Electric Actuator

Abstract

To provide an electric actuator that can be easily replaced even when it is desired to replace the electric actuator independently of an output target of rotational force.SOLUTION: An electric actuator 100 includes: an output shaft 1 for outputting rotational force to an output target; an electric motor 2 for rotationally driving the output shaft 1; a controller 3 for controlling the electric motor 2; a speed reduction mechanism 4 disposed between the output shaft 1 and the motor 2; an irreversible mechanism 5 that is disposed between the output shaft 1 and the electric motor 2 to prevent back drive torque from being transmitted from an output side to an input side; a position sensor 6 for detecting a rotation position of the output shaft 1; and a housing 7 in which the output shaft 1, the electric motor 2, the controller 3, the speed reduction mechanism 4, the irreversible mechanism 5 and the position sensor 6 are disposed, and which can be attached to and detached from an installation target independently of the output target.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] BACKGROUND ART Electric actuators equipped with electric motors have been disclosed in the past (see, for example, Patent Document 1).

[0003] The above-mentioned Patent Document 1 discloses an electric actuator for aircraft including a rod, an electric motor for extending and retracting the rod, and a controller for controlling the electric motor. This electric actuator for aircraft is configured so that a nut threaded onto the screw shaft moves forward by rotating a screw shaft attached via a planetary gear mechanism or the like as a reduction mechanism, thereby extending the rod engaged with the nut. This electric actuator for aircraft also has an attachment part for attaching to the aircraft body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-95467 Summary of the Invention [Problem to be solved by the invention]

[0005] Although not explicitly stated in Patent Document 1, it is believed that the aircraft electric actuator, which includes a screw shaft, a nut, a rod, an electric motor, and a controller, is removed from the airframe via an attachment part. However, in this case, the electric actuator must be removed from the airframe (the attachment target) together with the rod (the target to which rotational force is output), which poses a problem in that it is not easy to replace the electric actuator independently of the rod, which is the target to which rotational force is output.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide an electric actuator that can be easily replaced, even when it is desired to replace the electric actuator independently of the object to which rotational force is output. [Means for solving the problem]

[0007] In order to achieve the above object, an electric actuator in one aspect of the present invention includes: an output shaft that outputs a rotational force to an output object; an electric motor that rotationally drives the output shaft; a controller that controls the electric motor; a speed reduction mechanism that is arranged between the output shaft and the electric motor; a non-reversible mechanism that is arranged between the output shaft and the electric motor and prevents backdrive torque from being transmitted from the output side to the input side; a position sensor that detects the rotational position of the output shaft; and a housing that is detachable from an attachment object independently of the output object and in which the output shaft, the electric motor, the controller, the speed reduction mechanism, the non-reversible mechanism, and the position sensor are arranged. The output shaft and the electric motor are arranged so that their rotation axes are offset from each other, and the controller is arranged on the opposite side of the electric motor with respect to the rotation axis of the output shaft. The controller is arranged in a space inside the housing formed by arranging the output shaft and the electric motor so that their rotation axes are offset from each other, and further includes a control cable through which the controller transmits a signal to control the electric motor. . [Effects of the Invention]

[0008] In the electric actuator according to the above aspect, an output shaft, an electric motor, a controller, a reduction mechanism, a non-reversible mechanism, and a position sensor are disposed in a housing that is detachable from an object to which the output force is to be attached, independently of the object to which the output force is to be output. This allows the electric actuator to be replaced using the housing that integrally contains the output shaft, the electric motor, the controller, the reduction mechanism, the non-reversible mechanism, and the position sensor as a single replacement unit, independently of the object to which the rotational force is to be output. As a result, the electric actuator can be easily replaced even when it is desired to replace the electric actuator independently of the object to which the rotational force is to be output.

[0009] In some cases, the electric motor, controller, reduction mechanism, and position sensor are located in separate locations. In this case, the number of parts increases and the assembly man-hours increase. Furthermore, when relatively strict assembly accuracy is required, the assembly man-hours increase even more. Furthermore, the increase in assembly man-hours also means an increase in the number of maintenance man-hours required when unexpected maintenance is required. In response to this, as described above, a housing is provided in which the output shaft, electric motor, controller, reduction mechanism, irreversible mechanism, and position sensor are located, and which is detachable from the mounting target, independent of the output target. This reduces the number of parts in the entire drive system to which the electric actuator is applied, as well as the assembly man-hours and maintenance man-hours, compared to when the electric motor, controller, reduction mechanism, and position sensor are located in separate locations. Furthermore, because the number of parts in the entire drive system to which the electric actuator is applied can be reduced, the weight of the entire drive system to which the electric actuator is applied can be reduced. As a result, when the electric actuator is applied to an aircraft, the fuel efficiency of the aircraft can be improved.

[0010] Furthermore, as described above, since the electric actuator includes a non-reversible mechanism, this configuration is particularly effective when the electric actuator is applied to a drive system that is prone to generating backdrive torque, such as the drive system of an aircraft flap. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing an electric actuator according to a first embodiment. [Figure 2] FIG. 3 is a cross-sectional view showing a disconnected state of the manual drive mechanism of the electric actuator according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing a connection state of a manual drive mechanism of the electric actuator according to the first embodiment. [Figure 4] FIG. 10 is a cross-sectional view showing an electric actuator according to a second embodiment. [Figure 5] FIG. 10 is a cross-sectional view showing an electric actuator according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0013] [First embodiment] The configuration of an electric actuator 100 according to a first embodiment will be described with reference to FIGS.

[0014] (Electric actuator configuration) As shown in Fig. 1, the electric actuator 100 includes an output shaft 1 that outputs a rotational force to an output object, an electric motor 2 that rotationally drives the output shaft 1, and a controller 3 that controls the electric motor 2. The electric actuator 100 is configured to output a rotational force from the output shaft 1 to the output object by rotating the output shaft 1 using the electric motor 2 under the control of the controller 3. The electric actuator 100 can be applied, for example, to the drive system of an aircraft flap. In this case, the electric actuator 100 is configured to drive the aircraft flap.

[0015] The electric actuator 100 further includes a speed reduction mechanism 4, a non-reversible mechanism 5, and a position sensor 6. In this embodiment, the electric actuator 100 further includes a metal housing 7 in which the output shaft 1, electric motor 2, controller 3, speed reduction mechanism 4, non-reversible mechanism 5, and position sensor 6 are arranged, and which is attachable to and detachable from an attachment target independently of the output target. The housing 7 is provided with mounting portions 7a for detachably mounting the housing 7 to an attachment target such as the main wing of an aircraft.

[0016] The electric actuator 100 further includes an overload limiting mechanism 8, a manual drive mechanism 9, and a through shaft 10. The overload limiting mechanism 8, the manual drive mechanism 9, and the through shaft 10 are disposed in a housing 7. The housing 7 is configured to be attachable to and detachable from an attachment target independently of an output target, with the housing 7 integrally containing the output shaft 1, the electric motor 2, the controller 3, the reduction mechanism 4, the irreversible mechanism 5, the position sensor 6, the overload limiting mechanism 8, the manual drive mechanism 9, and the through shaft 10. Specifically, the housing 7 is configured to be attachable to and detachable from an attachment target, with the housing 7 including the configuration shown in FIG. 1 . In other words, the electric actuator 100 is configured to be replaceable, with the entire configuration shown in FIG. 1 integrated.

[0017] The output shaft 1 is connected to a rotational object and is configured to rotate about a rotation axis C1, thereby rotating the rotational object about the rotation axis C1.

[0018] The electric motor 2 includes a motor core 21 and an output shaft 22. The motor core 21 has a stator 21a and a rotor 21b arranged inside the stator 21a. The output shaft 22 is connected to the rotor 21b so as to rotate integrally with the rotor 21b. The output shaft 22 is configured to rotate about a rotation axis C2 parallel to the rotation axis C1. The rotation axis C2 is arranged to be offset from the rotation axis C1 in the Y direction, which is perpendicular to the X direction parallel to the rotation axes C1 and C2. In other words, the output shaft 1 and the electric motor 2 are arranged so that the rotation axes C1 and C2 are offset from each other in the Y direction.

[0019] Furthermore, in this embodiment, the electric motor 2 has a motor core 21 disposed within the housing 7 without a dedicated motor housing. Specifically, the motor core 21 is held by a motor holder 7b provided within the housing 7. The motor holder 7b holds the motor core 21 so that the rotor 21b of the motor core 21 is rotatable.

[0020] The controller 3 is configured to receive a command signal from a host controller of the machine and to control the rotation speed of the electric motor 2 based on the input command signal. For example, when stop position information from the host controller matches position information from the position sensor 6, the controller 3 controls the electric motor 2 to stop rotation of the electric motor 2. At this time, because position information from the position sensor 6 can be acquired sequentially, the electric motor 2 may be controlled to start decelerating several rotations before the stop position. In this case, overshooting beyond the stop position can be suppressed, thereby improving the accuracy of the stop position.

[0021] In this embodiment, the reduction mechanism 4 includes a plurality (four) of reduction mechanisms (41-44). The plurality of reduction mechanisms (41-44) are a first spur gear reduction mechanism 41, a second spur gear reduction mechanism 42, a planetary gear reduction mechanism 43, and a trochoid gear reduction mechanism 44. Here, the power transmission system between the output shaft 1 and the electric motor 2 will be described. Between the output shaft 1 and the electric motor 2, the power transmission system includes the first spur gear reduction mechanism 41, an overload limiting mechanism 8, the second spur gear reduction mechanism 42, the irreversible mechanism 5, the planetary gear reduction mechanism 43, and the trochoid gear reduction mechanism 44, which are arranged in this order from the electric motor 2 side toward the output shaft 1 side. That is, the electric motor 2 is connected to the output shaft 1 so as to transmit power via a first spur gear reduction mechanism 41, an overload limiting mechanism 8, a second spur gear reduction mechanism 42, a non-reversible mechanism 5, a planetary gear reduction mechanism 43, and a trochoid gear reduction mechanism 44.

[0022] The first spur gear reduction mechanism 41 includes a first spur gear portion 41a and a second spur gear portion 41b. The first spur gear portion 41a is disposed coaxially with the electric motor 2 and is connected to the output shaft portion 22 of the electric motor 2 so as to rotate integrally therewith. The second spur gear portion 41b has teeth that mesh with the first spur gear portion 41a. The second spur gear portion 41b is also connected to the overload limiting mechanism 8.

[0023] The overload limiting mechanism 8 is provided to avoid torque overload. For example, if a driving element on the flap side becomes stuck, the controller 3 suddenly stops the electric motor 2. In this case, a torque overload occurs due to stall torque generated in the electric motor 2 when the electric motor 2 is stopped and spike torque generated in the power transmission system between the output shaft 1 and the electric motor 2 due to the moment of inertia. The overload limiting mechanism 8 is provided to avoid such torque overload. In this embodiment, the overload limiting mechanism 8 is a slip clutch that avoids torque overload by causing slip when a specified torque is reached.

[0024] The overload limiting mechanism 8 includes a friction portion 81, a preload spring 82, and a shaft portion 83. The friction portion 81 has a friction surface that generates a friction force to connect the second spur gear portion 41b and the shaft portion 83 so as to transmit the rotation of the second spur gear portion 41b. The preload spring 82 is a compression coil spring that biases the friction portion 81 in the X direction to increase the friction force generated on the friction surface of the friction portion 81. The preload spring 82 is configured so that the load applied to the friction portion 81 can be adjusted. When a force greater than the friction force (i.e., a force greater than a specified torque) acts on the friction surface of the friction portion 81 while biased by the preload spring 82, slippage occurs on the friction surface of the friction portion 81. As a result, rotation is no longer transmitted between the second spur gear portion 41b and the shaft portion 83, thereby avoiding torque overload.

[0025] The second spur gear portion 41b, a friction portion 81, and a preload spring 82 are attached to the shaft portion 83. The shaft portion 83 is configured to rotate by the rotation of the second spur gear portion 41b being transmitted via the friction portion 81. A gear portion 83a connected to the second spur gear reduction mechanism 42 is provided on the output side of the shaft portion 83.

[0026] The second spur gear reduction mechanism 42 includes a spur gear portion 42a and an output portion 42b. The teeth of the spur gear portion 42a mesh with those of a gear portion 83a of the overload limiting mechanism 8. The output portion 42b rotates integrally with the spur gear portion 42a and is connected to the non-reversible mechanism 5.

[0027] The non-reversible mechanism 5 is configured to prevent backdrive torque from being transmitted from the output side (output shaft 1 side) to the input side (electric motor 2 side). The non-reversible mechanism 5 transmits drive torque from the input side (electric motor 2 side) to the output side (output shaft 1 side), but is also configured to prevent backdrive torque from being transmitted to the input side (electric motor 2 side) when backdrive torque acts on the output side (output shaft 1 side). Here, aerodynamic forces act on the flaps while the aircraft is in flight, and a backdrive torque acts from the flap side to the output shaft 1 due to the aerodynamic forces. In this case, the non-reversible mechanism 5 functions to prevent rotation of the output shaft 1 due to the backdrive torque, maintaining the flap angle, and also to prevent the transmission of backdrive torque to the electric motor 2 side.

[0028] The irreversible mechanism 5 includes a shaft portion 51, a ball ramp portion 52, and a brake portion 53. The output portion 42b of the second spur gear reduction mechanism 42 is connected to the input side of the shaft portion 51 so as to rotate integrally. The planetary gear reduction mechanism 43 is connected to the output side of the shaft portion 51. The ball ramp portion 52 is connected to a portion between the input and output sides of the shaft portion 51. The ball ramp portion 52 has a ball and a groove-shaped ball ramp that accommodates the ball, and functions as a conversion mechanism that converts backdrive torque into axial force. The brake portion 53 has a tapered surface that tapers toward the direction in which the axial force from the ball ramp portion 52 acts, and has opposing brake surfaces. When the axial force from the ball ramp portion 52 acts, one brake surface of the brake portion 53 is pressed against the other brake surface, generating a brake torque. This brake torque prevents the transmission of the backdrive torque.

[0029] Although the example in which the non-reversible mechanism 5 converts backdrive torque into an axial force to generate a brake torque has been described, the non-reversible mechanism 5 is not limited to this example. For example, the non-reversible mechanism 5 may be configured to convert backdrive torque into a radial force to generate a brake torque. That is, the non-reversible mechanism 5 may be configured to include a ball ramp unit that converts backdrive torque into a radial force, and a brake unit that generates a brake torque when the radial force from the ball ramp unit acts.

[0030] The planetary gear reduction mechanism 43 includes a sun gear portion 43a, multiple planet gear portions 43b, a ring gear portion 43c, and a planet carrier portion 43d. The sun gear portion 43a is provided as part of the shaft portion 51 at the output end of the shaft portion 51 of the non-reversible mechanism 5, and its teeth mesh with those of the multiple planet gear portions 43b. The multiple planet gear portions 43b are configured to rotate while revolving around the sun gear portion 43a. The multiple planet gear portions 43b are disposed between the sun gear portion 43a and the ring gear portion 43c, and their teeth mesh with those of both the sun gear portion 43a and the ring gear portion 43c. The ring gear portion 43c is disposed outside the multiple planet gear portions 43b and is fixed so as not to rotate. The planetary carrier portion 43d is connected to the plurality of planetary gear portions 43b and is configured to extract and output the rotation of the plurality of planetary gear portions 43b. The planetary carrier portion 43d is also connected to the trochoid gear reduction mechanism 44.

[0031] The trochoid gear reduction mechanism 44 includes an input shaft 44a, multiple crankshafts 44b, a trochoid gear 44c, multiple outer pins 44d, and multiple output shafts 44e. The input side of the input shaft 44a is connected to the output shaft of the planetary carrier 43d. The output side of the input shaft 44a is provided with spur gears whose teeth mesh with those of the multiple crankshafts 44b. The multiple crankshafts 44b are provided with eccentric portions for eccentric motion. The trochoid gear 44c is connected to the eccentric portion of the crankshaft 44b. The trochoid gear 44c is configured to mesh with the multiple outer pins 44d and perform eccentric motion with the crankshaft 44b. The multiple outer pins 44d are rotatably arranged in a groove-shaped pin arrangement portion outside the trochoid gear 44c. The output shaft portion 44e is configured to extract the rotation of the trochoid gear portion 44c via the crankshaft portion 44b, thereby rotating the output shaft 1 around the rotation axis C1.

[0032] The position sensor 6 is an encoder that detects the rotational position of the output shaft 1. In this embodiment, the position sensor 6 is connected to a through shaft 10, which is connected to the output shaft 1, via an anti-backlash gear portion 61a. One end of the through shaft 10 is connected to the output shaft 1 with a nut and is configured to rotate integrally with the output shaft 1 around the rotation axis C1. The other end of the through shaft 10 is provided with a spur gear portion 11, the teeth of which mesh with those of the anti-backlash gear portion 61a. The position sensor 6 is connected to the through shaft 10 via the anti-backlash gear portion 61a and the spur gear portion 11. The structure of the anti-backlash gear portion 61a is not particularly limited, but for example, a structure in which two spur gear portions stacked in the axial direction are biased by a spring to sandwich the teeth of the mating spur gear portion (spur gear portion 11) between the teeth of the two spur gear portions to eliminate backlash can be employed. In addition, the anti-backlash gear portion 61a is provided on the shaft portion 61 of the position sensor 6. The position sensor 6 is configured to detect the rotational position of the output shaft 1 based on the rotation of the output shaft 1 transmitted via the through shaft 10, the spur gear portion 11, and the anti-backlash gear portion 61a.

[0033] Furthermore, a plurality (two) of position sensors 6 are provided, aligned in the circumferential direction around the rotation axis C1. This allows the rotational position of the output shaft 1 to be detected by the plurality (two) position sensors 6, so that even if one position sensor 6 fails, position detection can continue by the other position sensor 6, ensuring redundancy in position detection. All of the plurality of position sensors 6 are connected to the through shaft 10 via the spur gear portion 11.

[0034] In this embodiment, the multiple position sensors 6 are disposed on the opposite side of the electric motor 2 with respect to the rotation axis C1 of the output shaft 1. The multiple position sensors 6 are disposed spaced apart from the electric motor 2 in the Y direction because the output shaft 1 and the electric motor 2 are connected via the first spur gear reduction mechanism 41 and the second spur gear reduction mechanism 42 so as to be spaced apart from each other in the Y direction.

[0035] The housing 7 includes a controller-side housing 71 and a drive-unit-side housing 72. The controller 3 is accommodated and disposed in the controller-side housing 71. The controller-side housing 71 is configured to be detachable from the drive-unit-side housing 72. The drive-unit-side housing 72 accommodates and disposes an output shaft 1, an electric motor 2, a reduction mechanism 4 (first spur gear reduction mechanism 41, second spur gear reduction mechanism 42, planetary gear reduction mechanism 43, and trochoid gear reduction mechanism 44), a non-reversible mechanism 5, a position sensor 6, an overload limiting mechanism 8, a manual drive mechanism 9, and a through shaft 10. The connection portion of the output shaft 1 with the rotation target and the manual operation portion of the manual drive mechanism 9 are disposed outside the drive-unit-side housing 72.

[0036] Furthermore, in the drive unit-side housing 72, the output shaft 1 and the electric motor 2 are not coaxially arranged but are spaced apart in the Y direction, forming a space 72a. The space 72a is formed at a position that generally overlaps the output shaft 1 in the X direction and the motor core 21 of the electric motor 2 in the Y direction. A control cable 12, which transmits signals from the controller 3 to control the electric motor 2, is also arranged in the space 72a. This allows the control cable 12 to be easily connected to the electric motor 2 by effectively utilizing the space 72a. Furthermore, since the control cable 12 can be arranged inside the housing 7, external electromagnetic interference with the control cable 12 can be minimized, thereby improving the control accuracy of the electric motor 2. A cable guide 13 for passing cables such as the control cable 12 is also arranged in the space 72a. The cable guide 13 is provided to communicate between the controller-side housing 71 and the drive unit-side housing 72. The control cable 12 is arranged through a cable guide portion 13 from inside the controller side housing portion 71 to inside the drive unit side housing portion 72, and connects the controller 3 and the electric motor 2.

[0037] The manual drive mechanism 9 is provided for manually rotating the output shaft 1 with a manual tool. Specifically, the manual drive mechanism 9 is connected to the first spur gear reduction mechanism 41. The manual drive mechanism 9 is configured to rotate the first spur gear reduction mechanism 41 when rotated by the manual tool. As a result, the manual drive mechanism 9 is configured to rotate the output shaft 1 via the power transmission system other than the first spur gear reduction mechanism 41 (the overload limiting mechanism 8, the second spur gear reduction mechanism 42, the irreversible mechanism 5, the planetary gear reduction mechanism 43, and the trochoid gear reduction mechanism 44). The manual drive mechanism 9, together with the first spur gear portion 41a of the first spur gear reduction mechanism 41, is arranged coaxially with the electric motor 2.

[0038] 2 and 3, in this embodiment, the manual drive mechanism 9 is configured to be switchable between a connected state (see FIG. 3) in which it is connected to the first spur gear reduction mechanism 41 and a disconnected state (see FIG. 2) in which it is not connected to the first spur gear reduction mechanism 41. Specifically, the manual drive mechanism 9 includes a moving unit 91 having a reduction mechanism engaging portion 91a at one end that engages with the first spur gear reduction mechanism 41 and a tool engaging portion 91b at the other end that engages with a manual tool, and a biasing portion 92 that biases the moving unit 91 to move in the X direction so as to switch between the connected state and the disconnected state. When the electric motor 2 is driven, the manual drive mechanism 9 is disconnected from the first spur gear reduction mechanism 41.

[0039] The reduction mechanism engaging portion 91a is made of a key and is configured to engage with an engaging portion 41aa made of a key groove provided in the shaft portion of the first spur gear portion 41 of the first spur gear reduction mechanism 41. The tool engaging portion 91b is made of a recess recessed toward the first spur gear portion 41a side and is configured to engage with a protrusion of a manual operating tool.

[0040] Furthermore, the moving unit 91 is held by a holding unit 93 fixed to the housing 7 so as to be movable in the X direction and rotatable around the X direction. The moving unit 91 is also provided with a restricting unit 91c for restricting movement of the moving unit 91 in the X direction at a position in the disconnected state. The restricting unit 91c protrudes in the Y direction from the main body of the moving unit 91 and faces a restricting surface 93a of the holding unit 93 in the X direction. The restricting unit 91c is configured to restrict movement of the moving unit 91 in the X direction at a position in the disconnected state by abutting against the restricting surface 93a of the holding unit 93 in the X direction.

[0041] The biasing portion 92 is formed of a spring such as a compression coil spring and applies a biasing force to the moving portion 91 so that the moving portion 91 is in a disconnected state. When the moving portion 91 is pushed in by a manual tool against the biasing force of the biasing portion 92, the moving portion 91 moves to a connected state position, and the reduction mechanism engaging portion 91a engages with the engaging portion 41aa of the first spur gear portion 41a. This enables torque transmission from the manual drive mechanism 9 to the first spur gear reduction mechanism 41. When the manual tool is removed and the biasing portion 92 biases the moving portion 91, the moving portion 91 moves to a disconnected state position, and the reduction mechanism engaging portion 91a disengages from the engaging portion 41aa of the first spur gear portion 41a. This disables torque transmission from the manual drive mechanism 9 to the first spur gear reduction mechanism 41.

[0042] (Driving operation of output shaft by electric motor) When the electric motor 2 is driven by a command from the controller 3, the rotational force of the electric motor 2 is transmitted to the output shaft 1 while being reduced in speed via the first spur gear reduction mechanism 41, the overload limiting mechanism 8, the second spur gear reduction mechanism 42, the irreversible mechanism 5, the planetary gear reduction mechanism 43, and the trochoid gear reduction mechanism 44. This causes the output shaft 1 to rotate, and the output shaft 1 outputs the rotational force to an output target connected to the output shaft 1. In addition, the through shaft 10 connected to the output shaft 1 rotates, and the rotational position of the output shaft 1 is detected by the position sensor 6 connected to the through shaft 10 via the spur gear portion 11 and the anti-backlash gear portion 61a. In addition, since the manual drive mechanism 9 is in a disconnected state when the electric motor 2 is driven, the manual drive mechanism 9 does not affect the rotation of the output shaft 1 driven by the electric motor 2.

[0043] (Driving operation of output shaft by manual drive mechanism) When the moving part 91 of the manual drive mechanism 9 is pushed in by the manual tool, the reduction mechanism engaging part 91a of the moving part 91 engages with the engaging part 41aa of the first spur gear part 41a. When the manual tool is rotated, the moving part 91 rotates, and the first spur gear part 41a engaged with the moving part 91 also rotates. As a result, the rotational force of the manual tool is transmitted to the output shaft 1 via the overload limiting mechanism 8, the second spur gear reduction mechanism 42, the irreversible mechanism 5, the planetary gear reduction mechanism 43, and the trochoid gear reduction mechanism 44, causing the output shaft 1 to rotate.

[0044] (Effects of the first embodiment) In the first embodiment, the following effects can be obtained.

[0045] In the first embodiment, as described above, the electric actuator 100 comprises an output shaft 1 that outputs a rotational force to an output target, an electric motor 2 that rotates the output shaft 1, a controller 3 that controls the electric motor 2, a reduction mechanism 4 arranged between the output shaft 1 and the electric motor 2, a non-reversible mechanism 5 that is arranged between the output shaft 1 and the electric motor 2 and prevents backdrive torque from being transmitted from the output side to the input side, a position sensor 6 that detects the rotational position of the output shaft 1, and a housing 7 in which the output shaft 1, the electric motor 2, the controller 3, the reduction mechanism 4, the non-reversible mechanism 5, and the position sensor 6 are arranged, and which is attachable to and detachable from an attachment target independently of the output target.

[0046] This allows the electric actuator 100 to be replaced independently of the object to which the rotational force is output, using the housing 7, which integrally contains the output shaft 1, electric motor 2, controller 3, speed reduction mechanism 4, irreversible mechanism 5, and position sensor 6, as a single replacement unit. As a result, the electric actuator 100 can be easily replaced even when it is desired to replace the electric actuator 100 independently of the object to which the rotational force is output.

[0047] In some cases, the electric motor 2, controller 3, reduction mechanism 4, and position sensor 6 are disposed in separate locations. In this case, the number of parts increases and the number of assembly steps increases. Furthermore, when relatively strict assembly accuracy is required, the number of assembly steps increases further. Furthermore, the increase in assembly steps also means an increase in the number of maintenance steps required when unexpected maintenance is required. In response to this, as described above, the output shaft 1, electric motor 2, controller 3, reduction mechanism 4, irreversible mechanism 5, and position sensor 6 are disposed in a housing 7 that is detachable from the output target. This reduces the number of parts in the entire drive system to which the electric actuator 100 is applied, as well as the number of assembly steps and maintenance steps, compared to when the electric motor 2, controller 3, reduction mechanism 4, and position sensor 6 are disposed in separate locations. Furthermore, since the number of parts in the entire drive system to which the electric actuator 100 is applied can be reduced, the weight of the entire drive system to which the electric actuator 100 is applied can be reduced. As a result, in this embodiment in which the electric actuator 100 is applied to an aircraft, the fuel efficiency of the aircraft can be improved.

[0048] Furthermore, as described above, the electric actuator 100 includes the irreversible mechanism 5, and therefore this configuration is particularly effective when the electric actuator 100 is applied to a drive system that is prone to generating backdrive torque, such as the drive system of an aircraft flap, as in this embodiment.

[0049] Furthermore, in the first embodiment, the following additional effects can be obtained by configuring as follows.

[0050] That is, in the first embodiment, as described above, the reduction mechanism 4 includes a plurality of reduction mechanisms 41 to 44. This improves the degree of freedom in designing the reduction ratio of the electric actuator 100, so that a desired reduction ratio can be easily obtained while easily replacing the electric actuator 100 independently of the target to which the rotational force is output. Furthermore, even when a high reduction ratio is required, a high reduction ratio can be easily achieved.

[0051] Furthermore, in the first embodiment, as described above, the reduction mechanism 4 includes the trochoid gear reduction mechanism 44, the planetary gear reduction mechanism 43, and the spur gear reduction mechanisms 41 and 42. As a result, since the reduction mechanism 4 includes the trochoid gear reduction mechanism 44, high torque transmission efficiency can be achieved, and the power (torque) required for the electric motor 2 can be reduced. As a result, the electric motor 2 can be made smaller and lighter, and the electric actuator 100 can be made smaller and lighter. Furthermore, since the reduction mechanism 4 includes the planetary gear reduction mechanism 43, a high reduction ratio can be achieved, and this makes it easier to select or design the electric motor 2 with respect to the rotation speed and torque. Furthermore, since the reduction mechanism 4 includes the spur gear reduction mechanisms 41 and 42, the reduction mechanism 4 can be configured with a simple structure.

[0052] Furthermore, in the first embodiment, as described above, the output shaft 1 and the electric motor 2 are arranged so that their rotational axes C1, C2 are misaligned, and the position sensor 6 is arranged on the opposite side of the rotational axis C1 of the output shaft 1 from the electric motor 2. This allows the position sensor 6 and the electric motor 2 to be arranged at a distance from each other, making it easier to arrange the position sensor 6 than when the output shaft 1 and the electric motor 2 are arranged coaxially, making it difficult to arrange the position sensor 6.

[0053] Furthermore, in the first embodiment, as described above, the electric actuator 100 includes the through shaft 10 connected to the output shaft 1. The position sensor 6 is connected to the through shaft 10 via the anti-backlash gear portion 61a. This allows the position sensor 6 to detect the rotational position of the output shaft 1 in a backlash-free state, thereby preventing deviation in the detection position due to backlash. As a result, the detection accuracy of the rotational position of the output shaft 1 by the position sensor 6 can be improved.

[0054] Furthermore, in the first embodiment, as described above, the electric actuator 100 includes the manual drive mechanism 9 connected to the reduction gear mechanism 4 for manually rotating the output shaft 1. The manual drive mechanism 9 is configured to be switchable between a connected state in which it is connected to the reduction gear mechanism 4 and a disconnected state in which it is not connected to the reduction gear mechanism 4. Thus, by providing the manual drive mechanism 9, fine adjustments of the rotation of the electric actuator 100 can be easily performed manually during assembly, rotation, and the like. Furthermore, because the manual drive mechanism 9 is configured to be switchable between a connected state in which it is connected to the reduction gear mechanism 4 and a disconnected state in which it is not connected to the reduction gear mechanism 4, the manual drive mechanism 9 can be connected by switching to the connected state during manual driving, thereby enabling stable manual driving. Furthermore, when driven by the electric motor 2, the manual drive mechanism 9 can be disconnected by switching to the disconnected state, thereby preventing an increase in the power of the electric motor 2 due to friction in the manual drive mechanism 9.

[0055] Furthermore, in the first embodiment, as described above, the manual drive mechanism 9 includes the moving part 91 having at one end a speed reduction mechanism engaging part 91a that engages with the speed reduction mechanism 4 and at the other end a tool engaging part 91b that engages with a manual operation tool, and the biasing part 92 that biases the moving part 91 so as to move between a connected state and a disconnected state. As a result, the manual drive mechanism 9 can be switched between the connected state and the disconnected state simply by moving the moving part 91 with the biasing part 92, and therefore the manual drive mechanism 9 can be switched between the connected state and the disconnected state with a relatively simple structure.

[0056] Furthermore, in the first embodiment, as described above, the electric motor 2 includes the motor core 21, and the motor core 21 is disposed within the housing 7 without having a dedicated motor housing. This allows the electric motor 2 to be easily disposed within the housing 7, unlike when the electric motor 2 has a dedicated motor housing, and therefore the housing 7 can be easily made smaller. As a result, the electric actuator 100 can be easily made smaller.

[0057] Furthermore, in the first embodiment, as described above, the electric actuator 100 is provided with an overload limiting mechanism 8 that is disposed in the housing 7 between the output shaft 1 and the electric motor 2 and that prevents torque overload. As a result, even if a torque overload occurs due to, for example, a sudden stop of the electric motor 2, the torque overload can be prevented by the overload limiting mechanism 8, and therefore it is not necessary to design the driving elements of the electric actuator 100, such as the reduction mechanism 4, to withstand torque overload. As a result, the weight of the driving elements of the electric actuator 100 can be reduced compared to when the driving elements of the electric actuator 100 are designed to withstand torque overload.

[0058] In the first embodiment, as described above, the overload limiting mechanism 8 is a slip clutch that avoids torque overload by causing slippage when a specified torque is reached. As a result, when the specified torque is reached, the overload limiting mechanism 8 causes slippage, making it possible to easily and reliably avoid torque overload.

[0059] Furthermore, in the first embodiment, as described above, the electric actuator 100 is configured to drive the flaps of the aircraft, which allows the electric actuator 100 for driving the flaps of the aircraft to be easily replaced.

[0060] [Second embodiment] Next, a second embodiment of the present invention will be described with reference to Fig. 4. In the second embodiment, an example in which a ball screw is an output object will be described. Note that the same components as those in the first embodiment will be given the same reference numerals, and their description will be omitted.

[0061] (Electric actuator configuration) 4, the electric actuator 200 includes an output shaft 1, an electric motor 2, a controller 3, a reduction mechanism 4 (a first spur gear reduction mechanism 41, a second spur gear reduction mechanism 42, and a planetary gear reduction mechanism 43), a position sensor 6, a housing 7, an overload limiting mechanism 8, a manual drive mechanism 9, and a through shaft 10. The electric actuator 200 also includes a non-reversible mechanism 205 instead of the non-reversible mechanism 5, and does not include the trochoid gear reduction mechanism 44.

[0062] A ball screw 301, which serves as an output target, is attached to the output shaft 1 of the electric actuator 200 by a fastening member 302 such as a bolt. The output shaft 1 is configured to rotate about a rotation axis C1, thereby causing the ball screw 301 to rotate about the rotation axis C1. This allows the electric actuator 200 to function as a linear motion mechanism using the ball screw 301 and a ball nut 303 connected to the ball screw 301. The ball screw 301 can be separated from the output shaft 1 by removing the fastening member 302.

[0063] In the second embodiment, the housing 7 integrally includes the output shaft 1, the electric motor 2, the controller 3, the reduction mechanism 4 (first spur gear reduction mechanism 41, second spur gear reduction mechanism 42, and planetary gear reduction mechanism 43), the non-reversible mechanism 205, the position sensor 6, the overload limiting mechanism 8, the manual drive mechanism 9, and the through shaft 10, and is configured to be attachable and detachable to the mounting object independently of the ball screw 300 as the output object.

[0064] Moreover, in the second embodiment, the irreversible mechanism 205 is a friction plate type irreversible mechanism. In the friction plate type irreversible mechanism 205, when backdrive torque acts as an axial force from the ball nut 303, the axial force presses the friction plates (205a), generating a brake torque. Specifically, the irreversible mechanism 205 includes a plurality of friction plates 205a. When the axial force from the ball nut 303 acts, the plurality of friction plates 205a are pressed together so that their friction surfaces come into close contact with each other in the X direction, thereby generating a brake torque. Moreover, the irreversible mechanism 205 is connected to the planetary gear reduction mechanism 43 on the input side and to the output shaft 1 on the output side. Note that the electric actuator 200 may be provided with a non-reversible mechanism 5 instead of the non-reversible mechanism 205.

[0065] The other configurations of the second embodiment are the same as those of the first embodiment.

[0066] (Effects of the second embodiment) In the second embodiment, the following effects can be obtained.

[0067] In the second embodiment, as described above, the electric actuator 100 comprises an output shaft 1 that outputs a rotational force to an output target, an electric motor 2 that rotates the output shaft 1, a controller 3 that controls the electric motor 2, a reduction mechanism 4 arranged between the output shaft 1 and the electric motor 2, a non-reversible mechanism 205 arranged between the output shaft 1 and the electric motor 2 that prevents backdrive torque from the output side from being transmitted to the input side, a position sensor 6 that detects the rotational position of the output shaft 1, and a housing 7 in which the output shaft 1, the electric motor 2, the controller 3, the reduction mechanism 4, the non-reversible mechanism 205, and the position sensor 6 are arranged, and which is attachable to and detachable from the mounting target independently of the output target.

[0068] As a result, similar to the first embodiment, even when it is desired to replace the electric actuator 200 independently of the object to which the rotational force is output, the electric actuator 200 can be easily replaced.

[0069] The other effects of the second embodiment are the same as those of the first embodiment.

[0070] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than the above description of the embodiments, and further includes all modifications (variations) within the meaning and scope of the claims.

[0071] For example, in the above first and second embodiments, an example was shown in which the electric actuator was applied to the drive system of an aircraft flap, but the present invention is not limited to this. In the present invention, the electric actuator may also be applied to the drive systems of aircraft equipment other than aircraft flaps (such as flight control devices, landing gear, and cargo door operating devices). Furthermore, the electric actuator of the present invention may also be applied to fields other than the aviation field. For example, the electric actuator of the present invention can be applied to the drive systems of the joints of various precision robots, the drive systems of construction machinery arms used in civil engineering and construction, the drive systems of wheels and fittings of precision agricultural equipment, the drive systems of automatic door operating devices for building fixtures, the drive systems of general industrial machinery, electric winches, hoists, and elevators, and the drive systems of actuation devices for interactive games at entertainment facilities.

[0072] In addition, although the first embodiment has been described as an example in which four speed reduction mechanisms are provided and the second embodiment has been described as an example in which three speed reduction mechanisms are provided, the present invention is not limited to this. In the present invention, one, two, or five or more speed reduction mechanisms may be provided.

[0073] In the first embodiment, the reduction mechanism includes a spur gear reduction mechanism, a planetary gear reduction mechanism, and a trochoid gear reduction mechanism, and in the second embodiment, the reduction mechanism includes a spur gear reduction mechanism and a planetary gear reduction mechanism, but the present invention is not limited to this. In the present invention, the reduction mechanism may include only one or two of the spur gear reduction mechanism, the planetary gear reduction mechanism, and the trochoid gear reduction mechanism. Furthermore, the reduction mechanism may include a reduction mechanism other than the spur gear reduction mechanism, the planetary gear reduction mechanism, and the trochoid gear reduction mechanism.

[0074] In the first and second embodiments, the output shaft and the electric motor are disposed so that their rotational axes are offset from each other. However, the present invention is not limited to this. In the present invention, the output shaft and the electric motor may be disposed coaxially. In this case, a planetary gear reduction mechanism may be used instead of the spur gear reduction mechanism. However, from the viewpoint of ensuring space for arranging a position sensor, it is preferable that the output shaft and the electric motor be disposed so that their rotational axes are offset from each other.

[0075] Furthermore, in the first and second embodiments, examples have been shown in which a manual drive mechanism is provided, but the present invention is not limited to this, and the present invention does not necessarily require the provision of a manual drive mechanism.

[0076] Furthermore, in the first and second embodiments, an example in which an overload limiting mechanism is provided is shown, but the present invention is not limited to this. In the present invention, an overload limiting mechanism does not necessarily have to be provided.

[0077] In the first and second embodiments, the motor core is disposed in a housing without a dedicated motor housing, but the present invention is not limited to this. In the present invention, the motor core may have a dedicated motor housing.

[0078] In the first and second embodiments, the controller controls the electric motor based on a command signal from a higher-level controller, but the present invention is not limited to this. In the present invention, if there is no higher-level controller, the controller may independently control the electric motor.

[0079] In the first and second embodiments, an example is shown in which a plurality of (two) position sensors are provided to detect the rotational position of the output shaft, but the present invention is not limited to this. In the present invention, one or three or more position sensors may be provided to detect the rotational position of the output shaft.

[0080] In the first and second embodiments, the position sensor that detects the rotational position of the output shaft is disposed on the opposite side of the rotational axis of the output shaft from the electric motor, but the present invention is not limited to this. In the present invention, the position sensor that detects the rotational position of the output shaft may be disposed coaxially with the rotational axis of the output shaft, or may be disposed on the same side of the rotational axis of the output shaft as the electric motor.

[0081] Furthermore, in the first embodiment, an example in which a trochoid gear reduction mechanism is provided has been described, but the present invention is not limited to this. In the present invention, as in a modified example shown in Fig. 5, a 3K type planetary gear reduction mechanism 344 may be provided instead of the trochoid gear reduction mechanism 44. The 3K type planetary gear reduction mechanism 344 is connected to the planetary gear reduction mechanism 43 on the input side and to the output shaft 1 on the output side.

[0082] [Aspect] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0083] (Item 1) an output shaft that outputs a rotational force to an output target; an electric motor that rotates and drives the output shaft; a controller for controlling the electric motor; a reduction mechanism disposed between the output shaft and the electric motor; a non-reversible mechanism disposed between the output shaft and the electric motor, which prevents backdrive torque from being transmitted from the output side to the input side; a position sensor that detects the rotational position of the output shaft; An electric actuator comprising: a housing 7 in which the output shaft, the electric motor, the controller, the reduction mechanism, the non-reversible mechanism, and the position sensor are arranged, and which is detachable from an attachment target independently of the output target.

[0084] (Item 2) Item 2. The electric actuator according to item 1, wherein the speed reduction mechanism includes a plurality of speed reduction mechanisms.

[0085] (Item 3) 3. The electric actuator according to claim 2, wherein the reduction mechanism includes at least two of a trochoid gear reduction mechanism, a planetary gear reduction mechanism, and a spur gear reduction mechanism.

[0086] (Item 4) The output shaft and the electric motor are arranged so that their rotation axes are offset from each other, 4. The electric actuator according to any one of items 1 to 3, wherein the position sensor is disposed on the opposite side of the rotation axis of the output shaft from the electric motor.

[0087] (Item 5) a through shaft connected to the output shaft; Item 5. The electric actuator according to item 4, wherein the position sensor is connected to the through shaft via an anti-backlash gear portion.

[0088] (Item 6) a manual drive mechanism connected to the reduction mechanism for manually rotating the output shaft; The electric actuator according to any one of items 1 to 5, wherein the manual drive mechanism is configured to be switchable between a connected state in which it is connected to the reduction mechanism and a disconnected state in which it is not connected to the reduction mechanism.

[0089] (Item 7) The manual drive mechanism includes: a moving part having a speed reduction mechanism engaging part at one end that engages with the speed reduction mechanism and a tool engaging part at the other end that engages with a manual operation tool; 7. The electric actuator according to claim 6, further comprising: a biasing portion that biases the moving portion so as to be movable so as to switch between the connected state and the disconnected state.

[0090] (Item 8) 8. The electric actuator according to any one of items 1 to 7, wherein the electric motor includes a motor core, and the motor core is disposed in the casing without having a dedicated motor housing.

[0091] (Item 9) 9. The electric actuator according to any one of items 1 to 8, further comprising an overload limiting mechanism disposed in the housing between the output shaft and the electric motor for avoiding torque overload.

[0092] (Item 10) Item 10. The electric actuator according to item 9, wherein the overload limiting mechanism is a slip clutch that avoids the torque overload by causing slippage when a specified torque is reached.

[0093] (Item 11) 11. The electric actuator according to any one of items 1 to 10, configured to drive a flap of an aircraft. [Explanation of symbols]

[0094] 1 output shaft 2 electric motors 3 Controller 4 Reduction mechanism 5, 205 Irreversible mechanism 6 Position Sensors 7. Housing 8. Overload limiting mechanism 9 Manual Drive Mechanism 10 through shaft 41 First spur gear reduction mechanism (spur gear reduction mechanism) 42 Second spur gear reduction mechanism (spur gear reduction mechanism) 43 Planetary gear reduction mechanism 44 Trochoid gear reduction mechanism 61a Anti-backlash gear part 91 Mobile Unit 91a Engagement part for reduction mechanism 91b Tool engagement part 92 energizing section 100, 200 Electric Actuator 344 3K type planetary gear reduction mechanism (planetary gear reduction mechanism)

Claims

1. an output shaft that outputs a rotational force to an output target; an electric motor that rotates and drives the output shaft; a controller for controlling the electric motor; a reduction mechanism disposed between the output shaft and the electric motor; a non-reversible mechanism disposed between the output shaft and the electric motor, which prevents backdrive torque from being transmitted from the output side to the input side; a position sensor that detects the rotational position of the output shaft; a housing in which the output shaft, the electric motor, the controller, the reduction mechanism, the non-reversible mechanism, and the position sensor are arranged, the housing being attachable to and detachable from an attachment target independently of the output target; The output shaft and the electric motor are arranged so that their rotation axes are offset from each other, the controller is disposed on the opposite side of the electric motor with respect to the rotation axis of the output shaft, an electric actuator further including a control cable that is disposed inside the housing in a space formed by arranging the output shaft and the electric motor so that their rotation axes are offset from each other, and that transmits a signal that the controller uses to control the electric motor.

2. The electric actuator according to claim 1 , wherein the speed reducing mechanism includes a plurality of speed reducing mechanisms.

3. The electric actuator according to claim 2 , wherein the reduction mechanism includes at least two of a trochoid gear reduction mechanism, a planetary gear reduction mechanism, and a spur gear reduction mechanism.

4. An electric actuator described in any one of claims 1 to 3, wherein the position sensor is arranged on the opposite side of the electric motor with respect to the rotation axis of the output shaft.

5. a through shaft connected to the output shaft; The electric actuator according to claim 4 , wherein the position sensor is connected to the through shaft via an anti-backlash gear portion.

6. a manual drive mechanism connected to the reduction mechanism for manually rotating the output shaft; The electric actuator according to any one of claims 1 to 5, wherein the manual drive mechanism is configured to be switchable between a connected state in which it is connected to the reduction mechanism and a disconnected state in which it is not connected to the reduction mechanism.

7. The manual drive mechanism includes: a moving part having a speed reduction mechanism engaging part at one end that engages with the speed reduction mechanism and a tool engaging part at the other end that engages with a manual operation tool; The electric actuator according to claim 6, further comprising: a biasing portion that biases the moving portion so as to be movable to switch between the connected state and the disconnected state.

8. The electric actuator according to any one of claims 1 to 7, wherein the electric motor includes a motor core, and the motor core is disposed within the housing without having a dedicated motor housing.

9. The electric actuator according to any one of claims 1 to 8, further comprising an overload limiting mechanism disposed in the housing between the output shaft and the electric motor for avoiding torque overload.

10. 10. The electric actuator according to claim 9, wherein the overload limiting mechanism is a slip clutch that avoids the torque overload by causing slip when a specified torque is reached.

11. The electric actuator according to any one of claims 1 to 10, configured to drive a flap of an aircraft.

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