CN-121986247-A - Position detection system, detection target member, and magnetic detection device

Abstract

The invention provides a miniaturized position sensor with high detection precision. The position detection system is provided with a detection device (110) having a magnetic sensor (112) that detects a change in a magnetic field, and a target member (120) that is disposed so as to face the magnetic sensor (112) at a predetermined interval and is capable of moving relative to the magnetic sensor (112). A target member (120) or a detection device (110) is provided with a magnet film (10) having a thickness of 300 [ mu ] m or less, and the magnet film (10) is provided on the surface of a base material layer (1).

Inventors

• Fujiwara Ryoshimoto
• True guarantee

Assignees

• TDK株式会社

Dates

Publication Date

20260505

Application Date

20241011

Priority Date

20231013

Claims (20)

1. 1. A position detection system, wherein, The position detection system has: a detection device having a magnetic sensor for detecting a change in a magnetic field, and A target member which is disposed so as to face the magnetic sensor at a predetermined interval and is capable of moving relative to the magnetic sensor, The object member or the detection device is provided with a magnet film having a thickness of 10 μm to 300 μm, The magnet film is provided on the surface of the base material layer.
2. 2. The position detection system according to claim 1 wherein, The magnet film has a SmCo 5 film.
3. 3. The position detection system according to claim 2 wherein, A Sm 2 Co 17 film is provided between the magnet film and the substrate layer.
4. 4. The position detection system according to claim 1 wherein, The easy axis of magnetization in the magnet film is oriented in a direction perpendicular to the surface of the base material layer, and the degree of orientation of the easy axis of magnetization is 90% or more.
5. 5. The position detection system according to claim 1 wherein, The surface of the magnet film provided on the target member is magnetized so that different magnetic pole surfaces alternately appear along the relative movement direction.
6. 6. The position detection system according to claim 1 wherein, The surface of the magnet film provided on the target member has a groove pattern in which grooves of a predetermined depth appear at predetermined intervals in the relative movement direction in a predetermined pattern, and is magnetized so that the same magnetic pole surface appears.
7. 7. The position detection system of claim 6 wherein, The substrate layer has a surface provided with a repeating concave-convex pattern corresponding to the groove pattern.
8. 8. The position detection system according to claim 1 wherein, The surface of the magnet film provided on the target member has a groove pattern in which grooves of a predetermined depth appear at predetermined intervals in the relative movement direction in a predetermined pattern, and is magnetized so that different magnetic pole surfaces alternately appear in correspondence with the groove pattern.
9. 9. The position detection system according to claim 1 wherein, The magnet film provided in the target member has a plurality of partial magnet films intermittently arranged at predetermined intervals along the relative movement direction.
10. 10. The position detection system according to claim 9 wherein, The surface of the object member located between the partial magnet films in proximity has a surface composed of a composition substantially free of a part of elements constituting the partial magnet films.
11. 11. The position detection system of claim 10 wherein, The surface of the partial magnet and the surface of the magnetic body are substantially flush planes or curved surfaces.
12. 12. The position detection system according to claim 9 wherein, The surface of the object member located between the partial magnet films in proximity has a suppressing surface of a diffusion suppressing member that suppresses diffusion of a part of the elements constituting the partial magnet films.
13. 13. The position detection system of claim 12 wherein, The surface of the partial magnet film protrudes from the inhibition surface ridge.
14. 14. The position detection system according to claim 1 wherein, The surface of the magnet film provided on the target member has a groove pattern in which grooves of a predetermined depth are formed at predetermined intervals in the relative movement direction and in a predetermined pattern, The predetermined depth of the groove is 0.02 times or more the width of the groove, and the portion of the magnet film located on the top of the protruding portion, which is located between the grooves, is magnetized so that the same magnetic pole surface appears.
15. 15. The position detection system according to any one of claims 1 to 3, wherein, The detection device has a magnetic component composed of a magnetic material, The magnet film is formed on a surface of at least a part of the magnetic member.
16. 16. The position detection system of claim 15 wherein, The object member has a component member having a groove pattern in which grooves of a predetermined depth appear at predetermined intervals in the relative movement direction and in a predetermined pattern on a surface thereof, and the surface of the component member is made of a magnetic material.
17. 17. The position detection system of claim 15 wherein, The detection device is provided with the magnetic member on the other surface of the circuit board opposite to the one surface on which the magnetic sensor is provided.
18. 18. The position detection system of claim 15 wherein, The surface of the magnet film is magnetized in such a manner that different magnetic pole surfaces alternately appear along the relative movement direction.
19. 19. The position detection system of claim 16 wherein, The length of the magnetic member along the relative movement direction has a length that is approximately an integer multiple of 1/2 of the sum of the width of the protruding portion located between adjacent grooves provided in the target member and the width of the recessed portion corresponding to the groove.
20. 20. The position detection system of claim 19 wherein, The magnetic member includes a pair of opposing concave portions that can oppose the concave portions of the target member at predetermined intervals, and a pair of opposing convex portions that are located on both sides of the opposing concave portions along the direction of the relative movement, the magnetic film is provided on a surface of one of the opposing convex portions, and the magnetic sensor is provided on the other opposing convex portion.

Description

Position detection system, detection target member, and magnetic detection device Technical Field The present disclosure relates to a position detection system, a detection target member for the system, and a magnetic detection device. Background For example, as shown in patent document 1 below, a position detection system in which a magnet and a magnetic sensor are combined is known. As a magnet used in a conventional position detection system, a block magnet such as a sintered magnet capable of generating a large magnetic field at low cost is widely used. In recent years, however, miniaturization of various devices has been demanded, and there is a limit to miniaturization of a bulk magnet. On the other hand, although there is a magnet film produced by vacuum film formation or the like, the thickness is extremely thin to several μm or less, and therefore the generated magnetic field is small and is relatively susceptible to noise, and therefore the positional accuracy that can be detected becomes low. Prior art literature Patent literature Patent document 1, utility model registration No. 3189365 Disclosure of Invention Technical problem to be solved by the invention The present disclosure has been made in view of such a practical situation, and an object thereof is to provide a position detection system which is miniaturized and has high detection accuracy, a detection target member used for the system, and a magnetic detection device. Technical scheme for solving technical problems In order to achieve the above object, an aspect of the present disclosure relates to a position detection system including: a detection device having a magnetic sensor for detecting a change in a magnetic field, and A target member which is disposed so as to face the magnetic sensor at a predetermined interval and is capable of moving relative to the magnetic sensor, The object member or the detection device is provided with a magnet film having a thickness of 10 [ mu ] m to 300 [ mu ] m, and the magnet film is provided on the surface of the base material layer. In the position detection system according to the aspect of the present disclosure, since the object member or the detection device is provided with the magnet film having a thickness of 10 μm or more and 300 μm or less, the thickness and size of the position detection system can be reduced. Further, since the magnet film is provided on the surface of the base material layer, the magnet film can be produced by, for example, a molten salt immersion method or a method in which a molten salt immersion method is applied, and the generated magnetic field becomes large and is relatively less susceptible to noise, so that the positional accuracy that can be detected becomes high. The thickness of the magnet film is preferably 15 μm or more, but may be 20 μm or more, 30 μm or more, 50 μm or more, or 50 to 200 μm. Further, in the case where the thickness of the magnet film is too thin, the detection sensitivity tends to be lowered. Preferably, the magnet film has a SmCo 5 film. The SmCo 5 film can be easily formed thin (300 μm or less) and has high magnetization by, for example, reacting the surface of a base material layer (used in terms of a concept including a substrate) made of Co with a reaction liquid containing a Sm source and a molten salt and performing heat treatment. There may also be a Sm 2Co17 film between the magnet film and the substrate layer. The Sm 2Co17 film and the base material layer can function as a part of a yoke of the magnet film. Preferably, the easy axis of magnetization in the magnet film is oriented in a direction perpendicular to the surface of the base material layer, and the degree of orientation of the easy axis is 90% or more. With this configuration, the magnetic properties of the magnet film are improved. The surface of the magnet film provided on the target member may be magnetized so that different magnetic pole surfaces alternately appear along the relative movement direction. With this configuration, when the target member is moved relative to the magnetic sensor, the magnetic sensor can detect a periodic change in the magnetic field generated by the alternately different magnetic pole surfaces, and accurately detect the relative position (including the amount of movement, presence or absence of presence, and the like) of the magnetic sensor relative to the target member based on the periodic change in the magnetic field. The surface of the magnet film provided on the target member may have a groove pattern in which grooves of a predetermined depth are formed at predetermined intervals in the relative movement direction in a predetermined pattern, and may be magnetized so that the same magnetic pole surface is formed. Since the magnetic sensor detects periodic changes in the magnetic field that changes in the position of the slot when the target member moves relative to the magnetic sensor, the relative position (including the amount of