Magnetic core for inductor

• US 6,897,754 B2
• Filed: 06/05/2002
• Issued: 05/24/2005
• Est. Priority Date: 07/25/2001
• Status: Expired due to Fees

• Current Assignee: Abov Semiconductor Co., Ltd., Tokyo Coil Engineering Co., Ltd.
• Original Assignee: PULSUS Technologies, Inc., Tokyo Coil Engineering Co., Ltd.
• Inventors: Ishikawa, Michio, Koo, Jin Wook, Jeong, Bong Soo
• Primary Examiner(s): Nguyen, Tuyen T.
• Application Number:
  US10/163,887
• Publication Number:
  US 20030020580A1
• Time in Patent Office: 1,084 Days
• Field of Search: 336/65, 336/83, 336/178, 336/198, 336/200, 336210-212, 336/216, 336/221, 336/233, 336/234
• US Class Current: 336/83
• CPC Class Codes: H01F 17/043 with two, usually identical or nearly identical parts enclosing completely the coil (pot cores)
• CPC Class Codes: H01F 17/045 with core of cylindric geometry and coil wound along its longitudinal axis, i.e. rod or drum core
• CPC Class Codes: H01F 27/027 specially adapted for combination of signal type inductors or transformers with electronic circuits, e.g. mounting on printed circuit boards
• CPC Class Codes: H01F 3/14 Constrictions; Gaps, e.g. air-gaps in magnetic shunt paths H01F3/12

Abstract

Disclosed is a low-priced and small-sized magnetic core for an inductor suitable for a high frequency signal and a large-current signal. The magnetic core is modified from a conventional EP type magnetic core. A recess is integrally formed with a peripheral portion of the magnetic core when it is shaped. A bottom portion and the peripheral portion are extended toward an opening portion to an extent of about 70 percentages of a length measured from a center of the center portion to an internal surface of the peripheral portion. The peripheral portion opposite to the opening portion has a uniform thickness. The magnetic core is designed to facilitate its surface mounting onto a PCB.

Claims

1. An EPS type magnetic core, an improvement of EP type magnetic core, for an inductor, comprising a center portion, a peripheral portion, a bottom portion, and an opening portion:

wherein the bottom portion and the peripheral portion form a partial enclosure for housing the center portion, the center portion being located on the bottom portion, the peripheral portion extending partially around the center portion to form two generally straight end segments with an arcuate segment therebetween, the arcuate segment extending about approximately half of the center portion and being spaced a predetermined distance from a center of the center portion, the two generally straight end segments, in combination with the bottom portion define the opening portion, a distance from the center of the center portion to the opening portion being about seventy percent of the predetermined distance.

2. The EPS type magnetic core as claimed in claim 1, wherein the peripheral portion opposite to the opening portion has a uniform thickness.

3. The EPS type magnetic core as claimed in claim 2, wherein the thickness of the peripheral portion is constant all over, the peripheral portion being extended toward the opening portion is in a straight line in parallel to each other, and the peripheral portion opposite to the opening portion has a semicircular shape.

4. The EPS type magnetic core as claimed in claim 3, wherein the peripheral portion directly opposite to the opening portion has a flat surface formed on an outer circumference thereof.

5. The EPS type magnetic core as claimed in claim 1, wherein the center portion is ground to a predetermined depth to form an air gap, such that the EPS type magnetic core is used for a large-current signal and a high-frequency signal.

6. The EPS type magnetic core as claimed in claim 5, wherein the EPS type magnetic core is used for a digital audio amplifier.

7. The EPS type magnetic core as claimed in claim 1, further comprising a recess formed in a predetermined position of the peripheral portion, wherein the position in which the recess is located is opposite to the opening portion, and the recess has a width more than or equal to a diameter of the center portion, and a depth more than a depth of the center portion being ground.

8. The EPS type magnetic core as claimed in claim 7, wherein the recess is formed in the peripheral portion which is integrally formed with the center portion and the bottom portion.

9. The EPS type magnetic core as claimed in claim 7, wherein the EPS type magnetic core is used for a digital audio amplifier.

10. A magnetic core for an inductor, having a center portion, a peripheral portion, and a bottom portion, two magnetic cores being opposite and coupled to each other to form one inductor, the center portion being wound by a coil when forming the inductor, being ground to form an air gap, and forming a magnetic path through which magnetic flux generated during operation of the inductor flows, the peripheral portion surrounding the center portion, the bottom portion which couples the center portion to the peripheral portion forming the magnetic path to prevent the magnetic flux from leaking out of the inductor, and the coil being inserted into a space defined by the center portion, the peripheral portion, and the bottom portion, the magnetic core comprising:

at least one recess located in an edge of the peripheral portion having a width larger than or equal to a diameter of the center portion and a an edge closer to the bottom portion than a top of the center portion being ground to facilitate grinding of the center portion, and integrally formed with the center portion, bottom portion and peripheral portion.

13. The magnetic core as claimed in claim 10, wherein the center portion is ground.

11. A magnetic core for an inductor, the magnetic core having a center portion, a peripheral portion, a bottom portion, and an opening portion, two magnetic cores being opposite and coupled to each other to form one inductor, the center portion being wound by a coil when forming the inductor, being ground to form an air gap, and forming a magnetic path through which magnetic flux generated during operation of the inductor flows, the peripheral portion surrounding the center portion, the bottom portion which couples the center portion to the peripheral portion forming the magnetic path to prevent the magnetic flux from leaking out of the inductor, the coil being inserted into a space defined by the center portion, the peripheral portion, and the bottom portion, and the opening portion being a portion from which the peripheral portion is removed, the magnetic core comprising:

a recess located in an edge of the peripheral portion opposite to the opening portion, the recess having a width larger than or equal to a diameter of the center portion and having an edge closer to the bottom portion than a top of the center portion being ground, and integrally formed with the center portion, bottom portion and peripheral portion.

12. The magnetic core as claimed in claim 11, wherein the magnetic core comprises an EP type magnetic core.