CN201294133Y - Inductor - Google Patents

Abstract

The utility model provides an inductor, which comprises a first magnetic core and a second magnetic core, wherein the first magnetic core is connected with the second magnetic core to form a cavity. A first magnetic post is arranged on the first magnetic core in the cavity, and a second magnetic post, which is coaxial with the first magnetic post, is reversely arranged on the second magnetic core, a gap is left between the end faces of the first magnetic post and the second magnetic post, and a coil is wound on the first magnetic post, the gap and the second magnetic post. A certain gap is arranged between the first magnetic post and the second magnetic post, and the coil is wound on the two magnetic posts, and the magnetic line can concentrate on the periphery of the coil after being electrified. The magnetic inductance lines generated by the current-carrying coil can disperse in the whole space as the part of the current-carrying coil in the gap is not provided with the magnetic post. Compared with a coil which is wound on the whole magnetic post in the prior art, the technical scheme of the inductor increases the saturability resistance of the inductor, and reduces the magnetic conductance rate.

Description

A kind of inductor

Technical field

The utility model belongs to a kind of electronic component, relates in particular to a kind of inductor.

Background technology

A kind of inductor in the market, as shown in Figure 1, it comprises first magnetic core 11 and second magnetic core 12, first magnetic core 11 and second magnetic core, 12 circumferential seals are connected to form cavity 13, first magnetic core 11 is provided with the magnetic post 111 that is wound with coil 14 in cavity 13, has certain clearance between the end face of magnetic post 111 and second magnetic core 12.

Because coil is wound on the magnetic post 111, the line of magnetic induction makes magnetic flux bigger almost along magnetic core, the effective permeability height, and anti-saturability is low.

The utility model content

The technical problems to be solved in the utility model is, a kind of inductor is provided, and can reduce its permeability, improves anti-saturability.

In order to solve the problems of the technologies described above, the utility model provides a kind of inductor, comprises first magnetic core and second magnetic core, and described first magnetic core is connected with second magnetic core and forms cavity.In described cavity, described first magnetic core is provided with the first magnetic post, relatively be provided with the second magnetic post coaxial on described second magnetic core with the described first magnetic post, have certain interval between the end face of described first, second magnetic post, a coil is wound on the described first magnetic post, gap and the second magnetic post.

First, second magnetic intercolumniation has certain clearance, and coil is wound on the two magnetic posts, and after the energising, the magnetic line of force concentrates on around the coil.This current-carrying coil at gap portion owing to there is not a magnetic post, the line of magnetic induction of its generation is that disperse is in whole space, be wound in whole magnetic post with coil in the prior art and compare, technical solutions of the utility model have improved the anti-saturability of inductor, have reduced permeability.

Description of drawings

Fig. 1 is the structural representation of a kind of inductor of providing of prior art;

Fig. 2 is the decomposing schematic representation of a kind of inductor of providing of the utility model embodiment;

Fig. 3 is that the structure and the position of first, second magnetic core among Fig. 2 concerns schematic diagram;

Fig. 4 is the elevational schematic view of the utility model embodiment;

Fig. 5 is the structural scheme of mechanism of first or second magnetic core among Fig. 3;

Fig. 6 the utility model embodiment gap thickness and inductance direct current concern schematic diagram;

Fig. 7 is the magnetic hysteresis loop schematic diagram of magnetic core under the gapped and two kinds of situations in no gap of the utility model embodiment.

Embodiment

In order to make the purpose of this utility model, technical scheme and advantage clearer,, the utility model is further elaborated below in conjunction with drawings and Examples.Should be appreciated that specific embodiment described herein only in order to explanation the utility model, and be not used in qualification the utility model.

See also Fig. 1 and Fig. 2, the utility model embodiment provides a kind of inductor, comprises that first magnetic core 2 and second magnetic core, 3, the first magnetic cores 2 are connected with second magnetic core 3 and form cavity 4.In cavity 4, first magnetic core 2 is provided with and relatively is provided with the second magnetic post 31 coaxial with the first magnetic post 21 on the first magnetic post, 21, the second magnetic cores 2.Having certain interval 41, one coils 5 between the end face of first, second magnetic post 21,31 is wound on the first magnetic post 21, gap 41 and the second magnetic post 31.

As shown in Figure 3 and Figure 4, in the present embodiment, inductor is the Surface Mount power inductor, and its profile is rectangular.The bottom of inductor is provided with base 6, is provided with three pads 61 in the bottom surface of base 6.With three pads 61 accordingly, base 6 is provided with first projection 62 and second projection 63, first, second projection 62,63 is arranged at the both sides of base 6 end faces respectively, and has formed the accommodation space 64 that can hold second magnetic core 2.The position that is provided with two groove 65, two grooves 65 in first projection 62 is corresponding with the position in two pads 61, and second projection 63 is corresponding with another pad 61.

As shown in Figure 5, first, second magnetic core 2,3 is also rectangular, and first, second magnetic core 2,3 circumferentially all has flange 42, in order to draw the end line of coil 5, flange 42 both-side openings.First, second magnetic post 21,31 adopts the MnZn Ferrite Material to make, and its diameter of section is identical, and is arranged at the inboard central authorities of first, second magnetic core 2,3 respectively, makes two magnetic cores be " E " type.

Because the volume of Surface Mount inductor is less, the length of first, second magnetic post 21,31 is short, therefore coil 5 is turned to flatwise coil, and coil adopts enamel covered wire.Be cylindricality after this flatwise coil coiling, the diameter of its diameter and magnetic post 21 is complementary.Coil has two end lines 51, and after first, second magnetic core 2,3 was installed in the accommodation space 64 of base 6, two end lines 51 laid respectively in two grooves 65, and electrically connect with two pads 61.

What of point mucilage binding carrying capacity not only can influence the reliability of adhesive strength, also can directly influence magnetic core gap 41 sizes, cause electrical property along with the glue amount what and change.For the effective size of control gap 41, can make it easy on plate glass, carry out frictioning by adjusting the viscosity of glue, remove viscose glue with magnetic core again and make up.Thereby it is suitable to reach the glue amount, is evenly distributed, and reaches firm purpose of connecting.In the present embodiment, it is bonding to adopt epoxide-resin glue to carry out between first, second magnetic core 2,3 and between second magnetic core 3 and the base 6, and flatwise coil adopts welding to be connected with bottom land 61 with base 6, with the composition loop and guarantee its reliability.

Therefore, 21,31 on first, second magnetic post has certain clearance 41, and coil 5 is wound on the two magnetic posts, and after the energising, the magnetic line of force concentrates on around the coil 5.This current-carrying coil 5 in the gap 41 parts owing to there is not a magnetic post, the line of magnetic induction of its generation is that disperse is in whole space, be wound in whole magnetic post with coil in the prior art and compare, technical solutions of the utility model have improved the anti-saturability of inductor, have reduced permeability.

The Surface Mount inductor that present embodiment provides, the length in single product specification gap 41 is controlled at 0.1～0.2mm, and its inductance value allowed band 10 (± 20%) μ H requires specified dc bias current 5.0A, D.C. resistance DCR≤13.5m Ω, Q value (quality factor) is greater than 30.The overall dimension of product is little, in limited volume, reaches higher rated current and extremely low D.C. resistance.When gap 41 is set to 0.125mm, can makes the effective permeability decline of inductor minimum, and improve the anti-saturability of inductor greatly.

For first, second magnetic core 2,3 of E type, under certain frequency and coil turn, measure, the inductance direct current superimposed characteristics of magnetic core under 41 thickness of different gaps as shown in Figure 6, wherein curve 1,2,3 is respectively 0.1mm, 0.2mm and 0.3mm corresponding to gap thickness.Increase empty gap thickness, can obtain higher inductance value under higher bias direct current, and the curve descending grade is tending towards reducing, but under lower bias current, its inductance value is lower, promptly effective permeability is lower.

As shown in Figure 7, A1 is gapless magnetic hysteresis loop, and A2 is gapped magnetic hysteresis loop.For being operated under the big electric current (magnetic flux density), first, second magnetic core 2,3 is unlikely saturated, in magnetic circuit, increase gap 41, the dc superposition characteristic of inductor improves, mainly be because gap 41 adds ambassador's saturation hysteresis loop and tilts to X direction, first, second magnetic core 2,3 saturation magnetizations need bigger external magnetic field.Therefore introduce gap 41 in first, second magnetic post 21,31 and both can prevent saturation magnetization, also reduced Br (residual magnetic flux density) in addition, Δ B is increased greatly.

After first, second magnetic post 21,31 is increased gap 41, the BH curve slope is reduced, the magnetic core saturation point be moved to right, thereby increased the ability of the anti-dc magnetization of magnetic core.But the adding in gap 41 makes permeability descend again, so there is individual optimum value in gap 41, promptly when inductance coil passed through peak inrush current, magnetic core did not enter saturated, does not cause the too low of permeability decline simultaneously again.So adopt first, second magnetic core 2,3 of E type, can utilize the gap 41 of 21,31 on first, second magnetic post of center to control easily.According to cylindrical edge permeability formula (empirical equation):

$v=r\ln [1+\frac{2x+2\sqrt{x^2+x{L}_g}}{L_g}]$

In the formula:

V--inductor current amount, H;

The r--cylindrical radius, m;

The effective permeability of χ--cylinder;

The length in gap between the Lg--cylinder, m.

Again according to the maximum current of the desired inductance value of inductor, overall dimension, requirement, determine μ i (permeability), the Bs (saturation flux density) of core material thus obtain χ, r, V, obtain Lg ≈ 0.2mm by estimation.

Then, utilize the direct current biasing power supply to be connected with accurate electric inductance measuring-testing instrument is supporting, when making feeding inductor direct current reach 5A, when the inductance value decline of inductor is no more than zero current 20% (Δ L≤20%L), think that promptly magnetic core has reached the highest Bm (magnetic flux density peak value), the gap 41 of this moment is best clearance length.If when feeding Imax (maximum current), inductance value descends and surpasses 20%, illustrates that gap 41 is little, can suitably strengthen; If when feeding Imax, inductance value does not descend (in the number of turns of setting, inductance value does not reach the requirement of agreement), illustrates that gap 41 is big, can suitably reduce, and after repetition test and checking, determines best clearance length.

Through experiment, the overall dimension of present embodiment product and external certain product and electrical property contrast see Table 1, table 2;

Table 1 size contrast table

Table 2 electrical property contrast table

The above only is preferred embodiment of the present utility model; not in order to restriction the utility model; all any modifications of within spirit of the present utility model and principle, being done, be equal to and replace and improvement etc., all should be included within the protection range of the present utility model.

Claims (7)

1, a kind of inductor, comprise first magnetic core and second magnetic core, described first magnetic core is connected with second magnetic core and forms cavity, it is characterized in that: in described cavity, described first magnetic core is provided with the first magnetic post, relatively be provided with the second magnetic post coaxial with the described first magnetic post on described second magnetic core, have certain interval between the end face of described first, second magnetic post, a coil is wound on the described first magnetic post, gap and the second magnetic post.

2, inductor as claimed in claim 1 is characterized in that: described coil is a flatwise coil.

3, inductor as claimed in claim 1 is characterized in that: the bottom of described inductor is provided with base, and described first, second magnetic core is fixed on the described base.

4, inductor as claimed in claim 3 is characterized in that: described inductor is SMD inductor, and the bottom surface of described base has three pads, and described coil and pad electrically connect.

5, as each described inductor of claim 1-4, it is characterized in that: described gap is 0.1～0.2mm.

6, inductor as claimed in claim 5 is characterized in that: the rated direct current of described inductor is 5.0A, inductance value allowed band 10 (± 20%) μ H, and D.C. resistance≤13.5m Ω, the Q value is greater than 30.

7, inductor as claimed in claim 6 is characterized in that: described gap is 0.125mm.

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