A collimating driven joint actuator, a robot joint and a robot

Abstract

The application discloses a kind of collimating drive joint actuators, robot joints and robots in the technical field of robot joint actuators, including shell, driving device and planetary reducer, the planetary reducer includes input wheel, planetary gear train, output wheel and mounting bracket, the planetary gear train includes sun gear, planet wheel, planet carrier, inner ring gear and planet shaft;The sun gear is continuous full elliptical tooth profile gear, the planet wheel is double planet wheel, including first planet wheel and second planet wheel, the first planet wheel is engaged with the sun gear, the second planet wheel is engaged with the inner ring gear.The collimating drive joint actuator provided by the application has the characteristics of high torque density, high bearing capacity and torque transparency.

Description

Technical Field

[0001] This invention relates to the field of robot joint actuator technology, specifically to a quasi-direct drive joint actuator, a robot joint, and a robot. Background Technology

[0002] Currently, the integrated joint actuators commonly used in robots highly integrate an internal rotor motor, a high-ratio precision reducer, sensors, drivers, and torque sensors into one unit. Power is transmitted through a high-ratio reducer, sacrificing dynamic response for high torque density output. In contrast, collimated drive actuators achieve more direct power transmission by integrating a high-torque-density motor with a low-ratio involute gear planetary reducer, thereby significantly improving dynamic response speed and force control bandwidth. This results in near-direct force sensing accuracy and motion transparency, making them particularly suitable for cutting-edge applications such as bionic robots and collaborative robots that require high agility, precise and compliant force control, safe human-machine interaction, and high-bandwidth dynamic response. However, involute gears are limited by the minimum number of undercut teeth, resulting in a smaller gear module and lower strength within a limited external dimension. This makes them unsuitable for applications involving overload and impact, necessitating the urgent need for new transmission alternatives to address load-bearing capacity issues. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a quasi-direct drive joint actuator, robot joint and robot, which can better meet the requirements of high dynamic response and overload and impact conditions, and is suitable for robot joint scenarios with high dynamic start and stop.

[0004] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0005] In a first aspect, the present invention provides a quasi-direct drive joint actuator, comprising: a housing, a drive unit, and a planetary reducer, wherein the drive unit and the planetary reducer are both installed inside the housing;

[0006] The planetary reducer includes an input gear, a planetary gear train, an output gear, and a mounting bracket. The planetary gear train includes a sun gear, planet gears, a planet carrier, an internal gear ring, and a planet shaft. The input gear is connected to the output end of the drive unit and is fixedly connected to the sun gear. The input gear, sun gear, planet carrier, internal gear ring, and output gear are all coaxial. The planet gears are mounted on the planet shaft via bearings. The planet shaft is fixedly connected to the planet carrier, which is fixedly connected to the output gear. The internal gear ring is fixedly connected to the mounting bracket, which is fixedly connected inside the housing. The planet gears mesh conjugately with the sun gear and the internal gear ring. The drive unit drives the sun gear to rotate, thereby causing the planet gears to rotate on their own axes, revolve around the internal gear ring, drive the planet carrier to rotate, and ultimately drive the output gear to rotate.

[0007] The sun gear is a continuous elliptical tooth profile gear, and the planet gear is a double planet gear, including a first planet gear and a second planet gear. The first planet gear and the second planet gear are arranged along the axial direction of the planet shaft and are both mounted on the planet shaft by bearings. The first planet gear meshes conjugately with the sun gear, and the second planet gear meshes conjugately with the internal gear ring.

[0008] Furthermore, the equation for the fully elliptical end face tooth profile of the sun gear is:

[0009]

[0010] in, Let be the coordinates of any point on the tooth profile; The minor axis radius of the sun gear; The radius of the major axis of the sun gear; The angle parameter of the sun gear tooth profile equation has a range of values. , which represents a tooth profile period within a defined domain.

[0011] Furthermore, the end face tooth profile equation of the double planetary gear is:

[0012]

[0013] in, To generate the first The ellipse of the end face tooth profile equation of the planetary gear rotates about the center by an angle. For the first The angle of rotation of the planetary gear around the center; For the first The angle parameters of the end face tooth profile equation of the planetary gear have a range of values. , To generate the first The center of the ellipse in the end face tooth profile equation of the planetary gear is related to the first... Distance between the centers of the planetary gears For the first The generation of planetary wheels The ratio of the rotation angles of the ellipse in the end face tooth profile equation of the planetary gear. , To generate the first The major and minor axis radii of the ellipse in the equation of the end face tooth profile of the planetary gear; ,when At that time, the first The planetary wheel represents the first planetary wheel, when At that time, the first The planetary wheel refers to the second planetary wheel.

[0014] Furthermore, the tooth profile equation of the internal gear ring is:

[0015]

[0016] in, The angle of rotation of the second planetary gear around the center; The angle of rotation of the internal gear ring around its center; It is the ratio of the rotation angles of the second planetary gear and the internal gear ring when they rotate around a fixed axis.

[0017] Furthermore, the drive device includes a rotor and a stator, the stator being disposed within the housing, the rotor being coaxially arranged with the stator, and the rotor being connected to the axis of the sun gear.

[0018] Furthermore, the rotor is sleeved outside the stator and planetary reducer, and the stator and planetary reducer are arranged along the axial direction of the rotor.

[0019] Furthermore, the housing includes a front cover, a rear cover, and a drive unit protective cover. The planetary reducer is installed between the front cover and the rear cover. The front cover and the rear cover are connected by threads. The drive unit protective cover is installed on the side of the front cover away from the rear cover.

[0020] In a second aspect, the present invention provides a robot joint, including the collimated joint actuator.

[0021] Thirdly, the present invention provides a robot including the aforementioned robot joint.

[0022] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0023] The quasi-direct drive joint actuator provided by this invention includes a housing, a drive unit, and a planetary reducer. The planetary reducer includes an input gear, a planetary gear train, an output gear, and a mounting bracket. The planetary gear train includes a sun gear, planet gears, a planet carrier, an internal gear ring, and planet shafts. The sun gear has a continuous fully elliptical tooth profile. The conjugate meshing tooth profile of the sun gear and a new tooth profile that meshes conjugately with the conjugate meshing tooth profile of the sun gear constitute a two-stage conjugate gear pair. Compared with an involute gear pair, it has fewer teeth and a larger module, which can achieve a larger transmission ratio in a smaller space. The gear pairs are all conjugate meshing and have a small induced curvature, resulting in high gear contact and bending strength. It can achieve continuous constant transmission ratio transmission, reduce sliding friction loss, and improve transmission efficiency. This gives the joint actuator high torque density, high load-bearing capacity, and torque transparency, which can better meet the requirements of high dynamic response, overload, and impact conditions, and is suitable for robot joint scenarios with high dynamic frequency start and stop. This invention solves the problems of insufficient torque density of traditional direct-drive joint actuators, excessive axial dimension of planetary reducers, low overload capacity, and poor impact resistance. Considering the structural features and design difficulty, the planetary gear system provided by this invention has a good balance in terms of manufacturing difficulty and cost. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the quasi-direct drive joint actuator provided in an embodiment of the present invention;

[0025] Figure 2 for Figure 1 A structural diagram from another perspective;

[0026] Figure 3 This is a cross-sectional view of a quasi-direct drive joint actuator provided in an embodiment of the present invention;

[0027] Figure 4 An exploded view of a quasi-direct drive joint actuator provided in an embodiment of the present invention;

[0028] Figure 5 An exploded view of a planetary reducer provided in an embodiment of the present invention;

[0029] Figure 6 An exploded view of a planetary gear train provided in an embodiment of the present invention;

[0030] Figure 7 An exploded view of the sun gear and planet carrier provided in an embodiment of the present invention;

[0031] Figure 8 A schematic diagram of the tooth profile of the first planetary gear and the sun gear in conjugate meshing, provided for an embodiment of the present invention;

[0032] Figure 9 This is a schematic diagram of the tooth profile of the second planetary gear and the internal gear ring in conjugate meshing, provided for an embodiment of the present invention.

[0033] In the diagram: 100, housing; 200, drive unit; 300, planetary reducer; 400, motor drive board; 110, drive unit protective cover; 120, front cover; 130, rear cover; 210, rotor; 220, stator; 310, output gear; 320, planetary gear train; 330, input gear; 340, mounting bracket; 321, sun gear; 322, planetary gears; 323, internal gear ring; 324, planet carrier; 325, planetary shaft; 3221, first planetary gear; 3222, second planetary gear. Detailed Implementation

[0034] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Example 1

[0036] This embodiment provides a quasi-direct drive joint actuator, including: a housing 100, a drive device 200 and a planetary reducer 300, wherein the drive device 200 and the planetary reducer 300 are both installed inside the housing 100;

[0037] like Figure 5 As shown, the planetary reducer 300 includes an input gear 330, a planetary gear train 320, an output gear 310, and a mounting bracket 340, as... Figure 3 , Figure 6 As shown, the planetary gear train 320 includes a sun gear 321, planet gears 322, a planet carrier 324, an internal gear ring 323, and a planet shaft 325. The input gear 330 is connected to the output end of the drive device 200 and is fixedly connected to the sun gear 321. The input gear 330, sun gear 321, planet carrier 324, internal gear ring 323, and output gear 310 are all coaxial. The planet gears 322 are mounted on the planet shaft 325 via bearings, and the planet shaft 325 is fixedly connected to the planet carrier 324. The planetary carrier 324 is fixedly connected to the output gear 310. The internal gear ring 323 is fixedly connected to the mounting bracket 340, which is fixedly connected inside the housing 100. The planetary gear 322 is conjugately meshed with the sun gear 321 and the internal gear ring 323. The drive device 200 is used to drive the sun gear 321 to rotate at high speed, thereby driving the planetary gear 322 to rotate on its own axis, causing the planetary gear 322 to revolve around the internal gear ring 323, driving the planetary carrier 324 to rotate, and then driving the output gear 310 to rotate at low speed and output torque.

[0038] In this embodiment, the sun gear 321 is a continuously elliptical tooth profile gear, and the planet gear 322 is a double planet gear 322, including a first planet gear 3221 and a second planet gear 3222. The first planet gear 3221 and the second planet gear 3222 are arranged along the axial direction of the planetary shaft 325 and are both mounted on the planetary shaft 325 by bearings. Figure 8 As shown, the first planetary gear 3221 and the sun gear 321 are conjugate meshed, as... Figure 9 As shown, the second planetary gear 3222 engages conjugately with the internal gear ring 323.

[0039] The equation for the continuous fully elliptical end face tooth profile of the sun gear 321 is:

[0040]

[0041] in, Let be the coordinates of any point on the tooth profile; The minor axis radius of the sun gear; The radius of the major axis of the sun gear; The angle parameter has a range of values. , which represents a tooth profile period within a defined domain.

[0042] The end face tooth profile equation of the double planetary gear 322 is:

[0043]

[0044] in, To generate the first The ellipse of the end face tooth profile equation of the planetary gear rotates about the center by an angle. For the first The angle of rotation of the planetary gear around the center; For the first The angle parameters of the end face tooth profile equation of the planetary gear have a range of values. , To generate the first The center of the ellipse in the end face tooth profile equation of the planetary gear is related to the first... Distance between the centers of the planetary gears For the first The generation of planetary wheels The ratio of the rotation angles of the ellipse in the end face tooth profile equation of the planetary gear, when Generate an elliptic virtual ellipse for the end face tooth profile equation of the second planetary gear. , To generate the first The major and minor axis radii of the ellipse in the equation of the end face tooth profile of the planetary gear; ,when At that time, the first The planetary wheel represents the first planetary wheel, when At that time, the first The planetary wheel refers to the second planetary wheel.

[0045] The tooth profile equation of the internal gear ring 323 is:

[0046]

[0047] in, The angle of rotation of the second planetary gear around the center; The angle of rotation of the internal gear ring around its center; It is the ratio of the rotation angles of the second planetary gear and the internal gear ring when they rotate around a fixed axis.

[0048] The formula for calculating the total transmission ratio of planetary gear 322 is:

[0049]

[0050] in, The transmission ratio is... The number of teeth on the sun gear 321. This refers to the number of teeth on the first planetary gear 3221 in planetary gear 322. This refers to the number of teeth on the second planetary gear 3222 in planetary gear 322. This represents the number of teeth on the internal gear ring 323.

[0051] In this embodiment, by using formulas and combining the dimensions of the drive device 200 and the housing 100, and under the conditions of satisfying the transmission ratio of the first planetary gear 3221 and the second planetary gear 3222 and the assembly requirements of each component, the center distance of the first planetary gear 3221 is determined. Set to 7, gear ratio Set to 4, minor axis radius of sun gear 321 Set to 2, the major axis radius of sun gear 321 Set to 3, the number of teeth on the sun gear is 321. Set to 2, the number of teeth of the first planetary gear 3221 Setting it to 8 allows us to derive the end face tooth profile equation of the sun gear 321 and the end face tooth profile equation of the first planet gear 3221 in the planet gear 322 in this embodiment.

[0052] Similarly, the center distance of the second planetary gear 3222 Set to 5, transmission ratio Set to 2.5, minor axis radius of sun gear 321 The major axis radius of the sun gear 321 is 4. Set to 6, the number of teeth on the second planetary gear. Set to 4, number of teeth on internal gear ring 323 Setting it to 10 allows us to derive the end face tooth profile equations of the second planetary gear 3222 and the internal gear ring 323 that meshes with it, and also allows us to calculate the transmission ratio of the planetary gear 322. It is 11.

[0053] like Figure 4 As shown, in this embodiment, the drive device 200 includes a rotor 210 and a stator 220. The stator 220 is disposed inside the housing 100. The rotor 210 is coaxially arranged with the stator 220, and the rotor 210 is connected to the axis of the sun gear 321.

[0054] The rotor 210 is sleeved outside the stator 220 and the planetary reducer 300. The stator 220 and the planetary reducer 300 are arranged along the axial direction of the rotor 210. In the drive device 200, when the stator 220 is energized, it generates a rotating magnetic field. Under the action of the rotating magnetic field, the rotor 210 will rotate, which in turn will drive the input wheel 330 to rotate, and then drive the sun gear 321 to rotate. In this embodiment, the rotor 210 is sleeved outside the stator 220, and the planetary reducer 300 is also located inside the rotor 210. This reduces the axial dimension of the collimation joint, making the overall structure more compact.

[0055] like Figure 1 As shown, the drive device 200 also includes a motor drive board 400, which converts logic control signals into current and voltage waveforms required by the motor, and realizes the motor's start-up, shutdown, direction adjustment, speed regulation, and precise positioning by adjusting voltage, frequency, or pulse parameters. The motor drive board adjusts the power supply parameters of the stator 220, thereby controlling the rotational speed of the rotor 210.

[0056] like Figure 2 As shown, the housing 100 includes a front cover 120, a rear cover 130, and a drive unit protective cover 110. The planetary reducer 300 is installed between the front cover 120 and the rear cover 130, which are connected by threads. The drive unit protective cover 110 is installed on the side of the front cover 120 away from the rear cover 130. In this embodiment, the front cover 120 and the rear cover 130 can be easily molded and assembled separately. After assembling the drive unit 200 and the planetary reducer 300 inside the housing 100, the collimating drive joint becomes an independent module. The front cover 120 and the rear cover 130 can be connected by fasteners, making assembly easy.

[0057] like Figure 5 , Figure 6 and Figure 7 As shown, the sun gear 321 includes a connecting shaft portion and a connecting shaft gear portion. The first end of the connecting shaft is coaxially fixed to the motor shaft, while the second end of the connecting shaft is supported on the planetary carrier 324 via bearings. The motor shaft is supported on the housing 100 via bearings. Inserting the second end of the connecting shaft into the planetary carrier and supporting it with bearings makes the planetary reducer 300 compact. The motor shaft and sun gear 321 are coaxially fixed, and with the support of the sun gear 321 and bearings, the motor shaft remains coaxial with the rotor 210, facilitating stable rotation of the motor shaft and sun gear 321, reducing resistance during rotation, and improving reliability.

[0058] Example 2

[0059] This embodiment provides a robot joint, including the quasi-direct drive joint actuator described in Embodiment 1.

[0060] Example 3

[0061] This embodiment provides a robot, including the robot joint described in Embodiment 2.

[0062] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to explain the relative positional relationship and movement between components in a specific posture. If the specific posture changes, the directional indication will also change accordingly. They are used only for the convenience of describing the invention and for 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. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0063] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0064] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A prismatic driven joint actuator, characterized by, include: The housing, drive unit, and planetary reducer are all housed within the housing. The planetary reducer includes an input gear, a planetary gear train, an output gear, and a mounting bracket. The planetary gear train includes a sun gear, planet gears, a planet carrier, an internal gear ring, and a planet shaft. The input gear is connected to the output end of the drive unit and is fixedly connected to the sun gear. The input gear, sun gear, planet carrier, internal gear ring, and output gear are all coaxial. The planet gears are mounted on the planet shaft via bearings. The planet shaft is fixedly connected to the planet carrier, which is fixedly connected to the output gear. The internal gear ring is fixedly connected to the mounting bracket, which is fixedly connected inside the housing. The planet gears mesh conjugately with the sun gear and the internal gear ring. The drive unit drives the sun gear to rotate, thereby causing the planet gears to rotate on their own axes, revolve around the internal gear ring, drive the planet carrier to rotate, and ultimately drive the output gear to rotate. The sun gear is a continuous elliptical tooth profile gear, and the planet gear is a double planet gear, including a first planet gear and a second planet gear. The first planet gear and the second planet gear are arranged along the axial direction of the planet shaft and are both mounted on the planet shaft by bearings. The first planet gear meshes conjugately with the sun gear, and the second planet gear meshes conjugately with the internal gear ring. The equation for the fully elliptical end face tooth profile of the sun gear is: ； wherein, is the coordinate of any point on the tooth profile; is the minor axis radius of the sun gear; is the major axis radius of the sun gear; is the angle parameter of the tooth profile equation of the sun gear, and the value range thereof is represents a tooth profile period within a definition domain; The end face tooth profile equation of the double planetary gear is: ； wherein, is the rotation angle of the ellipse of the face gear profile equation of the first planetary gear around the center; is the rotation angle of the ellipse of the face gear profile equation of the first planetary gear around the center; is the rotation angle of the ellipse of the face gear profile equation of the first planetary gear, which is in the range of , is the center distance of the ellipse of the face gear profile equation of the first planetary gear and the center of the first planetary gear; is the rotation angle ratio of the ellipse of the face gear profile equation of the first planetary gear and the ellipse of the face gear profile equation of the first planetary gear; , is the major axis and minor axis radius of the ellipse of the face gear profile equation of the first planetary gear; when , the first planetary gear represents the first planetary gear, and when , the first planetary gear represents the second planetary gear.

2. The colinear prismatic actuator of claim 1, wherein: The tooth profile equation of the internal gear ring is: ； wherein, is the angle of rotation of the second planetary gear about the center; is the angle of rotation of the ring gear about the center; is the ratio of the angles of rotation of the second planetary gear and the ring gear when rotating about the axis.

3. The colinear prismatic actuator of claim 1, wherein: The drive device includes a rotor and a stator. The stator is disposed inside the housing. The rotor is coaxially arranged with the stator and connected to the axis of the sun gear.

4. The colinear prismatic actuator of claim 3, wherein: The rotor is sleeved outside the stator and planetary reducer, which are arranged along the axial direction of the rotor.

5. The colinear prismatic actuator of claim 1, wherein: The housing includes a front cover, a rear cover, and a drive unit protective cover. The planetary reducer is installed between the front cover and the rear cover. The front cover and the rear cover are connected by threads. The drive unit protective cover is installed on the side of the front cover away from the rear cover.

6. A robot joint, characterized by Includes the collimated joint actuator as described in any one of claims 1-5.

7. A robot, characterized in that Including the robot joint as described in claim 6.

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