JPS62148854A - Ae telemeter device - Google Patents

Abstract

PURPOSE:To transmit AE generated at a knife edge to the AE sensor of a transmitter without any attenuation and to detect the AE signal with a high level and a high SN ratio by fixing the transmitter on a main shaft of rotation. CONSTITUTION:The transmitter 10 is fixed to the upper part of the main shaft 2 of rotation and the coil part 20a of a receiver 20 is fitted. If a drill 3 is broken, AE is generated and propagated in the main shaft 2 of rotation to reach the transmitter 10. An AE sensor 11 inputs the oscillation signal to a band-pass amplifier 12 to amplify only the AE signal of a specific frequency component and an envelope detecting circuit 13 detects its envelope signal. The envelope signal is FM-modulated by a modulating circuit 14, received by a tuning amplifier circuit 22, and demodulated by a demodulating circuit 23, thereby stopping the rotation of the main shaft 2 of rotation and replacing the drill 3 automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an AE telemeter device used to detect metal damage or destruction, such as a broken blade of a machine tool.

(b) Conventional technology In general, the detection of drill breakage using NC machines, etc. is performed using AE (acoustic) of 200 to 300 KIIz when a drill breakage occurs.
Since a signal is generated, this AE multiplied signal is detected. Conventionally, a detector was provided at the edge of the table on which the workpiece was placed, and this detector detected the AE multiplied signal generated when the drill broke.

(c) Problems to be solved by the invention Since the AE detector of conventional machine tools is installed on the table, it is difficult to use a moving table type in which the workpiece is sent sequentially to the bottom of the drill spindle together with the table. In the conventional method, the AB detector had to be reinstalled every time the workpiece was changed, which was very troublesome.

Therefore, in order to solve this problem, a transmitter including an AE sensor was attached to the drill part, and the AE detected by the AE sensor was
An AE telemeter device is being considered in which the signal is transmitted from a multiplier signal transmitter and received by a receiver isolated from the transmitter. However, when the transmitter is attached to the spindle head, hair rings are included in the AE transport route from the drill to the spindle head, and the AE multiplied signal generated by the drill breakage is greatly attenuated at the point where it reaches the AE sensor. high SN
Cannot be detected by ratio.

Furthermore, since the transmitter has a built-in battery for driving the circuit, if the transmitter is attached to a high-speed rotating object, the components inside the battery will separate due to centrifugal force, and not only will power supply voltage not be able to be supplied to the circuit. It becomes a dangerous situation.

In view of the above, an object of the present invention is to provide an AE telemeter device in which a transmitter including an AE sensor is attached to the drill side, a high S/N ratio can be ensured, and battery failures do not occur.

(d) Means for solving the problem The AE telemeter device of this invention uses an AE sensor (II).
, an amplifier (12) that amplifies the AE multiplied signal of a predetermined frequency component from this AE sensor, a detection circuit (13) that produces an envelope signal of the AE multiplied signal of the frequency component, and modulates and modulates with the output of this detection circuit. A C/D that converts the AC voltage from the output circuit (14, 15, 16) including the transmitting coil that sends out waves and the power receiving coil (17) into DC voltage and supplies the power voltage to other circuits. C converter (18)
a transmitter (10) comprising a transmitter (10), a receiver coil (21) electromagnetically coupled to the transmitter coil, and a tuned amplifier circuit (21) that receives a modulated wave from the transmitter through the receiver coil.
2), an oscillation source (24, 26), and a power supply coil (25) driven by a signal from the oscillation source and electromagnetically coupled to the power receiving field of the transmitter (
20), the transmitter is fixedly installed on the rotating main shaft (2), while each coil of the receiver is loosely fitted on the rotating main shaft (2).

(E) Function In this AE telemeter device, an AC signal is supplied from the oscillation source of the receiver to the AC/DC converter of the transmitter via the coupling coil, and the AC/DC converter converts the AC signal. Converts to DC voltage and supplies power supply voltage to each circuit of the transmitter. When a drill breakage occurs and AE occurs, the AE multiplied signal is transmitted through the high-speed rotating main shaft, which is the drill main shaft.
The AE sensor detects this. Then, the desired frequency component is amplified by AE times by the bandpass amplifier, detected by the envelope detection circuit, the output circuit is modulated by this detection signal, and the modulated signal is sent to the tuned amplifier circuit of the receiver via the coupling coil. communicated. In the receiver, a demodulation circuit demodulates the received signal to an AE multiplied signal.

(f) Examples The present invention will now be explained in more detail with reference to Examples.

FIG. 1 is a circuit block diagram of an AE telemeter device showing one embodiment of the present invention.

This AE telemeter device is composed of a transmitter 10 and a receiver 20.

The transmitter 10 includes an AE sensor 11 formed of, for example, a piezoelectric element, a bandpass amplifier 12 that amplifies a signal of a predetermined frequency component by AE from the output of the AE sensor 11, an envelope detection circuit 13, and an FM converter for converting the detected envelope signal.
AC input from the modulation circuit 14 that modulates, the driver 16 that drives the transmitting coil 15, and the power receiving coil 17
It includes an A C/DC converter 18 that converts the voltage into a DC voltage.

The receiver 20 includes a tuned amplification circuit 22 that amplifies the signal inputted through the reception coil 21, a demodulation circuit 23 that outputs four envelope signals from the FM modulation signal, an oscillator 24, and a power supply coil 25 that is driven by the oscillation signal. driver 2
It is equipped with 6.

Note that the transmitting coil 15 and the receiving coil 21, and the power supply coil 25 and the power receiving coil 17 are electromagnetically coupled.

The transmitter 10 and receiver 20 of this AE telemeter device are mounted on a machine tool 1, as shown in FIG. In FIG. 2, a tool (drill blade) 3 is attached to the tip of a rotating spindle 2 of a machine tool 1, and a bearing 6 is interposed between the rotating spindle 2 and a spindle head 5. As shown in FIG. The rotating main shaft 2 is driven to rotate at high speed by a drive source not shown. A transmitter 10 is fixedly installed on the upper part of the rotating main shaft 2, and a receiver 2
0 coil portion 20a is inserted.

The mounting part of the transmitter 10 is shown in FIG.
The outer shape of 0 is formed into a torus shape. Further, the receiver 20 is configured to be separated into a coil portion 20a and a main body portion 20b, and the coil portion 20a is flat and has a ring-shaped tip, and a receiving coil 21 and a power supply coil 25 are wound within this ring-shaped portion. has been done.

Next, the operation of detecting drill breakage using this AE telemeter device will be described.

First, an oscillation signal is input from the oscillator 24 of the receiver 20 to the driver 2G, and this signal causes the power supply coil 25 to
is driven, passes through the power receiving coil 17, and is transmitted to the transmitter 10.
An AC voltage is input to the AC/DC converter 18 of the AC/DC converter 18, and this AC voltage is converted to a DC voltage, regulated to a constant voltage, and then sent to the bandpass amplifier 12, envelope detection circuit 13, .
. . . supplies power supply voltage to each circuit such as the driver 16. As a result, the transmitter 10 becomes activated.

Now, if the drill 3 breaks, AE will occur. This AE propagates through the rotating main shaft 2 and reaches the transmitter 10. The AE sensor 11 vibrates due to this AE, and inputs the vibration signal to the bandpass amplifier 12. Bandpass amplifier 12
amplifies only the AE multiplied signal of a predetermined frequency component, and outputs the envelope signal from the envelope detection circuit 13. Then, this envelope signal is transmitted to the modulation circuit 14
The signal is M-modulated and input to the driver 16. driver 16
drives the transmitting coil 15 with this FM modulated signal. Receiving coil 21 electromagnetically coupled to this transmitting coil 15
The FM modulated signal is received and amplified by the tuned amplifier circuit 22 through the tunable amplifier circuit 22. Next, this FM modulated signal is demodulated into an envelope signal, that is, by the AE multiplied signal demodulation circuit 23, and output. Based on this output signal, processing such as stopping the rotation of the rotary main shaft 2 and automatically replacing the drill 3 will be performed.

(G) Effects of the Invention According to this invention, since the transmitter is fixed to the rotating main shaft, the AE generated at the cutting edge is transmitted to the AE sensor of the transmitter without being attenuated. It can be detected at a high level and high SN ratio. In addition, since the transmitter's power supply voltage is supplied from the receiver's oscillation source, there is no built-in battery in the transmitter, eliminating the need for battery replacement, reducing maintenance opportunities, and eliminating the need to worry about batteries becoming defective. Therefore, the device of the present invention in which the transmitter is fixed to the high-speed rotating shaft can be used for AE detection with peace of mind.

Furthermore, when a workpiece is placed on a table and the table is sequentially moved to perform machining processing, there is no need to reset the AE detection device each time, so there is an advantage that the machining work can be performed easily.

[Brief explanation of drawings]

Fig. 1 is a circuit block diagram of an AE telemeter device showing an embodiment of the present invention, Fig. 2 is a sectional view showing the AE telemeter device installed in a machine tool, and Fig. 3 is the same installation state. FIG. 3 is an enlarged perspective view showing the vicinity of the transmitter. 2: Rotating main shaft, 10: Transmitter, 11: AE sensor, 12: Band pass amplifier, 13: Envelope detection circuit, 14: Modulation circuit, 15: Transmission coil, 16: Driver, 17: Power receiving coil, 18: A.C.
/DC converter, 20: receiver, 21: receiving coil, 22: tuned amplifier circuit, 23: demodulation circuit, 24: oscillator, 25
: Power supply coil, 26: Driver. Patent applicant Tateishi Electric Co., Ltd. Agent
Patent Attorney Shigeru Nakamura Figure 2 Figure 3

Claims (1)

[Claims] (1) An AE sensor, an amplifier that amplifies the AE signal of a predetermined frequency component from the AE sensor, a detection circuit that performs envelope detection of the AE signal of the frequency component, and a modulated wave that is modulated by the output of the detection circuit. An output circuit that includes a transmitting coil that sends out a
a transmitter including a DC converter; a receiver coil electromagnetically coupled to the transmitter coil; a tuned amplifier circuit that receives a modulated wave from the transmitter through the receiver coil; and derives an AE signal from the modulated wave. A receiver includes a demodulation circuit, an oscillation source, and a power supply coil driven by a signal from the oscillation source and electromagnetically coupled to a power reception coil of the transmitter, and the transmitter is connected to a rotating main shaft. The AE is characterized in that each coil of the receiver is loosely fitted to the rotating main shaft.
telemeter device