WO2020166344A1

WO2020166344A1 - Motor device

Info

Publication number: WO2020166344A1
Application number: PCT/JP2020/003312
Authority: WO
Inventors: 裕人佐藤
Original assignee: 株式会社ジェイテクト
Priority date: 2019-02-14
Filing date: 2020-01-30
Publication date: 2020-08-20

Abstract

A motor device is provided with: a motor having a rotating shaft; a control device configured so as to control operation of the motor; and a rotation angle sensor configured so as to detect the rotation angle of the rotating shaft. The control device comprises a power substrate and a control substrate. The power substrate and the control substrate are arranged side by side in the axial direction of the rotating shaft, and the power substrate is arranged between the control substrate and one end of the rotating shaft in the axial direction of the rotating shaft. The rotation angle sensor comprises a sensor magnet provided to the one end of the rotating shaft and a magnetic detection element provided to the power substrate so as to face the sensor magnet.

Description

Motor device

The present disclosure relates to a motor device.

As described in Patent Document 1, there is a motor device that includes a motor and a control device that controls the motor. The control device has a power board and a control board. The power board is provided with a power element that controls the current supplied to the motor. The control board is provided with a microcomputer that controls driving of the power element. The motor device has a rotation angle sensor for detecting the rotation angle of the rotation shaft of the motor. The rotation angle sensor has a sensor magnet provided at the tip of the rotation shaft of the motor and a magnetic detection element that generates an electric signal according to a change in the magnetic field. The magnetic detection element is provided on the control board. The microcomputer calculates the rotation angle of the rotation shaft of the motor based on the electric signal generated by the magnetic detection element. The microcomputer controls energization to the motor coil by controlling on/off of the power element based on the rotation angle.

JP, 2011-177001, A

In a motor device with a built-in control device, there is a magnetic flux source in addition to the sensor magnet. As the magnetic flux source, for example, a power substrate can be cited. Since a large current flows through the power board when the motor coil is energized, the magnetic field generated due to the current flow tends to become large. When a magnetic field generated by the power board is applied to the magnetic detection element in addition to the magnetic field generated by the sensor magnet, the rotation angle of the motor rotation axis calculated based on the electrical signal generated by the magnetic detection element and the actual rotation. There is concern that the error between the corners will increase.

A motor device according to an aspect of the present disclosure includes a motor having a rotation shaft, a control device configured to control operation of the motor, and a rotation angle configured to detect a rotation angle of the rotation shaft. And a sensor. The control device includes a power board provided with a power element configured to control a current supplied to the motor, and a microcomputer configured to control driving of the power element. And a control board. The power board and the control board are arranged side by side in the axial direction of the rotation axis with respect to the rotation axis, and the power board is arranged in the axial direction of the rotation axis such that one end of the rotation axis and the control board. It is located between. The rotation angle sensor includes a sensor magnet and a magnetic detection element configured to generate an electric signal according to an applied magnetic field. The sensor magnet is provided at the one end of the rotary shaft, and the magnetic detection element is provided at the surface of the power substrate facing the one end of the rotary shaft so as to face the sensor magnet. There is.

The perspective view of the motor device of this embodiment. The disassembled perspective view of the motor apparatus of FIG. Sectional drawing of the motor apparatus of FIG. FIG. 6 is a schematic cross-sectional view showing a peripheral structure of a magnetic detection element in a motor device of a comparative example. FIG. 2 is a schematic cross-sectional view showing a peripheral structure of a magnetic detection element in the motor device of FIG. 1.

An embodiment of a motor device will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the motor device 1 includes a motor 2 having a rotating shaft 41 and a control device 3 for controlling the operation of the motor 2. A plurality of electronic components are mounted on the control device 3. The control device 3 has a power board 4 and a control board 5. The motor device 1 also includes an external connection portion 6 for connecting to an external device, a cylindrical motor housing 7 that houses the motor 2, and a cover 8. The cover 8 is attached to one end of the motor housing 7.

Hereinafter, for convenience of explanation, in the axial direction X of the rotary shaft 41, the side where the cover 8 is located with respect to the motor 2 is the axial first side, and the side where the motor 2 is located with respect to the cover 8 is the axial second side. Side. The axial direction X is a direction in which the rotating shaft 41 extends. The rotating shaft 41 has a first end on the first axial side and a second end on the second axial side. The motor device 1 is mounted on, for example, an electric power steering device of a vehicle.

The configuration of the motor 2 and the motor housing 7 will be described.

As shown in FIG. 3, the motor 2 includes a stator 11 fixed in the motor housing 7 and a rotor 12 rotatably arranged with respect to the stator 11.

As shown in FIGS. 2 and 3, the motor housing 7 has a tubular housing body 21 having an open end 21a and a closed end, and a flat end plate 22. The end plate 22 is attached to the opening end 21a so as to close the opening of the housing body 21. The end plate 22 functions as a heat sink for radiating the heat generated by the motor device 1 to the outside.

A first insertion hole 23 penetrating in the axial direction X is formed in the center of the end wall existing at the closed end of the housing body 21. A second insertion hole 24 is formed at the center of the end plate 22 so as to penetrate in the axial direction X. The second insertion hole 24 has a first hole 24a, a second hole 24b, and a third hole 24c in order from the second axial side toward the first axial side. The inner diameter of the first hole 24a and the inner diameter of the third hole 24c are larger than the inner diameter of the second hole 24b. The open end 21a of the housing body 21 has a substantially circular shape. A plurality of engaging projections 25 are formed on the outer peripheral surface of the opening end 21a. The end plate 22 is formed with a plurality of support portions 26 that protrude toward the first side in the axial direction.

The stator 11 includes a cylindrical stator core 31 and a motor coil 32 wound around the stator core 31. The stator core 31 is fixed inside the peripheral wall of the housing body 21. The connection terminal 32 a of the motor coil 32 is connected to the bus bar 33. The bus bar 33 extends in the axial direction X from the external connection portion 6 to the motor coil 32.

The rotor 12 includes a cylindrical rotor core 42 and a plurality of permanent magnets 43 fixed to the outer circumference of the rotor core 42. The rotor core 42 is fixed to the rotating shaft 41 so as to rotate integrally with the rotating shaft 41. The permanent magnets 43 are arranged so that the N poles and the S poles are alternated in the circumferential direction of the rotor core 42. A first bearing 44 is provided in the first insertion hole 23. The first bearing 44 rotatably supports the second end of the rotating shaft 41. A second bearing 45 is provided in the first hole 24a of the second insertion hole 24. The second bearing 45 rotatably supports the first end of the rotating shaft 41. As a result, the rotary shaft 41 is rotatably supported by the inner surface of the motor housing 7 via the first bearing 44 and the second bearing 45. The first end of the rotary shaft 41, that is, the end facing the power board 4 does not protrude from the second insertion hole 24 beyond the motor housing 7 (specifically, the end plate 22) to the first axial side.

The motor device 1 has a rotation angle sensor 70 for detecting the rotation angle of the rotation shaft 41. The rotation angle sensor 70 has a sensor magnet 71 and a magnetic detection element 72. The sensor magnet 71 is provided in a portion of the rotating shaft 41 closer to the power board 4 than a portion to which the rotor core 42 is fixed. In the present embodiment, the sensor magnet 71 is provided on the end surface of the first end portion of the rotating shaft 41, that is, the end surface facing the power board 4. As the sensor magnet 71, for example, a columnar two-pole magnet is adopted. The outer diameter of the sensor magnet 71 is set to be larger than the outer diameter of the first end portion of the rotating shaft 41. The outer diameter of the sensor magnet 71 is set smaller than the inner diameter of the third hole 24c. The sensor magnet 71 is arranged at the same position as the third hole 24c in the axial direction X, that is, located in the third hole 24c. The magnetic detection element 72 is provided on the power board 4.

The power board 4 and the control board 5 will be described.

The power board 4 and the control board 5 are arranged side by side in the axial direction X with respect to the rotating shaft 41. In the axial direction X of the rotating shaft 41, the power board 4 and the control board 5 are arranged side by side in the order closer to the rotating shaft 41. That is, in the axial direction X of the rotary shaft 41, the power board 4 is arranged between the first end portion of the rotary shaft 41 and the control board 5. The power board 4 and the control board 5 are each formed in a substantially disc shape corresponding to the shape of the cover 8. The power board 4 and the control board 5 are arranged so that the thickness directions of the power board 4 and the control board 5 coincide with the axial direction X, respectively.

The power board 4 is provided with electronic components 100 such as a power element 101 and a magnetic detection element 72. For the power element 101, for example, a FET (field effect transistor) is adopted. The power element 101 is connected to the connection terminal 32 a of the motor coil 32 via the bus bar 33. The power element 101 controls the current supplied to the motor coil 32 via the bus bar 33.

The magnetic detection element 72 is provided on the surface of the power substrate 4 that faces the first end of the rotating shaft 41. The magnetic detection element 72 faces the sensor magnet 71 in the axial direction X. The magnetic detection element 72 is provided at a portion of the power board 4 that intersects with the axis of the rotating shaft 41. For example, a Hall element is adopted as the magnetic detection element 72. The magnetic detection element 72 detects a component of the applied magnetic field in a direction orthogonal to the axial direction X. The magnetic detection element 72 generates an electric signal according to the applied magnetic field.

Other electronic components such as the power element 101 are provided in a portion other than a portion of the power board 4 that intersects with the axis of the rotating shaft 41, for example, in a peripheral portion of the power board 4. A plurality of terminal holes 102 are formed in the peripheral portion of the power board 4.

The control board 5 is provided with an electronic component 110 such as a microcomputer 111 that controls driving of the power element 101. The microcomputer 111 is provided on the surface of the control board 5 opposite to the rotary shaft 41. The microcomputer 111 is provided in a portion of the control board 5 that intersects with the axis of the rotating shaft 41. A plurality of terminal holes 112 are formed in the peripheral portion of the control board 5.

A connector 120 that connects the control board 5 and the power board 4 to each other is provided on the surface of the control board 5 that faces the power board 4. The connector 120 has a first connection line 121 and a second connection line 122. The first connection line 121 connects the power element 101 and the microcomputer 111 to each other. The second connection line 122 connects the magnetic detection element 72 and the microcomputer 111 to each other.

The ends of the first connecting line 121 and the second connecting line 122 on the first side in the axial direction are soldered to the control board 5 while being inserted into the terminal holes 112 of the control board 5. The ends of the first connecting line 121 and the second connecting line 122 on the second side in the axial direction are soldered to the power board 4 while being inserted into the terminal holes 102 of the power board 4. As a result, the control board 5 and the power board 4 are connected to each other.

The microcomputer 111 acquires the electric signal generated by the magnetic detection element 72 via the second connection line 122. The microcomputer 111 calculates the rotation angle of the rotation shaft 41 of the motor 2 based on the electric signal. The microcomputer 111 generates a control signal for controlling the operation of the motor 2 based on the calculated rotation angle. The microcomputer 111 outputs the control signal to the power element 101 via the first connection line 121. The power element 101 is turned on/off based on the control signal. The microcomputer 111 controls the current supplied to the motor coil 32 via the bus bar 33 by turning on/off the power element 101. As a result, a rotating magnetic field is generated in the stator 11, and the rotor 12 rotates based on the rotating magnetic field.

The external connection portion 6 has a main body portion 51 and a plurality of protruding portions 52 that protrude from the main body portion 51 in the first axial direction. The main body 51 is formed in a substantially disc shape when viewed in the axial direction X. Each protrusion 52 is formed in a substantially rectangular tube shape. Wirings extending from devices outside the motor device 1 can be connected to the respective protrusions 52. The main body 51 is fixed to the control board 5. With the external connection portion 6 fixed to the control board 5, the connection terminals arranged in the protruding portion 52 are connected to predetermined positions on the power board 4 and the control board 5.

Explain the structure of the cover 8.

The cover 8 has a shape corresponding to the shape of the open end 21a of the housing body 21, and is attached to the open end 21a. The cover 8 houses the power board 4 and the control board 5. The cover 8 has a cylindrical peripheral wall 61 and an end wall 62. On the peripheral wall 61, plate-shaped mounting portions 63 that project to the second side in the axial direction are formed at a plurality of locations. An engaging hole 64 is formed in each mounting portion 63 so as to penetrate the mounting portion 63 in the plate thickness direction.

The end wall 62 is formed with a through hole 65 penetrating the end wall 62 in the axial direction X. The cover 8 is mounted on the motor housing 7 by engaging the engagement protrusion 25 with the engagement hole 64 of the mounting portion 63 in a state where the protrusion 52 protrudes from the cover 8 through the through hole 65. There is.

The operation and effect of this embodiment will be described.

(1) In addition to the magnetic field generated by the sensor magnet 71, the magnetic field generated by the power substrate 4 may be applied to the magnetic detection element 72. Since a large current flows through the power board 4 when the motor coil 32 is energized, the magnetic field generated in the power board 4 tends to increase due to the current flow. The magnetic field applied from the power substrate 4 to the magnetic detection element 72 is a magnetic field generated by a large current flowing through the power substrate 4, and is not a magnetic field that the magnetic detection element 72 should originally detect.

For example, consider the configuration shown in FIG. 4 as a comparative example. In this comparative example, a magnetic detection element 72 is provided on the control board 5, and a sensor magnet 71 is provided at the end of the rotary shaft 41. Then, the rotating shaft 41 is inserted into the through hole formed in the power substrate 4, so that the magnetic detection element 72 and the sensor magnet 71 are opposed to each other.

When a large current flows through the wiring P along the surface of the power board 4, a magnetic field is formed around the wiring P as a center. Among the magnetic fields applied from the power substrate 4 to the magnetic detection element 72, the direction of the magnetic field near the magnetic detection element 72 and the direction in which the surface of the power substrate 4 extends form an angle θ1. The vicinity of the magnetic detection element 72 is, for example, a specific point P2 in a portion of the magnetic detection element 72 that contacts the control substrate 5.

As an example, the angle θ1 is an angle formed by the tangential direction at the point P2 of the magnetic field applied from the power substrate 4 to the magnetic detection element 72 and the direction in which the surface of the control substrate 5 extends. The absolute value of the angle θ1 becomes smaller as the power substrate 4 as the magnetic field generation source and the magnetic detection element 72 are separated from each other in the axial direction X of the rotation shaft 41. That is, the component of the magnetic field applied from the power substrate 4 to the magnetic detection element 72 in the direction orthogonal to the axial direction X tends to increase as the power substrate 4 and the magnetic detection element 72 move away from each other in the axial direction X.

As in the comparative example, when the magnetic detection element 72 is provided on the control board 5 which is arranged apart from the power board 4 in the axial direction X, the magnetic detection element 72 is provided between the power board 4 and the control board 5 in the axial direction X. It is separated from the power board 4 by a distance therebetween. Therefore, the detection amount of the magnetic field from the power board 4 detected by the magnetic detection element 72 must be correspondingly large.

In the present embodiment, as shown in FIG. 5, the magnetic detection element 72 is provided on the power board 4. Here, when a large current flows in the wiring P along the surface of the power substrate 4, the strength of the magnetic field applied from the power substrate 4 to the magnetic detection element 72 is different between the case of this embodiment and the case of the comparative example. And the same. Among the magnetic fields applied from the power board 4 to the magnetic detection element 72, the direction of the magnetic field in the vicinity of the magnetic detection element 72 and the direction in which the surface of the power board 4 extends have an absolute value larger than the angle θ1. It forms an angle θ2.

As an example, the angle θ2 is an angle formed by the tangential direction at the point P2 of the magnetic field applied from the power board 4 to the magnetic detection element 72 and the direction in which the surface of the power board 4 extends. Therefore, the component of the magnetic field applied from the power substrate 4 to the magnetic detection element 72 in the direction orthogonal to the axial direction X is smaller than that in the comparative example. This is because the angle θ2 is an angle whose absolute value is larger than the angle θ1. Therefore, the cosine component of the magnetic field applied from the power substrate 4 to the magnetic detection element 72 is larger in the case of this embodiment than in the case of the comparative example. This is because it becomes smaller.

As described above, in the present embodiment, since the power board 4 and the magnetic detection element 72 are not separated from each other in the axial direction X, the detection amount of the magnetic field from the power board 4 detected by the magnetic detection element 72 is set as a comparative example. It can be smaller than the case. Thereby, it is possible to suppress the influence of the magnetic field from the power substrate 4 from being included in the electric signal generated by the magnetic detection element 72. From this, it is possible to suppress an increase in the error between the rotation angle of the rotation shaft 41 calculated by the magnetic detection element 72 and the actual rotation angle, and to improve the detection accuracy of the rotation angle of the rotation shaft 41. ..

(2) The same connector 120 has a first connection line 121 and a second connection line 122 that connect the power board 4 and the control board 5 to each other. Therefore, the number of connectors can be reduced as compared with the case where separate connectors have the first connection line 121 and the second connection line 122. Accordingly, the connector that connects the power board 4 and the control board 5 can be simply configured.

(3) The rotating shaft 41 is rotatably supported by the first bearing 44 and the second bearing 45 with respect to the inner surface of the motor housing 7. The rotary shaft 41 swings in a direction orthogonal to the axial direction X as the first end of the rotary shaft 41 moves away from the second bearing 45, in other words, as the first end of the rotary shaft 41 projects from the second bearing 45. Easier to do. When the first end of the rotating shaft 41 swings, the sensor magnet 71 provided at the first end also swings, so that the magnetic field applied from the sensor magnet 71 to the magnetic detection element 72 changes. Will end up. According to this embodiment, the first end of the rotary shaft 41 does not project beyond the motor housing 7. That is, since the amount of the first end of the rotary shaft 41 protruding from the second bearing 45 is suppressed, the first end and the sensor magnet 71 provided at the first end may swing. Can be suppressed. Thereby, the magnetic field applied to the magnetic detection element 72 can be stabilized. Therefore, it is possible to suppress an increase in error between the rotation angle of the rotation shaft 41 calculated through the magnetic detection element 72 and the actual rotation angle, and it is possible to further improve the detection accuracy of the rotation angle of the rotation shaft 41.

(4) According to the present embodiment, since it is not necessary to secure a space for disposing the magnetic detection element 72 on the control board 5, the degree of freedom in disposing the electronic component 110 such as the microcomputer 111 on the control board 5. Can be increased. Therefore, the microcomputer 111 can be arranged at the portion of the control board 5 that intersects the axis of the rotating shaft 41.

Note that this embodiment may be modified as follows. Further, the following other embodiments can be combined with each other within a technically consistent range.

The magnetic detection element 72 may be a magnetoresistive effect element instead of the hall element.

The microcomputer 111 may not be provided in a portion of the control board 5 that intersects with the axis of the rotating shaft 41.

The first end of the rotary shaft 41 of the motor 2 may protrude from the second insertion hole 24 of the motor housing 7 beyond the motor housing 7.

-One connector 120 has the first connection line 121 and the second connection line 122, but different connectors may have the first connection line 121 and the second connection line 122, respectively. For example, the connector having the first connection line 121 and the connector having the second connection line may be separate connectors.

-The external connection part 6 may have the function of the cover 8 without providing the cover 8. That is, the external connection portion 6 is assembled to one end portion of the motor housing 7 (open end 21 a of the housing body 21 ), and the power board 4 and the control board 5 are provided in the internal space formed by the external connection portion 6 and the motor housing 7. May be accommodated.

The motor 2 and the control device 3 may be redundantly provided. That is, two systems of the magnetic detection element 72 are provided on the power board 4, and two systems of the electronic component 100 such as the power element 101 are provided. Further, the control board 5 is provided with two systems of the electronic component 110 such as the microcomputer 111, and two systems of the first connection line 121 and the second connection line 122 of the connector 120 are also provided. As described above, even when the motor 2, the control device 3, and the magnetic detection element 72 are redundantly provided, the magnetic detection can be performed by providing the two-system magnetic detection elements 72 on the power board 4 that is a magnetic flux generation source. The detection amount of the magnetic field from the power board 4 detected by the element 72 can be reduced.

-Although the shapes of the power board 4 and the control board 5 are substantially disk-shaped, these shapes can be changed as appropriate.

The motor device 1 is not limited to being mounted on the electric power steering device of the vehicle, but may be mounted on, for example, a driving device that drives the wheels of the vehicle.

Claims

A motor device comprising a motor having a rotation shaft, a control device configured to control operation of the motor, and a rotation angle sensor configured to detect a rotation angle of the rotation shaft,
The control device is
A power board provided with a power element configured to control a current supplied to the motor;
A control board provided with a microcomputer configured to control the drive of the power element,
The power board and the control board are arranged side by side in the axial direction of the rotating shaft with respect to the rotating shaft,
In the axial direction of the rotating shaft, the power board is arranged between one end of the rotating shaft and the control board,
The rotation angle sensor is
A sensor magnet,
A magnetic detection element configured to generate an electric signal in response to an applied magnetic field,
The sensor magnet is provided at the one end of the rotary shaft,
A motor device in which the magnetic detection element is provided to face the sensor magnet on a surface of the power substrate that faces the one end of the rotary shaft.
Further comprising a connector connecting the power board and the control board to each other,
The connector is
A first connection line connecting the power element and the microcomputer to each other;
The motor device according to claim 1, further comprising a second connection line that connects the magnetic detection element and the microcomputer to each other.
A cylindrical motor housing that houses the motor;
A cover that is attached to one end of the motor housing in the axial direction of the rotating shaft and that houses the power board and the control board;
A bearing that is provided in the motor housing and rotatably supports the rotating shaft with respect to an inner surface of the motor housing,
The motor device according to claim 1 or 2, wherein the one end of the rotation shaft does not protrude beyond the one end of the motor housing.
The motor device according to any one of claims 1 to 3, wherein the microcomputer is provided in a portion of the control board that intersects an axis of the rotation shaft.