JPH0115003B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a magnetic scale used in a measuring device, and particularly to a method of manufacturing a long magnetic scale.

A magnetic scale used in a measuring device is provided with magnetic graduations at predetermined intervals (wavelengths). The measuring device uses this magnetic scale as a magnetic head or a ferromagnetic metal thin film element (hereinafter referred to as DME. For more information on this DME, see Japanese Patent Application No. 79655 filed by the present applicant).
The dimensions of the object to be measured are determined by detecting it with a detection element such as , and determining the amount of relative movement between the detection element and the magnetic scale.

By the way, when the measurement dimension is long, for example, about several tens of meters, the magnetic scale needs to be lengthened accordingly, but it is extremely difficult to manufacture such a long magnetic scale.

Therefore, it is conceivable to magnetize and form a magnetic scale on a long magnetic recording medium by a predetermined unit length, but the polarity of the magnetized parts that make up the magnetic scale must be alternately reversed, and this polarity problem is a problem. Another problem is to improve the accuracy of the interval between magnetic scales formed by unit length, and forming magnetic scales by unit length is not easy.

The present invention has been made in view of the above circumstances, and provides a method for manufacturing a long magnetic scale that can solve the problem of polarity of the magnetized part, improve the precision of the scale interval, and is easy to work with. The purpose is to provide.

An embodiment of the present invention will be described below with reference to the drawings. First, as a scale material, a magnetic recording medium layer made of a ferromagnetic material such as a rubber magnet, a plastic magnet, or an alloy magnet is used.
For example, a magnetic scale made of a high magnetic permeability material such as soft iron, stainless steel, permalloy or the like can be used, and the magnetic scale may be formed by adhering to a base, but the magnetic recording medium alone may constitute the magnetic scale. For example, a magnetic recording medium with a width of 20
A ribbon-shaped rubber magnet with a width of 20 mm and a thickness of 0.8 mm is used, and the high magnetic permeability material is a ribbon-shaped permalloy with a width of 20 mm and a thickness of 0.2 mm, and the two are bonded together to form a magnetic scale material. In this case, the magnetization step for forming the magnetic scale may be performed either before or after the bonding and fixing of the two.

FIGS. 1 and 2 show an embodiment in which magnetic graduations are formed by magnetization in a predetermined unit length on a ribbon-shaped magnetic recording medium 51 before bonding.
The magnetizer 60 is composed of a comb-like core 61 made of pure iron with high magnetic permeability, each protrusion 62 of which is provided with a coil 63 in which adjacent protrusions are wound in opposite directions. By vertically magnetizing the magnetic recording medium 51 with this magnetizer 60, a magnetic scale is formed by the unit length. The magnetic scale has an interval (wavelength: λ) of approximately 10 mm, and an integral number (n) of them are formed within this unit length, so that the unit length is nλ. The unit length is, for example, about 2 to 3 meters when the total length of the long magnetic scale is several tens of meters. To form a magnetic scale of nλ, a magnetizer 60
has an even number (2n) of magnetic poles with alternately different polarities, and the magnetic poles 62a and 62b at both ends have mutually different polarities. Two magnetic scale detection elements are arranged along this magnetizer 60, the distance between them being precisely fixed at an integral multiple mλ of the magnetic scale wavelength λ. In this embodiment, DMEs 56 and 57 are used as the magnetic scale detection elements.

First, as shown in FIG. 1, a long ribbon-shaped magnetic recording medium 51 is arranged so that one end (the left end in the figure) of each is aligned with the magnetizer 60, and the back surface of the recording medium 51 has a high magnetic permeability. A current is applied to the coil 63 while the material 52 is placed. Then, a magnetic field is formed as shown by the arrow, and the recording medium 51 is vertically magnetized at positions corresponding to the protrusions 62, and 2n magnetized parts 53 with different polarities are formed alternately in the longitudinal direction.
The unit length magnetic scale is magnetized. The magnetization directions of the magnetized portions 53a and 53b at both ends of this unit length are opposite to each other. Next, high magnetic permeability material 52
is temporarily removed to bring the pair of DMEs 56 and 57 closer to the back surface of the recording medium 51. At this time, for example, the DMEs 56 and 57 are moved by a small amount in the longitudinal direction of the recording medium 51 while the interval mλ between them is fixed, and the magnetic scale detection output of one DME 56 is adjusted to almost zero. At this time, the other DME 57 is placed at a position away from the magnetizer 60, as shown in FIG.

Next, while maintaining the relative positions of the magnetizer 60 and the DMEs 56 and 57, the long recording medium 51 on which the magnetic scale is formed by one unit length is fed approximately one unit length in the direction of arrow A in the figure. The unmagnetized portion of the recording medium 51 is placed on the magnetizer 60 to form the next one-unit length magnetic scale. At this time,
The DME 57 detects the previously formed magnetic scale, and the recording medium 51 is adjusted by moving a very small amount in the longitudinal direction so that the detection output of the DME 57 becomes zero (see FIG. 2). In this way, the interval between the magnetic scales at the joint between the previously formed magnetic scale of one unit length and the next magnetic scale of one unit length to be magnetized and formed can be set accurately. Generally, after
It is sufficient that the output of the DME 57 has the same value as the output of the previous DME 56. To achieve this, for example, a voltage detection circuit 58 consisting of three differential amplifier circuits 59 using OP amplifiers as shown in FIG. can be used. In this way, the magnetic scale interval at the joint can be set accurately, and the magnetization directions of the magnetized parts 53b and 53'a that are adjacent to each other through the joint are opposite to each other, so that the order of the magnetization directions of the magnetized parts is not disturbed. Incidentally, during the magnetization in FIG. 2, it is necessary to arrange the high magnetic permeability material 52 on the back surface of the recording medium 51 in the same way as described above. In addition, DME56,5
7 is not limited to detecting the magnetic scale only from the back surface of the recording medium 51, but may also be detected from other directions.

The long ribbon-shaped magnetic recording medium 51, in which the magnetic graduations of multiple unit lengths are formed at accurate constant magnetic graduation intervals in this way, is bonded and fixed to a high magnetic permeability material such as ribbon-shaped permalloy. magnetic scale can be constructed.

As described above with respect to the embodiments, according to the present invention, when magnetizing and forming a magnetic scale by one unit length on a long magnetic recording medium using a one unit length magnetizer, the magnetic scales are formed at both ends of the magnetizer. Since the polarity of the magnetic poles is reversed, the polarity of the magnetized parts at both ends of the magnetic scale of one unit length to be magnetized and formed is opposite, and even at the joint part with the adjacent magnetic scale of one unit length, The order in which magnetized portions with different polarities appear alternately in the longitudinal direction is not disturbed. Also,
For a 1-unit length magnetic scale that has been previously magnetized using two magnetic scale detection elements whose spacing is fixed at an integral multiple of the magnetic scale wavelength, the next magnetized scale is Since the position of the magnetizer is determined, accurate scale intervals can be maintained with a simple operation even at mutual joints of magnetic scales of one unit length. Therefore, a long magnetic scale with high precision can be easily manufactured.

[Brief explanation of drawings]

1 and 2 are schematic front views for explaining each step of a manufacturing method according to an embodiment of the present invention, and FIG. 3 is a circuit used in the steps shown in FIGS. 1 and 2. FIG. 3 is a circuit diagram showing an example. 51... Long magnetic recording medium, 53... Magnetization section,
56, 57...DME, 60...Magnetizer.

Claims (1)

[Claims] 1. A long magnetic recording medium is placed along a magnetizer of a predetermined unit length, which has a large number of magnetic poles with alternately different polarities, and the magnetic poles at both ends are of opposite polarity, and the medium is vertically magnetized to a predetermined value. 2 which forms a magnetic scale of wavelength and whose interval is fixed to an integral multiple of this wavelength.
The magnetic scale detection elements are positioned so that one element detects the magnetic scale that is currently magnetized and formed, and the other element is positioned so that it is located outside the range of the magnetic scale of the unit length that is currently magnetized and formed. and adjust the two magnetic scale detection elements by moving them in the longitudinal direction of the elongated magnetic recording medium so that the output of one of the elements becomes a predetermined value. The position relative to the ceramic is fixed, and then the elongated magnetic recording medium is moved in its longitudinal direction by approximately the unit length so that the magnetized and formed magnetic scale is detected by the other element. hand,
The position in the longitudinal direction of the long magnetic recording medium is determined so that the output of the other element is the same as the output of the one element, and then, at this position, the magnetic scale of the next unit length is set by the magnetizer. A method for manufacturing a long magnetic scale, which comprises forming a magnetic scale adjacent to a previously formed one unit length magnetic scale.