Robot joint actuator based on traction engagement gear transmission and design method thereof

Abstract

The application discloses a robot joint actuator based on traction meshing gear transmission, which comprises a shell, a motor driving plate arranged in the shell, a driving device in driving connection with the motor driving plate, the driving device in driving connection with a planetary reducer, and driving force of the driving device being transmitted and output through the planetary reducer; the driving device comprises a stator and a rotor arranged in the shell, the planetary reducer comprises a rotor support rotatably arranged in the shell, and the rotor is arranged in the rotor support as a driving device; the rotor support is in transmission connection with an output wheel rotatably connected to the shell through a planetary gear train. The application discloses a robot joint actuator based on traction meshing gear transmission and a joint design method thereof, smooth power transmission is realized through traction and meshing, periodic impact is reduced, continuous and smooth transmission characteristics are realized, operation noise and vibration are reduced, and high-precision, low-noise and impact-resistant robot joint driving is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of robot joint actuator, in particular to a robot joint actuator based on traction meshing gear transmission and a joint design method thereof. BACKGROUND

[0002] The robot joint actuator in the prior art generally adopts an involute gear transmission reduction device. Although the traditional involute gear transmission reduction mechanism can provide a high reduction ratio and output torque density, it has problems of low transmission accuracy and high running noise caused by gap meshing.

[0003] Nowadays, lightweight, miniaturization, high precision and low noise have become the main direction of the development of the new generation of robots. The periodic contact impact and tooth surface wear of the involute gear meshing mode are becoming increasingly prominent. On the other hand, traction transmission structure has gradually attracted attention. It realizes smooth transmission of force through continuous contact surface, has the advantages of low noise, impact resistance and controllable slip, but the current traction transmission is limited to planar structure or single degree of freedom rolling pair, which is suitable for high precision and low torque transmission, and there is still a lack of traction meshing gear structure that can realize efficient torque transmission and has meshing characteristics.

[0004] Therefore, there is an urgent need for a new traction meshing transmission mechanism to break through the performance bottleneck of the traditional gear reducer, taking into account the accuracy, load capacity, efficiency and compactness of the structure, in order to meet the urgent needs of robot joints. SUMMARY

[0005] The present application overcomes the shortcomings of the prior art and provides a robot joint actuator based on traction meshing gear transmission and a joint design method thereof. The traction and meshing realize smooth power transmission, reduce periodic impact, and realize continuous smooth transmission characteristics. The running noise and vibration are reduced, and the robot joint drive with high precision, low noise and impact resistance is realized.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows: a robot joint actuator based on traction meshing gear transmission, comprising: a housing, a motor drive board is arranged in the housing, and a driving device is drivingly connected with the motor drive board, the driving device is drivingly connected with a planetary reducer, and the driving force of the driving device is transmitted and output through the planetary reducer; the driving device comprises a stator and a rotor arranged in the housing, and the planetary reducer comprises a rotor support rotatably arranged in the housing, and the rotor is arranged in the rotor support as a driving device; the rotor support is drivingly connected with an output wheel rotatably connected to the housing through a planetary gear train.

[0007] In one preferred embodiment of the present application, the planetary gear train comprises a planet carrier, a planet gear, a sun gear and an inner ring gear.

[0008] The two ends of the sun gear are rotatably connected to the planet carrier and the output gear respectively through bearings, and one end of the sun gear is fixedly connected to the rotor support, and the rotor drives the sun gear to rotate.

[0009] Several planetary gears are rotatably connected between the planet carrier and the internal gear ring. These planetary gears are arranged around the outer circumference of the sun gear, and mesh with the outer circumference of the sun gear and the inner circumference of the internal gear ring.

[0010] The driving force of the sun gear is transmitted to the output gear through several planetary gears.

[0011] In a preferred embodiment of the present invention, the sun gear, planet carrier, and internal gear ring are all arranged coaxially;

[0012] One side of the planetary carrier is assembled with the internal gear ring via a bearing, and the other side of the planetary carrier is movably fitted into the internal gear ring.

[0013] In a preferred embodiment of the present invention, the planet carrier is provided with a plurality of spacer slots that accommodate planetary gears at intervals; the planetary gears are rotatably connected in the spacer slots.

[0014] In a preferred embodiment of the present invention, the housing includes a base, an annular groove is provided on the base, a stator is provided in the annular groove, and an annular platform surrounding the annular groove is connected to the output wheel through the bearing.

[0015] In a preferred embodiment of the present invention, the rotor obtains power through a drive device to rotate, which drives the sun gear to rotate, thereby driving the planet gears to revolve around the sun gear while rotating on their own axis, and in turn driving the output wheel to rotate and output torque;

[0016] The radii of the planetary gear cylinders are not equal to the radii of the sun gear cylinders.

[0017] In a preferred embodiment of the present invention, the planetary gear meshes with the sun gear and the internal gear ring, and a spatial conjugate tooth surface consisting of convex teeth and grooves is formed on the cylindrical surface of the sun gear, the cylindrical surface of the planetary gear, and the inner tooth surface of the internal gear ring.

[0018] The radii of the planetary gear cylinder and the radii of the sun gear cylinder are defined as r and R, respectively. If r is less than R, then r is the radius of cylinder one and R is the radius of cylinder two. However, there is no fixed correspondence between r and R and the radii of the planetary gear cylinder and the sun gear cylinder.

[0019] The rotation angle relationship is as follows: t is the rotation angle of the cylinder. The cylinder rotates by two angles;

[0020] The formula for the elliptic curve of the inclined section on cylinder one is:

[0021] ;

[0022] Where u and t are the independent variables. Let be the angle between the ellipse with inclined section on cylinder 1 and the yoz plane;

[0023] The formula for the elliptical section of cylinder one, which unfolds and wraps around cylinder two to form the traction engagement curve, is as follows:

[0024] ;

[0025] The oblique section elliptic curve is extended into an oblique section elliptic surface to form a tubular tooth surface one. The tooth profile formula of the tubular tooth surface one is generated by sweeping the center curve around a fixed radius. The tooth profile formula includes:

[0026] ;

[0027] The traction engagement curve is extended into a curved surface to form a tubular tooth surface. The tooth profile equation of the tubular tooth surface is generated by sweeping the center curve around a fixed radius:

[0028] ;

[0029] in, Let be the pipe radius, and v be a parameter around the pipe cross-section. Let be a unit vector along the z-axis. , They are the tangent vectors, It is the normal vector;

[0030] ;

[0031] ;

[0032] ;

[0033] Gear ratio: .

[0034] In a preferred embodiment of the present invention, a design method for a robot joint actuator based on traction gear transmission is provided, for obtaining a robot joint actuator based on traction gear transmission, comprising: a sun gear and an internal gear ring, both of which are traction gears with grooves. The planetary gears are traction gears with elliptical protruding teeth;

[0035] The equations for the groove surfaces of the sun gear and the internal gear ring are:

[0036] ;

[0037] The equation for the tooth surface of the planetary gear's convex teeth is:

[0038] ;

[0039] Where u is a parameter in the parametric equation, and t is the rotation angle parameter. Let be the angle between the elliptic curve of the inclined section and the yoz plane. Let be the pipe radius, and v be a parameter around the pipe cross-section. Let be a unit vector along the z-axis. , They are the tangent vectors, It is the normal vector;

[0040] The formula for calculating the total reduction ratio of a planetary gear reducer is: , where i is the transmission ratio, R2 is the radius of the internal gear ring, and R1 is the radius of the sun gear.

[0041] In a preferred embodiment of the present invention, a design method for a robot joint actuator based on traction gear transmission is provided, for obtaining a robot joint actuator based on traction gear transmission, comprising: planetary gears being traction gears with convex teeth; an internal gear ring being a traction gear with grooves; and a sun gear being a traction gear with grooves.

[0042] The equations for the convex teeth of both the planetary gears and the internal gear ring are:

[0043] ;

[0044] The equation for the tooth surface of the groove of the sun gear is:

[0045] ;

[0046] Where u is a parameter in the parametric equation, and t is the rotation angle parameter. Let be the angle between the elliptic curve of the inclined section and the yoz plane. Let be the pipe radius, and v be a parameter around the pipe cross-section. Let be a unit vector along the z-axis. , The tangent vector, It is the normal vector;

[0047] The formula for calculating the total reduction ratio of a planetary gear reducer is:

[0048] ;

[0049] Where i is the transmission ratio, R2 is the radius of the internal gear ring, and R1 is the radius of the sun gear.

[0050] In a preferred embodiment of the present invention, the initial phase t and tilt angle are adjusted. One or more translational amounts can generate tooth profiles of various shapes;

[0051] Alternatively, change the initial phase t to rotate the elliptical equidistant surface around the z-axis;

[0052] Or, change the variable This yields elliptical equidistant surfaces with different tilt angles;

[0053] Or, in Add a translation amount to the z-coordinate to translate the elliptical equidistant surface vertically onto cylinder 1.

[0054] This invention addresses the deficiencies in the technical background, and the beneficial technical effects of this invention are:

[0055] This invention discloses a robot joint actuator based on traction meshing gear transmission and its joint design method. It achieves smooth power transmission through traction and meshing, reduces periodic impacts, and realizes continuous and smooth transmission characteristics; it also reduces operating noise and vibration, and achieves high-precision, low-noise, and impact-resistant robot joint drive. Attached Figure Description

[0056] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0057] Figure 1 A schematic diagram of the structure of a robot joint actuator based on traction meshing gears provided in an embodiment of the present invention. Figure 1 ;

[0058] Figure 2 Another structural diagram of the robot joint actuator based on traction meshing gears provided in this embodiment of the invention. Figure 1 ;

[0059] Figure 3 A cross-sectional view of a robot joint actuator based on traction meshing gears provided in an embodiment of the present invention. Figure 1 ;

[0060] Figure 4 Explosion of a robot joint actuator based on traction meshing gears provided in an embodiment of the present invention Figure 1 ;

[0061] Figure 5 Explosion of the planetary reducer provided in the embodiments of the present invention Figure 1 ;

[0062] Figure 6 Explosion of planetary gear train provided in the embodiments of the present invention Figure 1 ;

[0063] Figure 7 The explosion of the sun gear, planet gears, and planet carrier provided in the embodiments of the present inventionFigure 1 ;

[0064] Figure 8 Top view of the meshing of the planetary gear, sun gear, and internal gear ring provided in an embodiment of the present invention. Figure 1 ;

[0065] Figure 9 A schematic diagram of the meshing of a planetary gear and an internal gear ring provided in an embodiment of the present invention. Figure 1 ;

[0066] Figure 10 A schematic diagram of the meshing of the planetary gear, the sun gear, and the internal gear ring provided in an embodiment of the present invention. Figure 1 ;

[0067] Figure 11 Various shapes of traction meshing gear tooth profiles are provided for embodiments of the present invention;

[0068] Figure 12 A cross-sectional view of a robot joint actuator based on traction meshing gears provided in an embodiment of the present invention. Figure 2 ;

[0069] Figure 13 Explosion of the planetary reducer provided in the embodiments of the present invention Figure 2 ;

[0070] Figure 14 Explosion of planetary gear train provided in the embodiments of the present invention Figure 2 ;

[0071] Figure 15 The explosion of the sun gear, planet gears, and planet carrier provided in the embodiments of the present invention Figure 2 ;

[0072] Figure 16 Top view of the meshing of the planetary gear, sun gear, and internal gear ring provided in an embodiment of the present invention. Figure 2 ;

[0073] Figure 17 A schematic diagram of the meshing of a planetary gear and an internal gear ring provided in an embodiment of the present invention. Figure 2 ;

[0074] Figure 18 A schematic diagram of the meshing of the planetary gear, the sun gear, and the internal gear ring provided in an embodiment of the present invention. Figure 2 ;

[0075] In the diagram: 100, housing; 200, motor drive board; 300, planetary reducer; 400, drive unit; 110, base; 120, controller cover; 130, circuit board bracket; 310, rotor bracket; 320, planetary gear train; 330, output gear; 321, planet carrier; 322, planetary gears; 323, sun gear; 324, internal gear ring; 410, stator; 420, rotor. Detailed Implementation

[0076] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. These drawings are simplified schematic diagrams, which are only used to illustrate the basic structure of the present invention and therefore only show the components relevant to the present invention.

[0077] It should be noted that if directional indicators (such as up, down, bottom, top, etc.) are involved in the embodiments of the present invention, these directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly. The terms "first" and "second" 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. Therefore, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature. Unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" 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 direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in the present invention can be understood according to the specific circumstances.

[0078] Example 1, as Figures 1-18 As shown, a robot joint actuator based on traction meshing gear transmission includes: a housing 100, a motor drive plate 200 disposed in the housing 100, and a drive device 400 drivenly connected to the motor drive plate 200. The drive device 400 is drivenly connected to a planetary reducer 300, and the driving force of the drive device 400 is transmitted and output through the planetary reducer 300; the drive device 400 includes a stator 410 and a rotor 420 disposed in the housing 100.

[0079] Specifically, such as Figure 1 , Figure 2 , Figure 3 , Figure 4As shown, the housing 100 includes a base 110, a controller cover 120, and a circuit board bracket 130. The planetary reducer 300 is installed between the circuit board bracket 130 and the base 110. The stator 410 is fixedly connected to the base 110 of the housing 100. The circuit board bracket 130 and the base 110 are connected by threaded fasteners, and the controller cover 120 and the circuit board bracket 130 are also connected by threaded fasteners, facilitating assembly. The motor drive board 200 is located between the controller cover 120 and the circuit board bracket 130. It is mainly used to receive external control commands, obtain the actual position and speed of the rotor 420, use a PID control algorithm to adjust the speed, and excite the stator 410 through electronic commutation technology to generate a rotating magnetic field, thereby precisely driving the rotor 420 to move.

[0080] Specifically, such as Figure 5 As shown, the planetary reducer 300 includes a rotor support 310, a planetary gear train 320, an output wheel 330, and a planet carrier 321. The rotor 420 is installed in the rotor support 310 as a drive unit, and the rotor support 310 is connected to the output wheel 330, which is rotatably connected to the housing 100, via the planetary gear train 320. Furthermore, the planetary gear train 320 includes a planet carrier 321, planet gears 322, a sun gear 323, and an internal gear ring 324. The two ends of the sun gear 323 are rotatably connected to the planet carrier 321 and the output gear 330 respectively through bearings, and one end of the sun gear 323 is fixedly connected to the rotor support 310. The rotor 420 is coaxially connected to the sun gear 323 in the planetary reducer 300, and the rotor 420 drives the sun gear 323 to rotate. Several planet gears 322 are also rotatably connected between the planet carrier 321 and the internal gear ring 324. The several planet gears 322 are arranged on the outer circumference of the sun gear 323, and the planet gears 322 mesh with the outer circumference of the sun gear 323 and the inner circumference of the internal gear ring 324. The driving force of the sun gear 323 is transmitted to the output gear 330 through the several planet gears 322. Furthermore, the sun gear 323, planet carrier 321, and internal gear ring 324 are all coaxially arranged; the planet gear 322 is mounted on the planet carrier 321 by pins. The internal gear ring 324 is fixedly connected to the base 110. One side of the planet carrier 321 is assembled with the internal gear ring 324 via a bearing, and the other side of the planet carrier 321 is movably fitted into the internal gear ring 324. To improve ease of installation, the planet carrier 321 is provided with several spacer slots to accommodate the planet gears 322; the planet gears 322 are rotatably connected in the spacer slots.

[0081] Specifically, the base 110 of the housing 100 is provided with an annular groove, and the stator 410 is arranged in the annular groove. The annular platform around the annular groove is connected to the output wheel 330 through the bearing 2. Specifically, the rotor 420 obtains power from the drive device 400 to rotate, and drives the rotor support 310 to drive the sun gear 323 to rotate, thereby driving the planet gear 322 to revolve around the sun gear 323 while rotating on its own axis, thereby driving the output wheel 330 to rotate and output torque.

[0082] Specifically, in this embodiment, both the sun gear 323 and the internal gear ring 324 are traction gears with grooves. The planet gear 322 is a traction gear with elliptical protruding teeth. For example... Figure 6 , Figure 7 , Figure 8 , Figure 9 and Figure 10 As shown, in this embodiment, four planetary gears 322 are arranged at equal intervals between the sun gear 323 and the internal gear ring 324, and the protruding teeth on the planetary gears 322 engage with the grooves on the sun gear 323 and the internal gear ring 324. Furthermore, the radii of the cylinders of the planetary gears 322 and the cylinders of the sun gear 323 are not equal.

[0083] Working principle:

[0084] In the drive unit 400, the stator 410 is energized to generate a rotating magnetic field. The magnetic field of the rotor 420 strives to align with the rotating magnetic field of the stator 410, thus continuously rotating and outputting torque and speed, thereby driving the sun gear 323 to rotate. The rotor 420 is mounted on the bearing of the planet carrier 321 and is interference-fitted with the sun gear 323, which can better transmit torque and speed.

[0085] Planetary gear 322 meshes with sun gear 323 and internal gear ring 324. Rotor support 310 obtains power from drive device 400 to rotate, which drives sun gear 323 to rotate, thereby driving planetary gear 322 to revolve around sun gear 323 while rotating on its own axis, which in turn drives output gear 330 to rotate and output torque.

[0086] In Embodiment Two, based on Embodiment One, the planetary gear 322 is a traction gear with protruding teeth, and the internal gear ring 324 is a traction gear with grooves. The sun gear 323 is a traction gear with grooves. In this embodiment, four planetary gears 322 are provided. The four planetary gears 322 are arranged at equal intervals between the sun gear 323 and the internal gear ring 324, and the protruding teeth on the planetary gears 322 engage with the grooves on the sun gear 323 and the internal gear ring 324. Considering the difficulty of assembly, semi-circular spacer slots are provided on the outer periphery of the sun gear 323 and the inner periphery of the internal gear ring 324 to facilitate the assembly of the entire planetary gear system 320.

[0087] In Example 3, based on Example 1 or Example 2, the planetary gear 322 meshes with the sun gear 323 and the internal gear ring 324, forming a spatial conjugate tooth surface with convex teeth and grooves on the cylindrical surface of the sun gear 323, the cylindrical surface of the planetary gear 322, and the inner ring tooth surface of the internal gear ring 324.

[0088] Wherein, the radii of the cylinder of planetary gear 322 and the cylinder of sun gear 323 are defined as r and R, respectively, where r is less than R, then r is the radius of cylinder one, and R is the radius of cylinder two. However, there is no fixed correspondence between r and R and the radii of the cylinders of planetary gear 322 and sun gear 323; that is, it includes two sets of patterns, such as... Figures 1-11 As shown, when the radius of the cylinder of planetary gear 322 is greater than the radius of the cylinder of sun gear 323, the radius of the cylinder of planetary gear 322 is R, and the radius of the cylinder of sun gear 323 is r; or, as... Figures 12-18 As shown, when the radius of the cylinder of planetary gear 322 is smaller than the radius of the cylinder of sun gear 323, the radius of the cylinder of planetary gear 322 is r, and the radius of the cylinder of sun gear 323 is R.

[0089] Specifically, cylinder one and cylinder two are tangent to each other and rotate around a fixed axis. In a slip-free transmission, based on the principle of equal linear velocities, the relationship of the rotation angles is as follows: t is the rotation angle of the cylinder. The cylinder rotates by two angles;

[0090] The formula for the elliptic curve of the inclined section on cylinder one is:

[0091] ;

[0092] Where u and t are independent variables. Let be the angle between the ellipse with inclined section on cylinder 1 and the yoz plane;

[0093] The formula for the elliptical section of cylinder one, which unfolds and wraps around cylinder two to form the traction engagement curve, is as follows:

[0094] ;

[0095] The oblique section elliptic curve is extended into an oblique section elliptic surface to form a tubular tooth surface one. The tooth profile formula of the tubular tooth surface one is generated by sweeping the center curve around a fixed radius. The tooth profile formula includes:

[0096] ;

[0097] The traction engagement curve is extended into a curved surface to form a tubular tooth surface. The tooth profile equation of the tubular tooth surface is generated by sweeping the center curve around a fixed radius:

[0098] ;

[0099] in, Let be the pipe radius, and v be a parameter around the pipe cross-section. Let be a unit vector along the z-axis. , The tangent vector, It is the normal vector;

[0100] ;

[0101] ;

[0102] ;

[0103] Gear ratio: .

[0104] Example 4: Based on any of Examples 1 to 3, the initial phase t and tilt angle are adjusted. One or more translational amounts can generate tooth profiles of various shapes.

[0105] For example, changing the initial phase t can cause the elliptical equidistant surface to rotate around the z-axis; or, changing the variable This allows us to obtain elliptical equidistant surfaces with different tilt angles; or, in Add a translation amount to the z-coordinate to translate the elliptical equidistant surface vertically onto cylinder 1.

[0106] Implementation 5, such as Figures 1-11 As shown, a design method for a robot joint actuator based on traction gear transmission is provided to obtain the robot joint actuator based on traction gear transmission as described in Embodiment 1 or Embodiment 3. The method includes: a sun gear 323 and an internal gear ring 324, both of which are traction gears with grooves. The planetary gear 322 is a traction gear with elliptical protruding teeth.

[0107] The equations for the groove surfaces of the sun gear 323 and the internal gear ring 324 are as follows: ;

[0108] The equation of the tooth surface of the convex tooth of planetary gear 322 is:

[0109] ;

[0110] Where u is a parameter in the parametric equation, and t is the rotation angle parameter. Let be the angle between the elliptic curve of the inclined section and the yoz plane. Let be the pipe radius, and v be a parameter around the pipe cross-section. Let be a unit vector along the z-axis. , The tangent vector, It is the normal vector;

[0111] The formula for calculating the total reduction ratio of a planetary reducer 300 is as follows: , where i is the transmission ratio, R2 is the radius of the internal gear ring, and R1 is the radius of the sun gear.

[0112] In Example 6, based on Example 5, considering the dimensions of the housing 100 and the drive device 400, and combining the formula, under the condition of meeting the assembly requirements of each part, the sun gear radius R1 is set to 18, the planet gear 322 radius r is set to 6, and the internal gear ring radius R2 is set to 30, and the total transmission ratio can be calculated to be 2.67.

[0113] Example 7, as Figures 12-18 As shown, a design method for a robot joint actuator based on traction gear transmission is provided to obtain the robot joint actuator based on traction gear transmission of Embodiment 2 or Embodiment 3. The method includes: a planetary gear 322 being a traction gear with protruding teeth; an internal gear ring 324 being a traction gear with grooves; and a sun gear 323 being a traction gear with grooves.

[0114] The equations for the convex teeth of planetary gear 322 and internal gear ring 324 are both:

[0115] ;

[0116] The equation of the tooth surface of the groove of sun gear 323 is: ;

[0117] Where u is a parameter in the parametric equation, and t is the rotation angle parameter. Let be the angle between the elliptic curve of the inclined section and the yoz plane. Let be the pipe radius, and v be a parameter around the pipe cross-section. Let be a unit vector along the z-axis. , The tangent vector, It is the normal vector;

[0118] The formula for calculating the total reduction ratio of a planetary reducer 300 is as follows:

[0119] ;

[0120] Where i is the transmission ratio, R2 is the radius of the internal gear ring, and R1 is the radius of the sun gear.

[0121] In Example 8, based on Example 7, considering the dimensions of the housing 100 and the drive device 400, and combining the formula, under the condition that the assembly requirements of each part are met, the radius R1 of the sun gear is set to 6, the radius r of the planet gear 322 is set to 12, and the radius R2 of the internal gear ring is set to 30, and the total transmission ratio can be calculated to be 6.

[0122] Working principle:

[0123] This invention provides a robot joint actuator based on traction meshing gear transmission and its joint design method, which overcomes the problems of large meshing impact, high noise and low transmission accuracy caused by backlash in traditional involute gears in existing robot joint actuators, and proposes a new joint actuator structure based on traction meshing gear transmission.

[0124] This invention achieves smooth power transmission through traction and meshing on the surfaces of two relatively rolling cylinders (i.e., the sun gear 323 is the inner cylinder and the planet gear 322 is the outer cylinder), by forming matching grooves and elliptical annular protrusions on their respective surfaces. This avoids the periodic impacts caused by the backlash of traditional involute gears, resulting in a continuous and smooth transmission characteristic. This structure not only significantly reduces operating noise and vibration, but also, due to the conjugate meshing of the grooves and elliptical annular protrusions, its geometric characteristics allow for a higher contact area and torque transmission efficiency. This enables a high-precision, low-noise, and impact-resistant robot joint drive solution, suitable for service robots, humanoid robots, medical robots, and precision-operated robotic arms.

[0125] This invention involves two inner and outer cylinders of different radii (i.e., the sun gear 323 is the inner cylinder, and the planet gear 322 is the outer cylinder) rolling relative to each other under non-slip conditions. During transmission, convex teeth and grooves with mathematically defined surfaces are formed on the surfaces of the inner and outer cylinders to create spatial conjugate tooth surfaces, achieving a synergistic effect of traction and meshing. The actuator innovatively adopts a traction meshing gear transmission method, combining traction transmission and meshing characteristics to achieve smooth, efficient, and high-precision power transmission. The core lies in utilizing the conjugate meshing of convex teeth and grooves on the surfaces of the two inner and outer cylinders rolling relative to each other, transmitting torque through a continuous spatial contact surface, avoiding periodic impacts, thereby significantly improving transmission accuracy, reducing noise, and making it suitable for precision fields such as service robots and medical robots. This robot joint actuator mainly consists of a housing 100, a motor drive plate 200, a planetary reducer 300, and a drive unit 400. All components are integrated within the housing 100 to form a compact drive unit. The housing 100 includes a base 110, a controller cover 120, and a circuit board bracket 130, which are connected by threaded fasteners for easy assembly and maintenance. The motor drive board 200 is responsible for processing control commands and driving the motor, while the planetary reducer 300, as the core transmission component, converts the high-speed, low-torque output of the drive unit 400 into a low-speed, high-torque output.

[0126] The above specific embodiments are specific support for the concept proposed in this invention, and should not be used to limit the scope of protection of this invention. Any equivalent changes or modifications made on the basis of this technical solution in accordance with the technical concept proposed in this invention shall still fall within the scope of protection of this invention.

Claims

1. A robot joint actuator based on traction meshing gear transmission, comprising: A housing (100) is provided with a motor drive plate (200) and a drive device (400) drivenly connected to the motor drive plate (200). The drive device (400) is drivenly connected to a planetary reducer (300), and the driving force of the drive device (400) is transmitted and output through the planetary reducer (300). The feature is that: The drive unit (400) includes a stator (410) and a rotor (420) disposed in the housing (100). The planetary reducer (300) includes a rotor support (310) rotatably disposed in the housing (100), and the rotor (420) is disposed in the rotor support (310) as a drive. The rotor support (310) is connected to the output wheel (330) rotatably connected to the housing (100) via the planetary gear train (320). The planetary gear train (320) includes a planet carrier (321), planet gears (322), a sun gear (323), and an internal gear ring (324); The two ends of the sun gear (323) are rotatably connected to the planet carrier (321) and the output wheel (330) respectively through bearings, and one end of the sun gear (323) is fixedly connected to the rotor support (310), and the rotor support (310) is driven by the rotor (420) to drive the sun gear (323) to rotate. A plurality of planetary gears (322) are rotatably connected between the planet carrier (321) and the internal gear ring (324). The plurality of planetary gears (322) are arranged on the outer periphery of the sun gear (323), and the planetary gears (322) mesh with the outer periphery of the sun gear (323) and the inner periphery of the internal gear ring (324). The driving force of the sun gear (323) is transmitted to the output gear (330) through a number of planet gears (322); The planet carrier (321) is provided with a plurality of spaced slots for accommodating planet gears (322); the planet gears (322) are rotatably connected in the spaced slots; The planetary gear (322) meshes with the sun gear (323) and the internal gear ring (324), forming a spatial conjugate tooth surface with convex teeth and grooves on the cylindrical surface of the sun gear (323), the cylindrical surface of the planetary gear (322), and the inner ring tooth surface of the internal gear ring (324). The radius of the cylinder of the planetary gear (322) and the radius of the cylinder of the sun gear (323) are defined as r and R respectively. If r is less than R, then r is the radius of cylinder one and R is the radius of cylinder two. However, there is no fixed correspondence between r and R and the radius of the cylinder of the planetary gear (322) and the radius of the cylinder of the sun gear (323). The rotation angle relationship is as follows: t is the rotation angle of the cylinder. The cylinder rotates by two angles; The formula for the elliptic curve of the inclined section on cylinder one is: ； Where u and t are the independent variables, and u is the parameter in the parametric equation. Let be the angle between the ellipse with inclined section on cylinder 1 and the yoz plane; The formula for the elliptical section of cylinder one, which unfolds and wraps around cylinder two to form the traction engagement curve, is as follows: ； The oblique section elliptic curve is extended into an oblique section elliptic surface to form a tubular tooth surface one. The tooth profile formula of the tubular tooth surface one is generated by sweeping the center curve around a fixed radius. The tooth profile formula includes: ； The traction engagement curve is extended into a curved surface to form a tubular tooth surface. The tooth profile equation of the tubular tooth surface is generated by sweeping the center curve around a fixed radius: ； in, Let be the pipe radius, and v be a parameter around the pipe cross-section. Let be a unit vector along the z-axis. , They are the tangent vectors, It is the normal vector; ； ； ； Gear ratio: .

2. The robot joint actuator based on traction meshing gear transmission according to claim 1, characterized in that: The sun gear (323), planet carrier (321) and internal gear ring (324) are all arranged coaxially; One side of the planetary carrier (321) is assembled with the internal gear ring (324) via a bearing, and the other side of the planetary carrier (321) is movably fitted into the internal gear ring (324).

3. A robot joint actuator based on traction meshing gear transmission according to claim 2, characterized in that: The housing (100) includes a base (110), on which an annular groove is provided, and a stator (410) is provided in the annular groove. The annular platform surrounding the annular groove is connected to the output wheel (330) through the bearing.

4. A robot joint actuator based on traction meshing gear transmission according to claim 3, characterized in that: The rotor (420) obtains power through the drive device (400) to rotate. The rotor (420) drives the rotor support (310) to drive the sun gear (323) to rotate, thereby driving the planet gear (322) to revolve around the sun gear (323) while rotating on its own axis, which in turn drives the output wheel (330) to rotate and output torque. The radius of the cylinder of the planetary gear (322) is not equal to the radius of the cylinder of the sun gear (323).

5. A design method for a robot joint actuator based on traction meshing gear transmission, characterized in that: The robot joint actuator based on traction meshing gear transmission as described in claim 1 includes: a sun gear (323) and an internal gear ring (324) are both traction meshing gears with grooves; and a planet gear (322) is a traction meshing gear with elliptical protrusions. The groove surface equations of the sun gear (323) and the internal gear ring (324) are as follows: ; The equation of the tooth surface of the convex tooth of the planetary gear (322) is: ； Where u is a parameter in the parametric equation, and t is the rotation angle parameter. Let be the angle between the elliptic curve of the inclined section and the yoz plane. Let be the pipe radius, and v be a parameter around the pipe cross-section. Let be a unit vector along the z-axis. , They are the tangent vectors, It is the normal vector; The formula for calculating the total reduction ratio of the planetary reducer (300) is as follows: , where i is the transmission ratio, R2 is the radius of the internal gear ring, and R1 is the radius of the sun gear.

6. A design method for a robot joint actuator based on traction meshing gear transmission, characterized in that: The robot joint actuator based on traction meshing gear transmission as described in claim 1 includes: a planetary gear (322) being a traction meshing gear with protruding teeth; an internal gear ring (324) being a traction meshing gear with grooves; and a sun gear (323) being a traction meshing gear with grooves. The equations for the convex teeth of the planetary gear (322) and the internal gear ring (324) are as follows: ； The equation of the tooth surface of the groove of the sun gear (323) is: ； Where u is a parameter in the parametric equation, and t is the rotation angle parameter. Let be the angle between the elliptic curve of the inclined section and the yoz plane. Let be the pipe radius, and v be a parameter around the pipe cross-section. Let be a unit vector along the z-axis. , The tangent vector, It is the normal vector; The formula for calculating the total reduction ratio of the planetary reducer (300) is as follows: ； Where i is the transmission ratio, R2 is the radius of the internal gear ring, and R1 is the radius of the sun gear.

7. A design method for a robot joint actuator based on traction meshing gear transmission according to claim 5 or 6, characterized in that: By adjusting the initial phase t and tilt angle One or more translational amounts can generate tooth profiles of various shapes; Alternatively, change the initial phase t to rotate the elliptical equidistant surface around the z-axis; Or, change the variable This allows us to obtain elliptical equidistant surfaces with different tilt angles. Or, in Add a translation amount to the z-coordinate to translate the elliptical equidistant surface vertically onto cylinder 1.

Images