CN112017854A - Inductance device and manufacturing method thereof - Google Patents

Abstract

The embodiments of the present application relate to an inductance device and a method for manufacturing the same. The inductance device of the embodiment of the present application includes an inductance coil and two magnetic cores, the two magnetic cores are stacked on top of each other in a manner of corresponding opening positions, and the inductance coil is wound around the central pillars of the two magnetic cores; A gap is arranged between the central pillars of the two magnetic cores, a structural member is arranged in the gap, and one or more chambers are jointly enclosed between the structural member and the central pillars of the two magnetic cores, Each of the chambers is structured such that the volume of air contained in the chamber is stretched or compressed by the magnetic field force generated by the central column of the magnetic core during operation. The inductance device of the embodiment of the present application can reduce the vibration of the magnetic core of the inductance device and reduce the noise generated inside the inductance device.

Description

Inductive device and method of making the same

technical field

The embodiments of the present application relate to the technical field of inductors, and in particular, to an inductive device and a manufacturing method thereof.

Background technique

With the development of intelligent technology, the use of switching power supply is inseparable from electronic products in all walks of life. As a high-efficiency power supply device, the application of switching power supply has attracted much attention. Transformers, inductors, etc. are indispensable inductive devices in switching power supplies. In the circuit of the switching power supply, the inductance device is connected to the semiconductor device such as the switch tube and diode. During operation, the change of the magnetic circuit brings about the change of the electromagnetic force, which will cause the magnetic core to vibrate and generate a large noise. This noise exists in the Inside the inductive device, it is difficult to eliminate.

The most serious part of the inductance device that produces vibration and noise is generally the central column of the magnetic core. The traditional solution is generally to dispense glue on the central column of the magnetic core. The glue has both the function of buffer force and the function of bonding the two-lobed magnetic core. The traditional scheme uses the adhesive as a damping material to alleviate the influence of the electromagnetic force of the central column of the magnetic core on the magnetic core, but the effect of this method on the electromagnetic force is limited, due to the large instability of the adhesive, especially The buffering effect on the electromagnetic force will also change after curing. For different applications, this method may not always achieve the desired effect.

SUMMARY OF THE INVENTION

The embodiments of the present application provide an inductance device and a manufacturing method thereof, which can reduce the vibration of the magnetic core of the inductance device and reduce the noise generated inside the inductance device.

In a first aspect, an embodiment of the present application provides an inductance device, including:

an inductance coil and two magnetic cores, the two magnetic cores are stacked on top of each other in a manner corresponding to the opening positions, and the inductive coil is wound on the central pillars of the two magnetic cores;

A gap is arranged between the central pillars of the two magnetic cores, a structural member is arranged in the gap, and one or more chambers are jointly enclosed between the structural member and the central pillars of the two magnetic cores, Each of the chambers is structured such that the volume of air contained in the chamber is stretched or compressed by the magnetic field force generated by the central column of the magnetic core during operation.

Optionally, the structural member includes one or more sub-structural members, and the one or more sub-structural members and the central pillars of the two magnetic cores together form one or more of the cavities.

Optionally, the chamber includes an airtight chamber, and the inner space of the airtight chamber is airtight relative to the outside.

Optionally, the chamber includes a non-sealed chamber, and the non-sealed chamber is provided with an air inlet channel connected to the outside.

Optionally, the air intake channel is a void inside the material of the substructure.

Optionally, the air intake passage is a gap formed by the sub-structure.

Optionally, the width of the intake passage is smaller than the width of the structural member enclosing the chamber to which the intake passage belongs.

Optionally, the ratio between the width d of the intake passage and the width D of the structural member enclosing the chamber to which the intake passage belongs is greater than 1/10 and less than 1/5.

Optionally, the shape of the sub-structure is annular, and when there are multiple sub-structures, a plurality of the sub-structures are nested and arranged in the gap.

Optionally, the structural member is made of elastic material.

Optionally, the structural member is made of a viscoelastic material, or the structural member is fixed to the gap through an adhesive material.

Optionally, the structural member is epoxy resin glue.

In a second aspect, an embodiment of the present application provides a method for manufacturing an inductance device, including the following steps:

Stack the two magnetic cores on top of each other in a manner corresponding to the opening positions;

A structural member is arranged in the gap between the central columns of the two magnetic cores, and the structural member and the central columns of the two magnetic cores together form one or more cavities, each of the cavities The structure of the chamber is such that the volume of air contained in the chamber is stretched or compressed by the magnetic field force generated by the central column of the magnetic core during operation;

The inductance coils are wound around the central pillars of the two magnetic cores.

In the embodiment of the present application, a structural member is arranged in the gap between the central columns of the two magnetic cores stacked on top of each other, so that one or more cavities are enclosed between the structural member and the central column of the upper and lower magnetic cores The structure of the chamber is such that the volume of the air contained in the chamber is stretched or compressed by the magnetic field force generated by the central column of the magnetic core during operation. "Being compressed to form a reaction force, when the air contained in the chamber is stretched, this part of the air also forms a reaction force in order to "resist" being stretched, and the reaction force generated by the air contained in the above-mentioned chamber can offset the magnetic core. The electromagnetic force generated by the central column of the magnetic core can buffer the electromagnetic force, thereby reducing the vibration of the magnetic core and reducing the noise generated inside the inductance device.

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

Description of drawings

FIG. 1 is a schematic diagram of dispensing glue in a magnetic core in an example of the prior art;

FIG. 2 is a schematic structural diagram of an inductive device provided in an exemplary embodiment;

3 is a schematic diagram of a structure of an inductive device provided in an exemplary embodiment;

FIG. 4 is a schematic diagram of a core column and a structural member when the magnetic cores are stacked on top of each other provided in an exemplary embodiment;

FIG. 5 is a schematic diagram of the action principle of the airtight air provided in an exemplary embodiment as a buffer force;

FIG. 6 is a schematic diagram of the action principle of the airtight air provided in an exemplary embodiment as a buffer force;

FIG. 7 is a schematic diagram of a structure of an inductive device provided in an exemplary embodiment;

FIG. 8 is a schematic diagram of a structure of an inductive device provided in an exemplary embodiment;

FIG. 9 is a flowchart of a method of fabricating an inductive device provided in an exemplary embodiment.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present application clearer, the embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the embodiments of the present application, all other embodiments obtained by persons of ordinary skill in the art without creative work fall within the protection scope of the embodiments of the present application.

Terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. As used in the embodiments of this application and the appended claims, the singular forms "a," "the," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It will also be understood that the term "and/or" as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

Where the following description refers to the drawings, the same numerals in different drawings refer to the same or similar elements unless otherwise indicated. The implementations described in the illustrative examples below are not intended to represent all implementations consistent with this application. Rather, they are merely examples of apparatus and methods consistent with some aspects of the present application, as recited in the appended claims. In the description of this application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and are not necessarily used to describe a specific sequence or sequence, nor can understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

Also, in the description of the present application, unless otherwise specified, "a plurality" means two or more. "And/or", which describes the association relationship of the associated objects, means that there can be three kinds of relationships, for example, A and/or B, which can mean that A exists alone, A and B exist at the same time, and B exists alone. The character "/" generally indicates that the associated objects are an "or" relationship.

The traditional inductance device is usually composed of two magnetic cores, each magnetic core includes a central column and two side columns, the two magnetic cores are stacked on top of each other in a manner corresponding to the opening positions, and the inductance coil is wound on two of the The center column of the magnetic core forms an inductive device.

In this embodiment of the present application, the inductive device may specifically be an inductor, or one of the inductors in a transformer.

Figure 1 is a schematic diagram of the structure of one of the magnetic cores. As shown in Figure 1, the height of the central column of the magnetic core is less than the height of the two offset columns on both sides of the central column, so that the two magnetic cores are placed between the stacked central columns. There is a very narrow air gap. The function of the air gap is to reduce the magnetic permeability. The air gap can avoid the magnetic saturation phenomenon under the large AC signal or DC bias and better control the inductance.

The most serious part of the inductance device that produces vibration and noise is generally the central column of the magnetic core. As shown in Figure 1, the traditional solution is generally to dispense glue on the central column of the magnetic core. The function of the lobed magnetic core can reduce the work done by the electromagnetic force on the magnetic core, thereby achieving the effect of reducing noise. However, the hardness of the glue after hardening is relatively large, and the buffering effect on the high-frequency vibration force is relatively limited.

In response to this technical problem, an embodiment of the present application provides an inductance device, as shown in FIG. 2 , in an exemplary embodiment, the inductance device includes an inductance coil (not shown), a magnetic core 1 and a magnetic Core 2, the magnetic core 1 includes a central column 11, the magnetic core 2 includes a central column 21, and the magnetic core 1 and the magnetic core 2 are stacked on top of each other in a manner corresponding to the opening positions. Among them, the magnetic core 1 and the magnetic core 2 can be any magnetic core with a central column, such as E-type magnetic core, EE-type magnetic core, EQ-type magnetic core, PQ-type magnetic core, EFD-type magnetic core and ECR-type magnetic core Magnetic cores, etc., in the embodiment of the present invention, the magnetic core 1 and the magnetic core 2 are EQ-type magnetic cores as an example for illustration.

In FIG. 2 , the magnetic core 1 further includes two offset columns 12 located on both sides of the central column 11 , and the magnetic core 2 also includes two offset columns 22 located on both sides of the central column 21 . Each of the side posts 12 abuts against the two side posts 22 of the magnetic core 2 .

A gap 3 is provided between the central column 11 of the magnetic core 1 and the central column 21 of the magnetic core 2 , and the inductance coil is wound around the central column 11 of the magnetic core 1 and the central column 21 of the magnetic core 2 .

In the embodiment of the present application, the length of the central column 11 of the magnetic core 1 may be smaller than the length of the two side columns 12, and the length of the central column 21 of the magnetic core 2 may be smaller than the two side columns 22, thereby forming the Gap 3. In other examples, only the length of the central column of one of the magnetic cores may be smaller than the length of the two side columns, and the length of the central column of the other magnetic core may be the same as the length of the two side columns.

A structural member is arranged in the gap 3, and the structural member, the central column 11 of the magnetic core 1 and the central column 21 of the magnetic core 2 together form one or more chambers, and the structure of each chamber is The volume of the air contained in the chamber is stretched or compressed by the magnetic field force generated by the central column of the magnetic core during operation.

In this embodiment of the present application, the structural member may be any structure made of a material that does not have electrical conductivity and magnetic permeability, and the function of the structural member is to form one or more cavities with the two core pillars chambers, so that the air contained in each chamber can be stretched or compressed by the magnetic field force generated by the central column of the magnetic core during operation. When the air contained in the chamber is compressed, the air forms a reaction force in order to "resist" being compressed, and when the air is stretched, the air also forms a reaction force in order to "resist" being stretched. The generated reaction force can offset the electromagnetic force generated by the central column 11 of the magnetic core 1 and the central column 21 of the magnetic core 2 during operation, and play a buffering effect on the electromagnetic force, thereby reducing the vibration of the magnetic core and reducing the inductance. Noise generated inside the device.

In a specific example, the air volume contained in the chamber is stretched or compressed by the magnetic field force generated by the central column of the magnetic core during operation, and the structural member is connected to the central column 11 of the magnetic core 1 and the central column of the magnetic core 2. One or more chambers commonly enclosed between the columns 21 may be closed chambers.

As shown in FIG. 3, FIG. 3 is a schematic diagram of a structural member in an example. In FIG. 3, the structural member 4 is annular in shape and is disposed on the surface of the center column 21 of the magnetic core 2. When the magnetic core 1 and the magnetic When the cores 2 are stacked on top of each other in a manner corresponding to the opening positions, the structural member 4, the central column 11 of the magnetic core 1 and the central column 21 of the magnetic core 2 enclose a closed circular area. The interior space is relatively closed to the outside. In a preferred example, the center point of the closed circular area is coincident with the axial centers of the central column 11 of the magnetic core 1 and the central column 21 of the magnetic core 2 .

As shown in FIG. 4 , FIG. 4 is a schematic structural diagram of the magnetic core column 11 , the structural member 4 and the magnetic core central column 21 when the magnetic core 1 and the magnetic core 2 are stacked on top of each other in the example in FIG. 3 . It can be seen that a certain amount of air is enclosed in the annular structural member 4 . This part of the airtight air is used to play the role of buffer force, to do work on the magnetic field force generated by the center column of the magnetic core during operation, and to counteract the force, so as to achieve the purpose of reducing the noise of the magnetic core.

As shown in Figure 5 and Figure 6, Figure 5 and Figure 6 show the principle that the airtight air acts as a buffer force under different working conditions.

In the example of FIG. 5 , when the upper magnetic core 1 generates a downward suction force during operation, due to the airtight air in the annular structural member 4, this part of the air volume will be compressed, and the air will be compressed in order to "resist". It is compressed to form a reaction force and generate an upward supporting force, which will offset the downward force of the magnetic core 1 and play a buffering effect.

In the example of FIG. 6 , when the upper magnetic core 1 generates an upward pulling force during operation, due to the closed air in the annular structural member 4, this part of the air volume will be stretched, and the air will be stretched in order to "resist" It is stretched to form a reaction force and generate a downward suction force, which will cancel the upward force of the magnetic core 1 and play a buffering effect.

In other examples, when the lower magnetic core 2 generates a similar magnetic field force during operation, the air sealed in the annular structural member 4 can have the same buffering effect, which is not repeated here.

In the embodiment of the present application, a structural member is arranged in the gap between the central columns of the two magnetic cores stacked on top of each other, so that one or more cavities are enclosed between the structural member and the central column of the upper and lower magnetic cores The structure of the chamber is such that the volume of the air contained in the chamber is stretched or compressed by the magnetic field force generated by the central column of the magnetic core during operation. "Being compressed to form a reaction force, when the air contained in the chamber is stretched, this part of the air also forms a reaction force in order to "resist" being stretched, and the reaction force generated by the air contained in the above-mentioned chamber can offset the magnetic core. The electromagnetic force generated by the central column of the magnetic core can buffer the electromagnetic force, thereby reducing the vibration of the magnetic core and reducing the noise generated inside the inductance device.

In the examples of FIGS. 3 to 6 , the number of the chambers is one, which is equivalent to that the structural member includes one sub-structural member. In other examples, the structural member may also include a plurality of sub-structural members. A plurality of the cavities are jointly enclosed between the sub-structures and the central pillars of the two magnetic cores.

As shown in FIG. 7 , in the example of FIG. 7 , there are three substructures of annular structure nested in each other, and three cavities are jointly enclosed by the three substructures and the central pillars of the two magnetic cores. For the chambers, preferably, the center point of each chamber coincides with the axes of the central pillars of the two magnetic cores.

In other examples, the number of substructures may also be other, and the shape of the cavity is not limited to a circle, but also a polygon or an irregular shape.

The chamber in the above-mentioned specific example is a closed chamber, and its inner space is closed relative to the outside. When the closed air in the chamber forms a reaction force in order to "resist" being compressed or stretched, when the reaction force is too strong, New noise may be generated, therefore, in a preferred embodiment, the chamber further includes a non-sealed chamber, and the non-sealed chamber is provided with an air inlet channel connected to the outside, so as to be closed in the chamber When the compressed air forms a reaction force in order to "resist" compression, the compressed air can overflow from the non-sealed chamber, and when the closed air in the chamber forms a reaction force in order to "resist" being stretched, the outside air can be timely. Supplement into the unsealed chamber, so that the above reaction force will not be too strong.

In some examples, when the number of chambers includes multiple chambers, all chambers may be sealed chambers, or all chambers may be non-sealed chambers, or some chambers may be sealed chambers, and some chambers may be sealed chambers. It is an unsealed chamber.

In one example, the air inlet channel of the chamber may be a void inside the material of the sub-structure. For example, when the sub-structure is made of foam, foam, sponge and other foam materials, the material inside the sub-structure is There is a large amount of voids that constitute the air intake passages of the chambers.

In other examples, when there is not a large amount of voids within the material of the substructure, the air inlet channel may be a gap formed by the substructure. As shown in FIG. 8 , in FIG. 8 , a ring-shaped substructure 41 is included, and a gap 411 is formed in the substructure. The air inlets of the chambers that are enclosed together. In other examples, the air intake passage may also be a gap between the sub-structure and the central pillars of the two magnetic cores.

When the diameter of the intake passage is too large, the electromagnetic force generated by the air contained in the chamber to counteract the electromagnetic force generated by the central column of the magnetic core during operation will be greatly reduced. Therefore, in one example, the intake passage The width d is smaller than the width D of the structural member enclosing the chamber to which the intake passage belongs. In a preferred example, the ratio between the width d of the intake passage and the width D of the structural member enclosing the chamber to which the intake passage belongs is greater than 1/10 and less than 1/5.

In the embodiment of the present application, when the structural member is made of an inelastic material, the inductance device mainly uses the reaction force formed by the structural member and the air in the cavity enclosed between the two magnetic core columns to cancel the magnetic core. The electromagnetic force generated by the column, in a preferred embodiment, in order to further reduce the vibration and noise caused by the electromagnetic force generated by the column in the magnetic core, the structural member is made of elastic material.

When the structural member is made of an elastic material, the elastic material itself has a buffering effect on the vibration caused by the electromagnetic force, which can reduce the work done by the electromagnetic force on the magnetic core, thereby reducing noise. In combination with the cavity in the embodiment of the present application, when the structural member in the example of FIG. 5 is made of elastic material, when the upper magnetic core 1 generates a downward suction force during operation, the annular structural member 4 There is airtight air, this part of the air volume will be compressed, and the air will form a reaction force in order to "resist" the compression, and generate an upward supporting force, which will cancel the downward force of the magnetic core 1, and at the same time, the upper The magnetic core 1 generates a downward suction force during operation and also compresses the structural member 4, so that the volume of the cavity enclosed by the structural member 4 is reduced, which further compresses the airtight air in the structural member, thereby generating a stronger reaction force. , produce stronger upward support force and play a better buffering effect.

In the example of FIG. 6 , when the upper magnetic core 1 generates an upward pulling force during operation, due to the closed air in the annular structural member 4, this part of the air volume will be stretched, and the air will be stretched in order to "resist" It is stretched to form a reaction force and generate a downward suction force, which will cancel the upward force of the magnetic core 1. At the same time, the upward pulling force of the upper magnetic core 1 will also stretch the structural member 4 during operation. The volume of the cavity enclosed by the structural member 4 is increased, and the airtight air in the structural member is further stretched, thereby generating a stronger reaction force, a stronger downward suction force, and a better buffer effect. .

Preferably, in order to more conveniently fix the structural member between the two magnetic core central pillars, the structural member is made of viscoelastic material, or the structural member is fixed to the gap through a viscous material, in other cases In an example, when the structural member is made of a non-viscoelastic material, it can also be directly placed in the gap.

When the structural member is made of viscoelastic material, the structural member may be epoxy resin glue. In the embodiment of the present application, when the shape of the glue to be dispensed is annular, the amount of glue dispensed each time is better. Compared with the traditional dispensing method, the consistency of dispensing volume will be better.

In the embodiment of the present application, the structural member may be specifically made of high elasticity/plastic materials, various systems/hardness glues, silica gel/rubber system materials, foam/foam/sponge and other foam materials Or TPU and other non-Newtonian fluid materials, the embodiment of the present application does not limit the specific material type.

An embodiment of the present application further provides a method for manufacturing an inductance device, as shown in FIG. 9 , in an exemplary embodiment, the method includes the following steps:

S901: stack the two magnetic cores up and down in a manner corresponding to the opening positions;

S902: Disposing a structural member in the gap between the central pillars of the two magnetic cores, the structural member and the central pillars of the two magnetic cores together form one or more chambers, each of which is The structure of the chamber is such that the volume of the air contained in the chamber is stretched or compressed by the magnetic field force generated by the central column of the magnetic core during operation;

S903: Wind the inductance coil on the center pillars of the two magnetic cores.

In an exemplary embodiment, the structural member includes one or more sub-structural members, and the one or more sub-structural members and the central pillars of the two magnetic cores together enclose one or more of the Chamber.

In an exemplary embodiment, the chamber includes a closed chamber, and the inner space of the closed chamber is closed relative to the outside.

In an exemplary embodiment, the chamber includes a non-hermetic chamber provided with an air inlet channel connected to the outside.

In an exemplary embodiment, the air intake passage is a void within the material of the substructure.

In an exemplary embodiment, the intake passage is a notch formed by the sub-structure.

In an exemplary embodiment, the width of the intake passage is smaller than the width of the structural member that encloses the chamber to which the intake passage belongs.

In an exemplary embodiment, the ratio between the width d of the intake passage and the width D of the structural member enclosing the chamber to which the intake passage belongs is greater than 1/10 and less than 1/5.

In an exemplary embodiment, the shape of the substructure is annular, and when the substructure includes a plurality of substructures, a plurality of the substructures are nested and disposed in the gap.

In an exemplary embodiment, the structural member is made of an elastic material.

In an exemplary embodiment, the structural member is made of viscoelastic material, or the structural member is fixed to the gap by an adhesive material.

In an exemplary embodiment, the structural member is epoxy glue.

It should be understood that the embodiments of the present application are not limited to the precise structures described above and shown in the accompanying drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the embodiments of the present application is limited only by the appended claims.

The above-mentioned embodiments only represent several implementations of the embodiments of the present application, and the descriptions thereof are relatively specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be noted that, for those of ordinary skill in the art, without departing from the concept of the embodiments of the present application, several modifications and improvements can be made, which all belong to the protection scope of the embodiments of the present application.

Claims (13)

1. An inductive device, comprising:

the inductor comprises an inductance coil and two magnetic cores, wherein the two magnetic cores are vertically superposed in a way that the opening positions correspond to each other, and the inductance coil is wound on the middle columns of the two magnetic cores;

the magnetic core structure comprises two magnetic cores and is characterized in that a gap is formed between the center pillars of the two magnetic cores, a structural part is arranged in the gap, one or more chambers are enclosed between the structural part and the center pillars of the two magnetic cores, and the volume of air contained in each chamber is stretched or compressed by magnetic field force generated by the center pillars of the magnetic cores in working.

2. The inductive device of claim 1, wherein:

the structural part comprises one or more sub-structural parts, and one or more cavities are enclosed between the one or more sub-structural parts and the center pillars of the two magnetic cores.

3. The inductive device of claim 2, wherein:

the chamber comprises a closed chamber, and the inner space of the closed chamber is closed relative to the outside.

4. The inductive device of claim 2, wherein:

the chamber comprises a non-closed chamber, and the non-closed chamber is provided with an air inlet channel connected with the outside.

5. The inductive device of claim 4, wherein:

the air inlet channel is a gap inside the substructure material.

6. The inductive device of claim 4, wherein:

the air inlet channel is a gap formed by the sub-structural part.

7. The inductive device of claim 6, wherein:

the width of the air inlet channel is smaller than that of a structural member which encloses the chamber of the air inlet channel.

8. The inductive device of claim 7, wherein:

the ratio of the width D of the air inlet channel to the width D of the structural member enclosing the cavity of the air inlet channel is greater than 1/10 and less than 1/5.

9. The inductive device of claim 2, wherein:

the shape of the substructure is annular, and when the substructure comprises a plurality of substructures, the plurality of substructures are nested and arranged in the gap.

10. An inductive device according to any one of claims 1 to 9, characterized in that:

the structural member is made of an elastic material.

11. The inductive device of claim 10, wherein:

the structural member is made of a viscoelastic material, or the structural member is fixed to the gap by a viscous material.

12. The inductive device of claim 11, wherein:

the structural member is epoxy resin glue.

13. A method of manufacturing an inductive device, comprising the steps of:

superposing the two magnetic cores up and down in a way that the opening positions correspond;

arranging a structural member in a gap between the center pillars of the two magnetic cores, wherein the structural member and the center pillars of the two magnetic cores jointly enclose one or more chambers, and each chamber is structured such that the volume of air contained in the chamber is stretched or compressed by the magnetic field force generated by the center pillars of the magnetic cores in operation;

and winding an inductance coil around the center posts of the two magnetic cores.

Images