JP2009097910A - Wire rope flaw detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wire rope flaw detection device having a small friction load when the wire rope is moving, little wear of a magnetic pole, and detection sensitivity hardly influenced by moving speed of the wire rope, and dispensing with an AC power source. <P>SOLUTION: This device is equipped with a U-shaped back yoke having two leg parts and a shell part having a split part, excitation magnetic poles provided on each end of the two leg parts, a pair of detection magnetic cores installed between the two leg parts, a pair of detection magnetic poles formed by winding detection coils on the pair of detection magnetic cores, a roller provided in a gap between the pair of detection magnetic cores, a magnetic rotor provided on the split part and equipped with a permanent magnet on the outer peripheral surface, and a rotation transfer mechanism for transferring rotation of the roller to the magnetic rotor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wire rope flaw detector that detects breakage of a long wire rope and a broken wire, and more particularly to a wire rope flaw detector that detects damage to a wire rope by leakage magnetic flux.

A wire rope flaw detector that detects damage of a wire rope by leakage magnetic flux passes the magnetic flux through the wire rope to be inspected by a magnetizer using a permanent magnet or an electromagnet. If the wire rope through which the magnetic flux passes is damaged, a leakage magnetic flux is generated from that portion. Therefore, an induced electromotive force generated by the leakage magnetic flux is detected and detected by an induction coil as a detection unit.
For example, a magnetizer composed of a pair of permanent magnets fixed to both ends of a strip-shaped yoke, a base that is coupled to the pair of permanent magnets of the magnetizer, and a pole piece provided at the tip of the base and the pole piece are bridged and fixed. There has been disclosed a wire rope damage detector composed of a U-shaped guide and a probe comprising an induction coil provided on the inner surface side of the U-shaped guide (see, for example, Patent Document 1).
In addition, there are three legs projecting almost in parallel at intervals, the E-shaped iron core whose both side legs function as excitation magnetic poles and the central leg functions as detection magnetic poles, and the core of the iron core A wire rope flaw detector provided with an excitation coil wound and connected to an AC power source and a detection coil wound around a central leg is disclosed (for example, see Patent Document 2).

Japanese Patent Laid-Open No. 9-210968 (page 3, FIG. 1) JP-A-10-19852 (pages 2 and 3, FIG. 1)

In the wire rope damage detector described in Patent Document 1, a wire rope is fitted into a U-shaped guide portion, and a DC magnetic field is applied to the probe by applying a DC magnetic field by a pair of permanent magnets of a magnetizer. To detect the damaged part.
For this reason, the strongly induced and excited wire rope is attracted to the U-shaped guide and rubs against the U-shaped guide, so that there is a problem in that the U-shaped guide is worn violently and the friction load of the wire rope is increased. .
The induced electromotive force generated in the induction coil for detecting the damaged part is proportional to the speed at which the damaged part of the wire rope passes through the induction coil, that is, the moving speed of the wire rope. Therefore, it is detected when the moving speed of the wire rope is low. There was a problem that the sensitivity would decrease.

The wire rope flaw detector described in Patent Document 2 applies an alternating current to the exciting coil wound around the body of the E-shaped iron core and applies an alternating magnetic field to the wire rope from both side legs that function as exciting magnetic poles. ing.
Since this wire rope flaw detector applies an alternating magnetic field to the wire rope, the attractive force due to the induction excitation of the wire rope becomes very small, and the wear of the magnetic pole part and the friction load of the wire rope are reduced. Further, by increasing the frequency of the alternating magnetic field, high detection sensitivity can be obtained even if the moving speed of the wire rope is low.
However, since this wire rope flaw detector applies an AC magnetic field to the wire rope by connecting an AC power source to the exciting coil, it requires an installation space for the external power source and costs due to the use of the external power source. There was a problem with the increase.

  The present invention has been made in order to solve the above-described problems. The object of the present invention is to reduce the friction load during traveling of the wire rope, to reduce the wear of the guide portion, the excitation magnetic pole, the detection magnetic pole, etc., and to detect the sensitivity. It is an object of the present invention to provide a wire rope flaw detector that is hardly affected by the moving speed of the wire rope and does not require an AC power source.

  A wire rope flaw detector according to the present invention includes a U-shaped back yoke provided with two leg portions protruding in parallel at both ends and a body portion provided with a split portion, and two legs of the back yoke. A pair of detections installed opposite each other with a gap between the excitation magnetic pole provided at the end of the part and provided with a slit in the wire rope to be inspected and the two legs of the back yoke An inspection provided in a gap between a pair of detection magnetic cores and a pair of detection magnetic cores formed by winding a detection coil around a pair of detection magnetic cores and sandwiching a wire rope to be inspected with a slit. A roller that is in contact with the target wire rope, a magnet rotor that is provided at a split portion in the body portion of the back yoke and that has a permanent magnet on the outer peripheral surface, and the rotation of the roller is transmitted to the magnet rotor to rotate the magnet rotor. With rotation transmission mechanism It is.

  A wire rope flaw detector according to the present invention includes a U-shaped back yoke provided with two leg portions protruding in parallel at both ends and a body portion provided with a split portion, and two legs of the back yoke. A pair of detections installed opposite each other with a gap between the excitation magnetic pole provided at the end of the part and provided with a slit in the wire rope to be inspected and the two legs of the back yoke An inspection provided in a gap between a pair of detection magnetic cores and a pair of detection magnetic cores formed by winding a detection coil around a pair of detection magnetic cores and sandwiching a wire rope to be inspected with a slit. A roller that is in contact with the target wire rope, a magnet rotor that is provided at a split portion in the body portion of the back yoke and that has a permanent magnet on the outer peripheral surface, and the rotation of the roller is transmitted to the magnet rotor to rotate the magnet rotor. With rotation transmission mechanism The friction load of the wire rope is small, there is no wear load of the excitation magnetic pole and the detection magnetic pole, high detection sensitivity is maintained regardless of the wire rope traveling speed, and no AC power source is required to generate an AC magnetic field The effect that there is.

Embodiment 1.
FIG. 1 is a schematic front view (a) and a schematic side view (b) showing a wire rope flaw detector according to Embodiment 1 of the present invention.
2 is a cross-sectional view taken along line AA in the wire rope flaw detector shown in FIG. 1A, and FIG. 3 is a cross-sectional view taken along line BB in the wire rope flaw detector shown in FIG.
4 is a CC cross-sectional view of the wire rope flaw detector shown in FIG. 1 (b), and FIG. 5 is a DD cross-sectional view of the wire rope flaw detector shown in FIG. 1 (b).
6 is an EE cross-sectional view of the wire rope flaw detector shown in FIG.
As shown in FIGS. 1 to 6, the wire rope flaw detector 100 of the present embodiment is made of a nonmagnetic metal such as aluminum or stainless steel or a plastics material, and protrudes substantially in parallel at intervals. In an E-shaped case 1 having legs, a back yoke 2 made of a ferromagnetic material such as iron, a permanent magnet 3 on the outer peripheral surface, a circular magnet rotor installed rotatably, and a wire rope A detection unit for detecting damage of 90, a roller 4 that rotates in contact with the wire rope 90 at the time of flaw detection, and a rotation transmission mechanism that transmits the rotation of the roller 4 to the rotation of the magnet rotor are housed.

As shown in FIG. 4 (case is not shown) and FIG. 5 (case is not shown), the back yoke 2 of the present embodiment has a U-shape having two legs protruding parallel to both ends. It is divided into three at its trunk. That is, the back yoke 2 includes an L-shaped first back yoke 21 composed of a leg portion and a body portion on one end side, and an L-shaped second back yoke composed of a leg portion and a body portion on the other end side. 22 and a third back yoke 23 at the center of the body.
As shown in FIG. 3, the end portion of the leg portion of the first back yoke 21 is U-shaped along the wire rope 90, and this portion applies the magnetic field to the wire rope 90. Acts as Although not shown, the end of the leg portion of the second back yoke 22 is also U-shaped along the wire rope 90 in the same manner as the end of the leg portion of the first back yoke 21. This portion also acts as the excitation magnetic pole 5 that applies a magnetic field to the wire rope 90.
In order to flow as much magnetic field as possible from the exciting magnetic pole 5 to the wire rope 90, it is desirable that the U-shaped exciting magnetic pole 5 has a structure overhanging the wire rope 90.
Further, the side surface portion of the case 1 corresponding to the shape of each exciting magnetic pole 5 of the first back yoke 21 and the second back yoke 22 is also U-shaped.

  In addition, a first magnet rotor 6 having a permanent magnet 3 on the outer peripheral surface is installed at a divided portion between the first back yoke 21 and the third back yoke 23, and the second back yoke 22 and the third back yoke 23 are connected to each other. The second magnet rotor 7 provided with the permanent magnet 3 on the outer peripheral surface is installed at a portion separated from the back yoke 23. The surface of the back yoke 2 facing the permanent magnet 3 is preferably about the arc length of one pole of the permanent magnet 3 provided on the outer peripheral surface of the magnet rotor (the magnetic pole length of the magnet). If the surface of the back yoke 2 facing the permanent magnet 3 is too larger than the magnetic pole length of the magnet, both the N pole and the S pole exist on the surface of the back yoke 2 facing the permanent magnet 3. The magnetic field applied to the wire rope 90 is weakened.

The permanent magnet 3 of the present embodiment is a rare earth-based permanent magnet, and, as shown in FIGS. 4 and 5, the shape is a donut shape, a circular first magnet rotor 6 and a circular second magnet. It is installed on the outer peripheral surface with the rotor 7. The permanent magnet 3 used in the present embodiment is a two-pole radial anisotropic ring magnet magnetized in the direction of the outer peripheral surface from the donut-shaped center, and the portion indicated by N in the figure is opposed to the back yoke 2. The surface to be formed forms the N pole, and the portion marked S forms the surface facing the back yoke 2 (the same applies to N and S marked on the permanent magnet in the following drawings). .
A cylindrical first magnet rotor gear 8 is provided on the side surface of the first magnet rotor 6, and a cylindrical second magnet rotor gear 9 is provided on the side surface of the second magnet rotor 7. It is fixed with an adhesive. The first magnet rotor 6 having the permanent magnet 3 on the outer peripheral surface is rotatably held in the case 1 by the first magnet rotor rotating shaft 10 together with the first magnet rotor gear 8. Further, the second magnet rotor 7 provided with the permanent magnet 3 on the outer peripheral surface is rotatably held in the case 1 by the second magnet rotor rotating shaft 11 together with the second magnet rotor gear 9.

Further, the split surface of the back yoke 2 needs to be close to the permanent magnet 3 in order to improve the excitation efficiency of the back yoke 2 by the permanent magnet 3 provided in each magnet rotor 6, 7. Therefore, the split surface of the back yoke 2, that is, the end portions of the body portions of the first back yoke 21 and the second back yoke 22 and the both end portions of the third back yoke 23, the permanent magnet 3 has two poles. Therefore, it is recessed as a concentric semicircle having a diameter slightly larger than the diameter of the outer peripheral surface of the donut-shaped permanent magnet 3.
The first and second magnet rotors 6 and 7 are made of a ferromagnetic material such as iron, and the first and second magnet rotor gears 8 and 9 are attached with iron-based dust or the like. Nonmagnetic materials are preferable for preventing the magnetic field that excites the wire rope 90, and nonmagnetic metals such as aluminum and stainless steel or plastics materials are used.

The detection part of this Embodiment is provided inside the center leg part of case 1, as shown in FIG.2, FIG.4 and FIG.6. The detection unit is wound around each of the pair of detection magnetic cores 12 and the pair of detection magnetic cores 12 along the respective inner walls on both sides of the central leg portion of the case 1 with a gap therebetween, and is connected in series. And a pair of detection coils 13.
A portion of the pair of detection magnetic cores 12 along which the detection coil 13 is wound and a slit is provided in the wire rope 90 is recessed so as to be U-shaped, and this portion serves as a detection magnetic pole 14. .
In the present embodiment, a nonmagnetic metal such as aluminum or stainless steel is used for the detection magnetic core 12, but in order to link more leakage magnetic flux to the detection coil 13, A ferromagnetic material such as iron may be disposed inside.
The detection coil 13 is connected to an amplifier (not shown).

As shown in FIGS. 2 and 4, the roller 4 according to the present embodiment is provided between a pair of detection magnetic cores 12, and a cylindrical roller gear 15 is disposed on the side surface of the roller 4. Yes. The roller 4 and the roller gear 15 are integrally formed or coupled by screws, an adhesive, or the like, and are rotatably held on the case 1 by a coaxial roller rotation shaft 16.
The roller 4 is disposed so as to be in contact with the wire rope 90, and is rotated by traveling in the longitudinal direction of the wire rope 90. And the surface which contacts the wire rope 90 of the roller 4 is a shape which follows the wire rope 90 in order to prevent that the wire rope 90 flutters during driving | running | working.

Further, in order to prevent the exciting magnetic pole 5 and the detecting magnetic pole 14 from being worn due to contact with the wire rope, when the wire rope 90 contacts the roller 4, the wire rope 90 and the U-shaped exciting magnetic pole 5 A predetermined slit is maintained between the wire rope 90 and the detection magnetic pole 14.
In the present embodiment, both the roller 4 and the roller gear 15 are made of, for example, non-magnetic metal such as aluminum or stainless steel or plastic in order to prevent adhesion of iron dust or the like and to prevent disturbance of the magnetic field that excites the wire rope 90. Material is used. If plastics material is used, the roller 4 and the roller gear 15 can be formed by integral molding.
In particular, urethane, rubber, or the like is provided on the outer periphery of the roller 4 in order to prevent the wire rope 90 from slipping during running and causing the roller 4 to rotate irregularly.

As shown in FIGS. 2 and 4, the rotation transmission mechanism of the present embodiment includes a roller gear 15, a first magnet rotor gear 8, a second magnet rotor gear 9, and a roller gear. 15 and the first magnet rotor gear 8 are respectively meshed with the cylindrical first rotation transmission gear 17, the roller gear 15, and the second magnet rotor gear 9. And the cylindrical second rotation transmission gear 18 installed in this manner.
The first rotation transmission gear 17 is held by a first rotation transmission gear rotary shaft 19, and the second rotation transmission gear 18 is held by a second rotation transmission gear rotary shaft 20 so as to be rotatable. The rotary shafts 19 and 20 for the second and second rotation transmission gears are attached to the case 1 in a cantilevered state.

The number of teeth of the roller gear 15 is larger than the number of teeth of the first and second rotation transmission gears 17 and 18, and the outer diameter of the roller gear 15 is the first and second rotation transmission gears. 17 and 18 are larger than the outer diameter. The first and second magnet rotor gears 8 and 9 and the first and second rotation transmission gears 17 and 18 have the same number of teeth and the same outer diameter.
With such a configuration, when the roller 4 rotates, the roller gear 15 rotates, the first magnet rotor gear 8 rotates through the first rotation transmission gear 17, and the second rotation transmission gear 18. Then, the second magnet rotor gear 9 is rotated.
That is, each of the first and second magnet rotors 6 and 7 provided with the permanent magnet 3 is rotated by the rotation of the roller 4.
In the present embodiment, the first and second rotation transmission gears 17 and 18 are also prevented from adhering to iron-based dust or the like, or from disturbance of the magnetic field exciting the wire rope 90, for example, aluminum or Nonmagnetic metals such as stainless steel and plastics materials are used.

  That is, in the wire rope flaw detector 100 of the present embodiment, when the wire rope 90 travels, the roller 4 rotates, and the permanent magnet 3 rotates by the rotation transmission mechanism including each gear. When the permanent magnet 3 rotates at the divided portion of the back yoke 2, the N pole and the S pole are alternately excited in the back yoke 2, and an AC magnetic field can be applied to the wire rope 90. At this time, in order to eliminate the disturbance of the magnetic field exciting the wire rope 90, the first rotation transmission gear 17 and the second rotation transmission gear 18 are in phase so that the rotations of the two permanent magnets 3 are synchronized. It has been assembled.

In the wire rope flaw detector 100 according to the present embodiment, an AC magnetic field is applied to the wire rope 90, so that the wire rope 90 is brought into contact with the exciting magnetic pole 5 and the detection magnetic pole 14 by the attractive force of induction excitation of the wire rope 90. Therefore, it is possible to prevent the excitation magnetic pole 5 and the detection magnetic pole 14 from being worn and reduce the friction load on the wire rope 90.
Further, in the wire rope flaw detector 100 of the present embodiment, an alternating magnetic field to be applied to the wire rope 90 is generated by the rotation of the permanent magnet 3 provided in the body portion of the back yoke 2 as the wire rope 90 travels. Therefore, an installation space is required, and an external power source that increases costs is unnecessary.

In the present embodiment, the number of teeth of the roller gear 15 is the number of teeth of the first and second rotation transmission gears 17 and 18 and the number of teeth of the first and second magnet rotor gears 8 and 9. Although it is more than the number, the number of teeth of all gears may be the same. In addition, the ratio between the number of teeth of the roller gear 15 and the number of teeth of the first and second rotation transmission gears 17 and 18 may be increased. The frequency can be increased.
In this embodiment, there is one rotation transmission gear for transmitting rotation from the roller gear to the magnet rotor gear, but there may be a plurality of rotation transmission gears.
That is, in the wire rope flaw detector 100 of the present embodiment, the traveling speed of the wire rope 90 is reduced by increasing the frequency of the alternating magnetic field applied to the wire rope 90 by setting the ratio of the number of teeth of each gear. High detection sensitivity can be obtained.

In the present embodiment, since the number of poles of the permanent magnet 3 is two, the back yoke 2 can be strongly excited, but the number of poles of the permanent magnet 3 may be four, six, eight, and ten poles. In this way, the frequency of the alternating magnetic field applied to the wire rope 90 can be increased, and high detection sensitivity can be obtained even when the traveling speed of the wire rope 90 is low. However, if the number of poles of the permanent magnet 3 exceeds 10, the excitation of the back yoke 2 becomes too weak and the detection sensitivity of the wire rope flaw detector decreases.
Moreover, although the radial anisotropic ring magnet is used for the permanent magnet 3, a polar anisotropic ring magnet or a linear anisotropic ring magnet may be used. When the anisotropic ring magnet is polar anisotropy, the magnetic flux density distribution on the surface is close to a sine wave and changes smoothly, so the pulsation during rotation is reduced and the change in magnetic flux flowing through the wire rope (noise) is reduced. Therefore, the S / N ratio of the detection signal can be increased. Further, although the rare earth permanent magnet is used for the permanent magnet 3, a ferrite or a bonded magnet may be used.
In the present embodiment, two magnet rotors including the permanent magnet 3 are provided, but more magnet rotors may be provided.
FIG. 7 shows a permanent magnet (a) combined with an arc-shaped magnet and a permanent magnet (b) having a petal-like outer diameter, which are other shapes of permanent magnets used in the wire rope flaw detector according to the present embodiment. It is a figure which shows a permanent magnet (c) with a petal-shaped inner diameter and a rod-shaped permanent magnet (d).
As shown in FIG. 7, in this embodiment, the permanent magnet is not limited to a ring magnet such as a donut shape, but is a permanent magnet 24 that combines arc-shaped magnets, a permanent magnet 25 with a petal-like outer diameter, and an inner diameter shape. May be either the petal-shaped permanent magnet 26 or the rod-shaped permanent magnet 27.

In this embodiment, when the number of poles of the permanent magnet 3 is increased, the magnetic pole length of the magnet is shortened, so that the arc length of the surface of the back yoke 2 facing the permanent magnet 3 is shortened.
Further, since the alternating magnetic field is excited by the rotation of the permanent magnet 3, an eddy current flows in the back yoke 2 in a direction to cancel the change of the flowing magnetic field, and the magnetic field flowing through the wire rope 90 is reduced. In order to prevent this, it is desirable to use a laminated body of electromagnetic steel plates or a powder iron core compression-molded by providing a resin film on iron powder for the back yoke 2.
In order to prevent iron-based dust and the like from adhering to the excitation magnetic pole portion of the back yoke 2, a nonmagnetic metal cover may be provided at least along the U-shaped portion of the excitation magnetic pole.

Next, one example of the wire rope flaw detector 100 according to the present embodiment will be described.
In this embodiment, for example, the surface of the U-shaped exciting magnetic pole 5 facing the wire rope 90 having an outer diameter of 12 mm has a diameter of an arc portion of 13 mm so as to follow the outer diameter shape of the wire rope 90. ing. An air gap of 0.5 mm is maintained between the wire rope 90, the excitation magnetic pole 5 and the pair of detection magnetic cores 12. A detection coil having a wire diameter of 0.05 mm is wound around each of the pair of detection magnetic cores 12. An air gap of 0.5 mm is also maintained between the permanent magnet 3 and the back yoke 2.
The outer diameter of the roller 4 is 25 mm, the outer diameter of the roller gear 15 is 24 mm, and the number of teeth is 36. The outer diameters of the first and second rotation transmission gears 17 and 18 are 7 mm, the number of teeth is 12, and the outer diameters of the first and second magnet rotor gears 8 and 9 are also 7 mm. The number of teeth is also twelve.
In this embodiment, for example, when the wire rope 90 travels at 50 m / min, the frequency of the alternating magnetic field excited by the wire rope is about 30 Hz.

Next, operation | movement of the wire rope flaw detector 100 of this Embodiment is demonstrated.
FIG. 8 is a diagram illustrating a state in which a damaged portion of the wire rope is detected by the wire rope flaw detector according to the present embodiment.
As shown in FIG. 8, a wire rope 90 to be inspected is arranged on a U-shaped excitation magnetic pole 5 and a detection magnetic pole 14 recessed in a U shape by a pair of detection magnetic cores 12, and is in contact with the roller 4. . The wire rope 90 is in contact only with the roller 4 and does not rub against the wire rope 90, the two excitation magnetic poles 5 and the detection magnetic pole 14, and the friction load of the wire rope 90 and the wear load of the flaw detection apparatus are not affected. Can be prevented.

When the roller 4 is rotated by the travel of the wire rope 90, the permanent magnet 3 is rotated through the respective gears, an alternating magnetic field flows through the back yoke 2, and the excitation magnetic pole 5 alternately becomes an N pole and an S pole. The direction of 28 also changes alternately in the opposite direction accordingly.
At this time, if the wire rope 90 is not damaged, there is no leakage magnetic flux from the traveling wire rope 90 and there is no magnetic flux interlinking the detection coil 13, so the detection voltage is zero. On the other hand, when the wire rope 90 is damaged and this damaged part passes through the detection magnetic pole 14, the leakage magnetic flux 29 generated in the damaged part passes through the detection magnetic pole 14, and a voltage is generated in the detection coil 13 to detect the damaged part. To do.

Next, it will be described that the wire rope flaw detector 100 according to the present embodiment has high detection sensitivity of a damaged portion even when the traveling speed of the wire rope 90 is low.
FIG. 9 is a diagram showing a waveform of a leakage magnetic flux generated from a damaged portion of the wire rope and interlinked with the detection coil in the wire rope flaw detector according to Embodiment 1 of the present invention. FIG. It is a figure which shows the induced voltage to generate | occur | produce.
In the wire rope flaw detector to which a DC magnetic field is applied, as the wire rope travels and the damaged portion approaches the detection coil, the leakage magnetic flux φ (t) passing through the detection coil gradually increases as shown by A in FIG. When the damaged part comes closest to the detection coil, the leakage magnetic flux peaks. The peak value of this leakage flux is assumed to be φ0.
At this time, the magnitude of the induced electromotive force generated in the coil is proportional to the amount of change dφ (t) / dt [Wb / s] of the magnetic flux interlinking the coil rings, so that the induced voltage is that of the wire rope. Depends on travel speed. Also, as shown by A in FIG. 10, for example, if the induced voltage when the damaged part approaches the detection coil is positive, the induced voltage when the damaged part moves away from the detection coil becomes negative. When the damaged part comes closest to the detection coil and the leakage magnetic flux reaches a peak (φ0), the induced voltage is zero.

In the wire rope flaw detector to which an AC magnetic field is applied, as the wire rope travels and the damaged portion approaches the detection coil, the leakage magnetic flux passing through the detection coil gradually increases as shown by B in FIG. As a result, the polarity of the leakage magnetic flux changes alternately.
At this time, the leakage magnetic flux can be expressed as (φ0 + φ (t)) sinωt. Here, ω = 2πf, and f is a frequency determined by the roller diameter, the gear ratio, and the number of poles of the permanent magnet.
Accordingly, the amount of change in leakage flux per unit time linked to the coil ring is dφ (t) / dt = (dφ (t) / dt) sinωt + (φ0 + φ (t)) ωcosωt. The first term is the amount of change in leakage magnetic flux generated when the wire rope travels, and the second term is the amount of change in leakage magnetic flux due to application of an alternating magnetic field.

Since the magnitude of the induced electromotive force generated in the detection coil is proportional to dφ (t) / dt [Wb / s], when an AC magnetic field is applied, the wire rope runs and is damaged as shown by B in FIG. In addition to the induced electromotive force generated in proportion to the speed at which the part passes the detection magnetic pole, the induced electromotive force is generated even if the leakage magnetic flux changes due to the AC magnetic field, and the wire rope travel speed is slow. A high detection voltage can be obtained. Even if the direction of the magnetic flux changes (that is, the polarity is reversed) when the damaged part passes through the detection coil, the voltage is detected only by changing the sign of the detection voltage.
For example, in the wire rope flaw detector 100 of the present embodiment, the detected voltage when the wire rope 90 is excited using an AC magnetic field with a frequency of 40 Hz is as strong as the amplitude of the AC magnetic field as shown in FIG. Compared to the case where the wire rope 90 is excited by a direct current magnetic field of about 3.5 times.

In the wire rope flaw detector 100 according to the present embodiment, the roller 4 is arranged so that the wire rope 90 always keeps a distance from the back yoke, and an AC magnetic field is applied to the wire rope 90. Therefore, it is possible to prevent the excitation magnetic pole 5 and the detection magnetic pole 14 from being worn and to reduce the friction load on the wire rope 90, and to obtain high detection sensitivity regardless of the traveling speed of the wire rope 90.
In addition, the AC magnetic field is generated by rotating the roller 4 by running the wire rope 90, and this rotation is performed by the rotation of the permanent magnet 3 transmitted through the gear, so that the AC power source for generating the AC magnetic field is generated. Is unnecessary.

Embodiment 2. FIG.
FIG. 11 is a schematic diagram showing a portion of the rotation transmission mechanism in the wire rope flaw detector according to Embodiment 2 of the present invention.
As shown in FIG. 11, in the rotation transmission mechanism 60 in the wire rope flaw detector according to the present embodiment, the roller gear is not provided on the side surface of the roller, and the roller gear 31 is disposed on the inner peripheral surface of the roller 30. Is provided. There is no roller rotation shaft that holds the roller 30 and the roller gear 31.
Further, in the rotation transmission mechanism 60 in the wire rope flaw detector according to the present embodiment, the rotation transmission gear is not used, and the roller gear 31, the first magnet rotor gear 32, and the second magnet rotor gear 33 are used. Is a structure that meshes directly.
A first magnet rotor 6 having a permanent magnet 3 on the outer peripheral surface is provided on the side surface of the first magnet rotor gear 32, and an outer peripheral surface is provided on the side surface of the second magnet rotor gear 33. A second magnet rotor 7 having a permanent magnet 3 is provided.

Then, the first magnet rotor rotating shaft 34 that supports the first magnet rotor 6 and the first magnet rotor gear 32 coaxially, the second magnet rotor 7 and the second magnet rotor gear 33 are provided. A second magnet rotor rotating shaft 35 supported coaxially is disposed on the diameter of the roller 30 parallel to the body (not shown) of the back yoke 2. That is, the roller 30 is held by the first magnet rotor gear 32 and the second magnet rotor gear 33 that directly mesh with the roller gear 32.
The wire rope flaw detector according to the present embodiment is the same as the wire rope flaw detector according to the first embodiment except that the rotation transmission mechanism 60 has the planetary gear structure as described above, and the wire rope flaw detector according to the first embodiment. As well as having the same effect as the above, since no rotation transmission gear is used, the number of parts is small and the cost can be reduced.

Embodiment 3 FIG.
FIG. 12 is a schematic diagram showing a wire rope flaw detector according to Embodiment 3 of the present invention.
As shown in FIG. 12 (the case is not shown), in the wire rope flaw detector 300 according to the present embodiment, the back yoke 36 is divided into two parts at the body part, and the outer peripheral surface is formed on the divided part. Is provided with a permanent magnet 3 and a magnet rotor 38 provided with a magnet rotor gear 37 on a side surface. The magnet rotor gear 37 is directly meshed with the roller gear 15.
That is, in the wire rope flaw detector 300 according to the present embodiment, the back yoke 36 is divided into two, and the divided portion is provided with the permanent magnet 3 on the outer peripheral surface and the magnet rotor gear 37 on the side surface. Except for the structure in which one magnet rotor 38 is arranged and the magnet rotor gear 37 is directly meshed with the roller gear 15, it is the same as the wire rope flaw detector of the first embodiment.
The wire rope flaw detector 300 according to the present embodiment has the same effects as the wire rope flaw detector according to the first embodiment, does not use a rotation transmission gear, and has only one magnet rotor 38. The number of parts is small and the cost can be reduced.

Embodiment 4 FIG.
FIG. 13 is a schematic diagram showing a portion of the rotation transmission mechanism in the wire rope flaw detector according to Embodiment 4 of the present invention.
As shown in FIG. 13, in the wire rope flaw detector of the present embodiment, the rotation transmission mechanism 70 is replaced with the roller gear 15 in the wire rope flaw detector 300 of the third embodiment, and the roller rotor is magnetized in multiple poles. A magnet rotor 38 having a permanent roller 39 having a permanent magnet 39 on its outer peripheral surface, a magnet rotor gear 37 joined to a side surface of the wire rope flaw detector 300, and having a permanent magnet 3 on its outer peripheral surface. Instead of using only the ferromagnetic magnet rotor 42 provided on the outer peripheral surface with the magnet rotor permanent magnet 41 that is multipolarly magnetized with the number of magnetic poles of the roller rotor permanent magnet 39 or less, the wire according to the third embodiment is used. The same as the rope flaw detector 300.

  In the wire rope flaw detector according to the present embodiment, when the wire rope 90 travels, the roller rotor 40 disposed coaxially with the roller 4 in contact with the wire rope 90 rotates. Thus, for example, when the N pole of the roller rotor permanent magnet 39 comes to a position facing the permanent magnet 41 for magnet rotor (referred to as a facing position), the S pole of the permanent magnet 41 for magnet rotor is attracted to this N pole. Next, when the south pole of the roller rotor permanent magnet 39 comes to the opposite position, the north pole of the magnet rotor permanent magnet 41 is attracted to the south pole. By repeating this, the magnet rotor permanent magnet 41 rotates, an alternating magnetic field flows through the back yoke 36, and the excitation magnetic pole 5 becomes N and S poles alternately.

In the present embodiment, the number of magnetic poles of the roller rotor permanent magnet 39 is larger than the number of magnetic poles of the magnet rotor permanent magnet 41, but may be the same. For the roller rotor permanent magnet 39 and the magnet rotor permanent magnet 41, either a radial anisotropic ring magnet, a polar anisotropic ring magnet, or a linear anisotropic ring magnet is used. When the permanent magnet is a polar anisotropic ring magnet, the magnetic flux density distribution on the surface is close to a sine wave and changes smoothly, so the pulsation during rotation is reduced and the change in magnetic flux (noise) flowing through the wire rope is small. Therefore, the S / N ratio of the detection signal can be increased.
Moreover, the permanent magnet used may be not only a ring magnet but also a combination of a plurality of magnets having a circular arc shape in part.
The rotation transmission mechanism 70 in the wire rope flaw detector according to the present embodiment transmits the rotation of the roller 4 in a non-contact manner without using a gear to rotate the permanent magnet. The wire rope flaw detector according to the present embodiment. The apparatus has the same effect as that of the wire rope flaw detector 300 according to the third embodiment, and includes a rotation transmission mechanism that has no wear and has a long life.

Embodiment 5 FIG.
FIG. 14 is a perspective view showing a ferromagnetic roller rotor in which a plurality of donut-shaped permanent magnets are provided on the outer peripheral surface in a wire rope flaw detector according to Embodiment 5 of the present invention.
FIG. 15 is a top view of a ferromagnetic roller rotor in which a plurality of donut-shaped permanent magnets are provided on the outer peripheral surface shown in FIG.
As shown in FIG. 14, in the wire rope flaw detector according to the present embodiment, the first roller rotor permanent magnet 44, the second roller rotor permanent magnet 45, and the third roller rotor are provided on the outer peripheral surface of the ferromagnetic roller rotor 43. The wire rope flaw detector is the same as that of the fourth embodiment except that the permanent magnet 46 is in contact with the permanent magnet 46 and arranged in this order in the axial direction of the roller rotor.

In the present embodiment, as shown in FIGS. 14 and 15, for example, a 4-pole first roller rotor permanent magnet 44, a 6-pole second roller rotor permanent magnet 45, and an 8-pole third roller rotor. A permanent magnet 46 is provided on the outer peripheral surface of the roller rotor 43.
The roller rotor 43 is held so as to be movable in the axial direction. By moving the roller rotor 43 in the axial direction, the pole of the permanent magnet for the roller rotor facing the permanent magnet for the magnet rotor provided on the outer peripheral surface of the magnet rotor. The number can be changed.
That is, the wire rope flaw detector of the present embodiment changes the combination of the roller rotor permanent magnet and the magnet rotor permanent magnet, and changes the rotation of the magnet rotor permanent magnet, thereby changing the frequency of the alternating magnetic field that excites the back yoke. A frequency variable mechanism for changing the frequency is provided.

In the wire rope flaw detector provided with the frequency variable mechanism according to the present embodiment, when the rope traveling speed is relatively fast, the roller rotor permanent magnet portion having a small number of poles is used, and when the rope traveling speed is slow, the pole By using a large number of roller rotor permanent magnets, the rotational speed of the permanent magnet for the magnet rotor is kept high, and the frequency of the alternating magnetic field that excites the back yoke is increased, thereby reducing the magnetic flux density leaking from the damaged portion of the rope. The proportional induced voltage can be increased and the detection sensitivity can be increased.
Also in this embodiment, the permanent magnet for the magnet rotor, the permanent magnet 44 for the first roller rotor, the permanent magnet 45 for the second roller rotor, and the permanent magnet 46 for the third roller rotor include a radial anisotropic ring magnet and a pole. Either an anisotropic ring magnet or a linear anisotropic ring magnet is used. And when a polar anisotropic ring magnet is used, the magnetic flux density distribution on the surface is close to a sine wave and changes smoothly, so the pulsation during rotation is reduced and the change (noise) in the magnetic flux flowing through the wire rope is reduced. Therefore, the S / N ratio of the detection signal can be increased.

FIG. 16 is a top view of a ferromagnetic roller rotor in which a plurality of skewed donut-shaped permanent magnets are provided on the outer peripheral surface.
A permanent magnet provided on the outer peripheral surface of the roller rotor is provided with a first skewed roller rotor permanent magnet 47 having 4 poles and a second skewed roller rotor permanent magnet 48 having 6 poles and a third skew having 8 poles. Since the roller rotor permanent magnet 49 is used, the pulsation during rotation is reduced, the change (noise) in the magnetic flux flowing through the wire rope is reduced, and the S / N ratio of the detection signal can be increased.
Although not shown in the drawing, the width of the second roller rotor permanent magnet 45 is made smaller than the width of the first roller rotor permanent magnet 44 in the axial direction, and the width of the second roller rotor permanent magnet 42 is further reduced. Further, the width of the third roller rotor permanent magnet 46 may be reduced.
In this case, for example, the distortion of the magnetic flux density distribution on the surface of the first roller rotor permanent magnet 44 can be reduced by the second and third roller rotor permanent magnets 45 and 46, and the pulsation during rotation is reduced. Therefore, the change (noise) of the magnetic flux flowing through the wire rope can be reduced, and the S / N ratio of the detection signal can be increased.
In the present embodiment, there are three types of donut-shaped permanent magnets with different numbers of poles provided on the outer peripheral portion of the roller rotor, but the present invention is not limited to this.
In this embodiment, a plurality of donut-shaped permanent magnets are provided on the outer peripheral surface of the roller rotor, but a plurality of donut-shaped permanent magnets may be provided on the outer peripheral surface of the magnet rotor.

  The wire rope flaw detector according to the present invention has no wear on each magnetic pole part, and the friction with the wire rope is small, and the damaged part of the wire rope can be detected with high sensitivity. Can be used for flaw detection.

It is the front schematic diagram (a) and the side schematic diagram (b) which show the wire rope flaw detector concerning Embodiment 1 of this invention. It is AA sectional drawing in the wire rope flaw detector shown to Fig.1 (a). It is BB sectional drawing in the wire rope flaw detector shown to Fig.1 (a). It is CC sectional drawing in the wire rope flaw detector shown in FIG.1 (b). It is DD sectional drawing in the wire rope flaw detector shown in FIG.1 (b). It is EE sectional drawing in the wire rope flaw detector shown in FIG. It is a figure which shows the permanent magnet of another shape used for the wire rope flaw detector concerning Embodiment 1 of this invention. It is a figure which shows the state which detects the damaged part of a wire rope with the wire rope flaw detector concerning Embodiment 1 of this invention. It is a figure which shows the waveform of the leakage magnetic flux which generate | occur | produces from the damaged part of a wire rope in the wire rope flaw detector concerning Embodiment 1 of this invention, and links a detection coil. It is a figure which shows the induced voltage which generate | occur | produces in the detection coil in the wire rope flaw detector concerning Embodiment 1 of this invention. It is a schematic diagram which shows the part of the rotation transmission mechanism in the wire rope flaw detector concerning Embodiment 2 of this invention. It is a schematic diagram which shows the wire rope flaw detector concerning Embodiment 3 of this invention. It is a schematic diagram which shows the part of the rotation transmission mechanism in the wire rope flaw detector concerning Embodiment 4 of this invention. It is a perspective view which shows the ferromagnetic roller rotor by which several donut-shaped permanent magnets were provided in the outer peripheral surface in the wire rope flaw detector concerning Embodiment 5 of this invention. FIG. 15 is a top view of a ferromagnetic roller rotor in which a plurality of donut-shaped permanent magnets are provided on the outer peripheral surface shown in FIG. 14. FIG. 3 is a top view of a ferromagnetic roller rotor in which a plurality of skewed donut-shaped permanent magnets are provided on the outer peripheral surface.

Explanation of symbols

1 Case, 2 Back yoke, 3 Permanent magnet, 4 Roller, 5 Excitation magnetic pole,
6 first magnet rotor, 7 second magnet rotor, 8 first magnet rotor gear,
9 Gear for second magnet rotor, 10 Rotating shaft for first magnet rotor,
11 Rotation shaft for second magnet rotor, 12 detection magnetic core, 13 detection coil,
14 detection magnetic pole, 15 roller gear, 16 roller rotation shaft,
17 1st rotation transmission gear, 18 2nd rotation transmission gear,
19 Rotation shaft for first rotation transmission gear, 20 Rotation shaft for second rotation transmission gear,
21 first back yoke, 22 second back yoke, 23 third back yoke,
24 Permanent magnets combined with arc-shaped magnets, 25 Permanent magnets with petal-shaped outer periphery,
26 Permanent magnet with inner petal shape, 27 Rod-shaped permanent magnet, 28 Exciting magnetic flux,
29 Leakage magnetic flux, 30 roller, 31 roller gear, 32 first magnet rotor gear,
33 Second magnet rotor gear, 34 First magnet rotor rotation shaft,
35 Second rotating shaft for magnet rotor, 36 Back yoke, 37 Magnet rotor gear,
38 magnet rotor, 39 roller rotor permanent magnet, 40 roller rotor,
41 permanent magnet for magnet rotor, 42 magnet rotor, 43 roller rotor,
44 permanent magnet for the first roller rotor, 45 permanent magnet for the second roller rotor,
46 3rd permanent magnet for roller rotors,
47 a first skewed roller rotor permanent magnet,
48 second skewed roller rotor permanent magnets,
49 Third skewed permanent magnet for roller rotor, 60, 70 rotation transmission mechanism,
90 Wire rope, 100, 300 Wire rope flaw detector.

Claims (7)

A U-shaped back yoke provided with two leg portions projecting in parallel at both ends and a body portion provided with a dividing portion; and provided at the end portions of the two leg portions of the back yoke. An excitation magnetic pole arranged with a slit in the wire rope to be inspected, a pair of detection magnetic cores placed opposite each other with a gap between the two legs of the back yoke, and the pair of detection magnetic cores A pair of detection magnetic poles formed by winding a detection coil around the pair of detection magnetic poles sandwiching the wire rope to be inspected with a slit, and the wire rope to be inspected provided in a gap between the pair of detection magnetic cores A roller that contacts, a magnet rotor that is provided in the divided portion of the body portion of the back yoke and has a permanent magnet on the outer peripheral surface; and the rotation of the roller is transmitted to the magnet rotor to rotate the magnet rotor. With rotation transmission mechanism Wire rope flaw detector, characterized in that. A rotation transmission mechanism, a roller gear disposed on a side surface of the roller, a magnet rotor gear disposed on a side surface of the magnet rotor, and a rotation transmission gear meshing with the roller gear and the magnet rotor gear; The wire rope flaw detector according to claim 1, wherein the wire rope flaw detector is formed by: The rotation transmission mechanism includes a roller gear provided on the inner surface of the roller, a permanent magnet on the outer peripheral surface, and is disposed on a side surface of the first magnet rotor provided in the first divided portion of the back yoke. A first magnet rotor gear meshing with the roller gear; a permanent magnet on the outer peripheral surface; and disposed on a side surface of the second magnet rotor provided in the second divided portion of the back yoke. The wire rope flaw detector according to claim 1, wherein the wire rope flaw detector has a planetary gear structure formed by a second magnet rotor gear meshing with the gear. The rotation transmission mechanism is formed by a roller gear disposed on a side surface of the roller and a magnet rotor gear disposed on a side surface of the magnet rotor and meshing with the roller gear. The wire rope flaw detector according to 1. A rotation transmission mechanism is provided on the outer surface of the roller rotor that is disposed on the side surface of the roller and includes a permanent magnet for a roller rotor that is magnetized in multiple poles, and a permanent magnet for a magnet rotor that is magnetized in multiple poles. 2. The wire rope flaw detector according to claim 1, wherein the permanent magnet for a rotor of a roller is formed with a narrow gap with respect to the permanent magnet for a roller rotor. 6. The wire rope flaw detector according to claim 5, wherein the roller rotor or the magnet rotor includes a plurality of donut-shaped permanent magnets having different numbers of poles on an outer peripheral portion. The wire according to any one of claims 1 to 6, wherein the permanent magnet is any one of a radial anisotropic ring magnet, a polar anisotropic ring magnet, and a linear anisotropic ring magnet. Rope flaw detector.

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