JP2592789B2 - Block-shaped magnetic label - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a magnetic guidance system for guiding a visually impaired person, an automatic guided vehicle, and the like while detecting a marker placed along a taxiway with a magnetic sensor. The present invention relates to a block-shaped magnetic label used.

(Prior Art) Unmanned guided vehicles are often used in factories, warehouses, golf courses, and the like for the purpose of transferring luggage. The movement of the automatic guided vehicle is performed, for example, by generating a magnetic field due to a low-frequency current flowing through the buried tow path wire on the left and right of the guided vehicle.
Detected by two pickup coils (sensors), a method of moving the transport vehicle so as to keep the distance between the tow path wire and the coil constant, or paint or sheet-like ferrite (marker) applied to the floor, There is an electromagnetic type that detects this marker with a sensor. Of course, other than this, there are an optical reflection system, a laser beam system, an image recognition system, and the like.

When applying such an induction method to a visually impaired person such as a blind person, a soft magnetic material is used as a marker, but the most commonly used soft magnetic magnetic marker at present is a ferrite powder made of cement. It is a molded product that is hardened by mixing it with resin, asphalt, or the like.

(Problems to be Solved by the Present Invention) However, these markers have insufficient sensitivity due to insufficient soft magnetic properties as a molded body. In order to maintain the sensitivity at a certain value, it is necessary to increase the filling ratio of the ferrite powder during molding (usually 60% by weight or more, preferably 80% by weight or more). However, there is a drawback that it is not possible to obtain a molded article having sufficient strength and technical difficulty. On the other hand, it has been experimented to use soft magnetic metal powder instead of ferrite powder.However, molded articles using these powders also have insufficient magnetic properties, have poor sensitivity as markers, and have problems with corrosion resistance. In particular, in the case of outdoor use where the use environment is severe, there are disadvantages such as deterioration of characteristics and the like.

(Means for Solving the Problems and Their Applications) It is an object of the present invention to provide a soft magnetic label with improved conventional drawbacks.

The soft magnetic induction method is a method in which a soft magnetic material is used as a magnetic label and detection is performed by a magnetic sensor. Since the excitation frequency is as high as several tens KHz, the magnetic marker is required to have high magnetic permeability in a high frequency range.

That is, in the case of the present invention, a soft magnetic material is solidified with a non-magnetic substance such as cement, resin or asphalt, and a flake-like amorphous soft material is used as the soft magnetic material used in a desired block-shaped magnetic marker. The use of magnetic metal enhances the magnetic sensitivity detected by the sensor. Further, since the amorphous metal used has high corrosion resistance, its characteristics are less deteriorated even when it is installed and used in a severe environment. In addition, in the case of the present invention, a desired sensitivity can be obtained with a relatively small mixing ratio by using a flake-like amorphous metal as the soft magnetic material. Therefore, the molded article has features such as high strength.

The magnetic marker of the present invention is characterized in that an amorphous metal having excellent magnetic properties is employed in place of the conventional ferrite powder in the soft magnetic material to be used.

However, simply replacing the ferrite powder with the amorphous metal powder did not improve the sensitivity and did not provide a labeled body having the desired properties. This is considered to be due to the fact that excellent magnetic properties, such as magnetic permeability, of the amorphous metal are reduced in the case of powder. It is difficult to harden the amorphous metal, which is most commonly marketed, into a ribbon (thin plate) with cement, resin or the like to form a molded body. As a result of various studies, the present inventors have adopted a flake-shaped amorphous soft magnetic metal having a desired size, thereby significantly improving the sensitivity as compared with a conventional ferrite label, and mixing with cement or resin. Thus, the present inventors have found that molding can be performed relatively easily, and succeeded in providing a magnetic label of an amorphous soft magnetic metal for the first time.

The desirable shape and dimensions of the flake amorphous metal employed in the present invention are those having a thickness of 5 to 100 μm, preferably 20 to 60 μm, and an aspect ratio of 10 to 15,000, preferably 100 to 2000. If the size is smaller than this, the magnetic sensitivity is inferior, and if it is larger, molding becomes difficult, which is not preferable.

The desirable mixing ratio of the flake-like amorphous metal to cement or resin, which is a solidified substance of the flake-like amorphous metal, is 60% or more, preferably 80% or more by weight when using conventional ferrite. The desired sensitivity can be obtained sufficiently with a mixing ratio of about 0.5 to 50% as compared with that of the above. If it is 0.5% or less, the detection sensitivity is reduced, and if it is 50% or more, kneading is difficult, so 0.5% to 50% is good, and preferably 5 to 20%. Further, it is preferable that the flakes are aggregated near the surface rather than being uniformly distributed on the marker. Further, in the present invention, the ratio of the solidified material such as cement or resin can be increased, so that the molding is easy and the strength of the obtained marker is large.

As described above, magnetic markers are used for guidance on roads and the like, and therefore are often used outdoors. Therefore, it is desired that the characteristics do not deteriorate even in a harsh environment such as when exposed to rain and wind. It is known that an amorphous metal is a material having excellent corrosion resistance among metal materials, and deterioration of characteristics is relatively small even in such a severe environment. In order to further reduce such a change with time, the composition of the amorphous metal to be used is selected, and the soft magnetic property is excellent and the corrosion resistance is good.
If a Fe-Co-Si system or the like is selected, a more desirable label can be obtained.

(Example) Amorphous metal flakes having a composition of Co _69.8 Fe _4.2 Si ₁₇ B ₉ (the number attached to the element symbol represents atomic% of the element) were produced by a cavitation method.

This cavitation method is disclosed in Japanese Patent Application Laid-Open No. 58-6907, but has a surface layer having a small leakage property to the molten metal, and supplies the molten metal to a roll surface rotating at high speed. After dividing the molten metal into fine molten metal droplets,
Subsequently, the molten metal droplets collide with a rotating metal body rotating at a high speed to rapidly solidify the molten metal droplets.

Zero magnetostriction Co-Fe-Si- with good corrosion resistance and high magnetic permeability
If the B type is selected, a more desirable label can be obtained.
In this structure, Fe was 3.5
-5.0 at% is desirable, and as a semimetal for obtaining an amorphous alloy, Si: 13 to 19 at% and B: 5 to 15 at% are preferable. The balance is Co.

The average thickness of this amorphous metal piece manufactured by such a cavitation method is 40 μm, and the aspect ratio is 300 to 7.
00.

22.5 g of this amorphous alloy flake was added and mixed in a mixture of cement 1 and sand 2 to prepare a block having a thickness of 300 mm × 300 mm × 10 mm.

When the detection distance of this block is measured with a white stick for magnetic guidance for the visually impaired, it is effective up to a height of 6 mm from the block surface and is sufficiently practical.

(Effects) The block-shaped magnetic marker according to the present invention has good sensitivity and is resistant to wind and rain, and thus is suitable for laying on general public roads, stairs, and the like, and thus is optimal as a marker for visually impaired persons.

Claims (1)

(57) [Claims] 1. A flake-shaped amorphous alloy having a thickness of 5 to 100 μm and an aspect ratio (a ratio of a maximum length to a maximum thickness) of 10 to 15,000 is converted into a solidified material having a weight ratio of at least 0.5 to 50%. What is claimed is: 1. A block-shaped magnetic marker, wherein a solidified substance is made of cement and sand, wherein said block-shaped magnetic marker is formed into a desired shape by being contained therein.