Foreign matter detection unit and foreign matter detection device comprising same

Abstract

[Problem] To provide a foreign matter detection unit with which it is possible to detect a minuscule magnetic body contained in a fluid. [Solution] This foreign matter detection unit 20 comprises: an internal flow path 60 having an upstream part 61, a downstream part 62, and a throttle part 63 that is positioned between the upstream part 61 and the downstream part 62 and that has a smaller cross-sectional area than the upstream part 61 and the downstream part 62; and a magnetic sensor S1 that is disposed so as to cover the throttle part 63 of the internal flow path 60 and that detects a magnetic body contained in a fluid flowing through the throttle part 63 of the internal flow path 60. It is thereby possible to detect the minscule magnetic body contained in the fluid with high sensitivity because the distance between the magnetic body and the magnetic sensor S1 is reduced.

Description

Foreign matter detection unit and foreign matter detection device including the same

[0001] The present disclosure relates to a foreign matter detection unit and a foreign matter detection device including the same, and particularly relates to a foreign matter detection unit for detecting magnetic substances contained in a fluid and a foreign matter detection device including the same.

[0002] Patent Document 1 discloses an inspection device that detects a magnetic substance contained in an inspection object by arranging a magnetic sensor outside a pipe through which the inspection object flows.

[0003] Japanese Unexamined Patent Application Publication No. 2021-167768

[0004] However, when the distance between the magnetic substance contained in the inspection object and the magnetic sensor is large, it is difficult to detect minute magnetic substances.

[0005] The present disclosure describes a foreign matter detection unit capable of detecting minute magnetic substances contained in a fluid and a foreign matter detection device including the same.

[0006] According to one aspect of the present disclosure, the foreign matter detection unit includes: an internal flow path positioned between an upstream portion, a downstream portion, and the upstream portion and the downstream portion, the internal flow path having a constricted portion with a smaller cross-sectional area than the upstream portion and the downstream portion; and a magnetic sensor arranged to cover the constricted portion of the internal flow path and configured to detect a magnetic substance contained in a fluid flowing through the constricted portion of the internal flow path.

[0007] According to one aspect of the present disclosure, the foreign matter detection device includes: the above foreign matter detection unit; a first external flow path detachably connected to an upstream portion of the internal flow path; and a second external flow path detachably connected to a downstream portion of the internal flow path.

[0008] According to the present disclosure, it is possible to provide a foreign matter detection unit capable of detecting minute magnetic substances contained in a fluid and a foreign matter detection device including the same.

[0009] Figure 1 is a schematic perspective view showing the external appearance of a foreign object detection device 10 according to one embodiment of the technology of this disclosure. Figure 2(a) is a schematic perspective view showing the foreign object detection device 10 with the shield part 31 removed, and Figure 2(b) is a schematic perspective view showing the foreign object detection device 10 with the shield parts 31 and 32 removed. Figure 3 is a schematic plan view showing the structure of the internal flow path 60. Figure 4 is an enlarged view of the constricted portion 63 of the internal flow path 60 and its surroundings. Figure 5 is a schematic cross-sectional view of the constricted portion 63 of the internal flow path 60 and its surroundings viewed from the X direction. Figure 6 is a schematic perspective view showing the external appearance of the magnetic sensor S1. Figure 7 is a schematic perspective view showing the magnetic sensor S1 with the molded resin 80, magnetic collector 110, and bobbin 140 removed. Figure 8 is a schematic exploded perspective view showing the magnetic sensor S1 with the molded resin 80, magnetic collector 110, and bobbin 140 removed. Figure 9 is a schematic plan view of the sensor chip 100. Figure 10 is a schematic cross-sectional view along the line A-A in Figure 9. Figure 11 is a schematic diagram showing magnetic field lines 91 generated from foreign matter 90.

[0010] The embodiments of the technology described herein will be described in detail below with reference to the attached drawings.

[0011] Figure 1 is a schematic perspective view showing the external appearance of a foreign object detection device 10 according to one embodiment of the technology described herein.

[0012] As shown in Figure 1, the foreign object detection device 10 according to this embodiment comprises a foreign object detection unit 20, external flow channels 41 and 42 detachably connected to the foreign object detection unit 20, and a magnetization unit 50 arranged to cover the external flow channel 41. The external flow channel 41 is the upstream flow channel, and the external flow channel 42 is the downstream flow channel. The fluid to be inspected flows in from the external flow channel 41, passes through the foreign object detection unit 20, and flows out to the external flow channel 42. The fluid to be inspected can be a liquid or a gas. As an example, the fluid to be inspected may be a conductive paste containing copper.

[0013] The foreign object detection unit 20 is a unit for detecting magnetic materials contained in a fluid, and is covered with a substantially cylindrical magnetic shield 30 to prevent it from being affected by external magnetic fields. In the example shown in Figure 1, the magnetic shield 30 is composed of a combination of two shield parts 31 and 32.

[0014] Figure 2(a) is a schematic perspective view showing the foreign object detection device 10 with the shield part 31 removed, and Figure 2(b) is a schematic perspective view showing the foreign object detection device 10 with the shield parts 31 and 32 removed.

[0015] As shown in Figures 2(a) and 2(b), the foreign object detection unit 20 comprises flow path blocks 21 and 22 covered with a magnetic shield 30, and a sensor unit 23 positioned between the flow path block 21 and the flow path block 22. The flow path block 21 is a block body that constitutes the upstream part of the internal flow path, and the external flow path 41 can be attached and detached by screwing it in or the like. The flow path block 22 is a block body that constitutes the downstream part of the internal flow path, and the external flow path 42 can be attached and detached by screwing it in or the like. In the example shown in Figures 2(a) and 2(b), the magnetic shield 30 covers the entire circumference of the flow path blocks 21 and 22 and the sensor unit 23, but the magnetic shield 30 may selectively cover the sensor unit 23 without covering part or all of the flow path blocks 21 and 22.

[0016] Figure 3 is a schematic plan view showing the structure of the internal flow path 60.

[0017] As shown in Figure 3, the internal flow path 60 through which the fluid to be inspected flows has an upstream section 61 formed by a flow path block 21, a downstream section 62 formed by a flow path block 22, and a constricted section 63 located between the upstream section 61 and the downstream section 62, with a smaller cross-sectional area than the upstream section 61 and the downstream section 62. The magnetic sensors S1 and S2 included in the sensor unit 23 are positioned to cover the constricted section 63 of the internal flow path 60. In other words, the cross-sectional area of ​​the internal flow path 60 is locally reduced in the region where the magnetic sensors S1 and S2 are positioned. As a result, magnetic materials contained in the fluid flowing through the constricted section 63 of the internal flow path 60 are detected by the magnetic sensors S1 and S2.

[0018] Figure 4 is an enlarged view of the constricted portion 63 of the internal flow path 60 and its surrounding area.

[0019] As shown in Figure 4, the throttling portion 63 of the internal flow path 60 is sandwiched from the Z direction by magnetic sensors S1 and S2. In the example shown in Figure 4, the orientations of magnetic sensors S1 and S2 in the X direction are reversed by 180°. The symbol P in Figure 4 represents the sensitivity position of magnetic sensors S1 and S2 in the X direction. Thus, the sensitivity positions P of magnetic sensors S1 and S2 in the X direction may coincide with each other. The X direction is the flow direction of the internal flow path 60.

[0020] Figure 5 is a substantially cross-sectional view of the constricted portion 63 of the internal flow path 60 and its surrounding area, as seen from the X direction.

[0021] As shown in Figure 5, the cross-sectional shape of the constricted portion 63 of the internal flow path 60 is not circular, but rather has a shape in which the diameter in the Z direction is smaller than the diameter in the Y direction. The magnetic sensors S1 and S2 are positioned so as to sandwich the constricted portion 63 of the internal flow path 60 from the Z direction. This shortens the distance in the Z direction between the fluid flowing through the constricted portion 63 of the internal flow path 60 and the magnetic sensors S1 and S2.

[0022] Figure 6 is a schematic perspective view showing the external appearance of magnetic sensor S1. Magnetic sensor S2 has the same structure as magnetic sensor S1.

[0023] As shown in Figure 6, the magnetic sensor S1 comprises a substrate 70, a sensor chip 100 mounted on the surface 71 of the substrate 70, magnetic collectors 110, 120, a dummy chip 130, a bobbin 140, and a molded resin 80. The magnetic collectors 110 and 120 are blocks made of a high-permeability material such as a ferrite sintered body, and play the role of concentrating a magnetic field on the magnetosensitive element provided on the sensor chip 100. The dummy chip 130 is positioned on the back side of the sensor chip 100 and plays the role of mechanically reinforcing the sensor chip 100. The bobbin 140 is provided so as to cover the magnetic collector 110, and a compensation coil C1 is wound around it. U-shaped terminal fittings 141 and 142 are fixed to the bobbin 140, with one end of the compensation coil C1 being wound around one protrusion of terminal fitting 141 and the other end of the compensation coil C1 being wound around one protrusion of terminal fitting 142.

[0024] Figures 7 and 8 are a simplified perspective view and a simplified exploded perspective view, respectively, showing the magnetic sensor S1 with the molded resin 80, magnetic collector 110, and bobbin 140 removed.

[0025] As shown in Figures 7 and 8, electrode patterns 72 to 79 are provided on the surface 71 of the substrate 70. Electrode patterns 72 and 73 are connected to the other protruding parts of terminal fittings 141 and 142, respectively. Electrode patterns 74 to 79 are connected to the power terminals and signal terminals of the bridge circuit including the magnetic sensor element integrated on the sensor chip 100, and to the compensation coil integrated on the sensor chip 100.

[0026] As shown in Figure 8, the sensor chip 100 has an element formation surface 101 and a back surface 102 that constitute the YZ plane and are located on opposite sides of each other, side surfaces 103 and 104 that constitute the XZ plane and are located on opposite sides of each other, and side surfaces 105 and 106 that constitute the XY plane and are located on opposite sides of each other, and is mounted on the substrate 70 such that side surface 105 faces the surface 71 of the substrate 70. A magnetic sensor element and magnetic layers M1 to M3, which will be described later, are formed on the element formation surface 101 of the sensor chip 100.

[0027] As shown in Figure 8, the magnetic collector 120 includes side plate portions 121 and 122 extending in the X direction, a connecting portion 123 connected to the end of the side plate portion 121 in the +X direction and the end of the side plate portion 122 in the +X direction, an overhang portion 124 connected to the end of the side plate portion 121 in the -X direction, and an overhang portion 125 connected to the end of the side plate portion 122 in the -X direction.

[0028] Then, the sensor chip 100 and the dummy chip 130 are placed in the region enclosed by the side plate portions 121, 122, connecting portion 123, and overhang portions 124, 125 that constitute the magnetic collector 120. When the sensor chip 100 is placed in the region enclosed by the magnetic collector 120, the side surface 103 of the sensor chip 100 is covered by the side plate portion 121 of the magnetic collector 120, the side surface 104 of the sensor chip 100 is covered by the side plate portion 122 of the magnetic collector 120, the back surface 102 of the sensor chip 100 is covered by the connecting portion 123 of the magnetic collector 120 via the dummy chip 130, and the element forming surface 101 of the sensor chip 100 is covered by the overhang portions 124, 125 of the magnetic collector 120.

[0029] Figure 9 is a schematic plan view of the sensor chip 100, and Figure 10 is a schematic cross-sectional view along the line A-A in Figure 9.

[0030] As shown in Figures 9 and 10, four magnetic elements R1 to R4 constituting a bridge circuit are formed on the element formation surface 101 of the sensor chip 100. The magnetic elements R1 to R4 are not particularly limited as long as they are elements whose electrical resistance changes depending on the direction of the magnetic flux, for example, MR elements can be used. The fixed magnetization directions of the magnetic elements R1 to R4 are aligned to be the same direction (for example, the +Y direction). The magnetic elements R1 to R4 are provided on the surface of the insulating layer 107 that covers the element formation surface 101. The magnetic elements R1 to R4 are covered by the insulating layer 108, and magnetic material layers M1 to M3 made of permalloy or the like are formed on the surface of the insulating layer 108. The magnetic material layers M1 to M3 are covered by the insulating layer 109. The magnetic material layer M1 is positioned approximately in the center of the element formation surface 101 in the Y direction. The magnetic layers M2 and M3 are arranged on both sides of the element formation surface 101 in the Y direction, sandwiching the magnetic layer M1 from the Y direction.

[0031] Magnetic layers M1 and M2 form two gaps G1 and G2, with the Y direction as the width direction and extending in the Z direction. The positions of gaps G1 and G2 in the Y direction coincide, and they are aligned in the Z direction. Magnetic layers M1 and M3 form two gaps G3 and G4, with the Y direction as the width direction and extending in the Z direction. The positions of gaps G3 and G4 in the Y direction coincide, and they are aligned in the Z direction. Furthermore, gaps G1 and G3 are aligned in the Y direction, and gaps G2 and G4 are aligned in the Y direction. The magnetic sensing elements R1 to R4 are positioned so that, in a plan view from the X direction, they overlap with gaps G1 to G4. As a result, the magnetic field in the Y direction passing through magnetic gaps G1 to G4 is applied to the magnetic sensing elements R1 to R4, respectively.

[0032] In Figures 9 and 10, the region indicated by reference numeral 110a represents the region covered from the X direction by the YZ plane located at the end of the magnetic collector 110 in the +X direction, and the regions indicated by reference numerals 124a and 125a represent the regions covered from the X direction by the overhang portions 124 and 125 of the magnetic collector 120, respectively.

[0033] Regions 110a, 124a, and 125a overlap with magnetic layers M1 to M3, respectively. As a result, magnetic layer M1 is covered from the X direction by the magnetizer 110, magnetic layer M2 is covered from the X direction by the overhang portion 124 of the magnetizer 120, and magnetic layer M3 is covered from the X direction by the overhang portion 125 of the magnetizer 120. The magnetic field in the X direction emitted from the magnetic material contained in the fluid flowing through the constricted portion 63 of the internal flow path 60 is collected by the magnetizer 110 and applied to magnetic layer M1 via the magnetizer 110. The magnetic field applied to magnetic layer M1 is bent in the +Y and -Y directions within magnetic layer M1. The magnetic flux component bent in the -Y direction in magnetic layer M1 is supplied to magnetic layer M2 via gaps G1 and G2, and then flows to the overhang portion 124, side plate portion 121, and connecting portion 123 of the magnetic collector 120. At this time, a portion of the magnetic flux passing through gaps G1 and G2 in the -Y direction is applied to the magnetic sensing elements R1 and R2. On the other hand, the magnetic flux component bent in the +Y direction in magnetic layer M1 is supplied to magnetic layer M3 via gaps G3 and G4, and then flows to the overhang portion 125, side plate portion 122, and connecting portion 123 of the magnetic collector 120. At this time, a portion of the magnetic flux passing through gaps G3 and G4 in the +Y direction is applied to the magnetic sensing elements R3 and R4.

[0034] While it is not essential to provide overhangs 124 and 125 on the magnetic collector 120, covering the magnetic layers M2 and M3 with the overhangs 124 and 125, respectively, significantly reduces the magnetic resistance between the magnetic collector 110 and the magnetic collector 120. Even if the magnetic collector 120 does not have overhangs 124 and 125, covering the sides 103 and 104 of the sensor chip 100 with the side plates 121 and 122 of the magnetic collector 120 reduces the magnetic resistance between the magnetic collector 110 and the magnetic collector 120. Furthermore, covering the back surface 102 of the sensor chip 100 with the connecting portion 123 of the magnetic collector 120 makes it possible to efficiently apply the magnetic field in the X direction to be detected to the magnetic sensing elements R1 to R4.

[0035] As shown in Figure 10, the sensor chip 100 is provided with a compensation coil C2. The compensation coil C2 is provided, for example, in a position that overlaps with the magnetic sensing elements R1 to R4, and when a compensation current flows through the compensation coil C2, a cancellation magnetic field is applied to the magnetic sensing elements R1 to R4. In the example shown in Figure 10, the compensation coil C2 is provided on the element formation surface 101. Thus, the magnetic sensor S1 has two compensation coils C1 and C2. The application of the cancellation magnetic field to the magnetic sensing elements R1 to R4 may be performed using either the compensation coil C1 or C2, or using both compensation coils C1 and C2.

[0036] As shown in Figures 4 and 5, the magnetic sensors S1 and S2, having this configuration, are positioned to cover the constricted portion 63 of the internal flow path 60 from the Z direction. This ensures that if a foreign object containing a magnetic material is present in the fluid being inspected, the foreign object is magnetized by the magnetization unit 50 shown in Figure 1 before flowing into the foreign object detection unit 20. It is then detected by the magnetic sensors S1 and S2 as it passes through the constricted portion 63 of the internal flow path 60 in the X direction. As shown in Figure 11, if the foreign object 90 is magnetized, the X-direction component of the magnetic field lines 91 generated from the foreign object 90 is detected by the magnetic sensors S1 and S2.

[0037] Furthermore, in this embodiment, the diameter of the internal flow path 60 is not constant, and the diameter is locally reduced in the constricted portion 63 compared to the upstream portion 61 and the downstream portion 62. As a result, the distance between the magnetic sensors S1 and S2 and the foreign object 90 in the Z direction is shortened. This makes it possible to detect magnetic field lines 91 generated from minute foreign objects 90 with high sensitivity. Moreover, since the diameter of the constricted portion 63 of the internal flow path 60 is smaller in the Z direction than in the Y direction, it is possible to further shorten the distance between the magnetic sensors S1 and S2 and the foreign object 90 in the Z direction.

[0038] Furthermore, in this embodiment, since the constricted portion 63 of the internal flow path 60 is sandwiched between the two magnetic sensors S1 and S2 from the Z direction, it is possible to detect magnetic field lines 91 generated from foreign matter 90 with high sensitivity, regardless of the position of the foreign matter 90 passing through the constricted portion 63 of the internal flow path 60 in the Z direction. Moreover, in this embodiment, since the sensitivity position P in the X direction of magnetic sensor S1 and the sensitivity position P in the X direction of magnetic sensor S2 coincide, the magnetic field lines 91 generated from foreign matter 90 can be detected almost simultaneously by the two magnetic sensors S1 and S2. This eliminates the influence of noise and other factors occurring in each of the magnetic sensors S1 and S2, enabling more reliable detection.

[0039] Furthermore, in this embodiment, since the orientation of magnetic sensor S1 in the X direction and the orientation of magnetic sensor S2 in the X direction are reversed by 180° from each other, when foreign matter 90 passes through the throttling portion 63 of the internal flow path 60, the signal waveform obtained from magnetic sensor S1 and the signal waveform obtained from magnetic sensor S2 become symmetrical in the time axis direction, making it possible to more accurately remove the effects of noise and other factors.

[0040] While embodiments of the technology described herein have been explained above, it goes without saying that the technology described herein is not limited to the embodiments described above, and various modifications are possible without departing from its spirit, and these modifications are also included within the scope of the technology described herein.

[0041] For example, the foreign object detection device 10 in the above embodiment has a configuration in which external flow channels 41 and 42 are connected to the foreign object detection unit 20, but it is not necessary for the foreign object detection unit and the external flow channels to be detachable.

[0042] The technology relating to this disclosure includes, but is not limited to, the following configuration examples.

[0043] A foreign matter detection unit according to an aspect of the present disclosure includes: an internal flow path having an upstream section, a downstream section, and a throttle section positioned between the upstream section and the downstream section, the throttle section having a smaller cross-sectional area than the upstream section and the downstream section; and a magnetic sensor arranged to cover the throttle section of the internal flow path and configured to detect a magnetic material contained in a fluid flowing through the throttle section of the internal flow path. According to this configuration, since the distance between the magnetic material and the magnetic sensor is shortened, it becomes possible to detect minute magnetic materials contained in the fluid with high sensitivity.

[0044] In the above foreign matter detection unit, the diameter of the throttle section of the internal flow path in a second direction orthogonal to a first direction is smaller than the diameter thereof in the first direction, and the magnetic sensor may cover the throttle section of the internal flow path from the second direction. According to this configuration, the distance between the magnetic material and the magnetic sensor is further shortened.

[0045] The above foreign matter detection unit may include a plurality of the magnetic sensors. According to this configuration, it becomes possible to detect minute magnetic materials contained in the fluid more accurately. In this case, the plurality of magnetic sensors may be arranged so as to sandwich the throttle section of the internal flow path from the second direction. According to this configuration, the distance between the magnetic material and the magnetic sensors is further shortened. Furthermore, in this case, the sensitivity positions of the plurality of magnetic sensors in the flow direction of the internal flow path may coincide with each other. According to this configuration, it becomes possible to eliminate the influence of noise or the like generated in each of the plurality of magnetic sensors.

[0046] The above foreign matter detection unit may further include a magnetic shield that covers at least the throttle section of the internal flow path and the magnetic sensor. According to this configuration, it becomes possible to eliminate the influence of an external magnetic field.

[0047] A foreign matter detection device according to an aspect of the present disclosure includes: the above foreign matter detection unit; a first external flow path detachably connected to the upstream section of the internal flow path; and a second external flow path detachably connected to the downstream section of the internal flow path. According to this configuration, the foreign matter detection unit can be attached and detached.

[0048] The foreign matter detection device described above may further include a magnetizing unit disposed so as to cover the first external flow path. According to this configuration, since foreign matter containing a magnetic material is magnetized by the magnetizing unit, higher-sensitivity detection can be achieved.

[0049] A foreign matter detection device according to another aspect of the present disclosure includes: a flow path through which a fluid flows; and a magnetic sensor disposed so as to cover the flow path and configured to detect a magnetic material contained in the fluid flowing through the flow path, wherein a cross-sectional area of the flow path is locally reduced in a region where the magnetic sensor is disposed. According to this configuration, even when the diameter of the flow path is large, the distance between the magnetic material and the magnetic sensor is shortened, so that minute magnetic materials contained in the fluid can be detected with high sensitivity.

[0050] This application claims the benefit of Japanese Patent Application No. 2025-051385 filed on March 26, 2025, the entire disclosure of which is incorporated herein by reference.

[0051] 10 Foreign matter detection device 20 Foreign matter detection unit 21, 22 Flow path block 23 Sensor unit 30 Magnetic shield 31, 32 Shield part 41, 42 External flow path 50 Magnetizing unit 60 Internal flow path 61 Upstream part 62 Downstream part 63 Throttling part 70 Substrate 71 Surface 72-79 Electrode pattern 80 Mold resin 90 Foreign matter 91 Magnetic force line 100 Sensor chip 101 Element formation surface 102 Back surface 103-106 Side surface 107-109 Insulating layer 110, 120 Magnetic flux collector 110a, 124a, 125a Region covered by magnetic flux collector 121, 122 Side plate part 123 Connecting part 124, 125 Overhang part 130 Dummy chip 140 Bobbin 141, 142 Terminal fitting C1, C2 Compensation coil G1-G4 Gap M1-M3 Magnetic layer P Sensitivity position R1-R4 Magnetosensitive element S1, S2 Magnetic sensor

Claims

1. A foreign object detection unit comprising: an internal flow path having an upstream section, a downstream section, and a constricted section located between the upstream section and the downstream section, having a smaller cross-sectional area than the upstream section and the downstream section; and a magnetic sensor positioned to cover the constricted section of the internal flow path and for detecting magnetic materials contained in the fluid flowing through the constricted section of the internal flow path.

2. The constricted portion of the internal flow path has a diameter in a second direction perpendicular to the first direction that is smaller than the diameter in the first direction, and the magnetic sensor covers the constricted portion of the internal flow path from the second direction, the foreign object detection unit according to claim 1.

3. The foreign object detection unit according to claim 2, comprising a plurality of the magnetic sensors.

4. The foreign object detection unit according to claim 3, wherein the plurality of magnetic sensors are arranged to sandwich the constricted portion of the internal flow path from the second direction.

5. The foreign object detection unit according to claim 4, wherein the sensitivity positions of the plurality of magnetic sensors in the flow direction of the internal flow path coincide with each other.

6. The foreign object detection unit according to claim 1, further comprising a magnetic shield covering at least the constricted portion of the internal flow path and the magnetic sensor.

7. A foreign object detection device comprising: a foreign object detection unit according to any one of claims 1 to 6; a first external channel detachably connected to the upstream portion of the internal channel; and a second external channel detachably connected to the downstream portion of the internal channel.

8. The foreign object detection device according to claim 7, further comprising a magnetization unit arranged to cover the first external flow path.

9. A foreign object detection device comprising: a fluid channel through which a fluid flows; and a magnetic sensor positioned to cover the fluid channel and to detect magnetic materials contained in the fluid flowing through the channel, wherein the cross-sectional area of ​​the fluid channel is locally reduced in the region where the magnetic sensor is positioned.

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