Micromachined mechanical switch

• US 7,745,746 B2
• Filed: 01/22/2008
• Issued: 06/29/2010
• Est. Priority Date: 01/22/2008
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies Sensonor AS (Infineon Technologies AG)
• Inventors: Lohndorf, Markus, Kvisteroey, Terje
• Primary Examiner(s): Luebke; Renee S
• Assistant Examiner(s): HOMZA, LISA NHUNG
• Application Number:
  US12/017,769
• Publication Number:
  US 20090183979A1
• Time in Patent Office: 889 Days
• Field of Search: 200/61.49, 200/61.46, 200/61.45 R, 200245-247
• US Class Current: 200/61.45R
• CPC Class Codes: B60C 23/0459 self triggered by motion sensor
• CPC Class Codes: B60C 23/0488 Movement sensor, e.g. for sensing angular speed, acceleration or centripetal force
• 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 35/14 Switches operated by change of acceleration, e.g. by shock or vibration, inertia switch wherein the liquid constitutes a contact of the switch H01H29/002

Abstract

A mechanical switch is arranged to electrically connect a power source to an electrical component. The switch includes a resilient structure, a first electrically conductive element connected to the power source and a second conductive element connected to the electrical component. At least one of the conductive elements is attached to the resilient structure. The switch is arranged such that the conductive elements are positioned out of contact with one another in the absence of a force being applied to the switch, and the resilient structure is moveable in response to a force applied thereto, the force being applied upon rotation of a tire to which the switch is connected. Upon the application of a force above a predetermined threshold, the resilient structure moves to bring the conductive elements into contact with one another, the contact electrically connecting the power source to the electrical component.

Claims

1. A tire pressure monitoring system (TPMS) comprising:

a power source;

TPMS circuitry; and

a mechanical switch positioned between the power source and the TPMS circuitry and arranged to electrically connect a power source to an electrical component, the switch comprising;

a resilient structure; and

a first electrically conductive element connected to the power source and a second conductive element connected to the electrical component, at least one of the conductive elements being attached to the resilient structure,

wherein the switch is arranged such that;

the conductive elements are positioned out of contact with one another in the absence of a force being applied to the switch;

the resilient structure is moveable in response to a force applied thereto, the force being applied upon rotation of a tire to which the switch is connected; and

upon application of a force above a predetermined threshold, the resilient structure moves to bring the conductive elements into contact with one another, the contact electrically connecting the power source to the electrical component.

2. The switch according to claim 1, wherein the electrical component forms part of the tire pressure monitoring system (TPMS).

3. The switch according to claim 1, wherein the force is applied in a substantially radial direction of the tire.

4. The switch according to claim 1, wherein the switch is a micro mechanical device.

5. The switch according to claim 1, wherein the resilient structure is arranged such that the resilient structure is sensitive to an acceleration in the order of between 1 g and 10 g, where g is the gravitational acceleration.

6. The switch according to claim 1, wherein contact resistance between the electrically conductive elements is less than 100 ohms.

7. The switch according to claim 1, wherein at least one of the electrically conductive elements comprise gold.

8. The switch according to claim 1, wherein at least one of the electrically conductive elements comprise ruthenium.

9. The TPMS according to claim 1, wherein the system is arranged to determine a footprint of a tire in which the TPMS is provided.

10. The TPMS according to claim 9, wherein the system is arranged to determine vertical load of a vehicle comprising the tire in which the TPMS is provided.