JP2002050526A - Inductance element and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an inductance element thinner for preventing occurrence of cracks due to temperature change. SOLUTION: Winding wires 11, 12 are housed in an inner space 7 of cores 2, 3, which are paired. A central portion 6 is protruded on an inner surface 4A of one core 2, while a gap H is provided between an end surface 6A of this central portion 6 and an inner surface 3A of the other core 3. The inner space is filled with a filler 22 having hardening property. An adhesive tape 21 is bonded on the end surface 6A of the central portion 6. When the filler 22 shrinks due to temperature change, the adhesive tape 21 is peeled off. Accordingly, the end surface 6A will not be pulled in the direction of the inner surface of the other core 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an inductance element having a winding such as a transformer and a core, and a method of manufacturing the same.

[0002]

For example, as an inductance element such as a transformer used in a switching power supply, an EE type or EI type core is used, and a transformer using an EI type core is shown in FIG. A pair of upper and lower cores 10
A bobbin main body 104 is accommodated in an internal space 103 of the first and second 102, and a primary winding and a secondary winding are wound around the bobbin main body 104. A magnetic core 106 is provided at the center. The connection of the cores 101 and 102 is performed by a method of wrapping and fixing an adhesive tape around the cores 101 and 102, a method of fixing with a clamp, a method of bonding abutting portions of the cores 101 and 102, a method of bonding silicon or the like. There is a fixing method using an adhesive filler made of a resin such as epoxy.
The method of filling 07 has the advantage that the working time in assembling is reduced, and the finished product can diffuse the heat generated by the windings by the filler 107.

In the above-described transformer, it is preferable that the flat plate portion 105 be formed thin in order to reduce the thickness and weight. The dimensions of the magnetic core 106 are determined by the characteristics of the transformer, and a predetermined gap H is generated between the tip of the magnetic core 106 and the inner surface of the other core 102. Also, a gap h is generated between the bobbin main body 104 and the inner surface of the core 101 to fill the filler 107, and the gap H
And the dimensions of the gap h are different, and the gap H is generally larger than the gap h. In the transformer, the filler 107 absorbs the heat generated from the windings and dissipates heat.The heat expands the filler 107, and the filler 107 and the core 101 have different coefficients of thermal expansion. Since the intervals H and h are different, when the temperature rises, the filler 107 expands more in the interval H than in the interval h, and conversely, when the temperature decreases, the filler 107 expands in the interval H more than the interval h. The contraction is larger than that of the portion, so that the base 106 of the magnetic core 106 which is a corner is
When a force is applied to the portion A, and particularly when the flat plate portion 105 is formed to be thin, there is a problem that a crack having a V-shaped cross section is generated in the outer surface portion of the core 101 corresponding to the base 106A due to expansion and contraction of the filler 107. .

Therefore, the present invention solves the above problems,
An object of the present invention is to provide an inductance element which can be made thinner and can prevent occurrence of cracks due to a temperature change, and a method for manufacturing the same.

[0005]

According to a first aspect of the present invention, there is provided an inductance element in which a winding is housed in an inner space of a pair of cores, and a core is protruded from an inner surface of one of the cores. In an inductance element in which a gap is provided between the core and the inner surface of the other core and the internal space is filled with a curable filler, a partition member is disposed between the tip of the magnetic core and the filler. .

According to the above configuration, since the tip of the magnetic core and the filler are separated by the partition member, even if the filler shrinks due to a temperature change, the tip of the magnetic core may be pulled toward the inner surface of the other core. Further, generation of a force applied to one of the cores due to a temperature change can be suppressed.

[0007] The inductance element of claim 2 is
The partition member, from the adhesive force between the tip and the filler,
Adhesive force with the tip is small.

With the above structure, even if the filler between the leading end of the magnetic core and the inner surface of the other core contracts, if a tensile force larger than the adhesive force between the partition member and the leading end is applied, the partition member peels off from the leading end, No further tensile force is applied to the tip.

Further, the inductance element of claim 3 is
The partition member is an adhesive tape adhered to the tip.

According to the above configuration, before filling the filler,
The partition member can be provided simply by sticking the adhesive tape to the tip.

Further, in the inductance element according to a fourth aspect of the present invention, the cured filler is set so as to shrink at a temperature not higher than the maximum use temperature.

With the above structure, even when the temperature of the filler reaches the maximum use temperature, the filler does not generate a pressing force on the tip, and the deformation of the filler is always in the shrinking direction.

[0013] In a fifth aspect of the present invention, in the method for manufacturing an inductance element according to the second aspect, the filler is cured at a temperature higher than room temperature.

Conventionally, when the filler is cured at room temperature, the filler expands in accordance with the temperature difference between the room temperature and the maximum use temperature. The temperature difference from the temperature is small, and the amount of expansion of the filler can be reduced.

In a sixth aspect of the present invention, in the method for manufacturing an inductance element according to the second aspect, the filler is cured near a maximum temperature condition for use.

According to the above configuration, even when the temperature of the filler reaches the maximum use temperature, the filler does not generate a pressing force on the tip, and the deformation of the filler is always in the shrinking direction.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an inductance element according to the present invention will be described below with reference to the accompanying drawings. Figure 1
FIG. 2 shows an example in which the inductance element of the present invention is applied to a transformer. As shown in FIG. 2, the transformer 1 has a pair of cores 2 and 3 made of a magnetic material. The side wall portions 5 and 5 are integrally provided on the flat plate portion 4, and a central portion 6 serving as a magnetic core protrudes from the inner surface 4 </ b> A of the flat plate portion 4 at the center of the side wall portions 5 and 5. The core 3 is a flat plate, and an inner space 7 is formed between the cores 2 and 3 in a state where the side wall 5 is assembled with the inner surface 4A butted against the inner surface 4A. The bobbin main body 8 is housed in the inner space 7. You. The bobbin main body 8 integrally has flanges 10 and 10 on both sides of a cylindrical portion 9 and is formed of a synthetic resin or the like, and a primary winding 11 and a secondary winding 11 are formed on the outer surface of the cylindrical portion 9.
12 are wound coaxially, and the ends of the windings 11 and 12 are drawn out of the cores 2 and 3. An adhesive tape 21 serving as a partition member is adhered to the distal end surface 6A of the central portion 6, and a curable filler 22 is filled in the internal space 7 and cured. The adhesive tape
Reference numeral 21 has flexibility, for example, a resin tape having a thickness of about 1 mm and one surface of which has an adhesive surface 21A is used. As the filler 22, a material using a resin such as silicon or epoxy is used, and has an adhesive property. In addition, between the front end surface 6A of the center portion 6 and the inner surface 3A of the other core 3
The gap H is a gap h between the bobbin main body 8 and the inner surface 4A of the core 2. Further, the surface of the resin tape of the pressure-sensitive adhesive tape 21 (the other side of the pressure-sensitive adhesive surface) may be weakened by using a lubricant or the like so that the adhesive force with the filler 22 is reduced. It is set smaller than the adhesive strength between 6A and the filler 22. The partition member is not limited to the adhesive tape, and an adhesive may be applied to a sheet-like material to form the front end surface 6A.
In this case, the adhesive may be such that the adhesive force between the sheet-like material and the front end face 6A is equal to that of the front end face 6A and the filler.
Use a material that has a smaller adhesive strength with 22.

Next, the method of manufacturing the transformer 1 will be described mainly with respect to the process relating to the filler 22. The windings 11 and 12 are wound around the bobbin main body 8, respectively, and an adhesive tape is attached to the tip end surface 6A.
After attaching 21, the bobbin main body 8 is arranged in the internal space 7 to assemble the cores 2 and 3.
Inject. This pouring operation and subsequent curing are performed under a temperature condition higher than room temperature, preferably near the maximum use temperature condition of the filler 22, that is, the maximum temperature of the filler 22 when the transformer 1 is electrically driven. The highest temperature condition reached by the use of the filler 22, such as the maximum temperature of the filler 22 during transportation and storage, is the use maximum temperature condition. By controlling the temperature of the filler 22 during filling and during curing as described above, it is set so as to shrink under the maximum use temperature condition after curing.

Next, the operation of the above configuration will be described. For example, a filler when the transformer 1 is electrically driven
Explaining that the maximum temperature of 22 is the maximum use temperature,
Even if the filler 22 reaches the maximum use temperature due to the heat from the windings 11 and 12, etc., the filler 22 is hardened in advance near the maximum use temperature condition.
No force to press A is generated. On the other hand, when the transformer 1 is in an electrically non-driven state and the filler 22 becomes lower than the maximum use temperature,
Although the filler 22 in the gap H contracts, the adhesive tape 21 peels off from the front end face 6A, so that no tensile force is applied to the central portion 6. Therefore, the difference in the coefficient of thermal expansion between the cores 2 and 3 and the filler 22 and the gaps H and h prevent the occurrence of cracks at the portion corresponding to the root of the center 6 such as the outer surface of the core 2,
The thickness of the flat plate portion 4 of the core 2 can be reduced.

Next, a temperature T0 + t ° C higher than the normal temperature T0 ° C.
In addition, supplementing the case where the filling operation of the filler 22 and the subsequent curing are performed, the cured filler 22 has a maximum use temperature Tma.
Assuming that the temperature reached x ° C., assuming that the difference between the maximum use temperature Tmax ° C. and the normal temperature T0 ° C. is Ts ° C. (Tmax−T0), the filling operation of the filler 22 and the subsequent curing were performed at the high temperature T0 + t ° C. In the case, the temperature difference from the maximum use temperature Tmax ° C. becomes smaller by the amount of t ° C., whereby the maximum use temperature Tmax
Even when the temperature reaches ° C, the amount of expansion of the filler 22 in the gap H can be suppressed as compared with the conventional case. In this embodiment, the adhesive tape
Since a tape made of resin or the like is used for the base material of 21 and the base material is about 1 mm, preferably 1 mm or more, the contraction of the adhesive tape 21 in the thickness direction causes the filler 22 to expand due to the expansion of the filler 22. 6A can be suppressed. On the other hand, room temperature T0 ° C
And the filler 22 in the gap H shrinks, the adhesive tape 21
The effect can be suppressed by the action of.

According to the present invention, core cracks that occur in the production of thin transformers can be prevented beforehand.
By uniformly injecting the filler 21 into the internal space 7, the strength of the transformer can be improved, and the cores 2 and 3 can be made thin. In addition, there is no gap or gap between the cores 2 and 3 as compared with the conventional method. In addition, the work can be performed easily as compared with the conventional method of bonding the butted portions of the cores.

As described above, according to the first embodiment, the windings 11 and 12 are housed in the internal space 7 of the paired cores 2 and 3, and the core is located on the inner surface 4 A of the one core 2. A central portion 6 is protruded, a gap H is provided between a distal end surface 6A of the distal end of the central portion 6 and an inner surface 3A of the other core 3, and the internal space 7 is filled with a curable filler 22. In the inductance element, since the adhesive tape 21 serving as a partition member is disposed between the distal end surface 6A of the central portion 6 and the filler 22, the distal end surface 6A of the central portion 6 and the filler 22 are separated by the adhesive tape 21. Therefore, even if the filler 22 contracts due to a temperature change, the tip surface 6A is not pulled in the direction of the inner surface of the other core 3, and the generation of a force applied to one core 2 due to the temperature change can be suppressed.

Further, as described above, in the present embodiment, claim 2
Accordingly, the adhesive tape 21 as the partition member has a smaller adhesive force between the distal end surface 6A and the filler 22 than the adhesive force between the distal end surface 6A and the filler 22. Even when the filler 22 between the adhesive tape 3A and the adhesive tape 21 contracts, if a tensile force greater than the adhesive force between the adhesive tape 21 and the distal end face 6A is applied, the adhesive tape 21 is peeled off from the distal end face 6A.
No tensile force is applied to A.

Further, as described above, in the present embodiment, claim 3
Corresponding to the above, the partition member is an adhesive tape 21 adhered to the distal end surface 6A which is the distal end, and before the filler 22 is filled, the adhesive tape 22 is simply attached to the distal end surface 6A, and the distal end surface 6A and the filler 22 are filled. And a partition member can be provided therebetween.

Further, in this embodiment, according to the fourth aspect, the cured filler 22 is used at the maximum use temperature Tma.
Since it is set to shrink below x, filler 22
Even when the temperature reaches the maximum use temperature Tmax, the filler 22 does not generate a pressing force on the distal end surface 6A, and the deformation of the filler 22 is always in the contraction direction.

As described above, in the present embodiment, claim 5
According to the method for manufacturing an inductance element according to claim 2, since the filler 22 is cured under the condition of a temperature T0 + t higher than the normal temperature, conventionally, when the filler 22 is cured at the normal temperature, the normal temperature T0 and the maximum use temperature are used. Although the filler 22 expands in accordance with the temperature difference Ts from Tmax, the filler 22 is cured in advance under the condition of a temperature T0 + t higher than the normal temperature, so that the temperature difference from the maximum use temperature Tmax is small, and the expansion amount of the filler 22 is reduced. It can be kept small.

As described above, in this embodiment, claim 6
Accordingly, in the method of manufacturing an inductance element according to claim 2, since the filler 22 is hardened near the maximum use temperature Tmax condition, even if the filler 22 reaches the maximum use temperature Tmax, the tip of the filler 22 is increased. No force is exerted on the surface 6A.

Further, as an effect of the embodiment, by using a lubricant or the like on the surface of the resin tape of the pressure-sensitive adhesive tape 21, the adhesive force with the filler 22 is reduced, and the pressure-sensitive adhesive tape 21 as a partition member becomes a tip. Since the adhesive force between the tip 22 and the filler 22 is smaller than the adhesive force between the tip 6A and the filler 22, the tip 6A
The adhesive tape 21 and the filler 22 are peeled off when a tensile force greater than the adhesive force between the adhesive tape 21 and the filler 22 is applied even if the filler 22 between the adhesive tape 21 and the inner surface 3A of the other core 3 contracts. No further tensile force is applied to the tip surface 6A.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, in the embodiments, a transformer has been described as an example, but the present invention can be applied to various inductance elements. Further, the core is not limited to the EI type of the embodiment, and may be an EE type.
In this case, the tip surface of the other magnetic core becomes the inner surface of the other core.

[0030]

According to the first aspect of the present invention, in the inductance element, a winding is housed in an inner space of a pair of cores, a magnetic core is projected from an inner surface of one of the cores, and a tip of the magnetic core and the other of the cores. In the inductance element in which a gap is provided between the inner surface of the magnetic core and a filler having curability in the internal space, a partition member is disposed between the tip of the magnetic core and the filler. It is possible to provide an inductance element capable of preventing the occurrence of cracks due to a temperature change.

Further, the inductance element of claim 2 is
The partition member, from the adhesive force between the tip and the filler,
It is possible to provide an inductance element which has a small adhesive force with respect to the tip and can be made thinner and can prevent the occurrence of cracks due to a temperature change.

Further, the inductance element of claim 3 is
The partition member is an adhesive tape adhered to the tip, and can provide an inductance element that can be reduced in thickness and that can prevent the occurrence of cracks due to a temperature change.

Further, in the inductance element according to the present invention, the cured filler is set so as to shrink at a temperature not higher than the maximum temperature for use, and can be made thinner.
An inductance element capable of preventing the occurrence of cracks due to a temperature change can be provided.

According to a fifth aspect of the present invention, there is provided the method of manufacturing an inductance element according to the second aspect, wherein the filler is cured at a temperature higher than a normal temperature. It is possible to provide a method for manufacturing an inductance element capable of preventing occurrence of cracks.

According to a sixth aspect of the present invention, there is provided the method of manufacturing an inductance element according to the second aspect, wherein the filler is hardened near a maximum temperature condition for use. It is possible to provide a method for manufacturing an inductance element capable of preventing occurrence of cracks.

[Brief description of the drawings]

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

FIG. 2 is an exploded perspective view of the same.

FIG. 3 is a sectional view of a conventional example.

[Explanation of symbols]

 2 Core 3 Core 6 Central part (magnetic core) 6A Tip surface (tip) 7 Internal space 11 Primary winding (winding) 12 Secondary winding (winding) 21 Adhesive tape (partition member) 22 Filler

Claims (6)

[Claims] 1. A winding is accommodated in an inner space of a pair of cores, a magnetic core is protruded from an inner surface of one of the cores, and a gap is formed between a tip of the magnetic core and an inner surface of the other core. An inductance element, wherein a partition member is disposed between a tip of the magnetic core and the filler, wherein the partition element is provided with a filler having curability in the internal space. 2. The inductance element according to claim 1, wherein the partition member has a smaller adhesive force between the tip and the filler than the adhesive between the tip and the filler. 3. The inductance element according to claim 1, wherein the partition member is an adhesive tape adhered to the tip. 4. The inductance element according to claim 2, wherein the hardened filler is set so as to shrink at a temperature not higher than a maximum use temperature. 5. The method of manufacturing an inductance element according to claim 2, wherein the filler is cured at a temperature higher than room temperature. 6. The method for manufacturing an inductance element according to claim 2, wherein the filler is cured near a maximum temperature condition for use.