CN217115843U - Electric actuator - Google Patents

Abstract

The utility model provides an electric actuator, this electric actuator possess: a motor unit having a motor shaft that rotates about a central axis; a transmission mechanism connected to the motor shaft; an output shaft that rotates about an output axis parallel to the central axis, and to which power of the motor shaft is transmitted via a transmission mechanism; a first housing member that rotatably supports the motor shaft and the output shaft from one axial side; and a second housing part rotatably supporting the motor shaft and the output shaft from the other axial side. The first housing member is provided with a first positioning portion, the second housing member is provided with a second positioning portion, the first housing member and the second housing member are fixed in a state where the first positioning portion and the second positioning portion overlap each other when viewed from the axial direction, and the output shaft is arranged on an imaginary straight line passing through the central axis, the first positioning portion, and the second positioning portion when viewed from the axial direction.

Description

Electric actuator

Technical Field

The utility model relates to an electric actuator.

Background

Shift-by-wire systems are known that drive-control a rotary actuator according to a gear selected by a driver, thereby shifting the gear of an automatic transmission. As an actuator used for a shift-by-wire system, patent document 1 discloses a rotary actuator including a motor, a reduction gear, an output shaft, and a housing accommodating the motor, the reduction gear, and the output shaft.

Patent document 1: japanese laid-open patent publication No. 2018-194087

The housing of the actuator of patent document 1 has a front housing and a rear housing fastened to each other in the axial direction. The front housing and the rear housing rotatably support the input shaft and the output shaft from both sides in the axial direction, respectively. In such a configuration, even if the coaxiality of the input shafts of the front housing and the rear housing is ensured, the positional deviation of the output shaft cannot be eliminated, and there is a problem that the rotation efficiency of the output shaft is reduced.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is an object of the present invention to provide an electric actuator capable of improving the rotation efficiency of an output shaft.

In one aspect of the electric actuator of the present invention, the electric actuator includes: a motor unit having a motor shaft that rotates about a central axis; a transmission mechanism coupled to the motor shaft; an output shaft that rotates about an output axis parallel to the central axis, and to which power of the motor shaft is transmitted via the transmission mechanism; a first housing member that rotatably supports the motor shaft and the output shaft from one axial side; and a second housing part rotatably supporting the motor shaft and the output shaft from the other axial side. The first housing member is provided with a first positioning portion. A second positioning portion is provided at the second housing part. The first housing member and the second housing member are fixed in a state where the first positioning portion and the second positioning portion overlap each other when viewed from the axial direction. The output shaft is disposed on an imaginary straight line passing through the central axis, the first positioning portion, and the second positioning portion, as viewed in an axial direction.

In the electric actuator according to the above aspect, the first positioning portion and the second positioning portion each have a mirror-image symmetry shape with respect to the virtual straight line.

In the electric actuator according to the above aspect, the first positioning portion has a notch shape extending inward from an outer edge of the first housing member when viewed in the axial direction, and the second positioning portion has a notch shape extending inward from an outer edge of the second housing member when viewed in the axial direction.

According to the utility model discloses an aspect can improve the rotation efficiency of electric actuator's output shaft.

Drawings

Fig. 1 is a sectional view of an electric actuator according to an embodiment.

Fig. 2 is a perspective view of an electric actuator according to an embodiment.

Fig. 3 is a plan view of the electric actuator according to the embodiment as viewed from the lower side.

Fig. 4 is a perspective view of the first and second notch portions and a jig inserted into the first and second notch portions in the assembly process according to one embodiment.

Description of the reference symbols

9: a jig; 9 a: a first jig piece; 9 b: a second jig piece; 10: an electric actuator; 11: a housing; 12: a first housing member; 14: a second housing part; 40: a motor section; 41: a motor shaft; 50: a speed reduction mechanism (transmission mechanism); 61: an output shaft; 71: a first cutout portion (first positioning portion); 72: a second notch portion (second positioning portion); j1: a central axis; j3: an output axis; VL: an imaginary straight line.

Detailed Description

The Z axis shown in each figure represents the up-down direction. The positive side (+ Z side) of the Z axis is the upper side, and the negative side (-Z side) of the Z axis is the lower side. In the following description, a direction parallel to the Z axis is referred to as "vertical direction Z". In addition, an X axis and a Y axis appropriately shown in each drawing indicate one direction of horizontal directions perpendicular to the vertical direction Z, respectively. The X-axis and the Y-axis are perpendicular to each other. In the following description, a direction parallel to the X axis is referred to as a "first horizontal direction X", and a direction parallel to the Y axis is referred to as a "second horizontal direction Y". The positive side (+ X side) of the X axis is referred to as "one side of the first horizontal direction X", and the negative side (-X side) of the X axis is referred to as "the other side of the first horizontal direction X". The positive side (+ Y side) of the Y axis is referred to as "one side of the second horizontal direction Y", and the negative side (-Y side) of the Y axis is referred to as "the other side of the second horizontal direction Y". In the present embodiment, the vertical direction Z corresponds to a predetermined direction, the lower side corresponds to one side of the predetermined direction, and the upper side corresponds to the other side of the predetermined direction.

The vertical direction, the horizontal direction, the upper side, and the lower side are only names for describing relative positional relationships of the respective portions, and the actual positional relationship may be other than the positional relationship indicated by these names.

< electric actuator >

Fig. 1 is a sectional view of an electric actuator 10 of the present embodiment.

The electric actuator 10 of the present embodiment is mounted on a vehicle. More specifically, the electric actuator 10 is mounted on, for example, a parking-by-wire actuator device that is driven in accordance with a shift operation by a driver of the vehicle. The electric actuator 10 includes a motor unit 40, a speed reduction mechanism (transmission mechanism) 50, an output unit 60, a housing 11, a bus bar unit 90, a circuit board 70, a motor unit sensor 8, an output unit sensor 7, and a partition member 80.

Hereinafter, each part of the electric actuator 10 will be described based on the posture of the electric actuator 10 in the assembly process. Specifically, the portions of the electric actuator 10 will be described with respect to the case where the central axis J1 of the motor unit 40 is arranged parallel to the vertical direction Z. The posture of the electric actuator 10 when mounted on the vehicle is not particularly limited, and is not limited by the names such as the vertical direction Z used in the following description.

The center axis J1 of the motor portion 40 is appropriately shown by a one-dot chain line in each drawing. In the present embodiment, the central axis J1 extends in the vertical direction Z. In other words, in the following description, the up-down direction Z is the axial direction of the central axis J1. In the following description, unless otherwise specified, a radial direction about the central axis J1 will be simply referred to as a "radial direction", and a circumferential direction about the central axis J1 will be simply referred to as a "circumferential direction".

The motor unit 40 includes a rotor 40a, a first bearing 44a, a second bearing 44b, a third bearing 44c, a fourth bearing 44d, a stator 43, a magnet holder 46, a first sensor magnet 45, and a nut 48. That is, the electric actuator 10 includes a rotor 40a, a first bearing 44a, a second bearing 44b, a third bearing 44c, a fourth bearing 44d, a stator 43, a magnet holder 46, a first sensor magnet 45, and a nut 48. In the present embodiment, the first bearing 44a, the second bearing 44b, the third bearing 44c, and the fourth bearing 44d are, for example, ball bearings.

The rotor 40a rotates about a central axis J1 extending in the vertical direction Z. The rotor 40a has a motor shaft 41 and a rotor main body 42. That is, the motor unit 40 includes a motor shaft 41 and a rotor body 42. The motor shaft 41 extends in the vertical direction Z. The motor shaft 41 is rotatable about the center axis J1. The motor shaft 41 has an eccentric shaft portion 41a centered on an eccentric axis J2 eccentric with respect to the central axis J1. In the present embodiment, the eccentric shaft portion 41a is a part of the lower portion of the motor shaft 41. The third bearing 44c is fixed to the eccentric shaft portion 41 a. The eccentric axis J2 is parallel to the central axis J1. The eccentric shaft portion 41a is cylindrical and extends about an eccentric axis J2. The portion of the motor shaft 41 other than the eccentric shaft portion 41a is cylindrical and extends around the central axis J1.

As shown in fig. 2 and 3, the motor shaft 41 has a small diameter portion 41b, a medium diameter portion 41c, and a large diameter portion 41 g. In the present embodiment, the small diameter portion 41b, the intermediate diameter portion 41c, and the large diameter portion 41g are part of the upper portion of the motor shaft 41.

The small diameter portion 41b is located above the large diameter portion 41 g. In the present embodiment, the small diameter portion 41b is the uppermost portion of the motor shaft 41. The upper end of the small diameter portion 41b is the upper end of the motor shaft 41. The outer peripheral surface of the small diameter portion 41b is provided with a screw portion to which a nut 48 is fastened.

The small diameter portion 41b has a central recess 41i, the central recess 41i being recessed downward from an upper end of the small diameter portion 41b, and the central axis J1 passing through the central recess 41 i. The inner edge of the central recess 41i is circular as viewed from above, centered on the central axis J1. The inner surface of the central recess 41i is a tapered surface centered on the central axis J1 and having an inner diameter that decreases downward. The central recess 41i is a central hole formed by machining the motor shaft 41 using a lathe, for example.

The middle diameter portion 41c is connected to the lower side of the small diameter portion 41b via a step. The outer diameter of the middle diameter portion 41c is larger than the outer diameter of the small diameter portion 41 b. The first bearing 44a is fixed to the intermediate diameter portion 41 c. More specifically, the inner ring of the first bearing 44a is fitted into and fixed to the intermediate diameter portion 41 c. The upper end of the intermediate diameter portion 41c is located above the first bearing 44 a.

The large diameter portion 41g is connected to the lower side of the intermediate diameter portion 41c via a step. The large diameter portion 41g has an outer diameter larger than that of the medium diameter portion 41 c. The large diameter portion 41g is a portion of the motor shaft 41 to which the rotor body 42 is fixed. A rotor body 42 is fixed to the outer peripheral surface of the large diameter portion 41 g. The upper end of the large diameter portion 41g supports the inner ring of the first bearing 44a fixed to the medium diameter portion 41c from below.

The first bearing 44a, the second bearing 44b, the third bearing 44c, and the fourth bearing 44d are fixed to the motor shaft 41. The first bearing 44a and the second bearing 44b support the motor shaft 41 to be rotatable about the center axis J1. The first bearing 44a is a bearing that rotatably supports a portion of the motor shaft 41 located above the large diameter portion 41 g. In the present embodiment, the first bearing 44a is a bearing that rotatably supports the intermediate diameter portion 41 c. The second bearing 44b is a bearing that rotatably supports a portion of the motor shaft 41 located below the large diameter portion 41 g. In the present embodiment, the second bearing 44b is a bearing that rotatably supports the lower end portion of the motor shaft 41.

The rotor body 42 is fixed to the motor shaft 41. More specifically, the rotor body 42 is fixed to the large diameter portion 41 g. The rotor body 42 includes a rotor core 42a fixed to the motor shaft 41 and a rotor magnet 42b fixed to an outer peripheral portion of the rotor core 42 a. Although not shown, in the present embodiment, a plurality of rotor magnets 42b are provided at intervals in the circumferential direction.

The stator 43 is located radially outward of the rotor 40 a. More specifically, the stator 43 is disposed radially outward of the rotor body 42 with a gap therebetween. The stator 43 is annular surrounding the radially outer side of the rotor main body 42. The stator 43 includes, for example, a stator core 43a, an insulator 43b, and a plurality of coils 43 c. Each coil 43c is attached to a tooth of the stator core 43a via an insulator 43 b.

The magnet holder 46 is fixed to a portion of the motor shaft 41 located above the large diameter portion 41 g. The magnet holder 46 is substantially disc-shaped with the center axis J1 as the center. The magnet holder 46 is manufactured by, for example, press working a metal plate member. The magnet holder 46 is fixed to the motor shaft 41 by a nut 48.

The first sensor magnet 45 is fixed to the magnet holder 46. The first sensor magnet 45 is in the shape of a ring surrounding the motor shaft 41 when viewed in the vertical direction Z. The first sensor magnet 45 is, for example, annular with a center axis J1 as a center. The first sensor magnet 45 is, for example, a plate shape having a plate surface facing in the vertical direction Z. The plate surface of the first sensor magnet 45 is, for example, perpendicular to the vertical direction Z. The first sensor magnets 45 are arranged such that N poles and S poles alternate in the circumferential direction. The magnetic field of the first sensor magnet 45 is detected by the motor portion sensor 8.

The speed reduction mechanism 50 is located below the motor portion 40. The speed reduction mechanism 50 is coupled to the motor shaft 41. A partition member 80 is disposed between the speed reduction mechanism 50 and the stator 43 in the vertical direction Z. The speed reduction mechanism 50 is disposed below the rotor body 42 and the stator 43. The reduction mechanism 50 has an external gear 51, an internal gear 52, an output gear 53, and a plurality of protrusions 54.

The external gear 51 is in the form of a circular ring plate that extends in the radial direction of the eccentric axis J2, centered on the eccentric axis J2 of the eccentric shaft portion 41 a. The radially outer side surface of the external gear 51 is provided with a gear portion 51 b. The gear portion 51b of the external gear 51 has a plurality of teeth arranged along the outer periphery of the external gear 51.

The external gear 51 is coupled to the motor shaft 41. More specifically, the external gear 51 is coupled to the eccentric shaft portion 41a of the motor shaft 41 via the third bearing 44 c. Thereby, the speed reduction mechanism 50 is coupled to the motor shaft 41. The external gear 51 is fitted to the outer ring of the third bearing 44c from the radially outer side. Thereby, the third bearing 44c couples the motor shaft 41 and the external gear 51 to be relatively rotatable around the eccentric axis J2.

In the present embodiment, the external gear 51 has a plurality of holes 51 a. In the present embodiment, the hole 51a penetrates the external gear 51 in the vertical direction Z. The plurality of holes 51a are arranged in the circumferential direction. More specifically, the plurality of hole portions 51a are arranged at equal intervals over the entire circumference in the circumferential direction around the eccentric axis J2. Hole 51a has a circular shape when viewed in vertical direction Z. The inner diameter of the hole 51a is larger than the outer diameter of the protrusion 54. The hole 51a may have a bottom.

The internal gear 52 is positioned radially outward of the external gear 51, and is annular so as to surround the external gear 51. In the present embodiment, the internal gear 52 is annular with the center axis J1 as the center. The internal gear 52 is fixed to the housing 11. The internal gear 52 meshes with the external gear 51.

The output gear 53 is disposed above the external gear 51 and the internal gear 52. That is, the output gear 53 is disposed so as to overlap the external gear 51 when viewed in the vertical direction Z. The output gear 53 is connected to the motor shaft 41 via a fourth bearing 44 d. The output gear 53 is, for example, annular with the center axis J1 as the center when viewed in the vertical direction Z. A gear portion 53a is provided on the radially outer side surface of the output gear 53. The gear portion 53a has a plurality of tooth portions arranged along the outer periphery of the output gear 53. The gear portion 53a of the output gear 53 meshes with a gear portion 62a of the drive gear 62 described later.

The inner peripheral edge portion of the output gear 53 is disposed so as to face the lower side of the retainer ring 49 attached to the outer ring of the fourth bearing 44 d. The retainer ring 49 projects radially outward from the fourth bearing 44 d. The retainer ring 49 restrains the output gear 53 from moving upward relative to the fourth bearing 44 d.

The plurality of protruding portions 54 protrude from the output gear 53 toward the external gear 51 in the up-down direction Z. The plurality of protrusions 54 have a cylindrical shape protruding downward from the lower surface of the output gear 53. In the present embodiment, the plurality of projections 54 are integrally molded with the output gear 53. The plurality of projections 54 are arranged at equal intervals in the circumferential direction over the entire circumference.

The outer diameter of the protruding portion 54 is smaller than the inner diameter of the hole portion 51 a. The plurality of projections 54 are inserted into the plurality of holes 51a from above. The outer peripheral surface of the protruding portion 54 is inscribed in the inner surface of the hole 51 a. The plurality of projecting portions 54 support the external gear 51 via the inner surface of the hole 51a so as to be swingable around the central axis J1. As described above, in the present embodiment, since the movement of the output gear 53 to the upper side is suppressed by the retainer ring 49, the protrusion 54 provided on the output gear 53 is suppressed from being pulled out to the upper side from the hole portion 51 a.

The output portion 60 is a portion that outputs the driving force of the electric actuator 10. The output portion 60 is disposed radially outward of the motor portion 40. The output unit 60 includes an output shaft 61, a drive gear 62, a slide bearing 65, a second sensor magnet 63, and a magnet holder 64. That is, the electric actuator 10 includes the output shaft 61, the drive gear 62, the slide bearing 65, the second sensor magnet 63, and the magnet holder 64.

The output shaft 61 is cylindrical and extends in the vertical direction Z of the motor shaft 41. In this way, since the output shaft 61 extends in the same direction as the motor shaft 41, the structure of the speed reduction mechanism 50 that transmits the rotation of the motor shaft 41 to the output shaft 61 can be simplified. The output shaft 61 is coupled to the motor shaft 41 via the reduction mechanism 50. In the present embodiment, the output shaft 61 has a cylindrical shape centered on an output axis J3 parallel to the central axis J1.

The output axis J3 is the central axis of the output shaft 61. The output axis J3 is parallel to the central axis J1 and is disposed radially away from the central axis J1. That is, the motor shaft 41 and the output shaft 61 are disposed apart from each other in a direction perpendicular to the vertical direction Z. In other words, the motor shaft 41 and the output shaft 61 are arranged apart from each other in the radial direction of the motor shaft 41. Therefore, the electric actuator 10 can be downsized in the vertical direction Z as compared with the case where the motor shaft 41 and the output shaft 61 are arranged in the vertical direction Z. In fig. 1, the output axis J3 is located, for example, to the right of the central axis J1. The radial direction centered on the output axis J3 is referred to as an "output radial direction". The output radial direction is the radial direction of the output shaft 61.

The output shaft 61 is open on the lower side. The output shaft 61 has a spline groove on an inner peripheral surface. The output shaft 61 is disposed at a position overlapping the rotor body 42 in the radial direction of the motor shaft 41. A lower portion of the output shaft 61 is provided with a shaft flange portion 61 b. The shaft flange portion 61b protrudes outward in the output radial direction. The shaft flange portion 61b is annular and centered on the output axis J3.

The driven shaft DS is inserted into the output shaft 61 from below and coupled to the output shaft 61. More specifically, the output shaft 61 is coupled to the driven shaft DS by fitting a spline portion provided on the outer peripheral surface of the driven shaft DS into a spline groove provided on the inner peripheral surface of the output shaft 61. The driving force of the electric actuator 10 is transmitted to the driven shaft DS via the output shaft 61. Thereby, the electric actuator 10 rotates the driven shaft DS about the output axis J3.

The drive gear 62 is fixed to the output shaft 61. The drive gear 62 extends from the output shaft 61 toward the output gear 53. The drive gear 62 meshes with the output gear 53. Although not shown, the drive gear 62 has a substantially fan-like shape when viewed in the vertical direction Z, for example. The size of the drive gear 62 in the circumferential direction centered on the output axis J3 becomes larger toward the outer side in the output radial direction. The drive gear 62 has a gear portion at an outer end portion in the output radial direction. The gear portion 62a of the drive gear 62 has a plurality of tooth portions arranged in the circumferential direction around the output axis J3. The drive gear 62 meshes with the output gear 53. Thereby, the drive gear 62 is connected to the reduction mechanism 50. The rotation of the motor portion 40 is transmitted to the drive gear 62 via the reduction mechanism 50.

The magnet holder 64 is a substantially cylindrical member extending in the vertical direction Z about the output axis J3. The magnet holder 64 is open on both sides in the vertical direction Z. The magnet holder 64 is fixed to the upper portion of the output shaft 61. In the present embodiment, the magnet holder 64 is disposed radially outward of the first bearing 44a of the motor unit 40. The magnet holder 64 partially overlaps the circuit board 70 when viewed in the up-down direction Z. The magnet holder 64 is disposed below the circuit board 70. The output shaft 61 is press-fitted into the magnet holder 64.

The second sensor magnet 63 has an annular shape centered on the output axis J3. The second sensor magnet 63 is fitted to the upper end of the magnet holder 64. The second sensor magnet 63 is fixed to the magnet holder 64 by, for example, an adhesive. The magnet holder 64 is fixed to the output shaft 61, whereby the second sensor magnet 63 is fixed to the output shaft 61 via the magnet holder 64. A part of the second sensor magnet 63 faces the lower surface of the circuit board 70 with a gap.

The upper end of the output shaft 61 is located below the upper end of the magnet holder 64. An operation portion 66 into which a tool can be fitted is provided at an upper end of the output shaft 61. The operation portion 66 is, for example, a hole portion recessed downward from an upper end portion of the output shaft 61. The shape of the operation portion 66 is, for example, a square or a regular hexagon centered on the output axis J3 when viewed in the vertical direction Z.

When the motor shaft 41 rotates about the center axis J1, the eccentric shaft portion 41a revolves in the circumferential direction around the center axis J1. The revolution of the eccentric shaft portion 41a is transmitted to the external gear 51 via the third bearing 44c, and the external gear 51 oscillates while the position at which the inner circumferential surface of the hole 51a is inscribed in the outer circumferential surface of the protruding portion 54 changes. Thereby, the position at which the gear portion of the external gear 51 meshes with the gear portion of the internal gear 52 changes in the circumferential direction. Therefore, the rotational force of the motor shaft 41 is transmitted to the internal gear 52 via the external gear 51.

Here, in the present embodiment, the internal gear 52 does not rotate due to a second housing member 14, which will be described later, fixed to the housing 11. Therefore, the external gear 51 rotates about the eccentric axis J2 by the reaction force of the rotational force transmitted to the internal gear 52. At this time, the direction in which the external gear 51 rotates is opposite to the direction in which the motor shaft 41 rotates. The rotation of the external gear 51 about the eccentric axis J2 is transmitted to the output gear 53 via the hole portion 51a and the protruding portion 54. Thereby, the output gear 53 rotates about the center axis J1. The rotation of the motor shaft 41 is decelerated and transmitted to the output gear 53.

When the output gear 53 rotates, the drive gear 62 meshed with the output gear 53 rotates about the output axis J3. Thereby, the output shaft 61 fixed to the drive gear 62 rotates about the output axis J3. In this way, the rotation of the motor unit 40 is transmitted to the output shaft 61 via the reduction mechanism 50. That is, the power of the motor shaft 41 is transmitted to the output shaft 61 via the reduction mechanism 50, and the output shaft 61 rotates about the output axis J3. With such a configuration of the speed reduction mechanism 50, the rotation of the output shaft 61 can be relatively greatly reduced with respect to the rotation of the motor shaft 41. Therefore, the rotational torque of the output shaft 61 can be made relatively large. Therefore, the electric actuator 10 can be miniaturized and the output of the electric actuator 10 can be easily ensured. In the electric actuator 10 of the present embodiment, the output shaft 61 rotates bidirectionally within a range of less than one rotation.

The housing 11 houses the motor section 40, the speed reduction mechanism 50, the output section 60 including the output shaft 61, the circuit board 70, the bus bar unit 90, and the partition member 80. The housing 11 has a first housing part 12, a cover part 13 and a second housing part 14. That is, the electric actuator 10 includes a first housing member 12, a cover member 13, and a second housing member 14. In the present embodiment, the first housing member 12 rotatably supports the motor shaft 41 and the output shaft 61 from the upper side (one axial side). The second housing part 14 rotatably supports the motor shaft 41 and the output shaft 61 from the lower side (the other side in the axial direction).

The first housing member 12 internally houses the stator 43. The first housing part 12 has an opening 12a opening upward and an opening 12b opening downward. In the present embodiment, the first housing member 12 is made of metal. The first housing part 12 is formed, for example, by die casting. The first housing member 12 has a polygonal shape when viewed in the vertical direction Z, for example.

The first housing part 12 has: a square-cylindrical outer wall portion 30 that constitutes a housing of the electric actuator 10; a bottom wall portion 31 that extends radially inward from a lower end of the outer wall portion 30; and a motor housing portion 32 and an output shaft upper holding portion 33 provided to the bottom wall portion 31. That is, the housing 11 has an outer wall portion 30, a bottom wall portion 31, a motor housing portion 32, and an output shaft upper holding portion 33.

In the present embodiment, the outer wall portion 30 has a pentagonal square-cylindrical shape when viewed in the vertical direction Z. The outer wall portion 30 surrounds the motor housing portion 32 from the radially outer side. The upper opening of the outer wall portion 30 is an upper opening 12a of the first housing member 12. The bottom wall 31 has an opening that opens downward. A cylindrical wall 38 protruding downward from the bottom wall 31 is provided at the periphery of the opening of the bottom wall 31. The cylindrical wall 38 is annular surrounding the central axis J1 and the output axis J3. The opening surrounded by the cylindrical wall 38 is the opening 12b on the lower side of the first housing member 12.

The motor housing portion 32 and the output shaft upper holding portion 33 are provided on the upper surface of the bottom wall portion 31. The motor housing portion 32 has a cylindrical shape surrounding the motor portion 40 from the radially outer side. In the present embodiment, the motor housing portion 32 has a cylindrical shape that is open downward around the central axis J1. The motor housing portion 32 holds the motor portion 40 inside. More specifically, the stator 43 of the motor unit 40 is fixed to the inner circumferential surface of the motor housing 32. The motor housing portion 32 has: a cylindrical portion 32b extending upward from the bottom wall portion 31; an annular plate-shaped partition wall 32a that extends radially inward from an upper end of the cylindrical portion 32 b; and a substrate fixing portion 32 h.

The partition wall 32a has a first bearing holding portion 32c that holds the first bearing 44a at the center as viewed in the vertical direction Z. That is, the first housing member 12 has the first bearing holding portion 32 c. The first bearing holding portion 32c is cylindrical and extends in the vertical direction Z around the central axis J1. The first bearing holding portion 32c is open on the lower side. The first bearing 44a is held by the inner peripheral surface of the first bearing holding portion 32 c. The first bearing 44a is fitted with a clearance radially inside the first bearing holding portion 32 c.

The partition wall 32a also serves as a bearing holder, and thus the electric actuator 10 can be prevented from being increased in size in the vertical direction Z. The inner peripheral edge portion of the lower end portion of the first bearing holding portion 32c is chamfered. Thus, the inner diameter of the lower end of the first bearing holding portion 32c increases toward the lower side.

The blocking wall 32a has a guide hole 32f penetrating the blocking wall 32a in the up-down direction Z. The guide hole 32f is provided in a portion of the blocking wall 32a that is located radially inward of the inner peripheral surface 32e of the first bearing holding portion 32 c. The guide hole 32f is, for example, a circular hole centered on the central axis J1. The end portion of the lower side of the guide hole 32f opens inside the first bearing holder 32 c. Thereby, the inside of the guide hole 32f is connected to the inside of the first bearing holder 32c on the upper side of the first bearing holder 32 c.

The substrate fixing portion 32h protrudes upward from the partition wall 32 a. A plurality of substrate fixing portions 32h are provided. The substrate fixing portion 32h has a cylindrical shape. The substrate fixing portion 32h supports the circuit board 70 from below. An upper end surface of the substrate fixing portion 32h is provided with a female screw hole. The bolt 96 penetrating the circuit board 70 in the vertical direction Z is screwed into the female screw hole of the substrate fixing portion 32h from the upper side. Thereby, the circuit board 70 is fixed to the substrate fixing portion 32 h.

The output shaft upper holding portion 33 is cylindrical with the output axis J3 as the center. The output shaft upper holding portion 33 protrudes downward from the bottom wall portion 31. A part of the side surface of the output shaft upper holding portion 33 is connected to the side surface of the motor housing portion 32. The output shaft upper holding portion 33 has a hole portion 33a penetrating the output shaft upper holding portion 33 in the vertical direction Z. A cylindrical sliding bearing 65 is fitted inside the hole 33 a.

Fig. 2 is a perspective view of the electric actuator 10.

The first housing part 12 has a fixing portion 34. The fixing portion 34 has a female screw hole 36 in a lower end surface. That is, the first housing member 12 has a female screw hole (not shown) recessed upward. The first housing part 12 is provided with a plurality of fixing portions 34. The plurality of fixing portions 34 are disposed along the periphery of the cylindrical wall 38 with a space therebetween, so as to surround the cylindrical wall 38.

The first housing part 12 has a fastening face 37 facing downwards. The fastening surface 37 is, for example, a flat surface perpendicular to the vertical direction Z. The fastening surface 37 is, for example, a machined surface. In the present specification, the phrase "a certain surface is a machined surface" means that a certain surface is produced by performing machining such as cutting or grinding. In the present embodiment, the fastening surface 37 is a surface formed by cutting the surface of the first housing part 12 molded by die casting.

The outer edge of the fastening surface 37 of the first housing part 12 is provided with a first cutout (first positioning portion) 71. That is, the first housing part 12 is provided with the first cutout portion 71. The first notch portion 71 is shaped like a notch extending inward from the outer edge of the first housing member 12 when viewed in the axial direction. The first cutout portion 71 is for positioning the first housing member 12 and the second housing member 14 in the circumferential direction about the central axis J1. The structure of the first notch portion 71 will be described in detail together with the following description of the method of manufacturing the electric actuator 10.

As shown in fig. 1, the lid member 13 is a container-like member having a recess 13b that opens downward. In the present embodiment, the lid member 13 is made of metal. The cover member 13 is molded by, for example, die casting. The cover member 13 is fixed to the upper side of the first housing member 12. More specifically, the cover member 13 and the first housing member 12 are fastened by a plurality of bolts penetrating the cover member 13 in the vertical direction Z. The cover member 13 closes the opening 12a on the upper side of the first housing member 12. Although not shown, the recess 13b accommodates an electronic component mounted on the upper surface of the circuit board 70. The recess 13b accommodates, for example, a capacitor, a transistor, and the like mounted on the circuit board 70. The cover member 13 covers the output shaft 61 from the upper side.

The cover member 13 has an insertion hole 13c located on the upper side of the output shaft 61. The insertion hole 13c overlaps the operation portion 66 when viewed in the up-down direction Z. The insertion hole 13c is mounted with a detachable plug member 15. For example, the plug member 15 is detachably attached to the insertion hole 13c by screwing a male screw portion provided on the outer peripheral surface into a female screw portion provided on the inner peripheral surface of the insertion hole 13 c. Thereby, the insertion hole 13c is openably closed by the plug member 15 detachably attached. Therefore, foreign matter can be suppressed from entering the interior of the electric actuator 10 from the insertion hole 13 c.

On the other hand, by removing the plug member 15, a tool such as a polygonal column wrench can be inserted into the operation portion 66 from the outside of the electric actuator 10 through the insertion hole 13 c. This enables the tool to be coupled to the output shaft 61. When the tool is coupled to the output shaft 61, the output shaft 61 can be rotated by rotating the tool about the output axis J3.

The second housing part 14 covers the reduction mechanism 50 from the lower side. In the present embodiment, the second housing member 14 is made of metal. The second housing part 14 is formed, for example, by die casting. The second housing part 14 is secured to the underside of the first housing part 12. In more detail, as shown in fig. 2, the second housing part 14 is fixed to the lower side of the first housing part 12 by a plurality of bolts 97. The bolt 97 is screwed into the female screw hole of the fixing portion 34. In addition, the second housing part 14 may be fastened to the first housing part 12 by fastening a plate-shaped bracket thereto.

As shown in fig. 1, the second housing part 14 closes the opening portion 12b of the lower side of the first housing part 12. The second housing member 14 has a receiving portion 14p and a flange portion 14 c. The housing portion 14p is a container-shaped portion that opens upward. The housing portion 14p houses the speed reduction mechanism 50 therein. Thereby, the second housing member 14 internally houses the speed reduction mechanism 50. The housing portion 14p has a second bearing holding portion 14a, an inner bottom wall portion 14f, an inner peripheral wall portion 14b, an outer bottom wall portion 14j, an outer peripheral wall portion 14k, and a cylindrical portion 14 r. That is, the second housing member 14 has a second bearing holding portion 14a, an inner bottom wall portion 14f, an inner peripheral wall portion 14b, an outer bottom wall portion 14j, an outer peripheral wall portion 14k, and a cylindrical portion 14 r.

The second bearing holding portion 14a is cylindrical with the center axis J1 as the center. The second bearing retainer 14a is open to the upper side and has a bottom 14d on the lower side. The inner diameter of the second bearing holding portion 14a is smaller than the inner peripheral wall portion 14b, and is located below the inner peripheral wall portion 14 b. The second bearing holding portion 14a holds the second bearing 44 b. The second bearing 44b is fitted radially inward of the second bearing holding portion 14 a. More specifically, the second bearing 44b is fitted with a clearance in the radial direction inside the second bearing holding portion 14 a. A preload member 47 is disposed between the second bearing 44b and the bottom portion 14d in the vertical direction Z. The preload member 47 is, for example, an annular wave washer extending in the circumferential direction. The preload member 47 contacts the upper surface of the bottom portion 14d and the lower end of the outer race of the second bearing 44 b. The preload member 47 applies an upward preload to the outer race of the second bearing 44 b.

The inner bottom wall portion 14f extends radially outward from an upper end of the second bearing holder 14 a. The inner bottom wall portion 14f is annular centered on the central axis J1. The inner peripheral wall portion 14b extends upward from the outer peripheral edge portion of the inner bottom wall portion 14 f. The inner peripheral wall portion 14b is located radially outward of the second bearing holding portion 14 a. The inner peripheral wall portion 14b is cylindrical with the center axis J1 as the center. The inner peripheral wall 14b is open to the upper side. The internal gear 52 is fitted inside the inner peripheral wall portion 14 b. In the present embodiment, the internal gear 52 is press-fitted into the inner peripheral wall portion 14 b.

The outer bottom wall portion 14j extends radially outward from an upper end of the inner peripheral wall portion 14 b. The outer shape of the outer bottom wall portion 14j as viewed in the vertical direction Z is the same as the outer shape of the cylindrical wall 38 as viewed in the vertical direction Z. The outer peripheral wall portion 14k extends upward from the outer peripheral edge portion of the outer bottom wall portion 14 j. The outer peripheral wall portion 14k is located radially outward of the inner peripheral wall portion 14 b. The outer shape of the outer peripheral wall portion 14k as viewed in the vertical direction Z is the same as the outer shape of the cylindrical wall 38 as viewed in the vertical direction Z. The outer peripheral wall 14k has an opening 14s that opens upward. The opening 14s of the second housing member 14 faces the lower opening 12b of the first housing member 12 in the vertical direction Z. The output gear 53 is housed radially inside the outer peripheral wall portion 14 k.

As shown in fig. 2, the cylindrical portion 14r protrudes downward from the outer bottom wall portion 14 j. The cylindrical portion 14r is cylindrical and opens on both sides in the vertical direction, centering on the output axis J3. An output shaft lower holding portion 14e that opens downward is provided on the inner surface of the cylindrical portion 14 r. As shown in fig. 1, the output shaft lower holding portion 14e and the output portion 60 overlap in the vertical direction Z. The packing 61c is fitted into the outer peripheral surface of the lower end portion of the output shaft 61. The output shaft lower holding portion 14e rotatably supports the output shaft 61 via a packing 61 c. The lower end portion of the output shaft 61 is exposed downward through the output shaft lower holding portion 14 e. The upper end of the cylindrical portion 14r supports the shaft flange portion 61b from below.

The flange portion 14c extends radially outward from an upper end of the housing portion 14 p. In the present embodiment, the flange portion 14c extends radially outward from the upper end of the outer peripheral wall portion 14 k. The flange portion 14c is annular and surrounds the opening portion 14s on the upper side of the housing portion 14 p. In the present embodiment, the flange portion 14c surrounds the central axis J1 and the output axis J3.

As shown in fig. 2, the flange portion 14c has a through hole 14i penetrating the flange portion 14c in the vertical direction Z. The through hole 14i is provided in plural. The through-holes 14i are provided with, for example, six. The plurality of through holes 14i are arranged at intervals in the circumferential direction in which the flange portion 14c extends. The bolt 97 passes through the through hole 14 i.

The flange portion 14c has a fastening surface 14m facing upward. The fastening surface 14m is, for example, a flat surface perpendicular to the vertical direction Z. The fastening surface 14m is, for example, a machined surface. In the present embodiment, the fastening surface 14m is a surface formed by cutting the surface of the second housing member 14 formed by die casting.

The fastening face 14m of the second housing part 14 is in contact with the fastening face 37 of the first housing part 12. The fastening face 14m of the second housing part 14 is fixed with respect to the fastening face 37 of the first housing part 12 by means of bolts 97.

The outer edge of the fastening surface 14m of the second housing part 14 is provided with a second cutout portion (second positioning portion) 72. That is, the second housing part 14 is provided with the second cutout portion 72. The second cutout portion 72 has a cutout shape extending inward from the outer edge of the second housing member 14 when viewed in the axial direction. The second cutout portion 72 is for positioning the first housing member 12 and the second housing member 14 in the circumferential direction about the central axis J1. The first housing member 12 and the second housing member 14 are fixed in a state where the first cutout portion 71 and the second cutout portion 72 overlap each other when viewed in the axial direction. The structure of the second notch portion 72 will be described in detail together with the following description of the method of manufacturing the electric actuator 10.

As shown in fig. 1, the bus bar unit 90 is disposed on the upper surface of the partition wall 32 a. The bus bar unit 90 has a ring-plate-shaped bus bar holder 91 and a plurality of bus bars 92 held by the bus bar holder 91. The bus bar 92 is provided with, for example, six. In the present embodiment, the bus bar holder 91 is manufactured by insert molding in which the bus bar 92 is an insert member. The bus bar holder 91 is fixed to the partition wall 32a of the motor case 32 by a plurality of bolts 95, for example. The bolts 95 are provided with three, for example.

One end 92a of the bus bar 92 protrudes upward from the upper surface of the bus bar holder 91. In the present embodiment, the end portion 92a of the bus bar 92 on one side penetrates the circuit board 70 from the lower side to the upper side. The end portion 92a is electrically connected to the circuit board 70 at a position penetrating the circuit board 70 by a connection method such as soldering, welding, press-fitting, or the like. Although not shown, the other end of the bus bar 92 grips a coil lead wire drawn from the coil 43c of the stator 43 and is connected to the coil 43c by welding or fusing. Thereby, the stator 43 and the circuit board 70 are electrically connected via the bus bar 92.

In the present embodiment, the circuit board 70 is disposed above the motor portion 40 and the bus bar unit 90. The circuit board 70 has a plate shape whose plate surface is perpendicular to the vertical direction Z. The circuit board 70 mounts the motor portion sensor 8 and the output portion sensor 7. Although not shown, the shape of the circuit board 70 as viewed in the up-down direction Z is substantially square. The circuit board 70 is electrically connected to the coil 43c of the stator 43 via the bus bar unit 90. That is, the circuit board 70 is electrically connected to the motor portion 40. In the present embodiment, the circuit board 70 is housed inside the opening 12a of the first housing member 12. The circuit board 70 is covered from the upper side by the cover member 13. The circuit board 70 is fixed to the substrate fixing portion 32h of the motor case portion 32 by a plurality of bolts 96, for example.

The motor portion sensor 8 is fixed to the lower surface of the circuit board 70. More specifically, the motor portion sensor 8 is fixed to a portion of the lower surface of the circuit board 70 that faces the first sensor magnet 45 in the vertical direction Z with a gap therebetween. The motor portion sensor 8 is a magnetic sensor capable of detecting the magnetic field of the first sensor magnet 45. The motor sensor 8 is a hall element such as a hall IC. Although not shown, for example, three motor portion sensors 8 are provided in the circumferential direction. The motor portion sensor 8 detects the rotation position of the first sensor magnet 45 by detecting the magnetic field of the first sensor magnet 45, thereby detecting the rotation of the motor shaft 41.

The output section sensor 7 is fixed to the lower surface of the circuit board 70. More specifically, the output portion sensor 7 is fixed to a portion of the lower surface of the circuit board 70 that faces the second sensor magnet 63 in the vertical direction Z with a gap therebetween. The output portion sensor 7 is a magnetic sensor capable of detecting the magnetic field of the second sensor magnet 63. The output sensor 7 is a hall element such as a hall IC, for example. The output portion sensor 7 detects the rotation position of the second sensor magnet 63 by detecting the magnetic field of the second sensor magnet 63, thereby detecting the rotation of the output shaft 61.

< method for manufacturing electric actuator >

In the present embodiment, the method of manufacturing (assembling) the electric actuator 10 mainly includes a first preliminary step, a fixing step, a second preliminary step, and a cover member fixing step.

In the specification, "an operator or the like" includes an operator, an assembling device, and the like that perform each operation. Each operation may be performed only by an operator, only by the assembly device, or by both the operator and the assembly device. The first preliminary step and the fixing step of the electric actuator 10 according to the present embodiment are performed by an assembly device not shown.

The first preliminary step is a step of assembling the motor section 40, the speed reduction mechanism 50, and the output section 60 to the first housing member 12 and the second housing member 14. In the first preliminary step, the stator 43 is assembled to the first housing member 12. On the other hand, the reduction mechanism 50, the output section 60, and the rotor 40a are assembled to the second housing member 14.

Further, in the first preliminary step, the first housing member 12 is attached to the assembly apparatus such that the opening 12b faces downward. In the first preliminary step, the second housing member 14 is attached to the assembly apparatus such that the opening 14s faces upward. The opening 12b of the first housing member 12 and the opening 14s of the second housing member 14 face each other with a gap therebetween in the vertical direction.

The fixing process is a process of fixing the first housing part 12 and the second housing part 14 to each other. The fixing process comprises a sealing process, a circumferential alignment process and a fastening process. The closing step is a step of bringing the first housing member 12 and the second housing member 14 into contact with each other and closing the openings 12b and 14. The circumferential alignment step is a step of aligning the first housing member 12 and the second housing member 14 in the circumferential direction around the central axis J1. The fastening step is a step of fastening the first housing member 12 and the second housing member 14 to each other by fastening the bolts 97.

In the closing step, the assembling apparatus closes the first housing member 12 and the second housing member 14 in the vertical direction, and closes the openings 12b and 14 s. Thereby, the fastening face 37 of the first housing part 12 and the fastening face 14m of the second housing part 14 are in contact with each other.

The sealing step is performed using the assembly apparatus. The closing process is performed while performing the alignment of the first housing member 12 and the second housing member 14 with respect to the central axis J1. In the closing step, the assembling apparatus brings the first housing member 12 and the second housing member 14 close to each other while ensuring the coaxiality between the guide hole 32f of the first housing member 12 and the rotor 40a assembled to the second housing member 14. Thereby, the coaxiality of the first housing member 12 and the second housing member 14 with respect to the central axis J1 can be improved. Thereby, the motor shaft 41 is suppressed from being held in a twisted manner between the first housing part 12 and the second housing part 14, so that the rotational efficiency of the motor shaft 41 can be improved.

Fig. 3 is a plan view seen from the lower side of the electric actuator 10.

The circumferential alignment process is performed after the sealing process. In addition, the circumferential aligning process is performed in a state where the coaxiality of the first housing member 12 and the second housing member 14 with respect to the central axis J1 is maintained. By performing the closing step, the first cut portion 71 of the first housing member and the second cut portion 72 of the second housing member 14 overlap at least partially when viewed in the axial direction. However, the first housing member 12 and the second housing member 14 may be displaced in the circumferential direction about the central axis J1, and therefore the first cutout portion 71 and the second cutout portion 72 do not completely overlap.

The circumferential alignment step is performed using a jig 9. In the circumferential alignment step, an operator or the like inserts the jig 9 into the first notch portion 71 and the second notch portion 72. The jig 9 is in contact with the opening edge of the first cutout portion 71 and the opening edge of the second cutout portion, respectively. As a result, one or both of the first housing member 12 and the second housing member 14 are relatively rotated about the central axis J1, and the circumferential alignment is completed. After the circumferential alignment step, the fastening step is performed while maintaining the relative positional relationship between the first housing member 12 and the second housing member 14.

According to the present embodiment, in the fixing step, the worker or the like fixes the first housing member 12 and the second housing member 14 to each other in a state where the first notch portion 71 and the second notch portion 72 are overlapped with each other when viewed from the axial direction and the jig 9 is inserted into the first notch portion 71 and the second notch portion 72. The fixing step is performed while the first housing member 12 and the second housing member 14 are aligned with respect to the central axis J1.

By performing the closing process, the coaxiality on the central axis J1 of the first housing member 12 and the second housing member 14 is improved, but the coaxiality on the output axis J3 is not ensured. If the positional deviation of the first housing member 12 and the second housing member 14 on the output axis J3 is generated, the output shaft 61 is twisted, so that the rotational efficiency of the output shaft 61 may be reduced.

According to the present embodiment, the alignment step of the first housing member 12 and the second housing member 14 in the circumferential direction around the center axis J1 can be performed by performing the fixing step in a state where the jig 9 is inserted into the first notch portion 71 and the second notch portion 72 by an operator or the like. Therefore, the first housing member 12 and the second housing member 14 can be aligned on the output axis J3. That is, the coaxiality of the first housing member 12 and the second housing member 14 on the output axis J3 can be improved. As a result, the output shaft 61 can be prevented from being held between the first housing member 12 and the second housing member 14 in a twisted manner, and the rotation efficiency of the output shaft 61 can be improved.

Here, as shown in fig. 3, when the electric actuator 10 is viewed from the axial direction, a virtual straight line VL passing through the central axis J1 and the first and second notch portions 71 and 72 is assumed.

When viewed from the axial direction, the virtual straight line VL passes through the centers of the first notch portion 71 and the second notch portion 72. The output shaft 61 is disposed on the virtual straight line VL. In particular, in the present embodiment, the imaginary straight line VL is disposed on the output axis J3 passing through the center of the output shaft 61. That is, the central axis J1, the output axis J3, and the first notch portion 71 and the second notch portion 72 are arranged on the virtual straight line VL.

As shown in fig. 1, the first housing member 12 rotatably supports the motor shaft 41 in the first bearing holding portion 32c via the first bearing 44 a. The first housing member 12 rotatably supports the output shaft 61 in the output shaft upper holding portion 33 via a sliding bearing 65.

In order to ensure dimensional accuracy, the first bearing holding portion 32c, the output shaft upper holding portion 33, and the first cut portion 71 of the first housing member 12 are machined by an end mill or the like. Similarly, the second bearing holding portion 14a, the output shaft lower side holding portion 14e, and the second notch portion 72 of the second housing member 14 are machined.

According to the present embodiment, the center axis J1, the output axis J3, and the first cutout 71 are arranged on the imaginary straight line VL in the first case member 12. Therefore, when the first bearing holding portion 32c, the output shaft upper holding portion 33, and the first notch portion 71 are machined, the movement direction of the main shaft of the machine tool can be aligned with the direction of the virtual straight line VL, and thus the main shaft can be machined without moving in the direction perpendicular to the virtual straight line VL. As a result, the dimensional accuracy of the first bearing holding portion 32c, the output shaft upper holding portion 33, and the first notch portion 71 with respect to the virtual straight line VL can be improved. Accordingly, the dimensional accuracy of the output axis J3 in the circumferential direction of the central axis J1 and the first notch portion 71 can be improved by machining the first housing part 12.

Similarly, the second housing part 14 rotatably supports the motor shaft 41 via the second bearing 44b in the second bearing holder 14 a. The second housing member 14 rotatably supports the output shaft 61 via a spacer 61c in the output shaft lower holding portion 14 e. According to the present embodiment, when machining the second bearing holder 14a, the output shaft lower holder 14e, and the second notch 72, the movement direction of the main shaft of the machine tool can be made to coincide with the direction of the virtual straight line VL, so that the machine tool can be machined without moving the main shaft in the direction perpendicular to the virtual straight line VL. As a result, the dimensional accuracy of the second bearing holding portion 14a, the output shaft lower side holding portion 14e, and the second notch portion 72 with respect to the virtual straight line VL can be improved. Accordingly, the dimensional accuracy of the output axis J3 and the first notch portion 71 in the circumferential direction of the central axis J1 can be improved by the machining of the second housing part 14.

In this way, according to the present embodiment, the positional accuracy of the portions of the first and second housing parts 12 and 14 that hold the output shaft 61 and the first and second notch portions 71 and 72 in the circumferential direction of the central axis J1 is improved. Thus, by positioning the first notch portion 71 and the second notch portion 72 in the circumferential direction of the central axis J1, the positional accuracy of the portions of the first housing member 12 and the second housing member 14 that hold the output shaft 61 (the output shaft upper holding portion 33 and the output shaft lower holding portion 14e) can be more reliably improved.

As shown in fig. 3, the first notch portion 71 and the second notch portion 72 have the same shape when viewed from the axial direction. The first notch portion 71 and the second notch portion 72 are mirror-symmetrical with respect to the virtual straight line VL. As described above, the first notch portion 71 and the second notch portion 72 of the present embodiment are formed by machining. By forming the first notch portion 71 and the second notch portion 72 in mirror symmetry with respect to the virtual straight line VL, the dimensional accuracy on both sides in the circumferential direction with respect to the central axis J1 can be precisely machined to the same degree. This can improve the dimensional accuracy of the first notch portion 71 and the second notch portion 72 on both sides in the circumferential direction with respect to the center axis J1.

The first notch portion 71 and the second notch portion 72 of the present embodiment have the same width portion 73 and the arc portion 74. The width-equal portion 73 is a region extending from the opening of the first cutout portion 71 or the second cutout portion 72 along the virtual straight line VL by the same width, and has a pair of wall surfaces facing each other in the width direction. The arc portion 74 is disposed at the bottom in the depth direction of the first notch portion 71 or the second notch portion 72. The arc portion 74 has a semicircular arc shape when viewed from the axial direction, and connects a pair of wall surfaces of the same width portion 73. The diameter of the circular arc portion 74 is equal to the width of the same width portion 73. The first notch portion 71 and the second notch portion 72 are machined using an end mill having the same diameter as the width dimension of the width portion 73. That is, according to the present embodiment, when machining the first notch portion 71 and the second notch portion 72, the first notch portion 71 and the second notch portion 72 can be formed by moving the spindle of the machine tool along the virtual straight line VL. Therefore, the dimensional accuracy of the first notch portion 71 and the second notch portion 72 in the circumferential direction of the central axis J1 can be improved.

In the present embodiment, a case will be described in which slit-shaped positioning portions (the first notch portion 71 and the second notch portion 72) are provided as the positioning portions of the first case member 12 and the second notch portion 72. However, the positioning portions are not limited to the present embodiment as long as they are provided in the first housing member 12 and the second housing member 14, respectively, and are open to both sides in the axial direction. For example, a through hole penetrating in the axial direction may be used instead of the slit-shaped positioning portion.

Further, as shown in the present embodiment, the jig 9 can be inserted from the notch opening side along the virtual straight line VL by using the first notch portion 71 and the second notch portion 72 as the notch-shaped positioning portions. Therefore, according to the present embodiment, the first housing part 12 and the second housing part 14 can be positioned easily and with high accuracy.

The jig 9 has a tapered shape whose width decreases toward the distal end side along the virtual straight line VL when viewed from the axial direction. The width of the tip of the jig 9 is smaller than the width of the same width portion 73 of the first notch portion 71 and the second notch portion 72. The width of the root of the jig 9 is larger than the width of the same width 73 of the first notch 71 and the second notch 72. In the fixing step, the jig 9 is inserted into the first notch portion 71 and the second notch portion 72 along the virtual straight line VL and is brought into contact with the opening edges of the first notch portion 71 and the second notch portion 72.

According to the present embodiment, the jig 9 is formed in a wedge shape, and thus the jig is inserted along the virtual straight line VL, whereby the first housing member 12 and the second housing member 14 can be easily aligned.

As described above, the first and second cutout portions 71 and 72 of the first and second housing members 12 and 14 of the present embodiment have improved circumferential position accuracy. On the other hand, the first notch portion 71 and the second notch portion 72 are machined by moving a cutting tool such as an end mill along the virtual straight line VL. Therefore, the dimensional accuracy in the depth direction of the first notch portion 71 and the second notch portion 72 is not improved. According to the present embodiment, the jig 9 is in contact with the opening edges of the first and second cut-out portions 71 and 72. Therefore, regardless of the dimensional accuracy in the depth direction of the first notch portion 71 and the second notch portion 72, the first notch portion 71 and the second notch portion 72 can be positioned with high accuracy.

Fig. 4 is a perspective view of the first cut portion 71 and the second cut portion 72 and the jig 9 inserted into them. As shown in fig. 4, the jig 9 preferably has a first jig piece 9a and a second jig piece 9b separated from each other.

The first jig piece 9a and the second jig piece 9b have the same shape. That is, the first jig piece 9a and the second jig piece 9b are tapered such that the width thereof becomes narrower toward the distal end side along the virtual straight line VL. The first jig piece 9a and the second jig piece 9b extend in the axial direction with the same cross-sectional shape. The first jig piece 9a and the second jig piece 9b are stacked in the axial direction.

The first jig piece 9a and the second jig piece 9b are connected to each other. The first jig piece 9a and the second jig piece 9b are allowed to move relatively in the direction along the imaginary straight line VL. On the other hand, the first jig piece 9a and the second jig piece 9b are not allowed to move relatively in directions other than the direction along the virtual straight line VL. That is, the first jig piece 9a and the second jig piece 9b restrict relative movement in a direction perpendicular to the virtual straight line VL.

The first jig piece 9a is disposed to face the first notch portion 71. On the other hand, the second jig piece 9b is disposed to face the second notch portion 72. The boundary surface between the first jig piece 9a and the second jig piece 9b and the boundary surface between the first housing member 12 and the second housing member 14 are arranged on the same plane. The first jig piece 9a is inserted into the first notch portion 71 along the imaginary straight line VL and contacts the opening edge of the first notch portion 71. The second jig piece 9b is inserted into the second cutout portion 72 along the virtual straight line VL, and contacts the opening edge of the second cutout portion 72.

In the present embodiment, the position of the opening edge of the first notch portion 71 and the position of the opening edge of the second notch portion 72 may be offset in the direction along the virtual straight line VL. This is because the outer edge shape of the first housing member 12 provided with the first cutout portion 71 does not necessarily coincide with the outer edge shape of the second housing member 14 provided with the second cutout portion 72.

According to the present embodiment, the first jig piece 9a and the second jig piece 9b can independently operate along the virtual straight line VL. Therefore, even if the positions of the opening edges of the first cutout portion 71 and the second cutout portion 72 are arranged so as to be offset from each other in the direction along the virtual straight line VL, the jig 9 can accurately perform positioning in the circumferential direction.

After the fixing step, a second preliminary step and a lid member fixing step are performed. The second preliminary process is a process of mounting the circuit board 70 and the bus bar unit 90 to the second housing part 14. The lid member fixing step is a step of fixing the lid member 13 to the second housing member 14. The electric actuator 10 is manufactured through the cover member fixing step.

While the embodiments of the present invention have been described above, the configurations and combinations of the embodiments are merely examples, and additions, omissions, substitutions, and other changes in the configurations can be made without departing from the scope of the present invention. In addition, the present invention is not limited by the embodiments.

The electric actuator according to the present invention may be a motor without a speed reduction mechanism as long as it is a device that can move an object to be moved by being supplied with electric power. The electric actuator may be an electric pump including a pump section driven by a motor section. The use of the electric actuator is not particularly limited. The electric actuator may be mounted on an actuator device of a shift-by-wire system that is driven in accordance with a shift operation by a driver. The electric actuator may be mounted on a device other than the vehicle. In addition, the respective structures described in the present specification can be appropriately combined within a range not inconsistent with each other.

Claims (3)

1. An electric actuator, characterized in that,

the electric actuator includes:

a motor unit having a motor shaft that rotates about a central axis;

a transmission mechanism coupled to the motor shaft;

an output shaft that rotates about an output axis parallel to the central axis, and to which power of the motor shaft is transmitted via the transmission mechanism;

a first housing member that rotatably supports the motor shaft and the output shaft from one axial side; and

a second housing part rotatably supporting the motor shaft and the output shaft from the other axial side,

a first positioning portion is provided on the first housing member,

a second positioning portion is provided at the second housing part,

the first housing member and the second housing member are fixed in a state where the first positioning portion and the second positioning portion overlap each other when viewed from the axial direction,

the output shaft is disposed on an imaginary straight line passing through the central axis, the first positioning portion, and the second positioning portion, as viewed in an axial direction.

2. The electric actuator according to claim 1,

the first positioning portion and the second positioning portion are each mirror-symmetrical with respect to the imaginary straight line.

3. The electric actuator according to claim 2,

the first positioning portion has a notch shape extending inward from an outer edge of the first housing member when viewed in an axial direction,

the second positioning portion has a notch shape extending inward from an outer edge of the second housing member when viewed in the axial direction.

Images