Collimating direct-drive joint actuator, robot joint and robot

Abstract

The invention discloses a collimated direct-drive joint actuator, a robot joint and a robot in the technical field of robot joint actuators, and the collimated direct-drive joint actuator comprises a shell, a driving device and a planetary reducer, the planetary reducer comprises an input wheel, a planetary gear train, an output wheel and a mounting bracket, the planetary gear train comprises a sun gear, a planet gear, a planet carrier, an inner gear ring and a planet shaft; the sun gear is a continuous full-oval tooth profile gear, the planet gears are duplex planet gears and comprise the first planet gear and the second planet gear, the first planet gear is meshed with the sun gear in a conjugate mode, and the second planet gear is meshed with the inner gear ring in a conjugate mode. The collimation direct-drive joint actuator has the advantages of being high in torque density, high in bearing capacity and high in torque transparency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of robot joint actuators, in particular to a collinear drive joint actuator, a robot joint and a robot. BACKGROUND

[0002] The current integrated joint actuator commonly used in robots highly integrates an inner rotor motor, a high transmission ratio precision reducer, a sensor, a driver and a torque sensor into one body. Power is transmitted through a high-speed ratio reducer, sacrificing dynamic response for high torque density output. The collinear drive actuator realizes more direct power transmission by integrating a high torque density motor and a low reduction ratio involute gear planetary reducer, thereby significantly improving dynamic response speed and force control bandwidth, bringing nearly direct force sensing accuracy and motion transparency, and is particularly suitable for cutting-edge application scenarios such as bionic robots, collaborative robots and the like that require high agility, fine compliant force control, safe human-robot interaction and high bandwidth dynamic response. However, the involute gear is limited by the minimum root tooth number, resulting in a small gear modulus and low strength in a limited size, which is not suitable for overload and impact applications, and a new transmission solution is urgently needed to solve the bearing capacity problem. SUMMARY

[0003] The present application aims to overcome the deficiencies in the prior art and provide a collinear drive joint actuator, a robot joint and a robot that can better meet the requirements of high dynamic response and overload and impact working conditions, and adapt to high dynamic start-stop robot joint scenarios.

[0004] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0005] In a first aspect, the present application provides a collinear drive joint actuator, comprising a housing, a driving device and a planetary reducer, wherein the driving device and the planetary reducer are both mounted in the housing;

[0006] The planetary reducer comprises an input wheel, a planetary gear train, an output wheel and a mounting bracket, wherein the planetary gear train comprises a sun gear, a planet gear, a planet carrier, an inner ring gear and a planet shaft; the input wheel is in transmission connection with the output end of the driving device and is fixedly connected with the sun gear, the input wheel, the sun gear, the planet carrier, the inner ring gear and the output wheel are coaxial; the planet gear is mounted on the planet shaft through a bearing, the planet shaft is fixedly connected with the planet carrier, the planet carrier is fixedly connected with the output wheel, the inner ring gear is fixedly connected with the mounting bracket, the mounting bracket is fixedly connected inside the housing, and the planet gear is in conjugate engagement with the sun gear and the inner ring gear; the driving device is used to drive the sun gear to rotate, thereby driving the planet gear to rotate around the sun gear, driving the planet carrier to rotate, and further driving the output wheel to rotate;

[0007] The sun gear is a continuous full 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 installed on the planet shaft through bearings. The first planet gear is conjugately meshed with the sun gear, and the second planet gear is conjugately meshed with the inner ring gear.

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

[0009]

[0010] in, 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 sun gear tooth profile equation, and its value range is , represents a tooth profile period within a domain of definition.

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

[0012]

[0013] in, To generate the The angle of rotation of the ellipse of the planetary gear end face tooth profile equation around the center; For the The angle of rotation of the planetary gear around the center; For the The angle parameter of the planetary gear end face tooth profile equation has a value range of , To generate the The center of the ellipse of the planetary gear end face tooth profile equation is The center distance of the planetary gear, For the The generation of planetary gears The rotation angle ratio of the ellipse of the planetary gear end face tooth profile equation, 、 To generate the The major and minor axis radii of the ellipse of the planetary gear end face tooth profile equation; ,when When, Planetary gear represents the first planetary gear, when When, The planet gear represents the second planet gear.

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

[0015]

[0016] wherein, is the rotation angle of the second planet wheel around the center; is the rotation angle of the inner ring around the center; is the rotation angle ratio of the second planet wheel and the inner ring when the rotation is fixed.

[0017] Further, the driving device comprises a rotor and a stator, the stator is arranged in the shell, the rotor is coaxially arranged with the stator, and the rotor is connected with the shaft center of the sun gear.

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

[0019] Further, the shell comprises a front cover, a rear cover and a driving device protection cover, the planetary reducer is installed between the front cover and the rear cover, the front cover and the rear cover are connected through threads, and the driving device protection cover is installed on the side of the front cover away from the rear cover.

[0020] In a second aspect, the present application provides a robot joint comprising the collinear drive joint actuator.

[0021] In a third aspect, the present application provides a robot comprising the robot joint.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] The collinear drive joint actuator provided by the present application comprises a shell, a driving device and a planetary reducer, the planetary reducer comprises an input wheel, a planetary gear train, an output wheel and a mounting bracket, the planetary gear train comprises a sun gear, a planet wheel, a planet carrier, an inner ring and a planet shaft, the sun gear is a continuous full-elliptical tooth profile, a tooth profile that is conjugate with the sun gear and a new tooth profile that is conjugate with the tooth profile that is conjugate with the sun gear, constitute a two-stage conjugate gear pair, compared with a involute gear pair, the gear pair has less teeth and larger modulus, and a larger transmission ratio can be achieved in a smaller space, the gear pair is conjugate and has small induced curvature, the gear contact and bending strength are high, continuous constant transmission ratio transmission can be achieved, sliding friction loss is reduced, transmission efficiency is improved, the joint actuator has high torque density, high bearing capacity and torque transparency, can better meet high dynamic response and overload and impact working conditions, and is suitable for robot joint scenes with high dynamic frequency start-stop. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Structure diagram of the collinear driven joint actuator provided by the embodiment of the present application;

[0025] Figure 2 Structure diagram of the collinear driven joint actuator provided by the embodiment of the present application; Figure 1 Structure diagram of the collinear driven joint actuator provided by the embodiment of the present application;

[0026] Figure 3 Structure diagram of the collinear driven joint actuator provided by the embodiment of the present application;

[0027] Figure 4 Structure diagram of the collinear driven joint actuator provided by the embodiment of the present application;

[0028] Figure 5 Structure diagram of the collinear driven joint actuator provided by the embodiment of the present application;

[0029] Figure 6 Structure diagram of the collinear driven joint actuator provided by the embodiment of the present application;

[0030] Figure 7 Structure diagram of the collinear driven joint actuator provided by the embodiment of the present application;

[0031] Figure 8 Structure diagram of the collinear driven joint actuator provided by the embodiment of the present application;

[0032] Figure 9 Structure diagram of the collinear driven joint actuator provided by the embodiment of the present application.

[0033] In the figure: 100, housing; 200, driving device; 300, planetary reducer; 400, motor driving board; 110, driving device protection cover; 120, front cover; 130, rear cover; 210, rotor; 220, stator; 310, output wheel; 320, planetary gear train; 330, input wheel; 340, mounting bracket; 321, sun gear; 322, planetary gear; 323, inner gear ring; 324, planet carrier; 325, planet shaft; 3221, first planetary gear; 3222, second planetary gear. DETAILED DESCRIPTION

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0035] Embodiment 1

[0036] The embodiment provides a collimating driven joint actuator, which comprises a shell 100, a driving device 200 and a planetary reducer 300, wherein the driving device 200 and the planetary reducer 300 are both mounted in the shell 100.

[0037] As shown in Figure 5 , the planetary reducer 300 comprises an input wheel 330, a planetary gear train 320, an output wheel 310 and a mounting bracket 340, as shown in Figure 3 、 Figure 6 , the planetary gear train 320 comprises a sun gear 321, a planet gear 322, a planet carrier 324, an inner ring gear 323 and a planet shaft 325; wherein the input wheel 330 is in transmission connection with an output end of the driving device 200 and is fixedly connected with the sun gear 321, the input wheel 330, the sun gear 321, the planet carrier 324, the inner ring gear 323 and the output wheel 310 are all coaxial, the planet gear 322 is mounted on the planet shaft 325 through a bearing, the planet shaft 325 is fixedly connected with the planet carrier 324, the planet carrier 324 is fixedly connected with the output wheel 310, the inner ring gear 323 is fixedly connected with the mounting bracket 340, the mounting bracket 340 is fixedly connected inside the shell 100, the planet gear 322 is in conjugate engagement with the sun gear 321 and the inner ring gear 323; the driving device 200 is used for driving the sun gear 321 to rotate at a high speed, so as to drive the planet gear 322 to rotate around the sun gear 321, drive the planet carrier 324 to rotate, and then drive the output wheel 310 to rotate at a low speed and output a torque;

[0038] In the embodiment, the sun gear 321 is a continuous full-elliptical tooth profile gear, the planet gear 322 is a double planet gear 322, comprising 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 planet shaft 325 and are both mounted on the planet shaft 325 through a bearing, as shown in Figure 8 , the first planet gear 3221 is in conjugate engagement with the sun gear 321, as shown in Figure 9 , the second planet gear 3222 is in conjugate engagement with the inner ring gear 323.

[0039] The continuous full-elliptical end face tooth profile equation of the sun gear 321 is as follows:

[0040]

[0041] wherein, is the coordinate of an arbitrary point on the tooth profile; is the minor axis radius of the sun gear; is the major axis radius of the sun gear; is an angle parameter, and the value range of the angle parameter is , represents a tooth profile period within a domain of definition.

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

[0043]

[0044] in, To generate the The angle of rotation of the ellipse of the planetary gear end face tooth profile equation around the center; For the The angle of rotation of the planetary gear around the center; For the The angle parameter of the planetary gear end face tooth profile equation has a value range of , To generate the The center of the ellipse of the planetary gear end face tooth profile equation is The center distance of the planetary gear, For the The generation of planetary gears The rotation angle ratio of the ellipse of the planetary gear end face tooth profile equation is , generate the elliptical dimension virtual ellipse of the end face tooth profile equation of the second planetary gear, 、 To generate the The major and minor axis radii of the ellipse of the planetary gear end face tooth profile equation; ,when When, Planetary gear represents the first planetary gear, when When, The planet gear represents the second planet gear.

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

[0046]

[0047] in, is the rotation angle of the second planetary gear around the center; is the rotation angle of the inner gear ring around the center; It is the rotation angle ratio of the second planetary gear and the inner gear ring when they rotate about the fixed axis.

[0048] The total transmission ratio of the planetary gear 322 is calculated as follows:

[0049]

[0050] in, is the transmission ratio, is the number of teeth of the sun gear 321, the number of teeth of the first planetary gear 3221 in the planetary gear 322, the number of teeth of the second planetary gear 3222 in the planetary gear 322, the number of teeth of the inner ring gear 323.

[0051] In the present embodiment, by the formula and in combination with the size of the driving device 200 and the housing 100, the center distance of the first planetary gear 3221 is set to 7, the transmission ratio set to 4, the minor axis radius of the sun gear 321 set to 2, the major axis radius of the sun gear 321 set to 3, the number of teeth of the sun gear 321 set to 2, the number of teeth of the first planetary gear 3221 set to 8, the end surface tooth profile equation of the sun gear 321 and the end surface tooth profile equation of the first planetary gear 3221 in the planetary gear 322 in the present embodiment can be obtained.

[0052] Similarly, the center distance of the second planetary gear 3222 is set to 5, the transmission ratio set to 2.5, the minor axis radius of the sun gear 321 set to 4, the major axis radius of the sun gear 321 set to 6, the number of teeth of the second planetary gear set to 4, the number of teeth of the inner ring gear 323 set to 10, the end surface tooth profile equation of the corresponding second planetary gear 3222 and the end surface tooth profile equation of the inner ring gear 323 which is in conjugate engagement with the second planetary gear 3222 can be obtained, and the transmission ratio of the planetary gear 322 is 11.

[0053] As Figure 4 shown in the present embodiment, the driving device 200 includes a rotor 210 and a stator 220, the stator 220 is arranged in the housing 100, the rotor 210 and the stator 220 are coaxially arranged, and the rotor 210 is connected with the axis of the sun gear 321.

[0054] The rotor 210 is sleeved outside the stator 220 and the planetary reducer 300 arranged in the axial direction of the rotor 210. When the stator 220 is powered, a rotating magnetic field is generated, and under the action of the rotating magnetic field, the rotor 210 rotates, thereby driving the input wheel 330 to rotate, and further driving 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 arranged inside the rotor 210, so that the axial size of the collinear drive joint can be reduced, and the overall structure is compact.

[0055] As shown in Figure 1 , the driving device 200 further comprises a motor drive board 400 for converting a logic control signal into a current and voltage waveform required by the motor, and through adjusting the voltage, frequency or pulse parameters, the start-stop, steering, speed regulation and accurate positioning of the motor are realized. The motor drive board adjusts the power supply parameters of the stator 220, thereby controlling the rotating speed of the rotor 210.

[0056] As shown in Figure 2 , the housing 100 comprises a front cover 120, a rear cover 130 and a driving device protection cover 110, the planetary reducer 300 is installed between the front cover 120 and the rear cover 130, the front cover 120 and the rear cover 130 are connected by threads, and the driving device protection 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 are easily formed and assembled separately, and after the driving device 200 and the planetary reducer 300 are assembled in the housing 100, the collinear drive joint becomes an independent module. The front cover 120 and the rear cover 130 can be connected by fasteners and are easy to assemble.

[0057] As shown in Figure 5 , Figure 6 , and Figure 7 , the sun gear 321 comprises a connecting shaft portion and a connecting shaft gear portion, the first end of the connecting shaft is coaxially fixed to the motor shaft, and the second end of the connecting shaft is supported on the planet carrier 324 through a bearing, and the motor shaft is supported on the housing 100 through a bearing. The second end of the connecting shaft is inserted into the planet carrier and supported by the bearing, so that the planetary reducer 300 is compact in structure. The motor shaft is coaxially fixed to the sun gear 321, and the motor shaft is coaxially fixed to the rotor 210 under the support of the sun gear 321 and the bearing, which is beneficial to stable rotation of the motor shaft and the sun gear 321, reduces the resistance during rotation, and improves the reliability.

[0058] Embodiment 2

[0059] This embodiment provides a robot joint comprising the collinear drive joint actuator of embodiment 1.

[0060] Embodiment 3

[0061] The present embodiment provides a robot comprising the robot joint of embodiment 2.

[0062] In the description of the present application, it needs to be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are used only to explain the relative positional relationship, movement condition and the like between the components in a certain specific posture, and if the specific posture changes, the directional indication also changes accordingly. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for the purpose of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0063] In the description of the present application, it needs to be understood that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0064] The embodiments of the present application are described above in combination with the drawings, but the present application is not limited to the above specific embodiments, and the above specific embodiments are only illustrative, not restrictive, and those skilled in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims, which are all within the protection of the present application.

Claims

1. A quasi-direct drive joint actuator, characterized in that: include: A housing, a driving device and a planetary reducer, wherein the driving device and the planetary reducer are both installed in the housing; The planetary reducer includes an input gear, a planetary gear train, an output gear and a mounting bracket, wherein the planetary gear train includes a sun gear, planetary gears, a planet carrier, an inner gear ring and a planetary shaft; wherein the input gear is drivingly connected to the output end of the driving device and is fixedly connected to the sun gear, and the input gear, sun gear, planet carrier, inner gear ring and output gear are all coaxial; the planetary gears are mounted on the planetary shafts through bearings, the planetary shafts are fixedly connected to the planet carrier, the planet carrier is fixedly connected to the output gear, the inner gear ring is fixedly connected to the mounting bracket, and the mounting bracket is fixedly connected to the inside of the housing, and the planetary gears are conjugately meshed with the sun gear and the inner gear ring; the driving device is used to drive the sun gear to rotate, thereby driving the planetary gears to rotate, causing the planetary gears to revolve around the inner gear ring, driving the planet carrier to rotate, and then driving the output gear to rotate; The sun gear is a continuous full 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 installed on the planet shaft through bearings. The first planet gear is conjugately meshed with the sun gear, and the second planet gear is conjugately meshed with the inner ring gear.

2. The quasi-direct drive joint actuator according to claim 1, characterized in that: The full elliptical end face tooth profile equation of the sun gear is: ； in, 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 sun gear tooth profile equation, and its value range is , represents a tooth profile period within a domain of definition.

3. The quasi-direct drive joint actuator according to claim 2, characterized in that: The end face tooth profile equation of the double planetary gear is: ； in, To generate the The angle of rotation of the ellipse of the planetary gear end face tooth profile equation around the center; For the The angle of rotation of the planetary gear around the center; For the The angle parameter of the planetary gear end face tooth profile equation has a value range of , To generate the The center of the ellipse of the planetary gear end face tooth profile equation is The center distance of the planetary gear, For the The generation of planetary gears The rotation angle ratio of the ellipse of the planetary gear end face tooth profile equation, 、 To generate the The major and minor axis radii of the ellipse of the planetary gear end face tooth profile equation; ,when When, Planetary gear represents the first planetary gear, when When, The planet gear represents the second planet gear.

4. The quasi-direct drive joint actuator according to claim 3, characterized in that: The tooth profile equation of the inner gear ring is: ； in, is the rotation angle of the second planetary gear around the center; is the rotation angle of the inner gear ring around the center; It is the rotation angle ratio of the second planetary gear and the inner gear ring when they rotate about the fixed axis.

5. The quasi-direct drive joint actuator according to claim 1, characterized in that: The driving device includes a rotor and a stator. The stator is arranged in the housing. The rotor and the stator are coaxially arranged. The rotor is connected to the axis of the sun gear.

6. The quasi-direct drive joint actuator according to claim 5, characterized in that: The rotor is sleeved outside the stator and the planetary reducer, and the stator and the planetary reducer are arranged along the axial direction of the rotor.

7. The quasi-direct drive joint actuator according to claim 1, characterized in that: The housing includes a front cover, a rear cover and a drive device protection 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 device protection cover is installed on the side of the front cover away from the rear cover.

8. A robot joint, characterized in that: It comprises the quasi-direct drive joint actuator as described in any one of claims 1-7.

9. A robot, characterized in that: Comprising the robot joint as claimed in claim 8.

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