JPH04207004A - Sensor with magnetic film and its manufacture - Google Patents

Abstract

PURPOSE:To give a uniaxial form magnetic anisotropy to the magnetic material of magnetic films so as to improve the residual magnetization and coercive force of the magnetic films as well as the magnetic signal writing property by forming a plurality of grooves into the magnetic films nearly along the detecting direction of magnetic signal detecting heads. CONSTITUTION:Since a plurality of grooves 6 composed of one spiral groove 6 are formed nearly along the detecting direction of magnetic signal detecting heads 4 and 4 on the surface of magnetic films 3 formed around the surface of a turbine shaft 2 at a prescribed interval in the axial direction of the shaft 2 near the central part of the shaft 2, the aspect ratio of the magnetic material A of the films 3 and 3 between the major and minor axis directions becomes larger and uniaxial form magnetic anisotropy is given to the material A in a direction which is almost parallel with the detecting direction of the heads 4 and 4. Therefore, the magnetic signal writing property of the films 3 and 3 can be improved, since the axis of easy magnetization is oriented in the length direction of the grooves 6 and flux reversal becomes easy to occur when a magnetic field is impressed.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for manufacturing a sensor having a magnetic film, and more specifically, a method for measuring the torque, rotation speed, rotation angle, etc. applied to a ring-shaped base material with high precision. Concerning what has been made possible.

(Prior Art) Conventionally, as a sensor having a magnetic film, a method is known in which a magnetic film is formed on a shaft-shaped base material and the applied torque is measured using the magnetic properties of the film.

For example, in Japanese Unexamined Patent Publication No. 61-53504, a magnetic film is formed on the surface of a rotating body shaft by spraying and coating a solution of a dissolved magnetic material.

(Problem to be Solved by the Invention) In recent years, magnetic recording media used in audio, VTR, etc. have been developed by coating a polymer film with a magnetic material such as γ-Fe2O3 to form a magnetic film. are doing.

In this case, the shape magnetic anisotropy of the magnetic material is utilized to improve the writeability of magnetic signals.

In other words, when coating a film with a magnetic material, a magnetic field is applied to orient the needle-like crystals such as γ-Fe2O3 in the longitudinal direction of the film to align the axes of easy magnetization, thereby increasing the magnetic flux density. B showing the relationship between and the magnetic field
The squareness ratio (residual magnetization/saturation magnetization) of the hysteresis loop of the -H curve is also improved, and both the residual magnetization and the coercive force are improved.

However, when forming a magnetic film by thermal spraying, the magnetic material as thermal spray powder is heated to a melting state or a state close to it, so that it exceeds the Curie point and becomes a paramagnetic state. Therefore, it is difficult to orient the magnetic material and align the axes of easy magnetization by applying a magnetic field during thermal spraying.

The present invention has been made in view of the above, and its purpose is to form a magnetic film and improve the magnetic film so that the axis of easy magnetization of the magnetic material of the magnetic film is oriented in a desired direction. This imparts uniaxial shape magnetic anisotropy to the magnetic material of the magnetic film, thereby improving the writeability of magnetic signals and improving both residual magnetization and coercive force.

(Means for Solving the Problem) In order to achieve the above object, the solution taken by the invention according to claim (1) is that a magnetic film capable of recording magnetic signals is formed on the surface of the base material, and the magnetic film is The present invention is based on a sensor having a magnetic film in which a magnetic signal detection head detects a magnetic signal recorded on the film. A plurality of grooves are formed in the magnetic film substantially along the detection direction of the magnetic signal detection head.

In addition, the solution taken by the invention according to claim (2) is a method for manufacturing a sensor having a magnetic film, in which a magnetic film capable of recording magnetic signals is formed on the surface of a base material, and then recording is performed on the magnetic film. The structure is such that a plurality of grooves are formed in the magnetic film substantially along the detection direction of the magnetic signal detection head for detecting the magnetic signals generated.

In addition, the solution taken by the invention according to claim (3) is a sensor having a magnetic film and a manufacturing method thereof.
) Width 0. A sensor having a magnetic film according to claim 1 or claim 2, wherein the magnetic film is 1 to 1, Qmm, and a method for manufacturing the same.

Furthermore, the solution taken by the invention according to claim (4) is:
A sensor having a magnetic film and a method for manufacturing the same according to claim (1) or claim (a), wherein the groove has a depth of 0.2 mm or more.

(Function) With the above configuration, in the invention according to claims (1) and (a), a plurality of grooves are formed in the magnetic film formed on the surface of the base material substantially along the detection direction of the magnetic signal detection head. Therefore, the multiple grooves increase the axial ratio between the long axis and short axis of the magnetic material, and the magnetic material of the magnetic coating has a large axial ratio.
Uniaxial shape magnetic anisotropy approximately along the detection direction of the magnetic signal detection head is imparted. Therefore, the axis of easy magnetization of the magnetic material is oriented in the longitudinal direction of the groove, and magnetization reversal occurs more easily when a magnetic field is applied, resulting in good writing performance of magnetic signals.

Furthermore, due to the plurality of grooves as described above, the axis of easy magnetization of the magnetic material is oriented in the longitudinal direction of the grooves, so that the squareness ratio of the hysteresis loop of the B-H curve indicating the relationship between magnetic flux density and magnetic field is also increased. Both residual magnetization and coercive force are increased.

In addition, in the invention according to claim 21, after forming a magnetic film on the surface of the base material, a plurality of grooves are formed in the magnetic film substantially along the detection direction of the magnetic signal detection head, so that the magnetic material is A plurality of grooves that increase the axial ratio between the long axis direction and the short axis direction can be easily and reliably formed.

Further, in the invention according to claim (3), the width of the groove is 0°1 to
Since it is 1.0 mm, the axial ratio of the long axis direction and the short axis direction of the magnetic material is larger, and the magnetic material has a uniaxial shape approximately along the detection direction of the magnetic signal detection head. By oriented the axis of easy magnetization of the magnetic material in the longitudinal direction of the groove, magnetization reversal occurs more easily when a magnetic field is applied, and the writability of magnetic signals is further improved.

Also, since the width of the groove is 0.1 to 1.0 mm,
The squareness ratio of the hysteresis loop is further increased, and the residual magnetization and coercive force are further increased.

Furthermore, in the invention according to claim (4), the depth of the ξ groove is 0.
Since it is 2 mm or more, it does not interfere with improving the axial ratio of the long axis direction and the short axis direction of the magnetic material. This ensures that the axis of easy magnetization of the magnetic material is oriented in the longitudinal direction of the groove, and that the squareness ratio of the hysteresis loop is also increased to ensure that the residual magnetization and coercive force are increased.

(Example) Embodiments of the present invention will be described below based on the drawings.

In FIGS. 1 and 2 showing a sensor having a magnetic film, 1 is a well-known sensor having a magnetic film, and this sensor 1 is attached to an aluminum turbine shaft 2 (base material) in a torque converter device (not shown). It was applied. Approximately at the center of the surface of the turbine shaft 2, coatings of 100 μm in thickness are provided at predetermined intervals in the axial direction and extend over the entire circumference.
m magnetic films 3, 3 are formed. The above magnetic film 3
3 is made of a magnetic material A having a magnetic function.

In this case, the magnetic material A is appropriately selected from cobalt powder, iron oxide (Fe30s) powder, etc., which have magnetic functions. The above-mentioned magnetic material A consists of magnetic particles granulated to a particle size of 10 to 44 μm. Then, using the magnetic particles as thermal spray powder, the magnetic coating is applied by plasma spraying over the entire circumference of the turbine shaft 2 from a direction substantially perpendicular to the portions spaced at a predetermined interval in the axial direction at approximately the center of the surface of the turbine shaft 2. 3.3 is formed. In addition, as a method for granulating the magnetic particles, an atomization method, a granulation method, a pulverization method, etc. are used.

The surfaces of the magnetic coatings 3, 3 are arranged so as to substantially follow the detection direction of a magnetic signal detection head 4.4, which will be described later.

Head surface 4a of the magnetic signal detection heads 4, 4.

6. Grooves that appear to be multiple stripes relative to 4a. ... is formed. This groove 6. ... consists of a single spiral groove 6 that goes around the surface of the magnetic films 3, 3. In addition, the groove 6
The width of is formed to be 0.1 to 1.0 mm, and
The depth of the groove 6 is 0.2 mm.

Further, a magnetic coating 3 is provided on the outside of the turbine shaft 2.
, 3, a pair of magnetic signal reading heads 4, 4 are arranged. In this case, magnetic signals are written to the magnetic coating 3.3 of the turbine shaft 2 by a pair of magnetic signal recording heads (not shown) that contact the magnetic coating 3.3 of the turbine shaft 2 rotating at 600 rps. ), a rectangular pulse signal (recording signal A and recording signal B) as shown in FIG. 3 is written at 15V over the entire circumference, and then the magnetic signal detection head 4.
4 is placed.

When torque acts on the turbine shaft 2, as shown in FIG. 4, the respective detection signals (recorded signals A and B) detected by the magnetic signal detection head 4.4 are sent to signal processing s11.

In this signal processing section 11, the magnetic signal detection head 4
, 4 are subjected to signal processing by individual signal processing means 12° 12, and then a phase difference signal between the magnetic signal detection heads 4 and 4 (between the magnetic films 3 and 3) is calculated by the phase difference calculation means 13. Then, the torque calculation means 14 calculates the torque necessary to eliminate the phase difference between the magnetic signal detection head 4.4, and outputs this torque so that the torque shock during gear shifting is alleviated. There is.

Note that methods for forming the magnetic films 3, 3 on the surface of the turbine shaft 2 include a plasma spraying method, a coating method, a plating method, and the like.

Next, an example of a method for manufacturing the magnetic films 3, 3 will be explained.

First, in the first step, magnetic particles made of the above-mentioned magnetic material A are granulated to a particle size of 10 to 44 μm. In addition, as a method for granulating the magnetic particles, an atomization method, a granulation method, a pulverization method, etc. are used.

Next, in a second step, the magnetic particles granulated in the first step are used as thermal spray powder, and are sprayed onto the shaft of the turbine shaft 2 at predetermined intervals in the axial direction at approximately the center of the surface of the turbine shaft 2. A magnetic film 3.3 is formed by spraying the magnetic film 3.3 by plasma spraying from a direction substantially perpendicular to the core so as to cover the entire circumference. Note that methods for forming the magnetic film on the surface of the turbine shaft include a plasma spraying method, a coating method, a plating method, and the like.

Then, in the fourth step, the surfaces of the magnetic films 3.3 formed on the turbine shaft 2 in the second step are coated with a lathe or the like while the turbine shaft 2 is rotated around its axis. A single spiral groove 6 is formed.

At that time, the width of the groove 6 was set to 0. 1 to 1.0 mm is because the axial ratio of the long axis direction and the short axis direction of the magnetic material is made larger, so that uniaxial shape magnetic anisotropy approximately along the detection direction of the magnetic signal detection head is obtained. It is added to the magnetic material of the magnetic film to orient the axis of easy magnetization of the magnetic material in the longitudinal direction of the groove, making it easier to cause magnetization reversal when a magnetic field is applied, and increasing the squareness ratio of the hysteresis loop. This is to make it happen.

In addition, the depth of the groove 6 is set to 0.2 mm because it is uniaxial, which runs approximately along the detection direction of the magnetic signal detection head, without impeding the improvement of the axial ratio between the long axis direction and the short axis direction of the magnetic material. This is to ensure that the axis of easy magnetization of the magnetic material is oriented in the longitudinal direction of the groove by imparting shape magnetic anisotropy to the magnetic material of the magnetic coating.

Further, the magnetic film 3 described above is widely used in the mechatronics field such as automobiles, machine tools, and industrial angle robots.

Therefore, in the above embodiment, the magnetic coatings 3.3 formed at predetermined intervals in the axial direction at the substantially central part of the surface of the turbine shaft 2 are coated so as to be substantially along the detection direction of the magnetic signal detection heads 4, 4. A plurality of grooves 6 consisting of a single spiral groove 6 surrounding the surface of the magnetic coating 3.3. ... are formed, so that a plurality of grooves 6. ..., the axial ratio of the long axis direction and the short axis direction of the magnetic material A in the magnetic coatings 3, 3 becomes large, and the magnetic material A of the magnetic coatings 3, 3...
Uniaxial shape magnetic anisotropy substantially along the detection direction of the magnetic signal detection head 4 is imparted. Therefore, the axis of easy magnetization of the magnetic material A is the groove 6. ... is oriented in the longitudinal direction, magnetization reversal occurs more easily when a magnetic field is applied, and writing performance of magnetic signals can be improved. Moreover, since the width of the groove 6 is 0.1 to 1.0 mm, the axial ratio between the long axis direction and the short axis direction of the magnetic material A becomes larger, and the width of the magnetic material A is approximately 0.1 mm to 1.0 mm. By imparting uniaxial shape magnetic anisotropy to the magnetic material A of the magnetic coatings 3, 3 and orienting the axis of easy magnetization of the magnetic material A in the longitudinal direction of the groove, magnetization reversal occurs when a magnetic field is applied. This becomes even more likely to occur, and the writability of magnetic signals can be further improved.

Also, a plurality of grooves 6 as described above may be used. Because the axis of easy magnetization of magnetic material A is oriented in the longitudinal direction of the groove, the squareness ratio (residual magnetization Br/saturation magnetization Bs) of the hysteresis loop of the B-H curve showing the relationship between magnetic flux density and magnetic field is ) is also increased, both residual magnetization and coercive force are improved, and the reproduction output after reproduction can be improved. Moreover, the width of the groove 6 is 0. Since it is 1 to 1 Omm, the squareness ratio of the hysteresis loop is further increased, the residual magnetization and the coercive force are further increased, and the reproduction output during measurement can be further improved. Moreover, the depth of the groove is 0. Since it is 2 mm or more, the uniaxial shape magnetic anisotropy substantially along the detection direction of the magnetic signal detection head can be maintained in the magnetic film without hindering the improvement of the axial ratio between the long axis direction and the short axis direction of the magnetic material. This will ensure that the axis of easy magnetization of the magnetic material is oriented in the longitudinal direction of the groove, and the squareness ratio of the hysteresis loop will also be increased, ensuring that the residual magnetization and coercive force are increased, and the It is possible to reliably improve reproduction output.

Furthermore, after forming the magnetic coatings 3, 3 at a predetermined interval apart in the axial direction of the surface of the turbine shaft 2, the magnetic coatings 3, 3 are formed substantially along the detection direction of the magnetic signal detection heads 4, 4. A plurality of grooves 611 consisting of a single spiral groove 6 that goes around the surface of the groove 611. are formed in the magnetic coatings 3, 3, so that the plurality of grooves 6. and 6.. are formed in the magnetic films 3, 3, so that the axial ratio of the long axis direction and the short axis direction of the magnetic material A is increased as described above. ... can be easily and reliably formed.

Next, a first test conducted to confirm the effect of the magnetic film 3.3 will be explained based on FIGS. 5 and 6.

First, an aluminum shaft member S with a diameter of 30 mm
, and a magnetic coating 3 with a thickness of 200 μm was formed on each surface of a plate T measuring 5 mm long, 5 mm wide, and 1 mm thick by a thermal spraying method using Fe203- as a thermal spray powder and using a plasma arc as a heat source.

Next, grooves were formed on the surface of the magnetic film 3 using a lathe under the conditions shown in Table 1.

Table 1 Then, using a VSM device (vibrating magnetometer), the plate material T
Groove spacing for samples ■ to ■ in (film thickness for sample ■)
The squareness ratio characteristics for each were measured, and the results shown in FIG. 7 were obtained.

In addition, in the shaft member S, a magnetic signal is written to the magnetic film while changing the distance between the magnetic signal recording head and the magnetic film as appropriate, and the distance between the magnetic signal detection head and the magnetic film is kept constant during reproduction. In this state, the reproduction output characteristics with respect to the distance between the magnetic signal recording head and the magnetic film were measured, and the results shown in FIG. 8 were obtained.

In this way, by setting the interval between the grooves, that is, the width in the transverse direction of the magnetic material of the magnetic coating, to 0.1 to 1.0 mm,
Materials where the squareness ratio of the hysteresis loop is not grooved■
It was confirmed that there was an improvement compared to . This results in
The writability of magnetic signals as well as residual magnetization and coercive force will all be improved.

It was also confirmed that the shorter the distance between the magnetic signal recording head and the magnetic film, the better the reproduction output during measurement, and the most preferable groove spacing was 0°5 mm as in sample ①, followed by 0.2 mm for sample ■, 0.8 for sample ■
mm, 1°2 mm for sample ■, and finally 0.2 mm for sample ■.
It will be 1mm.

Next, a second test conducted to confirm the effect of the magnetic films 3, 3 will be explained.

In this second test, the depth C of the groove in the plate material T and shaft member S used in the first test was set under the conditions shown in Table 2. In this case, the distance between the magnetic signal recording head and the magnetic film is 0.2 mm.

Table 2 Then, the reproduction output characteristics with respect to the groove depth of each of the samples 1 to 2 were measured, and the results shown in FIG. 9 were obtained.

In this way, it was confirmed that by setting the groove depth to 0.2 mm or more, the reproduction output characteristics became almost constant around 5V.

In addition, in the above examples and test examples, the turbine shaft 2, shaft member S, and plate material T made of aluminum were used, but the turbine shaft, shaft member, and plate material made of magnetic materials such as iron may also be used. In this case, a nonmagnetic film made of a nonmagnetic material such as aluminum is formed on the surface, and then a magnetic film is formed over the nonmagnetic film.

In the above embodiments and test examples, the groove 6. is formed on the surface of the magnetic film 3.3. ... is a single spiral groove, but it may be a plurality of individual annular grooves.

(Effects of the Invention) As described above, according to the sensor having a magnetic film of the invention according to claim (1), the magnetic film on the surface of the base material has a plurality of grooves substantially along the detection direction of the magnetic signal detection head. , the axial ratio of the long axis and short axis of the magnetic material is increased by the plurality of grooves, and the uniaxial shape magnetic anisotropy approximately along the detection direction of the magnetic signal detection head is created in the magnetic film. The axis of easy magnetization of the magnetic material is oriented in the longitudinal direction of the groove, making it easier to cause magnetization reversal when a magnetic field is applied, improving the writing performance of magnetic signals, and reducing the hysteresis loop. By increasing the squareness ratio, both residual magnetization and coercive force can be increased, and reproduction output during measurement can be improved.

Further, according to the method for manufacturing a sensor having a magnetic film according to the invention according to claim (2), after forming a magnetic film on the surface of the base material, the magnetic film is coated with the magnetic film along the detection direction of the magnetic signal detection head. Since a plurality of grooves are formed in this manner, it is possible to easily and reliably form a plurality of grooves that increase the axial ratio between the major axis direction and the minor axis direction of the magnetic material.

Further, according to the sensor having a magnetic film and the manufacturing method thereof according to the invention according to claim (3), the width of the groove is 0°1 to 1.0°.
mm, it is possible to increase the axial ratio of the long axis and short axis of the magnetic material, making magnetization reversal more likely to occur when a magnetic field is applied, and improving the writing performance of magnetic signals. At the same time, by further increasing the squareness ratio of the hysteresis loop, residual magnetization and coercive force can be further increased, and reproduction output during measurement can be further improved.

Furthermore, according to the sensor having a magnetic film and the manufacturing method thereof of the invention according to claim (4), the depth of the groove is set to 0.2 mm.
As described above, the magnetic coating of the magnetic film can be adjusted so that the -axial shape magnetic anisotropy is approximately along the detection direction of the magnetic signal detection head without affecting the axial ratio of the long axis direction and the short axis direction of the magnetic material. By adding it to the material, it is possible to reliably orient the axis of easy magnetization of the magnetic material in the longitudinal direction of the groove, increase the squareness ratio of the hysteresis loop, increase the residual magnetization and coercive force, and reliably improve the reproduction output during measurement. can.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, in which Fig. 1 is a system explanatory diagram of a sensor having a magnetic film, Fig. 2 is a perspective view of a turbine shaft, and Fig. 3 shows magnetic signals recorded by a pair of magnetic signal recording heads. FIG. 4 is a diagram showing magnetic signals of the magnetic film read by a pair of magnetic signal reading heads when torque is applied. Also, FIG. 5 is a perspective view of the shaft member, FIG. 6 is a perspective view of the plate member, and FIG.
The figure is a characteristic diagram showing the squareness ratio characteristics with respect to the groove spacing of the plate member, Figure 8 is a characteristic diagram showing the relationship of reproduction output characteristics with respect to the distance of the shaft member from the magnetic head, and Figure 9 is a characteristic diagram showing the relationship of reproduction output characteristics with respect to the groove depth. FIG. 3 is a characteristic diagram showing the output characteristics. 1...Sensor 2...Turbine shaft (base material) 3...Magnetic film 4...Magnetic signal detection head 6...Mizobaka 1 person 1...Sensor 2...Turbine shaft (Kio) 3 ... Magnetic film 4 ... Magnetic signal detection head 6 - Groove No. 111J A A 2nd W 4th rI! J 5th W! Figure 6 7Wl! J 0 0,1 0.2 0.3 0.4 Stone portboard 1s 8 blind O spatula)! The stone is square and R cost tψ8 large false 10 0.1 0.2 0.30.4 Groove depth (mm) Fig. 9

Claims (4)

[Claims] (1) In a sensor having a magnetic film in which a magnetic film capable of recording magnetic signals is formed on the surface of a base material, and the magnetic signal recorded on the magnetic film is detected by a magnetic signal detection head, the magnetic film is A sensor having a magnetic film, wherein a plurality of grooves are formed substantially along the detection direction of the magnetic signal detection head. (2) After forming a magnetic film capable of recording magnetic signals on the surface of the base material, a plurality of grooves approximately along the detection direction of the magnetic signal detection head for detecting the magnetic signals recorded on the magnetic film are formed into magnetic layers. A method for manufacturing a sensor having a magnetic film, the method comprising forming a magnetic film on the film. (3) Claim (1) wherein the width of the groove is 0.1 to 1.0 mm.
Or a sensor having a magnetic film according to claim (2) and a method for manufacturing the same. (4) A sensor having a magnetic film according to claim (1) or claim (2), wherein the depth of the groove is 0.2 mm or more, and a method for manufacturing the same.