JP7247847B2 - REACTOR MANUFACTURING METHOD AND REACTOR MANUFACTURING MOLD - Google Patents

Description

The technology disclosed in the present specification is a method for manufacturing a reactor in which an assembly of a coil molded body in which a coil is covered with a resin and a magnetic core is covered with a resin cover, and a reactor suitable for manufacturing such a reactor. Regarding molds.

A reactor is known in which a core is assembled to a coil and the assembly of the coil and the core is covered with resin. Patent Literature 1 discloses an example of a method for manufacturing such a reactor. Patent Literature 1 discloses a method of manufacturing a reactor in which a pair of coils are attached to a ring-shaped core. The manufacturing method comprises two molding steps. In the first molding process (primary molding process), a structure in which a part of the core (inner core) is placed inside each of the pair of coils is placed in a mold, and the inner core and the coil are covered with resin to mold the coil. shape the body. In the second molding process (secondary molding process), the assembly in which the outer core that magnetically connects the ends of the pair of inner cores is assembled with the coil molded body is placed in another mold, and a resin cover that covers the assembly is placed. to mold.

As in the primary/secondary molding process of Patent Document 1, molding a resin mold so as to cover a part of the part after placing the part in the mold is called insert molding. For convenience of explanation, a part to be put into a mold is called an insert part. If the resin leaks into the gap between the mold and the insert part due to the dimensional variation of the insert part, it causes burrs. A movable mold in which a part of the mold is movable is sometimes used to fill the gap between the mold and the insert part (for example, Patent Document 2).

JP 2013-225688 A JP-A-2002-36296

In the case of the reactor, the tip of the lead wire of the coil is exposed and covered with resin from the middle. In some cases, the lead wires are partially covered with resin in a primary molding process, and a resin cover is formed in a secondary molding process. In the secondary molding process, a part whose lead wires are partially covered with resin is used as an insert part. In that case, there is a risk that a gap will occur between the insert part and the mold in the secondary molding process due to a dimensional error in the resin formed in the primary molding process (the resin in the part that partially covers the lead wires). If a movable mold is used to narrow the gap caused by the dimensional error, the cost increases. This specification provides a technique for suppressing the gap between the mold and the insert part (especially the gap at the boundary between the lead wire of the coil and the resin) without using a movable mold.

The reactor manufacturing method disclosed in this specification includes a primary molding process and a secondary molding process. In the primary molding step, a coil molded body in which the coil is covered with resin is molded. In the secondary molding process, the assembly in which the core is attached to the coil molded body is placed in a mold, and a resin cover that covers the core and is integrated with the coil molded body is molded. The coil mold body may cover a part of the coil. It should be noted that, of course, the lead wire of the coil is exposed from the resin of the coil mold body. The resin cover may cover the entire core, or may cover a portion of the core. In the manufacturing method disclosed in this specification, the coil molded body has a resin tapered portion that tapers toward the tip of the lead wire of the coil. A mold for the secondary molding step is provided with a tapered groove into which the tapered portion is fitted. The gap between the surface of the tapered portion and the inner surface of the tapered groove becomes smaller with respect to the dimensional error of the tapered portion in the extending direction of the lead wire. Therefore, the gap between the mold and the insert part in the secondary molding process (especially the gap at the boundary between the lead wire of the coil and the resin) can be suppressed without using a movable mold. The mold described above is also a novel technique disclosed in this specification.

It is desirable that the opening angle of the tapered groove is 90 degrees or less. The smaller the opening angle of the tapered groove, the smaller the gap between the surface of the tapered portion and the inner surface of the tapered groove with respect to the dimensional error of the tapered portion in the extending direction of the lead wire.

Details and further improvements of the technique disclosed in this specification are described in the following "Mode for Carrying Out the Invention".

It is a perspective view of a reactor. It is a perspective view of a coil mold body. FIG. 4 is an exploded perspective view of a coil mold body and a core; FIG. 4 is a perspective view of an assembly of a coil mold body and a core; FIG. 5 is a cross-sectional view of the assembly set in the mold (corresponding to the cross section along line VV in FIG. 4); FIG. 4 is a cross-sectional view of the assembly set in the mold (mold open);

First, the completed reactor 2 will be described. FIG. 1 shows a perspective view of the reactor 2. As shown in FIG. The reactor 2 includes a coil 11 formed by winding a rectangular wire into a rectangular tube shape, a core 20 surrounding the coil 11 and passing through the inside of the coil 11, and a resin cover 30 covering the coil 11 and the core 20. It has In FIG. 1, the core 20 is covered with the resin cover 30 and cannot be seen. The resin covering the coil 11 (coil protection portion 12) is formed prior to the molding of the resin cover 30, which will be described later in detail. A structure in which the coil 11 is covered with the coil protection portion 12 is called a coil mold body 10 . The coil protection portion 12 and the resin cover 30 are molded by insert molding.

The coil 11 is formed by edgewise winding a rectangular wire. The ends of the coil 11 are lead wires 11a and 11b. The lead wires 11a and 11b are exposed from the coil protection portion 12 in order to be connected to other electric parts. In other words, the coil protection portion 12 covers the lead wires 11a and 11b halfway. A portion of the coil protection portion 12 covering the lead wire 11a (11b) is a tapered portion 14a (14b) that tapers toward the tip of the lead wire 11a (11b). A resin wall 31 continues to the tapered portion 14a provided on the lead wire 11a.

The tapered portion 14 a is part of the coil protection portion 12 of the coil molded body 10 , while the resin wall 31 is part of the resin cover 30 . The coil protection portion 12 is made in a primary molding process, which will be described later, and the resin cover 30 is made in a secondary molding process, which will be described later. However, the coil protection part 12 and the resin cover 30 are made of the same resin material, and the coil protection part 12 and the resin cover 30 are integrated when the secondary molding process is completed.

A method for manufacturing the reactor 2 will be described below.

(Primary molding step) A coil molded body 10 in which the coil 11 is covered with a resin (coil protection portion 12) is molded. FIG. 2 shows a perspective view of the coil mold body 10. As shown in FIG. The coil 11 is formed by edgewise winding a rectangular wire, and has a rectangular tubular shape. The coil protector 12 partially covers the coil 11 and partially exposes the coil 11 . The coil protection portion 12 covers the corners of the sides of the rectangular cylindrical coil 11, the inside of the coil 11, and the coil end faces in the coil axial direction. In the coordinate system shown in the figure, the X direction corresponds to the coil axis direction. The direction of the X-axis corresponds to the coil axis direction in other drawings as well.

The coil 11 has two leads 11a, 11b, which correspond to the ends of the wound windings. The coil protection portion 12 covers the lead wires 11a and 11b halfway, and the tips of the lead wires 11a and 11b are exposed.

A tapered portion 14a (14b) that tapers toward the tip of the lead wire 11a (11b) is provided halfway along the lead wire 11a (11b). As described above, the winding wire of the coil 11 is a flat wire, and the tapered portion 14a (14b) extends the flat lead wire 11a (11b) from the normal direction of the narrow surface (the Z direction in the drawing). It's tapered when you look at it. The tapered portion 14a has a rectangular shape when viewed from the normal direction (the X direction in the figure) of the wide surface of the lead wire 11a. Similarly, the tapered portion 14b is rectangular when viewed from the direction normal to the wide surface of the lead wire 11b (the Y direction in the drawing).

(Assembly Process) The assembly process will be described with reference to FIGS. FIG. 3 is an exploded perspective view of the coil mold body 10 and the core 20. FIG. The core 20 is composed of a pair of E-shaped split cores 21 . FIG. 4 is a perspective view of an assembly 40 in which a pair of E-shaped split cores 21 are attached to the coil mold body 10. As shown in FIG. In the assembly process, a pair of E-shaped split cores 21 are attached to the coil molded body 10 to assemble an assembly 40 in which the cores 20 surround the coil molded body 10 and pass through the coil 11 .

The split core 21 has an E-shaped center beam 23 inserted inside the coil of the coil mold body 10 . The beams 22 on both sides of the E shape are located on the sides of the coil mold body 10 . The tips of the beams 22 on both sides of the two split cores 21 face each other, and the portion of the core 20 excluding the beam 23 in the center surrounds the coil mold body 10 in an annular shape.

The tapered portions 14a and 14b covering the lead wires 11a and 11b halfway are formed together with the coil protection portion 12 in the primary molding process, but the resin wall 31 shown in FIG. 1 is formed in the subsequent secondary molding process. be.

(Secondary Molding Process) The assembly 40 is placed in a mold 50 (see FIG. 5) to mold a resin cover 30 (see FIG. 1) that covers the core 20 and is integrated with the coil molded body 10 . That is, the resin cover 30 is also made by insert molding in which the assembly 40 is placed in a mold 50 and molten resin is injected.

FIG. 5 shows a cross-sectional view of the assembly 40 set in the mold 50. As shown in FIG. FIG. 5 corresponds to a cross section around the tapered portion 14a of the assembly 40 taken along line VV in FIG. A mold 50 is divided into a first mold 51 and a second mold 52 . After the assembly 40 is set in the second mold 52, the first mold 51 is combined and the mold 50 is closed. FIG. 6 shows a cross section of the mold 50 when it is opened. The first mold 51 is provided with a groove 53 into which the exposed portion of the lead wire 11a is inserted, and a tapered groove 54 that fits into the tapered portion 14a.

5 in which the mold 50 is closed, the cavity CA surrounded by the first mold 51 and the second mold 52 corresponds to the resin wall 31 shown in FIG. That is, when the resin cover 30 is formed by injecting molten resin into the mold 50 , the portion formed by the cavity CA becomes the resin wall 31 . The resin wall 31 is formed so as to cover the base of the tapered portion 14a of the coil mold body 10. As shown in FIG.

5 and 6 are diagrams of the lead wire 11a, which is a rectangular wire, viewed from the normal direction of the narrow surface thereof. As described above, the tapered portion 14a tapers toward the tip of the lead wire 11a when viewed from the normal direction (Z direction) of the narrow surface of the lead wire 11a. The first mold 51 is provided with a tapered groove 54 into which the tapered portion 14a is fitted. The inner side surface of the tapered groove 54 is parallel to the side surface of the tapered portion 14a. The opening angle A1 of the tapered portion 14a is preferably 90 degrees or less. Since the tapered portion 14a is tapered, the minimum value of the opening angle A1 is greater than zero.

The opening angle A1 of the tapered groove 54 provided in the first mold 51 is equal to the opening angle A2 of the tapered portion 14a.

The action of the tapered portion 14a and the tapered groove 54 will be described. An enlarged view of the gap G between the tapered portion 14a and the tapered groove 54 is shown at the bottom of FIG. A length L1 indicates the length of the gap G along the Y direction in the drawing. The Y direction in the drawing corresponds to the extending direction of the lead wire 11a. On the other hand, the length L2 indicates the width of the gap G. As shown in FIG.

If the coil protection portion 12 has a dimensional error, the size of the gap G changes. If the gap G becomes large, the molten resin injected into the cavity CA enters the gap G, causing burrs. However, the width of the gap G between the tapered portion 14a and the tapered groove 54 is the length L2 in the direction perpendicular to the tapered surface. Even if the size of the tapered portion 14a changes in the extending direction of the lead wire 11a (that is, even if the length L1 changes) due to a dimensional error, the width (length L2) of the gap G is affected. is small. Therefore, the width (length L2) of the gap G between the tapered portion 14a and the tapered groove 54 is less susceptible to variations in the size of the tapered portion 14a. The manufacturing method of the embodiment can reduce the gap between the mold 50 and the insert part in the secondary molding process (especially the gap at the boundary between the lead wire 11a of the coil and the tapered portion 14a of the resin).

In particular, when the opening angles A1 and A2 between the tapered portion 14a and the tapered groove 54 are 90 degrees or less, the influence of variations in the size of the tapered portion 14a on the width (length L2) of the gap G can be effectively suppressed. can be done.

5 and 6 show the structure around the tapered portion 14a. The structure around the tapered portion 14b is also the same as in FIGS.

The mold 50 has the following features. Mold 50 (first mold 51, second mold 52) has coil mold body 10 covered with resin (coil protection portion 12) and assembly 40 of core 20 covered with resin cover 30. A mold for manufacturing the reactor 2 . The coil molded body 10 has a resin tapered portion 14a (14b) that tapers toward the tip of the lead wire 11a (11b) of the coil 11 . The first mold 51 is provided with a tapered groove 54 into which the tapered portion 14a (14b) is fitted. The opening angle A1 of the tapered groove 54 is preferably 90 degrees or less.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or in the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims as of the filing. In addition, the techniques exemplified in this specification or drawings can simultaneously achieve a plurality of purposes, and achieving one of them has technical utility in itself.

2: Reactor 10: Coil mold body 11: Coil 11a, 11b: Lead wire 12: Coil protection part 14a, 14b: Taper part 20: Core 21: Split core 30: Resin cover 31: Resin wall 40: Assembly 50: Mold 51: First mold 52: Second mold 53: Groove 54: Tapered groove

Claims (4)

a primary molding step of molding a coil molded body in which the coil is covered with resin;
a secondary molding step of placing an assembly in which a core is attached to the coil molded body in a mold, and molding a resin cover that covers the core and is integrated with the coil molded body;
and
The coil molded body has a resin tapered portion that tapers toward the tip of the lead wire of the coil,
The mold is provided with a tapered groove in which the tapered portion is fitted,
A manufacturing method of a reactor. 2. The manufacturing method according to claim 1, wherein the taper groove has an opening angle of 90 degrees or less. A mold for manufacturing a reactor in which an assembly of a coil molded body in which a coil is covered with resin and a core is covered with a resin cover,
The coil molded body has a resin tapered portion that tapers toward the tip of the lead wire of the coil,
A mold for manufacturing a reactor, wherein the mold is provided with a tapered groove into which the tapered portion is fitted. The mold according to claim 3, wherein the taper groove has an opening angle of 90 degrees or less.

Images