JPH0637301Y2 - Vibration meter - Google Patents

Description

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

In the conventional vibrometer, the tip of the detection needle is pressed against the object to be detected,
The mechanical vibration transmitted through the detection needle is converted into an electric signal by an ultrasonic microphone arranged at the other end of the detection needle, and the electric signal is amplified and displayed. In this vibrometer, when the detection needle is tilted or the pressing force of the detection needle against the object to be detected is different, the detected vibration level is different, so the detection needle is guided in the axial direction and a constant force is applied. It is necessary to press it.

Conventional Technology Therefore, conventionally, the technology disclosed in Japanese Utility Model Laid-Open No. 63-111625 has been used. This is because the detection needle is attached to the casing of the probe so as to be slidable in the axial direction, the detection needle is urged by a spring to press the detection needle against the object to be detected, and the tip of the detection needle is projected. By pushing in and compressing the spring by a certain amount,
The detection needle is pressed against the object to be detected with a constant force.

The detection needle is generally made of a metal material such as stainless steel so that vibration can be easily transmitted, and the casing is also made of a metal material. In addition, an annular member made of resin or rubber is placed between the inner circumference of the casing and the outer circumference of the detection needle to guide the detection needle in the axial direction, reduce the sliding resistance of the detection needle, and reduce noise from the casing. Is cut off.

Problems to be Solved by the Invention In the above, when the object to be detected such as a steam trap is at a high temperature, the heat of the object to be detected is transferred to the annular member through the detection needle, and the annular member thermally expands. There is a problem that the dynamic resistance increases and the pressing force to the object to be detected increases.

Therefore, the technical problem of the present invention is to prevent the pressing force from changing even when the heat of the object to be detected is received.

MEANS FOR SOLVING THE PROBLEM The technical means of the present invention taken to solve the above-mentioned problems is to urge the detection needle with a spring to press the detection needle against the object to be detected so that the tip protrudes from the casing. By pushing the tip of the detection needle, the spring is compressed by a certain amount, and the microphone that converts the mechanical vibration of the detected object transmitted through the detection needle into an electric signal is installed in the casing on the other end side of the detection needle. In the one arranged inside,
A gap is provided between the inner circumference of the casing and the outer circumference of the detection needle, and a thin plate-shaped tire flam whose outer circumference is fixed to the casing and whose inner circumference is fixed to the detection needle is arranged at two positions on the front end side and the rear end side of the detection needle. The detection needle is connected to the casing.

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

Although there is a gap between the inner circumference of the casing and the outer circumference of the detection needle, the detection needle is guided by two diaphragms arranged at the front end side and the rear end side. When the tip of the detection needle is pressed against the object to be detected, the diaphragm bends and the detection needle compresses the spring by a certain amount and displaces in the axial direction. As described above, since there is no sliding portion between the detecting needle and the casing, sliding resistance does not occur. Therefore, the detection needle is always pressed against the object to be detected with a constant force.

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

As described above, according to the present invention, the object can be pressed against the object to be detected with a constant force regardless of the temperature of the object to be detected, so that the vibration level can be accurately detected.

EXAMPLE An example showing a concrete example of the present invention will be described (FIGS. 1 and 2).
See figure).

The casing of the vibrometer comprises a main body 1, a front case 2, a front cap 3 and a rear cap 4. The micro switch substrate 5, the stopper 6, the detection needle holder 7, the micro holder 8 and the substrate holder 9 are arranged in the casing. The micro switch substrate 5, the stopper 6, the detection needle holder 7, and the microphone holder 8 are connected by screws 10.

Place a sensing needle made of stainless steel in the casing. The detection needle is formed by screwing three members 11a, 11b, 11c, respectively. The inner peripheral surface of the diaphragm 12 formed of resin in a thin plate shape is sandwiched between the detection needles 11a and 11b. The outer peripheral side of the diaphragm 12 is sandwiched between the front case 2 and the float cap 3. Similarly, the inner peripheral side of the diaphragm 13 formed of resin in a thin plate shape is sandwiched between the detection needles 11b and 11c, and the outer peripheral side thereof is sandwiched between the detection needle holder 7 and the microphone holder 8. The detection needles 11a, 11b, 11c are urged by a spring 15 arranged between the detection needles 11a, 11b, and 11c, and their tips project beyond the tips of the front cap 3. By pushing the tip of the detection needle 11a to the tip of the front cap 3, the micro switch 16 attached to the micro switch substrate 5 is inserted. The micro switch 16 is switched on if the distance from the detection needle 11b is not more than a certain value, and is turned off if the distance is less than a certain value. A diaphragm 17 is attached to the rear end of the detection needle 11c with a set screw 18.

The ultrasonic microphone 20 is attached to the microphone holder 8 via the rubber cover 19. A sensor substrate 21 having a circuit for amplifying a detection signal is attached to the substrate holder 9. Reference numerals 22 and 23 are O-rings, and 24 and 25 are synthetic rubbers. Illustrations of electric wiring and parts of the board are omitted.

When the detection needles 11a, 11b, 11c are pressed against the object to be detected, the diaphragms 12, 13 are bent, the spring 15 is compressed, and the detection needles 11a, 11b, 11c are pushed to the front end of the front cap 3.
At this position, the micro switch 16 is turned on and the detection start state is set.

[Brief description of drawings]

1 is a sectional view of an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the upper end portion of FIG. 1: Main body 2: Front case 3: Front cap 7: Detection needle holder 8: Microphone holder 11: Detection needle 12: Diaphragm 13: Diaphragm 15: Spring 20: Ultrasonic microphone

Claims (1)

[Scope of utility model registration request] 1. A spring urges the detection needle to press the detection needle against the object to be detected so that the tip protrudes from the casing.
By pushing the tip of this detection needle, the spring is compressed by a certain amount, and the microphone that converts the mechanical vibration of the detected object transmitted through the detection needle into an electrical signal is installed in the casing on the other end side of the detection needle. The thin plate-shaped diaphragm having a gap between the inner circumference of the casing and the outer circumference of the detection needle, the outer circumference of which is fixed to the casing and the inner circumference of which is fixed to the detection needle. A vibrometer that is placed at a location and connects the detection needle and the casing.