JP2024026033A - Magnetic detection device, magnetic detection unit, magnetic detection system, and method for manufacturing magnetic detection unit - Google Patents

Abstract

SOLUTION: There is provided a magnetic detection device including: a substrate including a hole portion into which a magnet is inserted from a side of one main surface, and a stopper for stopping, from a side of another main surface, the magnet inserted into the hole portion to prevent the magnet from protruding toward the side of the other main surface; and a magnetic sensor mounted at a position corresponding to the hole portion, in the other main surface. The substrate may include a first substrate, and a second substrate bonded to the first substrate from the side of the other main surface. The hole portion may be a first through hole formed in the first substrate. The stopper may include a region, in the second substrate, that closes the first through hole.SELECTED DRAWING: Figure 1

Description

The present invention relates to a magnetic detection device, a magnetic detection unit, a magnetic detection system, and a method for manufacturing a magnetic detection unit.

Patent Document 1 states, ``With the magnetic detecting body 3 consisting of the assembled and integrated package 8, magnet 10, and holder 11 positioned and arranged inside the case 2, the magnetic detecting body 3 is placed in a resin 4. ” (Paragraph 0014).
[Prior art documents]
[Patent document]
[Patent Document 1] Japanese Patent Application Publication No. 2005-337865

In a first aspect of the invention, a magnetic detection device is provided. The magnetic detection device has a hole portion into which a magnet is inserted from one main surface side, and the magnet inserted into the hole portion is locked from the other main surface side and protrudes toward the other main surface side. and a magnetic sensor mounted on the other main surface at a position corresponding to the hole.

In the magnetic detection device described above, the substrate may include a first substrate and a second substrate bonded to the first substrate from the other main surface side. In the magnetic detection device described above, the hole portion may be a first through hole formed in the first substrate. In the magnetic detection device described above, the locking portion may include a region that closes the first through hole in the second substrate.

In any of the above magnetic detection devices, the second substrate may be thinner than the first substrate.

In any of the above magnetic detection devices, a region of the second substrate that closes the first through hole may have a thickness of 0.1 mm or more and 0.6 mm or less.

In any of the above magnetic detection devices, the region of the second substrate that closes the first through hole may include a second through hole through which the magnet cannot pass.

In any of the above magnetic detection devices, the first substrate and the second substrate may be bonded to each other with an adhesive.

In any of the above magnetic detection devices, the first substrate and the second substrate may be adhered to each other with an adhesive sheet.

In any of the magnetic detection devices described above, the outlines forming the outer shapes of the respective main surfaces of the first substrate and the second substrate may be substantially the same.

In any of the magnetic detection devices described above, at least a portion of the second substrate may be formed of a ferromagnetic material. In any of the above magnetic detection devices, the contour forming the outer shape of the main surface of the second substrate may be substantially the same as or smaller than the contour forming the outer shape of the main surface of the first substrate.

In any of the above magnetic detection devices, the locking portion may include an inclined surface that locks the magnet from the other main surface side.

In any of the above magnetic detection devices, the locking portion may include a step that locks the magnet from the other main surface side.

In any of the above magnetic detection devices, the magnetic sensor may be a magnetoresistive element.

In any of the above magnetic detection devices, the magnetic sensor may be a semiconductor magneto resistive (SMR) using indium antimonide (InSb).

In any of the magnetic detection devices described above, the magnetic sensor may be arranged within a range surrounded by an outline forming the outer shape of the magnet when viewed from the one main surface side.

In any of the above magnetic detection devices, the magnetic flux density applied to the magnetic sensor by the magnet may be 400 mT or more.

In a second aspect of the invention, a magnetic detection unit is provided. The magnetic detection unit may include any of the magnetic detection devices described above. The magnetic detection unit may include the magnet. In the magnetic detection unit, at least a part of a surface of the magnet other than a working surface of a magnetic pole may be fixed to a side surface of the hole with an adhesive.

In a third aspect of the invention, a magnetic detection system is provided. The magnetic detection system includes a detected unit and a magnetic detection unit that is provided opposite to the detected unit and detects a change in magnetic flux density due to relative movement of the detected unit, and the magnetic detection unit includes: A magnet provided on a side opposite to the side facing the detected unit, a hole into which the magnet is inserted from the opposite side, and a magnet inserted into the hole is locked from the opposite side. The magnetic sensor includes a substrate having a locking portion for preventing protrusion toward the opposing side, and a magnetic sensor mounted at a position corresponding to the hole on the opposing side of the substrate.

In the magnetic detection system described above, at least a part of a surface of the magnet other than a working surface of a magnetic pole may be fixed to a side surface of the hole with an adhesive.

In any of the above magnetic detection systems, the magnetic flux density applied to the magnetic sensor by the magnet may be 400 mT or more.

In any of the above magnetic detection systems, the detected unit may have concave portions and convex portions alternately arranged along the relative movement direction on the magnetic detection unit side.

In any of the above magnetic detection systems, the detected unit may be a gear.

In any of the magnetic detection systems described above, the hole portion may have an angular outline complementary to an angular outline forming an outer shape of the magnet when viewed from the opposite side. In any of the above magnetic detection systems, when viewed from the opposite side, at least one of the plurality of corners in the angular outline of the hole is the main outline of the angular shape of the hole. It may be concave toward the outside.

In any of the above magnetic detection systems, the substrate may include a first substrate and a second substrate bonded to the first substrate from a side facing the detected unit. In any of the above magnetic detection systems, the hole portion may be a first through hole formed in the first substrate. In any of the above magnetic detection systems, the locking portion may include a region that closes the first through hole in the second substrate. In any of the above magnetic detection systems, the first substrate and the second substrate may be bonded to each other with an adhesive. In any of the above magnetic detection systems, a receiving portion may be formed around the first through hole to receive the adhesive protruding from between the first substrate and the second substrate.

In any of the above magnetic detection systems, the substrate may include a first substrate and a second substrate bonded to the first substrate from a side facing the detected unit. In any of the above magnetic detection systems, the hole portion may be a first through hole formed in the first substrate. In any of the above magnetic detection systems, the locking portion may include a region that closes the first through hole in the second substrate. In any of the above magnetic detection systems, the first substrate and the second substrate may be bonded to each other with an adhesive. In any of the magnetic detection systems described above, when viewed from the opposite side, a protruding range of the adhesive from between the first substrate and the second substrate toward the inside of the first through-hole is equal to It may be within 0.2 mm from the outline of the through hole.

In a fourth aspect of the present invention, a method of manufacturing a magnetic detection unit is provided. A method for manufacturing a magnetic detection system includes a hole portion into which a magnet is inserted from one main surface side, and a hole portion into which a magnet is inserted from the other main surface side, and the magnet inserted into the hole portion is locked from the other main surface side to the other main surface side. mounting a magnetic sensor at a position corresponding to the hole on the other main surface of the substrate, and a locking portion for preventing the substrate from protruding; By inserting the magnet into the hole with a ferromagnetic material or other magnet approaching or in contact with the magnetic sensor on the main surface side of the magnetic sensor, the working surface of the magnetic pole of the magnet is brought into contact with the magnetic sensor. By injecting and curing adhesive between at least a part of the surface of the magnet other than the working surface and the side surface of the hole, the magnet is placed parallel to the hole. and fixing to the side surface.

Note that the above summary of the invention does not list all the features of the invention. Furthermore, subcombinations of these features may also constitute inventions.

FIG. 1 is a schematic side view of the magnetic detection system 10 according to the first embodiment. 2 is a partially enlarged view of the magnetic detection system 10 shown in FIG. 1. FIG. FIG. 1 is a schematic plan view of a magnetic detection device 100 according to a first embodiment. 3 is a flowchart illustrating an example of a method for manufacturing the magnetic detection unit 30 according to the first embodiment. FIG. 2 is a schematic side view of a magnetic detection device 200 according to a second embodiment. FIG. 3 is a schematic side view of a magnetic detection device 300 according to a third embodiment. FIG. 4 is a schematic side view of a magnetic detection device 400 according to a fourth embodiment. FIG. 5 is a schematic side view of a magnetic detection device 500 according to a fifth embodiment. FIG. 6 is a schematic plan view of a magnetic detection device 600 according to a sixth embodiment. 10 is an enlarged view of region 1000 shown in FIG. 9. FIG. 9 is a schematic YZ cross-sectional view of the magnetic detection device 600 taken along line II in FIG. 9. FIG. It is a flowchart which shows an example of the method of forming the 1st through-hole 612 of the 1st board|substrate 611 in the magnetic detection apparatus 600 by 6th Embodiment.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Furthermore, not all combinations of features described in the embodiments are essential to the solution of the invention.

FIG. 1 is a schematic diagram of a magnetic detection system 10 according to a first embodiment. When facing the paper of FIG. 1, the left direction is defined as the Z-axis positive direction, the upward direction is defined as the Y-axis positive direction, and the near side direction is defined as the X-axis positive direction. In addition, in FIG. 1, the magnetic detection unit 30 is shown by a broken line frame.

The magnetic detection system 10 includes a rotating body 20 and a magnetic detection unit 30. The magnetic detection system 10 according to the present embodiment detects a rotational operation of the rotating body 20, such as at least one of the rotation angle, rotation speed, rotation direction, and rotation speed, using the magnetic detection unit 30.

The rotating body 20 is a magnetic body, has a convex portion and/or a concave portion, and rotates around a rotation axis along the X-axis direction. In the rotating body 20, for example, in a cross-sectional shape substantially perpendicular to the rotation axis, the apex of the convex portion is located on a circumference centered on the rotation axis.

The rotating body 20 may have concave portions and convex portions arranged alternately along the relative movement direction on the magnetic detection unit 30 side. The rotating body 20 may be, for example, a gear or a gear-shaped component. FIG. 1 shows an example in which the rotating body 20 has a disk-like shape, and concave portions and convex portions are alternately arranged along the rotational movement direction on the circumference of the disk. Note that the rotating body 20 is an example of a detected unit.

The magnetic detection unit 30 is provided facing the rotating body 20 on the Z-axis negative side of the rotating body 20, and detects changes in magnetic flux density due to relative movement of the rotating body 20. The magnetic detection unit 30 includes a magnet M provided on the opposite side to the side facing the rotating body 20, and a magnetic detection device 100 provided on the side facing the rotating body 20. In other words, in the magnetic detection unit 30, the magnet M and the magnetic detection device 100 are arranged in order from the Z-axis negative side. In addition, in FIG. 1, a part of the magnetic detection device 100 is shown transparently so that the entire side surface of the magnet M can be seen, and the same applies to subsequent figures.

The magnet M generates a predetermined substantially constant magnetic field. The magnet M may be, for example, a permanent magnet containing samarium cobalt, and the residual magnetic flux density of the permanent magnet may be about 800 mT.

The magnet M is arranged such that the working surface of the north or south pole faces the rotating body 20 . The magnet M is arranged close to the rotating body 20 to such an extent that the generated magnetic field can reach the convex portions and/or concave portions of the rotating body 20 .

The magnetic detection device 100 is arranged between the rotating body 20 and the magnet M closer to the rotating body 20 than the magnet M, and faces a convex portion and/or a recessed portion of the rotating body 20. The magnetic detection device 100 detects changes in the magnetic flux density of the magnetic force generated from the magnet M at the convex portions and/or concave portions of the rotating body 20. The magnetic detection device 100 detects the rotational movement of the rotating body 20 based on the magnetic flux density that changes according to the rotation of the rotating body 20.

FIG. 2 is a partially enlarged view of the magnetic detection system 10 shown in FIG. 1, and FIG. 3 is a schematic plan view of the magnetic detection device 100 according to the first embodiment. Note that in FIG. 2, the magnetic detection unit 30 is indicated by a broken line frame, similar to FIG. 1.

The magnetic detection device 100 includes a substrate 110 and a magnetic sensor 120 provided on the side facing the rotating body 20. In this embodiment, the substrate 110 is a non-magnetic plate member. As shown in FIG. 2, the substrate 110 includes a first substrate 111 and a second substrate 114 bonded to the first substrate 111 from the side facing the rotating body 20.

The first substrate 111 and the second substrate 114 in this embodiment may be bonded to each other with an adhesive, for example, an adhesive sheet such as a thin adhesive film. The first substrate 111 and the second substrate 114 may be bonded to each other with a liquid adhesive instead of or in addition to the adhesive sheet. As shown in FIGS. 2 and 3, the outlines forming the respective main surfaces of the first substrate 111 and the second substrate 114 may be substantially the same. Thereby, the first substrate 111 and the second substrate 114 may be bonded to each other over the entire surfaces facing each other.

A first through hole 112 is formed in the first substrate 111 . A magnet M is inserted into the first through hole 112. In FIG. 3, the first through hole 112 and the magnet M, which are not visible from the second substrate 114 side, are indicated by broken lines.

As shown in FIG. 2, for example, at least a part of the surface of the magnet M other than the working surface of the magnetic pole is fixed to the side surface of the first through hole 112 with an adhesive G. Note that during operation of the magnetic detection system 10, the rotating body 20, which is a magnetic body, is always located on the side of the magnetic sensor 120, and the magnet M is in a state of being attracted to the second substrate 114 by its own magnetic force. It is not necessary to fix the magnet M to the side surface of the first through hole 112 with the adhesive G. Note that the magnet M may be fixed to the side surface of the first through hole 112 by other means than the adhesive G. Note that the first through hole 112 is an example of a hole portion into which the magnet M is inserted from one main surface side of the substrate 110.

The second substrate 114 has a locking portion 115. The locking portion 115 locks the magnet M inserted into the first through hole 112 of the first substrate 111 from the side of the first substrate 111 facing the rotating body 20 . Thereby, the locking portion 115 prevents the magnet M from protruding toward the side of the second substrate 114 that faces the rotating body 20 .

In the substrate 110, the combination of the locking portion 115 and the first through hole 112, which is an example of the hole described above, is such that the magnet M is located on the opposite side of the substrate 110 from the side facing the rotating body 20, that is, on the Z-axis negative side. The magnet M allows the magnetic sensor 120 to be positioned closer to the main surface of the substrate 110 on the side facing the rotating body 20, that is, on the positive side of the Z-axis, while the magnet M moves the magnetic sensor 120 closer to the rotating body 20 side. It may also be defined as having a function to prevent pressing.

As an example, the locking portion 115 in this embodiment includes a region of the second substrate 114 that closes the first through hole 112 of the first substrate 111. In other words, the region of the second substrate 114 that closes the first through hole 112 of the first substrate 111 allows the magnet M inserted into the first through hole 112 of the first substrate 111 to face the rotating body 20 of the first substrate 111. It functions as a locking portion 115 that locks from the side that is attached. More specifically, no through hole is formed in the second substrate 114 in a region corresponding to the first through hole 112 of the first substrate 111, and the locking portion 115 of the second substrate 114 is connected to the magnet M. The wall separating the magnetic sensor 120 from the magnetic sensor 120 makes it impossible for the magnetic sensor 120 to be pushed toward the rotating body 20 by the magnet M. In FIGS. 2 and 3, the area included in the locking portion 115 is indicated by a broken line frame. The same applies to subsequent figures.

A magnetic sensor 120 is mounted at the position on the side of the second substrate 114 facing the rotating body 20 . The magnetic sensor 120 is soldered to an electrode (not shown) formed on the second substrate 114, and the electrode is electrically connected to the conductive pattern 116 formed on the second substrate 114 shown in FIG. It is connected to the. Note that the magnetic sensor 120 is connected to a power source (not shown) via the electrodes and the conductor pattern 116, and is supplied with voltage from the power source. Note that, instead of or in addition to the conductive pattern 116, the magnetic sensor 120 may be connected to the power source by other electrical conduction means such as a conductive wire or electrical wiring.

The magnetic sensor 120 has a magnetic sensing part 121. The magnetic sensing unit 121 detects the magnitude and direction of the magnetic field generated by the magnet M. The magnetically sensitive section 121 may include, for example, a magnetoresistive element, a Hall element, a coil, a reed switch, and the like. In FIGS. 2 and 3, the magnetic sensing part 121 is shown in a broken line frame, and is not shown in subsequent figures.

As an example, the magnetic sensing part 121 of the magnetic sensor 120 in this embodiment may be a magnetoresistive element, for example, a semiconductor magnetoresistive element (SMR) using indium antimonide (InSb). Instead of or in addition to the SMR, the magnetic sensing part 121 of the magnetic sensor 120 may include another magnetoresistive element, such as an anisotropic magnetoresistive element (AMR) or a giant magnetoresistive element (GMR). , a tunnel magnetoresistive element (TMR), or the like. In this case, the magnetically sensitive portion 121 includes a plurality of resistors made of InSb and arranged along the moving direction of the convex portion and/or the concave portion of the rotating body 20. The intervals between the plurality of resistors may be determined according to the pitch of the convex portions and/or concave portions of the rotating body 20. Note that the above-mentioned InSb has higher mobility than indium arsenide (InAs), aluminum indium antimony (AlInSb), and the like, and is suitable as a material for SMR.

As understood from the above description, in the magnetic detection unit 30 of this embodiment, the magnet M, the first substrate 111, the second substrate 114, and the magnetic sensor 120 are arranged in this order from the Z-axis negative side. As shown in FIGS. 2 and 3, the magnetic sensor 120 may be arranged within a range surrounded by the outline of the magnet M when viewed from one main surface side of the substrate 110. In this embodiment, the size of the magnet M is required to be greater than or equal to a predetermined size in order to apply a magnetic force greater than or equal to a predetermined magnitude to the magnetic sensor 120; Since there is no restriction on the lower limit of the size of the magnetic sensor 120, the magnetic sensor 120 can be relatively miniaturized according to design requirements. By downsizing the magnetic sensor 120, manufacturing costs can be lowered, and the area occupied by the magnetic sensor 120 on the board 110 is reduced, so the mounting space for other components can be expanded.

In this case, as shown in FIGS. 2 and 3, the magnetically sensitive portion 121 is included within the plane of the magnet M when viewed from one main surface side of the substrate 110. Thereby, the magnetic field of the magnet M can be applied uniformly to the entire magnetic sensing part 121. Note that, when the magnetic sensor 120 is viewed from one main surface side of the substrate 110, at least a part of the outer circumference side excluding the magnetically sensitive portion 121 may not be included in the plane of the magnet M.

The thickness of the first substrate 111 and the second substrate 114 in the Z-axis direction may be substantially constant, or may partially change at any location within the XY plane. In FIG. 2, the main thickness of the first substrate 111 is indicated by T1, and the main thickness of the second substrate 114 is indicated by T2.

The second substrate 114 may be thinner than the first substrate 111. As an example, the thickness of the region of the second substrate 114 that closes the first through hole 112 of the first substrate 111 may be 0.1 mm or more and 0.6 mm or less. It may be difficult to manufacture the second substrate 114 with a thickness less than 0.1 mm in whole or in part. By setting the thickness of the region of the second substrate 114 to 0.6 mm or less and using a permanent magnet containing samarium cobalt with a residual magnetic flux density of about 800 mT as the magnet M, the magnet M can apply an electric current to the magnetic sensor 120. The magnetic flux density can be set to 400 mT or more. Thereby, the output signal amplitude (Vpp) of the magnetic sensor 120 can be set to a predetermined magnitude or more, and therefore, the detection accuracy of magnetic flux density changes by the magnetic sensor 120 can be set to a predetermined threshold value or more. can.

Note that the distance between the rotating body 20 and the magnetic sensor 120, indicated by D1 in FIG. 2, may be about 0.2 mm, for example. Note that this distance may be referred to as an air gap.

As shown in FIG. 3, the four corners of the main surfaces of the first substrate 111 and the second substrate 114, each having a substantially rectangular outer shape, are provided so that the first substrate 111 and the second substrate 114 can be attached to other devices, frames, etc. A hole into which a fixing means is inserted may be formed through both substrates. Note that the outer shape of the substrate 110, for example, the outer shapes of the first substrate 111 and the second substrate 114, is not limited to the above-mentioned substantially rectangular shape, but may be any other shape such as a circular shape or an elliptical shape. As shown in FIG. 3, each of the plurality of conductor patterns 116 formed on the main surface of the second substrate 114 facing the rotating body 20 has one end connected to the magnetic sensor 120 and the other end connected to the substrate 110. The magnetic sensor 120 may be electrically connected to the above-described power source.

Here, as a first comparative example with the magnetic detection unit 30 according to the present embodiment, a magnetic detection device is assumed in which a magnetic sensor is arranged to cover a through hole formed in a substrate, and a magnet is inserted into the through hole. . In the magnetic detection device, the magnetic sensor has a structure in which a magnetoresistive element is packaged in a resin package, and a lead frame is exposed in the central region of the back surface of the resin package. The lead frame of the magnetic sensor is soldered to electrodes on the substrate at several locations on the outer edge of the lead frame. A magnet is fixed with adhesive to a region of the main surface of the magnetic sensor on the substrate side that closes the through hole of the substrate. That is, the central region of the lead frame exposed on the main surface of the magnetic sensor on the substrate side is covered with a magnet. The board is fixed to another device, a frame, or the like.

According to such a first comparative example, when a magnetic detection device is used with a magnetic sensor facing a detected unit that moves relative to a fixed substrate, the magnet that tries to attract the detected unit Due to the magnetic force, a force is applied to the magnetic sensor to push it toward the detected unit. As a result, the portion fixing the magnetic sensor to the substrate may be torn, and the magnetic sensor may be struck onto the detected unit so as to be sandwiched between the magnet and the detected unit.

According to such a first comparative example, since the central region of the lead frame exposed on the main surface on the substrate side of the magnetic sensor is covered with a magnet, the central region has a high thermal conductivity such as an electrode. The heat dissipation of the magnetic sensor is lower than when the magnetic sensor is covered with a material having a high height.

As a second comparative example with the magnetic detection device 100 according to the present embodiment, a magnetic sensor is arranged on one main surface of a substrate in which no through hole is formed, and a magnet is placed at a corresponding position on the other main surface of the substrate. Assume a magnetic detection device with a . In the magnetic detection device, the magnetic sensor is soldered to electrodes on the substrate at several locations. The magnet is fixed onto the substrate with adhesive. The board is fixed to another device, a frame, or the like.

According to such a second comparative example, the thickness of the substrate is set to about 1.4 mm in order to ensure strength. That is, the distance between the magnetic sensor and the magnet is about 1.4 mm. In order to apply a magnetic flux density of 400 mT or more from the magnet to the magnetic sensor through such a distance, it is necessary to use a neodymium magnet, which has the highest magnetic force among permanent magnets, or a large samarium cobalt magnet. It is necessary to

However, neodymium magnets have poorer temperature characteristics than samarium cobalt magnets, and the higher the temperature of a heating element in the surrounding environment of the magnetic detection device, such as the motor of a machine tool to which the magnetic detection device is attached, the weaker the magnetic field becomes. The signal amplitude (Vpp) becomes smaller. As a result, for example, the angular error due to the air gap fluctuation between the magnetic detection device and the detected unit due to the uneven shape of the non-detecting surface of the detected unit may become large, and it becomes difficult to correct the error, and the magnetic flux The detection accuracy of density changes may be reduced.

On the other hand, when using a large samarium cobalt magnet, it is necessary to make the samarium cobalt magnet considerably large in order to apply a magnetic flux density of 400 mT or more to the magnetic sensor through a distance of about 1.4 mm. It is difficult to mount a magnetic detection device equipped with such a large samarium cobalt magnet in an encoder that is limited in size.

On the other hand, according to the magnetic detection device 100 according to the present embodiment, the first through hole 112 into which the magnet M is inserted from one main surface side, and the magnet M inserted into the first through hole 112 from the other side. A substrate 110 is provided that has a locking portion 115 that locks from the main surface side and prevents it from protruding toward the other main surface. The magnetic detection device 100 according to the present embodiment includes a magnetic sensor 120 mounted at a position corresponding to the first through hole 112 on the other main surface of the substrate 110.

According to the magnetic detection device 100 having such a configuration, the distance between the magnet M and the magnetic sensor 120 is made shorter than the main thickness of the substrate 110, for example, about 1.4 mm, for example, about 0.2 mm. can do. By making the distance between the magnet M and the magnetic sensor 120 shorter than a predetermined length, even if a samarium cobalt magnet of a size applicable to the encoder is used as the magnet M, the magnetic The magnetic flux density applied to the sensor 120 can be 400 mT or more. As a result, the output signal amplitude (Vpp) of the magnetic sensor 120 can be set to a predetermined magnitude or more, and as a result, the above-mentioned angular error is suppressed, and the detection accuracy of magnetic flux density changes by the magnetic sensor 120 is improved. It can be greater than or equal to a predetermined threshold.

On the other hand, according to the magnetic detection device 100, by preventing the magnet M from protruding toward the side of the substrate 110 that faces the detected unit, the magnetic sensor 120 is prevented from being pushed toward the detected unit. This can prevent the magnetic sensor 120 from hitting the detected unit.

Further, in the magnetic detection device 100 according to the present embodiment, the substrate 110 may include a first substrate 111 and a second substrate 114 bonded to the first substrate 111 from the side facing the rotating body 20. A region of the second substrate 114 that closes the first through hole 112 of the first substrate 111 may function as a locking portion 115. In this case, an electrode is provided in the region on the side of the second substrate 114 facing the rotating body 20, and the lead frame of the magnetic sensor 120 is soldered to the electrode. In this case, the magnetic sensor 120 may also be arranged within a range surrounded by the outline of the magnet M when viewed from one main surface side of the substrate 110.

According to the magnetic detection device 100 having such a configuration, the heat dissipation of the magnetic sensor 120 can be improved compared to the above-described first comparative example. According to the magnetic detection device 100 having such a configuration, since there is no restriction on the lower limit of the size of the magnetic sensor 120, the magnetic sensor 120 can be downsized according to design requirements, and the magnetic sensor 120 can be downsized. By doing so, manufacturing costs can be lowered, and the area occupied by the magnetic sensor 120 on the board 110 can be reduced, thereby expanding the mounting space for other components.

In order to verify that the magnetic detection device 100 according to the present embodiment can achieve the above effect, the inventors of the present application discovered that the magnetic detection device 100 according to the present embodiment has substantially the same outline forming the outer shape of each main surface and is bonded to each other using an adhesive sheet. A magnetic detection device 100 including a first substrate 111 and a second substrate 114 was prepared, and a test was conducted in which stress was applied to the magnet M inserted into the first through hole 112 of the first substrate 111 using a push-pull gauge. Ta. The inventors of the present application also conducted a similar test on the magnetic detection device according to the first comparative example described above.

As a result of the test, in the magnetic detection device according to the first comparative example, the solder part that fixes the magnetic sensor to the board was peeled off and destroyed when about 10N was applied, and in the magnetic detection device 100 according to the present embodiment, when about 30N was applied, the solder part was peeled off and destroyed. It was confirmed that the first substrate 111 and the second substrate 114 did not separate even when the voltage was applied.

FIG. 4 is a flowchart illustrating an example of a method for manufacturing the magnetic detection unit 30 according to the first embodiment. The flow of FIG. 4 starts by preparing a substrate 110 consisting of a first substrate 111 and a second substrate 114, which have substantially the same contours forming the outer shape of their respective main surfaces and are bonded to each other with an adhesive sheet. Good too.

The magnetic sensor 120 is mounted on the substrate 110 at a position corresponding to the first through hole 112 on the main surface of the substrate 110 on the Z-axis positive side (step S101). By inserting the magnet M into the first through hole 112 with the ferromagnetic material or other magnet M-1 approaching or in contact with the magnetic sensor 120 on the Z-axis positive side of the substrate 110, the magnetic pole of the magnet M is changed. The active surface of the magnetic sensor 120 is made parallel to the magnetic sensor 120 (step S102). Note that in step S102, a ferromagnetic material such as iron may be used instead of the other magnet M-1. Furthermore, instead of bringing the other magnet M-1 into contact with the magnetic sensor 120, the other magnet M-1 may be brought close to the magnetic sensor 120.

The magnet M is fixed to the side surface of the first through hole 112 by injecting and curing the adhesive G between at least a part of the surface of the magnet M other than the active surface and the side surface of the first through hole 112. (Step S103), thereby completing the magnetic detection unit 30, and the flow ends. Note that in step S103, for example, after the adhesive G has hardened and the magnet M has been fixed to the side surface of the first through hole 112, the other magnet M-1 may be removed.

In the magnetic detection device 100 according to the first embodiment described above, the first substrate 111 having the first through hole 112 and the rotating body 20 side of the first substrate 111 have the above-described hole portion and locking portion. The substrate 110 has been described in combination with a thin second substrate 114 to be bonded. Furthermore, the first through hole 112 and the second substrate 114 have been described as having substantially the same outline forming the outer shape of their respective main surfaces. The structure of the substrate having the hole portion and the locking portion described above is not limited to these. For example, the two substrates to be bonded together may have different outlines forming the respective main surfaces. The substrate having the hole and the locking portion described above may be a single substrate. The above-mentioned hole may be a through hole whose size changes continuously or stepwise, as long as the magnet M can be inserted into the board from the negative side of the Z-axis, or may be a recess or hole that does not penetrate the board. It may be a dent.

FIG. 5 is a schematic side view of the magnetic detection device 200 according to the second embodiment. The magnetic detection device 200 differs from the magnetic detection device 100 according to the first embodiment in that it includes a substrate 210 having a second substrate 214 instead of the substrate 110 having the second substrate 114 . The other configurations of the magnetic detection device 200 may be the same as the corresponding configurations of the magnetic detection device 100 according to the first embodiment, and the reference numbers used in the corresponding configurations of the first embodiment will be used to duplicate the description. omitted. Furthermore, in FIG. 5, magnets M that are not included in the magnetic detection device 200 are indicated by broken lines. The same applies to the descriptions of the subsequent embodiments.

The substrate 210 includes a first substrate 111 and a second substrate 214 bonded to the first substrate 111. The locking portion 215 in the second substrate 214 includes a region of the second substrate 114 that closes the first through hole 112 of the first substrate 111, and this region includes a second through hole 217 through which the magnet M cannot pass. include. The magnetic detection device 200 of the second embodiment including the substrate 210 having such a structure also provides the same effects as the magnetic detection device 100 of the first embodiment.

FIG. 6 is a schematic side view of a magnetic detection device 300 according to the third embodiment. The magnetic detection device 300 differs from the magnetic detection device 100 according to the first embodiment in that it includes a substrate 310 having a second substrate 314 instead of the substrate 110 having the second substrate 114.

The substrate 310 includes a first substrate 111 and a second substrate 314 bonded to the first substrate 111. The second substrate 314 is at least partially formed of a ferromagnetic material, and the contour of the main surface of the second substrate 314 is substantially the same as the contour of the main surface of the first substrate 111. or even smaller. The second substrate 314 is made of, for example, a ferromagnetic material containing a material with high magnetic permeability, such as iron, and may have an insulated surface so as not to be electrically connected to the magnetic sensor 120. As shown in FIG. 6, as an example, the contour of the second substrate 314 is smaller than the contour of the first substrate 111, and the locking portion 315 of the second substrate 314 is connected to the first through hole 111 of the first substrate 111. The second substrate 314 itself may be large enough to close the first through hole 112 as long as it includes a region that closes the first through hole 112 . The magnetic detection device 300 of the third embodiment including the substrate 310 having such a structure also provides the same effects as the magnetic detection device 100 of the first embodiment. In the magnetic detection device 300 of the third embodiment, the amount of change in the magnetic flux density of the magnetic force generated from the magnet M is further increased due to the magnetism collecting effect of the second substrate 314 formed of a ferromagnetic material containing a material with high magnetic permeability. Therefore, the output signal amplitude (Vpp) of the magnetic sensor 120 can be further increased compared to the magnetic detection device 100 of the first embodiment.

FIG. 7 is a schematic side view of a magnetic detection device 400 according to the fourth embodiment. The magnetic detection device 400 differs from the magnetic detection device 100 according to the first embodiment in that it includes a single substrate 410 instead of the substrate 110 having the second substrate 114.

The substrate 410 includes a through-hole 412 into which the magnet M is inserted from the negative side of the Z-axis of the substrate 410, and a locking portion 415 that locks the magnet M inserted into the through-hole 412 from the positive side of the Z-axis. The locking portion 415 includes an inclined surface 418 that locks the magnet M from the positive side of the Z-axis. The combination of the through hole 412 and the locking portion 415 including the inclined surface 418 may be defined as a through hole whose size changes continuously. The magnet M in this embodiment has a shape complementary to the inclined surface 418 of the locking portion 415. That is, the magnet M in this embodiment has a tapered cross-sectional shape in the YZ plane at least in the portion inserted into the inside of the substrate 410. The magnetic detection device 400 of the fourth embodiment including the substrate 410 having such a structure also provides the same effects as the magnetic detection device 100 of the first embodiment. Furthermore, in the magnetic detection device 400 of the fourth embodiment, the bonding area between the substrate 410 and the magnet M can be expanded compared to the magnetic detection device 100 of the first embodiment. Note that the magnet M does not have to have a shape complementary to the inclined surface 418 of the locking part 415, and may have a rectangular parallelepiped shape, for example, as in other embodiments. Even in this case, since the locking portion 415 of the substrate 410 includes the inclined surface 418, the bonding area between the substrate 410 and the magnet M can be expanded compared to the magnetic detection device 100 of the first embodiment.

FIG. 8 is a schematic side view of a magnetic detection device 500 according to the fifth embodiment. The magnetic detection device 500 differs from the magnetic detection device 100 according to the first embodiment in that it includes a single substrate 510 instead of the substrate 110 having the second substrate 114.

The substrate 510 includes a through-hole 512 into which the magnet M is inserted from the negative side of the Z-axis of the substrate 510, and a locking portion 515 that locks the magnet M inserted into the through-hole 512 from the positive side of the Z-axis. The locking portion 515 includes a step 519 that locks the magnet M from the positive side of the Z-axis. The combination of the through hole 512 and the locking portion 515 including the step 519 may be defined as a through hole whose size changes stepwise. The magnetic detection device 500 of the fifth embodiment including the substrate 510 having such a structure also provides the same effects as the magnetic detection device 100 of the first embodiment.

FIG. 9 is a schematic plan view of a magnetic detection device 600 according to the sixth embodiment. The magnetic detection device 600 according to the sixth embodiment differs from the magnetic detection device 100 according to the first embodiment in that it includes a substrate 610 having a first substrate 611 and a second substrate 114 instead of the substrate 110. The first substrate 611 and the second substrate 114 in this embodiment are bonded to each other with a liquid or film adhesive.

The first substrate 611 of this embodiment differs from the first substrate 111 of the first embodiment in that a first through hole 612 is formed instead of the first through hole 112. A magnet M is inserted into the first through hole 612. In FIG. 9, the magnetic sensor 120 and the conductive pattern 116, which are not visible from the first substrate 611 side, are indicated by broken lines.

As shown in FIG. 9, the first through hole 612 may have an angular outline complementary to an angular outline forming the outer shape of the magnet M when viewed from one main surface side. When viewed from one main surface side, at least one of the plurality of corners 613 in the angular outline of the first through hole 612 is located on the outside of the angular main outline of the first through hole 612. It may be concave toward the surface. In the illustrated example, the first through hole 612 has a substantially rectangular contour when viewed from one main surface side, and the four corners 613 of this contour are the approximately rectangular shape of the first through hole 612. It is concave outward from the main contour. Note that the above-mentioned term angular shape may refer to a substantially square shape, a substantially rectangular shape, and the like.

Each corner 613 may be an example of a receiving part formed around the first through hole 612. The receiving portion receives adhesive that protrudes from between the first substrate 611 and the second substrate 114.

FIG. 10 is an enlarged view of region 1000 shown in FIG. In FIG. 10, the adhesive protruding from between the first substrate 611 and the second substrate 114 is indicated by a shaded region R. In FIG. 10, the illustration of the magnet M, the magnetic sensor 120, and the conductive pattern 116 is omitted simply for clarity of explanation, and the second substrate 114 is exposed inside the first through hole 612 of the first substrate 611. Indicates the condition.

As shown in FIG. 10, when viewed from one main surface side, the adhesive protrusion range D from between the first substrate 611 and the second substrate 114 toward the inside of the first through hole 612 is predetermined. For example, it may be within 0.2 mm from the outline of the first through hole 612.

FIG. 11 is a schematic YZ cross-sectional view of the magnetic detection device 600 taken along line II in FIG. In FIG. 11, as in FIG. 2, the main thickness of the first substrate 611 is indicated by T1, and the main thickness of the second substrate 114 is indicated by T2. In FIG. 11, the width of the first through hole 612 in the Y-axis direction is further indicated by D2. In this embodiment, as an example, T1 may be 1.4 mm, T2 may be 0.2 mm, and D2 may be 4.6 mm.

FIG. 12 is a flowchart illustrating an example of a method for forming the first through hole 612 of the first substrate 611 in the magnetic detection device 600 according to the sixth embodiment. The flow in FIG. 12 may be started by preparing the first substrate 611 in which the first through hole 612 is not formed.

Using a first cutting tool such as a router, the magnetic sensor 120 is mounted on the central region of the main surface on the Z-axis negative side of the first substrate 611, that is, on the second substrate 114 that is bonded to the first substrate 611. A through hole 615 is formed at a position corresponding to the position (step S201). The through hole 615 has a substantially rectangular profile complementary to the substantially rectangular profile forming the outer shape of the magnet M when viewed from one main surface side of the first substrate 611 . However, due to the specifications of the router, it may be difficult to finish each corner of the through hole 615 at right angles, and when inserting the magnet M into the through hole 615, the corners of the magnet M may interfere with each other. There is a possibility that it cannot be done. Therefore, a second cutting tool having a smaller cutting edge than the first cutting tool is used to round the four corners of the through hole 615 (step S202), thereby forming four corners 613. The first through hole 612 is completed and the flow ends. The first substrate 611 can prevent the magnet M from interfering with the first through hole 612 having four corners 613.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the range described in the above embodiments. It will be apparent to those skilled in the art that various changes or improvements can be made to the embodiments described above. It is clear from the claims that such modifications or improvements may be included within the technical scope of the present invention.

The order of execution of each process, such as the operation, procedure, step, and stage in the apparatus, system, program, and method shown in the claims, specification, and drawings, is specifically defined as "before" or "before". It should be noted that they can be implemented in any order unless the output of the previous process is used in the subsequent process. Even if the claims, specifications, and operational flows in the drawings are explained using "first," "next," etc. for convenience, this does not mean that it is essential to carry out the operations in this order. It's not a thing.

10 Magnetic detection system 20 Rotating body 30 Magnetic detection unit 100, 200, 300, 400, 500 Magnetic detection device 110, 210, 310, 410, 510, 610 Substrate 111, 611 First substrate 112, 612 First through hole 114, 214, 314 Second board 115, 215, 315, 415, 515 Locking part 116 Conductor pattern 120 Magnetic sensor 121 Magnetic sensing part 217 Second through hole 412, 512 Through hole 418 Slanted surface 519 Step G Adhesive M Magnet 613 Corner Part 615 Through hole

Claims (25)

A hole portion into which a magnet is inserted from one main surface side and the magnet inserted into the hole portion is locked from the other main surface side to prevent it from protruding toward the other main surface side. a board having a locking portion;
and a magnetic sensor mounted at a position corresponding to the hole on the other main surface. The substrate includes a first substrate and a second substrate bonded to the first substrate from the other main surface side,
The hole is a first through hole formed in the first substrate,
The locking portion includes a region that closes the first through hole in the second substrate.
The magnetic detection device according to claim 1. the second substrate is thinner than the first substrate;
The magnetic detection device according to claim 2. The thickness of the region of the second substrate that closes the first through hole is 0.1 mm or more and 0.6 mm or less,
The magnetic detection device according to claim 3. A region of the second substrate that closes the first through hole includes a second through hole through which the magnet cannot pass.
The magnetic detection device according to claim 2. the first substrate and the second substrate are bonded to each other with an adhesive;
The magnetic detection device according to claim 2. the first substrate and the second substrate are adhered to each other with an adhesive sheet;
The magnetic detection device according to claim 6. The contours forming the respective main surfaces of the first substrate and the second substrate are substantially the same;
The magnetic detection device according to claim 2. The second substrate is at least partially formed of a ferromagnetic material,
The contour forming the outer shape of the main surface of the second substrate is substantially the same as or smaller than the contour forming the outer shape of the main surface of the first substrate.
The magnetic detection device according to claim 2. The locking portion includes an inclined surface that locks the magnet from the other main surface side.
The magnetic detection device according to claim 1. The locking portion includes a step that locks the magnet from the other main surface side.
The magnetic detection device according to claim 1. The magnetic sensor is a magnetoresistive element,
The magnetic detection device according to claim 1. The magnetic sensor is a semiconductor magneto resistive (SMR) using indium antimonide (InSb).
The magnetic detection device according to claim 12. The magnetic sensor is arranged within a range surrounded by an outline forming the outer shape of the magnet when viewed from the one main surface side.
The magnetic detection device according to claim 1. The magnetic flux density applied to the magnetic sensor by the magnet is 400 mT or more,
The magnetic detection device according to claim 1. The magnetic detection device according to claim 1;
and the magnet;
At least a part of the surface of the magnet other than the working surface of the magnetic pole is fixed to the side surface of the hole with an adhesive.
Magnetic detection unit. A detected unit,
and a magnetic detection unit that is provided opposite to the detected unit and detects a change in magnetic flux density due to relative movement of the detected unit,
The magnetic detection unit includes:
a magnet provided on the opposite side of the side facing the detected unit;
a hole portion into which the magnet is inserted from the opposite side; and a locking portion for locking the magnet inserted into the hole portion from the opposing side and preventing it from protruding toward the opposing side. a substrate having;
a magnetic sensor mounted at a position corresponding to the hole on the opposing side of the substrate;
Magnetic detection system. At least a part of the surface of the magnet other than the working surface of the magnetic pole is fixed to the side surface of the hole with an adhesive.
The magnetic detection system according to claim 17. The magnetic flux density applied to the magnetic sensor by the magnet is 400 mT or more,
The magnetic detection system according to claim 17. The detected unit has concave portions and convex portions alternately arranged along the relative movement direction on the magnetic detection unit side.
The magnetic detection system according to claim 17. the detected unit is a gear;
The magnetic detection system according to claim 20. The hole has an angular outline that is complementary to an angular outline forming the outer shape of the magnet when viewed from the opposite side,
When viewed from the opposite side, at least one of the plurality of corners in the angular outline of the hole is recessed outward from the main outline of the angular shape of the hole. ,
The magnetic detection system according to claim 17. The substrate includes a first substrate and a second substrate bonded to the first substrate from a side facing the detected unit,
The hole is a first through hole formed in the first substrate,
The locking portion includes a region that closes the first through hole in the second substrate,
the first substrate and the second substrate are bonded to each other with an adhesive;
A receiving portion is formed around the first through hole to receive the adhesive protruding from between the first substrate and the second substrate.
The magnetic detection system according to claim 17. The substrate includes a first substrate and a second substrate bonded to the first substrate from a side facing the detected unit,
The hole is a first through hole formed in the first substrate,
The locking portion includes a region that closes the first through hole in the second substrate,
the first substrate and the second substrate are bonded to each other with an adhesive;
When viewed from the opposite side, the extent of the adhesive protruding from between the first substrate and the second substrate toward the inside of the first through hole is within 0.2 mm from the outline of the first through hole. is,
The magnetic detection system according to claim 17. A hole portion into which a magnet is inserted from one main surface side and the magnet inserted into the hole portion is locked from the other main surface side to prevent it from protruding toward the other main surface side. mounting a magnetic sensor at a position corresponding to the hole on the other main surface of the substrate, with respect to a substrate having a locking portion;
By inserting the magnet into the hole with a ferromagnetic material or other magnet approaching or in contact with the magnetic sensor on the other main surface side of the substrate, the working surface of the magnetic pole of the magnet is to be parallel to the magnetic sensor;
fixing the magnet to the side surface of the hole by injecting and curing adhesive between at least a part of the surface of the magnet other than the working surface and the side surface of the hole; A method of manufacturing a magnetic detection unit.

Images