Actuator device

Abstract

According to one aspect of the present invention, an actuator device is provided with: a drive unit that is movable in a first direction; a sensor magnet that is magnetized in the first direction, extends in the first direction, and is fixed to the drive unit; and a magnetic sensor that is disposed so as to face the sensor magnet in a second direction intersecting the first direction, and that detects the magnetic flux of the sensor magnet. Viewed from the second direction, the width of the sensor magnet at a portion where the center of gravity of the sensor magnet is located is wider than the width of both ends of the sensor magnet in the first direction.

Description

Technical Field

[0001] The present invention relates to an actuator device. Background Art

[0002] There is known a direct-acting actuator in which a magnet is fixed to a reciprocating support member and the position of the support member is controlled based on the magnetic flux of the magnet detected by an IC sensor (for example, Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-080131 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In the direct-acting actuator as described above, the magnetic flux density of the magnet in the magnetization direction decreases near the magnetic pole boundary that is the boundary of a pair of magnetic poles. Therefore, sometimes the magnetic flux density detected by the IC sensor when it is opposite to the magnetic pole boundary of the magnet is smaller than the lower limit of the magnetic flux density that the IC sensor can detect. In this case, there is a concern that the position of the magnet and the position of the support member cannot be detected with high accuracy by the IC sensor.

[0008] In view of the above circumstances, one object of one aspect of the present invention is to provide an actuator device capable of increasing the magnetic flux density at the magnetic pole boundary of a sensor magnet detected by a magnetic sensor.

[0009] Solutions to Solve Problems

[0010] An embodiment of the actuator device of the present invention comprises: a driving unit that is movable in a first direction; a sensor magnet that has the first direction as a magnetization direction, extends in the first direction, and is fixed to the driving unit; and a magnetic sensor that is arranged to face the sensor magnet in a second direction intersecting the first direction and detects the magnetic flux of the sensor magnet. When viewed from the second direction, the width of the sensor magnet at a portion where the center of gravity of the sensor magnet is located is wider than the width of the sensor magnet at both ends in the first direction.

[0011] Effects of the Invention

[0012] According to one aspect of the present invention, in the actuator device, it is possible to increase the magnetic flux density at the magnetic pole boundary of the sensor magnet detected by the magnetic sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a cross-sectional view showing an actuator device according to one embodiment.

[0014] Figure 2 It is a perspective view showing a part of the actuator device according to one embodiment.

[0015] Figure 3 This is a diagram showing an example of the magnetic flux density of a magnetic body detected by the magnetic sensor according to one embodiment.

[0016] Figure 4 This is a perspective view showing a part of an actuator device according to a modified example of one embodiment.

[0017] In the figure:

[0018] 10, 110—actuator device, 20—motor part, 24—shaft, 24a—second threaded part, 40—driving part, 41a—first threaded part, 45, 145—sensor magnet, 70—circuit substrate, 71—magnetic sensor, D1—first direction, D2—second direction. DETAILED DESCRIPTION

[0019] In each figure, the first direction D1 is the direction in which the driving unit can move. In the following description, the side (+D1 side) to which the arrow of the first direction D1 points is referred to as the "lower side", and the side opposite to the side to which the arrow of the first direction D1 points (-D1 side) is referred to as the "upper side". In addition, the upper side and the lower side are merely names used to describe the relative positional relationship of each part, and the actual configuration relationship may be a configuration relationship other than the configuration relationship indicated by these names.

[0020] In each figure, the second direction D2 is a direction intersecting the first direction D1. In the present embodiment, the second direction D2 is orthogonal to the first direction D1. In the following description, the side (+D2 side) to which the arrow of the second direction D2 points is referred to as "one side of the second direction D2", and the side opposite to the side to which the arrow of the second direction D2 points (-D2 side) is referred to as "the other side of the second direction D2".

[0021] In each figure, the third direction D3 is a direction orthogonal to both the first direction D1 and the second direction D2. In the present embodiment, the third direction D3 is the width direction of the sensor magnet. In the following description, the side (+D3 side) to which the arrow of the third direction D3 points is referred to as "one side in the width direction", and the side opposite to the side to which the arrow of the third direction D3 points (-D3 side) is referred to as "the other side in the width direction".

[0022] The rotation axis J shown in each figure is an imaginary axis extending in a direction parallel to the first direction D1. The rotation axis J is the central axis of the motor shaft. In the following description, the radial direction centered on the rotation axis J is referred to as the "radial direction". The circumferential direction centered on the rotation axis J is referred to as the "circumferential direction". In each figure, the circumferential direction is indicated by an arrow θ.

[0023] <Implementation Method>

[0024] Figure 1 The actuator device 10 of the present embodiment shown is a linear actuator that moves a driven object (not shown) in a first direction D1. The actuator device 10 extends along the first direction D1 as a whole. The actuator device 10 includes a housing 11, a motor unit 20, a drive unit 40, a sensor magnet 45, an output unit 50, a circuit board 70, and a magnetic sensor 71.

[0025] The housing 11 accommodates the motor unit 20, the drive unit 40, the sensor magnet 45, the circuit board 70, and the magnetic sensor 71. The housing 11 includes a housing body 12, a cover member 13, a first bearing holding member 14, and a drive unit accommodating member 15. The cover member 13 is fixed to the upper end of the housing body 12. The first bearing holding member 14 is accommodated inside the housing body 12. The drive unit accommodating member 15 is fixed to the lower end of the housing body 12.

[0026] The housing body 12 is substantially cylindrical and extends in the first direction D1 around the rotation axis J. The housing body 12 is open at the top. The housing body 12 accommodates the motor 20 therein. The housing body 12 has a peripheral wall 12a and a bottom wall 12d.

[0027] The peripheral wall 12a is substantially cylindrical and extends in the first direction D1 around the rotation axis J. The peripheral wall 12a surrounds the motor 20 from the radially outer side. The upper end of the peripheral wall 12a is the upper end of the housing body 12. The peripheral wall 12a has an opening 12b opened at the upper side.

[0028] The bottom wall portion 12d is a plate-shaped portion extending in a direction perpendicular to the first direction D1. The radial outer edge of the bottom wall portion 12d is connected to the lower end of the peripheral wall portion 12a. The bottom wall portion 12d separates the interior of the housing body 12 from the interior of the drive unit storage component 15. The second bearing holding portion 12e, the through hole 12f, and the insertion hole 12g are provided on the bottom wall portion 12d.

[0029] The second bearing holding portion 12e protrudes upward from the bottom wall portion 12d. The second bearing holding portion 12e is substantially cylindrical centered on the rotation axis J. The second bearing holding portion 12e is open at the upper side. The second bearing 62 is held on the inner peripheral surface of the second bearing holding portion 12e.

[0030] The through hole 12f and the insertion hole 12g are holes that penetrate the bottom wall portion 12d in the first direction D1. When viewed from the first direction D1, the through hole 12f is a substantially circular shape centered on the rotation axis J. The inner diameter of the through hole 12f is smaller than the inner diameter of the second bearing retaining portion 12e. The insertion hole 12g is provided at an edge portion of one side (+D2 side) of the bottom wall portion 12d in the second direction D2.

[0031] The cover member 13 is in the shape of a disk centered on the rotation axis J. The plate surface of the cover member 13 faces the first direction D1. The cover member 13 is fixed to the upper end of the peripheral wall portion 12a. The cover member 13 closes the opening portion 12b from the upper side.

[0032] The first bearing holding portion 14 is substantially annular centered on the rotation axis J. The outer peripheral surface of the first bearing holding portion 14 is fixed to the inner peripheral surface of the peripheral wall portion 12a. Thus, the first bearing holding portion 14 is fixed to the housing body 12. The first bearing 61 is held on the inner peripheral surface of the first bearing holding portion 14.

[0033] The drive unit storage component 15 is substantially cylindrical and extends along the first direction D1 with the rotation axis J as the center. The drive unit storage component 15 is open at the upper side. The drive unit storage component 15 stores the drive unit 40, the sensor magnet 45, the output unit 50, the circuit substrate 70, and the magnetic sensor 71 therein. The drive unit storage component 15 has an annular wall portion 15a and a bottom portion 15d.

[0034] The annular wall portion 15a is roughly cylindrical and extends along the first direction D1 with the rotation axis J as the center. The annular wall portion 15a surrounds the drive portion 40, the sensor magnet 45, the output portion 50, the circuit substrate 70 and the magnetic sensor 71 from the radial outside. The annular wall portion 15a is open on the upper side. A plurality of substrate holding portions 15b are provided on the annular wall portion 15a. Each substrate holding portion 15b is a columnar portion protruding from a portion on one side (+D2 side) of the annular wall portion 15a in the second direction D2 to the other side (-D2 side) of the second direction D2. Each substrate holding portion 15b holds the circuit substrate 70.

[0035] The bottom portion 15d is in the shape of a plate extending in a direction perpendicular to the first direction D1. The radial outer edge of the bottom portion 15d is connected to the lower end of the annular wall portion 15a. The bottom portion 15d is provided with a sealing member holding portion 15e and a bottom through hole 15f.

[0036] The seal member holding portion 15e protrudes downward from the bottom portion 15d. The seal member holding portion 15e is substantially annular shaped with the rotation axis J as the center. The seal member holding portion 15e is open at the bottom. The seal member 63 is held on the inner side surface of the seal member holding portion 15e.

[0037] The bottom through hole 15f is a hole that penetrates the bottom 15d in the first direction D1. When viewed from the first direction D1, the bottom through hole 15f is a substantially circular shape centered on the rotation axis J. The inner diameter of the bottom through hole 15f is smaller than the inner diameter of the sealing member holding portion 15e.

[0038] The motor unit 20 is accommodated in the housing body 12 and includes a rotor 21 and a stator 30 . In this embodiment, the motor unit 20 drives the rotor 21 to rotate about the rotation axis J by current supplied from the circuit board 70 , and transmits the power of the rotor 21 to the drive unit 40 .

[0039] The rotor 21 is rotatable about the rotation axis J. The rotor 21 includes a rotor core 22, a plurality of rotor magnets 23, and a shaft 24. That is, the motor unit 20 includes the shaft 24. The rotor core 22 is annular centered about the rotation axis J. The plurality of rotor magnets 23 are respectively fixed to the rotor core 22. The rotor magnets 23 are arranged at intervals from each other in the circumferential direction.

[0040] The shaft 24 is roughly cylindrical and extends along the first direction D1 with the rotation axis J as the center. The shaft 24 extends along the first direction D1 across the interior of the housing body 12 and the interior of the drive unit storage component 15. The shaft 24 passes through the interior of the rotor core 22 along the first direction D1. The rotor core 22 is fixed to the outer peripheral surface of the shaft 24. The portion of the shaft 24 that is higher than the rotor core 22 is supported by the first bearing 61 so as to be rotatable around the rotation axis J. The portion of the shaft 24 that is lower than the rotor core 22 is supported by the second bearing 62 so as to be rotatable around the rotation axis J. Thus, the shaft 24 can rotate around the rotation axis J as the center. The lower end of the shaft 24 passes through the through hole 12f along the first direction D1 and protrudes into the interior of the drive unit storage component 15. A second threaded portion 24a is provided on the shaft 24. The second threaded portion 24a is an external thread provided on the outer peripheral surface of the shaft 24 at a portion located inside the drive unit storage component 15.

[0041] The first bearing 61 and the second bearing 62 are annular in shape with the rotation axis J as the center. As described above, the first bearing 61 is held on the inner circumferential surface of the first bearing holding portion 14. The second bearing 62 is held on the inner circumferential surface of the second bearing holding portion 12e. As described above, the first bearing 61 and the second bearing 62 can support the shaft 24 rotatably around the rotation axis J. In the present embodiment, the first bearing 61 and the second bearing 62 are ball bearings. The first bearing 61 and the second bearing 62 may also be sliding bearings.

[0042] The stator 30 is arranged radially outside the rotor 21. The stator 30 is arranged to face the rotor 21 with a gap therebetween in the radial direction. The stator 30 includes a stator core 31, an insulator 32, and a coil portion 33.

[0043] The stator core 31 is annular and surrounds the rotor core 22 from the radially outer side. The stator core 31 is opposed to the rotor 21 with a gap in the radial direction. The stator core 31 is fixed to the inner peripheral surface of the peripheral wall portion 12a. Thus, the stator 30 is fixed to the housing 11. The insulator 32 is mounted on the stator core 31. The insulator 32 insulates the stator core 31 and the coil portion 33.

[0044] The coil portion 33 has a plurality of coil main bodies 33a and coil lead wires 33b. Each coil main body 33a is mounted on the stator core 31 via an insulator 32. Each coil main body 33a is arranged at intervals along the circumferential direction. The coil lead wires 33b are led out from the coil main body 33a to the lower side and connected to the circuit substrate 70. Thus, the coil portion 33 is electrically connected to the circuit substrate 70. When current is supplied from the circuit substrate 70 to the coil portion 33, the rotor 21 rotates around the rotation axis J. The circuit substrate 70 can control the rotation speed and rotation direction of the rotor 21 by controlling the current supplied to the coil portion 33. The circuit substrate 70 can control the moving speed and moving direction in the first direction D1 of the drive unit 40 by controlling the rotation speed and rotation direction of the rotor 21.

[0045] The driving unit 40 is housed inside the driving unit housing component 15. The driving unit 40 is connected to a portion of the shaft 24 located inside the driving unit housing component 15. The driving unit 40 converts the rotational motion of the motor unit 20 into a linear motion and transmits it to the output unit 50. The driving unit 40 is cylindrical and extends in the first direction D1. The driving unit 40 surrounds the rotation axis J. The driving unit 40 has a cylindrical portion 41 and a protruding portion 42.

[0046] The cylindrical portion 41 is substantially cylindrical and extends along the first direction D1 with the rotation axis J as the center. The cylindrical portion 41 is open on both sides of the first direction D1. The portion of the shaft 24 located inside the drive unit housing component 15 is inserted into the inside of the cylindrical portion 41. The lower end of the cylindrical portion 41 protrudes to the outside of the actuator device 10 through the bottom through hole 15f. The cylindrical portion 41 is provided with a first threaded portion 41a that meshes with the second threaded portion 24a. The first threaded portion 41a is an internal thread provided on the inner circumferential surface of the cylindrical portion 41.

[0047] The protrusion 42 protrudes from the cylindrical portion 41 to one side (+D2 side) in the second direction D2. The protrusion 42 faces the circuit board 70 with a gap in the second direction D2. The sensor magnet 45 is fixed to the end of the protrusion 42 on one side in the second direction D2.

[0048] The output portion 50 is fixed to the lower end of the cylindrical portion 41. The output portion 50 is located outside the housing 11. The output portion 50 has an output main body portion 51 and an output protrusion 52. The output main body portion 51 is in the shape of a plate protruding in the first direction D1. In the present embodiment, the output main body portion 51 is in the shape of a roughly quadrilateral plate extending in a direction orthogonal to the third direction D3. A mounting hole 53 is provided in the output main body portion 51. The mounting hole 53 is a hole that passes through the output main body portion 51 in the third direction D3. The output protrusion 52 protrudes upward from the upper end of the output main body portion 51. The output protrusion 52 is in the shape of a roughly circular plate centered on the rotation axis J. The output protrusion 52 is located inside the cylindrical portion 41. The output protrusion 52 is fixed to the inner circumferential surface of the cylindrical portion 41. Thus, the output portion 50 is fixed to the drive portion 40.

[0049] A driven object (not shown) that is moved in the first direction D1 by the actuator device 10 is mounted in the mounting hole 53. By mounting the driven object in the mounting hole 53, the output unit 50 can be prevented from rotating about the rotation axis J. Thus, the driving unit 40 fixed to the output unit 50 can also be prevented from rotating about the rotation axis J.

[0050] When current is supplied from the circuit substrate 70 to the stator 30 and the shaft 24 rotates around the rotation axis J, the second threaded portion 24a of the shaft 24 rotates relative to the first threaded portion 41a of the drive portion 40 around the rotation axis J. As described above, the rotation of the drive portion 40 around the rotation axis J is suppressed. Therefore, when the shaft 24 rotates around the rotation axis J, the first threaded portion 41a is conveyed in the first direction D1 relative to the second threaded portion 24a. Thus, the drive portion 40 can move in the first direction D1. When the drive portion 40 moves in the first direction D1, the output portion 50 fixed to the drive portion 40 moves in the first direction D1. Thus, the actuator device 10 can move a driven object (not shown) in the first direction D1.

[0051] According to the present embodiment, the driving part 40 is provided with a first threaded portion 41a on the inner circumferential surface and is in a cylindrical shape extending in the first direction D1, and a second threaded portion 24a meshing with the first threaded portion 41a is provided on the outer circumferential surface of the shaft 24. Thus, the rotational motion of the shaft 24 around the rotation axis J can be converted into a linear motion in the first direction D1 of the driving part 40 only by the first threaded portion 41a provided on the driving part 40 and the second threaded portion 24a provided on the shaft 24. Therefore, an additional component for converting the rotational motion of the shaft 24 into the linear motion of the driving part 40 is not required, so that the number of components and the increase in the manufacturing cost of the actuator device 10 can be suppressed.

[0052] The sealing member 63 is held on the inner peripheral surface of the sealing member holding portion 15e. In the present embodiment, the sealing member 63 is a lip seal having a lip portion on the radially inner side. The lip portion of the sealing member 63 contacts the outer peripheral surface of the cylindrical portion 41 of the driving portion 40. Thus, the sealing member 63 seals between the driving portion 40 and the housing 11.

[0053] The circuit substrate 70 is in the shape of a plate extending in a direction orthogonal to the second direction D2. The plate surface of the circuit substrate 70 faces the second direction D2. The circuit substrate 70 is arranged on one side (+D2 side) of the second direction D2 of the sensor magnet 45. The circuit substrate 70 is spaced apart from the sensor magnet 45 in the second direction D2. Although not shown in the figure, the circuit substrate 70 is provided with a plurality of substrate holes that penetrate the circuit substrate 70 in the second direction D2. Different substrate retaining portions 15b are inserted into each substrate hole. The substrate retaining portion 15b is fixed to the inner circumferential surface of each substrate hole. Thus, the circuit substrate 70 is fixed to the housing 11. A magnetic sensor 71 is mounted on the surface of the circuit substrate 70 facing the other side (-D2 side) of the second direction D2.

[0054] The magnetic sensor 71 is a sensor capable of detecting the magnetic flux of the sensor magnet 45 fixed to the protrusion 42 of the drive unit 40. The magnetic sensor 71 is arranged at a distance from the sensor magnet 45 in the second direction D2. In the second direction D2, the magnetic sensor 71 is arranged opposite to the sensor magnet 45. In the present embodiment, the magnetic sensor 71 is a magnetic sensor having a Hall element such as a Hall IC. The magnetic sensor 71 may also be a magnetic sensor having an MR (Magnetic Resistance) sensor element. The circuit substrate 70 can detect the position of the sensor magnet 45 in the first direction D1 by the magnetic flux of the sensor magnet 45 detected by the magnetic sensor 71. Thus, the circuit substrate 70 can detect the position of the drive unit 40 and the output unit 50 in the first direction D1. The circuit substrate 70 controls the motor unit 20 based on the magnetic flux of the sensor magnet 45 detected by the magnetic sensor 71. In more detail, the circuit substrate 70 controls the current supplied to the stator 30 based on the magnetic flux of the sensor magnet 45 detected by the magnetic sensor 71. Thus, the circuit board 70 controls the rotation speed, rotation direction, etc. of the rotor 21 , and determines the position of the driving unit 40 in the first direction D1 .

[0055] According to the present embodiment, the actuator device 10 includes a circuit substrate 70 on which a magnetic sensor 71 is mounted, and the circuit substrate 70 controls the motor unit 20 based on the magnetic flux of the sensor magnet 45 detected by the magnetic sensor 71. Thus, since the magnetic sensor 71 is mounted on the circuit substrate 70, it is not necessary to separately provide a signal line for electrically connecting the magnetic sensor 71 and the circuit substrate 70. Therefore, it is possible to suppress an increase in the number of components of the actuator device 10. In addition, it is not necessary to separately connect the signal line between the magnetic sensor 71 and the circuit substrate 70, so it is possible to suppress an increase in the number of manufacturing man-hours of the actuator device 10.

[0056] As described above, the sensor magnet 45 is fixed to the end portion of the protrusion 42 on one side (+D2 side) in the second direction D2. More specifically, the sensor magnet 45 is fixed to the surface of the outer surface of the protrusion 42 on one side facing the second direction D2. The sensor magnet 45 can move along the first direction D1 together with the drive unit 40. The sensor magnet 45 is spaced apart from the magnetic sensor 71 in the second direction D2.

[0057] like Figure 2 As shown, the sensor magnet 45 extends along the first direction D1. The sensor magnet 45 has the first direction D1 as its magnetization direction. In the present embodiment, the S-pole portion 45S of the sensor magnet 45 is the lower portion of the sensor magnet 45. The N-pole portion 45N of the sensor magnet 45 is the upper portion of the sensor magnet 45. Alternatively, the S-pole portion 45S is the upper portion of the sensor magnet 45, and the N-pole portion 45N is the lower portion of the sensor magnet 45. When viewed from the second direction D2, the width of the sensor magnet 45 increases as it moves from the ends on both sides of the first direction D1 toward the center of the first direction D1. In the present embodiment, the sensor magnet 45 is a plane-symmetrical shape with a plane passing through the center of the sensor magnet 45 in the first direction D1 and extending in a direction orthogonal to the first direction D1 as a symmetric plane. The sensor magnet 45 may also be a non-plane-symmetrical shape with respect to a plane passing through the center of the sensor magnet 45 in the first direction D1 and extending in a direction orthogonal to the first direction D1. The center of gravity 45c of the sensor magnet 45 is located at the center in the first direction D1 of the sensor magnet 45. In the first direction D1, the center of gravity 45c of the sensor magnet 45 may be located outside the center in the first direction D1 of the sensor magnet 45. When viewed from the second direction D2, the width of the sensor magnet 45 at the portion where the center of gravity 45c of the sensor magnet 45 is located is wider than the widths at both ends in the first direction D1 of the sensor magnet 45. The magnetic pole boundary 45e, which is the boundary between the S-pole portion 45S and the N-pole portion 45N, passes through the center of gravity 45c.

[0058] In the present embodiment, when viewed from the second direction D2, the ends of the sensor magnet 45 on both sides in the width direction (third direction D3) are curved. More specifically, the ends of the sensor magnet 45 on both sides in the width direction are curved protruding from the center of the first direction D1 to the outside in the width direction. In addition, the surface 45a of the sensor magnet 45 on one side (+D2 side) facing the second direction D2 and the surface 45b on the other side (-D2 side) facing the second direction D2 are flat. That is, the surfaces 45a and 45b of the sensor magnet 45 facing the second direction D2 are flat surfaces parallel to each other. Therefore, according to the present embodiment, compared with the case where the surfaces 45a and 45b of the sensor magnet 45 facing the second direction D2 are curved surfaces protruding along the second direction D2, the sensor magnet 45 can be suppressed from being enlarged in the second direction D2. Therefore, the actuator device 10 can be suppressed from being enlarged in the second direction D2.

[0059] Figure 3 1 is a diagram showing the relationship between the position of the sensor magnet 45 in the first direction D1 and the magnetic flux density of the sensor magnet 45 detected by the magnetic sensor 71 . Figure 3 The horizontal axis is the distance between the magnetic sensor 71 and the magnetic pole boundary 45e of the sensor magnet 45 in the first direction D1, that is, the magnetic distance Dm. When the magnetic distance Dm is 0, the magnetic sensor 71 is opposite to the magnetic pole boundary 45e of the sensor magnet 45 in the second direction D2. When the magnetic distance Dm is positive, the magnetic pole boundary 45e is located below the magnetic sensor 71. When the magnetic distance Dm is negative, the magnetic pole boundary 45e is located above the magnetic sensor 71. Figure 3 The vertical axis is the magnetic flux density of the sensor magnet 45 detected by the magnetic sensor 71, that is, the detected magnetic flux density Bd. Figure 3 The detectable magnetic flux density Bu shown is the lower limit of the magnetic flux density that can be detected by the magnetic sensor 71. When the detected magnetic flux density Bd is less than the detectable magnetic flux density Bu, the detection accuracy of the magnetic flux density of the magnetic sensor 71 decreases. As a result, the detection accuracy of the position of the driving unit 40 in the first direction D1 detected by the circuit substrate 70 decreases, and the accuracy of the circuit substrate 70 in determining the position of the driving unit 40 in the first direction D1 deteriorates.

[0060] First, the detection magnetic flux density Bd of the sensor magnet according to the comparative example of the present embodiment will be described. Figure 3In the figure, the detection magnetic flux density Bd of the sensor magnet of the comparative example is represented by a dotted line. Although not shown in the figure, the sensor magnet of the comparative example is a rectangular parallelepiped extending along the first direction D1. When viewed from the second direction D2, the sensor magnet of the comparative example is a rectangle. The volume of the sensor magnet of the comparative example is the same as the volume of the sensor magnet 45 of the present embodiment. Other structures of the sensor magnet of the comparative example are the same as the structures of the sensor magnet 45 of the present embodiment. Figure 3 As shown, in the sensor magnet of the comparative example, the detected magnetic flux density Bd decreases as it moves from the two ends of the first direction D1 toward the center of the first direction D1. When the magnet distance Dm is 0 and near 0, that is, when the magnetic sensor 71 is opposite to the magnetic pole boundary of the sensor magnet and the vicinity of the magnetic pole boundary in the second direction D2, the detected magnetic flux density Bd is less than the detectable magnetic flux density Bu. Therefore, in the case of the rectangular sensor magnet of the comparative example, in order to make the detected magnetic flux density Bd at the magnetic pole boundary of the sensor magnet and the vicinity of the magnetic pole boundary greater than the detectable magnetic flux density Bu, it is necessary to enlarge the sensor magnet itself. As a result, the manufacturing cost of the sensor magnet increases, and the actuator device 10 is enlarged. In addition, in the following description, the magnetic pole boundary and the vicinity of the magnetic pole boundary in the sensor magnet are sometimes referred to as "the vicinity of the magnetic pole boundary".

[0061] Next, the detection magnetic flux density Bd of the sensor magnet 45 of this embodiment will be described. Figure 3 , the detection magnetic flux density Bd of the sensor magnet 45 is indicated by a solid line. As in the sensor magnet of the comparative example, in the sensor magnet 45, the detection magnetic flux density Bd decreases as it moves from both ends of the first direction D1 toward the center of the first direction D1. However, in the sensor magnet 45 of the present embodiment, the detection magnetic flux density Bd detected by the magnetic sensor 71 when it is opposed to the vicinity of the magnetic pole boundary 45e in the second direction D2 is greater than the detectable magnetic flux density Bu.

[0062] According to the present embodiment, the actuator device 10 includes: a sensor magnet 45, which has a first direction D1 as a magnetization direction, extends along the first direction D1, and is fixed to the drive unit 40; and a magnetic sensor 71, which is arranged opposite to the sensor magnet 45 in the second direction D2 and detects the magnetic flux of the sensor magnet 45, and the width of the sensor magnet 45 at the portion where the center of gravity 45c of the sensor magnet 45 is located as viewed from the second direction D2 is wider than the width of the sensor magnet 45 at both ends in the first direction D1. Therefore, compared with the sensor magnet of the comparative example whose shape as viewed from the second direction D2 is a rectangle, the sensor magnet 45 of the present embodiment can easily increase the volume near the magnetic pole boundary 45e. Therefore, in the sensor magnet 45 of the present embodiment, the magnetic flux density near the magnetic pole boundary 45e can be increased. Therefore, as Figure 3As shown, in this embodiment, it is possible to improve the detection magnetic flux density Bd near the magnetic pole boundary 45e while suppressing the enlargement of the sensor magnet 45. Therefore, the detection magnetic flux density Bd near the magnetic pole boundary 45e can be made greater than the detectable magnetic flux density Bu. As a result, the magnetic sensor 71 can detect the magnetic flux density near the magnetic pole boundary 45e with high accuracy, so that the accuracy of the circuit substrate 70 in detecting the position of the drive unit 40 in the first direction D1 can be improved. Therefore, the position of the drive unit 40 in the first direction D1 can be determined with high accuracy by the circuit substrate 70. In addition, since it is possible to suppress the enlargement of the sensor magnet 45, it is possible to suppress the increase in the manufacturing cost of the sensor magnet 45, and it is possible to suppress the enlargement of the actuator device 10.

[0063] According to the present embodiment, when viewed from the second direction D2, the ends of both sides of the sensor magnet 45 in the width direction (third direction D3) are curved. Figure 3 As shown, it is easy to make the detected magnetic flux density Bd relative to the magnet distance Dm into a smooth curve. As a result, compared with the case where the detected magnetic flux density Bd relative to the magnet distance Dm changes sharply, the circuit substrate 70 can detect the position of the driving unit 40 in the first direction D1 with high accuracy based on the detection result of the magnetic sensor 71. Therefore, the position of the driving unit 40 in the first direction D1 can be determined with higher accuracy by the circuit substrate 70.

[0064] <Modification>

[0065] Figure 4 1 is a perspective view showing a part of the actuator device 110 according to the present modification. In the following description, the same reference numerals are used for the same components as those in the above-mentioned embodiment, and the description thereof may be omitted.

[0066] like Figure 4As shown, when viewed from the second direction D2, the end of one side (+D3 side) of the width direction of the sensor magnet 145 of this modification is curved, and the end of the other side (-D3 side) of the width direction of the sensor magnet 145 is straight. The sensor magnet 145 has the first direction D1 as the magnetization direction. In this modification, the S-pole portion 145S of the sensor magnet 145 is the lower part of the sensor magnet 145. The N-pole portion 145N of the sensor magnet 145 is the upper part of the sensor magnet 145. When viewed from the second direction D2, the width of the sensor magnet 145 widens from the ends on both sides of the first direction D1 toward the center of the first direction D1. In this embodiment, the center of gravity 145c of the sensor magnet 145 is located at the center of the first direction D1 of the sensor magnet 145. In the first direction D1, the center of gravity 145c of the sensor magnet 145 may also be located outside the center of the first direction D1 of the sensor magnet 145. A magnetic pole boundary 145e which is a boundary between the S-pole portion 145S and the N-pole portion 145N passes through the center of gravity 145c.

[0067] Although not shown in the figure, the detection magnetic flux density Bd of the sensor magnet 145 of this modification is the same as the detection magnetic flux density Bd of the sensor magnet 45 of the above-mentioned embodiment. That is, the detection magnetic flux density Bd when the magnet distance Dm is near 0, that is, when the magnetic sensor 71 is opposite to the vicinity of the magnetic pole boundary 145e in the second direction D2, is greater than the detectable magnetic flux density Bu. Therefore, according to this modification, the magnetic sensor 71 can detect the magnetic flux density near the magnetic pole boundary 145e with high accuracy, so that the accuracy of the circuit substrate 70 in detecting the position of the drive unit 40 in the first direction D1 can be improved. Therefore, the position of the drive unit 40 in the first direction D1 can be determined with high accuracy by the circuit substrate 70. In addition, as in the above-mentioned embodiment, the sensor magnet 145 can be suppressed from being enlarged, so the manufacturing cost of the sensor magnet 145 can be suppressed from increasing, and the actuator device 110 can be suppressed from being enlarged.

[0068] According to this modification, when viewed from the second direction D2, the end of one side (+D3 side) of the width direction of the sensor magnet 145 is curved, and the end of the other side (-D3 side) of the width direction of the sensor magnet 145 is straight. Therefore, as in the above-mentioned embodiment, it is easy to make the detection magnetic flux density Bd relative to the magnet distance Dm a smooth curve. As a result, compared with the case where the detection magnetic flux density Bd relative to the magnet distance Dm changes sharply, the circuit substrate 70 can detect the position of the drive unit 40 in the first direction D1 with high accuracy based on the detection result of the magnetic sensor 71. Therefore, the position of the drive unit 40 in the first direction D1 can be determined with higher accuracy by the circuit substrate 70.

[0069] The present invention is not limited to the above-mentioned embodiments, and other structures and other methods can also be adopted within the scope of the technical concept of the present invention. For example, when viewed from the second direction, the width of the sensor magnet can also be a shape that widens linearly from both ends of the first direction toward the center of the first direction.

[0070] The magnetic sensor may be mounted on a substrate different from the circuit substrate. In this case, the circuit substrate and the substrate are electrically connected via a signal line or the like.

[0071] The application of the actuator device to which the present invention is applied is not particularly limited. The actuator device can be mounted on any equipment. The actuator device can be mounted on a vehicle, for example. In addition, the various structures described above in this specification can be appropriately combined within the scope of no contradiction.

[0072] Furthermore, the present technology can adopt the following structures.

[0073] (1) An actuator device comprising: a driving unit that can move along a first direction; a sensor magnet that has the first direction as its magnetization direction, extends along the first direction, and is fixed to the driving unit; and a magnetic sensor that is arranged opposite to the sensor magnet in a second direction intersecting the first direction and detects the magnetic flux of the sensor magnet, wherein the width of the sensor magnet at a portion where the center of gravity of the sensor magnet is located, as viewed from the second direction, is wider than the width of the sensor magnet at both ends in the first direction.

[0074] (2) The actuator device according to (1), wherein a surface of the sensor magnet facing the second direction is flat.

[0075] (3) The actuator device according to (1) or (2), wherein end portions on both sides in the width direction of the sensor magnet are curved when viewed from the second direction.

[0076] (4) An actuator device according to (1) or (2), wherein when viewed from the second direction, an end portion of one side in the width direction of the sensor magnet is curved, and an end portion of the other side in the width direction of the sensor magnet is straight.

[0077] (5) An actuator device according to any one of (1) to (4), wherein the motor portion has a shaft extending in the first direction and rotatable around a rotation axis extending in a direction parallel to the first direction, the drive portion having a first threaded portion on an inner circumferential surface and being in a cylindrical shape extending in the first direction, and a second threaded portion meshing with the first threaded portion being provided on an outer circumferential surface of the shaft.

[0078] (6) The actuator device according to (5), further comprising a circuit board on which the magnetic sensor is mounted, wherein the circuit board controls the motor unit based on the magnetic flux of the sensor magnet detected by the magnetic sensor.

Claims

1. An actuator device, characterized in that: have: a driving portion capable of moving along a first direction; a sensor magnet, which has the first direction as its magnetization direction, extends along the first direction, and is fixed to the driving part; as well as a magnetic sensor disposed opposite to the sensor magnet in a second direction intersecting the first direction and detecting a magnetic flux of the sensor magnet, When viewed from the second direction, the width of the sensor magnet at a portion where the center of gravity of the sensor magnet is located is wider than the widths of both ends of the sensor magnet in the first direction.

2. The actuator device according to claim 1, characterized in that A surface of the sensor magnet facing the second direction is planar.

3. The actuator device according to claim 1 or 2, characterized in that: When viewed from the second direction, ends of both sides of the sensor magnet in the width direction are curved.

4. The actuator device according to claim 1 or 2, characterized in that: When viewed from the second direction, an end portion of the sensor magnet on one side in the width direction is curved, and an end portion of the sensor magnet on the other side in the width direction is linear.

5. The actuator device according to claim 1 or 2, characterized in that: A motor unit is provided, the motor unit having a shaft extending in the first direction and rotatable around a rotation axis extending in a direction parallel to the first direction, The driving portion has a first threaded portion on an inner peripheral surface thereof and is in a cylindrical shape extending in the first direction. A second threaded portion meshing with the first threaded portion is provided on an outer peripheral surface of the shaft.

6. The actuator device according to claim 5, characterized in that A circuit board on which the magnetic sensor is mounted is provided, The circuit substrate controls the motor unit based on the magnetic flux of the sensor magnet detected by the magnetic sensor.

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