JPH0378453A - Manufacture of armature for flat motor and device employing flat motor - Google Patents

Abstract

PURPOSE:To eliminate weld line by flowing fused resin material, ejected through a limit gate, by means of an annular protrusion arranged on one of upper or lower mold when an armature coil is molded with resin. CONSTITUTION:Fused resin material is ejected through a limit gate 27, arranged on a lower mold 20, into a cavity 19 formed of upper and lower molds 21, 20 and mounting an armature coil 9 thus forming an armature. Fused resin material, ejected through the limit gate 27, is temporarily filled in an ejection chamber 36 arranged on the lower mold 20 around a rotary shaft 6 at the inside of an annular protrusion 34a located closely to the armature coil 9, and subsequently the fused resin material is fed radially toward the armature coil 9 thus forming the armature. Since the fused resin material is temporarily filled, while being mixed, in the ejection chamber formed of annular protrusion and subsequently fed radially toward the armature coil, weld line can be eliminated when the armature coil is molded with resin.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Industrial Application Field) The present invention provides a method for preventing the generation of weld lines due to the flow state of molten resin material when injection molding an armature for a flat motor. The present invention relates to a method of manufacturing a flat motor armature and an apparatus thereof.

(Prior Art) A flat motor 1 is used to drive a cooling fan of an automobile radiator or a blower fan installed in an intake unit of an automobile air conditioner. As shown in FIG. 2, it has a closed casing 4 formed by combining a first bracket 2 and a second bracket 3. Each of the brackets 2.
A rotating shaft 6 is pivotally supported via an oil-impregnated bearing 5 supported by the armature 3, and the inner end of the rotating shaft 6 and the hub portion 7a of the armature 7 are fitted through serrations. A permanent magnet 8 is provided on the inner surface of the second bracket 3 with an undetermined gap between it and the armature 7, and the magnetic field formed between the permanent magnet 8 and the casing 4 is cut off. 7 is designed to rotate.

This armature 7 is constructed by molding an armature coil 9 consisting of a large number of single coils C almost entirely with synthetic resin to form a flat rotating body, and a connecting wire e protruding from the center is connected to a commutator 10. are doing. Further, a power feeding brush 11 is in sliding contact with the outer circumferential surface of the commutator 10 under the elastic force of a coil spring 13 built into the receiving portion 12 .

As shown in FIG. 5, the single coil C is formed by winding a copper wire 14 of a predetermined diameter into an annular shape to form a substantially trapezoidal shape. The armature coil 9 is formed by arranging the single coils C around the commutator 10 in an annular and overlapping manner, shifted by a predetermined pitch.

As shown in an enlarged view in FIG. 6, the commutator 10 is constructed by arranging the segments S on which the brushes 11 slide in a ring shape using a jig or the like and then integrating them with a thermosetting resin 15. As the thermosetting resin 15, phenolic resin is generally used. Further, a through hole 32 into which the rotating shaft 6 is fitted is formed in the thick cylindrical resin base 31 . Each segment S has a hook portion 16 to which the terminal e of the single coil C is connected, and a claw portion 17 that bites into the resin 15. After punching out a plate of copper or copper alloy, the hook portion 16 and the claw portion 17 are bent. Note that the reference numeral "33" in the figure indicates a metal sleeve fitted onto the rotating shaft 6.

Next, a method for manufacturing the armature 7 and its apparatus will be outlined based on FIG. 7.

This amateur 7 has a pre-formed commutator 1
0 and the armature coil 9 connected to the commutator 10 via the connecting wire e are installed in an injection molding device 18 and molded by the injection molding method (Utility Model No. 62-
(See Publication No. 40,044, etc.).

The injection molding device 18 has a lower mold 20 and an upper mold 21 that form a cavity 19 corresponding to the outer shape of the armature 7. A hole 22 is formed in the lower mold 2o for a commutator receiver into which the commutator 10 is fitted. Further, a sprue bush 24 is attached to the upper mold 21 in a replaceable manner, and the sprue bush 24 includes a sprue 26 for introducing molten resin material into the mold from a nozzle 25 of the molding machine, and A gate 27 is formed for injecting material into the cavity 19. Note that the symbol r28J in the figure is a bin for aligning the upper and lower molds 21 and 20.

When molding the amateur coil 9, first, each connecting wire e of the amateur coil 9 is connected to the hook portion 16 of the commutator 10 that has been molded in advance.

Next, the commutator 10 inserts these into the receiving hole 22.
Place it on the lower mold 20 so that it fits. Next, the lower mold 20 and the upper mold 21 are aligned by pins 28 and clamped, and then the molten thermoplastic resin 29 is passed through the nozzle 25 → sprue 26 → gate 27 of the molding machine into the cavity 19. eject into. Then, in this mold-clamped state, when the thermoplastic resin 29 is cooled and solidified for a predetermined period of time,
The armature coil 9 is covered with resin 29 in a flat shape, so that the armature coil 9 and the commutator 10 are integrated.

(Problems to be Solved by the Invention) The gate 27 in such an injection molding device 18 faces the cavity 19 and is an injection port for the molten resin material, so it is an important point that greatly affects the quality and productivity of the molded product. That's the part. In addition, it is better for the gate 27 to have as little flow resistance as possible while the molten resin material is flowing into the cavity 19. On the other hand, after the inside of the cavity 19 is filled, the gate 27 should be cooled and solidified as soon as possible. It is required to contain the resin. Furthermore, finishing after gate trimming of the molded product taken out from the mold 20 and 21 is easy.
It is also important that it is not noticeable after that. in this way,
The size and shape of the gate 27 are determined by finding a suitable compromise between two contradictory requirements, and are generally classified into restrictive gates and non-restrictive gates based on their shapes.

As is well known, the former type of restriction gate is one whose cross-sectional area is limited to an extent that enables rapid solidification of the gate, and standard gates are often used as this type of restriction gate. The amateur 7
The case of molding will be explained.

In this case, as shown in FIG. 8, if the position facing the standard gate is indicated by a broken line circle, multiple flows of molten resin material (arrows in the figure) are occurring within the cavity 19, and each flow tip is When the welds are not completely fused, a long and narrow weld line 30 is generated at the merged and welded portion, which is visually noticeable.

Furthermore, as shown by the arrows in FIG. 6, when the resin 29 is cooled and solidified, the resin 29 near the rotating shaft 6 generally points outward in the radial direction, and the resin 29 on the outer periphery points toward the rotating shaft 6. It's shrinking. Furthermore, the cooling rate at the surface of the armature 7 and the cooling rate at the periphery of the armature coil 9 are different, and the difference in cooling rate is particularly noticeable in the thick hub portion 7a. Therefore, since the resin 29 has a different heat shrinkage rate at each location, the strength is significantly reduced at the weld line 30, and cracks may occur at this location.

Since the occurrence of such a weld line 30 cannot be avoided when there are two or more gates 27, it is conceivable to provide the standard gate at only one location.
Even with this configuration, since the armature 7 itself is disk-shaped, two or more flows of the molten resin material inevitably occur, and weld lines 30 cannot be prevented.

Also, in the above publication (Utility Model Application Publication No. 62-40.044),
Forming a broken annular protrusion into a mold is disclosed. However, although this broken annular protrusion is an effective means for forming a resin flow path, it is not sufficient for preventing the weld line 30 and increasing the strength at the site.

On the other hand, when the armature 7 is injection molded using the latter non-restrictive gate 27 such as a film gate, ring gate, or disk gate, the molten resin material flows radially from the non-restrictive gate in the cavity 19.
The weld line 30 can be prevented from occurring. However, these non-restrictive gates have a problem in that their mold costs are high due to their complicated shapes. Moreover, when separating the upper and lower molds 20.21,
This has the disadvantage that a large annular gap is formed, making it difficult to finish the gate after trimming it, compared to the case of a standard gate.

By the way, as shown in FIG. 7, when the gate 27 is injection molded as the standard gate, the portion H (cross hatched portion in the figure) of the cavity 19 corresponding to the hub portion 7a of the armature 7 is temporarily filled with molten resin. Gather the materials and
It is also conceivable that when this portion H is filled with resin, the resin flows radially so as to overflow. However, since the amateur coil 9 shown on the flat surface in the figure is a plurality of single coils C arranged in an annular and superimposed manner, even if the formed amateur coil 9 is flattened by pressure, the surface When viewed microscopically, there are steps and gaps between each single coil C, and the surface is never flat. Therefore, in reality, the molten resin material injected toward the portion H flows through the steps on both sides of the amateur coil 9 or from flowing in the circumferential direction along the outer periphery of the commutator 10 from the portion H. The molten resin material flows radially outward along the gap faster, and the molten resin material flows irregularly along the armature coil 9. Therefore, even if the portion H exists in the cavity 19, the molten resin material does not flow radially so as to overflow after once accumulating in the portion H, and the weld line 3
It was not possible to prevent the occurrence of zero.

Furthermore, even if the injection molding apparatus is an injection molding apparatus in which the gate 27 is provided on the lower mold 20, or an injection molding apparatus in which the commutator 10 is located on the upper mold 21 side and the gate 27 is provided on the upper mold 21 or the lower mold 20, Similar to the injection molding apparatus 18 described above, the occurrence of weld lines 30 could not be prevented.

The present invention has been made to solve the above-mentioned problems of the prior art, and the first object is to inject the molten resin material in a radial direction when injection molding an armature for a flat motor by injecting the molten resin material from a restriction gate. It is an object of the present invention to provide a method for manufacturing an armature for a flat motor, which can prevent the generation of weld lines by causing the fluid to flow.

A second object of the present invention is to provide an apparatus for injection molding an armature for a flat motor, which uses a restriction gate that has a simple mold structure and is easy to post-finish, while allowing the molten resin material to flow radially to form a weld. An object of the present invention is to provide a manufacturing device for a flat motor armature that can prevent lines from forming.

[Structure of the Invention] (Means for Solving the Problems) The present invention for achieving the above-mentioned first object is characterized in that a plurality of single coils are arranged annularly and in a superimposed manner in a plane orthogonal to the rotation axis. placing an armature coil in a cavity formed by at least an upper mold and a lower mold, injecting molten resin material into the cavity from a restriction gate provided in either of the upper and lower molds and serving as an injection port; When injection molding an armature corresponding to the shape of the cavity, from the restriction gate to the space inside the annular protrusion provided on at least one of the upper and lower molds and close to the armature coil around the rotation axis. Injecting the armature by injecting a molten resin material and once filling the space with the injected molten resin material, flowing the injected molten resin material radially outward from the space in the radial direction of the armature coil. This is a method of manufacturing an armature for a flat motor, which is characterized by molding.

In order to achieve the second object of item 2, the present invention has a plurality of armature coils in which a plurality of single coils are arranged annularly and superimposedly on a plane perpendicular to the rotation axis, with a small number (both upper and lower). An armature corresponding to the shape of the cavity is placed in a cavity formed by the lower mold, and into this cavity, a molten resin material is injected from a restriction gate provided in either of the upper and lower molds and serves as an injection port. In a manufacturing apparatus for a flat motor armature for injection molding, an annular protrusion close to the armature coil and centered on the rotating shaft is formed on at least one of the upper and lower dies, and a position closer to the rotating shaft than the annular protrusion is formed on at least one of the upper and lower molds. This is an apparatus for manufacturing an armature for a flat motor, characterized in that the restriction gate is provided in the armature.

(Function) According to the manufacturing method described above, the molten resin material injected from the restriction gate into the space formed by the annular protrusion mixes in this space and once fills the space, and then from this space the diameter of the armature coil is Flows radially outward.

Therefore, the flow state within the cavity becomes uniform, and weld lines due to poor fusion at the flow tip do not occur.

Further, according to the manufacturing apparatus configured as described above, the molten resin material injected from the restriction gate to the inside of the annular projection is
While mixing within the space formed by the annular protrusion, it fills up,
Thereafter, it flows radially outward from this space in the radial direction of the armature coil. Therefore, the flow state within the cavity becomes uniform, and weld lines do not occur in the portion where the armature coil is resin-molded. Further, the annular projection forms an annular groove in the armature, and the heat of the molten resin material is also radiated from this groove.

(Example) Hereinafter, a method for manufacturing a flat motor armature and an apparatus thereof according to the present invention will be explained in detail based on the drawings.

FIG. 1 is a cross-sectional view showing the manufacturing process of the armature for a flat motor according to the present invention, and FIG. 2 is an enlarged cross-sectional view showing the main parts of the flat motor of the same embodiment. The same reference numerals are given to the same members, and some explanations thereof will be omitted.

The illustrated armature 7 for the flat motor 1 includes a P-molded commutator 10, and the commutator 10.
The armature coil 9 is connected to the armature coil 9 via a connecting wire e, and is installed in an injection molding device 18a, and is molded by injection molding.

The injection molding apparatus 18a has a lower mold 20 and an upper mold 21 that form a cavity 19 corresponding to the external shape of the armature 7, as shown in FIG. The upper die 21 has a hole 2 for a commutator receiver into which the commutator 10 is fitted.
2 is formed.

Further, a sprue bush 24 is replaceably attached to the lower mold 20, and a sprue bush 24 is attached to the sprue bush 24 for introducing molten resin material into the mold from a nozzle 25 of a molding machine (not shown). 26 and the molten resin material into cavity 1.
A gate 27 is formed which injects into the inside of the 9. As a resin material for molding the armature 7, thermoplastic resin such as PPS (polyphenylene sulfide) is generally used.

Furthermore, an annular projection 34a that is centered around the rotating shaft 6 and is unbreakable is formed on the lower mold 20, and this annular projection 3
An annular projection 34b having the same diameter as 4a is formed on the upper mold 21. Further, the gate 27 includes both annular projections 34a,
It is provided on the sprue bushing 24 so as to be located closer to the rotating shaft 6 than the sprue bushing 34b.

Therefore, as shown in FIG. 1.3, when the upper and lower molds 21 and 20 are clamped, both the annular protrusions 34a and 34b face each other with a small annular gap 35 interposed therebetween, and the cavity 1
An injection chamber 36 communicating with the gate 27 is defined in the interior of the injection chamber 9 . The armature coil 9 extends radially outward from the injection chamber 36 through the annular gap 35. In addition, in FIG. 3, the armature coil 9 is not shown.

In this way, the armature coil 9 is placed through the annular gap 35, and the clearance between the armature coil 9 and both annular protrusions 34a and 34b at this time is approximately 0.5 m.
It has been found through experiments that injection molding can be performed satisfactorily if the thickness is approximately m.

In particular, in this embodiment, the gate 27 is a standard gate that is often used as a restriction gate.
Three standard gates are provided in the injection molding apparatus 18a (only two gates are shown in FIG. 1).

The process of molding the armature 7 using the injection molding apparatus 18a configured in this way will be explained.

First, each connection wire e of the armature coil 9 is connected to the hook portion 16 of the commutator 10 pre-molded with a thermosetting resin 15, and these are placed on the lower mold 20.

Next, alignment is performed using the bin 28, and the lower mold 20 and the upper mold 21 are clamped.

Thereafter, the molten thermoplastic resin 29 is injected into the injection chamber 36 in the cavity 19 via the nozzle 25 → sprue 26 → gate 27 (standard gate) of the molding machine.

Then, in this mold-clamped state, when the thermoplastic resin 29 is cooled and solidified for a predetermined period of time, the armature coil 9 and the commutator 10 are integrated so that the armature coil 9 is covered with two resins in a flat shape. Ru. Note that the rotating shaft 6 is attached to the commutator 1 after molding the armature 7.
0 through hole 32.

In this case, as shown in FIG. 3, the molten resin material injected into the injection chamber 36 from the three gates 27 is
5 is substantially closed by the armature coil 9, the respective flows melt and mix within the injection chamber 36, and are temporarily stored. And the injection chamber 36
As the injection chamber 36 is filled with molten resin material, the molten resin material flows radially outward from the armature coil 9 through a small clearance.

At this time, since most of the portion of the cavity 19 corresponding to the hub portion 7a of the armature 7 is already filled with the molten resin material, the portion of the cavity 19 that corresponds to the hub portion 7a of the armature 7 is filled radially outward along the steps or gaps remaining on both sides of the armature coil 9. Even if the molten resin material flows in the opposite direction, the continuously injected molten resin material flows radially on both sides of the armature coil 9, which is flat as a whole. Therefore, according to the injection molding apparatus 18a described above, although the apparatus has a plurality of standard gates 27, the molten resin material can be made to flow radially within the cavity 19, and the generation of the weld line 30 can be prevented. It becomes possible.

In addition, as shown in Figure 2, the armature 7 after injection molding
An annular groove 37 formed by annular projections 34a and 34b is provided on both sides of the
a and 37b are formed to partition the hub portion 7a, which is a thick wall portion, from the outer peripheral portion, which is a thin wall portion. This annular groove 37
a and 37b, as shown by the arrow in the figure, can prevent the contraction of the hub part 7a, which has a high thermal contraction rate, from being transmitted to the outer peripheral part, and can also ensure a large heat dissipation area. It is possible to reduce shrinkage and improve heat dissipation, and it is possible to prevent cracks from forming in areas with weak strength.

Furthermore, the annular protrusions 34a and 34b can reduce the placement deviation of the armature coil 9, so that the thickness of the resin can be made uniform.

In addition, the standard gate has a simpler structure and lower mold cost than non-restricted gates such as film gates, so it is advantageous in terms of equipment and cost. Moreover, since it uses a standard gate, Amateur 7's gate 2
There is also an advantage that the resin flash produced at position 7 is relatively small and that the flash can be easily corrected.

In the illustrated embodiment, the annular projections 34a and 34b are provided on both the upper and lower molds 21.20, but the present invention is not limited to this case, and the armature 7 and the hub portion 7a are Depending on the shape or the position and shape of the armature coil 9, only one of the upper and lower molds 21 and 20 may be provided with an annular projection. Further, the present invention is not limited to the flat motor 1 in which the commutator 10 has a drum-shaped shape (it is also applicable to a flat motor in which the commutator is provided in a flat shape inside the armature 7).

[Effects of the Invention] As explained below, according to the method and device for manufacturing a flat motor armature according to the present invention, the annular protrusion allows the molten resin material injected from the restriction gate to be radially distributed within the cavity. This makes it possible to prevent weld lines from forming when molding armature coils with resin.

Furthermore, since an annular groove is formed in the armature by the annular protrusion, shrinkage of the resin can be reduced, heat dissipation can be improved, and cracks can be prevented.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the manufacturing process of a flat motor armature embodying the method and device for manufacturing an armature for a flat motor according to the present invention, and FIG. 2 shows the main parts of the flat motor of the same embodiment. The enlarged sectional view shown in FIG.
4 is a sectional view showing a flat motor used for boat fishing; FIG. 5 is a front view of a single coil constituting an amateur coil; and FIG. FIG. 7 is an enlarged sectional view showing the main parts of the figure, FIG. 7 is a sectional view showing the manufacturing process of a conventional armature for flat motor, and FIG.
FIG. 3 is a perspective view showing an armature of a flat motor. 1...Flat motor, 6...Rotating shaft, 7...
Amateur, 9...Amateur coil, 0...
・Commutator, 8.1.8 a... Injection molding device, 19... Cavity, 0... Lower mold, 21... Upper mold, 7.
... Gate (restriction gate), 0... Weld line, 34 a % b... Annular projection, 5... Annular gap, 36... Injection chamber (space), 7aSb... Annular groove, C ...single coil,
e...connection line, S...segment.

Claims (2)

[Claims] (1) A plurality of armature coils (9) in which a plurality of single coils (C) are arranged annularly and superimposedly on a plane perpendicular to the rotation axis (6) are installed at least in the upper die (21) and the lower die (20).
The molten resin material is placed in a cavity (19) formed by When injection molding an armature (7) corresponding to the shape of the cavity (19), the armature is provided on at least one of the upper and lower molds (20, 21) about the rotation axis (6). Coil (9)
The molten resin material is injected from the restriction gate (27) into the space (36) inside the annular protrusion (34a, 34b) adjacent to the molten resin material. The armature for a flat motor is characterized in that the armature (7) is injection molded by filling the armature (7) radially outward from the space (36) in the radial direction of the armature coil (9). Production method. (2) At least the upper die (21) and the lower die (20) are equipped with armature coils (9) in which a plurality of single coils (C) are arranged annularly and superimposedly in a plane orthogonal to the rotation axis (6).
The molten resin material is placed in a cavity (19) formed by In an apparatus for manufacturing an armature for a flat motor in which an armature (7) corresponding to the shape of the cavity (19) is injection molded, The annular projections (34a, 34b) are attached to the upper and lower molds (2
0, 21), and this annular projection (
34a, 34b), the restriction gate (27) is provided at a position closer to the rotating shaft (6).