PROTECTIVE DEVICE

• US 20120001720A1
• Filed: 01/14/2010
• Published: 01/05/2012
• Est. Priority Date: 01/21/2009
• Status: Active Grant

• Current Assignee: Dexerials Corporation
• Original Assignee: Sony Chemical & Information Device Corporation (Sony Group Corp.)
• Inventors: Kimura, Yuji, Asada, Takahiro, Ohashi, Youzo
• Granted Patent: US 9,153,401 B2
• Time in Patent Office: Days
• US Class Current: 337/297
• CPC Class Codes: H01H 1/5805 Connections to printed circuits for slide switches H01H15/005; for tumbler switches H01H23/006
• CPC Class Codes: H01H 2037/768 characterised by the composition of the fusible material
• CPC Class Codes: H01H 2085/0414 Surface mounted fuses
• CPC Class Codes: H01H 2085/466 with remote controlled forced fusing
• CPC Class Codes: H01H 37/761 with a fusible element forming part of the switched circuit H01H37/767 takes precedence
• CPC Class Codes: H01H 61/02 wherein the thermally-sensitive member is heated indirectly, e.g. resistively, inductively
• CPC Class Codes: H01H 85/046 Fuses formed as printed circuits

Abstract

A protective device is provided that allows a fusible conductor to be fused off quickly in stability at the time of protective operation against over-current or the like. The protective device includes a fusible conductor 13 and an insulation cover 14 mounted on a base substrate 11 to overlie the fusible conductor 13. The fusible conductor, arranged on an insulating base substrate 11 and connected to a power delivery path of equipment to be protected, is fused off by a preset unusual power. The protective device also includes a flux 19 coated on the fusible conductor 13 and provided within the insulation cover 14. The fusible conductor 13 is immobilized on pair electrodes 12 and a conductor layer 17 on the base substrate 11 via a solder paste 20 containing a metal component exhibiting sufficient wettability against the fusible conductor 13 in a fused state. The solder paste 20, arranged on the pair electrodes 12 and the conductor layer 17, is spread more outwardly than the rim of the fusible conductor 13.

Claims

1. A protective device for protecting equipment for protection in case an unusual power is applied to the equipment for protection, comprising:

a fusible conductor arranged on an insulation base substrate and connected to a power supply path for the equipment for protection so that the fusible conductor will be fused off by a preset unusual power;

an insulation cover mounted on the base substrate to overlie the fusible conductor via a preset spacing; and

a flux coated on the surface of the fusible conductor and disposed in the spacing;

the fusible conductor being fused off to break a current path thereof in case the unusual power is applied to the equipment for protection;

wherein

the fusible conductor is secured to a conductor layer and to pair electrodes provided on the base substrate via an electrically conductive paste containing a metal component exhibiting high wettability with respect to the fusible conductor in the fused state;

the electrically conductive paste being spread more outwards on the conductor layer than the rim of the fusible conductor.

2. The protective device according to claim 1, wherein

the melting temperature of the metal component in the electrically conductive paste is lower than that of the fusible conductor.

3. The protective device according to claim 2, wherein

the electrically conductive paste is a solder paste that immobilizes the fusible conductor with respect to the conductor layer and the pair electrodes.

4. The protective device according to claim 2, wherein

the electrically conductive paste is spread more outwardly on the electrodes than the rim of the fusible conductor.

5. The protective device according to claim 3, wherein

even after the solder paste has immobilized the fusible conductor on the surfaces of the electrodes, the solder paste is spread as a flux component of the solder paste is left.

6. The protective device according to claim 2, wherein

the electrically conductive paste is spread radially from the rim of the fusible conductor on the surface of the conductor layer.

7. The protective device according to claim 4, wherein

the electrically conductive paste is spread radially from the rim of the fusible conductor on the surfaces of the electrodes.

8. The protective device according to claim 2, wherein

the electrically conductive paste is spread on the surface of the conductor layer from the rim of the fusible conductor towards the rim of the conductor layer.

9. The protective device according to claim 4, wherein

the electrically conductive paste is spread on the surfaces of the electrodes from the rim of the fusible conductor towards the rims of the electrodes.

10. The protective device according to claim 3, wherein

the insulation cover includes a rib at a mid portion of an inner surface thereof;

the rib holding the flux.