JP2010014659A - Flaw detector of wire rope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flaw detector of a wire rope that has high versatility and high detection accuracy of a leaking magnetic flux. <P>SOLUTION: This flaw detector of the wire rope includes a magnetic flux detecting means 2 for magnetizing the wire rope 4 in the longitudinal direction and detecting the leaking magnetic flux, and a demagnetizing mean 3 for removing the remaining magnetism of the wire rope 4. The demagnetizing mean 3 icludes a plurality of magnetizers 5 arranged with a predetermined interval along the longitudinal direction of the wire rope 4. Each magnetizer 5 is constituted by a first permanent magnet 6 and second permanent magnet 7 so that the direction of the magnetic flux is orthogonal to the longitudinal direction of the wire rope 4. The first permanent magnet 6 and second permanent magnet 7 are arranged so that the directions of the magnetic fluxes generated from adjacent magnetizers 5 are different from each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wire rope flaw detector using an electromagnetic flaw detection method.

  Wire ropes are often used in elevators, lifts, cable cars, cranes, etc., but local damage due to fatigue, wear, etc. occurs depending on the frequency of use, and the wire ropes of the components are broken sequentially. The number of breaks increases over time, and when the number of breaks exceeds a predetermined value, it is determined that the wire rope has reached the end of its life and is replaced. Therefore, it is necessary to measure whether the wire rope can be used safely by measuring the number of breaks of the wire rope by periodic inspection.

  An electromagnetic flaw detection method is known as a flaw detection method for a wire rope that can be easily used to inspect the number of breaks of the wire rope in use. There are several types of this electromagnetic flaw detection method. For example, a wire rope is magnetized in the longitudinal direction using a permanent magnet, and a magnetic flux leaking from the broken portion of the wire rope is detected by a probe coil. Conventionally, an apparatus for inspecting the breakage of the sheet is known (see, for example, Patent Document 1).

  FIG. 3 is a block diagram showing a conventional example of such a wire rope flaw detector. As shown in FIG. 3, a conventional wire rope flaw detector 10 includes a U-shaped permanent magnet 11 and a probe coil 12, and a magnetic flux 13 generated from the permanent magnet 11 causes the length of the wire rope 14 to be long. The wire rope 14 is strongly magnetized along the direction. In this case, if the wire rope 14 is damaged, a leakage magnetic flux 13 a is generated at the damaged portion 15 of the wire rope 14. Then, when the wire rope 14 is moved in the longitudinal direction in this state, a minute voltage is generated in the probe coil 12 due to the linkage between the probe coil 12 and the leakage magnetic flux 13a. Therefore, by detecting this voltage, The number of breaks of the wire rope 14 can be measured.

  However, in this type of wire rope flaw detector 10, since the wire rope 14 is strongly magnetized by the permanent magnet 11 as described above, residual magnetism occurs in the wire rope 14 after measurement. This residual magnetism affects the leakage magnetic flux at the next measurement, and there is a possibility that the detected value changes every measurement. Moreover, there exists a possibility that iron powder etc. may adhere to the wire rope 14 by residual magnetism and the wire rope 14 may be damaged by friction with iron powder etc. Furthermore, since a plurality of wire ropes 14 are used in combination depending on the application, such as an elevator, the residual magnetism affects the behavior of the wire rope 14 and the wire rope 14 may vibrate. Therefore, it is necessary to demagnetize the residual magnetism of the wire rope 14.

  In order to demagnetize the residual magnetism of the wire rope 14, a wire rope flaw detector provided with the residual magnetism demagnetizer in the above-described flaw detector 10 has been proposed (for example, see Patent Document 2).

  FIG. 4 is a block diagram showing a conventional example of a wire rope flaw detector equipped with such a demagnetizer. As shown in FIG. 4, the flaw detection device 16 includes a detection device 17 that detects a leakage magnetic flux generated from a damaged portion of the wire rope 14 and a demagnetization device 18 that demagnetizes the residual magnetism of the wire rope 14. This flaw detection device 16 is used with a detection device 17 mounted on the outer periphery of the wire rope 14 and a demagnetization device 18 disposed behind the detection device 17 in the detection movement direction S. Here, the detection device 17 basically has the same principle as the flaw detection device 10 described above, and although the flaw detection device 10 is a U-shaped permanent magnet, it is configured by either a permanent magnet or an electromagnet. ing. Further, the demagnetizer 18 has a winding core 19 so as to surround the outer periphery of the wire rope 14, and the coil density on the front side in the detection movement direction S is large on the outer periphery of the winding core 19 and the coil density on the rear side is continuously small. Thus, the surrounding coil wire 20 is wound around. Furthermore, both ends of the surrounding coil wire 20 are connected to an AC magnet power source 22 via a conducting wire 21.

The flaw detection device 16 configured as described above includes a demagnetizing device 18 in addition to the detecting device 17, and the degaussing device 18 winds the surrounding coil wire 20 around the outer periphery of the winding core 19 disposed on the outer periphery of the wire rope 14. Therefore, the coil density can be continuously changed so that the coil density on the front side in the detection movement direction S is large and the coil density on the rear side is small. Thereby, since the hysteresis loop of the demagnetizing device 18 can be continuously reduced from the front side to the rear side in the detection movement direction S, the residual magnetism of the wire rope 14 can be demagnetized.
Japanese Unexamined Patent Publication No. 7-198684 JP 2005-162379 A

  By the way, in recent years, elevators have lost machine rooms, and machine room-less elevators in which hoisting machines are arranged in hoistways have become widespread. When doing so, it is necessary to install the flaw detectors 10 and 16 in the hoistway. However, there are few power outlets in the hoistway, and there are cases where there are no outlets in the vicinity to be measured. In particular, when using the flaw detector 16 as disclosed in Patent Document 2, in addition to the power source for the detector 17 Since an electromagnet is used for the demagnetizing device 18, the number of breaks of the wire rope 14 and the demagnetization of the residual magnetism are performed using at least two power sources, so that the power supply line is complicated. Therefore, the flaw detector 16 is difficult to use under this type of condition, and there is a problem that versatility is low.

  The present invention has been made in view of such a state of the art, and an object thereof is to provide a wire rope flaw detector having high versatility and high leakage flux detection accuracy.

  In order to achieve this object, the present invention comprises a magnetic flux detecting means for magnetizing a wire rope in the longitudinal direction and detecting a leakage magnetic flux thereof, and a degaussing means for demagnetizing residual magnetism of the wire rope, and the demagnetizing means. Comprises a plurality of magnetizers arranged at predetermined intervals along the longitudinal direction of the wire rope, and the magnetizers are composed of permanent magnets whose magnetic flux directions are orthogonal to the longitudinal direction of the wire rope, and adjacent to each other. The directions of the magnetic flux generated from the magnetizer are different from each other.

  In the wire rope flaw detector constructed in this way, it is not necessary to use a power source for the demagnetizing means composed of permanent magnets. be able to. In addition, the residual magnetism can be surely demagnetized by making the direction of the magnetic flux of the magnetizer constituting the demagnetizing means orthogonal to the longitudinal direction of the wire rope and making the directions of the magnetic flux generated from adjacent magnetizers different from each other. it can.

  The wire rope flaw detector according to the present invention is characterized in that the degaussing means is disposed at a position sandwiching the magnetic flux detection means along the longitudinal direction of the wire rope. If comprised in this way, even if a wire rope moves to which direction along the longitudinal direction, since it passes a demagnetizing means before measuring with a magnetic flux detection means, a wire rope is moved once along a longitudinal direction. It is possible to demagnetize the residual magnetism simply by making it possible to detect the leakage magnetic flux with high accuracy.

  In the wire rope flaw detector according to the present invention, each magnetizer is composed of a first permanent magnet and a second permanent magnet that are opposed to each other with the wire rope interposed therebetween, and the first and second permanent magnets. It is characterized in that the magnetic poles are reversed from each other. If comprised in this way, since a uniform magnetic field can be formed in the direction orthogonal to the longitudinal direction of a wire rope, a residual magnetism can be demagnetized much more reliably.

  Further, the wire rope flaw detector according to the present invention is characterized in that the first permanent magnet and the second permanent magnet are provided on the base of the non-magnetic material to be integrated. If comprised in this way, handling of a demagnetizing means can be made easy and the convenience can be improved.

  The wire rope flaw detector of the present invention is used even in places where there are few power outlets, such as in a hoistway of a machine room-less elevator, because it is not necessary to secure a power line by configuring the degaussing means with a permanent magnet. And versatility can be improved. Further, by arranging the magnetizers so that the magnetic flux generated from each magnetizer is orthogonal to the longitudinal direction of the wire rope and the directions of the magnetic flux generated from adjacent magnetizers are different from each other, the residual magnetism can be surely demagnetized. It is possible to improve the detection accuracy of the leakage magnetic flux.

  FIG. 1 is a configuration diagram of a wire rope flaw detector according to an embodiment of the present invention, and FIG. 2 is a perspective view showing a main part of a demagnetizing means of the flaw detector. is there.

  As shown in FIG. 1, a wire rope flaw detector 1 according to an embodiment of the present invention includes a magnetic flux detection means 2 and a pair of demagnetization means 3, and each demagnetization means 3 is arranged along the longitudinal direction of the wire rope 4. Thus, the magnetic flux detection means 2 is disposed at each position. The magnetic flux detection means 2 is basically the same principle as the conventional one described with reference to FIG. 3 and is not shown, but a permanent magnet that magnetizes the wire rope 4 along its longitudinal direction, and a wire A probe coil that detects leakage magnetic flux generated from a damaged portion of the rope 4 is integrated with the rope 4. As shown in FIG. 2, the demagnetizing means 3 includes a plurality of (for example, three) magnetizers 5 arranged at predetermined intervals along the longitudinal direction of the wire rope 4. It is composed of a pair of permanent magnets 6 and 7 facing each other. For convenience, the left permanent magnet row in FIG. 2 is referred to as a first permanent magnet 6, and the right permanent magnet row is referred to as a second permanent magnet 7. Here, in the first and second permanent magnets 6 and 7 that form a pair, the direction of the magnetic flux of the first stage magnetizer 5 from the bottom is the P direction, and the direction of the magnetic flux of the second stage magnetizer 5 is from the bottom. The magnetic fluxes of the Q direction and the third stage magnetizer 5 are arranged so as to face the P direction, and the directions of the magnetic fluxes generated from the adjacent magnetizers 5 are different from each other. Further, each magnetizer 5 composed of the first permanent magnet 6 and the second permanent magnet 7 is provided on a common base 8 made of a non-magnetic material, and is integrated, and further, the wire rope 4 The distance between the magnetizers 5 in the longitudinal direction is longer than the distance between the first permanent magnet 6 and the second permanent magnet 7.

  In the wire rope flaw detector 1 according to this embodiment, the degaussing device 3 is composed of a plurality of magnetizers 5 including a first permanent magnet 6 and a second permanent magnet 7, and the magnetic flux of each magnetizer 5. Is perpendicular to the longitudinal direction of the wire rope 4 and alternately changes in the P direction and the Q direction along the longitudinal direction of the wire rope 4, so that when the wire rope 4 is moved in the longitudinal direction, the wire rope 4 becomes Magnetization is alternately performed in the P direction and the Q direction, and the residual magnetism of the wire rope 4 can be surely demagnetized. In this way, the wire rope flaw detector 1 demagnetizes residual magnetism by the demagnetizing means 3 composed of a plurality of magnetizers 5 composed of the first permanent magnet 6 and the second permanent magnet 7. It is not necessary to secure the power line of the means 3, and it can be used even in places where there are few power outlets, such as in the hoistway of a machine room-less elevator.

  Moreover, since the demagnetizing means 3 configured in this way is arranged at a position sandwiching the magnetic flux detecting means 2 along the longitudinal direction of the wire rope 4, the wire rope 4 is in either direction along the longitudinal direction. Even if it moves to, since it passes through the demagnetization means 3 before measuring with the magnetic flux detection means 2, it can demagnetize a residual magnetism only by moving the wire rope 4 once along a longitudinal direction.

  Further, the demagnetizing means 3 is composed of a plurality of magnetizers 5 composed of a first permanent magnet 6 and a second permanent magnet 7, and each magnetizer 5 is provided on a nonmagnetic base 8 to be integrated. Therefore, handling of the demagnetizing means 3 is facilitated and convenience is increased.

1 is a configuration diagram of a wire rope flaw detector according to an embodiment of the present invention. It is a perspective view which shows the principal part of the degaussing means of this flaw detection apparatus. It is a block diagram which shows the prior art example of the flaw detector of a wire rope. It is a block diagram which shows the prior art example of the flaw detector of a wire rope provided with the demagnetizer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wire rope flaw detector 2 Magnetic flux detection means 3 Demagnetization means 4 Wire rope 5 Magnetizer 6 1st permanent magnet 7 2nd permanent magnet 8 Base

Claims (4)

  Magnetic flux detecting means for magnetizing the wire rope in the longitudinal direction and detecting the leakage magnetic flux, and degaussing means for demagnetizing the residual magnetism of the wire rope, the demagnetizing means having a predetermined interval along the longitudinal direction of the wire rope. A plurality of magnetizers arranged in a row, wherein the magnetizers are composed of permanent magnets whose magnetic flux directions are orthogonal to the longitudinal direction of the wire rope, and the magnetic flux directions generated from the adjacent magnetizers are different from each other. A wire rope flaw detector characterized by that.   The wire rope flaw detector according to claim 1, wherein the degaussing means is arranged at a position sandwiching the magnetic flux detection means along the longitudinal direction of the wire rope.   The wire rope flaw detector according to claim 1 or 2, wherein each of the magnetizers includes a first permanent magnet and a second permanent magnet that are opposed to each other with the wire rope interposed therebetween, and the first and second permanent magnets. A wire rope flaw detector characterized by reversing the magnetic poles of a magnet.   4. The wire rope flaw detector according to claim 3, wherein the first permanent magnet and the second permanent magnet are provided on a non-magnetic base to be integrated.

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