Magnetic sensor module and magnetic field detection device equipped therewith

Abstract

This invention provides a magnetic sensor module having a structure in which a magnetic sensor and various circuits are integrated. [Solution] The magnetic sensor module 100 comprises a support body 110, a magnetic sensor 120 fixed to the support body 110, a circuit board 130 fixed to the support body 110 and connected to the magnetic sensor 120, connecting members 151 and 152 fixed to the circuit board 130, and a circuit board 140 fixed to the circuit board 130 via the connecting members 151 and 152 and connected to the magnetic sensor 120 via the connecting members 151 and 152 and the circuit board 130. The connecting members 151 and 152 support the circuit board 140 such that a space is formed between the circuit board 130 and the circuit board 140.

Description

Technical Field

[0001] The present disclosure relates to a magnetic sensor module, and particularly to a magnetic sensor module with excellent heat dissipation. The present disclosure also relates to a magnetic field detection device capable of detecting a magnetic field in three axial directions by including a plurality of the above-described magnetic sensor modules. Background Art

[0002] Patent Literature 1 discloses a magnetic field detection device capable of detecting a magnetic field in three axial directions. Prior Art Literature Patent Literature

[0003] Patent Literature 1 Japanese Utility Model Laid-Open Publication No. 58-047181 Summary of the Invention Problem to be Solved by the Invention

[0004] However, the magnetic field detection device disclosed in Patent Literature 1 is not provided with a space for accommodating various circuits connected to a magnetic sensor, so it has been necessary to separately connect the magnetic field detection device to a circuit board on which these circuits are formed.

[0005] In the present disclosure, a magnetic sensor module which can be applied to a magnetic field detection device capable of detecting a magnetic field in three axial directions and has a structure in which a magnetic sensor and various circuits are integrated is described. Means for Solving the Problem

[0006] A magnetic sensor module according to one aspect of the present disclosure comprises a support, a magnetic sensor fixed to the support, a first circuit board fixed to the support and connected to the magnetic sensor, a connecting member fixed to the first circuit board, and a second circuit board fixed to the first circuit board via the connecting member and connected to the magnetic sensor via the connecting member and the first circuit board. The connecting member supports the second circuit board such that a space is formed between the first circuit board and the second circuit board. [Effects of the Invention]

[0007] According to this disclosure, a magnetic sensor module having a structure in which a magnetic sensor and various circuits are integrated is provided. [Brief explanation of the drawing]

[0008] [Figure 1] Figures 1(a) and 1(b) are schematic perspective views showing the external appearance of a magnetic field detection device 10 according to one embodiment of the technology described herein, and depict the device as viewed from different directions. [Figure 2] Figure 2 is a schematic perspective view showing the magnetic field detection device 10 with the fixing member 400 removed. [Figure 3] Figure 3 is a schematic perspective view showing the magnetic field detection device 10 with the magnetic sensor module 200 removed. [Figure 4] Figure 4 is a schematic perspective view showing the magnetic field detection device 10 with the magnetic sensor module 300 removed. [Figure 5] Figure 5 is a schematic perspective view showing the cube-shaped components of the magnetic field detection device 10 housed in the outer case 30. [Figure 6] Figures 6(a) and 6(b) are schematic perspective views showing the external appearance of the magnetic sensor module 100, representing views from different directions. [Figure 7] Figures 7(a) and 7(b) are approximate perspective views showing the external appearance of the support 110, representing views from different directions. [Figure 8] Figure 8 is a circuit diagram showing an example of the circuits formed on the magnetic sensor 120 and the circuit boards 130 and 140. [Figure 9] Figures 9(a) and 9(b) are schematic perspective views showing the external appearance of the magnetic sensor module 200, representing views from different directions. [Figure 10] Figures 10(a) and (b) are approximate perspective views showing the external appearance of the support 210, representing views from different directions. [Figure 11] Figures 11(a) and (b) are schematic perspective views showing the external appearance of the magnetic sensor module 300, representing views from different directions. [Figure 12] Figures 12(a) and (b) are approximate perspective views showing the external appearance of the support 310, representing views from different directions. [Figure 13] Figures 13(a) and (b) are approximate perspective views showing the external appearance of the fixing member 400, and depict it as viewed from different directions. [Figure 14] Figure 14 is a schematic diagram of a cube body 40 consisting of magnetic sensor modules 100, 200, and 300. [Modes for carrying out the invention]

[0009] The embodiments of the technology described herein will be described in detail below with reference to the attached drawings.

[0010] Figures 1(a) and 1(b) are schematic perspective views showing the external appearance of a magnetic field detection device 10 according to one embodiment of the technology described herein, and depict the device as viewed from different directions.

[0011] As shown in Figures 1(a) and 1(b), the magnetic field detection device 10 according to this embodiment comprises three magnetic sensor modules 100, 200, and 300, a fixing member 400, and a circuit board 20. The magnetic sensor modules 100, 200, and 300 engage with each other in a cube-like manner to form a cube. The circuit board 20 is positioned in the corner region 11 of the cube. The fixing member 400 is positioned in the corner region 12 of the cube. The corner regions 11 and 12 are located diagonally opposite each other.

[0012] Fig. 2 is a schematic perspective view showing a state where the fixing member is removed from the magnetic field detection device 10.

[0013] As shown in Fig. 2, when the fixing member 400 is removed, a space is formed in the corner region 12 of the cube body. In this space, the XZ plane of the magnetic sensor module 100, the XY plane of the magnetic sensor module 200, and the YZ plane of the magnetic sensor module 300 are exposed. The X direction, Y direction, and Z direction are directions orthogonal to each other. Then, the fixing member 400 is disposed in this space, and the fixing member 400 is screwed to the magnetic sensor modules 100, 200, 300 with screws, whereby these members are fixed to each other. The magnetic sensor module 100 and the magnetic sensor module 200, the magnetic sensor module 100 and the magnetic sensor module 300, as well as the magnetic sensor module 200 and the magnetic sensor module 300 are also fixed to each other by screwing.

[0014] Fig. 3 is a schematic perspective view showing a state where the magnetic sensor module 200 is removed from the magnetic field detection device 10. Further, Fig. 4 is a schematic perspective view showing a state where the magnetic sensor module 300 is removed from the magnetic field detection device 10.

[0015] As shown in Figs. 3 and 4, the magnetic sensor module 100 and the fixing member 400 are connected in the Y direction, the magnetic sensor module 200 and the fixing member 400 are connected in the Z direction, and the magnetic sensor module 300 and the fixing member 400 are connected in the X direction. Further, the magnetic sensor module 100 and the magnetic sensor module 200 are connected in the Z direction, the magnetic sensor module 100 and the magnetic sensor module 300 are connected in the Y direction, and the magnetic sensor module 200 and the magnetic sensor module 300 are connected in the X direction.

[0016] Fig. 5 is a schematic perspective view showing a state where the cube body constituting the magnetic field detection device 10 is accommodated in the outer case 30.

[0017] As shown in Figure 5, the outer casing 30 has multiple ventilation holes 31 on its walls, which efficiently dissipate the heat generated by the magnetic field detection device 10 to the outside. The outer casing 30 is made of, for example, resin. Cables 32 that are drawn out from the magnetic field detection device 10 through the outer casing 30 are connected to the magnetic sensor modules 100, 200, and 300, respectively, via the circuit board 20.

[0018] Figures 6(a) and 6(b) are schematic perspective views showing the external appearance of the magnetic sensor module 100, representing views from different directions.

[0019] As shown in Figures 6(a) and 6(b), the magnetic sensor module 100 includes a support 110, a magnetic sensor 120 fixed to the support 110, a circuit board 130 fixed to the support 110, and a circuit board 140 fixed to the circuit board 130 via connecting members 151 and 152 so as to overlap the circuit board 130. The support 110 may be a molded material such as resin.

[0020] Figures 7(a) and 7(b) are approximate perspective views showing the external appearance of the support 110, representing views from different directions.

[0021] As shown in Figures 7(a) and 7(b), the support 110 is a member whose longitudinal direction is in the X direction, and has a housing portion 112 extending in the X direction and a housing portion 113 overlapping the housing portion 112 in the Z direction. The magnetic sensor 120 is housed in the housing portion 112. The circuit board 130 is housed in the housing portion 113. The circuit board 130 is connected to the magnetic sensor 120. The circuit board 140 is connected to the magnetic sensor 120 via connecting members 151, 152 and the circuit board 130. The main surfaces of the circuit boards 130 and 140 both face in the -Z direction. That is, the main surface of the circuit board 130 and the back surface of the circuit board 140 face each other in the Z direction with space in between. This allows air to flow in the X direction through the space formed between the circuit boards 130 and 140.

[0022] Figure 8 is a circuit diagram showing an example of the circuits formed on the magnetic sensor 120 and the circuit boards 130 and 140.

[0023] In the example shown in Figure 8, the magnetic sensor 120 includes four sensor elements MR1 ​​to MR4 that detect a magnetic field in the X direction, and a compensation coil C that cancels the magnetic field applied to sensor elements MR1 ​​to MR4. Sensor elements MR1 ​​and MR2 are connected in series, and a detection signal Va is output from their connection point. Sensor elements MR3 and MR4 are connected in series, and a detection signal Vb is output from their connection point. The potential difference between the detection signals Va and Vb generated by such a bridge circuit is amplified by a differential amplifier A, and a compensation current I is generated. The current value of the compensation current I is converted into a voltage by a resistor R1, and an output signal Vout is generated. The output signal Vout is the final output signal of the magnetic sensor module 100. Furthermore, the compensation current I is divided into a shunt resistor R2 and a compensation coil C connected in parallel, and a cancellation magnetic field generated by a portion of the compensation current I flowing through the compensation coil C is applied to sensor elements MR1 ​​to MR4. It is also possible to let the entire compensation current I flow through the compensation coil C without using the shunt resistor R2.

[0024] In the circuit shown in Figure 8, the sensor elements MR1 ​​to MR4 and the compensation coil C are integrated into the magnetic sensor 120, the bridge circuit connecting the sensor elements MR1 ​​to MR4 and the differential amplifier A are formed on the circuit board 140, and the compensation circuit including the shunt resistor R2 and resistor R1 are formed on the circuit board 130.

[0025] As shown in Figure 6(a), the connecting member 151 supports circuit board 140 such that a space is formed between circuit board 130 and circuit board 140. This improves the heat dissipation of circuit board 130, which generates a large amount of heat due to the compensation current I. Furthermore, wiring is formed on circuit board 130 so that the compensation current I or its shunt flows in the X direction. For example, a shunt resistor R2 through which a portion of the compensation current I flows extends in the X direction on circuit board 130. The X direction is the sensitivity axis direction of the magnetic sensor 120. As a result, the magnetic field generated by the compensation current I or its shunt flowing on circuit board 130 circulates around the X direction, making it less likely to become noise for the magnetic sensor 120. The current flowing through resistor R1 may also be arranged to flow in the X direction, which is the sensitivity axis direction of the magnetic sensor 120.

[0026] Figures 9(a) and 9(b) are schematic perspective views showing the external appearance of the magnetic sensor module 200, representing views from different directions.

[0027] As shown in Figures 9(a) and (b), the magnetic sensor module 200 includes a support 210, a magnetic sensor 220 fixed to the support 210, a circuit board 230 fixed to the support 210, and a circuit board 240 fixed to the circuit board 230 via connecting members 251 and 252 so as to overlap the circuit board 230. The support 210 may be a molded material such as resin.

[0028] Figures 10(a) and (b) are approximate perspective views showing the external appearance of the support 210, representing views from different directions.

[0029] As shown in Figures 10(a) and (b), the support 210 is a member whose longitudinal direction is in the Y direction, and has a housing portion 212 extending in the Y direction and a housing portion 213 overlapping the housing portion 212 in the X direction. The magnetic sensor 220 is housed in the housing portion 212. The circuit board 230 is housed in the housing portion 213. The circuit board 230 is connected to the magnetic sensor 220. The circuit board 240 is connected to the magnetic sensor 220 via connecting members 251, 252 and the circuit board 230. The main surfaces of the circuit boards 230 and 240 both face in the -X direction. That is, the main surface of the circuit board 230 and the back surface of the circuit board 240 face each other in the X direction with space in between. This allows air to flow in the Y direction through the space formed between the circuit boards 230 and 240.

[0030] The circuits formed on the magnetic sensor 220 and the circuit boards 230 and 240 are as shown in Figure 8.

[0031] Figures 11(a) and (b) are schematic perspective views showing the external appearance of the magnetic sensor module 300, representing views from different directions.

[0032] As shown in Figures 11(a) and (b), the magnetic sensor module 300 includes a support 310, a magnetic sensor 320 fixed to the support 310, a circuit board 330 fixed to the support 310, and a circuit board 340 fixed to the circuit board 330 via connecting members 351 and 352 so as to overlap the circuit board 330. The support 310 may be a molded material such as resin.

[0033] Figures 12(a) and (b) are approximate perspective views showing the external appearance of the support 310, representing views from different directions.

[0034] As shown in Figures 12(a) and (b), the support 310 is a member whose longitudinal direction is in the Z direction, and has a housing portion 312 extending in the Z direction, a housing portion 313 overlapping with the housing portion 312 in the Y direction, and a plate-like portion 314 having a YZ plane. The magnetic sensor 320 is housed in the housing portion 312. The circuit board 330 is housed in the housing portion 313. The circuit board 330 is connected to the magnetic sensor 320. The circuit board 340 is connected to the magnetic sensor 320 via connecting members 351, 352 and the circuit board 330. The main surfaces of the circuit boards 330 and 340 both face in the -Y direction. That is, the main surface of the circuit board 330 and the back surface of the circuit board 340 face each other in the Y direction with space in between. This allows air to flow in the Z direction through the space formed between the circuit boards 330 and 340.

[0035] The circuits formed on the magnetic sensor 320 and the circuit boards 330 and 340 are as shown in Figure 8.

[0036] Furthermore, a circuit board 20 is placed on the plate-shaped portion 314 of the support 310. The circuit board 20 is connected to the circuit board 140 included in the magnetic sensor module 100, the circuit board 240 included in the magnetic sensor module 200, and the circuit board 340 included in the magnetic sensor module 300. As a result, the magnetic sensor modules 100, 200, and 300 are controlled by the circuit board 20, and the output signal Vout output from the magnetic sensor modules 100, 200, and 300 is supplied to the circuit board 20.

[0037] In this embodiment, the support 110 included in the magnetic sensor module 100, the support 210 included in the magnetic sensor module 200, and the support 310 included in the magnetic sensor module 300 have different shapes. This makes it easy to distinguish between the supports 110, 210, and 310 during assembly. However, this is not essential, and the shapes of the supports 110, 210, and 310 may be the same.

[0038] Figures 13(a) and (b) are approximate perspective views showing the external appearance of the fixing member 400, and depict it as viewed from different directions.

[0039] As shown in Figures 13(a) and (b), the fixing member 400 has screw holes 401 to 403. The fixing member 400 and the magnetic sensor module 100 are fixed by a screw inserted into screw hole 401, the fixing member 400 and the magnetic sensor module 200 are fixed by a screw inserted into screw hole 402, and the fixing member 400 and the magnetic sensor module 300 are fixed by a screw inserted into screw hole 403.

[0040] Figure 14 is a schematic diagram of a cube body 40 consisting of magnetic sensor modules 100, 200, and 300.

[0041] As shown in Figure 14, the cube body 40 has a roughly cubic shape and has edges X1 to X4 extending in the X direction, edges Y1 to Y4 extending in the Y direction, and edges Z1 to Z4 extending in the Z direction. A magnetic sensor 120 is positioned at the position corresponding to edge X1 with the X axis as the sensitivity axis direction, a magnetic sensor 220 is positioned at the position corresponding to edge Y1 with the Y axis as the sensitivity axis direction, and a magnetic sensor 320 is positioned at the position corresponding to edge Z1 with the Z axis as the sensitivity axis direction. This constitutes a magnetic field detection device 10 capable of detecting magnetic fields in three axial directions.

[0042] Here, edges X1, Y1, and Z1 are positioned so that they do not share any corners with each other. In this way, the magnetic sensors 120, 220, and 320 are positioned along the non-intersecting (not sharing any common vertices) edges X1, Y1, and Z1 of the cube 40, respectively, ensuring a distance between the sensor heads of the magnetic sensors 120, 220, and 320. This makes it possible to reduce magnetic interference between the magnetic sensors 120, 220, and 320.

[0043] Furthermore, the corner formed by side X2, which is in the same position as side X1 in the Y direction but different in the Z direction; side Y2, which is in the same position as side Y1 in the Z direction but different in the X direction; and side Z2, which is in the same position as side Z1 in the X direction but different in the Y direction, is located in the corner region 11. Circuit boards 130 and 140 included in the magnetic sensor module 100, circuit boards 230 and 240 included in the magnetic sensor module 200, circuit boards 330 and 340 included in the magnetic sensor module 300, and circuit board 20 are all arranged together in the corner region 11. A region enclosed by circuit boards 20, 130, 230, and 330 is formed in the corner region 11, and circuit boards 140, 240, and 340 are arranged in this region so as not to interfere with each other.

[0044] Thus, because the circuit board is concentrated in the corner region 11, which is far from the sides X1, Y1, and Z1 where the magnetic sensors 120, 220, and 320 are located, the circuit board is less likely to become a noise source for the magnetic sensors 120, 220, and 320.

[0045] Furthermore, the corner formed by side X3, which is in the same position as side X1 in the Z direction but different in the Y direction; side Y3, which is in the same position as side Y1 in the X direction but different in the Z direction; and side Z3, which is in the same position as side Z1 in the Y direction but different in the X direction, is located in the corner region 12. A fixing member 400 is placed in the corner region 12.

[0046] In this way, by positioning the fixing member 400 in another corner region 12 that is away from the sides X1, Y1, Z1 where the magnetic sensors 120, 220, and 320 are located, it becomes possible to connect the supports 110, 210, and 310 to each other while preventing interference with the magnetic sensors 120, 220, and 320.

[0047] 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.

[0048] The technology relating to this disclosure includes, but is not limited to, the following configuration examples.

[0049] A magnetic sensor module according to one aspect of this disclosure comprises a support, a magnetic sensor fixed to the support, a first circuit board fixed to the support and connected to the magnetic sensor, a connecting member fixed to the first circuit board, and a second circuit board fixed to the first circuit board via the connecting member and connected to the magnetic sensor via the connecting member and the first circuit board. The connecting member supports the second circuit board such that a space is formed between the first circuit board and the second circuit board. This allows air to circulate through the space formed between the first circuit board and the second circuit board, making it possible to provide a magnetic sensor module with excellent heat dissipation.

[0050] In the magnetic sensor module described above, the magnetic sensor may include a plurality of sensor elements and a compensation coil, the second circuit board may include a bridge circuit that bridges the plurality of sensor elements, and the first circuit board may include a compensation circuit that supplies a compensation current to the compensation coil based on a detection signal output from the bridge circuit. In this configuration, the heat generated by the compensation current is dissipated through the space formed between the first circuit board and the second circuit board.

[0051] In the magnetic sensor module described above, the compensation current or its shunt on the first circuit board may flow along the direction of magnetic sensing of the magnetic sensor. This makes it less likely for the compensation current to become a noise source for the magnetic sensor.

[0052] A magnetic field detection device according to one aspect of this disclosure comprises first, second, and third magnetic sensor modules having the same configuration as the magnetic sensor module described above and engaging with each other. The magnetic sensing direction of the magnetic sensor included in the first magnetic sensor module may be a first direction, the magnetic sensing direction of the magnetic sensor included in the second magnetic sensor module may be a second direction orthogonal to the first direction, and the magnetic sensing direction of the magnetic sensor included in the third magnetic sensor module may be a third direction orthogonal to the first and second directions. This provides a magnetic field detection device capable of detecting magnetic fields in three axial directions.

[0053] In the magnetic field detection device described above, the first, second, and third magnetic sensor modules may be engaged in a cube-like manner to form a cube body. This makes it easier to construct a magnetic field detection device array consisting of a collection of multiple magnetic field detection devices.

[0054] The magnetic field detection device described above may further include an outer case that houses the cube and has ventilation holes. This allows the cube to be protected by the outer case, and high heat dissipation can be achieved through the circulation of air via the ventilation holes.

[0055] In the magnetic field detection device described above, the main surfaces of the first and second circuit boards included in the first magnetic sensor module, the main surfaces of the first and second circuit boards included in the second magnetic sensor module, and the main surfaces of the first and second circuit boards included in the third magnetic sensor module are orthogonal to each other, and the first and second circuit boards included in the first, second, and third magnetic sensor modules may be concentrated in the first corner region of the cube. This makes it less likely for the circuit boards to become a noise source for the magnetic sensor.

[0056] The magnetic field detection device described above is connected to a second circuit board included in the first, second, and third magnetic sensor modules, and further comprises a third circuit board positioned in the first corner region, wherein the third circuit board may be fixed to a support included in any of the first, second, and third magnetic sensor modules. This eliminates the need to use a separate support for supporting the third circuit board.

[0057] The magnetic field detection device described above may further include fixing members that are positioned in the second corner region diagonally opposite the first corner region of the cube body and are fixed to the supports included in the first, second, and third magnetic sensor modules, respectively. This makes it possible to firmly fix the first, second, and third magnetic sensor modules to each other. [Explanation of Symbols]

[0058] 10 Magnetic field detection device 11,12 Corner area 20, 130, 140, 230, 240, 330, 340 Circuit board 30 outer cases 31 Ventilation holes 32 Cables 40 cubes 100, 200, 300 Magnetic Sensor Modules 110,210,310 Support 112,113,212,213,312,313 Housing section 120,220,320 Magnetic Sensors 151, 152, 251, 252, 351, 352 Connecting members 314 Plate-like part 400 Fixing member 401-403 Screw holes A differential amplifier C Compensation coil I compensation current MR1~MR4 Sensor Elements R1 Resistor R2 Shunt resistor Va, Vb detection signals VOUT output signal X1~X4, Y1~Y4, Z1~Z4 edges

Claims

1. Support and A magnetic sensor fixed to the support, A first circuit board fixed to the support and connected to the magnetic sensor, A connecting member fixed to the first circuit board, A second circuit board is fixed to the first circuit board via the connecting member and connected to the magnetic sensor via the connecting member and the first circuit board, Equipped with, The connecting member supports the second circuit board such that a space is formed between the first circuit board and the second circuit board. Magnetic sensor module.

2. The magnetic sensor includes a plurality of sensor elements and a compensation coil. The second circuit board includes a bridge circuit that bridges the plurality of sensor elements, The first circuit board includes a compensation circuit that supplies a compensation current to the compensation coil based on a detection signal output from the bridge circuit. The magnetic sensor module according to claim 1.

3. On the first circuit board, the compensation current or its subdivision flows along the magnetic sensing direction of the magnetic sensor. The magnetic sensor module according to claim 2.

4. The present invention comprises first, second, and third magnetic sensor modules having the same configuration as the magnetic sensor module described in any one of claims 1 to 3 and engaging with each other, The magnetic sensing direction of the magnetic sensor included in the first magnetic sensor module is the first direction, The magnetic sensing direction of the magnetic sensor included in the second magnetic sensor module is a second direction perpendicular to the first direction. The magnetic sensing direction of the magnetic sensor included in the third magnetic sensor module is a third direction perpendicular to the first and second directions. Magnetic field detection device.

5. The first, second, and third magnetic sensor modules are engaged in a cube-like manner to form a cube body. The magnetic field detection device according to claim 4.

6. The aforementioned cube body is housed in an outer case having ventilation holes, The magnetic field detection device according to claim 5.

7. The main surfaces of the first and second circuit boards included in the first magnetic sensor module, the main surfaces of the first and second circuit boards included in the second magnetic sensor module, and the main surfaces of the first and second circuit boards included in the third magnetic sensor module are orthogonal to each other. The first and second circuit boards included in the first, second, and third magnetic sensor modules are concentrated and arranged in the first corner region of the cube body. The magnetic field detection device according to claim 5.

8. The first, second, and third magnetic sensor modules further include a third circuit board connected to the second circuit board and positioned in the first corner region, The third circuit board is fixed to the support included in any of the first, second, and third magnetic sensor modules. The magnetic field detection device according to claim 7.

9. The system further comprises fixing members positioned in the second corner region located diagonally opposite the first corner region of the cube body, and fixed to the support included in the first, second, and third magnetic sensor modules, respectively. The magnetic field detection device according to claim 7.

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