JPH0851032A - Coil and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a coil in which the inductance can be adjusted accurately and inexpensively by arranging an insulating resin by a predetermined thickness at least at the joint of two core pieces in order to form a magnetic gap between the two core pieces. CONSTITUTION:An E-shaped core piece 1 is immersed into an insulating resin bath and applied with an insulating resin 2 over the entire surface thereof before being brought into semicured state through pre-baking. A thickness adjusting jig 10 provided with a protrusion 11 having height (t) is then pressed until the protrusion 11 abuts, at the forward end thereof, against a tight contact face 1a being bonded at the time of assembling a core. Consequently, the insulating resin 2 on the tight contact face 1a is deformed plastically into a resin film having a constant thickness (t). The jig 10 is then removed and the insulating resin 2 is cured through post-baking. Finally, a doughnut coil part 5, an I-shaped core piece 3, and the E-shaped core piece 1 are combined into a coil assembly 15. Consequently, inductance of the coil 15 can be adjusted easily and accurately by varying the height of protrusion 11 of the thickness adjusting jig 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil, particularly a coil used as a transformer or a filter, and a method for manufacturing the coil.

[0002]

2. Description of the Related Art A coil in which a plurality of core pieces are combined to form a core is known. As an example of this coil inductance adjustment method, an insulating gap sheet is placed between core pieces, and the gap between the two core pieces is adjusted by the thickness of this gap sheet to adjust the coil inductance. There is a way to do it. However, while this method has the advantage that the inductance can be adjusted with high precision, the gap sheet cut into small pieces according to the size of the core is expensive, and the handling of this gap sheet is complicated, and automatic coil assembly is performed. There was a problem that it hindered the

SUMMARY OF THE INVENTION An object of the present invention is to provide a coil whose inductance can be adjusted inexpensively and accurately and a method for manufacturing the coil.

[0004]

In order to solve the above problems, a coil according to the present invention is (a) a plurality of core pieces constituting a core, and (b) integrally attached to the core. (C) on at least one of the plurality of core pieces, on at least one of the plurality of core pieces, an insulative resin, which is in a molten, melted or powdered state, is to be joined at the time of assembly. It is characterized in that it is applied to form an insulating resin having a predetermined thickness and is joined to another core piece through this insulating resin. Here, as a material of the insulating resin, a silicon resin, an epoxy resin, a urethane resin, a phenol resin, an acrylic resin, or the like is used.

With the above structure, an insulating resin having a predetermined thickness is arranged at the joint portion of at least two core pieces, and the insulating resin forms a magnetic gap between the two core pieces. Therefore, by properly setting the thickness of the insulating resin, the inductance of the coil can be adjusted accurately. Further, the coil manufacturing method according to the present invention includes (d) an insulating resin in a molten or melted or powdered state in at least one of a plurality of core pieces constituting the core,
At least after applying to an adhesion surface to be joined at the time of assembly, forming an insulating resin having a predetermined thickness before or during assembly, and (e) inserting the core through the insulating resin. And a step of forming a core by joining with another core piece.

Further, in another coil manufacturing method according to the present invention, (f) at least one of the plurality of core pieces constituting the core is provided with an insulating resin in a molten or melted or powdered state, At least a step of applying to a contact surface to be joined at the time of assembly; and (g) until the core has a predetermined inductance after joining the core piece to another core piece through the insulating resin. And a step of reducing the thickness of the insulating resin to a predetermined thickness.

By the above method, the thickness of the insulating resin is easily adjusted, and the automatic assembly of the coil is promoted.

[0008]

Embodiments of the coil and the method for manufacturing the same according to the present invention will be described below with reference to the accompanying drawings. In each of the following examples, the core is composed of an E-shaped core piece and an I-shaped core piece. [First Embodiment, FIGS. 1 to 3] As shown in FIG. 1, the E-shaped core piece 1 is immersed in a molten insulating resin bath to form the core piece 1.
The insulating resin 2 is adhered to the entire surface of the resin relatively thickly. As the insulating resin 2, a silicone resin, an epoxy resin,
Urethane resin, phenol resin, acrylic resin, etc. are used. The insulating resin 2 is prebaked to be in a semi-cured state. However, the thickness of the insulating resin 2 may be adjusted by pressing the thickness adjusting jig 10 described below against the core piece 1 in the molten state.

Next, as shown in FIG. 2, the thickness adjusting jig 1
Press 0 against core piece 1. The thickness adjusting jig 10 includes a protrusion 11 having a height t, and is made of a material to which the insulating resin 2 is hard to adhere, such as Teflon. The value of t is set based on theoretical calculation or experimental results so that a coil having a desired inductance can be obtained. At this time, if the insulating resin 2 has a property of curing shrinkage and heat shrinkage during the main curing, a device such as a value of t including the shrinkage amount in advance is taken into consideration. The thickness adjusting jig 10 has a contact surface 1 to which the tips of the protrusions 11 are joined when the core is assembled.
It is pressed until it hits a. The insulating resin 2 on the contact surface 1a is plastically deformed to form a resin film having a constant thickness t.
After that, the thickness adjusting jig 10 is removed and post-baked to fully cure the insulating resin 2.

Next, as shown in FIG. 3, the coil 15 is assembled by combining the donut-shaped coil portion 5, the I-shaped core piece 3 and the E-shaped core piece 1. The doughnut-shaped coil portion 5 is formed by winding a polyurethane-coated copper wire into a donut shape or by stacking sheet coils. It is inserted. The I-shaped core piece 3 is made of the same material as the E-shaped core piece 1, and for example, a magnetic material such as ferrite is used. The I-shaped core piece 3 is placed on the contact surface 1a of the E-shaped core piece via the insulating resin 2 having a constant thickness t. After that, an insulating tape (not shown) is attached to the core pieces 1, 3
The core pieces 1 and 3 are firmly joined to each other by wrapping them around or by applying an adhesive between the core pieces 1 and 3 and curing the same. In the core 4 composed of the core pieces 1 and 3, an insulating resin 2 having a thickness of t is arranged at a portion where the core pieces 1 and 3 are joined. A magnetic gap (the size of the magnetic gap is t) is formed. Then, the obtained coil 15 has a desired inductance.

Thus, the coil 15 has the thickness adjusting jig 10
By arbitrarily setting the height of the protrusion 11 so that a coil having a desired inductance can be obtained, the inductance can be adjusted accurately and easily. In the case of the first embodiment, the protrusion-shaped voids 7 are formed in the insulating resin 2, but this hardly affects the inductance adjustment of the coil.

Since the insulating resin 2 is also formed on the core surfaces 1c and 1d facing the coil portion 5, the insulating resin 2 is provided between the coil portion 5 and the core piece 1 which is a conductor. Sufficient electrical insulation will be ensured. As a result, the insulation distance between the coil portion 5 and the core piece 1 can be reduced, and the coil 15 can be downsized.

[Second Embodiment, FIGS. 4 to 6] As shown in FIG. 4, the E-shaped core piece 21 is immersed in a molten insulating resin bath to make the entire surface of the core piece 21 relatively thick. Insulating resin 2
2 is attached. After that, the insulating resin 22 is cured.
At this time, if the insulating resin 22 is a soft material, it is post-baked to bring the insulating resin 22 into a fully cured state, and if it is a hard material, it is pre-baked to have a semi-cured state.

Next, as shown in FIG. 5, the coil 35 is assembled by combining the donut-shaped coil portion 25, the I-shaped core piece 23 and the E-shaped core piece 21. In the coil portion 25, the middle leg portion 21b of the E-shaped core piece 21 is inserted into a hole 25a formed in the central portion thereof. The I-shaped core piece 23 is placed on the E-shaped core piece 21 via the insulating resin 22. An L meter 32 for measuring the inductance is electrically connected to the coil portion 25 with lead wires 33 and 34. Then, while measuring the inductance of the coil 35 with the L meter 32, the I-shaped core piece 23 is gradually pressed to reduce the thickness of the insulating resin 22 on the contact surface 21 a of the core piece 21. The inductance approaches a desired value as the insulating resin 22 becomes thinner. When the inductance reaches a desired value, pressurization of the I-shaped core piece 23 is stopped and insulating tape or the like (not shown) is wound around the core pieces 21 and 23 to keep the insulating resin 22 at a predetermined thickness. In this state, the core pieces 21 and 23 are firmly joined to form the core 24.

However, at this time, the thickness of the insulating resin 22 on the contact surface 21a may be directly monitored instead of the inductance. That is, while measuring the thickness of the insulating resin 22, the I-shaped core piece 23 is gradually pressed to reduce the thickness of the insulating resin 22, and when the predetermined thickness is reached, the core piece 23 is pressed. Stop and attach insulating tape to the core pieces 21, 23
Alternatively, the core pieces 21 and 23 may be firmly joined while the insulating resin 22 is kept at a predetermined thickness.

Thereafter, the coil portion 25 to the lead wire 33,
When 34 is removed and a hard material is used as the insulating resin 22, the insulating resin 22 is post-baked to be in a fully cured state. The coil 35 thus obtained has the same effect as the coil 15 of the first embodiment.

[Third Embodiment, FIG. 7] As shown in FIG.
The coil 40 includes an E-shaped core piece 41, an insulating resin 42, an I-shaped core piece 43, an insulating resin block 45, and a donut-shaped coil portion 50. The E-shaped core piece 41 is dipped in an insulating resin bath in a molten state, and the insulating resin 42 is attached to the entire surface of the core piece 41 with a relatively large thickness. After that, the insulating resin 42 is pre-baked to be in a semi-cured state.

Next, the coil portion 50, the E-shaped core piece 41 and the I-shaped core piece 43 are combined to assemble the coil 40. That is, the insulating resin block 45 is arranged on the insulating resin 42 on the contact surface 41 a of the core piece 41. The insulative resin block 45 may be embedded in the insulative resin 42 in advance before assembly. The insulative resin block 45 is formed in advance to a predetermined thickness t and post-baked to be in a fully cured state. The value of t is set based on theoretical calculation or experimental results so that a coil having a desired inductance can be obtained. The coil portion 50 has a hole 50 formed at the center thereof.
The middle leg portion 41b of the E-shaped core piece 41 is inserted through a.
The I-shaped core piece 43 is placed on the E-shaped core piece 41 via the insulating resin 42. The I-shaped core piece 43 is gradually pressed to reduce the thickness of the insulating resin 42 on the contact surface 41a of the core piece 41. The inductance approaches a desired value as the thickness of the insulating resin 42 decreases. The inductance reaches a desired value and the magnetic gap size is adjusted in a state where the core piece 43 hits the insulative resin block 45 and stops, that is, in a state in which the insulative resin 42 on the contact surface 41a becomes a resin film having a thickness t. It Insulating tape or the like (not shown) is used for the core piece 4
The core pieces 41 and 43 are firmly joined to each other to form the core 44 while the insulating resin 42 is kept to have a predetermined thickness t by being wound around 1, 43. After that, the insulating resin 42 is post-baked to be in a fully cured state.

The coil 40 thus obtained has the same effect as the coil 15 of the first embodiment.

[Other Embodiments] The coil and the method for manufacturing the same according to the present invention are not limited to the above embodiments, but can be variously modified within the scope of the invention.

The core is not limited to the combination of the E-shaped core piece and the I-shaped core piece. For example, a combination of E-shaped core pieces and E-shaped core pieces, a combination of C-shaped core pieces and C-shaped core pieces, and the like may be used. Further, the number of core pieces to which the insulating resin is applied is not limited to one, and the insulating resin may be applied to a plurality of core pieces. Further, the application portion does not have to be the entire surface of the core, and may be limited to only the contact surface to be bonded or only the core surface facing the contact surface and the coil portion.

Further, although the above-mentioned embodiment describes the case where the insulating resin in the molten state is used, the insulating resin in the molten state or the powder state may be used.

[0023]

As is apparent from the above description, according to the present invention, at least one of a plurality of core pieces is used at the time of assembling at least an insulating resin in a molten or melted or powdered state. Since it is applied to the contact surface to be bonded to the insulating resin with a predetermined thickness and bonded to another core piece through this insulating resin, this insulating resin is applied between the core pieces. Form a magnetic gap. Therefore, the inductance of the coil can be accurately adjusted by setting the thickness of the insulating resin appropriately.

Further, according to the present invention, in at least one of a plurality of core pieces constituting the core, an insulating resin in a molten, melted or powder state is joined at least during assembly. Since the insulating resin having a predetermined thickness is formed before or at the time of assembling after being applied to the contact surface, the magnetic gap size can be adjusted inexpensively and easily. Therefore, the inductance of the coil can be adjusted inexpensively and easily. Moreover, variations in the gap size can be suppressed to a small level.

Further, according to the present invention, after the core piece is joined to another core piece via the insulating resin, the thickness of the insulating resin is reduced to a predetermined value until the core has a predetermined inductance. Since it is thick, no special jig is required,
The inductance of the coil can be adjusted inexpensively and easily. Moreover, since the gap size is determined while directly measuring the inductance, it is possible to suppress variations in the inductance of the coil.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a coil and a manufacturing method thereof according to the present invention.

FIG. 2 is a cross-sectional view showing a step that follows FIG.

FIG. 3 is a cross-sectional view showing a step that follows FIG.

FIG. 4 is a sectional view showing a second embodiment of the coil and the method for manufacturing the same according to the present invention.

FIG. 5 is a cross-sectional view showing a step that follows FIG.

6 is a cross-sectional view showing a step that follows FIG.

FIG. 7 is a cross-sectional view showing a third embodiment of the coil and the manufacturing method thereof according to the present invention.

[Explanation of symbols]

 1, 21, 41 ... E-shaped core piece 1a, 21a, 41a ... Adhesive surface 2, 22, 42 ... Insulating resin 3, 23, 43 ... I-shaped core piece 4, 24, 44 ... Core 5, 25, 50 ... Coil part 10 ... Thickness adjusting jig 11 ... Protrusions 15, 35, 40 ... Coil 45 ... Insulating resin block

Claims (3)

[Claims] 1. A plurality of core pieces constituting a core, and a coil portion integrally attached to the core, wherein at least one of the plurality of core pieces is either melted or melted or powdered. The insulating resin in the state of (1) is applied to at least the contact surface to be joined at the time of assembly to form an insulating resin having a predetermined thickness, and is joined to another core piece through this insulating resin. That is, the coil. 2. At least one of a plurality of core pieces constituting the core is provided with an insulating resin in a molten, melted or powdered state on at least a contact surface to be joined at the time of assembly. After that, a step of forming an insulating resin having a predetermined thickness before or during assembly, and a step of joining the core piece with another core piece via the insulating resin to form a core, A method for manufacturing a coil, comprising: 3. In at least one of a plurality of core pieces constituting the core, an insulating resin in a molten, melted or powdered state is applied to at least a contact surface to be joined during assembly. And a step of joining the core piece to another core piece via the insulating resin, and then reducing the thickness of the insulating resin to a predetermined thickness until the core has a predetermined inductance. And a coil manufacturing method comprising: