JP7193908B2 - Reactor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-vehicle reactor used in a drive system of a hybrid vehicle or an electric vehicle.

Conventionally, reactors have been used for a wide variety of purposes. Typical reactors include series reactors that are connected in series to the motor circuit to limit the current during a short circuit, parallel reactors that stabilize the current sharing between parallel circuits, and machines that limit the current during a short circuit and are connected to them. Current-limiting reactors for protection are known.

Since these reactors are commercialized so as to have optimum specifications for each application, reactors with various shapes, sizes and structures have been proposed. For example, core types include pot cores having a pot shape, and many of them are designed according to user specifications.

JP-A-2006-310550

It is expected that the reactor will efficiently secure a desired inductance and be miniaturized. In recent years, with the diversification of reactors, each reactor is required to have improved performance. For example, a reactor having a pot core is required to improve heat dissipation. In particular, there is a demand for a reactor that exhibits better heat dissipation in a usage environment in which the amount of heat generated increases due to an increase in current, etc., and the ambient temperature rises.

The present invention has been proposed to solve the above-described problems, and an object of the present invention is to provide a reactor that achieves miniaturization and improved heat dissipation by a configuration in which an opening is formed in the core.

To achieve the above object, the present invention provides a reactor comprising a coil and a core, wherein the core comprises a middle leg around which the coil is wound; and a peripheral wall portion and a yoke portion that are not rotated, and an opening is formed in the peripheral wall portion and the yoke portion in a rectangular shape in plan view, the coil is exposed at the opening, and the opening is , the long side is formed on the yoke portion, the short side is formed on the peripheral wall portion, the width of the opening portion and the width of the middle leg portion are the same, and the yoke relative to the horizontal cross-sectional area Aa of the middle leg portion Db=2Bb/Aa is the ratio of the vertical cross-sectional area 2Bb of the portion, and Dc=2Bc/Aa is the ratio of the horizontal cross-sectional area 2Bc of the peripheral wall to the horizontal cross-sectional area Aa of the middle leg. The value Dave=(Db+Dc)/2 satisfies 0.5≦Dave≦0.9.

The width of the opening may be the same as the width of the middle leg. Also, the opening may be formed so as to expose the end face of the coil in a rectangular shape. The peripheral wall portion may be provided so as to cover the outer periphery of the coil. Furthermore, the yoke portion may be provided so as to connect the middle leg portion and the peripheral wall portion.

According to the reactor according to the present invention, the opening is formed in a rectangular shape in a plan view in the peripheral wall portion and the yoke portion where the coil is not wound, and the coil is exposed at the opening to efficiently secure the inductance. It is possible to achieve miniaturization by reducing the volume while reducing the volume, and heat is not accumulated around the coil, thereby improving the heat radiation performance.

1 is a perspective view of the first embodiment; FIG. 1 is an exploded perspective view of the first embodiment; FIG. FIG. 2 is a perspective view of essential parts of the first embodiment; 5 is a graph showing the relationship between the area ratio (average value) and the volume ratio of each part of the reactor in the first embodiment; 4 is a graph showing the relationship between volume and heat dissipation in the first embodiment and comparative example.

[First embodiment]
[composition]
The configuration of the first embodiment will be specifically described with reference to FIGS. 1 to 3. FIG. FIG. 1 is a perspective view of a reactor to which the first embodiment is applied, FIG. 2 is an exploded perspective view of the same, and FIG. 3 is a perspective view of the essential parts thereof. The first embodiment is applied to a pot core that reduces leakage inductance by housing a coil.

As shown in FIGS. 1 to 3, the reactor 1 is provided with a cylindrical coil 20 and a pot core 10 that accommodates the coil 20. As shown in FIG. The pot core 10 is composed of two upper and lower middle leg portions 11 and a peripheral wall portion 12 , and a yoke portion 13 that serves as the upper and lower surface portions of the reactor 1 .

The middle leg portion 11 is arranged in the center of the pot core 10, and is formed in a columnar shape by abutting two vertically divided portions. The peripheral wall portions 12 are arranged facing each other so as to surround the middle leg portion 11 in the left-right direction, and are formed in a substantially arc shape by abutting two vertically divided portions. Moreover, the peripheral wall portion 12 is formed so as to cover the outer peripheral portion of the coil 20 . A spacer may be provided at the butted portion of the middle leg portion 11 and the peripheral wall portion 12, or an adhesive may be applied.

The yoke portion 13 is composed of two oval-shaped portions facing each other in the vertical direction. The upper yoke portion 13 is provided so as to connect the upper end portion of the middle leg portion 11 and the upper end portion of the peripheral wall portion 12 , and the lower yoke portion 13 connects the lower end portion of the middle leg portion 11 and the lower end portion of the peripheral wall portion 12 . It is provided so as to connect the part. These upper and lower yoke portions 13 are arranged to face the upper and lower end faces of the coil 20 .

A coil 20 is wound around the middle leg portion 11 of the pot core 10 . That is, the middle leg portion 11 is the winding portion of the coil 20, and the middle leg portion 11 is the magnetic flux generating portion. The peripheral wall portion 12 and the yoke portion 13 are non-wound portions where the coil 20 is not wound, and the peripheral wall portion 12 and the yoke portion 13 form two closed magnetic circuits. Thus, in the pot core 10, the magnetic flux generated in the middle leg portion 11 is divided into two directions in the width direction of the reactor 1, and flows in the order of the upper yoke portion 13, the left and right peripheral wall portions 12, and the lower yoke portion 13, respectively. and return to the middle leg portion 11 .

The reactor 1 is formed by housing the coil 20 in the pot core 10, putting it in a case (not shown), and pouring a filling material into it. Resins with high thermal conductivity, such as silicone resins, epoxy resins, and urethane resins, are suitable as fillers, and a mixture of a plurality of types of resins may also be used. Also, from the viewpoint of improving heat dissipation, a filler that has been agitated and defoamed in a vacuum may be used.

The coil 20 is, for example, an enamel-coated copper wire, and may be a conductive wire having an insulating coating, and an edgewise coil of rectangular wire is suitable. Since the coil 20 is wound around the cylindrical middle leg portion 11, its planar shape is circular. When the coil 20 is wound around the middle leg 11 , the center of the coil 20 is aligned with the center of the middle leg 11 .

The pot core 10 may be provided with cooling means for directly cooling the pot core 10 . The pot core 10 is made of a powder magnetic core, a ferrite magnetic core, a silicon steel plate, or the like. Among them, the dust core has a high saturation magnetic flux density, so that the pot core 10 has excellent DC superposition characteristics.

When a silicon steel plate is used for the pot core 10, it is common to provide a gap between the middle legs 11 facing each other in the vertical direction in order to improve DC superimposition characteristics. When a dust core is used as the pot core 10, there are minute gaps dispersed in the core, so there is no need to provide separate gaps.

A rectangular opening 14 is formed in the peripheral wall portion 12 and the yoke portion 13 in plan view. The opening 14 exposes a part of the outer circumference of the coil 20 and the upper and lower end surfaces of the coil 20 . Two openings 14 are formed in the pot core 10 so as to face each other in the left-right direction.

The opening 14 is integrally formed from the peripheral wall portion 12 to the yoke portion 13 and has a quadrangular shape when viewed from the front. A rectangular portion in plan view of the opening 14 is surrounded by a central long side connecting arbitrary two points on the end surface of the coil 20 and left and right short sides extending perpendicularly from both ends of the long side. formed by

In the rectangular opening 14 , long sides are formed on the yoke portion 13 and short sides are formed on the peripheral wall portion 12 . As described above, the upper and lower yoke portions 13 are arranged to face the upper and lower end faces of the coil 20, so that the upper and lower end faces of the coil 20 are exposed by forming the openings 14 in the yoke portion 13. .

Further, as described above, since the two left and right peripheral wall portions 12 are arranged so as to cover the outer peripheral portion of the coil 20, by forming the short side portion of the opening portion 14 in the peripheral wall portion 12, the outer peripheral portion of the coil 20 is reduced. Some will be exposed. The peripheral wall portion 12 on which the short side portions of the opening 14 are formed protrudes outward when viewed from the center of the pot core 10 by the amount of the long side portions of the opening portion 14 formed on the yoke portion 13 . is formed in That is, the shape of the yoke portion 13 is substantially weight-like in plan view with the two openings 14 formed therein.

As shown in FIG. 3, the horizontal cross-sectional area of the middle leg portion 11 is Aa, the vertical cross-sectional area of one of the upper and lower yoke portions 13 is Bb (lower side in FIG. 3), and the horizontal Letting the cross-sectional area be Bc (left side in FIG. 3), the ratio of the vertical cross-sectional area 2Bb of the yoke portion 13 to the horizontal cross-sectional area Aa of the middle leg portion 11 is Db=2Bb/Aa, and the horizontal cross-sectional area Aa of the middle leg portion 11 is The ratio of the horizontal cross-sectional area 2Bc of the peripheral wall portion 12 is set to Dc=2Bc/Aa. In the first embodiment, the average value Dave=(Db+Dc)/2 of the ratio Db and the ratio Dc is obtained, and the range is set to 0.5≦Dave≦0.9. More preferably, the average value Dave may be 0.7.

[Example]
Examples 1 to 7 according to the first embodiment will be described with reference to Table 1 and the graph shown in FIG.
(Table 1)

As shown in Table 1, the data of Examples 1 to 7 are obtained by changing the horizontal cross-sectional area of the middle leg portion 11 and the peripheral wall portion 12 and the vertical cross-sectional area of the yoke portion 13 so that the inductance performance is almost the same. It is an analytical value. Regarding the average value Dave, the average value Dave of Example 1 is 1, and the average values Dave of Examples 2 to 7 are 0.9, 0.8, 0.7, 0.6, 0.5, 0.4. As shown in Table 1 and the graph in FIG. 4, when the volume ratio of Example 1 is 100%, the volume ratios of Examples 2 to 7 are 99%, 99%, 96%, 98%, and 99%, respectively. , 102%.

[Action and effect]
The actions and effects of the first embodiment are as follows.
(a) In the first embodiment, the peripheral wall portion 12 and the yoke portion 13 are provided with the openings 14 through which the coils 20 are exposed. Therefore, even in a use environment in which the ambient temperature rises due to a large current or the like, excellent heat dissipation can be exhibited, and the performance of the reactor 1 is stabilized.

Here, with reference to Table 2 and FIG. 5, the effects of this embodiment will be specifically described. In Table 2, with respect to Comparative Examples 1 to 4 and Example 8 according to the first embodiment, the number of turns and inductance of the coil are constant, and the volume and the temperature of the thermal analysis value in the comparative example and the first embodiment showing relationships. Comparative Examples 1 to 4 are PQ cores having fan-shaped openings in plan view. The aperture angles of Comparative Examples 1 to 4 are 130° for Comparative Example 1, 135° for Comparative Example 2, 140° for Comparative Example 3, and 150° for Comparative Example 4. The temperatures in Table 2 are thermal analysis values when the loss conditions shown in Table 2 are applied to the core and coil.

(Table 2)

The graph in FIG. 5 shows the relationship between volume and heat dissipation in Comparative Examples 1 to 4 and Example 8. In FIG. As is clear from this graph, the thermal analysis value of Example 8 according to the first embodiment deviates greatly from the approximate curve of the thermal change of the PQ core assumed in Comparative Examples 1 to 4. It has become. That is, in the first embodiment, by providing the opening 14 formed in a rectangular shape in plan view, it is possible to obtain a higher heat radiation effect than the PQ core having a fan-shaped opening in plan view.

The shape of the PQ core is determined only from the viewpoint of ensuring inductance, without considering heat dissipation. Therefore, the PQ core uses a yoke portion that radially expands from the middle leg portion toward the peripheral wall portion so that the flow of magnetic flux in the yoke portion becomes favorable and the cross-sectional area of the peripheral wall portion is increased.

On the other hand, if the opening 14 having a rectangular shape in plan view is formed as in the present embodiment, the flow of magnetic flux in the yoke portion 13 becomes non-uniform, which is disadvantageous from the viewpoint of inductance. In other words, in the present embodiment, unlike the PQ core, the focus is not only on securing the inductance, but also on improving heat dissipation while securing the inductance.

(b) Although the first embodiment focuses on improving heat dissipation, the efficiency of ensuring inductance is not lowered. When comparing the volume ratios of Comparative Examples 1 to 4 and Example 8 with the volume ratio in Comparative Example 1 being 100.0%, as shown in Table 2 above, Comparative Example 4 was 107.1%. reach.

On the other hand, the volume ratio of Example 8 according to the first embodiment is 105.3%. That is, when compared with Comparative Example 4, Example 8 is advantageous not only in terms of heat dissipation but also in terms of efficiency in ensuring inductance. As described above, in the first embodiment, it is possible to improve heat dissipation and the efficiency of ensuring inductance in a well-balanced manner, and to stably realize miniaturization of the reactor 1 .

Moreover, the ratio of the vertical cross-sectional area 2Bb of the yoke portion 13 to the horizontal cross-sectional area Aa of the middle leg portion 11 is Db=2Bb/Aa, and the ratio of the horizontal cross-sectional area 2Bc of the peripheral wall portion 12 to the horizontal cross-sectional area Aa of the middle leg portion 11. is assumed to be Dc=2Bc/Aa, and in this embodiment, the average value Dave=(Db+Dc)/2 of Db and Dc is desirably 0.5 to 0.9.

Therefore, in Examples 2 to 6 in Table 1 above, in which the average value Dave is 0.5 to 0.9, the inductance performance is almost the same, but the volume ratio of Example 1 in which the average value Dave = 1 is Assuming 100%, the volume ratio can be suppressed to less than 100%. In the first embodiment as described above, the cross-sectional areas of the peripheral wall portion 12 and the yoke portion 13, which are the non-wound portions, are averaged and the range thereof is set. Optimization of the dimensions of 12 and yoke portion 13 can be easily achieved.

(c) In the first embodiment, since the short sides of the rectangular opening 14 in plan view are formed in the peripheral wall 12, the horizontal cross-sectional area Bc of the peripheral wall 12 is can be efficiently secured. As a result, it becomes difficult for the coil 20, which is the magnetic flux generating source, to generate a region having no magnetic path, and it is possible to easily obtain the inductance.

[Other embodiments]
The present invention is not limited to the above embodiments. It can be embodied in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included within the scope, gist, and equivalents of the invention.

For example, the shape of the opening 14 can be appropriately selected within the range of a rectangular shape in plan view, and the linearly formed portion may be formed with a curved line. Further, the opening 14 does not have to be square when viewed from the front, and may be circular.

For example, the width of the opening 14 may be the same as the width of the middle leg 11 . If the width of the opening 14 is made larger than the width of the middle leg 11, the heat dissipation is improved, but the cross-sectional area of the peripheral wall 12 is reduced and the inductance is reduced. Therefore, in order to secure a desired inductance, the width of the peripheral wall portion 12 must be increased, which causes the reactor 1 to become large. On the other hand, if the width of the opening 14 is narrower than the width of the middle leg 11, the inductance can be easily ensured, but the heat dissipation deteriorates. Therefore, by setting the width of the opening 14 to be the same as the width of the middle leg 11, it is possible to obtain a good balance between excellent heat dissipation and ease of ensuring inductance.

In the above embodiment, the pot core 10 is applied. The shape of the core can be changed as appropriate. Furthermore, in each of the above-described embodiments, two openings are formed facing each other, but it is not necessary to divide the opening into two evenly in the left-right direction. may

In the first embodiment, the vertical cross-sectional area 2Bb of the yoke portion 13 and the horizontal cross-sectional area 2Bc of the peripheral wall portion 12 may be the same value or different values. Further, in the above embodiment, the size of the reactor 1 is reduced by providing an opening. That is, when reducing the volume of the reactor 1, the height dimension of the yoke portion 13 may be reduced, or the dimensions of the reactor 1 in the width direction and the depth direction may be reduced.

DESCRIPTION OF SYMBOLS 1... Reactor 10... Pot core 11... Middle leg part 12... Peripheral wall part 13... Yoke part 14... Opening part

Claims (4)

In a reactor with a coil and core,
The core is
a middle leg around which the coil is wound;
a peripheral wall portion and a yoke portion arranged around the middle leg portion and around which the coil is not wound;
forming an opening in a rectangular shape in plan view in the peripheral wall portion and the yoke portion, and exposing the coil at the opening;
The opening has long sides formed in the yoke portion and short sides formed in the peripheral wall portion,
The width of the opening and the width of the middle leg are the same,
The ratio of the vertical cross-sectional area 2Bb of the yoke portion to the horizontal cross-sectional area Aa of the middle leg portion is Db=2Bb/Aa, and the ratio of the horizontal cross-sectional area 2Bc of the peripheral wall portion to the horizontal cross-sectional area Aa of the middle leg portion is Dc. = 2Bc/Aa,
A reactor characterized in that an average value Dave=(Db+Dc)/2 of Db and Dc satisfies 0.5≦Dave≦0.9. 2. The reactor according to claim 1, wherein the opening is formed so as to expose the end surface of the coil in a rectangular shape. 3. The reactor according to claim 1, wherein the peripheral wall portion is provided so as to cover the outer circumference of the coil. The reactor according to any one of claims 1 to 3 , wherein the yoke portion is provided so as to connect the middle leg portion and the peripheral wall portion.

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