Magnetically activated switch having magnetostrictive material

Patent metadata

Field	Value
Publication number	US-10714286-B2
Application number	US-201815989721-A
Country	US
Kind code	B2
Filing date	May 25, 2018
Priority date	May 25, 2018
Publication date	Jul 14, 2020
Grant date	Jul 14, 2020

Abstract

Switch assemblies and a switching method are disclosed. In some embodiments, a switch assembly may include a first contact element, and a second contact element operable with the first contact element. The first and second contact elements form an open circuit in a first configuration and form a closed circuit in a second configuration. At least one of the first contact element and the second contact element includes a magnetostrictive material. During operation, a magnetic field from a magnet causes the magnetostrictive material to deform or change shape/dimensions, thus causing the first and second contact elements to open or close. In some embodiments, the switch assembly is a micro-electro-mechanical-system (MEMS) switch.

First claim

What is claimed is:

1. A switch assembly comprising:
a first contact element operable with a second contact element to form an open circuit or a closed circuit, at least one of the first contact element and the second contact element including a magnetostrictive element coupled to a bi-metallic strip, the magnetostrictive element operable to bias the first contact element and the second contact element relative to one another to form the open circuit or the closed circuit, wherein the bi-metallic strip comprises a first strip formed of a first metal having a first coefficient of thermal expansion and a second strip coupled to the first strip and formed of a second metal having a second coefficient of thermal expansion different from the first coefficient of thermal expansion.

2. The switch assembly of claim 1 , further comprising a magnet proximate the first and second contact elements, wherein a magnetic field of the magnet causes the magnetostrictive element to change shape.

3. The switch assembly of claim 2 , wherein movement of the magnet relative to the first and second contact elements causes the first and second contact elements to change between the first configuration and the second configuration.

4. The switch assembly of claim 1 , wherein the magnetostrictive element is directly physically coupled to the first contact element or the second contact element.

5. The switch assembly of claim 1 , wherein at least one of the first contact element and the second contact element have a curved shape.

6. The switch assembly of claim 1 , wherein the first contact element curves away from the second contact element in a first configuration, and wherein the first contact element curves towards the second contact element in a second configuration.

7. The switch assembly of claim 1 , further comprising a switch circuit receiving an indication of the open circuit or the closed circuit.

8. A switching method comprising:
providing a first contact element operable with a second contact element, wherein the first and second contact member form an open circuit in a first configuration and form a closed circuit in a second configuration, and wherein at least one of the first contact element and the second contact element includes a magnetostrictive element coupled to a bi-metallic strip, wherein the bi-metallic strip comprises a first strip formed of a first metal having a first coefficient of thermal expansion and a second strip coupled to the first strip and formed of a second metal having a second coefficient of thermal expansion different from the first coefficient of thermal expansion; and
biasing the first contact element and the second contact element relative to one another using a magnetic field to change the shape the magnetostrictive element.

9. The switching method of claim 8 , further comprising changing the shape of the magnetostrictive element to form the open circuit and the closed circuit.

10. The switching method of claim 8 , further comprising providing a magnet proximate the first and second contact elements.

11. The switching method of claim 10 , further comprising causing the first and second contact elements to change between the first configuration and the second configuration in response to movement of the magnet relative to the first and second contact elements.

12. The switching method of claim 8 , further comprising directly physically coupling the magnetostrictive element to the first contact element or the second contact element.

13. The switching method of claim 8 , wherein at least one of the first contact element and the second contact element have a curved shape.

14. The switching method of claim 8 , wherein the first contact element curves away from the second contact element in the first configuration, and wherein the first contact element curves towards the second contact element in the second configuration.

15. The switching method of claim 8 , further comprising providing an indication of the open circuit or the closed circuit.

Assignees

• Littelfuse Inc

Inventors

• Johnson Brian

Classifications

• H01H36/00 Primary

  Switches actuated by change of magnetic field or of electric field, e.g. by change of relative position of magnet and switch, by shielding · CPC title

• H01H2036/0093

  Micromechanical switches actuated by a change of the magnetic field · CPC title

• H01H37/58

  actuated due to thermally controlled change of magnetic permeability · CPC title

• H01H55/00

  Magnetostrictive relays · CPC title