JPH07900Y2 - Vibration meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a vibrometer used for detecting the vibration associated with the operation of a valve such as a steam trap or the vibration of a rotary shaft to confirm the quality of the operation.

2. Description of the Related Art A conventional vibrometer will be described with reference to Japanese Utility Model Publication 1-222107.

One end of the detection needle is applied to the object to be detected. The other end of the detection needle is fitted into a hole of a supporting member made of an elastic material, and an ultrasonic microphone using a piezoelectric element is fitted into a socket portion formed on the supporting member. The ultrasonic microphone is pressed against the other end of the detection needle by an annular protrusion formed at the end of the detection needle. When the tip of the detection needle is pressed against the object to be detected, mechanical vibration of the object to be detected acts on the piezoelectric element of the ultrasonic microphone through the detection needle. In response to this, a voltage change occurs in the piezoelectric element. This voltage fluctuation is amplified by an amplifier and the needle of the meter is shaken or the speaker is made to ring.

Problems to be Solved by the Invention In the above, there is a problem that the mechanical vibration of the object to be detected cannot be detected with high sensitivity. That is, since both the detection needle and the ultrasonic microphone are attached to the support member and these members are integrally displaced in the axial direction of the probe, the mechanical vibration in the axial direction of the detected object transmitted through the detection needle is superposed as pressure fluctuation. This is because the sound wave microphone is difficult to sense.

Therefore, the technical problem of the present invention is to enable the ultrasonic microphone to detect the mechanical vibration of the detected object transmitted through the detection needle with high sensitivity.

MEANS FOR SOLVING THE PROBLEM The technical means of the present invention taken to solve the above-mentioned technical problem is that a detection needle whose one end is brought into contact with an object to be detected is accommodated in a casing of a probe so as to be slidable in an axial direction. Then, the ultrasonic microphone using the piezoelectric element is fixed to the support member, the piezoelectric element is opposed to the other end of the detection needle, and is accommodated in the casing slidably in the axial direction. A spring, one end of which abuts on the support member and the other end of which abuts on the support member, is arranged between the fixed wall and the support member, and the piezoelectric element of the ultrasonic microphone is pressed against the other end of the detection needle to bring it into contact therewith. It is a thing.

Action The action of the above technical means is as follows.

The ultrasonic microphone is fixed to the support member and is pressed against the other end of the detection needle by a spring arranged between the fixed wall of the casing and the support member. Is transmitted to the ultrasonic microphone as pressure fluctuation while compressing the spring against the elastic force of the spring. Therefore, the ultrasonic microphone can detect vibration with high sensitivity.

Effect of the Invention The present invention has the following unique effects.

As described above, according to the present invention, since it is possible to obtain a vibrometer having a high sensitivity, it is possible to capture even a slight vibration of the object to be detected.

EXAMPLE An example showing a specific example of the present invention will be described (see FIG. 1).

The casing is formed of a front end member 2 and a rear end member 3 attached to both ends of a cylinder 1. The tip member 2 is made of a heat insulating material and is formed in a cylindrical shape with a small diameter in the upper part, and a detection needle 4 made of zirconia ceramic is accommodated in the small diameter portion and an ultrasonic microphone 5 is accommodated in the large diameter portion. The detection needle 4 is guided so as to be displaceable in the axial direction at a portion of the reference numeral 6 provided in the middle of the small diameter portion of the tip member 2.

A cross-shaped notch is provided at the upper end of the tip member 2. A chromel / alumel thermocouple 7 for temperature measurement is arranged outside the tip member 2. The thermocouple 7 is formed by bending an elongated thin plate and is located on the upper side of the projection between the notches of the tip member 2, and the side surface extending downward from both sides of the top surface and located on the side surface of the tip member 2. It consists of departments. A hole is made in the center of the upper surface, and the tip of the detection needle 4 is projected from there. The lower end of the side surface portion is connected to the following printed circuit board 8 mounted inside the cylinder 1. A contraction tube 9 is fitted around the tip member 2 and the thermocouple 7.

The ultrasonic microphone 5 has a cylindrical base 1 in the center of the end plate 10.
1. Plate-shaped piezoelectric elements 12 are bonded and fixed to each other, and both surfaces of the piezoelectric element 12 are connected to terminals 13 and 14 by conducting wires.
The end plate 10 and the terminals 13 and 14 are fitted into a support member 15 made of fluororesin. The outer diameter of the support member 15 is made slightly smaller than the inner diameter of the tip member 2 so that it can move freely in the axial direction.

A cylindrical portion is integrally provided on the upper portion of the cylinder 1 to form the fixed wall 16,
A spring 17 for urging the support member 15 upward is arranged between the fixed wall 16 and the support member 15. The upper surface of the piezoelectric element 12 of the ultrasonic microphone 5 is pressed against and comes into contact with the lower end surface of the detection needle 4 by the spring 17. An elongated hole 18 is formed in the center of the fixed wall 16.
Then, the lead wires from the terminals 13 and 14 of the ultrasonic microphone 5 are connected to the printed circuit board 8 through the hole 18.

The printed circuit board 8 is attached to a holder 19 held by the rear end member 3. The lead wire from the printed circuit board 8 is connected to the connector 20. Reference numerals 21 and 22 are screws for fixing the tip member 2 and the contraction tube 9 to the outer periphery of the fixed wall 16 of the cylinder 1.

The vibrometer operates as follows. The portion of the probe cylinder 1 is grasped by hand, the tip of the detection needle 4 is pressed against the object to be detected, and the tip is pushed to the position of the thermocouple 7. The mechanical vibration of the object to be detected passes through the detection needle 4 and the piezoelectric element 12 produces pressure fluctuations.
Act on. In response to this, a voltage change occurs in the piezoelectric element 12. The electrical signal and the temperature signal from the thermocouple 7 are sent to the printed circuit board 8 for processing, and a display (not shown) displays the judgment of pass / fail.

[Brief description of drawings]

FIG. 1 is a sectional view of a vibrometer probe according to an embodiment of the present invention. 1: Cylinder 2: Tip member 4: Detection needle 5: Ultrasonic microphone 7: Thermocouple 8: Printed circuit board 12: Piezoelectric element 15: Support member 16: Fixed wall 17: Spring

Claims (1)

[Scope of utility model registration request] 1. A detection needle, one end of which is applied to an object to be detected, is slidably accommodated in a casing of a probe in an axial direction, and an ultrasonic microphone using a piezoelectric element is fixed to a support member to detect the piezoelectric element. The other end of the fixed wall is slidably housed in the casing in the axial direction, and one end contacts a fixed wall formed in the casing and the other end contacts a support member to bias the support member. And a supporting member, and the piezoelectric element of the ultrasonic microphone is pressed against the other end of the detection needle to bring it into contact with the vibrometer.