JPS6363051B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a magnetic scale.

Conventional magnetic scales are plated on a non-magnetic substrate.
They were manufactured by depositing a magnetic layer by vapor deposition or sputtering, by applying magnetic powder, or by depositing a plate-like magnetic material.

Then, the detector was moved along the flat surface of the magnetic material to detect the position or measure the length.

However, in order to improve the detection accuracy, it is necessary to precisely process the flat part of the magnetic material, and if precision polishing or the like is performed for this purpose, the manufacturing cost increases. In addition, when grinding with a grinder to reduce manufacturing costs, the thin plate-shaped magnetic material formed on the non-magnetic substrate becomes separated from the non-magnetic substrate due to thermal effects, making it impossible to grind with high precision. It was hot.

On the other hand, if a thick round bar or square bar of magnetic material is used to enable grinding, it is possible to use Fe-Cr-Co system or Fe-Co-Mn-C system which uses Co element and has good magnetic properties. In the case of alloys, the material costs are high and are not desirable.

The present invention improves the above-mentioned drawbacks and provides an inexpensive method of manufacturing a magnetic scale.

The manufacturing method of the magnetic scale of the present invention is to form a groove along the longitudinal direction of a rectangular non-magnetic stainless steel material on a plane parallel to the longitudinal direction, place a magnetically hard magnetic metal wire in the groove, and roll it. This method of manufacturing a magnetic scale is characterized in that the wire rod and the non-magnetic stainless steel material are bonded together by pressure bonding, and the surface on which the magnetic metal wire is embedded is ground.

If the substrate in which the magnetic metal wire is embedded is non-magnetic,
Materials such as Al, Cu, or brass may be used, but stainless steel is preferable in terms of workability, strength, wear resistance, corrosion resistance, etc., and SUS303 or 304 materials according to Japanese Industrial Standards are preferable.

The width of the groove dug in the non-magnetic substrate is approximately the diameter or width of the magnetic metal wire to be embedded, and the depth of the groove is at least half the diameter or thickness of the wire and does not exceed 90% of the diameter or plate thickness of the wire. If the width of the groove is too wide or too deep for the wire to be embedded, the cold welding by rolling will be insufficient, and if it is too narrow or shallow, the wire will be welded outside the groove or the wire will stick to the non-magnetic substrate. Deformation may occur, making it impossible to obtain a good magnetic scale.

The magnetic metal wire used in the present invention preferably has a coercive force of 300 oersted or more so as not to be affected by external magnetic fields, and is preferably made of a material with a high residual magnetic flux density. When a magnetic head is used for detection, detection is possible even if the residual magnetic flux density is low to some extent, but in that case a great deal of effort is expended in positioning the magnetic scale and the magnetic head. Further, when using a magnetoresistive element, a somewhat high residual magnetic flux density is required. Sometimes, when the detector is moved at high speed to perform position detection, etc., it is desirable that the magnetic scale and the detector do not come into contact with each other, and in that case, the residual magnetic flux density of the magnetic metal wire needs to be high. Therefore, Fe-Cr-Co alloy, or alloy containing one or more of V, Ti, Mo, Si, Nb, and Al, or Fe-Co-Mn-C alloy, or this alloy containing Mo, An alloy magnetic material containing one or more of W, Si, B, V, Cr, and Ti is desirable, and Cu-Ni-
Fe-based magnetic materials are undesirable because of their low residual magnetic flux density.

In order to perform cold pressure welding, it is necessary to thoroughly clean the pressure welding surfaces to remove dirt.

The cold-welded composite is satisfactory as a magnetic scale when the magnetic metal wire is heat-treated to exhibit good magnetic properties, but the surface on which the magnetic metal wire is embedded is then ground to create a smoother magnetic scale. It is preferable to use a flat surface of the material.

When the magnetic scale obtained as described above is used as a guide shaft for moving the detector using a non-magnetic substrate, it can function as both a magnetic scale and a guide shaft in one piece, thereby saving parts and simplifying the structure. It is also clear that the present invention is useful and reduces the cost of the device.

Fe-Cr-Co system or Fe-Co-Mn used
- The diameter of the C-based magnetic metal wire is as follows when using a general detection head or magnetoresistive element:
A diameter of 0.5 mm or more is sufficient; if it is too thick, a magnetic metal wire using the expensive Co element becomes expensive, so a magnetic metal wire that does not exceed 3 mm is appropriate.

Next, the magnetic scale of the present invention and its manufacturing method will be explained by way of examples.

Example 1 A groove as shown in Fig. 1a, 3 mm wide and 2 mm deep, was dug in a straight line on one side of a rectangular SUS300 material measuring 20 mm square and 1000 mm long. The inside of the groove is 3mm wide and 3mm thick.
21%Cr-15%Co-1.5%Ti-2%V-
The remaining Fe wire was thoroughly cleaned, the wire was embedded in the groove in an environment where dirt would not adhere to the inside of the groove and the wire, and after cold welding and rolling to form a composite, it was heated at 620°C in a hydrogen atmosphere. The heat treatment was carried out between 500°C and 500°C with gradual cooling at a rate of 20°C/hour. The heat-treated composite was fixed with the groove facing upward, and while being cooled with liquid, the surface on which the wire was to be embedded was ground using a precision grinder to a flat surface with H = 19.5 mm as shown in Figure 2a. The embedded magnetic metal wire did not come loose from the groove, and a good flat surface of the magnetic material was obtained.

Example 2 A groove 0.5 mm wide and 0.3 mm deep as shown in Fig. 1b was dug linearly on one side of a rectangular SUS304 material measuring 6 mm square and 1000 mm long. The weight ratio of the inside of the groove and the diameter of 0.5 mm is 38.025%Co-19.512%Mn-0.585%C-
The wire consisting of 1.366%Si-0.488%V-remaining Fe is thoroughly cleaned, and in an environment where dirt does not adhere to the inside of the groove and the wire, the wire is embedded in the groove and subjected to cold welding rolling to form a composite. After that, heat at 450℃ in hydrogen atmosphere.
Heat treatment was performed for 30 minutes. After that, the wire embedded surface was ground to a flat surface as shown in Figure 2b using a precision grinder.The rolled surface of the magnetic metal wire was almost in the same plane as the SUS304 material, and the surface smoothness was also good and the magnetic scale It was sufficient.

Example 3 A groove as shown in Figure 1a, 1.5 mm wide and 1.2 mm deep, was dug in a straight line on one side of a rectangular SUS303 material measuring 10 mm square and 1000 mm long. Inside the groove, width 1.5mm, thickness
A wire with the same composition as the magnetic metal wire used in Example (2) of 1.5 mm was thoroughly cleaned, the wire was embedded in the groove in an environment where dirt would not adhere to the inside of the groove and the wire, and cold welding was carried out. After applying heat treatment to form a composite, heat treatment was performed at 450°C for 30 minutes in a hydrogen atmosphere. The rolled surface of the magnetic metal wire was almost on the same plane as the SUS300 material, and the plane had good smoothness. However, in order to obtain an even better flat surface, the groove part was fixed facing upward, and the surface where the wire was embedded was ground using a precision grinder while being cooled with liquid so that H = 9.9 mm as shown in Figure 2 a. did. The embedded magnetic metal wire did not come loose from the groove, and a good flat surface of the magnetic material was obtained.

When the magnetic scales manufactured in Examples 1 to 3 were magnetically written at regular intervals and read using a detection magnetic head or a magnetoresistive element, detection signals were obtained at the same intervals as the writing intervals.

Note that the heat treatment conditions shown in the examples are not limited to these, and may be changed as appropriate depending on the materials used and various other conditions.

[Brief explanation of drawings]

Figures 1a and 1b show the shapes of grooves dug in the stainless steel non-magnetic substrate of the present invention, where W indicates the width of the groove and h indicates the depth. FIGS. 2a and 2b are cross-sectional views of the magnetic scales manufactured in Examples 1 to 3. Note that 1 in the figure indicates a groove formed in the non-magnetic substrate, and 2
is the magnetic metal wire fixed in the groove, and W and h are the width and depth of the groove.

Claims (1)

[Claims] 1. A magnetically hard magnetic metal wire is placed in a groove formed along the longitudinal direction of a rectangular non-magnetic stainless steel material in a plane parallel to its longitudinal direction, and rolled to separate the wire and non-magnetic stainless steel. 1. A method for manufacturing a magnetic scale, which comprises crimping and bonding a magnetic metal wire to a metal wire, subjecting it to heat treatment, and then surface-grinding the surface on which the magnetic metal wire is embedded.