JPH11329881A - Manufacture of coil device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a coil against deformation caused by molding pressure without increasing the molding die cost. SOLUTION: The outer surface of a coil 12 wound on a bobbin 10 is covered with a reinforcing cylinder 19. The coil 12, the bobbin 10, and the reinforcing cylinder 19 are set in a secondary molding die 20, and molten molding material is injected into the molding die 20. At this point, a high molding pressure is locally applied to an injection space around the outer surface of the coil 12, but the coil 12 is covered with the reinforcing cylinder 19 which is hardly deformed, so that the coil 12 is prevented from being deformed by a molding pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a coil device.

[0002]

2. Description of the Related Art FIG. 5 shows a manufacturing process of a conventional coil device a disclosed in Japanese Patent Application Laid-Open No. 5-190348. At the time of manufacture, first, a resin-formed bobbin b
, A terminal fitting e is attached to a terminal attaching portion d projecting from the bobbin b, and a terminal of a lead wire f extending from the coil c is connected to the terminal fitting e. Next, this is set in a secondary molding die g, and a molding material is injected, whereby a cylindrical protective layer portion h surrounding the outer peripheral surface of the coil c and a connector portion surrounding the terminal mounting portion d. and i. At the time of secondary molding, as shown in FIG. 6, gates j are provided at a plurality of locations along the outer periphery of the coil c, and the molding material injected into the mold g from these gates j is the outer periphery of the coil c. And flows toward the terminal mounting portion d.

[0003]

Among the flow paths of the molding material, the path along the outer circumference of the coil c has a smooth arc shape, whereas the path from the coil c to the terminal mounting portion d is bent. As a result, the molding pressure is also increased, and there is a possibility that the coil is partially deformed into a chevron shape n as shown by a chain line in FIG. As a means for avoiding the deformation of the coil c, it is conceivable to increase the number of gates j to reduce the molding pressure of the secondary molding die g. In the present application, not only does the structure of g become complicated and the mold cost increases, but also the problem that the material cost increases due to an increase in the amount of the liner that is hardened and discarded in the gate j and increases. The present invention has been made in view of the above circumstances, and has as its object to prevent deformation of a coil due to molding pressure without increasing die cost.

[0004]

According to a first aspect of the present invention, there is provided a method of manufacturing a coil device in which a coil is set in a mold and a molding material is injected to form an insulating protective layer on the outer periphery of the coil. Prior to the injection of the molding material, the peripheral surface of the coil is covered with a reinforcing cylinder. According to a second aspect of the present invention, in the first aspect, the coil is fitted around an outer periphery of a bobbin, the reinforcing cylinder is attached so as to cover the outer periphery of the coil, and the bobbin is positioned in the mold. And set it.

According to a third aspect of the present invention, in the second aspect of the invention, the bobbin has a structure in which a terminal mounting portion is provided.
The terminal fitting attached to the terminal attaching portion and the lead wire extending from the coil are connected and set in the mold. According to a fourth aspect of the present invention, in the second or third aspect of the present invention, a pair of flange portions are formed on the outer periphery of the bobbin so as to sandwich the coil in the axial direction, and the reinforcing cylinder is further provided. Are fitted to the pair of flange portions.

[0006]

<Operation and effect of the invention><Invention of claim 1> Since the coil is covered with the reinforcing cylinder, deformation of the coil due to molding pressure can be prevented. In addition, since there is no fear of deformation of the coil, it is possible to increase the molding pressure, thereby reducing the number of gates and reducing the amount of liner that is hardened in the gates and wasted. <Invention of Claim 2> Since the coil is solidified in a state fitted to the bobbin and set in the mold, the positioning of the coil in the mold is ensured.

<Invention of Claim 3> Since the terminal fitting is fixed to the terminal mounting portion, the position of the terminal fitting in the mold is stabilized. <Invention of claim 4> Since the reinforcing cylinder is fitted around the flange portion, the reinforcing cylinder is restricted from floating with respect to the bobbin.
The coil is prevented from being deformed due to the radial movement of the reinforcing cylinder.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A first embodiment of the present invention will be described below with reference to FIGS. As shown in a cross section in FIG. 3, the coil device A has a cylindrical bobbin 10 having flanges 11 protruding at both ends, and a pair of flanges 11 on the outer periphery of the bobbin 10. The coil 12 fitted in a state sandwiched in the direction, and the terminal mounting portion 1 extending outward (upward in FIGS. 1 to 3) from one flange portion 11.
3, a terminal fitting 14 fixed to the terminal mounting portion 13,
A lead wire 15 extending from both ends of the coil 12 and connected to the terminal fittings 14, a resin protective layer 16 surrounding the coil 12, a terminal mounting portion 13, and a lead wire 15 surrounding the lead wire 15 along the same. It comprises a protrusion 17, a connector 18 surrounding the terminal fitting 14, and a reinforcing cylinder 19 covering the outer periphery of the coil 12.

Next, the manufacturing process of the coil device A will be described. First, in a primary forming step, the bobbin 10 and the terminal mounting portion 13 are integrally formed using a mold (not shown), the coil 12 is fitted around the bobbin 10, and the terminal fitting 14 is attached to the distal end of the terminal mounting portion 13. Are fixed, and the lead wire 15 extending from the coil 12 is connected to the terminal fitting 14 along the side surface of the terminal mounting portion 13. Then, the reinforcing cylinder 19 is attached to the bobbin 10. Here, the reinforcing cylinder 19 will be described. The reinforcing cylinder 19 is made of a material that is not easily deformed, such as a metal or a hard synthetic resin, and has a cylindrical shape. The inner diameter of the reinforcing cylinder 19 is the same as or slightly smaller than the outer diameter of the flange portion 11. The axial length of the reinforcing cylinder 19 is set to be longer than the axial length of the coil 12. The reinforcing cylinder 19 is externally fitted to the flange portion 11 from the left side in FIGS.
It is abutted against a stopper 11A formed on the right flange 11. The reinforcing cylinder 19 and the flange portion 11 may be fixed by an adhesive, or may be press-fitted and fixed by friction.

The reinforcing cylinder 19 attached to the bobbin 10 in this manner covers the entire outer periphery of the coil 12, and the coil 12 is shielded from the outside.
Thereafter, the bobbin 10 is set in the secondary molding die 20. The secondary molding die 20 includes a pair of a male die 21 and a female die 22. The male mold 21 is connected to the connector 18.
Has a cavity 21B for molding a connector portion for molding the same. One female mold 22 has a concentric circular protective layer molding cavity 22A spaced a predetermined distance from the outer periphery of the coil 12, and an extension molding surrounding the terminal mounting portion 13 at a predetermined spacing. Cavity 22B, a primary sprue 22C connected to the nozzle 23A of the injection cylinder 23,
A pair of secondary sprues 22D extending from the primary sprue 22C in an arc shape concentric with the coil 12, a tertiary sprue 22E extending concentrically inward from the tip of each secondary sprue 22D, and a protection from the tertiary sprue 22E. It has a plurality of gates 22F connected to the layer forming cavity 22A and a cylindrical positioning portion 22G fitted on the inner periphery of the bobbin 10 (see FIG. 4).

When the bobbin 10 is set in the secondary molding die 20, as shown in FIG.
The bobbin 10 and the coil 1
2 is positioned in the radial direction with respect to the female mold 22. In addition, the left end surface of the bobbin 10 abuts against the female mold 22 and the cover 13A fitted to the tip of the terminal mounting portion 13 abuts against the inner wall surface of the connector forming cavity 21B. Idling is regulated.
In this set state, a molten molding material is supplied from the injection cylinder 23 under a predetermined pressure into the protective layer molding cavity 22A through the sprues 22C, 22D, 22E and the gate 22F. The molding material supplied here passes through a cylindrical path between the inner wall surface of the protective layer portion forming cavity 22A and the reinforcing cylinder 19, and extends the extension portion forming cavity 22B and the connector portion forming cavity 21B.
B is supplied. Then, after the molding material is cured, the molds 21 and 22 are opened to obtain the coil device A shown in FIG.

The flow path of the injected molding material has a cylindrical shape in the protective layer portion forming cavity 22A, so that it can flow relatively smoothly.
Since the path from A to the extension molding cavity 22B is bent at substantially a right angle, the fluidity deteriorates. As a result, a high molding pressure acts on the portion near the extension molding cavity 22B. However, since the coil 12 is covered over the entire circumference by the hardly deformable reinforcing cylinder 19, the molding pressure does not reach the coil 12, and even if the molding pressure is high, the coil 12 is deformed due to it. Never. Therefore, the thickness of the protective layer 16 surrounding the coil 12 becomes uniform over the entire circumference.

As described above, in the present embodiment, the coil 12 is covered with the reinforcing cylinder 19 before the secondary molding, so that the molding pressure does not act on the outer periphery of the coil 12. 12 can be prevented from being deformed. Also, by preventing deformation of the coil 12,
It is also possible to increase the molding pressure, so that the gate 22
It is possible to reduce the number of F. This gate 2
Reducing the number of 2F means reducing the cost of the mold by simplifying the shape of the female mold 22. In addition, the molding material which is hardened in the gate 22F after molding and discarded wastefully is reduced. Since it means that the amount is reduced, the material cost can be reduced. Further, since the reinforcing cylinder 19 is externally fitted to the flange portion 11, the reinforcing cylinder 19 is
, The reinforcing cylinder 19 does not press the outer periphery of the coil 12 to cause the coil 12 to be deformed. The coil 12 to be solidified is the bobbin 1
Since the coil 12 is solidified while being wound around zero, the coil 12 can be reliably positioned in the secondary molding die 20. Further, since the terminal fitting 14 is formed on the bobbin 10 and the terminal fitting 14 is fixed thereto, the terminal fitting 14 can be reliably positioned in the secondary molding die 20.

<Other Embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings. For example, the following embodiments are also included in the technical scope of the present invention. In addition, various changes can be made without departing from the scope of the invention. (1) In the above embodiment, the secondary molding is performed with the coil fitted in the bobbin. However, according to the present invention, only the coil and the reinforcing cylinder are set in the secondary molding die without using the bobbin. May be. (2) In the above embodiment, the terminal mounting portion is provided on the bobbin, and the terminal fitting is fixed thereto. However, according to the present invention, a bobbin without the terminal mounting portion can be used. (3) In the above embodiment, the reinforcing cylinder is externally fitted to the pair of flange portions formed on the bobbin. However, according to the present invention, the reinforcing cylinder may be closely attached to the outer peripheral surface of the coil.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state before a reinforcing cylinder is attached to a bobbin in a first embodiment.

FIG. 2 is a cross-sectional view illustrating a state in which a bobbin is set in a mold according to the first embodiment.

FIG. 3 is a cross-sectional view of the coil device according to the first embodiment.

FIG. 4 is a front view of a mold according to the first embodiment.

FIG. 5 is a sectional view of a conventional coil device.

FIG. 6 is a front view showing a conventional mold.

[Explanation of symbols]

 A: Coil device 10: Bobbin 11: Flange part 12: Coil 13: Terminal mounting part 14: Terminal fittings 15: Lead wire 16: Protective layer part 19: Reinforcing cylinder 20: Mold for secondary molding

Claims (4)

[Claims] 1. A method of manufacturing a coil device, comprising setting a coil in a mold, injecting a molding material, and forming an insulating protective layer portion on the outer periphery of the coil, wherein the coil material is injected prior to the injection of the molding material. And a method of manufacturing a coil device, wherein a peripheral surface of the coil is covered with a reinforcing cylinder. 2. The method according to claim 1, wherein the coil is fitted around the outer periphery of a bobbin, the reinforcing cylinder is mounted so as to cover the outer periphery of the coil, and the bobbin is positioned and set in the mold. Item 2. A method for manufacturing a coil device according to Item 1. 3. A structure in which a terminal mounting portion is provided on the bobbin, and a terminal fitting mounted on the terminal mounting portion and a lead wire extending from the coil are connected and set in the mold. 3. The method for manufacturing a coil device according to claim 2, wherein: 4. A structure in which a pair of flange portions positioned so as to sandwich the coil in the axial direction is formed on the outer periphery of the bobbin, and the reinforcing cylinder is fitted externally to the pair of flange portions. The method for manufacturing a coil device according to claim 2 or 3, wherein: