Method of producing a surface-mount inductor

• US 8,695,209 B2
• Filed: 04/09/2010
• Issued: 04/15/2014
• Est. Priority Date: 04/10/2009
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: TOKO Incorporated (Murata Manufacturing Co Limited)
• Inventors: Saito, Koichi, Sakai, Chitoshi
• Primary Examiner(s): Vo, Peter DungBa
• Assistant Examiner(s): Carley, Jeffrey T
• Application Number:
  US12/757,644
• Publication Number:
  US 20100259353A1
• Time in Patent Office: 1,467 Days
• Field of Search: 296/021, 296/04, 29607-609, 298/32, 298/41, 298/25, 298/29, 298/46, 336/83, 336/96, 336/197, 336/199, 336/200, 336/205, 336/208, 439/620.09, 439/620.13, 439/55, 257/787, 438/478, 438/481, 438/41, 438/341, 438/388, 438/328, 438/25, 438/26, 438/105, 438125-127
• US Class Current: 29/602.1
• CPC Class Codes: H01F 2017/048 with encapsulating core, e.g. made of resin and magnetic powder
• CPC Class Codes: H01F 27/292 Surface mounted devices
• CPC Class Codes: H01F 27/327 Encapsulating or impregnating encapsulating coil and core H01F27/022
• CPC Class Codes: H01F 41/005 Impregnating or encapsulating insulating of windings H01F41/12
• CPC Class Codes: H01F 41/127 Encapsulating or impregnating encapsulating coil and core H01F41/005
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49069 Data storage inductor or core
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49146 with encapsulating, e.g., potting, etc.

Abstract

A method of producing a surface-mount inductor by encapsulating a coil with an encapsulation material containing a resin and a filler using a mold die assembly is provided. In the method, a tablet and a coil are used. The tablet is prepared by preforming the encapsulation material into a shape having a flat plate-shaped portion and a pillar-shaped convex portion on a peripheral thereof. The coil is a wound conductive wire having a cross-section of rectangular-shape. The coil is placed on the tablet to allow both ends of the coil to extend along an outer side surface of the pillar-shaped convex portion of the tablet. The coil and the encapsulation material are integrated together while clamping the both ends of the coil between an inner wall surface of the mold die assembly and the outer side surface of the pillar-shaped convex portion of the tablet, to form a molded body. External electrodes are formed on a surface of or around an outer periphery of the molded body in such a manner that the external electrodes are electrically connected to the both ends of the coil at least a portion of which is exposed to the surface of the molded body.

Claims

1. A method of producing a surface-mount inductor by encapsulating a coil with an encapsulation material containing a resin and a filler using a mold die assembly, said method comprises the steps of:

preparing a first tablet by preforming a part of the encapsulation material, the first tablet is prepared such that it has a flat portion formed such that it has a plate shape and a convex portion formed such that it has a pillar shape on a peripheral of the flat portion;

preparing the coil by winding conductive wire having a rectangular cross-section to form an air-core coil;

placing the air-core coil on the flat portion of the first tablet to allow both ends of the air-core coil to extend along an outer side surface of the convex portion of the first tablet, and disposing the air-core coil and the first tablet in the mold die assembly such that the both ends of the air-core coil are clamped between an inner wall surface of the mold die assembly and the outer side surface of the convex portion of the first tablet;

loading a second tablet prepared with the rest of the encapsulation material into the mold die assembly;

integrating the first tablet, the air-core coil and the second tablet together by using a resin molding process or a powder molding process while clamping the both ends of the air-core coil between the inner wall surface of the mold die assembly and the outer side surface of the convex portion of the first tablet, to form a molded body such that at least portions of the ends of the air-core coil are exposed to the surface of the molded body; and

forming external electrodes on a surface of or around an outer periphery of the molded body in such a manner that the external electrodes are electrically connected to the both ends of the coil at least a portion of which is exposed to the surface of the molded body.

2. The method as defined in claim 1, wherein the resin of the encapsulation material includes a thermosetting resin, and wherein the first tablet is preformed in an unset or half-set state.

3. The method as defined in claim 1, wherein the first tablet is formed such that the tablet has a plurality of the pillar-shaped convex portions.

4. The method as defined in claim 1, wherein the filler comprises a magnetic material.