JPH10115566A - Shock-wave detecting sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor which is attached easily and by which the shock wave of a fluid inside a pipe can be detected at low costs and with high sensitivity. SOLUTION: A shock-wave detecting sensor is composed of a diaphragm 2 which receives the pressure of a fluid inside a pipe, of a microphone 3 which is faced with the diaphragm 2, of a shock-absorbing material 4 which is installed between the microphone 3 and the diaphragm 2, of an urging means 5 which urges the microphone 3 to the diaphragm 2 and of an isolation means 6 which isolates the microphone 3 acoustically from the circumference by excluding a part coming into contact with the diaphragm 2 via the shock-absorbing material 4. When the diaphragm 2 receives the shock wave of the fluid, the diaphragm 2 comes into contact with the microphone 3 via the shock-absorbing material 4, and a sound which is generated due to the contact of the microphone 3 is converted into an electric signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock wave detection sensor, in particular, a detection of a water hammer in a water supply circuit of a hydraulic circuit, a ride comfort sensor of a vehicle, a suspension control mechanism, an airbag system, and an SF-6 underground transmission line. The present invention relates to a shock wave detection sensor for detecting a shock wave of a fluid in a pipe, which is used in a short-circuit detection device for detecting a refrigerant fluid into a compressor of a refrigerating device, and the like.

[0002]

2. Description of the Related Art Conventionally, various shock wave detection sensors for detecting a shock wave of a fluid in a pipe have been used.
For example, an acceleration-type shock wave sensor is used in which a detection unit is brought into direct contact with the surface of a pipe to detect a shock wave by detecting vibration of the pipe as a change in acceleration.

Further, a pressure-type shock wave detection sensor that detects a shock wave by capturing a shock wave of a fluid in a pipe as a change in pressure and converting the shock wave into an electric signal of the pressure is also used.

Further, Japanese Patent Application Laid-Open No. 5-66228 discloses a vehicle side collision detecting device. As shown in FIG.
1 and the inner panel 102 are provided with a partition 107 to partition the inside of the door into two sealed areas.
An acoustic microphone 106 is provided in an area separated by the outer panel 101 and the outer microphone 7. And the door is obstacle 1
When the vehicle hits 10, the pressure fluctuation in the sealed area is detected by the acoustic microphone 106.

[0005]

However, in the case of the acceleration type shock wave sensor shown as the above-mentioned conventional example, it is difficult to catch a delicate shock wave of the fluid in the pipe as a change in acceleration. Since the detection capability of the sensor greatly changes depending on the manner in which the sensor is brought into contact with the pipe, there is a problem that it takes time for the mounting operation.

In the case of a pressure-type shock wave detection sensor, a high-sensitivity sensor can be obtained, but there is a problem that the whole apparatus is relatively expensive.

[0007] A type in which a pressure fluctuation in a closed area is detected by an acoustic microphone, such as a vehicle side collision detection device disclosed in Japanese Patent Application Laid-Open No. 5-66228, is used to detect a water hammer in a water supply circuit of a hydraulic circuit. When used for such purposes, there is a problem that it is difficult to detect only the shock wave with high sensitivity because it is easily affected by pressure fluctuations other than the shock wave.

In view of the above, the present invention has been made in view of the above-mentioned problems of the conventional shock wave detection sensor, and can easily detect the shock wave of the fluid in the pipe with easy installation of the sensor at low cost. An object is to provide a shock wave detection sensor.

[0009]

According to the first aspect of the present invention,
A shock wave detection sensor, a diaphragm that receives the pressure of the fluid in the pipe, a microphone provided opposite to the diaphragm, a cushioning member provided between the microphone and the diaphragm, and biases the microphone toward the diaphragm Biasing means, except for a portion that comes into contact with the diaphragm via the cushioning material, comprises insulating means for acoustically insulating the microphone from the surroundings, and when the diaphragm receives a shock wave of the fluid, A diaphragm contacts the microphone via the cushioning material,
The microphone converts sound generated by the contact into an electric signal.

According to the first aspect of the present invention, it is not necessary to bring the detecting section of the sensor into direct contact with the pipe, and the shock wave of the fluid in the pipe can be detected with high sensitivity with a simple configuration.

[0011]

Next, a specific example of an embodiment of a shock wave detection sensor according to the present invention will be described with reference to the drawings. As shown in FIG. 1, a shock wave detection sensor 1 according to the present invention includes a diaphragm 2, a microphone 3, an insulating cloth 4, a spring 5, an O-ring 6, and the like.

The diaphragm 2 is disposed in a space 31 communicating with the fluid passage 30 in the pipe, and functions as a vibration receiving plate for receiving a shock wave of the fluid in the pipe. The diaphragm 2 is made of metal, and is formed in a shape such that a shallow dish is inverted. The circumferential end of the diaphragm 2 is sandwiched by a cap 8 located below and a stopper 9 located above. Also, the diaphragm 2 and the stopper 9
A spacer 10 is mounted between them.

The microphone 3 is a microphone of a condenser type, a magnetic type, or the like. The tip 3a of the microphone 3 is in contact with the center 2a of the diaphragm 2 via an insulating cloth 4 made of felt. This insulating cloth 4 functions as a cushioning material, and the tip 3a of the microphone 3 and the center 2a of the diaphragm 2
The microphone 3 captures a sound generated when the tip 3a and the center 2a come into direct contact with each other due to minute fluctuations in the fluid pressure in the pipe.
To prevent the sensitivity from being affected.

The microphone 3 has a microphone holder 12.
, One end is urged downward by a spring 5 fixed to a spring retainer 13, and the distal end portion 3 a is constantly pressed against the central portion 2 a of the diaphragm 2 via the insulating cloth 4.

Further, between the side surface 3c of the microphone 3 and the guide fitting 15, two O-rings 6 as insulating means for acoustically insulating the microphone 3 from the surroundings are mounted, and a central portion of the diaphragm 2 is provided. The entry of sound from portions other than 2a is prevented.

A guide fitting 1 is provided around the diaphragm 2.
5 and a housing 16 integrally formed with an adhesive is located.
The housing 16 is integrated with the cap 8 and the stopper 9 by a caulking plate 18. Also, the guide fitting 15
A spring retainer 13 is fixed to the upper part of the head by a screw 17.

The upper part of the joint 11 is inserted and fixed in the center hole of the cap 8, and communicates the space 31 with the fluid passage 30. A fluid passage 30 formed in the center of the joint 11
Then, the space 31 is filled with a fluid for detecting a shock wave. The lead wire 3 b of the microphone 3 passes through a hole formed in the center of the microphone holder 12 and a hole formed in the center of the spring holder 13, and passes through the shock wave detection sensor 1.
Is derived outside.

In the shock wave detection sensor 1 having the above configuration, when the fluid in the pipe is in a stable state and when the pressure fluctuation is minute, the insulating cloth 4 is present, so that the center 2a of the diaphragm 2 and the tip of the microphone 3 are present. Since the portion 3a does not come into contact, the microphone 3 merely generates an electric signal corresponding to a minute sound. When the diaphragm 2 receives the shock wave of the fluid in the pipe, the central portion 2 of the diaphragm 2
a contacts the tip 3a of the microphone 3 via the insulating cloth 4, a relatively large sound generated by the contact is converted into an electric signal, and the shock wave detection circuit described below simply indicates that a shock wave has been detected. One pulse signal is obtained.

Next, the shock wave detecting circuit 20 provided in the shock wave detecting sensor 1 will be described. As shown in FIG. 2, the shock wave detection circuit 20 includes a band-pass filter amplifier 21 that amplifies only a signal component in a predetermined band of an output signal of the microphone 3 of the shock wave detection sensor 1 and a predetermined output signal of the band-pass filter amplifier 21. And a one-shot multivibrator 23 that outputs a single pulse signal when the output signal of the bandpass filter amplifier 21 is equal to or higher than the above level.

The output signal of the shock wave detection sensor 1 shown in FIG. 3A is amplified by the band-pass filter amplifier 21 while removing signal components other than the signal component generated by other than the shock wave of the fluid. The signal as shown in FIG. On the other hand, the comparator 22 outputs a pulse signal having a constant level A and a constant length B as shown in FIG. 3 (c), and outputs the pulse signal of the band-pass filter amplifier 21 of FIG. The pulse signals of c) are compared. Then, when the output signal of the band-pass filter amplifier 21 of FIG. 3B becomes equal to or higher than the level A of the pulse signal of FIG. 3C (point X in FIG. 3B), that is, sound having a predetermined value or more is detected. In this case, the one-shot multivibrator 23 outputs a single pulse signal of a predetermined length C as a shock wave detection signal as shown in FIG.

[0021]

According to the first aspect of the present invention, it is possible to provide a shock wave detection sensor which can easily install the sensor, is inexpensive and has high sensitivity, and can detect the shock wave of the fluid in the pipe.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a shock wave detection sensor according to the present invention.

FIG. 2 is a diagram showing a shock wave detection circuit attached to the shock wave detection sensor of FIG.

3 is a diagram showing each output signal in the shock wave detection circuit of FIG.

FIG. 4 is a sectional view showing a conventional shock wave detection sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shock wave detection sensor 2 Diaphragm 3 Microphone 4 Insulating cloth 5 Spring 6 O-ring 8 Cap 9 Stopper 10 Spacer 11 Joint 12 Microphone holder 13 Spring holder 15 Guide fitting 16 Housing 17 Screw 18 Caulking board 20 Shock wave detection circuit 21 Band filter amplifier 22 Comparator 23 One-shot multivibrator 30 Fluid passage 31 Space

Claims (1)

[Claims] 1. A diaphragm for receiving a pressure of a fluid in a pipe, a microphone provided opposite to the diaphragm, a cushioning member provided between the microphone and the diaphragm, and attaching the microphone to the diaphragm. Urging means, and excluding a portion that comes into contact with the diaphragm via the cushioning material, comprising insulating means for acoustically insulating the microphone from the surroundings, when the diaphragm receives a shock wave of the fluid,
A shock wave detection sensor, wherein the diaphragm contacts the microphone via the cushioning material, and the microphone converts sound generated by the contact into an electric signal.