JP2020108319A - Electric actuator - Google Patents

Abstract

To provide an electric actuator capable of making a magnet, and thereby the electric actuator compact, and capable of detecting a turning angle of an output shaft stably and accurately.SOLUTION: An electric actuator 10 includes a motor, an output shaft 41 being connected with the motor, rotating in a rotation range α of 0°-360°around the axis line with the operation of the motor, and outputting power of the motor, a first magnet 63 being attached to the output shaft 41, rotating around the medial axis J1 together with the output shaft 41, and when being viewed from the medial axis J1 direction, having an arc shape where the central angle around the medial axis J1 is β, and provided with an N-pole at one end side and an S-pole at the other end side, and a first rotation sensor 61 placed to overlap with the first magnet 63 when being viewed from the medial axis J1 direction, and detecting a change in a flux density due to rotation of the first magnet 63.SELECTED DRAWING: Figure 6

Description

The present invention relates to an electric actuator.

Conventionally, as a drive source of a wiper device mounted on an automobile, for example, a motor with a speed reducer described in Patent Document 1 is known. This motor with a speed reducer includes an electric motor and a speed reducer connected to the electric motor. The speed reducer can reduce the output of the electric motor at a predetermined reduction ratio and output the output from the output shaft.

Further, the motor with a speed reducer described in Patent Document 1 includes a rotational position detection sensor that detects the rotational position of the output shaft, that is, the rotational angle. The rotational position detection sensor includes an annular sensor magnet that is arranged concentrically with the output shaft and rotates with the output shaft, and a magnetic sensor that is arranged apart from the sensor magnet and is fixed to, for example, a case. ing. The magnetic sensor outputs a detection signal when the sensor magnet rotates and the magnetic pole of the portion facing the magnetic sensor changes.

JP, 2011-244562, A

The sensor magnet of the motor with a reduction gear described in Patent Document 1 is a ring magnet formed in an annular shape. Further, this motor with a reducer is used as a drive source for a wiper device of an automobile, and in this case, the rotation range of the output shaft is 0° or more and 180° or less at most. Therefore, the annular sensor magnet has a portion that does not contribute to the detection of the rotation angle of the output shaft, which is wasteful. Then, the sensor magnet becomes large due to the useless portion. Further, since the sensor magnet is large, a detection error may occur, and as a result, the rotation angle of the output shaft may not be accurately detected.

An object of the present invention is to reduce the size of the magnet, and thus the size of the electric actuator, and to detect the rotation angle of the output shaft in a stable and accurate manner. It is to provide an actuator.

One mode of an electric actuator of the present invention is to connect a motor and a motor, and to rotate the motor in a rotation range α of more than 0° and less than 360° around the axis line to drive the power of the motor. An output output shaft and an output shaft that is attached to the output shaft, rotates around the axis together with the output shaft, and has an arc shape with a central angle of β centered on the axis when viewed from the axial direction, and has an N pole on one end side. And a detection element for detecting a change in magnetic flux density due to rotation of the magnet, the magnet having an S pole arranged on the other end side and the magnet arranged so as to overlap with the magnet when viewed from the axial direction. ..

According to the present invention, it is possible to reduce the size of the magnet and to detect the rotation angle of the output shaft in a stable and accurate manner.

FIG. 1 is a cross-sectional view showing an embodiment of the electric actuator of the present invention. FIG. 2 is a sectional view taken along line II-II in FIG. FIG. 3 is a partially enlarged view of the electric actuator shown in FIG. FIG. 4 is a perspective view of a part of the electric actuator shown in FIG. 1 viewed from below. FIG. 5 is a perspective view of a part of the electric actuator shown in FIG. 1 viewed from below. FIG. 6 is a plan view of the magnetic sensor of the electric actuator shown in FIG. 1 viewed from below. FIG. 7 is a sectional view taken along line VII-VII in FIG. FIG. 8 is a graph showing the relationship between the rotation angle and the magnetic flux density in the magnetic sensor shown in FIG. FIG. 9 is a graph obtained by enlarging a part of the graph shown in FIG.

Hereinafter, the electric actuator of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.
An embodiment of an electric actuator of the present invention will be described with reference to FIGS. In each drawing, the Z-axis direction is a vertical direction in which the positive side is the upper side and the negative side is the lower side. The axial direction of the central axis (axis) J1 shown in each drawing is parallel to the Z-axis direction, that is, the vertical direction. In the following description, the direction parallel to the axial direction of the central axis J1 is simply referred to as "axial direction Z". Further, the X-axis direction and the Y-axis direction that are shown in each drawing as appropriate are horizontal directions orthogonal to the axial direction Z and are directions orthogonal to each other. In the following description, the direction parallel to the X-axis direction is referred to as “first direction X”, and the direction parallel to the Y-axis direction is referred to as “second direction Y”.

Further, the radial direction around the central axis J1 is simply referred to as “radial direction”, and the circumferential direction around the central axis J1 is simply referred to as “circumferential direction”. In the present embodiment, the upper side corresponds to the other side in the axial direction, and the lower side corresponds to the one side in the axial direction. Note that the up-down direction, the horizontal direction, the upper side, and the lower side are merely names for explaining the relative positional relationship of each part, and the actual layout relationship and the like are layout relationships other than the layout relationship and the like indicated by these names. And so on.

As shown in FIG. 1, the electric actuator 10 of the present embodiment includes a case 11, a bearing holder 100, a motor 20 having a motor shaft 21 extending in the axial direction Z of the central axis J1, a control unit 70, and a connector unit. 80, a reduction mechanism 30, an output unit 40, a wiring member 90, a rotation detection device 60, a first bearing 51, a second bearing 52, a third bearing 53, and a bush 54. The first bearing 51, the second bearing 52, and the third bearing 53 are, for example, ball bearings.

The case 11 houses the motor 20 and the speed reduction mechanism 30. The case 11 includes a motor case 12 that houses the motor 20 and a speed reduction mechanism case 13 that houses the speed reduction mechanism 30. The motor case 12 corresponds to the first case. The speed reduction mechanism case 13 corresponds to the second case. That is, the electric actuator 10 includes a motor case 12 as a first case and a speed reduction mechanism case 13 as a second case. The motor case 12 includes a case tube portion 12a, a wall portion 12b, a control board housing portion 12f, an upper lid portion 12c, a terminal holding portion 12d, and a first wiring holding portion 14. Each part of the motor case 12 is made of resin except for a metal member 110 described later.

The case tubular portion 12a has a cylindrical shape extending in the axial direction Z around the central axis J1. The case tube portion 12a opens on both sides in the axial direction Z. The case tube portion 12a has a first opening 12g that opens downward. That is, the motor case 12 has the first opening 12g. The case tubular portion 12a surrounds the motor 20 in the radial direction.
The wall portion 12b has an annular shape that extends radially inward from the inner peripheral surface of the case tubular portion 12a. The wall portion 12b covers an upper side of a later-described stator 23 of the motor 20. The wall portion 12b has a through hole 12h that penetrates the wall portion 12b in the axial direction Z. In the present embodiment, the through hole 12h has a circular shape centered on the central axis J1. The inner diameter of the through hole 12h is larger than the outer diameter of the holder cylinder portion 101 described later. The wall 12b has a resin wall main body 12i and a metal member 110 made of metal. The wall body 12i is an annular portion that extends radially inward from the inner peripheral surface of the case tube portion 12a.

The metal member 110 has an annular shape and has a female screw portion on its inner peripheral surface. The metal member 110 is, for example, a nut. The metal member 110 is embedded in the wall body 12i. More specifically, the metal member 110 is embedded in the radially inner edge of the wall body 12i. The metal member 110 is located at a position radially outward of the through hole 12h with respect to the radially inner surface thereof. The upper surface of the metal member 110 is located above the upper surface of the wall body 12i. The upper surface of the metal member 110 is a flat surface orthogonal to the axial direction Z. Although illustration is omitted, a plurality of metal members 110 are provided in the present embodiment. The plurality of metal members 110 are arranged at equal intervals over the circumference along the circumferential direction. For example, three metal members 110 are provided.

The control board housing part 12f is a part for housing a control board 71 described later. The control board housing portion 12f is arranged radially inside the upper portion of the case tube portion 12a. The bottom surface of the control board housing portion 12f is the top surface of the wall portion 12b. The control board housing portion 12f opens upward. The upper lid portion 12c is a plate-shaped lid that closes the upper end opening of the control board housing portion 12f. The terminal holding portion 12d projects radially outward from the case tubular portion 12a. The terminal holding portion 12d has a cylindrical shape that is open outward in the radial direction. The terminal holding portion 12d holds a terminal 81 described later.

The first wiring holding portion 14 projects radially outward from the case tubular portion 12a. In FIG. 1, the first wiring holding portion 14 projects from the case tubular portion 12a to the negative side in the first direction X. The first wiring holding portion 14 extends in the axial direction Z. The axial position of the upper end portion of the first wiring holding portion 14 is substantially the same as the axial position of the wall portion 12b. The circumferential position of the first wiring holding portion 14 is different from the circumferential position of the connector portion 80, for example.

The reduction gear mechanism case 13 is located below the motor case 12. The speed reduction mechanism case 13 includes a speed reduction mechanism case body 13i and a cylindrical member 16. In the present embodiment, the reduction mechanism case body 13i corresponds to the second case body. The deceleration mechanism case body 13i is made of resin. The speed reduction mechanism case body 13i includes a bottom wall portion 13a, a tubular portion 13b, a protruding tubular portion 13c, and a second wiring holding portion 15. The bottom wall portion 13a has an annular shape centered on the central axis J1. The bottom wall portion 13a covers the lower side of the reduction mechanism 30.

The tubular portion 13b has a cylindrical shape that protrudes upward from the radially outer edge portion of the bottom wall portion 13a. The cylindrical portion 13b opens upward. The upper end of the tubular portion 13b is in contact with and fixed to the lower end of the case tubular portion 12a. The protruding cylindrical portion 13c has a cylindrical shape that protrudes downward from the radially inner edge portion of the bottom wall portion 13a. The protruding cylindrical portion 13c opens on both sides in the axial direction.

The second wiring holding portion 15 projects radially outward from the tubular portion 13b. In FIG. 1, the second wiring holding portion 15 projects from the cylindrical portion 13b to the negative side in the first direction X, that is, the same side as the side on which the first wiring holding portion 14 projects. The second wiring holding unit 15 is arranged below the first wiring holding unit 14. The second wiring holding portion 15 is, for example, hollow and has a box shape that opens upward. The inside of the second wiring holding portion 15 is connected to the inside of the tubular portion 13b. The second wiring holding portion 15 has a bottom wall portion 15a and a side wall portion 15b. The bottom wall portion 15a extends radially outward from the bottom wall portion 13a. In FIG. 1, the bottom wall portion 15a extends from the bottom wall portion 13a to the negative side in the first direction X. The side wall portion 15b extends upward from the outer edge portion of the bottom wall portion 15a. In the present embodiment, the bottom wall portion 13a and the bottom wall portion 15a constitute the bottom portion 13j of the reduction gear mechanism case body 13i.

The cylindrical member 16 has a cylindrical shape extending in the axial direction Z. More specifically, the cylindrical member 16 has a multi-stage cylindrical shape centered on the central axis J1 and opening on both sides in the axial direction. The cylindrical member 16 is made of metal. In the present embodiment, the cylindrical member 16 is made of sheet metal. Therefore, the cylindrical member 16 can be manufactured by pressing a metal plate, and the manufacturing cost of the cylindrical member 16 can be reduced. In the present embodiment, the cylindrical member 16 is a non-magnetic material.

The cylindrical member 16 is embedded in the reduction mechanism case body 13i. The cylindrical member 16 has a large diameter portion 16a, an annular portion 16b, and a small diameter portion 16c. The large diameter portion 16 a is an upper portion of the cylindrical member 16. The large diameter portion 16a is embedded in the tubular portion 13b. The upper end of the inner peripheral surface of the large diameter portion 16a is exposed inside the reduction gear mechanism case 13. As shown in FIG. 2, the large-diameter portion 16a has a positioning recess 16d that is recessed radially outward on the inner peripheral surface. In FIG. 2, the deceleration mechanism case body 13i is not shown.

As shown in FIG. 1, the annular portion 16b is an annular portion extending radially inward from the lower end of the large diameter portion 16a. In the present embodiment, the annular portion 16b has an annular plate shape centered on the central axis J1. The annular portion 16b is arranged on the bottom wall portion 13a. In the present embodiment, the annular portion 16b is located on the upper surface of the bottom wall portion 13a. The radially outer edge of the annular portion 16b is embedded in the tubular portion 13b. A portion of the upper surface of the annular portion 16b, which is closer to the inner side in the radial direction, is exposed inside the reduction gear mechanism case 13. The annular portion 16b covers the lower side of the first magnet 63 described below.
The upper surface of the annular portion 16b is a flat surface orthogonal to the axial direction Z.

As shown in FIG. 3, the annular portion 16b has a second recess 16e that is recessed upward from the lower surface of the annular portion 16b. The second recess 16e is located on the negative side of the annular portion 16b in the first direction X. Although illustration is omitted, the inner edge of the second recess 16e has a rectangular shape extending in the radial direction when viewed in the axial direction Z. In the present embodiment, the second recess 16e extends in the first direction X. The second recess 16e is located below the first magnet 63. That is, the second recess 16e is located at a position overlapping the first magnet 63 when viewed along the axial direction Z. In the present embodiment, the radially inner end of the second recess 16e is located below the first magnet 63.

The second concave portion 16e is formed by pressing the annular portion 16b from the lower side toward the upper side and crushing it. Therefore, the portion of the annular portion 16b where the second recess 16e is provided is crushed and thinned. As a result, the portion of the annular portion 16b where the second recess 16e is provided has a smaller dimension in the axial direction Z than the other portions of the annular portion 16b.

As shown in FIG. 1, the small diameter portion 16c is the lower side portion of the cylindrical member 16. The small diameter portion 16c extends downward from the radially inner edge portion of the annular portion 16b. The outer diameter and inner diameter of the small diameter portion 16c are smaller than the outer diameter and inner diameter of the large diameter portion 16a. The small diameter portion 16c is fitted inside the protruding cylindrical portion 13c in the radial direction. A cylindrical bush 54 extending in the axial direction Z is arranged inside the small diameter portion 16c. The bush 54 is fitted in the small diameter portion 16c and fixed in the protruding cylindrical portion 13c. The bush 54 has a bush flange portion 54a that projects outward in the radial direction at the upper end portion. The bush flange portion 54a contacts the upper surface of the annular portion 16b. As a result, the bush 54 is prevented from coming off from the inside of the small diameter portion 16c to the lower side.

The speed reduction mechanism case 13 has a second opening 13h that opens upward. In the present embodiment, the second opening 13h is configured by the upper opening of the tubular portion 13b and the upper opening of the second wiring holding portion 15. The motor case 12 and the reduction gear mechanism case 13 are fixed to each other with the first opening 12g and the second opening 13h facing each other in the axial direction Z. In the state where the motor case 12 and the reduction gear mechanism case 13 are fixed to each other, the inside of the first opening 12g and the inside of the second opening 13h are connected to each other.

In the present embodiment, the motor case 12 and the speed reduction mechanism case 13 are each formed by insert molding, for example. The motor case 12 is made by insert molding using a metal member 110 and a first wiring member 91, which will be described later, of the wiring member 90 as an insert member. The deceleration mechanism case 13 is made by insert molding using a cylindrical member 16 and a second wiring member 92, which will be described later, of the wiring member 90 as an insert member.

As shown in FIG. 3, the case 11 has a first recess 17 located on the outer surface of the case 11. In the present embodiment, the first recess 17 is provided in the speed reduction mechanism case 13. More specifically, the first recess 17 is recessed upward from the lower surface of the bottom portion 13j. In the present embodiment, the first recess 17 is provided across the bottom wall portion 13a and the bottom wall portion 15a. The first recess 17 extends in the radial direction. In the present embodiment, the direction in which the first recess 17 extends is a direction parallel to the first direction X in the radial direction. In the present embodiment, the first recess 17 overlaps with the second recess 16e when viewed along the axial direction Z.

The first recess 17 has a first portion 17a that is recessed upward from the lower surface of the bottom portion 13j, and a second portion 17b that is recessed upward from the bottom surface of the first portion 17a. The bottom surface of the first portion 17a is a surface of the inner surface of the first portion 17a that faces downward. The bottom surface of the second portion 17b is a surface of the inner side surface of the second portion 17b that faces downward. In the present embodiment, the bottom surface of the first recess 17 is a surface of the inner surface of the first recess 17 that faces downward, and is configured by the bottom surface of the first portion 17a and the bottom surface of the second portion 17b.

As shown in FIGS. 4 and 5, the inner edge of the first portion 17a has a substantially rectangular shape that is long in the first direction X when viewed along the axial direction Z. The second portion 17b has a main body accommodation portion 17c, a terminal accommodation portion 17d, a first protrusion accommodation portion 18a, and a second protrusion accommodation portion 18b. The main body housing portion 17c is an end portion of the second portion 17b on the radially inner side in the first direction X. The main body housing portion 17c is provided on the bottom wall portion 13a. A sensor body 64, which will be described later, is housed in the body housing portion 17c. The inner edge of the main body housing portion 17c has a rectangular shape that is long in the first direction X when viewed along the axial direction Z. In the present embodiment, the main body accommodating portion 17c has substantially the same size as the second concave portion 16e when viewed along the axial direction Z, and substantially entirely overlaps the second concave portion 16e.

As shown in FIG. 5, the bottom surface 16f of the second recess 16e of the annular portion 16b is exposed in the main body accommodating portion 17c. The bottom surface 16f is a surface facing the lower side of the inner side surface of the second recess 16e. The bottom surface 16f constitutes the bottom surface of the main body accommodating portion 17c. That is, the bottom surface of the first recess 17 includes the bottom surface 16f of the second recess 16e. The bottom surface 16f is a flat surface orthogonal to the axial direction Z.

The terminal accommodating portion 17d is connected to the end of the main body accommodating portion 17c on the radially outer side in the first direction X. The terminal accommodating portion 17d is provided on the bottom wall portion 15a. The inner edge of the terminal accommodating portion 17d has a rectangular shape that is long in the second direction Y when viewed along the axial direction Z. The dimension of the terminal accommodating portion 17d in the second direction Y is larger than the dimension of the main body accommodating portion 17c in the second direction Y. The terminal accommodating portion 17d projects to both sides in the second direction Y from the body accommodating portion 17c.

The first protrusion accommodating portion 18a and the second protrusion accommodating portion 18b are connected to the main body accommodating portion 17c. The first protrusion accommodating portion 18a is provided on one side (+Y side) of the main body accommodating portion 17c in the second direction Y. The second protrusion accommodating portion 18b is provided on the other side (−Y side) in the second direction Y of the main body accommodating portion 17c. The bottom surface of the first projection housing portion 18a and the bottom surface of the second projection housing portion 18b are located below the bottom surface 16f of the main body housing portion 17c. The bottom surface of the first protrusion accommodating portion 18a is a surface of the inner side surface of the first protrusion accommodating portion 18a that faces downward. The bottom surface of the second protrusion accommodating portion 18b is the surface of the inner side surface of the second protrusion accommodating portion 18b that faces downward.

Two first protrusion accommodating portions 18a are provided apart from each other in the first direction X. Two second protrusion accommodating portions 18b are provided apart from each other in the first direction X. The distance between the two first protrusion accommodating portions 18a in the first direction X is smaller than the distance between the two second protrusion accommodating portions 18b in the first direction X. In the first direction X, the position of the first protrusion accommodating portion 18a and the position of the second protrusion accommodating portion 18b are different from each other.

More specifically, of the two second protrusion accommodating portions 18b, the second protrusion accommodating portion 18b located on the outer side in the radial direction is located radially outer than the two first protrusion accommodating portions 18a. Further, of the two second protrusion accommodating portions 18b, the second protrusion accommodating portion 18b located on the radially inner side is positioned on the radially inner side of the two first protrusion accommodating portions 18a.

As shown in FIG. 1, the bearing holder 100 is fixed to the motor case 12. The bearing holder 100 is made of metal. In this embodiment, the bearing holder 100 is made of sheet metal. Therefore, the bearing holder 100 can be manufactured by pressing a metal plate, and the manufacturing cost of the bearing holder 100 can be reduced. The bearing holder 100 has a tubular holder tubular portion 101 and a holder flange portion 102. In the present embodiment, the holder tubular portion 101 has a cylindrical shape centered on the central axis J1. The holder tube portion 101 holds the first bearing 51 inside in the radial direction. The holder tube portion 101 is inserted into the through hole 12h. The holder cylinder portion 101 projects from the inside of the control board housing portion 12f through the through hole 12h below the wall portion 12b.

The outer diameter of the holder cylinder portion 101 is smaller than the inner diameter of the through hole 12h. Therefore, at least a part of the radially outer surface of the holder tubular portion 101 in the circumferential direction is positioned at a position radially inward from the radially inner surface of the through hole 12h. In the example shown in FIG. 1, the radially outer surface of the holder tubular portion 101 is located at a position radially inwardly separated from the radially inner surface of the through hole 12h over the entire circumference.

In the present embodiment, the holder tubular portion 101 has an outer tubular portion 101a and an inner tubular portion 101b. The outer tubular portion 101a has a cylindrical shape that extends downward from the radially inner edge portion of the holder flange portion 102. The radially outer surface of the outer tubular portion 101a is the radially outer surface of the holder tubular portion 101. The inner tubular portion 101b has a cylindrical shape that extends upward from the lower end of the outer tubular portion 101a on the radially inner side of the outer tubular portion 101a. The radially outer surface of the inner tubular portion 101b contacts the radially inner surface of the outer tubular portion 101a. In this way, the strength of the holder tubular portion 101 can be improved by constructing the holder tubular portion 101 by overlapping the two tubular portions in the radial direction. The first bearing 51 is held inside the inner tubular portion 101b in the radial direction. The upper end of the inner tubular portion 101b is located above the first bearing 51. The upper end of the inner tubular portion 101b is located slightly below the upper end of the outer tubular portion 101a.

The holder flange portion 102 extends radially outward from the holder cylinder portion 101. In the present embodiment, the holder flange portion 102 extends radially outward from the upper end portion of the holder cylinder portion 101. The holder flange portion 102 has an annular plate shape centered on the central axis J1. The holder flange portion 102 is located above the wall portion 12b. The holder flange portion 102 is fixed to the wall portion 12b. As a result, the bearing holder 100 is fixed to the motor case 12.

In the present embodiment, the holder flange portion 102 is fixed to the wall portion 12b by a plurality of screw members that are fastened to the wall portion 12b in the axial direction Z. In the present embodiment, the screw member for fixing the holder flange portion 102 is tightened to the female screw portion of the metal member 110 of the wall portion 12b. Although illustration is omitted, for example, three screw members for fixing the holder flange portion 102 are provided.

The holder flange portion 102 fixed by the screw member contacts the upper surface of the metal member 110. More specifically, the peripheral portion of the penetrating portion of the lower surface of the holder flange portion 102 through which the screw member penetrates contacts the upper surface of the metal member 110. The holder flange portion 102 is located at a position apart from the wall body 12i to the upper side. Therefore, the holder flange portion 102 can be accurately positioned in the axial direction Z by the metal member 110. Further, it is possible to prevent the holder flange portion 102 from tilting with respect to the axial direction Z. In addition, the holder flange portion 102 does not directly contact the wall body 12i. Therefore, even if a difference in thermal deformation amount occurs between the resin wall main body 12i and the metal metal member 110 due to the difference in linear expansion coefficient, stress is applied to the wall main body 12i. Can be suppressed. This can prevent the wall body 12i from being damaged and the metal member 110 from coming off the wall body 12i.

The motor 20 has a motor shaft 21, a rotor body 22, and a stator 23. The motor shaft 21 rotates around the central axis J1. The motor shaft 21 is supported by the first bearing 51 and the second bearing 52 so as to be rotatable about the central axis J1. The first bearing 51 is held by the bearing holder 100 and rotatably supports a portion of the motor shaft 21 above the rotor body 22. The second bearing 52 rotatably supports the portion of the motor shaft 21 below the rotor body 22 with respect to the reduction gear mechanism case 13.

The upper end portion of the motor shaft 21 protrudes above the wall portion 12b through the through hole 12h. The motor shaft 21 has an eccentric shaft portion 21a centered on an eccentric shaft J2 that is eccentric with respect to the central axis J1. The eccentric shaft portion 21 a is located below the rotor body 22. The inner ring of the third bearing 53 is fitted and fixed to the eccentric shaft portion 21a.

The rotor body 22 is fixed to the motor shaft 21. Although not shown, the rotor body 22 has a cylindrical rotor core fixed to the outer peripheral surface of the motor shaft 21, and a magnet fixed to the rotor core. The stator 23 radially faces the rotor body 22 with a gap. The stator 23 surrounds the rotor body 22 on the radially outer side of the rotor body 22. The stator 23 has an annular stator core 24 that surrounds the rotor body 22 in the radial direction, an insulator 25 that is mounted on the stator core 24, and a plurality of coils 26 that are mounted on the stator core 24 via the insulator 25. The stator core 24 is fixed to the inner peripheral surface of the case tubular portion 12a. As a result, the motor 20 is held in the motor case 12.

The control unit 70 includes a control board 71, a second mounting member 73, a second magnet 74, and a second rotation sensor 72. That is, the electric actuator 10 includes the control board 71, the second mounting member 73, the second magnet 74, and the second rotation sensor 72.
The control board 71 has a plate shape extending in a plane orthogonal to the axial direction Z. The control board 71 is housed in the motor case 12. More specifically, the control board 71 is housed in the control board housing portion 12f and is arranged apart from the wall portion 12b at the upper side. The control board 71 is a board electrically connected to the motor 20. The coil 26 of the stator 23 is electrically connected to the control board 71. The control board 71 controls the current supplied to the motor 20, for example. That is, for example, an inverter circuit is mounted on the control board 71.

The second mounting member 73 has an annular shape centered on the central axis J1. The inner peripheral surface of the second mounting member 73 is fixed to the upper end of the motor shaft 21. The second mounting member 73 is arranged above the first bearing 51 and the bearing holder 100. The second mounting member 73 is, for example, a non-magnetic material. The second mounting member 73 may be a magnetic material.

The second magnet 74 has an annular shape centered on the central axis J1. The second magnet 74 is fixed to the upper end surface of the radially outer edge portion of the second mounting member 73. The method of fixing the second magnet 74 to the second mounting member 73 is not particularly limited, and is, for example, adhesive bonding. The second mounting member 73 and the second magnet 74 rotate together with the motor shaft 21. The second magnet 74 is arranged above the first bearing 51 and the holder tubular portion 101. The second magnet 74 has N poles and S poles that are alternately arranged along the circumferential direction.

The second rotation sensor 72 is a sensor that detects the rotation of the motor 20. The second rotation sensor 72 is attached to the lower surface of the control board 71. The second rotation sensor 72 faces the second magnet 74 in the axial direction Z via a gap. The second rotation sensor 72 detects the magnetic field generated by the second magnet 74. The second rotation sensor 72 is, for example, a Hall element. Although illustration is omitted, a plurality of, for example, three second rotation sensors 72 are provided along the circumferential direction. The second rotation sensor 72 can detect the rotation of the motor shaft 21 by detecting the change in the magnetic field generated by the second magnet 74 that rotates together with the motor shaft 21.

The connector portion 80 is a portion where connection with the electrical wiring outside the case 11 is performed. The connector portion 80 is provided on the motor case 12. The connector part 80 has the terminal holding part 12d and the terminal 81 described above. The terminal 81 is embedded and held in the terminal holding portion 12d. One end of the terminal 81 is fixed to the control board 71. The other end of the terminal 81 is exposed to the outside of the case 11 via the inside of the terminal holding portion 12d. In the present embodiment, the terminal 81 is, for example, a bus bar.

An external power source is connected to the connector section 80 via an electrical wiring (not shown). More specifically, an external power supply is attached to the terminal holding portion 12d, and the electrical wiring of the external power supply is electrically connected to the portion of the terminal 81 protruding into the terminal holding portion 12d. Accordingly, the terminal 81 electrically connects the control board 71 and the electrical wiring. Therefore, in the present embodiment, power is supplied from the external power source to the coil 26 of the stator 23 via the terminal 81 and the control board 71.

The reduction mechanism 30 is arranged radially outside a lower portion of the motor shaft 21. The speed reduction mechanism 30 is housed inside the speed reduction mechanism case 13. The reduction mechanism 30 is arranged between the bottom wall portion 13a and the annular portion 16b and the motor 20 in the axial direction Z. The reduction mechanism 30 has an external gear 31, a plurality of protrusions 32, an internal gear 33, and an output flange 42.

The externally toothed gear 31 has a substantially annular plate shape centered on the eccentric shaft J2 of the eccentric shaft portion 21a and extending in a plane orthogonal to the axial direction Z. As shown in FIG. 2, a gear portion is provided on the radially outer surface of the external gear 31. The external gear 31 is connected to the eccentric shaft portion 21 a via a third bearing 53. Thereby, the reduction mechanism 30 is connected to the lower portion of the motor shaft 21. The external gear 31 is fitted to the outer ring of the third bearing 53 from the outside in the radial direction. As a result, the third bearing 53 connects the motor shaft 21 and the external gear 31 so as to be relatively rotatable about the eccentric axis J2.

As shown in FIG. 1, the plurality of protrusions 32 protrude from the external gear 31 toward the output flange 42 in the axial direction Z. The protruding portion 32 has a cylindrical shape protruding downward. As shown in FIG. 2, the plurality of protrusions 32 are arranged along the circumferential direction. More specifically, the plurality of protrusions 32 are arranged at equal intervals over the entire circumference in the circumferential direction centered on the eccentric axis J2.

The internal gear 33 is fixed to surround the outside of the external gear 31 in the radial direction and meshes with the external gear 31. The internal gear 33 has an annular shape centered on the central axis J1. As shown in FIG. 1, the internal gear 33 is located radially inside the upper end of the cylindrical member 16. The internal gear 33 is fixed to the inner peripheral surface of the metallic cylindrical member 16. Therefore, the internal gear 33 can be firmly fixed to the reduction mechanism case 13 while the reduction mechanism case body 13i is made of resin. This can prevent the internal gear 33 from moving with respect to the reduction mechanism case 13, and can prevent the position of the internal gear 33 from shifting. In the present embodiment, the internal gear 33 is fixed to the inner peripheral surface of the large diameter portion 16a by press fitting. In this way, the reduction gear mechanism 30 is fixed to the inner peripheral surface of the cylindrical member 16 and held by the reduction gear mechanism case 13. As shown in FIG. 2, a gear portion is provided on the inner peripheral surface of the internal gear 33. The gear portion of the internal gear 33 meshes with the gear portion of the external gear 31. More specifically, the gear portion of the internal gear 33 partially meshes with the gear portion of the external gear 31.

The internal gear 33 has a positioning projection 33a that projects radially outward. The positioning protrusion 33a is fitted into the positioning recess 16d provided in the large diameter portion 16a. As a result, it is possible to prevent the positioning protrusion 33a from being caught in the positioning recess 16d and causing the internal gear 33 to rotate relative to the cylindrical member 16 in the circumferential direction.

The output flange portion 42 is a part of the output portion 40. The output flange portion 42 is located below the external gear 31. The output flange portion 42 has an annular plate shape that expands in the radial direction around the central axis J1. The output flange portion 42 extends radially outward from an upper end portion of the output shaft 41 described later. As shown in FIG. 1, the output flange portion 42 contacts the bush flange portion 54a from above.

The output flange portion 42 has a plurality of holes 42a. In the present embodiment, the plurality of holes 42a penetrate the output flange 42 in the axial direction Z. As shown in FIG. 2, the shape of the hole 42a viewed along the axial direction Z is circular. The inner diameter of the hole 42a is larger than the outer diameter of the protrusion 32. The plurality of protrusions 32 provided on the external gear 31 are inserted into the plurality of holes 42a, respectively. The outer peripheral surface of the protrusion 32 is inscribed in the inner peripheral surface of the hole 42a. The inner peripheral surface of the hole 42a supports the external gear 31 so as to be swingable around the central axis J1 via the protrusion 32. In other words, the plurality of protrusions 32 support the external gear 31 so as to be swingable about the central axis J1 via the inner surface of the hole 42a.

The output unit 40 is a unit that outputs the driving force of the electric actuator 10. As shown in FIG. 1, the output unit 40 is housed in the speed reduction mechanism case 13. The output part 40 has an output shaft 41 and an output flange part 42. That is, the electric actuator 10 includes the output shaft 41 and the output flange portion 42. In the present embodiment, the output unit 40 is a single member.

The output shaft 41 is connected to the motor 20. More specifically, the output shaft 41 extends in the axial direction Z of the motor shaft 21 below the motor shaft 21. The output shaft 41 has a cylindrical portion 41a and an output shaft main body portion 41b, and outputs the power of the motor 20. The cylindrical portion 41a has a cylindrical shape extending downward from the inner edge of the output flange portion 42. The cylindrical portion 41a has a cylindrical shape having a bottom portion and opening upward. The cylindrical portion 41a is fitted inside the bush 54 in the radial direction. As a result, the output shaft 41 is rotatably supported by the cylindrical member 16 via the bush 54. As described above, the reduction mechanism 30 is fixed to the cylindrical member 16. Therefore, the reduction gear mechanism 30 and the output shaft 41 can be supported together by the metal cylindrical member 16. Thereby, the reduction mechanism 30 and the output shaft 41 can be arranged with high axial accuracy.

The second bearing 52 is housed inside the cylindrical portion 41a. The outer ring of the second bearing 52 is fitted inside the cylindrical portion 41a. As a result, the second bearing 52 connects the motor shaft 21 and the output shaft 41 so that they can rotate relative to each other. The lower end of the motor shaft 21 is located inside the cylindrical portion 41a. The lower end surface of the motor shaft 21 faces the upper surface of the bottom of the cylindrical portion 41a with a gap.

The output shaft main body 41b extends downward from the bottom of the cylindrical portion 41a. In the present embodiment, the output shaft main body 41b has a cylindrical shape centered on the central axis J1. The outer diameter of the output shaft main body 41b is smaller than the outer diameter and the inner diameter of the cylindrical portion 41a. The lower end portion of the output shaft main body portion 41b projects below the projecting tubular portion 13c. Another member for outputting the driving force of the electric actuator 10 is attached to the lower end of the output shaft body 41b.

When the motor shaft 21 is rotated around the central axis J1, the eccentric shaft portion 21a revolves around the central axis J1 in the circumferential direction. The revolution of the eccentric shaft portion 21a is transmitted to the external gear 31 via the third bearing 53, and the external gear 31 has a position where the inner peripheral surface of the hole portion 42a and the outer peripheral surface of the protruding portion 32 are in contact with each other. While swinging. As a result, the position at which the gear portion of the external gear 31 and the gear portion of the internal gear 33 mesh with each other changes in the circumferential direction. Therefore, the rotational force of the motor shaft 21 is transmitted to the internal gear 33 via the external gear 31.

Here, in this embodiment, the internal gear 33 does not rotate because it is fixed. Therefore, the external gear 31 rotates around the eccentric shaft J2 by the reaction force of the rotational force transmitted to the internal gear 33. At this time, the direction of rotation of the external gear 31 is opposite to the direction of rotation of the motor shaft 21. The rotation of the external gear 31 about the eccentric axis J2 is transmitted to the output flange portion 42 via the hole 42a and the protrusion 32. As a result, the output shaft 41 rotates about the central axis J1. In this way, the rotation of the motor shaft 21 is transmitted to the output unit 40 via the speed reduction mechanism 30.

The rotation of the output shaft 41 is reduced by the reduction mechanism 30 with respect to the rotation of the motor shaft 21. Specifically, in the configuration of the speed reduction mechanism 30 of the present embodiment, the speed reduction ratio R of the rotation of the output shaft 41 with respect to the rotation of the motor shaft 21 is represented by R=−(N2−N1)/N2. The negative sign at the beginning of the expression representing the reduction ratio R indicates that the rotation direction of the output shaft 41 to be decelerated is opposite to the rotation direction of the motor shaft 21. N1 is the number of teeth of the external gear 31, and N2 is the number of teeth of the internal gear 33. As an example, when the number of teeth N1 of the external gear 31 is 59 and the number of teeth N2 of the internal gear 33 is 60, the reduction ratio R is -1/60.

As described above, according to the speed reduction mechanism 30 of the present embodiment, the speed reduction ratio R of the rotation of the output shaft 41 with respect to the rotation of the motor shaft 21 can be made relatively large. Therefore, the rotation torque of the output shaft 41 can be made relatively large. In this way, the output shaft 41 can reduce the power of the motor 20 and output it. Accordingly, the electric actuator 10 can be used as a speed reducer, and thus, for example, the electric actuator 10 can be used as a drive source of a wiper device mounted on an automobile.
The wiring member 90 is electrically connected to the first rotation sensor 61 described later. In the present embodiment, the wiring member 90 is a member for connecting the first rotation sensor 61 of the rotation detection device 60 and the control board 71 of the control unit 70. In the present embodiment, the wiring member 90 is an elongated, plate-shaped bus bar. Although illustration is omitted, three wiring members 90 are provided in the present embodiment. Each wiring member 90 is configured by connecting a first wiring member 91 and a second wiring member 92.

The first wiring member 91 extends from the inside of the second wiring holding portion 15 to the inside of the control board housing portion 12f. Part of the first wiring member 91 is embedded in the first wiring holding portion 14, the case cylinder portion 12a, and the wall portion main body 12i. As a result, the first wiring member 91 is held by the motor case 2.

The lower end portion 91 a of the first wiring member 91 projects downward from the first wiring holding portion 14 and is located inside the second wiring holding portion 15. The upper end portion 91b of the first wiring member 91 protrudes upward from the wall body 12i and is connected to the control board 71. As a result, the first wiring member 91 is electrically connected to the control board 71, and is electrically connected to the electrical wiring outside the case 11 via the connector portion 80.

Part of the second wiring member 92 is embedded in the bottom portion 13j. As a result, the second wiring member 92 is held by the speed reduction mechanism case 13. The upper end portion 92a of the second wiring member 92 projects upward from the bottom wall portion 15a. The upper end portion 92a of the second wiring member 92 is connected to the lower end portion 91a of the first wiring member 91. The lower end portion 92b of the second wiring member 92 penetrates the bottom portion 13j and projects into the first recess 17. The lower end portion 92b corresponds to one end portion of the wiring member 90. As a result, the wiring member 90 penetrates the case 11 from the inside of the case 11 and has one end protruding into the inside of the first recess 17. As shown in FIGS. 4 and 5, the lower end portion 92b projects from the bottom surface of the terminal accommodating portion 17d into the terminal accommodating portion 17d.

The rotation detection device 60 detects the rotation of the output unit 40. As shown in FIG. 3, the rotation detection device 60 includes a first magnet 63, a covering portion 62, and a first rotation sensor 61. The first magnet 63 is attached to the output unit 40. More specifically, the first magnet 63 is fixed to the lower surface of the output flange portion 42. Accordingly, when the output shaft 41 rotates about the central axis J1, the first magnet 63 can rotate about the central axis J1 together with the output shaft 41. The first magnet 63 is located below the protrusion 32. The lower end of the first magnet 63 faces the upper side of the annular portion 16b with a gap.

The first rotation sensor 61 is located inside the first recess 17. The first rotation sensor 61 is a magnetic sensor that detects a magnetic field generated by the first magnet 63, that is, a detection element. The first rotation sensor 61 is located below the first magnet 63 with the annular portion 16b interposed therebetween. As a result, the first rotation sensor 61 is placed so as to overlap the magnet 63 when viewed from the central axis J1 direction. Then, when the first magnet 63 rotates together with the output shaft 41, the first rotation sensor 61 can detect a change in magnetic flux density (magnetic field) due to the rotation.

Here, as the magnetic flux density detectable by the first rotation sensor 61, there are a magnetic flux density Bz(Sin) in the central axis J1 (Z axis) direction and a magnetic flux density By(Cos) in the circumferential direction of the first magnet 63. is there. In the electric actuator 10, the first rotation sensor 61 detects the two-phase signal of the magnetic flux density Bz and the magnetic flux density By, and calculates the arctangent (Sin/Cos=ATAN) value to rotate the output shaft 41. The angle can be detected (see FIG. 8). In FIG. 8, the graph of the magnetic flux density Bz is shown as “axial magnetic flux”, the graph of the magnetic flux density By is shown as “circumferential magnetic flux”, and the graph of the arctangent value is shown as “ATAN”. Has been done. Further, in FIG. 8, a graph of an ideal (theoretical) relationship between the arctangent value and the rotation angle is also shown as the “sensor output ideal line”.

Such a first rotation sensor 61 is, for example, a Hall element. Further, according to the present embodiment, the cylindrical member 16 is a non-magnetic material. Therefore, even if the cylindrical member 16 is located between the first magnet 63 and the first rotation sensor 61, it is possible to prevent the detection accuracy of the magnetic field of the first magnet 63 by the first rotation sensor 61 from decreasing.
As shown in FIG. 4, the first rotation sensor 61 has a sensor body 64, a first protrusion 65a and a second protrusion 65b, and a plurality of sensor terminals 66a, 66b, 66c. The sensor body 64 has a substantially rectangular parallelepiped shape that extends in the first direction X and is flat in the axial direction Z. The sensor body 64 is housed in the first recess 17. More specifically, the sensor body 64 is housed in the body housing portion 17c. The sensor body 64 has an inner portion 64a, an outer portion 64b, and a connecting portion 64c. The inner portion 64a has a substantially square shape when viewed along the axial direction Z. The inner portion 64a has a sensor chip 64d therein.

As shown in FIG. 3, the sensor chip 64d is located below the first magnet 63. The sensor chip 64d detects the magnetic field generated by the first magnet 63. The first rotation sensor 61 can detect the rotation of the output unit 40 by using the sensor chip 64d to detect the change in the magnetic field generated by the first magnet 63 rotating with the output unit 40.

The outer portion 64b is located radially outside the inner portion 64a. The outer portion 64b has a substantially square shape when viewed along the axial direction Z. The outer portion 64b contacts the bottom surface 16f of the second recess 16e. That is, the first rotation sensor 61 contacts the bottom surface of the second recess 16e. Therefore, the first rotation sensor 61 can be positioned in the axial direction Z by the metal cylindrical member 16. Accordingly, the first rotation sensor 61 can be arranged with high positional accuracy. As shown in FIG. 4, sensor terminals 66a, 66b, 66c are held on the outer portion 64b. The connecting portion 64c connects the inner portion 64a and the outer portion 64b. The connection portion 64c electrically connects the sensor chip 64d and the sensor terminals 66a, 66b, 66c.

The first protrusion 65a and the second protrusion 65b protrude from the sensor body 64 in the second direction Y orthogonal to the axial direction Z. The first protrusion 65a projects from the sensor body 64 to one side (+Y side) in the second direction Y. The second projecting portion 65b projects from the sensor body 64 to the other side (−Y side) in the second direction Y. The first projecting portion 65a and the second projecting portion 65b have a plate shape whose plate surface is orthogonal to the axial direction Z.

Two first protrusions 65a are provided apart from each other in the first direction X. Two second protrusions 65b are provided apart from each other in the first direction X. The two first protrusions 65a are located inside the two first protrusion accommodating portions 18a, respectively. The two second protrusions 65b are located inside the two second protrusion accommodating portions 18b, respectively.

The sensor terminals 66a, 66b, 66c extend from the sensor body 64 radially outward. The sensor terminals 66a, 66b, 66c are housed in the terminal housing portion 17d. The sensor terminals 66a, 66b, 66c are electrically connected to the sensor chip 64d via the connection portion 64c. The plurality of sensor terminals 66a, 66b, 66c are arranged side by side along the second direction Y. The sensor terminal 66b is arranged between the sensor terminal 66a and the sensor terminal 66c in the second direction Y. The sensor terminal 66b extends linearly along the first direction X. The sensor terminals 66a and 66c include a first bent portion that is bent outward from the sensor body 64 in the second direction Y and away from the sensor terminal 66b, and a sensor terminal 66b that is radially outward of the first bent portion. And a second bent portion that bends to the side.

The sensor terminals 66a, 66b, 66c are connected to the lower end portions 92b of the second wiring members 92, respectively. As a result, the first rotation sensor 61 is connected to one end of the wiring member 90. In the present embodiment, the lower end portion 92b is bifurcated, and the sensor terminals 66a, 66b, 66c are sandwiched and held by the lower end portion 92b. The sensor terminals 66a, 66b, 66c are fixed to the lower end portion 92b by welding.

As described above, according to the present embodiment, the first rotation sensor 61 can be connected to the wiring member 90 in the first recess 17 located on the outer surface of the case 11. Therefore, a space for connecting the sensor terminals 66a, 66b, 66c of the first rotation sensor 61 and the wiring member 90 can be secured outside the case 11. As a result, as compared with the case where the first rotation sensor 61 is provided inside the case 11, the work required to connect the sensor terminals 66a, 66b, 66c and the wiring member 90 can be reduced. Therefore, it is possible to reduce the labor for disposing the first rotation sensor 61 and improve the productivity of the electric actuator 10.

Further, according to the present embodiment, the output unit 40 is housed in the reduction gear mechanism case 13, and the first recess 17 is provided in the reduction gear mechanism case 13. Therefore, the first rotation sensor 61 can be easily brought close to the output unit 40, and the rotation of the output unit 40 can be easily detected by the first rotation sensor 61.
Further, according to the present embodiment, the reduction gear mechanism case 13 has the cylindrical member 16 embedded in the reduction gear mechanism case 13. Therefore, when the first rotation sensor 61 is arranged inside the speed reduction mechanism case 13, the work of connecting the sensor terminals 66a, 66b, 66c and the wiring member 90 is more difficult to perform because the cylindrical member 16 interferes. Therefore, the effect of reducing the labor required for connecting the sensor terminals 66a, 66b, 66c and the wiring member 90 described above is particularly useful in the configuration in which the cylindrical member 16 is provided.

As shown in FIG. 3, at least a part of the first rotation sensor 61 is located inside the second recess 16e. Therefore, the position of the first rotation sensor 61 in the axial direction Z can be set closer to the first magnet 63 with the position thereof set higher. Thereby, the detection accuracy of the magnetic field of the first magnet 63 by the first rotation sensor 61 can be improved.

Further, for example, when the dimension in the axial direction Z of the portion of the annular portion 16b where the second concave portion 16e is provided is the same as the dimension in the axial direction Z of the other portion of the annular portion 16b, the annular portion 16b is 2 Projects upward at the portion where the concave portion 16e is provided. Therefore, the protruding annular portion 16b becomes closer to the first magnet 63, and the annular portion 16b and the first magnet 63 may come into contact with each other. On the other hand, according to the present embodiment, the portion of the annular portion 16b where the second recess 16e is provided has a smaller dimension in the axial direction Z than the other portions of the annular portion 16b. Therefore, as in the present embodiment, the second recess 16e can be provided while the upper surface of the annular portion 16b is a flat surface. As a result, it is possible to provide the second recess 16e and bring the first rotation sensor 61 close to the first magnet 63 while suppressing the contact of the annular portion 16b with the first magnet 63.

In the present embodiment, the upper end of the inner portion 64a and the upper end of the outer portion 64b of the first rotation sensor 61 are located inside the second recess 16e. By locating a part of the inner portion 64a inside the second recess 16e, the sensor chip 64d provided inside the inner portion 64a can be brought closer to the first magnet 63, and the detection of the first rotation sensor 61 can be performed. The accuracy can be improved more suitably.

The covering portion 62 is located inside the first recess 17. In the present embodiment, the covering portion 62 is filled inside the first recess 17. The covering portion 62 is made of resin. The lower end portion 92b of the second wiring member 92, that is, the one end portion of the wiring member 90 and the first rotation sensor 61 are embedded and covered by the covering portion 62. Therefore, it is possible to prevent moisture or the like from contacting the one end of the wiring member 90 located in the first recess 17 and the first rotation sensor 61.

As described above, the external gear 31 rotates about the central axis J1 by the operation of the motor 20. Further, along with this, the output shaft 41 can also rotate around the central axis J1. In the present embodiment, as shown in FIG. 6, the output shaft 41 is set to rotate (swing) about the central axis J1 within the rotation range α. The rotation range α is more than 0° and less than 360°, preferably 10° or more and 180° or less, more preferably 15° or more and 120° or less, but in the present embodiment, about 30°. Has become.

Therefore, when detecting the rotation angle of the output shaft 41, the first magnet 63 whose change in magnetic flux density is detected by the first rotation sensor 61 does not need to be annular with the central axis J1 as the center.
Therefore, in the present invention, as shown in FIG. 6, the first magnet 63 is configured by an arc-shaped magnet having a central angle β with the central axis J1 as the center when viewed from the central axis J1 direction. In the configuration shown in FIGS. 6 and 7, the first magnet 63 has the N pole arranged on one end side (that is, the right side in the drawing) and the S pole arranged on the other end side (that is, the left side in the drawing). However, the positional relationship between the N pole and the S pole is not limited to this, and the right and left may be reversed.

In this way, the first magnet 63 has a configuration in which the outer shape is an arc shape, and a part that contributes to the detection of the rotation angle of the output shaft 41 is left and the other useless parts are omitted. As a result, the size of the first magnet 63 and the size of the electric actuator 10 can be reduced as compared with the case where the first magnet 63 is formed in the annular shape as described above.

Further, if the first magnet 63 has a useless portion (that is, if the first magnet 63 has an annular shape), the first rotation sensor 61 is likely to cause a detection error due to the influence of the magnetic field (magnetic force) from the portion. As a result, the rotation angle of the output shaft 41 may not be accurately detected. On the other hand, in the electric actuator 10, the first rotation sensor 61 has a configuration in which a useless part is omitted. As a result, the first rotation sensor 61 is prevented or suppressed from being affected by the magnetic field from the useless portion, so that the rotation angle of the output shaft 41 can be stably and accurately detected.

Further, as described above, the rotation range α is preferably 10° or more and 180° or less. The central angle β of the first magnet 63 (arcuate shape) can be determined to a preferable size in accordance with the size of the rotation range α.
Then, the output shaft 41 rotates (swings) within such a rotation range α. As shown in FIG. 9, assuming the regression line of the ATAN graph within the range of 60° or more and 120° or less (rotation range α), the slope of the regression line is close to the slope of the ideal sensor output line. Accordingly, the rotation angle of the output shaft 41 can be detected more accurately by the first rotation sensor 61 within the range of 60° or more and 120° or less (rotation range α).

As shown in FIG. 6, the central angle β of the first magnet 63 is preferably larger than the rotation range α. Accordingly, the rotation angle of the output shaft 41 can be stably and accurately detected regardless of the size of the rotation range α.
In particular, the central angle β is preferably 1.2 times or more and 4 times or less, and more preferably 2.5 times or more and 3.5 times or less of the rotation range α. As a result, the rotation angle of the output shaft 41 can be detected more stably and reliably without excess or deficiency.
As the combination of the rotation range α and the central angle β, a combination of the rotation range α of about 10 to 30° and the center angle β of about 40 to 120° is preferable, and the rotation range α is about 30° and the center angle β. Is more preferably about 90°.

As shown in FIG. 6, the first rotation sensor 61 is arranged to face the first magnet 63 regardless of the rotation angle of the output shaft 41. Further, when the home position of the output shaft 41 is the position where the clockwise rotation angle in FIG. 6 and the counterclockwise rotation angle in FIG. 6 are the same, the first rotation sensor 61 , The central axis α ₀ of the rotation range α orthogonal to the central axis J1 is overlapped. As a result, the rotation angle of the output shaft 41 can be detected more stably and accurately.

Further, when viewed from the direction of the central axis J1, it is preferable that the outer peripheral surface 631 of the first magnet 63 overlaps the outer peripheral surface 421 of the output flange portion 42, but the invention is not limited to this. That is, the curvature of the outer peripheral surface 631 of the first magnet 63 is preferably the same as the curvature of the outer peripheral surface 421 of the output flange portion 42, but is not limited thereto. For example, the outer peripheral surface 631 of the first magnet 63 may be located inside the outer peripheral surface 421 of the output flange portion 42.

Further, when viewed from the direction of the central axis J1, it is preferable that the width W ₆₃ of the first magnet ₆₃ is constant along the circumferential direction, but the width W ₆₃ is not limited to this. For example, the first magnet 63 may have a portion in which the width W ₆₃ changes along the circumferential direction.
As shown in FIG. 7, the thickness t ₆₃ of the first magnet 63 is preferably constant along the circumferential direction, but is not limited to this. For example, the first magnet 63 may have a portion in which the thickness t ₆₃ changes along the circumferential direction.

The electric actuator of the present invention has been described above with reference to the illustrated embodiment, but the present invention is not limited to this, and each unit constituting the electric actuator has an arbitrary configuration capable of exhibiting the same function. Can be replaced with In addition, any constituent may be added.

DESCRIPTION OF SYMBOLS 10... Electric actuator, 11... Case, 12... Motor case (1st case), 12a... Case cylinder part, 12b... Wall part, 12c... Top cover part, 12d... Terminal holding part, 12f... Control board accommodating part, 12g... 1st opening part, 12h... Through hole, 12i... Wall part main body, 13... Reduction mechanism case (2nd case), 13a... Bottom wall part, 13b... Cylindrical part, 13c... Projecting cylinder part, 13h... 2nd opening part , 13i... Reduction mechanism case body (second case body), 13j... Bottom portion, 14... First wiring holding portion, 15... Second wiring holding portion, 15a... Bottom wall portion, 15b... Side wall portion, 16... Cylindrical member, 16a... Large diameter part, 16b... Annular part, 16c... Small diameter part, 16d... Positioning recess, 16e... Second recess, 16f... Bottom surface, 17... First recess, 17a... First part, 17b... Second part, 17c...main body accommodating part, 17d...terminal accommodating part, 18a...first protrusion accommodating part, 18b...second protrusion accommodating part, 20...motor, 21...motor shaft, 21a...eccentric shaft part, 22...rotor body, 23... Stator, 24... Stator core, 25... Insulator, 26... Coil, 30... Reduction mechanism, 31... External gear, 32... Projection part, 33... Internal gear, 33a... Positioning convex part, 40... Output part, 41... Output Shaft, 41a... Cylindrical part, 41b... Output shaft body part, 42... Output flange part, 42a... Hole part, 421... Outer peripheral surface, 51... First bearing, 52... Second bearing, 53... Third bearing, 54... Bush, 54a... Bush flange part, 60... Rotation detecting device, 61... First rotation sensor (rotation sensor), 62... Cover part, 63... First magnet, 631... Outer peripheral surface, 64... Sensor body, 64a... Inner part , 64b... Outer part, 64c... Connection part, 64d... Sensor chip, 65a... First projection part, 65b... Second projection part, 66a... Sensor terminal, 66b... Sensor terminal, 66c... Sensor terminal, 70... Control part, 71... Control board, 72... 2nd rotation sensor, 73... 2nd attachment member, 74... 2nd magnet, 80... Connector part, 81... Terminal, 90... Wiring member, 91... 1st wiring member, 91a... Lower end part , 91b... Upper end portion, 92... Second wiring member, 92a... Upper end portion, 92b... Lower end portion, 100... Bearing holder, 101... Holder tubular portion, 101a... Outer tubular portion, 101b... Inner tubular portion, 102... Holder flange Department, 110 ... metal member, By a ... flux density, Bz ... flux density, J1 ... center axis (axis), J2 ... eccentric shaft, t _{63 ...} thickness, W _{63 ...} width, X ... first direction, Y ... first 2 directions, Z... axis Direction, α... Rotation range, α ₀ ... Center line, β... Center angle

Claims (7)

A motor,
An output shaft that is connected to the motor and that rotates with a rotation range α of more than 0° and less than 360° around the axis line with the operation of the motor to output the power of the motor;
It is attached to the output shaft, rotates around the axis together with the output shaft, has an arc shape with a central angle of β centering on the axis when viewed from the axial direction, and has an N pole on one end side. , A magnet having an S pole on the other end side,
An electric actuator, comprising: a detection element that is disposed so as to overlap with the magnet when viewed from the axial direction, and that detects a change in magnetic flux density due to rotation of the magnet. The electric actuator according to claim 1, wherein the detection element is arranged so as to overlap a center line of the rotation range α orthogonal to the axis. The electric actuator according to claim 1, wherein the central angle β is larger than the rotation range α. The electric actuator according to claim 3, wherein the central angle β is 1.2 times or more and 4 times or less of the rotation range α. The electric actuator according to any one of claims 1 to 4, wherein the rotation range α is 180° or less. The electric actuator according to any one of claims 1 to 5, wherein the rotation range α is 10° or more. The electric actuator according to any one of claims 1 to 6, wherein the output shaft decelerates and outputs the power of the motor.

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