphery of a stator formed by winding a coil around a plurality of teeth. A first housing having a mounting recess formed by a double-drawing process and a cylindrical support portion extending inward from an edge of the mounting recess; and a drawing process of a steel plate. Mounting recess, wherein the first
A second housing coupled to the housing to form a predetermined space; and a steel plate drawn into a cylindrical shape by drawing, and one end portion of the first housing is formed of the first housing.
A stator support cylinder attached to the outside of the cylindrical support portion of the housing and having the stator attached to the outer periphery of the other end; and a magnetic steel plate formed along the inside of the second housing by machining a magnetic steel plate. A magnetic body support that is located in a predetermined space and holds the magnetic body so as to surround the outer periphery of the stator; and a bearing on the first housing side that is mounted in a mounting recess of the first housing and the second housing, respectively. An outer rotor type brushless DC motor, comprising: a bearing on the second housing side; and a shaft rotatably inserted into and supported by the two bearings and having the magnetic body support attached and fixed thereto. 2. An outer rotor type brushless DC according to claim 1, wherein an inner diameter of said cylindrical support portion of said first housing is larger than an inner diameter of said mounting recess.
motor.