JPS6156903A - Magnetic scale - Google Patents

Abstract

PURPOSE:To secure the mechanical strength of a magnetic scale and to make it possible to form the scale with a material having a desired thermal expansion coefficient in an arbitrary shape, by magnetizing a magnetic recording medium, which is embedded in a part of a base body, and forming a magnetic lattice. CONSTITUTION:A main body 10 of a magnetic scale is formed by embedding a magnetic recording medium 2 along the longitudinal direction of the outer surface of a base body 1, which is formed in a cylindrical shape by iron. The magnetic recording medium 2 is formed by a magnetic material, which has a readily magnetizing axis in the direction of the thickness and has magnetic anisotropy. Magnetism Hs is provided along the specified axial length by the logitudinal magnetic recording. Magnetization for forming a magnetic lattice Hs is provided in each of neighboring regions along the axial direction of the magnetic recording medium 2, in the reverse directions one another.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic scale for measuring length using a magnetic grid.

[Summary of the invention]

The present invention provides a magnetic scale for measuring length using a magnetic grating, in which the magnetic recording medium on which the magnetic grating is formed is embedded in a base, thereby facilitating manufacture and improving mechanical durability. It is designed to improve the thermal expansion coefficient.

[Conventional technology]

2. Description of the Related Art Conventionally, magnetic scales in which a magnetic grating is formed on a magnetic recording medium have been widely used as measuring devices such as spindle-type magnetic scale devices for measuring various manipulated variables in machine tools.

In general, the magnetic scale described above is applied to a magnetic recording medium formed into a cylindrical shape from a rolled alloy type magnetic material exhibiting rolled magnetic anisotropy having a magnetic easy axis in the rolling direction, that is, in the axial direction. A magnetic lattice is formed by transverse magnetic recording by performing in-plane magnetization along the magnetic easy axis.

[Problem that the invention seeks to solve]

The magnetic material used as the magnetic recording medium that forms the primary magnetic scale is not only soft, but also has a thermal expansion coefficient (1'l x 1') of iron that forms various machine tools to which measuring devices are installed. Since it has a coefficient of thermal expansion larger than O-6/'c), it is necessary to take measures against measurement errors due to thermal expansion and restrictions on usage conditions. Therefore, it has been extremely difficult to manufacture a practical magnetic scale that can ensure the desired measurement accuracy while taking into account temperature changes in the actual usage environment, as well as mechanical durability. . In addition, since it is difficult to obtain a strong signal magnetic field with the magnetic lattice formed by the above-mentioned in-plane magnetization,
Signal reading is generally performed using a contact-type read head.
Mechanical wear damage cannot be avoided.

[Means for solving problems]

In order to solve the above problems, the magnetic scale according to the present invention is characterized in that a magnetic recording medium is embedded in the base along the longitudinal direction of the base, and a magnetic grating is formed on the surface of the base.

[For production]

In the magnetic scale according to the present invention, by magnetizing the magnetic recording medium embedded in a part of the base, the magnetic 1j
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It is possible to use a material made of a material having a desired temperature expansion coefficient and having an arbitrary shape while ensuring mechanical strength of .

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings showing one embodiment.

A first example showing an embodiment of a coaxial magnetic scale according to the present invention.
In the figure, the magnetic scale main body IO is constructed by embedding a magnetic recording medium 2 along the longitudinal direction on the outer periphery of a base body 1 formed of iron into a cylindrical shape.

The magnetic recording medium 2 is made of a magnetic material exhibiting magnetic anisotropy with an axis of easy magnetization in the thickness direction, for example, by performing magnetic heat treatment in a predetermined magnetic field after solution treatment.
Fe/CO exhibiting magnetic anisotropy depending on the direction of the magnetic field mentioned above
- It is made of a spinodal magnetic material such as a Cr-based alloy, and is embedded in the base 1 and subjected to surface finishing such as cylindrical polishing. The magnetic recording medium 2 is magnetized in its thickness direction, that is, in the direction of its easy axis of magnetization, and a magnetic field H3 is formed over a predetermined axial length by longitudinal magnetic field recording. The magnetization for forming the magnetic lattice Hs is performed in opposite directions for each region adjacent to each other in the axial direction of the magnetic recording medium 2. In this embodiment, each '' adjacent in the axial direction of the magnetic recording medium 2 is
As shown in FIGS. 2A and 2EB, which schematically show the magnetization state in the fr4 region, FIG. A
As shown in FIG. 2B, the magnetic grating Hs by longitudinal magnetic field recording is generated by magnetizing the coaxial magnetic scale body 10 in the radial direction.
is formed over the magnetic recording medium 2. The magnetic grating Hs based on longitudinal magnetic field recording can be strongly magnetized and generate a strong signal magnetic field, compared to a magnetic grating based on general in-plane magnetization, that is, transverse magnetic field recording. Further, as in this embodiment, the magnetic recording medium 2 is embedded in the base body 1 made of a material with high magnetic permeability, and the magnetic recording medium 2 is
By forming the magnetic grating Hs on the magnetic recording medium 2, the base body 1 acts as a magnetic path for the magnetic grating Hs formed on the magnetic recording medium 2, so that the signal magnetic field due to the magnetic grating Hs can be further strengthened. Furthermore, the coefficient of thermal expansion of the coaxial magnetic scale body 10 can be made close to the coefficient of thermal expansion of the material (generally iron) forming the machine tool, and measurement errors and usage restrictions due to temperature changes in the surrounding environment can be reduced. can.

Therefore, the embodiment with the above-mentioned configuration is most suitable as a magnetic scale in a non-contact measuring device that reads signals using a thin-film magnetic detection head such as a through-type multi-gap magnetic head or a ferromagnetic magnetic grating resistance element. be.

In the embodiment shown in FIG. 3, the magnetic scale main body 10A uses an iron core made of a high magnetic permeability material in the shape of a round bar as the base body 1, and embeds the magnetic recording medium 2 in the base body 1. A magnetic lattice Hs is formed on the magnetic recording medium 2.

In this embodiment, a magnetic recording medium 2 forming the magnetic grating Hs for a signal magnetic field is embedded in the base l, and
A magnetic recording medium 3 for the origin signal is embedded, and the magnetic recording medium 3 is magnetized by a magnetizing section 4 for the origin signal. Further, one end of the base 1 is provided with a shank portion 4 for attachment to a length measuring device (not shown) or a machine tool on which the length measuring device is mounted, and a key groove 5 is formed in the outer circumferential surface 4a of the shank portion 4. The scale main body 10A has a structure that can be formed to prevent rotation of the scale body 10A.

The magnetic scale main body 10A of this embodiment is applied to a spindle type length measuring unit, as shown in FIG. 4, for example.

In the embodiment of the spindle type length measuring unit 30 shown in FIG. 3. The signal magnetic field generated by the magnetic grating Hs magnetized in the magnetic recording medium 2 embedded in the thin film type detection hem. At the same time, the origin signal from the magnetizing section j4 magnetized in the area recording medium 4 embedded in the base 1 is detected by the detection head 31B for detecting the origin. There is. The origin signal from the magnetization unit 4 provides absolute origin information to the measured value by the magnetic grid Hs. Therefore, in this embodiment, absolute method measurement can be performed.

Each length measuring unit 30 in the embodiments described above is equipped with a mechanically durable coaxial magnetic scale main body 10A, so the magnetic scale main body can be used as a mechanical element together with an IOA measuring element, for example, for industrial use. robot,
The above coaxial magnetic scale body can be used as a spindle shaft of an actuator or cylinder, or a guide shaft of a moving platform when automating assembly machines, transport machines, construction machines, transportation machines, and other various mechanical devices. .

In each of the above embodiments, the magnetic recording medium 2 is embedded in the base 1 made of iron, which is a high magnetic permeability material, and the magnetic lattice Hs by NW +n field recording is formed in the magnetic recording medium 2. However, the present invention is not limited to the above-described embodiments; for example, a magnetic recording medium is embedded in a base made of a non-magnetic material, and a magnetic lattice by transverse magnetic field recording is formed in the magnetic recording medium. You can do it like this.

[Effects of the Invention] As is clear from the description of each of the above-mentioned embodiments, according to the present invention, the magnetic scale according to the present invention is capable of magnetizing the magnetic recording medium embedded in a part of the base. Since a magnetic lattice is formed, the mechanical strength of the magnetic scale is ensured, and the base body can be formed into any shape using a material with a desired coefficient of thermal expansion, and therefore, it can be used as desired. can fully achieve its objectives.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a partially cross-sectional perspective view of an embodiment of a magnetic scale according to the present invention, and FIGS. 2A and 2B show each side of the magnetization state of the magnetic recording medium in the above embodiment. FIG. FIG. 3 is a cross-sectional view showing another embodiment, and FIG. 4 is a longitudinal cross-sectional view of a main part showing the structure of a spindle type length measuring unit using the magnetic scale of the above embodiment. 1...Substrate 2...Magnetic recording medium 10, IOA...Coaxial magnetic scale Hs...Magnetic grating Patent applicant Sony Magnescale Corporation Representative Patent attorney Kodo Koike Sakae Tamura - Figure 1 Figure 2 A Figure 2 8 Figure 4 Procedure Neho (self-motivated) September 6, 1985 Director General of the Patent Office Uga Michibe 1, Indication of the Case 1985 Patent Application No. 1662. o, No. 0 2, Name of the invention Magnetic scale 3, Relationship with the case of the person making the amendment Patent applicant address 3-9-17 Nishigotanda, Tokyo Parts Store Name Sony Magnescale Co., Ltd. Representative Kazuo Nagaoka 4, Agent Address: 11, 2-6-4 Toranomon, Minato-ku, Tokyo 105
Mori Building 11th floor TEL (508)8266 (Main)
Vol. 6, "Detailed Description of the Invention" column 7 of the specification to be amended, Contents of the amendment (7-1) The statement from page 5, line 8 to line 10 of the same page of the specification: In the magnetic recording medium 2, as shown in FIG. 2B, "" is deleted. (7-2) From the 4th line on page 7 to the 6th line of the same page of the specification, "The description [shank part 4, ... key groove 5]" is replaced with "shank part 5, this shank part 5". The key groove 6 is corrected to the outer circumferential surface 5a of the key groove 6. (7,-3') The statement on page 7, line 13 of the specification:
In the magnetic scale main body 1'O"A," is deleted. <r-4) The description "area recording medium 4" on page 7, line 18 of the specification is corrected to "recording medium 3." (7-5) The description from page 8, line 7 to line 8 of the same page of the specification, ``The magnetic scale IOA'J is corrected to ``the magnetic scale IOA''. (7-6) The statement in the first line of page 9 of the specification “...
You can do it like this. '', add the following statement:

Claims (1)

[Claims] A magnetic scale characterized in that a magnetic recording medium is embedded in the base along the longitudinal direction of the base, and a magnetic lattice is formed on the surface of the base.