Methods of manufacturing inductors

• US 6,718,625 B2
• Filed: 05/21/2001
• Issued: 04/13/2004
• Est. Priority Date: 05/12/1998
• Status: Expired due to Term

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Ito, Yoichiro, Morimoto, Tadashi, Komatsu, Hiroshi, Yamamoto, Takahiro, Kawabata, Toshio, Shikama, Takashi
• Primary Examiner(s): Arbes, Carl J.
• Assistant Examiner(s): Trinh, Minh
• Application Number:
  US09/861,732
• Publication Number:
  US 20020020052A1
• Time in Patent Office: 1,058 Days
• Field of Search: 296/06, 296/05, 296/021, 296/08, 336/83, 336/192, 336/200, 336/221, 336/233, 336/96, 336/229, 264/123, 264/236
• US Class Current: 29/606
• 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 41/043 by thick film techniques
• CPC Class Codes: H01F 41/046 structurally combined with ferromagnetic material
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49073 by assembling coil and core
• CPC Class Codes: Y10T 29/49075 including permanent magnet or core

Abstract

A method of manufacturing an inductor having a large current capacity which includes a magnetic sintered body formed via wet pressing treatment and a coil assembly disposed within the magnetic sintered body. The coil assembly is defined by a substantially cylindrical magnetic core member which is wound by a coil. Both ends of the coil of the coil assembly are respectively and electrically connected to an input electrode and an output electrode which are respectively disposed on two mutually facing end surfaces of the magnetic sintered body.

Claims

1. A method of manufacturing an inductor, the method comprising the steps of:

preparing a slurry containing a magnetic ceramic material;

introducing the slurry into a mold in which an electrically conductive wire has been placed;

conducting wet pressing treatment of the slurry in the mold to obtain a magnetic molded body containing the electrically conductive wire;

sintering the magnetic molded body containing the electrically conductive wire, so as to form a magnetic sintered body; and

forming, on outer surfaces of the magnetic sintered body, external electrodes electrically connected to end portions of the electrically conductive wire.

2. The method according to claim 1, wherein the slurry includes a raw material powder, water, a dispersing agent, a defoaming agent and a binding agent.

3. The method according to claim 1, wherein the magnetic sintered body is formed and arranged so as to function as a magnetic path allowing the passing of a magnetic flux generated by the electrically conductive wire.

4. The method according to claim 1, wherein during the wet pressing treatment step, the slurry is pressed and a water component of the slurry escapes so as to form the magnetic molded body and so as to prevent formation of air bubbles in the slurry.

5. The method according to claim 1, wherein the magnetic sintered body has a shape that is substantially rectangular parallelepiped.

6. A method of manufacturing an inductor, the method comprising the steps of:

preparing a slurry containing a magnetic ceramic material;

forming a coil assembly having a magnetic core member and an electrically conductive wire wound around the magnetic core member;

placing the coil assembly into a mold;

introducing the slurry into the mold in which the coil assembly has been placed;

performing wet pressing treatment of the slurry in the mold to obtain a magnetic molded body containing the coil assembly;

sintering the magnetic molded body containing the coil assembly, so as to form a magnetic sintered body; and

forming, on outer surfaces of the magnetic sintered body containing the coil assembly, external electrodes electrically connected to end portions of the electrically conductive wire.

7. The method according to claim 6, wherein the slurry includes a raw material powder, water, a dispersing agent, a defoaming agent and a binding agent.

8. The method according to claim 6, further comprising the steps of placing a plurality of the coil assemblies into the mold, placing the plurality of coil assemblies into the mold, introducing the slurry into the mold in which the plurality of coil assemblies have been placed, performing wet pressing treatment of the slurry in the mold to obtain a magnetic molded body containing the plurality of coil assemblies and sintering the magnetic molded body containing the plurality of coil assemblies, so as to form a magnetic sintered body.

9. The method according to claim 8, further comprising the step of providing non-magnetic plates between each of the plurality of coil assemblies.

10. The method according to claim 8, further comprising the step of providing spaces between each of the plurality of coil assemblies.

11. A method of manufacturing an inductor, the method comprising the steps of:

preparing a slurry containing a magnetic ceramic material;

introducing the slurry into a mold;

performing wet pressing treatment of the slurry in the mold to produce a magnetic molded plate;

forming at least one coil assembly having a magnetic core member and an electrically conductive wire wound around the magnetic core member;

fixing the at least one coil assembly on the magnetic molded plate;

putting the magnetic molded plate and the at least one coil assembly fixed thereto into a mold;

introducing the slurry into the mold in which the magnetic molded plate and the at least one coil assembly has been placed;

performing wet pressing treatment of the slurry in the mold with the magnetic molded plate and the at least one coil assembly so as to obtain a magnetic molded body containing the at least one coil assembly;

sintering the magnetic molded body containing the at least one coil assembly to form a magnetic sintered body; and

forming, on outer surfaces of the magnetic sintered body containing the at least one coil assembly, external electrodes electrically connected to end portions of the electrically conductive wire of the at least one coil assembly.

12. The method according to claim 11, wherein the slurry includes a raw material powder, water, a dispersing agent, a defoaming agent and a binding agent.

13. The method according to claim 11, further comprising the steps of fixing a plurality of the coil assemblies onto the magnetic molded plate, placing the magnetic molded plate and plurality of coil assemblies mounted thereon into the mold, introducing the slurry into the mold in which the magnetic molded plate and the plurality of coil assemblies have been placed, performing wet pressing treatment of the slurry in the mold to obtain a magnetic molded body containing the magnetic molded plate and the plurality of coil assemblies and sintering the magnetic molded body containing the plurality of coil assemblies, so as to form a magnetic sintered body.

14. The method according to claim 13, further comprising the step of providing non-magnetic plates between each of the plurality of coil assemblies.

15. The method according to claim 13, further comprising the step of providing spaces between each of the plurality of coil assemblies.

16. A method of manufacturing an inductor, the method comprising the steps of:

preparing a slurry containing a magnetic ceramic material;

introducing the slurry into a mold;

performing wet pressing treatment of the slurry in the mold to produce a magnetic molded plate;

fixing on the magnetic molded plate at least one coil assembly having an electrically conductive wound wire;

placing the magnetic molded plate and the at least one coil assembly fixed thereto into a mold;

introducing the slurry into the mold in which the magnetic molded plate and the at least one coil assembly has been placed;

performing wet pressing treatment of the slurry, the magnetic molded plate and the at least one coil assembly so as to obtain a magnetic molded body containing the at least one coil assembly;

sintering the magnetic molded body containing the at least one coil assembly to form a magnetic sintered body; and

forming, on outer surfaces of the magnetic sintered body containing the at least one coil assembly, external electrodes electrically connected to end portions of the electrically conductive wire of the at least one coil assembly.

17. The method according to claim 16, wherein the slurry includes a raw material powder, water, a dispersing agent, a defoaming agent and a binding agent.

18. The method according to claim 16, further comprising the steps of fixing a plurality of the coil assemblies onto the magnetic molded plate, placing the magnetic molded plate and plurality of coil assemblies mounted thereon into the mold, introducing the slurry into the mold in which the magnetic molded plate and the plurality of coil assemblies have been placed, performing wet pressing treatment of the slurry in the mold to obtain a magnetic molded body containing the magnetic molded plate and the plurality of coil assemblies and sintering the magnetic molded body containing the plurality of coil assemblies, so as to form a magnetic sintered body.

19. The method according to claim 18, further comprising the step of providing non-magnetic plates between each of the plurality of coil assemblies.

20. The method according to claim 18, further comprising the step of providing spaces between each of the plurality of coil assemblies.