Hollow planetary deceleration structure, actuator and robot

Abstract

This application relates to a hollow planetary gear reducer structure, actuator, and robot, applicable to the field of robot drive devices. It includes a housing, a primary planetary mechanism, a secondary planetary mechanism, a planet carrier, and a connecting pin. The primary planetary mechanism includes a primary gear ring fixed to the housing and multiple primary planetary gears meshing with it. The secondary planetary mechanism includes a secondary gear ring rotatably mounted to the housing and multiple secondary planetary gears meshing with it. The planet carrier is positioned between the primary and secondary planetary mechanisms and fixed to the motor output shaft. The connecting pin passes through the planet carrier, and the secondary planetary gears are fixed to the primary planetary gears via the connecting pin. This application achieves high torque output through the synergistic design of a two-stage planetary gear transmission structure and an NN-type planetary mechanism, while ensuring the structural strength of the gear set inside the reducer.

Description

Technical Field

[0001] This application relates to the technical field of robot drive devices, and in particular to a hollow planetary deceleration structure, actuator, and robot. Background Technology

[0002] In the field of robot joint actuators, planetary reducers are widely used due to their advantages such as high transmission efficiency and compact structure.

[0003] In related technologies, reducers using single-stage NGW planetary mechanisms have a limited speed ratio range. When high torque is required, the single-stage speed ratio cannot meet the large transmission ratio demand, resulting in insufficient output torque. Although a two-stage planetary mechanism can increase the speed ratio, it will significantly increase the axial dimension of the reducer, making it difficult to adapt to the compact integration requirements of robot joint space.

[0004] Furthermore, the speed ratio of the NGW-type planetary mechanism is strongly correlated with the center distance design. When the speed ratio needs to be increased, the module of the sun gear and planet gears is forced to decrease, resulting in a significant increase in tooth surface contact stress and tooth root bending stress, which reduces the gear load-bearing capacity and fails to meet the strength requirements for long-term reliable operation of robot joints. Utility Model Content

[0005] Therefore, it is necessary to provide a hollow planetary reduction structure, actuator, and robot to address the problem of balancing high torque output, compact structure, and gear strength in related technologies.

[0006] In a first aspect, this application provides a hollow planetary deceleration structure, which adopts the following technical solution:

[0007] A hollow planetary speed reducer structure includes a housing, a primary planetary mechanism, a secondary planetary mechanism, a planet carrier, and a connecting pin. The primary planetary mechanism includes a primary ring gear and a plurality of primary planetary gears meshing with the primary ring gear, and the primary ring gear is fixed to the housing. The secondary planetary mechanism includes a secondary ring gear and a plurality of secondary planetary gears meshing with the secondary ring gear, and the secondary ring gear is rotatably mounted on the housing. The planet carrier is disposed between the primary and secondary planetary mechanisms, and the planet carrier can be coaxially fixed to the output shaft of a motor. The connecting pin passes through the planet carrier, and the secondary planetary gears are fixed one-to-one with the primary planetary gears by means of the connecting pin.

[0008] In one embodiment, the hollow planetary reduction structure further includes a positioning bearing disposed between the secondary gear ring and the housing, for rotatably mounting the secondary gear ring onto the housing.

[0009] In one embodiment, the planetary carrier has a connecting hole at its axis, the connecting hole being used for the output shaft of the motor to pass through.

[0010] In one embodiment, the planet carrier includes a plurality of through holes spaced apart circumferentially along the planet carrier, and the connecting pins are respectively inserted through the through holes.

[0011] In one embodiment, the hollow planetary reduction structure further includes a connector. The secondary gear ring has a mounting groove on its end face opposite to the planet carrier. The connector is accommodated in the mounting groove and is drively connected to the planet carrier, and is rotatable relative to the secondary gear ring.

[0012] Secondly, this application provides an actuator, which adopts the following technical solution:

[0013] An actuator includes a motor and the aforementioned hollow planetary reduction gear structure. The motor includes a stator, a rotor, and an output shaft. The output shaft is fixed to the rotor, and the rotor can drive the output shaft to rotate under the drive of the stator. The hollow planetary reduction gear structure is connected to the output shaft.

[0014] In one embodiment, the output shaft has a wiring channel that extends through the output shaft along its axial direction.

[0015] In one embodiment, a first support bearing is further disposed within the housing, the first support bearing being located between the planetary carrier and the housing.

[0016] In one embodiment, a second support bearing is further provided within the housing. Along the axial direction of the output shaft, the second support bearing is arranged opposite to the first support bearing, and the second support bearing is located between the output shaft and the housing.

[0017] Thirdly, this application provides a robot that adopts the following technical solution:

[0018] A robot includes the actuator described above, the actuator serving as a joint of the robot.

[0019] The aforementioned hollow planetary reduction structure achieves high torque output through the coordinated design of a two-stage planetary gear transmission structure and an NN-type planetary mechanism, while ensuring the structural strength of the gear set inside the reducer. Furthermore, the positioning bearing provides both radial and axial support and positioning for the secondary gear ring, achieving an integrated design between the secondary gear ring support structure and the inner ring of the positioning bearing, thereby reducing the axial dimension of the actuator. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the actuator in one embodiment of this application.

[0021] Figure 2 This is a cross-sectional schematic diagram of an actuator in one embodiment of this application.

[0022] Figure 3 This is an exploded view of the actuator in one embodiment of this application.

[0023] Attached image annotations:

[0024] 1. First-stage gear ring; 2. First-stage planetary gear; 3. Second-stage gear ring; 4. Second-stage planetary gear; 5. Connecting pin; 6. Positioning bearing; 7. Planetary carrier; 71. Connecting hole; 72. Through hole; 8. Connecting piece; 81. Mounting slot; 82. Positioning slot; 9. Motor; 91. Stator; 92. Rotor; 93. Output shaft; 931. Wiring channel; 10. Housing; 11. First support bearing; 12. Second support bearing; G1. Central shaft. Detailed Implementation

[0025] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0026] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0027] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0028] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0029] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0030] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0031] In the field of robot joint actuators, planetary reducers are widely used due to their advantages such as high transmission efficiency and compact structure. In the existing technology, reducers using single-stage NGW type planetary mechanisms have the problem of limited speed ratio range. When high torque output is required, the single-stage speed ratio cannot meet the large transmission ratio requirements, resulting in insufficient output torque. Although using a two-stage planetary mechanism can increase the speed ratio, it will significantly increase the axial dimension of the reducer, making it difficult to meet the compact integration requirements of robot joint space.

[0032] Furthermore, the speed ratio of the NGW-type planetary mechanism is strongly correlated with the center distance design. When the speed ratio needs to be increased, the module of the sun gear and planet gears is forced to decrease, resulting in a significant increase in tooth surface contact stress and tooth root bending stress, which reduces the gear load-bearing capacity and fails to meet the strength requirements for long-term reliable operation of robot joints.

[0033] In summary, existing technologies present certain contradictions in balancing high torque output, compact structure, and gear strength, necessitating a planetary reduction scheme that can both expand the speed ratio range and optimize structural dimensions and load-bearing capacity. The following, in conjunction with the appendix... Figure 1-3 The embodiments of this application will be described in further detail.

[0034] See Figure 1 , Figure 1 A schematic diagram of the actuator in one embodiment of this application is shown. Figure 2 A cross-sectional schematic diagram of an actuator according to one embodiment of this application is shown.

[0035] One embodiment of this application provides an actuator, including a housing 10 and a motor 9 and a hollow planetary reduction gear structure disposed within the housing 10. The motor 9 includes a rotor 92, a stator 91, and an output shaft 93. The stator 91 is fixed to the inner wall of the housing 10. The rotor 92 can rotate under the drive of the stator 91. The output shaft 93 is used to drive the hollow planetary reduction gear structure to the rotor 92, so that the motor 9 can achieve deceleration output through the hollow planetary reduction gear structure.

[0036] Combination Figure 3 As shown, Figure 3 An exploded view of an actuator according to one embodiment of this application is shown. In some embodiments, [the following is a description of the actuator]. Figure 3 As shown in the example, motor 9 is specifically an external rotor motor. The rotor 92 is located on the periphery of stator 91 and can rotate around the central shaft G1 under the drive of stator 91, so as to drive the hollow planetary reduction structure connected to the output shaft 93 to achieve outward deceleration output.

[0037] In this embodiment of the application, the central axis G1 may be the central axis of the output shaft 93.

[0038] It is understood that in some other embodiments, the motor 9 can also be configured as an internal rotor motor, with the rotor 92 installed inside the stator 91 and able to rotate around the central axis G1 under the drive of the stator 91, which can also drive the hollow planetary reduction structure connected to the output shaft 93 to output to the outside.

[0039] See Figure 2As shown in this embodiment, the output shaft 93 is constructed as a hollow structure, with a wiring channel 931 inside the output shaft 93, which runs through the output shaft 93 along its axial direction. After the hollow planetary reduction gear structure is installed on the output shaft 93, the wiring channel 931 in the central area of ​​the output shaft 93 forms a through space, which can be used to accommodate flexible cables such as the power cable and encoder signal cable of the motor 9, thereby avoiding the layout chaos and motion interference caused by external cables in traditional structures.

[0040] Continue reading Figure 2 and Figure 3 As shown, the hollow planetary deceleration structure includes a first-stage planetary mechanism, a second-stage planetary mechanism, and a planet carrier 7. Figure 2 As shown in the example, the first-stage planetary mechanism, planet carrier 7, and second-stage planetary mechanism are arranged sequentially, with the first-stage planetary mechanism being closer to the stator 91 of the motor 9 than the second-stage planetary mechanism. The planet carrier 7 has a connecting hole 71 at the center of the shaft, through which the output shaft 93 of the motor 9 can pass and be fixed relative to the planet carrier 7.

[0041] In this embodiment, the output shaft 93 and the planetary carrier 7 can be relatively fixed by an interference fit. In other embodiments, the output shaft 93 and the planetary carrier 7 can also be fixed by a spline connection. It is understood that in other embodiments, the output shaft 93 and the planetary carrier 7 can also be relatively fixed by other means, and this application does not limit this.

[0042] See Figure 3 As shown, the first-stage planetary mechanism includes a first-stage gear ring 1 and multiple first-stage planetary gears 2 meshing with the first-stage gear ring 1. The outer rings of the first-stage planetary gears 2 can be fixed to the inner wall of the housing 10. The second-stage planetary mechanism includes a second-stage gear ring 3 and multiple second-stage planetary gears 4 meshing with the second-stage gear ring 3. Along the extension direction of the central axis G1, multiple through holes 72 are provided on the planet carrier 7, and the through holes 72 are spaced apart along the axial direction of the planet carrier 7.

[0043] In this embodiment, the through holes 72 are evenly distributed along the circumference of the planet carrier 7. The secondary planetary mechanism also includes multiple connecting pins 5. Along the extension direction of the central axis G1, the connecting pins 5 are correspondingly inserted into the through holes 72. The secondary planetary gear 4 is connected to the primary planetary gear 2 one-to-one by means of the connecting pins 5.

[0044] Among them, the planet carrier 7, the first-stage gear ring 1 and the second-stage gear ring 3 are all coaxially arranged with the central shaft G1 as the axis. The planet carrier 7 is coaxially fixed to the output shaft 93 of the motor 9. The connecting pin 5 passes through the planet carrier 7 and connects between the first-stage planetary gear 2 and the second-stage planetary gear 4.

[0045] In this embodiment, the primary gear ring 1 is fixed relative to the housing 10, and the secondary gear ring 3 is configured to rotate relative to the housing 10 around the central axis G1. When the actuator operates, power is transmitted from the output shaft 93 to the planet carrier 7 and then to the primary planetary gear 2. Simultaneously, since the primary gear ring 1 is fixed relative to the housing 10, the motion of the primary planetary gear 2 is a composite motion of rotation and revolution, thereby driving the secondary planetary gear 4 to perform a composite motion of rotation and revolution. Ultimately, the power is transmitted through the secondary planetary gear 4, driving the secondary gear ring 3 to output power externally.

[0046] Furthermore, in some embodiments, the hollow planetary reducer structure also includes a connector 8. A mounting groove 81 is provided on the end face of the secondary gear ring 3 facing away from the planet carrier 7. The connector 8 is accommodated within the mounting groove 81 and is drively connected to the planet carrier 7, and can rotate relative to the secondary gear ring 3 under the drive of the planet carrier 7. In this embodiment, the connector 8 is fixed to the planet carrier 7 by means of a pin and can rotate synchronously with the rotation of the planet carrier 7.

[0047] See Figure 2 and Figure 3 As shown, in some embodiments, in order to restrict the overall axial position of the hollow planetary reduction structure, the hollow planetary reduction structure further includes a positioning bearing 6, which is disposed between the outer ring of the secondary gear ring 3 and the inner wall of the housing 10, so that the secondary gear ring 3 can be rotatably installed in the housing 10 to achieve the reduction output of the motor 9 power.

[0048] The positioning bearing 6 serves both radial and axial support and positioning functions for the secondary gear ring 3. This application integrates the independent gear ring support structure of a traditional planetary mechanism with the inner ring of the bearing, using the positioning bearing 6 to replace the axial positioning component of the secondary gear ring 3, thus reducing the axial dimension of the single-stage planetary mechanism. The two-stage planetary structure, through the coaxial integration of the inner ring of the positioning bearing 6 and the secondary gear ring 3, results in a small increase in the overall axial dimension of the actuator. The integrated design of the secondary gear ring 3 support structure and the inner ring of the positioning bearing 6 effectively reduces the axial dimension of the reducer.

[0049] Furthermore, a positioning groove 82 is provided on the side of the secondary gear ring 3 near the planetary carrier 7, and the positioning groove 82 is arranged circumferentially along the secondary gear ring 3. The inner ring of the positioning bearing 6 abuts against the bottom of the positioning groove 82, and the end face of the positioning bearing 6 abuts against the groove wall of the positioning groove 82, so as to achieve dual positioning of the secondary gear ring 3 in both axial and radial directions, and avoid abnormal axial movement of the primary and secondary planetary mechanisms during operation.

[0050] Continue reading Figure 2As shown, in some other embodiments, the actuator also includes a first support bearing 11 disposed within the housing 10. The first support bearing 11 is disposed between the outer ring of the planetary carrier 7 and the inner wall of the housing 10 to provide radial support for the planetary carrier 7, thereby reducing the vibration of the planetary carrier 7 during operation and ensuring the stability of the planetary carrier 7 during operation.

[0051] The actuator also includes a second support bearing 12 disposed within the housing 10. Along the extension direction of the central shaft G1, the second support bearing 12 is arranged opposite to the first support bearing 11 and opposite to the positioning bearing 6. It is located between the side wall of the output shaft 93 and the inner wall of the housing 10 to achieve radial support for the output shaft 93, thereby preventing abnormal vibration of the output shaft 93 during operation.

[0052] In other embodiments, this application also provides a robot (not shown) including an actuator as shown in any of the above embodiments, a body (not shown), and legs (not shown). The actuator connects the legs to the body, acting as a joint between the legs and the body, allowing the legs to be pivotally connected to the body.

[0053] In this application embodiment, the robot includes, but is not limited to, semi-mobile robots (e.g., robotic arms, linear coordinate robots, cylindrical coordinate robots, articulated robots, etc.) and mobile robots (e.g., wheeled mobile robots, walking mobile robots, crawling robots, etc.).

[0054] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A hollow planetary reduction structure, characterized by, The hollow planetary deceleration structure includes: case; A primary planetary mechanism includes a primary gear ring and a plurality of primary planetary gears meshing with the primary gear ring, the primary gear ring being fixed to the housing; A secondary planetary mechanism includes a secondary gear ring and a plurality of secondary planetary gears meshing with the secondary gear ring, the secondary gear ring being rotatably mounted on the housing; A planetary carrier, disposed between the first-stage planetary mechanism and the second-stage planetary mechanism, is coaxially fixed to the output shaft of the motor; and... A connecting pin is inserted through the planet carrier, and the secondary planetary gears are fixed to the primary planetary gears one by one by means of the connecting pin.

2. The hollow planetary deceleration structure according to claim 1, characterized in that, The hollow planetary reduction structure also includes a positioning bearing, which is located between the secondary gear ring and the housing, and is used to rotatably mount the secondary gear ring onto the housing.

3. The hollow planetary deceleration structure according to claim 1, characterized in that, The planetary carrier has a connecting hole at its center, which is used for the output shaft of the motor to pass through.

4. The hollow planetary deceleration structure according to claim 1, characterized in that, The planetary carrier includes multiple through holes, which are spaced apart circumferentially along the planetary carrier, and the connecting pins are inserted through the through holes one by one.

5. The hollow planetary deceleration structure according to any one of claims 1-4, characterized in that, The hollow planetary reduction structure also includes a connector. The second-stage gear ring has a mounting groove on its end face away from the planet carrier. The connector is accommodated in the mounting groove and is connected to the planet carrier in a driving manner. It is also rotatable relative to the second-stage gear ring.

6. An actuator, characterized in that, The actuator includes: An electric motor includes a stator, a rotor, and an output shaft, wherein the output shaft is fixed to the rotor, and the rotor is capable of driving the output shaft to rotate under the drive of the stator; and The hollow planetary reduction gear structure as described in any one of claims 1-5 is connected to the output shaft via a transmission.

7. The actuator according to claim 6, characterized in that, The output shaft has a wiring channel that extends through the output shaft along its axial direction.

8. The actuator according to claim 6, characterized in that, It also includes a first support bearing disposed within the housing, the first support bearing being disposed between the planetary carrier and the housing.

9. The actuator according to claim 8, characterized in that, It also includes a second support bearing disposed within the housing. Along the axial direction of the output shaft, the second support bearing is arranged opposite to the first support bearing, and the second support bearing is disposed between the output shaft and the housing.

10. A robot, characterized in that, Includes an actuator as described in any one of claims 6-9, the actuator serving as a joint of the robot.

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