Electric actuator

Abstract

To provide an electric actuator which enables improvement of accuracy of a position where an output shaft stops rotation.SOLUTION: An electric actuator includes: a motor part having a rotor which may rotate around a motor axis J1; and a transmission mechanism 30 having multiple gears which are rotated by rotation of the rotor being transmitted thereto. The gears include a first gear 33 and a second gear 36 which rotates in a rotation direction. The transmission mechanism 30 has: a stopper part 36e; and a contact part 35 which is disposed in a rotary movement area of the second gear 36 and may contact with the stopper part 36e. The first gear 33 has at least one of the stopper part 36e and the contact part 35. The second gear 36 has the other of the stopper part 36e and the contact part 35.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] An electric actuator including a motor, a speed reduction mechanism connected to the motor, and an output shaft to which the rotation of the motor is transmitted via the speed reduction mechanism is known. For example, Patent Document 1 discloses an electric actuator that stops the rotation of the output shaft by bringing a stopper provided on a cover into contact with a stopper provided on an output gear when the output shaft rotates within a certain range.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above electric actuator, due to assembly tolerances, dimensional tolerances, etc., the variation in the relative position between the stopper of the cover and the stopper of the output gear tends to be large. Therefore, it is difficult to improve the accuracy of the position where the rotation of the output shaft is stopped.

[0005] In view of the above circumstances, one object of the present invention is to provide an electric actuator capable of improving the accuracy of the position where the output shaft stops rotating.

Means for Solving the Problems

[0006] One embodiment of the electric actuator of the present invention comprises a motor section having a rotor rotatable about a motor shaft, and a transmission mechanism having a plurality of gears that rotate when the rotation of the rotor is transmitted to them. The plurality of gears include a first gear and a second gear that rotates in the rotational direction. The transmission mechanism has a stopper section and a contact section disposed in the rotational movement region of the second gear and capable of contacting the stopper section. The first gear has either the stopper section or the contact section. The second gear has the other of the stopper section or the contact section. [Effects of the Invention]

[0007] According to one aspect of the present invention, the precision of the position at which the output shaft stops rotating in an electric actuator can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a cross-sectional view showing an electric actuator of the first embodiment. [Figure 2] Figure 2 is a cross-sectional view showing an electric actuator of the first embodiment, and is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] Figure 3 is a perspective view showing the transmission mechanism of the first embodiment. [Figure 4] Figure 4 is a first top view showing the transmission mechanism of the first embodiment. [Figure 5] Figure 5 is a second top view showing the transmission mechanism of the first embodiment. [Figure 6] Figure 6 is a third top view showing the transmission mechanism of the first embodiment. [Figure 7] Figure 7 is a top view showing the transmission mechanism of the second embodiment. [Figure 8] Figure 8 is a top view showing the transmission mechanism of the third embodiment. [Modes for carrying out the invention]

[0009] The following description of an electric actuator according to an embodiment of the present invention will be made with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiments, and can be arbitrarily modified within the scope of the technical idea of ​​the present invention. Furthermore, in the following drawings, the scale and number of components in each structure may differ from the actual structure in order to make the components easier to understand.

[0010] In each figure, the XYZ coordinate system is shown as a three-dimensional Cartesian coordinate system where appropriate. In the XYZ coordinate system, the Z axis direction is the vertical direction. The +Z side is the vertically upward side, and the -Z side is the vertically downward side. In the following explanation, the vertically upward side will simply be referred to as "upper side," and the vertically downward side will simply be referred to as "lower side." The X-axis direction is perpendicular to the Z-axis direction and represents the left-right direction of the electric actuator. In the following embodiments, the +X side is the left side of the electric actuator, and the -X side is the right side of the electric actuator. In the following description, the left side of the electric actuator will be simply referred to as "left side," and the right side of the electric actuator will be simply referred to as "right side." The Y-axis direction is perpendicular to both the Z-axis and X-axis directions and is the front-to-back direction of the electric actuator. In the following embodiments, the +Y side is the front side of the electric actuator, and the -Y side is the rear side of the electric actuator. In the following description, the front side of the electric actuator will be simply referred to as the "front side," and the rear side of the electric actuator will be simply referred to as the "rear side." Note that the terms "upper side," "lower side," "left side," "right side," "front side," and "rear side" are merely names used to describe the relative positional relationships of each part, and the actual arrangement may differ from those indicated by these names.

[0011] The direction in which the motor shaft J1 extends, as shown appropriately in each figure, is parallel to the X-axis direction, i.e., the left-right direction. In the following explanation, the direction parallel to the motor shaft J1 will simply be referred to as the "axial direction." Also, the radial direction centered on the motor shaft J1 will simply be referred to as the "radial direction," and the circumferential direction centered on the motor shaft J1 will simply be referred to as the "circumferential direction."

[0012] The circumferential direction is indicated by the arrow θ1 in each figure. The side of the circumferential direction in which arrow θ1 points (+θ1 side) is called the "one side of the circumferential direction." The side of the circumferential direction opposite to the side in which arrow θ1 points (-θ1 side) is called the "other side of the circumferential direction." The one side of the circumferential direction is the side that moves clockwise around the motor shaft J1 when viewed from the left side (+X side). The other side of the circumferential direction is the side that moves counterclockwise around the motor shaft J1 when viewed from the left side.

[0013] <First Embodiment> The electric actuator 1 of this embodiment, shown in Figure 1, is an electric actuator mounted on a vehicle. More specifically, it is mounted on a park-by-wire actuator system that is driven based on the shift operation of the vehicle driver. As shown in Figure 1, the electric actuator 1 comprises a case 10, a motor unit 20, a transmission mechanism 30, a support member 50, a control unit 70, and a filter member 90. As shown in Figure 2, the electric actuator 1 includes an output shaft 38.

[0014] The case 10 houses the motor unit 20, the transmission mechanism 30, the output shaft 38, the support member 50, and the control unit 70. As shown in Figure 2, the case 10 houses the output shaft 38. As shown in Figure 1, the filter member 90 is attached to the case 10. The case 10 is cylindrical and surrounds the motor shaft J1. The case 10 has a housing section 11 and a lid section 17. In this embodiment, the case 10 is made of resin. Therefore, compared to the case 10 being made of metal, the increase in manufacturing cost and mass of the electric actuator 1 can be suppressed. The case 10 may also be made of a metal such as aluminum.

[0015] The housing section 11 is box-shaped and extends in the axial direction. The housing section 11 has a first opening 11a that opens to the bottom. The first opening 11a is closed by a lid 17 fixed to the lower end of the housing section 11. The housing section 11 includes a motor housing section 12 and a transmission mechanism housing section 14.

[0016] The motor housing portion 12 houses the motor portion 20 therein. The motor housing portion 12 has a first side wall portion 13 located on the right side (-X side) of the motor portion 20.

[0017] The transmission mechanism housing portion 14 houses the transmission mechanism 30 therein. The transmission mechanism housing portion 14 is disposed on the left side (+X side) of the motor housing portion 12. The transmission mechanism housing portion 14 has a second side wall portion 15 located on the left side of the transmission mechanism 30. The second side wall portion 15 has a second side wall base portion 15a, a through hole 15b, and a first protruding portion 15e. The second side wall base portion 15a is plate-shaped and extends in a direction orthogonal to the axial direction.

[0018] The through hole 15b is a hole that penetrates the second side wall base portion 15a in the axial direction. That is, the through hole 15b is a hole that penetrates the wall portion of the case 10 in the axial direction. The through hole 15b is a circular hole centered on the motor shaft J1. Through the through hole 15b, the inside and the outside of the case 10 are connected.

[0019] The first protruding portion 15e protrudes from the second side wall base portion 15a to the left side (+X side). When viewed in the axial direction, the first protruding portion 15e is circular and centered on the motor shaft J1. The first protruding portion 15e is disposed outside the through hole 15b in the radial direction.

[0020] As shown in FIG. 2, the transmission mechanism housing portion 14 has a first wall portion 14a disposed above the transmission mechanism 30, a second wall portion 14b disposed on the front side (+Y side) of the transmission mechanism 30, and a third wall portion 14c disposed on the rear side (+Y side) of the transmission mechanism 30. The first wall portion 14a is provided with an output hole 14e and a first support hole 14f.

[0021] The output hole 14e is a hole that penetrates the first wall portion 14a in the Z-axis direction. The output hole 14e is provided in the front side (+Y side) portion of the first wall portion 14a. When viewed in the Z-axis direction, the output hole 14e is circular and centered on a third axis J3 that extends in a direction orthogonal to the motor shaft J1 and parallel to the Z-axis. The first support hole 14f is a hole that is recessed upward from the lower side of the first wall portion 14a. The first support hole 14f is provided in the rear side (-Y side) of the first wall portion 14a. Viewed in the Z-axis direction, the first support hole 14f is circular in shape with the second axis J2, which is perpendicular to the motor axis J1 and extends in a direction parallel to the Z-axis, as its center.

[0022] In the following explanation, the direction parallel to the second axis J2 will simply be called the "second axis direction," the radial direction centered on the second axis J2 will simply be called the "second radial direction," and the circumferential direction centered on the second axis J2 will simply be called the "second circumferential direction." The second axis J2 is a virtual axis. The second circumferential direction is indicated by the arrow θ2 in each figure. The side of the second circumferential direction that arrow θ2 points to (+θ2 side) will be called "one side of the second circumferential direction." The side of the second circumferential direction opposite to the side that arrow θ2 points to (-θ2 side) will be called "the other side of the second circumferential direction." One side of the second circumferential direction is the side that proceeds clockwise around the second axis J2 when viewed from below (-Z side). The other side of the second circumferential direction is the side that proceeds counterclockwise around the second axis J2 when viewed from below.

[0023] In the following explanation, the direction parallel to the third axis J3 will simply be called the "third axis direction," the radial direction centered on the third axis J3 will simply be called the "third radial direction," and the circumferential direction centered on the third axis J3 will simply be called the "third circumferential direction." The third axis J3 is a virtual axis. The third circumferential direction is indicated by the arrow θ3 in each figure. The side of the third circumferential direction that arrow θ3 points to (+θ3 side) will be called "one side of the third circumferential direction." The side of the third circumferential direction opposite to the side that arrow θ3 points to (-θ3 side) will be called "the other side of the third circumferential direction." One side of the third circumferential direction is the side that proceeds clockwise around the third axis J3 when viewed from below (-Z side). The other side of the third circumferential direction is the side that proceeds counterclockwise around the third axis J3 when viewed from below (-Z side). In this embodiment, the third axis J3 extends in the direction in which the second axis J2 extends. In this embodiment, the third axis J3 is perpendicular to the motor axis J1.

[0024] As shown in Figure 1, the support member 50 supports the motor unit 20, the transmission mechanism 30, and the control unit 70. The support member 50 has a motor support portion 51, a bottom wall portion 53, a transmission mechanism support portion 55, and a substrate support portion 57. As shown in Figure 2, the support member 50 has a protruding wall portion 54.

[0025] As shown in Figure 1, the motor support portion 51 extends along the axial direction. The motor support portion 51 is positioned radially outward from the lower part of the motor portion 20. The motor support portion 51 supports the motor portion 20 via the motor case 40, which will be described later. Although not shown in the figure, the motor support portion 51 is arc-shaped, convex downwards with the motor shaft J1 as the center when viewed in the axial direction. One circumferential side (+θ1 side) and the other circumferential side (-θ1 side) of the motor support portion 51 are fixed to the motor housing portion 12. In this way, the support member 50 is fixed to the case 10.

[0026] The bottom wall portion 53 is plate-shaped and extends in a direction perpendicular to the Z-axis direction. Although not shown in the figure, the right end (+X side) of the bottom wall portion 53 is connected to the motor support portion 51 in the axial direction. The bottom wall portion 53 is located below (-Z side) the transmission mechanism 30. As shown in Figure 2, the bottom wall portion 53 has a first hole portion 53a and a second support hole 53b.

[0027] The first hole 53a is a hole that penetrates the bottom wall 53 in the Z-axis direction. The first hole 53a is provided on the front side (+Y side) of the bottom wall 53. The first hole 53a is a circular hole centered on the third axis J3. The fourth bearing 96 is held on the inner circumferential surface of the first hole 53a. The second support hole 53b is a hole that is recessed downwards from the upper surface of the bottom wall portion 53. The second support hole 53b is provided on the rear side (-Y side) of the bottom wall portion 53. When viewed in the Z-axis direction, the second support hole 53b is circular in shape with the second axis J2 as its center. When viewed in the Z-axis direction, the second support hole 53b overlaps with the first support hole 14f.

[0028] The protruding wall portion 54 is positioned on the third radially outward side of the output shaft 38. In this embodiment, the protruding wall portion 54 is positioned on the front side (+Y side) of the output shaft 38. The protruding wall portion 54 protrudes upward from the bottom wall portion 53. Although not shown in the figures, when viewed in the Z-axis direction, the protruding wall portion 54 is approximately arc-shaped with the third axis J3 as the center.

[0029] As shown in Figure 1, the transmission mechanism support portion 55 is an annular shape that protrudes upward (+Z side) from the left (+X side) end of the bottom wall portion 53. The third bearing 95 is held on the inner circumferential surface of the transmission mechanism support portion 55. The transmission mechanism support portion 55 has a fourth hole portion 55a. The fourth hole portion 55a is a hole that axially relates to the transmission mechanism support portion 55. The fourth hole portion 55a is a substantially circular hole centered on the motor shaft J1.

[0030] The substrate support portion 57 is cylindrical and protrudes in the Z-axis direction. Multiple substrate support portions 57 are provided. The multiple substrate support portions 57 include substrate support portions 57 that protrude downward from the motor support portion 51 and substrate support portions 57 that protrude downward from the bottom wall portion 53.

[0031] The motor unit 20 includes a motor case 40, a rotor 22, a stator 23, a first bearing 93, and a second bearing 94. The motor case 40 houses the rotor 22, stator 23, first bearing 93, and second bearing 94 inside. The motor case 40 includes a motor case body 41 and a lid 42.

[0032] The motor case body 41 is cylindrical, extending axially around the motor shaft J1. The motor case body 41 has openings on the left side (+X side) and the right side (-X side). The motor case body 41 surrounds the rotor 22 and stator 23 from the radially outer side. The lower part of the motor case body 41 is held by the motor support portion 51 of the support member 50. The upper part of the motor case body 41 is held by the motor housing portion 12 of the case 10. The second bearing 94 is held on the inner circumferential surface of the left side (+X side) of the motor case body 41. The cover 42 is annular, centered around the motor shaft J1. The cover 42 is fixed to the right side (-X side) end of the motor case body 41. The first bearing 93 is held on the inner circumferential surface of the right side of the cover 42.

[0033] The rotor 22 is rotatable around the motor shaft J1. The rotor 22 has a rotor core 22a, a plurality of motor magnets 22b, and a motor shaft 24. The rotation of the rotor 22 is transmitted to the transmission mechanism 30. The rotor core 22a is substantially annular in shape with the motor shaft J1 as the center. The plurality of motor magnets 22b are each fixed to the outer circumferential surface of the rotor core 22a.

[0034] The motor shaft 24 is substantially cylindrical in shape and extends axially along the motor shaft J1. The rotor core 22a is fixed to the outer surface of the motor shaft 24. The left end (+X side) of the motor shaft 24 is located inside the transmission mechanism housing 14. The left portion of the motor shaft 24 is rotatably supported by the second bearing 94. The right portion of the motor shaft 24 is rotatably supported by the first bearing 93, which is held by the cover 42. As a result, the motor shaft 24 is rotatable about the motor shaft J1.

[0035] The stator 23 is positioned radially outward from the rotor 22. The stator 23 is positioned opposite the rotor 22 with a radial gap between them. The stator 23 includes a stator core 23a, an insulator 23e mounted on the stator core 23a, and a plurality of coils 23f mounted on the stator core 23a via the insulator 23e. The stator core 23a is substantially annular in shape with the motor shaft J1 as its center. The stator core 23a is fixed to the motor case body 41. Power is supplied to the coils 23f from an external power source (not shown).

[0036] The transmission mechanism 30 is located on the left side (+X side) of the motor unit 20. The transmission mechanism 30 is connected to the motor shaft 24 and the output shaft 38. In this embodiment, the transmission mechanism 30 is a reduction mechanism that reduces the rotation of the rotor 22 and transmits it to the output shaft 38. As shown in Figure 3, the transmission mechanism 30 has a plurality of gears and an intermediate shaft 32. In this embodiment, the plurality of gears include a drive input gear 31, a drive gear 33, and a driven gear 36. The drive input gear 31, the drive gear 33, and the driven gear 36 are gears that rotate when the rotation of the rotor 22 is transmitted to them. In this embodiment, the drive input gear 31, the drive gear 33, and the driven gear 36 are each made of metal. In this embodiment, the drive input gear 31, the drive gear 33, and the driven gear 36 are each made of stainless steel. In this embodiment, the Young's modulus of the drive input gear 31, the drive gear 33, and the driven gear 36 are all greater than the Young's modulus of case 10.

[0037] In this embodiment, the transmission mechanism 30 has a plurality of gears, including a first gear and a second gear. The first gear has either a stopper portion or a contact portion, which will be described later. The second gear has either a stopper portion or a contact portion, which will be described later. That is, the transmission mechanism 30 has a stopper portion and a contact portion. The second gear rotates in the rotational direction.

[0038] As shown in Figure 1, the drive input gear 31 extends axially along the motor shaft J1. The drive input gear 31 is located on the left side (+X side) of the motor shaft 24. The drive input gear 31 is connected to the motor shaft 24. The drive input gear 31 has a drive input body portion 31a and a drive input gear portion 31d.

[0039] The drive input body 31a extends axially around the motor shaft J1. The drive input body 31a has a casing 31b and a connecting portion 31c. The casing 31b is substantially cylindrical and extends axially around the motor shaft J1. The left side (+X side) portion of the casing 31b is supported by the third bearing 95.

[0040] The connecting portion 31c protrudes to the right from the right (-X side) end of the body portion 31b. The connecting portion 31c is annular in shape with the motor shaft J1 as the center. The left (+X side) end of the motor shaft 24 is inserted into the inside of the connecting portion 31c. The connecting portion 31c and the left end of the motor shaft 24 are connected to each other. As a result, the drive input gear 31 is axially connected to the motor shaft 24. The drive input gear 31 is rotatable together with the rotor 22 around the motor shaft J1.

[0041] The drive input gear section 31d is provided on the outer circumferential surface of the body section 31b. In other words, the drive input gear section 31d is provided on the outer circumferential surface of the drive input main body section 31a. In this embodiment, the drive input gear section 31d is a worm gear that extends spirally in the axial direction. The drive input gear section 31d is rotatable around the motor shaft J1.

[0042] As shown in Figure 3, the drive gear 33 rotates about the second axis J2. The drive gear 33 is located behind (-Y side of) the drive input gear 31. The drive gear 33 transmits the rotation of the drive input gear 31 to the driven gear 36. The drive gear 33 is a two-stage gear having a first drive gear 34 and a second drive gear 35 having a smaller radius than the first drive gear 34. The drive gear 33 has a drive gear portion 33b that extends in an arc shape along the second circumferential direction, that is, the circumferential direction centered on the second axis J2. The drive gear portion 33b has a first drive gear portion 34b and a second drive gear portion 35b. The first drive gear portion 34b is provided on the first drive gear 34. The second drive gear portion 35b is provided on the second drive gear 35.

[0043] The first drive gear 34 transmits the rotation of the drive input gear 31 to the second drive gear 35. The first drive gear 34 is rotatable about the second axis J2. The first drive gear 34 has a drive gear base 34a and a first drive gear portion 34b. The drive gear base 34a is a plate-like structure with a roughly fan shape centered on the second axis J2. The plate surface of the drive gear base 34a faces in the Z-axis direction. The drive gear base 34a protrudes toward the drive input gear 31. The drive gear base 34a is provided with a hole 34e that penetrates the drive gear base 34a in the direction of the second axis. The hole 34e is a circular hole centered on the second axis J2.

[0044] The first drive gear portion 34b is provided on the outer circumferential surface of the drive gear base portion 34a. More specifically, the first drive gear portion 34b is provided on the outer circumferential surface of the tip portion of the drive gear base portion 34a that protrudes toward the drive input gear 31. In other words, the first drive gear portion 34b is provided on the outer circumferential surface of the drive gear base portion 34a, specifically in the arc portion of the substantially fan-shaped drive gear base portion 34a. The first drive gear portion 34b extends in an arc shape along the circumferential direction centered on the second axis J2. The first drive gear portion 34b has a plurality of first drive teeth portions 34c arranged in the second circumferential direction. The first drive gear portion 34b and the drive input gear portion 31d mesh with each other. As a result, the rotation of the drive input gear 31 is transmitted to the drive gear 33. The rotation of the first drive gear 34 is reduced relative to the rotation of the drive input gear 31.

[0045] The second drive gear 35 transmits the rotation of the first drive gear 34 to the driven gear 36. The second drive gear 35 is positioned above (on the +Z side of) the first drive gear 34. The second drive gear 35 is fixed to the first drive gear 34. The second drive gear 35 rotates together with the first drive gear 34 around the second axis J2. The second drive gear 35 has a second drive gear base 35a, a second drive gear portion 35b, and a shaft portion 35e.

[0046] The second drive gear base 35a is substantially annular in shape with the second axis J2 as its center. The radius of the second drive gear base 35a is smaller than the radius of the drive gear base 34a. As shown in Figure 2, the second drive gear base 35a is provided with a hole 35d that penetrates the second drive gear base 35a in the second axial direction. As shown in Figure 4, the second drive gear base 35a has a contact portion 35f. That is, the drive gear 33 has a contact portion 35f. In this embodiment, the drive gear 33 is the first gear having a contact portion 35f.

[0047] In the transmission mechanism 30 shown in Figure 4, the center position of the second drive gear section 35b in the second circumferential direction, viewed in the Z-axis direction, coincides with a virtual straight line L1 that passes through both the second axis J2 and the third axis J3. In the following description, the position of each gear in the transmission mechanism 30 when the drive gear 33 is positioned at a location that coincides with the center position of the second drive gear section 35b in the second circumferential direction and the virtual straight line L1, viewed in the Z-axis direction, is referred to as the central position P1. In the following description, the central position P1 is a reference position for explaining the position of each gear that moves due to the operation of the transmission mechanism 30, in particular the position of the contact portion and the stopper portion. Therefore, each gear in the transmission mechanism 30 does not necessarily have to stop at the central position P1; each gear in the transmission mechanism 30 may or may not stop at the central position P1.

[0048] The contact portion 35f is a part of the outer circumferential surface of the second drive gear base portion 35a. At the central position P1, the contact portion 35f is located behind (-Y side of) the second axis J2. In this embodiment, the contact portion 35f has a first contact portion 35g and a second contact portion 35h. At the central position P1, the first contact portion 35g is located to the left (+X side of) the virtual straight line L1. At the central position P1, the second contact portion 35h is located to the right (-X side of) the virtual straight line L1.

[0049] As shown in Figure 3, the second drive gear portion 35b is provided on the outer circumferential surface of the second drive gear base portion 35a. The second drive gear portion 35b is provided only on a part of the outer circumferential surface of the second drive gear base portion 35a. More specifically, the second drive gear portion 35b is provided on the portion facing the driven gear 36. The second drive gear portion 35b extends in an arc shape along the circumferential direction centered on the second axis J2. As described above, the first drive gear portion 34b extends in an arc shape along the circumferential direction centered on the second axis J2. Therefore, the drive gear 33 has a drive gear portion 33b that extends in an arc shape along the second circumferential direction. In this embodiment, the pitch radius of the second drive gear portion 35b is smaller than the pitch radius of the first drive gear portion 34b. The second drive gear portion 35b has a plurality of second drive teeth portions 35c arranged in the second circumferential direction.

[0050] As shown in Figure 2, the shaft portion 35e protrudes downward from the base portion 35a of the second drive gear. The shaft portion 35e is cylindrical with the second axis J2 as its center. The outer circumferential surface of the lower part of the shaft portion 35e is fixed to the hole portion 34e of the first drive gear 34. This fixes the first drive gear 34 and the second drive gear 35 to each other.

[0051] The intermediate shaft 32 is cylindrical in shape and extends in the direction of the second axis with respect to the second axis J2. The intermediate shaft 32 passes through the inside of the shaft portion 35e and the hole portion 35d in the Z-axis direction. The upper portion of the intermediate shaft 32 is supported by the first support hole 14f. The lower portion of the intermediate shaft 32 is supported by the second support hole 53b.

[0052] The driven gear 36 is rotatable about the third axis J3. The driven gear 36 transmits the rotation of the drive gear 33 to the output shaft 38. As shown in Figure 3, the driven gear 36 is positioned in front of the second drive gear 35 (+Y side). The driven gear 36 is positioned above the drive input gear 31 (+Z side). The driven gear 36 has a driven gear base 36a and a stopper portion 36e. In this embodiment, the driven gear 36 is a second gear having a stopper portion 36e. Also in this embodiment, the direction of rotation of the second gear is the third circumferential direction.

[0053] The driven gear base 36a protrudes toward the second driven gear 35 in the radial direction of the third axis. It has a roughly fan shape centered on the third axis J3. The third axis J3 passes through the driven gear base 36a. As shown in Figure 4, at the central position P1, the driven gear base 36a protrudes toward the rear (-Y side). As shown in Figure 3, the driven gear base 36a has a driven gear portion 36b. As shown in Figure 2, the driven gear base 36a has a hole 36d that penetrates the driven gear base 36a in the third axial direction. The hole 36d is a roughly circular hole centered on the third axis J3.

[0054] As shown in Figure 3, the driven gear portion 36b is provided on the outer circumferential surface of the driven gear base portion 36a. More specifically, as shown in Figure 4, the driven gear portion 36b is provided on the outer circumferential surface of the tip portion of the driven gear base portion 36a that protrudes toward the second drive gear 35. The driven gear portion 36b extends in an arc shape along the circumferential direction centered on the third axis J3. As described above, the drive gear 33 has a drive gear portion 33b that extends in an arc shape along the second circumferential direction. Therefore, according to this embodiment, since the drive gear portion 33b is arc-shaped, the drive gear 33 can be made smaller in the second radial direction compared to the case in which the drive gear portion 33b is provided over the entire circumference along the second circumferential direction. Furthermore, because the driven gear portion 36b is arc-shaped, the driven gear 36 can be miniaturized in the third radial direction compared to the case where the driven gear portion 36b is provided along the third circumferential direction for an entire circumference. Therefore, the transmission mechanism 30 and the electric actuator 1 can be miniaturized.

[0055] At the central position P1, the center position of the driven gear portion 36b in the third circumferential direction, viewed in the Z-axis direction, approximately coincides with the virtual straight line L1. The driven gear portion 36b has a plurality of driven teeth 36c arranged in the third circumferential direction. The driven gear portion 36b and the second drive gear portion 35b mesh with each other. That is, the driven gear portion 36b meshes with the drive gear portion 33b. As a result, the rotation of the rotor 22 is transmitted to the driven gear 36 via the drive gear 33. In addition, the rotation of the driven gear 36 is reduced relative to the rotation of the first drive gear 34.

[0056] The stopper portion 36e protrudes from the driven gear base portion 36a in the third radial direction. The stopper portion 36e has a first stopper portion 36f and a second stopper portion 36g. The first stopper portion 36f is columnar in shape and protrudes outward in the third radial direction from one end (+θ3 side) in the third circumferential direction of the driven gear base portion 36a. The first stopper portion 36f is positioned on one side in the third circumferential direction of the second drive gear 35. The first stopper portion 36f is positioned on one side in the third circumferential direction of the first contact portion 35g.

[0057] The second stopper portion 36g is columnar in shape and protrudes outward in the third radial direction from the other side (-θ3 side) of the driven gear base portion 36a in the third circumferential direction. The second stopper portion 36g is positioned on the other side of the second drive gear 35 in the third circumferential direction. The second stopper portion 36g is positioned on the other side of the second contact portion 35h in the third circumferential direction. As described above, the first stopper portion 36f is positioned on one side (+θ3 side) of the first contact portion 35g in the third circumferential direction. Thus, the first stopper portion 36f and the second stopper portion 36g are positioned with the contact portion 35f in between in the third circumferential direction.

[0058] The rotation of the motor shaft 24 is transmitted to the output shaft 38 via the transmission mechanism 30. As shown in Figure 2, the output shaft 38 extends along the third axis J3. The output shaft 38 has a shaft portion 38a, a cylindrical portion 38b, and a holding portion 38e. The shaft portion 38a is substantially cylindrical and extends along the third axis J3. In the Z-axis direction, the shaft portion 38a is located between the bottom wall portion 53 of the support member 50 and the driven gear 36.

[0059] The cylindrical portion 38b protrudes upward from the shaft portion 38a. The cylindrical portion 38b is an annular shape centered on the third axis J3. The outer circumferential surface of the lower part of the cylindrical portion 38b is fixed to the hole 36d of the driven gear 36. This connects the driven gear 36 and the output shaft 38. In other words, the output shaft 38 is connected to the transmission mechanism 30. The outer circumferential surface of the upper part of the cylindrical portion 38b is supported by the inner circumferential surface of the output hole 14e of the case 10. A groove is provided on the outer circumferential surface of the cylindrical portion 38b, and an X-ring 92 is fitted into the groove. The X-ring 92 contacts the inner circumferential surface of the output hole 14e and the outer circumferential surface of the cylindrical portion 38b, sealing the space between the case 10 and the output shaft 38.

[0060] Multiple spline grooves are provided on the inner circumferential surface of the cylindrical portion 38b along the third circumferential direction. The inner circumferential surface of the cylindrical portion 38b is connected to another member to which the driving force of the electric actuator 1 is output. In this embodiment, the other member is the manual shaft of the vehicle. The electric actuator 1 drives the manual shaft based on the driver's shift operation and switches the gears of the vehicle.

[0061] The retaining portion 38e protrudes downward from the shaft portion 38a. The retaining portion 38e is annular in shape with the third axis J3 as its center. The outer circumferential surface of the retaining portion 38e is supported by the fourth bearing 96. As described above, the cylindrical portion 38b is supported by the inner circumferential surface of the output hole 14e of the case 10. As a result, the output shaft 38 is rotatable about the third axis J3. The magnet retaining portion 98 is fixed to the inner circumferential surface of the retaining portion 38e. The magnet retaining portion 98 and the magnet 99 are positioned opposite the control unit 70 with a gap in the Z-axis direction.

[0062] The control unit 70 controls the DC current supplied to the coil 23f. As shown in Figure 1, The control unit 70 has a control board 70a. The control board 70a is plate-shaped and extends in a direction perpendicular to the Z-axis direction. The control board 70a is located below the motor unit 20 and the transmission mechanism 30. The control board 70a is supported by a support member 50 by a plurality of board support parts 57. Although not shown in the figure, the control board 70a is electrically connected to a coil 23f. Power is supplied to the coil 23f from an inverter circuit provided on the control board 70a. A sensor 76 is mounted on the upper surface of the control board 70a. The sensor 76 is a magnetic sensor capable of detecting the magnetic field of the magnet 99. By detecting the magnetic field of the magnet 99, the sensor 76 detects the rotational position of the magnet 99 and detects the rotation of the output shaft 38.

[0063] As shown in Figure 1, the first bearing 93 and the second bearing 94 are ball bearings. The first bearing 93 and the second bearing 94 may also be rolling bearings other than ball bearings, or they may be sliding bearings. The third bearing 95 and the fourth bearing 96 shown in Figure 2 are sliding bearings. The third bearing 95 and the fourth bearing 96 may also be rolling bearings.

[0064] As shown in Figure 1, the filter member 90 is installed in the through hole 15b of the case 10. The filter member 90 is a filter that allows air to pass between the inside and outside of the case 10. The filter member 90 can stabilize the air pressure inside the case 10. An O-ring 91 is placed between the filter member 90 and the inner surface of the through hole 15b. The O-ring 91 contacts the filter member 90 and the inner surface of the through hole 15b, sealing the space between the filter member 90 and the case 10.

[0065] Next, a configuration in the electric actuator 1 of this embodiment that suppresses the rotation of the output shaft 38 beyond a certain range will be described. First, as shown in Figure 4, we will describe the case where the drive gear 33 rotates from the central position P1 to one side in the second circumferential direction (+θ2 side), and the driven gear 36 rotates to the other side in the third circumferential direction (-θ3 side). In this case, as shown in Figure 5, the first contact portion 35g moves to one side in the second circumferential direction. Also, the first stopper portion 36f rotates to the other side in the third circumferential direction, that is, toward the second drive gear 35. When the driven gear 36 rotates by a predetermined angle toward the other side in the third circumferential direction, the first stopper portion 36f contacts the first contact portion 35g of the second drive gear 35 from one side in the third circumferential direction, that is, one side in the rotation direction. In other words, the first contact portion 35g is positioned in the rotational movement region of the driven gear 36, that is, the second gear, and is able to contact the first stopper portion 36f. This suppresses the rotation of the driven gear 36 to the other side in the third circumferential direction. Since the rotation of the driven gear 36 is suppressed, the rotation of all gears in the transmission mechanism 30 is suppressed, and thus the output shaft 38 can be prevented from rotating to one side in the third circumferential direction beyond a certain range. At this time, the second drive gear section 35b and the driven gear section 36b remain meshed with each other.

[0066] Next, as shown in Figure 4, we will describe the case where the drive gear 33 rotates from the central position P1 to the other side in the second circumferential direction (-θ2 side), and the driven gear 36 rotates to one side in the third circumferential direction (+θ3 side). In this case, as shown in Figure 6, the second contact portion 35h moves to the other side in the second circumferential direction. Also, the second stopper portion 36g rotates to one side in the third circumferential direction, that is, toward the second drive gear 35. When the driven gear 36 rotates by a predetermined angle toward one side in the third circumferential direction, the second stopper portion 36g contacts the second contact portion 35h of the second drive gear 35 from the other side in the third circumferential direction, that is, the other side in the rotation direction. In other words, the second contact portion 35h is positioned in the rotational movement region of the driven gear 36 and is capable of contacting the second stopper portion 36g. As a result, rotation of the driven gear 36 to one side in the third circumferential direction is suppressed, and rotation of the output shaft 38 to the other side in the third circumferential direction beyond a certain range is suppressed. At this time, the second drive gear section 35b and the driven gear section 36b are maintained in a meshed state with each other.

[0067] According to this embodiment, the gears include a first gear, a drive gear 33, and a second gear, a driven gear 36, which rotates in the rotational direction. The transmission mechanism 30 has a stopper portion 36e and a contact portion 35f positioned in the rotational movement region of the driven gear 36 and capable of contacting the stopper portion 36e. The drive gear 33 has the contact portion 35f, and the driven gear 36 has the stopper portion 36e. Therefore, as described above, when the driven gear 36 rotates by a predetermined angle in the third circumferential direction, i.e., in the rotational direction, the stopper portion 36e of the driven gear 36 and the contact portion 35f of the drive gear 33 come into contact, thereby preventing the driven gear 36 from rotating beyond a predetermined angle. Consequently, the output shaft 38 can be prevented from rotating beyond a certain range. Furthermore, since the driven gear portion 36b of the driven gear 36 and the driven gear portion 33b of the drive gear 33 can be prevented from falling off each other, the electric actuator 1 can be driven stably.

[0068] Furthermore, according to this embodiment, the driven gear 36, which is one of the multiple gears constituting the transmission mechanism 30, has a stopper portion 36e, and the drive gear 33 has a contact portion 35f. Therefore, compared to a configuration in which, for example, another member such as the case 10 has either a stopper portion or a contact portion, it is easier to suppress variations in the relative position of the stopper portion 36e and the contact portion 35f. Consequently, the accuracy of the position in which the driven gear 36 stops rotating can be improved, and therefore the accuracy of the position in which the output shaft 38 stops rotating can be improved. In addition, since the driven gear 36 can be stopped at a desired position, it is possible to suppress the driving gear portion 36b of the driven gear 36 and the drive gear portion 33b of the drive gear 33 from falling off each other.

[0069] In this embodiment, since each of the multiple gears of the transmission mechanism 30 is made of metal, even if a large force is applied to the gear portion of each of the multiple gears when stopping the rotation of the driven gear 36, damage to the gear portion of each of the multiple gears can be suppressed.

[0070] In this embodiment, since the transmission mechanism 30 has both a stopper portion and a contact portion, damage to the case 10 can be suppressed compared to a configuration in which the case 10, which is made of a material with a smaller Young's modulus than the multiple gears of the transmission mechanism 30, has either a stopper portion or a contact portion, and the case 10 suppresses the rotation of at least one of the multiple gears of the transmission mechanism 30.

[0071] According to this embodiment, the stopper portion 36e has a first stopper portion 36f and a second stopper portion 36g, and the contact portion 35f has a first contact portion 35g and a second contact portion 35h, and the first stopper portion 36f can contact the first contact portion 35g from one side in the third circumferential direction, i.e., the rotation direction, and the second stopper portion 36g can contact the second contact portion 35h from the other side (-θ3 side) in the third circumferential direction. Therefore, when the driven gear 36 rotates to the other side in the third circumferential direction, when the driven gear 36 rotates by a predetermined angle, the first stopper portion 36f contacts the first contact portion 35g, thereby preventing the driven gear 36 from rotating beyond the predetermined angle. Furthermore, when the driven gear 36 rotates to one side (+θ3 side) in the third circumferential direction, the second stopper portion 36g contacts the second contact portion 35h when the driven gear 36 rotates by a predetermined angle, thereby preventing the driven gear 36 from rotating beyond a predetermined angle to one side in the third circumferential direction. Thus, it is possible to prevent the output shaft 38 from rotating beyond a certain range in both the one and the other directions of the third circumferential direction.

[0072] According to this embodiment, the drive gear 33 has a contact portion 35f, and the driven gear 36 has a driven gear portion 36b and a driven gear base portion 36a through which the third axis J3 passes, and a stopper portion 36e. The first stopper portion 36f and the second stopper portion 36g protrude radially from the driven gear base portion 36a with respect to the third axis J3, and are arranged in the circumferential direction with respect to the third axis J3, sandwiching the contact portion 35f. Therefore, whether the driven gear 36 rotates to one side (+θ3 side) of the third circumferential direction or to the other side (-θ3 side) of the third circumferential direction, when the driven gear 36 rotates by a predetermined angle, either the first stopper portion 36f or the second stopper portion 36g contacts the contact portion 35f, thereby preventing the driven gear 36 from rotating beyond the predetermined angle.

[0073] <Second Embodiment> Figure 7 is a side view showing the transmission mechanism 230 of the electric actuator 201 of this embodiment. In the following description, components that are the same as those in the first embodiment described above are denoted by the same reference numerals, and their descriptions are omitted. In the transmission mechanism 230 of this embodiment, the driven gear 236 has a contact portion 236h, and the drive gear 233 has a stopper portion 234h. In this embodiment, the driven gear 236 is a first gear having a contact portion 236h. The drive gear 233 is a second gear having a stopper portion 234h. The rotation direction of the second gear is the second circumferential direction. The other configurations of the electric actuator 201 of this embodiment are the same as the other configurations of the electric actuator 1 of the first embodiment described above. Furthermore, in the transmission mechanism 230 shown in Figure 7, the second circumferential center position of the second drive gear section 35b and the third circumferential center position of the driven gear section 36b coincide with the virtual straight line L1 when viewed in the Z-axis direction. In other words, the position of each gear in the transmission mechanism 230 shown in Figure 7 is the central position P1.

[0074] The contact portion 236h is a part of the outer surface of the driven gear base 36a of the driven gear 236. More specifically, the contact portion 236h is a part of the outer surface of the driven gear base 36a facing the third circumferential direction. At the central position P1, the contact portion 236h is located behind the third axis J3 (-Y side) and in front of the driven gear portion 36b (+Y side). Viewed in the Z-axis direction, the contact portion 236h overlaps with the drive gear base 34a. In this embodiment, the contact portion 236h has a first contact portion 236i and a second contact portion 236j.

[0075] The first contact portion 236i is a part of the outer surface of the driven gear base 36a facing the other side (-θ3 side) in the third circumferential direction. At the central position P1, the first contact portion 236i is located to the right (-X side) of the virtual straight line L1. The second contact portion 236j is a part of the outer surface of the driven gear base 36a facing one side (+θ3 side) in the third circumferential direction. At the central position P1, the second contact portion 236j is located to the left (+X side) of the virtual straight line L1.

[0076] In this embodiment, the first drive gear 234 of the drive gear 233 has a drive gear base 34a and a stopper portion 234h. The configuration of the drive gear base 34a is the same as that of the drive gear base 34a in the first embodiment. The stopper portion 234h is provided on the drive gear base 34a. The stopper portion 234h protrudes upward from the second circumferential edge of the upper (+Z) side of the surface of the drive gear base 34a. Viewed in the Z-axis direction, the stopper portion 234h is substantially rectangular in shape. In the Z-axis direction, the upper end of the stopper portion 234h is located above the lower (-Z) side of the surface of the driven gear base 36a. The second radially outer end of the stopper portion 234h is located second radially outward from the second radially outer end of the first drive tooth portion 34c. The stopper portion 234h includes a first stopper portion 234i and a second stopper portion 234j.

[0077] The first stopper portion 234i protrudes upward from the edge of one side (+θ2 side) in the second circumferential direction of the upper side (+Z side) of the surface of the drive gear base portion 34a. At the central position P1, the first stopper portion 234i is positioned to the right (-X side) of the second drive gear 35. At the central position P1, the first stopper portion 234i is positioned on one side in the second circumferential direction of the driven gear 236. At the central position P1, the first stopper portion 234i is positioned on one side in the second circumferential direction of the first contact portion 236i.

[0078] The second stopper portion 234j protrudes upward from the edge on the other side (-θ2 side) in the second circumferential direction of the surface of the drive gear base portion 34a facing the upper side (+Z side). At the central position P1, the second stopper portion 234j is positioned to the left (+X side) of the second drive gear 35. At the central position P1, the second stopper portion 234j is positioned on the other side in the second circumferential direction of the driven gear 236. At the central position P1, the second stopper portion 234j is positioned on the other side in the second circumferential direction of the second contact portion 236j. As a result, the first stopper portion 234i and the second stopper portion 234j are positioned with the contact portion 236h in between in the second circumferential direction.

[0079] Next, a configuration in the electric actuator 201 of this embodiment that suppresses the rotation of the output shaft 38 beyond a certain range will be described. First, let's describe the case where the drive gear 233 rotates from the central position P1 to the other side of the second circumferential direction (-θ2 side), and the driven gear 236 rotates to one side of the third circumferential direction (+θ3 side). In this case, the first contact portion 236i moves to one side of the third circumferential direction. Also, the first stopper portion 234i rotates toward the driven gear 236. When the drive gear 233 rotates by a predetermined angle to the other side of the second circumferential direction, the first stopper portion 234i contacts the first contact portion 236i from one side of the second circumferential direction, i.e., one side in the direction of rotation. As a result, the rotation of the drive gear 233 toward the other side of the second circumferential direction is suppressed, and the rotation of the output shaft 38 beyond a certain range toward one side of the third circumferential direction is suppressed. At this time, the second drive gear portion 35b and the driven gear portion 36b remain meshed with each other.

[0080] Next, we will describe the case where the drive gear 233 rotates from the central position P1 to one side in the second circumferential direction (+θ2 side), and the driven gear 236 rotates to the other side in the third circumferential direction (-θ3 side). In this case, the second contact portion 236j moves to the other side in the third circumferential direction. Also, the second stopper portion 234j rotates toward the driven gear 236. When the drive gear 233 rotates by a predetermined angle to one side in the second circumferential direction, the second stopper portion 234j contacts the second contact portion 236j from the other side in the second circumferential direction, i.e., the other side in the rotation direction. As a result, the rotation of the drive gear 233 to one side in the second circumferential direction is suppressed, and the rotation of the output shaft 38 beyond a certain range to the other side in the third circumferential direction is suppressed. At this time, the second drive gear portion 35b and the driven gear portion 36b remain meshed with each other.

[0081] According to this embodiment, the drive gear 233 has a drive gear base 34a through which the second axis J2 passes, and a stopper portion 234h. The first stopper portion 234i and the second stopper portion 234j are provided on the drive gear base 34a, and the driven gear 236 has a contact portion 236h. The first stopper portion 234i and the second stopper portion 234j are arranged in the circumferential direction centered on the second axis J2, with the contact portion 236h in between. Therefore, whether the drive gear 233 rotates to one side (+θ2 side) of the second circumferential direction or to the other side (-θ2 side) of the second circumferential direction, when the drive gear 233 rotates by a predetermined angle, either the first stopper portion 234i or the second stopper portion 234j will contact the contact portion 236h, thereby preventing the drive gear 233 from rotating beyond the predetermined angle. Therefore, it is possible to suppress the output shaft 38 from rotating beyond a certain range. Furthermore, since it is possible to suppress the second drive gear portion 35b of the drive gear 233 and the driven gear portion 36b of the driven gear 236 from falling off each other, the electric actuator 201 can be driven stably.

[0082] Furthermore, according to this embodiment, since the transmission mechanism 230 has a stopper portion 234h and a contact portion 236h, variations in the relative position of the stopper portion 234h and the contact portion 236h can be suppressed. Therefore, the accuracy of the position where the drive gear 233, i.e., the second gear, stops rotating can be improved, and the accuracy of the position where the output shaft 38 stops rotating can be improved.

[0083] <Third Embodiment> Figure 8 is a side view showing the transmission mechanism 330 of the electric actuator 301 of this embodiment. In the following description, components that are the same as those in the first embodiment described above are denoted by the same reference numerals, and their descriptions are omitted. In the transmission mechanism 330 of this embodiment, the driven gear 336 has a contact portion 336h, and the drive input gear 331 has a stopper portion 331e. In this embodiment, the drive input gear 331 is a first gear having a stopper portion 331e. The driven gear 336 is a second gear having a contact portion 336h. The rotation direction of the second gear is the third circumferential direction. The other configurations of the electric actuator 301 of this embodiment are the same as the other configurations of the electric actuator 1 of the first embodiment described above. Furthermore, in the transmission mechanism 330 shown in Figure 8, the second circumferential center position of the second drive gear section 35b and the third circumferential center position of the driven gear section 36b coincide with the virtual straight line L1 when viewed in the Z-axis direction. In other words, the position of each gear in the transmission mechanism 330 shown in Figure 8 is the central position P1.

[0084] The contact portion 336h is a part of the outer surface of the driven gear base 36a of the driven gear 336. More specifically, the contact portion 336h is a part of the outer surface of the driven gear base 36a facing the third circumferential direction. At the central position P1, the contact portion 336h is located behind (-Y side of) the third axis J3. Viewed in the Z-axis direction, the contact portion 336h overlaps with the drive input gear 331. In this embodiment, the contact portion 336h has a first contact portion 336i and a second contact portion 336j.

[0085] The first contact portion 336i is a part of the outer surface of the driven gear base 36a facing one side (+θ3 side) in the third circumferential direction. At the central position P1, the first contact portion 336i is located to the left (+X side) of the virtual straight line L1. The second contact portion 336j is a part of the outer surface of the driven gear base 36a facing the other side (-θ3 side) in the third circumferential direction. At the central position P1, the second contact portion 336j is located to the right (-X side) of the virtual straight line L1.

[0086] The stopper portion 331e is fixed to the drive input main body portion 31a. The stopper portion 331e protrudes radially outward from the drive input main body portion 31a. The stopper portion 331e is a substantially annular member centered on the motor shaft J1. In this embodiment, the stopper portion 331e is an E-type retaining ring. The stopper portion 331e is fixed to a groove (not shown) provided on the outer circumferential surface of the drive input main body portion 31a. Therefore, according to this embodiment, the stopper portion 331e can be easily fixed to the drive input main body portion 31a, thereby suppressing an increase in the manufacturing man-hours of the electric actuator 301. Note that the stopper portion 331e may be other members such as a C-type retaining ring. The stopper portion 331e has a first stopper portion 331f and a second stopper portion 234j.

[0087] The first stopper portion 331f is fixed to the body portion 31b of the drive input main body portion 31a. More specifically, it is fixed to a groove (not shown) provided on the outer circumferential surface of the left side (+X side) portion of the body portion 31b. The first stopper portion 331f is positioned on one side (+θ3 side) in the third circumferential direction of the driven gear 336. The first stopper portion 331f is positioned on one side in the third circumferential direction of the first contact portion 336i. The upper side (+Z side) portion of the first stopper portion 331f faces the first contact portion 336i in the third circumferential direction.

[0088] The second stopper portion 331g is fixed to the connection portion 31c of the drive input body portion 31a. More specifically, it is fixed to a groove (not shown) provided on the outer circumferential surface of the connection portion 31c. The second stopper portion 331g is positioned on the other side (-θ3 side) of the third circumferential direction from the driven gear 336. The second stopper portion 331g is positioned on the other side of the second contact portion 336j in the third circumferential direction. The upper (+X side) portion of the second stopper portion 331g faces the second contact portion 336j in the third circumferential direction. As a result, the first stopper portion 234i and the second stopper portion 234j are positioned so that the contact portion 336h is sandwiched between them in the axial direction, i.e., in the direction in which the motor shaft J1 extends.

[0089] Next, a configuration in the electric actuator 301 of this embodiment that suppresses the rotation of the output shaft 38 beyond a certain range will be described. First, let's describe the case where the drive input gear 331 rotates to one side in the circumferential direction (+θ1 side) from the central position P1, and the driven gear 336 rotates to one side in the third circumferential direction (+θ3 side). In this case, the first contact portion 336i moves to one side in the third circumferential direction. When the driven gear 336 rotates by a predetermined angle to one side in the third circumferential direction, the first stopper portion 331f contacts the first contact portion 336i from one side in the third circumferential direction, i.e., one side in the rotation direction. As a result, the rotation of the driven gear 336 to one side in the third circumferential direction is suppressed, and the rotation of the output shaft 38 beyond a certain range to one side in the third circumferential direction is suppressed.

[0090] Next, we will describe the case where the drive input gear 331 rotates from the central position P1 to the other side in the circumferential direction (-θ1 side), and the driven gear 336 rotates to the other side in the third circumferential direction (-θ3 side). In this case, the second contact portion 336j moves to the other side in the third circumferential direction. When the driven gear 336 rotates by a predetermined angle to the other side in the third circumferential direction, the second stopper portion 331g contacts the second contact portion 336j from the other side in the third circumferential direction, i.e., the other side in the rotation direction. As a result, the rotation of the driven gear 336 to the other side in the third circumferential direction is suppressed, and the rotation of the output shaft 38 beyond a certain range to the other side in the third circumferential direction is suppressed.

[0091] Therefore, according to this embodiment, whether the driven gear 336 rotates to one side (+θ3 side) in the third circumferential direction or to the other side (-θ3 side) in the third circumferential direction, when the driven gear 336 rotates by a predetermined angle, either the first stopper portion 331f or the second stopper portion 331g comes into contact with the contact portion 336h, thereby preventing the driven gear 336 from rotating beyond the predetermined angle. Consequently, the output shaft 38 can be prevented from rotating beyond a certain range.

[0092] Furthermore, according to this embodiment, since the transmission mechanism 330 has a stopper portion 331e and a contact portion 336h, variations in the relative position of the stopper portion 331e and the contact portion 336h can be suppressed. Therefore, the accuracy of the position where the driven gear 336, i.e., the second gear, stops rotating can be improved, and the accuracy of the position where the output shaft 38 stops rotating can be improved.

[0093] Although embodiments of the present invention have been described above, the configurations and combinations thereof in the embodiments are merely examples, and additions, omissions, substitutions, and other modifications are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited by the embodiments.

[0094] For example, the electric actuator to which the present invention is applied may be any device that can move an object when power is supplied to it, and may be a motor without a transmission mechanism. Alternatively, the electric actuator may be an electric pump comprising a pump section driven by a motor section. The application of the electric actuator is not particularly limited and may be mounted on equipment other than vehicles. Furthermore, the configurations described herein can be combined as appropriate, within the bounds of mutual non-inconsistency.

[0095] Furthermore, the configuration of the transmission mechanism is not limited to the above-described embodiment, as long as the transmission mechanism has a stopper portion and a contact portion that can prevent the output shaft from rotating beyond a predetermined range. For example, the number of gears in the transmission mechanism may be two or fewer, or four or more. The transmission mechanism may have two or more stopper portions and two or more contact portions. Also, the shape of the drive gear and the driven gear does not have to be a fan shape; they may be other shapes such as a circular shape.

[0096] Furthermore, this technology can be configured as follows: (1) An electric actuator comprising: a motor section having a rotor rotatable about a motor shaft; and a transmission mechanism having a plurality of gears that rotate when the rotation of the rotor is transmitted, wherein the plurality of gears include a first gear and a second gear that rotates in the rotational direction; the transmission mechanism having a stopper section and a contact section arranged in the rotational movement region of the second gear and capable of contacting the stopper section; the first gear having one of the stopper section and the contact section; and the second gear having the other of the stopper section and the contact section. (2) The electric actuator according to (1), wherein the stopper portion comprises a first stopper portion and a second stopper portion, the contact portion comprises a first contact portion and a second contact portion, the first stopper portion is capable of contacting the first contact portion from one side in the rotational direction, and the second stopper portion is capable of contacting the second contact portion from the other side in the rotational direction. (3) The electric actuator according to (2), wherein the first gear is a drive gear rotatable about a second axis, the drive gear has a drive gear portion extending in an arc shape along the circumferential direction about the second axis, and the second gear is a driven gear rotatable about a third axis extending in the direction in which the second axis extends, the driven gear has a driven gear portion extending in an arc shape along the circumferential direction about the third axis and meshing with the drive gear portion. (4) The electric actuator according to (3), wherein the drive gear has the contact portion, the driven gear has the driven gear portion and a driven gear base through which the third axis passes, and the stopper portion, the first stopper portion and the second stopper portion protrude radially from the driven gear base with respect to the third axis and are arranged in a circumferential direction with respect to the third axis, sandwiching the contact portion. (4) The electric actuator according to (3), wherein the drive gear has a drive gear base through which the second axis passes and a stopper portion, the first stopper portion and the second stopper portion are provided on the drive gear base, the driven gear has the contact portion, and the first stopper portion and the second stopper portion are arranged in a circumferential direction with respect to the second axis, with the contact portion in between. (6) The electric actuator according to (2), wherein the first gear is a drive input gear having a drive input gear portion and rotatable together with the rotor about the motor shaft, the second gear is a driven gear having a driven gear portion, the plurality of gears include drive gears having a first drive gear portion and a second drive gear portion, the drive input gear portion and the first drive gear portion mesh with each other, the second drive gear portion and the driven gear portion mesh with each other, the driven gear has the contact portion, and the drive input gear has the stopper portion. (7) The electric actuator according to (6), wherein the drive input gear has a drive input body portion extending along the motor shaft, the drive input gear portion is provided on the outer circumferential surface of the drive input body portion and is rotatable about the motor shaft, the driven gear is rotatable about a third axis intersecting the motor shaft, and the first stopper portion and the second stopper portion are arranged so as to sandwich the contact portion in the direction in which the motor shaft extends. (7) The electric actuator according to (7), wherein the first stopper portion and the second stopper portion are each annular members fixed to the drive input body portion and protruding radially outward from the drive input body portion. [Explanation of Symbols]

[0097] 1, 201, 301…Electric actuator, 10…Case, 20…Motor section, 22…Rotor, 30, 230, 330…Transmission mechanism, 31a…Drive input main body, 31d…Drive input gear section, 33, 233…Drive gear, 33, 236, 331…First gear, 33b…Drive gear section, 34a…Drive gear base, 34b…First drive gear section, 35b…Second drive gear section, 35f, 236h, 336h…Contact section, 35g, 236i, 3 36i…First contact part, 35h, 236j, 336j…Second contact part, 36, 236, 336…Driven gear, 36, 233, 336…Second gear, 36a…Driven gear base, 36b…Driven gear part, 36e, 234h, 331e…Stopper part, 36f, 234i, 331f…First stopper part, 36g, 234j, 331g…Second stopper part, 331…Drive input gear, J1…Motor shaft, J2…Second axis, J3…Third axis

Claims

1. A motor unit having a rotor that can rotate around the motor shaft, A transmission mechanism having a plurality of gears that rotate when the rotation of the rotor is transmitted, Equipped with, The plurality of gears include a first gear and a second gear that rotates in the rotational direction, The aforementioned transmission mechanism is The stopper part, A contact portion is arranged in the rotational movement region of the second gear and is capable of contacting the stopper portion, It has, The first gear is a drive input gear having a drive input gear section and rotatable together with the rotor around the motor shaft, The second gear is a driven gear having a driven gear portion, The plurality of gears include a drive gear having a first drive gear section and a second drive gear section, The drive input gear section and the first drive gear section mesh with each other. The second drive gear and the driven gear mesh with each other. The driven gear has the contact portion, The drive input gear is an electric actuator having the stopper portion.

2. The stopper portion comprises a first stopper portion and a second stopper portion. The contact portion has a first contact portion and a second contact portion. The first stopper portion is capable of contacting the first contact portion from one side in the rotational direction, The electric actuator according to claim 1, wherein the second stopper portion is capable of contacting the second contact portion from the other side in the rotational direction.

3. The drive input gear has a drive input body portion that extends along the motor shaft, The drive input gear section is provided on the outer circumferential surface of the drive input main body and is rotatable about the motor shaft. The driven gear is rotatable about a third axis that intersects the motor shaft. The electric actuator according to claim 2, wherein the first stopper portion and the second stopper portion are arranged to sandwich the contact portion in the direction in which the motor shaft extends.

4. The electric actuator according to claim 3, wherein the first stopper portion and the second stopper portion are each annular members fixed to the drive input body portion and protruding radially outward from the drive input body portion.

Images