JPH03192704A - Ferrite core - Google Patents

Abstract

PURPOSE:To lower the height of mounting, and to make it possible to obtain a ferrite core having high operating efficiency by a method wherein the width and the height of the core, the width of the center leg and external leg, the back depth, and the distance between the center leg and the external leg satisfy prescribed conditions. CONSTITUTION:When core width is (a), core height is (b), center leg width is (c), outer leg width is (d) back depth, is (e), and the distance between the center leg and the outer leg is (g), the conditions shown in the formula I separately mentioned are satisfied simultaneously. To be more precise, the core height, which satisfies the conditions of the formula I, is low, also even after a winding has been wound, the increase in height is small, and as surface area can be made larger, heat-radiating property of the core is excellent. Also, almost no partial magnetic saturation is generated inside the core, and the degree of heat generation is low. As a result, when the core is applied to a transformer and a choke coil, its mounting height can be suppressed, and a ferrite core having high operating efficiency can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a ferrite core used in transformers, choke coils, etc., and particularly relates to a thin EE type or EI type ferrite core.

<Conventional Technology> Ferrite cores are used in power transformers, choke coils, etc. of various electronic devices.

The core is usually implemented in various devices as an EE-type core, in which the legs of a pair of E-type cores are butted against each other, or as an EI-type core, in which an E-type core and a 1-type core are joined together.

In recent years, the miniaturization of these electronic devices has progressed, and as a result, there has been a strict requirement to reduce the mounting height of the core, and various proposals have been made to reduce the mounting height.

For example, in Utility Model Publication No. 61-20729, the central leg,
An E-shaped core for a small transformer is disclosed in which left and right legs and a yoke portion are integrally formed of ferrite material.

This E-type core is a core for a transformer that is assembled so that each leg extends horizontally, and by configuring the height of the center leg to be lower than the height of both left and right legs, when the coil (winding) is wound. The height of the middle leg of the device is suppressed, and the mounting height is reduced.

However, this core requires a mold with a special shape different from that of the conventional E-type core, so it is difficult to say that it is suitable for boat fishing.

Further, for example, Japanese Patent Publication No. 44-28828 discloses a so-called vertical core in which each leg is mounted so as to extend in the vertical direction. In the same publication, in the case of a vertically installed core, if only the mounting height of the core is suppressed,
Since it is not possible to obtain the optimum characteristics for applications such as transformers and choke coils, the optimum dimensional ratio of each part is determined based on the height of the core.

That is, in the same publication, the optimum dimensions of the magnetic core are generally determined by the inductance L of the coil and the DC resistance R6e.
Since it is obtained from the conditions that maximize the ratio L/R,c,
First, the height of the magnetic core is determined, and then the ratio of each part to the height of the magnetic core is theoretically calculated and limited so that the condition that L/R, e becomes maximum is satisfied.

With such a configuration, it is possible to obtain a vertically placed magnetic core that has desired electrical characteristics and has the smallest shape. Note that if L/R,c is maximum, the efficiency will be the highest when applied to a transformer or choke coil.

However, L and F+ac are not always constant. For example, L has temperature characteristics, and the core generates heat when used. As a result, L decreases due to the temperature increase during use, and the output decreases. Therefore, even if a core dimension that maximizes L/R,c is theoretically determined, it is not necessarily the optimal core dimension.

<Problems to be Solved by the Invention> The present invention has been made under these circumstances. When a ferrite core is applied to a transformer or choke coil, the mounting height can be suppressed, and the installation height can be reduced during use. The purpose is to provide a ferrite core with high efficiency.

Note that since a high-power core has a large cross-sectional area and volume, it is particularly difficult to keep the mounting height low.
In addition, since the high-power core generates a large amount of heat during use, the deviation from the theoretical value of L/R,c is large (also, the effective saturation magnetic flux density of the core decreases, making it easier to magnetically saturate). As a result, the efficiency decreases, making it impossible to obtain the desired output value as a transformer.

Therefore, it is an object of the present invention to achieve the above object, particularly in a high-power ferrite core.

As a result of repeated research, the present inventors found that the above object can be achieved when the dimensional ratio of each part is set within a predetermined range in a ferrite core, and the following (1) to (5) ) completed the present invention.

(1) The core has a middle leg and a pair of outer legs extending in the length direction, and a pair of back flesh parts connected to the middle leg and the pair of outer legs and extending in the core width direction; This is a ferrite core that is mounted so that the middle leg and the outer leg are almost parallel to the mounting board, and the width of the core is a, the height of the core is b, the width of the middle leg is c, and the outer leg is A ferrite core characterized in that it simultaneously satisfies the conditions shown in DJ below, (ii) and (iii), where the width is d, the width of the back flesh is e, and the distance between the middle leg and the outer leg is g.

(i) 2.3≦c / b≦6.0 (ii) 0.4≦d / c≦0.7 0.4≦e / c≦0.7 (iii) 8.0≦a/g≦ 30 (2) It has a middle leg and a pair of outer legs that extend in the length direction of the core, and has a pair of back flesh parts that are connected to the middle leg and the pair of outer legs and extend in the width direction of the core, A ferrite core is used that is mounted so that the middle leg and the outer leg are substantially parallel to the mounting board, and the width of the core is a, the height of the core is b, the width of the middle leg is c, and the outer leg is When the width of is d, the width of the back flesh is e, the distance between the middle and outer legs is g, and the length of the middle leg is β, the following (if), (iii)
A ferrite core characterized in that it simultaneously satisfies the conditions shown in (iv) and (v).

(ii) 0.4≦d/c≦0,7 0.4≦e/C≦0.7 (iii) 8. 0≦a/g≦30 (3) The ferrite core according to (2) above, which satisfies the following condition (i).

(i) 2.3≦c / b≦6.0 (4) The above (1) or 3 that satisfies the following condition (vi)
ferrite core described in any of ).

(vi) c X b ≧ 50 mm 2 (5) The ferrite core according to any one of (1) to 4) above, which satisfies the following condition (vii).

(vii) 4. 0≦β/g≦40 Effect> The ferrite core of the present invention is mounted so that the legs are substantially parallel to the mounting substrate. In addition, such a core,
In this specification, it is referred to as a horizontally placed core.

Since the ferrite core of the present invention is a horizontally placed core that satisfies the above condition (i), it has an extremely low height, and
Since the above condition (iii) is satisfied, the increase in height is small even after the wire is wound.

According to the above condition (i), the surface area can be increased compared to a conventional core in which the cross-sectional area of the middle leg is the same, so that heat dissipation is good. In addition, the above condition (ii
), so there is almost no local magnetic saturation within the core and less heat is generated.

Therefore, the above conditions (i), (ii) and (iii)
), the ferrite core has a low mounting height (
Moreover, since the temperature rise is small, there is little decrease in effective saturation magnetic flux density and little decrease in output.

A core that satisfies the above conditions (iv) and (v) can be made low in height while securing the necessary volume, and in this case, is highly efficient and generates a small amount of heat.

Therefore, conditions (ii), (iii) (iv), (i
A ferrite core that satisfies v) at the same time has a low mounting height and a small temperature rise, so there is little decrease in effective saturation magnetic flux density and little decrease in output.

Furthermore, a ferrite core that satisfies all conditions (i) to (V) has a low mounting height (and extremely small temperature rise).

The ferrite core of the present invention achieves these effects without having to have a special shape, and the mold used for manufacturing can be easily produced.

Note that a ferrite core that satisfies the above condition (vi), that is, a ferrite core whose middle leg has a cross-sectional area of 50 mm'' or more, is usually classified as a high-power core.

Conventionally, in the EE type rougherite core known as such a high power core, the above conditions (i) to (v
The dimensional ratio of each part shown in i) is, for example, as follows.

(Conventional Example 1) (i) c/b: 1.00 (ii) d/c=0.47 e/c=0.47 (iii) a/g=6.45 b+2 g (v) =0. 54b+2g (vi) cXb=1 14. 5mm'' Also, examples of the flat EE type core of the present invention include the following.

(Conventional example 2) (i) c/b=2.03 (if) d/c=o, 40 e/c=0.64 (iii) a/g = 7.97 b+2g (V) =0.38b+2g (vi) c X b = 9 8, 8 mm
2. That is, there is no conventionally known high power EE type core that satisfies all the conditions of the present invention.

Incidentally, FIG. 3 of the above-mentioned Japanese Utility Model Publication No. 61-20729 shows a flat core, and when the dimensions of each part of this core are actually measured, the above-mentioned conditions (i) and (ii) are satisfied.

However, as shown in the detailed description, the invention described in the above publication is applied to a small core with a length and width of about 8 to 10 mm, whereas the invention is applicable to a small core with a length and width of about 8 to 10 mm. It exhibits remarkable effects when applied to high-power cores.

Furthermore, the core disclosed in the above publication satisfies the above condition (iii).
Since the mounting height is low (as in the present invention),
And the core width cannot be made small.

Furthermore, the above conditions (ivl, (iv)) are not disclosed at all.

In other words, these conventional cores are not dimensionally designed with the aim of reducing the mounting height and obtaining high efficiency like the ferrite core of the present invention, so even if some of the conditions of the present invention are satisfied, There is no method that satisfies all the conditions and cannot achieve the purpose of the present invention.

It should be noted that the present invention is effective when applied to a sintered core, for example, a multilayer M using a silicon steel plate.
In the type core, even if the dimensions of each part satisfy the above conditions, the loss at high frequencies becomes large, making it unsuitable for use as a high power core.

<Specific Configuration> Hereinafter, a specific configuration of the present invention will be described in detail based on the drawings.

FIG. 1 shows an E-type core half 10. As shown in FIG.

The core half-rest 10 shown in FIG. 1 has a middle leg 11 and a pair of outer legs 12 extending in the length direction, and is connected to the middle leg 11 and a pair of outer legs 2 and extends in the core width direction. It has a back meat part 13 that exists.

The ferrite core of the present invention is usually an EE-type core formed by abutting the legs of such E-type core halves, or an EI-type core formed by abutting E-type core halves and ■-type core halves. Although it is a type core, since the present invention is characterized by its dimensions when assembled into a core, it is not necessarily limited to an EE type or EI type core as long as it has a shape that allows application of each condition in the present invention.

The core of the present invention has a width a, a height b, a middle leg width c, an outer leg width d, a back meat width e, and a distance between the middle leg and outer leg g.
, when the length of the middle leg is β, the following (i), (ii
) and (iii) are simultaneously satisfied, or the following conditions (ii), (iii), (iv) and (v) are simultaneously satisfied, preferably the following conditions (i) to (
All of V) are satisfied.

(i) 2.3≦c/b≦6.0 (ii) 0.4≦d / c≦0.7 0.4≦e / c≦0.7 (iii) 8.0≦a/g≦ 30 Furthermore, the present invention exhibits particularly high effects when applied to a high-power ferrite core, particularly a high-power ferrite core that satisfies the following condition (vi).

(vi) c x b≧50+nm” above condition (i
c/b shown in ) represents the flatness of the middle leg, and the larger this value is, the thicker the flatness of the middle leg becomes.

The ferrite core of the present invention has c/b as described above and has a flattened middle leg compared to a conventional horizontal type core, so it can be made thinner while ensuring the cross-sectional area of the middle leg. be able to.

Since the middle leg has a high degree of flatness, the ratio of the surface area of the middle leg to the cross-sectional area of the middle leg is high, improving heat dissipation and suppressing a rise in the temperature of the core. Therefore, it is suitable for a high power core that satisfies the above condition (vi).

Due to the temperature rise suppressing effect achieved by the present invention, for example, compared to the conventional high power core described above, the temperature rise is smaller even if the minimum cross-sectional area and effective volume are the same, so the effective saturation magnetic flux density is correspondingly higher. (As a result, the output value when forming a transformer improves.

If c/b is less than the above range, such effects will be insufficient. In addition, since the core with c/b exceeding the above range has too high flatness, warping is likely to occur during firing.

By satisfying the above condition (if), the magnetic flux density within the core becomes uniform, and partial magnetic saturation can be prevented. Furthermore, if the above condition (it) is satisfied, the cross-sectional area of the middle leg will be approximately twice that of the outer leg, resulting in the most efficient shape. Furthermore, since the outer legs are also flatter than the conventional core, the above-mentioned effect of suppressing temperature rise is further improved.

Therefore, flat cores that satisfy the above conditions (i) and (ii) have the same material, minimum cross-sectional area, and effective volume, and c
/b is less than the above range, the temperature rise is smaller and the effective saturation magnetic flux density decreases smaller.

Further, such an effect is remarkable in a high frequency range where the core generates a large amount of heat, for example, in a frequency range of 50 kHz or higher, particularly 100 kHz or higher.

There is no particular upper limit to the cross-sectional area cXb of the middle leg, but since it is a flat core, the width when mounted is relatively large, so it is usually about 300 mm''.

The a/g shown in the above condition (Hi) represents the ratio of the distance g between the middle leg and the outer leg to the core width a.

Since the winding applied when mounting the core passes between the middle leg and the outer leg, the distance g between the middle leg and the outer leg is determined depending on the thickness of the winding portion.

When the core height is constant, the height at the time of mounting becomes lower as the thickness of the winding portion becomes thinner, so it is preferable to make the thickness of the winding portion as thin as possible. In this case, the required value of g also becomes smaller. Further, when the core width a is constant, the smaller g is, the thicker the core cross-sectional area can be. When the core cross-sectional area is constant, the smaller g is, the smaller the core width a can be. That is,
The larger a/g is set, the larger the cross-sectional area and the smaller the core.

There is no particular limit to the upper limit of a/g, but it is usually about 30, considering the size of the power supply to which the core of the present invention is applied.

The above condition (iv) is a condition that allows the height to be reduced while ensuring the core volume.

Moreover, the above condition (v) is a condition that limits the range in which the highest efficiency is achieved in a thin core that satisfies the above condition (iv). If the efficiency is high, the heat generated by the core is small. This condition (v) was determined in consideration of the core temperature rise during use.

In the present invention, when the length of the middle leg is β, the following condition (v
It is preferable that ii) is satisfied.

(vii) 4.0≦12/g≦40 This is due to the following reason.

If the value of g is constant and β is large, the winding area can be increased. Therefore, if the number of windings is constant, it becomes possible to wind a thick wire, and copper loss is reduced. Furthermore, since the number of windings can be increased if the wire diameter is the same, it can be used at a lower operating level (magnetic flux density) and iron loss is reduced.

Such an effect is remarkable when 12/g is 4 or more, and is especially remarkable in a high-power core that satisfies the above condition (vi).

There is no particular upper limit of 127g, but it is usually set at 40g considering the size of the product.

There is no particular restriction on the method of manufacturing the ferrite core of the present invention,
It may be manufactured according to a known ferrite manufacturing method that includes molding and firing steps.

Note that since the ferrite core of the present invention does not have a special shape, it can be easily manufactured by horizontal pressing.

The present invention is applied to a horizontally placed ferrite core as described above.

When the ferrite core of the present invention is mounted, usually
It is inserted into a pre-wound bobbin and used as an inductance element in transformers, choke coils, etc.

There is no particular restriction on the bobbin used for the core of the present invention, but since the core of the present invention is thin and may warp during firing, it is preferable to use a bobbin as described below.

Furthermore, since the core of the present invention is a high power core,
It is preferable to use the following bobbin also because it generates a large amount of heat.

FIG. 2 shows a perspective view of a bobbin 1 preferably used for the core of the present invention. In addition, FIG. 2 also shows an E-type core half-hole 10.10 inserted into the cylindrical portion 2 of the bobbin 1.

The bobbin l includes a cylindrical portion 2, a flange 3 formed at both ends of the cylindrical portion 2 in the axial direction, and a piece formed at both axial ends of the cylindrical portion 2 via the flange 3. 4, and a terminal pin 5 implanted in this piece part 4.

The cylindrical part 2 has a cylindrical shape, such as a cylindrical shape or a rectangular cylindrical shape,
The middle leg 11 of the core half-rest 10 is configured to be insertable, and a wire is wound around the outer periphery of the cylindrical portion 2 at the time of mounting.

The collar portion 3 has the function of insulating the winding wound around the outer periphery of the cylindrical portion 2 and the core half-hole 1o.

If necessary, a notch 31 may be provided on the upper surface side of the cylindrical portion 2 of the collar 3 for winding guidance as shown in the drawing.

The piece part 4 includes a chest center part 41 and a pair of piece end parts 4 that are continuous with each other through steps 43 and 43 at both ends of the chest center part 41.
2.42.

The upper surface of the chest center portion 41 is substantially in the same plane as the lower inner surface of the cylindrical portion 2 . Since the step 43 is provided, the upper surface of the piece end portion 42 is lower than the upper surface of the chest center portion 41 (
It has become.

FIG. 3 shows a middle leg 11 and an outer leg 12 on the cylindrical part 2 of the bobbin 1.
FIG. 3 is a front view showing a state in which a middle leg 11 of a half-core core 10 having a curvature in a direction connecting the two is inserted.

The top surface of the piece end 42 of the bobbin 1 is lower than the top surface of the chest center portion 41 (
Therefore, as shown in FIG. 3, the core half 10
The warp can be released, and the middle leg 11 of the warped core half-break 10 can be inserted into the cylindrical part 2.

Further, as shown in FIG. 4, when inserting the middle leg 11 of the core half 10, which is not warped, into the cylindrical part 2,
The back flesh part 13 of the core half body 10 is
can be stably supported.

Note that the step 43 may be perpendicular to the upper surface of the chest center portion 41 as in the illustrated example, or may be an inclined surface or a curved surface with respect to the upper surface of the chest center portion 41.

In addition, the bobbin 1 is not limited to the bobbin 1 having the step 43 in the bridge portion 4 as shown in the illustrated example.
If the core half body 10 is convex on the side on which it is placed, the effect of releasing the warpage of the core as described above can be achieved.

Therefore, in addition to the embodiment in which the step 43 is provided to make the cross section convex as in the illustrated example, the upper surface of the piece end 42 may be a sloped surface that continues to the flat chest center portion 41 without providing the step 43. .

In this case, the inclined surface may be a flat surface, or may be a curved or bent surface. When the surface is curved or curved, it is preferably convex downward.

In any of these cases, the effect of relieving core warpage and facilitating core insertion is achieved.

An L-shaped terminal pin 5 having a circular cross section is planted in the bridge portion 4 .

Both ends of the terminal pin 5 protrude from the side surface of the bridge section 4 opposite to the collar section 3 and from the bottom surface of the bridge section 4, respectively.

Although the number of terminal bins 5 provided is six for each piece in the illustrated example, it may be determined as appropriate depending on the application.

As shown in FIG. 6, embedded lug parts 511 and 512 are embedded in the piece part 4 of the terminal pin 5, and exposed lug parts 52 are provided in the part protruding from the side surface of the piece part 4. is preferably formed.

The embedded tabs 511 and 512 and the exposed tabs 52 are formed by crushing a portion of the terminal bin, and have portions that protrude from the outer circumferential side of the terminal bin 5 in the front and back directions in the paper.

The embedded tabs 511 and 512 have the function of preventing the terminal pin 5 from being pulled out from the piece 4. A plurality of embedded tabs 511 and 512 may be provided, and may be crushed obliquely with respect to the axis of the terminal pin 5.

The exposed tab portion 52 may be located anywhere as long as it protrudes from the bridge portion 4 (or, the exposed tab portion 52 may be the entire portion of the terminal pin 5 that protrudes from the bridge portion 4).

The terminal bottle 5 can be manufactured at low cost by using a so-called round bottle with a circular cross section. However, in order to stabilize the wound wire so that it does not unravel after automatically cutting the winding end, it is necessary to use, for example, a square bin with a rectangular cross section.
By providing the exposed tab portion 52 in a part of the round bottle as shown in the illustrated example, it is possible to realize a terminal bottle that is inexpensive and allows the wound wire to be wound well after the end of the winding is cut.

Note that a square bottle with a rectangular cross section may also be used.

Various dimensions of these embedded projections 511, 512 and exposed projections 52 may be appropriately determined as necessary.

The winding wound around the outer periphery of the cylindrical part 2 is connected to the terminal pin 5.

When the winding passes through the lower surface of the cylindrical portion 2 and is connected to the terminal pin 5, it is preferable to provide a protrusion or groove for guiding the winding on the lower surface of the piece 4.

Further, as shown in the figure, it is also preferable to provide a tapered part 32 at the boundary between the collar part 3 and the bridge part 4 to improve strength.
When providing the tapered portion 32, as shown in the example shown, the core half l
A tapered portion is also provided at the corresponding location of O.

The ratio between the width of the chest center part 41 and the width of the piece end part 42, and the step 4
The dimensions of each part of the bobbin 1, such as the height of 3, may be appropriately determined depending on the material, shape, dimensions, etc. of the core to be combined, but it is preferable, for example, to have the following dimensional ratio.

When the width of the piece end portion 42 is A and the width of the chest center portion 41 is B, it is preferable that 2.0≦B/A≦12.0. Note that the width in this case means the length measured in the direction perpendicular to the two axes of the cylindrical portion, as shown in FIG. If B/A is less than the above range, core half-time off 1
0 becomes difficult to stably support on the upper surface of the chest center portion 41, and if B/A exceeds the above range, the effect of providing the step 43 will be substantially negated.

Note that when providing one step 43, there is no particular limit to its height, but when the height of the step 43 is C, θ= jan-
'The average inclination angle θ expressed as C/A is 0.3 to 15
．． The height is preferably in the range of 0°.

Moreover, even in an embodiment in which the above-described step 43 is provided or not,
The average inclination angle of the upper surface of the piece end portion 42 is preferably 0.3 to 15.0''.

The reason why the average inclination angle is set to 15.0° or less is because a core with extremely large warpage is unsuitable as a product, so there is no need for the average inclination angle to exceed the above range. Further, the lower limit of the average inclination angle may be determined according to the warpage rate allowed for the cores to be combined, but if it is less than 0.3@, the warp absorption effect of the core will almost disappear.

There is no particular restriction on the absolute values of A, B and C, but they are usually within the following ranges.

1.0mm≦A≦30.0+n+.

5.0mm≦B≦50.0mm 0.05mm≦C≦1.0mm Further, the cross-sectional area of the hollow part of the cylindrical portion 2 may be determined according to the cross-sectional area of the middle leg of the core half-opening lO, for example, 5.0 mm≦B≦50.0 mm. 0-500
It is about mm''.

The width of the core half 10 used in combination with such a bobbin 1 (the length of the back part 13) is usually the width of the piece part 4 (measured in the direction perpendicular to the axis of the cylindrical part 2). length) of 8
It is about 0 to 120%.

In addition, the height of the core half-rest 10 is 6 of the height inside the cylindrical part 2
It is about 0 to 100%.

When mounting a core using the bobbin 1, the cylindrical part 2 is usually wound with a wire, and after this winding is connected to the terminal pin 5, a pair of half-core cores 10 and 10 are placed inside the cylindrical part 2. Insert the middle legs 11° and 11 of each core, butt the half cores against each other, and join them. Next, the mounting board is mounted by fitting the terminal pin 5 protruding from the lower surface of the piece 4 into the hole.

There is no particular restriction on the material of the bobbin 1 (it may be made of an insulator such as various resins, but when the core of the present invention is applied to a high-power core, it may be made of various heat-resistant resins such as phenolic resin). It is preferable to use

Further, there is no particular restriction on the method of forming the bobbin 1, but it can be manufactured at low cost by integrally molding each part by injection molding or the like. Note that the terminal pin 5 is usually formed by inserting an L-shaped pin after forming the bobbin.

<Examples> Hereinafter, the present invention will be explained in more detail by giving specific examples.

[Example 1] Core sample No. 1 was produced by firing an E-shaped core half-hole of Mn-Zn ferrite, and joining the middle and outer legs of a pair of core half-holes.

Note that the firing was performed without stacking the molded bodies.

Core samples with different dimensions were prepared in the same manner as this sample.

The dimensions of these samples were as follows.

(Sample No. 1 of the present invention) (i) c/b=3.3 (ii) d/c=0.50 e/c=0.49 (iii) a/g=9, 7b+2g (V) −= 0, 37 b + 2g (vi) c x b = 1 2 1 mm” (
vii) n/g=6. 1 The effective volume of sample No. 1 was 12.7 cm'.

(Comparison sample No. 2) (i) c/b=1 (if) d/c =0.50 e/c=0.49 (iii) a/ g= 2.88 b+2 g (v) −= 0 , 1s b + 2g (vi) c x b = 12 1 mm” (v
ii) I2/g=0.84 The effective volume of sample No. 2 is 13.2CII+
"Met.

(Sample No. 3 of the present invention) (i) c/b = 4.1 (if) d/c = 0.50 e/c = 0.49 (iii) a/ g = 10.6 b + 2g (V) = 0.34b+2g fvi) cXb=1 54mm” (vii)
β/g=6.3 The effective volume of sample No. 3 was 19.2 cm''.

(Comparison sample No. 4) (i) c/b=1.0 (ii) d/c=0.50 e/c=0.49 (iii) a/g=2,9 j2+2e (vi) cXb= 1 54mm” (vii)
ρ/g=1. 0 Sample No. 4 had an effective volume of 20.2 cm''.

Comparative sample No. was measured when the mounting height was measured after 20 turns of winding was wound around each sample.

2, 4.9 mm for inventive sample No. 1
Comparative sample No. 4 is high, and inventive sample No. 4 is high.
, 6.3 mm higher than 3.

Next, each sample was driven by a forward converter method at a frequency of 100 kHz, and the surface temperature was measured.

As a result, comparative sample No. 2 was 2° C. higher than inventive sample No. 1, and comparative sample No. 4 was 3° C. higher than inventive sample No. 3.

In addition, when the effective saturation magnetic flux density of each sample was measured, comparison samples No. 2 and 4, which had a significant temperature rise, showed a decrease in effective saturation magnetic flux density compared to inventive samples No. 1 and 3, respectively. output is 1
It decreased by more than ~2W.

From the results of the above examples, the effects of the present invention are clear.

<Effects of the Invention> According to the present invention, the height when mounted as a transformer or choke coil can be significantly lowered compared to conventional cores.

Furthermore, since the core has high heat dissipation and generates little heat during use, the temperature rise in the core is small. Therefore, there is little decrease in effective saturation magnetic flux density, and high output can be obtained.

Furthermore, the ferrite core of the present invention does not need to have a special shape to achieve this effect.
Easy to manufacture.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a half core constituting the ferrite core of the present invention. FIG. 2 is a perspective view showing the bobbin and the core half-closed. FIG. 3 is a front view showing a state in which the middle leg with a curved core is inserted into the cylindrical part of the bobbin. FIG. 4 is a front view showing a state in which a middle leg with a non-warped core half-opened is inserted into the cylindrical part of the bobbin. FIG. 5 is a front view showing the dimensions of each part of the bobbin. FIG. 6 is a partial cross-sectional view showing a state in which a terminal pin is implanted in a bridge portion of a bobbin. Explanation of symbols l...Bobbin 2...Cylindrical part 3...Flame part 31...Notch part 32...Tapered part 4...Biece part 41...Central chest part 42... - Piece end 43...Step 5...Terminal pin 511.512...Embedded tab section 52...Exposed tab section 10...Core half-rest 11...Middle leg 12...Outer leg 13...Back meat part FIG, 1 Applicant: TDC Co., Ltd. Representative Patent attorney: Yo Ishii - Patent attorney Masu 1) Tatsuya FIG, 3 FrG, 4 FIG, 5 FIG, 6

Claims (1)

[Scope of Claims] (1) A pair of back meat having a middle leg and a pair of outer legs extending in the length direction of the core, and connected to the middle leg and the pair of outer legs and extending in the width direction of the core. A ferrite core that is mounted and used so that the middle leg and the outer leg are substantially parallel to the mounting board, the core width being a, the core height being b, and the middle leg width being When c is the width of the outer leg, d is the width of the back flesh, and g is the distance between the middle leg and the outer leg, the following conditions (i), (ii), and (iii) are simultaneously satisfied. A ferrite core characterized by: (i) 2.3≦c/b≦6.0 (ii) 0.4≦d/c≦0.7 0.4≦e/c≦0.7 (iii) 8.0≦a/g≦ 30 (2) It has a middle leg and a pair of outer legs that extend in the length direction of the core, and has a pair of back flesh parts that are connected to the middle leg and the pair of outer legs and extend in the width direction of the core, A ferrite core is used that is mounted so that the middle leg and the outer leg are substantially parallel to the mounting board, and the width of the core is a, the height of the core is b, the width of the middle leg is c, and the outer leg is When the width of is d, the width of the back flesh is e, the distance between the middle and outer legs is g, and the length of the middle leg is e, the following (ii), (iii),
A ferrite core characterized by simultaneously satisfying the conditions shown in (iv) and (v). (ii) 0.4≦d/c≦0.7 0.4≦e/c≦0.7 (iii) 8.0≦a/g≦30 (iv) 2.5≦l+2e/b+2g≦5. 5(v)0
．． 2≦b/b+2g≦0.8 (3) The ferrite core according to claim 2, satisfying the following condition (i). (i) 2.3≦c/b≦6.0 (4) The ferrite core according to any one of claims 1 to 3, which satisfies the following condition (vi). (vi) cxb≧50mm^2 (5) The ferrite core according to any one of claims 1 to 4, which satisfies the following condition (vii). (vii) 4.0≦l/g≦40