Rotary Actuator

Abstract

A rotary actuator (10) is used in a vehicle shift-by-wire system (11). The actuator includes a motor, a reducer, an output shaft, a fixed member and a limiting pin (53). The reducer includes a ring gear and a sun gear and reduces the motor speed. The sun gear meshes with the ring gear from the inner side of the ring gear. The output shaft outputs the motor rotation at the speed reduced by the reducer. The fixed member is arranged around the reducer. The limiting pin is arranged in the fixed member. The limiting pin is configured to prevent the sun gear from moving while allowing the sun gear to revolve around the motor rotation axis and rotate around an eccentric axis eccentric to the rotation axis. The limiting pin is a member separated from the fixed member. The limiting pin strength is equal to or greater than the maximum torque reaction force received from the sun gear. The limiting pin has an engagement portion engaged with the sun gear. The hardness difference between the engagement portion and the sun gear is defined as a first hardness difference. The hardness difference between the fixed member and the sun gear is defined as a second hardness difference. The first hardness difference is set to be less than the second hardness difference.

Description

Technical Field

[0001] The invention relates to a rotary actuator. Background Art

[0002] Conventionally, a rotary actuator used as a drive unit of a shift-by-wire system of a vehicle is known. Patent document 1 (JP2016-223526A) discloses an actuator in which the movement of a sun gear is restricted by a limiting pin provided in a reducer between a rotating shaft of a motor and an output shaft. The limiting pin is integrally formed with a fixing member as a single component. Summary of the invention

[0003] However, since the restricting pin is integrally formed with the fixing member as a single component, there are concerns that the positional accuracy of the restricting pin may be reduced, the strength of the restricting pin may be insufficient, and the restricting pin may be worn.

[0004] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rotary actuator which prevents degradation of position accuracy of a regulating pin, insufficient strength of the regulating pin, and wear of an adjusting pin.

[0005] One aspect of the present invention is a rotary actuator in a wire-controlled shift system for a vehicle. The actuator includes a motor, a reducer, an output shaft, a fixed member, and a limiting pin. The reducer includes a ring gear and a sun gear and the reducer reduces the rotation speed of the motor. The sun gear meshes with the ring gear from the inner side of the ring gear. The output shaft outputs the rotation of the motor at a reduced speed through the reducer. The fixed member is arranged around the reducer. The limiting pin is arranged in the fixed member. The limiting pin is configured to prevent the sun gear from moving while allowing the sun gear to revolve around the rotation axis of the motor and rotate around an eccentric axis eccentric to the rotation axis. The limiting pin is a separate member separated from the fixed member. The strength of the limiting pin is equal to or greater than the maximum torque reaction force received from the sun gear. The limiting pin has an engagement portion engaged with the sun gear. The hardness difference between the engagement portion and the sun gear is defined as a first hardness difference. The hardness difference between the fixed member and the sun gear is defined as a second hardness difference. The first hardness difference is set to be less than the second hardness difference.

[0006] According to one aspect, since the limiting pin is a separate member from the fixing member in which the limiting pin is provided, the reduction in the position accuracy of the limiting pin can be suppressed. In addition, by providing the limiting pin in consideration of the strength and hardness difference of the limiting pin, the insufficient strength and wear of the limiting pin can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a schematic diagram showing a shift-by-wire system to which the rotary actuator according to the first embodiment is applied.

[0008] Figure 2 It is shown Figure 1 Diagram of the gear shifting mechanism.

[0009] Figure 3 is a cross-sectional view of the rotary actuator according to the first embodiment.

[0010] Figure 4 It is along Figure 3 A cross-sectional view of the reducer taken along line IV-IV.

[0011] Figure 5 is a cross-sectional view of a rotary actuator according to a second embodiment.

[0012] Figure 6 is a schematic diagram of a limiting pin according to a third embodiment.

[0013] Figure 7 yes Figure 6 Vertical cross-section of .

[0014] Figure 8 is a cross-sectional view of a rotary actuator according to a fourth embodiment.

[0015] Fig. 9 is a schematic diagram of a limiting pin according to a fourth embodiment.

[0016] Fig.10 yes Fig. 9 A plan cross-sectional view of a circumferential stop.

[0017] Fig.11 is a schematic diagram of a limiting pin according to a fifth embodiment.

[0018] Fig.12 yes Fig.11 A plan cross-sectional view of a circumferential stop.

[0019] Fig.13 is a schematic diagram of a limiting pin according to a sixth embodiment.

[0020] Fig.14 yes Fig.13 A plan cross-sectional view of a circumferential stop.

[0021] Fig.15 is a schematic diagram of a limiting pin according to a seventh embodiment.

[0022] Fig.16 yes Fig.15 Vertical cross-section of . DETAILED DESCRIPTION

[0023] Hereinafter, a plurality of embodiments of a rotary actuator (hereinafter referred to as "actuator") will be described with reference to the accompanying drawings. In the embodiments, substantially the same components are denoted by the same reference numerals, and description thereof is omitted.

[0024] (First embodiment)

[0025] The actuator is used as a drive unit of a shift-by-wire system of a vehicle.

[0026] (Shift-by-wire system)

[0027] Will refer to Figure 1 and Figure 2 Describe the construction of a shift-by-wire system. Figure 1 As shown, the shift-by-wire system 11 includes a shift operation device 13 for instructing a shift position of a transmission 12, an actuator 10 for driving a shift position switching mechanism 14 of the transmission 12, a drive circuit 15 for energizing the actuator 10, and a control circuit 17. The control circuit 17 controls the drive circuit 15 based on a control signal for the shift position to drive the actuator 10. The drive circuit 15 and the control circuit 17 constitute an electronic control unit 18 (hereinafter, referred to as ECU 18).

[0028] like Figure 2 As shown, the shift gear switching mechanism 14 includes: a gear switching valve 20, which controls the supply of hydraulic pressure to the hydraulic operating mechanism in the transmission 12; a brake spring 21 and a brake rod 22, which are configured to maintain the gear; and a parking rod 25, which prevents the output shaft from rotating when the shift gear is switched to the parking gear by assembling the parking rod 24 into the parking gear 23 of the output shaft of the transmission 12; and a manual shaft 26, which rotates together with the brake rod 22.

[0029] The shift position switching mechanism 14 rotates the manual shaft 26 together with the brake lever 22 connected to the parking column 25 and the valve body 27 of the range switching valve 20 to change the parking column 25 and the valve body 27 to a position corresponding to the target shift position. The shift-by-wire system 11 is connected to the actuator 10 to electrically switch the shift position.

[0030] (Actuator)

[0031] Next, the configuration of the actuator 10 will be described. Figure 3 As shown, the actuator 10 includes: a motor 30, which serves as a driving power source; a reducer 50, which reduces the rotation speed of the motor 30; an output shaft 40, which outputs the rotation at a reduced speed; and a housing 60, which accommodates the motor 30, the reducer 50 and the output shaft 40.

[0032] The housing 60 includes a cylindrical upper housing portion 61 and a cup-shaped lower housing portion 62. A spacer 65 is formed between one end 63 and the other end 64 of the upper housing 61. The drive circuit 15 and the control circuit 17 are mounted thereon (see Figure 1) is provided on the inner side of one end 63. The plate 66 is fixed to the spacer 65 by, for example, hot forging. The plate 66 is covered by a plate cover 67, thereby ensuring shielding (waterproofing) of the plate 66. The lower housing part 62 is attached to the other end 64. The lower housing part 62 includes a cylindrical protrusion 69 protruding away from the upper housing 61. The manual shaft 26 is inserted into the cylindrical protrusion 69.

[0033] The motor 30 includes: a stator 31, which is press-fitted and fixed into a plate shell 68 at the other end 64; a rotor 32, which is disposed inside the stator 31; and a rotating shaft 33, which rotates around a rotation axis AX1 together with the rotor 32. The rotating shaft 33 is rotatably supported by both a bearing 34 disposed in the plate shell 68 and a motor bearing 35 disposed in the lower housing portion 62. In addition, the rotating shaft 33 has an eccentric portion 36 that is eccentric to the rotation axis AX1 at a position on the side of the rotor 32 facing the lower housing portion 62. The motor 30 is capable of bidirectional rotation by controlling the current supplied to the three-phase winding 38 constituting the stator 31 by the control circuit 17 (see Figure 1 ), and can also stop at a desired rotation position. The plate cover 67 has a through hole and the plug 39 is attached to the through hole. When a malfunction occurs, the rotating shaft 33 can be rotated manually after the plug 39 is removed.

[0034] like Figure 3 and Figure 4 As shown, the speed reducer 50 includes a ring gear 51, a sun gear 52, and a driven gear 55. The ring gear 51 is a two-tooth gear and has internal teeth 56 and external teeth 57. The ring gear 51 is provided coaxially with the rotation axis AX1 and is rotatably supported by a gear bearing 58 provided in the lower housing portion 62.

[0035] The sun gear 52 is rotatably supported around the eccentric axis AX2 by the bearing 37 assembled into the eccentric portion 36. The sun gear 52 meshes with the ring gear 51 and fits tightly inside the ring gear 51. That is, the sun gear 52 meshes with the ring gear 51 from the inside of the ring gear 5. When the rotating shaft 33 rotates, the sun gear 52 performs a planetary motion, wherein the sun gear 52 revolves around the rotating axis AX1 and rotates around the eccentric axis AX2. The sun gear 52 defines eight through holes 59 that penetrate the sun gear 52 in the axial direction. The through holes 59 are arranged at equal intervals along the circumferential direction of the sun gear 52. The limiting pins 53 engaged with the corresponding through holes 59 restrict the movement of the sun gear 52 while allowing the sun gear 52 to perform a planetary motion. The rotation speed of the sun gear 52 is reduced relative to the rotation speed of the rotating shaft 33, and the rotation of the sun gear 52 is transmitted to the ring gear 51.

[0036] The driven gear 55 is coaxially arranged with the output axis AX3 parallel to AX1. The driven gear 55 meshes with the external teeth 57 to circumscribe the ring gear 51. That is, the driven gear 55 meshes with the external teeth 57 from the outside of the ring gear 51. The rotation transmitted to the ring gear 51 via the meshing between the sun gear 52 and the internal teeth 56 is transmitted from the external teeth 57 to the driven gear 55. When the ring gear 51 rotates around the rotation axis AX1, the driven gear 55 rotates around the rotation axis AX3.

[0037] The output shaft 40 has a cylindrical shape and is disposed coaxially with the rotation axis AX3. The spacer 65 has a support through hole 89 coaxial with the rotation axis AX3. The output shaft 40 is rotatably supported around the rotation axis AX3 by a first flange bushing 46 fitted in the support through hole 89 and a second flange bushing 47 fitted inside the cylindrical protrusion 69. The driven gear 55 is fitted to the outside of the output shaft 40 and connected to the output shaft 40 to transmit rotation. The manual shaft 26 is inserted into the output shaft 40 and is coupled to the output shaft 40 by, for example, spline fitting to transmit rotation.

[0038] The actuator 10 further includes a support member 54 and a limiting pin 53. The support member 54 includes a small cylinder 48, a large cylinder 49, and a bottom 80. The small cylinder 48 is radially fitted to the motor bearing 35 outward and supports the motor bearing 35. The large cylinder 49 is radially fitted to the gear bearing 58 outward and supports the gear bearing 58. The bottom 80 is located at a position away from the sun gear 52 in the small cylinder 48 and the large cylinder 49. The limiting pin 53 protrudes toward the sun gear 52 from the area of ​​the bottom 80 located between the small cylinder 48 and the large cylinder 49. The support member 54 is embedded in the lower housing part 62 by insert molding and is held by the lower housing part 62. In addition, the support member 54 defines a through hole 41 that penetrates the support member 54 in the axial direction of the rotating shaft 33. Each through hole 41 is located between the large cylinder 49 and the corresponding limiting pin 53 in the radial direction of the motor bearing 35. A plurality of through holes 41 are arranged at equal intervals in the circumferential direction of the motor bearing 35.

[0039] The limiting pin 53 is integrally formed with the support member 54 using the same material. Each limiting pin 53 is a separate member separated from the lower housing portion 62 and has a strength equal to or greater than the maximum torque reaction force received from the sun gear 52. Each limiting pin 53 is located between the motor bearing 35 and the gear bearing 58 in the radial direction of the rotating shaft 33. The limiting pin 53 is inserted into the through hole 59 and engages with the inner wall of the through hole 59. The limiting pin 53 is configured to prevent the sun gear 52 from moving while allowing the sun gear 52 to revolve around the rotation axis of the motor 30 and rotate around an eccentric axis eccentric to the rotation axis. The limiting pin 53 includes an engaging portion 42. The hardness difference between the engaging portion 42 and the sun gear 52 is defined as a first hardness difference. The hardness difference between the lower housing portion 62 and the sun gear 52 is defined as a second hardness difference. In the present embodiment, the first hardness difference is set to be smaller than the second hardness difference.

[0040] The lower housing portion 62 is provided around the speed reducer 50 and is a fixing member for fixing the restricting pin 53 .

[0041] As described above in the first embodiment, when the rotating shaft 33 rotates, the sun gear 52 performs a planetary motion, in which the sun gear 52 revolves around the rotation axis AX1 and rotates around the eccentric axis AX2. The limiting pin 53 engages with the through hole 59 of the sun gear 52 to limit the movement of the sun gear 52 while allowing the sun gear 52 to perform a planetary motion. Each limiting pin 53 is a separate member separated from the lower housing portion 62 as a fixed member and has a strength equal to or greater than the maximum torque reaction force received from the sun gear 52. The first hardness difference between the engaging portion 42 of the limiting pin 53 and the sun gear 52 is set to be smaller than the second hardness difference between the lower housing portion 62 and the sun gear 52.

[0042] Since the limiting pin 53 is a separate member from the lower housing portion 62, it is possible to avoid degradation of the positional accuracy relative to the rotation shaft 33. In contrast, if the limiting pin 53 is formed integrally with the resin housing as a single member, the positional accuracy of the limiting pin 53 will be reduced due to the shrinkage of the resin molding. In addition, when the limiting pin 53 is formed integrally with the metal housing as a single member, the positional accuracy of the limiting pin 53 will be affected by the machining accuracy when the limiting pin 53 is manufactured by machining the molded housing.

[0043] Since the strength of the limiting pin 53 is equal to or greater than the maximum torque reaction force received from the sun gear 52, the limiting pin 53 can be prevented from being broken. Since the first hardness difference between the engaging portion 42 of each of the limiting pins 53 and the sun gear 52 is set to be smaller than the second hardness difference between the lower housing portion 62 and the sun gear 52, the limiting pin 53 can be more effectively prevented from being worn compared to a case where the limiting pin 53 and the lower housing portion 62 are integrally formed as a single member.

[0044] The restricting pin 53 is held by molding in the lower housing portion 62. Therefore, the restricting pin 53 can be easily fixed.

[0045] The support member 54 supports the motor bearing 35 and the gear bearing 58. Furthermore, since the restricting pin 53 is integrally formed with the support member 54 as a single member, the restricting pin 53 can be prevented from being displaced from the corresponding bearing, and thus a reduction in the transmission efficiency of the gear can be suppressed.

[0046] Furthermore, the support member 54 defines a through hole 41 penetrating the support member 54 in the axial direction of the rotating shaft 33. A plurality of through holes 41 are formed at equal intervals in the circumferential direction of the motor bearing 35. Each through hole 41 serves as a stopper for engaging the support member 54 with the lower housing portion 62.

[0047] (Second embodiment)

[0048] The second embodiment is the same as the first embodiment except for the following configuration. Figure 5 As shown, in the present embodiment, the support member 54 described in the first embodiment is omitted, and each limiting pin 81 constitutes a single member and is held by the lower housing portion 62 by press fitting. Each limiting pin 81 is a separate member separate from the lower housing portion 62 and has a strength equal to or greater than the maximum torque reaction force received from the sun gear 52. The first hardness difference between the engaging portion 42 of each limiting pin 81 and the sun gear 52 is set to be smaller than the second hardness difference between the lower housing portion 62 and the sun gear 52. As described above, even if the limiting pin 81 is held by the lower housing portion 62 by press fitting into the lower housing portion 62, if the limiting pin 81 has the same construction as that of the first embodiment, the same advantages as those of the first embodiment can be obtained.

[0049] (Third Embodiment)

[0050] The third embodiment is the same as the first embodiment except for the following configuration. Figure 6 and Figure 7 As shown, the limiting pin 82 is arranged to protrude from the lower housing portion 62 toward the sun gear and includes a flange 70 located at the proximal portion of the limiting pin 82. The flange 70 includes a contact portion 71 that contacts the lower housing portion 62 along the axial direction of the limiting pin 82. The contact portion 71 is an annular surface and contacts the lower housing portion 62 across the entire circumference of the limiting pin 82. With this construction, when the limiting pin 82 receives the torque reaction force F from the sun gear 52, the limiting pin 82 can be restricted from falling off.

[0051] (Fourth embodiment)

[0052] The fourth embodiment is the same as the first embodiment except for the following configuration. Figure 8As shown, the limiting pin 83 is held by the motor housing 44 of the motor 30 around the reducer 50 by molding. Figure 8 , the motor 30 is shown in a simplified manner.

[0053] The motor housing 44 is disposed around the speed reducer 50 and is a fixed member for fixing the limiting pins 83. Each limiting pin 83 is a separate member from the motor housing 44 and has a strength equal to or greater than the maximum torque reaction force received from the sun gear 52. The first hardness difference between the engaging portion 42 of each limiting pin 83 and the sun gear 52 is set to be smaller than the second hardness difference between the motor housing 44 and the sun gear 52.

[0054] The restricting pin 83 having the above-described configuration has the following advantages.

[0055] Since each restricting pin 83 is a separate member from the motor case 44 as a fixing member, it is possible to suppress a decrease in positional accuracy.

[0056] Since each limiting pin 83 has a strength equal to or greater than the maximum torque reaction force received from the sun gear 52, it is possible to prevent the limiting pin 83 from breaking. Since the first hardness difference between the engaging portion 42 of the limiting pin 83 and the sun gear 52 is set to be smaller than the second hardness difference between the motor housing 44 and the sun gear 52, it is possible to more effectively prevent the limiting pin 83 from being worn than in a case where the limiting pin 83 is formed integrally with the lower housing portion 62 as a single member.

[0057] That is, if the lower case portion 62 in the first embodiment and the motor case 44 in the third embodiment are regarded as fixed members, the advantages of the third embodiment are similar to those of the first embodiment.

[0058] Each limiting pin 83 has one end in a rectangular parallelepiped shape and is molded together with the motor housing 44, such as Fig. 9 and Fig.10 As shown, the one end serves as a circumferential stopper 72 engaged with the motor housing 44 in the circumferential direction of the limiting pin 83. The circumferential stopper 72 includes a plurality of corner portions 73 arranged in the circumferential direction. The circumferential stopper 72 prevents the motor housing 44 from moving in the circumferential direction by the corner portions 73 engaged with the motor housing 44. Since the limiting pin 83 has the circumferential stopper 72, it is possible to prevent the limiting pin 83 from falling off.

[0059] (Fifth Embodiment)

[0060] The fifth embodiment is the same as the second embodiment except for the following configuration. Fig.11 and Fig.12As shown, the limiting pin 84 protrudes from the lower housing portion 62 toward the sun gear. One end of the limiting pin 84 is molded together with the lower housing portion 62 and knurling is applied to the radial outer surface of the lower housing portion 62, and the knurling is a process of forming fine irregularities. One end of the limiting pin 84 serves as a circumferential stopper 72 that engages with the lower housing 62 in the circumferential direction of the limiting pin 84. The plurality of protrusions 74 formed on the circumferential stopper 72 serve as a circumferential stopper. Fig.12 In the figure, the size of the irregular portion of the knurling relative to the limiting pin 84 is shown exaggeratedly only for the purpose of easy understanding. Since the limiting pin 84 has a circumferential stopper, the limiting pin 84 can be prevented from falling off.

[0061] (Sixth embodiment)

[0062] The sixth embodiment is the same as the second embodiment except for the following configuration. Fig.13 and Fig.14 As shown, the limiting pin 85 protrudes from the lower housing portion 62 toward the sun gear. One end of the limiting pin 85 is formed as a columnar member having a star-shaped polygonal cross section. One end of the limiting pin 85 is molded together with the lower housing portion 62. The one end serves as a circumferential stopper 72 that engages with the lower housing 62 in the circumferential direction of the limiting pin 85. A plurality of protrusions 75 formed on the circumferential stopper 72 serve as a circumferential stopper. Since the limiting pin 85 has the circumferential stopper, it is possible to prevent the limiting pin 85 from falling off.

[0063] (Seventh Embodiment)

[0064] The seventh embodiment is the same as the second embodiment except for the following configuration. Fig.15 and Fig.16 As shown, the limiting pin 86 protrudes from the lower housing portion 62 toward the sun gear. One end of the limiting pin 86 has an annular groove 77 extending in the circumferential direction of the limiting pin 86 and is molded on the lower housing portion 62. The end of the limiting pin 86 close to the sun gear serves as an axial stopper 76 engaged with the lower housing portion 86. One side surface 78 of the annular groove 77 engages with the lower housing portion 86 and thus serves as a stopper. Since the limiting pin 86 has the axial stopper 76, it is possible to prevent the limiting pin 86 from falling off.

[0065] (Other embodiments)

[0066] In another embodiment of the present invention, the support member or the limiting pin is not limited to press fitting and molding, and may be retained by tightening or riveting.

[0067] In another embodiment of the present invention, by performing surface treatment on the limiting pin, the first hardness difference between the engaging portion of the limiting pin and the sun gear can be set to be smaller than the second hardness difference between the fixing member and the sun gear. In short, in order to make the hardness of the engaging portion of the limiting pin relatively high, a relatively hard material can be used, or the hardness of a part of the limiting pin can be made relatively high by performing surface treatment, etc.

[0068] In another embodiment of the present invention, the flange of the limiting pin may have a portion that contacts the fixing member. That is, it is not necessary for the entire limiting pin to contact the limiting pin in the circumferential direction. In short, the flange may have any shape as long as it contacts the fixing member in the axial direction.

[0069] In yet another embodiment of the present invention, the circumferential stopper defining the pin may have an irregularity formed in a portion of the defining pin in the circumferential direction. In short, the circumferential stopper may have any shape as long as it contacts the fixing member in the axial direction.

[0070] In another embodiment of the present invention, the axial stopper defining the pin may have an irregularity formed in a portion of the defining pin in the circumferential direction. In short, the circumferential stopper may have any shape as long as it contacts the fixing member in the axial direction to interfere with the fixing member.

[0071] In yet another embodiment of the present invention, the number of through holes of the sun gear is not limited to eight, and may be any number as long as the movement of the sun gear is restricted while allowing the planetary movement.

[0072] In another embodiment of the present invention, the through hole may not be provided in the bottom of the support member. In the case where the through hole is provided in the support member, the through hole may be provided not only between the large cylinder and the limiting pin, but also at a radially inward position of the limiting pin.

[0073] The present invention is not limited to the above-described embodiments, and various modifications may be made within the scope of the present invention without departing from the spirit of the present invention.

Claims

1. A rotary actuator (10) for use in a shift-by-wire system (11) for a vehicle, the rotary actuator comprising: Motor (30); a speed reducer (50) comprising a ring gear (51) and a sun gear (52) and reducing the rotation speed of the motor, the sun gear meshing with the ring gear from the inner side of the ring gear; an output shaft (40) which outputs the rotation of the motor at a rotation speed reduced by the speed reducer; A fixing member (44, 62) disposed around the reducer; as well as a limiting pin (53, 81 to 86) disposed in the fixing member, the limiting pin being configured to prevent the sun gear from moving while allowing the sun gear to orbit around the rotation axis (AX1) of the motor and to rotate around an eccentric axis (AX2) eccentric to the rotation axis, wherein: The limiting pin is a separate member from the fixing member, The limiting pin has a strength equal to or greater than the maximum torque reaction force received from the sun gear, The limiting pin has an engaging portion engaged with the sun gear, A hardness difference between the engagement portion and the sun gear is defined as a first hardness difference, A hardness difference between the fixed member and the sun gear is defined as a second hardness difference, and The first hardness difference is set to be smaller than the second hardness difference, The rotary actuator further comprises: a motor bearing (35) rotatably supporting a rotating shaft of the motor; a gear bearing (58) rotatably supporting the ring gear; and a support member (54) which supports the motor bearing and the gear bearing and which is held by the lower housing portion by insert molding, wherein The limiting pin and the supporting member are integrally formed as a single member.

2. The rotary actuator according to claim 1, wherein: The limiting pin is retained in the fixing member by molding or press-fitting.

3. The rotary actuator according to claim 1 or 2, wherein: The limiting pin (82) protrudes from the fixing member toward the sun gear and includes a flange (70) at a proximal end portion of the limiting pin, and The flange is in contact with the fixing member in the axial direction of the defining pin.

4. The rotary actuator according to claim 1 or 2, wherein: The limiting pins (83 to 85) include circumferential stoppers (72) that engage with the fixing member in the circumferential direction of the limiting pins.

5. The rotary actuator according to claim 1 or 2, wherein: The limiting pin (86) includes an axial stop (76) that engages the fixed member at an end of the limiting pin proximate the sun gear.

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