Electric actuator

Abstract

To provide an electric actuator with a structure that allows for miniaturization. [Solution] The electric actuator comprises a motor having a rotor that rotates about a first central axis, a reduction mechanism connected to the rotor, a rotating member that rotates about a second central axis extending in the axial direction of the first central axis, to which the rotation of the rotor is transmitted via the reduction mechanism, a movable member that moves in the axial direction in conjunction with the rotation of the rotating member, and a case having a motor housing that houses the motor inside. The second central axis is positioned differently from the first central axis in the radial direction centered on the first central axis. The rotating member extends in the axial direction. The reduction mechanism is located on one side of the motor in the axial direction. The case has a support wall that supports the motor from one side in the axial direction between the motor and the reduction mechanism. The support wall has a bearing that rotatably supports the other end of the rotating member in the axial direction. At least a portion of the rotating member overlaps with the motor when viewed in the axial direction.

Description

Technical Field

[0001] The present invention relates to an electric actuator.

Background Art

[0002] An electric actuator that converts the rotation of a motor rotor into linear motion is known (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the electric actuator as described above, in order to increase the output of the linearly moving member, the rotation of the rotor may be transmitted to the moving member via a speed reduction mechanism. In this case, due to the provision of the speed reduction mechanism, there is a problem that the electric actuator becomes large-sized.

[0005] In view of the above circumstances, one object of the present invention is to provide an electric actuator having a structure that can be miniaturized.

Means for Solving the Problems

[0006] One embodiment of the electric actuator of the present invention comprises a motor having a rotor that rotates about a first central axis; a reduction mechanism connected to the rotor; a rotating shaft that rotates about a second central axis extending in the axial direction of the first central axis, to which the rotation of the rotor is transmitted via the reduction mechanism; a movable member that moves in the axial direction in conjunction with the rotation of the rotating shaft; and a case having a motor housing portion that houses the motor inside. The second central axis is positioned at a different location from the first central axis in the radial direction centered on the first central axis. The reduction mechanism is located on one axial side of the motor. The case has a support wall portion that supports the motor from one axial side between the motor and the reduction mechanism in the axial direction. The support wall portion has a bearing portion that rotatably supports the other axial end of the rotating shaft. At least a portion of the rotating shaft overlaps with the motor when viewed in the axial direction. [Effects of the Invention]

[0007] According to one aspect of the present invention, electric actuators can be miniaturized. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view showing an electric actuator in the first embodiment. [Figure 2] Figure 2 is a cross-sectional view showing an electric actuator in the first embodiment, and is a view showing the cross-section through which the second central axis passes. [Figure 3] Figure 3 is a cross-sectional view showing an electric actuator in the first embodiment, and is a diagram showing the cross-section through which the first central axis passes. [Figure 4] Figure 4 is a perspective view showing the actuator section in the first embodiment. [Figure 5] Figure 5 is a cross-sectional view showing a part of the electric actuator in the first embodiment, and is a VV cross-sectional view of Figure 3. [Figure 6] Figure 6 is a cross-sectional perspective view showing a part of the electric actuator in the first embodiment. [Figure 7] Figure 7 is an exploded perspective view showing the first cylindrical portion, the rotating member, and the moving member in the first embodiment. [Figure 8] Figure 8 is a cross-sectional view showing a part of the electric actuator in the first embodiment, and is a cross-sectional view taken along line VIII-VIII in Figure 2. [Figure 9] Figure 9 is an exploded perspective view showing a part of the electric actuator in the first embodiment. [Figure 10] Figure 10 is a perspective view showing the motor, retaining member, and elastic member in the first embodiment. [Figure 11] Figure 11 is an exploded perspective view showing a part of the electric actuator in the first embodiment, and shows a part that differs from Figure 9. [Figure 12] Figure 12 is a cross-sectional view showing a part of the electric actuator in the first embodiment, and is a cross-sectional view taken along line XII-XII in Figure 2. [Figure 13] Figure 13 is a cross-sectional view showing an electric actuator in the second embodiment. [Figure 14] Figure 14 is a cross-sectional view showing an electric actuator in the third embodiment. [Modes for carrying out the invention]

[0009] The drawings will, as appropriate, show a hypothetical first central axis J1 in the motor of the electric actuator described below. In the following description, unless otherwise specified, the axial direction of the first central axis J1 will simply be referred to as the "axial direction." The radial direction centered on the first central axis J1 will simply be referred to as the "radial direction." The Y-axis shown in each figure indicates the direction in which the first central axis J1 extends. The X-axis shown in each figure indicates one direction perpendicular to the Y-axis direction. The Z-axis shown in each figure indicates a direction perpendicular to both the X-axis direction and the Y-axis direction. In the following description, the direction along the X-axis will be referred to as the "width direction," and the direction along the Z-axis will be referred to as the "up and down direction." Furthermore, the side of the axial direction in which the Y-axis arrow points (+Y side) will be referred to as the "one axial side," and the side of the axial direction opposite to the side in which the Y-axis arrow points (-Y side) will be referred to as the "other axial side." In the width direction, the side where the X-axis arrow points (+X side) is called the "one side of the width direction," and the side opposite to the side where the X-axis arrow points (-X side) is called the "other side of the width direction." In the up and down direction, the side where the Z-axis arrow points (+Z side) is called the "up side," and the side opposite to the side where the Z-axis arrow points (-Z side) is called the "down side."

[0010] In the following embodiments, the axial direction (Y-axis direction) corresponds to a "predetermined direction". The vertical direction (Z-axis direction) corresponds to a "first direction" that intersects with the axial direction, the upper side (+Z side) corresponds to "one side of the first direction", and the lower side (-Z side) corresponds to "the other side of the first direction". The width direction (X-axis direction) corresponds to a "second direction" that is perpendicular to both the axial direction and the first direction. Note that the vertical direction, width direction, upper side, and lower side are merely names used to describe the relative positional relationship of each part, and the actual arrangement relationships may be other than those indicated by these names.

[0011] <First Embodiment> The electric actuator 100 shown in FIG. 1 is a linear actuator. In the present embodiment, the electric actuator 100 is an actuator capable of switching a flow path through which a fluid flows. The electric actuator 100 is mounted on a vehicle, for example. As shown in FIG. 1, the electric actuator 100 includes a case 10 and an actuator unit 100a. As shown in FIG. 2, the electric actuator 100 includes a pressing member 55, a substrate 56, a first seal member 80, a first spacer 81, a second spacer 82, a plate member 83, a second seal member 84, and a third seal member 85. As shown in FIG. 3, the electric actuator 100 includes an elastic member 54.

[0012] The actuator unit 100a can switch a flow path (not shown) by a moving member 72 that linearly moves in the axial direction. As shown in FIG. 1, in the present embodiment, the electric actuator 100 includes three actuator units 100a. The three actuator units 100a are arranged side by side at intervals in the width direction (X-axis direction). The structures of the three actuator units 100a are the same except for the positions where they are arranged. Note that the number of actuator units 100a provided in the electric actuator 100 is not particularly limited as long as it is one or more.

[0013] As shown in FIG. 2, the actuator unit 100a has a motor 50, a speed reduction mechanism 60, a rotating member 71, and a moving member 72. That is, the electric actuator 100 includes a motor 50, a speed reduction mechanism 60, a rotating member 71, and a moving member 72. In the present embodiment, the motor 50 is an inner rotor type motor. As shown in FIG. 3, the motor 50 has a motor housing 51, a rotor 52, and a stator 53.

[0014] The motor housing 51 houses the rotor 52 and the stator 53 inside. As shown in FIG. 4, the motor housing 51 has a cylindrical portion 51a, a plate-like portion 51b, and a supported portion 51d. The cylindrical portion 51a is cylindrical with the first central axis J1 as the center. The plate-like portion 51b is connected to the surface on one axial side (+Y side) of the cylindrical portion 51a. The plate-like portion 51b is plate-shaped with the plate surface facing the axial direction. The plate-like portion 51b is substantially rectangular when viewed in the axial direction. The plate-like portion 51b protrudes on both sides in the width direction (X-axis direction) from the cylindrical portion 51a.

[0015] The supported portion 51d protrudes from the plate-like portion 51b on one axial side (+Y side). In the present embodiment, the supported portion 51d is annular and surrounds the first central axis J1. More specifically, the supported portion 51d is annular with the first central axis J1 as the center. As shown in FIG. 3, the motor housing 51 has a convex portion 51c that protrudes axially from the surface on the other axial side (-Y side) of the cylindrical portion 51a. The convex portion 51c is disc-shaped with the first central axis J1 as the center.

[0016] The rotor 52 rotates around the first central axis J1. The rotor 52 has a motor shaft 52a and a rotor body 52b. The motor shaft 52a extends in the axial direction. The motor shaft 52a is cylindrical and extends axially with the first central axis J1 as the center. The motor shaft 52a is axially passed through the inner side in the radial direction of the supported portion 51d. The motor shaft 52a protrudes axially from the inside of the motor housing 51 to the outside of the motor housing 51 on one axial side (+Y side). The end on one axial side of the motor shaft 52a is located outside the motor housing 51. The rotor body 52b is fixed to the outer peripheral surface of the motor shaft 52a. Although not shown, the rotor body 52b has a rotor core and a rotor magnet. The stator 53 is located on the outer side in the radial direction of the rotor 52. The stator 53 surrounds the rotor body 52b.

[0017] The reduction gear 60 is connected to the rotor 52 of the motor 50. The reduction gear 60 is located on one axial side (+Y side) of the motor 50. As shown in Figure 4, in this embodiment, the reduction gear 60 has a first gear section 61 and a second gear section 62. The first gear section 61 rotates together with the rotor 52 around a first central axis J1. In this embodiment, the first gear section 61 is annular in shape surrounding the first central axis J1. The first gear section 61 has a plurality of teeth on its outer circumferential surface that are arranged in the circumferential direction around the first central axis J1. The portion of the motor shaft 52a located outside the motor housing 51 is fitted inside the first gear section 61. The first gear section 61 is fixed to the outer circumferential surface of the portion of the motor shaft 52a located outside the motor housing 51. In this way, the motor shaft 52a is connected to the reduction gear 60. Note that the first gear section 61 and the motor shaft 52a may be part of the same single component.

[0018] The second gear section 62 is located on one side (+X side) of the first gear section 61 in the width direction. The second gear section 62 meshes with the first gear section 61. The second gear section 62 rotates together with the rotating member 71 around the second central axis J2. The second central axis J2 is an imaginary line extending in the axial direction of the first central axis J1. The second central axis J2 is positioned differently from the first central axis J1 in the radial direction centered on the first central axis J1. As shown in Figure 5, in this embodiment, the second central axis J2 is located on one side of the width direction from the first central axis J1. The second central axis J2 is located below the first central axis J1. As shown in Figure 6, the second gear section 62 is an annular shape surrounding the second central axis J2. The outer diameter of the second gear section 62 is larger than the outer diameter of the first gear section 61. The second gear section 62 has multiple teeth on its outer circumferential surface, arranged in the circumferential direction around the second central axis J2. The teeth of the second gear section 62 mesh with the teeth of the first gear section 61.

[0019] As shown in Figure 7, in this embodiment, the rotating member 71 is a rotating shaft extending in the axial direction. The rotating member 71 is substantially cylindrical in shape and extends in the axial direction with respect to the second central axis J2. The rotating member 71 rotates around the second central axis J2. The rotating member 71 has a shaft body portion 71a and a supported shaft portion 71b. The shaft body portion 71a is substantially cylindrical in shape and extends in the axial direction. As shown in Figure 6, the shaft body portion 71a is passed axially inside the second gear portion 62. The outer circumferential surface of the shaft body portion 71a is fixed to the inner circumferential surface of the second gear portion 62. This connects the rotating member 71 to the reduction mechanism 60. The rotation of the rotor 52 is transmitted to the rotating member 71 via the reduction mechanism 60. The rotating member 71 rotates when the motor 50 is driven.

[0020] As shown in Figure 7, the supported shaft portion 71b is connected to the other axial end (-Y side) of the shaft body portion 71a. The outer diameter of the supported shaft portion 71b is smaller than the outer diameter of the shaft body portion 71a. The other axial end of the supported shaft portion 71b is the other axial end of the rotating member 71. The axial dimension of the supported shaft portion 71b is smaller than the axial dimension of the shaft body portion 71a. The supported shaft portion 71b is rotatably supported by the bearing portion 21e, which will be described later.

[0021] The rotating member 71 has a first threaded portion 71c on its outer circumferential surface. The first threaded portion 71c rotates around the second central axis J2 when the motor 50 is driven. In this embodiment, the first threaded portion 71c is provided on one axial side (+Y side) of the outer circumferential surface of the shaft body portion 71a. As shown in Figure 8, at least a part of the rotating member 71 overlaps with the motor 50 when viewed in the axial direction. In this embodiment, the center of the rotating member 71 through which the second central axis J2 passes overlaps with the motor 50 when viewed in the axial direction. In this embodiment, almost the entire rotating member 71, excluding the edge on one widthwise side (+X side), overlaps with the motor 50 when viewed in the axial direction.

[0022] As shown in Figure 2, the movable member 72 extends in the axial direction. The movable member 72 protrudes from the inside of the case 10 to the outside of the case 10 in one axial direction through an opening on one axial side (+Y side) of the first cylindrical portion 41, which will be described later. The movable member 72 has a second cylindrical portion 72a and a connected portion 72b. The second cylindrical portion 72a is a cylindrical portion that extends in the axial direction. The second cylindrical portion 72a opens on the other axial side (-Y side). The second cylindrical portion 72a is substantially cylindrical with a second central axis J2 as its center. The second cylindrical portion 72a has a second threaded portion 72c on its inner circumferential surface. In other words, the movable member 72 has a second threaded portion 72c. In this embodiment, the second threaded portion 72c is provided over almost the entire axial length of the inner circumferential surface of the second cylindrical portion 72a. At least a portion of the rotating member 71 is located inside the second cylindrical portion 72a. In this embodiment, one axial portion of the rotating member 71 is located inside the second cylindrical portion 72a. The other axial portion of the rotating member 71 is located on the other axial side of the second cylindrical portion 72a. The second threaded portion 72c provided on the inner circumferential surface of the second cylindrical portion 72a engages with the first threaded portion 71c provided on the outer circumferential surface of the rotating member 71.

[0023] The connected portion 72b is connected to one axial side (+Y side) of the second cylindrical portion 72a. A drive object, which is driven axially by the electric actuator 100, is connected to the connected portion 72b. This drive object is, for example, a spool valve for switching flow paths (not shown). The connected portion 72b is provided with a hole 72e that connects to the inside of the second cylindrical portion 72a.

[0024] As shown in Figure 7, a pair of flat surfaces 72d are provided on the outer circumferential surface of the movable member 72. The pair of flat surfaces 72d are arranged to sandwich the second central axis J2 in the width direction (X-axis direction). The pair of flat surfaces 72d extend in the axial direction. The portion of the outer circumferential surface of the movable member 72 other than the pair of flat surfaces 72d is a curved surface 72f that is arc-shaped with respect to the second central axis J2 when viewed in the axial direction.

[0025] When the rotating member 71 rotates around the second central axis J2, the first threaded portion 71c rotates, and the second threaded portion 72c, which engages with the first threaded portion 71c, is moved axially. As a result, the moving member 72 moves axially in conjunction with the rotation of the rotating member 71. The moving member 72 shown in Figures 1 to 3 is in the state where it is located furthest to the other axial side (-Y side).

[0026] As shown in Figure 1, the case 10 is a roughly rectangular box shape extending in the width direction (X-axis direction). The case 10 houses a plurality of actuator parts 100a inside. The case 10 has a case body 20, a first cover 30, and a second cover 40. In this embodiment, the case body 20, the first cover 30, and the second cover 40 are made of resin. However, the case body 20, the first cover 30, and the second cover 40 may be made of materials other than resin, such as metal. The case body 20 is a roughly rectangular box shape extending in the width direction. As shown in Figure 2, the case body 20 opens to the top. The case body 20 has a first case part 21, a second case part 22, and a substrate housing part 23. In other words, the case 10 comprises a first case part 21, a second case part 22, and a substrate housing part 23.

[0027] The first case section 21 is a roughly rectangular box shape that extends in the width direction (X-axis direction) and opens upward. The first case section 21 has a motor housing section 20a that houses the motor 50 inside. In other words, the case 10 has a motor housing section 20a. Although not shown in the figures, in this embodiment, three motor housing sections 20a are provided side by side in the width direction. Each of the three motor housing sections 20a houses one of the motors 50 of the three actuator sections 100a. The motor housing section 20a is a box shape that opens upward. The motor housing section 20a has a first opening 21i that opens upward. The first opening 21i is an opening large enough for the motor 50 to pass through in the vertical direction.

[0028] The motor housing 20a has a first bottom wall 21a, a first support wall 21b, a second support wall 21c, and a side wall 21d. In other words, the case 10 has a first bottom wall 21a, a first support wall 21b, a second support wall 21c, and a side wall 21d. The first bottom wall 21a is the lower wall portion of the walls constituting the motor housing 20a. The first support wall 21b is the wall portion of the walls constituting the motor housing 20a located on one axial side (+Y side). The second support wall 21c is the wall portion of the walls constituting the motor housing 20a located on the other axial side (-Y side). The side wall 21d is the wall portion of the walls constituting the motor housing 20a located on both sides in the width direction.

[0029] In this embodiment, the first support wall portion 21b is a support wall portion that supports the motor 50 from one axial side (+Y side) between the motor 50 and the reduction mechanism 60 in the axial direction. The motor 50 is in contact with the other axial side (-Y side) surface of the first support wall portion 21b. In this embodiment, the other axial side surface of the first support wall portion 21b is in contact with the axial side surface of the plate-shaped portion 51b of the motor housing 51.

[0030] The first support wall portion 21b has a bearing portion 21e that rotatably supports the other axial end (-Y side) of the rotating member 71. Therefore, the rotating member 71 can be rotatably supported using the first support wall portion 21b that supports the motor 50 in the axial direction. This eliminates the need to provide another wall portion or the like on one axial side (+Y side) of the first support wall portion 21b to support the rotating member 71. Therefore, the electric actuator 100 can be made smaller in the axial direction compared to cases where such another wall portion or the like is provided. Also, as described above, at least a part of the rotating member 71 supported by the bearing portion 21e overlaps with the motor 50 when viewed in the axial direction. Therefore, the electric actuator 100 can be made smaller in the radial direction compared to the case where the entire rotating member 71 is located radially outward from the motor 50. Thus, according to this embodiment, the electric actuator 100 can be made smaller in the axial and radial directions while providing a reduction mechanism 60.

[0031] Furthermore, as described above, in this embodiment, the first opening 21i of the motor housing 20a is sized to allow the motor 50 to pass through in the vertical direction. Therefore, the motor 50 can be positioned in the motor housing 20a from above through the first opening 21i. This makes the electric actuator 100 more compact in the axial direction compared to, for example, a structure in which the motor 50 is positioned and assembled in the motor housing 20a from one axial side or the other axial side.

[0032] Furthermore, as described above, in this embodiment, the reduction mechanism 60 is composed of two gear sections: a first gear section 61 and a second gear section 62. Therefore, the number of parts in the reduction mechanism 60 can be reduced, and the radial enlargement of the reduction mechanism 60 can be suppressed. Consequently, the number of parts in the electric actuator 100 can be reduced, and the electric actuator 100 can be made even smaller in the radial direction.

[0033] In this embodiment, the bearing portion 21e is formed by a hole that penetrates the first support wall portion 21b in the axial direction. As shown in Figure 5, the bearing portion 21e is circular in shape when viewed in the axial direction, with the second central axis J2 as the center. The supported shaft portion 71b of the rotating member 71 is fitted into the bearing portion 21e. As a result, the supported shaft portion 71b is supported by the bearing portion 21e so as to be rotatable around the second central axis J2. As shown in Figure 2, in this embodiment, the other axial side (-Y side) portion of the supported shaft portion 71b is fitted into the bearing portion 21e. The end on one axial side (+Y side) of the supported shaft portion 71b is located one axial side further to the bearing portion 21e. The other axial end of the supported shaft portion 71b is located one axial side further to the bearing portion 21e than the other axial end of the bearing portion 21e. The other axial opening of the bearing portion 21e is closed by the motor 50. More specifically, the axial opening on the other side of the bearing portion 21e is closed by the plate-shaped portion 51b of the motor housing 51. The axial end of the supported shaft portion 71b located within the bearing portion 21e faces the motor 50 with a gap between them.

[0034] As shown in Figure 3, an elastic member 54 is positioned inside the motor housing 20a. The elastic member 54 is located inside the motor housing 20a on the other axial side (-Y side) of the motor 50. The elastic member 54 sandwiches the motor 50 between itself and the first support wall 21b in the axial direction and contacts the motor 50 in an elastically deformed state. Therefore, the elastic member 54 can press the motor 50 against the first support wall 21b from the other axial side. This suppresses the axial movement of the motor 50 within the motor housing 20a. Consequently, the motor 50 is subjected to a force in one axial direction (+Y side) by the elastic member 54, suppressing axial rattle. By suppressing the axial rattle of the motor 50, the axial rattle of the first gear section 61 can also be suppressed. Since the axial rattle of the first gear section 61 relative to the second gear section 62 can be suppressed, uneven wear on the tooth surfaces of both gears and an increase in noise, vibration, and backlash can be suppressed, and axial rattle between the second gear section 62 and the rotating member 71 and the moving member 72 can be suppressed.

[0035] As shown in Figures 9 and 10, in this embodiment, the elastic member 54 is a sheet metal member. The elastic member 54 has a bottom plate portion 54a, a deformable portion 54b, and a contact portion 54d. The bottom plate portion 54a is plate-shaped with its surface facing vertically. In this embodiment, the bottom plate portion 54a is rectangular. As shown in Figure 3, the bottom plate portion 54a contacts the upper surface of the first bottom wall portion 21a. The bottom plate portion 54a is located below the motor 50. A gap is provided between the bottom plate portion 54a and the motor 50 in the vertical direction. The other axial end (-Y side) of the bottom plate portion 54a contacts the surface on one axial side (+Y side) of the second support wall portion 21c.

[0036] The deformable portion 54b extends upward from the other axial end (-Y side) of the bottom plate portion 54a. The deformable portion 54b is located on the other axial side of the motor 50. The deformable portion 54b is curved in a direction that is convex to one axial side in a cross section perpendicular to the width direction (X-axis direction). The deformable portion 54b is an elastically deformable portion in the axial direction. The surface of the deformable portion 54b on one axial side (+Y side) is in contact with the motor 50. More specifically, the central part in the vertical direction of the surface of the deformable portion 54b on one axial side is in contact with the surface of the cylindrical portion 51a of the motor housing 51 on the other axial side. The lower end and upper end of the deformable portion 54b are in contact with the surface of the second support wall portion 21c on one axial side.

[0037] As shown in Figure 10, a through hole 54c is provided in the vertical center of the deformable portion 54b, penetrating the deformable portion 54b axially. The protrusion 51c of the motor housing 51 is located in the through hole 54c. The through hole 54c is an elongated hole that is long in the vertical direction. Because the deformable portion 54b is curved in a direction that is convex in one axial direction, the upper end of the through hole 54c is open upward. As a result, when the motor 50 is inserted into the motor housing 20a from above with the elastic member 54 placed inside the motor housing 20a, the protrusion 51c of the motor 50 can be inserted into the through hole 54c from the upper end of the through hole 54c. Therefore, when the motor 50 is placed inside the motor housing 20a, contact between the protrusion 51c and the elastic member 54 can be suppressed, making it easier to place the motor 50 inside the motor housing 20a. Furthermore, since the deformable portion 54b can avoid contact with the convex portion 51c, the deformable portion 54b can be stably brought into contact with the cylindrical portion 51a of the motor housing 51. As a result, the deformable portion 54b can stably press the motor 50 against the first support wall portion 21b. Therefore, the deformable portion 54b applies a force to the motor 50 in one axial direction (+Y direction), and as described above, it is possible to suppress axial rattle of the motor 50, axial rattle of the first gear portion 61, and axial rattle between the second gear portion 62 and the rotating member 71 and the moving member 72.

[0038] When the motor 50 is in contact with the first support wall 21b, the axial gap between the motor 50 and the second support wall 21c is smaller than the axial dimension of the deformable portion 54b in its non-elastically deformed state. Therefore, when the motor 50 is inserted into the motor housing 20a from above with the elastic member 54 positioned inside the motor housing 20a, the deformable portion 54b is elastically deformed in a direction that is axially compressed by the motor 50 and the second support wall 21c. As a result, the deformable portion 54b contacts the motor 50 in an elastically deformed state, and the deformable portion 54b can apply a force to the motor 50 in one axial direction (+Y direction).

[0039] The contact portion 54d connects to the upper end of the deformable portion 54b. The contact portion 54d protrudes upward from the upper end of the deformable portion 54b. In this embodiment, the contact portion 54d is a rectangular plate that is long in the width direction (X-axis direction). The plate surface of the contact portion 54d is perpendicular to the axial direction. As shown in Figure 3, the contact portion 54d contacts the surface of the second support wall portion 21c on one axial side (+Y side).

[0040] As shown in Figure 9, the first support wall portion 21b has a through portion 21g that penetrates the first support wall portion 21b in the axial direction. In this embodiment, the through portion 21g extends in the vertical direction. The through portion 21g opens upward. As shown in Figure 3, the motor shaft 52a is passed through the through portion 21g in the axial direction. The supported portion 51d of the motor housing 51 is located inside the through portion 21g. As shown in Figure 5, the inner surface of the through portion 21g has a bottom surface portion 21m and a pair of side portions 21n. The bottom surface portion 21m is the lower part of the inner surface of the through portion 21g. The bottom surface portion 21m is located below the supported portion 51d. The pair of side portions 21n are the portions located on both sides of the inner surface of the through portion 21g in the width direction (X-axis direction). The pair of side portions 21n are located on both sides of the supported portion 51d in the width direction. The bottom portion 21m contacts the lower end of the supported portion 51d. The pair of side portions 21n contact the ends of the supported portion 51d on both sides in the width direction, respectively. As a result, the supported portion 51d is supported in the vertical and width directions by the inner surface of the through portion 21g.

[0041] A retaining member 55 is positioned above the supported portion 51d. The retaining member 55 presses the motor 50 from above. The retaining member 55 is fixed to the case 10. The retaining member 55 sandwiches the supported portion 51d between itself and the bottom surface portion 21m in the vertical direction. Therefore, the retaining member 55 can prevent the supported portion 51d from moving upward. Thus, in this embodiment, the supported portion 51d is stably supported in the vertical direction by the retaining member 55 and the bottom surface portion 21m, and is also stably supported in the width direction (X-axis direction) by the pair of side portions 21n. This prevents the motor 50 from moving in the vertical and width directions within the motor housing portion 20a. Furthermore, by supporting the annular supported portion 51d through which the motor shaft 52a passes, the first central axis J1 of the motor 50 can be positioned with high axial accuracy.

[0042] In this embodiment, the pressing member 55 is made of resin. However, the pressing member 55 may be made of a material other than resin, such as metal. As shown in Figure 9, the pressing member 55 has a fixed portion 55a, a first pressing portion 55b, and a pair of second pressing portions 55c. The fixed portion 55a extends in the width direction (X-axis direction). The fixed portion 55a has a pair of fixing holes 55f that penetrate the fixed portion 55a in the vertical direction. As shown in Figure 5, a pair of fixing protrusions 25 that protrude upward from the upper end of the first support wall portion 21b are passed through the pair of fixing holes 55f in the vertical direction. The pair of fixing protrusions 25 sandwich the penetrating portion 21g in the width direction when viewed in the vertical direction. When the pair of fixing protrusions 25 are passed through the pair of fixing holes 55f, the peripheral edges of the fixing holes 55f on the lower surface of the fixed portion 55a contact the upper surface of the first support wall portion 21b. The upper end of each fixing projection 25 is located above each fixing hole 55f. The protruding portion 25a of each fixing projection 25 that is located above each fixing hole 55f is formed, for example, by heat scribing to become a roughly hemispherical shape as shown by the dashed line in Figure 5, and contacts the upper surface of the fixed portion 55a. As a result, the retaining member 55 is fixed to the upper end of the first support wall portion 21b. Therefore, the retaining member 55 is fixed to the case 10.

[0043] The first pressing portion 55b extends downward from the fixed portion 55a. The widthwise dimension (X-axis direction) of the first pressing portion 55b is approximately the same as the widthwise dimension of the through portion 21g. The first pressing portion 55b is inserted into the through portion 21g from above and fitted into the through portion 21g. The lower end of the first pressing portion 55b is provided with a recess 55e that is recessed upward. The pair of inclined surfaces 55g located on both sides in the widthwise direction of the inner surface of the recess 55e approach each other in the widthwise direction as they move upward. The pair of inclined surfaces 55g contact the outer circumferential surface of the upper portion of the supported portion 51d and sandwich the outer circumferential surface of the upper portion of the supported portion 51d in the widthwise direction. The pair of inclined surfaces 55g also contact the outer circumferential surface of the supported portion 51d from above. Therefore, the first pressing portion 55b can press down on the supported portion 51d in the width direction, and it can also press down on the supported portion 51d from above.

[0044] As shown in Figure 10, the pair of second pressing portions 55c protrude downward from the fixed portion 55a. In this embodiment, the pair of second pressing portions 55c protrude downward from both ends in the width direction of the fixed portion 55a. As shown in Figure 8, one of the second pressing portions 55c is located on one side (+X side) in the width direction of the first central axis J1. The other second pressing portion 55c is located on the other side (-X side) in the width direction of the first central axis J1. The lower surfaces of the pair of second pressing portions 55c are arc-shaped when viewed in the axial direction, following the outer circumferential surface of the cylindrical portion 51a of the motor housing 51. The lower surfaces of the pair of second pressing portions 55c contact the outer circumferential surface of the cylindrical portion 51a from above. As a result, the cylindrical portion 51a is pressed from above by the pair of second pressing portions 55c. The lower surfaces of the pair of second pressing portions 55c are positioned lower as they move away from the other second pressing portion 55c in the width direction (X-axis direction). As a result, the upper portion of the cylindrical portion 51a is sandwiched in the width direction by the lower surfaces of the pair of second pressing portions 55c. This allows the pair of second pressing portions 55c to press down on the cylindrical portion 51a in the width direction.

[0045] As shown in Figure 8, the first case portion 21 has a pair of protruding wall portions 21h that protrude upward from the first bottom wall portion 21a of the motor housing portion 20a. The pair of protruding wall portions 21h are spaced apart in the width direction (X-axis direction). One protruding wall portion 21h is connected to one side wall portion 21d. The other protruding wall portion 21h is connected to the other side wall portion 21d. The pair of protruding wall portions 21h are located below the cylindrical portion 51a. The upper edges of the pair of protruding wall portions 21h are located lower as they move away from each of the pair of side wall portions 21d in the width direction. This prevents the upper edges of the pair of protruding wall portions 21h from contacting the cylindrical portion 51a. As shown in Figure 2, the pair of protruding wall portions 21h protrude upward from the portion of the first bottom wall portion 21a on one axial side (+Y side). The pair of protruding wall portions 21h are located on the other axial side (-Y side) of the first support wall portion 21b. The pair of protruding wall portions 21h face the first support wall portion 21b with a gap between them. The plate-shaped portion 51b is inserted into the axial gap between the pair of protruding wall portions 21h and the first support wall portion 21b. This positions the plate-shaped portion 51b in the axial direction. The plate-shaped portion 51b is, for example, fitted into the gap between the pair of protruding wall portions 21h and the first support wall portion 21b in the axial direction.

[0046] The second case section 22 is located on one axial side (+Y side) of the first case section 21. The second case section 22 extends in the width direction (X-axis direction). The second case section 22 is box-shaped and opens on one axial side. The second case section 22 has a reduction mechanism housing section 20b that houses the reduction mechanism 60 inside. Although not shown in the figures, in this embodiment, three reduction mechanism housing sections 20b are provided side by side in the width direction. Each of the three reduction mechanism housing sections 20b houses one of the reduction mechanisms 60 of the three actuator sections 100a. Each reduction mechanism housing section 20b is arranged side by side on one axial side of each motor housing section 20a.

[0047] The reduction gear housing 20b opens on one axial side (+Y side). The opening on one axial side of the reduction gear housing 20b is closed by the second cover 40. The wall portion of the wall portion constituting the reduction gear housing 20b that is located on the other axial side (-Y side) is the first support wall portion 21b that constitutes the wall portion on one axial side of the motor housing 20a. As shown in Figure 6, the reduction gear housing 20b has a first gear housing portion 21j and a second gear housing portion 21k.

[0048] The first gear housing 21j houses the first gear section 61. The portion of the motor shaft 52a to which the first gear section 61 is fixed is located inside the first gear housing 21j. The first gear housing 21j extends in the vertical direction. The first gear housing 21j opens upward. The first gear housing 21j is located on one axial side (+Y side) of the through section 21g. The inside of the first gear housing 21j is connected to the inside of the through section 21g.

[0049] The second gear housing 21k houses the second gear section 62 inside. The second gear housing 21k is located on one side (+X side) in the width direction of the first gear housing 21j. The interior of the second gear housing 21k is connected to the interior of the first gear housing 21j. The second gear housing 21k has a substantially circular shape when viewed in the axial direction, centered on the second central axis J2.

[0050] As shown in Figure 2, the substrate housing 23 houses the substrate 56 inside. The substrate 56 is electrically connected to the motor 50. The surface of the substrate 56 is oriented in the vertical direction. As shown in Figure 8, the substrate 56 has a portion located above each motor 50. Multiple conductive parts 53a extending upward from each of the motors 50 in the three actuator units 100a are electrically connected to the substrate 56. The multiple conductive parts 53a are electrically connected to the coils of the stator 53. The multiple conductive parts 53a may be composed of conductors that make up the coils of the stator 53, or they may be composed of busbars connected to those conductors. Although not shown, the substrate 56 has an inverter circuit that supplies power to the coils of the stator 53. The motor 50 is driven by the power supplied from the inverter circuit to the coils of the stator 53 via the multiple conductive parts 53a.

[0051] As shown in Figure 1, the substrate housing section 23 is a roughly rectangular box shape that extends in the width direction (X-axis direction) and opens to the top. As shown in Figure 2, the substrate housing section 23 is located above the first case section 21 and the second case section 22. The upper opening of the substrate housing section 23 is closed by the first cover 30. The substrate housing section 23 has a second bottom wall section 23a and a peripheral wall section 23b. The second bottom wall section 23a is the lower wall section of the walls constituting the substrate housing section 23. In this embodiment, the second bottom wall section 23a constitutes the upper wall section of the walls constituting the reduction mechanism housing section 20b. The peripheral wall section 23b protrudes upward from the outer peripheral edge of the second bottom wall section 23a. The peripheral wall section 23b is roughly rectangular in shape. The upper opening of the peripheral wall section 23b is the upper opening of the substrate housing section 23.

[0052] The axial dimension of the substrate housing section 23 is greater than the sum of the axial dimensions of the motor housing section 20a and the reduction mechanism housing section 20b. The substrate housing section 23 has a portion located above each motor housing section 20a and a portion located to one side (+Y side) in the axial direction from each motor housing section 20a. As described above, in this embodiment, the movable member 72 protrudes from the inside of the case 10 to the outside of the case 10 in one side in the axial direction. In other words, the substrate housing section 23 has a portion located on the side where the movable member 72 protrudes from the motor housing section 20a in the axial direction. Therefore, the substrate housing section 23 can be made larger in the axial direction while suppressing an increase in the overall axial dimension of the electric actuator 100. This makes it possible to make the substrate 56 housed in the substrate housing section 23 larger in the axial direction with its surface facing up and down. Therefore, compared to the case where the substrate 56 is positioned with its surface facing axially, it is possible to suppress the radial enlargement of the electric actuator 100, and also to suppress the overall axial enlargement of the electric actuator 100.

[0053] The interior of the portion of the substrate housing 23 located above each motor housing 20a is connected to the interior of each motor housing 20a through the first opening 21i of each motor housing 20a. The portion of the substrate housing 23 located axially to one side (+Y side) of each motor housing 20a has a portion located above the reduction mechanism housing 20b and a portion located axially to one side of the reduction mechanism housing 20b. The interior of the substrate housing 23 and the interior of the reduction mechanism housing 20b are separated by a second bottom wall 23a.

[0054] The substrate housing section 23 has a substrate support section 23c that supports the substrate 56. The substrate support section 23c protrudes upward from the second bottom wall section 23a. The substrate support section 23c has a base section 23d and a heat-screw section 23e. In other words, the case 10 has a base section 23d and a heat-screw section 23e. The base section 23d protrudes upward from the second bottom wall section 23a. The base section 23d is, for example, cylindrical. The base section 23d contacts the lower surface of the substrate 56. The base section 23d supports the substrate 56 from below.

[0055] The heat-crimped portion 23e is connected to the upper side of the base portion 23d. The heat-crimped portion 23e is the part that fixes the substrate 56 by heat crimping. In Figure 2, the heat-crimped portion 23e before heat crimping is shown by a solid line, and the heat-crimped portion 23e after heat crimping is shown by a dashed line. Before heat crimping, the heat-crimped portion 23e is cylindrical with a smaller outer diameter than the base portion 23d. Before heat crimping, the heat-crimped portion 23e is passed axially through a hole provided in the substrate 56. The portion of the heat-crimped portion 23e that protrudes above the substrate 56 before heat crimping is heat-crimped and becomes approximately hemispherical as shown by the dashed line in Figure 2, and this heat-crimped portion contacts the upper surface of the substrate 56. As a result, the substrate 56 is fixed by the heat-crimped portion 23e. In this way, by using heat crimping to fix the substrate 56, the part that fixes the substrate 56 does not protrude upward as much as when bolts are used to fix the substrate 56. Therefore, the increase in size of the electric actuator 100 in the vertical direction can be further suppressed. In this embodiment, multiple substrate support parts 23c are provided.

[0056] The first cover 30 is fixed to the upper end of the substrate housing section 23. The first cover 30 closes the upper opening of the substrate housing section 23. The first cover 30 has a top plate portion 31 and a frame-shaped portion 32. The top plate portion 31 is plate-shaped with its surface facing vertically. The frame-shaped portion 32 protrudes downward from the outer peripheral edge of the lower surface of the top plate portion 31. The frame-shaped portion 32 is roughly rectangular in shape. The frame-shaped portion 32 is fitted into the upper opening of the peripheral wall portion 23b of the substrate housing section 23. The space between the outer peripheral surface of the frame-shaped portion 32 and the inner peripheral surface of the peripheral wall portion 23b is sealed by a second sealing member 84. The second sealing member 84 is, for example, an O-ring.

[0057] The second cover 40 is located on one axial side (+Y side) of the second case portion 22. The second cover 40 closes the opening on one axial side of each reduction mechanism housing portion 20b. As shown in Figure 1, the second cover 40 has a first cylindrical portion 41, a cover portion 42, and a mounting portion 45. In other words, the case 10 has a first cylindrical portion 41, a cover portion 42, and a mounting portion 45. The mounting portion 45 is the part for attaching the electric actuator 100 to the equipment on which the electric actuator 100 is mounted. The mounting portions 45 are provided on both sides in the width direction of the second cover 40.

[0058] The first cylindrical portion 41 is a cylindrical portion that extends in the axial direction. The first cylindrical portion 41 opens on both sides in the axial direction. In this embodiment, the first cylindrical portion 41 is substantially cylindrical with the second central axis J2 as its center. The first cylindrical portion 41 is provided for each actuator portion 100a. In this embodiment, three first cylindrical portions 41 are provided spaced apart in the width direction (X-axis direction).

[0059] As shown in Figure 2, the first cylindrical portion 41 is located on one axial side (+Y side) of the reduction mechanism 60. More specifically, the first cylindrical portion 41 is located on one axial side of the second gear portion 62. The other axial end (-Y side) of the first cylindrical portion 41 is located inside the reduction mechanism housing portion 20b. At least a portion of the rotating member 71 is located inside the first cylindrical portion 41. In this embodiment, almost the entire portion of the rotating member 71 that is located on one axial side of the portion to which the second gear portion 62 is fixed is located inside the first cylindrical portion 41. A portion of the movable member 72 is located inside the first cylindrical portion 41. The movable member 72 protrudes from an opening on one axial side of the first cylindrical portion 41 to the other axial side. When the movable member 72 is located furthest to the other axial side, the connected portion 72b is located outside the first cylindrical portion 41, and almost the entire second cylindrical portion 72a is located inside the first cylindrical portion 41. The first cylindrical portion 41 has a screw housing portion 41a and a seal housing portion 41b.

[0060] The screw housing portion 41a is a portion that houses at least a part of the first threaded portion 71c and at least a part of the second threaded portion 72c. In this embodiment, the screw housing portion 41a houses the entire first threaded portion 71c. However, a part of the first threaded portion 71c may be located outside the screw housing portion 41a. When the movable member 72 is in its furthest axial position on the other side (-Y side), the screw housing portion 41a houses the entire second threaded portion 72c. When the movable member 72 is in its furthest axial position on the one side (-Y side), the screw housing portion 41a houses the part of the second threaded portion 72c on the other axial side. However, regardless of the axial position of the movable member 72, the entire second threaded portion 72c may be housed inside the screw housing portion 41a, or a part of the second threaded portion 72c may be located outside the screw housing portion 41a.

[0061] The screw housing portion 41a is cylindrical in shape and extends in the axial direction. In this embodiment, the screw housing portion 41a is substantially cylindrical with respect to the second central axis J2. The screw housing portion 41a has a second opening 41c that opens on one side (+Y side) in the axial direction. The second opening 41c is the axial end of the screw housing portion 41a. The axial end of the screw housing portion 41a is the axial end of the first cylindrical portion 41. The movable member 72 is passed through the second opening 41c in the axial direction. The movable member 72 protrudes from the inside of the screw housing portion 41a to the outside of the screw housing portion 41a through the second opening 41c. The movable member 72 is fitted into the inside of the screw housing portion 41a. In this embodiment, the second opening 41c opens into an external space S1a located outside the electric actuator 100. The external space S1a is filled with fluid flowing through a channel that is switched by the electric actuator 100. Therefore, fluid flows into the first cylindrical portion 41 from the second opening 41c. This fluid is, for example, water. However, this fluid may be a fluid other than water, such as oil. In the external space S1a, the portion of the movable member 72 located axially to one side of the first cylindrical portion 41 is exposed.

[0062] As shown in Figure 7, the inner surface of the screw housing portion 41a has a support surface 44. In this embodiment, the support surface 44 is a surface that supports the movable member 72 so that it can move in the axial direction. The support surface 44 has a curved support portion 44a and a pair of flat support portions 44b. The curved support portion 44a is an arc-shaped surface centered on the second central axis J2 when viewed in the axial direction. The curved support portion 44a faces or contacts the arc-shaped surface of the outer circumferential surface of the movable member 72, which is centered on the second central axis J2 when viewed in the axial direction, with a small gap between them, and supports the arc-shaped surface. The shape of the support surface 44 is not particularly limited as long as the movable member 72 can be supported by the support surface 44. For example, the support surface 44 may be shaped to protrude inward from the first cylindrical portion 41 to the extent that it does not significantly hinder the axial movement of the movable member 72. In this case, the shape of the outer circumferential surface of the movable member 72 can be designed as appropriate.

[0063] The pair of planar support portions 44b are arranged to sandwich the second central axis J2 in the width direction (X-axis direction). The pair of planar support portions 44b each support a pair of planar portions 72d on the outer circumferential surface of the movable member 72. The pair of planar portions 72d face or contact each of the pair of planar support portions 44b with a small gap between them. Therefore, even if the movable member 72 attempts to rotate when the rotating member 71 rotates, the planar portions 72d hit the planar support portions 44b, preventing the movable member 72 from rotating. As a result, the second threaded portion 72c provided on the movable member 72 is fed axially, and the movable member 72 moves axially without rotating. The pair of planar support portions 44b are provided on one axial side (+Y side) of the inner surface of the threaded housing portion 41a. The other axial side (-Y side) end of the pair of planar support portions 44b is positioned further axially than the other axial side end of the threaded housing portion 41a. In this embodiment, the pair of planar support portions 44b are each divided vertically by grooves 43, which will be described later. The portion of the inner surface of the screw housing portion 41a other than the portion where the pair of planar support portions 44b are provided and the portion where the grooves 43 are provided is the curved support portion 44a.

[0064] A groove 43 extending in the axial direction is provided on the inner surface of the screw housing portion 41a. The groove 43 is recessed inward from the support surface 44 in the radial direction centered on the second central axis J2. As shown in Figure 2, the groove 43 extends from one axial end (+Y side) of the screw housing portion 41a to the other axial end (-Y side) of the screw housing portion 41a. The groove 43 opens on both axial sides. The other axial end of the groove 43 opens into the interior of the seal housing portion 41b.

[0065] As shown in Figure 7, in this embodiment, multiple grooves 43 are provided at intervals in the circumferential direction around the second central axis J2. The multiple grooves 43 are arranged at equal intervals over a full circumference in the circumferential direction around the second central axis J2. In this embodiment, four grooves 43 are provided. The four grooves 43 include a pair of grooves 43 that sandwich the second central axis J2 in the vertical direction, and a pair of grooves 43 that sandwich the second central axis J2 in the width direction (X-axis direction). The portions on one axial side (+Y side) of the pair of grooves 43 that sandwich the second central axis J2 in the width direction are provided on a pair of planar support parts 44b, and each of the pair of planar support parts 44b is divided in the vertical direction.

[0066] As shown in Figure 2, the seal housing 41b is located on the other axial side (-Y side) of the screw housing 41a. The axial end (+Y side) of the seal housing 41b is connected to the axial end of the screw housing 41a. The seal housing 41b is an annular shape with the second central axis J2 as its center. The axial end of the seal housing 41b is the axial end of the first cylindrical portion 41. The inner diameter of the seal housing 41b is larger than the inner diameter of the screw housing 41a. The rotating member 71 is passed through the interior of the seal housing 41b in the axial direction.

[0067] The seal housing portion 41b houses the first seal member 80 inside. In other words, the first seal member 80 is positioned inside the first cylindrical portion 41. The first seal member 80 seals the space between the inner surface of the first cylindrical portion 41 and the rotating member 71. In this embodiment, the first seal member 80 seals the space between the inner circumferential surface of the seal housing portion 41b and the outer circumferential surface of the shaft body portion 71a of the rotating member 71. The first seal member 80 is an annular shape centered on the second central axis J2. The first seal member 80 is, for example, a seal member having a lip portion that is pressed against the outer circumferential surface of the rotating member 71. The first seal member 80 is located on the other axial side (-Y side) of the movable member 72. Even if fluid enters the interior of the first cylindrical portion 41 from the second opening 41c, the first seal member 80 can prevent the fluid from reaching the reduction mechanism 60 and the motor 50.

[0068] A plate member 83 is positioned on the other axial side (-Y side) of the first sealing member 80. The plate member 83 supports the first sealing member 80 from the other axial side. Therefore, it is possible to prevent the first sealing member 80 from coming out of the first cylindrical portion 41. The plate surface of the plate member 83 faces axially. As shown in Figure 11, the plate member 83 has a rounded rectangular shape when viewed in the axial direction. The plate member 83 has a through hole 83a that penetrates the plate member 83 in the axial direction. As shown in Figure 2, the shaft body portion 71a of the rotating member 71 is passed through the through hole 83a in the axial direction. The outer peripheral edge of the surface on one axial side (+Y side) of the plate member 83 contacts the end face on the other axial side of the first cylindrical portion 41. As shown in Figure 11, the plate member 83 is supported in the vertical and widthwise directions (X-axis direction) by the frame portion 42b of the cover portion 42, which will be described later, and the projection 41d that protrudes from the other axial end face of the first cylindrical portion 41 toward the other axial direction.

[0069] As shown in Figure 2, the plate member 83 is located on one axial side (+Y side) of the reduction mechanism 60. More specifically, the plate member 83 is located on one axial side of the second gear section 62. The plate member 83 sandwiches the second gear section 62 between itself and the first support wall section 21b in the axial direction. In other words, at least a portion of the reduction mechanism 60 is located between the plate member 83 and the first support wall section 21b in the axial direction. In this embodiment, the second gear section 62, which is part of the reduction mechanism 60, is located between the plate member 83 and the first support wall section 21b in the axial direction.

[0070] A first spacer 81 surrounding the rotating member 71 is positioned between the plate member 83 and the reduction mechanism 60 in the axial direction. A second spacer 82 surrounding the rotating member 71 is positioned between the reduction mechanism 60 and the first support wall 21b in the axial direction. As a result, the gap between the plate member 83 supporting the first seal member 80 and the reduction mechanism 60, and the gap between the reduction mechanism 60 and the first support wall 21b, can be filled by the first spacer 81 and the second spacer 82, respectively. This prevents the plate member 83 from moving in the axial direction without fixing it with bolts or the like. Therefore, there is no need to provide bolts or the like to fix the plate member 83, and the number of parts and assembly man-hours of the electric actuator 100 can be reduced. Furthermore, by adjusting the axial dimensions of the first spacer 81 and the second spacer 82, axial play of the plate member 83 can be effectively suppressed.

[0071] The first spacer 81 is located between the plate member 83 and the second gear portion 62 in the axial direction. The first spacer 81 contacts at least one of the plate member 83 and the second gear portion 62. The second spacer 82 is located between the second gear portion 62 and the first support wall portion 21b in the axial direction. The second spacer 82 contacts at least one of the second gear portion 62 and the first support wall portion 21b. As shown in Figure 11, the first spacer 81 and the second spacer 82 are annular in shape surrounding the second central axis J2. The first spacer 81 and the second spacer 82 are plate-shaped with their plate surfaces facing axially. The first spacer 81 and the second spacer 82 are, for example, washers. The axial dimensions of the first spacer 81 and the axial dimensions of the second spacer 82 may be the same as or different from each other. Workers assembling the electric actuator 100 can appropriately select the spacers to be used as the first spacer 81 and the second spacer 82 according to the tolerances of each component being assembled.

[0072] The cover portion 42 connects a plurality of first cylindrical portions 41. The cover portion 42 has a cover body portion 42a and a frame portion 42b. The cover body portion 42a extends in the width direction (X-axis direction). In this embodiment, the cover body portion 42a is plate-shaped with its plate surface facing the axial direction. The cover body portion 42a connects a plurality of first cylindrical portions 41. More specifically, the cover body portion 42a connects the connection portions between the screw housing portion 41a and the seal housing portion 41b in each first cylindrical portion 41. As shown in Figure 3, the cover body portion 42a closes the opening on one axial side (+Y side) of the second case portion 22. The frame portion 42b protrudes from the outer peripheral edge of the cover body portion 42a to the other axial side (-Y side). The frame portion 42b is a substantially rectangular frame shape that is long in the width direction (X-axis direction). The frame portion 42b is fitted inside the second case portion 22. The space between the outer circumferential surface of the frame portion 42b and the inner circumferential surface of the second case portion 22 is sealed by the third sealing member 85. The third sealing member 85 is, for example, an O-ring.

[0073] As shown in Figure 2, the electric actuator 100 includes a path portion 90 which is provided in the case 10, at least in part. The path portion 90 has a portion formed by grooves 43. The path portion 90 connects the space S1b located on the other axial side (-Y side) of the movable member 72 when the movable member 72 moves in the axial direction, and the external space S1a located on one axial side (+Y side) of the screw housing portion 41a. Therefore, when the movable member 72 moves in the axial direction with fluid inside the first cylindrical portion 41, the fluid can flow between the space S1b and the external space S1a via the path portion 90. Since the path portion 90 has a portion formed by grooves 43, fluid flows easily within the path portion 90. As a result, even if the volume of the space S1b changes as the movable member 72 moves in the axial direction, it is easy to introduce fluid into the space S1b or to release fluid from the space S1b via the path portion 90. Therefore, differences in fluid pressure between space S1b and the external space S1a can be effectively suppressed, and the force required to move the movable member 72 in the axial direction can be effectively suppressed. As a result, the torque of the motor 50 required to move the movable member 72 in the axial direction can be reduced. This allows for miniaturization of the motor 50. Consequently, the electric actuator 100 can be miniaturized.

[0074] In this embodiment, as described above, a reduction mechanism 60 is provided connected to the rotor 52, and the rotation of the rotor 52 is transmitted to the rotating member 71 via the reduction mechanism 60. Therefore, the torque of the motor 50 is increased by the reduction mechanism 60 and transmitted to the rotating member 71. This makes it possible to reduce the torque of the motor 50 required to rotate the rotating member 71 and move the moving member 72 in the axial direction. Consequently, the motor 50 can be made smaller, and the electric actuator 100 can be made smaller.

[0075] In this embodiment, space S1b is the space located in the axial direction between the movable member 72 and the first sealing member 80. Space S1b also includes the space located on one axial side (+Y side) of the first sealing member 80 within the internal space of the seal housing 41b. The volume of space S1b increases when the movable member 72 moves in one axial direction. The volume of space S1b decreases when the movable member 72 moves in the other axial direction (-Y side).

[0076] In this embodiment, as described above, at least a portion of the rotating member 71 is located inside the second cylindrical portion 72a of the movable member 72. The second cylindrical portion 72a opens to the other axial side (-Y side). Therefore, the internal space of the second cylindrical portion 72a is connected to the space S1b located on the other axial side of the movable member 72. As a result, the internal space of the second cylindrical portion 72a is connected to the external space S1a via the space S1b and the path portion 90. Consequently, when the movable member 72 moves in the axial direction, fluid can be easily flowed between the internal space of the second cylindrical portion 72a and the external space S1a. Therefore, the torque of the motor 50 required to move the movable member 72 in the axial direction can be reduced. As a result, the motor 50 can be made smaller, and the electric actuator 100 can be made smaller. Furthermore, by having a structure in which the movable member 72 has a second cylindrical portion 72a with a second threaded portion 72c on its inner circumferential surface, the structure of the electric actuator 100 can be simplified compared to the case in which a cylindrical portion into which the movable member 72 is inserted is provided with the rotating member 71.

[0077] In this embodiment, the path portion 90 has an axially extending extension path portion 91. The extension path portion 91 is composed of a groove 43. Therefore, the axially extending extension path portion 91 easily connects the external space S1a and space S1b. In this embodiment, the extension path portion 91 is composed of a groove 43 provided on the inner surface of the first cylindrical portion 41 and opening on one side in the axial direction (+Y side). The inner surface of the extension path portion 91 is the inner surface of the groove 43. As shown in Figure 12, the inner surface of the extension path portion 91 is connected to the support surface 44. Therefore, the fluid flowing inside the extension path portion 91 enters the gap between the support surface 44 and the movable member 72, making it easier to move the movable member 72 in the axial direction.

[0078] As shown in Figure 2, the extension path portion 91 opens on both sides in the axial direction. The end of the extension path portion 91 on one axial side (+Y side) opens to the external space S1a and connects to the external space S1a. The portion of the extension path portion 91 located on the other axial side (-Y side) of the movable member 72 opens to space S1b and connects to space S1b. In this embodiment, when the movable member 72 is in its furthest axial position on the other side, the end of the extension path portion 91 on the other axial side connects to space S1b.

[0079] As shown in Figure 12, in this embodiment, four grooves 43 are provided, and therefore four extension path sections 91 are also provided. The four extension path sections 91 are arranged at equal intervals around the second central axis J2 in the circumferential direction. The four extension path sections 91 include a pair of extension path sections 91 that sandwich the second central axis J2 in the vertical direction, and a pair of extension path sections 91 that sandwich the second central axis J2 in the width direction (X-axis direction).

[0080] In this embodiment, the path portion 90 has a gap path portion 92. The gap path portion 92 is formed by the gap between the flat portion 72d of the movable member 72 and the curved support portion 44a on the inner surface of the first cylindrical portion 41. The gap path portion 92 is provided between the portion of the curved support portion 44a located on the other axial side (-Y side) of the flat support portion 44b and the flat portion 72d. A pair of gap path portions 92 are provided, sandwiching the second central axis J2 in the width direction (X-axis direction). The pair of gap path portions 92 are located radially inward around the second central axis J2 with respect to each of the pair of extension path portions 91 that are arranged sandwiching the second central axis J2 in the width direction, and are connected to each of the pair of extension path portions 91. In this embodiment, instead of providing the planar support portion 44b along the entire axial length of the inner surface of the first cylindrical portion 41, the planar support portion 44b is positioned further axially (towards the +Y side) than the other axial end of the first cylindrical portion 41, thereby creating a gap path portion 92. This makes it easier for fluid to flow through the path portion 90. Furthermore, since the area of ​​the outer surface of the movable member 72 that rubs against the inner surface of the first cylindrical portion 41 can be reduced, the movable member 72 can be moved more easily in the axial direction.

[0081] The following describes embodiments that differ from those described above. In the following descriptions of each embodiment, components similar to those described in the section above may be omitted from the description by using the same reference numerals as appropriate. Also, for parts corresponding to the components described in the section above each embodiment, the same name and different reference numerals will be used to explain the differences from the above-described configuration, while the explanation of similar components may be omitted. Note that, within the scope of consistency, components similar to those described in the section above each embodiment may be adopted as components whose description is omitted.

[0082] <Second Embodiment> As shown in Figure 13, the case 210 of the electric actuator 200 differs in the configuration of the second cover 240 from that of the first embodiment. In the first cylindrical portion 241 of the second cover 240, the screw housing portion 241a has a small diameter portion 241e and a large diameter portion 241f. The small diameter portion 241e is the portion having a support surface 44. The large diameter portion 241f is located on the other axial side (-Y side) of the small diameter portion 241e. The end of the large diameter portion 241f on one axial side (+Y side) is connected to the end of the small diameter portion 241e on the other axial side. The inner diameter of the large diameter portion 241f is larger than the inner diameter of the small diameter portion 241e. Therefore, the inner circumferential surface of the large diameter portion 241f is positioned away from the outer circumferential surface of the movable member 72 and does not come into contact with the outer circumferential surface of the movable member 72. This allows a gap path portion 293 with a larger flow path cross-sectional area than the extended path portion 291 to be provided between the inner circumferential surface of the large-diameter portion 241f and the outer circumferential surface of the movable member 72. Therefore, fluid can flow more easily into the path portion 290. In addition, the provision of the large-diameter portion 241f allows the axial dimension of the small-diameter portion 241e on which the support surface 44 is provided to be reduced. This reduces the area of ​​the outer circumferential surface of the movable member 72 that rubs against the inner surface of the first cylindrical portion 241 when the movable member 72 moves in the axial direction. Therefore, the movable member 72 can be moved more easily in the axial direction.

[0083] In this embodiment, the extension path portion 291 is composed of a groove 243 extending from one axial end to the other axial end of the small-diameter portion 241e. The other axial end of the extension path portion 291, i.e., the other axial end of the groove 243, connects to the interior of the large-diameter portion 241f. The extension path portion 291 connects to space S1b via the gap path portion 293. The other configurations of the electric actuator 200 are the same as those of the electric actuator 100 in the first embodiment.

[0084] <Third Embodiment> As shown in Figure 14, the configuration of the actuator portion 300a of the electric actuator 300 of this embodiment differs from that of the electric actuator 100 of the first embodiment. In the actuator portion 300a, the rotating member 371 has a third cylindrical portion 371a, a shaft portion 371d, and a supported shaft portion 71b. The third cylindrical portion 371a is cylindrical and extends in the axial direction. More specifically, the third cylindrical portion 371a is substantially cylindrical with respect to the second central axis J2. The third cylindrical portion 371a opens on one side in the axial direction (+Y side). The other end of the third cylindrical portion 371a in the axial direction is closed. The third cylindrical portion 371a has a first threaded portion 371c on its inner circumferential surface. The third cylindrical portion 371a is located inside the first cylindrical portion 341 in the second cover 240. The outer circumferential surface of the third cylindrical portion 371a is rotatably supported around the second central axis J2 by ​​a support surface 344 provided on the inner surface of the first cylindrical portion 341. In other words, in this embodiment, the support surface 344 supports the rotating member 371. In this embodiment, unlike the support surface 44 of the first embodiment, the support surface 344 does not have a planar support portion 44b. The other configurations of the first cylindrical portion 341 are the same as the other configurations of the first cylindrical portion 41 in the first embodiment.

[0085] The third cylindrical portion 371a has a hole 371e that penetrates the third cylindrical portion 371a from its inner circumferential surface to its outer circumferential surface. In this embodiment, the hole 371e is provided at the other axial end (-Y side) of the circumferential wall portion of the third cylindrical portion 371a. Multiple holes 371e are provided at intervals in the circumferential direction around the second central axis J2. The shaft portion 371d extends from the other axial end of the third cylindrical portion 371a to the other axial side. The shaft portion 371d is passed through the seal housing portion 41b in the axial direction. The second gear portion 62 is fixed to the shaft portion 371d. The supported shaft portion 71b is connected to the other axial end of the shaft portion 371d.

[0086] The movable member 372 of the actuator section 300a is a shaft extending in the axial direction. The movable member 372 has a main shaft section 372a and a connected section 72b. The main shaft section 372a extends in the axial direction. A second threaded section 372c is provided on the outer circumferential surface of the main shaft section 372a. In other words, the movable member 372 has a second threaded section 372c on its outer circumferential surface. At least a portion of the main shaft section 372a is located inside the third cylindrical section 371a. In other words, at least a portion of the movable member 372 is located inside the third cylindrical section 371a. The outer diameter of the main shaft section 372a is smaller than the outer diameter of the connected section 72b. The movable member 372 is prevented from rotating around the second central axis J2 by, for example, connecting a drive object (not shown) to the connected section 72b.

[0087] Furthermore, a projection 372h is provided on a part of the support surface 344 near the second opening (opening) 41c, projecting radially inward with respect to the second central axis J2. A flat portion 372g extending in the axial direction is provided on the outer diameter portion of the movable member 372 having the second threaded portion 372c, i.e., the outer diameter portion of the main shaft portion 372a. The tip of the projection 372h contacts the flat portion 372g, thereby preventing the movable member 372 from rotating around the second central axis J2. The flat portion 372g may be the bottom surface of a groove extending in the axial direction, or it may have a shape similar to the flat portion 72d provided on the outer circumferential surface of the movable member 72 in the first embodiment.

[0088] In this embodiment, the path portion 390 has both a portion composed of grooves and a portion composed of holes. The path portion 390 has an extended path portion 91 and a holed path portion 392. The holed path portion 392 is a portion composed of a hole 371e that penetrates the third cylindrical portion 371a from the inner circumferential surface to the outer circumferential surface. Therefore, the space S2b provided inside the third cylindrical portion 371a and the external space S1a can be connected by the path portion 390. As a result, when the movable member 372, at least a part of which is located inside the third cylindrical portion 371a, moves in the axial direction, fluid can be suitably flowed between the space S2b located on the other axial side (-Y side) of the movable member 372 and the external space S1a via the path portion 390. Therefore, the torque of the motor 50 required to move the movable member 372 in the axial direction can be reduced, and the electric actuator 300 can be miniaturized. Space S2b is the internal space of the third cylindrical portion 371a located on the other side of the axial direction of the movable member 372. The hole path portion 392 connects space S2b and the extension path portion 91.

[0089] The other configurations of the actuator unit 300a are the same as those of the actuator unit 100a in the first embodiment. The other configurations of the electric actuator 300 are the same as those of the electric actuator 100 in the first embodiment.

[0090] The present invention is not limited to the embodiments described above, and other configurations and methods may be adopted within the scope of the technical idea of ​​the present invention. The path portion may have any portion as long as it has at least one of a portion made up of grooves and a portion made up of holes. The path portion may have a portion made up of holes without having a portion made up of grooves. If the path portion has an extended path portion that extends in a predetermined direction (axial direction), the extended path portion may be made up of holes. In this case, the extended path portion is made up of holes extending in a predetermined direction provided in the wall portion that constitutes the first cylindrical portion. The path portion may not be provided.

[0091] The bearing portion that rotatably supports the rotating member may have any configuration as long as it is provided on the support wall. The bearing portion may be formed by embedding a bearing, such as a rolling bearing, in the support wall. The entire rotating member may overlap with the motor when viewed in the axial direction. The first direction may be any direction other than that perpendicular to the axial direction, as long as it intersects with the axial direction.

[0092] The reduction gear mechanism may have any configuration as long as it can reduce the rotation of the rotor and transmit it to the rotating member. The reduction gear mechanism may consist of three or more gear sections. The reduction gear mechanism may have a structure that transmits rotation by pulleys and belts. The motor may be of any type. The motor may be an outer rotor type motor.

[0093] The applications of the electric actuator to which the present invention is applied are not particularly limited. The electric actuator may be mounted on any equipment.

[0094] Furthermore, this technology can be configured as follows: (1) An electric actuator comprising: a motor having a rotor that rotates about a first central axis; a reduction mechanism connected to the rotor; a rotating member that rotates about a second central axis extending in the axial direction of the first central axis, to which the rotation of the rotor is transmitted via the reduction mechanism; a movable member that moves in the axial direction in conjunction with the rotation of the rotating member; and a case having a motor housing portion that houses the motor inside, wherein the second central axis is positioned at a different location from the first central axis in the radial direction centered on the first central axis; the rotating member extends in the axial direction; the reduction mechanism is located on one side of the axial direction of the motor; the case has a support wall portion that supports the motor from one side of the axial direction between the motor and the reduction mechanism; the support wall portion has a bearing portion that rotatably supports the other end of the rotating member in the axial direction; and at least a part of the rotating member overlaps with the motor when viewed in the axial direction. (2) The motor housing has an opening that opens to one side in a first direction intersecting the axial direction, and the opening is sized to allow the motor to pass in the first direction, as in (1). (3) The electric actuator according to (2), comprising a pressing member for pressing the motor from one side in the first direction, the motor having a motor housing, the rotor having a motor shaft protruding from the inside of the motor housing to the outside of the motor housing in one axial direction, the support wall having a through portion that penetrates the support wall in the axial direction, the through portion opening to one side in the first direction, the motor shaft passing through the through portion in the axial direction and connected to the reduction mechanism, the motor housing having a supported portion supported by the inner surface of the through portion, the inner surface of the through portion having a bottom portion located on the other side of the supported portion in the first direction, and a pair of side portions located on both sides of the supported portion in a second direction perpendicular to both the axial direction and the first direction, and the pressing member being fixed to the case and sandwiching the supported portion between the bottom portion and the first direction. (4) The electric actuator according to (2) or (3), comprising a circuit board electrically connected to the motor, wherein the case has a circuit board housing portion for housing the circuit board, the circuit board housing portion having a portion located on one side of the motor housing portion in the first direction and a portion located on one side in the axial direction from the motor housing portion, and the moving member protruding from the inside of the case to the outside of the case on one side in the axial direction. (5) The electric actuator according to (4), wherein the case has a heat crimping portion for fixing the substrate. (6) The electric actuator according to any one of (1) to (5), further comprising an elastic member located inside the motor housing on the other side of the axial direction of the motor, wherein the elastic member sandwiches the motor between the support wall and the motor in the axial direction and contacts the motor in an elastically deformed state. (7) The electric actuator according to any one of (1) to (6), wherein the case has a cylindrical portion extending in the axial direction, the cylindrical portion is open on both sides in the axial direction, at least a portion of the rotating member is located inside the cylindrical portion, and a sealing member is disposed inside the cylindrical portion to seal the space between the inner surface of the cylindrical portion and the rotating member. (8) The electric actuator according to (7), further comprising a plate member that supports the sealing member from the other axial side, wherein at least a portion of the reduction mechanism is located between the plate member and the support wall in the axial direction, a first spacer surrounding the rotating member is disposed between the plate member and the reduction mechanism in the axial direction, and a second spacer surrounding the rotating member is disposed between the reduction mechanism and the support wall in the axial direction. (9) The electric actuator according to any one of (1) to (8), wherein the reduction mechanism comprises a first gear portion that rotates together with the rotor about a first central axis, and a second gear portion that meshes with the first gear portion and rotates together with the rotating member about a second central axis.

[0095] The configurations and methods described herein can be combined as appropriate, within the bounds of non-inconsistency. [Explanation of symbols]

[0096] 10,210…Case, 20a…Motor housing, 21b…First support wall (support wall), 21e…Bearing section, 21g…Through section, 21i…First opening (opening), 21m…Bottom section, 21n…Side section, 23…Substrate housing, 23e…Heat crimping section, 41,241,341…First cylindrical section (cylindrical section), 50…Motor, 51…Motor housing, 51d…Supported section, 52…Rotor, 52a… Motor shaft, 54...Elastic member, 55...Pressing member, 56...Base plate, 60...Reduction mechanism, 61...First gear section, 62...Second gear section, 71, 371...Rotating members, 72, 372...Moving members, 80...First sealing member (sealing member), 81...First spacer, 82...Second spacer, 83...Plate member, 100, 200, 300...Electric actuator, J1...First central axis, J2...Second central axis

Claims

1. A motor having a rotor that rotates around a first central axis, A reduction mechanism connected to the rotor, The rotation of the rotor is transmitted via the reduction mechanism, and a rotating member rotates around a second central axis extending in the axial direction of the first central axis, A movable member that moves in the axial direction as the rotating member rotates, A case having a motor housing section that houses the motor inside, Equipped with, The second central axis is positioned at a different location from the first central axis in the radial direction centered on the first central axis. The rotating member extends in the axial direction, The reduction mechanism is located on one axial side of the motor, The case has a support wall portion that supports the motor from one axial side between the motor and the reduction mechanism in the axial direction, The support wall portion has a bearing portion that rotatably supports the other end of the rotating member on the axial side, At least a portion of the rotating member is an electric actuator that overlaps with the motor when viewed in the axial direction.

2. The motor housing has an opening that opens on one side in a first direction intersecting the axial direction, The electric actuator according to claim 1, wherein the opening is sized to allow the motor to pass in the first direction.

3. The motor is provided with a pressing member that presses it from one side in the first direction, The motor has a motor housing, The rotor has a motor shaft that protrudes from the inside of the motor housing to the outside of the motor housing in one axial direction. The support wall portion has a through portion that penetrates the support wall portion in the axial direction, The aforementioned through portion opens to one side in the first direction, The motor shaft is passed through the through-port in the axial direction and connected to the reduction mechanism. The motor housing has a supported portion that is supported by the inner surface of the through portion, The inner surface of the aforementioned through portion is The bottom surface portion located on the other side of the supported portion in the first direction, A pair of side surfaces located on both sides of the supported portion in a second direction perpendicular to both the axial direction and the first direction, It has, The electric actuator according to claim 2, wherein the pressing member is fixed to the case and sandwiches the supported portion between the bottom surface and the pressing member in the first direction.

4. The motor is electrically connected to a circuit board, The case has a substrate housing section that houses the substrate inside, The aforementioned substrate housing section is The portion located on one side of the motor housing in the first direction, A portion located on one axial side of the motor housing, It has, The electric actuator according to claim 2, wherein the moving member protrudes from the inside of the case to the outside of the case in one axial direction.

5. The electric actuator according to claim 4, wherein the case has a heat-sealed portion for fixing the substrate.

6. The motor housing includes an elastic member located on the other side of the axial direction of the motor, The electric actuator according to claim 1, wherein the elastic member sandwiches the motor between the support wall and the motor in an axial position and contacts the motor in an elastically deformed state.

7. The case has a cylindrical portion extending in the axial direction, The cylindrical portion has openings on both sides in the axial direction, At least a portion of the rotating member is located inside the cylindrical portion, An electric actuator according to any one of claims 1 to 6, wherein a sealing member is disposed inside the cylindrical portion to seal the space between the inner surface of the cylindrical portion and the rotating member.

8. The sealing member is supported from the other side in the axial direction by a plate member, At least a portion of the reduction mechanism is located between the plate member and the support wall in the axial direction, A first spacer surrounding the rotating member is positioned between the plate member and the reduction mechanism in the axial direction. The electric actuator according to claim 7, wherein a second spacer surrounding the rotating member is disposed between the reduction mechanism and the support wall in the axial direction.

9. The aforementioned reduction mechanism is A first gear section that rotates together with the rotor around the first central axis, A second gear portion meshes with the first gear portion and rotates together with the rotating member around the second central axis, An electric actuator according to any one of claims 1 to 6, having the following features.

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