Reactor

• US 8,279,035 B2
• Filed: 02/26/2010
• Issued: 10/02/2012
• Est. Priority Date: 03/25/2009
• Status: Expired due to Fees

• Current Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Original Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Inventors: Yoshikawa, Kouhei, Katou, Masayuki, Itou, Atsushi, Yamamoto, Shinichiro, Kawaguchi, Hajime
• Primary Examiner(s): NGUYEN, TUYEN T
• Application Number:
  US13/259,658
• Publication Number:
  US 20120092120A1
• Time in Patent Office: 949 Days
• Field of Search: 336/55, 336/62, 336/65, 336/90, 336/92, 336/96, 336/212, 336/219
• US Class Current: 336/96
• CPC Class Codes: H01F 2017/046 helical coil made of flat wire, e.g. with smaller extension of wire cross section in the direction of the longitudinal axis
• CPC Class Codes: H01F 27/022 Encapsulation
• CPC Class Codes: H01F 27/06 Mounting, supporting or suspending transformers, reactors or choke coils not being of the signal type
• 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 3/14 Constrictions; Gaps, e.g. air-gaps in magnetic shunt paths H01F3/12
• CPC Class Codes: H01F 37/00 Fixed inductances not covered by group H01F17/00

Abstract

A compact reactor with excellent productivity and heat dissipation is provided. Reactor 1α includes a coil formed by spirally winding a wire 2w and a magnetic core 3 having an inside core portion inserted into the coil and an outside core portion 32 coupled to the inside core portion. These core portions form a closed magnetic circuit. The coil is covered with an inside resin portion 4 on the outer circumference thereof to form a coil molded unit 20α with its shape being held. The outer circumference of a combination unit 10 of the coil molded unit 20α and the magnetic core 3 is covered with an outside resin portion 5α. Reactor 1α does not have a case and is thus compact. A surface of the outside core portion 32 on the installation side (core installation surface 32d) is exposed form the outside resin portion 5α and is in direct contact with a fixed object, thereby achieving excellent heat dissipation. The provision of the coil molded unit 20α facilitates the handling of the coil during assembly of reactor 1α, thereby achieving good productivity.

Claims

1. A reactor including a coil formed by spirally winding a wire, and a magnetic core having an inside core portion inserted into said coil and an outside core portion coupled to the inside core portion to form a closed magnetic circuit, comprising:

a coil molded unit having said coil and an inside resin portion covering an outer circumference of said coil to hold its shape; and

an outside resin portion covering at least part of an outer circumference of a combination unit of said coil molded unit and said magnetic core,

wherein a surface of said outside core portion that serves as an installation side when said reactor is installed protrudes from a surface of said inside core portion that serves as an installation side, and is exposed from said outside resin portion,

said inside resin portion has an interposed resin portion interposed between said coil and said inside core portion, and

said reactor further comprises a cushion member which is interposed between said interposed resin portion and said inside core portion and does not cover said outside core portion.

2. The reactor according to claim 1, further comprising a positioning portion which is integrally formed in said inside resin portion and is used for positioning said combination unit with respect to a molding die when said outside resin portion is formed using a molding die,

wherein at least part of said positioning portion is not covered with said outside resin portion.

3. The reactor according to claim 2, wherein

said coil includes a pair of coil elements and a coil coupling portion coupling the coil elements with each other,

said coil coupling portion is provided to protrude from a turn formation surface of said coil elements, and

said positioning portion is formed at a portion that covers said coil coupling portion in said inside resin portion.

4. The reactor according to claim 2, wherein said positioning portion is formed only with constituent resin of said inside resin portion.

5. The reactor according to claim 1, further comprising a notched corner portion formed at a ridge line formed by an inner end surface of said outside core portion that is opposed to an end surface of said coil molded unit and an adjacent surface connected to the inner end surface, for introducing constituent resin of said outside resin portion into between the end surface of said coil molded unit and the inner end surface of said outside core portion.

6. The reactor according to claim 1, wherein a surface of said outside core portion that serves as an installation side when said reactor is installed and a surface of said coil molded unit that serves as an installation side are coplanar, and these surfaces are exposed from said outside resin portion.

7. The reactor according to claim 1, wherein said coil includes a pair of coil elements, said coil elements being arranged side by side such that axial directions thereof are parallel with each other, and

said inside resin portion has a depression at a portion that covers a gap between said coil elements and that serves as an installation side when said reactor is installed.

8. The reactor according to claim 1, wherein a constituent material of said cushion member has Young'"'"'s modulus smaller than constituent resin of said inside resin portion.

9. The reactor according to claim 1, wherein said cushion member is at least one kind selected from a heat-shrinkable tube, a cold-shrinkable tube, a mold layer, a coating layer, and a tape winding layer.

10. The reactor according to claim 1, wherein a gap of not less than 0.5 mm and not more than 4 mm is formed between an inner end surface of said outside core portion that is opposed to an end surface of said coil molded unit and the end surface of said coil molded unit, and constituent resin of said outside resin portion is present in this gap.

11. A reactor including a coil formed by spirally winding a wire, and a magnetic core having an inside core portion inserted into said coil and an outside core portion coupled to the inside core portion to form a closed magnetic circuit, comprising:

a coil molded unit having said coil and an inside resin portion covering an outer circumference of said coil to hold its shape; and

an outside resin portion covering at least part of an outer circumference of a combination unit of said coil molded unit and said magnetic core, wherein

a surface of said outside core portion that serves as an installation side when said reactor is installed protrudes from a surface of said inside core portion that serves as an installation side, and is exposed from said outside resin portion,

said reactor further comprises a positioning portion which is integrally formed in said inside resin portion and is used for positioning said combination unit with respect to a molding die when said outside resin portion is formed using a molding die, and

at least part of said positioning portion is not covered with said outside resin portion.

12. The reactor according to claim 11, further comprising a notched corner portion formed at a ridge line formed by an inner end surface of said outside core portion that is opposed to an end surface of said coil molded unit and an adjacent surface connected to the inner end surface, for introducing constituent resin of said outside resin portion into between the end surface of said coil molded unit and the inner end surface of said outside core portion.

13. The reactor according to claim 12, wherein said notched corner portion is formed by rounding said ridge line.

14. The reactor according to claim 11, wherein a surface of said outside core portion that serves as an installation side when said reactor is installed and a surface of said coil molded unit that serves as an installation side are coplanar, and these surfaces are exposed from said outside resin portion.

15. The reactor according to claim 11, wherein said coil includes a pair of coil elements, said coil elements being arranged side by side such that axial directions thereof are parallel with each other, and

said inside resin portion has a depression at a portion that covers a gap between said coil elements and that serves as an installation side when said reactor is installed.

16. The reactor according to claim 11, wherein

said coil includes a pair of coil elements and a coil coupling portion coupling the coil elements with each other,

said coil coupling portion is provided to protrude from a turn formation surface of said coil elements, and

said positioning portion is formed at a portion that covers said coil coupling portion in said inside resin portion.

17. The reactor according to claim 11, wherein said positioning portion is formed only with constituent resin of said inside resin portion.

18. The reactor according to claim 11, wherein a gap of not less than 0.5 mm and not more than 4 mm is formed between an inner end surface of said outside core portion that is opposed to an end surface of said coil molded unit and the end surface of said coil molded unit, and constituent resin of said outside resin portion is present in this gap.

19. A reactor including a coil formed by spirally winding a wire, and a magnetic core having an inside core portion inserted into said coil and an outside core portion coupled to the inside core portion to form a closed magnetic circuit, comprising:

a coil molded unit having said coil and an inside resin portion covering an outer circumference of said coil to hold its shape; and

an outside resin portion covering at least part of an outer circumference of a combination unit of said coil molded unit and said magnetic core,

wherein a surface of said outside core portion that serves as an installation side when said reactor is installed protrudes from a surface of said inside core portion that serves as an installation side, and is exposed from said outside resin portion, and

said reactor further comprises a notched corner portion formed at a ridge line formed by an inner end surface of said outside core portion that is opposed to an end surface of said coil molded unit and an adjacent surface connected to the inner end surface, for introducing constituent resin of said outside resin portion into between the end surface of said coil molded unit and the inner end surface of said outside core portion.

20. The reactor according to claim 19, wherein a surface of said outside core portion that serves as an installation side when said reactor is installed and a surface of said coil molded unit that serves as an installation side are coplanar, and these surfaces are exposed from said outside resin portion.

21. The reactor according to claim 19, wherein said coil includes a pair of coil elements, said coil elements being arranged side by side such that axial directions thereof are parallel with each other, and

said inside resin portion has a depression at a portion that covers a gap between said coil elements and that serves as an installation side when said reactor is installed.

22. The reactor according to claim 19, wherein said notched corner portion is formed by rounding said ridge line.

23. The reactor according to claim 19, wherein a gap of not less than 0.5 mm and not more than 4 mm is formed between an inner end surface of said outside core portion that is opposed to an end surface of said coil molded unit and the end surface of said coil molded unit, and constituent resin of said outside resin portion is present in this gap.