Base of an inductor

A base of an inductor is provided. The inductor comprises an annular body, which has a hollow shaft portion and a surrounding sensing portion. The base comprises a bottom portion, a recess, and a hanging shelf. The recess is formed on the bottom portion. The hanger comprises a transverse shaft, disposed at the central portion of the hanging shelf and adapted to pass through the hollow shaft. When the lower portion of the hanging shelf is fixed in the recess, at least a portion of the peripheral induction portion of the annular body is adapted to rest in the recess.

This application claims priority to P.R. CHINA Patent Application No. 200720176954.3 filed on Oct. 6, 2007, the disclosures of which are incorporated herein by reference in their entirety.

CROSS-REFERENCES TO RELATED APPLICATIONS

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a base of an inductor, and particularly, relates to a base of a filter inductor that facilitates the installation of the filter inductor and maintains a certain distance from a coil and an iron core of the inductor.

2. Descriptions of the Related Art

The rapid development of modern science and technologies has resulted in the widespread use of electric appliances and various electronic communication apparatuses. Nowadays, such products are becoming smaller and multifunctional, adding more need for denser and sophisticated electronic elements. In order to obviate the electromagnetic interference (EMI) between the individual electronic elements and the consequent interference with the overall performance of the products, these products all have to be equipped with a filter inductor to filter out the high-frequency noises by means of the electromagnetic induction effect.

As previously described, the modern electronic and communication products are evolving towards miniaturized ones, and the perspective views of an existing filter inductor adopted in these products are depicted inFIGS. 1A,1B and1C respectively.FIG. 1Ais a perspective view of the bottom portion of the filter inductor, andFIGS. 1B and 1Care perspective front views thereof at the same viewing angle. Particularly,FIG. 1Cdepicts the inductor with a coil wound thereon.

As shown inFIG. 1A, the inductor1is fixed onto a base101by inserting fixing pins103thereof into the base101. Also, shown inFIGS. 1B and 1C, when the coil105of the inductor1is led through the recesses107, wound on the fixing pins103and then soldered thereon, a rugged surface is formed on the base101of the inductor1. Consequently, if the fixing pins103on the bottom of the inductor101are inserted into the through-holes formed in a printed circuit board (PCB; not shown), the inductor will become unstable. For this reason, the four additional bosses109of a certain height have to be formed on the bottom surface to control the height of the base101. However, although this method may prevent the instability of the inductor1, the bosses109disposed on the four bottom edges of the base101inevitably increase the overall height of the inductor1, thus increasing the size of the inductor1.

On the other hand, the other side of the base101opposite the bottom surface thereof serves as the mounting surface111for the inductor1, which is generally planar. Since the distance that is kept between the iron core113and the coil105of the inductor cannot be reduced, the overall height of the inductor1is further increased indirectly, which contradicts the tendency in this industry towards increasingly miniaturized products. Furthermore, the planar mounting surface111may also render the safety distance between the coil105and the bottom of the iron core113to be relatively short, which is disadvantageous for a normal operation.

Additionally, in the prior art, there are two baffles115that are further disposed between the iron core113and the coil105. When the iron core113has a smaller size while the coil105has a bigger size, it would be difficult to assemble the iron core113and the coil105together due to the restriction imposed by the two baffles115. In this case, the coil105would form a tight fit with the base101, leading to a decreased efficiency of the inductor1.

Furthermore, to meet the requirements of safety regulations, an adequate distance shall be kept between the coil105and the bottom of the iron core113. Generally, a minimum distance of 1.6 mm is required therebetween. However, due to the baffles115disposed between the led out coil105aand the iron core113, the conventional inductor1fails to provide such an adequate distance and therefore is deficient in terms of safety performance.

To summarize, the bases of the conventional inductors have an excessively large volume, are unstably fixed and lack an inadequate safety distance between the coil and the iron core. Therefore, it is highly desirable in the art to provide a base of an inductor that allows it to be more stably fixed and to keep a satisfactory safety distance between the coil and the iron core.

SUMMARY OF THE INVENTION

One objective of this invention is to provide a base of an inductor that has a lowered height and decreased overall size, facilitates the fixation by soldering, and enlarges the safety distances for a coil and the bottom of an iron core of the inductor to overcome the disadvantages of the prior art solutions.

A technical solution of this invention is as follows: a base of an inductor, wherein the inductor comprises an annular body with a hollow shaft portion and a peripheral induction portion. The base comprises a bottom portion, a recess, a hanging shelf and at least one fixing pin. The recess is formed on the bottom portion, and at least one inward recess portion is formed on the other side of the bottom portion. The hanging shelf has a transverse shaft portion disposed in a central portion of the hanging shelf and adapted to be inserted in the hollow shaft portion. When a lower portion of the hanging shelf is fixed in the recess, at least one portion of the peripheral induction portion of the annular body extends into the recess. At least one fixing pin extends downward from an interior of the at least one inward recess portion.

Because the fixing pins of this invention are depressed into the bottom portion of the base with an inductor extending into the recess of the base, the structure described above is able to control the overall height of the inductor effectively. Furthermore, an inclined surface defining at least one sidewall of the recess guarantees a safety distances for the coil and the bottom of the iron core, thus enhancing the safety performance of the inductor. The sidewalls in the depression for the fixing pins and the sidewalls of the base cooperate with each other to form an inward recess portion which is reserved as the soldering groove. Thus, the leads of the coil are controlled to not protrude out of the base after being soldered, thereby to effectively control the overall height of the inductor to fulfilling the need for miniaturization. Moreover, the recess further facilitates the installation of the inductor, thus increasing the assembling efficiency and lowering the manufacturing cost.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment of this invention is an inductor assembly2, and an exploded perspective view of which is depicted inFIG. 2A. The inductor assembly2comprises an inductor21and a base23. The inductor21is a filter inductor while the base23is a supporting base to support the filter inductor. The inductor21comprises an annular body, which has a hollow shaft portion201and a peripheral induction portion203. The base23has a bottom portion231, a recess233, a hanging shelf235and four fixing pins237.

In this embodiment, the peripheral induction portion203of the inductor21consists of the two semicircular housings203a,203band a coil203c. Upon assembly, the semicircular housings203a,203bare adapted to define a hollow shaft portion201therebetween to form the aforesaid annular body. Furthermore, after the semicircular housings203a,203bare assembled together, at least one annular groove203dis formed on the housing to allow the coil203cto be wound therein. In this embodiment, a copper wire may be used for the coil.

As depicted inFIG. 2C, the two opposite sides of the bottom portion231are formed with two symmetric inward recess portions231arespectively. In this embodiment, each of the inward recess portions231ais formed by penetrating through a section of the side of the base23and further forming a recess on the bottom surface of the base23near the penetrating portion.

The recess233is formed downwardly on the bottom portion of the base23, and the sidewall of the recess233is defined by an inclined surface to further match a profile of the peripheral induction portion203of the inductor21. Although only a simple inclined surface is used to match the arc profile at the bottom of the peripheral induction portion203in this embodiment, the inclined surface may also be formed into a concave arc profile to enlarge the spacing between this inclined surface and the peripheral induction portion203in other embodiments. Furthermore, both sides of the recess233are adapted to match the bottom portion of the hanging shelf235.

To fix the inductor assembly2onto a circuit board (not shown), the base23also comprises four fixing pins237for fixing purpose. As the two opposite sides of the bottom portion231are formed with two symmetric inward recess portions231a, the four fixing pins237are allowed to extend downward from the interior of either the inward recess portions231a. It should be noted that the number of the fixing pins237is not just limited to what is described above. Similarly, the locations and the arrangement of the fixing pins237are not just limited to the aspects described in the above embodiment. Accordingly, the locations and the number of the inclination surfaces of the recess233and the inward recess portions231aare not just limited thereto. For example, the inclination surfaces may also be formed on both sides of the recess233.

The hanging shelf235has a traverse shaft portion235aformed in the central portion of the hanging shelf235and adapted for insertion into the hollow shaft portion201. When the lower portion of the hanging shelf235is inserted in the recess233, at least one portion of the peripheral induction portion203of the annular body is adapted to extend into the recess233. More specifically, the hanging shelf235of this embodiment is a θ-shaped iron core.

The inductor21is inserted into the corresponding mounting slot of the recess233during the assembly, which is a very simple and highly efficient process. Moreover, the installation of the inductor assembly2onto the circuit board simply requires the soldering of the fixing pins237onto the circuit board along the penetrated side of the base23.

In this invention, the bottom portion of the hanging shelf235is surrounded by the recess233of the bottom portion of the base23, thereby considerably enlarging the safe distance from the bottom portion of the hanging shelf235to the inductor21. Furthermore, the fixing pins237are led out through the inward recess portions231a, and the portions of the coil203cwound to the fixing pins237are adapted to be concealed within the inward recess portions231a. Therefore, after being soldered to the fixing pin237, the coil203cwill not protrude from the base23and thus will not contribute to the height of the bottom portion of the base23. In this way, the base23of this invention can be effectively controlled in the overall height, and the fixing pins237of the inductor assembly2can be fixed onto a circuit board without the use of bosses to further meet the needs of this industry for the miniaturization of the inductor assembly2.