JP2544456B2 - Method of manufacturing magnetic scale - Google Patents

Description

The present invention relates to a method for producing a magnetic scale that can be used in a high temperature environment.

[Prior Art] FIG. 6 is a sectional view showing a conventional magnetic scale disclosed in, for example, Japanese Patent Publication No. 48-10655, "Magnetic Scale". In the figure, (6) is a rod-shaped base made of iron or an iron alloy such as Elinvar (trade name), and (7) is steel or aluminum formed by plating or clad on the surface of the base (6). A non-magnetic metal layer (8) is a magnetic layer such as cobalt-nickel formed on the non-magnetic metal layer (7).

[Problems to be Solved by the Invention] The conventional magnetic scale as described above is configured as described above. For example, as shown in Maruzen (1974), Metal Data Book; The coefficient of thermal expansion of Elinvar is 12.1 × 10 ^-6 and 8.0 × 10 ^{-6, respectively.}
And the coefficients of thermal expansion of steel and aluminum are
17.0 × 10 ^-6 and 23.5 × 10 ^-6 . The coefficient of thermal expansion of cobalt-nickel is, for example, S-816 (AISI 67) as shown in Heat Resistant Steel Data Book; Special Steel Club (1965).
In 1), it is 11.9 × 10 ^-6 .

In the structure as shown in FIG. 6, when the temperature rises to 100 ° C. or higher, the substrate (6), the non-magnetic metal layer (7) and the magnetic layer (8)
However, there is a problem that the non-magnetic metal layer (7) and the magnetic layer (8) are separated from the substrate (6) due to the different thermal expansion amounts. Even in the case of no peeling, thermal stress is applied to the base body (6), the non-magnetic metal layer (7) and the magnetic layer (8), the magnetic characteristics of the magnetic layer (8) deteriorate, and the sensitivity of the magnetic scale is reduced. There was a problem of lowering.

The present invention has been made to solve the above problems, for example, to obtain a method for producing a magnetic scale that is stable and has excellent measurement accuracy without deterioration in characteristics even when used in a high temperature environment. It is intended.

To achieve this object, Japanese Patent Application No. 62-217315 filed on Aug. 31, 1987 by the same applicant, “Method for producing heat-resistant magnetic scale” and Japanese Patent Application No. 62-217316 “ There is a method for manufacturing a heat-resistant magnetic scale ”. The former said, "A raw material of a different material is placed on a heat-resistant base material, and the raw material is mixed with the raw material at a desired interval to mix the raw material with the base material to change the magnetic characteristics of the heated portion. The method for producing a heat-resistant magnetic scale in which the Curie point of at least one of the base material and the heated portion is 100 ° C. or higher. ”The latter is“ heated portion by applying heat to the heat-resistant substrate at predetermined intervals. The Curie point of at least one of the base material and the heated portion, which has changed the magnetic properties of 10
A method for producing a heat-resistant magnetic scale having a temperature of 0 ° C or higher. ". However, in these cases, for example, the ferrite precipitation amount is not so large, the residual magnetization amount is small, and
The problem that the ratio was not high still remained.

Therefore, the present invention further has good detection sensitivity and high SN.
It is an object of the present invention to provide a method for producing a magnetic scale with which a ratio can be obtained.

[Means for Solving the Problems] A method for manufacturing a magnetic scale according to the present invention is a method in which a nonmagnetic austenitic stainless steel is superposed on a ferromagnetic steel, and the austenitic stainless steel side and a high energy density heat source are provided between them to form a desired gap. To melt and solidify at least a part of the austenitic stainless steel and ferromagnetic copper in the heated part to precipitate magnetic ferrite in which the ferromagnetic steel is melted in the austenitic stainless steel to form a magnetic lattice. It is something that is done.

[Operation] In the present invention, the ferromagnetic steel and the non-magnetic steel are superposed, and both are heated by the high energy density heat source from the non-magnetic steel side, and the ferromagnetic steel of the base is also melted in the heated portion to form the magnetic material. Precipitation of ferrite to form a magnetic grid and magnetic connection with ferromagnetic steel ensure good detection sensitivity.
A high S / N ratio makes it possible to manufacture a magnetic scale without problems such as characteristic deterioration even when used in a high temperature range. Further, the non-magnetic steel is firmly fixedly joined to the ferromagnetic steel when forming the magnetic grid.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view illustrating a method of manufacturing a magnetic scale according to an embodiment of the present invention. (1) is a plate-shaped ferromagnetic steel (for example, ferritic or martensitic stainless steel, JIS SUS410 or SUS430), and (2) is a plate-shaped austenitic non-magnetic stainless steel (for example, JIS SUS).
304) and (11) are substrates in which ferromagnetic steel (1) and non-magnetic steel (2) are superposed. Reference numeral (3) denotes a heating portion obtained by irradiating the substrate (11) with a high energy density heat source (20) such as a laser beam or an electron beam from the nonmagnetic steel plate (2) side at a desired interval to heat the substrate (11). ) At least a part of the non-magnetic steel (2) and the ferromagnetic steel (1) are melted and solidified. By the beam irradiation, the non-magnetic steel (2) is melted and solidified and mixed with the ferromagnetic steel (1). In other words, the ferromagnetic steel (1) is also melted and ferrite is precipitated and becomes a ferromagnetic body. Magnetic lattices are formed on the substrate (11) at predetermined intervals. At this time, the non-magnetic steel (2) is firmly fixedly joined to the ferromagnetic steel (1).

For example, SUS304 with a plate thickness of 1 mm is used as the non-magnetic steel (2), SUS410 with a plate thickness of 1 mm is used as the ferromagnetic steel (1), a CO2 laser is output as a high energy density heat source (20) at 1 kw, and a beam scanning speed is 2 m. When irradiated and heated under a condition of about / min, a melted part having a melt width of 1.2 mm and a melt depth of 1.5 mm is formed in the heated part (3). That is, a magnetic grid is formed inside the non-magnetic steel (2) of the heating portion (3) and magnetically connected by the ferromagnetic steel (1).

FIG. 2 is a side view showing the manner in which the amount of displacement is detected using the magnetic scale according to the embodiment of the present invention. In the figure, (5) is an element that detects the amount of magnetic flux, such as a Hall element, (4) is an exciting magnet, (30)
Is the magnetic flux. A current is passed through the exciting magnet (4) to form a magnetic field, and the amount of magnetic flux leaking from the magnetic lattice is determined by the hall element (5).
Etc. to detect. FIG. 3 is a graph showing the detected magnetic flux amount (Hall element output), in which the horizontal axis represents the displacement amount and the vertical axis represents the magnetic flux amount (Hall element output). Therefore,
As shown in FIG. 3, by arbitrarily selecting the interval of the magnetic grid formed on the substrate by irradiating the beam and using the exciting magnet and the element for detecting the amount of magnetic flux such as the Hall element as shown in FIG. The relationship between the displacement amount and the residual magnetization amount is obtained, and the displacement can be detected. Further, in this method, since the magnetic layer is formed in the non-magnetic substrate, the magnetic flux is detected in pulses as shown in FIG. 3, which is more stable than the conventional method and has a very high detection sensitivity.

Also, the Curie point of ferrite that exhibits magnetism is approximately 700 ° C.
Because it is high, it has excellent heat resistance.

Although the CO 2 laser is used in the above embodiment, another laser such as a YAG laser or an electron beam may be used, or another high energy density heat source such as plasma may be used.

In the above-mentioned embodiment, the beam irradiation condition is shown as an example, and it goes without saying that various conditions can be selected.

Furthermore, although stainless steel SUS304 or SUS410 was used as the substrate (11) in the above-mentioned examples, other non-magnetic austenitic stainless steels such as SUS316 and SUS309,
It goes without saying that other ferromagnetic steel may be used, and the shape may be another shape such as a cylinder such as a pipe or a column.

In the above embodiment, the magnet for excitation (4) and the element for detecting the amount of magnetic flux, for example, the hall element (5) are used for the detection, but as shown in the side view of FIG. Even if the magnetic scale is magnetized in advance by the electromagnet for magnetization (15) and the amount of magnetization remaining in the magnetic scale is detected by a sensor such as a Hall element as shown in the perspective view of FIG. The same relationship between the displacement amount and the detected magnetic flux amount as in FIG. 3 is obtained, and the displacement can be detected.

[Effects of the Invention] As described above, according to the present invention, non-magnetic austenitic stainless steel is superposed on ferromagnetic steel, and both are heated at a desired interval from the austenitic stainless steel side by a high energy density heat source, At least a part of the austenitic stainless steel and the ferromagnetic steel in the heated portion is melted and solidified to precipitate a magnetic ferrite in which the ferromagnetic steel is melted in the austenitic stainless steel to form a magnetic lattice. Therefore, there is an effect that it is possible to manufacture a magnetic scale which has a good detection sensitivity and a high S / N ratio without causing a problem such as characteristic deterioration even when used in a high temperature range.

[Brief description of drawings]

FIG. 1 is a perspective view showing a method of manufacturing a magnetic scale according to an embodiment of the present invention, and FIG. 2 is a side view showing a state of detecting a displacement amount using a magnetic scale according to an embodiment of the present invention. 3 is a graph showing the relationship between the amount of magnetic flux (Hall element output) detected by the method of FIG. 2 and the amount of displacement, FIG.
FIG. 5 is a side view showing a state in which a magnetic scale according to another embodiment of the present invention is magnetized, and FIG. 5 shows how a displacement amount is detected using a magnetic scale according to another embodiment of the present invention. FIG. 6 is a sectional view showing a conventional magnetic scale. In the figure, (1) is a ferromagnetic steel, (2) is a non-magnetic austenitic stainless steel, (3) is a heating part, (20)
Is a high energy density heat source. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masaharu Moriyasu 8-1-1 Tsukaguchi Honcho, Amagasaki City, Hyogo Prefecture Mitsubishi Electric Corporation, Research Institute of Industrial Science (72) Masayuki Kaneko 8-chome, Tsukaguchi Honcho, Amagasaki City, Hyogo Prefecture No. 1 Mitsubishi Electric Corporation Production Technology Laboratory (72) Inventor Seigo Hiramoto 8-1-1 Tsukaguchi Honcho, Amagasaki City, Hyogo Prefecture Mitsubishi Electric Corporation Production Technology Laboratory (72) Inventor Hideo Ikeda Amagasaki City, Hyogo Prefecture 8-1, 1-1 Tsukaguchihonmachi Mitsubishi Electric Corporation Materials Research Laboratory (72) Inventor Shunji Omura 8-1-1 Tsukaguchihonmachi, Amagasaki City, Hyogo Prefecture Mitsubishi Electric Corporation Materials Research Institute (72) Inventor Yoshihiro Sugiyama Hyogo Prefecture 8-1-1 Tsukaguchi Honcho, Amagasaki-shi, Materials Research Laboratory, Mitsubishi Electric Corporation (56) References Japanese Patent Laid-Open No. 62-227095 (JP, ) Patent Akira 61-134604 (JP, A) JP Akira 62-42003 (JP, A) JP Akira 62-222103 (JP, A) JP Akira 62-67112 (JP, A)

Claims (1)

(57) [Claims] 1. A non-magnetic austenitic stainless steel is superposed on a ferromagnetic steel, and both are heated at a desired interval from the austenitic stainless steel side by a high energy density heat source to heat the austenitic stainless steel and the strong portion of the heated portion. A method for producing a magnetic scale, wherein at least a part of magnetic steel is melted and solidified to precipitate magnetic ferrite obtained by dissolving ferromagnetic steel in the austenitic stainless steel to form a magnetic lattice.