Robot joint actuator and robot arm comprising same
The innovative design of a robot joint actuator with a fixed shaft and reverse-arranged reduction gear addresses the challenge of cable accommodation and compactness, achieving efficient and accurate rotational motion measurement in a compact form.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SAMSUNG ELECTRONICS CO LTD
- Filing Date
- 2025-11-18
- Publication Date
- 2026-06-18
AI Technical Summary
Existing robot joint actuators face challenges in efficiently accommodating cables while maintaining a compact design and accurate rotational motion measurement, often requiring larger hollows that interfere with operation and complex structures that increase the actuator's diameter.
The design incorporates a fixed shaft within the actuator housing that extends through the input shaft, reduction gear, and output plate, allowing cables to pass through a hollow without additional protective structures, and utilizes a reverse-arranged reduction gear with a hat shape to create a clearance space for bearings and seals, enabling a compact and efficient actuator configuration.
This configuration allows for a compact robot joint actuator that minimizes interference from cables and supports accurate rotational motion measurement, enhancing operational efficiency and reducing the actuator's overall diameter.
Smart Images
Figure KR2025019093_18062026_PF_FP_ABST
Abstract
Description
Robot joint actuator and robot arm including the same
[0001] The present disclosure relates to a robot joint actuator and a robot arm including the same.
[0002] A robotic arm is a mechanical device designed in a form similar to a human arm to perform various movements in a work environment. A robotic arm may include joint actuators that connect links and drive the rotational or linear motion of the links.
[0003] The information described above may be provided as related art for the purpose of aiding understanding of the present disclosure. No claim or determination is made as to whether any of the foregoing may be applied as prior art in relation to the present disclosure.
[0004] In one embodiment, the robot arm may include an actuator housing; a motor disposed within the actuator housing; a reduction gear; an input shaft configured to transmit rotational motion of the motor to the reduction gear; and an output plate configured to rotate by rotational motion transmitted from the reduction gear. Here, the input shaft, the reduction gear, and the output plate may be arranged along an axial direction parallel to the rotation axis of the motor. The robot arm may include a fixed shaft fixedly coupled to the actuator housing and extending along the axial direction through the input shaft, the reduction gear, and the output plate; and an encoder configured to measure one or more parameters associated with the rotational motion of the output plate. The encoder may include a disk coupled to the output plate; and a scanner coupled to the fixed shaft and aligned with the disk.
[0005] According to one embodiment, an actuator of a robot joint may include: an actuator housing; a motor disposed within the actuator housing; a reduction gear; an input shaft configured to transmit rotational motion of the motor to the reduction gear; and an output plate configured to rotate by rotational motion transmitted from the reduction gear. Here, the input shaft, the reduction gear, and the output plate may be arranged along an axial direction parallel to the rotation axis of the motor. The actuator of the robot joint may include a fixed shaft fixedly coupled to the actuator housing and extending along the axial direction through the input shaft, the reduction gear, and the output plate; and an encoder configured to measure one or more parameters associated with the rotational motion of the output plate. The encoder may include a disk coupled to the output plate; and a scanner coupled to the fixed shaft and aligned with the disk.
[0006] FIG. 1 shows a robot arm according to one embodiment.
[0007] FIG. 2 is a block diagram showing an exemplary configuration of an actuator of a robot arm according to one embodiment.
[0008] FIG. 3a is an exploded perspective view of an actuator according to one embodiment.
[0009] FIG. 3b is a cross-sectional view of an actuator according to one embodiment.
[0010] FIG. 4 is a conceptual diagram showing an actuator according to one embodiment.
[0011] Figure 5 shows an actuator according to a comparative example.
[0012] Figure 6 shows an actuator according to a comparative example.
[0013] Identical or similar components in the drawings may be assigned the same reference numerals. Descriptions of components having the same reference numeral may be applied identically or in a corresponding manner when referring to different drawings, unless otherwise noted, and redundant descriptions of components having the same reference numeral may not be repeated. In the following descriptions referring to specific drawings, reference numerals from other drawings may be referenced.
[0014] In describing the present disclosure, if it is determined that a detailed description of related known functions or configurations could unnecessarily obscure the essence of the present disclosure, such detailed description may be abbreviated or omitted.
[0015] FIG. 1 shows a robot arm according to one embodiment.
[0016] In FIG. 1, a robot arm (100) comprising one or more actuators is illustrated as an example. For example, the actuator of the robot arm (100) can form a joint of the two segments by interconnecting the two segments of the robot arm (100). For example, the actuator of the robot arm (100) can provide relative rotational movement of the two segments around at least one axis.
[0017] For example, referring to FIG. 1, a robot arm (100) may include a base (101), a first actuator (102), a first link (103) connected to the base (101) through the first actuator (102), a second actuator (104), a second link (105) connected to the first link (103) through the second actuator (104), a third actuator (106), a third link (107) connected to the second link (105) through the third actuator (106), a fourth actuator (108), and an end-effector (109) connected to the third link (107) through the fourth actuator (108).
[0018] The first actuator (102) can provide relative movement of the first link (103) with respect to the base (101). The second actuator (104) can provide relative movement of the second link (105) with respect to the first link (103). The third actuator (106) can provide relative movement of the third link (107) with respect to the second link (105). The fourth actuator (108) can provide operation of the end effector (109). The end effector (109) is illustrated as a gripper device, but is not limited to the illustrated example.
[0019] Although not illustrated, the robot arm (100) may include a plurality of cables to provide power and control signals to each component. The plurality of cables must be extended so as not to interfere with the operation of the robot arm (100). To this end, the plurality of cables may pass through a hollow formed in the actuator of the robot arm (100). To reduce interference with the operation of the robot arm (100) caused by the cables, an actuator having a larger hollow may be required. An actuator having a larger hollow will be described below.
[0020] FIG. 2 is a block diagram showing an exemplary configuration of an actuator of a robot arm according to one embodiment.
[0021] The actuator (200) shown in FIG. 2 may be an example of the first actuator (102), second actuator (104), third actuator (106), or fourth actuator (108) of FIG. 1.
[0022] Referring to FIG. 2, according to one embodiment, an actuator (200) may include a motor (210), a brake (215), a reduction gear (220), and a single encoder (270) and a single encoder (275). Between the single encoder (270) and the single encoder (275), the reduction gear (220), the motor (210), and the brake (215) may be arranged.
[0023] The motor (210) is a device that provides driving force for the actuator (200). The motor (210) may include, for example, a servo motor, a stepper motor, or a different type of motor. For example, the motor (210) may be connected to a reduction gear (220) and a brake (215) through an input terminal (250). The rotation of the motor (210) may be transmitted to the reduction gear (220) through the input terminal (250).
[0024] The reduction gear (220) is a device that converts the high-speed rotation of the motor (210) to a low speed and outputs high torque. For example, the reduction gear (220) can provide a low-speed, high-torque output through the output terminal (255) by reducing the rotation transmitted through the input terminal (250). The reduction gear (220) may include, for example, a harmonic reduction gear. Although the embodiment of the present disclosure has been described with the harmonic reduction gear as an example, the type of reduction gear (220) is not limited thereto. For example, the reduction gear (220) may include a gear reduction gear or a planetary gear reduction gear.
[0025] A brake (215) is a device used to control or stop rotation provided by an actuator (200). For example, the brake (215) may be connected to an input terminal (250) and configured to control or stop rotation of the input terminal (250). The brake (215) may be placed, for example, between a motor (210) and a single encoder (270). In another example, unlike the illustration, the brake (215) may be placed between a reduction gear (220) and a motor (210).
[0026] A single encoder (270) is a device for detecting the rotational state of an input terminal (250). For example, the single encoder (270) may include a disk (272) and a scanner (274). The disk (272) may be configured to rotate according to the rotation of the input terminal (250). For example, the disk (272) may include a transparent disk or a reflective disk having a readable (e.g., optically readable) pattern formed thereon. The scanner (274) can detect the rotational state (e.g., angular velocity and angular position) of the input terminal (250) by reading the disk (272) which rotates according to the rotation of the input terminal (250). For example, the scanner (274) may receive an optical signal that passes through or is reflected by the disk (272) and output a signal modulated according to the pattern of the disk (272). The modulation signal output from the scanner (274) can be interpreted by a controller (not shown) of the actuator (200).
[0027] A single encoder (275) is a device for detecting the rotational state of an output terminal (255). For example, the single encoder (275) may include a disk (276) and a scanner (278). The disk (276) may be configured to rotate according to the rotation of the output terminal (255). For example, the disk (276) may include a transparent disk or a reflective disk having a readable (e.g., optically readable) pattern formed thereon. The scanner (278) can detect the rotational state (e.g., angular velocity and angular position) of the output terminal (255) by reading the disk (276) which rotates according to the rotation of the output terminal (255). For example, the scanner (278) may receive an optical signal that passes through or is reflected by the disk (276) and output a signal modulated according to the pattern of the disk (276). The modulation signal output from the scanner (278) can be interpreted by the controller (not shown) of the actuator (200).
[0028] FIG. 3a is an exploded perspective view of an actuator according to one embodiment. FIG. 3b is a cross-sectional view of an actuator according to one embodiment. The cross-sectional view of FIG. 3b may be a cross-section cut along a plane including the operating axis of the actuator (300).
[0029] In FIG. 3a and FIG. 3b, a first axial direction (A1) and a second axial direction (A2) are defined. The first axial direction (A1) and the second axial direction (A2) may be parallel to each other. The first axial direction (A1) may be the opposite direction to the second axial direction (A2). For example, the first axial direction (A1) and the second axial direction (A2) may be parallel to the axis of motion of the actuator (300). For example, the first axial direction (A1) and the second axial direction (A2) may be parallel to the axis of rotation of the output plate (355) of the actuator (300). For example, the first axial direction (A1) and the second axial direction (A2) may be parallel to the axis of rotation of the input shaft (350) of the actuator (300).
[0030] The actuator (300) of FIGS. 3a and FIGS. 3b may be an example of the actuator (200) of FIG. 2.
[0031] Referring to FIGS. 3a and 3b, according to one embodiment, an actuator (300) may include a motor (310) (e.g., motor (210) of FIG. 2), a brake (315) (e.g., brake (215) of FIG. 2), a reduction gear (320) (e.g., reduction gear (220) of FIG. 2), and an input encoder (370) (e.g., single encoder (270) of FIG. 2) and an output encoder (375) (e.g., single encoder (275) of FIG. 2).
[0032] According to one embodiment, the actuator (300) may include an input shaft (350) (e.g., input end (250) of FIG. 2) that transmits the output of the motor (310) to the reduction gear (320) and an output plate (355) (e.g., output end (255) of FIG. 2) to which the output of the reduction gear (320) is transmitted. A segment of the robot arm (100) (e.g., first link (103), second link (105), or third link (107) of FIG. 1) to be driven through the actuator (300) may be coupled to the output plate (355).
[0033] The actuator (300) may include an actuator housing (305) that forms at least a portion of the exterior of the actuator (300). The actuator housing (305) may include a first part (301), a second part (302) coupled to the first part (301), and a third part (303) coupled to the second part (302). The second part (302) may be located between the first part (301) and the third part (303). For example, the second part (302) may be located in the first axial direction (A1) of the first part (301), and the third part (303) may be located in the first axial direction (A1) of the second part (302).
[0034] The actuator (300) may include a fixed shaft (360). The fixed shaft (360) may be fixedly coupled to the actuator housing (305). For example, the fixed shaft (360) may be fixedly coupled to a first part (301) of the actuator housing (305). The fixed shaft (360) may extend from the first part (301) in a first axial direction (A1). For example, the fixed shaft (360) may pass through an input shaft (350), a reduction gear (320), and the output plate (355).
[0035] The fixed shaft (360) may include a hollow (365). Although not illustrated, cables of the robot arm (100) may pass through the hollow (365) of the fixed shaft (360). Since the fixed shaft (360) is fixed to the actuator housing (305) and does not rotate, a protective member, such as a protective jacket for cables passing through the hollow (365), may not be required.
[0036] The fixed shaft (360) may include a first end (361) facing the second axial direction (A2) and a second end (362) facing the first axial direction (A1). The first end (361) of the fixed shaft (360) may be fixedly coupled to the first part (301) of the actuator housing (305). The second end (362) of the fixed shaft (360) may protrude out of the output plate (355). For example, the second end (362) of the fixed shaft (360) may be located in the first axial direction (A1) of the output plate (355). A scanner (378) of the output encoder (375) may be fixedly positioned at the second end (362) of the fixed shaft (360).
[0037] The motor (310) may be disposed within the actuator housing (305). The motor (310) may include a stator (312) and a rotor (314) disposed within a central opening formed in the stator (312). The stator (312) may be fixed to the actuator housing (305), and the rotor (314) may be configured to rotate relative to the stator (312). The rotation axis of the rotor (314) may be parallel to the first axial direction (A1) and the second axial direction (A2).
[0038] The input shaft (350) may be coupled to the rotor (314) of the motor (310). For example, the input shaft (350) may include a first section coupled to the rotor (314) of the motor (310), a second section extending in a first axial direction (A1) from the first section to the reduction gear (320), and a third section extending in a second axial direction (A2) from the first section. The input shaft (350) may rotate according to the rotation of the rotor (314). The input shaft (350) may transmit the rotational motion of the motor (310) to the reduction gear (320). A hollow may be formed in the input shaft (350), which is penetrated by a fixed shaft (360).
[0039] The input shaft (350) may include a first part coupled to the wave generator (330) of the reduction gear (320), a second part coupled to the disk (372) of the input encoder (370), and a third part located between the first part and the second part and coupled to the rotor (314) of the motor (310). Additionally, the input shaft (350) may include a fourth part located between the second part and the third part. A bearing (383) may be disposed between the fourth part of the input shaft (350) and the part of the actuator housing (305). Additionally, the input shaft (350) may include a fifth part located between the first part and the third part. An oil seal (392) may be disposed between the fifth part of the input shaft (350) and the other part of the actuator housing (305).
[0040] A reduction gear (320) may be positioned between an input shaft (350) and an output plate (355). The reduction gear (320) may reduce the speed of rotation transmitted from the input shaft (350) and increase the torque to provide to the output plate (355). A hollow may be formed in the reduction gear (320) through which a fixed shaft (360) passes.
[0041] The reduction gear (320) may include a circular spline (345) fixedly coupled to an actuator housing (305), a flex spline (340) configured to mesh with the circular spline (345), and a wave generator (330) configured to deform the flex spline (340).
[0042] On the inner surface of the circular spline (345) and the outer surface of the flex spline (340), teeth of gears that mesh with each other may be formed. For example, the number of teeth of the circular spline (345) may be greater than the number of teeth of the flex spline (340). When the wave generator (330) rotates in accordance with the rotation of the input shaft (350), the flex spline (340) may be deformed. As the flex spline (340) is deformed, the position in which the teeth of the flex spline (340) mesh with the teeth of the circular spline (345) may change. Because the number of teeth of the flex spline (340) is less than the number of teeth of the circular spline (345), the flex spline (340) may rotate more slowly than the wave generator (330). The flex spline (340) can be coupled to the output plate (355). Accordingly, the output plate (355) can rotate at a slower speed and higher torque than the output of the motor (310).
[0043] The wave generator (330) may include a coupling portion (332) and a sleeve portion (334). The coupling portion (332) may be configured to engage with a flex spline (340). The sleeve portion (334) may extend from the coupling portion (332) toward an output plate (355) (e.g., in the first axial direction (A1)) and be spaced apart from the flex spline (340).
[0044] The output plate (355) may be configured to rotate by rotational motion transmitted from the reduction gear (320). The input shaft (350), the reduction gear (320), and the output plate (355) may be arranged along a first axial direction (A1). For example, in the first axial direction (A1), the reduction gear (320) may be positioned between the output plate (355) and the input shaft (350).
[0045] The output plate (355) may include a plate portion (356) and a sleeve portion (358). The plate portion (356) may be connected to the flex spline (340). The sleeve portion (358) may extend from the plate portion (356) in a second axial direction (A2). The sleeve portion (358) of the output plate (355) may be positioned between the flex spline (340) and the sleeve portion (334) of the wave generator (330) so as to be spaced apart from the flex spline (340) and the wave generator (330).
[0046] The actuator (300) may include a bearing (381) interposed between the sleeve portion (334) of the wave generator (330) and the sleeve portion (358) of the output plate (355). The bearing (381) may support rotation of the output plate (355).
[0047] The actuator (300) may include an oil seal (391) interposed between the sleeve portion (334) of the wave generator (330) and the sleeve portion (358) of the output plate (355). The oil seal (391) may be located between the plate portion (356) of the output plate (355) and the bearing (381).
[0048] A hole may be formed in the plate portion (356) of the output plate (355) through which a fixed shaft (360) passes. The actuator (300) may include a bearing (382) interposed between the inner surface of the hole in the plate portion (356) and the outer surface of the fixed shaft (360) to support the rotational movement of the output plate (355).
[0049] The actuator (300) may include a bearing (383) interposed between a part of the input shaft (350) and a part of the actuator housing (305) (e.g., a second part (302)) to support the rotational movement of the input shaft (350). For example, the bearing (383) may be located between the motor (310) and the brake (315) in a first axial direction (A1) or a second axial direction (A2).
[0050] The actuator (300) may include an oil seal (392) interposed between another part of the input shaft (350) and another part of the actuator housing (305) (e.g., a third part (303)). In the first axial direction (A1) or the second axial direction (A2), the oil seal (392) may be located between the wave generator (330) and the motor (310). In the first axial direction (A1) or the second axial direction (A2), the coupling part (332) of the wave generator (330) may be located between the oil seal (392) and the bearing (381). In the first axial direction (A1) or the second axial direction (A2), the rotor (314) of the motor (310) may be located between the oil seal (392) and the bearing (383).
[0051] The input encoder (370) may be configured to measure one or more parameters associated with the rotational motion of the motor (310) (or input shaft (350)). For example, the input encoder (370) may include a disk (372) (e.g., disk (272) in FIG. 2) coupled to the input shaft (350) and a scanner (374) (e.g., scanner (274) in FIG. 2) fixedly positioned in the actuator housing (305) to face the disk (372). For example, the disk (372) may be coupled to the end of the input shaft (350) facing the second axial direction (A2). The scanner (374) may be fixedly positioned in the first part (301) of the actuator housing (305) to face the disk (372). The disk (372) can rotate relative to the scanner (374) according to the rotation of the input shaft (350). The scanner (374) facing the disk (372) can detect information about the rotation of the disk (372).
[0052] The output encoder (375) may be configured to measure one or more parameters associated with the rotational motion of the output plate (355). For example, the output encoder (375) may include a disk (376) coupled to the output plate (355) (e.g., disk (276) in FIG. 2) and a scanner (378) fixedly positioned on a fixed shaft (360) to face the disk (376) (e.g., scanner (278) in FIG. 2). For example, the disk (376) may be positioned on the plate portion (356) of the output plate (355). The scanner (378) may be fixedly coupled to a second end (362) of the fixed shaft (360) facing the first axial direction (A1). The disk (376) may rotate relative to the scanner (378) according to the rotation of the output plate (355). A scanner (378) facing the disk (376) can detect information about the rotation of the disk (376).
[0053] In the first axial direction (A1) or the second axial direction (A2), the motor (310) may be located between the input encoder (370) and the output encoder (375). In the first axial direction (A1) or the second axial direction (A2), the reduction gear (320) may be located between the input encoder (370) and the output encoder (375). The reduction gear (320) may be arranged such that the circular spline (345) faces the second axial direction (A2) and the flex spline (340) faces the first axial direction (A1). For example, the flex spline (340) may include a portion located between the output plate (355) and the circular spline (345) in the first axial direction (A1) or the second axial direction (A2), as in portion (342) of FIG. 3b.
[0054] In the comparative example, a dual encoder structure in which the input encoder and output encoder are positioned to be offset to one side may be applied. In this case, for the output encoder to detect rotation information of the output plate, the flex spline must extend through the hollow of the wave generator to where the output encoder is located. To this end, in the comparative example, the reduction gear may be positioned in a direction symmetrical to the left and right of the reduction gear (320) of the illustrated example (e.g., unlike the illustration, the circular spline (345) faces the first axial direction (A1) and the flex spline (340) faces the second axial direction (A2)). However, since such a comparative example includes a structure in which the flex spline for the output encoder unnecessarily extends in the opposite direction to the output end and a structure that supports their rotation, it may be difficult to reduce the inner diameter of the actuator.
[0055] In contrast, according to one embodiment, the reduction gear (320) may have a structure arranged in the reverse direction compared to the comparative example described above. For example, the reduction gear (320) may have a hat shape when viewed from the side (e.g., when viewed in a direction perpendicular to the first axial direction (A1) or the second axial direction (A2). The hat shape of the reduction gear (320) may include a lower portion and an upper portion that is narrower than the lower portion. The upper portion and the lower portion of the hat shape of the reduction gear (320) may be coaxially aligned in the first axial direction (A1) or the second axial direction (A2). The reduction gear (320) may have a structure in which the upper portion of the hat shape faces the second axial direction (A2) and the lower portion of the hat shape faces the first axial direction (A1). A coupling portion (332) of a wave generator (330) connected to an input shaft (350) may be located at the upper portion of the hat shape. Accordingly, a clearance space may be formed inside the flex spline (340) of the reduction gear (320). A bearing (381) and an oil seal (391) may be placed within this clearance space. Additionally, the size of the internal hollow (e.g., hollow (365)) of the actuator (300) can be easily expanded by this clearance space.
[0056] FIG. 4 is a conceptual diagram showing an actuator according to one embodiment.
[0057] Referring to FIG. 4, according to one embodiment, an actuator (400) (e.g., actuator (300) of FIG. 3a and FIG. 3b) may include a housing (405) (e.g., actuator housing (305) of FIG. 3a and FIG. 3b), a fixed shaft (460) (e.g., fixed shaft (360) of FIG. 3a and FIG. 3b), and an encoder (475) (e.g., output encoder (375) of FIG. 3a and FIG. 3b).
[0058] The fixed shaft (460) may be cantilevered in the housing (405). The encoder (475) may include a disk (476) configured to rotate by the operation of the actuator (400) (e.g., disk (376) in FIG. 3a and FIG. 3b) and a scanner (478) fixedly positioned at the open end of the fixed shaft (460) to face the disk (476) (e.g., scanner (378) in FIG. 3a and FIG. 3b).
[0059] Figure 5 shows an actuator according to a comparative example.
[0060] Referring to FIG. 5, the actuator according to the comparative example may include a housing (505), a scanner (578) of an encoder, and a disk (576) of an encoder. The actuator according to the comparative example may not include a fixed shaft (e.g., the fixed shaft (460) of FIG. 4) located inside the housing (505) to fixedly support the scanner (578). Accordingly, the actuator according to the comparative example may include a separate structure (560) installed outside the housing (505) to fixedly support the scanner (578). If the structure (560) is present, rotation of the link of the robot arm driven by the actuator may be impossible. That is, the actuator according to the comparative example, which includes the structure (560) instead of the fixed shaft (460), may not be implementable.
[0061] Figure 6 shows an actuator according to a comparative example.
[0062] Referring to FIG. 6, the actuator according to the comparative example may include a housing (605), an encoder scanner (678), and an encoder disk (676). The actuator according to the comparative example may not include a fixed shaft (e.g., the fixed shaft (460) of FIG. 4) located inside the housing (605) to fix and support the scanner (678). Therefore, the actuator according to the comparative example may include a separate structure (660) installed outside the housing (605) to fix and support the scanner (678). However, since the scanner (678) and the disk (676) constitute a drum-type encoder, rotation of the link of the robot arm may be possible even if the actuator according to the comparative example includes the structure (660). However, due to the drum-type encoder, the outer diameter of the actuator itself may increase, and the structure may become complex.
[0063] The technical problems to be solved in this disclosure are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure pertains.
[0064] In one embodiment, the robot arm (100) may include an actuator housing (305); a motor (310) disposed within the actuator housing (305); a reduction gear (320); an input shaft (350) configured to transmit the rotational motion of the motor (310) to the reduction gear (320); and an output plate (355) configured to rotate by the rotational motion transmitted from the reduction gear (320). Here, the input shaft (350), the reduction gear (320), and the output plate (355) may be arranged along an axial direction (A1; A2) parallel to the rotation axis of the motor (310). The robot arm (100) may include a fixed shaft (360) that is fixedly coupled to the actuator housing (305) and extends along the axial direction (A1; A2) through the input shaft (350), the reduction gear (320), and the output plate (355); and an encoder (375) configured to measure one or more parameters associated with the rotational movement of the output plate (355). The encoder (375) may include a disk (376) coupled to the output plate (355); and a scanner (378) coupled to the fixed shaft (360) and aligned with the disk (376).
[0065] In one embodiment, the robot arm (100) may include one or more cables. The one or more cables may pass through a hollow (365) formed within the fixed shaft (360).
[0066] In one embodiment, the reduction gear (320) may include a circular spline (345) fixedly coupled to the actuator housing (305); and a flex spline (340) configured to mesh with the circular spline (345). The flex spline (340) may include a portion (342) located between the output plate (355) and the circular spline (345) in the axial direction (A1; A2).
[0067] In one embodiment, the reduction gear (320) may have a substantial hat shape when viewed in a direction perpendicular to the axial direction (A1; A2). The hat shape may include an upper portion and a lower portion that is wider than the upper portion. The upper portion of the hat shape may face the direction of the motor (310), and the lower portion of the hat shape may face the direction of the output plate (355).
[0068] In one embodiment, the reduction gear (320) may include a wave generator (330) configured to deform the flex spline (340). The wave generator (330) may include a coupling portion (332) configured to engage with the flex spline (340); and a sleeve portion (334) extending from the coupling portion (332) toward the output plate (355) and spaced apart from the flex spline (340). The output plate (355) includes a plate portion (356) coupled to the flex spline (340) and to which the disk (376) of the encoder (375) is coupled; and may include a sleeve portion (358) extending from the plate portion (356) toward the wave generator (330) and located at least partially between the sleeve portion (334) of the wave generator (330) and the flex spline (340). The robot arm (100) may include a bearing (381) interposed between the sleeve portion (334) of the wave generator (330) and the sleeve portion (358) of the output plate (355).
[0069] In one embodiment, the robot arm (100) may include an oil seal (391) interposed between the sleeve portion (334) of the wave generator (330) and the sleeve portion (358) of the output plate (355). The oil seal (391) may be located between the plate portion (356) of the output plate (355) and the bearing (381).
[0070] In one embodiment, a hole through which the fixed shaft (360) passes may be formed in the plate portion (356). The robot arm (100) may include another bearing (382) interposed between the inner surface of the hole in the plate portion (356) and the outer surface of the fixed shaft (360) to support the rotational movement of the output plate (355).
[0071] In one embodiment, the robot arm (100) may include another encoder (370) configured to measure one or more parameters associated with the rotational motion of the motor (310). The motor (310) may be located between the encoder (375) and the other encoder (370) in the axial direction (A1; A2).
[0072] In one embodiment, the input shaft (350) may include a first part coupled to the reduction gear (320); a second part coupled to the disk (372) of the other encoder (370); and a third part located between the first part and the second part and coupled to the rotor (314) of the motor (310).
[0073] In one embodiment, the scanner (374) of the other encoder (370) may be fixedly positioned within the actuator housing (305) so as to face the disk (372) of the other encoder (370).
[0074] In one embodiment, the input shaft (350) may include a fourth portion located between the second portion and the third portion. The robot arm (100) may include a bearing (383) interposed between the fourth portion of the input shaft (350) and a portion of the actuator housing (305) to support the rotational movement of the input shaft (350).
[0075] In one embodiment, the input shaft (350) may include a fifth portion located between the first portion and the third portion. The robot arm (100) may include an oil seal (392) interposed between the fifth portion of the input shaft (350) and another portion of the actuator housing (305).
[0076] In one embodiment, the fixed shaft (360) may include a first end (361) coupled to the actuator housing (305); and a second end (362) opposite to the first end (361) in the axial direction (A1; A2) and protruding out of the output plate (355). The scanner (378) of the encoder (375) may be coupled to the second end (362) of the fixed shaft (360).
[0077] In one embodiment, the robot arm (100) may include a base (101); an actuator (102; 300) coupled to the base (101), comprising the actuator housing (305), the motor (310), the reduction gear (320), the input shaft (350), the output plate (355), the fixed shaft (360), and the encoder (375); and a link (103) coupled to the output plate (355) of the actuator (300).
[0078] According to one embodiment, an actuator (300) of a robot joint may include: an actuator housing (305); a motor (310) disposed within the actuator housing (305); a reduction gear (320); an input shaft (350) configured to transmit rotational motion of the motor (310) to the reduction gear (320); and an output plate (355) configured to rotate by rotational motion transmitted from the reduction gear (320). Here, the input shaft (350), the reduction gear (320), and the output plate (355) may be arranged along an axial direction (A1; A2) parallel to the rotation axis of the motor (310). The actuator (300) of the robot joint may include a fixed shaft (360) that is fixedly coupled to the actuator housing (305) and extends along the axial direction (A1; A2) through the input shaft (350), the reduction gear (320), and the output plate (355); and an encoder (375) configured to measure one or more parameters associated with the rotational movement of the output plate (355). The encoder (375) may include a disk (376) coupled to the output plate (355); and a scanner (378) coupled to the fixed shaft (360) and aligned with the disk (376).
[0079] In one embodiment, a through hole (365) extending in the axial direction (A1; A2) may be formed in the fixed shaft (360).
[0080] In one embodiment, the reduction gear (320) may include a circular spline (345) fixedly coupled to the actuator housing (305); and a flex spline (340) configured to mesh with the circular spline (345). The flex spline (340) may include a portion (342) located between the output plate (355) and the circular spline (345) in the axial direction (A1; A2).
[0081] In one embodiment, the reduction gear (320) may have a substantial hat shape when viewed in a direction perpendicular to the axial direction (A1; A2). The hat shape may include an upper portion and a lower portion that is wider than the upper portion. The upper portion of the hat shape may face the direction of the motor (310), and the lower portion of the hat shape may face the direction of the output plate (355).
[0082] In one embodiment, the actuator (300) may include another encoder (370) configured to measure one or more parameters associated with the rotational motion of the motor (310). The motor (310) may be located between the encoder (375) and the other encoder (370) in the axial direction (A1; A2).
[0083] In one embodiment, the input shaft (350) may include a first part coupled to the reduction gear (320); a second part coupled to the disk (372) of the other encoder (370); and a third part located between the first part and the second part and coupled to the rotor of the motor (310).
[0084] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs.
[0085] The various embodiments of this document and the terms used therein are not intended to limit the technical features described in this document to specific embodiments, and should be understood to include various modifications, equivalents, or substitutions of said embodiments. In connection with the description of the drawings, similar reference numerals may be used for similar or related components. The singular form of a noun corresponding to an item may include one or more of said items unless the relevant context clearly indicates otherwise. In this document, each of phrases such as "A or B," "at least one of A and B," "at least one of A or B," "A, B or C," "at least one of A, B and C," and "at least one of A, B, or C" may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof. Terms such as "first," "second," or "first" or "second" may be used simply to distinguish a component from another component and do not limit the components in any other aspect (e.g., importance or order). Where any component (e.g., the first) is referred to as "coupled" or "connected" to another component (e.g., the second), with or without the terms "functionally" or "communicationally," it means that said component may be connected to said other component directly (e.g., via a wire), wirelessly, or through a third component.
[0086] According to various embodiments, each component (e.g., module or program) of the components described above may include a singular or multiple entities, and some of the multiple entities may be separated and placed in other components. According to various embodiments, one or more of the components or operations among the aforementioned components may be omitted, or one or more other components or operations may be added. Generally or additionally, multiple components (e.g., module or program) may be integrated into a single component. In this case, the integrated component may perform one or more functions of each of the multiple components in the same or similar manner as those performed by the corresponding component among the multiple components prior to integration. According to various embodiments, operations performed by the module, program, or other components may be executed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be executed in a different order, omitted, or one or more other operations may be added.
Claims
1. Regarding robot arms, Actuator housing; A motor disposed within the above actuator housing; Reducer; An input shaft configured to transmit the rotational motion of the above motor to the above reduction gear; An output plate configured to rotate by rotational motion transmitted from the reduction gear, wherein the input shaft, the reduction gear, and the output plate are arranged along an axial direction parallel to the rotation axis of the motor; A fixed shaft fixedly coupled to the actuator housing and extending along the axial direction through the input shaft, the reduction gear, and the output plate; and It includes an encoder configured to measure one or more parameters associated with the rotational motion of the output plate, and The above encoder is: A disk coupled to the output plate above; and A scanner coupled to the fixed shaft and aligned with respect to the disk, Robot arm.
2. In Claim 1, Includes one or more cables, The above one or more cables pass through a hollow formed within the fixed shaft, Robot arm.
3. In claim 1 or claim 2, The above reduction gear is: A circular spline fixedly coupled to the actuator housing; and It includes a flex spline configured to mesh with the circular spline above, The above flex spline includes a portion located between the output plate and the circular spline in the axial direction, Robot arm.
4. In Claim 3, The above reduction gear has a substantial cap shape when viewed in a direction perpendicular to the axial direction, The above hat shape includes an upper part and a lower part that is wider than the upper part, and The upper part of the hat shape faces the direction of the motor, and the lower part of the hat shape faces the direction of the output plate. Robot arm.
5. In claim 3 or claim 4, The above reduction gear is, It includes a wave generator configured to deform the above flex spline, and The above wave generator is: A coupling portion configured to engage with the above-mentioned flex spline; and It includes a sleeve portion extending from the above-mentioned coupling portion toward the output plate and spaced apart from the flex spline, The above output plate is: A plate portion coupled to the flex spline and coupled to the disk of the encoder; and It includes a sleeve portion extending from the plate portion toward the wave generator and located at least partially between the sleeve portion of the wave generator and the flex spline, The robot arm comprises a bearing interposed between the sleeve portion of the wave generator and the sleeve portion of the output plate. Robot arm.
6. In Claim 5, It includes an oil seal interposed between the sleeve portion of the wave generator and the sleeve portion of the output plate, and The above oil seal is located between the plate portion of the output plate and the bearing, Robot arm.
7. In Claim 6, A hole is formed in the above plate portion through which the above fixed shaft passes, and The robot arm includes another bearing interposed between the inner surface of the hole of the plate portion and the outer surface of the fixed shaft to support the rotational movement of the output plate. Robot arm.
8. In any one of claims 1 to 7, It includes another encoder configured to measure one or more parameters associated with the rotational motion of the motor, and The above motor is located between the encoder and the other encoder in the above axial direction, Robot arm.
9. In Claim 8, The above input shaft is: A first part coupled to the above reduction gear; A second part to which the disk of the other encoder is combined; and A third part comprising a portion located between the first part and the second part and coupled to the rotor of the motor, Robot arm.
10. In Claim 9, The scanner of the other encoder is fixedly positioned within the actuator housing so as to face the disk of the other encoder. Robot arm.
11. In claim 9 or claim 10, The above input shaft includes a fourth part located between the second part and the third part, and The robot arm includes a bearing interposed between the fourth portion of the input shaft and a portion of the actuator housing to support the rotational movement of the input shaft. Robot arm.
12. In any one of claims 9 to 11, The above input shaft includes a fifth part located between the first part and the third part, and The robot arm comprises an oil seal interposed between the fifth portion of the input shaft and another portion of the actuator housing. Robot arm.
13. In any one of claims 1 to 12, The above fixed shaft is: A first end coupled to the actuator housing; and It includes a second end that is opposite to the first end in the above axial direction and protrudes out of the output plate, The scanner of the above encoder is coupled to the second end of the above fixed shaft, Robot arm.
14. In any one of claims 1 to 13, base; An actuator comprising the actuator housing, the motor, the reduction gear, the input shaft, the output plate, the fixed shaft, and the encoder, and coupled to the base; A link comprising a link coupled to the output plate of the above actuator Robot arm.
15. In an actuator of a robot joint, Actuator housing; A motor disposed within the above actuator housing; Reducer; An input shaft configured to transmit the rotational motion of the above motor to the above reduction gear; An output plate configured to rotate by rotational motion transmitted from the reduction gear, wherein the input shaft, the reduction gear, and the output plate are arranged along an axial direction parallel to the rotation axis of the motor; A fixed shaft fixedly coupled to the actuator housing and extending along the axial direction through the input shaft, the reduction gear, and the output plate; and It includes an encoder configured to measure one or more parameters associated with the rotational motion of the output plate, and The above encoder is: A disk coupled to the output plate above; and A scanner coupled to the fixed shaft and aligned with respect to the disk, Actuator.