JP2017015658A - Rotation angle detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation angle detection device capable of improving rotation angle detection accuracy due to a magnetic sensing element while suppressing adverse effects of a magnetic noise from a driving circuit.SOLUTION: A rotation angle detection device 1 detects a rotation angle of a motor 15 having a shaft 18 passing through a heat dissipation plate 10. The rotation angle detection device 1 includes a permanent magnet 30 mounted on a base end portion 18b of the shaft 18, a substrate 31 which is arranged on the heat dissipation plate 10 and has a driving circuit 34 of a motor 15 mounted thereon, a magnetic sensor 32 provided on the substrate 31 so as to face the permanent magnet 30, a cylindrical magnetic shielding member 42 which is arranged between the heat dissipation plate 10 and the substrate 31 and surrounds the permanent magnet 30 in plan view, and a sealing resin 51 which contains a magnetic material and is formed on the substrate 31 for sealing at least a part of the magnetic sensor 32.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rotation angle detection device including a permanent magnet and a magnetically sensitive element.

In recent years, a non-contact type rotation angle detection device that detects a rotation angle of a motor by using a permanent magnet and a magnetic sensitive element that are arranged apart from each other has been proposed. Such a rotation angle detection device is disclosed in Patent Document 1, for example.
Patent Document 1 discloses a motor case, a motor housed in the motor case, a first frame (metal plate) that closes the motor case, and a first frame (metal plate) spaced from the first frame (metal plate). ), A power board (board) disposed on the control board spaced from the control board, and a rotation angle detection device. The motor includes a shaft (rotating shaft) that penetrates through the first frame (metal plate) and has one end protruding above the first frame (metal plate).

  Various electronic parts such as a microcomputer are mounted on the control board, and a drive circuit including various electronic parts such as a switching element is mounted on the power board. The rotation angle detection device includes a magnet (permanent magnet) attached to one end portion of a shaft (rotation shaft) and a position detection sensor (magnetic sensitive element) attached to a control board. The magnet (permanent magnet) and the position detection sensor (magnetic sensitive element) are arranged to face each other.

JP 2014-225998 A

In Patent Document 1, a case will be considered in which a substrate on which a drive circuit is mounted is disposed close to a magnetic sensitive element in order to further reduce the size. In this case, as a result of the electromagnetic noise generated by the current flowing through the drive circuit being detected by the magnetic sensitive element, there is a possibility that distortion, noise or the like may occur in the rotation angle detection signal of the magnetic sensitive element.
Therefore, an object of the present invention is to provide a rotation angle detection device that can improve the rotation angle detection accuracy by a magnetically sensitive element while suppressing the adverse effects of electromagnetic noise from a drive circuit.

  The invention according to claim 1 is a rotation angle detection device (1, 60) for detecting a rotation angle of a motor (15) having a rotation shaft (18) penetrating a metal plate (10), wherein the rotation shaft A permanent magnet (30) attached to one end (18b) on the side penetrating the metal plate, and facing the metal plate on the opposite side of the metal plate to the permanent magnet, and the motor A substrate (31) on which the drive circuit (34) is mounted, a magnetic sensitive element (32) provided on the substrate so as to face the permanent magnet, and a plane between the metal plate and the substrate. A cylindrical magnetic shielding member (42) disposed so as to surround the permanent magnet as viewed, and a seal formed on the substrate so as to seal at least a part of the magnetically sensitive element, including a magnetic material. Rotation angle detection device (including stop resin (51)) , It is 60). In addition, although the alphanumeric characters in parentheses represent corresponding components in the embodiments described later, the scope of the claims is not intended to be limited to the embodiments. The same applies hereinafter.

  According to this configuration, the magnetic path connecting the magnetic sensitive element and the drive circuit can be shielded by the magnetic shielding member, so that electromagnetic noise generated in the drive circuit can be prevented from reaching the magnetic sensitive element. Thereby, it can suppress that the electromagnetic noise which generate | occur | produced in the drive circuit is detected by a magnetic sensitive element. Furthermore, at least a part of the magnetically sensitive element is sealed with a sealing resin containing a magnetic material. Thereby, since the magnetic resistance between a permanent magnet and a magnetic sensitive element can be reduced, the magnetism from a permanent magnet can be satisfactorily detected by the magnetic sensitive element. As a result, the magnetism from the permanent magnet can be satisfactorily detected by the magnetic sensitive element, so that the rotation angle detection accuracy of the magnetic sensitive element can be improved.

  According to a second aspect of the present invention, the magnetic shielding member is provided integrally with the metal plate, and the sealing resin fits into the inner wall (42a) of the magnetic shielding member. It is a rotation angle detection apparatus of Claim 1 formed on the top. According to this configuration, since the sealing resin formed on the substrate can be fitted to the inner wall of the magnetic shielding member, the accuracy of positioning the substrate with respect to the metal plate can be improved. Thereby, the positioning accuracy of the magnetic sensitive element with respect to the permanent magnet is also improved, so that the rotational angle detection accuracy of the magnetic sensitive element can be further improved.

  According to a third aspect of the present invention, the sealing resin is formed on the substrate so as to seal the entire region of the magnetically sensitive element, and is a concave surface (52a) recessed toward the substrate side. It is a rotation angle detection apparatus of Claim 1 or 2 which has these. According to this configuration, the permanent magnet and the magnetically sensitive element can be arranged close to each other while increasing the proportion of the sealing resin that occupies the space surrounded by the magnetic shielding member. As a result, the rotation angle detection accuracy of the magnetic sensitive element can be further improved.

  According to a fourth aspect of the present invention, the magnetic shielding member includes a cylindrical main body (43) having an inner wall and an outer wall, and a plating layer including a magnetic material formed on at least one of the inner wall and the outer wall of the main body. It is a rotation angle detection apparatus as described in any one of Claims 1-3 which has (44).

FIG. 1 is a schematic cross-sectional view showing an integrated motor / ECU to which a rotation angle detection device according to an embodiment of the present invention is applied. FIG. 2 is an enlarged cross-sectional view showing the magnetic shielding member and the sealing resin of FIG. FIG. 3 is a cross-sectional view taken along the line III-III shown in FIG. FIG. 4 is an enlarged cross-sectional view showing a main part of a rotation angle detection device according to a modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic cross-sectional view showing an integrated motor / ECU (Electronic Control Unit) 101 to which a rotation angle detection device 1 according to an embodiment of the present invention is applied.
In the present embodiment, the integrated motor / ECU 101 is an integrated motor / ECU for EPS (Electric Power Steering) that integrally includes a motor 15 described later and an ECU 48. Hereinafter, the configuration of the integrated motor / ECU 101 will be described more specifically.

  The integrated motor / ECU 101 includes a motor housing 2. The motor housing 2 is integrally provided with a disk-shaped bottom wall 3 and a cylindrical side wall 5 provided on the periphery of the bottom wall 3 and forming an opening 4 on the opposite side of the bottom wall 3. It has a bottom cylindrical shape. The motor housing 2 has a first bearing holding portion 7 for holding the first bearing 6 on the bottom wall 3. The first bearing holding portion 7 is a recess that is recessed by one step in a substantially circular shape in plan view at the center portion of the bottom wall 3. The first bearing 6 is accommodated and held in the recess. In the present embodiment, the first bearing 6 is a ball bearing. A through hole 8 that penetrates the bottom wall 3 is formed at the center of the bottom surface of the first bearing holding portion 7. The opening 4 of the motor housing 2 is closed by a substantially disc-shaped metal (for example, aluminum) heat radiating plate (metal plate) 10.

  The heat radiating plate 10 has a first main surface 10 a facing the bottom wall 3 of the motor housing 2 and a second main surface 10 b opposite to the first main surface 10 a. The heat sink 10 has the 2nd bearing holding part 12 for hold | maintaining the 2nd bearing 11 in the center part of the 1st main surface 10a. The second bearing holding portion 12 is a recess that is recessed by one step in a substantially circular shape in plan view in the central portion of the first main surface 10a of the heat radiating plate 10. The second bearing 11 is accommodated and held in the recess. In the present embodiment, the second bearing 11 is a ball bearing. A through hole 13 that penetrates the heat radiating plate 10 is formed at the center of the bottom surface of the second bearing holding portion 12. A motor 15 is accommodated in the motor housing 2 closed by the heat radiating plate 10.

In the present embodiment, the motor 15 is a three-phase brushless motor. The motor 15 passes through a cylindrical stator 16 fixed to the inner peripheral surface 5 a of the side wall 5 of the motor housing 2, a rotor 17 disposed on the radially inner side of the stator 16, and a central portion of the rotor 17. And a cylindrical shaft (rotary shaft) 18 attached to the rotor 17.
The stator 16 has a plurality of stator teeth 19 extending radially inward from the inner peripheral surface 5 a of the side wall 5 of the motor housing 2, and a stator winding 20 wound around the plurality of stator teeth 19. doing. Stator winding 20 includes a U-phase winding, a V-phase winding, and a W-phase winding corresponding to the U-phase, V-phase, and W-phase of motor 15. A cylindrical motor bus bar 21 is electrically connected to one end 20a of the stator winding 20 located on the heat radiating plate 10 side. The motor bus bar 21 is drawn out to the second main surface 10 b side of the heat sink 10 through a bus bar insertion hole 22 formed in the heat sink 10.

  The rotor 17 includes a cylindrical rotor core 23 that rotates integrally with the shaft 18, and a permanent magnet 24 fixed to the outer periphery of the rotor core 23. The rotor core 23 is made of a soft magnetic material, and a shaft insertion hole 25 is formed in the central portion in plan view. The permanent magnet 24 is a ring-shaped magnet in which S poles and N poles are alternately magnetized along the circumferential direction of the rotor core 23.

  The shaft 18 is inserted into the shaft insertion hole 25 of the rotor core 23 and fixed. The shaft 18 is made of a nonmagnetic metal such as stainless steel (SUS). The shaft 18 is pivotally supported by a first bearing 6 provided on the bottom wall 3 of the motor housing 2 and a second bearing 11 provided on the first main surface 10 a of the heat sink 10. Thereby, the rotor 17 is rotatably supported in the motor housing 2. In this configuration, the shaft 18 passes through the through hole 8 and protrudes to the outside of the motor housing 2, and a base end that passes through the through hole 13 and protrudes toward the second main surface 10 b of the heat sink 10. Part (one end part) 18b.

  A connecting member 26 is attached to the tip 18 a of the shaft 18. The connecting member 26 is connected to an external mechanism (for example, a reduction gear for EPS) of the integrated motor / ECU 101, whereby the rotational driving force of the motor 15 is applied to the external mechanism (for example, a reduction gear for EPS). To communicate. On the other hand, a substantially disc-shaped permanent magnet 30 is attached to the base end portion 18 b of the shaft 18 so as to rotate integrally with the shaft 18. The permanent magnet 30 is formed by alternately magnetizing S and N poles along the circumferential direction. As shown in FIG. 1, the permanent magnet 30 may be formed wider than the radial width of the shaft 18 so that the peripheral edge 30a of the permanent magnet 30 faces the second main surface 10b. The permanent magnet 30 may be formed with a width substantially the same as the radial width of the shaft 18. A substantially disc-shaped substrate 31 is disposed on the opposite side of the permanent magnet 30 from the heat sink 10 so as to face the second main surface 10b of the heat sink 10.

  The substrate 31 is disposed at a predetermined interval (for example, about 5 mm) from the heat sink 10 in the axial direction of the shaft 18, and is opposed to the opposing surface 31 a that opposes the second main surface 10 b of the heat sink 10. And a non-facing surface 31b. The substrate 31 may be a multilayer wiring substrate, for example. The multilayer wiring board may have a plurality of insulating layers, a plurality of wiring layers, and vias that electrically connect the wiring layers arranged above and below the insulating layer. A sensor mounting region 33 having a substantially circular shape in a plan view in which a magnetic sensor (magnetic sensitive element) 32 is mounted is set at the center of the opposing surface 31 a of the substrate 31. A driving circuit mounting area 35 having a substantially annular shape in plan view on which the driving circuit 34 is mounted is set to surround the sensor mounting area 33 at the peripheral edge of the facing surface 31 a of the substrate 31.

  The magnetic sensor 32 is disposed in a region facing the entire plate surface 30 b of the permanent magnet 30 in the sensor mounting region 33. More specifically, the magnetic sensor 32 is disposed at a position that coincides with the rotation center of the shaft 18 on the facing surface 31 a of the substrate 31. Thereby, the magnetic sensor 32 is opposed to the permanent magnet 30 with a space in between. The magnetic sensor 32 detects a magnetic field (magnetic flux) from the permanent magnet 30 that varies with the rotation of the shaft 18. The permanent magnet 30 and the magnetic sensor 32 constitute a part of the rotation angle detection device 1. The rotation angle detection device 1 includes calculation means (not shown) that calculates the rotation angle of the motor 15 based on the output of the magnetic sensor 32.

  The drive circuit 34 is a three-phase inverter circuit that supplies electric power to the motor 15, and includes a plurality of switching elements 36 corresponding to the U phase, the V phase, and the W phase of the motor 15. Each switching element 36 is thermally connected to the heat radiating plate 10 via a metal heat radiating member 37. Each switching element 36 and the heat radiating member 37 connected to each switching element 36 are sealed with a sealing resin 38 formed on the substrate 31. An example of the sealing resin 38 is an insulating resin such as an epoxy resin.

  A control circuit 39 that controls the drive circuit 34 by being electrically connected to the drive circuit 34 is mounted on the non-facing surface 31 b of the substrate 31. That is, the substrate 31 is a composite circuit board in which the drive circuit 34 of the motor 15 and the control circuit 39 of the drive circuit 34 are mounted on the upper and lower surfaces (opposing surface 31a and non-facing surface 31b) of the common substrate 31. is there. The control circuit 39 includes a microcomputer 40 that executes a predetermined operation program stored in the memory.

  The drive circuit 34 and the control circuit 39 mounted on the substrate 31 constitute a part of the ECU 48. In the ECU 48, the control circuit 39 controls the drive circuit 34 to turn on / off the plurality of switching elements 36, thereby outputting a signal for driving the motor 15 to the motor bus bar 21 from the drive circuit 34. The signal output to the motor bus bar 21 is transmitted to the stator 16. As a result, the motor 15 is driven in a sine wave.

  Between the heat sink 10 and the substrate 31, a magnetic shielding member 42 containing a magnetic material and a sealing resin 51 for sealing the magnetic sensor 32 are provided. Hereinafter, specific configurations of the magnetic shielding member 42 and the sealing resin 51 will be described with reference to FIGS. 2 and 3. FIG. 2 is an enlarged cross-sectional view showing the main parts of the magnetic shielding member 42 and the sealing resin 51 of FIG. FIG. 3 is a cross-sectional view taken along the line III-III shown in FIG. In FIG. 3, the sealing resin 51 is not shown.

  2 and 3, the magnetic shielding member 42 has a cylindrical shape and is disposed so as to surround the periphery of the permanent magnet 30 and the magnetic sensor 32 in plan view. That is, the magnetic shielding member 42 has an inner wall 42 a that defines the sensor mounting region 33 and an outer wall 42 b that partitions the drive circuit mounting region 35. Hereinafter, the space surrounded by the magnetic shielding member 42 is simply referred to as a sensor mounting region 33, and the space outside the magnetic shielding member 42 is simply referred to as a drive circuit mounting region 35.

  The magnetic shielding member 42 magnetically shields the sensor mounting area 33 and the drive circuit mounting area 35. More specifically, the magnetic shielding member 42 shields the magnetic path connecting the permanent magnet 30 and the drive circuit 34 mounted on the substrate 31, and between the magnetic sensor 32 and the drive circuit 34. The magnetic path connecting the two is shielded. The height T of the magnetic shielding member 42 from the second main surface 10b of the heat sink 10 is, for example, about 5 mm. In the present embodiment, the magnetic shielding member 42 is illustrated as being formed in a substantially cylindrical shape, but the magnetic shielding member 42 may be in a substantially rectangular tube shape.

  More specifically, the magnetic shielding member 42 has a substantially cylindrical main body 43 and a plating film 44 formed so as to cover the main body 43. In the present embodiment, the main body 43 is integrated with the heat sink 10 and is made of the same material (aluminum) as the heat sink 10. The plating film 44 is formed so as to cover the entire surface of the main body 43. The plating film 44 is a plating film made of a ferromagnetic material such as nickel (Ni). The magnetic shielding member 42 has a heat radiating plate side end portion 42c located on the heat radiating plate 10 side and a substrate side end portion 42d located on the substrate 31 side. The heat dissipation plate side end portion 42 c of the magnetic shielding member 42 is integrated with the heat dissipation plate 10 by the main body portion 43 described above, and the substrate side end portion 42 d of the magnetic shielding member 42 is in contact with the substrate 31.

  Referring to FIG. 2, an engagement portion 45 that engages with the substrate-side end portion 42 d of the magnetic shielding member 42 is formed on the substrate 31. In the present embodiment, the engaging portion 45 is a concave portion 46 formed in a substantially annular shape in plan view so as to be fitted to the substrate side end portion 42 d of the magnetic shielding member 42. On the substrate 31, a ground wiring 47 for providing a ground potential (reference voltage) to the drive circuit 34 and / or the control circuit 39 is formed. The ground wiring 47 is made of, for example, copper foil. The recess 46 (engagement portion 45) is formed on the substrate 31 so that a part of the ground wiring 47 is exposed. A substrate-side end portion 42 d of the magnetic shielding member 42 is fitted (engaged) with a recess 46 (engagement portion 45) formed in the substrate 31. The substrate-side end portion 42d of the magnetic shielding member 42 is electrically connected to the ground wiring 47 in the recess 46 (engagement portion 45).

  With reference to FIG. 2, the sealing resin 51 is formed on the substrate 31 so as to seal the entire area of the magnetic sensor 32. That is, the sealing resin 51 covers the upper surface (opposing surface facing the permanent magnet 30) and side surfaces of the magnetic sensor 32. The sealing resin 51 is formed at a distance from the permanent magnet 30. The sealing resin 51 is a resin containing a powdery magnetic material. Examples of the magnetic material of the sealing resin 51 include one or more magnetic species selected from the group including iron (Fe), nickel (Ni), and cobalt (Co). An example of the sealing resin 51 is an epoxy resin.

  The sealing resin 51 is formed in a substantially cylindrical shape so as to be fitted to the inner wall 42 a of the magnetic shielding member 42, the facing surface 52 a facing the heat sink 10 and the permanent magnet 30, and the inner wall 42 a of the magnetic shielding member 42. And a side surface 52b opposite to each other. The facing surface 52a of the sealing resin 51 is formed in a concave shape whose central portion is smoothly recessed toward the substrate 31 side. The facing surface 52 a of the sealing resin 51 faces the entire plate surface 30 b of the permanent magnet 30 in the axial direction of the shaft 18. Furthermore, the peripheral edge portion of the facing surface 52 a of the sealing resin 51 faces part or all of the side surface of the permanent magnet 30 in the direction orthogonal to the axial direction of the shaft 18. FIG. 2 shows an example in which the peripheral portion of the facing surface 52 a of the sealing resin 51 is opposed to the entire side surface of the permanent magnet 30.

  The side surface 52 b of the sealing resin 51 may be in contact with the inner wall 42 a of the magnetic shielding member 42. In this case, since the positioning accuracy of the magnetic sensor 32 with respect to the permanent magnet 30 is improved, the rotation angle detection accuracy by the magnetic sensor 32 can be improved. The side surface 52b of the sealing resin 51 may not be in contact with the inner wall 42a of the magnetic shielding member 42 but may be opposed to the inner wall 42a of the magnetic shielding member 42 with a gap. In this case, since air having a relatively high magnetic resistance is interposed between the sealing resin 51 and the magnetic shielding member 42, the effect of suppressing the leakage of the magnetism of the permanent magnet 30 outside the magnetic shielding member 42 is enhanced. In addition, the rotation angle detection accuracy by the magnetic sensor 32 can be improved. Of course, the side surface 52b of the sealing resin 51 may include a part in contact with the inner wall 42a of the magnetic shielding member 42 and a part facing the inner wall 42a of the magnetic shielding member 42 with a space therebetween. .

Referring again to FIG. 1, a bottomed cylindrical cover member 50 having an opening 50 a on the motor housing 2 side is attached to the heat sink 10 so as to accommodate the substrate 31 between the heat sink 10. It has been.
As described above, in the present embodiment, since the magnetic path connecting the magnetic sensor 32 and the drive circuit 34 can be shielded by the magnetic shielding member 42, it is possible to suppress electromagnetic noise generated on the drive circuit 34 side from reaching the magnetic sensor 32. . In particular, in the present embodiment, electromagnetic noise generated in the motor bus bar 21, the plurality of switching elements 36, and the like through which a relatively large current (for example, about 100 A) flows can be shielded by the magnetic shielding member 42. Thereby, it can suppress that the electromagnetic noise generated on the drive circuit 34 side is detected by the magnetic sensor 32.

  Furthermore, in this embodiment, the magnetic sensor 32 is sealed with a sealing resin 51 containing a magnetic material. Thereby, since the magnetic resistance between the permanent magnet 30 and the magnetic sensor 32 can be reduced, the magnetism from the permanent magnet 30 can be satisfactorily detected by the magnetic sensor 32. As a result, since the magnetism from the permanent magnet 30 can be satisfactorily detected by the magnetic sensor 32, the rotation angle detection accuracy of the magnetic sensor 32 can be improved.

  In the present embodiment, the sealing resin 51 has a concave facing surface 52a whose central portion is recessed toward the substrate 31 side. Thereby, the permanent magnet 30 and the magnetic sensor 32 can be disposed close to each other while increasing the ratio of the sealing resin 51 occupying the space surrounded by the magnetic shielding member 42 (that is, the sensor mounting region 33). As a result, the rotation angle detection accuracy of the magnetic sensor 32 can be further improved.

  Further, in the present embodiment, since the adverse effect due to electromagnetic noise generated on the substrate 31 can be reduced by the magnetic shielding member 42, the permanent magnet 30 and the substrate 31 (the drive circuit 34 and the control circuit 39) can be disposed relatively close to each other. As a result, the integrated motor / ECU 101 can be reduced in size and cost. In particular, in the present embodiment, the configuration in which the drive circuit 34 and the control circuit 39 are mounted on the upper and lower surfaces of the common substrate 31 is adopted, which can further contribute to the downsizing and cost reduction of the integrated motor / ECU 101. .

  In the present embodiment, the sealing resin 51 is formed on the substrate 31 so as to be fitted to the inner wall 42 a of the magnetic shielding member 42. In addition, in the present embodiment, the substrate 31 is formed with a recess 46 (engagement portion 45) that fits (engages) with the substrate-side end portion 42 d of the magnetic shielding member 42. Thereby, since the precision of positioning of the board | substrate 31 with respect to the heat sink 10 improves, the precision of positioning with the permanent magnet 30 and the magnetic sensor 32 can be improved. As a result, the rotation angle detection accuracy of the magnetic sensor 32 can be further improved.

  Further, in the present embodiment, a second bearing holding portion 12 (recess) for holding the second bearing 11 is formed on the first main surface 10 a of the heat radiating plate 10. Thereby, since the positioning accuracy of the shaft 18 with respect to the heat sink 10 is improved, the positioning accuracy between the permanent magnet 30 attached to the shaft 18 and the magnetic sensor 32 on the substrate 31 can be improved. As a result, the rotation angle detection accuracy of the magnetic sensor 32 can be further improved.

  Further, the substrate-side end portion 42d of the magnetic shielding member 42 is electrically connected to the ground wiring 47 in the recess 46 (engagement portion 45). Thereby, since the ground wiring 47 formed on the substrate 31 and the heat sink 10 can be electrically connected via the magnetic shielding member 42, the wiring area of the ground wiring 47 can be increased. As a result, the stability of the ground potential can be improved, so that noise generated in the drive circuit 34 and the control circuit 39 can be reduced.

As mentioned above, although embodiment of this invention was described, this invention can also be implemented with another form.
For example, the permanent magnet 30, the sealing resin 38, and the sealing resin 51 in the above-described embodiment may take various forms as shown in FIG. FIG. 4 is an enlarged cross-sectional view showing a main part of a rotation angle detection device 60 according to a modification. In addition, each structure of the rotation angle detection apparatus 60 is not limited to the structure shown in FIG. 4, It can combine with each structure to which the rotation angle detection apparatus 1 respond | corresponds individually.

  In the above-described embodiment, the example in which the permanent magnet 30 is exposed has been described. However, as shown in FIG. 4, a sealing resin 61 similar to the sealing resin 51 may be provided so as to seal the surface of the permanent magnet 30. Even with such a configuration, since the ratio of the sealing resin (the sealing resin 51 and the sealing resin 61) occupying the sensor mounting region 33 can be increased, the rotation angle detection accuracy by the magnetic sensor 32 can be improved.

  In the above-described embodiment, the example in which the sealing resin 51 has the facing surface 52a formed in a smooth concave shape has been described. However, as shown in FIG. 4, the sealing resin 51 seals the magnetic sensor 32, and the substantially cylindrical main body 62 facing the plate surface 30 b of the permanent magnet 30, and the edge of the main body 62 (see FIG. 4). 4 (see the broken line portion 4), and a substantially cylindrical tube portion 63 extending toward the heat radiating plate 10 may be integrally provided. The main body 62 has a surface parallel to the plate surface 30 b of the permanent magnet 30. The cylindrical portion 63 is provided along the inner wall 42 a of the magnetic shielding member 42, and is in contact with the second main surface 10 b of the heat sink 10. The cylindrical portion 63 faces the entire side surface of the permanent magnet 30. The cylinder part 63 may be provided separately from the second main surface 10 b of the heat sink 10 so as to face a part of the side surface of the permanent magnet 30.

  In this example, the sealing resin 51 is formed in a substantially cylindrical shape by the main body portion 62 and the cylindrical portion 63. The sealing resin 51 includes a concave facing surface 52 a that is formed by the main body portion 62 and the cylindrical portion 63 and faces the heat sink 10 and the permanent magnet 30, and a side surface 52 b that is in contact with the inner wall 42 a of the magnetic shielding member 42. Have. Even with such a configuration, since the ratio of the sealing resin 51 occupying the sensor mounting region 33 can be increased, the rotation angle detection accuracy by the magnetic sensor 32 can be improved. Of course, the sealing resin 51 may include only the substantially cylindrical main body 62. Further, the sealing resin 51 may be formed in an annular shape so as to seal only the side surface of the magnetic sensor 32. That is, the upper surface of the magnetic sensor 32 may be exposed from the sealing resin 51.

  In the above-described embodiment, the example in which the switching element 36 and the heat dissipation member 37 are sealed with the sealing resin 38 has been described. As shown in FIG. 4, the sealing resin 38 may be formed in a substantially annular shape so as to be in contact with the outer wall 42 b of the magnetic shielding member 42. That is, the sealing resin 38 may be formed so that its inner peripheral surface 38 a is fitted to the outer wall 42 b of the magnetic shielding member 42. According to this configuration, the inner wall 42 a and the outer wall 42 b of the magnetic shielding member 42 can be sandwiched by the sealing resin 51 and the sealing resin 38 from both the sensor mounting region 33 and the drive circuit mounting region 35. Thereby, the precision of positioning of the board | substrate 31 with respect to the heat sink 10 can be improved further.

  In the above-described embodiment, the example in which the drive circuit 34 is mounted on the facing surface 31 a of the substrate 31 and the control circuit 39 is mounted on the non-facing surface 31 b of the substrate 31 has been described. However, the drive circuit 34 may be mounted on the non-facing surface 31 b of the substrate 31 and the control circuit 39 may be mounted on the facing surface 31 a of the substrate 31. According to this configuration, the magnetic shielding member 42 can shield the magnetic path connecting the control circuit 39 and the permanent magnet 30 and can shield the magnetic path connecting the control circuit 39 and the magnetic sensor 32. Further, the drive circuit 34 and the control circuit 39 may be formed on different substrates. That is, one of the drive circuit 34 and the control circuit 39 may be mounted on the substrate 31.

In the above-described embodiment, the example in which the magnetic shielding member 42 is formed integrally with the heat radiating plate 10 has been described. However, a separate magnetic shielding member 42 from the heat radiating plate 10 may be provided. In this case, the magnetic shielding member 42 may be formed of a ferromagnetic material such as nickel.
In the above-described embodiment, the example in which the magnetic shielding member 42 includes the plating film 44 has been described. The plating film 44 may be formed on at least one of the inner wall and the outer wall of the main body 43 of the magnetic shielding member 42. Further, the plating film 44 is formed on at least one of the inner wall and the outer wall of the main body 43 of the magnetic shielding member 42 so as to expose a portion that fits (engages) in the recess 46 (engaging portion 45) of the substrate 31. May be. Further, the plating film 44 may be formed so as to cover a partial region or the entire region of the second main surface 10 b of the heat sink 10. According to this configuration, a partial region or the entire region of the second main surface 10b of the heat sink 10 can be used as a magnetic shielding member.

In the above-described embodiment, the example in which the magnetic shielding member 42 is electrically connected to the ground wiring 47 formed on the substrate 31 has been described. However, the magnetic shielding member 42 may be thermally connected to the substrate 31 and the heat sink 10 by being connected to a metal film for heat dissipation formed on the substrate 31. Of course, the ground wiring 47 may also serve as a metal film for heat dissipation.
In the above-described embodiment, the example in which the ground wiring 47 is formed so as to be exposed from the concave portion 46 (engagement portion 45) of the substrate 31 has been described. However, the ground wiring 47 may be formed on the non-facing surface 31 b of the substrate 31. In this case, the substrate-side end portion 42d of the magnetic shielding member 42 is connected to the ground wiring on the non-facing surface 31b of the substrate 31 through a via formed through the substrate 31 in the recess 46 (engagement portion 45). 47 may be electrically connected. According to this configuration, after forming the recess 46 (engagement portion 45) on the facing surface 31 a of the substrate 31, a via penetrating the substrate 31 is formed, and the via is covered on the non-facing surface 31 b of the substrate 31. Since the ground wiring 47 may be formed, it is easy to manufacture.

  In addition, various design changes can be made within the scope of matters described in the claims.

  DESCRIPTION OF SYMBOLS 1 ... Rotation angle detection apparatus, 10 ... Heat sink, 15 ... Motor, 18 ... Shaft (rotary shaft), 18b ... Base end part (one end part) of a shaft, 30 ... Permanent magnet, 31 ... Substrate, 32 ... Magnetic sensor ( Magnetic sensing element), 34 ... Drive circuit, 39 ... Control circuit, 42 ... Magnetic shielding member, 42a ... Inner wall of magnetic shielding member, 43 ... Main body of magnetic shielding member, 51 ... Sealing resin, 52 ... Sealing resin Opposite surface (surface)

Claims (4)

A rotation angle detection device for detecting a rotation angle of a motor having a rotation shaft penetrating a metal plate,
A permanent magnet attached to one end of the rotating shaft passing through the metal plate;
A substrate on which the motor drive circuit is mounted, facing the metal plate on the side opposite to the metal plate with respect to the permanent magnet,
A magnetically sensitive element provided on the substrate to face the permanent magnet;
Between the metal plate and the substrate, a cylindrical magnetic shielding member disposed so as to surround the permanent magnet in plan view,
A rotation angle detecting device including a magnetic material and a sealing resin formed on the substrate so as to seal at least a part of the magnetically sensitive element. The magnetic shielding member is provided integrally with the metal plate,
The rotation angle detection device according to claim 1, wherein the sealing resin is formed on the substrate so as to be fitted to an inner wall of the magnetic shielding member.   The said sealing resin is formed on the said board | substrate so that the whole region of the said magnetic sensitive element may be sealed, and has the concave surface dented toward the said board | substrate side. The rotation angle detection device described. The magnetic shielding member is
A cylindrical main body having an inner wall and an outer wall;
The rotation angle detection device according to any one of claims 1 to 3, further comprising: a plating layer including a magnetic material formed on at least one of an inner wall and an outer wall of the main body.

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