JPH11230945A - Magnetic flaw-detecting device of wire rope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the wearout of the contact part of a friction load or an excitation core when moving a wire rope, to omit bulk demagnetization operation being required when terminating damage detection operation, and to minimize the influence of the traveling speed of the wire rope. SOLUTION: In a magnetic flaw-detecting device, when a wire rope 3 being arranged near the tip part of main cores 1c and 1d and center detection cores 1a and 1b of both edges of an E-shaped core 1 being excited by excitation coils 2c and 2d is relatively moved in the longitudinal direction, and the damage of the surface of the wire rope 3 is detected by electromotive force being excited by detection coils 2a and 2b being wound on the detection cores 1a and 1b, AC power is supplied to the excitation coils 2c and 2d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a wire rope magnetic flaw detector for detecting mechanical damage on the surface of a wire rope or the like that suspends a car of an elevator.

[0002]

2. Description of the Related Art As technology advances, demands for product quality, life, and safety are increasing, and the technical field of elevators and other elevators is no exception. In particular, in the case of an elevator that moves with a passenger, if safety is impaired, a serious accident such as a personal injury may occur. Therefore, special considerations such as a requirement for periodic maintenance and inspection are given.
By the way, the wire rope that suspends the elevator car is a lifeline for the elevator, and whether or not the wire rope is damaged belongs to the highest rank in the judgment of the safety of the elevator. The wire rope of the elevator is hung over a grooved wheel and pressed against it, and bending and frictional forces are applied at all times, so that the strands with a diameter of about 1 mm that make up the twisted bundle are easy to break and one strand Since disconnection of a wire may cause local concentration of a load and induce chain disconnection of surrounding wires, early detection of a wire break is extremely important for safety of an elevator.

[0003] Therefore, conventionally, maintenance personnel have periodically inspected the wire rope visually to check for damage. However, it was difficult to find damage to the wire on the surface of the oil-coated wire rope, and the damage to the wire was sometimes overlooked. In addition, the number of floors at which the elevator is stopped increases along with the rise of buildings, and the length of wire ropes also increases, so that inspection work on wire ropes in such buildings has become more difficult.

In order to solve such difficulties in the prior art, the present inventors have made a new proposal for confirming whether or not the wire rope is damaged by using a magnetic flaw detector. 8 and 9 are a configuration diagram and an output waveform diagram, respectively, showing the principle of a magnetic rope flaw detector according to a conventional example. When a DC current flows through the two exciting coils 2c and 2d wound around the E-shaped iron core 1, the E-shaped iron core 1 is excited, and a main magnetic flux φ ₀ is generated. The main magnetic flux φ ₀ flowing out from one main magnetic core 1c flows into the wire rope 3 and mainly returns to the other main magnetic core 1d. The flow also returns to the branched detection magnetic cores 1a and 1b having the same gap. A polarization flux phi _a flow detection magnetic core 1a, and 1b flows out from the main magnetic core 1c is when there is no damage to the wire rope 3, detecting core 1
a, a polarized magnetic flux φ flowing out of the main magnetic core 1 d flowing out of the magnetic core 1 d
_{Since b} is in the opposite direction at the same flow rate, the polarization fluxes that actually cancel each other and actually flow through the detection magnetic cores 1a and 1b become 0, and no voltage is generated in the detection coils 2a and 2b.

[0005] However, if there is damage to the wire rope 3, the damaged portion is the main core 1c and the detection magnetic core 1a, upon reaching between 1b is a φ _a <φ _b by the magnetic resistance of the damaged portion Therefore, polarization magnetic flux (φ _b −
A substantial magnetic flux is generated at a flow rate of φ _a ). This allows
Detection coils 2a, detecting core 1a to 2b, the voltage proportional to the amount of change in substantial flux flowing 1b e _a, e _b is generated. Therefore, as shown in FIG.
lesion detection magnetic core 1a to b, the peak voltage e _a1, e _b1 opposite each at the time of passing through the 1b occurs, these synthetic output voltage e _m is generated according to the spacing between the flux lines The damage detection signal _em1 has the peak voltages e _a1 and e _b1 of the unevenness from which the noise component has been removed.

[0006]

As described above, in the prior art, the E-shaped iron core 1 is excited by the DC current flowing through the two exciting coils 2c and 2d wound therearound. Is strongly induced and attracted, and a large frictional force is generated between the wire rope 3 and the E-shaped iron core 1 at the time of movement. Therefore, the frictional load at the time of movement of the wire rope 3 is increased, and the contact portion of the E-shaped iron core 1 is worn. It becomes intense. Also, if the movement for detecting the damage of the wire rope 3 is interrupted for some reason or is significantly slowed down,
Since the wire rope 3 is magnetically recorded while being magnetized, in order to remove the obstacle of damage detection by this,
An AC magnetic field must be applied and degaussed each time the wire rope 3 damage detection work is completed. If the number of wire ropes 3 increases, the degaussing work places a heavy burden on maintenance personnel. Further, since the damage detection signal _em1 for detecting damage to the wire rope 3 is proportional to the moving speed of the wire rope 3, the detection accuracy decreases when the moving speed changes, and when the moving speed decreases by a certain degree or more, The damage detection signal _em1 becomes too small to be detected.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and there is little frictional load when the wire rope moves and wear of the contact portion of the exciting core, and degaussing at the end of the damage detection work. An object of the present invention is to provide a magnetic flaw detector for a wire rope that requires no work and is hardly affected by the moving speed of the wire rope.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention supplies an electric current to an exciting coil wound on an exciting core having at least two magnetic poles arranged in close proximity to a wire rope. An AC power supply is used as the power supply for the power supply. Preferably, two magnetic flaw detectors are arranged so that the magnetic poles of the excitation core and the detection coils face each other.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; FIG. 1 is a block diagram showing the principle of a magnetic rope flaw detector according to a specific example of the present invention, and FIG. 2 is a block diagram showing the internal configuration of a hoistway when the specific example is applied to an elevator. 3 is 2
FIG. 4 is a perspective view showing an arrangement state of two magnetic inspection apparatuses, FIG. 4 is a side view showing an arrangement state of the E-shaped iron core 1 and the detection magnetic cores 1a and 1b of the two magnetic inspection apparatuses, and FIG. FIG. 4 is a waveform diagram showing a damage detection signal. The same reference numerals are given to portions which are the same as or can be regarded as the same as those in the conventional example, and redundant description thereof will be omitted. In these figures, 4 is an elevator car, 5 is a driving steel car driven by a driving motor (not shown), 6 is a driven steel car on which a wire rope 3 is hung along with the driving steel car 5 and is rotatably mounted. , 7 is a counterweight attached to the end of the wire rope 3 opposite to the car 4 to balance the load of the car 4, 8 is an AC power supply, 10 is a floor close to the wire rope 3. It is a magnetic flaw detector attached to.

The detection coils 2a and 2b are connected in anti-parallel and connected to a tuning amplifier (not shown). In this specific example, two exciting coils 2c and 2d for exciting the E-shaped iron core 1 are provided.
Is connected to an AC power supply 8, and the E-shaped iron core 1 is AC-excited. Therefore, even if the moving speed of the wire rope 3 is reduced to some extent, the wire rope 3 is always maintained in a demagnetized state. No action is required. Further, since the wire rope 3 is not magnetized, it is not magnetically attracted to the E-shaped iron core 1 and therefore no large frictional force is generated between the wire rope 3 and the E-shaped iron core.

Further, since the E-shaped iron core 1 is AC-excited, the polarized magnetic fluxes φ _a and φ _b flowing through the wire rope 3 flow in a portion close to the surface thereof, and thus are generated by press contact with the steel wheels 5 and 6 or the like. Damage to the surface of the wire rope 3 can be effectively detected. Further, the detection coils 2a, 2
By synchronous detection combined output voltage e _m of b, moving from even the moving speed of the wire rope 3 is considerably reduced allowing detection of damage detection signal e _m1, maintenance personnel the wire rope 3 by the sender It is possible to perform accurate magnetic flaw detection even when performing the damage detection work,
Can be reduced in size and cost. As shown in FIGS. 3 and 4, the two magnetic flaw detectors 10 are connected to the ends of the main magnetic cores 1c and 1d of the E-shaped iron core 1 and the detection magnetic core 1d.
Since the U-shaped tips of (a, b) are arranged so as to face each other, damages occurring on both the upper and lower (or left and right) sides of the wire rope 3 can be slightly reduced. Can be detected efficiently by simply shifting the position.

FIG. 5 is a perspective view of a magnetic flaw detector according to another embodiment of the present invention, and FIG. 6 is a waveform diagram showing a damage detection signal measured by this embodiment. In this specific example, the detection coils 2a and 2b are constituted by air-core coils, and do not have a detection magnetic core to be interposed as in the above specific example. Therefore,
A decrease in impedance due to the presence of the detection core can be suppressed. In this specific example, the same effect as in the above specific example can be obtained.

[0013]

As described above, according to the first aspect of the present invention, since the AC power supply is used as a power supply for supplying a current to the exciting coil wound on the exciting core, the friction at the time of moving the wire rope is used. The wear of the load and the contact portion of the exciting core can be reduced, the degaussing work at the end of the damage detection work can be eliminated, and accurate damage detection can be performed even if the moving speed of the wire rope decreases. According to the second aspect of the present invention, since the two magnetic flaw detectors are arranged such that the magnetic poles of the respective excitation iron cores and the detection coils face each other, damages occurring on both sides of the wire rope can be prevented. Efficient detection can be achieved simply by slightly moving the movement position.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing the principle of a magnetic rope flaw detector according to a specific example of the present invention.

FIG. 2 is a configuration diagram showing the internal configuration of the hoistway of the elevator according to this specific example.

FIG. 3 is a perspective view showing an arrangement state of two magnetic flaw detectors.

FIG. 4 is a side view showing an arrangement state of an E-shaped iron core and a detection magnetic core of two magnetic flaw detectors.

FIG. 5 is a waveform chart showing a damage detection signal measured according to this specific example.

FIG. 6 is a perspective view of a magnetic flaw detector according to another embodiment of the present invention.

FIG. 7 is a waveform chart showing a damage detection signal measured by this specific example.

FIG. 8 is a configuration diagram showing the principle of a magnetic rope flaw detector according to a conventional example.

FIG. 9 is an output waveform diagram of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 E-shaped iron core 1a, 1b Detection magnetic core 1c, 1d Main magnetic core 2a, 2b Detection coil 2c, 2d Exciting coil 3 Wire rope 4 Riding car

Claims (2)

[Claims] 1. An exciting core having at least two magnetic poles disposed in close proximity to a wire rope, an exciting coil wound on the exciting core, a power supply for supplying a current to the exciting coil, A detection coil disposed between the two magnetic poles and configured to allow a polarized magnetic flux branched from a main magnetic flux passing through the wire rope through the two magnetic poles to pass through the inside thereof; In a magnetic rope flaw detector for detecting mechanical damage caused on the surface of the wire rope by an electromotive force excited by the detection coil by a relative movement of the wire rope in the longitudinal direction with respect to the excitation core, an AC power supply is used as the power supply. A magnetic flaw detection device for wire ropes, characterized by using: 2. The wire rope magnetic flaw detector according to claim 1, wherein the two magnetic flaw detectors are arranged such that the magnetic poles of the respective excitation iron cores and the detection coils face each other.