Electric actuator

Abstract

The utility model provides an electric actuator which is provided with a first shaft, a second shaft and a transmission mechanism. The transmission mechanism includes: a first gear rotatable about a first axis; a second gear that is rotatable about a second axis and meshes with the first gear; a third gear that is rotatable about the second axis and is disposed on one side in the axial direction of the second gear; a fourth gear that is rotatable about the first axis and meshes with the third gear; a fifth gear that is rotatable about the first axis and is disposed on one side in the axial direction of the fourth gear; and a sixth gear that is rotatable about the second axis and meshes with the fifth gear. The outer diameter of the second gear is larger than that of the first gear, the outer diameter of the fourth gear is larger than that of the third gear, the outer diameter of the sixth gear is larger than that of the fifth gear, the axial size of the second gear is smaller than that of the fourth gear, and the axial size of the fourth gear is smaller than that of the sixth gear.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of electric actuators. BACKGROUND

[0002] It is known that the actuator (for example, patent document 1) reduces and transmits the rotation of the motor shaft possessed by the motor to the transmission shaft by the reduction mechanism having a plurality of gears.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent document 1: Japanese patent application publication No. 2007-270798 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE UTILITY MODEL

[0007] In the actuator as described above, since the plurality of gears possessed by the reduction mechanism are arranged in the radial direction with the motor shaft as the center, it is difficult to suppress the reduction mechanism from being large in the radial direction. Therefore, it is difficult to suppress the actuator from being large in the radial direction.

[0008] The utility model in view of the above situation, one of its purposes is to provide a kind of electric actuator capable of inhibiting transmission mechanism large.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] The electric actuator according to the present application is characterized by comprising: a motor unit; a first shaft that transmits rotation of a rotor included in the motor unit and is rotatable about a first axis; a second shaft that is rotatable about a second axis and is disposed apart from the first shaft in a radial direction about the first axis, the second axis extending in the same direction as an axial direction of the first axis; and a transmission mechanism that transmits rotation of the first shaft to the second shaft, the transmission mechanism including: a first gear that is rotatable about the first axis; a second gear that is rotatable about the second axis and is engaged with the first gear; a third gear that is rotatable about the second axis, is disposed on a side of the second gear in the axial direction, and is connected to the second gear; a fourth gear that is rotatable about the first axis and is engaged with the third gear; a fifth gear that is rotatable about the first axis, is disposed on a side of the fourth gear in the axial direction, and is connected to the fourth gear; and a sixth gear that is rotatable about the second axis and is engaged with the fifth gear, an outer diameter of the second gear being larger than an outer diameter of the first gear, an outer diameter of the fourth gear being larger than an outer diameter of the third gear, an outer diameter of the sixth gear being larger than an outer diameter of the fifth gear, an axial dimension of the second gear being smaller than an axial dimension of the fourth gear, and an axial dimension of the fourth gear being smaller than an axial dimension of the sixth gear.

[0011] The electric actuator according to the present application is characterized in that, in the electric actuator according to the above aspect,

[0012] an axial dimension of the first gear is smaller than an axial dimension of the third gear, and an axial dimension of the third gear is smaller than an axial dimension of the fifth gear.

[0013] The electric actuator according to the present application is characterized in that, in the electric actuator according to the above aspect,

[0014] the first gear is fixed to the first shaft,

[0015] the sixth gear is fixed to the second shaft.

[0016] The electric actuator according to the present application is characterized in that, in the electric actuator according to the above aspect,

[0017] the rotor is rotatable about the first axis,

[0018] the first shaft is fixed to the rotor.

[0019] The electric actuator according to the present application is characterized in that, in the electric actuator according to the above aspect,

[0020] provided with a housing that houses the first shaft, the second shaft, and the transmission mechanism inside,

[0021] a portion of the other side in the axial direction of the second shaft is located outside the housing.

[0022] Effects of the Invention

[0023] According to one embodiment of the present application, in an electric actuator, a transmission mechanism can be prevented from becoming large. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a perspective view showing an electric actuator of one embodiment.

[0025] Figure 2 is a cross-sectional view showing an electric actuator of one embodiment.

[0026] Figure 3 is a partially enlarged cross-sectional view showing an electric actuator of one embodiment.

[0027] Figure 4 is a perspective view showing a transmission mechanism of one embodiment.

[0028] SYMBOL EXPLANATION

[0029] 10 … housing, 20 … motor portion, 21 … rotor, 23 … first shaft, 60 … transmission mechanism, 61 … first gear, 63 … second gear, 64 … third gear, 66 … fourth gear, 67 … fifth gear, 68 … sixth gear, 70 … second shaft, 90 … electric actuator, J1 … first axis, J2 … second axis. DETAILED DESCRIPTION

[0030] In each drawing, the Z-axis direction is a vertical direction in which the positive side (+Z side) is the upper side and the negative side (-Z side) is the lower side. In the present embodiment, the upper side corresponds to the other side in the axial direction, and the lower side corresponds to the one side in the axial direction. Note that the upper side and the lower side are merely names for explaining the relative positional relationship of each part, and the actual arrangement relationship and the like can be an arrangement relationship and the like other than those indicated by the names.

[0031] In each drawing, the first direction D1 is a direction orthogonal to the Z-axis direction. In the following description, the side to which the arrow of the first direction D1 points (+D1 side) is referred to as "one side in the first direction D1", and the side opposite to the side to which the arrow of the first direction D1 points (-D1 side) is referred to as "the other side in the first direction D1". In each drawing, the second direction D2 is a direction orthogonal to both the Z-axis direction and the first direction D1.

[0032] The direction in which the first axis J1 extends, as shown in each figure, is parallel to the Z-axis direction. In this embodiment, the first axis J1 is an imaginary axis. The first axis J1 is the central axis of the first axis 23. In the following description, the direction parallel to the first axis J1 will be simply referred to as the "axial direction". The radial direction centered on the first axis J1 will be simply referred to as the "radial direction". The circumferential direction centered on the first axis J1 will be simply referred to as the "circumferential direction". In each figure, the circumferential direction is indicated by the arrow θ1.

[0033] Figure 1 The electric actuator 90 of this embodiment shown is installed in a vehicle. More specifically, the electric actuator 90 is, for example, mounted on an actuator device of a drive-by-wire parking system that is driven based on the driver's gear shifting operation. Figure 2 As shown, the electric actuator 90 includes a housing 10, a motor 20, a first shaft 23, a substrate holding part 40, a transmission mechanism 60, a second shaft 70, and a circuit board 80.

[0034] The housing 10 internally houses the motor unit 20, the first shaft 23, the substrate holding unit 40, the transmission mechanism 60, the second shaft 70, and the circuit board 80. The housing 10 has a housing body 11 and a cover component 17.

[0035] The housing body 11 is cylindrical, surrounding the first axis J1. The housing body 11 has an opening 11b on its upper side. Inside the housing body 11 are housed the motor unit 20, the lower portion of the first shaft 23, the substrate holding portion 40, the lower portion of the second shaft 70, and the circuit board 80. The housing body 11 has a main peripheral wall portion 13, a bottom wall portion 14, a connector housing 15, and a connector housing portion 16.

[0036] The main body peripheral wall portion 13 is generally cylindrical, extending axially around a first axis J1. The main body peripheral wall portion 13 surrounds the motor portion 20 radially outward. The main body peripheral wall portion 13 has a first stepped surface 13a and a second stepped surface 13b. The first stepped surface 13a and the second stepped surface 13b are both upward-facing stepped surfaces. The first stepped surface 13a and the second stepped surface 13b are both parts of the inner surface of the main body peripheral wall portion 13. Viewed axially, the first stepped surface 13a and the second stepped surface 13b are both generally annular, centered on the first axis J1. The first stepped surface 13a is located lower than the second stepped surface 13b. In this embodiment, the outer diameter of the first stepped surface 13a and the inner diameter of the second stepped surface 13b are the same size.

[0037] The bottom wall portion 14 is plate-shaped extending in a direction orthogonal to the axial direction. The bottom wall portion 14 is substantially circular plate-shaped centered on the first axis J1. An end portion of the bottom wall portion 14 on a radially outer side is connected to a lower end of the main body peripheral wall portion 13. A third support portion 14a is provided on the bottom wall portion 14. The third support portion 14a protrudes upward from the bottom wall portion 14. The third support portion 14a is cylindrical centered on the first axis J1. The third support portion 14a is open on an upper side. A third bearing 53 is installed on an inner side surface of the third support portion 14a.

[0038] The connector housing 15 is cylindrical extending in the axial direction. The connector housing 15 is open on an upper side. The connector housing 15 is disposed on one side (+D1 side) of the first direction D1 of the main body peripheral wall portion 13. The connector housing 15 is connected to the main body peripheral wall portion 13 in the first direction D1. As shown in FIG. 2, the connector housing 15 is substantially rectangular when viewed in the axial direction. As shown in FIG. 3, a second substrate holding portion 15a and a connector receiving portion 16 are provided on the connector housing 15. Figure 1 Figure 2

[0039] The second substrate holding portion 15a holds the circuit substrate 80. The second substrate holding portion 15a is substantially cylindrical protruding upward from the connector housing 15. Although the figure is omitted, two second substrate holding portions 15a are provided on the connector housing 15 in the present embodiment. The second substrate holding portions 15a are disposed apart in the second direction D2. Each second substrate holding portion 15a has a second shaft portion 15b, a second insertion portion 15c, and a second substrate support portion 15d. The second shaft portion 15b is substantially cylindrical protruding upward from the connector housing 15. The second insertion portion 15c is substantially cylindrical protruding upward from the second shaft portion 15b. An outer diameter of the second insertion portion 15c is smaller than an outer diameter of the second shaft portion 15b. The second substrate support portion 15d protrudes upward from the second insertion portion 15c. An outer diameter of the second substrate support portion 15d is larger than the outer diameter of the second insertion portion 15c.

[0040] The connector receiving portion 16 is substantially rectangular cylindrical protruding downward from the connector housing 15. The connector receiving portion 16 is open on a lower side. The connector receiving portion 16 holds a plurality of connector pins 57. Each connector pin 57 extends in the axial direction. A lower end of each connector pin 57 is located inside the connector receiving portion 16. An upper end of each connector pin 57 is connected to the circuit substrate 80.

[0041] The cover member 17 is cylindrical surrounding the first axis J1. The cover member 17 is open on a lower side. A portion of the upper side of the first shaft 23, the transmission mechanism 60, and a portion of the second shaft 70 are received inside the cover member 17. The cover member 17 is fixed to an upper end of the housing main body 11. The cover member 17 closes the opening portion 11b of the housing main body 11 from the upper side. As shown in FIG. 2, the cover member 17 is substantially rectangular when viewed in the axial direction. Figure 1 ​​As shown, a portion of the other side (-D1 side) of the first direction D1 of the cover member 17 has a substantially semicircular shape centered on the first axis J1 when viewed in the axial direction. A portion of the one side (+D1 side) of the first direction D1 of the cover member 17 has a substantially rectangular shape that surrounds the second axis J2 when viewed in the axial direction. As shown, the cover member 17 has a cover peripheral wall portion 18 and a top wall portion 19. Figure 2 As shown, the cover member 17 has a cover peripheral wall portion 18 and a top wall portion 19.

[0042] In the present embodiment, the second axis J2 is an imaginary axis that extends in the same direction as the axial direction of the first axis J1. The second axis J2 is located at a position on the one side (+D1 side) of the first direction D1 from the first axis J1. In the following description, a radial direction centered on the second axis J2 will be simply referred to as the "second radial direction", and a circumferential direction centered on the second axis J2 will be simply referred to as the "second circumferential direction". The second circumferential direction is indicated by an arrow θ2 in each figure.

[0043] The cover peripheral wall portion 18 has a cylindrical shape that extends in the axial direction. The cover peripheral wall portion 18 surrounds the transmission mechanism 60 from the radially outer side. The lower ends of the cover peripheral wall portion 18 are fixed to the upper ends of the body peripheral wall portion 13 and the upper end of the connector housing 15, respectively. Thus, the cover member 17 is fixed to the upper end of the housing body 11.

[0044] The top wall portion 19 is a plate shape that expands in a direction orthogonal to the axial direction. The radially outer end of the top wall portion 19 is connected to the upper end of the cover peripheral wall portion 18. The top wall portion 19 is provided with a first support portion 19a and a top wall hole portion 19c. The first support portion 19a protrudes upward from the top wall portion 19. The first support portion 19a has a cylindrical shape centered on the first axis J1. The first support portion 19a is open at the lower side. The first bearing 51 is installed on the inner side surface of the first support portion 19a.

[0045] The top wall hole portion 19c is a hole that penetrates the top wall portion 19 in the axial direction. The top wall hole portion 19c has a substantially circular shape centered on the second axis J2 when viewed in the axial direction. The second shaft 70 passes through the top wall hole portion 19c in the axial direction. Thus, the upper side portion of the second shaft 70, that is, the portion on the other side in the axial direction is located outside the housing 10.

[0046] The motor portion 20 is housed inside the housing body 11. The motor portion 20 has a rotor 21 and a stator 30. In the present embodiment, the rotor 21 is rotatable about the first axis J1. The rotor 21 can also be rotatable about an imaginary axis that is different from the first axis J1 and the second axis J2 and extends in the axial direction. In the present embodiment, the rotor 21 has a circular ring shape centered on the first axis J1. A magnet, not shown, is fixed to the rotor 21. The magnet is provided with a plurality of magnets arranged at intervals in the circumferential direction.

[0047] The first shaft 23 is rotatable about the first axis line J1. The first shaft 23 is substantially cylindrical in shape extending in the axial direction about the first axis line J1. The first shaft 23 extends in the axial direction across the inside of the housing main body 11 and the inside of the cover member 17. In the present embodiment, the first shaft 23 passes through the inside of the rotor 21 in the axial direction. The outer peripheral surface of the first shaft 23 is fixed to the rotor 21. That is, the first shaft 23 is fixed to the rotor 21. Thus, the rotation of the rotor 21 about the first axis line J1 is transmitted to the first shaft 23. The lower end of the first shaft 23 is supported by the third bearing 53 so as to be rotatable about the first axis line J1. The central portion of the first shaft 23 in the axial direction is supported by the second bearing 52 so as to be rotatable about the first axis line J1. The upper end of the first shaft 23 is located inside the first support portion 19a and is supported by the first bearing 51 so as to be rotatable about the first axis line J1. In addition, in the case where the rotor 21 is rotatable about an imaginary axis line different from the first axis line J1 and the second axis line J2, the rotation of the rotor 21 is transmitted to the first shaft 23, for example, via a gear or the like driving transmission member.

[0048] The stator 30 is arranged radially outward of the rotor 21. The stator 30 opposes the rotor 21 across a gap in the radial direction. The stator 30 has a stator core 31, an insulator 32, and a coil portion 35.

[0049] The stator core 31 is annular in shape surrounding the rotor 21 from the radially outer side. The stator core 31 opposes the rotor 21 across a gap in the radial direction. The stator core 31 has a core back portion 31a and a plurality of tooth portions 31b. The core back portion 31a is annular in shape about the first axis line J1. The surface of the core back portion 31a facing the lower side is supported in the axial direction by the first step surface 13a. Thus, the axial position of the stator core 31 with respect to the housing main body 11 is determined. The core back portion 31a is fixed to the inner side surface of the main body peripheral wall portion 13 facing the radially inner side. Thus, the stator 30 is fixed to the housing main body 11. Each tooth portion 31b protrudes from the core back portion 31a toward the radially inner side. Although not shown in the drawing, each tooth portion 31b is arranged at intervals along the circumferential direction. The insulator 32 is mounted to the stator core 31. The insulator 32 insulates the stator core 31 from the coil portion 35.

[0050] The coil portion 35 has a plurality of coil main body portions 35a and coil lead wires 35b. Each coil main body portion 35a is mounted to a different tooth portion 31b from one another across the insulator 32. The coil lead wire 35b is led upward from the coil main body portion 35a. The upper end of the coil lead wire 35b is connected to the circuit board 80. Thus, the coil portion 35 is electrically connected to the circuit board 80.

[0051] The substrate holding portion 40 holds the circuit substrate 80. The substrate holding portion 40 is housed inside the case main body 11. The substrate holding portion 40 is disposed at a position that is on the upper side than the motor portion 20 and on the lower side than the circuit substrate 80. The substrate holding portion 40 has a cylindrical portion 40a, a first substrate holding portion 40e, and a second support portion 40j.

[0052] The cylindrical portion 40a is in a cylindrical shape that protrudes in the axial direction with the first axis J1 as the center. The cylindrical portion 40a is open at the lower side. The lower end of the cylindrical portion 40a is supported in the axial direction by the second stepped surface 13b. Thereby, the position of the substrate holding portion 40 in the axial direction with respect to the case main body 11 is determined. The first through-hole 40b, the second through-hole 40c, and the third through-hole 40d are provided on the cylindrical portion 40a. The first through-hole 40b, the second through-hole 40c, and the third through-hole 40d are holes that pass through the cylindrical portion 40a in the axial direction, respectively.

[0053] The first through-hole 40b is in a substantially circular shape with the first axis J1 as the center. The first shaft 23 passes through the first through-hole 40b in the axial direction. The second through-hole 40c is in a substantially circular shape as viewed in the axial direction. Although the drawing symbol is omitted, in the present embodiment, three second through-holes 40c are provided on the cylindrical portion 40a. The second through-holes 40c are provided at substantially equal intervals along the circumferential direction. The coil lead wire 35b passes through each of the second through-holes 40c in the axial direction. The third through-hole 40d is in a substantially circular shape with the second axis J2 as the center. The fourth bearing 54 is installed on the inner peripheral surface of the third through-hole 40d.

[0054] The first substrate holding portion 40e holds the circuit substrate 80. The first substrate holding portion 40e is in a substantially cylindrical shape that protrudes upward from the cylindrical portion 40a. Although the drawing symbol is omitted, in the present embodiment, the substrate holding portion 40 has three first substrate holding portions 40e. The first substrate holding portions 40e are disposed at intervals along the circumferential direction. Each of the first substrate holding portions 40e has a first shaft portion 40f, a first insertion portion 40g, and a first substrate support portion 40h. The first shaft portion 40f is in a substantially cylindrical shape that protrudes upward from the cylindrical portion 40a. The first insertion portion 40g is in a substantially cylindrical shape that protrudes upward from the first shaft portion 40f. The outer diameter of the first insertion portion 40g is smaller than the outer diameter of the first shaft portion 40f. The first substrate support portion 40h protrudes upward from the first insertion portion 40g. The outer diameter of the first substrate support portion 40h is larger than the outer diameter of the first insertion portion 40g.

[0055] The second support portion 40j protrudes downward from the cylindrical portion 40a. The second support portion 40j is in a cylindrical shape with the first axis J1 as the center. The second support portion 40j is open at the lower side. The second bearing 52 is installed on the inner side surface of the second support portion 40j.

[0056] The circuit board 80 is a plate shape that extends in a direction orthogonal to the axial direction. The circuit board 80 is disposed inside the housing main body 11. The circuit board 80 is disposed at a position that is on an upper side than the board holding portion 40 and on a lower side than the transmission mechanism 60. As described above, the plurality of connector pins 57 are connected to the circuit board 80. When the plurality of connector pins 57 are electrically connected to an external power source (not illustrated), the circuit board 80 is supplied with power from the external power source. In addition, as described above, the plurality of coil lead wires 35b are connected to the circuit board 80. Thereby, power of the external power source is supplied to the coil portion 35 via the circuit board 80. The circuit board 80 is provided with a first board hole 80a, a second board hole 80b, a third board hole 80c, and a fourth board hole 80d. Each of the first board hole 80a, the second board hole 80b, the third board hole 80c, and the fourth board hole 80d is a hole that passes through the circuit board 80 in the axial direction.

[0057] The first board hole 80a is substantially circular when viewed from the axial direction. Although not illustrated, three first board holes 80a are provided on the circuit board 80. Each of the first board holes 80a overlaps with a different first board holding portion 40e when viewed from the axial direction. The first insertion portion 40g passes through each of the first board holes 80a in the axial direction. A face of the circuit board 80 toward the upper side is in contact with the first board support portion 40h in the axial direction. A face of the circuit board 80 toward the lower side is supported by the first shaft portion 40f in the axial direction. Thereby, the circuit board 80 is held by the board holding portion 40.

[0058] The second board hole 80b is substantially circular when viewed from the axial direction. Although not illustrated, two second board holes 80b are provided on the circuit board 80. Each of the second board holes 80b overlaps with a different second board holding portion 15a when viewed from the axial direction. The second insertion portion 15c passes through each of the second board holes 80b in the axial direction. A face of the circuit board 80 toward the upper side is in contact with the second board support portion 15d in the axial direction. A face of the circuit board 80 toward the lower side is supported by the second shaft portion 15b in the axial direction. Thereby, the circuit board 80 is held by the housing 10.

[0059] The third board hole 80c is substantially circular with the first axis J1 as a center. The first shaft 23 passes through the third board hole 80c in the axial direction. The fourth board hole 80d is substantially circular with the second axis J2 as a center. The second shaft 70 passes through the fourth board hole 80d in the axial direction.

[0060] The second shaft 70 outputs a driving force of the electric actuator 90. The second shaft 70 is a substantially cylindrical shape extending in the axial direction with the second axis line J2 as the center. The second shaft 70 is rotatable with the second axis line J2 as the center. The second shaft 70 is arranged radially apart from the first shaft 23. In the present embodiment, the second shaft 70 is arranged at a position on the first direction D1 side (+D1 side) than the first shaft 23. The second shaft 70 passes through the fourth substrate hole 80d and the top wall hole portion 19c, respectively, in the axial direction. The lower end of the second shaft 70 is positioned inside the third through-hole 40d. The lower end of the second shaft 70 is supported by the fourth bearing 54 so as to be rotatable with the second axis line J2 as the center. The portion of the second shaft 70 on the upper side protrudes to the outside of the housing 10 via the top wall hole portion 19c. The portion of the second shaft 70 protruding to the outside of the housing 10 is linked to a driven member not shown. Thus, the electric actuator 90 can drive the driven member.

[0061] The first bearing 51 is a circular ring shape with the first axis line J1 as the center. The first bearing 51 is mounted to the inner side surface of the first support portion 19a. The first bearing 51 supports the upper end of the first shaft 23 so as to be rotatable about the first axis line J1. In the present embodiment, the first bearing 51 is a sliding bearing. The first bearing 51 can be a ball bearing.

[0062] The second bearing 52 is a circular ring shape with the first axis line J1 as the center. The second bearing 52 is mounted to the inner side surface of the second support portion 40j. The second bearing 52 supports the central portion of the first shaft 23 in the axial direction so as to be rotatable about the first axis line J1. In the present embodiment, the second bearing 52 is a ball bearing. The second bearing 52 can be a sliding bearing.

[0063] The third bearing 53 is a circular ring shape with the first axis line J1 as the center. The third bearing 53 is mounted to the inner side surface of the third support portion 14a. The third bearing 53 supports the lower end of the first shaft 23 so as to be rotatable about the first axis line J1. In the present embodiment, the third bearing 53 is a ball bearing. The third bearing 53 can be a sliding bearing.

[0064] The fourth bearing 54 is a circular ring shape with the second axis line J2 as the center. The fourth bearing 54 is mounted to the inner side surface of the third through-hole 40d. The fourth bearing 54 supports the lower end of the second shaft 70 so as to be rotatable about the second axis line J2. In the present embodiment, the fourth bearing 54 is a sliding bearing. The fourth bearing 54 can be a ball bearing.

[0065] The transfer mechanism 60 is positioned above the circuit board 80. The transfer mechanism 60 is housed inside the cover member 17. In this embodiment, the transfer mechanism 60 is connected to both the first shaft 23 and the second shaft 70. The transfer mechanism 60 transfers the rotation of the first shaft 23 about the first axis J1 to the second shaft 70. Consequently, the second shaft 70 rotates about the second axis J2. In this embodiment, the transfer mechanism 60 decelerates the rotation of the first shaft 23 and transfers it to the second shaft 70. The transfer mechanism 60 can either increase the rotation speed of the first shaft 23 and transfer it to the second shaft 70, or it can transfer a rotation at the same speed as the rotation of the first shaft 23 to the second shaft 70. Figure 3 As shown, the transmission mechanism 60 includes a first gear 61, a first-stage gear 62, a second-stage gear 65, and a sixth gear 68. The rotation of the first shaft 23 is sequentially transmitted to the first gear 61, the first-stage gear 62, the second-stage gear 65, the sixth gear 68, and the second shaft 70.

[0066] The first gear 61 transmits the rotation of the first shaft 23 to the first-stage gear 62. The first gear 61 is an annular plate centered on the first axis J1. The first shaft 23 passes axially through the interior of the first gear 61. In this embodiment, the first gear 61 is fixed to the first shaft 23. Therefore, the first gear 61 can rotate together with the first shaft 23 around the first axis J1. Figure 4 As shown, a first gear portion 61a is provided on the radially outward surface of the first gear 61.

[0067] Alternatively, the first gear 61 may not be fixed to the first shaft 23. In this case, the transmission mechanism 60 has a plurality of gears including a fixed gear fixed to the first shaft 23, and the rotation of the first shaft 23 is transmitted to the first gear 61 via the plurality of gears.

[0068] The first-stage gear 62 transmits the rotation of the first gear 61 to the second-stage gear 65. For example... Figure 3 As shown, the first-stage gear 62 is an annular plate centered on the second axis J2. The second shaft 70 passes axially through the interior of the first-stage gear 62. The first-stage gear 62 is supported by the second shaft 70 so that it can rotate about the second axis J2. The first-stage gear 62 includes a second gear 63 and a third gear 64. The second gear 63 and the third gear 64 are part of the same single component.

[0069] The second gear 63 is an annular plate centered on the second axis J2. The second gear 63 is capable of rotating around the second axis J2. The second gear 63 is radially opposed to the first gear 61. Figure 4As shown, a second gear portion 63a, which meshes with the first gear portion 61a, is provided on the surface of the second gear 63 facing the second radial outward. Therefore, the second gear 63 meshes with the first gear 61. The outer diameter of the second gear 63 is larger than the outer diameter of the first gear 61. The number of teeth in the second gear portion 63a is greater than the number of teeth in the first gear portion 61a. As a result, the rotation of the first shaft 23 and the first gear 61 is slowed down and transmitted to the first-stage gear 62. Figure 3 As shown, the axial dimension T2 of the second gear 63 is approximately the same as the axial dimension T1 of the first gear 61.

[0070] The third gear 64 is an annular plate centered on the second axis J2. The third gear 64 is positioned lower than the second gear 63, i.e., on the axial side. The third gear 64 is axially connected to the second gear 63. Therefore, the third gear 64 can rotate together with the second gear 63 around the second axis J2. Figure 4 As shown, a third gear portion 64a is provided on the surface of the third gear 64 facing the second radially outward side. Figure 3 As shown, the axial dimension T3 of the third gear 64 is greater than the axial dimension T1 of the first gear 61 and the axial dimension T2 of the second gear 63. Therefore, the axial dimension T1 of the first gear 61 is less than the axial dimension T3 of the third gear 64.

[0071] The second-stage gear 65 transmits the rotation of the first-stage gear 62 to the sixth gear 68. The second-stage gear 65 is an annular plate centered on the first axis J1. The first shaft 23 passes axially through the interior of the second-stage gear 65. The second-stage gear 65 is supported by the first shaft 23 to enable rotation about the first axis J1. The second-stage gear 65 has a fourth gear 66 and a fifth gear 67. The fourth gear 66 and the fifth gear 67 are part of the same single component.

[0072] The fourth gear 66 is in the shape of an annular plate centered on the first axis J1. The fourth gear 66 is capable of rotating around the first axis J1. The fourth gear 66 is radially opposed to the third gear 64. Figure 4 As shown, a fourth gear portion 66a, which meshes with the third gear portion 64a, is provided on the radially outward surface of the fourth gear 66. Therefore, the fourth gear 66 meshes with the third gear 64. The outer diameter of the fourth gear 66 is larger than the outer diameter of the third gear 64. The number of teeth in the fourth gear portion 66a is greater than the number of teeth in the third gear portion 64a. As a result, the rotation of the first-stage gear 62 is reduced in speed and transmitted to the second-stage gear 65. Figure 3As shown, the axial dimension T4 of the fourth gear 66 is approximately the same as the axial dimension T3 of the third gear 64. The axial dimension T4 of the fourth gear 66 is greater than the axial dimension T1 of the first gear 61 and the axial dimension T2 of the second gear 63. Therefore, the axial dimension T2 of the second gear 63 is less than the axial dimension T4 of the fourth gear 66.

[0073] The fifth gear 67 is an annular plate centered on the first axis J1. The fifth gear 67 is positioned lower than the fourth gear 66, i.e., on the axial side. The fifth gear 67 is axially connected to the fourth gear 66. Therefore, the fifth gear 67 can rotate together with the fourth gear 66 around the first axis J1. Figure 4 As shown, a fifth gear portion 67a is provided on the radially outward surface of the fifth gear 67. (As indicated...) Figure 3 As shown, the axial dimension T5 of the fifth gear 67 is larger than the axial dimension T3 of the third gear 64 and the axial dimension T4 of the fourth gear 66. Therefore, the axial dimension T3 of the third gear 64 is smaller than the axial dimension T5 of the fifth gear 67.

[0074] The sixth gear 68 transmits the rotation of the second-stage gear 65 to the second shaft 70. The sixth gear 68 is an annular plate centered on the second axis J2. The sixth gear 68 is radially opposed to the fifth gear 67. The second shaft 70 passes axially through the interior of the sixth gear 68. The sixth gear 68 is capable of rotating about the second axis J2. Figure 4 As shown, a sixth gear portion 68a is provided on the surface of the sixth gear 68 facing the second radial outward, meshing with the fifth gear portion 67a. Therefore, the sixth gear 68 meshes with the fifth gear 67a. The outer diameter of the sixth gear 68 is larger than the outer diameter of the fifth gear 67. The number of teeth in the sixth gear portion 68a is greater than the number of teeth in the fifth gear portion 67a. As a result, the rotation of the second-stage gear 65 is slowed down and transmitted to the sixth gear 68. In this embodiment, the sixth gear 68 is fixed to the second shaft 70. Therefore, the second shaft 70 can rotate together with the sixth gear 68 about the second axis J2. Figure 3 As shown, the axial dimension T6 of the sixth gear 68 is approximately the same as the axial dimension T5 of the fifth gear 67. The axial dimension T6 of the sixth gear 68 is greater than the axial dimension T3 of the third gear 64 and the axial dimension T4 of the fourth gear 66. Therefore, the axial dimension T4 of the fourth gear 66 is smaller than the axial dimension T6 of the sixth gear 68.

[0075] Alternatively, the sixth gear 68 may not be fixed to the second shaft 70. In this case, the transmission mechanism 60 has a plurality of gears, including a fixed gear fixed to the second shaft 70, through which the rotation of the sixth gear 68 is transmitted to the second shaft 70.

[0076] As described above, the rotation of the first gear 61 is decelerated and transmitted to the first-stage gear 62, the rotation of the first-stage gear 62 is decelerated and transmitted to the second-stage gear 65, and the rotation of the second-stage gear 65 is decelerated and transmitted to the sixth gear 68. Thus, the transmission mechanism 60 decelerates and transmits the rotation of the first shaft 23 to the second shaft 70. In addition, as described above, the rotation of the first gear 61 is decelerated and transmitted to the first-stage gear 62, and the rotation of the first-stage gear 62 is decelerated and transmitted to the second-stage gear 65. Thus, the rotational torque applied to the third gear 64 and the fourth gear 66, respectively, is larger than the rotational torque applied to the first gear 61 and the second gear 63, respectively. In addition, as described above, the rotation of the second-stage gear 65 is decelerated and transmitted to the sixth gear 68. Thus, the rotational torque applied to the fifth gear 67 and the sixth gear 68, respectively, is larger than the rotational torque applied to the third gear 64 and the fourth gear 66, respectively.

[0077] According to the present embodiment, the transmission mechanism 60 has: the first gear 61 rotatable about the first axis line J1; the second gear 63 rotatable about the second axis line J2 and engaged with the first gear 61; the third gear 64 rotatable about the second axis line J2, disposed on the lower side, i.e., the one side in the axial direction, of the second gear 63, and connected to the second gear 63; the fourth gear 66 rotatable about the first axis line J1 and engaged with the third gear 64; the fifth gear 67 rotatable about the first axis line J1, disposed on the lower side of the fourth gear 66, and connected to the fourth gear 66; and the sixth gear 68 rotatable about the second axis line J2 and engaged with the fifth gear 67. Thus, the first gear 61, the fourth gear 66, and the fifth gear 67 can be disposed so as to overlap each other in the axial direction, and the second gear 63, the third gear 64, and the sixth gear 68 can be disposed so as to overlap each other in the axial direction. Thus, compared to a case where three or more gears included in the transmission mechanism 60 are arranged in the radial direction, it is possible to suppress the transmission mechanism 60 from being large in the radial direction. Thus, it is possible to suppress the electric actuator 90 from being large in the radial direction.

[0078] According to the present embodiment, the dimension T2 of the second gear 63 in the axial direction is smaller than the dimension T4 of the fourth gear 66 in the axial direction, and the dimension T4 of the fourth gear 66 in the axial direction is smaller than the dimension T6 of the sixth gear 68 in the axial direction. Thus, compared to a case where the dimension T2 of the second gear 63 in the axial direction and the dimension T4 of the fourth gear 66 in the axial direction are each equal to or larger than the dimension T6 of the sixth gear 68 in the axial direction, it is possible to suppress the transmission mechanism 60 from being large in the axial direction. Thus, it is possible to suppress the electric actuator 90 from being large in the axial direction.

[0079] In addition, in the present embodiment, compared with a case where the dimension T2 in the axial direction of the second gear 63 and the dimension T4 in the axial direction of the fourth gear 66 are each equal to or greater than the dimension T6 in the axial direction of the sixth gear 68, it is easy to narrow the contact areas of the first gear 61 and the second gear 63 and the contact areas of the third gear 64 and the fourth gear 66, respectively. Thus, it is possible to reduce the frictional forces between the first gear 61 and the second gear 63 and between the third gear 64 and the fourth gear 66, respectively, and thus it is possible to improve the driving transmission efficiency between the gears that mesh with each other. Therefore, it is possible to improve the driving transmission efficiency of the transmission mechanism 60.

[0080] According to the present embodiment, the outer diameter of the second gear 63 is greater than the outer diameter of the first gear 61, the outer diameter of the fourth gear 66 is greater than the outer diameter of the third gear 64, and the outer diameter of the sixth gear 68 is greater than the outer diameter of the fifth gear 67. Thus, as described above, the rotational torque applied to the third gear 64 and the fourth gear 66 is greater than the rotational torque applied to the first gear 61 and the second gear 63, and the rotational torque applied to the fifth gear 67 and the sixth gear 68 is greater than the rotational torque applied to the third gear 64 and the fourth gear 66. In contrast, in the present embodiment, as described above, the dimension T4 in the axial direction of the fourth gear 66 is greater than the dimension T2 in the axial direction of the second gear 63, and the dimension T6 in the axial direction of the sixth gear 68 is greater than the dimension T4 in the axial direction of the fourth gear 66. Thus, compared with a case where the dimension T4 in the axial direction of the fourth gear 66 and the dimension T6 in the axial direction of the sixth gear 68 are each equal to or less than the dimension T2 in the axial direction of the second gear 63, it is easy to expand the contact areas of the third gear 64 and the fourth gear 66 and the contact areas of the fifth gear 67 and the sixth gear 68, respectively. Thus, it is possible to reduce the stress applied to the fourth gear 66 and the sixth gear 68, respectively. Therefore, it is possible to suppress the deterioration of the fourth gear 66 and the sixth gear 68 due to wear and the like, and thus it is possible to improve the durability of the transmission mechanism 60.

[0081] According to the present embodiment, the dimension T1 in the axial direction of the first gear 61 is less than the dimension T3 in the axial direction of the third gear 64, and the dimension T3 in the axial direction of the third gear 64 is less than the dimension T5 in the axial direction of the fifth gear 67. Thus, compared with a case where the dimension T1 in the axial direction of the first gear 61 and the dimension T3 in the axial direction of the third gear 64 are each equal to or greater than the dimension T5 in the axial direction of the fifth gear 67, it is possible to more appropriately suppress the transmission mechanism 60 from being large in the axial direction. Therefore, it is possible to more appropriately suppress the electric actuator 90 from being large in the axial direction.

[0082] Further, in the present embodiment, as compared with a case where the dimension T1 in the axial direction of the first gear 61 and the dimension T3 in the axial direction of the third gear 64 are each equal to or greater than the dimension T5 in the axial direction of the fifth gear 67, the contact areas of the first gear 61 and the second gear 63 and the contact areas of the third gear 64 and the fourth gear 66 can each be more appropriately narrowed. Thus, the frictional forces of the first gear 61 and the second gear 63 and the frictional forces of the third gear 64 and the fourth gear 66 can each be more appropriately reduced. Therefore, the drive transmission efficiency of the transmission mechanism 60 can be more appropriately improved.

[0083] Further, in the present embodiment, as described above, the rotational torque applied to the third gear 64 and the fourth gear 66 is greater than the rotational torque applied to the first gear 61 and the second gear 63, and the rotational torque applied to the fifth gear 67 and the sixth gear 68 is greater than the rotational torque applied to the third gear 64 and the fourth gear 66. In contrast, in the present embodiment, as described above, the dimension T3 in the axial direction of the third gear 64 is greater than the dimension T1 in the axial direction of the first gear 61, and the dimension T5 in the axial direction of the fifth gear 67 is greater than the dimension T3 in the axial direction of the third gear 64. Therefore, as compared with a case where the dimension T3 in the axial direction of the third gear 64 and the dimension T5 in the axial direction of the fifth gear 67 are each equal to or less than the dimension T1 in the axial direction of the first gear 61, the stress applied to each of the third gear 64 and the fifth gear 67 can be reduced. Thus, the third gear 64 and the fifth gear 67 can be inhibited from deteriorating due to wear or the like, so the durability of the transmission mechanism 60 can be more appropriately improved.

[0084] According to the present embodiment, the first gear 61 is fixed to the first shaft 23, and the sixth gear 68 is fixed to the second shaft 70. Therefore, since the transmission mechanism 60 can be constituted by six gears, as compared with a case where the transmission mechanism 60 further has another driving transmission member such as a gear, the transmission mechanism 60 can be inhibited from being large-sized. Thus, the electric motor actuator 90 can be inhibited from being large-sized. Further, as compared with a case where the transmission mechanism 60 further has another driving transmission member such as a gear, the number of components of the transmission mechanism 60 can be inhibited from increasing. Therefore, the manufacturing cost and the manufacturing man-hours of the transmission mechanism 60 can be inhibited from increasing.

[0085] Further, in the present embodiment, as compared with a case where the transmission mechanism 60 further has another driving transmission member such as a gear, the number of components constituting the transmission mechanism 60 can be reduced. Therefore, the drive transmission efficiency of the transmission mechanism 60 can be inhibited from being reduced.

[0086] According to the present embodiment, the rotor 21 is able to rotate with the first axis J1 as a center, and the first shaft 23 is fixed to the rotor 21. Therefore, since the rotation of the rotor 21 is directly transmitted to the first shaft 23, the increase in the number of components of the electric actuator 90 can be more appropriately suppressed compared to a case where the rotation of the rotor 21 is transmitted to the first shaft 23 via another gear or the like. Therefore, the increase in the manufacturing cost and the manufacturing man-hours of the electric actuator 90 can be more appropriately suppressed.

[0087] According to the present embodiment, the electric actuator 90 is provided with the housing 10 that houses the first shaft 23, the second shaft 70, and the transmission mechanism 60 inside, and the portion of the second shaft 70 on the upper side, i.e., the other side in the axial direction, is located outside the housing 10. Therefore, as described above, the portion of the second shaft 70 that protrudes outside the housing 10 can be directly linked to the unillustrated driven component. Thus, compared to a case where the second shaft 70 and the driven component are indirectly linked via another component, the increase in the number of components of the electric actuator 90 can be more appropriately suppressed. Therefore, the increase in the manufacturing cost and the manufacturing man-hours of the electric actuator 90 can be more appropriately suppressed.

[0088] The above describes the embodiments of the present application, but the structures in the embodiments and combinations thereof and the like are examples, and addition, omission, substitution, and other changes of the structures can be made within the scope of the gist of the present application. Note that the present application is not limited by the embodiments.

[0089] The third gear can be disposed on the upper side, i.e., the other side in the axial direction, than the second gear, and the fifth gear can be disposed on the upper side than the fourth gear. In this structure, the transmission mechanism can also be suppressed from being large in the radial and axial directions.

[0090] Note that at least one of the first bearing and the second bearing can not be provided. In a case where the first bearing is not provided, the upper end of the first shaft is directly supported by the first support portion, and in a case where the second bearing is not provided, the central portion in the axial direction of the first shaft is directly supported by the second support portion.

[0091] The structure of the transmission mechanism is not particularly limited as long as the rotation of the first shaft can be transmitted to the second shaft. For example, the first shaft and the first gear can be part of the same single component, and the second shaft and the sixth gear can be part of the same single component.

[0092] The use of the electric actuator of the present application is not particularly limited. The electric actuator can be mounted on an actuator device of a shift-by-wire system that is driven based on a shift operation by a driver. Note that the electric actuator can also be mounted on a device other than a vehicle. Note that the structures described in the present specification can be appropriately combined within a range where they do not contradict each other.

[0093] Note that the present technology can employ the following structure.

[0094] (1) An electric actuator characterized by comprising: a motor portion; a first shaft that transmits rotation of a rotor possessed by the motor portion and is rotatable about a first axis; a second shaft that is rotatable about a second axis and is disposed separately from the first shaft in a radial direction about the first axis, the second axis extending in the same direction as an axial direction of the first axis; and a transmission mechanism that transmits rotation of the first shaft to the second shaft, the transmission mechanism comprising: a first gear that is rotatable about the first axis; a second gear that is rotatable about the second axis and is engaged with the first gear; a third gear that is rotatable about the second axis, is disposed on a side of the second gear in the axial direction, and is connected to the second gear; a fourth gear that is rotatable about the first axis and is engaged with the third gear; a fifth gear that is rotatable about the first axis, is disposed on a side of the fourth gear in the axial direction, and is connected to the fourth gear; and a sixth gear that is rotatable about the second axis and is engaged with the fifth gear, an outer diameter of the second gear being larger than an outer diameter of the first gear, an outer diameter of the fourth gear being larger than an outer diameter of the third gear, an outer diameter of the sixth gear being larger than an outer diameter of the fifth gear, a dimension of the axial direction of the second gear being smaller than a dimension of the axial direction of the fourth gear, and a dimension of the axial direction of the fourth gear being smaller than a dimension of the axial direction of the sixth gear.

[0095] (2) The electric actuator according to (1), characterized in that a dimension of the axial direction of the first gear is smaller than a dimension of the axial direction of the third gear, and a dimension of the axial direction of the third gear is smaller than a dimension of the axial direction of the fifth gear.

[0096] (3) The electric actuator according to (1) or (2), characterized in that the first gear is fixed to the first shaft, and the sixth gear is fixed to the second shaft.

[0097] (4) The electric actuator according to any one of (1) to (3), characterized in that the rotor is rotatable about the first axis, and the first shaft is fixed to the rotor.

[0098] (5) The electric actuator according to any one of (1) to (4), characterized by comprising a housing that houses the first shaft, the second shaft, and the transmission mechanism inside, respectively, a portion of the second shaft on the other side of the axial direction being located outside the housing.

Claims

1. An electric actuator, characterized by Possessing: a motor section; a first shaft that transmits rotation of a rotor possessed by the motor section and is rotatable about a first axis; a second shaft that is rotatable about a second axis that extends in the same direction as the axial direction of the first axis and is disposed separately from the first shaft in the radial direction about the first axis; and a transmission mechanism that transmits rotation of the first shaft to the second shaft, the transmission mechanism possesses: a first gear that is rotatable about the first axis; a second gear that is rotatable about the second axis and is engaged with the first gear; a third gear that is rotatable about the second axis, is disposed on the side of the axial direction from the second gear, and is connected to the second gear; a fourth gear that is rotatable about the first axis and is engaged with the third gear; a fifth gear that is rotatable about the first axis, is disposed on the side of the axial direction from the fourth gear, and is connected to the fourth gear; and a sixth gear that is rotatable about the second axis and is engaged with the fifth gear, the outer diameter of the second gear is larger than the outer diameter of the first gear, the outer diameter of the fourth gear is larger than the outer diameter of the third gear, the outer diameter of the sixth gear is larger than the outer diameter of the fifth gear, the axial dimension of the second gear is smaller than the axial dimension of the fourth gear, and the axial dimension of the fourth gear is smaller than the axial dimension of the sixth gear.

2. The electric actuator according to claim 1, wherein the axial dimension of the first gear is smaller than the axial dimension of the third gear, and the axial dimension of the third gear is smaller than the axial dimension of the fifth gear.

3. The electric actuator according to claim 1 or 2, wherein the first gear is fixed to the first shaft, the sixth gear is fixed to the second shaft.

4. The electric actuator according to claim 1 or 2, wherein the rotor is rotatable about the first axis, the first shaft is fixed to the rotor.

5. The electric actuator according to claim 1 or 2, wherein a housing that houses the first shaft, the second shaft, and the transmission mechanism inside is possessed, a portion of the second shaft on the other side of the axial direction is located outside the housing. ​

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