JPH0538118A - Brushless motor - Google Patents

Abstract

PURPOSE:To provide a brushless motor, wherein its winding work can be made simple and made easy, and moreover, its reliability is improved. CONSTITUTION:In a brushless motor, provided are a stator, whose shape is nearly cylindrical and on whose inner peripheral surface a plurality of magnetic poles 3 are formed protrusively, coils 5 each of which is wound around the magnetic pole via a coil frame 6, a stator block 1 molded with a resin, in which only the inner peripheral surfaces 3a of the magnetic poles are exposed, a rotor block 11, and bearing bases fastened to both the end of the stator block, which are located in the direction of the shaft of the stator block. In the brushless motor, the stator 2 is so formed, before molding it with the resin, as to divide it into an outer ring part 4, whose shape is nearly cylindrical, and a plurality of magnetic pole parts 3, 3,....

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless electric motor having a resin-molded stator block and a rotor block surrounded by the stator block.

[0002]

2. Description of the Related Art In recent years, in order to reduce the noise of brushless motors,
The number of resin molds for stator blocks is increasing.
Such a brushless electric motor has a stator block, a rotor block, and a bearing stand as main constituent members, and has a configuration shown in FIG. 5 in a cross section.

The stator block 1 is formed by punching and stacking iron plates, has a substantially cylindrical shape, and has a stator 2 having a plurality of magnetic poles 3 projecting from the inner peripheral surface thereof, and a coil around the magnetic poles 3. It includes a coil 5 wound around a frame 6 and an electric wiring board (not shown) that supports and connects the magnetic sensitive element and the terminal of the coil, and exposes the inner peripheral surface 3a of the pole piece 3 to expose them. It is formed by resin molding so as to cover it with the resin layer 9. A thermosetting resin such as unsaturated polyester is often used as a material for the resin layer 9, and an appropriate number of attachment holes (not shown) are used.
Or the drive circuit board may be embedded in some cases.

The rotor block 11 includes a rotor shaft 12, a cylindrical yoke 13 fixed to the outer circumference of the rotor shaft 12, and a plurality of segment magnets 14 and 14 fixed to the outer circumference of the yoke 13 by adhesion or the like. , -And.

Two bearing pedestals (not shown) have bearings for supporting the rotor shaft 12, and further have attachment holes corresponding to the attachment holes of the stator block 1, and both attachment holes are It is fixed to both axial ends of the stator block 1 by matching and screwing the screws.

Such a brushless electric motor has a rotor block 11
The polarities of the segment magnets 14, 14, are detected by a magnetically sensitive element, and a drive circuit (not shown) appropriately controls energization of the coil 5 to rotate the rotor block 11. Further, since the stator block 1 exposes only the inner peripheral surface 3a of the pole piece 3 and covers the other portion with the resin layer 9, the vibration noise of itself can be reduced.

[0007]

SUMMARY OF THE INVENTION The above-mentioned conventional one is a winding work for the coil 5 wound around the pole piece 3,
There is a problem that the shape of the stator is restricted due to the work. That is, the coil 5 is wound by a special winding machine as shown in FIG. The nozzle N of the winding machine W has a small diameter base Na and a large diameter end Nb, and the small diameter base Na has one pole piece 3
However, when moving in the vertical direction in the figure, the small diameter base Na enters between the adjacent magnetic poles 3, 3. Therefore, these circumferential widths, which determine the gap between the pole pieces 3 and 3, must be at least the small diameter base of the nozzle N.
The constraint is that Na must be able to form a gap into which it can enter and move. Since the small diameter base Na of the nozzle N moves slightly, it is necessary to reduce the moving speed (winding speed) so that it does not come into contact with the magnetic pole pieces 3 and 3 or uneven winding and disconnection. However, the winding work takes time.

The present invention has been made in view of the above circumstances, and its purpose is to simplify the winding operation,
Moreover, it is to provide a brushless electric motor that can improve reliability.

[0009]

In order to solve the above problems, a brushless electric motor of the present invention is formed by punching and stacking iron plates and has a substantially cylindrical shape, and a plurality of magnetic poles are projected on the inner peripheral surface. An inner peripheral surface of the magnetic pole piece is provided including a stator provided, a coil wound around the magnetic pole piece through a coil frame, and an electric wiring board that supports and connects the magnetic sensitive element and the terminal of the coil. A stator block formed by resin molding so as to expose and cover them, a rotor shaft, a cylindrical yoke fixed to the outer circumference of the rotor shaft, and a plurality of segment magnets fixed to the outer circumference of the yoke, In a brushless electric motor having a rotor block made of, and bearing bases having bearings for supporting the rotor shaft and fixed to both ends in the axial direction of the stator block, the stator is before resin molding. Roughly cylindrical It has a configuration which is separately formed on to the outer ring portion and a plurality of Jikyokuko portion.

[0010]

According to this structure, since the stator is separately formed into the outer ring portion and the plurality of magnetic pole portions before the resin molding process, the coil can be operated at high speed by an ordinary winding machine regardless of the stator. Thus, the coil frame can be wound around, the coil frame is attached to the magnetic pole piece, the magnetic pole piece is joined to the outer ring part, and resin molding is performed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the brushless motor of the present invention will be described below with reference to FIGS. The same reference numerals are given to the members related to the members of the conventional example.

This brushless electric motor has a stator block 1, a rotor block 11 and a bearing base 21 as main constituent members as in the case of the conventional example, and only the stator block 1 of them is different from the conventional example. It is different.

Finally, the stator block 1 is formed by punching and stacking iron plates and has a substantially cylindrical shape, as in the conventional example, and a stator 2 having a plurality of magnetic poles 3 protruding from the inner peripheral surface thereof. , The coil 5 wound around the pole piece 3 via the coil frame 6, and the electric wiring board 7 for supporting and connecting the magnetic sensitive element 8 and the terminals of the coil 5, and the inner peripheral surface of the pole piece 3 3a
Are exposed and resin-molded so as to cover them with the resin layer 9, and the resin layer 9 is provided with an appropriate number of attachment holes 9a. However, the stator 2 has a substantially cylindrical outer ring portion 4 and a plurality of pole piece portions before the resin molding process.
(Pole piece) 3, 3 are separately formed.

The pole piece 3 is formed by punching and stacking iron plates, and has a substantially T-shaped base 3b and a substantially crescent tooth 3c, and the base 3b has a distal end. An inverted triangular fixing protrusion 3d is formed. The outer ring portion 4 is formed by punching and stacking iron plates and corresponds to the cylindrical portion of the stator 2, and has a cylindrical shape with a width that does not cause magnetic flux leakage. Fixing recesses 4d, 4d, -corresponding to the fixing protrusions 3d are formed.

The coil 5 is wound around the coil frame 6 by an ordinary winding machine separately from the magnetic pole piece 3 and the outer ring portion 4 as described above. The coil frame 6 is composed of a tubular portion 6a having an inner hole having a cross-sectional area slightly larger than the cross-sectional area of the base portion 3b of the magnetic pole piece 3, and collar portions 6b and 6b connected to both ends thereof. Next, the coil frames 6,6, with the coils 5,5 wound around are the pole pieces 3,3,
Is attached to the bases 3b, 3b of the magnetic poles 3b, 3b, and then the coil frame 6 is attached.
It is bonded and fixed to the fixing recesses 4d, 4d, of 4 by press fitting or adhesion. In this way, after the magnetic pole pieces 3, 3 are fixed to the outer ring portion 4 to form the stator 2 similar to the conventional one, the resin molding process described above is performed.

FIG. 4 shows a resin molding process for forming the resin layer 9, that is, a state of molding. Lower mold 31
Has an annular recess 31a whose inner diameter is equal to the inner peripheral surface 3a of the pole piece 3 and whose outer diameter is slightly larger than the outer circumference of the outer ring portion 4, and the electrical wiring board is located on the bottom surface of the annular recess 31a. A pillar 31b is formed for supporting 7 and attaching hole 9a. The upper die 32 is an annular recess
It has a shallower annular recess 32a corresponding to 31a, and a column (not shown) for the attachment hole 9a is formed on the bottom surface thereof. Further, the injection hole 32c is provided in a range where the coil 5 exists in the radial direction. 33 is a pot for containing a molding material, 34 is a thermosetting molding material such as unsaturated polyester, 35 is a plunger for extruding the molding material, and this molding die has a transfer molding die structure. There is. The unsaturated polyester of the molding material 34 has an extremely low viscosity when heated and melted, can surely fill every corner of the mold, and has good adhesion with each member.

The stator block 1 is molded by charging the preheated molding material 34 into the pot 33 and heating the upper and lower molds.
While the 31 and 32 are butted against each other with a predetermined mold clamping force, the molding material 34 is filled into the mold through the injection hole 32c as the plunger 35 descends. The resin layer 9 can be formed in the gap.

The rotor block 11 includes a rotor shaft 12, a cylindrical yoke 13 fixed to the outer periphery of the rotor shaft 12, and a plurality of rotor blocks 11 fixed to the outer periphery of the yoke 13 by adhesion or the like (4 in this embodiment). Individual segment magnets 14,14,-.

The two bearing bases 21 and 21 have bearings 22 and 22 for supporting the rotor shaft 12, and further mounting holes 21a and 21a corresponding to the mounting holes 9a and 9a of the stator block 1, respectively. It has, insert the rotor block 11 described above into the stator block 1,
While inserting the rotor shaft 12 into the bearings 22 and 22, both attachment holes 9a,
21a are fitted and screwed with screws (not shown) to fix them to both ends of the stator block 1 in the axial direction.

Such a brushless electric motor has a rotor block 11
The polarities of the segment magnets 14, 14, are detected by the magnetic sensitive element 8, and a drive circuit (not shown) controls the energization of the coil 5 as appropriate to rotate the rotor block 11.

Since the stator is separately formed into the outer ring portion and the plurality of magnetic pole portions before the resin molding process,
The coil can be wound around the coil frame at high speed with a normal winding machine regardless of the stator, thus reducing the manufacturing cost of the winding and also damaging the pole piece and the coil wire during winding. Almost disappeared, and further, there is no restriction on the gap between the circumferential end portions of the adjacent magnetic poles, so that the optimum magnetic pole shape can be adopted.

Since the rotor block and the bearing stand are not the essential parts of the present invention, they can be appropriately modified. That is, for example, the segment magnets of the rotor block are not limited to those having a plurality of clearly separated magnets as in the embodiment, but may be cylindrical magnets having a plurality of different poles alternately. ..

[0023]

In the brushless electric motor of the present invention, since the stator is separately formed on the outer ring portion and the plurality of magnetic pole portions before the resin molding process, the coil is a normal winding regardless of the stator. It can be wound around the coil frame at high speed with a machine, and it almost eliminates damage to the pole piece and coil wire material during winding, and there is no restriction on the gap between the circumferential ends of adjacent pole pieces, which is ideal. The magnetic pole shape of can be adopted,
Therefore, the winding work can be simplified and the reliability can be improved.

[Brief description of drawings]

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

FIG. 2 is an exploded perspective view thereof.

FIG. 3 is an exploded perspective view of a main part thereof.

FIG. 4 is a cross-sectional view showing a state at the time of molding.

FIG. 5 is a cross-sectional view showing a conventional example.

FIG. 6 is a perspective view of a main part showing a winding state thereof.

[Explanation of symbols]

 1 Stator block 2 Stator 3 Pole piece (pole piece) 3b Base section 3c Teeth section 4 Outer ring section 5 Coil 6 Coil frame 7 Electric wiring board 8 Magnetic sensitive element 9 Resin layer 11 Rotor block 21 Bearing block

Claims (1)

Claim: What is claimed is: 1. An iron plate is punched and laminated to form a stator having a substantially cylindrical shape and a plurality of magnetic poles protruding from an inner peripheral surface thereof, and a coil frame around the magnetic poles. A stator that includes a coil wound through a coil and an electric wiring board that supports and connects the magnetic sensitive element and the terminal of the coil, and is molded by resin molding so as to expose the inner peripheral surface of the pole piece and cover them. A rotor block composed of a block, a rotor shaft, a cylindrical yoke fixed to the outer circumference of the rotor shaft, a plurality of segment magnets fixed to the outer circumference of the yoke, and a bearing supporting the rotor shaft. And a bearing base fixed to both ends in the axial direction of the stator block, and the stator has a substantially cylindrical outer ring portion and a plurality of magnetic pole portions before resin molding. Is formed separately Brushless electric motor that characterized the door.