Electric actuator

Abstract

An electric actuator according to one embodiment of the present invention is provided with: an output shaft; a motor; a decelerator; a rotation sensor that detects a rotation angle of the output shaft; a current sensor that detects a value of current flowing through the motor; and a control unit that controls the motor. The outer peripheral edge has first and second valleys having a bottom portion and two inclined surfaces connected to both sides of the bottom portion. The control unit performs: a first valley portion acquisition step of rotating the output shaft, acquiring a detection angle of the rotation sensor when a current value detected by the current sensor exceeds a threshold value when a contact position located at the first valley portion passes through the inclined surface, and acquiring a second valley portion on the basis of the acquired detection angle; acquiring a first bottom position rotation angle in a state in which the contact position is located at the bottom of the first valley; and a second valley acquisition step for estimating, on the basis of the angle information acquired in the first valley acquisition step, a second bottom position rotation angle in a state where the contact position is located at the bottom of the second valley.

Description

Technical Field

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

[0002] An electric actuator that drives a switching mechanism, such as a parking lock mechanism, based on vehicle operation is known (e.g., Patent Document 1). The switching mechanism driven by the electric actuator includes a stopper plate having a valley portion on its outer periphery, and a positioning mechanism in which a stopper roller of a leaf spring member engages with the valley portion of the stopper plate to maintain the rotational angle of the stopper plate. The switching mechanism maintains the rotational angle of the stopper plate by positioning the stopper roller at the bottom of the valley portion of the stopper plate. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-204043 Summary of the Invention

[0004] In a switching mechanism driven by an electric actuator, a self-learning method is used. This method detects the motor drive current in the electric actuator as the stop roller reciprocates in the valley of the stop plate. This method then determines the bottom angle (bottom position rotation angle) based on the rotation angle (learning point) at which the motor drive current exceeds a threshold. Conventionally, if the stop plate has multiple valleys, self-learning is performed separately for each valley, which increases the time required for self-learning.

[0005] In view of the above circumstances, one object of the present invention is to provide an electric actuator capable of efficiently acquiring the bottom position rotation angles of a plurality of valley portions included in a stopper plate (first member).

[0006] One embodiment of an electric actuator according to the present invention rotates a first plate-shaped member having a surface and an outer peripheral edge about a central axis perpendicular to the surface, thereby changing the contact position of a second member having a contact portion with the outer peripheral edge. The electric actuator includes: an output shaft extending about the central axis and connected to the first member; a motor; a speed reducer that reduces the rotation of the motor and rotates the output shaft about the central axis; a rotation sensor that detects the rotation angle of the output shaft; a current sensor that detects the current flowing through the motor; and a control unit that controls the motor. The outer peripheral edge includes a first valley and a second valley, each having a bottom and two inclined surfaces connected to either side of the bottom. The control unit performs: a first valley acquisition process, rotating the output shaft, acquiring a detection angle of the rotation sensor when the current value detected by the current sensor exceeds a threshold value when the contact position located at the first valley passes through the inclined surface, and acquiring a first bottom position rotation angle in a state where the contact position is located at the bottom of the first valley based on the acquired detection angle; and a second valley acquisition process, inferring a second bottom position rotation angle in a state where the contact position is located at the bottom of the second valley based on the angle information acquired in the first valley acquisition process.

[0007] According to the above aspect of the present invention, it is possible to provide an electric actuator capable of efficiently acquiring the bottom position rotation angles of a plurality of valley portions included in a stopper plate (first member). BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a diagram showing a drive device including an electric actuator according to an embodiment, as viewed from one side in the left-right direction of a vehicle. Figure 2 It is a perspective view showing a parking mechanism according to one embodiment. Figure 3 This is a cross-sectional view of an electric actuator according to one embodiment. Figure 4 This is a front view of a speed reducer according to one embodiment. Figure 5 This is a schematic diagram of a stopper plate and a contact portion according to one embodiment, illustrating an example of an initial state in a first valley portion acquisition step of a learning step. Figure 6 This is a schematic diagram of a stopper plate and a contact portion according to one embodiment, illustrating a first acquisition step in a first valley acquisition step of a learning process. Figure 7 This is a graph showing the relationship between the motor current value and the movement angle in the first acquisition step according to one embodiment. Figure 8This is a schematic diagram of a stopper plate and a contact portion according to one embodiment, illustrating a second acquisition step in the first valley acquisition step of a learning process. Figure 9 This is a graph showing the relationship between the motor current value and the movement angle in the second acquisition step according to one embodiment. Figure 10 This is a graph that combines graphs showing the relationship between the motor current value and the movement angle in the first acquisition step and the second acquisition step in one embodiment into one graph. Figure 11 This is a schematic diagram of a stopper plate and a contact portion according to one embodiment, illustrating an example of an initial state in the second valley portion acquisition step of the learning step. DETAILED DESCRIPTION

[0009] Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0010] Figure 1 This is a diagram of a drive device 1 including an electric actuator 10 according to the present embodiment, as viewed from one side in the left-right direction of a vehicle.

[0011] A drive device 1 according to the present embodiment is mounted on an electric vehicle such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHV), or an electric vehicle (EV), and is used as a drive source thereof.

[0012] In the following description, the vertical direction is defined based on the positional relationship when the drive device 1 is installed in a vehicle located on a horizontal road surface.

[0013] In the accompanying drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the Z-axis direction is a vertical direction with the +Z side as the upper side and the -Z side as the lower side. The X-axis direction is a direction perpendicular to the Z-axis direction and is the front-to-back direction of the vehicle on which the drive device 1 is installed. In addition, the +X side is one side of the front-to-back direction of the vehicle, and the -X side is the other side of the front-to-back direction of the vehicle. The Y-axis direction is a direction perpendicular to the X-axis direction and the Z-axis direction and is the left-to-right direction of the vehicle. In this embodiment, the +Y side is one side of the left-to-right direction of the vehicle, and the -Y side is the other side of the left-to-right direction of the vehicle.

[0014] In this embodiment, the direction parallel to the Z-axis direction is referred to as the "vertical direction Z", the direction parallel to the X-axis direction is referred to as the "front-back direction X", and the direction parallel to the Y-axis direction is referred to as the "left-right direction Y". In addition, the positive side (+Z side) of the Z-axis direction is referred to as the "upper side", and the negative side (-Z side) of the Z-axis direction is referred to as the "lower side". The positive side (+X side) of the X-axis direction is referred to as the "one side in the front-back direction", and the negative side (-X side) of the X-axis direction is referred to as the "other side in the front-back direction". The positive side (+Y side) of the Y-axis direction is referred to as the "one side in the left-right direction", and the negative side (-Y side) of the Y-axis direction is referred to as the "other side in the left-right direction".

[0015] like Figure 1 As shown, the drive device 1 includes a parking mechanism 100 , a housing 2 , a drive motor 3 , a reduction gear 4 , a differential device 5 , and a parking lock gear 6 .

[0016] The parking mechanism 100 includes a switching mechanism 70 and an electric actuator 10 .

[0017] The switching mechanism 70 includes a connecting shaft 80 connected to the electric actuator 10. The connecting shaft 80 extends in the front-rear direction X around the central axis J1.

[0018] The electric actuator 10 rotates the connecting shaft 80 around the central axis J1 .

[0019] In the following description, a radial direction centered on the central axis J1 may be simply referred to as the “radial direction,” and a circumferential direction centered on the central axis J1 , that is, a direction around the central axis J1 may be simply referred to as the “circumferential direction.”

[0020] The housing 2 accommodates the drive motor 3, the reduction gear 4, the differential gear 5, and the switching mechanism 70. Although not shown in the drawings, oil is accommodated in the housing 2.

[0021] The driving motor 3 is connected to a reduction device 4 .

[0022] The reduction device 4 is connected to the differential device 5 .

[0023] The differential device 5 transmits the torque output from the driving motor 3 to the axles of the vehicle via the reduction device 4 .

[0024] The parking lock gear 6 is fixed to a gear provided on the reduction gear 4. The parking lock gear 6 is connected to an axle of the vehicle via the reduction gear 4 and the differential 5. The parking lock gear 6 has a plurality of teeth 6a.

[0025] The switching mechanism 70 is driven by the electric actuator 10 based on a shift operation of the vehicle. The switching mechanism 70 switches the parking lock gear 6 between a locked state and an unlocked state.

[0026] The switching mechanism 70 locks the parking lock gear 6 when the shift position of the vehicle is the parking position (P range).

[0027] The switching mechanism 70 unlocks the parking lock gear 6 when the vehicle's shift position is a non-parking position other than the parking position. The non-parking position of the vehicle includes, for example, the drive position (D), the neutral position (N), or the reverse position (R).

[0028] Figure 2 It is a perspective view showing the parking mechanism 100 according to the present embodiment.

[0029] The switching mechanism 70 includes a connecting shaft 80 , a movable portion 70 a , a parking lock arm 77 , a base member 75 , and a leaf spring member (second member) 76 .

[0030] The connecting shaft 80 connects the electric actuator 10 and the movable portion 70 a and transmits the power of the electric actuator 10 to the movable portion 70 a. An end 81 of the connecting shaft 80 on one front-back side (+X side) is connected to the electric actuator 10 .

[0031] The end portion 81 is provided with a plurality of spline grooves extending in the front-rear direction X along the circumferential direction. Furthermore, the connecting shaft 80 is connected to the stopper plate (first component) 71 of the movable portion 70a. The connecting shaft 80 is integrally rotated about the central axis J1 by the power of the electric actuator 10, integrated with the stopper plate 71.

[0032] The movable portion 70 a moves in the left-right direction Y based on the shift operation of the vehicle. That is, in the present embodiment, the left-right direction Y corresponds to the moving direction of the movable portion 70 a .

[0033] In addition, the vertical direction Z corresponds to an intersecting direction intersecting with the moving direction of the movable portion 70 a , and the lower side corresponds to one side of the intersecting direction.

[0034] In this embodiment, the electric actuator 10 moves the movable portion 70a via the connecting shaft 80. The position of the movable portion 70a in the left-right direction Y is switched between at least the non-parking position and the parking position. In other words, the electric actuator 10 moves the movable portion 70a between the parking position and the non-parking position.

[0035] The non-parking position is the position of the movable portion 70a in the left-right direction Y when the shift position of the vehicle is other than the parking position.

[0036] The parking position is the position of the movable portion 70a in the left-right direction Y when the shift position of the vehicle is the parking position. The parking position is a position further to one side (+Y side) in the left-right direction than the non-parking position. Figure 2 The movable portion 70a is shown in the out-of-park position.

[0037] The movable portion 70 a includes a stopper plate 71 , a rod 72 , a conical member 73 , and a coil spring 74 .

[0038] The stopper plate 71 is fixed to the connecting shaft 80. The connecting shaft 80 rotates the stopper plate 71 around the central axis J1.

[0039] The stopper plate 71 extends radially outward from the connecting shaft 80. In the present embodiment, the stopper plate 71 extends upward from the connecting shaft 80.

[0040] In this embodiment, the stopper plate 71 is plate-shaped with its plate surface facing the front-rear direction X. The stopper plate 71 is substantially fan-shaped and has a surface 71 f perpendicular to the central axis J1 and an outer peripheral edge 71 a as a radially outer edge.

[0041] The outer peripheral edge 71 a is provided with a first valley portion 79A and a second valley portion 79B.

[0042] The first valley portion 79A is provided on one circumferential side of the stopper plate 71. That is, the first valley portion 79A is provided on one side (one outer peripheral edge) of the outer peripheral edge 71a of the stopper plate 71. The first valley portion 79A corresponds to the parking position.

[0043] The second valley portion 79B is provided on the other circumferential side of the stopper plate 71. That is, the second valley portion 79B is provided on the other side (the other outer peripheral edge) of the outer peripheral edge 71a of the stopper plate 71. The second valley portion 79B corresponds to the non-parking position.

[0044] The first and second valleys 79A, 79B are recessed radially inward of the central axis J1 at the outer peripheral edge of the stopper plate 71. The first and second valleys 79A, 79B penetrate the stopper plate 71 in the front-rear direction X.

[0045] The first valley portion 79A and the second valley portion 79B are arranged side by side in the circumferential direction of the central axis J1. The first valley portion 79A is located on the other side (-Y side) of the second valley portion 79B in the left-right direction.

[0046] By providing the first valley portion 79A and the second valley portion 79B in the stopper plate 71 , a ridge portion 71 c protruding radially outward is provided in a portion of the stopper plate 71 between the first valley portion 79A and the second valley portion 79B in the circumferential direction.

[0047] In the following description, the first valley portion 79A and the second valley portion 79B are simply referred to as valley portions 79 unless they are distinguished from each other. In this embodiment, the stopper plate 71 is described as having only the second valley portion 79B as the valley portion 79 corresponding to the non-parking position. However, the stopper plate 71 may also have multiple valley portions 79 corresponding to the non-parking position. In other words, three or more valley portions 79 may be provided on the outer peripheral edge 71a of the stopper plate 71.

[0048] The rod 72 is arranged to be movable in the left-right direction Y. The rod 72 includes a connecting portion 72 a and a rod body 72 b .

[0049] The connecting portion 72a is rod-shaped and extends in the front-back direction X. The end portion of the connecting portion 72a on one front-back direction (+X side) passes through the stopper plate 71 in the front-back direction X and is fixed to the stopper plate 71. Thus, the rod 72 is connected to the connecting shaft 80 via the stopper plate 71.

[0050] The rod body 72b is rod-shaped and extends in the left-right direction Y. In this embodiment, the rod body 72b extends from the other end (-X side) of the connecting portion 72a in the front-back direction to one side (+Y side) in the left-right direction.

[0051] The rod body 72b has a protrusion 72c at a portion close to the connection portion 72a. A cylindrical member 72d extending in the left-right direction Y is fitted and fixed to one end portion of the rod body 72b in the left-right direction.

[0052] The conical member 73 has a conical shape through which the rod body 72b passes. The conical member 73 extends in the left-right direction Y. The outer circumference of the conical member 73 on one side (+Y side) in the left-right direction is a tapered surface 73a, the outer diameter of which decreases toward the left-right side. The conical member 73 is movable in the left-right direction Y relative to the rod body 72b.

[0053] The coil spring 74 extends in the left-right direction Y. The coil spring 74 is arranged between the conical member 73 and the protrusion 72 c in the left-right direction Y. The rod body 72 b passes through the coil spring 74 .

[0054] The end of the coil spring 74 on the other left-right side (-Y side) contacts the protrusion 72c. The end of the coil spring 74 on one left-right side (+Y side) contacts the other left-right side of the conical member 73. The coil spring 74 expands and contracts as the conical member 73 moves relative to the rod body 72b in the left-right direction Y, applying an elastic force in the left-right direction Y to the conical member 73.

[0055] The parking lock arm 77 is located on the other side (-X side) of the movable portion 70a in the front-to-rear direction. The parking lock arm 77 is rotatably supported by a support shaft 78 centered about a rotation axis J3 extending in the left-right direction Y. The parking lock arm 77 includes a parking lock arm body 77a and an engaging portion 77b.

[0056] The parking lock arm body 77a extends toward one front-rear direction side (+X side) from the support shaft 78. An end portion 77c of the parking lock arm body 77a on one front-rear direction side contacts the movable portion 70a from above.

[0057] The meshing portion 77b protrudes upward from the parking lock arm body 77a. A coil spring (not shown) is mounted on the support shaft 78. The coil spring (not shown) applies a clockwise spring force to the parking lock arm 77 when viewed from the other side (-Y side) in the left-right direction, centered on the rotation axis J3.

[0058] Parking lock arm 77 moves as movable portion 70a moves. More specifically, parking lock arm 77 rotates about rotation axis J3 as rod 72 and conical member 73 move in left-right direction Y.

[0059] When the stopper plate 71 rotates from the non-parking position to the parking position in accordance with the rotation of the connecting shaft 80 , the rod 72 and the conical member 73 move to one side in the left-right direction (+Y side).

[0060] The outer diameter of the tapered surface 73a of the conical member 73 increases as it moves from one side (+Y side) toward the other side (-Y side). Therefore, when the conical member 73 moves toward one side, the end 77c of the parking lock arm 77 is lifted upward by the tapered surface 73a, causing the parking lock arm 77 to rotate counterclockwise about the rotation axis J3 as viewed from the other side (-Y side). As a result, the meshing portion 77b approaches the parking lock gear 6 and meshes between the teeth 6a of the parking lock gear 6.

[0061] When the parking lock gear 6 is meshed with the parking lock arm 77 , the conical member 73 is also located in the parking position, and the entire movable portion 70 a is located in the parking position.

[0062] That is, when the movable portion 70 a is located at the parking position, the parking lock arm 77 meshes with the parking lock gear 6 connected to the axle.

[0063] In the parking position, the conical member 73 is held in contact with a support portion 75b (described later) of the base member 75 and a parking lock arm 77. The parking lock arm 77 meshes with the parking lock gear 6, thereby locking the parking lock gear 6.

[0064] When parking lock arm 77 approaches parking lock gear 6, meshing portion 77b may come into contact with teeth 6a depending on the position of teeth 6a of parking lock gear 6. In this case, parking lock arm 77 may not be able to move to a position where meshing portion 77b meshes between teeth 6a.

[0065] Even in this case, in this embodiment, since the conical member 73 is movable in the left-right direction Y relative to the rod 72, the rod 72 can move to the parking position while allowing the conical member 73 to be located on the other side (-Y side) of the parking position.

[0066] Therefore, it is possible to suppress the rotation of the connecting shaft 80 from being hindered, and it is possible to suppress the application of a load to the electric actuator 10 that rotates the connecting shaft 80 .

[0067] When the rod 72 is located at the parking position and the conical member 73 is located on the other side (-Y side) in the left-right direction relative to the parking position, the coil spring 74 is in a compressed and deformed state.

[0068] Therefore, the conical member 73 is biased toward one side in the left-right direction (toward the +Y side) by the coil spring 74. Consequently, a rotational moment in the counterclockwise direction as viewed from the other side in the left-right direction (the -Y side) is applied by the coil spring 74 to the parking lock arm 77 via the conical member 73.

[0069] Therefore, when the parking lock gear 6 rotates and the position of the tooth portion 6 a shifts, the parking lock arm 77 rotates, and the meshing portion 77 b meshes between the tooth portions 6 a .

[0070] When the stopper plate 71 rotates from the parking position to the non-parking position in accordance with the rotation of the connecting shaft 80 , the rod 72 and the conical member 73 move to the other side (−Y side) in the left-right direction.

[0071] When the conical member 73 moves to the other side in the left-right direction, the end 77c of the parking lock arm 77 lifted by the conical member 73 moves downward under its own weight and the elastic force from the coil spring not shown, and the parking lock arm 77 rotates counterclockwise around the rotation axis J3 as viewed from one side in the left-right direction (+Y side).

[0072] As a result, the meshing portion 77b of the parking lock arm 77 is separated from the parking lock gear 6 and is disengaged from the teeth 6a. Figure 2 , the parking lock arm 77 is shown in a state of being disengaged from the parking lock gear 6 .

[0073] When the parking lock arm 77 is disengaged from the parking lock gear 6 , the conical member 73 is also located in the non-parking position, and the entire movable portion 70 a is located in the non-parking position.

[0074] Specifically, the parking lock arm 77 is disengaged from the parking lock gear 6 when the movable portion 70a is in the unparked position. In the unparked position, the conical member 73 is located to the other left-right side (-Y side) of the parking lock arm 77. When the parking lock arm 77 is disengaged from the parking lock gear 6, the parking lock gear 6 is unlocked.

[0075] The base member 75 supports the movable portion 70a so that it can move in the left-right direction Y. In this embodiment, the base member 75 supports the movable portion 70a from below. The base member 75 is fixed to the inner surface of the housing 2. The base member 75 includes a base plate 75a, a support portion 75b, and a leaf spring fixing portion 75c.

[0076] In the present embodiment, the base plate 75 a is in a plate shape with its plate surface facing in the vertical direction Z.

[0077] The support portion 75b protrudes upward from the base plate 75a. The support portion 75b is the portion that contacts and supports the movable portion 70a. In this embodiment, the support portion 75b contacts the conical member 73 of the movable portion 70a from below, supporting the movable portion 70a from below.

[0078] The surface of the support portion 75b on the movable portion 70a side is an arcuate curved surface that is recessed toward the side opposite to the movable portion 70a side when viewed from the left-right direction Y. Therefore, the support portion 75b can stably support the conical member 73 having the tapered surface 73a.

[0079] The leaf spring fixing portion 75c protrudes upward from the base plate 75a. The leaf spring fixing portion 75c is, for example, in the shape of a rectangular parallelepiped. The leaf spring fixing portion 75c is located on one side (+X side) in the front-back direction relative to the support portion 75b.

[0080] The leaf spring member 76 is fixed to the leaf spring fixing portion 75c of the base member 75. In this embodiment, the leaf spring member 76 is fixed to the other end (-Y side) of the upper surface of the leaf spring fixing portion 75c in the left-right direction. The leaf spring member 76 includes a leaf spring main portion 76a and a contact portion 76b.

[0081] The leaf spring body 76a is plate-shaped with its surface facing the vertical direction Z. The leaf spring body 76a extends from the leaf spring fixing portion 75c toward the other side (-Y side) in the left-right direction. The leaf spring body 76a extends to the upper side of the stopper plate 71. The leaf spring body 76a has a slit 76c at its other end in the left-right direction.

[0082] The slit 76c penetrates the leaf spring body 76a in the vertical direction Z. The slit 76c extends in the left-right direction Y. The slit 76c extends to the other left-right end of the leaf spring body 76a, dividing the other left-right end of the leaf spring body 76a into two branches.

[0083] The contact portion 76b is provided at the other end (-Y side) of the leaf spring main body 76a in the left-right direction. In this embodiment, the contact portion 76b is a roller rotatably mounted on the leaf spring main body 76a about an axis extending in the front-rear direction X.

[0084] The contact portion 76b is provided between the front end portions of the leaf spring main body 76a which is divided into two parts by the slit 76c.

[0085] The contact portion 76b is pressed against the outer peripheral edge 71a of the stopper plate 71 by the elastic force of the leaf spring member 76. Here, the position where the outer peripheral edge 71a of the stopper plate 71 contacts the contact portion 76b is referred to as a contact position P.

[0086] The contact portion 76 b , which is in contact with the outer peripheral edge 71 a at the contact position P, is pressed against the stopper plate 71 .

[0087] When the movable portion 70a is in the parking position, the contact position P is located in the first valley 79A. Therefore, the contact portion 76b is hooked on the inner side surface of the first valley 79A in the left-right direction Y, thereby holding the stopper plate 71 and the rod 72 in the parking position.

[0088] When the movable portion 70a is in the non-parking position, the contact position P is located in the second valley portion 79B. Therefore, the contact portion 76b is hooked on the inner side surface of the second valley portion 79B in the left-right direction Y, thereby holding the stopper plate 71 and the rod 72 in the non-parking position.

[0089] When the stopper plate 71 rotates about the central axis J1 , the contact position P relatively moves from the inner side of one valley portion 79 to the other valley portion 79 across the ridge portion 71 c .

[0090] When the contact position P passes over the peak 71c, the leaf spring member 76 receives a force radially outward from the peak 71c via the contact portion 76b, causing elastic deformation. Specifically, in this embodiment, the leaf spring member 76 is an elastic member that is elastically deformed by being pressed upward by the peak 71c of the stop plate 71 when the movable portion 70a moves between the non-parking position and the parking position.

[0091] As described above, the leaf spring member 76 in the present embodiment is an elastic member having the contact portion 76 b , and the contact portion 76 b contacts any one of the plurality of valley portions 79 due to the elastic force generated by the rotation of the stopper plate 71 .

[0092] In the present embodiment, when the contact portion 76 b moves between the first valley portion 79A and the second valley portion 79B, the contact portion 76 b as a roller moves while rolling on the upper end surface of the stopper plate 71 .

[0093] The contact portion 76 b is a stopper roller that moves along the outer peripheral edge 71 a of the stopper plate 71 and maintains the stopper plate 71 in the parking position or the non-parking position.

[0094] The electric actuator 10 drives the switching mechanism 70 based on the vehicle's shift operation. In this embodiment, the electric actuator 10 drives the switching mechanism 70 by moving the movable portion 70a in the left-right direction Y via the connecting shaft 80, thereby switching the parking lock gear 6 between the locked state and the unlocked state.

[0095] More specifically, the electric actuator 10 drives the stopper plate 71 to rotate about the central axis J1 perpendicular to the surface 71 f , thereby changing the contact position P of the leaf spring member 76 having the contact portion 76 b in contact with the outer peripheral edge 71 a .

[0096] Figure 3 It is a cross-sectional view of the electric actuator 10 .

[0097] The electric actuator 10 includes a housing 10A, a motor 20 , a speed reducer 30 , an output shaft 46 , a first bearing 51 , a second bearing 52 , a third bearing 53 , a control unit 90 , a rotation sensor 95 , a sensor magnet 45 , and a current sensor 96 .

[0098] The first bearing 51 , the second bearing 52 , and the third bearing 53 are, for example, ball bearings.

[0099] The housing 10A accommodates various parts of the electric actuator 10 including the motor 20 , the speed reducer 30 , and the output shaft 46 . The housing 10A includes a housing body 11 and a cover member 12 .

[0100] The housing body 11 has a cylindrical shape centered on the central axis J1. The housing body 11 has an opening 11h that opens on one side in the axial direction. The housing body 11 has a first housing portion 11a and a second housing portion 11b.

[0101] The first housing portion 11a is the other axially side portion of the housing body 11. The first housing portion 11a includes a bottom plate portion 11c located on the other axially side and a peripheral wall portion 11d extending from a radially outer edge of the bottom plate portion 11c toward one axial side.

[0102] The bottom plate portion 11c is provided with a hole portion 11e that penetrates the bottom plate portion 11c in the axial direction. The hole portion 11e is a substantially circular hole centered on the central axis J1.

[0103] A portion on one side in the axial direction of the hole 11e constitutes a first bearing holding portion 11f that holds the first bearing 51. The first bearing 51 is held by the first bearing holding portion 11f.

[0104] The second housing portion 11b is located on one axial side of the housing body 11. It is axially connected to the first housing portion 11a. The second housing portion 11b is cylindrical and open on one axial side. The inner circumference of the second housing portion 11b is provided with a stepped surface 11g facing one axial side.

[0105] The cover member 12 is fixed to one axial end portion of the housing body 11. The cover member 12 closes the opening 11h of the housing body 11 from one axial end portion.

[0106] The cover member 12 includes a cover body portion 12 a that closes the opening portion 11 h from one axial side, and a second bearing holding portion 12 b that protrudes from the cover body portion 12 a to the other axial side.

[0107] The second bearing holding portion 12b has a cylindrical shape centered on the central axis J1 and open to the other axial side. The second bearing 52 is held on the inner peripheral surface of the second bearing holding portion 12b.

[0108] The motor 20 is, for example, a three-phase brushless DC motor and includes a rotor 21 and a stator 22 .

[0109] The rotor 21 is rotatable about the central axis J1 and includes a motor shaft 23, a rotor core 24a, and a magnet 24b.

[0110] The motor shaft 23 is rotatable about the central axis J1. The motor shaft 23 is substantially cylindrical and extends in the axial direction about the central axis J1. The motor shaft 23 is a hollow shaft.

[0111] The motor shaft 23 is open on both sides in the axial direction. The motor shaft 23 extends across the interior of the first housing portion 11a and the interior of the second housing portion 11b. The motor shaft 23 includes a main body portion 23a and an eccentric shaft portion 23b.

[0112] The main body 23a is the axially facing portion of the motor shaft 23. The rotor core 24a is fixed to the outer circumferential surface of the main body 23a. The axial end of the main body 23a is located within the second housing portion 11b. The portion of the main body 23a other than the axial end is located within the first housing portion 11a.

[0113] The eccentric shaft portion 23b is the portion on the other axial side of the motor shaft 23. It is axially connected to the main body portion 23a. It is located inside the first housing portion 11a. It is located axially on the other side of the rotor core 24a.

[0114] The inner circumference of the eccentric shaft portion 23b is a circle centered on the central axis J1 when viewed from the axial direction. The outer circumference of the eccentric shaft portion 23b is a circle centered on the eccentric axis J2 eccentric to the central axis J1 when viewed from the axial direction.

[0115] The eccentric axis J2 is a virtual axis parallel to the central axis J1. The inner ring of the third bearing 53 is fitted and fixed to the outer circumferential surface of the eccentric shaft portion 23b. This secures the third bearing 53 to the motor shaft 23. The eccentric shaft portion 23b rotates eccentrically as the rotor 21 rotates about the central axis J1. In other words, the motor 20 includes an eccentric shaft portion 23b that rotates eccentrically.

[0116] The rotor core 24a has an annular shape centered on the central axis J1. The rotor core 24a is disposed inside the first housing portion 11a and is fixed to the outer peripheral surface of the main body portion 23a.

[0117] The magnet 24b is fixed to the outer peripheral surface of the rotor core 24a. In this embodiment, a plurality of magnets 24b are arranged at intervals in the circumferential direction.

[0118] The stator 22 is arranged to face the rotor 21 in the radial direction. The stator 22 is arranged radially outside the rotor 21 with a gap therebetween. The stator 22 is arranged inside the first housing portion 11a.

[0119] The stator 22 includes an annular stator core 22a surrounding the rotor core 24a from the radially outer side, an insulator 22b attached to the stator core 22a, and a plurality of coil portions 22c attached to the stator core 22a via the insulator 22b.

[0120] The outer peripheral surface of the stator core 22a is fixed to the inner peripheral surface of the peripheral wall portion 11d. Thus, the stator 22 is fixed to the housing 10A.

[0121] The speed reducer 30 is arranged inside the first housing portion 11 a . The speed reducer 30 is arranged on the other axial side of the rotor core 24 a and the stator 22 . The speed reducer 30 is connected to the motor shaft 23 and the output shaft 46 .

[0122] The speed reducer 30 reduces the speed of the rotation of the motor 20 and transmits the speed to the output shaft 46 , thereby rotating the output shaft 46 about the central axis J1 . The speed reducer 30 includes an external gear 31 , an internal gear 32 , a flange 42 , and a plurality of protrusions 43 .

[0123] The externally toothed gear 31 is annular in shape, centered on the eccentric axis J2. It engages with the outer ring of the third bearing 53. The externally toothed gear 31 is connected to the eccentric shaft portion 23b of the motor shaft 23 via the third bearing 53. This transmits the rotation of the motor shaft 23 to the externally toothed gear 31. The externally toothed gear 31 is rotatable relative to the motor shaft 23 about the eccentric axis J2.

[0124] Figure 4 It is a front view of the speed reducer 30 .

[0125] The speed reducer 30 of this embodiment is an internal speed reducer. In this specification, an “internal speed reducer” refers to a speed reducer that includes an external gear 31 and an internal gear 32 and reduces rotation when the meshing position of the external gear 31 and the internal gear 32 moves circumferentially.

[0126] The external gear 31 has a plurality of through-hole portions 31b and an external gear portion 31c. In this embodiment, the plurality of through-hole portions 31b are holes that penetrate the external gear 31 in the axial direction.

[0127] Each of the plurality of through-hole portions 31b is circular in a plan view from the axial direction. The plurality of through-hole portions 31b are arranged around the central axis J1. In this embodiment, eight through-hole portions 31b are provided.

[0128] The external gear portion 31c is provided along the outer peripheral surface of the external gear 31. The external gear portion 31c is composed of a plurality of external tooth portions 31d arranged along the outer peripheral surface of the external gear 31.

[0129] In this embodiment, the external gear portion 31c is composed of 79 external tooth portions 31d. The number of teeth N1 of the external gear portion 31c may be 78 or less, or 80 or more. The tooth profile of each external gear 31 is an involute tooth profile.

[0130] Figure 4 The first imaginary line L1 shown is an imaginary line connecting the eccentric axis J2 and the node 31f of the external tooth portion 31d when viewed from above in the axial direction. The first imaginary line L1 is a straight line perpendicular to the eccentric axis J2.

[0131] like Figure 4 As shown, the pitch point 31 f is a portion of the tooth surface of the external tooth portion 31 d that contacts the internal tooth portion 32 b of the internal gear 32 , which will be described later.

[0132] The first tangent line L3 is a tangent line that is tangent to the pitch point 31f among the tangent lines that are tangent to the tooth surface of the external tooth portion 31d. The angle formed by the first imaginary line L1 and the first tangent line L3 is the pressure angle α1 of the external tooth portion 31d.

[0133] The pressure angle α1 is the pressure angle of the tooth profile of the externally toothed gear 31. In the present embodiment, the pressure angle α1 of each of the plurality of externally toothed tooth portions 31d is not less than 22° and not more than 25.5°.

[0134] The internal gear 32 is arranged radially outside the external gear 31. The internal gear 32 surrounds the external gear 31 from the radial outside. The internal gear 32 has an annular shape centered on the central axis J1.

[0135] like Figure 3 As shown in FIG. 1 , the outer peripheral surface of the internal gear 32 is fixed to the inner peripheral surface of the peripheral wall portion 11d. That is, the internal gear 32 is fixed to the housing 10A. Figure 4 As shown, the internally-toothed gear 32 has an internally-toothed gear portion 32 a .

[0136] The internal gear portion 32a is provided along the inner peripheral surface of the internal gear 32. The internal gear portion 32a is composed of a plurality of internal tooth portions 32b arranged along the inner peripheral surface of the internal gear 32.

[0137] In this embodiment, the internal gear portion 32a is composed of 80 internal gear portions 32b. The number of teeth N2 of the internal gear portion 32a may be 79 or less, or 81 or more.

[0138] A portion of the internal gear portion 32a meshes with a portion of the external gear portion 31c. That is, the internal gear 32 meshes with at least a portion of the external gear 31. In this embodiment, the tooth profile of the internal gear 32 is an involute tooth profile.

[0139] Figure 4 The second imaginary line L2 shown is an imaginary line connecting the central axis J1 and the node 32d of the internal tooth portion 32b when viewed from above in the axial direction. The second imaginary line L2 is a straight line perpendicular to the central axis J1.

[0140] like Figure 4 As shown, the pitch point 32d is a portion of the tooth surface of the internal tooth portion 32b that contacts the pitch point 31f of the external tooth portion 31d.

[0141] The second tangent line L4 is a tangent line that is tangent to the pitch point 32d among the tangent lines that are tangent to the tooth surface of the internal tooth portion 32b. The angle formed by the second imaginary line L2 and the second tangent line L4 is the pressure angle α2 of the internal tooth portion 32b.

[0142] The pressure angle α2 is the pressure angle of the tooth profile of the internal gear 32. In the present embodiment, the pressure angle α2 of each of the plurality of internal tooth portions 32b is not less than 22° and not more than 25.5°.

[0143] The pressure angle α1 and the pressure angle α2 may be the same angle as each other, or may be different angles from each other. In the present embodiment, the pressure angle α1 and the pressure angle α2 are the same angle as each other.

[0144] like Figure 3 As shown, the flange portion 42 is arranged on the other axial side of the externally toothed gear 31. The flange portion 42 is arranged axially spaced apart from the externally toothed gear 31. The flange portion 42 has an annular shape centered on the central axis J1.

[0145] The flange portion 42 is fixed to a portion of the output shaft 46 that is located on the other side in the axial direction relative to the motor shaft 23. The flange portion 42 is provided with a plurality of protrusions 43.

[0146] In the present embodiment, the plurality of protrusions 43 are cylindrical and protrude axially to one side from the flange 42. In the present embodiment, the plurality of protrusions 43 and the flange 42 are part of the same single component.

[0147] like Figure 4 As shown in FIG. 1 , the outer diameter of each of the plurality of protrusions 43 is smaller than the inner diameter of each of the plurality of through-hole portions 31 b . The plurality of protrusions 43 are arranged around the central axis J1 .

[0148] In this embodiment, eight protrusions 43 are provided. Figure 3 As shown, the plurality of protrusions 43 are respectively inserted into each of the plurality of through-hole portions 31 b from the other axial side. like Figure 4 As shown, each protrusion 43 supports the external gear 31 via the inner side surface of the through-hole portion 31 b so as to be swingable about the central axis J1 .

[0149] The output shaft 46 outputs the driving force of the electric actuator 10 to the switching mechanism 70 via the connecting shaft 80. Figure 3 As shown, the output shaft 46 extends axially about the central axis J1 . The output shaft 46 is rotatable about the central axis J1 . The rotation of the motor shaft 23 is transmitted to the output shaft 46 via the speed reducer 30 .

[0150] The output shaft 46 axially passes through the interior of the motor shaft 23. The output shaft 46 protrudes axially from the motor shaft 23 to both sides. In other words, at least a portion of the output shaft 46 is located inside the motor shaft 23. Alternatively, the output shaft 46 and the flange portion 42 may be part of the same single component.

[0151] The output shaft 46 includes an output shaft body 41 and a mounting member 44 fixed to the outer peripheral surface of the output shaft body 41 .

[0152] The output shaft body 41 extends in the axial direction. The output shaft body 41 is supported by a first bearing 51 and a second bearing 52 so as to be rotatable about the central axis J1. The output shaft body 41 includes a connecting portion 41a and an extending portion 41b.

[0153] The connecting portion 41a is a portion on the other axial side of the output shaft body 41. The connecting portion 41a has a cylindrical shape extending in the axial direction around the central axis J1. The connecting portion 41a opens to the other axial side.

[0154] The other axial end of the connecting portion 41a is inserted into the hole 11e. The one axial end of the connecting portion 41a is inserted into the eccentric shaft portion 23b. The connecting portion 41a is supported by the first bearing 51 so as to be rotatable about the central axis J1.

[0155] The end portion 81 of the connecting shaft 80 can be inserted into the connecting portion 41a from the other axial side. The connecting portion 41a and the connecting shaft 80 are connected to each other by fitting a plurality of spline grooves provided on the outer circumferential surface of the end portion 81 of the connecting shaft 80 with a plurality of spline grooves provided on the inner circumferential surface of the connecting portion 41a.

[0156] The output shaft 46 is connected to the stopper plate 71 (see Figure 2 The rotation of the output shaft 46 is transmitted to the stopper plate 71 via the connecting shaft 80. As a result, the electric actuator 10 drives the switching mechanism 70.

[0157] The extension portion 41b is an axially oriented portion of the output shaft body 41. The extension portion 41b is cylindrical and extends axially about the central axis J1. The extension portion 41b is axially connected to the connecting portion 41a. The extension portion 41b axially extends through the interior of the motor shaft 23.

[0158] The portion of the extending portion 41b on one axial side protrudes further axially than the motor shaft 23. The end portion of the extending portion 41b on one axial side is supported by the second bearing 52 so as to be rotatable about the central axis J1.

[0159] As described above, the coupling portion 41 a is supported by the first bearing 51 so as to be rotatable about the central axis J1 .

[0160] In this embodiment, the outer diameter of the extension portion 41b is slightly smaller than the inner diameter of the main body portion 23a of the motor shaft 23. The extension portion 41b is loosely fitted within the main body portion 23a. The radial clearance between the extension portion 41b and the main body portion 23a is small enough to allow the extension portion 41b to support the motor shaft 23 for rotation about the central axis J1.

[0161] Therefore, the motor shaft 23 is supported by the housing 10A via the output shaft 46, the first bearing 51, and the second bearing 52. This can suppress radial movement of the motor shaft 23 relative to the housing 10A.

[0162] The mounting member 44 is fixed to a portion of the outer peripheral surface of the extending portion 41b that is located axially on the one side relative to the motor shaft 23. The mounting member 44 includes a fixed cylindrical portion 44a and an annular portion 44b.

[0163] The fixed cylindrical portion 44a has a cylindrical shape centered on the central axis J1 and open on both sides in the axial direction. The fixed cylindrical portion 44a is fixed to the outer peripheral surface of the extending portion 41b.

[0164] The annular portion 44 b has a substantially annular plate shape that expands radially outward from the other axial end portion of the fixed cylindrical portion 44 a .

[0165] The sensor magnet 45 is annular and surrounds the central axis J1. The sensor magnet 45 is fixed to the outer circumference of the fixed cylindrical portion 44a. The radially outer edge of the sensor magnet 45 is located radially outward of the annular portion 44b and axially faces the rotation sensor 95.

[0166] In the axial direction, a washer 61 is arranged between the other axial end portion of the main body portion 23 a of the motor shaft 23 and the one axial end portion of the connecting portion 41 a of the output shaft 46 .

[0167] The washer 61 is an annular plate that surrounds the extension portion 41b. The plate surface of the washer 61 faces the axial direction. The washer 61 axially contacts the main body portion 23a and the connecting portion 41a. Furthermore, a washer 62 is axially positioned between the axial end of the main body portion 23a and the annular portion 44b.

[0168] The washer 62 is an annular plate that surrounds the extension portion 41b. The plate surface of the washer 62 faces the axial direction. The washer 62 contacts the main body portion 23a and the annular portion 44b in the axial direction. The washers 61 and 62 are, for example, sliding washers.

[0169] The control unit 90 controls the motor 20. The control unit 90 is disposed on one axial side of the stator 22. The control unit 90 includes a substrate 91 and a plurality of components (not shown) mounted on the substrate 91.

[0170] The substrate 91 is fixed to the stepped surface 11g of the housing 10A. The substrate 91 is in the shape of a plate extending in the radial direction. An inverter circuit for supplying power to the motor 20 is provided on the substrate 91 and the components mounted on the substrate 91.

[0171] Although not shown in the figure, the substrate 91 is electrically connected to each of the plurality of coil portions 22c of the stator 22. The control unit 90 controls the power supplied to each of the plurality of coil portions 22c. The substrate 91 is provided with a through hole 91a.

[0172] The through hole 91a is circular in shape with the central axis J1 as the center when viewed from above in the axial direction. The extending portion 41b of the output shaft 46 passes through the through hole 91a in the axial direction.

[0173] A rotation sensor 95 and a current sensor 96 are mounted on the substrate 91 . That is, the control unit 90 is connected to the rotation sensor 95 and the current sensor 96 .

[0174] The control unit 90 controls the motor 20 based on the detection result of the rotation angle by the rotation sensor 95 and the detection result of the current value by the current sensor 96 .

[0175] The rotation sensor 95 is fixed to the peripheral edge of the through hole 91a in the axially one-side surface of the control portion 90. The rotation sensor 95 is axially opposed to the radially outer edge of the sensor magnet 45 fixed to the output shaft 46.

[0176] In this embodiment, rotation sensor 95 is a magnetic sensor. Rotation sensor 95 is, for example, a Hall element such as a Hall IC. Rotation sensor 95 detects the rotation of sensor magnet 45 by detecting the magnetic field of sensor magnet 45. Thus, rotation sensor 95 detects the rotation angle of output shaft 46.

[0177] The rotation sensor 95 may also be a sensor that detects the rotation angle of the motor shaft 23. In this case, the rotation sensor 95 calculates the rotation angle of the connecting shaft 80 based on the detected rotation angle of the motor shaft 23 and the reduction ratio of the speed reducer 30. In other words, the rotation sensor 95 may also indirectly detect the rotation angle of the output shaft 46.

[0178] The current sensor 96 detects the current value flowing through the motor 20 . The current sensor 96 is a current sensor using a shunt resistor, for example. The current value flowing through the motor 20 is the current value supplied by the control unit 90 to the stator 22 .

[0179] The current value flowing through the motor 20 is correlated with the torque output by the rotor 21 of the motor 20. By monitoring the current value flowing through the stator 22, the control unit 90 can monitor the reaction force applied to the rotor 21 when the rotor 21 rotates.

[0180] Furthermore, the control unit 90 preferably applies a low-pass filter to the detection value of the current sensor 96 to remove noise. The detection value of the current sensor 96 may be superimposed with noise caused by the surface roughness of the gears and magnetic pulsation between the rotor 21 and the stator 22. By including a low-pass filter in the control unit 90, it is possible to suppress the control unit 90 from erroneously detecting the current value due to such noise.

[0181] When power is supplied to the motor 20 from the control unit 90 and the motor shaft 23 rotates about the central axis J1, the eccentric shaft portion 23b revolves circumferentially about the central axis J1. The revolving eccentric shaft portion 23b is transmitted to the external gear 31 via the third bearing 53.

[0182] The externally toothed gear 31 orbits around the central axis J1 while changing the position at which the inner circumferential surface of the through-hole portion 31b contacts the outer circumferential surface of the protrusion 43. As the externally toothed gear 31 orbits around the central axis J1, the meshing position between the externally toothed gear portion 31c of the externally toothed gear 31 and the internally toothed gear portion 32a of the internally toothed gear 32 changes circumferentially. This allows the driving force of the motor shaft 23 to be transmitted to the internally toothed gear 32 via the externally toothed gear 31.

[0183] As described above, the internal gear 32 is fixed to the housing 10A. Therefore, the external gear 31 rotates about the eccentric axis J2 due to the reaction force of the driving force transmitted to the internal gear 32. At this time, the rotation of the external gear 31 is reduced relative to the rotation of the motor shaft 23.

[0184] In the structure of the speed reducer 30 of this embodiment, the reduction ratio of the rotation of the output shaft 46 relative to the rotation of the motor shaft 23, that is, the reduction ratio R of the speed reducer 30, is expressed as R = (N2 - N1) / N1. As described above, in this embodiment, the number of teeth N1 of the external gear portion 31c is 79, and the number of teeth N2 of the internal gear portion 32a is 80.

[0185] Therefore, the reduction ratio R in this embodiment is 1 / 79. According to the speed reducer 30 of this embodiment, the reduction ratio R of the rotation of the output shaft 46 relative to the rotation of the motor shaft 23 can be relatively large, and the rotational torque of the output shaft 46 can be increased relative to the rotational torque of the motor shaft 23.

[0186] The rotation of the externally toothed gear 31 about the eccentric axis J2 is transmitted to the flange portion 42 via the inner side surface of the through-hole portion 31 b and the protrusion 43 , causing the flange portion 42 to rotate about the central axis J1 .

[0187] As described above, the output shaft 46 is fixed to the flange portion 42. Therefore, the output shaft 46 rotates together with the flange portion 42 about the central axis J1. In other words, the flange portion 42 transmits the rotation of the externally toothed gear 31 to the output shaft 46. In this way, the rotation of the motor shaft 23 is transmitted to the output shaft 46 via the speed reducer 30.

[0188] along with Figure 4 As the pressure angle α1 of the outer tooth portion 31d increases, the tooth surface of the outer tooth portion 31d faces radially outward. On the other hand, as the pressure angle α2 of the inner tooth portion 32b increases, the tooth surface of the inner tooth portion 32b faces radially inward.

[0189] Therefore, as the pressure angles α1 and α2 increase, the circumferential component of the force applied from the external tooth portion 31d to the internal tooth portion 32b decreases. Consequently, the circumferential component of the reaction force applied from the internal tooth portion 32b to the external tooth portion 31d decreases, reducing the rotational torque of the external gear 31 about the eccentric axis J2. In other words, as the pressure angles α1 and α2 increase, the drive transmission efficiency between the external gear 31 and the internal gear 32 decreases.

[0190] According to this embodiment, as described above, the pressure angle α1 of the plurality of externally toothed portions 31d and the pressure angle α2 of the plurality of internally toothed portions 32b are set to 25.5° or less. Therefore, it is possible to suppress an excessive decrease in the drive transmission efficiency between the externally toothed gear 31 and the internally toothed gear 32, thereby suppressing an excessive decrease in the drive efficiency of the electric actuator 10.

[0191] In this embodiment, during reverse driving of the electric actuator 10, a rotational torque is applied to the output shaft 46, causing the output shaft 46 to rotate about the central axis J1. The rotation of the output shaft 46 is transmitted to the motor shaft 23 via the speed reducer 30, thereby driving the motor shaft 23 about the central axis J1. In this embodiment, during reverse driving, the power supply from the control unit 90 to the stator 22 is stopped.

[0192] Here, when the pressure angle α1 and the pressure angle α2 are both greater than 22°, the reverse driving torque of the electric actuator 10 becomes too large, and thus the electric actuator 10 cannot be reverse driven. The reverse driving torque is a rotational torque applied to the output shaft 46 and is a rotational torque required to reverse drive the electric actuator 10.

[0193] The tooth profiles of the external gear 31 and the internal gear 32 are involute. Furthermore, the pressure angle α1 of the tooth profile of the external gear 31 and the pressure angle α2 of the tooth profile of the internal gear 32 are 22° or greater. Therefore, reverse driving of the electric actuator 10 can be suppressed.

[0194] Even when the number of teeth of the external gear portion 31 c and the number of teeth of the internal gear portion 32 a are different from those in the present embodiment, the reverse driving of the electric actuator 10 can be similarly suppressed by setting the pressure angles α1 and α2 to 22° or more.

[0195] Regardless of the number of teeth of the external gear portion 31c and the internal gear portion 32a, when the pressure angles α1 and α2 are greater than 22°, the component of the force applied to the external gear 31 that presses the external gear 31 against the motor shaft 23 is greater than the component that moves the external gear 31 in the direction of disengagement between the external gear portion 31d and the internal gear portion 32b and causes the external gear 31 to revolve around the center axis J1. Therefore, the electric actuator 10 can be prevented from performing reverse driving.

[0196] When the pressure angles α1 and α2 are greater than 22°, the greater the reverse driving rotational torque applied to the output shaft 46, the stronger the reaction force of the force pressing the external gear 31 against the motor shaft 23 causes the external tooth portion 31d and the internal tooth portion 32b to mesh with each other, so the reverse driving torque is infinite, which can suppress the electric actuator 10 from performing reverse driving.

[0197] Next, a control method of the control unit 90 according to the present embodiment will be described. The electric actuator 10 assembled in the switching mechanism 70 performs a self-learning process.

[0198] During the self-learning process, the control unit 90 stores the rotation angle (bottom position rotation angle) of the stopper plate 71 when the contact portion 76b is located at the bottom 79ca of the first valley portion 79A (first bottom portion) and the bottom 79cb of the second valley portion 79B (second bottom portion). The stored bottom position rotation angle is used to control the rotation angle of the output shaft 46.

[0199] Figure 5 It is a schematic diagram of the stopper plate 71 and the contact portion 76b of the present embodiment, and shows an initial state of the learning process. Figure 6 Schematic diagram of the stopper plate 71 and the contact portion 76 b according to the present embodiment, illustrating a first acquisition step in the first valley portion acquisition step of the learning process.

[0200] exist Figure 5 and Figure 6 In FIG. 1 , one side in the circumferential direction (one outer peripheral edge) is indicated by +θ, and the other side in the circumferential direction (the other outer peripheral edge) is indicated by −θ.

[0201] like Figure 5 As shown, the first valley portion 79A of the stopper plate 71 includes a first bottom portion (bottom portion) 79ca, a first inclined surface (inclined surface) 79d, and a second inclined surface (inclined surface) 79e.

[0202] The first bottom portion 79ca is a portion perpendicular to the radial direction of the central axis J1.

[0203] The first inclined surface 79d extends continuously on one circumferential side (+θ) of the first bottom portion 79ca. That is, the first inclined surface 79d extends continuously from the first bottom portion 79ca to one outer peripheral edge of the first bottom portion 79ca (on the side of the outer peripheral edge 71a).

[0204] The second inclined surface 79e extends continuously from the first bottom portion 79ca to the other circumferential side (-θ). That is, the second inclined surface 79e extends continuously from the first bottom portion 79ca to the other outer peripheral edge of the first bottom portion 79ca (the other side of the outer peripheral edge 71a). The first inclined surface 79d and the second inclined surface 79e are each smoothly curved.

[0205] In the first valley portion 79A, the first inclined surface 79d and the second inclined surface 79e are line-symmetrical with respect to a reference line L5 passing through the first bottom portion 79ca and the central axis J1 when viewed in plan from the axial direction.

[0206] In the following description, the "inclination angle" of each portion of the outer peripheral edge 71a of the stopper plate 71 refers to the angle of each portion relative to the circumferential direction (a direction perpendicular to the radial direction) when the stopper plate 71 is viewed from the axial direction. The inclination angle of the first valley 79A at the first bottom 79ca is 0°.

[0207] The first inclined surface 79d has a first region 79da and a second region 79db.

[0208] First region 79da is located closer to first bottom portion 79ca than second region 79db. First region 79da is continuous with first bottom portion 79ca. First region 79da is a concavely curved surface that is radially inwardly recessed. The center of curvature of first region 79da is located radially outward of outer peripheral edge 71a. The inclination angle of first region 79da gradually increases as it moves away from first bottom portion 79ca.

[0209] Second region 79db is located further from first bottom portion 79ca than first region 79da. Second region 79db is a curved surface that is convex radially outward. The center of curvature of second region 79db is located radially inward of outer peripheral edge 71a. The inclination angle of second region 79db gradually decreases as it moves away from first bottom portion 79ca.

[0210] A first boundary portion 79dc is provided between the first region 79da and the second region 79db. The first boundary portion 79dc is an inflection point where the bending direction is reversed.

[0211] The second inclined surface 79e has a third region 79ea and a fourth region 79eb.

[0212] The third region 79ea is located closer to the first bottom portion 79ca than the fourth region 79eb. The third region 79ea is continuous with the first bottom portion 79ca. The third region 79ea is a concavely curved surface that is recessed radially inward. The center of curvature of the third region 79ea is located radially outward of the outer peripheral edge 71a. The inclination angle of the third region 79ea gradually increases as it moves away from the first bottom portion 79ca.

[0213] Fourth region 79eb is located further from first bottom portion 79ca than third region 79ea. Fourth region 79eb is a curved surface that is convex radially outward. The center of curvature of fourth region 79eb is located radially inward of outer peripheral edge 71a. The inclination angle of fourth region 79eb gradually decreases as it moves away from first bottom portion 79ca.

[0214] A second boundary portion 79ec is provided between the third region 79ea and the fourth region 79eb. The second boundary portion 79ec is an inflection point where the bending direction is reversed.

[0215] In the switching mechanism 70 immediately after assembly according to the present embodiment, the contact portion 76 b is disposed inside any one of the valley portions 79 of the detent plate 71 .

[0216] In the initial state of the self-learning process for the first valley portion 79A, the contact position P is preferably located at the first bottom portion 79ca.

[0217] However, in the switching mechanism 70 immediately after assembly, the initial position of the contact position P in the initial state of the learning process may be arranged at a position deviated from the first bottom portion 79 ca due to assembly variations or the like.

[0218] In this embodiment, if Figure 5 As shown in FIG. 1 , a case will be described in which the contact position P between the contact portion 76 b and the outer peripheral edge 71 a is located in the first region 79 da of the first valley portion 79A in the initial state of the teaching process.

[0219] The self-learning process of this embodiment includes a first valley portion acquisition process and a second valley portion acquisition process.

[0220] The first valley portion acquisition step is a step of acquiring the first bottom position rotation angle of the first valley portion 79A, and the second valley portion acquisition step is a step of acquiring the second bottom position rotation angle of the second valley portion 79B.

[0221] The first valley portion acquisition step and the second valley portion acquisition step each include a first acquisition step, a second acquisition step, and a calculation step.

[0222] First, the first acquisition step in the first valley portion acquisition step will be described.

[0223] exist Figure 6 In the first acquisition step shown, the control unit 90 rotates the stopper plate 71 toward the other circumferential side (-θ) about the central axis J1 by driving the motor 20. For example, the control unit 90 rotates the stopper plate 71 toward the other circumferential side (-θ) until the contact position P exceeds the first boundary portion 79dc.

[0224] As a result, the contact position P moves relative to the stopper plate 71 toward one circumferential side (+θ) (one outer peripheral edge). Figure 6 In the illustrated first acquisition step, the contact position P moves radially outward of the central axis J1 along the first inclined surface 79d.

[0225] The control unit 90 rotates the stopper plate 71 while monitoring the rotation angle of the output shaft 46 detected by the rotation sensor 95 and the current value of the motor 20 detected by the current sensor 96. The rotation angle of the output shaft 46 refers to the rotation angle of the stopper plate 71.

[0226] In the following description, the angle at which the contact position P moves relative to the stopper plate 71 as the stopper plate 71 rotates is referred to as the “movement angle.” The movement angle of the contact position P is an angle having an absolute value equal to the rotation angle of the stopper plate 71 and opposite in sign.

[0227] Figure 7 Graph showing the relationship between the current value (absolute value) of the motor 20 and the movement angle of the contact position P around the central axis J1 in the first acquisition step.

[0228] The first acquisition step is a step in which the control unit 90 drives the motor 20 and acquires the detection angle of the rotation sensor 95 when the current value detected by the current sensor 96 exceeds the first threshold value (threshold value) Ia when the contact position P passes through the first inclined surface 79d as the first rotation angle (detection angle) θa.

[0229] As contact position P moves toward one circumferential side (+θ) along first inclined surface 79d, the reaction force exerted by contact portion 76b on stop plate 71 increases, thereby gradually increasing the current flowing through motor 20. Control unit 90 obtains the rotation sensor's detected angle when the current value exceeds a preset first threshold value Ia as first rotation angle θa.

[0230] In addition, the current value of the motor 20 in the first acquisition step increases relatively sharply when the contact position P passes through the first region 79da, and increases relatively slowly when the contact position P passes through the second region 79db.

[0231] In the present embodiment, it is preferable to set the first rotation angle θa within the first region 79da. Thus, the control unit 90 only needs to monitor for exceeding the first threshold value Ia in the region where the current value increases rapidly, making it easy to accurately determine whether the first threshold value Ia has been exceeded. Consequently, the control unit 90 can obtain a more accurate first rotation angle θa. Alternatively, the first rotation angle θa can be set within the second region 79dB.

[0232] The control unit 90 may also return the contact position P to the original position after performing the first acquisition step. Figure 5 The regression process of the initial state is shown.

[0233] Contact position P immediately after the first acquisition step is located in second region 79db of first inclined surface 79d or at a position circumferentially to one side (+θ) relative to second region 79db. During the return step, control unit 90 rotates stopper plate 71 circumferentially to one side (+θ) by a predetermined angle. More specifically, during the return step, control unit 90 rotates stopper plate 71 in the opposite direction from the first acquisition step by the same angle as the rotation of stopper plate 71 during the first acquisition step.

[0234] Thus, the control unit 90 moves the contact position P to the other side (−θ) in the circumferential direction, and moves the contact position P to the first region 79da of the first valley portion 79A.

[0235] The contact position P after the return step does not need to be exactly the same as the initial position in the first acquisition step, and may be slightly offset to one side or the other in the circumferential direction relative to the initial position. After the return step, the electric actuator 10 is ready for the second acquisition step.

[0236] Next, the second acquisition step in the first valley portion acquisition step will be described.

[0237] Figure 8 Schematic diagram of the stopper plate 71 and the contact portion 76b of this embodiment, showing the second acquisition step in the first valley acquisition step of the self-learning process. Figure 8 In FIG. 1 , one circumferential side (one outer peripheral edge) is indicated by +θ, and the other circumferential side (the other outer peripheral edge) is indicated by −θ.

[0238] exist Figure 8 In the second acquisition step shown, the control unit 90 rotates the stopper plate 71 circumferentially toward one side (+θ) about the central axis J1 by driving the motor 20. For example, the control unit 90 rotates the stopper plate 71 circumferentially toward one side (+θ) until the contact position P exceeds the second boundary portion 79ec.

[0239] As a result, the contact position P moves relative to the stopper plate 71 toward the other circumferential side (−θ), and moves radially outward of the central axis J1 along the second inclined surface 79 e via the first bottom portion 79 ca .

[0240] The control unit 90 rotates the stopper plate 71 while monitoring the rotation angle of the output shaft 46 detected by the rotation sensor 95 and the current value of the motor 20 detected by the current sensor 96 .

[0241] Figure 9 Graph showing the relationship between the current value (absolute value) of the motor 20 and the movement angle of the contact position P around the central axis J1 in the second acquisition step.

[0242] In addition, the rotation direction of the motor 20 is reversed in the first acquisition step and the second acquisition step. Therefore, the positive and negative values ​​of the measured current values ​​are reversed in the first acquisition step and the second acquisition step.

[0243] The second acquisition step is a step in which the control unit 90 drives the motor 20 to acquire the detection angle of the rotation sensor 95 when the current value detected by the current sensor 96 exceeds the second threshold value (threshold value) Ib when the contact position P passes through the second inclined surface 79e as the second rotation angle (detection angle) θb.

[0244] When the contact position P moves toward the other circumferential side (−θ) along the second inclined surface 79 e , the reaction force applied by the contact portion 76 b to the stopper plate 71 also increases, and thus the current value flowing through the motor 20 also gradually increases.

[0245] The control unit 90 acquires the detection angle of the rotation sensor 95 when the current value exceeds the preset second threshold value Ib as the second rotation angle θb.

[0246] In this embodiment, the first threshold value Ia and the second threshold value Ib are different values, but they may be the same value. The first threshold value Ia and the second threshold value Ib in the first acquisition step and the second acquisition step are appropriately set according to the shape of the first valley portion 79A.

[0247] Furthermore, the current value of the motor 20 in the second acquisition step increases relatively sharply when the contact position P passes through the third region 79ea, and increases relatively slowly when the contact position P passes through the fourth region 79eb.

[0248] In this embodiment, it is preferable to set the second rotation angle θb within the third region 79ea. Thus, the control unit 90 only needs to monitor for the current exceeding the second threshold value Ib in the region where the current value increases rapidly, making it easy to accurately determine whether the second threshold value Ib has been exceeded. Consequently, the control unit 90 can obtain a more accurate second rotation angle θb. Alternatively, the second rotation angle θb can be set within the fourth region 79eb.

[0249] Figure 10 It will Figure 7 and Figure 9 The graphs showing the relationship between the movement angle of the contact position P and the current value (absolute value) are summarized into one graph.

[0250] The control unit 90 performs a calculation step after the first acquisition step and the second acquisition step.

[0251] In the calculation step, the control unit 90 stores the rotation angle between the first rotation angle θa and the second rotation angle θb as the first bottom position rotation angle θc in a state where the contact position P is located at the first bottom portion 79ca.

[0252] In the calculation step, the control unit 90 stores an angle obtained by dividing the first rotation angle θa and the second rotation angle θb by a predetermined ratio as the first bottom position rotation angle θc.

[0253] In this embodiment, the control unit 90 sets the center angle between the first rotation angle θa and the second rotation angle θb as the first bottom position rotation angle θc of the first valley portion 79A. That is, the control unit 90 in this embodiment stores "1:1" as a preset ratio.

[0254] In the calculation step, the control unit 90 stores the angle obtained by dividing the first rotation angle θa and the second rotation angle θb at 1:1 as the first bottom position rotation angle θc. That is, the first bottom position rotation angle θc of this embodiment is expressed by the following equation. θc=(θa+θb) / 2

[0255] The first bottom position rotation angle θc stored in the present embodiment is used as a stop position of the stopper plate 71 during the operation of the switching mechanism 70 by driving the motor 20 .

[0256] As mentioned above, in Figure 5 In the initial state of the teaching process shown, the contact position P is located at a position offset from the first bottom portion 79ca and located in the first region 79da. Therefore, the contact position P after the returning process is also located in the first region 79da.

[0257] In this embodiment, during the second acquisition step, contact position P moves from first region 79da to fourth region 79eb via first bottom portion 79ca. Therefore, the angle of movement of contact position P before acquiring the second rotation angle θb in the second acquisition step is greater than the angle of movement of contact position P before acquiring the first rotation angle θa in the first acquisition step. In other words, during the first valley acquisition step, the stopper plate 71 rotates more in the second acquisition step than in the first acquisition step.

[0258] For example, in the second acquisition step of the first valley acquisition step, the control unit 90 controls the motor 20 to increase the rotation amount of the stopper plate 71 compared to the first acquisition step, thereby acquiring the second rotation angle θb. For example, if the second rotation angle θb cannot be acquired before the rotation angle of the stopper plate 71 reaches a preset target angle, the control unit 90 rotates the stopper plate 71 beyond the target angle and continues rotating the stopper plate 71 until the second rotation angle θb is acquired.

[0259] After acquiring the first bottom position rotation angle θc in the first valley portion acquisition step, the control unit 90 performs the second valley portion acquisition step. In the second valley portion acquisition step, the control unit 90 acquires the second bottom position rotation angle, that is, the bottom position rotation angle of the second valley portion 79B.

[0260] Figure 11 FIG. 7 is a schematic diagram of the stopper plate 71 and the contact portion 76b of the present embodiment, showing an example of the initial state in the second valley portion acquisition step of the self-learning step. Figure 11 In FIG. 1 , one circumferential side (one outer peripheral edge) is indicated by +θ, and the other circumferential side (the other outer peripheral edge) is indicated by −θ.

[0261] In this embodiment, after the control unit 90 implements the first valley portion acquisition process, it drives the motor 20 to rotate the stop plate 71 to one circumferential side (+θ) around the central axis J1, thereby moving the contact position P to the other circumferential side (-θ). Figure 11 The initial position of the second valley acquisition process is shown.

[0262] The second valley portion 79B includes a second bottom portion (bottom portion) 79cb, a third inclined surface (inclined surface) 79f, and a fourth inclined surface (inclined surface) 79g.

[0263] The second bottom portion 79cb is a portion perpendicular to the radial direction of the central axis J1. In the second valley portion 79B, the inclination angle of the second bottom portion 79cb is 0°.

[0264] The third inclined surface 79f extends continuously on one circumferential side (+θ) of the second bottom portion 79cb. That is, the third inclined surface 79f extends continuously from the second bottom portion 79cb to one outer peripheral edge of the second bottom portion 79cb (on the outer peripheral edge 71a side).

[0265] The fourth inclined surface 79g extends continuously to the other circumferential side (-θ) of the second bottom portion 79cb. That is, the fourth inclined surface 79g extends continuously from the second bottom portion 79cb to the other outer peripheral edge of the second bottom portion 79cb (the other side of the outer peripheral edge 71a). The third inclined surface 79f and the fourth inclined surface 79g are each smoothly curved.

[0266] In this embodiment, the first valley portion 79A and the second valley portion 79B have the same shape. That is, the first bottom portion 79ca and the second bottom portion 79cb have the same shape. The first inclined surface 79d and the third inclined surface 79f have the same shape. The second inclined surface 79e and the fourth inclined surface 79g have the same shape.

[0267] The control unit 90 estimates the second bottom position rotation angle in a state where the contact position P is located at the second bottom 79cb of the second valley 79B based on the angle information acquired in the first valley acquisition step.

[0268] Figure 11 The contact position P shown shows the initial position of the contact position P in the second valley portion acquisition step. Figure 11 The contact position P is shown at the second bottom portion 79cb.

[0269] Figure 11 The virtual contact position P1 shown is a position corresponding to the initial position of the contact position P in the first valley portion acquisition step in the second valley portion acquisition step. The virtual contact position P1 is located on the third inclined surface 79f.

[0270] In the second valley portion acquisition step, the control unit 90 performs a self-learning step using the contact position P of the second bottom portion 79cb disposed at the other circumferential side (-θ) relative to the virtual contact position P1 as an initial position.

[0271] In the second valley portion acquisition step, the control unit 90 estimates the second bottom position rotation angle based on, for example, the first rotation angle θa or the second rotation angle θb acquired in the first acquisition step.

[0272] In addition, the control unit 90 may estimate the second bottom position rotation angle based on the first bottom position rotation angle θc acquired in the first acquisition step, for example.

[0273] In the present embodiment, the control unit 90 uses the second bottom position rotation angle estimated in the second valley portion acquisition step as the initial position of the learning step.

[0274] After estimating the second bottom position rotation angle, the control unit 90 performs the first acquisition step, the second acquisition step, and the calculation step in the second valley portion acquisition step.

[0275] In the first acquisition step of the second valley acquisition step, the control unit 90 drives the motor 20 to acquire the detection angle (third rotation angle) of the rotation sensor 95 when the current value detected by the current sensor 96 exceeds the threshold (third threshold) when the contact position P passes through the third inclined surface 79f.

[0276] Specifically, the control unit 90 Figure 11 Starting from the initial state shown, the motor 20 is driven to rotate the stopper plate 71 toward the other circumferential side (−θ) about the central axis J1 .

[0277] Thus, the contact position P moves relative to the stopper plate 71 toward one circumferential side (+θ) (one outer peripheral edge). In the first acquisition step of the second valley acquisition step, the contact position P moves radially outward of the central axis J1 along the third inclined surface 79f.

[0278] The control unit 90 rotates the stopper plate 71 while monitoring the rotation angle of the output shaft 46 detected by the rotation sensor 95 and the current value of the motor 20 detected by the current sensor 96 .

[0279] As contact position P moves toward one circumferential side (+θ) along third inclined surface 79f, the reaction force exerted by contact portion 76b on stop plate 71 increases, thereby gradually increasing the current flowing through motor 20. Control unit 90 obtains the angle detected by the rotation sensor when the current value exceeds a preset third threshold value as the third rotation angle.

[0280] In the second valley portion acquisition process, after executing the first acquisition process, the control unit 90 may return the contact position P to Figure 11 The regression process of the initial state is shown.

[0281] The contact position P immediately after the first acquisition step is located on the third inclined surface 79f or at a position circumferentially to one side (+θ) relative to the third inclined surface 79f. During the return step, the control unit 90 rotates the stopper plate 71 circumferentially to one side (+θ) by a predetermined angle. More specifically, during the return step, the control unit 90 rotates the stopper plate 71 by the same angle as the rotation angle of the stopper plate 71 during the first acquisition step of the second valley portion acquisition step, toward the side opposite to the first acquisition step of the second valley portion acquisition step.

[0282] Thus, the control unit 90 moves the contact position P to the other side (-θ) in the circumferential direction, and moves the contact position P toward the second bottom portion 79cb.

[0283] In the second valley portion acquisition step, the contact position P after the return step does not need to be exactly the same as the initial position in the first acquisition step, and can be slightly offset to one side or the other in the circumferential direction relative to the initial position. After the return step, the electric actuator 10 is ready for the second valley portion acquisition step.

[0284] In the second acquisition step of the second valley acquisition step, the control unit 90 drives the motor 20 to acquire the detection angle (fourth rotation angle) of the rotation sensor 95 when the current value detected by the current sensor 96 exceeds the threshold (fourth threshold) when the contact position P passes through the fourth inclined surface 79g.

[0285] Specifically, in the second acquisition step of the second valley portion acquisition step, the control unit 90 drives the motor 20 to rotate the stopper plate 71 toward one circumferential side (+θ) around the central axis J1 .

[0286] As a result, the contact position P moves relative to the stopper plate 71 toward the other circumferential side (−θ), and moves radially outward of the central axis J1 along the fourth inclined surface 79 g.

[0287] The control unit 90 rotates the stopper plate 71 while monitoring the rotation angle of the output shaft 46 detected by the rotation sensor 95 and the current value of the motor 20 detected by the current sensor 96 .

[0288] In the second valley portion acquisition step, similarly to the first valley portion acquisition step, the positive and negative measured values ​​of the current values ​​are reversed between the first acquisition step and the second acquisition step.

[0289] When the contact position P moves toward the other circumferential side (−θ) along the fourth inclined surface 79 g , the reaction force applied by the contact portion 76 b to the stopper plate 71 also increases, and thus the current value flowing through the motor 20 also gradually increases.

[0290] The control unit 90 acquires the detection angle of the rotation sensor 95 when the current value exceeds a preset fourth threshold value as a fourth rotation angle.

[0291] In this embodiment, the first valley portion 79A and the second valley portion 79B have the same shape. Therefore, the first threshold value Ia and the third threshold value are the same value, and the second threshold value Ib and the fourth threshold value are the same value. However, they may be different values. The third and fourth threshold values ​​in the second valley portion acquisition step are appropriately set according to the shape of the second valley portion 79B.

[0292] In the second valley portion acquisition step, the control unit 90 performs a calculation step after the first acquisition step and the second acquisition step.

[0293] In the calculation step of the second valley portion acquisition step, the control unit 90 stores the rotation angle between the third rotation angle and the fourth rotation angle as the second bottom position rotation angle in a state where the contact position P is located at the second bottom portion 79cb.

[0294] In the calculation step of the second valley portion acquisition step, the control unit 90 stores an angle obtained by dividing the third rotation angle and the fourth rotation angle at a predetermined ratio as the second bottom position rotation angle.

[0295] Here, when performing the second valley portion acquisition step, the control unit 90 estimates the second bottom portion position rotation angle based on the angle information acquired in the first valley portion acquisition step.

[0296] In the calculation step of the second valley portion acquisition step, the control unit 90 stores the rotation angle calculated based on the third rotation angle and the fourth rotation angle as the latest second bottom position rotation angle. That is, in the calculation step of the second valley portion acquisition step, the control unit 90 updates the second bottom position rotation angle based on the rotation angle between the third rotation angle and the fourth rotation angle.

[0297] In the operation of the switching mechanism 70 by driving the motor 20 , the second bottom position rotation angle updated by the control unit 90 is used as the stop position of the stopper plate 71 .

[0298] In the above-mentioned first valley portion acquisition process, if Figure 5 As shown, the initial position of the contact position P is shifted from the first bottom portion 79ca to one side (+θ) in the circumferential direction and is arranged in the first region 79da.

[0299] The initial position of contact position P during the self-learning process is preferably set at the bottom of valley portion 79 (e.g., first bottom portion 79ca). However, it may be set at a position deviated from the bottom due to assembly variations, etc. In this case, the amount of movement until the current value detected by current sensor 96 exceeds the threshold at contact position P passing through the inclined surface of valley portion 79 may increase compared to when the initial position of contact position P is at the bottom.

[0300] For example, in the second acquisition step of the first valley portion acquisition step, the control unit 90 rotates the stopper plate 71 more than in the first acquisition step when acquiring the second rotation angle θb.

[0301] In the second valley acquisition step, when the second acquisition step is performed using the virtual contact position P1 corresponding to the initial position of the contact position P in the first valley acquisition step as the initial position, the control unit 90 needs to rotate the stopper plate 71 more than in the first acquisition step when acquiring the fourth rotation angle.

[0302] Here, as described above, the control unit 90 of this embodiment estimates the second bottom position rotation angle based on the angle information acquired in the first valley acquisition step in the second valley acquisition step, and uses the estimated second bottom position rotation angle as the initial position of the self-learning step.

[0303] like Figure 11As shown, in the second valley portion acquisition step of this embodiment, the initial position of contact position P coincides with second bottom portion 79cb, or even if not coincident, is located near second bottom portion 79cb. In other words, the second bottom portion position rotation angle estimated by the control unit 90 based on the angle information acquired in the first valley portion acquisition step does not deviate significantly from second bottom portion 79cb. More specifically, the difference between the initial position in the second valley portion acquisition step and second bottom portion 79cb can be smaller than the difference between the initial position in the first valley portion acquisition step and first bottom portion 79ca.

[0304] The control unit 90 calculates, for example, based on the first rotation angle θa, the second rotation angle θb, or the first bottom position rotation angle θc. Figure 5 The initial position of the contact position P in the first valley portion acquisition step is shown.

[0305] The control unit 90 estimates the second bottom position rotation angle based on the calculated initial position of the contact position P in the first valley portion acquisition step and the shape of the stopper plate 71 .

[0306] In this embodiment, the first valley portion 79A and the second valley portion 79B have the same shape. In this embodiment, the second bottom position rotation angle is, for example, an angle obtained by adding 23° to the first bottom position rotation angle.

[0307] exist Figure 5 In the initial state of the first valley portion acquisition step shown, when the contact position P is arranged at a position offset 3° to one side (+θ) in the circumferential direction from the first bottom portion 79ca, Figure 11 The virtual contact position P1 shown is arranged at a position offset by 3° to one side (+θ) in the circumferential direction from the second bottom portion 79cb.

[0308] Therefore, the control unit 90 estimates the first bottom position rotation angle plus 26° as the second bottom position rotation angle, and uses the estimated second bottom position rotation angle as the initial position of the contact position P to perform the second valley portion acquisition step.

[0309] The control unit 90 may estimate the second bottom position rotation angle by subtracting a predetermined angle from the angle information acquired in the first valley portion acquisition step, or may estimate the second bottom position rotation angle by using a predetermined function.

[0310] Even when the switching mechanism 70 is assembled in a state where the contact position P is configured at a position deviated from the first bottom 79ca, the control unit 90 can estimate the second bottom position rotation angle based on the angle information obtained in the first valley acquisition process, thereby making the initial position of the contact position P in the second valley acquisition process consistent with the second bottom 79cb, or configured near the second bottom 79cb.

[0311] Therefore, during the second valley portion acquisition step, the control unit 90 does not need to control the motor 20 to increase the rotation amount of the stopper plate 71 according to the angle by which the initial position of the contact position P deviates from the second bottom portion 79cb. This allows the second valley portion acquisition step to be efficiently performed and the second bottom position rotation angle to be acquired. Consequently, the second valley portion acquisition step can be completed in a shorter time than the first valley portion acquisition step.

[0312] In this embodiment, the first bottom position rotation angle θc of the first valley portion 79A serves as the stop position of the stop plate 71 in the parked state and is used to control the motor 20. Meanwhile, the second bottom position rotation angle of the second valley portion 79B serves as the stop position of the stop plate 71 in the non-parked state and is used to control the motor 20.

[0313] The first valley portion 79A and the second valley portion 79B may have different shapes. When the control unit 90 estimates the second bottom position rotation angle, the predetermined angle added to or subtracted from the angle information acquired in the first valley acquisition step is set to an appropriate angle according to the shape of the stopper plate 71.

[0314] In this embodiment, the angle information acquired in the first valley portion acquisition step is used to determine the initial position of the contact position P in the second valley portion acquisition step. However, in the second valley portion acquisition step, the control unit 90 may also acquire the second bottom portion position rotation angle of the second bottom portion 79cb by performing calculations using the angle information acquired in the first valley portion acquisition step.

[0315] For example, the second valley portion acquisition step may be a step of obtaining the second bottom portion rotation angle of the second bottom portion 79cb by adding 23° to the first bottom portion rotation angle obtained in the first valley portion acquisition step. In this case, by performing only the calculation without actually driving the stopper plate 71, the rotation angle when the contact position P is located at the second bottom portion 79cb can be obtained, and the time required for the second valley portion acquisition step can be further shortened.

[0316] However, in this case, the acquired rotation angle includes dimensional errors (errors in the relative position of the second bottom portion 79cb with respect to the first bottom portion 79ca) during the manufacture of the stopper plate 71. Therefore, as in the above-described embodiment, by using the angle information acquired in the first valley portion acquisition step only for acquiring the initial position of the contact position P in the second valley portion acquisition step and performing self-learning from this initial position, it is possible to improve the accuracy of acquiring the second bottom portion position rotation angle (the rotation angle of the stopper plate 71 when the contact position P is located at the second bottom portion 79cb).

[0317] The electric actuator 10 of this embodiment is an electric actuator that rotates and drives a first plate-shaped component 71 having a surface 71f and an outer peripheral edge 71a around a central axis J1 orthogonal to the surface 71f, and changes the contact position of a second component 76 having a contact portion 76b that contacts the outer peripheral edge 71a. The electric actuator comprises: an output shaft 46 extending around the central axis J1 and connected to the first component 71; a motor 20; a reducer 30 that reduces the rotation of the motor 20 and rotates the output shaft 46 around the central axis J1; a rotation sensor 95 that detects the rotation angle of the output shaft 46; a current sensor 96 that detects the current value flowing through the motor 20; and a control unit 90 that controls the motor 20.

[0318] The outer peripheral edge 71 a has a first valley portion 79A and a second valley portion 79B. The first valley portion 79A and the second valley portion 79B have a bottom portion and two inclined surfaces connected to both sides of the bottom portion.

[0319] The control unit 90 rotates the output shaft 46 and acquires the detection angle of the rotation sensor 95 when the current value detected by the current sensor 96 exceeds a threshold value when the contact position P at the first valley portion 79A passes through the inclined surface.

[0320] In addition, the control unit 90 performs: a first valley acquisition process, which acquires the first bottom position rotation angle θc when the contact position P is located at the bottom 79ca of the first valley 79A based on the acquired detection angle; and a second valley acquisition process, which estimates the second bottom position rotation angle when the contact position P is located at the bottom 79cb of the second valley 79B based on the angle information acquired in the first valley acquisition process.

[0321] According to the electric actuator 10 of this embodiment, even if the initial position of the contact position P in the first valley portion acquisition step is located at a position deviated from the first bottom portion 79ca due to assembly deviation, the control unit 90 can correct the initial position of the contact position P in the second valley portion acquisition step based on the angle information acquired in the first valley portion acquisition step. Furthermore, in the second valley portion acquisition step, the second bottom portion position rotation angle of the second bottom portion 79cb can be calculated based on the angle information acquired in the first valley portion acquisition step.

[0322] The above configuration can shorten the time required for the second valley portion acquisition step compared to performing the first valley portion acquisition step and the second valley portion acquisition step separately. That is, it is possible to provide an electric actuator 10 that can efficiently acquire the bottom position rotation angles of the plurality of valley portions 79 of the first member 71.

[0323] The control unit 90 of the present embodiment may estimate the second bottom position rotation angle in the second valley portion acquisition step based on the detection angle of the first valley portion 79A acquired in the first valley portion acquisition step.

[0324] Even when the initial position of the contact position P in the first acquisition process is configured at a position deviated from the first bottom 79ca, the control unit 90 can efficiently acquire the second bottom position rotation angle by estimating the second bottom position rotation angle based on the detection angle of the first valley 79A, that is, the first rotation angle θa or the second rotation angle θb.

[0325] The control unit 90 of the present embodiment may estimate the second bottom position rotation angle in the second valley portion acquisition step based on the first bottom position rotation angle θc of the first valley portion 79A acquired in the first valley portion acquisition step.

[0326] Even when the initial position of the contact position P in the first acquisition process is configured at a position deviated from the first bottom 79ca, the control unit 90 can efficiently acquire the second bottom position rotation angle by estimating the second bottom position rotation angle based on the first bottom position rotation angle θc acquired in the first valley acquisition process.

[0327] The control unit 90 of this embodiment can also obtain the detection angle of one inclined surface 79d of the first valley portion 79A, that is, the first rotation angle θa, and the detection angle of another inclined surface 79e of the first valley portion 79A, that is, the second rotation angle θb, in the first valley portion acquisition process, and obtain the rotation angle between the first rotation angle θa and the second rotation angle θb as the first bottom position rotation angle θc.

[0328] The control unit 90 can appropriately set the stop position of the detent plate 71 by setting the rotation angle between the first rotation angle θa and the second rotation angle θb as the first bottom position rotation angle θc.

[0329] The control unit 90 of this embodiment may estimate the second bottom position rotation angle by adding or subtracting a predetermined angle from the angle information acquired in the first valley portion acquisition step.

[0330] The control unit 90 estimates the second bottom portion position rotation angle by adding or subtracting a predetermined angle from the angle information acquired in the first valley portion acquisition step, thereby being able to efficiently estimate the second bottom portion position rotation angle.

[0331] The control unit 90 of this embodiment may also rotate the output shaft 46 and use the second bottom position rotation angle estimated based on the angle information obtained in the first valley acquisition process as the initial position of the contact position P in the second valley acquisition process, obtain the detection angle of the rotation sensor 95 when the current value detected by the current sensor 96 exceeds the threshold when the contact position P located in the second valley 79B passes through an inclined surface 79f of the second valley 79B as the third rotation angle, obtain the detection angle of the rotation sensor 95 when the current value detected by the current sensor 96 exceeds the threshold when the contact position P located in the second valley 79B passes through another inclined surface 79g of the second valley 79B as the fourth rotation angle, and update the second bottom position rotation angle based on the rotation angle between the third rotation angle and the fourth rotation angle.

[0332] After estimating the second bottom position rotation angle based on the angle information acquired in the first valley portion acquisition step, the control unit 90 updates the second bottom position rotation angle based on the third and fourth rotation angles of the second valley portion 79B, thereby acquiring the second bottom position rotation angle with high accuracy.

[0333] While the embodiments of the present invention have been described above, the various structures and combinations thereof in the embodiments and their variations are merely examples, and additions, omissions, substitutions, and other modifications to the structures are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiments.

[0334] For example, in the above embodiment, the state where the contact portion 76b is disposed in the first valley portion 79A is set as the parking state, and the state where the contact portion 76b is disposed in the second valley portion 79B is set as the non-parking state. Figure 2 The switching mechanism 70 shown may be configured so that the state where the contact portion 76b is located in the first valley portion 79A is set as the non-parking state, and the state where the contact portion 76b is located in the second valley portion 79B is set as the parking state.

[0335] The application of the electric actuator of the present invention is not particularly limited. The structure of the speed reducer is not limited to the present embodiment. For example, as long as the external gear portion and the internal gear portion are involute gears and the pressure angle of the external gear portion and the pressure angle of the internal gear portion are both 22° or greater, the pressure angles of the external gear portion and the internal gear portion are not particularly limited.

[0336] The number of teeth on the external gear portion and the number of teeth on the internal gear portion are not particularly limited. Alternatively, multiple protrusions may be provided on the external gear portion, and multiple through-holes may be provided on the output flange portion. In this case, the multiple protrusions each protrude from the external gear portion toward the output flange portion, that is, toward the other axial side, and are inserted into the through-holes.

[0337] Furthermore, the number of protrusions and the number of through-holes provided in the transmission mechanism may each be 7 or less, or 9 or more. Furthermore, the multiple protrusions and the flange portion may be separate bodies. In this case, each of the multiple protrusions is secured to each of the multiple holes passing through the flange portion by press-fitting or the like.

[0338] Alternatively, the control unit may store the second bottom position rotation angle estimated based on the angle information acquired in the first valley portion acquisition step as the stop position of the stop plate 71 in the non-parked state. In this case, the control unit does not need to reciprocate the contact portion 76b relative to the stop plate 71 in the second valley portion acquisition step, thereby enabling a more efficient self-learning process.

[0339] Note that the present technology can adopt the following configurations. (1) An electric actuator that rotates a first plate-shaped component having a surface and an outer peripheral edge around a central axis orthogonal to the surface to change the contact position of a second component having a contact portion that contacts the outer peripheral edge, the electric actuator comprising: an output shaft extending around the central axis and connected to the first component; a motor; a reducer that reduces the rotation of the motor so that the output shaft rotates around the central axis; a rotation sensor that detects the rotation angle of the output shaft; a current sensor that detects the current value flowing through the motor; and a control unit that controls the motor, wherein the outer peripheral edge has a first valley portion and a second valley portion, and the first valley portion has a bottom part and two inclined surfaces connected to both sides of the bottom, the control unit performs the following processes: a first valley portion acquisition process, rotating the output shaft, acquiring a detection angle of the rotation sensor when the current value detected by the current sensor exceeds a threshold value when the contact position located at the first valley portion passes through the inclined surface, and acquiring a first bottom position rotation angle in a state where the contact position is located at the bottom of the first valley portion based on the acquired detection angle; and a second valley portion acquisition process, estimating a second bottom position rotation angle in a state where the contact position is located at the bottom of the second valley portion based on the angle information acquired in the first valley portion acquisition process. (2) The electric actuator according to (1), wherein, in the second valley portion acquisition step, the control unit sets the detection angle of the first valley portion acquired in the first valley portion acquisition step as the angle information. (3) The electric actuator according to (1), wherein in the second valley portion acquisition step, the control unit sets the first bottom position rotation angle of the first valley portion acquired in the first valley portion acquisition step as the angle information. (4) An electric actuator according to any one of (1) to (3), wherein, in the first valley portion acquisition process, the control unit acquires the detection angle in one of the inclined surfaces of the first valley portion, i.e., the first rotation angle, and the detection angle in another of the inclined surfaces of the first valley portion, i.e., the second rotation angle, and acquires the rotation angle between the first rotation angle and the second rotation angle as the first bottom position rotation angle. (5) The electric actuator according to any one of (1) to (4), wherein the control unit estimates the second bottom position rotation angle by adding or subtracting a predetermined angle from the angle information acquired in the first valley portion acquisition step. (6) An electric actuator according to any one of (1) to (5), wherein the control unit, after rotating the output shaft and setting the second bottom position rotation angle as the initial position of the contact position in the second valley portion acquisition process, obtains as a third rotation angle the detection angle of the rotation sensor when the current value detected by the current sensor exceeds a threshold value when the contact position located in the second valley portion passes through one of the inclined surfaces of the second valley portion, and obtains as a fourth rotation angle the detection angle of the rotation sensor when the current value detected by the current sensor exceeds a threshold value when the contact position located in the second valley portion passes through another of the inclined surfaces of the second valley portion, and updates the second bottom position rotation angle based on the rotation angle between the third rotation angle and the fourth rotation angle. Explanation of symbols

[0340] 10…electric actuator, 20…motor, 30…speed reducer, 46…output shaft, 71…stop plate (first component), 71a…outer periphery, 71f…surface, 76…leaf spring component (second component), 76b…contact portion, 79A…first valley, 79B…second valley, 79ca…bottom (first bottom), 79cb…bottom (second bottom), 79d…inclined surface (first inclined surface), 79e…inclined surface (second inclined surface), 79f…inclined surface (third inclined surface), 79g…inclined surface (fourth inclined surface), 90…control unit, 95…rotation sensor, 96…current sensor, Ia…threshold value (first threshold value), Ib…threshold value (second threshold value), J1…center axis, P…contact position, θa…first rotation angle, θb…second rotation angle, θc…first bottom position rotation angle.

Claims

1. An electric actuator that rotates a first plate-shaped member having a surface and an outer peripheral edge about a central axis perpendicular to the surface to change a contact position of a second member having a contact portion that contacts the outer peripheral edge, characterized in that: have: an output shaft extending about the central axis and connected to the first component; motor; a speed reducer that reduces the speed of the motor so as to rotate the output shaft about the central axis; a rotation sensor that detects a rotation angle of the output shaft; a current sensor configured to detect a current flowing through the motor; as well as a control unit that controls the motor, The outer periphery has a first valley portion and a second valley portion, wherein the first valley portion and the second valley portion have a bottom portion and two inclined surfaces connected to both sides of the bottom portion. The control unit performs: a first valley portion acquisition step of rotating the output shaft to acquire a detection angle of the rotation sensor when a current value detected by the current sensor exceeds a threshold value when the contact position located at the first valley portion passes through the inclined surface, and acquiring a first bottom position rotation angle when the contact position is located at the bottom of the first valley portion based on the acquired detection angle; as well as The second valley portion acquisition step estimates a second bottom position rotation angle in a state where the contact position is located at the bottom of the second valley portion based on the angle information acquired in the first valley portion acquisition step.

2. The electric actuator according to claim 1, wherein: In the second valley portion acquisition step, the control unit uses the detected angle of the first valley portion acquired in the first valley portion acquisition step as the angle information.

3. The electric actuator according to claim 1, wherein: In the second valley portion acquisition step, the control unit uses the first bottom position of the first valley portion acquired in the first valley portion acquisition step as the angle information.

4. The electric actuator according to claim 1, wherein: In the first valley portion obtaining step, The control unit acquires a first rotation angle, which is a detected angle of one of the inclined surfaces of the first valley portion, and a second rotation angle, which is a detected angle of the other inclined surface of the first valley portion. The control unit acquires a rotation angle between the first rotation angle and the second rotation angle as the first bottom position rotation angle.

5. The electric actuator according to any one of claims 1 to 4, characterized in that: The control unit estimates the second bottom position rotation angle by adding or subtracting a predetermined angle from the angle information acquired in the first valley portion acquisition step.

6. The electric actuator according to claim 5, wherein: After the control unit rotates the output shaft and sets the second bottom position as the initial position of the contact position in the second valley portion acquisition step, acquiring, as a third rotation angle, a detection angle of the rotation sensor when a current value detected by the current sensor exceeds a threshold value when the contact position located in the second valley portion passes through one of the inclined surfaces of the second valley portion; acquiring, as a fourth rotation angle, a detection angle of the rotation sensor when a current value detected by the current sensor exceeds a threshold value when the contact position located at the second valley portion passes through the other inclined surface of the second valley portion; The second bottom position rotation angle is updated based on a rotation angle between the third rotation angle and the fourth rotation angle.

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