Vibration detecting sensor

• US 5,834,650 A
• Filed: 10/10/1996
• Issued: 11/10/1998
• Est. Priority Date: 03/07/1996
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Tae-ho
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US08/731,171
• Time in Patent Office: 761 Days
• Field of Search: 73/514.34, 73/497, 73/651, 73/654, 73/35.11, 73/35.13, 310/329, 310/331
• US Class Current: 73/651
• CPC Class Codes: B06B 1/0603 using a piezoelectric bender, e.g. bimorph
• CPC Class Codes: G01H 11/08 using piezoelectric devices

Abstract

A vibration detecting sensor includes a pair of piezo-electric elements electrically connected together using a plate member, which eliminates the influences of temperature change to the surroundings by using a temperature compensating piezo-electric element, and prevents external noises from entering the device. Therefore, vibrations are detected efficiently.

Claims

1. A vibration detecting sensor comprising:

a vibrating case;

an isolating member attached to said vibrating case;

a cantilever-structured piezo-electric vibrator, one end of which is supported by said isolating member, the cantilever-structured piezo-electric vibrator comprising a pair of piezo-electric elements.

electrode layers on the upper and lower surfaces of said piezo-electric vibrator;

a plate member connecting said electrode layers to act as a short;

a covering member covering said vibrating case;

a lead-in wire connected to said piezo-electric vibrator through said covering member; and

an amplifier connected to said lead-in wire.

2. The vibration detecting sensor as claimed in claim 1, wherein said isolating member is composed of Al₂ O₃.

3. The vibration detecting sensor as claimed in claim 1, wherein said piezo-electric vibrator has a bimorphic structure in which a first piezo-electric element for detecting vibration and a second piezo-electric element for temperature compensation are stacked.

4. The vibration detecting sensor as claimed in claim 3, wherein said first and second piezo-electric elements are polarized in the same direction.

5. The vibration detecting sensor as claimed in claim 3, wherein a metallic plate acting as a junction electrode is inserted between said first and second piezo-electric elements.

6. A vibration detecting sensor as claimed in claim 5, wherein said metallic plate has a projecting portion projecting from one side of said piezo-electric vibrator and a ground wire is connected to said projecting portion.

7. The vibration detecting sensor as claimed in claim 1 wherein said plate member is composed of copper (Cu).

8. The vibration detecting sensor as claimed in claim 1, wherein said covering member has a hole through which said lead-in wire is inserted, and said hole is sealed with a glass material.