JP3262418B2 - Brushless motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor, and more particularly to an improved brushless motor employing a sleeve bearing.

[0002]

2. Description of the Related Art As is well known, a DC motor generally includes a stationary member to which a DC current is supplied and a rotating member having a magnet. The rotating member is rotatable with respect to the stationary member. Supported. In a DC motor having such a configuration, generally, a ball bearing is interposed between a rotating member and a stationary member, and a laminated stator core is provided on the stationary member side, and a stator coil is wound around the stator core. The rotating member is provided with a magnet facing the stator core on the rotating member side, and the rotating member rotates by an electromagnetic interaction between a current magnetic field generated when a DC current is supplied to the stator coil and the rotor magnet.

However, recently, for example, in a brushless motor used in a radiating fan device of an electronic device or the like, a cylindrical sleeve bearing is employed instead of an expensive ball bearing, and the sleeve bearing is stationary. The cylindrical part of the housing, which is the supporting part on the member side, is formed of synthetic resin,
A simple, lightweight and inexpensive device is provided. However, technical problems described below have been pointed out for the brushless motor having such a structure.

[0004]

That is, in the brushless motor having the above-described structure, an annular stator core is fitted and fixed to the cylindrical portion of the housing. In this case, the cylindrical portion is formed of synthetic resin. In this case, when the stator core is fitted and fixed to the tubular portion, the tubular portion is deformed, affecting the sleeve bearing, and hindering smooth rotation of the rotating member.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a brushless motor which can ensure smooth rotation.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a brushless motor having a housing on which a stator is mounted and a rotor rotatably supported on the housing via a sleeve bearing. The stator includes a stator core, a stator coil, an insulator to which the core and the coil are mounted, and a hollow cylindrical metal bush integrally formed with the insulator, and the rotor includes the sleeve bearing. And a magnet facing the stator core, the housing surrounds an outer periphery of the sleeve bearing, the stator core is fitted to the outer periphery, and an opening edge at an upper end is formed of the metal bush. And a metal receiving member that is press-fitted into the housing.

[0007]

According to the brushless motor having the above construction, the stator comprises a stator core, a stator coil, an insulator to which the core and the coil are mounted, and a hollow cylindrical metal bush integrally formed with the insulator. The rotor has a shaft portion inserted into the sleeve bearing, and a magnet facing the stator core. An opening edge at an upper end has a metal receiving member pressed into the metal bush. The stator is supported by press-fit portions of a metal bush and a metal receiving member, and since these press-fit target members are all made of metal, almost no deformation occurs during press-fit. The stator can be reliably supported.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of a brushless motor according to the present invention. This embodiment shows a case where the present invention is applied to a fan device.
The motor shown in FIG.
And a housing 11 on which the housing 11 is mounted.
And a rotor 13 rotatably supported via a sleeve bearing 12.

The stator 10 includes a stator core 14 in which annular magnetic plates are laminated, a stator coil 15 wound around the stator core 14, and an insulator 1 on which the stator core 14 and the stator coil 15 are mounted.
6. The insulator 16 is integrally formed of a synthetic resin. An annular wall 18 having an inverted L-shaped cross section is formed on an inner peripheral upper portion of the base portion 17, and a hollow cylindrical shape is formed on a lower surface of the annular wall 18. Metal bush 19
It is integrally molded by insert molding.

The metal bush 19 has a substantially L-shaped cross section, a flange 19a is provided at the upper end, a part of which protrudes below the annular wall 18, and the outer peripheral surface of the bush 19 and the annular wall 18 are formed. An annular concave portion 20 having an open lower end is formed between the inner peripheral surface and the inner peripheral surface. On the inner peripheral side of the annular wall 18, the cross section is curved in an arc shape,
An annular projecting portion 21 projecting inward is integrally formed. Further, a plurality of terminals 22 projecting downward are integrally formed by insert molding below the base 17 of the insulator 16, and one end of the terminal 22 is connected to one end of the stator coil 15.

The rotor 13 is formed of a synthetic resin in a cup shape, and has a disk-shaped main body 23 and a hollow cylindrical bush 25 formed in a hole 24 formed in the center of the main body 23. And a yoke 28 and a magnet 29 fixed to the inner peripheral surface of an outer peripheral wall 27 formed on the outer periphery of the main body 23. Axis 26
Are arranged so as to project vertically downward from the lower surface side of the main body portion 23, and a spherical portion 26a is formed at the lower end. An annular projection 30 is provided on the lower edge of the bush 25 so as to protrude outward. A plurality of blades (not shown) are provided on the outer peripheral surface of the outer peripheral wall 27 at intervals in the circumferential direction.

The housing 11 has a disk-shaped substrate portion 31.
And a hollow cylindrical portion 3 made of synthetic resin, which is fitted in a through hole 32 formed in the center of the substrate portion 31 and has both ends opened.
3 and a metal receiving member 34 having an open upper end side in which the sleeve bearing 12 is installed. The hollow cylindrical portion 33 has its upper end locked to the outer periphery of the metal receiving member 34. An annular convex portion 35 is provided on the inner peripheral surface of the upper end of the cylindrical portion 33. On the surface,
A step 36 is provided for engaging with the annular projection 35.

The sleeve bearing 12 has a through hole 37 at its center.
Are provided. A disk-shaped thrust bearing member 39 is provided at the tip of the shaft 26. An annular notch 40 is provided on the outer periphery of the upper end of the radial bearing member 38,
A circular notch 41 surrounding the through hole 37 is provided on the lower surface side. The radial bearing member 38 is made of, for example, a porous material made of a sintered metal that can be impregnated with oil, and the thrust bearing member 39 is made of, for example, a Teflon resin or a PPS-based composite resin.

The radial and thrust bearing members 38, 39 are formed by inserting the radial bearing member 38 into the metal receiving member 38 by positioning the thrust bearing member 39 on the inner bottom surface of the metal receiving member 34. It is positioned and installed by fitting the thrust bearing 39 to the notch 41,
In this state, the metal receiving member 38 surrounds the outer peripheries of the radial and thrust bearing members 38 and 39, and the metal on the stator 10 side is provided between the inner peripheral surface of the metal receiving member 38 and the annular notch 40 at the upper end. A space into which the bush 19 made is inserted is formed.

In FIG. 1, the member indicated by reference numeral 44 has mounted thereon electronic components such as a Hall element 42 for detecting the position of the magnet 29 of the rotor 13 and an IC 43 for controlling the current supplied by the stator coil 15. A printed circuit board, and the board 44 and the stator coil 15
It is electrically connected via the terminal 22. Next, a method of assembling the brushless motor having the above configuration will be described.
FIG. 2 is an exploded cross-sectional view of FIG. 1, and the brushless motor of the present invention has approximately four units A to A shown in FIG.
D is divided into sub-assemblies in advance and assembled by the following procedure. The unit A is a sub-assembly of the rotor 13. A bush 25 is interposed in a hole 24 provided at the center of the main body 23, the upper end of the shaft 26 is fitted and fixed, and the inner side of the outer peripheral wall 27. Has a yoke 28
And the magnet 29 are bonded and fixed.

The unit B is a sub-assembly of the stator 10 and includes a metal bush 19 and a terminal 2.
2 are integrally molded with the insulator 16 and the coil 15
Is mounted. The unit C is a sub-assembly of the metal receiving member 34 of the housing 11 and the radial and thrust bearing members 38, 39, and the radial and thrust bearing members 38, 39 are housed in the metal receiving member 34. .

The unit D is composed of the substrate 3 of the housing 11.
1 is a subassembly of the printed circuit board 44, and a hollow cylindrical portion 33 is provided integrally with the substrate portion 31. When assembling the motor using the units A to D, first, the unit C is attached to the unit D. The assembly of the unit C is performed from below the substrate unit 31. When the metal receiving member 34 is inserted from below into the hollow cylindrical portion 33 of the housing 11, the annular convex portion 35 provided on the inner peripheral surface of the hollow cylindrical portion 33 and the step portion 36 of the metal receiving member 34 are mutually connected. Engage, and thus, the metal receiving member 34 is assembled to the housing 11.

Next, units C and D are replaced with unit B.
Assemble. In this assembly, from below the unit B,
The metal receiving member 34 of the unit C is inserted from the center of the stator core 15, and the upper end of the metal receiving member 34 is inserted into the annular concave portion 20. At this time, the inner peripheral surface on the upper end side of the metal receiving member 34 and the outer peripheral surface on the lower end side of the metal bush 19 are tightly fitted to each other, and if necessary, the upper surface of the annular wall 18 of the insulator 16 is appropriately fitted. The support member 34 is supported by a jig.
Is applied from below to press the metal receiving member 34 into the metal bush 19.

The press-fitting operation of the metal receiving member 34 is performed until the tip of the metal receiving member 34 contacts the metal bush 19.
In this case, it is desirable to set the dimensions such that a slight gap is formed between the inner peripheral surface of the metal bush 19 and the annular cutout portion 40 of the radial bearing portion 38. Further, in this assembled state, the dimensions may be set so that the tip of the hollow cylindrical portion 33 contacts the lower surface of the stator core 14, and the stator core 14 may be positioned and supported by the hollow cylindrical portion 33.

When the unit B is assembled to the units C and D in this way, the unit A is finally assembled. The assembly of the unit A is performed by inserting the shaft 26 into the through hole 37 of the radial bearing member 38. In this case, in the process of inserting the shaft 26, the bush 2
5, the annular projection 30 interferes with the annular projection 21 of the insulator 16, but the annular projection 21 is made of synthetic resin and has a relatively small thickness. When the annular projection 30 passes through the annular projection 21, the projection 21 is restored to its original state by the elastic force.

When the spherical portion 26a of the shaft 26 comes into contact with the upper surface of the thrust bearing 39, the assembly of the unit A is completed. Thus, the assembly of the motor is completed. The mounting of the printed circuit board 44 is performed before the unit B is mounted, and the terminals 22 are soldered to the printed circuit board 44 after the unit B is mounted. Now, according to the brushless motor configured as described above, the stator 10
Are supported by press-fit portions of the metal bush 19 and the metal receiving member 34, and since these press-fit target members are all made of metal, almost no deformation occurs during press-fitting. Accordingly, in the process of assembling the motor, since no external force affecting the sleeve bearing 12 is applied, smooth rotation of the rotor 13 is ensured.

Further, according to the brushless motor of this embodiment, since the annular projection 21 is located above the sleeve bearing 12, even if the motor is turned upside down from the state shown in FIG. The oil impregnated in the bearing 12 is stored in the annular protrusion 21 to prevent leakage to the outside, and the metal bush 19 and the metal receiving member 34 are tightly fitted by press fitting. So
Oil is also prevented from leaking through the interface between these members.

[0023]

As described above in detail in the embodiments,
According to the brushless motor according to the present invention, smooth rotation can be ensured.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a brushless motor according to the present invention.

FIG. 2 is an explanatory view of a process of assembling the motor shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Stator 11 Housing 12 Sleeve bearing 13 Rotor 14 Stator core 15 Stator coil 16 Insulator 19 Metal bush 29 Magnet 34 Metal receiving member

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H02K 29/00 H02K 5/16 H02K 5/167 H02K 21/00

Claims (1)

(57) [Claims] 1. A brushless motor comprising: a housing on which a stator is mounted; and a rotor rotatably supported on the housing via a sleeve bearing, wherein the stator includes a stator core, a stator coil,
An insulator on which the core and the coil are mounted; and a hollow cylindrical metal bush integrally formed with the insulator. The rotor is opposed to a shaft portion inserted into the sleeve bearing and the stator core. The housing surrounds the outer periphery of the sleeve bearing, the stator core is fitted to the outer periphery, and an opening edge at an upper end has a metal receiving member pressed into the metal bush. Features brushless motor.