JP2003111316A - Stator support mechanism, manufacturing method for the stator support mechanism, and brushless motor provided with the stator support mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stator support mechanism which is simple in structure and yet rigid and reliable and a brushless motor provided with the support mechanism. SOLUTION: A bearing housing 1 made of synthetic resin is formed by a resin molding method called outsert molding coaxially with a bottom hole 2a formed in a stator base 2 formed of a sheet metal of iron, aluminum, or the like. A thrust bearing retaining portion 1a is formed on the bottom of the bearing housing 1; a radial bearing retaining portion 1b is formed on the inner circumferential surface thereof; a core anchoring stepped portion 1c, a core fitting portion 1d, and core anchoring projected portions 1e are formed on the outer circumferential surface thereof; and slits 1f are formed in proximity with the open end 1g thereof. Since a plurality of the slits 1f are formed in the direction of the axis of the bearing housing 1, a plurality of the core anchoring projected portions 1e are formed in proximity with the peripheral edge of the end 1g of the bearing housing 1 in appentice shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of an outer rotor type brushless motor. More specifically, the present invention relates to a stator support mechanism and a brushless motor including this mechanism.

[0002]

2. Description of the Related Art An outer rotor type brushless motor has a structure in which a bearing housing is fixed to the center of a stator base that supports a stator, and the bearing housing is inserted into the center of a cup-shaped rotor yoke. It holds a radial bearing and a thrust bearing that rotatably support the mounted shaft. An annular magnet having a plurality of magnetic poles is fixed to the inner peripheral surface of the cup-shaped rotor yoke. A stator having an armature around which a coil is wound is fixed to the outer peripheral portion of the bearing housing so as to face the magnetic pole of the annular magnet. That is, in this stator, a stator core having a plurality of arms protruding in the radial direction from the center is laminated, and a drive coil is wound around the arms to form an armature magnetic pole.

In the structure of the motor, the bearing housing is generally formed by cutting a metal rod material such as brass or steel into a cylindrical shape having a bottom, and the diameter of the inner peripheral portion is the radial bearing. Is slightly smaller than the outer diameter of the stator core, the diameter of the outer peripheral end is slightly larger than the center hole of the stator core, and the bottom diameter is slightly larger than the fitting hole of the stator base bearing housing.

The stator base is formed by punching a metal plate such as iron or aluminum by pressing.
Fitting holes for the outer shape and the bearing housing are formed. A printed circuit board is mounted on the surface of the stator base on the stator side, and components for motor drive control such as Hall elements for detecting the position of the stator magnetic pole are mounted.

In order to construct the support portion of the stator by using the components thus formed, the bearing is first inserted into the bearing housing at the inner peripheral portion thereof, and then inserted into the bearing housing fitting hole of the stator base. After mounting, the periphery of the insertion part is fixed by caulking, etc., and further, the stator core around which the drive coil is wound is inserted in the insertion part of the stator core of the bearing housing, and the vicinity of the periphery of the insertion part of the stator core is fixed by caulking. It was

[0006]

However, in the structure of the stator constructed as described above, the fitting portions of the parts are fitted with the stator core in the bearing housing and the bearing housing in the stator base. Although there are two parts, the easy fitting of each part in any fitting part causes a problem that the fitting gap becomes large and the caulking strength at the time of sticking is reduced and the axis of the stator is misaligned with respect to the rotor. . In particular, the axial displacement of the rotor causes rotational runout, which is a serious problem when the motor is used as a rotational drive source for the information recording medium.

Further, the process of cutting the bearing housing is complicated, and the cutting size varies greatly. Furthermore, in order to improve the strength and reliability of the fixing of the two caulked portions, the caulking work is combined with the adhesive application work.
Heavy work was being done. In addition to this, when the stator core is fixed to the bearing housing, there arises a problem that the fixed positions of the stator magnetic pole and the Hall element for position detection are displaced. This deteriorates the efficiency of the motor itself and, in the worst case, causes the motor to be unable to rotate.

The present invention solves the above-mentioned drawbacks.
A strong fixing is achieved simply by inserting the stator core into the bearing housing, and the bearing housing is formed integrally with the stator base to provide a simplified structure, but a robust and highly reliable stator support mechanism. And a brushless motor provided with this support mechanism.

[0009]

In order to solve the above-mentioned problems, as in the invention described in claim 1, a bearing for supporting a rotary shaft of a rotor is held on an inner peripheral portion and a stator is mounted on an outer peripheral portion. In a motor stator support mechanism comprising a fixed bearing housing, the bearing housing is made of synthetic resin, and has an eaves-like shape having an outer diameter larger than a central hole diameter of a stator core provided at a peripheral edge of an end into which the stator core is fitted. It can be achieved by having a plurality of convex portions and a fitting portion of the stator core divided by a slit provided in the axial direction of the bearing housing from an end portion into which the stator core is fitted.

In addition, the bearing housing may be the one described in claim 2.
As in the invention described in claim 3, a concave groove is provided in the outer peripheral portion in the axial direction of the central hole of the stator core, and a convex portion that fits into the concave groove is provided in the fitting portion of the stator core. As in the invention, it can be achieved by forming the inner peripheral portion as the radial bearing holding portion, providing the outer peripheral surface of the radial bearing with the concave groove in the axial direction, and providing the convex portion fitted with the concave groove.

The manufacturing method of the stator support mechanism of the present invention is
According to the invention described in claim 4, after the stator core around which the drive coil of the motor is wound is fitted into the bearing housing in the stator support mechanism according to claim 1, the radial direction is provided on the inner peripheral portion of the bearing housing. This can be achieved by press-fitting the bearing and fixing the stator core to the bearing housing.

Further, the bearing housing can be achieved by being integrally assembled with the stator base by outsert molding, as in the invention described in claim 5.

Further, a brushless motor having a structure which is excellent in assembling workability and has a simplified structure, but which is robust and excellent in reliability has a stator support mechanism described in claim 5 as in the invention described in claim 6. This can be achieved by supporting the rotary shaft of the rotor with a bearing held on the inner peripheral portion of the above and fixing the stator to the outer peripheral portion thereof.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional front view of essential parts showing an embodiment of a bearing housing according to the present invention, and FIG. 2 is a partially cutaway perspective view for further explaining the bearing housing of the present invention. 1 and 2, a bearing housing 1 made of a synthetic resin is formed coaxially with a prepared hole 2a of a stator base 2 made of a metal thin plate such as iron or aluminum by a resin molding method called outsert molding. There is.

The outsert molding method is a general molding method in recent years, in which a substrate such as metal or plastic is sandwiched between molding dies, and pins or bush-shaped functional parts are attached at once by molding once. There is. As described above, the bearing housing 1 shown in FIG. 1 has a stator base 2 and a molding die in which the shape of the bearing housing 1 is engraved in the cavity and the core.
A synthetic resin bearing housing 1 is directly attached to a stator base 2 made of metal by sandwiching and sandwiching the synthetic resin by injection or compression.

Bearing housing 1 formed as described above
The thrust bearing holding portion 1a at the bottom, the radial bearing holding portion 1b at the inner peripheral portion, the core locking step portion 1c and the core fitting portion 1d, the core locking convex portion 1e, and the slit 1f from the opening end portion 1g on the outer circumference. It is provided along the axial direction. Since the slits 1f are provided in plural, the core locking protrusion 1
A plurality of e are provided in the shape of an eave near the peripheral edge of the end 1g of the bearing housing 1.

3 and 4 are views for explaining the method of manufacturing the stator. First, as shown in FIG. 3 (A), the thrust bearing 3 is inserted from the direction of the opening end 1g of the bearing housing 1 and is attached to the thrust bearing holding portion 1a. Next, as shown in FIG. 3 (B), when the stator A having the stator core 5 laminated, insulated and wound around the drive coil 6 is inserted from the opening end 1g direction of the bearing housing 1, slits are formed. Since the outer diameter of the core locking protrusion 1e is set to be larger than the central hole diameter of the stator A by 1f, the core locking protrusion 1
e is bent in the direction of the inner peripheral portion so that the outer shape has a V shape, and the stator A can be easily fitted.

Further, the core fitting portion 1d of the bearing housing 1
Is set to be equal to or slightly larger than the thickness of the stator A, so that when the stator A is fitted and is fitted into the core fitting portion 1d, the outer diameter of the core locking convex portion 1e is returned to the original size. The return stator A is the core locking protrusion 1e of the bearing housing 1.
Locked in.

FIG. 3C shows a fixing method for further firmly locking the bearing housing 1 and the stator A together. Figure 3 (B)
In this state, the radial bearing 4 is inserted from the opening end 1g of the bearing housing 1 to a predetermined position. Here, since the diameter of the radial bearing holding portion 1b of the bearing housing 1 is set to be smaller than the outer diameter of the radial bearing 4 in units of microns, the insertion is a press fit and the outer diameter of the core fitting portion 1d of the bearing housing 1 is expanded to the outside. Will be done. This expanded portion bites into the insertion holes of the individual stator cores 5 that constitute the stator A, and the stator A is
It is firmly fixed to the core fitting portion 1d of the bearing housing 1. FIG. 4 shows this state.

FIG. 5 is a sectional view showing the structure of a motor having a stator according to the present invention. In FIG.
The bearing housing 1 is fixed to a central portion of a stator base 2, and a thrust bearing 3 and a radial bearing 4 are inserted into the inside of the bearing housing 1 to rotatably support a shaft 9. The shaft 9 is inserted into the central portion of the cylindrical rotor yoke 7, and an annular magnet 8 having a plurality of magnetic poles is fixed to the inner circumference of the cylinder of the rotor yoke 7. A stator A, which constitutes an armature and faces the magnet 8, is fixed to the outer circumference of the bearing housing 1.
In the stator A, the drive coil 6 is wound around a plurality of arms protruding in the radial direction from the central portion of the stator core 5 to form an armature magnetic pole.

The bearing housing 1 described above is provided with a rotation stopper. As shown in FIGS. 1 and 2, the base portion 1 of the bearing housing 1 is in contact with the lower hole 2a of the stator base 2.
By providing a rotation stop hole 2b in the annular portion of h and bypassing the synthetic resin forming the bearing housing 1 through the rotation stop 2b, the resin-molded bearing housing 1
It is intended to prevent rotation due to external force. The whirl-stop hole 2b may be provided with a concave groove portion or a raised portion in the lower hole 2a of the stator base, but as shown in FIG.
The bent portion 32b may be formed by forming a protrusion on the inner edge of the lower hole 32a.

7 and 8 show a modification of the embodiment of the present invention. FIG. 7 shows a case in which eaves-shaped core engaging projections 11e are provided on a part of the peripheral edge of the opening end 11g between the slits 11f of the bearing housing 11. This has the effect of making it easier to insert the central hole of a small-sized stator core into the bearing housing. Also,
FIG. 8 shows the slit portion 21f of the bearing housing 21 in FIG.
The number is further increased, and the eaves-shaped core locking convex portion 21e is made finer. This has the effect of improving the workability of insertion because the force for bending the core locking convex portion 21e can be reduced.

FIG. 9 is a view for explaining another modification of the embodiment of the present invention, which is a view of the stator locking projection of the bearing housing cut in the radial direction and viewed in the stator base direction. In FIG. 9, a convex portion 31i is provided in the axial direction on a core fitting portion 31d on the outer diameter portion of the bearing housing 31. Further, the central hole 35a of the stator core 35 is provided with a concave groove portion 35b that fits into the convex portion 31i on the inner periphery of the core fitting portion 31d of the bearing housing 31. This is because when the stator core 35 is fitted into the bearing housing 31, the protrusion 3
By fitting 1j into the concave groove 35b, each magnetic pole of the stator can be fixed at a fixed position at all times, so that a magnetic pole detection element (not shown) such as a Hall element that deteriorates the characteristics of the motor itself is used. There is no displacement.

Further, in FIG. 9, the bearing housing 3
The protrusion 31j is provided on the radial bearing holder 31b at the inner peripheral portion of
Are provided in the axial direction. Further, the radial bearing holding portion 31b of the bearing housing 31 is provided on the outer periphery of the radial bearing 4.
A recessed groove portion 4a that fits in is provided. This is because when the radial bearing 4 is press-fitted into the bearing housing 31, the raised portion 31j of the radial bearing holding portion 31b is fitted into the concave groove portion 35b of the radial bearing 4 so that the radial bearing 4 is
It prevents the rotation due to the rotation torque.

[0025]

As described above, according to the first aspect of the present invention, a motor having a bearing housing that holds a bearing for supporting the rotation shaft of the rotor on the inner peripheral portion and fixes the stator on the outer peripheral portion. In the stator support mechanism, the bearing housing includes a plurality of eave-shaped protrusions made of synthetic resin and having an outer diameter larger than the central hole diameter of the stator core provided at the peripheral edge of the end into which the stator core is fitted. It is possible to provide by providing the stator core fitting portion divided from the end portion into which the stator core is fitted by a slit provided in the axial direction of the bearing housing.

The bearing housing may be the
According to the invention described in (1), a concave groove is provided in the outer peripheral portion in the axial direction of the central hole of the stator core, and a convex portion that fits with the concave groove is provided in the fitting portion of the stator core. According to the invention, it is possible to provide by providing the inner peripheral portion as the radial bearing holding portion, providing the outer peripheral surface of the radial bearing with the concave groove in the axial direction, and providing the convex portion fitted with the concave groove.

The manufacturing method of the stator support mechanism of the present invention is as follows.
According to the invention described in claim 4, after the stator core around which the drive coil of the motor is wound is fitted into the bearing housing in the stator support mechanism according to claim 1, the radial direction is provided on the inner peripheral portion of the bearing housing. It can be provided by press-fitting the bearing and fixing the stator core to the bearing housing.

Further, according to the invention described in claim 5, the bearing housing can be provided by being integrally assembled with the stator base by outsert molding.

According to the invention described in claim 6, a brushless motor having a structure which is easy to assemble and has a simplified structure, but which is robust and excellent in reliability is provided. It can be provided by supporting the rotary shaft of the rotor by the bearing held at the inner peripheral portion of the above and fixing the stator to the outer peripheral portion thereof.

[Brief description of drawings]

FIG. 1 is a cross-sectional front view of essential parts showing an embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view for explaining the embodiment of the present invention shown in FIG.

FIG. 3 is a diagram illustrating a stator manufacturing method according to the present invention.

FIG. 4 is a diagram illustrating a stator manufacturing method according to the present invention.

FIG. 5 is a partially cutaway front view showing the structure of a motor including a stator according to the present invention.

FIG. 6 is a main-portion cross-sectional view showing a modification of the embodiment of the present invention.

FIG. 7 is a perspective view showing a modified example of the embodiment of the present invention.

FIG. 8 is a perspective view showing a modified example of the embodiment of the present invention.

FIG. 9 is a partially cut plan view showing another modification of the embodiment of the present invention.

[Explanation of symbols] 1 Bearing housing 1a Thrust bearing holder 1b Radial bearing holder 1c Core locking step 1d core fitting part 1e Core locking protrusion 1f slit part 1g Open end 1h outer diameter base 2 Stator base 2a pilot hole 2b detent

Continued front page    F-term (reference) 5H002 AA07 AA08 AB05 AC06 AC08                 5H019 AA10 CC04 DD01 EE01 EE14                       FF03                 5H605 AA08 BB05 BB19 EB02 EB06                       EB17 FF06 GG04                 5H615 AA01 BB01 BB07 BB14 BB16                       PP01 PP06 PP25 SS05 SS19                       TT26

Claims (6)

[Claims] 1. A stator supporting mechanism for a motor, comprising: a bearing housing for supporting a rotary shaft of a rotor on an inner peripheral portion thereof; and a stator housing for fixing a stator on an outer peripheral portion thereof, wherein the bearing housing is made of synthetic resin. , A plurality of eave-shaped protrusions having an outer diameter larger than the central hole diameter of the stator core provided at the periphery of the end where the stator core is fitted, and an axial direction of the bearing housing from the end where the stator core is fitted. A stator support mechanism having a stator core fitting portion divided by a slit provided in the. 2. The stator support mechanism according to claim 1, wherein a recessed groove in the axial direction is provided in a central hole of the stator core, and a convex portion that fits into the recessed groove is provided in a fitting portion of the stator core. 3. The method according to claim 1, wherein an inner peripheral portion of the bearing housing serves as a radial bearing holding portion, a concave groove is provided in an axial direction of an outer peripheral surface of the radial bearing, and a convex portion that fits the concave groove is provided. The described stator support mechanism. 4. The stator support mechanism according to claim 1, wherein a stator core around which a motor drive coil is wound is fitted into the bearing housing, and then a radial bearing is press-fitted into an inner peripheral portion of the bearing housing. A manufacturing method of a stator support mechanism for fixing a stator core to a bearing housing. 5. The stator support mechanism according to claim 1, wherein the stator support mechanism is integrated with the stator base by outsert molding. 6. A brushless motor in which a rotating shaft of a rotor is supported by a bearing held by an inner peripheral portion of the stator support mechanism according to claim 5, and a stator is fixed to an outer peripheral portion of the rotor.