Electric Actuator

Abstract

To simplify an assembly step related to a circuit board and a bus bar holder.SOLUTION: An electric actuator comprises: a motor part 20; a bus bar 150; a bus bar holder 140; a circuit board 70; a case 10 that houses the motor part, the bus bar, the bus bar holder, and the circuit board; and a lid member 80. The case has: an inner lateral face that surrounds a stator 23 from the radial outside; and a supporting surface 12 that faces one side in an axial direction, being located at the one side in the axial direction of the inner lateral face. The lid member has: a plate-like lid main body that covers an opening; and a hanging part 83 that extends from the lid main body to the other side in the axial direction. The circuit board and the bus bar holder are sandwiched between a lower end surface of the hanging part and the supporting surface in the axial direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] It is known that an electric actuator contains multiple components inside a case, such as a motor unit having a rotor and a stator, a circuit board, a bus bar, etc. For example, Patent Document 1 discloses a configuration in which multiple components, such as a rotor and a stator constituting a motor unit, a circuit board, a bus bar, etc., are individually assembled inside a case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-5431 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above configuration, it is necessary to assemble each of the components, such as the stator, the circuit board, the bus bars, etc., into the case. This requires time and effort to assemble each component into the case, and also requires a structure for fixing each component to the case, which leads to problems of a complex structure and an increase in the number of components.

[0005] In view of the above circumstances, one object of the present invention is to provide an electric actuator that can easily and reliably fix a circuit board and a bus bar holder to a case, thereby simplifying the assembly process. [Means for solving the problem]

[0006] one aspect of an electric actuator of the present invention comprises a motor section having a rotor rotatable about a central axis extending in the axial direction and a stator surrounding the rotor from the radially outside, a busbar electrically connected to the stator, a busbar holder arranged on one axial side of the motor section and holding the busbar, a circuit board arranged on one axial side of the busbar holder along a plane perpendicular to the central axis and electrically connected to the busbar, a case having an opening that opens to one axial side and accommodating the motor section, the busbar, the busbar holder, and the circuit board, and a lid member covering the opening and fixed to the case, the case having an inner side that surrounds the stator from the radial outside, and a support surface located on one axial side of the inner side and facing one axial side, the lid member having a plate-shaped lid main body covering the opening, and a hanging portion extending from the lid main body to the other axial side, the circuit board and the busbar holder being sandwiched in the axial direction between a lower end surface of the hanging portion and the support surface. Effect of the Invention

[0007] According to one aspect of the present invention, in an electric actuator, a circuit board and a bus bar holder can be easily and reliably fixed to a case, thereby simplifying the assembly process. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing an electric actuator of the present embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing a fixing structure of a circuit board and a bus bar holder to a case in an electric actuator according to a first modified example of the present embodiment. [Diagram 3] FIG. 3 is a cross-sectional view showing a fixing structure of a circuit board and a bus bar holder to a case in an electric actuator according to a second modified example of the present embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing a fixing structure of a circuit board and a bus bar holder to a case in an electric actuator according to a third modified example of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an electric actuator according to an embodiment of the present invention will be described with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiment, and can be modified as desired within the scope of the technical concept of the present invention. In addition, in the following drawings, the scale and number of each structure may differ from the actual structure in order to make each configuration easier to understand.

[0010] In each figure, the Z-axis direction is the up-down direction with the positive side at the top and the negative side at 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 be simply referred to as the "axial direction." Furthermore, unless otherwise specified, the radial direction centered on the central axis J1 will be simply referred to as the "radial direction," and the circumferential direction centered on the central axis J1 will be simply referred to as the "circumferential direction."

[0011] In this embodiment, the upper side corresponds to one axial side, and the lower side corresponds to the other 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] The electric actuator 1 of this embodiment shown in Fig. 1 is, for example, an electric actuator mounted on a vehicle. As shown in Fig. 1, the electric actuator 1 includes a case 10, a partition member 15, a cover member 80, a motor section 20 having a motor shaft 21 that rotates around a central axis J1, a first bearing 53, a second bearing 51, a third bearing 52, a reduction gear mechanism 30, an output shaft 41, a magnetic sensor 63, a circuit board 70, a bus bar holder 140, and a bus bar 150.

[0013] Case 10 accommodates partition member 15, motor section 20, motor shaft 21, speed reduction mechanism 30, output shaft 41, magnetic sensor 63, circuit board 70, bus bar holder 140, and bus bar 150. Case 10 has an opening that opens to the upper side.

[0014] The case 10 is cylindrical and extends in the axial direction about the central axis J1. The case 10 has a board accommodating section 13a, a case tube section 13b, an output section accommodating section 13c, and a bearing holding section 13d. The board accommodating section 13a is a section that accommodates the circuit board 70 and the bus bar holder 140. The board accommodating section 13a opens to the upper side. That is, the case 10 has an opening 10a that opens to one axial side. The board accommodating section 13a is configured on the radially inner side of the upper part of the case 10. The bottom surface of the board accommodating section 13a is a support surface 12 that supports and fixes the circuit board 70 and the bus bar holder 140. The support surface 12 faces upward.

[0015] The case cylindrical portion 13b surrounds the radial outside of the motor portion 20. The output portion accommodating portion 13c is a portion that accommodates the output portion 46 described below. The bearing holding portion 13d holds a second bearing 51. The bearing holding portion 13d extends upward from the lower end portion of the case 10 around the central axis J1.

[0016] The lid member 80 covers the opening 10a of the case 10 and is fixed to the case 10. The lid member 80 has a plate-shaped lid main body 81 that covers the opening 10a and a hanging part 83 that extends from the lid main body 81 to the other axial side. The hanging part 83 is provided in a cylindrical shape extending in the axial direction. The lid member 80 is a container-shaped member having a recess 16a that opens downward on the radial inner side of the hanging part 83. The lid member 80 and the case 10 are fastened by a plurality of bolts that pass through the lid member 80 in the axial direction. The lid member 80 has a bearing holding part 16b. The bearing holding part 16b holds the first bearing 53. The bearing holding part 16b extends downward with the central axis J1 as the center.

[0017] The motor unit 20 has a central axis J1. As shown in Fig. 1, the motor unit 20 has a rotor 22 and a stator 23. The rotor 22 has a motor shaft 21, a rotor core 22a, and a magnet 40.

[0018] The motor shaft 21 includes a first shaft portion 21a, a second shaft portion 21b, and a through hole 25. The first shaft portion 21a extends in the axial direction and is located on the upper side of the motor shaft 21. The second shaft portion 21b extends in the axial direction and is located on the lower side of the motor shaft 21. The diameter of the second shaft portion 21b is larger than the diameter of the first shaft portion 21a. More specifically, the outer diameter of the second shaft portion 21b is larger than the outer diameter of the first shaft portion 21a. The second shaft portion 21b is an eccentric shaft portion centered on an eccentric axis J2 that is eccentric with respect to the central axis J1. The eccentric axis J2 is parallel to the central axis J1. The through hole 25 extends around the central axis J1. Therefore, the first shaft portion 21a is cylindrical and extends around the central axis J1. The second shaft portion 21b has an axial recess 26 on the lower side. The recessed portion 26 extends about the eccentric axis J2. Therefore, the second shaft portion 21b is cylindrical and extends about the eccentric axis J2. The upper side of the recessed portion 26 is connected to the lower side of the through hole 25. The second shaft portion 21b of the motor shaft 21 is supported by the third bearing 52 so as to be rotatable about the eccentric axis J2.

[0019] The output shaft 41 receives the rotation of the motor shaft 21 via the reduction gear mechanism 30. The output shaft 41 has a shaft portion 41a and a connecting portion 42. The shaft portion 41a is located on the upper side, and the connecting portion 42 is located on the lower side. The shaft portion 41a is cylindrical and extends around the central axis J1. The upper side of the shaft portion 41a is inserted through the through hole 25 of the motor shaft 21. The upper end of the shaft portion 41a protrudes upward from the motor shaft 21. The upper end of the shaft portion 41a protruding upward from the motor shaft 21 is supported by a first bearing 53 so as to be rotatable around the central axis J1. The upper end of the motor shaft 21 is supported by the cover member 80 via the first bearing 53.

[0020] The lower end of the connecting portion 42 protrudes downward from the motor shaft 21. The lower end of the connecting portion 42 protruding downward from the motor shaft 21 is supported by the second bearing 51 so as to be rotatable around the central axis J1. The lower end of the motor shaft 21 is supported by the case 10 via the second bearing 51. The axial end of the output shaft 41 is supported by the first bearing 53 and the second bearing 51 so as to be rotatable around the central axis J1. Therefore, the motor shaft 21, in which the shaft portion 41a of the output shaft 41 is passed through the through hole 25, is supported by the shaft portion 41a so as to be rotatable around the central axis J1.

[0021] The first bearing 53, the second bearing 51, and the third bearing 52 are each a rolling bearing having an inner ring and an outer ring located radially outside the inner ring. In this embodiment, the first bearing 53, the second bearing 51, and the third bearing 52 are, for example, ball bearings in which the inner ring and the outer ring are connected via a plurality of balls.

[0022] The upper side of the connecting part 42 is inserted into the recessed part 26 of the motor shaft 21. By inserting the upper side of the connecting part 42 into the recessed part 26 of the motor shaft 21, the axial length of the output shaft 41 can be shortened. Therefore, the axial length of the electric actuator 1 can be shortened, and the size can be reduced.

[0023] The connecting portion 42 has a cylindrical tube portion 44 extending about the central axis J1. A connecting recess 45 is provided on the inner diameter of the tube portion 44. The connecting recess 45 is recessed upward from the lower end of the output shaft 41. When viewed along the axial direction, the connecting recess 45 has a substantially circular shape centered on the central axis J1. A plurality of spline grooves are provided on the inner peripheral surface of the connecting recess 45 along the circumferential direction. Another member to which the driving force of the electric actuator 1 is output is inserted and connected to the connecting recess 45. The other member is, for example, a manual shaft in a vehicle. The electric actuator 1 drives the manual shaft based on a shift operation by the driver to switch the gears of the vehicle.

[0024] By having the connecting portion 42 have the connecting recess 45 recessed upward, the axial length of the output shaft 41 can be shortened compared to when the connecting portion 42 is axially projecting downward. Therefore, the axial length of the electric actuator 1 can be shortened and made compact. The first bearing 53 is held by the bearing holder 16b provided on the case 10, and the second bearing 51 is held by the bearing holder 13d provided on the case 10, so that the concentricity of the output shaft 41 with respect to the central axis J1 can be improved. The first bearing 53 is held by the bearing holder 16b provided on the case 10, and the second bearing 51 is held by the bearing holder 13d provided on the case 10, so that it is not necessary to provide separate holders for the first bearing 53 and the second bearing 51, which contributes to cost reduction and compactness of the electric actuator 1.

[0025] The rotor core 22a is fixed to an outer circumferential surface of the motor shaft 21. More specifically, the rotor core 22a is fixed to an outer circumferential surface of the first shaft portion 21a. The magnet 40 is fixed to the radially outer side of the rotor core 22a. A plurality of magnets 40 are arranged at intervals in the circumferential direction.

[0026] The stator 23 is located radially outside the rotor 22. The stator 23 has a stator core 23a, a plurality of coils 23b, and an insulator 29. The stator core 23a is annular and surrounds the radial outside of the rotor 22. An outer core surface 24a of the stator core 23a is fixed to the inner surface 14 of the case cylindrical portion 13b. In other words, the inner surface 14 of the case 10 surrounds the stator 23 from the radial outside. The coils 23b are attached to the teeth of the stator core 23a via insulators 29.

[0027] The partition member 15 is disposed on the other axial side of the motor section 20. The partition member 15 is disposed axially between the stator 23 and the reduction mechanism 30. The partition member 15 is in the shape of an annular plate. The partition member 15 supports the stator core 23a from below. The outer periphery of the partition member 15 contacts the step portion 11 of the case 10 from one axial side. The step portion 11 is located on the other axial side of the inner surface 14. The step portion 11 faces one axial side.

[0028] The busbar holder 140 is disposed above the rotor 22. The busbar holder 140 is disposed on one axial side of the motor section 20. The busbar holder 140 is in the shape of an annular plate. The busbar holder 140 has a holder body 148 and a nut member 143. The holder body 148 is made of an insulating resin material. The holder body 148 of the busbar holder 140 has a flange portion 140f that extends radially outward from a cylindrical portion 141 described later. The flange portion 140f of the busbar holder 140 contacts a support surface 12 of the case 10 from one axial side. The support surface 12 is located on one axial side of the inner surface 14. The support surface 12 faces one axial side.

[0029] The nut member 143 has a cylindrical shape extending in the axial direction. The nut member 143 is provided with a screw hole 143a penetrating in the axial direction. The nut member 143 is embedded in the flange portion 140f of the holder main body 148 in an orientation along the axial direction. That is, the bus bar holder 140 is provided with a screw hole 143a penetrating in the axial direction. The nut member 143 protrudes to the upper side of the bus bar holder 140. An end face 143f on one axial side of the nut member 143 contacts the lower side of the circuit board 70. An end face 143g on the other axial side of the nut member 143 contacts the support surface 12. As a result, the bus bar holder 140 is sandwiched between the circuit board 70 and the support surface 12 in the axial direction.

[0030] The support surface 12 is provided with a positioning hole 12a at a position axially communicating with the screw hole 143a of the nut member 143. The positioning hole 12a opens on one axial side of the support surface 12.

[0031] The bus bar holder 140 has a cylindrical portion 141 extending downward. The cylindrical portion 141 is located radially outward from the insulator 29 of the stator 23. The cylindrical portion 141 surrounds the insulator 29 of the stator 23. The cylindrical portion 141 is located radially inward from the core outer peripheral surface 24a of the stator 23. A lower end of the cylindrical portion 141 contacts an upper side of the stator 23. As the lower end of the cylindrical portion 141 contacts an upper side of the stator 23, the stator 23 is sandwiched between the bus bar holder 140 and the partition member 15 in the axial direction.

[0032] Holder body 148 holds magnetic sensor 63, conductive wire 64, and multiple bus bars 150. In this embodiment, holder body 148, magnetic sensor 63, conductive wire 64, nut member 143, and multiple bus bars 150 are resin-molded into an integrated molded body. More specifically, bus bar holder 140 is produced by insert molding using magnetic sensor 63, conductive wire 64, nut member 143, and bus bars 150 as insert members.

[0033] The magnetic sensor 63 can detect the magnetic field of the magnet 40. The magnetic sensor 63 is, for example, a Hall element. The magnetic sensor 63 is held by a magnetic sensor holding portion 145 of the bus bar holder 140. The magnetic sensor holding portion 145 is provided on the lower surface of the bus bar holder 140. The magnetic sensor holding portion 145 is recessed from the lower surface of the bus bar holder 140 to one axial side. The magnetic sensor 63 is fixed to the bus bar holder 140 by being inserted into the magnetic sensor holding portion 145. The magnetic sensor 63 is disposed on the upper side of the magnet, facing each other with a gap therebetween. Three magnetic sensors 63 are disposed at intervals in the circumferential direction. The circumferential interval between the magnetic sensors 63 is the same as the circumferential interval between the magnetic poles. The magnetic sensor 63 detects the magnetic field of the magnet 40 to detect the rotational position of the magnet 40 and detect the rotation of the motor shaft 21.

[0034] One end of the conductive wire 64 is electrically connected to the magnetic sensor 63. The conductive wire 64 may be a terminal extending from the magnetic sensor 63, or may be a bus bar having one end connected to the magnetic sensor 63. The conductive wire 64 passes through the bus bar holder 140 from inside the bus bar holder 140, and the other end is electrically connected to the circuit board 70 by a connection method such as soldering, welding, or press fitting.

[0035] One end of the bus bar 150 is electrically connected to the stator 23. The other end of the bus bar 150 is electrically connected to the circuit board 70.

[0036] The circuit board 70 is disposed on one axial side of the bus bar holder 140. The circuit board 70 is plate-shaped and extends in a plane perpendicular to the axial direction. The circuit board 70 is accommodated in the case 10. More specifically, the circuit board 70 is accommodated in the board accommodating portion 13a. The circuit board 70 is a board electrically connected to the motor section 20. The circuit board 70 controls, for example, the current supplied to the motor section 20. That is, the circuit board 70 is equipped with, for example, an inverter circuit. The circuit board 70 is electrically connected to the motor section 20 via the bus bar 150.

[0037] The circuit board 70 is provided with a fixing hole 70a penetrating in the axial direction. The circuit board 70 is fixed to the bus bar holder 140 by a positioning screw 144. The bus bar holder 140 and the circuit board 70 are connected by the positioning screw 144 from above at a position overlapping with the positioning hole 12a when viewed in the axial direction. For example, four positioning screws 144 are provided. The positioning screw 144 integrally has a head 144a, a threaded portion 144b extending from the head 144a to the other axial side, and a positioning pin portion 144c located at the tip of the threaded portion 144b. The positioning screw 144 is fastened to the threaded hole 143a through the fixing hole 70a from one axial side. The screwed circuit board 70 is disposed above the bus bar holder 140 with a gap therebetween. The dimension of the gap between the circuit board 70 and the bus bar holder 140 is such that the nut member 143 protrudes upward from the bus bar holder 140 .

[0038] Furthermore, positioning pin portion 144c of positioning screw 144 protrudes further axially to the other side than end face 143g of nut member 143, and is inserted into positioning hole 12a, thereby restricting circumferential movement of circuit board 70 and bus bar holder 140.

[0039] Circuit board 70 and bus bar holder 140 fastened by set screws 144 are sandwiched in the axial direction between the lower end surface of hanging portion 83 and support surface 12. This causes circuit board 70 and bus bar holder 140 to be fixed in the axial direction.

[0040] The reduction mechanism 30 is connected to the rotor 22 on the other axial side of the motor unit 20. The reduction mechanism 30 reduces the power of the rotor 22. The reduction mechanism 30 is disposed radially outside the second shaft portion 21b of the motor shaft 21 and radially outside the connecting portion 42 of the output shaft 41. The reduction mechanism 30 is disposed below the motor unit 20. The reduction mechanism 30 has an external gear 31, an internal gear 32, an output portion 46, and a plurality of protrusions 43.

[0041] The external gear 31 is annular and extends radially about the eccentric shaft J2 of the second shaft portion 21b. A gear portion is provided on the radially outer surface of the external gear 31. The gear portion of the external gear 31 has a plurality of teeth arranged along the outer periphery of the external gear 31.

[0042] The external gear 31 is connected to the motor shaft 21. More specifically, the external gear 31 is connected to the second shaft portion 21b of the motor shaft 21 via the third bearing 52. As a result, the motor shaft 21 is connected to the reduction gear mechanism 30. The external gear 31 is fitted into the outer ring of the third bearing 52 from the outside in the radial direction. The second shaft portion 21b is fitted into the inner ring of the third bearing 52 from the outside in the radial direction. As a result, the third bearing 52 connects the motor shaft 21 and the external gear 31 to be relatively rotatable around the eccentric axis J2.

[0043] In this embodiment, the external gear 31 has a plurality of holes 31a. In this embodiment, the holes 31a penetrate the external gear 31 in the axial direction. The plurality of holes 31a are arranged along the circumferential direction. More specifically, the plurality of holes 31a are arranged at equal intervals around one circumference along the circumferential direction centered on the eccentric axis J2. The holes 31a are circular when viewed in the axial direction. The inner diameter of the hole 31a is larger than the outer diameter of the protrusion 43. The hole 31a may be a hole having a bottom.

[0044] The internal gear 32 is located radially outside the external gear 31 and is annular in shape surrounding the external gear 31. In this embodiment, the internal gear 32 is annular in shape centered on the central axis J1. The radial outer edge of the internal gear 32 is disposed and fixed to a step portion 13e recessed radially inwardly on the inner circumferential surface of the case tube portion 13b. This allows the reduction mechanism 30 to be held in the case 10. The internal gear 32 meshes with the external gear 31. A gear portion is provided on the radial inner side surface of the internal gear 32. The gear portion of the internal gear 32 has a plurality of teeth portions arranged along the inner circumference of the internal gear 32. In this embodiment, the gear portion of the internal gear 32 meshes with the gear portion of the external gear 31 only in a portion of the circumferential direction.

[0045] The output portion 46 has an annular plate shape that expands in the radial direction about the central axis J1. The output portion 46 is located below the external gear 31. The output portion 46 is fixed to the outer circumferential surface of the output shaft 41. More specifically, the output portion 46 is fixed to the outer circumferential surface of the connecting portion 42 of the output shaft 41.

[0046] The multiple protrusions 43 are fixed to the output portion 46 by, for example, welding. The multiple protrusions 43 protrude upward from the output portion 46. That is, the multiple protrusions 43 protrude from the output portion 46 toward the external gear 31. The protrusions 43 are cylindrical. 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.

[0047] The multiple protrusions 43 are inserted into the multiple hole portions 31a, respectively. The outer peripheral surface of the protrusion 43 is inscribed in the inner peripheral surface of the hole portion 31a. As a result, the multiple protrusions 43 support the external gear 31 via the inner surface of the hole portion 31a so as to be swingable around the central axis J1.

[0048] In this embodiment, the hole 31a and the protrusion 43 overlap with the third bearing 52 and the second shaft portion 21b when viewed in the radial direction. In other words, the hole 31a, the protrusion 43, the third bearing 52, and the second shaft portion 21b each have a portion located at the same position as each other in the axial direction.

[0049] When the motor shaft 21 rotates around the central axis J1, the second shaft portion 21b, which is an eccentric shaft portion, revolves in the circumferential direction around the central axis J1. The revolution of the second shaft portion 21b is transmitted to the external gear 31 via the third bearing 52, and the external gear 31 oscillates while changing the position where the inner circumferential surface of the hole portion 31a and the outer circumferential 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.

[0050] Here, in this embodiment, the internal gear 32 is fixed and does not rotate. 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 output portion 46 via the hole portion 31a 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 via the reduction mechanism 30.

[0051] The rotation of the output shaft 41 is reduced relative to the rotation of the motor shaft 21 by the reduction gear mechanism 30. Specifically, in the configuration of the reduction gear mechanism 30 of this embodiment, the reduction ratio R of the rotation of the output shaft 41 to the rotation of the motor shaft 21 is expressed as R=-(N2-N1) / N2. The negative sign at the beginning of the equation expressing the reduction ratio R indicates that the rotation direction of the output shaft 41, which is reduced, is opposite to the rotation direction of the motor shaft 21. N1 is the number of teeth of the external gear 31, and N2 is the number of teeth of the internal gear 32. As an example, when the number of teeth N1 of the external gear 31 is 59 and the number of teeth N2 of the internal gear 32 is 60, the reduction ratio R is -1 / 60.

[0052] Thus, according to electric actuator 1 of the present embodiment, circuit board 70 and bus bar holder 140 are sandwiched in the axial direction between the lower end surface of hanging portion 83 and support surface 12. This allows circuit board 70 and bus bar holder 140 to be fixed in the axial direction to case 10 by attaching cover member 80 to case 10. Therefore, circuit board 70 and bus bar holder 140 can be easily and reliably fixed to case 10, simplifying the assembly process.

[0053] According to this embodiment, the circuit board 70, the bus bar holder 140, and the case 10 can be positioned relative to each other in the circumferential direction by inserting the positioning pin portion 144c of the positioning screw 144 into the positioning hole 12a. In addition, the circuit board 70 and the bus bar holder 140 can be fixed to each other by the positioning screw 144 to form a sub-assembly. This improves the handleability of the parts in the assembly process of the electric actuator 1.

[0054] According to this embodiment, a gap can be provided between the circuit board 70 and the holder body 148 by the nut member 143 embedded in the holder body 148. This makes it easy to mount components on the other axial surface of the circuit board 70. In addition, creep of the holder body 148 caused by fastening pressure can be suppressed.

[0055] According to this embodiment, since bus bar holder 140 has magnetic sensor holding portion 145, magnetic sensor 63 can be attached easily and with high accuracy.

[0056] According to the present embodiment, in the electric actuator 1 having the speed reduction mechanism 30, the circuit board 70 and the bus bar holder 140 can be easily and reliably fixed to the case 10, simplifying the assembly process.

[0057] (First Modification) 2 is a cross-sectional view showing a fixing structure of a circuit board and a bus bar holder to a case in an electric actuator according to a modification of the above-described embodiment. Electric actuator 1B of this modification differs from the above-described electric actuator 1 mainly in the fixing structure of circuit board 170 and bus bar holder 190 to case 110. Note that the same components as those in the above-described embodiment are given the same reference numerals and their description will be omitted.

[0058] As shown in Fig. 2, the electric actuator 1B in this modified example mainly includes a case 110, a cover member 180, a motor section 20, a circuit board 170, and a bus bar holder 190. The case 110 has a board accommodating section 113a (opening 110a) that opens to one axial side. The board accommodating section 113a is configured on the radially inner side of the upper part of the case 110. The bottom surface of the board accommodating section 113a is a support surface 112 that supports and fixes the circuit board 170 and the bus bar holder 190. The support surface 112 faces upward.

[0059] In electric actuator 1B of this modified example, lid member 180 covers opening 110a of case 110 and is fixed to case 110. Lid member 180 has a plate-shaped lid main body 181 that covers opening 110a, and a hanging portion 183 that extends to the other axial side from lid main body 181. Lid member 180 and case 110 are fastened together by a plurality of bolts that pass through lid member 180 in the axial direction.

[0060] In the electric actuator 1B of this modified example, the bus bar holder 190 has a holder body 198 and a collar member 193. The holder body 198 is made of an insulating resin material. The holder body 198 of the bus bar holder 190 has a flange portion 190f that extends radially outward. The flange portion 190f of the bus bar holder 190 contacts the support surface 112 of the case 110 from one axial side. The support surface 112 faces one axial side. The collar member 193 is provided with a positioning hole 193a that penetrates in the axial direction. The collar member 193 is embedded in the flange portion 190f of the holder body 198 in a position along the axial direction. An end face 193f of the collar member 193 on one axial side contacts the lower side of the circuit board 170. An end face 193g of the collar member 193 on the other axial side contacts the support surface 112.

[0061] In the electric actuator 1B of this modified example, a positioning hole 170a penetrating in the axial direction is provided in a circuit board 170. The positioning hole 170a is provided so as to overlap with the positioning hole 193a when viewed in the axial direction. A positioning pin portion 112a protruding to one axial direction is provided on the support surface 112. The positioning pin portion 112a is inserted into positioning holes 170a, 193a of the circuit board 70 and the bus bar holder 140.

[0062] According to this modified example, similarly to the above-described embodiment, circuit board 170 and bus bar holder 190 are sandwiched in the axial direction between the lower end surface of hanging portion 183 and support surface 112, thereby enabling circuit board 170 and bus bar holder 190 to be easily and reliably fixed to case 110 and simplifying the assembly process.

[0063] According to this modification, by inserting positioning pin portions 112a into positioning holes 170a, 193a of circuit board 170 and bus bar holder 190, circuit board 170, bus bar holder 190, and case 110 can be positioned relative to each other in the circumferential direction.

[0064] (Second Modification) 3 is a cross-sectional view showing a fixing structure of a circuit board and a bus bar holder to a case in an electric actuator according to a modification of the above-described embodiment. Electric actuator 1C of this modification differs from electric actuator 1 described above mainly in the fixing structure of circuit board 270 and bus bar holder 290 to case 210. Note that the same components as those in the above-described embodiment are given the same reference numerals and their description will be omitted.

[0065] As shown in Fig. 3, the electric actuator 1C in this modified example mainly includes a case 210, a cover member 280, a motor section 20, a circuit board 270, and a bus bar holder 290. The case 210 has a board accommodating section 213a (opening 210a) that opens to one axial side. The bottom surface of the board accommodating section 213a is a support surface 212 that supports and fixes the circuit board 270 and the bus bar holder 290. The support surface 212 faces upward. A positioning hole 212a is provided in the support surface 212. The positioning hole 212a opens to one axial side.

[0066] In electric actuator 1C of this modified example, lid member 280 covers opening 210a of case 210 and is fixed to case 210. Lid member 280 has a plate-shaped lid main body 281 that covers opening 210a, and a hanging portion 283 that extends to the other axial side from lid main body 281. Lid member 280 and case 210 are fastened together by a plurality of bolts that pass through lid member 280 in the axial direction.

[0067] In the electric actuator 1C of this modified example, a circuit board 270 is provided with a positioning hole 270a that penetrates therethrough in the axial direction.

[0068] In the electric actuator 1C of this modification, the bus bar holder 290 has a holder body 298, a first positioning pin portion 290a, and a second positioning pin portion 290b. The holder body 298 is made of an insulating resin material. The holder body 298 of the bus bar holder 290 has a flange portion 290f that expands radially outward. The flange portion 290f of the bus bar holder 290 contacts the support surface 212 of the case 210 from one axial side. The first positioning pin portion 290a protrudes from the flange portion 290f to one axial side. An expanded diameter portion 290c that expands radially outward is provided on the other axial side (holder body 298) of the first positioning pin portion 290a. A step surface 292 facing one axial side is provided between the expanded diameter portion 290c and the first positioning pin portion 290a. The first positioning pin portion 290a is inserted into the positioning hole 270a of the circuit board 270. With the first positioning pin portion 290a inserted into the positioning hole 270a, the step surface 292 contacts the underside of the circuit board 270. The second positioning pin portion 290b protrudes from the flange portion 290f to the other axial side. The second positioning pin portion 290b is inserted into the positioning hole 212a of the support surface 212.

[0069] According to this modification, similarly to the above-described embodiment, circuit board 270 and bus bar holder 290 are sandwiched in the axial direction between the lower end surface of hanging portion 283 and support surface 212, thereby enabling circuit board 270 and bus bar holder 290 to be easily and reliably fixed to case 210 and simplifying the assembly process.

[0070] According to this modification, by inserting first positioning pin portion 290a and second positioning pin portion 290b into positioning holes 270a, circuit board 270, bus bar holder 290, and case 210 can be positioned relative to each other in the circumferential direction.

[0071] (Third Modification) 4 is a cross-sectional view showing the fixing structure of the circuit board and bus bar holder to the case in an electric actuator according to a modification of the above-mentioned embodiment. Electric actuator 1D of this modification differs from the above-mentioned electric actuator 1 mainly in the fixing structure of circuit board 370 and bus bar holder 390 to case 310. Note that the same components as those in the above-mentioned embodiment are given the same reference numerals and their description will be omitted.

[0072] As shown in Fig. 4, the electric actuator 1D in this modified example mainly includes a case 310, a cover member 380, a motor section 20, a circuit board 370, and a bus bar holder 390. The case 310 has a board accommodating section 313a (opening 310a) that opens to one axial side. The bottom surface of the board accommodating section 313a is a support surface 312 that supports and fixes the circuit board 370 and the bus bar holder 390. The support surface 312 faces upward. A positioning hole 312a is provided in the support surface 312. The positioning hole 312a opens to one axial side.

[0073] In electric actuator 1D of this modified example, lid member 380 covers opening 310a of case 310 and is fixed to case 310. Lid member 380 has a plate-shaped lid main body 381 that covers opening 310a, and a hanging portion 383 that extends to the other axial side from lid main body 381. Lid member 380 and case 310 are fastened together by a plurality of bolts that pass through lid member 380 in the axial direction.

[0074] In the electric actuator 1D of this modification, the bus bar holder 390 has a holder body 398 and a collar member 393. The holder body 398 is made of an insulating resin material. The holder body 398 of the bus bar holder 390 has a flange portion 390f that extends radially outward. The flange portion 390f of the bus bar holder 390 contacts the support surface 312 of the case 310 from one axial side. The collar member 393 is provided with a positioning hole 393a that penetrates in the axial direction. The collar member 393 is embedded in the flange portion 390f of the holder body 398 in a position along the axial direction. An end face 393f on one axial side of the collar member 393 contacts the lower side of the circuit board 370. An end face 393g on the other axial side of the collar member 393 contacts the support surface 312.

[0075] In the electric actuator 1D of this modified example, a positioning hole 370a penetrating in the axial direction is provided in a circuit board 370. The positioning holes 312a, 370a, 393a are provided so as to overlap one another when viewed in the axial direction.

[0076] Positioning pin portion 383a is provided on the lower end surface of hanging portion 383. Positioning pin portion 383a protrudes to the other axial direction side from the lower end surface of hanging portion 383. Positioning pin portion 383a is inserted into positioning holes 312a, 370a, 393a of circuit board 70, bus bar holder 140, and support surface 12.

[0077] According to this modification, similarly to the above-described embodiment, circuit board 370 and bus bar holder 390 are sandwiched in the axial direction between the lower end surface of hanging portion 383 and support surface 312, thereby enabling circuit board 370 and bus bar holder 390 to be easily and reliably fixed to case 310 and simplifying the assembly process.

[0078] According to this modification, by inserting positioning pin portion 383a into positioning holes 312a, 370a, 393a, circuit board 370, bus bar holder 390, case 310, and cover member 380 can be positioned relative to one another in the circumferential direction.

[0079] Although one embodiment of the present invention has been described above, each configuration and their combination in the embodiment is merely an example, and addition, omission, substitution, and other modifications of the configuration are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiment.

[0080] For example, the electric actuator to which the present invention is applied may be a device capable of moving a target object by supplying electric power, and may be a motor without a reduction mechanism. The electric actuator may also be an electric pump equipped with 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 a shift-by-wire type actuator device that is driven based on the driver's shift operation. The electric actuator may also be mounted on equipment other than a vehicle. Note that the configurations described in this specification may be appropriately combined within a range that does not contradict each other. [Explanation of symbols]

[0081] 1, 1B, 1C, 1D... Electric actuator, 10, 110, 210, 310... Case, 10a, 110a, 210a, 310a... Opening, 12, 112, 212, 312... Support surface, 12a... Positioning hole, 14... Inner surface, 20... Motor part, 22... Rotor, 23... Stator, 30... Reduction mechanism, 40... Magnet, 63... Magnetic sensor, 70, 170, 270, 370... Circuit board, 70a... Fixing hole, 80, 180, 280, 380... Lid member, 81, 181, 281, 381... Lid main body, 83, 183, 283, 383... Hanging part, 112a... Positioning pin part, 140, 190, 290, 390...busbar holder, 143...nut member, 143a...screw hole, 143f...end face, 143g...end face, 144...positioning screw, 144a...head, 144b...screw portion, 144c...positioning pin portion, 145...magnetic sensor holding portion, 148, 198, 298, 398...holder body, 150...busbar, 170a, 193a...positioning hole, 212a, 270a...positioning hole, 290a...first positioning pin portion, 290b...second positioning pin portion, 312a, 370a, 393a...positioning hole, 383a...positioning pin portion, J1...center axis

Claims

1. a motor section including a rotor rotatable about a central axis extending in an axial direction and a stator surrounding the rotor from the radially outer side; A bus bar electrically connected to the stator; a bus bar holder arranged on one axial side of the motor unit and holding the bus bar; a circuit board disposed on one axial side of the bus bar holder along a plane perpendicular to the central axis and electrically connected to the bus bar; a case having an opening that opens to one axial side and that houses the motor unit, the bus bars, the bus bar holder, and the circuit board; a cover member that covers the opening and is fixed to the case; a plurality of bolts for fastening the cover member and the case; Equipped with The case is An inner surface surrounding the stator from a radially outer side; A support surface is located on one axial side of the inner surface and faces the one axial side, The cover member is A plate-shaped lid body that covers the opening; A hanging portion extending from the lid body to the other axial direction, the circuit board and the bus bar holder are axially sandwiched between a lower end surface of the hanging portion and the support surface, the circuit board and the bus bar holder are not fastened to the case; Electric actuator.

2. a set screw having a head, a threaded portion extending from the head to the other axial direction, and a set screw having a set pin portion located at a tip of the threaded portion; The circuit board is provided with a fixing hole passing through in an axial direction, The bus bar holder is provided with a screw hole passing therethrough in an axial direction, The support surface is provided with a positioning hole that opens to one side in the axial direction, The positioning screw is fastened to the screw hole through the fixing hole from one axial side, and the positioning pin portion is inserted into the positioning hole. The electric actuator according to claim 1 .

3. The bus bar holder includes: A holder body made of a resin material; a nut member having the screw hole and embedded in the holder body, the bus bar holder is in contact with the circuit board at an end surface on one axial side of the nut member, and in contact with the support surface at an end surface on the other axial side of the nut member. The electric actuator according to claim 2.

4. the circuit board and the bus bar holder are provided with positioning holes that overlap each other when viewed in the axial direction; a positioning pin portion protruding toward one axial direction side and inserted into the positioning holes of the circuit board and the bus bar holder is provided on the support surface; The electric actuator according to claim 1 .

5. The circuit board and the support surface are each provided with a positioning hole, The bus bar holder includes: a first positioning pin portion that protrudes to one side in the axial direction and is inserted into the positioning hole of the circuit board; a second positioning pin portion protruding to the other axial side and inserted into the positioning hole of the support surface; The electric actuator according to claim 1 .

6. the circuit board, the bus bar holder, and the support surface are provided with positioning holes that overlap with each other when viewed in the axial direction; a positioning pin portion protruding toward the other axial direction is provided on a lower end surface of the hanging portion and inserted into the positioning holes of the circuit board, the bus bar holder, and the support surface; The electric actuator according to claim 1 .

7. a magnetic sensor for detecting a magnetic field of a magnet of the rotor; The bus bar holder has a magnetic sensor holding portion that holds the magnetic sensor. The electric actuator according to any one of claims 1 to 6.

8. a reduction mechanism connected to the rotor on the other axial side of the motor unit to reduce the power of the rotor; The case accommodates the reduction mechanism. The electric actuator according to any one of claims 1 to 7.

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