Title:
VIBRATION SENSOR
Document Type and Number:
Japanese Patent JP3304286
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a vibration sensor whose sensitivity is increased and by which a vibration waveform can be detected at low costs and with good accuracy by a method wherein a very small gap is formed between the piezoelectric ceramic face of a unimorph piezoelectric element and a case which is faced with it and the protrusion part of a weight is brought into contact with the face of a metal diaphragm.
SOLUTION: When the vibration of the rotating drum of an automatic washing machine is to be controlled with high accuracy, it is required to detect a very small vibration (at an acceleration of 0.1 or lower) at a low speed of rotation. For this, a piezoelectric ceramic 25 which is installed only on one face of a metal diaphragm 24 at a piezoelectric element is faced with a case base 26, and the metal diaphragm 24 is brought into contact with the protrusion part 23a of a weight 23. In addition, a very small gap, e.g. in the permissible bending amount portion of the piezoelectric element, is formed between the piezoelectric ceramic 25 and the base 26 so as to increase a detecting sensitivity. By this constitution, the surface of the piezoelectric ceramic 25 is not damaged by the protrusion part 23a of the weight 23, the piezoelectric element can be bent according to an applied acceleration, and the piezoelectric element is not damaged.
Inventors:
Yoshiya Hayashida
Application Number:
JP16855497A
Publication Date:
July 22, 2002
Filing Date:
June 25, 1997
Export Citation:
Assignee:
Sharp Corporation
International Classes:
G01P15/09; D06F33/02; G01H11/08; (IPC1-7): G01H11/08; D06F33/02; G01P15/09
Domestic Patent References:
| JP277640U | ||||
| JP5621728U | ||||
| JP62178377U |
Attorney, Agent or Firm:
Takaya Koike