JPS61137083A - Apparatus for measuring coercive force of ferromagnetic test piece - Google Patents

Abstract

PURPOSE:To enable accurate measurements at a single stroke of a plurality of test pieces, by fixing in line in the radial direction on a test piece holder a plurality of ferromagnetic test pieces and arranging the same quantity of detecting coils as the text piece allowing the coils to face the passing locus of the test piece. CONSTITUTION:This apparatus is constructed with magnetizing coil 12 and demagnetizing coil 14 arranged tightly and coaxially inside the coil 12. Inside a hollow space of a cylindrical hollow solenoid 10, test piece holder 26 and detecting coil 28 are installed one against the other. The holder 26 is fixed to one of the ends of a rotating shaft 30 and the coil 28 is mounted to one of the ends of a hollow pipe 38 inside the solenoid 10. And, a plurality of ferro magnetic test pieces are admitted through a plurality of holding holes perforated at the specified distance in the radial direction on the open end surface of the holder 26, the coils 28 are arranged in the same number of the test pieces focing the passing locus of the test pieces. Further, the test pieces are magnet ized by the coils 12 and the holder 26 is rotated for measurement of the coercive force.

Description

[Detailed Description of the Invention] Industrial Application Field □ This invention relates to a device for measuring coercive force of ferromagnetic test pieces, and more specifically, it relates to a device for measuring coercive force of a plurality of ferromagnetic test pieces. This invention relates to a device that can perform simultaneous measurements.

Prior Art Iron and other metal materials that exhibit properties as ferromagnetic materials are tested for their magnetic properties as magnetic materials prior to factory shipment by extracting a sample of the metal material and measuring its magnetic properties. It is common practice to do so. As shown in Figure 1, when the magnetic field strength H is plotted on the horizontal axis and the magnetic flux density B is plotted on the vertical axis, the magnetic field strength is 0.
It is shown as a magnetization curve that changes as →a-+b→C and reaches magnetic saturation at the 0 point. Note that when the magnetic field is weakened from the magnetic saturation point C, the magnetization strength follows the path C-4d→e→f and becomes saturated at point f.0 Then, when the magnetic field is strengthened again, the magnetization becomes f-+g. → follows a path of 1+c and changes in a circular manner, drawing a so-called hysteresis loop curve. At this time, the magnitude of Od is referred to as residual magnetic flux density Br, and the magnitude of Os is referred to as coercive force Ha. Then, the magnetization characteristics such as magnetic flux density and coercive force (B-
Measurement of H) has conventionally been carried out by the ring-shaped core method using a ring-shaped sample, or by using a self-recording magnetometer or an NS permeability meter. Among these various methods for measuring magnetization characteristics, especially NS
Measuring the coercive force of a rod-shaped test piece using a magnetic permeability meter has the disadvantages of complicated work procedures, requiring time and effort, and requiring skill.

Therefore, a new means for solving the above-mentioned drawbacks was proposed by the applicant of the present invention, and a patent application was filed on June 27, 1981 as the invention ``Method and Apparatus for Measuring Coercive Force of Ferromagnetic Test Pieces.'' In this measurement method, a magnetic field from a magnetizing coil is applied to a ferromagnetic test piece placed in a solenoid to magnetize the test piece, and the magnetized test piece is placed in a detection coil also placed in the solenoid. An induced voltage is generated in the detection coil by relative rotation, and an external magnetic field necessary for canceling the induced voltage is applied to the magnetized test piece by a demagnetizing coil to reduce the induced voltage to zero. The content is that the strength of the external magnetic field is calculated as the coercive force. In addition, as a device for carrying out this measurement method, a solenoid is constructed by arranging a magnetizing coil and a demagnetizing coil concentrically, and a test piece holder for mounting a ferromagnetic test piece in the solenoid and an induced voltage detection device are provided. It has been proposed that a test piece holder and a detection coil for use in the test piece are arranged facing each other at a predetermined distance apart, and the test piece holder can be rotated relative to the detection coil.

Problems to be Solved by the Invention The measuring method and device according to this application are extremely useful in that they can satisfactorily solve the above-mentioned drawbacks and realize highly accurate coercive force measurement. Only one ferromagnetic test piece can be measured per measurement operation, and there is a problem in that it is inefficient and takes time to measure many test pieces.

Purpose of the Invention The present invention has been devised to solve the above-mentioned problems, and is capable of measuring a plurality of ferromagnetic test pieces in one measurement operation, thereby reducing the effort and time required to measure coercive force. The purpose is to improve work efficiency by omitting this.

Means for Solving the ProblemsThe inventors have made various studies to solve the above-mentioned problems, and have found that in order to measure the coercive force of multiple ferromagnetic test pieces in one operation, It has been found that a plurality of test pieces may be mounted on the holder in a state in which they are aligned in the radial direction, or a plurality of test pieces may be mounted on the holder at a required phase angle in the rotational direction. That is, in order to achieve the above object, the present invention provides the above-described coercive force measurement apparatus for ferromagnetic test pieces, in which a plurality of ferromagnetic test pieces are mounted in a radial alignment in a test piece holder, and each The detection coils are arranged in a number corresponding to the number of test pieces so as to face the locus of passage of the magnetic test pieces. Further, in another invention of the present application, in the coercive force measuring device for a ferromagnetic test piece as described above, a plurality of ferromagnetic test pieces are mounted on a test piece holder at a required phase angle in the rotation direction, and
The single detection coil is arranged opposite to the locus of passage of each ferromagnetic test piece.

Operation With this configuration, when a plurality of magnetized test pieces are rotated relative to the detection coil, the test pieces sequentially pass in front of the detection surface of the detection coil, An induced voltage corresponding to each test piece is generated in sequence. -Example Next, the coercive force measuring device according to the present invention will be described in detail by giving preferred examples and referring to the accompanying drawings. FIG. 2 shows a schematic configuration of a coercive force measuring device according to the present invention, and reference numeral 10 designates a solenoid consisting of a cylindrical air core with a predetermined diameter. The solenoid 10 includes a magnetizing coil 12 formed by winding a copper wire a predetermined number of times around a bobbin (not shown), and a demagnetizing coil 14 which is also wound around a bobbin (not shown) and closely concentrically arranged inside the magnetizing coil 12. It basically consists of. Further, a cylindrical metal magnetic shield plate 16 is disposed in close contact with the outer circumferential portion of the solenoid 10 .

The solenoid 10 is a housing (not shown) of the measuring device.
Power supply lines 18.20 led out from the magnetizing coil 12 and demagnetizing coil 14 constituting the solenoid are respectively connected to a dedicated DC power source 22.24. Also, in the cavity of the solenoid 10, a test piece holder 26 and a detection coil 28 are provided as shown in the figure.
are arranged to face each other at a predetermined distance apart (details of this configuration will be described later with reference to FIG. 3), and the test piece holder 26 extends horizontally outward in the axial direction of the solenoid 10. Fixed to one end of the rotating shaft 30, the rotating shaft 3
0 is rotatably supported by a pair of bearings 34 provided on a support base 32. The other end of the rotating shaft 30 is connected via a coupling to the rotating shaft of a DC motor 36 whose rotation speed can be adjusted steplessly.

The detection coil 28 is attached to one end of a metal hollow pipe 38 extending horizontally within the solenoid 10, and the hollow end of the hollow pipe 38 is connected to the housing outside the solenoid 10. It is fixed to the body (not shown) via appropriate means. Note that the detection coil 2
8, a lead wire 40 is led out along the hollow pipe 38 and connected to a suitable measuring circuit. For example, as shown in FIG. 2, this measurement circuit includes a detection amplifier 42. Capacitor 44. AC voltmeter 46 and X-Y recorder 48
The X-terminal of the X-Y recorder 48 is connected to a standard resistor 50 with a center tap connected to a power supply line 20 connecting the demagnetizing coil 14 and its DC power supply 24. .

Next, an enlarged view of the circular part indicated by the symbol A in Fig. 2 is shown.
Shown in FIGS. 3 and 5. That is, FIG. 3 shows the main configuration according to the invention of the present application in terms of the positional relationship between the test strip 52 and the detection coil 28 arranged in the test strip holder 26. As is clear from FIG. 4, the test piece holder 26 is constituted by a disc-shaped member made of, for example, a non-magnetic material, and is screwed and fixed to the end of the rotating shaft 30 at its center. The ferromagnetic test pieces 52 cut out from a metal material such as iron are respectively inserted into a plurality of storage holes drilled at predetermined intervals in the radial direction in the open end surface of the test piece holder 26, and are then inserted into a plurality of storage holes formed at predetermined intervals in the radial direction. It can be installed removably. By attaching it in this manner, a plurality of ferromagnetic test pieces 52 are arranged on the flat end surface of the test piece holder 26 at a predetermined distance apart in the radial direction. Furthermore, this test piece 52
is magnetized by an external magnetic field as described later, and is mounted in such a position that the direction of magnetic flux generation when magnetized is parallel to the central axis of the rotating shaft 30 that pivotally supports the test piece holder 26.

In this case, the detection coil 28 is supported by a pipe 38 and located in front of the test piece holder 26, and the rotation shaft 3
0 axis, and as shown in FIG. In the example, 2
Individual). As shown in FIG. 7, each of the detection coils 28 is constructed by winding a copper wire a required number of times around two acrylic bobbins 54a and 54b, for example. Note that the copper wires of the two bobbins are connected to the magnetizing coil 1 as described later.
In order to cancel the applied magnetic field generated when the bobbins 2 are excited, the bobbins 54a and 54b are wound in opposite directions, respectively. Furthermore, the most appropriate distance between the detection head of the detection coil 28 and the ferromagnetic test piece 2 is determined experimentally, but it is generally preferable to set it to 1.0 mm to 2.0 mm. .

Furthermore, FIGS. 5 and 6 show the main part configuration of a coercive force measuring device according to another invention of the present application.

In particular, as shown in No. 6 @, ferromagnetic test pieces are inserted into a plurality of storage holes sequentially drilled at a required phase angle in the rotational direction on the open end surface of the test piece holder 26, which is made up of one disc-shaped member. 52 are respectively inserted and removably attached by appropriate fixing means. By mounting in this manner, a plurality of ferromagnetic test pieces 52 are positioned on the flat end surface of the test piece holder 26 at a required phase angle in the rotation direction.

In this case, the detection coil 28 is connected to each ferromagnetic test piece 5.
The structure is such that only one is disposed opposite the two passing loci.

In the embodiment shown in FIGS. 2 to 6, the test piece holder 2
6 is driven and rotated by the motor 36, and the detection coil 2
8 has a structure in which it remains stationary at a fixed position, but it may be constructed so that the detection coil 28 is rotated and the test piece holder 26 is kept stationary. Therefore, the rotational relationship between the test piece holder 26 and the detection coil 28 is relative to each other.

Next, the actual use of the coercive force measuring device according to the present invention constructed as described above will be explained. Prior to the start of the measurement, a rod-shaped test piece 52 of predetermined dimensions (for example, diameter 5 mm, maximum length 30 mm) is obtained from a metal material made of iron or other ferromagnetic material,
This test piece 52 is attached to the holder 26 having the above-described configuration. That is, in the apparatus according to the invention shown in FIG. 3, a plurality of ferromagnetic test pieces 52 are attached to the test piece holder 26 in an array at a predetermined distance apart in the radial direction, and in the apparatus according to the invention shown in FIG. In this apparatus, a plurality of ferromagnetic test pieces 52 are mounted on a test piece holder 26 at a required phase angle in the rotational direction.
is installed so that it is located. During this installation work, the test piece holder 26 is moved back in the axial direction together with the support base 32 by a slide mechanism (not shown), and with the holder 26 positioned outside the solenoid IO, the test piece 52 is installed. It's starting to look like nothing. Next, the test piece holder 26 is inserted forward into the solenoid IO, and the position is set so that a predetermined gap is obtained between the detection coil 28 and the test piece 52.

After the setting of the test piece 52 is completed in this way, the magnetization coil 12 is excited by the DC power supply 22, and the solenoid 1
A magnetic field is applied to the internal space of 0. The DC power supply used is, for example, 15A, and the maximum applied magnetic field is 8600.
It is e. By placing a plurality of test pieces 52 made of ferromagnetic material in this applied magnetic field, the test pieces 52 are magnetized and reach magnetic saturation at the zero point as shown in the graph of FIG. After reaching this magnetic saturation point C, when the magnetic field formed by the magnetizing coil 12 is weakened, the strength of magnetization gradually decreases, and after reaching the residual magnetization point d with zero magnetic field, it is saturated at the f point. . At this point, the excitation by the magnetizing coil 12 is stopped.

Next, the motor 36 shown in FIG. 2 is energized to rotate the rotating shaft 30 and the test piece holder 26 attached to its tip (the number of rotations is selected, for example, in the range of 100 to 700 rpm). At this time, in the device according to the invention shown in FIG.
The plurality of test pieces 52 magnetized by the magnetization coil 12
is a plurality of detection coils 2 corresponding to each of the test pieces 52.
8. It passes on the circular trajectory located in front with the required period. In the apparatus according to another invention shown in FIG. 5, a plurality of test pieces 52 magnetized by the magnetization coil 12 sequentially pass on a circular trajectory located in front of the single detection coil 28. Therefore, in either case, the magnetic flux 60 generated from the test piece 52 is transferred to the detection coil 2 as shown in FIG.
8 detection surfaces periodically. As a result, the magnetic flux passing through the detection coil 28 generates an induced voltage e in the detection coil 28 according to the principle of electromagnetic induction.

Further, substantially in synchronization with the start of rotation of the test piece holder 26, the demagnetizing coil 14 is excited by the DC power supply 24 (for example, current LA), and a new external magnetic field is applied to the solenoid 10. The magnetic field applied by the demagnetizing coil 14 is set to be in the opposite direction to the magnetic field applied by the magnetizing coil 12. Further, the strength thereof is, for example, the maximum applied magnetic field 200e, which is set to be sufficient to cancel the magnetization of the test piece 52 induced in the detection coil 28. As a result, the residual magnetization in the test piece 52 decreases, and the induced voltage e also decreases accordingly. The relationship between the current flowing through the magneto-magnetic coil 14 and the induced voltage is expressed as X
-Y, L/ is instructed by the coder 48, the magnetic field is determined by an appropriate arithmetic circuit from the value at which the induced voltage e becomes zero, and the strength of this external magnetic field is taken as the coercive force.

Effects of the Invention As described above, according to the coercive force measuring device according to the present invention, a plurality of ferromagnetic test pieces are attached to the test piece holder in a radial alignment or at a required phase angle in the rotational direction. By being configured to attach them one after another, the coercive force of a plurality of ferromagnetic test pieces can be accurately measured in one operation, which has the advantage of dramatically improving measurement efficiency.

[Brief explanation of drawings]

Fig. 1 is a magnetization curve diagram showing the relationship between magnetic field strength H and magnetic flux density B in a magnetic material, Fig. 2 is a schematic configuration diagram of the coercive force measuring device for a test piece according to the present application, and Fig. 3 is a diagram showing the relationship between magnetic field strength H and magnetic flux density B in a magnetic material. 2 is an enlarged vertical sectional view of the circular portion indicated by the symbol A in FIG. 2, FIG. 4 is an explanatory perspective view showing the outline of the configuration shown in FIG. 3, and FIG. 6 is an explanatory perspective view showing the outline of the structure shown in FIG. 5, FIG. 7 is a perspective view of an embodiment of the detection coil, and FIG. 8 is a diagram showing the detection of a test piece. It is an explanatory view showing a change in magnetic flux when rotated relative to a coil. F! 0.1 FIG, 7 FIG, 8

Claims (2)

[Claims] (1) A magnetizing coil and a demagnetizing coil are wound concentrically to form a solenoid, and a test piece holder that holds a ferromagnetic test piece in this solenoid is separated from a detection coil for detecting induced voltage. In the coercive force measurement apparatus for ferromagnetic test pieces, the test piece holder is configured to be arranged facing each other and rotated relative to the detection coil. A ferromagnetic device characterized in that the detection coils are arranged in a radial direction and installed, and the number of detection coils corresponding to the number of ferromagnetic test pieces is arranged opposite to the locus of passage of each ferromagnetic test piece. Coercive force measuring device for body test pieces. (2) A magnetizing coil and a demagnetizing coil are wound concentrically to form a solenoid, and the test piece holder that holds the ferromagnetic test piece in the solenoid is separated from the detection coil for detecting the induced voltage. In the coercive force measurement apparatus for ferromagnetic test pieces, the test piece holder is configured to be arranged facing each other and rotated relative to the detection coil. A storage device for a ferromagnetic test piece, characterized in that the detection coil is mounted at a required phase angle in the rotational direction, and the single detection coil is arranged opposite to the locus of passage of each ferromagnetic test piece. Magnetic force measurement device.