JP2912094B2 - Small molded 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 compact molded motor, and more particularly to a structure of an oil-impregnated bearing hole.

[0002]

2. Description of the Related Art As shown in FIG. 5, a conventional small molded motor has an iron core 5 on which a driving coil 4 is wound via an insulating film 2 and a resin mold 3 using a molding die. A bearing press-fitting hole 6 concentric with the outer periphery of the iron core 5 is formed at the same time as being integrally molded with a base of a device or the like on which a motor is to be mounted.

In this conventional small-sized molded motor, the bearing press-fitting hole 6 is formed by a resin 3 having a high oil absorption such as unsaturated polyester. Oil is sucked out, and the lubricating effect of the bearing is remarkably reduced, which causes a problem of seizing of the shaft.

[0003] In addition, deformation of the resin due to the sucked oil,
Another problem is that the characteristics of other electronic components may change.

In order to avoid direct contact between the oil-impregnated bearing and the resin, a method of fixing the oil-impregnated alloy bearing 1 to the outer periphery of the oil-impregnated alloy bearing via a metal sleeve 1a such as brass as shown in FIG. Had to be taken.

[0005] Further, since the resin 3 forming the bearing press-fitting hole 6 is hard, when the oil-impregnated alloy bearing 1 is press-fitted and fixed, there is a drawback that the press-fit stress increases the variation in the inner diameter of the oil-impregnated bearing 1. Required sizing with a sizing bar after press-fitting. This has been a factor in increasing costs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a small-sized molded motor in which the metal sleeve on the outer periphery of the oil-impregnated alloy bearing is not required, and the sizing of the inner diameter of the oil-impregnated alloy bearing is not required.

[0007]

In order to achieve the above object, in a small-sized molded motor according to the present invention, an iron core to be wound is formed of a resin to form an insulating film, and a center portion of the iron core is formed. When the stator having the bearing press-fitting hole concentric with the outer peripheral portion is integrally molded with a mounting base of the motor itself or a device or the like to which the motor is to be mounted with hard resin, the inner diameter of the bearing press-fitting hole is Is to mold the hard resin so as not to enter.

When the rigid resin is integrally molded with a mounting structure of the motor itself or a base of a device to which the motor is to be mounted, the inner diameter of the bearing press-in hole is determined with reference to the outer diameter of the iron core. On which a film of the hard resin is formed.

[0009]

According to the small-sized molded motor of the present invention, when the insulating film between the drive winding and the iron core is formed in a molding die by using a soft resin without oil absorption, a cylinder concentric with the outer periphery of the iron core is formed at the center of the iron core. A sleeve is simultaneously provided to form a bearing press-fit hole. Thereafter, the drive winding is mounted, and the entire stator portion is formed and fixed to a part of the mounting structure of the motor itself or to a part of a base such as a device to which the motor is to be mounted with hard resin by double molding. At this time, by preventing the inner diameter of the cylindrical sleeve from entering a hard resin, even if the oil-containing bearing is press-fitted, seepage of oil can be prevented.

[0010] Further, at the time of the double molding, a resin coating of the hard resin having an inner diameter based on the outer diameter of the stator is formed on the inner diameter of the cylindrical sleeve, so that the oil-impregnated bearing is formed in the press-fit hole. The degree of concentricity with respect to the outer diameter of the stator can be made higher, and seepage of oil from the oil-containing bearing can be minimized.

[0011]

Next, the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a sectional view showing Embodiment 1 of the present invention.

In FIG. 1, an insulating coating 2 is formed of a soft resin (nylon, polyacetal resin, etc.) having no oil absorption in order to dispose a drive winding 4 on an iron core 5 and, at the same time, a cylindrical shape concentric with the outer periphery of the iron core 5. A sleeve 2a is provided. FIG. 4 shows a state in which the drive windings 4 are provided. Furthermore, the mounting structure 9 is formed by double-molding the hard resin 3 of the stator portion on which the drive winding 4 is mounted. Then, the bearing press-fit hole 6
The oil-impregnated alloy bearing 1 is press-fitted therein.

FIG. 3 is a sectional view showing an assembled state. 7, an output shaft; and 8, a rotor.

(Embodiment 2) FIG. 2 is a sectional view showing an embodiment of the present invention. In the present embodiment, the cylindrical coating portion 3a is also provided on the inner surface of the cylindrical sleeve 2a using the resin 3, and the bearing press-fit hole 6 concentric with the outer periphery of the iron core 5 is formed.

(Embodiment 3) Next, the manufacturing process of the third embodiment will be described more specifically with reference to the drawings.

FIG. 6 shows the iron core 20. The iron core 20 has twelve radially formed magnetic poles 22. At the tip of the magnetic pole 22, a magnetic field line generating surface 24 is formed in a curved shape. The tip of the magnetic pole 22 has a T-shape, and protrudes (2
3) Yes. A through hole 25 is formed in the center of the iron core, and three (only two shown) holes 26 are formed around the hole 25.

First, a cylindrical sleeve and an insulating coating of the magnetic pole 22 are formed in the through hole 25 of the iron core 20. This forming method is a so-called outsert molding in which a molded component is sandwiched between molds, and a melted resin is poured into a gap appropriately provided between the mold and the component, and the resin is solidified and then discharged from the mold.

FIG. 7 shows a lower mold 30 of the mold used for the outsert molding, and FIG. 8 shows an upper mold 40 of the mold.
The lower mold 30 is formed of a metal material for a mold, and has a cylindrical recess 3.
4 are provided. At the center of this dent is a slightly lower dent 36, at the center of which is a cylindrical projection 31.
There is. Each dimension is set so that the iron core 20 fits into the depression of the lower die 30. The side surface 32 at the tip of the T-shaped groove 33 is in close contact with the surface 24 of the iron core 20. That is, the horizontal positioning of the iron core 20 with respect to the lower mold 30 is performed with reference to the surface 32. Thereby, the projection 31 is positioned at the center of the hole 25 of the iron core 20. In addition, depression 3
The diameter of 6 is slightly larger than the hole 25 of the iron core 20. The lower surface of the iron core 20 is in close contact with the lower surface 35 of the depression 34 of the lower die 30. The surface 35 is used as a reference for the vertical positioning of the iron core 20 with respect to the lower mold 30. The surface other than the surface 32 of the groove 33 is
It is slightly separated from the facing surface of the projection 22 of the mounted iron core 20. The upper mold 40 is formed of a metal material for a mold, and has a smooth surface 45.
A columnar projection 41 is provided on the top. At the center of the columnar projection 41, there is a circular depression 43, in which a cylindrical hole 42 is further provided. A smooth surface 4 on the upper surface of the projection
There are four.

Next, outsert molding will be described with reference to FIG. The iron core 20 is fitted into the recess 34 of the lower mold 30 as described above, and pressed by the upper mold 40 from above. Upper mold 40
The flat surface 44 of the projection 41 presses the iron core 20 against the flat surface 35 of the lower die 30. The smooth surface 45 of the upper mold 40 is in close contact with the smooth surface 37 of the lower mold 35. Further, the smooth surface 46 in the hole 42 of the upper mold 40 is in close contact with the upper surface of the projection 31 of the lower mold 30.
Thereby, as shown in FIG. 9B, a gap is formed in each part. The melted resin is poured into the gap and solidified. A thin resin film is formed on a portion of the iron core 20 except for the surface 24 of the magnetic pole 22 and the lower surface of the iron core. Hole 2 in iron core 20
In 5, a cylindrical resin member having the same inner diameter as the outer periphery of the cylindrical protrusion 31 of the lower die 30 is formed. The iron core 20 on which the resin portion is formed is removed from the mold, and the windings 50 are formed on the magnetic poles 22 to complete the motor stator assembly 52 shown in FIG. The cylindrical resin member 51 is the cylindrical sleeve of the first embodiment described above.

As is apparent from the above description of the manufacturing process, the inner diameter of the cylindrical sleeve is formed by the projection 31 of the lower mold 30, and the iron core 20 is positioned in the horizontal direction by the lower mold 30. That is, according to this manufacturing method, the inner diameter of the cylindrical sleeve is determined with respect to the surface 24 of the iron core 20.

Next, the stator assembly 52 is
Fixed to FIG. 11 shows this stator 52 of the base 60.
2 shows a portion for fixing. The base 60 has a circular shape,
Rectangular holes 61 are arranged and opened. A hole 63 is formed at a position surrounded by these holes 61. Three cut and raised portions 62 are formed on the circumference of the hole 63. The stator 52 is placed on the base 60. The twelve winding portions 50 of the stator 52 correspond to the holes 61,
The hole 61 is a relief part of the winding part 50. When the stator 52 is placed in such a manner that the winding portion 50 and the hole 61 correspond to each other, the stator 5
The cut-and-raised portion 62 fits into the two three holes 26. That is, the cut-and-raised portions 62 are provided to determine the position of the stator 52 on the base. The base 60 and the stator 52 are positioned and fixed by outsert molding.

FIG. 12 shows the stator 54 thus obtained. The stator 54 is fixed on a base 60 and has a through hole 55 formed by a cylindrical sleeve 51 at the center. As in the first embodiment, an oil-impregnated bearing is press-fitted into this through hole 55, and the rotor is supported by this bearing.

[0024]

As described above, according to the present invention, the bearing press-fitting hole is formed of a soft resin having no oil absorption at the time of forming the insulating coating, or the cylindrical coating portion is formed on the inner surface of the bearing press-fitting hole by the hard resin molding. Thereby, when the oil-impregnated alloy bearing is press-fitted and fixed, the suction of oil by the hard resin can be stopped by the soft resin, or can be stopped only at the cylindrical coating portion, so that the metal sleeve around the oil-impregnated alloy bearing is also unnecessary. .

Further, since the bearing press-fitting holes are formed of a soft resin, there is little variation due to shrinkage of the inner diameter of the oil-impregnated alloy bearing due to press-fitting, and there is an effect that sizing becomes unnecessary.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

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

FIG. 3 is a cross-sectional view showing a small molded motor according to the present invention.

FIG. 4 is a perspective view showing a stator section according to the present invention.

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

FIG. 6 is a perspective view of an iron core of the present invention.

FIG. 7 is a top perspective view of a lower mold of a molding die according to the present invention.

FIG. 8 is a bottom perspective view of the upper mold of the molding die according to the present invention.

FIG. 9 is a sectional view showing a relationship between a molding die and an iron core according to the present invention.

FIG. 10 is a perspective view showing a state in which a winding is formed on the iron core of the present invention.

FIG. 11 is a perspective view showing a portion for fixing a stator to a base according to the present invention.

FIG. 12 is a perspective view showing a state in which the stator of the present invention is formed and fixed on a base.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oil-impregnated alloy bearing 1a Metal sleeve 2 Insulating coating 2a Cylindrical sleeve 3 Resin 3a Cylindrical coating part 4 Drive winding 5 Iron core 6 Bearing press-fitting hole 7 Output shaft 8 Rotor 9 Mounting structure part 20 Iron core 22 Magnetic pole 23 Projecting part 24 Magnetic force line generation Surface 25 Through hole 26 Hole 30 Lower die 31 Projection 32 Positioning surface 33 Groove 34 Depression 35 Lower surface 36 Depression 37 Smooth surface 40 Upper die 41 Projection 42 Hole 43 Depression 44 Smooth surface 45 Smooth surface 46 Smooth surface 50 Winding 51 Resin member 52 Stator assembly 54 Stator 60 Base 61 Hole 62 Cut and raised 63 Hole

Claims (2)

(57) [Claims] An insulating film for insulating between an iron core of a core type motor and a drive winding is formed of a soft first resin having little oil absorption, and the center of the iron core is formed when the insulating film is formed. A small molded motor wherein a cylindrical sleeve concentric with the iron core is formed at the same time in the first resin and an oil-impregnated alloy bearing is press-fitted into an inner hole of the cylindrical sleeve. Wherein the resin thin film is further formed on an inner surface of said cylindrical sleeve, according to claim 1, wherein said oil-impregnated alloy bearing hole consisting of the resin film inner surface is characterized by comprising press-fitted
The small-sized molded motor as described .