JPH0220167U

JPH0220167U -

Info

Publication number: JPH0220167U
Application number: JP9835388U
Authority: JP
Priority date: 1988-07-27
Filing date: 1988-07-27
Publication date: 1990-02-09

Description

[Brief explanation of drawings]

第１図乃至第５図は本考案の実施例を示すもの
で、第１図はブロツク図、第２図は第１図におけ
る自動移相補償回路の具体回路図、第３図は測定
周波数と相対位相角度のと関係を示すグラフ、第
４図は金属疲労度をパラメータとしてリフトオフ
を変化させた場合のベクトル特性を示すグラフ、
第５図はリフトオフをパラメータとして金属疲労
度に対する出力特性を示すグラフ、第６図乃至第
９図は従来例を示すもので、第６図はブロツク図
、第７図は検出ヘツドの構成を示す図、第８図は
金属疲労度をパラメータとしてリフトオフを変化
させた場合のベクトル特性を示すグラフ、第９図
はリフトオフをパラメータとして金属疲労度に対
する出力特性を示すグラフである。１３……自動利得制御機能付増幅器（利得制御
手段）、１４……第１の移相器、１５……検出ヘ
ツド、１５ｐ……１次コイル、１５ｓ……センサ
ーコイル（２次コイル）、１６……差動増幅器、
１７……第１の同期検波器、１９……第２の同期
検波器、２０……自動移相補償回路、２１……第
２の移相器。 Figures 1 to 5 show examples of the present invention. Figure 1 is a block diagram, Figure 2 is a specific circuit diagram of the automatic phase shift compensation circuit in Figure 1, and Figure 3 is a diagram showing the measurement frequency. A graph showing the relationship between the relative phase angle and Fig. 4 is a graph showing the vector characteristics when the lift-off is changed using the degree of metal fatigue as a parameter.
Fig. 5 is a graph showing the output characteristics with respect to the degree of metal fatigue using lift-off as a parameter, Figs. 6 to 9 show conventional examples, Fig. 6 is a block diagram, and Fig. 7 shows the configuration of the detection head. 8 is a graph showing the vector characteristics when the lift-off is changed using the degree of metal fatigue as a parameter, and FIG. 9 is a graph showing the output characteristics with respect to the degree of metal fatigue using the lift-off as a parameter. 13...Amplifier with automatic gain control function (gain control means), 14...First phase shifter, 15...Detection head, 15p...Primary coil, 15s...Sensor coil (secondary coil), 16 ...differential amplifier,
17...First synchronous detector, 19... Second synchronous detector, 20... Automatic phase shift compensation circuit, 21... Second phase shifter.

Claims

[Scope of utility model registration request]

A detection head having a primary coil and a secondary coil is provided, the primary coil of the detection head allows magnetic flux to pass through the material to be measured, the passing magnetic flux is detected by the secondary coil of the detection head, and the secondary coil A first phase shifter that outputs an AC voltage output having a phase difference from the AC voltage supplied to the primary coil in the metal fatigue degree measuring device that measures the metal fatigue degree of a material to be measured based on the detection output from the primary coil. a first synchronous detector that receives the detection output from the secondary coil of the detection head, rectifies it in synchronization with the output of the first phase shifter, and outputs the rectified signal to the outside as a metal fatigue degree; and a compensation command. an automatic phase shift compensation circuit that gives a command to change the amount of phase shift of the first phase shifter so that there is no change in the output of the first synchronous detector while the first synchronous detector is input; a second phase shifter that outputs an alternating current having a phase difference of π/2 with respect to the output of the phase shifter; and a second phase shifter that takes in the detection output from the secondary coil of the detection head; a second synchronous detector that rectifies in synchronization with the output; and gain control means that controls the amplitude of the AC voltage supplied to the primary coil of the detection head in response to the output of the second synchronous detector. A metal fatigue degree measuring device comprising: