Electric contact device

• US 20060128177A1
• Filed: 11/18/2005
• Published: 06/15/2006
• Est. Priority Date: 05/20/2003
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Satoh, Yoshio, Nakatani, Tadashi, Miyashita, Tsutomu, Wakatsuki, Noboru, Yonezawa, Yu
• Granted Patent: US 7,129,434 B2
• Time in Patent Office: Days
• US Class Current: 439/67
• CPC Class Codes: H01H 1/0036 Switches making use of microelectromechanical systems [MEMS] for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009
• CPC Class Codes: H01H 9/40 Multiple main contacts for the purpose of dividing the current through, or potential drop along, the arc
• CPC Class Codes: H01H 9/42 Impedances connected with contacts

Abstract

An electrical contact device (X1) includes a first contactor with contact portions (C1, C2) and a second contactor with contact portions (C3, C4). The device (X1) also includes an electrical circuit having a branch path (YA) provided by the contact portions (C1, C3) and a branch path (YB) provided by the contact portions (C2, C4). When closed, the branch path (YA) has a smaller resistance, and the branch path (YB) a greater resistance. In a closing operation, the first and second contactors approach each other. Then the contact portion (C1) and the contact portion (C3) contact with each other after the contact portion (C2) and the contact portion (C4) contact with each other. In an opening operation, the first and second contactors separate from each other. Then the contact portion (C1) and the contact portion (C3) separate after the contact portion (C2) and the contact portion (C4) separate.

Claims

1. An electrical contact device comprising:

a first contactor including a first contact portion and a second contact portion;

a second contactor including a third contact portion facing the first contact portion and a fourth contact portion facing the second contact portion; and

an electrical circuit including a first branch path and a second branch path disposed in parallel to each other, the first branch path having a first electrical contact provided by the first contact portion and the third contact portion, the second branch path having a second electrical contact provided by the second contact portion and the fourth contact portion, the first branch path having a smaller resistance in a closed state of the first electrical contact, the second branch path having a greater resistance in a closed state of the second electrical contact,

wherein the first contact portion and the third contact portion make contact with each other after the second contact portion and the fourth contact portion make contact with each other in a closing operation in which the first contactor and the second contactor come closer to each other, and the second contact portion and the fourth contact portion come apart from each other after the first contact portion and the third contact portion come apart from each other in an opening operation in which the first contactor and the second contactor move away from each other.

2. The electrical contact device according to claim 1, wherein the first contact portion is spaced from the third contact portion by a distance greater than a distance between the second contact portion and the fourth contact portion, in an open state where the first electrical contact is in an open state and the second electrical contact is in an open state.

3. The electrical contact device according to claim 1, wherein the second branch path includes a resistor with a greater resistance than a contact resistance of the second electrical contact, the resistor being placed in series with the second electrical contact.

4. The electrical contact device according to claim 1, wherein the second electrical contact has a contact resistance which is greater than a contact resistance of the first electrical contact.

5. The electrical contact device according to claim 1, wherein the second contact portion or the fourth contact portion is made of a metal, an oxide or a nitride each including a metal element selected from a group consisting of Ta, W, C and Mo.

6. The electrical contact device according to claim 1, wherein the third contact portion and the fourth contact portion are included in one flat-surface electrode.

7. An electrical contact device comprising:

a first contactor including a plurality of first contact portions and a plurality of second contact portions;

a second contactor including a plurality of third contact portions each facing one of the first contact portions and a plurality of fourth contact portions each facing one of the second contact portions; and

an electrical circuit including a plurality of first branch paths and a plurality of second branch paths disposed in parallel to each other, each of the first branch paths including a first electrical contact provided by the first contact portion and the third contact portion, each of the second branch paths including a second electrical contact provided by the second contact portion and the fourth contact portion, each of the first branch paths having a relatively small resistance in a closed state of the first electrical contact, each of the second branch paths having a relatively large resistance in a closed state of the second electrical contact,

wherein the first contact portions and the third contact portions of all the first electrical contacts make contact with each other after the second contact portions and the fourth contact portions of all the second electrical contacts make contact with each other in a closing operation in which the first contactor and the second contactor come closer to each other, and the second contact portions and the fourth contact portions of all the second electrical contacts come apart from each other after the first contact portions and the third contact portions of all the first electrical contacts come apart from each other in an opening operation in which the first contactor and the second contactor move away from each other.

8. The electrical contact device according to claim 7, wherein each of the first contact portions is spaced from the respective one of the third contact portion by a distance greater than a distance between any one of the second contact portions and the respective one of the fourth contact portions, in an open state in which all of the first electrical contacts are in an open state and all of the second electrical contacts are in an open state.

9. The electrical contact device according to claim 7, wherein each of the second branch paths includes a resistor with a greater resistance than a contact resistance of the respective one of the second electrical contacts, the resistor being placed in series with the respective one of the second electrical contacts.

10. The electrical contact device according to claim 7, wherein each of the second electrical contacts has a contact resistance being greater than a contact resistance of any one of the first electrical contacts.

11. The electrical contact device according to claim 7, wherein at least either all of the second contact portions or all of the fourth contact portions are made of a metal, an oxide or a nitride each including a metal element selected from a group consisting of Ta, W, C and Mo.

12. The electrical contact device according to claim 7, wherein the first contactor includes:

a base having a first surface and a second surface opposite to the first surface;

a plurality of projections each provided on the first surface of the base and each having a tip provided by the first contact portion; and

a first flat-surface electrode provided on the first surface and including a plurality of the second contact portions;

the second contactor having a second flat-surface electrode including a plurality of the third contact portions and a plurality of the fourth electrode portions each being contactable respectively by the tips of the projections and the first flat-surface electrode.

13. The electrical contact device according to claim 12, wherein each of the second branch paths includes a resistor portion with a greater resistance than a contact resistance of the respective one of the second electrical contacts, the resistor portion being placed in series with the respective one of the second electrical contacts, the resistor portion being incorporated in the base and the projections.

14. The electrical contact device according to claim 13, wherein the base and the projections are made of silicon material, at least the resistor portion in the base and in the projections being doped with impurity.

15. The electrical contact device according to claim 12, wherein the second surface of the base is provided with a common electrode for electrical connection with a plurality of the resistor portions.

16. The electrical contact device according to claim 12, wherein the base has a flexible structure for each of the electrical contacts to absorb contacting pressure between the first contact portion and the third contact portion in a closed state of the electrical contact.

17. The electrical contact device according to claim 16, wherein the base includes cantilever beams each serving as the flexible structure, the projections being provided on the beams.