Electric actuator and method for manufacturing electric actuator

Abstract

To provide an electric actuator having a structure with which it is possible to improve the strength of fixation of an internal gear to a case.SOLUTION: The electric actuator comprises: a motor having a motor shaft capable of rotating around a center axis extending in an axial direction; a speed reduction mechanism having an external gear connected to the motor shaft and an annular internal gear 32 surrounding the radial outside of the external gear; a case for accommodating the motor and the speed reduction mechanism in the inside; and a fixing member 180 for fixing the internal gear to the case. The case includes: a bottom wall part 13j that supports the internal gear from one side in the axial direction; and a peripheral wall part 13k positioned on the radial outside of the internal gear and surrounding the internal gear. The fixing member includes an annular part 181 that surrounds the internal gear between the internal gear and the peripheral wall part in a radial direction. The annular part is in contact with an outer circumferential surface of the internal gear and an inner circumferential surface of the peripheral wall part. A hardness of a material constituting the fixing member is smaller than a hardness of a material constituting the internal gear and a hardness of a material constituting the peripheral wall part.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an electric actuator and a method for manufacturing an electric actuator. [Background technology]

[0002] There is known an electric actuator equipped with a reduction gear. For example, Patent Document 1 describes a reduction gear having a sun gear provided on the outer periphery of an eccentric part of an input shaft via a bearing, and a ring gear that meshes with the sun gear. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-109226 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described reducer, for example, the ring gear is fixed by being press-fitted into the case. However, simply pressing the ring gear may cause problems such as the ring gear coming out of the case or the ring gear being misaligned with respect to the case.

[0005] In view of the above circumstances, an object of the present invention is to provide an electric actuator having a structure capable of improving the fixing strength of the internal gear to the case. Another object of the present invention is to provide a manufacturing method for an electric actuator capable of improving the fixing strength of the internal gear to the case. [Means for solving the problem]

[0006] One embodiment of the electric actuator of the present invention is a rotary actuator having a central axis extending in the axial direction. a motor having a motor shaft that can be rotated; an external gear connected to the motor shaft; a reduction mechanism having an annular internal gear surrounding the radial outside of the external gear; a case for accommodating the reduction mechanism therein; and a fixing portion for fixing the internal gear to the case. The case includes a bottom wall portion that supports the internal gear from one axial side, and a front a peripheral wall portion located radially outward of the internal gear and surrounding the internal gear. The material has an annular portion surrounding the internal gear between the internal gear and the peripheral wall portion in the radial direction. The annular portion is in contact with an outer circumferential surface of the internal gear and an inner circumferential surface of the peripheral wall portion. The hardness of the material constituting the fixing member is lower than the hardness of the material constituting the internal gear and the hardness of the material constituting the peripheral wall portion. a first recess recessed radially outwardly on an inner circumferential surface of the peripheral wall portion, the fixing member having an insertion portion inserted into the first recess, the insertion portion being in contact with an inner surface of the first recess. Electric actuator. Moreover, one aspect of the electric actuator of the present invention is an electric actuator comprising: a motor having a motor shaft rotatable around a central axis extending in the axial direction; a reduction mechanism having an external gear connected to the motor shaft and an annular internal gear surrounding the radial outside of the external gear; a case that houses the motor and the reduction mechanism; and a fixing member that fixes the internal gear to the case, wherein the case has a bottom wall portion that supports the internal gear from one axial side, and a peripheral wall portion that is located radially outside the internal gear and surrounds the internal gear, the fixing member has an annular portion that surrounds the internal gear radially between the internal gear and the peripheral wall portion, the annular portion contacts an outer peripheral surface of the internal gear and an inner peripheral surface of the peripheral wall portion, the hardness of the material constituting the fixing member is smaller than the hardness of the material constituting the internal gear and the hardness of the material constituting the peripheral wall portion, the internal gear has a second recess on its outer peripheral surface, and the fixing member has a protrusion that is located inside the second recess. Furthermore, one aspect of the electric actuator of the present invention includes a motor having a motor shaft rotatable about a central axis extending in the axial direction, a reduction mechanism having an external gear connected to the motor shaft and an annular internal gear surrounding the radial outside of the external gear, a case that houses the motor and the reduction mechanism, and a fixing member that fixes the internal gear to the case, the case having a bottom wall portion that supports the internal gear from one axial side, an annular portion surrounding the internal gear and located radially outside the internal gear, the fixed member having an annular portion surrounding the internal gear radially between the internal gear and the circumferential wall portion, the annular portion contacting an outer circumferential surface of the internal gear and an inner circumferential surface of the circumferential wall portion, the hardness of a material constituting the fixed member being less than a hardness of a material constituting the internal gear and a hardness of a material constituting the circumferential wall portion, the inner circumferential surface of the circumferential wall portion having a first recess recessed radially outward, a portion of the fixed member contacting an inner surface of the first recess, the internal gear having a second recess on its outer circumferential surface, and a portion of the fixed member located inside the second recess.

[0007] In one embodiment of the method for manufacturing an electric actuator of the present invention, a motor having a rotatable motor shaft as a rotor; and an external device connected to the motor shaft. a reduction mechanism having a toothed gear and an annular internal gear surrounding the radially outer side of the external gear; A case for accommodating a motor and the reduction mechanism therein is provided for manufacturing an electric actuator. The manufacturing method includes fixing the internal gear to the case using a fixing member having an annular portion. The case includes a bottom wall portion that supports the internal gear from one axial side, and a front wall portion that supports the internal gear from one axial side. a peripheral wall portion located radially outward of the internal gear and surrounding the internal gear, The hardness of the internal gear is smaller than the hardness of the peripheral wall portion, and the fixing step includes: The fixing member in a state in which the annular portion is disposed between the internal gear and the peripheral wall portion in the radial direction. a deformation process of pressing the bottom wall portion from the other axial side toward the one axial side to deform the bottom wall portion; In the deformation process, the annular portion is deformed and pressed against an outer circumferential surface of the internal gear and an inner circumferential surface of the peripheral wall portion. a first recess portion recessed radially outwardly on an inner circumferential surface of the peripheral wall portion, and in the deformation process, a part of the fixing member is deformed and enters into the first recess portion; A manufacturing method for an electric actuator. Effect of the Invention

[0008] According to one aspect of the present invention, in an electric actuator, the fixing strength of an internal gear to a case can be improved. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing an electric actuator according to one embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing a part of the electric actuator of the embodiment, taken along line II-II in FIG. [Diagram 3] FIG. 3 is a cross-sectional view showing a part of a case, a part of an internal gear, and a part of a fixing member in one embodiment. [Figure 4] FIG. 4 is a perspective view showing a fixing member according to one embodiment. [Diagram 5] FIG. 5 is a flow chart showing an example of the procedure of the fixing step according to one embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing a part of the procedure of the fixing step according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In each figure, the Z-axis direction is the up-down direction with the side toward which the arrow points (+Z side) being the top and the opposite side to the side toward which the arrow points (-Z side) being the bottom. The axial direction of the central axis J1 shown appropriately in each figure is parallel to the Z-axis direction, i.e., the up-down direction. In the following description, unless otherwise specified, the direction parallel to the axial direction of the central axis J1 will simply be referred to as the "axial direction." Furthermore, unless otherwise specified, the radial direction centered on the central axis J1 will simply be referred to as the "radial direction," and the circumferential direction centered on the central axis J1 will simply be referred to as the "circumferential direction."

[0011] In this embodiment, the upper side corresponds to the other axial side, and the lower side corresponds to one axial side. Note that the terms "upper side" and "lower side" are merely names used to describe the relative positional relationship of each part, and the actual positional relationship may be a relationship other than the positional relationship indicated by these names.

[0012] 1 and 2, the electric actuator 10 of this embodiment is, for example, an electric actuator mounted on a vehicle. As shown in Fig. 1, the electric actuator 10 includes a case 11, a motor 20 having a motor shaft 21 rotatable about a central axis J1 extending in the axial direction, a first bearing 51, a second bearing 52, a third bearing 53, a bush 54, a reduction gear mechanism 30, an output unit 40, a preload member 60, a circuit board 70, a first rotation sensor 71, an attachment member 72, a first sensor magnet 73, a second sensor magnet 74, a second rotation sensor (not shown), and a fixing member 80.

[0013] The case 11 accommodates the motor 20 and the reduction mechanism 30 therein. The case 11 has a motor case 12 that accommodates the motor 20 therein, and a reduction mechanism case 13 that accommodates the reduction mechanism 30 therein. In this embodiment, the motor case 12 and the reduction mechanism case 13 are each made by die casting. The material constituting the motor case 12 and the material constituting the reduction mechanism case 13 are, for example, an alloy containing aluminum. The motor case 12 has a case cylinder portion 12a, an annular plate portion 12b, an upper cover portion 12c, a bearing holding portion 12d, and a circuit board accommodating portion 12g.

[0014] The case tube portion 12a is cylindrical and extends in the axial direction around the central axis J1. The case tube portion 12a is open on both sides in the axial direction. The case tube portion 12a surrounds the radial outside of the motor 20. The annular plate portion 12b is annular and extends radially inward from the inner peripheral surface of the case tube portion 12a. The annular plate portion 12b covers the upper side of a stator 23 of the motor 20, which will be described later. The radial inner edge portion of the annular plate portion 12b is curved downward.

[0015] The bearing holder 12d is provided on the radial inner edge of the annular plate portion 12b. The bearing holder 12d holds the third bearing 53. The bearing holder 12d has a holder body 12e and a support wall portion 12f. The holder body 12e is cylindrical and extends upward from the radial inner edge of the annular plate portion 12b. The support wall portion 12f protrudes radially inward from the upper end of the holder body 12e. Although not shown, the support wall portion 12f is annular and extends circumferentially.

[0016] The circuit board accommodating portion 12g is a portion that accommodates the circuit board 70. The circuit board accommodating portion 12g is configured radially inward of the upper portion of the case cylindrical portion 12a. The bottom surface of the circuit board accommodating portion 12g is the upper surface of the annular plate portion 12b. The circuit board accommodating portion 12g opens upward. The upper cover portion 12c is a plate-shaped cover that closes the upper end opening of the circuit board accommodating portion 12g.

[0017] The reduction gear case 13 is fixed to the lower side of the motor case 12. The reduction gear case 13 has a lid portion 13a, a cylindrical portion 13b, and a protruding cylindrical portion 13c. The lid portion 13a is in the shape of an annular plate centered on the central axis J1. The lid portion 13a covers the lower side of the reduction gear mechanism 30.

[0018] The tubular portion 13b is cylindrical and protrudes upward from the radial outer edge of the lid portion 13a. The tubular portion 13b is open at the top. The upper end of the tubular portion 13b is fixed in contact with the lower end of the case tubular portion 12a. The tubular portion 13b has a bottom wall portion 13j and a peripheral wall portion 13k. In other words, the case 11 has the bottom wall portion 13j and the peripheral wall portion 13k.

[0019] In this embodiment, the bottom wall portion 13j is an upper end portion of the radially inner portion of the cylindrical portion 13b. The bottom wall portion 13j is annular about the central axis J1. The bottom wall portion 13j supports the internal gear 32, which will be described later, from below. As shown in FIG. 3, the bottom wall portion 13j has an annular step portion 13g surrounding the central axis J1 on its upper surface. In this embodiment, the step portion 13g is annular about the central axis J1. The step portion 13g is a step that is recessed downward when tracing the upper surface of the bottom wall portion 13j from the radially outer side to the radially inner side. In other words, the inner bottom surface portion 13i located radially inner than the step portion 13g on the upper surface of the bottom wall portion 13j is located lower than the outer bottom surface portion 13m located radially outer than the step portion 13g on the upper surface of the bottom wall portion 13j. The inner bottom surface portion 13i and the outer bottom surface portion 13m are flat surfaces that face upward and are perpendicular to the axial direction. The step portion 13g is located in the radial center of the upper surface of the bottom wall portion 13j.

[0020] As shown in FIG. 1, the peripheral wall portion 13k protrudes upward from the radial outer peripheral edge portion of the bottom wall portion 13j. The peripheral wall portion 13k is annular about the central axis J1. The peripheral wall portion 13k is located radially outside the internal gear 32 described later and surrounds the internal gear 32. As shown in FIG. 3, in this embodiment, the inner peripheral surface of the peripheral wall portion 13k is provided with a first recessed portion 13f recessed radially outward. The first recessed portion 13f is provided at the lower end of the inner peripheral surface of the peripheral wall portion 13k. As shown in FIG. 2, in this embodiment, the first recessed portion 13f is annular about the internal gear 32. More specifically, the first recessed portion 13f is annular about the central axis J1. As shown in FIG. 3, the axial dimension of the first recessed portion 13f decreases toward the radially outward direction.

[0021] In this embodiment, the cross-sectional shape of the first recess 13f perpendicular to the circumferential direction is a triangle having an acute apex on the radially outer side. The surface located on the lower side of the inner side of the first recess 13f is a flat surface perpendicular to the axial direction and is connected to the radially outer side of the outer bottom surface portion 13m without any steps. The surface located on the upper side of the inner side of the first recess 13f is a tapered surface that is positioned downward as it goes radially outward.

[0022] 1, a recess 13e is formed at the radially inner portion of the upper end of the cylindrical portion 13b by a bottom wall portion 13j and a peripheral wall portion 13k. The recess 13e is open to the radially inner side. The recess 13e is annular and has a center on the central axis J1.

[0023] The protruding tubular portion 13c is cylindrical and protrudes from the radial inner edge of the cover portion 13a on both axial sides. The protruding tubular portion 13c is open on both axial sides. The upper end of the protruding tubular portion 13c is located lower than the upper end of the tubular portion 13b. An O-ring 61 is attached to the outer circumferential surface at the lower end of the protruding tubular portion 13c. A cylindrical bush 54 extending in the axial direction is disposed inside the protruding tubular portion 13c.

[0024] The motor 20 is housed in a portion of the case 11 below the annular plate portion 12b. The motor 20 includes a rotor 22 and a stator 23. The rotor 22 includes a motor shaft 21 and a rotor body 22a. The motor shaft 21 is supported by a first bearing 51 and a third bearing 53 so as to be rotatable about a central axis J1. The motor shaft 21 includes a first shaft portion 21a, a second shaft portion 21b, a third shaft portion 21c, a fourth shaft portion 21d, a fifth shaft portion 21e, a sixth shaft portion 21f, a seventh shaft portion 21g, and an eighth shaft portion 21h. Each shaft portion except the sixth shaft portion 21f is centered on the central axis J1.

[0025] The first shaft portion 21a is an upper end portion of the motor shaft 21. The first shaft portion 21a protrudes upward from the annular plate portion 12b through the radial inner side of the bearing holding portion 12d. The first shaft portion 21a is a portion of the motor shaft 21 with the smallest outer diameter. The second shaft portion 21b is connected to the lower side of the first shaft portion 21a. The outer diameter of the second shaft portion 21b is larger than the outer diameter of the first shaft portion 21a. The third shaft portion 21c is connected to the lower side of the second shaft portion 21b. The outer diameter of the third shaft portion 21c is larger than the outer diameter of the second shaft portion 21b. As a result, a step portion 21i whose outer diameter increases from the upper side to the lower side is provided between the second shaft portion 21b and the third shaft portion 21c. That is, the motor shaft 21 has the step portion 21i.

[0026] The fourth shaft portion 21d is connected to the lower side of the third shaft portion 21c. The outer diameter of the fourth shaft portion 21d is larger than the outer diameter of the third shaft portion 21c. A balance weight 24 is fixed to the fourth shaft portion 21d. The balance weight 24 is a plate-like plate with a plate surface facing the axial direction. The fifth shaft portion 21e is connected to the lower side of the fourth shaft portion 21d. The outer diameter of the fifth shaft portion 21e is larger than the outer diameter of the fourth shaft portion 21d. The fifth shaft portion 21e is the part of the motor shaft 21 with the largest outer diameter. The balance weight 24 is in contact with the upper end of the fifth shaft portion 21e. This allows the balance weight 24 to be positioned in the axial direction relative to the motor shaft 21.

[0027] The sixth shaft portion 21f is connected to the lower side of the fifth shaft portion 21e. The sixth shaft portion 21f is an eccentric shaft portion centered on an eccentric shaft J2 that is eccentric with respect to the central axis J1. The eccentric shaft J2 is parallel to the central axis J1 and is located radially outward of the central axis J1. The outer diameter of the sixth shaft portion 21f is smaller than the outer diameter of the fifth shaft portion 21e. That is, the fifth shaft portion 21e is connected to the upper side of the sixth shaft portion 21f and is a large-diameter shaft portion having an outer diameter larger than that of the sixth shaft portion 21f. The outer diameter of the sixth shaft portion 21f is smaller than the outer diameter of the fourth shaft portion 21d and larger than the outer diameter of the third shaft portion 21c.

[0028] The seventh shaft portion 21g is connected to the lower side of the sixth shaft portion 21f. The outer diameter of the seventh shaft portion 21g is smaller than the outer diameter of the sixth shaft portion 21f. The eighth shaft portion 21h is connected to the lower side of the seventh shaft portion 21g. The eighth shaft portion 21h is the lower end of the motor shaft 21. The outer diameter of the eighth shaft portion 21h is smaller than the outer diameter of the seventh shaft portion 21g. The seventh shaft portion 21g and the eighth shaft portion 21h are accommodated inside the accommodating recess 41a described later.

[0029] The rotor body 22a is fixed to the outer circumferential surface of the motor shaft 21. More specifically, the rotor body 22a is fixed to the outer circumferential surface of the third shaft portion 21c. Although not shown, the rotor body 22a has a rotor core fixed to the outer circumferential surface of the motor shaft 21 and a rotor magnet fixed to the rotor core.

[0030] The stator 23 is located radially outside the rotor 22. The stator 23 has a stator core 23a and a plurality of coils 23b. The stator core 23a is annular and surrounds the radially outside of the rotor 22. The outer circumferential surface of the stator core 23a is fixed to the inner circumferential surface of the case cylindrical portion 12a. The plurality of coils 23b are attached to the stator core 23a, for example, via an insulator (not shown).

[0031] The first bearing 51, the second bearing 52, and the third bearing 53 are each a rolling bearing having an inner ring and an outer ring located radially outward of the inner ring. In this embodiment, the first bearing 51, the second bearing 52, and the third bearing 53 are, for example, ball bearings in which the inner ring and the outer ring are connected via a plurality of balls.

[0032] In this embodiment, the reduction mechanism 30 is disposed radially outside a lower portion of the motor shaft 21. The reduction mechanism 30 is housed inside the reduction mechanism case 13. The reduction mechanism 30 is disposed axially between the cover portion 13a and the motor 20. The reduction mechanism 30 has an external gear 31, an internal gear 32, a flange portion 42, and a plurality of protrusions 43.

[0033] As shown in FIG. 2, the external gear 31 is annular and surrounds the sixth shaft portion 21f, which is an eccentric shaft portion, on the radial outside of the sixth shaft portion 21f. More specifically, the external gear 31 is substantially annular and extends on a plane perpendicular to the axial direction, with the eccentric shaft J2 as the center. A gear portion having a plurality of teeth 31d is provided on the radially outer side surface of the external gear 31. The external gear 31 is connected to the sixth shaft portion 21f via a second bearing 52. As a result, the reduction mechanism 30 is connected to a lower portion of the motor shaft 21. The second bearing 52 connects the motor shaft 21 and the external gear 31 so as to be rotatable relative to each other around the eccentric shaft J2. The external gear 31 is fitted into the outer ring of the second bearing 52 from the radially outer side.

[0034] As shown in FIG. 1, the external gear 31 has an external gear body 31a and a contact protrusion 31b. The external gear body 31a is a substantially annular plate-shaped portion fixed to the outer ring of the second bearing 52. The contact protrusion 31b is a portion protruding downward from the external gear body 31a. In this embodiment, the contact protrusion 31b protrudes downward from the radial inner edge of the external gear body 31a. Although not shown, the contact protrusion 31b is annular about the eccentric axis J2. The lower surface of the contact protrusion 31b is a flat surface perpendicular to the axial direction. The lower surface of the contact protrusion 31b is a machined surface made by, for example, cutting.

[0035] The external gear 31 has a plurality of holes 31c recessed upward. The plurality of holes 31c are provided in the external gear body 31a. In this embodiment, the holes 31c penetrate the external gear 31 in the axial direction. As shown in FIG. 2, the plurality of holes 31c are arranged along the circumferential direction. More specifically, the plurality of holes 31c are arranged at equal intervals around one circumference along the circumferential direction centered on the eccentric axis J2. The holes 31c are, for example, circular when viewed in the axial direction. The inner diameter of the holes 31c is larger than the outer diameter of the protrusion 43. The number of holes 31c is, for example, eight.

[0036] The internal gear 32 is annular and surrounds the radial outside of the external gear 31. More specifically, the internal gear 32 is annular and centered on the central axis J1. A gear portion having a plurality of teeth 32d is provided on the inner peripheral surface of the internal gear 32. The gear portion of the internal gear 32 meshes with the gear portion of the external gear 31. More specifically, the gear portion of the internal gear 32 meshes with the gear portion of the external gear 31 at a portion of the circumferential direction. As a result, the internal gear 32 meshes with the external gear 31.

[0037] As shown in FIG. 3, the internal gear 32 is located radially inside the peripheral wall portion 13k. The internal gear 32 is disposed on the upper surface of the bottom wall portion 13j. The upper surface 32e of the internal gear 32 is a flat surface perpendicular to the axial direction. The upper surface 32e of the internal gear 32 is located lower than the upper surface 13h of the peripheral wall portion 13k. The material constituting the internal gear 32 is metal. The metal constituting the internal gear 32 is, for example, iron. The internal gear 32 has an internal gear main body 32a and an annular protrusion 32b. The internal gear main body 32a is an annular portion having a gear portion provided on its inner peripheral surface. The lower surface of the radially outer portion of the internal gear main body 32a is in contact with the outer bottom surface portion 13m.

[0038] The annular protrusion 32b protrudes downward from the internal gear body 32a. More specifically, the annular protrusion 32b protrudes downward from a radially inner portion of the internal gear body 32a. The annular protrusion 32b is annular about the central axis J1. The annular protrusion 32b is fitted into the radially inner side of the step portion 13g. The lower surface of the annular protrusion 32b is a flat surface perpendicular to the axial direction. The lower surface of the annular protrusion 32b is in contact with the inner bottom surface portion 13i. The radial inner edge of the annular protrusion 32b is located at the same position in the radial direction as the radial inner edge of the internal gear body 32a.

[0039] As shown in FIG. 2, in this embodiment, the internal gear 32 has a second recess 32c on the outer circumferential surface. The second recess 32c is recessed radially inward. The second recess 32c, for example, penetrates the internal gear 32 in the axial direction. The inside of the second recess 32c is rectangular when viewed in the axial direction. In this embodiment, a plurality of second recesses 32c are provided at intervals in the circumferential direction. The plurality of second recesses 32c are provided at equal intervals around one circumference along the circumferential direction. For example, four second recesses 32c are provided.

[0040] The internal gear 32 is fixed to the reduction gear case 13 by the fixing member 80. That is, the fixing member 80 is a member that fixes the internal gear 32 to the case 11. The fixing member 80 is an annular member that surrounds the internal gear 32. More specifically, the fixing member 80 is annular about the central axis J1. The fixing member 80 is located between the internal gear 32 and the peripheral wall portion 13k in the radial direction. The fixing member 80 contacts the internal gear 32 and the peripheral wall portion 13k. The fixing member 80 is axially crushed and deformed while being inserted between the internal gear 32 and the peripheral wall portion 13k, thereby fixing the internal gear 32 to the peripheral wall portion 13k. The fixing member 80 has an annular portion 81, a pressing portion 82, a protruding portion 83, and an inserting portion 84.

[0041] The annular portion 81 is an annular portion surrounding the internal gear 32 between the internal gear 32 and the peripheral wall portion 13k in the radial direction. As shown in FIG. 4, in this embodiment, the annular portion 81 is cylindrical with the central axis J1 as the center and opening on both axial sides. In FIG. 4, the fixing member 180 before being deformed to fix the internal gear 32 is shown by a solid line, and the fixing member 80 after being deformed to fix the internal gear 32 is shown by a two-dot chain line. In reality, the fixing member 180 before being deformed and the fixing member 80 after being deformed have some parts that are different in size from each other, but in FIG. 4, the fixing member 180 before being deformed and the fixing member 80 after being deformed are shown in the same manner for the parts where only the size has changed. The fixing member 180 before being deformed does not have an insertion portion 84.

[0042] 3, the annular portion 81 contacts the outer peripheral surface of the internal gear 32 and the inner peripheral surface of the peripheral wall portion 13k. The inner peripheral surface of the annular portion 81 contacts the outer peripheral surface of the internal gear main body 32a. The outer peripheral surface of the annular portion 81 contacts the inner peripheral surface of the peripheral wall portion 13k. The annular portion 81 applies a force F, for example, in a direction that presses the outer peripheral surface of the internal gear 32 radially inward and in a direction that presses the inner peripheral surface of the peripheral wall portion 13k radially outward.

[0043] The pressing portion 82 protrudes radially inward from the upper end of the annular portion 81. In this embodiment, the radially inner end of the pressing portion 82 is located radially inward from the step portion 13g. The pressing portion 82 contacts the upper surface 32e of the internal gear 32. More specifically, the lower surface of the pressing portion 82 contacts the upper surface 32e of the internal gear 32. As shown in FIG. 4, in this embodiment, the pressing portion 82 is annular about the central axis J1. The pressing portion 82 is plate-shaped with the plate surface facing the axial direction. As shown in FIG. 3, the upper surface 82a of the pressing portion 82 and the upper surface 13h of the peripheral wall portion 13k are disposed at the same position in the axial direction. In this embodiment, the upper surface 82a of the pressing portion 82 is continuously connected to the radially inner side of the upper surface 13h of the peripheral wall portion 13k without any step.

[0044] As shown in FIG. 4, the protruding portion 83 protrudes radially inward from the inner peripheral surface of the annular portion 81. In this embodiment, the protruding portion 83 has a quadrangular prism shape extending in the axial direction. The protruding portion 83 extends from the upper end to the lower end of the inner peripheral surface of the annular portion 81. The upper end of the protruding portion 83 is connected to the pressing portion 82. The radially inner end of the protruding portion 83 is located radially outward from the radially inner edge of the pressing portion 82. In this embodiment, the protruding portions 83 are provided at intervals in the circumferential direction. The multiple protruding portions 83 are provided at equal intervals around the circumference. For example, four protruding portions 83 are provided. As shown in FIG. 2, each protruding portion 83 is located inside each second recess 32c. Each protruding portion 83 is in contact with the inner surface of each second recess 32c. Each protruding portion 83 is filled in each second recess 32c, for example.

[0045] As shown in FIG. 3 and FIG. 4, the insertion portion 84 protrudes radially outward from the annular portion 81. More specifically, the insertion portion 84 protrudes radially outward from the lower end of the outer circumferential surface of the annular portion 81. In this embodiment, the insertion portion 84 is annular about the central axis J1. As shown in FIG. 3, the cross-sectional shape of the insertion portion 84 perpendicular to the circumferential direction is a triangle having an acute apex on the radially outer side. The upper surface of the insertion portion 84 is a tapered surface that is located lower as it goes radially outward. The lower surface of the insertion portion 84 is a flat annular surface perpendicular to the axial direction. The lower surface of the insertion portion 84 is connected to the radially outer side of the lower surface of the annular portion 81 without any step.

[0046] The insertion portion 84 is inserted into the first recess 13f. The insertion portion 84 contacts the inner surface of the first recess 13f. More specifically, the upper surface of the insertion portion 84 contacts the upper surface of the inner surface of the first recess 13f. The lower surface of the insertion portion 84 contacts the lower surface of the inner surface of the first recess 13f. In this embodiment, the insertion portion 84 fills the inside of the first recess 13f.

[0047] In this embodiment, the material constituting the fixing member 80 is a metal. The metal constituting the fixing member 80 is, for example, aluminum. Here, as described above, the material constituting the reduction gear case 13 made by die casting is an alloy containing aluminum. Therefore, the material constituting the peripheral wall portion 13k is also an alloy containing aluminum. In other words, in this embodiment, the material constituting the fixing member 80 and the material constituting the peripheral wall portion 13k each contain aluminum as the same type of metal.

[0048] The hardness of the material constituting the fixing member 80 is smaller than the hardness of the material constituting the internal gear 32 and the hardness of the material constituting the peripheral wall portion 13k. In this specification, "hardness" refers to, for example, Vickers hardness, Brinell hardness, Rockwell hardness, etc. The hardness of the material constituting the internal gear 32 is larger than the hardness of the material constituting the peripheral wall portion 13k. The rigidity of the material constituting the fixing member 80 is smaller than the rigidity of the material constituting the internal gear 32 and the rigidity of the material constituting the peripheral wall portion 13k. The Young's modulus of the material constituting the fixing member 80 is smaller than the Young's modulus of the material constituting the internal gear 32 and the Young's modulus of the material constituting the peripheral wall portion 13k.

[0049] As shown in FIG. 1, the flange portion 42 is an annular plate that spreads radially around the central axis J1. The flange portion 42 is located below the external gear 31. The flange portion 42 spreads radially outward from the output shaft 41 described below. More specifically, the flange portion 42 spreads radially outward from the upper end of the output shaft 41. The lower surface of the contact protrusion 31b contacts the radially inner portion of the upper surface of the flange portion 42. A cylindrical second sensor magnet 74 centered on the central axis J1 is fixed to the lower surface of the flange portion 42. The rotation of the output shaft 41 can be detected by detecting a change in the magnetic field generated by the second sensor magnet 74 that rotates together with the output portion 40 using a second rotation sensor (not shown).

[0050] The multiple protrusions 43 protrude upward from the flange portion 42. That is, the multiple protrusions 43 protrude from the flange portion 42 toward the external gear 31. As shown in Figs. 1 and 2, the protrusions 43 are hollow and cylindrical. The inside of the protrusions 43 opens downward. As shown in Fig. 2, the multiple protrusions 43 are arranged along the circumferential direction. More specifically, the multiple protrusions 43 are arranged at equal intervals around one circumference along the circumferential direction centered on the central axis J1. The number of protrusions 43 is, for example, eight.

[0051] The multiple protrusions 43 are inserted into the multiple hole portions 31c, respectively. The outer peripheral surface of the protrusions 43 is inscribed in the inner peripheral surface of the hole portion 31c. As a result, the multiple protrusions 43 support the external gear 31 via the inner surface of the hole portion 31c so as to be swingable around the central axis J1.

[0052] The output section 40 is a section that outputs the driving force of the electric actuator 10. As shown in Fig. 1, the output section 40 has an output shaft 41, a flange section 42, and a protruding section 43. In other words, the flange section 42 and the protruding section 43, which are parts of the above-mentioned speed reduction mechanism 30, are also parts of the output section 40. In this embodiment, the output section 40 is a single member.

[0053] In this embodiment, the output shaft 41 extends in the axial direction of the motor shaft 21 below the motor shaft 21. The output shaft 41 is cylindrical and centered on the central axis J1. The output shaft 41 extends downward from the radial inner edge of the flange portion 42. The output shaft 41 is fitted into the radial inner side of the bush 54. The output shaft 41 is supported by the bush 54 so as to be rotatable around the central axis J1. The output shaft 41 passes through the inside of the protruding cylindrical portion 13c. In this embodiment, the lower end of the output shaft 41 is located at the same position in the axial direction as the lower end of the protruding cylindrical portion 13c.

[0054] The output shaft 41 has an accommodating recess 41a and a connecting recess 41b. The accommodating recess 41a is recessed downward from the upper end of the output shaft 41. Although not shown, the accommodating recess 41a has a circular shape centered on the central axis J1 when viewed in the axial direction. The lower end of the motor shaft 21 is accommodated in the accommodating recess 41a. In this embodiment, the seventh shaft portion 21g and the eighth shaft portion 21h are accommodated in the accommodating recess 41a. The lower end surface of the motor shaft 21 is located above the bottom surface of the accommodating recess 41a. The lower end surface of the motor shaft 21 faces the bottom surface of the accommodating recess 41a in the axial direction via a gap.

[0055] The connecting recess 41b is recessed upward from the lower end of the output shaft 41. Although not shown, the connecting recess 41b has a substantially circular shape centered on the central axis J1 when viewed in the axial direction. A plurality of spline grooves are provided on the inner peripheral surface of the connecting recess 41b along the circumferential direction. Another member to which the driving force of the electric actuator 10 is output is inserted and connected to the connecting recess 41b. The other member is, for example, a manual shaft in a vehicle. The electric actuator 10 drives the manual shaft based on the driver's shift operation to switch the gears of the vehicle.

[0056] When the motor shaft 21 rotates around the central axis J1, the sixth shaft portion 21f, which is an eccentric shaft portion, revolves around the central axis J1 in the circumferential direction. The revolution of the sixth shaft portion 21f is transmitted to the external gear 31 via the second bearing 52, and the external gear 31 oscillates while changing the position where the inner peripheral surface of the hole portion 31c and the outer peripheral surface of the protrusion 43 are inscribed. As a result, the position where the gear portion of the external gear 31 and the gear portion of the internal gear 32 mesh with each other changes in the circumferential direction. Therefore, the rotational force of the motor shaft 21 is transmitted to the internal gear 32 via the external gear 31.

[0057] Here, in this embodiment, the internal gear 32 does not rotate because it is fixed to the reduction mechanism case 13. Therefore, the external gear 31 rotates around the eccentric axis J2 due to the reaction force of the rotational force transmitted to the internal gear 32. At this time, the direction of rotation of the external gear 31 is opposite to the direction of rotation of the motor shaft 21. The rotation of the external gear 31 around the eccentric axis J2 is transmitted to the flange portion 42 through the hole portion 31c and the protrusion portion 43. As a result, the output shaft 41 rotates around the central axis J1. In this way, the rotation of the motor shaft 21 is transmitted to the output shaft 41 through the reduction mechanism 30. The rotation of the output shaft 41 is reduced in speed by the reduction mechanism 30 with respect to the rotation of the motor shaft 21. According to the reduction mechanism 30 having the above-mentioned structure, the reduction ratio of the rotation of the output shaft 41 to the rotation of the motor shaft 21 can be made relatively large. Therefore, the rotation torque of the output shaft 41 can be made relatively large.

[0058] The preload member 60 is located axially between the outer ring of the third bearing 53 and the support wall portion 12f. The preload member 60 applies a downward elastic force to the outer ring of the third bearing 53. In this embodiment, the preload member 60 is, for example, a wave washer.

[0059] The circuit board 70 is in the form of a plate extending in a plane perpendicular to the axial direction. The circuit board 70 is accommodated in the motor case 12. More specifically, the circuit board 70 is accommodated in the circuit board accommodating portion 12g and disposed above and away from the annular plate portion 12b. The circuit board 70 is a board electrically connected to the motor 20. The coil 23b is electrically connected to the circuit board 70. The circuit board 70 controls, for example, the current supplied to the motor 20. For example, an inverter circuit is mounted on the circuit board 70.

[0060] The mounting member 72 is annular about the central axis J1. The inner peripheral surface of the mounting member 72 is fixed to the upper end of the motor shaft 21, i.e., the outer peripheral surface of the first shaft portion 21a. The first sensor magnet 73 is annular about the central axis J1. The first sensor magnet 73 is fixed to the upper end surface of the radially outer edge of the mounting member 72. The first sensor magnet 73 has N poles and S poles that are alternately arranged along the circumferential direction. The first rotation sensor 71 is attached to the lower surface of the circuit board 70. The first rotation sensor 71 can be used to detect the rotation of the motor shaft 21 by detecting a change in the magnetic field generated by the first sensor magnet 73 that rotates together with the motor shaft 21.

[0061] 5, the manufacturing method of the electric actuator 10 described above includes a fixing step FP in which the internal gear 32 is fixed to the case 11 using a fixing member 80. The fixing step FP includes an arrangement step S1 and a deformation step S2. The arrangement step S1 is a step of arranging the fixing member 180 before deformation and the internal gear 32 on the radial inside of the peripheral wall portion 13k. In this embodiment, the arrangement step S1 includes an internal gear arrangement step S1a and a fixing member arrangement step S1b.

[0062] The internal gear arranging step S1a is a step of arranging the internal gear 32 on the radial inside of the peripheral wall portion 13k. In the internal gear arranging step S1a, an operator arranges the internal gear 32 on the upper side of the bottom wall portion 13j as shown in Fig. 6. At this time, the annular protrusion 32b of the internal gear 32 is fitted into the radial inside of the stepped portion 13g.

[0063] In this specification, the term "workers, etc." includes workers who perform each task and assembly equipment, etc. Each task may be performed by a worker alone, by an assembly equipment alone, or by both a worker and an assembly equipment.

[0064] The fixing member arranging step S1b is a step of arranging the fixing member 180 before deformation on the radial inside of the peripheral wall portion 13k. In this embodiment, the fixing member arranging step S1b is performed after the internal gear arranging step S1a. If the internal gear 32 can be arranged after arranging the fixing member 180, the fixing member arranging step S1b may be performed before the internal gear arranging step S1a. As shown in FIG. 6, in the fixing member arranging step S1b, an operator or the like inserts the annular portion 181 of the fixing member 180 before deformation from above between the internal gear 32 and the peripheral wall portion 13k in the radial direction and arranges it. For example, a small gap is provided between at least one of the radial direction between the arranged annular portion 181 and the internal gear 32 and the radial direction between the annular portion 181 and the peripheral wall portion 13k. The axial dimension of the annular portion 181 is larger than the axial dimension of the annular portion 81 after deformation. The radial thickness between the inner and outer circumferential surfaces of the annular portion 181 is smaller than the radial thickness between the inner and outer circumferential surfaces of the deformed annular portion 81. The fixing member 180 arranged in the fixing member arrangement step S1b is in a state of protruding upward from the upper surface 13h of the peripheral wall portion 13k.

[0065] The deformation step S2 is a step of deforming the fixing member 180, in which the annular portion 181 is disposed between the internal gear 32 and the peripheral wall portion 13k in the radial direction, by pressing it downward from above against the bottom wall portion 13j. As shown in FIG. 6, the worker or the like applies a downward force to the fixing member 180 from above the holding portion 82. As a result, the fixing member 180 is crushed in the axial direction and deformed, becoming the deformed fixing member 80 shown in FIG. 3. The worker or the like uses, for example, a jig having a flat surface facing downward to apply a force from above to the holding portion 82 via the flat surface. The worker or the like crushes and deforms the fixing member 180 in the axial direction until, for example, the flat surface of the jig comes into contact with the upper surface 13h of the peripheral wall portion 13k.

[0066] In the deformation process S2, a part of the fixing member 180 is deformed and enters the first recess 13f. As a result, a part of the fixing member 180 is filled in the first recess 13f, and an insertion part 84 that conforms to the inner shape of the first recess 13f is created. The insertion part 84 is created, for example, by a part of the annular part 181 that is crushed in the axial direction entering the first recess 13f. As the annular part 181 is crushed in the axial direction in the deformation process S2, the lower surface of the pressing part 82 comes into contact with the upper surface 32e of the internal gear 32. Also, in the deformation process S2, the annular part 181 is deformed in a radially expanding direction and is pressed against the outer peripheral surface of the internal gear 32 and the inner peripheral surface of the peripheral wall part 13k. As a result, the internal gear 32 can be fixed to the peripheral wall part 13k by the deformed fixing member 80. In the deformation step S2, portions of the fixing member 180 other than the annular portion 181, such as the pressing portion 82, may also be deformed as appropriate.

[0067] According to this embodiment, the fixing member 80 is provided with an annular portion 81 that contacts the outer peripheral surface of the internal gear 32 and the inner peripheral surface of the peripheral wall portion 13k. The hardness of the material constituting the fixing member 80 is smaller than the hardness of the material constituting the internal gear 32 and the hardness of the material constituting the peripheral wall portion 13k. Therefore, as in the above-mentioned fixing step FP, the fixing member 180 before deformation can be easily deformed by being crushed in the axial direction between the internal gear 32 and the peripheral wall portion 13k in the radial direction. This allows the annular portion 81 after deformation to be strongly pressed against the outer peripheral surface of the internal gear 32 and the inner peripheral surface of the peripheral wall portion 13k. Therefore, the frictional force generated between the annular portion 81 and the outer peripheral surface of the internal gear 32 and between the annular portion 81 and the inner peripheral surface of the peripheral wall portion 13k can be relatively large, and the internal gear 32 can be firmly fixed to the peripheral wall portion 13k by the frictional force. Therefore, the fixing strength of the internal gear 32 to the case 11 can be improved. This makes it possible to prevent problems such as the internal gear 32 coming off the case 11 and the internal gear 32 shifting relative to the case 11.

[0068] Also, for example, when the internal gear 32 is directly press-fitted into the peripheral wall portion 13k, it is necessary to deform at least one of the peripheral wall portion 13k and the internal gear 32, which have a relatively high hardness. Therefore, when fixing the internal gear 32, it is necessary to apply a relatively large force to the internal gear 32, which may make it difficult to fix the internal gear 32. In contrast, according to the present embodiment, the internal gear 32 can be easily and suitably fixed by deforming the fixing member 180, which has a relatively low hardness. Therefore, the internal gear 32 can be easily fixed compared to when the internal gear 32 is fixed by press-fitting into the peripheral wall portion 13k. Therefore, it is possible to improve the ease of assembly of the electric actuator 10.

[0069] Moreover, according to this embodiment, the material constituting the fixing member 80 is metal. Therefore, as described above, the fixing member 180 before deformation can be easily deformed. Also, the fixing member 180 can be suitably deformed along the shape of the radial gap between the internal gear 32 and the peripheral wall portion 13k. Therefore, the fixing member 80 after deformation can be suitably brought into close contact with the internal gear 32 and the peripheral wall portion 13k. This makes it possible to increase the frictional forces between the fixing member 80 and the internal gear 32 and between the fixing member 80 and the peripheral wall portion 13k. Therefore, the fixing strength of the internal gear 32 to the case 11 can be further improved.

[0070] Further, according to the present embodiment, the material constituting the fixing member 80 and the material constituting the peripheral wall portion 13k each contain the same type of metal. Here, when the materials constituting two certain members each contain the same type of metal, the coefficient of friction between the two certain members tends to be relatively large. Therefore, by making the material constituting the fixing member 80 and the material constituting the peripheral wall portion 13k contain the same type of metal, the coefficient of friction between the fixing member 80 and the peripheral wall portion 13k can be relatively large. This makes it possible to more suitably increase the frictional force generated between the fixing member 80 and the peripheral wall portion 13k. Therefore, the fixing member 80 can be fixed more firmly to the peripheral wall portion 13k. Therefore, the fixing member 80 can fix the internal gear 32 more firmly to the peripheral wall portion 13k. This makes it possible to further improve the fixing strength of the internal gear 32 to the case 11.

[0071] According to the present embodiment, the inner peripheral surface of the peripheral wall portion 13k is provided with a first recess 13f recessed radially outward. The fixing member 80 has an insertion portion 84 inserted into the first recess 13f. The insertion portion 84 is in contact with the inner surface of the first recess 13f. Therefore, the fixing member 80 can be fixed more firmly to the peripheral wall portion 13k by the frictional force between the insertion portion 84 and the first recess 13f. This allows the fixing member 80 to fix the internal gear 32 more firmly to the peripheral wall portion 13k. Therefore, the fixing strength of the internal gear 32 to the case 11 can be further improved. In addition, since the insertion portion 84 is caught on the inner surface of the first recess 13f from below, it is possible to more effectively prevent the fixing member 80 from slipping out of the peripheral wall portion 13k to the upper side. Furthermore, as described above, in the deformation step S2, a portion of the fixing member 180 can be deformed and inserted into the first recess 13f, so that the portion of the fixing member 180 can escape into the first recess 13f when the fixing member 180 is deformed. This makes it easier to deform the fixing member 180 in the deformation step S2.

[0072] According to the present embodiment, the first recess 13f is annular and surrounds the internal gear 32. Therefore, the contact area between the insertion portion 84 and the first recess 13f can be increased. This increases the frictional force between the insertion portion 84 and the first recess 13f, and the fixing member 80 can be fixed more firmly to the peripheral wall portion 13k. This improves the fixing strength of the internal gear 32 to the case 11. When the fixing member 80 receives a force from above, the insertion portion 84 contacts the inner surface of the first recess 13f from below, and the force received can be dispersed in the circumferential direction. This prevents the force from being concentrated on the insertion portion 84, and prevents the insertion portion 84 from being damaged. In addition, in the deformation step S2, the amount of deformation of the fixing member 180 is easily made uniform over the entire circumference in the circumferential direction, and therefore the fixing member 180 can be deformed favorably. The first recess 13f can be easily formed by cutting out a part of the inner circumferential surface of the peripheral wall portion 13k over the entire circumference by cutting.

[0073] Moreover, according to this embodiment, the insertion portion 84 is filled inside the first recess 13f. Therefore, the contact area between the insertion portion 84 and the first recess 13f can be increased. This increases the frictional force between the insertion portion 84 and the first recess 13f, and the fixing member 80 can be fixed more firmly to the peripheral wall portion 13k. Therefore, the fixing strength of the internal gear 32 to the case 11 can be further improved.

[0074] Moreover, according to this embodiment, the fixing member 80 has a pressing portion 82 that protrudes radially inward from the upper end of the annular portion 81. The pressing portion 82 is in contact with the upper surface of the internal gear 32. Therefore, the pressing portion 82 can press the internal gear 32 from above. This allows the pressing portion 82 to prevent the internal gear 32 from shifting upward. In addition, the pressing portion 82 can increase the upper surface of the fixing member 80. Therefore, when applying force from above to the fixing member 180 before deformation to deform it, applying force to the pressing portion 82 makes it easier to apply force to the fixing member 180. This allows the fixing member 180 to be deformed more easily.

[0075] Furthermore, according to this embodiment, the upper surface 82a of the pressing portion 82 and the upper surface 13h of the peripheral wall portion 13k are disposed at the same position in the axial direction. Therefore, as described above, in the deformation step S2, a method can be adopted in which the fixing member 180 is deformed until the flat surface of the jig that presses the pressing portion 82 from above to below contacts the upper surface 13h of the peripheral wall portion 13k. Therefore, the timing to end the deformation step S2 can be easily grasped. This improves the workability in the deformation step S2.

[0076] Further, according to this embodiment, the internal gear 32 has a second recess 32c on the outer circumferential surface. The fixing member 80 has a protrusion 83 located inside the second recess 32c. Therefore, the protrusion 83 is caught in the circumferential direction on the inner surface of the second recess 32c. This makes it possible to more suitably suppress the relative rotation between the fixing member 80 and the internal gear 32. Therefore, the fixing member 80 and the internal gear 32 can be more firmly fixed. Therefore, the fixing strength of the internal gear 32 to the case 11 can be further improved. The protrusion 83 may be deformed along the inner surface of the second recess 32c by the deformation step S2. In this case, the protrusion 83 is firmly fixed in the second recess 32c, and the internal gear 32 and the fixing member 80 are more firmly fixed.

[0077] According to this embodiment, the bottom wall 13j has an annular stepped portion 13g on its upper surface surrounding the central axis J1. The internal gear 32 has an annular protruding portion 32b that protrudes downward and is fitted into the radially inner side of the stepped portion 13g. Therefore, the stepped portion 13g can position the internal gear 32 in the radial direction. This makes it possible to prevent the internal gear 32 from being displaced in the radial direction due to the deformation of the fixing member 180 when the fixing member 180 before deformation is deformed to fix the internal gear 32 to the peripheral wall 13k. Therefore, the internal gear 32 can be fixed with good axial accuracy.

[0078] The present invention is not limited to the above-described embodiment, and other configurations may be adopted. The material constituting the fixing member may be any material as long as it has a lower hardness than the material constituting the internal gear and the material constituting the peripheral wall. When the material constituting the fixing member is a metal, the metal constituting the fixing member may be copper or the like. The material constituting the fixing member may be other than a metal. The material constituting the fixing member and the material constituting the peripheral wall may not contain the same type of metal. The material constituting the internal gear and the material constituting the peripheral wall may contain the same type of metal.

[0079] The insertion portion of the fixing member may not be located in a part of the first recess as long as it is located at least in a part of the first recess. The insertion portion of the fixing member may not be provided. In this case, the inner peripheral surface of the peripheral wall portion may not be provided with the first recess. The shape of the first recess is not particularly limited, and it may not be annular. A plurality of first recesses may be provided. In this case, the fixing member may have a plurality of insertion portions inserted into each of the first recesses. The pressing portion of the fixing member may protrude from the peripheral wall portion toward the other axial side (upper side), or may be recessed from the peripheral wall portion toward one axial side (lower side). The pressing portion may not be provided. The number of the protruding portions of the fixing member and the number of the second recesses of the internal gear are not particularly limited. The protruding portion and the second recess may not be provided. The bottom wall portion of the case may not be provided with a step portion.

[0080] The use of the electric actuator of the above-mentioned embodiment is not particularly limited. The electric actuator of the above-mentioned embodiment may be mounted on equipment other than a vehicle. Furthermore, the configurations described in this specification may be appropriately combined within a range that does not contradict each other. [Explanation of symbols]

[0081] Reference Signs List 10...electric actuator, 11...case, 13f...first recess, 13g...step portion, 13j...bottom wall portion, 13k...circumferential wall portion, 20...motor, 21...motor shaft, 30...reduction mechanism, 31...external gear, 32...internal gear, 32b...annular protrusion portion, 32c...second recess, 80, 180...fixing member, 81, 181...annular portion, 82...pressing portion, 83...protruding portion, 84...insertion portion, FP...fixing step, J1...center axis, S2...deforming step

Claims

1. a motor having a motor shaft rotatable about a central axis extending in an axial direction; an external gear connected to the motor shaft; and an annular gear surrounding the radially outer side of the external gear. A reduction mechanism having an internal gear; a case that accommodates the motor and the reduction mechanism therein; A fixing member that fixes the internal gear to the case; Equipped with The case is a bottom wall portion supporting the internal gear from one axial side; A peripheral wall portion located radially outside the internal gear and surrounding the internal gear; having The fixing member surrounds the internal gear between the internal gear and the peripheral wall portion in the radial direction. The annular portion includes a the annular portion contacts an outer circumferential surface of the internal gear and an inner circumferential surface of the peripheral wall portion, The hardness of the material constituting the fixing member is determined by the hardness of the material constituting the internal gear and the The hardness is smaller than the hardness of the material constituting the peripheral wall portion, A first recess is provided on an inner circumferential surface of the peripheral wall portion and recessed radially outward, the fixing member has an insertion portion inserted into the first recess, The insertion portion is in contact with an inner surface of the first recess. Electric actuator.

2. a motor having a motor shaft rotatable about a central axis extending in an axial direction; an external gear connected to the motor shaft; and an annular gear surrounding the radially outer side of the external gear. A reduction mechanism having an internal gear; a case that accommodates the motor and the reduction mechanism therein; A fixing member that fixes the internal gear to the case; Equipped with The case is a bottom wall portion supporting the internal gear from one axial side; A peripheral wall portion located radially outside the internal gear and surrounding the internal gear; having The fixing member surrounds the internal gear between the internal gear and the peripheral wall portion in the radial direction. The annular portion includes a the annular portion contacts an outer circumferential surface of the internal gear and an inner circumferential surface of the peripheral wall portion, The hardness of the material constituting the fixing member is determined by the hardness of the material constituting the internal gear and the The hardness is smaller than the hardness of the material constituting the peripheral wall portion, The internal gear has a second recess on an outer circumferential surface, The fixing member has a protrusion located inside the second recess. Electric actuator.

3. The electric actuator according to claim 1 , wherein the material constituting the fixing member is a metal.

4. The material constituting the fixing member and the material constituting the peripheral wall portion are made of the same kind of metal. The electric actuator of claim 3 .

5. The electric actuator according to claim 1 , wherein the first recess is annular and surrounds the internal gear. Ta.

6. The electric actuator according to claim 1 , wherein the insertion portion is filled inside the first recess.

7. The fixing member has a pressing portion protruding radially inward from the other axial end of the annular portion. Has The pressing portion is in contact with a surface on the other axial side of the internal gear. The electric actuator according to any one of claims 1 to 5.

8. The other axial surface of the pressing portion and the other axial surface of the peripheral wall portion are 7. The electric actuator according to claim 6, wherein the actuators are arranged at the same position.

9. the bottom wall portion has an annular step portion surrounding the central axis on the other axial side surface, The internal gear is an annular gear that protrudes to one axial side and is fitted to the radially inner side of the stepped portion. The electric actuator according to claim 1 , further comprising a protrusion.

10. A motor having a motor shaft rotatable about a central axis extending in an axial direction; An external gear connected to a motor shaft and an annular internal gear surrounding the radially outer side of the external gear. a reduction mechanism having a gear; and a case for accommodating the motor and the reduction mechanism therein. A manufacturing method for an electric actuator comprising: A fixing step of fixing the internal gear to the case using a fixing member having an annular portion is included. 、 The case is a bottom wall portion supporting the internal gear from one axial side; A peripheral wall portion located radially outside the internal gear and surrounding the internal gear; having the hardness of the fixing member is lower than the hardness of the internal gear and the hardness of the peripheral wall portion, The fixing step includes disposing the annular portion between the internal gear and the peripheral wall portion in a radial direction. The fixing member in the state is pressed against the bottom wall portion from the other axial side toward the one axial side to change the state. A deformation process is included. In the deformation process, the annular portion is deformed to contact the outer circumferential surface of the internal gear and the peripheral wall portion. It is pressed against the inner circumferential surface, A first recess is provided on an inner circumferential surface of the peripheral wall portion and recessed radially outward, In the deformation process, a portion of the fixing member is deformed and enters into the first recess. A manufacturing method for an electric actuator.

11. a motor having a motor shaft rotatable about a central axis extending in an axial direction; an external gear connected to the motor shaft; and an annular gear surrounding the radially outer side of the external gear. A reduction mechanism having an internal gear; a case that accommodates the motor and the reduction mechanism therein; A fixing member that fixes the internal gear to the case; Equipped with The case is a bottom wall portion supporting the internal gear from one axial side; A peripheral wall portion located radially outside the internal gear and surrounding the internal gear; having The fixing member surrounds the internal gear between the internal gear and the peripheral wall portion in the radial direction. The annular portion includes a the annular portion contacts an outer circumferential surface of the internal gear and an inner circumferential surface of the peripheral wall portion, The hardness of the material constituting the fixing member is determined by the hardness of the material constituting the internal gear and the The hardness is smaller than the hardness of the material constituting the peripheral wall portion, A first recess is provided on an inner circumferential surface of the peripheral wall portion and recessed radially outward, a portion of the fixing member contacts an inner surface of the first recess; The internal gear has a second recess on an outer circumferential surface, A portion of the fixing member is located inside the second recess. Electric actuator.

Images