Electric actuator

Abstract

According to one mode of the utility model, the electric actuator is provided with a driven part which is driven in a reciprocating manner in a first direction; a magnet part fixed to the driven member; and a magnetic sensor that is disposed facing the magnet section in a second direction intersecting the first direction and that detects the magnetic flux of the magnet section, the magnet section having: a magnet main body that is composed of a permanent magnet and that has the first direction as the magnetization direction; and a magnetic member which is made of a magnetic material, is connected to the magnet body, extends in the first direction, and is longer than the magnet body in the first direction.

Description

Technical Field

[0001] This utility model relates to an electric actuator. Background Technology

[0002] A type of direct-acting actuator is known, in which a magnet is fixed on a reciprocating support component, and the position of the support component is controlled based on the magnetic flux of the magnet detected by an IC sensor.

[0003] [Existing Technical Documents]

[0004] [Patent Literature]

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-080131 Utility Model Content

[0006] In direct-acting actuators like those described above, an IC sensor is used to detect changes in magnetic flux density accompanying the movement of a magnet. When using such IC sensors, to improve detection sensitivity, the magnet is sometimes made larger, or an expensive magnet material is chosen. This results in a high cost for the direct-acting actuator.

[0007] In view of the above, one of the objectives of this invention is to provide an electric actuator that can ensure the position detection accuracy of the driven component and achieve low cost.

[0008] One embodiment of the electric actuator of this utility model includes: a driven component that is reciprocated in a first direction; a magnet portion fixed to the driven component; and a magnetic sensor disposed opposite to the magnet portion in a second direction intersecting the first direction, and detecting the magnetic flux of the magnet portion. The magnet portion has: a magnet body made of a permanent magnet with the first direction as the magnetization direction; and a magnetic component made of a magnetic material connected to the magnet body and extending along the first direction, being longer than the magnet body in the first direction.

[0009] According to one aspect of the present invention, an electric actuator is provided that can ensure the position detection accuracy of the driven component and achieve low cost. Attached Figure Description

[0010] Figure 1 This is a cross-sectional view showing one embodiment of an electric actuator.

[0011] Figure 2 This is a cross-sectional view showing the magnet section and magnet body of an electric actuator according to one embodiment.

[0012] Figure 3 This is a perspective view showing the structure of the magnet part according to one embodiment.

[0013] Figure 4 This is a perspective view of a magnetic component of a magnet section according to one embodiment.

[0014] Figure 5 This is a three-dimensional unfolded view showing the structure of the magnet part in a modified embodiment.

[0015] Figure 6 This is a perspective view showing the magnet portion in a modified embodiment. Detailed Implementation

[0016] In the accompanying drawings, the first direction D1 is the direction in which the drive unit can move. In the following description, the side towards which the arrow of the first direction D1 points (+D1 side) is referred to as "one side of the first direction D1," and the opposite side (-D1 side) of the side towards which the arrow of the first direction D1 points is referred to as "the other side of the first direction D1." In the accompanying drawings, the second direction D2 is a direction intersecting the first direction D1. In this embodiment, the second direction D2 is orthogonal to the first direction D1. In the following description, the side towards which the arrow of the second direction D2 points (+D2 side) is referred to as "one side of the second direction D2," and the opposite side (-D2 side) of the side towards which the arrow of the second direction D2 points is referred to as "the other side of the second direction D2." In the accompanying drawings, the third direction D3 is a direction orthogonal to both the first direction D1 and the second direction D2.

[0017] Figure 1 The rotation axis J shown is an imaginary axis extending in a direction parallel to the first direction D1. Rotation axis J is the central axis of the motor shaft. In the following description, the radial direction centered on rotation axis J will be simply referred to as "radial." The circumferential direction centered on rotation axis J will be simply referred to as "circumferential." Figure 1 In the diagram, the circumferential direction is indicated by the arrow θ.

[0018] <Implementation Method>

[0019] Figure 1 The electric actuator 10 shown in this embodiment is a linear actuator that moves a driven object (not shown) in the first direction D1. The electric actuator 10 extends generally along the first direction D1. The electric actuator 10 includes a housing 11, a motor 20, a driven component 40, a magnet 80, an output 50, a circuit board 70, and a magnetic sensor 71.

[0020] The housing 11 internally houses a motor unit 20, a driven component 40, a magnet unit 80, a circuit board 70, and a magnetic sensor 71. The housing 11 has a main body 12, a cover component 13, a first bearing retainer 14, and a drive unit housing component 15. The cover component 13 is fixed to the end of the main body 12 on the other side in the first direction D1. The first bearing retainer 14 is housed inside the main body 12. The drive unit housing component 15 is fixed to the end of the main body 12 on the first direction D1 side.

[0021] The main body 12 of the housing is generally cylindrical, extending along a first direction D1 with the rotation axis J as the center. The main body 12 of the housing has an opening on the other side of the first direction D1. The main body 12 of the housing houses the motor 20. The main body 12 of the housing has a peripheral wall 12a and a bottom wall 12d.

[0022] The peripheral wall portion 12a is generally cylindrical, extending along a first direction D1 with the rotation axis J as the center. The peripheral wall portion 12a surrounds the motor portion 20 radially outward. The end of the peripheral wall portion 12a on the other side of the first direction D1 is the end of the housing body portion 12 on the other side of the first direction D1. The peripheral wall portion 12a has an opening 12b that opens on the other side of the first direction D1.

[0023] The bottom wall portion 12d is a plate-shaped portion that extends in a direction orthogonal to the first direction D1. The radial outer edge of the bottom wall portion 12d is connected to the end of the peripheral wall portion 12a on the first direction D1 side. The bottom wall portion 12d separates the interior of the housing body portion 12 from the interior of the drive portion housing member 15. A second bearing retaining portion 12e, a through hole 12f, and an insertion hole 12g are provided on the bottom wall portion 12d.

[0024] The second bearing retaining portion 12e protrudes from the bottom wall portion 12d to the other side in the first direction D1. The second bearing retaining portion 12e is generally cylindrical about the axis of rotation J. The second bearing retaining portion 12e is open on the other side in the first direction D1. A second bearing 62, which is annular when viewed from the first direction D1, is held on the inner circumferential surface of the second bearing retaining portion 12e.

[0025] 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 approximately circular about the axis of rotation 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 on the edge of the bottom wall portion 12d on the second direction D2 side (+D2 side).

[0026] The cover component 13 is in the shape of a circular plate centered on the axis of rotation J. The plate surface of the cover component 13 faces the first direction D1. The cover component 13 is fixed to the end of the peripheral wall portion 12a on the other side of the first direction D1. The cover component 13 blocks the opening portion 12b from the other side of the first direction D1.

[0027] The first bearing retaining portion 14 is approximately annular about the axis of rotation J. The outer peripheral surface of the first bearing retaining portion 14 is fixed to the inner peripheral surface of the peripheral wall portion 12a. Thus, the first bearing retaining portion 14 is fixed to the housing body portion 12. A first bearing 61, which is annular when viewed from the first direction D1, is held on the inner peripheral surface of the first bearing retaining portion 14.

[0028] The drive unit housing 15 is generally cylindrical, extending along a first direction D1 with the rotation axis J as the center. The drive unit housing 15 internally houses the driven component 40, the magnet 80, the output component 50, the circuit board 70, and the magnetic sensor 71. The drive unit housing 15 has an annular wall 15a and a bottom 15d.

[0029] The annular wall portion 15a is generally cylindrical, extending along a first direction D1 with the rotation axis J as its center. The annular wall portion 15a radially surrounds the driven component 40, the magnet portion 80, the output portion 50, the circuit board 70, and the magnetic sensor 71. The annular wall portion 15a opens on the other side of the first direction D1. A plurality of board holding portions 15b are provided on the annular wall portion 15a. Each board holding portion 15b holds the circuit board 70.

[0030] The bottom 15d is plate-shaped and extends in a direction orthogonal to the first direction D1. The radial outer edge of the bottom 15d is connected to the end of the annular wall portion 15a on the first direction D1 side. A sealing member retaining portion 15e and a bottom through hole 15f are provided on the bottom 15d.

[0031] The sealing component retaining portion 15e protrudes from the bottom 15d toward the first direction D1 side. The sealing component retaining portion 15e is generally annular about the rotation axis J. The sealing component retaining portion 15e is open on the first direction D1 side. A sealing component 63, which is annular when viewed from the first direction D1, is held on the inner surface of the sealing component retaining portion 15e.

[0032] The bottom through-hole 15f is a hole that penetrates the bottom 15d in the first direction D1. Viewed from the first direction D1, the bottom through-hole 15f is approximately circular about the axis of rotation J. The inner diameter of the bottom through-hole 15f is smaller than the inner diameter of the sealing member retaining part 15e.

[0033] The motor unit 20 is housed inside the main body 12 of the housing. The motor unit 20 has a rotor 21 and a stator 30. In this embodiment, the motor unit 20 drives the rotor 21 to rotate around the rotation axis J by current supplied from the circuit board 70, and transmits the power of the rotor 21 to the driven component 40.

[0034] The rotor 21 is capable of rotating about the rotation axis J. The rotor 21 has a rotor core 22, a plurality of rotor magnets 23, and a shaft 24. That is, the motor unit 20 has a shaft 24. The rotor core 22 is in the shape of a ring 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 along the circumference.

[0035] Shaft 24 is generally cylindrical, extending along a first direction D1 with the rotation axis J as its center. Shaft 24 extends along the first direction D1, passing through the interior of the housing body 12 and the drive unit housing 15. Shaft 24 passes through the interior of the rotor core 22 in the first direction D1. The rotor core 22 is fixed to the outer circumferential surface of shaft 24. Shaft 24 is supported by a first bearing 61 and a second bearing 62, enabling it to rotate about the rotation axis J. The end of shaft 24 on the first direction D1 side passes through a through hole 12f in the first direction D1 and protrudes into the interior of the drive unit housing 15. Shaft 24 is provided with a second threaded portion 24a. The second threaded portion 24a is an external thread provided on the portion of the outer circumferential surface of shaft 24 located inside the drive unit housing 15.

[0036] The stator 30 is disposed radially outside the rotor 21. The stator 30 is disposed opposite the rotor 21 in the radial direction with a gap. The stator 30 has a stator core 31, an insulator 32, and a coil section 33.

[0037] The stator core 31 is annular, surrounding the rotor core 22 radially outward. The stator core 31 is radially opposed to the rotor 21 with a gap. The stator core 31 is fixed to the inner circumferential surface of the peripheral wall portion 12a. Thus, the stator 30 is fixed to the housing 11. An insulator 32 is mounted on the stator core 31. The insulator 32 insulates the stator core 31 from the coil portion 33.

[0038] The coil section 33 has multiple coil body sections 33a and coil lead wires 33b. Each coil body section 33a is mounted on the stator core 31 with an insulator 32 in between. The coil body sections 33a are arranged at intervals along the circumference. The coil lead wires 33b extend from the coil body sections 33a toward the first direction D1 and are connected to the circuit board 70. Thus, the coil section 33 is electrically connected to the circuit board 70. When current is supplied from the circuit board 70 to the coil section 33, the rotor 21 rotates about the rotation axis J. By controlling the current supplied to the coil section 33, the circuit board 70 can control the rotational speed and direction of the rotor 21. By controlling the rotational speed and direction of the rotor 21, the circuit board 70 can control the movement speed and direction of the driven component 40 in the first direction D1.

[0039] The driven component 40 is housed inside the drive unit housing component 15. The driven component 40 is connected to the portion of the shaft 24 located inside the drive unit housing component 15. The driven component 40 is reciprocated in the first direction D1 by the motor unit 20. The driven component 40 converts the rotational motion of the motor unit 20 into linear motion and transmits it to the output unit 50. The driven component 40 is cylindrical, extending along the first direction D1. Here, the driven component 40 is made of a non-magnetic material or a material weaker than the magnetic component 82 described later. The driven component 40 in this embodiment is, for example, made of non-magnetic resin. The driven component 40 surrounds the rotation axis J. The driven component 40 has a cylindrical portion 41 and a protrusion 42.

[0040] The cylindrical portion 41 is generally cylindrical, extending along a first direction D1 with the rotation axis J as its center. The cylindrical portion 41 has openings on both sides in the first direction D1. The portion of the shaft 24 located inside the drive housing 15 is inserted into the interior of the cylindrical portion 41. The end of the cylindrical portion 41 on the first direction D1 side protrudes to the outside of the electric actuator 10 via a bottom through-hole 15f. A first threaded portion 41a is provided on the cylindrical portion 41, engaging 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.

[0041] The protrusion 42 protrudes from the cylindrical portion 41 toward the second direction D2 side (+D2 side). The protrusion 42 and the circuit board 70 are spaced apart in the second direction D2. A magnet portion 80 is fixed to the end of the protrusion 42 on the second direction D2 side.

[0042] The output portion 50 is fixed to the end of the cylindrical portion 41 on one side of the first direction D1. 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 portion 52. The output main body portion 51 is plate-shaped and protrudes in the first direction D1. In this embodiment, the output main body portion 51 is a generally quadrilateral plate-shaped that extends in a direction orthogonal to the third direction D3. A mounting hole 53 is provided on 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 portion 52 protrudes from the end of the output main body portion 51 on the other side of the first direction D1. The output protrusion portion 52 is a generally circular plate-shaped with the rotation axis J as its center. The output protrusion portion 52 is located inside the cylindrical portion 41. The output protrusion portion 52 is fixed to the inner circumferential surface of the cylindrical portion 41. Thus, the output portion 50 is fixed to the driven member 40.

[0043] An unlabelled drive object, which moves in the first direction D1 via an electric actuator 10, is mounted in the mounting hole 53. By mounting the drive object in the mounting hole 53, rotation of the output section 50 about the rotation axis J is suppressed. Consequently, rotation of the driven component 40, which is fixed to the output section 50, about the rotation axis J is also suppressed.

[0044] When current is supplied from circuit board 70 to stator 30 and shaft 24 rotates about rotation axis J, the second threaded portion 24a of shaft 24 rotates relative to the first threaded portion 41a of driven member 40 about rotation axis J. As described above, rotation of driven member 40 about rotation axis J is suppressed. Therefore, when shaft 24 rotates about rotation axis J, first threaded portion 41a feeds relative to second threaded portion 24a in the first direction D1. As a result, driven member 40 can move in the first direction D1. When driven member 40 moves in the first direction D1, output portion 50 fixed to driven member 40 moves in the first direction D1. As a result, electric actuator 10 can move a driven object (not shown) in the first direction D1.

[0045] In this embodiment, the driven component 40 has a first threaded portion 41a on its inner circumferential surface and is cylindrical in shape extending along the first direction D1. A second threaded portion 24a, which engages with the first threaded portion 41a, is provided on the outer circumferential surface of the shaft 24. According to this structure, the rotational motion of the shaft 24 about the rotation axis J can be converted into linear motion of the driven component 40 in the first direction D1 using only the first threaded portion 41a of the driven component 40 and the second threaded portion 24a of the shaft 24. Therefore, no additional components are needed to convert the rotational motion of the shaft 24 into linear motion of the driven component 40, thus reducing the increase in the number of components and manufacturing cost of the electric actuator 10.

[0046] The sealing member 63 is held on the inner circumferential surface of the sealing member retaining portion 15e. In this embodiment, the sealing member 63 is a lip seal with a lip on its radially inner side. The lip of the sealing member 63 contacts the outer circumferential surface of the cylindrical portion 41 of the driven member 40. Thus, the sealing member 63 seals between the driven member 40 and the housing 11.

[0047] Figure 2 This is a cross-sectional view showing the magnet portion 80 and the magnetic sensor 71 of an electric actuator 10 according to one embodiment. Figure 3 This is a perspective view showing the structure of the magnet part 80 according to one embodiment. Figure 4 This is a perspective view showing the magnetic component 82 of the magnet section 80 according to one embodiment.

[0048] like Figure 1 , Figure 2 As shown, the magnet part 80 is fixed to the driven member 40. The magnet part 80 is movable together with the driven member 40 in a first direction D1. The magnet part 80 is spaced apart from the magnetic sensor 71 in a second direction D2. The magnet part 80 has a magnet body 81 and a magnetic component 82.

[0049] The magnet body 81 is fixed to the end of the protrusion 42 on one side (+D2 side) in the second direction D2. More specifically, a portion of the other side of the magnet body 81 in the second direction D2 is embedded in the protrusion 42. A portion of the magnet body 81 on one side in the second direction D2 protrudes radially outward relative to the protrusion 42. The magnet body 81 is, for example, cuboid in shape.

[0050] like Figure 2 , Figure 3 As shown, the magnet body 81 is a permanent magnet with a first direction D1 as its magnetization direction. That is, the magnet body 81 is composed of a permanent magnet. The magnet body 81 is, for example, a rare-earth magnet such as a neodymium magnet. In this embodiment, the S pole portion 81S of the magnet body 81 is a portion of the magnet body 81 on one side of the first direction D1. The N pole portion 81N of the magnet body 81 is a portion of the magnet body 81 on the other side of the first direction D1. The S pole portion 81S may also be a portion of the magnet body 81 on the other side of the first direction D1, and the N pole portion 81N may also be a portion of the magnet body 81 on one side of the first direction D1.

[0051] The magnetic component 82 extends along a first direction D1. The magnetic component 82 is cylindrical and extends along the first direction D1. The magnetic component 82 is longer than the magnet body 81 in the first direction D1. The magnetic component 82 protrudes from the magnet body 81 on both sides of the first direction D1. The magnet body 81 is disposed at the center of the magnetic component 82 in the first direction D1. The magnetic component 82 is made of a magnetic material such as iron. The magnetic component 82 is connected to the magnet body 81. Thus, the magnetic component 82 is magnetized by the magnetic field of the magnet body 81. In this embodiment, the portion of the magnetic component 82 on one side of the first direction D1 is called the S pole portion 82S. The portion on the other side of the first direction D1 is called the N pole portion 81N.

[0052] like Figure 2 , Figure 4 As shown, the magnetic component 82 has a first recess 83 on the side opposite to the magnet body 81 in the second direction D2. The first recess 83 is configured to be recessed in the second direction D2 away from the magnet body 81. The first recess 83 has a contact surface 83f and a pair of end faces 83s. The contact surface 83f faces the other side of the second direction D2. Figure 2 As shown, the contact surface 83f contacts the top surface 81t of the magnet body 81 facing the second direction D2. A pair of end faces 83s stand upright relative to the contact surface 83f from both sides of the first direction D1 to the other side of the second direction D2. The pair of end faces 83s extend along the surfaces intersecting the first direction D1. The pair of end faces 83s contacts the magnet side surfaces 81p of the magnet body 81 facing the first direction D1 and the other side, respectively. In this way, through the contact between the magnetic component 82 and the surface of the magnet body 81, the magnetic field of the magnet body 81 propagates efficiently to the magnetic component 82. As a result, the magnetic component 82 causes the magnetic flux from the magnet body 81 to extend to both sides of the first direction D1. The magnetic component 82 is connected to the magnet body 81, for example, by an adhesive.

[0053] like Figure 1 , Figure 2 As shown, the circuit board 70 is a plate-shaped structure extending in a direction orthogonal to the second direction D2. The plate surface of the circuit board 70 faces the second direction D2. The circuit board 70 is disposed on the second direction D2 side (+D2 side) of the magnet portion 80. The circuit board 70 is spaced apart from the magnet portion 80 in the second direction D2. Figure 1 As shown, although the icons are omitted, a plurality of substrate holes penetrating the circuit board 70 in the second direction D2 are provided on the circuit board 70. Different substrate holding portions 15b are inserted into each substrate hole. The substrate holding portion 15b is fixed to the inner peripheral surface of each substrate hole. Thus, the circuit board 70 is fixed to the housing 11. A magnetic sensor 71 is mounted on the surface of the circuit board 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 magnet portion 80 fixed to the protrusion 42 of the driven member 40. The magnetic sensor 71 and the magnet portion 80 are arranged at a distance from each other in the second direction D2. In the second direction D2, the magnetic sensor 71 and the magnet portion 80 are arranged opposite each other. In this embodiment, the magnetic sensor 71 is a magnetic sensor equipped with a Hall element such as a Hall IC. The magnetic sensor 71 may also be a magnetic sensor equipped with an MR (Magnetic Resistance) sensor element. The circuit board 70 can detect the position of the magnet portion 80 in the first direction D1 by detecting the magnetic flux of the magnet portion 80 detected by the magnetic sensor 71. Therefore, the circuit board 70 can detect the position of the driven member 40 and the output portion 50 in the first direction D1. The circuit board 70 controls the motor portion 20 based on the magnetic flux of the magnet portion 80 detected by the magnetic sensor 71. More specifically, the circuit board 70 controls the current supplied to the stator 30 based on the magnetic flux of the magnet portion 80 detected by the magnetic sensor 71. Thus, the circuit board 70 controls the rotational speed and direction of the rotor 21, and determines the position of the driven component 40 in the first direction D1.

[0055] The electric actuator 10 of this embodiment includes: a driven member 40, which is reciprocated in a first direction D1; a magnet part 80, which is fixed to the driven member 40; and a magnetic sensor 71, which is disposed opposite to the magnet part 80 in a second direction D2 intersecting the first direction D1, and detects the magnetic flux of the magnet part 80. The magnet part 80 includes: a magnet body 81, which is made of a permanent magnet and has the first direction D1 as the magnetization direction; and a magnetic member 82, which is made of a magnetic material, connected to the magnet body 81, extending along the first direction D1, and being longer than the magnet body 81 in the first direction D1.

[0056] According to this structure, the magnetic field of the magnet body 81 extends beyond the magnet body 81 in the first direction D1 via the magnetic component 82. Therefore, the magnetic sensor 71 can detect the position and displacement of the driven component 40 in the first direction D1 by detecting the magnetic flux from the magnet body 81 through the magnetic component 82 to the surrounding magnetic field. This allows for miniaturization of the magnet body 81 in the first direction D1 while ensuring the accuracy of position and displacement detection of the driven component 40. Thus, accurate position detection of the driven component 40 can be ensured, and cost reduction can be achieved.

[0057] In this embodiment, the magnetic component 82 has a first recess 83 on the side opposite to the magnet body 81 in the second direction D2. This first recess 83 is recessed away from the magnet body 81 in the second direction D2, and the magnet body 81 contacts the first recess 83. According to this structure, the magnetic flux of the magnet body 81 is efficiently transmitted to the magnetic component 82 through the contact between the magnet body 81 and the first recess 83. This increases the magnetic flux density transmitted from the magnet 80 to the magnetic sensor 71, thereby improving the detection accuracy of the magnetic sensor 71.

[0058] In this embodiment, the contact surface 83f between the magnetic component 82 and the magnet body 81 is planar. This structure ensures a large contact area between the magnetic component 82 and the magnet body 81, enabling efficient propagation of the magnetic field from the magnet body 81 to the magnetic component 82.

[0059] In this embodiment, the magnetic component 82 is positioned relative to the magnet body 81 on the side of the magnetic sensor 71 in the second direction D2. According to this structure, the magnetic field propagating from the magnet body 81 to the magnetic component 82 in the magnetic sensor 71 covers a wider range in the first direction D1, thus ensuring the accuracy of position and displacement detection of the driven component 40.

[0060] In this embodiment, the magnet body 81 is disposed at the center of the magnetic component 82 in the first direction D1. With this structure, the magnetic flux of the two magnets of the magnet body 81 can be balanced and effectively applied to one side and the other side of the magnetic component 82 in the first direction D1.

[0061] In this embodiment, the magnetic component 82 is cylindrical and extends along the first direction D1. According to this structure, when viewed from the first direction D1, the magnetic flux propagating from the magnet body 81 to the magnetic component 82 can act more evenly radially with respect to the magnetic component 82.

[0062] In this embodiment, the driven component 40 is made of a non-magnetic material or a material weaker than the magnetic component 82. According to this structure, the magnetic flux from the magnet body 81 and the magnetic component 82 can be efficiently detected by the magnetic sensor 71 while suppressing the effects of the magnetism of the driven component 40.

[0063] (Modified Example)

[0064] Figure 5 This is a perspective view showing the structure of the magnet part 80B in a modified embodiment. Figure 6 This is a perspective view showing the magnet part 80B in a modified embodiment.

[0065] In this modified example, the magnet part 80B differs from the magnet part 80 of the electric actuator 10 described above in that the magnet body 81B and the magnetic component 82B have different structures. Furthermore, components with the same form as those in the above embodiment are labeled with the same reference numerals, and their descriptions are omitted.

[0066] like Figure 5 , Figure 6 As shown, the magnet part 80B of this modified example has a magnet body 81B and a magnetic component 82B.

[0067] In this modified example, the magnetic component 82B is, for example, a prism extending along the first direction D1. The magnetic component 82B has a first recess 84 on the side opposite to the magnet body 81B in the second direction D2. The first recess 84 is configured to be recessed in the second direction D2 away from the magnet body 81B. The first recess 84 has a contact surface 84f and a pair of end faces 84s. The contact surface 84f faces the other side of the second direction D2. The pair of end faces 84s rise from both sides of the first direction D1 toward the other side of the second direction D2 relative to the contact surface 84f. The pair of end faces 84s extend along the surfaces intersecting the first direction D1.

[0068] The magnet body 81B has a second recess 85 on the side opposite to the magnetic component 82B in the second direction D2. The second recess 85 is recessed from the top surface 81t of the magnet body 81B toward the side away from the magnetic component 82B in the second direction D2. The second recess 85 has a bottom surface 85f facing the side in the second direction D2.

[0069] The magnetic component 82B contacts the second recess 85. Specifically, the first recess 84 of the magnetic component 82B engages with the second recess 85 of the magnet body 81B. The contact surface 84f of the first recess 84 contacts the bottom surface 85f of the second recess 85 of the magnet body 81B facing the second direction D2. A pair of end faces 84s respectively contact the magnet side surfaces 81p of the magnet body 81B facing the first direction D1 on one side and the other side.

[0070] Furthermore, in this modified example, in the magnetic component 82B, the top surface 82t facing the second direction D2 and the top surface 81t of the magnet body 81B are positioned at the same location in the second direction D2. That is, the top surface 82t and the top surface 81t are arranged along the same plane. As a result, the magnetic field propagating from the magnet body 81B to the magnetic component 82B is distributed more evenly around it.

[0071] In this modified example, the magnet body 81B has a second recess 85 on the side opposite to the magnetic component 82B in the second direction D2. This second recess 85 is recessed towards the side away from the magnetic component 82B in the second direction D2, and the magnetic component 82 contacts the second recess 85. According to this structure, by bringing the magnetic component 82 into contact with the second recess 85 of the magnet body 81B, the magnetic field of the magnet body 81B propagates efficiently to the magnetic component 82.

[0072] The above describes one embodiment and its variations of the present invention. However, the structures and combinations thereof in the embodiment and variations are merely examples, and additions, omissions, substitutions, and other changes to the structure are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiments described above.

[0073] For example, in the above embodiments (or variations thereof), the contact surfaces of the magnet bodies 81, 81B and the magnetic components 82, 82B are formed as planar surfaces, but this is not a limitation. For example, a recess may be provided on one of the contact surfaces of the magnet bodies 81, 81B and the magnetic components 82, 82B, and a protrusion that fits into the recess may be provided on the other contact surface of the magnet bodies 81, 81B and the magnetic components 82, 82B.

[0074] Alternatively, in the above-described embodiment (or its variations), the magnet portions 80 and 80B may also be embedded in the driven component 40. In this case, the magnet body 81 and the magnetic component 82 can be reliably fixed to the driven component 40.

[0075] Furthermore, while the electric actuator 10 is shown as a linear actuator that moves the driven object in the first direction D1, a more specific mechanism for moving the driven component 40 in the first direction D1 could also be a ball screw mechanism, a rack and pinion mechanism, etc. Additionally, to enable the driven component 40 to move in the first direction D1, magnets 80 and 80B could be provided on cylinders, hydraulic cylinders, etc.

[0076] Note that this technology can be configured as follows.

[0077] (1) An electric actuator comprising: a driven component that is reciprocated in a first direction; a magnet portion fixed to the driven component; and a magnetic sensor disposed opposite to the magnet portion in a second direction intersecting the first direction and detecting magnetic flux of the magnet portion, the magnet portion having: a magnet body made of a permanent magnet with the first direction as the magnetization direction; and a magnetic component made of a magnetic material connected to the magnet body and extending along the first direction, being longer than the magnet body in the first direction.

[0078] (2) In the electric actuator described in (1), the magnetic component has a first recess on the side opposite to the magnet body in the second direction, the first recess is recessed in the second direction away from the magnet body, and the magnet body is in contact with the first recess.

[0079] (3) In the electric actuator described in (1) or (2), the magnet body has a second recess on the side opposite to the magnetic component in the second direction, the second recess is recessed in the second direction toward the side away from the magnetic component, and the magnetic component is in contact with the second recess.

[0080] (4) In any of (1) to (3) the contact surface between the magnetic component and the magnet body is planar.

[0081] (5) In any of (1) to (4) of the electric actuator, the magnetic component is disposed relative to the magnet body on the side of the magnetic sensor in the second direction.

[0082] (6) In any of (1) to (5) the electric actuator, the magnet body is disposed at the center of the magnetic component in the first direction.

[0083] (7) In any of (1) to (6) of the electric actuators, the magnetic component is cylindrical and extends in the first direction.

[0084] (8) In any of (1) to (7) the electric actuator, the driven component is made of a non-magnetic material or a material that is less magnetic than the magnetic component.

[0085] Symbol Explanation

[0086] 10…electric actuator, 40…driven component, 71…magnetic sensor, 80, 80B…magnet part, 81, 81B…magnet body, 82, 82B…magnetic component, 83, 84…first recess, 83f, 84f…contact surface, 85…second recess.

Claims

1. An electric actuator, characterized by Possessing: a driven member that is driven reciprocally in a first direction; a magnet portion that is fixed to the driven member; and a magnetic sensor that is disposed opposite the magnet portion in a second direction that intersects the first direction, and detects a magnetic flux of the magnet portion, the magnet portion has: a magnet main body that is composed of a permanent magnet, with the first direction as a magnetization direction; and a magnetic member that is composed of a magnetic material, connected to the magnet main body and extending in the first direction, and longer than the magnet main body in the first direction.

2. The electric actuator according to claim 1, wherein: the magnetic member has a first recessed portion on a side opposite the magnet main body in the second direction, the first recessed portion being recessed toward a side away from the magnet main body in the second direction, the magnet main body is in contact with the first recessed portion.

3. The electric actuator according to claim 1 or 2, wherein: the magnet main body has a second recessed portion on a side opposite the magnetic member in the second direction, the second recessed portion being recessed toward a side away from the magnetic member in the second direction, the magnetic member is in contact with the second recessed portion.

4. The electric actuator according to claim 1 or 2, wherein: a contact surface of the magnetic member with the magnet main body is planar.

5. The electric actuator according to claim 1 or 2, wherein: the magnetic member is disposed on a side close to the magnetic sensor in the second direction with respect to the magnet main body.

6. The electric actuator according to claim 1 or 2, wherein: the magnet main body is disposed at a central portion of the magnetic member in the first direction.

7. The electric actuator according to claim 1 or 2, wherein: the magnetic member is cylindrical and extends in the first direction.

8. The electric actuator according to claim 1 or 2, wherein: the driven member is composed of a non-magnetic material or a material that is less magnetic than the magnetic member. ​

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